A tin-based babbitt bearing and a method for producing the same

Abstract

The present application relates to the technical field of sliding bearing manufacturing, in particular to a tin-based babbitt bearing shell and a preparation method thereof. The preparation method comprises the following steps: cleaning the inner surface of the bearing shell body, then preparing a tin pool layer on the inner surface to obtain a tin pool body; pouring and casting the babbitt alloy after melting, applying ultrasonic vibration to perform degassing treatment after pouring and casting, then performing directional cooling to sequentially solidify the alloy melt from outside to inside to obtain a babbitt alloy layer preform; assembling the tin pool body and the babbitt alloy layer preform and then performing diffusion welding. The method can uniformly form the babbitt alloy layer and firmly combine the babbitt alloy layer with the bearing shell body, thereby improving the performance of the bearing shell, reducing the production cost and improving the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of sliding bearing manufacturing technology, and more specifically, to a tin-based Babbitt alloy bearing and its preparation method. Background Technology

[0002] Bearing bushes are the core components of sliding bearings, and their performance directly affects transmission stability. Tin-based Babbitt alloys are widely used in the manufacture of high-end bearing bushes due to their excellent anti-friction and wear-resistant properties. Currently, mainstream manufacturing technologies include gravity casting, centrifugal casting, and CMT additive manufacturing. Gravity casting relies on the gravity of the liquid metal to fill and solidify; centrifugal casting uses the centrifugal force generated by the high-speed rotation of the mold to spread and shape the melt; CMT additive manufacturing is based on the principle of cold metal transfer, using a pre-set path to drive a welding torch to deposit molten welding wire droplets layer by layer onto the substrate surface, which then solidifies to form a Babbitt alloy layer.

[0003] However, existing mainstream manufacturing technologies for tin-based Babbitt alloy bearings all have inherent defects, making it difficult to meet the comprehensive performance requirements of high-end equipment. While gravity casting is relatively simple, the low filling rate and long solidification time of the liquid metal easily lead to internal defects such as porosity and looseness. Furthermore, the solidified interface between the Babbitt alloy and the matrix results in insufficient bonding strength, making it difficult to meet the performance requirements of high-end bearings and leading to its gradual phasing out. Centrifugal casting, currently the dominant technology, is prone to radial segregation of elements with large density differences, such as antimony and copper, in the liquid alloy under centrifugal force, directly deteriorating the bearing's load-bearing stability and service life. Simultaneously, its filling and solidification processes have poor controllability, requiring significant machining allowances to ensure dimensional accuracy, resulting in a material utilization rate of only 60%-70% and high production costs. While CMT additive manufacturing technology can improve compositional uniformity, it relies on high-precision CNC systems and dedicated welding power supplies, requiring substantial initial equipment investment. Moreover, its layer-by-layer deposition molding method demands precise control of multiple welding parameters, and auxiliary processes such as interlayer insulation further extend the production cycle.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for preparing tin-based Babbitt alloy bearings. The method involves preparing a Babbitt alloy layer preform using ultrasonic vibration degassing and directional solidification processes, followed by tinning of the bearing substrate. The Babbitt alloy layer preform is then diffusion-welded to the tinned bearing substrate. This method enables the Babbitt alloy layer to be uniformly formed and to bond firmly to the bearing substrate, thereby improving bearing performance while reducing production costs and increasing production efficiency.

[0006] The second objective of this invention is to provide a tin-based Babbitt alloy bearing, which is prepared by the tin-based Babbitt alloy bearing method described above.

[0007] 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 bearing includes the following steps: The inner surface of the bearing substrate is cleaned, and then a platinum tin layer is prepared on its inner surface to obtain a platinum tin substrate; After the Babbitt alloy is melted and cast, ultrasonic vibration is applied to degas the material after casting. Then, directional cooling is performed to solidify the alloy melt sequentially from the outside to the inside, thus obtaining a Babbitt alloy layer preform. The platinum tin substrate is assembled with the Babbitt alloy layer preform, so that the Babbitt alloy layer preform is in contact with the platinum tin layer, and then diffusion soldering is performed.

[0008] Preferably, the material of the tin plating layer includes In 0.001wt%~0.06wt%, Ge 0.001wt%~0.008wt%, Zr 0.01wt%~0.08wt%, Co 0.01wt%~0.2wt%, Ni 0.4wt%~0.7wt%, with the balance being tin.

[0009] Preferably, the thickness of the platinum tin layer is 0.5~1.0 mm.

[0010] Preferably, the preparation process of the platinum tin layer includes the following steps: The cleaned bearing substrate is preheated, and flux is applied to the inner surface of the bearing substrate and the end of the welding rod. The end of the welding rod coated with flux is brought into contact with the inner surface of the bearing substrate, and the end of the welding rod is moved along the inner surface of the bearing substrate. The preheating heat of the bearing substrate is used to partially melt the welding rod, forming a platinum tin layer on the inner surface of the bearing substrate.

[0011] Preferably, the flux comprises 5wt%~15wt% ammonium chloride, 20wt%~55wt% zinc chloride, 20wt%~3.5wt% CdCl2, 0wt%~6wt% SnCl2·2H2O, 5wt%~15wt% H3PO4, 0.05wt%~3wt% LiCl, and the balance being distilled water.

[0012] Preferably, the Babbitt alloy comprises at least one of ZSnSb8Cu4, ZSnSb11Cu6, ZSnSb9Cu7, and ZSnSb12Cu6Cd1.

[0013] Preferably, the ultrasonic vibration frequency is 20~40kHz and the vibration time is 3~5min.

[0014] Preferably, the heating temperature for diffusion welding is 250~280℃, and the holding time is 30~60min.

[0015] Preferably, the apparatus for preparing the Babbitt alloy layer preform includes: An outer cylindrical mold and a central positioning post disposed within the outer cylindrical mold, forming a cavity for casting an annular Babbitt alloy layer between the outer cylindrical mold and the central positioning post; the central positioning post is connected to a heating mechanism for keeping the melt warm during the casting process; It also includes an ultrasonic vibration mechanism for applying ultrasonic vibration to the melt after casting; the outer circumference of the outer mold is provided with a cooling mechanism for directional cooling of the melt from the outside to the inside.

[0016] Preferably, the central positioning post is provided with a crossbar, the two ends of which are disposed on the top surface of the outer circular mold, for supporting the central positioning post and fixing it inside the outer circular mold.

[0017] Preferably, the bottom of the outer circular mold is provided with a baffle that can move relative to the outer circular mold, and a receiving box is provided below the baffle.

[0018] A tin-based Babbitt alloy bearing is prepared by the tin-based Babbitt alloy bearing preparation method described in any one of the aforementioned embodiments.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The method of this invention employs directional solidification and ultrasonic vibration degassing and impurity removal processes to prepare the Babbitt alloy layer preform, effectively reducing defects such as porosity, looseness, and oxide inclusions. Furthermore, it significantly improves the uniformity, density, and grain refinement of the metallographic structure of the Babbitt alloy layer, providing a reliable microstructure basis for the high load-bearing capacity, wear resistance, and long service life of the bearing. Then, diffusion welding achieves a strong bond between the Babbitt alloy layer preform and the tin-plated matrix. The resulting bearing exhibits excellent interfacial bonding strength, Brinell hardness, and performance stability, providing reliable performance assurance for the high load-bearing capacity, wear resistance, and long service life of the bearing. Attached Figure Description

[0020] 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.

[0021] Figure 1 A schematic diagram illustrating the manufacturing process of tin-based Babbitt alloy bearings provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the apparatus for preparing the Babbitt alloy layer provided in an embodiment of the present invention; Figure 3 These are physical images of the Babbitt alloy layer preforms in Embodiment 1 and Comparative Example 3 of the present invention; Figure 4 This is a metallographic diagram of the Babbitt alloy layer in Embodiment 1 of the present invention; Figure 5 This is a metallographic diagram of the Babbitt alloy layer in Embodiment 2 of the present invention; Figure 6 These are interface morphology diagrams of tin-based Babbitt alloy bearings in Embodiments 1 and 3 of the present invention; the left diagram is for Embodiment 3, and the right diagram is for Embodiment 1. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and 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.

[0023] like Figure 1 As shown, the first aspect of the present invention provides a method for preparing a tin-based Babbitt alloy bearing, comprising the following steps: The inner surface of the bearing substrate is cleaned, and then a platinum tin layer is prepared on the inner surface of the substrate to obtain a platinum tin substrate; After the Babbitt alloy is melted and cast, ultrasonic vibration is applied to degas the material after casting. Then, directional cooling is performed to solidify the alloy melt sequentially from the outside to the inside, thus obtaining a Babbitt alloy layer preform. The platinum base is assembled with the Babbitt alloy layer preform, so that the Babbitt alloy layer preform comes into contact with the platinum base, and then diffusion soldering is performed.

[0024] This invention employs a process combining directional cooling and ultrasonic vibration for degassing and impurity removal to prepare a Babbitt alloy layer preform with uniform microstructure, high density, and fine grain refinement. Then, diffusion welding is used to achieve a strong bond between the Babbitt alloy layer preform and the tin-based substrate. The resulting tin-based Babbitt alloy bearing exhibits significantly better interfacial bonding strength, Brinell hardness, and performance stability than conventional gravity casting processes, providing reliable performance assurance for the bearing's high load-bearing capacity, wear resistance, and long service life.

[0025] Compared with conventional gravity casting, the Babbitt alloy microstructure prepared by the process of this invention has the following advantages: (1) Significantly improved microstructure uniformity: In conventional gravity casting, the melt cools naturally under a disordered temperature field, which easily leads to the specific gravity segregation of Sb and Cu elements, forming local coarse primary phase aggregation and segregation bands; while the present invention adopts a directional cooling process, which controls the solidification process through a stable unidirectional temperature gradient, combined with ultrasonic vibration for degassing and impurity removal, effectively suppressing element segregation and achieving a uniform and dispersed distribution of precipitated phases, significantly improving the microstructure uniformity; (2) Significantly improved microstructure density: Due to insufficient degassing of the melt and disordered solidification feeding in conventional gravity casting, dispersed pores and micropores often exist in the metallographic structure. Porosity and shrinkage defects; the present invention effectively eliminates casting defects such as porosity and looseness through the synergistic effect of ultrasonic vibration degassing and directional sequential solidification feeding, significantly improving the density of the structure and providing a guarantee for the bearing performance and service stability of the bearing; (3) Significant grain refinement effect: the disordered cooling method of conventional gravity casting easily leads to disordered grain growth, forming coarse columnar crystals or dendrites, and obvious anisotropy of the structure; the combined effect of the directional temperature field and ultrasonic vibration of the present invention, on the one hand, inhibits disordered grain growth through a stable temperature gradient, and on the other hand, breaks up the primary dendrites and promotes nucleation through ultrasonic vibration, realizing uniform grain refinement, significantly enhancing the isotropy of the structure, and greatly reducing the fluctuation of mechanical properties. The metallographic structure of the Babbitt alloy layer preform prepared by the method of the present invention is significantly better than that of conventional gravity casting process in terms of uniformity, density and grain refinement, providing a reliable microstructure basis for the high load-bearing capacity, wear resistance and long service life of the bearing.

[0026] During the diffusion welding stage, the Babbitt alloy layer preform and the platinum tin layer on the surface of the bearing substrate diffuse into each other, forming a strong metallurgical bond. This invention achieves uniform forming of the Babbitt alloy layer and a strong bond with the bearing substrate through the synergistic effect of substrate platinum tin pretreatment, ultrasonic vibration degassing and directional sequential solidification to prepare the Babbitt alloy layer preform, and diffusion welding. This effectively improves the performance and production efficiency of the bearing and reduces production costs.

[0027] In some specific embodiments of the present invention, the material of the plating tin layer includes In 0.001wt%~0.06wt%, Ge 0.001wt%~0.008wt%, Zr 0.01wt%~0.08wt%, Co 0.01wt%~0.2wt%, Ni 0.4wt%~0.7wt%, with the balance being tin. In and Ge can reduce the surface tension of the tin layer and improve the wettability of the tin layer with the substrate and Babbitt metal; Co and Ni can form intermetallic compounds with the substrate material to enhance interfacial bonding; Zr can refine the grains of the plating tin layer, improve the hardness and wear resistance of the tin layer itself, and combine with trace amounts of oxygen in the melt to form stable ZrO2, removing free oxygen in the tin layer, preventing tin layer oxidation, and improving the bonding purity between the tin layer and the substrate.

[0028] In some embodiments, typically but not limitingly, for example, the In content in the tin plating layer can be any one value or a range of any two values ​​from 0.001wt%, 0.01wt%, 0.03wt%, 0.06wt%; the Ge content can be any one value or a range of any two values ​​from 0.001wt%, 0.003wt%, 0.005wt%, 0.008wt%; the Zr content can be any one value or a range of any two values ​​from 0.01wt%, 0.03wt%, 0.05wt%, 0.08wt%; the Co content can be any one value or a range of any two values ​​from 0.01wt%, 0.05wt%, 0.1wt%, 0.15wt%, 0.2wt%; and the Ni content can be any one value or a range of any two values ​​from 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%.

[0029] In some specific embodiments of the present invention, the thickness of the platinum tin layer is 0.5~1.0mm, for example, it can be any one value or a range of any two values ​​among 0.5mm, 0.6mm, 0.8mm, and 1.0mm.

[0030] In some specific embodiments of the present invention, the preparation process of the tin plating layer includes the following steps: After cleaning, the bearing substrate is preheated. Flux is applied to the inner surface of the bearing substrate and the end of the welding rod. The end of the welding rod coated with flux is brought into contact with the inner surface of the bearing substrate, and the end of the welding rod is moved along the inner surface of the bearing substrate. The preheating heat of the bearing substrate is used to locally melt the welding rod, forming a platinum tin layer on the inner surface of the bearing substrate.

[0031] In some specific embodiments of the present invention, the flux includes 5wt%~15wt% ammonium chloride, 20wt%~55wt% zinc chloride, 20wt%~3.5wt% CdCl2, 0wt%~6wt% SnCl2·2H2O, 5wt%~15wt% H3PO4, 0.05wt%~3wt% LiCl, and the balance being distilled water. The ammonium chloride and zinc chloride components in the flux can remove surface oxide films, while H3PO4 can improve the flux's fluidity and slightly remove minute oxides from the substrate surface. Without the addition of phosphoric acid, the flux's fluidity deteriorates, making it impossible to evenly cover the contact area between the solder electrode and the substrate during coating. This can easily lead to missed areas and uneven thickness in the tin plating layer. Furthermore, the minute oxide points cannot be removed, resulting in localized bonding defects and a decline in the bonding quality of the tin plating layer.

[0032] In some embodiments, typically but not limitingly, for example, the mass percentage of ammonium chloride in the flux can be any one of 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, or a range of any two of these values; the mass percentage of zinc chloride can be any one of 20wt%, 30wt%, 40wt%, 55wt%, or a range of any two of these values; the mass percentage of CdCl2 can be any one of 0wt%, 1wt%, 2wt%, 3wt%, 3.5wt%, or a range of any two of these values; the mass percentage of SnCl2·2H2O can be any one of 0wt%, 2wt%, 4wt%, 6wt%, or a range of any two of these values; the mass percentage of H3PO4 can be any one of 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, or a range of any two of these values; and the mass percentage of LiCl can be any one of 0.05wt%, 1wt%, 2wt%, 3wt%, or a range of any two of these values.

[0033] In some specific embodiments of the present invention, the cleaning treatment of the inner surface of the bearing substrate includes: grinding, pickling, and alkaline washing of the bearing substrate to remove surface oxide scale and simultaneously remove rust and oil. As an example, the cleaning steps specifically include: grinding the inner surface of the bearing substrate with 120-200 grit sandpaper to remove surface oxide scale and burrs; then immersing the bearing substrate in a 10%-15% hydrochloric acid solution for 20-30 minutes to remove surface rust; after pickling, immersing it in a 5%-8% sodium hydroxide solution for 15-20 minutes to remove surface oil; finally rinsing thoroughly with running water for later use.

[0034] In some specific embodiments of the present invention, after preparing a platinum tin layer on the inner surface of the clean bearing substrate, the following steps are also included: first, the inner surface of the bearing substrate is washed with hot water to remove residual flux; then, it is placed in a Na2CO3 solution to neutralize for 5-10 minutes to eliminate acidic substances in the residual flux; subsequently, it is rinsed with running water to remove chloride ions and avoid interface corrosion caused by residual chloride ions, and then dried for later use.

[0035] In some specific embodiments of the present invention, the Babbitt alloy includes at least one of ZSnSb8Cu4, ZSnSb11Cu6, ZSnSb9Cu7, and ZSnSb12Cu6Cd1.

[0036] In some specific embodiments of the present invention, the melting temperature of Babbitt alloy is 450~550°C, for example, it can be any one value or a range of any two values ​​among 450°C, 480°C, 500°C, 520°C, and 550°C; the holding time is 20~30 min, for example, it can be any one value or a range of any two values ​​among 20 min, 23 min, 25 min, 28 min, and 30 min.

[0037] In some specific embodiments of the present invention, the vibration frequency of the ultrasonic vibration is 20~40kHz, for example, it can be any single value or a range of any two values ​​among 20kHz, 25kHz, 30kHz, 35kHz, and 40kHz; the vibration time is 3~5min, for example, it can be any single value or a range of any two values ​​among 3min, 3.5min, 4min, 4.5min, and 5min. Ultrasonic vibration removes gas from the melt and promotes impurities such as oxide scale to float to the surface of the melt.

[0038] In some specific embodiments of the present invention, the heating temperature for diffusion welding is 250~280℃, for example, it can be any one value or a range of any two values ​​among 250℃, 260℃, 270℃, and 280℃; the holding time is 30~60min, for example, it can be any one value or a range of any two values ​​among 30min, 40min, 50min, and 60min.

[0039] In some specific embodiments of the present invention, the method further includes a step of turning the bearing blank after diffusion welding to remove excess Babbitt alloy layer and residual parts at the edge of the bearing substrate, so that the dimensional accuracy and surface roughness of the bearing meet the design requirements, and finally obtain a high-performance tin-based Babbitt alloy bearing.

[0040] like Figure 2 As shown, in some specific embodiments of the present invention, the apparatus for preparing the Babbitt alloy layer preform includes: An outer cylindrical mold 1 and a central positioning post 2 disposed within the outer cylindrical mold 1 form a cavity for casting an annular Babbitt alloy layer. The inner wall of the outer cylindrical mold 1 is smooth to ensure the accuracy of the outer surface of the preform. The central positioning post 2 is connected to a heating mechanism for heat preservation of the melt during the casting process. As an example, the heating mechanism includes a temperature control box 3. The central positioning post 2 has a heating channel inside and is connected to the temperature control box 3 through a heat transfer medium pipe. The temperature control box 3 provides stable heat to the central positioning post 2 to achieve precise temperature control. It also includes an ultrasonic vibration mechanism 4, whose output end is connected to the outer wall of the outer cylindrical mold 1, for applying ultrasonic vibration to the melt after casting is completed; the outer periphery of the outer cylindrical mold 1 is provided with a cooling mechanism 5 for directional cooling of the melt from the outside to the inside.

[0041] In some specific embodiments of the present invention, a crossbar 6 is provided on the central positioning post 2, and the two ends of the crossbar 6 are placed on the top surface of the outer circular mold 1 to support the central positioning post 2 and press it tightly and fix it in the outer circular mold 1 to ensure the stability of the cavity size.

[0042] In some specific embodiments of the present invention, the bottom of the outer cylindrical mold 1 is provided with a baffle 7 that can move relative to the outer cylindrical mold 1 to close the bottom of the cavity. As an example, the baffle 7 is slidably engaged with the inner wall of the outer cylindrical mold 1 and can be pulled out in the horizontal direction under the action of the driving mechanism to realize the discharge of the unsolidified melt. A receiving box 8 is provided below the baffle 7 to receive and recycle the unsolidified Babbitt alloy melt discharged from the cavity.

[0043] In some specific embodiments of the present invention, the central positioning column 2 is heated to 450~480°C before casting. For example, it can be any one value or a range of any two values ​​among 450°C, 460°C, 470°C, and 480°C to ensure that the melt does not solidify rapidly during casting.

[0044] In some specific embodiments of the present invention, a cooling mechanism 5 is arranged around the outer cylindrical mold 1, and has a cooling channel inside. The cooling channel is connected to an external cooling medium supply device to transfer cold energy to the outer cylindrical mold 1, thereby achieving directional cooling of the melt. As an example, the cooling mechanism 5 is a water-cooling mechanism. The present invention achieves directional cooling of the Babbitt alloy melt from the outside to the inside through the cooling mechanism 5 arranged around the outer cylindrical mold 1, forming a chilled inner lining layer perpendicular to the inner layer of the bearing substrate. Directional cooling can make the temperature gradient uniform during melt solidification, effectively refine the grains, and avoid the problems of compositional segregation and coarse grains caused by centrifugal force in centrifugal casting. Grain refinement can significantly improve the hardness, wear resistance, and toughness of the material.

[0045] The Babbitt alloy layer preform preparation device provided by this invention has a simple structure, requiring no complex components such as high-speed drives and high-precision CNC, resulting in low initial investment. During production, preforms can be prepared in batches, and the unsolidified melt can be recycled, increasing material utilization to over 90%. Simultaneously, the diffusion welding and machining processes are simple, and a single set of equipment can achieve continuous batch production with high efficiency. Furthermore, the directional solidification and ultrasonic vibration degassing and impurity removal steps effectively reduce defects such as porosity, looseness, and oxide inclusions, significantly improving the yield.

[0046] A second aspect of the present invention provides a tin-based Babbitt alloy bearing, which is prepared by the method described in any of the foregoing embodiments.

[0047] The following detailed description of some embodiments of the present invention is provided in conjunction with specific application examples. Unless otherwise specified, all raw materials used in the embodiments can be obtained commercially available.

[0048] Example 1 (1) Cleaning treatment of the inner surface of the bearing substrate Select Q235 steel bearing substrate, and polish the inner surface with 150-grit sandpaper; immerse in 12wt% hydrochloric acid solution for 25 minutes, then immerse in 6wt% sodium hydroxide solution for 20 minutes, and rinse thoroughly with running water for later use. (2) Tin plating The composition of the tin-based soldering electrode is: In 0.003wt%, Ge 0.005wt%, Co 0.1wt%, Ni 0.5wt%, Zr 0.02wt%, with the balance being tin; The flux composition is as follows: 10wt% ammonium chloride, 40wt% zinc chloride, 2wt% CdCl2, 3wt% SnCl2·2H2O, 10wt% H3PO4, 1.5wt% LiCl, with the balance being distilled water; With the pre-treated bearing substrate facing upwards and horizontal, the prepared plating flux is placed in a container, and tin-based solder rods are cut to 30-50cm lengths. A medium-frequency induction heating device is used to heat the bearing substrate, with a thermometer monitoring the inner surface temperature in real time. The temperature is raised to 260℃ and maintained to ensure uniform substrate temperature without localized overheating. Plating flux is evenly applied to the area to be tinned on the inner surface of the bearing substrate using a brush, and also applied to the end of the solder rod, ensuring full flux coverage at the contact point between the solder rod and the substrate. Holding the solder rod, the end is used in a spiral coating motion along the inner surface of the substrate. The low-melting-point solder rod melts naturally upon contact with the heated substrate. Flux is continuously replenished (when flux is insufficient, it is replenished using a container with a nozzle on the side), ensuring even spreading of the molten tin. During the coating process, the tin layer thickness is monitored in real time using an online thickness gauge, with the thickness in some areas approaching 0.8mm. During this process, reduce the coating speed and repeatedly apply light coatings to level the surface, ensuring that the thickness of the tin plating layer on the entire inner surface is within the range of 0.8±0.05mm. After the tin plating layer is fully coated, maintain the substrate temperature at 260℃ for 5 minutes to allow the molten tin plating layer to flow fully and eliminate tiny air bubbles during the coating process. Then, turn off the heating device and allow the tin plating layer to cool down slowly with the substrate to below 100℃ to complete the tin plating process. (3) Post-tinning First, wash the inner surface of the tin-based substrate with 60℃ hot water, then immerse it in a 2wt% Na2CO3 solution for 8 minutes, rinse with running water, and check if the chloride ion content in the rinse water is qualified (determine the chloride content in the water quality according to GBT 11896-89 Determination of Chloride in Water Quality by silver nitrate titration method, and judge it as qualified when the chloride content is equivalent to that in tap water), and dry it with hot air at 120℃ for later use; (4) Preparation of Babbitt alloy layer preform ZSnSb11Cu6 Babbitt alloy was selected and melted at 520℃ for 25 minutes. The central positioning post was heated to 460℃. The Babbitt alloy melt, which had passed the temperature holding period, was poured into the cavity between the outer mold and the central positioning post at a uniform rate of 80 ml / s, ensuring that the melt completely filled the mold cavity. The ultrasonic vibration mechanism was activated to perform ultrasonic vibration treatment on the melt in the mold. The ultrasonic vibration frequency was 30 kHz and the vibration time was 4 minutes. The water cooling mechanism was turned on, and the cooling water circulated around the outer mold, so that the melt was cooled directionally from the outside to the inside (along the direction of the outer mold towards the central positioning post). When the outer layer thickness reached 12 mm, the baffle was removed and the unsolidified melt was recovered. After cooling to room temperature, the Babbitt alloy layer preform was taken out. (5) Assembly and diffusion welding The Babbitt alloy layer preform is placed into the inner hole of the split tin-plated bearing base. The coaxiality of the preform and the bearing base is adjusted to ensure uniform gap. Then, the positioning bolts on the split bearing base are tightened to achieve fixed assembly of the preform and the bearing base. The assembled structure is placed in a 260℃ heating box and kept at that temperature for 45 minutes to allow the tin layer on the surface of the Babbitt alloy layer preform and the bearing base to diffuse into each other and form a strong metallurgical bonding layer. (6) Machining The bearing blank after diffusion bonding is machined to remove excess Babbitt alloy layer and residual parts at the edge of the bearing substrate, so that the dimensional accuracy and surface roughness of the bearing meet the design requirements, and the finished bearing is obtained.

[0049] Example 2 (1) Cleaning treatment of the inner surface of the bearing substrate Select Q235 steel bearing substrate, and polish the inner surface with 200-grit sandpaper; immerse in 12wt% hydrochloric acid solution for 20 minutes, then immerse in 8wt% sodium hydroxide solution for 15 minutes; rinse thoroughly with running water and set aside. (2) Tin plating The composition of the tin-based soldering electrode is: In 0.005wt%, Ge 0.008wt%, Co 0.2wt%, Ni 0.7wt%, Zr 0.05wt%, with the balance being tin; The flux composition is: 15wt% ammonium chloride, 55wt% zinc chloride, 6wt% SnCl2·2H2O, 15wt% H3PO4, 3wt% LiCl, with the balance being distilled water; The bearing substrate is heated to 280°C, and the tin plating layer thickness is 1.0 mm. The specific tin plating steps are the same as in Example 1. (3) Post-tinning Same as Example 1; (4) Preparation of Babbitt alloy layer preform ZSnSb8Cu4 Babbitt alloy was selected and melted at 550℃ for 30 minutes. The central positioning post was heated to 480℃. The Babbitt alloy melt, which had passed the temperature holding period, was uniformly poured into the cavity between the outer mold and the central positioning post, ensuring that the melt completely filled the mold cavity. The pouring speed was 80 ml / s. The ultrasonic vibration mechanism was activated to perform ultrasonic vibration treatment on the melt in the mold. The ultrasonic vibration frequency was 40 kHz and the vibration time was 5 minutes. The water cooling mechanism was turned on, and the cooling water circulated around the outer mold, so that the melt was directionally cooled from the outside to the inside. When the outer layer thickness reached 15 mm, the baffle was removed and the unsolidified melt was recovered. After cooling to room temperature, the Babbitt alloy layer preform was taken out. (5) Assembly and diffusion welding The assembly steps are the same as in Example 1; during the diffusion welding process, the heating box temperature is 280℃ and the holding time is 60 minutes. (6) Machining Same as Example 1.

[0050] Example 3 The preparation process of this comparative example is basically the same as that of Example 1, except that in step (2), the tin-based solder electrode composition is In 0.003wt%, Ge 0.005wt%, Ni 0.5wt%, Zr 0.02wt%, with the balance being tin (i.e., without Co). The remaining process steps and parameters are the same as those of Example 1.

[0051] Comparative Example 1 Tin-based Babbitt alloy uses ZSnSb11Cu6; The bearing substrate is made of Q235 steel; The bearing bush was prepared using traditional gravity casting, which differs from Example 1 in that: ultrasonic vibration, directional cooling, and diffusion welding were not performed; the bearing bush substrate was degreased and derusted, then coated with flux; the substrate was preheated and then tin-immersed (using pure tin); the preheated core was assembled and fixed to the steel back of the steel bearing bush substrate; subsequently, molten tin-based Babbitt alloy was slowly poured into the mold under its own gravity; the casting was allowed to cool naturally and solidify, and finally, the finished bearing bush was obtained through machining and non-destructive testing.

[0052] Comparative Example 2: Tin-based Babbitt alloy uses ZSnSb8Cu4; The bearing substrate is made of Q235 steel; The bearing bush was prepared using traditional gravity casting, which differs from Example 2 in that: ultrasonic vibration, directional cooling, and diffusion welding were not performed; the bearing bush substrate was degreased and derusted, then coated with flux; the substrate was preheated and then tin-immersed (using pure tin); the preheated core was assembled and fixed to the steel back of the steel bearing bush substrate; subsequently, molten tin-based Babbitt alloy was slowly poured into the mold under its own gravity; the casting was allowed to cool naturally and solidify, and finally, the finished bearing bush was obtained through machining and non-destructive testing.

[0053] Comparative Example 3 The overall process, raw materials, and parameters of this comparative example are basically the same as those of Example 1. The only difference is that ultrasonic vibration was not performed in step (4), while the other process steps and parameters are the same as those of Example 1.

[0054] Test case (1) The Brinell hardness of the Babbitt alloy layer in each embodiment and comparative example was tested respectively. The test results are shown in Table 1.

[0055] Table 1. Brinell hardness of the Babbitt alloy layer in each embodiment and comparative example.

[0056] The Brinell hardness test results in Table 1 show that the Babbitt alloy layer in the examples exhibits higher hardness and better performance stability. In Example 1, the average Brinell hardness of SnSb11Cu6 is 29.14 HBW, significantly higher than the 27.12 HBW of the conventional gravity casting comparative example, representing a hardness increase of approximately 7.4%. Comparative Example 3, which was not ultrasonically treated, has an uneven microstructure, resulting in significantly lower hardness stability compared to Example 1. In Example 2, the average Brinell hardness of SnSb8Cu4 is 25.06 HBW, higher than the 23.82 HBW of the conventional gravity casting comparative example, representing a hardness increase of approximately 5.2%. Furthermore, the hardness data of the examples shows minimal fluctuation, indicating that the Babbitt alloy prepared by this process has good microstructure uniformity, with no obvious elemental segregation, coarse dendrites, or porosity defects. Its high and stable hardness significantly improves the wear resistance and anti-galling performance of the bearing, extending its service life under high-load conditions.

[0057] (2) The interfacial bonding strength between the Babbitt alloy layer and the bearing substrate in each embodiment and comparative example was tested respectively. The test was conducted according to GB / T 12948—1991 "Destructive Test Method for Bimetallic Bond Strength of Sliding Bearings". The test results are shown in Table 2.

[0058] Table 2

[0059] As shown in Table 2, the interfacial bonding strength test results indicate that the tin-based Babbitt alloy bearings prepared by this invention exhibit significantly higher interfacial bonding strength than bearings prepared using conventional gravity casting processes. Specifically, the average interfacial bonding strength of the SnSb11Cu6 bearing in Example 1 is 72.6 MPa, and the average interfacial bonding strength of the SnSb8Cu4 bearing in Example 2 is 63.74 MPa; while the average interfacial bonding strengths of the SnSb11Cu6 and SnSb8Cu4 bearings prepared using conventional gravity casting processes are only 36.34 MPa and 31.88 MPa, respectively. This comparison demonstrates that the synergistic effect of customized plating treatment, ultrasonic vibration degassing, directional solidification, and diffusion welding significantly strengthens the metallurgical bond between the steel backing and the Babbitt alloy layer. Compared to traditional gravity casting, the interfacial bonding strength is increased by approximately 100%, effectively avoiding the risk of alloy layer detachment and peeling during bearing service, and significantly improving the bearing's load-bearing capacity and service reliability.

[0060] The tin-based Babbitt alloy bearing prepared in this embodiment of the invention has significantly better performance than conventional gravity casting processes in terms of interfacial bonding strength and Brinell hardness, and its performance is stable, providing a reliable performance guarantee for the bearing's high load-bearing capacity, wear resistance and long service life.

[0061] Furthermore, a comparison between Examples 1 and 3 shows that adding Co to the tin plating layer can significantly improve the interfacial bonding strength between the Babbitt alloy layer and the bearing substrate. Figure 6 The left image shows the interface morphology without Co in Example 3. As can be seen from the metallographic image, the interface between the Co-free steel backing substrate and the platinum tin layer is uneven, and there is no continuous and uniform intermetallic compound transition layer. Gaps and micropores appear locally at the interface, and the degree of atomic interpenetration is low. Only a small amount of discontinuous intermetallic compound is formed by Ni. The interface bonding is weak, and cracks are very easy to initiate and propagate along the interface when subjected to shear loads. Figure 6 The right figure in the figure shows the interface morphology of the addition of Co element in Example 1. The metallographic image shows that, under the synergistic effect of Co and Ni, a uniform and continuous intermetallic compound transition layer (the area between the two dashed lines in the figure) is generated between the steel backing substrate and the platinum tin layer. The interface is tightly bonded and there are no defects such as gaps or micropores. Co element promotes the formation of Fe-Ni-Co-Sn multi-element intermetallic compounds, accelerates the interdiffusion of interfacial atoms, and achieves a strong metallurgical bond.

[0062] like Figure 3As shown, Comparative Example 3 did not undergo ultrasonic degassing during the preparation of the Babbitt alloy layer preform. The surface of the preform contained numerous pores of varying sizes and significant oxide inclusions. Internal cross-section analysis also revealed continuous pores and a loose structure. Subsequent bonding with the bearing substrate resulted in increased interface defects and poor overall casting quality. In contrast, Example 1, due to ultrasonic degassing, had a smooth and flat surface with no visible pores or inclusions. After cross-section, the internal structure was dense with no obvious casting defects, resulting in excellent casting quality. Furthermore, the data in Table 2 shows that Comparative Example 3, lacking ultrasonic treatment, exhibited uneven microstructure and significant fluctuations in bonding strength.

[0063] like Figure 4 and Figure 5 As shown, in Example 1, the precipitates are uniformly dispersed in the tin-based solid solution matrix in a fine, regular blocky morphology, without localized agglomeration, coarse dendrites, or long needle-like structures. The precipitates are small in size and have a high degree of uniformity in distribution, with no obvious gravity segregation. In Example 2, the precipitates are distributed in a dense, uniform short needle-like morphology, without the continuous network, dendritic, or coarse needle-like structures commonly found in conventional gravity casting. The precipitates are well-uniformly distributed and do not form obvious segregation bands.

[0064] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a tin-based Babbitt alloy bearing, characterized in that, Includes the following steps: The inner surface of the bearing substrate is cleaned, and then a platinum tin layer is prepared on its inner surface to obtain a platinum tin substrate; After the Babbitt alloy is melted and cast, ultrasonic vibration is applied to degas the material after casting. Then, directional cooling is performed to solidify the alloy melt sequentially from the outside to the inside, thus obtaining a Babbitt alloy layer preform. The platinum tin substrate is assembled with the Babbitt alloy layer preform, so that the Babbitt alloy layer preform is in contact with the platinum tin layer, and then diffusion soldering is performed.

2. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, It meets at least one of the following characteristics: (1) The material of the platinum tin layer includes In 0.001wt%~0.06wt%, Ge 0.001wt%~0.008wt%, Zr 0.01wt%~0.08wt%, Co 0.01wt%~0.2wt%, Ni 0.4wt%~0.7wt%, with the balance being tin; (2) The thickness of the platinum tin layer is 0.5~1.0mm.

3. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, The preparation process of the platinum tin layer includes the following steps: The cleaned bearing substrate is preheated, and flux is applied to the inner surface of the bearing substrate and the end of the welding rod. The end of the welding rod coated with flux is brought into contact with the inner surface of the bearing substrate, and the end of the welding rod is moved along the inner surface of the bearing substrate. The preheating heat of the bearing substrate is used to partially melt the welding rod, forming a platinum tin layer on the inner surface of the bearing substrate.

4. The method for preparing the tin-based Babbitt alloy bearing according to claim 3, characterized in that, The flux comprises 5wt%~15wt% ammonium chloride, 20wt%~55wt% zinc chloride, 0wt%~3.5wt% CdCl2, 0wt%~6wt% SnCl2·2H2O, 5wt%~15wt% H3PO4, 0.05wt%~3wt% LiCl, and the balance being distilled water.

5. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, The Babbitt alloy includes at least one of ZSnSb8Cu4, ZSnSb11Cu6, ZSnSb9Cu7, and ZSnSb12Cu6Cd1.

6. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, The ultrasonic vibration frequency is 20~40kHz, and the vibration time is 3~5min.

7. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, The heating temperature for diffusion welding is 250~280℃, and the holding time is 30~60min.

8. The method for preparing tin-based Babbitt alloy bearings according to claim 1, characterized in that, The apparatus for preparing the Babbitt alloy layer preform includes: An outer cylindrical mold and a central positioning post disposed within the outer cylindrical mold, forming a cavity for casting an annular Babbitt alloy layer between the outer cylindrical mold and the central positioning post; the central positioning post is connected to a heating mechanism for keeping the melt warm during the casting process; It also includes an ultrasonic vibration mechanism for applying ultrasonic vibration to the melt after casting; the outer circumference of the outer mold is provided with a cooling mechanism for directional cooling of the melt from the outside to the inside.

9. The method for preparing tin-based Babbitt alloy bearings according to claim 8, characterized in that, It meets at least one of the following characteristics: (1) A crossbar is provided on the central positioning column, and the two ends of the crossbar are set on the top surface of the outer circular mold to support the central positioning column and fix it inside the outer circular mold; (2) The bottom of the outer circular mold is provided with a baffle that can move relative to the outer circular mold, and a receiving box is provided below the baffle.

10. A tin-based Babbitt alloy bearing, characterized in that, The tin-based Babbitt alloy bearing was prepared using the method described in any one of claims 1 to 9.

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