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Title:
METHOD FOR PRODUCING SEAMLESS STEEL PIPE MADE OF HIGH Cr-HIGH Ni-BASED ALLOY STEEL
Document Type and Number:
Japanese Patent JP2008161906
Kind Code:
A
Abstract:

To provide a method for producing a seamless steel pipe made of a high Cr-high Ni-based alloy in which the generation of melted inside rash is prevented, and also, the service life of a plug can be improved.

When the stock to be rolled made of a high Cr-high Ni based alloy steel comprising, by mass, 20 to 30% Cr, 30 to 50% Ni and one or more selected from Mo and W by 1.5% in terms of Mo+0.5W is subjected to gradient piercing rolling, the stock to be rolled is heated under the conditions satisfying inequality; T1575-4.45Vf-104.7{-ln(th/ro)}, and is thereafter subjected to gradient piercing rolling under the conditions satisfying a roll gorge peripheral speed (m/sec) of 2.3 m/sec. In the inequality, T denotes a heating temperature (C); Vf denotes the roll peripheral speed (m/sec) in the roll gorge; ro denotes the radius (mm) of an inlet side stock billet; and th denotes the thickness (mm) of the pipe stock after the piercing.


Inventors:
HIRASE NAOYA
YAMAKAWA TOMIO
SHIMODA KAZUMUNE
Application Number:
JP2006353578A
Publication Date:
July 17, 2008
Filing Date:
December 28, 2006
Export Citation:
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Assignee:
SUMITOMO METAL IND
International Classes:
B21B19/04; C21D8/10; C22C38/00; C22C38/58
Domestic Patent References:
JPS6431505A1989-02-01
JPH11169914A1999-06-29
JP2000334505A2000-12-05
Foreign References:
WO2004108310A12004-12-16
Attorney, Agent or Firm:
Mikiji Sugioka
Terutada Hogami
Chihara