钢铝异种金属回填式搅拌摩擦点焊的数值模拟研究

Numerical Simulation Study of Refill Friction Stir Spot Welding of Steel/Aluminum Dissimilar Metals

本文提出一种模拟异种金属双层板搭接回填式搅拌摩擦点焊下扎过程的方法。以2 mm厚度的AA6061-T6铝合金板和AISI4340普通钢板为研究对象,建立完全热力耦合模型以及库伦摩擦和常应力摩擦混合的热源模型,利用DEFORM软件模拟焊接过程中的温度场、搅拌头受力情况和材料变形情况。结果表明:搅拌针与下板材接触时的下扎距离大于上板材厚度,焊接区域结合面温度分布均匀,板材结合面在搅拌针施加力的方向发生搅拌针底边缘部凹中心凸的变形,凹陷变形方向与温度扩散方向一致,结合面的变形是造成钩状缺陷的主要原因。

A simulation method for simulating the plunge process of refill friction stir spot welding of dissimilar metals double-sheet overlap was proposed.AA6061-T6 aluminum alloy and ordinary AISI4340 steel plates with 2 mm thickness were selected as the research object,full thermo-mechanical coupled model and the heat source model of combining Coulomb friction with constant stress friction were established.Temperature field,force of stirring tool and material deformation during the process of welding were simulated through DEFORM software.The results show that the plunge depth of stirring pin when the pin contacts with the lower sheet is greater than the thickness of the upper sheet,the interface temperature distribution of the weld zone is uniform,and periphery of the bonding interface corresponding to pin edge is sunken and the center bulges in the direction of the force applied by the stirring pin,sunken deformation direction is consistent with the temperature diffusion direction,the deformation of interface is the main cause of hook defect.