Continuous semi-solid casting process for aluminum alloy billets

Abstract

A new process for continuous semi-solid casting of billets of aluminum alloys was developed. Round aluminum alloy billets 75 mm and 150 mm in diameter are continuously cast in a semi-solid state by agitating the alloy in the agitating vessel with a mechanical screw and/or an electromagnetic stirrer. The solidification structure of the billets obtained by this process is a mixed structure of granular particles and a fin eutectic structure, except in a thin chill layer about 2 mm in thickness, which shows a dendrite structure. It was possible to use billets of AC4C alloy obtained by this process in the thixoforming process without surface conditioning.