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. 04, 2014
Filed:
Oct. 28, 2009
Hajime Ishikawa, Tokyo, JP;
Ryuji Uemori, Tokyo, JP;
Yoshiyuki Watanabe, Tokyo, JP;
Nobuhiko Mamada, Tokyo, JP;
Hajime Ishikawa, Tokyo, JP;
Ryuji Uemori, Tokyo, JP;
Yoshiyuki Watanabe, Tokyo, JP;
Nobuhiko Mamada, Tokyo, JP;
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Abstract
The present invention provides steel plate for line pipe excellent in strength and ductility and a method of production of the same. The steel plate has a steel composition containing, by mass %, C: 0.04 to 0.15%, Si: 0.05 to 0.60%, Mn: 0.80 to 1.80%, P: 0.020% or less, S: 0.010% or less, Nb: 0.01 to 0.08%, and Al: 0.003 to 0.08%, having a balance of iron and unavoidable impurities, and having a value of Ceq shown by the following formula <1> of 0.48 or less, comprised of a mixed structure of ferrite and pearlite or ferrite and pearlite partially containing bainite in which a ferrite percentage is 60 to 95%, having a yield strength of 450 MPa or more, and having an amount of hydrogen contained in the steel of 0.1 ppm or less:Ceq=C+Mn/6+(Cu+Ni)/15+(Cr+Mo+Nb+V+Ti)/5+5B  <1>.