Invention Grant
- Patent Title: Steering rack comprising steel bar with rack teeth
- Patent Title (中): 转向架包括带齿条齿的钢筋
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Application No.: US10558359Application Date: 2004-05-27
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Publication No.: US07662245B2Publication Date: 2010-02-16
- Inventor: Atsuhiko Ohta , Makoto Kamei , Kazuhiro Watanabe , Yukinori Kanaike , Osamu Tsukamoto , Masakazu Ikeda , Gorou Anan , Hiroshi Itoziri
- Applicant: Atsuhiko Ohta , Makoto Kamei , Kazuhiro Watanabe , Yukinori Kanaike , Osamu Tsukamoto , Masakazu Ikeda , Gorou Anan , Hiroshi Itoziri
- Applicant Address: JP Osaka
- Assignee: Koyo Seiko Co., Ltd.
- Current Assignee: Koyo Seiko Co., Ltd.
- Current Assignee Address: JP Osaka
- Agency: Rabin and Berdo, P.C.
- Priority: JP2003-148906 20030527; JP2003-157029 20030602
- International Application: PCT/JP2004/007678 WO 20040527
- International Announcement: WO2004/106574 WO 20041209
- Main IPC: C22C38/14
- IPC: C22C38/14 ; C22C38/04 ; C22C38/02 ; C22C38/06

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.
Public/Granted literature
- US20070113698A1 Steel bar for steering rack manufacturing method of the same, and steering rack usnig the same Public/Granted day:2007-05-24
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