Finite element modelling of strip curvature during hot rolling

Abstract

Finite element techniques have been used to decouple some of the major causes of strip curvature in the roughing stages of a hot strip mill. A plane strain elastic-plastic model is used to predict the direction and severity of strip curvature caused by asymmetrical factors at each pass of the rougher. Asymmetrical factors considered include work roll speed mismatch, temperature differentials across the thickness of the workpiece, pass height, and frictional differences between upper and lower work rolls. A full factorial experiment was then designed and performed, using finite element predictions, to identify which asymmetrical factors are most influential to strip curvature, and to determine the interactions, if any, between factors. The results show that three of the asymmetrical factors are significant to strip curvature, but their influence depends on the rolling pass. This study will allow the rolling operator to identify which asymmetrical factor may be causing strip curvature and, thus, provide a suitable course of action.