Twin-roll strip caster and casting method using same

Abstract

A twin-roll strip caster includes: a pair of casting rolls rotating in opposite directions to each other, and having an edge dam adhering to both end surfaces of the casting rolls in a length direction of the casting rolls; a submerged nozzle discharging molten steel between the pair of casting rolls; a meniscus shield disposed above the molten steel supplied through the submerged nozzle to prevent the molten steel from contacting air; and a focused gas supply nozzle disposed between the submerged nozzle and the meniscus shield to supply inert gas therebetween so as to displace air between the submerged nozzle and the meniscus shield before the molten steel is supplied.

What is claimed is: 
     
         1 . A twin-roll strip caster comprising:
 a pair of casting rolls rotating in opposite directions to each other, and having an edge dam adhering to both end surfaces of the casting rolls in a length direction of the casting rolls;   a submerged nozzle discharging molten steel between the pair of casting rolls;   a meniscus shield disposed above the molten steel supplied through the submerged nozzle to prevent the molten steel from contacting air; and   a focused gas supply nozzle disposed between the submerged nozzle and the meniscus shield to supply inert gas therebetween so as to displace air between the submerged nozzle and the meniscus shield before the molten steel is supplied.   
     
     
         2 . The twin-roll strip caster of  claim 1 , wherein the focused gas supply nozzle is disposed in the meniscus shield to dispense the inert gas to surfaces of the pair of casting rolls between the submerged nozzle and the edge dam. 
     
     
         3 . The twin-roll strip caster of  claim 1 , wherein the focused gas supply nozzle dispenses the inert gas from above one casting roll to a surface of the other casting roll. 
     
     
         4 . The twin-roll strip caster of  claim 3 , wherein the focused gas supply nozzle comprises:
 a first focused gas supply nozzle dispensing the inert gas from above the one casting roll, positioned at one end of the submerged nozzle in a width direction, to the surface of the other casting roll; and   a second focused gas supply nozzle dispensing the inert gas from above the other casting roll, positioned at the other end of the submerged nozzle in the width direction, to the surface of the one casting roll.   
     
     
         5 . The twin-roll strip caster of  claim 1 , further comprising an air discharging unit disposed on one side of the meniscus shield to discharge air. 
     
     
         6 . A casting method for a twin-roll strip caster comprising:
 an assembling operation of combining a pair of casting rolls, a preheated edge dam, a preheated submerged nozzle, and a meniscus shield with one another;   an inert gas supplying operation of displacing air remaining between the pair of casting rolls and the meniscus shield by supplying inert gas therebetween at high pressure before molten steel is supplied through the preheated submerged nozzle after the assembling operation; and   a casting operation of supplying the molten steel through the submerged nozzle after air is displaced by the inert gas supplying operation.   
     
     
         7 . The casting method of  claim 6 , wherein the inert gas supplying operation comprises supplying the inert gas between the preheated edge dam and the preheated submerged nozzle. 
     
     
         8 . The casting method of  claim 6 , wherein the inert gas supplying operation further comprises an air discharging operation of discharging air remaining between the pair of casting rolls and the meniscus shield while the inert gas is supplied. 
     
     
         9 . The casting method of  claim 6 , wherein the inert gas supplied in the inert gas supplying operation is supplied at a flow rate of 500 liter/min to 2,500 liter/min.