Abstract: The fluidized bed is formed of particulate material suspended in a flow of gas. A flow of particulate suspended in gas is conducted between a lower end portion of the fluidized bed and an upper end portion of the fluidized bed to cool the upper end portion of the fluidized bed. The flow of particulate suspended in gas may be conducted from a lower end portion of the fluidized bed to an upper end portion of a fluidized bed. Alternatively, the flow of particulate suspended in gas may be conducted from the upper end portion of the fluidized bed to the lower end portion of the fluidized bed. If desired, the flow of particulate suspended in gas may be conducted to the upper end portion of the fluidized bed from a location spaced from the fluidized bed.

Abstract: As a mold containing molten metal is lowered from a heating chamber, a baffle extends around the mold. Force is transmitted from the mold to an inner section of the baffle to release connectors between the inner section of the baffle and an outer section of the baffle. As the connectors are released, a side surface on the inner section of the baffle moves out of the coplanar relationship with a side surface on the outer section of the baffle. The baffle may be integrally formed as one-piece. Rather than being formed as one-piece, the baffle may include separate pieces which form the inner and outer sections of the baffle. Alternatively, the inner section of the baffle may be disposed above and supported by the outer section of the baffle. Latches may be provided to interconnect the outer section of the baffle and the furnace assembly.

Abstract: A method of casting metal articles includes providing an array of article molds. The article molds are filled with molten metal. The molten metal is solidified in the article molds. During solidification of the molten metal, a plurality of solidification control elements function as heat sinks and radiation baffles. The solidification control elements are disposed between the article molds as the molten metal solidifies.

Abstract: The fluidized bed is formed of particulate material suspended in a flow of gas. A flow of particulate suspended in gas is conducted between a lower end portion of the fluidized bed and an upper end portion of the fluidized bed to cool the upper end portion of the fluidized bed. The flow of particulate suspended in gas may be conducted from a lower end portion of the fluidized bed to an upper end portion of a fluidized bed. Alternatively, the flow of particulate suspended in gas may be conducted from the upper end portion of the fluidized bed to the lower end portion of the fluidized bed. If desired, the flow of particulate suspended in gas may be conducted to the upper end portion of the fluidized bed from a location spaced from the fluidized bed.

Abstract: An apparatus for use in casting a metal article includes a furnace assembly into which a mold is raised and an annular fluidized bed adjacent to the furnace assembly. The mold is filled with molten metal and lowered into the fluidized bed. The molten metal is solidified in the mold as it is lowered into the fluidized bed. The mold and fluidized bed are then lowered. The fluidized bed is disposed in a container having annular inner and outer walls which are cooled and function as heat sinks. A mold support member may extend through a passage in the annular inner wall of the fluidized bed.

Abstract: An apparatus for use in casting a metal article includes a furnace assembly into which a mold is raised and a fluidized bed adjacent to the furnace assembly. The mold is filled with molten metal and lowered into the fluidized bed. The molten metal is solidified in the mold as it is lowered into the fluidized bed. The mold and fluidized bed are then lowered. The mold may be supported on a grid or support member having openings through which gas and particulate in the fluidized bed can flow. A stirrer member may be moved in the fluidized bed to promote uniform distribution of particulate in the flow of gas. Gas may be conducted from the support member for the mold into a container which holds the fluidized bed. Gas at different pressures may be conducted into the fluidized bed at different locations in the fluidized bed.

Abstract: An article, such as an airfoil, is cast by a lost wax investment casting process. The process includes providing a core having a configuration corresponding to the configuration of a space to be formed in the airfoil. The core is at least partially enclosed with a layer of wax. A portion of the layer of wax is removed from the core. The step of removing a portion of the layer of wax from the core includes heating a tubular member and melting a portion of the wax layer by engaging the wax layer with the heated tubular member. Molten wax is conducted away from the core through the heated tubular member. A mold is formed by at least partially coating the wax layer with mold material which extends across the core at the locations where the melted wax was conducted away from the core. The wax layer is removed to form a mold cavity which is filled with molten metal to cast the airfoil.

Abstract: To form a mold for casting a metal article, metal pins are inserted through a pattern. End portions of the metal pins are bent after the pins have been inserted through the pattern. The pattern and opposite end portions of the metal pins are then covered with wet ceramic mold material. A mold structure is formed by drying the wet ceramic mold material. The pattern is then removed from the mold structure to leave a mold cavity with the metal pins extending through the metal cavity between opposite side sections of the mold structure. Molten metal is conducted into the mold cavity and force is transmitted between opposite side sections of the mold structure through the metal pins to retard movement between the side sections of the mold structure. The molten metal is solidified in the mold cavity and a metallurgical bond is formed between the metal in the mold cavity and the metal pins. The cast article is then removed from the mold structure. The cast article has a thin wall section with a thickness of 0.

Abstract: An article has a thin wall portion with a thickness of 0.060 inches or less, a width of at least four inches, and a height of at least six inches. In order to cast the article, a pattern having a configuration corresponding to the configuration of the article is covered with a coating of wet ceramic material. In addition, a reinforcing pattern, which is spaced from the portion of the article pattern having a configuration corresponding to the thin wall portion of the article, is covered with the wet ceramic material. Space between the article pattern and reinforcing pattern is filled with the wet ceramic material. A combined mold structure and reinforcing structure are formed by drying the wet ceramic material. The article pattern is removed from the mold structure to leave a mold cavity. Molten metal is conducted into the mold cavity.

Abstract: A layer of hollow spheres is floated on a fluidized bed beneath a furnace. A mold containing molten metal is heated in the furnace to melt the molten metal. The mold is then moved from the furnace through the layer of hollow spheres into the fluidized bed. As the mold moves into the fluidized bed, heat is conducted form the mold and the metal is solidified.

Abstract: A wax article pattern having a cavity corresponding to a cavity in a metal article is provided. The cavity in the wax article pattern is filled with a slurry of ceramic core material. The slurry of ceramic core material is solidified to form a core. The wax article pattern is enclosed by ceramic mold material. The ceramic mold material is solidified to form a mold. The wax pattern is removed from the mold to leave an article mold cavity. The article mold cavity is filled with molten metal which is solidified to form the metal article. A passage in the metal article may be formed by a pin which extends from the wax article pattern into the cavity in the wax article pattern and is enclosed by the slurry of ceramic core material.

Abstract: An apparatus and method for use in casting a metal article includes a mold structure having wall sections with pins extending between the wall sections. The pins have opposite end portions which are embedded in the wall sections of the mold structure to interlock the pins and the wall sections of the mold structure. When molten metal is poured into the mold structure, the molten metal urges the wall sections away from each other. The wall sections are retained against movement relative to each other by the pins. Although the apparatus and method of the present invention can be utilized to cast many different types of articles, the invention is advantageously utilized in the casting of thin metal articles and specifically a thin metal article which is formed as a single crystal.

Abstract: An improved sintered ceramic core is used in a mold during the casting of a reactive metal. Prior to sintering, the core contains ceramic material which includes yttrium aluminate and alumina (Al.sub.2 O.sub.3). It is preferred to have the ceramic material contain between 10% and 40% yttrium aluminate. Prior to sintering, the yttrium aluminate has a mean particle size of less than 20 microns and, preferably, less than 10 microns. Particularly advantageous results has been obtained by using yttrium aluminate having a mean particle size, prior to sintering, of approximately 3 microns. It is contemplated that the ceramic material will be utilized to form other articles, such as a mold, filter, or liner for a ladle, which are exposed to reactive metals during casting.

Abstract: An improved sintered ceramic core is used in a mold during the casting of a reactive metal. Prior to sintering, the core contains ceramic material which includes yttrium aluminate and alumina (Al.sub.2 O.sub.3). It is preferred to have the ceramic material contain between 10% and 40% yttrium aluminate. Prior to sintering, the yttrium aluminate has a mean particle size of less than 20 microns and, preferably, less than 10 microns. Particularly advantageous results has been obtained by using yttrium aluminate having a mean particle size, prior to sintering, of approximately 3 microns. It is contemplated that the ceramic material will be utilized to form other articles, such as a mold, filter, or liner for a ladle, which are exposed to reactive metals during casting.

Abstract: An improved mold for use in casting a metal airfoil has an airfoil mold cavity and a starter chamber. A lower end of the starter chamber is formed by a chill plate. A filter is disposed in the starter chamber between the airfoil mold cavity and the chill plate. When an airfoil is to be cast, molten metal is conducted into the starter chamber, into passages in the filter and into the airfoil mold cavity. The molten metal is solidified upward in the starter chamber from the chill plate and through the passages in the filter. The filter blocks migration of impurities from the starter chamber to the airfoil mold cavity as the metal solidifies in the starter chamber. As the molten metal begins to solidify in the airfoil mold cavity, the molten metal is solidified as a large number of columnar grain crystals which extend from the passages in the filter into the airfoil mold cavity.

Abstract: To predict the rate of flow of cooling fluid (gas) through a passage system in a proposed airfoil during operation of a Jet engine, a full size model of the passage system is prepared. The flow of air or other gas is conducted through the model of the passage system. The characteristics of the flow of air or gas through the model of the passage system is determined to enable the characteristics of the flow of cooling fluid through the passage system in the proposed airfoil to be predicted. The model of the cooling fluid passage system in the proposed airfoil is formed by covering the pattern with a layer of metal. The pattern is removed from the covering to form a passage system having a configuration corresponding to the configuration of the cooling fluid passage system in the proposed airfoil.

Abstract: An improved binder is mixed with powder to form feedstock for molding. The binder includes a first component which is soluble in water and a second component which is insoluble in water. The two binder components are miscible with each other in a liquid state. The two binder components form a uniform heterogeneous mixture when mixed in a liquid state. The binder is mixed with a suitable powder to form the feedstock. The feedstock is molded to form a compact. Polymer units of the binder are cross linked after the compact has been formed. The cross linking of the polymer units of a component of the binder is accomplished by exposing the compact to ultraviolet radiation or by the use of a catalyst. The compact is partially debound by exposing the compact to water, that is, to a water based solvent. Thereafter, the compact is further debound to remove the component which is insoluble in water. The powder is then sintered to form an article.

Abstract: Reactive metals, such as titanium or nickel-chrome superalloys containing rare earths, are cast with mold and/or core surface areas formed from an improved slurry. The improved slurry contains yttria to form an inert surface which is exposed to the molten reactive metal. In order to prevent premature gelation of the slurry, the forming of defects in the mold and/or core surface areas, and the forming of defects in the cast article, the slurry contains a source of hydroxyl ions. The source of hydroxyl ions is sufficient to result in the slurry having a pH of at least 10.2 six days after initially mixing the slurry. The source of hydroxyl ions may be a metal alkali or an organic hydroxide. It is believed that the source of hydroxyl ions functions as a hydration suppressant for the yttria to prevent premature gelation of the slurry. The slurry contains a silicon oxide (SiO.sub.2) to alkali ratio which is equivalent to a silicon oxide to sodium oxide (Na.sub.

Abstract: A turbine engine component is made by forming a heat resistant layer on each airfoil of a plurality of airfoils. This heat resistant layer has a higher melting temperature than the melting temperature of material forming the airfoil. After heat resistant layers have been formed on the airfoils, a mold is formed around the airfoils. Molten metal is poured into the mold. The molten metal engages the heat resistant layers on the airfoils and solidifies to form a shroud ring. As the molten metal solidifies, slip joints between the solidified metal and end portions of the airfoils are free of bonds. The heat resistant layer is at least partially formed of chromium sesquioxide (Cr.sub.2 O.sub.3). A layer of chromium sesquioxide is formed by heating a nickel-chrome superalloy airfoil. As the airfoil is heated, the layer of metal immediately adjacent to the outer surface of the airfoil is depleted of chromium.

Abstract: A long thin metal article having a thick portion is cast with a stress free interconnection between the thick and thin portions of the article. A heat transfer wall is provided around at least a portion of a mold in which the article is cast. To preheat the mold, heat is radiated from an inner side surface of a furnace wall to an outer side surface of the heat transfer wall. Heat is radiated from an inner side surface of the wall to the mold. Molten metal is conducted into the long thin portion of the article mold at a location other than along the length of the long thin portion of the article mold. During solidification of the molten metal, heat is radiated from the thick portion of the article mold to the inner side surface of the heat transfer wall. As the mold structure is withdrawn from the furnace chamber during solidification of the molten metal in the article mold cavity, heat is radiated from the outer side surface of the heat transfer wall to locations outside of the furnace.