Analysis of Chatter in Tandem Rolling Mills based on Tresca Model

During the cold rolling of thin strips, undesired mechanical vibration, generally referred to as chatter, is often observed. It causes unacceptable gauge variation to the strip and its surface finish. It has also been found that as the rolling speed is increased, the system goes to instability. As the need for lowcost and high-quality products increases, prevention of chatter phenomenon becomes an important task in the rolling industry. To overcome this phenomenon a deep understanding of the cause of chatter is required. In this research, a chatter model in tandem rolling mills based on the friction factor or Tresca model is proposed. 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.