某20钢燃气钢管埋地使用不到一年的时间里先后多次发生腐蚀穿孔失效, 通过宏观检验、化学成分分析、金相检验、扫描电镜分析等方法对钢管腐蚀穿孔原因进行了分析。结果表明: 燃气钢管穿孔的孔洞由外向内扩展, 其外观形貌具有杂散电流腐蚀的特征, 同时由于钢管内部存在大量的非金属夹杂物, 引起内壁点腐蚀的发生, 出现大量腐蚀坑; 燃气钢管的腐蚀穿孔主要是由于土壤中的杂散电流造成的。

Corrosion perforation failure happened for many times to 20 steel gas pipelines in less than a year after being buried, and the corrosion reasons were systematically analyzed by macroscopic examination, chemical compositions analysis, metallographic examination and scanning electron microscopy analysis. The results show that the corrosion holes of the gas steel pipelines extended from outer wall to inner wall and had characteristics of stray current corrosion. Meanwhile, the inner wall of the gas steel pipeline appeared plenty of corrosion pits because there were a large number of inclusions, which caused the pitting corrosion. The corrosion perforation of the gas steel pipelines was mainly due to the stray current in the soil.