Abstract: The effects of oxidizing atmosphere on the electromagnetic properties, microstructure and surface state of Fe2 %Si nonoriented electrical steel during annealing were investigated by using multi atmosphere continuous annealing furnace. The results showed that, when the oxygen content in the furnace increased from 3×10-6 to 52×10-6, the hysteresis loss in the iron loss P1.5/50 increased from 1.78 W/kg to 2.14 W/kg, the eddy current loss remained basically unchanged, the anisotropy of iron loss increased from 9.3 % to 11.5 %, and the magnetic induction B50 decreased from 1.731 T to 1.727 T. During annealing, the oxidizing atmosphere in the furnace caused the generating of oxide layer and inner nitriding layer on the surface of electrical steel, and the increasing internal stress in the steel, which led to the increase of hysteresis loss.

Key words: oxidizability, atmosphere, nonoriented electrical steel, hysteresis loss, magnetic induction