Alumina　Buildup　Behavior　in　the　Tundish　Nozzle　during　Reoxidation　of　Molten　Steel

Abstract

The　buildup　behavior　of　Al203 in　the　continuous　caster　tundish　nozzle　during　the　time　when reoxidation　of　molten　steel　is　in　progress　in　the　tundish　was　studied. The　study　revealed　that molten　FeO　formed　in　the　tundish　during　reoxidation　of　molten　steel，with　some　part　of　the　molten FeO　still　remaining　unreduced， flows　through　the　tundish　nozzle　into　the　mold. It　also　revealed　that Al203 particles，ranging　from　a　few　to　approximately 10 μm　in　size， built　up　in　the　tundish　nozzle while　forming　FeAl204 between　these　particles． From　the　results　of　this　study　and　an　analysis made　by　using　a　newly　proposed　model　for　Al203 buildup，it　is　considered　that　Al203 particles　in the　molten　steel　adhere　to　the　nozzle　face， with　molten　FeO　serving　as　a　binder， and　are　not removed　by　the　stream　of　molten　steel　running　through　the　nozzle.