埋地不锈钢管道氯离子应力腐蚀开裂分析与防治

Analysis and Prevention of Chloride Stress Corrosion Cracking of Buried Stainless Steel Pipeline

以某电厂埋地奥氏体不锈钢燃气管道90°弯头为研究对象,对其进行无损检测、理化检验、敷设环境分析等,分析外表面裂纹形成的机理。分析结果表明,该弯头为两顶管工程接驳部位,拘束应力大,且防腐层存在破损点,导致高浓度的氯离子与06Cr17Ni12Mo2的不锈钢弯头直接接触等因素,致使该弯头发生氯离子应力腐蚀开裂。最后,制定有效措施预防运行中的埋地奥氏体不锈钢管道类似安全隐患的产生。

Taking 90°elbow of buried austenitic stainless steel gas pipeline in a power plant as the research object,nondestructive testing,physical and chemical testing,soil composition analysis and other inspection items were carried out to analyze the mechanism of outer surface crack formation.The analysis results show that the elbow is the connection part of two pipe roof engineering,the constraint stress is large,and the corrosion protection layer has damage points,resulting in high concentration of chloride ion and 06Cr17Ni12Mo2 stainless steel elbow direct contact and other factors,resulting in chloride ion stress corrosion cracking of the elbow.Finally,formulate effective measures were made to prevent similar safety hazards in the operation of buried austenitic stainless steel pipeline.