V. E. Shcherbinin

Magnetic field of a short rectangular slot-type flaw

Analytic expressions for the magnetic field of a short rectangular crack are obtained with an approximate model for the magnetic-flux flow near a flaw.

Possibilities for the selection of magnetic field transducers for nondestructive testing

Magnetic field transducers that vary in their suitability for use in contemporary magnetic nondestructive testing are considered. The experimental data on the resolution of some transducer types are presented.

Problems of Evaluation of the Flaw Parameters in the Magnetic Nondestructive Testing

The magnetic leakage fields are investigated experimentally on rectangular-slit aw models for various magnetizing fields H0. It is shown that in certain cases the aw parameters can be incorrectly classified as a result of coincidence of their leakage fields. This is associated with both the choice of the magnetizing fields H0 and the effect of the aw width on the dependence of the aw field on H0: for wide aws this dependence is close to a linear function, whereas for narrow aws the dependence tends to the magnetization curve of the sample.

On the measures that are necessary for providing the safe operation of pipeline transport with nondestructive testing facilities

The state of pipeline transport and the system for its provision with nondestructive testing facilities were analyzed. A number of measures that, in the authors’ opinion, must contribute to the operational safety and reliability of pipeline transport in Russia were proposed.

Analysis of stress-corrosion flaws in main gas pipelines based on the results of in-tube nondestructive testing

The need for monitoring based on the results of in-tube magnetic testing of main gas pipelines is substantiated in this study. An analysis that is performed using the data of in-tube diagnostics of pipelines is the most complete and reliable source of information about the state of a main gas pipeline at the moment of monitoring. In particular, the efficiency of pig flaw detectors is clearly seen from the results of 5-yr nondestructive testing; the experience of inspection of main gas pipelines according to certain parameters is generalized.

On the development of national standards for magnetic and eddy-current nondestructive inspection of steel pipes

Comparative analysis of the technical level of different nondestructive-testing methods (ultrasonic, magnetic, and eddy-current) used in the production of seamless and HFC welded pipes is performed. To increase the quality of pipes produced for operation under elevated pressure and to unify nondestructive-testing methods and facilities used, standards for magnetic and eddy-current inspection are developed in accordance with the stated foreign acceptance levels.

On the solution of the inverse problem of magnetostatic tomography

A possible approach to estimation of the volumetric distribution of the magnetization vector in magnetized articles is considered. Measured values of the magnetostatic field outside an article are used.

Comparison of results of measuring the magnetic field of a crack by flux-gate meters with calculated data obtained within a model of constant magnetic charge density

Results of measurements of the coordinate characteristic of the magnetic field and its maximum gradient for a surface crack rectangular in section are compared with analogous magnitudes calculated by a model of a constant magnetic charge density. The measurements were performed using fluxgate meters. The optimum agreement of data on the maximum gradient was obtained in finding the extreme of a function depending on the effective depth of the crack and height of the observation point. The obtained values of these parameters are weak functions of the crack size.

On complex permeability in eddy-current flaw detection

This paper critically considers attempts to prove the frequency dependences of the electrical conductivity and magnetic permeability of metals at frequencies lower than 1 MHz. Such attempts were made by certain authors when studying the operation of eddy-current transducers. It is shown that the complex character of the output voltage of an eddy-current transducer is determined by the vector summation of the magnetic fluxes of the primary magnetizing alternating field and the field of eddy currents, which are induced by the primary field, in a tested article. The frequency dependence of the results of this summation is quite sufficient for a physically correct description of the operation of an eddy-current transducer without involving a hypothesis on the frequency dependence of the physical constants of the material of the tested article.

Indication of magnetic fields with the use of galvanic currents in magnetic-powder nondestructive testing

A difference in the potentials in a nonuniform magnetic field is shown to occur across electrodes that are placed into a ferromagnetic suspension, which is used in magnetic-powder nondestructive testing (NDT). This phenomenon may be used for the detection of flaws in ferromagnetic products.