双相不锈钢管道全位置焊接残余应力三维有限元数值模拟

以热弹塑理论为基础，利用ANSYS非线性分析有限元程序，对双相不锈钢管道接头环焊缝残余应力进行三维数值模拟。建立了管道全位置焊接瞬态温度场和应力场三维移动热源模型，获得了环焊缝焊接接头轴向和环向残余应力的分布规律：在管道接头内表面的焊缝及近缝区的轴向和环向残余应力均为拉应力，随着离开焊缝距离的增加，由拉应力逐渐过渡为压应力。在管道接头外表面焊缝中心处的轴向残余应力为压应力，而环向残余应力为拉应力。从环向位置上的应力变化规律可以看出正半周和负半周的应力分布具有明显的对称性。研究结果为优化生产工艺，控制残余应力提供了理论依据。

Three dimensional finite element numerical simulation of residual stresses of all-position welding in duplex stainless steel pipe

On the basis of the thermal-elastic-plastic theory, a three dimensional finite element numerical simulation residual stress of girth welded duplex stainless steel pipes with ANSYS non -liner finite element program. Three dimensional FEM using mobile heat source for analysis transient temperature filed and welding stress filed in circumferential joint of pipes is founded. Distributions of axial and hoop residual stresses of the joint are investigated. The axial and the hoop residual stresses at the weldand weld vicinity on inner surface of pipes are tensile, and gradually transferred into compressive in base metal. The axial residual stresses at the weld and weld vicinity on outer surface of pipes is compressive while the hoop one is tensile. The distributions of residual stresses compared positive semi circle with negative -circle show distinct symmetry. These results provide theoretical knowledge for the optimization of welding process and the control of welding residual stresses.