254 results about "Corrosion fatigue" patented technology

The invention discloses a method for evaluating the fatigue life of an aged reinforced concrete bridge. The method comprises the following steps of obtaining initial corrosion time of reinforcement in concrete based on the second diffusion law of Fick, and considering the influence of concrete cracking due to corrosion expansion in a corrosion rate model; adopting a small crack growth and near threshold growth analysis and determining relevant parameters of fatigue crack propagation rate of materials by developing a fatigue crack propagation test of reinforced concrete materials; performing a corrosion fatigue test or finite element analysis on corroded reinforcement to obtain stress concentration factors at different corrosion levels, and integrating into a stress intensity factor model to obtain the fatigue crack propagation rate of the reinforcement under the influence of corrosion; comparing the magnitude of a corrosion pit growth rate and the fatigue crack propagation rate and gradually converting into a single growth analysis on fatigue cracks of the reinforcement; meanwhile, combining with vehicle load observing information to realize life evaluation of a bridge at different service stages. The prediction method disclosed by the invention is reasonable and high in popularization, and can provide technical support for evaluating the life of the concrete bridges.

The invention belongs to the field of material testing, specifically to a corrosion fatigue test apparatus with high temperature and high pressure circulating water. With the present invention, the problems of the complex structure and the cumbersome use and maintenance in the prior art are solved. The apparatus is provided with a high temperature and high pressure circulating water system, an autoclave and a fatigue machine. The high temperature and high pressure circulating water system is communicated with the autoclave. A test sample is placed in the autoclave, and is connected with a loading part of the fatigue machine. The high temperature and high pressure circulating water system comprises a water storage tank, a circulation pump, a high pressure pump, a buffer tank, a heat exchanger, a preheater, a condenser, a back pressure valve and an ion exchange resin. An inlet of the autoclave is connected with the heat exchanger through a pipeline. The pipeline is provided with the preheater. An outlet of the autoclave is connected with the heat exchanger through the pipeline. The high temperature and high pressure circulating water system is provided for providing high temperatureand high pressure water required by the test. The fatigue machine is provided for performing fatigue loading for the test sample in the autoclave. A control system controls the high temperature and high pressure circulating water system and the fatigue machine.

A rock drilling rod is manufactured by placing free ends of first and second hollow rod components in abutment, and establishing relative rotation between the free ends to friction weld those free ends together. The first component comprises a thread and a clearance portion disposed adjacent the thread. The first component has a hot hardness value of at least about 170 HV1 at 600 DEG C. Prior to friction welding the components together, the thread, clearance portion and central passage of the first component are heat treated against corrosion fatigue. Then, the thread is high frequency hardened to a depth at least as great as the heat treated layer. Following the welding, the weld is cooled while keeping a core hardness of the respective portions of the first and second components disposed immediately adjacent the weld no lower than 390 HV1.

The invention relates to a method for analyzing the residual life of a storage tank through ANSYS software. The method mainly comprises the following steps that (1) a computer supporting ANSYS is used, collected storage tank data are input to the computer in the form of a database or a text, a finite element model of the corroded storage tank is established through the ANSYS software, and corresponding boundary conditions and an external load are applied to the finite element model according to the actual stress condition of the storage tank; (2) regression processing is conducted on experimental data points through a fatigue crack propagation law Paris formula, and a corrosion fatigue rate equation under the corresponding conditions is obtained; (3) the critical invalid wall thickness when the storage tank loses efficacy is determined according to a predicted value of the corrosion rate; (4) according to the critical invalid wall thickness when the storage tank loses efficacy due to corrosion, a storage tank residual life prediction model is established, and the approximate analysis method is used for calculating the residual life of the storage tank under the condition of uniform corrosion.

The invention belongs to technical field of metal material corrosion and particularly relates to a corrosion fatigue life prediction method based on damage evolution. The method includes following steps: carrying out a stress corrosion test to a to-be-tested material for determining a stress threshold value of the stress corrosion and a damage index; carrying out a fatigue test to the to-be-tested material for determining a fatigue damage parameter; determining a corrosion fatigue damage nonlinear evolution index of the to-be-tested material; and predicting a corrosion fatigue life of the to-be-tested material. A corrosion solution circulating device in the invention can achieve cyclic refreshing of a corrosion liquid in a metal material corrosion fatigue and stress corrosion test. The corrosion fatigue life is predicted through a method of combining theory with experimental investigation so that defects in an analytical method and a test method are overcome. The prediction method is reasonable and is accurate in result. The predicted result is free of any influence due to combination of environment and the material. The prediction method is simple in operation, is easy to carry out, is strong in popularizing performance and is convenient in engineering application.

The invention discloses a rotary bending corrosion fatigue test device. The device includes a rotary bending fatigue test device and a corrosion liquor supplying system; wherein, the rotary bending fatigue test device is used for mounting a test piece and applies bending load on the test piece during the process of driving the test piece to rotate and realizes the test on the fatigue data of the test piece. The corrosion liquor supplying system includes a liquor storage tank, a transfusion pump, a flow adjusting valve and a connecting pipeline. The corrosion liquor supplying system feeds the corrosion liquor to the test piece during testing in real time from an output opening. The invention realizes the testing on the middle, high cycle and ultra-high cycle corrosion fatigue performance of the material by adding the corrosion liquor supplying system based on the existing rotary bending fatigue test device machine. As the design of the test device is approximate to an engineering design, the measured result by using the device has a greater reference value to the engineering design. The corrosion fatigue test device of the invention has the advantages of simple structure and convenient operation, and can get standardized test results.

The invention discloses a method for predicting the service life of a reinforced concrete bridge under the conditions of seasonal corrosion and fatigue coupling. The method comprises the steps: dividing the service life of the reinforced concrete bridge into three stages: corrosion initiation-pure fatigue crack development stage, a rust pit and fatigue crack competing development stage and a structure failure stage; establishing an initial reinforcing steel bar corrosion model and a rust pit growth model based on the Fick second diffusion law and the consideration of the influence of concreterust expansion cracking damage; testing and simulating a reinforcing steel bar crack propagation rule under the influence of a four-season environment, and determining fatigue crack growth characterization parameters; constructing a stress intensity factor model considering the influence of stress concentration, and proposing a steel bar corrosion fatigue crack growth analysis method correspondingto a four-season environment; enabling the structural failure criterion to be clear, combining with the vehicle load observation information, performing the systematic consideration of the competitive coupling relation between rust pit growth and fatigue crack growth, judging a failure mode in real time, and achieving the prediction of the service life of the bridge. The method is novel and reasonable, and can provide technical support for safety assessment of the concrete bridge.

The invention discloses a high-temperature and high-pressure water vapor environment structural material testing device. The testing device is provided with a pipe, wherein high-temperature water flows inside and outside the pipe. The testing device comprises an autoclave, a test tube loading system, a loop system inside a test tube, a loop system outside the test tube, a controlling and measuring system and a data acquisition and processing system. The testing device which can be used for simulating the temperature, pressure, flow velocity, water chemical conditions, load and the like of a high-temperature and high-pressure water vapor environment structural material is applicable to tests in the aspects of corrosion, stress corrosion, corrosion fatigue, flow accelerated corrosion and the like of tubular specimens through complex flow and complex load coupling effect. Especially, the working conditions of different flow, different inner-side and outer-side temperatures, different pressures and different water chemistry in a heat exchange tube of a steam generator in a nuclear reaction pressurized-water reactor can be simulated to carry out related testing and research on the heat exchange tube.

The invention relates to a Cr 23 Ni 6 ferrite-austenitic stainless steel which is manufactured from stainless steel materials containing components by weight percentage as follows: 22 percent to 24 percent of Cr, 5 percent to 7 percent of Ni, 3 percent to 4 percent of Mo, 0.15 percent to 0.25 percent of N, less than or equal to 0.03 percent of C and 1 percent to 2 percent of Mn, and the rest is Fe. The manufacturing technology of the Cr 23 Ni 6 ferrite-austenitic stainless steel of the invention is characterized in that: in hot piercing process, the hot piercing temperature is controlled to be 1150 DEG C to 1200 DEG C; the prior compression coefficient of a piercing plug is controlled to be 5 percent; the reduction of roller waist is controlled to be 12 percent and the ovality is controlled to be 1.08 to 1.11; in cold drawing/cold rolling process, cold deformation quantity is controlled to be below 50 percent; in heat treatment process, the solid solution temperature of products is controlled to be 1080 DEG C to 1100 DEG C and the solid solution temperature of finished products is controlled to be 1050 DEG C to 1100 DEG C. The Cr 23 Ni 6 ferrite-austenitic stainless steel has good chloride stress corrosion resistance, good pit corrosion resistance, high tensile strength and yield strength and good corrosion fatigue resistance and erosion corrosion resistance, and is widely used in the fields such as petroleum industry, chemical industry, natural gas industry and marine shipping and the like.

The invention relates to a test system for the extension of a multi-axis and salt-spray corrosion fatigue crack. The test system comprises a fatigue tester for providing I-type, II-type, III-type and compound fatigue loads required by a test for a test sample through a pull-cut-twist multi-axis loading fixture, and further comprises a salt-spray corrosion environmental box, wherein the salt-spray corrosion environmental box comprises a salt-spray corrosion box body and a salt-spray pre-occurrence box body which are mutually communicated through a pipeline; the salt-spray pre-occurrence box body conveys air and salt water required by salt-spray forming to the salt-spray corrosion box body; the salt-spray corrosion box body provides a required salt-spray corrosion environment for the fatigue crack extension test; both the pull-cut-twist multi-axis loading fixture and the fatigue crack extension test sample are positioned in the salt-spray corrosion box body. Through the adoption of the test system, the fatigue crack extension rate and other fracture mechanics parameters under the combined action of multi-axis loads and the salt-spray corrosion environment can be measured relatively well, and thus the material selection design and the service life evaluation for marine engineering equipment serving in the salt-spray corrosion environment and under a complex stress state can be supported.

The invention relates to the fields of metal material accelerated corrosion and corrosion fatigue, in particular to equipment for implementing synchronous dry-wet alternate accelerated corrosion in aloading process and application thereof. In the equipment, a temperature control device and a humidity control device sense temperature and humidity in a corrosion fatigue tank, and transmit signals to a control system, and the control system sends an instruction for adjusting the temperature and humidity in the corrosion fatigue tank to implement temperature control and humidity control. Simultaneously, a loaded sample in the corrosion fatigue tank is regularly sprayed through the instruction of the control system so as to implement dry-wet alternate corrosion. The equipment can assist fatigue testers and slow strain equipment to implement the synchronous dry-wet alternate corrosion of the sample in the fatigue, tensile or slow strain process, also can be used for simulating temperature control and humidity control corrosion fatigue, tensile or slow strain tests under different weather conditions, and temperature control and humidity control dry-wet alternate corrosion tests, and implements the synchronous dry-wet alternate accelerated corrosion in the corrosion fatigue process and in the slow strain process.

The invention relates to an electrolytic cell device of electrochemistry electrochemistry for performing corrosion fatigue crack propagation experiment on metal materials, belonging to the technical field of material corrosion research, mainly comprising a front trough solid, a rear trough solid, a three point bending specimen, a bolt, a water outlet, a water inlet, an auxiliary electrode, a salt bridge, a reference electrode and a conical flask; the front trough solid and the rear trough solid are symmetrical halfbody structures, which fix the electrolytic cell in a box shaped structure on two sides of the three point bending specimen through a thru bolt. A groove placing auxiliary electrode is arranged at the center of the front plate inner side of the front trough solid. One end of the salt bridge communicates with the auxiliary electrode and the work electrode through etching solution, and the other end is connected with the reference electrode through the conical flask full of saturated potassium chloride solution. A left posterior lateral plate and a right posterior lateral plate have the same height and the same width with a left front lateral plate and a right front lateral plate, which is a symmetrical shape and structure, having simple and practical structure, multiple measurable functions, long service life, high measuring precision and good accuracy.

Embodiments of an ultra-fine-grained, medium carbon steel are disclosed herein. In some embodiments, the ultra-fine grained steel can have high corrosion fatigue resistance, as well as high toughness and yield strength. The ultra-fine grained steels can be advantageous for use as sucker rods in oil wells having corrosive environments.

The invention relates to a heat treatment method capable of improving the anti-fatigue performance of Al-Cu-Mg alloy. The method comprises the following steps: performing intermediate annealing on a cold-rolled plate at the temperature of between 300 and 440 DEG C for 20 to 120 minutes; performing solution hardening treatment at the temperature of between 475 and 505 DEG C for 10 to 120 minutes; and naturally ageing at room temperature for at least 100 hours. The Al-Cu-Mg alloy comprises the following components: Cu, Mg, Mn, Ti and Al. The process method is simple and reasonable. By the intermediate annealing heat treatment process, the Gauss texture score of the alloy is increased, and orientation of most of crystal faces {111} of crystal grains of the cold-rolled Al-Cu-Mg alloy is positioned or close to the direction of the maximum external shearing stress, so that reciprocating sliding dislocated under the action of alternating stress is promoted, the closed effect of fatigue crack is improved, the spreading rate of the fatigue crack is reduced, and the alloy has excellent stress corrosion resistance and anti-stripping corrosion fatigue performance and is suitable for industrialized application.

The invention discloses a corrosion fatigue test apparatus in wet hydrogen sulfide environment, and a test method thereof. The apparatus comprises a fatigue test machine, and also comprises a closed corrosion environment box arranged in the working section of the fatigue test machine and having a corrugated expansion joint, a circulating water system arranged outside the closed corrosion environment box and used for heating a corrosion medium in the closed corrosion environment box, and an online liquid sampling device connected with the closed corrosion environment box and used for measuring and regulating the concentration of the corrosion medium in real time; and a sample in the closed corrosion environment box is clamped by a clamp adapting to the sample, and the clamp traverses through the upper cover board and the lower baseboard of the closed corrosion environment box, and is connected with the fatigue test machine. The apparatus has a simple structure and a good sealing performance, and can be used for carrying out corrosion fatigue performance test of fatigue samples with different shapes and dimensions in the wet hydrogen sulfide environment; and the test method of the apparatus has a temperature control function, can be used for online measurement of the concentration of hydrogen sulfide in a corrosion solution, and improves the accuracy of a test result.

The invention provides a method for monitoring and recognizing pulling rope corrosion and evaluating a fatigue life on the basis of computer vision. The method comprises the following steps: shootingan image of a corroded high-strength steel wire by a perspective inspection window at an anchoring end of a pulling rope, extracting image characteristics from the image, then building a corrosion-degree evaluation model, then building a fatigue-life characteristic energy number evaluation model, matching with a performance degrading state of the corrosion and the fatigue of the steel wire under an artificially accelerated corrosion test, and finally finishing the corrosion-state recognition and the fatigue-life evaluation of the in-service pulling rope. The method provided by the invention has the beneficial effects that the recognition accuracy is high, the speed is fast and the cost is low; the requirement for real-time data processing of online monitoring and early warning of corrosionand fatigue of the pulling rope also can be met, i.e., the image acquired by a consumer-grade ordinary camera is directly recognized without data-set updating; the automation, intelligentization, accuracy and robustness of corrosion monitoring and recognition and fatigue-life evaluation of the pulling rope are improved, and a solution is provided for automatic monitoring and recognition of the corrosion and the fatigue of the pulling rope of a bridge structure.

The invention discloses a device and a method for testing metal corrosion fatigue crack extension. The device comprises a pedestal and a corrosive medium accommodation container, wherein a fatigue machine clamping piece is designed on the lower surface of the pedestal and used for clamping the lower chuck of the fatigue machine; a testing specimen locking piece is designed on the upper surface of the pedestal and used for fixing the lower end of a fatigue testing specimen; the upper end of the fatigue testing specimen is clamped by a fatigue machine upper clamp; the alternating load of the fatigue machine can be transferred to the testing specimen through the fatigue machine clamping piece; the corrosive medium accommodation container adopts a cylindrical structure; the bottom end of the cylindrical structure is fixedly mounted on the upper surface of a circular table in the pedestal; the testing specimen locking piece in the pedestal is positioned in the corrosive medium accommodation container. The device is used for testing according to the test fatigue testing parameters until the working section of the fatigue testing specimen is broken; in the process, a microscope is utilized to record and shoot the producing-extending-fracturing process of the crack. The device disclosed by the invention has the advantage of realizing the corrosive fatigue performance test of the metal material in the corrosive medium under the standing state.

The invention relates to a skin material for aviation, in particular to a machining method for preparing corrosion-fatigue-damage-resistant aluminum alloy plates, and belongs to the technical field ofnonferrous metals. The machining method comprises the steps that an aluminum alloy hot rolling material is subjected to solid solution treatment for the first time, then the second time of solid solution treatment is carried out after multi-pass cold rolling with the pass deformation amount being less than or equal to 1.0mm is carried out to achieve the design thickness of the aluminum alloy plate; and in the multi-pass cold rolling process, deep cooling treatment is carried out immediately after each pass of cold rolling, and the temperature of the deep cooling treatment is less than or equal to -100 DEG C. The machining method for preparing the corrosion-fatigue-damage-resistant aluminum alloy plates is reasonable in texture design, the preparation process is simple and controllable, obtained products have good performance, and the machining method for preparing the corrosion-fatigue-damage-resistant aluminum alloy plates is convenient for large-scale industrial application.