| 摘要 |
PURPOSE:To improve the yield of addition of additives by adding the additives by using a cylindrical body immersed diagonally into molten steel in adding the additives to the molten steel in a tundish. CONSTITUTION:In adding additives 11 having high activity of rare earth element such as Ca or Ce to the molten steel 1 in a tundish 2, a specific cylindrical body 3 made of refractories, and a piping 7 for high pressure and a piping 8 for reduced pressure are connected thereto. The leading end of the body 3 is immersed into the molten steel diagonally down to near the bottom of the tundish, thence the internal pressure of the body 3 is increased or decreased by regulating the flow control valves 5, 9 of the piping 7 and the piping 8. At the time when the molten steel 1 is reciprocated in the body 3 by the change in the internal pressure, a feeder 13 is operated to add the additives 11 to the molten steel 1 in the body 3, whereby they are supplied to the deep part of the molten steel 1 in the tundish. An inert gas atmosphere is maintained in the body 3, and since no molten slag 4 exists, the additives are added to the molten steel in high yields without being oxidized and consumed by air and molten slag. |
