Distortion analysis of magnetic excitation – Inherent reflection of properties of ferromagnetic materials

Abstract This letter briefly presents an interesting set of results from a non-destructive magnetic measurement method named as the distortion analysis of magnetic excitation (DAME). The time derivative of the excitation voltage (VE) across the coil around the electromagnetic (EM) yoke plotted as a function of total applied voltage (VT) (named as the DAME profile) truly reflects the magnetisation behaviour of the ferromagnetic material introduced between the poles of the EM yoke to close the magnetic flux path. The shape of the DAME profile with a peak and trough clearly reflects the subtle changes in the composition, microstructure, grain orientation and stress through their effect on the magnetisation process in the ferromagnetic material placed between the poles of the EM yoke. This letter shows that the DAME profile measurement is a simple non-destructive evaluation (NDE) method to detect and determine variations in the properties of ferromagnetic materials and has tremendous potential for several applications related to the evaluation of ferromagnetic materials and components.