| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a steel sheet to be die-quenched superior in hot-punchability. Ž<P>SOLUTION: The steel sheet has a composition which includes, by mass%, 0.10% or more but less than 0.19% C, 0.15-0.5% Si, 1.0-1.8% Mn, 0.03% or less P, 0.020-0.050% S, 0.015-0.07% Al, 0.005% or less N, and Ti in the range of 0.05 to 0.15% so that Ti* which is defined by Ti*=Ti-3.4N-1.5S satisfies C-0.25Ti*≥0.10. Ti-containing sulfides in the steel sheet have diameters of which the average is 0.10 μm or more. In addition, the steel sheet has Ti-containing sulfides with diameters of 0.10 μm or more preferably in an amount of 30 pieces/mm<SP>2</SP>or more by average in a cross section of the steel sheet. The steel sheet may further include one or more elements selected from among Cr, B, Mo and W, in addition to the above composition. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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