核电管道安全端异种金属焊接接头表面堆焊的有限元分析

Finite element analysis of the overlay welding on a nuclear nozzle safe-end dissimilar metal weld joint

根据热弹塑性有限元分析原理,建立核电管道异种金属焊接接头表面堆焊修复的有限元模型。应用ANSYS软件模拟某核电厂稳压器安全端接管堆焊修复试验过程,计算分析焊接温度场和应力场及焊接残余应力。结果表明,焊接过程中的不均匀热过程直接引起了复杂的应力状态。焊接过程中,环向应力变化比轴向应力快,环向残余应力比轴向残余应力大。堆焊后,在原管道内表面原焊缝附近形成了压缩残余应力,沿半径方向残余应力由拉应力逐渐向压应力过渡。

Based on thermal elastic-plastic finite element analysis theory,a finite element model for the overlay welding on a nuclear-nozzle dissimilar metal weld joint was built. By ANSYS software,the temperature field and stress field were sinmlated and the weld residual stress distribution was analyzed,which showed that inhomogeneous thermal effect results in complicated stress state during the welding process. During the overlay welding,the hoop stress varied more rapidly than the axial stress,and the hoop residual stress was greater than the axial residual stress. By the overlay welding, the tensile residual stress was found at the pipelineoutside surface. The pipeline stress deceased gradually from the outside to the inside,and the compressive stress was found in the initial weld and its adjacent zone at the pipeline-inside surface.