An overview of SMPC research programs to improve remelt ingot quality

Research conducted by the Specialty Metals Processing Consortium has focused on developing tools to improve the quality of specialty alloy ingots produced by vacuum arc remelting (VAR) and electroslag remelting (ESR). Especially during the last ten years, the program has focused on developing model-based process monitors and controllers. These tools employ predictive, dynamic, low-order electrode melting and ingot solidification models to estimate important process variables. Process monitors log these estimated variables (some of which are not subject to measurement) to computer files and use them to evaluate the health of the processes. Monitors are capable of detecting and flagging various process upsets and sensor failures. Process controllers use the model-based variable estimates for feedback. Improved melt rate controllers have been developed using this method. Additionally, VAR pool power and pool depth controllers have also been demonstrated. Laboratory and industrial trials have shown the robustness and accuracy of these tools. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.