Effect of oxygen and sulfur on alumina particle behavior in front of solid–liquid interface of steel liquid

In this work, the interface characteristics between alumina and the steel liquid with different sulfur and oxygen concentrations were measured by an improved sessile drop method. And the behavior of alumina inclusions in front of the solid-liquid interface of steel liquid with different oxygen and sulfur concentrations was investigated by in-situ observation. Furthermore, the behavior of alumina particles in front of the solid-liquid interface on the surface of the steel liquid was discussed from the interface characteristics between alumina and the steel liquid with different sulfur and oxygen concentrations based on the interface gradient force, coulombic force, and Marangoni effect viewpoints. The results show that the large and small inclusion particles were engulfed and pushed, respectively, at the interface of solid-liquid, while the critical average radius for engulfed inclusion particles decreased from 7.73 μm to 6.21 μm and 4.84 μm, respectively, with sulfur and oxygen concentrations increasing. And the behavior can be described by a function formula concerning the interface characteristics between alumina and the steel liquid with the different sulfur and oxygen concentrations based on the interface gradient force, coulombic force, and Marangoni effect viewpoints. Further, it is found that the aggregation ability due to capillary force is weakened and even dispersed at the solid-liquid interface, which leads to the inclusion being easily pushed away from the front of the solid-liquid interface with the increase in sulfur and oxygen concentrations.