摘要
腐蚀失效是当前奥氏体不锈钢管应用的重要难题之一。06Cr19Ni10不锈钢无缝管管道在运行时发生了点状腐蚀失效,本文通过对失效管道取样进行宏观观察、微观检测、化学成分分析、晶间腐蚀检测等一系列理化检验,以及对材料运行介质,如水pH值、氯离子进行检测,分析讨论了06Cr19Ni10奥氏体不锈钢腐蚀失效的原因。试验结果表明,流体管中的水pH值为7.9,呈中性,且管材的晶间腐蚀检验结果合格,排除了晶间腐蚀失效的可能;无缝管化学成分分析和金相检验中未见异常,排除了流体管原材料微观缺陷导致失效的可能。分析认为,流体管中水的氯离子含量为62.04μg/g,超出了压力试验时对水质的要求,加之淤泥堆积的影响,导致不锈钢管多处出现点腐蚀坑,点腐蚀坑逐渐扩展直至穿透整个不锈钢管壁厚,最终导致失效泄露。建议更换点腐蚀当量更高、耐点腐蚀性能更佳的316系列奥氏体不锈钢或奥氏体-铁素体双相钢无缝管。同时结合304系列材料的失效案例,对304系列材料的使用环境给出合理建议。
At present,the corrosion failure is one of important difficulties in application of austenitic stainless steel pipe.The 06Cr19Ni10 stainless steel seamless pipe pipeline experienced pitting corrosion failure during operation.The failed pipeline was sampled for physical and chemical inspections of defects,including macroscopic observation,microscopic examination,chemical composition analysis,and intergranular corrosion detection.The running medium such as water pH and chloride ion were also detected to analyze the cause of corrosion failure of 06Cr19Ni10 austenite stainless steel.The test results showed that the water in pipeline was at pH 7.9,which was neutral.Moreover,the intergranular corrosion test results of pipes were qualified,thus excluding the possibility of intergranular corrosion failure.The chemical composition analysis and metallographic examination of seamless pipe had no abnormality,which exclude the possibility of microdefect of fluid pipe raw material to cause failure.It was found that the chloride ion content in water within fluid pipe was 62.04μg/g,which exceeded the water quality requirement in pressure testing.Combining with the influence of silt accumulation,numerous pitting corrosion pits were caused on the stainless steel pipe.The pitting corrosion pits gradually expanded until they penetrated the entire thickness of stainless steel pipe wall,ultimately resulting in failure and leakage.It was recommended to replace with seamless pipe of 316 series austenitic stainless steel or austenitic-ferritic duplex steel,which had higher pitting corrosion equivalent and better pitting corrosion resistance.At the same time,based on the failure cases of 304 series materials,some reasonable suggestions were given for the usage environment of 304 series materials.
作者
余海燕
胡丛庆
陈雪杰
陈旭斌
曹昕明
YU Haiyan;HU Congqing;CHEN Xuejie;CHEN Xubin;CAO Xinming(Tsingshan Steel Pipe Co.,Ltd.,Lishui 323900,China)
出处
《物理测试》
2025年第4期45-49,共5页
Physics Examination and Testing
关键词
06Cr19Ni10不锈钢
无缝管
氯离子
点腐蚀
晶间腐蚀
06Cr19Nil0 stainless steel
seamless pipe
chloride ion
pitting corrosion
intergranular corrosion
