JPS6364507B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an alloy, for example, a method for producing a Nb-based alloy that has excellent properties as an alloy for electrically conductive materials. As alloys for superconducting materials, Nb-Ti, Nb-
A variety of materials have been developed, including Ti-Zr, Nb-Ti-Ta, Nb-Ti-Hf, etc. Conventionally,
The method for manufacturing such an alloy is as follows:
Some examples are listed below. That is, a method in which raw material powder is press-molded into a lump-like green compact, the green compact is sintered to give it strength if necessary, and then arc melted or electron beam melted. A method in which raw material powder is melted using a boat-shaped mold, solidified into the shape of the mold, and then remelted as an electrode. A method in which multiple sheets of raw material formed for each component are bonded together to form an electrode, and then this electrode is arc melted. A method in which raw material powder is dropped into a molten liquid and dissolved. A method of enclosing powder or rod-shaped bodies in a pipe and dissolving them. A method in which raw materials are melted in a vacuum plasma melting furnace with a water-cooled copper hearth, and this is used as an electrode for vacuum arc melting. and so on. However, each of these conventional methods has the drawbacks of requiring a press forming process, a sintering process, a welding process for the compacted compact, etc., making the process complicated and increasing the cost. Method 2 has the disadvantage that it is unsuitable for mass production because it uses a boat-shaped mold for melting, and method 2 has the risk of high melting point materials such as Nb or Ta remaining unalloyed. Moreover, it has the disadvantage that it is quite difficult to make the alloy composition constant in the cross section of the electrode, and the method (2) has the disadvantage that there is a lot of loss due to scattering etc., which tends to reduce the yield. The pipe is expensive, and when melting in a normal vertical type, there is a risk that only the encapsulated material may fall during melting. It has the disadvantage that it is difficult to do so. The present invention has been made in view of the problems of the prior art described above, and is suitable for, for example, electrically conductive materials.
When manufacturing Nb-based alloys, it is important to ensure that there is no segregation or unmelted material in the ingot after alloy melting, that the melting yield is good, and at the same time, that the increase in manufacturing costs can be suppressed. The purpose is The present invention uses a melting furnace that uses a plasma arc as a heat source, such as a plasma arc melting furnace or a plasma arc skull melting furnace, to melt and solidify raw materials charged into a water-cooled melting vessel while maintaining an inert atmosphere. When producing an alloy by vacuum melting (VAR, EBR) using the obtained ingot as an electrode, Nb, Ta, Ti,
Using one or more selected from Zr, Hf, V, Mo, Si, and Sn, a powdered raw material among the raw materials is formed into a thin plate-like raw material by powder rolling, and then charged into the melting container. In one embodiment of the present invention, the raw materials include Nb powder, Ta,
1 selected from Ti, Zr, Hf, V, Mo, Si, Sn
In addition to the present invention, the powder raw materials are mixed at a predetermined ratio and formed into a thin plate-like raw material by powder rolling, and then charged into a melting container. In an embodiment of
Using Nb powder and one or more sponge-like raw materials selected from Ti, Zr, and Hf as raw materials, the Nb powder is formed into a thin plate-like raw material by powder rolling and charged into a melting container. , and the sponge-like raw material is charged into the melting container at a predetermined ratio, and in yet another embodiment of the present invention, as the raw material, Nb powder and
Using one or more powders selected from Ta, Ti, Zr, Hf, V, Mo, Si, and Sn and one or more sponge-like raw materials selected from Ti, Zr, and Hf, The powdered raw materials are mixed and formed into a thin plate-like raw material by powder rolling, and charged into a melting container, and the spongy raw material is replenished into the melting container so that a predetermined ratio is obtained. The raw materials include Nb powder, Ta, Ti, Zr, Hf,
When using one or more powders selected from V, Mo, Si, and Sn, as the raw material,
Using the scraps of the alloy to be manufactured, obtain alloy powder by hydrogenating, crushing, and dehydrogenating this scrap, and forming this alloy powder into a thin plate-shaped raw material by powder rolling and charging it into a melting vessel. Alternatively, a powder raw material can be obtained by using scraps of the necessary alloy components as raw materials and subjecting the scraps to hydrogenation, crushing, and dehydrogenation. The present invention will be further explained below using specific examples. Example 1 Here, commercially available Nb powder (particle size
(60 mesh or less) 20Kg and commercially available Ta powder (particle size
(60 mesh or less) 5 kg and commercially available Ti powder (particle size
(100 mesh or less) was mixed using 25 kg, and then powder rolled to form a thin plate material with a thickness of 0.5 mm and a width of 80 mm. Next, using a melting furnace that uses a plasma arc as a heat source, the thin plate-shaped raw material is charged into a water-cooled melting container, melted under an atmospheric pressure of 1 atm in an argon gas atmosphere, and then solidified. Vacuum arc melting (VAR) was performed using the ingot as an electrode. Next, the ingot obtained by the above process was cut longitudinally and examined for the presence of unmelted substances. As a result, no unmelted substances were found, and there was no segregation in the upper, middle, and lower parts of the ingot. was confirmed to be extremely small as shown in Table 1.

[Table] Example 2 Here, Nb plate scraps, Ti sponge, and Zr sponge were used as raw materials. That is, 30 kg of powder (particle size of 60 mesh or less) obtained by hydrogenating the above Nb plate scraps, pulverizing them, and dehydrogenating them was formed into a thin plate-shaped raw material with a thickness of 0.5 mm and a width of 80 mm by powder rolling.
This thin plate material was charged into the melting container of a plasma arc melting furnace, and in addition, 19 kg of Ti sponge and Zr
Mix and charge 1 kg of sponge into the dissolving container,
Atmospheric pressure in argon gas atmosphere
After melting by plasma arc heating under reduced pressure of 0.8 atm, it was solidified, and vacuum arc melting was performed using the obtained ingot as an electrode. Next, the ingot obtained by the above process was cut in the longitudinal direction and the presence or absence of undissolved matter was examined. As a result, no undissolved matter was observed in either macroscopic or microscopic observation, and there was very little segregation. confirmed. Example 3 Here, Nb powder, Ti powder, and Ti sponge were used as raw materials. That is, commercially available
20kg of Nb powder (particle size 60 mesh or less) and commercially available
5 kg of Ti powder (particle size of 100 mesh or less) was mixed and then powder rolled to a thickness of 0.5 mm.
Formed into a thin plate-like raw material with a width of 80 mm, and charged this thin plate-shaped raw material into the melting container of a plasma arc melting furnace.
Atmospheric pressure 1atm in argon gas atmosphere
It was dissolved under. Also, during this dissolution,
12 kg of Ti sponge was charged into the melting vessel, melted and solidified, and vacuum arc melting was performed using the obtained ingot as an electrode. Next, the ingot obtained by the above process was cut in the longitudinal direction and the presence or absence of undissolved matter was examined. As a result, no undissolved matter was observed in either macroscopic or microscopic observation, and there was very little segregation. confirmed. Example 4 Here, Nb-1%Ti-10%Hf was used as the raw material.
A Ti sponge and a Hf sponge were used. That is, the above-mentioned rod-shaped waste was hydrogenated, crushed, and then dehydrogenated. 23 kg of alloy powder (particle size 28 mesh or less) was powder rolled to a thickness of 0.5 mm and a width of 80 mm.
This thin plate material was charged into a melting vessel of a plasma arc melting furnace and melted under an atmospheric pressure of 0.8 atm in an argon gas atmosphere. Also, during this dissolution,
19.8Kg of Ti sponge and 7.7Kg of Hf sponge were charged into the melting vessel, adjusted to the target composition ratio of Nb-Ti-Hf alloy, solidified, and the resulting ingot was used as an electrode. As a result, vacuum arc melting was performed. Next, the ingot obtained by the above process was cut in the longitudinal direction and the presence or absence of undissolved substances was examined. As a result, no undissolved substances were observed in either macroscopic or microscopic observation. Furthermore, segregation was also extremely low. Comparative Example 1 Here, commercially available Nb powder (particle size
Using 20kg (60 mesh or less) and 18kg of Ti sponge, charge them into the melting melter of a plasma arc melting furnace, and reduce the atmospheric pressure in an argon gas atmosphere.
Melting was carried out by plasma arc heating under 1 atm. The weight of the ingot obtained here was 30 kg, and the melting yield was approximately 79%, which was an extremely poor result. In addition, when we conducted Nb analysis of the ingot, we found that
As shown in Table 2, segregation was quite large, and the value was extremely low compared to the target value of Nb (52.6%).

[Table] As can be seen from this result, if raw material powder is directly charged into the melting vessel of a plasma arc melting furnace, the melting yield will be considerably lower as the raw material powder will be blown away by the arc flame. It is difficult to obtain alloys with target components. Comparative Example 2 Here, Nb wire scrap (diameter 5~
10mm) 20kg and Ti sponge 20kg, these were mixed and charged into the melting container of a plasma arc melting furnace and melted by plasma arc heating under an argon gas atmosphere pressure of 1atm, and the obtained ingot was Vacuum arc melting was performed as an electrode. Next, when the ingot obtained by the above process was cut in the longitudinal direction and macrocorrosion was performed, a layered layer was found in the center.
The presence of undissolved Nb was observed. This is Nb
This is because the difference in melting point between Ti (melting point: 2468°C) and Ti (melting point: 1668°C) is quite large, and Nb does not completely melt and falls as it is. As described above, unfavorable results were obtained when Nb wire scrap was used as it was. In this regard, based on the present invention method,
Using Nb powder, this Nb powder is formed into a thin plate-like raw material by powder rolling, charged into a melting container, and melted by plasma arc heating, and then vacuum arc melting is performed using the obtained ingot as an electrode. When the ingot obtained here was cut in the longitudinal direction and macrocorrosion was carried out, the presence of undissolved Nb was not confirmed at all. This is because the method of the present invention uses a powder-rolled thin plate-like raw material, which has a density of approximately 60 to 80% of the true density, making it much easier to melt than wire scrap as it is. . As described above, according to the method of the present invention, a melting furnace using a plasma arc as a heat source is used to melt and solidify raw materials charged into a water-cooled melting furnace while maintaining an inert atmosphere. When manufacturing an alloy by performing vacuum melting using a melted ingot as an electrode, the powdered raw material is formed into a thin plate-like raw material by powder rolling and charged into the melting vessel. It is extremely superior in that it will not be blown away by the plasma arc and reduce the melting yield or deviate significantly from the target alloy composition, and there will be no segregation or unmelted materials in the ingot after alloy melting. In addition, since the initial dissolution is performed under an inert atmosphere, there is no need for exhaust equipment with large exhaust capacity to remove adsorbed gases specific to powders, and continuous mass production is possible. It also has very excellent effects, such as being able to easily suppress increases in manufacturing costs.

Claims (1)

[Claims] 1. Using a melting furnace using a plasma arc as a heat source,
In producing an alloy by melting and solidifying raw materials charged into a water-cooled melting vessel while maintaining an inert atmosphere, and performing vacuum melting using the obtained ingot as an electrode, Nb is used as the raw material. and,
Using one or more selected from Ta, Ti, Zr, Hf, V, Mo, Si, and Sn, the powdered raw material is formed into a thin plate-like raw material by powder rolling and placed in the melting vessel. A method for producing an alloy, characterized by charging the alloy. 2 As raw materials, Nb powder, Ta, Ti, Zr, Hf,
Using one or more powders selected from V, Mo, Si, and Sn, the powder raw materials are mixed in a predetermined ratio, formed into a thin plate-like raw material by powder rolling, and charged into a melting container. Claim No. 1
2. Method for producing the alloy described in Section 1. 3. Using Nb powder and one or more sponge-like raw materials selected from Ti, Zr, and Hf as raw materials, the Nb powder is formed into a thin plate-like raw material by powder rolling and charged into a melting container. 2. The method for producing an alloy according to claim 1, wherein said spongy raw material is charged into said melting container at a predetermined ratio. 4 As raw materials, Nb powder, Ta, Ti, Zr, Hf,
Using one or more powders selected from V, Mo, Si, and Sn and one or more sponge-like raw materials selected from Ti, Zr, and Hf, the powder raw materials are mixed to form a powder. The alloy according to claim 1, wherein the raw material in the form of a thin plate is formed by rolling and charged into a melting vessel, and the spongy raw material is replenished into the melting vessel to obtain a predetermined ratio. manufacturing method. 5. Use the scraps of the alloy to be manufactured as a raw material, hydrogenate, grind, and dehydrogenate the scraps to obtain alloy powder, form this alloy powder into a thin plate-shaped raw material by powder rolling, and place it in a melting vessel. A method for producing an alloy according to claim 1, 2 or 4, wherein the alloy is charged into a container. 6. Claim 1, wherein the powder raw material is obtained by using scraps of the necessary alloy components as raw materials and hydrogenating, crushing, and dehydrogenating the scraps.
4. A method for producing the alloy according to item 2, FIG. 3, or 4.