Abstract: A method for weld repairing an article formed of a low-alloy steel, such as a steam turbine component. The method generally includes the step of depositing a first weld repair (14) on a surface of the article, during which a hard heat-affected zone (HAZ) (18) having a fine grain size is formed in the article beneath the surface on which the weld repair (14) is deposited. The first weld repair (14) and at least a portion of the HAZ (18) adjacent the first weld repair (14) are then locally heat treated at a temperature above a critical temperature A.sub.1 of the alloy from which the article is formed. As a result of this localized heat treatment, the original grain structures of the first weld repair (14) and the HAZ (18) are entirely replaced with a fine-grain structure with acceptable hardness. Thereafter, at least one additional weld repair layer (16) is deposited on the first weld repair (14).
Type:
Grant
Filed:
March 25, 1998
Date of Patent:
September 12, 2000
Assignee:
General Electric Co.
Inventors:
Gerald Richard Crawmer, John Francis Nolan
Abstract: A high voltage generator armature bar (10) that exhibits improved performance by forming one or more of its conductive components from a conductive material that uses a tin oxide-based composition as a conductive filler. The armature bar (10) is of the type having one or more tiers of conductor strands (12), strand insulation (14), conductive internal grading (20), groundwall insulation (22), conductive slot armoring (24), and preferably a transposition filler (18). The conductive internal grading (20), the conductive slot armoring (24) and/or the transposition filler (18) contain a conductive filler of antimony-doped tin oxide that may constitute the entire conductive filler, or can be present as a shell on the filler particles.
Type:
Grant
Filed:
August 19, 1998
Date of Patent:
March 28, 2000
Assignee:
General Electric Co.
Inventors:
Mark Markovitz, James Jonathan Grant, Jeffrey David Sheaffer, William Edward Tomak
Abstract: A braze material for repairing an article, and particularly industrial gas turbine engine nozzles formed from nickel-base superalloys. The braze material is composed of a nickel-base braze alloy that is preferably in powder form and dispersed in a suitable vehicle, such as a binder that forms a slurry with the powder. The braze alloy is formulated to be capable of withstanding the high temperature operating environment of an industrial gas turbine nozzle, and to have a melting temperature below the recrystallization temperature of the superalloy to be repaired. A desirable composition for the braze alloy, in weight percent, about 14 to 24 chromium, about 6 to 15 cobalt, about 0.7 to 2.5 boron, about 1.0 to 2.0 titanium, about 0.6 to 1.0 aluminum, about 1.0 to 1.4 tungsten, about 0.4 to 0.6 columbium, about 0.5 to 0.7 tantalum, and up to about 0.7 iron, with the balance being nickel and incidental impurities.
Abstract: A spray tower for removing acidic gases and particulate matter from flue gases produced by processing operations of the type carried out in utility and industrial facilities. The spray tower is equipped with a tank that serves as a reservoir for an alkaline slurry used to remove acidic gases and particulate matter from the flue gases. The slurry is pumped from the tank to spraying devices located within the tower. The spray tower further includes an internal structure that enables the slurry to be oxidized and gently agitated within a limited region of the tank, and without the requirement for two separate aeration and agitation devices. As a result, the construction, operational and maintenance costs of the spray tower are significantly reduced as compared to prior art spray towers.