A method of forming-welding-machining a steel-based aluminum-tin plain bearing

Abstract

The application discloses a forming-welding-processing method of a steel-based aluminum-tin sliding bearing, and comprises the following steps: step one, a steel-based aluminum-tin alloy layer composite plate is rolled into a shaft sleeve blank with an open gap through a three-roll coiling process; step two, a joint is subjected to a pre-welding cleaning treatment at the joint gap of the shaft sleeve blank; step three, the shaft sleeve blank is installed and fastened on a special welding positioning clamp; step four, laser-arc composite welding is performed along the open gap of the shaft sleeve blank, so that the joint interface is fused to form a weld; and step five, the welded shaft sleeve is assembled on a sliding bearing base and is subjected to finishing processing to a finished product size. Through the laser-arc composite welding technology, the steel-based aluminum-tin alloy sliding bearing is efficiently and integrally formed by welding a 8-14 mm medium-thick plate. The shaft sleeve after welding can be assembled on the bearing base to accurately eliminate the accumulated tolerance, and the finished product size precision and matching performance are ensured.

Description

Technical Field

[0001] This invention relates to the field of sliding bearing manufacturing technology, specifically to a forming-welding-processing method for a steel-based aluminum-tin sliding bearing. Background Technology

[0002] Currently, most wind turbine sliding bearings use copper sleeves or a process of directly cladding copper layers onto the shaft. The biggest drawback is that when resistance changes during blade rotation, the fluid lubrication lines between the friction surfaces of the shaft and the inner surfaces of the gears can easily be disrupted. This problem is usually compensated for by pre-processing, but when calculation errors occur or new on-site conditions arise, the oil film can be damaged, leading to frictional wear. Aluminum-tin bearings are less expensive to produce than copper alloys and can ensure a better oil film formation between the shaft and the sliding sleeve, achieving hydrodynamic motion. Furthermore, based on operating conditions, pre-processing can be performed at the theoretically calculated location of maximum wear, extending the service life of the sleeve.

[0003] However, existing processes still have technical bottlenecks: existing methods mostly use single-machine rolling forming, resulting in poor control accuracy of the roundness of the bushing blank and the interface gap; for medium and thick steel substrates, conventional welding methods are difficult to achieve full penetration, often requiring multiple layers and multiple passes of welding, leading to high heat input and high filler content, which can easily cause overheating and softening of the aluminum-tin layer, and welding deformation is difficult to control; at the same time, conventional processes usually first perform independent precision machining on the bushing before assembling it to the base, which cannot eliminate the cumulative tolerance superposition between bushing machining and base machining, resulting in poor coaxiality and uneven fit clearance of the assembled components. In actual operation, local overload can easily damage the oil film, causing abnormal wear, which is difficult to meet the high reliability and long service life requirements of sliding bearings for high-power wind turbine units.

[0004] Therefore, this invention proposes a forming-welding-processing method for steel-based aluminum-tin sliding bearings, aiming to solve the technical problems in existing processes such as low precision in bushing rolling, high welding heat input leading to overheating and softening of the aluminum-tin alloy layer and difficulty in controlling welding deformation, and the inability of the pre-processing and post-assembly method to eliminate cumulative tolerances, thus affecting the dimensional accuracy of the finished product and the stability of the oil film. Summary of the Invention

[0005] To address the technical problems in existing aluminum-tin sliding bearing manufacturing processes, such as low precision in rolling and forming, difficulty in welding medium-thick plates, and cumulative tolerances resulting from pre-processing and post-assembly methods that affect the dimensional accuracy and oil film stability of finished products, this invention provides a forming-welding-processing method for steel-based aluminum-tin sliding bearings. This method uses three-roll rolling to precisely form the bushing blank, combined with laser-arc composite wire welding to achieve deep melting metallurgical bonding and deformation control of the steel base layer. The welded bushing is then fitted to the bearing base and subjected to overall precision machining. This effectively eliminates welding deformation and forming errors, significantly improving the dimensional accuracy, fit consistency, and bearing service life of the finished product.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a forming-welding-processing method for steel-based aluminum-tin sliding bearings, comprising the following steps: Step 1: Preparation of bushing blank: A steel-based aluminum-tin alloy composite plate is provided as the base material, and it is rolled into a bushing blank with an open gap by a three-roll rolling process. Step 2: Pre-treatment of bushing blank: The interface gap of the bushing blank is cleaned before welding to remove oil and oxide layer; Step 3: Fixing the bushing blank in the fixture: Install and fasten the bushing blank onto the special welding positioning fixture, so that the opening of the bushing blank faces upward, to ensure that the weld pool remains stable and formed under the action of gravity; Step 4, Laser-Arc Hybrid Welding: Laser-arc hybrid welding is performed along the opening gap. A high-energy-density laser beam penetrates deep into the steel base layer to achieve deep penetration and ensure sufficient metallurgical bonding at the substrate interface. At the same time, the gap is filled by continuously fed welding wire and arc heat source, and finally the 8-14mm medium-thick plate is welded and formed to form a steel-based aluminum-tin bushing, resulting in a high-quality weld with beautiful shape and no pores or cracks. Step 5: Assembly of the bushing and sliding bearing: The welded bushing and sliding bearing base are assembled together by interference fit to ensure accurate positioning and tight fit; then, the assembled components are precision machined as a whole, using the sliding bearing base as the installation reference.

[0007] Furthermore, in step one, the step of rolling the bushing blank with an open gap is as follows: the steel-based aluminum-tin alloy composite plate that has been sheared is fed into a three-roll rolling machine, the relative position between the upper roller and the two lower rollers is adjusted so that the composite plate undergoes continuous plastic bending deformation when passing through the roller gap; the downward pressure of the upper roller is controlled to gradually increase so that the plate is gradually rolled into a circle until the two edges form an open gap.

[0008] Furthermore, in step one, the edges at both ends of the plate are pre-bent to ensure that the curvature of the edge position is consistent with the circumferential curvature of the bushing blank, so as to avoid the appearance of straight sections on the edge after rolling, which would affect the joint fitting accuracy; the width of the opening gap is controlled to be 1.2 to 1.5 times the diameter of the welding wire, so as to reserve sufficient forming space for subsequent welding filling.

[0009] Furthermore, in step two, the specific process for pre-welding cleaning of the interface gap of the bushing blank is as follows: mill off the tin layer with a width of 3-8mm on both sides of the joint, and finely polish the interface gap of the bushing blank with fine sandpaper. After polishing, clean it with alcohol to remove oil and oxide layer, and then dry it.

[0010] Furthermore, in step three, the misalignment on both sides of the interface is ensured to be no more than 0.5mm to meet the precision requirements of welding assembly.

[0011] Furthermore, in step four, the laser beam spot is aligned with the center line of the opening gap, and the end of the welding wire of the wire feeding mechanism is pointed to a predetermined offset position behind the laser spot, with an offset position of 4-8 mm, so as to achieve stable melting of the welding wire under the action of the electric arc and effective filling of the gap.

[0012] Furthermore, in step four, in the formed steel-based aluminum-tin bushing, the steel base material is low-carbon steel, and the aluminum-tin alloy layer material is an aluminum-tin alloy with the grade AlSn20Cu; during the laser-arc composite welding, the laser power is 5000-8000 W, the arc current is 210-250 A, the welding speed is 25-40 mm / s, the wire feed speed is 8-11 m / min, and the shielding gas is pure argon.

[0013] Furthermore, in step four, during laser-arc hybrid welding, to avoid excessive laser energy leading to burn-through or molten pool metal loss due to insufficient penetration of the steel substrate, the laser heat input needs to be controlled. The laser beam can penetrate the surface of the steel substrate to form a stable keyhole, achieving a deep penetration effect and ensuring sufficient metallurgical bonding at the steel substrate interface. At the same time, by controlling the upper limit of power, excessive collapse of the molten pool is avoided, ensuring the stability of the welding process and the quality of weld formation.

[0014] Furthermore, in step four, during laser-arc hybrid welding, the arc heat source is used to melt the continuously fed welding wire, and the molten filling of the welding wire achieves metallurgical connection of the open gap in the bushing blank, while simultaneously assisting in the control of the molten pool thermal circulation; the arc welding current used is 210-250 A, and the wire feeding speed is 8-11 m / min. At this time, the arc can stably melt the welding wire, accurately delivering the filler metal to the molten pool behind or to the side of the laser action zone, achieving effective filling of the open gap; at the same time, the preheating effect of the arc can reduce the sensitivity of laser welding to assembly gaps, its slow cooling effect can suppress the tendency of rapid cooling embrittlement of the weld, and the stirring effect of the arc force on the molten pool improves the fluidity of the molten metal, promotes the escape of gas in the molten pool, and finally, in conjunction with laser deep penetration welding, forms a high-quality weld with good penetration and no porosity cracks.

[0015] Furthermore, in step five, the welded steel-based aluminum-tin bushing is assembled with the sliding bearing base through an interference fit; by using the sliding bearing base as a reference for a single clamping process, the cumulative tolerance of welding deformation and rolling error is eliminated, ensuring the coaxiality and fitting accuracy of the bushing outer circle and the base.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses a three-roll rolling process to precisely form a steel-based aluminum-tin alloy composite plate. By controlling the amount of reduction and feed during the rolling process, a bushing blank with small roundness error and uniform interface gap can be obtained, which effectively avoids problems such as misalignment and uneven gap caused by traditional single-machine rolling or free forming.

[0017] (2) This invention employs laser-arc composite welding technology to weld the interface seam of medium-thick steel-based bushings. Addressing the challenge of forming 8-14mm steel-based aluminum-tin medium-thick plate sliding bearings, laser-arc composite welding achieves one-time penetration. Compared to traditional multi-layer, multi-pass welding, heat input is reduced by more than 40%, preventing overheating and softening of the aluminum-tin alloy layer. Furthermore, the method of pre-assembly followed by finishing eliminates accumulated errors in rolling and welding, achieving a coaxiality ≤0.02mm and significantly improving oil film stability. The laser, as the main heat source, achieves deep metallurgical bonding of the steel base layer, ensuring a strong interface fusion. The arc heat source melts the welding wire to fill the gaps and suppresses weld embrittlement through preheating and slow cooling. The synergistic effect of these two technologies not only significantly reduces weld filler volume and welding deformation but also effectively prevents the aluminum-tin alloy layer from softening due to overheating, ultimately resulting in a high-quality weld with good penetration and no porosity cracks.

[0018] (3) In this invention, the welded bushing and the sliding bearing base are assembled together by interference fit, and then the entire assembly is precision machined to the finished size using the base as a reference. This process route can effectively eliminate the cumulative tolerance caused by rolling forming error and welding thermal deformation, ensuring that the bushing and bearing base have good coaxiality and fit clearance after precision machining. In actual operation, this precise fit is conducive to the formation of a stable hydrodynamic oil film, avoiding oil film damage and abnormal wear caused by local overload, significantly extending the service life of the sliding bearing, and meeting the high reliability requirements of complex working conditions such as wind power generation. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram illustrating the forming principle of the three-roll rolling process for steel-based aluminum-tin bushings in this invention.

[0021] Figure 2 a represents the surface morphology of the laser-arc hybrid welding weld in this invention; Figure 2 b represents the back morphology of the laser-arc hybrid welding weld in this invention; Figure 2 c represents the cross-sectional morphology of the laser-arc hybrid welding weld in this invention.

[0022] Figure 3 This is an assembly and machining diagram of the steel-based aluminum-tin sliding bearing in this invention. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0026] This solution provides a forming, welding, and processing method for steel-based aluminum-tin sliding bearings, including the following steps: Step 1: Provide a steel-based aluminum-tin alloy composite plate (the steel substrate is made of low-carbon steel, and the aluminum-tin alloy layer is made of AlSn20Cu aluminum-tin alloy). (Reference) Figure 1 The steel-based aluminum-tin alloy composite plate 1 is fed into a three-roll rolling mill. The relative positions of the upper roller 2 and the two lower rollers 3 and 4 on both sides are adjusted so that the steel-based aluminum-tin alloy composite plate 1 undergoes continuous plastic bending deformation when passing through the roller gap. The downward pressure of the upper roller 2 is controlled to increase gradually so that the steel-based aluminum-tin alloy composite plate 1 is gradually rolled into a bushing 5 until the two sides form an open gap.

[0027] Step 2: Mill off the tin layer with a width of 3-8mm (preferably 4mm) on both sides of the joint of the opening gap, and use fine sandpaper (e.g., higher than #1000) to finely polish the interface gap of the bushing blank. After polishing, clean it with alcohol to remove oil and oxide layer, and blow dry.

[0028] Step 3: Install and fasten the bushing blank onto the dedicated welding positioning fixture, with the opening of the bushing blank facing upwards. At the same time, align the laser beam spot with the center line of the opening, and point the end of the welding wire of the wire feeding mechanism to a predetermined offset position behind the laser spot (in this embodiment, the specific offset position is 4-8 mm, preferably 5 mm). Step 4: Perform laser-arc hybrid welding along the opening gap. Utilize a high-energy-density laser beam to penetrate deep into the steel substrate to achieve deep penetration and ensure sufficient metallurgical bonding at the substrate interface. Simultaneously, continuously fed welding wire and arc heat source fill the gap, ultimately obtaining a high-quality weld with a beautiful shape and free of porosity and cracks. (Refer to...) Figure 2In this embodiment, the laser (fiber laser) selected has a laser power of 5000-8000 W (6500 W is selected in this embodiment), an arc current of 210-250 A (preferably 230 A in this embodiment), a welding speed of 25-40 mm / s (preferably 35 mm / s in this embodiment), a wire feed speed of 8-11 m / min (preferably 9 m / min in this embodiment), and a shielding gas of pure argon.

[0029] The welding wire used has the following composition: carbon: 0.06-0.15 wt%, manganese: 1.40-1.85 wt%, silicon: 0.80-1.15 wt%, phosphorus: ≤0.025 wt%, sulfur: ≤0.035 wt%, copper: ≤0.50 wt%, with the balance being unavoidable impurities; the diameter of the welding wire is 1.2 mm.

[0030] Step 5: Assemble the welded bushings a6 and b7 onto the sliding bearing base 8 using an interference fit, ensuring that the inner wall of the bushing fits evenly with the outer circle of the base and that the axial positioning is accurate; then, clamp the assembled component onto the machine tool, and using the center hole of the sliding bearing base as a reference, perform turning or grinding to finish the outer circle of the bushing to the finished size, referring to... Figure 3 .

[0031] Performance testing of steel-based aluminum-tin sliding bearings: Surface hardness: The hardness of the steel plate and the alloy layer of the obtained steel-based aluminum-tin sheet were tested in accordance with GB / T 230.1 "Metallic materials Rockwell hardness test - Part 1: Test method".

[0032] Table 1 shows the hardness of the steel plate and the hardness of the alloy layer of the obtained steel-based aluminum-tin sheet.

[0033] The performance of the prepared steel-based aluminum-tin sliding bearing was checked according to the following method, and the results are shown in Table 2.

[0034] Tensile strength and yield strength: The tensile strength and yield strength of the steel plate and the tensile strength and yield strength at the weld of the obtained steel-based aluminum-tin plate were tested in accordance with GB / T 6396 "Test Methods for Mechanical and Technological Properties of Composite Steel Plate".

[0035] Table 2 Performance of Steel-Based Aluminum-Tin Sliding Bearings

[0036] Friction coefficient: The friction coefficient of the obtained steel-based aluminum-tin sheet was tested in accordance with GB / T 35083.1 "Tribological properties of bearing materials for sliding bearings - Part 1: Test of metal bearing materials".

[0037] Table 3. Coefficients of friction of steel-based aluminum-tin plates

[0038] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0039] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A forming-welding-processing method for a steel-based aluminum-tin sliding bearing, characterized in that, Includes the following steps: Step 1: Preparation of bushing blank: Using steel-based aluminum-tin alloy composite plate as the base material, roll it into a bushing blank with an open gap; Step 2, Pre-treatment of bushing blank: Clean the interface gaps of the bushing blank before welding to remove oil and oxide layer; Step 3: Fixing the bushing blank in the fixture: Install and fasten the bushing blank onto the welding positioning fixture, so that the opening of the bushing blank faces upward, to ensure that the weld pool remains stable under the action of gravity; Step 4, Laser-Arc Hybrid Welding: Laser-arc hybrid welding is performed along the open gap. The laser beam penetrates deep into the steel base layer to achieve deep penetration and ensure sufficient metallurgical bonding at the substrate interface. At the same time, the gap is filled by continuously fed welding wire and arc heat source, and finally the 8-14mm medium-thick plate is welded and formed to form a steel-based aluminum-tin bushing. Step 5: Assembly of the bushing and sliding bearing: The welded steel-based aluminum-tin bushing is assembled into the predetermined installation position of the sliding bearing base, ensuring that the two are accurately positioned and tightly fitted. Using the sliding bearing base as the installation reference, the assembled components are precision machined as a whole.

2. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step one, the step of rolling the bushing blank with an open gap is as follows: the steel-based aluminum-tin alloy composite plate that has been sheared is fed into a three-roll rolling machine, the relative position between the upper roller and the two lower rollers is adjusted so that the steel-based aluminum-tin alloy composite plate undergoes continuous plastic bending deformation when passing through the roller gap; the downward pressure of the upper roller is controlled to gradually increase so that the bent plate is gradually rolled into a circle until the two edges form an open gap.

3. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step one, the edges at both ends of the plate are pre-bent to ensure that the curvature of the edge position is consistent with the circumferential curvature of the bushing blank, so as to avoid the appearance of straight sections on the edge after rolling, which would affect the joint fitting accuracy; the width of the opening gap is controlled to be 1.2 to 1.5 times the diameter of the welding wire, so as to reserve sufficient forming space for subsequent welding filling.

4. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step two, the pre-welding cleaning process for the interface gap of the bushing blank is as follows: mill off the tin layer with a width of 3-8mm on both sides of the interface gap, and finely polish the interface gap of the bushing blank with fine sandpaper. After polishing, clean it with alcohol to remove oil and oxide layer, and then dry it.

5. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step three, ensure that the misalignment on both sides of the interface does not exceed 0.5mm to meet the precision requirements of welding assembly.

6. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step four, the laser beam spot is aligned with the center line of the opening gap, and the end of the welding wire of the wire feeding mechanism is pointed to a predetermined offset position behind the laser spot, with an offset position of 4-8 mm, so as to achieve stable melting of the welding wire under the action of the electric arc and effective filling of the gap.

7. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step four, the laser used in the laser-arc hybrid welding can be any one of a carbon dioxide laser, a YAG solid-state laser, a fiber laser, or a semiconductor laser; the arc welding machine used can be any one of a gas metal arc welding machine, a gas metal arc welding machine, or a cold metal transfer welding machine.

8. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1 or 7, characterized in that: In step four, the composition of the laser-arc composite welding wire is as follows: carbon: 0.06-0.15 wt%, manganese: 1.40-1.85 wt%, silicon: 0.80-1.15 wt%, phosphorus: ≤0.025 wt%, sulfur: ≤0.035 wt%, copper: ≤0.50 wt%, with the balance being unavoidable impurities; the diameter of the welding wire is 1-1.5 mm.

9. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1 or 7, characterized in that: In step four, in the formed steel-based aluminum-tin bushing, the steel base material is low-carbon steel, and the aluminum-tin alloy layer material is an aluminum-tin alloy with the grade AlSn20Cu. During the laser-arc composite welding, the laser power is 5000-8000 W, the arc current is 210-250 A, the welding speed is 25-40 mm / s, the wire feed speed is 8-11 m / min, and the shielding gas is pure argon.

10. The forming-welding-processing method for a steel-based aluminum-tin sliding bearing according to claim 1, characterized in that: In step five, the welded steel-based aluminum-tin bushing is assembled with the sliding bearing base through an interference fit; the cumulative tolerance of welding deformation and rolling error is eliminated by a single clamping process based on the sliding bearing base, ensuring the coaxiality and fitting accuracy of the bushing outer circle and the base.

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