Strip Casting of Al-25%Si-4%Mg Using Unequal Diameter Twin Roll Caster Equipped with Steel Rolls

Abstract

Strip casting of Al–25%Si was tested using an unequal-diameter twin-roll caster equipped with steel rolls. To increase the cooling ability, the shell thickness was decreased to 6 mm. The solidification length was 180 mm to solidify Al–25%Si, which has large latent heat. 4% Mg was added to Al–25%Si to prevent the strip sticking to the roll without using parting material. A grooved roll was adopted for the upper roll to prevent solidification shrinkage and strip cracking during rolling. Al–25%Si–4%Mg strip could be cast at a roll speed of 10 m/min by these enhancements. The as-cast strip could be hot rolled down to 1 mm. A cross section of the strip was investigated using optical microscopy, and the primary Si and eutectic Si were found to be very fine.