Effect of work roll shifting control on edge drop for 6-hi tandem cold mills based on finite element method model

Abstract

Controlling the profile and edge drop in the cold rolling process is crucial especially in applications involving silicon steel. In non-oriented silicon steel production, the work rolls shifting control is widely applied in 6-high tandem cold mills and the differences of the control characters of different stands have been gradually recognized. However, because of the lack of research on shifting control effect of separate stands and their influence between each other, controlling the edge drop by cooperatively shifting the work rolls of multiple stands is still impossible, so the mills’ capability is not utilized efficiently. In this study, we develop a finite element method (FEM) model to investigate this issue. Based on the results of the FEM model, we conclude that work roll shifting of different stands leads to the independent control of edge drop, obtain the shifting control effect of different stands to their exit, and the attenuation effects by the following stands. Besides, we deduce that the approach to calculating the edge drop control characteristics should be modified to summation equation of the attenuation effects. The results of an experiment involving 6-high tandem cold mills are in agreement with the results of calculation with the FEM model and we demonstrate the high precision of the FEM model and the reliability of the subsequent analysis. Based on the edge drop control characters established, the control model and the cooperation strategy were designed and applied to the practical production, and significant improvements of edge drop and transverse thickness deviation were obtained.