JP2002122386A - Water-cooled copper crucible for levitational melting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a reaction of a copper of a stock of a crucible with a molten metal when the metal is contact held in the crucible in melting a material containing aluminum and another low melting point alloy as main components. SOLUTION: A levitational melding apparatus melts the metal material thrown in the water-cooled copper crucible by induction heating by levitating the material by an electromagnetic repulsion force by exciting an induction coil disposed on an outer peripheral side of the crucible by using a high-frequency power source. In this apparatus, an inside surface of the crucible 1 at least from bottom to a height opposed to a maximum molten metal height or higher is coated with an insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-cooled copper crucible for levitation melting for alloying a high melting point metal into a low melting point metal.

[0002]

2. Description of the Related Art FIG. 7 shows a configuration diagram of a conventional example. This FIG.
The water-cooled copper crucible 1 comprises a plurality of electrically insulated segments 1a arranged inside a circular induction coil 2 through a slit 7 in the circumferential direction of the induction coil 2. The inside of the water-cooled copper crucible 1 is hollowed out, and the material to be melted is put in the hollowed-out portion. The magnetic flux generated by exciting the induction coil 2 penetrates into the water-cooled copper crucible 1 from the gap of the slit and interlinks with the material to be melted. The segment 1a constituting the water-cooled copper crucible 1 is cooled so as not to be heated by water or the like.

The high-frequency current applied to the induction coil 2 is
An eddy current is induced in each of the electrically isolated segments 1a, and a current is further induced in the object to be heated. When a metal, not to mention a non-magnetic material, is heated to a Curie point or higher and becomes a non-magnetic material, the metal becomes a non-magnetic material, and the eddy current induced in the segment 1a of the water-cooled copper crucible 1 and the eddy current induced in the metal are opposed to each other. Since the portions are opposite to each other, they are magnetically repulsive. Since the crucible is fixed, if the levitation force acting on the object to be heated is greater than the weight of the object to be heated, the object to be heated floats away from the water-cooled copper crucible 1.

The object to be heated generates heat due to resistance loss and continues to be heated to become molten metal 4. For this reason, the whole to-be-heated thing or the most part melt | dissolves in the water-cooled copper crucible 1 in a non-contact state. In this dissolving method, there is no contaminant from the water-cooled copper crucible 1, and dissolving is performed in an inert gas replacement atmosphere, so that dissolving without deteriorating the purity of the raw material is possible.

[0005] Further, since the scouring effect due to the degassing effect can be expected by performing in a high vacuum atmosphere, it is suitable for dissolving high purity materials. Pure metals and alloys can be melted from a pure metal base material or from a remelted material that has already been alloyed. Particularly when melting alloys, batch melting from the base material and component adjustment during melting can be performed freely. There are advantages. By casting the molten metal into a mold, it is possible to produce a high-purity cast product, which is suitable for dissolving active metals such as titanium, high-melting metals (chromium, niobium, molybdenum), silicon, and the like.

Further, since the electromagnetic force acting on the crucible is strong, the molten metal is electromagnetically stirred, and is suitable for alloy melting in which a uniform composition is required. There are various methods for taking out the product melted by the flotation melting apparatus, but there is a method in which an outlet 6 is provided at the bottom of the water-cooled copper crucible 1 and the molten metal is continuously or intermittently taken out from the outlet 6.

In this bottom tapping method, a mold, a roll, and an atomizer are installed below the outlet 6, so that the above-mentioned cast product of high-purity pure metal or high-purity alloy, wire, ribbon,
It is possible to obtain powder and the like. In addition, the outflow port 6 is used to prevent the molten metal from leaking therefrom when the molten metal is small and sufficient buoyancy cannot be imparted, such as in the initial stage of melting, and to prevent the molten metal from flowing out due to the loss of buoyancy during a power failure. In this case, the stopper 5 can be detached.

[0008]

In recent years, molybdenum, titanium, or the like has been used as an additional element for the purpose of improving the characteristics of aluminum in applications such as wiring materials and target materials for reflective films. In this case, the alloy obtained from the aluminum and the additive material may be in the form of a casting, a powder, or in various forms. In any case, it is required that the material be of high purity and have no variation in composition. Is done.

When smelting such a material, a levitation melting apparatus is considered to be suitable for the above-mentioned reason.
The following problems may occur. As an example, Al-
Ti2at. % Pure metal base material, Al and Ti are prepared, and these are floated and dissolved to obtain a uniform composition of Al-Ti2a.
t. Consider the production of a% alloy.

First, the water-cooled copper crucible of the levitation melting apparatus has a surface temperature of the crucible kept low by water cooling, but the crucible itself is heated by an eddy current flowing in the crucible, so that the crucible itself is not energized. The temperature of the crucible surface is high. Al-Ti2at. In%,
From the diagram of the metal plate of Al and Ti shown in FIG. 5, the solid-liquid interface temperature is about 1100 ° C. This is because the temperature of the molten metal must be 1100 in order to melt the above composition.
It means that it is necessary to take out the alloy after the alloy has been diffused while maintaining the temperature at a temperature of the molten metal exceeding ℃.

Next, looking at the Al-Cu alloy phase diagram shown in FIG. 6, the solid-liquid boundary temperature of the Al-Cu alloy is A
lat. Looking from 100% to the Cu side, Cu
The solid-liquid interface temperature rises with the melting point of Al 66
0 ° C. and gradually decreased from Al-Cu17 at. %, The local minimum value is 548 ° C. In these matters, the melt containing Al as a main component is 1100 ° C.
This indicates that, when the molten metal is kept at a temperature of more than 00 ° C., the Cu in the water-cooled copper crucible and the molten metal Al may be alloyed in a portion where the molten metal contacts the water-cooled crucible. The problem is that the molten metal is contaminated by the incorporation of Cu. Water-cooled copper crucibles cannot be used repeatedly. If erosion due to alloying progresses, the copper crucible is eroded to the point where the cooling water passes, causing steam explosion, etc. It may indicate that there is a possibility of an accident.

[0012] These phenomena may also be caused by the water-cooled copper crucible reacting even when the alloy containing a low melting point metal other than aluminum (such as tin) as a main component is kept at a high temperature. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has an object to solve the problem when a molten metal is held in contact with a crucible when melting a material mainly containing aluminum or another low melting point alloy. Another object of the present invention is to provide a water-cooled copper crucible for levitation melting in which copper, which is a material of the crucible, does not react with molten metal.

[0013]

According to a first aspect of the present invention, an induction coil disposed on the outer peripheral side of a water-cooled copper crucible is excited by using a high-frequency power supply, and is introduced into the water-cooled copper crucible. In a levitation melting apparatus, which floats the melted metal material by electromagnetic repulsion and melts it by induction heating, it is necessary to coat the inner surface of the water-cooled copper crucible with an insulator from at least the bottom to a height not less than the height facing the maximum hot water. Features.

According to the above-mentioned structure, when ceramics such as zirconia is used as a coating material, a strong protective film is formed, and even if a superheated high-temperature molten metal comes into contact with the crucible, the water-cooled copper crucible will not be damaged. It is possible to do so. In addition, the protective coating is water-cooled by a water-cooled copper pot. If the temperature of the molten metal is lower than the heat-resistant temperature of the material, the protective coating material is not mixed into the molten metal even if the molten metal is in contact with and held on the protective coating. High purity dissolution can be maintained, and the water-cooled copper crucible can be used repeatedly.

According to a second aspect of the present invention, the induction coil disposed on the outer peripheral side of the water-cooled copper crucible is excited by using a high-frequency power source, and the metal material put into the water-cooled copper crucible is levitated by electromagnetic repulsion to induce induction. In a flotation melting apparatus that melts by heating, an insulator is placed between the segments of a water-cooled copper crucible composed of side-by-side segments, or in the gap between the slits of a water-cooled copper crucible formed by excavating a longitudinal slit in the body. It is characterized by coating.

According to the above construction, a strong protective film is formed between the segments or in the slits as in the case of the first aspect, so that the superheated high-temperature molten metal is formed between the segments of the water-cooled copper crucible or between the segments. It is possible to prevent the water-cooled copper crucible from being melted even when it enters the gap of the slit. The protective coating is water-cooled by a water-cooled copper crucible. If the temperature of the molten metal is lower than the heat-resistant temperature of the material, the molten metal contacts and is held on the protective coating while entering between the segments or the gap between the slits. In addition, the protective coating is not mixed into the molten metal, so that high-purity dissolution can be maintained, and the water-cooled copper crucible can be used repeatedly.

According to a third aspect of the present invention, there is provided a water-cooled copper crucible for fusing and melting according to the first or second aspect, wherein at least a portion including an upper surface of a plug inserted into a bottom hole of the water-cooled copper crucible is provided with an insulating material. Characterized by coating. With the above configuration, a strong protective coating is formed on the plug in the same manner as in claim 1, so that even if the superheated high-temperature molten metal contacts the top surface or side surface of the tap, the tap does not melt. It is possible to do so.
Also, the protective coating is water-cooled by a tap, and if the temperature of the molten metal is lower than the heat-resistant temperature of the material, the protective coating enters the molten metal even if the molten metal is in contact with and held on the protective coating on the top surface or side surface of the tap. Is not mixed, and a high-purity alloy casting and a high-purity alloy material can be manufactured by opening a high-purity melting and tapping plug and discharging the molten metal. The tap can be used repeatedly.

According to a fourth aspect of the present invention, there is provided a water-cooled copper crucible for levitation melting according to any one of the first to third aspects, wherein aluminum is used as a main component (50 at.% Or more).
The invention is characterized in that the alloy is made from an alloy using the alloy material as a base material or a remelted material that has already been alloyed. According to a fifth aspect of the present invention, there is provided a water-cooled copper crucible for levitation melting according to any one of the first to third aspects, wherein the aluminum of the fourth aspect is used as a main component (50a
t. % Or more) in the base material or in the remelted material already metallized, zirconium, yttrium, vanadium, molybdenum, silicon, nickel, titanium, chromium, having a melting point of 1000 ° C. or more. It is characterized in that a material containing at least one metal such as niobium, cerium, hafnium, tantalum, tungsten or the like is melted and alloyed.

According to a sixth aspect of the present invention, there is provided a water-cooled copper crucible for levitation and melting according to any one of the first to third aspects, wherein the aluminum of the fourth aspect is used as a main component (5).
0 at. % Or more), the alloy composition of the base material or the alloy composition of the remelted material that has already been alloyed, and the solid-liquid interface temperature of the alloy composition is 860 ° C or more. It is characterized by.

The invention of claim 7 provides a water-cooled copper crucible for levitation melting according to any one of claims 1 to 3, wherein tin, zinc, magnesium, indium, antimony or the like other than aluminum is used. The present invention is characterized in that a base metal material mainly composed of a low-melting-point metal and a low-melting-point metal is alloyed from a base material or an already alloyed remelted material.

According to an eighth aspect of the present invention, there is provided a water-cooled copper crucible for levitation melting according to any one of the first to third aspects, wherein the low melting point metal according to the seventh aspect is used as a main component (50%).
at. % Or more) in a base material or a re-melted material which has already been alloyed, having a melting point of 1000 ° C. or more, zirconium, yttrium, vanadium, molybdenum, silicon, nickel, titanium, chromium, niobium, cerium, It is characterized in that a material containing at least one metal such as hafnium, tantalum, tungsten, iron, cobalt, neodymium, palladium and the like is alloyed and melted.

According to a ninth aspect of the present invention, there is provided a water-cooled copper crucible for levitation and melting according to any one of the first to third aspects, wherein the low melting point metal according to the seventh aspect is replaced with an earth component (50%).
at. % Or more), the alloy composition of the base material
Or the solid phase of the alloy composition of the remelted material already alloyed
The liquidus temperature is 2
It is characterized in that a material having a temperature higher than 00 ° C. is melted.

According to the above-mentioned constitution of the present invention, aluminum is used as the main component (5) using a water-cooled copper crucible.
0 at. % Or more) (including at least one metal such as zirconium, yttrium, vanadium, molybdenum, silicon, nickel, titanium, chromium, niobium, cerium, hafnium, tantalum, and tungsten having a melting point of 1000 ° C. or more). Alloy of the material,
And alloys whose materials have a solid-liquid interface temperature of 860 ° C or higher) and alloys containing low-melting metals other than aluminum, such as tin, zinc, magnesium, indium, and antimony, as main components. The base material is an alloy (especially 100
Zirconium, yttrium, vanadium, molybdenum, silicon, nickel, titanium,
Alloys of materials containing at least one metal such as chromium, niobium, cerium, hafnium, tantalum, tungsten, iron, cobalt, neodymium, palladium, etc., and the solid-liquid interface temperature of the alloy composition as the main component An alloy of a material whose temperature is 200 ° C. or higher from the melting point of a certain low melting point metal can be melted.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a structural view of a main part of an embodiment of the present invention, FIG. 2 is a schematic view of a segment coated on the surface of FIG. 1, and FIG. FIG. 4 shows a schematic view of the segments, and FIG. In FIGS. 1 to 3,
The parts denoted by the same reference numerals as those in the conventional example have approximately the same functions, and therefore description thereof will be omitted. In FIGS. 1 to 3, a protective coating 8 sprayed with ceramics, such as zirconia, is coated on the inner surface of the water-cooled copper crucible 1, the gap between the slit 7, and the entire spout 5 set at the crucible outlet 6. .

In the above zirconia spraying, the surface to be sprayed of the copper crucible or the tap 5 is buried with sand blast or the like to give fine irregularities to improve the penetration of the sprayed material into the copper, and then become familiar with the zirconia sprayed material. After spraying a good nickel-chromium alloy and undercoating, zirconia is finish-sprayed. Instead of zirconia, ceramics such as alumina, yttria, magnesia, and calcia may be used.

When a metal is put into the water-cooled copper crucible 1 and a high-frequency current is supplied from the high-frequency power supply 3 to the induction coil 2, the magnetic flux generated by the high-frequency current induces an eddy current in the segment 1a of the water-cooled copper crucible. At the same time, the metal enters the gap between the segments 1a, induces an eddy current in the metal charged in the crucible, and floats and melts the metal to form the molten metal 4. The molten metal 4 is removed from the outlet 6 by tapping the tap 6 and poured downward to be cast into a mold or the like.

[0027]

According to the present invention, when a material containing aluminum or another low melting point alloy as a main component is produced in a levitation melting apparatus, an alloy containing a composition element having a melting point of 1000 ° C. or more, or Conditions for satisfying one or both of the cases in which a solid phase-liquid phase interface temperature of a desired alloy composition is melted to a temperature of 200 ° C. or more from the melting point of a low melting point metal such as aluminum as a main component. At
Aluminum and other low-melting metals in the molten metal maintained at 200 ° C or higher from the superheat of the main component metal do not react with the water-cooled copper crucible, and maintain high purity melting without contamination from the crucible. Also, it is effective in manufacturing a high-purity material casting or a high-purity material product.

Further, since there is no erosion of the water-cooled copper crucible, there is an effect that the crucible can be used repeatedly and a danger of a steam explosion generated when the erosion progresses can be avoided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of the present invention.

FIG. 2 is a schematic view of a segment coated on the surface of FIG. 1;

FIG. 3 is a schematic view of a segment coated on the side surface of FIG. 1;

FIG. 4 is a view of the tap of FIG. 1 coated on the tap;

FIG. 5 is an alloy phase diagram of Al—Ti.

FIG. 6 is an alloy phase diagram of Al—Cu.

FIG. 7 is a configuration diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 water-cooled copper crucible 1a segment 8 protective coating 8

Claims (9)

[Claims] An induction coil disposed on the outer periphery of a water-cooled copper crucible is excited by using a high-frequency power source, and a metal material charged in the water-cooled copper crucible is levitated by electromagnetic repulsion and melted by induction heating. A water-cooled copper crucible for levitation and melting, characterized in that an insulating material is coated on an inner surface of the water-cooled copper crucible from at least the bottom surface to a height not less than the maximum hot water height. 2. A flotation melting apparatus in which an induction coil arranged on the outer peripheral side of a water-cooled copper crucible is excited by using a high-frequency power source, and a metal material put in the water-cooled copper crucible is levitated by electromagnetic repulsion and melted by induction heating. Flotation characterized by coating an insulator between the segments of a water-cooled copper crucible comprising side-by-side arranged segments or between the segments or a slit of a water-cooled copper crucible formed by excavating a vertically long slit in a body. Water-cooled copper crucible for melting. 3. A water-cooled copper crucible for levitation and melting according to claim 1, wherein a portion including at least an upper surface of a plug inserted into a bottom hole of the water-cooled copper crucible is coated with an insulator. Water-cooled copper crucible for flotation melting. 4. An alloy using a water-cooled copper crucible for levitation and melting according to any one of claims 1 to 3 and comprising an alloy material containing aluminum as a main component (50 at.% Or more) as a base material. Or a water-cooled copper crucible for levitation melting, wherein an alloy is melted from a remelted material that has already been alloyed. 5. An alloy material containing aluminum as a main component (50 at.% Or more) according to claim 4, using the water-cooled copper crucible for levitation and melting according to any one of claims 1 to 3. Zirconium having a melting point of 1000 ° C. or more in the base material or in the remelted material already metallized,
Alloy melting a material containing at least one metal such as yttrium, vanadium, molybdenum, silicon, nickel, titanium, chromium, niobium, cerium, hafnium, tantalum, tungsten, iron, cobalt, neodymium, palladium, etc. A water-cooled copper crucible for levitation melting. 6. An alloy material containing aluminum as a main component (50 at.% Or more) according to claim 4, using the water-cooled copper crucible for levitation and melting according to any one of claims 1 to 3. The solid-liquid interface temperature of the alloy composition of the base material or the alloy composition of the remelted material already alloyed is 860.
A water-cooled copper crucible for levitation melting, characterized by alloying a material having a temperature of at least ℃. 7. A water-cooled copper crucible for levitation and melting according to claim 1, wherein a low melting point metal other than aluminum, such as tin, zinc, magnesium, indium and antimony, is used as a main component. A water-cooled copper crucible for levitation melting, wherein an alloy-based material having a melting point metal is alloyed from a base material or an already alloyed remelted material. 8. A base comprising the low melting point metal according to claim 7 as a main component (50 at.% Or more) using the water-cooled copper crucible for levitation and melting according to any one of claims 1 to 3. Zirconium, yttrium, vanadium, molybdenum, silicon, nickel, titanium, chromium, niobium, cerium, hafnium, tantalum, tungsten having a melting point of 1000 ° C. or higher in a gold-based material as a base material or a re-melted material that has already been alloyed. A water-cooled copper crucible for levitation melting, characterized by alloying a material containing at least one metal such as iron, cobalt, neodymium, and palladium. 9. An alloy comprising the low melting point metal according to claim 7 as an earth component (50 at.% Or more) using the water-cooled copper crucible for levitation and melting according to any one of claims 1 to 3. A material whose base material has a solid-liquid interface temperature of 200 ° C or more from the melting point of the low-melting-point metal whose main component is the alloy composition of the base material or the alloy composition of the remelted material that has already been alloyed. A water-cooled copper crucible for flotation melting characterized by being manufactured.