Inclusions Absorbed by Slags in Interstitial-Free Steel Production

The nonmetallic inclusions absorbed by ladle slags during secondary steelmaking operations and in the tundish and mold during casting are crucial to the production of interstitial-free (IF) steel. However, little to no research has been conducted on the separation and dissolution of inclusions along with a focus on IF steel. Herein, a theoretical study of the separation of solid alumina at the steel-slag interface is conducted. The dissolution of alumina particles is observed in situ in different IF steel slags, and the dissolution mechanism is analyzed. The results show that the interfacial tensions and slag viscosity have a large influence on the predicted displacement, but for IF steel production, the dissolution of inclusions in the slags has a greater influence on the removal of inclusions than on inclusion separation. Using ladle slags with a proper CaO wt%/Al2O3 wt% is the most effective way to remove the Al2O3 inclusions compared with the other slags in IF steel production.