| abstract |
The cold forged steel sheet includes a hot rolled steel sheet, and the hot rolled steel sheet is, in mass%, C: 0.13 to 0.20%, Si: 0.01 to 0.8%, Mn: 0.1 to 2.5%, P: 0.003 to 0.030%, A: 0.0001 to 0.008%, Al: 0.01 to 0.07%, N: 0.0001 to 0.02%, and O: 0.0001 to 0.0030%, the remainder being made of Fe and unavoidable impurities, A represented by the following formula (1) The value is 0.0080 or less, and the thickness of the hot rolled steel sheet is 2 mm or more and 25 mm or less, and 4/10 t to 6/10 t when the plate thickness is t in the cross section of the plate thickness parallel to the rolling direction of the hot rolled steel sheet. In the cross section of the range, the area percentage of the pearlite band of 1 mm or more in length is equal to or less than the K value represented by the following formula (2). [Equation 1] &Quot; (2) " |