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132 results about "Flow stress" patented technology

Flow stress is defined as the instantaneous value of stress required to continue plastically deforming the material - to keep the metal flowing. Hence, Flow stress can also be defined as the stress required to sustain plastic deformation at a particular strain.

Method for predicting nickel base alloy high temperature flow stress and dynamic recrystallization behavior

InactiveCN104928605AFlow stressHot working
The invention discloses a method for predicting nickel base alloy high temperature flow stress and a dynamic recrystallization behavior. The method comprises the following steps: 1 obtaining true stress-true strain data of nickel base alloy by means of high temperature compression tests; 2 establishing a unified constructive model for predicting the nickel base alloy high temperature flow stress and the dynamic recrystallization behavior; 3 utilizing the numerical value difference principle, writing an iterative accumulation algorithm program, inserting numerical value simulation software, and by combining the true stress-true strain data of the nickel base alloy, determining material parameters of the unified constructive model for predicting the nickel base alloy high temperature flow stress and the dynamic recrystallization behavior; 4 predicting the nickel base alloy high temperature flow stress and the dynamic recrystallization behavior under the constant temperature and constant strain rate condition as well as under the variable temperature and variable strain rate condition. By means of the method, the nickel base alloy high temperature flow stress and the dynamic recrystallization behavior under the constant temperature and constant strain rate condition as well as under the variable temperature and variable strain rate condition can be predicted rapidly and accurately, and important technical guidance significance for formulating the nickel base alloy hot working process reasonably is achieved.
Owner:CENT SOUTH UNIV

Method for vacuum scattering intermetallic compound for coupling TiAL

The invention relates to a TiAl-intermetallic-compound vacuum diffusing connection method, belonging to the TiAl-intermetallic-compound welding field, which overcomes the technical drawbacks of high temperature of diffusing connection and high pressure of diffusing connection in the prior TiAl-intermetallic-compound diffusing connection technology. The invention adopts hydrogenated titanium or titanium alloy chaff as the interface layer of diffusing connection. Ti3Al+TiAl dual phase (Alpha2+Gamma) organ can be formed under the temperature of diffusing connection titanium, which facilitates the formation of high-intensity connector lug of TiAl-intermetallic-compound diffusing connection. And hydrogen makes the flow stress of thermal deformation of titanium or titanium alloy decrease and the thermal plasticity increase, so that hydrogenated titanium or titanium alloy is prone to deform under high temperature. Meanwhile,, the self-diffusing capacity of hydrogen in titanium or titanium alloy and the diffusing capacity of solute are enhanced, more particularly, in Beta phase the capacities are more enhanced, so that hydrogen can accelerate the diffusing of the alloy elements, reduce the atomic combination energy and the diffusing activation energy, promote the diffusing coordinated deformation capacity, and the reliable diffusing connection of connector lug of TiAl-intermetallic-compound can be realized under comparatively low temperature.
Owner:HARBIN INST OF TECH

Analyzing and modelling method of milling force of flat spiral end milling cutter

The invention relates to an analyzing and modelling method of milling force of a flat spiral end milling cutter. According to the method, workpiece material characteristics, cutter geometry, cutting conditions and milling modes serve as model input parameters, consideration is given to the influence on the cutting force by a cutter cutting edge radius, a variable sliding friction coefficient and cutter bounce, shear flow stress is calculated through a Johnson-Cook constitutive model in a model, each cutting edge of the milling cutter is scattered into multiple microelements in the cutter axis direction, the cutting characteristic of each microelement is equivalent to an inclined cutting process, cutting force exerted on each cutting microelement is obtained through an analytical model of inclined cutting force, then cutting force of all the cutting microelement is superposed, and a milling force value of the milling cutter is obtained. According to the analyzing and modelling method of the milling force of the flat spiral end milling cutter, cutting mechanism, relevant stress, strain and a strain rate in the cutting process and the distribution situation of the temperature can be reflected truly, the milling force can be quickly predicted only by inputting the cutting conditions and workpiece characteristic parameters, and the method is high in accuracy and rapidity.
Owner:WUHAN INSTITUTE OF TECHNOLOGY

Refracturing well and layer selecting method based on four-dimensional crustal stress dynamic change

ActiveCN106991236ATo overcome the problem of inability to accurately reflect the change of ground stress in the process of oil and gas developmentOvercoming the problem of changing ground stressGeometric CADDesign optimisation/simulationFlow stressCoupling
The invention discloses a refracturing well and layer selecting method based on four-dimensional crustal stress dynamic change. The method includes the steps that S1, a three-dimensional geologic model is set up; S2, a three-dimensional oil deposit model is set up, and producton/injection dynamic parameters are used for predicting a three-dimensional pore pressure field and a temperature field of different periods; S3, a three-dimensional crustal stress model is set up; S4, an initial three-dimensional crustal stress field is formed; S5, a four-dimensional dynamic crustal stress model is set up; S6, interstifial flow-stress coupling solution is carried out, and dynamic crustal stress and pore elastic parameters are analyzed and calculated; S7, a refractured well and layer position are selected preliminarily; S8, interstifial flow-stress-fracture damage coupling model of refracturing is set up; S9, the final fracturing layer segment is determined. The refracturing well and layer selecting method has the advantages of being capable of accurately reflecting the change condition of dynamic crustal stress and pore elastic parameters in the oil and gas development process, optimizing the refractured well and layer position by combining the interstifial flow-stress-fracture damage coupling model, effectively improving oil and gas recovery degree and avoiding aquifer communicating.
Owner:SOUTHWEST PETROLEUM UNIV

Thermal hydro-mechanical drawing forming method for dot matrix self-impedance electrical heating plates

The invention relates to a thermal hydro-mechanical drawing forming method for dot matrix self-impedance electrical heating plates, and belongs to the technical field of the thermal hydraulic forming of the plates. The method comprises the following steps of: fully filling liquid into a cavity of a female die serving as a liquid pond; when the plates are driven by a male die to enter the female die, forming the plates by reverse pressure generated when the liquid is compressed; embedding pin type electrodes inside pressure plates according to the distribution of dot matrixes, and performing self-impedance electrical heating on flanges of the plates by using contact resistors between the electrodes and the plates; adjusting the distribution of temperature fields of the flanges by changing the distribution law of the dot matrixes of the electrodes and adjusting the heating current of each heating electrode; adjusting the flow stress of heating points by changing the temperature of each mass point on the flanges so as to control the flow of metal by the asynchronous flow of the metal mass points on the flanges; and coordinating the deformation process of the metal by the asynchronousdeformation of each mass point on the flanges due to the temperature to fulfill the aim of improving the limit drawing ratio of the plates. The method has the advantages that: the heating speed is high, the effect is good, the plates can be heated controllably and flexibly, and the forming limit of the plates is improved.
Owner:ANHUI UNIVERSITY OF TECHNOLOGY

Assembled type movable blast wall

An assembled type movable blast wall is formed by a plurality of blast wall units in an assembled mode. Each blast wall unit comprises a base, front pull rods, rear compression bars, a supporting frame, energy absorption layers and connecting bolts. Each supporting frame is fixed on the upper surface of the corresponding base, and one or more energy absorption layers are arranged inside each supporting frame in a filling mode. The energy absorption layers are formed by a plurality of prefabricated bodies which are made of EPS flow state concrete in an arrayed mode. A plurality of slide-resistant piles are distributed on the lower surface of each base. When multiple energy absorption layers are arranged, a middle layer is arranged between every two adjacent energy absorption layers. The assembled type movable blast wall can be deformed easily when undergoing impulse loads of the outside, the deformation is large, however, the flow stress level is quite low, in the compression deformation process, a large amount of power is consumed, the power is converted into energy dissipated in all sorts of modes like deformation, collapsing, fracturing and cell wall friction of holes in the structure, and thus the outside impact energy can be effectively absorbed. The assembled type movable blast wall further has the advantages of being rapid in assembling, low in cost and strong in stability.
Owner:AIR FORCE UNIV PLA

Method for producing an article by superplastic shaping and diffusion welding

The invention relates to metal forming, more specifically, to methods for producing titanium alloy articles by superplastic shaping and diffusion welding. The inventive method is particularly suitable for aviation engine building for producing a fan blade-type part. The inventive method for producing an article by superplastic shaping and diffusion welding from at least two titanium alloy blanks consists in designating connectable and not-connectable sections on the surface of at least one blank, in assembling the blanks into a packet, in heating said packet to a specified temperature (T), in exposing it to a specified pressure (p) in such a way that the blanks are connected to each other by diffusion welding and a semi-finished product is obtained, in heating and supplying a pressurised working medium into the semi-finished product internal cavity for superplastically shaping at least one blank in such a way that a desirably shaped article is produced. Said method differs from known methods in that the diffusion welding is carried out through titanium alloy plates whose flow stress is less than the blank flow stress, mainly, when the article is made from at least three blanks and a connection preventing material is applied to the non-connectable sections of at least one part of at least one blank surface.
Owner:INST SVERKHPLASTICHNOSTI METAL

Method for analyzing and preventing forging through flow and coarse-grain defects

InactiveCN102831265AAvoid reoccurrenceOptimizing the forging processSpecial data processing applicationsFlow stressCritical condition
The invention relates to a method for analyzing and preventing the forging through flow and the coarse grain defect, which comprises the following steps of: firstly, acquiring the original flow stress-strain data of a metal through an isothermal constant-strain-rate compression test, and constructing a constitutive model of the material; then, importing the data into finite element numerical simulation software, establishing a numerical analysis model, and calculating the metal flow, the stress strain and the temperature field distribution conditions inside a forging piece after the completion of calculation; additionally, physically simulating the forging process of the metal through an upsetting test to obtain the critical conditions such as temperature, strain and the like of the metal coarse grain; and analyzing the causes to the through flow and the coarse grain by combining the test results of numerical simulation and physical simulation, optimizing the forging process, and simulating to verify the optimized forging process in the finite element software. In the invention, the finite element numerical simulation technology and the physical simulation technology are innovatively combined, the optimization of the forging process is realized, the optimized forging process conditions can be verified, so that the material and energy sources can be saved, and the efficiency is increased.
Owner:NANCHANG HANGKONG UNIVERSITY

Recognition method of metal material cutting constitutive model parameters

The invention relates to a recognition method of metal material cutting structure model parameters. The method comprises the following steps of 1, adopting a JC constitutive model to describe a cutting constitutive model of a material; 2, conducting compression experiment and fitting on a metal material specimen to solve JC constitutive model parameters of the metal material under a low strain rate; 3, using the constitutive model parameters obtained by recognition through the compression experiment in the step 2 as an initial value to establish an optimization target function; 4, setting a standard value of an error between an experiment value of a flow stress and a predicted value, and obtaining a structure parameter optimal solution of the metal material specimen based on a genetic optimization algorithm; 5, verifying the correctness of the parameters obtained by recognizing the JC structure model of the metal material. According to the recognition method of the metal material cutting structure model parameters, the flow stress value obtained through the JC structure model is very close to an actual flow stress value of the metal material, and the efficiency in the process of recognizing the constitutive model parameters is very high; meanwhile, a special apparatus is not needed to conduct a large quantity of compression experiments, and therefore the cost is lowered.
Owner:WUHAN INSTITUTE OF TECHNOLOGY
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