A new technique to obtain an equivalent indirect hysteresis loop from the distortion of the voltage measured in the excitation coil

A new technique to calculate an equivalent indirect hysteresis loop, $B_{\mathrm{ ec}}$ – $H$ loop, from the distortion of the voltage measured in the magnetic excitation coil is proposed. The aim is to facilitate the industrial implementation of magnetic characterization reducing hardware and error sources of the measuring system, as pick-up coils and their conditioning stages are not necessary. With the $B_{\mathrm{ ec}}$ – $H$ technique, the characterization of two sets of materials with very different properties using a simplified electromagnetic system has been achieved. Specifically, the change in the microstructure of annealed low-carbon steel samples was monitored and the hardness of ultrahigh steel sheets was characterized. Moreover, the conventional hysteresis cycles and $B_{\mathrm{ ec}}$ – $H$ loops are compared, and the obtained lineal relationships between the parameters derived from conventional hysteresis and $B_{\mathrm{ ec}}$ – $H$ loops verify that the $B_{\mathrm{ ec}}$ – $H$ loops can provide equivalent parameters for magnetic characterization of steel samples as conventional hysteresis loops.