| 摘要 |
PURPOSE:To execute heating and refining of a molten steel in parallel without spoiling the cleanliness of the molten steel by providing an electromagnetic coil enclosing the outside periphery of the zone of a reflux pipe where the protective shell is removed and subjecting the molten steel flowing in the reflux pipe to induction heating. CONSTITUTION:The plural reflux pipes 4 extending downward in the bottom of a vacuum vessel 1 are immersed into the molten steel 3 bath housed in a ladle 2 and while the molten steel 3 is circulated between the vessel 1 and the ladle 2, the refining is progressed. The protective shell of each reflux pipe 4 is partially removed over the entire periphery to expose refractories 9 and the electromagnetic induction coil 6 is disposed to enclose the outside periphery of such zone 10 at the time of executing such treatment. Electric current is caused to flow to the coil 6 so that the molten steel 3 flowing in the reflux pipe 4 is subjected to efficient induction heating. The temp. drop of the molten steel during the vacuum treatment is considerably decreased by such method and therefore, substantial time for the vacuum degassing treatment is assured.
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