Surface treatment process and application thereof in bicycle front fork assembly

Abstract

The invention discloses a surface treatment process for an aluminum alloy bicycle front fork assembly, and aims to solve the problems of the existing process and improve the performance of the front fork assembly. The process sequentially comprises the steps of pretreatment, micro-arc oxidation treatment, hole sealing treatment and super-hydrophobic coating preparation. In pretreatment, ultrasonic cleaning is combined with acid pickling to activate the aluminum alloy blank; micro-arc oxidation treatment: generating a wear-resistant ceramic film layer on the surface of the workpiece under a pulsed power supply by using a specific formula electrolyte; holes of the film layer are filled with organic silicon resin hole sealing liquid for hole sealing treatment; the super-hydrophobic coating is prepared by spraying a mixture of fluorocarbon resin and nano silicon dioxide, baking and curing. The process has the advantages that the adhesive force of the coating is enhanced, the hardness and the wear resistance are remarkably improved, the corrosion resistance and the self-cleaning property are excellent, the effect is remarkable through verification of an embodiment, the service life of the aluminum alloy bicycle front fork assembly can be effectively prolonged, and the application prospect is wide.

Description

Technical Field

[0001] The invention discloses a surface treatment process and its application in a bicycle front fork assembly. Background Art

[0002] In modern society, cycling is booming, and consumers' expectations for the performance and quality of bicycle components continue to rise. As a key stress-bearing component, the performance of the bicycle front fork assembly is directly related to the riding experience and safety. Aluminum alloy has become a common material for front fork manufacturing due to its light weight, high strength and good processability.

[0003] Although aluminum alloy front forks have many advantages, they face severe challenges. When riding outdoors, they are exposed to complex environments for a long time. Rainwater erosion forms a water film on the surface, dissolving harmful components and causing electrochemical corrosion; ultraviolet radiation causes aging and degradation of the surface organic coating; sand and stone wear destroys the integrity of the surface structure, affecting appearance and performance.

[0004] At present, the surface treatment process for aluminum alloy front forks has obvious defects. The traditional painting process is simple, but the coating has poor adhesion. Riding vibration and environmental factors can easily cause the coating to peel off, exposing the substrate, accelerating rust corrosion, and affecting the strength and life of the front fork. Although the electroplating process can form a protective coating, there are environmental issues, and it is difficult to repair the coating after it is damaged, making it difficult to maintain the durability and aesthetics of the front fork for a long time.

[0005] Therefore, in order to meet the needs of high performance, long life and environmental protection, a new and more effective surface treatment process for aluminum alloy front forks is urgently needed to improve their corrosion resistance, wear resistance, weather resistance and aesthetics to adapt to the development of the bicycle industry and consumer needs. Summary of the invention

[0006] The surface treatment process provided by the present invention and its application in a bicycle front fork assembly can effectively improve the service life of an aluminum alloy bicycle front fork.

[0007] A surface treatment process comprises the following steps:

[0008] 1. Preprocessing:

[0009] Ultrasonic cleaning equipment is used to perform deep cleaning operations on the aluminum alloy bicycle front fork component blanks. By setting the cleaning temperature between 50-60℃, the frequency to 30-40kHz, and maintaining the cleaning time for 15-20 minutes, surface oil, iron filings and other impurities can be effectively removed.

[0010] The cleaned workpiece is then placed in a 10-15% hydrochloric acid solution for pickling and activation, and the pickling time is strictly controlled within 3-5 minutes. This step can remove the surface oxide layer, activate the metal matrix, and create good surface conditions for subsequent processing. After the pickling is completed, the workpiece is thoroughly rinsed with clean water to neutral, and then dried with hot air to ensure that the surface is dry and free of residue.

[0011] 2. Micro-arc oxidation treatment:

[0012] The micro-arc oxidation electrolyte is prepared with sodium hydroxide as the main salt, and sodium silicate and sodium tungstate are added as additives in a specific ratio. Specifically, the sodium hydroxide concentration is maintained at 15-20g / L, the sodium silicate content is 3-5g / L, and the sodium tungstate content is 1-2g / L.

[0013] The pre-treated aluminum alloy front fork assembly is used as the anode, and the appropriate stainless steel plate is selected as the cathode, and they are placed together in the electrolyte. Under the precise control of the pulse power supply, a voltage of 400-500V is applied, while ensuring that the current density is 10-15A / dm 2 Range, micro-arc oxidation treatment is carried out for 20-30 minutes.

[0014] Through this process, a dense and uniform ceramic film layer is grown in situ on the surface of the aluminum alloy front fork assembly, significantly improving its hardness and wear resistance, and effectively resisting sand and gravel friction during riding.

[0015] 3. Sealing treatment: At the moment when the micro-arc oxidation treatment is completed, the workpiece is transferred to the pre-prepared sealing liquid containing silicone resin. The temperature of the sealing liquid is precisely controlled at 80-90°C, and the workpiece is immersed in it for 30-40 minutes. The silicone resin can fully fill the pores of the micro-arc oxidation ceramic film layer, further enhance the corrosion resistance of the film layer, and at the same time give the surface a certain self-cleaning property to reduce the adhesion of stains.

[0016] 4. Preparation of super hydrophobic coating:

[0017] The aluminum alloy front fork assembly that has been sealed and dried is placed in a dedicated spraying device. A mixture of fluorocarbon resin and nano-silicon dioxide with a mass ratio of 3:1 is used as the spray coating. This unique formula can give the coating excellent super-hydrophobic properties.

[0018] Set the spraying pressure between 0.3-0.4MPa, and perform meticulous spraying operations three times, strictly maintaining an interval of 15-20 minutes between each spraying to ensure that the paint is evenly and fully attached to the workpiece surface.

[0019] After spraying, the front fork assembly is placed in a high temperature environment of 120-150°C for baking and curing for 30-40 minutes. After this series of operations, a stable and super-hydrophobic coating is formed on the surface of the aluminum alloy front fork assembly, making it difficult for rainwater and stains to adhere, making it easy to clean and maintain, and further improving corrosion resistance.

[0020] Beneficial effects:

[0021] The pretreatment stage of this process can clean the workpiece surface very thoroughly through the synergistic effect of ultrasound and chemical pickling, laying a good foundation for subsequent processing and enhancing the bonding strength between each coating and the substrate.

[0022] The ceramic film layer generated by micro-arc oxidation has a hardness of up to 1500-2000HV, which significantly improves the wear and scratch resistance of the front fork components and can resist sand and gravel friction during riding.

[0023] The sealing treatment combined with the super-hydrophobic coating gives the front fork assembly excellent corrosion resistance. The salt spray test lasts for more than 500 hours with no obvious rust, and daily stains roll off by themselves with the rain, making it easy to clean and maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a bicycle front fork assembly that has undergone surface treatment. DETAILED DESCRIPTION

[0025] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0026] Example 1

[0027] A bicycle front fork component blank made of aluminum alloy was selected. The ultrasonic cleaning machine was started, the temperature was set to 55°C and the frequency was 35kHz, and the blank was placed in an alkaline degreasing agent solution for cleaning for 18 minutes. After cleaning, it was observed that the surface oil stains were basically removed, and it was transferred to a 12% hydrochloric acid solution for pickling for 4 minutes. After pickling, the workpiece was immediately rinsed with a large amount of clean water until the pH value of the rinse water reached neutral, and then dried with hot air.

[0028] Prepare the micro-arc oxidation electrolyte according to the following formula: sodium hydroxide concentration is 18g / L, sodium silicate concentration is 4g / L, and sodium tungstate concentration is 1.5g / L. Put the fork assembly as the anode and the stainless steel plate as the cathode into the electrolyte, connect the pulse power supply, set the voltage to 450V, and the current density to 12A / dm 2 , micro-arc oxidation treatment was carried out, and the treatment time was 25 minutes.

[0029] After the micro-arc oxidation treatment is completed, the workpiece is quickly placed in an 85°C silicone resin sealing liquid and immersed for 35 minutes. After the immersion is completed, the workpiece is removed and dried. The dried front fork assembly is placed in a spraying device, ready to be sprayed with a super-hydrophobic coating. The coating uses a mixture of fluorocarbon resin and nano-silicon dioxide in a mass ratio of 3:1. The spraying pressure is set to 0.35MPa, and the spraying is performed three times, with an interval of 18 minutes between each spraying. After spraying, the front fork assembly is placed in an oven at 130°C and baked for 35 minutes for curing. After testing, the surface hardness of the front fork assembly reached 1800HV. After 550 hours of salt spray test, no obvious signs of rust were found on the surface.

[0030] Example 2

[0031] Ultrasonic cleaning was performed on a steel bicycle front fork blank. The cleaning temperature was set to 50°C, the frequency was set to 40kHz, and the cleaning time was set to 20 minutes. After cleaning, it was pickled with a 10% hydrochloric acid solution for 5 minutes. After pickling, it was rinsed with clean water until it was neutral, and then dried with hot air.

[0032] Prepare a micro-arc oxidation electrolyte, in which the concentration of sodium hydroxide is 15g / L, the concentration of sodium silicate is 5g / L, and the concentration of sodium tungstate is 1g / L. During the micro-arc oxidation process, the voltage is set to 400V and the current density is 15A / dm 2 , the processing time is 30 minutes.

[0033] After the micro-arc oxidation treatment is completed, the workpiece is immersed in a sealing liquid at 80°C for 40 minutes. After the immersion, take it out and dry it, and then spray and bake the super-hydrophobic coating as required. According to the test, the wear resistance of the treated front fork assembly is 3 times higher than that before the treatment. After 3 months of outdoor rain test, there is no obvious stain residue on the surface, and the appearance remains good.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A surface treatment process, characterized in that: The method comprises the steps of pretreatment, micro-arc oxidation treatment, pore sealing treatment and super-hydrophobic coating preparation which are performed in sequence; The pretreatment includes: using ultrasonic cleaning equipment to clean the aluminum alloy bicycle front fork assembly blank; The micro-arc oxidation treatment includes: using sodium hydroxide as the main salt, adding sodium silicate and sodium tungstate as additives, placing the pre-treated aluminum alloy front fork assembly as the anode and the stainless steel plate as the cathode in the configured electrolyte, and performing micro-arc oxidation treatment under the precise control of the pulse power supply; The sealing treatment includes: immediately transferring the workpiece to a pre-prepared sealing liquid containing silicone resin and immersing it for a period of time after the micro-arc oxidation treatment is completed; The preparation of super-hydrophobic coating includes: placing the aluminum alloy front fork assembly that has completed the sealing treatment and dried in a special spraying equipment, setting the spraying pressure, and performing the spraying operation in multiple times, maintaining an interval time between each spraying, and after the spraying is completed, placing the front fork assembly in a high temperature environment for baking and curing.

2. A surface treatment process according to claim 1, characterized in that: In the pretreatment step, the cleaning temperature of the ultrasonic cleaning equipment is 50-60°C, the frequency is 30-40kHz, the cleaning time is 15-20 minutes, and after cleaning, the workpiece is placed in a 10-15% hydrochloric acid solution for pickling for 3-5 minutes, rinsed with clean water until neutral and blown dry with hot air.

3. A surface treatment process according to claim 1, characterized in that: In the micro-arc oxidation treatment step, the concentration of sodium hydroxide in the electrolyte is 15-20g / L, the content of sodium silicate is 3-5g / L, the content of sodium tungstate is 1-2g / L, the voltage during micro-arc oxidation treatment is 400-500V, and the current density is 10-15A / dm 2 , the processing time is 20-30 minutes.

4. A surface treatment process according to claim 1, characterized in that: In the sealing treatment step, the sealing liquid temperature is 80-90° C. and the immersion time is 30-40 minutes.

5. A surface treatment process according to claim 1, characterized in that: In the preparation step of the super-hydrophobic coating, the spray coating is a mixture of fluorocarbon resin and nano-silicon dioxide in a mass ratio of 3:1, the spraying pressure is 0.3-0.4MPa, and the spraying is performed three times, with an interval of 15-20 minutes between each spraying. The baking curing temperature is 120-150°C, and the baking time is 30-40 minutes.

6. Application of a surface treatment process according to claim 1 in a bicycle front fork assembly, characterized in that: The surface treatment process as claimed in any one of claims 1 to 5 is applied to a bicycle front fork assembly.

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