焊后热处理消除管道环缝焊接残余应力的有限元模拟

以ABAQUS模拟软件为基础，创建管道环缝二维轴对称有限元模型，利用完全耦合方式计算了304不锈钢管焊接过程中的温度场和残余应力场，并在焊接完成后的残余应力场的基础上进行了焊后热处理工艺过程的有限元模拟。结果表明:二维轴对称模型能够有效地模拟304不锈钢管焊接热力耦合机制，相较于三维模型单元数目更少，节省大量计算时间；热处理后的残余应力场与热处理前相比，厚度方向残余应力降低，环向和纵向残余应力没有降低，但应力集中位置明显减少，应力分布较为平缓；焊后热处理过程中的塑性应变和高温蠕变是残余应力消除的力学机制，其中塑性应变起主要作用。

Finite Element Simulation of Eliminating Welding Residual Stress of Pipe Girth Weld by Post Weld Heat Treatment

Based on ABAQUS simulation software and the two-dimensional axisymmetric finite element model of girth weld, the temperature field and residual stress field in the welding process of 304 stainless steel pipe are calculated by the full coupling method. Based on the residual stress field after welding, the finite element calculation of post welding heat treatment process is carried out. The results show that the two-dimensional axisymmetric model can effectively simulate the thermal mechanical coupling mechanism of 304 stainless steel pipe welding, and save a lot of calculation time compared with the three-dimensional model. Comparing with the residual stress field before heat treatment, the residual stress in the thickness direction is reduced, the residual stress in the circumferential and longitudinal directions is not reduced, but the stress concentration position is significantly reduced, and the stress distribution is relatively gentle. Plastic strain and high temperature creep during post weldin heat treatment are the mechanical mechanisms of residual stress relief and the former plays an important role in this study.