Hot-rolled steel sheet

A hot-rolled steel sheet having a chemical composition containing, in mass %,

• C:
• 0.100 to 0.350%,
• Si:
• 0.01 to 3.00%,
• Mn:
• 1.00 to 4.00%,
• sol. Al:
• 0.001 to 2.000%,
• Si+sol. Al:
• 1.00% or more,
• Ti:
• 0.010 to 0.380%,
• P:
• 0.100% or less,
• S:
• 0.0300% or less,
• N:
• 0.1000% or less,
• O:
• 0.0100% or less,
• Nb:
• 0 to 0.100%,
• V:
• 0 to 0.500%,
• Cu:
• 0 to 2.00%,
• Cr:
• 0 to 2.00%,
• Mo:
• 0 to 1.00%,
• Ni:
• 0 to 2.00%,
• B:
• 0 to 0.0100%,
• Ca:
• 0 to 0.0200%,
• Mg:
• 0 to 0.0200%,
• REM:
• 0 to 0.1000%,
• Bi:
• 0 to 0.020%,
• one or more of Zr, Co, Zn and W:
• 0 to 1.00% in total, and
• Sn:
• 0 to 0.050%,
• in which Tief represented by the following Formula (a) is 0.010 to 0.300%, and
• the remainder comprising Fe and impurities, and
• a microstructure comprising, in area %,
• ferrite:
• 10 to 30%,
• bainite:
• 40 to 78%,
• retained austenite:
• 12 to 30%,
• fresh martensite:
• 5% or less, and
• pearlite:
• 5% or less,
• wherein the ferrite has an average particle size of 5.00 μm or less,
• wherein a difference between an average nanoindentation hardness of the ferrite and an average nanoindentation hardness of the bainite is 1,000 MPa or less, and
• wherein the tensile strength is 980 MPa or more:
• Tief=Ti−48/14×N−48/32×S (a)
• where each element symbol in Formula (a) indicates their content (mass %).