A356.2铝合金轮毂局部增压铸造过程数值模拟

Numerical simulation of local pressurization casting process of A356.2 aluminum alloy wheel hub

采用ProCAST软件模拟了A356.2铝合金汽车轮毂在局部增压铸造技术下的充型和凝固过程,探究了铸件的温度场、缺陷分布和应力场。结果表明:铸件基本符合顺序凝固,但是部分区域出现了热节;缩松、缩孔缺陷主要分布在轮辐与轮辋交界处、轮辐与中间毂交界处以及轮辋某些区域;合适的浇注温度、模具温度以及局部机械加压可以有效地减少缺陷;等效应力大小由热应力与机械应力共同决定。正交试验优化后的压铸参数为:浇注温度t_(pouring)710℃,上模温度t_(upper die)340℃,边模温度t_(side die)360℃,下模温度t_(lower die)400℃,风压0 MPa,机械压力1.4 MPa。在此条件下由试验获得的轮毂缺陷最少,力学性能最好。

ProCAST software was used to simulate the filling and solidification process of A356.2 aluminum alloy automobile hub through local pressurization casting technology,and temperature field,defects distribution and stress field were investigated.The results show that the solidification is basically in sequence,but thermal centers appear at some regions.Shrinkage porosities defects are mainly distributed in the spoke/rim junction,spoke/center hub junction,and the partial region of rim.Proper pouring temperature,moulding temperature and local mechanical pressurization can eliminate the defects effectively.The effective stress is codetermined by the thermal stress and mechanical stress.The die-casting parameters optimized after the orthogonal test are as follows:pouring temperature of 710℃,upper die temperature of 340℃,side die temperature of 360℃,lower die temperature of 400℃,wind pressure of 0 MPa,and mechanical pressure of 1.4 MPa.Under the optimized conditions,the hub obtained from the test has the least defects and the best mechanical properties.