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:
Jun. 05, 2012
Filed:
Oct. 30, 2007
Nao Yoshihara, Kobe, JP;
Nao Yoshihara, Kobe, JP;
Kobe Steel, Ltd., Kobe-shi, JP;
Abstract
An object of the preset invention is to provide a spring steel wire that: shows excellent wire drawability not only when it is used as a spring steel wire for cold-winding formed into a steel spring by applying quenching and tempering treatment after wiredrawing but also when it is used as a spring steel wire for cold-winding formed into a steel spring as it is wiredrawn; and secures a spring having an excellent fatigue characteristic after the spring steel wire is formed into the spring. The spring steel wire according to the present invention is a spring steel wire excellent in fatigue characteristic and wire drawability, wherein: the contents of C, Si, Mn, Cr, Ti, B, and other elements are specified; the contents (mass %) of B, Ti, and N satisfy the expression (1) below; the amount of solid solute B is in the range of 0.0005% to 0.0040%; the remainder in the spring steel wire is composed of Fe and unavoidable impurities; and the solid solute B concentrates at the grain boundaries of pearlite nodules,0.03≦B/(Ti/3.43−N)≦5.0  (1).