| 摘要 |
PURPOSE:To prevent the molten metal having been degassed from being resucked and improve degassing effect by supplying a inert gas for sealing and an Al wire for deoxidizing into the molten metal discharge pipe of the vacuum degassing device attached to a continuous casting device. CONSTITUTION:A vacuum degassing tank 5 is mounted into the molten metal 3 in a tundish 2, and the terminal of a molten steel discharge pipe 7 is connected to a tundish nozzle 9. An Al wire 12 and an inert gas such as Ar are introduced to the midpart of this pipe 7 through an addition port 14. If dissolved oxygen O2 still exists in the molten metal despite the vacuum degassing treatment in the tank 5, it is deoxidized by the Al wire 12 and removed; at the same time, in order to prevent air from entering the molten steel simultaneously at the time of adding the Al wire 12, Ar or the like is simultaneously introduced through a steel pipe 15 for sealing, whereby the Al addition port 14 is sealed from air. Even if the molten steel 3 contains much of initial oxygen, if flows into the continuous casting mold in the state that it is highly deoxidized by the vacuum degassing and Al deoxidation. |
