Evolution of Goss orientation during thermal heating with different heating rate for primary recrystallization in grainoriented electrical steel

Abstract

In order to understand how exact Goss-oriented grains form in electrical steel, we studied Goss orientation and microstructure during primary recrystallization using electron back-scattered diffraction. In particular, we examined the effect of heating rate (20°C/s and 150°C/s) on the primary recrystallization behavior. In a cold rolled sheet, the Goss fraction in the outer layer is more than twice that in the inside layer, particularly because the fraction of Goss±5° grains is much greater at the surface compared with the inner part. When primary recrystallization is completed, the fraction of grains that have Goss±5° and ±10° orientations in the outer and inner layer appear to be similar regardless of the heating rate, and the fraction of Goss±15° grains appears to be higher when the sheet is subjected to a rapid heating rate than when it is subjected to a typical heating rate. In addition, the number of Goss±5° grains corresponding to a rapid heating rate is twice that corresponding to a typical heating rate, with smaller grain sizes and a more uniform distribution. © 2013 ISIJ.