Title:
PROCESS FOR PRODUCING PEARLITIC RAIL EXCELLENT IN WEARING RESISTANCE AND DUCTILITY
Document Type and Number:
WIPO Patent Application WO/2008/013300
Kind Code:
A1
Abstract:
A process for producing a pearlitic rail by subjecting a steel billet containing, in
terms of mass%, 0.65-1.20% C, 0.05-2.00% Si, and 0.05-2.00% Mn, the remainder being
iron and incidental impurities, to at least rough rolling and finish rolling. In
the finish rolling, the work is rolled at a rail head surface temperature which is
not higher than 900°C and not lower than transformation point Ar3 or
transformation point Arcm so as to result in a cumulative head area reduction
of 20% or higher and a reaction force ratio of 1.25 or higher. The rail head surface
after the finish rolling is cooled to at least 550°C at a cooling rate of 2-30
°C/sec by accelerated cooling or natural cooling to thereby reduce the
grain size of the structure in the rail head and regulate the hardness to a value
in a given range. Thus, the rail can have improved wearing resistance and ductility.
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Inventors:
UEDA, Masaharu (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
上田正治 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
SEKI, Kazunori (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
関和典 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
上田正治 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
SEKI, Kazunori (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
関和典 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
Application Number:
JP2007/064839
Publication Date:
January 31, 2008
Filing Date:
July 24, 2007
Export Citation:
Assignee:
NIPPON STEEL CORPORATION (6-3 Otemachi 2-chome, Chiyoda-ku Tokyo, 71, 1008071, JP)
新日本製鐵株式会社 (〒71 東京都千代田区大手町二丁目６番３号 Tokyo, 1008071, JP)
UEDA, Masaharu (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
上田正治 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
SEKI, Kazunori (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
新日本製鐵株式会社 (〒71 東京都千代田区大手町二丁目６番３号 Tokyo, 1008071, JP)
UEDA, Masaharu (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
上田正治 (〒71 東京都千代田区大手町二丁目６番３号新日本製鐵株式会社内 Tokyo, 1008071, JP)
SEKI, Kazunori (6-3 Otemachi 2-chome, Chiyoda-k, Tokyo 71, 1008071, JP)
International Classes:
C21D8/00; B21B1/085; B21B3/00; C21D9/04; C22C38/00; C22C38/04; C22C38/58
Attorney, Agent or Firm:
AOKI, Atsushi et al. (SEIWA PATENT & LAW, Toranomon 37 Mori Bldg.5-1, Toranomon 3-chome,Minato-k, Tokyo 23, 1058423, JP)
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