Title:
TITANIUM ALLOY SCREW FORMED BY ROLLING
Document Type and Number:
WIPO Patent Application WO/2010/082403
Kind Code:
A1
Abstract:
A titanium alloy screw produced from a titanium alloy screw material which has undergone plasma carburizing. The screw has a hardened groove bottom part and, hence, has a reduced coefficient of friction and improved fastening characteristics. The groove bottom part is prevented from cracking and is less apt to suffer crack propagation. A process for producing the screw is provided. A carburized layer is formed in a titanium alloy material so that the material has a maximum value of hardness at a depth of 1 µm or smaller from the surface, and the surface having the carburized layer is rolled to obtain a rolled titanium alloy screw. As a result of the rolling, a continuous flow of a metallic macrostructure in a region located deeper than about 1 µm from the surface of the carburized layer is formed in an ordered state along the shape of the groove bottom in a region extremely close to the groove bottom. Such work hardening based on the surface-part structural configuration brings about a sufficient increase in strength and causes no decrease in fatigue strength.
Inventors:
TANAKA KOICHI (JP)
TANAKA SHINICHI (JP)
TANAKA SHINICHI (JP)
Application Number:
PCT/JP2009/070088
Publication Date:
July 22, 2010
Filing Date:
November 24, 2009
Export Citation:
Assignee:
TANAKA LTD (JP)
TANAKA KOICHI (JP)
TANAKA SHINICHI (JP)
TANAKA KOICHI (JP)
TANAKA SHINICHI (JP)
International Classes:
C23C8/36; B21H3/02; F16B33/06; F16B35/00
Foreign References:
| JP2006307348A | 2006-11-09 | |||
| JPH11318520A | 1999-11-24 |
Attorney, Agent or Firm:
KAMADA Bunji et al. (JP)
Bunji Kamata (JP)
Bunji Kamata (JP)
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