| 摘要 |
PURPOSE:To cast stably a billet having good surface characteristic and high grade by casting continuously the molten steel in a water cooled casting mold which is subjected to a surface treatment airtightly in a sealed chamber filled therein with an inert gas while stirring electromagnetically. CONSTITUTION:A sealed chamber 10 consisting of a bellows 5 filled therein with an insert gas is provided between a tundish 1 and a casting mold 3 to prevent oxidation of the molten steel in a tundish 1 in a continuous casting device which feeds the molten steel 2 through an immersion nozzle 7 into a water cooled casting mold 3 applied with a surface treatment of boron nitride or the like. The pressure PG in the bellows 5 corresponding to the height H of the surface of the molten steel 2 in the tundish 1 is regulated by controlling a gas feed valve 8 and release valve 9, whereby the meniscus level detected with a sensor 11 is maintained constant and the continuous casting is made stable. On the other hand, the molten steel 2 in the mold 3 is stirred by an electromagnetic induction coil 4 to make the cooling uniform, and the mold 2 having a low coefft. of friction is used, whereby a billet 12 having the good surface characteristics are obtd. |
