Patent ID: 11913087
Assignee: JFE STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 2:
3. A method for producing a high-strength steel sheet of claim 1, the method comprising:
hot rolling a slab having the chemical composition according to claim 1 with a hot-rolling finish temperature of 800° C. or higher and 950° C. or lower, a rolling reduction at a final stand of 8% or more, and a coiling temperature of 700° C. or lower to obtain a hot-rolled sheet;
cold rolling the hot-rolled sheet with a rolling reduction of 80% or more to obtain a cold-rolled sheet; and
subjecting the cold-rolled sheet to annealing whereby the cold-rolled sheet is heated at an average heating rate of 2° C/s or more and 35° C/s or less within a temperature range of 200° C. to a soaking temperature of 700° C. or higher and 850° C. or lower, held at the soaking temperature, and then cooled to a temperature range of 200° C. to 450° C. at an average cooling rate of 70° C/s or more to obtain an annealed sheet.