SU905772A1

SU905772A1 - Method of ferromagnetic article checking

Info

Publication number: SU905772A1
Application number: SU792793447A
Authority: SU
Inventors: Михаил Иосифович Майзенберг; Михаил Данилович Каплан; Владимир Ушерович Мошкович; Владимир Тимофеевич Бобров
Priority date: 1979-07-09
Filing date: 1979-07-09
Publication date: 1982-02-15

Description

Изобретение относится к контрольно-измерительной технике и может быть использовано для дефектоскопии изделий из ферромагнитных материалов.The invention relates to instrumentation and can be used for inspection of products from ferromagnetic materials.

Известен способ дефектоскопии намагничивающихся изделий, заключающийся в том, что изделие намагничивают, возбуждают в нем ультразвук заданной поляризации и регистрируют электромагнитные поля, возникающие над дефектной зоной [1 ],A known method of defectoscopy of magnetizable products, which consists in the fact that the product is magnetized, excite ultrasound in it of a given polarization and register electromagnetic fields arising above the defective zone [1],

Недостатком способа является его низкая чувствительность.The disadvantage of this method is its low sensitivity.

Наиболее близким по технической сущности к изобретению является способ контроля ферромагнитных изделий, заключающийся в том, что изделие намагничивают, воздействуют на него переменным полем электромагнитноакустического (ЭМА) преобразователя и регистрируют ультразвуковые сигналы, возникающие при наличии дефектов. Этот способ обладает высокой чувствительностью [ 2 ].Closest to the technical nature of the invention is a method of monitoring ferromagnetic products, which consists in the fact that the product is magnetized, exposed to it with an alternating field of an electromagnetic-acoustic (EMA) transducer and ultrasonic signals that occur when defects are detected. This method has high sensitivity [2].

Для данного способа характерна недостаточно высокая достоверность контроля вследствие низкой помехозащищенности.This method is characterized by insufficiently high reliability of control due to low noise immunity.

Цель изобретения - повышение достоверности контроля.The purpose of the invention is to increase the reliability of control.

Эта цель достигается тем, что в изделие вводят ультразвуковым преобразователем упругие импульсы, осу₁₀ ществляют каждым из преобразователей прием упругих импульсов, возбужденных другим преобразователем, и судят о наличии дефекта по одновременному появлению принятых сигналов на U обоих преобразователях.This goal is achieved by the fact that elastic pulses are introduced into the product by an ultrasonic transducer, _{10 that} each of the transducers receives elastic pulses excited by the other transducer, and the presence of a defect is judged by the simultaneous appearance of the received signals on U of both transducers.

На чертеже показана схема реализации способа.The drawing shows a diagram of the implementation of the method.

На чертеже обозначено: полюсные наконечники 1 намагничивающего уст20 ройства, между которыми помещено изделие 2, ультразвуковой преобразователь 3, например пьезоэлектрический, к преобразователю 3 подключен генератор 4 и приемный усилитель 5» надThe drawing indicates: the pole pieces 1 of the magnetizing device 20, between which the product 2 is placed, an ultrasonic transducer 3, for example a piezoelectric transducer, a generator 4 and a receiving amplifier 5 ”are connected to the transducer 3

905772 4 дефектом находится ЭМА преобразователь 6, который соединен с генератором 7 и усилителем 8, выходы усилителей 5 и 8 подключены к блоку 9 совпадения, выход которого подклю- 5 чен к индикатору 10.905772 4 the defect is the EMA converter 6, which is connected to the generator 7 and the amplifier 8, the outputs of the amplifiers 5 and 8 are connected to the coincidence unit 9, the output of which is connected to the indicator 10.

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

С помощью генераторов 4 и 7 одновременно создают импульсы в пре- ιο· образователях 3 и 6. При наличии дефекта над преобразователем 6.поле в зоне его расположения искажается и в этом месте происходит возбуждение упругого импульса, а через вре- is мя, равное времени прохождения ультразвука от преобразователя Здо расположения преобразователя 6, с помощью последнего принимают этот сигнал. Одновременно преобразователем 3 20 принимают сигнал от преобразователя 6. Сигналы преобразователей подают на усилители 5 и 8, а с них - на • блок 9 совпадения, с которого - на индикатор 10, фиксируя тем самым нал и-25 чие дефекта. При отсутствии дефекта под преобразователем 6 принятых сигналов не возникает и на индикаторе 10 не появится никаких отметок. ЭМА преобразователем 6 возбуждают и принимают упругие колебания лишь тогда, когда в зоне его действия за счет попадания в нее дефекта происходит искажение первоначального магнитного поля, которым намагничено изделие 2. ₃₅ Using the generators 4 and 7, they simultaneously create pulses in the transducers 3 and 6. If there is a defect above the transducer 6. the field in the area of its location is distorted and an elastic pulse is excited in this place, and after a time equal to time the passage of ultrasound from the transducer to the location of the transducer 6, using the latter receive this signal. At the same time, the converter 3 20 receives the signal from the converter 6. The signals of the converters are fed to the amplifiers 5 and 8, and from them - to the coincidence unit 9, from which - to the indicator 10, thereby fixing the presence of a defect. If there is no defect under the transducer 6, the received signals do not appear and no marks appear on the indicator 10. EMA transducer 6 excite and accept elastic vibrations only when in the area of its action due to the ingress of a defect there is a distortion of the initial magnetic field, which magnetized the product 2. ₃₅

Ультразвуковым же преобразователем 3 осуществляют эти операции независимо от наличия таких искажений поля. Для выполнения указанных условий первоначальное поле и геометрию ЭМА преобразователя 6 выбирают так, чтобы без дефекта преобразование не возникло.Ultrasonic transducer 3 carry out these operations regardless of the presence of such field distortions. To fulfill these conditions, the initial field and the geometry of the EMA of the transducer 6 is chosen so that no transformation occurs without a defect.

Таким образом, при появлении дефекта вблизи преобразователя 6 на ., нем возникает сигнал от приема импульса, излученного ультразвуковым преобразователем 3, а на последнем возникает сигнал от приема того импульса, который при наличии дефекта возбужден ЭМА преобразователем 6. Поскольку оба ультразвуковых импульса проходят в изделии одинаковый путь, то при одновременном запуске генераторов 4 и 7, питающих преобразователи 3 и 6, принятые импульсы должны появиться на них также одновременно. Благодаря этому о наличии дефекта судят по временному совпадению обоих принятых сигналов, что значительно повышает помехоустойчивость, поскольку вероятность одновременного появления помехи на обоих преобразователях мала.Thus, when a defect appears near the transducer 6 on., It receives a signal from the reception of the pulse emitted by the ultrasonic transducer 3, and at the last there is a signal from the reception of the pulse that, in the presence of a defect, is excited by the EMA transducer 6. Since both ultrasonic pulses pass in the product the same way, then with the simultaneous start of the generators 4 and 7, feeding the converters 3 and 6, the received pulses should appear on them also at the same time. Due to this, the presence of a defect is judged by the temporal coincidence of both received signals, which significantly increases the noise immunity, since the probability of simultaneous interference on both converters is small.

Claims

the defect is the EMA converter 6, which is connected to the generator 7 and the amplifier 8, the outputs of the amplifiers 5 and 8 are connected to the coincidence unit 9, the output of which is connected to the indicator 10. The method is implemented as follows. With the generators, k and J simultaneously generate pulses in transducers 3 and 6. If there is a defect over the transducer 6. The field in its area of location distorts and in this place an elastic pulse is excited, and after a time equal to the time of ultrasound transducer from TO 3 the location of the transducer 6, with the help of the latter take this signal. At the same time, the converter 3 receives a signal from the converter 6. The signals of the converters feed the amplifiers 5 and 8, and the signals from them - to the block 9 - coincidence, from which - to the indicator 10, thereby fixing the defect. If there is no defect under the converter 6, no received signals appear and there are no marks on the indicator 10. The EMA transducer 6 excites and accepts elastic oscillations only when, in the area of its action, due to the ingress of a defect, the original magnetic field is distorted by which the product 2 is magnetized. However, the ultrasonic transducer 3 performs these operations irrespective of the presence of such field distortions. These conditions, the initial field and the geometry of the EMA transducer 6 is chosen so that a transformation does not occur without a defect. Thus, when a defect appears near the transducer 6, a signal arises from the reception of an impulse emitted by the ultrasonic transducer 3, and at the last there is a signal from the reception of the pulse that, in the presence of a defect, is excited by the EMA transducer 6. Since both ultrasonic pulses pass through If the generators and the 7 supplying pre-phasers 3 and 6 are simultaneously started, the received pulses must appear on them at the same time. Due to this, the presence of a defect is judged by the temporary coincidence of both received signals, which significantly increases the noise immunity, since the likelihood of simultaneous interference on both transducers is small. Claims The method of controlling ferromagnetic products, namely, that the product is magnetized, is acted upon by a variable field of an electromagnetic-acoustic transducer, and ultrasonic signals occurring in the presence of defects are recorded, characterized in that, in order to increase the reliability of cont. In this case, elastic pulses are introduced into the product by an ultrasonic transducer, each transducer is receiving elastic pulses excited by another transducer, and a defect is detected by the simultaneous appearance of received signals on both transducers. Sources of information taken into account during the examination 1. The author's certificate of the USSR for application tf 2373097 / 25-28, cl. G 01 N 29/0, 1976.

2. USSR Author's Certificate in Application N ° 2530535 / 25-28, cl. G 01 N 29/0, 1977 (prototype).

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