Centrifugal casting of nickel base superalloys in isotropic graphite molds under vacuum
AssigneeSantoku America, Inc.
InventorsRanjan Ray, Donald W. Scott
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Abstract
Methods for making various nickel based superalloys into engineering components such as rings, tubes and pipes by melting of the alloys in a vacuum or under a low partial pressure of inert gas and subsequent centrifugal casting of the melt in the graphite molds rotating along its own axis under vacuum or low partial pressure of inert gas are provided. The molds have been fabricated by machining high density, high strength ultrafine grained isotropic graphite, wherein the graphite has been made by isostatic pressing or vibrational molding.
Claims12
A method of making cast shapes such as rings, tubes and pipes with smooth or contoured profiles on the outside diameter of nickel base superalloys, comprising the steps of:
- melting the alloy under vacuum or partial pressure of inert gas;
- pouring the alloy into a cylindrical mold rotating around its own axis, wherein the mold is made of machined graphite, wherein the graphite has been isostatically or vibrationally molded and has ultra fine isotropic grains between 3-40 micron, a density between 1.65 and 1.9 grams/cc, flexural strength between 5,500 and 20,000 psi, compressive strength between 9,000 and 35,000 psi, and porosity below 15%;
- and
- solidifying the melted alloy into a solid body taking the shape of the mold cavity.
A centrifugal casting apparatus for casting metal products comprising, an isotropic graphite mold, and means for rotating the isotropic graphite mold.
Dependencies are inferred from the claim text.