数值计算模拟工艺参数对管道环焊缝残余应力的影响

Effect of simulated welding parameters on pipe girth weld residual stresses

以热-弹塑性理论为基础,建立了厚壁管环焊缝残余应力的二维轴对称有限元模型,利用ANSYS有限元程序分析了三种焊接工艺参数对管道环焊缝残余应力的影响,计算中考虑了材料热物理性能参数和力学性能参数的温度相关性。结果表明,管道内表面焊缝和近缝区的轴向和环向残余应力均为拉应力,而管道外表面焊缝和近缝区的轴向残余应力和环向残余应力均为压应力;接头内表面应力水平高于外表面;残余应力的最大值均位于距管道外表面一定距离处,其数值接近于材料的屈服应力;随着焊接热输入的增加,残余应力峰值变化不大,塑性变形区宽度增加。

A two-dimensional axial-symmetric finite-element model of welding residual stresses of thick-wall pipe has been proposed based on the theory of thermal-elastoplasticity. Using ANSYS finite-element code, the effect of three groups of welding parameter on girth weld residual stresses of pipe is analyzed. The temperature correlation of thermal physical property parameter with mechanical property parameter is considered during the simulation. The results show that both the axial stresses and the hoop stresses are tensile stress in the pipe inner surface weld and near weld section, but they are compression stress in the pipe outer surface weld and near weld section. The stress value near the inner surface is higher than the one of the outer surface in the joint; the maximal value of residual stresses appears in the certain distance beneath exterior surface of the pipe, and the value is close to the yield stress of base metal. The size of plastic deformation zone increases with the increase of heat input while peak value of residual stresses change little.