| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a hot rolled steel sheet which has excellent endurance fatigue resistance by the control of its composition and hot rolling conditions therefor, and the application of strain to the sheet thickness direction. SOLUTION: The hot rolled steel sheet having excellent fatigue resistance is produced from a slab having a composition containing, by mass, 0.02 to 0.07% C, 0.01 to 0.8% Si, 0.1 to 1.0% Mn, <=0.085% P, <=0.02% S, 0.015 to 0.2% Al and 0.001 to 0.008% N, and the balance Fe with inevitable impurities. In its production method, the finishing temperature in hot rolling is controlled to 805 to 900 deg.C, and the steel strip is cooled from the above temperature region to the range of 320 to 750 deg.C, and is coiled. The steel sheet is allowed to cool to <=100 deg.C, and, compression working strain of >=7% is applied to the sheet thickness direction.
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