Optimization of lubrication system for flatness control process in cold tandem rolling
BAI Zhen-hua1,2, WANG Nan1, CUI Xi-ying1, ZHANG Ya-zhen1
1. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, Hebei, China; 2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China
Abstract：In the process of strip speed rise and fall of tandem cold rolling mill, the rolling speed will fluctuate frequently and greatly, and the friction coefficient in the rolling deformation zone will fluctuate greatly, causing the rolling pressure to fluctuate back and forth, resulting in the problem that the shape in the speed rise and fall stage is significantly worse than that in the stable stage. The optimization of process system is very effective for the shape problem caused by friction coefficient. Therefore, firstly, this paper analyzes the shape change process of strip steel in the process of speed increase and decrease under different emulsion concentration, initial temperature and flow rate. In view of the shape defects in the speed up and down stage, the strip steel is divided into several strip elements along the transverse and longitudinal directions by using the piecewise discrete method, the transverse and longitudinal objective functions of the shape in the speed up and down process are proposed, and then the dynamic change objective function of the shape in the speed up and down process is constructed to realize the comprehensive control of the shape fluctuation in the transverse and longitudinal directions in the rolling process. Since the emulsion concentration and initial temperature cannot be changed in the rolling process, combined with the shape objective function, the optimal setting function of emulsion concentration and initial temperature is proposed under the constraints that the strip does not slip and heat scratch and the rolling force of each stand does not exceed the limited rolling force; The emulsion flow optimization can effectively control the frequently changing local wave shape defects. Therefore, the emulsion flow generally changes nonlinearly with the rolling speed. Taking the minimum fluctuation of outlet plate shape as the control function, and taking no slip and thermal scratch and the total amount of emulsion in each frame as the constraint conditions, the emulsion flow following speed optimization function is proposed. Finally, the optimization model is applied to the tandem cold rolling mill of a domestic steel plant. According to the rolling force distribution before and after optimization and the cloud diagram of strip shape, it can be seen that the field application effect is good.
白振华, 王楠, 崔熙颖, 张亚震. 冷连轧升降速过程板形控制工艺润滑制度优化[J]. 钢铁, 2021, 56(12): 96-102.
BAI Zhen-hua, WANG Nan, CUI Xi-ying, ZHANG Ya-zhen. Optimization of lubrication system for flatness control process in cold tandem rolling[J]. Iron and Steel, 2021, 56(12): 96-102.
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2021, Vol. 56 
