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:
Feb. 28, 2012

Filed:

Mar. 19, 2008
Applicants:

Naoya Hayakawa, Tokyo, JP;

Fumimaru Kawabata, Tokyo, JP;

Shuichi Sakaguchi, Tokyo, JP;

Mitsuhiro Okatsu, Tokyo, JP;

Makoto Ota, Kanagawa, JP;

Shigeki Nishiyama, Kanagawa, JP;

Kaoru Nagatani, Kanagawa, JP;

Keito Ishizaki, Kanagawa, JP;

Inventors:

Naoya Hayakawa, Tokyo, JP;

Fumimaru Kawabata, Tokyo, JP;

Shuichi Sakaguchi, Tokyo, JP;

Mitsuhiro Okatsu, Tokyo, JP;

Makoto Ota, Kanagawa, JP;

Shigeki Nishiyama, Kanagawa, JP;

Kaoru Nagatani, Kanagawa, JP;

Keito Ishizaki, Kanagawa, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B32B 15/04 (2006.01); B32B 15/18 (2006.01); B23K 9/18 (2006.01); B23K 25/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A high-strength steel pipe has a tensile strength of 800 MPa or more and includes a weld metal having high cold-cracking resistance and high low-temperature toughness, wherein the weld metal contains C: 0.04% to 0.09% by mass, Si: 0.32% to 0.50% by mass, Mn: 1.4% to 2.0% by mass, Cu: less than 0.5% by mass, Ni: more than 0.9% by mass but not more than 4.2% by mass, Mo: 0.4% to 1.5% by mass, Cr: less than 0.5% by mass, V: less than 0.2% by mass, and the remainder of Fe and incidental impurities, and CS values calculated from the weld metal components using the equation CS=5.1+1.4[Mo]−[Ni]−[Mn]−36.3[C] are equal to zero or more at both an internal surface and an external surface.


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