The effect of tallow concentration on the cold rolling of steel strips

Steel strips were cold rolled, using an oil-in-water emulsion to lubricate to surfaces. The effect of the oil concentration on the rolling variables was examined. The roll forces, torques and the exit velocity, leading to the forward slip, were measured as functions of the reduction, the speed and the amount of tallow. The coefficient of friction was calculated using Hill’s empirical formula. Varying the tallow concentration affected the roll forces, the torques and the coefficient of friction at higher reductions, but only to a limited extent. The coefficient of friction decreased with increasing reductions. As suggested by the dynamic concentration theory, sufficient amount of the oil was available to enter the contact zone in all instances. The conjunction appeared to be starved of the lubricant at the exit at low reductions.