| 摘要 |
PURPOSE:To prevent the clogging of the gas ejection port of a bubbling lance to be used in a ladle refining furnace owing to sticking of a base metal thereto by increasing the gas ejection rate from the lance in the stage of inserting said lance into or drawing out of a molten steel and changing the gas ejection rate when the ejection rate decreases at a specific rate. CONSTITUTION:The gas bubbling lance 6 by gaseous Ar to be used in the ladle refining furnace 1 is a lance for powerful stirring in the stage of adding an alloy iron, etc. to the molten steel 4 and blows gaseous Ar usually at about 1,500-2,000l/min. The lance 7 is used at 500-800l/min flow rate of the gaseous Ar in order to stir lightly the molten steel 4. The ejection flow rate of the gaseous Ar is increased respectively by about 200-300l/min and the decrease rate to decrease the gas flow rate to the original flow rate is made to <=200l/min in the stage of putting these lances into and out of the molten steel 4, by which the intrusion of the base metal 8 into the gaseous Ar ejection ports 6a, 7a and the consequent clogging thereof are prevented. |
