Method for manufacturing a turbine blade

Abstract

Method for manufacturing a turbine blade, the method comprising: a brazing treatment for joining a brazing material to a substrate of a turbine blade by heating the substrate with the brazing material placed on it and melting the brazing material after the substrate has been subjected to a solution annealing treatment at a temperature above the solidus temperature of the brazing material; a stabilization treatment for heating the substrate material undergoing brazing; and an aging treatment to heat the substrate material undergoing stabilization treatment at a temperature below the solidus temperature of the brazing material, where the brazing treatment and the stabilization treatment are carried out by means of a sequential heat treatment.

Description

Technical field

[0001] The present invention relates to a method for manufacturing a turbine blade. State of the art

[0002] A gas turbine comprises a compressor, a combustion chamber, and a turbine. The compressor draws in air and compresses it to produce high-temperature, high-pressure compressed air. The combustion chamber combusts the compressed air by adding fuel. As a turbine within a vehicle's airframe, it consists of several guide vanes and rotor blades arranged alternately. Inside the turbine, the rotor blades are rotated by a high-temperature, high-pressure combustion gas generated from the compressed air. This rotation converts thermal energy into rotational energy.

[0003] The turbine blades, such as the guide vanes and rotor blades, are exposed to a high-temperature environment and are therefore made of metallic materials with high heat resistance. When manufacturing the turbine blades, a substrate material is produced by casting, forging, or similar processes and undergoes a heating and solution annealing treatment, as described, for example, in patent document 1. A brazing material is then applied to the substrate and heated. The substrate is subsequently brazed. After cooling, the substrate undergoes heat treatment for stabilization and aging.

[0004] Patent document 2 discloses a method for closing a recess in a workpiece, such as a turbine blade. A solder foil is used to cover the opening of the recess. The solder foil consists of a mixture of a material that does not melt at soldering temperature and a solder material that does melt. This composition prevents cracking caused by shrinkage during cooling. The closing can be carried out during a heat treatment of the workpiece that is already being performed, such as precipitation hardening or solution annealing.

[0005] Patent document 3 describes a heat treatment process for a ruthenium-containing nickel-based single-crystal superalloy to improve its yield strength in a medium temperature range. The process comprises a solution annealing step, a first aging step, and a second aging step. The second aging step is carried out at a temperature in the range of 600–800°C to precipitate a secondary γ' phase at the grain boundaries of the primary γ' phase, thereby increasing the strength in this temperature range.

[0006] Patent document 4 discloses a multiphase intermetallic compound based on Ni3Si-Ni3Ti-Ni3Nb, which exhibits high strength and ductility over a wide temperature range. The compound has a multiphase microstructure consisting of an L12 phase and a D0 24 -phase or from an L12-, D0 24 - and D0 a-phase exists. For its production, a melt with a specific composition is created and then subjected to a homogenization heat treatment to achieve the desired phase distribution.

[0007] Patent document 5 presents a combined device that enables heat treatment and vapor deposition in a single chamber. The device allows for the continuous execution of heat treatment and vapor deposition at temperatures up to 1200°C. Temperature, time, atmosphere (inert gas or vacuum), and cooling rate can be precisely controlled. This enables the efficient combination of processes such as aging or diffusion annealing with a subsequent coating process.

[0008] Patent document 6 describes a method for forming an aluminide coating on a selected area of ​​a heat-resistant superalloy substrate. The method includes exposing the base metal, forming an aluminum film by means of non-aqueous electroplating, and subsequent heat treatment to diffuse the aluminum into the substrate. A non-aqueous plating fluid is used for the electroplating, which is protected from the atmosphere, for example, by an overlying hydrophobic liquid. This method is particularly suitable for the local repair of components such as turbine blades. List of prior art documents Patent Document 1: JP 2002-103031 A Patent document 2: WO 03 / 053622 A1 Patent Document 3: JP 2013-133505 A Patent Document 4: JP 2006-299410 A Patent Document 5: JP 2006-299378 A Patent document 6: EP 2 966 190 A1 Summary of the invention Problem to be solved by the invention

[0009] In the manufacturing process described in patent document 1, the stabilization treatment involves heat treatment at a temperature higher than the liquidus temperature of the brazing material used for brazing. Therefore, when the substrate material undergoing brazing is subsequently stabilized, there is a possibility that the brazing material will remelt upon heating, potentially causing it to fracture. Thus, in the prior art, the stabilization treatment necessitates the laborious process of adding brazing material to the substrate.

[0010] The present invention was made in view of the aforementioned problem and aims to provide a method for manufacturing a turbine blade which is able to reduce the effort in manufacturing steps. Solution to the problem

[0011] The present invention provides a method for manufacturing a turbine blade according to independent claim 1. Advantageous modifications are found in dependent claims 2 to 10.

[0012] A method for manufacturing a turbine blade according to one embodiment of the present invention comprises a brazing treatment for joining a brazing material to a substrate material of a turbine blade by heating the substrate material with the brazing material applied thereto and melting the brazing material; a stabilization treatment for heating the substrate material that has undergone the brazing treatment; and an aging treatment for heating the substrate material that has undergone the stabilization treatment. The brazing treatment and the stabilization treatment are carried out in a single heat treatment.

[0013] According to one embodiment of the present invention, the brazing and stabilization treatments are performed in a single heat treatment. Accordingly, the work of re-adding the brazing material itself is not required. This reduces the effort involved in the manufacturing steps. Furthermore, two treatment types, including brazing and stabilization, are carried out together. Thus, efficient treatment can be achieved in a short period of time.

[0014] Furthermore, the brazing treatment and the stabilization treatment can be carried out at a first temperature above the liquidus temperature of the brazing material, at which a γ' phase precipitated in the substrate material is enlarged.

[0015] According to one embodiment of the present invention, the brazing treatment and the stabilization treatment are carried out in parallel with a single heat treatment. Accordingly, the heat treatment can be performed efficiently.

[0016] Furthermore, the brazing treatment, the stabilization treatment and the aging treatment can be carried out sequentially.

[0017] According to one embodiment of the present invention, the brazing treatment, the stabilization treatment, and the aging treatment are carried out sequentially. This allows the heat treatment period to be shortened.

[0018] Furthermore, an adjustment treatment can be carried out to set a heating temperature for the aging treatment to a second temperature after the brazing treatment and the stabilization treatment have been carried out at the first temperature.

[0019] According to one embodiment of the present invention, during heat treatment, the heating is carried out sequentially by adjusting the heating temperature from the first temperature to the second temperature. Thus, the heat treatment can be carried out efficiently.

[0020] Furthermore, the second temperature can be lower than the first temperature.

[0021] According to one embodiment of the present invention, the heating temperature is reduced from the first temperature to the second temperature. Accordingly, the heat can be used efficiently after the brazing and stabilization treatments have been carried out.

[0022] Furthermore, brazing, stabilization, and aging treatments can be carried out in a pre-defined heating furnace that includes a heating device. During the adjustment treatment, the furnace internal temperature can be lowered by stopping the heating device or by stopping the heating device and supplying cooling air to the heating furnace.

[0023] According to one embodiment of the present invention, when the heating device is stopped to perform the adjustment treatment, a workload, such as cooling work, and temperature control are reduced, and the process can be simplified. Furthermore, if the adjustment treatment is performed by stopping the heating device and supplying cooling air to the heating oven, the temperature of the heating oven can be lowered in a short period of time.

[0024] Furthermore, during the setting process, the heating device can be operated, and the oven internal temperature can rise to the second temperature after the oven internal temperature has been lowered to a third temperature, which is lower than the second temperature.

[0025] According to one embodiment of the present invention, the heat treatment in which the first temperature is changed via the second temperature to the third temperature can be carried out efficiently.

[0026] Furthermore, the process for manufacturing a turbine blade can also include forming a sublayer on the surface of the substrate material using a metallic material with a higher oxidation resistance than the substrate material, and forming a top layer on the surface of the sublayer after its formation. The top layer can be formed after the substrate material has undergone brazing and stabilization treatments, and the aging treatment can be carried out after the top layer has been formed.

[0027] According to one embodiment of the present invention, after the base layer has been formed, the brazing and stabilizing treatments are carried out in a single heat treatment before the top layer is formed. This allows the heat treatment to be carried out efficiently in a short period of time, and cracking in the top layer can be prevented.

[0028] Furthermore, the underlayer can be treated after the brazing and stabilization treatments have been carried out.

[0029] According to one embodiment of the present invention, the base layer is formed after the brazing and stabilization treatments. The top layer is then formed. As described above, other processes, such as heat treatment, are not carried out between the formation of the base layer and the formation of the top layer. This prevents foreign substances and the like from adhering to the surface of the base layer. If foreign substances and the like were to adhere to the surface, the anchoring effect of the base layer would be impaired. As a countermeasure, this modified example prevents foreign substances and the like from adhering to avoid a deterioration of the anchoring effect. This prevents a reduction in the adhesive strength between the base layer and the top layer.

[0030] Furthermore, the process for manufacturing a turbine blade can also include forming the underlayer on the surface of the substrate material using a metallic material with a higher oxidation resistance than the substrate material, and forming the toplayer on the surface of the underlayer after the underlayer has been formed. The toplayer can be formed after the underlayer has been formed and the substrate material has undergone brazing, stabilization, and aging treatments.

[0031] According to one embodiment of the present invention, after the formation of the base layer, the brazing treatment, the stabilizing treatment, and the aging treatment are carried out sequentially before the top layer is formed. Thus, the heat treatment can be carried out efficiently in a short period of time, and spotting and cracking in the top layer can be prevented. Advantageous effect of the invention

[0032] According to the present invention, a method for manufacturing the turbine blade, which is able to reduce the effort in the manufacturing steps, can be provided. Brief description of the drawings Fig. Figure 1 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a first embodiment of the present invention. Fig. Figure 2 is a diagram showing an example of a change over time of a heating temperature in a case where brazing treatment and stabilization treatment are carried out with a single heat treatment. Fig. Figure 3 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a second embodiment of the present invention. Fig. Figure 4 is a diagram illustrating an example of a change in heating temperature over time in a case where brazing, stabilizing and aging treatments are performed sequentially. Fig. Figure 5 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a third embodiment of the present invention. Fig. Figure 6 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a modified example of the present invention. Fig. Figure 7 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a fourth embodiment of the present invention. Fig. Figure 8 is a diagram illustrating another example of a change in heating temperature over time in a case where brazing, stabilizing and aging treatments are performed sequentially. Fig. Figure 9 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in a comparative example. Fig. Figure 10 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in Example 1. Fig. Figure 11 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in Example 2. Description of embodiments

[0033] With reference to the drawings, a method for manufacturing a turbine blade according to embodiments of the present invention is now described. It should be noted that the invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that can be easily replaced by a person skilled in the art or those that are essentially the same. <Erste Ausführungsform>

[0034] Fig. Figure 1 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a first embodiment of the present invention. As shown in Fig. As illustrated in Figure 1, a method for manufacturing a turbine blade according to the first embodiment comprises a step of forming a support material for a turbine blade, such as a guide vane or a rotor blade, of a gas turbine (step S10), a step of subjecting the support material to a solution annealing treatment (step S20), a step of subjecting the support material to a brazing treatment and a stabilization treatment with a single heat treatment (step S30), and a step of subjecting the support material to an aging treatment (step S40).

[0035] In step S10, the core material is formed, which forms a turbine blade, including a guide vane and a rotor blade. The turbine blades are exposed to a high-temperature environment within the gas turbine. Therefore, the core material forming a turbine blade is made of an alloy with high heat resistance, for example, a nickel-based alloy. An example of a nickel-based alloy is one containing: 12.0% to 14.3% Cr; 8.5% to 11.0% Co; 1.0% to 3.5% Mo; 3.5% to 6.2% W; 3.0% to 5.5% Ta; 3.5% to 4.5% Al; 2.0% to 3.2% Ti; 0.04% to 0.12% C; and 0.005% to 0.05% B. and as a remainder, Ni and unavoidable impurities. Furthermore, the Ni-based alloy with the aforementioned composition may contain Zr from 0.001 ppm to 5 ppm.Furthermore, the Ni-based alloy with the aforementioned composition may contain 1 ppm to 100 ppm Mg and / or Ca and may also contain one or more of the following: 0.02% to 0.5% Pt; 0.02% to 0.5% Rh; and 0.02% to 0.5% Re. The Ni-based alloy with the aforementioned composition may satisfy both of these conditions.

[0036] The support material is formed from the aforementioned material by casting, forging, and the like. If the support material is formed by casting, it can be, for example, a conventional casting (CC) material, a directional solidification (DS) material, or a single-crystal (SC) material. A case is described below in which a directional solidification material is used as the support material by way of example. However, the present invention is not limited to this, and a similar description can be given even if the support material is a conventional casting or single-crystal material.

[0037] In the solution annealing treatment in step S20, the precipitate generated in the previous step is solution annealed by heating, and any increase in the constituents is reduced. During the solution annealing treatment, the support material is heated to a temperature of, for example, approximately 1200 °C.

[0038] In the brazing process in step S30, the substrate material with the brazing material applied to it is heated, and the brazing material is melted and bonded to the substrate. For example, a BNi-2 equivalent material is used as the brazing material. In this case, the solidus temperature of the brazing material is approximately 970 °C. The amount of brazing material to be used for the brazing process is determined in advance by conducting tests and the like. During the brazing process, the heat treatment is carried out at an initial temperature T1 at which the brazing material can be melted. The initial temperature T1 can be set, for example, to between 1060 °C and 1100 °C.

[0039] During the stabilization treatment in step S30, the substrate material is heated, and a γ' phase, which is an intermetallic compound within the substrate, is enlarged. This standardizes the size and shape of the γ' phase and other features. For example, the heat treatment during stabilization can be performed at the initial temperature T1, which corresponds to the heating temperature used in brazing.

[0040] In the first embodiment, in step S30, the brazing treatment and the stabilization treatment are carried out with a single heat treatment. Fig. 2 is a diagram illustrating an example of the heat treatment in step S30. Fig. 2. A horizontal axis indicates the time, and a vertical axis indicates the temperature.

[0041] In step S30, the substrate material with the brazing material applied to it is placed in a predefined heating furnace, and the heating process is initiated by activating a heating element of the furnace (time t1). After the heating process begins, the furnace's internal temperature (heating temperature) first rises to a predefined preheating temperature T0. The preheating temperature T0 is set lower than the solidus temperature of the brazing material and can, for example, range from 930 °C to 970 °C. When the furnace's internal temperature reaches the preheating temperature T0 (time t2), the temperature increase is stopped. Subsequently, the heat treatment (preheating treatment) is carried out at the preheating temperature T0 for a predefined period.With preheating treatment, the temperatures of the substrate material and the brazing material rise uniformly across the entire area, and the temperature difference between the sections is reduced.

[0042] After preheating for a predetermined period (time t3), the furnace internal temperature rises again. When the furnace internal temperature reaches the first temperature T1 (time t4), the temperature increase stops. Subsequently, heat treatment is carried out at the first temperature T1 for a predetermined period. During heat treatment at the first temperature T1, the brazing material is melted and bonded to the substrate. Furthermore, the γ' phase in the substrate can be enlarged, and its size and shape can be standardized. After preheating, heating at the first temperature T1 is carried out, ensuring that each section of the substrate is heated uniformly. This allows for uniform brazing, and the γ' phase is uniformly enlarged in every section of the substrate.After the initial heat treatment at temperature T1 has been carried out for a predetermined period (time t5), the temperature of the substrate material is rapidly reduced to a predetermined cooling temperature (quenching) at a rate of, for example, approximately 30 °C / min. This is achieved, for example, by stopping the heating device and introducing cooling air into the furnace. The quenching treatment maintains the state of the γ' phase (particle diameter, etc.). Subsequently, when the furnace internal temperature has been reduced to a predetermined cooling temperature (time t6), the treatment is completed in step S30. As described above, in the first embodiment, the brazing treatment and the stabilization treatment are performed in a single heat treatment.

[0043] During the aging treatment in step S40, the substrate material, which has undergone stabilization, is heated. Consequently, the γ'-phase, which was enlarged during the stabilization treatment, is further enlarged within the substrate material, and a γ'-phase with a smaller diameter than that formed during stabilization is precipitated. This smaller-diameter γ'-phase increases the strength of the substrate material. Thus, during the aging treatment, the smaller-diameter γ'-phase is precipitated to increase the strength of the substrate material. As a result, the strength and ductility of the substrate material are adjusted. In other words, the brazing treatment, the entire stabilization treatment, and the aging treatment are performed in such a way that the precipitation of the γ'-phase can be adjusted while simultaneously achieving the desired strength and ductility.

[0044] In the aging process, for example, heat treatment is carried out at a second temperature T2, which is lower than the first temperature T1, for a predetermined period. The second temperature T2 can be set, for example, to between 830 °C and 870 °C. After the aging process has been carried out for the predetermined period, the temperature of the substrate material is rapidly reduced to a predetermined cooling temperature at a rate of, for example, approximately 30 °C / min (quenching). This is achieved, for example, by stopping the heating element of the furnace and introducing cooling air into the furnace.

[0045] As described above, in the first embodiment, the brazing and solution annealing treatments are performed in a single heat treatment, thus eliminating the need for re-adding the brazing material. This reduces the complexity of the manufacturing steps. Furthermore, two treatment types, including brazing and stabilization, are performed simultaneously. Therefore, efficient treatment can be achieved over a short period. <Zweite Ausführungsform>

[0046] Fig. Figure 3 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a second embodiment of the present invention. As shown in Fig. As illustrated in Figure 3, the process for manufacturing a turbine blade according to the second embodiment comprises, for example, a step of forming the substrate material of a turbine blade (step S110), a step of subjecting the substrate material to solution annealing (step S120), and a step of subjecting the substrate material to brazing, stabilizing, and aging treatments (step S130). Steps S110 and S120 are similar to steps S10 and S20, respectively, in the first embodiment, and therefore a description of them is omitted.

[0047] In the second embodiment, the brazing treatment, the stabilization treatment and the aging treatment are carried out sequentially in step S130. Fig. Figure 4 is a diagram showing an example of the heat treatment in step S130. Fig. 4. A horizontal axis indicates the time, and a vertical axis indicates the temperature.

[0048] In a similar manner to the first embodiment, in step S130 the preheating treatment is carried out at the preheating temperature T0 (from time t1 to time t4), and after the preheating treatment the heat treatment is carried out as brazing treatment and stabilization treatment at the first temperature T1 (from time t4 to time t5).

[0049] After the heat treatment at the first temperature T1 has been carried out for a predetermined period (time t5), a stabilization treatment is performed in which the furnace internal temperature is lowered to the second temperature T2, for example by stopping the operation of the heating device. At this point, the temperature of the substrate material is lowered at a rate of, for example, 3 °C / min to 20 °C / min. Therefore, compared to the first embodiment, the temperature is lowered slowly after the stabilization treatment (time t5 and thereafter).

[0050] When the furnace internal temperature reaches the second temperature T2 (time t7), the heat treatment is performed as an aging treatment in a state where the heating device is operated to adjust the furnace internal temperature to the second temperature T2. Thus, after the stabilization treatment, the furnace internal temperature is changed to the second temperature T2 to perform the aging treatment, and the aging treatment is carried out sequentially without cooling the furnace to a predetermined cooling temperature. As described above, in the second embodiment, the brazing treatment, the stabilization treatment, and the aging treatment are performed sequentially.

[0051] Similar to the first embodiment, in the aging treatment, for example, the heat treatment is carried out at a second temperature T2, which is lower than the first temperature T1, for a predetermined period. The second temperature T2 can, for example, be set to 830 °C to 870 °C. In the second embodiment, even if the temperature is slowly reduced after the stabilization treatment, the γ' phase enlarges, and the γ' phase with a smaller diameter is precipitated during the aging treatment in a manner similar to the quenching process in the first embodiment. Thus, the substrate material with excellent strength and ductility is formed.

[0052] After the aging treatment has been carried out for a predetermined period (time t8), the temperature of the substrate material is rapidly reduced to a predetermined cooling temperature at a rate of, for example, approximately 30 °C / min (quenching). This is achieved, for example, by stopping the heating element of the furnace and introducing cooling air into the furnace. Once the furnace internal temperature has reached a predetermined temperature (time t9), the substrate material is removed from the furnace. The heat treatment is thus completed.

[0053] As described above, in the second embodiment, the brazing, stabilization, and aging treatments are performed sequentially. This further reduces the heat treatment time. Furthermore, after the brazing and stabilization treatments have been carried out at the first temperature T1, the adjustment treatment is performed to set the second temperature, which is the heating temperature for the aging treatment. This allows for efficient use of the heat in the furnace. <Dritte Ausführungsform>

[0054] Fig. Figure 5 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a third embodiment of the present invention. As shown in Fig. As illustrated in Figure 5, the method for manufacturing a turbine blade according to the third embodiment includes, in addition to the steps in the method for manufacturing a turbine blade according to the first embodiment, a step of forming a sublayer and a top layer on the substrate material.

[0055] The bottom layer and the top layer are designed as a thermal barrier layer (TBC) to protect a turbine blade of a gas turbine from high temperatures.

[0056] The method for manufacturing a turbine blade according to the third embodiment comprises, for example, a step of forming the support material of a turbine blade (step S210), a step of subjecting the support material to solution annealing (step S220), a step of forming the underlayer on the support material (step S230), a step of subjecting the support material to brazing and stabilization treatment with a single heat treatment (step S240), a step of forming the top layer on the support material (step S250), and a step of subjecting the support material to aging treatment (step S260).

[0057] Steps S210 and S220 are similar to steps S10 and S20, respectively, in the first embodiment, and therefore their description is omitted. After step S220, before the sublayer is formed, a surface of the substrate material can be subjected to a blasting treatment to roughen the substrate surface, for example, by applying aluminum oxide (Al₂O₃) to the substrate surface. Furthermore, a cleaning treatment can be performed after the blasting treatment to clean the substrate surface.

[0058] In step S230, the underlayer is formed on the surface of the substrate material. The underlayer prevents oxidation of the substrate material and improves the adhesion of the topcoat. For example, an alloy material such as MCrAlY with higher oxidation resistance than the substrate material is used as the underlayer material. In step S230, for example, after the surface of the substrate material has been heated, the aforementioned alloy material, or similar materials, are melted and applied to the surface of the substrate material to form the underlayer.

[0059] After the underlayer has been formed, the brazing and stabilizing treatments are performed in a single heat treatment in step S240. The heat treatment is carried out in a similar sequence to that in step S30 of the first embodiment. Therefore, after the substrate material with the underlayer formed on it has been preheated at preheating temperature T0 (for example, from 930 °C to 970 °C), the heating at the first temperature T1 (for example, from 1060 °C to 1100 °C) is performed. In step S240, the heat treatment is carried out at the temperature described above. Accordingly, the underlayer spreads out on the roughened surface of the substrate material, and the adhesion between the surface of the substrate material and the underlayer is improved.

[0060] After brazing and stabilization, in step S250, the topcoat is formed on a surface of the substrate. This topcoat protects the substrate surface from high temperatures. A material with low thermal conductivity, such as ceramic, is used for the topcoat. For example, a ceramic containing zirconium dioxide as its main component is used. In step S250, the aforementioned material is applied to the substrate surface by atmospheric plasma spraying to form the topcoat.

[0061] After the top layer has formed, the aging treatment is carried out in step S260. Similar to the first embodiment, the aging treatment involves, for example, heat treatment at a second temperature T2, which is lower than the first temperature T1, for a predetermined period. The second temperature T2 can be set, for example, to between 830 °C and 870 °C. It should be noted that the aging treatment can be performed before the top layer is formed. That is, after the brazing and stabilizing treatments, the aging treatment is carried out sequentially. The top layer can then be formed.

[0062] If the substrate material with the top layer formed on it is subjected to heat treatment at a temperature exceeding 870 °C, a stain, crack, or similar defect may form in the top layer. In the third embodiment, after the formation of the substrate, the brazing and stabilizing treatments are performed in a single heat treatment before the top layer is formed. This allows the heat treatment to be carried out efficiently in a short period of time, and cracking in the top layer can be prevented.

[0063] It should be noted that the third embodiment provides an example of a case in which the brazing and stabilizing treatments are carried out after the base layer has been formed. However, the present invention is not limited to this. Fig. Figure 6 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a modified example of the present invention. As shown in Fig. Figure 6 illustrates that in the process for manufacturing a turbine blade according to the modified example, steps S210 and S220 are similar to the third embodiment. However, the following points differ from the third embodiment. That is, after step S220, the brazing and stabilizing treatments are carried out (step S240A), and after the brazing and stabilizing treatments, the underlayer is formed (step S230A). After the underlayer has been formed, the top layer is formed without performing a heat treatment (step S250). Furthermore, similar to the third embodiment, the aging treatment is carried out after the top layer has been formed (step S260).

[0064] After the formation of the base layer and before the formation of the top layer, heat treatment is not carried out to prevent foreign substances and the like from adhering to the surface of the base layer. If foreign substances and the like were to adhere to the surface, the anchoring effect of the base layer would be impaired. As a countermeasure, this modified example prevents foreign substances and the like from adhering to avoid a deterioration of the anchoring effect. This prevents a reduction in the bond strength between the base layer and the top layer. <Vierte Ausführungsform>

[0065] Fig. Figure 7 is a flowchart illustrating an example of a method for manufacturing a turbine blade according to a fourth embodiment of the present invention. As shown in Fig. As illustrated in Figure 7, the method for manufacturing a turbine blade according to the fourth embodiment includes, in addition to the steps in the method for manufacturing a turbine according to the second embodiment, the step of forming the underlayer and the toplayer on the substrate material.

[0066] The method for manufacturing a turbine blade according to the fourth embodiment comprises, for example, a step of forming the support material of a turbine blade (step S310), a step of subjecting the support material to solution annealing treatment (step S320), a step of forming the underlayer on the support material (step S330), a step of subjecting the support material to brazing, stabilizing and aging treatment (step S340) and a step of forming the toplayer on the support material (step S350).

[0067] Steps S310 and S320 are similar to steps S10 and S20, respectively, in the first embodiment. Furthermore, the configuration in which the blasting and cleaning treatments are performed after step S320 and before the formation of the underlayer, and the underlayer is then formed in step S330, is similar to that in the third embodiment.

[0068] After the sublayer has been formed, the brazing, stabilizing, and aging treatments are carried out sequentially in step S340. The heat treatment is performed in a similar sequence to that in step S130 of the second embodiment. Therefore, after the substrate material with the formed sublayer has been preheated at preheating temperature T0 (e.g., from 930 °C to 970 °C), the brazing and stabilizing heat treatments are performed at the first temperature T1 (e.g., from 1060 °C to 1100 °C). The setting treatment is then performed, and the aging heat treatment is carried out sequentially at the second temperature T2 (e.g., from 830 °C to 870 °C). In step S340, the heat treatment is performed at the temperature described above.Accordingly, the underlayer spreads across the roughened surface of the carrier material, and the adhesive strength between the surface of the carrier material and the underlayer is improved.

[0069] After the brazing, stabilization, and aging treatments have been carried out sequentially, the top layer is formed on the surface of the sublayer in step S350. In step S350, the top layer is formed in a similar sequence to step S250 in the third embodiment.

[0070] In the fourth embodiment, after the base layer has been formed, the brazing, stabilizing, and aging treatments are carried out sequentially before the top layer is formed. This allows the heat treatment to be performed efficiently in a short period of time, and prevents staining and cracking in the top layer.

[0071] The technical scope of the present invention is not limited to the embodiments mentioned above and may be modified as necessary without deviating from the scope of protection of the present invention. In the second embodiment described above, after the stabilization treatment and when the adjustment treatment to lower the oven internal temperature to the second temperature T2 is carried out, the support material is cooled at a temperature reduction rate of 3 °C / min to 20 °C / min. However, the present invention is not limited to this example.

[0072] Fig. Figure 8 is a diagram showing another example of a change in furnace internal temperature over time in a case where brazing, stabilizing, and aging treatments are performed sequentially. As in Fig. As shown in Figure 8, the support material can be cooled after the stabilization treatment at a temperature reduction rate of, for example, approximately 30 °C / min, and the heating device can be operated when the temperature of the support material is at a third temperature T3, which is lower than the second temperature T2 (time t10). The third temperature T3 can be set to a temperature of, for example, approximately 530 °C to approximately 570 °C.

[0073] After the heating device has been operated, when the furnace internal temperature rises to reach the second temperature T2 (time t11), the rise is stopped, and the aging treatment is carried out in the heating furnace at the second temperature T2. Subsequently, similar to the second embodiment, after the aging treatment has been carried out for a predetermined period (time t12), the temperature of the substrate material is rapidly reduced (quenched) to a predetermined cooling temperature at a rate of, for example, approximately 30 °C / min. This is achieved, for example, by stopping the heating device of the heating furnace and introducing cooling air into the furnace. Once the furnace internal temperature has changed to a predetermined temperature (time t13), the substrate material is removed from the heating furnace. The heat treatment is thus completed.Even if the temperature changes as described above, the heat treatment period can be shortened. Furthermore, after the brazing and stabilization treatments have been carried out at the first temperature T1, the adjustment treatment is performed to set the second temperature T2, which is the heating temperature for the aging treatment. This allows the heat in the furnace to be used efficiently. It should be noted that after the stabilization treatment, if the substrate material is cooled at a temperature reduction rate of, for example, approximately 30 °C / min to change the furnace internal temperature to the second temperature T2, the aging treatment can be carried out in the furnace at the second temperature T2.

[0074] Furthermore, in the embodiments mentioned above, when the temperature of the substrate material is reduced from the initial temperature T1 during the initial treatment, the heating device is stopped to lower the substrate material's temperature. However, the present invention is not limited to this example. For instance, the heating device can be stopped, and cooling air can be supplied to the heating oven, thus lowering the substrate material's temperature. This allows for an increased rate of temperature reduction, enabling the substrate material's temperature to be lowered in a short period of time. Examples

[0075] Next, examples of the present invention are described. In the examples, several support materials are formed by casting from a nickel-based alloy with the composition described in the embodiments mentioned above. The several support materials are formed as materials for directional solidification. In Example 1, the support material among the several support materials is sequentially subjected to brazing, stabilization, and aging treatments under the conditions described in the above. Fig. The temperature change shown in the second embodiment is performed as described in Figure 4. In Example 1, the first temperature T1 is set to 1090 °C, and the second temperature T2 is set to 860 °C. Furthermore, during the temperature adjustment process from the first temperature T1 to the second temperature T2, the temperature of the support material is reduced at a rate of 5 °C / min.

[0076] Furthermore, in Example 2, the substrate material is sequentially subjected to brazing, stabilization, and aging treatment among the several substrate materials. Fig. The temperature change shown in Figure 8 is performed. In Example 2, the first temperature T1 is set to 1070 °C, and the second temperature T2 is set to 840 °C. Furthermore, during the temperature adjustment process from the first temperature T1 to the second temperature T2, the temperature of the substrate material is reduced at a rate of 15 °C / min.

[0077] Furthermore, in the comparative example, the substrate material is subjected to brazing, stabilization, and aging treatments independently of the other substrate materials. In this example, brazing and stabilization are performed at 1080 °C. After brazing and stabilization, the temperature of the substrate material is reduced at a rate of 30 °C / min. Additionally, aging is performed at 850 °C.

[0078] Fig. Figure 9 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in a comparative example. Fig. Figure 10 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in Example 1. Fig. Figure 11 is a microphotographic view to illustrate a precipitation state of a γ'-phase of a support material of a turbine blade in Example 2.

[0079] As from Fig. As can be seen in Figure 9, in the support material in the comparison example, the γ'-phase, which is precipitated and enlarged by the stabilization treatment, and the γ'-phase with a smaller diameter, which is precipitated by the aging treatment, are present in a balanced manner. In comparison, as shown in Figure 9, the γ'-phase is present in a balanced way in the support material. Fig. 10 and Fig. As can be seen in Figure 11, in the support materials in Example 1 and Example 2, in a similar way to the support material in the comparison example, the γ' phase, which is precipitated and enlarged by the stabilization treatment, and the γ' phase with a smaller diameter, which is precipitated by the aging treatment, are present in a balanced manner.

[0080] Therefore, in the examples, the brazing, stabilization, and aging treatments are performed sequentially. This allows for a reduction in the heat treatment time. Furthermore, the precipitation state of the γ'-phase, which is similar to that in the comparative example where the brazing, stabilization, and aging treatments are performed independently, can be obtained. List of reference symbols T0 preheating temperature T1 First temperature T2 Second Temperature

Claims

[1] Method for manufacturing a turbine blade, comprising: a brazing treatment for joining a brazing material to a substrate of a turbine blade by heating the substrate with the brazing material placed on it and melting the brazing material after the substrate has been subjected to a solution annealing treatment at a temperature above the solidus temperature of the brazing material; a stabilization treatment for heating the substrate material undergoing brazing; and an aging treatment to heat the substrate material undergoing stabilization treatment at a temperature below the solidus temperature of the brazing material, where the brazing treatment and the stabilization treatment are carried out by means of a sequential heat treatment. [2] Method for producing a turbine blade according to claim 1, wherein the brazing treatment and the stabilization treatment are carried out at a first temperature above the liquidus temperature of the brazing material, at which a γ' phase precipitated in the support material is enlarged. [3] Method for manufacturing a turbine blade according to claim 1 or 2, wherein the brazing treatment, the stabilizing treatment and the aging treatment are carried out sequentially. [4] Method for producing a turbine blade according to claim 1 or 2, further comprising an adjustment treatment for adjusting a heating temperature for the aging treatment to a second temperature after the brazing treatment and the stabilization treatment have been carried out at the first temperature. [5] Method for manufacturing a turbine blade according to claim 4, wherein the second temperature is lower than the first temperature. [6] Method for manufacturing a turbine blade according to claim 4 or 5, wherein the brazing treatment, the stabilizing treatment and the aging treatment are carried out in a predetermined heat furnace comprising a heating device, and wherein, during the adjustment treatment, the furnace internal temperature is lowered by stopping the heating device or by stopping the heating device and supplying cooling air to the heat furnace. [7] Method for manufacturing a turbine blade according to any one of claims 4 to 6, wherein during the setting treatment the heating device is operated and the furnace internal temperature rises to the second temperature after the furnace internal temperature has been lowered to a third temperature which is lower than the second temperature. [8] Method for manufacturing a turbine blade according to any one of claims 1 to 7, wherein the method further comprises: the formation of a sublayer on a surface of the substrate material using a metallic material with a higher oxidation resistance property than the substrate material; and the formation of a top layer on a surface of the sublayer after the sublayer has been formed, wherein the top layer is formed after the substrate material has undergone brazing and stabilization treatment, and the aging treatment is carried out after the top layer has been formed. [9] Method for producing a turbine blade according to claim 8, wherein the underlayer is formed after the brazing treatment and the stabilization treatment have been carried out. [10] Method for manufacturing a turbine blade according to any one of claims 1 to 7, wherein the method further comprises: the formation of a sublayer on a surface of the substrate material using a metallic material with a higher oxidation resistance property than the substrate material; and the formation of a top layer on a surface of the sublayer after the sublayer has been formed, the top layer is formed after the base layer has been formed and the substrate material has been subjected to brazing, stabilization and aging treatments.

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