Abstract
The effects of fluxes on MgO coating materials for tundish were investigated. As the number of charge in continuous casting was increased, the basicity of tundish slag was decreased due to the increase of silica formed by dissolution from rice hull. As a result, the wear of magnesia lining was increased. In aggregates of MgO coating materials, magnesioferrite was formed by the reaction between magnesia and ferric oxide formed by the oxidation of molten steel, while matrix parts of MgO coating materials were worn by CaO-Al2O3-SiO2 compounds. Silica in rice hull extracted to the molten slag reduced basicity of slag and formed forsterite in the result of its reaction with magnesia lining. Also, fayalite was formed from the reaction between silica and ferric oxide and it caused the increment of magnesia lining's wear. The wear of magnesia lining by flux of CaO-SiO2 was larger than that of Cao-Al2O3 and calcia in the flux increased the wear of magnesia lining through the formation of rankinite.