Apparatus for producing directionally solidified castings

In an apparatus for the production of directionally solidified castings including a ceramic mold having an open bottom is supported on a chill plate, and means for pouring molten metal into the mold, the chill plate defining a surface for direct contact with the molten metal whereby the metal initially solidifies adjacent the chill plate with the casting thereafter solidifying progressively away from the chill plate, the portion of the metal contacting the chill plate and initially solidifying tending to shrink and to draw away from said chill plate surface thereby inhibiting heat transfer between the solidified metal and the chill plate, the improvement comprising a heat conductive plug member having an undercut surface area incorporated in said chill plate for communication with said open bottom of said mold, said casting thereby solidifying to said surface area of the plug member whereby the casting is securely held in intimate contact with the plug member and is inhibited against drawing away from said chill plate surface upon shrinkage of the metal, heat transfer between the solidified metal and the chill plate being thereby enhanced and heat thereby being withdrawn through the plug member and the chill plate as the casting solidifies, coolant passages defined by said chill plate for the circulation of a coolant, means for delivering coolant to said passages, a bore defined by said chill plate, said plug member being received in said bore, said bore extending from said chill plate surface to said coolant passages, and said plug member extending into said passages for direct contact of the plug member with the coolant.