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Title:
PROCESS FOR PRODUCING SEAMLESS STEEL PIPE
Document Type and Number:
WIPO Patent Application WO/2005/123289
Kind Code:
A1
Abstract:
A process for producing a seamless steel pipe, in which the occurrence of inner surface flaw in the pipe can be reduced through lowering of the friction coefficient at draw rolling by means of a mandrel mill. At the draw rolling of hollow stock pipe, a lubricant composed mainly of at least one of graphite and mica is applied to the surface of mandrel bar, and further a lubricant composed mainly of a borate of monovalent alkali metal is fed onto the inner surface of hollow stock pipe, satisfying the following requirements (a) to (d). (a) The temperature of inner surface of stock pipe immediately after the completion of piercing is set for ≥ 1150&ring C, and the time from the completion of piercing to feeding of the lubricant composed mainly of a borate of monovalent alkali metal, or the time from the completion of descaling to feeding of the lubricant is set for 5 to 60 sec. (b) The temperature of inner surface of stock pipe during the feeding of the lubricant composed mainly of a borate of monovalent alkali metal is set for ≥ 1100&ring C. (c) The time from the feeding of the lubricant composed mainly of a borate of monovalent alkali metal to the initiation of draw rolling is set for ≥ 10 sec. (d) The temperature of inner surface of stock pipe immediately before the draw rolling is set so as to range from 1000&ring to 1170&ring C.

More Like This:
JPS5823512MANUFACTURING EQUIPMENT FOR SEAMLESS METAL PIPE
JPH05237514METHOD AND DEVICE FOR ROLLING BY MANDREL MILL
Inventors:
IIDA SUMIO (JP)
NAKANISHI TETSUYA (JP)
Application Number:
PCT/JP2005/010943
Publication Date:
December 29, 2005
Filing Date:
June 15, 2005
Export Citation:
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Assignee:
SUMITOMO METAL IND (JP)
IIDA SUMIO (JP)
NAKANISHI TETSUYA (JP)
International Classes:
B21B17/02; B21B17/04; B21B25/04; B21B19/04; B21B45/04; (IPC1-7): B21B17/02; B21B25/04
Foreign References:
JP2000042609A2000-02-15
JP2000246312A2000-09-12
JP2004223528A2004-08-12
Other References:
See also references of EP 1775038A4
Attorney, Agent or Firm:
Honoue, Terutada (17-23 Higashinaniwa-cho 5-chome, Amagasaki-sh, Hyogo 92, JP)
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