NITRIDING PROCESS FOR MARAGING STEEL

Title:

NITRIDING PROCESS FOR MARAGING STEEL

Document Type and Number:

WIPO Patent Application WO/2011/077945

Kind Code:

A1

Abstract:

Provided is a nitriding process for maraging steel, by which the compressive residual stress of maraging steel can be enhanced. On the surface of a work of maraging steel, part of the titanium solid-soluted in the work is oxidized with oxygen to form titanium oxide (TiO2) on the surface of the work positively, whereby the concentration of titanium oxide on the surface is enhanced (solution treatment step); since titanium present in the form of an oxide does not react with nitrogen in a nitriding step, the resulting work is subjected to sufficient reduction pretreatment prior to a nitriding step to conduct the removal of oxygen; thus, the surface concentration of titanium present in an active state is enhanced; and then the work thus pretreated is subjected to nitriding, whereby the reduced titanium and the solid-soluted titanium are bonded to nitrogen to form titanium nitride (TiN). In this nitriding step, the titanium present in the work is in an active state and therefore can be easily nitrided. Further, the surface concentration of titanium present in an active state is high, so that much nitrogen can penetrate into the work.

Inventors:

TAKAGAKI MASASHI (JP)
MASE HIROAKI (JP)
NARITA NAOKI (JP)

Application Number:

PCT/JP2010/071924

Publication Date:

June 30, 2011

Filing Date:

December 07, 2010

Export Citation:

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Assignee:

HONDA MOTOR CO LTD (JP)
TAKAGAKI MASASHI (JP)
MASE HIROAKI (JP)
NARITA NAOKI (JP)

International Classes:

C23C8/26; C21D1/06; C22C38/00; C23C8/02; C21D9/40; C22C38/52

Foreign References:

JP2000087214A	2000-03-28
JP2006124757A	2006-05-18
JP2002167652A	2002-06-11
JPH07188896A	1995-07-25
JP2004162134A	2004-06-10

Other References: