| 摘要 |
<p>A high tensile steel product having a tensile strength of 600 MPa or higher and being excellent in delayed fracture resistance, characterized in that it has such a composition, in mass %, that C: 0.02 to 0.25 %, Si: 0.01 to 0.8 %, Mn: 0.5 to 2.0 %, Al: 0.005 to 0.1 %, N: 0.0005 to 0.008 %, P: 0. 03 % or less, S: 0.03 % or less, one or more of Mo, Nb, V and Ti: a specific amount, and the balance: Fe and inevitable impurities, and it contains precipitates containing one or more of Mo, Nb, V and Ti, and includes doposits having an average particle diameter of 20 nm or less in an amount of 5 pieces/250000 nm^2 or more; and a method for the production thereof.</p> |
