Directional solidification apparatus and related methods

Abstract

A directional solidification apparatus includes a mold heating chamber, a solidification chamber, and a gas source. The solidification chamber is adjacent the mold heating chamber for solidifying molten metal formed from an air melt allow system as a cast body as the metal is withdrawn from the mold heating chamber. The gas source is in fluid communication with the mold heating chamber for providing a pressurized atmosphere for directionally solidifying metal as a cast body having single crystal or multi-crystal columnar micro structure.

What is claimed is: 
     
         1 . A directional solidification apparatus, comprising:
 a mold heating chamber;   a solidification chamber adjacent the mold heating chamber for solidifying molten metal comprising an air melt alloy system as the metal is withdrawn from the mold heating chamber; and   a gas source in fluid communication with the mold heating chamber, wherein the gas source is configured to provide a pressurized atmosphere for directionally solidifying the metal as a cast body with single crystal or multi-crystal columnar microstructure.   
     
     
         2 . An apparatus as recited in  claim 1 , wherein apparatus is configured for solidifying a cast body formed from carbon steel, low alloy steel, or a non-nickel based alloy system. 
     
     
         3 . An apparatus as recited in  claim 1 , wherein the gas source an inert gas source. 
     
     
         4 . An apparatus as recited in  claim 1 , wherein the inert gas source is an argon gas source. 
     
     
         5 . An apparatus as recited in  claim 1 , wherein the gas source is an oxidizing gas source. 
     
     
         6 . An apparatus as recited in  claim 1 , further including a valve fluidly coupling the gas source with the solidification chamber for providing an inert solidification atmosphere during solidification of the cast body. 
     
     
         7 . An apparatus as recited in  claim 1 , further including a heating element arranged within an interior chamber of the mold heating chamber. 
     
     
         8 . An apparatus as recited in  claim 1 , further including a baffle separating the mold heating chamber from the solidification chamber constructed from a material suitable for use in a high-temperature environment with an oxidizing atmosphere. 
     
     
         9 . An apparatus as recited in  claim 1 , wherein the solidification chamber includes a liquid metal bath for removing heat from the metal. 
     
     
         10 . An apparatus as recited in  claim 8 , wherein the baffle is constructed from a material selected from the group consisting of alumina, partially stabilized zirconia, alumina-silicate, cordierite, and an oxide-based ceramic. 
     
     
         11 . An apparatus as recited in  claim 1 , further including an air impingement module in fluid communication with the solidification chamber for removing heat from the cast body using air. 
     
     
         12 . An apparatus as recited in  claim 1 , further including a water ring disposed within the solidification chamber for removing heat from the cast body using a liquid coolant. 
     
     
         13 . An apparatus as recited in  claim 1 , wherein the gas source is configured for evacuating an interior of the apparatus and charging the atmosphere with an inert gas for solidifying the cast body. 
     
     
         14 . An apparatus as recited in  claim 1 , wherein an interior of the apparatus is a hyperbaric controlled environment for reducing migration of volatile alloy constituents from molten metal to the apparatus interior during solidification of the cast body. 
     
     
         15 . An apparatus as recited in  claim 1 , wherein an interior of the apparatus is a hypobaric controlled environment for reducing migration of volatile alloy constituents from molten metal to the apparatus interior during solidification of the cast body. 
     
     
         16 . A directional solidification apparatus, comprising:
 a mold heating chamber;   a solidification chamber adjacent the mold heating chamber for solidifying molten metal comprising an air melt alloy system as the metal is withdrawn from the mold heating chamber;   a baffle separating the mold heating chamber from the solidification chamber; and   a gas source in fluid communication with an interior of the mold heating chamber through a cooled valve, wherein the gas source is configured for charging apparatus interior with an inert atmosphere for directionally solidifying the metal as a cast body having single crystal or a multi-crystal columnar microstructure.   
     
     
         17 . A method of casting steel, comprising:
 introducing molten metal comprising an air melt alloy system into a mold heating chamber in a controlled atmosphere;   withdrawing the molten metal into a solidification chamber in the controlled atmosphere; and   removing heat from the molten metal in a controlled atmosphere and developing a directionally solidified cast body with single crystal or a multi-crystal columnar microstructure.   
     
     
         18 . A method as recited in  claim 17 , wherein the controlled atmosphere is an inert atmosphere. 
     
     
         19 . A method as recited in  claim 17 , wherein the controlled atmosphere is a positive pressure oxidizing atmosphere. 
     
     
         20 . A method as recited in  claim 17 , wherein the controlled atmosphere is a low vacuum oxidizing atmosphere.