Abstract: A method of fabricating a machine component is provided. The method includes preparing at least a portion of a surface of a machine component for receiving a sintered preform. The method also includes forming a pre-sintered preform hybrid hardface mixture that includes combining a predetermined portion of at least one hardfacing material with a predetermined portion of at least one brazing material. The method further includes forming a pre-sintered preform. The pre-sintered preform has predetermined dimensions. The method also includes forming the sintered preform and positioning the sintered preform on the machine component. The method further includes fixedly coupling the sintered preform to at least a portion of the machine component via brazing.

Abstract: A method for stiffening a wind turbine tower employing fingerplate assemblies on flangeless joints between adjacent tubular tower sections. The method includes limiting the intercan gap between adjacent end surfaces of the tower sections at the flangeless joints and selecting a number of fingerplates to fasten each flangeless joints to limit distortion. Establishing dimensions for the fingerplates may further minimize localized tower distortion. Selecting a material for the fingerplate with a lower Young's modulus than a material for the tubular section also results in reduced localized tower distortion. Attaching a coverplate to a top tubular section limits tip displacement for the tower.

Abstract: A component for wind turbines includes cast austempered ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.06 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur. The component is preferably a drive shaft or gearbox component having a mass of more than about 3 tons. A method of manufacturing the component is also provided.

Abstract: A method for assembling a tower includes positioning a heated ring-shaped metal billet within a hot rolling mechanism. The hot rolling mechanism is rolled about at least a portion of the heated ring-shaped metal billet. At least a portion of the heated ring-shaped metal billet is removed, thereby at least partially forming a weld neck on the heated ring-shaped metal billet. The weld neck is welded to a tower can, thereby at least partially assembling a tower.

Abstract: A nacelle for a wind turbine generator includes a spaceframe having at least one exterior panel and at least one interior panel joined to the exterior panel. Each of the exterior and interior panels have a plurality of generally U-shaped channel portions with flanges extending outward from the channel portion. The flanges of the exterior panel are joined to the flanges of the interior panel to define a plurality of ribs, a plurality of joints, and a plurality of openings.

Abstract: Embodiments of the present disclosure include a system for creating a lattice type structure using friction forge bonds to connect the tower members. The system includes a rotary actuator for engaging and rotating a fastener to create frictional heat at a forge interface between the fastener and two or more workpieces. The system also includes a press that forces the fastener against the workpieces to be bonded, and a heater that may provide additional heating of the fastener and the opening.

Abstract: Slip ring assemblies for controlling pitch of a wind driven blade such as those utilized in wind turbines can include a series of grooves disposed about an outer perimeter of a rotating portion, each one of the grooves comprising a first planar surface intersecting with a second planar surface at an angle of 75 to 105 degrees, and a concavely rounded bottom portion at the intersection of the first and planar surfaces. The rotating portion of the slip ring can be formed of a bronze material and may include a graphite coating. Also disclosed herein are wind turbine assemblies employing the slip ring assemblies.

Abstract: A method of assembling a wind turbine generator includes fabricating a first portion of a shaft from a first steel alloy having a first strength property value. The method also includes fabricating a second portion of the shaft from a second steel alloy having a second strength property value. The first strength property value is greater than the second strength property value. The method further includes welding the second portion of the shaft to the first portion of the shaft.

Abstract: A wind turbine and method for assembling a wind turbine is provided. The wind turbine is configured to stand on a foundation, and the wind turbine assembly includes a tower and an elevated tower foundation. The elevated tower foundation has multiple support members having a plurality of main support members and a plurality of bracing members. The bracing members are connected to the main support members. The tower is mounted on the elevated tower foundation.

Abstract: Embodiments of methods and apparatus for welding are provided. According to one embodiment, an apparatus may include a torch body supporting an electrode at least partially extending from the torch body, the electrode having a longitudinal central axis therethrough. The apparatus may also include a heat transfer block spaced apart from the electrode and at least partially intersecting the longitudinal central axis. An electric arc may be generated between the electrode and the heat transfer block.

Abstract: A method for stiffening a wind turbine tower employing fingerplate assemblies on flangeless joints between adjacent tubular tower sections. The method includes limiting the intercan gap between adjacent end surfaces of the tower sections at the flangeless joints and selecting a number of fingerplates to fasten each flangeless joints to limit distortion. Establishing dimensions for the fingerplates may further minimize localized tower distortion. Selecting a material for the fingerplate with a lower Young's modulus than a material for the tubular section also results in reduced localized tower distortion. Attaching a coverplate to a top tubular section limits tip displacement for the tower.

Abstract: An article as disclosed herein comprises a steel comprising carbon in an amount greater than 0.18 weight percent and less than or equal to 0.23 weight percent by ladle analysis, wherein a test article consisting of the steel has a low temperature Charpy V-notch toughness of greater than or equal to 54 Joules when measured at ?40° C. according to ASTM E23-01, and wherein a test article consisting of the steel further meets the other test requirements for S355NL steel according to European Norm EN 10 113-2:1993. In an embodiment, the article is a flange for a wind tower, and is suitable for use under extremely cold operating conditions (to ?30° C.). A method for forming the flange is also disclosed.

Abstract: A washer, including a body having a first face, a second face, and an aperture extending through the body from the first face to the second face, and a plurality of protrusions extending from at least one of the first face and the second face. The plurality of the protrusions have sufficient structural integrity to create a plurality of corresponding deformations in a separate mating surface during compressive loading of the washer against the separate mating surface.

Abstract: A process for repairing a turbine component of a turbomachine, as well as a sintered preform used in the process and a high gamma-prime nickel-base superalloy component repaired thereby. The sintered preform contains a sintered mixture of powders of a cobalt-base braze alloy and a cobalt-base wear-resistant alloy. The braze alloy constitutes at least about 10 up to about 35 weight percent of the sintered preform and contains a melting point depressant such as boron. The preform is formed by mixing powders of the braze and wear-resistant alloys to form a powder mixture, and then sintering the powder mixture. To use the preform, a surface portion of the turbine component is removed to expose a subsurface portion, followed by diffusion bonding of the preform to the subsurface portion to form a wear-resistant repair material containing the braze alloy dispersed in a matrix of the wear-resistant alloy.

Abstract: Slip ring assemblies for controlling pitch of a wind driven blade such as those utilized in wind turbines can include a series of grooves disposed about an outer perimeter of a rotating portion, each one of the grooves comprising a first planar surface intersecting with a second planar surface at an angle of 75 to 105 degrees, and a concavely rounded bottom portion at the intersection of the first and planar surfaces. The rotating portion of the slip ring can be formed of a bronze material and may include a graphite coating. Also disclosed herein are wind turbine assemblies employing the slip ring assemblies.

Abstract: A cobalt-based braze alloy composition comprises: 22 to 24.75% chromium by weight; 9 to 11% nickel by weight; 6.5 to 7.6% tungsten by weight; 3 to 4% tantalum by weight; 0.55 to 0.65% carbon by weight; 0.3 to 0.6% zirconium by weight; 0.15 to 0.3% titanium by weight; 1.5 to 2.6% boron by weight; 1 to 10% silicon by weight; and cobalt. There are also provided methods of using the same.

Abstract: A weld repair method uses a gas tungsten or plasma arc welding torch and matching filler. An amperage supplied to the torch and a travel speed of the torch are controlled to produce a weld bead having a mushroom shape. The weld bead is ground from all sides to remove at least one half of a thickness of the weld bead, and another weld bead is formed. The technique produces crack free welds with directionally solidified weld metal that is similar to that of the base material and hence has comparable mechanical properties.

Abstract: A process for repairing a turbine component of a turbomachine, as well as a sintered preform used in the process and a high gamma-prime nickel-base superalloy component repaired thereby. The sintered preform contains a sintered mixture of powders of a cobalt-base braze alloy and a cobalt-base wear-resistant alloy. The braze alloy constitutes at least about 10 up to about 35 weight percent of the sintered preform and contains a melting point depressant such as boron. The preform is formed by mixing powders of the braze and wear-resistant alloys to form a powder mixture, and then sintering the powder mixture. To use the preform, a surface portion of the turbine component is removed to expose a subsurface portion, followed by diffusion bonding of the preform to the subsurface portion to form a wear-resistant repair material containing the braze alloy dispersed in a matrix of the wear-resistant alloy.

Abstract: A process for repairing a turbine component of a turbomachine, as well as a sintered preform used in the process and a high-gamma-prime nickel-base superalloy component repaired thereby. The sintered preform contains a sintered mixture of powders of a cobalt-base braze alloy and a cobalt-base wear-resistant alloy. The braze alloy constitutes at least about 10 up to about 35 weight percent of the sintered preform and contains a melting point depressant such as boron. The preform is formed by mixing powders of the braze and wear-resistant alloys to form a powder mixture, and then sintering the powder mixture. To use the preform, a surface portion of the turbine component is removed to expose a subsurface portion, followed by diffusion bonding of the preform to the subsurface portion to form a wear-resistant repair material containing the braze alloy dispersed in a matrix of the wear-resistant alloy.

Abstract: A process for repairing a turbine component of a turbomachine, as well as a sintered preform used in the process and a high gamma-prime nickel-base superalloy component repaired thereby. The sintered preform contains a sintered mixture of powders of a cobalt-base braze alloy and a cobalt-base wear-resistant alloy. The braze alloy constitutes at least about 10 up to about 35 weight percent of the sintered preform and contains a melting point depressant such as boron. The preform is formed by mixing powders of the braze and wear-resistant alloys to form a powder mixture, and then sintering the powder mixture. To use the preform, a surface portion of the turbine component is removed to expose a subsurface portion, followed by diffusion bonding of the preform to the subsurface portion to form a wear-resistant repair material containing the braze alloy dispersed in a matrix of the wear-resistant alloy.