Non-destructive testing of ferromagnetic materials using hand inductive sensor

TLDR: In this article, a hand inductive sensor is proposed for testing welded joints by measuring the magnetic resistance of the welding area, which is based on measuring the nonlinearity zone of the magnetization curve of the inductive element core material.

Abstract: Purpose: The need for reliability of industrial structures, machines and other equipment \nrequires more accurate testing of structural materials, especially ferromagnetic materials. \nTherefore, it is important to improve existing or develop new, more accurate methods and \ndevices for non-destructive testing.\nDesign/methodology/approach: Non-destructive testing of ferromagnetic materials \nis carried out by surveying a local magnetic field or determining the section magnetic \nresistance of a material using the proposed new type of sensor as the hand inductive \nelement on a toroidal core with additional magnetic cores.\nFindings: This sensor has a simple design and high response characteristic, which has \nbeen confirmed experimentally. Such a sensor can be used for testing welded joints by the \nproposed method, which is based on measuring the magnetic resistance of the welding \narea.\nResearch limitations/implications: Analytical physical processes research that \noccurred in the magnetic core material of the sensor coil core, used as a sensitive element, \nis complicated by the nonlinearity of the magnetization curve of the material of the core of \nthe sensitive element and the lack of a single analytical relationship to fully describe the \nmagnetization process of ferromagnetic materials of inductive elements. Therefore, each \ncopy of the sensor will be an individual graduation.\nPractical implications: The proposed version of the hand inductive sensor allows to \nperform non-destructive testing during the operation of ferromagnetic structures and \nwithout special requirements to external conditions with low costs and the possibility of \ncomputer processing of data.\nOriginality/value: The use of the nonlinearity zone of the magnetization curve of the \ninductive element core material made it possible to obtain a variant of a magnetic sensor \nthat is close in sensitivity to fluxgate and, at the same time, is much simpler in design using \nnon-deficient materials. The use of a ferrite core with low saturation induction requires a \nsmall circuit supply voltage, but a generator power reserve. The proposed hand inductive \nsensor is sensitive to the presence of extraneous ferromagnetic objects, and responds \nonly to a magnetic field. The high magnetic resistance of the inductive sensor allows it to be used on uneven and dirty surfaces. High sensitivity allows to detect small deviations of \nthe magnetic fields of dispersion of a welded joint with their comparison along the entire \njoint length. All of this gave new opportunities for more accurate non-destructive testing of \nstructural elements and materials.\n\n