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Title:
PROCESS FOR PRODUCING HIGH-Cr SEAMLESS PIPE
Document Type and Number:
WIPO Patent Application WO/2007/100042
Kind Code:
A1
Abstract:
A billet containing, by mass, 8.0 to 16.0% Cr whose value of the formula: Cr+4Si-(22C+0.5Mn+1.5Ni+30N) wherein the atomic symbols represent the mass% contents of respective constituent elements in steel is 9.0% or less is heated by means of a heating furnace conditioned so as to have the soaking temperature ranging from 1100° to 1300°C and allow the in-furnace time (min) to satisfy the relationship: 0.5 × billet diameter (mm) or more. Thereafter, by means of a centering machine capable of making a center hole of diameter of 0.34 × billet diameter (mm) or more at the piercing-starting-side end face of the billet by punch of 60° to 110° punching angle, a center hole is made at the piercing-starting-side end face of the billet, followed by piercing rolling by an inclined roll piercing machine of 8.0% or below plug distal-end draft ratio. The thus produced high-Cr seamless pipe realizes reduction of internal-surface defects and ensures excellent internal-surface properties.

Inventors:
OHE, Taro (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 5410041, JP)
大江 太郎 (〒41 大阪府大阪市中央区北浜四丁目5番33号 住友金属工業株式会社内 Osaka, 5410041, JP)
Application Number:
JP2007/053916
Publication Date:
September 07, 2007
Filing Date:
March 01, 2007
Export Citation:
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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)
OHE, Taro (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 5410041, JP)
International Classes:
B21B19/04; B21B23/00; C21D9/00; C22C38/00; C22C38/50; C22C38/54
Domestic Patent References:
2005-12-08
Foreign References:
JPH01181905A1989-07-19
JPS5372763A1978-06-28
JPS59208055A1984-11-26
JPS63281705A1988-11-18
JPH04224659A1992-08-13
JPH0569011A1993-03-23
JP2003003212A2003-01-08
JP2004043935A2004-02-12
JP2004082174A2004-03-18
Other References:
See also references of EP 1990107A1
Attorney, Agent or Firm:
SUGIOKA, Kanji et al. (K. Sugioka Patent Office, Amagasaki Building 5-17-23, Higashinaniwa-ch, Amagasaki-shi Hyogo 92, 6600892, JP)
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