| 摘要 |
<p>PURPOSE: A thick plate and a manufacturing method thereof are provided to obtain an average impact toughness of 250J or greater at yield strength of 420MPa or greater and the temperature of -40°C. CONSTITUTION: A method for manufacturing a thick plate comprises the steps of: reheating a slab panel, which comprises C of 0.065-0.95wt.%, Si of 0.25-0.35wt.%, Mn of 1.50-1.60wt.%, Al of 0.02-0.06wt.%, Ti of 0.01-0.02wt.%, Nb of 0.01-0.03wt.%, Ni of 0.2-0.4wt.%, and Fe and inevitable impurities of the remaining amount(S110), rolling the reheated panel in an austenite recrystallization range first(S120), rolling the first rolled panel in a non-recrystallization range below the austenite recrystallization stop temperature secondly(S130), and cooling the second rolled panel to a banite temperature range(S140). [Reference numerals] (AA) Start; (BB) Air cooling; (CC) End; (S110) Reheating slab; (S120) First rolling; (S130) Second rolling; (S140) Cooling</p> |
