| 主权项 |
1. A production method for a grain-oriented electrical steel sheet, the method comprising:
subjecting a steel slab to hot rolling, without re-heating or after re-heating, to obtain a hot rolled sheet, the steel slab having a composition consisting of, by mass % or mass ppm, C: 0.08% or less, Si: 2.0% to 4.5%, Mn: 0.5% or less, S: less than 50 ppm, Se: less than 50 ppm, O: less than 50 ppm, sol.Al: less than 100 ppm, N controlled within a range satisfying the relation of sol.Al/(26.98/14.00) ppm≦N≦80 ppm, and the balance being Fe and incidental impurities; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet of final sheet thickness; then subjecting the cold rolled sheet to nitriding treatment with a nitrogen increase of 50 ppm or more and 1000 ppm or less, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and setting the staying time in a temperature range of 300° C. to 800° C. in the heating stage of secondary recrystallization annealing to 5 hours or more to 150 hours or less. |
