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Title: Advancing alloy 718 vacuum arc remelting technology through developing model-based controls.

Conference ·
OSTI ID:968940
 [1];  [2];  [3];
  1. Special Metals Corporation, Huntington, WV
  2. University of Texas, Austin, TX
  3. Zan Tek Enterprises, Sandia Park, NM

The Specialty Metals Processing Consortium (SMPC) was established in 1990 with the goal of advancing the technology of melting and remelting nickel and titanium alloys. In recent years, the SMPC technical program has focused on developing technology to improve control over the final ingot remelting and solidification processes to alleviate conditions that lead to the formation of inclusions and positive and negative segregation. A primary objective is the development of advanced monitoring and control techniques for application to vacuum arc remelting (VAR), with special emphasis on VAR of Alloy 718. This has lead to the development of an accurate, low order electrode melting model for this alloy as well as an advanced process estimator that provides real-time estimates of important process variables such as electrode temperature distribution, instantaneous melt rate, process efficiency, fill ratio, and voltage bias. This, in turn, has enabled the development and industrial application of advanced VAR process monitoring and control systems. The technology is based on the simple idea that the set of variables describing the state of the process must be self-consistent as required by the dynamic process model. The output of the process estimator comprises the statistically optimal estimate of this self-consistent set. Process upsets such as those associated with glows and cracked electrodes are easily identified using estimator based methods.

Research Organization:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC04-94AL85000
OSTI ID:
968940
Report Number(s):
SAND2005-4022C; TRN: US201001%%209
Resource Relation:
Conference: Proposed for presentation at the International Symposium on Superalloys 718, 625m 706 and Derivatives held October 2-5, 2005 in Pittsburgh, PA.
Country of Publication:
United States
Language:
English