Interaction between Steel and Distinct Gunning Materials in the Tundish

抄録

Gunning materials are used as a dispensable protective layer to extend the tundish life. Their use however, affects the steel cleanliness by introducing steel reoxidation and exogenous inclusions. In the present work, the interaction between molten steel and three types of refractory, i.e. MgO, Al₂O₃, and MgO + 2MgO∙SiO₂ based gunning materials (GM) have been investigated. Compared to MgO and MgO + 2MgO∙SiO₂ GM, the Al₂O₃ GM exhibited better infiltration resistance to molten steel. The two phase MgO + 2MgO∙SiO₂ GM was found to be less prone to steel infiltration than single-phase MgO GM. The compositional evolution of steel influenced by gunning material was experimentally measured and also predicted with thermodynamic equilibrium calculations. The steel cleanliness in terms of inclusion size, number density, area fraction and morphology was measured and evaluated. Although large Al₂O₃/AlTiO_X inclusions were formed through the erosion of Al₂O₃ GM, the use of Al₂O₃ GM resulted in an improved steel cleanliness due to its lower content of reducible compounds compared to that of MgO and MgO + 2MgO∙SiO₂ GM.