| 摘要 |
PURPOSE:To supply gaseous N2 stably with good hit rates by controlling the discharge rate of the gaseous N2 from an immersion lance and the immersion depth of the lance from the liquid level in a way as to satisfy the relations of the specific equations. CONSTITUTION:A lance is immersed under the liquid level of molten steel from above the liquid level in a vessel, and gaseous N2 is blown into the molten steel through this immersed lance. A prescribed amt. of the N2 is added to the molten steel by such blowing of the gaseous N2, whereby the nitrogen-contg. molten steel is produced. At this time, the discharge velocity V' of the gaseous N2 from the immersed lance and the immersion depth L of the lance from the liquid level are so controlled as to satisfy the relation of the equationI. In the equation, L is a metric unit, V is not the V' itself but is the ratio of the velocity of sound expressed by the equation II. The total area of the discharge hole of the lance in the equation II is the sum total of the areas of plural discharge holes if the lance has the plural discharge holes. |
