| 摘要 |
<p>A high-strength steel sheet is provided which, even when subjected to long-term stress-relief annealing after welding, decreases little in strength (that is, has satisfactory resistance to stress-relief annealing) and which is excellent also in the low-temperature toughness of the base material and HAZ after the SR treatment. The high-strength steel sheet contains 0.05-0.18% carbon (in terms of mass%; the same applies hereinafter), 0.10-0.50% silicon, 1.2-2.0% manganese, 0.01-0.10% aluminum, 0.05-0.30% chromium, 0.008-0.025% titanium, and 0.01-0.05% vanadium, with the remainder being iron and incidental impurities. The content of phosphorus among the incidental impurities has been reduced to 0.008% or lower. The steel sheet satisfies a given relationship.</p> |
