Patent ID: 11965222
Assignee: JFE STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  B  Y | IPC B  C

Claim 0:
1. A method for producing a hot-rolled steel sheet, the method comprising heating a steel slab having a composition containing, in terms of mass %,
C: 0.010% or more and 0.150% or less,
Si: 0.20% or less,
Mn: 1.00% or less,
P: 0.100% or less,
S: 0.0500% or less,
Al: 0.001% or more and 0.100% or less,
N: 0.0100% or less, and
the balance being Fe and unavoidable impurities, in which 0.002%≤[% P]+[% S]≤0.070% ([% M] denotes a content (mass %) of M element in steel) is satisfied;
rough-rolling the heated steel slab; in subsequent finish rolling, hot-rolling the rough-rolled steel slab under conditions of a finish-rolling inlet temperature of 1020° C. or higher and 1180° C. or lower, a rolling reduction in a final pass of the finish rolling of 5% or more and 15% or less, a rolling reduction in a pass before the final pass of 15% or more and 25% or less, and a finish-rolling delivery temperature of 800° C. or higher and 1000° C. or lower; after the hot rolling, cooling the hot-rolled sheet to a coiling temperature at an average cooling rate of 5° C./s or more and 90° C./s or less; and coiling the cooled sheet at a coiling temperature of 400° C. or higher and 800° C. or lower.