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

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%approximate to 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%approximate to 70% for these oxide cores. Increasing TiO2 content in slag increases log(aAl2O3/aMgO3), which in turn decreases Mg content in the steel. This decreases MgO content in MgO-Al2O3-TiOx type inclusions.

Automated summary

This study investigates the influence of TiO2 in ladle slag on inclusions in liquid steel. Experimental results show the presence of various types of inclusions in the steel samples, which are affected by the MgO and Ti content in the liquid steel and the composition of the slag.