Influence of Subsurface Layers on Goss-TextureDevelopment in Secondary Recrystallization of RGO Electrical Steel Sheet

Abstract

Regular grain oriented (RGO) electrical steel sheet used for power transformer cores is produced by a two stage cold rolling process with intermediate annealing and a subsequent decarburizing primary recrystallization. Its beneficial magnetic properties originate from a sharp Goss-texture developed by the following secondary recrystallization. By controlled thinning of the material the sharpness of this Goss-texture will be shown to strongly depend on texture and structure of the subsurface layers of the sheet. A less intense secondary recrystallization with deteriorated Goss-texture sharpness and magnetic properties was found if a critical surface layer was removed from both sides of the sheet at any processing step, but no such effect occurred after single-sided surface removal. This result led to a new interpretation of the model of "texture inheritance".