Evaluation of inclusion agglomeration behavior in molten steel based on the modified model of cavity bridge force

Abstract

Inclusion agglomeration behavior in molten steel is a key factor that affecting steelmaking process and steel quality. In this work, the modification on the Laplace pressure of cavitation interaction between inclusions has been made according to the calculation model of cavity bridge force. The effects of the distance between inclusions, the diameter of inclusions, the surface tension of molten steel, and the contact angle between inclusions and molten steel on the cavity bridge force were quantitatively investigated by using this modified model. The results show that the contact angle between inclusions and molten steel has a significant influence on inclusions agglomeration. The inclusions cannot agglomerate by cavity bridge force when the contact angle is less than 90°. Subsequently, the agglomeration tendency of different inclusions was calculated and compared. The order of cavity bridge force and critical agglomeration distance of inclusions in molten steel is MgO·Al2O3 < CaO < MgO < Ti2O3 < AlN < Al2O3. Then the high temperature experiments were carried out to investigate the evolution of inclusions sizes in molten steel. It is found that the average size of Al2O3 is larger than that of AlN, which indicates that the agglomeration tendency of AlN inclusions is much weaker than that of Al2O3 inclusions. This calculation model can accurately evaluate the agglomeration behavior of inclusions and provide theoretical guidance for inclusions control.