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:
Jul. 05, 2011
Filed:
Jul. 19, 2007
Masaharu Ueda, Kitakyushu, JP;
Koichiro Matsushita, Kitakyushu, JP;
Kazuo Fujita, Kitakyushu, JP;
Katsuya Iwano, Kitakyushu, JP;
Koichi Uchino, Kitakyushu, JP;
Takashi Morohoshi, Kitakyushu, JP;
Akira Kobayashi, Kitakyushu, JP;
Masaharu Ueda, Kitakyushu, JP;
Koichiro Matsushita, Kitakyushu, JP;
Kazuo Fujita, Kitakyushu, JP;
Katsuya Iwano, Kitakyushu, JP;
Koichi Uchino, Kitakyushu, JP;
Takashi Morohoshi, Kitakyushu, JP;
Akira Kobayashi, Kitakyushu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention is: a pearlitic steel rail excellent in wear resistance and ductility, characterized in that, in a steel rail having pearlite structure containing, in mass, 0.65 to 1.40% C, the number of the pearlite blocks having grain sizes in the range from 1 to 15 μm is 200 or more per 0.2 mmof an observation field at least in a part of the region down to a depth of 10 mm from the surface of the corners and top of the head portion; and a method for producing a pearlitic steel rail excellent in wear resistance and ductility, characterized by, in the hot rolling of said steel rail, applying finish rolling so that the temperature of the rail surface may be in the range from 850° C. to 1,000° C. and the sectional area reduction ratio at the final pass may be 6% or more, and then applying accelerated cooling to the head portion of said rail at a cooling rate in the range from 1 to 30° C./sec. from the austenite temperature range to at least 550° C.