摘要
利用宏观检查、金相检验、电镜观察、能谱分析和X射线衍射仪等方法,对某热电厂过热器和再热器管内壁氧化皮的化学成分和组织结构进行了试验研究,探讨了STBA24钢高温蒸汽氧化的微观特征和氧化机理.结果表明:STBA24钢管在运行中,当管壁温度超过材料的许用温度时,易发生高温水蒸汽氧化;腐蚀产物分内外2层,外层以Fe2O3、Fe3O4为主,易剥落,内层为致密的保护性氧化物,具有长期抗氧化能力.金属材料的蒸汽氧化和剥落会增大管壁应力,造成管壁破裂或爆管.
Chemical composition and microstructure of oxide scales on inner surface of STBA24 reheater and superheater tubes in a certain thermal power plant were studied systematically using macro,metallographic,scanning electron microscope（SEM）,energy dispersive spectrum（EDS） and X-ray diffractometer（XRD） method,so as to find the microstructure features and formation mechanism of the steam oxidation scales.Results show that high-temperature steam oxidation will occur if actual working temperature of tube wall exceeds its allowable value during service period of STBA24 steel tubes.The oxidation scale can be divided into 2 layers： the outer layer is mainly made up of Fe_2O_3 and Fe_3O_4,easy to exfoliate,while the sublayer consists of a dense oxide film,with strong resistance to steam oxidation.Steam oxidation and oxide scale exfoliation may raise the stress of tube wall and result in tube burst failures.
出处
《动力工程学报》
CAS
CSCD
北大核心
2010年第4期293-297,303,共6页
Journal of Chinese Society of Power Engineering
基金
国家“十一五”科技支撑计划课题资助项目(2006BAK02B03)
关键词
STBA24钢
过热器管
再热器管
高温蒸汽氧化
微观特征
STBA24 steel
superheater tube
reheater tube
high-temperature steam oxidation
microstructure
