| 摘要 |
<p>A high-strength and high-toughness thick steel sheet and a manufacturing method thereof are provided to secure fracture toughness of structure under very low temperature condition by causing the steel sheet to have base material CTOD over 0.3mm. A high-strength and high-toughness thick steel sheet with superior base material CTOD property comprises C 0.06~0.12 weight%, Si 0.05~0.4 weight%, Mn 1.2~1.7 weight%, sol Al 0.005~0.05 weight%, Nb 0.005~0.03 weight%, Ti 0.005~0.03 weight%, N less than 0.008 weight%, P less than 0.012 weight%, S less than 0.005 weight%, and the rest Fe and inevitable impurities. The steel sheet also includes one or more selected from the group consisting of Cu less than 0.5 weight%, Ni less than 1.0 weight%, Cr less than 0.15 weight%, and Mo less than 0.15 weight%.</p> |
