On using Kalman Filter for Estimation of Unmeasurable Variables in Steel Mill Soaking Pit Control

In steel production, the main goal of the soaking pit operation is to equalize the temperature throughout the steel ingot masses at some prespecified level. Poor knowledge about the temperature distribution within the ingots results either in the underheating of ingots and an inability to roll them by the rolling mill, or in the overheating of ingots and a waste of energy. Unfortunately, no practical ways of direct measurement of the extermal and internal ingot temperatures (at least, for typical U.S. soaking pits) exist today. Thus, some estimation procedure is needed to do the on-line evaluation of the ingot temperatures. This paper describes one approach to the problem and some encouraging results that came out of its realization. A Kalman filter was used for the on-line ingot temperature estimation.