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:
Oct. 14, 1997
Filed:
Dec. 19, 1995
NKK Corporation, Tokyo, JP;
Abstract
A high-strength bainitic steel rail having an excellent damage resistance property, essentially consists of 0.2 to 0.5 wt % of C, 0.1 to 2.0 wt % of Si, 0.3 to 4.0 wt % of Mn, 0.035 wt % or less of P, 0.035 wt % of S, and 0.3 to 4.0 wt % of Cr, a balance being Fe, and having a micro structure made of a bainitic structure. This rail includes corner and head side portions having a Vickers hardness of Hv420 or higher, and a head top portion having a hardness of Hv420 or higher at a site 20-mm distant from a center of the head top portion in a width direction, wherein the center of the head top portion has such a hardness distribution that a hardness of the center of the head top portion is 10 to 70 lower in Vickers hardness than that of the site 20-mm distant from the center of the head top portion, a hardness of a section between the center of the head top portion and the site 20-mm away from the center in the width direction increases gradually from the center towards an outer side of the width direction, and a difference between an actual hardness of the section, and a hardness obtained by interpolating the hardness of the center of the head top portion and the hardness of the site 20-mm away from the center in the width direction by straight line, is 10 or less in Vickers hardness.