Pcc Airfoils, Inc.

Harold L Wheaton

Lawrence Donald Graham

William S Blazek

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 0.060 inches or less. The metal pins have cylindrical outer side surfaces with a diameter of 0.030 inches or less.

Apparatus and method for casting a metal article

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. Force is transmitted from the mold structure to the reinforcing structure to prevent deformation of the mold structure under the influence of force applied against the mold structure by the molten metal.

Method of casting a thin wall

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.

Method of casting an article

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.

Apparatus and method for molding an article

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. This results in the formation of an outer layer of chromium sesquioxide and an inner layer from which the chromium has been depleted. Both layers have a higher melting temperature than the melting temperature of the material forming the airfoil.

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Bowerston, OH, United States of America

Harold L Wheaton