Method for repairing blade damping table through combination of argon arc welding and supersonic spraying

Abstract

The invention discloses a method for repairing a blade damping table through combination of argon arc welding and supersonic spraying, and belongs to the technical field of aviation part repairing. The method comprises the following steps: firstly, repairing cracks of the damping table through argon arc welding, and ensuring the welding quality through nondestructive testing and stress relief heat treatment; then, the welding repair area is ground down; spraying a high-cobalt-molybdenum-chromium wear-resistant coating with specific components on the end surface by adopting a high velocity oxy-fuel spraying technology; and finally, the design size is recovered through accurate grinding. The coating prepared through high velocity oxy-fuel spraying has the outstanding advantages of high density, high hardness and high bonding strength, the crack defect is thoroughly eliminated, the size is recovered, the abrasion resistance and corrosion resistance of the blade damping table are remarkably improved, the service life of the blade is prolonged, economic benefits are remarkable, and the application prospect is wide. And the method is suitable for remanufacturing high-value precision parts such as aero-engines.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal spraying and aviation component repair, and particularly relates to a method for repairing a blade damping platform by combining argon arc welding and supersonic spraying. BACKGROUND

[0002] Fan or compressor blades of an aero-engine or a gas turbine are usually provided with damping platforms (also referred to as shock-absorbing bosses) for reducing vibration during operation of the blades. During high-speed operation, the damping platforms of the blades rub against each other, and are prone to damage such as wear, cracks and chipping. If the damaged blades are used continuously, the cracks will continue to expand, and problems such as chipping may occur, which affects flight safety. The damaged blades usually need to be replaced as a whole, resulting in high economic losses.

[0003] Currently, for the damping platforms of the blades with cracks, argon arc welding is usually used for repair. However, welding repair will cause welding shrinkage and unevenness on the end face, resulting in size out-of-tolerance. In order to restore the size, the existing technology usually adopts a thermal spraying process, such as spraying a tungsten carbide wear-resistant material, but the coating of such a material is prone to micro-cracks, and has poor corrosion resistance, which is difficult to meet the requirements of high reliability, long service life and corrosion resistance of the blades of aviation components.

[0004] In addition, in the prior art, there is also a brazing method for preparing a wear-resistant layer on the surface of the damping platform to play a shock-absorbing role, but this kind of welding repair method mainly has two technical difficulties: first, the weld position needs to be polished smooth after welding repair, and if there is a step difference, it will seriously affect the adhesion of the subsequent coating; second, the surface after welding repair needs to select appropriate sandblasting process parameters, and if the selection is improper, it is easy to cause pollution at the coating interface, affecting the quality of the coating.

[0005] Therefore, there is an urgent need for a composite repair process that can comprehensively solve the problems of crack repair, size restoration and performance improvement. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art, and provides a method for repairing a blade damping platform by combining argon arc welding and supersonic spraying. The method repairs cracks by argon arc welding, and sprays a high-performance wear-resistant and corrosion-resistant coating by combining supersonic flame spraying technology, and finally restores the size by fine grinding, thereby realizing comprehensive repair of the blade damping platform, and making the wear resistance and corrosion resistance of the blade damping platform better than the original state while restoring the size.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: The present application provides a method for repairing a blade damping platform by combining argon arc welding and supersonic spraying, comprising the following steps: S1: repairing cracks on the blade damping platform by using an argon arc welding process; S2: grinding the end face of the damping platform after step S1 to make the surface flush; S3: supersonic flame spraying on the end face of the damping platform after step S2 to form a wear-resistant coating; S4: grinding the coating formed in step S3 to the design size of the damping platform of the blade.

[0008] In one embodiment, the step S1 comprises: determining the position of the crack defect on the damping platform of the blade by fluorescent penetration inspection; mechanically polishing to remove the crack until the defect is completely eliminated and ensuring smooth transition of the polishing position to the periphery; using a welding wire matched with the blade material for argon arc welding repair, and using argon as the protective gas during welding; carrying out non-destructive testing on the weld, which includes visual inspection, fluorescent penetration inspection and X-ray detection; carrying out vacuum stress relief heat treatment on the weld that passes the detection; carrying out fluorescent penetration inspection on the weld again after heat treatment.

[0009] In one embodiment, the vacuum stress relief heat treatment is carried out at a temperature of 600℃±10℃ and for 2h.

[0010] In one embodiment, the step S3 comprises: cleaning the end face to be sprayed with an organic solvent; masking the non-spraying area with high-temperature resistant protective tape and high-temperature resistant silicone sealant; blasting the cleaned and masked end face with corundum sand; spraying the wear-resistant coating on the blasted end face with a supersonic flame spraying device, and the thickness of the coating is ≥0.5mm.

[0011] In one embodiment, the spraying material used in the supersonic flame spraying is Co 28.5 Mo 17.5 Cr 3.4 Si alloy powder.

[0012] In one embodiment, 20-60 mesh white corundum sand is used for sandblasting.

[0013] In one embodiment, in the step S4, a special grinding clamp matched with the blade is used to fix the blade, and a green silicon carbide grinding wheel is used to grind the coating on a surface grinding machine to make the coating reach the design size of the damping platform of the blade.

[0014] In one embodiment, the ground coating surface and transition area are subjected to fluorescent penetrant inspection to ensure no cracks.

[0015] In one embodiment, the repaired coating has a hardness of no less than 89HR15N and a bonding strength of no less than 53MPa.

[0016] In one embodiment, the method further comprises step S5: sampling the repaired blade damping platform and performing microscopic structure detection on the wear-resistant coating to confirm that the structure is uniform and that the bonding interface between the coating and the underlying argon arc welding repair layer has no cracks or delamination.

[0017] Compared with the prior art, the present application has the following advantages: 1. The combination of argon arc welding and non-destructive testing ensures the fundamental quality of crack repair; the spraying and grinding processes effectively restore the size, and the final product is ensured to be defect-free through fluorescent inspection, with high repair reliability.

[0018] 2. The high cobalt-molybdenum high chromium (Co 28.5 Mo 17.5 Cr 3.4 Si) coating with specific components is sprayed using the supersonic flame spraying technology. The supersonic flame spraying process can produce a particle speed of up to 750m / s, forming a dense, low-oxide content, high bonding strength coating. The coating not only restores the size, but also endows the damping platform with wear resistance and corrosion resistance due to its high hardness and high bonding strength, significantly prolonging the service life of the blade.

[0019] 3. The method allows the damaged and scrapped expensive blade to be reused, avoiding the replacement of the entire piece and saving costs, and is particularly suitable for the remanufacturing of high-value components such as aircraft engines, with great economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The flowchart of the method for repairing the blade damping platform by combining argon arc welding and supersonic spraying according to an embodiment of the present application.

[0021] Figure 2 The structural schematic diagram of the blade damping platform according to an embodiment of the present application.

[0022] Figure 3 The supersonic flame spraying process according to an embodiment of the present application; wherein (a) is a shielding schematic diagram, and (b) is a spraying schematic diagram.

[0023] Figure 4 The appearance schematic diagram of the repaired blade damping platform according to an embodiment of the present application.

[0024] Figure 5 The microscopic structure picture of the repaired area according to an embodiment of the present application. Detailed Implementation

[0025] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0026] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] This invention provides a method for repairing blade damping platforms using a combination of argon arc welding and supersonic spraying, such as... Figure 1 As shown, it includes the following steps: S1. Repairing blade damping platform cracks using argon arc welding process. Specifically, the blade to be repaired is first subjected to fluorescence penetrant testing to determine the exact location and morphology of the damping platform crack defect. The structure of the blade damping platform is as follows: Figure 2 As shown. Under the guidance of ultraviolet light, the cracks and defects in the damping platform are mechanically ground until they are completely removed, ensuring a smooth transition between the ground area and the surrounding area without burrs. After grinding, the ground area is repaired by argon arc welding using welding wire matching the blade material. Preferably, the welding wire is made of the same material as the blade. During welding, an auxiliary shielding gas is used to prevent the blade from oxidizing during welding. Preferably, argon is used as the auxiliary shielding gas. After welding, the weld is subjected to non-destructive testing, such as visual inspection, fluorescent penetrant testing, and X-ray testing, to ensure that there are no defects such as cracks or porosity. If cracks are found, the defects are ground again and repaired by welding. Because welding is a process of localized rapid heating and cooling, uneven thermal expansion and contraction leads to the generation of residual stress. Therefore, stress-relieving heat treatment is required for welds that pass the inspection. For example, the stress-relieving heat treatment is vacuum heat treatment, with process parameters of heating to 600℃±10℃ and holding for 2 hours. Through stress-relieving heat treatment, the stress is redistributed and significantly reduced, thereby improving the overall performance, reliability, and service life of the welded parts. After heat treatment, the weld area is subjected to fluorescent penetrant testing again to check for cracks on the surface. If cracks are found, they are mechanically ground until they are completely eliminated. After grinding, the ground area is made to ensure a smooth transition with the surrounding area without burrs. Finally, it is confirmed that there are no cracks.

[0028] S2. Grind the blade damping platform end face until flush with the surface. Specifically, after the argon arc welding repair of the blade damping platform crack, the end face is uneven due to the weld, which will reduce the adhesion of the coating on the surface of the part, so the blade damping platform needs to be ground. The end face of the damping platform repaired in step S1 is ground to eliminate the protrusions, steps and unevenness caused by welding, restore the flatness of the end face, and measure and record the current damping platform size; This step solves the problem of the influence of the step difference of the welding repair surface on the coating adhesion, providing an excellent substrate for subsequent spraying.

[0029] S3, ultrasonic flame spraying on the end face of the blade damping platform Specifically, the end face to be sprayed is thoroughly cleaned with an organic solvent. For example, the end face of the blade damping platform is wiped with an organic solvent to remove contaminants on the end face. Supersonic flame spraying is a process in which fuel (such as acetylene, hydrogen, etc.) is mixed with oxygen in a combustion chamber and ignited, and a high-temperature high-speed combustion flame is generated through a Laval nozzle. Powder particles are heated to a molten or semi-molten state in the high-speed flame and accelerated to extremely high speed (750 m / s) to deposit on the substrate surface to form a dense coating. Due to the high temperature and high impact force of supersonic flame spraying, it is difficult to shield and protect, so a shielding method combining high-temperature protective tape and high-temperature silicone putty is designed to shield the non-sprayed area adjacent to the sprayed area, as shown in Figure 3 (a), that is, a composite shielding method using high-temperature protective tape and high-temperature silicone putty is used to protect the non-sprayed area adjacent to the sprayed area. The cleaned and shielded end face is subjected to corundum sand blasting and roughening treatment, preferably, the corundum sand is white corundum sand with a particle size range of 20 to 60 mesh. The sand blasting process parameters are optimized to effectively clean and roughen the substrate surface, increase the surface area, and improve the mechanical bonding strength of the coating and the substrate, while avoiding the risk of interface contamination. As shown in Figure 3 (b), after sand blasting, the end face is sprayed with a high cobalt-molybdenum-high-chromium wear-resistant coating using a supersonic flame spraying device, and the coating thickness is not less than 0.5 mm; after spraying, the appearance, thickness, metallography, hardness and bonding strength of the coating are checked; for example, the sprayed material of supersonic flame spraying is high cobalt-molybdenum-high-chromium alloy powder, and the composition is Co 28.5 Mo 17.5 Cr 3.4 SiI, the coating formed by the cobalt-based alloy powder with this specific composition after supersonic flame spraying has extremely high hardness and excellent bonding strength, with a hardness of more than 89 HR15N and a bonding strength of more than 53 MPa. The high molybdenum and high chromium content together endow the coating with excellent wear resistance and corrosion resistance.

[0030] S4, grinding the coating to the design size of the blade damping platform Specifically, the blade is fixed by using a special grinding fixture matched with the blade, which is used to reliably clamp and protect the blade during grinding to prevent deformation or damage during processing. A plane grinder and a green silicon carbide grinding wheel are used for precision grinding of the sprayed coating, so that the size accuracy and surface roughness of the blade damper table meet the design requirements of the blade damper table, so that the blade damper table is restored to the state required by the design. For example, the type of the plane grinder can be selected as M7130. The coating surface and the transition zone after grinding are subjected to fluorescent penetration inspection to ensure that there is no crack, thereby completing the repair of the blade damper table.

[0031] S5, microscopic structure detection The repaired blade damper table is sampled, and the microscopic structure of the wear-resistant coating is detected to confirm that the structure is uniform, and there is no crack and delamination phenomenon between the coating and the lower argon arc welding repair layer. This step verifies the repair quality of the method and ensures the reliability of the repair effect and the integrity of the internal quality.

[0032] The blade in the method described in the embodiment of the application is a fan or compressor blade of an aero-engine or a gas turbine, and the blade material is titanium alloy or high-temperature alloy.

[0033] A specific embodiment is provided below to illustrate the above method.

[0034] Specifically, the titanium alloy fan blade damper table is repaired by using the above method.

[0035] The blade is an aero-engine fan blade, the material is TC6 titanium alloy, and the damper table end face has serious wear and multiple cracks.

[0036] The damper table is repaired by using the above method, which mainly includes the following steps: Fluorescent inspection and pretreatment: the blade damper table is subjected to fluorescent penetration inspection, and all crack positions on the damper table end face are clearly displayed and marked. Under the guidance of a purple light lamp, all cracks are mechanically polished and removed to ensure that the defects are completely excluded and form a smooth transition groove with the base body.

[0037] Argon arc welding repair: TC6 titanium alloy welding wire is used to repair the polished area under the protection of high-purity argon. The protection of argon effectively prevents the oxidation of titanium alloy at high temperature, ensuring the purity of the weld.

[0038] Post-weld inspection and heat treatment: After welding repair, the weld quality is confirmed to be qualified without cracks and incomplete fusion defects through visual, fluorescent and X-ray inspection. Then the blade is placed in a vacuum heat treatment furnace for vacuum stress relief heat treatment at 600℃±10℃ for 2 hours. This heat treatment process can effectively eliminate welding residual stress, redistribute stress, and significantly improve the overall performance and fatigue life of the welded joint. After furnace cooling, fluorescent inspection is performed again, and no cracks are found.

[0039] Grinding treatment: The end face of the damping platform after heat treatment is ground to be flush, and the end face size is measured. This operation completely eliminates the weld reinforcement and step difference caused by welding, makes the whole flat, solves the problem of coating adhesion reduction caused by uneven traditional welding repair surface, and measures and records the size as the spraying reference.

[0040] Spraying preparation and implementation: The end face is thoroughly cleaned with acetone to remove oil stains. High-temperature resistant adhesive tape and silicone are used to accurately mask the non-spraying area. Then the end face is sandblasted with 20-mesh white corundum sand. This optimized sandblasting process effectively avoids interface pollution while cleaning the surface and forming the necessary roughness. The spraying area is sprayed with Co 28.5 Mo 17.5 Cr 3.4 Si alloy powder to form a coating layer with a thickness of 0.55mm.

[0041] Finishing and final inspection: The fan blade is fixed using a special grinding clamp, and the coating is precisely ground to the design size using a surface grinding machine (such as M7130) and green silicon carbide grinding wheel. The size measurement meets the requirements, and the appearance after grinding is shown in Figure 4 . Finally, the end face of the repaired area of the blade damping platform and the transition area around the end face are inspected by fluorescent and X-ray, and no cracks are found. The blade damping platform repair is completed, and the repaired blade damping platform is smooth and flat in appearance, and the size meets the assembly requirements.

[0042] Performance and microstructure verification: A piece of blade damping platform argon arc welding repair part wear-resistant coating sample is randomly selected for detection. The detection results show that the coating hardness reaches 89HR15N, and the bonding strength reaches 53MPa. Under a microscope, the microstructure of the repaired area is shown in Figure 5 . The microstructure of the high-velocity oxy-fuel sprayed wear-resistant coating is uniform and dense; the bonding interface between the wear-resistant coating and the underlying argon arc welding repair layer presents a good bonding state without incomplete fusion, cracks and delamination. At the same time, it can also be observed that the bonding interface between the argon arc welding repair layer and the blade substrate is also intact without defects. The microstructure detection results fully verify the excellent internal quality and reliability that can be achieved by the method of the present application, especially the integrity of the bonding between the wear-resistant coating as a functional layer and the substrate.

[0043] The above description is merely that of the preferred embodiments of the application, and is not intended to limit the application. One skilled in the art can readily devise variations and modifications without departing from the scope of the present application as defined by the following claims. Accordingly, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. A method for repairing a blade damper platform by combining argon arc welding and high velocity oxy-fuel spraying, characterized in that, Includes the following steps: S1: The crack on the blade damping platform was repaired using argon arc welding. S2: Grind the end face of the damping table after step S1 to make its surface flush. S3: Apply supersonic flame spraying to the damping platform end face after step S2 to form a wear-resistant coating. S4: Grind the coating formed in step S3 to achieve the design dimensions of the blade damping platform.

2. The method of claim 1, wherein, Step S1 includes: The location of cracks on the blade damping platform was determined by fluorescent penetrant testing. Mechanical grinding removes the cracks until the defect is completely eliminated, ensuring a smooth transition between the grinding area and the surrounding area; Argon arc welding was performed using welding wire that matched the blade material, with argon gas used as a shielding gas during the welding process. Non-destructive testing is performed on the weld, including visual inspection, fluorescent penetrant testing, and X-ray inspection. Vacuum stress-relieving heat treatment is performed on welds that pass inspection; After heat treatment, the weld was subjected to fluorescent penetrant testing again.

3. The method of claim 2, wherein, The vacuum stress-relieving heat treatment was carried out at a temperature of 600℃±10℃ and held for 2 hours.

4. The method according to claim 1, characterized in that, Step S3 includes: Clean the surface to be coated with an organic solvent; High-temperature resistant protective tape and high-temperature resistant silicone putty are used to mask non-sprayed areas; The cleaned and masked end face is then treated with corundum sand blowing. The wear-resistant coating is applied to the sandblasted end face using a supersonic flame spraying device, and the coating thickness is ≥0.5mm.

5. The method according to claim 4, characterized in that, The spray material used in the supersonic flame spraying is Co 28.5 Mo 17.5 Cr 3.4 Si alloy powder.

6. The method according to claim 4, characterized in that, Sandblasting treatment was performed using 20-60 mesh white corundum sand.

7. The method according to claim 1, characterized in that, In step S4, the blade is fixed using a special grinding fixture that matches the blade, and the coating is ground using a surface grinder and a green silicon carbide grinding wheel to make the coating reach the design dimensions of the blade damping platform.

8. The method according to claim 7, characterized in that, Fluorescent penetrant testing was performed on the surface of the coating and the transition area after grinding to ensure that there were no cracks.

9. The method according to claim 1, characterized in that, The hardness of the coating repaired by the method is not less than 89HR15N, and the bonding strength is not less than 53MPa.

10. The method according to any one of claims 1 to 9, characterized in that, The method also includes step S5: taking a sample of the repaired blade damping platform, performing microstructure testing on the wear-resistant coating to confirm that its structure is uniform and that there are no cracks or delamination at the interface between the coating and the underlying argon arc welded repair layer.

Images