Method and Apparatus for Casting

Abstract

A method of casting an alloy is provided, comprising the steps of pouring molten alloy into a mould ( 18 ), moving the mould ( 18 ) to a first position inside a chamber ( 12 ), the chamber ( 12 ) including a volume of quenchant ( 16 ), increasing the pressure within the chamber ( 12 ), and moving the mould ( 18 ) to a second position in which at least a portion of the mould ( 18 ) is submersed in the quenchant ( 16 ), so as to reduce the temperature of the mould ( 18 ).

1 . A method of casting an alloy, comprising the steps of:
 pouring molten alloy into a mould;   moving the mould to a first position inside a chamber, the chamber including a volume of quenchant;   increasing a pressure within the chamber to above atmospheric pressure; and   moving the mould to a second position in which at least a portion of the mould is submersed in the quenchant, so as to reduce the temperature of the mould.   
     
     
         2 . A method of casting an alloy, comprising the steps of:
 moving a mould to a position within a chamber, the chamber including a volume of quenchant;   reducing a pressure within the chamber to below atmospheric pressure; and   causing molten alloy to enter the chamber, and to enter the mould under the reduced pressure within the chamber.   
     
     
         3 . A method according to  claim 2 , further comprising the steps of:
 increasing the pressure within the chamber to above atmospheric pressure; and   moving the mould to a second position in which at least a portion of the mould is submersed in the quenchant, so as to reduce the temperature of the mould.   
     
     
         4 . A method according to  claim 3 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed before the step of moving the mould to a second position. 
     
     
         5 . A method according to  claim 3 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed after the step of moving the mould to a second position. 
     
     
         6 . A method according to  claim 3 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed as the mould is moved to the second position. 
     
     
         7 . A method according to  claim 3 , further comprising the step of:
 before causing molten alloy to enter the chamber, sealing an inlet to the chamber with a sacrificial seal, and   wherein the step of causing molten alloy to enter the chamber comprises causing the molten alloy to melt the sacrificial seal.   
     
     
         8 . A method according to  claim 7 , wherein the sacrificial seal is formed substantially from the alloy being cast. 
     
     
         9 . A method according to  claim 3 , wherein the step of moving the mould to a second position comprises moving the mould at a constant rate. 
     
     
         10 . A method according to  claim 3 , further comprising the step of moving the mould back towards the first position once the mould is quenched. 
     
     
         11 . A method according to  claim 3 , further comprising the step of venting gas from inside the chamber at a time period after the mould is moved to the second position. 
     
     
         12 . A casting apparatus, comprising:
 a pressurisable chamber having a part for receiving a quenchant;   a pressurising means for altering a pressure within the chamber;   a sealable opening to provide access to an interior of the chamber; and   a support part for supporting a mould, the support part being moveable between a first, non-quenching, position and a second, quenching, position wherein the second position is closer than the first position to a lowermost portion of the part for receiving a quenchant.   
     
     
         13 . A casting apparatus, comprising:
 a pressurisable chamber having a part for receiving a quenchant;   a sealable opening to provide access to an interior of the chamber; and   a container for receiving molten alloy, the container being connected to an interior of the chamber by a passageway, and being closable by a meltable sacrificial seal to separate the container from the interior of the chamber.   
     
     
         14 - 31 . (canceled) 
     
     
         32 . A method according to  claim 1 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed before the step of moving the mould to a second position. 
     
     
         33 . A method according to  claim 1 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed after the step of moving the mould to a second position. 
     
     
         34 . A method according to  claim 1 , wherein the step of increasing the pressure within the chamber to above atmospheric pressure is performed as the mould is moved to the second position. 
     
     
         35 . A method according to  claim 1 , further comprising the step of:
 before causing molten alloy to enter the chamber, sealing an inlet to the chamber with a sacrificial seal, and   wherein the step of causing molten alloy to enter the chamber comprises causing the molten alloy to melt the sacrificial seal.   
     
     
         36 . A method according to  claim 35 , wherein the sacrificial seal is formed substantially from the alloy being cast. 
     
     
         37 . A method according to  claim 1 , wherein the step of moving the mould to a second position comprises moving the mould at a constant rate. 
     
     
         38 . A method according to  claim 1 , further comprising the step of moving the mould back towards the first position once the mould is quenched. 
     
     
         39 . A method according to  claim 1 , further comprising the step of venting gas from inside the chamber at a time period after the mould is moved to the second position.