Westinghouse Electric Corporation

Samuel D Reynolds, Jr

Homer G Hargrove

Stanley S Sagan

Angelo R Giardina

James C Dunmire

Ashoke K Mukherjee

Narayana S Cheruvu

A method for metallurgical enhancement of a failed bolt hole, or stud attachment, providing for replacement of service induced failed material from the female threaded area of the bolt hole. A method in accordance with the present invention is particularly suited for power plant equipment, such as a steam turbine. Failed material from the female threaded area is removed and filler metal is arc welded to the exposed base metal of the hole using a mechanized gas tungsten arc weld device employing a continuous spiral weld bead. Proper selection of the filler metal, considering the base metal to which it is applied and, moreover, the type of failure which the base metal of the hole has been experiencing, provides for improved structural integrity of the mechanical joint and increased service life of the associated steam turbine apparatus. Weld tempering of the filler metal reduces undesirable weakening of the weld metal in the heat affected zone, thus providing further metallurgical enhancement of the failed bolt hole.

Method for metallurgical enhancement of a failed bolt hole

Methods for fabricating and repairing heat exchange tubing are provided including depositing an integral solderable coating onto a surface oxide of a tubular member and then soldering a plurality of spaced fins onto the integral solderable coating. The methods described herein provide economical techniques for fabricating heat exchange tubing suitable for use in extremely corrosive environments.

Method for improving the solderability of corrosion resistant heat

Methods for providing erosion resistant surfaces to carbon steel turbine components are provided by this invention. The methods include welding a steel weldment comprising at least 12 wt. % Cr. on to a carbon steel steam turbine component at a welding speed of about 24-52 inches, 61-132 cm, per minute in a nominal first pass thickness of less than about 0.1 inches, 0.25 cm. Preferred flux-cord-arc welding (FCAW) techniques are disclosed for vertical down, overhead, horizontal and flat surfacing positions.

Steam turbine having applied novel erosion resistant surfaces and

A method of stud welding stainless steel studs to carbon steel or low alloy steel components with formation of a ductile weld therebetween. The chromium equivalent and nickel equivalent of the steel component is determined and a stainless steel stud provided that has a chromium equivalent and nickel equivalent content which, upon dilution thereof by steel of the component during stud welding, will provide a structure of austenite plus ferrite in the resulting weld structure, and stud welding the specified stainless steel stud to the steel component.

Method of welding stainless steel studs

An improved steam turbine system is provided having a hardfacing disposed on a portion of its steam inlet chamber wear surfaces. The invention also includes a novel stacked ring design having a hardfaced inlet sleeve and stationary, nitride sealing rings for minimizing wear. Also included are novel heat treatments and metallurgical processes for stress relieving these hardfaced components. The techniques and designs employed, decrease steam leakage and assure longer service life for steam powered turbines.

Hardfacing technique and improved construction for inlet steam sealing

A tube to composite tubesheet connection system for preventing fluid leakage from the shell to the tube side and from the tube side to the shell side of a shell and tube heat exchanger. Tubes are inserted through and fastened to an inner tubesheet structure. An outer tubesheet structure constituting a plurality of outer tubesheet covers cooperates with the tubes which protrude therethrough and with the inner tubesheet to form a plurality of cavities. The inter-tubesheet cavities about each row or column of tubes are interconnected in a variety of ways. Grooving at least one of the tubesheet structures about its tube holes provides groove-cavities which may be selectively interconnected by networks of holes formed in at least one of the tubesheet structures. Additional cavity interconnection systems include outer tubesheet covers grouped together in sets of cover strips which enclose furrows formed between selected cavities in the outer surface of the inner tubesheet and metallurgically partially refilled portions of a plurality of channels formed between selected cavities in the outer surface of the inner tubesheet. Cavities may also be provided by assembling concave or channel-shaped outer tubesheet covers with the tubes and the inner tubesheet structure. Such cavities must be interconnected by a plurality of hole networks primarily concealed within the inner tubesheet but which connect selected cavities. A final technique for selectively connecting the inter-tubesheet cavities is grooving at least one of the tubesheet structures about the tube holes so as to cause the grooves to intersect and thus connect, or more correctly, form the cavities. The aforementioned grooving connection, however, requires nonstandard tube pitches to limit the interconnections to predetermined, localized areas which facilitate isolation of tube leaks to such predetermined areas as single rows or columns of tubes.

Growing community of inventors

Oviedo, FL, United States of America

Samuel D Reynolds, Jr