Influence of Al₂O₃ Content on the Performances of BN‐Based Side Dams for Twin‐Roll Strip Casting

Based on the study of BN‐based side dams with varying Al 2 O 3 contents for twin‐roll strip casting of silicon steel, it is demonstrated that increasing Al 2 O 3 content enhances corrosion resistance to silicon steel while maintaining comparable thermal, mechanical, and wear properties. The corrosion depth of the side dams exhibits a positive correlation with the silicon content in the molten steel; specifically, an increase in silicon content from Si‐free to 3.0 wt% results in an ≈80% increase in corrosion depth. Notably, side dams with higher Al 2 O 3 content demonstrate superior corrosion resistance in silicon steel, showing a 24% enhancement when the Al 2 O 3 content is increased from 5 to 10 in 1.5 wt% silicon steel. Increasing Al 2 O 3 content from 5 to 10 wt% elevates the wetting angle by 7.2%, reducing the spreading of molten steel on the surface of side dams, thereby enhancing corrosion resistance. Thermodynamic simulations indicate that increasing Al 2 O 3 content in side dams promotes protective slag formation, suppresses liquid phase generation, and enhances corrosion resistance during casting of silicon steel. This study provides a theoretical foundation for optimizing the composition of BN‐based side dams to improve their performance in twin‐roll strip casting of silicon steel.