Effect of Acid Slag Treatment on the Inclusions in GCr15 Bearing Steel

Abstract

By laboratory slag/steel reaction equilibrim experiments, the viriation of oxygen content, inclusion compositions and inclusion sizes were studied. The effect of acid slag treatment on the transition mechanisms of D-type inclusions and the precipitation of TiN inclusions in GCr15 bearing steel were explored. The obtained results showed that the dominant inclusions in steel were plastic and smaller Al2O3-SiO2-MnO. The melting point were lower than 1400°C treated by the acid refining slag of 35.1%CaO-15%Al2O3-43.9%SiO2-6%MgO and there was no TiN found. The evolution of MgO·Al2O3 inclusions is: MgO·Al2O3→ MgO·Al2O3·SiO2·MnO→ Al2O3·SiO2·MnO. Mg and Al from MgO·Al2O3 inclusions were displaced by [Si] and [Mn] in steel liquid , and formation of plastic Al2O3-SiO2-MnO inclusions finally, whose compositions distribution were uniform. Mg and Si, Mn were complementary in inclusions as to the spatial distribution.

Keywords

• acid slag
• inclusion type
• gcr15 bearing steel