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.:
Date of Patent:
Aug. 07, 2018
Filed:
Sep. 11, 2014
Jfe Steel Corporation, Tokyo, JP;
Sumihatsu Co., Ltd., Tokyo, JP;
Nhk Spring Co., Ltd., Yokohama-shi, Kanagawa, JP;
Minoru Honjo, Tokyo, JP;
Kiyoshi Uwai, Tokyo, JP;
Shigeru Endo, Tokyo, JP;
Katsutoshi Yamashita, Tokyo, JP;
Koei Tsuru, Yuki, JP;
Keiichi Fujie, Sakuragawa, JP;
Akira Tange, Yokohama, JP;
JFE STEEL CORPORATION, Tokyo, JP;
SUMIHATSU CO., LTD., Tokyo, JP;
NHK SPRING CO., LTD., Yokohama-shi, JP;
Abstract
Provided is high strength steel for springs that, compared to conventional high strength steel for springs, has excellent decarburization resistance and scale exfoliation property, by optimization of the added amounts of C, Si, Mn, and Cr as well as of Sb and Sn. The steel for springs contains C: more than 0.45 mass % and less than 0.65 mass %, Si: 0.15 mass % or more and 0.70 mass % or less, Mn: 0.10 mass % or more and 1.00 mass % or less, Cr: 0.20 mass % or more and 1.50 mass % or less, P: 0.025 mass % or less, S: 0.025 mass % or less, O: 0.0015 mass % or less, Sb: 0.010 mass % or more and less than 0.030 mass %, and Sn: 0.010 mass % or more and 0.030 mass % or less, under predetermined conditions.