| 摘要 |
PURPOSE:To improve the decarburizing and degasifying effect on molten steel by making the space between a ladle and a vacuum vessel airtight, and pressing the surface of the molten steel in the ladle when the molten steel in the ladle is degasified with a circulating-system vacuum degasification apparatus. CONSTITUTION:A vacuum vessel 1 and a ladle 6 are hermetically closed with a lid 3 when molten steel is decarburized, densitrified, and dehydrogenated with an RH-system vacuum degasification apparatus. An inert gas such as AR is blown in from a tuyere 9 on the bottom wall or at the lower part of the side wall of the vacuum vessel 1, and a gas of Al, etc. at high pressure is introduced from a gas introducing port 4 to press the surface of molten steel 7 in the ladle 6. Since the depth of molten steel 2 in the vacuum vessel 1 is increased as compared with the case of a conventional RH-system apparatus and the flow velocity of the molten steel circulating in the vicinity of the refractory at the bottom of the vacuum vessel 1 is reduced, the refreactory is not abnormally melted and damaged by the gas blown into the molten steel, and the decarburizing, denitrifying, and dehydrogenating effect on the molten steel 7 in the ladle 6 is improved. |
