Mechanism of Reaction between Refractory Aluminum Deoxidised Molten Steel

The interaction between MgO-lined ladles and aluminum deoxidised molten steel during ladle refining was analyzed to understand the formation mechanisms of inclusions in steel. This research involved experimental studies alongside a thermodynamic analysis to clarify the reactions occurring between the refractory materials and the molten steel. Results indicated that internal oxidation-reduction processes take place within the MgO-C refractory, leading to the development of a thin oxide layer at the interface. This layer is formed by the reaction between magnesium vapor and aluminum dissolved in the molten steel, coupled with CO gas from the MgO-C interaction. The oxide inclusions resulting from this process primarily consist of MgO and Al2O3, with fine inclusions believed to originate as secondary inclusions during the cooling and solidification phases. The findings further revealed that as vacuum refining progresses and pressure diminishes, the chemical compatibility of carbon-bonded magnesia for ladle lining decreases, affecting product quality. This study contributes crucial insights into optimizing steelmaking processes to enhance the quality of finished products.