SU1293624A1 - Method of non-destructive testing of cylindrical articles - Google Patents

Abstract

The invention relates to non-destructive testing methods and can be used to measure the radius and electrical conductivity of non-ferromagnetic cylindrical articles. The purpose of the invention is to expand the functionality by simultaneously measuring two parameters of a cylindrical product. Helmholtz coils create a uniform transverse magnetic field, install two identical measuring coils at the same distance Hd from the longitudinal axis of the Helmholtz coils (KG), place the test piece so that its axis coincides with the longitudinal axis of the KG, measure the phase difference Cf of the applied and initial EMF the measuring coil, the amplitude of the initial EMF EQ and the sum of the introduced EMF E of the measuring coils. Predefined dependencies X (c) and K f (cf), where is the normal factor, determine the values of the generalized parameter X and the normalized amplitude K, and, using the specified values, determine the radius P and the specific tric conductivity from the product. 3 il. Sl e

Description

112

The invention relates to non-destructive testing methods and can be used to determine the structural and geometric characteristics of cylindrical articles made from non-magnetic metals.

The purpose of the invention is to expand the functionality by measuring also the radius of the product.

FIG. 1 shows a diagram of an apparatus for implementing the method of FIG. 2 is a graph of the generalized parameter X as a function of the phase angle tf between the induced EMF E and the initial EMF equal to the secondary voltage of the secondary winding of the mutual inductance EJJ in FIG. 3 - graphical dependence of the amplitude of the normalized EMF K on the magnitude of the phase angle C |).

A device that implements the proposed method contains coils 1 Helm Holz. used to create a uniform transverse magnetic field, conducting a non-magnetic product 2, placed in such a way that its axis coincides with the longitudinal axis of the Helmholtz coils, and the magnetic field is directed perpendicular to it

axes, measuring coils 3 and 4, mounted on the same axis diametrically opposite to the sample, coils 5 and 6 of mutual inductances, generator 7, voltmeters 8 and 9, and phase meter 10. Measuring

thirty

--one (

R

Specific electrical value

the circuit is adjusted in such a way that the conductivities of item 2 are found.

in the absence of product 2 at the same current value in the Helmholtz coils 1 and in the primary windings j of the coils 5 and 6 of the mutual inductances of the EMF of the measuring coils 3 and 4 and the secondary windings of the coils 5 and 6 of the mutual inductances were the same.

Determination of the radius and electrical conductivity of a cylindrical article is carried out as follows.

The generator 7 sets the frequency of the exciting floor. A voltmeter 8 measures the emf E of the secondary winding of the mutual inductance coil 5, and the voltmeter 9 measures the emf of E, equal to the sum of the emf of two pairs of counter-connected measuring coils 3 and 4 and the secondary windings, coils 5 and 6 of mutual inductances. Phase meter 10 measures the phase angle between the EMF E and the EMF of one pair of counter-connected measuring coil 4 and the secondary winding of the coil 6 of mutual inductance. The magnitude of the measured angle q) from the graphical dependence (Fig. 2) determines the magnitude of the generalized parameter X. For the same value (from the graph (Fig. 3), determine the magnitude of the amplitude of the difference normalized

EMF K L-S-C-,

where is the form factor.

0 equal

one

2 (R / a)

R tnsh; p

(one)

0

five

where R is the radius of the product;

a - average measuring radius

coils;

X is the distance from the product axis to the middle of the measuring coils 3 and 4, equal to Xd X, / 2, where Xjj is the distance between the centers of the measuring coils 3 and 4.

Using expression (1), as well as measured and found values, determine the radius R of the cylindrical article 2

--12)

R

Specific electrical value

use of the expression for a generic parameter

X R4lxiofUh6o

In this case, the value of electrical conductivity of a nonmagnetic (fU 1) conductive cylindrical product 2 is determined at a given circular frequency of the exciting field from the expression

b

X2

(3)

where (U (j is the magnetic constant).

An example. The sample is made of copper alloy. Measured values: а 11.3-105 „Хд 22, m, 0 110 i, Cf 35.0 °, Е 0.1135 V, Е 0.0846 Century

From the graphical dependence (Fig. 2) for the measured we find X 3,05, and on the graph (Fig. 3) we determine that

K.

1,246. Using a CK 2

(2), we find the radius of the cylindrical product 2, equal to 95 m. Substituting this value of R into formula (3), we determine the specific electrical conductivity of product 2b 5.96-10 S / m. Measurement of the radius of the product with a micrometer was 18.99 “10 3 m, and the values of b, measured by the bridge method (accuracy class 0.2), were 6.04. Here, the measurement errors of R and b respectively are 0.2% and 1.3%.

Claims (1)

Invention Formula The method of non-destructive testing of cylindrical products, which consists in creating a uniform transverse magnetic field with the help of Helmholtz coils, sets the measuring coil at a fixed distance Xp from the longitudinal axis of the Helmholtz coils so that its plane is perpendicular to the direction of propagation of the magnetic field, the amplitude of the initial EMF Eg of the measuring coil is determined, the test piece is placed so that its axis coincides with the longitudinal axis of the Helmholtz coils, the difference t is measured f phases of insertion and initial EMF of the measuring coil and on The value of the generalized parameter X, which takes into account the specific electrical conductivity of the product, characterized in that, in order to expand the functionality by measuring also the radius of the product, at a distance of 2iXo from the first measuring coil and parallel to it different An identical second measuring coil is placed, the amplitude E of the sum of the inserted EMF of the measuring coils is measured, according to the previously constructed dependence of the normalized amplitude K on q, where is the form factor, the value K is determined that corresponds to the measured phase, and the radius R and specific electrical conductivity of the item determined from ratios. - o2 .Eg R „G, And mir .. 2-K.E, i - - rru7x ij 6 Xf P | UoCO where a CO f -the average radius of the measuring coils; -frequency magnetic field; - magnetic constant; X  RLGo Fmgl 18 3S S4 72 ea Thebes. 2