Optimal Estimation of Electrode Gap During Vacuum ARC Remelting

WILLIAMSON, RODNEY L; BEAMAN, J J; HYSINGER, C L; MELGAARD, DAVID K

Title: Optimal Estimation of Electrode Gap During Vacuum ARC Remelting

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Abstract

Electrode gap is a very important parameter for the safe and successful control of vacuum arc remelting (VAR), a process used extensively throughout the specialty metals industry for the production of nickel base alloys and aerospace titanium alloys. Optimal estimation theory has been applied to the problem of estimating electrode gap and a filter has been developed based on a model of the gap dynamics. Taking into account the uncertainty in the process inputs and noise in the measured process variables, the filter provides corrected estimates of electrode gap that have error variances two-to-three orders of magnitude less than estimates based solely on measurements for the sample times of interest. This is demonstrated through simulations and confined by tests on the VAR furnace at Sandia National Laboratories. Furthermore, the estimates are inherently stable against common process disturbances that affect electrode gap measurement and melting rate. This is not only important for preventing (or minimizing) the formation of solidification defects during VAR of nickel base alloys, but of importance for high current processing of titanium alloys where loss of gap control can lead to a catastrophic, explosive failure of the process.

Authors:: WILLIAMSON, RODNEY L; BEAMAN, J J; HYSINGER, C L; MELGAARD, DAVID K

Publication Date:: Wed Jun 14 00:00:00 EDT 2000

Research Org.:: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Sponsoring Org.:: US Department of Energy (US)

OSTI Identifier:: 759874

Report Number(s):: SAND2000-1512J
TRN: AH200031%%123

DOE Contract Number:: AC04-94AL85000

Resource Type:: Journal Article

Journal Name:: Metallurgical and Materials Transactions B

Additional Journal Information:: Other Information: Submitted to Metallurgical and Materials Transactions B; PBD: 14 Jun 2000

Country of Publication:: United States

Language:: English

Subject:: 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 36 MATERIALS SCIENCE; ARC FURNACES; VACUUM FURNACES; ELECTRODES; METAL INDUSTRY; MELTING; NICKEL BASE ALLOYS; TITANIUM ALLOYS; PROCESS CONTROL; WIDTH

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                    WILLIAMSON, RODNEY L, BEAMAN, J J, HYSINGER, C L, and MELGAARD, DAVID K. Optimal Estimation of Electrode Gap During Vacuum ARC Remelting.  United States: N. p., 2000. 
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                    WILLIAMSON, RODNEY L, BEAMAN, J J, HYSINGER, C L, & MELGAARD, DAVID K. Optimal Estimation of Electrode Gap During Vacuum ARC Remelting.  United States.

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                    WILLIAMSON, RODNEY L, BEAMAN, J J, HYSINGER, C L, and MELGAARD, DAVID K. 2000.  
        "Optimal Estimation of Electrode Gap During Vacuum ARC Remelting".  United States.  https://www.osti.gov/servlets/purl/759874.

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@article{osti_759874,

  title        = {Optimal Estimation of Electrode Gap During Vacuum ARC Remelting},

  author       = {WILLIAMSON, RODNEY L and BEAMAN, J J and HYSINGER, C L and MELGAARD, DAVID K},

  abstractNote = {Electrode gap is a very important parameter for the safe and successful control of vacuum arc remelting (VAR), a process used extensively throughout the specialty metals industry for the production of nickel base alloys and aerospace titanium alloys. Optimal estimation theory has been applied to the problem of estimating electrode gap and a filter has been developed based on a model of the gap dynamics. Taking into account the uncertainty in the process inputs and noise in the measured process variables, the filter provides corrected estimates of electrode gap that have error variances two-to-three orders of magnitude less than estimates based solely on measurements for the sample times of interest. This is demonstrated through simulations and confined by tests on the VAR furnace at Sandia National Laboratories. Furthermore, the estimates are inherently stable against common process disturbances that affect electrode gap measurement and melting rate. This is not only important for preventing (or minimizing) the formation of solidification defects during VAR of nickel base alloys, but of importance for high current processing of titanium alloys where loss of gap control can lead to a catastrophic, explosive failure of the process.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/759874},
  journal      = {Metallurgical and Materials Transactions B},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Wed Jun 14 00:00:00 EDT 2000},

  month        = {Wed Jun 14 00:00:00 EDT 2000}

}

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