Abstract
Primary recrystallized Fe–3%Si specimens containing AI and nitrided were annealed
intermittently with the heating rate of 15℃/h in 100% N2 atmosphere. The magnetic
induction B8 was measured after each annealing. The onset of secondary recrystallization
was detected by the rapid rise of B8. The maximum B8 obtained was about 1.94 T when the
onset temperature of the secondary recrystallization was around 1075℃ regardless of the
initial grain size or nitrogen content.The same primary specimens were coated with MgO and annealed with the same heating
rate in 5% H2–N2. The maximum B8 obtained was nearly same as with the above annealing
condition, however, the initial grain size and nitrogen content was quite contrary in this
annealing. The difference in the optimum grain size and nitrogen content for obtaining the
highest B8 between both annealings was explained on the assumption that