US 12,000,021 B2
α+β type titanium alloy wire and manufacturing method of α+β type titanium alloy wire
Ryotaro Miyoshi, Tokyo (JP); Tomonori Kunieda, Tokyo (JP); Kazuhiro Takahashi, Tokyo (JP); Tatsuo Yamazaki, Tokyo (JP); and Akira Kawakami, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/281,029
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Oct. 7, 2019, PCT No. PCT/JP2019/039473
§ 371(c)(1), (2) Date Mar. 29, 2021,
PCT Pub. No. WO2020/075667, PCT Pub. Date Apr. 16, 2020.
Claims priority of application No. 2018-191179 (JP), filed on Oct. 9, 2018; and application No. 2018-191180 (JP), filed on Oct. 9, 2018.
Prior Publication US 2021/0348252 A1, Nov. 11, 2021
Int. Cl. C22C 14/00 (2006.01); C21D 8/06 (2006.01); C21D 9/52 (2006.01)
CPC C22C 14/00 (2013.01) [C21D 8/06 (2013.01); C21D 9/525 (2013.01)] 6 Claims
OG exemplary drawing
 
1. An α+β type titanium alloy wire, containing: in mass %,
Al: 4.50 to 6.75%;
Si: 0 to 0.50%;
C: 0.080% or less;
N: 0.050% or less;
H: 0.016% or less;
O: 0.25% or less;
Mo: 0 to 5.5%;
V: 0 to 4.50%;
Nb: 0 to 3.0%;
Fe: 0 to 2.10%;
Cr: 0 to less than 0.25%;
Ni: 0 to less than 0.15%;
Mn: 0 to less than 0.25%; and
the balance being Ti and impurities,
the contents of Al, Mo, V, Nb, Fe, Cr, Ni, and Mn satisfying the following equation (1), wherein:
a diameter of the wire of 15 mm or less:
an average aspect ratio of an α crystal grain is 1.0 to 3.0;
a maximum crystal grain diameter of the α crystal grain is 30.0 μm or less;
an average crystal grain diameter of the α crystal grain is 1.0 μm to 15.0 μm; and
an area ratio of the α crystal grain, out of the α crystal grains in a cross section orthogonal to a long axis direction of the wire, regarding which an inclination angle in a c-axis direction of a hexagonal close packing crystal that forms the α crystal grain relative to the long axis direction is within a range of 15° to 40°, is 5.0% or less,
−4.0≤[Mo]+0.67 [V]+0.28 [Nb]+2.9 [Fe]+1.6 [Cr]+1.1 [Ni]+1.6 [Mn]−[Al]≤2.0   (1)
in the above equation (1), notation of [symbol of element] represents a content (mass %) of a corresponding symbol of element, and a symbol of element which is not contained, is substituted by 0.