Development of Three-Dimensional Strip Profile Model for Thin-Foil Cold Rolling

Accurately predicting the strip profile after thin-foil cold rolling is very difficult because of the thinness of the strip. In this study, a three-dimensional (3D) strip profile model was developed to improve the accuracy of a rolled thin-foil profile. The distribution of the contact pressure between rolls (i.e., the work, intermediate, and backup rolls) and the rolling pressure between the strip and work roll were calculated by using the geometric structure of a 6-high mill and boundary conditions imposed in the width direction by a numerical method. The rolling pressure distribution in the rolling direction was determined by Fleck's model of thin-foil rolling. The 3D rolled-strip profile was predicted by using the pressures in the width and rolling directions. In order to investigate the effect of the rolling speed and rise in strip temperature on the lubrication, the friction coefficient was estimated through an analytical method and experiments to test the viscosity and friction. The resulting 3D strip profile was verified by a thin-foil cold rolling test and was compared with the profile obtained using the proposed 3D model and finite element simulation.