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:
Jul. 22, 2003
Filed:
Sep. 27, 2000
Seiki Nishida, Kimitsu, JP;
Atsuhiko Yoshie, Futtsu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention relates to a wire rod for high fatigue-strength steel wire of small diameter, and a wire rod used in steel wire obtained by twisting these together, a steel wire and a method of producing the same. The wire rod for steel wire and the steel wire have a microstructure obtained by controlled cooling following hot rolling of a steel, containing, in mass %, 0.6-1.3% of C, 0.1-1.5% of Si and 0.2-1.5% of Mn wherein the area ratio of upper bainite measured in a cross-section thereof is 5-50%, the remainder being substantially composed of pearlite. The production method thereof comprises drawing and patenting a wire rod of 5-16 mm diameter having the aforesaid composition to obtain a wire of 0.8-2.8 mm diameter, then austenitizing the wire, quenching it to a temperature range of 500-560° C. for conducting isothermal transformation, thereby adjusting it to a steel microstructure wherein the area fraction of upper bainite is 5-50%, the remainder being substantially composed of pearlite, and then conducting brass plating and drawing to obtain a wire of 0.05-1.0 mm diameter.