JP2005098133A - Diffusive brazing repairing method and repairing tool of gas turbine blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diffusive brazing repairing method and a repairing tool of a gas turbine blade, for reducing scattering of a repairing material and generation of a recess-projection, even when a repairing part of the gas turbine blade is large. <P>SOLUTION: The repairing material 2 is inserted into the polished repairing part by polishing a thickness reduced part of the gas turbine blade 1 and its periphery. A guide member 5 is arranged above the repairing material 2 with predetermined clearance 6. These members are inserted into a vacuum furnace, and are held at the predetermined temperature up to completing generation of cracked gas from the repairing material 2. Afterwards, the repairing material 2 is melted by raising the temperature, and is taken out of the vacuum furnace after cooling, and is finished by polishing a projecting part of the repairing part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a diffusion brazing repair method for a gas turbine blade and a repair jig for building up and repairing a thinned portion of a gas turbine blade used in, for example, a generator or an aircraft.

  Since gas turbine blades (blades and nozzles) are used under harsh conditions, the material deteriorates as the operating time increases, and deformations and cracks are generated or thinned. Since the gas turbine blade is an expensive heat-resistant alloy, it is repaired and reused after it has deteriorated, deformed, cracked or thinned, rather than discarded or newly manufactured.

  As a method of repairing the thinned portion of the gas turbine blade, there is diffusion brazing repair. In diffusion brazing repair, mixed powder of base material powder and brazing material powder is used as a repair material such as paste or sheet and placed in the thinned part, and after melting this, melting temperature of boron B, silicon Si, etc. A descending element is diffused to obtain a repaired part close to the base material.

In construction that repairs the tip of the gas turbine rotor blade by overlay welding, for example, the tip is cut or ground into a certain shape before the welding, and then subjected to overlay welding after surface finishing. Yes (see, for example, Patent Document 1). In addition, in the construction for repairing the tip of the gas turbine rotor blade by overlay welding, there is also a construction in which welding is performed while flowing gas or fluid into the air hole inside the rotor blade during construction (see Patent Document 2).
Japanese Patent Laid-Open No. 10-80767 JP-A-10-180442

  However, since the paste-like or sheet-like repair material contains an organic binder, when the entire repair material is heated in a vacuum furnace or the like for diffusion brazing repair, the binder is decomposed and gas is generated. When the thinned part of the gas turbine blade is small, the amount of gas generated is small, so the gas tends to escape through the paste or sheet of repair material, but when the thinned part is large (the surface area is large, the depth In the case of a deep gas), the amount of generated gas increases, so that the gas does not escape almost uniformly through the paste or sheet of repair material, but often concentrates on a certain portion and bumps.

  When the generated gas concentrates and bumps in this way, the paste-like or sheet-like repair material in this portion scatters and the repair material decreases, so that a dent or chipping occurs in the repair portion. Moreover, even when not scattered, extreme unevenness is generated on the surface, and a part where a repair material having a necessary thickness cannot be obtained or a part protruding more than necessary is formed.

  An object of the present invention is to provide a diffusion brazing repair method and a repair jig for a gas turbine blade that cause less scattering of the repair material and occurrence of unevenness even when the repaired portion of the gas turbine blade is large.

  The gas turbine blade diffusion brazing repair method according to the present invention polishes the thinned portion of the gas turbine blade and its periphery, inserts a repair material into the polished repair portion, and maintains a predetermined gap above the repair material. The guide members are placed, inserted into the vacuum furnace, held at a predetermined temperature until the generation of cracked gas from the repair material stops, and then the temperature is increased to melt the repair material, and after cooling, take it out of the vacuum furnace The convex part of the repair part is polished and finished.

  The diffusion brazing repair jig for a gas turbine blade according to the present invention is a guide member that is disposed with a predetermined gap above the repair material inserted in the repair portion of the gas turbine blade and prevents the repair material from scattering. And a spacer for keeping the gap between the guide member and the repair material at a predetermined gap.

ADVANTAGE OF THE INVENTION According to this invention, in the diffusion brazing repair of a gas turbine blade, even when a repair part is large, the diffusion brazing repair method and repair jig with few scattering of a repair material and uneven | corrugated generation | occurrence | production can be provided.

  Embodiments of the present invention will be described below. FIG. 1 is an explanatory view of a diffusion brazing repair method for a gas turbine blade according to a first embodiment of the present invention. The thinned portion of the gas turbine blade 1 and its periphery are smoothed by removing the surface oxide with a grinder. The repair material 2 for the reduced thickness portion is inserted here. Since the volume of the repair material 2 decreases after the heat treatment, an additional repair material 3 is further installed on the repair material 2 in order to compensate for this decrease. As the repair materials 2 and 3, a mixed powder of a powder of the same material as that of the gas turbine blade 1 and a brazing material powder in which boron B and silicon Si are added to lower the melting temperature is formed into a sheet with a binder. Use things. Then, the guide member 5 made of alumina is installed above the additional repair material 3 using the spacer 4. The spacer 4 is used to keep a gap 6 between the guide member 5 and the surface of the gas turbine blade 1 at a predetermined gap.

  Next, these are inserted into a vacuum furnace (not shown), heated to a temperature at which the brazing material in the repair material 2 is melted, and diffusion brazing is performed. In the initial stage of heating, moisture and oil in the binder evaporate, and further heating decomposes the binder component and generates gas. The generated gas is drawn from the gap between the guide member 5 and the repair materials 2 and 3 to an exhaust pump of a vacuum furnace (not shown) and discharged outside the vacuum furnace. This predetermined temperature is maintained until the generated gas is reduced. When the generated gas is reduced and the gas ejection stops, the temperature is further raised and the brazing material is melted. When the brazing material is melted, the temperature is lowered and cooled, and after cooling, the brazing material is taken out from the vacuum furnace, and the convex portion of the repaired portion is polished with a grinder to finish it flat.

  Here, the guide member 5 is provided to prevent the repair material 3 from being scattered by the gas generated from the repair material 3. As described above, moisture and oil in the binder evaporate at the initial stage of heating in the vacuum furnace, and further heating decomposes the binder component and generates gas. At this time, the gas partially concentrates, expands inside the repair material 2 or the additional repair material 3, blows out from the weak portion of the repair material 2, 3, and the repair materials 2, 3 near the ejection part are Jump around. Therefore, a guide member 5 is provided to prevent the repair materials 2 and 3 from scattering. Since the repair materials 2 and 3 that have bounced in the vicinity of the ejection portion are blocked by the guide member 5, they do not scatter.

  In the first embodiment, first, when the thickness of the additional repair material 3 is about 2 mm, the height of the spacer 4 is 3 mm, and the gap 6 between the guide member 5 and the surface of the gas turbine blade 1 is 1 mm. It was confirmed that the guide members 5 can prevent the repair materials 2 and 3 from being scattered. And even when the distance between the guide member 5 and the surface of the gas turbine blade 1 was 0 to 5 mm, it was confirmed that there was no scattering of the repair materials 2 and 3 and that the surface of the repair portion was flattened by the grinder finish. .

  On the other hand, when the gap 6 between the guide member 5 and the surface of the gas turbine blade 1 is larger than 5 mm, the repair materials 2 and 3 are scattered outside the repaired part, and the repaired part surface has large irregularities. After finishing the grinder, it was confirmed that a recessed portion was generated from the desired finished surface. Therefore, the gap 6 between the guide member 5 and the surface of the gas turbine blade 1 is preferably 0 to 5 mm.

  According to 1st Embodiment, since the guide member 5 was installed in the position about 1 mm above the additional repair material 3, scattering of the repair materials 2 and 3 by generation | occurrence | production of the generated gas and generation | occurrence | production of an unevenness | corrugation can be prevented. Further, since alumina is used for the guide member 5, no adhesion of the brazing material occurs, and the guide member 5 can be easily removed even after heat treatment. Moreover, since the guide member 5 can be installed in an appropriate position by adjusting the thickness of the spacer 4 according to the thickness of the repair materials 2 and 3, scattering of the repair materials 2 and 3 can be prevented efficiently.

  Next, a second embodiment of the present invention will be described. FIG. 2 is an explanatory view of a diffusion brazing repair method for gas turbine blades according to a second embodiment of the present invention, FIG. 2 (a) is a side view, and FIG. 2 (b) is a plan view of a guide member 5. It is. The second embodiment is different from the first embodiment shown in FIG. 1 in that the guide member 5 is provided with a gas vent hole 7 for discharging the decomposition gas from the repair materials 2 and 3. is there. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 2A, the repair material 2 is inserted into the thinned portion of the gas turbine blade 1 as in the first embodiment, and the additional repair material 3 is installed on the repair material 2. Then, a guide member 5 is installed above the spacer 4. As shown in FIG. 2B, the guide member 5 is provided with a gas vent hole 7 for discharging the decomposition gas from the repair materials 2 and 3.

  When these are inserted into a vacuum furnace together with the guide member 5 having the gas venting holes 7 and heated, the binder in the repairing materials 2 and 3 is decomposed and a large amount of gas is generated at a lower temperature than the brazing material melts. The generated gas is drawn from the gap between the guide member 5 and the repair materials 2 and 3 to the exhaust pump of the vacuum furnace and discharged out of the vacuum furnace.

  Here, in the case where the gap 6 between the guide member 5 and the repairing materials 2 and 3 is set to a state where there is almost no gap, the generated gas is not properly discharged from the gap 6 because the gas discharge speed is slow. There is a case. Therefore, in the second embodiment, a gas vent hole 7 is provided in the guide member 5 so that the generated gas can be discharged through the gas vent hole 7. When exhaust gas is almost gone, diffusion brazing is performed by raising the temperature further.

  According to the second embodiment, since the gas vent hole 7 is provided in the guide member 5, even if the gap between the guide member 5 and the repair materials 2 and 3 is narrow, the generated gas can be discharged efficiently. For this reason, the holding time until almost no generated gas is eliminated can be shortened. In addition, since almost all the generated gas can be discharged, the generation of voids due to the remaining of the gas in the repair portion is almost eliminated.

  Next, a third embodiment of the present invention will be described. FIG. 3 is an explanatory view of a diffusion brazing repair method for a gas turbine blade according to a third embodiment of the present invention, FIG. 3 (a) is a side view, and FIG. 3 (b) is a plan view of the guide member 5. It is. This third embodiment is different from the first embodiment shown in FIG. 1 in that the guide member 5 is provided with a gas vent groove 8 for discharging the decomposition gas from the repair materials 2 and 3. is there. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 3A, the repair material 2 is inserted into the reduced thickness portion of the gas turbine blade 1 as in the first embodiment, and the additional repair material 3 is installed on the repair material 2. Then, a guide member 5 is installed above the spacer 4. As shown in FIG. 3B, the guide member 5 is provided with gas vent grooves 8 for discharging the decomposition gas from the repair materials 2 and 3 in the vertical and horizontal directions. The vertical and horizontal gas vent grooves 8 are each formed of a 2 mm square groove. Here, ceramic is used as the material of the guide member 5. This is to reduce adhesion of the repair materials 2 and 3. Since the guide member 5 is made of ceramics, it is difficult to process as compared with a metal material. Therefore, instead of the gas vent hole 7, a gas vent groove 8 that is relatively easy to process is used.

  When these are inserted into a vacuum furnace together with the guide member 5 having the gas vent groove 8 and heated, the binder in the repair materials 2 and 3 is decomposed and a large amount of gas is generated at a lower temperature than the brazing material melts. The generated gas is drawn from the gap between the guide member 5 and the repair materials 2 and 3 to the exhaust pump of the vacuum furnace and discharged out of the vacuum furnace.

  Here, in the case where the gap 6 between the guide member 5 and the repairing materials 2 and 3 is set to a state where there is almost no gap, the generated gas is not properly discharged from the gap 6 because the gas discharge speed is slow. There is a case. Further, the repair materials 2 and 3 often adhere to the guide member.

  Therefore, in the third embodiment, the guide member 5 is provided with a gas vent groove 8 so that the generated gas can be discharged through the gas vent groove 8, and the guide member 5 is made of ceramics to be repaired. Adhesion is reduced. When exhaust gas is almost gone, diffusion brazing is performed by raising the temperature further.

  According to the third embodiment, since the gas vent groove 8 is provided in the guide member 5, the generated gas can be discharged efficiently even if the gap between the guide member 5 and the repair materials 2 and 3 is narrow, and the generated gas It is possible to shorten the holding time until almost all of is lost. Moreover, generation | occurrence | production of the void by gas remaining in a repair part can be suppressed. Furthermore, adhesion of the repair members 2 and 3 to the guide member 5 can be reduced. In addition to the gas vent groove 8, a gas vent hole 7 may be provided in the same guide member 5 for use.

  Next, a fourth embodiment of the present invention will be described. FIG. 4 is an explanatory diagram of a diffusion brazing repair method for gas turbine blades according to a fourth embodiment of the present invention. Compared to the first embodiment shown in FIG. 1, the fourth embodiment is such that the guide member 5 is made flexible so that it can be bent along the shape of the repaired portion of the gas turbine blade 1. It is a thing. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The guide member 5 is formed using a thin metal plate having a component / composition close to that of the gas turbine blade 1 and can be easily bent in accordance with the curved surface of the thinned portion of the gas turbine blade 1. The guide member 5 is provided with a gas vent hole 7. The guide member 5 having such flexibility is applied when the thinned portion of the gas turbine blade 1 is a curved surface.

  In FIG. 4, the repair material 2 is inserted into the thinned portion of the gas turbine blade 1 that is a curved surface, and the additional repair material 3 is installed on the repair material 2. Since the repair materials 2 and 3 are formed by forming a metal powder into a sheet shape with an organic binder, the repair materials 2 and 3 can easily follow the curved surface. A guide member 5 is installed via the spacer 4.

  Since the guide member 5 of the fourth embodiment uses a thin metal plate having a component / composition close to that of the gas turbine blade 1, it can be easily bent in accordance with the curved surface of the thinned portion. These are inserted into a vacuum furnace and diffusion brazing is performed.

  FIG. 5 is a plan view showing another example of the guide member 5 having flexibility. The guide member 5 has flexibility and air permeability, and is formed by forming a metal wire similar in material to the gas turbine blade 1 in a net shape. Since the guide member 5 is formed of a net-like metal wire, the guide member 5 is excellent in air permeability, has good exhaustability of the gas generated from the repair materials 2 and 3, and can shorten the gas exhaust time. In addition, residual gas in the repaired portion is reduced, and defects such as voids are less likely to occur. Moreover, since it is net-like and flexible, it can be easily installed along a curved surface.

  It should be noted that the same effect can be obtained by using a cloth formed by knitting ceramic fibers instead of the metal wire. In this case, the effect that the repair materials 2 and 3 are less likely to adhere to the guide member 5 is also obtained. When ceramic fibers are used, the ceramic fibers are soft, so that a metal or ceramic reinforcing material is appropriately disposed on the back side as a backup material.

  According to the fourth embodiment, since the flexible guide member 5 is used, even if the repair portion is a curved surface, it can be easily deformed into a shape along this. In addition, when the guide member 5 having a component / composition close to that of the gas turbine is used, the component / composition close to that of the gas turbine is used even if the brazing material is melted. Will not change significantly. On the other hand, when ceramic fibers are used, the effect that the repair materials 2 and 3 are difficult to adhere to the guide member 5 is obtained.

  Next, FIG. 6 is explanatory drawing of another example of the guide member 5 used for the diffusion brazing repair method of the gas turbine blade of this invention, FIG. 6 (a) is a side view, FIG.6 (b) is FIG. It is a top view. A guide member 5 shown in FIG. 6 has a metal material as a base material and a ceramic coating 9 applied to the side facing the repair materials 2 and 3.

  The main body of the guide member 5 is made of a metal material that does not melt at the diffusion brazing temperature, and the gas vent holes 7 are opened. A ceramic coating 9 such as zirconia is applied to the side of the guide member 5 facing the repair materials 2 and 3. The ceramic coating 9 is deposited by a method such as thermal spraying. The guide member 5 is disposed in the thinned portion of the gas turbine blade 1 while maintaining a predetermined gap 6 by the space 4 as in the above-described embodiments.

  According to the guide member 5 of FIG. 6, since the main body of the guide member 5 is made of a metal material, the guide member 5 can be used repeatedly without being damaged by a sudden temperature change during use. Moreover, since the ceramics to which the repairing materials 2 and 3 are difficult to adhere are coated on the side facing the repairing materials 2 and 3, the repairing materials 2 and 3 are not bonded to the repairing portion. This ceramic coating 9 can withstand temperature changes during use, but even if it is peeled off, it can be reused by thermal spraying again. Since the main body of the guide member 5 is a metal material, it is easy to process in accordance with the repaired portion. After the processing, if the ceramic coating 9 is applied, a guide member having the advantages of the metal material and the ceramic material can be obtained.

Explanatory drawing of the diffusion brazing repair method of the gas turbine blade concerning the 1st Embodiment of this invention. Explanatory drawing of the diffusion brazing repair method of the gas turbine blade concerning the 2nd Embodiment of this invention. Explanatory drawing of the diffusion brazing repair method of the gas turbine blade concerning the 3rd Embodiment of this invention. Explanatory drawing of the diffusion brazing repair method of the gas turbine blade concerning the 4th Embodiment of this invention. The top view which shows another example of the guide member with the flexibility in the 4th Embodiment of this invention. Explanatory drawing of another example of the guide member used for the diffusion brazing repair method of the gas turbine blade of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas turbine blade, 2 ... Repair material, 3 ... Additional repair material, 4 ... Spacer, 5 ... Guide member, 6 ... Gap, 7 ... Gas vent hole, 8 ... Gas vent groove, 9 ... Ceramic coating

Claims (8)

Polishing the thinned part of the gas turbine blade and its surroundings, inserting the repair material into the polished repair part, placing a guide member above the repair material with a predetermined gap, and inserting them into the vacuum furnace And hold at a predetermined temperature until generation of decomposition gas from the repair material stops, then raise the temperature to melt the repair material, take it out from the vacuum furnace after cooling and polish the convex part of the repair part A diffusion brazing repair method for a gas turbine blade, characterized by: The diffusion brazing repair method for a gas turbine blade according to claim 1, wherein the predetermined gap between the guide member and the repair material is 0 to 5 mm. The diffusion brazing repair method for a gas turbine blade according to claim 1 or 2, wherein a gas vent hole for discharging decomposition gas from the repair material is provided in the guide member. The diffusion brazing repair method for a gas turbine blade according to claim 1 or 2, wherein a gas vent groove for discharging decomposition gas from the repair material is provided in the guide member. 5. The diffusion brazing of a gas turbine blade according to claim 1, wherein the guide member is flexible and can be curved along a shape of a repaired portion of the gas turbine blade. Attached repair method. The diffusion brazing repair method for a gas turbine blade according to claim 1, wherein the guide member has flexibility and air permeability. The diffusion brazing of a gas turbine blade according to any one of claims 1 to 4, wherein the guide member is made of a metal material as a base material and ceramic coating is applied to a side facing the repair material. Repair method. A guide member that is disposed with a predetermined gap above the repair material inserted in the repair portion of the gas turbine blade and prevents the repair material from scattering, and a gap between the guide member and the repair material A jig for repairing diffusion brazing of a gas turbine blade, characterized by comprising a spacer for maintaining a gap.

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