以小口径厚壁12Cr1MoVG珠光体耐热钢管多层多道焊接接头为对象，使用有限元模拟软件，采用生死单元法，计算焊接接头中的残余应力。计算结果表明：焊接接头外壁焊缝附近区域的残余应力为压应力，母材端的残余应力变化幅度要比焊缝区的小；焊接接头内壁焊缝及热影响区的残余应力为压应力，而母材承受拉应力。通过对比可知焊接接头内、外壁轴向残余应力分布的计算结果与实测结果高度吻合，说明数值模拟方法可以为管状接头的焊接工艺评定提供便利、可靠的技术支持。

Residual stress of the multi-layer and multi-pass welding joints of the small-caliber thick-wall 12Cr1MoVG steel tubes was calculated by the finite element modeling (FEM) simulation software and the birth-death element method. The calculation results show that the residual stress in the area near the welding seam of outer wall of welded joint was compressive stress, and the change range of residual stress at the base metal end was smaller than that in the weld area. The residual stress of the inner wall weld and heat affected zone of welded joint was compressive stress, while there was tensile stress in the base metal. Through comparison, it could be seen that the calculation results of the axial residual stress distribution in the inner and outer walls of welded joint were highly consistent with the measurement results, which showed that the numerical simulation method could provide convenient and reliable technical support for the welding procedure qualification of tubular joints.