UA137259U - SEPARATE-COMBINED ELECTROMAGNETIC-ACOUSTIC CONVERTER FOR ULTRASOUND SURFACE WAVE PULSE CONTROL - Google Patents

Abstract

Separately combined electromagnetic-acoustic transducer for control of pulses of ultrasonic surface waves has a housing and fixed in it two sources of a constant magnetic field, two high-frequency inductors with linear working sections, which are made in a zigzag shape and placed in a high-frequency is exciting, and the second - registering, protector. Both high-frequency inductors are arranged in the same plane so that the linear working sections of the recording and excitation high-frequency inductors are located at a predetermined distance along an axis perpendicular to the direction of emission of ultrasonic pulses along the surface. In this case, the linear parts of the working sections of the excitation and receiving high-frequency inductors are oriented to each other at an angle of 120 ° ± 10 °. The excitation high-frequency inductor is shifted relative to the recording high-frequency inductor in the direction of radiation of surface wave pulses by the value of A, which is defined by the expression: A = A / 2, where λ is the surface wavelength excited in the controlled product

Description

The useful model belongs to the means of non-destructive testing and can be used to detect defects in metal products using ultrasonic pulses of Rayleigh waves.

Known |(1| contactless electromagnetic-acoustic (EMA) converters (EMAP) for excitation of surface wave pulses, which have a magnetic field source and high-frequency inductors, in which the exciting and receiving high-frequency inductors are serpentine in shape with working linear sections. Excitation and the reception of acoustic waves is implemented by using magnetic and electromagnetic fields, forming ultrasonic oscillations of a given frequency in the surface layer of the OK.

The disadvantage of this type of converter is insufficient reliability in detecting defects on the surface of the object of control (OC), which is due to the presence of coherent interference that occurs when the EMAP works with exciting serpentine high-frequency inductors.

The closest to the proposed one is the EMA converter (21), which has a case, magnetic field sources, high-frequency inductance coils, the linear sections of which are made in the form of a snake and a protector are placed in it.

The disadvantage of such an EMAP is that with this design of high-frequency inductors, ultrasonic pulses reflected from surface defects are received under the influence of coherent interference. The reliability of the control will not be sufficient.

The basis of a useful model is the task of creating an EMA converter, the new implementation of which would allow to increase the reliability of the detection of OK defects by reducing the effect of the bidirectionality of the acoustic field directional diagram and reducing the effect of coherent interference on the amplitude of the signal reflected from the defect.

The task is solved in a separate-coupled electromagnetic-acoustic transducer for controlling pulses of ultrasonic surface waves, which has a case and fixed in it two sources of a constant magnetic field, two high-frequency inductors with linear working sections, which are made in a zigzag shape and placed in a non-conductive non-ferromagnetic basis, one high-frequency inductor is exciting, and the other is recording, protector, both high-frequency inductors are placed in the same plane in such a way that the linear working areas of the recording and exciting high-frequency inductors are located at a given distance from each other along an axis that is perpendicular to the direction radiation of ultrasonic pulses along the surface of the product, while the linear parts of the working areas of the exciting and receiving high-frequency inductance coils are oriented to each other at an angle of 1207-10" according to a useful model, exciting high the low-frequency inductor is shifted in relation to the recording high-frequency inductor in the direction of radiation of surface wave pulses by the amount A, which is determined by the expression:

A Me, where A is the length of the surface wave that is excited in the material of the controlled product,

MM.

In Fig. 1 shows a schematic image of a separately-connected electromagnetic-acoustic transducer for control by pulses of ultrasonic surface waves and its placement on the OK.

In Fig. 1 marked: 1 - body; 2 and 3 - permanent magnetic field sources; 4 and 5 - high-frequency inductors; b - non-conductive non-ferromagnetic base; 7 - protector; 9 - object of control.

Fig. 2 shows the location of high-frequency inductors in the non-conductive non-ferromagnetic base of EMAP

In Fig. 2 are marked: 4 and 5 - high-frequency inductors; 8 - direction of radiation of ultrasonic pulses; HER is the distance between the exciting and recording coils of the inductance; A is the amount of displacement of the exciting high-frequency inductor relative to the recording high-frequency inductor.

EMAP works as follows. The EMAP, which has a body 1, is placed on the surface of the OK, as shown in Fig. 1 so that the protector 7 adjoins the surface of the OK 9. The source 2 of the constant magnetic field creates a polarizing magnetic field in the surface layer of the OK. Current pulses feed the exciting high-frequency coil 4 inductance. A high-frequency coil of 4 inductances generates an electromagnetic field. The guidance of magnetic and electromagnetic fields forms an alternating force on the surface of OK 7, which generates pulses of ultrasonic surface waves that spread along the surface in the direction indicated by arrow 8. The created acoustic field scans the surface of OK 7 with Rayleigh waves. The protector 7 protects the EMA converter 60 from damage during scanning of the OK 7 surface.

If there is a defect in the OK 7, then the ultrasonic pulses are reflected from it and reach the recording high-frequency coil 5 of the inductance, which is in the zone of action of the permanent magnetic field of the source 3. The interaction of the acoustic field of the pulse reflected from the defect and the permanent magnetic field leads to the appearance of an electromagnetic field under the recording high-frequency coil 5 of the inductance, which forms in the high-frequency coil 5 of the inductance a corresponding electric pulse that carries information about the defect. At the same time, due to the relative location of the high-frequency coils 4 and 5 of the inductance from each other at a distance I, the displacement of the high-frequency coils relative to each other by the amount A, as well as the orientation of the longitudinal parts of the EMAP high-frequency coils at an angle of 1207-10", the reception of coherent acoustic interference is excluded, which may be generated by other sections of the high-frequency inductor 4. In addition, the surface of the OK 7 is scanned only in one part of it, which is in the region of the opening of the obtuse angle 1207210", which also reduces the reception of acoustic interference. As a result, the influence of coherent disturbances arising during the excitation of ultrasonic pulses on the magnitude of useful signals is significantly reduced.

The technical result of the useful model is that the converter of this design has high protection against coherent acoustic disturbances. As a result, the proposed converter increases the reliability of ultrasonic control of the surface of metal products by Rayleigh waves.

Sources of information: 1. Gordely V.I. Modern electromagnetic-acoustic converters for non-destructive testing / V.I. Gordely, V.E. Chabanov // Technical diagnostics and non-destructive control. - 2005. -Mo 2. - P. 59-60. 2. Suchkov H.M., Plesnetsov S.Yu., Meshcheryakov S.Yu., Yudanova N.N. New development of electromagnetic-acoustic transducers (review) //Technical diagnostics and non-destructive control. 2018. Mo. 3. P. 27-34.

Claims (1)

USEFUL MODEL FORMULA Separately coupled electromagnetic-acoustic transducer for control of pulses of ultrasonic surface waves, which has a housing and fixed in it two sources of a constant magnetic field, two high-frequency inductors with linear working areas, which are made in a zigzag shape and placed in a non-conductive non-ferromagnetic base , one high-frequency inductor is exciting, and the other is recording, protector, both high-frequency inductors are placed in the same plane in such a way that the linear working areas of the recording and exciting high-frequency inductors are located at a given distance from each other along an axis that is perpendicular to the direction of radiation of ultrasonic pulses along the surface of the product, while the linear parts of the working areas of the exciting and receiving high-frequency inductors are oriented to each other at an angle of 1207-10", which is characterized by the fact that the exciting high-frequency the inductor is shifted relative to the recording high-frequency inductor in the direction of radiation of surface wave pulses by the amount A, which is determined by the expression: Ame, where A is the length of the surface wave that is excited in the material of the controlled product, mm.