Patent Application
20180250762
The present disclosure is directed to processes for preparing a component part for processing, the part being, in some examples a metal part, and in some particular examples a superalloy part. More specifically, the present embodiments are directed to processes for deep penetration within a gap (crevice or crack) for removal of contaminates, including, oxides, dirt, grease and other debris, prior to crack processing, for example, processing by one or more of brazing and narrow gap welding.
During operational use, machine components experience exposure to severe working environmental conditions, and material degradation will occur due to fatigue, creep, corrosion or oxidization. This is particularly the case with turbine engine parts formed of superalloy materials, which are susceptible to damage from erosion, oxidation, and attack from environmental contaminants.
Processing of in service turbine engine parts involves cleaning cracks and crevices, and other surfaces so to remove oxides, organic and inorganic impurities, and dirt prior to other processes, such as brazing and narrow gap welding, among others. Fluoride ion cleaning (FIC) or etching is commonly used to clean the surfaces of engine parts, including shallow cracks. However, cracks and crevices present unique challenges with respect to removal of contaminates and debris. In particular, crack depth and morphology can impede thorough crack preparation by common mechanical and chemical processing methods such as FIC. Insufficient removal of contaminants leads to incomplete gap processing, and residual oxides and other contaminants within a crack or crevice can lead to premature failure of a part. Alternatives to cleaning exist that involve removal of portions of the part in order to optimize processing, however, material removal also introduces material weakness that can adversely affect the useful life of a part.
In an exemplary embodiment, a process for treating a narrow gap in a component part includes characterizing the gap and treating it to remove debris and oxidation using a pressurized water jet. The process includes the step of capturing a digital image of a gap in a portion of a component, the gap characterized as having gap walls, a length, and at any point along its length, having the features of an inner width between the gap walls, an outer width between the gap walls, and a depth. The process further includes the steps of measuring one or more of such features at one or more points along all or a portion of the length of the gap, and the further steps of determining a water jet cleaning path, and determining a water jet cleaning edge relative to a gap wall, and determining a water jet cleaning path angle. The process further includes the step of passing a water jet along all or a portion of the selected path to remove debris and/or a portion of a gap wall. The process further includes processing the treated gap to join the gap edges using a suitable sealing method.
Other features and advantages of the present invention will be apparent from the following more detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
The detailed description set forth below in connection with the appended drawings where like numerals reference like elements is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed.
All numbers expressing quantities of ingredients and/or reaction conditions are to be understood as being modified in all instances by the term “about”, unless otherwise indicated.
All percentages and ratios are calculated by weight unless otherwise indicated. All percentages are calculated based on the total weight of a composition unless otherwise indicated. All component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources.
The articles “a” and “an,” as used herein, mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of “a” and “an” does not limit the meaning to a single feature unless such a limit is specifically stated. The article “the” preceding singular or plural nouns or noun terms denotes a particular specified feature or particular specified features and may have a singular or plural connotation depending upon the context in which it is used. The adjective “any” means one, some, or all indiscriminately of whatever quantity.
A “gap,” as that term is used herein, refers to any void volume, such as, for example, a crack, fissure, crevice, or aperture within a part, in particular, having a gap distance between opposing surfaces small enough such that the gap does not permit adequate penetration with conventional chemical and mechanical cleaning processes such that materials on the surface within the gap, such as oxides and other contaminants, cannot be removed from the defect using conventional processes.
“Brazing,” as used herein, refers to what is conventionally known as a metal joining process in which metal portions, such as parts, are joined together, or gaps are filled/closed, by melting and flowing a filler metal into a joint or gap, the filler metal having a lower melting point than the adjoining metal. In some embodiments, brazing is used in a gas turbine power generation parts. In some embodiments, brazing is used in a stainless steel alloy, a nickel-based superalloy, and/or a cobalt-based superalloy.
The term “water jet cleaning,” as used herein, refers to cleaning a material using a pressurized stream of water, with or without the inclusion of abrasives in the water stream. A water jet is an industrial tool to cut a wide variety of materials using a very high-pressure jet of water directed through a jet nozzle, wherein the nozzle travels along a path that may be linear, curved or irregular, the angular orientation of the nozzle being fixed or variably angled along the path, the path typically being directed by a computer program based on a predetermined path that is mapped relative to the component and controlled by an image analysis tracing system. As used for purposes of the instant disclosure, “cleaning” means and includes removal of material or debris using, in some embodiments, a water jet that may be sufficiently pressurized to cut the base material of the part, and, in other embodiments, using a water out stream that is not highly pressurized so that it only removes superficial debris but does not cut the base material of the part. In some embodiments, processing of a part may include combinations of these along a gap or on more than one gap in a treated portion of a part.
The term “imaging” means and includes any one or more imaging modality selected from conventional digital photography, X-ray, CT and UT.
The present invention includes, in various embodiments, processes for gap cleaning to provide the part with enhanced defect preparation and repair. In some embodiments, the cleaning constitutes water jet cleaning of at least a portion of a gap whereby one or more of surface contamination and/or oxidation and a portion of the part within and/or adjacent to the gap is removed by water jet cleaning. The processes hereof are particularly suited for parts and hardware used for power generation equipment, including gas turbines. Examples of a turbine part include a turbine blade, vane, bucket, nozzle, and the like.
The processes according to the present disclosure may effectively enable structural repair of hard-to-weld superalloy, and minimize the amount of base material of the part that must be removed, and thus confer optimal mechanical properties to the repaired part. In some embodiments, a repaired part herein illustrated may comprise a metal or an alloy. The alloy may comprise a superalloy. The term “superalloy” is used herein as it is commonly used in the art; i.e., a highly corrosion and oxidation resistant alloy that exhibits excellent mechanical strength and resistance to creep at high temperatures.
In some embodiments, the component may include, but not be limited to, a single crystal (SX) material, a directionally solidified (DS) material, an equiaxed crystal (EX) material, and combinations thereof.
In some embodiments, the superalloy may include nickel-based superalloy, cobalt-based superalloy, iron-based superalloy, titanium-based superalloy, or combinations thereof. The superalloy may include, but not be limited to, a material selected from the group consisting of Hastelloy, Inconel alloys, Waspaloy, Rene alloys, such as GTD111, GTD222, GTD444, GTD262, Mar M247, IN100, IN 738, René 80, IN 939, René N2, René N4, René N5, René N6, René 65, René 77 (Udimet 700), René 80, René 88DT, René 104, René 108, René 125, René 142, René 195, René N500, René N515, IN 706, Nimonic 263, CM247, MarM247, CMSX-4, MGA1400, MGA2400, INCONEL 700, INCONEL 738, INCONEL 792, DS Siemet, CMSX10, PWA1480, PWA1483, PWA1484, TMS-75, TMS-82, Mar-M-200, UDIMET 500, ASTROLOY, and combinations thereof.
Embodiments of the present disclosure, for example, provide narrow gap processing that removes contaminants and oxidation materials from the surfaces of and within deep gaps to provide enhanced quality processing and gap repairs. The processes hereof are particularly well suited for optimizing the processing and sealing of gaps in components, for example, in service run parts having gaps such as are found on the leading edge of an airfoil of a turbine nozzle. The process includes removal of surface contaminants and/or an oxidation layer inside a gap, particularly within deep gaps, using a water jet that delivers a stream of pressurized water with or without one or more abrasive substances. A gap or portion thereof may be cleaned according to the invention in a single pass or in multiple passes, whereby one or more portions or segments of the gap may be processed in a single pass, the full length may be processed in a single pass, and at least a portion may be processed in two or more passes. In some embodiments, a gap may be processed along all or a portion of its length, wherein all or only some portions are cleaned with a jet that includes an abrasive, and wherein in some embodiments, a length of a gap is initially processed with at least one abrasive in a first pass, then without an abrasive in a subsequent pass.
With reference to
With reference to
The process includes capturing a digital image 101 of the gap 203 for processing using software that establishes and guides the water jet cleaning path. The image may be captured by any suitable means that permits processing as required to establish the cleaning path. The process further includes measuring a length of the gap and inner and outer gap dimensions at one or more points along the length of the gap 203 to determine its dimensions (step 102). In certain embodiments, the measuring may further include measuring techniques, such as, but not limited to, utilizing a white light 3D measurement system, a blue light 3D measurement system, and a laser based measuring system, or combinations thereof. The jet cleaning edge can be curved or straight, based on the surface morphology inside and outside the gap. In some embodiments, a partial or through-wall cleaning path can be created according to the extent of penetration of the gap into the part within the depth of the gap.
Referring now to
Thus, in some embodiments the cleaned gap width 302 may be equal to one or both the ID and the OD, or it may be narrower than both the ID and the OD or may be greater than both the ID and OD. It will be appreciated that in some embodiments, the processing disclosed herein will yield a processed gap such that the cleaning path edges 302 may be essentially coextensive with the gap edges 205, thus creating a cleaned gap width 304 that is essential the same as the original gap 203, accomplished in some examples by using an angled cleaning path along at least a portion of the gap so as to closely match the original OD and ID of the gap. And in some embodiments, the gap processing will yield a gap wherein the ID and OD are essentially equal, accomplished in some embodiments using a cutting jet (highly pressurized).
In accordance with various embodiments, the kerf, or width, of the water jet is in the range of about 0.040 inches to about 0.050 inches, and can be as narrow as about 0.020 inches. Non-abrasive cuts are normally 0.007 inches to about 0.013 inches, but can be as small as 0.003 inches, which is approximately the width of a human hair. Water jets are capable of attaining accuracies to about 0.005 inches with repeatability to about 0.001 inches. Thus, gap widths that can be advantageously processed in a service-run part, such as for example a turbine nozzle, are typically less than 0.040 inches, though larger gaps may be beneficially processed by the processes. Thus, gaps having widths in the range from about 0.001 inches to about 0.050 inches may be cleaned according to the instant processes. Thus, in various embodiments, the gap width may be from about 0.005, 0.010, 0.020, 0.030, 0.040, 0.050, 0.060, and 0.070 to about 0.080 including increments thereof and intervals therein. After processing, a gap may be further enlarged to enable adequate cleaning and removal of surface oxidation contaminants since the morphologies of a gap's inside and outside wall surface are often not in the same plane.
A water jet tool may be selected from any of a variety known in the art. The water jet used according to the disclosure may be adjusted with respect to pressure in the range from about 5 to 40,000 psi or higher. It will be appreciated that the pressure may be varied along all or a portion of a gap in order to control the cleaning of the edges and penetration within the depth of a gap. Thus, lower pressure water jets allow removal of superficial material from gap edges, while higher pressure water jets enable penetration into deep gaps while not cutting the part, and the greatest pressure water jets enable cutting and removal of part base material. It will be appreciated that the pressure of the water jet may be selectively varied along a gap, and together with the angle of the jet, its distance from the part, and the distance of the cleaning edge from the gap edge will enable precise control over processing into the depth of a gap and the cleaned gap edge created thereby.
Thus, in various embodiments, the water jet pressure may be from about 5 psi and up to about 40,000 psi, and in some embodiments, the pressure may be at or about 20,000 or less to effect cleaning without cutting, wherein the pressure may be at or about 20,000 psi, or about 15,000 psi, or about 10,000 psi, or about 5,000 psi, or about 1,000 psi, or about 100 psi, or about 10 psi or less to effect cleaning without cutting of a work piece, particularly a metal or alloy. And in some embodiments the pressure may be at least about 20,000 psi, or about 25,000 psi, or about 30,000 psi, or about 35,000 psi, or about 40,000 psi or more to effect cutting of a work piece, particularly a metal or alloy.
In addition to controlling the water jet pressure, the position of the water jet head relative to the work piece may be varied in a range from about 0.040 inches to about 0.060 inches. Thus, the water jet head may be positioned from about 0.040, 0.045, 0.050, and 0.055 to about 0.060 inches above the work piece, and this position may be maintained constant or may be varied along a cleaning path. Referring again to
In accordance with various embodiments, a gap may be processed along its entire length or along any portion of its length. And a gap may be processed by iterative steps that include processing of one or more segments or portions of the gap, wherein any one or more of the steps of imaging, measuring and selecting one or more of the cleaning edge and the cleaning angle may be repeated for separate portions of a gap. In some embodiments, only a portion of a gap may be subjected to one or more steps of the process.
In accordance with the various embodiments, the water jet cleaning edge 302 is from about 0.0005 inches to about 0.0200 inches away from the edge of the gap. Thus, in various embodiments, the cleaning edge 302 may be from about 0.0005 to about 0.0200 inches, or from about 0.0005 to about 0.015 inches, or from about 0.0005 to about 0.010 inches, or from about 0.0010 to about 0.0075 inches, or from about 0.0025 to about 0.0050 inches, and up to about 0.0200 inches, including increments and intervals therein.
Also in accordance with the process as shown in
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
