JP2001293550A - Method and apparatus for producing microcrystalline ingot - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A high melting point alloy can be melted by drastically reducing the mixing of impurities, and segregation and coarsening of particles during condensation of the molten metal can be effectively suppressed. The present invention provides a method and apparatus for producing a microcrystalline ingot capable of stably producing a large ingot having a uniform and high strength as a whole. SOLUTION: A high-frequency induction electrolytic furnace 12 having a hollow crucible 12a having a lower opening, an ingot case 14 located below the electrolytic furnace and having an upper opening, and a lower opening of the crucible and an upper opening of the ingot case are hermetically sealed. And a throat 16 communicating therewith. Also, the throat closing step S
1. The material sealing step S2, the evacuation step S3, the material melting step S4, the plug melting step S5, and the rapid solidification step S6 are performed to levitation melt the material 10 which has been adjusted and refined by high frequency induction heating,
The plug in the throat is melted by high-frequency induction heating, and the molten metal is dropped into the ingot case through the throat and rapidly solidified for fine crystallization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a microcrystalline ingot which suppresses segregation at the time of condensation and coarsening of particles to produce a large ingot having a small amount of impurities and a uniform and high strength as a whole.

[0002]

2. Description of the Related Art Large parts that require high strength at high temperatures, such as turbine disks, long shafts, and casings, which constitute a jet engine, have conventionally been produced mainly by casting a large amount of molten metal at a high speed to produce an ingot. It was manufactured by forging and machining ingots.

[0003] Conventionally, the production of such ingots is as follows.
High-speed induction melting furnace (Vacuum Induction)
Melting & Casting, vacuum casting (V
acuum Casting, Vacuum arc remelting furnace (Consumable Electrode Vac)
uum Arc Furnace), Electrosulfur® Remelting Furnace (Electro Remelting F)
and an integral ingot of a size required for the target large part.

[0004]

In recent years, as the performance and jet temperature of jet engines have been improved, high melting point alloys containing aluminum, titanium, tungsten, molybdenum and the like have been used as their materials. But,
Such a high melting point alloy has a problem that any of the above-mentioned melting and casting means is liable to cause segregation and coarsening of particles during condensation after melting, and to easily cause defects in an ingot.

[0005] Here, segregation means a non-uniform distribution of impurities, inclusions, and alloy components in the alloy, and is one of the serious defects that cannot exert the original strength of the alloy. It is also known that alloy strength is greatly reduced by coarsening of particles.

That is, despite the fact that large components such as turbine disks require high strength at high temperatures, conventional ingot manufacturing methods require ingots of the required size due to segregation and coarsening of particles. It was difficult to make the whole homogeneous and of sufficiently high strength, making it virtually impossible. Further, the conventional ingot has a problem that it is difficult to avoid a part of the crucible (crucible) used at the time of melting from peeling and mixing, and as a result, impurities are often mixed.

The present invention has been made to solve such a problem. That is, an object of the present invention is to significantly reduce the mixing of impurities and to melt a high melting point alloy, and to effectively suppress segregation and particle coarsening during condensation of the molten metal, Accordingly, it is an object of the present invention to provide a method and apparatus for producing a microcrystalline ingot capable of stably producing a large-sized ingot having a homogeneous structure and high strength.

[0008]

According to the present invention, there is provided a high-frequency induction electrolytic furnace (12) having a hollow crucible (12a) having an open lower part, and an ingot case (10) located below the electrolytic furnace and having an open upper part. 14) and a throat (1) that hermetically communicates the lower opening of the crucible with the upper opening of the ingot case.
6) and refined material with adjusted components (10)
A throat closing step S1 for forming a plug (11) for closing the inside of the throat, a material sealing step S2 for sealing the material in the electrolytic furnace, and a vacuum exhausting step S3 for evacuating the inside of the electrolytic furnace and the ingot case. A material melting step S4 for melting the material in the electrolytic furnace by high-frequency induction heating, a plug melting step S5 for melting the plug in the throat by high-frequency induction heating, and an ingot case through a throat for the material vacuum-melted in the electrolytic furnace. A rapid solidification step S6 of dropping into the inside and rapidly solidifying to microcrystallize, thereby producing a microcrystalline ingot.

According to a preferred embodiment of the present invention, the melting in the material melting step S4 is a levitation melting in which the active alloy can be melted without mixing impurities and a high melting point metal.

According to the present invention, there is provided a high-frequency induction electrolytic furnace (1) having a hollow crucible (12a) having an open bottom.
2), an ingot case (14) located below the electrolytic furnace and having an open top, and a throat (16) that hermetically communicates the lower opening of the crucible and the upper opening of the ingot case, and the crucible (12a). , The ingot case and the throat are made of water-cooled copper,
2) has a first high-frequency coil (12b) suitable for levitation melting around the crucible, and the throat (1)
6) A device for producing a microcrystalline ingot, comprising a second high-frequency coil (17) capable of high-frequency induction heating of the inside around 6).

According to the method and apparatus of the present invention, the hollow high-frequency induction electrolytic furnace (12) has a crucible (12a) in a crucible (12a).
The material (10) refined by adjusting the components is sealed in a vacuum state, and this is so-called levitation melting using a first high-frequency coil (12b). Since it can be melted in a floating state, the contamination of impurities can be greatly reduced and the high melting point alloy can be melted. Further, the throat (16) is closed with a plug (11) made of a material (10), and this is closed with a second high-frequency coil (1).
The material melted in step 7) and vacuum-melted in the electrolytic furnace can be dropped into the ingot case through the throat,
At this time, since the temperature of the hot water flowing out of the second high-frequency coil (17) is controlled to control the dripping flow rate and to rapidly solidify the molten metal little by little, segregation at the time of condensing the molten metal and coarsening of particles are effectively suppressed. This makes it possible to stably produce a large ingot having a uniform and high strength as a whole.

A coil (18) for applying a horizontal force to the molten material dropped around the ingot case (14), and an ultrasonic vibrator for vibrating the molten material in the ingot case (14). (19). With this configuration, in addition to controlling the temperature of the hot water flowing out of the second high-frequency coil (17) to control the flow rate of the dripping, a horizontal force acts on the molten material dripped by the magnetic field generated by the coil (18). By moving the position of the molten metal to be dropped, the depth of the molten metal pool in the ingot case can be made uniform. Further, in order to obtain fine crystals, preferably, the molten metal is vibrated by a plurality of ultrasonic vibrators (19) to prevent the crystals from being coarsened during solidification, thereby obtaining uniform and fine crystals.

In order to rapidly solidify and obtain an ingot of fine crystals, it is preferable to control the temperature of the molten metal to be slightly higher than the solidifying temperature and to control the molten metal pool as shallow as possible. In addition, if necessary, an inert gas (such as He gas) may be introduced into the ingot case to make it an inert atmosphere.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of so-called Levitation dissolution.
As shown in this figure, the levitation dissolution was performed in the crucible 2
A high-frequency coil 3 is provided around the periphery to melt the material by high-frequency induction heating. In this case, by using a water-cooled copper crucible for the crucible 2, peeling or falling off of the crucible can be avoided. Further, since the molten metal 1 is heated while being swung while being floated from the inner surface of the crucible 2 by magnetic pressure due to high frequency induction, the entire molten metal can be homogenized, and the high melting point metal can be melted without mixing impurities. is there. In addition,
As shown in this figure, since the lower part of the molten metal 1 comes into contact with the crucible 2 by its own weight, a solidified shell 4 called a skull is formed in this part.

FIG. 2 is a block diagram of the apparatus for producing a microcrystalline ingot of the present invention. As shown in this figure, the apparatus for manufacturing a microcrystalline ingot of the present invention includes a high-frequency induction electrolytic furnace 12 having a hollow crucible 12a, an ingot case 14, and a throat 16.

The crucible 12a, the ingot case 14, and the throat 16 of the high-frequency induction electrolytic furnace 12 are made of water-cooled copper cooled by cooling water (not shown) in order to avoid peeling or falling off as impurities. The crucible 12a is open at least below. The opening portion is preferably formed in a funnel shape so that the molten metal melted from the opening inside can be easily dropped downward. Further, the high-frequency induction electrolytic furnace 12 has a first high-frequency coil 12b suitable for the above-mentioned levitation melting around the crucible 12a, and a high-frequency current is supplied to the first high-frequency coil 12b from a power supply device (not shown). The internal molten metal 10a can be heated while being rocked by the magnetic pressure generated by high-frequency induction while being floated from the inner surface of the crucible 12a.

The ingot case 14 is located below the electrolytic furnace 12 and has at least an upper opening, and receives the molten metal from the opening. The ingot case 14 preferably has a hollow cylindrical shape or a shape in which the upper portion is slightly widened so that the ingot after solidification can be easily taken out.

In this example, in the ingot case 14
Is provided with a coil 18 for applying a horizontal force to the molten material to be dropped. The coil 18 changes the magnetic pressure in the levitation melting from side to side and back and forth, and applies a horizontal force to the molten metal 10a to be dropped by the magnetic field to move the dropping position, so that the depth of the molten pool in the ingot case is reduced. Is made uniform.

Further, around the ingot case 14, a plurality of ultrasonic vibrators 19 are attached at arbitrary positions to vibrate the molten metal 10a in the ingot case to prevent the crystal from being coarsened at the time of solidification. To obtain homogeneous and fine crystals.

The throat 16 hermetically communicates the lower opening of the crucible 12a and the upper opening of the ingot case 14.
A second high-frequency coil 17 capable of high-frequency induction heating is provided around the throat 16, and the throat 16 is closed with a plug 11 made of the material 10. 10a melted in a vacuum
Is dropped through the throat 16 into the ingot case 14.

FIG. 3 is a diagram for explaining the operation of FIG.
FIG. 1 is a flowchart showing a method for producing a microcrystalline ingot of the present invention. The method of the present invention will be described below with reference to FIGS.

In step S0, first, a refined material 10 is prepared by adjusting its components. This preparation is performed in the same manner as the conventional ingot production, as in the case of the high-speed induction melting furnace (Vacu).
umInduction Melting & Cas
ting), vacuum casting (Vacuum Castin)
g), vacuum arc remelting furnace (ConsumableEl)
electron Vacuum Arc Furnac
e), electroslab remelting furnace (Electro R)
emulating Furnace) or the like. In this case, instead of casting an ingot of the size required for the target large part as a single piece, cast it as small as possible to reduce the segregation and coarsening of the high melting point alloy containing aluminum, titanium, tungsten, molybdenum, etc. It is best to minimize it. Next, the cast material is crushed and pulverized to be used as the material 10.

Next, in a throat closing step S1, a plug 11 for closing the inside of the throat 16 is manufactured using the raw material 10, and this is used to form the plug 11 as shown in FIG.
Block the inside of 6. For manufacturing the plug 11, for example, a HIP device can be used using only the raw material 10 as a raw material.

Next, in a material sealing step S2,
The raw material 10 is sealed in the crucible 12a of the electrolytic furnace 12, and in the evacuation step S3, the crucible 12a of the electrolytic furnace 12
The inside and the ingot case 14 are evacuated by a vacuum device (not shown). At this time, if necessary, an inert gas (such as He gas) may be introduced into the ingot case to form an inert atmosphere.

Next, as shown in FIG. 3B, in a material melting step S4, the material 10 in the electrolytic furnace 12 is melted by high-frequency induction heating. This melting is preferably a levitating melting in which the active alloy can be dissolved without mixing impurities. Next, in a plug melting step S5, the plug 11 in the throat 16 is melted by high-frequency induction heating, and then in a rapid solidification step S6, the molten metal 10a melted in vacuum in the electrolytic furnace 12 is dropped into the ingot case 14 through the throat 16 and rapidly. Solidifies and microcrystallizes.

In order to rapidly solidify and obtain an ingot of fine crystals, the temperature of the molten metal is controlled to be slightly higher than the solidification temperature, and the molten metal pool is controlled to be as shallow as possible.

According to the method and apparatus of the present invention described above,
In a crucible 12a of a hollow high-frequency induction electrolysis furnace 12, a material 10 whose components have been adjusted and refined is sealed in a vacuum state, and this is subjected to water-cooled copper electrolysis by so-called levitation melting using a first high-frequency coil 12b. Since the metal can be melted in a state of being floated from the furnace wall by magnetic pressure in the furnace, the mixing of impurities can be greatly reduced and the high melting point alloy can be melted.

Further, the throat 16 is closed with the stopper 11 made of the material 10, which is melted by the second high-frequency coil 17, and the molten metal 10 a melted in a vacuum in the electrolytic furnace is dropped into the ingot case 14 through the throat 16. Can be. Further, at this time, since the temperature of the molten metal 10a flowing out of the second high-frequency coil 17 is controlled to control the dripping flow rate and to rapidly solidify the molten metal little by little, it is possible to effectively suppress segregation and coarsening of particles during the condensation of the molten metal. This makes it possible to stably produce a large ingot having a uniform and high strength as a whole.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0030]

As described above, the method and apparatus for manufacturing a microcrystalline ingot according to the present invention can greatly reduce the mixing of impurities and can melt a high melting point alloy, and can segregate the molten metal during condensation. In addition, the present invention has an excellent effect that a large ingot having a uniform and high strength as a whole can be stably manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of levitation dissolution.

FIG. 2 is a configuration diagram of an apparatus for producing a microcrystalline ingot of the present invention.

FIG. 3 is an operation explanatory view of FIG. 2;

FIG. 4 is a flowchart showing a method for producing a microcrystalline ingot of the present invention.

[Explanation of symbols]

1 molten metal, 2 water-cooled copper crucible, 3 high-frequency coil, 4
Solidified shell, 10 material, 10a molten metal, 11 stopper, 1
2 High frequency induction electrolytic furnace, 12a crucible, 12b first
High frequency coil, 14 ingot case, 16 throat, 17 second high frequency coil, 18 coil, 19 ultrasonic vibrator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22B 9/04 C22B 9/04 9/22 9/22 F27B 14/04 F27B 14/04 14/06 14 / 06 14/14 14/14 14/18 14/18 F27D 3/14 F27D 3/14 B 7/06 7/06 A 11/06 11/06 A F term (reference) 4K001 AA02 AA17 AA27 AA29 EA02 FA14 GA17 4K046 AA01 BA03 CC01 CD02 CD11 CE08 4K055 AA04 JA13 4K063 AA03 AA04 AA12 AA16 BA03 CA03 DA19 FA34

Claims (4)

[Claims] 1. A hollow crucible (12a) having an open bottom.
A high-frequency induction electrolysis furnace (12), an ingot case (14) located below the electrolysis furnace and having an open top, and a throat (16) that hermetically communicates the lower opening of the crucible and the upper opening of the ingot case. A throat closing step S comprising a plug (11) for closing the throat with a material (10) refined by adjusting the components.
1, a material sealing step S2 for sealing the material in the electrolytic furnace, a vacuum evacuation step S3 for evacuating the inside of the electrolytic furnace and the ingot case, and a material melting for melting the material in the electrolytic furnace by high-frequency induction heating Step S4, a plug melting step S5 for melting the plug in the throat by high-frequency induction heating, and a rapid solidification step S6 for dropping the material vacuum-melted in the electrolytic furnace into the ingot case through the throat to rapidly solidify and microcrystallize. A method for producing a microcrystalline ingot, comprising: 2. The microcrystalline ingot according to claim 1, wherein the melting in the material melting step S4 is levitation melting in which an active alloy can be melted without mixing impurities and a high melting point metal. Production method. 3. A hollow crucible (12a) having an open bottom.
A high-frequency induction electrolysis furnace (12), an ingot case (14) located below the electrolysis furnace and having an open top, and a throat (16) that hermetically communicates the lower opening of the crucible and the upper opening of the ingot case. The crucible (12a), the ingot case and the throat are made of water-cooled copper, and the high-frequency induction electrolytic furnace (12) is provided around the crucible with a first high-frequency coil (12b) suitable for levitation melting.
And a second high-frequency coil (17) capable of high-frequency induction heating of the inside around the throat (16). 4. A coil (18) for applying a horizontal force to the molten material dropped around the ingot case (14), and an ultrasonic vibrator for vibrating the molten material in the ingot case (14). The apparatus for producing a microcrystalline ingot according to claim 3, comprising (19).