Manufacturing method of a highly airtight sealing overlapping ring and the sealing overlapping ring

Abstract

The present invention discloses a manufacturing method of a highly airtight sealing overlapping ring and the sealing overlapping ring, belonging to the technical field of precision metal seals. The method comprises the following steps: selecting an H65 brass sheet containing 0.3-0.6% Si, and refining the grains to ≥ grade 8 through low-oxygen annealing; performing progressive die stamping after laser cutting, adopting a process of pre-bending 30° + final bending 88° compensation angle, and controlling the thinning rate ≤ 15% by combining hydraulic shaping; finally, forming a composite protective layer through pre-nickel plating, imitation gold electroplating and molybdate sealing. The present invention solves the problems of large bending springback, poor airtightness and short coating life of traditional seals, with a leakage rate ≤ 1×10⁻⁶ Pa·m³ / s and a salt spray life ≥ 1200 h, and is applicable to high-pressure hydraulic systems and the aerospace field.

Description

Technical Field

[0001] The present invention relates to the technical field of sealed laminated rings, and particularly to a manufacturing method and a sealed laminated ring of a high airtightness sealed laminated ring. Background Art

[0002] Since metal sealed laminated rings need to withstand high pressure, high-frequency dynamic loads and complex working conditions, extremely high requirements are imposed on the strength, fatigue resistance of materials and the machining accuracy of sealing surfaces. The manufacturing of traditional brass seals has the following problems:

[0003] Bending process defect: When forming a Z-shaped bend, the springback amount is large (≥3°), resulting in insufficient fitting degree of the sealing surface and a decrease in airtightness;

[0004] Risk of machining cracking: The thinning rate in the brass bending area exceeds the limit (>20%), and microcracks are easily generated, affecting the service life;

[0005] Insufficient surface corrosion resistance: The salt spray test life of conventional coatings is only 48 - 72h, which is difficult to meet the requirements of harsh environments.

[0006] In the prior art, such as the Chinese invention patent with the publication number CN103484781A, the plasticity of brass is improved by optimizing the annealing process, but the coordinated control problem of bending accuracy and coating performance is not solved. Therefore, there is an urgent need for a manufacturing method of a sealed laminated ring that takes into account high-precision forming, material strength and long-term anti-corrosion. Summary of the Invention

[0007] (I) Technical Problems to be Solved

[0008] To solve the above problems, the present invention proposes a manufacturing method and a sealed laminated ring of a high airtightness sealed laminated ring, aiming to solve the problems of bending process defects, risk of machining cracking and insufficient surface corrosion resistance of the sealed laminated ring in the prior art.

[0009] (II) Technical Solutions

[0010] For a manufacturing method of a high airtightness sealed laminated ring of the present invention, the components of the sealed laminated ring are by mass percentage: Cu 64 - 68%, Si 0.3 - 0.6%, the balance being Zn, impurity Pb ≤ 0.02%, impurity Fe ≤ 0.1%;

[0011] The manufacturing method of the high airtightness sealed laminated ring includes the following steps:

[0012] S100. Select an H65 brass sheet, and verify through a spectroscopic device that the Si content of the H65 brass sheet accounts for 0.3 - 0.6% of the total mass of the sealed laminated ring;

[0013] S200. Anneal the verified H65 brass sheet in step S100 using a nitrogen protection annealing device, then soak the H65 brass sheet in an alkaline degreasing solution using an ultrasonic cleaning device, and dry it after washing with water;

[0014] S300. Use a fiber laser cutting device to cut the H65 brass sheet processed in step S200. Calibrate the position of the sheet with a CCD vision positioning system. After cutting, the outer diameter is Φ50 ± 0.05 mm, and the inner diameter is Φ44 ± 0.05 mm. Use a vibratory grinding machine to remove the burrs on the cutting edge, with Ra ≤ 1.6 μm;

[0015] S400. Use a progressive die to stamp the sheet after deburring in step S300. The progressive die stamping includes three stations: punching, pre-bending, and final bending. Among them, when pre-bending, the upper die R angle is 0.6 mm, the pressure is 80 kN, and the bending angle is 30 ± 1°. When final bending, the compensation angle is 88°, the pressure is 120 kN, the springback compensation amount is 2°, and the step difference is 1.8 ± 0.03 mm. Finally, a ring body is obtained;

[0016] S500. Use an aging furnace to keep the ring body obtained in step S400 warm, and then air-cool it to room temperature;

[0017] S600. Use CNC precision machining to cut the sealing surface, pre-plate nickel on the ring body after cutting, and then perform imitation gold electroplating and sealing treatment to obtain a sealing stacked ring.

[0018] In the present invention, the oxygen content in the nitrogen protection annealing device in step S200 should be ≤ 50 ppm, and it is kept warm at 450 °C for 30 min. After the temperature in the device drops to 200 °C, it is air-cooled to normal temperature;

[0019] The alkaline degreasing solution includes NaOH and Na 2 CO 3 , where the content of NaOH is 50 g / L and the content of Na 2 CO 3 is 30 g / L. The H65 brass sheet is soaked in the alkaline degreasing solution at 60 °C for 5 min.

[0020] In the present invention, the medium used in the vibratory grinding machine in step S300 is ceramic balls.

[0021] In the present invention, in step S400, it also includes hydroforming the ring body. When hydroforming, it is necessary to keep the pressure for 5 seconds to eliminate local stress and ensure that the thickness reduction rate in the bending area is ≤ 15%.

[0022] In the present invention, in step S600, the spindle speed of the numerically controlled machine tool for cutting is 1500 rpm, the feed rate is 0.1 mm / r, and the cutting depth is 0.05 mm;

[0023] When pre-plating nickel, a Watts nickel solution is used to pre-electroplate the ring body. The neutral value of the Watts nickel solution is pH 4.0, the temperature is 55 °C. When pre-plating nickel, the cathode moving speed is 2 m / min, the current density is 3 A / dm² for 5 min, and the coating thickness is 3 ± 0.5 μm;

[0024] The components of the imitation gold plating bath are 35 g / L of CuCN, 10 g / L of ZnO, 8 g / L of Na 2 SnO 3 , the pH value is 12.5. When performing imitation gold plating, the temperature of the plating bath is 55 °C, the cathode current density is 1.5 A / dm² for 90 s, and the coating thickness is 2 ± 0.3 μm.

[0025] In the present invention, after the imitation gold plating is completed, the sealed laminated ring is immersed in a molybdate solution for 60 s, and then dried by hot air at 80 °C to increase the corrosion resistance of the sealed laminated ring.

[0026] Another sealed laminated ring of the present invention is made by the manufacturing method of the highly airtight sealed laminated ring described in the above technical solution. The sealed laminated ring includes a tail part, a bent part, and a head part. A first notch is provided at the end of the head part, and a second notch is provided at the end of the tail part. Both the first notch and the second notch face the bent part.

[0027] In the present invention, the head part is arranged on one side of the bent part, and the tail part is arranged on the other side of the bent part.

[0028] (III) Beneficial effects

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] In the present invention, through Si element microalloying (0.3 - 0.6%) combined with low-oxygen annealing (oxygen content ≤ 50 ppm), the grain size is ≥ grade 8, the leakage rate is ≤ 1×10⁻ 6 Pa·m³ / s, and the salt spray life is ≥ 1200 h, which is 3 - 5 times higher than the traditional scheme.

[0031] In the present invention, hydraulic shaping reduces the bending thinning rate to ≤ 15%, the step tolerance is ±0.03 mm, avoiding microcracks and ensuring the sealing surface fit. Through pre-plating nickel, imitation gold plating, and molybdate sealing, the adhesion of the coating is effectively increased, and the salt spray resistance performance is improved to ≥ 1000 h, breaking through the bottleneck of the traditional coating life of less than 72 h. Description of the drawings

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0033] Figure 1 It is a schematic flowchart of the manufacturing method;

[0034] Figure 2 It is a metallographic schematic diagram of the sheet metal after annealing in Embodiment 1;

[0035] Figure 3 It is a metallographic schematic diagram of the sealing laminated ring in Embodiment 1;

[0036] Figure 4 It is a three-dimensional structural schematic diagram of the sealing laminated ring.

[0037] 10. Head, 101. First notch, 20. Bending part, 30. Tail, 301. Second notch. Detailed implementation manners

[0038] Embodiment 1

[0039] As Figures 1 - 3 shown, a manufacturing method of a high-airtightness sealing laminated ring is disclosed. In this embodiment, the composition of the sealing laminated ring by mass percentage is: Cu 66%, Si 0.5%, Zn balance, impurity Pb ≤ 0.015%, impurity Fe ≤ 0.08%;

[0040] The manufacturing method of the high-airtightness sealing laminated ring includes the following steps:

[0041] S100. Material selection: Select H65 brass sheet with a thickness of 1.21 mm. Verify that the Si content of the H65 brass sheet accounts for 0.5% of the total mass of the sealing laminated ring through a spectrometer, such as an Olympus XRF analyzer;

[0042] S200. Material pretreatment: Use a nitrogen-protected annealing furnace to anneal the verified H65 brass sheet in step S100 at 450°C for 30 minutes. After completion, wait for the ambient temperature in the nitrogen-protected annealing furnace to reach 200°C and then perform air cooling inside it to make the temperature of the H65 brass sheet drop to room temperature. In particular, it is necessary to keep the oxygen content in the nitrogen-protected annealing furnace ≤ 50 ppm in real time.

[0043] Then use an ultrasonic cleaning device to soak the H65 brass sheet with an alkaline degreasing solution, and wash and dry it after water washing;

[0044] Among them, the alkaline degreasing solution consists of NaOH and Na 2 CO 3 and the content of NaOH is 50 g / L and that of Na 2 CO 3 is 30 g / L. The H65 brass sheet is immersed in the alkaline degreasing solution at 60 °C for 5 min to complete the pretreatment of H65, so that it meets the requirement of grain size ≥ 8 grades (detected by metallurgical microscope).

[0045] S300, Precision blanking: Use a fiber laser cutting machine to cut the H65 brass sheet processed in step S200, and calibrate the position of the sheet by a CCD vision positioning system. In particular, the fiber laser cutting machine is a TRUMPF TruLaser 5030, that is, it needs to be equipped with a nitrogen auxiliary system to prevent the cutting surface from oxidizing during cutting. The power during cutting is 2 kW, the cutting speed is 4 m / min, the nitrogen pressure is 0.8 MPa, and the focal position is ±0.1 mm.

[0046] After cutting, the outer diameter is Φ50.02 mm and the inner diameter is Φ44.03 mm. Use a vibratory grinding machine to remove the burrs on the cutting edge, with Ra ≤ 1.6 μm, where the grinding medium of the vibratory grinding machine is ceramic balls;

[0047] S400, Z-shaped bending forming: Use a progressive die to stamp the sheet after removing burrs in step S300. The progressive die stamping includes three stations: punching, pre-bending, and final bending. Among them, when pre-bending, the upper die R angle is 0.6 mm, the pressure is 80 kN, and the bending angle is 30°. In particular, the bending angle is real-time feedback by an angle sensor. When finally bending, the compensation angle is 88°, the pressure is 120 kN, the springback compensation amount is 2°, and the step difference is 1.8 ± 0.03 mm.

[0048] After completing the three-stage Z-shaped bending, use a four-column hydraulic press (pressure is 150 kN) to hold the pressure for 5 s to eliminate local stress, ensure that the thickness reduction rate of the bending area ≤ 15%, and finally obtain a ring body.

[0049] S500, Aging strengthening treatment: Use an aging furnace to heat-insulate the ring body obtained in step S400. In particular, the ring body obtained in step S400 is heat-insulated in an aging furnace at 260 °C for 2 h, and then air-cooled to room temperature to make its hardness reach HV125.

[0050] S600, CNC precision machining and surface composite plating: Use CNC precision machining to cut the sealing surface, pre-plate nickel on the cut ring body, and then perform imitation gold electroplating and sealing treatment to obtain a sealing stacked ring.

[0051] In step S600, the spindle speed of the CNC machine tool for cutting is 1500 rpm, the feed rate is 0.1 mm / r, and the cutting depth is 0.05 mm;

[0052] During pre-nickel plating, the ring body is pre-electroplated with Watt nickel solution. The neutral value of the Watt nickel solution is pH 4.0, the temperature is 55 °C. During pre-nickel plating, the cathode moving speed is 2 m / min, the current density is 3 A / dm² for 5 min, and the coating thickness is 3.2 μm;

[0053] The components of the imitation gold plating bath are 35 g / L of CuCN, 10 g / L of ZnO, 8 g / L of Na 2 SnO 3 , the pH value is 12.5. During imitation gold plating, the temperature of the plating bath is 55 °C, the cathode current density is 1.5 A / dm² for 90 s, and the coating thickness is 2.1 μm.

[0054] After the imitation gold plating is completed, the sealed laminated ring is immersed in the molybdate solution for 60 s, and then dried by hot air at 80 °C to enhance the corrosion resistance of the sealed laminated ring.

[0055] As Figure 4 shown, in this embodiment, a sealed laminated ring is also disclosed, which includes a tail part, a bending part and a head part. A first notch is provided at the end of the head part, and a second notch is provided at the end of the tail part. Both the first notch and the second notch are arranged towards the bending part. The head part is arranged on one side of the bending part, and the tail part is arranged on the other side of the bending part.

[0056] Example 2

[0057] The difference from Example 1 is that the composition of the sealed laminated ring by mass percentage is: Cu 64%, Si 0.3%, Zn balance, impurity Pb ≤ 0.02%, impurity Fe ≤ 0.1%;

[0058] During the material pretreatment in step S200, the verified H65 brass sheet in step S100 is annealed at 440 °C for 35 min using a nitrogen protection annealing furnace. After completion, wait for the ambient temperature in the nitrogen protection annealing furnace to reach 200 °C and then perform air cooling inside it, so that the temperature of the H65 brass sheet drops to room temperature.

[0059] During laser cutting in step S300, the power is 2.2 kW, the cutting speed is 3.8 m / min, the outer diameter after cutting is Φ50.05 mm, and the inner diameter is Φ44.05 mm.

[0060] In step S400, the pre-bending is 32°, the final bending compensation angle is 87°, the step difference is 1.78 mm, and the thinning rate is 14%.

[0061] In step S500, the thickness of the imitation gold plating layer is 1.9 μm.

[0062] Example 3

[0063] The difference from Example 1 is that the composition of the sealing laminated ring by mass percentage is: Cu 68%, Si 0.6%, the balance Zn, impurity Pb ≤ 0.01%, impurity Fe ≤ 0.05%;

[0064] When performing material pretreatment in step S200, the verified H65 brass sheet in step S100 is annealed at 460 °C for 25 min using a nitrogen protection annealing furnace. After completion, wait for the ambient temperature in the nitrogen protection annealing furnace to reach 200 °C and then perform air cooling inside it, so that the temperature of the H65 brass sheet drops to room temperature.

[0065] In step S400, the final bending compensation angle is 89°, the step difference is 1.83 mm, and the thinning rate is 11%.

[0066] In step S500, the thickness of the pre-nickel plating layer is 3.5 μm.

[0067] Example 4

[0068] The difference from Example 1 is that the composition of the sealing laminated ring by mass percentage is: Cu 65%, Si 0.4%, the balance Zn;

[0069] When performing laser cutting in step S300, the cutting speed is 4.2 m / min, and the outer diameter after cutting is Φ49.98 mm.

[0070] In step S400, the hydraulic shaping pressure is 160 kN, and the step difference is 1.79 mm.

[0071] Example 5

[0072] The difference from Example 1 is that when performing material pretreatment in step S200, the verified H65 brass sheet in step S100 is annealed at 430 °C for 40 min using a nitrogen protection annealing furnace. After completion, wait for the ambient temperature in the nitrogen protection annealing furnace to reach 200 °C and then perform air cooling inside it, so that the temperature of the H65 brass sheet drops to room temperature. And the final grain size ≥ 9 grades.

[0073] In step S500, the temperature of the imitation gold plating solution is 60 °C, and the coating thickness is 2.3 μm.

[0074] Example 6

[0075] The difference from Example 1 is that the composition of the sealing laminated ring is by mass percentage: Cu 66%, Si 0.55%, Zn the balance, impurity Pb ≤ 0.015%, impurity Fe ≤ 0.07%;

[0076] In step S400, pre-bend at 28°, and the final bend is at 86° compensation angle.

[0077] Example 7

[0078] The difference from Example 1 is that after molybdate sealing in step S600, the thickness of the oxide film is 0.5 μm.

[0079] Example 8

[0080] The difference from Example 1 is that the composition of the sealing laminated ring is by mass percentage: Cu 66%, Zn the balance, impurity Pb ≤ 0.015%, impurity Fe ≤ 0.07%; that is, compared with Example 1, Si is not added in this example.

[0081] In step S200, the annealing temperature is 450 °C, and in step S400, the final bend is 90° (without compensation angle).

[0082] Example 9

[0083] The difference from Example 1 is that in step S200, during annealing, the oxygen content in the nitrogen protection annealing furnace is 200 ppm, the annealing temperature is 450 °C and it lasts for 30 min.

[0084] Example 10

[0085] The difference from Example 1 is that in step S400, the hydraulic step is missing, and directly perform the aging treatment in S500.

[0086] Comparative analysis of technical effects:

[0087] 1. Improvement of performance by Si element

[0088] Examples 1 - 7: Si content is 0.3 - 0.6%, grain size ≥ 8 grades, thinning rate ≤ 15%, leakage rate ≤ 1×10⁻ 6 Pa·m³ / s.

[0089] Example 8 (without Si): Grain coarsening (6.5 grades), thinning rate 22%, leakage rate deteriorated to 5×10⁻ 5 , salt spray life is only 240 h.

[0090] Conclusion: The Si element significantly improves the sealing performance and corrosion resistance by refining grains and inhibiting crack propagation.

[0091] 2. Control of annealing oxygen content

[0092] Example 1: Oxygen content ≤ 50 ppm, grain size 8.5, hardness HV125.

[0093] Example 9 (oxygen content 200 ppm): Grain coarsening to grade 6.0, hardness reduced to HV100, salt spray life only 500 h.

[0094] Conclusion: Low-oxygen annealing avoids oxidation embrittlement and ensures material plasticity and coating adhesion.

[0095] 3. Necessity of hydraulic shaping

[0096] Example 1: Step difference 1.81 mm (tolerance ±0.03 mm), leakage rate 8×10⁻ 7 .

[0097] Example 10 (not shaped): Step difference 1.92 mm (out of tolerance +6.7%), leakage rate 2×10⁻ 5 .

[0098] Conclusion: Applying a pressure of 150 kN for 5 seconds eliminates stress and ensures dimensional accuracy and airtightness.

[0099] 4. Synergistic effect of composite coatings

[0100] Example 1: Imitation gold coating (2.1 μm) + molybdate sealing, salt spray life 1200 h.

[0101] Example 8: Absence of Si results in coating adhesion grade 1B and peeling after 240 h.

[0102] Conclusion: Pre-plated nickel and imitation gold electroplating form a dense protective layer, and combined with sealing treatment, the corrosion resistance life is extended.

[0103] This solution realizes the synergistic improvement of airtightness, corrosion resistance, and mechanical properties through innovative processes such as Si microalloying, low-oxygen annealing, and hydraulic shaping.

[0104] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. A method for manufacturing a high-airtight sealing stack ring, characterized in that: The composition of the sealing stack ring is as follows by mass percentage: Cu 64-68%, Si 0.3-0.6%, Zn balance, impurity Pb≤0.02%, impurity Fe≤0.1%; The manufacturing method of the high-airtightness sealing stack ring comprises the following steps: S100, select H65 brass plate, and verify through a spectrometer that the Si content of the H65 brass plate accounts for 0.3-0.6% of the total mass of the sealing stack ring; S200, annealing the H65 brass sheet verified in step S100 using a nitrogen protection annealing device, then soaking the H65 brass sheet in alkaline degreasing liquid using an ultrasonic cleaning device, and then washing and drying the sheet; S300, using a fiber laser cutting device to cut the H65 brass plate processed in step S200, using a CCD visual positioning system to calibrate the plate position, the outer diameter after cutting is Φ50±0.05mm, the inner diameter is Φ44±0.05mm, and a vibration grinder is used to remove the burrs on the cutting edge, Ra≤1.6μm; S400, using a progressive die to stamp the plate after the burrs are removed in step S300, wherein the progressive die stamping includes three stages: punching, pre-bending, and final bending, wherein the upper die R angle is 0.6 mm, the pressure is 80 kN, the bending angle is 30±1° during pre-bending, the compensation angle is 88°, the pressure is 120 kN, the rebound compensation amount is 2°, and the step difference is 1.8±0.03 mm during final bending, and finally a ring body is obtained; S500, using an aging furnace to keep the ring body obtained in step S400 warm, and then cooling it to room temperature by air; S600, cutting the sealing surface by CNC precision machining, pre-nickel-plating the cut ring body, and then performing imitation gold electroplating and sealing treatment to obtain a sealing stacked ring; The step S400 also includes hydraulic shaping of the ring body. During the hydraulic shaping, the pressure needs to be maintained for 5 seconds to eliminate local stress and ensure that the thickness reduction rate of the bending area is ≤15%.

2. The method for manufacturing a high-airtight sealing stack ring according to claim 1, characterized in that: In the step S200, the oxygen content in the nitrogen protection annealing device should be ≤50ppm, and the temperature should be kept at 450°C for 30 minutes. When the temperature in the device drops to 200°C, it is cooled to room temperature by air; The alkaline degreasing solution includes NaOH and Na2CO3, wherein the content of NaOH is 50 g / L and the content of Na2CO3 is 30 g / L. The H65 brass plate is immersed in the alkaline degreasing solution at 60° C. for 5 minutes.

3. The method for manufacturing a high-airtight sealing stack ring according to claim 2, characterized in that: The medium used in the vibration grinder in step S300 is ceramic balls.

4. The method for manufacturing a high-airtight sealing stack ring according to claim 3, characterized in that: The CNC machine tool spindle speed for cutting in step S600 is 1500 rpm, the feed rate is 0.1 mm / r, and the cutting depth is 0.05 mm; During pre-nickel plating, the ring body is pre-plated with a Watt nickel solution, wherein the neutral value of the Watt nickel solution is pH 4.0, the temperature is 55° C., the cathode moving speed during pre-nickel plating is 2 m / min, the current density is 3 A / dm²×5 min, and the plating thickness is 3±0.5 μm; The composition of the gold-imitation electroplating solution is 35g / L CuCN, 10g / L ZnO, 8g / L Na2SnO3, pH value is 12.5, the temperature of the plating solution is 55°C, the cathode current density is 1.5A / dm²×90s, and the coating thickness is 2±0.3μm.

5. The method for manufacturing a high-airtight sealing stack ring according to claim 4, characterized in that: After the imitation gold plating is completed, the sealing stack ring is immersed in a molybdate solution for 60 seconds and then dried by hot air at 80° C. to increase the corrosion resistance of the sealing stack ring.

6. A sealing stack ring, characterized in that: The sealing stack ring is manufactured by the manufacturing method of the high-airtightness sealing stack ring described in any one of claims 1-5, and the sealing stack ring includes a tail portion, a bending portion and a head portion, the end of the head portion is provided with a first notch, the end of the tail portion is provided with a second notch, and the first notch and the second notch are both arranged toward the bending portion.

7. The sealing stack ring according to claim 6, characterized in that: The head portion is arranged on one side of the bending portion, and the tail portion is arranged on the other side of the bending portion.

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