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. 09, 2008
Filed:
Jan. 27, 2004
Shingo Yamasaki, Kimitsu, JP;
Seiki Nishida, Kimitsu, JP;
Toshiyuki Kajitani, Kimitsu, JP;
Wataru Yamada, Kimitsu, JP;
Yoshitaka Nishikawa, Kimitsu, JP;
Nariyasu Muroga, Kimitsu, JP;
Nobuyuki Komiya, Kimitsu, JP;
Shingo Yamasaki, Kimitsu, JP;
Seiki Nishida, Kimitsu, JP;
Toshiyuki Kajitani, Kimitsu, JP;
Wataru Yamada, Kimitsu, JP;
Yoshitaka Nishikawa, Kimitsu, JP;
Nariyasu Muroga, Kimitsu, JP;
Nobuyuki Komiya, Kimitsu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a high strength, high toughness steel wire rod useful for a PC steel wire, galvanized steel strands, spring use steel wire, cables for suspension bridges, etc. By hot rolling, then directly patenting or reaustenitizing, then patenting a high carbon steel wire rod of a specific chemical composition of the steel and chemical composition, size, and numerical density of inclusions, piano wire rod or high carbon steel wire rod having a structure of mainly pearlite, having an average value of the proeutectoid cementite area ratio of 5% or less in a center region of less than 20% of the wire rod diameter from the center of the wire rod, having a micromartensite size of the C section of 100 μm or less, having a tensile strength of the 170 kgf/mmclass or more, and having a drawing ratio at break of 30% or more is obtained.