Further experimental data on rolling tin-plated strip in the S-mill

Abstract

An experimental study was made of the S-mill rolling process, in which rolls reduce thin tinplate by novel means without recourse to the conventional rigid roll gap. In the S-mill process, strip is drawn through rotatable dies; consequently, the process is limited by the front tension the strip will carry. Experimental results indicated that optimum operational conditions existed when the mill rolls were set to the minimum possible alpha-angle; this is the critical angle of alignment between the centres of the work-rolls and the last back-up roll. Moreover, when the alpha-angle was at a minimum, the work done by the torque was least and that by tension difference was the greatest. The maximum strip reduction obtained in a single pass was 54.2%. Experiments were also conducted in which the larger work-roll was driven; the results obtained from these experiments showed that when the work-roll was driven with positive torque, little difference was detected in strip tensions, although the rollseparating forces were, in general, reduced. However, when the larger work-roll acted as a brake, substantial reductions were found to occur in both the front and back strip tensions.