Yoshiro Seki

Optimal multivariable looper control for hot strip finishing mill

An optimal multivariable looper control system based on optimal-regular theory has been developed for hot-strip finishing mills. Loopers of the mill are installed between stands and are in many cases driven by motors. The goal of looper control is to maintain product quality at a high level by stabilizing the rolling operation. Stability is achieved by keeping the looper angle and tension applied to the strip at given reference values. Control-system features are outlined. It is shown that the control system can maintain a relatively constant strip tension without operator intervention in the presence of rapid change of hydraulic screw down such as automatic gauge control operation. Data obtained at a commercial plant demonstrates that optimal multivariable looper control is more effective than conventional control or noninteractive control.<<ETX>>

Development of a simulator to calculate an optimal slab heating pattern for reheat furnaces

To improve energy consumption and to meet quality requirements for the slab heating process of reheat furnaces in hot strip mills, a new optimal slab heat pattern calculation simulator has been developed. The simulator consists of the following functions; (1) two-dimensional (slab thickness direction and slab length direction) slab temperature calculation function, which is capable of calculating skidmarks along the length of a slab, (2) furnace heat balance calculation function, (3) optimizing calculation function of slab heat pattern using a linear programming method. The simulator developed has been installed into a furnace computer control system for an actual plant. This paper describes the functions of the simulator and simulation results using the simulator.