Analysis of Chatter in Tandem Rolling Mills based on Coulomb Model

Cold rolling is the most vital process in manufacturing flat sheet products. During the cold rolling of thin metal sheets, undesired mechanical vibrations, generally referred to as chatter, are often generated. It usually lowers the surface finish of the sheet and in some cases causes gauge variation. It may also cause severe damage to the rolling mill and strip rupture under extreme conditions. In this research, a chatter model in tandem rolling mills is proposed based on the friction coefficient model or the Coulomb model. To study chatter in rolling, it is necessary to set up models for the rolling process as well as the mill stand. The model relaxes certain assumptions, by considering the influence of the material strain-hardening effect and the elastic deformation of the work roll. The results of the simulation are verified by comparing to experimental data obtained from a full scale industrial mill. The main chattering characteristic, i.e., the critical rolling speed, obtained from the simulation program has been found to be in good agreement with that of the experimental measurements.