包含拉延残余应力的U形薄板工件点焊变形分析

Analysis of deformation of spot welding U-shaped thin plate workpiece with stamping residual stress

以铝合金薄板U形件为研究对象,将拉延成形和电阻点焊顺序耦合,研究了拉延残余应力对U形件焊后变形的影响。在此基础上,将改善应力状态分布的热处理法应用到工件点焊模型,分别在焊前和焊后对U形件整体或局部进行热处理,研究不同条件下U形件的整体变形状态。结果表明：拉延残余应力在一定程度上会约束U形件的焊接变形;对完成拉延加工的U形件进行焊前热处理或焊后热处理,均能减小U形件的整体变形量,且焊前热处理对U形件整体变形量的控制优于焊后热处理;抵消拉延加工中U形件因回弹效应产生的位移偏移量的最有效方案为在焊前对U形件的侧壁进行热处理再进行电阻点焊。

Taking aluminum alloy thin plate U-shaped workpiece as the research object and coupling stamping forming and resistance spot welding sequentially,the effect of stamping residual stress on post-weld deformation of U-shaped workpiece was studied. On this basis,the heat treatment method to improve the stress distribution state was applied to the spot welding model of U-shaped workpiece. The Ushaped workpiece was heat-treated in whole or in part before and after welding respectively to study the overall deformation of U-shaped workpiece under different conditions. The results show that stamping residual stress constrains a certain range of welding deformation of Ushaped workpiece. The pre-weld heat treatment and post-weld heat treatment are respectively applied to the stamped U-shaped workpiece,and both methods can reduce the overall deformation of the U-shaped workpiece,and the pre-weld heat treatment is better than the postweld heat treatment on controlling the overall deformation of U-shaped workpiece. The most effective solution for offsetting the displacement of the U-shaped workpiece due to the rebound effect during the stamping process is to perform a pre-weld heat treatment on the side wall of the U-shaped workpiece following by resistance spot welding.