Study On The Process,Microstructure And Properties Of Aluminum Alloy Die Castings With Complex Structure

Aluminum alloy has become the most widely used non-ferrous metal material in die casting industry,because of its comprehensive mechanical properties and processing performance.Reassure casting technology is widely applied owing to its advantage such as high production efficiency,high precision and good product quality.But the traditional die casting method usually depends on the empirical formula and the constant test modification.Because the die casting process is influenced by many factors,the production cycle is long and the quality of the product is poor.Based on the shortcomings of traditional methods,with the development of computer technology,numerical simulation technology has been paid more and more attention.This paper takes the case of automobile air conditioner compressor as the Research object,and its material is Al-Si alloy.The casting simulation software Procast and the mechanical analysis software Ansys workbench are used in this paper.The orthogonal experimental design and structural statics analysis of shell production process are carried out based on design principle and experience of casting process structure and numerical analysis theory.The distribution of internal defects in castings is predicted.And then optimize the production process and structure of the shell.Finally determine the reasonable production process plan.The effects of different alloy elements on the mechanical properties of the Al-Si alloy were studied on the basis of the addition of different alloy elements.The main contents of this paper are as follows:1.First,the 3D modeling of shell is made by using Croe 3D drawing software,and the gating system of shell production is designed according to the requirements of shell production and design experience.The GeoMESH software is used to make a grid analysis of the three-dimensional shell of the shell,and then the Reasonable pouring system is determined by the simulation analysis.2.Orthogonal test.In a variety of influencing factors,the three main factors that affect the pouring temperature,the injection velocity and the die temperature are selected.The L9(34)orthogonal test table was designed.According to the thermophysical parameters of shell materials,the horizontal values of each factor were determined respectively.Orthogonal simulation is carried out and the flow field and temperature field of metal liquid in the process of filling and solidification are analyzed and the distribution of defects is predicted.The optimum selection process parameters are 670 C pouring temperature,4 m/s press velocity and 240 C die temperature.3.Structural statics analysis.The size of the shell structure is optimized and simulated.On the premise of guaranteeing the use requirements,reducing the thickness of the shell wall to reduce the heat joint and improving the quality of the castings.4.Mechanical properties analysis.Based on the Al-Si alloy,the shell was produced by adding different alloying elements,and the mechanical properties of the shell were studied.It is found that the quality of the shell with Cu and rare earth La elements is the best.The tensile strength,elongation and Brinell hardness of the sample are increased by 51.5%,63.9% and 61.2%,respectively,compared with the base alloys.