基于数值模拟的铝合金薄壁管拉拔工艺优化

摘要

By using finite element simulation software LS-DYNA,the model for simulating the drawing process of thin-walled aluminum tube was established and the reason of rough surface,non-uniform thickness and material failure in the multi-pass drawing process were analyzed.The drawing process was improved by the combination of shape and size optimization method and verified by experiments.The results show that the contact force between material and die wall was non-uniform during the drawing process of thin-walled aluminum tube,and then the flow rate of metal along the drawing direction was inhomogeneous,which led to U-shaped lines on tube surface and edge failure.With shape and size optimization of blank and die bearing in the 3 rd-pass drawing process, the homogeneity of metal flow rate was significant improved,and the strain concentration was eliminated,and then the profile with high quality was fabricated.%使用 LS-DYNA 有限元软件，建立了铝合金薄壁管拉拔加工的仿真模型，对管材拉拔过程中表面质量降低、壁厚不均以及材料失效等问题进行了原因分析；采用形状与尺寸优化相结合的方式改进了拉拔工艺并进行了试验验证。结果表明：铝合金薄壁管在拉拔过程中，与模具发生非均匀接触，沿拉拔方向材料的流动速度不一致，导致成型后的成品表面出现 U 形纹路，并诱发棱边开裂失效；通过优化第三道次坯料及模具工作带的形状和尺寸，显著提高了拉拔加工过程中金属流动的均匀性，改善了应变集中问题，并获得了高质量产品。