| To investigate the effects of the cooling rates of hot bands on the magnetic induction of AIN-based high permeability grain-oriented silicon steels, specimens prepared by vacuum induction melting were hot-rolled to 2.3㎜ in thickness and subsequently cooled with various rates. The cooling rates of hot bands used in this study were 120℃/sec(water quenching), 50℃/sec(oil quenching)and 10℃/sec(air quenching).The dependency of the magnetic induction on the cooling rate was examined in terms of such metallurgical factors as distribution of AIN ppt., microstructures and textures in the hot hands and the decarburized sheets. When the cooling rate was 50℃/sec, the magnetic induction was found to be superior to those obtained at the specimens of the lower and higher cooling rates. In case of the lower cooling rate(10℃/sec), large number of agglomerated AIN precipitates were distributed, resulting in poor magnetic induction. In spite of uniform and fine AIN distribution in the specimens of the higher cooling rate(120℃/sec), more improved magnetic induction was not achieved. The main reason for the deterioration of magnetic induction at the higher cooling rate specimens was thought to be the increase unfavorable texture components in the primary recrystallized sheet., such as (100)〔110〕 and (112)〔110〕. |
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