Structure And Process Optimization Of High Pressure Die-Casting For Aluminum Alloy Camshaft Cover Based On ProCAST

With the continuous improvement of China's industrialization and people's living standards,China's total car ownership is at a high level,and the problems of energy consumption and exhaust emissions caused by cars need to be solved.Aluminum alloy die casting,a lightweight technology of automobile,can realize the development of low-carbon model of automobile industry.In order to explore the advanced design route of large and medium-sized die-casting die design,this paper studies the die-casting die design and process optimization of aluminum alloy camshaft cover based on numerical simulation technology,p-Q2 diagram technology and response surface experimental design.The specific research contents are as follows:Firstly,the design of gating system and overflow system and the selection of die casting machine are completed by traditional theoretical design.When the cross-sectional area of ingate is 467.6mm2 based on p-Q2 diagram technology,the matching performance between the designed die and the selected die casting machine is optimal.Secondly,in order to verify the rationality of the original gating system designed in theory,ProCAST is used for numerical simulation.According to the simulation results,the gating system is improved,and finally the improved scheme of pouring the left side of the original scheme into the merged five runners is determined,which improves the flow pattern of molten metal and the feeding condition of the isolated liquid phase zone during solidification,and reduces the shrinkage cavity?volume by 73.8%.Then,the die-casting cycle of the die without water cooling is simulated,and the initial temperature field distribution of the die after temperature stabilization is obtained.Two cooling system schemes are designed according to the temperature field distribution.Finally,according to the heat balance and temperature distribution of the two schemes,the cooling channel scheme is determined.Subsequently,the response surface experiment was designed to optimize the die casting process parameters,and the response surface of casting temperature,mold preheating temperature,injection speed,shrinkage cavity volume and solidification time was established As far as solidification time is concerned,the influence degree of die casting process parameters from big to small is:die preheating temperature,pouring temperature and injection speed,and the optimal process level is obtained:pouring temperature 610?;The preheating temperature of mold is 160?;The ejection speed is 1.56m/s.For the shrinkage cavity volume,the influence degree of die casting process parameters from large to small is:die preheating temperature,pouring temperature and injection speed,and the optimal process level is obtained:pouring temperature 610?;The preheating temperature of mold is 200?.The ejection speed is 1.30m/s.By integrating casting quality and solidification time,the optimal parameters of the final die casting process are as follows:pouring temperature 610?;The preheating temperature of mold is 200?.The ejection speed is 1.30m/s.Finally,the die-casting production experiment was carried out with the optimal process parameters,and the die-casting parts produced were tested.By comparing the flaw detection results with the numerical simulation results,it can be found that the numerical simulation results accurately reflect the areas with high shrinkage rate.Through microstructure analysis,it is found that the grains in the thin-wall area of the casting are fine and there is no coarse dendrite,and there is a small range of shrinkage porosity and small pores in the thick-wall area of the casting.The eutectic silicon structure at the thin wall position is finer than that at the thick wall position.The internal stress in the crystal of the thin-walled structure is smaller.The hardness of thin wall is about 103.6HV,and that of thick wall is about 101.6HV.The quality of die castings meets the requirements.