Numerical Simulation Study On 7A09 Gravity Casting Process And Equipment Optimization

The gravity tilting casting equipment for the production of 7A09 aluminum alloy ingot,developed by Jiangxi Xiongying Aluminum Co.,Ltd and Key Lab of Near Net Forming in Jiangxi Province.In this paper,the gravity tilting device was modeled and simulated by AnyCasting.The steps of the software operation of the simulation were described in detail.The content of the pouring cup was determine by forming merits.The speed of tilt was determined by the maximum velocity of liquid metal.The preheating temperature of the device was determined by shrinkage hole,finally solidified layer depth(residual melt volume)and the probability distribution of defects.The pouring temperature was determine by the speed of casting cavity and ingot surface oxide content.The optimum process parameters of the gravity tilting device were: 50% of the content of gate cup,the1/14 ?/rad of speed with tilt,the preheating temperature of 100? and the pouring temperature of 700?.The reliability of AnyCasting for gravity tilting casting simulation was verified by experiments.Based on the optimal process parameters,well ingots can be obtained.Microstructures of the ingot produced by gravity tilting casting were analyzed,and the result shows that grain at the bottom was fine,and round,most was nearly spherical or rosette.By the Image Pro Plus6.0 estimating,the average equivalent grain diameter is 65 ?m,the average shape factor is 0.58 on tilting casting condition,;and the average grain diameter of semi continuous ingot molding process was 184?m,the shape factor is 0.08.During the tilting process of the device,the strong convection was generated among the metal liquid,which was beneficial to refining the grain.The mechanical properties of ingot formed by gravity tilting and semi continuous were compared.The yield strength,tensile strength and elongation of the former are better than that of the latter.The casting and sand mold structure of the existing tilting device were optimized.It can increase the cooling strength and shorten the solidification time by changing the steel mould into the copper mold in the composite mold.By optimizing the sand,the metal liquid can fill more orderly and smoothly.