Influence of Low Temperature Heat Treatment on Iron Loss Behaviors of 6.5 wt% Grain-oriented Silicon Steels

In this study, the influence of low temperature heat treatment on iron loss behaviors has been investigated in 6.5 wt% grain-oriented silicon steels fabricated by a SiO2 textile method. Heat-treatment under hydrogen atmosphere was carried out for 1 hr in the temperature range of 500 to 800°C. As a result, the minimum iron loss was obtained in a sample annealed at 600°C. Transmission electron microscopy analysis showed that B2 and D03 antiphase domains existed in all heat-treated samples but D03 size was maximized after 600°C heat-treatment. In addition, magnetic domains cut through these antiphase boundaries. Therefore, the low iron loss of the sample annealed at 600°C should be ascribed to the reduction in the area of the antiphase boundaries which acted as pinning centers in the magnetic domain walls.