0Cr18Ni9不锈钢天然气管线的泄漏原因

Leakage Reason of 0Cr18Ni9 Stainless Steel Natural Gas Pipeline

某海上天然气输送管线采用0Cr18Ni9无缝钢管,管线在安装结束后,在水压试验时发现有泄漏现象。利用直读光谱仪、拉伸试验机、光学显微镜、扫描电子显微镜等分析手段,对泄漏失效的天然气管线进行了分析。结果表明:泄漏管线材料的冶金质量符合技术要求,但管线内表面泄漏部位存在翘皮,在翘皮和基体之间产生了缝隙腐蚀,蚀坑穿透管壁导致管线泄漏。

0Cr18Ni9 seamless steel pipe was used in an offshore natural gas transmission pipeline.After the installation of the pipeline,a leakage was found during the water pressure test.The leaked natural gas pipeline was analyzed by direct reading spectrometer,tensile testing machine,optical metallurgical microscopy,scanning electron microscopy and other analysis methods.The results show that the metallurgical quality of the leaked pipeline met the technical requirements,but there was a warped skin on the inner surface of the pipeline,and crevice corrosion occurred between the warped skin and the substrate,resulting in the pipeline perforation and leakage.