Oxidation Behavior of High-Speed Steel Used for Hot Rolls

Non-isothermal oxidation kinetics of the high-speed steel (HSS) were studied by thermal gravimetric analysis. The surface and cross-sectional morphology of the HSS oxide film formed at different temperatures and durations were observed by scanning electron microscopy, and the corresponding chemical composition was analyzed by using energy dispersive spectrometer. The composition and structure of the oxide film were also investigated by X-ray diffraction. The results showed that the oxide scale of the HSS is mainly composed of Fe2O3, Fe3O4 and FeCr2O4. Temperature is the main factor on the quality of the oxide film. Below 600 °C, the oxidation rate of the steel is slow and the thickness of the oxide film is below 5 µm. However, the oxidation rate sharply increased as the temperature reaches 600 °C. Cr, Mo and V tend to concentrate at the scale/steel interface and form FeCr2O4 and other oxides.