Study On Die Casting Processing And Performance Of Semi-solid Alumimum Alloy Prepared By Sectional Type Slope Plank Method

Use the self-developed section type tilt board gating system device, with DCC500B type cold room to A356aluminum alloy die casting machines semi-solid rheo-diecasting decreased the process of the system. The main research A356aluminum alloy die casting semisolid liquid and the process parameters optimization, liquid die casting and semi-solid die casting before and after heat treatment microstructure and mechanical performance analysis, and discusses the different process parameters on the die casting microstructure and mechanical properties and the analysis of the influence of the apparent quality. The experimental results show that:To block type tilt plate method for semi-solid aluminum alloy A356size the best technical parameters for:pouring temperature:670℃, material:steel/graphite, Angle:30°/50°, plate long:250/150mm. Sure A356liquid die casting and semi-solid rheo-diecasting decreased the best technical parameters are:the A356liquid die casting the best technical parameters for:pouring temperature:630℃, mould preheating temperature:120～150℃, two quick shot speed:0.8m/s, injection pressure:30MPa, shot than the:78MPa. A356semi-solid casting the best technical parameters for:pouring temperature:670℃, mould preheating temperature:150-180℃, two quick shot speed:1.16m/s, injection pressure:30MPa, shot than the:78MPa.Cryogenic liquid semi-solid casting die casting and organization are made by the big size of the primary alpha Al, tiny second primary α2-Al and needle of Al-Si eutectic organization of three parts. Liquid of low temperature and the organization of the semi-solid casting, compared the tissue of the die casting liquid more porosity, semi-solid casting primary alpha Al phase more rounded. Semi-solid die casting surface and the same sample of tissue were different, and surface organization primary phase alpha Al have mutual fusion, the trend of the connection, and in surface organization, there are a lot of tiny second primary α2-Al phase, belongs to the obvious quench organization.Compared with liquid die casting, semi-solid die casting in the mechanical properties are improved, the range of the increased is:tensile strength increased by31.6%, the elongation increased by68%. And the semi-solid die casting after heat treatment by T6, mechanical properties have further improved. Tensile strength from the original229MPa increased to249MPa, up by8.7%; Elongation rate from8.3%increase to19%, increased2.3times.The tensile fracture morphology analysis of the liquid, semi-solid die casting tensile fracture form as disintegrate fracture, semi-solid die casting the tensile fracture after heat treatment in the form of the cell (wear crystal) fracture prospective disintegrate fracture.