马氏体相变对9%Cr热强钢管道多道焊接头残余应力演化的影响

发布时间：2018-08-07 21:36

【摘要】：使用有限元软件Abaqus计算了考虑马氏体相变影响时9%Cr钢管道多道接头中的应力演化过程,并分析了马氏体相变在应力演化中的作用。结果表明,在管道纵截面上,环向和轴向残余应力的分布相似,但环向残余应力较大。环向和轴向残余压应力的最大值均出现在末道焊缝及热影响区,残余拉应力的最大值则出现在管道中部的焊缝及热影响区,而管道内壁附近的残余应力较低。在末道焊缝附近,发生在较低温度下的马氏体相变不仅抵消了焊缝和热影响区热收缩所形成的拉应力,并且形成了显著的压应力,但马氏体相变并没有消除次表层焊缝显著的残余拉应力。末道焊道对多道焊接头残余应力的影响最大,其原因是马氏体相变虽然在先焊焊缝中形成了很高的压应力,但后续焊道的焊接热循环会显著降低该压应力,使最终结果表现为马氏体相变只显著地降低了末道焊缝及其热影响区内的拉应力,并形成了显著的压应力。马氏体相变对管道外壁附近残余应力的影响较大,而对管道内壁附近残余应力的影响较小。
[Abstract]:The stress evolution process in multi-pass joints of 9%Cr steel pipeline considering the effect of martensite transformation was calculated by using finite element software Abaqus, and the effect of martensite transformation on stress evolution was analyzed. The results show that the distribution of annular and axial residual stresses in the longitudinal section of the pipeline is similar, but the circumferential residual stress is larger. The maximum values of circumferential and axial residual compressive stress are in the final weld and heat affected zone, while the maximum of residual tensile stress is in the weld and heat affected zone in the middle of the pipeline, while the residual stress near the inner wall of the pipeline is lower. Near the end weld, the martensitic transformation at lower temperature not only counteracts the tensile stress caused by the thermal shrinkage of the weld and the heat-affected zone, but also forms a significant compressive stress. However, martensitic transformation does not eliminate the significant residual tensile stress of the subsurface weld. The effect of the end pass welding pass on the residual stress of the multi-pass welding joint is the greatest. The reason is that although the martensitic transformation forms a very high compressive stress in the welding seam of the first welding, the welding thermal cycle of the subsequent welding pass will significantly reduce the pressure stress. The final results show that the martensitic transformation only significantly reduces the tensile stress in the final weld and its heat-affected zone, and forms a significant compressive stress. The effect of martensitic transformation on the residual stress near the outer wall of the pipeline is greater than that on the residual stress near the inner wall of the pipeline.
【作者单位】：武汉大学动力与机械学院;哈尔滨工业大学先进焊接与连接国家重点实验室;河南第一火电建设公司;
【基金】：国家自然科学基金项目Nos.51374153和51574181 先进焊接与连接国家重点实验室开放课题项目No.AWJ-Z15-02~~
【分类号】：TG404

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