Steel sheet and method of production of same

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

• C:
• 0.15 to 0.35%,
• Si:
• 0.01 to 2.00%,
• Mn:
• 0.10 to 4.00%,
• P:
• 0.0200% or less,
• S:
• 0.0200% or less,
• Al:
• 0.001 to 1.000%,
• N:
• 0.0200% or less,
• Ti:
• 0 to 0.500%,
• Co:
• 0 to 0.500%,
• Ni:
• 0 to 0.500%,
• Mo:
• 0 to 0.500%,
• Cr:
• 0 to 2.000%,
• O:
• 0 to 0.0100%,
• B:
• 0 to 0.0100%,
• Nb:
• 0 to 0.500%,
• V:
• 0 to 0.500%,
• Cu:
• 0 to 0.500%,
• W:
• 0 to 0.1000%,
• Ta:
• 0 to 0.1000%,
• Sn:
• 0 to 0.0500%,
• Sb:
• 0 to 0.0500%,
• As:
• 0 to 0.0500%,
• Mg:
• 0 to 0.0500%,
• Ca:
• 0 to 0.0500%,
• Y:
• 0 to 0.0500%,
• Zr:
• 0 to 0.0500%,
• La:
• 0 to 0.0500%,
• Ce:
• 0 to 0.0500% and
• a balance of Fe and impurities,
• having a microstructure comprised of, by area ratio,
• a total of martensite and tempered martensite:
• 90.0% or more,
• a total of ferrite, pearlite, and bainite:
• 0% or more and 10.0% or less, and
• retained austenite:
• 0% or more and 5.0% or less, and
• having on the sheet surface a plurality of step differences having height differences of more than 5.0 μm at intervals of 0.01 mm or more and 2.0 mm or less.