Reaction mechanism between Al₂O₃–MgO refractory materials and rare earth high-carbon heavy rail steel

Submerged entry nozzle (SEN) clogging is a major problem affecting the production quality of rare earth steel, and finding a suitable refractory outlet can significantly reduce production costs. To explore the relationship between refractory composition and interface interaction, unprotected coated Al₂O₃–MgO refractories and SiO₂-coated Al₂O₃–MgO refractories were added to rare earth high-carbon heavy rail steel under laboratory conditions, and the Al₂O₃–MgO refractory was found to be more suitable. The results show that, from the epoxy resin side to the refractory side, the contour of the refractory interface reaction layer can be divided into two main layers: an iron-rich reaction layer and an iron-poor reaction layer. Calculations based on the spherical model suggest that the adhesion force is proportional to the size of the refractory particles and inclusions, and the same result applies to the surface tension. Controlling the inclusions at a smaller size has a specific effect on alleviating the erosion of refractories. Combined with the erosion mechanism of Al₂O₃–MgO refractories, the interface reaction mechanism between Al₂O₃–MgO refractories and molten steel was proposed, which provides ideas for solving SEN clogging.