SU1495730A1 - Method of measuring coercive remanence force of ferromagnetics - Google Patents

Abstract

The invention can be used for non-destructive testing of the physicomechanical characteristics of ferromagnetic materials, for example, for measuring the coercive force of the remanents of ferromagnets (FM). The purpose of the invention is to accelerate the measurement process. It is achieved by the fact that the FM magnetization is carried out by a combination of alternating and increasing constant magnetic fields (PMF), and the difference in the amplitude value of the intensity of the alternating and current PMF values is taken as the current value of the demagnetizing field. The increase in the values of the PMF intensity is carried out in the form of small increments, following synchronously with the frequency of the variable field. 1 hp f-ly, 3 ill.

Description

(21) 4133345 / 24-21

(22) 10/14/86

(46) 07.23.89. Bnsh. Number 27

(71) Tyumen Industrial Institute, Lenin Komsomol

(72) S.A. Musihnn

(53) 621.317.44С088.8)

(56) Sterkhov G.V., Yermolaev VOG, Tokunov.S. Quality control of high-temperature tempering of products from steels 30 ХГСА and 8ХФ in a closed circuit. - Defectoscopy, 1984, No. 7, SoZ-6.

(54) METHOD OF MEASUREMENT OF THE CENTER FORCE OF A CREAMER OF FERROMAGNETS

(57) The invention may be used for non-destructive testing.

. physicomechanical characteristics of ferromagnetic materials, for example, for measuring the coercive force of a ferromagnetic romance (FM). The purpose of the invention is to accelerate the measurement process. It is achieved by the fact that the FM magnetization is carried out by a combination of alternating and increasing constant magnetic fields (PMF), and as the current value of the demagnetizing field they take the difference of the amplitude value of the intensity of the alternating and current value of the PMF. The increase in the values of the PMF intensity is carried out in the form of small increments, following synchronously with the frequency of the variable field,. 3 ffl, 3 silt

The invention relates to magnetic measurements, and can be used for non-destructive testing of the physical and mechanical characteristics of ferromagnetic materials.

The aim of the invention is to accelerate the measurement process.

Fig and 1 shows the block diagram of the device that implements the method; figure 2 - timing charts, in mind, the operation of the device; FIG. 3 shows hysteresis loops that clarify the method,

A device that implements a method for measuring the coercive force of a ferromagnet remanent contains a trigger I, a generator 2 of a sinusoidal signal, a switch 3, an alternating current amplifier 4, a constant barrier filter 5 (capacitor), a choke 6, a DC amplifier 7 ( CNT), digital-analog converter (DAC) 8, counter 9, magnetizing winding 10, reference resistor 11 for measuring the magnetizing field, U-shaped sensor 12, assembled from electrical steel plates, induction sensor 13, measure l 14 induction, comparator 15 zero induction, one-shot 16 and 17, respectively, positive and negative induction, the element OR 18, comparator 19 zero-field, one-shot 20 and 21, respectively, positive and negative fields, the second element OR 22, element And 23, differentiator 24, comparator 25 ex4 JV

WITH

Torsomas floor, single vibrators 26 and 27, respectively, maximum and minimum extremes, analog-to-digital converter (ADC) 28, memory block 29, differentiating zieno 30, measured value indicator 31, controlled material 32 (FIG.).

The method is implemented as follows.

To start the measurement, a single pulse is fed to the trigger trigger 1 input (RS trigger), a single level of its output signal opens the key 3 and allows the sinusoidal signal from the generator 2 to pass through the amplifier 4 and the filter 5 of the obstacle to the coil 10 of the magnetization of the sensor 12 Amplifier 4 is chosen so that the variable component of the I-magnetising current leads the magnetic circuit of the sensor I2 and the monitored product 32 to saturation, i.e., the initial magnetization reversal of the material is carried out along the limiting loop hysteresis (Fig. 3). A reference proportional to the magnetizing current in the sensor coil 10 is removed from the reference resistor. A unit level of the trigger trigger 1 output signal is, through the differentiator element 30, clearing the memory block 29 and the counter of counter 9, resetting to zero through the digital signature module 8 the value of the output signal of the UFT 7. The induction in the magnetic circuit is measured by the induction sensor B (Hall sensor, ferrozond and TOD.), the useful signal of which is provided by the induction meter 14. A zero-induction comparator 15 converts a distorted sinusoidal signal proportional to the magnitude of the induction in the material into a rectangular shape. The one-way vibrator of positive induction produces a short pulse when the induction passes through zero from the negative to the positive, the one-shot 17 negative (FIG. 2, signal B (j) o Element OR 18 sums the short pulses of the one-shot 16 and 17 so that the output of the element 18 is a sequence of short pulses, respectively when the induction is equal to zero. The signal proportional to the magnitude of the resulting magnetizing field is divided into three channels: the first is the selection of the zero value of the resulting field, the second is the selection of the extrema of the resultant field, In the first channel the comparator is 19 zero the field using one-shot positive field 20 and negative field 21, the summing element OR 22 allows you to get a comb of pulses corresponding to the moments of the zero field, ana ogichno vscheleniyu moments zero induction. Element 23 allows to distinguish the time of coincidence in time of zero values of the field and induction. The second channel, through the differentiator 24, the comparator 25 of the extremes, the single-oscillators of the maximum extremum 26 and the minimum extremum 27, selects the points in time when the resulting field passes through the extremes. The third channel (our measurement) using a fast-speed A / D converter 28 performs a measurement of the resultant field using the minimum extremum single-oscillator 27 command, zeroes its readings at the command of the single-extremum single-oscillator 26, and when a single signal appears from the AND 23 element (coincidence in time, zero values (SRI field and induction) rewrites the output code of the A / D converter 28 into memory block 29. The contents of the memory are immediately transmitted to the indicator 31, In addition, the pulses of the one-shot 26 maximum field are taken into account by the counter 9 and using DAL 8 and TFT 7 are discretely converted to the value of a constant magnetizing current, thus linearly discretely increasing the magnetizing current and, consequently, the field of synchronization is the moment of maximum extremum, t, e each re magnetization cycle takes place with one bias current, the choke 6 is necessary in order to The laying field did not close due to the low output resistance of the UFT 7. The bias current is increased until the zero value of the induction and the resultant under match in time. The appearance of a single impulse at the output of the element And 23 also affects the trigger 1 of the trigger

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Claims (2)

Claim 1. A method of measuring the coercive force of the Riemannian ferromagnets, which consists in magnetizing it along the limiting hysteresis loop and demagnetizing to a field strength value, after removing which the value of the resulting residual induction of the ferromagnet is zero, and the corresponding value of the demagnetization field is taken as the coercive force of the re-1495730 manza, different in order to speed up the process 5 measurements, the magnetization of a ferromagnet is carried out by a combination of variable and increasing constant magnetic fields, and as the current value of the demagnetizing field take the difference in the amplitude value of the intensity of the variable and the current value of the constant magnetic fields, < 2 _O The method according to claim 1, characterized in that the increase in the values of the constant magnetic field is carried out in the form of small increments following synchronously with the frequency of the alternating field. Fig.