Westinghouse Electric Corporation

James E Smith

Gerald Joseph Bruck

Graham A Whitlow

Paul E Denney

Ronald D O'Brokta

Edmond E Conner

Near net shape metal articles are cast from powder feedstock using a focused high energy beam which melts successive layers of powder as it repetitively traces the shape of the article over a substrate without the necessity for refocusing. Powder is fed into a cavity in which the article is formed at a rate to maintain a depth which provides lateral support for, and therefore forms a mold for, a thick layer of powder which is melted by the energy beam to add each layer to the article. The high energy laser or electron beam has a power density sufficient to penetrate the melted layer of powder and melt the surface of the underlying substrate or layer just enough to provide a good metallurgical bond for the layer being added. A copper fixture which supports the substrate while the article is being formed, serves as a heat sink and forms the cavity which confines the powder to the vicinity of the article being formed. Various shapes can be cast through selected programming of the repetitive pattern of relative motion between the energy beam and the substrate.

Energy beam casting of metal articles

Virgin metal and metal alloy components are welded with and without filler material using a laser without cleaning the surfaces to be joined of mill scale and/or surface oxides, paints grease and other forms of contamination, and without edge preparation. The uncleaned, unprepared surfaces are placed in contact with each other, and a 100% through the thickness laser keyhole weld without filler metal is made in one pass, full penetration is achieved by two laser keyhole welds without filler metal (one made from each side), or resistively heated filler wire is fed into the metal pool of a laser conduction weld in one or more passes along each side of the confronting surfaces to be joined. Quality welds are made despite gaps of varying size up to about 0.125 inches between the parts to be joined.

Method of welding

A high voltage current transformer, and method of constructing same, including a primary winding having concentric leads, and a secondary winding on a magnetic core which is inductively linked with the primary winding. The magnetic core is a wound, two part core, with the two core parts being joined by stepped-lap joints. The secondary winding is a distributed winding having turns which are uniformly distributed about the complete magnetic circuit of the magnetic core. The conductor of the secondary winding is severed and the associated ends electrically re-connected, each time the conductor passes a stepped-lap joint.

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Delmont Boro, PA, United States of America

James E Smith