Optimization of reduction schedule in a tandem cold rolling mill considering the material properties of the strip

The material properties of the strip play a vital role in the power consumption and the damage evolution in a tandem cold rolling mill. Therefore, the strip tearing or power consumption level of importance is not the same for different materials. Besides, various reduction schedules can be proposed for the specified total reduction and initial strip thickness in the tandem cold rolling process. An important goal that the reduction patterns should be met is to minimize power consumption and damage evolution simultaneously. Firstly, the level of importance of saving energy and strip tearing should be calculated for each material to find a reduction schedule. For this purpose, the Bao-Wierzbicki (BW) ductile damage criterion is selected and calibrated by the hybrid experimental–numerical method for five widely used carbon steel alloys. Then, the fracture loci of selected materials are constructed and implemented into an explicit finite element code. A five-stand tandem rolling mill is simulated numerically in which the flattening phenomenon of the rollers is considered. By comparing the simulation results, an indicator is introduced for the comparison of steel grades in terms of the rolling power consumption and damage evolution in a specified rolling program. Afterward, the Pareto optimality is undertaken to optimize the power-damage objective function. This paper presents a new method for determining the importance of damage evolution and power consumption based on material properties. This method significantly reduces energy consumption and the probability of strip tearing simultaneously in a tandem cold rolling mill.