Effect of Cr on secondary recrystallization behaviors in high permeability grain oriented silicon steel manufactured by low-temperature slab reheating

The effect of Cr on secondary recrystallization behaviors of high permeability grain oriented silicon steel manufactured by low-temperature reheating was studied by transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and magnetic properties measurement. The results show that Cr containing silicon nitride (Cr, Si) N precipitates after nitriding with the size below 150 nm and regular shaped. Furthermore, primary grain size becomes smaller and more uniform; In the heating stage of purification annealing, precipitates turn into composite silicon nitride (Cr, Al, Si) N. Due to the number of inhibitors is larger and the size is smaller, the pinning effect is stronger. So the starting temperature of secondary recrystallization increases 20 K, the analysis of Zener factor is in agreement with experiment results. With the addition of 0.145 wt% Cr, final grains become smaller and the iron loss (P-17/50) could be significantly reduced by nearly 5.4%.