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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 10060015 B1

PDFFull Text
Date of Patent:
Aug. 28, 2018

Filed:

Sep. 16, 2014

Steel for high-strength bolts which has excellent delayed fracture resistance and bolt formability, and bolt

Applicant:

Kobe Steel, Ltd., Kobe-shi, JP;

Inventors:

Yosuke Matsumoto, Kobe, JP;

Atsushi Inada, Kobe, JP;

Masamichi Chiba, Kobe, JP;

Yoshimasa Ureshino, Toyota, JP;

Reiko Kato, Toyota, JP;

Assignee:

Kobe Steel, Ltd., Kobe-shi, JP;

Attorney:

Oblon, McClelland, Maier & Neustadt, L.L.P.

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/50 (2006.01); C21D 9/00 (2006.01); C21D 1/25 (2006.01); F16B 31/06 (2006.01); C22C 38/00 (2006.01); C21D 1/18 (2006.01); C21D 6/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01);
U.S. Cl.
CPC ...
C22C 38/50 (2013.01); C21D 1/18 (2013.01); C21D 1/25 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 9/0093 (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 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); F16B 31/06 (2013.01);
Abstract

To provide a steel for high-strength bolts, which can exhibit the sufficient delayed fracture resistance under the severe environment, and also has excellent bolt formability. The steel for high-strength bolts of the present invention includes C: 0.10 to 0.30%; and Ni: 0.4 to 0.7%, with the chemical composition being appropriately adjust, and satisfies the following formulas (1) and (2):0.85≤[C]+[Si]/7+[Mn]/5+[Ni]/20+[Cr]/9+[Mo]/2≤1.3  (1)[C]−(0.07×[Mo]+0.20×[V])≤0.20  (2).

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