Materials Science Forum, Vol.408-4, 1305-1310, 2002
Abnormal texture of grain-oriented electrical steel under high cold rolling reduction
The effect of the final cold-rolling reduction on electrical steels with different inhibitors is investigated. In strong inhibition system, complete secondary recrystallization of Goss texture is obtained under the final cold-rolling reduction from 50% to 87%. The intensity of Goss texture enhances according to the increase of the cold rolling reduction. In weak inhibition system, secondary recrystallization fails to occur under the final cold-rolling reduction over 70%, instead, abnormal texture with a wide grain-size distribution appears. Approximately, grain size ranges from 0.03mm to 10mm. The orientation of the abnormal texture is investigated using EBSP. Coarse grains over 1mm have [12, 4, 1)<148>, {100}<001> or Goss orientations. Fine grains under 0.10mmhave {411}<148>or {111} <112> orientations. We previously proposed the mechanism of the secondary recrystallization stressing the role of high-energy boundary with a misorientation angle between 20 and 45 degree. Goss orientation has the highest frequency of high-energy boundary in the primary recrystallized texture. High-energy boundary has a high mobility under the presence of inhibitors. In case of weak inhibition system, primary recrystallized grain has a coarse grain size. The driving force for the secondary recrystallization is small, and the selectivity of the mobile boundary considered to be reduced. In such a case, grains other than Goss grain can grow. Coarse grains over 1mm have considerably high value of the high-energy boundary around them, thus enhanced growth is caused by the high mobility of the high-energy boundary. The orientation of the fine grains under 0.10 mm is a main component of primary recrystallized texture. Fine grain is considered to grow by the size effect.