Lubrication characteristics of physical vapor deposition Tin-coated roll for high productivity in cold rolling of low-carbon steel sheet

The prevention of friction pickup, which often occurs under the condition of high rolling reduction and/or high rolling speed, is required to improve productivity in the cold sheet rolling of low-carbon steel. Therefore, the lubrication characteristics of a TiN-coated steel roll treated by the physical vapor deposition (PVD) process are evaluated quantitatively and compared with those of a conventional steel roll. Coefficients of friction for the reduction in thickness and the limit of the reduction of friction pickup are measured using a sliding–rolling simulation testing machine. The experimental results show that the limit of the reduction of the TiN-coated roll is much higher than that of the conventional roll. Moreover, the maximum rolling speed of the TiN-coated roll used in an actual mill is calculated. The results show that the maximum rolling speed of the TiN-coated roll will be two times faster than that of the conventional roll.