United Technologies Corporation

Stephen Douglas Murray

James Thompson Beals

Carl R Verner

Jacob A Snyder

Brandon W Spangler

Samuel D Draper

Michael K Turkington

Jose A Lopes

John Joseph Marcin

Keith A Santeler

Lea D Kennard

Maria Arceo Herring

Bryan P Dube

John J Marcin

Joshua E Persky

Reade R Clemens

Delwyn E Norton

Donald D Schofield

Richard L Ritchie

Steven J Bullied

Dilip M Shah

Daniel A Bales

Dinesh K Gupta

Sudhangshu Bose

Daniel F Paulonis

Glenn A Cotnoir

John D Wiedemer

Keith Douglas Sheffler

Dilip N Shah

W Samuel Krotzer, Jr

Venkat Seetharaman

Dawn D Mandich

Michael T Turkington

A refractory metal core for use in a casting system has a coating for providing oxidation resistance during shell fire and protection against reaction/dissolution during casting. In a first embodiment, the coating includes at least one oxide and a silicon containing material. In a second embodiment, the coating includes an oxide selected from the group of calcia, magnesia, alumina, zirconia, chromia, yttria, silica, hafnia, and mixtures thereof. In a third embodiment, the coating includes a nitride selected from the group of silicon nitride, sialon, titanium nitride, and mixtures thereof. Other coating embodiments are described in the disclosure.

Refractory metal core coatings

In accordance with the present invention, a casting system is provided which broadly comprises a core and a wax die spaced from said core, a refractory metal core having a first end seated within a slot in the core and a second end contacting the wax die for positioning the core relative to the wax die, and the refractory metal core having at least one of a mechanism for providing spring loading when closed in the wax die and a mechanism for mechanically locking the wax die to the core.

Refractory metal core wall thickness control

A sacrificial core is used for forming an interior space of a part and includes a ceramic core element and a first core element including a refractory metal element. The ceramic core element may be molded over the first core element or molded with assembly features permitting assembly with the first core element.

Investment casting core methods

Pre-molding of wax or similar sacrificial material over one or more cores facilitates a subsequent molding over a core assembly. Individual cores or groups thereof may be pre-molded in a wax body. One or more such wax bodies may be assembled with other bodies and/or other cores to facilitate a main wax molding of such assembly.

Investment casting

A method and apparatus are used to cast a number of elements such as turbine engine blades. The blades have an airfoil and a root for securing the blade to a disk. A number of mold sections each have internal surfaces for forming an associated at least one of the elements. The mold sections are assembled and molten alloy is introduced to the assembled mold sections.

An apparatus for shelling an investment casting pattern has a tank containing a coating material. There are means for holding the pattern immersed in the coating material. There may be means for vibrating the pattern during immersion of the pattern and a vacuum source coupled to the tank to withdraw air from at least one headspace of the tank.

Shelling apparatus and methods for investment casting

An at least two step heating process is used to strengthen the shell of an investment casting mold including a refractory metal core. The first stage may occur under otherwise oxidizing conditions at a low enough temperature to avoid substantial core oxidation. The second stage may occur under essentially non-oxidizing conditions at a higher temperature.

Methods for manufacturing investment casting shells

A sacrificial core for forming an interior space of a part includes a ceramic core element and a first core element including a refractory metal element. The ceramic core element may be molded over the first core element or molded with assembly features permitting assembly with the first core element.

Investment casting cores

Concepts for fabricating improved cores for investment casting are described. The cores are composite which include refractory metal elements and ceramic elements. The refractory metal elements are provided to enhance the mechanical properties of the core and/or to permit the fabrication of cores having shapes and geometries that could not otherwise be achieved. In one embodiment, the entire core may be made of refractory metal components. The cores may be used to investment cast gas turbine superalloy components.

Cores for use in precision investment casting

The invention is a process for removing ceramic thermal barrier layers from gas turbine engine hardware. A combination of chemical and mechanical steps are used to remove the thermal barrier coating from the substrate without removing the bond coat from the substrate. The process leaves the bond coat on the substrate in condition to receive a repair ceramic thermal barrier coating. The process includes a caustic solution treatment in an autoclave under controlled conditions followed by a mechanical abrasion process.

Thermal barrier removal process

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Marlborough, CT, United States of America

Stephen Douglas Murray