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. 11, 2012
Filed:
Oct. 22, 2008
Shuji Kozawa, Tokyo, JP;
Atsushi Mizuno, Muroran, JP;
Tatsuro Ochi, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a gear, continuously variable transmission, constant velocity joint, hub, or other steel part superior in surface fatigue strength compared with the past and method of production of the same, that is, provides a carbonitrided induction hardened steel part made of steel comprised of a specific composition of chemical ingredients and carbonitrided, then treated by induction hardening, the steel part characterized in that a surface N concentration is 0.1 to 0.8 mass %, a sum of an N concentration and C concentration is 1.0 to 2.0 mass %, an amount of surface residual austenite is less than 15 vol %, a depth of the incompletely hardened layer from the surface is less than 5 μm, and a surface X-ray diffraction half width is 6.0 degrees or more, and a method of production of the same.