Molten seal for use in continuous casting of metal ingots

Abstract

A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

1 . A casting furnace for manufacturing a metal cast having an outer periphery, the furnace comprising: 
 an interior chamber having a sidewall;    a passage wall having an inner periphery which defines a passage extending through the sidewall of the interior chamber for communicating with the interior chamber and with atmosphere external to the interior chamber;    a metal cast pathway which extends from the interior chamber through the passage, which has an outer periphery and which is adapted for moving the metal cast from the interior chamber to the external atmosphere with the outer periphery of the metal cast coincident with the outer periphery of the pathway; and    a molten bath of coating material which provides during manufacture of the metal cast a liquid seal within the passage capable of preventing the external atmosphere from entering the interior chamber without the use of an additional seal which circumscribes the metal cast pathway and has a surface coincident with the outer periphery of the pathway below the liquid seal.    
   
   
       2 . The furnace of  claim 1  wherein the passage has a narrowest portion with a transverse cross-sectional shape adapted to be larger than a transverse cross-sectional shape of the metal cast.  
   
   
       3 . The furnace of  claim 2  further comprising a continuous casting mold in the interior chamber; an inner surface on the mold defining a transverse cross-sectional shape adapted to define the transverse cross-sectional shape of the metal cast; and wherein the narrowest portion of the passage has a transverse cross-sectional shape substantially the same as and larger than the transverse cross-sectional shape defined by the inner surface of the mold.  
   
   
       4 . The furnace of  claim 1  in combination with the metal cast; and wherein the metal cast has a transverse cross-sectional shape; and the passage has a narrowest portion with a transverse cross-sectional shape larger than that of the metal cast.  
   
   
       5 . The combination of  claim 4  wherein the molten bath is in contact with the outer periphery of the metal cast to form a protective barrier thereon as the metal cast moves from the interior chamber to the external atmosphere.  
   
   
       6 . The furnace of  claim 1  further comprising a section of the inner periphery of the passage wall which defines a narrowest portion of the passage and is spaced from and adjacent the outer periphery of the metal cast pathway and adapted to define a thickness of molten material from the molten bath which is applied to the outer periphery of the metal cast as it moves through the passage.  
   
   
       7 . The furnace of  claim 1  further comprising a source of particulate material; and a dispenser for moving the solid particulate material from the source to adjacent the metal cast pathway.  
   
   
       8 . The furnace of  claim 7  in combination with the metal cast; and further comprising a heat source for melting the solid material, the heat source comprising heat radiating from the metal cast.  
   
   
       9 . The combination of  claim 8  wherein the heat radiating from the metal cast is sufficient to melt the solid material.  
   
   
       10 . The furnace of  claim 7  further comprising an exit end on the dispenser adjacent the metal cast pathway and above the molten bath.  
   
   
       11 . The furnace of  claim 1  further comprising a source of particulate material; and a dispenser for moving the solid particulate material from the source to adjacent the molten bath.  
   
   
       12 . The furnace of  claim 11  in combination with the metal cast; and further comprising a heat source for melting the particulate material, the heat source comprising heat radiating from the metal cast.  
   
   
       13 . The combination of  claim 12  wherein the heat radiating from the metal cast is sufficient to melt the solid material.  
   
   
       14 . A casting furnace for manufacturing a metal cast, the furnace comprising: 
 an interior chamber having a sidewall with a top and a bottom;    a passage wall having an inner periphery which defines a passage extending through the sidewall from the top to the bottom for communicating with the interior chamber and with atmosphere external to the interior chamber;    a metal cast pathway extending from the interior chamber through the passage and adapted for moving the metal cast from the interior chamber to the external atmosphere;    a section of the inner periphery of the passage wall which defines a narrowest portion of the passage and which is spaced outwardly from and adjacent the metal cast pathway;    a lowermost point on the section of the inner periphery;    an annular cavity in the passage defined between the metal cast pathway and passage wall; and    a molten bath of coating material in the annular cavity extending within the narrowest portion of the passage downwardly to the lowermost point and providing during manufacture of the metal cast a liquid seal which prevents the external atmosphere from entering the interior chamber through the passage.    
   
   
       15 . The furnace of  claim 14  further comprising a continuous casting mold in the interior chamber; an inner surface on the mold defining a transverse cross-sectional shape adapted to define a transverse cross-sectional shape of the metal cast; and wherein the narrowest portion of the passage has a transverse cross-sectional shape substantially the same as and larger than the transverse cross-sectional shape defined by the inner surface of the mold.  
   
   
       16 . The furnace of  claim 14  in combination with the metal cast; and wherein the metal cast has a transverse cross-sectional shape; and the passage has a narrowest portion with a transverse cross-sectional shape larger than that of the metal cast.  
   
   
       17 . The combination of  claim 16  wherein the metal cast has an outer periphery; and the molten bath is in contact with the outer periphery of the metal cast to form a protective barrier thereon as the metal cast moves from the interior chamber to the external atmosphere.  
   
   
       18 . The furnace of  claim 14  further comprising a source of particulate material; and a dispenser for moving the solid particulate material from the source to adjacent the molten bath.  
   
   
       19 . The furnace of  claim 18  in combination with the metal cast; and further comprising a heat source for melting the particulate material, the heat source comprising heat radiating from the metal cast.  
   
   
       20 . The combination of  claim 19  wherein the heat radiating from the metal cast is sufficient to melt the solid material.