Research On Die Casting Technology And Defects Of Front Oil Seal End Cover

This paper takes the crankcase front oil seal end cap casting as the object of research,through test inspection,orthogonal test and numerical simulation,the initial process case and defects of the casting site for a comprehensive analysis and research,with the help of Flow-3D software to complete the design process and production process case optimization and production verification,the research results show that:The initial process design of the casting is a stepped parting surface,with the pouring system distributed along the outer contour of the casting,a long trapezoidal ingate gate,and an overflow tank located in the moving mold,which is connected to the atmosphere through the exhaust channel.Simulation shows that the aluminum liquid is ejected from the center plate area into the thick wall area,and the defect volume is about 2.4%;the solidification process simulation results are consistent with the filling,and insufficient hot spot and pressure transfer will increase the possibility of defects.Test analysis shows that there are three types of defects in the casting,shrinkage,shrinkage and mixed defects,mixed defects three-dimensional morphology is significantly different from shrinkage and shrinkage,the internal sidewall organization:cellular raisedα（Al）phase,curved eutectic（Si+α（Al））phase mixed sub-eutectic organization,lamellarβ（Al₉Fe₂Si₂）phase and square（Fe Mn）₃Si₂Al₁₅ phase.Due to the high temperature at the hot spot during solidification,the metamorphic treatment effect is weakened,and there is almost no sub-eutectic structure at the hot spot.α（Al）phase is continuous and wrapped with eutectic Si.Pressure and cooling rate change the Al-Si eutectic reaction,α（Al）phase changes from continuous to massive or dendritic,and lamellar eutectic Si refines to short rod shape.Optimization of The first optimized case,No.3 ingate gate to the side of No.4 ingate gate to reduce the impact on the front core of the ingate gate,while its width is expanded from 24mm to 32mm,the simulation shows that the flow rate of No.3 ingate gate increases,the corresponding position of filling ahead of time,and the convergence of liquid flow with No.4ingate gate to fill the flat plate area,improving the exhaust situation in the area,but the impact on pressure and solidification is weak,and the defect volume accounts for 2.1%.The defect volume is 2.1%.The second optimized case,all the ingate gates are moved to the right edge of the casting,the simulation shows that the aluminum liquid fills the edge area first,and then twice turns into the central flat plate area,the liquid flow is fan-shaped dispersion,filling is more chaotic,the solidification process does not show obvious changes,the defect volume accounts for 2.7%.In The third optimized case,all the ingate gates are opened in the lower part of the casting,the size and angle are adjusted,the simulation shows that a small amount of spatter is generated during the filling,and the gas is pushed to the overflow system to complete the filling more smoothly and neatly.The pressure in the left thick wall and lower area of the cavity is higher,and the pressure in the upper and edge areas is smaller,the distribution is as expected,the solidification process is obviously optimized,and the percentage of defect areas is 1.75%.Delaying the switching point of the press injection speed significantly reduces the volume of rolled gas when the metal liquid is filled.The orthogonal simulation test case was designed with mold temperature and injection temperature as factors,and nine sets of numerical simulation calculations of production process case were completed,and the optimal production process case was based on the defect volume ratio of 1.52%,in which the injection temperature was 665℃and mold temperature was 200℃.Based on the optimal design process case and the optimal production process case,production verification was carried out.The internal quality of X-ray inspection reflected that the original defects were eliminated and no new defects appeared,and the subcutaneous porosity rate decreased significantly after machining.