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:
Dec. 02, 2014
Filed:
Sep. 30, 2008
Tomoko Sugimura, Kobe, JP;
Koichi Sakamoto, Kobe, JP;
Atsuhiko Yoshida, Kobe, JP;
Kei Masumoto, Kobe, JP;
Tomoko Sugimura, Kobe, JP;
Koichi Sakamoto, Kobe, JP;
Atsuhiko Yoshida, Kobe, JP;
Kei Masumoto, Kobe, JP;
Kobe Steel, Ltd., Kobe-shi, JP;
Abstract
Disclosed is a spring steel which contains, by mass, 1.2% or less C; 0.1% to 2% Mn; 0.2% to 3% Si; 0.0003% to 0.005% Al; to 8 ppm Li; 30 ppm or less (excluding 0 ppm) Ca; and 10 ppm or less (excluding 0 ppm) Mg. The steel contains oxide inclusions satisfying the following conditions (1) to (3) in a number of 1×10or more per square millimeter: (1) containing a total of 80 percent by mass or more of AlOand SiObased on the inclusion composition excluding LiO; (2) having a ratio by mass of AlOto SiOof from 1:4 to 2:3; and (3) containing lithium (Li). The spring steel gives a spring that exhibits superior fatigue properties without strict control of the average composition of inclusions.