冷却剂管道取样管焊缝裂纹分析

Analysis of weld crack in sampling pipe of reactor coolant pipe

通过金相、扫描电镜等方法,对某项目核电机组主管道预制阶段的取样管焊缝裂纹失效进行分析。结果表明,该裂纹主要是水压试验后的机械加工过程引起的取样管侧焊趾附近的疲劳裂纹。同时,焊缝外表面焊趾附近形状的突变、加工沟痕较深等也是引起疲劳开裂的主要因素。

Through metallographic microstructure and SEM(scanning electron microscope) analysis,the crack in the weld of sampling pipe of reactor coolant pipe in the prefabricate phase was analyzed.The results show that the crack near the weld toe is fatigue crack formed during the machining process after hydrostatic test.And the changes of the weld toe shape and the depth of the machining are also the main factor of the crack.