Research On Modeling And Optimization Algorithms For DHCR Integrated Scheduling Problem

A high rate of direct-hot-charge in steel production has significant benefits in many respects, such as cost reduction, improved productivity, stock reduction, shortened lead times, reduced slab handling (transportation) costs and environment benefits. However, scheduling a direct-hot-charge rolling sequence for the hot strip mill is a daunting task because direct-hot-charge scheduling requires temporal synchronization and sequence consistency between CC (continuous caster) and HSM (hot strip mill) production schedules. The slabs assigned to certain coil (order) must be cast before entering to the next stage, i.e., HSM, and the slab should still be hot enough when being charged into the reheating furnace. Furthermore, slabs must be rolled in the same sequence as that in which they were cast. Thus the integration of CC and HSM scheduling is vital to increase hot charge ratio in steel production for reducing energy and inventory costs, increasing throughputs and fulfilling customer orders on-time, etc.In this dissertation, we analyze detailed scheduling requirements of...