SU974246A1

SU974246A1 - Ferromagnetic material checking method

Info

Publication number: SU974246A1
Application number: SU813292317A
Authority: SU
Inventors: Рустам Сабитович Ильясов; Владимир Александрович Комаров; Николай Иосифович Шакшин; Геннадий Иванович Деордиев
Original assignee: Институт Физики Металлов Уральского Научного Центра Ан Ссср
Priority date: 1981-05-21
Filing date: 1981-05-21
Publication date: 1982-11-15

Description

Изобретение относится к акустическим методам неразрушающего контроля и может быть использовано в металлургической и металлообрабатывающей промышлен— ' ности для контроля структурного состояния и динамических магнитострикционных ⁵характеристик полуфабрикатов и изделий из электротехнических и малоуглеродистых сталей.The invention relates to acoustic non-destructive testing methods and can be used in the metallurgical and metal-working industry for monitoring the structural state and dynamic magnetostrictive ⁵ characteristics of semi-finished products and products from electrical and low-carbon steels.

Известен способ контроля ферромагнит» ных материалов, при котором в изделии при наличии постоянного магнитного поля возбуждают ультразвуковые колебания, регистрируют сигнал, наведенный на специальную измерительную катушку, _<5 помещенную в пучности давления на изделии, и по разности фаз между возбуждающим и наведенным сигналам судят о механических свойствах изделия £ l^j .A known method of controlling ferromagnetic materials, in which ultrasonic vibrations are excited in a product with a constant magnetic field, records a signal induced on a special measuring coil _<5 placed in the antinode of pressure on the product, and judging by the phase difference between the exciting and induced signals mechanical properties of the product £ l ^ j.

Наиболее близким по технической сущности к изобретению является способ . контроля ферромагнитных материалов, заключающийся в том, что материал под- магничивают постоянным полем, возбуждают в нем упругие колебания, изменяют частоту колебаний, регистрируют акустический сигнал на частоте резонанса этих колебаний, определяют зависимость амплитуды этого сигнала от величины подмагничивающего поля и по величине подмагничивающего поля, соответствующей максимуму амплитуды акустического сигнала, судят о свойствах материала £2} .The closest in technical essence to the invention is a method. control of ferromagnetic materials, which consists in the fact that the material is magnetized by a constant field, excite elastic vibrations in it, change the oscillation frequency, record the acoustic signal at the resonance frequency of these oscillations, determine the dependence of the amplitude of this signal on the magnitude of the magnetizing field and the magnitude of the magnetizing field, corresponding to the maximum amplitude of the acoustic signal, judge about the properties of the material £ 2}.

Общим недостатком известных способов является низкая точность измерений характеристик материалов вследствие влияния величины подмагничивающего поля Но на механические и магнитные характеристики материалов, в частности кажущуюся магнитную проницаемость# кот ^{и зат}У^ха“ емость Q , (добротность Q Г упругих колебаний. В случае же магнитомягких материалов влияние Но на /ϊ_καχ и Q не позволяет однозначно установить величину подмагничивающего поля, соответствующую максимуму амплитуды акустического > сигнала.A common drawback of known methods is the low accuracy of measuring the characteristics of materials due to the effect of the magnitude of the magnetizing field, but the mechanical and magnetic properties of materials, in particular the apparent permeability # cat ^{and tightening} Y ^ha "emost Q, (Q factor Q T of elastic vibrations. In the case of magnetic materials the effect of Ho on / _{ϊ καχ} and Q does not allow us to unambiguously establish the magnitude of the magnetizing field corresponding to the maximum amplitude of the acoustic> signal.

II

Цель изобретения - повышение точности контроля и обеспечение возможности контроля магнитомягких материалов.The purpose of the invention is to increase the accuracy of control and providing the ability to control soft magnetic materials.

Поставленная цель достигается тем, что согласно способу контроля ферромагнитных материалов, заключающемуся в том, что материал подмагничивают постоянным полем, возбуждают в нем упругие колебания, изменяют частоту колебаний, регистрируют акустический сигнал на частоте резонанса этих колебаний, определяют зависимость амплитуды этого сигнала от величины подмагничивающего поля и по величине подмагничивающего поля, соответствующей максимуму амплитуды акустического сигнала, судят о свойствах материала, стабилизируют переменную магнитную индукцию в материале в зоне возбуждения и демпфируют упругие’.колебания до устранения зависимости затухания от величины подмагничивающего поля.This goal is achieved by the fact that according to the method of monitoring ferromagnetic materials, which consists in the fact that the material is magnetized by a constant field, elastic waves are excited in it, the vibration frequency is changed, the acoustic signal is recorded at the resonance frequency of these oscillations, the dependence of the amplitude of this signal on the magnitude of the magnetizing field is determined and according to the magnitude of the magnetizing field corresponding to the maximum amplitude of the acoustic signal, judge the properties of the material, stabilize the variable magnetic w induction in the material in the excitation zone and damp uprugie'.kolebaniya to eliminate attenuation depending on the magnitude of the magnetizing field.

II

На фиг. 1 представлены кривые зависимости добротности от подмагничивающего поля Но при разной степени демпфирующего воздействия на образец. Кривая Ополучена в недемпфированном состоянии, · кривые δ , A, Ζ - в демпфированном (по мере роста номера кривой растет демпфирующее воздействие). На фиг. 2 представлены зависимости нормированной по максимуму амплитуды акустического сигнала на частоте резонанса упругих колебаний в материале от подмагничивающего поля Но. Кривая д соответствует случаю отсутствия стабилизации переменной магнитной индукции в э<Ьне возбуждения недемпфированного образца, кривая в наличию стабилизации при демпфировании образца, устраняющем зависимость Q от Но. На фиг. 3 приведена схема реа-< лизании способа, содержащая последовательно соединенные амперметр 1 и соленоид ,2 подмагничивания, образец 3 исследуемого материала, расположенные на нем излучающий и приемный электромагнитноакустические (ЭМА) преобразователи 4 И 5, вспомогательную проходную катушку 6, охватывающую сечение образца в зоне под преобразователем 4, демпфирующие накладки 7 и 8, прикрепленные в местах пучностей колебаний образца 3 (распределение узлов и пучностей колебаний по длине образца показано пунктиром), тенератор 9 качающейся частоты, выход которого соединен с входом излучающего ⁵⁵преобразователя, частотомер 10, блок 11 автоматической регулировки амплитуды, подключенный к катушке 6, измеритель амплитудно-частотных характеристик, первый вход которого подключен к выходу приемного преобразователя 5, а второй к выходу генератора 9 качающейся частоты, и вольтметр 13, подключенный к выходу приемного преобразователя 5.In FIG. Figure 1 shows the curves of the Q-factor versus the magnetizing field Ho at different degrees of damping effect on the sample. Curve Received in an undamped state, · curves δ, A, Ζ - in a damped state (as the curve number grows, the damping effect increases). In FIG. Figure 2 shows the dependences of the maximum normalized amplitude of the acoustic signal at the resonance frequency of elastic vibrations in the material on the magnetizing field Ho. Curve g corresponds to the case of the absence of stabilization of variable magnetic induction in the excitation of an undeamped sample, the curve in the presence of stabilization during damping of the sample, eliminating the dependence of Q on Ho. In FIG. 3 shows a diagram of the method implementation, which contains a series-connected ammeter 1 and a solenoid, 2 magnetizations, sample 3 of the test material, emitting and receiving electromagnetic-acoustic (EMA) transducers 4 and 5 located on it, an auxiliary passage coil 6 covering the sample cross section in the zone under the transducer 4, damping pads 7 and 8, attached in places of the antinodes of the oscillations of the sample 3 (the distribution of nodes and antinodes of the vibrations along the length of the sample is shown by a dotted line), the oscillator 9 of the oscillating frequency, the output of which is connected to the input of the transmitter ⁵⁵ emitting, a frequency meter 10, an automatic amplitude control unit 11 connected to the coil 6, an amplitude-frequency characteristics meter, the first input of which is connected to the output of the receiving converter 5, and the second to the output of the oscillating frequency generator 9, and a voltmeter 13, connected to the output of the receiving transducer 5.

Способ реализуется следующим образом.The method is implemented as follows.

Образец 3 с раположенными на нем излучающим и приемным ЭМА преобразователями 4 и 5, вспомогательной проходной катушкой ^z 6 и демпфирующими накладрами 7 и 8 подмагничивают в соленоиде 2 постоянным магнитным полем, величину Но которого оценивают с помощью амперметра 1. В излучающий преобразователь 4 от генератора 9 качающейся частоты подают высокочастотное напряжение V и, варьируя частоту колебаний, с помощью измерителя 12 амплитудно-частотных характеристик определяют резонансную частоту образца 3, контролируя ее частотомером 10. Индуцируемый во вспомогательной катушке 6 сигнал обратной связи подают на вход блока 11, подключценного к генератору 9 качающейся частоты и автоматически регулирующего входе преобразователя 47 Резонансный акустический сигнал регистрируют приемным преобразователем 5, измеряют его амплитуду g, вольтметром 13 и наблюдают этот сигнал на экране измерителя амплитудно-частотных характеристик, случае двойного (излучение и прием) ЭМА преобразования iSample 3 with emitting and receiving EMA transducers 4 and 5 located on it, an auxiliary passage coil ^z 6 and damping plates 7 and 8 are magnetized in the solenoid 2 by a constant magnetic field, the value of But is estimated using ammeter 1. To the emitting transducer 4 from the generator 9 oscillating frequency serves a high-frequency voltage V and, by varying the frequency of oscillations, using the meter 12 of the amplitude-frequency characteristics determine the resonant frequency of sample 3, controlling it with a frequency meter 10. Induced during auxiliary coil 6, the feedback signal is fed to the input of block 11, connected to the oscillating frequency generator 9 and automatically regulating the input of the transducer 47. The resonant acoustic signal is recorded by the receiving transducer 5, its amplitude g is measured by a voltmeter 13, and this signal is observed on the screen of the amplitude-frequency characteristics meter , case of double (radiation and reception) EMA conversion i

/1 г где Θ- затухание упругих колебаний, складывающееся из 0_П - затухания, обусловленного потерями на излучение в окружающую среду, и 9&- затухания, обусловленного внутренними потерями в материале ( магнитомеханическим затуханием, зависящим от Но), /J кслк - кажущаяся магнитная проницаемость, представляющая собой пульсационную магнитную про. нииаемость, усредненную по скин-слою в зоне ЭМА преобразования,/Э^овр^ \“5н обратимая магнитострикционная восприимчивость материала при фиксированном механическом напряжении (Г . У средне и высокоуглеродистых сталей Q / слабо зависит от Но, и форма зависимое'ти ¢. = if (Но) в. общем повторяет форму зависимости ί ЭН ^? что позволяет вести контроль структурного сос-/ 1 g where Θ is the attenuation of elastic vibrations, consisting of 0 _P - attenuation due to losses due to radiation into the environment, and 9 & - attenuation due to internal losses in the material (magnetomechanical attenuation, depending on Ho), / J csl - apparent magnetic permeability, which is a pulsating magnetic pro. yieldability averaged over the skin layer in the zone of EMA conversion, / E ^ ovr ^ \ “5n reversible magnetostrictive susceptibility of the material at a fixed mechanical stress (G. For medium and high carbon steels Q / weakly depends on Ho, and the shape is dependent on these. = if (But) in general repeats the form of the dependence ί EN ^?, which allows one to control the structural

В тояния этих материалов по параметрам, определяемым из зависимости £ - у (Но), и, в частности по - величине подмагничивающего пспя, соответствующей максимуму амплитуды акустического сигнала £ . Однако в случае магнитомягких материалов_Кажи & существенно зависят от Но (кривая α. ί, в на фиг. 1, кривая Q на фиг. 2), что приводит к нарушению подобия зависимостей £= (Р(Й_О) *0 и,(ЭАоБр Л⁷¹⁵¹ предельного случая'магнитомягкого материала вообще не-, возможно определить Ho_wax по зависимости 6 - Ψ (Но), так как вместо острого)^ максимума на кривой £= ψ* (Но) имеет место горизонтальная площадка (кривая S на фиг. 2).The melting of these materials in terms of the parameters determined from the dependence £ - y (Ho), and, in particular, in the magnitude of the magnetizing PSI, corresponding to the maximum amplitude of the acoustic signal £. However, in the case of soft magnetic materials, _Kaj and _k substantially depend on Ho (curve α. В, in Fig. 1, curve Q in Fig. 2), which leads to a violation of the similarity of the dependences = = (P ( _{О 0} ) * 0 and, (EAoBr Л ^{7151 of the} limiting case of a soft magnetic material is not at all, it is possible to determine Ho _wax by the dependence 6 - Ψ (Ho), since instead of an acute) ^ maximum on the curve £ = ψ * (Ho) there is a horizontal platform (curve S on Fig. 2).

Однако поскольку/4 _ко* определяется . переменной магнитной индукцией, то фиксирование независящего от Но значения усередненного по сечению объекта в зоне возбуждения с учетом скин-эффекта (эффективного) переменного магнитного потока приводит к отстройке влияния /1_ксвк*= (Wo)на £ - ?(Н_о)(фиг. 1). Фиксирование переменной магнитной индукции и достигается с помощью обратной связи, компенсирующей изменение переменного магнитного потока, обусловленное изменением Но, за счет автоматической регулировки амплитуды переменного напряжения U на входе излучающего ЭМА преобразователя.However, since / 4 _ko * is defined. variable magnetic induction, the fixing independent of but values userednennogo over the cross section of the object in the driving zone in view of the skin effect (efficacy) of the variable magnetic flux causes the detuning effect / 1 _VSWR to * = (Wo) at £ -? (H _o) ( Fig. 1). The fixation of the variable magnetic induction is achieved with the help of feedback, compensating for the change in the alternating magnetic flux due to the change in Ho, due to the automatic adjustment of the amplitude of the alternating voltage U at the input of the emitting EMA converter.

- Прикрепление к образцу в местах пучностей колебаний демпфирующих накладок 7 и 8, масса которых подбирается такой, чтобы &_n770g , позволяет отстроится от зависимости & от Но. В этом случае, учитывая, что, Θ -70/Q. _w ,Q=Q_MQ_e/(Q_M+QB)^s0M W ' и суммарное затухание или добротность Q определяются потерями . . на излучение в окружающую среду ·· и не зависят от Но (кривая г- на фиг. 1). ⁴⁵ - Attaching to the sample in places of antinodes of vibrations of the damping plates 7 and 8, the mass of which is selected such that & _n 770g, allows you to rebuild on the dependence of & on Ho. In this case, given that, Θ -70 / Q. _w , Q = Q _M Q _e / (Q _M + QB) ^s 0M W 'and the total attenuation or quality factor Q is determined by the losses. . on radiation into the environment ·· and are independent of Ho (curve d in Fig. 1). ⁴⁵

Одновременное применение фиксации переменной магнитной индукции при демп'^! 15^s фировании. образца позволяет получить зависимость Е- Ψ (Но), подобную зависимости (кривая & на фиг. 2), определить из нее. величину Ηθη,»*’ отвенающую £ п<ах^и позволяющую^ оценить структурное состояние образца. Предлагаемое изобретение позволяет повысить точность контроля и расширить область применения его на магнитомягкие материалы за счет отстройки от влияния изменений кажущейся магнитной проницаемости и затухания⁴упругих колебаний, на зависимость акустического сигнала от подмагничивающего поля.Simultaneous application of fixation of variable magnetic induction during dump ' ^! 15 ^s chamfer. of the sample allows us to obtain the dependence E - Ψ (Ho), a similar dependence (curve & in Fig. 2), to determine from it. value Ηθη, »* 'otvenayuschuyu £ n <^ s ^and allows to evaluate the structural state of the sample. The present invention allows to increase the accuracy of control and expand its scope to soft magnetic materials due to the detuning from the influence of changes in the apparent magnetic permeability and attenuation of ⁴ elastic vibrations, on the dependence of the acoustic signal on the magnetizing field.

Claims

(54) METHOD OF CONTROL OF FERROMAGNETIC 1 The invention relates to acoustic methods of nondestructive control and can be used in the metallurgical and metalworking industry to control the structural state of the Damyshmic magnetostatic characteristics of semifinished products and products with good technical and carbon-magnetic characteristics of semiproducts and products made from carbon and carbon materials and products made from carbon and metalworking magnetostatic characteristics of semiproducts and products made from carbon and carbon materials and products made of carbon and metal products that produce carbon and metal products for industrial and commercial use. The known method of controlling ferromagics and: 1 of these materials, in which in the presence of a constant magnetic field excites ultrasonic oscillations, register the signal induced on a special measuring coil placed in the antinode of pressure at the distance, and on the phase difference between the excited and induced signals judging on the mechanical properties of the product 1 The closest in technical essence to the invention is The control of ferromagnetic materials, which are spoiled by the fact that the material of the POP MATERIALS is magnetised by the constant field, excites elastic oscillations in it, changes the frequency of oscillations, registers the acoustic signal at the frequency of the resonance of these oscillations, determines the dependence of the amplitude of this signal on the magnitude of the magnitude of the oscillation of the oscillations, the magnitude of this signal, the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of this signal, the magnitude of this signal, the magnitude of this signal, the magnitude of the magnitude of the magnitude of the magnitude, the magnitude of this signal, the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of this magnitude, the magnitude of the magnitude of this signal , corresponding to the maximum amplitude of the acoustic signal, judged on the properties of the material The general disadvantages of the known methods is the low measurement accuracy x Characteristics of materials due to the influence of the magnitude of the magnetizing fell But the mechanical and magnetic characteristics of materials, in particular, the apparent magnetic permeability of the cavity, and the damping Q, (Q Q of elastic oscillations. In the case of a magnet of gcnh materials, the effect of HO on fl and C) is not therefore, it is imperative to establish the magnitude of the magnetized field corresponding to the maximum amplitude of the acoustic signal. The circuit of the invention is twisting the TOHHOCS of control and ensuring the possibility of controlling magnetically soft materials. The goal is achieved by the fact that, according to the method of counter-ferromagnetic materials, there, the material is magnetised with a constant field, excites elastic cobers in it, changes the oscillation frequency, records the acoustic signal at the resonance frequency of these oscillations, determines the amplitude dependence of this signal on the magnitude of the magnetized field and the magnitude of the magnetized field corresponding to the maximum amplitude of the acoustic signal, judge the properties of the material, stabilize the variable magnet full induction in the material in the field of excitation and damping of the ynpynie oscillations until the dependence of the damping on the magnitude of the magnetic field I is eliminated. In FIG. Figure 1 shows the curves of the quality factor versus the magnetic field of its field, But with varying degrees and & lpftruyuschego effects on the sample. Curve Received in the undamped state, curves d, Л, 1 - in dem 11 |||) u) ovans (as the number of the curve grows, dem grows (}) and the dependence on the maximum amplitude of the acoustic signal on The resonance frequency of elastic xyenes in the material from the field magnetic field No. Corresponding to the case of the absence of stabilization of a variable magnetic field in an exciting undamped sample, the presence of a stabilized sample upon damping the sample, eliminated the dependence of Q on Ho. Fig. 3 shows a scheme for the implementation of the method, containing the alternately connected ammeter 1 and solenoid .2 magnetization, sample 3 of the material under study, radiating and receiving electromagnetically acoustic (EMA) transducers 4 t 5 on it, auxiliary pass coil b, and wound up in the area under the transducer 4, the damping plates 7 and 8, adhered to the places of the oscillations of the sample 3 The distribution of the nodes and the antinodes of the oscillations according to the dagpshe of the sample is shown in dotted line), the generator 9 from the frequency, the output of which is connected to the input of the radiating converter, the frequency meter U, b approx 11 of the automatic amplitude adjustment connected to the coil 6, the meter 12 of amplitude-frequency characteristics, the first input of which is connected to the output of the receiving converter 5, and the second to the output of the generator 9 frequency, and a voltmeter 13 connected to the output of the receiving converter 5. The method is implemented as follows. Sample 3 with emissive and receiving EMA transducers 4 and 5, auxiliary drive coil 6 and damping overlays placed on it} 7 and 8 themselves are magnetically magnetised in solenoid 2 by a constant magnetic field, but the value is measured with a a mnepvieTpa 1. I and the radiation transducer 4 from generator 9 and frequency of supply high frequency voltage V and by varying the frequency of oscillation, using the meter 12 amplitude-frequency characteristics determine the resonant frequency of sample 3, controlling its frequency meter. The feedback signal induced in the auxiliary coil 6 is fed to the input of the block 11 connected to the generator 9 of the frequency generator and automatically regulating the input of the converter. The resonant acoustic signal is recorded by the receiver transducer 5, its amplitude g is measured. With a voltmeter 13, this signal is observed on the screen of the meter 12 amplitude-frequency characteristics. In the case of dual (emission and reception) EMA conversion C l -r, where 0 is the attenuation of elastic oscillations, consisting of 0 "- attenuation due to losses due to radiation into the environment, and - attenuation due to internal losses in the material (magnetomechanical attenuation, depending on Ho), / Jccc, which seems to have magnetic magnetic conductivity, which is a pulsating magnetic permeability, averaged over the skin layer in the EMA HfA zone formation, / EHO5V is reversible the magnitude of the material's delight with a fixed mechanical stress (H. In medium and high carbon steels weakly depends on Ho, and the shape depends on the axis. {.g If (But) in general repeats the shape of the EH dependence / and that the poet “does not control these structural materials by the parameters determined by the dependence - V (But and, in particular, by Hc, d - well, the magnetising field corresponds to the maximum amplitude of the acoustic signal g y, case of magnet materials, | ,, О significantly for hanging from Ho (curve and. “Y in in FIG. 1, the curve in FIG. 2), which leads to an increase in the similarity of the V () .oEg N dependencies. , c. For the sake of the magnet of the material, it is possible to determine Ho, Q according to the i-H (Ho) dependence, since instead of the bluff maximum on the tj curve (Ho) there is a horizontal junction (curve E in Fig. 2), However, since co, | 1 is determined by variable magnetic induction, fixing an object independent of the But value of the section-averaged p in the excitation zone, taking into account the skin effect (effective) of the variable map stream, leads to detuning the effect of ff (Yo) on C - “P (MO) (FIG. 1). The fixation of the variable magnetic induction is achieved by means of feedback compensating for the change in the variable magnetic flux caused by the change But, due to the automatic adjustment of the amperage of the alternating voltage VI at the input of the radiating EMA converter. Attaching to the sample in the places of the antinodes of oscillations damping incidents 7 and 8, the mass of which is chosen so that i & f, 7760, allows you to rebuild from the dependence of b on Ho. In this case, taking into account that, 0 is ic / q. Q QHQft / CQM + Oft) W and total attenuation. or the quality factor Q is determined by the losses of .-. radiation into the environment and does not depend on Ho (curve in FIG. 1). Simultaneous use of variable magnetic induction during de-coupling. the sample allows us to obtain the dependence E (But), which is similar to the dependence (curve in Fig. 2), to determine the other value, which corresponds to allowing the assessment of the structural state of the sample. The present invention allows to increase the accuracy of control and to expand the field of its application to magnetically soft materials due to the detuning from the influence of changes in the apparent magnetic permeability and attenuation of elastic oscillations; on the dependence of the acoustic signal from the magnetizing floor. Claims The method of controlling ferromagnetic materials is that the material is magnetized by a constant field, excites the other oscillations in it, changes the frequency of oscillations, and records the acoustic signal on the part. the resonance of these oscillations, determine the dependence of the amplitude of this signal on the magnitude of the magnetising magnetic field, and the magnitude of the magnetising field corresponding to the maximum amplitude of the acoustic signal is judged on the properties of the material, characterized by the fact that, in order to increase the accuracy of the counter and ensure the control of magnetic materials, it stabilizes The alternating magnetic induction in the material in the excitation zone is damped by the elastic oscillations, to the removal of the dependence of the attenuation on the magnitude of the magnetic field. Sources of information taken into account during the examination 1. USSR author's certificate fe 552553, cl. Goin 29 / Jpo, 1977.

2. KoMapfffi V. A., Kuznetsov I. D., Akipga N. I., and others. Monitoring the thermal treatment of structural steel of the HOF by an electromagnetic method. - Defectoscopy, 1981, No. 2, p. 41-47 tfotkp). 20 30 40 Fi8.1 OJ50, 50055 But globally P08.2 t-- d xy HO, / cm 50 60. But // see

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