The Simulation And Technology Studies Of Low Pressure Die Casting On ZM6 Magnesium Alloy Rear Case Casting

In the paper,the forming process of ZM6 aero-engine rear casing casting with internal complex structures for its oil passages and more curved surface was settled by process design,calculation and optimization and making a practical casting plan.We choose the low pressure sand casting method and selected bottom rain type gating system with top riser through making reasonable design for gating system of the rear case casting.The design of airvents and riser can make the gas in mould get out successfully,as well as the runner can make the molten metal filling the mould smoothly.The sand mould and sand cores are made by Patternless Casting Manufacturing and 3D printing respectively.We use ProCAST software doing numerical simulation for the process of filling in scenario one at the temperature of 740 ℃,the result showed the shrinkage cavities were seen on the casting apparently.The defects have been eliminated by optimizing the gating system,which changed the risers shape with the casting and increased two ingates in scenario two,increased risers area and three sprues in scenario three.The results of simulating the filling and solidification process among 740 ℃,750 ℃ and 760 ℃ showed that the liquid filling process was unstable at 750℃ and 760℃,however the liquid filling process was stable at 740 ℃.We got the best pouring temperature is about 740℃.Aviation rear casing casting was made according to the optimizing casting process card.The appearance test results showed that the casting has complete structure and achieved the dimension precision CT7.The results of the fluorescence detection and X ray detection showed metallurgical defects haven’t appeared on the inside and the surface of casting.The result of the suppression of leakage detection showed that the casting has compact structure,mechanical performance testing and metallographic observation results showed that the casting has good microstructure and high comprehensive mechanical properties.Therefore,based on the analysis,experimental casting can meet the aviation standards and be used in environment of high temperature,high pressure and high speed.In this paper,the practical casting process for the ZM6 aero engine rear casing casting have decided by simulating,producing practically and optimizing the parameters.We adopt two types of rapid prototype technology to make sand mould and sand cores.It will have reference significance for producing the magnesium alloy castings with similar structure.