Study On The Die Casting Processing Of Aluminum Alloy Based On Numerical Simulation

In this paper the pressure-die-casting processing of aluminum alloy was simulated by commercial foundry software.The mould filling and solidification process of aluminum alloy die-casting in different cast temperature and shot velocity was investigated.Aiming at achieving the best casting process,this research gave emphasis on analysis the influence of cast temperature and shot velocity to the process of mould filling,temperature field of casting part during filling and solidification, shrinkage and porosity. The main conclusions are summaried as follows.(1)When the cast temperature is 650-710℃at the same shot velocity, it plays a major role on the mould filling and feeding.With increasing of the cast temperature, completing mould filling and reducing shrinkage and porosity, the higher temperature, the better mechanical and the result of the mould filling,and 710℃is the perfect temperature.When the cast temperature is 710-730℃,it plays a major role on coarsening grains,hydrogen evolution,surface oxidation, shrinkage and porosity which is produced by expansion and contraction.With increasing of the cast temperature,the surface of casting part is oxidized,the crystal grain become coarse and fir-tree crystal turns up,the hydrogen separates out forming gas cavity and it come into being shrinkage and porosity after shrink, mechanical properties and the result of the mould filling become worse.So it is obviously that the mechanical properties and the result of the mould filling is the best when the cast temperature is 710℃at the same shot velocity.(2)When the cast temperature is the same,there are some differences between the fast shot and the slow shot.Because of high pressure in fast shot,the mobility of melt enhance,model fill quickly and takes a short time,which helps mould filling of the casting part and renduces shrinkage and porosity, and therefore increases structural density. Because of low pressure in slow shot, the mobility of melt is poor, mould filling slowly and takes a long time,which go against mould filling of the casting part and shrinkage when solidifying, increase of shrinkage and porosity, reduction of structural density.Therefore in the same cast temperature,the mechanical properties and the result of the mould filling is better in fast shot than in slow shot.(3)In the process of the solidification, there is an order which is thin walled part, common part,cross gate,sprue.The first solidification part is easy to form a new nucleate since the cooling rate and condenser depression is great,so that it restrains the crystal grain coarsening and the appearance of dendrite.Crystal grain is uniform and refine.The thin-walled part will have the perfect mechanical property.The die casting experiment was performed according to the optimized processing. And then the simulation results compared with the date of the experiment which include the analysis the tensile test, hardness and the density and microstructure. There is a perfect match in the comparison which is complete improve the right of simulation in the die casting and direct the production process.