Inductography

Inductography - (inducto- + Greek grapho write, depict) a non-destructive testing method based on recording changes in the magnetic flux in a controlled product as it moves through the inductance coil of the sensor or vice versa.

It is used to identify surface and subsurface defects in products made of ferromagnetic materials. Allows you to detect various defects: cracks, delaminations, pores, inclusions, etc.

It is based on the fact that defects in the material disrupt the uniformity of the magnetic field in it and cause the appearance of scattered magnetic flux. By recording changes in magnetic flux, the presence and location of defects can be determined.

Inductography is used in the inspection of cast parts, welds, pipes, rails, wire and other products and materials.

Inductographic recording is an electrical recording of a magnetic field formed when an electromagnetic oscillation is excited in an inductor by an alternating electric current.

This method of recording a magnetic field on a plane consists of measuring the horizontal component of the magnetic field induction by moving eddy currents (Faraday effect). It is used mainly to study the magnetic properties of matter in a changing magnetic field. With the help of I.G., the magnetic characteristics of ferromagnets are recorded (for example, the magnetization curves of M.-T. Odenburg), spin-polarized materials (Stern-Gerlach curves), etc. In modern I.G. equipment, usually used in laboratories, it is recorded not the horizontal component of the induction field of moving eddy currents, but the vertical component of the induction of an alternating magnetic field.

Induction graphic recording devices with a maximum recording frequency of about 3 ms allow a time resolution of 2-3 minutes. This makes it possible to record the fronts of magnetic moment pulses that arise, for example, in a thin nuclear beam as it passes through the sample. However, human “perception” of the rate of change of magnetic flux up to 0.1-1% c is inaccessible to human perception; the complete inertia of the induction graphing apparatus contradicts the very essence of the method.

Interest in the method is gradually fading away, giving way to nuclear optical methods. Their area of ​​application is the study of the magnetic properties of condensed matter, atomic nuclei, and