Cellular automaton modeling of the local corrosion of ZrO2-C refractories at slag/metal interfaces

Abstract

Understanding local corrosion mechanisms of ZrO₂-C (ZG) refractories is essential for extending submerged entry nozzle (SEN) lifespan and improving continuous casting efficiency. This study and analytically investigated local corrosion of ZG refractories at the slag/metal interface, where molten steel contacts mold fluxes. Refractory wettability significantly affects ZrO₂ content and corrosion rate. To elucidate these interactions, we developed a model focused on the slag/metal interface, incorporating a two-dimensional cellular automaton (CA) method. Using actual ZG microstructures, the CA simulation visualized corrosion behavior, revealing new insights. Despite considering only wettability changes, the model successfully replicated (1) observed correlations between ZrO₂ content and corrosion rate, and (2) time-dependent changes in corrosion depth and ZrO₂ area fraction. These results were achieved for critical ZrO₂ area fractions $f_{\text{Zc}}=0.01$, $0.15$, and $0.50$ in ZG refractories containing 79 and 86 wt.% ZrO₂. Findings support optimization of refractory design and process parameters.