| abstract |
An object of the present invention is to provide a steel sheet for heat treatment excellent in stability of strength against heat treatment conditions and delayed fracture resistance, and a method for producing the same. [Solution] Chemical component is mass%, C: 0.05 to 0.09 %, Si: 1% or less, Mn: 1.6 to 2.4%, P: 0.02% or less, S: 0.0 2% or less, sol.Al: 0.01 to 0.1%, N: 0.005% or less, B: 0.0003 A steel sheet for heat treatment, which contains ˜0.003% and Ti within a range satisfying the following inequality, the balance being substantially made of iron, and the average particle size of iron carbide being 2 μm or less. (48/32) S + (48/14) N ≦ Ti ≦ 2 {(48/32) S + (48/14) N} Here, the element symbol in the formula represents mass% of each element. Further, it may contain one or more of Cr: 0.1-2% and Mo: 0.1-2%. |