Finite Element Simulation and Optimization for Low Pressure Casting of Automobile Aluminum Alloy Wheel

The defect distributions and solidification fields of A356 aluminum alloy wheels by the low pressure casting process were simulated by the casting simulation software MAGMA. Based on the simulation results, the process was optimized. The A356 aluminum alloy wheels were manufactured by the preliminary and the optimum low pressure casting process respectively and the mechanical properties were tested. The defects in the wheels were also observed and compared with the simulation results. The results show that when using the preliminary process (at the pouring temperature of 730 ℃ and air cooling every parts), the shrinkage porosity was produced at the inner wheel flange, the spoke and wheel rim junction and the wheel rim, and the solidification time was relatively long. After optimizing the preliminary process by lowering the pouring temperature to 700 ℃, increasing the heat exchange coefficients at the side-core, top-core, wheel rim and bottom-core and water cooling the spoke and wheel center, the shrinkage porosity in the wheel was eliminated and the separate parts of the wheel were solidified completely. The mechanical properties of the wheel casted by the optimized process were higher than those by the preliminary process and the defects such as shrinkage porosity and slag were fewer. The accuracy of the finite element simulation for the defect prediction in the low pressure casting wheel was verified by the experimental results.