Hot rolled steel sheet and method for manufacturing the same

A method of manufacturing a hot rolled steel sheet comprising subjecting a semi-manufactured steel material to heating, hot rolling including rough rolling and finish rolling, cooling after the completion of finish rolling, and coiling, thereby producing a hot rolled steel sheet, wherein

• the semi-manufactured steel material has a chemical composition including, by mass%,
• C:
• 0.055% to 0.15%, Si:
• not more than 0.2%,
• Mn:
• not more than 1.3%, P:
• not more than 0.03%,
• S:
• not more than 0.007%, Al;
• not more than 0.1%,
• N:
• not more than 0.01%, and Ti:
• 0.14% to 0.30%,
• the contents of carbon, sulfur, nitrogen and titanium satisfying the inequality (1) below, the contents of niobium and boron as impurities being Nb:
• less than 0.03% and B:
• less than 0.0005%, the balance comprising Fe and inevitable impurities,
• the heating is performed at a heating temperature T (° C.) of not less than 1150°C., the heating temperature satisfying the inequality (2) below, the semi-manufactured steel material being held at the temperature range of not less than 1150°C. for 15 minutes or more,
• the hot rolling is performed with a total reduction ratio in a temperature range of 980°C. or below of not more than 40%,
• the finish rolling is performed at a finish rolling temperature of not less than 880°C.,
• the cooling is started within 3 seconds after the completion of finish rolling and is performed at an average cooling rate of 40°C/sec, to 200°C/sec., and
• the coiling is performed at a coiling temperature of 500°C. to 680°C.,
• wherein:
• 1.0≦([C]/12)/([Ti*]/48) (1)
• [Ti*]<10{−7000/(T+273)+2.75}/[C] (2)
• [Ti*]=[Ti]−3.4×[N]−1.5 ×[S]
• T:
• heating temperature (° C.) for the semi-manufactured steel material ([C], [S], [N] and [Ti]:
• contents (mass %) of the respective elements).