Optimization strategies of steel strip continuous heat treatment based on feasible sets

Based on the heat transfer model, optimization strategies were proposed for the steady and transition operating modes during steel strip continuous heat treatment processes. Feasible sets for every steel group (classed by steel grade and size) can be obtained by a heuristic optimization strategy in the steady operating mode. Based on the relations of feasible sets of different steel groups, an optimization strategy for the transition operating mode was developed, which minimized the differences between the steel strip temperature and target temperature of heat treatment by the adjustment of operating parameters. A comparison between the control strategy used in steelmaking plants and the new developed shows that the optimization strategy based on feasible sets can fulfill the transition operating mode more rapidly and control the temperature of steel strips more accurately.