SU970204A1 - Magnetic noise structuroscopy device - Google Patents

Description

(54) DEVICE FOR MAGNETOSCALE STRUCTURE

one

The invention relates to non-destructive testing of ferromagnetic materials and can be used in the automatic control of the physical and mechanical properties of steels.

A device for magnetic noise restructuring is known, comprising a series-connected low-frequency current generator, a magnet-noise converter, a high-pass filter, and an amplifier; indicator

The device has a low control accuracy due to the absence of a reference measurement channel.

Closest to the proposed device is a magnetically noise structured microscopic device. The device contains a low-frequency current generator, a serially connected measuring converter, a converter, a high-pass filter, an amplifier and an indicator, a reference channel consisting of a series-connected reference converter, a high-pass filter and amplifier 2.

The drawbacks of this device are low sensitivity, due to the fact that it is nagging. The magnetization reversal is just and in most measurements the bu 1et is different from the optimal one; the need to have a standard and a controlled sample on both sides of the primary converter, which is not always possible.

The aim of the invention is to improve the accuracy of control due to the high sensitivity of the device and the expansion of its field of application.

The goal is achieved by the fact that the device is equipped with a bias current regulator, one input of which

15 is connected to the output of the current generator, and the output is connected to the inputs of the measuring and reference transducers, the threshold unit, the input of which is connected to the output of the reference channel amplifier, and the output 20 to the second input of the magnetization current regulator.

Claims (2)

FIG. 1 shows a structural diagram of a device for magnetically noisy structure of turoscopy; in fig. 2 and 3 are graphs that show how the device works. The device contains a measuring channel consisting of a series-connected low-frequency current generator 1, a magnetizing current regulator 2, a transducer meter 3 with magnetizing and measuring windings, an RF filter 4, an amplifier 5, an indicator 6, a reference channel, consisting of connected reference converter 7 with magnetizing and measuring windings, RF filter 8, amplifier 9 and threshold unit 10. Moreover, the input of reference converter 7 is connected to the output of the magnetization current regulator 2, and The output of amplifier 9 through the threshold unit 10 is connected to the control input of the regulator 2 of the magnetizing current. The primary transducer 3 is mounted on a test sample, this triple transducer 7 is installed on the reference device. The device operates as follows. The magnetizing current from the current-low-frequency generator 1 flows through the current regulator 2-magnetized to converters 3 and 7. The EMF of the sound from the output of the reference converter 7 through the RF filter 8, the amplifier 9 and the threshold unit 1O goes to the control input of the current regulator 2 magnetization. At the same time, the operating current of the converters 3 and 7 decreases to the value, with the EMF copier of the head of the reference sample at the output of the amplifier 9 is equal to the threshold voltage set at block 10. In this case, the sensitivity of the measuring channel will be close to maximum. The dependence of the EMF sensitivity of the Shuma 5 to internal voltages on the magnitude of the magnetizing current of the converter is shown in FIG. 2. With decreasing current, the sensitivity of the EMF noise to internal voltages increases. The dependence of the sensitivity of the EMF of the schum to the structure on the magnetizing current has the same character. The EMF of the noise from the output of the primary converter 3 through the RF filter 4 and the amplifier 5 is fed to the indicator 6. The indications Ep of the indicator will be determined by the magnetic noise properties of the test sample and are in close to linear dependence on the magnetizing current (Fig. 3). The magnetizing current due to the presence of feedback from the output and the amplifier 9 of the reference channel through the threshold unit 10 to the regulator 2 of the magnetizing current will be less than. 4 better magnetic noise properties of the reference sample, i.e. The indications Ep of indicator b will be determined by the ratio of the magnetic noise properties of the test and reference samples. It can be shown that Ep depends on the emf of EC of the noise of the control sample and the emf of the schum of the reference sample. The dependence of the emf of noise on the magnetizing current J, in a fairly wide initial region, is close to linear (Fig. 3). Based on this ; (one) . L, (2). ACh- KATA-, - coefficient characterizing. properties of the controlled sample; - transmission coefficient of the measuring channel; n is the coefficient characterizing the properties of the reference sample; - transfer ratio of the reference channel; 3 - the operating current of the converters 3 The converters 3 and 7 are connected to the magnetization current controller so that the currents of the converters are equal. Substituting the value of the current from (2) into (1), we obtain r –Ah c .. And at where K, K d are constant values; The EMF of the noise at the output of amplifier 9, due to feedback from the output of amplifier 9 through a threshold device to the control input of the magnetization unit, will also be equal to the constant value. The indications Ep of indicator 6 are determined by the prediction of the coefficients A and A, which characterize the magnetic noise properties of the test sample and the reference one (not shown), and the operating current of the primary converters will always be close to optimal due to the feedback effect. The advantages of the proposed device over the known are: higher sensitivity (when monitoring internal voltages, the sensitivity increases by 3-4 times), since the operating current decreases to a value close to due to the presence of a feedback circuit. optimal; there is no need to locate a standard and a controlled sample in a row, which is not always possible, for example, with comparative control of different areas of one sample, with control of large-sized samples or with control of products of complex shape; the device is rebuilt when changing the reference sample to the optimal mode, which allows its use in automatic control systems. Claims An apparatus for magnetic noise-noise structure analysis, comprising a low-frequency current generator, a serially connected measuring transducer, a high-pass filter, an amplifier and an indicator, a reference channel consisting of a series-connected reference transducer, a high-pass filter and an amplifier, characterized in that In order to improve the accuracy of the coitrol, it is equipped with an over-) magnetization current regulator, one input of which is connected to the output of the current generator, and the output is connected to the measurement inputs tionary and reference transducers threshold luster input coupled to the output of the reference channel, and output - k second input of the current regulator peremagnychivani torus. Sources of information taken into account in the examination 1. GDR patent number 94711, cl. Q 01 N 27/72, 1972. 2. USSR author's certificate Nb 670879, cl. Q OlN 27/86, 1979 (prototype).