Effects of processing conditions on the final microstructure and magnetic properties in non-oriented electrical steels

This paper reports the effects of tensile deformation and annealing conditions on the microstructure and magnetic properties of non-oriented electrical steel. The samples were subjected to tensile strains between 8% and 25% and subsequently annealed in air at temperatures from 700 to 900 degrees C. The experimental results show that the crystallographic texture of annealed samples depends strongly on the annealing temperature. Fibers textures of type (011)//RD, (001)//ND and (111)//ND, are obtained at temperatures below the Ae(1). In contrast, annealing at temperatures within the two-phase field region (Ae(1) < T < Ae(3)) promotes the development of [332][(1) over bar (1) over bar3] and [110][001] textures components. These results are supported by calculations with JMatPro software which show that the Ae(1) and Ae(3) transformation temperatures are 725 and 930 degrees C, respectively. It was also found that the final recrystallized grain size is inversely proportional to the deformation level imposed before the annealing it means, samples with higher deformation result in smaller grain size. In addition, energy losses in annealed samples are higher for higher levels of deformation, which indicates that grain size is the main micro structural parameter that affects the magnetic behavior of annealed samples. (C) 2016 Elsevier B.V. All rights reserved.