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:
Apr. 14, 2015
Filed:
Aug. 15, 2008
Takuya Kochi, Kobe, JP;
Shogo Murakami, Kobe, JP;
Takeshi Kuroda, Kakogawa, JP;
Hiromichi Tsuchiya, Kakogawa, JP;
Takuya Kochi, Kobe, JP;
Shogo Murakami, Kobe, JP;
Takeshi Kuroda, Kakogawa, JP;
Hiromichi Tsuchiya, Kakogawa, JP;
Kobe Steel, Ltd., Kobe-shi, JP;
Abstract
Disclosed is a spring steel wire rod that comprises C in a range of 0.35 to 0.65% (mass %, the same applies to respective elements described hereinafter), Si in a range of 1.4 to 2.2%, Mn in a range of 0.10 to 1.0%, Cr in a range of 0.1 to 2.0%, P not more than 0.025% (0% excluded), and S not more than 0.025% (0% excluded), balance comprising iron, and unavoidable impurities, wherein an average grain size Dc of a central part of the steel wire rod is not more than 80 μm while an average grain size Ds of a surface layer part of the steel wire rod is not less than 3.0 μm.