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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.:

US 12522905 B1

PDFFull Text
Date of Patent:
Jan. 13, 2026

Filed:

Apr. 28, 2021

Duplex stainless steel seamless pipe

Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Mikiko Noguchi, Tokyo, JP;

Jun Nakamura, Tokyo, JP;

Masayuki Sagara, Tokyo, JP;

Daisuke Matsuo, Tokyo, JP;

Yoshihei Wakino, Tokyo, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Greer, Burns & Crain, Ltd.

Primary Examiner:

Jophy S Koshy

Int. Cl.
CPC ...
C22C 38/02 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/52 (2006.01); C22C 38/54 (2006.01); C22C 38/58 (2006.01); C22C 38/60 (2006.01); F16L 9/02 (2006.01); C21D 1/26 (2006.01); C21D 6/00 (2006.01); C21D 7/10 (2006.01); C21D 7/13 (2006.01); C21D 8/10 (2006.01); C21D 9/08 (2006.01);
U.S. Cl.
CPC ...
C22C 38/58 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/52 (2013.01); C22C 38/54 (2013.01); C22C 38/60 (2013.01); F16L 9/02 (2013.01); C21D 1/26 (2013.01); C21D 6/004 (2013.01); C21D 7/10 (2013.01); C21D 7/13 (2013.01); C21D 8/105 (2013.01); C21D 9/08 (2013.01); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01);
Abstract

The duplex stainless steel seamless pipe according to the present disclosure has the chemical composition described in the description and a microstructure consisting of 30 to 55% of ferrite, and austenite. In a square observation field of view region with sides of 250 μm including a center portion of the wall thickness and including a T direction and a C direction, a number of intersections NT which is a number of intersections between the line segment Tto Tdescribed in the description and ferrite interfaces is 65 or more. A number of intersections NC which is a number of intersections between the line segments Cto Cdescribed in the description and ferrite interfaces is 50 or more.

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