Method and system for surface strengthening of an extra-large thrust taper roller bearing

Abstract

The application provides a method and system for surface strengthening of an extra-large thrust tapered roller bearing, which sequentially performs substrate carburizing-ultrafine grain composite strengthening, precision finishing pretreatment, toughness metal gradient transition layer deposition, multi-element gradient nitride nanometer superlattice coating deposition, and lipid lubrication adaptive laser micro-texture preparation, to construct a multi-scale synergistic strengthening system of substrate strengthening-gradient interface buffer-wear-resistant functional coating-lubricating texture synergistic effect. The application solves the industry pain point of film-substrate interface peeling under heavy load impact through double gradient design, dissipates impact energy and inhibits crack propagation by using nanometer superlattice structure, and realizes friction reduction and temperature control by combining micro-texture matched with lipid lubrication film thickness. After strengthening, the surface hardness is greater than or equal to 1500HV, the coating bonding strength is greater than or equal to 300MPa, the service life of the extra-large thrust tapered roller bearing for a petroleum drilling top drive can be improved to 40,000 hours, and the domestic substitution of high-end heavy load bearings is supported.

Description

Technical Field

[0001] This invention belongs to the field of bearing surface modification and advanced manufacturing technology, specifically relating to a method and system for surface strengthening of extra-large thrust tapered roller bearings, which is particularly suitable for long-life surface strengthening treatment of extra-large thrust tapered roller bearings used in top drive units of oil drilling rigs. Background Technology

[0002] Extra-large thrust tapered roller bearings are the core rotating support components of the top drive unit of oil drilling rigs, directly determining the continuity and safety of drilling operations. Top drive main bearings, represented by the T1120 type bearing, operate under complex conditions of extreme heavy loads, high impacts, and medium to low speeds. Their rated static load can reach 24,500 kN, and their rated dynamic load exceeds 5,800 kN, accompanied by frequent start-stop cycles and formation impact loads. Under these conditions, bearings are highly susceptible to three types of failure problems: first, edge stress concentration leads to plastic deformation and early fatigue spalling of the substrate surface; second, the large abrupt change in modulus between the hard coating and the substrate makes the coating prone to brittle peeling under impact loads; and third, under medium to low speeds and heavy loads, the grease lubrication film is thin, and the mixed lubrication state results in rapid frictional temperature rise, accelerating wear and failure.

[0003] Currently, China relies entirely on multinational corporations such as Timken (USA) and SKF (Sweden) for high-end heavy-duty bearings, resulting in high procurement costs, long delivery cycles, and serious supply chain security risks. Existing bearing surface strengthening technologies mainly fall into two categories: substrate heat treatment strengthening and surface coating strengthening. Conventional carburizing and quenching can improve the surface hardness of the substrate, but it is difficult to resist plastic deformation under extreme impacts, and the residual stress distribution on the surface is uneven. Single hard coatings (such as ordinary CrN coatings) can improve wear resistance, but the film-substrate interfacial modulus changes abruptly, making it prone to coating peeling and transgranular crack propagation under heavy-load impact conditions, resulting in a service life far shorter than imported products. In addition, existing technologies pay little attention to the synergistic matching between surface morphology and grease lubrication, and cannot effectively improve the lubrication state under medium- and low-speed heavy loads.

[0004] Therefore, developing a multi-scale synergistic strengthening method that takes into account the matrix toughness, interfacial bonding strength, surface wear resistance and lubrication compatibility is the key to breaking through the technical bottleneck of domestic production of high-end heavy-duty bearings, in response to the extreme service requirements of extra-large thrust tapered roller bearings. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and solve the technical problems of insufficient service life of extra-large thrust tapered roller bearings due to easy plastic deformation of the matrix, easy peeling of the coating, and poor lubrication matching under extreme heavy load impact conditions. The invention provides a surface strengthening method and system for extra-large thrust tapered roller bearings, which significantly improves the service life of bearings through multi-scale synergistic strengthening and supports the domestic substitution of high-end heavy-duty bearings.

[0006] According to one objective of the present invention, a method for surface strengthening of extra-large thrust tapered roller bearings is provided, comprising the following steps: S1. Matrix strengthening and toughening treatment: The workpiece to be strengthened in the extra-large thrust tapered roller bearing is subjected to controlled atmosphere carburizing and quenching and tempering treatment to form a carburized and hardened layer of a certain depth on the surface of the matrix; then, the surface is strengthened by surface plastic deformation process to control the residual compressive stress on the surface and obtain a gradient structure of high hardness surface layer + strong and tough core, which ensures the surface wear resistance and retains the impact toughness of the core.

[0007] S2. Precision finishing pretreatment: The toughened substrate surface to be strengthened is subjected to precision grinding and ultra-clean cleaning in sequence to remove the surface deformation layer, oxide layer and contaminants, and obtain a clean surface to be deposited with a surface roughness Ra≤0.4μm, so as to provide a qualified substrate for subsequent coating deposition.

[0008] S3. Deposition of a tough metal gradient transition layer: A tough metal gradient transition layer is deposited on the surface to be deposited using physical vapor deposition processes such as multi-target magnetron sputtering. The metal element concentration of the transition layer exhibits a continuous gradient distribution along the depth direction, buffering the difference in elastic modulus between the substrate and the subsequent hard coating, reducing interfacial shear stress concentration, and fundamentally reducing the risk of coating peeling under heavy impact.

[0009] S4. Deposition of Multi-Gradient Nitride Coating: A multi-gradient nitride coating is deposited on the surface of a tough metal gradient transition layer. The coating adopts a multi-layer structure of nanoscale superlattice, consisting of alternating nanoscale nitride sublayers. The content of functional elements in the coating varies in gradient along the depth direction, causing the coating hardness to gradually decrease from the surface layer to the substrate, forming a hardness distribution of a high-hardness, wear-resistant surface layer + gradient transition inner layer. At the same time, the crack deflection effect at the nanoscale superlattice interface is used to dissipate impact energy and suppress crack transgranular propagation.

[0010] S5. Preparation of Grease-Lubricated Adaptive Microtextures: An array of microtextures is prepared on the surface of a multi-gradient nitride coating using an ultrafast laser processing technology. The geometric parameters of the microtextures are precisely matched to the thickness of the grease-lubricated film under bearing service conditions. Secondary lubrication is achieved through oil storage and chip containment and micro-dynamic pressure effects, reducing the coefficient of friction and contact temperature rise under mixed lubrication conditions, and forming a synergistic friction-reducing and wear-resistant effect with the hard coating.

[0011] Furthermore, in step S1, the depth of the carburized and hardened layer is controlled to be 1.5~2.5mm, and the surface hardness of the substrate after quenching and tempering is ≥62HRC; the surface plastic deformation process is preferably ultrasonic impact or surface rolling process, and the surface grains are refined to the submicron level after treatment, the surface residual compressive stress is controlled to -200~-400MPa, and the surface hardness is increased to ≥64HRC.

[0012] Furthermore, in step S3, the tough metal gradient transition layer is a Cr-Ti composite metal layer; during the deposition process, the sputtering power of the Cr target and the Ti target is linearly controlled so that the atomic proportion of Cr element is higher than that of Ti element on the side closer to the substrate, and the atomic proportion of Ti element is higher than that of Cr element on the side closer to the functional coating, so as to achieve a continuous and smooth transition of element concentration; the total thickness of the transition layer is controlled to be 0.3~0.8μm, and the final interfacial bonding strength between the coating system and the substrate is ≥300MPa.

[0013] Furthermore, in step S4, the multi-element gradient nitride coating is a CrAlSiNO gradient coating with a total thickness of 2~5μm; the surface layer of the coating has the highest proportion of Al and Si elements, with a surface hardness ≥1500HV, exhibiting excellent wear resistance and high temperature resistance; along the depth direction, the proportion of Al and Si elements gradually decreases, while the proportion of Cr element gradually increases, achieving a smooth transition of hardness from the surface layer to the transition layer; the coating consists of alternating deposited nanoscale nitride sublayers forming a superlattice structure, with a single sublayer thickness of 10~50nm.

[0014] Furthermore, in step S5, the microtexture is an array of circular pits with a pit diameter of 20~80μm, a depth of 5~15μm, a texture area ratio of 10%~20%, and a depth-to-diameter ratio of 1:4~1:6. This parameter dynamically matches the thickness of the grease lubrication film under low-speed heavy-load conditions in the bearing, so that the surface friction coefficient is ≤0.2 under service conditions.

[0015] This invention also provides a surface strengthening system for ultra-large thrust tapered roller bearings, comprising a substrate toughening module, a precision finishing module, a multi-target vapor deposition module, an ultrafast laser texturing module, and an online detection and closed-loop control module. These modules are sequentially connected to complete the entire processing flow from substrate toughening to final surface texturing. The online detection and closed-loop control module performs online monitoring of key performance parameters for each process, dynamically correcting processing parameters based on a process-performance mapping model to ensure batch consistency.

[0016] The matrix strengthening and toughening module is used to perform controlled atmosphere carburizing, quenching and tempering and surface ultrafine grain strengthening on bearing workpieces to be strengthened, thereby controlling the hardness of the matrix surface, the depth of the hardened layer and the residual stress. The precision finishing module is used to perform precision grinding and ultra-clean cleaning on the toughened substrate surface to be strengthened, and to control the surface roughness to be deposited to meet the preset requirements. The multi-target vapor deposition module is used to sequentially deposit a tough metal gradient transition layer and a multi-element gradient nitride coating on the surface to be deposited, thereby controlling the elemental gradient distribution and the periodic structure of the nano-superlattice of the coating. The ultrafast laser texturing module is used to prepare array-type microtextures on the coating surface that match the lubrication conditions of bearing grease. The online detection and closed-loop control module is used to perform online detection of the surface hardness, interfacial bonding strength, roughness and texture geometry parameters after strengthening, and feeds the detection data back to each processing module to achieve process parameter compensation.

[0017] Furthermore, the multi-target vapor deposition module is a multi-target magnetron sputtering deposition device, equipped with Cr, Al, Si and Ti targets, which can independently control the sputtering power and reactive gas flow rate of each target to achieve continuous gradient control of element concentration; the ultrafast laser texturing module is a picosecond or femtosecond ultrafast laser processing device, which has CNC array processing and online morphology monitoring functions, and can be adapted to high-precision texturing of extra-large bearing surfaces.

[0018] Furthermore, the online detection and closed-loop control module integrates a nanoindenter, a scratch tester, a laser confocal topology analyzer, and an X-ray residual stress analyzer. It can dynamically correct processing parameters based on a preset process-performance mapping model to ensure batch processing consistency ≥95%.

[0019] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method for surface strengthening of extra-large thrust tapered roller bearings.

[0020] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for surface strengthening of extra-large thrust tapered roller bearings.

[0021] The technical solution of this invention constructs a multi-scale synergistic strengthening system of "matrix toughening - gradient interface buffering - wear-resistant functional coating - lubrication texture enhancement," simultaneously addressing the three core challenges of plastic deformation, coating peeling, and lubrication failure under heavy-load impact in ultra-large thrust bearings from four levels: microstructure, interface, coating, and morphology. Through carburizing-ultrafine-grained composite strengthening to enhance the matrix's impact resistance, continuous elemental gradient design to eliminate abrupt changes in film-matrix modulus, nano-superlattice coating to dissipate impact energy, and grease lubrication-adaptive texture to reduce frictional temperature rise, the invention improves interfacial bonding strength, reduces the coefficient of friction, and extends bearing service life to 40,000 hours, providing core technological support for the domestic substitution of high-end heavy-duty bearings. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a process flow diagram of the surface strengthening method for extra-large thrust tapered roller bearings according to the present invention; Figure 2 This is a modular architecture diagram of the extra-large thrust tapered roller bearing surface strengthening system of the present invention; Figure 3 This is a schematic diagram of a computer device according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] I. Method Implementation Examples Example 1 Complete Implementation Method for Strengthening Raceway Surface of T1120 Top Drive Bearing This embodiment describes a complete surface strengthening process for the raceway of an extra-large thrust tapered roller bearing housing ring on a T1120 type oil drilling rig. The base material is GCr15SiMn bearing steel, and the nominal diameter of the raceway working surface is 1120mm. It fully covers all core process steps of this invention and is the optimal implementation method. Figure 1 As shown, the specific process steps are as follows: S1, Matrix strengthening treatment 1. The rough-machined bearing race is placed in a controlled atmosphere pit-type carburizing furnace, using methanol as the carrier gas and kerosene as the carburizing agent. Carburizing is carried out at 920℃ for 8 hours, with a carbon potential of 1.2% in the strong carburizing stage and 0.8% in the diffusion stage. The carburized layer depth is controlled to be 2.0±0.2mm. After carburizing, the furnace temperature is lowered to 840℃ and held for 30 minutes. The workpiece is then oil-quenched and tempered at 180℃ for 4 hours. At this point, the surface hardness of the matrix is ​​approximately 63HRC, and the core impact toughness is ≥40J / cm². 2 After quenching and tempering, the raceway surface is subjected to ultrafine grain strengthening treatment using ultrasonic impact equipment: impact pin diameter 3mm, impact frequency 20kHz, impact energy 0.5J, workpiece rotation speed 10r / min, impact head axial feed speed 0.5mm / r, single-pass processing time 2min / cm. 2 After treatment, the surface grains are refined to the submicron level of 200~500nm, the surface hardness is increased to 65HRC, and the surface residual compressive stress is stabilized at -300~-340MPa, forming a gradient structure of "high hardness and wear-resistant surface + strong and tough core".

[0028] S2, Precision Finishing Pre-treatment 2. The hardened raceway of the seat ring is subjected to CNC forming grinding, consisting of three processes: rough grinding, semi-finish grinding, and finish grinding, with a total grinding allowance of 0.3 mm. Finish grinding uses a resin-bonded CBN grinding wheel at a linear speed of 60 m / s and a feed rate of 0.002 mm / r, ultimately controlling the raceway surface roughness Ra ≤ 0.4 μm and the convexity accuracy to meet P5 tolerance requirements. After grinding, the surface is ultrasonically degreased and cleaned sequentially with acetone and anhydrous ethanol for 15 minutes each to remove grinding fluid, oil, and grinding debris. Then, it undergoes plasma cleaning for 5 minutes to further remove organic contaminants. After cold air drying, a clean surface for deposition is obtained.

[0029] S3, Deposition of ductile metal gradient transition layer 3. A Cr-Ti tough metal gradient transition layer was deposited using a multi-target magnetron sputtering system. The workpiece was placed in a vacuum chamber, and the base vacuum was evacuated to 4 × 10⁻⁶. -3Below Pa, high-purity argon gas (99.999% purity) is introduced at a working pressure of 0.5 Pa. A -150V pulsed bias is applied to the workpiece, and the workpiece's revolution speed is 5 r / min. First, the Cr target (99.95% purity) is turned on with a sputtering power of 3kW for 10 minutes to form a pure Cr underlayer. Then, within 30 minutes, the Cr target power is linearly reduced to 0.5kW, while the power of the Ti target (99.95% purity) is simultaneously linearly increased from 0.5kW to 3kW, achieving a continuous reverse gradient change in Cr and Ti element concentrations. The final transition layer has a total thickness of approximately 0.5μm, with approximately 85% Cr atoms near the substrate and approximately 80% Ti atoms near the functional coating.

[0030] S4, multi-gradient nitride coating deposition 4. A CrAlSiNO multi-element gradient nitride coating was deposited on top of the transition layer. High-purity nitrogen and trace amounts of oxygen were introduced into the vacuum chamber at a nitrogen-argon volume ratio of 1:3, with a working pressure of 0.6 Pa and a workpiece bias voltage adjusted to -80 V. The total deposition time was 90 min, during which the power of each target was dynamically controlled: the Cr target power was gradually reduced from 2 kW to 0.8 kW, the Al target power from 1 kW to 2.5 kW, and the Si target power from 0.3 kW to 1 kW. Elemental gradient control ensured that the Al and Si elements had the highest proportion on the surface of the coating, gradually decreasing along the depth direction while the Cr element proportion gradually increased. The coating consists of alternating stacked CrN, AlN, and Si3N4 nanocrystalline sublayers forming a superlattice structure, with a single sublayer thickness of approximately 30 nm and a total coating thickness of approximately 3.5 μm. The surface hardness of the coating reached 1620 HV, with the hardness decreasing gradually along the depth direction without abrupt interface changes.

[0031] S5, Preparation of Grease-Lubricated Adaptive Microtextures A picosecond ultrafast laser was used to fabricate a circular pit array microtexture on the coated surface. Laser parameters: wavelength 1064nm, pulse width 10ps, repetition frequency 100kHz, single pulse energy 20μJ; a galvanometer scanning method was used, with the workpiece rotating synchronously, and the pits arranged equidistantly along the circumference of the raceway. Microtexture parameters: pit diameter 50μm, depth 10μm, center-to-center distance between adjacent pits 150μm, texture area ratio approximately 12%, depth-to-diameter ratio 1:5, dynamically matching the grease lubrication film thickness (0.8~1.2μm) of the T1120 bearing under rated operating conditions. After processing, the bearing raceway was ultrasonically cleaned with anhydrous ethanol for 5 minutes to remove molten spatter, ultimately obtaining a reinforced bearing raceway.

[0032] Testing revealed that the surface hardness of the reinforced raceway in this embodiment is 1620 HV, and the interfacial bonding strength between the coating system and the substrate is 345 MPa. Under grease lubrication conditions with a contact stress of 3 GPa, a rotational speed of 120 r / min, and a temperature of 80°C, the stable coefficient of friction is 0.17, and the wear rate is reduced by 65% ​​compared to ordinary carburized bearings. Full-size bench testing verified that the long-term operating temperature under rated load is stable at 108°C, and the expected service life can reach 42,000 hours.

[0033] Example 2 T1120 bearing tapered roller surface strengthening application This embodiment strengthens the outer circle of the tapered rollers and the spherical base surface of the T1120 bearing. The base material is GCr15 high hardenability bearing steel, which is suitable for the machining of the roller surface and the requirement for high consistency. The process parameters are adjusted for the roller size and morphology based on Embodiment 1. 1. Matrix strengthening and toughening: The depth of the carburized layer of the roller blank is controlled to 1.8mm. After quenching and tempering, a precision surface rolling process is used for ultra-fine grain strengthening. The rolling pressure is 1.5kN and the feed rate is 0.1mm / r. After treatment, the surface hardness is 64.5HRC and the residual compressive stress is about -280MPa.

[0034] 2. Precision finishing: The outer diameter of the roller and the spherical base surface are subjected to ultra-precision grinding. The surface roughness of the outer diameter Ra≤0.2μm, the surface roughness of the spherical base surface Ra≤0.1μm, and the diameter variation of the rollers in the same batch ≤0.003mm.

[0035] 3. Coating deposition: A planetary clamping method with revolution and rotation is adopted to ensure the uniformity of the coating on the roller surface; the thickness of the Cr-Ti transition layer is 0.4μm, the total thickness of the CrAlSiNO coating is 2.5μm, and the surface hardness is 1580HV.

[0036] 4. Microtexture preparation: The pits are 30μm in diameter and 6μm in depth, and are evenly spaced along the direction of the roller generatrix. The texture area accounts for 15%, which is suitable for the lubrication requirements of roller line contact conditions.

[0037] Testing showed that the interface bonding strength of the roller after reinforcement in this embodiment is 320MPa, the coefficient of friction under heavy-duty grease lubrication is 0.18, the matching with the raceway of the seat ring in embodiment 1 is good, the service life of the whole machine is comparable to that of embodiment 1, and the consistency of processing in the same batch is ≥96%.

[0038] Example 3 Application of reinforcement of working face of sidewall under heavy-duty impact conditions This embodiment strengthens the bearing flange guide surface, which is mainly subject to sliding friction and bears the impact load of the large end of the roller, making it a high-risk area for bearing failure. The process parameters are optimized for impact conditions based on Embodiment 1: 1. Matrix strengthening and toughening: The depth of the carburized layer at the edge is 2.2mm, the ultrasonic impact energy is increased to 0.7J, and the residual compressive stress on the surface is about -380MPa, which further enhances the resistance to impact plastic deformation.

[0039] 2. Coating design: The thickness of the Cr-Ti transition layer is increased to 0.8μm to enhance the interface buffering capacity; the total thickness of the CrAlSiNO coating is 5μm, and the superlattice period is adjusted to 20nm to further improve the crack deflection and impact energy dissipation capabilities.

[0040] 3. Microtexture optimization: An elliptical pit texture is adopted, with the major axis arranged along the sliding direction, a major diameter of 60μm, a minor diameter of 30μm, a depth of 12μm, and a texture ratio of 18%, which enhances the oil storage and friction reduction effect in the sliding direction.

[0041] Impact wear tests have verified that the reinforced flange in this embodiment showed no coating peeling under 1000 hours of cyclic testing under 120% overload impact conditions, and the wear amount was further reduced by 12% compared to Example 1, making it suitable for extreme impact service scenarios.

[0042] II. System Implementation Examples Example 4 Surface strengthening system for extra-large thrust tapered roller bearings This embodiment is a dedicated system for implementing the above-mentioned enhancement method. The overall system architecture is as follows: Figure 2 As shown, it specifically includes: Matrix toughening treatment module 1. Composed of a controllable atmosphere pit-type carburizing furnace, quenching press, low temperature tempering furnace and ultrasonic impact equipment, it can complete carburizing, quenching and tempering and surface ultra-fine grain strengthening of bearing workpieces; it has a built-in carbon potential, temperature and time closed-loop control unit, the carburized layer depth control accuracy is ±0.1mm, and the residual stress control accuracy is ±30MPa.

[0043] Precision finishing module 2. Composed of a CNC forming grinder, an ultrasonic cleaning line, and a plasma cleaner, it can perform precision grinding and ultra-clean cleaning of extra-large bearing raceways, flanges, and rollers; equipped with an online roughness detection unit, it can provide real-time feedback on grinding quality and compensate for grinding wheel dressing parameters to ensure that the surface roughness of the surface to be deposited is stable and meets the standards.

[0044] Multi-target vapor deposition module 3. This is a vertical multi-target magnetron sputtering coating equipment, equipped with four independently controlled metal targets: Cr, Ti, Al, and Si. It is equipped with three high-precision mass flow meters for argon, nitrogen, and oxygen. It supports linear gradient power programming, enabling continuous gradient control of element concentration and precise deposition of nanoscale superlattice structures. The equipment has an effective coating diameter of 1500mm, suitable for full-circle coating of T1120 and larger bearing races.

[0045] Ultrafast laser texturing module 4. It is a five-axis linkage picosecond laser processing system, equipped with a 1064nm picosecond laser and a high-speed galvanometer scanning head, which supports the precise processing of array textures on large curved surfaces; it has a built-in laser confocal morphology online monitoring unit, which can detect the diameter, depth and arrangement accuracy of the pits in real time, and automatically compensate for the laser energy and scanning path.

[0046] Online detection and closed-loop control module Integrating a nanoindenter, scratch tester, laser confocal microscopy topology analyzer, and X-ray residual stress analyzer, it can perform online spot checks on the hardness, bonding strength, roughness, residual stress, and texture parameters of workpieces output from each process. With a built-in process-performance mapping database and compensation algorithm, it can automatically correct process parameters such as carburizing time, sputtering power, and laser energy for the next batch based on the test results, ensuring batch processing consistency ≥95%.

[0047] System operation process: The workpiece first enters the substrate toughening treatment module to complete the microstructure regulation, and then obtains a qualified surface to be deposited through the precision finishing treatment module. Then, it passes through the multi-target vapor deposition module and the ultrafast laser texture processing module to complete the coating deposition and texture preparation. The entire process is monitored for quality and parameter feedback by the online detection and closed-loop control module, and finally outputs qualified reinforced bearing parts.

[0048] III. Comparative Example To verify the technical effects of each core step of the present invention, the following three sets of comparative examples were set up. Except for the specified variables, the substrate material, basic heat treatment and test conditions were kept the same as in Example 1.

[0049] Comparative Example 1: Conventional carburizing and quenching process (existing common process) Using only conventional carburizing and quenching heat treatment, without coating deposition or microtexturing preparation, the carburized layer depth is 2.0 mm, and the surface hardness is 62 HRC. Under the same conditions, the surface friction coefficient is 0.35, and the wear rate is 3.2 times that of Example 1; the expected life of bench testing is about 12,000 hours, and surface plastic deformation and fatigue spalling are prone to occur under heavy impact.

[0050] Comparative Example 2: Single CrN Coating Process Without Gradient Transition Layer The carburizing and quenching, ultrafine grain strengthening, and microtexturing steps were retained, but the Cr-Ti gradient transition layer was eliminated. A single layer of ordinary CrN coating was directly deposited on the substrate surface, with a total coating thickness of 3.5 μm. Under the same conditions, the surface hardness was 1200 HV, and the interfacial bonding strength was only 180 MPa. After a 120% overload impact test, the coating peeled off in flakes, and after 2000 hours of heavy-load operation, large-area wear failure occurred, failing to meet the requirements for long-life service.

[0051] Comparative Example 3: Gradient Coating Process Without Microtexture The entire process of substrate toughening, gradient transition layer, and gradient coating is retained, but surface microtexture is not prepared. Under identical testing conditions: surface hardness is 1610 HV, and interfacial bonding strength is 340 MPa, comparable to Example 1; however, the coefficient of friction under heavy-duty grease lubrication is 0.26, 53% higher than in Example 1, and the operating temperature rise reaches 135°C, exceeding the service temperature limit of 120°C. The grease aging rate is accelerated, and the expected lifespan is approximately 28,000 hours.

[0052] The core performance of each embodiment and the comparative example is compared in the table below:

[0053] As can be seen from the comparison, the present invention achieves high hardness, high bonding strength, low friction coefficient and long service life through the synergistic effect of "matrix toughening - gradient transition layer - gradient superlattice coating - lubrication adaptation texture". Each core step is indispensable and together solves the failure problem of ultra-large thrust tapered roller bearings under heavy load impact.

[0054] Those skilled in the art will understand that all or part of the steps in the above embodiments can be implemented by hardware related to computer program instructions. The program can be stored in a computer-readable storage medium, and when executed, it can implement the steps of the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, and optical disks.

[0055] The embodiments of this specification also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a computer, implements the surface strengthening method for extra-large thrust tapered roller bearings described in the above embodiments.

[0056] This specification also provides a computer program product containing instructions that, when executed by a computer, cause the computer to implement the surface strengthening method for extra-large thrust tapered roller bearings described in the above embodiments.

[0057] This specification also provides a computer device, including a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the surface strengthening method for extra-large thrust tapered roller bearings described in the above embodiments.

[0058] like Figure 3 As shown, the computer device can be a terminal, and its internal structure diagram can be as follows: Figure 3As shown. The computer device includes a processor, memory, and communication interface connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a surface strengthening method for ultra-large thrust tapered roller bearings.

[0059] Compared with the prior art, the present invention has the following significant technical effects: This invention employs multi-scale synergistic strengthening to comprehensively overcome performance bottlenecks: it constructs a four-level synergistic strengthening system consisting of matrix carburization with ultrafine grains for toughening, a gradient metal transition layer, a multi-component gradient nitride superlattice coating, and a lubrication-matching microtexture. This system simultaneously solves four core problems: matrix impact resistance and plasticity, film-substrate interfacial adhesion, surface wear resistance, and lubrication compatibility, thus overcoming the performance limitations of single strengthening methods. Bench tests have verified that the strengthened bearing has an expected service life of over 40,000 hours, reaching the advanced level of similar international products.

[0060] This invention solves the problem of interface failure through a dual gradient design: by using a metal element gradient transition layer and a functional element gradient coating, the abrupt change in elastic modulus between the substrate and the hard coating is eliminated, and the interface bonding strength is increased to more than 300MPa. Compared with the interface bonding strength of a single coating, it is more than 70% stronger, which can effectively resist the brittle peeling of the coating under heavy impact.

[0061] The present invention improves the impact resistance performance with a nanoscale superlattice structure: the coating adopts a nanoscale periodic superlattice structure, which utilizes the crack deflection and energy absorption effect of the heterogeneous interface to significantly improve the impact fatigue resistance performance and delay the mechanical property decay at high temperature, and can be adapted to the high temperature service environment of top drive bearings below 120°C.

[0062] This invention achieves friction reduction and temperature control through texture-lubrication synergy: the microtexture parameters are precisely matched with the grease film thickness, which can significantly improve the oil film load-bearing capacity under mixed lubrication conditions of medium and low speed and heavy load, and reduce the coefficient of friction to below 0.2, which is more than 30% lower than that of the untextured surface, effectively suppressing friction temperature rise and extending the service life of the grease.

[0063] This invention has strong engineering adaptability and supports domestic substitution: the process can be adapted to the batch processing of extra-large bearings, and the reinforced bearings can directly replace imported top drive bearings, reducing the cost of a single set of purchases and shortening the supply cycle, resulting in significant economic benefits and industrial value.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for surface strengthening of an extra-large thrust tapered roller bearing, characterized in that, Includes the following steps: S1. Matrix strengthening and toughening treatment: The workpiece to be strengthened in the extra-large thrust tapered roller bearing is subjected to controlled atmosphere carburizing and quenching and tempering treatment to form a carburized and hardened layer on the surface of the matrix; then the surface is strengthened by surface plastic deformation process to control the residual compressive stress on the surface and obtain a matrix structure with a high hardness surface and a strong and tough core. S2. Precision finishing pretreatment: The toughened substrate surface to be strengthened is subjected to precision grinding and ultra-clean cleaning in sequence to remove the surface deformation layer and contaminants, and obtain a surface roughness Ra≤0.4μm to be deposited. S3. Deposition of tough metal gradient transition layer: A tough metal gradient transition layer is deposited on the surface to be deposited using physical vapor deposition. The concentration of metal elements in the transition layer is continuously gradient-distributed along the depth direction, so as to achieve a smooth transition of elastic modulus between the substrate and the subsequent functional coating. S4. Deposition of multi-gradient nitride coating: A multi-gradient nitride coating is deposited on the surface of the tough metal gradient transition layer. The coating is a nano-superlattice multilayer structure. The content of functional elements in the coating changes in a gradient along the depth direction, so that the hardness of the coating gradually decreases from the surface to the substrate. S5. Preparation of Grease-Lubricated Adaptive Microtexture: An array of microtextures is prepared on the surface of the multi-gradient nitride coating using an ultrafast laser processing technology. The geometric parameters of the microtextures are matched with the thickness of the grease-lubricated film under bearing service conditions, so as to synergistically achieve the effects of debris capture and secondary lubrication.

2. The surface strengthening method for extra-large thrust tapered roller bearings according to claim 1, characterized in that, In step S1, the depth of the carburized and hardened layer is 1.5~2.5mm, and the surface hardness of the substrate after quenching and tempering is ≥62HRC; the surface plastic deformation process is ultrasonic impact or surface rolling process, and after treatment, the surface grains are refined to the submicron level, the surface residual compressive stress is -200~-400MPa, and the surface hardness is ≥64HRC.

3. The surface strengthening method for extra-large thrust tapered roller bearings according to claim 1, characterized in that, In step S3, the tough metal gradient transition layer is a Cr-Ti composite metal layer; during the deposition process, the sputtering power of the Cr target and the Ti target is linearly controlled so that the atomic ratio of Cr element is higher than that of Ti element on the side closer to the substrate, and the atomic ratio of Ti element is higher than that of Cr element on the side closer to the functional coating; the total thickness of the transition layer is 0.3~0.8μm, and the interfacial bonding strength between the coating system and the substrate is ≥300MPa.

4. The surface strengthening method for extra-large thrust tapered roller bearings according to claim 1, characterized in that, In step S4, the multi-element gradient nitride coating is a CrAlSiNO gradient coating with a total thickness of 2~5μm; the surface layer of the coating has the highest proportion of Al and Si elements, and the surface hardness is ≥1500HV; the proportion of Al and Si elements gradually decreases along the depth direction, while the proportion of Cr element gradually increases; the coating is composed of alternating deposited nanoscale nitride sublayers forming a superlattice structure, with a single sublayer thickness of 10~50nm.

5. The surface strengthening method for extra-large thrust tapered roller bearings according to claim 1, characterized in that, In step S5, the microtexture is a circular pit array with a pit diameter of 20~80μm, a pit depth of 5~15μm, a texture area ratio of 10%~20%, and a depth-to-diameter ratio of 1:4~1:

6. The microtexture dynamically matches the thickness of the grease lubrication film under heavy load conditions of the bearing, so that the surface friction coefficient is ≤0.2 under service conditions.

6. A surface strengthening system for extra-large thrust tapered roller bearings for implementing the surface strengthening method for extra-large thrust tapered roller bearings according to any one of claims 1-5, characterized in that, include: The matrix strengthening and toughening module is used to perform controlled atmosphere carburizing, quenching and tempering and surface ultrafine grain strengthening on bearing workpieces to be strengthened, thereby controlling the hardness of the matrix surface, the depth of the hardened layer and the residual stress. The precision finishing module is used to perform precision grinding and ultra-clean cleaning on the toughened substrate surface to be strengthened, and to control the surface roughness to be deposited to meet the preset requirements. A multi-target vapor deposition module is used to sequentially deposit a tough metal gradient transition layer and a multi-element gradient nitride coating on the surface to be deposited, thereby controlling the elemental gradient distribution and the periodic structure of the nano-superlattice of the coating. An ultrafast laser texture processing module is used to prepare array-type microtextures on the coating surface that match the lubrication conditions of bearing grease. It also includes an online detection and closed-loop control module, which is used to detect the surface hardness, interfacial bonding strength, roughness and texture geometry parameters of the strengthened surface online, and feed the detection data back to each processing module to achieve process parameter compensation.

7. The surface strengthening system for extra-large thrust tapered roller bearings according to claim 6, characterized in that, The multi-target vapor deposition module is a multi-target magnetron sputtering deposition device, equipped with Cr, Al, Si and Ti targets, and can independently adjust the sputtering power and reactive gas flow rate of each target to achieve continuous gradient control of element concentration; the ultrafast laser texturing module is a picosecond or femtosecond ultrafast laser processing device, with CNC array processing and online morphology monitoring functions.

8. The surface strengthening system for extra-large thrust tapered roller bearings according to claim 6, characterized in that, The online detection and closed-loop control module integrates a nanoindenter, a scratch tester, a laser confocal topography instrument, and an X-ray residual stress analyzer. It can dynamically correct processing parameters based on a preset process-performance mapping model to ensure batch processing consistency ≥95%.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the surface strengthening method for extra-large thrust tapered roller bearings as described in any one of claims 1 to 5.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the surface strengthening method for extra-large thrust tapered roller bearings as described in any one of claims 1 to 5.

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