A multi-stand work roll bending and shifting approach for profile contour and flatness control of electrical steel in multi-width schedule-free rolling using NSGA-II algorithm

Abstract

To overcome the severe uneven work roll wear and uneven deformation of the wide-width electrical steel in the SFR (Schedule-Free Rolling) is an effective way to organize production flexibly and maximize production efficiency in hot rolling. In order to meet the increasingly stringent requirements of PCFC (Profile Contour and Flatness Control) of multi-width electrical steel in hot rolling, the collaborative control strategy of multi-stand work roll bending and shifting for profile and flatness of electrical steel in multi-width SFR was developed using NSGA-II approach. The work roll wear prediction model, thermal crown model, and strip crown model were established based on on-site measured data. Combining the work roll wear characteristics with principle, the mathematical model for work roll shifting considering multi-width was established. The main parameters of the multi-width work roll shifting strategy are obtained using the multi-objective NSGA-II algorithm. On this basis, a multi-stand collaborative control strategy, including rolling contour, short stroke roll shifting, and work roll bending, in the downstream stands during multi-width SFR was proposed. The industrial application of the developed control strategy shows that can prominently enhance the PCFC capability of electrical steel, which the uneven wear contour can be reduced.