JPH06192708A - Method for forming cuttings of high-melting-point active metal and its alloy - Google Patents

Abstract

PURPOSE:To obtain the material with the content of the volatile alloy component easily adjustable and the material for the bar, tube, shape, etc., with a simple device as compared with the conventional one in which cuttings are remelted and with a small consumption of energy. CONSTITUTION:The cuttings of a high-m.p. active metal such as titanium and zirconium or their alloy are crushed, cleaned and then put in a capsule, and the cuttings are compressed by a press so that the ratio of the bulk density to the true sp.gr. is controlled to 50%, degreased, sealed and then hot-extruded into the bar, tube and shape. When the cuttings easy to form are used, the cuttings are compacted by extrusion, then put in a capsule and treated by the same process as before.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method for recycling (recycling) high-melting-point active metal chips, particularly titanium, zirconium and their alloy chips.

[0002]

2. Description of the Related Art Titanium (Ti), which is a high melting point active metal,
Zirconium (Zr) and alloys thereof are widely used in various fields. In particular, titanium and titanium alloys have high specific strength, excellent corrosion resistance and heat resistance,
It is used as an important member in various fields such as marine relations, chemical industry, and nuclear power. In particular, as an aircraft material that places importance on specific strength, it is an indispensable material for engine members, airframe structural materials, and the like.

These materials require a large amount of electric power for refining, are complicated and expensive in the manufacturing process, and have a certain size for forging precision products such as aircraft engine parts. Since it is cut and formed from the material, a large amount of cutting waste is generated. Since the recycling of this cutting waste has a great influence on the economical efficiency in the industry in which high melting point active metals such as titanium and titanium alloys are used as raw materials, the recycling has been actively made from the past. As a method,
Taking the case of titanium or titanium alloy as an example, the following methods can be given. At present, the method (a) is mainly used.

(A) A method in which raw material sponge titanium is mixed with cutting scraps and pressed into a compact, and the compact is used as a consumable electrode and melted in a vacuum arc furnace.

(B) A method in which cutting waste is melted by an electron beam alone or mixed with titanium sponge.

(C) A method in which cutting dust is melted alone or in admixture with titanium sponge to perform plasma arc melting.

However, all of the above recycling methods require a step of remelting the cutting chips, and then, after the steps of hot rough forging, hot die forging, cutting, etc., a product of titanium or titanium alloy or A large amount of energy is required to make it into a material, and a large amount of cutting waste is generated again. In addition, in the method (a), in order to secure the strength of the compact used as the consumable electrode, the mixing ratio of cutting waste is set to 5
There is a constraint that it must be less than 0%. Further, in the method (b), since the volatile metal such as aluminum is evaporated because the melting is performed in a high vacuum, when such a metal is added as an alloy component, it is not possible to accurately control its content rate. Have difficulty.

[0008]

DISCLOSURE OF THE INVENTION The present invention has a simple process and does not require a large amount of energy when recycling the cutting waste of a high melting point active metal and its alloy as a raw material, and also has a restriction in terms of raw material mixing. It is an object of the present invention to provide a molding method for cutting chips, which is easy to adjust the content rate of alloy components which are not easily received and easily volatilize.

[0009]

The gist of the present invention resides in the following molding method for cutting chips.

After crushing and cleaning cutting waste of a high melting point active metal or its alloy, it is put in a capsule, compressed by a press so that the true specific gravity ratio (the rod specific gravity relative to the true specific gravity) becomes 50% or more, and deaerated. A method for forming cutting waste of a high melting point active metal and its alloy, which comprises forming a rod, a tube and a shape by hot extrusion after sealing.

After crushing and cleaning the cutting waste of the high melting point active metal or its alloy, the true specific gravity ratio is 50% by pressing.
Molding of cutting waste of high melting point active metal and its alloy characterized by compressing, encapsulating, deaerating and sealing as described above, then molding rod, tube and shape by hot extrusion Law.

Typical examples of the cutting scraps to which the present invention is applied are cutting scraps made of titanium, zirconium, a titanium alloy or a zirconium alloy. )Such,
Metal chips, which have a high melting point and are thermodynamically active, are mentioned.

The invention of (1) is intended for cutting waste having good moldability, and after crushing and cleaning, it is compressed in a mold as it is so that the true specific gravity ratio becomes 50% or more, then put in a capsule and deaerated. Process after sealing.

[0014]

The method of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the whole steps of the method of the present invention. As shown in this figure, the method of the present invention directly extrudes cutting chips by hot extrusion to obtain rods, pipes, profiles and the like. The feature is that you can obtain the material.

The cutting dust may be a cutting dust of a high melting point active metal, a cutting dust of an alloy thereof, or a mixture of two or more kinds thereof. The point is that it is sufficient if it is a cutting waste that can obtain a material having a desired chemical composition.

In the crushing process, the length of cutting waste is 5 to 25 mm.
Cut into small pieces.

The purpose of the cleaning step is to prevent carbon (C), oxygen (O), nitrogen (N) and the like from being picked up and to improve the density during extrusion. In order to meet this purpose, the pickling treatment may be carried out under the conditions which are usually performed depending on the kind of the high melting point active metal.

In the step of pressing, as described above, the capsule may be filled and pressed, or may be inserted into the capsule after pressing, depending on the formability of the cutting waste. In addition,
As the material of the capsule, it is necessary that it does not react with the cutting wastes that are the raw material at the processing temperature, and when titanium or titanium alloy is pressed, a capsule made of mild steel or titanium is suitable.

The press treatment is performed so that the true specific gravity ratio becomes 50% or more. This is because the true specific gravity ratio is 50 even when the capsules are simply vibrated or pressed by hand without being pressed after being filled, or even after being pressed.
If it is less than%, buckling of the capsule occurs in the extrusion container and deep wrinkles occur, which appear as surface defects of the extruded material.

FIG. 2 is a diagram showing the process of FIG.
(A) is a press process, in which the cutting waste 1 charged in the bottomed capsule 2 is put into the mold 3 and compressed by the upper punch 4, and (b) is degassed into the capsule 2 taken out from the mold 3. In the state where the capsule lid 5 provided with the working tube 6 is welded, (c) is degassed from the degassing tube 6 to evacuate the inside of the capsule 2 and then a part of the tube 6 (7 in the figure) The state of being crimped and welded and sealed, (d) shows the state of extruding a capsule filled with cutting chips and sealed.

For example, in the case of titanium and zirconium, it is preferable to carry out under the following conditions.

[0023] Regarding the extrusion temperature, give some degree of deformation resistance and increase the internal stress applied to the material to give the adhesion of cutting chips. Further, since it is necessary to suppress the coarsening of the structure, the upper limit is set to 1373K, and the lower limit is set to 107 in order to prevent the generation of cavities and improve the adhesion of cutting chips.
3K. The lower limit of the extrusion ratio is 5 in order to improve the adhesion. The upper limit can be suppressed to about 12 in terms of equipment and crack prevention. Regarding the heat treatment of the extruded material, it is necessary to carry out it in the sense of homogenizing the adhesive part by diffusion,
There is no problem under conventional conditions.

After extrusion and heat treatment, mechanical cutting or pickling treatment is performed to remove the capsules, whereby a material such as a rod is obtained.

[0025]

EXAMPLE A titanium alloy having the composition shown in Table 1 (Ti-6% A
(1-4% V) cutting material as a raw material, crushed to a thickness of 0.5 mm, width and length of about 10 mm, and then pickled with hydrofluoric nitric acid,
Washed with water, washed with alcohol, vacuum-dried, inner diameter 48 mm
No. 1 pure titanium capsule, and press-treated to give a rod specific gravity of 2.48 g / cm ³ (true specific gravity ratio of 56%). The height of the cutting waste layer was 56 mm.

Extrusion was carried out according to the process shown in FIG. Extrusion conditions are temperature: 1273K, extrusion ratio =
5.8, heat treatment: 1023K, 24Hr.

By extrusion, diameter 20 mm, length: 1
A sound alloy rod of 85 mm and a true specific gravity ratio of 100% was obtained.

Table 1 also shows the chemical composition of the alloy material in the state of being annealed at 1023K after extrusion. The content of each component was almost the same as that of the raw material, and no decrease in the Al content, which was likely to evaporate, was observed. Also, the microstructure is fine,
It was good.

Table 2 shows the tensile test results of the alloy material after annealing. Good results were obtained in terms of yield strength, tensile strength and elongation.

[0030]

[Comparative Example] Using the same raw material as in the example, the same pure titanium capsule had a specific gravity of 2.03 g / cm ³ (a true specific gravity ratio of 46).
%) And extruded under the same conditions as in the example, wrinkles were generated on the surface of the extruded material, some capsule surfaces were cracked, and internal chips were exposed. Seen, it is hard to say that it is a healthy alloy.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

EFFECT OF THE INVENTION The molding method of cutting waste of the present invention as a method of recycling cutting waste of high melting point active metal and its alloy as a raw material has a step as compared with the conventional method which requires remelting of cutting waste. Simple and low energy consumption. In addition, it is easy to adjust the content rate of alloy components that easily volatilize without being restricted by the raw material mixing surface, and to directly remove Ne from the cutting waste.
It is possible to obtain a material such as ar-Net-Shape (product approximate size) or a material such as a rod.

[Brief description of drawings]

FIG. 1 is a diagram showing the overall steps of the method of the present invention.

FIG. 2 is a diagram showing the process of FIG. 1, in which (a) is a pressing process, (b) is a capsule lid welding process, and (c) is a process.
Is a deaeration / sealing process, and (d) is an extrusion process.

Claims (3)

[Claims] 1. Crushing and cleaning the cutting waste of a high melting point active metal or its alloy, encapsulating it, compressing it by a press so that the true specific gravity ratio becomes 50% or more, deaeration and sealing, A method for forming cutting waste of a high melting point active metal and its alloy, which comprises forming a rod, a tube and a profile by hot extrusion. 2. The true specific gravity ratio is 50% by pressing after crushing and cleaning cutting chips of a high melting point active metal or its alloy.
Molding of cutting waste of high melting point active metal and its alloy characterized by compressing, encapsulating, deaerating and sealing as described above, then molding rod, tube and shape by hot extrusion Law. 3. Molding of cutting waste of high melting point active metal and its alloy according to claim 1 or 2, wherein the cutting waste of high melting point active metal or its alloy is cutting waste of titanium, zirconium, titanium alloy or zirconium alloy. Law.