SU1305531A1 - Method for eddy-current testing of cylindrical articles - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to control the quality of electrically conductive cylindrical products. The purpose of the invention is to increase the reliability of control by determining the heterogeneity of the electrophysical properties in the surface layer of the test article is achieved by measuring the second balance frequency; Two reference voltages are selected with phases corresponding to the phases of the applied voltages in the interaction of the eddy current transducer with a homogeneous object in two different modes characterized by generalized parameters x R, -Jco (5 (U and, determine the frequency of CO, and cOj phase balance for the selected reference voltages and the difference cOj / co, - K determine the result of the control i (f)

Description

The invention relates to non-destructive testing and can be used to control the quality of cylindrical electrically conductive products.

The purpose of the invention is to increase the reliability of control by determining the heterogeneity of the electrophysical properties in the surface layer of the test item.

The method is carried out as follows.

Based on the thickness of the surface layer being monitored, the value of the generalized parameter x R is chosen (5 (u, where R, is the product radius; (l) is the circular frequency of the supply current; G and ru is the specific conductivity and magnetic permeability of the product material, respectively. The second value is selected from the condition of 1.5 gKb10, based on the requirement of maintaining sensitivity to variation of the Controlled Parameter.

Then, using the well-known formula

r-2lWjjI ((gi) L argUsH-, - S JxTlJx) -

where,,) Modified Bessel functions of the first stroke of zero and first order, respectively, Ug. - the voltage applied to the eddy current transducer, the phases of the reference voltages are determined

wed, argU8H, and l / argUBH.

Here, UgH is determined for

x:

x

. ,, and UgH2 dl. The balance frequencies are then determined.

and CO

corresponding phases Cf, and cf. For this, a reference voltage is established with the phase 40 cf, and the frequency of the CO is changed until the phase Ug coincides with the phase of the reference voltage. If there is a match, the frequency of the balance is recorded (o -W,.) The OE balance frequency corresponding to the generalized parameter Xj is determined similarly.

If the product is homogeneous, then the time (Oi n is r, - -.

I

five

W,

As the non-uniformity of the surface layer of the product increases, this difference increases and is a measure of the non-uniformity of the surface layer.

Claims (1)

Invention Formula 5 A method of eddy current testing of cylindrical products, which consists in driving in a controlled product using a flow eddy current converter vortex. 0 currents, establish the phase of the reference voltage, regulate the frequency of the excited currents until the phase of the inverter is applied to the reference voltage and the balance frequency, characterized in that, in order to increase the reliability of control by determining the heterogeneity of the electrophysical properties in the surface layer of the product under test, select two reference voltages with phases corresponding to the phases of the applied stresses for the two values of the generalized parameters x, R, .x, where R, is radium 5 products; сО is the circular frequency of the excited currents; G and ш are the specific conductivity and magnetic permeability of the material of the product, respectively; but; K is the coefficient of proportionality, the CO and CO j balance frequencies are determined for the selected reference voltages, and the result of the control is determined from the difference Qj / SC, K.