加热炉奥氏体不锈钢盘管的失效原因分析

Analysis on Failure Causes of Austenitic Stainless Steel Coiler in Heater

某输送含CO2天然气的再生气加热炉盘管在运行49 h后出现了开裂泄漏。通过渗透检测、材料理化性能测试、晶间腐蚀试验、扫描电镜断口形貌分析、能谱分析,结合实际运行的工况环境对盘管的失效原因进行了综合分析。分析结果表明:加热炉的原始设计资料考虑的使用环境未提及氯离子,而实际进入加热炉盘管的湿气介质中含有较高浓度的氯离子,盘管材质的理化性能分析未发现材料质量问题,盘管断口特征具备典型的脆性开裂特征,结合高温、高氯离子的使用特点,推断出氯化物应力腐蚀开裂是造成奥氏体不锈钢盘管开裂破坏的主要原因,从材料选择和腐蚀环境控制两个方面提出了相应的防护措施建议。

Cracking and leakage occur in the surface of stainless steel coiler in regeneration gas heater after operation for 49 hours in certain CO2 gas field.Conducted are liquid penetration inspection,physical and chemical performance test,intergranular corrosion test,scanning electron microscopy(SEM) fracture morphology analysis,energy spectrum analysis,and comprehensively analyzed are failure causes of the coiler in combination with actual operating conditions.It is found in test and analysis that no chloride ion is considered in original design information of the heater,however,chloride ion with high concentration exists in wet feed gas into the coiler and it is found in physical and chemical performance analysis that the coiler material quality meets requirements specified in relevant standards and coiler fracture has typical brittle cracking characteristics.According to characteristics of coiler operating in high temperature and high concentration chloride ion conditions,deduced is the conclusion that chloride stress corrosion cracking is the main reason resulting in Austenitic stainless steel coil cracking and destruction and corresponding protection measures are put forward from such two aspects as material selection and corrosion environment control.