采用扫描电镜、能谱仪、X射线衍射仪等研究了T23钢管蒸汽侧氧化层的结构和形成机理。结果表明: 该氧化层分为内层、中间层和外层;内层为疏松及富含孔洞的富铬、钒及钨的非均质层氧化层, 中间层为相对致密且呈柱状结构的Fe3O4, 外层为较薄的Fe2O3;金属基体与内层氧化层界面处存在内氧化, 金属基体与内层氧化层界面处存在明显界限及间隙, 温度剧烈变化时氧化层易在金属基体与内氧化层界面处剥落;T23钢蒸汽侧内层氧化层疏松、多孔及其整体易剥落的特征, 使其抗蒸汽氧化性能差。

The oxidation mechanism and characteristics of steam-side oxide scales formed on the internal surface of reheater tubes made of T23 steel were investigated by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the oxide scale consisted of three layers: the inner layer was loose and porous heterosphere oxides containing Cr, V and W;the middle layer was the compact Fe3O4 with the columnar crystal microstructure;the outer layer was a relatively thin layer of Fe2O3. There was internal oxidation occurring in the interface between alloy matrix and inner oxide scale, and in the interface there were obvious bounds and small gaps, which made the oxides easily flake off during great temperature variation. The steam-side oxide characteristics, including the loose and porous inner layer and easy flaking off of whole oxides, decreased the anti-steam oxidation performance of T23 steel.