2019 Volume 59 Issue 10 Pages 1735-1743
Contact angles of five common grades of molten steel on Al2O3, MgO and MgO·Al2O3 inclusion substrates have been measured precisely by a sessile drop technique at 1823/1873 K, and the wettability of each type of inclusions is discussed. Interfacial tension between the steels and the inclusions is calculated through the Young equation. Thus, coagulation coefficient, which is used to evaluate agglomeration tendency of inclusions, has been calculated based on the collision-coagulation theory combined with the interfacial tension data. The results of the coagulation coefficient show that the agglomeration tendency of the three typical oxide inclusions in molten steel is Al2O3 > MgO > MgO·Al2O3, and the relationship between coagulation coefficient αt of inclusions and contact angle θ between inclusions and molten steels can be expressed as αt = 4.923 × 10−5[μrI3(ρMε / μ)1/2 / (σI – σMcosθ)]−0.242. Furthermore, in order to verify the validity of the results obtained, three deoxidation experiments in resistance furnace were carried out. The resulting samples were quenched and then analyzed by SEM-EDS and ASPEX. The results of inclusions observed in the quenched samples show good agreement with the results of inclusion agglomeration tendency. Overall, the effects of wettability and interfacial tension on inclusion agglomeration behaviors are proved to be remarkable.