β-type titanium alloy

Patent metadata

Field	Value
Publication number	US-9822431-B2
Application number	US-201213358483-A
Country	US
Kind code	B2
Filing date	Jan 25, 2012
Priority date	Oct 26, 2006
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

The present invention provides a β-type titanium alloy that includes, by mass %, when Al: 2 to 5%, 1) Fe: 2 to 4%, Cr: 6.2 to 11%, and V: 4 to 10%, 2) Fe: 2 to 4%, Cr: 5 to 11%, and Mo: 4 to 10%, or 3) Fe: 2 to 4%, Cr: 5.5 to 11%, and Mo+V (total of Mo and V): 4 to 10% in range, and a balance of substantially Ti. These include Zr added in amounts of 1 to 4 mass %. Furthermore, by making the oxygen equivalent Q 0.15 to 0.30 or leaving the alloy in the work hardened state or by applying both, the tensile strength before aging heat treatment can be further increased.

First claim

The invention claimed is:

1. A β-type titanium alloy, which will consist of an α phase and a β phase after aging, containing, by mass %, Al: 2 to 5%, Fe: 2.6 to 4%, Cr: 6.2 to 9%, and V: 4 to 10% in ranges and having a balance of Ti and unavoidable impurities,
wherein:
when a Vicker's hardness is randomly measured at six points in each of three L-cross-sections, a difference between a maximum value and a minimum value thereof is in a range from 10 to 20,
a tensile strength of the β-type titanium alloy before aging is 920 MPa or more, and
the β-type titanium alloy does not contain Sn,
the α phase is substantially uniformly precipitated after solution treatment, drawing and aging.

2. The β-type titanium alloy as set forth in claim 1 characterized in that an oxygen equivalent Q of formula [1] is 0.15 to 0.30:
Oxygen equivalent Q=[O]+2.77[N]  formula [1]

where, [O] is O (oxygen) content (mass %) and [N] is N content (mass %).

3. A worked product obtained by work hardening the β-type titanium alloy as set forth in claim 1 .

4. A β-type titanium alloy, which will consist of an α phase and a p phase after aging, containing, by mass %, Al: 2 to 5%, Fe: 2.6 to 4%, Cr: 5.5 to 9%, and Mo+V (total of Mo and V): 4 to 10% by Mo: 0.5% or more and V: 0.5% or more in ranges and having a balance of Ti and unavoidable impurities,
wherein:
when a Vicker's hardness is randomly measured at six points in each of three L-cross-sections, a difference between a maximum value and a minimum value thereof is in a range from 10 to 20,
a tensile strength of the β-type titanium alloy before aging is 920 MPa or more, and
the β-type titanium alloy does not contain Sn,
the α phase is substantially uniformly precipitated after solution treatment drawing and aging.

Assignees

• Takahashi Kazuhiro
• Fujii Hideki
• Mori Kenichi
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Takahashi Kazuhiro
• Fujii Hideki
• Mori Kenichi

Classifications

• C22F1/18

  High-melting or refractory metals or alloys based thereon · CPC title

• C22F1/00

  Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24) · CPC title

• C22C14/00 Primary

  Alloys based on titanium · CPC title