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套管修复是一种重要的在役焊接修复技术,然而在操作过程中由于内压和温度场的影响会不可避免地产生焊接残余应力,对应力腐蚀开裂造成很大的影响。本文采用有限元法对套管修复产生的焊接残余应力进行研究,编写了套管修复纵向双工焊接和环向焊接的移动热源子程序,与套管内压进行耦合计算,得到了套管温度场及应力场分布规律。结果表明,环焊缝焊接接头处产生的环形应力最大,轴向应力次之,径向应力最小。内管上纵焊缝区域的残余应力很小,对内管强度不产生影响。在套管纵焊缝和环焊缝的T型接头处的应力水平较高,已经达到材料屈服强度,成为最薄弱环节,应该引起足够的重视。
Casing repair is an important in-service welding repair technique. However, due to the influence of internal pressure and temperature field, welding residual stress will inevitably occur during operation, which will greatly affect stress corrosion cracking. In this paper, the finite element method was used to study the welding residual stress produced by casing repairing, and a subroutine of moving heat source for casing repairing longitudinal duplex welding and circumferential welding was compiled. Coupled calculation with casing internal pressure, the casing temperature field And stress field distribution law. The results show that the ring joints produced by the girth weld have the highest ring stress, the second axial stress, and the smallest radial stress. The residual stress in the longitudinal weld area on the inner pipe is small, which does not affect the inner pipe strength. The high stress level at the T-joint of casing longitudinal weld and girth weld has reached the yield strength of the material and becomes the weakest link, which deserves sufficient attention.