U.S. patent application number 10/496493 was filed with the patent office on 2006-02-23 for metastable beta-titanium alloy.
Invention is credited to Igor Vasilievich Levin, Denis Valeryervich Sosnovsky, Vladislav Valentinovich Tetyukhin.
Application Number | 20060039819 10/496493 |
Document ID | / |
Family ID | 20254397 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060039819 |
Kind Code |
A1 |
Tetyukhin; Vladislav Valentinovich
; et al. |
February 23, 2006 |
Metastable beta-titanium alloy
Abstract
Metastable .beta.-titanium alloy contains, in mass %: from 1.5
to 3.5 aluminum; from 4.5 to 8.0 molybdenum; from 1.0 to 3.5
vanadium; from 1.5 to 3.8 iron; titanium balance. This alloy
combines high strength and ductility. This allows to use it for
production of a wide range of critical parts including fastener
components and different coil springs (e.g. in automobile
industry).
Inventors: |
Tetyukhin; Vladislav
Valentinovich; (Moscow, RU) ; Levin; Igor
Vasilievich; (Sverdlovskaya, RU) ; Sosnovsky; Denis
Valeryervich; (Sverdlovskaya, RU) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Family ID: |
20254397 |
Appl. No.: |
10/496493 |
Filed: |
November 18, 2002 |
PCT Filed: |
November 18, 2002 |
PCT NO: |
PCT/RU02/00502 |
371 Date: |
July 21, 2005 |
Current U.S.
Class: |
420/420 |
Current CPC
Class: |
C22C 14/00 20130101 |
Class at
Publication: |
420/420 |
International
Class: |
C22C 14/00 20060101
C22C014/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2001 |
RU |
2001131383 |
Claims
1. A metastable .beta.-titanium alloy containing aluminum,
molybdenum, and iron, and vanadium, consisting essentially of (mass
%): TABLE-US-00004 Aluminum 1.5-3.5 Molybdenum 4.5-8.0 Vanadium
1.0-3.5 Iron 1.5-3.8 Titanium balance.
2. The alloy of claim 1 exhibiting a minimum percent reduction of
area of 7.3 in a solution-treated condition.
3. The alloy of claim 1 exhibiting a yield strength of at least
1020 MPa.
4. A metastable .beta.-titanium-base alloy consisting of (mass %):
TABLE-US-00005 Aluminum 1.5-3.5 Molybdenum 4.5-8.0 Vanadium 1.0-3.5
Iron 1.5-3.8
5. The alloy of claim 4 exhibiting a minimum percentage reduction
of area of 7.3 in a solution-treated condition.
6. The alloy of claim 4 exhibiting a yield strength of at least
1020 MPa.
7. The alloy of claim 1 wherein the molybdenum is added as
ferromolybdenum with 55-75% of molybdenum and a balance of
iron.
8. The alloy of claim 1 wherein the vanadium is added as
ferrovanadium with 65-80% of vanadium and a balance of iron.
9. The alloy of claim 1 wherein the vanadium is added as a
Ti--Al--V system scrap.
10. The alloy of claim 4 wherein the molybdenum is added as
ferromolybdenum with 55-75% of molybdenum and a balance of
iron.
11. The alloy of claim 4 wherein the vanadium is added as
ferrovanadium with 65-80% of vanadium and a balance of iron.
12. The alloy of claim 4 wherein the vanadium is added as a
Ti--Al--V system scrap.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the non-ferrous metallurgy, and
more particularly to the development of new titanium-base alloys
combining high strength and ductility properties using relatively
low-cost alloying elements. The alloys of this invention can be
applied in a wide range of products especially fasteners and
different coil springs.
PRIOR STATE OF ART
[0002] One of the known titanium alloys is the alloy containing
(mass %): 2-6 Al; 6-9 Mo; 1-3 V; 0.5-2 Cr; 0-1.5 Fe; Ti balance.
Ref: USSR Inventor's Certificate No. 180351, Class C22C 14/00,
1966.
[0003] However, this alloy has insufficient ductility due to the
high content of Al and the presence of Cr. Besides this alloy is
rather expensive.
[0004] The other known titanium alloy contains (mass %): 4-6.3 Al;
4.5-5.9 V; 4.5-5.9 Mo; 2.0-3.6 Cr; 0.2-0.5 Fe; Ti balance. Ref: RF
Patent No. 2169204, Class C22C 14/00, published 2001.
[0005] The said alloy as-heat treated has high strength properties
in heavy section forgings, but its ductility is insufficient and so
the alloy cannot be used for production of such parts as coil
springs.
[0006] The most close to the claimed invention is the metastable
.beta.-titanium alloy containing (mass %): 4-5 Fe; 4-7 Mo; 1-2 Al;
O.sub.2 up to 0.25; Ti balance. Ref: U.S. Pat. No. 5,294,267, Class
C22C 14/00, published 1994. This alloy will be the prototype.
[0007] This alloy has high machinability, demands relatively low
costs and is widely used for production of coil cylindrical springs
in automotive industry.
[0008] However, the said alloy has low ductility properties,
especially elongation, which reduces the application of this alloy
and is of importance during manufacture of some types of coil
springs and fastener components.
DISCLOSURE OF THE INVENTION
[0009] The object of this invention is to provide a titanium alloy
with combination of high ductility and strength properties in
as-heat treated condition, which can be produced using low cost
alloying elements.
[0010] In accordance with the invention this is achieved by
addition of vanadium to the metastable .beta.-titanium alloy
containing aluminum, molybdenum and iron at the following content
of components (mass %): TABLE-US-00001 Aluminum 1.5-3.5 Molybdenum
4.5-8.0 Vanadium 1.0-3.5 Iron 1.6-3.8 Titanium balance
[0011] The addition of 1.0-3.5% vanadium increases the alloy
ductility as required.
[0012] To achieve high strength properties this alloy has higher
content of aluminum than the prototype. The content of aluminum of
less than 3.5% does not significantly influence on the alloy
ductility. The contents of aluminum greater than 3.5% and iron
greater than 3.8% increases the .alpha.-phase quantity, causes
hardening and reduces ductility lower than desired. The lower
content of iron (<4%) than in the prototype ensures greater
phase stability during thermal cycles (deformation and heat
treatment); The desired strength properties cannot be achieved with
aluminum below 1.5%. The content of molybdenum below 4.5% and iron
below 1.6% reduces .beta.-phase quantity and does not allow to
achieve high strength of the as-heat treated alloy.
[0013] The increase in the content of such .beta.-stabilizers as
molybdenum and vanadium exceeding the specified limits reduces the
alloy stability in hardened and aged conditions and increases the
grain size during heat treatment, which significantly reduces the
alloy ductility (.beta.<4%; .PSI.<7%).
[0014] Molybdenum is added as ferromolybdenum with 55-75% of
molybdenum and iron balance.
[0015] Vanadium is added as ferrovanadium with 65-85% of vanadium
and iron balance or Ti--Al--V system scrap.
EMBODIMENTS OF THE INVENTION
[0016] To study the properties of the alloy, ingots with the
composition shown in Table 1 were melted in a vacuum arc furnace
and 20 mm diameter bars were made from these ingots. The bars were
heat treated under the following conditions: heating to temperature
of 30.degree. C. below beta transus temperature, water cooling,
heating to 480.degree. C. for 8 hours, air cooling. Then tensile
specimens were tested according to ASTM E 8.
[0017] Mechanical properties of the produced bars from the
evaluated alloys are shown in Table 2. TABLE-US-00002 TABLE 1
Element Content (wt %) Example Al Mo V Fe Ti 1. 2.5 5.5 2.0 2.5
balance 2. 3.0 6.5 3.0 3.5 balance 3. 3.5 8.0 3.5 3.8 balance
[0018] TABLE-US-00003 TABLE 2 Mechanical Properties Ultimate Yield
Reduction Strength, Strength, Elongation of Area Example
.sigma..sub.B, MPa .sigma..sub.0.2, MPa .delta., % .psi., % 1. 1250
1190 20.2 46.4 2. 1440 1390 6.1 10.2 3. 1520 1480 4.9 7.3
Commercial Practicability
[0019] The claimed metastable .beta.-titanium alloy as compared to
the known alloys has the specified optimal combination of beta and
alpha stabilizing alloying elements, which ensure high strength and
ductility of the as-heat treated alloy. It is low cost and can be
used for production of a wide range of critical parts, especially
fastener components and different coil springs.
* * * * *