FIELD OF THE INVENTION

This invention in general relates to the field of metallurgy. More particularly, this invention relates to the manufacture of a Titanium based alloy which finds its use extensively in aerospace applications. More specifically, this invention relates to the manufacture of wires with diameters lesser than 15 millimetres of the Titanium based alloy using effective and economical process.

BACKGROUND OF THE INVENTION

Titan 31 is popularly known as TU6A1-4V Titanium alloy throughout the world. It is extensively used in aerospace industry because it exhibits the property of high specific strength. It is a two phase alpha-beta type alloy and it is available in two variants. The first one is the normal grade with oxygen upto 2000 ppm which finds its application upto temperature levels 300°C. The second one which is Extra low interstitial (ELI) grade with oxygen upto 1300 ppm which is known for exhibiting the property of toughness can be used in applications as low as -196 ° C.

But one of the major problems faced in the manufacturing process of components involved using this alloy is the poor cold workability. It is also prohibitively costly to get components of the alloy using normal cold drawing process with intermittent Vacuum Annealing process.

Also, another difficulty faced is to achieve wires/rods of the alloy using conventional hot rolling process especially with diameters lesser than 15 millimetres.

Hence, there arises a need for TU6A1-4V Titanium alloy wires/rods of lesser diameters (less than 15 millimeters) and a method of manufacture of the same with good workability at elevated temperatures.

SUMMARY OF THE INVENTION

Accordingly, this invention provides a titanium based alloy wire/rods for welding application comprising titanium, aluminium and vanadium, wherein the diameter of the titan based alloy wire/rods is less than 15 millimeters.

Further, this invention provides a method of manufacturing Titanium alloy wires/rods. The method comprises the steps of combination of hot swaging and hot drawing process followed by limited air annealing.

The material of the wires for manufacturing of the Titanium alloy is achieved by mechanical alloying of the base titanium metal with aluminium, and vanadium elements in a double cone mixer, followed by compacting using Hydraulic means.

The compacts of the titanium alloy are further subjected to plasma welding followed by double vacuum arc remelting to obtain ingots and further the ingots are skin turned.

The ingots of the titanium alloy are further subjected to hot forging to achieve forged bars of square cross section in the range of 100 mm, and further hot rolled by bar and wire rod milling to achieve 15 millimetre diameter bars, which are again subjected to swaging to get the diameter reduced further in the range of 1 - 5 millimetres (mm).

The wires of the titanium alloy are further subjected to hot drawing action to achieve coils whose diameter are in the range of 1.8 millimetres (mm) and further subjected to air annealing at 700° C.

Finally the wires of the titanium alloy are pickled and cold drawn.

It is an object of this invention to provide Ti-6A1-4V Titanium alloy wires of lesser diameters (less than 15 millimeters)

It is yet another object of this invention to achieve lesser diameter wires using Ti-6A1-4V Titanium alloy by advantageously utilizing the good hot workability process of the alloy.

Further, it is yet another object of the invention to provide a process of production of thin diameter Ti-6A1-4V Titanium alloy wires which is economical and at the same time the quality of the Titanium alloy wires achieved is high with good tolerance levels.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention will now be explained with reference to the accompanying description. However, it will be apparent to a person of ordinary skill in the art that the disclosed embodiments are merely exemplary and that the present invention may be embodied in various forms. The following description is not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However, in certain instances, well-known or conventional details may not be described in order to maintain clarity.

Titan 31, the Titanium based alloy (Ti-6A1-4V) is found to exist in two allotropic forms at different temperatures. Based on its Lattice arrangement, they are a) Hexagonally close packed (HCP) structure which is when it is subjected to temperatures of 882° C. But above 882° C, temperature, it is found to be existing in Body Centred Cubic structure ( BCC) which is found to be possessing desirable properties such as good workability.

The Ti-6A1-4V alloy is made through double vacuum arc remelting process to get sound ingots. The Ingots are further skin turned to remove surface defects and heated in a furnace to make them ready for hot forging operation. These hot ingots are forged using 1500 T press to achieve forged bars with square cross section. Forged bars are further hot rolled to 15 mm diameter rods in a hot rolling mill. These rods are further hot swaged and hot drawn in a sequence to achieve desired final diameter. Adherence to the step wise and adequate quality checks play a critical role in achieving the flaw less end product.

The following operations explain in detail the step wise operations involved in the manufacture of thin wires (less than 15 millimetres) of Ti-6A1-4V alloy material, using the innovative process of combination of hot swaging and hot drawing with limited air annealing to achieve thinner diameter.

The material of the wires of the Titanium alloy is achieved by mechanical alloying of the base titanium metal with other elements in a double cone mixer, which is followed by compacting using Hydraulic press.

Further, the material of the wires of the titanium alloy is subjected to plasma welding followed by double vacuum arc remelting to obtain ingots which are skin turned further.

Then, the skin turned material of the wires of the titanium alloy is subjected to hot forging to achieve forged bars of square cross section in the range of 100 mm, and further hot rolling by bar and wire rod milling yields 15 millimetre diameter bars, which are again subjected to swaging to get the diameter reduced further in the range of 5 millimetres (mm).

The wires of the titanium alloy thus achieved subjected to hot drawing action to achieve coils whose diameter are in the range of 1.8 millimetres (mm) and are further subjected to air annealing at 700° C and are finally pickled and cold drawn to achieve the wires with diameters upto 1.6 millimeters (mm).

CLAIMS

What is claimed is:

1. A Titanium based alloy wire/rods for welding application comprising titanium, aluminium and vanadium, wherein the diameter of the titan based alloy wire/rods is less than 15 millimeters.

2. A method of manufacturing Titanium alloy wires/rods as claimed in claim 1, wherein the method comprises the steps of combination of hot swaging and hot drawing process followed by limited air annealing.

3. A method of manufacturing Titanium alloy wires/rods as claimed in claim 2, wherein the material of the wires for manufacturing of the Titanium alloy is achieved by mechanical alloying of the base titanium metal with aluminium, and vanadium elements in a double cone mixer, followed by compacting using Hydraulic means.

4. A method of manufacturing Titanium alloy wires/rods as claimed in claim 3, wherein the wires of the titanium alloy are further subjected to plasma welding followed by double vacuum arc remelting to obtain ingots and further the ingots are skin turned.

5. A method of manufacturing Titanium alloy wires/rods as claimed in claim 4, wherein the wires of the titanium alloy are subjected to hot forging to achieve forged bars of square cross section in the range of 100 mm, and further hot rolled by bar and wire rod milling to achieve 15 millimetre diameter bars, which are again subjected to swaging to get the diameter reduced further in the range of 5 millimetres (mm).

6. A method of manufacturing Titanium alloy wires/rods as claimed in claim 5, wherein the wires of the titanium alloy are subjected to hot drawing action to achieve coils whose diameter are in the range of 1.8 millimetres (mm) and further subjected to air annealing at 700° C.

7. A method of manufacturing Titanium alloy wires/rods as claimed in claim 6, wherein the wires of the titanium alloy are finally pickled and cold drawn.