| 摘要 |
PURPOSE:To reduce the period of time required for refining and produce the titled steel efficiently by a method wherein an inert gas and an O2 gas are blown into a molten high-Cr steel in a ladle respectively from the bottom and an upper part of the ladle so as to lower the C content of the molten steel to a predetermined value or below, and further an inert gas of specified composition is blown into the molten steel. CONSTITUTION:The ladle containing a molten high-Cr steel containing 0.8-2.5% of C and 10-35% of Cr is placed in an evacuated tank. While blowing an inert gas into the molten steel from the bottom of the ladle, the tank is evacuated and then an O2 gas is blown to the surface of the molten steel to lower the C content of the steel to 0.07% or below. In this case, the inert gas is blown in at a flow rate of not lower than 15Nl/sec per ton of the molten steel. Then, the thus decarburized molten steel is supplied with an inert gas which has the composition as expressed by the equation. As a result, a slage containing not less than 20% of SiO2 and not more than 25% of Cr2O3 is formed in a amount of not less than 1kg per ton of the molten steel, and the titled steel containing not more than 0.01% of C and not more than 0.01% of N is obtained. |
