SU1293621A1 - Device for non-destructive checking of stress anisotropy in ferromagnetic materials - Google Patents

Abstract

The invention relates to instrumentation technology using the Barkhausen effect. The aim of the invention is to improve the accuracy of control of the anisotropy of stresses in products with a magnetic texture induced by various types of surface technological strengthening treatments - is achieved. due to the compensation of interfering factors, in particular magnetic anisotropy. The information on the indicator 15 is presented as the dependence of the emf of the Barkhausen emf on the angle of rotation of the electromagnet 1 around the vertical axis 2. A system with negative feedback in amplitude of the magnetic induction in the product, including the induction measurement coil 6, the integrator 7, the memory block 8 and the block 9 control, maintains the constant of this parameter of the reversal in the process of turning the converter by controlling the current of the source 4. 2 Il. "G (L

Description

The invention relates to instrumentation technology and can be used to control the anisotropy of mechanical stresses in textured ferromagnetic materials, mainly in their surface layers.

The purpose of the invention is to improve the accuracy of control of stress anisotropy by maintaining the same mode for all directions of re-magnetization of ferromagnetic products.

FIG. 1 shows a block diagram of the device according to FIG. 2-time diagrams of signals, explaining the principle of operation of the device.

The device contains a P-type electromagnet 1 mounted rotatably around a vertical axis 2 on which the rotation angle sensor 3 (for example, a selsyn sensor) is located is connected in series with an alternating current source 4 and a winding 5 of the magnetization reversal of the electromagnet 1 connected in series with a catugac 6 induction measurement, wound on the magnetic conductor of the electromagnet 1, integrator 7, memory block 8, control block 9 connected to the second input of the alternating current source 4, the comparator 10 connected between Using a coil 6, a second input of the integrator 7, and a second input of the memory block 8, a reference voltage source 11 connected to the second input of the control block 9, the Barkhausen noise measurement coil 12, the amplifier 13, the band-pass filter 14 and the indicator 15, the second input of which connected to the sensor 3 angle.

The device works as follows.

An adjustable AC source 4 feeds the magnetising winding 5 of the electromagnet with a triangular current (Fig. 2q). In this case, the output signal of the measuring coil 6 (Fig. 25) is proportional to the rate of change of induction in the magnetic circuit of the electromagnet 1. This signal is fed to the input of the comparator 10, the output signal of which is shown in

, figs. 2 &. The zero output of comparator 10 unlocks the integrator 7 and the latter integrates the output signal of the measuring coil 6.

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A single output of comparator 10 blocks integrator 7 and sets it to its original zero state. Thus, the integrator 5 torus 7 integrates the output signal of the coil 6 in the time interval after which induction in the magnetic circuit of the electromagnet 1 is measured.

It is from + B to B, with the derivative dB / d-fc having the same polarity at the same time interval. It is obvious that the amplitude of the output signal of the integrator 7 is proportional to the value of 2B, i.e. maximum induction in the magnetic circuit of the electromagnet 1.

On the positive edge of the comparator 10, the amplitude of the output signal of the integrator 7 is stored by memory block 8, the output of which is shown in FIG. 2p. This output signal is fed to one input of control unit 9, to the second input of which the reference voltage is supplied from source 11. The amplified error signal between the reference voltage and the output signal of memory block 8 is fed to the control input of the adjustable source. 4 AC. If the maximum value of the induction in the magnetic circuit of the electromagnet 1 for any reason differs from the value determined by the voltage taken from the source 11 of the reference voltage, then the error signal acts on the adjustable AC source 4 so as to compensate for this difference. Since the transfer coefficient of block 9

memory unit 8 is set almost equal to the value of the reference voltage taken from source 11. In this case, the magnitude of the induction in the magnetic circuit of electromagnet 1 depends little on the magnetic characteristics of the magnetic circuit itself.

Thus, when turning electromagnet 1 with coils 5 and 6 in-p circle of axis 2, the induction amplitude in the material does not change. Only the parameters of the Barkhausen noise caused by the change in voltage change.

along different directions in a ferromagnet. In coil 12, an emf from barkhausen jumps occurs, which is amplified by an amplifier 13. With

bandpass filter 14 is made of one of the spectral components of the noise, which is fed to the first input of the two-coordinate indicator 15, to the second input of which a signal is proportional to the angle of rotation of the magnetic circuit 1 from the angle sensor 3. Consequently, indicator 15 will register a relationship characterizing the stress anisotropy curve in the controlled area of the product.

Thus, the device reduces the error in the control of the anisotropy of mechanical stresses by compensating for the error due to the anisotropy of the magnetic permeability occurring in the texturized ferromagnetic materials.

Claims (1)

Invention Formula A device for non-destructive testing of stress anisotropy in ferromagnetic materials, containing a U-shaped electromagnet, Editor A. Revin Phi. 2 Compiled by V. Filinov Tehred V. Kadar Order 379/48 Circulation 777 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 an rotatable around the longitudinal axis, an alternating current source connected to the magnetic reversal winding of an electromagnet, a Barkhausen noise measurement coil connected in series, an amplifier, a band-pass filter and an indicator, and a turn-relief sensor mounted on the axis of rotation and connected to an indicator different from that, in order to improve the accuracy of control of the anisotropy of stresses under a plane-stressed state, it is equipped with a series-connected integrator, a memory unit and a control unit not connected to the second input of the AC source, an induction measuring coil wound on an electromagnet magnet and connected to an integrator, a comparator connected between the induction measuring coil and the second integrator input, and a reference voltage source connected to the second input of the control unit and the second output of the comparator is connected to the second input of the memory unit. five 0 Proofreader G. Reshetnik