JP6567394B2 - Method for repairing worn parts of gas turbine parts - Google Patents

Description

The present invention relates to a wear part repairing method for a gas turbine component to repair the worn portion occurring in a gas turbine component.

  In a gas turbine power plant, compressed air and fuel compressed by driving a compressor provided coaxially with a gas turbine are introduced into a combustor liner, and these are combusted in a combustion chamber of the combustor liner. The high-temperature combustion gas generated by this combustion is introduced into a gas turbine composed of a turbine stationary blade and a turbine rotor blade through a transition piece, and expands to rotate the turbine rotor blade. In the gas turbine power generation plant, the kinetic energy generated by the rotational drive is used to generate power by rotationally driving a generator or the like.

  Ni-based, Co-based, or Ni-Fe-based heat-resistant superalloys are used for combustor liners, transition pieces, turbine stationary blades, and turbine rotor blades that are high-temperature parts of gas turbines. Various damages occur with operation. First, since it is in a high-temperature combustion gas atmosphere, material deterioration occurs for each component. Further, when the gas turbine is started, thermal fatigue occurs at the stage of transition from the relatively low temperature environment region to the high temperature environment region and when the gas turbine is stopped, conversely, the fatigue damage accumulates and a crack occurs.

  By the way, the maintenance management of high-temperature parts in the gas turbine is the same model or the same based on the creep or fatigue life determined at the design stage of the equipment and the design life set according to the actual operating conditions and location environment. The gas turbines that take the operation form are classified, the design life is corrected using the results of the preceding machines of each classified group, and the maintenance of the subsequent machines is performed. In recent years, a maintenance management method for efficiently and accurately predicting deterioration and damage diagnosis of high-temperature parts of a gas turbine has been implemented. In any maintenance management method, repairs are repeated every regular inspection as necessary, and after reaching the management life, they are uniformly discarded and replaced with very expensive new ones.

  Moreover, in the repair for every routine inspection of the turbine blade, when wear occurs due to use, the wear part is formed and the wear resistant material is repaired by welding.

Japanese Patent Laid-Open No. 10-293049

  In the conventional overlay repair by welding, although it depends on the value of heat input, cracks are likely to occur after welding, and repair was repeated until the cracks disappeared while removing the cracks once generated. For this reason, there is a problem that the repair cost increases.

An object of the present invention has been made in consideration of the above-described circumstances, and provides a method for repairing a worn portion of a gas turbine component that can suitably repair a worn portion of a gas turbine component without causing a crack. It is in.

A method for repairing a wear site of a gas turbine component according to the present invention is a method for repairing a wear site of a gas turbine component that repairs a wear site generated on an outer surface through which combustion gas flows in the gas turbine component, A molding process for forming a molded part by processing a wear part, a loading process for loading a repair material made of an abrasion-resistant material using a bonding material in the molded part, and the gas turbine component loaded with the repair material And performing a diffusion heat treatment to bond the repair material and the gas turbine component through the bonding material, and the forming step is to process the formed portion into a concavo-convex shape, The repair material is provided with a contact surface that fits and fits into the molded part, and the repair material is a cobalt-based resistant material having a hardness higher than that of the base of the gas turbine component. It is a wear material, and its chemical composition is 0.05 to 0.15% carbon, 19 to 21% chromium, 9.0 to 11.0% nickel, and 14 to 16% tungsten. Manganese is 1.0 to 2.0%, inevitable element is several%, and the balance is cobalt .

  According to the present invention, since the repair material made of the wear-resistant material is diffusion bonded to the wear part of the gas turbine part, the gas is generated without causing a crack that occurs when the wear part is repaired by welding. The worn part of the turbine part can be suitably repaired.

Sectional drawing which shows the gas turbine power plant provided with the turbine rotor blade repaired by 1st Embodiment in the abrasion site | part repair method of the gas turbine component which concerns on this invention. The perspective view which shows the turbine rotor blade of FIG. The flowchart which shows the procedure which repairs the abrasion part of the turbine rotor blade of FIG. Explanatory drawing which shows the main procedure in FIG. 3 in a cross-sectional state. Explanatory drawing which shows the main procedure of the repair procedure of the turbine rotor blade which 2nd Embodiment performs in the abrasion part repair method of the gas turbine component which concerns on this invention in a cross-sectional state. FIG. 6 is a view taken along the arrow VI in FIG. 5, and shows the respective cases where the groove shape is a quadrangular prism shape (A), a triangular prism shape (B), and a cylindrical shape (C). Explanatory drawing which shows the main procedures of the repair procedure of the turbine rotor blade which the modification of 2nd Embodiment of FIG. 5 performs in a cross-sectional state.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[A] First embodiment (FIGS. 1 to 4)
FIG. 1 is a cross-sectional view showing a gas turbine power plant including a turbine rotor blade to be repaired according to the first embodiment in the method for repairing a worn portion of a gas turbine component according to the present invention. As shown in FIG. 1, a gas turbine power plant 10 includes a compressor 11 that compresses outside air, a combustor liner 12 that mixes and burns air pressurized by the compressor 11 and fuel, A transition piece 14 that guides the combustion gas generated in the combustor liner 12 to the gas turbine 15 and a gas turbine 15 that is rotationally driven by the combustion gas that has passed through the transition piece 14 are provided.

  The compressor 11 includes a compressor rotor 18 in which a compressor blade 17 is implanted in a compressor casing 16. A plurality of compressor blades 17 are implanted in the circumferential direction, and constitute a plurality of blade blade rows in the axial direction. A plurality of compressor vanes 19 are arranged inside the compression casing 16 to form a vane cascade. These stator blade cascades and rotor blade cascades are alternately configured in the axial direction. By rotating the compressor rotor blade 17, external air is introduced into the gas turbine power plant 10 while being compressed.

  The combustor liner 12 is composed of, for example, a can-type combustor, and a plurality of combustor liners 12 are equally provided around the compressor 11. In the combustor liner 12, the air pressurized by the compressor and the fuel are mixed and burned to generate combustion gas.

  The transition piece 14 is connected to the outlet side end of the combustor liner 12 and guides the combustion gas from the combustor liner 12 to the gas turbine 15 while rectifying the combustion gas.

  The gas turbine 15 includes a turbine rotor 22 in which turbine blades 21 are implanted in a turbine casing 20. A plurality of turbine rotor blades 21 are implanted in the circumferential direction, and constitute a plurality of stages of rotor blade cascades in the axial direction. A plurality of turbine vanes 23 are arranged on the inner periphery of the turbine casing 20 to form a vane cascade. These stator blade cascades and rotor blade cascades are alternately configured in the axial direction. The combustion gas introduced into the gas turbine 15 is injected into the turbine rotor blade 21 through the turbine stationary blade 23, and the turbine rotor blade 21 and the turbine rotor 22 are rotated. A generator (not shown) connected to the turbine rotor 22 converts rotational energy into electrical energy.

  As shown in FIG. 2, the turbine rotor blade 21 is provided with a platform 26 on the upper surface of the base portion 25, and an angel fin 27 is formed below the platform 26. A blade portion 28 is integrally extended from the platform 26, and a shroud 29 is integrally provided at the tip of the blade portion 28. Moreover, the implantation part 30 is integrally formed from the lower part of the base 25. FIG. The implanted portions 30 of the plurality of turbine blades 21 are engaged with the turbine rotor 22, and these turbine blades 21 are implanted in the turbine rotor 22.

  The plurality of turbine blades 21 are worn and damaged during operation of the gas turbine 15, particularly when the shrouds 29 come into contact with each other. The method of repairing the worn part of the turbine blade 21 as a gas turbine component in the present embodiment particularly repairs the worn part 32 of the shroud 29 in the turbine blade 21 before reaching the life in the actual plant.

  As shown in FIG. 3, the method for repairing the worn part of the turbine rotor blade 21 includes an acceptance inspection step S1, a removal step S2, a molding step S3, a cleaning step S4, a loading step S5, a joining step S6, a surface finishing step S7, a refinishing step. The coating step S8 and the pre-shipment inspection step S9 are performed. Here, the turbine rotor blade 21 uses, for example, a Ni-base superalloy as the base material 31.

  In the acceptance inspection step S1, the turbine rotor blade 21 used in the actual plant is carried in, and in particular, it is inspected whether or not the shroud 29 is damaged by wear. As shown in FIG. 4, when a wear site 32 is confirmed on the base material 31 of the shroud 29 of the turbine blade 21, the turbine blade 21 is targeted for repair.

  The removal step S2 is a step of removing the oxide film and the coating layer on the outer surface of the turbine blade 21 to be repaired. A coating layer is applied to the outer surface of the turbine rotor blade 21 for oxidation resistance or heat insulation in order to protect the base material 31 from high-temperature combustion gas. In repairing the turbine rotor blade 21, it is necessary to remove the deteriorated coating layer and apply a new coating layer. First, the deteriorated coating layer is removed. Further, since the surface of the worn part 32 of the turbine blade 21 is oxidized, the oxide layer is removed to repair the worn part 32.

  In the forming step S <b> 3, the wear portion 32 of the base material 31 in the shroud 29 of the turbine rotor blade 21 is processed (for example, cutting) to form the forming portion 33. The forming portion 33 is formed in a planar shape in the first embodiment. Thereafter, in the cleaning step S4, the turbine rotor blade 21 in which the molding portion 33 is formed on the base material 31 is cleaned.

  In the loading step S <b> 5, the repair material 35 is loaded (adhered) to the molding portion 33 of the base material 31 in the shroud 29 of the turbine rotor blade 21 using the paste-like bonding material 34. The repair material 35 is made of a Co-based wear-resistant material having a hardness higher than that of the base 31 (for example, a Ni-base superalloy) of the turbine blade 21. Specifically, the chemical components of the repair material 35 are 0.05 to 0.15% carbon, 19 to 21% chromium, 9.0 to 11.0% nickel, and 14 to 20 tungsten in terms of weight ratio. 16%, manganese is 1.0 to 2.0%, inevitable elements are several%, and the balance is cobalt. In addition, the repair material 35 includes a planar contact surface 36 that comes into contact with the molding portion 33 via a bonding material 34 corresponding to the shape of the molding portion 33 of the base 31 of the turbine rotor blade 21.

  The bonding material 34 is for bonding the contact surface 36 of the repair material 35 to the molding portion 33 of the base material 31 in the shroud 29 of the turbine rotor blade 21. The bonding material 34 is a combination of a low melting point alloy (for example, a low melting point Ni-based alloy) powder that melts by a diffusion heat treatment described later and a high melting point alloy (for example, a high melting point Ni-based alloy) powder that does not melt by the diffusion heat treatment. The powder is further blended with a binder.

  Examples of the low melting point Ni-based alloy include BNi-1, BNi-1A, BNi-2, BNi-3, BNi-4, BNi-5, BNi-6, BNi-7 or Ni-Cr as defined in JIS Z3265. There are -W-Fe-Si-B system, Ni-Si-B system, Ni-Co-Cr-Mo-Fe-B system, Ni-Cr-B system, Ni-Co-Si-B system. Examples of the high melting point Ni-based alloy include Nimonic 263, IN617, IN740, IN738LC, and GTD111 (all trade names). In this embodiment, BNi-5 is used as the low melting point Ni-based alloy, and GTD111 is used as the high melting point Ni-based alloy.

  The joining step S6 is a step in which a plurality of turbine blades 21 in which the repair material 35 is loaded in the molding portion 33 of the base material 31 are put together in a vacuum heat treatment furnace and diffusion heat treatment is performed on these turbine blades. is there. This diffusion heat treatment is preferably performed at a temperature of, for example, 1000 to 2000 ° C. and a holding time of, for example, 20 minutes to 1 hour.

  By this diffusion heat treatment, only the low melting point Ni-based alloy powder in the bonding material 34 is melted, and the base material 31, the repair material 35, and the bonding material 34 of the turbine rotor blade 21 are passed through the molten low melting point Ni-based alloy. The high melting point Ni-base alloy diffuses mutually and is firmly bonded.

  In the surface finishing step S7, surplus joining material 34 protruding from the periphery of the repair material 35 joined to the molding portion 33 of the base material 31 in the shroud 29 of the turbine rotor blade 21 is scraped off to remove the shroud 29 of the turbine rotor blade 21. The initial surface shape. In the recoating step S8, a new coating layer is formed on the surface of the turbine rotor blade 21 that has been surface-finished. In the pre-shipment inspection process S9, the suitability of the turbine rotor blade 21 with the worn portion 32 repaired as described above is inspected.

  By sequentially performing the steps S1 to S9 described above, the repair material 35 made of a Co-based wear-resistant material is formed on the molded portion 33 where the wear portion 32 generated in the shroud 29 of the turbine rotor blade 21 is formed. Thus, the repaired turbine rotor blade 21 diffusion-bonded via the bonding material 34 is obtained.

With the configuration described above, the following effects (1) and (2) are achieved according to the first embodiment.
(1) As shown in FIG. 3 and FIG. 4, the repair material 35 made of a Co-based wear resistant material is diffusion-bonded to the molded portion 33 formed in the wear portion 32 of the shroud 29 of the turbine rotor blade 21. The wear part 32 of the turbine rotor blade 21 can be suitably repaired without causing a crack that occurs when the wear part 32 is repaired by welding.

  (2) Each of the molded portions 33 is formed in the wear portion 32 of the shroud 29 of the plurality of turbine rotor blades 31, and the repair material 35 is loaded (adhered) to each of the molded portions 33 using the bonding material 34. The plurality of turbine blades 21 loaded with the repair material 35 are collectively put into a vacuum heat treatment furnace and subjected to diffusion heat treatment to repair the worn portion 32 of the turbine blade 21. For this reason, it is possible to realize a rational repair as compared with the case where the worn portions 32 of the turbine rotor blade 21 are repaired one by one.

[B] Second Embodiment (FIGS. 5 to 7)
FIG. 5 is an explanatory view showing the main procedure of the turbine blade repair procedure performed by the second embodiment in the gas turbine part wear site repair method according to the present invention in a cross-sectional state. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The wear site repair method of the gas turbine component (for example, turbine blade 21) in the second embodiment is different from the first embodiment in that the wear site 32 of the shroud 29 of the turbine blade 21 is processed in the molding step S3. The molding part 40 to be molded is a point processed into an uneven shape.

  That is, in the molding step S3 of the second embodiment, when the molded part 40 is molded by processing the wear part 32 generated in the base 31 in the shroud 29 of the turbine rotor blade 21, the molded part 40 is formed into an uneven shape. Process. As shown in FIG. 6, the uneven shape may be a rectangular column groove shape 41 </ b> A (FIG. 6A), a triangular column groove shape 41 </ b> B (FIG. 6B), or a cylindrical groove shape 41 </ b> C (FIG. 6C )). Further, as shown in FIG. 7, the uneven shape of the molded part 40 is a shape in which the cross section of the molded part 40 is a corrugated shape 42.

  Therefore, the repair material 35 loaded (adhered) to the molding part 40 using the bonding material 34 in accordance with the loading step S5 has a contact surface 43 whose groove shape 41A, 41B, 41C or corrugation of the molding part 40 is corrugated. It is formed in a shape that fits and fits the shape 42.

  In the joining step S6, diffusion heat treatment is collectively performed on the plurality of turbine blades 21 in which the repair material 35 is loaded in the molding unit 40 using the joining material 34 in the loading step S5, and the turbine blade 21 in the shroud 29 is subjected to heat treatment. The repair material 35 is diffusion bonded to the base material 31 through the low melting point Ni-based alloy of the bonding material 34.

  Thus, according to the second embodiment, in addition to the same effects as the effects (1) and (2) of the first embodiment, the following effects (3) and (4) are obtained. Play.

  (3) In the forming step S3, the forming portion 40 formed by processing the wear portion 32 of the base 31 in the shroud 29 of the turbine rotor blade 21 is formed into an uneven shape such as the groove shape 41A, 41B, 41C or the corrugated shape 42. The repair material 35 formed in the step S5 is formed into a shape in which the contact surface 43 fits and fits the molding part 40, and is fitted into the molding part 40 and loaded. For this reason, when the turbine blade 21 is put into the vacuum heat treatment furnace in the joining step S6, it is ensured that the repair material 35 moves or falls from the molding portion 40 of the base 31 of the turbine blade 21 by the action of gravity. The repair of the turbine rotor blade 21 can be optimized.

  (4) The molding part 40 molded in the wear part 32 of the base 31 in the shroud 29 of the turbine rotor blade 21 is formed in an uneven shape such as the groove shape 41A, 41B, 41C or the corrugated shape 42, and the repair material 35 The contact surface 43 is formed in a shape that fits and fits the molding part 40, and is fitted into the molding part 40 and loaded. For this reason, the repair material 35 diffusion-bonded to the base material 31 of the turbine blade 21 in this state is used under the action of shearing force when the turbine blade 21 is used as a component of the gas turbine 15. There is an effect that it is joined very firmly without moving.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. Is included in the scope and gist of the invention, and is included in the invention described in the claims and the equivalents thereof.

  For example, in each of the above-described embodiments, the case where the gas turbine component is the turbine blade 21 has been described. However, the present invention may be applied to the turbine stationary blade 23, the combustor liner 12, the transition piece 14, or the like for repair. .

  DESCRIPTION OF SYMBOLS 11 ... Compressor, 12 ... Combustor liner, 14 ... Transition piece, 15 ... Gas turbine, 21 ... Turbine rotor blade (gas turbine part), 23 ... Turbine stationary blade, 31 ... Base material, 32 ... Wear part, 33 ... Molding part 34 ... bonding material 35 ... repair material 36 ... contact surface 40 ... molding part 41A, 41B, 41C ... groove shape 42 ... wave shape 43 ... contact surface S3 ... molding process S5 ... loading Process, S6 ... Joining process.

Claims (4)

A method for repairing a wear part of a gas turbine part for repairing a wear part generated on an outer surface through which combustion gas flows in the gas turbine part,
A molding step of processing the wear part of the gas turbine component to form a molded part;
A loading step of loading a repair material made of an abrasion-resistant material using a bonding material in the molded portion,
A bonding step in which diffusion heat treatment is performed on the gas turbine component loaded with the repair material, and the repair material and the gas turbine component are diffusion bonded through the bonding material;
While having,
In the molding step, the molded part is processed into a concavo-convex shape so that the repair material has a contact surface that fits and fits the molded part,
The repair material is a cobalt-based wear-resistant material having a hardness higher than that of the base material of the gas turbine component, and the chemical components thereof are 0.05 to 0.15% carbon and 19 chromium in weight ratio. ~ 21%, nickel is 9.0 to 11.0%, tungsten is 14 to 16%, manganese is 1.0 to 2.0%, unavoidable elements are several%, and the balance is cobalt. A method for repairing a worn portion of a gas turbine component, which is characterized. The method for repairing a worn portion of a gas turbine component according to claim 1 , wherein the uneven shape of the molded part is a groove shape or a corrugated shape. 3. The gas turbine according to claim 1, wherein the bonding material includes a blended powder in which a low-melting-point alloy powder that melts by diffusion heat treatment and a high-melting-point alloy powder that does not melt by diffusion heat treatment are blended. How to repair worn parts of parts. The method for repairing a worn portion of a gas turbine component according to any one of claims 1 to 3 , wherein the gas turbine component is a turbine rotor blade, a turbine stationary blade, a combustor liner, or a transition piece.

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