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通过对某电厂TP347H不锈钢管的过热器和再热器管样内壁氧化皮及其剥落物进行金相检验、扫描电镜观察、能谱分析、X衍射等分析,研究锅炉用奥氏体不锈钢管蒸汽侧氧化皮的形态及其形成规律。结果表明:根据氧元素分布规律、Fe-Cr-Ni元素由基体向外扩散传质及水蒸汽中H、O由氧化层向内扩散传质原理,该不锈钢蒸汽侧氧化皮分为内、中、外3层,内层为致密的(Cr,Fe)2O4、NiO等非均质层,中间层为疏松的粗大柱状结构的Fe3O4,最外层为厚度较薄的Fe2O3;内层/中间柱状氧化层界面存在离解后的细小的氧化物颗粒,使界面粘附强度低,组织疏松,从而使中间柱状氧化层更易剥落,该类奥氏体不锈钢蒸汽侧氧化皮剥落物主要是以外两层片状氧化皮为主。
Through the metallographic examination, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis on the oxide scale and its exfoliation of the superheater and reheater tubes in a power plant TP347H stainless steel tube, the effects of the austenitic stainless steel tube steam The morphology of the side scale and its formation. The results show that according to the rule of oxygen distribution, the diffusion and mass transfer of Fe-Cr-Ni element from the matrix and the inward diffusion and mass transfer of H and O in the water vapor by the oxide layer are divided into inner and outer , The outer three layers, the inner layer is dense (Cr, Fe) 2O4, NiO and other non-homogeneous layer, the middle layer is loose loose large columnar structure Fe3O4, the outermost layer is thinner Fe2O3; inner layer / middle columnar Oxide layer interface exists after the dissociation of small oxide particles, the interface adhesion strength is low, the organization loose, so that the middle of the columnar oxide layer easier to peel, the class of austenitic stainless steel steam side oxide flake is mainly the outer two-layer film Oxide-based.