管子管板封口焊过程数值分析

Numerical Analysis on Welding of Steam Generator Tube-to-Tube Sheet

采用有限元分析的方法对国家重大专项CAP1400核电机组蒸汽发生器管子管板封口焊过程进行了模拟分析,研究了管子管板封口焊后残余应力及等效塑性应变,焊接温度场,焊接变形情况。结果表明:二次加热过程可以消除部分焊接应力;缩孔现象不受焊接应力的影响;焊后残余应力主要分布在热影响区位置,且靠近管板一侧残余应力更大;塑性变形区域主要分布在热影响区位置,且靠近管子一侧塑性应变更大;焊后管口略微膨胀,排除实际焊接过程中缩孔现象是由焊接应力产生的;焊接过程中管长基本不变,封口焊过程对换热管的间隙基本无影响。

In this paper,the finite element analysis method is used to simulate the welding of CAP1400 steam generator tube-to-tube sheet.The equivalent stress,equivalent of plastic strain,temperature field,welding deformation of tube-to-tube sheet are studied.The results show that the secondary welding process can reduce the residual stress.The residual stress and plastic deformation are mainly distributed in the heat-affected zone after welding,and close to the tubesheet the value is larger.Because of the inflation of nozzle after welding,the tube shrinkage may not be caused by welding stress.The circumferential deformation is less than 1/3 of the radial deformation.