Magnetostriction, Barkhausen noise and magnetization processes in E110 grade non-oriented electrical steels

Magnetostriction and Barkhausen noise are investigated in non-oriented electrical steels, with composition FeSi3.2%, corresponding to the E110 grade produced by ACESITA (Brazil), as a function of both, the magnetic induction level and the angle between the applied magnetic field and the rolling direction. The aim of this study is to understand the magnetization and hysteresis loss processes for this steel, identifying the magnetization mechanism taking place when magnetic field is applied in directions not aligned with the rolling direction, mainly at high magnetic induction levels (above 0.8 T). It is shown that the Barkhausen noise is always present at these high induction levels which can be associated to domain wall motion and to the nucleation and annihilation of 180° and 90° domains as well as to their evolution with the applied field. Thus, it is shown that the origin of the high induction loss in these samples is the motion of domain walls, irrespective to the angle with respect to the rolling direction.