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:
Feb. 16, 2010
Filed:
May. 27, 2004
Atsuhiko Ohta, Osaka, JP;
Makoto Kamei, Osaka, JP;
Kazuhiro Watanabe, Osaka, JP;
Yukinori Kanaike, Osaka, JP;
Osamu Tsukamoto, Osaka, JP;
Masakazu Ikeda, Kobe, JP;
Gorou Anan, Kobe, JP;
Hiroshi Itoziri, Kobe, JP;
Atsuhiko Ohta, Osaka, JP;
Makoto Kamei, Osaka, JP;
Kazuhiro Watanabe, Osaka, JP;
Yukinori Kanaike, Osaka, JP;
Osamu Tsukamoto, Osaka, JP;
Masakazu Ikeda, Kobe, JP;
Gorou Anan, Kobe, JP;
Hiroshi Itoziri, Kobe, JP;
Koyo Seiko Co., Ltd., Osaka, JP;
Abstract
A steel bar for a steering rack that contains 0.50 to 0.60% by mass of C, 0.05 to 0.5% by mass of Si, 0.2 to 1.5% by mass of Mn, 0.0005 to 0.003% by mass of B, 0.005 to 0.05% by mass of Ti, 0.0005 to 0.1% by mass of Al, and 0.002 to 0.02% by mass of N is provided. Given D as a diameter of the steel bar, then the steel bar is adjusted in such a manner that quenched and tempered structures in a portion of the steel bar at a depth of D/4 from a surface satisfy conditions I), II), and III) as follows: I) a sum of a tempered bainitic structure and a tempered martensitic structure accounts for 30 to 100% in area percentage; II) a regenerated perlite structure accounts for 0 to 50% in area percentage; and III) a sum of the tempered bainitic structure, the tempered martensitic structure, and the regenerated perlite structure accounts for 50 to 100% in area percentage.