| 摘要 |
PURPOSE:To stably perform the refining of molten steel, in an apparatus for refining molten steel in a jet stream type ladle, by providing a buffer tank for buffering the pressure of the gas used in pressurizing the molten steel in the ladle and timewise controlling the pressure of the gas in said tank by a control means. CONSTITUTION:A refractory hollow pipe 3 is immersed in a ladle 1 in which molten steel was received and branched to be connected not only to a pressurizing N2-gas source 6 through an opening and closing valve 4 and a buffer tank 11 but also to a vacuum pump 7 through an opening and closing valve 5. The valve 4 is closed while the valve 5 is opened to evacuate the hollow pipe 3 and, during this evacuation period, N2-gas is charged in the buffer tank 11 so that the pressure therein reaches the buffer tank charge pressure set value operated by an operation control means 9. Next, valves 12, 5 are closed while the valve 4 is opened and N2-gas is fed in the hollow pipe 3 to pressurized the same. By this method, the molten steel in the hollow pipe 3 is moved up and down to perform the secondary refining of the molten steel under stiring. By timewise controlling this operation by a control means and using the buffer tank 11 in buffering the pressure of the pressurizing gas, secondary refining is stably performed without flooding the molten steel 2 from the ladle under excessive pressure. |
