The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 25, 1986
Filed:
Apr. 15, 1985
Masataka Suga, Tokyo, JP;
Makoto Yamada, Kanagawa, JP;
Kazuhide Takahashi, Kanagawa, JP;
Nobuhiro Iwasaki, Hiroshima, JP;
Kazuyuki Matsui, Hiroshima, JP;
Toru Izawa, Hiroshima, JP;
Itaru Watanabe, Kanagawa, JP;
Hisatoshi Tagawa, Kinosho, JP;
Nippon Kokan Kabushiki Kaisha, Tokyo, JP;
Abstract
The steel plate having a high tensile strength is manufactured from a steel consisting essentially of 0.04-0.16% by weight of C, 0.02-0.50% by weight of Si, 0.4-1.2% by weight of Mn, 0.2-5.0% by weight of Ni, 0.2-1.5% by weight of Cr, 0.2-1.0% by weight of Mo, 0.01-0.10% by weight of acid soluble Al, 0.03-0.15% by weight of one or more of V, Ti and Nb, 0.015% or less by weight of P, 0.006% or less by weight of S and the balance of iron and inherent impurities. The steel is heated to a temperature above a temperature at which carbo-nitrides of V and Nb and carbides of Ti become complete solid solution state, rolled with total reduction of 40% or more below 950.degree. C., quenched by simultaneous cooling immediately after completion of the rolling from a temperature above (A.sub.3 -50).degree.C. and tempered at a temperature lower than Ac.sub.1 temperature. The density of cooling water (W) for the quenching is detemined by the following equation (I) or (II) in accordance with the plate thickness (t):