Nickel-bismuth-copper alloy-steel bimetallic bearing material, preparation method therefor, and use thereof

Abstract

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Description

Nickel bismuth copper alloy-steel bimetallic bearing material and its preparation method and application TECHNICAL FIELD

[0001] The present application belongs to the technical field of bearing manufacturing, and particularly relates to a nickel bismuth copper alloy-steel bimetallic bearing material and its preparation method and application. BACKGROUND

[0002] The copper alloy-steel bimetallic bearing material is mainly used for manufacturing sliding bearings of engines, generators and the like. With the improvement of environmental protection requirements and the substantial increase of the strength and bending strength requirements of high-load high-speed generators and engines on sliding bearings, lead-containing bearing materials have been unable to meet the requirements, and therefore the market demand for lead-free and high-performance bearing materials is increasing.

[0003] Since the copper alloy-steel bimetallic bearing material mainly plays a role in supporting and transmitting power, it is required to have strong load-carrying capacity, good friction-reducing and wear-resistant performance and excellent compliance in many occasions. At present, the domestic copper alloy-steel bimetallic bearing material is mainly produced by a powder metallurgy sintering process, and the copper alloy-steel bimetallic bearings produced at home and abroad mainly contain lead. Lead plays a lubricating role in the use of bearings, but lead is separately filled in the alloy, resulting in low strength and bending strength of the alloy, which cannot meet the requirements of high-load and high-speed bearings. The bending strength of the existing copper-lead alloy sliding bearing bimetallic material is 125-140 MPa, and the tensile strength is 260-300 MPa, which cannot meet the high market demand.

[0004] The preparation of the nickel bismuth copper alloy-steel bimetallic bearing material has the following technical problems: (1) the addition of nickel and bismuth can change the mechanical properties of copper, such as hardness, strength and ductility, but at the same time affect the change of the thermal expansion coefficient. (2) The friction coefficient of the nickel bismuth copper alloy may be different from that of pure copper or conventional nickel copper alloy. The change of bismuth content will affect the microstructure and surface roughness of the alloy, and further affect the friction behavior between the contact surfaces. (3) In the manufacture of bimetallic bearings, the metallurgical bonding between the nickel bismuth copper alloy and the steel material is a key problem. If the chemical reaction between the two is violent or incompatible, it may cause the bonding interface to be unstable, affecting the overall mechanical properties and service life of the bearing.

[0005] Based on the technical defects in the prior art, it is of great application prospect and market value to develop a nickel bismuth copper alloy-steel bimetallic bearing material with excellent comprehensive performance.

[0006] SUMMARY

[0007] The present application aims at the defects of low bending strength, poor mechanical load capacity and lead content of copper-lead alloy-steel bimetal bearing material used in high-speed and high-load engines and generators, and provides a nickel-bismuth-copper alloy-steel bimetal bearing material and a preparation method thereof.

[0008] To achieve the above object, the present application provides the following technical solutions.

[0009] A nickel-bismuth-copper alloy-steel bimetal bearing material, wherein a nickel-bismuth-copper alloy powder is sintered on the surface of a carbon steel material with carbon content ≤0.25% under the protection of hydrogen and nitrogen by a high-temperature sintering furnace, and the nickel-bismuth-copper alloy-steel bimetal bearing material is prepared through multiple sintering and rolling; wherein the chemical composition of the nickel-bismuth-copper alloy powder is as follows in terms of weight percentage: nickel 1.5-3.0%, tin 1-2.5%, bismuth 1-3%, silicon carbide 0.2-1%, titanium diboride 0.5-1.5%, lead ≤0.1%, total amount of other impurities ≤1.5%, and the balance being copper.

[0010] Further, the chemical composition of the nickel-bismuth-copper alloy powder is as follows in terms of weight percentage: nickel 1.6-2.4%, tin 1.5-2.0%, bismuth 1.5-2.5%, silicon carbide 0.4-0.7%, titanium diboride 0.8-1.2%, lead ≤0.1%, total amount of other impurities ≤0.5%, and the balance being copper.

[0011] Further, the particle diameter distribution of the nickel-bismuth-copper alloy powder is as follows in terms of weight percentage: -140 mesh~+200 mesh content 0.2-5%; -200 mesh~+325 mesh content 30-45%; and -325 mesh content 50-85%, relative to the total weight 100% of the nickel-bismuth-copper alloy powder.

[0012] In the present application, -325 mesh means that the nickel-bismuth-copper alloy powder can pass through a 325 mesh screen, -200 mesh to +325 mesh means that the nickel-bismuth-copper alloy powder cannot pass through a 325 mesh screen, but can pass through a 200 mesh screen, and -140 mesh to +200 mesh means that the nickel-bismuth-copper alloy powder cannot pass through a 200 mesh screen, but can pass through a 140 mesh screen. By introducing specific contents of nickel, tin and bismuth into the copper-based bearing material, as well as titanium diboride and silicon carbide, the present application can improve the bending strength and tensile strength of the bimetallic bearing material. The inventors have unexpectedly found that the friction of the bimetallic bearing material is also improved. By compounding specific contents of nickel, tin and bismuth, the inventors have found that the three elements reach an ideal balance point in the copper-based material, so that the material has good mechanical strength. When the contents of the three elements are too low, the improvement in the performance of the material is not obvious. When the content of bismuth is too high, bismuth tends to be distributed at the grain boundaries of the nickel-bismuth-copper alloy, and the aggregation of too many brittle phases can cause them to fall off directly from the nickel-bismuth-copper alloy matrix, thereby reducing the friction-reducing effect of bismuth. Too high a content of nickel can lead to unstable microstructure. Too high a content of tin can cause the material to be too soft, thereby greatly reducing the load-carrying capacity and wear resistance of the bearing. Titanium diboride and silicon carbide form hard particles that are dispersed in the copper matrix, which can effectively hinder or disperse the plastic flow of the matrix material under stress. The synergistic effect of the several materials improves the tensile strength and bending strength of the material. However, the inventors have found that the temperature-resistant stability of the bimetallic bearing under different temperatures is not ideal under this condition.

[0013] Further, the particle size distribution of the nickel-bismuth-copper alloy powder is as follows: the content of -140 mesh to +200 mesh is 0.2-2%, the content of -200 mesh to +325 mesh is 35-45%, and the content of -325 mesh is 50-75%, based on 100% by weight of the total weight of the nickel-bismuth-copper alloy powder.

[0014] Further, the titanium diboride is a compound of titanium diboride with a particle size of 1-3 μm, a particle size of 15-20 μm, and a particle size of 30-40 μm, in a weight ratio of 1:0.3-0.7:1.4-1.8.

[0015] Further, the silicon carbide is a compound of silicon carbide with a particle size of 2 μm, a particle size of 10 μm, and a particle size of 45 μm, in a weight ratio of 0.4-0.8:1:0.8-1.2.

[0016] The inventors improve the friction stability of the bimetallic bearing at different temperatures by adding titanium diboride and silicon carbide with different particle sizes. Analysis is that titanium diboride and silicon carbide have very high thermal stability and can maintain their original performance at high temperatures. By compounding titanium diboride and silicon carbide with different particle sizes, a better synergistic effect between them and the copper matrix can be achieved, which can offset part of the internal stress caused by thermal expansion, thereby avoiding material interface separation caused by thermal stress and maintaining the stability of the friction performance.

[0017] Further, the weight ratio of the silicon carbide and titanium diboride is 1:1-2.5.

[0018] In the present application, the weight ratio of the silicon carbide and titanium diboride is 1:1-2.5. From the perspective of better achieving the effect of the present application, the lower limit of the weight ratio of the silicon carbide and titanium diboride is preferably 1.1, more preferably 1.5, further preferably 1.8, and in addition, the upper limit of the weight ratio is preferably 2.4, more preferably 2.3, further preferably 2.2, and particularly preferably 2.

[0019] The inventors unexpectedly found that when the weight ratio of silicon carbide and titanium diboride is 1:1-2.5, the linear expansion coefficient of the bimetallic bearing can be improved. Analysis is that when the particle sizes of silicon carbide and titanium diboride are different, the interface area in contact with the copper matrix will be different, affecting the interface constraint effect, and then affecting the thermal expansion behavior of the entire bearing material. Under this ratio condition, the thermal conductivity efficiency can be improved, and the dimensional stability of the bearing material when heated can be improved.

[0020] The present application also provides a preparation method of the nickel-bismuth-copper alloy-steel bimetallic bearing material, which comprises the following steps:

[0021] (1) Accurately weigh the chemical composition of the nickel-bismuth-copper alloy powder according to the weight percentage, mix and melt, and then use a fully enclosed high-pressure water atomization method to prepare the powder. According to the particle diameter distribution requirements of the nickel-bismuth-copper alloy powder, sieve to obtain the nickel-bismuth-copper alloy powder;

[0022] (2) Cut the carbon content ≤0.25% carbon steel sheet to a specified width, level it after rolling, and then treat the surface. Uniformly coat a layer of nickel-bismuth-copper alloy powder on the surface of the carbon steel sheet;

[0023] (3) Initial firing: sintering under a hydrogen and nitrogen protective atmosphere, the heating rate is 60-70℃ / h, the sintering temperature is 900-1000℃, and the holding time is 15-200 minutes;

[0024] (4) rough rolling: the material after the first sintering in step (3) is rolled to a specified thickness at room temperature in a rolling mill, and the rolling thickness precision is controlled within ±0.01mm; the alloy layer density after rolling is 8.8-8.95g / cm 3 ;

[0025] (5) resintering: the sintering is performed again under the protection of hydrogen and nitrogen atmosphere, the heating rate is 70-80℃ / h, the sintering temperature is 900-950℃, and the holding time is 15-200 minutes, to obtain the resintered steel plate;

[0026] (6) annealing treatment: the resintered steel plate is subjected to annealing treatment under the protection of hydrogen and nitrogen atmosphere, the annealing temperature is 450-500℃, and the annealing time is 50-60 minutes;

[0027] (7) finish rolling and leveling: the material after the annealing treatment is rolled again at room temperature after cooling, to a specified thickness, and the rolling precision is controlled within ±0.01mm, and the alloy layer density after rolling is 8.9-8.95g / cm 3 .

[0028] It should be noted that the high pressure range of the fully-closed high-pressure water atomization method in the present application is set according to specific equipment. The fully-closed high-pressure water atomization method of the present application can be but is not limited to using the water atomization metal powder making machine of Shenzhen Baofeng Precious Metal Equipment Technology Co., Ltd., and the high pressure is 380V.

[0029] Further, the thickness of the steel plate as the raw material in step (2) ranges from 0.5mm to 50.0mm, and the thickness of the nickel-bismuth-copper alloy powder ranges from 0.25mm to 3.0mm.

[0030] Further, the first sintering and the resintering are both performed in a sintering furnace.

[0031] Further, the sintering furnace is a mesh belt type continuous sintering furnace.

[0032] The present application improves the wear resistance of the bearing by using specific first sintering, resintering and annealing conditions. It is analyzed that the first sintering, resintering and annealing play a synergistic role with each other, affect the metallurgical bonding quality between the specific proportion of nickel-bismuth-copper alloy and the steel material of the present application, and further affect the performance of the steel material. The first sintering makes the copper alloy powder form a combined layer with certain strength and tightness on the steel matrix, forms appropriate metallurgical bonding, on this basis, the resintering further ensures the close combination of the nickel-bismuth-copper alloy and the steel matrix, the resintering conditions directly affect the element diffusion depth and interface reaction degree between the copper alloy and the steel, on this basis, the annealing refines the grains, adjusts the stress distribution between the nickel-bismuth-copper alloy and the steel, adjusts the microstructure of the copper alloy, and improves the comprehensive performance of the entire bearing assembly. The inventors found that the strength of the bearing material is also improved under this condition.

[0033] The third aspect of the present application provides the application of the nickel bismuth copper alloy-steel bimetallic bearing material, which is suitable for manufacturing sliding bearings used in various types of generators, engines and the like.

[0034] The raw materials or reagents used in the present application are commercially available unless otherwise specified.

[0035] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0036] 1. The present application solves the problem of lead in sliding bearings. The bending strength of the nickel bismuth copper alloy-steel bimetallic bearing material of the present application is ≥200 MPa, the tensile strength is ≥360 MP, and at the same time, the linear expansion coefficient is low, the friction coefficient is low, and the comprehensive performance is superior, which can meet the market demand and has environmental protection significance.

[0037] 2. The present application introduces specific contents of nickel, tin and bismuth, titanium diboride and silicon carbide into the copper-based bearing material, which can improve the bending strength and tensile strength of the bimetallic bearing material. At the same time, the friction of the bimetallic bearing material is improved.

[0038] 3. The present application improves the friction resistance stability of the bimetallic bearing at different temperatures by adding titanium diboride and silicon carbide with different particle sizes. When the weight ratio of silicon carbide and titanium diboride is 1:1.8-2.2, the linear expansion coefficient of the bimetallic bearing can be improved.

[0039] 4. The present application improves the wear resistance of the bearing by using specific initial firing, re-firing and annealing conditions, and at the same time, the strength of the bearing material is also improved. The analysis is that the initial firing, re-firing and annealing play a synergistic role among each other, which affects the metallurgical bonding quality between the specific ratio of nickel bismuth copper alloy and steel material in the present application, and further affects the performance of the steel material. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] The carbon content of the carbon steel material used in the examples and comparative examples is less than or equal to 0.25%, which is from Shanghai Yexiao Industry Co., Ltd., 20# steel, and the chemical composition (mass fraction) of the steel according to the standard GB / T699-1999 is as follows: C 0.17%~0.23%, Si 0.17%~0.37%, MnO 0.35%~0.65%, P≤0.035%, S≤0.035%, Ni≤0.30%, Cr≤0.25%, Cu≤0.25%.

[0042] Example 1

[0043] The present embodiment provides a nickel-bismuth-copper alloy-steel bimetallic bearing material. The nickel-bismuth-copper alloy powder is sintered on the surface of a carbon steel material with a carbon content of less than or equal to 0.25% by a high-temperature sintering furnace under the protection of hydrogen and nitrogen, and the nickel-bismuth-copper alloy-steel bimetallic bearing material is prepared through multiple sintering and rolling. The chemical composition of the nickel-bismuth-copper alloy powder is as follows: nickel 2.1%, tin 1.7%, bismuth 1.9%, silicon carbide 0.5%, titanium diboride 1.0%, lead 0.06%, and the total amount of other impurities is 0.3%, and the balance is copper.

[0044] The particle size distribution of the nickel-bismuth-copper alloy powder is as follows: -140 mesh~+200 mesh content is 1%; -200 mesh~+325 mesh content is 40%; -325 mesh content is 59%, relative to the total weight of the nickel-bismuth-copper alloy powder 100%.

[0045] The titanium diboride is compounded by titanium diboride with a particle size of 1-3 μm, a particle size of 15-20 μm, and a particle size of 30-40 μm at a weight ratio of 1:0.4:1.6. Fuximan Technology (Beijing) Co., Ltd.

[0046] The silicon carbide is compounded by silicon carbide with a particle size of 2 μm, a particle size of 10 μm, and a particle size of 45 μm at a weight ratio of 0.6:1:1.1. Fuximan Technology (Beijing) Co., Ltd.

[0047] The preparation method of the nickel-bismuth-copper alloy-steel bimetallic bearing material includes the following steps:

[0048] (1) The nickel-bismuth-copper alloy powder is prepared by accurately weighing the chemical composition of the nickel-bismuth-copper alloy powder according to the weight percentage, mixing and melting, and then using a fully enclosed high-pressure water atomization method to form a powder, and sieving according to the particle size distribution requirements of the nickel-bismuth-copper alloy powder to obtain the nickel-bismuth-copper alloy powder;

[0049] (2) The carbon content of the carbon steel plate is less than or equal to 0.25%, the plate is cut into a specified width, and after being rolled and leveled, the surface of the plate is treated, and a layer of nickel-bismuth-copper alloy powder is uniformly coated on the surface of the carbon steel plate. The specific thickness of the steel plate as a raw material is 20 mm, the width is 1 m, and the length is 2 m. The specific thickness of the plate after being rolled and leveled is 17 mm, the width is 1.17 m, and the length is 2 m, and the unevenness is not greater than 2 mm / m. The thickness of the plate after surface treatment is 17 mm, the width is 1.17 m, and the length is 2 m. The surface treatment refers to conventional oil removal treatment.

[0050] (3) Primary sintering: sintering is carried out under a hydrogen and nitrogen protective atmosphere, the heating rate is 65°C / h, the sintering temperature is 950°C, and the holding time is 60 minutes;

[0051] (4) Primary rolling: the material after the primary sintering in step (3) is rolled at room temperature to a specified thickness in a rolling mill, the thickness is the thickness of the steel plate-alloy layer, the thickness is 15 mm, and the rolling thickness accuracy is controlled within ±0.01 mm. The density of the alloy layer after rolling is 8.86 g / cm 3 ;

[0052] (5) Re-sintering: sintering is carried out again under a hydrogen and nitrogen protective atmosphere, the heating rate is 75°C / h, the sintering temperature is 930°C, and the holding time is 60 minutes, to obtain a re-sintered steel plate;

[0053] (6) Annealing treatment: the re-sintered steel plate is subjected to annealing treatment under a hydrogen and nitrogen protective atmosphere, the annealing temperature is 470°C, and the annealing time is 55 minutes;

[0054] (7) Precision rolling and leveling: the material after the annealing treatment is cooled and then rolled again at room temperature to a specified thickness, the total thickness of the steel plate-alloy layer is 12 mm, the thickness of the steel plate is 11.4 mm, the thickness of the layer composed of alloy powder is 0.6 mm, the rolling accuracy is controlled within ±0.01 mm, and the density of the alloy layer after rolling is 8.91 g / cm 3 .

[0055] The thickness of the steel plate in step (2) ranges from 20 mm, and the thickness of the nickel-bismuth-copper alloy powder ranges from 1 mm.

[0056] The primary sintering and the re-sintering are both carried out in a sintering furnace.

[0057] The sintering furnace is a mesh belt type continuous sintering furnace.

[0058] Example 2

[0059] The embodiment provides a nickel-bismuth-copper alloy-steel bimetal bearing material, nickel-bismuth-copper alloy powder is sintered on the surface of carbon content ≤0.25% carbon steel material under the protection of hydrogen and nitrogen through a high-temperature sintering furnace, and the nickel-bismuth-copper alloy-steel bimetal bearing material is prepared through multiple sintering and rolling; wherein the chemical composition of the nickel-bismuth-copper alloy powder is as follows in terms of percentage by weight: 1.8% of nickel, 1.6% of tin, 2.4% of bismuth, 0.7% of silicon carbide, 0.8% of titanium diboride, 0.08% of lead, and 0.2% of total amount of other impurities, and the balance is copper.

[0060] The particle diameter distribution of the nickel-bismuth-copper alloy powder is as follows in terms of percentage by weight: the content of -140 mesh to +200 mesh is 2%; the content of -200 mesh to +325 mesh is 35%; and the content of -325 mesh is 63%, relative to the total weight of 100% of the nickel-bismuth-copper alloy powder.

[0061] The titanium diboride is compounded by titanium diboride with a particle size of 1-3 μm, a particle size of 15-20 μm and a particle size of 30-40 μm at a weight ratio of 1:0.4:1.6. Fuximan Technology (Beijing) Co., Ltd.

[0062] The silicon carbide is compounded by silicon carbide with a particle size of 2 μm, a particle size of 10 μm and a particle size of 45 μm at a weight ratio of 0.6:1:1.1. Fuximan Technology (Beijing) Co., Ltd.

[0063] The preparation method of the nickel-bismuth-copper alloy-steel bimetal bearing material comprises the following steps:

[0064] (1) accurately weighing according to the percentage by weight of the chemical composition of the nickel-bismuth-copper alloy powder, mixing and melting, then adopting a fully-closed high-pressure water atomization method to prepare powder, and sieving according to the particle diameter distribution requirement of the nickel-bismuth-copper alloy powder, to obtain the nickel-bismuth-copper alloy powder;

[0065] (2) cutting the carbon content ≤0.25% carbon steel plate into a specified width, treating the surface after leveling through rolling, and uniformly coating a layer of nickel-bismuth-copper alloy powder on the surface of the carbon steel plate; the specific thickness, width and length of the steel plate as a raw material are 20 mm, 1 m and 2 m respectively; the specific thickness, width and length of the steel plate after leveling through rolling are 17 mm, 1.17 m and 2 m respectively, and the unevenness is not greater than 2 mm / m; the thickness, width and length of the steel plate after surface treatment are 17 mm, 1.17 m and 2 m respectively, and the surface treatment refers to conventional oil removal treatment;

[0066] (3) primary sintering: sintering under the protection of hydrogen and nitrogen atmosphere, the heating speed is 65 ℃ / h, the sintering temperature is 950 ℃, and the holding time is 60 minutes;

[0067] (4) Rough rolling: the material after the first sintering in step (3) is rolled in a rolling mill at room temperature to a specified thickness, the thickness of the steel plate-alloy layer is 15 mm, the rolling thickness accuracy is controlled within ±0.01 mm; the density of the alloy layer after rolling is 8.86 g / cm 3 ;

[0068] (5) Re-sintering: the sintering is performed again under the protection of hydrogen and nitrogen atmosphere, the heating rate is 75 ℃ / h, the sintering temperature is 950 ℃, and the holding time is 60 minutes, to obtain the re-sintered steel plate;

[0069] (6) Annealing treatment: the re-sintered steel plate is subjected to annealing treatment under the protection of hydrogen and nitrogen atmosphere, the annealing temperature is 500 ℃, and the annealing time is 60 min;

[0070] (7) Finish rolling and flattening: the material after the annealing treatment is cooled and then rolled again at room temperature to a specified thickness, the total thickness of the steel plate-alloy layer is 12 mm, the thickness of the steel plate is 11.4 mm, the thickness of the layer composed of alloy powder is 0.6 mm, the rolling accuracy is controlled within ±0.01 mm, and the density of the alloy layer after rolling is 8.91 g / cm 3 .

[0071] The thickness of the steel plate in step (2) ranges from 20 mm, and the thickness of the nickel-bismuth-copper alloy powder ranges from 1 mm.

[0072] Both the first sintering and the re-sintering are performed in a sintering furnace.

[0073] The sintering furnace is a mesh belt type continuous sintering furnace.

[0074] Example 3

[0075] The present embodiment provides a nickel-bismuth-copper alloy-steel dual metal bearing material, a nickel-bismuth-copper alloy powder is sintered on the surface of a carbon steel material with a carbon content of ≤0.25% by a high-temperature sintering furnace under the protection of hydrogen and nitrogen, and the nickel-bismuth-copper alloy-steel dual metal bearing material is prepared through multiple sintering and rolling; wherein the chemical composition of the nickel-bismuth-copper alloy powder is as follows in terms of weight percentage: nickel 1.5%, tin 2.5%, bismuth 1%, silicon carbide 1%, titanium diboride 1.5%, lead 0.04%, total amount of other impurities 0.3%, and the balance is copper.

[0076] Relative to the total weight of 100% of the nickel-bismuth-copper alloy powder, the particle size distribution of the nickel-bismuth-copper alloy powder is as follows in terms of weight percentage: -140 mesh to +200 mesh content is 5%; -200 mesh to +325 mesh content is 45%; -325 mesh content is 50%.

[0077] The titanium diboride is compounded by titanium diboride with particle size of 1-3 μm, titanium diboride with particle size of 15-20 μm and titanium diboride with particle size of 30-40 μm in a weight ratio of 1:0.4:1.6. Fuximan Technology (Beijing) Co., Ltd.

[0078] The silicon carbide is compounded by silicon carbide with particle size of 2 μm, silicon carbide with particle size of 10 μm and silicon carbide with particle size of 45 μm in a weight ratio of 0.6:1:1.1. Fuximan Technology (Beijing) Co., Ltd.

[0079] The preparation method of the nickel-bismuth-copper alloy-steel bimetal bearing material comprises the following steps:

[0080] (1) The nickel-bismuth-copper alloy powder is prepared by accurately weighing the chemical components of the nickel-bismuth-copper alloy powder according to the weight percentage, mixing and melting, and then using a fully-closed high-pressure water atomization method to form a powder, and sieving according to the particle diameter distribution requirements of the nickel-bismuth-copper alloy powder to obtain the nickel-bismuth-copper alloy powder;

[0081] (2) The carbon content of the carbon steel plate is ≤0.25%, the carbon steel plate is cut into a specified width, the surface is treated after being flattened by rolling, and a layer of nickel-bismuth-copper alloy powder is uniformly coated on the surface of the carbon steel plate;

[0082] (3) Primary sintering: sintering is performed under a hydrogen and nitrogen protective atmosphere, the heating rate is 65 ℃ / h, the sintering temperature is 950 ℃, and the holding time is 60 minutes;

[0083] (4) Primary rolling: the material after the primary sintering in step (3) is rolled to a specified thickness at room temperature in a rolling mill, and the rolling thickness precision is controlled within ±0.01 mm; the density of the alloy layer after rolling is 8.86 g / cm 3 ;

[0084] (5) Re-sintering: sintering is performed again under a hydrogen and nitrogen protective atmosphere, the heating rate is 75 ℃ / h, the sintering temperature is 900 ℃, and the holding time is 60 minutes, to obtain the re-sintered steel plate;

[0085] (6) Annealing treatment: the re-sintered steel plate is subjected to annealing treatment under a hydrogen and nitrogen protective atmosphere, the annealing temperature is 450 ℃, and the annealing time is 50 minutes;

[0086] (7) Precision rolling and flattening: the material after the annealing treatment is cooled and then rolled again at room temperature to a specified thickness, the rolling precision is controlled within ±0.01 mm, and the density of the alloy layer after rolling is 8.91 g / cm 3 .

[0087] The thickness of the steel plate in step (2) ranges from 20 mm, and the thickness of the nickel-bismuth-copper alloy powder ranges from 1 mm.

[0088] The primary sintering and the re-sintering are both performed in a sintering furnace.

[0089] The sintering furnace is a mesh belt type continuous sintering furnace.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 1 is that the chemical composition of the nickel bismuth copper alloy powder is, by weight percentage, nickel 1.1%, tin 2.9%, bismuth 1.7%, silicon carbide 1.3%, titanium diboride 0.3%, lead 0.06%, and the total amount of other impurities is 0.3%, with the balance being copper.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 1 is that the particle size distribution of the nickel bismuth copper alloy powder is, by weight percentage, -140 mesh to +200 mesh content of 66%; -200 mesh to +325 mesh content of 4%; and -325 mesh content of 30%, relative to the total weight of 100% of the nickel bismuth copper alloy powder.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 1 is that the titanium diboride is compounded in a weight ratio of 1:1:1 of particle size 1-3 μm, particle size 15-20 μm, and particle size 30-40 μm.

[0096] Comparative Example 4

[0097] The difference between this comparative example and Example 1 is that the silicon carbide is compounded in a weight ratio of 1:1:1 of particle size 2 μm, particle size 10 μm, and particle size 45 μm.

[0098] Comparative Example 5

[0099] The difference between this comparative example and Example 1 is that the initial firing, re-firing, and annealing conditions are different.

[0100] Initial firing: sintering is performed under a hydrogen and nitrogen protective atmosphere, the heating rate is 90°C / h, the sintering temperature is 1100°C, and the holding time is 30 minutes.

[0101] Re-firing: sintering is performed again under a hydrogen and nitrogen protective atmosphere, the heating rate is 90°C / h, the sintering temperature is 800°C, the holding time is 30 minutes, and a re-fired steel plate is obtained.

[0102] Annealing treatment: the re-fired steel plate is subjected to annealing treatment under a hydrogen and nitrogen protective atmosphere, the annealing temperature is 400°C, and the annealing time is 40 minutes.

[0103] Performance testing

[0104] The nickel bismuth copper alloy-steel bimetallic bearing materials of examples 1-3 and comparative examples 1-5 were subjected to performance tests.

[0105] 1. The friction and wear test was carried out on a MMU-10 type (high temperature) end face friction and wear tester (Shandong Dacheng Tester Co., Ltd.) under oil-free lubrication, the rotating speed was set to 735 r / min, the experimental load was 120 kg, and the upper sample material was 40Cr with a hardness of 52 HRC. The dry friction coefficients at 25 DEG C and 200 DEG C were measured, and the wear scar depth at 25 DEG C was measured.

[0106] 2. The linear expansion coefficient was calculated according to the formula a = delta d / [d0 * (t1-t0)], wherein delta d is the diameter expansion amount of the bearing = d1-d0, unit: mm, a is the linear expansion coefficient of the bearing steel, d0 is the initial diameter of the bearing, d1 is the diameter of the bearing when heated to 400 DEG C, t1 is the temperature of the bearing after heating (400 DEG C), and t0 is the initial temperature of the bearing (20 DEG C).

[0107] 3. The tensile strength and yield strength of the bearing material were measured according to GB / T228-2002. The bearing material had a hollow cylindrical shape, a length of 10 cm, an outer diameter of 80 mm, a thickness of 12 mm, and a circular cross-sectional shape; and the test condition was 25 DEG C.

[0108] Table 1 Performance test results

[0109] It can be seen from the results that the yield strength and tensile strength of the nickel bismuth copper alloy-steel bimetallic bearing material prepared in examples 1-3 are greatly improved compared with the existing copper-lead alloy sliding bearing bimetallic material, the linear expansion coefficient is small, the wear resistance is good, and the friction changes little under normal temperature and high temperature conditions, which can meet the demand of nickel bismuth copper alloy-steel bimetallic bearing in high temperature application. It can be seen from the results that the nickel bismuth copper alloy-steel bimetallic bearing material prepared in example 1 has the best comprehensive performance under the specific chemical composition of the nickel bismuth copper alloy powder raw material ratio and the proportion of silicon carbide and titanium diboride, the yield strength is greater than 245 MPa, the tensile strength is greater than 390 MPa, and the linear expansion coefficient is less than 1.10*10 -5 / ℃, which can fully meet the market demand and has a wide application prospect.

[0110] The above describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A nickel bismuth copper alloy-steel bimetallic bearing material characterized by, The preparation method of the nickel-bismuth-copper alloy-steel bimetal bearing material comprises the following steps: (1) accurately weigh the nickel-bismuth-copper alloy powder according to the weight percentage of the chemical composition of the nickel-bismuth-copper alloy powder, mix and melt, and then use a fully enclosed high-pressure water atomization method to prepare the powder, sieve according to the particle size distribution requirements of the nickel-bismuth-copper alloy powder, and obtain the nickel-bismuth-copper alloy powder; wherein the chemical composition of the nickel-bismuth-copper alloy powder is 1.5-3.0% nickel, 1-2.5% tin, 1-3% bismuth, 0.2-1% silicon carbide, 0.5-1.5% titanium diboride, ≤0.1% lead, and ≤1.5% total amount of other impurities, with the balance being copper, all by weight percentage; the particle size distribution of the nickel-bismuth-copper alloy powder is 0.2-5% -140 mesh to +200 mesh, 30-45% -200 mesh to +325 mesh, and 50-85% -325 mesh, all by weight percentage, relative to the total weight of the nickel-bismuth-copper alloy powder 100% by weight; the weight ratio of the silicon carbide and the titanium diboride is 1:1-2.5; the titanium diboride is a compound of titanium diboride with a particle size of 1-3 μm, a particle size of 15-20 μm, and a particle size of 30-40 μm, with a weight ratio of 1:0.3-0.7:1.4-1.8; the silicon carbide is a compound of silicon carbide with a particle size of 2 μm, a particle size of 10 μm, and a particle size of 45 μm, with a weight ratio of 0.4-0.8:1:0.8-1.2; (2) cut the carbon content ≤0.25% carbon steel plate into a specified width, level it by rolling, and then uniformly coat a layer of nickel-bismuth-copper alloy powder on the surface of the carbon steel plate after surface treatment; (3) preliminary firing: sintering under a hydrogen and nitrogen protective atmosphere, with a heating rate of 60-70℃ / h, a sintering temperature of 900-1000℃, and a holding time of 15-200 minutes; (4) Rough rolling: the material after the first sintering in step (3) is rolled to a specified thickness at room temperature in a rolling mill, and the rolling thickness accuracy is controlled within ±0.01 mm; the density of the alloy layer after rolling is 8.8-8.95 g / cm 3 ; (5) re-firing: again sintering under a hydrogen and nitrogen protective atmosphere, with a heating rate of 70-80℃ / h, a sintering temperature of 900-950℃, and a holding time of 15-200 minutes, to obtain the re-fired steel plate; (6) annealing treatment: annealing the re-fired steel plate under a hydrogen and nitrogen protective atmosphere, at an annealing temperature of 450-500℃ and an annealing time of 50-60 minutes; the chemical composition of the nickel-bismuth-copper alloy powder is 1.6-2.4% nickel, 1.5-2.0% tin, 1.5-2.5% bismuth, 0.4-0.7% silicon carbide, 0.8-1.2% titanium diboride, ≤0.1% lead, and ≤0.5% total amount of other impurities, with the balance being copper, all by weight percentage. (7) Finish leveling: after the annealing treatment, the material is cooled and then rolled again at room temperature to the specified thickness, with the rolling precision controlled within ±0.01 mm, and the alloy layer density after rolling is 8.9-8.95 g / cm 3 .

2. The nickel-bismuth-copper alloy-steel bimetallic bearing material of claim 1, wherein, the particle size distribution of the nickel-bismuth-copper alloy powder is 0.2-2% -140 mesh to +200 mesh, 35-45% -200 mesh to +325 mesh, and 50-75% -325 mesh, all by weight percentage, relative to the total weight of the nickel-bismuth-copper alloy powder 100% by weight.

3. The nickel-bismuth-copper alloy-steel bimetallic bearing material of claim 1, wherein, The thickness of the steel plate used as the raw material in step (2) is in the range of 0.5mm-50.0mm, and the thickness of the nickel-bismuth-copper alloy powder is in the range of 0.25mm-3.0mm.

4. The nickel-bismuth-copper alloy-steel bimetallic bearing material of claim 1, wherein, ​ 5. Use of the nickel bismuth copper alloy-steel bimetallic bearing material of any one of claims 1-4 in the manufacture of sliding bearings for use in generators and engines.