Preparation method of tin-based babbitt metal brazing coating and preparation method of tin-based babbitt metal bearing bush

Abstract

The invention provides a preparation method of a tin-based babbitt metal brazing coating and a preparation method of a tin-based babbitt metal bearing bush. The preparation method of the brazing coating comprises the steps that a bearing bush base plate is pretreated; alloy powder paste fluid is prepared; coating the alloy powder paste fluid on the surface of a substrate, and drying to form an alloy powder coating; cMT additive welding is conducted, a welding wire is melted at high temperature and subjected to an in-situ reaction with the alloy powder coating on the surface of the base plate, and a tin-based babbitt metal brazing coating is synthesized in situ; the preparation method of the bearing bush comprises the steps that the tin-based babbitt metal brazing coating is synthesized in situ, and the bearing bush is machined to the target size. According to the preparation method of the tin-based babbitt alloy brazing coating and the preparation method of the bearing bush, the technology of volatilizable paste alloy powder and CMT secondary metallurgy is adopted, the tin-based babbitt alloy brazing coating is synthesized in situ, the brazing coating has the excellent organization structure and performance, crystal grains of the brazing coating are fine and evenly distributed, and the hardness of the brazing coating is greatly improved. The strength, the wear resistance and the fatigue resistance of the bearing bush can be obviously improved.

Description

Technical Field

[0001] This invention relates to the field of bearing manufacturing technology, and more specifically, to a method for preparing a tin-based Babbitt alloy brazing coating and a method for preparing tin-based Babbitt alloy bearings. Background Technology

[0002] Tin-based Babbitt metal is a low-melting-point, wear-resistant bearing alloy with a tin base and added alloying elements such as antimony and copper. Due to its excellent anti-friction, wear resistance, and fatigue resistance, it is widely used in the manufacture of bearing bushes for various mechanical equipment. Bearing bushes are important support components in mechanical equipment; their main function is to reduce friction between the shaft and the bearing, withstand radial and axial forces, and ensure the smooth operation of the equipment. The performance of bearing bushes directly affects the operating efficiency, reliability, and service life of the equipment. Therefore, the development of high-performance bearing bush materials and their manufacturing processes has always been a research hotspot in the fields of materials science and mechanical engineering.

[0003] In modern industry, with the continuous increase in the operating speed and load of mechanical equipment, higher demands are placed on the performance of bearing bushes. While traditional Babbitt alloy bearing bushes can meet the needs of general industrial equipment, their performance is still insufficient in some high-precision, high-load, and high-speed equipment. For example, in high-end equipment such as aerospace, automotive, shipbuilding, and large generators, bearing bushes need to possess higher strength, better wear resistance, and fatigue resistance to ensure the long-term stable operation of the equipment. Furthermore, with increasing environmental protection and energy-saving requirements, the lightweighting and efficiency improvement of mechanical equipment have become development trends, which also pose new challenges to the performance of bearing bush materials.

[0004] Currently, the main manufacturing processes for Babbitt alloy bearings include gravity casting, centrifugal casting, and electric arc additive manufacturing. However, these traditional processes all have certain limitations in practical applications and cannot meet the requirements of modern industry for high performance and high reliability of bearings.

[0005] Gravity casting involves pouring molten metal into a mold under the influence of gravity. Its main drawback is low interfacial bonding strength. Because the molten metal flows slowly and cools relatively slowly during gravity casting, the bond between the metal and the substrate is not tight enough, easily leading to micropores or cracks at the interface, thus affecting the overall strength and service life of the bearing.

[0006] Centrifugal casting uses centrifugal force to propel molten metal against the inner wall of a mold for shaping. While centrifugal casting improves process strength to some extent, it still suffers from issues such as microstructure segregation and coarse microstructure. During centrifugal casting, under the influence of centrifugal force, denser alloying elements segregate towards the inner wall of the mold, resulting in an uneven microstructure. Simultaneously, due to the relatively slow cooling rate, metal grains tend to grow, forming a coarse microstructure. This not only reduces the strength of the bearing but also affects its wear resistance and fatigue resistance.

[0007] Arc additive manufacturing is a process that uses an electric arc to melt and deposit metal wire layer by layer. While this process offers improvements in microstructure and strength, it presents significant challenges in processing high-strength tin-based Babbitt alloy wire. Tin-based Babbitt alloys are highly brittle and prone to cracking during processing, making the production of high-quality tin-based Babbitt alloy wires extremely difficult. This limits the application of arc additive manufacturing in the fabrication of tin-based Babbitt alloy bearings.

[0008] In view of this, the present invention is hereby proposed. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing a tin-based Babbitt alloy brazing coating and a tin-based Babbitt alloy bearing. The method employs a "volatile paste alloy powder + CMT secondary metallurgy" process, where the welding wire melts at high temperature and reacts in situ with the alloy powder coating on the substrate surface to form a secondary metallurgical bond, thus synthesizing a tin-based Babbitt alloy brazing coating in situ. This brazing coating exhibits excellent microstructure and properties, with fine and uniformly distributed grains, significantly improving the strength, wear resistance, and fatigue resistance of the bearing.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A method for preparing a tin-based Babbitt alloy brazing coating includes the following steps: Step S1: Pre-treatment of bearing substrate; Step S2: Prepare the gold powder paste fluid; Step S3: Coat the substrate surface with alloy powder paste fluid and dry to form an alloy powder coating; Step S4, CMT additive welding: The welding wire melts at high temperature and reacts in situ with the alloy powder coating on the substrate surface to synthesize a tin-based Babbitt alloy brazing coating in situ.

[0011] Furthermore, the pretreatment of the bearing substrate in step S1 includes degreasing, heating and dehydrogenation, and oxide layer removal.

[0012] Furthermore, the degreasing treatment method in step S1 is to clean the substrate surface with acetone or alcohol.

[0013] Furthermore, the heating dehydrogenation treatment method in step S1 is as follows: heat the substrate to 200℃~300℃ and maintain it for 1~4 hours.

[0014] Furthermore, the oxide layer removal method in step S1 is as follows: use an angle grinder to remove the oxide layer on the substrate surface to expose the fresh metal surface layer.

[0015] Furthermore, the drying temperature in step S3 is 100℃~150℃.

[0016] Furthermore, in step S3, the coating thickness of the alloy powder paste fluid on the substrate surface is 0.05 mm to 3 mm.

[0017] Further, the alloy powder paste fluid in step S2 comprises: 55~75wt% reinforced alloy powder, 0.01~3wt% binder, 15~20wt% volatile solvent, 0.1~0.5wt% leveling agent, and the balance being a co-solvent.

[0018] Furthermore, the reinforcing alloy powder is tin-based Babbitt alloy powder and / or metal powder containing trace elements.

[0019] Furthermore, the tin-based Babbitt alloy powder is at least one of SnCu alloy powder, SnSb alloy powder, and SnSbCu alloy powder.

[0020] Further, the trace element is at least one of Ni, Co, Cr, Si, Mn, Fe, and B; preferably, the amounts of trace elements added in the reinforced alloy powder are as follows: Ni 0~0.5, Co 0~0.5, Cr 0~0.8, Si 0~0.028, Mn 0~0.045, Fe 0~0.03, and B 0~0.003.

[0021] Furthermore, the metal powder containing trace elements is at least one of tin alloy powder containing trace elements, copper alloy powder containing trace elements, elemental tin powder containing trace elements, and elemental copper powder containing trace elements.

[0022] Furthermore, the adhesive is at least one of water glass and polyvinyl alcohol.

[0023] Furthermore, the volatile solvent is at least one of anhydrous ethanol and n-butanol.

[0024] Furthermore, the leveling agent is at least one of 0.5 wt% silicone oil and polyether-modified silicone oil.

[0025] Furthermore, the co-solvent is deionized water.

[0026] Furthermore, in step S4, the welding wire is at least one of SnSb4Cu4, SnSb8Cu4, SnSb8Cu8, and SnSb11Cu6.

[0027] Furthermore, in step S4, the welding current is 80~145A, including but not limited to 80A, 85A, 90A, 95A, 100A, 105A, 110A, 115A, 120A, 125A, 130A, 135A, 140A, and 145A, the wire feed speed is 6~12m / min, the welding speed is 6~12m / min, and the weld spacing is 6~12mm.

[0028] Furthermore, in step S4, the welding is divided into two layers. The first layer uses pulse mode for root pass welding, and the second layer uses CMT mode.

[0029] A method for preparing a tin-based Babbitt alloy bearing includes the following steps: Step A: Using the above-mentioned method for preparing tin-based Babbitt alloy brazing coating, a tin-based Babbitt alloy brazing coating is synthesized in situ on the bearing substrate. Step B: Machin the bearing bush to the target size.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method for preparing tin-based Babbitt alloy brazing coating and bearing bush of the present invention adopts the "volatile paste alloy powder + CMT secondary metallurgy" process. Through the high temperature generated during the welding process, the alloy powder coating and the welding wire undergo a "secondary metallurgy" in-situ reaction in the molten pool, and a high-performance tin-based Babbitt alloy brazing coating is synthesized in situ. The brazing coating has excellent microstructure and properties, with fine and uniform grains, which can significantly improve the strength, wear resistance and fatigue resistance of the bearing bush.

[0031] 2. The method for preparing the tin-based Babbitt alloy brazing coating and bearing bush of the present invention can improve the interfacial bonding strength: through the process of alloy powder brushing and CMT additive welding, the alloy powder and the substrate surface react fully at high temperature to form a strong metallurgical bond. The metallurgical bonding method overcomes the disadvantage of low interfacial bonding strength of gravity casting and significantly improves the overall strength and reliability of the bearing bush.

[0032] 3. The method for preparing the tin-based Babbitt alloy brazing coating and bearing of the present invention can improve the microstructure: the in-situ synthesized tin-based Babbitt alloy coating has a fine and uniform grain structure, avoiding the problems of microstructure segregation and coarse structure in centrifugal casting; the fine grain structure can improve the strength and toughness of the material, and also helps to improve wear resistance and fatigue resistance.

[0033] 4. The method for preparing tin-based Babbitt alloy brazing coating and bearing bush of the present invention can overcome processing limitations: by using alloy powder brushing and additive welding, there is no need for a complicated tin-based Babbitt alloy wire processing process, thereby overcoming the limitation of difficult processing of tin-based high-strength Babbitt alloy wire in arc additive manufacturing, reducing the difficulty of preparation, and improving production efficiency and yield.

[0034] 5. The method for preparing tin-based Babbitt alloy brazed coating and bearing bush of the present invention can improve the overall performance: by adding trace elements such as Ni, Co, Cr, Si, Mn, Fe, and B, the performance of the alloy is further optimized; the trace elements can refine the grains, increase hardness, and enhance wear resistance and fatigue resistance, so that the prepared bearing bush has been significantly improved in terms of high strength, high wear resistance and high fatigue resistance, which can better meet the requirements of modern industry for high-performance bearing bushes. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a process flow diagram of the method for preparing the tin-based Babbitt alloy brazing coating of the present invention; Figure 2 Electron micrograph of the tin-based Babbitt alloy brazing coating prepared in Example 1; Figures 3-4 Scanned image of the microstructure of the tin-based Babbitt alloy brazing coating prepared in Example 2; Figures 5-6 The image shows the microstructure of the tin-based Babbitt alloy brazing coating prepared in Example 3. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0038] The following examples are intended to illustrate, not limit, the invention. In these examples, unless otherwise specified, all parts and percentages are by weight.

[0039] A method for preparing a tin-based Babbitt alloy brazing coating includes the following steps: Step S1: Pretreatment of bearing substrate, including degreasing, heating to remove hydrogen, and removing oxide layer from the bearing substrate; Step S2: Prepare the gold powder paste fluid; Step S3: Coat the substrate surface with alloy powder paste fluid and dry to form an alloy powder coating; Step S4, CMT additive welding: The welding wire melts at high temperature and reacts in situ with the alloy powder coating on the substrate surface to form a secondary metallurgical bond, thus synthesizing a tin-based Babbitt alloy brazing coating in situ.

[0040] Preferably, the degreasing treatment method in step S1 is as follows: use acetone or alcohol to clean the substrate surface to remove oil and impurities and ensure that the substrate surface is clean.

[0041] Preferably, the heating dehydrogenation treatment method in step S1 is as follows: heating the substrate to 200℃~300℃, including but not limited to 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, and 300℃, and holding it for 1~4 hours, including but not limited to 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, and 4 hours, to remove hydrogen and other impurity gases inside the substrate, prevent the generation of pores and cracks during subsequent welding, and improve the surface quality and bonding strength of the substrate.

[0042] Preferably, the oxide layer removal method in step S1 is as follows: use an angle grinder to remove the oxide layer on the substrate surface to expose the fresh metal surface layer.

[0043] Preferably, the alloy powder paste fluid in step S2 includes 55-75 wt% reinforcing alloy powder, 0.01-3 wt% binder, 15-20 wt% volatile solvent, 0.1-0.5 wt% leveling agent, and the balance being a co-solvent. To facilitate coating, the alloy powder is mixed with solvents that are easily volatile upon heating, such as alcohol and water, to prepare a paste fluid. This paste fluid has good fluidity and adhesion and can be uniformly coated on the substrate surface.

[0044] Preferably, the reinforcing alloy powder is tin-based Babbitt alloy powder and / or metal powder containing trace elements; the trace elements play a role in grain refinement and dispersion strengthening.

[0045] Preferably, the tin-based Babbitt alloy powder is at least one of SnCu alloy powder, SnSb alloy powder, and SnSbCu alloy powder.

[0046] Preferably, the trace element is at least one of Ni, Co, Cr, Si, Mn, Fe, and B; the amounts of trace elements added in the reinforced alloy powder are as follows: Ni 0~0.5, Co 0~0.5, Cr 0~0.8, Si 0~0.028, Mn 0~0.045, Fe 0~0.03, and B 0~0.003.

[0047] Preferably, the metal powder containing trace elements is at least one of tin alloy powder containing trace elements, copper alloy powder containing trace elements, elemental tin powder containing trace elements, and elemental copper powder containing trace elements.

[0048] Preferably, the adhesive is at least one of water glass and polyvinyl alcohol.

[0049] Preferably, the volatile solvent is at least one of anhydrous ethanol and n-butanol; the volatile solvent is the main solvent and can evaporate rapidly.

[0050] Preferably, the leveling agent is at least one of 0.5 wt% silicone oil and polyether-modified silicone oil; the leveling agent prevents cracking after drying.

[0051] Preferably, the co-solvent is deionized water; the co-solvent is used to adjust the viscosity.

[0052] The alloy powder paste fluid prepared in step S2 of this invention is a volatile paste fluid with no residue, so as to achieve one-time, uniform and firm pre-placement of reinforcing alloy powder on the surface of the bearing substrate; then it is completely evaporated in a hot air duct at 100~150℃ within 3~5 minutes, leaving no organic residue, ensuring that the subsequent CMT welding wire and reinforcing powder undergo a "secondary metallurgical" in-situ reaction to generate a high wear-resistant brazing coating, thereby improving the performance and quality of the bearing; the brazing coating is a special coating formed on the surface of the substrate through a brazing process, which essentially utilizes the wetting and spreading ability of liquid brazing filler metal on the substrate to form a surface strengthening layer with specific functions (such as wear resistance and corrosion resistance) through metallurgical bonding.

[0053] The alloy powder paste fluid prepared in step S2 of this invention can achieve the following: (1) a 0.4~0.6 mm thick film can be brushed at room temperature without dripping, and the wet film thickness is uniform. After drying, there are no cracks, no peeling, and no powder loss during handling; (2) trace elements and main alloy powder are fully wetted in the paste, and the grains are significantly refined; (3) 100% of the volatiles are dispersed, which does not reduce the activity of the molten pool, enhances the full in-situ reaction between the high-performance alloy powder and the welding wire, generates a hard phase, and improves the hardness of the coating; (4) the solvent evaporates quickly and carries away the heat, avoiding secondary heating of the substrate and causing the substrate to absorb hydrogen again after dehydrogenation treatment; (5) the formula is environmentally friendly.

[0054] Preferably, the drying temperature in step S3 is 100℃~150℃, including but not limited to 100℃, 110℃, 120℃, 130℃, 140℃, and 150℃; the prepared alloy powder paste fluid is uniformly coated on the surface of the pretreated substrate, and then the substrate is placed in a drying device and dried at a certain temperature to allow the solvent to evaporate completely, leaving a uniform alloy powder coating.

[0055] Preferably, the coating thickness of the alloy powder paste fluid on the substrate surface in step S3 is 0.05mm to 3mm, including but not limited to 0.05mm, 0.1mm, 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, and 3mm.

[0056] Preferably, the welding wire in step S4 is at least one of SnSb4Cu4, SnSb8Cu4, SnSb8Cu8, and SnSb11Cu6; the welding wire used in this invention is a conventional grade of tin-based Babbitt alloy wire, which is easy to process. The higher the antimony-copper content in the welding wire, the better the wire performance, but the more difficult the processing will be.

[0057] Preferably, in step S4, the welding current is 80~145A, including but not limited to 80A, 85A, 90A, 95A, 100A, 105A, 110A, 115A, 120A, 125A, 130A, 135A, 140A, and 145A; the wire feeding speed is 6~12m / min, including but not limited to 6m / min, 7m / min, 8m / min, 9m / min, 10m / min, 11m / min, and 12m / min; the welding speed is 6~12m / min, including but not limited to 6m / min, 7m / min, 8m / min, 9m / min, 10m / min, 11m / min, and 12m / min; and the weld spacing is 6~12mm, including but not limited to 6mm, 8mm, 10mm, and 12mm. Preferably, the welding in step S4 is divided into two layers: the first layer is a pulse mode for root pass welding, and the second layer is a CMT mode. Welding is performed using a CMT (Cold Metal Transfer) additive welding machine. The CMT additive welding machine has the advantages of precise control of welding parameters and droplet transfer, which can ensure the stability and quality of the welding process. During the welding process, the welding wire melts at high temperature and reacts in situ with the alloy powder coating on the substrate surface, forming a secondary metallurgical process.

[0058] A method for preparing a tin-based Babbitt alloy bearing includes the following steps: Step A: Using the above-mentioned method for preparing tin-based Babbitt alloy brazing coating, a tin-based Babbitt alloy brazing coating is synthesized in situ on the bearing substrate. Step B: After welding, the bearing bush is machined to the target size.

[0059] Example 1 A method for preparing a tin-based Babbitt alloy bearing includes the following steps: a. Use acetone to degrease the bearing substrate; after the treatment, put the substrate into a heat preservation furnace and heat it to 280°C for 4 hours to perform dehydrogenation treatment on the substrate; after the treatment, use an angle grinder to remove the oxide layer on the surface of the substrate to expose the fresh metal surface. b. Mix 65wt% (60wt% 300 mesh Sn20Sb60Cu20 + 5wt% Cu4B), 3wt% polyvinyl alcohol, 18wt% anhydrous ethanol, 0.5wt% silicone oil, and the balance deionized water according to the mass fraction, put them into a mixer and stir for 15 minutes to prepare an alloy powder paste fluid. c. Apply a second layer to the substrate surface using a brush, and after drying, apply a second layer by brushing. Then place the substrate in a drying oven at 150°C for 45 minutes to dry. d. Set welding parameters and use a CMT additive welding machine for welding. The welding material is 1.6mm SnSb8Cu4 alloy wire. The first layer is welded using pulse mode for the root pass, and the second layer is welded using CMT mode: the first layer is welded using pulse mode with a welding current of 120A, a wire feed speed of 12m / min, a welding speed of 11m / min, and a weld spacing of 10mm; the second layer is welded using CMT mode with a welding current of 90A, a wire feed speed of 10m / min, a welding speed of 9m / min, and a weld spacing of 10mm. e. After welding, perform machining and grinding.

[0060] Example 2 A method for preparing a tin-based Babbitt alloy bearing includes the following steps: a. Use acetone to degrease the bearing substrate; after the treatment, put the substrate into a heat preservation furnace and heat it to 290°C for 3 hours to perform dehydrogenation treatment on the substrate; after the treatment, use an angle grinder to remove the oxide layer on the surface of the substrate to expose the fresh metal surface. b. Mix 58wt% reinforced alloy powder (58wt% 300 mesh SnCo alloy powder), 1.9wt% polyvinyl alcohol, 16wt% anhydrous ethanol, 0.5wt% silicone oil, and the balance deionized water by mass fraction, and stir in a mixer for 20 minutes. c. Apply a second layer to the substrate surface using a brush, dry it, and then place it in a drying oven at 150°C for 60 minutes. d. Set welding parameters and use a CMT additive welding machine for welding. The welding material is 1.6mm SnSb11Cu6 alloy wire. The first layer is welded using pulse mode for the root pass, and the second layer is welded using CMT mode: the first layer is welded using pulse mode with a welding current of 130A, a wire feed speed of 10m / min, a welding speed of 8m / min, and a weld spacing of 10mm; the second layer is welded using CMT mode with a welding current of 100A, a wire feed speed of 9m / min, a welding speed of 8m / min, and a weld spacing of 10mm. e. After welding, perform machining and grinding.

[0061] Example 3 A method for preparing a tin-based Babbitt alloy bearing includes the following steps: a. Use acetone to degrease the bearing substrate; after the treatment, put the substrate into a heat preservation furnace and heat it to 280℃ for 3.5 hours to perform dehydrogenation treatment on the substrate; after the treatment, use an angle grinder to remove the oxide layer on the surface of the substrate to expose the fresh metal surface. b. Mix 63wt% reinforced alloy powder (63wt% 300 mesh SnMn alloy powder), 2.4wt% polyvinyl alcohol, 17.5wt% anhydrous ethanol, 0.5wt% silicone oil, and the balance deionized water according to the mass fraction, and stir in a mixer for 20 minutes. c. Apply a second layer to the substrate surface using a brush, dry it, and then place it in a drying oven at 150°C for 60 minutes. d. Set welding parameters and use a CMT additive welding machine for welding. The welding material is 1.6mm SnSb11Cu6 alloy wire. The first layer is welded using pulse mode for the root pass, and the second layer is welded using CMT mode: the first layer is welded using pulse mode with a welding current of 135A, a wire feed speed of 8m / min, a welding speed of 8m / min, and a weld spacing of 10mm; the second layer is welded using CMT mode with a welding current of 85A, a wire feed speed of 10m / min, a welding speed of 8.5m / min, and a weld spacing of 10mm. e. After welding, perform machining and grinding.

[0062] Comparative Example 1 The comparative example is prepared using the conventional additive manufacturing method for bearing bushes: after the bearing bush substrate is polished, an arc additive manufacturing process is performed to obtain a surface alloy layer, and the welding wire is SnSb8Cu4.

[0063] Comparative Example 2 The comparative example is prepared using the conventional additive manufacturing method for bearing bushes: after the bearing bush substrate is polished, an arc additive manufacturing process is performed directly to obtain a surface alloy layer, and the welding wire is SnSb11Cu6.

[0064] Experimental example: I. The chemical composition of the brazing coating prepared in Example 1 and the alloy layer prepared in Comparative Example 1 is shown in Table 1.

[0065] Table 1 Chemical composition of the brazing coating in Example 1 and the alloy layer in Comparative Example 1 (unit: wt%)

[0066] As shown in Table 1, the content of antimony (Sb) and copper (Cu) in the brazing coating prepared by Example 1 and the alloy layer prepared by Comparative Example 1 (SnSb8Cu4) shows that the copper content in Example 1 increased from about 3.5 to about 5.3, and the antimony content increased from about 7.5 to about 8.0 compared to Comparative Example 1. This indicates that the "volatile paste alloy powder + CMT secondary metallurgy" process of the present invention can prepare alloy layers with high antimony and high copper content, and has the following advantages: (1) Antimony and tin form a hard phase SnSb2 (β phase), which increases the number and size of the hard phase and significantly improves the hardness, compressive strength and wear resistance of the alloy; (2) Copper and tin form a needle-like or star-shaped hard phase Cu6Sn5 (ε phase), which forms a denser skeleton network structure, effectively inhibiting the SnSb phase from floating due to density difference during solidification (i.e. reducing specific gravity segregation), making the structure more uniform, and further enhancing the strength and high temperature stability of the alloy.

[0067] This invention replaces traditional gravity / centrifugal casting and wire additive manufacturing with "volatile paste alloy powder + CMT secondary metallurgy" to prepare a high-antimony, high-copper-tin-based wear-resistant brazing coating on the bearing surface in one step. This effectively suppresses specific gravity segregation and β-SnSb agglomeration. The coating is dense and uniform with controllable thickness, enabling the controllable preparation and engineering application of high alloy content Babbitt alloy.

[0068] The increase in antimony content increases the volume fraction of the β-SnSb hard phase, and the increase in copper content multiplies the Cu6Sn5 dispersed particles. The synergy of the two will improve the Brinell hardness of the alloy layer, reduce the coefficient of friction, and significantly improve the service life of the bearing under high-speed and heavy-load conditions.

[0069] High antimony and high copper content result in a traditional casting-skinning-extrusion-drawing process with an elongation rate of less than 3%, and a single-shift 8-hour production capacity of φ1.6mm wire of less than 50 kg. This invention disperses high-performance doped alloy powder in micron-sized powder form within a volatile paste, bypassing the extrusion / drawing process, avoiding brittle breakage of the welding wire, improving the yield of conventional welding wire, and achieving low-cost, large-area, continuous production.

[0070] II. The Brinell hardness comparison of the brazing coating prepared in Example 1 and the alloy layer prepared in Comparative Example 1 is shown in Table 2.

[0071] Table 2. Comparison of Brinell hardness between the brazing coating prepared in Example 1 and the alloy layer prepared in Comparative Example 1.

[0072] As shown in Table 2, the average Brinell hardness of the brazed coating of Example 1 (high antimony and high copper) is 27.0 HBW, which is 14.81% higher than the average Brinell hardness of 23.56 HBW of the alloy layer of Comparative Example 1 (SnSb8Cu4), and the fluctuation is smaller. The lowest Brinell hardness of the brazed coating of Example 1 (26.6 HBW) is still higher than the highest Brinell hardness of 24.2 HBW of the alloy layer of Comparative Example 1. This directly proves that the high antimony and high copper composition combined with the "volatile paste alloy powder + CMT secondary metallurgy" process of this invention can significantly and stably improve the surface hardness of tin-based Babbitt alloy, meeting the requirements of high load and long service life of bearings.

[0073] III. Comparison of the interfacial bonding strength of the brazing coatings prepared in Examples 2 and 3 and the alloy layer prepared in Comparative Example 2.

[0074] Table 3. Comparison of interfacial bonding strength between the brazing coatings prepared in Examples 2-3 and the alloy layer prepared in Comparative Example 2.

[0075] Table 3 shows that the interfacial bonding strength of the brazed coatings prepared in Example 2 and Example 3 is significantly higher than that of the alloy layer prepared in Comparative Example 2 (SnSb11Cu6). The average interfacial bonding strength of Example 2 is 99.64 MPa, while that of Example 3 is 88.86 MPa, compared to only 79.46 MPa for Comparative Example 2. This significant improvement in interfacial bonding strength can be attributed to the special alloy composition and preparation process used in this invention. First, this invention optimizes the microstructure of the alloy by precisely controlling the alloy composition, such as a high proportion of antimony (Sb) and copper (Cu), and by adding trace elements such as manganese and cobalt. The addition of these elements helps to form a denser and more uniform alloy layer, thereby improving the interfacial bonding strength. High proportions of Sb and Cu promote the formation of more hard phases, such as (SnSb) and Cu6Sn5, which act as reinforcing agents in the alloy, improving the hardness and wear resistance of the alloy layer. Simultaneously, the addition of trace elements such as Mn refines the grain size, further enhancing the strength and toughness of the alloy layer. Secondly, the preparation processes employed in this invention, such as paste-like fluid coating and CMT additive welding, facilitate metallurgical bonding between the alloy layer and the substrate. This bonding method achieves interdiffusion and chemical reaction between the alloy layer and the substrate, forming a metallurgical bond that provides higher interfacial bonding strength, thereby improving the reliability and durability of the entire component. The addition of trace elements such as Mn refines the grain size, further enhancing the strength and toughness of the alloy layer. Simultaneously, the addition of trace elements also helps suppress the formation of the brittle FeSn phase at the interface. The added trace amounts of Mn / Co and other elements can form more stable compounds with Fe, thereby reducing the formation of the FeSn phase and improving the toughness of the interface. In summary, by optimizing the alloy composition and preparation process, this invention has achieved a significant improvement in the interfacial bonding strength between the tin-based Babbitt alloy layer and the substrate.

[0076] IV. Electron micrograph of the tin-based Babbitt alloy brazing coating prepared in Example 1, as shown in the figure. Figure 2 As shown.

[0077] Electron microscopy images show that the tin-based Babbitt alloy has a fine and uniform microstructure. The soft matrix tin-based α solid solution has fine grains, which gives the alloy good embedding and compliance properties. It can deform slightly to accommodate minor misalignment of the shaft and reduce friction and wear with the journal. The hard particles SnSb phase and Cu6Sn5 phase are uniformly distributed in the soft matrix and mainly bear the load during bearing operation. This is the microstructural feature that enables it to be used as an excellent sliding bearing material.

[0078] V. Scanned images of the microstructure of the tin-based Babbitt alloy brazing coating prepared in Example 2, as shown. Figure 3 As shown.

[0079] (1) The surface scan image shows the distribution of Co (orange) in the alloy layer. It can be seen that Co is uniformly distributed throughout the alloy layer without obvious aggregation or segregation. This indicates that the preparation process of the present invention successfully introduces Co into the tin-based Babbitt alloy, realizing the preparation of an alloy layer containing Co. The uniform distribution of Co helps to improve the mechanical properties of the alloy layer, such as hardness, strength, and wear resistance. (2) The surface scan image shows that in addition to Co, Cu (green) and Sb (yellow) are also uniformly distributed in the alloy layer. This uniform element distribution indicates that the preparation process of the present invention can prepare an alloy layer with uniform composition, avoiding the element segregation problem that may occur in traditional methods. The uniform element distribution helps to improve the overall performance of the alloy layer, making it exhibit better stability and reliability in practical applications. (3) The surface scan results further support the conclusion that the preparation process of the present invention can prepare a high-performance alloy layer. Due to the uniform distribution of Co, Cu, and Sb in the alloy layer, it can be expected that this alloy layer will have better wear resistance, higher strength, and better fatigue resistance. These performance improvements are of great significance for improving the operating efficiency of mechanical equipment and extending its service life. Furthermore, uniformly distributed hard phases such as CoSn2 and (Co,Sn)Sb can further enhance the strengthening effect and improve the hardness and wear resistance of the alloy layer.

[0080] In summary, the surface scan results clearly demonstrate the significant advantages of the preparation process of this invention in achieving the preparation of alloy layers containing Co, ensuring the uniformity of the alloy layer, and improving the performance of the alloy layer, thus proving the effectiveness and advancement of this method in preparing high-performance tin-based Babbitt alloy layers.

[0081] VI. Scanned images of the microstructure of the tin-based Babbitt alloy brazing coating prepared in Example 3, as shown. Figure 4 As shown.

[0082] (1) The surface scan image shows the distribution of Mn (orange) in the alloy layer. It can be seen that Mn is uniformly distributed throughout the alloy layer, indicating that the preparation process of this invention successfully introduces Mn into the alloy layer, realizing the preparation of an alloy layer containing Mn; (2) It can be observed from the surface scan image that the grain size in the alloy layer is small. This is due to the addition of Mn, which provides a large number of nucleation particles and other phase transformation mechanisms during the phase transformation process. Grain refinement helps to improve the strength and toughness of the alloy layer; (3) In addition to Mn, Figure 4 The distribution of Sn (purple), Sb (yellow), and Cu (green) elements is also shown. These elements are uniformly distributed in the alloy layer without obvious aggregation or segregation, indicating that the alloy layer has a uniform composition; (4) Due to the introduction of Mn element and the uniform distribution and grain refinement of elements in the alloy layer, the alloy layer has better mechanical properties.

Claims

1. A method for producing a tin-based Babbitt coating, characterized in that The method comprises the following steps: Step S1, bushing substrate pretreatment; Step S2, alloy powder paste fluid is prepared; Step S3, the alloy powder paste fluid is coated on the surface of the substrate, and is dried to form an alloy powder coating; Step S4, CMT additive welding, the welding wire is melted at high temperature and reacts in situ with the alloy powder coating on the surface of the substrate to synthesize a tin-based babbitt solder coating in situ.

2. The method of producing a tin-based Babbitt coating according to claim 1, characterized in that The bushing substrate pretreatment in step S1 includes oil removal treatment, heating dehydrogenation treatment, and oxidation layer removal treatment.

3. The method of claim 2, wherein the tin-based Babbitt alloy braze coating is prepared by the steps of: At least one of the following technical features is included: (1) The oil removal treatment method in step S1 is to clean the surface of the substrate with acetone or alcohol; (2) The heating dehydrogenation treatment method in step S1 is to heat the substrate to 200-300°C for 1-4 hours; (3) The oxidation layer removal treatment method in step S1 is to use an angle grinder to remove the oxidation layer on the surface of the substrate to expose the fresh metal surface layer; (4) The drying temperature in step S3 is 100-150°C; (5) The coating thickness of the alloy powder paste fluid on the surface of the substrate in step S3 is 0.05-3 mm.

4. The method of claim 1 wherein the tin-based Babbitt alloy braze coating is prepared by the steps of: The alloy powder paste fluid in step S2 includes 55-75 wt% of reinforcing alloy powder, 0.01-3 wt% of binder, 15-20 wt% of volatile solvent, 0.1-0.5 wt% of leveling agent, and the balance of cosolvent.

5. The method of claim 4, wherein the tin-based Babbitt alloy brazing coating is prepared by the steps of: The reinforcing alloy powder is tin-based babbitt alloy powder and / or trace element-containing metal powder.

6. The method of producing a tin-based Babbitt coating according to claim 5, wherein At least one of the following technical features is included: (1) The tin-based babbitt alloy powder is at least one of SnCu alloy powder, SnSb alloy powder, and SnSbCu alloy powder; (2) The trace elements are at least one of Ni, Co, Cr, Si, Mn, Fe, and B; preferably, the addition amounts of the trace elements in the reinforcing alloy powder are as follows: Ni 0-0.5, Co 0-0.5, Cr 0-0.8, Si 0-0.028, Mn 0-0.045, Fe 0-0.03, and B 0-0.003; (3) The trace element-containing metal powder is at least one of trace element-containing tin alloy powder, trace element-containing copper alloy powder, trace element-containing tin elemental powder, and trace element-containing copper elemental powder.

7. The method of producing a tin-based Babbitt coating according to claim 4, wherein At least one of the following technical features is included: (1) The binder is at least one of water glass and polyvinyl alcohol; (2) The volatile solvent is at least one of anhydrous ethanol and n-butanol; (3) The leveling agent is at least one of 0.5 wt% silicone oil and polyether-modified silicone oil; (4) The cosolvent is deionized water.

8. The method of claim 5, wherein the tin-based Babbitt alloy braze coating is prepared by the steps of: At least one of the following technical features is included: (1) The welding wire in step S4 is at least one of SnSb4Cu4, SnSb8Cu4, SnSb8Cu8, and SnSb11Cu6. (2) The welding current in step S4 is 80-145 A, including but not limited to 80 A, 85 A, 90 A, 95 A, 100 A, 105 A, 110 A, 115 A, 120 A, 125 A, 130 A, 135 A, 140 A, 145 A, the wire feeding speed is 6-12 m / min, the welding speed is 6-12 m / min, and the welding seam spacing is 6-12 mm.

9. The method of producing a tin-based Babbitt coating according to claim 8, characterized in that The welding in step S4 is divided into two layers, the first layer is used for base welding in a pulse mode, and the second layer is used for CMT mode.

10. A method of producing a tin-based Babbitt bearing shell, characterized in that The method comprises the following steps: Step A, using the preparation method of the tin-based Babbitt alloy brazing coating in any one of claims 1-9 to synthesize the tin-based Babbitt alloy brazing coating in situ on the bearing bush substrate; Step B, machining the bearing bush to the target size.

Images