SU1259173A1 - Method for checking physico-mechanical properties of ferromagnetic articles - Google Patents

Abstract

The invention of OTICOCHTCH to non-destructive testing and can be used to control the quality of ferromagnetic products. Improving the accuracy of controlling the physicomechanical properties of ferromagnetic products is achieved by reducing the effect on the control of the magnetomechanical attenuation of the signal. When a ferromagnet is neglected (Barkhausen pumas cause the formation of acoustic oscillations. The latter are recorded by a piezoelectric transducer located outside the zone of remixing. Il. § (L about 4J with

Description

one

The invention relates to the control of measuring equipment and can be used for non-destructive control; physicomechanical properties of products made of ferromagnetic materials, such as internal stresses, hardness and strength,

The purpose of the invention is to increase the accuracy of controlling the physicomechanical properties of ferromagnetic products by reducing the effect on the control of the magnetomechanical attenuation of the signal from Barkgausen noise.

The drawing shows a block diagram of the device control physical and mechanical properties of ferromagnetic products that implements the method of control.

The device includes a low-frequency current generator 1, coupled with an electromagnet 2, a piezo transducer 3, a broadband amplifier 4, a measurement unit 5, and a source 6 of a biasing electromagnet current.

The essence of the method is. That, when the ferromagnet is changed, the Barkgausen noise arises due to the irreversible processes of the domain wall motion. These processes, through the magnetostriction effect, are converted into Warkhausen acoustic noise signals, which are recorded by a piezoelectric transducer. Acoustic noise waves of Barkhausen propagate along a ferromagnet and can be detected by a piezoelectric transducer in areas remote from the excitation zone. However, acoustic waves decay in the volume of a ferromagnet. This attenuation 0 of acoustic oscillations is made up of acoustic attenuation 9 ij and magnetomechanical,. QQ does not depend on the magnetic state of a ferromagnet and is determined by its structural properties. ) (determined by the magnetic state of the ferromagnet, in particular, the losses on eddy currents and hysteresis of the capacitors.

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The method is carried out as follows.

A current of the generator 1 is washed down by the reelinitiating coil of the electromagnet 2, the field of which excites Barkgausen noise in the area of the magnetization reversal of the ferromagnetic product. Noise through the magnetostriction mechanism

Barkhausen is converted into acoustic waves, which are recorded by a piezoelectric transducer mounted on a specific part of the product, remote from the excitation wave. The acoustic Barkhausen noise amplifiers are amplified by an amplifier 4, the lower frequency of which is selected to filter out low-frequency noise and the remix and harmonics. Measurement unit 5 analyzes the acoustic signal of the Barkhausen noise and determines the result of the control based on a predetermined correlation dependence.

In order for the acoustic signal of the Barkhausen noise to not decay in the volume of the ferromagnet, it is premagnetized until it is filled with the current of source 6. At the same time, the power of the generator 1 is chosen from the condition of the remaking of the Barkhausen noise section of the product at the limiting hysteresis.

Formula and 3 b rynI.

The method of controlling the physicomechanical properties of ferromagnetic products, which consists in reversing the controlled product, registering acoustic signals due to Barkhausen noise using a piezo transducer, and determining the parameters of the control that differ from control accuracy, preliminarily magnetize the entire product to saturation, and acoustic signals register

in areas of the product located outside of the magnetization reversal zone.

Editor N. Dumbass

Compiled by P. Shkatov Tehred I.Veres

Order 5115/42 Circulation 778 Subscription

VNIIPI USSR State Committee

for inventions and discoveries Y3035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Proofreader M. Sharoshi

Claims (1)

Form street and sample. I A method for controlling the physicomechanical properties of ferromagnetic products, namely, that the controlled product is magnetized, register acoustic signals caused by Barkhausen noise with the help of a piezoelectric transducer, and determine the result of the control by their parameters, which is different in order to increase the accuracy of control , pre-magnetize the entire product to saturation, and acoustic signals are recorded on areas of the product located outside the magnetization reversal zone.