A method for manufacturing a stainless steel pipe joint sealing structure

Abstract

The application discloses a manufacturing method of a stainless steel pipe joint sealing structure, and the stainless steel pipe joint sealing structure manufactured through the method is specifically composed of three parts, namely, a clamping buckle with an inner thread arranged at a right end and a flange ring arranged at a left end, a moving joint with a matched outer thread structure arranged at an outer circle of a middle part and a first sealing end arranged at a left end, and a stationary joint with a matched flange structure arranged at an outer circle of a middle part and a second sealing end matched with the first sealing end of the moving joint arranged at a right end; the first sealing end of the moving joint is in a eccentric arc structure in a cross section; and the second sealing end matched with the first sealing end of the stationary joint is in a taper surface structure with an included angle of 15-35 degrees with an axis. The application has high reliability, good sealing performance, wide applicability, high vibration resistance, self-locking and no self-adhesion.

Description

Technical Field

[0001] This invention relates to a manufacturing technology for high-precision mechanical structures, and more particularly to a manufacturing method for a stainless steel pipe joint sealing structure. Background Technology

[0002] Pipe fittings are connecting tools between pipes, serving as detachable connection points between components and pipes. They play an indispensable role in pipe fittings and are one of the two main components of hydraulic pipelines. Pipe fittings offer both socket welding and threaded connections, used in areas requiring frequent assembly and disassembly, or for final adjustments to pipeline systems. Sealing is preferred for pipe fitting connections, typically used in systems transporting water, oil, and air. Common pipe fitting sealing methods include threaded seals, conical seals, and end-face seals.

[0003] In the aerospace field, pipe fittings are primarily used in high-temperature, high-pressure, and high-vibration hydraulic environments. This places high, even stringent, requirements on the structure, materials, and processing methods of pipe fittings, especially the connection parts. Currently, there are no specialized treatment methods for metal pipe fittings that can effectively cope with high-temperature, high-pressure, and high-vibration hydraulic environments. Most only offer threaded sealing connections, which severely limits flexibility and applicability. Furthermore, the sealant is prone to aging in high-temperature, high-pressure oil environments, creating unnecessary safety hazards and resulting in low reliability.

[0004] In this field, the most commonly used technologies for sealing joints are conical-to-conical sealing, conical-to-spherical sealing, and spherical-to-spherical sealing. Each has its own drawbacks and none can cope with the complex hydraulic working environment of high temperature, high pressure, and high vibration.

[0005] Therefore, there is a need for a stainless steel pipe joint sealing structure and its manufacturing method that is highly reliable, has good sealing performance, wide applicability, can withstand high vibration environments, is self-locking, and does not self-adhede. Summary of the Invention

[0006] The present invention aims to provide a stainless steel pipe joint sealing structure and its manufacturing method that features high reliability, good sealing performance, wide applicability, resistance to high vibration environments, self-locking, and non-self-adhesion.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a stainless steel pipe joint sealing structure, characterized in that: the stainless steel pipe joint sealing structure is specifically composed of three parts, namely, a clamping buckle with an internal thread on the right end and a flange on the left end, a moving joint with an external thread structure matching the internal thread of the clamping buckle on the outer circle in the middle and the left end being the first sealing end, and a stationary joint with a flange structure matching the first sealing end of the moving joint on the second sealing end on the right end and the flange on the outer circle in the middle matching the flange of the clamping buckle.

[0008] The first sealing end of the moving joint has a cross-sectional profile of an eccentric circular arc structure with an eccentric dimension of H and a radius of R. H and the outer diameter φC and radius R of the moving joint conform to the following formulas: ①R=(1.1~1.6)C;②C+1.8H=(1.8~1.9)R;

[0009] The cross-section of the second sealing end of the stationary joint, which matches the first sealing end, is a conical surface with an angle of 15° to 35° with the axis.

[0010] The manufacturing method of the above-mentioned stainless steel pipe joint sealing structure includes the following stages:

[0011] S1: Raw Material Preparation

[0012] ① Workpiece to be processed: Prepare a moving joint with an external thread structure that matches the internal thread of the clamping buckle on the outer circle of the middle and the first sealing end on the left; prepare a stationary joint with a flange structure that matches the first sealing end of the moving joint on the second sealing end on the right and the flange structure that matches the flange clamping buckle on the outer circle of the middle.

[0013] ② Raw materials and equipment for processing: Prepare a PVD coating machine with an internal working chamber, rotating working frame, vacuum pump, and water cooling system; a splicing target of molybdenum, vanadium, and copper with each element having a purity of not less than 99.9%; a chromium target with a purity of not less than 99.9%; a 600W ultraviolet light source; sufficient nitrogen; sufficient boron phosphide; sufficient γ-methacryloyloxypropyltrimethoxysilane; sufficient betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid inner salt; sufficient benzophenone; and sufficient ethanol.

[0014] S2: Surface treatment of eccentric arc structure

[0015] ① First, sandblasting is used to remove the passivation layer on the stainless steel surface to obtain a surface-activated motion joint;

[0016] ② The eccentric arc surface of the eccentric arc structure is protected by wax sealing, and the remaining parts are electroplated with copper with a thickness of 0.12mm to 0.18mm to obtain copper-plated protection for the moving joint.

[0017] ③ Wash away the wax layer with hot water, and then use sandblasting to activate the eccentric arc surface under the wax layer to obtain the activated motion joint;

[0018] ④ Place the activated motion joint obtained in step ③ into the PVD coating machine prepared in step ② of stage S1, and place it on the working rotating frame, ensuring that the eccentric arc surface is always facing the splicing target and maintaining a distance of 105cm to 110cm from the splicing target; then adjust the rotation speed of the working rotating frame to 4rpm to 6rpm, and then evacuate the furnace to 1×10 -3Pa~2×10 -3 Pa;

[0019] ⑤ Introduce nitrogen into the furnace, adjust the nitrogen pressure inside the furnace to 0.7Pa~0.8Pa, raise the temperature to 195℃~210℃, then apply a bias voltage of -130V~-150V to the activated moving joint, then turn on the chromium target, set the target current to 85A~95A, and deposit a CrN transition layer for 8min~10min to reduce the residual stress of the coating and improve the adhesion.

[0020] ⑥ Control the nitrogen pressure to shut off the chromium target, open the splicing target, and then turn on the high-power pulsed magnetron splicing power supply. Set the splicing target power to 1.1 kW to 1.2 kW, the duty cycle to 6.5% to 8%, and the deposition time to 150 min to 170 min to complete the coating and obtain the coated moving joint. Then turn off the target power supply and the bias power supply, and close the gas flow valve. After the temperature of the coated moving joint cools down to room temperature with the furnace, the furnace door can be opened to remove the coated moving joint, thus completing the coating process and obtaining the coated moving joint.

[0021] ⑦ The coated motion joint is subjected to electroplating copper stripping treatment, and then heated to 200℃~220℃ to remove hydrogen for 8h~10h to obtain the finished motion joint;

[0022] S3: Surface treatment of the conical surface

[0023] ①The conical surface of the stationary joint is directly irradiated with ultraviolet light for 12 to 15 minutes to obtain an irradiated stationary joint;

[0024] ②Then the irradiated static connector is completely immersed in an ethanol solution of 2wt% γ-methacryloyloxypropyltrimethoxysilane and left to stand for 13h to 15h. After the treatment is completed, the product is taken out and repeatedly washed with ethanol and deionized water, and then vacuum dried at 60℃ to 65℃ for 3.5h to 4h.

[0025] ③ Prepare a boron phosphide ethanol solution with a mass concentration of 11 g / L to 13 g / L, immerse the product obtained in step ② completely in it for 50 to 60 seconds, and then take out the product and wash it off with ethanol.

[0026] ④ Immerse the product in a betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid internal salt aqueous solution with a mass concentration of 5 g / L to 8 g / L, cover it with filter paper to limit the wavelength of ultraviolet light passing through to 320 nm to 380 nm, and irradiate it under an ultraviolet light source for 15 min to 18 min to induce a polymerization reaction. Remove the product, then repeatedly clean it with ethanol and deionized water and dry it to obtain the desired finished static joint.

[0027] Compared with the prior art, the present invention has the following advantages due to the adoption of the above technical solutions:

[0028] (1) The present invention, by setting a three-in-one self-locking structure of clamping buckle, stationary joint, and moving joint, is actually an adjustment based on existing mature technology. In specific use, the general three-in-one self-locking structure of clamping buckle, stationary joint, and moving joint cannot adapt to the complex high temperature, high pressure, and high vibration hydraulic working environment specifically addressed by the present invention. The special improvement of the present invention is that: firstly, the spherical surface is changed to a spherical surface, and the angle of the corresponding sealing cone surface is limited. In the preferred technology, the spherical degree is also specifically limited. All of this is to achieve a more stable seal while obtaining the optimal stress structure. Figures 2-5 As can be seen from the simulation diagram, the sealing surface of the present invention bears the highest pressure, while the pressure at the point of maximum stress is the lowest. This is the optimal combination of sealing performance and reliability, indicating that the structure of the present invention can effectively reduce the risk of oil leakage and seepage, while improving the reliability and maintainability of the joint.

[0029] (2) The preferred method of treating the sealing structure of the stationary joint and the moving joint in this invention can further enhance the sealing performance, reliability and durability of the joint. The moving end is treated with surface hardening and self-lubrication (molybdenum-vanadium-copper composite chromium-nitrogen five-element co-diffusion, in which chromium and nitrogen are deposited first to strengthen the film bonding force, molybdenum-vanadium is used to strengthen the relatively soft stainless steel substrate surface, and copper is used for surface adaptive deformation and lubrication). The stationary end is treated with softening corrosion-resistant surface sealing (strengthening surface integrity). First, ultraviolet rays are used to irradiate the stainless steel without affecting its inherent corrosion resistance, and micro-cavities are artificially created on the passivation film formed on the stainless steel surface. Then, light curing technology is used to fill (actually, it is activated and grafted, with better bonding force) corrosion-resistant flexible organic molecules. In this way, the two sealing end faces can achieve better soft and hard matching. First, it can achieve more complete contact of the sealing surface through adaptive deformation and self-lubrication. Second, it can prevent self-adhesion on both sides of the sealing end faces due to the same material. Third, it can better adapt to high vibration environment.

[0030] Therefore, the present invention has the characteristics of high reliability, good sealing performance, wide applicability, resistance to high vibration environment, self-locking and non-self-adhesiveness. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure 2 This is a comparison diagram of stress coordinates between the present invention and negative and positive controls;

[0033] Figure 3 Stress simulation diagram of the negative control product for matching the cone surface;

[0034] Figure 4This is a stress simulation diagram of the conical surface matching the rotating eccentric circular arc surface of the present invention;

[0035] Figure 5 Stress simulation diagram of a positive control product with added grooves based on the present invention;

[0036] Figure 6 This is a comparison table of indicators between the present invention and negative and positive controls;

[0037] Figure 7 This is a schematic diagram of the splicing target structure;

[0038] Figure 8 The preferred surface morphology of the membrane layer after the sealing surface treatment of the motion joint in this invention;

[0039] Figure 9 The preferred surface morphology of the film layer after the static joint sealing surface treatment of the present invention;

[0040] Figure 10 This is a physical image of the performance testing equipment of the present invention;

[0041] Figure 11 This is a schematic diagram of the structure of the motion connector of the present invention.

[0042] In the diagram: 1. Hoop fastener; 2. Stationary joint; 3. Moving joint; 4. Splicing target. Detailed Implementation Example 1

[0043] like Figure 1 The stainless steel pipe joint sealing structure shown is composed of three parts: a clamping buckle 1 with an internal thread on the right end and a flange on the left end; a moving joint 3 with an external thread structure matching the internal thread of the clamping buckle on the outer circle in the middle and the left end being the first sealing end; and a stationary joint 2 with a flange structure matching the first sealing end of the moving joint 3 and the flange on the outer circle in the middle matching the flange of the clamping buckle 1.

[0044] The first sealing end of the motion connector 3 has a cross-sectional profile of an eccentric circular arc structure with an eccentric dimension of H and a radius of R. H and the outer diameter φC and radius R of the motion connector 3 conform to the following formulas: ①R=(1.1~1.6)C;②C+1.8H=(1.8~1.9)R;

[0045] The second sealing end of the stationary joint 2, which matches the first sealing end, has a conical cross-section that forms an angle of 15° to 35° with the axis.

[0046] The manufacturing method of the above-mentioned stainless steel pipe joint sealing structure includes the following stages:

[0047] S1: Raw Material Preparation

[0048] ① Workpiece to be processed: Prepare a moving joint 3 with an external thread structure that matches the internal thread of the clamping buckle on the outer circle of the middle and the first sealing end on the left; prepare a stationary joint 2 with a flange structure that matches the first sealing end of the moving joint 3 on the second sealing end on the right and the flange structure that matches the flange of the clamping buckle 1 on the outer circle of the middle.

[0049] ② Raw materials and equipment for processing: Prepare a PVD coating machine with an internal working chamber, working rotating frame, vacuum pump, and water cooling system; a splicing target 4 of molybdenum-vanadium-copper with each element having a purity of not less than 99.9%; a chromium target with a purity of not less than 99.9%; a 600W ultraviolet light source; sufficient nitrogen; sufficient boron phosphide; sufficient γ-methacryloyloxypropyltrimethoxysilane; sufficient betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid inner salt; sufficient benzophenone; and sufficient ethanol.

[0050] S2: Surface treatment of eccentric arc structure

[0051] ① First, sandblasting is used to remove the passivation layer on the stainless steel surface to obtain the surface-activated motion joint 3;

[0052] ② The eccentric arc surface of the eccentric arc structure is protected by wax sealing, and copper is electroplated on the remaining parts. The thickness of the electroplated copper layer is 0.12mm to 0.18mm, thus obtaining copper-plated protective moving joint 3;

[0053] ③ The wax layer is washed away with hot water, and the eccentric arc surface under the wax layer is activated by sandblasting again to obtain the activated motion joint 3;

[0054] ④ Place the activated motion connector 3 obtained in step ③ into the PVD coating machine prepared in step ② of stage S1, and place it on the working rotating frame, so that the eccentric arc surface is always facing the splicing target 4, and the distance between the eccentric arc surface and the splicing target 4 is 105cm to 110cm; then adjust the rotation speed of the working rotating frame to 4rpm to 6rpm, and then evacuate the furnace to 1×10 -3 Pa~2×10 -3 Pa;

[0055] ⑤ Introduce nitrogen into the furnace, adjust the nitrogen pressure inside the furnace to 0.7Pa~0.8Pa, raise the temperature to 195℃~210℃, then apply a bias voltage of -130V~-150V to the activated motion connector 3, then turn on the chromium target, set the target current to 85A~95A, and deposit a CrN transition layer for 8min~10min to reduce the residual stress of the coating and improve the adhesion.

[0056] ⑥ Control the nitrogen pressure to shut off the chromium target, open the splicing target 4, and then turn on the high-power pulsed magnetron splicing power supply. Set the power of the splicing target 4 to 1.1 kW to 1.2 kW, the duty cycle to 6.5% to 8%, and the deposition time to 150 min to 170 min to complete the coating and obtain the coated moving joint 3. Then turn off the target power supply and the bias power supply, and close the gas flow valve. After the temperature of the coated moving joint 3 cools down to room temperature with the furnace, the furnace door can be opened to remove the coated moving joint 3, thus completing the coating process and obtaining the coated moving joint 3.

[0057] ⑦ The coated motion connector 3 is subjected to electroplating copper removal treatment, and then heated to 200℃~220℃ to remove hydrogen for 8h~10h to obtain the finished motion connector 3;

[0058] S3: Surface treatment of the conical surface

[0059] ①The conical surface of the stationary joint 2 is directly irradiated with ultraviolet light for 12 to 15 minutes to obtain the irradiated stationary joint 2;

[0060] ②Then the irradiated static connector 2 is completely immersed in an ethanol solution of 2wt% γ-methacryloyloxypropyltrimethoxysilane and left to stand for 13h to 15h. After the treatment is completed, the product is taken out and repeatedly washed with ethanol and deionized water, and then vacuum dried at 60℃ to 65℃ for 3.5h to 4h.

[0061] ③ Prepare a boron phosphide ethanol solution with a mass concentration of 11 g / L to 13 g / L, immerse the product obtained in step ② completely in it for 50 to 60 seconds, and then take out the product and wash it off with ethanol.

[0062] ④ Immerse the product in a betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid internal salt aqueous solution with a mass concentration of 5 g / L to 8 g / L, cover with filter paper to limit the wavelength of ultraviolet light passing through to 320 nm to 380 nm, and irradiate under an ultraviolet light source for 15 min to 18 min to induce a polymerization reaction. Remove the product, then repeatedly clean it with ethanol and deionized water and dry it to obtain the desired finished static connector 2.

[0063] The mechanical simulation diagram of the pipe joint sealing structure manufactured according to this embodiment is as follows. Figure 4 As shown, it is compared with the negative control (such as...) Figure 3 As shown), positive control (e.g.) Figure 5 The control indicators are shown below. Figure 2 and Figure 6 As shown, the surface morphology of the sealing surface of the moving joint 2 is as follows: Figure 8 As shown, the surface morphology of the sealing surface of the stationary joint 2 is as follows: Figure 9 As shown, the specific detection method in this embodiment is as follows: Figure 10 The equipment shown was tested, and the indicators are as follows:

[0064] 1. Connection Strength Test: While maintaining the design working pressure, a tensile test is performed on the specimen. Force is applied at a rate of (4 + 0.3) mm / min until leakage, pull-out, or fracture occurs. The tensile force values ​​at leakage, pull-out, or fracture are recorded respectively. The conduit must not rupture or be pulled out of the joint before reaching the axial tensile force (2918.14 N) formed by 4 times the design working pressure. This means that this embodiment can withstand the axial tensile force formed by a working pressure of 2918.14 N. Test conditions: Installation torque 15 Nm; Test medium: No. 10 aviation hydraulic oil; Test pressure 48 MPa; Tensile rate 4 mm / min.

[0065] Test results: The tensile load when the specimen showed deformation and fracture was 3060N.

[0066] 2. Thermal Shock Test Requirements: Pressurize the specimen to the design working pressure, raise the test chamber temperature to the highest working temperature and maintain it for 2 hours, then discharge the test medium. Within 20 seconds, replace the test medium with the lowest working temperature medium, and within another 20 seconds, pressurize to twice the design working pressure, hold the pressure for 1 minute, and the specimen should show no leakage. Then release the pressure for 1 minute. Cold Test Chamber Test: After cooling to room temperature, repressurize to the design working pressure, cool to the lowest working temperature and maintain it for 2 hours, then discharge the test medium. Within 20 seconds, replace the test medium with the highest working temperature medium, and within another 20 seconds, pressurize to twice the design working pressure, hold the pressure for 1 minute, and the specimen should show no leakage. Repeat the above sequence 3 times. During the test, the specimen should show no leakage. Test conditions: Specimen installation torque 15 Nm, test medium No. 10 aviation hydraulic oil, test pressure 48 MPa; test temperature +150℃; after holding for 2 hours, drain the test medium; then replace with a cryogenic liquid, controlling the liquid temperature at -55℃, with a liquid replacement time of less than 20 seconds; then pressurize to 96 MPa, with a pressurization time of less than 20 seconds; hold the pressure for 1 minute; if no leakage is observed, finally release the pressure for less than 1 minute; then perform a reverse circulation: pressurize to 48 MPa; cool to -55℃; hold for 2 hours, then drain the test medium; replace with a high-temperature liquid, with a liquid temperature of +150℃, with a liquid replacement time of less than 20 seconds; then pressurize to 96 MPa, with a pressurization time of less than 20 seconds, and hold the pressure for 1 minute. Repeat the above sequence 3 times (the required pass rate is 3 times, but to verify the technical effect, this invention is consistently tested 5 times).

[0067] Test results: No leakage was observed during the 5-cycle test. Example 2

[0068] The overall structure is consistent with Example 1, except that:

[0069] No special treatment is required for the sealing surface of the stationary joint 2.

[0070] The pipe joint sealing structure manufactured in this embodiment has a tensile load of 3095N when the specimen deforms and breaks during the connection strength test, which is better than that of Embodiment 1; however, it can only withstand 4 cycles during the thermal shock test, and a total of 50 drops of leakage occurs on the 5th cycle, which is worse than that of Embodiment 1. Example 3

[0071] The overall structure is consistent with Example 1, except that:

[0072] No special treatment is required for the sealing surface of the motion joint 3.

[0073] The pipe joint sealing structure manufactured in this embodiment has a tensile load of 3072N when the specimen deforms and breaks during the connection strength test, which is better than that of Embodiment 1; however, it can only withstand 4 cycles during the thermal shock test, and a total of 78 drops of leakage occurs in the 5th cycle, which is worse than that of Embodiment 1. Example 4

[0074] The overall structure is consistent with Example 1, except that:

[0075] No special treatment is applied to the sealing surfaces of stationary joint 2 and moving joint 3.

[0076] The pipe joint sealing structure manufactured in this embodiment has a tensile load of 3112N when the specimen deforms and breaks during the connection strength test, which is better than that of Embodiments 1 to 3; however, it can only withstand 3 cycles during the thermal shock test, and a total of 210 drops of leakage occurs in the 4th and 5th cycles, which is worse than that of Embodiment 1.

[0077] In summary, considering the actual working environment and operating conditions required for the present invention, Example 1 is the optimal embodiment; Example 4 is the most resistant to pull-out and is suitable for operating conditions where pull-out resistance is emphasized.

[0078] The above description of the disclosed embodiments is merely intended to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing a stainless steel pipe joint sealing structure, characterized in that: The stainless steel pipe joint sealing structure manufactured by this method consists of three parts: a clamping buckle (1) with an internal thread on the right end and a flange on the left end; a moving joint (3) with an external thread structure matching the internal thread of the clamping buckle and a first sealing end on the left end; and a stationary joint (2) with a flange structure matching the flange of the clamping buckle (1) and a second sealing end on the right end matching the first sealing end of the moving joint (3) and a flange structure matching the flange of the clamping buckle (1) on the outer circle in the middle. The first sealing end of the motion connector (3) has a cross-sectional profile of an eccentric circular arc structure with an eccentric dimension of H and a radius of R. H and the outer diameter φC and radius R of the motion connector (3) conform to the following formulas: ①R=(1.1~1.6)C;②C+1.8H=(1.8~1.9)R; The cross-section of the second sealing end of the stationary joint (2) that matches the first sealing end is a conical surface with an angle of 15° to 35° with the axis; The manufacturing method of the above-mentioned stainless steel pipe joint sealing structure includes the following stages: S1: Raw Material Preparation ① Workpiece to be processed: Prepare a motion joint (3) with an external thread structure that matches the internal thread of the clamping buckle on the middle outer circle and the first sealing end on the left; prepare a stationary joint (2) with a flange structure that matches the first sealing end of the motion joint (3) on the right second sealing end and the flange structure that matches the clamping buckle (1) on the middle outer circle. ② Raw materials and equipment for processing: Prepare a PVD coating machine with an internal working chamber, working rotating frame, vacuum pump and water cooling system, a splicing target of three pure metals (molybdenum-vanadium-copper) with a purity of not less than 99.9% for each element, a chromium target with a purity of not less than 99.9%, a UV light source with a rated power of 600W, sufficient nitrogen, sufficient boron phosphide, sufficient γ-methacryloyloxypropyltrimethoxysilane, sufficient betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid inner salt, sufficient benzophenone, and sufficient ethanol; S2: Surface treatment of eccentric arc structure ① First, sandblasting is used to remove the passivation layer on the stainless steel surface to obtain a surface-activated motion joint (3); ② The eccentric arc surface of the eccentric arc structure is protected by wax sealing, and copper is electroplated on the remaining parts. The thickness of the electroplated copper layer is 0.12mm~0.18mm, and copper-plated protective moving joint is obtained (3); ③ The wax layer is washed away with hot water, and the eccentric arc surface under the wax layer is activated by sandblasting again to obtain the activated motion joint (3); ④ Place the activated motion joint (3) obtained in step ③ into the PVD coating machine prepared in step ② of stage S1, and place it on the working rotating frame, so that the eccentric arc surface is always facing the splicing target (4) and the distance between it and the splicing target (4) is 105cm to 110cm; then adjust the rotation speed of the working rotating frame to 4rpm to 6rpm, and then evacuate the furnace to 1×10 -3 Pa~2×10 -3 Pa; ⑤ Introduce nitrogen into the furnace, adjust the nitrogen pressure in the furnace to 0.7Pa~0.8Pa, raise the temperature to 195℃~210℃, then apply a bias voltage of -130V~-150V to the activated motion connector (3), then open the chromium target, set the target current to 85A~95A, and deposit a CrN transition layer for 8min~10min to reduce the residual stress of the coating and improve the adhesion. ⑥ Control the nitrogen pressure to close the chromium target, open the splicing target (4), then turn on the high-power pulsed magnetron splicing power supply, set the splicing target (4) power to 1.1kw~1.2kw, duty cycle to 6.5%~8%, and deposition time to 150min~170min, complete the coating, and obtain the coating motion joint (3); then turn off the target power supply and bias power supply, close the gas flow valve, and after the temperature of the coating motion joint (3) cools down to room temperature with the furnace, open the furnace door to take out the coating motion joint (3), complete the coating process, and obtain the coating motion joint (3); ⑦ The coated motion connector (3) is subjected to electroplating copper removal treatment, and then heated to 200℃~220℃ to remove hydrogen for 8h~10h to obtain the finished motion connector (3); S3: Surface treatment of the conical surface ①The conical surface of the stationary joint (2) was directly irradiated with ultraviolet light source for 12 min to 15 min to obtain the irradiated stationary joint (2); ②Then the irradiated static connector (2) was completely immersed in an ethanol solution of 2wt% γ-methacryloyloxypropyltrimethoxysilane and left to stand for 13h to 15h. After the treatment was completed, the product was taken out and repeatedly washed with ethanol and deionized water. Then it was vacuum dried at 60℃ to 65℃ for 3.5h to 4h. ③ Prepare a boron phosphide ethanol solution with a mass concentration of 11 g / L to 13 g / L, immerse the product obtained in step ② completely in it for 50 to 60 seconds, and then take out the product and wash it off with ethanol. ④The product is then immersed in a betaine-type N,N-dimethyl-N-methacrylamidopropyl-N-propanesulfonic acid internal salt aqueous solution with a mass concentration of 5g / L~8g / L, covered with filter paper to limit the wavelength of ultraviolet light passing through to 320nm~380nm, and irradiated under an ultraviolet light source for 15min~18min to induce a polymerization reaction. The product is then removed, and repeatedly cleaned with ethanol and deionized water and dried to obtain the desired finished static connector (2).

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