Al Abbasi J. Development of an electromagnetic method and a device for sorting metal plates

In the dissertation work is devoted to the theoretical aspects of distribution of an alternating electromagnetic field in a ferromagnetic plate. The expressions describing the behavior of the amplitude and phase of the magnetic flux in a flat metal plate, which are the basis for the development and implementation of electromagnetic methods and devices for non-contact monitoring of magnetic and electrical parameters of flat metal products were obtained. Namely, when solving the inverse problem, the use of a differential transformer electromagnetic transducer for sorting the material of flat metal products is proposed. It is shown that each value of a given maximum error corresponds to a certain working area of universal transformation functions in the vicinity of the selected point. The general problem of applying the resonant scheme for parametric electromagnetic surface mount transducers for sorting metal plates is formulated. Multi-resonant methods of electromagnetic testing and the device implementing it are developed, which allows to increase the sensitivity of the transducer to changes in the electromagnetic parameters of the tested ferromagnetic plates twice and in the first approximation, to exclude the effect of temperature and gap between the primary transducer and the surface of the tested flat product. The experiments, after processing the results showed that the histogram of the output voltage of the sensor clearly shows the difference between the characteristics of the rolls of one grade of steel from two manufacturers. The proposed automated device that implements a multi-resonant method of sorting metal plates with similar electromagnetic parameters, significantly reduce the effect of the gap between the transducer and the test product, also reduces the effect of ambient temperature on the accuracy of monitoring. To verify the reliability of the results obtained repeated measurements of the coercive force at separately selected control points for the same samples of metal plates were carried out.