China's Refractories

Abstract: To clarify the effect of the tundish lining on the steel cleanliness, the MgO based and Al2O3 based gunning materials (GM) were used as the lining of the alumina crucibles, respectively, in which about 200 g of ultra-low carbon steel was charged at 1 823 K for 2 h in pure argon atmosphere. The chemical analysis was carried out to investigate the change of chemical composition of steel in contact with GM after high temperatures holding experiments. The steel cleanliness in terms of inclusion number density, inclusion size and inclusion  size distribution was evaluated by SEM and EDS. It was found that the MgO GM provided more oxygen and showed a stronger oxidizing capacity due to its higher content of reducible oxides (10.5 mass% SiO2+2 mass% Fe2O3). The use of Al2O3 GM resulted in an improved steel cleanliness and consequently Al2O3 GM could be a promising refractory material in the tundish lining.

Key words: tundish lining, steel, cleanliness, penetration