JP2010249063A - Damage repairing method of high temperature component and high temperature component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively and quickly repair a plurality of damage generated in a high temperature component. <P>SOLUTION: The damage repairing method of the high temperature component repairs the plurality of damage such as cracks 22 and thinned parts generated in a stator blade 11 of a gas turbine operated in a high temperature state and includes: a repairing material filling step for filling braze-repairing materials 28 in a plurality of cracks 22 of the stator blade 11; a repairing material holding step for covering an exposed portion of the filled braze-repairing material 28 by metal foil 29 and holding the braze-repairing material 28; and a heat treatment step for subjecting the stator blade 11 and the braze-repairing material 28 to dispersion heat treatment and brazing and repairing the plurality of cracks 22. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a damage repairing method for a high-temperature part for repairing damage such as a crack generated in a high-temperature part such as a stationary blade of a gas turbine, and a high-temperature part in which the damage is repaired.

  In a gas turbine power plant, compressed air compressed by driving a compressor provided coaxially with the gas turbine is guided to a combustor and burned together with fuel in a combustion chamber of a combustor liner. The high-temperature combustion gas generated by the combustion is guided to the moving blade through the transition piece and the stationary blade, and the moving blade is driven to rotate so that the work of the gas turbine is performed.

  Ni-based, Co-based, or Ni-Fe-based heat-resistant superalloys are used for combustor liners, transition pieces, stationary blades, and moving blades, which are high-temperature parts of this type of gas turbine. Various damages occur with the operation of the bin. First, since these high-temperature parts are exposed to a high-temperature combustion gas atmosphere, material deterioration occurs, and creeping damage accumulates on the rotor blades due to the action of centrifugal stress caused by high-speed rotation. In addition, high temperature components of gas turbines are subject to thermal fatigue at the stage of transition from a relatively low temperature environment region to a high temperature environment region during start-up and conversely from a high temperature environment region to a low temperature environment region during stoppage, and fatigue damage accumulates. . These damages (material deterioration, creep damage, fatigue damage) accumulate and accumulate.

  By the way, the maintenance management of high-temperature parts of the gas turbine is the same model or the same based on the creep or fatigue life determined at the equipment design stage and the design life set by the actual machine operation and location environment. The gas turbines taking 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 is being implemented. Regardless of the maintenance management method, the high-temperature parts of the gas turbine are repeatedly repaired at regular inspections as necessary, and after reaching the management life, they are uniformly discarded and replaced with very expensive new ones. Is done.

  In the repair of the gas turbine stationary blade at every regular inspection, if a crack has occurred due to use, it can be reused by removing the periphery of the crack and repairing the weld. In addition to welding repairs, there is a method of brazing repairs. A known example (patent document) of welding repair or brazing repair is shown below.

  In Patent Document 1, a Co-based alloy material having excellent creep characteristics, thermal fatigue characteristics and corrosion resistance is used as a repair method for defects generated during precision casting of gas turbine stationary blades for power generation or cracks generated during use. We have proposed a welding method. In Patent Document 2, as a method for repairing a crack generated in a high-temperature metal (alloy) part and filled with a high-temperature corrosion product, the high-temperature corrosion product is immersed in an aqueous solution of sodium hydroxide and / or potassium hydroxide. After removal, the crack is repaired with Ni brazing material or Co brazing material.

  In Patent Document 3, the stationary blade of a jet engine in which a crack has occurred is exposed to a hydrogen atmosphere to reduce the oxide, and acrylic resin and brazing material are applied to the crack as a repair material, and in high temperature and vacuum. Brazing repair. Further, in Patent Document 4, an oxide layer at a surface portion where a crack is generated in a gas turbine stationary blade is shaved so that a part of the crack remains, a repair material is filled in the shaved portion, and an inert gas is filled. The brazing material is melted and the crack is repaired by heat treatment under pressure.

JP-A-11-117705 JP-A-6-234066 JP-A-6-344129 JP 2006-46147 A

  However, in the above-mentioned patent document, especially in the case of crack brazing repair, when the product to be repaired has a complicated shape and cracks have occurred in various parts, it is divided into several times in a posture capable of brazing. Therefore, there is a problem that the repair takes a long time and the repair cost increases.

  An object of the present invention is to provide a high temperature component damage repairing method and a high temperature component capable of reliably and quickly repairing a plurality of damages occurring in a high temperature component.

  A damage repair method for a high-temperature part according to the present invention is a damage repair method for a high-temperature part that repairs a plurality of damages that have occurred in a high-temperature part of an energy engine that is operated in a high-temperature state. A repair material loading step of loading the brazing repair material, a repair material holding step of covering the exposed portion of the loaded brazing repair material with a holding member and holding the brazing repair material, and the high temperature component And a heat treatment step of brazing and repairing the plurality of damages by diffusion heat treatment of the brazing repair material.

  The high-temperature component according to the present invention is a high-temperature component of an energy engine operated in a high-temperature state, wherein the damage is repaired by the high-temperature component damage repair method according to the present invention. It is.

  According to the high temperature component damage repairing method and the high temperature component according to the present invention, the brazing repair material loaded in the plurality of damages generated in the high temperature component is held by the holding member, and then the diffusion heat treatment is performed to perform the multiple damage. Therefore, it is possible to prevent the brazing repair material melted in the diffusion heat treatment from flowing out of the damage. As a result, it is possible to reliably and quickly repair a plurality of damages that have occurred in the high-temperature parts.

The fragmentary sectional view which shows a part of gas turbine to which the damage repair method of the gas turbine stationary blade which is 1st Embodiment in the damage repair method of the high temperature member which concerns on this invention is applied. The perspective view which shows the stationary blade of the gas turbine of FIG. (A)-(E) is process drawing which shows the damage repair procedure of the stationary blade in 1st Embodiment. Sectional drawing after repairing the crack (namely, groove | channel) formed in simulation material with respect to the experimental material of the same material as the stationary blade of FIG. The expanded sectional view which shows the repair part of FIG. FIG. 3 is a cross-sectional view of a stationary blade showing a state immediately before a heat treatment step when repairing a crack generated in the stationary blade of FIG. 2. The expanded sectional view which shows the repair part after completing repair in FIG. Sectional drawing which shows the repair part in the case of completing repair of a crack without using the metal foil of FIG.3 (C). The graph which shows the creep rupture test result of the repair part in 1st Embodiment compared with the case of a base material. The static turbine which shows the state just before the heat treatment process at the time of repairing the crack which arose in the stationary blade by applying the damage repairing method of the gas turbine stationary blade which is the 2nd embodiment in the damage repairing method of the high temperature parts concerning the present invention. Cross section of a wing. Sectional drawing which expands and shows the repair part after completing repair in FIG. The graph which shows the creep rupture test result of the repair part in 2nd Embodiment compared with the case of a base material. A static turbine showing a state immediately before a heat treatment process when repairing a crack generated in a stationary blade by applying a damage repairing method for a gas turbine stationary blade, which is a third embodiment of the damage repairing method for a high-temperature part according to the present invention. Cross section of a wing.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[A] First embodiment (FIGS. 1 to 9)
FIG. 1 is a partial cross-sectional view showing a part of a gas turbine to which a damage repair method for a gas turbine stationary blade according to a first embodiment of the damage repair method for a high temperature member according to the present invention is applied.

  The gas turbine 10 shown in FIG. 1 is an example of an energy engine that is operated in a high temperature state, and compressed air and fuel from a compressor (not shown) are mixed and burned in a combustion chamber of a fuel liner, not shown. The combustion gas is guided to a transition piece (not shown) and a stationary blade 11 and introduced into the moving blade 12 to rotate the turbine rotor 13 in which the moving blade 12 is implanted. The generator and the like are driven to rotate by the rotation of the turbine rotor 13.

  The turbine rotor 13 is configured by connecting a plurality of rotor disks 14 in the axial direction, and a plurality of rotor blades 12 are implanted around each rotor disk 14. Further, the stationary blade 11 is supported by the turbine casing 15 via a shroud segment 16, a retaining ring 17, and a support ring 18. These stationary blades 11 are disposed in front of the rotor blades 12 of the respective rotor disks 14 and constitute turbine stages. The turbine paragraphs are referred to as a first paragraph, a second paragraph, and a third paragraph from the upstream side to the downstream side in the combustion gas flow direction (arrow A).

  The stationary blade 11 in the gas turbine 10 described above is a high-temperature component, and as illustrated in FIG. 2, the two blade portions 21 are integrated with the inner sidewall 19 and the outer sidewall 20. Combustion gas flows between the blade portions 21.

  The stationary blade 11 and the moving blade 12 are made of a heat-resistant superalloy such as a Ni base, a Co base, or a Ni—Fe base. Among these, the stationary blade 11 is a Co base superalloy, and the moving blade 12 is a Ni base. Consists of superalloys. However, the stationary blades 11 and the moving blades 12 are easily damaged due to exposure to high-temperature combustion gas. For example, the blade portion 21, the inner sidewall 19, and the outer sidewall in the stationary blade 11 having a complicated shape. Cracks 22 are likely to occur at each of the 20 locations. Since the stationary blade 11 is composed of an expensive heat-resistant superalloy, it is used for reuse after repairing damage such as the crack 22 unless the damage is fatal.

  In the present embodiment, damage such as a crack is repaired in accordance with the repair procedure of FIG. This repair procedure includes repair pretreatment (FIG. 3 (A)), repair material loading step (FIG. 3 (B)), repair material holding step (FIG. 3 (C)), heat treatment step (FIG. 3 (D)), surface It is an order of a finishing process (Drawing 3 (E)). However, FIG. 3 shows a procedure for repairing the groove 24 simulating the crack 22 formed in the experimental material 23 made of the same material as the stationary blade 11. Accordingly, the pre-repair process is different from that for the stationary blade 11 of the actual plant, but the other processes are the same.

The experimental material 23 is made of a Co-base superalloy similar to the stationary blade 11 of the actual plant, and in particular, the Co-base superalloy FSX414 having the composition shown in Table 1 is used. In the experimental material 23, in order to simulate the crack 22 extending in various depth directions in the stationary blade 11 of the actual plant, for example, grooves 24 are formed on the top surface 25, the left side surface 26, and the right side surface 27 by wire cutting. (FIG. 3A).

  First, the damage repair procedure performed on the experimental material 23 will be described.

  In the pretreatment step (FIG. 3A), the entire experimental material 23 is degreased using, for example, acetone in order to remove oil during the processing of the grooves 24.

  In the next repairing material loading step (FIG. 3B), the brazing repairing material 28 is loaded into all the grooves 24 in the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23. The brazing repair material 28 is a mixture of Ni-based molten alloy powder and Co-based non-molten alloy powder. The Ni-based molten alloy powder is a Ni—Cr—Co—Si—B system and functions as a low melting point brazing material that becomes a molten state in the heat treatment step. Further, the Co-based non-molten alloy powder is a Co—Ni—Cr system and has the same composition as that of the experimental material 23 and does not melt in the heat treatment step. Note that Pt, Ag, or Pb may be used instead of the Ni-based molten alloy.

  In the next repair material holding step (FIG. 3C), all brazing repair materials loaded in the groove 24 on the top surface 25, the groove 24 on the left side surface 26, and the groove 24 on the right side surface 27 in the experimental material 23, respectively. The exposed portion (swelled portion) 28 is covered with a metal foil 29 which is a holding member, and the brazing repair material 28 in each groove 24 is held. In this case, the metal foil 29 is fixed (for example, spot welding) to the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23. The metal foil 29 is preferably a gold foil having a thickness of 0.1 mm or less, for example. The reason why the thickness is set to 0.1 mm or less is to adapt the metal foil 29 to the shapes of the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23 and the complicated surface shape of the stationary blade 11.

  In the next heat treatment step (FIG. 3D), the experimental material 23 that has undergone the repair material holding step is put into a vacuum heat treatment furnace, and diffusion heat treatment is performed on the experimental material 23 and the brazing repair material 28 at, for example, 1200 ° C. Apply. That is, the heating temperature at this time is a temperature at which the Ni-based molten alloy powder of the brazing repair material 28 is melted and the Co-based non-melting alloy powder of the brazing repair material 28 is not melted. The molten Ni-based molten alloy, the non-molten Co-based non-molten alloy powder, and the base material of the experimental material 23 are fixed by a diffusion reaction, and the groove 24 is repaired by brazing. In this heat treatment step, as described above, the brazing repair material 28 is loaded in all the grooves 24 on the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23, and all of these brazing repair materials 28 are removed. This is performed after the metal foil 29 is held.

  In the surface finishing step after this heat treatment step (FIG. 3E), the metal foil 29 is removed from the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23, and the surfaces of these repaired portions are finished. The state after this surface finishing is shown in FIG.

  When the repaired portion of the experimental material 23 after the surface finishing process is observed in a cross section, in each groove 24 which is a simulated crack formed on each of the top surface 25, the left side surface 26, and the right side surface 27 of the experimental material 23, As shown in FIG. 5, the Co-based non-molten alloy powder 30 and the molten Ni-based molten alloy 31 were loaded without having voids (gap). Therefore, it is estimated that the high temperature strength of the repaired portion shows the same level as the non-repaired portion of the experimental material 23.

  Next, a damage repair procedure for the stationary blade 11 (for example, a gas turbine first stage stationary blade) used in an actual plant will be described.

  The stationary blade 11 is made of a Co-base superalloy having a composition equivalent to the composition shown in Table 1, as with the experimental material 23. Further, in the stationary blade 11, cracks 22 extending in different depth directions are generated in the blade portion 21, the inner sidewall 19 and the outer sidewall 20 as shown in FIG. 6 due to long-term use. . These cracks 22 are repaired by a damage repair procedure.

  In the pretreatment process for repairing the stationary blade 11 of the actual plant, the oxide film formed on the surface of the crack 22 to be repaired is removed by performing a heat treatment in a hydrogen atmosphere. By removing the oxide film, the familiarity (adhesion) between the surface of the crack 22 and the brazing repair material 28 is improved.

  After this repair pretreatment step, the repair material loading step of loading all the cracks 22 with the brazing repair material 28, and all these brazing repair materials, as in the case of the test material 23 described above. A repair material holding step of covering and holding the exposed portion of 28 with the metal foil 29, and fixing the Ni-based molten alloy powder and Co-based non-molten alloy powder of the brazing repair material 28 and the base material of the stationary blade 11 by diffusion reaction Then, a heat treatment process for repairing the brazing and a surface finishing process for removing the metal foil 29 and finishing the surface of the stationary blade 11 are sequentially performed.

  When the repaired part where the crack 22 was repaired by the above-described damage repairing procedure was observed, as shown in FIG. 7, the Co-based non-molten alloy powder 30 and the molten Ni-based alloy were cracked in the crack 22 of the stationary blade 11. The molten alloy 31 was filled without having a void (gap). When the crack 22 is repaired without the metal foil 29, as shown in FIG. 8, in the cross section of the repaired portion, between the Co-based non-molten alloy powder 30 and the molten Ni-based molten alloy 31, Void 32 was observed.

  Next, the high temperature strength of the repaired part was confirmed. A first test piece cut out including the repaired portion of the stationary blade 11 repaired as described above, and a second test piece cut out including the repaired portion of the stationary blade 11 repaired without using the metal foil 29. And the creep rupture test was implemented using the 3rd test piece cut out and processed from the base material of the stationary blade 11. FIG. In this test, the test was performed for heating temperatures of 1000 ° C. and 500 ° C. The creep rupture time was significantly lower for the second test piece than for the third test piece, but the first test piece was comparable to the third test piece. Therefore, it was confirmed that the high temperature strength was equivalent to the first test piece and the third test piece.

  From the above, according to the present embodiment, the following effects (1) to (3) are obtained.

  (1) A brazing repair material 28 is loaded into a plurality of cracks 22 having different depths, which are generated at various locations on the stator blade 11 having a complicated shape, and the brazing repair material 28 is loaded with a metal foil 29. After holding, a diffusion heat treatment is performed to repair the plurality of cracks 22 by brazing. For this reason, the metal foil 29 can prevent the molten brazing repair material 28 (Ni-based molten alloy) from flowing out of the crack 22 in the diffusion heat treatment. As a result, there is no void 32 in the repaired portion, and therefore the repaired portion can be secured at a high temperature strength equivalent to that of the base material of the stationary blade 11, so that damage can be repaired reliably. In addition, since the molten brazing repair material 28 is prevented from flowing out by the metal foil 29, a plurality of cracks 22 can be repaired at the same time, so that the plurality of cracks 22 can be repaired quickly. As a result, a plurality of cracks 22 generated in the stationary blade 11 can be repaired reasonably.

  (2) Since the crack 22 generated in the stationary blade 11 is brazed and repaired by using the brazing repair material 28, it is possible to prevent the stator blade 11 from being deformed by repair compared to the repair by welding.

  (3) After the brazing repair material 28 is loaded into all of the plurality of cracks 22 generated in the stationary blade 11 and all these brazing repair materials 28 are held by the metal foil 29, the stationary blade 11 is In the same manner, the brazing repair material 28 is loaded and the brazing repair material 28 is held by the metal foil 29 together with the other stationary blades 11 and put into a vacuum heat treatment furnace, and diffusion heat treatment is performed by batch processing. Can be repaired.

[B] Second Embodiment (FIGS. 10 to 12)
FIG. 10 shows a state immediately before a heat treatment process when repairing a crack generated in a stationary blade by applying a damage repairing method for a gas turbine stationary blade, which is a second embodiment of the damage repairing method for a high-temperature component according to the present invention. It is sectional drawing of the stationary blade which shows a 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 difference between the present embodiment and the first embodiment is the configuration of the holding member. That is, the holding member of the present embodiment employs a ceramic adhesive 33 mainly composed of alumina or silica, and the brazing repair material is covered by the ceramic adhesive 33 covering the exposed portion of the brazing repair material 28. 28 is held.

  Even when the ceramic adhesive 33 is used as a holding member and the crack 22 is repaired, as shown in FIG. 11, the Co-based non-molten alloy powder 30 and the molten Ni-based molten alloy in the stationary blade 11 after the repair. 31 was filled without having a void (gap). Further, when a creep rupture test was carried out using the fourth test piece and the third test piece cut out including the repaired portion of the repaired stationary blade 11, the heating temperature was 1000 as shown in FIG. The creep rupture time was comparable between the fourth test piece and the third test piece in both cases of ° C and 500 ° C. That is, the high temperature strength of the fourth test piece was comparable to that of the third test piece.

  From the above, according to the present embodiment, in addition to the same effects as the effects (1) to (3) of the first embodiment, the following effect (4) is achieved.

  (4) The ceramic adhesive 33 is in the form of a paste, and after the heat treatment process is finished, the strength of the material is reduced and it is easy to peel off. Therefore, the ceramic adhesive 33 can be easily fixed to the surface of the stationary blade 11 and can be removed. . As a result, the workability of repairing the crack 22 can be improved.

[C] Third embodiment (FIG. 13)
FIG. 13 shows a third embodiment of the damage repairing method for high-temperature parts according to the present invention, in which the gas turbine stationary blade damage repairing method is applied and immediately before the heat treatment process when repairing a crack generated in the stationary blade. It is sectional drawing of the stationary blade which shows a state. In the third embodiment, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description is simplified or omitted.

  The difference between the present embodiment and the first and second embodiments is the configuration of the holding member. That is, the holding member 34 according to the present embodiment is obtained by adhering and laminating the ceramic adhesive 33 on the metal foil 29. In this case, the metal foil 29 does not need to be fixed by spot welding or the like as in the first embodiment, and is fixed to the surface of the stationary blade 11 by the laminated ceramic adhesive 33.

  Therefore, also in the present embodiment, the holding member 34 can prevent the molten brazing repair material 28 (that is, the molten Ni-based molten alloy) from flowing out of the crack 22 in the heat treatment step. In addition, the same effects as the effects (1) to (4) of the second embodiment are obtained.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. For example, in the present embodiment, the portion into which the brazing repair material 28 is loaded may be not only the crack 22 but also a plurality of thinned portions recessed in various directions by oxidation or erosion.

  In the present embodiment, the case where the crack 22 or the thinned portion of the stationary blade 11 is repaired has been described. However, the crack 22 or the thinned portion generated in the moving blade 12, the combustor liner, the transition piece, or the like. May be repaired. In this case, particularly in the case of the moving blade 12, since the moving blade 12 is made of a Ni-base superalloy, only the Ni-base molten alloy powder is used for the brazing repair material 28.

  Furthermore, the present invention is a repair method applicable to an energy engine that operates at a high temperature, such as a steam turbine or a jet engine.

10 Gas turbine (energy engine)
11 Stator blade (high temperature parts)
12 Rotor blade (high temperature parts)
19 Inner side wall 20 Outer side wall 21 Wing part 22 Crack (damage)
28 Brazing repair material 29 Metal foil (holding member)
30 Co-based non-molten alloy powder 31 Ni-based molten alloy 33 Ceramic adhesive (holding member)
34 Holding member

Claims (7)

A method for repairing damage to a high-temperature part that repairs multiple damages caused to a high-temperature part of an energy engine operated in a high-temperature state,
A repair material loading step of loading a brazing repair material into the plurality of damages of the high temperature part;
A repair material holding step of covering the exposed portion of the loaded brazing repair material with a holding member and holding the brazing repair material;
A high temperature component damage repairing method comprising: a heat treatment step of performing diffusion heat treatment on the high temperature component and the brazing repair material to braze and repair a plurality of damages. 2. The method of repairing damage to a high-temperature component according to claim 1, wherein the plurality of damages are a plurality of cracks extending in different depth directions or a plurality of thinning portions recessed in different directions. The method for repairing damage to a high-temperature component according to claim 1, wherein the holding member is a metal foil or a ceramic adhesive. The method for repairing damage to a high-temperature component according to claim 1, wherein the holding member is obtained by laminating a ceramic adhesive on a metal foil. 2. The high temperature component according to claim 1, wherein the heat treatment step is performed after a brazing repair material is loaded to all of a plurality of damages in the high temperature component and the brazing repair material is held by a holding member. How to repair damage. The method for repairing damage to a high-temperature component according to claim 1, wherein the high-temperature component is a stationary blade or a moving blade of a gas turbine. A high-temperature part of an energy engine operated in a high-temperature state, wherein the damage is repaired by the damage repair method according to any one of claims 1 to 5.

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