Shozaburo Nakashima1, Kunihide Takashima1 and Jirou Harase1
1R & D Laboratories-III, Nippon Steel Corporation, Kitakyushu
A study has been made on the effect of the final thickness, 0.60-0.18 mm, under the same reduction rate in cold rolling on the secondary recrystallization of the grain-oriented electrical steel produced by the single-stage cold rolling process.
(1) On the heating period of final annealing in the case of the atmosphere of H2, 0.60 mm thick specimen undergoes perfect secondary recrystallization, but specimens thinner than 0.60 mm undergo imperfect secondary recrystallization. The thinner the specimen is, the more part of it is occupied by fine grains. This phenomenon is considered to be attributed to the decrease in MnS and AlN content, i.e., the decline of the effect of inhibition leads to the normal growth of matrix grains in the center part of the thickness on the heating period of final annealing in case of thin specimens.
(2) On the heating period of final annealing in the case of the atmosphere of the mixture of H2 and N2, all specimens undergo perfect secondary recrystallization. In this case, the thinner the specimen is, the lower the magnetic flux density becomes. This phenomenon is considered to be attributed to the increase in AlN content, i.e., the enrichment of inhibitors which is supposed to cause the increase of the deviation from Goss orientation in the secondary texture in case of thin specimens.
single-stage cold rolling process, electrical steel, grain-oriented electrical steel, secondary recrystallization, thickness
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