Vacuum oscillation hot-pressing repair method for copper-steel rotor of hydraulic pump

Abstract

The present application relates to the technical field of remanufacturing, in particular to a vacuum oscillation hot-pressing repair method for copper-steel rotor of hydraulic pump, which comprises the following steps: polishing the corroded and worn copper alloy end face of the hydraulic pump rotor; processing corresponding copper alloy ring patch; placing the hydraulic pump rotor into the lower tool, with the copper alloy end face of the hydraulic pump rotor facing upward; fixing the copper alloy ring patch to the lower part of the upper tool through the spring buckle at the bottom of the upper tool; the upper tool, the copper alloy ring patch, the hydraulic pump rotor and the lower tool jointly form a to-be-processed connecting assembly; performing oscillation hot-pressing repair; and performing nondestructive testing. Through bidirectional pressing of the upper and lower pressing heads and superimposed vibration pressure of medium frequency, the present application can form dense connection between copper alloys under the conditions of lower temperature and shorter time, thereby reducing energy consumption, improving product quality, guaranteeing high-quality repair of high-value-added hydraulic pump rotor and greatly reducing product maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of remanufacturing technology, specifically to a method for vacuum oscillation hot pressing repair of a copper-steel rotor for a hydraulic pump. Background Technology

[0002] Hydraulic products made of bimetallic copper and steel can fully utilize the excellent corrosion resistance, wear resistance, and lubrication properties of copper alloys, as well as the high strength of steel, significantly improving the power-to-weight ratio of hydraulic products. However, hydraulic products, especially rotor-type products, inevitably experience some wear on the copper alloy end faces during long-term high-speed operation, which may compromise the reliable operation of the rotor's critical precision friction pairs.

[0003] Currently, repair techniques for copper alloys include gas welding, brazing, manual arc welding, TIG welding, and electron beam welding. However, these techniques result in poor performance and numerous defects after welding. Therefore, no effective repair technology has yet been proposed to address the wear problem of the copper alloy end face of high-value-added hydraulic pump copper-steel rotors. Worn high-value-added hydraulic pump rotors can only be replaced, leading to extremely high economic costs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a vacuum oscillation hot pressing repair method for copper-steel rotors of hydraulic pumps.

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

[0006] A method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump includes the following steps:

[0007] S1. Grind the corroded and worn copper alloy end face of the hydraulic pump rotor, then clean it with ultrasonic in acetone, and then blow it dry for later use.

[0008] S2. Using the same material as the copper alloy end face of the hydraulic pump rotor, the copper alloy ring patch is processed into a corresponding copper alloy ring patch according to the groove shape of the copper alloy end face of the hydraulic pump rotor. The surface of the copper alloy ring patch is then polished, cleaned, and dried for later use.

[0009] S3. Place the hydraulic pump rotor into the lower fixture, with the copper alloy end face of the hydraulic pump rotor facing upwards.

[0010] S4. Secure the copper alloy ring patch to the lower part of the upper fixture using the spring clip at the bottom of the upper fixture;

[0011] S5. Position the upper tooling by using the boss at the bottom of the upper tooling and the groove on the hydraulic pump rotor. Place the upper tooling and the copper alloy ring patch together on top of the hydraulic pump rotor. Under the support of the spring clip, there is a certain distance between the lower end face of the copper alloy ring patch and the copper alloy end face of the hydraulic pump rotor. The upper tooling, the copper alloy ring patch, the hydraulic pump rotor, and the lower tooling together form the connection assembly to be processed.

[0012] S6. Place the assembly to be processed between the upper and lower pressure heads of the vibrating hot press furnace, close the furnace door, evacuate the furnace, and then perform vibrating hot pressing repair. The vibrating hot pressing repair process is as follows:

[0013] First, when the vacuum level is not higher than 100Pa, apply a pre-pressure of 0.5-1.0MPa to the connection component to be processed, start heating, heating rate of 10-15℃ / min, heat to 500-580℃, and hold for 2-4 hours. At the same time, apply an axial oscillation pressure of 15-35MPa to the connection component to be processed, with an oscillation pressure amplitude of 8-10MPa and an oscillation pressure frequency of 20-40Hz.

[0014] S7. After the furnace cools down, the pressure is released, and after the temperature reaches room temperature, the hatch is opened and the repaired connecting components are taken out.

[0015] S8. Remove the repaired hydraulic pump rotor from the tooling and perform non-destructive testing. If there are no internal cracks or gaps, it is qualified. Machining is performed according to the drawing requirements to remove excess material and restore the original dimensions of the hydraulic pump rotor to complete the repair. Otherwise, the copper alloy end face of the hydraulic pump rotor is re-grinded and oscillation hot pressing repair is performed again.

[0016] Preferably, in step S1, the grinding depth of the copper alloy end face of the hydraulic pump rotor that is corroded and worn is 1 mm.

[0017] Preferably, the thickness of the copper alloy ring patch in step S2 is 2 mm.

[0018] Preferably, in step S3, the lower tooling has a bowl-shaped structure, and a 2mm gap is left between the bottom of the lower tooling and the lowest surface of the hydraulic pump rotor.

[0019] Preferably, the thickness of the boss in step S4 is 3mm.

[0020] Preferably, in step S7, the temperature is reduced at a rate of 20°C / min, and the pressure is released when the temperature drops to 200°C.

[0021] Preferably, the non-destructive testing method in step S8 is X-ray flaw detection.

[0022] The beneficial effects of this invention are:

[0023] This invention utilizes bidirectional pressure from upper and lower pressure heads, along with superimposed mid-frequency vibration pressure, to form a dense connection between copper alloys under relatively low temperature and short time conditions. This reduces energy consumption while improving product quality, ensuring high-quality repair of high-value-added hydraulic pump rotors, and significantly reducing product maintenance costs. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0025] Figure 1 This is a schematic diagram showing the corrosion and wear of the copper alloy end face of the hydraulic pump rotor of the present invention;

[0026] Figure 2 This is a schematic diagram of the copper alloy end face of the hydraulic pump rotor after grinding according to the present invention;

[0027] Figure 3 This is a schematic diagram of the copper alloy ring patch structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the tooling structure of the present invention;

[0029] Figure 5 This is a schematic diagram of the tooling structure of the present invention;

[0030] Figure 6 This is a cross-sectional schematic diagram of the connecting component of the present invention;

[0031] Figure 7 This is a schematic diagram of the copper alloy end face of the hydraulic pump rotor after the repair according to the present invention.

[0032] In the diagram: 1. Hydraulic pump rotor; 2. Copper alloy ring patch; 3. Lower tooling; 4. Upper tooling; 5. Spring clip; 6. Boss; 7. Groove. Detailed Implementation

[0033] 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.

[0034] A method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump includes the following steps:

[0035] S1. Grind the corroded and worn copper alloy end face of the hydraulic pump rotor 1, such as... Figure 1 The diagram shows the corroded and worn copper alloy end face of the hydraulic pump rotor 1. The grinding depth is approximately 1mm, followed by ultrasonic cleaning in acetone and then drying. The structure after grinding is shown below. Figure 2 As shown.

[0036] S2. Using the same material as the copper alloy end face of the hydraulic pump rotor 1, specifically ZQCu10-2-3 material in this embodiment, a corresponding copper alloy annular patch 2 is machined according to the groove 7 of the copper alloy end face of the hydraulic pump rotor 1. The thickness of the copper alloy annular patch 2 is 2mm, so that a 1mm machining allowance is retained after oscillating hot pressing. The surface of the copper alloy annular patch 2 is polished and cleaned, and then dried for later use. The structure of the copper alloy annular patch 2 is as follows: Figure 3 As shown.

[0037] S3. Place the hydraulic pump rotor 1 into the lower fixture 3, with the copper alloy end face of the hydraulic pump rotor 1 facing upwards. The structure of the lower fixture 3 is as follows: Figure 4 As shown. The lower fixture 3 has a bowl-shaped structure, and the lower end of the hydraulic pump rotor 1 can be embedded in its circular groove to ensure vertical and stable placement. Considering that the lowest surface of the hydraulic pump rotor 1 is a precision assembly surface, a 2mm gap is left between it and the lower fixture 3 to avoid deformation of the lowest end of the hydraulic pump rotor 1 under pressure.

[0038] S4. The copper alloy ring patch 2 is fixed to the lower part of the upper tooling 4 using the spring clip 5 at the bottom of the upper tooling 4. The structure of the upper tooling 4 is as follows: Figure 5 As shown.

[0039] S5. Positioning is achieved by using the boss 6 at the bottom of the upper tooling 4 and the groove 7 on the hydraulic pump rotor 1. The boss 6 has a thickness of 3mm, ensuring accurate relative positioning of the upper tooling, the annular patch, and the hydraulic pump rotor. The upper tooling 4 and the copper alloy annular patch 2 are placed together above the hydraulic pump rotor 1. Supported by the spring clip 5, there is a certain distance between the lower end face of the copper alloy annular patch 2 and the copper alloy end face of the hydraulic pump rotor 1. This distance facilitates the expulsion of gas between the lower end face of the copper alloy annular patch 2 and the copper alloy end face of the hydraulic pump rotor 1 during subsequent vacuuming. If the spring clip 5 is not provided, there will be no distance between the lower end face of the copper alloy annular patch 2 and the copper alloy end face of the hydraulic pump rotor 1, potentially causing gas residue between them during vacuuming, resulting in incomplete fusion defects after hot pressing. The upper tooling 4, the copper alloy annular patch 2, the hydraulic pump rotor 1, and the lower tooling 3 together form the assembly to be processed.

[0040] S6. Place the assembly to be processed between the upper and lower pressure heads of the vibrating hot press furnace, close the furnace door, evacuate the furnace, and then perform vibrating hot pressing repair. The vibrating hot pressing repair process is as follows:

[0041] First, when the vacuum level is not higher than 100Pa, apply a pre-pressure of 0.5-1.0MPa to the connection component to be processed, start heating, heating rate of 10-15℃ / min, heat to 500-580℃, and hold for 2-4 hours. At the same time, apply an axial oscillation pressure of 15-35MPa to the connection component to be processed, with an oscillation pressure amplitude of 8-10MPa and an oscillation pressure frequency of 20-40Hz.

[0042] Specifically, in this embodiment, a vacuum of 50 Pa is drawn, and a pre-pressure of 0.8 MPa is applied to the assembly to be processed. Under this pressure, the spring clip deforms, and the lower end face of the copper alloy ring patch fits tightly against the upper end face of the hydraulic pump rotor. Heating begins and reaches 550°C, with a holding time of 2 hours. Simultaneously, an axial oscillation pressure of 20 MPa is applied to the assembly to be processed, with an amplitude of 10 MPa and a frequency of 30 Hz. This ensures metallurgical bonding between the copper alloy components.

[0043] S7. After the connecting components are oscillating and hot-pressed, release the pressure and cool down at a rate of 20℃ / min. When the temperature drops to 200℃, release the pressure between the upper and lower pressure heads. After cooling to room temperature, restore the furnace pressure to atmospheric pressure, open the hatch, and take out the repaired connecting components.

[0044] S8. Remove the repaired hydraulic pump rotor 1 from the tooling and perform X-ray non-destructive testing. If there are no internal cracks or gaps, it is qualified. Machining is performed according to the drawing requirements to remove excess material and restore the original size of the hydraulic pump rotor 1 to complete the repair. Otherwise, the copper alloy end face of the hydraulic pump rotor 1 is re-grinded and the oscillation hot pressing repair is performed again.

[0045] Based on the above embodiments, shear specimens were prepared using the same method, and their mechanical properties were verified. The results are shown in Table 1.

[0046] Table 1 Comparison of performance between conventional repair and vacuum vibration hot pressing repair

[0047] sample Shear strength / MPa parent material 258 Conventional welding repair 202 Vacuum oscillation hot pressing repair 249

[0048] As shown in Table 1, the mechanical properties of the products repaired by vacuum oscillation hot pressing sintering are similar to those of the base material, and are significantly higher than those of the samples repaired by conventional diffusion welding.

[0049] 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 vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump, characterized in that: Includes the following steps: S1. Grind the corroded and worn copper alloy end face of the hydraulic pump rotor (1), then clean it with ultrasonic in acetone, and then blow it dry for later use. S2. Using the same material as the copper alloy end face of the hydraulic pump rotor (1), the corresponding copper alloy ring patch (2) is processed according to the groove (7) of the copper alloy end face of the hydraulic pump rotor (1), and the surface of the copper alloy ring patch (2) is polished, cleaned, and then dried for later use. S3. Place the hydraulic pump rotor (1) into the lower tooling (3), with the copper alloy end face of the hydraulic pump rotor (1) facing upwards. S4. Fix the copper alloy ring patch (2) to the lower part of the upper tooling (4) using the spring clip (5) at the bottom of the upper tooling (4); S5. Position the upper tooling (4) by using the boss (6) at the bottom of the upper tooling (4) and the groove (7) on the hydraulic pump rotor (1). Place the upper tooling (4) and the copper alloy ring patch (2) together on the upper surface of the hydraulic pump rotor (1). Under the support of the spring clip (5), there is a certain distance between the lower end face of the copper alloy ring patch (2) and the copper alloy end face of the hydraulic pump rotor (1). The upper tooling (4), the copper alloy ring patch (2), the hydraulic pump rotor (1), and the lower tooling (3) together form the connection assembly to be processed. S6. Place the assembly to be processed between the upper and lower pressure heads of the vibrating hot press furnace, close the furnace door, evacuate the furnace, and then perform vibrating hot pressing repair. The vibrating hot pressing repair process is as follows: First, when the vacuum level is not higher than 100Pa, apply a pre-pressure of 0.5-1.0MPa to the connection component to be processed, start heating, heating rate of 10-15℃ / min, heat to 500-580℃, and hold for 2-4 hours. At the same time, apply an axial oscillation pressure of 15-35MPa to the connection component to be processed, with an oscillation pressure amplitude of 8-10MPa and an oscillation pressure frequency of 20-40Hz. S7. After the furnace cools down, the pressure is released, and after the temperature reaches room temperature, the hatch is opened and the repaired connecting components are taken out. S8. Remove the repaired hydraulic pump rotor (1) from the tooling and perform non-destructive testing. If there are no internal cracks or gaps, it is qualified. Machining is performed according to the drawing requirements to remove excess material and restore the original size of the hydraulic pump rotor (1) to complete the repair. Otherwise, the copper alloy end face of the hydraulic pump rotor (1) is re-grinded and oscillating hot pressing repair is performed again.

2. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: In step S1, the grinding depth of the copper alloy end face of the hydraulic pump rotor (1) that is corroded and worn is 1mm.

3. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: In step S2, the thickness of the copper alloy ring patch (2) is 2mm.

4. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: In step S3, the lower tooling (3) has a bowl-shaped structure, and there is a 2mm gap between the bottom of the lower tooling (3) and the bottom surface of the hydraulic pump rotor (1).

5. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: In step S4, the thickness of the boss (6) is 3mm.

6. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: In step S7, the temperature is reduced at a rate of 20℃ / min, and the pressure is released when the temperature drops to 200℃.

7. The method for vacuum oscillation hot pressing repair of a copper-steel rotor of a hydraulic pump according to claim 1, characterized in that: The non-destructive testing method in step S8 is X-ray flaw detection.

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