JPH0741372B2 - Continuous casting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention is particularly useful for continuously melting and casting high-quality pure copper and copper alloy materials used in magnet wires of electronic parts. The present invention relates to a suitable continuous casting furnace.

“Prior art” In recent years, copper wires, which are mainly copper, have rapidly become ultrafine wires due to the increasing demand for electric wires for electronic devices, magnet wires, etc. I'm out.

In such a trend of thinning, the wires for extra fine wires are
Copper roughing wire is used by continuous casting and rolling method (SCR process), DIP forming method, etc., but in either method, there is no degassing step, and gas and volatility etc. are generated to improve the soundness of the roughing material. There are problems such as poor points and the inclusion of metal impurities in the roughing material due to the hot rolling process.

Therefore, the present applicant has proposed a casting furnace for vacuum degassing and melting and casting such copper and copper alloy (Japanese Patent Application No. 58-21183).
See No. 9).

FIG. 3 is a diagram showing a casting furnace proposed by the present applicant. In a casting furnace a shown in this figure, an exhaust pipe c and an air supply pipe d are connected to a vacuum chamber b, a melt casting crucible e is installed inside, and a longitudinal direction is a vertical direction above the melt casting crucible e. A casting mold f, one end of which is opened to the outside of the vacuum chamber b, is movably arranged vertically. In this casting furnace a, after the air is exhausted from the exhaust pipe c to make the inside of the vacuum chamber b vacuum, the copper and copper alloy materials are melted by the melt casting crucible e, and then the air supply pipe d is used. Vacuum chamber b with inert gas
It is configured such that the molten metal in the melt-casting crucible e is introduced into the inside of the casting mold f and is pushed above the casting mold f, and while being solidified, it is extracted upward by the pinch roller g to continuously obtain a cast material.

“Problems to be Solved by the Invention” By the way, in the case of the casting furnace a, the melting casting crucible e
When the molten metal inside is exhausted by casting, copper and copper alloy raw materials must be newly charged and melted. Further, in the casting furnace a, melting of the material, vacuum degassing, and casting are sequentially performed in the melting and casting crucible e. For this reason, there is a problem that casting cannot be performed while the raw material is loaded into the melt-casting crucible e, and while melting and vacuum degassing are performed, resulting in poor production efficiency.

The present invention has been made in view of the above circumstances, and an object thereof is continuous loading of materials, melting, degassing, and casting, which can improve productivity. To provide a casting furnace.

"Means for Solving Problems" In order to achieve the above-mentioned object, the present invention provides a raw material charging chamber for continuously charging a raw material, and a casting gas connected to the raw material charging chamber. A closed chamber, an air supply and exhaust means provided in the casting airtight chamber for controlling the pressure in the casting airtight chamber, and provided in either the raw material chamber or the casting airtight chamber, in the raw material charging chamber A melting means for melting the charged raw material material, a degassing means for degassing the gas in the molten metal melted by the melting means, a casting nozzle having one end opening into the casting hermetic chamber, and the casting It is provided in the vicinity of the nozzle, and is provided with a transfer means for continuously pulling up the cast product formed in the casting nozzle from the molten metal stored in the casting hermetic chamber.

"Operation" In the continuous casting furnace of the present invention, while melting the raw material charged in the raw material charging chamber by the melting means,
The gas in the molten metal is degassed by the degassing means, the pressure in the casting hermetic chamber is controlled by the air supply and exhaust means, and the molten metal in the casting hermetic chamber is drawn out by the casting nozzle and cast. To do.

[Examples] Examples of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a diagram showing a continuous casting furnace according to the first embodiment of the present invention. This continuous casting furnace has a raw material charging chamber 1 for charging raw materials, a casting hermetic chamber 4 communicating with the raw material charging chamber 1 and having air supply and exhaust means 2, 3, and one end thereof. A casting nozzle 5 opened in a casting hermetic chamber 4 and a raw material charging chamber 1
Melting means 6 for melting the raw material supplied to the inside
And degassing means 7 for degassing the gas in the molten metal.

The raw material charging chamber 1 is for charging the pure copper or copper alloy raw material as a raw material continuously or intermittently, and a copper cathode (or a copper alloy raw material) is provided above it.
A conveyor 9 for carrying in 8 and a pinch roller 11 for supplying the pure copper seed wire 10 are arranged, and a supply nozzle 12 penetrating inward from the side and an inert gas (Ar) are arranged at the lower part thereof. Or supply pipe for reducing atmosphere gas (CO + N ₂ )
13 and a supply valve 14 for controlling the supply of the gas
The degassing means 7 is provided. The bottom of the raw material charging chamber 1 is communicated with the casting hermetic chamber 4, and the melting means 6 is provided at the communicating bottoms of the chambers 1 and 4.

This melting means 6 is a means for inducing electromotive force by an electromagnetic induction action of alternating current by a low frequency groove type induction melting method, and heating and melting a metal by the generated jule heat. 15 and a secondary circuit groove 16. In addition,
Reference numeral 17 is a plug for removing the residual hot water in the secondary circuit groove 16. In addition to the melting by the low frequency induction heating,
A method such as high frequency induction heating or electric resistance heating may be adopted.

The height of the raw material charging chamber 1 is set so that the molten metal does not overflow from the raw material charging chamber 1 due to the introduction of the raw material or the pressure fluctuation (pressurization) in the casting hermetic chamber 4. It is set sufficiently higher than the height of the airtight chamber 4, and the cross-sectional area of the casting airtight chamber 4 is set so as to suppress fluctuations in the molten metal level due to pressure changes in the casting airtight chamber 4 to be small. It is set to be sufficiently larger than the cross-sectional area of the charging chamber 1. Further, the chambers 1 and 4 and the secondary circuit groove 16 of the melting means 6 are kept airtight by a shell 18 and a refractory 19, respectively, and at the upper end of the raw material charging chamber 1. A furnace lid 20 is arranged.

The casting hermetic chamber 4 is provided with an air supply means 2 having an air supply valve 21 and an air supply pipe 22 and an exhaust means 3 having an exhaust valve 23 and an exhaust pipe 24 on the upper side surface. The inside of the closed chamber 4 can be pressurized to 0 to 1 kg / cm ² with an inert gas (Ar) or a reducing atmosphere gas (CO + N ₂ ),
It can be adjusted to a predetermined pressure and held. A casting nozzle 5 is provided above the casting hermetic chamber 4. The casting nozzle 5 is used in the casting hermetic chamber 4
It is used to cast a linear copper material or copper alloy material from the molten metal in the upward direction, and is formed into a cylindrical shape. It is designed to cast shaped wire rods. Further, a cylindrical water-cooled jacket 25 is provided on the outer periphery of the casting nozzle 5 so as to penetrate the shell 18 and the refractory material 19 in the upper portion of the casting hermetic chamber 4. The water-cooled jacket 25 is used for cooling the molten metal in the casting nozzle 5 and rapidly solidifying it, and is made of copper, and the cooling water circulates in the cylindrical hollow portion. The water cooling jacket 25 is provided so as to be vertically movable together with the casting nozzle 5 while maintaining the casting hermetic chamber 4 in an airtight state.

Above the casting nozzle 5, a pinch roller 26
Is provided so as to be vertically movable together with the casting nozzle 5 and the water cooling jacket 25. This pinch roller 26
Is for pulling up the casting rod (wire) in the casting nozzle 5. On the other hand, at the lower end of the water cooling jacket 25, a molten metal level sensor 27 for detecting the molten metal level in the casting hermetic chamber 4 is provided so as to project downward. Furthermore, the wire rod 28 pulled up by the pinch roller 26
Is wound into a coil by the coiler 29. A dancer 30 is installed in front of the coiler 29 to absorb a change in wire speed due to vertical movement of the casting nozzle 5 and to stabilize the winding tension of the coiler 29.

Depending on the case, a ceramic melt filter 31 may be provided between the raw material charging chamber 1 and the casting hermetic chamber 4, or a heater may be provided in the refractory 19 of the raw material charging chamber 1. May be provided, or a quartz tube for supplying gas (Ar, CO, N ₂ ) may be inserted from above the raw material charging chamber 1.

Next, a case will be described in which a linear casting material made of copper or a copper alloy is continuously cast using the continuous casting furnace configured as described above.

In this continuous casting furnace, since the low-frequency induction melting method is used as the melting means 6, before the start of melting, the melt is filled in the secondary circuit groove 16 from the outside in advance, or the furnace body is manufactured. At the stage of, the solid ring made of the melting raw material is inserted into the secondary circuit groove 16. Next, by inducing electromagnetic induction electromotive force by energizing the primary-side low-frequency coil 15 with alternating current, and generating jule heat in the raw material in the secondary circuit groove 16 or the molten metal, the temperature rises to a temperature at which the raw material can be melted. Then, the molten metal is filled up to the molten metal surface position L ₀ .

Then, from the upper part of the furnace lid 20 with the center opened at the upper end of the raw material charging chamber 1, the pure copper seed wire 10 is passed through the pinch roller 11 or the copper cathode (or copper alloy material) 8 is conveyed by the conveyor 9 It is charged into the raw material charging chamber 1 via. At this time, inside the raw material charging chamber 1 and the casting hermetic chamber 4, an inert gas or a reducing atmosphere gas is supplied to the inert gas atmosphere or the reducing gas using the degassing means 7, the gas feeding means 2 and the exhaust means 3. Fill with atmosphere and keep at atmospheric pressure.

Then, the charged raw material materials 8 and 10 are melted as they reach the molten surface L ₀ and become molten. Accordingly, by continuously charging the raw material materials 8 and 10, the raw material material charging chamber 1 and the casting hermetic chamber 4 start to be filled with the molten metal from the bottom. In this case, since both chambers 1 and 4 are maintained at the atmospheric pressure, the molten metal level gradually rises while maintaining the same level, and reaches the molten metal level position L ₁ . At this point, the supply nozzle 12 is located below the molten metal surface L ₁ , but since the inert gas or the reducing gas is being fed under pressure, the gas becomes a bubble and is blown into the molten metal and is directed upward. Once it rises. Here, since the space between the raw material charging chamber 1 and the casting airtight chamber 4 is partitioned by the molten metal weir 32 which is open only at the bottom, the gas blown into the raw material charging chamber 1 is It does not flow to the casting hermetic chamber 4 side.

In this state, the casting nozzle 5 is immersed in the lower portion of the molten metal surface L ₁ into the molten metal, but the molten metal surface sensor 27 attached to the lower end of the water cooling jacket 25
The position of L ₁ is detected, and the vertical movement device (not shown) moves the entire water-cooled jacket 25 up and down so that the lower end of the casting nozzle 5 has a constant depth with respect to the molten metal surface L ₁ . In this way, the position control of the casting nozzle 5 with respect to the molten metal surface L ₁ is continuously performed by the molten metal sensor 27.

Then, a seed wire having a diameter corresponding to the inner diameter of the casting nozzle 5 is inserted from the upper opening of the water-cooled jacket 25. Then, an inert gas or a reducing atmosphere gas is introduced into the casting hermetic chamber 4 by using the air feeding means 2 to pressurize the casting hermetic chamber 4 from the atmospheric pressure to keep it at a constant pressure (for example, With gauge pressure
1kg / cm ² or less).

As a result, the molten metal surface position in the casting hermetic chamber 4 is gradually lowered from L ₁ to the molten metal surface position L ₂ , and the raw material charging chamber 1
The molten metal surface position inside gradually rises from L ₁ to the molten metal position L ₃ . In this case, the level difference between the molten metal surfaces L ₃ and L ₁ in both chambers 1 and 4 is determined by the pressure difference between the atmospheric pressure in the raw material charging chamber 1 and the pressurized state in the casting hermetic chamber 4, For example, the inside of the casting hermetic chamber 4 is 0.
5kgf / cm ² (gauge pressure), the inside pressure of the raw material charging chamber 1 is atmospheric pressure, and the specific gravity of the molten metal is 8.3, the level difference is about 600mm.
Becomes On the other hand, the casting nozzle 5 descends to a certain depth with respect to the molten metal surface position L ₂ by the molten metal surface sensor 27 detecting the descent of the molten metal surface from L ₁ to L _2, and Maintain

Further, when the casting hermetic chamber 4 is pressurized with a constant pressure as described above, the molten metal in the chamber is pushed up into the casting nozzle 5 and comes into contact with the seed line inserted from the upper portion of the water cooling jacket 25. In this state, when the seed wire is pulled upward continuously or intermittently, the molten metal is cast along with the rise of the seed wire.
Rise inside. The molten metal is cooled by a water-cooled jacket 25 and is connected to a round wire (deformed wire) 28 made of copper or a copper alloy having an outer diameter corresponding to the inner diameter of the casting nozzle 5 from the upper end of the water-cooled jacket 25. Be withdrawn. Next, the drawn wire 28 is wound into a coil shape in a stable state and smoothly by the coiler 29 via the dancer 30 to obtain a long wire. Then, the obtained wire rod is subjected to wire drawing or rolling in a subsequent process to have a desired shape and size.

Further, the amount of molten metal in the casting hermetic chamber 4 decreases as the wire rod 28 is drawn out. However, by gradually feeding the raw material into the raw material charging chamber 1 to compensate for the reduced amount of molten metal, Maintain levels L ₂ and L ₃ constant.

In this way, the raw material materials 8 and 10 charged into the raw material material charging chamber 1 are melted by the melting means 6 and the inert gas blown into the molten metal from the lower part of the raw material material charging chamber 1 is melted. Alternatively, it is degassed by levitating the impure gas contained in the molten metal and causing gas porosity by the reducing atmosphere gas, and is further stored in the casting hermetic chamber 4 and pressurized in the casting hermetic chamber 4. The casting nozzle 5 allows the casting nozzle 5 to pull upward and cast.

Therefore, according to the present embodiment, the raw material can be melted under atmospheric pressure, and as a result, the raw material can be continuously and easily loaded and melted regardless of the shape of the raw material. Therefore, degassing can be performed continuously in the raw material charging chamber 1 while melting the raw material. Further, since the depth of the molten metal in the raw material charging chamber 1 can be set sufficiently, the contact or the reaction between the blown-in inert gas or the reducing atmosphere gas and the molten metal proceeds, and the degassing can be sufficiently performed. it can.

Further, in the casting hermetic chamber 4, the wire having a desired cross-sectional shape can be continuously cast from the degassed molten metal by the casting nozzle 5. Further, the static pressure of the molten metal in the casting hermetic chamber 4 can be maintained constant, and the molten metal is pushed up in the direction opposite to the gravity direction by pressurizing with the inert gas or the reducing atmosphere gas, so that When solidified, it becomes a pressurized state, the soundness of the cast material is greatly improved, and a homogeneous cast material can be obtained.

Although the casting nozzle 5 is provided in four sets in the above embodiment, the present invention is not limited to this.
1 set or a plurality of sets may be provided and may be adjusted according to the production amount.

Further, FIG. 2 is a view showing a second embodiment of the present invention. In this second embodiment, a raw material charging chamber 40 is provided in the center of a cylindrical casting hermetic chamber 41 from above to inside. A plurality of casting nozzles 5 and a casting unit such as a water-cooled jacket 25 are arranged at equal intervals around the raw material charging chamber 40, and the raw material charging chamber 40 and the casting hermetic chamber are connected. 41
A heating means 42 such as electric resistance heating or high-frequency induction heating is arranged around, while the raw material charging chamber 40
A quartz tube 43 for injecting an inert gas or a reducing atmosphere gas is inserted therein. The rest of the configuration is similar to that of the first embodiment, so the same reference numerals are given and the description thereof is omitted.

Even in the continuous casting furnace of the second embodiment configured as described above, the same effect as that of the first embodiment can be obtained.

"Effects of the Invention" As described above, according to the present invention, a raw material charging chamber for charging a raw material and a communication with the raw material charging chamber,
Also, a casting hermetic chamber having air supply and exhaust means, a casting nozzle having one end opened to the casting hermetic chamber, a melting means for melting the raw material supplied into the raw material charging chamber, and a molten metal. Since it is provided with a degassing means for degassing the gas inside, the raw material charged into the raw material charging chamber is melted by the melting means and melted by the degassing means. By degassing the gas in the hot water, controlling the pressure in the casting hermetic chamber by the air supply and exhaust means, and drawing the molten metal in the casting hermetic chamber by the casting nozzle to cast the raw material, The processes of charging, melting, degassing, and casting can be carried out compactly and continuously, so that the equipment cost can be reduced and the process and casting time can be shortened. In addition, it is possible to continuously produce a stable and high-quality cast material with high soundness, and thus it is possible to reduce the production cost of the cast material.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention, and FIG. 3 is a schematic configuration diagram showing a conventional casting furnace. 1 ... Raw material charging chamber 2 ... Air feeding means 3 ... Exhausting means 4 ... Casting airtight chamber 5 ... Casting nozzle 6 ... Melting means 7 ... Degassing means 8 ... Copper cathode (copper alloy material) ) 10 …… pure copper seed wire 40 …… raw material charging chamber 41 …… casting hermetic chamber 42 …… heating means 43 …… quartz tube.

Claims (1)

[Claims] 1. A raw material charging chamber (1,40) for continuously charging a raw material (8,10), and a casting hermetic chamber (1) connected to the raw material charging chamber (1,40). Four,
41) and the casting hermetic chamber (4, 41), and the casting hermetic chamber (4, 4)
1) Air supply and exhaust means (2, 3) for controlling the pressure inside, and the raw material chamber (1, 40) or the casting hermetic chamber (4, 41)
And a melting means (6, 6) for melting the raw material material (8, 10) charged in the raw material material charging chamber (1, 40).
42), degassing means (7,43) for degassing the gas in the molten metal melted by the melting means (6,42), and one end of which opens into the casting hermetic chamber (4,41) The casting nozzles (5, 5 ...) And the casting nozzles (5, 5 ...) that are provided in the vicinity of the casting nozzles (5, 5 ...) From the molten metal stored in the casting hermetic chamber (4, 41).
A continuous casting furnace provided with a transfer means (26) for continuously pulling up a cast product formed in the inside of the casting furnace.