THICK STEEL PLATE FOR MARINE STRUCTURE, AND METHOD FOR PRODUCING THE SAME

• Main Authors: KAMIMURA TAKAYUKI, SUZUKI SHUICHI, KAWABATA TOMOYA, YUKI HIDEAKI, KAJIMA KAZUYUKI, SAKAIBORI HIDEO, OKUBO TAKESHI, KUBO SATOSHI
• Format: Patent
• Language: English
• Published: 02.08.2012
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide a thick steel plate for a marine structure which has excellent fracture toughness and excellent corrosion resistance under a high-chloride environment by an inexpensive and simple means.SOLUTION: The thick steel plate for a marine structure includes, by mass, 0.02-0.1% C, 0.03-0.5% Si, 0.5-2.0% Mn, 0.002-0.08% Al, 0.001-0.008% N, 0.003-0.05% Nb, 0.003-0.05% Ti, 0.03-0.50% Sn and the balance Fe with impurities. The microstructure of the steel plate is includes ferrite transformed from non-recrystallized austenite and a second hard phase, in which the ferrite particle size is 2-15 μm, and the aspect ratio of the second hard phase is less than 10. The thick steel plate may further contain one or more elements selected from Ni, Cr, Mo, V and Cu.