某超临界锅炉低温再热器管腐蚀原因分析

Corrosion Analysis of Low Temperature Reheater in a Supercritical Boiler

针对某超临界锅炉低温再热器管存在大量表面腐蚀的情况,采用金相显微镜、扫描电子显微镜、能谱分析和X射线衍射等材料学分析手段,对此低温再热器管腐蚀产物进行了分析,并结合锅炉现场的实际运行情况,给出了该低温再热器管腐蚀产生的原因。结果表明:该低温再热器腐蚀的主要原因是表面防锈层脱落导致基体金属的氧化腐蚀,超温加速了腐蚀进程;该低温再热器管材料组织存在老化现象、力学性能已低于标准要求。

For the surface corrosion of low temperature reheater tubes in a supercritical boiler,corrosion causes of the low-temperature reheater tubes were analyzed,using optical microscopy,scanning electron microscopy,spectroscopy,X-ray diffraction analysis and so on. The results showed that the low temperature reheater corrosion is mainly due to rust protection layer exfoliation leading to oxide corrosion of the base metal. Overtemperature accelerates the corrosion process. Microstructure of low temperature reheater tubes is aging,and the mechanical properties are lower than thestandard