JPS62192552A - High-strength ti alloy excellent in cold workability - Google Patents

Abstract

PURPOSE:To improve strength, cold workability, and hardness after cold working of a Ti alloy, by incorporating as principal components specific amounts of Al, V, and Nb to Ti and by controlling oxygen content. CONSTITUTION:An alloy has a composition consisting of, by weight, 0.8-1.5% Al, 1-2% V, 1-2% Nb, 0.2-0.3% oxygen, and the balance Ti with inevitable impurities and further containing, if necessary, either or both of 0.1-0.5% of one or more elements among Zr, Sn, Fe, Cu, and Cr and 0.1-1% Mo. A Ti alloy with this composition has high strength as compared with pure Ti and is capable of cold working under severe conditions and, moreover, it has high hardness even after working. This alloy is suitable for use in manufacture of spectacle frames, aircraft parts, automobile parts, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has a high strength electric current and an excellent cold hammering method, and furthermore, (two cold hammering blades (-accompanied hardness increase) (= high hardness change due to This is a Ti alloy suitable for manufacturing eyeglass frames, aircraft parts, automobile parts, etc., which require special orders.

[Conventional technology]

Conventional 1 For example, Ti-3%Al-2.5%M alloy and T
α+β type Ti alloys such as i-6%M-4%M alloys, and α+β type Ti alloys such as (2Ti-2.5%Cu alloys) indicates the weight of the duck]
has an extremely high specific strength (strong 1f) among practical metal materials.
/ specific gravity), it has been used to manufacture aircraft parts, etc., but in recent years, it has been used for manufacturing aircraft parts etc.
Also, due to its high electrical power, its usage in general industrial applications is rapidly increasing.

One example is Ti? There is a J glasses frame, which takes advantage of the special characteristics of Ti, which has a high electric current with a 1@ content and has good corrosion resistance.

In this case, metal eyeglass frames are generally produced through relatively severe cold working compared to other metal products, and usually the processing rate is near 0 in the manufacturing process.
In addition to being cold-worked over %a, the hardness of nickel silver and Ti-clad materials, which are the mainstream materials for current metal eyeglass frames, is about 270 Vickers hardness (My) after cold working. It has become.

On the other hand, in recent years, even in the above-mentioned Ti eyeglass frames, there has been a strong demand for further reduction in thickness due to thinning.

[Problem that the invention seeks to solve]

However, when the above-mentioned pure Ti eyeglass frames are made thin, there is a problem that not only does the strong electric current become insufficient, but the hardness after cold working does not reach the Hv: 270 C of nickel silver or Ti clad materials. It's thin (I can't do it. So pure T)
iyoI] Attempts have been made to use the various Ti alloys mentioned above that have high and high strength in the production of eyeglass frames, but the above α+
β-type Ti alloys and α-10 intermetallic precipitate type Ti alloys have sufficient hardness and hardness, but cold workability is extremely poor, and cold scraping occurs. The current problem is that it cannot be put to practical use.

[Tth means to solve the gap]

Therefore, from the above-mentioned viewpoint, the inventors of the present invention conducted research to develop a Ti alloy particularly suitable for manufacturing lightweight eyeglass frames. s~t, s%, V: 1~2%, Nb: 1~2%, acid! :0.2 to 0.3%, and further contains one or more of Zr*SnrFe+CUT and C20.1 to 0.5% as necessary. , Mo: 0.1 to 1%, or both, and the remaining I] has a composition consisting of Ti and unavoidable impurities. Possible without annealing C:, hardness after cold (2) 1 Hv: 270
(above and more) and has high strength. Therefore, when used in the manufacture of eyeglass frames, not only is it possible to reduce the thickness due to C: but also it is possible to use cold forging as a manufacturing process. We have obtained knowledge that it is lightweight [possible] and exhibits excellent performance even when used in the manufacture of aircraft parts and pilot car parts that require cold rolling. .

This invention has been made based on the above findings (-), and the reasons why the component compositions are limited as described above (-) will be explained below.

(al A11 M component C: is the same as the Zr component (-1 matrix (2 solid solution) and has the effect of increasing the strong electric current and hardness, but its content is 0. If the content is less than 8%, it will not be possible to achieve a hardness of Hv: 270 or higher after cold rolling, while if the content exceeds 1.5%, cracking will occur during cold rolling with a working rate of 70%. Therefore, the content was set at 0.8 to 1.5%.

fbl V Component (2) stabilizes the β phase by solid solution in the base material and has the effect of improving cold workability, but if its content is less than 1%, the above effect (: the desired improvement effect) is not obtained, and on the other hand, if its content exceeds 2%, the hardness of cold-beating
:2701a and above, its content was set at 1 to 2%.

lcl Nb Nb component (= is also the same as the ■ component (-1 solid solution in the substrate and β
It has the effect of stabilizing the phase and thereby improving the cold evacuation, but if the content is less than 1%, the desired effect of improving the cold evacuation cannot be obtained; exceed.

Hv: 2701a with cold working at processing rate = 70% or more
Since it is difficult to ensure high hardness, the content is set at 1 to 2%. It has the effect of improving the hardness after machining, but if its content is less than 0.2%, the desired effect of improving the effect cannot be obtained, while if its content exceeds 0.1%, The cold workability is poor (H), and cracks are likely to occur during cold working with a beating rate of 0% or more, so the content should be increased from 0.2 to
It was set at 0.3%.

These components C: are dissolved in solid solution in the base material and have the effect of further improving the hardness after strong electric work and cold working, so special orders for these are required. If the content is less than 0.1%, the desired effect cannot be obtained; on the other hand, if the content exceeds 0.5%, the cold processing (2) Since it becomes impossible to perform cold working with a work efficiency of 0% or more, the content was determined to be 0.1 to 0.5%. It is called the strong 1st component.

Ge I M.

Mo component C: has the effect of further improving cold workability, so when severe cold working is required (-
Necessary C: It is contained as required, but if its content is less than 0.1%, the above effect will not improve the efficiency by 1 to 1, while if its content exceeds 1%, Since the hardness of Hv:270 is not reached even by cold working of 0% or more, its content is determined to be 0.1 to 1%.

[Example of real power]

Next, the Ti alloy of the present invention will be specifically explained with reference to Examples.

First, a molten metal having the composition shown in Table 1 was prepared in a conventional vacuum arc melting furnace.

After casting into an ingot with a diameter of 140 m, this ingot (2) was hot-forged and hot-rolled under normal conditions to become a hot-worked material with a diameter of 10 mm, and then this hot-worked material ( After holding the temperature at near 00℃ for 1 hour, the Vickers hardness was measured under the condition of furnace cooling, and the area reduction rate of 70% or more shown in Table 1 (2) was measured. (
1; Therefore, 4: - Invention Ti alloys 1 to 20, Comparative Ti alloys 1 to 20.
8 and conventional Ti alloys 1 to 3 were manufactured, respectively.

The various Ti alloys obtained as a result were observed for the occurrence of cold working cracks (2), and the Vickers hardness was measured; , the tensile strength was measured before evaluating the strong electric current.The results are shown in Table 1.

It should be noted that in all of Comparative Ti alloys 1 to 8, the content t of any one of the constituent components (Table 1 (marked with a square mark)) is outside the scope of the present invention.

〔Effect of the invention〕

From the results shown in Table 1, in conventional Ti alloys 1 to 3,
Cold work (2) Those without cracking have low hardness after heavy electric work and cold work, while hardness after cold hammering is Hv:
It can be seen that those showing 270α or higher cannot avoid the occurrence of cold warping cracks, and it is impossible to manufacture eyeglass frames that require severe conditions with an IJO efficiency of near 0% or more.

On the other hand, Ti alloys 1 to 20 of the present invention all have excellent cold hammering properties, and even when cold working at a working rate of near 0% or more, cracks do not occur at all). Alloy 1 (
Pure Ti) +: It is clear that it has superior strength compared to pure Ti, and that it has a high hardness of Hv: 2701a or more in cold working at a working rate of near 0% or more (-).

On the other hand, if the ratio @Ti alloys 1 to 8 (-as seen (:), even if the amount of any of the constituent components is outside the scope of this invention, the cold workability and hardness after cold working It is clear that any of the custom orders will be inferior (:

As mentioned above, the Ti alloy of the present invention has much higher strength than pure Ti (Y), and has excellent cold workability equivalent to that of pure Ti (Y), and has a working rate of near 0% or more. It is possible to cold-work under the harsh conditions of Made a (
If two units are used, it becomes possible to make a lightweight unit, and furthermore, it has industrially useful special features such as being able to be used for six units in the manufacture of aircraft parts, vehicle parts, etc.

Claims (4)

[Claims] (1) Contains Al: 0.8 to 1.5%, V: 1 to 2%, Nb: 1 to 2%, Oxygen: 0.2 to 0.3%, and the rest is Ti and unavoidable impurities. A high-strength Ti alloy with excellent cold workability, characterized by having the following composition (the above weight %): (2) Contains Al: 0.8-1.5%, V: 1-2%, Nb: 1-2%, Oxygen: 0.2-0.3%, and further contains Zr, Sn, Fe , Cu, and Cr: 0.1 to 0.5%, and the remainder is Ti and unavoidable impurities (weight%). High strength Ti alloy with excellent machinability. (3) Contains Al: 0.8-1.5%, V: 1-2%, Nb: 1-2%, Oxygen: 0.2-0.3%, and further contains Mo: 0.1 A high-strength Ti alloy with excellent cold workability, characterized by having a composition (weight %) of ~1%, with the remainder consisting of Ti and unavoidable impurities. (4) Contains Al: 0.8-1.5%, V: 1-2%, Nb: 1-2%, Oxygen: 0.2-0.3%, and further contains Zr, Sn, Fe , Cu, and Cr: 0.1 to 0.5%, Mo: 0.1 to 1%, and the remainder is Ti and unavoidable impurities. %) with excellent cold workability.