Effect of Nitrogen Content on Primary Recrystallization Behavior and Magnetic Property of Hi-B Steel

The effect of nitrogen content on primary recrystallization microstructure, texture and magnetic property of Hi-B steel was studied by means of optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). When nitrogen content increased gradually from 0.0055% to 0.0310%, the primary grain size and variation coefficient of nitrided sheet reduced from 26.85 μm, 0.590 to 18.87 μm, 0.525 - 0.565, respectively. Meanwhile, the primary recrystallization texture style of nitrided sheet was nearly identical to the texture style of decarburized sheet before nitriding treatment, but exhibiting a certain change on texture intensity. The variation of average magnetic induction value (B8) and core loss value (P17/50) were manifested to be M-shaped and W-shaped curves, respectively. When nitrogen content reached 0.0160%, the best value of the average magnetic property of the final product was obtained as follows: the B8 and P17/50 were 1.921 T and 0.968 W/kg, respectively. Meanwhile, the best performance, B8 and P17/50, of single sheet was 1.961 T and 0.854 W/kg.