Effect of carbide properties of roll materials on lubricity in cold sheet rolling of low-carbon steel

The prevention of friction pick-up, which often occurs under the condition of high reduction and/or high speed, is required to improve the productivit y in cold sheet rolling of low-carbon steel, Therefore, rolls made of high- chromium steels and high-speed steels with different carbide contents are t ested in order to evaluate the effect of various properties of the carbide component of the materials on the lubrication characteristics. Coefficients of friction for the reduction in thickness and the limit of the reduction of friction pick-up are measured using the sliding-rolling simulation testi ng machine developed by one of the authors. The experimental results show t hat carbides on the surface of the roll can stop the increase in friction p ick-up, and that keeping the carbide spacing small is effective in preventi ng friction pick-up. Because of the effectiveness of carbides, a high-chrom ium steel roll with controlled carbide morphology is manufactured and appli ed in a cold tandem mill. The results of the application show that the carb ide-controlled roll has an excellent antiseizure property and is effective in improving productivity. (C) 2001 Elsevier Science Ltd. All rights reserv ed.