厚壁铸钢件多层多道补焊残余应力分布仿真

Simulation of residual stress distribution in multilayer and multipass repair welding of thick-wall steel castings

为了降低在役汽轮机汽缸补焊后的残余应力,利用ABAQUS中的生死单元技术对存在缺陷的厚壁铸钢件多层多道补焊后的残余应力分布进行了仿真计算。在保证精度条件下,采用了分段式热源模型,研究了厚壁铸钢件补焊过程的热循环曲线及三维模型的焊接残余应力分布状态,分析了不同预热温度及不同层厚对补焊区域残余应力分布的影响,得到了厚壁铸钢件补焊所需的较为合理的预热温度区间和相应的层厚层道数量匹配的焊接修复方法。

In order to reduce the residual stress after repair welding of steam turbine cylinder in service,the residual stress distribution of defective thick-wall steel castings after multi-layer and multi pass repair welding was simulated by the birth and death element technology in ABAQUS.Under the condition of ensuring the accuracy,the segmented heat source model was adopted to study the thermal cycle curve of repair welding process and the distribution of welding residual stress in the three-dimensional model of thick-wall steel casting.The effects of different preheating temperature and different layer thickness on the residual stress distribution in the repair welding area were analyzed,and the more reasonable preheating temperature range and the corresponding welding repair method matching the layer thickness and the number of layers were obtained.