Turbine component surface treatment process

Abstract

Turbine component surface treatment method (100) comprising: Passing (110) a UV-curable masking agent (31) from a first surface (12) through one or more fluid flow channels (20) to an opposite outer surface (11) of a turbine component (10), wherein at least a portion of the UV-curable masking agent (31) exits the one or more fluid flow channels (20) at the opposite outer surface (11) of the turbine component (10); Applying (120) a UV light (41) to the opposing outer surface (11) of the turbine component (10) at the same time as the UV-curable masking agent (31) is directed from the first surface (12) through the one or more fluid flow channels (20), wherein the application (120) of the UV light (41) cures at least a portion of the UV-curable masking agent (31) exiting the one or more fluid flow channels (20) at the opposing outer surface (11), and wherein the application (120) of the UV light (41) cures at least the exited portion of the UV-curable masking agent (31) into one or more cured stalactites (32) projecting from the opposing outer surface (11); Removing (130) the one or more hardened stalactites (32) from the opposite outer surface (11); after removing (130) the one or more hardened stalactites (32), treating (140) the opposite outer surface (11) with a treatment material (51), wherein a remaining portion of the UV-curable masking agent (31) hardened by the UV light (41) prevents the treatment material from entering the one or more fluid flow channels (20); and Heating (150) the turbine component (10) to thereby remove the UV-curable masking agent (31) after treatment (140) of the opposite outer surface (11).

Description

BACKGROUND OF THE INVENTIONThe subject matter disclosed herein relates to turbine components, and more particularly to methods for treating turbine component surfaces having one or more fluid flow channels.In gas turbines such as aircraft engines, air is drawn into the forward portion of the engine, compressed by a rotating compressor mounted on a shaft, and mixed with fuel. The mixture is burned and the hot exhaust gases are passed through a turbine mounted on a shaft. The gas flow drives the turbine in rotation, which drives the shaft in rotation and drives the compressor and impeller. The hot exhaust gases discharge from the aft portion of the turbine propelling it and the aircraft.During operation of gas turbines, the temperatures of the combustion gases may exceed 3,0000° F. (1649° C.), which is considerably above the melting points of the engine's metal components that contact these gases. Operation of these engines at gas temperatures that exceed the melting points of the metal components may depend, in part, on supplying cooling air to the outer surfaces of the metal components by different methods. The metal components of these engines, which are specifically exposed to high temperatures and thus require special attention to cooling, are those metal components which form burners and parts located after the combustor assembly.Metal temperatures may be maintained below melting point levels through the use of fluid flow passages (also known as cooling holes) incorporated in some engine components. In some cases, one or more coatings, such as thermal barrier coatings (TBCs), may also be applied to the component by a hot spray process. However, coating methods such as the hot spray method and other cleaning methods (e.g., sandblasting, shot peening, water jetting) can result in excessive spraying that partially or fully seals the cooling holes of components.As a result, current coating and cleaning methods may call for a method comprising a plurality of steps: applying a partial coating (e.g., a thermal barrier coating), allowing the component and the coating to cool sufficiently to a temperature at which the component can be readily handled, removing the component from an application device on which hot spraying is performed, and removing any masking, followed by a step of separately removing the appropriately cooled, solidified coating from the fluid flow channels by a water jet method or other cleaning methods. To prevent the fluid flow channels from becoming clogged beyond a level at which they can still be satisfactorily cleaned, only a fraction of the desired coating thickness can be applied prior to cleaning. As a result, the entire process may need to be repeated multiple times until the desired coating thickness is achieved. As a result, this process can have low productivity, cycle time and cost increases of five to ten times over applying the same coating to a comparable unpipped component. Even if no coatings are applied, the pressure cleaning process used to clean the respective surfaces of products can similarly flood and clog or interfere with the fluid flow channels of the product.In the method according to DE 603 10 168 T2, a covering material is introduced into a cooling bore through the workpiece and the coating material and thickened before removing a coating material from the surface of a workpiece. The coating material is then removed.U.S. Pat. No. 6,335,078 B2 discloses a resin in a passage of a substrate, wherein the resin forms a protrusion over the surface of the substrate. The resin can cure, for example, under the action of heat.In the method according to DE 699 11 948 T2, the outer surface of a component is coated with a masking material, wherein the masking material is prevented from penetrating into the cooling opening by pressing a fluid, such as air or water, through a cooling opening. The cooling opening and the channel are then filled with stuffing material by the masking material. Once the stuffing material has cured, the masking material is removed. The surface of the component is then coated.Thus, those skilled in the art would appreciate alternative turbine component surface treatment methods.SUMMARY OF THE INVENTIONAccording to the invention, a turbine component surface treatment method is disclosed. The turbine component surface treatment method includes passing a UV curable masking agent from a first surface through one or more fluid flow channels to an opposing outer surface of a turbine component, wherein at least a portion of the UV curable masking agent exits the one or more fluid flow channels at the opposing outer surface of the turbine component, applying a UV light to the opposing outer surface of the turbine component at the same time as the UV curable masking agent is passed from the first surface through the one or more fluid flow channels, wherein applying the UV light cures at least a portion of the UV curable masking agent exiting the one or more fluid flow channels, and wherein applying the UV light cures at least the leaked portion of the UV curable masking agent to one or more cured crystallites protruding from the outer surface, removing the one or more cured crystallites from the opposing outer surface, after removing the one or more cured crystallites, treating the opposing outer surface with a treatment material, wherein a remaining portion of the UV curable masking agent cured by the UV light prevents the treatment material from entering the one or more fluid flow channels, and heating the turbine component to thereby remove the UV curable masking agent after treating the opposing outer surface.In any embodiment of the method, it may be advantageous that the UV curable masking agent comprises an acrylated urethane epoxy.In any embodiment of the method, it may be advantageous that the treating of the outer surface includes coating the outer surface, wherein the treatment material includes a coating material.In any embodiment of the method, it may be advantageous that the UV curable masking agent includes a brazing cap material.In any embodiment of the method, it may be advantageous that the passage of the UV-curable masking agent through the one or more fluid flow channels is achieved at least partially by means of a compressed gas.In any embodiment of the method, it may be advantageous that the treating of the outer surface includes cleaning the outer surface, wherein the treatment material includes a cleaning material.These and additional features disclosed by the embodiments discussed herein will become more fully understood upon reading the following detailed description in conjunction with the drawings.BRIEF DESCRIPTION OF THE DRAWINGSThe embodiments submitted with reference to the figures are illustrative and exemplary and are not intended to limit the invention as defined by the claims. The following detailed description of the illustrative embodiments will be understood after reading in conjunction with the accompanying drawings, in which like elements are denoted by like reference numerals: FIG. 1 illustrates a turbine component surface treatment method according to one or more embodiments shown or described herein; FIG. 2 shows a perspective view of an exemplary turbine component having multiple fluid flow passages, in accordance with one or more embodiments shown or described herein; FIG. 3 is a schematic illustration of a portion of a turbine component surface treatment system not claimed as such, including a UV curable masking agent application device applying a UV curable masking agent, in accordance with one or more embodiments shown or described herein; FIG. 4 schematically illustrates a portion of a turbine component surface treatment system, not claimed as such, having a UV light source applying a UV light, according to one or more embodiments shown or described herein; FIG. 5 schematically illustrates a portion of a turbine component surface treatment system, not claimed as such, having a scraper that removes a portion of the UV curable masking agent cured by the UV light, in accordance with one or more embodiments shown or described herein; and FIG. 6 schematically illustrates a portion of a turbine component surface treatment system, not claimed as such, having a surface treatment device applying a treatment material, in accordance with one or more embodiments shown or described herein.DETAILED DESCRIPTION OF THE INVENTIONOne or more specific embodiments of the present invention will be described below.When elements of various embodiments of the present invention are introduced, the articles "a", "an", "the", and "the" are intended to mean that one or more of the elements are present. The terms "comprise", "include" and "have" are intended to be inclusive and mean that additional elements may be present that are different from the listed elements.Referring to FIG. 1, a turbine component surface treatment method 100 is illustrated. With continued reference to FIGS. 2-6, the turbine component surface treatment method 100 may be utilized to treat (e.g., coat or clean) an outer surface 11 of a turbine component 10, e.g., using a turbine component surface treatment system 90 not claimed as such.The turbine component 10 may include any turbine component 10 having one or more fluid flow passages 20 (also known as cooling holes, cooling passages, fluid passages, or the like). In particular, the turbine component 10 may include one or more fluid flow passages 20 fluidly connected to an outer surface 11 such that a fluid (e.g., cooling air, such as compressor discharge air) may flow through the turbine component 10 via the one or more fluid flow passages 20, exit the outer surface 11, and may possibly assist in cooling one or more locations of the turbine component 10. As will be appreciated herein, the outer surface 11 may include any surface of the turbine component 10 that may need treatment such as coating, cleaning, or the like. The coating can include, for example, at least partial application of a coating material to an outer surface 11, for example by means of a hot spray gun or the like. Cleaning may include, for example, pulling, washing, bathing, submergence, and / or otherwise removing material from the exterior surface 11, for example, by sandblasting, shot peening, water jetting, or the like. While specific examples have been listed herein, it should be understood that, additionally or alternatively, any other treatment step that uses a treatment material 51 that contacts the exterior surface 11 may be performed. The fluid flow channel 20 begins at an opposing outer surface 12 that, as illustrated, allows fluid communication to the outer surface 11 via the one or more fluid flow channels 20.The turbine component 10 may include a number of different turbine components 10. For example, in some embodiments, turbine component 10 may include a combustor cap effusion plate, for example a cap effusion plate for the combustor section, as illustrated in FIG. 2. As should be appreciated herein, such embodiments may facilitate the flow of the UV curable masking agent 31 through a plurality of fluid flow channels 20 in the effusion plate. In other embodiments, the turbine component 10 may include a blade or vane, a shroud, a nozzle, a vane, a transition piece, a combustor, a combustor, or any other turbine component 10 having one or more fluid flow passages 20. In some embodiments, the turbine component 10 may generally include a hot gas path component or a combustor component.The turbine component surface treatment method 100 generally includes the combined steps of passing a UV curable masking agent 31 through one or more fluid flow channels 20 in step 110 and applying a UV light 41 to the outer surface 11 of the turbine component 10 in step 120.The UV curable masking agent 31 applied in step 110 may be based on any material that can be cured when exposed to UV light 41 while having a viscosity that is uncured sufficient to allow it to pass through the one or more fluid channels 20 and exit an outlet opening 21 in the outer surface 11. For example, in some embodiments, the UV curable masking agent 31 may be based on an acrylated urethane epoxy or any other UV curable epoxy. In some embodiments, the UV curable masking agent 31 may include one or more additional ingredients to facilitate the treatment process. For example, if the treatment in step 140 includes brazing (e.g., if the treatment material 51 is based on brazing material), the UV curable masking agent 31 may further be a brazing cap material that may further help prevent subsequent brazing material from flowing into the one or more fluid channels 20. Such a brazing covering material may include, for example, any suitable oxide such as alumina, titania, yttria, magnesia, or the like.The UV curable masking agent 31 may be directed through the one or more fluid flow channels 20 using any suitable methods or devices in step 110. For example, the UV curable masking agent 31 may be directed through the one or more fluid flow channels 20 by any suitable force, such as pressurized gas, a physical force, or any suitable other means capable of urging the UV curable masking agent 31 through the one or more fluid flow channels 20. In some embodiments, such as illustrated in FIG. 3, a device 30 for applying UV curable masking agent 31 may be utilized to direct the UV curable masking agent 31 through the one or more fluid flow channels 20. The device 30 for applying UV-curable masking agent 31 may be based on any suitable material application device, for example a roller, spray device, coater, injector or the like, which not only applies the UV-curable material 31 but also directs it through the one or more fluid flow channels 20 using a suitable force (e.g. by compressed gas or the like). For example, the device 30 for applying UV curable masking agent 31 may roll UV curable masking agent 31 out widely on the other surface 12, then apply a force (e.g., through pressurized gases) to direct the applied UV curable masking agent 31 through the one or more fluid flow channels 20 such that it begins to exit the outlet opening(s) 21 at the outer surface 11 of the turbine component 10.The UV light 41 applied in step 120 may be any UV light 41 capable of curing the UV curable masking agent 31 as it exits the one or more fluid flow channels 20 on the outer surface 11 of the turbine component 10. For example, as illustrated in FIG. 4, the UV light 41 may be applied from a UV light source 40. The UV light source 40 may include any suitable bulb, lamp, rod, arc, or the like, or combinations thereof, capable of generating sufficient UV light 41 to cure at least a portion of the UV curable masking agent 31. The UV light 41 can be applied using a single UV light source 40 or multiple UV light sources 40.Additionally, as illustrated in FIG. 1, the UV light 41 is applied in step 120 during the passage of the UV curable masking agent 31 through the one or more fluid flow channels 20. The UV light 41 is applied at step 120 at the same time that the UV curable masking agent 31 passes through and exits the one or more fluid flow channels 20. In these embodiments, the UV curable masking agent 31 is cured as it exits the outlet opening 21. This in turn results in cured UV curable masking agent 31 protruding (e.g., protruding) from turbine component 10, for example, in the form of stalactites 32, as best illustrated in FIG. 4. Such stalactites are more easily scraped away from the outer surface 11 of the turbine component 10 to facilitate subsequent treatment. Such embodiments may also minimize or eliminate the spreading of UV curable masking agent 31 on the outer surface 11 itself to ensure that the entire outer surface 11 may be treated (e.g., coated or cleaned) with only the one or more fluid flow channels 20 masked.The turbine component surface treatment method 100 includes removing at least a portion of the UV curable masking agent 31 cured by the UV light 41 applied in step 130 in step 130. For example, if a portion of the UV curable masking agent 31 forms satellite 32 during curing by the UV light 41, the turbine component surface treatment method 100 includes removing the one or more stalactites 32 in step 130 prior to treating the outer surface 11 of the turbine component 10 in step 140, If a portion of the UV curable masking agent 31 has cured on the outer surface 11 of the turbine component, in some embodiments, this portion may be removed in step 130 to expose the portion of the outer surface 11 for treatment.The removal of at least a portion of the UV curable masking agent 31 cured by the UV light 41 may be performed by any scraper 60, as illustrated in FIG. 5, for example. The scraper 60 may include any blade, edge, or the like capable of breaking away at least a portion of the UV curable masking agent 31 cured by the UV light 41 from the turbine component exterior surface 11. Moreover, an exposed outer surface 11 and the remaining cured UV curable masking agent 31 may have a substantially uninterrupted surface by removing at least a portion of the UV curable masking agent 31 cured by the UV light 41 to facilitate the subsequent treatment process (e.g., coating or cleaning) in step 140.The turbine component surface treatment method 100 further includes, in step 140, treating the outer surface 11 of the turbine component 10 with a treatment material 51, wherein the portion of the UV curable masking agent 31 cured by the UV light 41 substantially prevents the treatment material 51 from entering the one or more fluid flow channels 20 of the turbine component 10.The treatment in step 140 may include any suitable treatment technique that employs a treatment material 51 on the outer surface 11 of the turbine component 10, such as coating, cleaning, or the like. The coating can include, for example, at least a partial application of a coating material, e.g. by means of a hot spray gun or the like, to the outer surface 11. In some embodiments, where the treatment material 51 includes a coating material, for example, any suitable composition of a thermal barrier coating material. As used herein, the thermal barrier coating material may include, in whole or in part, a bond coat of MCrAlY, where M is preferably Ni, Co, or a combination thereof followed by a layer of yttria stabilized zirconia. In some embodiments, the coating material 51 may include a thermal spray coating, an oxidation protection coating, a metallic coating, a bond coat, a overlay coating, or any other type of coating as may be used for a bond coat, thermal barrier coating, environmental protection coating, or combinations thereof. Likewise, cleaning may include, for example, stripping, washing, bathing, submergence, and / or otherwise removing material from the exterior surface 11 using a cleaning material such as grit for sandblasting, shot peening, water for water jetting, acid for acid pickling, or the like.In some embodiments, the treatment material 51 may be utilized by a surface treatment device 50 (i.e., a device configured to deposit, cast, or otherwise apply the treatment material 51 to the outer surface 11 of the turbine component 10). For example, in embodiments where the treatment material 51 is based on a coating material, the surface treatment device 50 may include any suitable coating device including, but not limited to, thermal spraying, air plasma spraying (APS), high speed oxygen fuel (HVOF) thermal spraying, high speed air spraying (HVAF), vacuum plasma spraying (VPS), electron beam physical vapor deposition (EBPVD), chemical vapor deposition (CVD), ion plasma spraying (IPD), powder or rod flame spraying, cold spraying, sol-gel, electrophoretic deposition, film casting, polymer-derived ceramic coating, slurry coating, dipping methods, vacuum coating methods, cast coating methods, spread coating, roll coating, agglomeration, and sintering, followed by spray drying, or combinations thereof.As illustrated in FIG. 6, the UV curable masking agent 31 cured by the UV light 41 may be disposed in and may protrude from the one or more fluid flow channels 20 substantially prevent the treatment material 51 from entering the one or more fluid flow channels 20. The outer surface 11 of the turbine component 10 may thus be treated (e.g., coated or cleaned) while little or no treatment material 51 (e.g., coating material or cleaning material) enters the one or more fluid flow channels 20. Accordingly, the entire treatment method may thereby require less post treatment effort for the (repeated) clearing of one or more fluid flow channels 20 of treatment material 51 in order to save human labour and to shorten the process time.Further, in step 150, the turbine component surface treatment method 100 includes heating the turbine component 10 to remove the UV curable masking agent 31 after the treatment of the exterior surface performed in step 140. The heating in step 150 may include applying any amount of heat sufficient to remove the remaining UV curable masking agent 31 remaining in the one or more fluid flow channels 20, such as by being burned or at least melted to drain. In some embodiments, the heating in step 150 may include the same action as curing the treatment material 51 applied to the exterior surface 11 (e.g., when a coating material is cured). In further embodiments, the heating in step 150 to remove the UV curable masking agent 31 from the one or more fluid flow channels 20 may comprise a separate step. The heating in step 150 may further include heating to any suitable temperature for any suitable time in any suitable atmosphere. For example, in some embodiments, heating in step 150 may include heating to a temperature of at least 1,200°F (649°C) to aid in the combustion of the UV curable masking agent 31.In some embodiments, the turbine component surface treatment method 100 may be performed using a turbine component surface treatment system 90 not claimed as such, as illustrated in FIGS. 3-6. The turbine component surface treatment system 90 may generally include one or more elements discussed herein with respect to performing the turbine component surface treatment method 100.For example, the turbine component surface treatment system 90 may generally include a UV curable masking agent application device 30 configured to direct the UV curable masking agent 31 through one or more fluid flow channels 20 of the turbine component 10 illustrated in FIG. 3.As discussed above, the apparatus 30 for applying UV curable masking agent 31 may be configured such that at least a portion of the UV curable masking agent 31 exits the one or more fluid flow channels 20 (e.g., an outlet opening 21) on an outer surface 11 of the turbine component 10.The turbine component surface treatment system 90 may further include a UV light source 40 configured to apply a UV light 41 to the outer surface 11 of the turbine component 10, as illustrated in FIG. 4. As discussed above, the UV light source 40 may be configured such that the UV light 41 cures at least a portion of the UV curable masking agent 31 exiting the one or more fluid flow channels 20.Additionally, as illustrated in FIG. 6, the turbine component surface treatment system 90 may include a surface treatment device 50. The surface treatment device 50 may be configured to treat the outer surface 11, wherein the portion of the UV curable masking agent 31 cured by the UV light 41, e.g., stalactites 32, substantially prevents a treatment material 51 from entering the one or more fluid flow channels 20. For example, the surface treatment device 50 may include a coater (e.g., a hot spray gun or the like), a cleaner (e.g., a sandblasting device or the like), or any other device suitable for treating the outer surface 11 of the turbine component 10 with a treatment material 51.The turbine component surface treatment system 90 may optionally include any additional elements to facilitate treatment of the outer surface 11 of the turbine component 10. For example, in some embodiments, the turbine component surface treatment system 90 may include a scraper 60 as illustrated in FIG. 5. As discussed above, the scraper 60 may be used prior to treating the exterior surface 11 to, for example, completely or at least partially remove the portion of the UV curable masking agent 31 cured by the UV light 41 (e.g., stalactites 32) before the surface treatment device 50 treats the exterior surface 11 of the turbine component 10. In still further embodiments, the turbine component surface treatment system 90 may include a heater configured to heat the turbine component 10 to remove the UV curable masking agent 31 after the surface treatment device 50 treats the exterior surface 11 of the turbine component 10.At this point, it should be appreciated that the turbine component surface treatment methods of the present invention may be utilized to mask fluid flow channels in turbine components by passing a UV curable masking agent through the fluid flow channels and applying a UV light to an exterior surface. As the UV curable masking agent exits the fluid flow channels on the outer surface, the UV light may cure at least the portion of the UV curable masking agent. The protruding cured portion of the UV curable masking agent (e.g., stalactite) may thereby be removed such that the remaining outer surface may be treated, e.g., by coating or cleaning, without treatment material entering the one or more fluid flow channels.A turbine component surface treatment method includes passing a UV curable masking agent through one or more fluid flow channels, at least a portion of the UV curable masking agent exiting the one or more fluid flow channels at an outer surface of the turbine component, applying a UV light to the outer surface of the turbine component, the UV light curing at least a portion of the UV curable masking agent exiting the one or more fluid flow channels, and treating the outer surface with a treatment material, the remaining portion of the UV curable masking agent cured by the UV light substantially preventing the treatment material from entering the one or more fluid flow channels.LIST OF REFERENCE CHARACTERS10 Turbine component 11 Outer surface 12 Other surface 20 Fluid flow channel 21 Outlet opening 30 Ultraviolet curable masking agent applying device 31 Ultraviolet curable masking agent 32 Satellite 40 Ultraviolet light source 41 Ultraviolet light 50 Surface treatment device 51 Treatment material 60 Scraper 90 Turbine component surface treatment system 100 Turbine component surface treatment method 110 Step (masking agent) 120 Step (ultraviolet light) 130 Step (removal) 140 Step (treatment) 150 Step (heating)

Claims

A turbine component surface treatment method (100) comprising: passing (110) a UV curable masking agent (31) from a first surface (12) through one or more fluid flow channels (20) to an opposing outer surface (11) of a turbine component (10), wherein at least a portion of the UV curable masking agent (31) exits the one or more fluid flow channels (20) at the opposing outer surface (11) of the turbine component (10); applying (120) a UV light (41) to the opposing outer surface (11) of the turbine component (10) at the same time as the UV curable masking agent (31) is directed from the first surface (12) through the one or more fluid flow channels (20), wherein applying (120) the UV light (41) cures at least a portion of the UV curable masking agent (31) that exits the one or more fluid flow channels (20) on the opposing outer surface (11), and wherein applying (120) the UV light (41) cures at least the exiting portion of the UV curable masking agent (31) to one or more cured stalactites (32) that protrude from the opposing outer surface (11); Removing (130) the one or more cured stalactites (32) from the opposing outer surface (11); after removing (130) the one or more cured stalactites (32), treating (140) the opposing outer surface (11) with a treatment material (51), wherein a remaining portion of the UV curable masking agent (31) cured by the UV light (41) prevents the treatment material from entering the one or more fluid flow channels (20); and heating (150) the turbine component (10) to thereby remove the UV curable masking agent (31) after the treatment (140) of the opposing outer surface (11).The turbine component surface treatment method (100) of claim 1, wherein the UV curable masking agent (31) exits a plurality of fluid flow channels (20) on the opposing outer surface (11) of the turbine component (10).The turbine component surface treatment method (100) of any preceding claim, wherein the UV curable masking agent (31) comprises an acrylated urethane epoxy.The turbine component surface treatment method (100) of any preceding claim, wherein treating (140) the opposing outer surface (11) comprises coating the outer surface (11), and wherein the treatment material comprises a coating material.The turbine component surface treatment method (100) of any preceding claim, wherein the UV curable masking agent (31) includes a brazing cover material.The turbine component surface treatment method (100) of any preceding claim, wherein treating (140) the opposing outer surface (11) includes cleaning the outer surface (11), and wherein the treatment material includes a cleaning material.The turbine component surface treatment method (100) of any preceding claim, wherein passing (110) the UV curable masking agent (31) through the one or more fluid flow channels (20) is achieved at least partially by means of a pressurized gas.

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