METAL TUBE FOR USE IN CARBURIZING GAS ATMOSPHERE

Title:

METAL TUBE FOR USE IN CARBURIZING GAS ATMOSPHERE

Document Type and Number:

WIPO Patent Application WO/2005/078148

Kind Code:

A1

Abstract:

A metal tube for use in a carburizing gas atmosphere, which comprises a Cu-rich layer having a Cu concentration of 0.1 atomic % or more and a thickness of 0.3 nm or more in the surface portion thereof, and comprises a base material having an alloy composition, in mass %, wherein Cr: 15 to 35 %, Ni: 30 to 75 %, Al: 0.001 to 10 %, and Cu: 0.01 to 10 %. The metal tube may further comprise an oxide scale layer containing Cr as a main component and having a Cr content of 50 % or more or an oxide scale layer containing Cr and Al as main components and having a total content of (Cr + Al) of 50 % or more, on the outside of the above Cu-rich layer, and may still further comprise a second oxide scale layer containing Si as a main component and having a Si content of 50 % or more, between the above oxide scale layer and the above Cu-rich layer. The above metal tube has a function of shielding the base material from a carburizing gas, and is excellent in the resistance to metal dusting, to carburizing and to coking.

Inventors:

NISHIYAMA YOSHITAKA (JP)
OTSUKA NOBUO (JP)
KUDO TAKEO (JP)

Application Number:

PCT/JP2005/000892

Publication Date:

August 25, 2005

Filing Date:

January 25, 2005

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
NISHIYAMA YOSHITAKA (JP)
OTSUKA NOBUO (JP)
KUDO TAKEO (JP)

International Classes:

C21D1/26; C21D8/10; C21D9/08; C22C19/05; C22C38/00; C22C38/16; C22C38/58; C23C28/00; C23F15/00; (IPC1-7): C22C38/00; C21D9/08; C22C19/05; C22C38/16; C22C38/58; C23F15/00

Foreign References:

JP2003073763A	2003-03-12
JPH0729129B2	1995-04-05
JP3355510B2	2002-12-09
JPH11302796A	1999-11-02

Other References: