1. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling is characterized by comprising the following steps of:

s1, cleaning the bearing ring substrate;

s2, preparing a bearing ring coating:

s21, installation: mounting a sputtering target needing magnetron sputtering on a direct current cathode, placing a matrix in a sample table, and fixing the distance between the sputtering target and the matrix to be 150mm, wherein the matrix is positioned at the anode;

s22, intermediate-frequency bias flushing: the vacuum chamber was evacuated to 1x10^-3Pa, heating the substrate to 450 ℃, introducing Ar into the vacuum chamber, controlling the flow of Ar to be 250sccm and the working pressure to be 2.5 Pa; starting an intermediate frequency power supply, setting the voltage to be 1000V, and cleaning the surface of the bearing ring substrate for 15 min;

s23, sputtering a priming layer: regulating the flow of Ar to be 100sccm, setting the working air pressure to be 1.0Pa, setting the voltage of a medium-frequency bias power supply to be 800V and the duty ratio to be 50%, simultaneously starting a sputtering electrode of the sputtering target, setting the current to be 30A and the sputtering time to be 8min, and sputtering a priming layer on the substrate;

s24, sputtering the bulk layer: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 10sccm and N₂The flow rate of the gas is 400sccm, and the working air pressure is 1.0 Pa; setting the voltage of a medium-frequency bias power supply to be 200V and the duty ratio to be 50%, setting the current of a sputtering power supply to be 80A and the sputtering time to be 30min, and sputtering a main body layer on the priming layer;

s3, preparing a magnetron sputtering coating: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 50sccm and N₂The flow rate of the sputtering target is 50sccm, the working air pressure is 0.6Pa, the direct-current sputtering power is set to be 150W, and the sputtering time is set to be 30min, so that a magnetron sputtering coating is formed;

s4, ultrasonic rolling reinforcement:

s41, pressing the ultrasonic rolling device on the surface of the bearing ring by a pre-pressing depth to apply a back pressure to the bearing ring;

s42, rolling the rolling ball tool head of the ultrasonic rolling device on the surface of the bearing ring, and driving the ultrasonic rolling device to do ultrasonic frequency mechanical vibration through input current to finish ultrasonic rolling reinforcement.

2. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling composite of claim 1, wherein after the step S42 is completed, the steps S23, S24, S3 and S4 are repeated to prepare a double-layer coating.

3. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling composite of the claim 1, wherein after the step S42 is completed, the steps S23, S24, S3 and S4 are repeated for two times to prepare the multilayer coating.

4. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling composite of claim 2 or 3, wherein the step S4 further comprises a controller for controlling the ultrasonic rolling device, and the controller adjusts at least one of the pre-pressing depth, the back pressure and the input current based on the desired residual compressive stress and the real-time rolling force.

5. The method for compound strengthening of the surface of the bearing ring based on magnetron sputtering and ultrasonic rolling according to claim 4, wherein the ultrasonic rolling device comprises an ultrasonic generator, a bracket shell, a spring, an energy converter, an amplitude transformer and a rolling ball tool head, the bracket shell is connected to a tool rest of a machine tool through a clamping mechanism, the spring, the energy converter and the amplitude transformer are sequentially connected and arranged inside the bracket shell, the upper end of the amplitude transformer extends out of the bracket shell and then is connected with the rolling ball tool head, the lower end of the spring is fixed with the upper bottom surface of the bracket shell, and the energy converter receives an ultrasonic signal sent by the ultrasonic generator and transmits ultrasonic frequency mechanical vibration to the amplitude transformer.

6. The method for strengthening the surface of the bearing ring based on the combination of magnetron sputtering and ultrasonic rolling according to claim 1, wherein the sputtering target is selected from any one of Cu, C, Cr, Ti, Ni, Al, Si and Zr or a metal alloy consisting of any two or more of the metal materials.

7. The method for strengthening the surface of the bearing ring based on the combination of magnetron sputtering and ultrasonic rolling according to claim 4, wherein the sputtering target is a TiSi target.

8. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling composite of the claim 4, wherein the sputtering target is an aluminum copper target with a purity of 99.9% or a carbon target with a purity of 99.9%.

9. The method for strengthening the surface of the bearing ring based on the combination of magnetron sputtering and ultrasonic rolling according to claim 1, wherein the surface roughness Ra of the sputtering target is less than 1mm, the thickness of the sputtering target is 50mm or less, and the sputtering target is a non-magnetic material particle dispersion type sputtering target.

10. The method for strengthening the surface of the bearing ring based on the magnetron sputtering and ultrasonic rolling composite of claim 1, wherein the base body of the bearing ring is made of 42CrMo metal.

Background

The bearing is often used under the severe working conditions of variable load, variable speed, high DN value, intermittent service, oil cut and the like, and a coating is often sprayed on the bearing and a bearing sleeve ring in order to prolong the service life of the bearing and improve the working reliability of the bearing. At present, as mechanical parts in various industries are developing toward long life and high stability, the performance requirements of the coating layer are increasing.

In recent years, new technologies such as unbalanced magnetic field, multi-target magnetic field coupling, twin magnetron targets, pulse sputtering, medium-frequency alternating-current sputtering power supply and the like appear and develop, so that the magnetron sputtering technology is widely applied to the preparation of coatings of key matching parts.

On the basis of the magnetron sputtering technology, the bearing ring coating suitable for extreme working conditions is researched and prepared so as to achieve excellent performances of ultralow friction factor, low wear rate, high bearing capacity and the like of the coating, and the method has very important significance.

Disclosure of Invention

The invention aims to provide a method for strengthening the surface of a bearing ring based on magnetron sputtering and ultrasonic rolling, which can improve the bonding strength between a coating and a substrate and obviously enhance the uniformity and compactness of the coating.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a method for strengthening the surface of a bearing ring based on magnetron sputtering and ultrasonic rolling composite comprises the following steps:

s1, cleaning the bearing ring substrate;

s2, preparing a bearing ring coating:

s21, installation: mounting a sputtering target of magnetron sputtering on a direct current cathode, placing a matrix in a sample table, and fixing the distance between the sputtering target and the matrix to be 150mm, wherein the matrix is positioned at the anode;

s22, intermediate-frequency bias flushing: the vacuum chamber was evacuated to 1x10^-3Pa, heating the substrate to 450 ℃, introducing Ar into the vacuum chamber, controlling the flow of Ar to be 250sccm and the working pressure to be 2.5 Pa; starting an intermediate frequency power supply, setting the voltage to be 1000V, and cleaning the surface of the bearing ring substrate for 15 min;

s23, sputtering a priming layer: regulating the flow of Ar to be 100sccm, setting the working air pressure to be 1.0Pa, setting the voltage of a medium-frequency bias power supply to be 800V and the duty ratio to be 50%, simultaneously starting a sputtering electrode of the sputtering target, setting the current to be 30A and the sputtering time to be 8min, and sputtering a priming layer on the substrate;

s24, sputtering the bulk layer: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 10sccm and N₂The flow rate of the gas is 400sccm, and the working air pressure is 1.0 Pa; setting the voltage of a medium-frequency bias power supply to be 200V and the duty ratio to be 50%, setting the current of a sputtering power supply to be 80A and the sputtering time to be 30min, and sputtering a main body layer on the priming layer;

s3, preparing a magnetron sputtering coating: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 50sccm and N₂The flow rate of the sputtering target is 50sccm, the working air pressure is 0.6Pa, the direct-current sputtering power is set to be 150W, and the sputtering time is set to be 30min, so that a magnetron sputtering coating is formed;

s4, ultrasonic rolling reinforcement:

s41, pressing the ultrasonic rolling device on the surface of the bearing ring by a pre-pressing depth to apply a back pressure to the bearing ring;

s42, rolling the rolling ball tool head of the ultrasonic rolling device on the surface of the bearing ring, and driving the ultrasonic rolling device to do ultrasonic frequency mechanical vibration through input current to finish ultrasonic rolling reinforcement.

Preferably, after step S42 is completed, steps S23, S24, S3 and S4 are repeated again to prepare a double-layer coating.

Preferably, after step S42 is completed, steps S23, S24, S3 and S4 are repeated two more times to prepare a multilayer coating.

Further, step S4 includes a controller for controlling the ultrasonic rolling device, wherein the controller adjusts at least one of the pre-compression depth, the back pressure and the input current based on the desired residual compressive stress and the real-time rolling force.

Furthermore, supersound rolling press device includes ultrasonic generrator, support shell, spring, transducer, amplitude transformer and spin tool head, the support shell passes through fixture and connects on the lathe knife rest, spring, transducer and amplitude transformer connect gradually and set up in the inside of support shell, amplitude transformer upper end is connected with spin tool head after stretching out the support shell, the spring lower extreme is fixed with the last bottom surface of support shell, the ultrasonic signal that ultrasonic generrator sent is received to the transducer to transmit ultrasonic frequency mechanical oscillation to amplitude transformer.

Further, the sputtering target is selected from any one metal material of Cu, C, Cr, Ti, Ni, Al, Si and Zr or a metal alloy consisting of any two or more metal materials.

Still further, the sputtering target is a TiSi target.

Further, the sputtering target is an aluminum copper target with a purity of 99.9% or a 99.9% carbon target.

Further, the surface roughness Ra of the sputtering target is less than 1mm, the thickness of the sputtering target is 50mm or less, and the sputtering target is a nonmagnetic material particle dispersion type sputtering target.

Furthermore, the bearing ring base body is made of 42CrMo metal.

The beneficial effects brought by the invention are as follows:

1. the invention firstly adopts the magnetron sputtering technology to prepare the surface coating, and then further strengthens the coating and the matrix through the ultrasonic rolling technology, thereby effectively improving the coating bonding strength on the surface of the bearing ring.

2. The invention prepares the multilayer coating by repeating the steps of magnetron sputtering and ultrasonic rolling, and each layer of sputtered coating is strengthened by ultrasonic rolling, so that the surface of the bearing ring generates violent microscopic plastic deformation, the bonding strength between the coating on the surface of the bearing ring and the matrix is higher, and the uniformity and the compactness of the coating are obviously enhanced.

3. The invention adopts a processing mode combining static load and ultrasonic dynamic load to carry out high-frequency vibration impact on the surface layer of the bearing ring, fully exerts the advantages of magnetron sputtering and ultrasonic rolling, obviously enhances the uniformity and the compactness of the prepared film coating compared with the film coating which is prepared by only adopting magnetron sputtering or ultrasonic rolling, and has the characteristics of ultralow friction factor, low wear rate and high bearing capacity, thus leading the self-lubricating performance of the bearing under the conditions of oil shortage, oil lack and oil cut to be improved.

4. The sputtering target of the present invention has a surface roughness Ra of less than 1mm, a thickness of 50mm or less, and is a non-magnetic material particle-dispersed sputtering target, so that the target material can be stably discharged during sputtering, and the sputtering effect is remarkably improved.

Drawings

FIG. 1 is a schematic structural diagram of an ultrasonic rolling device in an embodiment of the present invention;

FIG. 2 is a schematic diagram of magnetron sputtering in an embodiment of the present invention;

FIG. 3 is a schematic diagram of a magnetron sputtering apparatus and a sample stage according to an embodiment of the present invention;

FIG. 4 is a microstructure diagram of grains of a coating after magnetron sputtering in an embodiment of the invention;

FIG. 5 is a microstructure diagram of coating grains after magnetron sputtering and ultrasonic rolling composite strengthening in the embodiment of the invention.

The labels in the figure are: 1. an ultrasonic generator; 2. a rack housing; 3. a spring; 4. a transducer; 5. an amplitude transformer; 6. a ball rolling tool head; 7. a bearing ring; 8. a machine tool carriage; 9. a sputtering target; 10. a magnetic field; 11. a sample stage.

Detailed Description

The present invention will be described in further detail with reference to fig. 1 to 5 and specific embodiments.

Example one

A method for strengthening the surface of a bearing ring based on magnetron sputtering and ultrasonic rolling composite comprises the following steps:

s1, cleaning the bearing ring 7 substrate made of 42CrMo metal;

s2, preparing a bearing ring coating:

s21, installation: mounting a sputtering target 9 subjected to magnetron sputtering on a direct current cathode, placing a bearing ring 7 on a sample table 11, and fixing the sputtering target 9 to be 150mm away from a base body at a positive pole; the sputtering target 9 is selected from any one of Cu, C, Cr, Ti, Ni, Al, Si and Zr or a metal alloy consisting of any two or more of the metal materials. In this example, the surface roughness Ra of the sputtering target was less than 1mm, the thickness of the sputtering target was 50mm or less, and the sputtering target 9 was a TiSi target.

Referring to fig. 2 and 3, fig. 2 is a schematic diagram of magnetron sputtering in this embodiment, and fig. 3 is a schematic diagram of a magnetron sputtering apparatus and a sample stage in this embodiment. The magnetron sputtering device comprises a plurality of groups of electromagnetically enhanced magnetron sputtering cathodes, the number of the sputtering targets 9 is consistent with that of the magnetron sputtering cathodes, the magnetron sputtering device can form an annular closed magnetic field 10, and the sample table 11 is arranged in the central area of the magnetron sputtering device. The annular closed magnetic field 10 and the central anode electric field form a composite electromagnetic field, so that the movement stroke of electrons can be improved, and the ionization rate of particles is greatly improved.

S22, intermediate-frequency bias flushing: the vacuum chamber was evacuated to 1x10^-3Pa, heating the substrate to 450 ℃, introducing Ar into the vacuum chamber, controlling the flow of Ar to be 250sccm and the working pressure to be 2.5 Pa; starting an intermediate frequency power supply, setting the voltage to be 1000V, and cleaning the surface of the bearing ring 7 for 15 min;

s23, sputtering a priming layer: regulating the flow of Ar to be 100sccm, setting the working pressure to be 1.0Pa, setting the voltage of a medium-frequency bias power supply to be 800V and the duty ratio to be 50%, simultaneously starting a sputtering electrode of a TiSi target, setting the current to be 30A, sputtering for 8min, and sputtering a priming layer on the substrate;

s24, sputtering the bulk layer: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 10sccm and N₂The flow rate of the gas is 400sccm, and the working air pressure is 1.0 Pa; setting the voltage of a medium-frequency bias power supply to be 200V and the duty ratio to be 50%, setting the current of a sputtering power supply to be 80A and the sputtering time to be 30min, and sputtering a main body layer on the priming layer;

s3, preparing a magnetron sputtering coating: simultaneously introducing Ar and N2 into the vacuum chamber, and adjusting the flow rate of Ar to be 50sccm and N₂The flow rate of the sputtering target is 50sccm, the working air pressure is 0.6Pa, the direct-current sputtering power is set to be 150W, and the sputtering time is set to be 30min, so that a magnetron sputtering coating is formed;

s4, ultrasonic rolling reinforcement:

s41, pressing the ultrasonic rolling device on the surface of the bearing ring 7 by a pre-pressing depth to apply a back pressure to the bearing ring 7;

s42, rolling the rolling ball tool head of the ultrasonic rolling device on the surface of the bearing ring 7, and driving the ultrasonic rolling device to do ultrasonic frequency mechanical vibration through input current to finish ultrasonic rolling reinforcement. Thus completing the preparation of the single-layer coating of the bearing ring 7.

The ultrasonic rolling device used for ultrasonic rolling reinforcement is shown in fig. 1, and comprises an ultrasonic generator 1, a bracket shell 2, a spring 3, a transducer 4, an amplitude transformer 5 and a rolling ball tool head 6. The support shell 2 is of a cuboid structure, and the support shell 2 is connected to a machine tool knife rest 8 through a clamping mechanism. The spring 3, the transducer 4 and the amplitude transformer 5 are sequentially connected and arranged in the support shell 2, the upper end of the amplitude transformer 5 extends out of the support shell 2 and then is connected with the spin tool head 6, and the lower end of the amplitude transformer 5 is connected with the transducer 4. The lower end of the energy converter 4 is connected with the upper end of the spring 3, and the lower end of the spring 3 is fixed with the upper bottom surface of the bracket shell 2. The transducer 4 receives an ultrasonic signal sent by the ultrasonic generator 1, transmits ultrasonic frequency mechanical vibration to the amplitude transformer 5, and then applies pressure to the surface of the bearing ring 7 through the rolling ball tool head 6.

Still further, a controller for controlling the ultrasonic rolling device is included, the controller adjusting at least one of the preload depth, the back pressure, and the input current based on the desired residual compressive stress and the real-time rolling force.

By adopting the processing method, the bonding performance of the surface of the bearing ring 7 is improved by measuring the magnetron sputtering and ultrasonic rolling composite strengthening technology.

In view of the thin sputtering layer and the material performance of the coating and the bearing ring substrate, the invention creatively introduces the ultrasonic extrusion technology to carry out ultrasonic rolling strengthening on the surface of the bearing ring after the magnetron sputtering technology is used for sputtering the required coating, thereby improving the bonding strength of the coating and the substrate. As shown in fig. 4 and 5, after the ultrasonic extrusion technology is introduced, the microstructure of the crystal grains of the coating on the surface of the bearing ring is finer, and the density and uniformity of the coating are greatly improved.

Example two

Unlike in example one, sputtering target 9 was a carbon target with a purity of 99.9%; after the step S42 in the first embodiment is completed, the steps S23, S24, S3 and S4 are repeated to complete the preparation of the double-layer coating of the bearing ring 7.

EXAMPLE III

Unlike example one, sputtering target 9 used an aluminum copper target with a purity of 99.9%; after the step S42 in the first embodiment is completed, the steps S23, S24, S3 and S4 are repeated two times to complete the preparation of the multi-layer coating of the bearing ring 7.

Since the material of the sputtering target has an important influence on the quality of the coating, it affects not only the chemical stability of the coating but also whether the coating is strong with the substrate. Therefore, the technical requirements of purity, impurity content, component uniformity, machining precision and the like are met when the target is selected, so that the difference value of the expansion coefficients of the target and the substrate is small, and the influence of the thermal stress of the sputtering coating is reduced.

In this embodiment, the sputtering target 9 is an aluminum copper target with a purity of 99.9%, and when the sputtering power efficiency (sputtering target power density divided by sputtering rate) is selected to be 200-500eV, the uniformity and density of the coating layer sputtered on the substrate are better.

Through experimental evaluation, the multilayer coating prepared by magnetron sputtering and ultrasonic rolling technology has the characteristics of further improved compactness and uniformity, ultralow friction factor, low wear rate and high bearing capacity, and the service life of the bearing is prolonged.

Example four

Unlike in example two, sputtering target 9 was a nonmagnetic material particle-dispersed sputtering target, and the nonmagnetic material particles were Cr₂O₃、B₂O₃、SiO₂、MnO、CoO、SnO2、Mn₃O₄、TiO₂And the oxide content is 5 to 20 mol% of the sputtering target. Preferably Cr₂O₃And CoO as nonmagnetic material particles. The sputtering target can ensure that the target material can stably discharge during sputtering, and the sputtering effect is obviously improved.

It should be noted that, the parts not described in detail in this application are all the prior art.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.