| 摘要 |
PROBLEM TO BE SOLVED: To remove the phenomenon of unstability of magnetic properties incidental to the cold rolling of an Al-containing grain oriented silicon steel sheet at high draft and to obtain a grain oriented silicon steel sheet excellent in magnetic properties by precipitating fine carbides of specific grain size just before final cold rolling and performing final cold rolling by means of plural passes under specific conditions. SOLUTION: An Al-containing grain oriented silicon steel slab is hot-rolled and then cold-rolled once or cold-rolled two more times while process-annealed between cold rolling stages into final cold rolled sheet, followed by decarburizing annealing and final finish annealing. In this grain oriented silicon steel sheet manufacturing method, fine carbides of 20-2000Å average grain size are previously precipitated in the steel just before the final cold rolling stage in the cold rolling process. Then, this final cold rolling is carried out by means of plural passes at 30-75% draft at a temp. as low as <=140 deg.C in the first half, while performing two or more reduction passes at a temp. as high as 150-300 deg.C in the second half. Further, the total draft, as the sum of the draft in the first half and that in the second half, is regulated to 80-95%. |
