The Influence of Annealing Temperature on the Magnetic Properties of Cryo-Rolled Non-Oriented Electrical Steel

Abstract

The paper is focused on a comparison of the magnetic properties of the non-oriented isotropic electrical steel containing 3.5% Si. The material was processed by conventional ambient temperature rolling and progressive rolling at the cryogenic conditions at liquid nitrogen. Deformations of the samples in both thermal conditions were in the interval εÎ<5;35>[%]. Subsequently, the samples were heat treated at temperatures TÎ<900;1100> [°C]. Measuring of the magnetic properties was carried out in an alternating magnetic field at frequencies f= 50; 100; 150 Hz. At a frequency of 50 Hz were achieved smallest magnetic losses and therefore further measurements were made at a given frequency. Followed measurements of the magnetic induction were conducted at different intensities of the magnetic field. EBSD analyses were performed to obtain the IPF maps on which the resulting structure was evaluated after processing of the material. The specific magnetic losses were compared to different processing methods. The best magnetic properties defined as by minimal values of core loses were reached after samples rolled at cryogenic temperature followed by subsequently annealed. Also, higher proportion of cubic texture was archived after rolling at cryogenic temperature with compared to samples processed at ambient temperature.