A study of local microstructure and texture heterogeneities in a CGO Fe3%Si alloy from hot rolling to primary recrystallization

The Goss texture developed after secondary recrystallization in Conventional Grain Oriented (C.G.O.) silicon steels allows minimization of power losses in transformer cores. The mechanisms of formation and evolution of Goss grains from the hot rolling stage up to the primary recrystallized state are not still well clarified. This work deals with characterization of the local microstructure and texture heterogeneities by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Electron Back Scattered Diffraction (EBSD). A detailed study of the microstructure shows that grains form a band structure decorated by thin carbides strings or lamellae found through the sheet thickness. The main texture components determined by XRD are the a and y fibers, the {001} <u v w> and the Goss orientations. A large variation in their volume fraction is observed at different sheet thickness in the sample and at different stages of the thermomechanical process. It is worthy to note that the Goss grains lying at the quarter of the sheet thickness are present either as bands parallel to the rolling direction at the early stage of processing route (hot rolled state) or within the {111} <112> grains for the subsequent steps.