铝合金薄板焊接接头残余应力分析

Research on residual stress of MIG welded joint on aluminum profiles

铝合金型材已经被广泛用作高速列车车体材料,其结构件焊接接头的服役安全可靠性至关重要。残余应力对接头的疲劳寿命影响很大,能够准确、无损、快速对焊接结构的残余应力进行测试。分别采用小孔法及X射线衍射法进行残余应力测试,通过对比分析两种方法测量的焊接接头残余应力的分布及数值,发现小孔法测量数值稍大于X射线衍射法;射线法测得数值波动范围较小孔法大,其主要原因是测量试件表层应力。但两种方法测量结果的总体趋势一致,故采用无损的X射线衍射法测量3 mm5083-H111薄板的MIG焊接头是可行的。

Aluminum profiles are widely used as the materials for high speed train body, thus the service safe reliability of the welded joints on structure is important for the whole system. Residual stress has a great influence on the fatigue life of joint, so a accurate,non-destructive and quick test of the residual stress on aluminum profiles for high-speed train is a significant work. The residual stress of the MIG welded joints on 3 mm thickness 5083-H111 aluminum profiles are investigated by blind hole-drilling method and X-ray diffraction（XRD）method in this paper. It shows that the values of residual stress tested by blind hole-drilling method are lager than those tested by X-ray diffraction（XRD）method,and the latter has larger variation range of the values,this is mainly caused by the different test depths. However, the overall trend of results of two methods is consistent, which means it＇s feasible to test residual stress of the MIG welded joints on 3 mm thickness 5083-H111 aluminum profiles by X-ray diffraction（XRD）method.