Twin Roll Casting and Formability of Al-25%Si Alloy Strip

Abstract

This study was aimed at investigating of Twin roll casting and formability of Al-25%Si alloy strip. Near net shape forming is able to produce that the initial production is very close to the final shape. Near net shape is applied a variety of materials. Twin roll casting process is one of near net shape forming. Hypereutectic Al-Si alloy has some useful advantage low thermal expansion, better thermal conductivity and wear registrant. Recently, the plate of hypereutectic Al-Si alloy which thickness is thinner than 1mm is demanded. The hypereutectic Al-Si alloy is hard and brittle. Therefore, only the many times of hot rolling were useful process to make thin plate. In the present study, the roll casting of Al-25%Si strip was tried by a vertical type high speed twin roll caster from the point of energy saving. The twin roll size of the roll was φ300×W100. Roll-load was set low enough to prevent the sticking of the strip. Casting material was Al-25%Si and Al-25%Si+4%Mg. The roll velocity was 20 m/min. As cast strip of Al-25%Si was 1.6 mm thickness, and Al-25%Si+4%Mg was 2.0 mm thickness. Primary crystal size of as cast Al-25%Si strip was 40-100 μm, as cast Al-25%Si+4%Mg strip was 40 μm. It was able to produce that as rolled strip of 1mm thickness at 1 pass. Primary crystal size of as rolled Al-25%Si strip was 15-40 μm, and as rolled Al-25%Si+4Mg was 15-20 μm.