翅片管路焊接接头断裂原因分析

通过KYKY2800扫描电镜等技术手段对翅片管路焊接接头进行失效分析。分析表明，焊缝与2#环管的焊趾处存在有不连续的咬边，造成应力集中；在交变应力的作用下于咬边处产生微裂纹，并沿一定方向扩展（同时材料的不均匀性也为裂纹的扩展提供了有利条件），直至最后疲劳断裂，造成失效。最后提出了预防措施。

Failure Analysis on Welded Joints of the Finned Pipe

It was analyzed the cause of failure on welded joints of the finned pipe by KYKY--2800 scanning electron microscopy techniques. It was discovered that the main reason resulting in breaking was the weld defects at the welded joint： over undercut. Stress concentration exist in undercut, thus in the role of alternating stress, micro--cracks arose, and extended along a certain direction （at the same time material heterogeneity is also a favorable condition for crack propagation）, until the final fatigue fracture. Finally, the preventive measure was proposed.