ANALYSIS ON THE CAUSES OF HIGH-TEMPERATURE CORROSION AND THE MEASURES FOR IT'S PROTECTION
YANG Hou-jun, LI Zheng-gang, LI Chao-zhi, LI Feng-cheng ( Central China Power Branch Corporations of State Power Co., Wuhan 430077,China; College of Power and Mechanical, Wuhan University, Wuhan 430072, China; Sanmenxia Huayang Power Plant, Sanmenxia 472143, China)
The reheater of No.2 boiler in Sanmenxia Power Plant is made of 12Cr2MoWVTiB steel. Corrosion on the surface of reheater tubes occurs during operation. Through chemical element analysis, mechnical performance test, metallographic analysis and electron probe element analysis, Failure reason of the tube have been analyzed. The result, shows that (he quality of those tubes is up to the standard. But there is a layer of obvious scaling on its exterior. Main element of the scale is sulfate beside oxide. Metallographic structure under oxide have some corrosional micro-crack. Element S exists in corrosional product along crystal grain boundary. Thus, it can be concluded that the type of corrosion is a high temperature sulphur corrosion, whose mechanism and reason are analyzed and preventive measures are proposed.
【CateGory Index】： TK224.9