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.
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Inventors:
YAMANAKA AKIHIRO (JP)
ADACHI MANABU (JP)
YAMAKAWA TOMIO (JP)
NAKAIKE HIROTSUGU (JP)
SHIMODA KAZUHIRO (JP)
ANRAKU TOSHIRO (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:
Assignee:
SUMITOMO METAL IND (JP)
YAMANAKA AKIHIRO (JP)
ADACHI MANABU (JP)
YAMAKAWA TOMIO (JP)
NAKAIKE HIROTSUGU (JP)
SHIMODA KAZUHIRO (JP)
ANRAKU TOSHIRO (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:
WO2004103593A1 | 2004-12-02 | |||
WO2004052569A1 | 2004-06-24 |
Foreign References:
JPH08332556A | 1996-12-17 | |||
JP2002361304A | 2002-12-17 | |||
JP2006095565A | 2006-04-13 | |||
JPH071096A | 1995-01-06 | |||
JPH08332556A | 1996-12-17 | |||
JP2001062550A | 2001-03-13 | |||
JP2003117643A | 2003-04-23 | |||
JP2004330252A | 2004-11-25 | |||
JPH0313222A | 1991-01-22 | |||
JPS613605A | 1986-01-09 | |||
JP2000140911A | 2000-05-23 |
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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