X80钢曲面对接焊缝残余应力尺寸效应

以试验测得的X80钢高温性能参数为基础建立了曲面对焊结构仿真模型，并进行了试验验证，研究了曲面外径、曲面壁厚和焊缝宽度等尺寸效应对曲面对接焊缝残余应力分布的影响规律。结果表明：曲面外径、曲面壁厚和焊缝宽度的变化均会对曲面对接焊缝残余应力的分布规律产生影响；随着曲面径向截面面积的增大，焊趾处径向残余拉应力逐渐增大，残余压应力峰值逐渐减小；曲面径向截面面积和焊缝宽度的增加，均会引起焊趾处残余拉应力峰值的增大并导致曲面对焊结构中焊接残余应力水平的升高，降低结构整体的耐腐蚀性能和疲劳性能；在选用曲面壁厚小于4 mm的曲面结构进行工程设计时，焊接残余应力分布对壁厚的变化十分敏感，极易导致结构内部残余拉应力的增大并产生应力集中区域。

Dimensional Effects on Welding Residual Stress of Curved Butt Weld of X80 Steel

Based on the high temperature performance parameters of X80 steel measured in the experiment, a simulation model of the curved butt-welded structure was established and verified by the test. The effects of curved outer diameter, curved wall thickness, and weld width on the residual stress distribution of the curved butt-welded joint were studied. The test results show that the variation of curved outer diameter, curved wall thickness and weld width will affect the residual stress distribution of curved butt-welded joint. With the increase of the curved radial section area, the radial residual tensile stress in the weld toe rises gradually, and the peak value of residual compressive stress decreases gradually. The augment of the curved radial section area and the weld width will increase the peak value of residual tensile stress in the weld toe and the welding residual stress level of the curved butt-welded structure, and reduce the corrosion resistance and fatigue performance of the whole structure. The welding residual stress distribution is very sensitive to the change of wall thickness when the curved surface structure with the curved wall thickness less than 4 mm is used, which can easily increase the residual tensile stress and lead to the stress concentration area in the structure.