SU1361479A1 - Device for electromagnetic flaw detection - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to measure the depth and depth of subsurface continuity defects of ferromagnetic objects. P, spruce of the invention - the expansion of functionality. In the device, an alternating current source 19, made in the form of a oscillating frequency generator, supplies the alternating frequency current of the magnetization system 20 and 21. The voltage measurement unit 22, the normalizing converter 23, the comparator 24 and the setting unit 257 form, with an amplitude-controlled AC source 19, a closed automatic control system that ensures constant magnetic flux P through ac - control with variation magnetization. Extremes:.., The frequency meter 7, the control key 8 and the memory element 9 are designed to determine and store the value f of the frequency at which the signal of the ferrosound converter 2 is maximum. Comparator 13, attenuator 14, control key 11 and element 12; Memories are designed to determine and memorize the frequency value f, corresponding to the reduction of the flux-gate converter signal n times (2ini5). The two-channel recorder 10 determines, by the obtained values of f and f and the calibration characteristics, the depth of the defect and the depth of the defect, 2 hp. f-ly, 1 ill. c & oo

Description

1 13614792

The invention relates to a non-linear transducer 2, establishing control, and can usually be used on a magnetic neutral.

Calibrated to measure the depth and depth of the magnetization system 21, i.e. on

Bins of subsurface occurrence of equal distances with respect to the semifunctional continuity properties of the electromagnet of the electromagnet of the 21 magnetization objects. Therefore, the measurement purpose of the invention — the expansion — the tap 18 is also placed on an equal footing.

functionality due to the distance from the electromagnet poles,

measurement of the depth and depth of the Q included in the system 21 of the magnetization of subsurface defects.and interacting with the reference

The drawing shows a sample structure 15, made of

on the circuit of the device for the electromagnet the same material as the controllable

flaw detection. Object.

The device contains a successor-ig. The device operates as follows, connected to generator 1, ferro-fold.

probe converter 2, com-source 19 AC current writer 3, selective amplifier 4, is thawed by a current of a varying frequency system-amplitude detector 5 and extrematortem 20 and 21 of magnetization. Wherein

6, connected in series by an hour to 20, the measuring wheel 18 is induced

totomer 7, controllable key 8, a connection proportional to the GF, where

The control input with output f is the magnetization current frequency; f extremator 6, memory element 9 is the magnetic flux through the control zone,

The recorder 10, the second input of which voltage measuring unit 22, is normalized to the output of the frequency meter 7 through the transducer 25, 23

cut in series the second 24 and setter 25 form with up-

swarm control key 1I and a second amplitude source 19

ment 12 memory, comparator 13, co-alternating current closed system

input input with an amplitude-automatic control output, a detector free of charge 5, a second input that provides an unchanged frequency F with a variable attenuator 14 with an output of element 9 of a f. Magnetic flux scattered

memory and connected, output to up-- received under the influence of the defect

controlling input of the controlled key of the seam and interacting with the

11, the reference sample 15 with the performed-probe converter 2, have

perpendicular to the surface stress, proportional to the weight of the holes 16 and 17 and the size of the redistributed defect

the coil 18, wound the magnetic flux continuity f,. WITH

a conductor passing through these from the increase in frequency magnetic flux T

 versatility. Due to the skin effect, the redistribution of the power is furthermore that the device contains a 40 ° section of the controlled alternating current 19 AC, which is reduced in the lower layers and observed in the form of amplified control in the upper layers. With this granitude of the oscillating frequency generator, ca between the layer with the increased and decreased

identical systems 20 and 2 magnetized by magnetic fluxes as

Connected to the output of the source, the increase in f tends to the upper pike 19 of the alternating current and the full surface. Therefore, the value of H will be

for example, in the form of auxiliary, have a maximum at a certain frequency

electromagnets, successively the connections e g de f depend both on the depth

The single unit 22 measuring the pressure of the defect, as well as from the depth of its bleaching, is a normalizing transducer 23p. gani. Since within the zone

with a transfer coefficient, a reverse control of the distribution of f along a long-proportional frequency, and the comparability of the defect can be considered uniform,

torus 24 connected by the second input f does not depend on the length of the defect. The century control unit 25 and the output - to the control f are registered when the input of the source 19 is switched by a variable signal by a fluxgate

go current. Measuring coil 18 up to 2 max.

encompasses the cross-section of the U reference value with an extremizer 6,

sample in the control zone, i.e., a controlled key of 8 y: element 9 of the pavilion area located under the ferrozone m.

For separate determination of h and & Additional information is used: the frequency fj, at which the signal of the flux-gate converter 2 is a given number n times less than the maximum signal at the frequency f, the number n () is set using an attenuator 14, the input of which is U | from the output of memory element 9. The comparator 13 turns on the controllable key 11 at the moment when the magnitude of the signal tJ is, and is obtained

wherein the frequency f is fixed in the memory element 12. The obtained values of f and f are fed to the recorder 10. In the simplest version, h and 8 integrity defects are determined by nomographs. To automate measurements, the recorder 10 is recommended to be implemented as a microprocessor with dependencies between f, f and P, h and an interpolation program embedded in its memory.

The proposed device provides high accuracy. Measurements of the frequency registration, independent of variations in the sensitivity of the fluxgate transducer and the gain of the measuring channel. In addition, it allows separate recording of the depth and depth of subsurface continuity defects, regardless of their length and variations of control conditions.

Claims (3)

1. A device for electromagnetic flaw detection, containing a current source, a first magnetization system connected to it, a generator connected in series, a ferro probe converter, a compensator, a selective amplifier and an amplitude detector, a recorder and a measuring coil, distinguished by the fact that with the aim of expanding A, Kozoriz Compiled by A. Tychinin Tehred A. Kravchuk Proofreader L, Pilipe Nko Order 6220/45 Circulation 776 Subscription VNIIPI. USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production: printing-printing enterprise, Uzhgorod, st. Project, 4 61479 functionality by measuring the depth and depth of subsurface defects, it is equipped with a frequency meter connected in series, the input of which is connected to the output of the current source, the first control key, the first memory element, the attenuator and the comparator connected to the output of the amplitude detector, an extremer connected between the output of the amplitude detector and the control input of the first g of the equal key, connected in series by the second control key, the first input of which is connected to the output of the frequency meter, and the second input to the output of the first comparator, and the second memory element, the reference sample on which the measuring coil is located, the second magnetization system designed for magnetizing the reference sample, 25 are connected in series by a voltage measuring unit connected by an input to the measuring coil, a normalizing transducer and a second comparator and a setter 30 connected to the second input of the second comparator, the current source is made in the form of a oscillating frequency generator and connected by a control input to the output of the second comparator and the output to the input of the second magnetization system, and the recorder is dual-channel and is connected by inputs to the outputs of the memory elements. 35 2. An apparatus according to claim I, characterized in that two through holes are made in the reference sample, and the measuring coil is wound by a conductor passing through these holes. 3. The device according to PP. I and 2, that is, the fact that the recorder is executed in the form of a microprocessor with an indicator.