TA15钛合金搅拌摩擦焊金属流动的有限元模拟

Finite Element Modeling of Plastic Metal Flow in Friction Stir Welding of TA15 Titanium

摘要: 本文采用有限元分析软件DEFORM-3D对TA15钛合金搅拌摩擦焊(FSW)过程中搅拌头周围金属的流动进行了数值模拟。经模拟，当焊接参数选取旋转速度为800 rmp，焊接速度为36 mm/min时，搅拌头周围金属的流动整体呈现漏斗状，与搅拌头外形轮廓相似，而且金属的流动关于焊缝中心并不对称。金属的流动速度随着其与搅拌头中心线径向距离的增加而增加，并且随着焊件厚度的增加，金属的流动能力逐渐越弱。对焊接工艺参数的作用分析发现，旋转速度和焊接速度的大小影响焊接过程的热输入，在一定范围内，随着旋转速度的增加，热输入量增加，金属的流动能力增强，焊缝成形就较好；在一定范围内，随着焊接速度的降低，也表现出类似的特征。

Abstract: Metal flow field around the rotation tool in friction stir welding workpiece is simulated numerically by using finite element method analysis software DEFORM-3D. The welding parameters are as follows: the rotation tool rotates at a rate of 800 rmp, and marches at a speed of 36 mm/min. The whole metal flow field shows that the metal around the rotation tool flows into a hopper-like zone similar to the shape of rotation tool, and the flowing field is asymmetrical with the welding central seam. It is found that linear velocities increase with the radial distance from central axis of welding tool increasing, and material’s flowing ability gets weakened at bottom of workpiece compared to the surface. By changing the rotating rate and marching speed, heat input is affected. Heat input increases with the rotating rate increasing within a certain range, leading to a better flowing ability of metal and a better welding seam forming. The similar conclusion is indicated with the decrease of marching speed.