Effect of Al–Ti Concentration on Alumina Inclusions Aggregation Floating Behavior in Molten IF Steel

Abstract

Understanding the aggregation‐floating behavior of alumina inclusions, which is influenced by the interface properties between inclusions and molten steel, is crucial to control the purity of interstitial‐free (IF) steel in the refining process. In this work, it is attempted to investigate the effect of aluminum and titanium concentrations on the aggregation‐floating behavior of alumina inclusions in the interior of IF molten steel based on the interface properties between molten steel and alumina inclusions. The interface properties between the molten steel and alumina inclusions are measured using an improved sessile drop method. And, the aggregation‐floating behavior of inclusions in the interior of molten steel is quantitatively discussed by an aggregation model based on the attractive force between alumina inclusions, which was combined with the interface properties. In the results, it is shown that the attractive forces between alumina inclusions, ranging from 6.96 × 10−6 to 5.41 × 10−5 N, increase and decrease, respectively, with increasing aluminum and titanium concentrations. Furthermore, the terminal floating speeds of alumina inclusions, ranging from 0.0510 to 0.0873 m s−1, increase and decrease, respectively, with increasing aluminum and titanium concentrations.