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Title: Characterization of welding residual stresses with neutron diffraction

Abstract

Welding residual stresses are a key concern in the fabrication and use of structural components containing welds. Residual stresses in welds are caused by non-uniform expansion and shrinkage of differently heated zones during the thermal transient of a weld pass. In some alloys, solid state phase transformations occurring during the welding transient contribute additional residual stresses. Manufacturing problems arising from welding residual stresses include cracking and dimensional distortion. During use, tensile stresses in the welded zone limit the fatigue resistance of the component under cyclic loading. In an aggressive environment, tensile welding residual stresses also create a necessary condition for stress-corrosion cracking to take place.

Authors:
; ; ;  [1];  [2]
  1. Oak Ridge National Lab., TN (United States)
  2. Edison Welding Inst., Columbus, OH (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States)
OSTI Identifier:
672109
Report Number(s):
ORNL/CP-97550; CONF-980627-
ON: DE98004895; BR: EE0403000; TRN: AHC2DT07%%269
DOE Contract Number:
AC05-96OR22464
Resource Type:
Technical Report
Resource Relation:
Conference: 1998 SEM spring conference on experimental and applied mechanics, Houston, TX (United States), 1-3 Jun 1998; Other Information: PBD: Mar 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RESIDUAL STRESSES; WELDED JOINTS; STEELS; NEUTRON DIFFRACTION; FINITE ELEMENT METHOD; CORRELATIONS; EXPERIMENTAL DATA

Citation Formats

Wang, X.L., Spooner, S., Hubbard, C.R., Taljat, B., and Feng, Z. Characterization of welding residual stresses with neutron diffraction. United States: N. p., 1998. Web. doi:10.2172/672109.
Wang, X.L., Spooner, S., Hubbard, C.R., Taljat, B., & Feng, Z. Characterization of welding residual stresses with neutron diffraction. United States. doi:10.2172/672109.
Wang, X.L., Spooner, S., Hubbard, C.R., Taljat, B., and Feng, Z. Sun . "Characterization of welding residual stresses with neutron diffraction". United States. doi:10.2172/672109. https://www.osti.gov/servlets/purl/672109.
@article{osti_672109,
title = {Characterization of welding residual stresses with neutron diffraction},
author = {Wang, X.L. and Spooner, S. and Hubbard, C.R. and Taljat, B. and Feng, Z.},
abstractNote = {Welding residual stresses are a key concern in the fabrication and use of structural components containing welds. Residual stresses in welds are caused by non-uniform expansion and shrinkage of differently heated zones during the thermal transient of a weld pass. In some alloys, solid state phase transformations occurring during the welding transient contribute additional residual stresses. Manufacturing problems arising from welding residual stresses include cracking and dimensional distortion. During use, tensile stresses in the welded zone limit the fatigue resistance of the component under cyclic loading. In an aggressive environment, tensile welding residual stresses also create a necessary condition for stress-corrosion cracking to take place.},
doi = {10.2172/672109},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1998},
month = {Sun Mar 01 00:00:00 EST 1998}
}

Technical Report:

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  • In order to assure that welded joints will perform acceptably, it is important to know the residual stress state in, and in the vicinity of the weld. In this report, residual stresses in electron beam welded specimens are characterized. They were measured using hole drilling and XRD. Residual stress data available in published electron beam weld studies were reviewed to supplement the collected measured data. Although there is considerable variability, trends can be established which should be considered by designers and manufacturers for structures to be fabricated by electron beam welding.
  • Numerical models have been extensively developed for predicting the thermomechanical behavior of ceramic-metal joints containing graded interlayers. The goal of such modeling is to be able to design optimum interlayer microstructural characteristics required to meet the needs of specific application conditions, and to use this design information to guide component fabrication. The graded specimen examined in this research was fabricated by powder processing methods. Al{sub 2}O{sub 3}-Ni was selected as a model system. The residual stresses expected in the specimen were predicted by FEM calculations using an elastic-plastic model. Strain and stress distributions in the specimen were characterized experimentally usingmore » x-ray and neutron diffraction techniques. Preliminary neutron and x-ray diffraction measurements were not in very good agreement with FEM model predictions, particularly regarding the in-plane stresses along the axis of symmetry. These results suggest additional diffraction measurements on graded specimens having fewer interlayers should be carried out, and experimental verification of the constitutive assumptions used in the FEM model is needed.« less
  • Using the Double Axis system for Residual stress, Texture, and Single crystal analysis (DARTS) at NIST, neutron diffraction residual stress measurements were carried out in the head region of five pairs of transverse and oblique cut slices of railroad track, each having a thickness of 6.35 mm. The slices were taken from a 300 HB rail of CFI 136 RE size. All slices except one unworn reference piece had the same accumulated tonnage but were ground in different intervals. The measurements confirm the results previously found which indicated the existence of high sub-surface residual tensile stresses, while the regional closemore » to the wheel-rail contact line shows high residual compressive stresses.« less
  • Aluminum clad monolithic uranium 10 weight percent molybdenum (U-10Mo) fuel plates are being considered for conversion of several research and test nuclear reactors from high-enriched to low-enriched uranium fuel due to the inherently high density of fissile material. Comprehensive neutron diffraction measurements of the evolution of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state ofmore » the material prior to annealing and the duration and temperature of the annealing process. In general, the HIP procedure significantly reduces the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stresses in the clad fuel plate do not depend strongly on the final processing step of the bare foil prior to HIP bonding. Rather, the residual stresses are dominated by the thermal expansion mismatch of the constituent materials of the fuel plate.« less