STEEL MEMBERS, METHOD FOR HEAT TREATMENT OF THE SAME, AND PROCESS FOR PRODUCTION THEREOF

Title:

STEEL MEMBERS, METHOD FOR HEAT TREATMENT OF THE SAME, AND PROCESS FOR PRODUCTION THEREOF

Document Type and Number:

WIPO Patent Application WO/2007/034911

Kind Code:

A1

Abstract:

A process which comprises the vacuum carburizing step (a1) of carburizing a steel member in a carburizing gas under a reduced pressure, the vacuum cooling step (a2) of cooling the resulting carburized steel member in a cooling gas in such a state that the pressure of the cooling gas pressure is lower than the atmospheric pressure, and the hardening step (a3) of hardening a desired part of the cooled steel member by using high-density energy. It is preferable that the vacuum cooling step be conducted in such a state that the pressure of the cooling gas is lower than the atmospheric pressure and while stirring the cooling gas. The vacuum cooling step is preferably conducted from the beginning of structure transformation of the member by cooling until the completion of all structure transformations thereof. The pressure of the cooling gas in the vacuum cooling step is preferably 0.1 to 0.65bar.

Inventors:

TANIGUCHI TAKAO (JP)
SHIRAI HISAO (JP)
OHBAYASHI KOJI (JP)
OKADA KAZUAKI (JP)
KANISAWA HIDEO (JP)
KOZAWA SHUJI (JP)

Application Number:

PCT/JP2006/318839

Publication Date:

March 29, 2007

Filing Date:

September 22, 2006

Export Citation:

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Assignee:

AISIN AW CO (JP)
TANIGUCHI TAKAO (JP)
SHIRAI HISAO (JP)
OHBAYASHI KOJI (JP)
OKADA KAZUAKI (JP)
KANISAWA HIDEO (JP)
KOZAWA SHUJI (JP)

International Classes:

C21D9/32; C21D1/00; C21D1/06; C21D1/10; C21D9/00; C22C38/00; C22C38/38; C23C8/22

Domestic Patent References:

WO1997000374A1

1997-01-03

Foreign References:

JP2002363726A	2002-12-18
JPS63149313A	1988-06-22
JP2003056669A	2003-02-26
JP2004124127A	2004-04-22
JPH11131133A	1999-05-18
JPH05148535A	1993-06-15
JPH08311607A	1996-11-26

Other References: