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摘要

This high-strength steel sheet includes: in terms of percent by mass, 0.03 to 0.10% of C; 0.01 to 1.5% of Si; 1.0 to 2.5% of Mn; 0.1 % or less of P; 0.02% or less of S; 0.01 to 1.2% of Al; 0.06 to 0.15% ofTi; and 0.01 % or less ofN; and contains as the balance, iron and inevitable impurities, wherein a tensile strength is in a range of 590 MPa or more, and a ratio between the tensile strength and a yield strength is in a range of 0.80 or more, a microstructure includes bainite at an area ratio of 40% or more and the balance being either one or both of ferrite and martensite, a density of Ti(C,N) precipitates having sizes of 10 nm or smaller is in a range of 10 10 precipitates/mm 3 or more, and a ratio (Hvs/Hvc) of a hardness (Hvs) at a depth of 10 µm from a surface to a hardness (Hvc) at a center of a sheet thickness is in a range of 0.85 or more.