核电站中压安注箱不锈钢衬里焊接层缺陷分析

Failure Analysis for Cracks on Steel Liner Welding Area of Accumulator from Nuclear Power Plant

某核电站中压安注箱内壁不锈钢衬里的部分焊缝周围存在一些裂纹,经检查发现,裂纹主要位于堆焊层与不锈钢衬里的搭接部位及附近,裂纹的形貌呈撕裂状,同时裂纹附近基体轧制纤维组织有变形硬化。推测安注箱出现裂纹的原因是应力造成的机械开裂。分析认为,打压试验的内压和焊接残余应力是安注箱的主要应力来源。

Some cracks on the steel liner welding area of accumulator were found. The inspecting results show that the cracks mainly locate near the joining area of welding and parent material. The crack characteristics present mechanical crack, moreover, the rolling microstructure near the crack generates deformation and hardening. So, the reason for the cracks in the accumulator is considered to be mechanical crack by stress. The hydrostatic test and welding residual stress are considered to be the mainly stress source,