A method of repairing a thin-walled spherical joint of an irregularly shaped conduit

Abstract

The application discloses a kind of thin-walled spherical joint near net forming repair methods of irregular shape conduit, it is related to the repair method of part damage, comprising the following steps: S1, using clamp repair machinery to remove the metal sealing coating of spherical pipe joint on air leakage pipe;S2, the pipe mouth of air leakage pipe is blocked;S3, using sand blasting equipment to sand blast air leakage pipe;S4, air leakage pipe after sand blasting is roughened and clamped on positioning tool;S5, air leakage pipe positioning tool is clamped with air leakage pipe and installed in spraying equipment, and metal sealing coating is sprayed outside air leakage pipe;S6, air leakage pipe is taken off from positioning tool, and the performance of air leakage pipe is detected.The application can not only ensure that spherical pipe joint on air leakage pipe is zero damage and zero deformation, but also effectively ensure that the spherical center of spherical pipe joint on air leakage pipe coincides with the rotation center of equipment during sand blasting and spraying, to ensure the precision of sand blasting and spraying.

Description

Technical Field

[0001] This invention relates to a method for repairing damaged parts, and more specifically, to a method for near-net-shape repair of a thin-walled spherical connector for an irregularly shaped conduit. Background Technology

[0002] The air leak pipe is an external pipeline of the high-pressure pneumatic system of an aero-engine. Its main function is to vent excess air from the compressor to the power turbine. The working medium is high-pressure air. Its end is usually equipped with a spherical fitting to form a swingable, self-sealing spherical connection with adjacent pipelines or equipment. The surface of the fitting is coated with a metallic sealing coating, primarily for sealing, resisting fretting wear, and extending the fitting's service life. However, during engine operation, this fitting may come into contact with and be squeezed against the engine casing piping, causing damage and peeling of the coating. In severe cases, this can affect the engine's operating power.

[0003] For thin-walled spherical fittings for irregularly shaped conduits, the following problems exist with commonly used repair techniques due to the extremely thin wall thickness (approximately 1 mm), complex conduit shape, poor overall rigidity, and susceptibility to deformation: (1) Removal process: When the old coating is removed by sandblasting, the impact force will cause plastic deformation of the thin-walled spherical pipe joint; chemical removal will easily corrode the substrate; and the pipe itself is irregular in shape and cannot be stably clamped and machined on a regular lathe. Forced clamping may also cause the pipe to deform as a whole.

[0004] (2) Spraying process: After conventional spraying, the surface is prone to roughness or dimensional deviation, requiring turning or grinding post-processing; however, for thin-walled spherical pipe joints, the cutting force of post-processing can easily cause part deformation and coating collapse, resulting in a very low yield. Furthermore, due to the irregular shape of the conduit, it is difficult to achieve precise positioning on general equipment. During the spraying process, molten powder can easily enter the interior of the slender and curved pipe, forming excess material. Summary of the Invention

[0005] The purpose of this invention is to provide a near-net-shape repair method for thin-walled spherical connectors of irregularly shaped conduits, in order to solve the above-mentioned problems.

[0006] To achieve the objective of this invention, the technical solution adopted is as follows: a method for near-net-shape repair of thin-walled spherical connectors for irregularly shaped conduits, comprising the following steps: S1. Use a pliers to repair and remove the metal sealing coating on the spherical pipe joint of the air leak pipe; S2. Seal the opening of the air leak pipe and protect the parts of the air leak pipe that do not need repair with masking tape; S3. Place the air leak pipe that has completed step S2 into a sandblasting device for sandblasting roughening. S4. Remove the air leak pipe that has completed step S3 from the sandblasting equipment and clamp it onto the positioning fixture. S5. Install the positioning fixture with the air leakage pipe in the plasma spraying equipment, and spray a metal sealing coating on the outside of the air leakage pipe through the plasma spraying equipment. S6. Remove the air leak pipe from the positioning fixture and clean the air leak pipe opening. Check the air leak pipe for leaks.

[0007] Furthermore, in step S2, the material used to seal the opening of the air leak pipe is high-temperature resistant putty.

[0008] Furthermore, the positioning fixture in step S3 includes a circular base with bushings on the upper and lower surfaces, and a connecting component and a support plate are also installed on the circular base. The connecting component is used to clamp the conduit of the air leakage pipe, and a clamping positioning structure is also installed on the top of the support plate. A detachable protective cover for the fixture component is installed on the clamping positioning structure.

[0009] Furthermore, in step S4, when the sandblasting equipment roughens the air leakage pipe, the abrasive is white corundum or brown corundum, the diameter of the sandblasting nozzle is 10-15mm, the sandblasting pressure is 0.20-0.40MPa, the sandblasting angle is 15°-45°, and the sandblasting distance is 100-250mm.

[0010] Furthermore, in step S5, the metal sealing coating is a copper-nickel-indium coating, and the spraying method is plasma spraying; during the spraying process, the argon flow rate is 30-50 NL / min, the nitrogen flow rate is 2-6 NL / min, the current is 400-500 A, the voltage is 40-60 V, the powder feeding speed is 3-8 rpm, the spraying distance is 100-200 mm, and the spraying angle is 45-90°.

[0011] Furthermore, in step S6, the air leak pipe is checked for sealing using kerosene as the medium, at a pressure of 5–10 MPa, and for a pressure holding time of 10–15 minutes.

[0012] The beneficial effects of this invention are: In this invention, the metal sealing coating of the spherical pipe joint on the air leak pipe is first repaired and removed by a clamping machine. Then, it is clamped on a positioning fixture and sandblasted. This not only ensures zero damage and zero deformation of the spherical pipe joint on the air leak pipe, but also ensures that the center of the spherical pipe joint on the air leak pipe coincides with the rotation center of the equipment during the sandblasting and coating process. This ensures uniform sandblasting and coating, and guarantees the accuracy of sandblasting and coating.

[0013] By sealing the opening of the air leak pipe, it is effective to prevent particles from the subsequent sandblasting process and paint from the spraying process from entering the air leak pipe. Attached Figure Description

[0014] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0015] Figure 1 This is a structural diagram of the positioning fixture; Figure 2 This is a structural diagram of an air leak pipe clamped onto a positioning fixture; Figure 3 These are comparison photos of the spherical pipe joint surface on the air leak pipe before and after repair.

[0016] The attached diagram shows the markings and corresponding component names: 1. Disc base, 2. Bushing, 3. Connecting component, 4. Support plate, 5. Clamping and positioning structure, 6. Tooling component protective cover. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] This invention provides a near-net-shape repair method for thin-walled spherical connectors of irregularly shaped conduits, comprising the following steps: S1. Mechanical Grinding and Repair: The fitter uses a grinding wheel or polishing machine to precisely repair and remove the failed metal sealing coating on the surface of the spherical pipe joint on the air leak pipe, so that the spherical pipe joint on the air leak pipe is exposed to a metallic luster. The fitter then visually inspects and confirms that the metal sealing coating on the surface of the spherical pipe joint on the air leak pipe has been completely removed. S2. High-temperature resistant putty sealing: Use thermal spray putty to seal the opening of the air leak pipe. The thermal spray putty is selected from phosphate corundum putty, phosphate high alumina putty or water glass high-temperature resistant putty to prevent particles in the subsequent sandblasting process and paint in the spraying process from entering the air leak pipe. At the same time, use masking tape to protect the parts of the air leak pipe that do not need to be repaired. S3. Clamping: The air leak pipe completed in steps S1 and S2 is fed into the sandblasting equipment, and white or brown fused alumina is used as the abrasive. A sandblasting nozzle with a diameter of 10-15mm is selected. The sandblasting equipment performs light sandblasting roughening on the surface of the spherical pipe joint on the air leak pipe at a sandblasting pressure of 0.20-0.40MPa, a sandblasting angle of 15°-45°, and a sandblasting distance of 100-250mm. This improves the adhesion between the coating and the surface of the spherical pipe joint on the air leak pipe during subsequent spraying. Furthermore, by sandblasting the surface of the spherical pipe joint on the air leak pipe, oxides and impurities on the surface of the spherical pipe joint on the air leak pipe are effectively removed. S4. Remove the air leak pipe from the sandblasting equipment after completing step S3, and clamp it onto the positioning fixture, such as... Figure 1 As shown, the positioning fixture includes a circular base 1, and a bushing 2 on the lower surface of the circular base 1. The central axis of the bushing 2 is on the same axis as the center of the circular base 1, and the inner diameter of the bushing 2 is adapted to the diameter of the rotating central shaft inside the sandblasting equipment. After the bushing 2 is fitted onto the rotating central shaft inside the sandblasting equipment, it is fixed by bolts, thereby fixing the positioning fixture on the rotating central shaft inside the sandblasting equipment. Meanwhile, a connecting component 3 and a support plate 4 are fixedly installed on the circular base 1 by bolts. The connecting component 3 is L-shaped, and the vertical part of the connecting component 3 is T-shaped. The connecting component 3 is used to clamp the conduit of the air leak pipe. When the air leak pipe is installed, the end face of the conduit on the air leak pipe is connected to the side of the vertical part of the connecting component 3, and the flange or connecting part of the end face of the conduit on the air leak pipe is fixed to the vertical part of the connecting component 3 by bolts. The top of the support plate 4 is also equipped with a clamping and positioning structure 5, which is an existing clamping structure; at the same time, the top of the support plate 4 is also equipped with a tooling component protective cover 6, which covers the clamping and positioning structure. The tooling component protective cover 6 is divided into left and right parts. One of the left and right parts is fixedly installed on the top of the support plate 4. The mating surfaces of the left and right parts are provided with an opening that matches the straight wall section of the spherical pipe joint on the air leakage pipe. The mating surfaces of the left and right parts also have outward folded edges on both sides. The two opposite folded edges on the left and right parts are fixed by bolts, so that the left and right parts together form a tooling component protective cover 6. The clamping and positioning structure 5 works together to clamp the straight wall section of the spherical pipe joint on the air leak pipe. After the air leak pipe is clamped on the clamping and positioning structure 5, the left and right parts of the tooling component protective cover 6 are fixed by bolts. The tooling component protective cover 6 covers the clamping and positioning structure 5, which effectively prevents the air leak pipe from being affected by the spray powder adhering to the clamping and positioning structure 5 during the subsequent spraying process. After the straight section of the spherical pipe joint on the air leak pipe is fixed on the clamping and positioning structure 5, the center of the spherical pipe joint on the air leak pipe is on the same straight line as the center of the circular base 1 and the central axis of the bushing 2. After the positioning fixture with the air leak pipe is installed in the sandblasting equipment, the center of the spherical pipe joint on the air leak pipe coincides with the rotation center of the plasma spraying equipment, laying the foundation for subsequent spraying. like Figure 2 As shown, when the air leak pipe is clamped on the positioning fixture, the conduit of the air leak pipe is fixed to the connecting component 3 by bolts. Then, a part of the protective cover 6 of the fixture component away from the support plate 4 is removed, and the cylindrical straight wall section below the spherical pipe joint on the air leak pipe is clamped on the clamping and positioning structure 5. Then, the left and right parts of the protective cover 6 of the fixture component are fixedly connected by bolts, so that the protective cover 6 of the fixture component clamps and fixes the cylindrical straight wall section below the spherical pipe joint on the air leak pipe to the clamping and positioning structure 5, so that the air leak pipe avoids the spherical pipe joint and conduit on the air leak pipe when clamped. It should be noted here that when the size of the air leak pipe to be repaired changes, the support plate of the corresponding height in the positioning fixture can be replaced to ensure that the air leak pipe can be fixedly clamped on the positioning fixture. Next, the positioning fixture with the air leak pipe clamped is sent into the plasma spraying equipment, and the bushing 2 on the positioning fixture is placed on the rotating central shaft inside the plasma spraying equipment. Then, the bushing 2 on the positioning fixture is fixed to the rotating central shaft inside the plasma spraying equipment. Next, the spraying material is copper-nickel-indium. The operating parameters of the plasma spraying equipment are: argon flow rate of 30-50 NL / min, nitrogen flow rate of 2-6 NL / min, current of 400-500A, voltage of 40-60V, powder feeding speed of 3-8 rpm, spraying distance of 100-200mm, and spraying angle of 45-90°, so that a copper-nickel-indium coating is formed on the surface of the spherical pipe joint on the air leak pipe. S6. Performance Testing: After completing step S5, loosen the fixing of the bushing 2 on the positioning fixture to the rotating center shaft inside the plasma spraying equipment. Remove the positioning fixture containing the air leak pipe from the plasma spraying equipment and remove the air leak pipe from the positioning fixture. Apply hot-spray adhesive to seal the air leak pipe opening to complete the repair of the air leak pipe. Figure 3 As shown; next, connect the repaired air leak pipe to the sealing test equipment, using kerosene as the medium, and maintain the pressure at 5-10 MPa for 10-15 minutes; if there is no leakage in the air leak pipe, the air leak pipe after repair is qualified for sealing; if there is leakage in the air leak pipe, the air leak pipe after repair is unqualified for sealing. After the air leak pipe has been inspected for leaks, remove it from the sealing test equipment and check the copper-nickel-indium coating on the surface of the spherical pipe joint for defects such as cracks, bubbles, chips, peeling, and flaking.

[0020] This invention employs a low-stress method to remove the metal sealing coating from the surface of the spherical pipe joint on the air leak pipe, effectively avoiding the impact and cutting forces caused by traditional sandblasting or machining. This ensures zero damage and zero deformation to the spherical pipe joint on the air leak pipe. Furthermore, by clamping the air leak pipe with positioning fixtures, the center of the spherical pipe joint on the air leak pipe is effectively ensured to coincide with the rotation center of the equipment during sandblasting and coating processes, ensuring uniform sandblasting and coating and guaranteeing the accuracy of sandblasting and coating.

[0021] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A method for near-net-shape repair of thin-walled spherical connectors for irregularly shaped conduits, characterized in that, The steps include the following: S1. Use a pliers to repair and remove the metal sealing coating on the spherical pipe joint of the air leak pipe; S2. Seal the opening of the air leak pipe; S3. Use sandblasting equipment to roughen the air leakage pipe by sandblasting; S4. Clamp the sandblasted and roughened air leakage pipe onto the positioning fixture; S5. Install the positioning fixture with the air leakage pipe inside the spraying equipment, and spray a metal sealing coating on the outside of the air leakage pipe. S6. Remove the air leak pipe from the positioning fixture and clean the air leak pipe opening. Check the air leak pipe for leaks.

2. The method for near-net-shape repair of thin-walled spherical joints of irregularly shaped conduits according to claim 1, characterized in that, The material used to seal the opening of the air leak pipe in step S2 is high-temperature resistant putty.

3. The method for near-net-shape repair of thin-walled spherical joints of irregularly shaped conduits according to claim 1, characterized in that, The positioning fixture in step S3 includes a circular base with bushings on the upper and lower surfaces. A connecting component and a support plate are also installed on the circular base. The connecting component is used to clamp the conduit of the air leakage pipe. A clamping and positioning structure is also installed on the top of the support plate. A detachable protective cover for the fixture components is installed on the clamping and positioning structure.

4. The method for near-net-shape repair of thin-walled spherical joints of irregularly shaped conduits according to claim 1, characterized in that, In step S4, when the sandblasting equipment roughens the air leakage pipe, the abrasive is white corundum or brown corundum, the diameter of the sandblasting nozzle is 10-15mm, the sandblasting pressure is 0.20-0.40MPa, the sandblasting angle is 15°-45°, and the sandblasting distance is 100-250mm.

5. The method for near-net-shape repair of thin-walled spherical joints of irregularly shaped conduits according to claim 1, characterized in that, In step S5, the metal sealing coating is a copper-nickel-indium coating, and the spraying method is plasma spraying. During the spraying process, the argon flow rate is 30-50 NL / min, the nitrogen flow rate is 2-6 NL / min, the current is 400-500 A, the voltage is 40-60 V, the powder feeding speed is 3-8 rpm, the spraying distance is 100-200 mm, and the spraying angle is 45-90°.

6. The method for near-net-shape repair of thin-walled spherical joints of irregularly shaped conduits according to claim 1, characterized in that, In step S6, the air leak pipe is checked using kerosene as the medium, at a pressure of 5-10 MPa, and for a pressure holding time of 10-15 minutes.

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