中部槽焊接残余应力场的数值模拟

Numerical Simulation of Welding Residual Stress Field of Middle Pan

针对中部槽焊接易出现焊接裂纹的现象,基于SYSWELD有限元软件,针对某型号中部槽多层多道焊接的残余应力场进行了数值模拟研究。利用修正的双椭球热源,模拟了双丝电弧焊枪的移动加热过程,得到了焊后空冷至3 600 s时的残余应力场,绘制了沿焊缝和垂直焊缝2个不同路径上的残余应力曲线。研究结果表明焊缝与中板连接一侧的焊趾处纵向残余应力大于焊缝区新材料屈服应力,这是中部槽出现焊接裂纹的主要原因。

For the problem of cracks on the middle pan that appears in the welding, welding residual stress field was simulated by SYSWELD code for multi-layer and multi-pass welding. The mobile heating process of twin wire arc welding was simulated by the modified double ellipsoid heat source. The welding residual stress field was calculated at the 3 600 s after welding and air cooling. The two curves of residual stress- location were obtained on the middle pan along the centerline and perpendicular to centerline of the fifth weld seam. Results showed that the residual stress which occurs on weld toe side of the plate surface is greater than the yield stress of new material on the weld zone, which is the main reason of the crack initiation on the middle pan.