Research on roll profile thermal-force driving characteristics and joint control strategy in the multi-zone roll profile electromagnetic control technology

Abstract

Roll profile electromagnetic control technology (RPECT) is a new roll gap shape control technology that can flexibly control the roll profile to meet the flatness control requirements of cold rolling mill. As basic control elements, electromagnetic sticks (ES) can drive the local zone bulging of electromagnetic control roll (ECR) to generate thermal-force contribution roll profiles. Due to the high order profile defects in the thin-gauge strip rolling process, the requirement of roll gap shape control in cold rolling mills is usually characterized by multi-zone and micro-scale. Therefore, a multi-zone roll profile electromagnetic control technology is proposed in this paper, which includes a multi-zone joint control strategy and a parameter preset method for basic control elements targeting roll profile. To conduct the parameterized impact analysis of stick distance and multi-stick control modes, a multi-zone joint control simulation model is established. Through the simulation analysis, the results show that it is feasible to use multiple basic control elements to adjust the multi-zone roll profile in the mechanism of action, and the total roll profile curve can be equivalent to the superposition of the individual bulging curve of different basic control elements with different space-time parameters. Meanwhile, the reasonable distance setting can effectively avoid the instability of thermal contribution roll profile control caused by too small distance between sticks and too strong thermal bulging driving. For the double-stick control mode or the three-stick control mode, using different temperature control method can assist ECR to realize the roll profile control goal that the low-order roll profile of the basic control element is superimposed to construct the high-order roll profile curve. According to strip flatness electromagnetic control experiment, the multi-zone joint control of RPECT can adjust the flatness defects above 100 IU to flat state, and can flexibly regulate local shape problems and control local buckling.