Heterogeneous bearing ring piece interface multi-field construction forming manufacturing method

Abstract

The invention discloses a heterogeneous bearing ring interface multi-field construction forming manufacturing method, which comprises the following steps of: performing laser cladding on an outer ring material on the surface of an inner ring of a bearing ring, then performing hot rolling deformation, setting partitions for the bearing ring, and respectively contacting electrodes with the inner ring and the outer ring according to the partitions to apply electromagnetic pulses, the inner ring and the outer ring are made of two different materials. Through the light-heat-force-electricity multi-field synergistic effect, atomic-scale interface combination of the heterogeneous bearing ring piece is achieved, a high-performance heterogeneous interface is obtained while the heterogeneous bearing ring piece is formed, and the combination strength and performance of the heterogeneous interface of the wind power sliding bearing are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bearing manufacturing, and particularly relates to a method for multi-field construction and forming manufacturing of heterogeneous bearing ring interfaces. Background Art

[0002] Wind power generation is an important way for China to achieve the "dual carbon" goal. Offshore wind power has become a key area for countries to compete in development. Bearings are the core components of wind turbines, directly determining the service performance and power generation efficiency of wind turbines. With the power upgrade of large-megawatt wind turbines, the load on bearings has increased exponentially, and they need to face extreme working conditions such as alternating heavy loads, high humidity, and salt spray corrosion, posing extreme requirements for the wear resistance and corrosion resistance of bearings. Traditional main wind power bearings often adopt rolling bearing structures. Compared with rolling bearings, sliding bearing structures are simpler, have stronger load-bearing capacities, and are more adaptable to complex offshore working conditions. "Replacing rolling with sliding" has become the forefront direction for the development of future wind power bearings.

[0003] Due to the excellent corrosion resistance, anti-wear, and heat conduction performance characteristics of copper alloys, laser cladding of copper alloys on the bearing surface has become an effective way to solve the wear resistance and corrosion resistance of main wind power bearings, that is, copper alloys are cladded on the surface layer to improve corrosion resistance and wear resistance, while the bearing steel material is still retained in the core to ensure the load-bearing capacity of the bearing bush. However, the surface copper alloy formed by this process is a cast structure, with loose defects resulting in insufficient material density. In addition, the thermal physical property parameter gradient of copper / steel heterogeneous materials changes suddenly, resulting in poor interfacial bonding force, which severely restricts the engineering application of sliding bearings. It can be seen that for this forefront direction of wind power sliding bearings, the existing heterogeneous material construction methods in the world have prominent problems of poor tissue state and poor interfacial bonding. How to achieve atomic-level bonding at the interface of copper alloy / bearing heterogeneous rings is the core problem in the development of a new generation of wind power sliding bearings. Summary of the Invention

[0004] In view of this, the present invention proposes a method for multi-field construction and forming manufacturing of heterogeneous bearing ring interfaces. Copper alloy is laser cladded on the surface of a bearing steel matrix, and hot rolling deformation is used to promote atomic diffusion and metallurgical bonding at the interface between the copper alloy and the bearing steel matrix. Then, electromagnetic pulses are used to further promote atomic bonding and lattice matching at the interface between the copper alloy and the bearing matrix, ultimately achieving atomic-level bonding at the interface of high-density copper alloy / bearing steel. This new method is expected to solve the problem of poor interfacial bonding of high-wear-resistant and corrosion-resistant sliding bearings.

[0005] The technical solution of the present invention is realized as follows:

[0006] In a first aspect, the present invention provides a method for multi-field construction forming manufacturing of a heterogeneous bearing ring interface. The outer ring material is laser cladded on the inner ring surface of the bearing ring, and then hot rolling deformation is carried out. The bearing ring is partitioned, and electromagnetic pulses are applied to the bearing ring according to the partitions respectively to obtain a heterogeneous bearing ring, wherein the inner ring and the outer ring are made of two different materials.

[0007] By controlling the surface texture and texture of the bearing ring, the surface is completely wetted during the solid-liquid bonding process of laser cladding, and the degree of interface morphology fitting is better.

[0008] Laser cladding is carried out under a protective atmosphere to avoid the formation of harmful oxides due to the contact of the interface with air. By controlling parameters such as laser power, scanning speed, spot diameter, and powder feeding rate, a part of the bearing steel on the surface of the bearing ring is melted, and the laser cladded copper alloy fits better with the curved surface of the bearing ring, and partial metallurgical bonding between the copper alloy and the bearing steel has been achieved.

[0009] Through the thermal-mechanical action during the hot rolling deformation process, the laser cladding layer is transformed from a cast structure to a forged structure, improving the performance of the laser cladding layer; during the hot rolling deformation process, coordinated plastic deformation occurs at the interface between the copper alloy layer and the bearing steel matrix, further increasing the interface contact area and mechanical interlocking; at the same time, during the high-temperature deformation process, the copper alloy layer and the bearing steel matrix are fully softened at high temperature, reducing the energy barrier for atomic diffusion and promoting the thermal motion and mutual diffusion of atoms.

[0010] Through electromagnetic pulse loading, current is passed through the interface area to generate flow-through and flow-around effects, forming a local high-energy field in the interface area, triggering electron migration and lattice vibration at the copper alloy / bearing steel matrix interface, promoting the formation of interface atomic bonding and the matching adjustment of the lattice, eliminating possible small gaps and mismatched areas at the interface, and realizing atomic-level bonding of the high-density copper alloy / bearing steel heterogeneous interface, thereby significantly improving the bonding strength and performance of the heterogeneous interface of the wind power sliding bearing.

[0011] On the basis of the above technical solutions, further, during the hot rolling deformation process, the rolling speed is between (0.1~0.5)σC· / (σC - σF)·mm / s, where σC and σF are the elongation rates of the outer ring and inner ring materials respectively.

[0012] Since the stress-strain behaviors of the copper alloy and the bearing steel are quite different, when the rolling speed is too high, a speed difference will occur between the core roll and the driving roll, and it is extremely easy to cause damage to the interface; when the rolling speed is too low, the rolling time is long and the temperature drops relatively fast, but the forging temperature range is narrow, so the rolling speed must not be too low.

[0013] On the basis of the above technical solution, further, during the hot rolling deformation process, the rolling deformation amount is between (10 - 30)L / D·100%, where L is the depth of the laser cladding layer and D is the wall thickness of the bearing ring part.

[0014] Since the plastic deformation capabilities of copper alloy and bearing steel are quite different, when the rolling deformation amount is too large, a huge stress difference is generated on both sides of the interface, which is extremely likely to cause interface debonding and form interface crack defects; while when the rolling deformation amount is too small, the promotion effect of thermal deformation on interface healing is not good. Generally speaking, on the basis of ensuring that the interface does not debond, it is necessary to promote metallurgical bonding generated by interface thermal deformation as much as possible.

[0015] On the basis of the above technical solution, further, the steps of applying electromagnetic pulse include placing the bearing ring part in the working area of the electromagnetic pulse device, dividing the bearing ring part into 2n fan-shaped partitions, contacting the inner ring and the outer ring with electrodes according to the partitions respectively, and symmetrically loading the electrodes on the bearing ring part; where n is an integer greater than or equal to 4.

[0016] After setting at least 8 and an even number of partitions for the bearing ring part, the electrodes are symmetrically loaded on the bearing ring part, and the current path is controlled to be perpendicular to the heterogeneous material interface to ensure uniform treatment, avoid uneven overall deformation, and improve the electromagnetic pulse efficiency.

[0017] On the basis of the above technical solution, further, during the electromagnetic pulse process, the current magnitude is In the formula, H is the height of the bearing ring part, f is the pulse frequency, c p is the average specific heat capacity of the bearing ring part, d is the average density of the bearing ring part, ρ is the average resistivity of the bearing ring part, and σ is the average elongation of the bearing ring part.

[0018] During the electromagnetic pulse process, too large a current will cause the surface of the workpiece to be burned and damage the quality of the workpiece; too small a current will not achieve the effect of interface healing.

[0019] On the basis of the above technical solution, further, after the hot rolling deformation, heat the bearing ring part, and then perform the electromagnetic pulse. The heating temperature is between 0.8 - 0.9T m and the heating time is 1 - 3h, where the T m is the melting point of the outer ring material.

[0020] Heating the bearing ring part promotes the mutual diffusion of metal atoms on both sides of the interface and enhances metallurgical bonding.

[0021] On the basis of the above technical solution, further, the hot rolling temperature is the cross interval of the forging temperatures of the inner ring and the outer ring.

[0022] If the hot rolling temperature is not within this cross interval, it will lead to a large difference in the deformation resistance of the two materials, asynchronous thermal expansion coefficients of the two materials, uneven plastic deformation, and easily cause situations such as interface debonding and deformation warping, resulting in low interface bonding strength.

[0023] On the basis of the above technical solutions, further, the inner ring material is bearing steel, and the outer ring material is copper alloy.

[0024] On the basis of the above technical solutions, further, the surface roughness of the bearing ring is controlled between 100 and 1000 nm.

[0025] In a second aspect, the present invention provides a heterogeneous bearing ring manufactured by the above method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) In the present invention, through the multi-field synergistic action of light-thermal-mechanical-electricity, atomic-level interface bonding of heterogeneous bearing rings is achieved. While achieving the forming of bearing rings, a high-performance heterogeneous interface is obtained, significantly improving the bonding strength and performance of the heterogeneous interface of wind power sliding bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 Schematic diagram for electromagnetic pulse of heterogeneous bearing ring;

[0030] Figure 1 In which 1, electrode; 2, electrode; 3, outer ring; 4, inner ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] The present invention provides a method for multi-field construction and forming manufacturing of a heterogeneous bearing ring interface, including the following steps:

[0033] 1. Surface laser cladding to construct heterogeneous bearing rings

[0034] First, the surface of the bearing ring substrate is pretreated, including cleaning, degreasing and grinding to remove oil, oxide layer and impurities on the surface to ensure the cleanliness of the substrate surface.

[0035] Subsequently, the surface of the bearing ring is processed to control the surface roughness, waviness and texture direction to obtain a bearing ring with a certain surface texture. The surface roughness is controlled between 100 and 1000 nm, creating good conditions for laser cladding.

[0036] Secondly, select suitable copper alloy powder (such as tin bronze CuSn10, aluminum bronze CuAl10Fe3), the particle size is usually 50-150μm, to ensure fluidity and melting efficiency. Use high-power fiber laser, with coaxial powder feeding system, to ensure the powder is accurately delivered to the molten pool.

[0037] Inert gas (such as Ar) is required during the cladding process to protect the molten pool and prevent oxidation.

[0038] By controlling the laser power, scanning speed, spot diameter, and powder feeding rate parameters, multiple overlaps (overlap rate 30-50%) are used to cover the curved surface of the bearing ring to ensure that the copper alloy laser cladding layer is continuous and uniform.

[0039] 2. Overall thermal deformation promotes interface bonding

[0040] The laser clad bearing ring is placed in a heating furnace for heating. The heating temperature is usually set at the melting point of the copper alloy, T m 0.8-0.9 times of the original volume, and take it out after keeping warm for a certain period of time.

[0041] Subsequently, the bearing ring after heat preservation is transferred to a hot rolling ring machine, and the hot rolling temperature is the intersection range of the forging temperatures of the inner ring and the outer ring materials.

[0042] For example, the forging temperature of aluminum bronze alloy is 830-950℃, the forging temperature of 42CrMo bearing steel is 900-1200℃, and the final forging temperature is 900-950℃.

[0043] The driving roller is controlled to feed and the rolling deformation is controlled between (10-30)L / D·100%, where L is the depth of the laser cladding layer and D is the wall thickness of the bearing ring;

[0044] The rolling speed is controlled between (0.1 and 0.5)σC· / (σC-σF)·mm / s, wherein σC and σF are the elongations of the copper alloy and the bearing steel materials, respectively.

[0045] 3. Local electromagnetic pulses achieve atomic bonding

[0046] Place the hot-rolled bearing ring in the working area of the electromagnetic pulse device, such as Figure 1 As shown, divide the bearing ring into 2n sector partitions. Two electrodes (1) and (2) are in contact with the inner ring (4) and outer ring (3) of the bearing ring according to the partitions respectively, ensuring that the current passing direction is perpendicular to the interface direction, and the electrodes are symmetrically loaded on the bearing ring; where n is an integer greater than or equal to 4.

[0047] Among them, the electromagnetic pulse frequency is determined to be in the range of 5 - 50 Hz, and the current magnitude is set to I0, and where H is the height of the bearing ring, f is the pulse frequency, c p is the average specific heat capacity of the bearing ring, d is the average density of the bearing ring, ρ is the average resistivity of the bearing ring, and σ is the average elongation of the bearing ring.

[0048] After each partition of the bearing ring is processed, the electromagnetic pulse loading process for constructing the heterogeneous bearing ring is completed.

[0049] Example 1

[0050] This example provides a method for forming and manufacturing a heterogeneous bearing ring interface with multiple fields. Using 42CrMo bearing steel as the matrix, laser cladding of copper alloy powder is carried out, which specifically includes the following steps:

[0051] 1. Surface laser cladding to construct a heterogeneous bearing ring

[0052] Perform pretreatment on the surface of the 42CrMo bearing steel matrix: First, place the matrix in an alkaline cleaning agent and clean it in an ultrasonic cleaner for 15 minutes to remove surface oil; then carefully wipe it twice with a degreaser to ensure no oil residue remains and the surface is clean.

[0053] Subsequently, surface grinding is used to form surface texture, and the surface roughness is controlled at 500 nm to create good conditions for laser cladding.

[0054] Select tin bronze CuSn10 powder with a particle size of 100 μm, and use a high-power fiber laser in combination with a coaxial powder feeding system. Set the laser power to 2200 W, the scanning speed to 7 mm / s, the spot diameter to 3.5 mm, the powder feeding rate to 15 g / min, use argon as the shielding gas to protect the molten pool from oxidation, and use a multi-pass overlapping (overlapping rate 40%) method to cover the curved surface of the bearing ring, and the cladding depth is determined to be 3 mm.

[0055] 2. Overall thermal deformation to promote interface bonding

[0056] Put the laser-cladded bearing ring into a heating furnace, heat it to 960 °C (about 0.85 times the melting point of the copper alloy), hold it for 2.5 h and then take it out, and transfer it to a hot rolling ring machine.

[0057] It is known that the depth L of the laser cladding layer is 3 mm, the wall thickness D of the bearing ring is 200 mm, and the rolling deformation is controlled within (10 - 30)L / D·100%, taking 20L / D·100%, that is, 30%;

[0058] It is known that the elongation rate σC of the tin bronze alloy is 35%, and the elongation rate σF of the 42CrMo bearing steel material is 12%. The rolling speed is controlled within (0.1 - 0.5)σC / (σC - σF)·mm / s. Calculate (0.1 - 0.5)×35% / (35% - 12%)·mm / s, and take 0.2×35% / (35% - 12%)·mm / s = 0.3 mm / s.

[0059] After hot rolling, the thickness uniformity and surface quality of the workpiece are detected again.

[0060] 3. Local electromagnetic pulse realizes atomic bonding

[0061] Place the bearing ring after hot rolling deformation in the working area of the electromagnetic pulse device. Divide the bearing ring blank into 16 zones (n = 8), as Figure 1 shown. Two electrodes (1) and (2) are respectively in contact with the inner ring (4) and the outer ring (3) of the bearing ring, ensuring that the current passing direction is perpendicular to the interface direction.

[0062] Select the frequency of the electromagnetic pulse to be 20 Hz. It is known that the height H of the bearing ring is 150 mm, the inner diameter is 700 mm, and the outer diameter is 900 mm. After measurement, the average specific heat capacity C p = 498.5 J / (kg·K), the average density d = 7872.3 kg / m 3 , the average elongation rate σ = 23.5%, and the average resistivity of the tin bronze alloy and the bearing steel material is 2×10 -7 Ω·m. Calculate Set the input current parameters according to the calculation results, start the electromagnetic pulse device, and process each zone of the rolled bearing ring in turn to complete the electromagnetic pulse loading process.

[0063] Comparative Example 1

[0064] This comparative example is basically the same as Example 1, and the difference is that: in this comparative example, only step 1 of surface laser cladding to construct a heterogeneous bearing ring is performed, and steps 2 of overall thermal deformation to promote interface bonding and 3 of local electromagnetic pulse to realize atomic bonding are omitted.

[0065] Comparative Example 2

[0066] This comparative example is basically the same as Example 1, except that: in this comparative example, only Step 1 of surface laser cladding to construct a heterogeneous bearing ring part and Step 2 of overall thermal deformation to promote interface bonding are carried out, and Step 3 of local electromagnetic pulse to achieve atomic bonding is omitted.

[0067] Comparative Example 3

[0068] This comparative example is basically the same as Example 1, except that: in this comparative example, only Step 1 of surface laser cladding to construct a heterogeneous bearing ring part and Step 3 of local electromagnetic pulse to achieve atomic bonding are carried out, and Step 2 of overall thermal deformation to promote interface bonding is omitted.

[0069] Performance testing:

[0070] Wire cutting sampling is carried out at the interface of the bearing ring parts prepared in the above examples and comparative examples. The interface position is at the center of the sampled specimen, and the interface is perpendicular to the tensile direction. The interface bonding strength is tested by a tensile testing machine, and the obtained tensile strength is used to evaluate the interface bonding strength.

[0071] The tensile strength at the bonding interface of the bearing ring part prepared in Example 1 reaches 423 MPa, which is significantly higher than the tensile strength of as-cast tin bronze CuSn10.

[0072] The tensile strength at the bonding interface of the bearing ring part prepared in Comparative Example 1 reaches 238 MPa.

[0073] The tensile strength at the bonding interface of the bearing ring part prepared in Comparative Example 2 reaches 355 MPa.

[0074] The tensile strength at the bonding interface of the bearing ring part prepared in Comparative Example 3 reaches 302 MPa.

[0075] By comparing the results of Example 1 and Comparative Example 1, it shows that not carrying out hot rolling and electromagnetic pulse on the bearing ring part will lead to a decrease in the tensile strength at the bonding interface. The possible reason is that only laser cladding is carried out. Due to the large difference in thermophysical properties at the heterogeneous interface, defects such as cracks are likely to remain at the interface, and there may also be undiffused impurities or microvoids, resulting in a lower bonding strength.

[0076] By comparing the results of Example 1 and Comparative Example 2, it shows that not carrying out electromagnetic pulse on the bearing ring part will lead to a decrease in the tensile strength at the bonding interface. The possible reason is that electromagnetic pulse can trigger electron migration and lattice vibration at the copper alloy / bearing steel matrix interface, promote interface atomic bonding, and achieve high-density interface atomic-level bonding. When the electromagnetic pulse is lacking, the atomic diffusion rate at the heterogeneous interface decreases, and longer rolling time or larger deformation amount is required to reach the same bonding strength. However, large deformation amount and long-time high-temperature state are likely to cause abnormal grain growth, reducing the strength and toughness of the material.

[0077] By comparing the results of Example 1 and Comparative Example 3, it is shown that the lack of hot rolling deformation of the bearing ring parts leads to a decrease in the tensile strength at the bonding interface. The possible reason is that the high-temperature plastic deformation without hot rolling promotes the fitting of the interface morphology, resulting in a poor degree of mechanical interlocking, limited improvement in metallurgical bonding, and the interface strength still depending on the quality of laser cladding. The interface bonding is weak, and the material has not undergone forging deformation, so its deformation performance is not optimized.

[0078] This shows that the multi-field construction forming manufacturing method for the interface of heterogeneous bearing ring parts proposed by the present invention can obtain an interface with high-strength metallurgical bonding, and the constructed copper alloy surface layer has excellent corrosion resistance and wear resistance, thus realizing the high-performance construction forming of heterogeneous materials for wind power sliding bearings.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a heterogeneous bearing ring interface by multi-field construction, characterized in that: The outer ring material is laser clad on the inner ring surface of the bearing ring, and then hot-rolled and deformed. The bearing ring is divided into zones, and electromagnetic pulses are applied to the bearing ring according to the zones to obtain a heterogeneous bearing ring, wherein the inner ring and the outer ring are made of two different materials.

2. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: During the hot rolling deformation process, the rolling speed is between (0.1 and 0.5)σC· / (σC-σF)·mm / s, wherein σC and σF are the elongation of the outer ring and inner ring materials respectively.

3. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: During the hot rolling deformation process, the rolling deformation amount is between (10-30)L / D·100%, wherein L is the depth of the laser cladding layer, and D is the wall thickness of the bearing ring.

4. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: The step of applying electromagnetic pulses includes placing the bearing ring in the working area of ​​the electromagnetic pulse device, setting the bearing ring into 2n sector-shaped partitions, and the electrodes contact the inner ring and the outer ring respectively according to the partitions, and the electrodes are symmetrically loaded on the bearing ring; wherein n is an integer greater than or equal to 4.

5. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: During the electromagnetic pulse process, the current magnitude is Where H is the height of the bearing ring, f is the pulse frequency, c p is the average specific heat capacity of the bearing ring, d is the average density of the bearing ring, ρ is the average resistivity of the bearing ring, and σ is the average elongation of the bearing ring.

6. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: After the hot rolling deformation, the bearing ring is heated, and then the electromagnetic pulse is performed, and the heating temperature is 0.8-0.9T m The heating time is 1 to 3 hours, wherein the T m is the melting point of the outer ring material.

7. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: The hot rolling temperature is an intersection range of the forging temperatures of the inner ring and the outer ring.

8. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: The inner ring material is bearing steel, and the outer ring material is copper alloy.

9. The method for manufacturing a heterogeneous bearing ring interface by multi-field construction according to claim 1, characterized in that: The surface roughness of the bearing ring is controlled between 100 and 1000 nm.

10. A heterogeneous bearing ring manufactured by the heterogeneous bearing ring interface multi-field construction forming manufacturing method as described in any one of claims 1 to 9.

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