Thermodynamic calculation on tundish slag with high basicity

Tundish slag is a key material affecting the metallurgical effect of tundish, and tundish slag with high basicity has become the main type of tundish slab for high-purity steel continuous casting process nowadays. In the present work, thermodynamic calculation on tundish slab with high basicity was conducted, and the results showed that the original MgO content of the tundish slab should be ≥6wt% for ensuring the dissolved MgO in liquid slag was saturated to effectively decrease the erosion of the tundish lining by the liquid slag. The viscosity of the liquid slag was less affected by w(CaO)/w(Al₂O₃) or w(MgO) of the tundish slag and mainly affected by temperature. With the temperature increased, the viscosity of the liquid slag decreases significantly. w(CaO)/w(Al₂O₃) and temperature play important roles on influencing the dissolution and adsorption capacity of the tundish slag for inclusions, and this capacity significantly increases with w(CaO)/w(Al₂O₃) and temperature increased. Based on the calculated results, w(CaO)/w(Al₂O₃) of tundish slag was increased from 1.3 to 2.4, and the T.[O] of the steel samples from tundish deceased by 28.0%.