STUDY ON A HIGH-SPEED TWIN ROLL CASTER FOR ALUMINUM ALLOYS

摘要

A vertical type twin roll caster equipped with a nozzle and side dam plates, that can cast aluminum alloy strip at the speeds higher than 90 m/min, was designed and assembled. Copper rolls were used and lubricant was not sprayed on the rolls, in order to increase the cooling speed of the strip. Separating force was very small and the strip was not hot rolled. Therefore, the strip did not stick to the roll without use of lubricant. Contact length between the roll and melt could be constant by the use of nozzle, when meniscus was bounced. Its was shown that this caster can cast the thin strips of A1050, A3003, A5182, A6063, AC4C (A356) and Al-20%Si at speeds from 90m/min to 150m/min. This caster was able to cast the aluminum alloys like A5182 and Al-20%Si, that freezing zone is very wide, at high speed. Microstructure of the strip was very fine, and not columnar structure but equiaxed structure. Thickness of the strip was within the range from 1.2mm to 2mm. As cast strips could be cold rolled up to 0.5mm without annealing. Rolling of 20% reduction was enough to make surface of the strip flat and thickness distribution uniform. Mechanical properties of the strips were investigated.