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:
Jul. 06, 2021

Filed:

Dec. 15, 2015
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Sota Goto, Kawasaki, JP;

Takatoshi Okabe, Handa, JP;

Yukihiko Okazaki, Handa, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 9/50 (2006.01); B21C 37/08 (2006.01); C21D 9/08 (2006.01); C22C 38/14 (2006.01); C21D 8/02 (2006.01); C22C 38/12 (2006.01); B21B 19/14 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); B21B 23/00 (2006.01); B23K 11/087 (2006.01); C21D 6/00 (2006.01); C21D 9/46 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/16 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/38 (2006.01); F16L 9/17 (2006.01); B23K 101/06 (2006.01); B23K 103/04 (2006.01);
U.S. Cl.
CPC ...
C21D 9/50 (2013.01); B21B 19/14 (2013.01); B21B 23/00 (2013.01); B21C 37/08 (2013.01); B23K 11/0873 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/02 (2013.01); C21D 8/0205 (2013.01); C21D 8/0263 (2013.01); C21D 9/08 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/004 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); F16L 9/17 (2013.01); B23K 2101/06 (2018.08); B23K 2103/04 (2018.08); C21D 2211/002 (2013.01);
Abstract

A high-strength high-toughness electric-resistance-welded steel pipe having high resistance to post-weld heat treatment is provided. The steel pipe having a composition including C: 0.01% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.0% to 2.2%, P: 0.03% or less, S: 0.005% or less, Al: 0.001% to 0.10%, N: 0.006% or less, Nb: 0.010% to 0.100%, and Ti: 0.001% to 0.050%. The steel pipe having a structure composed of a 90% or more by volume of a bainitic ferrite phase as a main phase and 10% or less (including 0%) by volume of a second phase. The bainitic ferrite phase having an average grain size of 10 μm or less, and the structure containing fine Nb precipitates having a particle size of less than 20 nm dispersed in a base material portion. The steel pipe having high strength, toughness, and high resistance that is maintained through post-weld heat treatment.


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