SU934400A1 - Device for testing parameters of ferromagnetic materials - Google Patents

Description

(5) DEVICE FOR CONTROL OF PARAMETERS OF FERROMAGNETIC MATERIALS

one

The invention relates to a measuring technique and can be used in the non-destructive testing of parameters of ferromagnetic materials and products from them.

A device for controlling the quality of materials is known, comprising an electromagnetic transducer, an amplifier, a comparison unit and an indicator. The operation of the device consists in extracting the Barkhausen jump signal, the average power of which is compared with the power of the same signal from the sample with known properties l.

A disadvantage of the known device is low control accuracy.

Closest to the proposed technical entity is a device for monitoring the parameters of ferromagnetic materials, containing a source of magnetization reversal and a series-connected electromagnetic transducer, amplifier, magnetic noise dispersion meter and indicator J.

A disadvantage of the known device is the low control accuracy,. caused by the influence of the dispersion of thermal noise, especially at small output signal levels and when the ambient temperature fluctuates.

The purpose of the invention is to improve the accuracy of control.

Claims (2)

The goal is achieved by the fact that the device for monitoring the parameters of ferromagnetic materials is equipped with series-connected detection units of the stationary state and memory and two keys connected to the output of the amplifier, the second key inputs are connected respectively to the outputs of the station detection units of the stationary station and memory, and outputs - with the corresponding inputs of the magnetic noise dispersion meter. 393 The drawing shows a block diagram of the device. The device contains a source 1 for magnetization of the sample 2, successively connected electromagnetic transducer 3, amplifier, detection unit 5 for detecting the non-stationarity section and memory block 6, two keys 7 and 8, one inputs of which are connected to the output of amplifier 4, and the second respectively to the outputs of the blocks 5 and 6i are connected in series with the meter 9 of the dispersion of magnetic noise, the inputs of which are connected to the outputs of the keys 7 and 8, and the indicator 10. The determination of the controlled pair Mejpa is carried out in two cycles. In the first step, a portion of non-stationarity is discovered and its duration is memorized. In this case, the dispersion of the mixture of the useful signal — magnetic noise and stationary thermal noise — is determined. In the second cycle, the duration of which is also equal to the duration of the nonstationary segment, the dispersion of thermal noise is subtracted from the obtained value of the dispersion. The device works as follows. Periodic transient noise, detected by the electromagnetic transducer 3 during periodic re-magnetization of the sample 2 by source 1 of the magnetization reversal, comes from the output of the amplifier C to the private keys 7, 8 and block 5 of detecting the section of non-stationarity. With the passage of noise at time t, the key 7 opens and a random signal, which is the sum of two processes, arrives at the direct dispersion meter 9. At the same time, the signal from the block 5 for detecting the non-stationarity section goes to the memory block 6, where the duration of the non-stationarity section t is memorized. After block 6 opens key 8 at time t key 7 closes. From the moment t, the stationary thermal noise arrives at the inverted input of the dispersion meter 9. In time 4 (2.b), the meter 9 estimates the dispersion of thermal noise and subtracts from the previously determined dispersion in the nonstationarity segment n (2) At time t, key 8 closes, indicator 10 records the result obtained. The use of the proposed device makes it possible to increase the accuracy of monitoring the parameters of ferromagnetic materials by eliminating the influence of the dispersion of thermal noise with a change in ambient temperature. An apparatus for monitoring parameters of ferromagnetic materials, containing a source of magnetization reversal and a series-connected electro-transformer, an amplifier, a measuring instrument for dispersing magnetic noise and an indicator, characterized in that, in order to achieve accurate control, it is equipped with successively connected blocks for detecting a portion of non-stationarity and a memory and two keys connected to the output of the amplifier; the second inputs of the keys are connected respectively to the outputs of the detection units of the section estatsionarnosti and memory, and outputs - to the corresponding inputs of the dispersion of the magnetic noise meter. Sources of information taken into account in the examination 1. GDR patent number 71635, cl. K2 46/06, 1968. I. . . 2. USSR author's certificate number 559193, cl. G 01 R 27/26, 1975 (prototype) 1 k / I H