Title:
MANDREL MILL, ITS OPERATING METHOD, AND SEAMLESS PIPE MANUFACTURING METHOD
Document Type and Number:
WIPO Patent Application WO/2008/056540
Kind Code:
A1
Abstract:
Intended is to provide a mandrel mill capable of manufacturing a seamless pipe
having no flaw such as a necking flaw. The mandrel mill has a plurality of hole type
roll stands installed consecutively, and a mandrel bar (3) is arranged in the
forging roll die formed of those hole type roll stands, thereby to draw and roll
a hollow shell (2) continuously. A roll die (4) for at least a first stand and a second
stand is arranged to satisfy the conditions expressed by the following Formulas
(1) to (4): b ≤ 10a + 1.5... (1); b ≥ 10a - 0.2... (2); b ≤ -a
+ 1.5... (3); and b ≥ -a + 1.15... (4), wherein a = S/R1, and b = C/(R1 - S).
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Inventors:
SASAKI, Kenichi (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 5410041, JP)
Application Number:
JP2007/070732
Publication Date:
May 15, 2008
Filing Date:
October 24, 2007
Export Citation:
Assignee:
SUMITOMO METAL INDUSTRIES, LTD. (5-33, Kitahama 4-chome Chuo-ku, Osaka-sh, Osaka 41, 5410041, JP)
住友金属工業株式会社 (〒41 大阪府大阪市中央区北浜四丁目５番３３号 Osaka, 5410041, JP)
住友金属工業株式会社 (〒41 大阪府大阪市中央区北浜四丁目５番３３号 Osaka, 5410041, JP)
International Classes:
B21B17/02; B21B27/02; B21B17/00; B21B27/02
Attorney, Agent or Firm:
SUGIOKA, Kanji et al. (K. Sugioka Patent Office, 5-17-23 Higashinaniwa-ch, Amagasaki-shi Hyogo 92, 6600892, JP)
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