Local identification of magnetic hysteresis properties near cutting edges of electrical steel sheets

Technological processes performed on electrical steel influence drastically their magnetic properties. The local mechanical state, changed by the introduction of cutting stresses and strains, degrades the local magnetic properties of the material. Therefore, the need exists to characterize accurately the change of the magnetic properties as a function of the distance from the cutting edge. We present a nondestructive experimental setup where spatial and time-dependent voltages are measured on the basis of needle probe sensors. We simulate the needle potentials, using a forward numerical model, starting from spatial dependent material properties, characterized by the Preisach model. Finally, we introduce a suitable algorithm which solves the inverse problem in order to recover the local magnetic properties starting from the measured potentials.