| 摘要 |
PURPOSE: A high-strength steel plate and a manufacturing method thereof are provided to utilize the construction materials of an offshore structure constructed in low-temperature regions because the reduction of area in a thickness direction and the low-temperature impact toughness of a center part are excellent. CONSTITUTION: A manufacturing method of a high-strength steel plate is as follows: a step of manufacturing a slab board by continuously casting molten steel after the molten steel is vacuum-degassed (S110); a step of reheating the slab board within 950-1000°C and then primarily rolling the reheated slab board (S120); a step of secondarily rolling the primarily rolled slab board in a section where austenite is not recrystallized (S130); and a step of cooling the secondarily rolled slab board to 300-400°C at 2-6°C/sec (S140). [Reference numerals] (AA) Start; (BB) Finish; (S110) Vacuum degassing and continuous casting; (S120) Slab reheating/primary rolling; (S130) Secondary rolling; (S140) Cooling |
