Effect of Pre-Oxidation on the Steam Oxidation of Heat-Resistant Steel T92

Effect of pre-oxidation on the steam oxidation of T92 heat-resistant steel at 650 degrees C was investigated. The results show that the mass gain and the oxide thickness of T92 sample with pre-oxidation treatment were lower than that of T92 sample after exposure in steam at 650 degrees C. The compact and discrete Cr-rich oxide which formed on the pre-oxidized specimen hindered ion diffusion, leading to the lower oxidation rate. The effect of pre-oxidation worked at the initial stage due to the protective Cr-rich layer formed in air gas. After a long time exposure in steam, the pre-oxidation influence decreased slowly and eventually disappeared. What's more, the adhesion property of oxide scale was improved by pre-oxidation.