A copper-based friction-reducing material, a preparation method and application thereof

Abstract

This invention relates to a copper-based friction-reducing material, its preparation method, and its application, belonging to the technical field of copper-based friction-reducing materials. The chemical composition of the copper-based friction-reducing material is: Sn: 7.2wt%~8.6wt%, Al: 1.8wt%~2.8wt%, Fe: 0.5wt%~1.0wt%, Ni: 0.2wt%~0.6wt%, impurities: <1.5wt%, and the balance is Cu. The preparation method of the copper-based friction-reducing material includes the following steps: a mixed powder formed according to the mass ratio of each element is sequentially shaped, vacuum sintered, and heat-treated to obtain the copper-based friction-reducing material. This invention solves the problem that aluminum-tin bronze is difficult to prepare using sintering processes. The prepared copper-based friction-reducing material has the advantages of high load-bearing capacity, good wear resistance, and good reliability under high specific pressure conditions, and is low in cost, making it suitable for mass production application in heavy-duty diesel engine bearing bushings.

Description

Technical Field

[0001] This invention belongs to the technical field of copper-based friction-reducing materials, specifically relating to a copper-based friction-reducing material, its preparation method, and its application. Background Technology

[0002] Heavy-duty diesel engines, as core components of commercial vehicles, typically operate under conditions of high load, high speed, and long-term continuous operation. Bearing bushings, as critical friction pairs in heavy-duty diesel engines, have material properties that directly determine the engine's reliability and service life.

[0003] Heavy-duty diesel engine bearing bushings generally employ a double-layer composite material, consisting of a steel backing covered with a friction-reducing alloy layer. Existing friction-reducing alloy layer materials commonly use aluminum alloys or copper alloys. The copper alloy is primarily tin bronze containing strengthening elements such as Ni, Pb, P, Bi, and Zn. Material specifications are typically selected based on the operating conditions, choosing a material with load-bearing capacity and wear resistance that matches the requirements. Generally, the severity of operating conditions increases progressively from main bearing bushings to connecting rod upper bearings to connecting rod bushings. For example, for main bearing bushes, aluminum alloys are selected under operating conditions with a specific pressure ≤ 40 MPa; for connecting rod upper bearing bushes, copper alloys, such as CuSn6Bi3 and CuSn5Zn, are selected under operating conditions with a specific pressure of 65~100 MPa; for connecting rod bushings, copper alloys, such as CuSn8Ni and CuPb10Sn10, are selected under operating conditions with a specific pressure ≥ 100 MPa; and for extremely high load-bearing capacity connecting rod bushings (integral bushings), copper alloys, such as CuSn6Ni6, are selected under operating conditions with a specific pressure ≥ 120 MPa. Aluminum alloy composite plates are manufactured using a casting + rolling process, while tin bronze composite plates are manufactured using a casting + rolling process or a powder metallurgy bimetallic sintering process.

[0004] Based on the reliability requirements of the engine assembly, there is still a need to improve the performance of existing anti-friction alloy layer materials, especially for bearing bushes with a specific pressure range of 60~120MPa, which are used in large quantities.

[0005] Aluminum effectively strengthens tin bronze and improves its temperature resistance; however, due to the oxidation properties of aluminum, the processability of aluminum-containing tin bronze deteriorates, making it difficult to use in practice, especially in powder metallurgy sintering processes, where anti-friction alloy layers made of aluminum-containing copper alloys have not yet been developed. Zinc can effectively strengthen copper alloys, but its use in sintered copper alloys is limited by the "zinc volatilization" phenomenon during sintering. Furthermore, the cost-effectiveness of currently used tin bronze strengthened with elements such as Ni and P still has significant room for improvement.

[0006] In summary, how to solve the problem of the difficulty in preparing aluminum-tin bronze using sintering processes, while taking into account the material's load-bearing capacity, wear resistance, and cost control under high specific pressure conditions, is an urgent technical problem to be solved. Summary of the Invention

[0007] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a copper-based anti-friction material, its preparation method and application, so as to solve the problem that aluminum-tin bronze is difficult to prepare by sintering process. At the same time, the prepared copper-based anti-friction material has the advantages of high load-bearing capacity, good wear resistance and good reliability under high specific pressure conditions, and low cost, and is suitable for mass production application in the bearing bushing of heavy-duty diesel engines.

[0008] To achieve the above objectives, the first aspect of the present invention provides a copper-based friction-reducing material, wherein the chemical composition of the copper-based friction-reducing material is as follows (by mass percentage): Sn: 7.2wt%~8.6wt%, Al: 1.8wt%~2.8wt%, Fe: 0.5wt%~1.0wt%, Ni: 0.2wt%~0.6wt%, impurities: <1.5wt%, and the balance being Cu.

[0009] A second aspect of the present invention provides a method for preparing a copper-based anti-friction material as described in the first aspect of the present invention, comprising the following steps: The copper-based anti-friction material is obtained by sequentially shaping, vacuum sintering, and heat treatment of the mixed powder formed according to the mass ratio of each element.

[0010] Preferably, the mixed powder comprises pre-alloyed powder and elemental powder; wherein the pre-alloyed powder is Cu-Al pre-alloyed powder, and the elemental powder comprises Cu powder, Sn powder, Ni powder, and Fe powder.

[0011] Preferably, the average particle size of the mixed powder is 20~150µm.

[0012] Preferably, the forming process includes cold pressing; wherein the pressure of the cold pressing is 300~600MPa.

[0013] Preferably, the vacuum degree of the vacuum sintering process is 5~20 Pa, the temperature is 880~950℃, and the time is 40~70 min.

[0014] Preferably, the heat treatment includes a two-stage rate-controlled cooling process, wherein: The cooling rate in the first stage is 1.5~3.0℃ / s, cooling from the vacuum sintering temperature to the preset temperature; The second stage cooling rate is 0.5~1.0℃ / s, and the product is removed from the furnace after cooling from the preset temperature to room temperature; The preset temperature is 550~600℃.

[0015] Preferably, the two-stage rate-controlled cooling process is carried out in an inert gas atmosphere with a pressure of 1500~3000 Pa.

[0016] Preferably, the heat treatment further includes an aging treatment; wherein the aging treatment is performed at a temperature of 360~400℃ for a time of 2~3 hours.

[0017] The third aspect of the present invention provides the application of a copper-based friction-reducing material as described in the first aspect of the present invention or a copper-based friction-reducing material prepared by the method described in the second aspect of the present invention in the bearing bushing of a heavy-duty diesel engine.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention solves the problem of the difficulty in preparing aluminum-tin bronze by sintering through the regulation of the chemical composition of copper-based anti-friction materials and a specific preparation method. Compared with existing alloy layer materials (such as CuSn8Ni) used for medium- and high-strength requirements (connecting rod bearings, connecting rod bushings), the copper-based anti-friction material prepared by this invention has the advantages of high load-bearing capacity, good wear resistance, and good reliability under high specific pressure conditions (60~120MPa), and is low in cost, making it suitable for mass production application in heavy-duty diesel engine bearing bushings. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Heavy-duty diesel engine bearing bushings generally employ a double-layer composite material, consisting of a steel backing covered with a friction-reducing alloy layer. Currently, the friction-reducing alloy layer materials are commonly aluminum or copper alloys. Based on the reliability requirements of the engine assembly, there is still a need to improve the performance of existing friction-reducing alloy layer materials, especially for bearing bushings designed with a specific pressure range of 60-120 MPa, where the usage is significant.

[0021] Aluminum effectively strengthens tin bronze and improves its temperature resistance; however, due to the oxidation properties of aluminum, the processability of aluminum-containing tin bronze deteriorates, making its practical application difficult, especially in powder metallurgy sintering processes, where anti-friction alloy layers made of aluminum-containing copper alloys have not yet been developed. Zinc (Zn) can effectively strengthen copper alloys, but its use in sintered copper alloys is limited by the "zinc volatilization" phenomenon during sintering. Furthermore, the cost-effectiveness of tin bronze strengthened with elements such as Ni and P currently available still has significant room for improvement.

[0022] In view of this, the present invention provides a copper-based anti-friction material, its preparation method and application, to solve the problem that aluminum-tin bronze is difficult to prepare by sintering process, while taking into account the material's load-bearing capacity, wear resistance and cost control under high specific pressure conditions.

[0023] In a first aspect, embodiments of the present invention provide a copper-based friction-reducing material, wherein the chemical composition of the copper-based friction-reducing material, by mass percentage, is: Sn: 7.2wt%~8.6wt%, Al: 1.8wt%~2.8wt%, Fe: 0.5wt%~1.0wt%, Ni: 0.2wt%~0.6wt%, impurities: <1.5wt%, and the balance is Cu.

[0024] The elements and their synergistic effects in the copper-based anti-friction material provided by this invention are as follows: Sn: Solid solution strengthening and strength enhancement; it can form a friction-reducing phase with self-lubricating properties, reducing the coefficient of friction; it promotes the formation of trace liquid phases, improving densification and sintering alloying properties; Ni: Significantly refines the microstructure, simultaneously increasing both strength and toughness; Al: It can form a hard and brittle phase, which significantly improves hardness, compressive strength, wear resistance, high temperature stability and corrosion resistance; Fe: It has a strong grain-refining effect and can form fine intermetallic compounds, which improves hardness and wear resistance; The elements Sn, Ni, Al, and Fe can also produce a synergistic strengthening effect, which can improve the strength of materials and enhance their load-bearing capacity, wear resistance, and reliability (strength retention rate and corrosion resistance at operating temperature) under high specific pressure conditions.

[0025] Secondly, embodiments of the present invention also provide a method for preparing a copper-based friction-reducing material as described in the first aspect of the present invention, comprising the following steps: The copper-based anti-friction material is obtained by sequentially shaping, vacuum sintering, and heat treatment of the mixed powder formed according to the mass ratio of each element.

[0026] In the preparation method of the copper-based anti-friction material provided by this invention, a mixed powder is first prepared according to the mass ratio of each element. The mixed powder includes pre-alloyed powder and elemental powder. The pre-alloyed powder is Cu-Al pre-alloyed powder (e.g., aluminum bronze pre-alloyed powder, mainly used as a source of Cu and Al), which is the main component of the mixed powder and the sole source of Al. The elemental powder includes Cu powder, Sn powder, Ni powder, and Fe powder. Therefore, in the copper-based anti-friction material provided by this invention, the proportion of copper comes from two sources: firstly, the Cu-Al pre-alloyed powder itself has a definite Al and Cu ratio, thus containing a portion of Cu required for the chemical composition ratio of the anti-friction material; secondly, the remaining Cu required for the chemical composition ratio of the anti-friction material is supplemented by elemental powder Cu powder. This invention uses pre-alloyed powder (atomized alloy powder) as the main component and adds a small amount of elemental powder to form the mixed powder, which is beneficial for improving the forming processability of the mixed powder.

[0027] In some preferred embodiments, the oxygen content of the pre-alloyed powder needs to be less than 0.1% to reduce the impact of Al oxidation on the sintering alloying and densification processes.

[0028] In some preferred embodiments, the average particle size of the mixed powder is 20~150µm.

[0029] In the preparation method of the copper-based anti-friction material provided by this invention, controlling the average particle size of the mixed powder within the above-mentioned range not only enables efficient pressing and forming, which is beneficial for achieving the required density and improving the strength of the green blank, but also enhances the sintering driving force and alloying efficiency. In the preparation method of the copper-based anti-friction material provided by this invention, the forming process includes cold pressing (with a mold). Preferably, the pressure (molding pressure) of the cold pressing is 300~600 MPa.

[0030] In the preparation method of the copper-based anti-friction material provided by this invention, the material after forming is subjected to vacuum sintering. This invention requires strict control of the vacuum sintering conditions to effectively reduce the impact of Al oxidation on the sintering process. In some preferred embodiments, the vacuum degree of the vacuum sintering process is 5~20 Pa, the temperature is 880~950℃, and the time is 40~70 min.

[0031] In the preparation method of the copper-based anti-friction material provided by the present invention, heat treatment is performed after vacuum sintering to further strengthen the material.

[0032] When the heat treatment is carried out in a vacuum sintering furnace, it includes a two-stage rate-controlled cooling process; wherein: The cooling rate in the first stage is 1.5~3.0℃ / s, cooling from the vacuum sintering temperature (including the end value) to the preset temperature (including the end value). The second stage cooling rate is 0.5~1.0℃ / s, and the furnace is removed after cooling from the preset temperature (excluding the extreme value) to room temperature; The preset temperature is 550~600℃.

[0033] In this invention, the first stage of controlled-rate cooling treatment uses a high cooling rate to allow the material to pass through the high-temperature zone quickly, inhibiting grain growth, retaining fine grains, and improving strength; the second stage of controlled-rate cooling treatment uses a low cooling rate, resulting in a eutectoid transformation, which can obtain fine and dispersed hard phase precipitation without forming a continuous network of hard and brittle phases.

[0034] In some preferred embodiments, the two-stage rate-controlled cooling process is carried out in an inert gas atmosphere with a pressure of 1500~3000 Pa.

[0035] In the preparation method of the copper-based anti-friction material provided by the present invention, preferably after the two-stage controlled-rate cooling treatment, the heat treatment further includes aging treatment; wherein the aging treatment temperature is 360~400℃ and the time is 2~3h.

[0036] In this invention, the two-stage controlled-rate cooling process described above yields a composite microstructure with fine grains and dispersed reinforcing phases. Subsequent aging treatment further enhances this structure. Due to the presence of a certain amount of supersaturated solid solution in the matrix from the initial controlled-rate cooling, aging treatment can further induce the precipitation of finer intermetallic phases, achieving multiple strengthening effects of solid solution, fine grains, and dispersion. This further improves the material's strength, hardness, and wear resistance while maintaining a certain level of plasticity and dimensional stability.

[0037] Therefore, this invention further improves the material strength and enhances its load-bearing capacity, wear resistance, and reliability under high specific pressure conditions by controlling the preparation method of the mixed powder, the vacuum sintering conditions, and the heat treatment method, while reducing costs and improving cost-effectiveness.

[0038] Thirdly, embodiments of the present invention also provide the application of copper-based friction-reducing materials as described in the first aspect of the present invention or copper-based friction-reducing materials prepared by the method described in the second aspect of the present invention in the bearing bushings of heavy-duty diesel engines.

[0039] Compared with existing alloy layer materials (such as CuSn8Ni) used for medium-to-high strength requirements (connecting rod bearings, connecting rod bushings), the copper-based anti-friction material provided by this invention has improved load-bearing capacity, wear resistance and reliability when applied to bearing bushings of heavy-duty diesel engines, and is also low in cost.

[0040] Example Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available, all instruments and equipment used are conventional instruments and equipment in the art, and all operating methods used are conventional methods in the art.

[0041] Unless otherwise specified, the percentage content used in the embodiments of the present invention refers to the mass percentage content.

[0042] Example 1 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 8.0wt%, Al: 2.2wt%, Fe: 0.6wt%, Ni: 0.5wt%, impurities: 0.9wt%, and the balance is Cu (87.8wt%).

[0043] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0044] Example 2 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 7.5wt%, Al: 2.8wt%, Fe: 1.0wt%, Ni: 0.3wt%, impurities: 0.9wt%, and the balance is Cu (87.5wt%).

[0045] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0046] Example 3 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 8.0wt%, Al: 2.2wt%, Fe: 0.6wt%, Ni: 0.5wt%, impurities: 0.9wt%, and the balance is Cu (87.8wt%).

[0047] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 400MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0048] Example 4 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 8.0wt%, Al: 2.2wt%, Fe: 0.6wt%, Ni: 0.5wt%, impurities: 0.9wt%, and the balance is Cu (87.8wt%).

[0049] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum furnace at a vacuum degree of 10 Pa and a temperature of 950 °C for 70 min. S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0050] Example 5 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 8.0wt%, Al: 2.2wt%, Fe: 0.6wt%, Ni: 0.5wt%, impurities: 0.9wt%, and the balance is Cu (87.8wt%).

[0051] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 3.0℃ / s, cooling from 900℃ to 600℃ (including the extreme value). In the second stage, the cooling rate is 0.5℃ / s, and the furnace is removed after cooling from 600℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0052] Example 6 The chemical composition of the copper-based anti-friction material provided in this embodiment is as follows: Sn: 8.0wt%, Al: 2.2wt%, Fe: 0.6wt%, Ni: 0.5wt%, impurities: 0.9wt%, and the balance is Cu (87.8wt%).

[0053] The preparation method of the copper-based anti-friction material provided in this embodiment includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 360℃ for 3 hours.

[0054] Comparative Example 1 Commercially available CuSn8Ni (plate), purchased from Shanghai Hewei Industrial Co., Ltd.

[0055] Comparative Example 2 Commercially available high-strength brass (extruded state, hardness ≥140HB) has the following chemical composition: Zn: 35.0wt%; Mn: 2.0wt%; Al: 1.0wt%; Si: 0.9wt%; impurities: 1.0wt%; balance Cu (60.1wt%).

[0056] Comparative Example 3 The chemical composition of the copper-based anti-friction material provided in this comparative example is as follows: Sn: 15.0 wt%, Al: 2.2 wt%, Fe: 0.6 wt%, Ni: 11.0 wt%, impurities: 0.9 wt%, and the balance is Cu (70.3 wt%).

[0057] The preparation method of the copper-based anti-friction material provided in this comparative example includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0058] Comparative Example 4 The chemical composition of the copper-based anti-friction material provided in this comparative example is as follows: Sn: 8.0 wt%, Al: 2.2 wt%, Fe: 0.6 wt%, Ni: 0.5 wt%, impurities: 0.9 wt%, and the balance is Cu (87.8 wt%).

[0059] The preparation method of the copper-based anti-friction material provided in this comparative example includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 250MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0060] Comparative Example 5 The chemical composition of the copper-based anti-friction material provided in this comparative example is as follows: Sn: 8.0 wt%, Al: 2.2 wt%, Fe: 0.6 wt%, Ni: 0.5 wt%, impurities: 0.9 wt%, and the balance is Cu (87.8 wt%).

[0061] The preparation method of the copper-based anti-friction material provided in this comparative example includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum furnace at a vacuum degree of 3 Pa and a temperature of 800 °C for 60 min. S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0062] Comparative Example 6 The chemical composition of the copper-based anti-friction material provided in this comparative example is as follows: Sn: 8.0 wt%, Al: 2.2 wt%, Fe: 0.6 wt%, Ni: 0.5 wt%, impurities: 0.9 wt%, and the balance is Cu (87.8 wt%).

[0063] The preparation method of the copper-based anti-friction material provided in this comparative example includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4. In a vacuum sintering furnace, under an inert gas atmosphere (gas pressure of 2000 Pa), the sintered billet is cooled to room temperature at a controlled rate before being removed from the furnace. The cooling rate is 2.5℃ / s (not divided into two stages). S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 400℃ for 2 hours.

[0064] Comparative Example 7 The chemical composition of the copper-based anti-friction material provided in this comparative example is as follows: Sn: 8.0 wt%, Al: 2.2 wt%, Fe: 0.6 wt%, Ni: 0.5 wt%, impurities: 0.9 wt%, and the balance is Cu (87.8 wt%).

[0065] The preparation method of the copper-based anti-friction material provided in this comparative example includes the following steps: S1, using aluminum bronze (90wt% Cu content, 8wt% Al content) as pre-alloy powder (oxygen content <0.1%, atomized pre-alloy powder form), and Cu powder, Sn powder, Ni powder and Fe powder as elemental powders, a mixed powder was prepared according to the mass ratio of each element in the copper-based anti-friction material (wherein, the aluminum bronze pre-alloy powder contains a portion of Cu required for the ratio, and the insufficient Cu is made up with Cu powder), the average particle size of the mixed powder is 50µm; S2, the prepared mixed powder is cold-pressed under a pressure of 600MPa to obtain a blank; S3, the obtained billet is vacuum sintered in a vacuum sintering furnace at a vacuum degree of 20 Pa and a temperature of 900 °C for 60 min; S4, in a vacuum sintering furnace, under an inert gas atmosphere (gas pressure 2000 Pa), the sintered billet undergoes a two-stage controlled-rate cooling process, wherein: The cooling rate in the first stage is 2.5℃ / s, cooling from 900℃ to 550℃ (including the extreme value); In the second stage, the cooling rate is 0.8℃ / s, and the furnace is removed after cooling from 550℃ (excluding the extreme value) to room temperature; S5, the billet after controlled-speed cooling is subjected to aging treatment at a temperature of 300℃ for 3 hours.

[0066] The performance of the copper-based anti-friction materials prepared in Examples 1-6 and Comparative Examples 1-7 of the present invention was tested, and the results are shown in Tables 1, 2 and 3, respectively.

[0067] Table 1. Test results of physical and mechanical properties

[0068] Table 2. Test Results of Pin-Disc Friction and Wear Test

[0069] Table 3. Test results of wet friction materials

[0070] The performance test results of the examples and comparative examples in Tables 1, 2 and 3 show that the present invention solves the problem of the difficulty in preparing aluminum-tin bronze by sintering through the regulation of the chemical composition of the copper-based anti-friction material and the combination of a specific preparation method. Compared with existing alloy layer materials (such as CuSn8Ni) used for medium and high strength requirements (connecting rod bearings, connecting rod bushings), the copper-based anti-friction material prepared by the present invention has the advantages of high load-bearing capacity, good wear resistance and good reliability. It can be used in high specific pressure conditions and has low cost, making it suitable for mass production application in heavy-duty diesel engine bearing bushings.

[0071] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0072] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0073] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A copper-based friction reducing material, characterized by, The chemical composition of the copper-based anti-friction material, by mass percentage, is as follows: Sn: 7.2wt%~8.6wt%, Al: 1.8wt%~2.8wt%, Fe: 0.5wt%~1.0wt%, Ni: 0.2wt%~0.6wt%, impurities: <1.5wt%, and the balance is Cu.

2. A method for preparing the copper-based anti-friction material as described in claim 1, characterized in that, Includes the following steps: The copper-based anti-friction material is obtained by sequentially shaping, vacuum sintering, and heat treatment of the mixed powder formed according to the mass ratio of each element.

3. The method of producing a copper-based friction reducing material according to claim 2, wherein The mixed powder comprises pre-alloyed powder and elemental powder; wherein the pre-alloyed powder is Cu-Al pre-alloyed powder, and the elemental powder comprises Cu powder, Sn powder, Ni powder, and Fe powder.

4. The method of producing a copper-based friction reducing material according to claim 2, wherein The average particle size of the mixed powder is 20~150µm.

5. The method of claim 2, wherein the copper-based friction reducing material is prepared by the steps of: The forming process includes cold pressing; wherein the pressure of the cold pressing is 300~600MPa.

6. The method of producing a copper-based friction reducing material according to claim 2, wherein The vacuum sintering process is performed at a vacuum level of 5-20 Pa, a temperature of 880-950 °C, and a time of 40-70 min.

7. The method of claim 2, wherein the copper-based friction reducing material is prepared by a process comprising: The heat treatment includes a two-stage rate-controlled cooling process, wherein: The cooling rate in the first stage is 1.5~3.0℃ / s, cooling from the vacuum sintering temperature to the preset temperature; The second stage cooling rate is 0.5~1.0℃ / s, and the product is removed from the furnace after cooling from the preset temperature to room temperature; The preset temperature is 550~600℃.

8. The method of producing a copper-based friction reducing material according to claim 7, characterized in that, The two-stage rate-controlled cooling process is carried out in an inert gas atmosphere with a pressure of 1500~3000 Pa.

9. The method of claim 7, wherein the copper-based friction reducing material is prepared by a process comprising: The heat treatment also includes aging treatment, wherein the aging treatment temperature is 360~400℃ and the time is 2~3h.

10. The application of a copper-based anti-friction material as described in claim 1 or a copper-based anti-friction material prepared by the method described in any one of claims 2 to 9 in the bearing bushing of a heavy-duty diesel engine.

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