Evaluation of Microstructure and Magnetic Properties in Non-oriented Electrical Steel Strained by Tension

The effects of deformation on the microstructure and magnetic properties of non-oriented electrical steels were investigated. Box-annealed electrical steel sheets were deformed by tension at four different strains: 3%, 8%, 12% and 25%. The internal grain misorientation caused by tensile deformation was measured by electron backscattering diffraction (EBSD) with grain orientation spread (GOS) as an indicator of the lattice distortion. The experimental results showed that the average GOS value increases with the strain. The microstructure and crystallographic texture of deformed samples did not show a significant change in samples strained below 25%. However, the magnetic properties were strongly affected: coercivity was directly proportional to the square root of the GOS value and energy losses increased as the strain level was increased.