61 results about "Contact fatigue" patented technology

The invention provides a residual life prediction method and device of a chip test connector and a storage medium, and the method comprises the steps: firstly collecting the current data of a loop where the chip test connector is located in a first time period, and determining the current rise rate, the current sag feature and the current noise feature based on the current data; and inputting the current rise rate, the current sag feature and the current noise feature into a pre-trained prediction model to obtain the residual life of the chip test connector output by the prediction model. According to the application, multi-dimensional features such as the current rising rate, the current sag feature and the current noise feature are extracted according to the dynamic current, the features influencing the service life of the chip test connector can be monitored in real time, and the influence of contact fatigue, arc risk and connection surface dirt in the working process of the chip test connector is comprehensively considered; the prediction accuracy is improved, and various problems caused by performance reduction of the chip test connector are reduced.

The invention provides a gear contact fatigue life prediction method considering macro-micro geometric parameter influence. The method comprises the following steps: firstly, establishing a tooth surface contact-dynamics analysis model considering macro-micro geometric parameter influence, and calculating tooth surface dynamic load distribution; secondly, establishing a calculation model of the stress on the surface and below the surface of the gear considering the influence of lubrication and surface roughness, and calculating the oil film pressure and the stress on the surface and below the surface of the gear; and finally, establishing a gear contact fatigue life prediction model considering the influence of macro and micro geometric parameters, and calculating the contact fatigue life of the gear. According to the method, the influence of the rigidity change of the gear on the contact fatigue life of the gear is considered, the contact fatigue life of gears with different web structures is predicted, and the deviation between the contact fatigue life obtained through theoretical calculation and the actual contact fatigue life is reduced. Meanwhile, the method considers the influence of the error on the contact fatigue life of the gear, so that the prediction of the contact fatigue life of the gear with the modification and the error is realized.

The present application belongs to the field of rail material research and manufacturing, and specifically discloses a rail structure for a subway humid environment. According to the distribution of pearlite lamellar spacing, the rail head cross-section structure can be divided into cap layer 1, cap layer 2, cap layer 3 and base material layer. The pearlite lamellar spacing distribution of cap layer 1 is 130-150 nm, the pearlite lamellar spacing distribution of cap layer 2 is 90-120 nm, the pearlite lamellar spacing distribution of cap layer 3 is 140-170 nm, and the pearlite lamellar spacing distribution of the base material layer is 200-230 nm. The present application designs cap-shaped structures with different depths and different pearlite lamellar spacing in the rail head. By accelerating the cooling speed of the heat treatment of the hot-rolled rail in different stages, the reasonable gradient structure distribution of the pearlite structure of the rail material is realized, the expansion speed of the rolling contact fatigue crack of the rail in the humid environment to the internal material is effectively slowed down, the rolling contact fatigue damage is reduced, and thus the comprehensive performance and service life of the rail are improved.

The invention relates to the technical field of metal part machining, in particular to a heavy-duty gear and a preparation method and application thereof. The preparation method of the heavy-duty gear comprises the following steps that S1, intermittent LIS bombardment is conducted on a gear base body; s2, intermittently depositing Cr atoms on the gear base body to obtain a Cr base layer; s3, a CrAlC transition layer and a Cr-Al-GLC layer are sequentially deposited on the Cr base layer; wherein the setting of the working time and the intermittent time of the intermittent LIS bombardment process and the intermittent Cr atom deposition process meets the condition that the temperature of the gear base body is maintained to be 140 DEG C or below. Through intermittent LIS bombardment and intermittent Cr atom deposition processes, the temperature of a gear base body is strictly controlled to be 140 DEG C or below, attenuation of residual compressive stress on the surface of the gear is effectively prevented, the residual compressive stress on the surface (0-25 microns) of the gear is kept at 680-920 MPa, and therefore the contact fatigue strength of the gear is improved, and the service life of the gear is prolonged. And fatigue failure caused by insufficient residual compressive stress of the gear under the heavy load working condition is avoided.

The application discloses an automatic folding and sealing box machine photoelectric detection device and method and the automatic folding and sealing box machine, and belongs to the technical field of automatic packaging and transportation. The device comprises a conveying line, a pair of photoelectric switches and a mounting bracket. The pair of photoelectric switches comprises a transmitting end and a receiving end, and the transmitting end and the receiving end are arranged on the two sides of the conveying line. The transmitting end is used for transmitting a detection light beam, and the receiving end is used for receiving the detection light beam in a non-contact manner and outputting a detection signal when the light beam is interrupted. The mounting bracket is used for fixing the transmitting end and the receiving end. The application does not need the direct collision between materials and detection components, avoids the mechanical damage to the box body, eliminates the problems of the wear, fracture and contact fatigue oxidation of a traditional travel switch contact rod, greatly improves the service life of the detection device, and reduces the equipment maintenance frequency and maintenance cost.

The invention discloses a time-varying reliability optimization design method and system for a helical gear. The method comprises the following steps: establishing a gear reliability optimization design model which takes gear volume minimization as an optimization target and takes full-life-cycle time-varying reliability as a constraint; constructing a gear contact fatigue time-varying limit state function coupling the time-varying load spectrum and the material strength degradation model; constructing a time-varying reliability analysis module based on an agent model and an active learning strategy so as to evaluate the time-varying limit state function; and an optimization algorithm is adopted to solve the gear reliability optimization design model, the time-varying failure probability of the candidate scheme is evaluated by calling the time-varying reliability analysis module, the time-varying reliability constraint is processed according to the time-varying failure probability, and optimal gear design parameters meeting the constraint are output. According to the method, efficient cooperation of time-varying reliability high-precision evaluation and lightweight optimization design is realized, and the problem that a time-varying factor cannot be considered in optimization due to too high analysis cost in a traditional method is solved.

This invention provides a single-rod, dual-pump synchronously driven, alternating, continuous, ultra-low alternating load deep pumping lifting system, comprising a double-rod working cylinder, at least one set of gear assembly supports, and two parallel-arranged pumps. The upper end of the gear assembly supports is connected to the double-rod working cylinder, and the lower end is connected to the two parallel-arranged pumps via double-pump couplings. Two parallel rack rods are provided inside the working cylinder, and the lower ends of the two rack rods are connected to the plungers of the two pumps respectively. Racks for meshing with gears installed in the gear assembly supports are fixed on the two rack rods. Flow holes are provided on the gear assembly supports. This new lifting system can significantly reduce or even completely avoid contact fatigue damage at tubing thread connections, reduce the number of wells lying down due to tubing thread leakage, and lower the maintenance costs of mechanically operated wells. It also achieves continuous wellhead drainage and improved pump efficiency through deep pumping with small pumps.

The invention discloses a subsurface contact fatigue damage calculation method considering surface integrity characteristic parameters, relates to the technical field of mechanical part fatigue analysis in engineering, and solves the problem that existing mainstream fatigue analysis software lacks a subsurface contact fatigue analysis module. The method comprises the steps of finite element model input and subsurface layer adaptive grid generation, surface integrity characteristic parameter gradient curve characterization, surface integrity characteristic parameter coupling effect model establishment, and subsurface fatigue damage and danger depth prediction. The core of the method is to generate a sub-surface layer adaptive grid, characterize a gradient curve of surface integrity characteristic parameters changing along the depth, and establish a coupling effect model of each characteristic parameter to sub-surface contact fatigue damage, thereby realizing damage prediction and dangerous area positioning functions.

The utility model discloses a linear guide rail structure for industrial automatic control equipment, which comprises a linear guide rail main body and a clamping slide block, the clamping slide block is slidably arranged on the front side of the surface of the linear guide rail main body, two sides of the inner cavity of the clamping slide block are respectively provided with a slide groove, the clamping slide block comprises a material base layer, a reinforcing layer and a wear-resistant layer, and the material base layer is provided with a plurality of grooves. The reinforcing layer is arranged on the inner surface of the material base layer, the wear-resistant layer is arranged on the inner surface of the reinforcing layer, the reinforcing layer comprises a composite material layer and a steel alloy layer, and the steel alloy layer is arranged on the outer surface of the composite material layer. Through the arrangement of the reinforcing layer, the clamping sliding block has quite high hardness, abrasion resistance and contact fatigue strength, meanwhile, the core part keeps good toughness and can bear high impact load, the good effect of improving the abrasion resistance of the clamping sliding block is achieved, and the problem that due to the fact that a traditional clamping sliding block is poor in abrasion resistance, when the clamping sliding block is used for a long time, the abrasion resistance of the clamping sliding block is poor is solved. And the clamping sliding block is damaged due to abrasion of the clamping sliding block.

The invention provides a method for measuring and calculating the abrasion loss of an involute gear based on a self-reference datum. The method does not need to depend on an external reference, measurement errors caused by reference deviation are effectively reduced, an accurate and rapid calculation method is found, accurate calculation of different involute gear abrasion losses can be achieved by changing the basic parameters of the gear, and the calculation accuracy is improved. Similarly, the abrasion loss of corresponding involute parts, such as involute splines, can be accurately calculated. And a key technical support is provided for wear loss precision control and data reliability of the gear tooth surface in gear wear and gear contact fatigue tests and process and parameter design of the gear.

This invention applies selective laser cladding (SLS) technology to the fabrication of reducer pin tooth housings, designing a lightweight, high-strength pin tooth housing with both material and structural gradients. In terms of materials, a gradient material layer-by-layer printing process is employed, with the outer layer using high-strength alloy steel as the base layer, the middle layer using GCr15 bearing steel powder, and the inner gear surface coated with a thin layer of AlCoCrFeNi high-entropy alloy powder. A certain proportion of transition zone material is incorporated between each layer to enhance the wear resistance and contact fatigue strength of the pin tooth housing. Structurally, a certain structural gradient is used, with a three-layer structure designed using UG 3D modeling software. The top and bottom layers are solid and gapless, while the middle layer uses a negative Poisson's ratio hollow structure, significantly reducing the weight of the pin tooth housing and achieving lightweight design. This dual-gradient design allows the reducer to maintain better overall mechanical performance while achieving a lightweight design.

The application provides a measurement and calculation method based on self-reference reference involute gear wear amount. The method does not need to rely on external reference, effectively reduces the measurement error caused by reference deviation, and finds an accurate and fast calculation method. By changing the basic parameters of the gear, the accurate calculation of different involute gear wear amounts can be realized, and the wear amounts of corresponding involute parts, such as involute splines, can also be accurately calculated. The method provides key technical support for the precision control and data reliability of the gear tooth surface wear amount in the gear wear and gear contact fatigue test, and the process and parameter design of the gear.

The invention relates to the technical field of microstructure refinement and homogenization of bearing steel, and specifically relates to a high-carbon bearing steel and a method of preparing same. The high-carbon bearing steel of the invention has the following chemical composition: C: 0.80˜1.20 wt %, Cr: 0.40˜2.0 wt %, Mn: 0.15˜0.75 wt %, Si: 0.15˜0.75 wt %, Nb: 0˜0.20 wt %, Mo: 0˜0.20 wt %, V: 0˜0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities; the contents of Nb, Mo and V are not 0 at the same time. According to the invention, microalloying elements such as Nb, Mo and V, in combination with other elements, are added into the high-carbon bearing steel to effectively refine the bearing steel matrix and promote the precipitation of a large amount of nano-carbides, thereby enhancing the contact fatigue life of the high-carbon bearing steel.

The invention provides the application of the test method in testing the rolling contact fatigue performance of the steel rail material in a humid and / or corrosive environment. The invention also provides a test method for testing the rolling contact fatigue performance of the steel rail material, which comprises the following steps: preparing a steel rail test sample, simulating a humid and corrosive environment, and carrying out a double-wheel rolling contact fatigue test according to test requirements; and evaluating the contact fatigue performance of the sample through weightlessness, vibration signals and the surface state of the sample. The test mode better conforms to the actual service condition of the steel rail line in the humid and corrosive environment, and the test result is more accurate and effective. The steel rail material rolling contact fatigue test method provided by the invention can evaluate the contact fatigue performance of multi-steel-grade steel rails in a humid and corrosive environment, and parameters such as corrosive liquid and test pause interval time can be adjusted according to actual requirements. The method is suitable for test evaluation of various service conditions such as coastal, tunnel and plateau, and has a good application prospect.

This invention provides a high surface hardness gear steel for new energy vehicles, its production method, and heat treatment process. The composition is: C 0.25-0.30%, Si 0.25-0.45%, Mn 1.15-1.35%, P ≤0.015%, S ≤0.015%, Cr 1.11-1.27%, Mo 0.7-1.00%, Al 0.025-0.035%, Ti 0.03-0.05%, Ni 1.4-1.6%, Cu ≤0.2%, [N] 30-50ppm, TO ≤15ppm, [H] ≤1.5ppm, with the remainder being Fe and unavoidable impurity elements. After isothermal normalizing pretreatment + carburizing gas quenching + low-temperature tempering, the carburized layer grain size is ≥10.0 grade, and the surface hardness is ≥800HV. 10 ≥3.0×10 7 L 50 ≥6.5×10 7 This meets the requirements of new energy vehicles for high contact fatigue performance.

The invention discloses a moderate-strength contact-fatigue-resistant bainite steel rail and a preparation method thereof, and belongs to the technical field of steel rail preparation. The steel rail comprises the following chemical components in percentage by weight: 0.22%-0.26% of C, 1.00%-1.20% of Si, 1.25%-1.45% of Mn, 0.25%-0.6% of Cr, 0.2%-0.4% of Mo, 0.025%-0.040% of Nb, less than or equal to 0.015% of P, less than or equal to 0.010% of S and the balance of Fe and inevitable impurities. The moderate-strength contact fatigue-resistant bainite steel rail for the freight railway curve line is prepared by combining low-cost alloy component design with a controlled cooling process, so that the rolling contact fatigue resistance of the steel rail is improved while the strength and the toughness of the steel rail are ensured; and in the using process, abrasion and rolling contact fatigue damage can be effectively controlled, the service life of the steel rail is remarkably prolonged, and the grinding and maintaining cost of the steel rail is reduced.

The invention discloses a forging device for metal processing and manufacturing and capable of improving contact fatigue strength of tooth surfaces, and relates to the technical field of metal forging and polishing. The forging and pressing device for metal machining and manufacturing and capable of improving the contact fatigue strength of the tooth surface comprises a box body, a supporting frame is arranged at the top of the rear side of the box body, and rotary driving equipment is movably connected into the box body; an electric push rod is fixedly connected to the top of the supporting frame, a hollow rod is fixedly connected to the bottom of the electric push rod, a reciprocating lead screw is movably connected to the interior of the hollow rod, a threaded sliding block is in threaded connection to the outer side of the reciprocating lead screw, and the outer side of the threaded sliding block is slidably connected with the hollow rod through a sliding groove; the outer side of the threaded sliding block is rotationally connected with a guide block through a first rotating shaft, and the first rotating shaft is movably connected with the guide block through a transmission piece. According to the forging and pressing device for metal machining and manufacturing and capable of improving the tooth surface contact fatigue strength, through vertical reciprocating motion and angle change of the guide block, parts are polished more completely, and the working efficiency of equipment is improved.

The application relates to the field of material service behavior evaluation, in particular to service behavior evaluation of ceramic balls in high-end bearings, and more specifically to a ceramic ball rolling contact fatigue performance testing device and testing method simulating the structure and lubrication of an angular contact ceramic ball bearing. The device comprises a fixing plate, a stand, a limiting plate, an upper thrust bearing, a lower thrust bearing, an upper conical ring base, a lower conical ring base, an upper conical ring, a lower conical ring, a retainer, a bearing steel rod and ceramic balls. According to the diameter size of the ceramic balls to be tested, the geometric relationship of the ball-rod contact is designed and calculated, the rotating speed and the contact stress are determined; according to the selected contact stress and the fatigue cycle of the trial test, the cut-off value of the constant cut-off test is determined; the rolling contact fatigue test is carried out on the ceramic balls to be tested, and the contact fatigue performance of the ceramic balls is evaluated. The application can evaluate ceramic balls of different diameter sizes without special sample preparation, so that the ceramic balls in actual bearings can be directly tested.

The invention relates to the technical field of metal material performance evaluation, in particular to a method for predicting the contact fatigue strength of a surface modified metal material or a metal component. According to the prediction method provided by the invention, by observing and measuring the fatigue fracture and testing the hardness and residual stress of the surface modification reinforced layer, the level of the contact fatigue strength of the material can be rapidly judged, the evaluation period and the test cost are remarkably shortened, and the method has the characteristics of rapidness, high efficiency and low cost. The prediction method provided by the invention is based on the physical nature (crack initiation) of fatigue failure, the evaluation standard is combined with microstructure observation and theoretical calculation, and the prediction result is scientific, visual and reliable. According to the prediction method provided by the invention, not only can the fatigue strength be judged, but also the defects (such as whether the infiltrated layer depth and the hardness gradient are reasonable) of the surface modification process can be reversely deduced through the crack initiation position, and a clear direction is provided for optimizing the surface modification process.

A moderate-strength steel rail is provided. The chemical composition of the moderate-strength steel rail in weight percentages includes carbon 0.70-0.90 wt %, silicon 0.08-0.65 wt %, manganese 0.69-1.31 wt %, chromium 0.10-0.25 wt %, phosphorus ≤0.020 wt %, sulfur ≤0.020 wt %, and iron 96.85-98.41 wt %. According to a production method for the moderate-strength steel rail of the present invention, the moderate-strength steel rail produced has a rail hardness of 350-370 HB, a wear amount of ≤0.40 g, a contact fatigue life of ≥50,000 times, and a 610 mm steel rail waist opening ≤3.0 mm / 400 mm.

The present application provides a kind of carburized gear tooth top modification and shot peening composite strengthening method, belongs to the field of gear precision machining and manufacturing, the method is modified to the part of tooth face close to tooth top and is strengthened by secondary shot peening of different shot peening intensity to modified gear.The method specifically needs to preset a certain point of tooth surface as the starting point of tooth top modification;According to the starting point, the circular arc curve tangent to the involute of tooth surface is established as the tooth top modification curve;Establish gear load analysis model to optimize the parameters of preselected modification starting point and circular arc curve radius;According to the modification parameters of optimization design, high-precision modification processing is carried out;Shot peening is carried out on the gear after modification processing;Finally, the surface performance and fatigue performance of gear are detected.The present application can use tooth top modification and shot peening composite, composite strengthen the surface of gear, improve the performance of machined gear tooth surface, can improve the contact fatigue performance and bending fatigue performance of gear at the same time.

The application discloses a residual stress improvement method for a railway wheel, and specifically as follows: determining vibration parameters of a vibration aging treatment, including exciting force, exciting time and exciting frequency of different tread depths, and then performing the vibration aging treatment on the wheel. The residual stress improvement method based on the vibration aging treatment improves the production efficiency of the wheel, and compared with a wheel treated by a traditional quenching + tempering process, the wheel treated by the vibration aging treatment can effectively reduce the residual stress of the wheel, the shrinkage value of the wheel flame cutting is reduced by about 30%, and the mechanical properties and the contact fatigue properties can be improved.

The present application relates to line surface combined contact type wind power variable pitch slewing bearing, comprising: double half outer ring, inner ring, double row axial combined rolling unit and radial roller; The upper and lower cooperation of the double half outer ring forms a whole outer ring and is matched with the inner ring to form a bearing sleeve; The outer diameter center area of the inner ring is provided with a protruding structure extending to the inner diameter of the outer ring, the double half outer ring includes upper half outer ring and lower half outer ring, and the outer diameter protruding outer surface of the inner ring is provided with a groove structure; The upper and lower end faces of the protrusion form a space for bearing double row axial rolling unit between the inner diameter of the retaining edge of the double half outer ring, and the space for bearing radial roller is formed between the protruding groove and the corresponding inner diameter of the outer ring; The axial combined rolling unit comprises: 4 independent bodies and a plurality of cylindrical rollers; It has strong axial bearing capacity, and has strong advantages in axial adaptive inclination and anti-overturning capacity; Reduce the risk of traditional three-row cylindrical slewing bearing contact fatigue.

The present application belongs to the field of die steel heat treatment, and relates to a quenching heat treatment method for enhancing contact fatigue of die steel. The present application adopts a multi-stage heat treatment strategy, effectively improves the microstructure of the die steel, improves the uniformity and stability of the material, and maintains good toughness, and solves the problem of traditional heat treatment methods at the cost of sacrificing the internal uniformity of the material by cyclic operation of heating the die steel to phase transition temperature T1+(30-50 DEG C) and cooling to phase transition temperature T1-(30-50 DEG C).

The invention discloses a steel rail with excellent fatigue resistance and corrosion resistance and a manufacturing method thereof, and the manufacturing method comprises the following steps: S1, casting a first casting blank and a second casting blank, milling scale on the surface layer of an upper wide surface until the surface is flat, and then oppositely stacking the milled surfaces; s2, welding and sealing joints of the casting blank in a vacuum chamber through an electron beam welding machine to form a combined casting blank, and heating the combined casting blank until the combined casting blank is easy to deform; and S3, the steel rail is manufactured through cogging by a cogging mill, rough rolling by a universal rolling mill, medium rolling and finish rolling, the first casting blank is rolled into a steel rail head, the second casting blank is rolled into a rail web and a rail bottom, the steel rail head is accelerated to be cooled to 500 DEG C or below at a high cooling speed, and the rail bottom is accelerated to be cooled to the room temperature at a medium cooling speed. By adopting a railhead and rail bottom performance differential cooling strategy and a combined casting blank rolling steel rail technology, the contradiction that corrosion resistance, contact fatigue resistance, (low-temperature) toughness and plasticity, weldability and other performance are difficult to synergistically improve theoretically is solved, and the actual service performance of the steel rail is greatly improved.

The application relates to the technical field of mechanical engineering, and discloses a kind of angular contact ball bearing optimization design method, according to the load of rotor system and bearing installation structure space, the load of double half inner ring angular contact ball bearing is calculated, and the structure parameters of double half inner ring angular contact ball bearing are designed;The load actually borne by angular contact ball bearing under the working state of rotor is analyzed, the three-point contact, climbing, contact stress of rolling body and sleeve ring are calculated, the bearing structure parameters meeting the requirement of bearing steady-state performance are determined by adjustment;Then, through carrying out bearing dynamic performance analysis, according to bearing film thickness ratio and motion stability, the cage parameters or bearing roughness are optimized, so that the steady-state and transient performance of the bearing meet the design requirements.The application comprehensively considers the load transmission relationship between the bearing and the rotor, and on the basis of fully considering the change law of the dynamic performance of the bearing, such as contact fatigue, slip, three-point contact and cage motion stability, the structure parameters of the double half inner ring angular contact ball bearing are optimized.

A bearing high-temperature contact fatigue test device comprises a shell, a test bed is arranged in the middle of the shell and located at the top end of a supporting shaft, a thrust shaft is arranged below the supporting shaft, and a transmission shaft is arranged above the test bed. According to the high-temperature test device, the use requirements of equipment at the high temperature of 250 DEG C + / -5 DEG C, the load of 100-1000 kgf, the rotating speed of a main shaft of 0-2000 rpm and the adjustable speed are met, the real service state of the thrust piece in the high-temperature state is better simulated, more real test data are obtained on a testing machine, and a test basis is provided for high-temperature material selection of parts and improvement of material fatigue performance.

The anti-fatigue coating comprises a first functional layer and a second functional layer, and a tooth-shaped staggered stepped interface is arranged at the joint of the top of the first functional layer and the bottom of the second functional layer; wherein the second functional layer comprises a plurality of first sub-layers and a plurality of second sub-layers which are deposited in an overlapping manner. The tooth-shaped staggered ladder-shaped interface on the surface of the Fe-based amorphous layer and the second functional layer form an overlapped and meshed connection interface, so that the binding force of the two layers is increased to be larger than or equal to 80 N, and the contact fatigue life is prolonged to be 6000 km or above. The first sub-layer in the second functional layer is used as a hardness layer, so that abrasive wear and crushing deformation under heavy load are effectively resisted; the second sub-layer serves as a lubricating layer, the friction coefficient is low, friction loss is reduced, and lubricating oil can be stored by preparing the micro pits.

The invention discloses a production method for improving wear resistance of a pearlite steel rail. The specific production process comprises the following steps: (1) heating a steel billet; (2) rolling is conducted, specifically, the steel billet is rolled into a steel rail through a universal rolling mill, the initial rolling temperature is 1100 + / -30 DEG C, and the final rolling temperature is 925-940 DEG C; the cooling process of the steel rail is mainly divided into three stages; the pearlite rail steel comprises the following element components in percentage by mass: 0.78 to 0.80 percent of C, 0.61 to 0.71 percent of Si, 0.90 to 0.98 percent of Mn, 0.04 to 0.12 percent of V, less than or equal to 0.02 percent of P and less than or equal to 0.02 percent of S. And the balance of iron and inevitable impurities. Through the component optimization-gradient cooling-heat treatment process, on the premise that the toughness of a steel rail matrix is guaranteed, the hardness, wear resistance and contact fatigue resistance of a railhead key wear area are remarkably improved, and the service life of the steel rail is prolonged.

A method for determining the surface strengthening process of a rotating wheel is disclosed. This method involves conducting research on the surface strengthening of Cr12MoV material and utilizing QPQ technology to strengthen the surface of the rotating wheel. The strengthened rotating wheel is then applied to complex working conditions requiring high load, high wear resistance, and resistance to contact fatigue. The invention involves surface nitriding, nitrocarburizing, and composite QPQ salt bath treatment of the specimens. Based on the research results of the process parameters for these three surface strengthening methods (see Figures 3-5), the surface hardness and tribological properties of the specimens under different surface strengthening regimes are compared and analyzed. Analysis of the experimental data shows that the composite QPQ salt bath treatment exhibits the best wear resistance and meets the hardness requirements for the rotating wheel's operation. Therefore, composite QPQ salt bath treatment is determined as the method for strengthening the rotating wheel surface. Experimental verification shows that the service life of the rotating wheel strengthened by this invention is increased by 10% compared to the untreated rotating wheel.