High strength steel sheet

A high strength steel sheet comprising, as a chemical composition, by mass %:

• C:
• 0.030% to 0.280%;
• Si:
• 0.50% to 2.50%;
• Mn:
• 1.00% to 4.00%;
• sol. Al:
• 0.001% to 2.000%;
• P:
• 0.100% or less;
• S:
• 0.0200% or less;
• N:
• 0.01000% or less;
• O:
• 0.0100% or less;
• B:
• 0% to 0.010%;
• Ti:
• 0% to 0.20%;
• Nb:
• 0% to 0.20%;
• V:
• 0% to 1.000%;
• Cr:
• 0% to 1.000%;
• Mo:
• 0% to 1.000%;
• Cu:
• 0% to 1.000%;
• Co:
• 0% to 1.000%;
• W:
• 0% to 1.000%;
• Ni:
• 0% to 1.000%;
• Ca:
• 0% to 0.0100%;
• Mg:
• 0% to 0.0100%;
• REM:
• 0% to 0.0100%;
• Zr:
• 0% to 0.0100%;
• and
• a remainder including Fe and impurities,
• wherein a metallographic structure includes, by an area ratio,
• ferrite:
• 20% to 70%,
• residual austenite:
• 5% to 40%,
• fresh martensite:
• 0% to 30%,
• tempered martensite and bainite:
• 20% to 75% in total, and
• pearlite and cementite:
• 0% to 10% in total,
• in a range of a ⅛ thickness to a ⅜ thickness from a surface, a number proportion of residual austenite having an aspect ratio of 2.0 or more with respect to the number of all residual austenite is 50% or more,
• at a sheet thickness ¼ position of a cross section parallel to a rolling direction and perpendicular to the surface, a standard deviation of area ratios of ferrite measured at 10 points every 50 mm along a width direction is less than 10%, and
• a tensile strength is 780 MPa or more.