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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 10494704 B1

PDFFull Text
Date of Patent:
Dec. 03, 2019

Filed:

Jan. 22, 2016

Rail

Applicant:

Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;

Inventors:

Masaharu Ueda, Kitakyushu, JP;

Takuya Tanahashi, Kitakyushu, JP;

Teruhisa Miyazaki, Kitakyushu, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Birch, Stewart, Kolasch & Birch, LLP

Primary Examiner:

Robert J McCarry, Jr

Int. Cl.
CPC ...
C22C 38/24 (2006.01); C21D 9/04 (2006.01); C22C 38/00 (2006.01); C22C 38/54 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C21D 9/46 (2006.01); C22C 38/06 (2006.01); C22C 38/18 (2006.01); C21D 8/00 (2006.01);
U.S. Cl.
CPC ...
C22C 38/24 (2013.01); C21D 9/04 (2013.01); C21D 9/46 (2013.01); C22C 38/00 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/18 (2013.01); C22C 38/54 (2013.01); C21D 8/00 (2013.01); C21D 2211/009 (2013.01); Y02P 10/212 (2015.11);
Abstract

The present invention relates to a rail which has a predetermined chemical composition and satisfies expressions of 1.00<Mn/Cr≤4.00 and 0.30≤0.25×Mn+Cr≤1.00 and in which a structure to a depth of 25 mm from an outer surface of a head portion as the origin includes 95% or greater of a pearlite structure, the hardness of the structure is in a range of Hv 350 to 480, 50 to 500 V carbonitride having an average grain size of 5 to 20 nm are present per 1.0 μmof an area to be inspected in a transverse cross section at a position having a depth of 25 mm from the outer surface of the head portion, and the value obtained by subtracting the hardness of the position having the depth of 25 mm from the outer surface of the head portion from the hardness of the position having a depth of 2 mm from the outer surface of the head portion is in a range of Hv 0 to Hv 40.

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