Development of asymmetric cold rolling technology of high-strength steel grades in order to exclude intermediate annealing operations

Abstract

Abstract. The technological process of manufacturing cold-rolled strip with a thickness of 0.5-1.5 mm from high-strength steel grades on cold rolling mills can consist of 2 or even 3 operating cycles "cold rolling - intermediate annealing". This is due to a significant hardening of such steels during cold rolling and, as a result, limitations on the maximum allowable rolling forces. Each additional operating cycle "cold rolling - intermediate annealing" significantly increases production costs and reduces the productivity of the technological process. One of the promising ways to reduce the rolling force is the asymmetric rolling. Rolling at different circumferential speeds of work rolls driven by two independent motors is the most suitable way to implement asymmetric rolling technology in industry. The paper presents data on the operation of the main electric drives of a five-stand industrial mill during symmetric and asymmetric cold rolling. Speed ratio of the work rolls was varied in the range from 1.0 to 1.5. Electrical and power parameters were calculated, measured and compared. Based on numerical simulation, laboratory and industry experiments it was shown that the asymmetric cold rolling makes it possible to reduce the rolling forces, increase the thickness reduction per pass and, as a result, obtain a thinner strip without the use of intermediate annealing.