Investigation of Thin Wall Casting Made of Semi-Solid A356 Using Back Extrusion and Die Cast

Semi- solid forming is a new technology in recent decades that has a number of advantages over conventional casting routes. As a result of these advantages, semi-solid processes are less limited in the part geometry, mainly concerning the wall thickness. According to many researches on aluminum alloys, the evaluation of flow and die filling properties of alloys as well as their resulting mechanical properties which are depended on various process parameters are being investigated up to now. Semi- solid forming processes contain three main steps: feedstock manufacturing, reheating and forming. Feedstock quality and reheating have strong effect on success of forming procedure. In order to understand and describe forming behavior in the semisolid state, two different tests have been studied in the same casting conditions. In this study, back extrusion and die casting processes were used to investigate the effect of section size and process on the mold filling. In the case of back extrusion process a cup shaped specimen and in the case of die casting process, a step die with different sections size were used. Microstructure of different sections of specimens were studied by optical microscopy to depict the effect of different variables on the quality of products.