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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 10570477 B1

PDFFull Text
Date of Patent:
Feb. 25, 2020

Filed:

Mar. 25, 2016

High-strength steel, method for manufacturing high-strength steel, steel pipe, and method for manufacturing steel pipe

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Shusaku Ota, Tokyo, JP;

Junji Shimamura, Fukuyama, JP;

Nobuyuki Ishikawa, Kawasaki, JP;

Shigeru Endo, Chiba, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

RatnerPrestia

Primary Examiner:

Anthony J Zimmer

Assistant Examiner:

Ricardo D Morales

Int. Cl.
CPC ...
C21D 9/46 (2006.01); C22C 38/58 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/38 (2006.01); C22C 38/26 (2006.01); C22C 38/14 (2006.01); C22C 38/12 (2006.01); C22C 38/34 (2006.01); C21D 8/10 (2006.01); C22C 38/28 (2006.01); C22C 38/18 (2006.01); C22C 38/24 (2006.01); B23K 9/028 (2006.01); C21D 9/08 (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); F16L 9/17 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B23K 9/0282 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C21D 8/10 (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 38/06 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/18 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (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 38/58 (2013.01); F16L 9/17 (2013.01); C21D 2211/002 (2013.01);
Abstract

High-strength steel having a specified chemical composition, wherein X (%) calculated by using equation (1):=0.35Cr+0.9Mo+12.5Nb+8V  (1)is 0.75% or more, wherein the symbols of chemical elements in equation (1) respectively denote the contents (mass %) of the corresponding chemical elements and wherein the symbol of a chemical element which is not included is assigned a value of 0, a microstructure having a bainite phase fraction of 50% or more, a dislocation density of 1.0×10/mor more after aging has been performed under the condition of a Larson-Miller parameter (LMP) of 15000, and a yield strength of 550 MPa or more before and after the aging is performed, as well as methods of manufacturing such high-strength steel, is disclosed. The high-strength steel can be used as a raw material for manufacturing large diameter steel pipe having the strength properties required for its use in steam transportation.

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