Using a facility of simulation steam oxidation experiment bench at 650 ℃, steam oxidation test up to 1 000 h was carried out for 4 domestic S30432 steels. Morphology, composition and phase structure of oxide layers formed on inner surface of S30432 steel tubes during oxidation at 650 ℃ were investigated systematically by means of scanning electron microscope (SEM), energy dispersive X-ray spectroscope ( EDX ) and X-ray diffractometer ( XRD), so as to observe the characteristics of the steam oxidation scales. The result shows that the smaller and the more uniform the grain sizes are, the greater the steam oxidation resistance is. Shot blasting facilitates an increased diffusion of Cr and forms a dense and protective Cr-rich oxide layer, result in an enhanced resistance to steam oxidation. Therefore, the grain size of S30432 steel tubes and the difference in grain size could be controlled strictly by domestic manufacturers or using surface technology to improve the steam oxidation resistance.%在实验室条件下对4种国产S30432钢管试样进行了 650℃下、不同时间的模拟蒸汽氧化试验,然后借助光学显微镜、扫描电镜、能谱分析仪和X射线衍射仪等分析设备对氧化试验后的试样内壁氧化层的形貌、成分和相组成进行了对比研究.结果表明:提高管样晶粒度级别及其均匀性有利于改善抗蒸汽氧化性能；管样内壁表面经喷丸处理,有利于形成致密高Cr的氧化层,显著提高抗蒸汽氧化性能.因而,可采用提高不锈钢管的晶粒度的均匀性或者采用表面技术来改善不锈钢的抗蒸汽氧化能力.
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