| 摘要 |
PURPOSE: A high-strength thick plate and a manufacturing method thereof are provided to obtain superior low-temperature impact toughness by controlling alloy components, multi-stage controlled rolling, and cooling conditions. CONSTITUTION: A method for manufacturing a high-strength thick plate comprises the steps of: reheating a slab panel, which comprises C of 0.05-0.1wt.%, Si of 0.05-0.3wt.%, Mn of 1.4-2.0wt.%, P of 0.012wt.% or less, S of 0.003wt.% or less, Nb of 0.01-0.03wt.%, B of 0.0005-0.0015wt.%, Ti of 0.010-0.020wt.%, N of 0.005wt.% or less, and Fe and inevitable impurities of the remaining amount, to 1100-1200°C(S110), rolling the reheated panel first in a temperature range of 1100-1200°C(S120), rolling the first rolled panel secondly in a temperature range of 750-850°C(S130), and cooling the second rolled panel to a temperature range of 450-600°C(S140). [Reference numerals] (AA) Start; (BB) End; (S110) Reheating slab(1100-1200°C); (S120) First rolling(950-1050°C); (S130) Second rolling(750-850°C); (S140) Accelerated cooling(450-600°C)
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