METHOD FOR ADDING ALLOY ELEMENT OF WHICH VAPOR PRESSURE IS INCREASED BY TEMPERATURE OF MOLTEN STEEL TO MOLTEN STEEL

摘要

PURPOSE:To melt efficiently and uniformly a titled alloy element in a molten steel by adding a wire contg. said element to the molten steel through a lance which is immersed in the molten steel in a manner as to prevent the intrusion of the molten steel to the inside thereof by an increased-pressure gas and is coated externally with refractories. CONSTITUTION:The molten steel 1 is filled in a ladle 10 and the lance 2 which is externally coated with the refractories 20 is immersed therein. The top end of the lance 2 is communicated via a wire guide 30 to a wire feeder box 31. The increased-pressure gas such as Ar is fed from the inside of the box 31 into the lance 2 and the gaseous pressure is maintained to the extent at which the gas is not discharged from the bottom end of the lance 2 to maintain the bath surface of the molten metal intruding into the lance 2 at the bottom end of the lance. An inert gas is at the same time blown into the molten steel through a blowing plug 11 in the bottom of the ladle 10 to stir the molten metal and the wire 3 contg. the alloy element such as Ca is delivered from a wire feeder 34 in the box 31 through a guide 30 and the lance 2 into the molten steel.