To produce a hot rolled steel sheet for hydroforming which has a strength of ≥500 MPa and excellent hydroforming properties free from the occurrence of cracking even upon swelling by hydroforming.

A slab having a steel composition comprising >0.01 to 0.13% C, 0.005 to 1.0% Si, 0.1 to 3.0% Mn, ≤0.04% P, ≤0.03% S, 0.001 to 0.1% Al, 0.02 to 0.2% Ti, 0.002 to 0.1% Nb and ≤0.01% N, further satisfying -0.05<4(C+N)-(Ti+V+Nb/2+Mo/2)<0.2, and the balance Fe with inevitable impurities is subjected to thermomechanical treatment, so as to produce a hot rolled steel sheet for hydroforming in which the area fraction of a ferritic phase with the average grain size of 1.1 to 10 μm is ≥95%, tensile strength is ≥500 MPa, and further, tensile strength×uniaxial tensile elongation is 14,000 (MPa%).

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