Method of casting a metal article

Abstract

During the casting of the metal article, a mold is lowered from a furnace assembly into a body of an inert gas. A stream having a thermal conductivity greater than the thermal conductivity of the inert gas is directed against a first portion of the mold to initiate solidification of molten metal in the first portion of the mold. The stream is subsequently directed against portions of the mold disposed in the body of inert gas and disposed above the first portion of the mold to initiate solidification of molten metal and portions of the mold above the first portion of the mold. The stream may be formed of a molten metal. Alternatively, the stream may be formed of an inert gas in which particulate is entrained.

1 . A method of casting a metal article, said method comprising the steps of filling a mold with molten metal while the mold is disposed in a furnace, lowering the mold from the furnace in a body of inert gas, directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against a first portion of the mold disposed in the body of inert gas to initiate solidification of molten metal in the first portion of the mold, and directing the stream having a thermal conductivity greater than the thermal conductivity of the inert gas against portions of the mold disposed in the body of gas and disposed above the first portion of the mold to initiate solidification of molten metal in portions of the mold above the first portion of the mold. 
   
   
       2 . A mold as set forth in  claim 1  wherein said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against a first portion of the mold includes directing a stream of molten metal against the first portion of the mold. 
   
   
       3 . A method as set forth in  claim 1  wherein said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against a first portion of the mold includes directing a stream of the inert gas in which a particulate is entrained against the first portion of the mold. 
   
   
       4 . A method as set forth in  claim 1  further including the steps of collecting material from the stream and returning the collected material to the stream. 
   
   
       5 . A method as set forth in  claim 1  wherein said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against the first portion of the mold includes directing a stream of liquid against the first portion of the mold and allowing at least a portion of the liquid from the stream of liquid to move downwardly in the body of inert gas under the influence of gravity. 
   
   
       6 . A method as set forth in  claim 1  wherein said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against portions of the mold disposed above the first portion of the mold includes directing a stream of liquid against the portions of the mold disposed above the first portion of the mold and allowing liquid from the stream of liquid to move downwardly along portions of the mold disposed below a portion of the mold against which the stream of liquid is directed and to move downwardly in the body of inert gas under the influence of gravity. 
   
   
       7 . A method as set forth in  claim 1  wherein said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against the first portion of the mold includes directing a stream of liquid against the first portion of the mold at a first location in the body of inert gas, said step of directing a stream having a thermal conductivity greater than the thermal conductivity of the inert gas against portions of the mold disposed in the body of gas and disposed above the first portion of the mold includes directing a stream of liquid against the portions of the mold above the first portion of the mold at the first location in the body of inert gas. 
   
   
       8 . A method as set forth in  claim 7  wherein said step of directing a stream of liquid against the portions of the mold above the first portion of the mold is performed with the first portion of the mold at least partially exposed to the inert gas in the body of inert gas. 
   
   
       9 . A method as set forth in  claim 7  further including the step of collecting a body of the liquid which contains liquid which was directed against the mold in a stream of liquid, said step of collecting the body of liquid includes collecting the body of liquid at a location disposed at a level below the mold and with an upper surface of the body of liquid exposed to gas in the body of inert gas. 
   
   
       10 . A method as set forth in  claim 9  further including the step of pumping liquid from the body of liquid and at least partially forming the stream having a thermal conductivity greater than the thermal conductivity of the inert gas and which is directed against portions of the mold disposed above the first portion of the mold.