High temperature oxidation behavior and roll stricking mechanism of ferritic stainless steel

Behavior of high temperature oxidation of medium chromium ferrite stainless steel was studied by thermal gravimetric analysis (TGA). From oxidation curves, the oxidation mass gain per unit area with time was in parabolic relation. The compact oxidation hindered ion diffusion under the selective oxidation of chromium, and the activation energy of medium chromium ferrite stainless steel was 560 kJ/mol. From the observation of the surface morphology of oxide scale, Fe-Cr spinel was found on the surface of oxide scale, and the Fe-Cr spinel increased as temperature increased. When oxidation temperature reached 1100 , the morphology of the oxide scale was layer structure, FeO and Fe3O4developed at outermost layer, under which the Fe-Cr spinel developed. The sticking experiment proved that Fe-Cr spinel would make the cracks on the surface of roller which formed in the protess of cycling rolling and cooling. Fe-Cr spinel promoted the formation and propagation of cracks, and provided the nucleation sites for sticking. The oxide scale has a protective effect on the surface quality of the slab during hot deformation, decreasing the sticking phenomenon. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.