High-strength hot-rolled steel sheet and manufacturing method thereof

The present invention is to provide a high-strength hot-rolled steel sheet and a manufacturing method thereof having excellent stretch-flange formability and fatigue characteristics, by mass%, C: 0.020% than 0.060% or less, Si: 0. 40% or less, Mn: 0.50% than 1.20% or less, P: 0.030% or less, S: 0.030% or less, Al: 0.10% or less, N: 0.0100% or less, Ti : containing 0.050% to 0.110% or less, and the balance a composition consisting of Fe and unavoidable impurities, the area ratio of the ferrite phase is 95% or more, the amount of solute C in the steel 0.010 not less than%, carbides are finely precipitated containing Ti in the crystal grains of the ferrite phase, and the tissue average particle size of the carbide is less than 8 nm, further, the internal oxidation of the steel sheet surface layer portion 0.15 g / with m There, a high-strength hot-rolled steel sheet excellent in stretch flange formability and fatigue properties.