Avco Corporation

Jack W Lee

Jule A Miller

Michael A Iovene

Roman T Kowalski

John L Fritz

Jeffrey Thyssen

A method of repairing damages in a superalloy component is disclosed wherein existing brazed joints and protective coatings are not harmed. The method entails the use of a silicon-free metal mixture comprising (i) a low melting alloy having a liquidus below the temperature to be used to deposit the metal mixture, (ii) an alloy melting above about 2100.degree. F., and (iii) optionally nickel. The resultant repair has a solidus temperature of at least 1950.degree. F., preferably at least 2000.degree..

Method of repairing damages in superalloys

A welding head 10 for coupling a welding electrode 12 to a source of electrical current. The welding head includes a housing 30 and an electrically conductive shaft 18 rotatably mounted with the housing. The shaft has a substantially circular cylindrical shape having a first end surface for mounting a welding electrode thereto and a second, substantially flat, opposing end surface 20. The welding head further includes an electrical coupler in contact with the second substantially flat end surface of the shaft for coupling electrical current into the shaft. The electrical coupler includes an electrical conductor having a first end coupled to a source of welding power and an electrically conductive contact plate 22 having a substantially flat surface in contact with the second substantially flat end surface of the shaft. In one embodiment of the invention the shaft rotates against the plate upon the second end opposing surface while in another embodiment of the invention the contact plate is rigidly coupled to the shaft end. In the embodiment wherein the shaft rotates agains the contact plate an input lubricant flow coupler and an output lubricant flow orifice provide lubrication to the rotating electrical contact surface. An input cooling flow coupler and an output cooling flow coupler are also included for providing for a flow of a cooling medium for cooling the contact plate during the operation thereof.

Resistance welding head

A silicon-free metal powder mixture suitable for filling holes, slots and widegap joints in high temperature superalloys and/or for reforming damaged or missing surface extensions thereof, and capable of being processed at a temperature of about 2000.degree. F. The semi-solid metal mixture has a sufficiently high surface tension and viscosity to be essentially non-flowing at the processing temperature so that it retains its applied shape and location without flowing during processing. The metal mixture after processing has a solidus temperature of at least 1950.degree. F.

High temperature metal alloy mixtures for filling holes and repairing

A method is disclosed for the removal of undesirable oxides from the surface of nickel-base or nickel-iron base alloys containing oxidizable aluminum and/or titanium prior to brazing. The alloy is heated in air at an elevated temperature for a time sufficient to form on the alloy surface a bilayered film comprised of a first oxide top layer containing at least titanium or aluminum and a second layer beneath the first comprised of the alloy composition substantially depleted of aluminum and/or titanium. The surface of the alloy is cleaned to remove the first oxide layer whereupon the remaining surface is in condition for brazing.

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Brookfield, CT, United States of America

Jack W Lee