CN102445491A - Method for evaluating stress concentration degree of remanufactured blank by using self-emission magnetic signal - Google Patents
Method for evaluating stress concentration degree of remanufactured blank by using self-emission magnetic signal Download PDFInfo
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- CN102445491A CN102445491A CN2011103071842A CN201110307184A CN102445491A CN 102445491 A CN102445491 A CN 102445491A CN 2011103071842 A CN2011103071842 A CN 2011103071842A CN 201110307184 A CN201110307184 A CN 201110307184A CN 102445491 A CN102445491 A CN 102445491A
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Abstract
The invention discloses a method for quantitatively evaluating the stress concentration degree of a waste and used ferromagnetic part by using a self-emission magnetic signal, belonging to the technical field of nondestructive detection. The method comprises the following steps of: manufacturing a test piece by using a material which is the same as that of the tested waste and used ferromagnetic part, designing different tests for corresponding bending, torque, impact, fatigue and the like, and scanning a stress concentration region on the surface of the test piece according to a fixed lift-off value by using a magnetic sensor in the testing process to obtain a self-emission magnetic signal of the stress concentration region; computing the obtained signal, extracting multiple characteristic parameters, and establishing a mapping relation model between the characteristic value of the self-emission magnetic signal of the stress concentration region and the stress concentration degree by using a nerve network; and detecting a self-emission magnetic signal of a potential dangerous region on the surface of a tested member by using the same lift-off value, and quantitatively evaluating the stress concentration degree of a tested ferromagnetic test piece according to the mapping relation model between the characteristic value of the self-emission magnetic signal and the stress concentration degree. The evaluation reliability of stress concentration with a metal magnetic memory technology is enhanced, operation is simple and convenient, and high repeatability is achieved.
Description
Technical field
The present invention relates to a kind of method of utilizing the evaluation of self-emission magnetic signal to make the blank stress concentration degree again, belong to technical field of nondestructive testing.
Background technology
Making blank again is the production object of making again, and they are the waste and old components of machine of taking turns the military service cycle through.These waste and old parts possibly produce damage in the process under arms, even generate defective.Must evaluation before making make the degree of injury of blank more again, judge that it has or not manufacturing value again, the waste and old parts that only have again manufacturing value can be made again.
The blank of manufacturing again to generating gross imperfection uses conventional lossless detection method, all can find like technology such as ray, ultrasonic, eddy current, magnetic force, permeation flaw detections, but these methods can't be diagnosed the early stage implicit damage of making blank again.Making manufacturing enterprise at present mainly adopts inspection techniques such as magnetic, ultrasonic, infiltration, hydraulic pressure to detect waste and old part dangerous defectives such as flawless are arranged.As do not find defective, and thinking that then these waste and old has manufacturing value again, can make again, though this just makes that not having gross imperfection has the waste and old part entering of earlier damage to make production procedure again, buries hidden danger of quality.
Because it is very difficult that the complicacy and the disguise of earlier damage, Nondestructive Evaluation are made the earlier damage degree of blank again.The metal magnetic memory technology is the advanced nondestructiving detecting means that forms the end of the nineties; It utilizes ferromagnetic material to receive the load excitation under arms in the process and the self-emission magnetic signal of spontaneous generation finds that potential stress concentrates the position, receives publicity owing to damage field in early days has potentiality.The Russia scholar proposes to estimate ferromagnetic material stress intensity size with the Grad of magnetic signal normal component as the author of metal magnetic memory technology, sets up experimental formula (1) as follows:
In the formula (1): Δ H
pThe variation of expression ferromagnetic materials surface self-emission magnetic signal normal component; Δ l
kRepresent the length that corresponding probe detects.
At present,, all be the basis, estimate the hazard level of ferromagnetic parts region of stress concentration with this formula in engineering field and sphere of learning.Yet; Because to different ferromagnetic components; The correlativity of many influence factors such as its chemical constitution, physical dimension, Service Environment, military service load and self-emission magnetic signal Changing Pattern is not clarification as yet; Lack the verification standard of stress concentration degree, can only carry out qualitative evaluation to similar part stress concentration degree according to formula (1), the ferromagnetism that is difficult to quantitative comparison different structure, function and service condition is made the stress concentration degree of blank again.
In the prior art; Application number 200710119911.6 is only arranged; The magnetic memory detecting method that the Chinese invention patent of publication number CN101122578A---ferromagnetic metal component fatigue crack and stress are concentrated; Propose a kind of magnetic and show that SCF characterizes the method for ferromagnetic material stress intensity, with the horizontal component H of self-emission magnetic signal
p(x) ratio of signal magnetic field intensity maximal value and minimum value is as standard of comparison, and this method remains a kind of stress concentration degree qualitative evaluating method, the comparison of inapplicable different parts.
Summary of the invention
The objective of the invention is to invent a kind of novel detection method that utilizes ferromagnetic part stress concentration degree under the different service conditions of self-emission magnetic signal quantitative evaluation.
The test specimen that is a kind of through prefabricated series of standards SCF provided by the present invention; Under different service conditions, make an experiment; Obtain the mapping relations of self-emission magnetic signal characteristic parameter and SCF; Utilize these mapping relations to estimate the stress concentration degree at waste and old ferromagnetic part potential danger position, realize utilizing the quantitative evaluation of self-emission magnetic signal to make the target of blank stress concentration degree again.
The present invention realizes through following technical scheme:
A kind of method of utilizing the waste and old ferromagnetic part stress concentration degree of self-emission magnetic signal quantitative evaluation is characterized in that this method comprises following each step:
1) standard specimen of the material series SCF of employing and the identical material of tested waste and old ferromagnetic part, the final processing before surface quality when dispatching from the factory according to tested waste and old ferromagnetic part new product and heat treatment regime require to use;
2) the vertical standard specimen of Magnetic Sensor surface, according to fixing lift-off value, the stress on scanning standard test specimen surface is concentrated the position, obtains that test specimen detects surperficial self-emission magnetic signal under the original state;
3) according to the requirement of tested ferromagnetic part service condition; Design is corresponding crooked, reverse, impact, tired one or more different tests types; Carry out the test of SCF standard specimen, utilize the vertical test specimen of Magnetic Sensor surface in the process of the test, according to step 2) identical fixedly lift-off value; The region of stress concentration on scanning test specimen surface, the self-emission magnetic signal of acquisition region of stress concentration; Normal root is definite according to the designed life of tested part really to detect number of times; Repeat above-mentioned steps, destroy until standard specimen;
4) signal that in above-mentioned steps, records of Magnetic Sensor extracts self-emission magnetic signal horizontal component H through computing
p(x) or normal component H
p(y) or tangential component H
pOne of (z) or the characteristic parameter of two kinds or three kinds, adopt neural network to set up the eigenwert of standard specimen region of stress concentration self-emission magnetic signal and the mapping relations model of stress concentration degree;
5) adopt step 2) used Magnetic Sensor; According to step 2) identical lift-off value; Detect the self-emission magnetic signal in tested ferromagnetic piece surface potential danger zone; According to the self-emission magnetic signal characteristic quantity of confirming in the step 4) and the mapping relations of stress concentration degree, the stress concentration degree of the tested ferromagnetic test specimen of quantitative evaluation;
The metering system of above-mentioned self-emission magnetic signal is that standard specimen and tested ferromagnetic part are measured under unloaded state.
The Magnetic Sensor that uses is measured one of two-dimentional or three-dimensional or two kinds of perhaps three kinds the magnetic signals of the one dimension of the own stray field of ferromagnetic material, is normal component H
p(y) signal, horizontal component H
p(x) signal or tangential component H
p(z) one of signal or two kinds or three kinds of signals, measuring accuracy is equal to or higher than 1A/m.
The method that the present invention confirms utilizes ferromagnetic material self-emission magnetic signal to realize the quantitative evaluation of stress concentration degree, need not also need not do any pre-service to waste and old piece surface to tested waste and old ferromagnetic part extrinsic motivated magnetic field and demagnetizer.
Description of drawings
The stress that Fig. 1 adopts for the present invention concentrates standard specimen and detection line to arrange
Fig. 2 concentrates surperficial two-dimentional magnetic signal distribution characteristics in the standard specimen torture test process for the stress that the present invention adopts
Embodiment
The present invention realizes through following measure:
Tested construction material is the 42CrMo steel, and self-emission magnetic signal detecting instrument is that EMS-2003 type metal magnetic memory testing instrument (detects normal component H
pSignal) and RM-1 type magnetic memory detector (detection level component H (y)
p(x) signal).
1) selects the ferromagnetic material 42CrMo steel identical for use, make stress concentration factor K according to national standard with tested member material
tThe SCF test specimen of five kinds of prefabricated otch of=1～5, surfaceness R
aHigher limit be 0.4 μ m, be heated to 860 ℃, be incubated 30 minutes, oil quenching, then 540 ℃ of high temperings are 2 hours, cool to the air cooling of coming out of the stove below 200 ℃ with the furnace, obtain pure initial magnetic state.
Prefabricated cutting part in both sides, test specimen surface, every detection line interval 1mm arranges 10 parallel detection lines altogether, covers prefabricated otch.Detection line length 100mm is shown in accompanying drawing 1.
2) Magnetic Sensor that adopts is based on Hall unit, but the 2D signal of collection surface stray magnetic field, i.e. the normal component H of self-emission magnetic signal
p(y) signal and horizontal component H
p(x) signal, accuracy of detection are 1A/m.Transducer vertical test specimen surface, lift-off value 1mm scans each detection line respectively with straightaway mode (direction of scanning is shown in accompanying drawing 1 arrow), gathers the 2D signal of test specimen original state lower surface stray magnetic field, obtains H
p(x) and H
p(y) signal distributions.
3) counter stress concentrates standard specimen to apply permanent width of cloth drawingand pressing fatigue load, according to the military service loading spectrum of true part, sets maximum stress σ
Max=160MPa, stress ratio R=-1, frequency f=30Hz.Be loaded under the cycle index of the standard specimen initial stage of fatigue lifetime, mid-term and later stage; Test specimen is taken off in unloading respectively; Test specimen is positioned on the non magnetic three-dimensional platform along the terrestrial magnetic field North and South direction, moves according to fixed form, obtain the 2D signal that test specimen stress is concentrated the surface, position by the automatically controlled scanning support control of three-dimensional Magnetic Sensor detection line; Signal is sent into Computer Processing, obtains this cycle index lower surface stray magnetic field normal component and distributes.Repeat above-mentioned steps, obtain under the different SCF, the fatigue life cycle and the test specimen surface stray magnetic field 2D signal regularity of distribution (shown in accompanying drawing 2) are until test specimen germinating fatigue crack.
4) adopt Matlab software to extract H
p(y) two characteristic parameters of the peak-to-peak value of signal and peak-to-peak slope value, H
p(x) three characteristic quantities such as the peak width of signal, peak height and kurtosis factor; With these five signal characteristic quantities is that input vector is set up three layers of BP network model; The output layer neuron number is 1; Be test specimen stress concentration degree value, set up the BP neural network model of self-emission magnetic signal characteristic quantity and stress concentration degree mapping relations.
5) adopt step 2) used Magnetic Sensor; According to step 2) identical lift-off value; Detect the self-emission magnetic signal in tested ferromagnetic piece surface potential danger zone; According to the two-dimentional magnetic signal characteristic quantity of confirming in the step 4) and the neural network model of stress concentration degree, the stress concentration degree of the tested ferromagnetic test specimen of quantitative evaluation.
Claims (2)
1. method of utilizing the waste and old ferromagnetic part stress concentration degree of self-emission magnetic signal quantitative evaluation is characterized in that this method comprises following each step:
1) standard specimen of the material series SCF of employing and the identical material of tested waste and old ferromagnetic part, the final processing before surface quality when dispatching from the factory according to tested waste and old ferromagnetic part new product and heat treatment regime require to use;
2) the vertical standard specimen of Magnetic Sensor surface, according to fixing lift-off value, the stress on scanning standard test specimen surface is concentrated the position, obtains that test specimen detects surperficial self-emission magnetic signal under the original state;
3) according to the requirement of tested ferromagnetic part service condition; Design is corresponding crooked, reverse, impact, tired one or more different tests types; Carry out the test of SCF standard specimen, utilize the vertical test specimen of Magnetic Sensor surface in the process of the test, according to step 2) identical fixedly lift-off value; The region of stress concentration on scanning test specimen surface, the self-emission magnetic signal of acquisition region of stress concentration; Normal root is definite according to the designed life of tested part really to detect number of times; Repeat above-mentioned steps, destroy until standard specimen;
4) signal that in above-mentioned steps, records of Magnetic Sensor extracts self-emission magnetic signal horizontal component H through computing
p(x) or normal component H
p(y) or tangential component H
pOne of (z) or the characteristic parameter of two kinds or three kinds, adopt neural network to set up the eigenwert of standard specimen region of stress concentration self-emission magnetic signal and the mapping relations model of stress concentration degree;
5) adopt step 2) used Magnetic Sensor; According to step 2) identical lift-off value; Detect the self-emission magnetic signal in tested ferromagnetic piece surface potential danger zone; According to the self-emission magnetic signal characteristic quantity of confirming in the step 4) and the mapping relations of stress concentration degree, the stress concentration degree of the tested ferromagnetic test specimen of quantitative evaluation;
The metering system of above-mentioned self-emission magnetic signal is that standard specimen and tested ferromagnetic part are measured under unloaded state.
2. a kind of method of utilizing the waste and old ferromagnetic part stress concentration degree of self-emission magnetic signal quantitative evaluation according to claim 1; It is characterized in that: the Magnetic Sensor of use is measured one of two-dimentional or three-dimensional or two kinds of perhaps three kinds the magnetic signals of the one dimension of the own stray field of ferromagnetic material, is normal component H
p(y) signal, horizontal component H
p(x) signal or tangential component H
p(z) one of signal or two kinds or three kinds of signals, measuring accuracy is equal to or higher than 1A/m.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102706953A (en) * | 2012-05-30 | 2012-10-03 | 西南石油大学 | Rapid detection method for stress concentration of heat-treated workpiece |
| CN111289608A (en) * | 2020-03-23 | 2020-06-16 | 江苏科技大学 | Method for evaluating welding residual stress |
| CN114942090A (en) * | 2022-04-11 | 2022-08-26 | 江苏科技大学 | Correction method for evaluating stress of ferromagnetic cladding layer based on self-emission magnetic signal |
Citations (4)
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| JP2006313082A (en) * | 2005-05-06 | 2006-11-16 | Chugoku Regional Development Bureau Ministry Of Land Infrastructure & Transport | Flaw detector and flaw detecting method |
| CN101126799A (en) * | 2007-09-28 | 2008-02-20 | 中国人民解放军装甲兵工程学院 | Method for monitoring fatigue damage using ferromagnetic materials surface stray magnetic field signal |
| US20090301206A1 (en) * | 2005-12-17 | 2009-12-10 | Andre Yashan | Method and System for Non-destructively Testing a Metallic Workpiece |
| CN101122578B (en) * | 2007-08-03 | 2010-06-09 | 中国人民解放军装甲兵工程学院 | Ferromagnetic metal component fatigue crack and stress integrated magnetic memory testing method |
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2011
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006313082A (en) * | 2005-05-06 | 2006-11-16 | Chugoku Regional Development Bureau Ministry Of Land Infrastructure & Transport | Flaw detector and flaw detecting method |
| US20090301206A1 (en) * | 2005-12-17 | 2009-12-10 | Andre Yashan | Method and System for Non-destructively Testing a Metallic Workpiece |
| CN101122578B (en) * | 2007-08-03 | 2010-06-09 | 中国人民解放军装甲兵工程学院 | Ferromagnetic metal component fatigue crack and stress integrated magnetic memory testing method |
| CN101126799A (en) * | 2007-09-28 | 2008-02-20 | 中国人民解放军装甲兵工程学院 | Method for monitoring fatigue damage using ferromagnetic materials surface stray magnetic field signal |
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| LENG JIAN CHENG ET AL.: "Application of empirical mode decomposition in early diagnosis of magnetic memory signal", 《J. CENT. SOUTH UNIV. TECHNOL》 * |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102706953A (en) * | 2012-05-30 | 2012-10-03 | 西南石油大学 | Rapid detection method for stress concentration of heat-treated workpiece |
| CN111289608A (en) * | 2020-03-23 | 2020-06-16 | 江苏科技大学 | Method for evaluating welding residual stress |
| CN111289608B (en) * | 2020-03-23 | 2023-03-21 | 江苏科技大学 | Method for evaluating welding residual stress |
| CN114942090A (en) * | 2022-04-11 | 2022-08-26 | 江苏科技大学 | Correction method for evaluating stress of ferromagnetic cladding layer based on self-emission magnetic signal |
| CN114942090B (en) * | 2022-04-11 | 2024-05-03 | 江苏科技大学 | Correction method for evaluating ferromagnetic cladding layer stress based on self-emission magnetic signal |
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