| 摘要 |
A steel sheet for obtaining a member which is excellent in fatigue characteristics equal to ordinary high strength steel sheet of the same strength even if applying the hot stamping process and a method of production of the same are provided. Steel sheet for a hot stamped member which includes composition which contains, by mass %, C: 0.15 to 0.35%, Si: 0.01 to 1.0%, Mn: 0.3 to 2.3%, Al: 0.01 to 0.5%, and a balance of Fe and unavoidable impurities, and limit the impurities to P: 0.03% or less, S: 0.02% or less, and N: 0.1% or less, wherein that a standard error of Vicker's hardness at a position of 20 mum from the steel sheet surface in the sheet thickness direction is 20 or less. This steel sheet is produced by a recrystallization-annealing step of a first stage of heating a cold rolled steel sheet, which is obtained by hot rolling steel containing the above composition and then cold rolling it, by an average heating rate of 8 to 25° C./sec from room temperature to 600 to 700° C., then a second stage of heating by an average heating rate of 1 to 7° C./sec to 720 to 820° C. |
