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:
Mar. 29, 2011
Filed:
Apr. 13, 2007
Kiyotaka Nakashima, Tokyo, JP;
Masanori Minagawa, Tokyo, JP;
Kouji Ishida, Tokyo, JP;
Akira Ito, Tokyo, JP;
Kiyotaka Nakashima, Tokyo, JP;
Masanori Minagawa, Tokyo, JP;
Kouji Ishida, Tokyo, JP;
Akira Ito, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides high strength thick steel plate superior in crack arrestability high in strength, free of deterioration of HAZ toughness, and free of anisotropy, that steel plate containing, by mass %, C: 0.03 to 0.15%, Si: 0.1 to 0.5%, Mn: 0.5 to 2.0%, P: ≦0.02%, S: ≦0.01%, Al: 0.001 to 0.1%, Ti: 0.005 to 0.02%, Ni: 0.15 to 2%, and N: 0.001 to 0.008% and having a balance of iron and unavoidable impurities as chemical components, having a microstructure of a ferrite and/or pearlite structure with bainite as a matrix phase, and having an average circle equivalent diameter of crystal grains with a crystal misorientation angle of 15° or more of 15 μm or less in the regions of 10% of plate thickness from the front and rear surfaces and of 40 μm or less in the other region including the center part of plate thickness.