| 摘要 |
Disclosed are a high strength steel plate with excellent CTOD properties, and a method for manufacturing the same. According to the present invention, the method for manufacturing a high strength steel plate comprises: a step for reheating a slab plate including in wt%, 0.02-0.12% of carbon (C), less than or equal to 0.5% of silicon (Si), 1.0-1.8% of manganese (Mn), less than or equal to 0.01% of phosphorus (P), less than or equal to 0.01% of sulfur (S), 0.1-0.4% of chrome (Cr), 0.2-0.8% of nickel (Ni), 0.15-1.0% of molybdenum (Mo), less than or equal to 0.06% of aluminum (Al), 0.2-0.5% of copper (Cu), less than or equal to 0.03% of titanium (Ti), 0.005-0.05% of niobium (Nb), 0.005-0.05% of vanadium (V), 0.0005-0.004% of boron (B), less than or equal to 0.015% of stibium (Sb), less than or equal to 0.015% of tin (Sn), less than or equal to 0.007% of nitrogen (N), residual iron (Fe), and unavoidable impurities at 900-1000°C; a step for primary rolling the reheated plate in an austenite recrystallization area; a step for secondary rolling the primary rolled plate at the temperature above Ar3; and a step for cooling the secondary rolled plate at 250-400°C. [Reference numerals] (AA) Start; (BB) End; (S110) Reheating a slab (900-1000°C); (S120) Primary rolling; (S130) Secondary rolling; (S140) Cooling |
