Steam Oxidation Resistant Protective Layer on Ferritic Steels Formed by Heavy Deformation and Pre-Oxidation Treatment

The steam oxidation behavior of Mod. 9Cr-1Mo ferritic steel, which was pre-oxidized in air after heavy compressive deformation, was studied. This procedure provided a Cr2O3-type thin oxide layer, which has oxidation protectiveness in high temperature steam atmosphere. The protectiveness of such oxide layer, however, depended on the magnitude of deformation. The thin protective layer which formed on the severely deformed region maintained during the test period of up to 1.44 Ms in steam at 650°C, while thick oxide scale grew on the region provided with less deformation.