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:
Apr. 21, 2009
Filed:
Jun. 10, 2004
Nobuyuki Ishikawa, Chiyoda-ku, JP;
Toyohisa Shinmiya, Chiyoda-ku, JP;
Shigeru Endo, Chiyoda-ku, JP;
Ryuji Muraoka, Chiyoda-ku, JP;
Nobuyuki Ishikawa, Chiyoda-ku, JP;
Toyohisa Shinmiya, Chiyoda-ku, JP;
Shigeru Endo, Chiyoda-ku, JP;
Ryuji Muraoka, Chiyoda-ku, JP;
JFE Steel Corporation, , JP;
Abstract
A low yield ratio, high toughness steel plate which can be manufactured at high manufacturing efficiency and low cost, without increasing material cost by adding large amount of alloy elements and the like, and without degrading toughness of a welding heat affected zone, a low yield ratio, high strength and high toughness steel pipe using the steel plate, and a method for manufacturing those are provided. Specifically, the steel plate and the steel pipe contain C of 0.03% to 0.1%, Si of 0.01 to 0.5%, Mn of 1.2 to 2.5% and Al of 0.08% or less, wherein a metal structure is a substantially three-phase structure of ferrite, bainite and island martensite, and an area fraction of the island martensite is 3 to 20%, in addition, a complex carbide is precipitated in the ferrite phase.