某输气管线环焊缝泄漏失效分析

为了分析某输气管线环焊缝泄漏失效原因，预防类似事件发生，通过磁粉检测、夏比冲击功测试、金相分析和扫描电镜等方法对环焊缝泄漏原因进行了分析。结果表明:环焊缝存在原始裂纹是管线发生泄漏的主要原因，受补焊作业影响，原始裂纹在焊接时已经形成，在附加应力、运行压力及焊接残余应力的共同作用下，焊接裂纹优先在晶粒粗大和高应力处等敏感位置相互连接，最终发生泄漏。建议提高管线焊接质量，并加强无损检测力度。

Leakage Failure Analysis of Some Gas Transportation Pipeline Circumferential Weld

In order to analyze the leakage failure reason of some gas transportation pipeline circumferential weld and prevent the similar incidents. The leakage failure reasons of circumferential weld were analyzed by magnetic particle testing, Charpy impact test, metallographic examination and scanning electron microscopy. The results showed that the original crack existing in circumferential weld is the main reason. Influenced by repair welding operation, the original crack formed in the welding. Under the combined action of the additional stress, running pressure, and welding residual stress, the welding cracks were interconnected in some sensitive positions, priority in coarse grains and high stress areas, eventually leaked. It is suggested that to improve the quality of pipeline welding, and strengthen the nondestructive testing.