An Experimental Study on the Impact of Deoxidation Methods on the Fatigue Properties of Bearing Steels

Strong deoxidation and weak deoxidation are two kinds of deoxidation methods frequently applied in steelmaking. In the present study, high-carbon chromium bearing steels are smelted with a strong deoxidizer and a weak deoxidizer, respectively in industrial trials. The generation mechanism of inclusions is analyzed, and the inclusion stability diagrams of the Fe–Si–Al–Mg–Mn–O system at 1873 and 1843 K are calculated. The very high cycle fatigue life of bearing steels deoxidized with different deoxidizers is also experimentally compared. The results showed that the evolution routes of inclusion in high-carbon chromium bearing steels deoxidized by Si and Al are CaO–Al₂O₃–SiO₂ → CaO–Al₂O₃–SiO₂–MgO and Al₂O₃ → CaO–Al₂O₃–SiO₂–MgO, respectively. The Al content in steel is controlled by different methods when different deoxidizers are applied. The effect of the oxide inclusions generated during Si deoxidization on the fatigue life is lower than that during Al deoxidization, even if the total oxygen content is slightly higher. This effect suggests that it is not accurate to evaluate the fatigue life of steels with the total oxygen content, and it is also desirable to produce bearing steels with the Si deoxidation method.