83 results about "Surface fatigue" patented technology

A wireless, integrated, mountable, portable, battery-operated, non-contact eddy current sensor that provides similar accuracy to 1970's laboratory scale equipment (e.g., a Hewlett-Packard GP4194A Impedance Analyzer) at a fraction of the size and cost.

The laser nanometer cermet alloying process for surface of metallurgical hot roller includes the following steps: 1. machining the roller to eliminate surface fatigue layer to obtain required size and shape, grinding the surface to be laser treated, eliminate dirt and cleaning properly; 2. mixing phenolic resin adhesive and nanometer carbide ceramic paint homogeneously and coating the mixture to the surface of the roller in the thickness of 0.01-0.05 mm before air drying; and 3. scanning the nanometer ceramic coating on the surface of the roller fast with high power CO2 laser in the technological parameters of laser power 1,000-10,000 W, scanning speed of 1.5-20 m/min, lapping rate of 15-35 % and light spot diameter of 0.6-5 mm. The present invention has optimized technological parameters, and can result in solid solution reinforcing and dispersion reinforcing effect, raise the heat stability of the alloy layer, and raise the strength, plasticity and toughness of the alloy layer.

The invention belongs to the field of laser repairing and particularly relates to a technique for restoring the precision of a stepped cushion of a rolling mill by adopting a laser cladding technology. The technique is specifically implemented by the following steps of: surface derusting, detection before repair, processing for removing surface fatigue layers, detection after processing, determination of a laser cladding process (including technological parameters and alloy powder constituents), detection after laser cladding, rough and fine machining, and detection after repair; the techniqueis simple and convenient to operate, greatly alleviates the labor intensity, has the characteristics of restoring the dimensional precision of the original design and improving the corrosion resistance and the wear resistance of the surface, improves the overall use efficiency, has quite small influences on the surface and prevents relatively large deformation; after being machined by a grindingmachine, the surface is smooth, uniform and high in glossiness; after repairing, a product is tracked and detected; the dimensional precision of the stepped cushion can be restored after laser cladding; the running cost is low; the surface is free of detection flaws and cracks after being machined; the product can meet the requirements of normal use; and the service life of the product is prolonged by at least three times.

The invention discloses a method for repairing a roller sleeve of a continuous casting roller. The method comprises the following steps of: preliminarily checking the roller sleeve; measuring the size of each part of the roller sleeve, removing a fatigue layer on the surface of the roller sleeve, and performing magnetic particle inspection and ultrasonic flaw detection; preparing Ni45 and WC alloy powder by adopting a mechanical mixing method, preheating the roller sleeve, coating the alloy powder on the surface of the roller sleeve by adopting a coaxial powder feeding method and scanning with a high-power CO2 laser device, thermally treating the whole roller sleeve, and slowly cooling together with a furnace; and performing rough machining and precision machining on the roller sleeve of the continuous casting roller meeting the requirements by using a lathe. Compared with the prior art, the method has the advantages that the service life of the roller sleeve is prolonged; consumption is reduced; the roller sleeve is high in abrasion resistance and heat resistance; and the method is simple, strong in controllability and low in cost, and saves the alloy material.

High-strength bainitic steel rails have improved resistances to surface fatigue failures and wear required of the head of rails for heavy-load service railroads. The high-strength bainitic steels rails having excellent resistances to surface fatigue failures and wear contain constituents of specific ranges and consisting of bainitic structures at least in part are characterized in that the total area occupied by carbides whose longer axes are 100 to 1000 nm in a given cross section of said bainitic structures accounts for 10 to 50 percent thereof.

There is a method for modeling the surface fatigue life of a mechanical component. The method has the following steps: a) modeling the surface fatigue life of the mechanical component on an atomistic scale to form an atomistic model, b) modeling the surface fatigue life of the mechanical component on a mesoscale to form a mesoscale model, c) modeling the surface fatigue life of the mechanical component on a macroscale to form a macroscale model, and d) testing the surface fatigue life of the mechanical component. Feedback from the macroscale model is employed at least once to validate the atomistic model. Feedback from the macroscale model is employed at least once to validate the mesoscale model. Feedback from the testing is employed at least once to validate the macroscale model. There is also an interactive, multiscale model for prediction surface fatigue life or degradation rate for a mechanical component.

The invention relates to a laser rapid repairing method for high chromium cast steel roller surface layer fatigue micro cracks. The laser rapid repairing method is used for rapidly conducting laser repairing on high chromium cast steel roller surface layer fatigue micro cracks in order to obtain a corrosion-resistant and high-temperature-corrosion-resistant surface reinforced layer. The laser rapid repairing method is characterized by comprising the steps that (1) surface preprocessing is carried out a high chromium cast steel sample with surface fatigue micro cracks, the high chromium cast steel sample is preheated to 150 DEG C, and the temperature is kept for 1.5 h; (2) the diameter of a laser spot is 3-5.5 mm, the power is 1800-2700 W, the scanning speed is 300-1500 mm/min, the overlap rate is 16.7-50 %, and argon is used as protective gas; (3) two times of tempering at 560 DEG C are carried out after laser processing, and the temperature keeping time is 1 h every time; (4) the initial point and the finishing point in the laser fusing process do not fall on a workpiece. The laser rapid repairing method can fuse high chromium cast steel roller surface layer fatigue micro cracks, a laser fusing layer and a base body are combined in a metallurgy mode, the thickness is 0.4-0.7 mm, the hardness is improved to HV672, the corrosion resistance is improved by three times compared with the base body, and the high temperature abrasion resistance at 560 DEG C and 650 DEG C is obviously improved compared with the base body.

A method for restoring the inner bore of a gear coupling is disclosed. Dimensions of all parts of the gear coupling are measured to check whether all the dimensions satisfy laser coating restoration standards, the surface fatigue layer of the inner bore of the gear coupling is removed, Ni55 and nanometer WC powder which are prepared in proportion are fully mixed in a mechanical powder mixer through adopting a mechanical mixing method, the Ni55 and the nanometer WC powder are coated on the surface of the inner bore of the gear coupling through adopting a coaxial powder sending method and through scanning by adopting a large-power CO2 laser, and the gear coupling undergoes heat treatment and then is slowly cooled with a furnace; and the inner bore of the cooled gear coupling is machined to obtain the gear coupling with the dimensions and the surface process which satisfy requirements, the gear coupling undergoes processing precision detection, and finally the gear coupling is packaged. Compared with the prior art, the method disclosed in the invention has the advantages of continuous use, better performances and long service life of the gear coupling, simple technology, strong controllability, less energy consumption and the like.

This invention discloses a process for laser surface enhancement of roller for rolling profiles. The process comprises: processing the roller by turning to remove the surface fatigue layer, inspecting damage, pretreating the surface, loading into a laser processing machine tool, uniformly spraying light-absorption material onto the roller body by a spray gun to completely coate the sites to be processed, drying the light-absorption material, and performing enhancement treatment by selecting laser intensity indexes. The enhancing layer of the treated roller has a thickness of 0.8-1.5 mm, and hardness in HRC 47-53 range. The enhancing layer does not produce any crack. The treated roller does not deform, and the surface roughness can satisfy machining requirements. The treated roller has good toughness and good anti-fatigue ability.

The invention discloses a metal surface fatigue detecting system and a metal surface fatigue detecting method for an off-shored crane. The detecting system comprises a plurality of strain sensors and a detecting computer, wherein the plurality of strain sensors are arranged at a plurality of preset positions of the off-shored crane to detect stress data of each preset position of the off-shored crane under different working conditions; the detecting computer comprises a computing device and a display device; the display device is connected to the plurality of the strain sensors to receive the stress data for generating a variation image of the stress data and judging fatigue degree according to a preset model; and the display device is connected to the computing device for displaying the variation image and the judged results of the fatigue degree. According to the scheme, the off-shored crane realizes real-time detection display of the stress data, and guarantees fatigue degree detection and fault early warning in an operation process of the off-shored crane.

The invention relates to a laser melting quenching process capable of greatly increasing the RuT300 surface hardness. The laser melting quenching process is characterized by comprising the following steps of carrying out flattening treatment and surface pretreatment on the surface of a to-be-treated RuT300 workpiece, setting the included angle of the transmitting direction of a laser beam and the normal of the treated surface of the workpiece at 0-45 DEG, carrying out laser melting quenching and carrying out liquid penetrant test immediately after the workpiece is cooled to the room temperature after the laser melting quenching. Compared with the prior art, the process disclosed by the invention has advantages that the operation is simple, the efficiency is high and the corresponding surface blackening treatment is not needed, so that the processing efficiency is increased; the workpiece deformation is little, so that the application of high-precision parts or dies can be satisfied; and the repeatability is good, the crater crack problem is well solved and a laser quenching zone with no crack or air hole on the surface is obtained, so that the surface fatigue resistance of the parts can be greatly increased and the service life of the parts is prolonged.

The invention relates to a heat treatment technology for a bearing ferrule. The heat treatment technology comprises the following steps: carrying out spheroidizing annealing on the bearing ferrule firstly, rising the temperature in a furnace to 780-810 DEG C, keeping the temperature for 3-6h, annealing the bearing ferrule, then keeping the temperature for 4-6h at the temperature of 680-720 DEG C, furnace cooling the bearing ferrule to 600-650 DEG C at the cooling speed of 20-40 DEG C/h, and tapping and air cooling the bearing ferrule; then quenching the bearing ferrule, adopting the temperature of 830-850 DEG C, keeping the temperature for 15-45min, carrying out a salt bath on the bearing ferrule at the temperature of 150-170 DEG C, carrying out isothermal holding for 60-80min, and then taking out the bearing ferrule, and air cooling the bearing ferrule to the room temperature; and finally, carrying out tempering on the bearing ferrule, air cooling the bearing ferrule to the room temperature, and carrying out tempering for 5-8h at the temperature of 150-180 DEG C. According to the heat treatment technology, the content of retained austenite in the bearing ferrule can be stabilized between 10-15 percent, so that the stability of the retained austenite is greatly strengthened; the retained austenite on the surface of a bearing can carry out inducible martensitic transformation in the very short using process from the start, so that the heat treatment technology has the advantages of good size stability, good abrasion resistance and good surface fatigue strength.

A method for detecting fatigue crack of closed surface includes emitting ultrasonic wave towards end surface vertical to roller neck to carry out detection on defects of shafts, using probe with small diffusion angle and excellent directional property to receive detection signal and displaying it on screen of crack detector, obtaining position and equivalent size of defect according to echo signal.

The invention discloses a method and a device for processing a bearing of a screw drill. The method adopts cold-rolling technique to process, firstly, an external sleeve blank or an internal sleeve blank of the bearing are processed; then the bearing of the screw drill is coldly rolled; a hydraulic oil cylinder (1) pushes a rolling wheel (7) to move downwards to be contacted with the bearing blank arranged on a rolling core roller (10) by pressurizing, thus lead the rolling wheel (7) to be parallel with the central shaft of the rolling core roller (10) and lead the rolling core roller to be contacted with the drive wheel (12) of a rotating mechanism; a coupler (14) connected with a motor (16) by a reducer drives the drive wheel and a driven wheel (13) to lead the rolling core roller to rotate; the rolling wheel (7) continuously puts pressure on the bearing blank until the bearing blank is deformed to achieve workpiece shaping standard. The invention can remarkably improve the surface fatigue intensity of a part, can eliminate a lathe machining process and can lead the utilization rate of materials to be improved from the former 45 percent to over 75 percent, which leads the power consumption of the device to be greatly reduced.

The present invention provides a steel product for gas carburizing used for manufacturing a carburized steel part. In the above steel product for gas carburizing, a composition of a base metal contains, in mass %, C: 0.1 to 0.4%, Si: exceeding 1.2 to 4.0%, Mn: 0.2 to 3.0%, Cr: 0.5 to 5.0%, Al: 0.005 to 0.1%, S: 0.001 to 0.3%, N: 0.003 to 0.03%, and O: limited to 0.0050% or less, and P: limited to 0.025% or less, and when the contents of Si, Mn, and Cr (mass %) are set to [Si %], [Mn %], and [Cr %], Expression (1) below is satisfied, and an alloy shortage layer satisfying Expression (2) below exists in a range from its surface to 2 to 50 μm in depth.

32≧3.5[Si %]+[Mn %]+3[Cr %]>9  (1)

3.5[Si %]+[Mn %]+3[Cr %]≦9  (2)

The invention provides a method for ultrasonic inclusion detection of train wheels. The method is applied to the technical fields of train wheel manufacturing and performance detecting processes. Themethod comprises the following steps: (1) performing ultrasonic flaw detection on a rim inner side surface and a rim tread of a train wheel, and determining that a detection surface with a strong defect reflection signal is parallel to a length direction of an inclusion; (2) cutting a cross section sample of a rim which contains the inclusion, and taking a sample square rod by linear cutting, wherein the inclusion exists in the middle of the sample square rod; (3) by taking the sample square rod as a sample, performing micro-particle shot blasting on the sample; and (4) applying a stair load fatigue test on the sample, wherein an initial load is lower than a fatigue limit of surface fatigue, and under a load load, ensuring that a fatigue crack cracks and expands from the inclusion. The method provided by the invention can completely display the full view of the inclusion which is discovered by ultrasonic flaw detection and can accurately measure the size of a defect.

The invention relates to a stress intensity factor-based method for estimating the fatigue damage degree of a subsurface of a bearing roller path. The method comprises the following steps of: S1. constructing a bearing model containing a material defect, and dividing a grid; S2. calculating a crack top stress intensity factor; S3. calculating an equivalent stress intensity factor; S4. determining a key hertz contact position; S5. determining a key depth of the material defect on the subsurface of the roller path; S6. determining KI (gamma), KII (gamma) and KIII (gamma) and the equivalent stress intensity factor Keff when H is equal to H0 and theta is equal to theta0; and S7. determining the crack growth rate or the crack growth angle. The method has the advantages of high efficiency, low cost, high practicability and the like based on a finite element analysis method; furthermore, by the method, the consumed time is short; the method can be combined with a test method, and a test can be instructed; and the test cost can be saved.

The invention relates to a method and device for detecting a sample axle through ultrasonic. The method comprises the steps that by means of a detected sample axle, a sensitivity compensation value which is discrepant with an axle of a physical locomotive vehicle to be maintained is obtained, correction is conducted on an ultrasonic fault detector, and the situation that defects of fatigue cracks of a wheel seat part, an axle journal part and a gear seat part of the axle of the locomotive vehicle can be rapidly and accurately detected by adopting an ultrasonic technology under the condition that a wheel set of a locomotive under repairing is not disassembled is achieved. When the axles of a large number of locomotive vehicles under repairing need to be detected on the surface fatigue cracks through the ultrasonic technology, the axles of the locomotive vehicles under repairing can be detected correspondingly on the premise of not being disassembled. By means of the method for detecting the sample axle through the ultrasonic, the detection result is accurate and reliable, detection can be achieved without disassembling the wheel set, therefore, the detection efficiency is greatly improved, and meanwhile the detection cost is reduced.

A steel for nitriding having a chemical composition consisting of, by mass percent, C: 0.07-0.14%, Si: 0.10-0.30%, Mn: 0.4-1.0%, S: 0.005-0.030%, Cr: 1.0-1.5%, Mo: ≦0.05% (including 0%), Al: 0.010% or more to less than 0.10%, V: 0.10-0.25%, optionally at least one element selected from Cu: ≦0.30% and Ni: ≦0.25% [0.61Mn+1.11Cr+0.35Mo+0.47≦2.30], and the balance of Fe and impurities. P, N, Ti and O among the impurities are P: ≦0.030%, N: ≦0.008%, Ti: ≦0.005%, and O: ≦0.0030%. The steel is easily subjected to cutting before nitriding and suitable for use as an automobile ring gear. The nitrided component having a surface hardness of 650-900 HV, core hardness being ≧150 HV, and effective case depth of ≧0.15 mm has excellent bending fatigue strength and surface fatigue strength although the content of Mo is as low as ≦0.05% and has a small amount of expansion caused by nitriding.

The invention discloses a flexible film laser cladding reinforcing method of a die-casting die. The method includes the steps that the die-casting die is detected comprehensively, and the abrasion loss of the die is determined; a surface fatigue wear layer is removed, and machining surface impurities are removed; alloy powder is prepared, the alloy powder is prearranged on the surface of the to-be-clad die-casting die, a prearranged flexible film is scanned through a laser, and a wearproof laser cladding layer is prepared; and the surface of the cladding layer is nondestructively detected, andthe cladding layer is ground and polished. By means of the method, the utilization rate of the powder in the cladding process is increased, it is guaranteed that the powder is uniformly conveyed, thereinforcing cost is reduced, and the service life of the repaired die-casting die is prolonged by one time or above compared with a conventional repairing method.

The invention relates to a rolling contact fatigue testing machine, and the machine is mainly used to carry out rapid fatigue test on rolling contact in the plane strain state. The fatigue testing machine can effectively simulate fatigue of a component with plane-strain rolling contact feature and evaluate and select processing parameters for forming the rolling contact surface, and is thus an ideal testing machine to research on the surface fatigue failure mechanism of materials. The fatigue testing machine is composed of a frame body, a linear guide rail, a sliding platform, linear motors, a loading platform and a loading mechanism, multiple strip-shaped samples can be placed on the sliding platform on the linear guide rail, and one or multiple cylindrical rolling bodies is/are arranged in the lower portion of the loading platform correspondingly. During test, the loading mechanism enables the samples make contact with the rolling bodies in certain pressure, the linear motors drive the sliding platform to make reciprocating movement in certain amplitude, and the fatigue condition of the samples can be observed after certain period.

The invention relates to the technical field of compositions, in particular to a composition for resisting sports fatigue and accelerating fatigue recovery and a preparation method of the composition.Aiming at four basic processes in sports, a human body mechanism is analyzed, and on the basis of human body changes, sea cucumber polypeptides, carnosine and oat beta-glucan are adopted as raw materials for targeted and ordered conditioning in three aspects including internal nutrient supplementing, eliminating of oxygen free radicals generated in lipid peroxidation reaction caused by fatigue and maintaining of cell pH physiological level, so that fatigue can be alleviated and eliminated substantially. Compared with the prior art in which surface fatigue is alleviated only through supplementing of body energy consumption, the composition has advantages of high safety and effectiveness.