转向架侧梁生产及服役过程中的焊接残余应力研究

Study on the welding residual stress in the side beam of the subway bogie during the production and service processes

采用X射线衍射法(XRD)测试转向架侧梁在制造过程及疲劳试验过程中同一部位焊接的残余应力,获得焊接残余应力在生产及服役过程中的变化规律,为改进转向架制造工艺提供理论支撑。结果表明:侧梁来料基础件表面为压应力;转向架大部件焊后及热调修后残余应力整体分布不均匀,存在高值拉伸应力;构架热处理后焊接残余应力大幅度降低,残余应力趋于均匀化;构架喷砂后,焊接残余应力由拉应力转变为压应力,并在构架表面形成有利于疲劳性能的压应力层;构架疲劳试验600万次时,残余压应力不会发生松弛;构架疲劳试验1 200万次后,构架表面的残余压应力大幅度下降,应力逐渐松弛重新分布,且分布更为均匀。

The X ray diffraction method （XRD） was used to test the welding residual stress in the same part of the side beam of the bogie in the processes of production and fatigue test. The change rules of the wehting residual stress in the processes of production and service were obtained ,which provided theoretical support for improving the manufacturing process of the bogie. The results showed thai the surface for incoming side beam existed compressive stress. Residue pressure with non-uniform distribution and high tensile stress was found in the bogie parts after welding and heat repairing. After heat treatment, welding residual stress was greatly reduced, the residual stress tends to be uniform. After sandblasting,the residual stress on the beam surface was changed from tensile stress into favorable compressive stress,which benefited the fatigue property. After frame fatigue test of 6 million cycles,the residual compressive stress relaxation did not occur. After fatigue test of 12 million cycles, the residual compressive stress on the surface significantly decreased,while the stress was relaxed and redistributed to be more unih-nn.