Steel sheet and manufacturing method thereof

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

• C:
• 0.030% to 0.180%;
• Si:
• 0.030% to 1.400%;
• Mn:
• 1.60% to 3.00%;
• Al:
• 0.010% to 0.700%;
• P:
• 0.0800% or less;
• S:
• 0.0100% or less;
• N:
• 0.0050% or less;
• Ti:
• 0.020% to 0.180%;
• Nb:
• 0.010% to 0.050%;
• Mo:
• 0% to 0.600%;
• V:
• 0% to 0.300%;
• a total of Ti, Nb, Mo, and V:
• 0.100% to 1.130%;
• B:
• 0% to 0.0030%;
• Cr:
• 0% to 0.500%;
• and
• a remainder of Fe and impurities,
• in which a microstructure includes, in terms of area ratio,
• bainite:
• 80.0% or more,
• a total of fresh martensite and tempered martensite:
• 20.0% or less, and
• a total of pearlite, ferrite, and austenite:
• 20.0% or less,
• in a crystal orientation distribution function of a texture at a sheet thickness ¼ position,
• A/B that is a ratio of a maximum value A of pole densities at Φ=20° to 60° and φ1=30° to 90° in a cross section of φ2=45° to a maximum value B of pole densities at Φ=120° to 60° and φ1=30° to 90° in the cross section of φ2=45° is 1.50 or less,
• a total of the maximum value A and the maximum value B is 6.00 or less, and
• a tensile strength is 1030 MPa or more.