仪表风冷却器换热管开裂失效原因分析

Cracking failure analysis of heat exchange tube in instrument air cooler

某炼化企业仪表风冷却器在运行中换热管发生了开裂失效,通过宏观形貌观察、微观形貌观察、能谱分析和金相组织分析等技术手段分析了该换热管发生开裂失效的原因,并提出了相应的解决方案。分析结果表明:该换热管材质为S31608奥氏体不锈钢,该换热管发生开裂的主要原因是氯化物应力腐蚀开裂,其次为温差应力较大引发的腐蚀疲劳开裂。为了解决该换热管的开裂失效问题,应确保工艺操作平稳,对换热器结构进行优化设计,换热管应选用超低碳不锈钢材质。

Cracks occurred on heat exchange tube of instrument air cooler in a refining enterprise.The causes were studied through technical means such as macroscopic morphology observation,microscopic morphology observation,energy spectrum analysis and metallographic structure analysis,relevant solutions were presented.The analysis results suggested that the material of heat exchange tube is made of S31608 austenitic stainless steel.The main reason for cracking of heat exchange tube is chloride stress corrosion cracking,and followed by corrosion fatigue cracking aroused by large temperature difference stress.Thus,it is necessary to ensure the smooth process operation,optimize the design of heat exchanger structure and select ultra-low carbon stainless steel as the material of heat exchange tube.