The Effect of TiO2 in the Ladle Slag on Inclusion in Ti‐Bearing Steel

Abstract

To improve the castability of Ti‐bearing steel, the knowledge of inclusions formed in liquid steel, affected by the slag composition, must be obtained. In this study, the effect of TiO2 in ladle slag on inclusions in this steel at 1873 K is investigated. Experimental results indicate that Ca–Mg–Al–Ti–O complex inclusions, complex TiN inclusions containing MgO–Al2O3–TiOx cores, Ti–C–S inclusions, and TiC inclusions appear in the steel samples. The cores in TiN inclusions are mainly in the liquid and liquid + spinel fields before slag addition. When the steel reacts with slag containing 0% TiO2 for 1 h, the inclusions in the steel are mostly in the MgO + liquid + spinel and MgO + liquid field and have the highest MgO content. When the steel reacts with slag containing 5%≈20% TiO2 for 1 h, most inclusions are liquid slag + spinel and liquid slag phases. The average liquid fraction in most inclusions is higher than 60%. The ratio of the (mass percentages Ti3+) to (Ti3++mass Ti4+) in most liquid phases is approximately 50%≈70% for these oxide cores. Increasing TiO2 content in slag increases log(), which in turn decreases Mg content in the steel. This decreases MgO content in MgO–Al2O3–TiOx type inclusions.