Continuous casting apparatus for ingots obtained from titanium or titanium alloy

Abstract

A continuous casting apparatus continuously casts an ingot formed of titanium or a titanium alloy. The apparatus includes a bottomless mold with a circular cross-sectional shape and a plasma torch. In the bottomless mold, a molten metal is poured from a top opening and the molten metal is solidified and the molten metal solidified is pulled out downward. The plasma torch is disposed on an upper side of the molten metal in the mold and generates a plasma arc that heats the molten metal. A plurality of plasma torches are disposed on the upper side of the molten metal in the mold. The plurality of plasma torches are moved in a horizontal direction above a melt surface of the molten metal along a trajectory keeping a distance not to allow for interference with each other.

1 . A continuous casting apparatus of an ingot formed of titanium or a titanium alloy, which continuously casts the ingot formed of titanium or a titanium alloy, the continuous casting apparatus comprising: a bottomless mold with a circular cross-sectional shape in which a molten metal prepared by melting titanium or a titanium alloy is poured from a top opening and the molten metal is solidified and the molten metal solidified is pulled out downward; and a plasma torch which is disposed on an upper side of the molten metal in the mold and generates a plasma arc that heats the molten metal, wherein
 a plurality of plasma torches are disposed on the upper side of the molten metal in the mold, and   the plurality of plasma torches are moved in a horizontal direction above a melt surface of the molten metal along a trajectory keeping a distance not to allow for interference with each other.   
     
     
         2 . The continuous casting apparatus of an ingot formed of titanium or a titanium alloy as claimed in  claim 1 , wherein
 the number of the plasma torches is  2 , and   the plasma torches are moved such that when one plasma torch is located on an upper side in the vicinity of an edge of the mold, the other plasma torch is located near a central part of the mold.   
     
     
         3 . The continuous casting apparatus of an ingot formed of titanium or a titanium alloy as claimed in  claim 2 , wherein
 assuming that a radius of the melt surface is R, the plasma torch is moved to locate its center on a trajectory formed after an inner circumferential arc having a radius of 0<r1<R/2 from a center of the melt surface and an outer circumferential arc having a radius of R/2<r2<R from the center of the melt surface are connected by a straight line, and   a plasma output of the plasma torch during movement in the inner circumferential arc is controlled to be lower than a plasma output of the plasma torch during movement in the outer circumferential arc.   
     
     
         4 . The continuous casting apparatus of an ingot formed of titanium or a titanium alloy as claimed in  claim 3 , wherein each of the plasma torches is moved within either one range of two divided semicircles as viewed from a front of the melt surface. 
     
     
         5 . The continuous casting apparatus of an ingot formed of titanium or a titanium alloy as claimed in  claim 3 , wherein the movement is controlled to afford a distance of R/2 or more between centers of the plasma torches. 
     
     
         6 . The continuous casting apparatus of an ingot formed of titanium or a titanium alloy as claimed in  claim 4 , wherein the movement is controlled to afford a distance of R/2 or more between centers of the plasma torches.