METHOD OF GAS CARBURIZING - KOYO THERMO SYS CO LTD

Title:

METHOD OF GAS CARBURIZING

Document Type and Number:

WIPO Patent Application WO/2003/104516

Kind Code:

A1

Abstract:

A method of gas carburizing wherein the carburizing is performed at a temperature that is not higher than a peritectic point inducing transformation from &dgr -iron and liquid phase to &gammad -iron but not lower than a eutectic point inducing transformation from liquid phase to &gammad -iron and cementite. In particular, the method comprises a step of determining in advance such critical carburizing conditions that the surface layer of steel-made treatment object sample in carburizing atmosphere is austenitized without fusing and a step of gas carburizing the treatment object under carburizing conditions set so as not to disagree with the critical carburizing conditions at a carburizing temperature that is not higher than the peritectic point but not lower than the eutectic point. The critical carburizing conditions involve the upper limit value of carburizing gas partial pressure under which the sample surface layer is austenitized without fusing.

Inventors:

TACHISATO SHOWA (JP)

Application Number:

PCT/JP2003/005422

Publication Date:

December 18, 2003

Filing Date:

April 28, 2003

Export Citation:

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Assignee:

KOYO THERMO SYS CO LTD (JP)
TACHISATO SHOWA (JP)

International Classes:

C23C8/22; (IPC1-7): C23C8/22

Foreign References:

JPH11200009A	1999-07-27
JPH0959756A	1997-03-04
JP2001081543A	2001-03-27
JPH06192815A	1994-07-12
JP2000129418A	2000-05-09
JPH10121128A	1998-05-12

Other References: