In-Situ Observation of the Modification Behavior of Alumina Inclusions in a Calcium-treated Steel

In the current study, a novel laboratory experiment and a kinetic calculation were proposed to analyze the modification behavior of alumina inclusions in the molten steel. To obtain the shape and composition of a single Al₂O₃ inclusion at different times during the modification process, confocal scanning laser microscopy experiments were conducted to track the evolution of the Al₂O₃ inclusion particle on the surface of Ca-treated steel. Then, the composition evolution of the Al₂O₃ inclusion particle during the modification process was predicted using a kinetic model. It was assumed the product layer was homogeneous. The diffusion of dissolved [Ca], [Al], and [O] crosses through the inclusion-steel interface was considered. Experimental results agreed well with kinetic calculated results. Meanwhile, the kinetic model was used to analyze the modification behavior of Al₂O₃ inclusions in steel with various influence factors including the [Ca] content in steel, the [Al] content in steel, and the initial size of inclusions.