Casting Process and Apparatus

Abstract

A casting method includes coupling a mold to a crucible, the mold having one or more part-defining cavities and one or more feed passageways. A first rotating of the crucible and mold pours molten metal from the crucible through the one or more feed passageways into the one or more part-defining cavities. A second rotating of the crucible and mold returns molten metal from the one or more feed passageways, while leaving the part-defining cavities filled.

1 . A casting method comprising:
 coupling a mold to a crucible, the mold having:
 one or more feed passageways, each of the feed passageways in fluid communication with a constriction, the constriction forming a gate portion of the feed passageway located between an upstream portion and a downstream portion; 
 one or more part defining cavities, each of the part defining cavities in fluid communication with one of the feed passageways via one of the constrictions; 
 localized insulation arranged along the upstream portion of the one or more feed passageways; and 
 an enhanced local surface exposure arranged along the downstream portion of the one or more feed passageways; 
   first rotating the crucible and mold to pour molten metal from the crucible through the one or more feed passageways into the one or more part-defining cavities; and   second rotating the crucible and mold to return molten metal from the one or more feed passageways, while leaving the part-defining cavities filled.   
     
     
         2 . The method of  claim 1  wherein the one or more feed passageways comprise:
 a pour cone; and 
 at least one downsprue between the pour cone and the part-defining cavities. 
 
     
     
         3 . The method of  claim 2  wherein:
 the second rotating returns said molten metal from the pour cone. 
 
     
     
         4 . The method of  claim 3  wherein:
 the second rotating returns said molten metal from the downsprue and the upstream portion of the feed passageways. 
 
     
     
         5 . The method of  claim 2  wherein:
 prior to the second rotating, metal at a lower part of the downsprue solidifies so that only a portion of metal from an upper part of the downsprue is returned. 
 
     
     
         6 . The method of  claim 2  wherein:
 there is a single downsprue to which a plurality of said part-defining cavities are coupled by gates. 
 
     
     
         7 . The method of  claim 6  wherein:
 the plurality of said part-defining cavities are arranged in a plurality of vertically-arrayed groups. 
 
     
     
         8 . The method of  claim 1  wherein:
 the process is repeated with the same crucible and a series of molds; and 
 at least a portion of the returned metal from one mold is poured into the next said mold. 
 
     
     
         9 . The method of  claim 8  further comprising:
 charging the crucible with additional metal prior to the pouring into the next said mold. 
 
     
     
         10 . The method of  claim 9  wherein charging the crucible comprises introducing 10-50% of the metal mass poured. 
     
     
         11 . The method of  claim 1  wherein:
 the return is of 10-50% of metal mass poured. 
 
     
     
         12 . The method of  claim 1  wherein:
 the return is after metal in the part-defining cavities has solidified. 
 
     
     
         13 . The method of  claim 1  wherein:
 the metal is a nickel-based superalloy or a cobalt-based superalloy. 
 
     
     
         14 . The method of  claim 1  wherein:
 the part-defining cavities cast gas turbine engine components. 
 
     
     
         15 - 19 . (canceled) 
     
     
         20 . The method of  claim 1  wherein the localized insulation is a fibrous ceramic material.