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:
Mar. 19, 2019

Filed:

Jun. 04, 2015
Applicant:

Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;

Inventors:

Atsushi Soma, Wakayama, JP;

Yuji Arai, Amagasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C21D 9/14 (2006.01); C21D 8/10 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/26 (2006.01); C21D 9/08 (2006.01); C22C 38/06 (2006.01);
U.S. Cl.
CPC ...
C22C 38/32 (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 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C21D 2211/003 (2013.01); C21D 2211/004 (2013.01); C21D 2211/008 (2013.01);
Abstract

A low-alloy steel pipe includes C: 0.15% to less than 0.30%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: at most 0.030%, S: at most 0.0050%, Al: 0.005 to 0.100%, O: at most 0.005%, N: at most 0.007%, Cr: 0.10% to less than 1.00%, Mo: 1.0% to not more than 2.5%, V: 0.01 to 0.30%, Ti: 0.002 to 0.009%. Nb: 0 to 0.050%, B: 0 to 0.0050%, Ca: 0 to 0.0050%, Mo/Cr≥2.0, and the balance being Fe and impurities. The pipe has a crystal grain size number of 7.0 or more, 50 or more particles of cementite based on equivalent circle diameter and area of the matrix, MC-based alloy carbide in a number density of not less than 25/μm, and a yield strength of 758 MPa or more.


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