核电SA508-3钢大型筒体环焊残余应力分析

Analysis of residual stresses on large-scale wall pipe circular weld of SA508-3 steel for nuclear power

关键词:  SA508-3钢  环焊缝  子结构  残余应力  数值模拟

Key words:  SA508-3 steel  circular weld  substructure  residual stress  numerical simulation

摘要:

为了准确地预测核电SA508-3钢的大型筒体环焊温度和残余应力变化规律,基于ANSYS有限元软件,引入子结构法优化焊接模拟过程,并比较模拟结果与试验数据.结果表明,文中采用的计算方法成功地模拟了更加接近真实的筒体环焊过程,且模拟结果与实测值基本吻合;焊缝上所有节点的热循环曲线相似,热影响区的模拟宽度为4 mm左右;筒体外表面焊缝中心线上任意节点的残余应力大小相近,仅在靠近筒体外表面焊缝中心线附近存在一定的轴向压应力,其它区域大部分为拉应力,环向保持较高的拉应力;筒体焊后产生内凹残余变形;结果可为分析大型筒体环焊残余应力提供参考数据.

Abstract:

The ANSYS software and substructure method were used to optimize welding procedure to accurately predict the distribution of welding temperature and residual stress in largescale pipe of SA508-3 steel for nuclear power. Comparing the simulated and experimental results,it was found that the computation method could successfully simulate the real welding process,and the calculated values agreed well with the measured ones. The thermal cycle curves of all nodes on the weld were similar,the simulated width of heat affected zone was about 4 mm. The residual stress values of arbitrary nodes in the weld centerline on outer surface of pipe were close to each other,however, axial compressive stress only occurred near the weld centerline on outer surface of pipe,tensile stress appeared in other areas with higher value in the circular direction. The pipe had a concave residual deformation after welding. The results could provide theoretical guidance for analyzing the residual stresses in girth welding of large scale pipe.