A multi-field construction forming manufacturing method for a heterogeneous bearing ring piece interface

Abstract

The application discloses a kind of heterogeneous bearing ring piece interface multi-field construction forming manufacturing method, which is by laser cladding outer ring material to the inner ring surface of bearing ring piece, then heat rolling deformation is carried out, the bearing ring piece is set partition, electrode is respectively contacted with the inner ring and outer ring according to partition and electromagnetic pulse is applied, and heterogeneous bearing ring piece is prepared, wherein the inner ring and outer ring are two different materials.The application realizes atomic level interface bonding of heterogeneous bearing ring piece by light-heat-force-electricity multi-field synergistic effect, realizes the forming of heterogeneous bearing ring piece, and obtains high-performance heterogeneous interface at the same time, which significantly improves the bonding strength and performance of heterogeneous interface of wind power sliding bearing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bearing manufacturing, and particularly relates to a multi-field construction forming manufacturing method for a heterogeneous bearing ring piece interface. BACKGROUND

[0002] Wind power generation is an important way for China to achieve the "double carbon" goal, and offshore wind power has become a key field for countries to compete. Bearings are the core components of wind turbine generators, directly determining the service performance and power generation efficiency of wind turbine generators. With the upgrading of large megawatt wind turbines, the load of bearings increases exponentially, and needs to face extreme working conditions such as alternating heavy load, high humidity, and salt spray corrosion, which puts extreme demands on the wear resistance and corrosion resistance of bearings. Traditional wind power main bearings often use rolling bearing structures, while compared with rolling bearings, sliding bearing structures are simpler and have stronger load capacity, and are more suitable for complex offshore working conditions. "Replacing rolling with sliding" has become a frontier direction for the development of future wind power bearings.

[0003] Due to the excellent corrosion resistance, wear resistance and heat conduction performance characteristics of copper alloy, laser cladding copper alloy on the surface of the bearing becomes an effective way to solve the wear resistance and corrosion resistance of the wind power main bearing. The surface cladding of copper alloy improves the corrosion resistance and wear resistance, and the core still retains the bearing steel material to ensure the load capacity of the bearing bush. However, the surface layer of copper alloy formed by this process has a cast structure, and the loose defects lead to insufficient material density. In addition, the thermal physical parameter gradient of copper / steel heterogeneous materials changes sharply, which leads to poor interface bonding, seriously restricting the engineering application of sliding bearings. Therefore, for the front direction of wind power sliding bearings, the existing heterogeneous material construction methods have the problems of poor organization state and poor interface bonding. How to realize the atomic level bonding of copper alloy / bearing heterogeneous ring piece interface is the core problem of developing a new generation of wind power sliding bearings. SUMMARY

[0004] Therefore, the application provides a multi-field construction forming manufacturing method for a heterogeneous bearing ring piece interface. Copper alloy is laser cladded on the surface of a bearing steel substrate, heat rolling is used to promote atomic diffusion and metallurgical bonding between the copper alloy and the bearing steel substrate, electromagnetic pulses are further used to promote atomic bonding and lattice matching between the copper alloy and the bearing substrate, and finally atomic level bonding of the high-density copper alloy / bearing steel heterogeneous interface is realized. The new method is expected to solve the problem of heterogeneous interface bonding of high wear-resistant and corrosion-resistant sliding bearings.

[0005] The technical scheme of the application is implemented as follows:

[0006] In a first aspect, the application provides a method for constructing a heterogeneous bearing ring interface by using multiple fields, which comprises the following steps: laser cladding an outer ring material on an inner ring surface of a bearing ring, then performing hot rolling deformation on the bearing ring, setting a partition on the bearing ring, and applying electromagnetic pulses to the bearing ring according to the partition, thereby obtaining 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 fully wetted during the solid-liquid combination of laser cladding, and the interface morphology is better fitted.

[0008] The laser cladding is performed in a protective atmosphere to avoid the contact between the interface and air to form harmful oxides. By controlling the laser power, scanning speed, spot diameter and powder feeding rate, part of the bearing steel on the surface of the bearing ring is melted, the laser cladding copper alloy is more fitted to the curved surface of the bearing ring, and part of the copper alloy and the bearing steel are metallurgically combined.

[0009] During the hot rolling deformation, the heat and force make the laser cladding layer change from a cast structure to a forged structure, thereby improving the performance of the laser cladding layer. During the hot rolling deformation, the interface between the copper alloy layer and the bearing steel substrate produces coordinated plastic deformation, thereby further increasing the interface contact area and mechanical interlocking. Meanwhile, during the high-temperature deformation, the copper alloy layer and the bearing steel substrate are fully softened at high temperature, thereby reducing the energy barrier of atomic diffusion and promoting the thermal motion and mutual diffusion of atoms.

[0010] By loading electromagnetic pulses, the current flows through the interface region to form a local high-energy field in the interface region, which induces electron migration and lattice vibration at the copper alloy / bearing steel substrate interface, promotes the formation of atomic bonding and the matching adjustment of the crystal lattice at the interface, eliminates possible small gaps and mismatched areas at the interface, and realizes atomic-level combination 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 solution, further, during the hot rolling deformation, the rolling speed is between (0.1-0.5)σC· / (σC-σF)·mm / s, wherein σC and σF are the elongation rates of the outer ring and inner ring materials, respectively.

[0012] Because the stress and strain behaviors of copper alloy and bearing steel are quite different, when the rolling speed is too large, a speed difference will occur between the core roller and the driving roller, which will easily damage the interface. When the rolling speed is too small, the rolling time is long, the temperature drops quickly, but the forging temperature interval is narrow, and the rolling speed must be controlled not to be too small.

[0013] On the basis of the above technical solutions, further, in the hot rolling deformation process, the rolling deformation is between (10-30) L / D*100%, wherein L is the laser cladding layer depth, and D is the bearing ring wall thickness.

[0014] Because the plastic deformation ability of copper alloy and bearing steel is greatly different, when the rolling deformation is too large, a large stress difference is generated on both sides of the interface, which is extremely easy to cause interface debonding and form interface crack defects; and when the rolling deformation is too small, the promotion effect of thermal deformation on interface healing is not good, and in general, on the basis of ensuring that the interface does not debond, the metallurgical bonding generated under the interface thermal deformation is promoted as much as possible.

[0015] On the basis of the above technical solutions, further, the step of applying the electromagnetic pulse includes placing the bearing ring in the working area of the electromagnetic pulse device, setting 2n sector partitions of the bearing ring, and contacting the electrodes with the inner ring and the outer ring according to the partitions, wherein the electrodes are symmetrically loaded on the bearing ring; wherein n is an integer greater than or equal to 4.

[0016] After the bearing ring is provided with at least 8 and even number of partitions, the electrodes are symmetrically loaded on the bearing ring, the current path is controlled to be perpendicular to the heterogeneous material interface, uniform treatment is ensured, overall deformation is avoided, and the electromagnetic pulse efficiency is improved.

[0017] On the basis of the above technical solutions, further, in the electromagnetic pulse process, the current size is In the formula, 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, p is the average resistivity of the bearing ring, and sigma is the average elongation of the bearing ring.

[0018] In the electromagnetic pulse process, too large current will cause surface burn of the workpiece and damage the quality of the workpiece; and too small current cannot achieve the effect of interface healing.

[0019] On the basis of the above technical solutions, further, after the hot rolling deformation, the bearing ring is heated, and then the electromagnetic pulse is performed, the heating temperature is 0.8-0.9T m , and the heating time is 1-3h, wherein T m is the melting point of the outer ring material.

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

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

[0022] If the temperature of hot rolling is not in the intersection interval, the difference of deformation resistance of the two materials is large, the thermal expansion coefficients of the two materials are not synchronized, the plastic deformation is uneven, and the interface debonding, deformation warping and the like are easily caused, and the interface bonding strength is low.

[0023] Further, the inner ring material is bearing steel, and the outer ring material is copper alloy.

[0024] Further, the surface roughness of the bearing ring is controlled between 100-1000nm.

[0025] In the second aspect, the application provides a heterogeneous bearing ring prepared by the above method.

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

[0027] (1) In the application, the atomic-level interface bonding of the heterogeneous bearing ring is realized through the synergistic effect of light-heat-force-electricity multi-field, the high-performance heterogeneous interface is obtained while the bearing ring is formed, and the bonding strength and performance of the heterogeneous interface of the wind power sliding bearing are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0029] Figure 1 It is a schematic diagram of the electromagnetic pulse for the heterogeneous bearing ring;

[0030] Figure 1 1, electrode, 2, electrode, 3, outer ring, 4, inner ring. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments of the application. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0032] The application provides a heterogeneous bearing ring interface multi-field construction forming manufacturing method, which comprises the following steps:

[0033] 1, surface laser cladding construction of the heterogeneous bearing ring

[0034] Firstly, the bearing ring base surface is pretreated, including cleaning, degreasing and polishing, etc., to remove the oil stains, oxide layer and impurities on the surface, and ensure the cleanliness of the base surface.

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

[0036] Thirdly, suitable copper alloy powder (such as tin bronze CuSn10, aluminum bronze CuAl10Fe3) is selected, and the particle size is usually 50-150 μm, which ensures the fluidity and melting efficiency. A high-power fiber laser is used, and a coaxial powder feeding system is used to ensure accurate powder delivery to the molten pool.

[0037] In the cladding process, inert gas (such as Ar) is needed to protect the molten pool to prevent oxidation.

[0038] By controlling the parameters of laser power, scanning speed, spot diameter and powder feeding rate, the bearing ring curved surface is covered by multiple overlapping (overlapping rate 30-50%) to ensure the continuity and uniformity of the copper alloy laser cladding layer.

[0039] 2. Overall thermal deformation promotes interface bonding

[0040] The bearing ring after laser cladding is placed in a heating furnace for heating, and the heating temperature is usually set between 0.8-0.9 times of the melting point T m of the copper alloy, and then taken out after a certain holding time.

[0041] Subsequently, the bearing ring after holding is transferred to a hot rolling ring machine, and the hot rolling temperature is the intersection interval of the forging temperature of the inner and outer rings of the two materials.

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

[0043] The driving roller feeding motion is controlled, and the rolling deformation is controlled between (10-30) L / D·100%, wherein L is the laser cladding layer depth, and D is the bearing ring wall thickness.

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

[0045] 3. Local electromagnetic pulse realizes atomic bonding

[0046] The bearing ring after hot rolling deformation is placed in the working area of the electromagnetic pulse device, as shown in Figure 1 Fig. 1, the bearing ring is divided into 2n sectors, two electrodes (1) and (2) are in contact with the inner ring (4) and the outer ring (3) of the bearing ring respectively according to the sectors, the current passing direction is perpendicular to the interface direction, and the electrodes are symmetrically loaded on the bearing ring; wherein n is an integer greater than or equal to 4.

[0047] The electromagnetic pulse frequency is determined to be in the range of 5-50 Hz, the current size 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, p is the average resistivity of the bearing ring, and s is the average elongation of the bearing ring.

[0048] After the treatment of each sector of the bearing ring is completed, the electromagnetic pulse loading process of the heterogeneous bearing ring is completed.

[0049] Example 1

[0050] The embodiment provides a heterogeneous bearing ring interface multi-field construction forming manufacturing method, taking 42CrMo bearing steel as a matrix, and laser cladding copper alloy powder, and specifically includes the following steps:

[0051] 1. Surface laser cladding construction of heterogeneous bearing ring

[0052] The surface of the 42CrMo bearing steel matrix is pretreated: first, the matrix is placed in an alkaline cleaning agent and cleaned in an ultrasonic cleaner for 15 minutes to remove surface oil; then, the matrix is carefully wiped twice with a degreasing agent to ensure that there is no oil residue and that the surface is clean.

[0053] Subsequently, surface grinding is performed to form surface texture, and the surface roughness is controlled to be 500 nm, thereby creating good conditions for laser cladding.

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

[0055] 2. Promote interface bonding by overall thermal deformation

[0056] The bearing ring after laser cladding is placed in a heating furnace and heated to 960℃ (about 0.85 times the melting point of copper alloy), and then taken out after 2.5h of heat preservation and transferred to a hot rolling ring machine.

[0057] Known laser cladding layer depth L = 3mm, bearing ring wall thickness D = 200mm, rolling deformation is controlled in (10-30) L / D-100%, taking 20L / D-100%, namely 30%;

[0058] Known tin bronze alloy elongation σC=35%, 42CrMo bearing steel material elongation σF=12%, rolling speed is controlled in (0.1-0.5) σC / (σC-σF)-mm / s, calculating (0.1-0.5) x 35% / (35%-12%)·mm / s, taking 0.2 x 35% / (35%-12%)·mm / s = 0.3mm / s.

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

[0060] 3. Local electromagnetic pulse realizes atomic bonding

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

[0062] The frequency of the electromagnetic pulse is selected as 20Hz, and the bearing ring height H = 150mm, the inner diameter is 700mm, and the outer diameter is 900mm, the average specific heat capacity C p = 498.5J / (kg·K), the average density d = 7872.3kg / m 3 , the average elongation σ = 23.5%, and the average resistivity of tin bronze alloy and bearing steel material is 2 x 10 -7 Ω·m, calculating According to the calculation result, the input current parameter is set, the electromagnetic pulse device is started, and each partition of the rolled bearing ring is processed in turn, and the electromagnetic pulse loading process is completed.

[0063] Comparative Example 1

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

[0065] Comparative Example 2

[0066] The comparative example is basically the same as example 1, the difference is that the comparative example only does step 1 surface laser cladding to build a heterogeneous bearing ring and step 3 local electromagnetic pulse to realize atomic bonding, and step 2 overall thermal deformation to promote interface bonding is omitted.

[0067] Comparative example 3

[0068] The comparative example is basically the same as example 1, the difference is that the comparative example only does step 1 surface laser cladding to build a heterogeneous bearing ring and step 3 local electromagnetic pulse to realize atomic bonding, and step 2 overall thermal deformation to promote interface bonding is omitted.

[0069] Performance test:

[0070] The interface of the bearing ring prepared in the above examples and comparative examples is sampled by wire cutting, the interface position is in the center of the sample, the interface is perpendicular to the stretching direction, and the interface bonding strength is tested by using a tensile testing machine, and the tensile strength obtained is used to evaluate the interface bonding strength.

[0071] The tensile strength of the bonding interface of the bearing ring 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 of the bonding interface of the bearing ring prepared in comparative example 1 reaches 238 MPa.

[0073] The tensile strength of the bonding interface of the bearing ring prepared in comparative example 2 reaches 355 MPa.

[0074] The tensile strength of the bonding interface of the bearing ring prepared in comparative example 3 reaches 302 MPa.

[0075] By comparing the results of example 1 and comparative example 1, it is shown that not performing hot rolling and electromagnetic pulse on the bearing ring will cause the tensile strength of the bonding interface to decrease, and the possible reason is that only laser cladding is performed, the heterogeneous interface is prone to defects such as residual cracks due to large differences in thermal physical properties, and there may also be insufficient diffusion of impurities or micropores, resulting in low bonding strength.

[0076] By comparing the results of example 1 and comparative example 2, it is shown that not performing electromagnetic pulse on the bearing ring will cause the tensile strength of the bonding interface to decrease, and the possible reason is that electromagnetic pulse can induce electron migration and lattice vibration at the copper alloy / bearing steel interface, promote interface atomic bonding, and realize high-density interface atomic-level bonding. Without electromagnetic pulse, the atomic diffusion rate of the heterogeneous interface decreases, and a longer time or larger deformation amount is required to achieve the same bonding strength, but large deformation amount and long time high temperature state is prone to abnormal grain growth, which reduces the strength and toughness of the material.

[0077] By comparing the results of Example 1 and Comparative Example 3, it is shown that the tensile strength at the bonding interface is reduced due to the fact that the bearing ring is not subjected to hot rolling deformation, and the possible reason is that the high-temperature plastic deformation not subjected to hot rolling promotes the interface morphology to fit, the mechanical embedding degree is poor, the improvement of metallurgical bonding is limited, the interface strength still depends on the quality of laser cladding, the interface bonding is weak, and the material is not subjected to forging deformation, and the performance is not optimized.

[0078] Therefore, it is shown that the interface multi-field construction forming manufacturing method of the heterogeneous bearing ring can obtain an interface with high-strength metallurgical bonding, and the copper alloy surface layer constructed has excellent corrosion resistance and wear resistance, thereby realizing the high-performance construction forming of the heterogeneous material of the wind power sliding bearing.

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

Claims

1. A hetero-axial bearing ring piece interface multi-field constructed forming manufacturing method, characterized in that, The method comprises the following steps: laser cladding outer ring material on the inner ring surface of a bearing ring, then performing hot rolling deformation, setting partitions for the bearing ring, and respectively applying electromagnetic pulses to the bearing ring according to the partitions to obtain a heterogeneous bearing ring, wherein the inner ring and the outer ring are made of two different materials. During the hot rolling deformation, the rolling speed is between (0.1-0.5)σC / (σC-σF)·mm / s, wherein σC and σF are the elongation rates of the outer ring material and the inner ring material, respectively. During the hot rolling deformation, the rolling deformation amount is between (1-3)L / D·100%, wherein L is the laser cladding layer depth, and D is the wall thickness of the bearing ring. The step of applying electromagnetic pulses comprises the following steps: placing the bearing ring in the working area of an electromagnetic pulse device, setting 2n sector partitions for the bearing ring, and respectively contacting the inner ring and the outer ring with electrodes according to the partitions, wherein the electrodes are symmetrically loaded on the bearing ring; n is an integer greater than or equal to 4. During the electromagnetic pulse process, the current size is , in the formula, H is the bearing ring height, f is the pulse frequency, is the average specific heat capacity of the bearing ring, d is the average density of the bearing ring, is the average resistivity of the bearing ring, and σ is the average elongation of the bearing ring.

2. The hetero-bearing ring piece interface multi-field constructed shaping manufacturing method of claim 1, wherein, After the hot rolling deformation, the bearing ring is heated to a temperature of 0.8-0.9 T m , and the electromagnetic pulse is applied, wherein the heating time is 1-3 h, and T m is the melting point of the outer ring material.

3. The hetero-bearing ring piece interface multi-field constructed shaping manufacturing method of claim 1, wherein, The temperature of the hot rolling is the intersection interval of the forging temperatures of the inner ring and the outer ring.

4. The hetero-bearing ring piece interface multi-field constructed shaping manufacturing method of claim 1, wherein, The inner ring material is bearing steel, and the outer ring material is copper alloy.

5. The hetero-bearing ring piece interface multi-field constructed shaping manufacturing method of claim 1, wherein, The surface roughness of the bearing ring is controlled to be between 100-1000 nm.

6. The heterogeneous bearing ring obtained by the interface multi-field construction forming manufacturing method of any one of claims 1-5.

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