Repair method, program, and repair device

Abstract

The repair method of the present application includes the steps of forming a repair groove on a repair object by removing a crack-containing region containing a crack in the repair object, supplying a powder material to the repair groove, and melting the powder material in the repair groove to additively manufacture a build-up layer, and performing a shot peening process on the build-up layer whenever the build-up layer is formed by a prescribed layering pitch, the shot peening process imparting a residual compressive stress to the build-up layer by applying an impact to the build-up layer.

Description

TECHNICAL FIELD

[0001] The present application relates to a repair method, a program, and a repair device.

[0002] This application claims priority based on Patent Application No. 2024-069732 filed in Japan on April 23, 2024, and the contents thereof are incorporated herein. BACKGROUND

[0003] Turbine blades of gas turbines, aircraft engines, and the like are formed of high-strength materials such as nickel-based superalloy materials. However, these materials have extremely low weldability. Therefore, when a turbine blade is repaired by welding, a high-temperature crack can occur on the turbine blade.

[0004] Patent Literature 1 discloses a repair method of repairing a turbine blade of a gas turbine. The repair method includes a notch portion forming process, a first welding process, and a second welding process. The notch portion forming process removes a crack to form a notch portion. The first welding process fills the notch portion with a first welding material by build-up welding using the first welding material. The second welding process fills the notch portion with a second welding material by build-up welding using the second welding material after the first welding process. The high-temperature strength of the second welding material is higher than the high-temperature strength of the first welding material. Also, the weldability of the first welding material is higher than the weldability of the second welding material. Therefore, the repair method of Patent Literature 1 can absorb a crack caused by residual stress after welding work by the build-up welding portion of the first welding material, and can ensure the strength of the turbine blade by the build-up welding portion of the second welding material.

[0005] PRIOR ART DOCUMENT

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent No. 6734462 SUMMARY

[0008] TECHNICAL PROBLEM TO BE SOLVED BY THE INVENTION

[0009] However, in the repair method of Patent Literature 1, the strength of the build-up welding portion of the first welding material is low. Also, since the first welding material and the second welding material are different materials from the turbine blade main body, the strength can be reduced compared to before the repair. Also, since a heat treatment with a large heat input such as TIG (Tungsten Inert Gas) welding is performed, sometimes the turbine blade cannot be repaired with high precision. Therefore, there is room for improvement in improving the repair precision.

[0010] The present application was made to solve the above problems, and aims to provide a repair method, a program, and a repair device capable of repairing a repair object with high precision.

[0011] Means for solving technical problems

[0012] To solve the above problems, a repair method according to the present application includes the steps of forming a repair groove on a repair object by removing a crack-containing region containing a crack in the repair object, supplying a powder material to the repair groove, melting the powder material in the repair groove to additively manufacture a formed layer, and performing a shot peening process on the formed layer whenever the formed layer forms a prescribed layering pitch, the shot peening process imparting a residual compressive stress to the formed layer by applying an impact to the formed layer.

[0013] A program according to the present application causes a computer to perform the steps of forming a repair groove on a repair object by removing a crack-containing region containing a crack in the repair object, supplying a powder material to the repair groove, melting the powder material in the repair groove to additively manufacture a formed layer, and performing a shot peening process on the formed layer whenever the formed layer forms a prescribed layering pitch, the shot peening process imparting a residual compressive stress to the formed layer by applying an impact to the formed layer.

[0014] A repair device according to the present application includes a groove forming device that forms a repair groove on a repair object by removing a crack-containing region containing a crack in the repair object, an additive manufacturing device that supplies a powder material to the repair groove, melts the powder material in the repair groove to additively manufacture a formed layer, and a shot peening device that performs a shot peening process on the formed layer whenever the formed layer forms a prescribed layering pitch, the shot peening process imparting a residual compressive stress to the formed layer by applying an impact to the formed layer.

[0015] Effects of the Invention

[0016] According to the repair method, program, and repair device of the present application, a repair object can be repaired with high precision. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic configuration diagram of a repair device according to an embodiment of the present application.

[0018] Figure 2 is a schematic diagram showing an example of a shot peening device according to an embodiment of the present application.

[0019] Figure 3 is a schematic diagram showing an example of a shot peening device according to an embodiment of the present application.

[0020] Figure 4 is a control block diagram of a repair device according to an embodiment of the present application.

[0021] Figure 5 is a flowchart showing steps of the repair method according to the embodiment of the present application.

[0022] Figure 6 is a flowchart showing steps of the preparation process according to the embodiment of the present application.

[0023] Figure 7 is a flowchart showing steps of the shot peening process according to the embodiment of the present application.

[0024] Figure 8 is a flowchart showing steps of the finishing process according to the embodiment of the present application.

[0025] Figure 9 is a schematic diagram showing an example of the flow of the repair method according to the embodiment of the present application.

[0026] Figure 10 is a graph showing an example of residual stress of the additive manufacturing portion before the shot peening process according to the embodiment of the present application.

[0027] Figure 11 is a graph showing an example of residual stress of the additive manufacturing portion after the shot peening process is performed only once after the additive manufacturing portion is formed according to the embodiment of the present application.

[0028] Figure 12 is a graph showing an example of residual stress of the additive manufacturing portion in which the shot peening process is performed for each layering pitch according to the embodiment of the present application.

[0029] Figure 13 is a graph showing an example of residual stress of the additive manufacturing portion in which the shot peening process is performed only once after the additive manufacturing portion is formed according to the embodiment of the present application.

[0030] Figure 14 is a graph showing an example of residual stress of the additive manufacturing portion in which the shot peening process is performed for each layering pitch according to the embodiment of the present application.

[0031] Figure 15 is a graph showing an example of residual stress of the additive manufacturing portion in which the laser shot peening process is performed according to the embodiment of the present application.

[0032] Figure 16 is a graph showing an increase in yield strength due to the shot peening process according to the embodiment of the present application.

[0033] Figure 17 is a cross-sectional view showing an example of the repair groove according to the embodiment of the present application.

[0034] Figure 18 This is a hardware structure diagram related to the embodiments of the present invention. Detailed Implementation

[0035] (Repair device)

[0036] Hereinafter, with reference to the figures, the repair apparatus 1, repair method, and procedure according to embodiments of the present invention will be described. The repair apparatus 1 according to this embodiment is used, for example, to repair turbine blades of gas turbines or aircraft engines. Hereinafter, the object repaired by the repair apparatus 1, such as the turbine blade, will be referred to as the repair object 2. The repair object 2 is, for example, formed of a metallic material. Examples of materials for the repair object 2 include high-strength materials such as nickel-based superalloys.

[0037] Hereinafter, the three mutually orthogonal directions are defined as the X direction, Y direction, and Z direction. In one example of this embodiment, the Z direction is the "up-down direction". Furthermore, in this example, the +Z direction is the up direction, and the -Z direction is the down direction. Furthermore, in this example, the X direction and the Y direction are mutually orthogonal horizontal directions.

[0038] The following description uses the case where a crack 2a is generated on the surface of the repair object 2 facing the +Z direction, and the surface of the repair object 2 with the crack 2a extending along the X and Y directions as an example. Furthermore, the region of the repair object 2 containing the crack 2a is defined as the crack-containing region 2b.

[0039] like Figure 1 As shown, the repair device 1 includes a platform 3, a groove forming device 10, an additive manufacturing device 20, a shot peening device 30, a sensor device 40, a moving device 50, and a control unit 60.

[0040] (Platform)

[0041] The stage 3 extends along the X and Y directions. The repair object 2 is placed on the surface of the stage 3 facing the +Z direction. The stage 3 can be fixed or configured to move along the X, Y, and Z directions.

[0042] (Groove forming device)

[0043] The groove forming apparatus 10 forms a repair groove 5 on the object to be repaired 2 by removing the cracked region 2b. The groove forming apparatus 10 includes a cutting tool 11. The groove forming apparatus 10 forms the repair groove 5 by cutting away the object to be repaired using the cutting tool 11. The repair groove 5 opens in the +Z direction. The repair groove 5 can be formed into a bevel shape consisting of flat surfaces or into a curved surface.

[0044] (Additive manufacturing equipment)

[0045] The additive manufacturing apparatus 20 supplies powder material 4 to the repair tank 5 and melts the powder material 4 within the repair tank 5 to perform additive manufacturing on the forming layer 6. Furthermore, the additive manufacturing apparatus 20 can be used not only for repairing the object 2 but also for manufacturing the object 2. The additive manufacturing apparatus 20 includes a powder supply device 21 and a laser scanner 22.

[0046] (Powder supply device)

[0047] The powder supply device 21 is configured to face the stage 3 in the Z direction. That is, the powder supply device 21 is configured to face the object to be repaired 2 in the Z direction. The powder supply device 21 is located on the +Z side of the object to be repaired 2. The powder supply device 21 contains powder material 4 inside. The powder supply device 21 spreads the powder material 4 into a thin layer in the repair groove 5. While moving in the X and Y directions, the powder supply device 21 causes the powder material 4 to fall in the -Z direction. The powder supply device 21 disperses the powder material 4 into the repair groove 5 and evenly spreads the powder material 4 (dispersed type) in the repair groove 5. The powder material 4 is, for example, a metal material.

[0048] (Laser scanner)

[0049] The laser scanner 22 is configured to be opposite the stage 3 in the Z direction. That is, the laser scanner 22 is configured to be opposite the object to be repaired 2 in the Z direction. The laser scanner 22 is positioned on the +Z direction side of the object to be repaired 2. The laser scanner 22 uses one or more laser beams to irradiate the laser beam 23 (forming laser beam) and repeatedly selectively melts the powder material 4, thereby forming a shaped body from the powder material 4. In this embodiment, the laser scanner 22 irradiates the laser beam 23 in the -Z direction toward the powder material 4 laid in the repair groove 5. In addition, the laser scanner 22 does not necessarily irradiate the laser beam 23 parallel to the -Z direction. For example, the laser scanner 22 can irradiate the laser beam 23 in a direction inclined relative to the -Z direction. The powder material 4 in the repair groove 5 is melted by the irradiation heat of the laser beam 23, and a forming layer 6 is formed in the repair groove 5 by additive manufacturing. An additive manufacturing section 7 is formed by stacking the forming layer 6 in the Z direction. This additive manufacturing section 7 is formed to fill the repair groove 5. Hereinafter, the stacking height h1 of the additive manufacturing unit 7 in the stacking direction (Z direction) will be referred to as "stacking height h1".

[0050] (Shot peening device)

[0051] The shot peening device 30 is configured to face the stage 3 in the Z direction. That is, the shot peening device 30 is configured to face the object to be repaired 2 in the Z direction. The shot peening device 30 is positioned on the +Z direction side of the object to be repaired 2. The shot peening device 30 performs shot peening treatment on the forming layer 6. Shot peening treatment refers to the process of spraying abrasive material 31 onto the surface of the object to apply impact to the forming layer 6.

[0052] Here, in the forming layer 6 formed within the repair groove 5, the molten powder material 4 generates residual tensile stress upon solidification. Due to this residual tensile stress, cracks 2a or internal defects may sometimes occur in the forming layer 6. The shot peening device 30 imparts residual compressive stress to the forming layer 6 through shot peening treatment and reduces residual tensile stress, thereby suppressing the generation of cracks 2a or internal defects. In this embodiment, the shot peening device 30 sprays the abrasive material 31 along the -Z direction onto the surface of the forming layer 6 facing the +Z direction to apply impact. Furthermore, the shot peening device 30 does not necessarily spray the abrasive material 31 in a direction parallel to the -Z direction. For example, the shot peening device 30 may also spray the abrasive material 31 in a direction inclined relative to the -Z direction.

[0053] The shot peening apparatus 30 performs shot peening on the surface of the forming layer 6 in the +Z direction whenever the forming layer 6 is formed with a stacking interval h2. The stacking interval h2 referred to here is the length period in the stacking direction (Z direction) where the forming layer 6 is shot peened in the shot peening process of step S7 described later.

[0054] The shot peening method can be selected appropriately based on the specific circumstances. For example, Figure 1 The shot peening apparatus 30 shown is an apparatus for performing ultrasonic shot peening. This shot peening apparatus 30 includes a pin 31A extending along the Z-direction as the blasting material 31. The pin 31A is formed, for example, of a metallic material. The pin 31A is a rod-shaped member extending along the Z-direction. The end face of the pin 31A in the -Z direction is formed into a curved surface convex in the -Z direction. Ultrasonic waves are applied to the pin 31A, causing it to vibrate along the Z-direction. The shot peening apparatus 30 applies an impact in the -Z direction to the formed layer 6 by bringing the vibrating pin 31A into contact with the surface of the formed layer 6.

[0055] And, as Figure 2 As shown, the shot peening device 30 can be, for example, a device for shot peening strengthening. In this case, the shot peening device 30 uses spheres 31B as the blasting material 31. The spheres 31B are, for example, hard spheres. The shot peening device 30 applies an impact in the -Z direction to the formed layer 6 by causing a plurality of spheres 31B to impact the surface of the formed layer 6.

[0056] And, as Figure 3 As shown, the shot peening apparatus 30 can be, for example, a laser shot peening apparatus. In this case, the shot peening apparatus 30 uses a laser beam 31C (a laser beam for shot peening) as the blasting material 31. In laser shot peening, the laser beam 31C is irradiated while a liquid film 32 (e.g., a water film) is formed on the surface of the forming layer 6. As a result, plasma 33 is generated on the surface of the formed body. Then, the vibration of the plasma 33 is reflected to the surface of the forming layer 6 through the liquid film 32. Through the vibration of this plasma 33, an impact in the -Z direction is applied to the forming layer 6.

[0057] (Sensor device)

[0058] The sensor device 40 acquires information about the object to be repaired, such as its shape, internal stress, and presence or absence of damage. For example, the sensor device 40 includes functional units such as a shape measurement sensor 41, a residual stress sensor 42, and a flaw detection sensor 43. The shape measurement sensor 41, for example, acquires an image of the surface of the object to be repaired, or measures the distance in the Z-direction at multiple measurement points on the surface of the object to be repaired using a laser beam (measuring laser beam), thereby measuring the shape of the crack 2a, repair groove 5, and forming layer 6 generated in the object to be repaired. The residual stress sensor 42, for example, irradiates the object to be repaired with X-rays and measures the residual stress at various depth positions (in the illustrated example, positions in the Z-direction). The flaw detection sensor 43 detects damage and defects inside the object to be repaired by irradiating it with radiation and allowing it to pass through. The shape measurement sensor 41, residual stress sensor 42, and flaw detection sensor 43 can be integrated into a single sensor device 40 as shown in this embodiment, or they can be installed separately. Furthermore, the sensor device 40 may also include functional units for acquiring information about the object to be repaired other than those described above.

[0059] (Mobile device)

[0060] The moving device 50 includes a guide rail 51, a first fixture 52, a second fixture 53, a third fixture 54, and a fourth fixture 55. The guide rail 51 extends along the X and Y directions.

[0061] A first fixture 52 is mounted on a guide rail 51. The first fixture 52 extends from the guide rail 51 in the -Z direction. The first fixture 52 is movable along the guide rail 51. A groove forming device 10 is mounted on the first fixture 52. The groove forming device 10 moves in the X and Y directions as the first fixture 52 moves along the guide rail 51. A second fixture 53 is mounted on the guide rail 51. The second fixture 53 extends from the guide rail 51 in the -Z direction. The second fixture 53 is movable along the guide rail 51. A powder supply device 21 is mounted on the second fixture 53. The powder supply device 21 moves in the X and Y directions as the second fixture 53 moves along the guide rail 51.

[0062] A third fixture 54 extends from the guide rail 51 in the -Z direction. The third fixture 54 is movable along the guide rail 51. A shot peening device 30 is mounted on the third fixture 54. The shot peening device 30 moves in the X and Y directions by moving the third fixture 54 along the guide rail 51. A fourth fixture 55 is mounted on the guide rail 51. The fourth fixture 55 extends from the guide rail 51 in the -Z direction. The fourth fixture 55 is movable along the guide rail 51. A sensor device 40 is mounted on the fourth fixture 55. The sensor device 40 moves in the X and Y directions by moving the fourth fixture 55 along the guide rail 51.

[0063] (Control Department)

[0064] like Figure 4 As shown, the control unit 60 is connected to various devices constituting the repair apparatus 1, such as the groove forming apparatus 10, the additive manufacturing apparatus 20, the shot peening apparatus 30, the sensor device 40, and the moving device 50. The control unit 60 can transmit and receive information, signals, and commands with these devices constituting the repair apparatus 1. The control unit 60 controls these devices constituting the repair apparatus 1. For example, the control unit 60 sends a command for additive manufacturing processing to the additive manufacturing apparatus 20, and the additive manufacturing apparatus 20 notifies the control unit 60 that the additive manufacturing processing has ended. Similarly, the control unit 60 sends a command for shot peening processing to the shot peening apparatus 30, and the shot peening apparatus 30 notifies the control unit 60 that the shot peening processing has ended. Furthermore, the control unit 60 controls the groove forming apparatus 10, the additive manufacturing apparatus 20, the shot peening apparatus 30, and the moving device 50 based on information acquired by the sensor device 40.

[0065] (Steps for the repair method)

[0066] The following is for reference. Figures 5-8 Flowchart, Figure 9 The diagram illustrates an example of the repair method. Here, as repair object 2, a rectangular plate-shaped test piece is used, such as... Figure 9 As shown, the repair groove 5 is formed into a bevel shape consisting of multiple flat surfaces. Furthermore, the depth of the repair groove 5 in the Z direction is set to 2.0 mm.

[0067] like Figure 5As shown, a preparatory process (step S1) is first performed. In step S1, some data is acquired; however, here, a test piece of the same material and shape as the actual repair object 2 used in steps S2 and later is used, and a repair groove 5 of the same shape is formed to acquire the data. While it is preferable that the test piece used in step S1 and the actual repair object 2 used in steps S2 and later are of the same material and shape, they are not necessarily required to be the same. Similarly, regarding the repair groove 5, while it is preferable that the repair groove 5 formed in step S1 and the actual repair groove 5 formed in step S2 and later are of the same shape, they are not necessarily required to be the same.

[0068] like Figure 6 As shown, in the preparation process (step S1), for example, the shape, material, additive manufacturing method, and powder material 4 of the object to be repaired 2 are first set (step S10). Here, for example, the same powder material 4 as the material of the object to be repaired 2 is selected. And, as the additive manufacturing technology, for example, powder bed fusion (PBF) is selected. And, the additive manufacturing parameters are set as shown in Table 1.

[0069] [Table 1]

[0070] Furthermore, for example, if the additive manufacturing apparatus 20 forms the additive manufacturing section 7 in the repair groove 5 according to the parameters in Table 1, and the sensor device 40 acquires the residual stress of the additive manufacturing section 7 formed in the repair groove 5 at each depth, then it is possible to acquire, for example, the residual stress of the additive manufacturing section 7 formed in the repair groove 5 at each depth. Figure 10 The residual stress data shown. Additionally... Figure 10 The data was obtained from the additive manufacturing section 7, which forms multiple molding layers 6 with a thickness of, for example, tens of μm, within the repair groove 5. Figure 10 In the example, residual tensile stress was generated throughout the depth region of the additive manufacturing section 7 from 0 μm to 2000 μm. Specifically, residual tensile stress with a residual stress ratio of approximately +1 to +2 was generated within the depth range of 0 μm to 2000 μm. The residual stress ratio referred to here is, for example, the ratio of the residual stress to a reference value of the tensile stress when the tensile stress is set to positive and the compressive stress to negative. Since residual tensile stress may cause cracks 2a or internal defects in the additive manufacturing section 7, it is necessary to select an appropriate shot peening method and remove the residual tensile stress through shot peening.

[0071] After additive manufacturing step S10, the shot peening method and shot peening conditions are set (step S11). In step S11, the shot peening method is selected by comprehensively considering various conditions such as the time and cost required for shot peening, the shape and material of the object to be repaired 2. The following explanation uses the case where ultrasonic shot peening is selected as the shot peening treatment in step S11 as an example to illustrate the repair method.

[0072] After step S11, the sensor device 40 measures the penetration depth of the residual compressive stress generated by the shot peening process (step S12). In step S12, the shot peening device 30 performs shot peening on the surface of the additive manufacturing section 7 facing the +Z direction only once. Then, the sensor device 40 acquires the residual stress of the additive manufacturing section 7 after shot peening at each depth. Here, for example, in the case of... Figure 10 After shot peening of additive manufacturing section 7, which is formed under the same conditions as the data, residual stress is obtained.

[0073] For example, ultrasonic shot peening is performed on the surface of the additive manufacturing section 7 in the +Z direction using the parameters shown in Table 2. Coverage indicates the proportion at which the same area is repeatedly treated when the shot peening time for the entire area of ​​the treated surface is set to 100%.

[0074] [Table 2]

[0075] Therefore, to obtain Figure 11 The residual stress data shown. Figure 11 In the example, residual compressive stress was generated in the additive manufacturing section 7. Specifically, residual compressive stress with a residual stress ratio of approximately -2 to -4 was generated in the depth range of 0 μm to 500 μm of the additive manufacturing section 7. Furthermore, in the depth range of 500 μm to 2000 μm, the residual compressive stress decreased with increasing depth. Near a depth of 1500 μm, the residual compressive stress approached zero. In the depth range of 1500 μm to 2000 μm, the residual compressive stress had not yet penetrated, and residual tensile stress remained. Figure 11 The penetration depth of the residual compressive stress generated by ultrasonic shot peening was measured to be approximately 1500 μm.

[0076] After step S12, the stacking spacing h2 (the length period of the formed layer 6 in the stacking direction (Z direction) during shot peening) is set (step S13). In step S13, considering the influence of deviation or heat input during additive manufacturing for a penetration depth of 1.5 mm, the control unit 60 sets the stacking spacing h2 to be greater than the melt depth of the formed layer 6 already formed when forming the formed layer 6, and less than the penetration depth of the residual compressive stress generated by shot peening. For example, the stacking spacing h2 is set to 1.0 mm.

[0077] The above steps complete the preparatory processing (step S1).

[0078] return Figure 5 The process involves forming a repair groove 5 after the preparation process (step S1) is completed (step S2). In step S2, the groove forming apparatus 10 forms a repair groove 5 on the repair object 2 by removing the crack-containing region 2b containing the crack 2a of the repair object 2 (see reference). Figure 9 Phase 2).

[0079] After step S2, the control unit 60 evaluates the shape of the repair groove 5 (step S3). In step S3, for example, the sensor device 40 acquires information such as the shape of the repair groove 5, and the control unit 60 obtains information such as the unevenness of the surface of the repair groove 5 and whether there are defects in the repair groove 5 based on the information acquired by the sensor device 40. After step S3, the control unit 60 evaluates the stacking conditions (step S4). In step S4, for example, the control unit 60 calculates the single-layer thickness (stack thickness) and the number of stacks of the forming layer 6 based on the target value of the stacking height h1 of the additive manufacturing unit 7 and the information obtained in step S3. The single-layer thickness of the forming layer 6 is, for example, about 10 μm.

[0080] After step S4, the repair object 2 is set on the repair device 1 (step S5). In step S5, various parameters and the configuration of the repair object 2 can be fine-tuned, for example. Step S5 can also be omitted. After step S5, the control unit 60 sends an additive manufacturing instruction to the additive manufacturing apparatus 20, and the additive manufacturing apparatus 20 performs a lamination process (step S6). In step S6, the additive manufacturing apparatus 20 supplies powder material 4 into the repair tank 5, and melts the powder material 4 in the repair tank 5 through the irradiation heat of the laser beam 23, thereby forming a forming layer 6. The additive manufacturing apparatus 20 forms the forming layer 6 until the lamination spacing h2 (here, 1.0 mm) is reached (see reference). Figure 9 (Section 3). After step S6, a notification that the additive manufacturing process has ended is sent from the additive manufacturing apparatus 20 to the control unit 60, and shot peening is performed (step S7).

[0081] like Figure 7 As shown, in the shot peening process (step S7), firstly, the control unit 60 sends a shot peening instruction to the shot peening device 30, and the shot peening device 30 performs shot peening on the forming layer 6 to apply impact to the forming layer 6 (step S20) (see reference). Figure 9(Section 4). Here, ultrasonic shot peening is performed using the parameters shown in Table 2. Residual compressive stress is applied to the forming layer 6 via step S7. After step S20, the sensor device 40 measures the shot-peened surface (step S21). After step S21, the control unit 60 determines whether the shot-peened surface is within quality control based on the information measured by the sensor device 40 (step S22). If the shot-peened surface is not within quality control (step S22; "No"), the process returns to step S20 and shot peening is performed again. If the shot-peened surface is within quality control (step S22; "Yes"), a notification of shot peening completion is sent from the shot peening device 30 to the control unit 60, and the shot peening process (step S7) ends.

[0082] In addition, in step S7, unevenness is generated on the surface of the forming layer 6 by shot peening, but in step S6, the additive manufacturing apparatus 20 suppresses the effect of unevenness by increasing the heat input of the laser beam 23.

[0083] return Figure 5 In the process, after the shot peening treatment (step S7) is completed, the sensor device 40 acquires information about the repair groove 5 and the forming layer 6. The control unit 60 determines whether the thickness of the forming layer 6 has reached the required stacking height h1 based on the information acquired by the sensor device 40 (step S8). If the thickness of the forming layer 6 has not reached the required stacking height h1 (step S8; "No"), the process returns to step S5. The process from step S5 to step S8 is repeated until the thickness of the forming layer 6 reaches the required stacking height h1 (see reference). Figure 9 (Sections 5-6). Thus, shot peening is performed for each layer spacing h2 (hereinafter referred to as multi-layer shot peening). In this embodiment, the required layer height h1 is 2.0 mm and the layer spacing h2 is 1.0 mm, so the process of steps S5 to S8 is performed twice.

[0084] When the thickness of the forming layer 6 reaches the required stacking height h1 (step S8; "Yes"), the forming layer 6 is stacked to the target stacking height h1, and the additive manufacturing part 7 is formed onto the surface of the repair object 2. After that, a finishing process is performed (step S9).

[0085] like Figure 8As shown, in the finishing process (step S9), for example, the repair object 2 is first subjected to non-destructive testing (step S30). In step S30, for example, the sensor device 40 irradiates the additive manufacturing section 7 with radiation to confirm whether the additive manufacturing section 7 has defects, etc. After step S30, the repair object 2 is subjected to heat treatment (step S31). In step S31, the stress in the repair object 2 is removed. After step S31, the repair object 2 is finished (step S32). In step S32, the excess height of the additive manufacturing section 7 is removed. After step S32, the repair object 2 is subjected to non-destructive testing in the same manner as in step S31 (step S33). If defects or other defects are detected in step S30 or step S33 and the test fails, the additive manufacturing process and multi-layer shot peening process are repeated according to the same steps.

[0086] The finishing process (step S9) is now complete after the above steps. Alternatively, all or part of step S9 may be omitted.

[0087] return Figure 5 The repair process ends after the finishing process (step S9). Through the above steps, the repair of object 2 is completed.

[0088] If, after repair, the residual stress data is obtained following the same steps as in step S12, the result will be as follows: Figure 12 As shown. In Figure 12 In the example, it was confirmed that residual compressive stress was imparted throughout the entire depth range, and residual tensile stress was reduced. Furthermore, it was confirmed that the reduction in residual tensile stress prevented high-temperature cracking and reheat cracking after heat treatment.

[0089] In addition, although ultrasonic shot peening is used as shot peening treatment in the above repair method, shot peening enhancement can also be selected as shot peening treatment.

[0090] In this case, in step S12, for example, if the surface of the additive manufacturing section 7 in the +Z direction is shot-peened with the parameters shown in Table 3, then the following results are obtained: Figure 13 The residual stress data shown. Figure 13 In the example, residual compressive stress was generated in the additive manufacturing section 7. Specifically, residual compressive stress with a residual stress ratio of approximately -2 to -5 was generated in the depth range of 0 μm to 500 μm of the additive manufacturing section 7. Furthermore, in the depth range of 500 μm to 2000 μm, the residual compressive stress decreased with increasing depth. Near a depth of 1500 μm, the residual compressive stress approached zero. In the depth range of 1500 μm to 2000 μm, the residual compressive stress had not yet penetrated, and residual tensile stress remained. Figure 13The penetration depth of the residual compressive stress generated by shot peening was measured to be approximately 1500 μm.

[0091] [Table 3]

[0092] Subsequently, considering a penetration depth of 1.5 mm, the interlayer spacing h2 was set to 1.0 mm, and the repair of object 2 was performed following the same steps as in the ultrasonic shot peening case. After repair, if residual stress data is obtained, then... Figure 14 The data. In Figure 14 In the example, it was confirmed that even with shot peening, residual compressive stress was imparted across the entire depth range, while residual tensile stress was reduced. Furthermore, it was confirmed that the reduction in residual tensile stress prevented high-temperature cracking and reheat cracking after heat treatment.

[0093] Furthermore, laser peening can also be selected as a shot peening process.

[0094] In this case, in step S12, for example, obtaining such Figure 15 The data for residual stress are shown. Figure 15 In the example, residual compressive stress was generated throughout the depth range of 0 μm to 2000 μm in the additive manufacturing section 7. Specifically, a residual compressive stress of approximately -400 μm was generated near the depth of 0 μm in the additive manufacturing section 7, and the residual compressive stress decreased with increasing depth. In laser peening, the residual compressive stress is close to zero near a depth of 2000 μm. Figure 15 The penetration depth of the residual compressive stress generated by laser shot peening was measured to be approximately 2000 μm.

[0095] Subsequently, considering a penetration depth of 2.0 mm, the stacking spacing h2 was set to 2.0 mm, and the repair of object 2 was performed following the same steps as in the ultrasonic shot peening case. Since the stacking height h1 was the same as the stacking spacing h2, only one shot peening treatment (single-layer shot peening) was performed. When the stacking height h1 is greater than 2.0 mm, multiple layers of shot peening are required, similar to ultrasonic shot peening and shot peening strengthening cases. After repair, if residual stress data is obtained, it will be similar to... Figure 15 The same data was obtained. Thus, it was confirmed that even with laser shot peening, residual compressive stress was imparted across the entire depth range, while residual tensile stress was reduced. Furthermore, it was confirmed that the reduction in residual tensile stress prevented high-temperature cracking and reheat cracking after heat treatment.

[0096] Moreover, such as Figure 16 As shown, it was also confirmed that shot peening improved the yield strength. Figure 16 This data comes from ultrasonic shot peening, which is used as a shot peening process. Additionally,Figure 16 The image shows the yield strength ratio after repair on the left and the yield strength ratio before repair on the right. The yield strength ratio referred to here is the ratio of the yield strength to the baseline value, using the yield strength before repair as the baseline value. Figure 16 The yield strength ratio is the ratio of the yield strengths obtained from the repaired portion of repair object 2. From Figure 16 It was confirmed that the yield strength of the repaired object 2 was improved after repair. This is believed to be because the shot peening treatment induced plastic strain in the repaired object 2, thereby promoting recrystallization during heat treatment (step S31).

[0097] (Effects)

[0098] The repair method described above achieves the effects shown below.

[0099] The repair method of this embodiment includes the following steps: forming a repair groove 5 on the repair object 2 by removing the cracked region 2b containing the crack 2a; supplying powder material 4 to the repair groove 5 and melting the powder material 4 in the repair groove 5 to perform additive manufacturing on the forming layer 6; and performing shot peening on the forming layer 6 whenever the forming layer 6 forms a predetermined stacking spacing h2, wherein the shot peening imparts residual compressive stress to the forming layer 6 by applying an impact to the forming layer 6.

[0100] Therefore, the repair apparatus 1 can form the shaped layer 6, for example, using additive manufacturing technology such as Powder Bed Fusion (PBF). The heat input of PBF additive manufacturing technology is less than that of welding such as TIG (Tungsten Inert Gas) welding. Therefore, the residual stress of the repair object 2 is reduced. Furthermore, the repair apparatus 1 can use the same material and the same high-strength powder material 4 as the repair object 2 for repair, thus improving the strength of the repair object 2. Moreover, the repair apparatus 1 can perform shot peening on the surface of the shaped layer 6 at each specified stacking interval h2. As a result, the residual tensile stress in the entire region of the shaped layer 6 is reduced by the residual compressive stress generated by the shot peening. Therefore, since the generation of crack 2a is suppressed, the repair apparatus 1 can perform high-precision repair on the repair object 2. Furthermore, the plastic strain caused by shot peening in the repair object 2 promotes recrystallization during heat treatment (step S31), thus improving the high-temperature material properties.

[0101] The repair method of this embodiment further includes the following steps: setting the stacking spacing h2 to be greater than the melting depth of the formed layer 6 that has been formed when the formed layer 6 is formed, and less than the penetration depth of the residual compressive stress generated by shot peening.

[0102] Therefore, when forming a new forming layer 6, the repair device 1 can suppress the melting of the already shot-peened forming layer 6. Moreover, the residual compressive stress generated by the shot peening process is reliably imparted to the entire area of ​​the forming layer 6. Thus, the repair device 1 can keep time and cost to the necessary minimum and can reduce residual tensile stress throughout the entire area of ​​the forming layer 6.

[0103] In this embodiment, the shot peening method can be appropriately selected based on the circumstances. For example, the shot peening method can be selected by comprehensively considering various factors such as the time and cost required for shot peening, the shape and material of the object to be repaired 2, etc.

[0104] Therefore, selecting the optimal shot peening treatment can improve operational efficiency and reduce costs.

[0105] In the shot peening process of this embodiment, the forming layer 6 can be impacted by ultrasonic shot peening.

[0106] Therefore, compared with other shot peening methods, ultrasonic shot peening can be performed simply and at a low cost. Furthermore, ultrasonic shot peening can treat a wider area in a single pass, thus shortening the operation time. In addition, ultrasonic shot peening can reduce the unevenness of the surface of the forming layer 6.

[0107] Furthermore, in the case of ultrasonic shot peening, the pin 31A is impacted. Therefore, compared to shot peening where numerous spheres 31B are impacted, the peening material 31 does not scatter. Also, there is no need to form a liquid film 32 as in laser shot peening. Therefore, compared to other shot peening methods, ultrasonic shot peening can effectively perform repair work. Furthermore, the surface roughness of the shot-peened surface produced by ultrasonic shot peening is smaller than that of the shot-peened surface, thus improving repair accuracy.

[0108] Furthermore, in the shot peening process of this embodiment, the forming layer 6 can also be subjected to impact through shot peening strengthening.

[0109] Therefore, compared with other shot peening methods, shot peening can be performed simply and at low cost. Furthermore, a wider area can be treated in a single shot peening operation, thus shortening the processing time. Additionally, in the case of shot peening, as described above, a distributed powder material 4 is preferably used, or the heat input for additive manufacturing after shot peening can be increased as needed.

[0110] In the shot peening process of this embodiment, the forming layer 6 can also be impacted by laser shot peening.

[0111] Therefore, compared with other shot peening methods, laser shot peening can perform shot peening with precision and can reduce deformation of the surface of the forming layer 6. Thus, laser shot peening can be carried out even in areas requiring fine and high-precision operations.

[0112] Furthermore, the absolute value of residual stress on the object repaired after laser shot peening is smaller than that of other shot peening methods (e.g., reference). Figure 11 , Figure 13 , Figure 15 Therefore, by selecting laser shot peening, the strength of the repaired object is further improved.

[0113] The repair device 1 also includes: a sensor device 40 for acquiring information about the object to be repaired 2; and a control unit 60 for controlling the additive manufacturing device 20 and the shot peening device 30 based on the information acquired by the sensor device 40.

[0114] Therefore, the repair device 1 can automatically and integrally control the additive manufacturing device 20 and the shot peening device 30 based on the information of the object being repaired 2. This improves work efficiency. Furthermore, it maintains repair accuracy at a certain level regardless of operator skill. Therefore, improved quality can be expected.

[0115] Furthermore, in the example of the above repair method, the case where the repair groove 5 is formed into a bevel shape consisting of flat surfaces has been described, but it is not limited to this. For example, as... Figure 17 As shown, the repair groove 5 can also be formed into a curved surface.

[0116] In this case, since it is not necessary to form the repair groove 5 in a way that the repair groove 5 has a flat surface, the repair groove 5 can be formed simply. Even if the repair groove 5 is formed in a curved shape, shot peening can be performed at each layer spacing h2, thus reducing residual tensile stress and suppressing the generation of crack 2a.

[0117] (Hardware structure)

[0118] The control unit 60 of the above embodiment is installed in such a way as Figure 18 The computer shown is 1100. Figure 18 This is an example of a schematic block diagram showing the structure of a computer 1100 equipped with the control unit 60 according to various embodiments. The computer 1100 includes a processor 1110, a main memory 1120, a storage device 1130, and an interface 1140.

[0119] Furthermore, the operations of each functional unit of the control unit 60 and the aforementioned processing (the processing of the aforementioned repair method) are stored in the storage device 1130 in the form of a program. The processor 1110 reads the program from the storage device 1130 and loads it into the main memory 1120, and executes the aforementioned processing (the processing of the aforementioned repair method) according to the program. In addition, the processor 1110 secures the storage area in the main memory 1120 according to the program.

[0120] The program can be used to implement some of the functions that enable the computer 1100 to perform. For example, the program can function by combining with other programs stored in the storage device 1130 or with other programs installed in other devices. Furthermore, in addition to or instead of the above-described structure, the computer 1100 may also possess a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device). Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 1110 can be implemented through this integrated circuit.

[0121] Examples of storage devices 1130 include magnetic disks, optical disks, and semiconductor memories. Storage device 1130 can be an internal medium directly connected to the bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line. Furthermore, when the program is allocated to computer 1100 via the communication line, the receiving computer 1100 loads the program into main memory 1120 and can execute the aforementioned processing. Storage device 1130 can be a non-temporary tangible storage medium.

[0122] Furthermore, the program can also be a program used to implement some of the aforementioned functions. In addition, the program can also be a so-called differential file (differential program) that implements the above functions by combining with other programs already stored in the storage device 1130.

[0123] (Other implementation methods)

[0124] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments and may include design changes that do not depart from the spirit of the present invention.

[0125] In the above embodiment, the case where the Z direction intersects with the vertical direction is used as an example, but it is not limited to this. The Z direction may also not intersect with the vertical direction.

[0126] In the above embodiment, the example described is that the powder material 4 is the same as the material of the object to be repaired 2, but it is not limited to this. The powder material 4 may also be a different material from the object to be repaired, for example, imparting new functions such as anti-oxidation and wear resistance.

[0127] In the above embodiments, additive manufacturing technology can be used in any manner other than PBF, as long as the heat input is less than that of welding such as TIG welding. The powder supply device 21 may also not be a distribution type, but rather the powder material 4 can be laid in the repair tank 5 by using a scraper of a powder spreader.

[0128] In the above embodiment, the control unit 60 has been described as automatically controlling the slot forming apparatus 10, additive manufacturing apparatus 20, shot peening apparatus 30, and moving device 50 based on information acquired by the sensor device 40, but it is not limited thereto. As in this embodiment, each process of the repair method such as lamination processing and shot peening processing can be executed continuously in the same system, or each process of the repair method such as lamination processing and shot peening processing can be executed in batch processing in each system.

[0129] Furthermore, some or all of the processes in the above-mentioned repair methods can be performed by an operator operating the repair device. Additionally, some of the finishing processes can be performed manually by the operator.

[0130] Furthermore, the additive manufacturing method, shot peening method, material and shape of the object to be repaired, shape of the repair groove, powder material, additive manufacturing parameters, and shot peening parameters are all examples that can be appropriately modified.

[0131] Furthermore, the aforementioned repair device 1 does not need to include all the components described. For example, depending on the convenience of various operations, the trough forming device 10, sensor device 40, etc., can be set as independent devices. In this case, the repair device 1 and the independent devices are preferably connected by the control unit 60, but it is also possible to handle this by performing batch processing separately and inputting the results to the control unit 60.

[0132] Furthermore, step S1 does not need to be performed every time. Figure 6All the steps shown. For example, in the case of repairing object 2 made of the same material multiple times, step S12 can be omitted by reusing the same data.

[0133] <Postscript>

[0134] The repair methods and repair devices 1 described in each embodiment are as follows.

[0135] (1) The repair method involved in the first method includes the following steps: forming a repair groove 5 on the repair object 2 by removing the cracked region 2b containing the crack 2a; supplying powder material 4 to the repair groove 5 and melting the powder material 4 in the repair groove 5 to perform additive manufacturing on the forming layer 6; and whenever the forming layer 6 is formed to a predetermined stacking spacing h2, performing shot peening on the forming layer 6, which imparts residual compressive stress to the forming layer 6 by applying an impact to the forming layer 6.

[0136] Therefore, the surface of the forming layer 6 is shot-peened at each specified lamination spacing h2. Consequently, the residual tensile stress in the entire region of the forming layer 6 is reduced by the residual compressive stress generated by the shot-peening treatment. Therefore, since the formation of crack 2a is suppressed, high-precision repair of the object 2 can be achieved.

[0137] (2) The repair method of the second method is the repair method in (1), which may further include the following steps: setting the layer spacing h2 to be greater than the melting depth of the molten layer 6 formed when the molten layer 6 is formed, and less than the penetration depth of the residual compressive stress generated by the shot peening treatment.

[0138] Therefore, when the new forming layer 6 is formed, the melting of the forming layer 6 that has undergone shot peening is suppressed. Moreover, the residual compressive stress generated by shot peening is reliably imparted to the entire area of ​​the forming layer 6.

[0139] (3) The repair method of the third method is the repair method in (1) or (2), wherein the repair groove 5 can be formed as a curved surface.

[0140] According to this method, since it is not necessary to form the repair groove 5 with a flat surface, the repair groove 5 can be formed simply. Even if the repair groove 5 is formed into a curved surface, shot peening can be performed at each layer spacing h2, thus reducing residual tensile stress and suppressing the generation of crack 2a.

[0141] (4) The repair method of the fourth method is any one of (1) to (3), wherein, in the shot peening process, the forming layer 6 can be impacted by ultrasonic shot peening.

[0142] Compared to other shot peening methods, ultrasonic shot peening offers a simple and cost-effective solution. Furthermore, ultrasonic shot peening can treat a wider area in a single pass, thus reducing operation time. Additionally, ultrasonic shot peening can reduce the unevenness of the surface of the forming layer 6.

[0143] (5) The repair method of the fifth method is any one of (1) to (4), wherein, in the shot peening process, the forming layer 6 can be subjected to impact by shot peening.

[0144] Compared to other shot peening methods, shot peening is a simple and low-cost method. Furthermore, shot peening can treat a wider area in a single operation, thus reducing operation time.

[0145] (6) The repair method of the sixth method is any one of (1) to (5), wherein, in the shot peening process, the forming layer 6 can be impacted by laser shot peening.

[0146] Compared to other shot peening methods, laser shot peening can perform shot peening with precision and reduce deformation of the formed layer 6 surface. Therefore, laser shot peening can be carried out even in areas requiring fine and high-precision operations.

[0147] (7) The procedure of the seventh method causes the computer 1100 to perform the following steps: forming a repair groove 5 on the repair object 2 by removing the cracked region 2b containing the crack 2a; supplying powder material 4 to the repair groove 5 to melt the powder material 4 in the repair groove 5 to perform additive manufacturing on the forming layer 6; and shot peening the forming layer whenever the forming layer 6 forms a predetermined stacking spacing h2, the shot peening applying an impact to the forming layer 6 to impart residual compressive stress to the forming layer 6.

[0148] (8) The repair apparatus 1 of the eighth method comprises: a groove forming apparatus 10, which forms a repair groove 5 on the repair object 2 by removing the cracked region 2b containing the crack 2a; an additive manufacturing apparatus 20, which supplies powder material 4 to the repair groove 5 and melts the powder material 4 in the repair groove 5 to perform additive manufacturing on the forming layer 6; and a shot peening apparatus 30, which performs shot peening on the forming layer 6 whenever the forming layer 6 forms a predetermined stacking spacing h2, the shot peening process imparting residual compressive stress to the forming layer 6 by applying an impact to the forming layer 6.

[0149] (9) The repair device 1 of the ninth method may further include: a sensor device 40 for acquiring information about the object to be repaired 2; and a control unit 60 for controlling the additive manufacturing device 20 and the shot peening device 30 based on the information acquired by the sensor device 40.

[0150] Therefore, the repair device 1 can control the additive manufacturing device 20 and the shot peening device 30 in an integrated and automatic manner based on the information of the object to be repaired 2.

[0151] Industrial availability

[0152] The repair method, procedure, and apparatus of the present invention enable high-precision repair of the object to be repaired.

[0153] Symbol Explanation

[0154] 1-Repair device, 2-Repair object, 2a-Crack, 2b-Cracked area, 3-Stage, 4-Powder material, 5-Repair tank, 6-Forming layer, 7-Additive manufacturing unit, 10-Tank forming device, 11-Cutting tool, 20-Additive manufacturing device, 21-Powder supply device, 22-Laser scanner, 23-Laser beam, 30-Shot peening device, 31-Pulsating material, 31A-Pin, 31B-Sphere, 31C-Laser beam, 32-Liquid film, 33- Plasma, 40-Sensor device, 41-Shape measurement sensor, 42-Residual stress sensor, 43-Flaw detection sensor, 50-Moving device, 51-Guide rail, 52-First fixture, 53-Second fixture, 54-Third fixture, 55-Fourth fixture, 60-Control unit, 1100-Computer, 1110-Processor, 1120-Main memory, 1130-Storage device, 1140-Interface, h1-Stack height, h2-Stack spacing.

Claims

1. A repair method, comprising the following steps: A repair groove is formed on the repair object by removing the cracked area containing the crack. Powder material is supplied to the repair tank, causing the powder material within the repair tank to melt, thereby performing additive manufacturing on the formed layer; and Whenever the forming layer forms a specified stacking spacing, the forming layer is shot peened, and the shot peening process imparts residual compressive stress to the forming layer by applying an impact.

2. The repair method according to claim 1, wherein, It also includes the following steps: The stacking spacing is set to be greater than the melting depth of the formed layer that was formed when the formed layer was formed, and less than the penetration depth of the residual compressive stress generated by the shot peening process.

3. The repair method according to claim 1 or 2, wherein, The repair groove is formed in a curved shape.

4. The repair method according to claim 1 or 2, wherein, In the shot peening process, the formed layer is impacted by ultrasonic shot peening.

5. The repair method according to claim 1 or 2, wherein, In the shot peening process, the formed layer is subjected to impact through shot peening to strengthen it.

6. The repair method according to claim 1 or 2, wherein, In the shot peening process, the formed layer is impacted by laser shot peening.

7. A program that causes a computer to perform the following steps: A repair groove is formed on the repair object by removing the cracked area containing the crack. Powder material is supplied to the repair tank, causing the powder material within the repair tank to melt, thereby performing additive manufacturing on the formed layer; and Whenever the forming layer forms a specified stacking spacing, the forming layer is shot peened, and the shot peening process imparts residual compressive stress to the forming layer by applying an impact.

8. A repair device, comprising: A groove forming apparatus forms a repair groove on a repair object by removing a cracked area containing a crack. An additive manufacturing apparatus supplies powder material into the repair tank, causing the powder material in the repair tank to melt, thereby performing additive manufacturing on the forming layer; as well as A shot peening device performs shot peening on the formed layers whenever the formed layers form a predetermined stacking spacing. The shot peening process imparts residual compressive stress to the formed layers by applying impact to them.

9. The repair apparatus according to claim 8, wherein, It also has: Sensor devices acquire information about the object being repaired; and The control unit controls the additive manufacturing apparatus and the shot peening apparatus based on the information obtained by the sensor device.

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