PROCESS FOR PRODUCING SEAMLESS STEEL PIPE

Title:

PROCESS FOR PRODUCING SEAMLESS STEEL PIPE

Document Type and Number:

WIPO Patent Application WO/2005/115650

Kind Code:

A1

Abstract:

A round billet comprising 10.50 to 14.00% by mass of Cr and satisfying a value of not more than 9.0% as determined by a formula [Cr + 4Si - (22C + 0.5Mn + 1.5Ni + 30N)] wherein the symbol of element represents the content (% by mass) of each constituent element in the steel is heated under conditions of a soaking temperature of 1100 to 1250°C and an in-furnace time (min) of not less than “0.5 × diameter of round billet (mm)”. Thereafter, piercing and rolling are carried out under conditions of a piercer piercing efficiency of not less than 50%, a value of not more than 8.0 as specified by “&lcub (diameter of round billet - roll spacing at foremost end of plug)/diameter of round billet&rcub × 100”, and a plug shape of 0.06 to 0.17 as defined by &lcub radius of foremost end of plug (mm)/diameter of round billet (mm)&rcub ”. The high Cr seamless steel pipe thus obtained has no significant internal flaw, that is, has excellent internal properties.

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JP3855300	PRODUCTION OF SEAMLESS STEEL PIPE AND PRODUCING EQUIPMENT

Inventors:

NAKAIKE KOUJI (JP)
NAKANISHI TETSUYA (JP)
NAKATA JUNJI (JP)

Application Number:

PCT/JP2005/009622

Publication Date:

December 08, 2005

Filing Date:

May 26, 2005

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
NAKAIKE KOUJI (JP)
NAKANISHI TETSUYA (JP)
NAKATA JUNJI (JP)

International Classes:

B21B19/04; B21B3/02; B21B17/14; B21B19/06; B21B23/00; (IPC1-7): B21B19/04

Foreign References:

JP2004043935A	2004-02-12
JP2002361304A	2002-12-17
JPH105820A	1998-01-13
JP2003001305A	2003-01-07

Other References: