GB2270527A - Coating a face of a component using apertured mask of same size as the face; turbine tip blades - Google Patents

Coating a face of a component using apertured mask of same size as the face; turbine tip blades Download PDF

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Publication number
GB2270527A
GB2270527A GB9219265A GB9219265A GB2270527A GB 2270527 A GB2270527 A GB 2270527A GB 9219265 A GB9219265 A GB 9219265A GB 9219265 A GB9219265 A GB 9219265A GB 2270527 A GB2270527 A GB 2270527A
Authority
GB
United Kingdom
Prior art keywords
face
component
coating
aperture
sheet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9219265A
Other versions
GB9219265D0 (en
Inventor
Keith Charles Moloney
Peter John Gillbanks
Derek John Foster
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rolls Royce PLC
Original Assignee
Rolls Royce PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rolls Royce PLC filed Critical Rolls Royce PLC
Priority to GB9219265A priority Critical patent/GB2270527A/en
Publication of GB9219265D0 publication Critical patent/GB9219265D0/en
Publication of GB2270527A publication Critical patent/GB2270527A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/12—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using a rubstrip, e.g. erodible. deformable or resiliently-biased part
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B12/00—Arrangements for controlling delivery; Arrangements for controlling the spray area
    • B05B12/16—Arrangements for controlling delivery; Arrangements for controlling the spray area for controlling the spray area
    • B05B12/20—Masking elements, i.e. elements defining uncoated areas on an object to be coated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/12—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding
    • B23K20/1215—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding for other purposes than joining, e.g. built-up welding
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Coating By Spraying Or Casting (AREA)

Abstract

A protective coating is applied to an end face 22 of variable width of a component such as an aerofoil section gas turbine rotor blade by preparing an apertured mask 28 in which the aperture 30 is the same size and shape as the end face of the blade, placing the mask over the end face of the blade so that the end face is coplanar with the mask and the periphery of the face is substantially coterminous with the periphery of the aperature, coating the exposed face and those areas of the mask immediately surrounding the aperture and removing the mask on cessation of the coating operation (see Fig 5). The masking material may be metal which is removed by electro-discharge machining. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO COATING COMPONENTS This invention concerns improvements in or relating to coating components, and in particular relates to an improved method of applying a coating to a tip of a gas turbine rotor blade.
In a gas turbine engine, particularly those used in aircraft engine, it is desirable in the interests of engine efficiency that the tips of the rotor blades run as close as possible to the engine casing, so as to minimise gas losses through the clearance between the rotor blade tips and the casing.
Rotor blades undergo radial expansion when the engine is being run. This radial expansion has two components, namely thermal expansion and centrifugal expansion, which do not occur simultaneously or at the same rate during the engine start-up and operating cycles.
Various complex mechanical arrangements are available to alleviate these expansion effects and to ensure that unacceptably large radial clearances and "rubbing" of the blade tip against the casing are minimised at all times.
Whereas the above mechanical arrangements are usually effective most of the time, there are nevertheless times during the engine operating cycle where rubbing of the blade tip against the casing cannot be avoided.
Clearly, rotor blade tips will wear in service and the efficiency of the engine will gradually deteriorate over the life of the engine as increasing quantities of gas leak between the blade tips and the engine casing.
Hitherto, this problem has been addressed by coating the blade tip by, for example, plasma spraying or plating.
However, coatings applied by these methods tend to spall off the blade during service.
We have found that a good metallurgical bond between a coating and a substrate can generally be applied by the technique of friction surfacing, and that hard facing, fire resistant, abrasive, or impregnated materials can all be applied by this technique.
However, when friction surfacing is used to apply a coating to an end face of an aerofoil section blade we have found that the coating does not adhere to the narrower portion of the end face. This phenomenon of the prior art is illustrated in Figure 1 of the accompanying drawings. Figure 1 is a diagrammatic non-scale perspective view from above of an end portion of an aerofoil section rotor blade 10 showing an end face 12 of the blade having a wide portion 14 and a narrow portion 16 corresponding respectively to the thick and thin cross sections of the aerofoil design of the blade. For clarity, the vertical dimension of the drawing has been exaggerated. The end face 12 has been coated any friction surfacing to provide an abrasion resistant coating 18.It will be seen that the coating 18 adheres to the end face 12 of the blade only at the wide section 14, and the narrow section 16 remains uncoated.
It is an object of the present invention to provide a method of applying a protective coating by means of a friction surfacing technique to a face of a component, the face being of variable width, so that the entirety of the face becomes coated with the protective coating.
According to a first aspect of the present invention there is provided a method of applying a protective coating to a face of a component, the face being of variable width, the method comprising the steps of, providing an aperture in a sheet of masking material, the aperture being of substantially the same shape and dimensions as said face of the component, placing the sheet of masking material over said face of the component so that the face is substantially coplanar with the outer surface of the sheet of masking material and the periphery of the face is substantially coterminous with the periphery of the aperture, applying by means of a friction surfacing technique a coating of protective material to said face of the component exposed through the aperture and to a region of the sheet of masking material immediately surrounding the aperture, and removing the sheet of material from the component on cessation of the friction surfacing step.
According to a second aspect of the present invention there is provided a component having a face coated with a protective coating by the method of the first aspect of the invention.
The invention will now be described by way of example only with reference to Figures 2-7 of the accompanying diagrammatic non-scale drawings, in which all the view are perspective views from above and the vertical scale has been exaggerated for clarity, as follows: Figure 1 shows an end portion of an aerofoil section rotor blade having an end face partly coated by a friction surfacing process according to the prior art.
Figure 2 shows an end portion of an aerofoil section rotor blade prior to being coated with a protective coating by the method of the invention.
Figure 3 shows an apertured mask to be used in association with the blade of Figure 2.
Figure 4 shows the apertured mask of Figure 3 placed on an end of the blade of Figure 2, Figure 5 shows the arrangement of Figure 4 in association with a friction surfacing apparatus and at the commencement of a friction surfacing operation.
Figure 6 shows the arrangement of Figure 4 after the friction surfacing operation of Figure 5 has been completed, and Figure 7 shows the blade of Figure 2 coated with a protective coating as applied by the friction surfacing apparatus shown in Figure 5.
Referring to Figure 2 there is shown an aerofoil section rotor blade 20 for a gas turbine engine. One end of the blade 20 has an end face 22 at right angles to the longitudinal axis of the blade. This end face 22 has a wide portion 24 and a relatively narrow portion 26 in accordance with the aerofoil design of the blade. The other end (not shown) of the blade 20 will, in operation, be attached to a gas turbine rotor disk by one of a number of methods well known in the art, a description of which is not necessary to the exposition of the present invention.
In Figure 3 there is shown a sheet of masking material comprising an apertured metal mask 28 provided with an aperture 30 which is the same size and shape as the end face 22 of the rotor blade 20. The mask 28 is then placed over the end face 22 of the blade 20 so that the end of the blade enters the aperture 30 and the end face is coplanar with the upper surface of the mask, as illustrated in Figure 4. It will be appreciated that if the aperture 30 is the same size and shape as the end face 22 of the blade 20, the clearance between the blade and the wall of the aperture will be a minimum, the periphery of the end face being substantially coterminous with the periphery of the aperture.
In Figure 5 there is shown the start of a friction surfacing process. There is provided, located above the masked blade of Figure 4, a friction surfacing machine indicated generally by numeral 32. A friction surfacing rod 34 projects out of the base of the friction surfacing machine 32 and contacts the mask 28 and blade end face 22. The friction surfacing is carried out by moving the friction surfacing rod 34 in the directions of arrows 36 and 38 by means of the machine 34 so as to deposit evenly a layer of protective material from the rod not only on the end face 22 but on the surrounding regions of the mask 28. It will be understood that the nature of the protective material is not particular to the present invention; the protective material will be chosen to suit specific applications.
The result of the deposition is shown in Figure 6 where a layer 40 of protective material covers the end face 22 and the surrounding regions of the mask 28.
Finally, the mask 28 is removed, leaving the deposited layer 40 of protective material covering to an even thickness, and strongly adhering to, the whole area of the end face 22 of the blade 20. The removal of the mask 28 is carried out by electro-discharge machining; this ensures that the protective coating does not break away when the nozzle is removed, as it would do were the mask removed by mechanical means.
Although the invention has been described particularly with reference to coating an end portion of an aerofoil section rotor blade it will be appreciated that the method may be applied to coating irregularly shaped surfaces on other components or artefacts. Surface coating techniques other than friction surfacing may also be used.

Claims (9)

1 A method of applying a protective coating to a face of a component, the face being of variable width, the method comprising the steps of, providing an aperture in a sheet of masking material, the aperture being of substantially the same shape and dimensions as said face of the component, placing the sheet of masking material over said face of the component so that component enters the aperture, the face of the component is substantially coplanar with the outer surface of the sheet of masking material and the periphery of the face is substantially coterminous with the periphery of the aperture, applying by means of a surface coating technique a coating of protective material to said face of the component exposed through the aperture and to a region of the sheet of masking material immediately surrounding the aperture, and removing the sheet of masking material from the component on cessation of the coating technique.
2 A method as claimed in claim 1 wherein the surface coating technique is a friction surfacing technique.
3 A method as claimed in claim 1 or 2 wherein the component is a member having an aerofoil cross section and said face is an end face of the member.
4 A method as claimed in claim 3 wherein the member is a gas turbine rotor blade.
5 A method as claimed in any preceding claim wherein the sheet of masking material is metal.
6 A method as claimed in claim 5 wherein the sheet of masking material is removed by electro-discharge machining.
7 A method of applying a protective coating to a face of a component, substantially as hereinbefore described with reference to Figures 2-7 of the accompanying drawings.
8 A component having a face coated with a protective coating by the method as claimed in any preceding claim.
9 A component having a face coated with a protective coating, substantially as hereinbefore described with reference to Figure 7 of the accompanying drawings.
GB9219265A 1992-09-11 1992-09-11 Coating a face of a component using apertured mask of same size as the face; turbine tip blades Withdrawn GB2270527A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9219265A GB2270527A (en) 1992-09-11 1992-09-11 Coating a face of a component using apertured mask of same size as the face; turbine tip blades

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9219265A GB2270527A (en) 1992-09-11 1992-09-11 Coating a face of a component using apertured mask of same size as the face; turbine tip blades

Publications (2)

Publication Number Publication Date
GB9219265D0 GB9219265D0 (en) 1992-10-28
GB2270527A true GB2270527A (en) 1994-03-16

Family

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Family Applications (1)

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GB9219265A Withdrawn GB2270527A (en) 1992-09-11 1992-09-11 Coating a face of a component using apertured mask of same size as the face; turbine tip blades

Country Status (1)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0925845A3 (en) * 1997-12-19 2001-02-07 United Technologies Corporation Shield and method for protecting an airfoil surface
WO2010048931A1 (en) * 2008-10-27 2010-05-06 Mtu Aero Engines Gmbh Apparatus for partial covering of a component zone
WO2014126732A1 (en) 2013-02-12 2014-08-21 United Technologies Corporation Metallic coating fixed stator tip treatment
DE102014218167A1 (en) 2014-09-11 2016-03-17 MTU Aero Engines AG Method of blade tip armor

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0078083A2 (en) * 1981-10-22 1983-05-04 Palomar Systems And Machines, Inc. Process and plate for processing miniature electronic components
GB2127855A (en) * 1982-10-05 1984-04-18 Owen S G Ltd Selective plating
GB2151159A (en) * 1983-11-17 1985-07-17 Murata Manufacturing Co Method of forming external electrodes of chip parts and tool therefor
GB2152854A (en) * 1983-12-27 1985-08-14 Champion Spark Plug Co Coating portions of articles
GB2169923A (en) * 1985-01-22 1986-07-23 Avx Corp Method of applying terminations to ceramic bodies
GB2212818A (en) * 1987-11-28 1989-08-02 Murata Manufacturing Co Electronic component chip holder
GB2222378A (en) * 1988-08-30 1990-03-07 Friction Technology Ltd Forming hard facings on materials

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0078083A2 (en) * 1981-10-22 1983-05-04 Palomar Systems And Machines, Inc. Process and plate for processing miniature electronic components
GB2127855A (en) * 1982-10-05 1984-04-18 Owen S G Ltd Selective plating
GB2151159A (en) * 1983-11-17 1985-07-17 Murata Manufacturing Co Method of forming external electrodes of chip parts and tool therefor
GB2152854A (en) * 1983-12-27 1985-08-14 Champion Spark Plug Co Coating portions of articles
GB2169923A (en) * 1985-01-22 1986-07-23 Avx Corp Method of applying terminations to ceramic bodies
GB2212818A (en) * 1987-11-28 1989-08-02 Murata Manufacturing Co Electronic component chip holder
GB2222378A (en) * 1988-08-30 1990-03-07 Friction Technology Ltd Forming hard facings on materials

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0925845A3 (en) * 1997-12-19 2001-02-07 United Technologies Corporation Shield and method for protecting an airfoil surface
SG80605A1 (en) * 1997-12-19 2001-05-22 United Technologies Corp Sheild and method for protecting an airfoil surface
WO2010048931A1 (en) * 2008-10-27 2010-05-06 Mtu Aero Engines Gmbh Apparatus for partial covering of a component zone
WO2014126732A1 (en) 2013-02-12 2014-08-21 United Technologies Corporation Metallic coating fixed stator tip treatment
EP2929065A4 (en) * 2013-02-12 2016-06-01 United Technologies Corp Metallic coating fixed stator tip treatment
DE102014218167A1 (en) 2014-09-11 2016-03-17 MTU Aero Engines AG Method of blade tip armor
DE102014218167B4 (en) 2014-09-11 2018-09-27 MTU Aero Engines AG Method of blade tip armor

Also Published As

Publication number Publication date
GB9219265D0 (en) 1992-10-28

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)