An EBSD investigation on the columnar grain growth in non-oriented electrical steels assisted by strain induced boundary migration

摘要

Recent studies regarding the development of high efficiency grain non-oriented (GNO) electrical steels demonstrate that development of columnar-grained microstructures prior to cold rolling is an efficient method to improve the magnetic behavior of the final product. However, the columnar morphology obtained by annealing of the hot-rolled bands was not developed after further processing by cold rolling and final annealing. Understanding the effects of plastic deformation on the development of such microstructures will help to promote them during the final annealing and improve even more the magnetic behavior of these materials. The present research reports the effects of small plastic deformations (0-25%) and annealing time (10-180 min) on the development of columnar microstructures in GNO electrical steels. The columnar grain growth is explained in terms of the strain induced grain boundary migration (SIBM) mechanism, based on the changes in the grain average misorientation (GAM) maps obtained by electron backscattering diffraction (EBSD). (C) 2019 Elsevier B.V. All rights reserved.