6111 Aluminium alloy strip casting using an unequal diameter twin roll caster

An unequal diameter twin roll caster with a long solidification length was devised to cast aluminium alloy strip with a thickness of about 5 mm at speed higher than 20 m/min. The characteristics of the unequal diameter twin roll caster with a long solidification length are as follows. The diameter of the lower roll is four times larger than that of the upper roll. The solidification length is up to 300 mm. The casting speed is up to 60 m/min. Using the unequal diameter twin roll caster, a 4.5 mm thickness of 6111 strip could be cast at a speed of 30 m/min. Low superheat casting and semisolid casting was adopted to the unequal diameter twin roll caster with a long solidification length. The macrostructure of the as-cast strip was equiaxed and spherical, not columnar. The mechanical properties of the strip rolled from roll-cast strip were almost as same as that of the strip made from cast ingot.