SU1453308A1 - Magnetotelevision flaw detector - Google Patents

Abstract

The invention relates to non-destructive testing of materials and products and can be used to control the quality of ferromagnetic products by visualizing the distribution of magnetic fields. The aim of the invention is to increase the accuracy and productivity of the control by optimizing the magnetization mode and automating the scanning direction. When monitoring the product, the magnetosensitive unit 2 converts the distribution of magnetic fields in the product into an electrical signal, the value of which is indicated by the luminous intensity of the screen of the video monitor unit 4. To select the optimal direction of the magnetization vector, the measurement and optimization unit 5 measures the magnetization current and controls the generator 6 pr variable frequency pulses and a binary counter. 7. The level of optimization informs the signal coming from the output of the amplitude selector 3. 2 Il. (Oh (L

Description

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The invention relates to the field of nondestructive testing of materials and products and can be used to control the quality of ferromagnetic products by visualizing the distribution of magnetic fields.

The aim of the invention is to improve the accuracy and productivity of the control by optimizing the magnetization mode and automating the scanning direction.

Figure 1 shows the block diagram of the magnetotelevision flaw detector j in figure 2 - signal plots at the test points.

The flaw detector contains a series-connected sweep unit 1, a magnetically sensitive unit 2, an amplitude selector Z. and a video monitoring unit 4, the synchronization input of which is connected to the sweep unit 1.

The flaw detector also contains serially connected measurement and optimization unit 5, connected to the output of the amplitude selector .3, a variable frequency generator of 6 rectangular pulses, a binary counter 7 whose second input is connected to measurement and optimization unit 5, a resistive matrix converter R, amplifier 9 power, the output of which is connected to the second input of the unit 5 measurements and optimization, and the electromagnet 10.

. Magnetotelevision flaw detector works as follows.

The control object 11 is magnetized with the help of an electromagnet 10. The non-uniform field of the control object 11 acts on the magnetically sensitive node 2, changes the output signals of the magnetic sensitive elements, and on the screen of the video control unit 4 shows an optical image corresponding to the magnetic relief of the control object 11, thanks to synchronous sweep of the beam carried out by block 1 sweep. The inhomogeneity of the magnetic field of the control object 11 is due to magnetic fields scattered from defects. The brightness of the light spot on the screen of the video monitor unit 4 is adjusted by means of an amplitude selector 3.

The signal from the amplitude selector 3 is fed to the first input of the measurement and optimization unit 5, from the first output of which the control voltage

positive or negative polarity (Fig. 2a) is applied to the control input of the generator 6 rectangular pulses of variable frequency, increasing or decreasing the frequency of the output signal (Fig. 26). If the signal at the output of the amplitude selector 13 (Fig. 2 (5d) is not sufficient to ensure; O: no qualitative image of the defect: on the screen of the video control unit; 4, the control output of the first measurement and optimization unit 5 appears positive 2) (Fig. 26), which increases the frequency of the signal in the code (Fig. 2) and the angle of rotation of the magnetization vector. But as the frequency of the AC current increases, the inductive

0 the resistance of the windings of the electromagnet 10. This reduces the amplitude of the current and, accordingly, the amplitude of the magnetizing flow. As a result, even with the optimal direction of the magnetization vector of the magnet, its value may be insufficient to provide a high-quality image of the defect on the screen of the video monitoring unit 4. To the second input of the measurement unit 5

Q and optimize the signal from the amplifier 9 power. This is necessary to introduce a correction for the change in the amplitude of the supply current. The magnitude of the current supplying the windings of the electromagnet 10 is measured using the measurement and optimization unit 5, and with a significant decrease in amplitude from the second output of the measurement unit 5 and optimization, the positive polarity signal is fed to the control input of the binary counter 7 (FIG. 2e), increasing the number of steps at the output of the binary counter 7 and the amplitude of the current supplying the electromagnet 10 to a predetermined value (figure 2). When the value of the signal at the output of the amplitude selector 3, the first threshold of sensitivity (Fig. 2c), the image quality of the defect on the screen of the video monitoring unit 4 is degraded. With

0 this, the first output of the measurement and optimization unit 5, appears a negative polarity signal (FIG. 25), reducing the frequency of the current (FIG. 2b), at the second output of the measurement and optimization unit 5: an AI signal appears also negative polarity (FIG. 2e), reducing the number of steps at the output of binary counter 7 and the amplitude pi5

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The formula of the invention is a magneto-television flaw detector containing a series-connected power amplifier and an electromagnet and a series-connected scanner, a magnetically sensitive node, an amplitude selector and a video monitoring unit, the synchronization input of which is connected to a sweep generator differing in.

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that, in order to improve the accuracy and performance of the control, it is equipped with a measuring and optimization unit connected in series, the inputs of each are connected to an amplitude selector and a power amplifier, a variable frequency square pulse generator, a binary counter, the second input of which is connected to the measurement and optimization unit, and a resistive matrix converter, the output of which is connected to the power amplifier.

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Claims (1)

Claim Magnetotelevision flaw detector, $ containing a serially connected power amplifier and an electromagnet and a serially connected scan unit, a magnetically sensitive ₁₀ node, an amplitude selector and a video control unit, the synchronization input of which is connected to a scan generator, characterized in that, in order to increase the accuracy and performance of the control, it is equipped with connected in series by the measurement and optimization unit, the inputs of each are connected to an amplitude selector and power amplifier, a direct generator ougolnyh variable frequency pulses, binary counter, the second input of which is connected to the power measurement and optimization, and a resistive matrix converter, whose output is connected to the power amplifier. Co-owner Y. Glazkov