长期服役锅炉末级再热器管泄漏分析  

Analysis on the Leakage of Final-stage Reheater Tube in a Boiler with Long-term Service

作　　者：柏振峰 Bai Zhenfeng(Shanghai Wujing No.2 Power Generation Co.,Ltd.,Shanghai 201109,China)

机构地区：[1]上海吴泾第二发电有限责任公司,上海201109

出　　处：《发电设备》2024年第1期62-66,共5页Power Equipment

摘　　要：某电厂600 MW亚临界机组累计运行14万h后,锅炉末级再热器管发生泄漏。通过宏观观察、金相分析、扫描式电子显微镜(SEM)观察、能谱分析、X射线衍射(XRD)分析、硬度测试、拉伸性能测试等方式,对发生泄漏的末级再热器12Cr1MoV钢管段进行分析。结果表明:发生泄漏的进汽侧12Cr1MoV钢管段已发生明显的组织老化,球化等级为4级,布氏硬度降低至103HBW,屈服强度低于标准值。机组长期运行过程中再热器管内壁的氧化皮发生脱落,使U形弯管的下弯头部位堵塞,从而导致进汽侧直管段发生严重超温。12Cr1MoV材质发生组织老化和性能下降,管内壁氧化皮脱落严重导致壁厚减薄,从而引起爆管泄漏。For a 600 MW subcritical unit with the operation time of 140 ooo hours in a power plant,the leakage of the final-stage reheater tube in the boiler occurred.By means of macroscopic observation,metallographic analysis,scanning electron microscope(SEM)observation,energy dispersive spectrometer analysis,X-ray diffraction(XRD)analysis,hardness test and tensile property test,analyses were conducted on the leaked 12CrlMoV steel tubes in the final-stage reheater.Results show that the leaked 12CrlMoV steel tube has the obvious microstructure aging with the spheroidization grade of 4.Meanwhile,Brinell hardness is decreased to 103HBW,and the yield strength is lower than the standard value.The blockage of the lower elbow of U-shape tube is resulted from the peeling oxide layer from the inner wall of reheater tube in the unit with long-term service,which leads to the serious overtemperature of the straight section in steam admission side.The leakage and burst of tube would occur with the comprehensive effect of the microstructure aging and property degradation of 12CrlMoV material,and the thinner tube wall caused by the peeling of a large amount of oxide layer.

关 键 词：锅炉 末级再热器 泄漏 12CR1MOV钢 组织老化 

分 类 号：TK228[动力工程及工程热物理—动力机械及工程]