CA2366325A1 - Method of forming turbine blade root - Google Patents
Method of forming turbine blade root Download PDFInfo
- Publication number
- CA2366325A1 CA2366325A1 CA002366325A CA2366325A CA2366325A1 CA 2366325 A1 CA2366325 A1 CA 2366325A1 CA 002366325 A CA002366325 A CA 002366325A CA 2366325 A CA2366325 A CA 2366325A CA 2366325 A1 CA2366325 A1 CA 2366325A1
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- CA
- Canada
- Prior art keywords
- root
- turbine blade
- subjected
- edm
- tool
- 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.)
- Abandoned
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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
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
-
- 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
- B23H9/10—Working turbine blades or nozzles
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/3601—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
- B23K35/3608—Titania or titanates
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/362—Selection of compositions of fluxes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P13/00—Making metal objects by operations essentially involving machining but not covered by a single other subclass
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
- C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2230/00—Manufacture
- F05D2230/10—Manufacture by removing material
- F05D2230/11—Manufacture by removing material by electrochemical methods
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2230/00—Manufacture
- F05D2230/10—Manufacture by removing material
- F05D2230/12—Manufacture by removing material by spark erosion methods
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/47—Burnishing
- Y10T29/479—Burnishing by shot peening or blasting
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49316—Impeller making
- Y10T29/49336—Blade making
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Inorganic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The present invention relates to a process for forming the root of a turbine blade using the EDM method. EDM
machining of the root is done in a manner that any re-cast layer left behind is less than 1 micron. After EDM
machining the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete.
The root is then subjected to glass beeding to remove any re-cast and insure the surface finish prior to shot peening is consistent and contains no scratch marks or machine marks. The root is then subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
machining of the root is done in a manner that any re-cast layer left behind is less than 1 micron. After EDM
machining the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete.
The root is then subjected to glass beeding to remove any re-cast and insure the surface finish prior to shot peening is consistent and contains no scratch marks or machine marks. The root is then subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
Description
TITLE: METHOD OF FORMING TURBINE BLADE ROOT
FIELD OF THE INVENTION
The present invention relates to a process for making turbine blades for use in power generation, aerospace, the pumping industries and the like. In particular it relates to a process for forming the root of the turbine blade.
BACKGROUND OF THE INVENTION
The turbine blade, for example, in the jet engine, has a very simple purpose, to re-direct and compress air. The turbine blade is attached to a ring. along with a varying number of identical turbine blades. When the turbine blades are all installed to the ring, they form a perfect circle. Several stages of rings are mounted, one behind the other, each with fewer and fewer blades. As the rings are rotated, each blade moves air using the principal of an airfoil and/or bucket. As the air is passed on to the next stage, the area, or volume decreases, thereby compressing the air into a smaller and smaller area. Once the air finally reaches the required volume, it is mixed with~fuel and ignited causing a massive controlled explosion, which is then directed in some cases into w another ring of turbine blades.
The turbine blade has a blade or foil and a root. The root allows the. blade to be affixed to the rotating disk or ring. The root is a critical feature, as the root must be a near perfect fit in order to prevent separation from the disk.
The current methods of manufacturing a root are generally broken down into three categories: grinding, broaching or machining with a form tool. Using one of these methods a root can be produced relatively quickly at an acceptable price. The turbine blade and root are usually made from stainless steel ranging in many different grades. Blades, while less common can also be made .from super alloys and ceramics with high nickel content. It is for this reason that machining.or removing material to form the root is extremely difficult.
When forming a root by grinding, a blank is mounted into a CNC (computer numerical controlled) grinder. The root shape is ground in with a grinding wheel having the opposing shape of the root to be formed.
The broaching process is also quite a simple concept.
Again, a blank is mounted into a broaching machine, where a long flat cutting tool moves perpendicular to the part.
On the flat bar, cutting teeth remove the material, as the bar moves from top to bottom.
Finally, machining with a form tool, also simple to explain is one of the most common practices. A form tool, described as it sounds, is a cutting tool, which has the desired shape of the root ground in. This cutting tool is used in various styles of machining centers, and basically is spun at the required RPM (revolutions per minute) and moved perpendicular into the blank to machine in the root. ' . . ' . .. .,. ._ .
Manufacturing the root with a broach or a form tool w raises two immediate problems. First, in both instances, if the broach or the form tool breaks in the middle of a production run, it is nearly impossible to reproduce or repair the broaching tool or form tool to the identical shape. This will cause mis-match in a production run.
Second, if a form tool or a broach breaks, and deliveries are critical, in almost every circumstance unless a spare tool is on premises, a new tool can take a long period of time to acquire.
When supplying blades to the service industry, many times with only a used broken part as the pattern to manufacture new pieces, reversing engineering a component is many times the only practical method. The root will be mounted into a ring with has lost a varying amount of material, and the new blade has to fit onto that ring.
The practice is common to supply the service industry with a range of sample parts to fit onto the ring, in order to achieve the best fit. If one were to produce these samples with a broaching tool or a form tool, the cost to supply a great number of samples would be high.
This is due in part from the fact that a set of form tools and or broaching tools would require to be ground for each sample.
The methods of machining a root with either broaching, grinding or use of a form tool, all are susceptible to wear. These three processes DO NOT have any means of compensating for tool wear. Subsequently, the manufacturer must rely on frequently changing the tool or redressing the grinding wheel in order to keep the process stable. _ SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for forming the root of a turbine blade that overcomes the problems associated with tool breaks in the middle of a production run.
It is a further object of the present .invention to provide a process for forming the root of a turbine blade that can provide a range of sample parts to fit onto the ring quickly and cost effectively.
It is a further object of the present invention to provide a process for forming the root of a turbine blade that eliminates problems associated with tool wear.
Accordingly the present invention provides a process for forming the root of a turbine blade using the EDM method.
EDM machining of the root is done in a manner that any re-cast layer left behind is less than 1 micron. After EDM machining the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete. The root is then subjected to glass heeding to remove any re-cast and insure the surface finish prior to shot peening is consistent and contains no scratch marks or machine marks. The root is then subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
Further features of the invention will be described or will become apparent in the course of the followingv _ detailed description. r ' - ., DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The electrical discharge machining (EDM) method, according to the present invention, of forming the turbine blade root is very much different from conventional methods based on the fact that all other methods of removing the material effectively rip, tear, or score the material. EDM, as mentioned earlier breaks the material down by conducting a controlled amount of r JVdC-11485/CA - 5 -voltage and current through an electrode in the form of;
in the case of wire EDM a thin wire. Rapidly occurring electrical discharges from the electrode break down the bonding material in the piece being machined. However the EDM method does leave behind on the surface a very small amount of "slag". Vvlhhile manufacture of the blade using EDM is not uncommon, processes proposed to EDM the root have never been commercially acceptable. EDM removal of metal, particularly at higher removal speeds, leaves a re-cast layer on the surface of the. piece being machined.
The re-cast layer is susceptible to cracking and any residual re-cast left on the piece being machined can transfer structural cracks thereby causing component failure.
The speed of removing the material has always been the main driver for EDM manufacturing. The EDM process, of the present invention, to form a root of a turbine blade accomplishes the following objectives:
The root of all the turbine blades manufactured fit uniformly within the mating ring. As noted previously, manufacturing the root with a broach or a form tool raises problems, if the broach or the form tool breaks in the middle of a production run. Using these methods it is nearly impossible to reproduce or repair the broaching tool or form tool to the identical shape. This will cause --mis-match in a production run. Further, if a form tool or a broach breaks, and deliveries are critical, in almost every circumstance unless a spare tool is on premises, a new tool can take a long period of time to acquire. By using the EDM process of the present invention, tool breaks do not create a problem. Replacement electrodes will produce identical pieces and are readily available.
Blades supplied to the service (repair) industry are not generally made to a single specification. Also, when supplying blades to the service industry, many times only mused broken part is provided and reversing engineering a component is the only practical method of manufacture.
The root will be mounted into a ring with has lost a varying amount of material, and the new blade has to fit onto that ring. The practice is to supply the service industry with a range of sample parts to fit onto a ring, in order to achieve the best fit. If one were to produce these samples with a broaching tool or a form tool, the cost would be higher to supply a large number of samples.
This is due in part from the fact that a set of form tools and or broaching tools would require to be ground.
The EDM process of the present invention eliminates the need for a large number of form tools or broaching tools.
The same EDM machine can be programmed to produce different roots to accommodate ring wear.
When machining a root with broaching, grinding or use of a form tool, the tools all are susceptible to wear. These three processes do not have any means of compensating for tool wear. Subsequently, the manufacturer must rely on frequently changing the tool or redressing the grinding wheel in order to keep the process stable. The.EDM'v process of the present invention to form the root of the _ . ._-:._ _ . _. ._ turbine blade is not susceptible to tool wear. The wire:
being used in the process is continuously wound through and disposed.
In known processes of making turbine blade roots after machining, the.root is subjected to: MPI (magnetic particle inspection) and shot peeving. The turbine blade is subjected to MPI to check for depth or presence of .
surface cracks. By shot peeving, the material is effectively bombarded with small media called shot. Each piece of shot striking the material acts as a tiny ball peen hammer, imparting to the surface small indentation or dimples. The effect of this process ultimately produces a compressed surface which resists further surface cracks.
The process of the present invention eliminates any re-cast from the EDM process prior to MPI and shot peeving, In the present invention, EDM machining of the root from a stainless steel workpiece is done in a manner that any re-cast layer left behind is less than 1 micron, After EDM machining, the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete. The root is then subjected to glass heeding to remove any re-cast. By glass heeding the surface prior to shot peeving, the surface finish prior to shot peeving is consistent and contains no scratch marks or machine marks, which are always evident after conventional machining. The root is the subjected to shot peeving to impart to the surface small indentation or dimples. The effect of this step ultimately produces a compressed surface which resists further surface cracks.
The process of the present invention is applicable to forming a turbine blade root in a completely vertical cut (straight cut) or in a similar fashion using multiple cuts at varying angles in order form radial surfaces.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
FIELD OF THE INVENTION
The present invention relates to a process for making turbine blades for use in power generation, aerospace, the pumping industries and the like. In particular it relates to a process for forming the root of the turbine blade.
BACKGROUND OF THE INVENTION
The turbine blade, for example, in the jet engine, has a very simple purpose, to re-direct and compress air. The turbine blade is attached to a ring. along with a varying number of identical turbine blades. When the turbine blades are all installed to the ring, they form a perfect circle. Several stages of rings are mounted, one behind the other, each with fewer and fewer blades. As the rings are rotated, each blade moves air using the principal of an airfoil and/or bucket. As the air is passed on to the next stage, the area, or volume decreases, thereby compressing the air into a smaller and smaller area. Once the air finally reaches the required volume, it is mixed with~fuel and ignited causing a massive controlled explosion, which is then directed in some cases into w another ring of turbine blades.
The turbine blade has a blade or foil and a root. The root allows the. blade to be affixed to the rotating disk or ring. The root is a critical feature, as the root must be a near perfect fit in order to prevent separation from the disk.
The current methods of manufacturing a root are generally broken down into three categories: grinding, broaching or machining with a form tool. Using one of these methods a root can be produced relatively quickly at an acceptable price. The turbine blade and root are usually made from stainless steel ranging in many different grades. Blades, while less common can also be made .from super alloys and ceramics with high nickel content. It is for this reason that machining.or removing material to form the root is extremely difficult.
When forming a root by grinding, a blank is mounted into a CNC (computer numerical controlled) grinder. The root shape is ground in with a grinding wheel having the opposing shape of the root to be formed.
The broaching process is also quite a simple concept.
Again, a blank is mounted into a broaching machine, where a long flat cutting tool moves perpendicular to the part.
On the flat bar, cutting teeth remove the material, as the bar moves from top to bottom.
Finally, machining with a form tool, also simple to explain is one of the most common practices. A form tool, described as it sounds, is a cutting tool, which has the desired shape of the root ground in. This cutting tool is used in various styles of machining centers, and basically is spun at the required RPM (revolutions per minute) and moved perpendicular into the blank to machine in the root. ' . . ' . .. .,. ._ .
Manufacturing the root with a broach or a form tool w raises two immediate problems. First, in both instances, if the broach or the form tool breaks in the middle of a production run, it is nearly impossible to reproduce or repair the broaching tool or form tool to the identical shape. This will cause mis-match in a production run.
Second, if a form tool or a broach breaks, and deliveries are critical, in almost every circumstance unless a spare tool is on premises, a new tool can take a long period of time to acquire.
When supplying blades to the service industry, many times with only a used broken part as the pattern to manufacture new pieces, reversing engineering a component is many times the only practical method. The root will be mounted into a ring with has lost a varying amount of material, and the new blade has to fit onto that ring.
The practice is common to supply the service industry with a range of sample parts to fit onto the ring, in order to achieve the best fit. If one were to produce these samples with a broaching tool or a form tool, the cost to supply a great number of samples would be high.
This is due in part from the fact that a set of form tools and or broaching tools would require to be ground for each sample.
The methods of machining a root with either broaching, grinding or use of a form tool, all are susceptible to wear. These three processes DO NOT have any means of compensating for tool wear. Subsequently, the manufacturer must rely on frequently changing the tool or redressing the grinding wheel in order to keep the process stable. _ SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for forming the root of a turbine blade that overcomes the problems associated with tool breaks in the middle of a production run.
It is a further object of the present .invention to provide a process for forming the root of a turbine blade that can provide a range of sample parts to fit onto the ring quickly and cost effectively.
It is a further object of the present invention to provide a process for forming the root of a turbine blade that eliminates problems associated with tool wear.
Accordingly the present invention provides a process for forming the root of a turbine blade using the EDM method.
EDM machining of the root is done in a manner that any re-cast layer left behind is less than 1 micron. After EDM machining the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete. The root is then subjected to glass heeding to remove any re-cast and insure the surface finish prior to shot peening is consistent and contains no scratch marks or machine marks. The root is then subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
Further features of the invention will be described or will become apparent in the course of the followingv _ detailed description. r ' - ., DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The electrical discharge machining (EDM) method, according to the present invention, of forming the turbine blade root is very much different from conventional methods based on the fact that all other methods of removing the material effectively rip, tear, or score the material. EDM, as mentioned earlier breaks the material down by conducting a controlled amount of r JVdC-11485/CA - 5 -voltage and current through an electrode in the form of;
in the case of wire EDM a thin wire. Rapidly occurring electrical discharges from the electrode break down the bonding material in the piece being machined. However the EDM method does leave behind on the surface a very small amount of "slag". Vvlhhile manufacture of the blade using EDM is not uncommon, processes proposed to EDM the root have never been commercially acceptable. EDM removal of metal, particularly at higher removal speeds, leaves a re-cast layer on the surface of the. piece being machined.
The re-cast layer is susceptible to cracking and any residual re-cast left on the piece being machined can transfer structural cracks thereby causing component failure.
The speed of removing the material has always been the main driver for EDM manufacturing. The EDM process, of the present invention, to form a root of a turbine blade accomplishes the following objectives:
The root of all the turbine blades manufactured fit uniformly within the mating ring. As noted previously, manufacturing the root with a broach or a form tool raises problems, if the broach or the form tool breaks in the middle of a production run. Using these methods it is nearly impossible to reproduce or repair the broaching tool or form tool to the identical shape. This will cause --mis-match in a production run. Further, if a form tool or a broach breaks, and deliveries are critical, in almost every circumstance unless a spare tool is on premises, a new tool can take a long period of time to acquire. By using the EDM process of the present invention, tool breaks do not create a problem. Replacement electrodes will produce identical pieces and are readily available.
Blades supplied to the service (repair) industry are not generally made to a single specification. Also, when supplying blades to the service industry, many times only mused broken part is provided and reversing engineering a component is the only practical method of manufacture.
The root will be mounted into a ring with has lost a varying amount of material, and the new blade has to fit onto that ring. The practice is to supply the service industry with a range of sample parts to fit onto a ring, in order to achieve the best fit. If one were to produce these samples with a broaching tool or a form tool, the cost would be higher to supply a large number of samples.
This is due in part from the fact that a set of form tools and or broaching tools would require to be ground.
The EDM process of the present invention eliminates the need for a large number of form tools or broaching tools.
The same EDM machine can be programmed to produce different roots to accommodate ring wear.
When machining a root with broaching, grinding or use of a form tool, the tools all are susceptible to wear. These three processes do not have any means of compensating for tool wear. Subsequently, the manufacturer must rely on frequently changing the tool or redressing the grinding wheel in order to keep the process stable. The.EDM'v process of the present invention to form the root of the _ . ._-:._ _ . _. ._ turbine blade is not susceptible to tool wear. The wire:
being used in the process is continuously wound through and disposed.
In known processes of making turbine blade roots after machining, the.root is subjected to: MPI (magnetic particle inspection) and shot peeving. The turbine blade is subjected to MPI to check for depth or presence of .
surface cracks. By shot peeving, the material is effectively bombarded with small media called shot. Each piece of shot striking the material acts as a tiny ball peen hammer, imparting to the surface small indentation or dimples. The effect of this process ultimately produces a compressed surface which resists further surface cracks.
The process of the present invention eliminates any re-cast from the EDM process prior to MPI and shot peeving, In the present invention, EDM machining of the root from a stainless steel workpiece is done in a manner that any re-cast layer left behind is less than 1 micron, After EDM machining, the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete. The root is then subjected to glass heeding to remove any re-cast. By glass heeding the surface prior to shot peeving, the surface finish prior to shot peeving is consistent and contains no scratch marks or machine marks, which are always evident after conventional machining. The root is the subjected to shot peeving to impart to the surface small indentation or dimples. The effect of this step ultimately produces a compressed surface which resists further surface cracks.
The process of the present invention is applicable to forming a turbine blade root in a completely vertical cut (straight cut) or in a similar fashion using multiple cuts at varying angles in order form radial surfaces.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims (2)
1. A process for forming the root of a turbine blade comprising the following steps:
(a) EDM machining of the root into the desired shape in a manner that any re-cast layer left behind is less than 1 micron;
(b) After EDM machining, the root is then subjected to glass heeding to remove any re-cast and insure the surface finish is consistent and contains no scratch marks or machine marks; and (c) Then the root is subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
(a) EDM machining of the root into the desired shape in a manner that any re-cast layer left behind is less than 1 micron;
(b) After EDM machining, the root is then subjected to glass heeding to remove any re-cast and insure the surface finish is consistent and contains no scratch marks or machine marks; and (c) Then the root is subjected to shot peening to impart to the surface small indentation or dimples and produce a compressed surface which resists further surface cracks.
2. A process according to claim 1 wherein the additional steps after EDM machining and before glass heeding are provided:
(i) the turbine blade is subjected to MPI to check for depth or presence of surface cracks; and (ii) then a liquid tracer coating applied to the root.
(i) the turbine blade is subjected to MPI to check for depth or presence of surface cracks; and (ii) then a liquid tracer coating applied to the root.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002366325A CA2366325A1 (en) | 2001-12-27 | 2001-12-27 | Method of forming turbine blade root |
| AU2002350355A AU2002350355A1 (en) | 2001-12-27 | 2002-12-27 | Method of forming turbine blade root |
| US10/465,949 US20040064945A1 (en) | 2001-12-27 | 2002-12-27 | Method of forming turbine blade root |
| PCT/CA2002/001983 WO2003059569A2 (en) | 2001-12-27 | 2002-12-27 | Method of forming turbine blade root |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002366325A CA2366325A1 (en) | 2001-12-27 | 2001-12-27 | Method of forming turbine blade root |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2366325A1 true CA2366325A1 (en) | 2003-06-27 |
Family
ID=4170995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002366325A Abandoned CA2366325A1 (en) | 2001-12-27 | 2001-12-27 | Method of forming turbine blade root |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US20040064945A1 (en) |
| AU (1) | AU2002350355A1 (en) |
| CA (1) | CA2366325A1 (en) |
| WO (1) | WO2003059569A2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2149417A2 (en) * | 2008-07-29 | 2010-02-03 | Pratt & Whitney Canada Corp. | Method for wire electro-discharge machining a part |
| US8925201B2 (en) | 2009-06-29 | 2015-01-06 | Pratt & Whitney Canada Corp. | Method and apparatus for providing rotor discs |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101063575B1 (en) * | 2002-09-24 | 2011-09-07 | 미츠비시덴키 가부시키가이샤 | Sliding surface coating method of high temperature member and electrode for high temperature member and discharge surface treatment |
| US9284647B2 (en) * | 2002-09-24 | 2016-03-15 | Mitsubishi Denki Kabushiki Kaisha | Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment |
| TWI272993B (en) * | 2002-10-09 | 2007-02-11 | Ishikawajima Harima Heavy Ind | Method for coating rotary member, rotary member, labyrinth seal structure and method for manufacturing rotary member |
| WO2006087292A1 (en) * | 2005-02-15 | 2006-08-24 | Alstom Technology Ltd | Method for prolonging the fatigue life of a blade footing of a turobmachine blade |
| US20060245923A1 (en) * | 2005-04-27 | 2006-11-02 | General Electric Company | Arcuate nozzle segment and related method of manufacture |
| CN100368128C (en) * | 2006-04-03 | 2008-02-13 | 潘毅 | Method for processing rivet head of moving blade of turbine |
| EP2068872A1 (en) | 2006-09-08 | 2009-06-17 | Braincells, Inc. | Combinations containing a 4-acylaminopyridine derivative |
| GB2442449B (en) * | 2006-10-04 | 2008-06-11 | Rolls Royce Plc | Forming firtree profiles |
| DE102007051838A1 (en) * | 2007-10-30 | 2009-05-07 | Rolls-Royce Deutschland Ltd & Co Kg | Gas turbine blade root comprises two surfaces, which is auxiliary to bearing of gas turbine blade root, which is conjoined in right angle, and transient area of surfaces is formed with tapered and even edge |
| US8959767B2 (en) * | 2012-11-21 | 2015-02-24 | United Technologies Corporation | Method of extending life of rotating parts |
| WO2014197119A2 (en) * | 2013-04-16 | 2014-12-11 | United Technologies Corporation | Rotors with modulus mistuned airfoils |
| US9693077B2 (en) * | 2013-12-13 | 2017-06-27 | Qualcomm Incorporated | Controlling sub prediction unit (sub-PU) motion parameter inheritance (MPI) in three dimensional (3D) HEVC or other 3D coding |
| CN106636589B (en) * | 2016-10-08 | 2018-07-24 | 中国航空工业集团公司北京航空制造工程研究所 | A kind of stress peening method of control hollow blade deformation |
| US20180112542A1 (en) * | 2016-10-24 | 2018-04-26 | Pratt & Whitney Canada Corp. | Gas turbine engine rotor |
| CN112324515B (en) * | 2020-10-29 | 2022-10-18 | 中国航发南方工业有限公司 | Turbine blade reliability improvement method |
| CN117840517B (en) * | 2024-03-07 | 2024-06-07 | 宁波永灵航空科技有限公司 | Machining tool for multi-blade annular thin-wall part of aero-engine and application method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3668913A (en) * | 1970-10-05 | 1972-06-13 | Metal Improvement Co | Apparatus for shot-peening turbine blades |
| DE2231426C3 (en) * | 1972-06-27 | 1974-11-28 | Motoren- Und Turbinen-Union Muenchen Gmbh, 8000 Muenchen | Shroudless, internally cooled axial turbine rotor blade |
| US3847506A (en) * | 1973-11-29 | 1974-11-12 | Avco Corp | Turbomachine rotor |
| US4428213A (en) * | 1981-09-10 | 1984-01-31 | United Technologies Corporation | Duplex peening and smoothing process |
| US4888863A (en) * | 1988-03-21 | 1989-12-26 | Westinghouse Electric Corp. | Method and apparatus for producing turbine blade roots |
| US5055783A (en) * | 1989-09-05 | 1991-10-08 | Westinghouse Electric Corp. | Magnetic field strength indicator for use prior to a magnetic particle inspection procedure |
| DE4203656C2 (en) * | 1992-02-08 | 2000-06-21 | Abb Patent Gmbh | Device for producing axial grooves on rotor disks of a turbine rotor |
-
2001
- 2001-12-27 CA CA002366325A patent/CA2366325A1/en not_active Abandoned
-
2002
- 2002-12-27 AU AU2002350355A patent/AU2002350355A1/en not_active Abandoned
- 2002-12-27 US US10/465,949 patent/US20040064945A1/en not_active Abandoned
- 2002-12-27 WO PCT/CA2002/001983 patent/WO2003059569A2/en not_active Application Discontinuation
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2149417A2 (en) * | 2008-07-29 | 2010-02-03 | Pratt & Whitney Canada Corp. | Method for wire electro-discharge machining a part |
| EP2149417A3 (en) * | 2008-07-29 | 2012-02-29 | Pratt & Whitney Canada Corp. | Method for wire electro-discharge machining a part |
| US10189100B2 (en) | 2008-07-29 | 2019-01-29 | Pratt & Whitney Canada Corp. | Method for wire electro-discharge machining a part |
| US11583947B2 (en) | 2008-07-29 | 2023-02-21 | Pratt & Whitney Canada Corp. | Method for wire electro-discharge machining a part |
| US8925201B2 (en) | 2009-06-29 | 2015-01-06 | Pratt & Whitney Canada Corp. | Method and apparatus for providing rotor discs |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2003059569A3 (en) | 2003-09-25 |
| US20040064945A1 (en) | 2004-04-08 |
| AU2002350355A8 (en) | 2003-07-30 |
| AU2002350355A1 (en) | 2003-07-30 |
| WO2003059569A9 (en) | 2004-02-05 |
| WO2003059569A2 (en) | 2003-07-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |