Dynamic interaction between refractory and low-carbon low-silicon Al-killed steel

Abstract

To investigate the dynamic interaction between refining refractory and low-carbon low-silicon Al-killed steel, the “refractory-molten steel-inclusion” system was analyzed using dynamic erosion experiments and the FactSage database. This study discussed the formation of interfacial layers between various refining refractories and molten steel, as well as the transformation of nonmetallic inclusions in steel. The findings indicate that the interaction between refractories and molten steel produces a distinct interface layer. The influence of various refining refractories on inclusions varies significantly. MgO-C refractory promotes the formation of MgO·Al₂O₃ inclusions in steel, while Al₂O₃-MgO refractory leads to the formation of SiO₂-MnO-Al₂O₃ inclusions. Both Al₂O₃-SiC refractory and Al₂O₃-MgO-C refractory result in Al₂O₃ inclusions with trace levels of MgO. Steel refined with Al₂O₃-MgO-C refractory has increased MgO content within Al₂O₃ inclusions but still does not reach the stoichiometric ratio of MgO·Al₂O₃. As the initial Al content increases, the influence of MgO-C refractory inclusions becomes increasingly noticeable. The average MgO content within the inclusions rises with the reaction duration, achieving as high as 62.9%. The transition path of Al₂O₃ inclusions in molten steel follows “Al₂O₃→MgO·Al₂O₃→MgO.”