Nickel-based alloy composite board surface polishing process based on vacuum rolling

Abstract

The invention discloses a nickel-based alloy composite board surface polishing process based on vacuum rolling, and relates to the technical field of metal material processing, and the process comprises the following specific steps: firstly, carrying out surface pretreatment on a nickel-based alloy composite board subjected to vacuum rolling and TMCP state or QT state heat treatment, including alkaline cleaning, acid spraying and the like; carrying out double-frequency plasma gradient treatment; then, magnetorheological fluid containing an elastic core-shell structure abrasive material is used for collaborative polishing; then carrying out bio-based fine polishing; and finally, carrying out ultrasonic cleaning, chromate passivation and drying and cooling to room temperature to finish post-treatment. Efficient polishing of the nickel-based alloy composite plate is achieved through a multi-section type synergistic process; the interface bonding is enhanced and the surface layer structure is optimized through dual-frequency plasma treatment; the flatness is improved through the cooperation of magneto-rheological and polishing by means of special grinding materials; the bio-based polishing solution realizes green polishing; and the performance and reliability of the composite board are comprehensively improved through technical innovation such as dynamic magnetic field regulation.

Description

Technical Field

[0001] This invention relates to the field of metal material processing technology, specifically to a surface polishing process for nickel-based alloy composite plates based on vacuum rolling. Background Technology

[0002] Nickel-based alloy composite plates occupy an important position in high-end industrial fields such as petrochemicals, energy and power, and aerospace due to their excellent high-temperature strength, corrosion resistance, and cost-effectiveness. These composite plates are usually prepared by vacuum rolling combined with specific heat treatment methods to achieve effective bonding between the base layer and the cladding, meeting the comprehensive performance requirements of materials under different working conditions. However, during the preparation process, rolling oil stains, oxide scale, and micro-defects are easily left on the surface of the composite plate, and microscopic voids or impurities may exist at the interface between the base layer and the cladding. These problems directly affect the surface finish, interface bonding stability, and subsequent corrosion resistance of the composite plate. Therefore, surface polishing has become a key link in improving the performance and reliability of nickel-based alloy composite plates. Its processing effect not only determines the appearance quality of the material, but is also closely related to the service life of the material in harsh environments. With the continuous improvement of material performance requirements in the industrial field, traditional polishing processes are no longer able to meet the processing requirements of high precision, high stability, and green environmental protection. Developing efficient polishing technology that is compatible with vacuum rolling and different heat treatment states of nickel-based alloy composite plates has become an important direction for industry development.

[0003] Traditional polishing processes for nickel-based alloy composite plates have significant limitations in several stages, making it difficult to balance processing quality, efficiency, and environmental friendliness. In the pretreatment stage, conventional cleaning methods often fail to completely remove residual oil and oxide impurities, easily leading to defects in subsequent processing and affecting the polishing effect. Plasma treatment technology mostly uses single-frequency bombardment, failing to target the bonding interface and the coating surface of the composite plate separately, resulting in limited improvement in interface bonding strength and poor optimization of the surface microstructure. In magnetorheological polishing processes, traditional abrasives are mostly single rigid or elastic materials, making it difficult to achieve both grinding efficiency and surface finish. The dynamic balance of surface protection can easily lead to processing defects such as scratches and dents on the surface of composite panels. Some polishing processes rely on chemical polishing agents, which not only easily pollute the environment but may also corrode the surface of the composite panels, reducing the corrosion resistance of the materials. In addition, traditional post-processing processes often have problems such as incomplete cleaning or insufficient passivation, resulting in residual impurities or insufficient density of the passivation film on the surface of the composite panels, which cannot effectively resist the erosion of external corrosive media. Moreover, most processes have poor adaptability to composite panels with different heat treatment states, which can easily lead to problems such as poor processing consistency and unstable product quality, making it difficult to meet the stringent requirements of high-end industrial fields for materials. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a surface polishing process for nickel-based alloy composite plates based on vacuum rolling. The process includes surface pretreatment using alkaline cleaning and mixed acid spraying; dual-frequency plasma gradient treatment using argon or nitrogen gas for dual-frequency bombardment under vacuum; magnetorheological synergistic polishing using a magnetorheological fluid containing elastic core-shell abrasives to apply a dynamic gradient magnetic field; bio-based fine polishing using a chitosan-tea polyphenol bio-based polishing fluid; and post-treatment including ultrasonic cleaning, chromate passivation, and drying and cooling.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a surface polishing process for nickel-based alloy composite plates based on vacuum rolling, the specific steps of which are as follows:

[0006] S100, Surface pretreatment: Select nickel-based alloy composite plates that have undergone vacuum rolling and TMCP or QT state heat treatment, and then clean them with alkaline solution at 40-60℃, spray them with mixed acid, rinse them with deionized water until the pH value is 6.5-7.5, and then dry them; where TMCP state indicates thermomechanical control process state, and QT state indicates quenching and tempering state;

[0007] S200, Dual-Frequency Plasma Gradient Treatment: The composite plate is placed in a vacuum plasma device and evacuated to 10... -3 -10 -2 Pa, and argon or nitrogen gas with a purity ≥99.99% is introduced, and the interface and the coating surface are bombarded at dual frequencies through the same electrode assembly; the interface refers to the bonding interface between the base layer and the coating of the nickel-based alloy composite plate, and the coating surface refers to the outer surface of the composite plate.

[0008] S300, Magnetorheological Co-polishing: A composite plate is polished by applying a dynamic gradient magnetic field to a magnetorheological fluid containing an elastic core-shell abrasive. The elastic core-shell abrasive is Fe3O4@TiO2@PDMS abrasive, where @ represents the core-shell structure, using Fe3O4 as the core, TiO2 as the middle layer, and PDMS as the outer layer. PDMS is polydimethylsiloxane.

[0009] S400, Bio-based Fine Polishing: Prepare chitosan-tea polyphenol bio-based polishing liquid, immerse the composite plate in it and then fine polish it with a soft polishing pad;

[0010] S500, post-treatment: ultrasonic cleaning, chromate passivation, drying and cooling to room temperature.

[0011] Furthermore, in the S100 surface pretreatment, the alkaline cleaning uses 20-25wt% sodium hydroxide or sodium carbonate cleaning agent. Sodium hydroxide is selected when the mineral oil residue is ≥5g / m², and sodium carbonate is selected when the mineral oil residue is <5g / m². The mixed acid is a mixed solution of 10-15% hydrochloric acid and 5-8% nitric acid.

[0012] Furthermore, in the S200 dual-frequency plasma gradient treatment, the argon or nitrogen gas flow rate is 10-20 L / min, and the chamber pressure fluctuation does not exceed 5 × 10⁻⁶. -4 Pa.

[0013] Furthermore, in the S200 dual-frequency plasma gradient treatment, the dual-frequency bombardment is as follows: first, the interface is bombarded with a low frequency, and then the surface is bombarded with a high frequency; the low-frequency bombardment parameters are 10-30kHz, and the bombardment time is 3-5min; the high-frequency bombardment parameters are 70-100kHz, and the bombardment time is 2-3min.

[0014] Furthermore, in the S300 magnetorheological co-polishing process, the Fe3O4 magnetic core particle size of the elastic core-shell Fe3O4@TiO2@PDMS abrasive is 0.8-2.5μm, the TiO2 intermediate layer thickness is 0.1-0.3μm, the PDMS elastic outer layer thickness is 0.3-0.5μm, the mass concentration of the abrasive in the magnetorheological fluid is 15-20%, and the saturation magnetization is 60-80 emu / g, where emu / g represents the electromagnetic unit per gram.

[0015] Furthermore, in the S300 magnetorheological co-polishing process, the dynamic gradient magnetic field is generated by an array of 20-30 electromagnetic coils, which linearly increases from 0.2T to 0.5T along the polishing path at a rate of 0.05-0.1T / min; the polishing head is made of polyurethane-coated tungsten carbide, and the polishing path is spiral.

[0016] Furthermore, in the S400 bio-based fine polishing solution, the bio-based polishing solution contains 2-5 wt% chitosan and 0.5-1 wt% tea polyphenols. The chitosan has a molecular weight of 50,000-100,000 Da and a purity of ≥95%. The tea polyphenols have a purity of ≥98% and a catechin content of ≥70%. The pH value of the polishing solution is 6.5-7.5. Wherein Da represents Dalton.

[0017] Furthermore, in the S400 bio-based fine polishing process, the preparation process of the bio-based polishing solution is as follows: dissolve chitosan in a 1-2wt% glacial acetic acid aqueous solution, stir at 30-40℃ for 30 min, add tea polyphenols and continue stirring for 15 min, adjust the pH value to 6.5-7.5 with 0.1mol / L sodium hydroxide solution, and then disperse by ultrasonication at 200-300W and 40kHz for 10 min.

[0018] Furthermore, in the S500 post-processing, the ultrasonic cleaning power is 300-500W, the temperature is 40-50℃, and the time is 10-15min; the chromate solution is a sodium chromate or potassium chromate solution with a mass fraction of 5-10%, and 0.5-1wt% sodium nitrate is added; the passivation temperature is 50-60℃ and the time is 20-30min; the drying temperature is 80-100℃ and the time is 30-40min. During drying, the composite plate is suspended with a plate spacing ≥50mm and a cooling rate ≤5℃ / min.

[0019] Compared with existing technologies, this vacuum-rolled nickel-based alloy composite plate surface polishing process has the following advantages:

[0020] I. This invention achieves efficient unification of surface modification and polishing of nickel-based alloy composite plates by integrating a multi-stage synergistic process of surface pretreatment, dual-frequency plasma gradient treatment, magnetorheological synergistic polishing, and bio-based fine polishing. The dual-frequency plasma treatment acts on the interface and the coating surface separately, which not only strengthens the bonding stability between the base layer and the coating, but also optimizes the surface microstructure, laying a good foundation for subsequent polishing. The magnetorheological synergistic polishing relies on a special core-shell structure abrasive to achieve a dynamic balance between rigid grinding and elastic buffering, effectively reducing surface defects and improving surface smoothness and gloss. The bio-based polishing fluid is prepared with natural ingredients, which has both polishing efficiency and mild protective properties, avoiding the environmental pollution and surface damage problems of traditional chemical polishing agents. It achieves green polishing while further refining the surface roughness, so that the surface of the composite plate meets the high-precision requirements, taking into account both processing effect and environmental benefits.

[0021] II. This invention comprehensively improves the overall performance and reliability of nickel-based alloy composite plates through technological innovations such as dynamic magnetic field control, differentiated dual-frequency bombardment design, and systematic optimization of post-processing. Precise adjustment of the dynamic gradient magnetic field during magnetorheological polishing ensures uniform distribution of polishing force along the path, guaranteeing consistency in large-area processing and avoiding localized processing defects. The stepwise action strategy of dual-frequency plasma enhances interfacial bonding strength and improves surface physicochemical properties, enhancing the composite plate's anti-peeling ability. The synergistic combination of ultrasonic cleaning and passivation in the post-processing stage effectively removes residual impurities and oxide layers from the surface, forming a dense passivation protective film that significantly enhances the composite plate's corrosion resistance and oxidation resistance. The entire process is adaptable to composite plates under different heat treatment states, with tight process connections and controllable operation, improving production efficiency while ensuring product quality stability and expanding the application range of nickel-based alloy composite plates under harsh working conditions.

[0022] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 This is a flowchart of the surface polishing process for nickel-based alloy composite plates based on vacuum rolling. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0026] Example 1:

[0027] Example of polishing TMCP-state nickel-based alloy composite plate for chemical reaction vessels.

[0028] Scenario Description: This embodiment is applicable to the inner wall of a highly corrosive reactor in the chemical industry that is in long-term contact with acidic and alkaline media. The nickel-based alloy composite plate being treated is made by vacuum rolling and TMCP heat treatment. The surface retains rolled oxide scale and has a mineral oil residue of ≥5g / m². Polishing is required to reduce surface roughness and enhance corrosion resistance, ensuring the reactor's long-term stable operation in highly corrosive environments. The specific steps are as follows: Figure 1 As shown.

[0029] S100, Surface pretreatment:

[0030] A nickel-based alloy composite plate, vacuum rolled and heat-treated in the TMCP state, was selected and placed in a 22wt% sodium hydroxide cleaning agent at 45℃ for alkaline cleaning. The 45℃ temperature enhances the activity of the cleaning agent, and the 22wt% sodium hydroxide can fully dissolve mineral oil and attached oil stains ≥5g / m² on the surface, preventing impurities from affecting the interface bonding and polishing effect in subsequent processes. Subsequently, the surface of the composite plate was sprayed with a mixed acid solution of 12% hydrochloric acid and 6% nitric acid. The hydrochloric acid can dissolve the metal oxides in the rolled oxide scale, while the nitric acid can help remove surface rust and inhibit excessive dissolution of the metal matrix, achieving thorough removal of surface impurities through a synergistic effect. Next, the composite plate was continuously rinsed with deionized water until the pH value of the water reached 7.0 after rinsing, completely removing residual acid and alkali solutions and preventing new corrosion marks from forming on the surface of the composite plate due to acid and alkali residue. Finally, the composite plate was dried to ensure that there was no moisture residue on the surface, avoiding water stains from interfering with the vacuum environment of subsequent plasma treatment.

[0031] S200, dual-frequency plasma gradient processing:

[0032] The pretreated composite plate was placed inside the vacuum plasma device, and the vacuum pump was started to evacuate to 5×10⁻⁶. -3 The vacuum level of Pa is sufficient to eliminate air and impurities from the device, preventing oxidation or nitriding reactions between oxygen, nitrogen, and other gases on the composite plate surface during bombardment. Argon gas with a purity ≥99.99% is introduced into the device, with the flow rate controlled at 15 L / min, while ensuring that the pressure fluctuation in the chamber does not exceed 5 × 10⁻⁶ Pa. -4 A stable argon atmosphere maintains a uniform plasma morphology, providing a consistent reaction environment for subsequent dual-frequency bombardment. Using the same electrode assembly, the interface between the base layer and the cladding of the composite plate is first bombarded at a low frequency of 20 kHz for 3 minutes. This low-frequency energy penetrates to the interface region, activating atomic activity, reducing interfacial voids and defects, and improving the bonding strength between the base layer and the cladding. Subsequently, the cladding surface of the composite plate is bombarded at a high frequency of 85 kHz for 2.5 minutes. This concentrated high-frequency energy on the surface refines the surface grains, improves the uniformity of the surface microstructure, and reduces surface stress, laying a smooth and dense surface foundation for subsequent magnetorheological polishing.

[0033] S300, magnetorheological co-polishing:

[0034] Polishing was performed using a magnetorheological fluid containing an Fe3O4@TiO2@PDMS elastic core-shell abrasive. The Fe3O4 magnetic core had a particle size of 1.5 μm, the TiO2 intermediate layer had a thickness of 0.2 μm, and the PDMS elastic outer layer had a thickness of 0.4 μm. The 1.5 μm magnetic core ensured sufficient magnetic response of the abrasive, the 0.2 μm TiO2 intermediate layer improved the hardness and wear resistance of the abrasive, and the 0.4 μm PDMS elastic outer layer buffered the impact force during polishing, preventing scratches on the composite plate surface. The abrasive concentration in the magnetorheological fluid was 18%, and the saturation magnetization was 70 emu / g. This concentration and magnetization match allowed the abrasive to perform polishing with optimal magnetic response. A stable polishing brush is formed under the action of the field, ensuring uniform polishing force. After the polishing equipment is started, a dynamic gradient magnetic field is generated through an array of 25 electromagnetic coils. The magnetic field linearly increases from 0.2T to 0.5T along the spiral polishing path, with a pressure increase rate of 0.08T / min. The gradient magnetic field allows the polishing force to be gradually adjusted along the path, avoiding local over-polishing or under-polishing. The spiral path can cover the entire surface of the composite board, ensuring no polishing dead corners. A polishing head made of polyurethane-coated tungsten carbide is used. The outer layer of polyurethane has a certain degree of elasticity and can conform to the surface undulations. The tungsten carbide core ensures the wear resistance and structural stability of the polishing head. Together with the magnetorheological fluid, it achieves efficient flattening treatment of the composite board surface.

[0035] S400, Bio-based Precision Polishing:

[0036] To prepare a chitosan-tea polyphenol bio-based polishing solution, chitosan with a molecular weight of 80,000 Da and a purity of 96% was first dissolved in a 1.5 wt% glacial acetic acid aqueous solution. The solution was stirred at 35°C for 30 minutes. The 35°C temperature and the 1.5 wt% glacial acetic acid concentration promoted the complete dissolution of chitosan, forming a uniform colloidal solution that provided a stable matrix for the dispersion of tea polyphenols. Then, tea polyphenols with a purity of 98.5% and a catechin content of 72% were added, and the mixture was stirred for another 15 minutes. The catechins in the tea polyphenols possess certain activity and can form a temporary protective film on the surface of the composite board during polishing, reducing oxidation reactions and improving the lubricity of the polishing solution. The pH of the polishing solution was adjusted to 7.0 using a 0.1 mol / L sodium hydroxide solution to avoid corrosion of the composite board surface due to excessive acidity or alkalinity. Finally, the composite board was ultrasonically dispersed at 250W and 40kHz for 10 minutes. The ultrasonic vibration could break up the agglomerated particles in the polishing solution, ensuring uniform dispersion of chitosan and tea polyphenols and avoiding uneven polishing effect caused by local concentration differences. The composite board after magnetorheological synergistic polishing was immersed in the bio-based polishing solution and finely polished using a soft polishing pad. The soft polishing pad could avoid secondary damage to the surface after magnetorheological polishing and, together with the bio-based polishing solution, further reduced surface roughness and improved surface smoothness and fineness.

[0037] S500, Post-processor:

[0038] The finely polished composite plate was placed in an ultrasonic cleaning device. The ultrasonic power was set to 400W, the cleaning temperature to 45℃, and the cleaning time to 12 minutes. The 400W ultrasonic power generated sufficient vibration, the 45℃ temperature enhanced the activity of the cleaning fluid, and the 12-minute duration ensured the thorough removal of residual polishing fluid components and abrasive particles from the surface, preventing residual substances from affecting the subsequent passivation film formation. Subsequently, the composite plate was immersed in a 5wt% sodium chromate solution with 0.8wt% sodium nitrate added. Passivation was performed at 55℃ for 25 minutes. The 5wt% sodium chromate formed a dense chromate oxide film on the composite plate surface, while the 0.8wt% sodium nitrate accelerated oxide film formation and improved film uniformity. The 55℃ temperature and 25min... The drying time ensures the oxide film thickness meets the standard, enhancing the corrosion resistance of the composite plate to adapt to the acid and alkaline environment of the reactor. After passivation, the composite plate is suspended in the drying equipment with a plate spacing of 60mm. The 60mm plate spacing ensures sufficient hot airflow and avoids uneven drying due to contact between composite plates. The drying temperature is set to 90℃ and the drying time is 35min. The 90℃ temperature can quickly remove surface moisture and avoid damage to the passivation film caused by high temperature. The 35min time ensures thorough drying. After drying, it is cooled to room temperature at a cooling rate of 3℃ / min. The slow cooling rate can prevent the composite plate from generating internal stress due to excessive temperature difference, avoiding plate deformation or performance fluctuation, and ultimately ensuring that the composite plate meets the usage requirements of the chemical reactor.

[0039] In summary, this embodiment describes a five-step process for achieving efficient polishing of TMCP-state nickel-based alloy composite plates used in chemical reactors. Step S100 involves degreasing with 45℃ 22wt% sodium hydroxide and removing oxide scale with 12% hydrochloric acid + 6% nitric acid to ensure surface cleanliness. Step S200 uses dual-frequency plasma to enhance interfacial adhesion and surface density. Step S300 employs magnetorheological polishing with a gradient magnetic field and elastic abrasives to achieve uniform smoothness. Step S400 uses bio-based fine polishing to further reduce roughness. Step S500 involves ultrasonic cleaning and chromate passivation to enhance corrosion resistance. The entire process is adaptable to acidic and alkaline chemical environments, ensuring the composite plate meets the long-term stable service requirements of the reactor.

[0040] Example 2:

[0041] Polishing example of QT-state nickel-based alloy composite plate for marine engineering.

[0042] Scenario Description: This embodiment is applicable to components such as ship decks and offshore platforms in marine engineering that are exposed to marine atmosphere and seawater splash environment for a long time. The nickel-based alloy composite plate is made by vacuum rolling and QT state heat treatment. The surface mineral oil residue is <5g / m² and there are slight rolling marks. Polishing process is required to improve the surface wear resistance and marine corrosion resistance, while reducing surface roughness to reduce marine organism adhesion and ensure that the components can be used for a long time in high salt and high humidity environment.

[0043] S100, Surface pretreatment:

[0044] Nickel-based alloy composite plates that have undergone vacuum rolling and QT (Quick Temper) heat treatment were selected and subjected to alkaline cleaning in a 24wt% sodium carbonate cleaning agent at 55℃. The 55℃ temperature enhances the cleaning power of sodium carbonate. 24wt% sodium carbonate, as a mild cleaning agent, effectively removes small amounts of mineral oil (<5g / m²) and adhering marine dust and impurities from the surface, while avoiding excessive corrosion of the surface layer formed by quenching and tempering of the QT-treated plates by strong alkali. Subsequently, the surface of the composite plates was sprayed with a mixture of 14% hydrochloric acid and 7% nitric acid. The soluble slight oxide film formed on the surface due to storage or transportation can be removed with 7% nitric acid, which can help remove the oxide film residue and slightly passivate the surface, exposing a clean substrate surface for subsequent plasma treatment. The composite board is repeatedly rinsed with deionized water until the pH value of the water reaches 7.2, which thoroughly removes the residual acid and alkali solutions on the surface and prevents the residual liquid from reacting with the board in subsequent processes. The composite board is then dried to keep the surface dry, so as to avoid moisture being introduced into the vacuum plasma device and affecting the treatment effect, while also preventing the humid environment from causing new rust on the surface.

[0045] S200, dual-frequency plasma gradient processing:

[0046] The pretreated composite plate was placed in a vacuum plasma device, and the vacuum pump was started to evacuate to 8 × 10⁻⁸ ℃. -3 Pa, 8×10 -3 A vacuum level of Pa effectively eliminates air from the device, preventing oxygen, carbon dioxide, and other gases in the air from reacting with the composite plate surface during plasma bombardment, thus ensuring a pure processing environment. Nitrogen gas with a purity ≥99.99% is introduced into the device, with the flow rate controlled at 18 L / min, while ensuring that the pressure fluctuation in the chamber does not exceed 5 × 10⁻⁶. -4 A stable nitrogen atmosphere not only maintains plasma morphology stability but also forms a slight nitriding on the surface of the composite plate during bombardment, improving surface hardness and wear resistance to meet the friction requirements of marine platforms. Using the same electrode assembly, the interface between the base layer and the cladding of the composite plate is first bombarded with a low-frequency parameter of 25kHz for 4 minutes. This low-frequency energy penetrates deep into the interface region, activating atomic movement, filling tiny gaps, and enhancing the interfacial bonding force of the QT-state composite plate to cope with vibrations and impacts generated by ship navigation or platform operations in the marine environment. Then, the cladding surface is bombarded with a high-frequency parameter of 90kHz for 2 minutes. This concentrated high-frequency energy acts on the surface, refining surface grains, reducing surface defects, and improving surface density, laying the foundation for subsequent polishing and corrosion resistance.

[0047] S300, magnetorheological co-polishing:

[0048] A magnetorheological fluid containing Fe3O4@TiO2@PDMS elastic core-shell abrasive was used. The Fe3O4 magnetic core had a particle size of 2.0 μm, the TiO2 intermediate layer had a thickness of 0.25 μm, and the PDMS elastic outer layer had a thickness of 0.35 μm. The 2.0 μm magnetic core possesses stronger magnetism, suitable for the relatively dense surface characteristics of QT state substrates. The 0.25 μm TiO2 intermediate layer enhances the abrasive's cutting ability to remove minor rolling marks, and the 0.35 μm PDMS elastic outer layer prevents surface scratches during polishing. The abrasive's mass concentration in the magnetorheological fluid was 16%, and the saturation magnetization was 65 emu / g. This concentration and magnetization match allows the abrasive to form a core-shell structure under the influence of a magnetic field. A polishing brush with moderate hardness ensures the removal of rolling marks while avoiding over-polishing. A dynamic gradient magnetic field is generated by an array of 28 electromagnetic coils. The magnetic field linearly increases from 0.2T to 0.5T along a spiral polishing path at a rate of 0.06T / min. This slow rate of increase allows for gradual changes in polishing intensity, ensuring uniform polishing across all areas of the QT-state board surface and reducing localized stress concentration. The spiral path fully covers the board surface, eliminating polishing dead zones. A polishing head made of polyurethane-coated tungsten carbide is used. The polyurethane outer layer adheres to the board surface, while the tungsten carbide core ensures the polishing head's wear resistance. Together with magnetorheological fluid, it removes surface rolling marks, improves surface smoothness, and reduces bumps caused by marine organisms.

[0049] S400, Bio-based Precision Polishing:

[0050] A chitosan-tea polyphenol bio-based polishing solution was prepared by dissolving chitosan with a molecular weight of 90,000 Da and a purity of 97% in a 1.8 wt% glacial acetic acid aqueous solution and stirring at 38°C for 30 min. The 38°C temperature and the 1.8 wt% glacial acetic acid concentration promoted the complete dissolution of chitosan, forming a high-viscosity homogeneous solution, providing a stable dispersion carrier for tea polyphenols. After adding tea polyphenols with a purity of 99% and a catechin content of 75%, stirring was continued for 15 min. The catechins in the high-purity tea polyphenols enhanced the lubricity of the polishing solution and also had a slight interaction with the surface of the composite board during polishing, improving the surface's antioxidant capacity and adapting it to the high-oxygen marine environment. A 0.1 m... The pH of the polishing solution was adjusted to 7.3 using 1 ol / L sodium hydroxide solution to prevent acidic environment from corroding the surface. The solution was then ultrasonically dispersed at 280W and 40kHz for 10 minutes. The ultrasonic vibration broke up agglomerated particles in the polishing solution, ensuring uniform distribution of chitosan and tea polyphenols and preventing uneven polishing due to localized concentration differences. The composite plate, after magnetorheological co-polishing, was immersed in the bio-based polishing solution and finely polished using a soft polishing pad. The soft polishing pad prevented damage to the smoothed surface and, in conjunction with the bio-based polishing solution, further reduced surface roughness, improved surface smoothness, and reduced the possibility of marine organism attachment. Simultaneously, the residual tea polyphenols provided short-term anti-corrosion protection.

[0051] S500, Post-processor:

[0052] The finely polished composite board was placed in an ultrasonic cleaning device. The ultrasonic power was set to 450W, the cleaning temperature to 48℃, and the cleaning time to 14 minutes. The 450W ultrasonic power generated stronger vibrations, the 48℃ temperature enhanced the activity of the cleaning fluid, and the 14-minute duration ensured thorough removal of residual polishing fluid components and micro-abrasive particles from the surface, preventing residues from affecting the adhesion of the passivation film. The composite board was then immersed in an 8wt% potassium chromate solution with 0.7wt% sodium nitrate added. Passivation was carried out at 58℃ for 28 minutes. The 8wt% potassium chromate solution formed a thicker chromate oxide film on the board surface, while the 0.7wt% sodium nitrate improved the density and uniformity of the film. The 58℃ temperature and 28 minutes... The drying time of 38 minutes ensures the full formation of the oxide film, enhancing the substrate's resistance to marine corrosion. After passivation, the composite board is suspended in the drying equipment with a spacing of 55mm between boards. This spacing ensures proper airflow and prevents uneven drying due to contact between boards. The drying temperature is set to 95℃ and the drying time to 38 minutes. The 95℃ temperature quickly removes surface moisture, and the 38-minute duration ensures thorough drying, preventing the passivation film from failing due to a humid environment. After drying, the substrate is cooled to room temperature at a rate of 4℃ / min. This slow cooling rate prevents internal stress from developing in the QT state due to rapid cooling, avoiding deformation or a decline in mechanical properties, ultimately ensuring that the composite board meets the requirements for use in marine engineering components.

[0053] In summary, this embodiment presents a customized polishing process for QT-state nickel-based alloy composite plates used in marine engineering. S100 involves degreasing with 24wt% sodium carbonate at 55℃ and removing the oxide film with 14% hydrochloric acid + 7% nitric acid; S200 uses nitrogen atmosphere plasma to enhance interface and surface hardness; S300 employs magnetorheological polishing to eliminate rolling marks; S400 uses bio-based fine polishing to reduce roughness and biofouling; and S500 uses high-concentration chromate passivation to improve resistance to marine corrosion. This process balances wear resistance and anti-adhesion properties, is suitable for high-salt and high-humidity marine environments, and ensures that the composite plate meets the requirements for use on ship decks and offshore platforms.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A surface polishing process for nickel-based alloy composite plates based on vacuum rolling, characterized in that, The specific steps of this process are as follows: S100, Surface pretreatment: Select nickel-based alloy composite plates that have undergone vacuum rolling and TMCP or QT state heat treatment, and then clean them with alkaline solution at 40-60℃, spray them with mixed acid, rinse them with deionized water until the pH value is 6.5-7.5, and then dry them; where TMCP state indicates thermomechanical control process state, and QT state indicates quenching and tempering state; S200, Dual-Frequency Plasma Gradient Treatment: The composite plate is placed in a vacuum plasma device and evacuated to 10... -3 -10 -2 Pa, and argon or nitrogen gas with a purity ≥99.99% is introduced, and the interface and the coating surface are bombarded at dual frequencies through the same electrode assembly; the interface refers to the bonding interface between the base layer and the coating of the nickel-based alloy composite plate, and the coating surface refers to the outer surface of the composite plate. S300, Magnetorheological Co-polishing: A composite plate is polished by applying a dynamic gradient magnetic field to a magnetorheological fluid containing an elastic core-shell abrasive. The elastic core-shell abrasive is Fe3O4@TiO2@PDMS abrasive, where @ represents the core-shell structure, using Fe3O4 as the core, TiO2 as the middle layer, and PDMS as the outer layer. PDMS is polydimethylsiloxane. S400, Bio-based Fine Polishing: Prepare chitosan-tea polyphenol bio-based polishing liquid, immerse the composite plate in it and then fine polish it with a soft polishing pad; S500, post-treatment: ultrasonic cleaning, chromate passivation, drying and cooling to room temperature.

2. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the S100 surface pretreatment, alkaline cleaning uses 20-25wt% sodium hydroxide or sodium carbonate cleaning agent. Sodium hydroxide is selected when the mineral oil residue is ≥5g / m², and sodium carbonate is selected when the mineral oil residue is <5g / m². The mixed acid is a mixed solution of 10-15% hydrochloric acid and 5-8% nitric acid.

3. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the S200 dual-frequency plasma gradient treatment, the argon or nitrogen gas flow rate is 10-20 L / min, and the chamber pressure fluctuation does not exceed 5 × 10⁻⁶ L / min. -4 Pa.

4. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the S200 dual-frequency plasma gradient treatment, the dual-frequency bombardment is as follows: first, the interface is bombarded with a low frequency, and then the surface is bombarded with a high frequency; the low-frequency bombardment parameters are 10-30kHz, and the bombardment time is 3-5min; the high-frequency bombardment parameters are 70-100kHz, and the bombardment time is 2-3min.

5. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the S300 magnetorheological co-polishing process, the Fe3O4 magnetic core of the elastic core-shell Fe3O4@TiO2@PDMS abrasive has a particle size of 0.8-2.5 μm, the TiO2 intermediate layer thickness is 0.1-0.3 μm, the PDMS elastic outer layer thickness is 0.3-0.5 μm, the mass concentration of the abrasive in the magnetorheological fluid is 15-20%, and the saturation magnetization is 60-80 emu / g, where emu / g represents the electromagnetic unit per gram.

6. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the S300 magnetorheological co-polishing process, the dynamic gradient magnetic field is generated by an array of 20-30 electromagnetic coils, which linearly increases from 0.2T to 0.5T along the polishing path at a rate of 0.05-0.1T / min. The polishing head is made of polyurethane-coated tungsten carbide, and the polishing path is spiral.

7. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, The S400, a bio-based fine polishing solution, contains 2-5 wt% chitosan and 0.5-1 wt% tea polyphenols. The chitosan has a molecular weight of 50,000-100,000 Da and a purity of ≥95%. The tea polyphenols have a purity of ≥98% and a catechin content of ≥70%. The pH value of the polishing solution is 6.5-7.

5. Wherein Da represents Dalton.

8. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, The preparation process of the bio-based polishing solution in the S400 bio-based fine polishing is as follows: dissolve chitosan in 1-2wt% glacial acetic acid aqueous solution, stir at 30-40℃ for 30min, add tea polyphenols and continue stirring for 15min, adjust the pH value to 6.5-7.5 with 0.1mol / L sodium hydroxide solution, and disperse by ultrasonication at 200-300W and 40kHz for 10min.

9. The surface polishing process for nickel-based alloy composite plates based on vacuum rolling according to claim 1, characterized in that, In the post-processing of the S500, the ultrasonic cleaning power is 300-500W, the temperature is 40-50℃, and the time is 10-15min; the chromate solution is a sodium chromate or potassium chromate solution with a mass fraction of 5-10%, and 0.5-1wt% sodium nitrate is added; the passivation temperature is 50-60℃ and the time is 20-30min; the drying temperature is 80-100℃ and the time is 30-40min. During drying, the composite plate is suspended with a plate spacing of ≥50mm and a cooling rate of ≤5℃ / min.

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