| 摘要 |
A method for producing a high strength steel plate, which can satisfy both weldability and strength of the steel plate even in a thick steel plate with a thickness of 50 mm or more, and improves low temperature toughness of the steel product remarkably by microstructural refinement of a steel product, is provided. A method for producing a high strength steel plate having excellent weldability and low temperature toughness comprises: finish rolling a steel product comprising, by weight percent, 0.05 to 0.1% of C, 0.15 to 0.35% of Si, 1.3 to 1.6% of Mn, 0.005 to 0.017% of Ti, 0.005 to 0.025% of Nb, 0.005 to 0.060% of soluble Al and the balance of Fe and other inevitable impurities to a reduction ratio of 30% or more at a temperature from not more than an austenite recrystallization temperature to not less than Ar3; initiating cooling of the finish rolled steel product at a cooling rate of 3 deg.C/sec or more at a temperature of Ar3 or more; and stopping cooling of the steel product in a temperature range of 400 to 550 deg.C. |
