A polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and a preparation method thereof

Abstract

The present application relates to the technical field of multi-element sliding bearing composite material, and discloses a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and a preparation method thereof, wherein pure aluminum is used to composite aluminum-tin alloy and low carbon steel plate into aluminum-tin alloy-low carbon steel composite material plate by means of differential temperature rolling and heat treatment technology. Then, the pure aluminum layer on the surface of the aluminum-tin alloy is removed, and then the aluminum-tin alloy-low carbon steel composite material plate is sequentially subjected to surface cleaning, preheating, polymer spraying, solidification and segmented cooling treatment to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material plate. The present application effectively solves the technical problem that the aluminum-tin alloy cannot realize the synergistic optimization of comprehensive performance due to its low strength and degraded wear resistance, and the equipment is simple and convenient to modify, which can effectively reduce the initial pressing amount of rolling composite, reduce the load of rolling mill, prolong the service life of rolling mill, and realize continuous and large-scale batch production of the composite material plate.

Description

Technical Field

[0001] This invention relates to the field of multi-component sliding bearing composite materials, specifically to a polymer coating-aluminum-tin alloy-low carbon steel multi-component sliding bearing composite material and its preparation method. Background Technology

[0002] Compared to traditional sliding bearing materials such as copper-based alloys and Babbitt metals, aluminum-tin alloys are widely used in industrial fields such as internal combustion engines and wind turbine gearboxes due to their superior wear resistance, anti-galling, and embedding properties. However, aluminum-tin alloys have low strength and softness, requiring composite bonding with low-carbon steel to improve load-bearing capacity and fatigue strength. The composite bonding process has significant drawbacks: poor interfacial compatibility, with tin and iron easily forming hard and brittle tin-iron compounds that reduce bonding strength; direct bonding is prone to cracking due to differences in mechanical properties and interfacial issues; and tin's low melting point means that improper bonding temperatures can lead to precipitation and performance degradation of the aluminum-tin alloy, hindering its industrial application.

[0003] To address the aforementioned issues, existing technologies employ various methods to improve composite efficiency and quality. Rolling is the most widely used method (refer to the existing technology CN118357272A, which discloses an aluminum-tin alloy steel composite plate and its rolling method), optimizing the effect by controlling parameters such as rolling temperature, pressure, and speed. Some solutions involve pre-treatment of the low-carbon steel surface, such as grinding and pickling, to remove the oxide layer and increase roughness to enhance interfacial contact. Other technologies attempt to add trace amounts of intermediate alloying elements to improve interfacial compatibility and inhibit the formation of hard and brittle compounds.

[0004] However, the existing technology still has the following technical problems: (1) the rolling method has a narrow parameter control range and poor stability, and is prone to problems such as tin precipitation due to temperature fluctuations; (2) the interface pretreatment cannot suppress the interface reaction for a long time, and the bonding strength decreases after long-term use; (3) the addition of intermediate elements may introduce impurity phases, and the proportion is difficult to control, increasing the complexity and cost of the process. In addition, the existing technology has not solved the core problems of low strength and wear resistance degradation of aluminum-tin alloys. It only focuses on the interface bonding efficiency and cannot achieve comprehensive performance synergistic optimization, which is difficult to meet the needs of high-end equipment. There is an urgent need to develop a new composite technology solution. Summary of the Invention

[0005] The present invention aims to provide a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and its preparation method, so as to solve the technical problem that the low strength and wear resistance of aluminum-tin alloy itself still cannot be solved, thus failing to achieve comprehensive performance synergistic optimization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material, comprising the following steps:

[0007] Step 1: Rivet pure aluminum, aluminum-tin alloy and pure aluminum together to form a composite billet, perform multiple passes of room temperature rolling and first heat treatment, and after the composite billet cools to room temperature, obtain pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet.

[0008] Step 2: Fix the pure aluminum foil to the surface of the low carbon steel plate by riveting, and perform a room temperature rolling and a second heat treatment to obtain the pure aluminum / low carbon steel composite material plate.

[0009] Step 3: Rivet the heat-treated pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet and the pure aluminum / low carbon steel composite material sheet to form a composite billet, perform differential temperature rolling and a third heat treatment, and wait for the composite billet to cool to room temperature to obtain the aluminum-tin alloy-low carbon steel composite material sheet.

[0010] Step 4: Remove the pure aluminum layer from the aluminum-tin alloy surface of the aluminum-tin alloy-low carbon steel composite material sheet, and perform degreasing, degreasing, sandblasting, and cleaning treatments on the surface of the composite material sheet.

[0011] Step 5: Preheat, apply polymer coating, cure and segmented cooling to the surface of the aluminum-tin alloy-low carbon steel composite material sheet to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material sheet.

[0012] The principles and advantages of this scheme are:

[0013] 1. Step one of this solution adopts an "aluminum-tin alloy sandwich composite" to avoid interface risks and improve forming quality and mechanical stability. Specifically, the pure aluminum-aluminum-tin alloy-pure aluminum riveting structure utilizes the compatibility advantage of pure aluminum to avoid premature oxidation and precipitation of tin; while multi-pass room temperature rolling gradually improves the bonding strength, inhibits tin precipitation, and avoids the risk of temperature fluctuations; the first heat treatment effectively eliminates internal stress, improves the uniformity of the microstructure, and reduces the probability of subsequent cracking.

[0014] 2. Step two of this solution establishes a compatible interface through a pre-placed pure aluminum transition layer, fundamentally solving the compatibility problem of direct composite bonding between aluminum-tin alloy and low-carbon steel. Specifically, the pure aluminum foil isolates the iron-tin contact, inhibiting the formation of hard and brittle tin-iron compounds from the source and improving the interfacial bonding strength; while riveting combined with a single room temperature rolling process ensures a tight bond, avoids damage to the low-carbon steel, reduces process difficulty, and is suitable for industrialization; furthermore, it creates a gradient in mechanical properties, reduces material differences, and lowers the overall risk of composite cracking.

[0015] 3. Step three of this solution achieves precise fusion through heterogeneous rolling, and heat treatment optimizes interface quality, balancing composite efficiency and performance stability. Specifically, heterogeneous rolling precisely adapts to the characteristics of different billets, ensuring bonding while preventing tin precipitation; riveting pre-fixing effectively improves positioning accuracy, avoids interlayer misalignment, and ensures consistent composite quality; the third heat treatment effectively promotes atomic diffusion to strengthen bonding, eliminates internal stress, and improves overall mechanical properties. Through long-term experiments, the inventors discovered that in step three of this solution, compared to the "pure aluminum-aluminum-tin alloy-pure aluminum + low-carbon steel plate" structure formed during riveting, which is prone to low bonding strength due to the reaction between pure aluminum and carbon steel to form brittle intermetallic compounds, this solution forms a "pure aluminum-aluminum-tin alloy-pure aluminum + pure aluminum-low-carbon steel plate" structure during riveting. This structure effectively acts as a barrier to prevent direct contact between pure aluminum and carbon steel, inhibiting the formation of brittle intermetallic compounds, thereby improving shear bond strength and service reliability. Specifically, this design uses pure aluminum riveted to both sides of the aluminum-tin alloy to form a "double-layer aluminum structure." This serves two purposes: firstly, it acts as a buffer, with the pure aluminum layer acting as a "cushion," allowing the hard aluminum-tin alloy and the soft steel to deform more harmoniously. Secondly, it provides lubrication and protection, as the intermediate layer helps reduce foil breakage and increase yield during the rolling process. Finally, it refines the microstructure, contributing to a denser, finer columnar dendritic structure.

[0016] 4. Step four of this solution leverages the technical advantages of removing the pure aluminum layer and surface treatment to effectively expose the functional layer and purify and activate the surface, providing a high-quality substrate for polymer coating preparation and ensuring the core performance of the aluminum-tin alloy. Specifically, the pure aluminum layer is first removed to expose the aluminum-tin alloy functional layer, effectively preventing interference with coating bonding; the entire process of surface treatment thoroughly removes impurities, effectively improving surface activity and roughness, solving the problem of coating peeling; furthermore, sandblasting strengthens surface properties, effectively improving coating bonding strength and laying the foundation for functionalization.

[0017] 5. Step five of this solution utilizes precise temperature control and step-by-step curing to prepare a functional coating, achieving performance upgrades and avoiding material damage. Specifically, preheating improves coating compatibility and prevents coating cracking caused by temperature differences; the polymer coating imparts excellent wear and corrosion resistance, compensating for the insufficient strength of aluminum-tin alloys and achieving synergistic functions; segmented cooling effectively controls the coating forming quality, eliminates internal stress, protects the substrate, and ensures balanced performance.

[0018] Preferably, as an improvement, in step one, the initial reduction in the multi-pass room temperature rolling is 40%, and the reduction in each subsequent pass is 8-10%. In step two, the reduction in the single-pass room temperature rolling is 10%.

[0019] Beneficial effects: This solution adopts the above-mentioned scheme. The multi-pass room temperature rolling adopts a gradient design of "40% large reduction in the first pass + 8~10% small reduction in each subsequent pass". The large reduction in the first pass can quickly break the initial gap between pure aluminum and aluminum-tin alloy, realize rapid and tight bonding between layers, and efficiently lay a stable composite foundation. The subsequent small reduction of 8~10% can avoid damage to the material caused by large deformation, while gradually refining the interlayer structure and steadily improving the bonding strength. Combined with the room temperature environment, it can further avoid the risk of tin precipitation caused by excessive deformation, thus balancing composite efficiency and forming quality.

[0020] Preferably, as an improvement, in step one, the first heat treatment is performed at 250~350 °C for 60~90 min, followed by annealing.

[0021] Beneficial effects: The above-mentioned solution can ensure a tight contact between the pure aluminum foil and the low-carbon steel plate, meeting the interface bonding requirements for subsequent composites. It can also avoid the problem of damage to the surface of the low-carbon steel or breakage of the pure aluminum foil caused by excessive pressure. At the same time, the composite can be completed without multiple rolling passes, simplifying the process, reducing the difficulty of control, and improving the adaptability to industrial production.

[0022] Preferably, as an improvement, in step three, the process parameters for the differential temperature rolling are as follows: the rolling temperature of the pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet is room temperature, the rolling temperature of the pure aluminum / low carbon steel composite material sheet is 450~550 ℃, and the rolling reduction is 40~50%; the third heat treatment is heat treatment at 300~350 ℃ for 150~210 min, followed by annealing.

[0023] Beneficial effects: The above-mentioned scheme, with the third heat treatment and annealing, promotes the full diffusion of interlayer atoms through mild temperature and sufficient time, further strengthening the interfacial bonding strength. At the same time, it eliminates the internal stress generated by heterothermal rolling to the greatest extent. Annealing can further refine the microstructure and improve the overall mechanical properties and dimensional stability of the composite material.

[0024] Preferably, as an improvement, in step four, the degreasing treatment uses a solvent to perform ultrasonic oscillation cleaning on the surface of the composite material sheet.

[0025] Beneficial effects: This solution adopts the above-mentioned method. The high-frequency vibration generated by ultrasonic oscillation allows the solvent to quickly penetrate into the tiny crevices of the surface, effectively removing oil and grease impurities. Compared with traditional cleaning methods, it is more thorough and efficient. Moreover, the gentle action of ultrasonic waves will not damage the surface of aluminum-tin alloy, and can retain surface activity to the greatest extent. The whole process surface treatment further improves surface activity and roughness, and solves the problem of coating peeling.

[0026] Preferably, as an improvement, in step four, the sandblasting process involves drying the cleaned composite material sheet and then sandblasting it with Al2O3 particles, resulting in a surface roughness of Ra = 0.8~1.2 for the composite material sheet after sandblasting.

[0027] Beneficial effects: The above-mentioned solution uses pre-blasting drying to avoid residual moisture affecting the blasting effect and subsequent coating adhesion; the Al2O3 particles have moderate hardness and good wear resistance, which can accurately shape the surface morphology during blasting and are not prone to leaving impurities; and by controlling the surface roughness to Ra=0.8~1.2, the mechanical interlocking between the coating and the substrate can be maximized, which not only ensures the coating is firmly attached, but also avoids stress concentration caused by excessive roughness that will damage the integrity of the coating, while strengthening the surface properties of aluminum-tin alloy, laying a good foundation for the preparation of subsequent functional coatings.

[0028] Preferably, as an improvement, in step five, the preheating temperature is 60~80 ℃.

[0029] Beneficial effects: The above-mentioned solution can effectively improve the surface activity of the substrate and the interfacial compatibility of the coating, avoid the thermal stress caused by excessive temperature difference between the substrate and the coating, which can lead to cracking or peeling of the coating, and prevent the performance degradation of aluminum-tin alloy due to excessive temperature. It balances the interfacial bonding effect and the stability of the substrate material.

[0030] Preferably, as an improvement, in step five, the thickness of the coating obtained by polymer spraying is 10~15 μm.

[0031] Beneficial effects: The above-mentioned solution facilitates the balance between protective performance and mechanical compatibility. It can fully utilize the wear resistance and corrosion resistance of polymer materials, effectively isolate the substrate from external media erosion, and avoid problems such as residual internal stress and reduced flexibility caused by excessive coating thickness. It ensures that the coating and the substrate work together to bear the force, thereby improving the overall service life of the composite material.

[0032] Preferably, as an improvement, in step five, the curing process includes the following: first heating to 50~70℃ and holding for 60 min; then heating to 110~130℃ and holding for 60 min; then heating to 170~190℃ and holding for 60 min; and finally heating to 230~250℃ and holding for 60 min.

[0033] Beneficial Effects: This solution employs the aforementioned method. The stepped heating during curing avoids the rapid evaporation of solvents within the coating, preventing defects such as bubbles and pinholes caused by rapid heating, thus ensuring coating density. Sufficient holding time at each stage allows the coating components to fully react and cure uniformly, gradually increasing the coating's crosslinking density and mechanical strength. The final high-temperature stage of 230-250 °C ensures complete curing, while remaining within the performance stability range of aluminum-tin alloys and low-carbon steel, preventing damage to the substrate material and achieving dual protection of coating performance and substrate stability. Through long-term experiments, the inventors discovered that without stepped heating, rapid heating prevents the complete escape of gases from the coating, significantly increasing internal defects and worsening the coating's bonding strength and surface finish. However, using a two- to three-stage gradient heating process allows sufficient time for gas escape, significantly reducing internal defects and improving coating adhesion and performance stability. If the holding time for each temperature level is too long, the polymer chains will undergo excessive cross-linking or thermal degradation when the holding time exceeds the optimal window period, leading to a loss of toughness or cracking of the coating. Conversely, if the holding time for each temperature level is too short, the chemical reaction will not be able to proceed completely, resulting in an unstable physical state of the coating and significantly reducing the adhesion and mechanical properties of the coating material.

[0034] Preferably, as an improvement, in step five, the cooling process includes the following: first cooling to 170~190 ℃ and holding for 60 min; then cooling to 110~130 ℃ and holding for 60 min; then cooling to 50~70 ℃ and holding for 60 min; and finally cooling to room temperature.

[0035] Beneficial Effects: This solution employs the aforementioned method, where the stepped cooling during cooling and the stepped heating during curing complement each other, avoiding excessive thermal stress between the coating and substrate caused by rapid cooling, thus preventing defects such as cracking and peeling. Sufficient holding time at each stage allows for uniform temperature conduction within the material, gradually releasing residual internal stress from curing and rolling, and improving the overall dimensional stability of the composite material. Finally, slow cooling to room temperature further ensures the strong bond between the coating and substrate, while preventing structural distortion of the substrate material due to sudden cooling, ensuring balanced and stable mechanical properties of the composite material. Through long-term experiments, the inventors discovered that without stepped cooling, rapid cooling leads to significant residual stress within the coating, significantly increasing internal defects and affecting its mechanical properties. However, using two to three stages of gradient cooling significantly reduces residual stress due to the sufficient cooling process, preventing cracking, blistering, and peeling, and improving the coating's mechanical properties. If the holding time at each temperature stage is too long, prolonged exposure to high temperatures can cause aging or discoloration of the coating, significantly reducing the mechanical properties of the coating material. If the holding time for each temperature level is too short, the surface of the workpiece will cool and shrink rapidly while the interior remains at a high temperature, resulting in huge internal stress that causes the coating to peel off, blister, and significantly reduces the adhesion of the coating material.

[0036] Preferably, as an improvement, this solution also provides a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material, including the composite material prepared by the above method.

[0037] Beneficial effects: The polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and its preparation method provided in this solution are simple in equipment and easy to modify. They can effectively reduce the initial pressure of rolling composite, reduce the rolling mill load, extend the rolling mill service life, and enable continuous and large-scale mass production of composite material plates. Attached Figure Description

[0038] Figure 1 The metallographic structure of the aluminum-tin alloy-low carbon steel composite material plate obtained in Example 1 of the present invention is shown.

[0039] Figure 2 The metallographic structure of the aluminum-tin alloy-low carbon steel composite material plate obtained in Comparative Example 1 of this invention is shown.

[0040] Figure 3 The metallographic structure of the aluminum-tin alloy-low carbon steel composite material plate obtained in Comparative Example 2 of this invention is shown.

[0041] Figure 4 The Vickers hardness of the aluminum-tin alloy-low carbon steel composite material sheet obtained in Example 1 of this invention.

[0042] Figure 5The Vickers hardness of the aluminum-tin alloy-low carbon steel composite material sheet obtained in Comparative Example 1 of this invention is shown.

[0043] Figure 6 The Vickers hardness of the aluminum-tin alloy-low carbon steel composite material sheet obtained in Comparative Example 2 of this invention is given. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following embodiments and experimental examples are conventional means well known to those skilled in the art, and the materials and reagents used can all be obtained commercially.

[0045] Example 1

[0046] This embodiment provides a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and its preparation method, including the following steps:

[0047] Step 1: Rivet 0.5mm thick pure aluminum, 2.0mm thick aluminum-tin alloy (AlSn20Cu alloy) and 0.5mm thick pure aluminum together to form a composite billet. Perform multi-pass room temperature rolling (the first pass has a reduction of 40%, and each subsequent pass has a reduction of 8%) and a first heat treatment (treated at 300℃ for 75 minutes, followed by annealing). After the composite billet cools to room temperature, a pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet is obtained.

[0048] Step 2: Fix 0.5mm thick pure aluminum foil to the surface of 10.0mm thick low carbon steel plate by riveting, and perform one room temperature rolling (with a reduction of 10%) and a second heat treatment (heat treatment at 400℃ for 45min) to obtain pure aluminum / low carbon steel composite material plate.

[0049] Step 3: Rivet the heat-treated pure aluminum / aluminum-tin alloy / pure aluminum composite sheet (rolling temperature at room temperature) and the pure aluminum / low carbon steel composite sheet (rolling temperature at 500℃, rolling reduction of 45%) to form a composite billet (pure aluminum-aluminum-tin alloy-pure aluminum + pure aluminum-low carbon steel sheet), perform heterothermal rolling and a third heat treatment (treated at 350℃ for 150 min, followed by annealing), and wait for the composite billet to cool to room temperature to obtain the aluminum-tin alloy-low carbon steel composite sheet;

[0050] Step 4: Remove the pure aluminum layer from the aluminum-tin alloy surface of the aluminum-tin alloy-low carbon steel composite material sheet, and perform degreasing and degreasing treatment on the surface of the composite material sheet (using an ultrasonic cleaning process with a solvent; for reference, the solvent in this solution is anhydrous ethanol), sandblasting (drying the cleaned composite material sheet, and then sandblasting it with Al2O3 particles; the surface roughness of the composite material sheet after sandblasting is Ra=0.8~1.2), and cleaning (using an ultrasonic cleaning process with a solvent on the surface of the composite material sheet).

[0051] Step 5: Preheat the surface of the aluminum-tin alloy-low carbon steel composite material sheet (70℃), apply polymer spraying (the thickness of the polymer spraying coating is 10~15μm; in practice, any polymer coating raw material composition commonly used in this industry can be used. As a reference, the polymer coating prepared by spraying in this scheme has the following composition and mass percentage: 60% polyimide, 15% molybdenum disulfide, 10% graphite, 8% boron nitride, and 7% polyetheretherketone binder; during construction, surface spraying is carried out using automated or handheld equipment), cure treatment (heat to 60℃ and hold for 60min; heat to 120℃ and hold for 60min; heat to 180℃ and hold for 60min; heat to 240℃ and hold for 60min), and staged cooling treatment (cool to 180℃ and hold for 60min; cool to 120℃ and hold for 60min; cool to 60℃ and hold for 60min; cool to room temperature) to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material sheet.

[0052] Example 2

[0053] This embodiment provides a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and its preparation method, including the following steps:

[0054] Step 1: Rivet 0.5mm thick pure aluminum, 2.0mm thick aluminum-tin alloy (AlSn20Cu alloy) and 0.5mm thick pure aluminum together to form a composite billet. Perform multi-pass room temperature rolling (the first pass has a reduction of 40%, and each subsequent pass has a reduction of 10%) and a first heat treatment (treated at 250℃ for 90 minutes, followed by annealing). After the composite billet cools to room temperature, a pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet is obtained.

[0055] Step 2: Fix 0.5mm thick pure aluminum foil to the surface of 10.0mm thick low carbon steel plate by riveting, and perform one room temperature rolling (with a reduction of 10%) and a second heat treatment (heat treatment at 450℃ for 40min) to obtain pure aluminum / low carbon steel composite material plate.

[0056] Step 3: Rivet the heat-treated pure aluminum / aluminum-tin alloy / pure aluminum composite sheet (rolling temperature at room temperature) and the pure aluminum / low carbon steel composite sheet (rolling temperature at 450℃, rolling reduction of 40%) to form a composite billet (pure aluminum-aluminum-tin alloy-pure aluminum + pure aluminum-low carbon steel sheet), perform heterothermal rolling and a third heat treatment (treated at 300℃ for 210 min, followed by annealing), and wait for the composite billet to cool to room temperature to obtain the aluminum-tin alloy-low carbon steel composite sheet;

[0057] Step 4: Remove the pure aluminum layer from the aluminum-tin alloy surface of the aluminum-tin alloy-low carbon steel composite material sheet, and perform degreasing and degreasing treatment on the surface of the composite material sheet (using an ultrasonic cleaning process with a solvent; for reference, the solvent in this solution is anhydrous ethanol), sandblasting (drying the cleaned composite material sheet, and then sandblasting it with Al2O3 particles; the surface roughness of the composite material sheet after sandblasting is Ra=0.8~1.2), and cleaning (using an ultrasonic cleaning process with a solvent on the surface of the composite material sheet).

[0058] Step 5: Preheat the surface of the aluminum-tin alloy-low carbon steel composite material sheet (60℃), apply polymer spraying (the thickness of the polymer spraying coating is 10~15μm; in practice, any polymer coating raw material composition commonly used in this industry can be used. As a reference, the polymer coating prepared by spraying in this scheme has the following composition and mass percentage: 60% polyimide, 15% molybdenum disulfide, 10% graphite, 8% boron nitride, and 7% polyetheretherketone binder; during construction, surface spraying is carried out using automated or handheld equipment), cure treatment (heat to 50℃ and hold for 60 min; heat to 110℃ and hold for 60 min; heat to 170℃ and hold for 60 min; heat to 230℃ and hold for 60 min), and staged cooling treatment (cool to 170℃ and hold for 60 min; cool to 110℃ and hold for 60 min; cool to 50℃ and hold for 60 min; cool to room temperature) to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material sheet.

[0059] Example 3

[0060] This embodiment provides a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material and its preparation method, including the following steps:

[0061] Step 1: Rivet 0.5mm thick pure aluminum, 2.0mm thick aluminum-tin alloy (AlSn20Cu alloy) and 0.5mm thick pure aluminum together to form a composite billet. Perform multi-pass room temperature rolling (the first pass has a reduction of 40%, and each subsequent pass has a reduction of 9%) and a first heat treatment (treated at 350℃ for 60 minutes, followed by annealing). After the composite billet cools to room temperature, a pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet is obtained.

[0062] Step 2: Fix 0.5mm thick pure aluminum foil to the surface of 10.0mm thick low carbon steel plate by riveting, and perform one room temperature rolling (with a reduction of 10%) and a second heat treatment (heat treatment at 500℃ for 30 minutes) to obtain pure aluminum / low carbon steel composite material plate.

[0063] Step 3: Rivet the heat-treated pure aluminum / aluminum-tin alloy / pure aluminum composite sheet (rolling temperature at room temperature) and the pure aluminum / low carbon steel composite sheet (rolling temperature at 550℃, rolling reduction of 50%) to form a composite billet (pure aluminum-aluminum-tin alloy-pure aluminum + pure aluminum-low carbon steel sheet), perform heterothermal rolling and a third heat treatment (treated at 320℃ for 180 min, followed by annealing), and wait for the composite billet to cool to room temperature to obtain the aluminum-tin alloy-low carbon steel composite sheet;

[0064] Step 4: Remove the pure aluminum layer from the aluminum-tin alloy surface of the aluminum-tin alloy-low carbon steel composite material sheet, and perform degreasing and degreasing treatment on the surface of the composite material sheet (using an ultrasonic cleaning process with a solvent; for reference, the solvent in this solution is anhydrous ethanol), sandblasting (drying the cleaned composite material sheet, and then sandblasting it with Al2O3 particles; the surface roughness of the composite material sheet after sandblasting is Ra=0.8~1.2), and cleaning (using an ultrasonic cleaning process with a solvent on the surface of the composite material sheet).

[0065] Step 5: Preheat the surface of the aluminum-tin alloy-low carbon steel composite material sheet (80℃), apply polymer spraying (the thickness of the polymer spraying coating is 10~15μm; in practice, any polymer coating raw material composition commonly used in this industry can be used. As a reference, the polymer coating prepared by spraying in this scheme has the following composition and mass percentage: 60% polyimide, 15% molybdenum disulfide, 10% graphite, 8% boron nitride, and 7% polyetheretherketone binder; during construction, surface spraying is carried out using automated or handheld equipment), cure treatment (heat to 70℃ and hold for 60min; heat to 130℃ and hold for 60min; heat to 190℃ and hold for 60min; heat to 250℃ and hold for 60min), and staged cooling treatment (cool to 190℃ and hold for 60min; cool to 130℃ and hold for 60min; cool to 70℃ and hold for 60min; cool to room temperature) to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material sheet.

[0066] Comparative Example 1

[0067] This comparative example is basically the same as Example 1, except that in step three, a structure of "pure aluminum-aluminum-tin alloy-pure aluminum + low carbon steel plate" is formed during riveting.

[0068] Comparative Example 2

[0069] This comparative example is basically the same as Example 1, except that: in step one, the first pass of the multi-pass room temperature rolling has a reduction of 40%, and the subsequent passes have a reduction of 5%.

[0070] Comparative Example 3

[0071] This comparative example is basically the same as Example 1, except that in step four, the surface roughness of the composite material sheet after sandblasting is Ra=0.5.

[0072] Comparative Example 4

[0073] This comparative example is basically the same as Example 1, except that in step four, the surface roughness of the composite material sheet after sandblasting is Ra=1.5.

[0074] Comparative Example 5

[0075] This comparative example is basically the same as Example 1, except that: in step five, no polymer coating is sprayed.

[0076] Comparative Example 6

[0077] This comparative example is basically the same as Example 1, except that in step five, a two-stage gradient heating is used: first, the temperature is heated to 90°C and held for 120 minutes; then, it is heated to 220°C and held for 120 minutes.

[0078] Comparative Example 7

[0079] This comparative example is basically the same as Example 1, except that in step five, a three-stage gradient heating is used: first, heat to 80°C and hold for 60 minutes; then heat to 150°C and hold for 90 minutes; finally, heat to 240°C and hold for 90 minutes.

[0080] Comparative Example 8

[0081] This comparative example is basically the same as Example 1, except that in step five, the following cooling method is used: first cool to 150°C and keep warm for 90 minutes; then cool to 80°C and keep warm for 90 minutes; then cool to room temperature.

[0082] Comparative Example 9

[0083] This comparative example is basically the same as Example 1, except that natural cooling is used in step five.

[0084] Experimental Example: Performance Testing

[0085] The performance of the polymer coating-aluminum-tin alloy-low-carbon steel multi-element sliding bearing composite materials prepared in Example 1 and Comparative Examples 1-9 was tested. The tests included the following:

[0086] 1. Performance testing of aluminum-tin alloy-low carbon steel composite sheet

[0087] The metallographic structure of the aluminum-tin alloy-low carbon steel composite plates prepared in step three of Examples 1, Comparative Example 1, and Comparative Example 2 was analyzed according to GB / T 13298-2015 "Methods for Examination of Metallic Microstructures". The results are as follows: Figures 1-3 As shown. Figure 1 The metallographic structure of Example 1 is shown. Figure 2 The metallographic structure of Comparative Example 1 is shown. Figure 3 The metallographic structure of Comparative Example 2 is shown.

[0088] The bonding strength of the aluminum-tin alloy-low carbon steel composite plates obtained in Example 1, Comparative Example 1, and Comparative Example 2 was tested in accordance with GB / T 18329.2-2023 "Sliding bearings - Multilayer metal sliding bearings - Part 2: Destructive test of bonding strength for alloys with a thickness ≥2 mm". The results are shown in Table 1.

[0089] The porosity of the aluminum-tin alloy-low carbon steel composite plates obtained in Example 1, Comparative Example 1, and Comparative Example 2 was tested according to GB / T 13298-2015 "Methods for Testing the Microstructure of Metals". The results are shown in Table 1.

[0090] The Vickers hardness of Example 1, Comparative Example 1, and Comparative Example 2 were tested according to GB / T 4340.1-2009 "Metallic materials - Vickers hardness test - Part 1: Test method". The results are shown in Table 1.

[0091] Table 1. Performance comparison of aluminum-tin alloy-low carbon steel composite plates obtained in Example 1, Comparative Example 1, and Comparative Example 2

[0092]

[0093] Data shows that in Example 1 of this solution, the "pure aluminum-aluminum-tin alloy-pure aluminum + pure aluminum-low carbon steel sheet" structure formed during riveting effectively acts as a barrier to prevent direct contact between pure aluminum and carbon steel, allowing the hard aluminum-tin alloy and the mild steel to better coordinate deformation (comparison). Figures 1-3 This process inhibits the formation of brittle intermetallic compounds, thereby improving shear bond strength and service reliability. However, if the riveting process forms a structure of "pure aluminum-aluminum-tin alloy-pure aluminum + low-carbon steel sheet" (as in Comparative Example 1), the pure aluminum is prone to reacting with the carbon steel to form brittle intermetallic compounds, resulting in low bond strength. Furthermore, if the first pass of the multi-pass room temperature rolling in step one has a reduction of 40%, and each subsequent pass has a reduction of 5% (as in Comparative Example 2), the excessively low reduction in each subsequent pass leads to significant precipitation of tin due to excessive deformation, and also results in insufficient refinement of the interlayer structure, thus reducing bond strength.

[0094] 2. Composite material performance testing

[0095] The surface roughness of the polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite materials prepared in Example 1 and Comparative Examples 3 to 9 was tested according to GB / T 7220-2004 "Technical Specification for Geometric Measurement of Products (GPS) - Surface Structure Profile Method - Terminology and Parameter Measurement of Surface Roughness". The results are shown in Table 2.

[0096] The coating adhesion of the composite materials obtained in Example 1 and Comparative Examples 3 to 9 was tested according to the GB / T 9286-2021 standard "Cross-cut test for paints and varnishes". The results are shown in Table 2.

[0097] The coating hardness of the composite materials obtained in Example 1 and Comparative Examples 3 to 9 was tested according to ISO 15184-2012 "Paints and varnishes - Determination of film hardness by pencil test". The results are shown in Table 2.

[0098] The tribological properties of the composite materials obtained in Example 1 and Comparative Examples 3 to 9 were tested according to GB / T 35083.1-2018 "Tribological Properties Test of Sliding Bearing Materials - Part 1: Test of Metal Bearing Materials". The results are shown in Table 2.

[0099] Table 2 Comparison of composite material performance tests in Example 1 and Comparative Examples 3 to 9

[0100]

[0101] Data shows that this solution effectively improves the overall performance of the composite material by combining measures such as limiting the surface roughness of the aluminum-tin alloy-low carbon steel composite sheet and the heating and cooling processes after spraying the polymer material. This solves the technical problem of low strength and degraded wear resistance of the aluminum-tin alloy itself, which prevents the synergistic optimization of overall performance. However, if the surface roughness is too low (as in Comparative Example 3), the improvement in composite material performance is very limited, but it increases processing costs. If the surface roughness is too high (as in Comparative Example 4), it easily leads to stress concentration, damaging the coating integrity and causing pitting on the coating surface. If no polymer coating is sprayed (as in Comparative Example 5), although the material's properties are significantly improved, its coefficient of friction also increases significantly, reducing the wear resistance of the multi-element sliding bearing composite material. If, after spraying polymer materials, two-stage gradient heating curing (as in Comparative Example 6), three-stage gradient heating curing (as in Comparative Example 7), two-stage gradient cooling (as in Comparative Example 8), or natural cooling (as in Comparative Example 9) are used, the surface roughness and friction coefficient of the composite material will increase, reducing its wear resistance. Furthermore, due to excessively rapid heating / cooling, defects such as ripples and / or pitting will appear on the surface of the polymer coating, reducing its service life.

[0102] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material, characterized in that: Includes the following steps: Step 1: Rivet pure aluminum, aluminum-tin alloy, and pure aluminum together to form a composite billet, perform multi-pass room temperature rolling and a first heat treatment, and after the composite billet cools to room temperature, obtain a pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet; the first pass of the multi-pass room temperature rolling has a reduction of 40%, and the reduction of each subsequent pass is 8~10%; the first heat treatment is performed at 250~350℃ for 60~90 min, followed by annealing. Step 2: Fix the pure aluminum foil to the surface of the low carbon steel plate by riveting, and perform a room temperature rolling and a second heat treatment to obtain the pure aluminum / low carbon steel composite material plate. Step 3: Rivet the heat-treated pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet and the pure aluminum / low carbon steel composite material sheet to form a composite billet, perform differential temperature rolling and a third heat treatment, and wait for the composite billet to cool to room temperature to obtain the aluminum-tin alloy-low carbon steel composite material sheet. Step 4: Remove the pure aluminum layer from the aluminum-tin alloy surface of the aluminum-tin alloy-low carbon steel composite material sheet, and perform degreasing, degreasing, sandblasting, and cleaning treatment on the surface of the composite material sheet; the sandblasting treatment step is to dry the cleaned composite material sheet, and then use Al2O3 particles for sandblasting. After sandblasting, the surface roughness of the composite material sheet is Ra=0.8~1.

2. Step 5: Preheat, polymer spray, cure and segmented cooling are performed on the surface of the aluminum-tin alloy-low carbon steel composite material sheet to obtain the polymer coating-aluminum-tin alloy-low carbon steel composite material sheet. The curing process includes the following steps: first, heating to 50~70℃ and holding for 60 min; then heating to 110~130℃ and holding for 60 min; then heating to 170~190℃ and holding for 60 min; finally heating to 230~250℃ and holding for 60 min. The cooling process includes the following steps: first cooling to 170~190℃ and holding for 60 min; then cooling to 110~130℃ and holding for 60 min; then cooling to 50~70℃ and holding for 60 min; and finally cooling to room temperature.

2. The preparation method of a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material according to claim 1, characterized in that: In step two, the reduction in the first-pass room temperature rolling is 10%; the second heat treatment is performed at 400~500℃ for 30~45 min.

3. The preparation method of a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material according to claim 1, characterized in that: In step three, the process parameters for the differential temperature rolling are as follows: the rolling temperature of the pure aluminum / aluminum-tin alloy / pure aluminum composite material sheet is room temperature, the rolling temperature of the pure aluminum / low carbon steel composite material sheet is 450~550℃, and the rolling reduction is 40~50%; the third heat treatment is heat treatment at 300~350℃ for 150~210 min, followed by annealing.

4. The preparation method of a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material according to claim 1, characterized in that: In step four, the degreasing and oil removal process involves using a solvent to perform ultrasonic oscillation cleaning on the surface of the composite material sheet.

5. The preparation method of a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material according to claim 1, characterized in that: In step five, the preheating temperature is 60~80℃.

6. The preparation method of a polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material according to claim 1, characterized in that: In step five, the thickness of the coating obtained by polymer spraying is 10~15μm.

7. A polymer coating-aluminum-tin alloy-low carbon steel multi-element sliding bearing composite material, characterized in that: The composite material prepared by the method according to any one of claims 1 to 6.

Images