摘要 |
Provided is a hot-rolled steel sheet that: comprises a chemical compound containing, in mass%, 0.030-0.10% of C, 0.5-2.5% of Mn, 0.100-2.5% of Si + Al; comprises, by area ratio, 80% or more of ferrite, 3-15.0% of martensite, and less than 3.0% of pyrite; has a number density of 5.0 grains/10000 µm2 or less of martensite having an equivalent circular diameter of 3 µm or higher at a position that is at a depth of 1/4 of the sheet thickness of the steel sheet from the steel sheet surface; and comprises a microstructure that satisfies formula (1). Formula (1): R/DM 2 ≥ 1.00 (in formula (1), R represents an average martensite interval (µm) that is defined by formula (2), and DM represents the average martensite diameter (µm)). Formula (2): R = {12.5 × (π/6VM)0.5 - (2/3)0.5} × DM (in formula (2), VM represents the area ratio (%) of martensite and DM represents the average martensite diameter (µm)). |