Steel sheet and method for producing same

A steel sheet having a chemical composition comprising, by mass %,

• C:
• 0.050 to 0.300%,
• Si:
• 0.01 to 2.00%,
• Mn:
• 0.10 to 4.00%,
• P:
• 0.0001 to 0.0200%,
• S:
• 0.0001 to 0.0200%,
• N:
• 0.0001 to 0.0200%,
• Al:
• 0.001 to 1.000%,
• Ti:
• 0.001 to 0.500%,
• B:
• 0.0007 to 0.0100%,
• Co:
• 0 to 0.50%,
• Ni:
• 0 to 1.00%,
• Mo:
• 0 to 1.00%,
• Cr:
• 0 to 2.000%,
• Nb:
• 0 to 0.500%,
• V:
• 0 to 0.500%,
• Cu:
• 0 to 0.500%,
• W:
• 0 to 0.100%,
• Ta:
• 0 to 0.100%,
• Sn:
• 0 to 0.050%,
• Sb:
• 0 to 0.050%,
• As:
• 0 to 0.050%,
• Mg:
• 0 to 0.0500%,
• Ca:
• 0 to 0.050%,
• Y:
• 0 to 0.050%,
• Zr:
• 0 to 0.050%,
• La:
• 0 to 0.050%,
• Ce:
• 0 to 0.050%, and
• a balance of Fe and impurities, wherein
• the steel sheet comprises, by area ratio,
• ferrite:
• 5.0 to 40.0%,
• total of martensite and tempered martensite:
• 10.0 to 60.0%,
• bainite:
• 5.0 to 40.0%, and
• retained austenite:
• 5.0 to 25.0%,
• when there are remaining structures, the remaining structures consist of 10.0% or less of pearlite,
• in a surface layer region down to a depth of 100 μm from the surface in the sheet thickness direction, (Fe, Mn)2 B precipitates having a circle equivalent diameter of 50 to 300 nm are present in a number density of 1/500 μm2 or more.