Capturing the Interaction Between Mold Flux and Different Steel Compositions During Industrial-Scale Continuous Casting Trials

Mold fluxes play pivotal roles during the continuous casting process, and it is important to choose a correct flux for the steel grade being cast. In the present work, interactions between various steel grades and CaO-SiO₂-based flux is captured through plant measurements. Mold slag pool depth and composition were measured at different durations during the casting process. Further, a kinetic model has been developed to validate the change in mold flux composition with time. The model is based on the effective equilibrium reaction zone concept, and is dynamically linked to the ChemApp thermodynamic library, which provides access to thermodynamic databases of the FactSage software. Casting parameters such as casting speed variation (1–1.35 m/s), slag pool depth (10–30 mm), and temperature (1500°C, 1400°C, and 1300°C) across each flux layer have been used as inputs to the model. Three plant cases were validated using the model, namely low-C steel (C ~ 0.05%, Mn ~ 0.5%, Al ~ 0.05%), medium-C steel (C ~ 0.15%, Mn ~ 1.1%, Al ~ 0.05%), and high-Si steel (C ~ 0.005%, Mn ~ 0.2%, Al ~ 1%, Si ~ 3.2%). The model predicted the change in slag composition in real time, which showed a significant SiO₂ reduction from the mold slag and at the same time an Al₂O₃ pick-up into it.