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Title:
金属材の表面改質方法
Document Type and Number:
Japanese Patent JP5704524
Kind Code:
B2
Abstract:

To provide a metallic material which has a high hardness ultrafine crystal grain layer formed by severe plastic deformation etc., on a surface layer and further, a high hardness layer having a sufficient layer thickness and having higher hardness compared with a base material in the inner layer, and to provide a method for manufacturing the metallic material.

To the metallic material having the ultrafine crystal grain layer at least in a part of the surface layer, hardening by rapid short-time heating is applied, and a hardened structure is formed by leaving the ultrafine crystal grain layer. The ultrafine crystal grain layer can be formed by friction working, etc., using a working tool, and the ultrafine crystal grain layer in which sub-micron crystal grains of 100 nm to 1 μm and nano-crystal grains of <100 nm are present is formed. The hardening by rapid short-time heating can preferably be performed by induction hardening under the conditions of 0.3-1 s heating time and 750-950°C heating temperature. The extreme-surface layer is made to have strength and hardness which are equivalent to those of the induction-hardened product or higher than those of the induction-hardened product, and the base material is hardened too and has high hardness and the fatigue characteristics or the like can be improved.

COPYRIGHT: (C)2011,JPO&INPIT


Inventors:
Akira Terashima
Yoshitaka Misaka
Kazuhiro Kawasaki
Yoshikazu Todaka
Hironori Nagai
Yu Iguchi
Kaoru Kanna
Umemoto Minoru
Application Number:
JP2009262096A
Publication Date:
April 22, 2015
Filing Date:
November 17, 2009
Export Citation:
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Assignee:
Neturen Co., Ltd.
Toyohashi University of Technology
International Classes:
C21D1/10; C21D7/04
Domestic Patent References:
JP2007297651A
JP2010150576A
JP2007321198A
JP2006312202A
Foreign References:
WO2009041665A1
Attorney, Agent or Firm:
Yuki Yokoi