焊后热处理对FSW和TIG焊残余应力影响的数值模拟

Finite element simulations on effects of post weld heat treatments on residual stresses in FSW and TIG

为展示FSW在焊接残余应力方面的优势和特点,采用顺序热力耦合模型模拟FSW和TIG两种焊接构件的残余应力,在与已有文献验证对比的基础上,讨论和对比焊后热处理工艺对残余应力分布的影响。结果表明:FSW的焊后残余应力低于TIG焊接,在焊接厚度方向上,FSW的残余应力有较明显的变化,而TIG焊的残余应力变化很小;热输入功率的改变对TIG纵向残余应力的影响相对较小,而对FSW的影响较大;随着热处理温度的升高,焊后热处理对残余应力的降低作用越明显;同样的焊后热处工艺对TIG焊的残余应力降低更为明显。

To reveal the advantages of FSW in residual stress,the sequentially coupled thermo-mechanical model was used to simulate the residual stress in FSW and TIG. Based on the validation and comparison with published literatures,the effect of the post weld heat treatment（PWHT）on residual stress was discussed. Results indicate that the residual stress of FSW is obviously lower than that of TIG. Along the direction of thickness,the residual stress of FSW is different. But the residual stress is almost unchanged along thicknesses direction in TIG. The variations of the heat input can affect the residual stress in TIG more obviously than that in FSW. With the increase of the temperature in post weld heat treatment,the effect of PWHT on residual stress increases. Under the same PWHT,the decrease of residual stress is more obvious in TIG than in FSW.