蒸汽发生器管子管板胀焊结合残余接触应力分析

Analysis of Residual Contact Stress of Pipe and Pipe Sheet of Steam Generator by Expanded Joint and Welding

采用有限元方法模拟蒸汽发生器管子管板的胀焊结合工艺过程,研究不同胀接压力下管子管板残余接触应力的分布情况、焊接温度场对管子管板残余接触应力的影响,以及未胀接区域长度对管子管板胀接区域残余接触应力的影响。分析结果表明,在胀接压力作用下,管子管板两端产生环向应力峰值,环向应力峰值随胀接压力的增大而增大,且管子过渡区域环向应力大于轴向应力。在焊接温度场作用下,靠近焊接区域的管子管板会发生应力松弛现象,应力环消失。随着未胀接区域长度的增大,焊接热影响减弱。当未胀接区域长度大于14 mm时,应力环会再次出现,且数值相对较小。先胀后焊的接头处焊缝区域残余接触应力最大,管桥间残余接触应力最小。对于胀焊结合工艺,需结合实际工作情况,考虑焊接对胀接区域应力松弛的影响。

The finite element method was used to simulate the bonding process of the pipe and pipe sheet of the steam generator by expanded joint and welding,and explore the distribution of the residual contact stress of the pipe and pipe sheet under different pressures for expanded joint,investigate the influence of the welding temperature field on the residual contact stress of the pipe and pipe sheet,and the influence of the length of the unexpanded joint area on the residual contact stress at the expanded joint area of the pipe and pipe sheet.The analysis results show that,under the action of the expanded joint pressure,the peak value of the hoop stress occurs at both ends of the pipe and the pipe sheet.The peak value of the hoop stress increases with the expanded joint pressure,and the hoop stress in the transitional region of the pipe is greater than the axial stress.Under the action of the welding temperature field,stress relaxation will occur in the pipe and pipe sheet near the welding area and the stress ring will disappear.In company with the increased length of the unexpanded joint area,the influence of welding heat decreases when the length of the unexpanded joint area is greater than 14 mm,the stress ring will appear again,and the value is relatively small.The residual contact stress in the weld area of the joint that is expanded first and then welded is the largest,and the residual contact stress between the pipe bridges is the smallest.For the bonding process of expanded joint and welding,it is necessary to combine the actual working conditions and consider the influence of welding on the stress relaxation of the expanded joint area.