高速列车铝合金车体枕梁搅拌摩擦焊接头残余应力分布特征

Residual stress distribution characteristics of friction stir welding joints on aluminum alloy body bolster of high speed vehicle

采用超声波法对铝合金枕梁部件搅拌摩擦焊(FSW)接头和熔化极气保护焊(MIG)接头分别进行了残余应力测量。结果表明,FSW固相焊接头的纵向应力和横向应力均为拉伸残余应力,其中纵向应力水平远高于横向应力。纵向应力在FSW焊缝两侧呈不对称分布特征,在搅拌头的前进侧应力值较高,而在返回侧应力值较低,最高应力位于前进侧的轴肩作用边缘处。MIG熔化焊接头在焊缝及近缝区的纵向应力和横向应力也为拉伸残余应力,且在MIG焊缝两侧呈对称分布特征,其中纵向应力高于横向应力,最高应力位于焊缝及热影响区。

Residual stress are measured by ultrasonic inspection on the friction stir welding（FSW） joints and MIG welding joints on aluminu,n body bolster of high speed vehicle respectively. Results show that both longitudinal and transversal stresses of solid phase FSW joints are tensile residual stress. The level of longitudinal residual stress is far higher than that of transversal stress. Longitudinal stress distributes asymmetrically in each side of FSW welds. The stress value is higher on the advancing side of FSW head,while is lower on the retreating side. The maximum stress is measured on the shoulder edge of the advancing side. The longitudinal and transversal stresses are also tensile residual stress in the MIG welded joints,and symmetrically distribute in the two sides. The longitudinal residual stress is higher than transversal stress and the maximum stress is measured in the weld and heat affected zone.