Sample records for optimize welding conditions

  1. Combinatorial optimization of welding

    E-Print Network [OSTI]

    Sóbester, András

    C E D C Combinatorial optimization of welding sequences The problem Combinatorial optimization a welding example of a tail bearing housing vanes ­ Figure 1. The major structural details are the outer ring, the inner ring and the vanes. The vanes are welded to the rings using TIG welding. Fig. 1: Tail

  2. Novel Optimization Methodology for Welding Process/Consumable Integration

    SciTech Connect (OSTI)

    Quintana, Marie A; DebRoy, Tarasankar; Vitek, John; Babu, Suresh

    2006-01-15T23:59:59.000Z

    Advanced materials are being developed to improve the energy efficiency of many industries of future including steel, mining, and chemical, as well as, US infrastructures including bridges, pipelines and buildings. Effective deployment of these materials is highly dependent upon the development of arc welding technology. Traditional welding technology development is slow and often involves expensive and time-consuming trial and error experimentation. The reason for this is the lack of useful predictive tools that enable welding technology development to keep pace with the deployment of new materials in various industrial sectors. Literature reviews showed two kinds of modeling activities. Academic and national laboratory efforts focus on developing integrated weld process models by employing the detailed scientific methodologies. However, these models are cumbersome and not easy to use. Therefore, these scientific models have limited application in real-world industrial conditions. On the other hand, industrial users have relied on simple predictive models based on analytical and empirical equations to drive their product development. The scopes of these simple models are limited. In this research, attempts were made to bridge this gap and provide the industry with a computational tool that combines the advantages of both approaches. This research resulted in the development of predictive tools which facilitate the development of optimized welding processes and consumables. The work demonstrated that it is possible to develop hybrid integrated models for relating the weld metal composition and process parameters to the performance of welds. In addition, these tools can be deployed for industrial users through user friendly graphical interface. In principle, the welding industry users can use these modular tools to guide their welding process parameter and consumable composition selection. It is hypothesized that by expanding these tools throughout welding industry, substantial energy savings can be made. Savings are expected to be even greater in the case of new steels, which will require extensive mapping over large experimental ranges of parameters such as voltage, current, speed, heat input and pre-heat.

  3. A shape optimization formulation of weld pool determination. , A. Ellabibb

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    The determination of temperature field in a welding process permits the control of mechanical effects (residual consists in finding the weld pool and T the temperature gradient in the workpiece, solution of: K T xA shape optimization formulation of weld pool determination. A. Chakiba , A. Ellabibb , A

  4. SOAR: An extensible suite of codes for weld analysis and optimal weld schedules

    SciTech Connect (OSTI)

    Eisler, G.R.; Fuerschbach, P.W.

    1997-07-01T23:59:59.000Z

    A suite of MATLAB-based code modules has been developed to provide optimal weld schedules, regulating weld process parameters for CO2 and pulse Nd:YAG laser welding methods, and arc welding in support of the Smartweld manufacturing initiative at Sandia National Laboratories. The optimization methodology consists of mixed genetic and gradient-based algorithms to query semi-empirical, nonlinear algebraic models. The optimization output provides heat-input-efficient welds for user-specified weld dimensions. User querying of all weld models is available to examine sub-optimal schedules. In addition, a heat conduction equation solver for 2-D heat flow is available to provide the user with an additional check of weld thermal effects. The inclusion of thermodynamic properties allows the extension of the empirical models to include materials other than those tested. All solution methods are provided with graphical user interfaces and display pertinent results in two and three-dimensional form. The code architecture provides an extensible framework to add an arbitrary number of modules.

  5. Resistance spot welding of ultra-fine grained steel sheets produced by constrained groove pressing: Optimization and characterization

    SciTech Connect (OSTI)

    Khodabakhshi, F.; Kazeminezhad, M., E-mail: mkazemi@sharif.edu; Kokabi, A.H.

    2012-07-15T23:59:59.000Z

    Constrained groove pressing as a severe plastic deformation method is utilized to produce ultra-fine grained low carbon steel sheets. The ultra-fine grained sheets are joined via resistance spot welding process and the characteristics of spot welds are investigated. Resistance spot welding process is optimized for welding of the sheets with different severe deformations and their results are compared with those of as-received samples. The effects of failure mode and expulsion on the performance of ultra-fine grained sheet spot welds have been investigated in the present paper and the welding current and time of resistance spot welding process according to these subjects are optimized. Failure mode and failure load obtained in tensile-shear test, microhardness, X-ray diffraction, transmission electron microscope and scanning electron microscope images have been used to describe the performance of spot welds. The region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. The results show that optimum welding parameters (welding current and welding time) for ultra-fine grained sheets are shifted to lower values with respect to those for as-received specimens. In ultra-fine grained sheets, one new region is formed named recrystallized zone in addition to fusion zone, heat affected zone and base metal. It is shown that microstructures of different zones in ultra-fine grained sheets are finer than those of as-received sheets. - Highlights: Black-Right-Pointing-Pointer Resistance spot welding process is optimized for joining of UFG steel sheets. Black-Right-Pointing-Pointer Optimum welding current and time are decreased with increasing the CGP pass number. Black-Right-Pointing-Pointer Microhardness at BM, HAZ, FZ and recrystallized zone is enhanced due to CGP.

  6. OPTIMIZATION STUDY FOR FILL STEM MANUFACTURINGAND PINCH WELD PROCESSING

    SciTech Connect (OSTI)

    Korinko, P; Karl Arnold, K

    2006-09-06T23:59:59.000Z

    A statistically designed experiment was conducted as part of a six sigma project for Fill Stem Manufacturing and Pinch Weld Processing. This multi-year/multi-site project has successfully completed a screening study and used those results as inputs to this optimization study. Eleven welds were made using fairly tight current and cycle range. The welds demonstrate increased burst strength, longer closure length, more net displacement, and improved bond rating with increased current. However, excessive melting remains a concern from a processing viewpoint and may cause adverse metallurgical interactions. Therefore, the highest current levels specified cannot be utilized. A Validation Study is proposed for the Defense Programs Inert Facility.

  7. Optimization Online - Optimality conditions for various efficient ...

    E-Print Network [OSTI]

    Truong Xuan Duc Ha

    2010-08-02T23:59:59.000Z

    Aug 2, 2010 ... Optimality conditions for various efficient solutions involving coderivatives: from set-valued optimization problems to set-valued equilibrium...

  8. Evaluation of weld porosity in laser beam seam welds: optimizing continuous wave and square wave modulated processes.

    SciTech Connect (OSTI)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew; Faraone, Kevin M. (Honeywell FM& T, Kansas City, MO); Roach, Robert Allen; Norris, Jerome T.

    2007-02-01T23:59:59.000Z

    Nd:YAG laser joining is a high energy density (HED) process that can produce high-speed, low-heat input welds with a high depth-to-width aspect ratio. This is optimized by formation of a ''keyhole'' in the weld pool resulting from high vapor pressures associated with laser interaction with the metallic substrate. It is generally accepted that pores form in HED welds due to the instability and frequent collapse of the keyhole. In order to maintain an open keyhole, weld pool forces must be balanced such that vapor pressure and weld pool inertia forces are in equilibrium. Travel speed and laser beam power largely control the way these forces are balanced, as well as welding mode (Continuous Wave or Square Wave) and shielding gas type. A study into the phenomenon of weld pool porosity in 304L stainless steel was conducted to better understand and predict how welding parameters impact the weld pool dynamics that lead to pore formation. This work is intended to aid in development and verification of a finite element computer model of weld pool fluid flow dynamics being developed in parallel efforts and assist in weld development activities for the W76 and future RRW programs.

  9. Multi-mode ultrasonic welding control and optimization

    DOE Patents [OSTI]

    Tang, Jason C.H.; Cai, Wayne W

    2013-05-28T23:59:59.000Z

    A system and method for providing multi-mode control of an ultrasonic welding system. In one embodiment, the control modes include the energy of the weld, the time of the welding process and the compression displacement of the parts being welded during the welding process. The method includes providing thresholds for each of the modes, and terminating the welding process after the threshold for each mode has been reached, the threshold for more than one mode has been reached or the threshold for one of the modes has been reached. The welding control can be either open-loop or closed-loop, where the open-loop process provides the mode thresholds and once one or more of those thresholds is reached the welding process is terminated. The closed-loop control provides feedback of the weld energy and/or the compression displacement so that the weld power and/or weld pressure can be increased or decreased accordingly.

  10. Further Development at JET of Remote Digital Photogrammetry Techniques and Remote Welding Under Conditions of Restricted Access

    E-Print Network [OSTI]

    Further Development at JET of Remote Digital Photogrammetry Techniques and Remote Welding Under Conditions of Restricted Access

  11. Multi-objective optimization of laser-welded steel sandwich panels for static loads using a genetic algorithm

    E-Print Network [OSTI]

    Vel, Senthil

    ], or brazing [6]. In comparison, laser welding of the core to the face-sheets in a steel sandwich panel systemMulti-objective optimization of laser-welded steel sandwich panels for static loads using a genetic 2012 Accepted 19 October 2012 Keywords: Structural optimization Laser welding Steel sandwich panels

  12. Optimality conditions of set-valued optimization p...

    E-Print Network [OSTI]

    2011-05-03T23:59:59.000Z

    Optimality conditions of set-valued optimization problem involving relative algebraic interior in ordered linear spaces. Zhi-Ang Zhoua, Xin-Min Yangb and...

  13. A quantitative determination of the conditions for hot cracking during welding for aluminum alloys

    E-Print Network [OSTI]

    Steenbergen, James Everett

    1969-01-01T23:59:59.000Z

    A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE January 1969 Major Subject: Materials Engineering A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN (Chairman of Committee) ( ead...

  14. A quantitative determination of the conditions for hot cracking during welding for aluminum alloys

    E-Print Network [OSTI]

    Steenbergen, James Everett

    1969-01-01T23:59:59.000Z

    A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE January 1969 Major Subject: Materials Engineering A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN (Chairman of Committee) ( ead...

  15. Optimized Sampling Frequencies for Weld Reliability Assessments of Long Pipeline Segments

    E-Print Network [OSTI]

    Kreinovich, Vladik

    p. If this probability exceeds a certain regulated (small) threshold p 0 , the pipeline must. To be on the safe side, regulations require that a pipeline be repaired when it is possible that p ?? p 0 , iOptimized Sampling Frequencies for Weld Reliability Assessments of Long Pipeline Segments Cesar J

  16. Optimized Sampling Frequencies for Weld Reliability Assessments of Long Pipeline Segments

    E-Print Network [OSTI]

    Kreinovich, Vladik

    p. If this probability exceeds a certain regulated (small) threshold p0, the pipeline must. To be on the safe side, regulations require that a pipeline be repaired when it is possible that p p0, i.e., when pOptimized Sampling Frequencies for Weld Reliability Assessments of Long Pipeline Segments Cesar J

  17. Numerical Analysis of Metal Transfer in Gas Metal Arc Welding under Modified Pulsed Current Conditions

    E-Print Network [OSTI]

    Zhang, YuMing

    causes a thermal load too high to apply to thin sectioned or heat-sensitive materials. In an effort was assumed as the boundary condition for the calculation of the electromagnetic force. The calculations were agreement between calculation and experimental results. I. INTRODUCTION IN gas metal arc welding (GMAW

  18. Optimization of Air Conditioning Cycling

    E-Print Network [OSTI]

    Seshadri, Swarooph

    2012-10-19T23:59:59.000Z

    on a 3-ton residential air conditioner are then presented to intuitively understand the effect of expansion valve and evaporator fan cycling in a real system. A real time optimization method is explored and the feasibility, recommendations for a...

  19. Use Computational Model to Design and Optimize Welding Conditions to

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group current C3EDepartment of Energy OfficeFact Sheet Uranium Mill

  20. Optimization Online - Calculating optimal conditions for alloy and ...

    E-Print Network [OSTI]

    Aimen E. Gheribi

    2010-12-21T23:59:59.000Z

    Dec 21, 2010 ... Calculating optimal conditions for alloy and process design using thermodynamic and property databases, the FactSage software ... is maximized or minimized during annealing or rolling; other calculated functions such as ... which the objectives and constraints are typically outputs of computer simulations.

  1. Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds under Lap Shear Loading Conditions

    SciTech Connect (OSTI)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2008-06-01T23:59:59.000Z

    This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS) under lap shear loading condition. DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. Static weld strength tests using lap shear samples were performed on the joint populations with various fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with conventionally required fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 welds under lap shear loading. Moreover, failure mode has strong influence on weld peak load and energy absorption for all the DP800 welds and the TRIP800 small welds: welds failed in pullout mode have statistically higher strength and energy absorption than those failed in interfacial fracture mode. For TRIP800 welds above the critical fusion zone level, the influence of weld failure modes on peak load and energy absorption diminishes. Scatter plots of peak load and energy absorption versus weld fusion zone size were then constructed, and the results indicate that fusion zone size is the most critical factor in weld quality in terms of peak load and energy absorption for both DP800 and TRIP800 spot welds.

  2. First and second order optimality conditions for optimal control ...

    E-Print Network [OSTI]

    2012-05-16T23:59:59.000Z

    This paper deals with optimal control problems of integral equations, ... Keywords Optimal control, integral equations, state constraints, second-order op-.

  3. Optimization of Experimental Conditions for Biodiesel Production

    E-Print Network [OSTI]

    Ayoola Ayodeji A; Hymore Fredrick K; E Mathew A; Udeh Ifeoma N

    Abstract-- This study is based on optimizing the experimental conditions of biodiesel production by base-catalyzed transesterification using waste cooking oil (WCO). In this study, the key parameters varied were methanol (20, 25, 30, 35, and 40%), sodium hydroxide (0.4, 0.6, 0.8, 0.9 and 1.0g), reaction time (40, 60, 90, 100 and 120 minutes) and reaction temperature (50, 52, 55, 58, and 60 o C). Maximum biodiesel yield of 86 % was obtained at optimum conditions of 30 % methanol concentration, 0.4g of NaOH concentration, 60 o C reaction temperature and 90 minutes of operation. Biodiesel produced meets American Standard of Testing and Materials (ASTM) standards of biodiesel fuel: viscosity (4.0564 4.9824cSt), density (0.8790 0.8819g/cm 3), flash point (157 168 o C), pour point (0 to-3 o C) and calculated cetane index (7.45 8.26). Index Term-- Biodiesel, fossil fuel, methanol, transesterification, waste cooking oil.

  4. OPTIMALITY CONDITIONS FOR IRREGULAR INEQUALITY-CONSTRAINED PROBLEMS

    E-Print Network [OSTI]

    Solodov, Mikhail V.

    OPTIMALITY CONDITIONS FOR IRREGULAR INEQUALITY-CONSTRAINED PROBLEMS A. F. IZMAILOV AND M. V­Optimization, and by FAPERJ. 1280 #12;IRREGULAR INEQUALITY-CONSTRAINED PROBLEMS 1281 Note that in (1.4) cone K is not required

  5. Neutron and x-ray scattering studies of the metallurgical condition and residual stresses in Weldalite welds

    SciTech Connect (OSTI)

    Spooner, S. [Oak Ridge National Lab., TN (United States); Pardue, E.B.S. [Technology for Energy Corp., Knoxville, TN (United States)

    1995-12-31T23:59:59.000Z

    Weldalite is a lithium-containing aluminum alloy which is being considered for aerospace applications because its favorable strength-to-weight ratio. Successful welding of this alloy depends on the control of the metallurgical condition and residual stresses in the heat affected zone. Neutron and x-ray scattering methods of residual stress measurement were applied to plasma arc welds made in aluminum-lithium alloy test panels as part of an evaluation of materials for use in welded structures. In the course of these studies discrepancies between x-ray and neutron results from the heat affected zone (HAZ) of the weld were found. Texture changes and recovery from the cold work, indicated in peak widths, were found in the HAZ as well. The consideration of x-ray and neutron results leads to the conclusion that there is a change in solute composition which modifies the d-spacings in the HAZ which affects the neutron diffraction determination of residual stresses. The composition changes give the appearance of significant compressive strains in the HAZ. This effect and sharp gradients in the texture give severe anomalies in the neutron measurement of residual stress. The use of combined x-ray and neutron techniques and the solution to the minimizing of the neutron diffraction anomalies are discussed.

  6. Necessary optimality conditions for multiobjective bilevel programs

    E-Print Network [OSTI]

    2010-08-23T23:59:59.000Z

    The multiobjective bilevel program is a sequence of two optimization prob- ... ence for vectors in W. We consider the following multiobjective bilevel program-.

  7. Relaxing the Optimality Conditions of Box QP

    E-Print Network [OSTI]

    2007-10-26T23:59:59.000Z

    Oct 23, 2007 ... Proof. The argument is based on examining an optimal solution for the dual of ..... Numerical methods for large-scale non-convex quadratic pro-.

  8. Nonlinear chance constrained problems: optimality conditions ...

    E-Print Network [OSTI]

    2015-07-08T23:59:59.000Z

    Jul 8, 2015 ... Si jk := E(Ri ?ERi)(Rj ?ERj)(Rk ?ERk). If we employ the aggregate function approach of multiobjective optimization with aggregation parameter.

  9. Modelling of Casting, Welding, and Advanced Solidification Processing XI NON-MONOTONE TEMPERATURE BOUNDARY CONDITIONS

    E-Print Network [OSTI]

    Lowengrub, John

    Modelling of Casting, Welding, and Advanced Solidification Processing XI NON-MONOTONE TEMPERATURE anisotropy, such as a needle crystal or dendrite, the interface can develop periodic non-monotone temperature in the equilibrium temperature close to the highly curved tip. This minimum results in the tip temperature itself

  10. Investigation of electromagnetic welding

    E-Print Network [OSTI]

    Pressl, Daniel G. (Daniel Gerd)

    2009-01-01T23:59:59.000Z

    We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...

  11. PDC IC WELD FAILURE EVALUATION AND RESOLUTION

    SciTech Connect (OSTI)

    Korinko, P.; Howard, S.; Maxwell, D.; Fiscus, J.

    2012-04-16T23:59:59.000Z

    During final preparations for start of the PDCF Inner Can (IC) qualification effort, welding was performed on an automated weld system known as the PICN. During the initial weld, using a pedigree canister and plug, a weld defect was observed. The defect resulted in a hole in the sidewall of the canister, and it was observed that the plug sidewall had not been consumed. This was a new type of failure not seen during development and production of legacy Bagless Transfer Cans (FB-Line/Hanford). Therefore, a team was assembled to determine the root cause and to determine if the process could be improved. After several brain storming sessions (MS and T, R and D Engineering, PDC Project), an evaluation matrix was established to direct this effort. The matrix identified numerous activities that could be taken and then prioritized those activities. This effort was limited by both time and resources (the number of canisters and plugs available for testing was limited). A discovery process was initiated to evaluate the Vendor's IC fabrication process relative to legacy processes. There were no significant findings, however, some information regarding forging/anneal processes could not be obtained. Evaluations were conducted to compare mechanical properties of the PDC canisters relative to the legacy canisters. Some differences were identified, but mechanical properties were determined to be consistent with legacy materials. A number of process changes were also evaluated. A heat treatment procedure was established that could reduce the magnetic characteristics to levels similar to the legacy materials. An in-situ arc annealing process was developed that resulted in improved weld characteristics for test articles. Also several tack welds configurations were addressed, it was found that increasing the number of tack welds (and changing the sequence) resulted in decreased can to plug gaps and a more stable weld for test articles. Incorporating all of the process improvements for the actual can welding process, however, did not result in an improved weld geometry. Several possibilities for the lack of positive response exist, some of which are that (1) an insufficient number of test articles were welded under prototypic conditions, (2) the process was not optimized so that significant improvements were observable over the 'noise', and (3) the in-situ arc anneal closed the gap down too much so the can was unable to exhaust pressure ahead of the weld. Several operational and mechanical improvements were identified. The weld clamps were changed to a design consistent with those used in the legacy operations. A helium puff operation was eliminated; it is believed that this operation was the cause of the original weld defect. Also, timing of plug mast movement was found to correspond with weld irregularities. The timing of the movement was changed to occur during weld head travel between tacks. In the end a three sequential tack weld process followed by a pulse weld at the same current and travel speed as was used for the legacy processes was suggested for use during the IC qualification effort. Relative to legacy welds, the PDC IC weld demonstrates greater fluctuation in the region of the weld located between tack welds. However, canister weld response (canister to canister) is consistent and with the aid of the optical mapping system (for targeting the cut position) is considered adequate. DR measurements and METs show the PDC IC welds to have sufficient ligament length to ensure adequate canister pressure/impact capacity and to ensure adequate stub function. The PDC welding process has not been optimized as a result of this effort. Differences remain between the legacy BTC welds and the PDC IC weld, but these differences are not sufficient to prevent resumption of the current PDC IC qualification effort. During the PDC IC qualification effort, a total of 17 cans will be welded and a variety of tests/inspections will be performed. The extensive data collected during that qualification effort should be of a sufficient population to determ

  12. Fusion Welding of AerMet 100 Alloy

    SciTech Connect (OSTI)

    ENGLEHART, DAVID A.; MICHAEL, JOSEPH R.; NOVOTNY, PAUL M.; ROBINO, CHARLES V.

    1999-08-01T23:59:59.000Z

    A database of mechanical properties for weldment fusion and heat-affected zones was established for AerMet{reg_sign}100 alloy, and a study of the welding metallurgy of the alloy was conducted. The properties database was developed for a matrix of weld processes (electron beam and gas-tungsten arc) welding parameters (heat inputs) and post-weld heat treatment (PWHT) conditions. In order to insure commercial utility and acceptance, the matrix was commensurate with commercial welding technology and practice. Second, the mechanical properties were correlated with fundamental understanding of microstructure and microstructural evolution in this alloy. Finally, assessments of optimal weld process/PWHT combinations for cotildent application of the alloy in probable service conditions were made. The database of weldment mechanical properties demonstrated that a wide range of properties can be obtained in welds in this alloy. In addition, it was demonstrated that acceptable welds, some with near base metal properties, could be produced from several different initial heat treatments. This capability provides a means for defining process parameters and PWHT's to achieve appropriate properties for different applications, and provides useful flexibility in design and manufacturing. The database also indicated that an important region in welds is the softened region which develops in the heat-affected zone (HAZ) and analysis within the welding metallurgy studies indicated that the development of this region is governed by a complex interaction of precipitate overaging and austenite formation. Models and experimental data were therefore developed to describe overaging and austenite formation during thermal cycling. These models and experimental data can be applied to essentially any thermal cycle, and provide a basis for predicting the evolution of microstructure and properties during thermal processing.

  13. Optimization of well rates under gas coning conditions

    E-Print Network [OSTI]

    Urbanczyk, Christopher Henry

    1989-01-01T23:59:59.000Z

    production rates under gas caning conditions. This new method applies to an oil reservoir overlain by a large gas cap containing multiple wells. The cases consider have a limit on the maximum field production rate for both oil and gas. It was found... that the optimal p~ion rates are achieved when Eq. 1 is satisfied for any pair of wells i and j: ) I = constant i = 1, . . . , n dqo This condition minimizes the f ield gas production rate when the maximum field production rate for oil is met, and maximizes...

  14. Weld penetration and defect control

    SciTech Connect (OSTI)

    Chin, B.A.

    1992-05-15T23:59:59.000Z

    Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

  15. Characterization of Gas Metal Arc Welding welds obtained with new high Cr-Mo ferritic stainless steel filler wires

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    1 Characterization of Gas Metal Arc Welding welds obtained with new high Cr-Mo ferritic stainless Several compositions of metal cored filler wire were manufactured to define the best welding conditions for homogeneous welding, by Gas Metal Arc Welding (GMAW) process, of a modified AISI 444 ferritic stainless steel

  16. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    SciTech Connect (OSTI)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03T23:59:59.000Z

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  17. Welding apparatus and methods for using ultrasonic sensing

    DOE Patents [OSTI]

    McJunkin, Timothy R.; Johnson, John A.; Larsen, Eric D.; Smartt, Herschel B.

    2006-08-22T23:59:59.000Z

    A welding apparatus using ultrasonic sensing is described and which includes a movable welder having a selectively adjustable welding head for forming a partially completed weld in a weld seam defined between adjoining metal substrates; an ultrasonic assembly borne by the moveable welder and which is operable to generate an ultrasonic signal which is directed toward the partially completed weld, and is further reflected from same; and a controller electrically coupled with the ultrasonic assembly and controllably coupled with the welding head, and wherein the controller receives information regarding the ultrasonic signal and in response to the information optimally positions the welding head relative to the weld seam.

  18. Experimental investigation of welding penetration-depth in high-purity aluminium

    SciTech Connect (OSTI)

    Tong, W. [Babcock and Wilcox, Lynchburg, VA (United States). Naval Nuclear Fuel Div.

    1996-12-31T23:59:59.000Z

    One of the most important parameters in the superconducting splice design is the welding penetration-depth because it determines the electrical resistivity across the welded joints through the high-purity aluminum stabilizers. Highly resistive welds could lead to conductor instability when the superconductor goes normal. In the present investigation, experiments were performed using gas tungsten-arc welding to identify the effects of the welding parameters on the penetration-depth. The experimental results will be applied to the optimization of the superconducting splice design. The mock-up test data and theoretical analysis have shown that the higher energy input and lower welding speed produce the deeper penetration-depth in high-purity aluminum. In order to achieve an approximately uniform penetration-depth, three methods were explored: (i) a starting-delay at the welding start point, (ii) an external cooling, and (iii) staggered overlapping weldments. The experimental results have suggested that a uniform penetration-depth can be obtained under the thermal equilibrium welding conditions.

  19. Automatic monitoring of vibration welding equipment

    DOE Patents [OSTI]

    Spicer, John Patrick; Chakraborty, Debejyo; Wincek, Michael Anthony; Wang, Hui; Abell, Jeffrey A; Bracey, Jennifer; Cai, Wayne W

    2014-10-14T23:59:59.000Z

    A vibration welding system includes vibration welding equipment having a welding horn and anvil, a host device, a check station, and a robot. The robot moves the horn and anvil via an arm to the check station. Sensors, e.g., temperature sensors, are positioned with respect to the welding equipment. Additional sensors are positioned with respect to the check station, including a pressure-sensitive array. The host device, which monitors a condition of the welding equipment, measures signals via the sensors positioned with respect to the welding equipment when the horn is actively forming a weld. The robot moves the horn and anvil to the check station, activates the check station sensors at the check station, and determines a condition of the welding equipment by processing the received signals. Acoustic, force, temperature, displacement, amplitude, and/or attitude/gyroscopic sensors may be used.

  20. Laser welding of fused quartz

    DOE Patents [OSTI]

    Piltch, Martin S.; Carpenter, Robert W.; Archer III, McIlwaine

    2003-06-10T23:59:59.000Z

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  1. Phase transformations in welded supermartensitic stainless steels

    E-Print Network [OSTI]

    Carrouge, Dominique

    - ferrite phase, and the development of a model to facilitate the choice of a suitable post-weld heat-treatment temperature. The microstructural examination of a variety of welds revealed the presence of retained ?-ferrite in dual-phase and grain... -coarsened HAZ regions. Under normal welding conditions, ?-ferrite retention was more pronounced in dual-phase HAZ and in molybdenum containing alloys. However, in multipass welds, ?-ferrite distribution was non-uniform as a result of reheating effects. A number...

  2. WELDING RESEARCH -s11WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -s11WELDING JOURNAL ABSTRACT. Double-electrode gas metal arc welding (DE-GMAW) is a novel weld- ing process recently developed to increase welding productivity while maintaining the base its non- consumable tungsten electrode with a consumable welding wire electrode result- ing in a new

  3. WELDING RESEARCH -s85WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -s85WELDING JOURNAL ABSTRACT. Measurement of weld pool surface is a difficult but urgent task in the welding community. It plays an important role not only in developing the next- generation intelligent welding machines but also for modeling complex welding processes. In recent years

  4. WELDING RESEARCH -s229WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -s229WELDING JOURNAL ABSTRACT. Dual-bypass gas metal arc welding (DB agrees with experimental data. Introduction Gas metal arc welding (GMAW) is an arc welding process- minum alloy welded structures have been widely applied. The use of aluminum as an alternative material

  5. Optimization Online - Sufficient Conditions for Low-rank Matrix ...

    E-Print Network [OSTI]

    Lingchen Kong

    2011-06-15T23:59:59.000Z

    Jun 15, 2011 ... This class of optimization problems is $NP$-hard and a popular approach replaces the rank function with the nuclear norm of the matrix...

  6. Optimality conditions for the nonlinear programming problems on ...

    E-Print Network [OSTI]

    2012-11-28T23:59:59.000Z

    In recent years, there is an increasing interest on the topic of the optimization methods on ..... From the proof on page 52 in Clarke (1983), we have 0 ?.

  7. Simulation and Optimization of Wind Farm Operations under Stochastic Conditions

    E-Print Network [OSTI]

    Byon, Eunshin

    2011-08-08T23:59:59.000Z

    This dissertation develops a new methodology and associated solution tools to achieve optimal operations and maintenance strategies for wind turbines, helping reduce operational costs and enhance the marketability of wind generation. The integrated...

  8. Weld penetration and defect control. Final report

    SciTech Connect (OSTI)

    Chin, B.A.

    1992-05-15T23:59:59.000Z

    Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

  9. WELDING RESEARCH -s57WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -s57WELDING JOURNAL ABSTRACT. Low heat input is typically desired for welding high welding. However, a high current, and thus a high heat input, is required to melt more wire to achieve the HAZ size, microstructure, and the hard- ness of high-strength steel ASTM A514 welded by DE

  10. WELDING RESEARCH -S237WELDING JOURNAL

    E-Print Network [OSTI]

    Cambridge, University of

    WELDING RESEARCH -S237WELDING JOURNAL We depend in our everyday life on the performance of vast the tallest building in the world -- Fig. 1. These are all made from steel and rely on welding for their assembly. Weld Design: Experiment or Model? A weld is a heterogeneity introduced into a carefully

  11. WELDING RESEARCH -s87WELDING JOURNAL

    E-Print Network [OSTI]

    Eagar, Thomas W.

    WELDING RESEARCH -s87WELDING JOURNAL ABSTRACT. Welding fume contains ele- ments that, in their pure of welding fume must be examined when considering fume toxicity. Various chemical analysis techniques are pre techniques to analyze the chemistry of mild steel welding fume. X-ray diffraction (XRD) shows that mild steel

  12. WELDING RESEARCH -s231WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -s231WELDING JOURNAL ABSTRACT. Double-electrode gas metal arc welding (DE the welding wire and the bypass torch. To control the base metal current at the desired level, a group. Introduction Gas metal arc welding (GMAW) is a major process for metals joining. Conventional GMAW is normally

  13. Increasing Productivity of Welding

    E-Print Network [OSTI]

    Uhrig, J. J.

    1983-01-01T23:59:59.000Z

    It is universally recognized that welding is the most economical way to permanently join metals. Recent advances in welding, specifically, the continuous electrode wire processes make welding even more attractive for manufacturing. As welding...

  14. Increasing Productivity of Welding

    E-Print Network [OSTI]

    Uhrig, J. J.

    1983-01-01T23:59:59.000Z

    It is universally recognized that welding is the most economical way to permanently join metals. Recent advances in welding, specifically, the continuous electrode wire processes make welding even more attractive for manufacturing. As welding...

  15. WELDING RESEARCH ~----------------------~--~ SUPPLEMENT TO THE WELDING JOURNAL. FEBRUARY 1990

    E-Print Network [OSTI]

    Eagar, Thomas W.

    J ) WELDING RESEARCH ~----------------------~--~ SUPPLEMENT TO THE WELDING JOURNAL. FEBRUARY 1990 Sponsored by the American Welding Society and the Welding Research Council All papers published in the Welding Journal's Welding Research Supplement undergo Peer Review before publication for: I) originality

  16. Microstructure of Titanium Welds

    SciTech Connect (OSTI)

    Danielson, Paul; Wilson, Rick D.; Alman, David E.

    2003-02-01T23:59:59.000Z

    Plates of commercially pure titanium were welded and microscopically analyzed to understand the influence of joining variables on weld microstructure.

  17. Wonder Weld

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    Engineers at the U.S. Department of Energy's Princeton Plasma Physics Laboratory are using the process shown here to create a super-strong weld for the upgrade of a key component of the Lab's experimental nuclear fusion reactor.

  18. Pulsed Magnetic Welding for Advanced Core and Cladding Steel

    SciTech Connect (OSTI)

    Cao, Guoping; Yang, Yong

    2013-12-19T23:59:59.000Z

    To investigate a solid-state joining method, pulsed magnetic welding (PMW), for welding the advanced core and cladding steels to be used in Generation IV systems, with a specific application for fuel pin end-plug welding. As another alternative solid state welding technique, pulsed magnetic welding (PMW) has not been extensively explored on the advanced steels. The resultant weld can be free from microstructure defects (pores, non-matallic inclusions, segregation of alloying elements). More specifically, the following objectives are to be achieved, 1) To design a suitable welding apparatus fixture, and optimize welding parameters for repeatable and acceptable joining of the fuel pin end-plug. The welding will be evaluated using tensile tests for lap joint weldments and helium leak tests for the fuel pin end-plug. 2) investigate the microstructural and mechanical properties changes in PMW weldments of proposed advanced core and cladding alloys. 3) Simulate the irradiation effects on the PWM weldments using ion irradiation.

  19. Fatique Resistant, Energy Efficient Welding Program, Final Technical Report

    SciTech Connect (OSTI)

    Egland, Keith; Ludewig, Howard

    2006-05-25T23:59:59.000Z

    The program scope was to affect the heat input and the resultant weld bead geometry by synchronizing robotic weave cycles with desired pulsed waveform shapes to develop process parameters relationships and optimized pulsed gas metal arc welding processes for welding fatique-critical structures of steel, high strength steel, and aluminum. Quality would be addressed by developing intelligent methods of weld measurement that accurately predict weld bead geometry from process information. This program was severely underfunded, and eventually terminated. The scope was redirected to investigate tandem narrow groove welding of steel butt joints during the one year of partial funding. A torch was designed and configured to perform a design of experiments of steel butt weld joints that validated the feasability of the process. An initial cost model estimated a 60% cost savings over conventional groove welding by eliminating the joint preparation and reducing the weld volume needed.

  20. On Sufficient Conditions for Testing Optimality of Codewords in ISI Channels

    E-Print Network [OSTI]

    Kavcic, Aleksandar

    On Sufficient Conditions for Testing Optimality of Codewords in ISI Channels Fabian Lim1 if a codeword is optimal, for intersymbol interference (ISI) channels. I. INTRODUCTION The maximum interference (ISI) channels, where (channel) memory is present. The techniques for the memoryless channels

  1. COMPARISON OF AIR AND DEUTERIUM ON PINCH WELD BOND APPEARANCE

    SciTech Connect (OSTI)

    Korinko, P

    2005-10-11T23:59:59.000Z

    The effect that air and deuterium internal atmospheres have on the pinch weld bond quality was evaluated by conducting a scoping study using type 304L stainless steel LF-7 test stems that were fabricated for an associated study. Welds were made under cool, yet nominal conditions to exacerbate the influence of the atmosphere. The bond quality of the welds was directly related to the internal atmosphere with the air atmosphere welds being of lower quality than the deuterium atmosphere welds for nominally identical welding conditions.

  2. Optimal working conditions for thermoelectric generators with realistic thermal coupling

    E-Print Network [OSTI]

    Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P

    2011-01-01T23:59:59.000Z

    We study how maximum output power can be obtained from a thermoelectric generator(TEG) with nonideal heat exchangers. We demonstrate with an analytic approach based on a force-flux formalism that the sole improvement of the intrinsic characteristics of thermoelectric modules including the enhancement of the figure of merit is of limited interest: the constraints imposed by the working conditions of the TEG must be considered on the same footing. Introducing an effective thermal conductance we derive the conditions which permit maximization of both efficiency and power production of the TEG dissipatively coupled to heat reservoirs. Thermal impedance matching must be accounted for as well as electrical impedance matching in order to maximize the output power. Our calculations also show that the thermal impedance does not only depend on the thermal conductivity at zero electrical current: it also depends on the TEG figure of merit. Our analysis thus yields both electrical and thermal conditions permitting optima...

  3. WELDING RESEARCH -s77WELDING JOURNAL

    E-Print Network [OSTI]

    DuPont, John N.

    WELDING RESEARCH -s77WELDING JOURNAL ABSTRACT. The microstructure of AL- 6XN plates joined via a double-sided fric- tion stir weld has been investigated. The microstructural zones that develop during friction stir welding (FSW) reflect de- creasing strains and less severe thermal cy- cles with increasing

  4. WELDING RESEARCH -S249WELDING JOURNAL

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH -S249WELDING JOURNAL ABSTRACT. Double-sided arcing uses two torches on the opposite sides of the workpiece to force the welding current to flow through the thickness. If a keyhole is established through the thickness, part of the welding current will flow through the keyhole and maintain

  5. WELDING RESEARCH -s51WELDING JOURNAL

    E-Print Network [OSTI]

    DuPont, John N.

    WELDING RESEARCH -s51WELDING JOURNAL ABSTRACT. Electron microprobe analy- sis was utilized to examine the gradient of alloying elements across the weld inter- face of austenitic/ferritic dissimilar alloy welds. The concentration gradients were converted to martensite start (Ms) tem- perature gradients

  6. WELDING RESEARCH -s281WELDING JOURNAL

    E-Print Network [OSTI]

    DuPont, John N.

    WELDING RESEARCH -s281WELDING JOURNAL ABSTRACT. Superaustenitic stainless steel alloys can often pose difficulties dur- ing fusion welding due to the unavoidable microsegregation of Mo and tramp ele. A method of producing austenitic welds is proposed that can po- tentially circumvent these issues by de

  7. WELDING RESEARCH -S125WELDING JOURNAL

    E-Print Network [OSTI]

    DuPont, John N.

    WELDING RESEARCH -S125WELDING JOURNAL ABSTRACT. Microstructural evolution and solidification cracking susceptibility of dissimilar metal welds between AL- 6XN super austenitic stainless steel and two, differential thermal analysis, and Varestraint testing tech- niques. Welds were prepared over the en- tire

  8. Method and apparatus for real time weld monitoring

    DOE Patents [OSTI]

    Leong, Keng H. (Lemont, IL); Hunter, Boyd V. (Bolingbrook, IL)

    1997-01-01T23:59:59.000Z

    An improved method and apparatus are provided for real time weld monitoring. An infrared signature emitted by a hot weld surface during welding is detected and this signature is compared with an infrared signature emitted by the weld surface during steady state conditions. The result is correlated with weld penetration. The signal processing is simpler than for either UV or acoustic techniques. Changes in the weld process, such as changes in the transmitted laser beam power, quality or positioning of the laser beam, change the resulting weld surface features and temperature of the weld surface, thereby resulting in a change in the direction and amount of infrared emissions. This change in emissions is monitored by an IR sensitive detecting apparatus that is sensitive to the appropriate wavelength region for the hot weld surface.

  9. Narrow gap laser welding

    DOE Patents [OSTI]

    Milewski, John O. (Santa Fe, NM); Sklar, Edward (Santa Fe, NM)

    1998-01-01T23:59:59.000Z

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

  10. Narrow gap laser welding

    DOE Patents [OSTI]

    Milewski, J.O.; Sklar, E.

    1998-06-02T23:59:59.000Z

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

  11. Optimized estimates of the regularity of the conditional distribution of the sample mean

    E-Print Network [OSTI]

    Victor Chulaevsky

    2015-04-24T23:59:59.000Z

    We give an improved estimate for the regularity of the conditional distribution of the empiric mean of a finite sample of IID random variables, conditional on the sample "fluctuations", extending the well-known property of Gaussian IID samples. Specifically, we replace the bounds in probability, established in our earlier works, by those in distribution, and this results in the optimal regularity exponent in the final estimate.

  12. The Size of the Sensitization Zone in 304 Stainless Steel Welds

    E-Print Network [OSTI]

    Eagar, Thomas W.

    . Single-pass, bead-on-plate welds were made by gas tungsten arc welding on 30-cm/30-cm/ 1.3-cm 304 that the width of the sensitization zone is in proportion to the magnitude ofthe heat input, except when very heat distrihution. Under certain welding conditions, one can obwin welds which are free ofsensitization

  13. Sufficient Conditions for Optimal Multicast Communication Barbara D. Birchler, AbdolHossein Esfahanian, and Eric Torng

    E-Print Network [OSTI]

    Torng, Eric

    ­1266 fbirchler,esfahani,torngg@cps.msu.edu Abstract In this paper, we give a general technique for com­ puting will satisfy these conditions, this result essentially means that multicast can always be performed in dlog(d+1 to be a shortest path routing scheme, this result essentially implies that any real system allows optimal multicast

  14. Optimal Wind Conditions for the Survival of Larval Northern Anchovy, Engraulis mordax

    E-Print Network [OSTI]

    . There is a statistically sig- nificant relation between larva mortality rate and the frequency of calm, low wind speed periOptimal Wind Conditions for the Survival of Larval Northern Anchovy, Engraulis mordax: A Modeling- puter modeling. The hypothesis was as follows. While wind events dissipate layers of planktonic food

  15. Development of a comprehensive weld process model

    SciTech Connect (OSTI)

    Radhakrishnan, B.; Zacharia, T.; Paul, A.

    1997-05-01T23:59:59.000Z

    This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC`s expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three-dimensional (3-D) welding simulation model which was developed by LMES which is capable of predicting weld pool shape and the temperature history in 3-d single-pass welds. However, the model does not account for multipass welds, microstructural evolution, distortion and residual stresses. Additionally, the model requires large resources of computing time, which limits its use for practical applications. To overcome this, CTC and LMES have developed through this CRADA the comprehensive welding simulation model described above.

  16. A Glove Box Enclosed Gas-Tungsten Arc Welding System

    SciTech Connect (OSTI)

    Reevr, E, M; Robino, C.V.

    1999-07-01T23:59:59.000Z

    This report describes an inert atmosphere enclosed gas-tungsten arc welding system which has been assembled in support of the MC2730, MC2730A and MC 3500 Radioisotope Thermoelectric Generator (RTG) Enhanced Surveillance Program. One goal of this program is to fabricate welds with microstructures and impurity levels which are similar to production heat source welds previously produced at Los Alamos National Laboratory and the Mound Facility. These welds will subsequently be used for high temperature creep testing as part of the overall component lifetime assessment. In order to maximize the utility of the welding system, means for local control of the arc atmosphere have been incorporated and a wide range of welding environments can easily be evaluated. The gas-tungsten arc welding system used in the assembly is computer controlled, includes two-axis and rotary motion, and can be operated in either continuous or pulsed modes. The system can therefore be used for detailed research studies of welding impurity effects, development of prototype weld schedules, or to mimic a significant range of production-like welding conditions. Fixturing for fabrication of high temperature creep test samples have been designed and constructed, and weld schedules for grip-tab and test welds have been developed. The microstructure of these welds have been evaluated and are consistent with those used during RTG production.

  17. Effect of Scratches on Pinch Welds

    SciTech Connect (OSTI)

    Korinko, P

    2005-10-11T23:59:59.000Z

    Fill stems for tritium reservoirs have stringent scratch requirements such that any indications that appear to have depth are cause for rework or rejection. A scoping study was undertaken to evaluate the effect of scratches approximately 0.0015 to 0.002 inch deep on the fitness for service and bond quality. The stems were characterized using borescope before and after welding. The four stems were welded with near optimal weld parameters, proof tested, and examined metallographically. The stems were radiographed, proof tested, and examined metallographically. The scratches did not adversely affect (1) the weld integrity based on radiography, (2) the ability to withstand the proof pressure, and (3) the weld quality based on metallographic cross-sections. Based on these limited results at a nominal weld current, the weld process is very robust. It may be able to recover from manufacturing defects and inspection anomalies worse than those expected for typical fill stem manufacturing processes; additional testing specific to each application over a range of weld heats is needed to verify applicability of these results.

  18. Model Based Optimal Sensor Network Design for Condition Monitoring in an IGCC Plant

    SciTech Connect (OSTI)

    Kumar, Rajeeva; Kumar, Aditya; Dai, Dan; Seenumani, Gayathri; Down, John; Lopez, Rodrigo

    2012-12-31T23:59:59.000Z

    This report summarizes the achievements and final results of this program. The objective of this program is to develop a general model-based sensor network design methodology and tools to address key issues in the design of an optimal sensor network configuration: the type, location and number of sensors used in a network, for online condition monitoring. In particular, the focus in this work is to develop software tools for optimal sensor placement (OSP) and use these tools to design optimal sensor network configuration for online condition monitoring of gasifier refractory wear and radiant syngas cooler (RSC) fouling. The methodology developed will be applicable to sensing system design for online condition monitoring for broad range of applications. The overall approach consists of (i) defining condition monitoring requirement in terms of OSP and mapping these requirements in mathematical terms for OSP algorithm, (ii) analyzing trade-off of alternate OSP algorithms, down selecting the most relevant ones and developing them for IGCC applications (iii) enhancing the gasifier and RSC models as required by OSP algorithms, (iv) applying the developed OSP algorithm to design the optimal sensor network required for the condition monitoring of an IGCC gasifier refractory and RSC fouling. Two key requirements for OSP for condition monitoring are desired precision for the monitoring variables (e.g. refractory wear) and reliability of the proposed sensor network in the presence of expected sensor failures. The OSP problem is naturally posed within a Kalman filtering approach as an integer programming problem where the key requirements of precision and reliability are imposed as constraints. The optimization is performed over the overall network cost. Based on extensive literature survey two formulations were identified as being relevant to OSP for condition monitoring; one based on LMI formulation and the other being standard INLP formulation. Various algorithms to solve these two formulations were developed and validated. For a given OSP problem the computation efficiency largely depends on the size of the problem. Initially a simplified 1-D gasifier model assuming axial and azimuthal symmetry was used to test out various OSP algorithms. Finally these algorithms were used to design the optimal sensor network for condition monitoring of IGCC gasifier refractory wear and RSC fouling. The sensors type and locations obtained as solution to the OSP problem were validated using model based sensing approach. The OSP algorithm has been developed in a modular form and has been packaged as a software tool for OSP design where a designer can explore various OSP design algorithm is a user friendly way. The OSP software tool is implemented in Matlab/Simulink in-house. The tool also uses few optimization routines that are freely available on World Wide Web. In addition a modular Extended Kalman Filter (EKF) block has also been developed in Matlab/Simulink which can be utilized for model based sensing of important process variables that are not directly measured through combining the online sensors with model based estimation once the hardware sensor and their locations has been finalized. The OSP algorithm details and the results of applying these algorithms to obtain optimal sensor location for condition monitoring of gasifier refractory wear and RSC fouling profile are summarized in this final report.

  19. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    SciTech Connect (OSTI)

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15T23:59:59.000Z

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce compressive residual stress at weld toe for weld fatigue resistance.

  20. Automated Spot Weld Inspection using Infrared Thermography

    SciTech Connect (OSTI)

    Chen, Jian [ORNL] [ORNL; Zhang, Wei [ORNL] [ORNL; Yu, Zhenzhen [ORNL] [ORNL; Feng, Zhili [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    An automated non-contact and non-destructive resistance spot weld inspection system based on infrared (IR) thermography was developed for post-weld applications. During inspection, a weld coupon was heated up by an auxiliary induction heating device from one side of the weld, while the resulting thermal waves on the other side were observed by an IR camera. The IR images were analyzed to extract a thermal signature based on normalized heating time, which was then quantitatively correlated to the spot weld nugget size. The use of normalized instead of absolute IR intensity was found to be useful in minimizing the sensitivity to the unknown surface conditions and environment interference. Application of the IR-based inspection system to different advanced high strength steels, thickness gauges and coatings were discussed.

  1. Optimal Deployment of Thermal Energy Storage under Diverse Economic and Climate Conditions

    SciTech Connect (OSTI)

    DeForest, Nicolas; Mendes, Goncalo; Stadler, Michael; Feng, Wei; Lai, Judy; Marnay, Chris

    2014-04-15T23:59:59.000Z

    This paper presents an investigation of the economic benefit of thermal energy storage (TES) for cooling, across a range of economic and climate conditions. Chilled water TES systems are simulated for a large office building in four distinct locations, Miami in the U.S.; Lisbon, Portugal; Shanghai, China; and Mumbai, India. Optimal system size and operating schedules are determined using the optimization model DER-CAM, such that total cost, including electricity and amortized capital costs are minimized. The economic impacts of each optimized TES system is then compared to systems sized using a simple heuristic method, which bases system size as fraction (50percent and 100percent) of total on-peak summer cooling loads. Results indicate that TES systems of all sizes can be effective in reducing annual electricity costs (5percent-15percent) and peak electricity consumption (13percent-33percent). The investigation also indentifies a number of criteria which drive TES investment, including low capital costs, electricity tariffs with high power demand charges and prolonged cooling seasons. In locations where these drivers clearly exist, the heuristically sized systems capture much of the value of optimally sized systems; between 60percent and 100percent in terms of net present value. However, in instances where these drivers are less pronounced, the heuristic tends to oversize systems, and optimization becomes crucial to ensure economically beneficial deployment of TES, increasing the net present value of heuristically sized systems by as much as 10 times in some instances.

  2. Heat flow during the autogenous GTA welding of pipes

    SciTech Connect (OSTI)

    Kou, S.; Le, Y.

    1984-06-01T23:59:59.000Z

    A theoretical and experimental study of heat flow during the welding of pipes was carried out. The theoretical part of the study involves the development of two finite difference computer models: one for describing steady state, 3-dimensional heat flow during seam welding, the other for describing unsteady state, 3-dimensional heat flow during girth welding. The experimental part of the study, on the other hand, includes: measurement of the thermal response of the pipe with a high speed data acquisition system, determination of the arc efficiency with a calorimeter, and examination of the fusion boundary of the resultant weld. The experimental results were compared with the calculated ones, and the agreement was excellent in the case of seam welding and reasonably good in the case of girth welding. Both the computer models and experiments confirmed that, under a constant heat input and welding speed, the size of the fusion zone remains unchanged in seam welding but continues to increase in girth welding of pipes of small diameters. It is expected that the unsteady state model developed can be used to provide optimum conditions for girth welding, so that uniform weld beads can be obtained and weld defects such as lack of fusion and sagging can be avoided.

  3. WELDING RESEARCH SUPPLEMENT TO THE WELDING JOURNAL, JUNE, 1982

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) WELDING RESEARCH SUPPLEMENT TO THE WELDING JOURNAL, JUNE, 1982 Sponsored by the American Welding Society .1mJ the Welding Research Council The Effect of Electrical Resistance on Nugget Formation During Spot Welding Applying a higher resistance coating to HSLA steel increases the welding current range

  4. WELDING RESEARCH ~------------~-~ SUPPLEMENT TO THE WELDING JOURNAL, AUGUST 1989

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) WELDING RESEARCH ~------------~-~ SUPPLEMENT TO THE WELDING JOURNAL, AUGUST 1989 Sponsored by the American Welding Society and the Welding Research Council All papers published in the Welding Journal's Welding Research Supplement undergo Peer Review before publication for: 1) originality of the contribution

  5. Development of a Comprehensive Weld Process Model

    SciTech Connect (OSTI)

    Radhakrishnan, B.; Zacharia, T.

    1997-05-01T23:59:59.000Z

    This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC's expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three- dimensional (3-D) welding simulation model which was developed by LMES which is capable of predicting weld pool shape and the temperature history in 3-d single-pass welds. However, the model does not account for multipass welds, microstructural evolution, distortion and residual stresses. Additionally, the model requires large resources of computing time, which limits its use for practical applications. To overcome this, CTC and LMES have developed through this CRADA the comprehensive welding simulation model described above. The following technical tasks have been accomplished as part of the CRADA. 1. The LMES welding code has been ported to the Intel Paragon parallel computer at ORNL. The timing results illustrate the potential of the modified computer model for the analysis of large-scale welding simulations. 2. The kinetics of grain structure evolution in the weld heat affected zone (HAZ) has been simulated with reasonable accuracy by coupling an improved MC grain growth algorithm with a methodology for converting the MC parameters of grain size and time to real parameters. The simulations effectively captured the thermal pinning phenomenon that has been reported in the weld HAZ. 3. A cellular automaton (CA) code has been developed to simulate the solidification microstructure in the weld fusion zone. The simulations effectively captured the epitaxial growth of the HAZ grains, the grain selection mechanism, and the formation of typical grain structures observed in the weld t%sion zone. 4. The point heat source used in the LMES welding code has ben replaced with a distributed heat source to better capture the thermal characteristics and energy distributions in a commercial welding heat source. 5. Coupled thermal-mechanical and metallurgical models have been developed to accurately predict the weld residual stresses, and 6. Attempts have been made to integrate the newly developed computational capabilities into a comprehensive weld design tool.

  6. Fusion welding process

    DOE Patents [OSTI]

    Thomas, Kenneth C. (Export, PA); Jones, Eric D. (Salem, PA); McBride, Marvin A. (Hempfield Township, Westmoreland County, PA)

    1983-01-01T23:59:59.000Z

    A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

  7. Analysis of oscillation characteristics and optimal conditions for high power operation of Gyrotron FU CW GIII

    SciTech Connect (OSTI)

    Tatematsu, Y., E-mail: tatema@fir.u-fukui.ac.jp; Yamaguchi, Y.; Kawase, T.; Ichioka, R.; Ogawa, I.; Saito, T.; Idehara, T. [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

    2014-08-15T23:59:59.000Z

    The oscillation characteristics of Gyrotron FU CW GIII and its wave frequency and output power dependences on the magnetic field strength, the gun coil current, and the anode voltage were investigated experimentally. The experimental results were analyzed theoretically using a self-consistent code that included the electron properties in the cavity, corresponding to the actual operating conditions in the experiments. As a result, it was found that the variation in frequency with the magnetic field strength was related to an axial profile change in the electromagnetic wave in the cavity. In addition, the optimal condition that gives the maximum output power was found to be determined by the pitch factor rather than by the electron beam radius under the given operating conditions.

  8. Application of Genetic Algorithm to Optimal Design of Central Air-Conditioning Water System

    E-Print Network [OSTI]

    Feng, X.; Zou, Y.; Long, W.

    2006-01-01T23:59:59.000Z

    .25 150 121.86 0.1182 1.92 200 131.55 0.0218 376.9729 1.0864 19 19 20 4.5 150 99.58 0.1013 1.57 150 107.18 0.1013 1163.561 1.6857 20 20 21 1.8 80 22.29 0.965 1.17 65 24.28 2.3884 1408.019 1.8046 21 22 23 1 80 22.29 0.5361 1.17 80 24.24 0.5361 315.0493... Wuxi, P. R. China, 214122 Shanghai? P. R. China, 200070 fxp_99@126.com Zouyun_22@126.com WeidingLong@163.com Abstract: The optimal design of air-conditioning water system is an optimization problem of functions that depend on a series...

  9. c 1997 by Jay H. Lee, Jin Hoon Choi, and Kwang Soon Lee 3.3 NECESSARY CONDITION OF OPTIMALITY

    E-Print Network [OSTI]

    Hong, Deog Ki

    c 1997 by Jay H. Lee, Jin Hoon Choi, and Kwang Soon Lee 3.3 NECESSARY CONDITION OF OPTIMALITY 0 g2x = x , b 0 + rfx = 0 is not the necessary condition of optimality anymore. 59 #12;c 1997 dxxdxy = 0 m For any y = Pm i=1 ai dhi dx x, yTdxy = 0 60 #12;c 1997 by Jay H. Lee, Jin Hoon Choi

  10. Method for welding beryllium

    DOE Patents [OSTI]

    Dixon, Raymond D. (Los Alamos, NM); Smith, Frank M. (Espanola, NM); O'Leary, Richard F. (Los Alamos, NM)

    1997-01-01T23:59:59.000Z

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon.

  11. Optimization of Fuel Cell System Operating Conditions for Fuel Cell Vehicles

    E-Print Network [OSTI]

    Zhao, Hengbing; Burke, Andy

    2008-01-01T23:59:59.000Z

    A.F. Burke, Modeling and Optimization of PEMFC Systems andPEM Fuel Cell System Optimization, Proceedings of the 2 ndof the fuel cell system optimization model Fig. 5 Flowchart

  12. Mechanical Properties of Aluminum Tailor Welded Blanks at Superplastic Temperatures

    SciTech Connect (OSTI)

    Davies, Richard W.; Vetrano, John S.; Smith, Mark T.; Pitman, Stan G.

    2002-10-06T23:59:59.000Z

    This paper describes an investigation of the mechanical properties of weld material in aluminum tailor welded blanks (TWB) at superplastic temperatures and discusses the potential application of TWBs in superplastic forming operations. Aluminum TWBs consist of multiple sheet materials of different thickness or alloy that are butt-welded together into a single, variable thickness blank. To evaluate the performance of the weld material in TWBs, a series of tensile tests were conducted at superplastic temperatures with specimens that contained weld material in the gage area. The sheet material used in the study was Sky 5083 aluminum alloy, which was joined to produce the TWBs by gas tungsten arc welding using an AA5356 filler wire. The experimental results show that, in the temperature range of 500?C to 550?C and at strain rates ranging from 10-4 sec-1 to 10-2 sec-1, the weld material has a higher flow stress and lower ductility than the monolithic sheet material. The weld material exhibited elongations of 40% to 60% under these conditions, whereas the monolithic sheet achieved 220% to 360% elongation. At the same temperatures and strain rates, the weld material exhibited flow stresses 1.3 to 4 times greater than the flow stress in the monolithic sheet. However, the weld material did show a substantial increase in the strain rate sensitivity and ductility when compared to the same material formed at room temperature.

  13. Exploring High-Dimensional Data Space: Identifying Optimal Process Conditions in Photovoltaics: Preprint

    SciTech Connect (OSTI)

    Suh, C.; Glynn, S.; Scharf, J.; Contreras, M. A.; Noufi, R.; Jones, W. B.; Biagioni, D.

    2011-07-01T23:59:59.000Z

    We demonstrate how advanced exploratory data analysis coupled to data-mining techniques can be used to scrutinize the high-dimensional data space of photovoltaics in the context of thin films of Al-doped ZnO (AZO), which are essential materials as a transparent conducting oxide (TCO) layer in CuInxGa1-xSe2 (CIGS) solar cells. AZO data space, wherein each sample is synthesized from a different process history and assessed with various characterizations, is transformed, reorganized, and visualized in order to extract optimal process conditions. The data-analysis methods used include parallel coordinates, diffusion maps, and hierarchical agglomerative clustering algorithms combined with diffusion map embedding.

  14. Resistance Spot Welding of Galvanized Steel: Part I. Material Variations and Process Modifications

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ( l Resistance Spot Welding of Galvanized Steel: Part I. Material Variations and Process to determine their effects on the acceptable range of resistance spot welding conditions for galvanized steel upsloping and downsloping of the weld current, preheat current, postheat current, electrode tip geometry

  15. EVALUATION OF CONSTANT CURRENT WELD CONTROL FOR PINCH WELDING

    SciTech Connect (OSTI)

    Korinko, P; STANLEY, S; HOWARD, H

    2005-10-11T23:59:59.000Z

    Modern weld controllers typically use current to control the weld process. SRS uses a legacy voltage control method. This task was undertaken to determine if the improvements in the weld control equipment could be implemented to provide improvements to the process control. The constant current mode of operation will reduce weld variability by about a factor of 4. The constant voltage welds were slightly hotter than the constant current welds of the same nominal current. The control mode did not appear to adversely affect the weld quality, but appropriate current ranges need to be established and a qualification methodology for both welding and shunt calibrations needs to be developed and documented.

  16. Dissimilar-alloy laser welding of titanium: Ti6Al-4V to Beta-C{trademark}

    SciTech Connect (OSTI)

    Liu, P.S.; Baeslack, W.A. III; Hurley, J.

    1994-12-31T23:59:59.000Z

    Beta-C{sup TM} is a metastable-beta titanium alloy (nominal composition: Ti-3wt%Al-8wt%V-6wtTCr-4wt%Mo-4wt%Zr) which can be thermomechanically processed and heat treated to provide excellent combinations of strength, ductility, and fracture toughness. Recently, the increased application of metastable-beta titanium alloys in aerospace and commercial applications has resulted in the necessity to join these alloys to conventional alpha-beta titanium alloys. Based on this previous work, two approaches were considered for improving the ductility of dissimilar-alloy welds between Ti-6Al-4V and Beta-C{sup TM} in the present study: (1) application of a low heat input welding process to minimize the fusion zone and heat-affected zone (HAZ) beta grain size and (2) modification of the fusion zone chemical composition to allow greater microstructural optimization through postweld aging. CO{sub 2} laser welds were produced between Ti-6Al-4V and Beta-C{sup TM} sheet. Three different nominal fusion zone chemical compositions were obtained by varying the laser beam locations relative to the joint centerline and thereby melting different quantities of each base metal. For comparable postweld aging conditions, the laser welds exhibited ductilities superior to those of coarse-grained gas tungsten arc welds. Fracture analysis of the weld zone revealed a transition from a predominantly transgranular fracture in the low-temperature aged conditions to increasingly intergranular fracture following aging at higher temperature. This transition was promoted by an increase in the thickness and continuity of alpha phase at beta grain boundaries.

  17. Dual wire welding torch and method

    DOE Patents [OSTI]

    Diez, Fernando Martinez (Peoria, IL); Stump, Kevin S. (Sherman, IL); Ludewig, Howard W. (Groveland, IL); Kilty, Alan L. (Peoria, IL); Robinson, Matthew M. (Peoria, IL); Egland, Keith M. (Peoria, IL)

    2009-04-28T23:59:59.000Z

    A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

  18. Computer modeling of arc welds to predict effects of critical variables on weld penetration

    SciTech Connect (OSTI)

    Zacharia, T.; David, S.A.

    1991-01-01T23:59:59.000Z

    In recent years, there have been several attempts to study the effect of critical variables on welding by computational modeling. It is widely recognized that temperature distributions and weld pool shapes are keys to quality weldments. It would be very useful to obtain relevant information about the thermal cycle experienced by the weld metal, the size and shape of the weld pool, and the local solidification rates, temperature distributions in the heat-affected zone (HAZ), and associated phase transformations. The solution of moving boundary problems, such as weld pool fluid flow and heat transfer, that involve melting and/or solidification is inherently difficult because the location of the solid-liquid interface is not known a priori and must be obtained as a part of the solution. Because of non-linearity of the governing equations, exact analytical solutions can be obtained only for a limited number of idealized cases. Therefore, considerable interest has been directed toward the use of numerical methods to obtain time-dependant solutions for theoretical models that describe the welding process. Numerical methods can be employed to predict the transient development of the weld pool as an integral part of the overall heat transfer conditions. The structure of the model allows each phenomenon to be addressed individually, thereby gaining more insight into their competing interactions. 19 refs., 6 figs., 1 tab.

  19. Passive Acoustic Detection of Wind Turbine In-Flow Conditions for Active Control and Optimization

    SciTech Connect (OSTI)

    Murray, Nathan E.

    2012-03-12T23:59:59.000Z

    Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predicted could provide a benefit to the wind energy industry as a whole. Based on the fundamental coupling of velocity fluctuations to pressure fluctuations in the nearly incompressible flow in the ABL, This work hypothesizes that a ground-based array of infrasonic pressure transducers could be employed to estimate the vertical wind profile over a height relevant for wind turbines. To analyze this hypothesis, experiments and field deployments were conducted. Wind tunnel experiments were performed for a thick turbulent boundary layer over a neutral or heated surface. Surface pressure and velocity probe measurements were acquired simultaneously. Two field deployments yielded surface pressure data from a 49 element array. The second deployment at the Reese Technology Center in Lubbock, TX, also included data from a smaller aperture, 96-element array and a 200-meter tall meteorological tower. Analysis of the data successfully demonstrated the ability to estimate the vertical velocity profile using coherence data from the pressure array. Also, dynamical systems analysis methods were successful in identifying and tracking a gust type event. In addition to the passive acoustic profiling method, this program also investigated a rapid response Doppler SODAR system, the optimization of wind turbine blades for enhanced power with reduced aeroacoustic noise production, and the implementation of a wireless health monitoring system for the wind turbine blades. Each of these other objectives was met successfully. The use of phase unwrapping applied to SODAR data was found to yield reasonable results for per-pulse measurements. A health monitoring system design analysis was able to demonstrate the ability to use a very small number of sensors to monitor blade health based on the blade's overall structural modes. Most notable was the development of a multi-objective optimization methodology that successfully yielded an aerodynamic blade design that produces greater power output with reduced aerodynamic loading noise. This optimization method could be significant for future design work.

  20. Plasma transferred arc repair welding of the nickel-base superalloy IN-738LC

    SciTech Connect (OSTI)

    Su, C.Y.; Chou, C.P. [National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Dept. of Mechanical Engineering; Wu, B.C.; Lih, W.C. [Industrial Technology Research Inst., Hsinchu (Taiwan, Province of China). Materials Research Labs.

    1997-10-01T23:59:59.000Z

    Plasma transferred arc welding (PTA) has been considered a promising process to restore worn areas of land-based gas turbine blades and vanes. The objective of this investigation was to study the effect of PTA welding on the repairing of IN-738LC superalloy components. Tensile tests were conducted on specimens welded with various combinations of parameters. Room temperature, 760 C, and 980 C were selected as tensile test temperatures. High-temperature phase transformed, during solidification, were identified by differential thermal analysis (DTA). The weld-pool shapes and microstructures of welded specimens prepared by various welding parameters were evaluated by optical metallography (OM), a scanning electron microscope (SEM) equipped with energy dispersive x-ray spectrometer (EDS), and microhardness testing. Results of this study showed that PTA welded specimens exhibited 96% nominal tensile strength of IN-738LC base materials. Specimen failure was observed predominantly in the base materials instead of in the heat-affected zone (HAZ) for gas tungsten arc weld (GTAW) repair weldments. IN-738LC is considered susceptible to weld cracking during fusion welding; however, using a low-input repair welding process (PTA), cracking susceptibility could be minimized by the optimized welding parameters.

  1. Robust optimization of a 2D air conditioning duct using kriging Deliverable WP.2.2.2.B of the ANR / OMD2 project

    E-Print Network [OSTI]

    Boyer, Edmond

    Robust optimization of a 2D air conditioning duct using kriging Deliverable WP.2.2.2.B of the ANR optimization of a 2D air conditioning duct. For comparison purposes, deterministic designs were first obtained air conditioning duct. The uncertainties affect the pipe shape. The mean response, expressed in terms

  2. DC arc weld starter

    DOE Patents [OSTI]

    Campiotti, Richard H. (Tracy, CA); Hopwood, James E. (Oakley, CA)

    1990-01-01T23:59:59.000Z

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  3. MAIN APPLICATIONS Spot welding

    E-Print Network [OSTI]

    De Luca, Alessandro

    IRB 6400 MAIN APPLICATIONS Spot welding Press tending Material handling Machine tending Palletizing N Poke welding All IRB 6400R-versions have Foundry Plus protection. For details, see under manipulator 6400PE 1600 kg Others 2060 - 2390 kg ENVIRONMENT Ambient temperature Manipulator 5 50C Relative

  4. Optimal Deployment of Thermal Energy Storage under Diverse Economic and Climate Conditions

    E-Print Network [OSTI]

    DeForest, Nicolas

    2014-01-01T23:59:59.000Z

    Sailor D, Palova AA. Air conditioning market saturation andof the developed world, air-conditioning in buildings is theincreasing utilization of air-conditioning places additional

  5. Method for welding beryllium

    DOE Patents [OSTI]

    Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

    1997-04-01T23:59:59.000Z

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

  6. Weld Results SUNY Stony Brook

    E-Print Network [OSTI]

    McDonald, Kirk

    Weld Results Yan Zhan SUNY Stony Brook June 13rd, 2013 1 #12;Outline Studied Parameters Results Analysis Contours Plots For the Weld Region Axial Velocity Profile at Different Locations Near the Weld Plots of Turbulent Kinetic Energy and Momentum Thickness Near the Weld Line Plot Goes From Inlet

  7. Modeling the field of laser welding melt pool by RBFNN

    E-Print Network [OSTI]

    Bracic, A Borstnik; Grabec, I

    2007-01-01T23:59:59.000Z

    Efficient control of a laser welding process requires the reliable prediction of process behavior. A statistical method of field modeling, based on normalized RBFNN, can be successfully used to predict the spatiotemporal dynamics of surface optical activity in the laser welding process. In this article we demonstrate how to optimize RBFNN to maximize prediction quality. Special attention is paid to the structure of sample vectors, which represent the bridge between the field distributions in the past and future.

  8. Prediction of Burr Formation during Face Milling Using an Artificial Neural Network with Optimized Cutting Conditions

    E-Print Network [OSTI]

    Lee, S H; Dornfeld, D A

    2007-01-01T23:59:59.000Z

    Appli- cation of artificial neural network in laser weldingwith minimal heights. Artificial neural network and non-milling using an artificial neural network with optimized

  9. Use of Aria to simulate laser weld pool dynamics for neutron generator production.

    SciTech Connect (OSTI)

    Noble, David R.; Notz, Patrick K.; Martinez, Mario J.; Kraynik, Andrew Michael

    2007-09-01T23:59:59.000Z

    This report documents the results for the FY07 ASC Integrated Codes Level 2 Milestone number 2354. The description for this milestone is, 'Demonstrate level set free surface tracking capabilities in ARIA to simulate the dynamics of the formation and time evolution of a weld pool in laser welding applications for neutron generator production'. The specialized boundary conditions and material properties for the laser welding application were implemented and verified by comparison with existing, two-dimensional applications. Analyses of stationary spot welds and traveling line welds were performed and the accuracy of the three-dimensional (3D) level set algorithm is assessed by comparison with 3D moving mesh calculations.

  10. WELDING RESEARCH -s55WELDING JOURNAL

    E-Print Network [OSTI]

    DuPont, John N.

    . This region was followed by a dual-phase austenite/martensite region near the in- terface between the grade steels and stainless steels still occur in many in- dustrial applications. These failures have generally between the carbon steel and stainless steel end members to permit the deposition of two similar welds

  11. Friction stir welding tool

    DOE Patents [OSTI]

    Tolle, Charles R. (Idaho Falls, ID); Clark, Denis E. (Idaho Falls, ID); Barnes, Timothy A. (Ammon, ID)

    2008-04-15T23:59:59.000Z

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  12. Monte Carlo study for optimal conditions in single-shot imaging with femtosecond x-ray laser pulses

    SciTech Connect (OSTI)

    Park, Jaehyun; Ishikawa, Tetsuya; Song, Changyong [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Joti, Yasumasa [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2013-12-23T23:59:59.000Z

    Intense x-ray pulses from x-ray free electron lasers (XFELs) enable the unveiling of atomic structure in material and biological specimens via ultrafast single-shot exposures. As the radiation is intense enough to destroy the sample, a new sample must be provided for each x-ray pulse. These single-particle delivery schemes require careful optimization, though systematic study to find such optimal conditions is still lacking. We have investigated two major single-particle delivery methods: particle injection as flying objects and membrane-mount as fixed targets. The optimal experimental parameters were searched for via Monte Carlo simulations to discover that the maximum single-particle hit rate achievable is close to 40%.

  13. Concurrent ultrasonic weld evaluation system

    DOE Patents [OSTI]

    Hood, D.W.; Johnson, J.A.; Smartt, H.B.

    1987-12-15T23:59:59.000Z

    A system for concurrent, non-destructive evaluation of partially completed welds for use in conjunction with an automated welder is disclosed. The system utilizes real time, automated ultrasonic inspection of a welding operation as the welds are being made by providing a transducer which follows a short distance behind the welding head. Reflected ultrasonic signals are analyzed utilizing computer based digital pattern recognition techniques to discriminate between good and flawed welds on a pass by pass basis. The system also distinguishes between types of weld flaws. 5 figs.

  14. Concurrent ultrasonic weld evaluation system

    DOE Patents [OSTI]

    Hood, D.W.; Johnson, J.A.; Smartt, H.B.

    1985-09-04T23:59:59.000Z

    A system for concurrent, non-destructive evaluation of partially completed welds for use in conjunction with an automated welder. The system utilizes real time, automated ultrasonic inspection of a welding operation as the welds are being made by providing a transducer which follows a short distance behind the welding head. Reflected ultrasonic signals are analyzed utilizing computer based digital pattern recognition techniques to discriminate between good and flawed welds on a pass by pass basis. The system also distinguishes between types of weld flaws.

  15. Optimization of the Fin Heat Pipe for Ventilating and Air Conditioning with a Genetic Algorithm

    E-Print Network [OSTI]

    Qian, J.; Sun, D.; Li, G.

    2006-01-01T23:59:59.000Z

    This paper illustrates that use of a heat pipe as a heat-reclaiming device can significantly influence the air-conditioning system. It analyzes the heat transfer model of the uniform annular fin heat pipe under the condition of air conditioning...

  16. Optimization of the Fin Heat Pipe for Ventilating and Air Conditioning with a Genetic Algorithm

    E-Print Network [OSTI]

    Qian, J.; Sun, D.; Li, G.

    2006-01-01T23:59:59.000Z

    This paper illustrates that use of a heat pipe as a heat-reclaiming device can significantly influence the air-conditioning system. It analyzes the heat transfer model of the uniform annular fin heat pipe under the condition of air conditioning...

  17. Certification of a weld produced by friction stir welding

    DOE Patents [OSTI]

    Obaditch, Chris; Grant, Glenn J

    2013-10-01T23:59:59.000Z

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  18. Optimal operating conditions and configurations for humidification-dehumidification desalination cycles

    E-Print Network [OSTI]

    Lienhard V, John H.

    , each with either an air or a water heater, were considered in this analysis. Numerical optimization distillate) [kJ/kg] L length of heater [m] m mass flow rate [kg/s] mr mass flow rate ratio (feed water to dry that result in maximum gained output ratio (GOR). Closed air open water as well as open air open water cycles

  19. Robotic Welding and Inspection System

    SciTech Connect (OSTI)

    H. B. Smartt; D. P. Pace; E. D. Larsen; T. R. McJunkin; C. I. Nichol; D. E. Clark; K. L. Skinner; M. L. Clark; T. G. Kaser; C. R. Tolle

    2008-06-01T23:59:59.000Z

    This paper presents a robotic system for GTA welding of lids on cylindrical vessels. The system consists of an articulated robot arm, a rotating positioner, end effectors for welding, grinding, ultrasonic and eddy current inspection. Features include weld viewing cameras, modular software, and text-based procedural files for process and motion trajectories.

  20. Final Report: A Transport Phenomena Based Approach to Probe Evolution of Weld Macro and Microstructures and A Smart Bi-directional Model of Fusion Welding

    SciTech Connect (OSTI)

    Dr. Tarasankar DebRoy

    2009-12-11T23:59:59.000Z

    In recent years, applications of numerical heat transfer and fluid flow models of fusion welding have resulted in improved understanding of both the welding processes and welded materials. They have been used to accurately calculate thermal cycles and fusion zone geometry in many cases. Here we report the following three major advancements from this project. First, we show how microstructures, grain size distribution and topology of welds of several important engineering alloys can be computed starting from better understanding of the fusion welding process through numerical heat transfer and fluid flow calculations. Second, we provide a conclusive proof that the reliability of numerical heat transfer and fluid flow calculations can be significantly improved by optimizing several uncertain model parameters. Third, we demonstrate how the numerical heat transfer and fluid flow models can be combined with a suitable global optimization program such as a genetic algorithm for the tailoring of weld attributes such as attaining a specified weld geometry or a weld thermal cycle. The results of the project have been published in many papers and a listing of these are included together with a list of the graduate thesis that resulted from this project. The work supported by the DOE award has resulted in several important national and international awards. A listing of these awards and the status of the graduate students are also presented in this report.

  1. Friction stir welding tool and process for welding dissimilar materials

    DOE Patents [OSTI]

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07T23:59:59.000Z

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  2. Welding for testability: An approach aimed at improving the ultrasonic testing of thick-walled austenitic and dissimilar metal welds

    SciTech Connect (OSTI)

    Wagner, Sabine; Dugan, Sandra [Materials Testing Institute University of Stuttgart (MPA), Pfaffenwaldring 32, 70569 Stuttgart (Germany); Barth, Martin; Schubert, Frank; Khler, Bernd [Fraunhofer Institute for Nondestructive Testing, Dresden Branch (IZFP-D), Maria-Reiche-Str. 2, 01109 Dresden (Germany)

    2014-02-18T23:59:59.000Z

    Austenitic and dissimilar welds in thick walled components show a coarse grained, dendritic microstructure. Therefore, ultrasonic testing has to deal with beam refraction, scattering and mode conversion effects. As a result, the testing techniques typically applied for isotropic materials yield dissatisfying results. Most approaches for improvement of ultrasonic testing have been based on modeling and improved knowledge of the complex wave propagation phenomena. In this paper, we discuss an alternative approach: is it possible to use a modified welding technology which eliminates the cause of the UT complications, i.e. the large-grained structure of the weld seams? Various modification parameters were tested, including: TIG current pulsing, additional DC and AC magnetic fields, and also additional external vibrations during welding. For all welds produced under different conditions, the grain structure of the weld seam was characterized by optical and GIUM microstructure visualizations on cross sections, wave field propagation measurements, and ultrasonic tests of correct detectability of flaws. The mechanical properties of the welds were also tested.

  3. Method and apparatus for assessing weld quality

    DOE Patents [OSTI]

    Smartt, Herschel B. (Idaho Falls, ID); Kenney, Kevin L. (Idaho Falls, ID); Johnson, John A. (Idaho Falls, ID); Carlson, Nancy M. (Idaho Falls, ID); Clark, Denis E. (Idaho Falls, ID); Taylor, Paul L. (Boise, ID); Reutzel, Edward W. (State College, PA)

    2001-01-01T23:59:59.000Z

    Apparatus for determining a quality of a weld produced by a welding device according to the present invention includes a sensor operatively associated with the welding device. The sensor is responsive to at least one welding process parameter during a welding process and produces a welding process parameter signal that relates to the at least one welding process parameter. A computer connected to the sensor is responsive to the welding process parameter signal produced by the sensor. A user interface operatively associated with the computer allows a user to select a desired welding process. The computer processes the welding process parameter signal produced by the sensor in accordance with one of a constant voltage algorithm, a short duration weld algorithm or a pulsed current analysis module depending on the desired welding process selected by the user. The computer produces output data indicative of the quality of the weld.

  4. WELDING RESEARCH ~~--------------~~~ SUPPLEMENT TO THE WELDING JOURNAL, MAY 1990

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) WELDING RESEARCH ~~--------------~~~ SUPPLEMENT TO THE WELDING JOURNAL, MAY 1990 Sponsored by the American Welding Society and the Welding Research Council All papers published in the Welding Journal's Welding Research Supplement undergo Peer Review before publication for: 1) originality of the contribution

  5. Masatsu kakuhan setsugo "Friction Stir Welding Complete aspects of FSW" Japan Welding Society

    E-Print Network [OSTI]

    Cambridge, University of

    Masatsu kakuhan setsugo "Friction Stir Welding Complete aspects of FSW" Japan Welding Society years ago that the Friction Stir Welding (FSW) method was proposed by TWI. Because FSW is a solid state welding method, the peak temperature reached during FSW welding is lower than the traditional welding

  6. Method for welding chromium molybdenum steels

    DOE Patents [OSTI]

    Sikka, Vinod K. (Clinton, TN)

    1986-01-01T23:59:59.000Z

    Chromium-molybdenum steels exhibit a weakening after welding in an area adjacent to the weld. This invention is an improved method for welding to eliminate the weakness by subjecting normalized steel to a partial temper prior to welding and subsequently fully tempering the welded article for optimum strength and ductility.

  7. Toolbox Safety Talk Welding & Metal Work Safety

    E-Print Network [OSTI]

    Pawlowski, Wojtek

    Toolbox Safety Talk Welding & Metal Work Safety Environmental Health & Safety Facilities Safety or harmful emission giving metals. Welding Safety When welding outside of a designated welding booth, ensure injury. Avoid welding on materials such as galvanized or stainless steel in order to minimize toxic fume

  8. EFFECT OF MINOR ADDITIONS OF HYDROGEN TO ARGON SHIELDING GAS WHEN WELDING AUSTENITIC STAINLESS STEEL WITH THE GTAW PROCESS

    SciTech Connect (OSTI)

    CANNELL, G.R.

    2004-12-15T23:59:59.000Z

    This paper provides the technical basis to conclude that the use of hydrogen containing shielding gases during welding of austenitic stainless steels will not lead to hydrogen induced cracking (HIC) of the weld or weld heat affected zone. Argon-hydrogen gas mixtures, with hydrogen additions up to 35% [1], have been successfully used as the shielding gas in gas tungsten arc welding (GTAW) of austenitic stainless steels. The addition of hydrogen improves weld pool wettability, bead shape control, surface cleanliness and heat input. The GTAW process is used extensively for welding various grades of stainless steel and is preferred when a very high weld quality is desired, such as that required for closure welding of nuclear materials packages. The use of argon-hydrogen gas mixtures for high-quality welding is occasionally questioned, primarily because of concern over the potential for HIC. This paper was written specifically to provide a technical basis for using an argon-hydrogen shielding gas in conjunction with the development, at the Savannah River Technology Center (SRTC), of an ''optimized'' closure welding process for the DOE standardized spent nuclear fuel canister [2]. However, the basis developed here can be applied to other applications in which the use of an argon-hydrogen shielding gas for GTAW welding of austenitic stainless steels is desired.

  9. On the development of nugget growth model for resistance spot welding

    SciTech Connect (OSTI)

    Zhou, Kang, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk; Cai, Lilong, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk [Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2014-04-28T23:59:59.000Z

    In this paper, we developed a general mathematical model to estimate the nugget growth process based on the heat energy delivered into the welds by the resistance spot welding. According to the principles of thermodynamics and heat transfer, and the effect of electrode force during the welding process, the shape of the nugget can be estimated. Then, a mathematical model between heat energy absorbed and nugget diameter can be obtained theoretically. It is shown in this paper that the nugget diameter can be precisely described by piecewise fractal polynomial functions. Experiments were conducted with different welding operation conditions, such as welding currents, workpiece thickness, and widths, to validate the model and the theoretical analysis. All the experiments confirmed that the proposed model can predict the nugget diameters with high accuracy based on the input heat energy to the welds.

  10. Shell Hoop Prestress Generated by Welding

    E-Print Network [OSTI]

    Meuser, R.B.

    2011-01-01T23:59:59.000Z

    can be generated by the welding process. The data are notagainst the yoke for welding. TEST SETUP Annealed Type 304in two passes using TIG welding. After strain measurements

  11. Overlay welding irradiated stainless steel

    SciTech Connect (OSTI)

    Kanne, W.R.; Chandler, G.T.; Nelson, D.Z.; Franco-Ferreira, E.A.

    1993-08-01T23:59:59.000Z

    An overlay technique developed for welding irradiated stainless steel may be important for repair or modification of fusion reactor materials. Helium, present due to n,{alpha} reactions, is known to cause cracking using conventional welding methods. Stainless steel impregnated with 3 to 220 appm helium by decay of tritium was used to develop a welding process that could be used for repair. The result was a gas metal arc weld overlay technique with low-heat input and low-penetration into the helium-containing material. Extensive metallurgical and mechanical testing of this technique demonstrated substantial reduction of helium embrittlement damage. The overlay technique was applied to irradiated 304 stainless steel containing 10 appm helium. Surface cracking, present in conventional welds made on the same steel at lower helium concentrations, was eliminated. Underbead cracking, although greater than for tritium charged and aged material, was minimal compared to conventional welding methods.

  12. Integration of Low Energy Technologies for Optimal Building and Space Conditioning Design

    SciTech Connect (OSTI)

    D.E. Fisher

    2006-01-07T23:59:59.000Z

    EnergyPlus is the DOE's newest building energy simulation engine. It was developed specifically to support the design of low energy building systems. This project focused on developing new low energy building simulation models for EnergyPlus, verifying and validating new and existing EnergyPlus models and transferring the new technology to the private sector. The project focused primarily on geothermal and radiant technologies, which are related by the fact that both are based on hydronic system design. As a result of this project eight peer reviewed journal and conference papers were added to the archival literature and five technical reports were published as M.S. theses and are available in the archival literature. In addition, several reports, including a trombe wall validation report were written for web publication. Thirteen new or significantly enhanced modules were added to the EnergyPlus source code and forty-two new or significantly enhanced sections were added to the EnergyPlus documentation as a result of this work. A low energy design guide was also developed as a pedagogical tool and is available for web publication. Finally several tools including a hybrid ground source heat pump optimization program and a geothermal heat pump parameter estimation tool were developed for research and design and are available for web publication.

  13. The Impact of Global Warming on U.S. Agriculture: An Econometric Analysis of Optimal Growing Conditions

    E-Print Network [OSTI]

    Schlenker, Wolfram; Hanemann, W. Michael; Fisher, Anthony C.

    2004-01-01T23:59:59.000Z

    U.S. Agriculture: An Econometric Analysis of Optimal GrowingU.S. Agriculture: An Econometric Analysis of Optimal GrowingU.S. Agriculture: An Econometric Analysis of Optimal Growing

  14. Welding tritium aged stainless steel

    SciTech Connect (OSTI)

    Kanne, W.R. Jr.

    1993-04-01T23:59:59.000Z

    Stainless steels exposed to tritium become unweldable by conventional methods due to He buildup within the metal matrix. With longer service lives expected for new weapon systems, and service life extensions of older systems, methods for welding/repair on tritium-exposed material will become important. Results are reported that indicate that both solid-state resistance welding and low-heat gas metal arc overlay welding are promising methods for repair or modification of tritium-aged stainless steel.

  15. Weld overlay cladding with iron aluminides

    SciTech Connect (OSTI)

    Goodwin, G.M.

    1996-11-01T23:59:59.000Z

    The hot and cold cracking tendencies of some early iron aluminide alloy compositions limited their use to applications where good weldability was not required. Considerable progress has been made toward improving this situation. Using hot crack testing techniques developed at ORNL and a systematic study of alloy compositional effects, we have established a range of compositions within which hot cracking resistance is very good, essentially equivalent to stainless steel. Cold cracking, however, remains an issue, and extensive efforts are continuing to optimize composition and welding parameters, especially preheat and postweld heat treatment, to minimize its occurrence. In terms of filler metal and process development, we have progressed from sheared strip through aspiration cast rod and shielded metal arc electrodes to the point where we can now produce composite wire with a steel sheath and aluminum core in coil form, which permits the use of both the gas tungsten arc and gas metal arc processes. This is a significant advancement in that the gas metal arc process lends itself well to automated welding, and is the process of choice for commercial weld overlay applications. Using the newly developed filler metals, we have prepared clad specimens for testing in a variety of environments both in-house and outside ORNL, including laboratory and commercial organizations. As a means of assessing the field performance of this new type of material, we have modified several non-pressure boundary boiler components, including fuel nozzles and port shrouds, by introducing areas of weld overlay in strategic locations, and have placed these components in service in operating boilers for a side-by-side comparison with conventional corrosion-resistant materials.

  16. Specification and qualification of welding procedures for metallic materials : Welding procedure test : Part 2: Arc welding of aluminium and its alloys

    E-Print Network [OSTI]

    International Organization for Standardization. Geneva

    2005-01-01T23:59:59.000Z

    Specification and qualification of welding procedures for metallic materials : Welding procedure test : Part 2: Arc welding of aluminium and its alloys

  17. Specification and qualification of welding procedures for metallic materials : Welding procedure test : Part 2: Arc welding of aluminium and its alloys : technical corrigendum 1

    E-Print Network [OSTI]

    International Organization for Standardization. Geneva

    2005-01-01T23:59:59.000Z

    Specification and qualification of welding procedures for metallic materials : Welding procedure test : Part 2: Arc welding of aluminium and its alloys : technical corrigendum 1

  18. Assessment of Weld Overlays for Mitigating Primary Water Stress Corrosion Cracking at Nickel Alloy Butt Welds in Piping Systems Approved for Leak-Before-Break

    SciTech Connect (OSTI)

    Sullivan, Edward J.; Anderson, Michael T.

    2012-08-01T23:59:59.000Z

    This TLR provides an assessment of weld overlays as a mitigation strategy for PWSCC, and includes an assessment of the WOL-related inspection requirements of Code Case N-770-1, as conditioned in 50.55a.

  19. Weld solidification cracking in 304 to 204L stainless steel

    SciTech Connect (OSTI)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-09-15T23:59:59.000Z

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found.This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GTAW showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  20. Weld solidification cracking in 304 to 304L stainless steel

    SciTech Connect (OSTI)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Martinez, Raymond J [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found. This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GT A W showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  1. Joint strength in high speed friction stir spot welded DP 980 steel

    SciTech Connect (OSTI)

    Saunders, Nathan; Miles, Michael; Hartman, Trent; Hovanski, Yuri; Hong, Sung Tae; Steel, Russell

    2014-05-01T23:59:59.000Z

    High speed friction stir spot welding was applied to 1.2 mm thick DP 980 steel sheets under different welding conditions, using PCBN tools. The range of vertical feed rates used during welding was 2.5 mm 102 mm per minute, while the range of spindle speeds was 2500 6000 rpm. Extended testing was carried out for five different sets of welding conditions, until tool failure. These welding conditions resulted in vertical welding loads of 3.6 8.2 kN and lap shear tension failure loads of 8.9 11.1 kN. PCBN tools were shown, in the best case, to provide lap shear tension fracture loads at or above 9 kN for 900 spot welds, after which tool failure caused a rapid drop in joint strength. Joint strength was shown to be strongly correlated to bond area, which was measured from weld cross sections. Failure modes of the tested joints were a function of bond area and softening that occurred in the heat-affected zone.

  2. Hybrid laser welding techniques for enhanced welding efficiency

    SciTech Connect (OSTI)

    Beyer, E.; Poprawe, R. [Fraunhofer-Institut fuer Lasertechnik (ILT), Aachen (Germany); Brenner, B. [Fraunhofer-Institut fuer Werkstoffphysik und Schichttechnologie (IWS), Dresden (Germany)

    1996-12-31T23:59:59.000Z

    One of the remarkable characteristics of the laser beam welding process is its thin deep welding seam. This thin seam is produced as a result of the high welding speed and the low heat input, leading to a low distortion. However, the overall electrical efficiency of a CO{sub 2}-laser is in the range of 5-7% and the efficiency of a Nd:YAG-laser is only approximately 2-3%. There are several applications in which the thin laser seam and the high welding speed, in particular, have technical advantages, making the whole process economical. However, there are also a lot of possible applications, for which laser welding is too expensive at the moment or, in which the thin seam leads to a lot of unsolved metallurgical problems. To avoid these problems, a welding technique is presently being developed at the ILT and IWS which combines laser keyhole welding with Tungsten inert gas and metal inert gas welding and introduces an inductor for a preheating and a controlled heat flow. The paper is divided into two sections. The first section describes recent investigations carried out by the ILT into the laser arc combination and the second section describes the combination of the laser and induction techniques, presenting also an application presently being used in production in the car industry. This work has been completed by the Fraunhofer-Institut fur Werkstoffphysik und Schichttechnologie IWS in Dresden.

  3. Narrow groove welding gas diffuser assembly and welding torch

    DOE Patents [OSTI]

    Rooney, Stephen J. (East Berne, NY)

    2001-01-01T23:59:59.000Z

    A diffuser assembly is provided for narrow groove welding using an automatic gas tungsten arc welding torch. The diffuser assembly includes a manifold adapted for adjustable mounting on the welding torch which is received in a central opening in the manifold. Laterally extending manifold sections communicate with a shield gas inlet such that shield gas supplied to the inlet passes to gas passages of the manifold sections. First and second tapered diffusers are respectively connected to the manifold sections in fluid communication with the gas passages thereof. The diffusers extend downwardly along the torch electrode on opposite sides thereof so as to release shield gas along the length of the electrode and at the distal tip of the electrode. The diffusers are of a transverse width which is on the order of the thickness of the electrode so that the diffusers can, in use, be inserted into a narrow welding groove before and after the electrode in the direction of the weld operation.

  4. Friction Stir Welding Of Ma957 Oxide Dispersion Strengthened Ferritic Steel

    SciTech Connect (OSTI)

    Howard, Stanley M.; Jasthi, Bharat K.; Arbegast, William J.; Grant, Glenn J.; Koduri, Santhosh K.; Herling, Darrell R.; Gelles, David S.

    2005-04-02T23:59:59.000Z

    A 1-in. (25.4 mm) diameter yttria-dispersion-strengthened MA957 ferritic steel alloy tube with a 0.125" (3.18 mm) wall thickness was successfully plasticized by friction stir welding. The pin tool was a W-Re tool with 0.125" (3.17 mm) diameter tip. It showed no discernable wear for the total 12" (305 mm) of weld. Weld conditions were 1000 and 1400 RPM, 4 in/min (101 mm/min), with and without preheating to 135C. Metallographic analysis of the post friction-stir welded material showed a decrease in material hardness to 22522 HV compared to the parent material at 37321 HV. All weld conditions produced plasticization; however, improved plasticization was observed for preheated samples

  5. Effect of multiple repairs in girth welds of pipelines on the mechanical properties

    SciTech Connect (OSTI)

    Vega, O.E.; Hallen, J.M. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, Laboratorios Pesados de Metalurgia, UPALM, Zacatenco, C.P. 07738, Mexico D.F. (Mexico); Villagomez, A. [Construcciones Maritimas Mexicanas, CMM-PROTEXA, Av. Periferica s/n, Fracc. Lomas de Holche, C.P. 24120, Cd. del Carmen, Campeche (Mexico); Contreras, A. [Instituto Mexicano del Petroleo, Investigacion en Ductos, Corrosion y Materiales, Eje Central Lazaro Cardenas Norte 152 Col. San Bartolo Atepehuacan, C.P. 07730, Mexico D.F. (Mexico)], E-mail: acontrer@imp.mx

    2008-10-15T23:59:59.000Z

    This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases.

  6. Resistance Spot Welding of Galvanized Steel: Part II. Mechanisms of Spot Weld Nugget Formation

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ( l Resistance Spot Welding of Galvanized Steel: Part II. Mechanisms of Spot Weld Nugget Formation S. A. GEDEON and T. W. EAGAR Dynamic inspection monitoring of the weld current, voltage, resistance of material variations and weld process parameter modifications on resistance spot welding of coated

  7. Developing a dissimilar metal foil-to-substrate resistance welding process.

    SciTech Connect (OSTI)

    Knorovsky, Gerald Albert

    2010-10-01T23:59:59.000Z

    Materials changes occurring upon redesign caused redevelopment of the multiple spot resistance weld procedure employed to join a 23 micrometer thick foil of 15-7PH to a thick substrate and (at a separate location) a second, smaller thermal mass substrate. Both substrates were 304L. To avoid foil wrinkling, minimal heat input was used. The foil/thick substrate weld was solid-state, though the foil/small substrate weld was not. Metallographic evidence indicated occasional separation of the solid-state weld, hence a fusion weld was desired at both locations. In the redesign, a Co-Cr-Fe-Ni alloy was substituted for the foil, and a Ni-Cr-Mo alloy was evaluated for the small substrate. Both materials are substantially more resistive than their predecessors. This study reports development of weld schedules to accommodate the changes, yet achieve the fusion weld goal. Thermal analysis was employed to understand the effects caused by the various weld schedule parameters, and guide their optimization.

  8. SOAR: Smartweld optimization and analysis routines

    SciTech Connect (OSTI)

    Eisler, G.R.; Fuerschbach, P.W.

    1996-10-01T23:59:59.000Z

    A suite of MATLAB-based code modules has been developed to provide optimal weld schedules, regulating weld process parameters for C0[sub 2] and pulse ND:YAG laser welding methods, and arc welding in support of the Smartweld manufacturing initiative. The optimization methodology consists of mixed genetic and gradient-based algorithms to query semi-empirical, nonlinear algebraic models. The optimization output provides heat-input-efficient welds for user-specified weld dimensions. User querying of all weld models is available to examine sub-optimal schedules. In addition, a heat conduction equation solver for 2-D heat flow is available to provide the user with an additional check of weld thermal effects. The inclusion of thermodynamic properties allows the extension of the empirical models to include materials other than those tested. All solution methods are provided with graphical user interfaces and display pertinent results in two and three-dimensional form. The code architecture provides an extensible framework to add an arbitrary number of modules.

  9. Improving approximate-optimized effective potentials by imposing exact conditions: Theory and applications to electronic statics and dynamics

    SciTech Connect (OSTI)

    Kurzweil, Yair; Head-Gordon, Martin [Department of Chemistry, University of California at Berkeley, Berkeley, California 94720 (United States) and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2009-07-15T23:59:59.000Z

    We develop a method that can constrain any local exchange-correlation potential to preserve basic exact conditions. Using the method of Lagrange multipliers, we calculate for each set of given Kohn-Sham orbitals a constraint-preserving potential which is closest to the given exchange-correlation potential. The method is applicable to both the time-dependent (TD) and independent cases. The exact conditions that are enforced for the time-independent case are Galilean covariance, zero net force and torque, and Levy-Perdew virial theorem. For the time-dependent case we enforce translational covariance, zero net force, Levy-Perdew virial theorem, and energy balance. We test our method on the exchange (only) Krieger-Li-Iafrate (xKLI) approximate-optimized effective potential for both cases. For the time-independent case, we calculated the ground state properties of some hydrogen chains and small sodium clusters for some constrained xKLI potentials and Hartree-Fock (HF) exchange. The results (total energy, Kohn-Sham eigenvalues, polarizability, and hyperpolarizability) indicate that enforcing the exact conditions is not important for these cases. On the other hand, in the time-dependent case, constraining both energy balance and zero net force yields improved results relative to TDHF calculations. We explored the electron dynamics in small sodium clusters driven by cw laser pulses. For each laser pulse we compared calculations from TD constrained xKLI, TD partially constrained xKLI, and TDHF. We found that electron dynamics such as electron ionization and moment of inertia dynamics for the constrained xKLI are most similar to the TDHF results. Also, energy conservation is better by at least one order of magnitude with respect to the unconstrained xKLI. We also discuss the problems that arise in satisfying constraints in the TD case with a non-cw driving force.

  10. WELDING AND CUTTING 10.A GENERAL

    E-Print Network [OSTI]

    US Army Corps of Engineers

    EM 385-1-1 XX Jun 13 10-1 SECTION 10 WELDING AND CUTTING 10.A GENERAL 10.A.01 Welders, cutters, and their supervisor shall be trained in the safe operation of their equipment, safe welding/cutting practices, and welding/cutting respiratory and fire protection. > AIHA publication "Welding Health and Safety: A Field

  11. Assessing Exposures to Particulate Matter and Manganese in Welding Fumes

    E-Print Network [OSTI]

    LIU, SA

    2010-01-01T23:59:59.000Z

    465. SappME. AHistoryofWelding:fromHepheastustowhistoryfolder/welding/index.html. SaricM,Markicevic,be retrieved from American Welding Society publications. The

  12. Method for controlling gas metal arc welding

    DOE Patents [OSTI]

    Smartt, Herschel B. (Idaho Falls, ID); Einerson, Carolyn J. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

    1989-01-01T23:59:59.000Z

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections.

  13. Method for controlling gas metal arc welding

    DOE Patents [OSTI]

    Smartt, H.B.; Einerson, C.J.; Watkins, A.D.

    1987-08-10T23:59:59.000Z

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections. 3 figs., 1 tab.

  14. Irradiation embrittlement modelling of Linde 80 weld metals

    SciTech Connect (OSTI)

    McElroy, R.J. [AEA Technology, Didcot (United Kingdom). Harwell Lab.; Lowe, A.L. Jr. [Lowe Associates, Lynchburg, VA (United States)

    1996-12-31T23:59:59.000Z

    Linde 80 weld metals are characterized by a narrow range of chemical compositions, except for copper content, which varies from 0.2--0.42 wt%. The surveillance database for Linde 80 weld metals constitutes a unique and large database on a single class of material for evaluating embrittlement models and property correlations used in the assessment of RPV embrittlement. The main purpose of the present study has been to obtain a simple two component barrier hardening model form which best describes the behavior of Linde 80 weld metal. To this end, the UK Magnox Embrittlement Model, often referred to as the Fisher Model, has been used and the key parameters, such as activation energies, dislocation densities and damage cross sections, were used as fitting parameters. Good agreement was found between model predictions and the surveillance yield strength data following optimization of model parameters. Applying the latter optimized form produced equally good prediction of HSSI results at a significantly higher damage rate demonstrating the rate effect inherent in the irradiation enhanced copper precipitation process. The best agreement was obtained assuming a matrix copper content of about 0.23 wt% which is consistent with recent solubility data for Linde 80 welds. For these materials an insensitivity to bulk copper content was demonstrated even though this varied from 0.21--0.42 wt%. Additionally, the parameters optimized for high copper welds provided a good prediction for low-copper materials indicating that the matrix hardening component was correctly specified. The low matrix hardening and predicted completion of copper precipitation by doses of about 1 {times} 10{sup 19} ncm{sup {minus}2} support the notion of embrittlement saturation at high doses.

  15. Control of Gas Tungsten Arc welding pool shape by trace element addition to the weld pool

    DOE Patents [OSTI]

    Heiple, C.R.; Burgardt, P.

    1984-03-13T23:59:59.000Z

    An improved process for Gas Tungsten Arc welding maximizes the depth/width ratio of the weld pool by adding a sufficient amount of a surface active element to insure inward fluid flow, resulting in deep, narrow welds. The process is especially useful to eliminate variable weld penetration and shape in GTA welding of steels and stainless steels, particularly by using a sulfur-doped weld wire in a cold wire feed technique.

  16. Optimization of the deposition and annealing conditions of fluorine-doped indium oxide films for silicon solar cells

    SciTech Connect (OSTI)

    Untila, G. G., E-mail: GUntila@mics.msu.su; Kost, T. N.; Chebotareva, A. B.; Timofeyev, M. A. [Moscow State University, Skobel'tsyn Institute of Nuclear Physics (Russian Federation)

    2013-03-15T23:59:59.000Z

    Fluorine-doped indium oxide (IFO) films are deposited onto (pp{sup +})Si and (n{sup +}nn{sup +})Si structures made of single-crystal silicon by ultrasonic spray pyrolysis. The effect of the IFO deposition time and annealing time in an argon atmosphere with methanol vapor on the IFO chemical composition, the photovoltage and fill factor of the Illumination-U{sub oc} curves of IFO/(pp{sup +})Si structures, and the sheet resistance of IFO/(n{sup +}nn{sup +})Si structures, correlating with the IFO/(n{sup +})Si contact resistance, is studied. The obtained features are explained by modification of the properties of the SiO{sub x} transition layer at the IFO/Si interface during deposition and annealing. Analysis of the results made it possible to optimize the fabrication conditions of solar cells based on IFO/(pp{sup +})Si heterostructures and to increase their efficiency from 17% to a record 17.8%.

  17. Influence of Alloy and Solidification Parameters on Grain Refinement in Aluminum Weld Metal due to Inoculation

    SciTech Connect (OSTI)

    Schempp, Philipp [BAM, Germany; Tang, Z. [BIAS, Germany; Cross, Carl E. [Los Alamos National Laboratory; Seefeld, T. [BIAS, Germany; Pittner, A. [BAM, Germany; Rethmeier, M. [BAM, Germany

    2012-06-28T23:59:59.000Z

    The goals are: (1) Establish how much Ti/B grain refiner is need to completely refine aluminum weld metal for different alloys and different welding conditions; (2) Characterize how alloy composition and solidification parameters affect weld metal grain refinement; and (3) Apply relevant theory to understand observed behavior. Conclusions are: (1) additions of Ti/B grain refiner to weld metal in Alloys 1050, 5083, and 6082 resulted in significant grain refinement; (2) grain refinement was more effective in GTAW than LBW, resulting in finer grains at lower Ti content - reason is limited time available for equiaxed grain growth in LBW (inability to occlude columnar grain growth); (3) welding travel speed did not markedly affect grain size within GTAW and LBW clusters; and (4) application of Hunt CET analysis showed experimental G to be on the order of the critical G{sub CET}; G{sub CET} was consistently higher for GTAW than for LBW.

  18. Three-dimensional modeling of the plasma arc in arc welding

    SciTech Connect (OSTI)

    Xu, G.; Tsai, H. L. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 1870 Miner Circle, Rolla, Missouri 65409 (United States); Hu, J. [Department of Mechanical Engineering, University of Bridgeport, Bridgeport, Connecticut 06604 (United States)

    2008-11-15T23:59:59.000Z

    Most previous three-dimensional modeling on gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool dynamics and assumes the two-dimensional axisymmetric Gaussian distributions for plasma arc pressure and heat flux. In this article, a three-dimensional plasma arc model is developed, and the distributions of velocity, pressure, temperature, current density, and magnetic field of the plasma arc are calculated by solving the conservation equations of mass, momentum, and energy, as well as part of the Maxwell's equations. This three-dimensional model can be used to study the nonaxisymmetric plasma arc caused by external perturbations such as an external magnetic field. It also provides more accurate boundary conditions when modeling the weld pool dynamics. The present work lays a foundation for true three-dimensional comprehensive modeling of GTAW and GMAW including the plasma arc, weld pool, and/or electrode.

  19. A two-dimensional thermomechanical simulation of a gas metal arc welding process

    SciTech Connect (OSTI)

    Ortega, A.R.

    1990-08-01T23:59:59.000Z

    A low heat input gas metal arc (GMA) weld overlay process is being investigated as a possible means to repair Savannah River nuclear reactor tanks in the event cracks are detected in the reactor walls. Two-dimensional thermomechanical simulations of a GMA welding process were performed using the finite element code ABAQUS to assist in the design of the upcoming weld experiments on helium-charged specimens. The thermal model correlated well with existing test data, i.e., fusion zone depth and thermocouple data. In addition, numerical results revealed that after cool-down the final deformation of the workpiece was qualitatively similar to the shape observed experimentally. Based on these analyses, conservative recommendations were made for the workpiece dimensions, weld pass spacing, and thermomechanical boundary conditions to ensure the experiments would be as representative as possible of welding on the reactor walls. 12 refs., 13 figs.

  20. Pulse shaping effects on weld porosity in laser beam spot welds : contrast of long- & short- pulse welds.

    SciTech Connect (OSTI)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew J. (R.J. Lee Group, Inc., Monroeville, PA); Faraone, Kevin M. (BWX Technologies, Inc., Lynchburg, VA); Norris, Jerome T.

    2007-10-01T23:59:59.000Z

    Weld porosity is being investigated for long-pulse spot welds produced by high power continuous output lasers. Short-pulse spot welds (made with a pulsed laser system) are also being studied but to a much small extent. Given that weld area of a spot weld is commensurate with weld strength, the loss of weld area due to an undefined or unexpected pore results in undefined or unexpected loss in strength. For this reason, a better understanding of spot weld porosity is sought. Long-pulse spot welds are defined and limited by the slow shutter speed of most high output power continuous lasers. Continuous lasers typically ramp up to a simmer power before reaching the high power needed to produce the desired weld. A post-pulse ramp down time is usually present as well. The result is a pulse length tenths of a second long as oppose to the typical millisecond regime of the short-pulse pulsed laser. This study will employ a Lumonics JK802 Nd:YAG laser with Super Modulation pulse shaping capability and a Lasag SLS C16 40 W pulsed Nd:YAG laser. Pulse shaping will include square wave modulation of various peak powers for long-pulse welds and square (or top hat) and constant ramp down pulses for short-pulse welds. Characterization of weld porosity will be performed for both pulse welding methods.

  1. Thin plate gap bridging study for Nd:YAG pulsed laser lap welds.

    SciTech Connect (OSTI)

    Roach, Robert Allen; Fuerschbach, Phillip William; Bernal, John E.; Norris, Jerome T.

    2006-01-01T23:59:59.000Z

    In an on going study of gap bridging for thin plate Nd:YAG laser lap welds, empirical data, high speed imaging, and computer modeling were utilized to better understand surface physics attributed to the formation and solidification of a weld pool. Experimental data indicates better gap bridging can be achieved through optimized laser parameters such as pulse length, duration, and energy. Long pulse durations at low energies generating low peak powers were found to create the highest percent of gap bridging ability. At constant peak power, gap-bridging ability was further improved by using a smaller spot diameter resulting in higher irradiances. Hence, welding in focus is preferable for bridging gaps. Gas shielding was also found to greatly impact gap-bridging ability. Gapped lap welds that could not be bridged with UHP Argon gas shielding, were easily bridged when left unshielded and exposed to only air. Incident weld angle and joint offset were also investigated for their ability to improve gap bridging. Optical filters and brightlight surface illumination enabled high-speed imaging to capture the fluid dynamics of a forming and solidifying weld pool. The effects of various laser parameters and the weld pool's interaction with the laser beam could also be observed utilizing the high-speed imaging. The work described is used to develop and validate a computer model with improved weld pool physics. Finite element models have been used to derive insight into the physics of gap bridging. The dynamics of the fluid motion within the weld pool in conjunction with the free surface physics have been the primary focus of the modeling efforts. Surface tension has been found to be a more significant factor in determining final weld pool shape than expected.

  2. A calorimetric-based comparison of gas tungsten and plasma arc welding processes

    SciTech Connect (OSTI)

    Knorovsky, G.A.; Fuerschbach, P.W.

    1988-01-01T23:59:59.000Z

    Measurements of arc and melting efficiencies have been made for pulsed and continuous mode Gas Tungsten Arc Welding (GTAW) and Plasma Arc Welding (PAW) processes. Welds were made on 2.5 mm total thickness pure Ni and 304 Stainless Steel in a standing edge weld geometry at constant nominal machine output settings which varied average current with travel speed. Under continuous current conditions, the measured heat input remained approximately constant for the conditions examined (250-1250 mm/min), while melting efficiency increased dramatically (0-/approximately/0.4). Arc efficiencies were relatively constant, remaining in the range of /approximately/0.75-0.85 for GTAW and somewhat less for PAW. Values of melting efficiency for Ni were slightly less than those for 304 when compared at similar travel speeds, though both tended toward the same limit (/approximately/0.4). The PAW results were not appreciably higher than the GTAW. In addition to melting efficiency the centerline depth of penetration was also measured. In contrast to the GTAW results, which increased with speed at lower travel speeds and then plateaued at 0.8 mm, the PAW results increased monotonically with speed to a maximum of 1.0 mm. In conclusion, calorimetric measurements of nonconsumable arc welding processes have been found helpful in understanding conditions under which efficient arc welds with minimal heat inputs for a desired weld penetration can be made. 10 figs.

  3. Assessing Exposures to Particulate Matter and Manganese in Welding Fumes

    E-Print Network [OSTI]

    LIU, SA

    2010-01-01T23:59:59.000Z

    less hazardous compared to MIG welding, these areas as wellareas where high concentrations occurred; 3) although resistance welding is considered less hazardoushazardous welding operations such as resistance welding should also be effectively controlled. Those who work in areas

  4. THE NEED FOR A NEW JOINING TECHNOLOGY FOR THE CLOSURE WELDING OF RADIOACTIVE MATERIALS CONTAINERS

    SciTech Connect (OSTI)

    CANNELL GR; HILL BE; GRANT GJ

    2008-10-29T23:59:59.000Z

    One of the activities associated with cleanup throughout the Department of Energy (DOE) complex is packaging radioactive materials into storage containers. Much of this work will be performed in high-radiation environments requiring fully remote operations, for which existing, proven systems do not currently exist. These conditions demand a process that is capable of producing acceptable (defect-free) welds on a consistent basis; the need to perform weld repair, under fully-remote operations, can be extremely costly and time consuming. Current closure welding technology (fusion welding) is not well suited for this application and will present risk to cleanup cost and schedule. To address this risk, Fluor and the Pacific Northwest National Laboratory (PNNL), are proposing that a new and emerging joining technology, Friction Stir Welding (FSW), be considered for this work. FSW technology has been demonstrated in other industries (aerospace and marine) to produce near flaw-free welds on a consistent basis. FSW is judged capable of providing the needed performance for fully-remote closure welding of containers for radioactive materials for the following reasons: FSW is a solid-state process; material is not melted. As such, FSW does not produce the type of defects associated with fusion welding, e.g., solidification-induced porosity, cracking, distortion due to weld shrinkage, and residual stress. In addition, because FSW is a low-heat input process, material properties (mechanical, corrosion and environmental) are preserved and not degraded as can occur with 'high-heat' fusion welding processes. When compared to fusion processes, FSW produces extremely high weld quality. FSW is performed using machine-tool technology. The equipment is simple and robust and well-suited for high radiation, fully-remote operations compared to the relatively complex equipment associated with the fusion-welding processes. Additionally, for standard wall thicknesses of radioactive materials containers, the FSW process can perform final closure welding in a single pass (GTAW requires multiple passes) resulting in increased productivity. Together, the performance characteristics associated with FSW, i.e., high weld quality, simple machine-tool equipment and increased welding efficiency, are expected to reduce risk to upcoming DOE radioactive materials packaging campaigns. FSW technology requires some development/adaptation for this application, along with approval from the governing code of construction prior to production operations. This paper addresses the need for a new joining technology, a description of the FSW process and why it is well-suited for this application, and several activities required for commercialization.

  5. Effects of welding fumes on nuclear air cleaning system carbon adsorber banks

    SciTech Connect (OSTI)

    Roberson, P.W. [Duke Power Company, Huntersville, NC (United States)

    1997-08-01T23:59:59.000Z

    Standard Technical Specifications for nuclear air cleaning systems include requirements for surveillance tests following fire, painting, or chemical release in areas communicating with the affected system. To conservatively implement this requirement, many plants categorize welding as a chemical release process, and institute controls to ensure that welding fumes do not interact with carbon adsorbers in a filter system. After reviewing research data that indicated welding had a minimal impact on adsorber iodine removal efficiency, further testing was performed with the goal of establishing a welding threshold. It was anticipated that some quantity of weld electrodes could be determined that had a corresponding detrimental impact on iodine removal efficiency for the exposed adsorber. This value could be used to determine a conservative sampling schedule that would allow the station to perform laboratory testing to ensure system degradation did not occur without a full battery of surveillance tests. A series of tests was designed to demonstrate carbon efficiency versus cumulative welding fume exposure. Three series of tests were performed, one for each of three different types of commonly used weld electrodes. Carbon sampling was performed at baseline conditions, and every five pounds of electrode thereafter. Two different laboratory tests were performed for each sample; one in accordance with ASTM 3803/1989 at 95% relative humidity and 30 degrees C, and another using the less rigorous conditions of 70% relative humidity and 80 degrees C. Review of the test data for all three types of electrodes failed to show a significant correlation between carbon efficiency degradation and welding fume exposure. Accordingly, welding is no longer categorized as a `chemical release process` at McGuire Nuclear Station, and limits on welding fume interaction with ventilation systems have been eliminated. 4 refs., 3 figs., 1 tab.

  6. Method for enhanced control of welding processes

    DOE Patents [OSTI]

    Sheaffer, Donald A. (Livermore, CA); Renzi, Ronald F. (Tracy, CA); Tung, David M. (Livermore, CA); Schroder, Kevin (Pleasanton, CA)

    2000-01-01T23:59:59.000Z

    Method and system for producing high quality welds in welding processes, in general, and gas tungsten arc (GTA) welding, in particular by controlling weld penetration. Light emitted from a weld pool is collected from the backside of a workpiece by optical means during welding and transmitted to a digital video camera for further processing, after the emitted light is first passed through a short wavelength pass filter to remove infrared radiation. By filtering out the infrared component of the light emitted from the backside weld pool image, the present invention provides for the accurate determination of the weld pool boundary. Data from the digital camera is fed to an imaging board which focuses on a 100.times.100 pixel portion of the image. The board performs a thresholding operation and provides this information to a digital signal processor to compute the backside weld pool dimensions and area. This information is used by a control system, in a dynamic feedback mode, to automatically adjust appropriate parameters of a welding system, such as the welding current, to control weld penetration and thus, create a uniform weld bead and high quality weld.

  7. Effect of friction stir weld defects on fatigue lifetime of an Al-Cu-Li alloy T. Le Jolu, T.F. Morgeneyer, A.F. Gourgues-Lorenzon

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    1 Effect of friction stir weld defects on fatigue lifetime of an Al-Cu-Li alloy (AA-2198) T. Le of friction stir welds of a 2198 Al-alloy in T851 condition has been assessed experimentally by investigating concerning crack initiation mechanisms. KEYWORDS Friction Stir Welding, Joint Line Remnant, Al-Cu-Li, S

  8. Dynamic Characterization of Spot Welds

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    modes, and fail more often under impact? - What are the roles of alloy composition and welding parameters in the change in failure mode? - What would it take to have crash model...

  9. Welding Development W87 Baseline

    SciTech Connect (OSTI)

    A. Newman; G. Gibbs; G. K. Hicken

    1998-11-01T23:59:59.000Z

    This report covers the development activities used to qualify the Gas Tungsten Arc (FTA) girth weld and the resistance stem attachments on the W87 Base Line (W87BL). Design of experiments was used throughout the development activities.

  10. Welding : arc-welded joints in aluminium and its alloys : quality levels for imperfections : technical corrigendum 1

    E-Print Network [OSTI]

    International Organization for Standardization. Geneva

    2006-01-01T23:59:59.000Z

    Welding : arc-welded joints in aluminium and its alloys : quality levels for imperfections : technical corrigendum 1

  11. Upgraded HFIR Fuel Element Welding System

    SciTech Connect (OSTI)

    Sease, John D [ORNL

    2010-02-01T23:59:59.000Z

    The welding of aluminum-clad fuel plates into aluminum alloy 6061 side plate tubing is a unique design feature of the High Flux Isotope Reactor (HFIR) fuel assemblies as 101 full-penetration circumferential gas metal arc welds (GMAW) are required in the fabrication of each assembly. In a HFIR fuel assembly, 540 aluminum-clad fuel plates are assembled into two nested annular fuel elements 610 mm (24-inches) long. The welding process for the HFIR fuel elements was developed in the early 1960 s and about 450 HFIR fuel assemblies have been successfully welded using the GMAW process qualified in the 1960 s. In recent years because of the degradation of the electronic and mechanical components in the old HFIR welding system, reportable defects in plate attachment or adapter welds have been present in almost all completed fuel assemblies. In October 2008, a contract was awarded to AMET, Inc., of Rexburg, Idaho, to replace the old welding equipment with standard commercially available welding components to the maximum extent possible while maintaining the qualified HFIR welding process. The upgraded HFIR welding system represents a major improvement in the welding system used in welding HFIR fuel elements for the previous 40 years. In this upgrade, the new inner GMAW torch is a significant advancement over the original inner GMAW torch previously used. The innovative breakthrough in the new inner welding torch design is the way the direction of the cast in the 0.762 mm (0.030-inch) diameter aluminum weld wire is changed so that the weld wire emerging from the contact tip is straight in the plane perpendicular to the welding direction without creating any significant drag resistance in the feeding of the weld wire.

  12. ABSTRACT. Keyhole plasma arc welding is a unique arc welding process for deep

    E-Print Network [OSTI]

    Zhang, YuMing

    ABSTRACT. Keyhole plasma arc welding is a unique arc welding process for deep penetration. To ensure the quality of the welds, the presence of the keyhole is crit- ical. Understanding of the keyhole will certainly benefit the improvement of the process and weld quality. Currently, the size of the keyhole

  13. Chapter 7 -Welding The dangers in welding, cutting, heating and grinding should never be underestimated.

    E-Print Network [OSTI]

    36 Chapter 7 - Welding The dangers in welding, cutting, heating and grinding should never and to understand the hazards involved. Spot the hazard Hazards associated with welding include: The arc itself eyes can become extremely red and sore and in extreme cases suffer permanent damage. Welding gases

  14. MATHEHATICAL NODELING OF THE TEHPERATURE PROFILES AND WELD DILUTION IN ELECTROSLAG WELDING OF STEEL PLATES

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) MATHEHATICAL NODELING OF THE TEHPERATURE PROFILES AND WELD DILUTION IN ELECTROSLAG WELDING describes a calculation procedure for the detailed predic- tion of temperature profiles and weld dilution in the electroslag welding of mild steel plates. The temperature profiles in the liquid slag and the liquid metal

  15. Crack growth rates of nickel alloy welds in a PWR environment.

    SciTech Connect (OSTI)

    Alexandreanu, B.; Chopra, O. K.; Shack, W. J.; Energy Technology

    2006-05-31T23:59:59.000Z

    In light water reactors (LWRs), vessel internal components made of nickel-base alloys are susceptible to environmentally assisted cracking. A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals. A program is being conducted at Argonne National Laboratory to evaluate the resistance of Ni alloys and their welds to environmentally assisted cracking in simulated LWR coolant environments. This report presents crack growth rate (CGR) results for Alloy 182 shielded-metal-arc weld metal in a simulated pressurized water reactor (PWR) environment at 320 C. Crack growth tests were conducted on 1-T compact tension specimens with different weld orientations from both double-J and deep-groove welds. The results indicate little or no environmental enhancement of fatigue CGRs of Alloy 182 weld metal in the PWR environment. The CGRs of Alloy 182 in the PWR environment are a factor of {approx}5 higher than those of Alloy 600 in air under the same loading conditions. The stress corrosion cracking for the Alloy 182 weld is close to the average behavior of Alloy 600 in the PWR environment. The weld orientation was found to have a profound effect on the magnitude of crack growth: cracking was found to propagate faster along the dendrites than across them. The existing CGR data for Ni-alloy weld metals have been compiled and evaluated to establish the effects of key material, loading, and environmental parameters on CGRs in PWR environments. The results from the present study are compared with the existing CGR data for Ni-alloy welds to determine the relative susceptibility of the specific Ni-alloy weld to environmentally enhanced cracking.

  16. Numerical simulation of linear fiction welding (LFW) processes

    SciTech Connect (OSTI)

    Fratini, L.; La Spisa, D. [University of Palermo-Dept. of Industrial engineering (Italy)

    2011-05-04T23:59:59.000Z

    Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. This paper is a comparative test between the numerical model in two dimensions, i.e. in plane strain conditions, and in three dimensions of a LFW process of AISI1045 steel specimens. It must be observed that the 3D model assures a faithful simulation of the actual threedimensional material flow, even if the two-dimensional simulation computational times are very short, a few hours instead of several ones as the 3D model. The obtained results were compared with experimental values found out in the scientific literature.

  17. Repair welding of fusion reactor components

    SciTech Connect (OSTI)

    Chin, B.A.

    1993-05-15T23:59:59.000Z

    Experiments have shown that irradiated Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 MPa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  18. Investigation on the Interface Morphologies of Explosive Welding of Inconel 625 to Steel A516 Plates

    SciTech Connect (OSTI)

    Mousavi, S. A. A. Akbari; Zareie, H. R. [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2011-01-17T23:59:59.000Z

    The purpose of this study is to produce composite plates by explosive cladding process. This is a process in which the controlled energy of explosives is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored through parallel geometry route with different operational parameters. In this investigation, a two-pronged study was adopted to establish the conditions required for producing successful solid state welding: (a) Analytical calculations to determine the weldability domain or welding window; (b) Metallurgical investigations of explosive welding experiments carried out under different explosive ratios to produce both wavy and straight interfaces. The analytical calculations confirm the experimental results. Optical microscopy studies show that a transition from a smooth to wavy interface occurs with an increase in explosive ratio. SEM studies show that the interface was outlined by characteristic sharp transition between two materials.

  19. Optimization Online - Nonlinear Optimization Submissions - 2013

    E-Print Network [OSTI]

    Second-order necessary conditions in Pontryagin form for optimal control problems ... of Linear-Quadratic Optimal Control Problems for Two-Steps Systems

  20. Pre-resistance-welding resistance check

    DOE Patents [OSTI]

    Destefan, Dennis E. (Broomfield, CO); Stompro, David A. (Idaho Falls, ID)

    1991-01-01T23:59:59.000Z

    A preweld resistance check for resistance welding machines uses an open circuited measurement to determine the welding machine resistance, a closed circuit measurement to determine the parallel resistance of a workpiece set and the machine, and a calculation to determine the resistance of the workpiece set. Any variation in workpiece set or machine resistance is an indication that the weld may be different from a control weld.

  1. Nuclear Energy Plant Optimization (NEPO) final report on aging and condition monitoring of low-voltage cable materials.

    SciTech Connect (OSTI)

    Assink, Roger Alan; Gillen, Kenneth Todd; Bernstein, Robert

    2005-11-01T23:59:59.000Z

    This report summarizes results generated on a 5-year cable-aging program that constituted part of the Nuclear Energy Plant Optimization (NEPO) program, an effort cosponsored by the U. S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI). The NEPO cable-aging effort concentrated on two important issues involving the development of better lifetime prediction methods as well as the development and testing of novel cable condition-monitoring (CM) techniques. To address improved life prediction methods, we first describe the use of time-temperature superposition principles, indicating how this approach improves the testing of the Arrhenius model by utilizing all of the experimentally generated data instead of a few selected and processed data points. Although reasonable superposition is often found, we show several cases where non-superposition is evident, a situation that violates the constant acceleration assumption normally used in accelerated aging studies. Long-term aging results over extended temperature ranges allow us to show that curvature in Arrhenius plots for elongation is a common occurrence. In all cases the curvature results in a lowering of the Arrhenius activation energy at lower temperatures implying that typical extrapolation of high temperature results over-estimates material lifetimes. The long-term results also allow us to test the significance of extrapolating through the crystalline melting point of semi-crystalline materials. By utilizing ultrasensitive oxygen consumption (UOC) measurements, we show that it is possible to probe the low temperature extrapolation region normally inaccessible to conventional accelerated aging studies. This allows the quantitative testing of the often-used Arrhenius extrapolation assumption. Such testing indicates that many materials again show evidence of ''downward'' curvature (E{sub a} values drop as the aging temperature is lowered) consistent with the limited elongation results and many literature results. It is also shown how the UOC approach allows the probing of temperatures that cross through the crystalline melting point region of semi-crystalline materials such as XLPO and EPR cable insulations. New results on combined environment aging of neoprene and hypalon cable jacketing materials are presented and offer additional evidence in support of our time-temperature-dose rate (t-T-DR) superposition approach that had been used successfully in the past for such situations.

  2. Laser Welding of Aluminum and Aluminum Alloys

    E-Print Network [OSTI]

    Eagar, Thomas W.

    .. ) Laser Welding of Aluminum and Aluminum Alloys Welds made with sharp bevel-groove weld aluminum and by aluminum alloy 5456 have been studied. The results indicate that initial absorption varies, many aluminum alloys contain magnesium or zinc, which are easily vaporized and thereby form a plasma

  3. Oxygen and Nitrogen Contamination During Arc Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) : ,- Oxygen and Nitrogen Contamination During Arc Welding T. W. Eagar Department of }faterials, shielded metal arc, self-shielded metal arc, and submerged arc welding are reviewed. Calcu- lations upon heating is also discussed. Introduction Oxygen and nitrogen ~ontamination of weld metal

  4. Selection of Processes for Welding Steel Rails

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ...._ _) Selection of Processes for Welding Steel Rails by N.S. Tsai* and T.W. Eagar* ABSTRACT 421 The advantages and limitations ofseveral conventional and prospective rail welding processes are reviewed with emphasis on the heat input rate, on joint preparation, on post weld grinding and on resultant metallurgical

  5. TRANSIENT THERMAL BEHAVIOR IN RESISTANCE SPOT WELDING

    E-Print Network [OSTI]

    Eagar, Thomas W.

    temperature response during resistance spot welding was measured and discussed with various process parameters that the measurement of temperature profiles developed during the welding process is very important in this respect composition on galvanized steel, the temperature distribution during welding was monitored in a one

  6. Energy Sources Used for Fusion Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) Energy Sources Used for Fusion Welding Thomas W. Eagar, Massachusetts Institute of Technology reliability. The Section "Fusion Welding Processes" in this Volume provides details about equipment and systems for the major fusion welding proc- esses. The purpose of this Section of the Volume is to discuss

  7. Contamination and solid state welds.

    SciTech Connect (OSTI)

    Mills, Bernice E.

    2007-05-01T23:59:59.000Z

    Since sensitivity to contamination is one of the verities of solid state joining, there is a need for assessing contamination of the part(s) to be joined, preferably nondestructively while it can be remedied. As the surfaces that are joined in pinch welds are inaccessible and thus provide a greater challenge, most of the discussion is of the search for the origin and effect of contamination on pinch welding and ways to detect and mitigate it. An example of contamination and the investigation and remediation of such a system is presented. Suggestions are made for techniques for nondestructive evaluation of contamination of surfaces for other solid state welds as well as for pinch welds. Surfaces that have good visual access are amenable to inspection by diffuse reflection infrared Fourier transform (DRIFT) spectroscopy. Although other techniques are useful for specific classes of contaminants (such as hydrocarbons), DRIFT can be used most classes of contaminants. Surfaces such as the interior of open tubes or stems that are to be pinch welded can be inspected using infrared reflection spectroscopy. It must be demonstrated whether or not this tool can detect graphite based contamination, which has been seen in stems. For tubes with one closed end, the technique that should be investigated is emission infrared spectroscopy.

  8. Melting efficiency in fusion welding

    SciTech Connect (OSTI)

    Fuerschbach, P.W.

    1991-01-01T23:59:59.000Z

    Basic to our knowledge of the science of welding is an understanding of the melting efficiency, which indicates how much of the heat deposited by the welding process is used to produce melting. Recent calorimetric studies of GTAW, PAW, and LBW processes have measured the net heat input to the part thereby quantifying the energy transfer efficiency and in turn permitting an accurate determination of the melting efficiency. It is indicated that the weld process variables can dramatically affect the melting efficiency. This limiting value is shown to depend on the weld heat flow geometry as predicted by analytical solutions to the heat flow equation and as demonstrated by the recent empirical data. A new dimensionless parameter is used to predict the melting efficiency and is shown to correlate extremely well with recent empirical data. This simple prediction methodology is notable because it requires only a knowledge of the weld schedule and the material properties in order to estimate melting efficiency. 22 refs., 16 figs.

  9. Percussive arc welding apparatus

    DOE Patents [OSTI]

    Hollar, Jr., Donald L. (Overland Park, KS)

    2002-01-01T23:59:59.000Z

    A percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.

  10. 3013 DE INNER CONTAINER CLOSURE WELD CORROSION EVALUATION

    SciTech Connect (OSTI)

    Mickalonis, J.

    2013-09-30T23:59:59.000Z

    Destructive evaluation (DE) of 3013 containers is one part of the U. S. Department of Energy Integrated Surveillance Program. During standard DE of 3013 containers, visual examinations for pitting and stress corrosion cracking (SCC) are performed on the accessible surfaces of the outer, inner, and convenience containers, which make up the 3013 container. As a result of 3013 DE additional analysis, the area near the inner container closure weld has been identified as being a region of increased corrosion susceptibility, which may provide a pathway for corrosive gases to the outer container. This area has a higher residual stress, an altered microstructure, and less corrosion resistant weld oxides as a result of the welding process as well as a lower temperature than other areas of the container, which may increase the absorption of moisture on the surface. The deposition of moisture in this stressed region could lead to pitting and stress corrosion cracking. During FY2013, the inner container closure weld area was more closely evaluated on several archived samples from DE containers. These containers included FY09 DE2, FY12 DE4, FY12 DE6 and FY12 DE7 and the Hanford High Moisture Container. The additional examinations included visual observations with a stereomicroscope, scanning electron microscopy along with energy dispersive spectroscopy for chemical analysis, and serial metallography of the sidewall and lid that are part of the inner container closure weld region. Pitting was observed in all the samples taken from the closure weld regions of the examined inner containers. This pitting was generally less 20 μm with most less than 5m. These pits were similar in depth to those observed in the vapor exposed surfaces of teardrops in the shelf life corrosion testing. Cracking was not observed on either the vapor-exposed surfaces of the teardrop coupons or the inner container closure weld region. Further testing is necessary to determine if the conditions in the welded inner container could support SCC during the 50 year life time for the 3013 container.

  11. Fracture toughness of Ti-6Al-4V after welding and postweld heat treatment

    SciTech Connect (OSTI)

    Murthy, K.K.; Sundaresan, S. [Indian Inst. of Tech., Madras (India). Dept. of Metallurgical Engineering

    1997-02-01T23:59:59.000Z

    The fracture toughness (J{sub IC}) of the fusion zone of Ti-6Al-4V alloy welds was studied in terms of microstructural changes in the as-welded condition and following postweld heat treatment. Gas tungsten arc and electron beam welds were produced in sheet material over a limited range of heat input and subsequently heat treated at 700 C and 900 C. In the as-welded condition, the weld microstructure was a mixture of diffusional and martensitic alpha phases, whose proportion varied wit heat input and cooling rate. The fusion zone exhibited low ductility resulting from the highly acicular microstructure and a large prior-beta grain size. Postweld heat treatment tempered the martensite and coarsened the microstructure, but a beneficial effect on ductility was realized only after treatment at 900 C. Fracture toughness in the as-welded condition was greater than for the base metal and was attributed to the lamellar microstructure of the fusion zone and absence of continuous alpha film along the grain boundaries. Postweld heat treatment at 700 C reduced the fracture toughness considerably and, as in the case of ductility, it was necessary to heat treat at 900 C to produce an improvement.

  12. Nondestructive, in-process inspection of inertia friction welding : an investigation into a new sensing technique.

    SciTech Connect (OSTI)

    Hartman, D. A. (Daniel A.); Cola, M. J. (Mark J.); Dave, V. R. (Vivek R.); Dozhier, N. G. (Nathan G.); Carpenter, R. W. (Robert W.)

    2002-01-01T23:59:59.000Z

    This paper investigates the capabilities of a new sensor for in-process monitoring of quality during friction welding. The non-contact sensor is composed of microphones that are mounted in an aluminum ring which surrounds the weld joint. The sensor collects the acoustical energy (in the form of sound pressure) that is emitted during the plastic deformation and phase transformations (if applicable) in friction welding processes. The focus in this preliminary investigation is to search for and identify features within the acoustical emission that are indicative of bond quality. Bar-to-bar inertia friction welding (one form of friction welding) of copper to 304L stainless steel is used in this proof-of-concept study. This material combination exhibits only marginal weldability and is ideally suited for validating the capabilities of this new sensing technique. A probabilistic neural network is employed in this work to analyze the acoustical emission's frequency spectrum in an attempt to classify acceptable, conditional, and unacceptable welds. Our preliminary findings indicate that quality-based process features do exist within the frequency spectrum of the acoustical signature. The results from this analysis are presented. Future work in improving the sensing and interpretation of the data is discussed in an effort to develop a robust method of quality-based, in-process monitoring of friction welds.

  13. Laser Assisted Plasma Arc Welding

    SciTech Connect (OSTI)

    FUERSCHBACH,PHILLIP W.

    1999-10-05T23:59:59.000Z

    Experiments have been performed using a coaxial end-effecter to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project goal is to develop an improved fusion welding process that exhibits both absorption robustness and deep penetration for small scale (< 1.5 mm thickness) applications. On aluminum alloys 6061 and 6111, the hybrid process has been shown to eliminate hot cracking in the fusion zone. Fusion zone dimensions for both stainless steel and aluminum were found to be wider than characteristic laser welds, and deeper than characteristic plasma arc welds.

  14. Intraluminal tissue welding for anastomosis

    DOE Patents [OSTI]

    Glinsky, Michael (Livermore, CA); London, Richard (Orinda, CA); Zimmerman, George (Lafayette, CA); Jacques, Steven (Portland, OR)

    1998-10-27T23:59:59.000Z

    A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or "welded" using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage.

  15. Intraluminal tissue welding for anastomosis

    DOE Patents [OSTI]

    Glinsky, M.; London, R.; Zimmerman, G.; Jacques, S.

    1998-10-27T23:59:59.000Z

    A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or ``welded`` using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage. 8 figs.

  16. Optimization Online Digest -- February 2015

    E-Print Network [OSTI]

    Computational Optimization of Gas Compressor Stations: MINLP Models vs. ... The Cyclic Block Conditional Gradient Method for Convex Optimization Problems

  17. Optical penetration sensor for pulsed laser welding

    DOE Patents [OSTI]

    Essien, Marcelino (Albuquerque, NM); Keicher, David M. (Albuquerque, NM); Schlienger, M. Eric (Albuquerque, NM); Jellison, James L. (Albuquerque, NM)

    2000-01-01T23:59:59.000Z

    An apparatus and method for determining the penetration of the weld pool created from pulsed laser welding and more particularly to an apparatus and method of utilizing an optical technique to monitor the weld vaporization plume velocity to determine the depth of penetration. A light source directs a beam through a vaporization plume above a weld pool, wherein the plume changes the intensity of the beam, allowing determination of the velocity of the plume. From the velocity of the plume, the depth of the weld is determined.

  18. Shimmed electron beam welding process

    DOE Patents [OSTI]

    Feng, Ganjiang (Clifton Park, NY); Nowak, Daniel Anthony (Alplaus, NY); Murphy, John Thomas (Niskayuna, NY)

    2002-01-01T23:59:59.000Z

    A modified electron beam welding process effects welding of joints between superalloy materials by inserting a weldable shim in the joint and heating the superalloy materials with an electron beam. The process insures a full penetration of joints with a consistent percentage of filler material and thereby improves fatigue life of the joint by three to four times as compared with the prior art. The process also allows variable shim thickness and joint fit-up gaps to provide increased flexibility for manufacturing when joining complex airfoil structures and the like.

  19. Crutcher introduces new automatic welding system

    SciTech Connect (OSTI)

    Not Available

    1982-04-01T23:59:59.000Z

    Designed for pipe over 16 in. but suitable for smaller diameters if modified slightly, a new automatic welding system uses the metal inert gas process to weld the root bead from the outside with a specially designed backup ring that adapts to a standard internal pipe clamp, making internal welding unnecessary. Individual welding machines travel on flexible tracks that are positioned by a track-locating device; two machines are required at each welding station. Particularly applicable to lay-barge operations, the system consists of (1) a pipe-facing machine, (2) a diesel-driven hydraulic power unit, (3) a carriage track, (4) an air-driven, air-operated, simplified pipe clamp, and (5) a welding bug assembly consisting of a carriage with drive unit, welding head, oscillator, and wire spool mount with drag-brake assembly.

  20. Performance Optimization of a Fan System- Overcoming Impacts of Modified Design Criteria Due to Regulatory Requirements and Changed Operating Conditions

    E-Print Network [OSTI]

    Wroblewski, R. G.; Preis, F.; Smith, R.

    that was applied to address fan inefficiency. Energy savings from optimizing the system are estimated to be 338 kW, nearly half of the original measured input power of 678 kW. The project is currently being implemented and will have a payback period of less than 8...

  1. Welding Induced Alignment Distortion in Dual-in-Line LD Packages

    SciTech Connect (OSTI)

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Shi, Frank G.

    2007-11-11T23:59:59.000Z

    The tolerance for the movement of a single mode fiber relative to the laser is extremely tight, a submicron movement can often lead to a significant misalignment and thus the reduction in the power coupled into the fiber. Among various fiber pigtailing assembly technologies, pulsed laser welding is the method with submicron accuracy and is most conducive to automation. However, the melting-solidification process during laser welding can often distort the pre-achieved fiber-optic alignment. This Welding-Induced-Alignment-Distortion (WIAD) is a serious concern and significantly affects the yield for single mode fiber pigtailing to a semiconductor laser. In this paper, effect of laser welding sequence on WIAD in a dual-in-line packager is numerically investigated by means of Finite Element Method (FEM). Optimal welding sequence may minimize WIAD in dual-in-line package. Additionally, unsymmetrical space between fiber and U-channel induced by laser welding of U-channelto-plate in DIP LD packages is found to have obvious effect on WIAD.

  2. Application of Taguchi method in Nd-YAG laser welding of super duplex stainless steel

    SciTech Connect (OSTI)

    Yip, W.M.; Man, H.C.; Ip, W.H. [Hong Kong Polytechnic Univ., Kowloon (Hong Kong)

    1996-12-31T23:59:59.000Z

    This investigation is aimed at achieving a near 50-50 % ferrite-austenite ratio of laser welded super duplex stainless steel, UNS S 32760 (Zeron 100). Bead-on-plate welding has been carried out using a 2 kW Nd-YAG laser with 3 different kinds of wave form, Continuous, Sine and Square wave. The weld metals were examined with respect to the phase volume contents by X-ray diffraction. Laser welding involved a large number of variables, interaction and levels of variables. Taguchi Method was selected and used to reduce the number of experimental conditions and to identify the dominant factors. The optimum combinations of controllable factors were found from each set of wave form. The optimum 40-60% ferrite-austenite ratio were realized on some of the combination parameter groups after using the Parameter Design method.

  3. Survey of welding processes for field fabrication of 2 1/4 Cr-1 Mo steel pressure vessels. [128 references

    SciTech Connect (OSTI)

    Grotke, G.E.

    1980-04-01T23:59:59.000Z

    Any evaluation of fabrication methods for massive pressure vessels must consider several welding processes with potential for heavy-section applications. These include submerged-arc and shielded metal-arc, narrow-joint modifications of inert-gas metal-arc and inert-gas tungsten-arc processes, electroslag, and electron beam. The advantage and disadvantages of each are discussed. Electroslag welding can be dropped from consideration for joining of 2 1/4 Cr-1 Mo steel because welds made with this method do not provide the required mechanical properties in the welded and stress relieved condition. The extension of electron-beam welding to sections as thick as 4 or 8 inches (100 or 200 mm) is too recent a development to permit full evaluation. The manual shielded metal-arc and submerged-arc welding processes have both been employed, often together, for field fabrication of large vessels. They have the historical advantage of successful application but present other disadvantages that make them otherwise less attractive. The manual shielded metal-arc process can be used for all-position welding. It is however, a slow and expensive technique for joining heavy sections, requires large amounts of skilled labor that is in critically short supply, and introduces a high incidence of weld repairs. Automatic submerged-arc welding has been employed in many critical applications and for welding in the flat position is free of most of the criticism that can be leveled at the shielded metal-arc process. Specialized techniques have been developed for horizontal and vertical position welding but, used in this manner, the applications are limited and the cost advantage of the process is lost.

  4. Random Curves by Conformal Welding

    E-Print Network [OSTI]

    K. Astala; P. Jones; A. Kupiainen; E. Saksman

    2009-12-17T23:59:59.000Z

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle given in terms of the exponential of Gaussian Free Field. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  5. Random Curves by Conformal Welding

    E-Print Network [OSTI]

    Astala, K; Kupiainen, A; Saksman, E

    2009-01-01T23:59:59.000Z

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle given in terms of the exponential of Gaussian Free Field. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  6. Effect of Welding Speed and Defocusing Distance on the Quality of Laser Welded Ti-6Al-4V

    E-Print Network [OSTI]

    Medraj, Mamoun

    Effect of Welding Speed and Defocusing Distance on the Quality of Laser Welded Ti-6Al-4V A:YAG laser, Laser welding, Ti-6Al-4V alloy Abstract In this study, the weldability of 5.1-mm thick Ti-6Al-4V at various welding speeds and defocusing distances. The joint quality was characterized in terms of weld

  7. Heat transfer in gas tungsten arc welding

    SciTech Connect (OSTI)

    Smartt, H.B.; Stewart, J.A.; Einerson, C.J.

    1986-05-01T23:59:59.000Z

    The heat transferred from an electrode negative, argon gas tungsten arc to an anode has been measured for a wide range of conditions suitable for mechanized welding applications. The results are given as (1) the arc efficiency; and (2) the anode heat and current input distribution functional shapes and radii for various anode materials and groove shapes over a wide range of current and voltage, using different electrode geometries, as well as both He and Ar-He shielding gases. The nominal arc is Gaussian with a diameter of about 4 mm and a heat transfer efficiency to the anode of about 75%. Variations from these values are discussed in terms of current knowledge of the electrical and thermal energy transport mechanisms. A new method of measuring the heat transferred from the arc to the anode, using a boiling liquid nitrogen calorimeter, has been developed which gives rapid, accurate values.

  8. Innovative Method for Performance Inspections often save 20-30% through Optimization of Air-Conditioning and Refrigeration

    E-Print Network [OSTI]

    Berglof, K.

    2010-01-01T23:59:59.000Z

    Air-conditioning, refrigeration and heat pump equipment is using 15 to 20% of the electrical energy globally. Many times these systems do not operate in an effective way. The paper present a method for and experience from performance testing...

  9. NEW NUMERICAL TECHNOLOGIES FOR THE SIMULATION OF ARC WELDING PROCESSES

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    NEW NUMERICAL TECHNOLOGIES FOR THE SIMULATION OF ARC WELDING PROCESSES Michel Bellet 1 , Makhlouf Antipolis, France; soudage@transvalor.com Keywords: welding, finite elements, material deposit, adaptive for arc welding simulation and analysis. The new numerical technologies essentially consist first

  10. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, H.B.

    1992-10-13T23:59:59.000Z

    A method is described for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical canister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel's recessed bottom. Also, the channel design limits distortion of the two members during the friction welding process, further contributing to the complete seal that is obtained. 5 figs.

  11. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, Harold B. (867 N. Belair Rd., Evans, GA 30809)

    1992-01-01T23:59:59.000Z

    A method for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical cannister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel's recessed bottom. Also, the channel design limits distortion of the two members during the friction welding process, further contributing to the complete seal that is obtained.

  12. Passively damped vibration welding system and method

    DOE Patents [OSTI]

    Tan, Chin-An; Kang, Bongsu; Cai, Wayne W.; Wu, Tao

    2013-04-02T23:59:59.000Z

    A vibration welding system includes a controller, welding horn, an anvil, and a passive damping mechanism (PDM). The controller generates an input signal having a calibrated frequency. The horn vibrates in a desirable first direction at the calibrated frequency in response to the input signal to form a weld in a work piece. The PDM is positioned with respect to the system, and substantially damps or attenuates vibration in an undesirable second direction. A method includes connecting the PDM having calibrated properties and a natural frequency to an anvil of an ultrasonic welding system. Then, an input signal is generated using a weld controller. The method includes vibrating a welding horn in a desirable direction in response to the input signal, and passively damping vibration in an undesirable direction using the PDM.

  13. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, H.B.

    1991-01-01T23:59:59.000Z

    A method for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical cannister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel`s recessed bottom. Also, the channel design limits distortion of the two members during the friction welding, process, further contributing to the complete seal that is obtained.

  14. Promising Inspection Technique for Vehicle Welding Offers Efficient...

    Office of Environmental Management (EM)

    Promising Inspection Technique for Vehicle Welding Offers Efficient Alternative Promising Inspection Technique for Vehicle Welding Offers Efficient Alternative April 22, 2015 -...

  15. THE DEVELOPMENT OF MICROSTRUCTURE IN DUPLEX STAINLESS STEEL WELDS

    E-Print Network [OSTI]

    Cambridge, University of

    THE DEVELOPMENT OF MICROSTRUCTURE IN DUPLEX STAINLESS STEEL WELDS by Naseem Issa Abdallah Haddad;The Development of Microstructure in Duplex Stainless Steel Welds Abstract Duplex stainless steels

  16. Welding the AT-400A Containment Vessel

    SciTech Connect (OSTI)

    Brandon, E.

    1998-11-01T23:59:59.000Z

    Early in 1994, the Department of Energy assigned Sandia National Laboratories the responsibility for designing and providing the welding system for the girth weld for the AT-400A containment vessel. (The AT-400A container is employed for the shipment and long-term storage of the nuclear weapon pits being returned from the nation's nuclear arsenal.) Mason Hanger Corporation's Pantex Plant was chosen to be the production facility. The project was successfully completed by providing and implementing a turnkey welding system and qualified welding procedure at the Pantex Plant. The welding system was transferred to Pantex and a pilot lot of 20 AT-400A containers with W48 pits was welded in August 1997. This document is intended to bring together the AT-400A welding system and product (girth weld) requirements and the activities conducted to meet those requirements. This document alone is not a complete compilation of the welding development activities but is meant to be a summary to be used with the applicable references.

  17. Lienert named American Welding Society Fellow

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and industry with great distinction as an individual who contributed significantly to the knowledge, science, and application of welding," the society said in a statement. Research...

  18. Welding shield for coupling heaters

    DOE Patents [OSTI]

    Menotti, James Louis (Dickinson, TX)

    2010-03-09T23:59:59.000Z

    Systems for coupling end portions of two elongated heater portions and methods of using such systems to treat a subsurface formation are described herein. A system may include a holding system configured to hold end portions of the two elongated heater portions so that the end portions are abutted together or located near each other; a shield for enclosing the end portions, and one or more inert gas inlets configured to provide at least one inert gas to flush the system with inert gas during welding of the end portions. The shield may be configured to inhibit oxidation during welding that joins the end portions together. The shield may include a hinged door that, when closed, is configured to at least partially isolate the interior of the shield from the atmosphere. The hinged door, when open, is configured to allow access to the interior of the shield.

  19. Improvement of reliability of welding by in-process sensing and control (development of smart welding machines for girth welding of pipes). Final report

    SciTech Connect (OSTI)

    Hardt, D.E.; Masubuchi, K.; Paynter, H.M.; Unkel, W.C.

    1983-04-01T23:59:59.000Z

    Closed-loop control of the welding variables represents a promising, cost-effective approach to improving weld quality and therefore reducing the total cost of producing welded structures. The ultimate goal is to place all significant weld variables under direct closed-loop control; this contrasts with preprogrammed machines which place the welding equipment under control. As the first step, an overall strategy has been formulated and an investigation of weld pool geometry control for gas tungsten arc process has been completed. The research activities were divided into the areas of arc phenomena, weld pool phenomena, sensing techniques and control activities.

  20. Pessimistic Bilevel Optimization

    E-Print Network [OSTI]

    Wiesemann, Wolfram

    We study a variant of the pessimistic bilevel optimization problem, which comprises constraints that must be satisfied for any optimal solution of a subordinate (lower-level) optimization problem. We present conditions ...

  1. The Effect of Weld Residual Stress on Life of Used Nuclear Fuel Dry Storage Canisters

    SciTech Connect (OSTI)

    Ronald G. Ballinger; Sara E. Ferry; Bradley P. Black; Sebastien P. Teysseyre

    2013-08-01T23:59:59.000Z

    With the elimination of Yucca Mountain as the long-term storage facility for spent nuclear fuel in the United States, a number of other storage options are being explored. Currently, used fuel is stored in dry-storage cask systems constructed of steel and concrete. It is likely that used fuel will continue to be stored at existing open-air storage sites for up to 100 years. This raises the possibility that the storage casks will be exposed to a salt-containing environment for the duration of their time in interim storage. Austenitic stainless steels, which are used to construct the canisters, are susceptible to stress corrosion cracking (SCC) in chloride-containing environments if a continuous aqueous film can be maintained on the surface and the material is under stress. Because steel sensitization in the canister welds is typically avoided by avoiding post-weld heat treatments, high residual stresses are present in the welds. While the environment history will play a key role in establishing the chemical conditions for cracking, weld residual stresses will have a strong influence on both crack initiation and propagation. It is often assumed for modeling purposes that weld residual stresses are tensile, high and constant through the weld. However, due to the strong dependence of crack growth rate on stress, this assumption may be overly conservative. In particular, the residual stresses become negative (compressive) at certain points in the weld. The ultimate goal of this research project is to develop a probabilistic model with quantified uncertainties for SCC failure in the dry storage casks. In this paper, the results of a study of the residual stresses, and their postulated effects on SCC behavior, in actual canister welds are presented. Progress on the development of the model is reported.

  2. Modelling of friction stir welding

    E-Print Network [OSTI]

    Colegrove, Paul Andrew

    is influenced by the fractUling of the tungsten wire. Finally, Nowak et al. 85 examined the flow during the FSW of polycarbonate and found similar flow fields to those observed in aluminium. Because of polycarbonate's different properties it was necessary... is conducted into the tool and welded material, and is then convected from the top surface or conducted into the backing plate. Both analytical and numerical models have been used to describe this heat flow. The following section describes thermal modelling...

  3. In: O'Brien R L (ed.) Welding Handbook-Volume 3: Materials and Applications, 8th Edn. American Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    (fastening, adhesive bonding, soldering, brazing, arc welding, diffusion bonding, resistance welding, etc, such as diffusion bonding, come very close to this ideal; .. .' .. . . . : ' : \\. :-';... .: ... Joining

  4. Polymer Welding: Strength Through Entanglements

    E-Print Network [OSTI]

    Ting Ge; Flint Pierce; Dvora Perahia; Gary S. Grest; Mark O. Robbins

    2012-11-29T23:59:59.000Z

    Large-scale simulations of thermal welding of polymers are performed to investigate the rise of mechanical strength at the polymer-polymer interface with the welding time. The welding process is in the core of integrating polymeric elements into devices as well as in thermal induced healing of polymers; processes that require development of interfacial strength equal to that of the bulk. Our simulations show that the interfacial strength saturates at the bulk shear strength much before polymers diffuse by their radius of gyration. Along with the strength increase, the dominant failure mode changes from chain pullout at the interface to chain scission as in the bulk. Formation of sufficient entanglements across the interface, which we track using a Primitive Path Analysis is required to arrest catastrophic chain pullout at the interface. The bulk response is not fully recovered until the density of entanglements at the interface reaches the bulk value. Moreover, the increase of interfacial strength before saturation is proportional to the number of interfacial entanglements between chains from opposite sides.

  5. Integrity assessment of the ferritic / austenitic dissimilar weld joint between intermediate heat exchanger and steam generator in fast reactor

    SciTech Connect (OSTI)

    Jayakumar, T.; Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Goyal, S.; Kumar, J. G.; Mathew, M. D. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam- 603 102 (India)

    2012-07-01T23:59:59.000Z

    Integrity of the modified 9Cr-1Mo / alloy 800 dissimilar joint welded with Inconel 182 electrodes has been assessed under creep condition based on the detailed analysis of microstructure and stress distribution across the joint by finite element analysis. A hardness peak at the ferritic / austenitic weld interface and a hardness trough at the inter-critical heat affected zone (HAZ) in ferritic base metal developed. Un-tempered martensite was found at the ferritic / austenitic weld interface to impart high hardness in it; whereas annealing of martensitic structure of modified 9Cr-1Mo steel by inter-critical heating during welding thermal cycle resulted in hardness tough in the inter-critical HAZ. Creep tests were carried out on the joint and ferritic steel base metal at 823 K over a stress range of 160-320 MPa. The joint possessed lower creep rupture strength than its ferritic steel base metal. Failure of the joint at relatively lower stresses occurred at the ferritic / austenitic weld interface; whereas it occurred at inter-critical region of HAZ at moderate stresses. Cavity nucleation associated with the weld interface particles led to premature failure of the joint. Finite element analysis of stress distribution across the weld joint considering the micro-mechanical strength inhomogeneity across it revealed higher von-Mises and principal stresses at the weld interface. These stresses induced preferential creep cavitation at the weld interface. Role of precipitate in enhancing creep cavitation at the weld interface has been elucidated based on the FE analysis of stress distribution across it. (authors)

  6. Estimate of the allowable dimensions of diagnosed defects in category III and IV welded pipeline joints{sup 1}

    SciTech Connect (OSTI)

    Grin', E. A.; Bochkarev, V. I. [JSC 'All-Russia Thermal Engineering Institute' (JSC 'VTI') (Russian Federation)] [JSC 'All-Russia Thermal Engineering Institute' (JSC 'VTI') (Russian Federation)

    2013-01-15T23:59:59.000Z

    An approach for estimating the permissible dimensions of technological defects in butt welded joints in category III and IV pipelines is described. The allowable size of a welding defect is determined from the condition of compliance with the specifications on strength for a reference cross section (damaged joint) of the pipeline taking into account its weakening by a given defect.With regard to the fairly widespread discovery of technological defects in butt welded joints during diagnostics of auxiliary pipelines for thermal electric power plants, the proposed approach can be used in practice by repair and consulting organizations.

  7. Parametric Studies Of Weld Quality Of Tungsten Inert Gas Arc Welding Of Stainless Steel

    SciTech Connect (OSTI)

    Kumar Pal, Pradip; Nandi, Goutam; Ghosh, Nabendu [Mechanical Engineering Department, Jadavpur University, Kolkata-700032 (India)

    2011-01-17T23:59:59.000Z

    Effect of current and gas flow rate on quality of weld in tungsten inter gas arc welding of austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current and gas flow rate. The quality of the weld has been evaluated in terms of ultimate and breaking strengths of the welded specimens. The observed data have been interpreted, discussed and analyzed by using Grey--Taguchi methodology. Optimum parametric setting has been predicted and validated as well.

  8. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect (OSTI)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-12-01T23:59:59.000Z

    The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

  9. SmartWeld working session for the GTS4

    SciTech Connect (OSTI)

    Kleban, S. [Sandia National Labs., Albuquerque, NM (United States); Hicken, K.; Ng, R. [Sandia National Labs., Livermore, CA (United States); Fricke, B. [Allied Signal Kansas City Division, MO (United States)

    1997-08-01T23:59:59.000Z

    Results from SmartWeld`s first working session involving in-progress designs is presented. The Welding Advisor component of SmartWeld was thoroughly exercised, evaluated all eleven welds of the selected part. The Welding Advisor is an expert system implemented with object-oriented techniques for knowledge representation. With two welding engineers in attendance, the recommendations of the Welding Advisor were thoroughly examined and critiqued for accuracy and for areas of improvement throughout the working session. The Weld Schedule Database component of SmartWeld was also exercised. It is a historical archive of proven, successful weld schedules that can be intelligently searched using the current context of SmartWeld`s problem solving state. On all eleven welds, the experts agreed that Welding Advisor recommended the most risk free options. As a result of the Advisor`s recommendation, six welds agreed completely with the experts, two welds had their joint geometry modified for production, and three welds were not modified but extra care was exercised during welding. 25 figs., 3 tabs.

  10. Seal welded cast iron nuclear waste container

    DOE Patents [OSTI]

    Filippi, Arthur M. (Pittsburgh, PA); Sprecace, Richard P. (Murrysville, PA)

    1987-01-01T23:59:59.000Z

    This invention identifies methods and articles designed to circumvent metallurgical problems associated with hermetically closing an all cast iron nuclear waste package by welding. It involves welding nickel-carbon alloy inserts which are bonded to the mating plug and main body components of the package. The welding inserts might be bonded in place during casting of the package components. When the waste package closure weld is made, the most severe thermal effects of the process are restricted to the nickel-carbon insert material which is far better able to accommodate them than is cast iron. Use of nickel-carbon weld inserts should eliminate any need for pre-weld and post-weld heat treatments which are a problem to apply to nuclear waste packages. Although the waste package closure weld approach described results in a dissimilar metal combination, the relative surface area of nickel-to-iron, their electrochemical relationship, and the presence of graphite in both materials will act to prevent any galvanic corrosion problem.

  11. Thermochemical Analysis of Hydrogen Absorption in Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    '' .' j I ~l Thermochemical Analysis of Hydrogen Absorption in Welding A new model that addresses the shortcomings of Sievert's law for predicting hydrogen absorption is proposed ABSTRACT. A systematic review of diatomic hydrogen) to calcu· late the hydrogen absorption reaction temperature in the weld pool is invalid

  12. Manual tube-to-tubesheet welding torch

    DOE Patents [OSTI]

    Kiefer, Joseph H. (Tampa, FL); Smith, Danny J. (Tampa, FL)

    1982-01-01T23:59:59.000Z

    A welding torch made of a high temperature plastic which fits over a tube intermediate the ends thereof for welding the juncture between the tube and the back side of a tube plate and has a ballooned end in which an electrode, filler wire guide, fiber optic bundle, and blanketing gas duct are disposed.

  13. Design of Welding Alloys Creep and Toughness

    E-Print Network [OSTI]

    Marimuthu, Murugananth

    The subject of welding is challenging because of its complexity and because its applications are in the majority of cases, safety critical. The work presented in this thesis deals with both these aspects from the point of view of welding alloys...

  14. CLOSURE WELD DEVELOPMENT FOR 3013 OUTER CONTAINERS

    SciTech Connect (OSTI)

    Daugherty, W.; Howard, S.; Peterson, K.; Stokes, M.

    2009-11-10T23:59:59.000Z

    Excess plutonium materials in the DOE complex are packaged and stored in accordance with DOE-STD-3013. This standard specifies requirements for the stabilization of such materials and subsequent packaging in dual nested seal-welded containers. Austenitic stainless steels have been selected for container fabrication. The inner 3013 container provides contamination control while the outer 3013 container is the primary containment vessel and is the focus of this paper. Each packaging site chose a process for seal welding the outer 3013 containers in accordance with its needs and expertise. The two processes chosen for weld closure were laser beam welding (LBW) and gas tungsten arc welding (GTAW). Following development efforts, each system was qualified in accordance with DOE-STD-3013 prior to production use. The 3013 outer container closure weld joint was designed to accommodate the characteristics of a laser weld. This aspect of the joint design necessitated some innovative process and equipment considerations in the application of the GTAW process. Details of the weld requirements and the development processes are presented and several potential enhancements for the GTAW system are described.

  15. Development of models for welding applications

    SciTech Connect (OSTI)

    Roper, J.R.; Hayer, L.K.

    1990-01-01T23:59:59.000Z

    The modeling of welding processes offers considerable potential for help with manufacturing problems but a complete definition of any welding process offers many challenges. However, the modular structure of MARC, and the diverse range of capabilities offered, create a good opportunity for development in this area. This paper discusses these problems and describes techniques used to overcome some of them. Models have been developed to simulate gas tungsten arc (GTA) and electron beam (EB) welding with a moving heat source. Fortran routines for subroutines FLUX and FORCDT have been written to generate a moving heat source. Sequential element activation has permitted the simulation of GTA welding with cold wire feed (CWF), as in filling of a machined weld groove. A program which generates History Definition blocks necessary for this type of welding model is also described in this paper. Semi-infinite heat transfer elements were used to get accurate temperature histories while keeping the size of the model manageable. Time-temperature histories and isothermal contours compare well with experimental measurements, although many areas for improvement and refinement remain. Results have been used to anticipate the necessity for weld parameter changes after part redesign, and the electron beam model relates closely to situations in which information is needed for the minimization of peak temperatures on the underside of the welded part. 8 refs., 11 figs.

  16. Optimal design and control strategies for novel combined heat and power (CHP) fuel cell systems. Part I of II, datum design conditions and approach.

    SciTech Connect (OSTI)

    Colella, Whitney G.

    2010-06-01T23:59:59.000Z

    Energy network optimization (ENO) models identify new strategies for designing, installing, and controlling stationary combined heat and power (CHP) fuel cell systems (FCSs) with the goals of (1) minimizing electricity and heating costs for building owners and (2) reducing emissions of the primary greenhouse gas (GHG) - carbon dioxide (CO{sub 2}). A goal of this work is to employ relatively inexpensive simulation studies to discover more financially and environmentally effective approaches for installing CHP FCSs. ENO models quantify the impact of different choices made by power generation operators, FCS manufacturers, building owners, and governments with respect to two primary goals - energy cost savings for building owners and CO{sub 2} emission reductions. These types of models are crucial for identifying cost and CO{sub 2} optima for particular installations. Optimal strategies change with varying economic and environmental conditions, FCS performance, the characteristics of building demand for electricity and heat, and many other factors. ENO models evaluate both 'business-as-usual' and novel FCS operating strategies. For the scenarios examined here, relative to a base case of no FCSs installed, model results indicate that novel strategies could reduce building energy costs by 25% and CO{sub 2} emissions by 80%. Part I of II articles discusses model assumptions and methodology. Part II of II articles illustrates model results for a university campus town and generalizes these results for diverse communities.

  17. WELDING RESEARCH FEBRUARY 2008, VOL. 87-s44

    E-Print Network [OSTI]

    Zhang, YuMing

    WELDING RESEARCH FEBRUARY 2008, VOL. 87-s44 ABSTRACT. Consumable double- electrode gas metal arc welding (DE- GMAW) is an innovative welding process that can significantly increase the deposi- tion rate arc welding(GMAW)gunandconstantcurrent (CC) power supply to a conventional GMAW setup -- Fig. 1

  18. Subaqueous Explosive Eruption and Welding of Pyroclastic Deposits

    E-Print Network [OSTI]

    Busby, Cathy

    Subaqueous Explosive Eruption and Welding of Pyroclastic Deposits Peter Kokelaar and Cathy Busby fabrics indicative of welding of glass shards and pumice at temperatures >500"C. The occurrence emplacement temperature in pyroclas- tic deposits is welding. Welding is hot-state viscous deformation

  19. Optical Inspection of Welding Seams Fabian Timm1,2

    E-Print Network [OSTI]

    Optical Inspection of Welding Seams Fabian Timm1,2 , Thomas Martinetz1 , and Erhardt Barth1,2 1 present a framework for automatic inspection of welding seams based on specular reflections. To this end by using welding techniques. Soldering and welding techniques are common in diverse areas such as printed

  20. EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING

    E-Print Network [OSTI]

    Eagar, Thomas W.

    EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING M.L. Lin, T.W. Eagar Materials of the weld pool which are changed by these fact ors . It is shown that, at current s in excess of 300 amperes in a different heat distribution on the weld pool surface . ALTHOUGH THE GAS tungsten arc (GTA) welding process

  1. Weld Surfacing Edited by Dr I.A. Bucklow

    E-Print Network [OSTI]

    Cambridge, University of

    becomesconfigurationally frozen at a temperature of about 1150Cduring deposition by the manual-metal-arc welding techniqueV01.II Weld Surfacing Edited by Dr I.A. Bucklow ConferenceTechnicalDirector Organised by The Welding Institute in associationwith The Surface Engineering Society THE WELDING INSTITUTE #12;L

  2. What makes an electric welding arc perform its required function

    SciTech Connect (OSTI)

    Correy, T.B.

    1982-09-01T23:59:59.000Z

    The physics of direct current and alternating current welding arcs, the heat transfer of direct current welding arcs, the characteristics of dc welding and ac welding power supplies and recommendations for the procurement and maintenance of precision power supplies are discussed. (LCL)

  3. DESIGN OF THE HANFORD MULTI CANISTER OVERPACK (MCO) & DEVELOPMENT & QUALIFICATION OF THE CLOSURE WELDING PROCESS

    SciTech Connect (OSTI)

    CANNELL, G. R.

    2004-04-30T23:59:59.000Z

    Processing more than 2,100 metric tons of metallic uranium spent nuclear fuel (SNF) into large stainless steel containers called Multi-Canister Overpacks (MCOs) is one of the top priorities for the Department of Energy (DOE) at the Hanford Site, located in southeastern Washington state. The MCOs will be temporarily stored on site and eventually shipped to the federal geologic repository for long-term storage. MCOs are constructed and ''N''stamped in accordance with the requirements of the American Society of Mechanical Engineers (ASME) Section III, Division 1, Class 1 Components. Final closure welding poses a challenge after the fuel is loaded. Performing required examination and testing activities (volumetric examination and hydrostatic leak testing) can be difficult, if not impractical. An ASME Code Case N-595-3, was written specifically to allow code stamping by addressing such closures and providing alternative rules. MCOs are the first SNF canisters within the DOE complex to successfully use this code case for receiving ASME stamps. This paper discusses the design of the MCO, application of the N-595-3 code case, and development and qualification of the final welded closure. The MCO design considers internal pressure and handling loads, as well as processing and interim storage activities. The MCO functions as the primary or innermost containment as part of an overall transportation package so the design also considered interface features with secondary and transport containers. The MCO, approximately 2 feet in diameter and nearly 14 feet tall, is constructed primarily of Type 304/304L stainless steel and the final pressure boundary is of all-welded construction. The closure-weld is made with the Gas Tungsten Arc Welding (GTAW) process, using an automatic, machine-welding mode. Examination and testing of the closure includes the N-595-3 specified requirements-progressive Liquid Penetrant testing (PT) and final helium leak testing. At completion of the closure, the MCO is ''N'' stamped as a 450 pounds per square inch (design pressure) vessel. To ensure the process consistently achieves the required weld penetration, a series of developmental tests was performed to identify an optimum and robust set of welding parameters. Testing included test welds made on plate mockups and then actual MCO mockups. With the primary welding parameters (welding current and travel speed) established, a simple two-factor, two-level, factorial experiment with replication at high and low heat input conditions was conducted. Evaluation of the results included weld photomicrographs, which helped establish process range limits for these parameters broad enough to cover typical equipment and measurement variations and provide additional operating margin. To date, over 316 MCOs have been loaded, dried, and transported to the Canister Storage Building (CSB), where the welding is done. Of those, 161 MCOs have received final welded closure and ''N'' stamps. All cover cap final closure welds have met specified requirements without incident.

  4. Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology

    SciTech Connect (OSTI)

    Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

    2005-06-30T23:59:59.000Z

    Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

  5. Gas Metal Arc Welding Process Modeling and Prediction of Weld Microstructure in MIL A46100 Armor-Grade

    E-Print Network [OSTI]

    Grujicic, Mica

    Gas Metal Arc Welding Process Modeling and Prediction of Weld Microstructure in MIL A46100 Armor metal arc welding (GMAW) butt-joining process has been modeled using a two-way fully coupled, transient in the form of heat, and the mechanical material model of the workpiece and the weld is made temperature

  6. Numerical modelling of hybrid arc/laser welding: a Level Set approach for weld bead formation and residual stresses

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    1 Numerical modelling of hybrid arc/laser welding: a Level Set approach for weld bead formation.Bellet@mines-paristech.fr ABSTRACT The joining of high thickness steel sheets by means of hybrid Laser/GMAW welding processes of the workpiece borders. Two finite elements models are presented to illustrate: (i) A hybrid arc/laser welding

  7. Influence of welding passes on grain orientation -the example of a multi-pass V-weld.

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Influence of welding passes on grain orientation - the example of a multi-pass V-weld. Jing YE;Abstract The accurate modelling of grain orientations in a weld is important, when accurate ultrasonic test predictions of a welded assembly are needed. To achieve this objective, Electricit de France (EDF

  8. Scan welding: Thermomechanical model and experimental validation

    SciTech Connect (OSTI)

    Fourligkas, N.; Doumanidis, C.C. [Tufts Univ., Medford, MA (United States)

    1996-12-31T23:59:59.000Z

    This article presents a comparative thermomechanical analysis of classical versus the new scan welding methods, that have been recently developed to achieve simultaneous control of multiple weld quality features. Unlike conventional welding with a concentrated heat source in sequential motion, the scan welding torch reciprocates rapidly on dynamic trajectories, and its power is modulated in-process, to provide a regulated heat input distribution on the entire weld surface. The new process was modeled by a real-time analytical, lumped model, consisting of a composite heat source description, double-cell circulation in the weld puddle, dynamic solid conduction and estimation of the mechanical strength of the joint. The process is computationally and experimentally shown to generate a smooth and uniform temperature field, and to deposit the full length of the weld bead simultaneously at a controlled solidification rate. The observed interlacing of grains on the bead interface and the regulated material microstructure yield improved tensile joint strength. The model can be used for design of a closed-loop thermal controller, using temperature feedback from an infrared pyrometer and model-referenced parameter identification.

  9. Modeling of fundamental phenomena in welds

    SciTech Connect (OSTI)

    Zacharia, T.; Vitek, J.M. [Oak Ridge National Lab., TN (United States); Goldak, J.A. [Carleton Univ., Ottawa, Ontario (Canada); DebRoy, T.A. [Pennsylvania State Univ., University Park, PA (United States); Rappaz, M. [Ecole Polytechnique Federale de Lausanne (Switzerland); Bhadeshia, H.K.D.H. [Cambridge Univ. (United Kingdom)

    1993-12-31T23:59:59.000Z

    Recent advances in the mathematical modeling of fundamental phenomena in welds are summarized. State-of-the-art mathematical models, advances in computational techniques, emerging high-performance computers, and experimental validation techniques have provided significant insight into the fundamental factors that control the development of the weldment. The current status and scientific issues in the areas of heat and fluid flow in welds, heat source metal interaction, solidification microstructure, and phase transformations are assessed. Future research areas of major importance for understanding the fundamental phenomena in weld behavior are identified.

  10. Precipitation of sigma and chi phases in ?-ferrite of Type 316FR weld metals

    SciTech Connect (OSTI)

    Chun, Eun Joon, E-mail: ejchun@mapse.eng.osaka-u.ac.jp [Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Baba, Hayato [Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Nishimoto, Kazutoshi [Department of the Application of Nuclear Technology, Fukui University of Technology, Gakuen 3-6-1, Fukui-shi, Fukui 910-8505 (Japan); Saida, Kazuyoshi [Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

    2013-12-15T23:59:59.000Z

    The decomposition behavior and kinetics of ?-ferrite are examined using aging treatments between 873 and 1073 K for Type 316FR stainless steel weld metals with different solidification modes (316FR AF, 316FR FA). The dominant precipitates are sigma, chi, and secondary austenite nucleated at ?-ferrite/austenite interfaces or in the interior of the ferrite grains. These precipitates consume all the ferrite during isothermal aging in both 316FR AF and FA weld metals. Differences in the precipitation behavior (precipitation initiation time and precipitation speed) between weld metals can be explained by i) the degree of Cr and Mo microsegregation within ?-ferrite or austenite near ferrite and ii) the nucleation sites induced due to the solidification mode (AF or FA), such as the ferrite amount. For both weld materials, a JohnsonMehl-type equation can express the precipitation behavior of the sigma + chi phases and quantitatively predict the behavior at the service-exposure temperatures of a fast breed reactor. - Highlights: Precipitation of ? and ? phase in Type 316FR welds (two solidification modes) Different precipitation behaviors: precipitation initiation time and growth speed Johnson-Mehltype equation is the most applicable to the precipitation behaviors Precipitation behaviors are predicted under service conditions of FBRs.

  11. Microstructural analysis of a single pass 2.25% Cr-1.0% Mo steel weld metal with different manganese contents

    SciTech Connect (OSTI)

    Guimares de Souza, Luis Felipe [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca (CEFET-RJ), Av. Maracana, 229, Rio de Janeiro, RJ, 20271-110 (Brazil); Souza Bott, Ivani de [Pontificia Universidade Catolica (PUC-RIO), R. Marques de SaoVicente, 225, Rio de Janeiro, RJ, 22453-900 (Brazil); Ferreira Jorge, Jorge Carlos [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca (CEFET-RJ), Av. Maracana, 229, Rio de Janeiro, RJ, 20271-110 (Brazil); Sauer Guimaraes, Ari [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), Caixa Postal 68.505, Cidade Universitaria, Ilha do Fundao, RJ, 21945-970 (Brazil); Pinheiro Rocha Paranhos, Ronaldo [Universidade Estadual do Norte Fluminense (UENF), Av. Alberto Lamego, 2000, Campos, RJ, 28013-602 (Brazil)]. E-mail: paranhos@uenf.br

    2005-07-15T23:59:59.000Z

    Weld metals of the 2.25% Cr-1.0% Mo type with 0.84%, 1.21% and 2.3% Mn produced by submerged-arc welding were analyzed in the as-welded (AW), post weld heat treatment (PWHT) and PWHT followed by step-cooling (SC) heat treatment conditions. Fracture surface analysis revealed an evolution in the mode of fracture due to Mn content variations and heat treatment conditions, the occurrence of intergranular fracture being observed in welds with 2.30% Mn that were step-cooled. Transmission electron microscopy revealed that the microstructure was predominantly composed of bainite, although martensite was also observed for high Mn contents. A marked carbide precipitation was observed, preferentially at grain boundaries. This could be attributed to the SC heat treatment and associated with the embrittlement. However, the application of a de-embrittlement heat treatment to this step cooled weld metal has proved efficient, because the impact energy levels after this heat treatment surpassed those obtained in the stress relieved condition. This indicates that segregation of impurities to grain boundaries was responsible for the low impact energy levels observed after SC of weld metal containing > 0.84% Mn.

  12. Prediction of Welding Distortion Panagiotis Michaleris and Andrew DeBiccari

    E-Print Network [OSTI]

    Michaleris, Panagiotis

    1 Prediction of Welding Distortion Panagiotis Michaleris and Andrew DeBiccari Edison Welding Institute Columbus, Ohio ABSTRACT. This paper presents a numerical analysis technique for predicting welding induced distortion. The technique combines two dimensional welding simulations with three dimensional

  13. Characterization of microstructure, chemical composition, corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750

    SciTech Connect (OSTI)

    Tavares, S.S.M. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica/PGMEC, Rua Passo da Patria, 156, CEP 24210-240, Niteroi/RJ (Brazil)]. E-mail: ssmtavares@terra.com.br; Pardal, J.M. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica/PGMEC, Rua Passo da Patria, 156, CEP 24210-240, Niteroi/RJ (Brazil); Lima, L.D. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica/PGMEC, Rua Passo da Patria, 156, CEP 24210-240, Niteroi/RJ (Brazil); Bastos, I.N. [Universidade do Estado do Rio de Janeiro (UERJ), Instituto Politecnico (IPRJ), Nova Friburgo/RJ (Brazil); Nascimento, A.M. [Universidade Estadual de Campinas (UNICAMP), Departamento de Engenharia Mecanica, Campinas/SP (Brazil); Souza, J.A. de [Universidade Federal Fluminense, Departamento de Engenharia Mecanica/PGMEC, Rua Passo da Patria, 156, CEP 24210-240, Niteroi/RJ (Brazil)

    2007-07-15T23:59:59.000Z

    The superduplex stainless steels have an austeno-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure improves simultaneously the mechanical properties and corrosion resistance. Welding of these steels is often a critical operation. In this paper we focus on characterization and analysis of a multipass weld joint of UNS S32750 steel prepared using welding conditions equal to industrial standards. The toughness and corrosion resistance properties of the base metal, root pass welded with gas tungsten arc welding, as well as the filler passes, welded with shielded metal arc welding, were evaluated. The microstructure and chemical composition of the selected areas were also determined and correlated to the corrosion and mechanical properties. The root pass was welded with low nickel filler metal and, as a consequence, presented low austenite content and significant precipitation. This precipitation is reflected in the corrosion and mechanical properties. The filler passes presented an adequate ferrite:austenite proportion but, due to their high oxygen content, the toughness was lower than that of the root pass. Corrosion properties were evaluated by cyclic polarization tests in 3.5% NaCl and H{sub 2}SO{sub 4} media.

  14. Vibration welding system with thin film sensor

    DOE Patents [OSTI]

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18T23:59:59.000Z

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  15. GTAW penetration based on electrode tip location versus weld joint center line. [Gas Tungsten Arc Welding (GTAW)

    SciTech Connect (OSTI)

    Daumeyer, G.J. III.

    1992-11-01T23:59:59.000Z

    Gas Tungsten Arc Welding (GTAW) is often the chosen process for final enclosure welds of heat sensitive electrical and electronic product. GTAW is used to produce welds that satisfy design requirements (usually a penetration requirement) and not expose the product to such high heat that would cause unwanted damage. An important variable in the GTAW process is the location of the Electrode tip over the weld joint center line. This study shows the tolerance of positional location over a narrow scope. Using coupons which represent the W88 container weld joint geometry, penetration vs. electrode tip positional location (offset) is investigated. Results indicate a positional location tolerance of [plus minus] 0.008 in. is acceptable. Several different major components (MCS) supporting various weapons programs require low heat input GTA welds. The electrode tip positional location tolerance is determined by each MC's weld joint tolerances and heat sensitivity. For this short study, the weld joint geometry of a container weld was used. These coupons were welded with the specified weld schedule and one additional weld schedule in order to show the relationship based on both travel speed and gap. Multiple coupon welds were made to eliminate error in the results. Within the scope of this research, a positional tolerance of [plus minus] 0.008 in. of the electrode center over the weld joint center is required. For other MCs this tolerance may be tighter or more relaxed depending upon the specific considerations.

  16. Towards Real Time Diagnostics of Hybrid Welding Laser/GMAW

    SciTech Connect (OSTI)

    Timothy Mcjunkin; Dennis C. Kunerth; Corrie Nichol; Evgueni Todorov; Steve Levesque; Feng Yu; Robert Danna Couch

    2013-07-01T23:59:59.000Z

    Methods are currently being developed towards a more robust system real time feedback in the high throughput process combining laser welding with gas metal arc welding. A combination of ultrasonic, eddy current, electronic monitoring, and visual techniques are being applied to the welding process. Initial simulation and bench top evaluation of proposed real time techniques on weld samples are presented along with the concepts to apply the techniques concurrently to the weld process. Consideration for the eventual code acceptance of the methods and system are also being researched as a component of this project. The goal is to detect defects or precursors to defects and correct when possible during the weld process.

  17. Towards real time diagnostics of Hybrid Welding Laser/GMAW

    SciTech Connect (OSTI)

    McJunkin, T. R.; Kunerth, D. C.; Nichol, C. I. [Idaho National Laboratory, Idaho Falls, ID 83415-3570 (United States); Todorov, E.; Levesque, S. [Edison Welding Institute, Columbus, OH (United States)

    2014-02-18T23:59:59.000Z

    Methods are currently being developed towards a more robust system real time feedback in the high throughput process combining laser welding with gas metal arc welding. A combination of ultrasonic, eddy current, electronic monitoring, and visual techniques are being applied to the welding process. Initial simulation and bench top evaluation of proposed real time techniques on weld samples are presented along with the concepts to apply the techniques concurrently to the weld process. Consideration for the eventual code acceptance of the methods and system are also being researched as a component of this project. The goal is to detect defects or precursors to defects and correct when possible during the weld process.

  18. Thermocapillary and arc phenomena in stainless steel welds

    SciTech Connect (OSTI)

    Pierce, S.W.

    1993-10-01T23:59:59.000Z

    Goal was to study effect of power level and distribution on thermocapiilary-induced weld shape and of arc factors on weld shape. Thermocapillarity was apparent in both conduction mode EB welds and GTA welds, particularly in the former. A non-Gaussian arc distribution is suggested for accounting for the differences between the twoss processes. At higher current levels (200--300 A), plasma shear force also contributes to weld shape development. Evidence suggests that thermocapillary flow reversal is not a factor in normal GTA welds; EDB flow reversal occurs only at high power density levels where the keyhole mode is present.

  19. Low Distortion Welded Joints for NCSX

    SciTech Connect (OSTI)

    M. Denault, M Viola, W. England

    2009-02-19T23:59:59.000Z

    The National Compact Stellarator Experiment (NCSX) required precise positioning of the field coils in order to generate suitable magnetic fields. A set of three modular field coils were assembled to form the Half Field-Period Assemblies (HPA). Final assembly of the HPA required a welded shear plate to join individual coils in the nose region due to the geometric limitations and the strength constraints. Each of the modular coil windings was wound on a stainless steel alloy (Stellalloy) casting. The alloy is similar to austenitic 316 stainless steel. During the initial welding trials, severe distortion, of approximately 1/16", was observed in the joint caused by weld shrinkage. The distortion was well outside the requirements of the design. Solutions were attempted through several simultaneous routes. The joint design was modified, welding processes were changed, and specialized heat reduction techniques were utilized. A final joint design was selected to reduce the amount of weld material needed to be deposited, while maintaining adequate penetration and strength. Several welding processes and techniques using Miller Axcess equipment were utilized that significantly reduced heat input. The final assembly of the HPA was successful. Distortion was controlled to 0.012", well within the acceptable design tolerance range of 0.020" over a 3.5 foot length.

  20. Visible Light Emissions during Gas Tungsten Arc Welding and Its Application to Weld

    E-Print Network [OSTI]

    Eagar, Thomas W.

    emission, were also determined. An improved image of the weld pool can be obtained by operating within will require development of new sensor systems. As the "Yelding arc is a harsh environment, noncontacting to control joint tracking and weld E. W. KIM, C. ALLEMAND and T. W. EAGAR are with the Massachusetts

  1. Apparatus for maintaining aligment of a shrinking weld joint in an electron-beam welding operation

    DOE Patents [OSTI]

    Trent, J.B.; Murphy, J.L.

    1980-01-03T23:59:59.000Z

    The invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignement with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a bias means for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base in indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

  2. Apparatus for maintaining alignment of a shrinking weld joint in an electron-beam welding operation

    DOE Patents [OSTI]

    Trent, Jett B. (Knoxville, TN); Murphy, Jimmy L. (Oak Ridge, TN)

    1981-01-01T23:59:59.000Z

    The present invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignment with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a biasing device for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base is indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

  3. automatic arc welding: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    control computer, has been accomplished. n.n. 2 Double-Sided Arc Welding Increases Weld Joint Penetration CiteSeer Summary: this paper proposes increasing the penetration by...

  4. CUTTING -WELDING -HOT WORKS REQUIRED NOTIFICATION TO CUFD

    E-Print Network [OSTI]

    Stuart, Steven J.

    CUTTING - WELDING - HOT WORKS REQUIRED NOTIFICATION TO CUFD Instructions: Fill out this form in its Time for work: Description of Work: Brazing Roofing Sweating WeldingSolderingCutting Other

  5. Friction Stir Spot Welding of Advanced High Strength Steels ...

    Energy Savers [EERE]

    Stir Spot Welding of Advanced High Strength Steels (AHSS) Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) Presentation from the U.S. DOE Office of Vehicle...

  6. Technique to eliminate helium induced weld cracking in stainless steels

    SciTech Connect (OSTI)

    Chin-An Wang; Chin, B.A. [Auburn Univ., AL (United States). Dept. of Materials Engineering; Grossbeck, M.L. [Oak Ridge National Lab., TN (United States)

    1992-12-31T23:59:59.000Z

    Experiments have shown that Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 Mpa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  7. Repair welding of fusion reactor components. Second year technical report

    SciTech Connect (OSTI)

    Chin, B.A.

    1993-05-15T23:59:59.000Z

    Experiments have shown that irradiated Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 MPa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  8. Assessing Exposures to Particulate Matter and Manganese in Welding Fumes

    E-Print Network [OSTI]

    LIU, SA

    2010-01-01T23:59:59.000Z

    helmets. AmericanIndustrialHygieneAssociationJournalwelding. AmericanIndustrialHygieneAssociationJournalelectrodes. American IndustrialHygieneAssociation

  9. Prediction of cooling rate and microstructure in laser spot welds

    E-Print Network [OSTI]

    Cambridge, University of

    during laser spot welding of low alloy steel. A transient heat transfer model that takes into account

  10. Plutonium metal and oxide container weld development and qualification

    SciTech Connect (OSTI)

    Fernandez, R.; Horrell, D.R.; Hoth, C.W.; Pierce, S.W.; Rink, N.A.; Rivera, Y.M.; Sandoval, V.D.

    1996-01-01T23:59:59.000Z

    Welds were qualified for a container system to be used for long-term storage of plutonium metal and oxide. Inner and outer containers are formed of standard tubing with stamped end pieces gas-tungsten-arc (GTA) welded onto both ends. The weld qualification identified GTA parameters to produce a robust weld that meets the requirements of the Department of Energy standard DOE-STD-3013-94, ``Criteria for the Safe Storage of Plutonium Metals and Oxides.``

  11. Modeling of thermomechanical conditions in Sigmajig weldability test

    SciTech Connect (OSTI)

    Feng, Z.; Zacharia, T.; David, S.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1995-08-01T23:59:59.000Z

    A finite element model has been developed to evaluate quantitatively the thermomechanical conditions for weld metal solidification cracking of a nickel based superalloy single-crystal in a laboratory weldability test, namely, the Sigmajig test. The effects of weld pool solidification on the thermal and mechanical behaviors of the specimen were considered. Stress-temperature-location diagrams were constructed to reveal the complex local stress development at the trailing edge of the weld pool. The calculated local stress in the solidification temperature range is used to explain the experimentally observed initiation of solidification cracking of the single-crystal under different welding and loading conditions, based on the material resistance versus the mechanical driving force.

  12. Effect of Post-Weld Heat Treatment on Creep Rupture Properties of Grade 91 Steel Heavy Section Welds

    SciTech Connect (OSTI)

    Li, Leijun

    2012-11-02T23:59:59.000Z

    This project will conduct a systematic metallurgical study on the effect of post-weld heat treatment (PWHT) on the creep rupture properties of P91 heavy section welds. The objective is to develop a technical guide for selecting PWHT parameters, and to predict expected creep-rupture life based on the selection of heat treatment parameters. The project consists of four interdependent tasks: Experimentally and numerically characterize the temperature fields of typical post-weld heat treatment procedures for various weld and joint configurations to be used in Gen IV systems. Characterize the microstructure of various regions, including the weld fusion zone, coarse-grain heat-affected zone, and fine-grain heat affected zone, in the welds that underwent the various welding and PWHT thermal histories. Conduct creep and creep-rupture testing of coupons extracted from actual and physically simulated welds. Establish the relationship among PWHT parameters, thermal histories, microstructure, creep, and creep-rupture properties.

  13. Environmental Conditions Environmental Conditions

    E-Print Network [OSTI]

    Environmental Conditions Environmental Conditions Appendix II The unique geology, hydrology and instream habitat. This chapter examines how environmental conditions in the Deschutes watershed affect, the discussion characterizes the environmental conditions within three watershed areas: the Lower Deschutes

  14. An experimental method for investigating phase transformations in the heat affected zone of welds using synchrotron radiation

    SciTech Connect (OSTI)

    Elmer, J.W.; Wong, J.; Froba, M.; Waide, P.A.; Larson, E.M.

    1995-05-26T23:59:59.000Z

    Although welding is an established technology used in many industrial settings, it is least understand terms of the phases that actually exist, the variation of their spatial disposition with time, and the rate of transformation from one phase to another at various thermal coordinates in the vicinity of the weld. With the availability of high flux and, more recently, high brightness synchrotron x-radiation sources, a number of diffraction and spectroscopic methods have been developed for structural characterization with improved spatial and temporal resolutions to enable in-situ measurements of phases under extreme temperature, pressure and other processing conditions not readily accessible with conventional sources. This paper describes the application of spatially resolved x-ray diffraction (SRXRD) for in-situ investigations of phase transformations in the heat affected zone (HAZ) of fusion welds. Results are presented for gas tungsten (GTA) welds in commercially pure titanium that show the existence of the high temperature bcc {beta}-phase in a 3.3 {plus_minus} 0.3 mm wide HA band adjacent to the liquid weld pool. Phase concentration profiles derived from the SRXRD data further show the co-existence of both the low temperature hcp ({alpha}-phase and the {beta}-phase in the partially, transformed region of the HA. These results represent the first direct observations of solid state phase transformations and mapping of phase boundaries in fusion welds. SRXRD experiments of this type are needed as experimental input for modeling of kinetics of phase transformations and microstructural evolution under the highly non-isothermal conditions produced during welding.

  15. REAL TIME ULTRASONIC ALUMINUM SPOT WELD MONITORING SYSTEM

    SciTech Connect (OSTI)

    Regalado, W. Perez; Chertov, A. M.; Maev, R. Gr. [Institute for Diagnostic Imaging Research, Physics Department, University of Windsor, 292 Essex Hall, 401 Sunset Ave. N9B 3P4 Windsor, Ontario (Canada)

    2010-02-22T23:59:59.000Z

    Aluminum alloys pose several properties that make them one of the most popular engineering materials: they have excellent corrosion resistance, and high weight-to-strength ratio. Resistance spot welding of aluminum alloys is widely used today but oxide film and aluminum thermal and electrical properties make spot welding a difficult task. Electrode degradation due to pitting, alloying and mushrooming decreases the weld quality and adjustment of parameters like current and force is required. To realize these adjustments and ensure weld quality, a tool to measure weld quality in real time is required. In this paper, a real time ultrasonic non-destructive evaluation system for aluminum spot welds is presented. The system is able to monitor nugget growth while the spot weld is being made. This is achieved by interpreting the echoes of an ultrasound transducer located in one of the welding electrodes. The transducer receives and transmits an ultrasound signal at different times during the welding cycle. Valuable information of the weld quality is embedded in this signal. The system is able to determine the weld nugget diameter by measuring the delays of the ultrasound signals received during the complete welding cycle. The article presents the system performance on aluminum alloy AA6022.

  16. CORRECTION OF BUTT-WELDING INDUCED DISTORTIONS BY LASER FORMING

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    CORRECTION OF BUTT-WELDING INDUCED DISTORTIONS BY LASER FORMING Peng Cheng, Andrew J. Birnbaum, Y Egland Technology and Solutions Division Caterpillar Inc. Peoria, IL KEYWORDS Welding, Distortion, Correction, Laser Forming ABSTRACT Welding-induced distortion is an intrinsic phenomenon arising due

  17. Some European Developments in Welding Consumables L. Karlsson

    E-Print Network [OSTI]

    Cambridge, University of

    Some European Developments in Welding Consumables L. Karlsson and H. K. D. H. Bhadeshia* November 1 a selected survey of incisive research on novel welding consumables which contribute to the structural and insight based on metallurgical experience. We congratulate the Japan Welding Society for organising

  18. A PARANETRIC STlJDY OF THE ELECTROSLAG WELDING PROCESS

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) A PARANETRIC STlJDY OF THE ELECTROSLAG WELDING PROCESS by W. S. Ricci and T. W. Eagar conducted on electroslag welds to statistically evaluate the effect of i ndependent process variables upon dependent process responses consisting of heat affected zone size, dilution, form factor, welding speed

  19. Dr. Thomas A. Siewert IN-SPACE WELDING

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) Dr. Thomas A. Siewert IN-SPACE WELDING Visions & Realities presented to Thirtieth Space This paperestablishes the value of having an in-space welding capability and identifies its applications, both near, Plasma Arc, and Laser Beam, are examined against the criteria for an in-space welding system. Research

  20. Electromagnetically and Thermally Driven Flow Phenomena in Electroslag Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) Electromagnetically and Thermally Driven Flow Phenomena in Electroslag Welding A. H. DILAWARI, J for the Electroslag Welding Process. In the formulation, allowance has been made {or both etee- tromagnetic and b in the use of electroslag welding (ESW), particularly for the construction of thick walled pressure vessels

  1. Minimization of welding residual stress and distortion in large structures

    E-Print Network [OSTI]

    Michaleris, Panagiotis

    1 Minimization of welding residual stress and distortion in large structures P. Michaleris at Champaign Urbana, Urbana, IL Abstract Welding distortion in large structures is usually caused by buckling due to the residual stress. In cases where the design is fixed and minimum weld size requirements

  2. Welding residual stresses in ferritic power plant steels

    E-Print Network [OSTI]

    Cambridge, University of

    REVIEW Welding residual stresses in ferritic power plant steels J. A. Francis*1 , H. K. D. H require therefore, an accounting of residual stresses, which often are introduced during welding. To do in the estimation of welding residual stresses in austenitic stainless steels. The progress has been less convincing

  3. .Heat Generation Patterns and Temperature Profiles in_ Electroslag Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    l .Heat Generation Patterns and Temperature Profiles in_ Electroslag Welding ) T. DEBROY, J in the slag and metal phases for an electroslag welding system. It is shown that the current is significantly larger for the electroslag welding process than that of the electroslao refinino process operating

  4. CONFORMAL WELDING AND KOEBE'S THEOREM CHRISTOPHER J. BISHOP

    E-Print Network [OSTI]

    Bishop, Christopher

    CONFORMAL WELDING AND KOEBE'S THEOREM CHRISTOPHER J. BISHOP Abstract. It is well known that not every orientation preserving homeomorphism of the circle to itself is a conformal welding, but in this paper we prove several results which state that every homeomorphism is \\almost" a welding in a precise

  5. Friction Stir Welding John Hinch and John Rudge

    E-Print Network [OSTI]

    Rudge, John

    Friction Stir Welding John Hinch and John Rudge September 11, 2002 1 Introduction Friction Stir Welding is an innovative technique for joining two pieces of metal. A rapidly rotating tool is pushed that a good model of friction stir welding should be able to predict - the power, the force, the temperature

  6. Cinematography of Resistance Spot Welding of Galvanized Steel Sheet

    E-Print Network [OSTI]

    Eagar, Thomas W.

    Cinematography of Resistance Spot Welding of Galvanized Steel Sheet Preweld and postweld current modifications on the resistance spot welding of galvanized steel sheet are analyzed using high phenomena through out the weld process are discussed. In addition. the duration of current modifi cation

  7. Experimental validation of finite element codes for welding deformations

    E-Print Network [OSTI]

    Boyer, Edmond

    Experimental validation of finite element codes for welding deformations H. M. Aarbogha,b, , M Institute for Energy Technology, N-2027 Kjeller, Norway. Abstract A single pass Metal Inert Gas welding which numerical codes quantifying welding stresses can be validated. It includes a mov- ing heat source

  8. Conformal welding and the sewing equations Eric Schippers

    E-Print Network [OSTI]

    Schippers, Eric

    Conformal welding and the sewing equations Eric Schippers Department of Mathematics University of Manitoba Winnipeg Rutgers 2014 Eric Schippers (Manitoba) Conformal welding Rutgers 1 / 41 #12;Introduction Schippers (Manitoba) Conformal welding Rutgers 2 / 41 #12;Introduction Our work in general We began

  9. Apparatus for the concurrent inspection of partially completed welds

    DOE Patents [OSTI]

    Smartt, Herschel B. (Idaho Falls, ID); Johnson, John A. (Idaho Falls, ID); Larsen, Eric D. (Idaho Falls, ID); Bitsoi, Rodney J. (Ririe, ID); Perrenoud, Ben C. (Rigby, ID); Miller, Karen S. (Idaho Falls, ID); Pace, David P. (Idaho Falls, ID)

    2002-01-01T23:59:59.000Z

    An apparatus for the concurrent inspection of partially completed welds is described in which is utilized in combination with a moveable welder for forming a partially completed weld, and an ultrasonic generator mounted on a moveable welder in which is reciprocally moveable along a path of travel which is laterally disposed relative to the partially completed weld.

  10. Actively controlled vibration welding system and method

    DOE Patents [OSTI]

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02T23:59:59.000Z

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  11. Laser assisted arc welding for aluminum alloys

    SciTech Connect (OSTI)

    Fuerschbach, P.W.

    2000-01-01T23:59:59.000Z

    Experiments have been performed using a coaxial end-effector to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project goal is to develop an improved fusion welding process that exhibits both absorption robustness and deep penetration for small scale (<1.5 mm thickness) applications. On aluminum alloys 6061 and 6111, the hybrid process has been shown to eliminate hot cracking in the fusion zone. Fusion zone dimensions for both stainless steel and aluminum were found to be wider than characteristic laser welds, and deeper than characteristic plasma arc welds.

  12. Method and apparatus for welding precipitation hardenable materials

    DOE Patents [OSTI]

    Murray, Jr., Holt (Hopewell, NJ); Harris, Ian D. (Dublin, OH); Ratka, John O. (Cleveland Heights, OH); Spiegelberg, William D. (Parma, OH)

    1994-01-01T23:59:59.000Z

    A method for welding together members consisting of precipitation age hardened materials includes the steps of selecting a weld filler material that has substantially the same composition as the materials being joined, and an age hardening characteristic temperature age threshold below that of the aging kinetic temperature range of the materials being joined, whereby after welding the members together, the resulting weld and heat affected zone (HAZ) are heat treated at a temperature below that of the kinetic temperature range of the materials joined, for obtaining substantially the same mechanical characteristics for the weld and HAZ, as for the parent material of the members joined.

  13. Method and apparatus for welding precipitation hardenable materials

    DOE Patents [OSTI]

    Murray, H. Jr.; Harris, I.D.; Ratka, J.O.; Spiegelberg, W.D.

    1994-06-28T23:59:59.000Z

    A method for welding together members consisting of precipitation age hardened materials includes the steps of selecting a weld filler material that has substantially the same composition as the materials being joined, and an age hardening characteristic temperature age threshold below that of the aging kinetic temperature range of the materials being joined, whereby after welding the members together, the resulting weld and heat affected zone (HAZ) are heat treated at a temperature below that of the kinetic temperature range of the materials joined, for obtaining substantially the same mechanical characteristics for the weld and HAZ, as for the parent material of the members joined. 5 figures.

  14. Method for producing titanium aluminide weld rod

    DOE Patents [OSTI]

    Hansen, Jeffrey S. (Corvallis, OR); Turner, Paul C. (Albany, OR); Argetsinger, Edward R. (Albany, OR)

    1995-01-01T23:59:59.000Z

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

  15. Advanced Ultrasonic Inspection Techniques for General Purpose Heat Source Fueled Clad Closure Welds

    SciTech Connect (OSTI)

    Moyer, M.W.

    2001-01-11T23:59:59.000Z

    A radioisotope thermoelectric generator is used to provide a power source for long-term deep space missions. This General Purpose Heat Source (GPHS) is fabricated using iridium clad vent sets to contain the plutonium oxide fuel pellets. Integrity of the closure weld is essential to ensure containment of the plutonium. The Oak Ridge Y-12 Plant took the lead role in developing the ultrasonic inspection for the closure weld and transferring the inspection to Los Alamos National Laboratory for use in fueled clad inspection for the Cassini mission. Initially only amplitude and time-of-flight data were recorded. However, a number of benign geometric conditions produced signals that were larger than the acceptance threshold. To identify these conditions, a B-scan inspection was developed that acquired full ultrasonic waveforms. Using a test protocol the B-scan inspection was able to identify benign conditions such as weld shield fusion and internal mismatch. Tangential radiography was used to confirm the ultrasonic results. All but two of 29 fueled clads for which ultrasonic B-scan data was evaluated appeared to have signals that could be attributed to benign geometric conditions. This report describes the ultrasonic inspection developed at Y-12 for the Cassini mission.

  16. PINCH WELD TESTING TO SUPPORT CHANGE IN MANUFACTURING OIL AT THE KCP

    SciTech Connect (OSTI)

    Korinko, P; David Maxwell, D

    2008-02-28T23:59:59.000Z

    This task supports the change from an oil mixture termed 50:50 oil (an equal parts mixture of Milpro 634 and Pennex N47) to a new oil mixture (Castrol Illocut 334). This change was necessitated by a KCP vendor no longer supplying the Pennex N47 component of the 50-50. In order to continue production of machined parts, a detailed process was followed to ensure that high quality parts could be manufactured and that the cutting oil selected would provide acceptable human performance characteristics, e.g., skin irritability, smell, etc. A prime consideration in changing the oil was that no apparent change in the pinch weldability of the fill stems fabricated using the new oil and process parameters, if any, be observed. A two part approach, as detailed in the plan shown in Appendix B, was used to qualify the effect of the process on pinch weld characteristics. In the first phase, ref. 1., the weld parameter window was defined using fill stems made from 304L, 21-6-9, and 316 stainless steel. These weld conditions were then subsequently used for the Castrol Illocut 334 machined fill stems. The results of this activity are reported in this document. A follow-on task of welding in the facility was requested by one of the design agencies and this will be completed and reported separately.

  17. Fluor Hanford Nuclear Material Stabilization Project Welding Manual

    SciTech Connect (OSTI)

    BERKEY, J.R.

    2000-10-20T23:59:59.000Z

    The purpose of this section of the welding manual is to: (1) Provide a general description of the major responsibilities of the organizations involved with welding. (2) Provide general guidance concerning the application of codes related to welding. This manual contains requirements for welding for all Fluor Hanford (FH) welding operators working on the W460 Project, in the Plutonium Finishing Plant (PFP) at the U. S. Department of Energy (DOE) Hanford facilities. These procedures and any additional requirements for these joining processes can be used by all FH welding operators that are qualified. The Welding Procedure Specifications (WPS) found in this document were established from Procedure Qualification Records (PQR) qualified by FH specifically for the W460 Project. PQRs are permanent records of the initial testing and qualification program and are used to backup, and support, the WPS. The identification numbers of the supporting PQR(s) are recorded on each WPS. All PQRs are permanently stored under the supervision of the Fluor Hanford Welding Engineer (FHWE). New PQRs and WPSs will continue to be developed as necessary. The qualification of welders, welding operators and welding procedures will be performed for FH under supervision and concurrent of the FHWE. All new welding procedures to be entered in this manual or welder personnel to be added to the welder qualification database, shall be approved by the FHWE.

  18. Residual stresses in weld overlay tubes: A finite element study

    SciTech Connect (OSTI)

    Taljat, B.; Zacharia, T.; Wang, X.L.; Keiser, J.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Feng, Z. [Edison Welding Inst., Columbus, OH (United States); Jirinec, M.J. [Welding Services, Inc., Norcross, GA (United States)

    1997-01-03T23:59:59.000Z

    Residual stresses and strains in a tube with circumferential weld overlay were analyzed by the finite element (FE) method. The objective of this work was to develop and verify a FE model, to determine the magnitude and distribution of residual stresses in the weld overlay tube, and to evaluate the significance of two contributing factors to residual stress: (1) difference in material properties between tube and weld material, and (2) thermal gradients in the weld. An axisymmetric FE model was developed to simulate the circumferential two-layer welding process of alloy 625 overlay on SA210 tube. The first layer was modeled as a gas metal arc welding process with filler metal, whereas the autogenous gas tungsten arc welding process was modeled for the second layer. Neutron diffraction technique was used to experimentally determine residual elastic strains in the weld overlay tube. Comparison with the FE results shows overall good agreement. Both the experimental and FE results show high compressive stresses at the inside tube surface and high tensile stresses in the weld overlay. This suggests that weld overlay may be used to relieve tensile or produce compressive stresses at the inside tube surface, which is significant for applications where crack initiation is found at the root pass of the joining weld.

  19. Modeling of Heat and Mass Transfer in Fusion Welding

    SciTech Connect (OSTI)

    Zhang, Wei [ORNL

    2011-01-01T23:59:59.000Z

    In fusion welding, parts are joined together by melting and subsequent solidification. Although this principle is simple, complex transport phenomena take place during fusion welding, and they determine the final weld quality and performance. The heat and mass transfer in the weld pool directly affect the size and shape of the pool, the solidification microstructure, the formation of weld defects such as porosity and humping, and the temperature distribution in the fusion zone and heat-affected zone (HAZ). Furthermore, the temperature evolution affects the kinetics and extent of various solid-state phase transformations, which in turn determine the final weld microstructure and mechanical properties. The formation of residual stresses and distortion originates from the thermal expansion and contraction during welding heating and cooling, respectively.

  20. Method for the concurrent ultrasonic inspection of partially completed welds

    DOE Patents [OSTI]

    Johnson, John A. (Idaho Falls, ID); Larsen, Eric D. (Idaho Falls, ID); Miller, Karen S. (Idaho Falls, ID); Smartt, Herschel B. (Idaho Falls, ID); McJunkin, Timothy R. (Idaho Falls, ID)

    2002-01-01T23:59:59.000Z

    A method for the concurrent ultrasonic inspection of partially completed welds is disclosed and which includes providing a pair of transducers which are individually positioned on the opposite sides of a partially completed weld to be inspected; moving the transducers along the length of and laterally inwardly and outwardly relative to the partially completed weld; pulsing the respective transducers to produce an ultrasonic signal which passes through or is reflected from the partially completed weld; receiving from the respective transducers ultrasonic signals which pass through or are reflected from the partially completed welds; and analyzing the ultrasonic signal which has passed through or is reflected from the partially completed weld to determine the presence of any weld defects.

  1. Intermetallic alloy welding wires and method for fabricating the same

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    1996-01-01T23:59:59.000Z

    Welding wires for welding together intermetallic alloys of nickel aluminides, nickel-iron aluminides, iron aluminides, or titanium aluminides, and preferably including additional alloying constituents are fabricated as two-component, clad structures in which one component contains the primary alloying constituent(s) except for aluminum and the other component contains the aluminum constituent. This two-component approach for fabricating the welding wire overcomes the difficulties associated with mechanically forming welding wires from intermetallic alloys which possess high strength and limited ductilities at elevated temperatures normally employed in conventional metal working processes. The composition of the clad welding wires is readily tailored so that the welding wire composition when melted will form an alloy defined by the weld deposit which substantially corresponds to the composition of the intermetallic alloy being joined.

  2. Intermetallic alloy welding wires and method for fabricating the same

    DOE Patents [OSTI]

    Santella, M.L.; Sikka, V.K.

    1996-06-11T23:59:59.000Z

    Welding wires for welding together intermetallic alloys of nickel aluminides, nickel-iron aluminides, iron aluminides, or titanium aluminides, and preferably including additional alloying constituents are fabricated as two-component, clad structures in which one component contains the primary alloying constituent(s) except for aluminum and the other component contains the aluminum constituent. This two-component approach for fabricating the welding wire overcomes the difficulties associated with mechanically forming welding wires from intermetallic alloys which possess high strength and limited ductilities at elevated temperatures normally employed in conventional metal working processes. The composition of the clad welding wires is readily tailored so that the welding wire composition when melted will form an alloy defined by the weld deposit which substantially corresponds to the composition of the intermetallic alloy being joined. 4 figs.

  3. Welding and Weldability of Thorium-Doped Iridium Alloys

    SciTech Connect (OSTI)

    David, S.A.; Ohriner, E.K.; King, J.F.

    2000-03-12T23:59:59.000Z

    Ir-0.3%W alloys doped with thorium are currently used as post-impact containment material for radioactive fuel in thermoelectric generators that provide stable electrical power for a variety of outer planetary space exploration missions. Welding and weldability of a series of alloys was investigated using arc and laser welding processes. Some of these alloys are prone to severe hot-cracking during welding. Weldability of these alloys was characterized using Sigmajig weldability test. Hot-cracking is influenced to a great extent by the fusion zone microstructure and composition. Thorium content and welding atmosphere were found to be very critical. The weld cracking behavior in these alloys can be controlled by modifying the fusion zone microstructure. Fusion zone microstructure was found to be controlled by welding process, process parameters, and the weld pool shape.

  4. Narrow gap welding with the hot wire GTA process

    SciTech Connect (OSTI)

    Cook, G.E.; Levick, P.C.

    1985-08-01T23:59:59.000Z

    Narrow gap welding offers the promise of dramatically improved weld completion rates and reduced heat input for welding of butt joints in materials of 10 mm (0.4 in.) section thickness and larger. Techniques for successful welding of narrow gap joint preparations have been discussed in the literature for approximately twenty years, with the majority of these based on the consumable electrode processes. Gas tungsten arc welding with cold wire filler addition has been shown to be capable of narrow gap welding although limited deposition rate capability has not made this a competitive alternative. The GTAW process offers the advantages of superior penetration control for one-sided welding of butt joints, as well as the potential for reducing incomplete fusion defects. The addition of hot wire filler metal to the gas tungsten arc provides an attractive alternative that combines high deposition rate capability and independent control of heat input.

  5. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder Metallurgy Produced Titanium Alloys

    SciTech Connect (OSTI)

    Muth, Thomas R [ORNL; Yamamoto, Yukinori [ORNL; Frederick, David Alan [ORNL; Contescu, Cristian I [ORNL; Chen, Wei [ORNL; Lim, Yong Chae [ORNL; Peter, William H [ORNL; Feng, Zhili [ORNL

    2013-01-01T23:59:59.000Z

    ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

  6. Theoretical analysis of weld pool behavior in the pulsed current Gas Tungsten Arc Welding (GTAW) process

    SciTech Connect (OSTI)

    Tsai, C.L. (Ohio State Univ., Columbus (United States)); Hou, C.A. (Howard Univ., Washington, DC (United States))

    1988-02-01T23:59:59.000Z

    A general three-dimensional, closed-form welding heat-flow solution, which is capable of analyzing thermal behavior of the weldment in its transient state and/or under time-dependent power change during welding, is presented. The analytical model utilizes the finite heat source theory with a Gaussian distribution and also considers the effects of finite plate thickness. The numerical values of the solution are calculated using the computational schemes on a minicomputer. In this paper the welding parameters of the pulsed current Gas Tungsten Arc Welding (GTAW) were studied using the solution. Two sets of pulsation parameters were analyzed and their sensitivity to the heat input control were evaluated.

  7. Gas metal arc welding of duplex stainless steel using flux cored wire

    SciTech Connect (OSTI)

    Maruyama, T.; Ogawa, T.; Nishiyama, S.; Ushijima, A.; Yamashita, K. [Kobe Steel, Ltd., Fujisawa (Japan)

    1994-12-31T23:59:59.000Z

    The effect of chemical compositions and welding parameters on pitting corrosion resistance and notch toughness of duplex stainless steel weld metals by FCAW was investigated. And the effect of welding parameters on hot cracking susceptibility of the FCAW weld metals was also studied. Pitting corrosion resistance was improved with the increase of Cr, Mo and N content in the weld metal, and it was also proved that the corrosion resistance was greatly affected by welding heat input. Hot cracking susceptibility of the weld metal was increased with the increase of welding current and welding speed.

  8. CHANGES IN SOLIDIFICATION MODE, AND THE MEASUREMENT OF COOLING RATES FOLLOWING SOLIDIFICATION DURING ARC WELDING

    E-Print Network [OSTI]

    Cambridge, University of

    SOLIDIFICATION DURING ARC WELDING 2.1 INTRODUCTION The solidification process in a weld pool has been shown to have a considerable in- fluence upon the properties of the resultant weld. It influences elements, and hence the homogeneity of the weld. Previous work on the cooling behaviour of welds (Garland

  9. Department of Industrial Engineering Spring 2013 Corle Building Systems Submerged Arc Welding Machine

    E-Print Network [OSTI]

    Demirel, Melik C.

    Welding Machine Overview Due to the location of the two weld heads with respect to the ground shoes, the machine is unable to weld approximately the first 16 inches and final 12 inches of the I-beam. These sections must be hand welded later in the fabrication process. This hand welding process is inefficient

  10. Costing of Joining Methods -Arc Welding Costs

    E-Print Network [OSTI]

    Colton, Jonathan S.

    Costing of Joining Methods - Arc Welding Costs ver. 1 ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2009 1 #12;OverviewOverview Cost components Estimation of costsEstimation of costs Examples ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2009 2 #12;Cost

  11. Capacitor discharge process for welding braided cable

    DOE Patents [OSTI]

    Wilson, Rick D. (Corvallis, OR)

    1995-01-01T23:59:59.000Z

    A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically conductive member; and (f) moving the cathode fixture towards the anode fixture until the ignition projection of the electrically conductive member contacts the end portion of the braided cable thereby allowing the capacitor bank to discharge through the electrically conductive member and through the braided cable and causing the electrically conductive member to be welded to the braided cable via capacitor discharge action.

  12. CRAD, Welding, Cutting and Brazing Assessment Plan

    Broader source: Energy.gov [DOE]

    This assessment is to verify hot work requirements associated with welding, cutting, burning, brazing, grinding and other spark- or flame-producing operations have been implemented. Verify that the requirements implemented are appropriate for preventing loss of life and property from fire, and personal injury from contact with or exposure to molten metals, vapors, radiant energy, injurious rays and sparks.

  13. PROTOCOL FOR EXAMINATION OF THE INNER CAN CLOSURE WELD REGION FOR 3013 DE CONTAINERS

    SciTech Connect (OSTI)

    Mickalonis, J.

    2014-09-16T23:59:59.000Z

    The protocol for the examination of the inner can closure weld region (ICCWR) for 3013 DE containers is presented within this report. The protocol includes sectioning of the inner can lid section, documenting the surface condition, measuring corrosion parameters, and storing of samples. This protocol may change as the investigation develops since findings may necessitate additional steps be taken. Details of the previous analyses, which formed the basis for this protocol, are also presented.

  14. Determination of welding fume size with time using E7018 electrodes and A131B base metal

    E-Print Network [OSTI]

    Owen, Richard James

    1976-01-01T23:59:59.000Z

    . 81 0. 14 0. 70 0. 06 0. 64 0. 25 0. 42 0. 83 mglottie velocity 150. Thermal agglomeration is enhanced by the turbulent conditions from the heat generated by the welding process. Not only are the fumes themselves hot, but the air in which...DETERMINATION OF WELDING FUME SIZE WITH TIME USING E7018 ELECTRODES AND A131B BASE METAL A Thesis by RICHARD JAMES OWEN Submitted to the Graduate College of Texas AILM University in partial fulfillment of the requirement for the degree...

  15. On-line weld penetration detection and control in automated gas tungsten arc welding. Ph.D. Thesis

    SciTech Connect (OSTI)

    Banerjee, P.

    1994-01-01T23:59:59.000Z

    The present work was undertaken to study the feasibility of monitoring and controlling weld penetration variations in real-time using an infrared detector. Weld penetration variations induced on mild steel plates were examined with an infrared detector and the acquired data analyzed to detect weld penetration variations using a mathematical analysis. Selected weld penetration indicators were developed and used to demonstrate on-line weld penetration control. A three-dimensional solid-state, transient heat transfer model was also developed to help identify key changes in thermal distributions which could be used as weld penetration indicators. A transient three-dimensional heat transfer model was used to solve the differential energy balance for the GTA welding process. The computed temperatures obtained from the model were used to determine the variation of the isothermal map, surface temperature profile and temperature gradient with weld penetration. Good agreement between experimental and computed indicators was obtained. Gas tungsten arc welds were performed on steel plates with intentionally introduced defects such as sudden thickness changes and minor element content changes. Extensive mathematical analysis helped correlate weld penetration variations to parameters such as the peak infrared intensity, intensity gradient over a fixed distance, intensity gradient at the inflection points in the first differential of the intensity profile (linescan), computed width of the weld pool, intensity gradient at a point in the weld pool, area enclosed by the linescan and area enclosed by the linescan after compensating for background illumination. The shape of the weld pool front was also determined from a differential analysis of the infrared data. Inconsistent behavior of some weld penetration indicators led to their elimination from the selection process for the best error signal.

  16. Non-Vacuum Electron Beam Welding

    SciTech Connect (OSTI)

    Hershcovitch, Ady

    2007-01-31T23:59:59.000Z

    Original objectives of CRADA number BNL-01-03 between BNL and Acceleron, Inc., were to further develop the Plasma Window concept (a BNL invention covered by US Patent number 5,578,831), mate the Plasma Window to an existing electron beam welder to perform in-air electron beam welding, and mount the novel nonvacuum electron beam welder on a robot arm. Except for the last objective, all other goals were met or exceeded. Plasma Window design and operation was enhanced during the project, and it was successfully mated to a conventional4 kW electron beam welder. Unprecedented high quality non-vacuum electron beam . welding was demonstrated. Additionally, a new invention the Plasma Shield (US Patent number 7,075,030) that chemically and thermally shields a target object was set forth. Great interest in the new technology was shown by a number of industries and three arcs were sold for experimental use. However, the welding industry requested demonstration of high speed welding, which requires 100 kW electron beam welders. The cost of such a welder involved the need for additional funding. Therefore, some of the effort was directed towards Plasma Shield development. Although relatively a small portion of the R&D effort was spent on the Plasma Shield, some very encouraging results were obtained. Inair Plasma Shield was demonstrated. With only a partial shield, enhanced vacuum separation and cleaner welds were realized. And, electron beam propagation in atmosphere improved by a factor of about 3. Benefits to industry are the introduction of two new technologies. BNL benefited from licensing fee cash, from partial payment for employee salary, and from a new patent In addition to financial benefits, a new technology for physics studies was developed. Recommendations for future work are to develop an under-water plasma shield, perform welding with high-power electron beam:s, carry out other plasma shielded electron beam and laser processes. Potential benefits from further R&D are that various processes involving electron ion and laser beams that have now restrictions can, with the Plasma Shield be performed in practically any environment. For example, electron beam and laser welding can be performed under water, as well as, in situ repair of ship and nuclear reactor components. The plasma shield results in both thermal (since the plasma is hotter than the environment) and chemical shielding. The latter feature brings about in-vacuum process purity out of vacuum, and the thermal shielding aspect results in higher production rates.

  17. In mold laser welding for high precision polymer based optical components

    SciTech Connect (OSTI)

    Oliveira, N., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt; Pontes, A. J., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt [IPC - Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, 4800-058 Guimares (Portugal)

    2014-05-15T23:59:59.000Z

    To assemble a complete subsystem as a rear lamp, is necessary to have different machines and to perform several tasks. This necessity obliges the companies to have large structures to support all the assembling process. These huge structures are very costly and have as a consequence the reduction of the competitiveness of the companies. The process presented in this document has the intention of reducing the number of tasks needed to produce the final subsystem/product. To achieve this goal were combined several technologies, as in-mould assembling, laser welding and LEDs (light-emitting diode). One of the advantages of this process was the utilization of only one injection molding machine with three injection units to do all the assembling process. To achieve the main objective, firstly, the rear lamp was designed according to with the legislation of UNECE Vehicle Regulations - 1958 Agreements; Regulation No. 50 -Rev.2 - Position lamps, stop lamps, direction indicators for motorcycles. Posterior several polymeric materials were studied at different levels. Initial were studied several concentrations of carbon nanotubes mixed with PC (polycarbonate). This had the objective of determine, if these materials are suitable to conduct the necessary electric current to turn on the different LEDs. One of the main advantages of this process is the use of the laser transmission welded process. Since, with this welding technology is possible reduce the complexity of the final part. To understand the potentialities of this technology a combination of two materials was studied. The studied showed that all materials presented a high transparency to the laser beam. In terms of weld process, the study showed that the best welding conditions are the lowest velocity, diameter and power. With these studies was possible conclude that this new process is suitable to be implemented at the industrial level.

  18. Remote Welding, NDE and Repair of DOE Standardized Canisters

    SciTech Connect (OSTI)

    Eric Larsen; Art Watkins; Timothy R. McJunkin; Dave Pace; Rodney Bitsoi

    2006-05-01T23:59:59.000Z

    The U.S. Department of Energy (DOE) created the National Spent Nuclear Fuel Program (NSNFP) to manage DOEs spent nuclear fuel (SNF). One of the NSNFPs tasks is to prepare spent nuclear fuel for storage, transportation, and disposal at the national repository. As part of this effort, the NSNFP developed a standardized canister for interim storage and transportation of SNF. These canisters will be built and sealed to American Society of Mechanical Engineers (ASME) Section III, Division 3 requirements. Packaging SNF usually is a three-step process: canister loading, closure welding, and closure weld verification. After loading SNF into the canisters, the canisters must be seal welded and the welds verified using a combination of visual, surface eddy current, and ultrasonic inspection or examination techniques. If unacceptable defects in the weld are detected, the defective sections of weld must be removed, re-welded, and re-inspected. Due to the high contamination and/or radiation fields involved with this process, all of these functions must be performed remotely in a hot cell. The prototype apparatus to perform these functions is a floor-mounted carousel that encircles the loaded canister; three stations perform the functions of welding, inspecting, and repairing the seal welds. A welding operator monitors and controls these functions remotely via a workstation located outside the hot cell. The discussion describes the hardware and software that have been developed and the results of testing that has been done to date.

  19. INT. 1. CONTROL, 1993, VOL. 58, No.2, 337-348 Necessary and sufficient conditions under which an H2 optimal

    E-Print Network [OSTI]

    Benmei, Chen

    optimal control problem has a unique solution BEN M. CHENt and ALl SABERI:!: 1 A set of necessary and Moore 1989, Fleming and Rishel 1975, Geerts 1989, Kailath 1974, Kwakernaak and Sivan 1972, Saberi.00 @ 1993 Taylor & Francis LId #12;338 B. M. Chen and A. Saberi class of singular H roptimization problems

  20. 17 The Intelligent Welding Gun: Augmented Reality for Experimental Vehicle Construction

    E-Print Network [OSTI]

    Bruegge, Bernd

    17 The Intelligent Welding Gun: Augmented Reality for Experimental Vehicle Construction Florian presents the prototypical design and implementation of an Intelligent Welding Gun to help welders welding scenario and the identified system requirements is followed by a thorough exploration

  1. EFFECTS OF WELDING ON WELDMENT MECHANICAL PERFORMANCE IN TWO AUSTENITIC STEELS

    E-Print Network [OSTI]

    Strum, M.J.

    2010-01-01T23:59:59.000Z

    Progress, Jan. 1979, p. 76. Welding Journal, June 1976, p .G.A. Ratz: Aug. 1968. C. Syn, Welding Research Council (WRC)Thesis, LBL-9208, May 1979. Welding Journal, July 1971, p.

  2. Fabrication Flaw Density and Distribution In Repairs to Reactor Pressure Vessel and Piping Welds

    SciTech Connect (OSTI)

    GJ Schuster, FA Simonen, SR Doctor

    2008-04-01T23:59:59.000Z

    The Pacific Northwest National Laboratory is developing a generalized fabrication flaw distribution for the population of nuclear reactor pressure vessels and for piping welds in U.S. operating reactors. The purpose of the generalized flaw distribution is to predict component-specific flaw densities. The estimates of fabrication flaws are intended for use in fracture mechanics structural integrity assessments. Structural integrity assessments, such as estimating the frequency of loss-of-coolant accidents, are performed by computer codes that require, as input, accurate estimates of flaw densities. Welds from four different reactor pressure vessels and a collection of archived pipes have been studied to develop empirical estimates of fabrication flaw densities. This report describes the fabrication flaw distribution and characterization in the repair weld metal of vessels and piping. This work indicates that large flaws occur in these repairs. These results show that repair flaws are complex in composition and sometimes include cracks on the ends of the repair cavities. Parametric analysis using an exponential fit is performed on the data. The relevance of construction records is established for describing fabrication processes and product forms. An analysis of these records shows there was a significant change in repair frequency over the years when these components were fabricated. A description of repair flaw morphology is provided with a discussion of fracture mechanics significance. Fabrication flaws in repairs are characterized using optimized-access, high-sensitivity nondestructive ultrasonic testing. Flaw characterizations are then validated by other nondestructive evaluation techniques and complemented by destructive testing.

  3. Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds

    SciTech Connect (OSTI)

    Badji, Riad [LPMTM-CNRS- Universite Paris 13, 99, av. J.B. Clement, 93430 Villetaneuse (France)], E-mail: riadbadji1@yahoo.fr; Bouabdallah, Mabrouk [Ecole Nationale Polytechnique, 10, Avenue Hassan Badi, BP 182, El Harrach (Algeria); Bacroix, Brigitte; Kahloun, Charlie [LPMTM-CNRS- Universite Paris 13, 99, av. J.B. Clement, 93430 Villetaneuse (France); Belkessa, Brahim; Maza, Halim [Welding and NDT research Centre, B.P 64, Cheraga (Algeria)

    2008-04-15T23:59:59.000Z

    The phase transformations and mechanical behaviour during welding and subsequent annealing treatment of 2205 duplex stainless steel have been investigated. Detailed microstructural examination showed the presence of higher ferrite amounts in the heat affected zone (HAZ), while higher amounts of austenite were recorded in the centre region of the weld metal. Annealing treatments in the temperature range of 800-1000 deg. C resulted in a precipitation of {sigma} phase and M{sub 23}C{sub 6} chromium carbides at the {gamma}/{delta} interfaces that were found to be preferential precipitation sites. Above 1050 deg. C, the volume fraction of {delta} ferrite increases with annealing temperature. The increase of {delta} ferrite occurs at a faster rate in the HAZ than in the base metal and fusion zone. Optimal mechanical properties and an acceptable ferrite/austenite ratio throughout the weld regions corresponds to annealing at 1050 deg. C. Fractographic examinations showed that the mode of failure changed from quasi-cleavage fracture to dimple rupture with an increase in the annealing temperature from 850 to 1050 deg. C.

  4. Effect of Pulsed Nd: YAG Laser Powers On 304 Stainless Steel Welding

    SciTech Connect (OSTI)

    Candan, L.; Demir, A.; Akman, E. [University of Kocaeli, Laser Technologies Research and Application Center, Kocaeli (Turkey)

    2007-04-23T23:59:59.000Z

    In this study, optimum welding parameters are obtained for 1mm thickness type 304 stainless steel welding using the Lumonics JK760TR pulsed Nd:YAG laser. The influences of laser welding parameters such as pulse duration, focal position, frequency, laser power, welding speed, and shielding gas (N2) pressure on penetration defining welding quality are investigated. Also comparisons of overlap ratios are presented between theory and experiment for pulse duration, frequency and welding speed.

  5. Apparatus for the concurrent ultrasonic inspection of partially completed welds

    DOE Patents [OSTI]

    Johnson, John A. (Idaho Falls, ID)

    2000-01-01T23:59:59.000Z

    An apparatus for the concurrent nondestructive evaluation of partially completed welds is described and which is used in combination with an automated welder and which includes an ultrasonic signal generator mounted on the welder and which generates an ultrasonic signal which is directed toward one side of the partially completed welds; an ultrasonic signal receiver mounted on the automated welder for detecting ultrasonic signals which are transmitted by the ultrasonic signal generator and which are reflected or diffracted from one side of the partially completed weld or which passes through a given region of the partially completed weld; and an analysis assembly coupled with the ultrasonic signal receiver and which processes the ultrasonic signals received by the ultrasonic signal receiver to identify welding flaws in the partially completed weld.

  6. Conditioned stochastic differential equations: theory, examples and ...

    E-Print Network [OSTI]

    2002-07-03T23:59:59.000Z

    Keywords: Brownian bridge; Conditioning; Initial enlargement of filtration; Exponential generalization of. Pitman's 2M-X theorem; Filtering; Portfolio optimization.

  7. An investigation of residual stress in welded joints

    E-Print Network [OSTI]

    Moffat, William Hugh

    1951-01-01T23:59:59.000Z

    . flummery and Conclusions VII. '-. &uggested Procedure for I"uture Investigation 18 o i' VIII. ? . Ppendix IX. Bibliography LIST OP EIGURES Ro. Title Page 1. 'welded Plates snd Gptical Gage Used by Soulton and Martin ~ ~ 6 2. Dr. Rao~s Method... AN INVESTIGATION OF RESIDUAL STRESS IN WELDED JOINTS INTRODUCTION The object of the research reported in this paper was to investigate the magnitude of transverse and longi- tudial residual stress in a welded Joint. These are the stresses in a direction...

  8. An investigation of residual stress in welded joints

    E-Print Network [OSTI]

    Moffat, William Hugh

    1951-01-01T23:59:59.000Z

    . flummery and Conclusions VII. '-. &uggested Procedure for I"uture Investigation 18 o i' VIII. ? . Ppendix IX. Bibliography LIST OP EIGURES Ro. Title Page 1. 'welded Plates snd Gptical Gage Used by Soulton and Martin ~ ~ 6 2. Dr. Rao~s Method... AN INVESTIGATION OF RESIDUAL STRESS IN WELDED JOINTS INTRODUCTION The object of the research reported in this paper was to investigate the magnitude of transverse and longi- tudial residual stress in a welded Joint. These are the stresses in a direction...

  9. On-Line Weld NDE with IR Thermography

    Broader source: Energy.gov (indexed) [DOE]

    (NDE) technology for resistance spot weld (RSW) quality monitoring based on infrared (IR) thermography that can be adopted reliably and cost-effectively in high-volume...

  10. Friction Stir Spot Welding of Advanced High Strength Steels II...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Steels II Friction Stir Spot Welding of Advanced High Strength Steels II 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer...

  11. Friction Stir Spot Welding of Advanced High Strength Steels ...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    does not contain any proprietary or confidential information Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) (13056 ORNL, 13055 PNNL) Friction Stir Spot...

  12. Fracture of welded aluminum thin-walled structures

    E-Print Network [OSTI]

    Zheng, Li, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    A comprehensive methodology was developed in the thesis for damage prediction of welded aluminum thin-walled structures, which includes material modeling, calibration, numerical simulation and experimental verification. ...

  13. Weld monitor and failure detector for nuclear reactor system

    DOE Patents [OSTI]

    Sutton, Jr., Harry G. (Mt. Lebanon, PA)

    1987-01-01T23:59:59.000Z

    Critical but inaccessible welds in a nuclear reactor system are monitored throughout the life of the reactor by providing small aperture means projecting completely through the reactor vessel wall and also through the weld or welds to be monitored. The aperture means is normally sealed from the atmosphere within the reactor. Any incipient failure or cracking of the weld will cause the environment contained within the reactor to pass into the aperture means and thence to the outer surface of the reactor vessel where its presence is readily detected.

  14. Ductile filler metal alloys for welding nickel aluminide alloys

    DOE Patents [OSTI]

    Santella, Michael L. (Knoxville, TN); McNabb, Jeffrey D. (Lenoir City, TN); Sikka, Vinod K. (Oak Ridge, TN)

    2003-04-08T23:59:59.000Z

    Nickel aluminum alloys are welded utilizing a nickel based alloy containing zirconium but substantially free of titanium and niobium which reduces the tendency to crack.

  15. APLAIR partners with ORNL to commercialize weld inspection technology...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    technology developed by the Department of Energy's Oak Ridge National Laboratory. The automotive industry relies heavily on resistance spot welding in the fabrication and...

  16. New Weld Process Increases Efficiency of Automotive Manufacturing...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Technologies Office (VTO) researchers at ORNL developed a non-destructive, infrared thermography-based system for evaluating weld quality. The new process enables automotive...

  17. A dimensionless parameter model for arc welding processes

    SciTech Connect (OSTI)

    Fuerschbach, P.W.

    1994-12-31T23:59:59.000Z

    A dimensionless parameter model previously developed for C0{sub 2} laser beam welding has been shown to be applicable to GTAW and PAW autogenous arc welding processes. The model facilitates estimates of weld size, power, and speed based on knowledge of the material`s thermal properties. The dimensionless parameters can also be used to estimate the melting efficiency, which eases development of weld schedules with lower heat input to the weldment. The mathematical relationship between the dimensionless parameters in the model has been shown to be dependent on the heat flow geometry in the weldment.

  18. Subterranean barriers including at least one weld

    DOE Patents [OSTI]

    Nickelson, Reva A.; Sloan, Paul A.; Richardson, John G.; Walsh, Stephanie; Kostelnik, Kevin M.

    2007-01-09T23:59:59.000Z

    A subterranean barrier and method for forming same are disclosed, the barrier including a plurality of casing strings wherein at least one casing string of the plurality of casing strings may be affixed to at least another adjacent casing string of the plurality of casing strings through at least one weld, at least one adhesive joint, or both. A method and system for nondestructively inspecting a subterranean barrier is disclosed. For instance, a radiographic signal may be emitted from within a casing string toward an adjacent casing string and the radiographic signal may be detected from within the adjacent casing string. A method of repairing a barrier including removing at least a portion of a casing string and welding a repair element within the casing string is disclosed. A method of selectively heating at least one casing string forming at least a portion of a subterranean barrier is disclosed.

  19. FRACTURE MECHANICS APPROACH TO ESTIMATE FATIGUE LIVES OF WELDED LAP-SHEAR SPECIMENS

    SciTech Connect (OSTI)

    Lam, P.; Michigan, J.

    2014-04-25T23:59:59.000Z

    A full range of stress intensity factor solutions for a kinked crack is developed as a function of weld width and the sheet thickness. When used with the associated main crack solutions (global stress intensity factors) in terms of the applied load and specimen geometry, the fatigue lives can be estimated for the laser-welded lap-shear specimens. The estimations are in good agreement with the experimental data. A classical solution for an infinitesimal kink is also employed in the approach. However, the life predictions tend to overestimate the actual fatigue lives. The traditional life estimations with the structural stress along with the experimental stress-fatigue life data (S-N curve) are also provided. In this case, the estimations only agree with the experimental data under higher load conditions.

  20. Neutron Diffraction Residual Strain Tensor Measurements Within The Phase IA Weld Mock-up Plate P-5

    SciTech Connect (OSTI)

    Hubbard, Camden R [ORNL

    2011-09-01T23:59:59.000Z

    Oak Ridge National Laboratory (ORNL) has worked with NRC and EPRI to apply neutron and X-ray diffraction methods to characterize the residual stresses in a number of dissimilar metal weld mockups and samples. The design of the Phase IA specimens aimed to enable stress measurements by several methods and computational modeling of the weld residual stresses. The partial groove in the 304L stainless steel plate was filled with weld beads of Alloy 82. A summary of the weld conditions for each plate is provided in Table 1. The plates were constrained along the long edges during and after welding by bolts with spring-loaded washers attached to the 1-inch thick Al backing plate. The purpose was to avoid stress relief due to bending of the welded stainless steel plate. The neutron diffraction method was one of the methods selected by EPRI for non-destructive through thickness strain and stress measurement. Four different plates (P-3 to P-6) were studied by neutron diffraction strain mapping, representing four different welding conditions. Through thickness neutron diffraction strain mappings at NRSF2 for the four plates and associated strain-free d-zero specimens involved measurement along seven lines across the weld and at six to seven depths. The mountings of each plate for neutron diffraction measurements were such that the diffraction vector was parallel to each of the three primary orthogonal directions of the plate: two in-plane directions, longitudinal and transverse, and the direction normal to the plate (shown in left figure within Table 1). From the three orthogonal strains for each location, the residual stresses along the three plate directions were calculated. The principal axes of the strain and stress tensors, however, need not necessarily align with the plate coordinate system. To explore this, plate P-5 was selected for examination of the possibility that the principal axes of strain are not along the sample coordinate system axes. If adequate data could be collected the goal would be to determine the strain tensor's orientation and magnitude of strain along each principle axis direction.

  1. Advanced Integration in Multi-Scale Mechanics and Welding Process Simulation in Weld Integrity Assessment

    SciTech Connect (OSTI)

    Vitek, J.M.; Wilkowski, G.M.; Brust, F.W.; Babu, S.

    2008-01-30T23:59:59.000Z

    In this project, mathematical models that predict the microstructure in pipeline steel welds were to be developed. These models were to be integrated with thermal models that describe the time-temperature history in the weld as a function of location in order to derive the spatial variation of microstructure in the weld. The microstructure predictions were also to be combined with microstructure-hardness relations, based on the additivity principle, to determine the spatial variation of hardness in the weld. EMC2 also developed microstructural models based on empirical relationships. ORNL was to pursue the development of more fundamental, theoretically based models. ORNL applied a previously developed model for inclusion formation to predict the extent and nature of inclusions that form during weld cooling from the liquid. This inclusion model was directly integrated with computational thermodynamics capability. A convenient user interface was developed for both the inclusion model and the thermodynamic phase-stability calculations. The microstructure model was based on the simultaneous transformation theory analysis as applied to the transformation of austenite to various ferrite constituents during weld cooling. The model available on the Materials Algorithm Project web site was used. Extensive modification of this model was required to correct problems with compilation and calculations as a function of the computational platform (Unix, Linux, Windows, etc.) that was used. The user interface for the inclusion model and thermodynamic phase-stability calculations was delivered to EMC2 along with the modified and correct microstructure model. Evaluation of the theoretically based model will be carried out and the predictions will be compared with experimental results as well as predictions based on the empirical models developed by EMC2.

  2. HAZ hardenability in welded C-Mn steels: The role of prior microstructure

    SciTech Connect (OSTI)

    Sarafinchin, D.; Patchett, B.M.

    1994-12-31T23:59:59.000Z

    The hardenability of the heat-affected zone (HAZ) in C-Mn steels is one of the primary influences on susceptibility to HAC in welded structures. Procedure control of HAZ hardness is based on the use of preheat and/or heat input to limit the peak HAZ hardness to 350--450 Hv10, depending on hydrogen level. Determination of procedural conditions depends on material thickness and carbon equivalent, but does not involve prior microstructure. This study investigated the influence of hot-rolled and normalized base metal microstructures on the level, development and location of peak hardness in steels of identical chemical composition. One heat of A516Gr70 steel in the hot-rolled condition was cut in two and one-half was normalized. This produced microstructures of differing grain size and pearlite coarseness. Gas tungsten arc welding (GTAW) fusion welds at two heat inputs (0.5 and 2.5 KJ/mm) were placed in each of the two base metals. Macro-and microhardness surveys and metallographic analysis were used o determine the location and level of HAZ hardness. Carbon gradients due to incomplete dissolution of cementite and lack of time for homogenization by diffusion cause significant differences in macro-and microhardness of HAZ constituents in A516Gr70 weld zones. Increased pearlite grain size, and to a lesser extent, pearlite lamellar thickness, produce martensitic zones of high hardness in hot-rolled A516Gr70 in two regions: at temperatures just over the A{sub 3} and at temperatures just over the A{sub 1}. Of the two, the region just over the A{sub 3} although removed from the fusion line, has the highest HAZ hardness and is most likely to be susceptible to HAC. Normalized steel is likely to be more resistant to HAC in the HAZ than hot-rolled steel of identical chemical composition.

  3. Fusion-bonded epoxy coating defects on weld center line of submerged-arc welded pipe

    SciTech Connect (OSTI)

    Sokol, D.R.; Herndon, C.M. (Tenneco Oil Co., Houston, TX (USA))

    1990-08-01T23:59:59.000Z

    The problem of weld center line coating defects in fusion-bonded epoxy coatings has occurred on pipe produced in Europe, North America, and Asia. At various times, the defects have been attributed to coating application practices, powder manufacturing, pipe manufacturing, welding methods, and overly critical inspectors. This article details plant experience and experimental trails that led to the identification of the cause and proof of the solution. The ultimate effect of initial coating defects on cathodic protection requirements is a matter of concern also.

  4. On Optimal Reconstruction of Constitutive Vladislav Bukshtynov a

    E-Print Network [OSTI]

    Protas, Bartosz

    of this approach is illustrated by the reconstruction of the temperature dependence of the thermal conductivity difficult by the fact that these coefficients tend to depend on the temperature in a com- plicated way comes from our research on optimization of multiphysics phenomena involved in advanced welding processes

  5. Probabilistic Planning for Predictive Condition Monitoring and Adaptation Probabilistic Planning for Predictive Condition Monitoring and

    E-Print Network [OSTI]

    Paderborn, Universitt

    Planning for Predictive Condition Monitoring and Adaptation Within the Self-Optimizing Energy Management: self-optimizing systems, dependability, prob- abilistic planning, energy management 1. SelfProbabilistic Planning for Predictive Condition Monitoring and Adaptation Paper: Probabilistic

  6. SF 2001-WLD;CONTRACTOR WELDING, CUTTING AND BRAZING

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    01-WLD (11-2012) Supersedes (4-2010) Issue CONTRACTOR WELDING, CUTTING, BRAZING P ART 1: CO NT R ACT O R' S E X PO S UR E AS S E S SM ENT Identify what welding, cutting andor...

  7. arc welding automation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    arc welding automation First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Double-Sided Arc Welding...

  8. FUNDAMENTAL ASPECTS OF ELECTROSLAG WELDING OF TITANIUM ALLOYS

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) . l J FUNDAMENTAL ASPECTS OF ELECTROSLAG WELDING OF TITANIUM ALLOYS J. H. Devletian, S. J. Chen and electrical prop- erties of titanium, commercial welding processes used to join thick section titanium alloys techno1ogy for ESW of titanium alloys was that reported by Gurevich and others in the Soviet technical

  9. Dual Sync Pulse orbital welding of Zeron 100

    SciTech Connect (OSTI)

    Warburton, G.R.; Spence, M.A. [Weir Materials Ltd., Manchester (United Kingdom); Potter, S.R. [Dimetrics, Inc., Davidson, NC (United States)

    1994-12-31T23:59:59.000Z

    The paper describes a new orbital GTAW welding system. Dual Synchronized Pulsation is a further development of the Sync Pulse mode of operation. In Sync Pulse operation the primary weld parameters (current, voltage and wire feed speed) are pulsed between a primary and background value together with synchronization to the torch oscillation position allied with presetting duration using in dwell, excursion and out dwell times. Dual Sync Pulse utilizes two wire feed systems feeding a chill wire directly into the rear of the weld pool on the side opposite the weld torch and the main wire feed. The chill wires fed into the trailing side of the torch absorbs energy from the weld pool effectively limiting heat transmitted to the base material. This technique provides higher deposition rates, decreased welding times and lower heat inputs per pound of deposited metal. Using Dual Sync Pulse, substantial increases in metal deposition rate compared to single wire technique were obtained together with lower heat inputs per kg (pound) of deposited metal. Both mechanical properties and corrosion test results met normal fabrication specification requirements. No evidence of intermetallic phase precipitation was found using optical microscopy. The ability to increase deposition rate without concurrent increase in heat input offers the fabricator significant advantages when welding a super duplex stainless steels such as Zeron 100. In addition, the reduced number of runs and lower heat inputs provide welds with less hoop shrinkage and lower residual stress.

  10. Pressure Resistance Welding of High Temperature Metallic Materials

    SciTech Connect (OSTI)

    Larry Zirker; Craig Tyler

    2010-08-01T23:59:59.000Z

    Engineers from the Idaho National Laboratory (INL) have demonstrated an innovative method for seal or pinch welding stainless steel tubing. Sometimes a tube has fuel or contamination that must be contained, or the tube needs to be shortened or cut for handling, and the tube needs to have a guaranteed sealed weld that is both quick and easy. This technique was demonstrated in a laboratory using a resistance welding system with specially designed electrodes to ensure a tube end is seal welded or if a long tube is to be shortened, the severed ends are seal welded. The unique electrodes design is integral to achieving the sealed ends. This process could readily be adapted for robotic--remote handling or for contact handling in a glovebox or hood.

  11. Method for laser welding a fin and a tube

    DOE Patents [OSTI]

    Fuerschbach, Phillip W. (Tijeras, NM); Mahoney, A. Roderick (Albuquerque, NM); Milewski, John O (Santa Fe, NM)

    2001-01-01T23:59:59.000Z

    A method of laser welding a planar metal surface to a cylindrical metal surface is provided, first placing a planar metal surface into approximate contact with a cylindrical metal surface to form a juncture area to be welded, the planar metal surface and cylindrical metal surface thereby forming an acute angle of contact. A laser beam, produced, for example, by a Nd:YAG pulsed laser, is focused through the acute angle of contact at the juncture area to be welded, with the laser beam heating the juncture area to a welding temperature to cause welding to occur between the planar metal surface and the cylindrical metal surface. Both the planar metal surface and cylindrical metal surface are made from a reflective metal, including copper, copper alloys, stainless steel alloys, aluminum, and aluminum alloys.

  12. Weld Tests Conducted by the Idaho National Laboratory

    SciTech Connect (OSTI)

    Larry Zirker; Lance Lauerhass; James Dowalo

    2007-02-01T23:59:59.000Z

    During the fiscal year of 2006, the Idaho National Laboratory (INL) performed many tests and work relating to the Mobile Melt-Dilute (MMD) Project components. Tests performed on the Staubli quick disconnect fittings showed promising results, but more tests were needed validate the fittings. Changes were made to the shield plug designreduced the closure groove weld depth between the top of the canister and the top plate of the shielding plug from 0.5-in to 0.375-in deep. Other changes include a cap to cover the fitting, lifting pintle and welding code citations on the prints. Tests conducted showed stainless steel tubing, with 0.25-in, 0.375-in, and 0.5-in diameters, all with 0.035-in wall thickness, could be pinch seal welded using commercially available resistance welding equipment. Subsequent testing showed that these welds could be real-time inspected with ultrasonic inspection methods.

  13. Heat and mass transfer in the gas tungsten and gas metal arc welding processes

    SciTech Connect (OSTI)

    Watkins, A.D; Smartt, H.B.; Einerson, C.J.; Watkins, J.A.

    1990-01-01T23:59:59.000Z

    The heat transferred from an electrode negative, argon gas tungsten arc to an anode was measured for a wide range of conditions suitable for mechanized welding. The results are given as (1) the arc efficiency and (2) the anode heat and current input distributions for various anode materials over a range of current and voltage. The nominal arc is Gaussian, {approximately}4 mm in diameter, with {approximately}75{percent}heat transfer efficiency. Variations from these values are discussed in terms of the electrical and thermal energy transport mechanisms. Heat transferred to the workpiece (cathode) during direct current, electrode positive gas metal arc welding (GMAW) was measured for various parameters applicable to machine welding. The results are presented as a function of electrode speed for changing voltages and contact tip to workpiece distances. The total heat transfer efficiency was nominally 85{percent} for a 0.89 mm diameter steel electrode using an argon-2{percent} oxygen shielding gas; the nominal heat transfer efficiency of the droplet component was 40{percent}. The average droplet temperatures ranged from 2400 to 3100 K, depending on the process parameters. A new method of measuring the heat transferred from the arc to the workpiece, using a boiling liquid nitrogen calorimeter, has been developed that gives rapid, accurate values. 20 refs., 8 figs., 2 tabs.

  14. The dynamics of droplet formation and detachment in gas metal arc welding

    SciTech Connect (OSTI)

    Johnson, J.A.; Smartt, H.B.; Clark, D.E.; Carlson, N.M.; Watkins, A.D.; Lethcoe, B.J.

    1990-01-01T23:59:59.000Z

    Experimental measurements of gas metal arc welding are required for the development and confirmation of models of the process. This paper reports on two experiments that provide information for models of the arc physics and of the weld pool dynamics. The heat transfer efficiency of the spray transfer mode in gas metal arc welding was measured using a calorimetry technique. The efficiency varied from 75 to 85%. A special fixture was used to measure the droplet contribution, which is determined to be between 35 and 45% of the total input energy. A series of experiments was performed at a variety of conditions ranging from globular to spray to streaming transfer. The transfer was observed by taking high-speed movies at 500 to 5000 frames per second of the backlighted droplets. An automatic image analysis system was used to obtain information about the droplets including time between detachments, droplet size, and droplet acceleration. At the boundary between the globular and spray modes, the droplet size varies between small droplets that melt off faster than average, resulting in a smaller electrode extension, and large droplets that melt off slower than average, resulting in an increase in the electrode extension. 5 refs., 4 figs., 2 tabs.

  15. Two-Level Weld-Material Homogenization for Efficient Computational Analysis

    E-Print Network [OSTI]

    Grujicic, Mica

    , 2011) The introduction of newer joining technologies like the so-called friction-stir welding (FSW, friction-stir welding, material-model development 1. Introduction During the current decade, the U-called Friction Stir Welding (FSW) solid-state process. FSW was invented and patented by The Welding Institute (UK

  16. Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine

    E-Print Network [OSTI]

    Carmignani, B

    2005-01-01T23:59:59.000Z

    Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine

  17. UNIVERSITY OF WASHINGTON [DEPARTMENT NAME] HOT WORK PERMIT (For use outside of welding booths)

    E-Print Network [OSTI]

    Wilcock, William

    UNIVERSITY OF WASHINGTON [DEPARTMENT NAME] HOT WORK PERMIT (For use outside of welding boothsW 1032 (6/2013) WELDING/CUTTING/OPEN FLAME All welding/cutting/open flame equipment is in good repair and welding, (10 feet for other open flame operations). Combustible walls are protected. Combustible floors

  18. A Level Set Approach for the Simulation of the Multipass Hybrid Laser / GMA Welding Process

    E-Print Network [OSTI]

    1 A Level Set Approach for the Simulation of the Multipass Hybrid Laser / GMA Welding Process model, developed in a level set approach, is proposed to model hybrid gas metal arc / laser welding equation, the momentum and mass conservation equations and the weld bead development. The arc welding total

  19. The application of nanosecond-pulsed laser welding technology in MEMS packaging with a shadow mask$

    E-Print Network [OSTI]

    Lin, Liwei

    The application of nanosecond-pulsed laser welding technology in MEMS packaging with a shadow mask wiring is not pre- ferred. A comprehensive review on laser welding was given in [6]. The laser welding of laser welding is to create the liquid pool by absorption of incident radiation, allow it to grow

  20. LASER WELDING -Literature Review Materials Science and Metallurgy Department, University of Cambridge, England. July 2002.

    E-Print Network [OSTI]

    Cambridge, University of

    LASER WELDING - Literature Review C.A. Walsh Materials Science and Metallurgy Department industry to produce seam or stitch welds, as alternatives to conventional resistance spot welding, which are used extensively for attaching auto-body panels to sub- assemblies. The advantages of laser welding

  1. ~.,Slag-Metal Equilibrium During Submerged e-~~ Arc Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ~~ . ~.,Slag-Metal Equilibrium During Submerged e-~~ Arc Welding C. S. CHAI AND T. W. EAGAR A thermodynamic model of the equilibria existing between the slag and the weld metal during submerged arc welding over forty years ago, submerged arc welding has developed into one of the most efficient, most reliable

  2. Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    - 1 - Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding Olivier dimensional finite element model has been developed to simulate weld bead formation in multi pass hybrid laser/gas metal arc welding. The model considers both a gas metal arc welding (GMAW) electrode and a laser beam

  3. Matrix penetration in the bulk:In uence of humidity: Morphological analysis of wood welding

    E-Print Network [OSTI]

    Dalang, Robert C.

    Matrix penetration in the bulk:In uence of humidity: Morphological analysis of wood welding.pichelin@b .ch Context: Wood can be welded using linear vibration welding tech- niques similar to the ones in plastic and metal industry[1] . Wood welding allows bonding strength similar to glued joints. However, due

  4. Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding, material microstructure and properties in friction stir welding welds of AA5083 (a non welding, Johnson-Cook material model 1. Introduction In this study, an attempt is made to modify

  5. ORIGINAL ARTICLE Development of a mobile welding robot for double-hull structures

    E-Print Network [OSTI]

    Kim, Jongwon

    ORIGINAL ARTICLE Development of a mobile welding robot for double-hull structures in shipbuilding describes the development of a self- driving mobile welding robot. The robot is used to weld U-shaped welding areas in enclosed double-hull structures. In order to place itself inside the double

  6. SHRINK-FITTING AND DOWEL WELDING IN MORTISE AND TENON STRUCTURAL WOOD JOINTS

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    SHRINK-FITTING AND DOWEL WELDING IN MORTISE AND TENON STRUCTURAL WOOD JOINTS E.Mougel1 , C.Segovia1 welded dowels. Increasing the number of welded dowels, however, produced joints of higher strength than those bonded just by shrink-fitting. Combining in the same joint both dowel welding and shrink

  7. welding And MAteriAlS College of Rural and Community Development

    E-Print Network [OSTI]

    Hartman, Chris

    welding And MAteriAlS technology College of Rural and Community Development Community and Technical College 907-455-2932 www.ctc.uaf.edu/programs/weld/ Welding is an important industrial skill from welding basics to advanced pipe and metal plate fabrication. Classes are small to offer hands

  8. THE PHYSICS OF ARC WELDING PROCESSES Department of Materials Science and Engineering,

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) THE PHYSICS OF ARC WELDING PROCESSES T.W.EAGAR Department of Materials Science and Engineering, Massachusetts Institute of Technology Abstract Welding is an extremely complex proce ss; however, due to its Wor ds: Arc Welding, Arc Physics, Shielding Gases, Gas Metal Arc Welding. 1. Introduction Langmuir

  9. ~ WELDING RESEARCH ~Jlj~~~-------------!ID~ SUPPLEMENT TO THE tVELOING JOURNAL. IULY 1993

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ~ WELDING RESEARCH ~Jlj~~~-------------!ID~ SUPPLEMENT TO THE tVELOING JOURNAL. IULY 1993 Sponsored by the American Welding Society and the Welding Research Council Metal Transfer in Pulsed Current Gas Metal Arc Welding A static force balance analysis was used to estimate the melting rates

  10. TRANSMISSION WELDING OF GLASSES BY FEMTOSECOND LASER: STRUCTURAL AND MECHANICAL PROPERTIES

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    TRANSMISSION WELDING OF GLASSES BY FEMTOSECOND LASER: STRUCTURAL AND MECHANICAL PROPERTIES Paper M processing parameters enables transmission welding. The morphology of the weld cross section was studied of the weld seams were studied through spatially resolved nanoindentation, and indentation fracture analysis

  11. F i W ldi PFusion Welding -Processes ME 6222: Manufacturing Processes and Systems

    E-Print Network [OSTI]

    Colton, Jonathan S.

    F i W ldi PFusion Welding - Processes ver. 1 ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2009 1 #12;Fusion weldingFusion welding Intimate interfacial contact by using a liquid of substantiallyg q y similar composition to the base materials. Heat + filler material = weld Heat + filler

  12. RESONANT TRANSITION SWITCHING WELDING POWER SUPPLY N. Frohleke, H. Mundinger, S. Beineke, P. Wallmeier, H. Grotstollen

    E-Print Network [OSTI]

    Paderborn, Universitt

    RESONANT TRANSITION SWITCHING WELDING POWER SUPPLY N. Frohleke, H. Mundinger, S. Beineke, P-bridge topology used in a welding power supply. A new driving scheme adapts the resulting power circuitry for both the droplet and the short-circuiting transfer welding modes occurring in the gas metal arc welding process

  13. F i W ldiFusion Welding ME 4210: Manufacturing Processes and Engineering

    E-Print Network [OSTI]

    Colton, Jonathan S.

    F i W ldiFusion Welding ver. 1 ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton GIT 2009 1 #12;Fusion weldingFusion welding Intimate interfacial contact by using a liquid of substantiallyg q y similar composition to the base materials. Heat + filler material = weld Heat + filler

  14. Slag-Metal Reactions during Welding: Part Ill. Verification of the Theory

    E-Print Network [OSTI]

    Eagar, Thomas W.

    , Slag-Metal Reactions during Welding: Part Ill. Verification of the Theory U. MITRA and T.W. EAGAR. The transfer of carbon and oxygen is also discussed. It is shown that the transfer of oxygen into the weld of inclusions in the solidifying weld pool. Methods of applying this analysis to multipass welds and active

  15. Acta Materialia 59 (2011) 2020-2028 Back of the envelope calculations in friction stir welding

    E-Print Network [OSTI]

    Cambridge, University of

    2011-01-01T23:59:59.000Z

    : friction stir welding; modeling; theory; velocity field; peak temperature; torque; hardness; aluminum welding (FSW), well-tested analytical models of materials flow, peak temperatures, torque, and weldActa Materialia 59 (2011) 2020-2028 1 Back of the envelope calculations in friction stir welding

  16. Materials and Design 50 (2013) 38-43 Regeneration Technique for Welding Nanostructured Bainite

    E-Print Network [OSTI]

    Cambridge, University of

    2013-01-01T23:59:59.000Z

    by spark wire cutting. Bead-on-plate welds with autogenous gas tungsten arc welding were perform by the heat input during welding, from transforming into brittle martensite. The microstructures of the fusion to the formation of brittle, untempered martensite. Hong et al. [6] attempted a rapid post-weld heat treatment

  17. Optimization Online

    E-Print Network [OSTI]

    Optimization Online is a repository of e-prints about optimization and related topics. Submissions to Optimization Online are moderated by a team of volunteer

  18. Quiz # 7, STAT 383, Prof. Suman Sanyal, April 8, 2009 (Q2, Page 354) To decide whether the pipe welds in a nuclear power plant meet

    E-Print Network [OSTI]

    Sanyal, Suman

    welds in a nuclear power plant meet specifications, a random sample of welds is to be selected : nuclear power plants is to determine if welds

  19. Influence of Aluminum Content on Grain Refinement and Strength of AZ31 Magnesium GTA Weld Metal

    SciTech Connect (OSTI)

    Babu, N. Kishore [Singapore Institute of Manufacturing Technology; Cross, Carl E. [Los Alamos National Laboratory

    2012-06-28T23:59:59.000Z

    The goal is to characterize the effect of Al content on AZ31 weld metal, the grain size and strength, and examine role of Al on grain refinement. The approach is to systematically vary the aluminum content of AZ31 weld metal, Measure average grain size in weld metal, and Measure cross-weld tensile properties and hardness. Conclusions are that: (1) increased Al content in AZ31 weld metal results in grain refinement Reason: higher undercooling during solidification; (2) weld metal grain refinement resulted in increased strength & hardness Reason: grain boundary strengthening; and (3) weld metal strength can be raised to wrought base metal levels.

  20. Historical overview on Vacuum suitable Welding and fatigue resistance in Research Devices

    E-Print Network [OSTI]

    Wolf, Martin

    2015-01-01T23:59:59.000Z

    New inventions change the approach of vacuum suitable welding for research purpose. With orbital welding, laser welding and robot welding the possibilities increase to fabricate larger vessels more accurately. Despite this development there is still no perfect understanding on how to avoid virtual leaks and how to make such joints suitable for dynamic stress. By recalling its historical development, it is apparent how welding mistakes began occurring systematically and how to avoid them. With ASDEX-Upgrade as an example, it is shown how the attempt to conduct vacuum suitable welding has decreased the fatigue strength. ITER could repeat the mistakes of ASDEX-Upgrade even for unwanted welding (accidental fusing of joints).

  1. Microstructure characterization of laser welded Ti-6Al-4V fusion zones

    SciTech Connect (OSTI)

    Xu, Pei-quan; Li, Leijun, E-mail: leijun.li@ualberta.ca; Zhang, Chunbo

    2014-01-15T23:59:59.000Z

    The as-welded microstructure of laser-welded Ti-6Al-4V is characterized as a function of CO2 key-hole mode laser welding speed. Martensitic ?? is the predominant phase, with some ? and retained ?. Phase transformation is affected by the cooling rate through laser welding speed. A higher welding speed of 1.6 to 2.0 m/min produced more martensite ?? and less retained ? in the welds. 1.4 m/min welding speed produced small amounts of ?, besides the martensite ??. A trace of ? titanium hydride phase seems to have formed in the weld fusion zone. Moir fringes are a common feature in the TEM microstructure, due to abundance of multi-phase interfaces. Tensile twins and clusters of dislocations indicate that plastic deformation has happened in the as-welded microstructure, indicating the local stress levels to be approaching the yield stress on-cooling during laser welding.

  2. Optimal Real-time Dispatch for Integrated Energy Systems

    E-Print Network [OSTI]

    Firestone, Ryan Michael

    2007-01-01T23:59:59.000Z

    Hybrid Optimization Model for Electric Renewables heating, ventilation, and air conditioning integrated energy system

  3. Matching univalent functions and conformal welding

    E-Print Network [OSTI]

    Grong, Erlend; Vasil'ev, Alexander

    2008-01-01T23:59:59.000Z

    Given a conformal mapping $f$ of the unit disk $\\mathbb D$ onto a simply connected domain $D$ in the complex plane bounded by a closed Jordan curve, we consider the problem of constructing a matching conformal mapping, i.e., the mapping of the exterior of the unit disk $\\mathbb D^*$ onto the exterior domain $D^*$ regarding to $D$. The answer is expressed in terms of a linear differential equation with a driving term given as the kernel of an operator dependent on the original mapping $f$. Examples are provided. This study is related to the problem of conformal welding and to representation of the Virasoro algebra in the space of univalent functions.

  4. Matching univalent functions and conformal welding

    E-Print Network [OSTI]

    Erlend Grong; Pavel Gumenyuk; Alexander Vasil'ev

    2008-06-05T23:59:59.000Z

    Given a conformal mapping $f$ of the unit disk $\\mathbb D$ onto a simply connected domain $D$ in the complex plane bounded by a closed Jordan curve, we consider the problem of constructing a matching conformal mapping, i.e., the mapping of the exterior of the unit disk $\\mathbb D^*$ onto the exterior domain $D^*$ regarding to $D$. The answer is expressed in terms of a linear differential equation with a driving term given as the kernel of an operator dependent on the original mapping $f$. Examples are provided. This study is related to the problem of conformal welding and to representation of the Virasoro algebra in the space of univalent functions.

  5. Lienert named American Welding Society Fellow

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5Let us count theLienert named American Welding

  6. Friction stir welding and processing of oxide dispersion strengthened (ODS) alloys

    DOE Patents [OSTI]

    Ren, Weiju

    2014-11-11T23:59:59.000Z

    A method of welding including forming a filler material of a first oxide dispersoid metal, the first oxide dispersoid material having first strengthening particles that compensate for decreases in weld strength of friction stir welded oxide dispersoid metals; positioning the filler material between a first metal structure and a second metal structure each being comprised of at least a second oxide dispersoid metal; and friction welding the filler material, the first metal structure and the second metal structure to provide a weld.

  7. A study of the mechanism of laser welding defects in low thermal expansion superalloy GH909

    SciTech Connect (OSTI)

    Yan, Fei; Wang, Chunming, E-mail: yanxiangfei225@163.com; Wang, Yajun; Hu, Xiyuan; Wang, Tianjiao; Li, Jianmin; Li, Guozhu

    2013-04-15T23:59:59.000Z

    In this paper, we describe experimental laser welding of low-thermal-expansion superalloy GH909. The main welding defects of GH909 by laser in the weld are liquation cracks and porosities, including hydrogen and carbon monoxide porosity. The forming mechanism of laser welding defects was investigated. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum, X-ray diffractometer and other methodologies. The results demonstrated that porosities appearing in the central weld were related to incomplete removal of oxide film on the surface of the welding samples. The porosities produced by these bubbles were formed as a result of residual hydrogen or oxygenium in the weld. These elements failed to escape from the weld since laser welding has both a rapid welding speed and cooling rate. The emerging crack in the heat affected zone is a liquation crack and extends along the grain boundary as a result of composition segregation. LavesNi{sub 2}Ti phase with low melting point is a harmful phase, and the stress causes grain boundaries to liquefy, migrate and even crack. Removing the oxides on the surface of the samples before welding and carefully controlling technological parameters can reduce welding defects and improve formation of the GH909 alloy weld. - Highlights: ? It is a new process for the forming of GH909 alloy via laser welding. ? The forming mechanism of laser welding defects in GH909 has been studied. ? It may be a means to improve the efficiency of aircraft engine production.

  8. Friction Stir Spot Welding of DP780 Carbon Steel

    SciTech Connect (OSTI)

    Santella, Michael L [ORNL; Hovanski, Yuri [ORNL; Frederick, David Alan [ORNL; Grant, Glenn J [ORNL; Dahl, Michael E [ORNL

    2010-01-01T23:59:59.000Z

    Friction stir spot welds were made in uncoated and galvannealed DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1 to 10 s. Increasing tool rotation speed from 800 to 1600 rev min{sup -1} increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap shear strengths exceeding 10 {center_dot} 3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

  9. Hot Pin Welding of Thin Poly(vinyl chloride) Sheet James D. Van de Ven, Arthur G. Erdman

    E-Print Network [OSTI]

    Van de Ven, James D.

    Hot Pin Welding of Thin Poly(vinyl chloride) Sheet James D. Van de Ven, Arthur G. Erdman Mechanical of welding two thin sheets of poly(vinyl chloride) (PVC) with a heated pin, thus allowing construction of a relationship between the weld temperature and weld strength. Constructing a relationship between weld strength

  10. Investigation of Iron Aluminide Weld Overlays

    SciTech Connect (OSTI)

    Banovic, S.W.; DuPont, J.B.; Levin, B.F.; Marder, A.R.

    1999-08-02T23:59:59.000Z

    Conventional fossil fired boilers have been retrofitted with low NO(sub)x burners in order for the power plants to comply with new clean air regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion typically has been enhanced resulting in premature tube failure. To protect the existing panels from accelerated attack, weld overlay coatings are typically being applied. By depositing an alloy that offers better corrosion resistance than the underlying tube material, the wastage rates can be reduced. While Ni-based and stainless steel compositions are presently providing protection, they are expensive and susceptible to failure via corrosion-fatigue due to microsegregation upon solidification. Another material system presently under consideration for use as a coating in the oxidation/sulfidation environments is iron-aluminum. These alloys are relatively inexpensive, exhibit little microsegregation, and show excellent corrosion resistance. However, their use is limited due to weldability issues and their lack of corrosion characterization in simulated low NO(sub)x gas compositions. Therefore a program was initiated in 1996 to evaluate the use of iron-aluminum weld overlay coatings for erosion/corrosion protection of boiler tubes in fossil fired boilers with low NO(sub)x burners. Investigated properties included weldability, corrosion behavior, erosion resistance, and erosion-corrosion performance.

  11. Method for laser welding ultra-thin metal foils

    DOE Patents [OSTI]

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-26T23:59:59.000Z

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld. 5 figs.

  12. Welding fixture for nuclear fuel pin cladding assemblies

    DOE Patents [OSTI]

    Oakley, David J. (Richland, WA); Feld, Sam H. (West Richland, WA)

    1986-01-01T23:59:59.000Z

    A welding fixture for locating a driver sleeve about the open end of a nuclear fuel pin cladding. The welding fixture includes a holder provided with an open cavity having shoulders for properly positioning the driver sleeve, the end cap, and a soft, high temperature resistant plastic protective sleeve that surrounds a portion of the end cap stem. Ejected contaminant particles spewed forth by closure of the cladding by pulsed magnetic welding techniques are captured within a contamination trap formed in the holder for ultimate removal and disposal of contaminating particles along with the holder.

  13. Method for laser welding ultra-thin metal foils

    DOE Patents [OSTI]

    Pernicka, John C. (Fort Collins, CO); Benson, David K. (Golden, CO); Tracy, C. Edwin (Golden, CO)

    1996-01-01T23:59:59.000Z

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld.

  14. Welding fixture for nuclear fuel pin cladding assemblies

    DOE Patents [OSTI]

    Oakley, D.J.; Feld, S.H.

    1984-02-22T23:59:59.000Z

    A welding fixture is described for locating a driver sleeve about the open end of a nuclear fuel pin cladding. The welding fixture includes a holder provided with an open cavity having shoulders for properly positioning the driver sleeve, the end cap, and a soft, high temperature resistant plastic protective sleeve that surrounds a portion of the end cap stem. Ejected contaminant particles spewed forth by closure of the cladding by pulsed magnetic welding techniques are captured within a contamination trap formed in the holder for ultimate removal and disposal of contaminating particles along with the holder.

  15. Inspection apparatus for evaluating a partially completed weld

    DOE Patents [OSTI]

    Smartt, Herschel B. (Idaho Falls, ID); Larsen, Eric D. (Idaho Falls, ID); Johnson, Jonn A. (Idaho Falls, ID)

    2001-01-01T23:59:59.000Z

    An inspection apparatus for evaluating a partially completed weld is described and which is utilized in combination with an automated movable welder which moves across a supporting surface, and wherein the inspection apparatus includes a coupling member mounted on the welder; a frame member mounted on the coupling member; an ultrasonic sensor mounted on the frame member and disposed in ultrasonic sound transmitting relation relative to the partially completed weld; and a drive assembly for adjusting the position of the ultrasonic sensor relative to the partially completed weld.

  16. Welding Metallurgy and Processing Issues for Joining of Power Sources

    SciTech Connect (OSTI)

    Lienert, Thomas J. [Los Alamos National Laboratory; Reardon, Patrick T. [Los Alamos National Laboratory

    2012-08-14T23:59:59.000Z

    Weldability issues with the pertinent alloys have been reviewed and preliminary results of our work on Haynes 25 have been presented. Further results on the mechanical properties and metallography on the EB welds are imminent. Hot-ductility experiments will commence within a few weeks. Aging studies on the effects of heat treatment using the Gleeble are also planned. MST-6 has extensive background in the welding metallurgy of the pertinent alloys. We also have considerable experience with the various welding processes to be used.

  17. Addressing employee concerns about welding in a nuclear power plant

    SciTech Connect (OSTI)

    Danko, J.C.; Hansen, D.D.; O'Leary, P.D.

    1988-03-01T23:59:59.000Z

    A leading utility contracted with EG and G Idaho to perform a comprehensive, independent evaluation of the utility's welding program with respect to the safety-related welds made at one of its nuclear power plants. The purpose of this paper is to review a number of the employee concerns and the technical basis for the disposition of these concerns. In addition, recommendations are presented that may help to prevent the recurrence of employee concerns in future nuclear power plant construction, and thereby costly delays may be avoided and welding productivity and quality improved.

  18. Optimization Journals, Sites, Societies

    E-Print Network [OSTI]

    Optimization Online Links. Optimization related societies. Mathematical Optimization Society SIAM INFORMS. Optimization related journals. Mathematical...

  19. Review of Dissimilar Metal Welding for the NGNP Helical-Coil Steam Generator

    SciTech Connect (OSTI)

    John N. DuPont

    2010-03-01T23:59:59.000Z

    The U.S. Department of Energy (DOE) is currently funding research and development of a new high temperature gas cooled reactor (HTGR) that is capable of providing high temperature process heat for industry. The steam generator of the HTGR will consist of an evaporator economizer section in the lower portion and a finishing superheater section in the upper portion. Alloy 800H is expected to be used for the superheater section, and 2.25Cr 1Mo steel is expected to be used for the evaporator economizer section. Dissimilar metal welds (DMW) will be needed to join these two materials. It is well known that failure of DMWs can occur well below the expected creep life of either base metal and well below the design life of the plant. The failure time depends on a wide range of factors related to service conditions, welding parameters, and alloys involved in the DMW. The overall objective of this report is to review factors associated with premature failure of DMWs operating at elevated temperatures and identify methods for extending the life of the 2.25Cr 1Mo steel to alloy 800H welds required in the new HTGR. Information is provided on a variety of topics pertinent to DMW failures, including microstructural evolution, failure mechanisms, creep rupture properties, aging behavior, remaining life estimation techniques, effect of environment on creep rupture properties, best practices, and research in progress to improve DMW performance. The microstructure of DMWs in the as welded condition consists of a sharp chemical concentration gradient across the fusion line that separates the ferritic and austenitic alloys. Upon cooling from the weld thermal cycle, a band of martensite forms within this concentration gradient due to high hardenability and the relatively rapid cooling rates associated with welding. Upon aging, during post weld heat treatment (PWHT), and/or during high temperature service, C diffuses down the chemical potential gradient from the ferritic 2.25Cr 1Mo steel toward the austenitic alloy. This can lead to formation of a soft C denuded zone near the interface on the ferritic steel, and nucleation and growth of carbides on the austenitic side that are associated with very high hardness. These large differences in microstructure and hardness occur over very short distances across the fusion line (~ 50 100 ?m). A band of carbides also forms along the fusion line in the ferritic side of the joint. The difference in hardness across the fusion line increases with increasing aging time due to nucleation and growth of the interfacial carbides. Premature failure of DMWs is generally attributed to several primary factors, including: the sharp change in microstructure and mechanical properties across the fusion line, the large difference in coefficient of thermal expansion (CTE) between the ferritic and austenitic alloys, formation of interfacial carbides that lead to creep cavity formation, and preferential oxidation of the ferritic steel near the fusion line. In general, the large gradient in mechanical properties and CTE serve to significantly concentrate the stress along the fusion where a creep susceptible microstructure has evolved during aging. Presence of an oxide notch can concentrate the stress even further. Details of the failure mechanism and the relative importance of each factor varies.

  20. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    SciTech Connect (OSTI)

    Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The department for Applied Physics, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg; Koleva, E. G., E-mail: eligeorg@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784, Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora,1309, Sofia (Bulgaria); Belenkiy, V. Ya., E-mail: mtf@pstu.ru; Varushkin, S. V., E-mail: stepan.varushkin@mail.ru [The department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

    2014-04-15T23:59:59.000Z

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup ?3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 Am{sup ?2}, i.e. 8 mA for a 310 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  1. Examination of the 1970 National Bureau of Standards Underground Corrosion Test Welded Stainless STeel Coupons from Site D

    SciTech Connect (OSTI)

    L. R. Zirker; M. K. Adler Flitton; T. S. Yoder; T. L. Trowbridge

    2008-01-01T23:59:59.000Z

    A 1970 study initiated by the National Bureau of Standards (NBS), now known as the National Institute of Standards and Technology (NIST), buried over 6000 corrosion coupons or specimens of stainless steel Types 201, 202, 301, 304, 316, 409, 410, 430, and 434. The coupons were configured as sheet metal plates, coated plates, cross-welded plates, U-bend samples, sandwiched materials, and welded tubes. All coupons were of various heat-treatments and cold worked conditions and were buried at six distinctive soil-type sites throughout the United States. The NBS scientists dug five sets of two trenches at each of the six sites. In each pair of trenches, they buried duplicate sets of stainless steel coupons. The NBS study was designed to retrieve coupons after one year, two years, four years, eight years, and x years in the soil. During the first eight years of the study, four of five planned removals were completed. After the fourth retrieval, the NBS study was abandoned, and the fifth and final set of specimens remained undisturbed for over 33 years. In 2003, an interdisciplinary research team of industrial, university, and national laboratory investigators were funded under the United States Department of Energys Environmental Management Science Program (EMSP; Project Number 86803) to extract part of the remaining set of coupons at one of the test sites, characterize the stainless steel underground corrosion rates, and examine the fate and transport of metal ions into the soil. Extraction of one trench at one of the test sites occurred in April 2004. This report details only the characterization of corrosion found on the 14 welded couponstwo cross welded plates, six U-bends, and six welded tubesthat were retrieved from Site D, located near Wildwood, NJ. The welded coupons included Type 301, 304, 316, and 409 stainless steels. After 33 years in the soil, corrosion on the coupons varied according to alloy. This report discusses the stress corrosion cracking and crevice corrosion cracking of the U-bend coupons; the minimal corrosion found on the cross-bead plates; and the general, pitting, and crevice corrosion found on the welded tubes. In general, the austenitic Type 301, 304 and 316 samples showed little if any corrosion after 33+-years in the soil, whereas the ferritic alloys-Type 409 and 434 showed a spectrum of corrosion.

  2. Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

    SciTech Connect (OSTI)

    Ribic, B.; DebRoy, T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Burgardt, P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2011-04-15T23:59:59.000Z

    During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

  3. Thermomechanical history measurements on Type 304L stainless steel pipe girth welds

    SciTech Connect (OSTI)

    Li, Ming; Atteridge, D.G.; Anderson, W.E.; Turpin, R. [Oregon Graduate Inst., Portland, OR (United States); West, S.L. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1993-12-31T23:59:59.000Z

    Thermal and strain histories were recorded for three 40-cm-diameter (16 inch), Type 304L stainless steel (SS), schedule 40 (1.27 cm thickness) pipe girth welds. Two weld groove preparations were standard V grooves while the third was a narrow groove configuration. The welding parameters for the three pipe welds simulated expected field practice as closely as possible. The narrow gap weld was completed in four continuous passes while the other two welds required six and nine (discontinuous) passes, due to the use of different weld wire diameters. Thermomechanical history measurements were taken on the inner counterbore surface, encompassing the weld centerline and heat-affected zone (HAZ), as well as 10 cm of inner counterbore surface on either side of the weld centerline; a total of 47 data acquisition instruments were used for each weld. These instruments monitored: (1) weld shrinkages parallel to the pipe axis; (2) surface temperatures; (3) surface strains parallel to weld centerline; and (4) radial deformations. Results show that the weld and HAZ experienced cyclic deformation in the radial direction during welding, indicating that the final residual stress distribution in multi-pass pipe weldments is not axisymmetric. Measured radial and axial deformations were smaller for the narrow gap groove than for the standard V grooves, suggesting that the narrow gap groove weldment may have lower residual stress levels than the standard V groove weldments. This study provides the experimental database and a guideline for further computational modeling work.

  4. arc welding dynamic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Materials Science Websites Summary: diffusivity specific heat thermal conductivity 2 operating parameter (n qv 4a p Tc - T0 net heat i nput- CHANGES OF WELD POOL SHAPE BY...

  5. On-Line Weld NDE with IR Thermography

    Broader source: Energy.gov (indexed) [DOE]

    non-destructive evaluation (NDE) technology for spot weld quality monitoring based on infrared (IR) thermography that can be adopted reliably and cost-effectively in high-volume...

  6. arc welding electrodes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    S 2010-01-01 99 Resistance Spot Welding Characteristic of Ferrite-Martensite DP600 Dual Phase Advanced High Strength Steel-Part III: Mechanical Properties CiteSeer Summary:...

  7. Modeling of the Thermal Field in Dissimilar Alloy Ultrasonic Welding

    E-Print Network [OSTI]

    Jedrasiak, P.; Shercliff, H. R.; Chen, Y. C.; Wang, L.; Prangnell, P.; Robson, J.

    2014-12-10T23:59:59.000Z

    This paper describes a finite element model for predicting the temperature field in high power ultrasonic welding aluminum AA6111 to two dissimilar alloys, magnesium AZ31, and low carbon steel DC04. Experimental thermocouple and other evidence...

  8. Welding Process Decoupling for Improved Control David E. Hardt

    E-Print Network [OSTI]

    Eagar, Thomas W.

    Laboratory for Electromagnetic and Electronic and Systems Massachusetts Institute ofTechnology The Gas Metal, the use of such control methods has not advanced the quality of welding through better process regulation

  9. automated weld characterization: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    relaxation in a welded ASTM 1018 steel plate by using the Thermo-Acousto-Photonic Nondestructive Evaluation (TAP-NDE) technique and (more) Jhun, Choon-Sik 2012-01-01 10...

  10. Welding type 347 stainless steel -- An interpretive report

    SciTech Connect (OSTI)

    Thomas, R.D. Jr.; Messler, R.W. Jr.

    1997-05-01T23:59:59.000Z

    Stainless steels fall into three major classifications: ferritic, austenitic and martensitic. Type 347 stainless steels are classified as austenitic, though, as well be described later, they may contain small amounts of ferrite as well. They are of the 18-8 chromium-nickel type with up to 1% niobium, an element once referred to as columbium. Type 347 stainless steel is the primary focus of this document. Similar stainless steels containing niobium will be included, such as Types 348 and 309Nb, as these are frequently encountered in certain applications in welded construction. Ferritic and duplex stainless steels, some of which may contain niobium, are not within the scope of this report. This report covers the following topics: applicable welding processes; composition; properties; ferrite potential effect of weld thermal cycle; post-weld heat treatments; cracks and microfissures; and industrial applications.

  11. arc welding material: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    remeshing. The heat for the modeling of metal deposition results in a direct calculation of the formation of the weld bead, without any Paris-Sud XI, Universit de 2...

  12. Development of automated welding process for field fabrication of thick walled pressure vessels. (First quarterly report, FY 1981)

    SciTech Connect (OSTI)

    Schneider, U.A.

    1981-01-01T23:59:59.000Z

    The choice of sets of root welding parameters is discussed. Thick field demonstration/qualification welds will be performed. A welding procedure handbook which will be prepared is mentioned. (DLC)

  13. CHARACTERIZATION OF FERRITIC G.M.A. WELD DEPOSITS IN 9percentNi STEEL FOR CRYOGENIC APPLICATIONS

    E-Print Network [OSTI]

    Mahin, Kim Walker

    2013-01-01T23:59:59.000Z

    Soc. , Brit. Weld. Welding Metallurgy, 3rd ed. , pub. Amer.1974. G. Linnert: Welding Metallurgy, 3rd ed. , pub. Amer.and A. Wittmoser: The Metallurgy of Cast Iron, ed. B. Lux,

  14. Residual stress in laser welded dissimilar steel tube-to-tube joints

    SciTech Connect (OSTI)

    Sun, Zheng (Technical Research Centre of Finland, Espoo (Finland). Lab. of Production Engineering)

    1993-09-01T23:59:59.000Z

    Austenitic-ferritic dissimilar steel joints are widely used in power generation systems. Their utilization has proved to be efficient in terms of satisfactory properties and the economics. These types of joints have usually been produced using conventional welding processes, such as tungsten inert gas (TIG) welding. With the rapid development of high power lasers, laser welding has received considerable attention. Laser welding offers many advantages over conventional welding processes, e.g. low heat input, small heat-affected zone (HAZ), small distortion, and welding in an exact and reproducible manner. Residual stress distribution in laser welds may also differ from those made by conventional welding processes due to its special features. Residual stress, particularly tensile residual stress in the weld, can be very important factor in controlling the quality and service life of the welded structure. The formation of tensile residual stress in the weld may result in the initiation of fatigue cracking, stress corrosion cracking or other types of fractures. It is useful, therefore, to understand the distribution of residual stress in austenitic-ferritic laser welds, and thus evaluate the quality of the joints. Although residual stress distribution in the welded joints has been extensively investigated, little data are available for the residual stress distribution in laser welds. The aim of the work was to examine residual stress distribution along laser welds of dissimilar steel tube-to-tube joints, which were made by both autogeneous welding and welding with filler wire. The results were also compared with the joints made by plasma arc and TIG welding.

  15. An investigation of stress concentration effects in welding elbows

    E-Print Network [OSTI]

    Ballard, Mike Wayne

    1987-01-01T23:59:59.000Z

    AN INVESTIGATION OF STRESS CONCENTRATION EFFECTS IN WELDING ELBOWS A Thesis by MIKE WAYNE BALLARD Submitted to the Graduate College of Texas A & M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December, 1986 Major Subject; Mechanical Engineering AN INVESTIGATION OF STRESS CONC~TION EFFECTS IN WELDING ELBOWS A Thesis by MIKE WAYNE BALLARD Approved as to style and content by; Mog Henriksen (Ch ' of Committee) Joh J. (Me er) lorn Brya L...

  16. An investigation of stress concentration effects in welding elbows

    E-Print Network [OSTI]

    Ballard, Mike Wayne

    1987-01-01T23:59:59.000Z

    AN INVESTIGATION OF STRESS CONCENTRATION EFFECTS IN WELDING ELBOWS A Thesis by MIKE WAYNE BALLARD Submitted to the Graduate College of Texas A & M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December, 1986 Major Subject; Mechanical Engineering AN INVESTIGATION OF STRESS CONC~TION EFFECTS IN WELDING ELBOWS A Thesis by MIKE WAYNE BALLARD Approved as to style and content by; Mog Henriksen (Ch ' of Committee) Joh J. (Me er) lorn Brya L...

  17. Diode laser welding of aluminum to steel

    SciTech Connect (OSTI)

    Santo, Loredana; Quadrini, Fabrizio; Trovalusci, Federica [University of Rome Tor Vergata, Department of Mechanical Engineering, Via del Politecnico 1, 00133 Rome (Italy)

    2011-05-04T23:59:59.000Z

    Laser welding of dissimilar materials was carried out by using a high power diode laser to join aluminum to steel in a butt-joint configuration. During testing, the laser scan rate was changed as well as the laser power: at low values of fluence (i.e. the ratio between laser power and scan rate), poor joining was observed; instead at high values of fluence, an excess in the material melting affected the joint integrity. Between these limiting values, a good aesthetics was obtained; further investigations were carried out by means of tensile tests and SEM analyses. Unfortunately, a brittle behavior was observed for all the joints and a maximum rupture stress about 40 MPa was measured. Apart from the formation of intermeltallic phases, poor mechanical performances also depended on the chosen joining configuration, particularly because of the thickness reduction of the seam in comparison with the base material.

  18. A digital Rykalin function for welding

    SciTech Connect (OSTI)

    Bertram, L.A.

    1996-12-01T23:59:59.000Z

    This document outlines the software written to enable a user to evaluate the analytical solutions developed by N.N.Rykalin (1947) for the temperature rise created by moving a heat source of a given power over a workpiece. His solution is extended here so that an arbitrary weld schedule can be prescribed by the user. The inputs are thermophysical properties of the workpiece, and the schedule, in the form of piecewise constant power supply voltage, current and travel speed. The user also specifies the position of the point, and the elapsed time for which the output temperature rise is desired. An optional plot file for the temperature along the travel direction is also provided.

  19. actinide separations optimized: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (more) Potter, Michael Wayne 1981-01-01 2 Optimal distance separating halfspace Optimization Online Summary: which uses a proof based on the Kuhn-Tucker conditions). Corollary...

  20. Corrosion Resistant Cladding by YAG Laser Welding in Underwater Environment

    SciTech Connect (OSTI)

    Tsutomi Kochi; Toshio Kojima; Suemi Hirata; Ichiro Morita; Katsura Ohwaki [Ishikawajima-Harima Heavy Industries Company Ltd., 1 Shin-Nakaharacho, Isogoku, Yokohama 235-8501 (Japan)

    2002-07-01T23:59:59.000Z

    It is known that stress-corrosion cracking (SCC) will occur in nickel-base alloys used in Reactor Pressure Vessel (RPV) and Internals of nuclear power plants. A SCC sensitivity has been evaluated by IHI in each part of RPV and Internals. There are several water level instrumentation nozzles installed in domestic BWR RPV. In water level instrumentation nozzles, 182 type nickel-base alloys were used for the welding joint to RPV. It is estimated the SCC potential is high in this joint because of a higher residual stress than the yield strength (about 400 MPa). This report will describe a preventive maintenance method to these nozzles Heat Affected Zone (HAZ) and welds by a corrosion resistant cladding (CRC) by YAG Laser in underwater environment (without draining a reactor water). There are many kinds of countermeasures for SCC, for example, Induction Heating Stress Improvement (IHSI), Mechanical Stress Improvement Process (MSIP) and so on. A YAG laser CRC is one of them. In this technology a laser beam is used for heat source and irradiated through an optical fiber to a base metal and SCC resistant material is used for welding wires. After cladding the HAZ and welds are coated by the corrosion resistant materials so their surfaces are improved. A CRC by gas tungsten arc welding (GTAW) in an air environment had been developed and already applied to a couple of operating plants (16 Nozzles). This method was of course good but it spent much time to perform because of an installation of some water-proof working boxes to make a TIG-weldability environment. CRC by YAG laser welding in underwater environment has superior features comparing to this conventional TIG method as follows. At the viewpoint of underwater environment, (1) an outage term reduction (no drainage water). (2) a radioactive exposure dose reduction for personnel. At that of YAG laser welding, (1) A narrower HAZ. (2) A smaller distortion. (3) A few cladding layers. A YAG laser CRC test in underwater environment was carried out in the different welding position, horizontal, vertical upward and downward. The soundness of cladding layers (about 3 mm) is confirmed in visual and penetration test, and cross section observation. In the application to the actual plants, it is preferable to reduce the start and end point numbers of beads with which a defect is easy to cause. Therefore a special welding equipment for a YAG laser CRC that could weld continuously was developed. (authors)

  1. Irradiation effects on fracture toughness of two high-copper submerged-arc welds, HSSI Series 5. Volume 1, Main report and Appendices A, B, C, and D

    SciTech Connect (OSTI)

    Nanstad, R.K.; Haggag, F.M.; McCabe, D.E.; Iskander, S.K.; Bowman, K.O. [Oak Ridge National Lab., TN (United States); Menke, B.H. [Materials Engineering Associates, Inc., Lanham, MD (United States)

    1992-10-01T23:59:59.000Z

    The Fifth Irradiation Series in the Heavy-Section Steel Irradiation Program obtained a statistically significant fracture toughness data base on two high-copper (0.23 and 0.31 wt %) submerged-arc welds to determine the shift and shape of the K{sub Ic} curve as a consequence of irradiation. Compact specimens with thicknesses to 101.6 mm (4 in) in the irradiated condition and 203.2 mm (8 in) in the unirradiated condition were tested, in addition to Charpy impact, tensile, and drop-weight specimens. Irradiations were conducted at a nominal temperature of 288{degree}C and an average fluence of 1.5 {times} 10{sup 19} neutrons/cm{sup 2} (>l MeV). The Charpy 41-J temperature shifts are about the same as the corresponding drop-weight NDT temperature shifts. The irradiated welds exhibited substantial numbers of cleavage pop-ins. Mean curve fits using two-parameter (with fixed intercept) nonlinear and linearized exponential regression analysis revealed that the fracture toughness 100 MPa{lg_bullet}{radical}m shifts exceeded the Charpy 41-J shifts for both welds. Analyses of curve shape changes indicated decreases in the slopes of the fracture toughness curves, especially for the higher copper weld. Weibull analyses were performed to investigate development of lower bound curves to the data, including the use of a variable K{sub min} parameter which affects the curve shape.

  2. OPTIMIZATION TOPICS LIST Revised April 2012

    E-Print Network [OSTI]

    Radeloff, Volker C.

    1 OPTIMIZATION TOPICS LIST Revised April 2012 For Fall 2012 and Spring 2013 we will adopt. Bertsimas and J. Tsitsiklis, Introduction to Linear Optimization, Athena Scientific, 1997 2. M. C. Ferris, O and mixed integer models · Existence of optimal solutions, optimality conditions · Branch and bound methods

  3. Repair welding of fusion reactor components. Final technical report

    SciTech Connect (OSTI)

    Chin, B.A.; Wang, C.A.

    1997-09-30T23:59:59.000Z

    The exposure of metallic materials, such as structural components of the first wall and blanket of a fusion reactor, to neutron irradiation will induce changes in both the material composition and microstructure. Along with these changes can come a corresponding deterioration in mechanical properties resulting in premature failure. It is, therefore, essential to expect that the repair and replacement of the degraded components will be necessary. Such repairs may require the joining of irradiated materials through the use of fusion welding processes. The present ITER (International Thermonuclear Experimental Reactor) conceptual design is anticipated to have about 5 km of longitudinal welds and ten thousand pipe butt welds in the blanket structure. A recent study by Buende et al. predict that a failure is most likely to occur in a weld. The study is based on data from other large structures, particularly nuclear reactors. The data used also appear to be consistent with the operating experience of the Fast Flux Test Facility (FFTF). This reactor has a fuel pin area comparable with the area of the ITER first wall and has experienced one unanticipated fuel pin failure after two years of operation. The repair of irradiated structures using fusion welding will be difficult due to the entrapped helium. Due to its extremely low solubility in metals, helium will diffuse and agglomerate to form helium bubbles after being trapped at point defects, dislocations, and grain boundaries. Welding of neutron-irradiated type 304 stainless steels has been reported with varying degree of heat-affected zone cracking (HAZ). The objectives of this study were to determine the threshold helium concentrations required to cause HAZ cracking and to investigate techniques that might be used to eliminate the HAZ cracking in welding of helium-containing materials.

  4. Ultrasonic inspection of austenitic stainless steel welds with artificially produced stress corrosion cracks

    SciTech Connect (OSTI)

    Dugan, Sandra; Wagner, Sabine [Materials Testing Institute University of Stuttgart (MPA), Pfaffenwaldring 32, 70569 Stuttgart (Germany)

    2014-02-18T23:59:59.000Z

    Austenitic stainless steel welds and nickel alloy welds, which are widely used in nuclear power plants, present major challenges for ultrasonic inspection due to the grain structure in the weld. Large grains in combination with the elastic anisotropy of the material lead to increased scattering and affect sound wave propagation in the weld. This results in a reduced signal-to-noise ratio, and complicates the interpretation of signals and the localization of defects. Mechanized ultrasonic inspection was applied to study austenitic stainless steel test blocks with different types of flaws, including inter-granular stress corrosion cracks (IGSCC). The results show that cracks located in the heat affected zone of the weld are easily detected when inspection from both sides of the weld is possible. In cases of limited accessibility, when ultrasonic inspection can be carried out only from one side of a weld, it may be difficult to distinguish between signals from scattering in the weld and signals from cracks.

  5. The hardening of Type 316L stainless steel welds with thermal aging

    E-Print Network [OSTI]

    Ayers, Lauren Juliet

    2012-01-01T23:59:59.000Z

    Welded stainless steel piping is a component of boiling water reactors (BWRs). Reirculation and other large diameter piping are fabricated from Type 304 or 316 stainless steels. Delta ferrite is present in welds, because ...

  6. Welding of cast A359/SiC/10p metal matrix composites

    E-Print Network [OSTI]

    Kothari, Mitul Arvind

    2005-11-01T23:59:59.000Z

    Welding of metal matrix composites (MMCs) is an alternative to their mechanical joining, since they are difficult to machine. Published literature in fusion welding of similar composites shows metallurgical problems. This study investigates...

  7. Vehicle Technologies Office Merit Review 2014: On-Line Weld NDE...

    Broader source: Energy.gov (indexed) [DOE]

    On-Line Weld NDE with IR Thermography Vehicle Technologies Office Merit Review 2014: On-Line Weld NDE with IR Thermography Presentation given by Oak Ridge National Laboratory at...

  8. Reasons for superior mechanical and corrosion properties of 2219 aluminum alloy electron beam welds

    SciTech Connect (OSTI)

    Koteswara Rao, S.R. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India)]. E-mail: sajjarkr@yahoo.com; Madhusudhan Reddy, G. [Defense Metallurgical Research Laboratory, Hyderabad-500 058 (India); Srinivasa Rao, K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India); Kamaraj, M. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India); Prasad Rao, K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India)

    2005-11-15T23:59:59.000Z

    Electron beam welds of aluminum alloy 2219 offer much higher strength compared to gas tungsten arc welds of the same alloy and the reasons for this have not been fully explored. In this study both types of welds were made and mechanical properties were evaluated by tensile testing and pitting corrosion resistance by potentio dynamic polarization tests. It is shown that electron beam welds exhibit superior mechanical and corrosion properties. The weld metals have been characterized by scanning electron microscopy; transmission electron microscopy and electron probe micro analysis. Presence of partially disintegrated precipitates in the weld metal, finer micro porosity and uniform distribution of copper in the matrix were found to be the reasons for superior properties of electron beam welds apart from the fine equiaxed grain structure. Transmission electron micrographs of the heat affected zones revealed the precipitate disintegration and over aging in gas tungsten arc welds.

  9. Conditional Gradient Sliding for Convex Optimization

    E-Print Network [OSTI]

    2014-10-17T23:59:59.000Z

    Oct 17, 2014 ... To the best of our knowledge, this is the first time that ... Department of Industrial and Systems Engineering, University of Florida, Gainesville,...

  10. Optimization Online - Sufficient and Necessary Conditions for ...

    E-Print Network [OSTI]

    J. William Helton

    2007-10-15T23:59:59.000Z

    Oct 15, 2007 ... This provides a technique for building global SDP representations from the local ones. (ii) For the SDP representability of a compact convex...

  11. Slag-Metal Reactions during Welding: Part II. Theory ) U. MITRA and T.W. EAGAR

    E-Print Network [OSTI]

    Eagar, Thomas W.

    Slag-Metal Reactions during Welding: Part II. Theory ) U. MITRA and T.W. EAGAR A kinetic model-shielded welding. The model ac~o~nts .for changes i~ ~lloy r~covery based on the geometry of the resulting weld bead. It also dtstmgUJshes compos1t1onal dtfferences be- tween single-pass and multiple-pass weld beads

  12. Effect of Microstructure on Mechanical Properties of High Strength Steel Weld Metals

    E-Print Network [OSTI]

    Keehan, Enda

    2004-01-01T23:59:59.000Z

    using for example gas tungsten arc welding (GTAW). However as strength levels increase it becomes more difficult to fulfil impact toughness requirements with flexible and productive welding methods such as shielded metal arc welding (SMAW), flux cored... . Little effects are seen on the cross sectional area of each weld bead deposited with increase in interpass temperature but the proportion of recrystallised area increases [12]. By eliminating the columnar microstructure, hardness becomes more uniform...

  13. Welding of cast A359/SiC/10p metal matrix composites

    E-Print Network [OSTI]

    Kothari, Mitul Arvind

    2005-11-01T23:59:59.000Z

    the weldability of the MMC in this study refers to analyzing the microstructure of the welded MMC and evaluating their properties as a function of the input variables. This necessarily did not mean to make a full penetration butt joint; it rather was intended... of experiments (DOE). Factorial experiments are to be conducted to screen the non-significant variables and to choose comparatively significant welding variables. 2. Welding, testing, and evaluation methods It is proposed to weld these MMCs by a...

  14. Optimization Neuroimaging'',

    E-Print Network [OSTI]

    Nielsen, Finn ?rup

    Canonical Ridge Analysis with Ridge Parameter Optimization F. ?. Nielsen, L. K. Hansen and S. C - PLS 1 = k 0 = k optimal k k = optimal k k £ £ 0 #12; Canonical Ridge Analysis with Ridge Parameter Optimization F. ?. Nielsen, L. K. Hansen and S. C. Strother The Human Brain Project, P20 MH57180 ``Spatial

  15. Optimal Uncertainty Quantification

    E-Print Network [OSTI]

    Owhadi, Houman; Sullivan, Timothy John; McKerns, Mike; Ortiz, Michael

    2010-01-01T23:59:59.000Z

    We propose a rigorous framework for Uncertainty Quantification (UQ) in which the UQ objectives and the assumptions/information set are brought to the forefront. This framework, which we call \\emph{Optimal Uncertainty Quantification} (OUQ), is based on the observation that, given a set of assumptions and information about the problem, there exist optimal bounds on uncertainties: these are obtained as extreme values of well-defined optimization problems corresponding to extremizing probabilities of failure, or of deviations, subject to the constraints imposed by the scenarios compatible with the assumptions and information. In particular, this framework does not implicitly impose inappropriate assumptions, nor does it repudiate relevant information. Although OUQ optimization problems are extremely large, we show that under general conditions, they have finite-dimensional reductions. As an application, we develop \\emph{Optimal Concentration Inequalities} (OCI) of Hoeffding and McDiarmid type. Surprisingly, contr...

  16. A Concurrent Product-Development Approach for Friction-Stir Welded Vehicle-Underbody Structures

    E-Print Network [OSTI]

    Grujicic, Mica

    A Concurrent Product-Development Approach for Friction-Stir Welded Vehicle-Underbody Structures M technologies such as friction-stir welding (FSW) have to be employed. However, since FSW is a relatively new-survivable and ballistic threat-resistant military vehicles, friction-stir welding, process development 1. Introduction

  17. Modelling the Electron Beam Welding of Nuclear Reactor Pressure Vessel Steel

    E-Print Network [OSTI]

    Cambridge, University of

    Modelling the Electron Beam Welding of Nuclear Reactor Pressure Vessel Steel Christopher J. Duffy fabrication of thick-section steel for critical components such as reactor pressure vessels. Electron beam weld tests performed by Rolls-Royce and The Welding Institute of SA 508 Grade 3 and SA 508 Grade 4N

  18. Physical processes involved in strip electrode welding using the method of slatted splicing

    SciTech Connect (OSTI)

    Bushma, V. O. [Moscow State Technological University 'Stankin' (Russian Federation)

    2010-12-15T23:59:59.000Z

    Physical processes that take place in a strip electrode during welding using the slatted splicing technique are considered. Flowing of the welding current in the electrode is shown to be the key process which determines electrode heating and melting. Technological receipts are proposed that allow obtaining high-quality welds by the method of slatted splicing.

  19. Control Engineering Practice 11 (2003) 14011411 Modeling and control of quasi-keyhole arc welding process

    E-Print Network [OSTI]

    Zhang, YuMing

    Control Engineering Practice 11 (2003) 1401­1411 Modeling and control of quasi-keyhole arc welding to operate the keyhole arc welding process. Because the method's effectiveness depends on the amperage reserved. Keywords: Modeling; Predictive control; Manufacturing; Welding 1. Introduction Keyhole arc

  20. Hot tearing test for TIG welding of aluminum alloys: application of a stress parallel to the

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Page 1 Hot tearing test for TIG welding of aluminum alloys: application of a stress parallel or solidification cracking, in aluminum alloys welding is an important industrial issue and must be carefully the parameters leading to hot tearing during welding. The originality of the test presented here

  1. Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139

    E-Print Network [OSTI]

    Grujicic, Mica

    Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139 coupled thermo-mechanical finite-element analysis of the friction-stir welding (FSW) process developed, finite-element analysis, friction- stir welding, hardness prediction 1. Introduction Having a more mobile

  2. Adaptive Anisotropic Mesh Technique For Coupled Problems: Application To Welding Simulation

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Adaptive Anisotropic Mesh Technique For Coupled Problems: Application To Welding Simulation M, such as welding for instance, is the control of the mesh, that is an appropriate mastering of the spatial welding. We demonstrate that the use of an anisotropic adaptive finite element method can result

  3. PublishedbyManeyPublishing(c)IOMCommunicationsLtd Friction stir welding of dissimilar alloys a

    E-Print Network [OSTI]

    Cambridge, University of

    PublishedbyManeyPublishing(c)IOMCommunicationsLtd Friction stir welding of dissimilar alloys a perspective T. DebRoy*1 and H. K. D. H. Bhadeshia2 Friction stir welding does not involve bulk melting. The purpose of this special issue of Science and Technology of Welding and Joining was to assess the status

  4. 1. WELDING SHALL BE PERFORMED IN ACCORDANCE WITH ASME SECTION IX. NO CODE STAMP REQUIRED.

    E-Print Network [OSTI]

    McDonald, Kirk

    NOTES 1. WELDING SHALL BE PERFORMED IN ACCORDANCE WITH ASME SECTION IX. NO CODE STAMP REQUIRED. 2. ALL WELDS SHALL BE DYE PENETRANT INSPECTED. NO RADIOGRAPHY REQUIRED. 3. MATERIAL CERTIFICATIONS HOSE W/TUBING ENDS, 13.5 FACE-TO-FACE N/A 3 1 swagelok 1.0 pipe weld connector SS - 316L SWAGELOK PIPE

  5. Thermocapillary and Magnetohydrodynamic Effects in Modelling the Thermodynamics of Stationary Welding Processes

    E-Print Network [OSTI]

    Taylor, Gary

    Welding Processes Michael HUGHES, Gareth A. TAYLOR and Koulis PERICLEOUS Centre for Numerical Modelliqng transport and solidification in a stationary axisymmetric weld pool. The PHOENICS implementations, the integration of the effects within the fluid dynamics of an axisymmetric weld pool is compared against

  6. FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA

    E-Print Network [OSTI]

    Taylor, Gary

    1 FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA Gareth A.Taylor@brunel.ac.uk ABSTRACT This paper presents the computational modelling of welding phenomena within a versatile numerical) and Computational Solid Mechanics (CSM). With regard to the CFD modelling of the weld pool fluid dynamics, heat

  7. Friction Stir Welding of Hydrided Titanium Alloys Mark Taylor, D.P. Field

    E-Print Network [OSTI]

    Collins, Gary S.

    Friction Stir Welding of Hydrided Titanium Alloys Mark Taylor, D.P. Field Multi-Scale Engineering for Undergraduates program under grant number EEC-0754370 During Friction Stir Welding (FSW), a non-consumable tool-state welding process, much frictional heating and force is required of the tool. This steep demand on the tool

  8. WELDING INSPECTION USING NOVEL SPECULARITY FEATURES AND A ONE-CLASS SVM

    E-Print Network [OSTI]

    WELDING INSPECTION USING NOVEL SPECULARITY FEATURES AND A ONE-CLASS SVM Fabian Timm, Sascha Klement extraction, One-class classification, Welding seam inspection, Machine vision. Abstract: We present a framework for automatic inspection of welding seams based on specular reflections. Therefore, we introduce

  9. RRR Degradation and Gas Absorption in the Electron Beam Welding Area of High Purity

    E-Print Network [OSTI]

    1 RRR Degradation and Gas Absorption in the Electron Beam Welding Area of High Purity Niobium W degradation and gas absorption of high purity niobium welded at different electron beam (EB) facilities are summarized. The oxygen and nitrogen content is increased as a rule at the welding seam. The absorption

  10. Comparison of alloying concepts for Low Transformation Temperature (LTT) welding consumables

    E-Print Network [OSTI]

    Cambridge, University of

    Comparison of alloying concepts for Low Transformation Temperature (LTT) welding consumables L. Karlsson1 , L. Mrz2 , H. K. D. H. Bhadeshia3 and A. A. Shirzadi4 1 ESAB AB, Gteborg, Sweden 2 Welding Abstract Fatigue cracks often initiate at welds as a consequence of large residual stresses and changes

  11. Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding sources for finite element simulation of gas metal arc welding (GMAW). Design for the modeling of metal deposition results in a direct calculation of the formation of the weld bead, without any

  12. Rheology of welding: inversion of field constraints James K. Russell*, Steven L. Quane

    E-Print Network [OSTI]

    Russell, Kelly

    Rheology of welding: inversion of field constraints James K. Russell*, Steven L. Quane Igneous the mechanisms and rheological behaviour of pyroclastic deposits during welding and compaction are poorly are constrained by physical property distributions in welded ignimbrite. Physical properties of samples from a 20

  13. IDENTIFICATION NUMBER: 4ME20 Abstract--Artificial welding of melt-textured YBCO blocks

    E-Print Network [OSTI]

    Politcnica de Catalunya, Universitat

    1 IDENTIFICATION NUMBER: 4ME20 Abstract--Artificial welding of melt-textured YBCO blocks opens the superconducting quality of the welds, we have developed a Hall probe mapping system, able to record the local to characterize welded samples prepared with a new Ag induced surface melting joining technique. The magnetization

  14. Error Estimation And Accurate Mapping Based ALE Formulation For 3D Simulation Of Friction Stir Welding

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Welding Simon Guerdoux, Lionel Fourment* CEMEF, Mines cle Paris, BP 207, 06 904 Sophia Antipolis Ceclex) formulation is developed to simulate the different stages of the Friction Stir Welding (FSW) process standard approaches. The proposed ALE formulation is applied to FSW simulation. Steady state welding

  15. The Geometry of Intersecting Tubes Applied to Controlling a Robotic Welding Torch

    E-Print Network [OSTI]

    Stockie, John

    The Geometry of Intersecting Tubes Applied to Controlling a Robotic Welding Torch John M. Stockie Abstract: The question of how to control a robotic welding torch to trace the joint between two cylindrical that increase its applicability to more advanced mathematics courses. Keywords: pipe welding, cylinders

  16. Computational Analysis of Material Flow During Friction Stir Welding of AA5059 Aluminum Alloys

    E-Print Network [OSTI]

    Grujicic, Mica

    Computational Analysis of Material Flow During Friction Stir Welding of AA5059 Aluminum Alloys M welding (FSW) process are investigated computationally. Within the numerical model of the FSW process component. The employed coupled Eulerian/Lagrangian computational analysis of the welding process

  17. A functional-analytic proof of the conformal welding Eric Schippers1 Wolfgang Staubach 2

    E-Print Network [OSTI]

    Schippers, Eric

    A functional-analytic proof of the conformal welding theorem Eric Schippers1 Wolfgang Staubach 2 1 Universitet Uppsala, Sweden CMS Winter Meeting 2012 Eric Schippers (Manitoba) Conformal welding theorem CMS Winter Meeting 2012 1 / 21 #12;Statement of the theorem Conformal welding theorem Definition

  18. Slag Metal Reactions in Binary CaF2-Metal Oxide Welding Fluxes

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) Slag Metal Reactions in Binary CaF2-Metal Oxide Welding Fluxes Some otherwise chemically stable fluxes may decompose into suboxides in the presence of welding arcs, thereby providing higher levels of 0 2 in weld metal than those oxides which do not form suboxides ABSTRACT. The stability of metal

  19. Recent Advances in Friction Stir Welding Process, Weldment Structure and Properties

    E-Print Network [OSTI]

    Cambridge, University of

    Recent Advances in Friction Stir Welding Process, Weldment Structure and Properties R. Nandan, T University of Cambridge, Cambridge CB2 3QZ, U.K. Abstract Friction stir welding is a refreshing approach flow during welding, elements of tool design, understanding defect formation and the structure

  20. A Walk-Through Programmed Robot for Welding in Shipyards Marcelo H. Ang Jr.*, Wei Lin#

    E-Print Network [OSTI]

    Ang Jr.,, Marcelo H.

    1 A Walk-Through Programmed Robot for Welding in Shipyards Marcelo H. Ang Jr.*, Wei Lin# and Ser: Walk-through programming Robotic welding Automation in shipyards Dynamic control Industrial Robot, Vol. 26, No. 5, 1999, pp. 377-388. #12;1 A Walk-Through Programmed Robot for Welding in Shipyards

  1. Global sensitivity analysis in welding simulations --what are the material data you really need ?

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Global sensitivity analysis in welding simulations -- what are the material data you really need methodology is applied to numerical welding simulation in order to rank the importance of input variables on the outputs of the code like distorsions or residual stresses. The numerical welding simulation uses

  2. Process Modeling of Ti-6Al-4V Linear Friction Welding (LFW)

    E-Print Network [OSTI]

    Grujicic, Mica

    Process Modeling of Ti-6Al-4V Linear Friction Welding (LFW) Mica Grujicic, G. Arakere, B finite-element analysis of the linear friction welding (LFW) process is combined with the basic physical in the open literature revealed that the weld region consists of a thermo- mechanically affected zone (TMAZ

  3. Diode Laser Welding of ABS: Experiments and Process Modelling , E.CICALA1,2

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Diode Laser Welding of ABS: Experiments and Process Modelling M.ILIE1,3 , E.CICALA1,2 , D.GREVEY2 for Welding and Material Testing, 30, Mihai Viteazul Bv, 300222 Timisoara, Romania Abstract In the present.ilie@mec.upt.ro, milie@isim.ro Keywords: Laser welding; Semitransparent Polymers; Numerical simulation; Experimental

  4. ~DELING OF METAL TRANSFKR IN GAS METAL ARC WELDING Yong -Seog Kim and T. W. Eagar

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) ) ~DELING OF METAL TRANSFKR IN GAS METAL ARC WELDING Yong -Seog Kim and T. W. Eagar theory and the pinch i ns t a bility theor y as a function of welding cur rent . Experimental of the gas metal arc process in the late 1940s, it has become one of the most important welding processes

  5. RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS Kyunghan Kim to incorporate transient radiation heat transfer in tissue welding and soldering with use of ultrafast lasers are performed between laser welding and laser soldering. The use of solder is found to substantially enhance

  6. Hot tearing test for TIG welding of aluminum alloys: application of a stress parallel to the

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Page 1 Hot tearing test for TIG welding of aluminum alloys: application of a stress parallel in aluminum alloys welding is an important industrial issue. Understanding of hot cracking phenomenon welding. The originality of the test presented here is that an external stress is applied on the test

  7. DOI: 10.1002/adem.201100211 Atomistic Simulation of the Explosion Welding Process**

    E-Print Network [OSTI]

    Nordlund, Kai

    DOI: 10.1002/adem.201100211 Atomistic Simulation of the Explosion Welding Process** By Ossi Saresoja, Antti Kuronen* and Kai Nordlund Explosive welding (EXW) is an industrial process used to join. In the process, welding occurs in a high velocity collision between metal plates, achieved by using chemical

  8. A COUPLED APPROACH FOR THE MODELLING OF ARC WELDING Christel Pequet1

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    A COUPLED APPROACH FOR THE MODELLING OF ARC WELDING PROCESSES Christel Pequet1 , Patrice Lasne1 ; email : michel.bellet@ensmp.fr Keywords: welding, finite elements, thermal arising in arc welding as well as their interaction: heat input, metal deposit, solidification, phase

  9. Welding processes in volcanology: insights from field, experimental, and modeling studies

    E-Print Network [OSTI]

    Russell, Kelly

    Welding processes in volcanology: insights from field, experimental, and modeling studies Anita This volume is a collection of ten papers largely derived from a special session, Welding Processes, experimental, and modeling studies. We briefly review advances in understanding welding as represented

  10. Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D

    E-Print Network [OSTI]

    Zhou, Wei

    Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D W. Zhou*, T. Z. Long and C. K of the plates were produced using tungsten inert gas (TIG) welding method. The TIG arc was also used to deposit welding beads on some of the thin plates. No cracking was found in the butt joints. However, hot cracking

  11. Improved Microstructure and Properties of 6061 Aluminum Alloy Weldments Using a Double-Sided Arc Welding

    E-Print Network [OSTI]

    Zhang, YuMing

    Welding Process Y.M. ZHANG, C. PAN, and A.T. MALE Due to its popularity and high crack sensitivity, 6061 aluminum alloy was selected as a test material for the newly developed double-sided arc welding (DSAW systematically. The percentage of fine equiaxed grains in the fully penetrated welds is greatly increased

  12. Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding M. Grujicic yet a fairly comprehensive overview of the friction stir welding (FSW) process is provided-element procedure developed in our prior study. Particular attention is given to proper modeling of the welding work

  13. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Welding M. Grujicic, S. Ramaswami, J.S. Snipes, R. Yavari, A. Arakere, C.-F. Yen, and B.A. Cheeseman-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt of the workpiece and the weld temperature- dependent and by allowing the potential work of plastic deformation

  14. Welding: insights from high-temperature analogue experiments Steven L. Quane, J.K. Russell*

    E-Print Network [OSTI]

    Russell, Kelly

    Welding: insights from high-temperature analogue experiments Steven L. Quane, J.K. Russell* Igneous of pyroclastic deposits during welding is incompletely understood and is based on a surprisingly small number roles of emplacement temperature, load and glass transition temperature in welding of pyroclastic

  15. Neural network analysis of strength and ductility of welding alloys for high strength low

    E-Print Network [OSTI]

    Cambridge, University of

    Neural network analysis of strength and ductility of welding alloys for high strength low alloy There are considerable demands for the development of weld metals for high strength low alloy steels. To assist in meeting such demands, a neural network was trained and tested on a set of data obtained on weld metals

  16. SF 2001-WLD (11-2012) Supersedes (4-2010) Issue CONTRACTOR WELDING, CUTTING, BRAZING

    E-Print Network [OSTI]

    SF 2001-WLD (11-2012) Supersedes (4-2010) Issue CONTRACTOR WELDING, CUTTING, BRAZING PART 1: CONTRACTOR'S EXPOSURE ASSESSMENT Identify what welding, cutting and/or brazing you are doing: (Check box or fill-in type below) Welding Thermal Cutting Brazing (No cadmium filler BAg-1 or BAg- 2; Silver

  17. Induction welding and heat treatment of steel pipes: evolution of crystallographic texture

    E-Print Network [OSTI]

    Cambridge, University of

    Induction welding and heat treatment of steel pipes: evolution of crystallographic texture detrimental to toughness P. Yan*1 , O. E. Gungor2 , P. Thibaux2 and H. K. D. H. Bhadeshia1 Steel welding using induction heating to produce pipelines is found to have lower toughness at the weld junction than

  18. Reliability of Laser Welding Process for ZE41A-T5 Magnesium Alloy Sand Castings

    E-Print Network [OSTI]

    Medraj, Mamoun

    Reliability of Laser Welding Process for ZE41A-T5 Magnesium Alloy Sand Castings Haider Al-Kazzaz1, National Research Council Canada, Montreal, Canada Laser welding is a promising joining method for magnesium alloys. The process reliability of 2-mm ZE41A-T5 butt joints welded by a 4 kW Nd:YAG laser

  19. Effects of weld preheat temperature and heat input on type IV failure

    E-Print Network [OSTI]

    Cambridge, University of

    Effects of weld preheat temperature and heat input on type IV failure J. A. Francis*1 , G. M. D of a welded joint due to an enhanced rate of creep void formation in the fine grained or intercritically standpoint, and comparatively little effort has been directed at understanding the effects of welding

  20. An Analysis of Heat and Fluid Flow Phenomena 1n Electroslag Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    and temperature distri- bution~ are given for several idealized models of the electroslag welding process) ) An Analysis of Heat and Fluid Flow Phenomena 1n Electroslag Welding Two physical models created and fluid flow phenom- ena in metals processing operations have been applied to electroslag weld- ing

  1. HIGH TEMPERATURE CREEP PROPERTIES AND MICROSTRUCTURAL EXAMINATIONS OF P92 WELDS

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    1 HIGH TEMPERATURE CREEP PROPERTIES AND MICROSTRUCTURAL EXAMINATIONS OF P92 WELDS Kalck Charlotte1 for high temperature components and especially for welded components. Its main targeted applications: charlotte.kalck@cea.fr Abstract The present study deals with the creep properties of welded joints made of P

  2. Hot-crack test for aluminium alloys welds using TIG process , F. Deschaux1

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Hot-crack test for aluminium alloys welds using TIG process A. Niel1,a , F. Deschaux1 , C cracking in welds : state of art Aluminium alloys are highly sensitive to hot tearing phenomenon. It appears during solidification of the alloy, so it can be observed during welding, as well as during

  3. FILL STEM MANUFACTURING CHANGES AND PINCH WELD QUALIFICATIONS

    SciTech Connect (OSTI)

    Korinko, P; David Maxwell, D

    2008-02-22T23:59:59.000Z

    In March of 2007 a document was issued, see attachment I, that defined the test protocol and required welding for the Kansas City Plant to change cutting oils from the recently approved 50:50 oil to an oil with similar characteristics but with different chemistry, additives, and possibly a different vendor due to plans by the current vendor to stop preparing the oils that are used in the KCP 50:50 mix. The KCP manufactured stems with the existing 50:50 oil blend in late FY07 and SRNL welded the stems and evaluated them in agreement with the test plan. This report provides all the data from these set-up and test welds. Set-up welds were shot and low and high voltages (currents) to ensure the window limits were applicable and then additional welds were made to validate the window. The purpose of this report is to ensure that the agreed upon path forward is still applicable.

  4. TEMPORARILY ALLOYING TITANIUM TO FACILITATE FRICTION STIR WELDING

    SciTech Connect (OSTI)

    Hovanski, Yuri

    2009-05-06T23:59:59.000Z

    While historically hydrogen has been considered an impurity in titanium, when used as a temporary alloying agent it promotes beneficial changes to material properties that increase the hot-workability of the metal. This technique known as thermohydrogen processing was used to temporarily alloy hydrogen with commercially pure titanium sheet as a means of facilitating the friction stir welding process. Specific alloying parameters were developed to increase the overall hydrogen content of the titanium sheet ranging from commercially pure to 30 atomic percent. Each sheet was evaluated to determine the effect of the hydrogen content on process loads and tool deformation during the plunge phase of the friction stir welding process. Two materials, H-13 tool steel and pure tungsten, were used to fabricate friction stir welding tools that were plunged into each of the thermohydrogen processed titanium sheets. Tool wear was characterized and variations in machine loads were quantified for each tool material and weld metal combination. Thermohydrogen processing was shown to beneficially lower plunge forces and stabilize machine torques at specific hydrogen concentrations. The resulting effects of hydrogen addition to titanium metal undergoing the friction stir welding process are compared with modifications in titanium properties documented in modern literature. Such comparative analysis is used to explain the variance in resulting process loads as a function of the initial hydrogen concentration of the titanium.

  5. Analysis of effect of temperature gradients on surface-tension phenomena in gas-tungsten-arc welds

    SciTech Connect (OSTI)

    Lee, H.A.; Chien, P.S.J.

    1982-10-01T23:59:59.000Z

    Fluid motion directed by surface tension is considered as a contributor to heat penetration in a weld pool. The potential phenomena at the gas-liquid interface were analyzed, and the dependence of surface motion on temperature in the gas-tungsten-arc (GTA) welding process was examined. An existing heat-transfer model was used and was able to predict weld size to +- 50% of the actual value. A momentum-transfer equation was derived by considering the contribution of Lorentz force. The momentum boundary condition was developed and was able to predict the Marangoni effect. The magnitude of surface-tension-driven force is comparable to the gravitational force on one gram. An empirical approach was proposed to couple heat-transfer and momentum-transfer phenomena. A dimensional analysis identified the pertinent dimensionless groups as Reynolds, Weber, Froude, Peclet, and Power numbers and a dimensionless velocity. A simplified form of the correction was developed by combining dimensionless groups to yield a correlation with the Bond, Prandtl, and modified power numbers. Future experimental work was proposed to test the functionality of the dimensionless groups.

  6. Multiphysics Modeling and Simulations of Mil A46100 Armor-Grade Martensitic Steel Gas Metal Arc Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Welding Process M. Grujicic, S. Ramaswami, J.S. Snipes, C.-F. Yen, B.A. Cheeseman, and J.S. Montgomery developed for the conventional Gas Metal Arc Welding (GMAW) joining process and used to analyze butt-welding modules, each covering a specific aspect of the GMAW process, i.e., (a) dynamics of welding-gun behavior

  7. PERMIT FOR WELDING AND CUTTING OPERATIONS INSTRUCTIONS: This permit must be completed for all operations involving open

    E-Print Network [OSTI]

    Papautsky, Ian

    PERMIT FOR WELDING AND CUTTING OPERATIONS INSTRUCTIONS: This permit must be completed for all/Area: Description of Work to be Performed: (check where appropriate) Welding Cutting Soldering Burning Type OF ACCIDENTAL FIRES DUE TO WELDING OR CUTTING OPERATIONS 1: Do not perform cutting or welding work where an open

  8. The occupational endorsement certification in welding and materials technology is designed for beginning students who want to learn to

    E-Print Network [OSTI]

    Ickert-Bond, Steffi

    WELDING & MATERIALS TECHNOLOGY The occupational endorsement certification in welding and materials technology is designed for beginning students who want to learn to cut and weld, as well as students seeking more advanced courses who would like to take their welding skills further. Our program emphasizes

  9. The eects of dilution and base plate strength on stress distributions in multi-pass welds deposited using low

    E-Print Network [OSTI]

    Cambridge, University of

    ciently low temperature to compensate for accumulated thermal contraction strains. However, the welding not be exhausted until the weld cools to ambient temperature. This usually means that the weld metal should at an elevated temperature, further thermal contraction will lead to a build up of tensile stress as the weld

  10. Friction Stir Welding of Mild Steel -Tool Durability and Steel Microstructure , H. K. D. H. Bhadeshia2

    E-Print Network [OSTI]

    Cambridge, University of

    in the context of welding difficult aluminium alloys. We now apply this scheme to the friction stir welding for the welding of 7075 aluminium alloy.15 The results of the analysis were presented in the form of maps and the consequences on the physical metallurgy of the steel. Introduction Friction stir welding (FSW) of aluminium

  11. Prediction of Weld Penetration in FCAW of HSLA steel using Artificial Neural Networks

    SciTech Connect (OSTI)

    Asl, Y. Dadgar; Mostafa, N. B.; Panahizadeh, V. R. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Seyedkashi, S. M. H. [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2011-01-17T23:59:59.000Z

    Flux-cored arc welding (FCAW) is a semiautomatic or automatic arc welding process that requires a continuously-fed consumable tubular electrode containing a flux. The main FCAW process parameters affecting the depth of penetration are welding current, arc voltage, nozzle-to-work distance, torch angle and welding speed. Shallow depth of penetration may contribute to failure of a welded structure since penetration determines the stress-carrying capacity of a welded joint. To avoid such occurrences; the welding process parameters influencing the weld penetration must be properly selected to obtain an acceptable weld penetration and hence a high quality joint. Artificial neural networks (ANN), also called neural networks (NN), are computational models used to express complex non-linear relationships between input and output data. In this paper, artificial neural network (ANN) method is used to predict the effects of welding current, arc voltage, nozzle-to-work distance, torch angle and welding speed on weld penetration depth in gas shielded FCAW of a grade of high strength low alloy steel. 32 experimental runs were carried out using the bead-on-plate welding technique. Weld penetrations were measured and on the basis of these 32 sets of experimental data, a feed-forward back-propagation neural network was created. 28 sets of the experiments were used as the training data and the remaining 4 sets were used for the testing phase of the network. The ANN has one hidden layer with eight neurons and is trained after 840 iterations. The comparison between the experimental results and ANN results showed that the trained network could predict the effects of the FCAW process parameters on weld penetration adequately.

  12. Microstructural, mechanical and weldability assessments of the dissimilar welds between ??- and ??-strengthened nickel-base superalloys

    SciTech Connect (OSTI)

    Naffakh Moosavy, Homam, E-mail: homam_naffakh@iust.ac.ir [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran 16846-13114 (Iran, Islamic Republic of); Aboutalebi, Mohammad-Reza; Seyedein, Seyed Hossein [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran 16846-13114 (Iran, Islamic Republic of); Mapelli, Carlo [Dipartimento di Meccanica, Politecnico di Milano, Via La Massa 34, Milan 20156 (Italy)

    2013-08-15T23:59:59.000Z

    Dissimilar welding of ??- and ??-strengthened nickel-base superalloys has been investigated to identify the relationship between the microstructure of the welds and the resultant mechanical and weldability characteristics. ??-Strengthened nickel-base Alloy 500 and ??-strengthened nickel-base Alloy 718 were used for dissimilar welding. Gas tungsten arc welding operations were utilized for performing the autogenous dissimilar welding. Alloy 500 and Alloy 718 base metals showed various types of phases, carbides, intermetallics and eutectics in their microstructure. The results for Alloy 500 weld metal showed severe segregation of titanium to the interdendritic regions. The Alloy 718 weld metal compositional analysis confirmed the substantial role of Nb in the formation of low-melting eutectic-type morphologies which can reduce the weldability. The microstructure of dissimilar weld metal with dilution level of 65% wt.% displayed semi-developed dendritic structure. The less segregation and less formation of low-melting eutectic structures caused to less susceptibility of the dissimilar weld metal to the solidification cracking. This result was confirmed by analytic modeling achievements. Dissolution of ??-Ni{sub 3}Nb precipitations took place in the Alloy 718 heat-affected zone leading to sharp decline of the microhardness in this region. Remelted and resolidified regions were observed in the partially-melted zone of Alloy 500 and Alloy 718. Nevertheless, no solidification and liquation cracking happened in the dissimilar welds. Finally, this was concluded that dissimilar welding of ??- and ??-strengthened nickel-base superalloys can successfully be performed. - Highlights: Dissimilar welding of ??- and ??-strengthened nickel-base superalloys is studied. Microstructural, mechanical and weldability aspects of the welds are assessed. Microstructure of welds, bases and heat-affected zones is characterized in detail. The type, morphology and distribution of the phases are thoroughly investigated. Dissimilar welding is successfully performed without occurrence of any hot cracks.

  13. Method and device for controlling plume during laser welding

    DOE Patents [OSTI]

    Fuerschbach, Phillip W. (Tijeras, NM); Jellison, James L. (Albuquerque, NM); Keicher, David M. (Albuquerque, NM); Oberkampf, William L. (Albuquerque, NM)

    1991-01-01T23:59:59.000Z

    A method and apparatus for enhancing the weldment of a laser welding system is provided. The laser weld plume control device includes a cylindrical body defining an upside-down cone cavity; the upper surface of the body circumscribes the base of the cone cavity, and the vertex of the cone cavity forms an orifice concentrically located with respect to the laser beam and the plume which forms as a result of the welding operation. According to the method of the invention, gas is directed radially inward through inlets in the upper surface of the body into and through channels in the wall of the body and finally through the orifice of the body, and downward onto the surface of the weldment. The gas flow is then converted by the orifice of the device from radial flow to an axisymmetric gas jet flowing away from the weldment surface in a direction perpendicular to the surface and opposite to that of the laser.

  14. Gas-tungsten arc welding of aluminum alloys

    DOE Patents [OSTI]

    Frye, Lowell D. (Kingston, TN)

    1984-01-01T23:59:59.000Z

    A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  15. Gas-tungsten arc welding of aluminum alloys

    DOE Patents [OSTI]

    Frye, L.D.

    1982-03-25T23:59:59.000Z

    The present invention is directed to a gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to profice a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surface are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy continguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  16. Gas-tungsten arc welding of aluminum alloys

    SciTech Connect (OSTI)

    Frye, L.D.

    1984-11-20T23:59:59.000Z

    A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one micro-inch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  17. Fracture assessment of weld material from a full-thickness clad RPV shell segment

    SciTech Connect (OSTI)

    Keeney, J.A.; Bass, B.R.; McAfee, W.J.

    1996-07-01T23:59:59.000Z

    Fracture analysis was applied to full-thickness clad beam specimens containing shallow cracks in material for which metallurgical conditions are prototypic of those found in reactor pressure vessels (RPV) at beginning of life. The beam specimens were fabricated from a section of an RPV wall (removed from a canceled nuclear plant) that includes weld, plate, and clad material. Metallurgical factors potentially influencing fracture toughness for shallow cracks in the beam specimens include gradients of material properties and residual stresses due to welding and cladding applications. Fracture toughness estimates were obtained from load vs load-line displacement and load vs crack-mouth-opening displacement data using finite-element methods and estimation schemes based on the {eta}-factor method. One of the beams experienced a significant amount of precleavage stable ductile tearing. Effects of precleavage tearing on estimates of fracture toughness were investigated using continuum damage models. Fracture toughness results from the clad beam specimens were compared with other deep- and shallow-crack single-edge notch bend (SENB) data generated previously from A533 Grade B plate material. Range of scatter for the clad beam data is consistent with that from the laboratory-scale SENB specimens tested at the same temperature.

  18. Modeling solute redistribution and microstructural development in fusion welds of multi-component alloys

    SciTech Connect (OSTI)

    Dupont, J.N.; Robino, C.V.; Newbury, B.D.

    1999-12-15T23:59:59.000Z

    Solute redistribution and microstructural evolution have been modeled for gas tungsten arc fusion welds in experimental Ni base superalloys. The multi-component alloys were modeled as a pseudo-ternary {gamma}-Nb-C system. The variation in fraction liquid and liquid composition during the primary L {r{underscore}arrow} {gamma} and eutectic type L {r{underscore}arrow} ({gamma} + NbC) stages of solidification were calculated for conditions of negligible Nb diffusion and infinitely rapid C diffusion in the solid phase. Input parameters were estimated by using the Thermo-Calc NiFe Alloy data base and compared to experimentally determined solidification parameters. The solidification model results provide useful information for qualitatively interpreting the influence of alloy composition on weld microstructure. The quantitative comparisons indicate that, for the alloy system evaluated, the thermodynamic database provides sufficiently accurate values for the distribution coefficients of Nb and C. The calculated position of the {gamma}-NbC two-fold saturation line produces inaccurate results when used as inputs for the model, indicating further refinement to the database is needed for quantitative estimates.

  19. Detecting Weld Zone Over Anticorrosion Painting by Rotating Uniform Eddy Current Probe

    SciTech Connect (OSTI)

    Hoshikawa, H.; Koyama, K.; Naruse, Y. [Nihon University, Izumicho Narashino Chiba 275-8575 (Japan)

    2005-04-09T23:59:59.000Z

    The authors have studied application of rotating uniform eddy current probe to detecting weld zone in steed material over anticorrosion painting. The probe detects not only weld position by the signal level but also weld direction by the signal phase. The experimental results have indicated that the probe provides a signal almost linear to its position with respect to weld zone center over the full width of weld. The signal of the probe is much less influenced by the painting thickness variation than that of the conventional differential pancake-coils probe.

  20. Development of a Fiber Laser Welding Capability for the W76, MC4702 Firing Set

    SciTech Connect (OSTI)

    Samayoa, Jose

    2010-05-12T23:59:59.000Z

    Development work to implement a new welding system for a Firing Set is presented. The new system is significant because it represents the first use of fiber laser welding technology at the KCP. The work used Six-Sigma tools for weld characterization and to define process performance. Determinations of workable weld parameters and comparison to existing equipment were completed. Replication of existing waveforms was done utilizing an Arbitrary Pulse Generator (APG), which was used to modulate the fiber lasers exclusive continuous wave (CW) output. Fiber laser weld process capability for a Firing Set is demonstrated.