Optimal modeling and analysis of steelmaking and continuous casting production scheduling

The steelmaking-continuous casting process in modern large steel plant is constituted by several casts, heats, converters, refining furnaces, casters and multiple refining modes. Scheduling problems are solved in existing literatures by two-stage or multi-stage modeling and optimization strategies, but there is no article that investigates the reason why specific strategy is taken. In this paper, the hybrid optimal scheduling model between output variables including device variables (which device) as well as time variables (when to work) and constrains is established on the basis of analyzing intrinsic relationship between the optimized target, constraints and decision variables of scheduling process in a large steel plant of China. In addition, the root cause why the optimization issue cannot be done in one step is described in detail. At the same time, a deep investigate on the reason why two-stage or multi-stage optimization is utilized to solve the schedule problems in the production process that contains multi-converters, multi-refining furnaces and multi-casting machines is carried out, which renders a theory basis for other researchers.