Transverse Thickness Profile Control of Electrical Steel in 6-high Cold Rolling Mills Based on the GA-PSO Hybrid Algorithm

Abstract

In order to meet the shape control requirements of “Dead flat” transverse thickness profile of electrical steel sheet in cold rolling process, the 3D finite element model (FEM) for roll stacks and strip of 6-high tandem cold rolling mills (TCMs) was built with the developed Edge Drop Control Work Rolls for Non-shifting (EDW-N). The efficiency curves of the work roll bending (WRB), the intermediate roll bending (IRB) and the intermediate roll shifting (IRS) in cold rolling process are obtained for transverse thickness profile control performance. The control strategy of multi-stand and multi-variable profile and flatness control actuators, i.e. WRB, IRB and IRS of Stands 1 ~ 5 in 6-high TCMs is proposed based on the GA-PSO hybrid algorithm with better optimization ability. The results show that the control strategy can fully exploit the shape control ability and achieve the high precision control for transverse thickness profile of 6-high TCMs. The industrial application on the production gives remarkable results that the rate of the measured strip crown less than 7µm increased from 38.58–67.74% for electrical steel sheet in the 1420 mm 6-high TCMs. The control strategy has applied to the production successfully.