Aero-engine turbine blade crown repairing material and repairing method thereof

Abstract

According to the aero-engine turbine blade crown repairing material and repairing method, the selected cladding powder material and the blade raw material GH105 are similar in performance, the melting temperature and the density of the cladding powder material and the blade raw material GH105 are close, the content of the selected powder material AI and Ti is low, the material welding performance is good, and cracks and other defects are not prone to being generated. A series of repairing processes are set based on the repairing material, and each step aims at recovering the functions of the blade and prolonging the service life of the blade from preliminary grinding to defect removal, heat treatment to material performance improvement, laser cladding repairing and final finishing. Through a series of treatments, the damaged blade can be repaired, the use performance can be recovered, and the damaged blade can be reinstalled for use.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine maintenance, and in particular relates to an aircraft engine turbine blade crown repair material and a repair method thereof. Background Art

[0002] The low-pressure first-stage turbine rotor blades of a certain type of aircraft engine are subjected to direct impact and chemical corrosion from high-temperature combustion gases in a complex and extreme working environment. This not only tests the high-temperature resistance of the material, but also causes frequent vibration and friction interactions between the blade crowns and between the blade crowns and the outer ring. This continuous mechanical and thermal stress causes the sealing tooth area and joint surface (such as the blade crown) of the blade to be damaged shortly after installation. Figure 1 What is more serious is that the sealing teeth are often accompanied by cracks of varying numbers and lengths. These cracks are like potential time bombs, seriously threatening the structural integrity of the blades and the safe operation of the engine. Therefore, such blades can no longer be used and must be repaired or replaced in a timely manner.

[0003] Considering the high cost and maintenance efficiency of aircraft engine parts, it is particularly important to implement effective repair measures on repairable blades compared to directly replacing new blades. Repair can not only significantly reduce overhaul costs and downtime, but also has significant advantages such as short maintenance cycle and high resource utilization. At present, the repair technologies for such blade wear and crack problems mainly include argon arc welding (TIG), micro-beam plasma welding, laser cladding repair and other advanced processes.

[0004] Among these repair methods, argon arc welding with welding wire that matches the composition of the blade base material is a more common choice. However, the materials used for aircraft engine turbine blades are usually rich in elements such as aluminum and titanium. Although these elements give the material excellent high-temperature performance, they also increase the material's crack sensitivity, making the welding process extremely complicated and difficult to control. Specifically, the large heat input during the argon arc welding repair process often leads to a large temperature gradient in the repair area, which can easily cause uneven thickness, large margins, and high residual stresses in the repaired blades, which in turn induce new cracks or the expansion of existing cracks, as well as overall deformation of the blades. These problems seriously affect the quality of the repair, making it difficult to improve the repair qualification rate and meet the needs of large-scale batch repairs and deliveries.

[0005] Therefore, exploring and developing more efficient, low-damage, and high-precision repair technologies, such as optimizing laser cladding parameters to reduce the heat-affected zone, using more advanced welding technologies such as cold spraying or ultrasonic-assisted welding to reduce crack tendency, and strengthening quality inspection and evaluation before and after repair, have become key research directions for improving the success rate of aircraft engine turbine blade repair and extending their service life. Summary of the invention

[0006] The present invention provides an aircraft engine turbine blade crown repair material and a repair method thereof, which solve the problems of uneven thickness, large excess, easy occurrence of cracks, deformation and the like after repair in the existing repair method.

[0007] To achieve the above object, the present invention provides the following technical solutions: An aero-engine turbine blade crown repair material comprises a nickel-based high-temperature alloy powder, the components of which are as follows in percentage by weight: Cr: 18.0~21.0%; Co: 15.0~21.0%; Al: 1.0~2.0%; Ti: 2.0~3.0%; Fe≤1.5%; Si≤0.8%; Mn≤0.4%; Cu≤0.2%; Zr≤0.15%; C≤0.13%; S≤0.015%; P≤0.015%; B≤0.02%; the balance is Ni.

[0008] A method for repairing a turbine blade shroud of an aero-engine, comprising: Grinding to remove wear and crack defects on the sealing teeth of parts; Grind the blade crown joint surface and the air intake side surface of the parts; Heat treatment of parts; Clean the sealing teeth, blade crown joint surface and intake side of the parts after grinding; The blade crown sealing teeth, joint surfaces and air intake side are repaired by laser cladding using repair materials; Secondary milling and grinding of the blade crown joint surface and the intake side surface; Grinding parts such as leaf crown sealing teeth; The parts are clamped and vacuum aged.

[0009] Preferably, the grinding and removal of the wear and crack defects of the sealing teeth of the parts are specifically as follows: Grind the blade parts to remove the worn and cracked parts on the upper part of the sealing teeth, keep the root height 0.2 to 0.5 mm from the top surface of the sealing plate, and perform fluorescence detection until the fluorescence detection is qualified.

[0010] Preferably, the blade crown joint surface and the air intake side surface are ground in the following manner: The worn surfaces of the blade back side, blade basin side joint surface and air intake side are removed to 0.5 mm below the final size. Preferably, the heat treatment of the parts is specifically: vacuum annealing the parts at a vacuum annealing temperature of 1020-1040°C and a holding time of 10-12 minutes.

[0011] Preferably, the cleaning parts sealing teeth, blade crown joint surface and air intake side surface are specifically: Sandblasting is used to remove the oxide layer on the sealing teeth, blade crown joint surface and intake side surface of the parts, and acetone is used to scrub the surface to be clad to clean the parts.

[0012] Preferably, the laser cladding is repaired using a 1000w fiber laser, and the laser cladding process is protected by an argon atmosphere.

[0013] Preferably, the secondary grinding of the blade crown joint surface and the air intake side is specifically as follows: first, grind the cladding material accumulated on the blade crown joint surfaces on both ends of the blade crown exhaust side due to cladding the blade basin and the blade back, then fine-grind the blade crown intake side with the exhaust side edge plate surface as a reference, and finally fine-grind the blade crown joint surfaces on the blade basin side and the blade back side.

[0014] Preferably, the sealing teeth are ground using a shaped grinding wheel.

[0015] Preferably, the vacuum aging temperature is 695-705° C., and the holding time is 960-980 min.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides an aircraft engine turbine blade crown repair material, the cladding powder material selected has similar performance to the blade raw material GH105, the melting temperatures of the two are similar, the densities are relatively close, the selected powder material has low AI and Ti contents, the material has good welding performance, and is not prone to defects such as cracks.

[0017] Furthermore, the present invention also provides a method for repairing the blade crown of an aircraft engine turbine blade. A series of repair processes are set up based on the repair material of the present invention, from preliminary grinding to remove defects, to heat treatment to improve material properties, to laser cladding repair and final finishing, each step is aimed at restoring the function of the blade and extending its service life. Through this series of treatments, the damaged blade can be repaired, its performance restored, and reinstalled for use.

[0018] Furthermore, vacuum annealing can eliminate the internal stress generated in the parts during the processing, improve the microstructure of the material, and reduce the deformation and crack generation during the cladding process.

[0019] Furthermore, surface cleaning ensures the surface cleanliness before laser cladding, removes the oxide layer and impurities that may affect the cladding quality, and improves the bonding strength and overall quality of the cladding layer.

[0020] Furthermore, the use of high-power fiber lasers for laser cladding can achieve fast and precise repairs while ensuring the quality and performance of the cladding layer.

[0021] Furthermore, argon atmosphere protection can prevent the entry of oxygen during the cladding process and avoid oxidation of the cladding layer, thereby improving the quality of the cladding layer and avoiding the generation of pores. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the turbine blades and sealing teeth of the existing aircraft engine of the present invention; Figure 2 It is a schematic diagram of the blade shroud joint surface on both sides of the existing aircraft engine turbine blade of the present invention; Figure 3 This is a flow chart of a method for repairing a turbine blade crown of an aero-engine according to the present invention; Figure 4 It is a schematic diagram of the joint surface between the back side of the blade and the blade basin side before cladding repair according to the present invention; Figure 5 It is a schematic diagram of removing the sealing teeth before cladding repair according to the present invention; Figure 6 It is a schematic diagram of the joint surface between the back side of the blade crown and the blade basin side of the cladding and stacking method of the present invention; Figure 7 It is a schematic diagram of the side of the cladding stacking sealing teeth and the blade crown intake of the present invention; Figure 8 This is a schematic diagram of grinding after laser cladding repair according to the present invention; In the figure, 1- blade crown sealing tooth, 2- blade crown joint surface, 3- blade basin side blade crown joint surface, 4- blade back side blade crown joint surface, 5- blade back side, 6- blade basin side, 7- grinding sealing tooth, 8- sealing plate, 9- blade back side blade crown joint surface stacking, 10- blade basin side blade crown joint surface stacking, 11- sealing tooth stacking, 12- blade crown intake side stacking, 13- forming grinding wheel. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] like Figure 1 As shown, the present invention provides an aircraft engine turbine blade crown repair material, including nickel-based high-temperature alloy powder, the mass percentage of which is as follows: Cr: 18.0~21.0%; Co: 15.0~21.0%; Al: 1.0~2.0%; Ti: 2.0~3.0%; Fe≤1.5%; Si≤0.8%; Mn≤0.4%; Cu≤0.2%; Zr≤0.15%; C≤0.13%; S≤0.015%; P≤0.015%; B≤0.02%; the balance is Ni.

[0028] The nickel-based high-temperature alloy powder has a particle size of -80 to +320 meshes. Before laser cladding, the alloy powder is vacuum dried at 120°C to remove moisture.

[0029] The selected cladding powder material has similar performance to the blade raw material GH105. The melting temperatures of the two are similar, namely: blade material 1340-1380℃, powder material 1400℃; the density is relatively close, 7.97g / cm3 and 8.20g / cm3 respectively. The selected powder material has low AI and Ti content, good material welding performance, and is not prone to defects such as cracks.

[0030] The present invention also provides a method for repairing a turbine blade shroud of an aero-engine, comprising: S101 grinding to remove wear and crack defects of sealing teeth of parts; S102 Grind the blade crown joint surface 2 and the intake side surface of the parts; S103 performs heat treatment on the parts; S104 Clean the sealing teeth 1, blade crown joint surface 2 and intake side of the parts after grinding; S105 uses repair materials to perform laser cladding repair on the sealing teeth 1, the blade crown joint surface 2 and the intake side; S106 Secondary grinding of the blade crown joint surface 2 and the intake side surface; S107 grinding parts leaf crown sealing teeth 1; S108 performs clamp repair and vacuum aging treatment on parts.

[0031] Grinding and removing the wear and crack defects of the sealing teeth of parts are as follows: Grind the blade parts to remove the worn and cracked parts on the upper part of the sealing teeth, keep the root height 0.2 to 0.5 mm from the top surface of the sealing plate, and perform fluorescence detection until the fluorescence detection is qualified.

[0032] This step ensures accurate repair of the seal teeth and avoids loss of sealing performance due to wear or cracks. Fluorescence testing ensures the quality of the repair and ensures that no cracks or defects are missed.

[0033] Grind the blade crown joint surface and the air intake side: Remove the worn surfaces of the blade back and blade basin joint surfaces and the intake side to 0.5 mm below the final size. This step ensures the precise repair of the blade crown joint surface and the intake side, grinds off the original worn surface, and prepares for cladding repair.

[0034] The heat treatment of the parts is specifically as follows: vacuum annealing the parts, the vacuum annealing temperature is 1020-1040°C, and the insulation time is 10-12min.

[0035] Vacuum annealing can eliminate the internal stress of parts generated during the processing, improve the microstructure of the material, and reduce the deformation and cracks generated during the cladding process.

[0036] The parts after cleaning and grinding are as follows: Sandblasting is used to remove the oxide layer on the sealing teeth, blade crown joint surface 2 and intake side surface of the parts, and acetone is used to scrub the surface to be clad to clean the parts.

[0037] The surface cleanliness before laser cladding is ensured, the oxide layer and impurities that may affect the cladding quality are removed, and the bonding strength and overall quality of the cladding layer are improved.

[0038] Laser cladding repairs are performed using a 1000w fiber laser.

[0039] Using high-power fiber lasers for laser cladding can achieve fast and precise repairs while ensuring the quality and performance of the cladding layer.

[0040] The laser cladding process was protected by argon atmosphere.

[0041] Argon atmosphere protection can prevent the entry of oxygen during the cladding process and avoid oxidation of the cladding layer, thereby improving the quality of the cladding layer and avoiding the generation of pores.

[0042] The secondary grinding of the blade crown joint surface 2 and the intake side surface is specifically as follows:

[0043] First, grind the cladding material accumulated on both ends of the exhaust side of the blade crown due to the welding of the blade basin and the blade crown joint surfaces 2 on both sides of the blade back, then fine-grind the intake side of the blade crown based on the exhaust side edge plate surface, and finally fine-grind the blade basin side and blade back side blade crown joint surfaces 4.

[0044] It ensures the precise repair and coordination of each surface of the blade crown, avoids dimensional deviation and surface unevenness caused by accumulation of cladding material, and improves the overall performance of the blade.

[0045] The vacuum aging temperature is 695-705℃, and the holding time is 960-980min.

[0046] Vacuum aging treatment can further eliminate the internal stress generated during laser cladding and grinding, and improve the stability and service life of the material. At the same time, the insulation time at high temperature also helps to improve the microstructure and performance of the material.

[0047] The detailed steps are: 1) Grinding to remove wear and crack defects on the sealing teeth The repaired blade is ground to remove the worn parts and cracked parts on the upper part of the sealing teeth as a whole until the fluorescence detection is qualified. The grinding method of the present invention adopts the method of grinding down the sealing teeth as a whole to remove the cracks, wear and other damages of the crown sealing teeth 1 to the maximum extent, and retains the root height of 0.2 to 0.5 mm from the top surface of the sealing plate, so as to facilitate the laser cladding stacking. Figure 5 For blades with cracks less than 0.2 mm in height and still unable to be removed, no further repairs will be performed.

[0048] 2) Grind the blade crown joint surface 2 and the air intake side Grind the back side of the blade crown, the blade crown joint surface 3 on the blade basin side and the air inlet side of the blade crown, such as Figure 2 and Figure 4 , to 0.5mm below the final size, remove the worn surface and prepare for cladding.

[0049] 3) Surface annealing In order to reduce the possibility of cracks during laser repair, the parts were heat treated by vacuum annealing at 1030°C for 10 min.

[0050] 4) Clean the cladding surface Sandblasting is used to remove the oxide layer on the sealing teeth, blade crown joint surface and intake side of the surface to be clad, and acetone is used to scrub the surface to be clad to clean the parts.

[0051] 5) Laser cladding repair The coaxial powder feeding laser cladding equipment is used for repair, and the nickel-based high-temperature alloy powder is directly fed into the high-temperature molten pool area scanned by the laser, and deposited layer by layer. The laser cladding process is protected by argon atmosphere.

[0052] The laser cladding equipment uses a 1000W fiber laser, and the repair parameters are: laser cladding power 300W, scanning speed 280mm / min, spot size φ1mm, powder feeding rate 6g / min, layer height 0.2mm.

[0053] According to the different removal amounts of each part before repair, the thickness of the blade basin side, the blade back side, the blade crown joint surface 3, 4 and the blade crown intake side is stacked up by 1mm, and the sealing teeth are stacked up by 2mm in width and 3mm in height. Figure 6 and Figure 7 shown.

[0054] 6) Grind the blade crown joint surface 2 and the air intake side After the parts are laser clad, restore the size of the blade crown edge plate positioning surface. First, grind the cladding material accumulated on both ends of the blade crown exhaust side due to the cladding of the blade basin and the blade crown joint surface on both sides of the blade back to ensure the end is flat. Then, fine-grind the blade crown intake side based on the exhaust side edge plate surface. The third step is to fine-grind the blade crown joint surface 3 on the blade basin side and the blade crown joint surface 4 on the blade back side.

[0055] 7) Forming grinding crown sealing teeth 1 Grinding of the crown sealing teeth 1. Use the profile grinding wheel to grind the sealing tooth profile in one step. Figure 8 8) Pliers repair Use pliers to trim excess cladding material and various joints, and manually grind each joint mark to make it smooth.

[0056] 9) Vacuum aging Vacuum aging at 700℃ and heat preservation for 16 hours to restore blade performance.

[0057] 1. This method can repair two types of fault modes, namely, wear and crack of blade crown sealing teeth 1 and wear of blade crown joint surface at one time. It integrates the repair method of argon arc welding that only repairs one defect at a time, broadens the repairable range of blades, and improves the repair quality and efficiency.

[0058] 2. Give full play to the advantages of laser cladding repair, such as high energy density, small heat input, good repair accuracy, the quality of repair is not dependent on the welder's operation technology, good repair consistency, and small processing allowance. It solves the problems of argon arc welding repair burning through the top surface of the sealing plate and the failure to fill the root of the sealing tooth during cladding, resulting in the step after repair, as well as blade deformation and welding cracks.

[0059] 3. The room temperature tensile strength and high temperature tensile strength of the sample after laser cladding repair reached more than 80% of the substrate.

[0060] 4. During the repair process, the blade crown sealing teeth 1 and the blade crown joint surface are piled up to compensate for the deformation and size changes during the use of the blade. During the repair process, the exhaust side of the blade crown is kept unpiled, which is used as a reference to reduce the difficulty of repair caused by re-determining the reference and coordinating the reference back and forth on the repaired surface.

[0061] 5. The repaired sealing teeth are processed by forming grinding wheels to complete the dimensions of the three sealing teeth inlet and exhaust surfaces at one time. Compared with processing each surface separately, the dimensional consistency is good, the qualified rate is high, and the efficiency is improved.

[0062] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. An aircraft engine turbine blade shroud repair material, characterized in that: It includes nickel-based high-temperature alloy powder, and its components by mass percentage are as follows: Cr：18.0～21.0%； Co: 15.0~21.0%; Al: 1.0~2.0%; Ti: 2.0~3.0%; Fe≤1.5%; Si≤0.8%; Mn≤0.4%; Cu≤0.2%; Zr≤0.15%; C≤0.13%; S≤0.015%; P≤0.015%; B≤0.02%; the balance is Ni.

2. A method for repairing a turbine blade shroud of an aircraft engine, characterized in that: include: Grinding to remove wear and crack defects on the sealing teeth of parts; Grind the blade crown joint surface (2) and the air intake side surface of the part; Annealing heat treatment of parts; Clean the sealing teeth (1), the blade crown joint surface (2) and the air intake side of the parts after grinding; Using a repair material to perform laser cladding repair on the blade crown sealing teeth (1), the joint surface (2) and the air intake side surface; Milling and grinding the blade crown joint surface (2) and the air intake side surface; Grinding parts: leaf crown sealing teeth (1); The parts are clamped and vacuum aged.

3. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: Grinding and removing the wear and crack defects of the sealing teeth of parts are as follows: Grind the blade parts to remove the worn and cracked parts on the upper part of the sealing teeth, keep the root height 0.2 to 0.5 mm from the top surface of the sealing plate, and perform fluorescence detection until the fluorescence detection is qualified.

4. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: The specific steps for grinding the blade crown joint surface and the air intake side are as follows: The worn surfaces of the blade back side, blade basin side joint surface and intake side are removed to a final size of 0.5 mm.

5. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: The heat treatment of the parts is specifically as follows: vacuum annealing of the parts, the vacuum annealing temperature is 1020-1040°C, and the insulation time is 10-12min.

6. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: Clean the sealing teeth (1), the blade crown joint surface (2) and the air intake side of the parts in the following steps: The oxide layer on the sealing teeth (1), the blade crown joint surface (2) and the intake side surface of the parts is removed by sandblasting, and the surface to be clad is scrubbed with acetone to clean the parts.

7. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: Laser cladding uses a 1000w fiber laser for repair, and the laser cladding process is protected by argon atmosphere.

8. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: The secondary grinding of the blade crown joint surface (2) and the air intake side surface is specifically as follows: first, the cladding material accumulated on the blade crown joint surfaces on both sides of the blade back due to the cladding of the blade basin at both ends of the blade crown exhaust side surface is ground; then, the blade crown intake side surface is finely ground with the exhaust side edge plate surface as a reference; and finally, the blade crown joint surface (3) on the blade basin side and the blade crown joint surface (4) on the blade back side are finely ground.

9. The method for repairing a turbine blade shroud of an aircraft engine according to claim 2, characterized in that: The clad sealing teeth are ground with a forming grinding wheel to achieve the designed size.

10. The method for repairing a shroud of a turbine blade of an aircraft engine according to claim 2, characterized in that: The vacuum aging temperature is 695-705℃, and the holding time is 960-980min.

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