JPH05192752A - Holding furnace in dfp casting apparatus - Google Patents

Abstract

PURPOSE:To improve the quality of a product by holding a space between a cover part of a molten copper supplying chamber and the upper part of molten copper in vacuum with a vacuum pump directly connected with the upper cover part of the molten copper supplying chamber, in a DFP casting apparatus. CONSTITUTION:In the DFP casting apparatus having a holding furnace 1 for providing a molten copper holding chamber composed of a molten copper introducing chamber and the molten copper supplying chamber 5 and for keeping the molten state by an inductor 17 and a crucible for temporarily storing the molten copper supplied from the molten copper supplying chamber in the holding furnace 1 and for manufacturing a casting rod by passing a core rod wire in the molten copper from the lower toward the upper part, the vacuum pump 11 is directly connected with the upper cover parts 6, 8 in the molten copper supplying chamber 5 and the hydrogen gas in the molten copper 5 is removed by holding the air in between the cover parts 6, 8 in the molten copper supplying chamber 5 and the upper end part of the molten copper 4 to the vacuum state. By this method, the development of pin hole into columnar structure in the casting rod can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DFP casting apparatus for continuously producing a copper rough drawn wire from molten copper in one step, and more particularly to a DFP casting apparatus capable of removing hydrogen gas contained in molten copper.
The present invention relates to a holding furnace of an FP casting device.

[0002]

2. Description of the Related Art As conductors for insulated wires and cables,
In the production of copper (copper alloy) wires and copper (copper alloy) twisted wires used as communication wires or transmission / distribution wires, in general, a rough drawn wire is manufactured, and this rough drawn wire is formed into a desired wire diameter in a drawing process. It is manufactured by wire drawing. There are a bar copper hot rolling method and a continuous casting and rolling method in the method of manufacturing the wire drawing wire. The continuous casting and rolling method includes an SCR method and a dip forming process (Dip Forming Process). Due to the requirement of conductivity, by moving the base metal above the bottom of the crucible containing electrolytic copper obtained by melting in a reducing atmosphere, the molten copper is attached to the surroundings to obtain a bare wire of oxygen-free copper.・ Forming method (DF
The dip molding device (DFP casting device) according to P) is often used.

This DFP casting machine (immersion molding machine)
It has a system configuration as shown in FIG. That is,
100 is a DFP casting apparatus, and 110 is a preheating furnace. This preheating furnace 110 is supplied with electrolytic copper 120.
Is preheated to a predetermined temperature. A melting furnace 130 melts the electric copper 120 heated to a predetermined temperature in the preheating furnace 110.

Reference numeral 140 denotes a holding furnace for holding the electrolytic copper 120 melted in the melting furnace 130 in a temporarily molten state. Reference numeral 150 denotes a crucible, which is supplied with the electric copper 120 quantitatively from the holding furnace 140. The holding furnace 140 and the crucible 150 have a structure as shown in FIG. That is, the holding furnace 140 is a molten copper introduction chamber (not shown) in which the electrolytic copper 120 melted in the melting furnace 130 is introduced and temporarily held.
A molten copper pressurizing chamber 141 that is partitioned by the molten copper introducing chamber and the partition plate 142 and is provided adjacent to the molten copper introducing chamber to press the molten copper at a constant pressure to send the molten copper; Chamber 141
The upper part is partitioned by the partition plate 142 and the molten copper pressure chamber 1
41 and a molten copper pressure chamber 141 provided adjacent to the molten copper introduction chamber
And a molten copper supply chamber 143 that quantitatively supplies the melted electrolytic copper 120 sent by the pressurization to the crucible 150.

Although not shown, the molten copper introducing chamber is provided on its side wall with an introducing pipe through which the electrolytic copper 120 melted from the melting furnace 130 is introduced. 144 is a molten copper pressure chamber 14
1 is a lid attached to the upper part of 145, and 145 is a lid 144
It is a gas supply port formed in. This gas supply port 145
Is supplied with an inert gas (specifically, nitrogen gas) into the molten copper pressurizing chamber 141 at a predetermined pressure to push down the molten copper surface, so that the molten electric power in the molten copper pressurizing chamber 141 is melted. It is for supplying the copper 120 to the molten copper supply chamber 143 through the lower side of the partition plate 142.

Reference numeral 146 is a lid, which is attached to the upper portion of the molten copper supply chamber 143. Further, reference numeral 147 is a supply pipe, and the molten electrolytic copper 12 in the molten copper supply chamber 143 is placed in the crucible 150.
This is for quantitatively supplying 0. Reference numeral 148 is an inductor for holding the molten electrolytic copper 120 supplied from the melting furnace 130 in the holding furnace 140 in a molten state.

The crucible 150 constitutes a container for holding a certain amount of molten copper supplied from the molten copper supply chamber 143 of the holding furnace 140, and the core rod wire 16 is contained in the contained molten copper.
0 from the bottom to the top to allow the core rod wire 16
Oxygen-free copper casting rod 170 with molten copper attached around 0
Is manufactured. That is, the crucible 150 has an opening formed at the lower end, and the nozzle is fitted in this opening. The core rod wire 160 is configured to pass through this nozzle. Then, in the crucible 150, a holding furnace 140 is provided so that the molten copper always keeps a constant amount.
It is configured to be replenished via.

Reference numeral 180 is a main drive, which is a crucible 150.
It is for driving the core rod wire 160 fed into the. 190 is a shaving head, which is a crucible 150.
It is for removing oxides on the surface of the core rod wire 160 fed into the. 200 is a cooling device, which is a crucible 150.
For cooling the cast rod 170 obtained by depositing molten copper around the core rod wire 160. 210
Is a bull block for guiding the core rod wire 160 from the seed wire storage device 220 holding the core rod wire 160. Further, 230 is a rolling mill, which is a casting rod 1
It is for rolling 70 to extend it to a desired wire diameter.

Since the core rod wire 160 is constructed as described above, the core rod wire 160 is separated from the seed wire storage device 220.
It is fed to the shaving head 190 via a bull block 210 that guides 60. In this shaving head 190, the oxide on the surface of the core rod wire 160 serving as a seed wire is removed by a shaving die.

The core rod wire 160 shaving by the shaving head 190 is sent to the crucible 150 by the main drive 180. Then, the core rod wire 160 is connected to the melting furnace 13 in an inert gas atmosphere.
The molten copper is attached to the periphery by running above the bottom of the crucible 150 containing the electrolytic copper melted at 0 to obtain a cast rod of oxygen-free copper.

[0011]

As described above, since the molten copper regularly adheres to the outside of the core rod wire 160 and grows, a columnar structure is formed as shown in FIG. To solidify. At this time, even if the molten copper contains hydrogen gas of about 1.5 × 10 ⁻⁴ (wt%) or less, the amount of solid solution at the solidification temperature (1083 ° C.) of the copper makes it possible to cool the molten copper. Then, when solid-dissolved, it is solid-dissolved without any influence.

However, about 1.5 × 10 in molten copper
^If the amount of hydrogen gas exceeds ^-4 (wt%), solid solution cannot be formed at the solidification temperature of copper (1083 ° C), and when the molten copper is cooled to form a solid solution, about 1. 5 × 10 ^-4 (wt
%), Where hydrogen gas in an amount exceeding 100% remains, pinholes 250 remain in the columnar structure as shown in FIG.
In some cases, continuous holes may be formed from the inside to the outside. If a pinhole 250 is formed in the columnar structure of the cast rod during the production of this copper rough drawn wire, there is a problem that the wire may be broken if repeatedly bent.

Further, the pinhole 250 formed by the hydrogen gas remaining in the columnar structure does not disappear even if the grown copper wire to which the molten copper adheres is rolled in the next rolling step and is drawn by a rough drawing line. Appears as a blemish scratch 300 as shown in 6. If the bruise scratches 300 remain on the wire, the conductivity of the copper wire may be lowered, and if the wire is repeatedly bent, the wire may be broken.

According to the present invention, the hydrogen gas contained in the molten copper can be suppressed to a solid solution amount of about 1.5 × 10 ⁻⁴ (wt%) or less, and pinholes in the columnar structure of the cast rod can be formed. It is an object of the present invention to provide a holding furnace for a DFP casting apparatus that can prevent the occurrence of cracks and scratches when the wire is rough drawn.

[0015]

In order to achieve the above object, a holding furnace of a DFP casting apparatus of the present invention comprises a molten copper holding chamber consisting of a molten copper introducing chamber, a molten copper pressurizing chamber and a molten copper supply chamber. And a holding furnace for maintaining a molten state by an inductor, and temporarily storing molten copper supplied from a molten copper supply chamber of the holding furnace, and passing the core rod wire upward from below in the molten copper. In a DFP casting apparatus having a crucible for producing a casting rod by depressurizing, the space between the lid of the molten copper supply chamber and the upper end of the molten copper is decompressed to degas hydrogen gas in the molten copper. ..

In order to achieve the above object, the holding furnace of the DFP casting apparatus of the present invention is provided with a molten copper holding chamber including a molten copper introducing chamber, a molten copper pressurizing chamber and a molten copper supply chamber, and an inductor is used. It has a holding furnace for maintaining a molten state, temporarily holds the molten copper supplied from the molten copper supply chamber of the holding furnace, and passes the core rod wire through the molten copper from the lower side to the upper side to form a casting rod. In a DFP casting apparatus having a crucible to be manufactured, a vacuum pump is directly connected to an upper lid portion of the molten copper supply chamber to melt while maintaining a space between a lid portion of the molten copper supply chamber and an upper end portion of molten copper in a vacuum state. The hydrogen gas in copper is degassed.

It is preferable that a cooling tank is interposed between the upper lid of the molten copper supply chamber and the vacuum pump.

[0018]

The electrolytic copper melted from the melting furnace is constantly supplied to the molten copper introducing chamber, and the electrolytic copper is supplied from the molten copper introducing chamber to the molten copper pressurizing chamber in a predetermined amount. In the molten copper pressure chamber, an inert gas is regularly supplied from the gas supply port of the lid attached to the upper part, and the supply of this inert gas pushes the molten copper in the molten copper pressure chamber downward. , Is supplied to the molten copper supply chamber.

In the molten copper supply chamber, the gas in the space formed by the lid and the upper end surface of the molten copper in the molten copper supply chamber is sucked by the vacuum pump to make the space of the molten copper supply chamber in a vacuum state (5 ~ 20 TORR). By maintaining this vacuum state, the hydrogen gas contained in the molten copper in the molten copper supply chamber is degassed.

The gas discharged into the space passes through an exhaust pipe housed in a cooling tank in which a fixed amount of water is housed, is cooled, and is discharged into the atmosphere through a vacuum pump.

[0021]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows an embodiment of a holding furnace of a DFP casting apparatus according to the present invention. In the figure, 1 is a holding furnace for holding electrolytic copper melted in the melting furnace in a temporarily molten state. The holding furnace 1 includes a molten copper introduction chamber (not shown) for introducing and temporarily holding the molten electrolytic copper 120 in a melting furnace (the same as the melting furnace 130 in FIG. 2), and a molten copper. Molten copper pressurizing chamber 2 that is partitioned by the introducing chamber and the partition plate 3 and is provided adjacent to the molten copper introducing chamber to press the molten copper at a constant pressure to send out the molten copper, and the molten copper pressurizing chamber 2 and the partition The molten copper 4 which is partitioned by the plate 3 and is provided adjacent to the molten copper pressure chamber 2 and the molten copper introduction chamber and is fed out by the pressure in the molten copper pressure chamber 2
And a molten copper supply chamber 5 for quantitatively supplying the molten copper to the crucible 150.

Although not shown, the molten copper introducing chamber is provided on its side wall with an introducing pipe for introducing the electrolytic copper 120 melted from the melting furnace (same as the melting furnace 130 in FIG. 2).
Reference numeral 6 is a lid portion attached to the upper portion of the molten copper pressurizing chamber 2, and 7 is a gas supply port formed in the lid portion 6. The gas supply port 7 supplies an inert gas (specifically, nitrogen gas) into the molten copper pressurizing chamber 2 at a predetermined pressure. The inert gas supplied from the gas supply port 7 is It is for pushing down the molten copper surface in the molten copper pressure chamber 2 and supplying the molten copper 4 melted in the molten copper pressure chamber 2 to the molten copper supply chamber 5 through the lower side of the partition plate 3. ..

A lid 8 is attached to the upper portion of the molten copper supply chamber 5. An exhaust pipe 9 is for exhausting gas in a space 10 formed by the lid 8 of the molten copper supply chamber 5 and the upper end of the molten copper 4 in the molten copper supply chamber 5. Reference numeral 11 denotes a vacuum pump, which is directly connected to the exhaust pipe 9. The gas in the space 10 is extracted by the vacuum pump 11 to make a vacuum state (5 to 20 TORR). Then, the hydrogen gas contained in the molten copper 4 is discharged to the outside from the upper end surface of the molten copper 4 in the molten copper supply chamber 5. The hydrogen gas discharged to the outside is discharged to the outside of the molten copper supply chamber 5 by the vacuum pump 11 via the exhaust pipe 9.

Reference numeral 12 is a cooling tank in which a fixed amount of water 13 is stored. A certain amount of this water 13 is supplied from a water supply pipe 14 and a certain amount is discharged from a drain pipe 15. That is, the cooling tank 12 is configured so that a constant amount of water 13 constantly flows. An exhaust pipe 9 is provided in the water 13 contained in the cooling tank 12. The hydrogen gas passing through the exhaust pipe 9 is cooled by the water 13 contained in the cooling tank 12. As described above, in the cooling tank 12, the temperature of the gas sucked from the molten copper supply chamber 5 by the vacuum pump 11 is 900 to 1000.
Since it reaches as high as 0 ° C., it is provided to lower the temperature of the gas passing through the exhaust pipe 9. By providing this cooling tank 12, the vacuum pump 11 is protected from high temperature, and the exhaust pipe 9 is protected by the water 13 contained in the cooling tank 12.
When the hydrogen gas passing through the inside is cooled, the volume of the hydrogen gas is reduced, the suction force of the vacuum pump 11 can be increased, and the exhaust efficiency of the gas in the space 10 in the molten copper supply chamber 5 can be improved.

Reference numeral 16 is a supply pipe for quantitatively supplying the molten copper 4 in the molten copper supply chamber 5 to the crucible 150. Reference numeral 17 denotes an inductor, which is an induction furnace for constantly holding the molten copper 4 supplied from the melting furnace and contained in the holding furnace 1 in a molten state.

Next, the operation of this embodiment will be described.

First, the electrolytic copper 120 melted from the melting furnace is constantly supplied and introduced into the molten copper introduction chamber. The electrolytic copper 120 supplied from the melting furnace is supplied from the molten copper introduction chamber to the molten copper pressure chamber 2 in predetermined amounts. An inert gas is regularly supplied to the molten copper pressurizing chamber 2 from a gas supply port 7 of a lid 6 attached to the upper portion of the molten copper pressurizing chamber 2. When the inert gas is supplied into the molten copper pressurizing chamber 2 from the gas supply port 7 at a predetermined pressure, the upper surface of the molten copper 4 introduced in the molten copper pressurizing chamber 2 is pushed down and melted. The molten copper 4 in the copper pressurizing chamber 2 is supplied to the molten copper supply chamber 5 through the lower side of the partition plate 3.

In the molten copper supply chamber 5, from the exhaust pipe 9 of the lid 8 attached to the upper portion of the molten copper supply chamber 5 to the lid 8.
The gas in the space 10 formed by the upper end of the molten copper 4 in the molten copper supply chamber 5 is sucked by the vacuum pump 11 and is kept in a vacuum state (5 to 20 TORR). When the gas in the space 10 is sucked by the vacuum pump 11, the space 10 is depressurized (becomes a negative pressure), and the hydrogen gas contained in the molten copper 4 can be easily moved upward. Therefore, the hydrogen gas contained in the molten copper 4 passes through the molten copper 4 and is discharged into the space 10 from the upper end surface of the molten copper 4 in the molten copper supply chamber 5. The hydrogen gas thus discharged into the space 10 is sucked by the vacuum pump 11 through the exhaust pipe 9 and discharged from the vacuum pump 11 to the outside.

Gas discharged into the space 10 (in particular, hydrogen gas discharged into the space 10 from the upper end surface of the molten copper 4)
Is discharged to the atmosphere through the exhaust pipe 9 housed in the cooling tank 12 in which a fixed amount of water 13 quantitatively supplied from the water supply pipe 14 is housed, is cooled, and is housed in the vacuum pump 11. To be done.

Therefore, according to this embodiment, the space 10 formed by the lid portion 8 of the molten copper supply chamber 5 and the upper end surface of the molten copper 4 in the molten copper supply chamber 5 is decompressed, The hydrogen gas can be degassed.

Further, according to the present embodiment, the vacuum pump 11 is directly connected to the upper lid portion 8 of the molten copper supply chamber 5 and the lid portion 8 of the molten copper supply chamber 5 and the molten copper 4 in the molten copper supply chamber 5 are connected. The space 10 formed by the upper end surface of the
The hydrogen gas in the molten copper 4 can be degassed.

[0032]

Since the present invention is constructed as described above, it has the following effects.

Since the space between the lid of the molten copper supply chamber and the upper end of the molten copper is decompressed to degas the hydrogen gas contained in the molten copper, the hydrogen gas contained in the molten copper is reduced to about 1%. .5 × 10
^The amount of solid solution can be suppressed to ^-4 (wt%) or less, and it is possible to prevent pinholes from forming in the columnar structure of the casting rod and to prevent blister scratches when rough drawing. it can.

Further, a vacuum pump is directly connected to the upper lid portion of the molten copper supply chamber to maintain the gap between the lid portion of the molten copper supply chamber and the upper end portion of the molten copper in a vacuum state so that hydrogen gas in the molten copper is discharged. In order to degas, the hydrogen gas contained in the molten copper is about 1.
The amount of solid solution can be suppressed to 5 × 10 ^-4 (wt%) or less, which prevents the generation of pinholes in the columnar structure of the casting rod and prevents the occurrence of bruise scratches when the wire is drawn rough. can do.

Further, since the cooling tank is interposed between the upper lid part of the molten copper supply chamber and the vacuum pump, the gas exhaust efficiency of the space in the molten copper supply chamber can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional overall configuration diagram showing an example of a holding furnace of a DFP casting apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram of a DFP casting apparatus.

FIG. 3 is a partial cross-sectional overall configuration diagram showing an example of a holding furnace of a conventional DFP casting apparatus.

FIG. 4 is a metallographic view of the casting rod shown in FIG.

5 is a diagram showing a state in which pin holes are formed in the casting rod shown in FIG.

FIG. 6 is a view showing a state in which a rough wire produced by the DFP casting apparatus shown in FIG.

[Explanation of symbols] 1 ……………………………………………………………… Holding furnace 2 ……………………………………………… …………… Molten copper pressure chamber 3 ……………………………………………………………… Partition plate 4 …………………………………… ……………………………… Molten copper 5 ……………………………………………………………… Molten copper supply chamber 6, 8 ………………………… ………………………………………… Lid 9 ……………………………………………………………… Exhaust pipe 10 …………………… …………………………………………… Space 11 ………………………………………………………… Vacuum pump 12 …………………… ………………………………………… Cooling tank 17 ………………………………………………………… Inductor 100 ………………………… ………………… ............ D
FP casting machine 150 ………………………………………………………… Crucible 160 ……………………………………………………… Core rod line

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[Procedure amendment]

[Submission date] April 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Further, the pinhole 250 formed by the hydrogen gas remaining in the columnar structure does not disappear even if the grown copper wire to which the molten copper adheres is rolled in the next rolling step and is drawn by a rough drawing line. Appears as a blemish scratch 300 as shown in 6. When such fence and a wound 300 remains in wire rod
There is a problem that the wire may be broken when repeatedly bent .

Claims (3)

[Claims] 1. A molten copper supply chamber of a molten copper holding chamber comprising a molten copper introduction chamber, a molten copper pressurizing chamber, and a molten copper supply chamber, and a holding furnace for maintaining a molten state by an inductor. In a DFP casting apparatus having a crucible for temporarily casting molten copper supplied from the molten copper and passing a core rod wire upward in the molten copper to manufacture a casting rod, the molten copper is melted with a lid of a molten copper supply chamber. A holding furnace of a DFP casting apparatus in which the space between the copper and the upper end is decompressed to degas hydrogen gas in molten copper. 2. A molten copper supply chamber having a molten copper holding chamber comprising a molten copper introduction chamber, a molten copper pressurizing chamber and a molten copper supply chamber, and a holding furnace for maintaining a molten state by an inductor. In a DFP casting apparatus having a crucible for temporarily storing molten copper supplied from the molten copper and passing a core rod wire upward in the molten copper to manufacture a cast rod, an upper lid portion of the molten copper supply chamber is provided. A vacuum pump is directly connected to the chamber to keep the space between the lid of the molten copper supply chamber and the upper end of the molten copper in a vacuum state to degas the hydrogen gas in the molten copper.
Holding furnace for FP casting equipment. 3. A holding furnace for a DFP casting apparatus according to claim 2, wherein a cooling tank is interposed between an upper lid of the molten copper supply chamber and a vacuum pump.