Experimental And Numerical Simulation Study On Rheo-squeeze Casting Process Of A356 Aluminum Alloy

In this paper, experiment and numerical simulation were applied to studying on rheo-squeeze casting process of A356 aluminum alloy. Numerical Simulation was used to completing casting system and guiding die repairing, which provided a guarantee for further process study. Then the optimal parameters were obtained by orthogonal experiment, which was confirmed by experimental verification. The experimental workload was effectively reduced by this way. The main contents and results were as follows:In this paper, there were two different models simulated by the numerical simulation software. After comparing the metal flow and inner gas situation of the two models during the filling and solidification process, and analyzing the position and the reason of the porosity defects and shrinkage porosity in the original model, the optimal solution were worked out which was useful for removing defects. It was found that simulation is coinciding with experimental results after experimental verification. Numerical simulation provides guidance for mold modification, which can decrease difficulties in designing the mold and effectively improve the production efficiency.Under the conditions of the improving gating system, standard orthogonal test method was used in analyzing the three parameters of die preheating temperature, extrusion pressure, extrusion speed influence on the microstructure and mechanical properties of castings. Range analysis and variance analysis can get the primary and secondary factors order for each index, the optimal experiment scheme and the significant of factors. And experimental verification was carried out. The parameters were more influential on mechanical properties than microstructure. In term of microstructure, the mold temperature was the main factor for the microstructure, however, for mechanical properties, the factors of primary and secondary order were followed by squeeze ratio pressure, mold temperature and pressure of injection speed, and the best combination of process parameters is squeeze pressure in 50 MPa, mold temperature in 200 C, injection velocity in 0.5m/s. which was turned out to be the best parameters combination by experimental verification at last. Under optimal parameters conditions, the microstructure of A356 aluminum alloy was fine and globular with equivalent grain diameter of 70-80?m and the shape factor of about 0.62. Mechanical properties of casting after T6 heat treatment achieved to tensile strength of 328 MPa, yield strength of 257 MPa and elongation of 10.6%.