Studi Pembuatan Struktur Globular Dengan Metode Sima Untuk Proses Semisolid Forming

Abstract

Abstract : The aim of this research is to study the making of globular microstructure by the SIMA (strain-induced melt activation) method for semisolid forming materials. Semisolid forming is a metal working process done in the mixture of liquid and solid phase. SIMA is a method used in semisolid forming process to obtain globular structured metal by deforming the dendritic - structured metal in the room temperature and then heat it above the solidus temperature. In this research, the variations used are rolling percentage of specimen and the type of mold. Material used in this research is from car velg, which is Al-6%Si hypoeutectic Al alloy. The globular microstructure is obtained by heating the Al-Si specimens which is plastically deformated oin cold rolling. The heating temperature is 590 0C (between TS and TL) then quenched in the water. To measure the diameter and the roundness of the grain, the image analyst software is used. The result shows that the globular microstructure begins to appear when the rolling strain reach 6%, for the casting from both metal and sand mould. The larger the plastic deformation given to the specimen, the higher the shape factor and the finer the grain obtained.

Keywords : SIMA, Globular, Semisolid Forming