| 摘要 |
PROBLEM TO BE SOLVED: To provide a thick steel plate which has excellent fatigue-crack-propagation characteristics in a base metal and a weld zone, regardless of a crack proceeding direction, has excellent toughness, and can be manufactured without applying a high load to a rolling mill. SOLUTION: The thick steel plate superior in the fatigue-crack-propagation characteristics and toughness comprises, by mass%, 0.02-0.16% C, 0.05-0.5% Si, 0.005-0.060% Al, further one or more elements selected from 0.1-2.5% Mn, 0.1-2.0% Cu and 0.1-6.0% Ni so that a value of 2Mn+Cu+Ni is 3.5 to 6.0%, and the balance Fe with unavoidable impurities, and also includes, by a volume fraction, 5-20% of retained austenite with an average diameter of 0.1 to 0.5μm. COPYRIGHT: (C)2007,JPO&INPIT
|
