埋地燃气管道腐蚀失效原因分析  

Failure cause analysis of buried gas pipeline corrosion

作　　者：徐彩军 杨文彬 王芳 黄耀波 刘爱国 蔡文昕 李言伟 XU Caijun;YANG Wenbin;WANG Fang;HUANG Yaobo;LIU Aiguo;CAI Wenxin;LI Yanwei(Fujian Boiler Pressure Vessel Inspection Research Institute,Fuzhou 350008,China)

机构地区：[1]福建省锅炉压力容器检验研究院,福建福州350008

出　　处：《兵器材料科学与工程》2024年第5期156-161,共6页Ordnance Material Science and Engineering

基　　金：福建省锅检院自立项目(FJGJ2023002)。

摘　　要：针对埋地燃气管道在巡线过程中出现的泄漏情况,开挖后发现管道表面有局部腐蚀坑。通过外防腐层检查、宏观检查、壁厚测量、化学成分分析、力学性能检验、金相组织分析、腐蚀产物分析、腐蚀环境调查等,系统研究了该埋地燃气管道失效的原因及机制。结果表明:由于外防腐层破损,管道长期与腐蚀性较弱的土壤接触而发生局部穿孔;在较高含水量、较高氧化还原电位、较低含盐量、含氯离子的碱性土壤中发生了吸氧腐蚀和硫酸盐还原菌腐蚀;且在Cl-等阴离子侵蚀下,腐蚀产物膜被破坏,形成蚀孔内金属为小阳极-蚀孔外金属为大阴极的微电偶腐蚀电池,加速了向管体内壁的腐蚀进程。According to the leakage of buried gas pipeline during the inspection process,local corrosion pits were found on the surface of the pipeline after excavation.The reason and mechanism of the failure of the buried gas pipeline were systematically studied through the inspection of the outer anticorrosive layer,macroscopic inspection,wall thickness measurement,chemical composition analysis,mechanical property inspection,metallographic structure analysis,corrosion product analysis and corrosion environment investigation.The results show that due to the damage of the outer anticorrosive layer,the local perforation occurs when the pipeline is in contact with the less corrosive soil for a long time.Oxygen absorption corrosion and sulfate reducing bacteria corrosion occurred in alkaline soil with higher water content,higher redox potential,lower salt content and chloride ion.Moreover,under the attack of anions such as Cl-,the corrosion product film is destroyed,forming a micro-galvanic corrosion battery with a small anode inside the corrosion hole and a large cathode outside the corrosion hole,which accelerates the corrosion process towards the inner wall of the tube.

关 键 词：埋地燃气管道 吸氧腐蚀 硫酸盐还原菌腐蚀 Cl- 失效分析 

分 类 号：TG172.4[金属学及工艺—金属表面处理] TE832[金属学及工艺—金属学]