KR100742295B1 - Ni-w superconductor manufacturing process by continuous casting - Google Patents

Abstract

A manufacturing method for melting a metal nickel(Ni) is provided to be relatively inexpensive compared to powder in a vacuum induction melting furnace, adding tungsten(W) powder into melt, melting Ni-W alloy melt, and directly casting the molten Ni-W alloy into a sheet or wire rod using a continuous casting equipment. A method for manufacturing a Ni-W superconductor by continuous casting comprises the processes of: charging a metal nickel(Ni) into a crucible of a vacuum induction melting equipment, melting the metal nickel by induction heating, adding tungsten(W) powder into the nickel melt in a predetermined content, and melting the Ni-W alloy melt; extracting and casting a completely molten Ni-W alloy into a predetermined shape by a mold and a mold cooling and extracting device of a continuous casting equipment. The second process additionally includes the processes of; filling an inert gas into a chamber, and extracting and casting the molten Ni-W alloy into a sheet or wire rod shape at a temperature of 1650 deg.C or less by the continuous casting equipment; and cutting the sheet or wire rod that is extracted and cast into the predetermined shape to a desired length such that the cut sheet or wire rod can be used.

Description

Ni-Ｗ superconductor manufacturing process by continuous casting

The figure shows a Ni-W superconductor manufacturing process by the continuous casting method according to the present invention.

The present invention relates to a method of manufacturing nickel (Ni) -tungsten (W) superconductor, and more particularly, by using metal nickel (Ni), which is relatively inexpensive compared to powder, through a process of dissolution-continuous casting A method for producing a Ni-W superconductor.

Conventionally, in manufacturing a superconductor based on nickel (Ni) and having a content of tungsten (W) of 5 wt.% Or less, each of Ni and W powder is mixed and then encapsulated in a metal barrel, and then extruded or drawn out. It was manufactured and used in the form of a plate (plate) and a wire (wire) through a molding process such as processing. In the case of the superconductor manufacturing by the conventional powder molding process, the following problems were raised.

-Expensive Ni and W powder should be used as raw materials.

-It must go through the process of enclosing (canning) the metal container and peeling off the metal material surrounding the outside of the superconductor after plastic processing.

-Scrap (discard, etc.) occurs in the extrusion or drawing process, the material yield is reduced.

Therefore, the Ni-W superconductor manufactured by the conventional method not only has a very high production cost but also has a serious situation of contamination (carbon, etc.) of the superconductor due to many processes.

Accordingly, an object of the present invention is to solve the above-mentioned point, in order to solve the Ni-W alloy molten metal by dissolving metal nickel (Ni), which is relatively inexpensive compared to powder, in a vacuum induction furnace, and adding tungsten (W) powder to the molten metal. It provides a manufacturing method of casting directly into a plate and wire using a continuous casting device after melting.

Ni-W superconductor manufacturing method according to the continuous casting method of the present invention for achieving the above object, in the nickel (Ni) -tungsten (W) superconductor manufacturing method, (1) by vacuum induction dissolving apparatus ), Followed by adding a predetermined amount of tungsten (W) powder to melt the Ni-W alloy molten metal, and (2) drawing and casting the completely dissolved Ni-W alloy into a predetermined shape by a continuous casting apparatus. It includes a process to make.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The figure shows the manufacturing process of the Ni-W superconductor by the continuous casting method according to the present invention.

Continuous casting refers to a method of continuously producing simple cross-sectional products, such as slabs, billets, or round bars, of rolling materials directly from the molten metal. That is, the molten metal is injected into the water-cooling mold in advance to form a hardened molded product, which is pulled down with a roll to give water-cooled coagulation in the process and molded into a crystal short-lived shape. Cut this into the required length to make the product. The ingot casting process is advantageously omitted, which was first developed in the field of non-ferrous alloys, but in recent years it has been adopted in steelmaking. Round bars of cast iron are also made this way.

In describing the Ni-W superconductor manufacturing process by the continuous casting method, first, metal nickel (Ni) is charged into a crucible of a vacuum induction melting apparatus, and Ni charged into the crucible is dissolved by induction heating (step 1). Then, tungsten (W) powder is added to the Ni molten metal to a predetermined content, that is, 0.001 to 5% by weight or less (step 2). The added W is maintained at a predetermined temperature of 1700 ° C. or less until fully dissolved in the Ni molten metal (step 3). At this time, the chamber in which the crucible is located maintains a vacuum and the degree of vacuum is maintained at 10 ^-3 torr. In this case, refractory materials such as zirconia (ZrO 2) may be applied to the inner wall of the graphite crucible to prevent contact between the molten metal and the graphite crucible.

After the melting process of the Ni-W alloy molten metal is completed, the chamber is filled with an inert atmosphere such as argon (Ar) (1 atm), and then the mold, mold cooling, and take-out device of the continuous casting apparatus installed under the crucible is removed. Withdrawal and casting in a predetermined shape, i.e., plate and wire rod, at a temperature of 1650 ° C. or less (step 4). The draw rate during continuous casting should be 250 mm / min or less. During continuous casting, the shape of the starting bar is made according to the shape to be cast, that is, a plate with a width of 100 mm or less and a thickness of 30 mm or less and a line with a diameter of 15 mm or less, and the material is made of W, molybdenum (Mo), etc. Use a melting point metal.

The plate and wire rods drawn out and cast into a predetermined shape are cut into desired lengths and used for the production of superconductors (step 5).

The mold used in the Ni-W continuous casting apparatus uses graphite or Si3N4 ceramic containing Si3N4 or 10% BN alone or solidification occurs in the graphite mold. Si3N4 or Si3N4 ceramic containing BN is inserted at this point. Since BN and Si3N4 are relatively expensive compared with graphite, ceramics are used only where the molten metal reacts as solidification occurs. This is to minimize the contamination of the molten metal which may occur during solidification during continuous casting and to give lubricity to the surface of the continuous cast ingot.

As described above, the Ni-W superconductor manufacturing method according to the continuous casting method of the present invention can be expected to reduce the manufacturing cost by using a metal Ni, which is relatively inexpensive compared to the powder as raw materials, powder-canning- Instead of a number of complex molding processes such as extrusion or drawing-peeping-cutting, the process of melting-continuous casting can be simplified, resulting in cost reduction in production and improved material yield.

In addition, since it is possible to fundamentally block the cause of contamination that can occur in a number of processes it is possible to manufacture high-quality / high-purity Ni-W superconductor.

Claims (6)

In the nickel (Ni) -tungsten (W) superconductor manufacturing method, (1) charging metal nickel (Ni) into a crucible of a vacuum induction melting apparatus and dissolving by induction heating, and then dissolving the Ni-W alloy molten metal by adding a predetermined amount of tungsten (W) powder; And (2) A method of manufacturing Ni-W superconductors by the continuous casting method, comprising the steps of drawing and casting a Ni-W alloy completely dissolved by a mold, a mold cooling and a drawing apparatus of the continuous casting apparatus into a predetermined shape. delete The method according to claim 1, wherein in order to prevent carbon contamination of the molten metal when the Ni-W superconductor alloy is dissolved, a refractory made of zirconia (ZrO2) is coated on the inner wall of the crucible used for melting the Ni-W alloy. Ni-W superconductor manufacturing method by the casting method. The process according to claim 1, wherein the step (2) (2a) filling the inside of the chamber with an inert atmosphere and then drawing and casting it into a plate and wire shape at a temperature of 1650 ° C. or lower by a continuous casting apparatus; And (2b) A method of manufacturing a Ni-W superconductor by the continuous casting method, comprising the step of cutting and using a plate and a wire rod drawn and cast into a predetermined shape to a desired length. The method of manufacturing a Ni-W superconductor according to the continuous casting method according to claim 4, wherein a Si3N4 ceramic containing Si3N4 or 10% BN is inserted into an inner wall of the graphite mold used for the continuous casting. The method of manufacturing a Ni-W superconductor according to claim 4, wherein a high melting point metal of tungsten (W) or molybdenum (Mo) is used as a starting bar during the continuous casting.

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