蒸汽过热器换热管爆管失效原因分析

Analysis of Burst Failure of Heat Transfer Tube of Steam Super-Heater

针对某企业蒸汽过热器12Cr1MoVG钢换热管在服役过程中出现的爆裂失效现象,采用光学显微镜、扫描电子显微镜(SEM)、能量色散谱(EDS)对12Cr1MoVG钢管基体低倍组织观察、非金属夹杂物分析、显微组织观察和晶粒度评级,分析了钢管表面腐蚀产物层显微组织及成分,结合断口表面形貌和裂纹前沿腐蚀产物进行成分分析,指出烟气侧S元素造成的高温硫腐蚀是导致蒸汽过热器爆管的主要原因。另外,换热管显微组织中出现黄块状组织,导致换热管力学性能下降,是蒸汽过热器爆管的次要原因。

For the burst failure of 12Cr1 MoVG steel heat transfer of the steam super-heater in service,optical microscope,scanning electron microscope（SEM）,energy dispersive spectroscopy（EDS）are used to observe the 12 Cr1 MoVG steel matrix macrostructure and microstructure,analyze the non-metallic inclusion and rate grain size.This paper analyzes the microstructure and composition of the corrosion product layer on the surface of the steel pipe.According to the fracture surface shape and component analysis of the corrosion crack front,it also points out that the high temperature corrosion caused by the element of S on the flue gas side is mainly responsible for the burst of steam superheater tube.In addition,the secondary cause is that the yellow block tissue appearing in the microstructure of heat transfer tube leads to the degradation of mechanical properties.