Secondary recrystallization behaviors and the formation mechanism of strong Goss textures of oriented electrical steels

Abstract

During secondary recrystallization of oriented electrical steels, the dispersed inhibitors strongly hinder grain boundary migration. The existing secondary recrystallization theories, which mainly focus on the initial migration behavior of grain boundaries, not only fails to clarify the mechanism of secondary recrystallization, but also cannot explain the common phenomenon that smaller Goss grains can eventually engulf all other grains. This study confirms that the significant molar volume effect generated by the precipitation of inhibitors within the ferrite matrix strongly inhibits the coarsening of the central layer inhibitors in steel sheets at high temperatures, but there is still a chance for coarsening of the surface layer inhibitors. Therefore, the surface grains can grow before the growth of grains in the central layer. The highly enhanced elastic anisotropy of ferrite at high temperatures results in slow boundary migration of surface large-sized non-Goss grains towards Goss grains, while surface Goss grain boundaries can quickly migrate towards adjacent small-sized non-Goss grains, allowing Goss grains to gradually accumulate an absolute advantage in larger size, engulf all other grains, and ultimately form a strong Goss texture.