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Title:
PROCESS FOR PRODUCING SEAMLESS PIPE
Document Type and Number:
WIPO Patent Application WO/2007/110930
Kind Code:
A1
Abstract:
A process for producing a seamless pipe characterized by including a continuous casting step in which a round billet is cast in which the whole region in a central part having a diameter of at least 60 mm in the cross section is constituted of an isometric crystal structure and which has a carbon content of 0.1 mass% or lower and a diameter in terms of cross-section diameter beyond 300 mm. In the process for seamless-pipe production, the round billet produced in the continuous casting step may be pierced/rolled with a piercer under conditions in which the ratio of the billet rotation speed to the billet outer-diameter draft is a value in a range suitable for the ratio of the gorge part diameter to the inlet diameter in the tilting rolls, thereby giving a seamless pipe reduced in defects in the inner surface. As a piercing plug may be used a plug of a suitable shape which is approximately cylindrical and has a spherical rolling part at the plug tip. Thus, Mannesmann fracture and circumferential-direction shear strain are significantly inhibited and no billet nipping failure occurs at all. This process for seamless-pipe production enables a seamless pipe having even higher inner-surface quality to be produced with exceedingly high productivity.

Inventors:
YAMANAKA AKIHIRO (JP)
ADACHI MANABU (JP)
YAMAKAWA TOMIO (JP)
NAKAIKE HIROTSUGU (JP)
SHIMODA KAZUHIRO (JP)
ANRAKU TOSHIRO (JP)
Application Number:
PCT/JP2006/306275
Publication Date:
October 04, 2007
Filing Date:
March 28, 2006
Export Citation:
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Assignee:
SUMITOMO METAL IND (JP)
YAMANAKA AKIHIRO (JP)
ADACHI MANABU (JP)
YAMAKAWA TOMIO (JP)
NAKAIKE HIROTSUGU (JP)
SHIMODA KAZUHIRO (JP)
ANRAKU TOSHIRO (JP)
International Classes:
B21B19/04; B22D11/00; B22D11/124; B22D27/04
Domestic Patent References:
WO2004103593A12004-12-02
WO2004052569A12004-06-24
Foreign References:
JPH08332556A1996-12-17
JP2002361304A2002-12-17
JP2006095565A2006-04-13
JPH071096A1995-01-06
JPH08332556A1996-12-17
JP2001062550A2001-03-13
JP2003117643A2003-04-23
JP2004330252A2004-11-25
JPH0313222A1991-01-22
JPS613605A1986-01-09
JP2000140911A2000-05-23
Other References:
See also references of EP 2008733A4
Attorney, Agent or Firm:
MORI, Michio (Amagasaki Building 17-23,Higashinaniwa-cho 5-chome, Amagasaki-sh, Hyogo 92, JP)
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