| The effects of microstructure before high temperature annealing on secondary recrystallization in conventional grain-oriented electrical steels are investigated. Before high temperature annealing, the cold rolled specimens were annealed at 600 and 850℃ for 200s in 25%H₂+75%N₂, in order to make the recovered and recrystallized microstructure, respectively. For the observation of grain size and precipitates, specimens were extracted at 700, 800, 900, 950 and 1000℃ during the heating step of high temperature annealing. For the recrystallized specimen before high temperature annealing, secondary recrystallization was nearly completed at 950℃ during high temperature annealing. However, in case of the recovered specimen, secondary recrystallization was formed at a higher temperature than 950℃. After high temperature annealing, better magnetic properties were obtained in the recovered specimen than in the recrystallized specimen. |
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