Effect of Interfacial Properties on Agglomeration of Inclusions in Molten Steels

摘要

Contact angles of five common grades of molten steel on Al_2O_3, MgO and MgO·Al_2O_3 inclusion substrates have been measured precisely by a sessile drop technique at 1 823/1 873 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 Al_2O_3 > MgO > MgO·Al_2O_3, and the relationship between coagulation coefficient α_t of inclusions and contact angle θ between inclusions and molten steels can be expressed as α_t = 4.923x10~(-5)[μr_1~3(ρ_Mε/μ)~(1/2)/(σ_1-σ_Mcosθ)]~(-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.