Study on the recrystallization microstructure and texture evolution of a rolled 0.075 mm ultra-thin grain-oriented silicon steel

Abstract

Abstract This paper investigated the recrystallization behavior of a rolled 0.075 mm ultra-thin grain-oriented silicon steel, and microstructure and texture evolutions were studied. At the early stage, dominant {hk0}<001> recrystallized grains were ascribed to the preferential {hk0}<001> nucleation, then their growth was reduced by texture pinning effect. In contrast, a few ‘random’ grains grew excessively to consume surrounding {hk0}<001> fine-grained matrix, meanwhile nuclei originating from initial non-Goss grains also showed size advantage and further grew. Despite of quasi-two-dimensional microstructure of ultra-thin sheet, the anisotropic surface energy did not show marked effect on grain growth difference. Those coarse grains, which were 10 times larger than the matrix grains, were surrounded by high energy (HE) boundaries, indicating that their growth was driven by high grain boundary mobility. With the increasing annealing time, the formation of {hk0}<001> oriented assemblies and the growth of non-{hk0}<001> oriented grains contributed to the overall grain size increase. Regarding the relationship between microstructure, texture and magnetic properties, {hk0}<001> texture was weakened and reduced magnetic induction accordingly, and the combination of growing while heterogeneous grain size and changing texture made iron loss a first decrease and then increase tendency. It is essential to control annealing time to obtain suitable combination of microstructure and texture.