SU1287067A1 - Method of contactless measuring of parameters of cylindrical conductive articles - Google Patents

Abstract

The invention relates to the field of non-destructive testing of metals and products. The goal is to expand the functionality of the method of contactless measurement of the parameters of cylindrical conductive products. In the description of the invention, a diagram of the device implementing the method is given. The goal is achieved by passing a current from a master oscillator 7 of a fixed frequency across the exciting conductor (VP) 1, a voltmeter 9 measures the electromotive force (EMF) of the first spatial harmonic (PP) on the measuring conductors 2.3, a voltmeter 10- EMF on the measuring conductors 4.5 second PG without sample 6. Then sample 6 is placed, current in VP 1 is kept constant, the EMF of the first and second PG is measured again, and the phase angle of the first PG is measured with a phase meter 11 relative to the reference phase of the signal from the mutual inductance coil 8, defined The values of the normalized amplitudes of both NGs are found, the ratio of the normalized amplitudes of the second NG to the square of the first is found, the relative magnetic permeability of sample 6 is determined, and the product’s radius is determined by the value of the EMF of the first NG, followed by determination of the specific electrical conductivity. 6 Il. F

Description

the position of the exciting and measuring conductors with respect to the sample under study; Fig. 2 shows the distribution of the spatial harmonics of the electromagnetic field around the circumference, og: which delimits one of the cross sections of the sample (2 const), as well as the location of the excitation (VP) and measuring (PI) conductors; FIG. 3 is a schematic diagram of a device implementing this method; FIGI, 4 - graphs of functional dependences of the ratio of the normalized amplitude of the second spatial harmonic Aj to the square of the normalized amplitude of the first spatial harmonic A, on the tangent of the phase angle of the first spatial harmonic tg f for different values of magnetic permeability | U; FIG. 3 shows the graphs of the dependences tg, on the generalized parameter x for fixed values of fU; figure 6 - graphs of the specific normal amplitude of the first spatial harmonic between the measuring windings of the PI and PI, and the secondary winding of KB 8.

The determination of the electromagnetic and geometrical parameters of the product under investigation is carried out as follows.

The alternating current passes from the master oscillator 7 of a fixed frequency through the exciting conductor VP 1, the first voltmeter 9 measures the EMF of the first spatial harmonic on the measuring conductors 2 and 3, and the second voltmeter 10 - the EMF on the measuring conductors 4 and 5 of the second spatial harmonic of the converter without sample 6 Then, the sample under study 6 is placed in the converter along the Z axis, while the current in VP 1 is kept constant. Measure the first voltmeter of the first spatial harmonic with the first voltmeter and the second voltmeter with the second voltmeter of the second spatial harmonic transformer.

. first spatial harmonics, 35 watches with sample 6, as well as a phase meter including the form factor / a / d (where d is the PI distance from the product axis, and is the product radius) from the generalized parameter x at various values (U. 40

The primary transducer contains (Fig. 1), a cusping pole (VP) 1 (one or more conductors), measuring conductors 2 and 3 for measuring the total emf of the first and second 45 spatial harmonics (PI, PI I) located on beams with Y О к Y 7, and measuring conductors 4 and 5 for measuring the EMF of the second

and

rum 11 is the phase angle of the first spatial harmonic with respect to the reference phase of the signal with KB 8. From the measured emf of the converter, the values of the normalized amplitudes of the first and second spatial harmonics, i.e.

A. E, / E

ten

BUT,

2

(one).

(2)

where E, „, E,

spatial harmony (PI

PI) j located on lucha.h with angle / - v

MI azimuth Y t -7 - from the VP, as well as sample 6.

The schematic diagram of the device (FIGURE 3) contains the master oscillator (SG) 7s of the mutual inductance coil (KB) 85, the primary side of which is connected in series with

50

55

- EMF converter without sample; E ,, E - EMF converter with a sample. Next, find the ratio of the normalized amplitude of the second harmonic to the square of the first. Then according to the graphs (Fig. 4) for the calculated value and the measured value tg Φ | The relative magnetic permeability of the sample, ju, is determined, after which, using the curve of the graph of Fig. 5, corresponding to the found value jti, -, the generalized parameter X is determined for the value of tg P,. For naira 11, the phase angle of the first spatial harmonic with respect to the reference phase of the signal with KB 8. From the measured emf of the converter, the values of the normalized amplitudes of the first and second spatial harmonics, i.e.

 HER

ten

2

(one).

(2)

where E, „, E,

- EMF converter without sample; E ,, E - EMF converter with a sample. Next, find the ratio of the normalized amplitude of the second harmonic to the square of the first. Then according to the graphs (Fig. 4) for the calculated value and the measured value tg Φ | The relative magnetic permeability of the sample, ju, is determined, after which, using the curve of the graph of Fig. 5, corresponding to the found value jti, -, the generalized parameter X is determined for the value of tg P,. For nai-zg / g

Thebes. 2

V e & J (j

97i / e.4

l / 2fffff

0, fy

5.1

Oj

Compiled by M. Bukharov Editor I. Segl nick Tehred L. Serdakova Proofreader A.T.

Order 7712/48 Circulation 730 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035 ,. Moscow, Zh-35, Raushsk nab. 4/5

U9.-S

Claims (1)

Invention Formula A method of contactless measurement of the parameters of cylindrical conductive products, based on the excitation in a sample of eddy currents with a variable magnetic field of a fixed frequency and measuring the amplitude and phase of the secondary voltage of the secondary winding of the converter, (with the aim of expanding the functional five 0 five 0 Owing to the possibility of simultaneously measuring three parameters of the product, along the generator of the cylinder, the exciting one is passed through a conductor located above the surface of the product and the EMF values of the first and second harmonic magnetic fluxes of the magnetic currents of the exciting current are measured without the test product the same harmonics of the spatial magnetic fluxes of the exciting and eddy currents in the product, and also measure the phase of the first harmonic emf on conductors located along the generator of the cylinder above its surface in places of the maxima of the spatial harmonics of the exciting current, i.e. on the rays Y 1 Y- / p, where Y is the angular coordinate in the cylindrical system, measured from the conductor with the exciting current; p.- harmonic number, moreover, the magnitude of the EMF of the first harmonic and its phases, as well as the EMF of the second spatial harmonic determine the magnetic permeability, the radius of the product is determined by the value of the EMF of the first spatial harmonic, followed by the determination of the specific electrical conductivity. - zg / g l / 2fffff Thebes. 2 V e & J (j 97i / e.4 0, fy 5.1 Oj Compiled by M. Bukharov Editor I. Segl nick Tehred L. Serdakova Proofreader A.T. Order 7712/48 Circulation 730 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035 ,. Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, Projecto St., .4 U9.-S