Finite Element Simulation On Warm Forming Of Heat-resistance Aluminum (FVS0812) Semispherical Component

Heat-resistant aluminum alloy (FVS0812) has drawn wide attention due to its excellent properties over the range of 523~723K. However, comparing with steels, the ductility of FVS0812 is poorer and it causes great difficulty in drawing process. In this thesis, The warm tensile properties of FVS0812 sheet which was prepared by spray deposition-rolling process were studied, and using the finite element analyze software– DEFORM which developed by SFTC, the formability in different warm forming technologies was studied on the base of semisphere– shape warm drawing experiment. Tensile tests were carried out at condition of elevated temperatures and varies strain rates. The range of temperature was 523~723K and the strain rate was 0.001~0.1 s-1. The result showed that FVS0812 had high strength and excellent stability at high temperature. The yeild stress maintained about 110MPa at the temperature of 723K and the strain rate of 0.1 s-1. The maximum elongation tended to grow rapidly while the temperature reached 623K, which indicated the warm forming process should be held at the condition of 723K. Furthermore, a constitutive equation using updated Fields and Backofen equation was established.With the help of the finite element method (FEM), influencing factors to formability caused by different warm forming technologies were studied. The fracture area predicted by simulation went along well with the experiment. Comparing to experiment, the critical Damage value was 0.24.Simulation result also showed that using cold punch, reducing blank holder force(BHF) and using good lubricant would benefit the distribution of strain and stress on the workpiece. Deformation behaviors caused by traditional drawing technology and double layer drawing technology were much alike, while in the case of packed-layer drawing the behavior changed a lot. Points from different deformation area were picked for strain and stress analyzing. It was concluded that distribution of strain could benefit from packed-layer drawing greatly. When choosing materials for packing layers, high stength and high ductility materials were preferred. And it was also suggested that the upper and the lower layer should be the same material as well.Three different characteristics from different drawing technologies were discribed by the finite element analyse, which explained the different effects caused by the technologies. Meanwhile, the optimized process was pointed out.