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. 03, 2012
Filed:
Jul. 24, 2007
Masaharu Ueda, Tokyo, JP;
Kazunori Seki, Tokyo, JP;
Takuya Sato, Tokyo, JP;
Takeshi Yamamoto, Tokyo, JP;
Masaharu Ueda, Tokyo, JP;
Kazunori Seki, Tokyo, JP;
Takuya Sato, Tokyo, JP;
Takeshi Yamamoto, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The invention provides a method for producing a pearlitic rail by rough hot rolling and finish hot rolling a billet. In the finish hot rolling, the billet is rolled at a rail head surface temperature in a range of not higher than 900° C. to not lower than the Artransformation point or Artransformation point to produce a head cumulative reduction of area of not less than 20%, where the reaction force ratio of the finish rolling is not less than 1.25. The finish hot rolled rail head surface is subjected to accelerated cooling or spontaneous cooling to a temperature of 550° C. or less at a cooling rate of 2 to 30° C./seconds, thereby refining the rail head structure to attain a hardness within a predetermined range, and improving rail wear resistance and ductility.