95 results about "Fatigue limit" patented technology

The invention discloses a method and device for predicting the fatigue life of a high-temperature alloy vacuum electron beam welding structure, and belongs to the technical field of aero-engines. The method comprises the following steps: acquiring fatigue experiment data of a target high-temperature alloy standard sample; extracting the maximum area of an initial defect, a defect shape factor and crack source position information; obtaining a stress intensity factor range considering defect morphological characteristics and a fatigue crack propagation threshold value of a material structure containing initial defects, and correcting a damage tolerance theoretical formula to obtain simulation data; fatigue test data and simulation data are fused to form an initial data set, a fatigue limit is calculated and expanded to the data set, the expanded data set serves as input, training is conducted through a support vector regression method, hyper-parameters are determined through Bayesian optimization, and a fatigue life prediction result of the high-temperature alloy vacuum electron beam welding structure is output. The method provided by the invention can well consider the influence of different morphology defects on the fatigue performance of the welded joint.

The invention relates to a fatigue limit rapid prediction method based on infrared thermal image energy dissipation characteristics. The method comprises the steps of sample preparation and pretreatment, fatigue loading stress level upper limit determination, infrared fatigue test and temperature rise data acquisition, thermal image data processing and temperature rise feature extraction, energy dissipation model construction, fatigue limit value prediction, error analysis and method verification. The method comprises the following steps: monitoring steady-state temperature rise rates under different stresses through a thermal infrared imager, establishing a relation curve between a dissipation rate and a stress amplitude, predicting a fatigue limit based on a least square method, and comparing the fatigue limit with an S-N test result for verification. Compared with a traditional method, the method has the advantages of high prediction precision, high response sensitivity, low loss, short test period and the like, and is particularly suitable for rapid fatigue limit prediction and strengthening effect judgment of the high-temperature alloy material subjected to laser-assisted ultrasonic rolling strengthening.

The invention discloses a method for cooperatively regulating and controlling the microstructure and fatigue resistance of a GH4169 alloy based on LPBF, and belongs to the field of metal additive manufacturing. Through multi-dimensional collaborative innovation such as LaZrO core-shell nano-composite strengthening phase design, dynamic energy input and intelligent regulation and control, grain boundary engineering and precipitated phase collaborative optimization and graded green post-treatment, the problems that when a GH4169 alloy part is prepared through a traditional LPBF technology, grains are coarse and large, the number of internal defects is large, and the fatigue performance is insufficient are solved. The breakthrough achievements that isometric crystals are ultra-refined (3-10 microns), the defect rate is reduced by more than 50% and the room-temperature high-cycle fatigue limit is improved by 38% are achieved, meanwhile, the green manufacturing requirement is met, and a high-performance and high-reliability complex part manufacturing solution is provided for the fields of aerospace and the like.

The invention provides an additive repair blade high-cycle fatigue limit prediction method based on random defect probability distribution, and relates to the field of aero-engine fan and compressor blade maintenance, and the method comprises the steps: obtaining the defect distribution of a real blade; establishing a prediction model based on a critical distance theory; according to the prediction model, critical distances of the multiple real blades are determined, and a first critical distance is generated; performing defect reconstruction based on the defect distribution of the real blade to generate a virtual blade; obtaining the first high-cycle fatigue strength of the virtual blade according to the defect distribution of the virtual blade, the first critical distance and the prediction model; respectively determining a plurality of defect parameters and a Pearson coefficient of the first high-cycle fatigue strength, and screening a first parameter significantly related to the first high-cycle fatigue strength; constructing a fatigue strength evaluation model; and inputting the first parameter into the trained fatigue strength evaluation model, and outputting the predicted high-cycle fatigue strength. According to the scheme, the high-cycle fatigue limit of the blade can be quickly predicted, and the prediction accuracy is improved.

The invention discloses a method for rapidly measuring the fatigue limit of a composite material through an infrared thermography method, and belongs to the technical field of composite material inspection. According to the method, the problems that an existing method lacks definite physical significance and obvious temperature rise is difficult to detect are solved, the temperature change of the surface of the composite material is captured through the thermal infrared imager, the relation between the temperature change and the stress level is analyzed, and the dissipation mechanism of the composite material in the elastic stage and the plastic stage can be effectively distinguished; the fatigue limit of the material can be quantitatively determined through linear fitting and intersection calculation by taking the elastic limit as a boundary and combining an inherent dissipation theory and a fatigue damage mechanism, so that inflection point determination has clear physical significance, and the fatigue limit can be accurately determined in a short time; in addition, by means of the non-contact characteristic of the method, physical damage to the samples is reduced, the repeatability and reliability of the experiment are improved, meanwhile, the number of the samples is reduced, the experiment time is shortened, and the experiment cost and time are reduced.

Disclosed are a wire rod and a steel wire for a spring, a spring with improved strength and fatigue limit, and a method for manufacturing the same. The disclosed wire rod for a spring with improved strength and fatigue limit according to an embodiment includes, in percent by weight (wt%): 0.6 to 0.7% of C, 2.0 to 2.5% of Si, 0.2 to 0.7% of Mn, 0.9 to 1.5% of Cr, 0.015% or less of P, 0.01% or less of S, 0.01% or less of Al, 0.01% or less of N, 0.25% or less of Mo, 0.25% or less of W, 0.05% to 0.2% of V, 0.05% or less of Nb, and the balance of Fe and unavoidable impurities, wherein Mn+Cr≤1.8% and 0.05 at%≤Mo+W≤0.15 at% may be satisfied.

The application provides an aero-engine blade high-cycle fatigue limit prediction method, first, parameters of a blade subjected to impact-corrosion coupling damage are measured, a fractal dimension and a stress concentration coefficient are calculated, the equivalent stress is corrected by using the fractal dimension and the stress concentration coefficient, a corrected critical distance model is obtained, and the fatigue limit of the blade subjected to coupling damage is predicted and calculated by using the corrected critical distance model. The blade high-cycle fatigue limit prediction method provided by the application innovatively integrates the three-dimensional fractal dimension, the theoretical stress concentration coefficient and the stress gradient distribution function near the notch root into the same model, and the blade fatigue limit obtained by the prediction calculation is highly consistent with the measured value of the test.

The application provides an aero-engine blade fatigue failure analysis method, first, the foreign object damage morphology data of the real blade is collected to form a real blade database, then the design parameters of the simulation blade are obtained according to the morphology and stress distribution of the real blade, and then the finite element model of the simulation blade is established, the modal calculation is carried out, whether the inherent frequency of each order mode meets the set requirement is verified, if the set requirement is met, the foreign object damage simulation of the finite element model of the simulation blade is carried out, the simulation result is obtained, and the consistency verification is carried out with the real blade database, finally, the real model of the simulation blade is made, the FOD test and the HCF test are continuously carried out on the real model of the simulation blade, and the fatigue limit of the real model of the simulation blade after damage is obtained. The method takes the foreign object damage morphology data of the real blade as the reference, realizes the high-cycle fatigue limit test of the foreign object damage simulation blade which is closer to the real working condition, has low cost, high controllability of parameters, and good interpretability.

This invention provides a novel vibration fatigue testing method for gas turbine blades. Addressing the problems of large specimen wear, long testing time, and limited results associated with traditional step-and-step stress loading methods for obtaining blade fatigue limits, this invention excites blade resonance on an electromagnetic vibration table using novel step-and-step stress loading techniques on identical blade specimens. While retaining the step-and-step matching standard, when limited test data cannot meet the matching requirements, a stress "concession" method is rationally applied based on the turbine blade structure and fatigue strength level to eliminate test data with significant stress deviations, thereby obtaining the median fatigue strength of blades from the same batch. This invention makes stress matching faster and more flexible, requiring only 2-3 stress levels to achieve a test fitting result with a confidence level of over 95%, demonstrating high accuracy. This method is applicable to fatigue limit tests of all gas turbine blades.

The invention discloses a casting molding method for an aluminum piston side drainage runner of a large combustion chamber of an engine, and relates to the technical field of engine piston manufacturing. According to the casting forming method for the aluminum piston side drainage runner of the large combustion chamber of the engine, silicon is added to form an eutectic silicon network, the liquidity of molten aluminum is improved, the grain size is refined, copper and magnesium are added to improve the tensile strength, nickel is matched to inhibit high-temperature creep, the casting speed and the casting pressure are controlled at different casting stages, and the casting quality is guaranteed; in the casting process, ultrasonic vibration is carried out, grains are further refined, semi-solid feeding is promoted, a rotating magnetic field drives casting liquid to carry out spiral mold filling, the gas entrapment tendency is reduced, axial flowing of the casting liquid is promoted, turbulent flow is reduced, the grain size is refined in cooperation with a pulsed electric field, the microshrinkage porosity of the root of a runner is reduced, and the fatigue limit of the root of the runner is improved; the heat resistance, wear resistance and thermal fatigue resistance of the piston are improved, so that the performance of the piston is optimized to prolong the service life of the piston.

The invention relates to the technical field of fatigue testing, and discloses a fatigue experiment device for axle production, which comprises two racks, an annular chain conveying piece is arranged between the two racks, lifting cushion tables are arranged on the surface of the annular chain conveying piece in an array manner, a supporting assembly is slidably connected to the racks, and the supporting assembly is provided with a plurality of clamping grooves. An intermittent rotating assembly is fixedly installed at the right end of the annular chain conveying piece, a reciprocating moving assembly is arranged between the left side of the intermittent rotating assembly and the supporting assembly, an arch-shaped frame is fixedly installed between the tops of the two racks, and two axle suspension assemblies are fixedly installed on the top wall of the arch-shaped frame. The sliding frame is stably supported through the wave part, the cushion platform body is prevented from falling during wheel collision, a firm bumpy road surface is simulated, and therefore the chain body rotates anticlockwise, the relative positions of the wave part and the axle are continuously switched, the bumpy road surface is continuously simulated, long-time detection of the axle is facilitated, and the fatigue limit of the axle is conveniently measured.

The present invention provides a method for preparing a high-modulus, high-strength, and high-fatigue-resistant aluminum-based composite sheet. The method comprises subjecting an in-situ ceramic particle-reinforced aluminum-based composite material to a sequential semi-continuous casting, hot rolling, cold rolling, solution treatment, cold rolling, and aging treatment. The method for preparing the aluminum-based composite sheet provided by the present invention features a simple and rational process. The non-uniform distribution of in-situ ceramic particles forms a two-stage heterogeneous structure with a non-uniform grain distribution, achieving a multi-layered reinforcement structure and a microstructure that inhibits fatigue crack propagation. This method simultaneously improves the elastic modulus, tensile strength, fatigue limit strength, and fatigue crack propagation resistance of the aluminum-based composite sheet, and can be industrially produced using existing industrial equipment.

The application discloses a valve box processing method, comprising the following steps: S1, rough machining of a pressure pump valve box forge blank; S2, normalizing treatment; S3, first tempering treatment; S4, carbonitriding treatment; S5, precooling quenching treatment; S6, second tempering treatment; and S7, packaging. The application simultaneously permeates carbon and nitrogen into the workpiece in the form of carbonitriding to form a carbonitriding layer, on the one hand, carbon atoms enter the metal surface and combine with metal atoms to form carbide, thereby improving the hardness and wear resistance of the workpiece surface, and wear and scratches on the metal surface can be effectively prevented; on the other hand, the permeation of nitrogen forms a dense nitride layer on the workpiece surface, improves the corrosion resistance, and enables the workpiece to be applicable to a harsh environment during oil exploitation; and on the third aspect, the residual compressive stress of the carbonitriding layer can improve the fatigue limit of the workpiece, thereby improving the fatigue strength of the workpiece and reducing brittleness.

The present invention relates to a step cyclic loading rejuvenation method for bulk metallic glasses, comprising the following steps: 1) processing the metallic glass into a specimen capable of cyclic loading treatment; 2) installing the specimen on a cyclic loading device and performing step cyclic loading treatment with an alternating load. The step cyclic loading treatment starts from an initial stress amplitude lower than the fatigue limit, and after a certain number of cyclic loading times, the step stress amplitude is increased for cyclic loading until before the specimen fractures. Compared with the prior art, the method of the present invention has high efficiency, simple process and strong universality, and has good application prospects for regulating the energy state and properties of the structure of metallic glasses.

The invention provides a gas turbine compressor blade service life evaluation method based on high-cycle fatigue characteristics, and aims to solve the problem that fatigue tests under pure simulation and laboratory conditions cannot be effectively combined to meet the requirement of gas turbine blade type core component service life evaluation. According to the method, the strength condition and the vibration condition of the blade are determined through finite element analysis, then the stable attenuation law of the fatigue strength of the blade is obtained by actually measuring the vibration stress and the fatigue limit values of the blade in different use time periods, and the service life of the gas turbine compressor blade is comprehensively evaluated by taking the high-cycle vibration fatigue reserve as the standard. The method is not limited to a ship gas turbine compressor, is also suitable for effective evaluation of the service life of the moving blades of an industrial gas turbine and an aero-engine compressor, and can provide a fatigue reliability design direction for a new model.

The invention discloses a high-fatigue TC4 titanium alloy fine-grain bar for a blade and a preparation method of the high-fatigue TC4 titanium alloy fine-grain bar, and belongs to the technical field of titanium alloy machining. According to the method, firstly, a qualified TC4 titanium alloy cast ingot is obtained through three times of VAR smelting; secondly, the cast ingot is subjected to upsetting and drawing forging at the upper and lower heating numbers at the phase transformation point to obtain a middle bar blank A; then the intermediate bar blank A is subjected to short-time-space water boiling cold and heat treatment above the phase transformation point, and an intermediate bar blank B is obtained; performing low-temperature rolling on the intermediate bar billet B to obtain an intermediate bar billet C; then carrying out medium-high temperature finish machining on the intermediate bar billet C to obtain a target bar billet D; and finally, surface defects and oxide skin of the target bar blank D are removed, the high-fatigue TC4 titanium alloy fine-grain bar for the blade is obtained, and the bar has high-temperature strength and heat stability while the excellent fatigue performance (the room-temperature smooth high-cycle fatigue cycle number is larger than 1.0 * 10 < 7 > times, and the fatigue limit is larger than or equal to 600 MPa) is guaranteed.

The invention relates to a high-reliability gear fatigue limit rapid test method based on a reliability conversion coefficient, and the method specifically comprises the steps: carrying out a gear fatigue strength lifting method test, and obtaining the reliability conversion coefficient based on a mathematical statistical method; carrying out a Locati method fatigue test to obtain a fatigue test point; processing a test result of the Locati method based on a reference fatigue S-N curve, and obtaining a gear fatigue limit under 50% reliability; and according to the gear fatigue limit under the reliability of 50%, evaluating the gear fatigue limit under the high reliability by applying the reliability conversion coefficient. The problems of large test sample size, high cost and long test period required for obtaining the high-reliability gear fatigue limit are solved, and a high-precision evaluation result can be kept while the test quantity is reduced; the method can be conveniently applied to engineering practice, and efficient method support is provided for gear anti-fatigue and high-power-density design.

This application provides a method and system for predicting the fatigue performance of composite materials based on infrared thermal imaging, belonging to the field of material mechanical property testing technology. The method includes determining the fatigue performance characterization parameters and corresponding static strength values ​​of the composite material to be predicted; constructing a fatigue performance testing system for the composite material; determining the progressively increasing fatigue loading stress and load; applying progressively increasing stress levels of fatigue cyclic loading to the composite material under a given cycle to obtain a temperature field sequence and extracting temperature characteristic parameters characterizing the material's energy dissipation state; based on the temperature characteristic parameters and a composite material damage infrared characteristic library, obtaining the temperature-damage characteristic-stress relationship of the composite material under each cyclic loading level; based on this relationship, obtaining the critical transformation stress of the composite material to be predicted, determining the fatigue limit, and obtaining the fatigue life-stress relationship for fatigue performance prediction. This scheme improves prediction efficiency and accuracy, and avoids misjudgment based on a single parameter.

The invention discloses a Bayesian probability fatigue strength evaluation method for a structural member with defects, and relates to the technical field of fatigue strength prediction of aerospace metal structural members. The method comprises the following steps: firstly, drawing a fatigue limit curve based on test data of a defective material sample, embedding a physical rule of an El Hadad curve through a synthetic data set, and establishing physical priori knowledge of a defect size and a fatigue strength behavior; training model parameters by using test data of the structural member, constructing a Bernoulli likelihood function, and matching an actual failure tag of the structural member; and finally, fusing the prior distribution and the likelihood function through the Bayesian theorem to obtain probability distribution after parameter updating, and outputting a predicted failure probability expected value and uncertainty. According to the method, material sample data containing defects are fused as physical prior based on the Bayesian theory, and the probability fatigue strength is evaluated through experimental data of a small amount of structural parts.

The invention discloses a rapid optimization design method and device for inherent frequency, buckling pressure, maximum stress and other key indexes of an elastic strip, and belongs to the technical field of rail fasteners. Comprising the following steps: acquiring a plurality of key parameters of the elastic strip, including buckling end contact rigidity, tail end contact rigidity, buckling limb length, buckling end arc radius, tail end arc radius and side limb arch height; adjusting at least one key parameter based on the established quantitative relationship between the parameters and the inherent frequency, buckling pressure and maximum stress of the elastic strip; and calculating the adjusted key indexes, and optimizing the key indexes until a preset target is met. According to the method, the influence rule of key parameters on various performance indexes, namely collaborative optimization design of the missile strip, is defined, so that the inherent frequency of the missile strip can be remarkably improved to avoid a resonance area on the premise of keeping compatibility with an existing fastener system, meanwhile, the working stress is controlled below the fatigue limit, enough fastening force is ensured, and the service life of the missile strip is prolonged. And the resonance fatigue fracture problem of the elastic strip is fundamentally solved.

The present invention provides a wire rod, steel wire, and spring which are excellent in strength and workability, can be easily nitrided even at high temperatures, and have improved nitriding properties and fatigue limit, and a manufacturing method thereof. [Solution] The alloy is composed of, by weight percent, C: 0.6-0.7%, Si: 2.0-2.5%, Mn: 0.2-0.7%, Cr: 0.9-1.5%, P: 0.015% or less, S: 0.01% or less, Al: 0.01% or less, N: 0.01% or less, Mo: 0.25% or less, W: 0.25% or less, V: 0.05%-0.2% or less, Nb: 0.05% or less, with the remainder being Fe and other unavoidable impurities, Mn+Cr≦1.8%, 0.05at%≦Mo+W≦0.15at%, and 1mm in the center of a cross section perpendicular to the length direction 2 The alloy is characterized in that the ratio of the area that satisfies one or more of C>0.85%, Si>3.0%, Mn>0.8%, and Cr>2.0% by weight is 10% or less.

The present application relates to a kind of fatigue limit fast prediction method based on infrared thermal image energy dissipation characteristics, containing sample preparation and pretreatment, fatigue loading stress level upper limit determination, infrared fatigue test and temperature rise data acquisition, thermal image data processing and temperature rise feature extraction, energy dissipation model construction, fatigue limit value prediction, error analysis and method verification.Steady temperature rise rate under different stresses is monitored by infrared thermal imager, the relationship curve of dissipation rate and stress amplitude is established, the fatigue limit is predicted based on least square method, and compared with S N Test results are compared and verified.Compared with traditional method, the method has the advantages of high prediction accuracy, high response sensitivity, low loss, short test cycle, etc., and is especially suitable for fatigue limit fast prediction and strengthening effect determination of high-temperature alloy material after laser-assisted ultrasonic roll strengthening.​

The application provides a turbine blade root extension vibration fatigue test piece and a construction method thereof. The method comprises the following steps: obtaining a real turbine blade, wherein the real turbine blade comprises a blade body, a root extension and a tenon; cutting the blade body of the real turbine blade to form a partial blade body, and cutting the tenon of the real turbine blade to form a complete root extension and a partial tenon; the cutting positions of the blade body and the tenon of the real turbine blade are such that the bending section modulus of the root extension position is the lowest, and the first-order natural frequency of the turbine blade after cutting is the same as or similar to that of the real turbine blade; machining a fixed clamping end head; and fixing the fixed clamping end head to the tenon position after cutting, thereby forming the turbine blade root extension vibration fatigue test piece. The method provided by the application can accurately obtain the fatigue limit data of the root extension position of the turbine blade.

The invention belongs to the technical field of aeronautical materials, and particularly relates to an aeronautical high-conductivity ultrahigh-strength aluminum alloy material and a preparation method thereof. Through the Zr-Er-Y multi-element microalloying synergistic effect, a coherent Al3 (Zr, Er and Y) nano dispersed phase is formed, grains are remarkably refined, recrystallization is inhibited, meanwhile, the Y element optimizes the grain boundary precipitated phase form, the grain boundary binding force is improved, and a structure foundation is laid for high toughness of the alloy. A cooperative treatment strategy of isothermal forging and pressing, water quenching and two-stage aging is adopted in the process, and high-density dislocation and water quenching freezing dislocation configuration is introduced in forging and pressing so as to retain deformation stored energy. Two-stage aging promotes uniform dispersion of a precipitated phase, efficient superposition of deformation strengthening and precipitation strengthening is achieved, and the strength and fatigue resistance are remarkably improved. And finally, the strength, the electric conductivity and the fatigue limit of the alloy are synchronously improved while the high plasticity is kept, the bottleneck of mutual restriction of the strength and the corrosion resistance is effectively broken through, and the harsh requirements of aerospace on high-strength, high-electric-conductivity and high-fatigue materials are met.

The present invention enables the magnitude of stress generated at a fixed part of a double member to be equal to or less than a fatigue limit, and does not cause an increase in the size of a component and the difficulty of processing. In the present invention, a second member (6) includes a curved surface portion (6d) having, as a starting point (6d1), one end portion (6a1) in a direction along a center line (1A) of an outer peripheral surface (6a). The first member (1) includes: a pressed surface (1g) formed by pressing a peripheral edge portion (1c2) of an inner peripheral surface (1c1); and a plastic deformation part (1x1) that is plastically deformed further inward in the radial direction than the outer peripheral surface (6a) of the second member (6). When a circle (C1) is drawn, the radius of which is the length (R1) of a line segment (LS1) connecting the starting point (6d1) and the radially outer end point (1g1) of the surface to be pressed (1g), and the center of which is the radially outer end point (1g1) of the surface to be pressed (1g), the circle (C1) intersects the curved surface portion (6d). An angle ([theta] 1) formed between a tangent line (LS2) that is in contact with the curved surface portion (6d) at an intersection (CP) between the circle (C1) and the curved surface portion (6d) and a line (LS3) that is orthogonal to the center line (1A) is greater than 0 DEG.

A valve spring which has an excellent fatigue limit is provided. A chemical composition of the valve spring according to the present embodiment contains, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less. S: 0.020% or less: Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, Ca: 0.0001 to 0.0050%, and N: 0.0100% or less, with the balance being Fe and impurities. In the valve spring, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces / μm3, and a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.

The application relates to a kind of underwater wellhead-conduit reliability evaluation method and system, define the fatigue limit state of wellhead and conduit;According to the value range of the parameter that influences the fatigue life of underwater wellhead and conduit, random sampling is carried out in the value range of all the parameters, forming several groups of discrete data of random variables, and each group of discrete data of the random variables is composed of the single discrete point of all parameters after sampling;The stress range of underwater wellhead and conduit under the action of each group of discrete points is obtained, and then the function function of fatigue limit state represented by random variable is obtained;Solve the function function, obtain the fatigue life reliability index value of underwater wellhead and conduit, and then carry out reliability evaluation.Compared with the prior art, the reliability index value after solving can reflect the wellhead fatigue reliability under the multi-source randomness, and the accuracy of evaluation is better.

The present invention discloses a method for improving the corrosion resistance of an Al-Cu-Li alloy by composite ion implantation, comprising: performing thermoplastic deformation on the Al-Cu-Li alloy and pre-treating its surface, and then simultaneously implanting composite Zr, Ti, Zn, and Cr ions, wherein the Zr / Ti ion ratio is 1 to 3:1, and the Zn / Cr ion ratio is 1.5 to 2.5:1. The present invention uses composite Zr, Ti, Zn, and Cr ion implantation to ensure the stability of the alloy surface modification layer, improve the alloy hardness and wear resistance, and simultaneously improve the corrosion resistance and fatigue resistance of the permeation layer; the ion penetration depth is increased, avoiding the disadvantage of damage to the modified layer caused by a too-thin coating, further improving the hardness, wear resistance, and fatigue limit of the alloy; inhibiting matrix recrystallization, reducing the potential difference within the alloy grains and between the grain boundaries, and significantly improving the corrosion resistance of the alloy.

The embodiment of the invention relates to a structural member fatigue judgment method and device and simulation equipment, and the method comprises the steps: obtaining the information of a structural member, building a finite element model according to the information of the structural member, carrying out the random vibration response analysis of the finite element model, and obtaining the inherent frequency and RMS data; acquiring vibration duration and material parameters of the structural member, and calculating to obtain a fatigue limit value according to the vibration duration, the material parameters and the inherent frequency; obtaining a first judgment result according to the fatigue limit value and the stress result of the RMS data on the structural member, and when the RMS data is greater than the fatigue limit value, performing accumulated damage analysis on the structural member to obtain a second judgment result; and according to the first evaluation result and / or the second evaluation result, determining a joint risk level of the structural member. According to the method, the risk degree of the structural member can be determined, the risk area can be determined, and a direction is provided for optimization and improvement of the risk area.

The high-stress spring steel wire comprises the following chemical components in percentage by mass: 0.50 to 0.65 percent of C, 1.30 to 1.80 percent of Si, 0.50 to 0.80 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 0.80 to 1.00 percent of Cr, less than or equal to 0.10 percent of Cu, less than or equal to 0.06 percent of Mo, 0.20 to 0.50 percent of Ni, 0.02 to 0.05 percent of Nb, 0.05 to 0.15 percent of V, 0.03 to 0.06 percent of Ti, less than or equal to 0.008 percent of N, less than or equal to 0.02 percent of As, less than or equal to 0.015 percent of Sn, less than or equal to 0.0020 percent of O, less than or equal to 0.00010 percent of H and the balance of Fe. The method has the advantages that the strength and the fatigue performance of the device are effectively improved, the cost is saved, the influence of inclusions on the fatigue limit is greatly reduced, and the fatigue life of the material is remarkably prolonged.