Aero-engine blade thin gasket low deformation repair method

Abstract

The present application relates to a kind of aero-engine blade thin grid low deformation repair method, solve the deformation problem in the batch repair of turbine blade.It includes the following steps:S1.standard processing pretreatment: using numerical control abrasive belt grinding machine, the thickness of grid end face is 0.3~0.6mm after grinding, maximum grinding amount is not more than 1.2mm;S2.laser cleaning: laser cleaning is used to clean the surface of blade grid, repeatedly wash 3~5 times;S3.laser cladding: path automatic planning generates profiled cladding track, using different heterogeneous Rene142 high-temperature alloy powder with matrix, at the same time, through infrared thermometer real-time monitoring temperature around molten pool in cladding process;S4.self-adapting processing forming: using self-adapting abrasive belt polishing equipment to polish laser cladding part;S5.local heat treatment: heated to 700℃±10℃ within 2h±10min, keep warm 2h±10min, argon is filled to 0.15 MPa~0.2 MPa and cooled to below 80℃;S6.nondestructive testing.The present application has the advantages of high precision, excellent performance, strong batch capability and the like.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine maintenance and relates to a method for repairing low-deformation thin-toothed turbine blades of aero-engines. Background Technology

[0002] Turbine rotor blades are key components of aero-engines, operating in harsh environments. The blade tip's service environment is even more severe than that of the blade body, subjecting it not only to high temperatures and drastic changes in working stress but also to corrosion and wear. Wear on the sealing grates of aero-engine turbine blades significantly reduces engine efficiency and blade lifespan, and has always been a major technical challenge for those skilled in the art. Currently, blade tip wear accounts for approximately 90% of typical failures in a certain type of in-service engine, which can have serious consequences: not only will it reduce engine thrust and efficiency, but more importantly, it will drastically increase safety risks. Summary of the Invention

[0003] This invention provides a method for repairing thin-toothed turbine blades with low deformation, thus solving the deformation problem in the batch repair of turbine blades.

[0004] This invention is achieved through the following technical solutions: A method for repairing low-deformation thin-toothed blades of aero-engines includes the following steps: S1. Standard pre-processing: Use a 2MGY5540D CNC belt grinder to process the grates to a uniform size. After grinding, the end face thickness of the grates is 0.3~0.6mm, and the maximum grinding amount does not exceed 1.2mm. S2. Laser Cleaning: The surface of the blade teeth is cleaned using laser cleaning. A 500W pulsed fiber laser (Nd:YAG laser) is used for laser cleaning. The wavelength of the nanosecond-level fiber pulsed laser is 1064 nm, the single pulse width is 100 ns, the maximum single pulse energy is 50 mJ, the spot diameter is 3 mm, the distance between the laser head and the sample is 15 cm, the laser power is 150~160W, the pulse width is 240 ns, the repetition frequency is 500 kHz, the galvanometer scanning speed is 5000 mm / s, the cleaning movement speed is 500~600 mm / min, the spot scanning area covers the teeth, the distance from the top of the teeth is 2 mm, the spot overlap rate is 45~55%, and the cleaning is repeated 3~5 times. S3. Laser Cladding: Blue light 3D scanning with an accuracy of ±0.01mm reconstructs the 3D point cloud model of the ferrule, automatically plans the path to generate a contour cladding trajectory, and uses a different type of Rene142 high-temperature alloy powder than the substrate. The cladding parameters are: layer thickness: 0.5~0.7mm, power: 340~350W, scanning speed: 9~11mm / s, powder feeding rate: 1.5~3.5g / min. At the same time, during the cladding process, the temperature around the molten pool is monitored in real time by an infrared thermometer, and the laser power is dynamically adjusted to ensure that the substrate temperature does not exceed 800℃. S4. Adaptive processing and shaping: Adaptive belt grinding equipment is used to adaptively grind the laser cladding area. The belt linear speed is set to 24~26m / s, the feed rate is 0.05~0.1mm / s, and the surface roughness after processing is below Ra0.8μm. S5. Local heat treatment: Using the Jiaerdun ZWKII30 heat treatment equipment, the heating element and thermocouple are fixed to the repair area of ​​the tooth and placed on the heat-resistant refractory brick. The temperature is heated to 700℃±10℃ within 2h±10min, held for 2h±10min, and then cooled to below 80℃ with argon gas at 0.15 MPa~0.2 MPa. S6. Non-destructive testing: Fluorescent flaw detection and X-ray flaw detection.

[0005] This invention applies to all types of aero-engine compressor rotor blades, including but not limited to: turbofan engines, turboshaft engines, turbojet engines, etc.

[0006] This invention has the advantages of high precision, excellent performance, and strong batch production capability, and has good application prospects in achieving high-precision and high-efficiency repair of thin-tooth blades.

[0007] Beneficial effects of this invention: 1. Laser cleaning is used to treat the substrate before welding: remove the oxide film (20μm thick), make the surface roughness Ra3.2μm, improve the cladding bonding strength, and avoid the hard particles of sandblasting embedding into the substrate or the unevenness of the processed surface caused by manual grinding; 2. Visual recognition-assisted coaxial powder feeding laser cladding technology is adopted, which uses blue light scanning to scan and identify the blade teeth, automatically plans the cladding path, and enhances processing consistency.

[0008] 3. Using dissimilar high-temperature alloy powders different from the base material, the strength of the high-temperature alloy powder after cladding is higher than that of the base material, and the wear resistance of the sieve teeth is improved by about 20%.

[0009] 4. After laser cladding is completed, in-situ local heat treatment is performed to eliminate internal stress in the cladding layer (residual stress reduced by >40%), so as to avoid cracking or deformation caused by internal stress. Attached Figure Description

[0010] Figure 1 A schematic diagram showing the limitation of the laser cladding area and local heat treatment of the blade serrations; Figure 2 A schematic diagram of the laser cleaning area for the blade serrations; Figure 3 This is a metallographic image of the cladding structure. Detailed Implementation

[0011] The following is in conjunction with the appendix Figure 1-3 The technical solution of the present invention will be described in further detail below, but the scope of protection of the present invention is not limited to the following description.

[0012] S1. Standard pre-processing: Using a 2MGY5540D CNC belt grinder, the teeth are machined to a uniform size. After grinding, the end face thickness of the teeth is 0.4mm, and the grinding amount is 1mm. S2. Laser Cleaning: Laser cleaning is used to clean the surface of the blade grates. A 500W pulsed fiber laser (Nd:YAG) is used for laser cleaning. The nanosecond-level fiber pulsed laser has a wavelength of 1064 nm, a single pulse width of 100 ns, a maximum single pulse energy of 50 mJ, a spot diameter of 3 mm, and a laser head-to-sample distance of 15 cm. The laser power is 150W, the pulse width is 240 ns, the repetition rate is 500 kHz, the galvanometer scanning speed is 5000 mm / s, the cleaning movement speed is 500 mm / min, the spot scanning area covers the grates, is 3 mm from the tip of the grates, the spot overlap rate is 50%, and the cleaning is repeated 3 times.

[0013] S3. Laser Cladding: Blue light 3D scanning with an accuracy of ±0.01mm reconstructs the 3D point cloud model of the ferrule, automatically plans the path to generate a contour-following cladding trajectory, and uses a different type of Rene142 high-temperature alloy powder than the substrate (differentiated design). The cladding parameters are: layer thickness: 0.5mm, power: 350W, scanning speed: 10mm / s, powder feed rate: 2.5g / min. Simultaneously, during the cladding process, an infrared thermometer monitors the substrate temperature around the molten pool in real time to ensure that the substrate temperature does not exceed 900℃.

[0014] S4. Adaptive processing and shaping: Adaptive belt grinding equipment is used to adaptively grind the laser cladding area. The belt linear speed is set to 24m / s, the feed rate is 0.05mm / s, and the surface roughness Ra after processing is below 0.8μm.

[0015] S5. Local heat treatment: Using the Jiaerdun ZWKII30 heat treatment equipment, the heating element and thermocouple are fixed on the repair part of the tooth and placed on the heat-resistant refractory brick. The temperature is heated to 700℃±10℃ for 2 hours, held for 2 hours, and then cooled to below 80℃ by argon gas at 0.15 MPa.

[0016] S6. Non-destructive testing: Fluorescent flaw detection and X-ray flaw detection.

[0017] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

[0018] This invention innovates the entire chain of laser cleaning, visual recognition, cladding, and heat treatment processing, overcoming the challenge of deformation control in thin-tooth tooth repair and providing core technical support for extending the service life of aero-engines.

Claims

1. A method for repairing low-deformation thin-toothed blades of aero-engines, characterized in that: Includes the following steps: S1. Standard pre-processing: Use a CNC belt grinder to process the teeth to a uniform size. After grinding, the end face thickness of the teeth is 0.3~0.6mm, and the maximum grinding amount does not exceed 1.2mm. S2. Laser Cleaning: The surface of the blade serrations is cleaned using laser cleaning. A 500W pulsed fiber laser is used for laser cleaning. The nanosecond-level fiber pulsed laser has a wavelength of 1064 nm, a single pulse width of 100 ns, a maximum single pulse energy of 50 mJ, a spot diameter of 3 mm, a laser head-sample distance of 15 cm, a laser power of 150~160 W, a pulse width of 240 ns, a repetition frequency of 500 kHz, a galvanometer scanning speed of 5000 mm / s, a cleaning movement speed of 500~600 mm / min, a spot scanning area covering the serrations, a distance of 2 mm from the top of the serrations, a spot overlap rate of 45~55%, and is repeated 3~5 times. S3. Laser Cladding: Blue light 3D scanning with an accuracy of ±0.01mm reconstructs the 3D point cloud model of the ferrule, automatically plans the path to generate a contour cladding trajectory, and uses a different type of Rene142 high-temperature alloy powder than the substrate. The cladding parameters are: layer thickness: 0.5~0.7mm, power: 340~350W, scanning speed: 9~11mm / s, powder feeding rate: 1.5~3.5g / min. At the same time, during the cladding process, the temperature around the molten pool is monitored in real time by an infrared thermometer, and the laser power is dynamically adjusted to ensure that the substrate temperature does not exceed 800℃. S4. Adaptive processing and shaping: Adaptive belt grinding equipment is used to adaptively grind the laser cladding area. The belt linear speed is set to 24~26m / s, the feed rate is 0.05~0.1mm / s, and the surface roughness after processing is below Ra0.8μm. S5. Local heat treatment: Using heat treatment equipment, the heating element and thermocouple are fixed to the repair area of ​​the tooth and placed on the heat-resistant refractory brick. The temperature is heated to 700℃±10℃ within 2h±10min, held for 2h±10min, and then cooled to below 80℃ by argon gas at 0.15 MPa~0.2MPa. S6. Non-destructive testing.

2. The method for repairing low-deformation thin-toothed aero-engine blades according to claim 1, characterized in that: The model of the CNC belt grinding machine in S1 is 2MGY5540D.

3. The method for repairing low-deformation thin-toothed aero-engine blades according to claim 1, characterized in that: The pulsed fiber laser in S2 is an Nd:YAG laser.

4. The method for repairing low-deformation thin-toothed aero-engine blades according to claim 1, characterized in that: In S5, the heat treatment equipment is model ZWKII30 of Jiaerdun Heat Treatment.

5. The method for repairing low-deformation thin-toothed aero-engine blades according to claim 1, characterized in that: In S6, non-destructive testing is performed using fluorescent testing or X-ray testing.

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