High-strength wear-resistant bolt and preparation process thereof

Abstract

The application discloses a high-strength wear-resistant bolt and a preparation process thereof, and relates to the technical field of bolt preparation. The preparation process comprises the following steps: after the bolt body to be machined is cleaned, dried, annealed, cleaned again and dried, the bolt body to be machined is subjected to chemical pickling by an acid pickling device for multiple times; the bolt body to be machined is placed into a multi-station automatic cold header, and a blank is prepared after the bolt body to be machined is subjected to stamping, upsetting, extrusion and diameter reduction processing; the blank is subjected to rolling by a rolling die to process a semi-finished bolt body with a threaded portion on the surface of the blank; and finally, the bolt body is obtained by quenching, tempering, polishing and electroplating. The high-strength wear-resistant bolt is prepared by coating a ceramic reinforced composite coating on the threaded portion. The application can guarantee the stable quality of the high-strength wear-resistant bolt.

Description

Technical Field

[0001] This invention relates to the field of bolt manufacturing technology, specifically to a high-strength wear-resistant bolt and its manufacturing process. Background Technology

[0002] Bolt manufacturing is a precision machining process. First, high-quality steel is selected and cold-forged or hot-forged into a blank to give the material a preliminary bolt shape and enhance its internal density. Next, machining processes such as turning and milling are performed to precisely control the thread size and shape. Following this, heat treatment is carried out through quenching and tempering to improve strength and toughness. Some bolts also require surface treatment, such as galvanizing for rust prevention. Finally, rigorous inspection is conducted to check dimensional accuracy, mechanical properties, etc., ensuring that each bolt meets standards and can be used reliably in various fields.

[0003] The manufacturing process of bolts determines their quality. For example, the high-strength corrosion-resistant bolt manufacturing process disclosed in patent publication number CN117737611A involves repeatedly cold-forging alloy steel to achieve a uniform microstructure. Then, isothermal spheroidizing annealing further refines the alloy steel's microstructure, effectively improving its toughness and preventing the bolt from becoming too brittle due to increased hardness. Simultaneously, carbonitriding is used to create a hard but not brittle diffusion layer on the bolt surface, resulting in high wear resistance, anti-galling, and anti-scratch properties. During carbonitriding, cooling oil is used to cool the semi-finished part, further increasing the diffusion layer depth and improving the overall wear resistance and fatigue strength of the bolt. The bolt's toughness is also guaranteed. Finally, electroplating forms a protective layer on the bolt surface, providing excellent corrosion resistance.

[0004] The manufacturing of bolts requires chemical pickling, in which the bolts are immersed in acid to remove surface oxides and other impurities. The existing manufacturing process only performs a single pickling, and the pickling solution needs to be replenished with acid every few pickling cycles. Within a single replenishment cycle, the concentration of the pickling solution before and after the cycles varies, which makes it difficult to guarantee the quality of the produced bolts. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength wear-resistant bolt and its manufacturing process to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A manufacturing process for high-strength wear-resistant bolts includes:

[0008] S1: Material selection: Select the bolt body to be processed, and clean and dry it;

[0009] S2: Annealing treatment: Heat the bolt body to be processed to 800℃~920℃ and hold for 30 minutes, then cool down to 680℃~700℃ and hold for 80 minutes, then cool down to 480℃~500℃ and air cool.

[0010] S3: Clean and dry the bolt body prepared in step S2 again, then heat it to 560℃~580℃, keep it at that temperature for 80min~90min and then cool it.

[0011] S4: Chemical pickling: The bolt body to be processed is chemically pickled multiple times using pickling equipment;

[0012] S5: Forming: The bolt body to be processed is placed in a multi-station automatic cold heading machine, and after being processed by stamping, forging, extrusion and diameter reduction, a blank is obtained. The blank is then rolled by a rolling die to process a semi-finished bolt body with threaded parts on its surface.

[0013] S6: Quenching: Quench the semi-finished bolt body at a quenching temperature of 850℃~900℃ for 28min~37min, and then quickly immerse it in a quenching oil bath for cooling.

[0014] S7: Tempering: Temper the quenched semi-finished bolt body at a temperature of 370℃~390℃ for 80min~120min, and then allow it to cool naturally.

[0015] S8: Grinding: Place the tempered semi-finished bolt body into a vibrating sand shot blasting machine to remove the burrs on the surface of the semi-finished bolt body using sand particles.

[0016] S9: Electroplating: The semi-finished bolt body after grinding is placed in an electroplating bath for electroplating treatment to obtain the finished bolt body.

[0017] S10: A ceramic-reinforced composite coating is plated on the outside of the threaded portion to obtain a high-strength wear-resistant bolt.

[0018] Preferably, the mesh size of the sand particles in step S8 is 400-800 mesh.

[0019] Preferably, the pickling equipment includes a base, an annular rotating groove rotatably disposed above the base, a plurality of pickling tanks of the same specifications disposed inside the annular rotating groove, a vertical hydraulic cylinder rotatably disposed in the middle of the base, a rotating ring fixed at the top of the vertical hydraulic cylinder, a plurality of material cylinders for placing the bolt bodies to be processed are disposed below the rotating ring, and the material cylinders are respectively aligned with the pickling tanks at corresponding positions, a plurality of small holes are opened on the side wall of the material cylinders to facilitate the entry and exit of pickling solution, and a driving mechanism is disposed on the base to drive the annular rotating groove and the vertical hydraulic cylinder to rotate.

[0020] Preferably, the driving mechanism includes a fixed ring fixed on the base, and an annular rotating groove sleeved on the outside of the fixed ring. A first driving motor is fixed on the fixed ring, and a driving gear is fixed on the output shaft of the first driving motor. An internal gear ring is fixed on the inner side of the annular rotating groove and meshes with the driving gear. A second driving motor is installed on the base, and a rotating disk is rotatably arranged at the middle position of the base. A vertical hydraulic cylinder is fixed on the rotating disk, and the output shaft of the second driving motor is connected to the rotating disk through a belt drive pair.

[0021] Preferably, a sliding sleeve is fixed at the middle position of the material cylinder, and a sliding rod is slidably arranged in the middle of the sliding sleeve. A quick-connect assembly is provided between the upper end of the sliding rod and the rotating ring. A feeding conveyor belt and a discharging conveyor belt are provided on the side end of the base, and an acid washing tank is spaced between the feeding conveyor belt and the discharging conveyor belt.

[0022] Preferably, the quick-connect assembly includes a sleeve fixed to the lower end of the rotating ring, an installation port is provided on the side wall of the sleeve, and a locking tongue is slidably provided in the installation port. An installation shell is fixed to the outside of the installation port, and a compression spring for pressing the locking tongue is provided in the installation shell. The end of the locking tongue is provided with a downward-facing first chamfer. A connector is provided at the upper end of the slide rod, and a clamp is fixed at the upper end of the connector. A lifting ring is slidably sleeved on the connector. The lifting ring is located below the clamp, and the upper edge of the clamp is provided with a second chamfer. The lower outer edge of the lifting ring is provided with a third chamfer, and the height of the feeding conveyor belt is lower than that of the discharging conveyor belt.

[0023] Preferably, the lower end of the material cylinder is fixed with several support feet, and the bottom of the support feet is rotatably provided with ball bearings.

[0024] Preferably, a support rod is fixed on the base, the support rod is located between the feed conveyor belt and the discharge conveyor belt, the upper end of the support rod is fixed with a feeding pipe for adding acid, a swing plate is rotatably installed on the feeding pipe, and a concentration sensor and a counterweight are installed at the lower end of the swing plate.

[0025] Based on the same inventive concept, a high-strength wear-resistant bolt is also proposed, comprising a bolt body prepared by the above-mentioned high-strength wear-resistant bolt manufacturing process, wherein the bolt body is provided with a threaded portion, and the threaded portion is coated with a ceramic-reinforced composite coating, wherein the ceramic-reinforced composite coating comprises the following components by weight percentage:

[0026] Alumina 35%-45%, particle size 1-3μm;

[0027] Silicon carbide 20%-30%, particle size 0.5-2μm;

[0028] Polytetrafluoroethylene 10%-15%;

[0029] Epoxy resin adhesive 15%-25%, curing shrinkage rate ≤2%;

[0030] Dispersant 0.5%-1.0%;

[0031] Defoamer 0.1%-0.3%;

[0032] The ceramic-reinforced composite coating has a thickness of 50-80 μm and is formed by a staged temperature-curing process, which includes: pre-drying at 80°C for 1 hour, preliminary cross-linking at 150°C for 2 hours, and complete curing at 200°C for 1 hour.

[0033] Preferably, in the ceramic-reinforced composite coating, the weight ratio of alumina to silicon carbide is 1.5:1 to 2:1, and the viscosity of the epoxy resin binder at 200°C is 500-1000 mPa·s.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] Through a rotating ring and an annular rotating trough equipped with multiple pickling tanks, as the rotating ring rotates, the material cylinder drives the bolt body to be processed to be pickled in each pickling tank in sequence. Moreover, acid is continuously replenished to the first pickling tank that comes into contact with the bolt body to be processed, so as to even out the decrease in acid concentration and prevent large differences in the bolt bodies to be processed at different times, thus ensuring the stability of the quality of the bolt bodies to be processed.

[0036] Simultaneously, the material cylinder containing the bolts to be processed is moved to the lower end of the rotating ring by the feeding conveyor belt. During pickling, the rotating ring descends, and under the action of the quick-connect assembly, the end of the sliding rod is connected to the lower part of the rotating ring, which can drive the sliding sleeve and the material cylinder to rise and detach from the feeding conveyor belt. Similarly, when the rotating ring descends, the material cylinder located above the discharge conveyor belt will be placed on the discharge conveyor belt, and the quick-connect assembly will then disconnect, thereby realizing automatic loading and unloading, improving the degree of automation, and increasing production efficiency. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of the pickling equipment in this invention;

[0038] Figure 2 This is a schematic diagram of the drive mechanism in this invention;

[0039] Figure 3 This is a schematic diagram of the external structure of the quick-connect component in this invention;

[0040] Figure 4 This is a schematic diagram of the internal structure of the quick-connect component in this invention;

[0041] Figure 5This is a schematic diagram of the material cylinder structure in this invention;

[0042] Figure 6 This is a schematic diagram of the feeding pipe in this invention;

[0043] Figure 7 This is a schematic diagram of the high-strength wear-resistant bolt of the present invention.

[0044] In the picture:

[0045] 1. Base; 2. Annular rotating groove; 3. Pickling tank; 4. Vertical hydraulic cylinder; 5. Rotating ring; 6. Material cylinder; 7. Fixed ring; 8. Internal gear ring; 9. First drive motor; 10. Drive gear; 11. Rotating disk; 12. Second drive motor; 13. Belt drive pair; 14. Sliding sleeve; 15. Sliding rod; 16. Feed conveyor belt; 17. Discharge conveyor belt; 18. Sleeve; 19. Connector; 20. Clamp; 21. Lifting ring; 22. Mounting port; 23. Locking tongue; 24. Mounting shell; 25. Compression spring; 26. Support foot; 27. Ball bearing; 28. Support rod; 29. ​​Feeding pipe; 30. Swing plate; 31. Concentration sensor; 32. Counterweight; 33. Bolt body; 34. Threaded part. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] like Figures 1-5 As shown, the present invention provides a technical solution: a manufacturing process for high-strength wear-resistant bolts, comprising:

[0048] S1: Material selection: Select the bolt body to be processed, and clean and dry it;

[0049] S2: Annealing treatment: Heat the bolt body to be processed to 800℃~920℃ and hold for 30 minutes, then cool down to 680℃~700℃ and hold for 80 minutes, then cool down to 480℃~500℃ and air cool.

[0050] S3: Clean and dry the bolt body prepared in step S2 again, then heat it to 560℃~580℃, keep it at that temperature for 80min~90min and then cool it.

[0051] S4: Chemical pickling: The bolt body to be processed is chemically pickled multiple times using pickling equipment;

[0052] S5: Forming: The bolt body to be processed is placed in a multi-station automatic cold heading machine, and after being processed by stamping, forging, extrusion and diameter reduction, a blank is obtained. The blank is then rolled by a rolling die to process a semi-finished bolt body with threaded part 34 on its surface.

[0053] S6: Quenching: Quench the semi-finished bolt body at a quenching temperature of 850℃~900℃ for 28min~37min, and then quickly immerse it in a quenching oil bath for cooling.

[0054] S7: Tempering: Temper the quenched semi-finished bolt body at a temperature of 370℃~390℃ for 80min~120min, and then allow it to cool naturally.

[0055] S8: Grinding: Place the tempered semi-finished bolt body into a vibrating sand shot blasting machine to remove the burrs on the surface of the semi-finished bolt body using sand particles.

[0056] S9: Electroplating: The semi-finished bolt body after grinding is placed in an electroplating bath for electroplating treatment to obtain the finished bolt body 33.

[0057] S10: A ceramic-reinforced composite coating (not shown in the figure) is plated on the outside of the threaded portion 34 to obtain a high-strength wear-resistant bolt.

[0058] It should be noted that the following pickling equipment was used in this embodiment. It has multiple pickling tanks and can pickle the bolt body to be processed multiple times with different concentrations. This makes it easy to control the pickling progress, thereby eliminating the micro-unevenness on the surface of the bolt body to be processed. This provides a uniform substrate for subsequent surface treatments such as phosphating and electroplating, improves the coating adhesion, and thus improves the strength and wear resistance of the bolt body to be processed.

[0059] In step S8, the mesh size of the sand particles is 400-800 mesh.

[0060] It should be noted that this grit size can remove small imperfections and burrs, making the surface of the bolt body gradually uniform.

[0061] like Figure 1As shown, the pickling equipment includes a base 1, an annular rotating groove 2 rotatably mounted on the top of the base 1, several pickling tanks 3 of the same specifications are arranged inside the annular rotating groove 2, a vertical hydraulic cylinder 4 is rotatably mounted in the middle of the base 1, a rotating ring 5 is fixed at the top of the vertical hydraulic cylinder 4, several material cylinders 6 are arranged at equal intervals below the rotating ring 5 for placing the bolt bodies to be processed, and the material cylinders 6 are respectively aligned with the pickling tanks 3 at corresponding positions. Several small holes (not marked in the figure) are opened on the side wall of the material cylinders 6 to facilitate the entry and exit of pickling solution, and a driving mechanism is provided on the base 1 to drive the annular rotating groove 2 and the vertical hydraulic cylinder 4 to rotate.

[0062] It is important to note that during pickling, the bolt body to be processed is placed into the material cylinder 6 from one position. Then, the drive mechanism rotates the vertical hydraulic cylinder 4 by a certain angle, causing the material cylinder 6 to move the distance of one pickling tank 3 and align with the adjacent pickling tank 3. Then, the vertical hydraulic cylinder 4 drives the rotating ring 5 to descend, placing the material cylinder 6 into the lower pickling tank 3 for pickling. At this point, the operator can place the bolt body back into the original position. This process is repeated. As the rotating ring 5 rotates, after the material cylinder 6 has carried the bolt body to be processed through each pickling tank 3 in sequence, it can be removed from another position. Pickling can be repeated multiple times, and as pickling continues, the bolt body will gradually improve in quality. The acid concentration drops the most in the pickling tank 3 that first contacts the bolt body to be processed. Therefore, an acid pickling tank 3 is left empty between the loading and unloading to replenish acid (increase the acid concentration). When the concentration of the acid pickling tank 3 that first contacts the bolt body to be processed is lower than the set value, the drive mechanism drives the annular rotating groove 2 to rotate in the opposite direction by a certain angle to replenish acid in the first acid pickling tank 3. At the same time, the acid pickling tank 3 that has just been replenished is moved to the last pickling position. This process is repeated to replenish acid in each acid pickling tank 3, ensuring the concentration stability of each acid pickling tank 3 during the pickling process, distributing the decrease in acid concentration evenly, preventing large differences in the quality of the bolt body to be processed when pickled at different times, and ensuring the stability of the quality of the bolt body to be processed.

[0063] like Figure 2 As shown, the drive mechanism includes a fixed ring 7 fixed on the base 1, and an annular rotating groove 2 sleeved on the outside of the fixed ring 7. A first drive motor 9 is fixed on the fixed ring 7, and a drive gear 10 is fixed on the output shaft of the first drive motor 9. An internal gear ring 8 is fixed on the inner side of the annular rotating groove 2, and the internal gear ring 8 meshes with the drive gear 10. A second drive motor 12 is installed on the base 1. A rotating disk 11 is rotatably arranged in the middle position of the base 1. A vertical hydraulic cylinder 4 is fixed on the rotating disk 11, and the output shaft of the second drive motor 12 is connected to the rotating disk 11 through a belt drive pair 13.

[0064] It should be noted that the first drive motor 9 can drive the annular rotating groove 2 to rotate through the drive gear 10 and the internal gear ring 8, and the second drive motor 12 can drive the vertical hydraulic cylinder 4 to rotate through the belt drive pair 13 and the rotating disk 11, which in turn drives the rotating ring 5 to rotate. Moreover, the rotation direction of the rotating ring 5 is opposite to the rotation direction of the annular rotating groove 2, and both rotate intermittently.

[0065] like Figure 1 and Figure 3 As shown, a sliding sleeve 14 is fixed in the middle of the material cylinder 6, and a sliding rod 15 is slidably arranged in the middle of the sliding sleeve 14. A quick-connect assembly is provided between the upper end of the sliding rod 15 and the rotating ring 5. A feeding conveyor belt 16 and a discharging conveyor belt 17 are provided on the side of the base 1, and an acid washing tank 3 is spaced between the feeding conveyor belt 16 and the discharging conveyor belt 17.

[0066] It should be noted that during use, the material cylinder 6 containing the bolt body to be processed is moved to the lower end of the rotating ring 5 by the feeding conveyor belt 16. During pickling, the rotating ring 5 descends, and under the action of the quick-connect assembly, the end of the slide rod 15 is connected to the lower part of the rotating ring 5. As the rotating ring 5 rises, the slide rod 15 is pulled out. After being pulled out to its maximum extent, it can drive the sliding sleeve 14 and the material cylinder 6 to rise and detach from the feeding conveyor belt 16. Similarly, when the rotating ring 5 descends, the material cylinder 6 located above the discharge conveyor belt 17 will be placed on the discharge conveyor belt 17. Then the slide rod 15 retracts into the sliding sleeve 14, and the quick-connect assembly is disconnected, thereby realizing automatic loading and unloading, improving the degree of automation, and improving production efficiency.

[0067] like Figure 3 As shown, the quick-connect assembly includes a sleeve 18 fixed to the lower end of the rotating ring 5. The sleeve 18 has an installation port 22 on its side wall, and a locking tongue 23 is slidably disposed in the installation port 22. An installation shell 24 is fixed to the outside of the installation port 22, and a compression spring 25 for pressing the locking tongue 23 is disposed in the installation shell 24. The end of the locking tongue 23 is provided with a downward-facing first chamfer. A connector 19 is provided at the upper end of the slide rod 15. A clamp 20 is fixed at the upper end of the connector 19. A lifting ring 21 is slidably sleeved on the connector 19. The lifting ring 21 is located below the clamp 20, and the upper edge of the clamp 20 is provided with a second chamfer. The lower outer edge of the lifting ring 21 is provided with a third chamfer, and the height of the feeding conveyor belt 16 is lower than that of the discharging conveyor belt 17.

[0068] It should be noted that at the feeding point, when the sleeve 18 descends, the clamp 20 located directly below it will push the locking tongue 23 to both sides and pass over the locking tongue 23. Then, the locking tongue 23 will be reset under the action of the compression spring 25 and will be locked under the clamp 20, which will drive the connector 19 to move upward, thereby achieving the effect of lifting the material cylinder 6. At the discharging point, when the sleeve 18 descends, the material cylinder 6 is placed on the discharge conveyor belt 17, and then the slide rod 15 retracts into the slide sleeve 14. Since the discharge conveyor belt 17 is higher, the connector 19 can continue to go deeper into the sleeve 18 when the sleeve 18 descends, and the lifting ring 21 will move above the locking tongue 23. Then the sleeve 18 rises, and the locking tongue 23 drives the lifting ring 21 to rise. When the lifting ring 21 abuts against the clamp 20, the locking tongue 23 will separate to both sides under the action of the third chamfer. At this time, the locking tongue 23 can pass over the lifting ring 21 and the clamp 20 at the same time, thereby achieving the effect of lowering the material cylinder 6.

[0069] like Figure 5 As shown, the lower end of the material cylinder 6 is fixed with several support feet 26, and the bottom of the support feet 26 is rotatably equipped with ball bearings 27.

[0070] It should be noted that when the rotating ring 5 descends, the sleeve 18 will be fitted onto the connector 19. At this time, the discharge conveyor belt 17 cannot drive the material cylinder 6 to move. At this time, the ball bearings 27 at the bottom of the material cylinder 6 can reduce the friction between it and the discharge conveyor belt 17, preventing the material cylinder 6 from jamming or tipping over.

[0071] like Figure 6 As shown, a support rod 28 is fixed on the base 1. The support rod 28 is located between the feed conveyor belt 16 and the discharge conveyor belt 17. A feeding pipe 29 for adding acid is fixed to the upper end of the support rod 28. A swing plate 30 is rotatably installed on the feeding pipe 29. A concentration sensor 31 and a counterweight 32 are installed at the lower end of the swing plate 30.

[0072] It should be noted that during acid replenishment, the system can automatically stop when the acid concentration reaches a certain value based on the detection data of the concentration sensor 31, making operation more convenient. Moreover, when the annular rotating tank 2 rotates, the swing plate 30 can be pushed to the side by the side wall of the pickling tank 3 and rotate to the side. After passing the side wall of the pickling tank 3, it will return to the vertical state under the action of gravity and proceed to the next pickling tank 3 for detection. There is no need to install multiple concentration sensors 31, making it simple to use and low in cost.

[0073] Based on this, a high-strength wear-resistant bolt is also proposed, comprising a bolt body 33, wherein the bolt body 33 is provided with a threaded portion 34, and the threaded portion 34 is coated with a ceramic-reinforced composite coating, wherein the ceramic-reinforced composite coating comprises the following components by weight percentage:

[0074] Alumina 35%-45%, particle size 1-3μm;

[0075] Silicon carbide 20%-30%, particle size 0.5-2μm;

[0076] Polytetrafluoroethylene (PTFE) 10%-15%, molecular weight 500,000-1,000,000;

[0077] Epoxy resin adhesive 15%-25%, curing shrinkage rate ≤2%;

[0078] Dispersant 0.5%-1.0%;

[0079] Defoamer 0.1%-0.3%;

[0080] The ceramic-reinforced composite coating has a thickness of 50-80 μm and is formed by a staged temperature-curing process, which includes: pre-drying at 80°C for 1 hour, preliminary cross-linking at 150°C for 2 hours, and complete curing at 200°C for 1 hour.

[0081] Preferably, in the ceramic-reinforced composite coating, the weight ratio of alumina to silicon carbide is 1.5:1 to 2:1, and the viscosity of the epoxy resin binder at 200°C is 500-1000 mPa·s.

[0082] A ceramic-reinforced composite coating achieves a synergistic effect between the hard phase, lubricating phase, and binder phase. Alumina and silicon carbide form a hard framework, with alumina providing basic hardness and silicon carbide improving fatigue resistance through grain refinement. When combined in a weight ratio of 1.5:1 to 2:1, they simultaneously optimize wear resistance and impact resistance. Polytetrafluoroethylene (PTFE) acts as the lubricating phase, forming a low-shear-strength transfer film during friction, transforming dry friction into polymer internal friction and significantly reducing the risk of seizure. Epoxy resin binder chemically bonds and encapsulates the ceramic particles; its viscosity of 500-1000 mPa·s at 200°C balances spray flowability and coating density, ultimately forming a composite structure with a porosity ≤1%.

[0083] The coating employs a three-stage temperature-curing process: pre-drying at 80℃ removes adsorbed moisture to prevent subsequent porosity; initial cross-linking at 150℃ fixes the position of ceramic particles, preventing agglomeration during rapid curing at 200℃; and complete curing at 200℃ forms a network structure with a cross-linking density ≥0.8 mol / cm³, increasing the bonding strength between the coating and the bolt body to over 25 MPa. This process, by controlling the cross-linking rate of the epoxy resin, reduces the internal stress of the coating to 30% of that achieved with traditional processes, significantly improving its anti-peeling performance.

[0084] Laboratory tests show that under dry friction conditions, the wear rate of this coating is only 0.02 mm / year; under silt erosion conditions, the wear rate is reduced to 0.5 mg / 1000 revolutions. The core mechanism lies in the fact that the hard ceramic phase bears the main load, the PTFE transfer film reduces direct contact, and the epoxy resin binder inhibits crack propagation. In practical applications of wind turbine gearbox bolts, after 5 years of operation, the fastening force retention rate is still ≥95%, and the maintenance interval has been extended from 3 months to 12 months.

[0085] Through the synergistic design of SiC grain refinement and epoxy resin stress buffering, the coating achieves an impact strength of 50 J / cm², maintaining stable performance in temperature-varying environments ranging from -40℃ to 150℃. Salt spray testing shows no red rust after 2000 hours, superior to the 500 hours of traditional galvanized bolts. Furthermore, the hydrophobicity of PTFE and the chemical resistance of epoxy resin enable the coating to continue its long-term service life in extreme environments.

[0086] The coating density is only 2.8 g / cm³, meeting the requirements for lightweighting. Although the cost of ceramic raw materials accounts for 60% of the total cost of the coating, its characteristic of extending the lifespan by 3 times reduces the total life cycle cost by 50%.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A manufacturing process for high-strength wear-resistant bolts, characterized in that: include: S1: Material selection: Select the bolt body to be processed, and clean and dry it; S2: Annealing treatment: Heat the bolt body to be processed to 800℃~920℃ and hold for 30 minutes, then cool down to 680℃~700℃ and hold for 80 minutes, then cool down to 480℃~500℃ and air cool. S3: Clean and dry the bolt body prepared in step S2 again, then heat it to 560℃~580℃, keep it at that temperature for 80min~90min and then cool it. S4: Chemical pickling: The bolt body to be processed is chemically pickled multiple times using pickling equipment; The pickling equipment includes a base (1), an annular rotating groove (2) is rotatably arranged above the base (1), and several pickling tanks (3) of the same specifications are arranged inside the annular rotating groove (2). A vertical hydraulic cylinder (4) is rotatably arranged in the middle position of the base (1). A rotating ring (5) is fixed at the top of the vertical hydraulic cylinder (4). Several material cylinders (6) for placing the bolt bodies to be processed are arranged at equal intervals below the rotating ring (5). The material cylinders (6) are aligned with the pickling tanks (3) at the corresponding positions. Several small holes are opened on the side wall of the material cylinders (6) to facilitate the entry and exit of pickling liquid. A driving mechanism is provided on the base (1) to drive the annular rotating groove (2) and the vertical hydraulic cylinder (4) to rotate. S5: Forming: The bolt body to be processed is placed in a multi-station automatic cold heading machine, and after being processed by stamping, forging, extrusion and diameter reduction, a blank is obtained. The blank is then rolled by a rolling die to process a semi-finished bolt body with threaded part (34) on its surface. S6: Quenching: Quench the semi-finished bolt body at a quenching temperature of 850℃~900℃ for 28min~37min, and then quickly immerse it in a quenching oil bath for cooling. S7: Tempering: Temper the quenched semi-finished bolt body at a temperature of 370℃~390℃ for 80min~120min, and then allow it to cool naturally. S8: Grinding: Place the tempered semi-finished bolt body into a vibrating sand shot blasting machine to remove the burrs on the surface of the semi-finished bolt body using sand particles. S9: Electroplating: The semi-finished bolt body after grinding is placed in an electroplating bath for electroplating treatment to obtain the finished bolt body (33). S10: A ceramic-reinforced composite coating is plated on the outside of the threaded portion (34) to obtain a high-strength wear-resistant bolt; The drive mechanism includes a fixed ring (7) fixed on the base (1), and an annular rotating groove (2) sleeved on the outside of the fixed ring (7). A first drive motor (9) is fixed on the fixed ring (7), and a drive gear (10) is fixed on the output shaft of the first drive motor (9). An internal gear ring (8) is fixed on the inner side of the annular rotating groove (2), and the internal gear ring (8) meshes with the drive gear (10). A second drive motor (12) is installed on the base (1). A rotating disk (11) is rotatably set in the middle position of the base (1). A vertical hydraulic cylinder (4) is fixed on the rotating disk (11), and the output shaft of the second drive motor (12) is connected to the rotating disk (11) through a belt drive pair (13). A sliding sleeve (14) is fixed in the middle of the material cylinder (6), and a sliding rod (15) is slidably arranged in the middle of the sliding sleeve (14). A quick-connect assembly is provided between the upper end of the sliding rod (15) and the rotating ring (5). A feeding conveyor belt (16) and a discharging conveyor belt (17) are provided on the side of the base (1), and an acid washing tank (3) is spaced between the feeding conveyor belt (16) and the discharging conveyor belt (17). The quick-connect assembly includes a sleeve (18) fixed to the lower end of the rotating ring (5). The sleeve (18) has an installation port (22) on its side wall, and a locking tongue (23) is slidably provided in the installation port (22). An installation shell (24) is fixed to the outside of the installation port (22), and a compression spring (25) for pressing the locking tongue (23) is provided in the installation shell (24). The end of the locking tongue (23) is provided with a downward-facing first chamfer. A connector (19) is provided at the upper end of the slide rod (15). A clamp (20) is fixed at the upper end of the connector (19). A lifting ring (21) is slidably sleeved on the connector (19). The lifting ring (21) is located below the clamp (20), and the upper edge of the clamp (20) is provided with a second chamfer. The lower outer edge of the lifting ring (21) is provided with a third chamfer, and the height of the feeding conveyor belt (16) is lower than that of the discharging conveyor belt (17). The lower end of the material cylinder (6) is fixed with several support feet (26), and the bottom of the support feet (26) is rotatably provided with ball bearings (27). A support rod (28) is fixed on the base (1). The support rod (28) is located between the feed conveyor belt (16) and the discharge conveyor belt (17). A feeding pipe (29) for adding acid solution is fixed at the upper end of the support rod (28). A swing plate (30) is rotatably installed on the feeding pipe (29). A concentration sensor (31) and a counterweight (32) are installed at the lower end of the swing plate (30). The ceramic-reinforced composite coating comprises the following components by weight percentage: Alumina 35%-45%, particle size 1-3μm; Silicon carbide 20%-30%, particle size 0.5-2μm; Polytetrafluoroethylene 10%-15%; Epoxy resin adhesive 15%-25%, curing shrinkage rate ≤2%; Dispersant 0.5%-1.0%; Defoamer 0.1%-0.3%; The ceramic-reinforced composite coating has a thickness of 50-80 μm and is formed by a staged temperature-curing process, which includes: pre-drying at 80°C for 1 hour, preliminary cross-linking at 150°C for 2 hours, and complete curing at 200°C for 1 hour.

2. The manufacturing process for a high-strength wear-resistant bolt according to claim 1, characterized in that: In step S8, the mesh size of the sand particles is 400-800 mesh.

3. A high-strength wear-resistant bolt, characterized in that: The bolt body (33) is prepared by the high-strength wear-resistant bolt manufacturing process described in claim 1. The bolt body (33) is provided with a threaded portion (34). The threaded portion (34) is coated with a ceramic-reinforced composite coating. The ceramic-reinforced composite coating comprises the following components by weight percentage: Alumina 35%-45%, particle size 1-3μm; Silicon carbide 20%-30%, particle size 0.5-2μm; Polytetrafluoroethylene 10%-15%; Epoxy resin adhesive 15%-25%, curing shrinkage rate ≤2%; Dispersant 0.5%-1.0%; Defoamer 0.1%-0.3%; The ceramic-reinforced composite coating has a thickness of 50-80 μm and is formed by a staged temperature-curing process, which includes: pre-drying at 80°C for 1 hour, preliminary cross-linking at 150°C for 2 hours, and complete curing at 200°C for 1 hour.

4. A high-strength wear-resistant bolt according to claim 3, characterized in that: In the ceramic-reinforced composite coating, the weight ratio of alumina to silicon carbide is 1.5:1 to 2:1, and the viscosity of the epoxy resin binder at 200°C is 500-1000 mPa·s.

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