A bismuth bronze composite wire for arc cladding of sliding bearings, its preparation process and application

Abstract

The invention discloses a bismuth bronze composite wire for arc cladding of sliding bearings, its preparation process and application, belonging to the technical field of alloy materials. The bismuth bronze composite wire comprises a two-layer structure. By weight percentage, the inner core structure is tin bronze, wherein the Sn content is 4.36% - 7.24%, and the balance is Cu; the outer layer structure is a tin-bismuth binary alloy layer, wherein the Sn content is 30% - 70% wt, and the Bi content is 30% - 70% wt. Through the improvement of the composition and process, the invention separates copper and bismuth in the wire structure to prepare a composite welding wire. Specifically, the wire cross-section is divided into a two-layer structure according to the melting point. The inner core is high-melting-point and high-strength tin bronze, and the outer layer is low-melting-point and low-strength tin-bismuth binary alloy; and the low-melting-point outer layer material is compounded on the inner core tin bronze by a liquid-phase channel continuous compounding process.

Description

Technical Field

[0001] The present invention relates to a bismuth bronze composite wire for arc cladding of sliding bearings, its preparation process and application, belonging to the technical field of alloy materials. Background Art

[0002] Due to the immiscibility of copper and bismuth in bismuth bronze, the relatively soft bismuth is distributed on the copper matrix and has a self-lubricating effect. Therefore, as a bearing alloy material, it has a small friction coefficient and excellent wear resistance, and has good application prospects. At present, the main research and development directions of bismuth bronze materials are bismuth bronze powder materials and bismuth bronze wire materials. When laser cladding is carried out using bismuth bronze powder materials, the disadvantages are that due to the high reflectivity of copper-based materials to laser and the influence of powder utilization rate, there are still obvious defects such as efficiency and porosity in laser cladding of copper-based materials. Arc cladding has better thermal efficiency and more advantages in the cladding processing of copper-based materials. However, there are technical bottlenecks in the research and development of bismuth bronze wire materials required for arc cladding: the existing form of bismuth in bismuth bronze is a single-phase, which often enriches at the grain boundaries of the copper phase, resulting in a decrease in the strength of bismuth bronze materials and a decrease in processing plasticity. Therefore, brittle fracture is extremely likely to occur during the wire forming process, and the wire processing is extremely difficult. Summary of the Invention

[0003] Aiming at the problem of extremely easy brittle fracture during the forming process of bismuth bronze wire materials in the prior art, the purpose of the present invention is to provide a preparation process for a bismuth bronze composite wire for arc cladding of sliding bearings. Through the improvement of composition and process, copper and bismuth are separated in the wire structure to prepare a composite welding wire. Specifically, the wire cross-section is divided into two-layer structure according to the melting point. The inner core is high-melting-point and high-strength tin bronze, and the outer layer is low-melting-point and low-strength tin-bismuth binary alloy; and the low-melting-point outer layer material is compounded on the inner core tin bronze by a liquid-phase channel continuous compounding process.

[0004] Meanwhile, the present invention provides a bismuth bronze composite wire for arc cladding of sliding bearings.

[0005] Meanwhile, the present invention provides an application of the bismuth bronze composite wire for arc cladding of sliding bearings in bearing alloys.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A bismuth bronze composite wire for arc cladding of sliding bearings, the bismuth bronze composite wire includes a two-layer structure, by weight percentage,

[0008] The inner core structure is tin bronze, where the Sn content is 4.36%-7.24%, and the balance is Cu;

[0009] The outer layer structure is a tin-bismuth binary alloy layer, where the Sn content is 30%-70% wt and the Bi content is 30%-70% wt.

[0010] A preparation process of a bismuth bronze composite wire for arc cladding of a sliding bearing includes the following steps:

[0011] S1, Pass a tin bronze welding wire through a tin bath.

[0012] S2, Start a local cooling device for local supercooling process.

[0013] S3, Inject a tin-bismuth alloy liquid into the tin bath.

[0014] S4, After the tin-bismuth alloy liquid around the tin bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, start the laser-arc directional energy deposition device. After forming a liquid-phase channel centered on the tin bronze welding wire in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process, the tin bronze welding wire starts to move downward at a speed of 5 mm / s - 15 mm / s; control the size of the bottom hole aperture of the liquid-phase channel by adjusting the laser energy to control the wire diameter of the bismuth bronze composite welding wire; the tungsten needle electrode is a moving electrode that moves in a circle around the tin bronze welding wire, the distance between the tungsten needle electrode and the tin bronze welding wire is 6 - 8 mm, and the rotation speed is 40 - 80 r / min.

[0015] S5, Draw the diameter of the bismuth bronze composite welding wire to 0.8 - 1.6 mm through a drawing process to obtain a bismuth bronze composite wire for arc cladding of a sliding bearing.

[0016] Preferably, the temperature of the local supercooling process is 40 - 45 °C.

[0017] Preferably, the diameter of the tin bronze welding wire is 2 - 4 mm.

[0018] Preferably, the Sn content in the tin-bismuth alloy liquid is 30%-70% wt, the Bi content is 30%-70% wt, and the depth of the tin-bismuth alloy liquid in the tin bath is 5 mm - 10 mm.

[0019] Preferably, for the laser-arc composite directional energy deposition process, the laser power is 300 W - 600 W, the arc current is 60 A - 70 A, the voltage is 11 V - 12 V, and the directionality means that the arc acts on the solid-phase tin-bismuth alloy zone in a fixed direction, and the laser acts on the bottom hole direction in a fixed direction.

[0020] An arc cladding process of a bismuth bronze composite wire for arc cladding of a sliding bearing, with a current of 90 A, a voltage of 12 V, a swing frequency of 0.6 Hz, a swing amplitude width of 25 mm, and a speed of 6 cm / min.

[0021] The arc cladding layer obtained by the arc cladding process of the present invention, by weight percentage, has the following composition: Bi: 2.17 - 5.66%, Sn: 6.43 - 11.76%, and the balance is Cu.

[0022] Preferably, the arc cladding layer obtained by the arc cladding process of the present invention further includes one or more of Cr, Zr, Ti, and P. By weight percentage, the total content of one or more of Cr, Zr, Ti, and P is 0.05 - 0.08%.

[0023] Application of a bismuth bronze composite wire for arc cladding of sliding bearings in bearing alloys.

[0024] Preferably, 40 - 45°C constant temperature circulating cooling water is passed through the cooling device.

[0025] Preferably, the tin bronze welding wire is 2 - 4 mm, the thickness of the tin - bismuth alloy layer after compounding is 0.04 - 0.08 mm, and when drawn to 0.8 - 1.6 mm, the thickness of the tin - bismuth alloy is 0.015 - 0.03 mm.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. Currently, there is no mature technology for preparing bismuth bronze welding wires. Similar to this technical solution is the tin alloy immersion plating technology for photovoltaic solder tapes, which immerses the solder tape coated with a soldering flux into the tin alloy liquid to be immersed, and the solder tape moves quickly, so that a layer of tin alloy liquid is plated on the surface. However, in such immersion plating technologies, first, the combination between the solder tape and the tin alloy liquid is weak, and the tin alloy layer is likely to fall off. Second, the thickness of the immersed tin alloy layer is very thin, generally 2μm - 5μm, and it is difficult to break through the thickness limit, which limits the composition design space of the composite welding wire and has no practical application value. In fact, current coating or plating technologies can only prepare coatings or platings with micro - nano - level thickness, and there is no effective solution for millimeter - level coatings or platings. This technical solution first realizes the cooling and solidification of the tin - bismuth alloy liquid around the tin bronze welding wire through local liquid - phase supercooling, and at the same time uses the laser - arc directional energy deposition technology to promote the remelting of the solidified tin - bismuth alloy liquid to form a liquid - phase channel as the movement channel of the tin bronze welding wire. And the diameter of the composite welding wire is controlled by controlling the size of the bottom hole of the liquid - phase channel with laser energy. When the tin bronze welding wire passes through the liquid - phase channel, the tin - bismuth alloy and the tin bronze welding wire are compounded under the action of the arc. At this time, the bismuth bronze composite welding wire can not only obtain a sufficient thickness of the tin - bismuth alloy to meet the composition design requirements, but also achieve a high - strength combination between the tin - bismuth alloy and the tin bronze, preventing the tin - bismuth alloy layer from falling off during subsequent drawing and use of the composite welding wire.

[0028] 2. The bismuth bronze composite welding wire has a low-melting-point and high-fluidity tin-bismuth alloy layer on the outer layer of the tin bronze welding wire, which significantly improves the wetting and spreading at the edge of the molten pool during the arc cladding process, thereby improving the edge wetting of the single-pass cladding layer and greatly reducing the pore defects caused by lap joint between adjacent passes before and after arc cladding.

[0029] 3. The addition of trace alloying elements such as Cr, Zr, Ti, and P is beneficial to improving the quality of the arc cladding layer of the composite welding wire. The tendency of pore formation in the cladding layer added with these trace elements is significantly reduced, and at the same time, the oxidation resistance is enhanced during the cladding process, and the oxide film on the surface of the cladding layer is reduced.

[0030] 4. The bismuth bronze composite wire obtained by the present invention has good processing plasticity and will not undergo brittle fracture during the wire forming process.

[0031] 5. The present invention forms a solid phase region by locally cooling the tin-bismuth alloy liquid, and forms a liquid phase channel through a laser arc in the solid phase region. The arc melts the solid phase tin-bismuth alloy on the one hand and composites the tin-bismuth alloy and the tin bronze welding wire on the other hand. The main function of the laser is to form an appropriate bottom hole size to obtain the required composite welding wire diameter. At this time, the wire diameter consistency is difficult to meet the requirements of the welding wire diameter for use, and strict and precise control of the wire diameter is required through drawing. The Bi and Cu are separated by the above method to make a welding wire, and then a bismuth bronze / steel bimetallic material is made through the arc cladding process.

[0032] 6. The arc energy in the liquid phase channel region of the present invention forms a metallurgical bond between the tin-bismuth alloy and the surface of the tin bronze welding wire while melting the tin-bismuth alloy. Since the diameter of the tin bronze welding wire is relatively thin and the melting point of the tin-bismuth alloy is relatively low, if the arc acts for a long time, it is easy to cause the melting of the tin bronze welding wire and the rapid melting of the tin-bismuth alloy to the bottom hole, resulting in difficulty in forming an ideal liquid phase channel. Too low arc energy will also greatly reduce the arc stability. Therefore, the tungsten electrode is a moving electrode that moves in a circular motion around the tin bronze welding wire. The distance between the tungsten electrode and the tin bronze welding wire is 6-8 mm, and the rotation speed is 40-80 r / min. At this time, the bismuth bronze composite welding wire continuously compounded through the liquid phase channel can not only obtain a sufficient thickness of the tin-bismuth alloy to ensure that the composition meets the design requirements, but also achieve a high-strength bond between the tin-bismuth alloy and the tin bronze, preventing the tin-bismuth alloy layer from falling off during the subsequent drawing and use of the composite welding wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic cross-sectional structure diagram of the bismuth bronze composite wire of the present invention;

[0034] Figure 2 is a schematic diagram of the preparation process of the present invention;

[0035] Figure 3It is the microstructure diagram of the arc cladding layer of bismuth bronze with 2% Bi content of the present invention;

[0036] Figure 4 It is the microstructure diagram of the arc cladding layer of bismuth bronze with 3% Bi content of the present invention;

[0037] Figure 5 It is the microstructure diagram of the arc cladding layer of bismuth bronze with 4% Bi content of the present invention;

[0038] Figure 6 It is the microstructure diagram of the arc cladding layer of bismuth bronze with 6% Bi content of the present invention;

[0039] Figure 7 It is the microstructure diagram of the metallographic defect of the process of omitting the tungsten needle electrode in Comparative Example 1;

[0040] Figure 8 It is the metallographic microstructure diagram of Example 1 of the present invention;

[0041] Figure 9 It is the microstructure diagram of the metallographic defect of laser cladding. Detailed implementation manners

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0043] Example 1

[0044] As Figure 1 shown, a bismuth bronze composite wire for arc cladding of a sliding bearing includes two-layer structure: the inner core structure is a tin bronze welding wire, and the outer layer structure is a tin-bismuth binary alloy layer. The Sn content of the tin bronze welding wire is 7.24% wt, and the balance is Cu. The Sn content of the tin-bismuth alloy is 70% wt, and the Bi content is 30% wt.

[0045] As Figure 2 shown, a preparation process of a bismuth bronze composite wire for arc cladding of a sliding bearing includes the following steps:

[0046] S1, passing a tin bronze welding wire with a diameter of 2 mm through a tin bath;

[0047] S2, turning on a local cooling device for local supercooling process; the set temperature of the supercooling device is 40 °C;

[0048] S3, injecting a tin-bismuth alloy liquid into the tin bath. The Sn content of the tin-bismuth alloy liquid is 70% wt, and the Bi content is 30% wt. The depth of the tin-bismuth alloy liquid in the tin bath is 10 mm;

[0049] S4. After the tin-bismuth alloy liquid around the tin bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, the laser-arc directional energy deposition device is turned on. After a liquid-phase channel centered on the tin bronze welding wire is formed in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process (laser power 500 W, arc current 60 A, voltage 12 V), the tin bronze welding wire starts to move downward at a speed of 10 mm / s through the tin-bismuth alloy liquid-phase channel; the size of the bottom hole aperture of the liquid-phase channel is controlled by adjusting the laser energy to control the wire diameter of the bismuth bronze composite welding wire; the tungsten electrode is a moving electrode that moves in a circular motion around the tin bronze welding wire, the distance between the tungsten electrode and the tin bronze welding wire is 6 mm, and the rotation speed is 40 r / min; the thickness of the tin-bismuth alloy layer after compounding is 0.04 mm.

[0050] S5. The diameter of the bismuth bronze composite welding wire is drawn to 0.8 mm through the drawing process, and the thickness of the tin-bismuth alloy layer after drawing is 0.015 mm; a bismuth bronze composite wire for arc cladding of sliding bearings is obtained.

[0051] The arc cladding process parameters of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment are: current 90 A, voltage 12 V, swing frequency 0.6 Hz, swing amplitude width 25 mm, speed 6 cm / min.

[0052] The composition of the arc cladding layer of the bismuth bronze composite wire obtained in this embodiment is: the Sn content is 11.76% wt, the Bi content is 2.17% wt, the Cr content is 0.05% wt, and the balance is Cu.

[0053] The application of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment in bearing alloys.

[0054] As Figure 3 shown, it can be seen in the attached drawing of Embodiment 1 that the Bi phase in the arc cladding layer is uniformly dispersed in fine spherical shapes, proving that the composition of the tin-bismuth alloy layer of the composite welding wire is uniform and the thickness is consistent. As Figure 8 shown, it is the metallographic microstructure diagram of Embodiment 1. The arc cladding layer obtained in this embodiment has no porosity defects.

[0055] Embodiment 2

[0056] A bismuth bronze composite wire for arc cladding of sliding bearings includes a two-layer structure: the inner core structure is a tin bronze welding wire, and the outer layer structure is a tin-bismuth binary alloy layer. The Sn content of the tin bronze welding wire is 5.95% wt, and the balance is Cu. The Sn content of the tin-bismuth alloy is 60% wt, and the Bi content is 40% wt.

[0057] A preparation process of a bismuth bronze composite wire for arc cladding of sliding bearings includes the following steps:

[0058] S1. Pass a 4-mm-diameter tin bronze welding wire through the tin bath.

[0059] S2. Turn on the local cooling device to perform the local subcooling process; set the temperature of the subcooling device to 45 °C.

[0060] S3. Inject a tin-bismuth alloy liquid into the tin bath. The Sn content in the tin-bismuth alloy liquid is 60% wt, and the Bi content is 40% wt. The depth of the tin-bismuth alloy liquid in the tin bath is 5 mm.

[0061] S4. After the tin-bismuth alloy liquid around the tin bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, turn on the laser-arc directional energy deposition device. After forming a liquid-phase channel centered on the tin bronze welding wire in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process (laser power 300 W, arc current 70 A, voltage 11 V), the tin bronze welding wire starts to move downward at a speed of 5 mm / s through the tin-bismuth alloy liquid-phase channel; control the size of the bottom hole aperture of the liquid-phase channel by adjusting the laser energy to control the wire diameter of the bismuth bronze composite welding wire; the tungsten needle electrode is a moving electrode that moves in a circular motion around the tin bronze welding wire. The distance between the tungsten needle electrode and the tin bronze welding wire is 8 mm, and the rotation speed is 80 r / min; the thickness of the tin-bismuth alloy layer after composite is 0.08 mm.

[0062] S5. Draw the diameter of the bismuth bronze composite welding wire to 1.6 mm through the drawing process. After drawing, the thickness of the tin-bismuth alloy layer is 0.03 mm to obtain the bismuth bronze composite wire for arc cladding of sliding bearings.

[0063] The arc cladding process parameters of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment are: current 90 A, voltage 12 V, swing frequency 0.6 Hz, swing amplitude width 25 mm, and speed 6 cm / min.

[0064] The composition of the arc cladding layer of the bismuth bronze composite wire obtained in this embodiment is: Sn content is 9.95% wt, Bi content is 3.07% wt, Cr content is 0.02% wt, Zr content is 0.02% wt, Ti content is 0.02% wt, P content is 0.02% wt, and the balance is Cu.

[0065] Application of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment in bearing alloys.

[0066] As Figure 4 shown, it can be seen in the attached drawing of Embodiment 2 that the Bi phase in the arc cladding layer is evenly dispersed in fine spherical shapes, proving that the composition of the tin-bismuth alloy layer of the composite welding wire is uniform and the thickness is consistent. As the Bi content increases, the size of the Bi phase increases.

[0067] Embodiment 3

[0068] A bismuth bronze composite wire for arc cladding of sliding bearings, comprising a two-layer structure: the inner core structure is a tin bronze welding wire, and the outer layer structure is a tin-bismuth binary alloy layer. The Sn content of the tin bronze welding wire is 4.36% wt, and the balance is Cu. The Sn content of the tin-bismuth alloy is 50% wt, and the Bi content is 50% wt.

[0069] A preparation process for a bismuth bronze composite wire for arc cladding of sliding bearings, comprising the following steps:

[0070] S1, Pass a 3-mm-diameter tin bronze welding wire through a tin bath;

[0071] S2, Start a local cooling device for local supercooling process; the set temperature of the supercooling device is 45°C;

[0072] S3, Inject a tin-bismuth alloy liquid into the tin bath. The Sn content of the tin-bismuth alloy liquid is 50% wt, and the Bi content is 50% wt. The depth of the tin-bismuth alloy liquid in the tin bath is 8 mm;

[0073] S4, After the tin-bismuth alloy liquid around the tin bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, start the laser-arc directional energy deposition device. After forming a liquid-phase channel centered on the tin bronze welding wire in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process (laser power 600 W, arc current 65 A, voltage 11 V), the tin bronze welding wire starts to move downward at a speed of 15 mm / s through the liquid-phase channel of the tin-bismuth alloy; control the size of the bottom hole aperture of the liquid-phase channel by adjusting the laser energy to control the wire diameter of the bismuth bronze composite wire; the tungsten needle electrode is a moving electrode that moves in a circle around the tin bronze welding wire. The tungsten needle electrode is 7 mm away from the tin bronze welding wire, and the rotation speed is 50 r / min; the thickness of the tin-bismuth alloy layer after compounding is 0.06 mm;

[0074] S5, Draw the diameter of the bismuth bronze composite welding wire to 1.00 mm through a drawing process. After drawing, the thickness of the tin-bismuth alloy layer is 0.022 mm; obtain a bismuth bronze composite wire for arc cladding of sliding bearings.

[0075] The arc cladding process parameters of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment are: current 90 A, voltage 12 V, swing frequency 0.6 Hz, swing amplitude width 25 mm, speed 6 cm / min.

[0076] The composition of the arc cladding layer of the bismuth bronze composite wire obtained in this embodiment is that the Sn content is 7.86% wt, the Bi content is 3.84% wt, and the balance is Cu.

[0077] The application of a bismuth bronze composite wire for arc cladding of sliding bearings in this embodiment in bearing alloys.

[0078] As Figure 5As shown, in the attached drawing of Example 3, it can be seen that the Bi phase in the arc cladding layer is evenly dispersed in fine spherical shapes, proving that the composition of the tin-bismuth alloy layer of the composite wire is uniform and the thickness is consistent. As the Bi content increases, the size of the Bi phase further increases and the distribution becomes denser.

[0079] Example 4

[0080] A bismuth bronze composite wire for arc cladding of sliding bearings, comprising a two-layer structure: the inner core structure is a tin bronze welding wire, and the outer layer structure is a tin-bismuth binary alloy layer. The Sn content of the tin bronze welding wire is 4.36% wt, and the balance is Cu. The Sn content of the tin-bismuth alloy is 30% wt, and the Bi content is 70% wt.

[0081] A preparation process for a bismuth bronze composite wire for arc cladding of sliding bearings, comprising the following steps:

[0082] S1, passing a tin bronze welding wire with a diameter of 3.5 mm through a tin bath;

[0083] S2, starting a local cooling device for local supercooling process; the set temperature of the supercooling device is 40 °C;

[0084] S3, injecting a tin-bismuth alloy liquid into the tin bath. The Sn content in the tin-bismuth alloy liquid is 30% wt, the Bi content is 70% wt, and the depth of the tin-bismuth alloy liquid in the tin bath is 10 mm;

[0085] S4, after the tin-bismuth alloy liquid around the tin bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, starting a laser-arc directional energy deposition device. After forming a liquid-phase channel centered on the tin bronze welding wire in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process (laser power 500 W, arc current 60 A, voltage 12 V), the tin bronze welding wire starts to move downward at a speed of 10 mm / s through the liquid-phase channel of the tin-bismuth alloy; controlling the size of the bottom hole aperture of the liquid-phase channel by adjusting the laser energy to control the wire diameter of the bismuth bronze composite welding wire; the tungsten needle electrode is a moving electrode that moves in a circular motion around the tin bronze welding wire. The distance between the tungsten needle electrode and the tin bronze welding wire is 6 mm, and the rotation speed is 60 r / min; the thickness of the tin-bismuth alloy layer after compounding is 0.07 mm;

[0086] S5, drawing the diameter of the bismuth bronze composite wire to 0.9 mm through a drawing process. After drawing, the thickness of the tin-bismuth alloy layer is 0.027 mm; obtaining a bismuth bronze composite wire for arc cladding of sliding bearings.

[0087] The arc cladding process parameters of a bismuth bronze composite wire for arc cladding of sliding bearings using this example are: current 90 A, voltage 12 V, swing frequency 0.6 Hz, swing amplitude width 25 mm, speed 6 cm / min.

[0088] The composition of the arc cladding layer of the bismuth bronze composite wire obtained in this embodiment is that the Sn content is 6.43% wt, the Bi content is 5.66% wt, and the balance is Cu.

[0089] Application of a bismuth bronze composite wire for arc cladding of a sliding bearing in a bearing alloy in this embodiment.

[0090] As Figure 6 shown, in the attached drawing of Embodiment 4, it can be seen that the Bi phase in the arc cladding layer is evenly dispersed in fine spherical shapes, proving that the composition of the tin-bismuth alloy layer of the composite welding wire is uniform and the thickness is consistent. The decrease in the Sn content causes the melting point of the alloy to rise and the alloy solidification to accelerate, and the size of the Bi phase does not further increase, but is densely distributed in fine particle phases.

[0091] Comparative Example 1

[0092] Compared with Embodiment 1, Comparative Example 1 omits the tungsten needle electrode process, and the rest are the same. Compared with Embodiment 1, the arc cladding layer in Comparative Example 1 is prone to porosity defects (as shown specifically in Figure 7 ).

[0093] Comparative Example 2

[0094] As Figure 9 shown, when laser cladding copper alloy powder, porosity defects are prone to occur in the cladding layer due to factors such as the scattering of the laser by the copper alloy and the oxidation of the powder itself.

[0095] It should be understood that in order to streamline the present disclosure and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting the intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the claims, the inventive aspects lie in less than all the features of the previously disclosed embodiments. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the present invention.

[0096] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field will understand, based on the above description, that other embodiments can be envisioned within the scope of the present invention thus described. In addition, it should be noted that the language used in this specification is mainly selected for the purpose of readability and teaching, rather than for the purpose of explaining or limiting the subject matter of the present invention. Therefore, many modifications and changes will be obvious to those of ordinary skill in this technical field without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

[0097] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A process for preparing bismuth bronze composite wire for arc cladding of sliding bearings, characterized in that: The bismuth bronze composite wire comprises a two-layer structure, calculated by weight percentage: The inner core structure is tin bronze, with Sn content of 4.36%-7.24% and the balance being Cu; The outer layer structure is a tin-bismuth binary alloy layer, wherein the Sn content is 30%-70%wt, and the Bi content is 30%-70%wt; Preparation process The following steps are involved: S1, pass the tin bronze wire through the tin bath; S2, start the local cooling device to perform a local supercooling process; S3, injecting tin-bismuth alloy liquid into the tin bath; S4, after the tin-bismuth alloy liquid around the tin-bronze welding wire solidifies to form a solid-phase tin-bismuth alloy zone, the laser-arc directional energy deposition device is turned on, and a liquid phase channel centered on the tin-bronze welding wire is formed in the solidified tin-bismuth alloy through the laser-arc composite directional energy deposition process, and the tin-bronze welding wire begins to move from top to bottom at a speed of 5mm / s-15mm / s; the size of the bottom hole of the liquid phase channel is controlled by adjusting the laser energy to control the wire diameter of the bismuth-bronze composite welding wire; the tungsten needle electrode is a moving electrode that performs a circular motion around the tin-bronze welding wire, the tungsten needle electrode is 6-8mm away from the tin-bronze welding wire, and the rotation speed is 40-80r / min; S5, drawing the bismuth-bronze composite welding wire to a diameter of 0.8-1.6 mm through a drawing process to obtain a bismuth-bronze composite wire for arc cladding of sliding bearings.

2. The preparation process according to claim 1, characterized in that: The temperature of the local supercooling process is 40-45°C.

3. The preparation process according to claim 1, characterized in that: The diameter of tin bronze welding wire is 2-4mm.

4. The preparation process according to claim 1, characterized in that: The Sn content in the tin-bismuth alloy liquid is 30%-70%wt, the Bi content is 30%-70%wt, and the depth of the tin-bismuth alloy liquid in the tin bath is 5mm-10mm.

5. The preparation process according to claim 1, characterized in that: The laser power of the laser-arc composite directional energy deposition process is 300W-600W, the arc current is 60A-70A, and the voltage is 11V-12V. The directional method is that the arc acts fixedly toward the solid phase tin-bismuth alloy area, and the laser acts fixedly toward the bottom hole direction.

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