加氢换热器热电偶套管泄漏失效分析  

Failure Analysis on the Leaking of Thermocouple Thermowell for Heat Exchanger in Catalytic Reforming Unit

作　　者：何家胜[1] 危卫[1] 鲁录义[1] 朱晓明[2] 吴建平[2] 路远明[2] 

机构地区：[1]武汉工程大学机电工程学院,湖北武汉430074 [2]中国石油化工股份有限公司武汉分公司,湖北武汉430082

出　　处：《石油化工腐蚀与防护》2008年第2期62-64,共3页Corrosion & Protection In Petrochemical Industry

摘　　要：采用化学成分分析、金相分析、宏观与微观断口分析以及有限元分析等方法,对某石化厂重整车间加氢换热器热电偶套管接管处的泄漏原因进行了分析和研究。分析结果表明,由于接管材料的含碳量过高,在进行焊接加工时,焊接热影响区过饱和的碳从奥氏体中析出而形成碳化铬,碳化铬的形成使得很多晶界处成了极端贫铬区,这些区域在一定的介质条件下发生了晶间腐蚀,产生了微观孔洞。在工作压力的作用下。这些孔洞发生沿晶扩展,当这些孔洞相互连接、内外贯通后,就发生了泄漏。针对泄漏发生的原因,采取了相应的处理措施,抑制了换热器的腐蚀。The leaking behavior of thermocouple thermowell was studied by chemical composition analysis, metallographic analysis, microstructure analysis, and finite element analysis of the failure samples. The results show that because of the excessive carbon content in the material, the over- saturation carbon was liberated from the austenite while welding, and chrome carbide was formed, which caused the poor Cr zones along grain boundaries. Intergranular corrosion occurred under special conditions in these zones, resulting in some empty pores. Under the operation pressure, these pores were expanding along grain boundaries. When the inner and outer pores were connected, the leaking occurred.

关 键 词：奥氏体不锈钢 贫铬 有限元分析 

分 类 号：TH811[机械工程—仪器科学与技术] TG172[机械工程—精密仪器及机械]