Friction surfacing—A review

A method of repairing a turbine blade (10) which includes performing a heating operation on the blade (10) in which the blade is heated to achieve a predetermined temperature distribution, sensing the temperature of the blade at least at one position by temperature sensing means (57-63) and controlling the application of heat in accordance with the temperature determined by said at least one sensing means and monitoring the temperature of the blade at a location adjacent said at least one position with a monitoring means (57a-63a).

Turbine blade repair

A method for replacing airfoil components includes the steps of identifying a portion of the airfoil to be replaced, removing the portion by a nonconventional machining process, such as continuous wire electrical discharge machining, and forming a replacement member utilizing a similar cutting process. A cutting path utilized to remove the portion to be replaced and to form the replacement member includes interlocking projections and sockets and may include one or more tapers along the cutting path so that the portion may be removed only by lifting in one direction. In cases where an entire airfoil is replaced, a first projection may be tapered in one direction while a second projection is tapered in an opposite direction so that the airfoil may not be removed as long as its adjacent flowpath walls are fixed relative to one another. Gas bending load dampers and zero gap standoffs may also be included for precision alignment of the replacement member and further securement of the replacement member in the airfoil.

Method of making replacement airfoil components

Damage in a blisk airfoil is machined away to create a notch. A repair is welded in the airfoil to fill the notch. The weld repair is then machined to restore the airfoil to a substantially original, pre-damaged configuration at the repair.

Blisk weld repair

The invention relates to a method for forming a three-dimensional article through successive fusion of locations of a powder bed. The method comprising: providing a model of said three-dimensional article; applying a powder layer on a work table; determining a maximum scan length of an energy beam; directing said energy beam from a first energy beam source over said work table with constant energy causing said first powder layer to fuse in first selected locations according to said model to form a first cross section of said three-dimensional article, wherein locations with a shorter scan length than said maximum scan length is provided with a time sink before and/or after said scan line so that the time period between each two adjacent scan lines is constant throughout the manufacture of said three-dimensional article.

Method for additive manufacturing

System for repairing worn surfaces of steam turbine components and especially high pressure turbine rotors, are disclosed. These systems include depositing a first layer of weld metal on a worn surface of the component, whereby a heat-affected zone is created. A second layer of weld metal is then deposited over the first layer using a greater amount of heat to temper at least a portion of the heat-affected zone produced by the first layer. The preferred embodiments include the use of gas tungsten arc welding for providing fine-grain size and more creep resistance, especially in the weld and heat-affected zone. The resulting build-up can be machined, for example into a blade fastening to produce a component having properties equal to or better than the base-metal alloy. The invention also provides a longer lasting turbine system, including rotors which have serrated steeples that are more resistant to failure.

Turbine system having more failure resistant rotors and repair welding of low alloy ferrous turbine components by controlled weld build-up

A more creep resistant turbine rotor and novel methods for repairing worn surfaces of Cr-Mo-V steam turbine components are disclosed. These methods include specified alloy compositions and welding procedures that minimize weld stresses and cracking. These alloys exhibit improved creep and fatigue properties and are preferably deposited using a gas tungsten arc welding procedure. Bead sequencing, cooling side plates and the use of run-off tabs are also disclosed for minimizing welding defects in turbine rotors and discs.

More creep resistant turbine rotor, and procedures for repair welding of low alloy ferrous turbine components

This is a method for repairing low alloy steel steam turbine (both high pressure and low pressure sections) or generator rotors. The defective section of the original rotor is removed and a replacement end is used, with mating attachments machined on the replacement end and the original rotor. The inner portion of the weld joining the replacement end to the original rotor is provided by a narrow gap weld, either by gas metal or by submerged arc welding. The outer 1/2-2 inches of the weld is provided by gas tungsten arc welding. The mating attachment and at least the inside 1/4 inch of the weld is bored out to remove possible crack initiation sites and to provide a smooth inspectable bore. In this manner, a fast and reliable technique is provided which provides accurate alignment, fast, essentially distortion free welding, and the superior mechanical properties of gas tungsten arc welding in the outer, more highly stressed zones.

Method for repairing a steam turbine or generator rotor

A turbine rotor is formed from two rotor segments that are composed of different low alloy steels, one a high temperature alloy and the other a low temperature alloy. The rotor segments have cavities in confronting faces that form an annular flange at the outer surface, with the segments welded together across the flange. A clad layer is first welded on one of the flanges and a filler material welds the clad layer to the other flange to form a composite turbine rotor.

Method of making a high temperature - low temperature rotor for turbines

This invention relates to an improved method for repairing damaged or worn surfaces of turbine components or upgrading older designs to new, improved designs. This improved method applies to both high pressure and low pressure turbine components applications. This method includes depositing a plurality of individual spaced apart weld volumes (11, 13, 15, 17) onto a prepared surface (3) of a turbine rotor (5). These individual spaced apart weld volumes (11, 13, 15, 17) form individual fingers (12, 14, 16, 18) without the need to machine the individual fingers (12, 14, 16, 18) from a single rectangular weld volume. Multiple weld volumes (11, 13, 15, 17) are formed concurrently with a space (19) maintain between each weld volume (11, 13, 15, 17) using multiple torches (21, 23) without the problems normally associated with closely spaced welding arcs. Each individual spaced apart weld volume (11, 13, 15, 17) is formed by a plurality of layers (29) of weld metal (27), with each layer (29) being formed from a single oscillating weld bead (28) to form a predetermined width (W). The filler wire weld metal (27) may be heated by applying a current (25) through the filler wire (27) before it is fed into the weld pool. Welding parameters are also changed to increase the amount of weld deposition without adversely affecting the mechanical weld properties. The invention provides for reduced cycle time for repair work by using multiple torches (21, 23) simultaneously without causing arc instability. The invention also reduces cycle time, by eliminating the need of machining individual fingers on control stages from a single weld volume, by changing the weld buildup of multiple projections (11, 13, 15, 17), slightly larger than the fingers (12, 14, 16, 18) which hold the blades.

Dennis Ray Amos

Papers

Turbine system having more failure resistant rotors and repair welding of low alloy ferrous turbine components by controlled weld build-up

More creep resistant turbine rotor, and procedures for repair welding of low alloy ferrous turbine components

Method for repairing a steam turbine or generator rotor

Method of making a high temperature - low temperature rotor for turbines

Turbine rotor modernization and repair method