超临界机组国产和进口T23炉管服役30000h后氧化膜、基材组成及性能对比

Comparison of Composition and Performance of Oxide Films and Substrates of Domestic and Imported T23 Steel Furnace Tubes in Supercritical Unit after 30000 h of Service

为促进T23耐热钢的改性和国产化应用,利用SEM和EDS对某电厂同参数条件下超临界机组服役30 000 h后的进口锅炉和国产锅炉T23管末级过热器和末级再热器基体及氧化膜进行了表面和截面形貌及成分对比分析。结果表明,国产和进口锅炉T23管低温时水蒸汽侧氧化物颗粒较高温时粗大,但进口T23管氧化物颗粒没有明显裂纹且氧化内腐蚀较轻微;国产和进口T23钢运行过程中限制氧化进一步发生的是O元素;进口管氧化膜有明显的等轴晶富Cr保护层。

The surface and cross-section morphology and composition of the T23 steel tubes,installed in the final stage superheater and final reheater of imported boiler and domestic boiler of the supercritical unit,after 30 000 h of service under the same parameters,were analyzed with a scanning electron microscope and an energy dispersive spectrometer. Besides,the morphology and composition of the oxide films formed on the tube surfaces after 30 000 h of running were also analyzed. Results showed that the oxide particulates on the steam side of both imported boiler and domestic boiler at low temperature were lager than those at high temperature. As compared with the oxide particulates on domestic T23 tube,those on the imported T23 tube showed no obvious crack and slight oxidation internal corrosion. Besides,element O was able to retard further oxidation of the imported and domestic T23 tubes during running; and in particular,isometric Cr-rich cover was present in the oxide film of the imported T23 tube.