JP3570084B2 - Bottom hole tapping type flotation melting equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom hole tapping type flotation and melting apparatus capable of easily removing metal remaining in a crucible after tapping molten metal from the bottom.
[0002]
[Prior art]
A levitation melting device places a material to be melted in an alternating magnetic field generated so as to have a predetermined distribution, and utilizes eddy current flowing through the material to be melted by electromagnetic induction to induce levitation force due to induction heating and electromagnetic force. An apparatus in which both are given at the same time and the material is melted in a state where it does not come into contact with other objects such as a floating crucible to obtain a product of a predetermined material and size. It has a high melting point and a high melting point because it has features such as extremely low contamination with foreign matter because it does not come into contact with other objects during melting, the ability to melt even materials with a high melting point, and a small heat conduction loss. It is used for a material requiring purity, for example, a melting material such as titanium and silicon.
[0003]
FIG. 7 shows a configuration diagram of a conventional example. In FIG. 7, reference numeral 1 denotes a crucible made of a good conductive metal having a bottomed cylindrical shape and having vertically elongated slits radially provided in the cylindrical portion at substantially equal intervals, 1 a denotes an outlet of the molten metal 2, and 3 a denotes an outlet of the molten metal 2. The induction coil mainly applies melting and heating power to the material to be melted by using eddy current flowing by electromagnetic induction, and 3b gives buoyancy to the molten metal to the material to be melted by utilizing eddy current flowing by electromagnetic induction. The lower induction coil, 4a is an AC power supply for supplying current to the upper induction coil 3a, 4b is an AC power supply for supplying current to the lower induction coil 3b, and 6 is a plug for closing the outlet 1a.
[0004]
With the above configuration, the crucible 1 is configured by arranging two or more electrically insulated segments inside the induction coils 3a and 3b. The material to be melted is put in the crucible 1, and the magnetic flux generated by the induction coils 3a and 3b enters the crucible from the gap between the slits between the segments and interlinks with the material to be melted. The segments constituting the crucible 1 are water-cooled so as not to melt.
[0005]
The current in the induction coils 3a and 3b induces eddy currents in the electrically isolated segments and also induces eddy currents in the material to be melted. The directions of the eddy currents flowing through the crucible 1 and the material to be melted are opposite to each other at the opposing surface portions, so that magnetic repulsion is generated. Since the crucible 1 is fixed, the levitation force is applied to the material to be melted. When the levitation force is larger than the weight of the material to be melted, the material to be melted floats away from the crucible 1. The material to be melted generates heat due to resistance loss and continues to be heated. Therefore, the material to be melted is dissolved in a floating state. Here, in order to prevent the material to be melted from coming into contact with the crucible 1, it is desirable that the material to be melted be stably located at the central portion of the crucible 1. In order to stably float in the crucible 1, it is necessary to increase the electromagnetic repulsion from the crucible 1 against the weight of the material to be melted toward the bottom of the crucible. In order to increase the electromagnetic repulsion at the bottom of the crucible, a current is supplied to the lower induction coil 3b wound around the bottom of the crucible from an AC power supply 4b having a lower frequency so that a larger levitation force is obtained as compared with the upper induction coil 3a. Then, a high-frequency current for melting the material to be melted is supplied to the upper induction coil 3a from another AC power supply 4a.
[0006]
There are various methods for taking out the molten metal 2 melted by the flotation melting apparatus, but there is a method in which an outlet 1a is provided at the bottom of the crucible 1 and the molten metal is continuously or intermittently taken out from the outlet 1a. No. 5,009,045. According to this publication, a method of taking out the molten metal is such that a molten metal outlet 1a is provided at the bottom of the crucible 1 and the material in the crucible is melted while the current of the induction coil 3 is controlled to be substantially constant. The small pieces 5 are continuously or intermittently supplied from the upper portion of the crucible 1, and the molten metal 2 corresponding to the supply amount is continuously or intermittently discharged from the outlet 1a, taken out, and injected into the next step such as pouring into a mold. How to
[0007]
In the case of a flotation and melting device that discharges molten metal from the lower part of the crucible, a small amount of molten metal is melted in the initial stage of melting, and when the small amount of molten metal does not reach the amount that the molten metal can float due to the floating force. There is a risk of falling from the outlet of the refractory, and in order to prevent this, and to prevent the molten metal from losing its buoyant force and dropping from the outlet when melted and loses buoyancy during melting. A stopper 6 is used. However, when the molten metal comes into contact with the plug of the refractory, the refractory melts into the molten metal and lowers the purity of the molten metal. 227598.
[0008]
Further, the tapping of the flotation apparatus using the tap 6 is disclosed in JP-A-7-245182. According to this gazette, it is possible to freely control the timing and the amount of hot water by closing the outlet 1a with the plug 6 and opening the plug 6 at the time of tapping. Further, according to this, the tap 6 and the molten metal 2 exert repulsive force on each other at the time of tapping, so that tapping can be performed without contact with the tap 6. After completely dissolving the molten material, the tap 6 is opened to start tapping (see FIG. 8), and after the molten metal 2 is stopped halfway or the tapping is completed, the stopper 6 is closed and the melting material is added and repeated. This enables continuous operation.
[0009]
[Problems to be solved by the invention]
By the way, in the conventional configuration, since the induction coil is not wound in parallel with the crucible, the distribution of the magnetic field in the crucible is not axially symmetric, the magnetic field intensity at the center of the crucible outlet is close to zero, and is included in the melting material. Due to the presence of impurities such as oxides present on the surface of the molten metal and remaining in the crucible at the time of complete tapping, the molten metal may remain as a dripping 10 near the outlet 1a of the crucible when the tapping is stopped (FIG. 9). (A)). If this dripping occurs once during the tapping, it solidifies and becomes a seed, from which dripping 10 grows as dripping growth 10a (see FIG. 9B). In both cases of FIGS. 9 (a) and 9 (b), the plug cannot be closed again, making continuous operation difficult. The molten metal remaining near the crucible outlet is designed to be sufficiently cooled because the eddy current is concentrated and heated most when energized near the crucible outlet. The metal remaining near the crucible outlet is in a normal state because the eddy current flowing in the metal remaining near the crucible outlet is small compared to that during normal melting because the amount of remaining metal is small. It is difficult to dissolve by applying current.
[0010]
The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to make it possible to easily remove metal remaining in the vicinity of a crucible outlet, thereby enabling continuous operation by using a bottom-hole tapping type flotation melting. It is to provide a device.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, a good conductive material having a bottomed cylindrical shape, an outlet for discharging the melt formed at the bottom, and vertically long slits radially provided at substantially equal intervals in the cylindrical portion. In a bottom hole tapping type flotation / melting apparatus equipped with a metal crucible, an induction coil provided on the outer diameter side of the crucible, and an AC power supply for supplying a high-frequency current to the induction coil, the same material as the molten metal is used. A bottom hole tapping type flotation melting apparatus in which a pipe-shaped adapter having an outer diameter substantially equal to the inner diameter of the outlet is attached to the outlet.
[0012]
With the above structure, the adapter is cooled from the outer diameter side in contact with the outlet, so that the adapter does not melt, and after the tapping, the solidified metal remaining in the vicinity of the tap hole is dripped down through the pipe hole of the adapter. If the outer diameter is within the outer diameter of the adapter, the solidified metal and the adapter can be taken out from the outlet.
According to a second aspect of the present invention, in the bottom hole tapping type flotation melting apparatus according to the first aspect, the adapter is a bottom hole tapping type flotation melting apparatus having one or more slits in a longitudinal direction.
[0013]
With the above configuration, the eddy current does not go around the adapter during the melting, so that the heating of the adapter is suppressed and the melting of the adapter during the melting can be prevented.
According to a third aspect of the present invention, in the bottom hole tapping type flotation melting apparatus according to claim 1 or 2, the adapter is a bottom hole tapping type flotation melting apparatus longer than the length of the outlet.
[0014]
With the above configuration, it is possible to prevent the dripping from spreading downward.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
1A and 1B show a configuration of a main part of an embodiment of the present invention, wherein FIG. 1A is an external view of an adapter, and FIG. In FIG. 1, members denoted by the same reference numerals as those of the conventional example have approximately the same functions, and therefore, description thereof will be omitted. In FIG. 1, the adapter 7 has a cylindrical shape, the outer diameter is substantially the same as the inner diameter of the outlet 1a, and the height is also substantially the same as the height of the outlet 1a. When the adapter 7 is attached to the outlet 1a of the crucible 1 and melting and tapping are performed, even if oxides and the like of the molten metal remain near the outlet 1a, the dripping spreads beyond the outer diameter of the adapter 7. Since it does not exist, it does not adhere to the wall surface of the tapping pipe portion 1c, and the dripping can be taken out after solidification.
[0017]
The material of the adapter 7 is the same as the material of the molten metal.
FIG. 2 shows a configuration diagram of a main part of another embodiment of the present invention. 2 differs from FIG. 1 in that one or more slits 9 are provided in the longitudinal direction of the adapter. In FIG. 2, one slit 9 is provided so as to completely cut the circumference of the cylinder. However, when a plurality of slits 9 are provided, one of the slits 9 completely cuts the circumference and the other slits 9 are high. The distance may be up to the middle.
[0018]
3A and 3B show a configuration of a main part of another embodiment of the present invention, wherein FIG. 3A is an external view of an adapter, and FIG. The adapter 70a of FIG. 3 differs from that of FIG. 2 in that the height of the adapter is increased so that the adapter 70a protrudes below the outlet 1a of the crucible 1 and projects into the tapping pipe portion 1c. .
[0019]
4A and 4B show a main part of still another embodiment of the present invention, wherein FIG. 4A is an external view of an adapter, and FIG. 4B is a diagram in which the adapter is mounted below the outlet. In FIG. 4, the adapter 8a has a cylindrical shape whose tip end is tapered so as to follow the shape of the tapping pipe portion 1c. The material of the adapter 8a is either the same material as the molten metal or ceramics. In the case of the same material as the molten metal, an umbrella-shaped adapter 8b may be used as shown in FIG. Further, as shown in FIG. 6, a plurality of slits 9 may be provided to cut off the eddy current in the adapter 8c.
[0020]
【The invention's effect】
According to the present invention, the adapter remaining in the vicinity of the outlet after the melting and tapping is solidified and the adapter can be easily taken out from the outlet, so that the operation stoppage time due to dripping during continuous operation is reduced, and the operation rate of the apparatus is reduced. This has the effect of improving productivity as well as improving the productivity.
[0021]
Also, if the oxides generated before or during melting are left at the time of tapping and solidified and removed in the vicinity of the tapping hole, the discharged molten metal becomes clean and has an effect of increasing purity. Further, since the amount of hot water per unit time can be changed by changing the inner diameter of the adapter, if adapters having different inner diameters are prepared, there is an effect that hot water can be discharged at a desired outflow amount.
[Brief description of the drawings]
FIG. 1 shows a configuration of a main part of an embodiment of the present invention, in which (a) is an external view of an adapter, and (b) is a diagram in which the adapter is attached to an outlet. FIG. 2 is another embodiment of the present invention. FIG. 3 shows a configuration of a main part of another embodiment of the present invention. FIG. 3 (a) is an external view of an adapter, and FIG. 3 (b) is a view in which the adapter is attached to an outlet. 4 shows the structure of the main part of still another embodiment of the present invention, wherein (a) is an external view of the adapter, and (b) is a view in which the adapter is mounted below the outlet. FIG. 6 is an external view of an adapter provided with a plurality of slits. FIG. 7 is a configuration diagram of a conventional example. FIG. 8 is a view showing a state of tapping from an outlet. FIG. 9 is a view near an outlet. Diagram showing a state in which dripping has occurred.
DESCRIPTION OF SYMBOLS 1 Crucible 1a Outflow port 1c Tapping pipe part 7, 70, 70a Adapter 8a, 8b, 8c Adapter 9 Slit

Claims (3)

A crucible made of a good conductive metal having an outlet for discharging molten metal formed at the bottom and having a vertically elongated slit radially provided at substantially equal intervals in the cylindrical portion, and the outer diameter of the crucible In the bottom hole tapping type flotation and melting apparatus equipped with an induction coil provided on the side and an AC power supply for supplying a high-frequency current to the induction coil, it is made of the same material as the molten metal, and has an outer diameter substantially equal to the inner diameter of the outlet. A bottom hole tapping type flotation / melting apparatus characterized in that a pipe-shaped adapter is attached to an outlet. The bottom hole tapping type floating melting apparatus according to claim 1, wherein the adapter has a shape having one or more slits in a vertical direction. The bottom hole tapping type flotation melting apparatus according to claim 1 or 2, wherein the adapter is longer than the length of the outlet.

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