铝合金拉伸试样金属型模具优化

设计了一种采用不同浇注系统的铝合金拉伸试样金属型模具,以减少铸件的缺陷、提升铸件的质量。利用Pro CAST对铸造过程进行模拟,对拉伸试样充型凝固过程中的各物理场进行分析,预测其铸造缺陷和二次枝晶臂间距。确定优化模具的合理性后进行实验验证。实验结果表明:优化模具能够有效阻止前沿含有氧化薄膜的金属熔体进入型腔;优化模具的扇形流道,使充型过程平稳,避免型腔内出现卷气现象;试样能够实现顺序凝固,成功消除试样中的缩松、缩孔缺陷;优化模具试样的二次枝晶臂间距为33. 2μm,抗拉强度为215 N·mm-2,屈服强度为173 N·mm-2,断后伸长率为4. 5%。优化后的模具能有效地减少拉伸试样中的铸造缺陷并减小二次枝晶臂间距,提升了拉伸试样的力学性能。

Optimization on metal mold for aluminum alloy tensile specimen

A metal mold of aluminum alloy tensile specimen with different pouring systems was designed to reduce the defects of casting part and improve the quality of casting part,and the casting process was simulated by software Pro CAST. Then,the physical fields during the filling and solidification process of tensile samples were analyzed,and the casting defects and the secondary dendritic arm spacing were predicted. Furthermore,the rationality of the optimized mold was determined and verified by experiments. The results show that the optimized mold effectively prevents the metal liquid with oxide film in the front stage from entering the cavity,and the tapered runner in the optimized mold makes the filling process stable to avoid the phenomenon of gas filling in the cavity. In addition,the sample realizes solidified sequentially and successfully eliminates the shrinkage defect,the secondary dendrite arm spacing of specimen is 33. 2 μm,the tensile strength is 215 N·mm-2,the yield strength is 173 N·mm-2,and the elongation after fracture is 4. 5%. Thus,the optimized mold effectively reduces the casting defects in the tensile samples and the secondary dendrite arm spacing,and the mechanical properties of tensile specimens are improved.