Hot-rolled steel sheet
View Patent ↗A hot-rolled steel sheet includes a specified chemical composition and includes a steel structure represented by an area ratio of ferrite being 5% to 50%, an area ratio of bainite composed of an aggregate of bainitic ferrite whose grain average misorientation is 0.4° to 3° being 50% to 90%, and a total area ratio of martensite, pearlite, and retained austenite being 5% or less.
1. A hot-rolled steel sheet comprising:
a chemical composition represented by, in mass %,
C: 0.02% to 0.15%,
Si: 0.01% to 2.0%,
Mn: 0.05% to 3.0%,
P: 0.1% or less,
S: 0.03% or less,
Al: 0.001% to 0.01%,
N: 0.02% or less,
O: 0.02% or less,
Ti: 0% to 0.2%,
Nb: 0% to 0.2%
Mo: 0% to 0.2%
V: 0% to 0.2%
Cr: 0% to 1.0%,
B: 0% to 0.01%,
Cu: 0% to 1.2%,
Ni: 0% to 0.6%,
Ca: 0% to 0.005%,
REM: 0% to 0.02%, and
the balance: Fe and an impurity; and
a steel structure represented by
an area ratio of ferrite: 5% to 50%,
an area ratio of bainite composed of an aggregate of bainitic ferrite whose grain average misorientation is 0.4° to 3°: 50% to 95%, and
a total area ratio of martensite, pearlite, and retained austenite: 5% or less.
2. The hot-rolled steel sheet according to claim 1 , wherein the chemical composition satisfies one or more selected from the group consisting of, in mass %,
Ti: 0.01% to 0.2%,
Nb: 0.01% to 0.2%,
Mo: 0.001% to 0.2%,
V: 0.01% to 0.2%,
Cr: 0.01% to 1.0%,
B: 0.0002% to 0.01%,
Cu: 0.02% to 1.2%, and
Ni: 0.01% to 0.6%.
3. The hot-rolled steel sheet according to claim 1 , wherein the chemical composition satisfies one or more selected from the group consisting of, in mass %,
Ca: 0.0005% to 0.005% and
REM: 0.0005% to 0.02%.
4. The hot-rolled steel sheet according to claim 2 , wherein the chemical composition satisfies one or more selected from the group consisting of, in mass %,
Ca: 0.0005% to 0.005% and
REM: 0.0005% to 0.02%.