| 摘要 |
<p>PURPOSE: A thick steel plate with homogeneous low temperature toughness on the surface and in the center part of thickness and a manufacturing method thereof are provided to be broadly utilized for such as a ship construction with an excellent low temperature toughness at the center by controlling alloy components and a production process condition, thereby satisfying 510-660MPa of tensile strength and more than 300J of impact toughness at -40°C. CONSTITUTION: A manufacturing method of a thick steel plate with homogeneous low temperature toughness on the surface and in the center part of thickness comprise the following steps: reheating(S110) a slab plate material to 1100-1200°C; firstly rolling(S120) the reheated slab plate material in the re-crystallization area; secondly rolling(S130) the previously rolled slab plate material in the re-crystallization area by using multiple rolling passes; and cooling(S140) the secondly rolled plate material to 300-450°C. The steel slab plate material is composed of, in wt %: C 0.065-0.095, Si 0.10-0.30, Mn 1.45-1.60.0, P less than 0.012, S less than 0.003, Al 0.015-0.05, Ti 0.005-0.02, Nb 0.01-0.03, N less than 50ppm, and other unavoidable impurities including Fe. The steel slab board includes at least one component among 0.20-0.35wt % of Cu and 0.25-0.40 wt % of Ni. [Reference numerals] (AA) Start; (BB) End; (S110) Reheating slab(1100-1200°C); (S120) First rolling(930-1030°C); (S130) Second rolling(780-850°C, accumulated reduction ratio 40-60%); (S140) Cooling(300-450°C, 2-6°C/sec)</p> |
