A method for repairing a hole damage of an end cover part

Abstract

The present application relates to the technical field of remanufacturing, in particular to a method for repairing the inner hole damage of an end cover part, comprising the following steps: removing the "boss-groove" feature of the inner hole of the end cover part to obtain a repaired part; designing an inner tool and an outer tool matched with the repaired part to form a combined part; designing a special repair alloy powder; preparing a simulated part of the repaired structure with the same material; performing a simulated repair test on the simulated part; detecting the performance of the simulated part after the simulated repair test; repairing the combined part in a determined process, and performing nondestructive testing and size recovery processing according to the product drawing after the repair is completed. The present application solves the engineering problems of limited accessibility of conventional repair welding, high repair defect rate, and easy deviation of repair size, greatly improves the success rate of damaged part repair, solves the problem of large amount of scrapped parts, designs a special repair alloy powder, and realizes efficient remodeling of the mechanical properties and corrosion resistance of the damaged end cover.

Description

Technical Field

[0001] This invention relates to the field of remanufacturing technology, specifically to a method for repairing damage to the inner hole of an end cap part. Background Technology

[0002] End caps are crucial components in aircraft electromechanical actuation systems, serving for sealing, piston rod support, and guidance. Their performance stability directly impacts the smooth operation of the actuation system. Due to the service environment, extensive pitting corrosion damage, and even rust and flaking, frequently occur at the inner hole grooves of these components during service, severely affecting the service life and safety of the actuation system.

[0003] For the failure mode of corrosion in the inner hole groove of end cap parts, the conventional repair method is to perform local welding to repair the damaged area. However, due to the space constraints of the product structure, the accessibility of welding repair at the corrosion site is poor. The welding process is prone to defects such as interface steps, weld porosity, and cracks, and subsequent machining dimensions are difficult to guarantee. All of these factors greatly increase the risk and cost of product maintenance. Therefore, it is urgent to develop a method that can meet the requirements for rapid recovery of such damaged parts. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for repairing damage to the inner hole of an end cap component. Unlike conventional "surface repair" methods, this method employs "volume repair" of the damaged area, integrally molding the non-working area, followed by precision machining, thereby achieving efficient remodeling of the damaged component's performance.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution:

[0006] A method for repairing damage to the inner hole of an end cap component includes the following steps:

[0007] S1. Remove the "boss-slot" feature from the inner hole of the end cap part to obtain the part to be repaired;

[0008] S2. Design matching internal and external tooling according to the shape of the inner and outer end faces of the end cap part. The internal tooling fits with the inner end face of the part to be repaired, and the external tooling fits with the outer end face of the part to be repaired to form an assembly.

[0009] S3. Design a special repair alloy powder. The mass percentage of each component in the special repair alloy powder is as follows: C≤0.05%, Mn≤0.30%, Cr: 12.2%-13.5%, Ni: 7.5%-8.5%, Mo: 2.0%-3.5%, N≤0.08%~0.13%.

[0010] S4. Based on the structural characteristics of the damaged end cap part, a simulated part of the structure to be repaired is prepared using the same material and restored accordingly. The simulated part is thoroughly cleaned with acetone for later use.

[0011] S5. Take a sufficient amount of alloy powder with a particle size range of 53μm to 150μm and thoroughly dry it in an oxygen-free environment for later use. The alloy powder must meet the requirements of D. 10 ≥53μm, 80μm≤D 50 ≤120μm, D 90 ≤165μm, flowability ≤20s / 50g, the ratio of alloy powder volume to volume to be repaired is 2.3~3.5;

[0012] S6. Conduct a simulated repair test on the simulated part, and then perform tempering treatment after the simulated repair test is completed.

[0013] The test parameters are as follows:

[0014] The extrusion pressure is 8MPa-10MPa, the pressurization rate is 5min / MPa-8min / MPa, the pressurization time is 20min-50min, the extrusion temperature is 700℃-900℃, and the holding time is 2h-5h.

[0015] S7. Perform performance testing on the simulated part after the simulated repair test. If the simulated part meets the performance test requirements, proceed to the next step. If it does not meet the requirements, return to S4 and repeat the operation until it meets the performance test requirements.

[0016] S8. Substitute the assembly from S2 into the processes determined in S3 to S7 for repair. After the repair is completed, remove the end cap part for non-destructive testing and restore the dimensions according to the product drawings.

[0017] Preferably, in step S1, the part to be repaired is thoroughly cleaned with anhydrous ethanol and acetone and then dried before use.

[0018] Preferably, the tempering process in step S6 is 500℃~650℃, followed by air cooling.

[0019] Preferably, the performance testing in step S7 includes metallographic structure performance testing, defect detection, hardness performance testing, and corrosion resistance performance testing.

[0020] Preferably, the performance testing requirements in step S7 include: uniform metallographic structure, no obvious grain distortion, and a microstructure rating of no more than level 3 according to GB / T 13320-2007; no pores or cracks; hardness of the repair layer meeting HV≥300; and corrosion resistance of the repair layer meeting the requirement that the corrosion rate of the repair layer under atmospheric conditions is ≤1mg / m³. 2 ·h.

[0021] The beneficial effects of this invention are:

[0022] This invention overcomes engineering challenges such as limited accessibility, high defect rate, and easy deviation in repair dimensions associated with conventional welding repair methods, significantly improving the success rate of repairing damaged parts and solving the problem of large scrap volume. A special repair alloy powder was designed, achieving efficient reshaping of the mechanical and corrosion resistance properties of damaged end cap parts. This method can be simultaneously extended to the repair of parts with thin walls, complex structures, etc. A special protective tooling for repair was designed, conforming to the structural characteristics of the end cap component, to limit the flow path of the powder during the repair process and prevent deformation of the end cap parts during the repair process. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0024] Figure 1 This is a schematic diagram of the internal structure of the end cap component;

[0025] Figure 2 for Figure 1 Enlarged structural diagram at point A in the diagram;

[0026] Figure 3 This is a schematic diagram of the end cap part and tooling of the present invention after assembly;

[0027] Figure 4 This is a schematic diagram of the vacuum extrusion molding process of metal powder according to the present invention;

[0028] Figure 5 This is a schematic diagram of the assembly after repair according to the present invention.

[0029] In the diagram: 1. End cap part; 2. Internal tooling; 3. External tooling. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1 As shown,

[0032] A method for repairing damage to the inner hole of an end cap component includes the following steps:

[0033] S1. Remove the "boss-slot" feature from the inner hole of end cap part 1 to obtain the part to be repaired.

[0034] like Figure 1 and Figure 2As shown, the inner wall of the end cap part 1 has three alternating sealing bosses and three grooves, which is crucial for ensuring the sealing performance of the component. The end faces, sides, and bottom surfaces of the bosses and grooves in the inner hole of end cap part 1 have dense pitting corrosion, reaching a depth of 0.2 mm. After removal, the part to be repaired is thoroughly cleaned with anhydrous ethanol and acetone and then dried before use.

[0035] In this embodiment, the inner diameter of the part to be repaired is 27.5 mm and the inner length is 31.5 mm.

[0036] S2. Based on the shapes of the inner and outer end faces of the end cap part 1, design matching inner tooling 2 and outer tooling 3. Inner tooling 2 mates with the inner end face of the part to be repaired, and outer tooling 3 mates with the outer end face of the part to be repaired, forming an assembly. The inner tooling 2 and outer tooling 3 are as follows: Figure 3 As shown.

[0037] S3. Based on the working environment, actuation characteristics, and functional properties of the end cap parts, a special repair alloy powder is designed to meet their service performance requirements. This aims to balance the mechanical and physicochemical properties of the repaired parts, achieving efficient repair of damaged components. The mass percentage of each component in the special repair alloy powder is as follows: C≤0.05%, Mn≤0.30%, Cr: 12.2%-13.5%, Ni: 7.5%-8.5%, Mo: 2.0%-3.5%, N≤0.08%~0.13%.

[0038] In this embodiment, the specific mass percentages of each component in the special repair alloy powder are as follows: C is 0.03%, Mn is 0.2%, Cr is 12.5%, Ni is 8.1%, Mo is 2.3%, and N is 0.1%.

[0039] S4. Based on the structural characteristics of the damaged part of end cap 1, a simulated part of the structure to be repaired is prepared using the same material and restored accordingly. The simulated part is thoroughly cleaned with acetone for later use.

[0040] S5. Take a sufficient amount of alloy powder with a particle size range of 53μm to 150μm and thoroughly dry it in an oxygen-free environment for later use. The alloy powder must meet the requirements of D. 10 ≥53μm, 80μm≤D 50 ≤120μm, D 90 The alloy powder has a thickness of ≤165μm and a flowability of ≤20s / 50g. The ratio of the volume of the alloy powder to the volume to be repaired is 2.3 to 3.5.

[0041] In this embodiment, 20 ml of loosely packaged alloy powder was taken and kept at 110°C for 2 hours in a vacuum drying oven.

[0042] S6. Conduct a simulated repair test on the simulated part, and then perform tempering treatment after the simulated repair test is completed.

[0043] The test parameters are as follows:

[0044] The extrusion pressure is 8MPa-10MPa, the pressurization rate is 5min / MPa-8min / MPa, the pressurization time is 20min-50min, the extrusion temperature is 700℃-900℃, and the holding time is 2h-5h.

[0045] In this embodiment, the specific test parameters are as follows: extrusion pressure of 8.5 MPa, pressurization rate of 5 min / MPa, pressurization time of 45 min, extrusion temperature of 880℃, and holding time of 3 h. After repair, the repaired part is tempered at 580℃ and then air-cooled.

[0046] S7. Perform performance testing on the simulated parts after the simulated repair test, including metallographic performance testing, defect detection, hardness testing, and corrosion resistance testing. Performance requirements include: uniform metallographic structure, no obvious grain distortion, and a microstructure rating of no more than level 3 according to GB / T 13320-2007; no porosity or cracks; hardness of the repair layer meeting HV≥300; and corrosion resistance of the repair layer meeting the requirement that the corrosion rate of the repair layer under atmospheric conditions is ≤1mg / m³. 2 h. If the simulated part meets the performance test requirements, proceed to the next step; otherwise, return to S4 and repeat the process until the performance test requirements are met.

[0047] S8. Substitute the assembly from S2 into the processes determined in S3 to S7 for repair. The repair process is as follows: Figure 4 As shown, the repair result is as follows Figure 5 As shown. After repair, non-destructive testing is performed, and the product is re-machined to its original dimensions according to the product drawings.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for repairing damage to the inner hole of an end cap part, characterized in that: Includes the following steps: S1. Remove the "boob-slot" feature from the inner hole of the end cap part (1) to obtain the part to be repaired; S2. Design an inner tooling (2) and an outer tooling (3) to match the inner and outer end face shapes of the end cap part (1). The inner tooling (2) is fitted with the inner end face of the part to be repaired, and the outer tooling (3) is fitted with the outer end face of the part to be repaired to form an assembly. S3. Design a special repair alloy powder. The mass percentage of each component in the special repair alloy powder is as follows: C≤0.05%, Mn≤0.30%, Cr: 12.2%-13.5%, Ni: 7.5%-8.5%, Mo: 2.0%-3.5%, N≤0.08%~0.13%. S4. Based on the structural characteristics of the damaged part of the end cap part (1), a simulated part of the structure to be repaired is prepared using the same material and restored accordingly. The simulated part is thoroughly cleaned with acetone for later use. S5. Take a sufficient amount of alloy powder with a particle size range of 53μm to 150μm and thoroughly dry it in an oxygen-free environment for later use. The alloy powder must meet the requirements of D. 10 ≥53μm, 80μm≤D 50 ≤120μm, D 90 ≤165μm, flowability ≤20s / 50g, the ratio of alloy powder volume to volume to be repaired is 2.3~3.5; S6. Conduct a simulated repair test on the simulated part, and then perform tempering treatment after the simulated repair test is completed. The test parameters are as follows: The extrusion pressure is 8MPa-10MPa, the pressurization rate is 5min / MPa-8min / MPa, the pressurization time is 20min-50min, the extrusion temperature is 700℃-900℃, and the holding time is 2h-5h. S7. Perform performance testing on the simulated part after the simulated repair test. If the simulated part meets the performance test requirements, proceed to the next step. If it does not meet the requirements, return to S4 and repeat the operation until it meets the performance test requirements. S8. Substitute the assembly in S2 into the process determined in S3 to S7 for repair. After the repair is completed, take out the end cap part (1) for non-destructive testing and restore the dimensions according to the product drawings.

2. The method for repairing damage to the inner hole of an end cap part according to claim 1, characterized in that: In step S1, the part to be repaired is thoroughly cleaned with anhydrous ethanol and acetone and then dried for later use.

3. The method for repairing damage to the inner hole of an end cap part according to claim 1, characterized in that: In step S6, the tempering process is carried out at 500℃~650℃, followed by air cooling.

4. The method for repairing damage to the inner hole of an end cap part according to claim 1, characterized in that: The performance testing in step S7 includes metallographic structure performance testing, defect detection, hardness performance testing, and corrosion resistance performance testing.

5. The method for repairing damage to the inner hole of an end cap part according to claim 4, characterized in that: The performance testing requirements in step S7 include: uniform metallographic structure, no obvious grain distortion, and a microstructure rating of no more than level 3 according to GB / T13320-2007; no pores or cracks; hardness of the repair layer meeting HV≥300; and corrosion resistance of the repair layer meeting the requirement that the corrosion rate of the repair layer under atmospheric conditions is ≤1mg / m³. 2 ·h.

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