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:
Jan. 29, 2013
Filed:
Dec. 04, 2008
Rikio Chijiiwa, Kawasaki, JP;
Ryuji Uemori, Tokyo, JP;
Yoshiyuki Watanabe, Tokyo, JP;
Kazuhiro Fukunaga, Tokyo, JP;
Akihiko Kojima, Tokyo, JP;
Yoshihide Nagai, Tokyo, JP;
Rikio Chijiiwa, Kawasaki, JP;
Ryuji Uemori, Tokyo, JP;
Yoshiyuki Watanabe, Tokyo, JP;
Kazuhiro Fukunaga, Tokyo, JP;
Akihiko Kojima, Tokyo, JP;
Yoshihide Nagai, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a high strength steel having unprecedentedly superior CTOD (fracture toughness) properties satisfying not only the CTOD properties of the FL zone at −60° C., but also the CTOD properties of the ICHAZ zone in small and medium heat input multilayer welding, etc.; and a method of production of the same. The steel of the present invention is steel superior in CTOD properties of the heat-affected zone containing, by mass %, C: 0.015 to 0.045%, Si: 0.05 to 0.2%, Mn: 1.5 to 2.0%, Cu: 0.25 to 0.5%, Ni: 0.7 to 1.5%, P: 0.008% or less, S: 0.005% or less, Al: 0.004% or less, Ti: 0.005 to 0.015%, Nb: 0.005% or less, O: 0.0015 to 0.0035%, and N: 0.002 to 0.006%, P: 0.065 or less, CeqH: 0.235 or less and the balance consisting of Fe and unavoidable impurities.