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.

Date of Patent:
Nov. 10, 2015

Filed:

Nov. 25, 2010
Applicants:

Nobuyuki Ishikawa, Fukuyama, JP;

Akihiko Tanizawa, Fukuyama, JP;

Hitoshi Sueyoshi, Fukuyama, JP;

Masayuki Horie, Fukuyama, JP;

Yasumitsu Kiyoto, Fukuyama, JP;

Nobuo Shikanai, Chiyoda-ku, JP;

Inventors:

Nobuyuki Ishikawa, Fukuyama, JP;

Akihiko Tanizawa, Fukuyama, JP;

Hitoshi Sueyoshi, Fukuyama, JP;

Masayuki Horie, Fukuyama, JP;

Yasumitsu Kiyoto, Fukuyama, JP;

Nobuo Shikanai, Chiyoda-ku, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C22C 38/02 (2006.01); B21C 37/08 (2006.01); B21C 37/30 (2006.01); C21D 1/20 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); F17D 1/16 (2006.01); C21D 8/10 (2006.01); C21D 9/50 (2006.01);
U.S. Cl.
CPC ...
C22C 38/02 (2013.01); B21C 37/08 (2013.01); B21C 37/30 (2013.01); C21D 1/20 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); F17D 1/16 (2013.01); C21D 8/10 (2013.01); C21D 9/50 (2013.01); C21D 2211/002 (2013.01); C21D 2211/008 (2013.01);
Abstract

Provided is a steel pipe for a linepipe having high compressive strength, a heavy wall thickness and sour gas resistance. The steel pipe has the composition which contains by mass % 0.02 to 0.06% C, 0.01 to 0.5% Si, 0.8 to 1.6% Mn, 0.012% or less P, 0.0015% or less S, 0.01 to 0.08% Al, 0.005 to 0.050% Nb, 0.005 to 0.025% Ti, 0.0005 to 0.0035% Ca, 0.0020 to 0.0060% N, and Fe and unavoidable impurities as a balance. The steel pipe has metal microstructure where a fraction of bainite is 80% or more, a fraction of M-A constituent is 2% or less and an average grain size of bainite is 5 μm or less.


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