| With the booming development of automobile industry,engine cylinder block has been playing as an important part of automobile parts.Aluminum alloy has the characteristics of light weight and high strength,thus engine cylinder production using aluminum alloy can effectively reduce the weight of the engine,and achieve the purpose of automobile lightweight.As a casting method with high production quality,pressure casting has been widely used in the production of engine cylinder block.In recent years,great progress has been made in numerical simulation technology of casting,which can optimize process,improve casting quality and reduce production cost.Aluminum alloy engine cylinder is taken as the research object in this paper,using ProCAST software to simulate the cylinder filling and solidification process,and optimize the process parameters,and then optimize the aluminum alloy composition to achieve the purpose of cost reduction.The results of numerical simulation of the process parameters of aluminum alloy engine cylinder show that:by calculating the projected area of the casting,the expansion force,the locking force and the alloy weight are determined,and DCC1250 horizontal cold chamber die casting machine is selected.The numerical simulation process parameters of the cylinder block are as follows:injection specific pressure of 80MPa,filling speed of 25～30m/s,filling time of 0.040～0.060s,aluminum alloy pouring temperature of 620～720℃,mold preheating temperature of 180～240℃,injection speed range of 5.2m/s～12.1m/s.According to the shape and size of the cylinder block part drawing,the closed gating system is adopted,and the overflow groove is arranged around the cavity,and its shape and size are determined,which lays a foundation for the subsequent optimization of die casting process parameters by numerical simulation.The effects of preheating temperature,injection speed and pouring temperature on ADC12aluminum alloy engine block casting were studied by orthogonal experimental analysis.The results of numerical simulation show that:Through the shrinkage ratio of the simulation results,the poor and variance analysis to get the greatest effect in the mould preheating temperature,with the increase of mould preheating temperature,shrinkage porosity defect and cracking formation of castings tend to be smaller,injection speed,with the increase of injection rate,the less shrinkage porosity defect formation of castings,the pouring temperature affect the minimum,with the loss of the pouring temperature,The less shrinkage cavity and porosity defects of casting;Injection speed is 12m/s,pouring temperature is 680℃,mold preheating temperature is 240℃,casting shrinkage cavity defects are the least,casting quality is the best,quality index is 90.The results show that the filling process of alloy 2~#(1.1wt.%Cu,2wt.%Fe,2wt.%Mn)is the most stable among the three materials designed,and the filling velocity fluctuation is the smallest at the key point where the thick and thin wall intersect,which greatly reduces the probability of casting porosity.At the casting temperature of 680℃,material 2~#has the lowest thermal conductivity(81.1627 W/m·K),the highest density(2541.05 kg/m3),and the best fluidity.During the solidification process,material 2~#has the fastest solidification speed and the solidification time is 115.8s.The casting quality is the best and the shrinkage cavity defects are the least.Compared with ADC12 aluminum alloy,the content of Cu in material 2~#decreases,while the content of Fe and Mn increases,and the defects of shrinkage cavity and porosity in material 2~#is the least.Material 2~#not only has the best casting quality,but also meets the requirements of cost reduction. |
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