不同充型条件下应力框铸件的力学性能

Mechanical Properties of Stress Frame Casting Under Different Filling Conditions

通过实验与数值模拟方法研究了自由充型和低压浇注两种充型方式对A357铝合金应力框铸件铸态组织的影响,并采用拉伸实验、SEM和EDS对T6热处理后两种铸件的力学性能及断口形貌进行了观察。结果表明:采用低压浇注可以减少铸件的区域缩松与微观缩孔,A357铝合金铸态断裂以沿晶断裂为主,裂纹起源于组织缺陷处并不断生长增殖直至铸件发生断裂;T6热处理后铸件主要发生韧窝断裂,断口上交错分布一定数量的沿晶断裂,华铸CAE数值模拟研究证实了低压浇注充型方案的优越性。

The influence of gravity filling and low-pressure filling on the cast structure of A357 alumi- num alloy stress frame was investigated by test and numerical simulation methods. The mechanical properties and fracture morphology of two castings were also observed with the use of tensile test, SEM and EDS after T6 heat treatment. The results indicate that low-pressure filling can reduce the casting shrinkage and micro-cavity region. Crystal fracture is the principal split pattern of A357 alumi- num alloy in casting state, cracks appear and fast grow until casting fracture from the defect area. Dimple rupture is the main fracture factor with some crystal fracture after T6 heat treatment. China cast CAE simulation study confirms that the low-pressure filling is superiority.