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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 10920297 B1

PDFFull Text
Date of Patent:
Feb. 16, 2021

Filed:

Aug. 20, 2015

High-strength seamless steel pipe for oil country tubular goods and method of producing the same

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Masao Yuga, Handa, JP;

Yasuhide Ishiguro, Handa, JP;

Mitsuhiro Okatsu, Handa, JP;

Seiji Nabeshima, Kurashiki, JP;

Hiroki Ota, Handa, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

Oliff PLC

Primary Examiner:

Brian D Walck

Int. Cl.
CPC ...
C22C 38/02 (2006.01); C21D 1/18 (2006.01); C21D 8/10 (2006.01); C21D 9/08 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/14 (2006.01); C22C 38/18 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/32 (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 38/54 (2006.01); C21D 6/02 (2006.01); C22C 38/20 (2006.01); C22C 38/28 (2006.01); C22C 38/08 (2006.01); C22C 38/40 (2006.01);
U.S. Cl.
CPC ...
C21D 9/085 (2013.01); C21D 1/18 (2013.01); C21D 6/02 (2013.01); C21D 8/10 (2013.01); C21D 8/105 (2013.01); C21D 9/08 (2013.01); C22C 38/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/18 (2013.01); C22C 38/20 (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 38/40 (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 38/54 (2013.01); C21D 2211/001 (2013.01); C21D 2211/004 (2013.01); C21D 2211/008 (2013.01);
Abstract

A seamless steel pipe having a specific chemical composition. A ratio of Ti to N is in a range of 2.0 to 5.0. The steel pipe has a microstructure including tempered martensite having a volume ratio of 95% or more, and prior austenite grains having a grain size number of 8.5 or more. In a cross-section perpendicular to a rolling direction of the steel pipe a number of nitride-based inclusions having a particle size of 4 μm or more is 100 or less per 100 mm, a number of nitride-based inclusions having a particle size of less than 4 μm is 1000 or less per 100 mm, a number of oxide-based inclusions having a particle size of 4 μm or more is 40 or less per 100 mm, and a number of oxide-based inclusions having a particle size of less than 4 μm is 400 or less per 100 mm.

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