Oxidation behavior of Super304H and HR3C steels in high-temperature steam condition

The oxidation behaviors of Super304H and HR3C steels were investigated in high-temperature steam at 610°C/14 MPa for times ranging from 200 h to 2000 h. The oxidation microstructural features of Super304H and HR3C in the steam environment were characterized systematically. For Super304H, after 200 h steam oxidation, the specimen surfaces were corroded and covered with fine oxide particles. As time increased, spherical oxides grew on the relatively flat surface. These oxide particles continuously grew and thickened on the sample surfaces and gradually connected. After 2000 h steam oxidation, cross-sections exhibited typical duplex oxide layer structure. For HR3C, its oxygen diffusion was effectively mitigated by a dense, Cr-rich inner layer due to the high Cr content, which is the primary factor contributing to the stability in high-temperature steam environments. When analyzing the growth behavior of oxide layer, Super304H demonstrated excellent oxidation kinetics, with a faster oxidation rate and formed thicker oxide layers, compared to HR3C.