DOUBLE-WALLED PIPE WITH A GAP, AND MANUFACTURING METHOD THEREFOR

Title:

DOUBLE-WALLED PIPE WITH A GAP, AND MANUFACTURING METHOD THEREFOR

Document Type and Number:

WIPO Patent Application WO/2011/151971

Kind Code:

A1

Abstract:

In the disclosed method for manufacturing a double-walled pipe with a gap, a steel or alloy inner pipe is inserted into a ferrite steel outer pipe and then the double-walled pipe is cold-worked such that the outside diameter thereof decreases by 5% to 30%. The outer pipe contains at least 2% chromium, and a chromium-containing oxidized scale layer between 10 and 30 µm thick is generated on the inner surface thereof. The inner pipe contains at least 2% chromium and the outer surface thereof is cut or ground at least 0.1 mm, including a scale layer. The double-walled pipe may also be manufactured by inserting an inner pipe with an oxidized scale layer generated on the outer surface thereof into an outer pipe with the inner surface thereof cut or ground and then performing a similar cold-working process. A double-walled pipe manufactured by one of these methods has a uniform gap, conducts heat well, and is suitable for use as: a high-temperature heat-resistant pressure-resistant member for a power boiler, for use in the chemical industry, or for use in nuclear power; or a material for a steam generator tube in a conventional fast breeder reactor.

Inventors:

ISEDA ATSURO (JP)
NAKASHIMA TAKASHI (JP)
YOKOYAMA TETSUO (JP)
KAWAKAMI TADASHI (JP)
HANADA TAKUYA (JP)

Application Number:

PCT/JP2011/002524

Publication Date:

December 08, 2011

Filing Date:

May 02, 2011

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
ISEDA ATSURO (JP)
NAKASHIMA TAKASHI (JP)
YOKOYAMA TETSUO (JP)
KAWAKAMI TADASHI (JP)
HANADA TAKUYA (JP)

International Classes:

F16L9/02; B21C37/06; F28D7/10

Foreign References:

JPH03234314A	1991-10-18
JPS5841611A	1983-03-10
JPS63252614A	1988-10-19
JPH01193595A	1989-08-03

Other References: