JP2000292070A - Metal material melting and tapping method and apparatus - Google Patents

Abstract

(57) [Abstract] [Problem] It is possible to shorten the time required to discharge molten metal in a furnace,
In addition, a method and an apparatus for melting and discharging a metal material capable of stably discharging a fixed amount of molten metal in a furnace are provided. An upper end of a plug closing a tap hole at the bottom of a furnace is projected into the furnace when a metal material is melted using a levitation furnace, and a solidification shell at the bottom of the furnace is hollow inside the furnace to cover the top of the tap port. A solidified shell portion raised in a shape was formed.

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 melting a metal material. After melting the metal material in a floating state by high frequency induction heating using a levitation furnace,
The molten metal is discharged from a tap hole of the levitation furnace, and casting or gas pulverization is performed. The present invention relates to a method for dissolving a metal material and an improvement in an apparatus used for the method.

[0002]

2. Description of the Related Art Conventionally, various methods and apparatuses for dissolving a metal material as described above have been proposed (Japanese Unexamined Patent Publication No.
-107404, JP-A-4-100669, JP-A-10-100
-318679). Some of these conventional means continuously dissolve the molten metal material, and others perform it in batches. In order to perform the melting and tapping of the metal material in a batch manner, the furnace body of the levitation furnace is composed of a water-cooled copper crucible and a bottom block, and the bottom block is provided with a tap at the center thereof. There has been proposed a taphole which is provided with a plug which can be attached to and detached from a taphole so as to be able to move forward and backward (Japanese Patent Laid-Open No. 10-318679).

[0003] In the above-mentioned conventional means for dissolving and discharging a metal material in a batch manner, the metal material is melted and discharged as described below. First, the metal material put into the furnace is melted in a suspended state by high-frequency induction heating. At the time of such melting, the tap hole is, of course, closed with a plug, but since there is heat conduction in a portion that comes into contact with the hearth block and the plug, a portion that comes into contact with the hearth block and the plug at the hearth. Forms a solidified shell. The molten metal in the furnace is floating in an oval shape on the solidified shell at the bottom of the furnace. Therefore, even if the plug is removed from the tap after melting, the top of the tap is covered with the solidified shell, so that the molten metal in the furnace does not immediately flow down from the tap. Then, next, after removing the plug from the tap hole, the inside of the furnace is continuously subjected to high-frequency induction heating. Due to this heating, the solidified shell portion covering the upper part of the tap hole no longer conducts heat to the plug that was in contact therewith, so it was re-melted, and the inside of the furnace and the tap hole were connected, and the inside of the furnace The molten metal flows down from the tap.

[0004] However, in the conventional means as described above, after the plug is removed from the tap hole, it is time-consuming to continuously heat the inside of the furnace with high-frequency induction to re-melt the solidified shell portion covering the tap hole. There is a problem that it takes. In the conventional means, the tap hole is closed with a plug at the time of melting, but when the plug is closed, the upper surface of the tap member is located lower than around the upper end portion of the tap hole. A solidified shell having a shape roughly like an egg shell divided in half and having a slightly thicker portion covering the tap hole is formed. In the solidified shell having such a shape, it takes time to re-dissolve the solidified shell portion covering the tap hole by high-frequency induction heating.

[0005]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is that the conventional means for batch-wise melting and tapping of a metal material using a levitation furnace requires a solidified shell formed at the furnace bottom during melting. It is a point that it takes a long time to discharge molten metal in the furnace because the shape is defective.

[0006]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems is to melt a metal material in a floating state by high frequency induction heating using a levitation furnace, and then to melt the molten metal at the outlet of the levitation furnace. In the method of tapping, the upper end of the plug that closes the tap hole provided at the center of the furnace bottom of the levitation furnace at the time of melting is made to project into the furnace so that the upper end of the plug is placed on the furnace bottom. By forming a solidified shell raised in the above, the inside of the furnace is continuously heated at a high frequency while the plug is removed at the time of tapping, so that the solidified shell portion which is raised in a hollow shape inside the furnace covering the upper part of the taphole is formed. The present invention relates to a method for melting and tapping a metal material, characterized by re-melting to make the tap hole communicate with the inside of the furnace and discharging the molten metal in the furnace from the tap port.

[0007] The present invention also provides an apparatus in which a metal material is melted in a suspended state by high frequency induction heating using a revitating furnace, and then the molten metal is discharged from a tap hole of the revitating furnace. The furnace body of the furnace is composed of a water-cooled copper crucible and a hearth block, and the hearth block has a tap hole at the center thereof, and a water-cooled copper plug that can be attached to and detached from the tap hole can be moved forward and backward. When the copper plug body is advanced to close the tap hole, the upper end of the copper plug body projects into the furnace, and the copper plug body is advanced on the furnace bottom block during melting. A solidified shell is formed at the upper end of the plug body, and at the time of tapping, the inside of the furnace is continuously heated at a high frequency while the copper plug body is retracted, thereby forming a hollow inside the furnace covering the top of the tap hole. Excitement Solid shell redissolved by communicating the said output sprue and furnace and according to the dissolution tapping device for a metallic material characterized by comprising as to tapping the molten metal in the furnace from said output sprue.

[0008] In the method for melting and tapping a metal material according to the present invention, the metal material is melted in a suspended state by high frequency induction heating using a revitating furnace, and then the molten metal is discharged from the tap of the revitating furnace. A levitation furnace itself for melting a metal material in a floating state by high-frequency induction heating is already well known, but in the levitation furnace used in the present invention, a tap hole is provided at the center of the furnace bottom. A plug is detachably mounted on the tap hole, and the furnace bottom including the tap port is generally formed in a generally funnel shape as a whole.

In the method for melting and tapping a metal material according to the present invention, when the metal material is melted, the upper end of a plug that closes a tap hole provided at the center of the furnace bottom of the levitation furnace is projected into the furnace. And keep it. During melting, there is heat conduction between the block that forms the furnace bottom and the part that comes in contact with the plug that closes the tap hole provided at the center of this block, so a solidified shell is formed at these parts on the furnace bottom. However, although this solidified shell usually has a shape almost half of an egg shell, the upper end of the plug that closes the tap hole protrudes into the furnace at the central portion directly below the tap hole. As a result, the shape rises to the inside of the furnace.

In the method for melting and tapping a metal material according to the present invention, a solidified shell having the above-described shape is formed on the furnace bottom during melting, and the furnace is continuously removed from the molten metal with the plug removed. High frequency induction heating inside. By this heating, the solidified shell portion which has risen in a hollow shape inside the furnace covering the upper part of the tap hole is redissolved to make the tap hole communicate with the inside of the furnace, and the molten metal in the furnace is discharged from the tap hole. If the inside of the furnace is continuously heated by high-frequency induction heating with the plug removed, the solidified shell that covers the tap hole at the center of the furnace bottom is re-melted because there is no heat conduction to the plug that was in contact with it anymore. However, instead of simply re-melting, the part of the solidified shell formed on the furnace bottom that covers the upper part of the tap hole is preferential because its thickness is thin in addition to the hollow bulging inside the furnace. , And the inside of the furnace can be communicated in a short time. Moreover, in this case, since the solidified shell portion covering the upper part of the tap hole is re-dissolved in approximately the same size as the tap hole, the molten metal in the furnace can be discharged at a constant rate from the beginning.

In the method for dispensing a molten metal material according to the present invention, a casting mold is provided below the tapping hole, and the molten metal is poured into the casting mold, and the molten metal can be cast simultaneously with the molten metal. . Further, a gas injection nozzle may be provided facing the molten metal flowing down from the outlet, and, for example, argon gas may be injected from the gas injection nozzle into the molten metal in the middle of flowing, so that the gas can be pulverized simultaneously with the molten metal.

The metal material melting and tapping apparatus according to the present invention comprises:
This is an apparatus used for the metal material melting and tapping method according to the present invention as described above. In the metal material melting and tapping apparatus according to the present invention, the furnace body of the levitation furnace includes a water-cooled copper crucible and a furnace bottom block. The furnace bottom block in this case is preferably made of graphite, copper, water-cooled copper, water-cooled stainless steel, or the like, which has good heat resistance and heat conductivity, and is provided in the center on the upper surface thereof. It is preferable that an inclined surface descending toward the tap is formed. A tap hole is provided at the center of the hearth block, and the tap hole is provided with a water-cooled copper plug that can be attached to and detached from the tap hole so that the copper plug can move forward and backward to close the tap hole. The upper end protrudes into the furnace.

Therefore, as described above, when the metal material is melted, the solidified shell raised at the upper end of the copper plug which is in the forward state and which is fitted to the tap hole and closing it is placed on the furnace bottom block. In addition, at the time of tapping of the molten metal, the solidification shell portion which has been raised in a hollow shape to the inside of the furnace covering the upper part of the tap hole is continuously heated by inductively heating the inside of the furnace in a state where the copper plug is retracted. The molten metal in the furnace is discharged from the molten metal outlet through the molten metal outlet, and the molten metal in the furnace is discharged from the molten metal outlet.

The tap hole is preferably formed at the center of the furnace bottom block, with a tap nozzle attached to the opening and formed inside the tap nozzle. In this case, the tap nozzle is made of alumina. Zirconia, yttria,
It is preferable to use one made of magnesia or the like having good heat resistance. In addition, it is preferable that the copper plug body has an inclined surface having a side peripheral surface around the upper end portion gradually narrowing toward the upper end. A solidification shell formed around the upper end of the copper plug and thus solidified in a hollow shape inside the furnace covering the upper part of the tap, while smoothly attaching and detaching the copper plug to and from the tap hole. This is for making the shell portion easily re-meltable by high-frequency induction heating.

[0015] In the metal material melting and tapping apparatus according to the present invention, a casting mold is provided so as to be able to advance and retreat under the tapping port.
The molten metal that has been poured can be poured into the mold that has been advanced immediately below the molten metal, and the molten metal can be cast simultaneously with the molten metal. Also, a gas injection nozzle may be provided facing the molten metal flowing down from the outlet, and, for example, argon gas may be injected from the gas injection nozzle into the molten metal in the middle of flowing, and the gas may be pulverized at the same time as the molten metal is discharged. it can.

The method and apparatus for melting and discharging a metal material according to the present invention do not particularly limit the type of metal material to be melted and melted by these methods. Yes, it is particularly suitable when applied to an alloy of titanium or an alloy thereof, such as titanium and zirconium, molybdenum, niobium, tantalum, chromium, vanadium, aluminum, nickel and copper.

[0017]

FIG. 1 is a longitudinal sectional view illustrating a metal material melting and tapping apparatus according to the present invention. The furnace body 12 of the levitation furnace 11 includes a copper crucible 21 composed of a plurality of segments arranged in a cylindrical shape as a whole in the axial direction.
And a furnace bottom block 31 made of graphite, whose hollow portion faces downward and is inserted into an inner peripheral inclined surface formed to have a narrow width in order. An insulation tube 13 made of bakelite is attached to the outer peripheral surface of the copper crucible 21, and a coil 14 is provided on the outer periphery thereof. The water-cooled crucible 21 is supported by upper and lower magnetic seal plates 15 and 16, and a furnace lid 18 having a viewing window 17 is attached to the upper magnetic seal plate 15 so as to be able to advance and retreat. Copper crucible 21 and magnetic seal plate 1
5 and 16 are water-cooled, and are made of copper crucible 2
1. Furnace bottom block 31, magnetic seal plate 15, and furnace lid 18
Argon gas is supplied to the furnace space surrounded by.

FIG. 2 is a partially enlarged view of FIG. On the upper surface of the hearth block 31, an inclined surface 32 descending toward the center.
Is formed, and an opening 33 is provided in the center thereof. The opening 33 is formed to be narrower in the downward direction, and a zirconia tapping nozzle 34 is fitted into the opening 33. Therefore, tap hole 35 is provided with tap nozzle 3
4 are formed inside.

Below the copper crucible 21, a casting chamber 42 is connected via a connecting member 41. A transfer roller 43 is laid in the casting chamber 42.
A mold 44 is placed on the top so as to be able to advance and retreat. Casting room 42
The inside is supplied with argon gas, and the mold 44 is water-cooled.

The tapping hole 35 formed inside the tapping nozzle 34 faces directly above, and penetrates the casting chamber 42 to form a copper plug 51.
Is equipped. The copper plug 51 is attached to the reciprocating means 52, and reciprocates (in the case of FIGS. 1 and 2) by the reciprocating means 52, and is water-cooled. When the copper plug 51 is advanced, its upper outer peripheral surface is slidably fitted on the inner peripheral surface of the tapping nozzle 34 to close the tap hole 35, and at the time of retreat, its upper portion is located at the lower portion of the casting chamber 42. Has become. The copper stopper 51 is connected to the upper end 5 thereof.
The side peripheral surface of No. 2 is an inclined surface that gradually narrows upward and the upper end portion 52 projects into the furnace during the above-described forward movement.

In the device described above with reference to FIGS. 1 and 2,
Dissolve the metal material and tap as follows. First, the copper plug 51 is advanced to close the tap hole 35 and the upper end 52 thereof is projected into the furnace.
Cooling water is flowed through 5, 16 and the copper plug 51 to be water-cooled.
Then, the furnace cover 18 is retracted and opened, and after the metal material is charged into the furnace, the furnace cover 18 is advanced and closed, and the inside of the furnace is brought into an argon gas atmosphere. In this state, a high-frequency current is applied to the coil 14 to heat the metal material in the furnace by high-frequency induction. By this heating, the metal material is dissolved in a floating state. In the furnace, the molten metal 61 in a state of being floated in an oval shape is generated by Lorentz repulsion, which is already well known in a levitation furnace. And the hearth block 3
1 and at the portion contacting the upper end of the copper plug 51, and consequently at the portion contacting the copper crucible 21;
1 is formed. Although the solidified shell 71 generally has a shape that is roughly a half of an eggshell, the solidified shell that rises to the inside of the furnace because the upper end 52 of the copper plug 51 protrudes into the furnace at the center thereof. A portion 72 is formed. FIGS. 1 and 2 show the state of formation of the molten metal 61 and the solidified shell 71 as described above when the metal material is melted.
In addition, the state of formation of the solidified shell 72 is shown.

After the metal material is melted in a floating state by high-frequency induction heating, when the molten metal 61 generated in the furnace is discharged, the copper plug 51 is first retracted. FIG. 3 is a partially enlarged view showing a state where the copper stopper 51 is retracted corresponding to FIG. When the copper plug 51 is retracted, a solidified shell portion 72 that rises in a hollow shape inside the furnace that covers the upper part of the tap hole 35 remains at the center of the solidified shell 71. In this state, the mold 44 cooled with water in the casting chamber 42 previously set in an argon gas atmosphere is advanced to a position immediately below the tap hole 35, and the inside of the furnace is subsequently subjected to high-frequency induction heating. By this heating, among the solidified shells 71 formed on the furnace bottom, the solidified shell portion 72 that has been hollowed up inside the furnace covering the upper part of the tap hole 35 is preferentially melted in a short time. FIG. 4 is a partially enlarged view corresponding to FIG. 3, showing a state in which the solidified shell portion 72 has been redissolved. When the solidified shell portion 72 is remelted, the inside of the furnace and the tap hole 35 communicate with each other, and the molten metal 61 in the furnace flows down from the tap port 35 to the mold 44 and is cast into a predetermined shape.

FIG. 5 is a longitudinal sectional view illustrating another apparatus for melting and discharging a metal material according to the present invention. In the apparatus shown in FIG. 5, the other configurations, operations, and the like, the description of which is omitted, are the same as those of the apparatus described above with reference to FIGS. For convenience, similar constituent members are indicated by the same symbols as in FIG. In the apparatus shown in FIG. 5, a recovery chamber 46 is connected to a lower portion of the copper crucible 21a via a longer connecting member 45. A transfer roller 43a is laid in the collection chamber 46, and a receiver 47 is mounted on the transfer roller 43a so as to be able to advance and retreat. Gas injection nozzles 81 and 82 are provided diagonally downward above the connection member 45 so as to face the molten metal 61a flowing down from the tap hole.
Argon gas is injected from the gas injection nozzles 81 and 82 to pulverize the gas, and the pulverized material is advanced immediately below the receiver 47.
Is to be collected.

[0024]

As is clear from the above, according to the present invention described above, the time required for the molten metal in the furnace to be discharged can be reduced.
In addition, there is an effect that a fixed amount of molten metal in the furnace can be stably discharged.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating a metal material melting and tapping apparatus according to the present invention.

FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3 is a partially enlarged view showing a state in which the copper stopper is retracted corresponding to FIG. 2;

FIG. 4 is a partially enlarged view showing a state in which a solidified shell portion is redissolved corresponding to FIG. 3;

FIG. 5 is a vertical cross-sectional view illustrating an apparatus for melting and tapping another metal material according to the present invention.

[Explanation of symbols]

14, 14a coil, 21, 21a copper crucible, 31, 31a hearth block, 34, 34a
Hot water nozzle, 35 hot water outlet, 41, 45 connection member, 44 mold, 47 receiver, 51, 51a copper plug, 52, 52a top end, 71, 71a Solidified shell, 72, 72a ··· Solidified shell part, 81, 82
..Gas injection nozzles

Claims (8)

[Claims] 1. A method of melting a metal material in a floating state by high frequency induction heating using a levitation furnace, and then tapping the molten metal from a tap hole of the levitation furnace. By setting the upper end of the plug that closes the tap hole provided at the center to project into the furnace, a solidified shell that rises at the upper end of the plug is formed at the bottom of the furnace. By removing the furnace with high frequency induction heating inside the furnace,
Re-melt the solidified shell portion that has risen to the inside of the furnace covering the upper part of the tap hole to allow the tap hole to communicate with the inside of the furnace,
A method for melting and tapping a metal material, wherein the molten metal in the furnace is discharged from the tap. 2. A mold is provided below the water outlet, facing downward.
2. The method according to claim 1, wherein the molten metal is poured into the mold, and the molten metal is cast simultaneously with the molten metal. 3. A gas injection nozzle is provided facing the molten metal flowing down from the outlet, and a gas is injected from the gas injection nozzle to the molten metal in the middle of flowing, and the gas is pulverized simultaneously with the molten metal being discharged. A method for dissolving a metal material according to the above description. 4. An apparatus in which a metal material is melted in a suspended state by high-frequency induction heating using a levitation furnace, and the molten metal is discharged from a tap hole of the levitation furnace. The main body is composed of a water-cooled copper crucible and a hearth block, and the hearth block is provided with a tap at the center thereof, and the tap is equipped with a water-cooled copper plug that can be attached to and detached from the tap. When the copper plug is advanced to close the tap hole, the upper end of the copper plug protrudes into the furnace, and when the copper plug is melted, the copper plug is advanced on the furnace bottom block. A raised solidified shell was formed at the upper end, and at the time of tapping, the inside of the furnace was continuously subjected to high-frequency induction heating in a state where the copper plug was retracted, so that the inside of the furnace covering the top of the tap hole was raised in a hollow shape. Solidification shell A melting and tapping apparatus for a metal material, characterized in that the metal is re-melted to allow the tap hole to communicate with the inside of the furnace, and the molten metal in the furnace is discharged from the tap port. 5. The melting and tapping apparatus for a metal material according to claim 4, wherein an opening is provided in a central portion of the furnace bottom block, and a tapping nozzle is attached to the opening, and a tapping hole is formed on the inside surrounded by the tapping nozzle. 6. The molten metal tapping apparatus according to claim 4, wherein the peripheral surface around the upper end of the copper plug is formed as an inclined surface having a width gradually decreasing toward the upper end. 7. The mold is provided so as to be able to advance and retreat under the tap hole, and the poured molten metal is poured into the mold so that the molten metal is cast simultaneously with the molten metal.
7. An apparatus for dispensing and dissolving a metal material according to 5 or 6. 8. A gas injection nozzle is provided facing the molten metal flowing down from the outlet, and a gas is injected from the gas injection nozzle to the molten metal in the middle of flowing, so that the gas is pulverized at the same time as the molten metal is discharged. 7. The molten metal tapping apparatus according to claim 4, 5 or 6.