JP2000331777A - Bottom tap type floating dissolving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the tapping amount per unit time in a wide range by providing a flow regulating nozzle for regulating the flow rate to a desired flow rate and attachable to and detachable from the outlet port of a copper crucible. SOLUTION: A molten metal 1a is tapped down through a nozzle 7 installed to an outlet port 1b, while the floating force is weakened by the power control of upper and lower induction coils 3, 4. The molten metal tapped per unit time is controlled to a desired quantity by the inner surface of the nozzle 7 and the drawing force of an induction coil 8 wound on the circumferential side of a copper crucible 1 at a part where the nozzle 7 is installed. The molten metal is cooled by a gas blown out through an atomizing nozzle 9 under the nozzle 7 to form powder 10. The inside diameter of the nozzle is selected so that the desired tapping quantity is a value smaller than the maximum tapping quantity of the nozzle 7 at start, and the tapping quantity is controlled to a constant tapping by the drawing force of the induction coil 8 in constant tapping, whereby the control range can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom tapping type floating / melting apparatus for melting a material to be melted in a copper crucible in a floating state and discharging the molten metal from an outlet of the copper crucible and casting it into a mold or atomizing.

[0002]

2. Description of the Related Art Conventionally, a method of tapping a levitation and melting apparatus of this type is based on, for example, reducing the current of a lower induction coil among upper and lower induction coils supplied with currents from separate power sources in the upper and lower directions to reduce the molten metal to a copper crucible. Japanese Patent Laid-Open Publication No. Hei 7-245182 discloses a flotation / melting apparatus in which hot water is discharged from an outlet at the bottom, and a flotation / melting apparatus provided with a control device for continuously controlling the operation from input of a material to be melted to hot water. Japanese Patent Application Laid-Open No. 10-38467 concerning the apparatus and its tapping method further discloses that a crucible made of a copper segment and having an opening at the bottom is mounted in a vacuum or an inert gas atmosphere to dissolve the titanium and make the titanium come into contact with the crucible. The skull is formed so that the molten titanium does not come into contact with anyone other than the skull, and after the melting is completed, the current of the induction coil wound around the outer periphery of the crucible is increased. Flip by flowing down the titanium melt from the bottom opening of the crucible, atomizing grinding the melt into particulate titanium blown substantially perpendicularly inert gas to the tapping stream is described in Japanese Patent Kokoku 7-91571.

[0003]

By the way, in a conventional flotation melting apparatus in which the amount of hot water is controlled by power control using upper and lower induction coils, the power of the lower induction coil is increased to increase the pinch force applied to the molten metal flow. In this case, if the diameter of the molten metal flow becomes smaller than a certain value, there is a limit that the pinch force does not allow the molten metal to be squeezed stably. According to the results of experiments with a practical levitation melting apparatus, the amount of molten metal was determined by the depth of the molten metal and the diameter of the outlet, and almost no adjustment was possible with the vertical induction coil.

[0004] Further, a rising section from the start of tapping until the tapping amount per unit time reaches a constant tapping rate and a falling section from before the end of tapping to the end of tapping take place until the tapping amount becomes constant in the rising section. It takes a long time, the control is impossible during this time, and the falling section is governed by the decrease in the head of the molten metal, and there is a section in which the constant amount of molten metal is not discharged. In these sections, for example, in the case of performing atomization, it is necessary to control the gas flow rate for atomization in accordance with the amount of hot water in order to keep the powder size constant.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to control the amount of molten metal per unit time in a bottom-floating-type flotation melting apparatus by reducing the molten metal by an induction coil. Provided is a bottom tapping-type flotation / melting apparatus capable of controlling over a wider range than possible, and capable of setting a desired tapping amount per unit time from the start to the end of tapping. It is in.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 performs levitation melting in a copper crucible having a plurality of radial slits in a radial direction and an outlet for discharging molten metal at a bottom portion. In the flotation melting apparatus, a flow rate adjusting nozzle that adjusts to a desired flow rate is provided at the outlet of the copper crucible.

According to a second aspect of the present invention, in the bottom tapping type flotation and melting apparatus according to the first aspect, the flow rate adjusting nozzle is formed by dividing the entire control range of the flow rate into a plurality of parts. It is characterized by comprising a plurality of nozzles having an inner diameter corresponding to the maximum flow rate in the control range.

According to a third aspect of the present invention, there is provided the bottom tapping type flotation melting apparatus according to the first or second aspect, wherein a diameter of the molten metal in the nozzle is provided on an outer peripheral side of a portion where the nozzle of the copper crucible is mounted. An induction coil for providing a drawing force for reducing the pressure is provided.

According to a fourth aspect of the present invention, in the bottom tapping type flotation melting apparatus according to any one of the first to third aspects, the flow rate adjusting nozzle is water-cooled.

According to a fifth aspect of the present invention, in the bottom tapping type flotation melting apparatus according to the third or fourth aspect, the induction coil wound on the outer peripheral side of the portion where the nozzle of the copper crucible is mounted is A current is supplied from an AC power source of a variable frequency capable of selecting a frequency suitable for applying a drawing force to the molten metal according to the diameter of the molten metal in the nozzle. When the amount of hot water per unit time is controlled by the configuration of the first to fifth aspects, for example, when the amount of hot water is controlled to 50% with respect to 100% of the amount of hot water per unit time determined by the diameter of the outlet. If the control range is set to 40 to 60% and the diameter of the nozzle attached to the outlet is set to a value corresponding to the 60% tapping amount, the time from the start of tapping to the 50% tapping amount is shortened. By controlling the tapping amount by the induction coil, the tapping amount can be controlled to be maintained at 50% until just before the end of tapping. In this way, by using the combination of the inner diameter of the nozzle and the controllable range by the induction coil throttle, the entire control range of the tapping amount is divided into a plurality of ranges, and the nozzles having a diameter corresponding to each divided range are used. By doing so, it becomes possible to control the amount of hot water per unit time to a desired amount in the entire control range.

Further, when the tapping is stopped, the power supply to the induction coil is stopped to enhance the water cooling of the nozzle and solidify the molten metal in the nozzle, thereby stopping the tapping. When restarting the hot water supply, the cooling of the nozzle is weakened, and the induction coil is energized to melt the metal in the nozzle, thereby making it possible to restart the hot water supply.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a configuration diagram of a main part of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a water-cooled type having a bottomed cylindrical shape, an outlet 1b formed at the bottom for discharging molten metal, and a vertically elongated slit 2 provided at substantially equal intervals in the cylindrical portion. The copper crucible 1a is a molten metal in which a material to be melted is melted in the copper crucible 1, and 3 is a molten metal 1 using an eddy current flowing by electromagnetic induction in the material to be melted.
a is an upper induction coil that mainly supplies induction heating energy to a, 4 is a lower induction coil that mainly supplies a levitation force to the molten metal 1a by an electromagnetic force, 5 and 6 are AC power supplies that supply current to the induction coils 3 and 4, and 7 is Nozzle attached to outlet 1b, 8 is copper crucible 1
An induction coil wound around the outer periphery of the outlet 1b for narrowing the amount of molten metal, and a gas atomizing nozzle 9 for blowing an inert gas into the molten metal discharged from the outlet 1b at a substantially right angle to turn the molten metal into powder 10. Show.

In FIG. 1, when a material to be melted is charged into a water-cooled copper crucible 1 and currents are supplied to the induction coils 3 and 4 from AC power supplies 5 and 6, the currents are supplied to the induction coils 3 and 4. The magnetic flux generated by flowing into the copper crucible 1 passes through the slit 2 and interlinks with the material to be melted to induce an eddy current, and also induces an eddy current in the copper crucible 1. The material to be melted is heated by the eddy current induced in the material to be melted, and an electromagnetic force is generated between the material and the eddy current induced in the copper crucible 1. Since the two eddy currents are opposite to each other on the opposing surfaces, the electromagnetic force becomes a repulsive force. Since the copper crucible 1 is fixed, a levitation force is given to the material to be melted, and the material to be melted melts and floats. It becomes the melt 1a. The molten metal 1a melted in the copper crucible 1 does not come into contact with other objects at the time of melting, so that the amount of foreign matter is extremely small, even a material having a high melting point can be melted, the heat conduction loss is small, and the like. Therefore, it is used for dissolving a material requiring a high melting point and high purity, for example, titanium, a target material and the like.

The molten metal 1a, which has been melted as described above, has its buoyancy reduced by the power control of the vertical induction coils 3 and 4, and flows downward through the nozzle 7 attached to the outlet 1b.
The amount of molten metal discharged per unit time is controlled to a desired amount by the inner diameter of the nozzle 7 and the drawing force of the induction coil 8 wound around the outer periphery of the copper crucible 1 where the nozzle 7 is mounted. Then, the powder 1 cooled by the gas blown out from the atomizing nozzle 9 below the nozzle 7
It becomes 0. The rising time until reaching a fixed amount of hot water is initially rapidly rising. From a certain amount, the amount of hot water gradually increases until the amount of hot water corresponding to the inner diameter of the nozzle 7 is reached. The nozzle inside diameter is selected so as to have a small value, and the nozzle is mounted on the outlet 1b so as to reach a desired amount of hot water quickly to shorten the rise time. In addition, at the time of constant-rate tapping following the tapping start, the tapping force of the induction coil 8 is used to control the constant tapping.
Further, in the last stage of tapping, it is possible to stop the tapping by solidifying the tapping flow in the nozzle 7 by stopping the current supply to the induction coil 8 and stopping the heating of the tapping flow to enhance the cooling of the nozzle 7. In this hot water stopping method, the nozzle 7
Until the molten metal in the tank can be controlled from the constant-rate tapping, it is not a problem because it is in a small quantity.

In this example, the nozzle 7 is directly attached to the outlet 1b. However, the diameter of the outlet at the bottom of the copper crucible 1 is reduced, and a large diameter tapping pipe is provided below the outlet. A nozzle may be attached to the tapping pipe part without providing a nozzle at the outlet.

[0016]

According to the present invention, by changing the inner diameter of the nozzle, it is possible to widen the control range of the fixed amount of hot water per unit time, and to shorten the time of rising and falling of hot water. When the amount of hot water per unit time is required, a single copper crucible can be used, and there is no need to replace the copper crucible or change the diameter of the outflow port, which has the effect of eliminating extra equipment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper crucible 1a Melt 1b Outflow port 2 Slit 3 Upper induction coil 4 Lower induction coil 5, 6 AC power supply 7 Nozzle 8 Induction coil 9 Atomizing nozzle 10 Powder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F27D 11/06 F27D 11/06

Claims (5)

[Claims] 1. A flotation and melting apparatus for performing flotation and melting in a copper crucible having a plurality of radial slits in a radial direction and an outlet for discharging a molten metal at a bottom portion, wherein a desired flow rate is detachable from the outlet of the copper crucible. Bottom tapping type flotation melting apparatus characterized by providing a flow rate adjusting nozzle for adjusting the flow rate. 2. An apparatus according to claim 1, wherein said flow rate adjusting nozzle is divided into a plurality of control ranges of the flow rate and divided into a plurality of control ranges. A bottom-floating-type flotation melting apparatus comprising a plurality of nozzles having 3. An induction coil for applying a drawing force to narrow the diameter of a molten metal in a nozzle in the bottom tapping type flotation and melting apparatus according to claim 1 or 2 on the outer peripheral side of a portion of the copper crucible to which the nozzle is mounted. Bottom tapping type flotation melting apparatus characterized by providing: 4. The bottom tapping type flotation melting apparatus according to claim 1, wherein a nozzle for adjusting the flow rate is a water-cooled type. 5. An inductive coil wound around the outer periphery of a portion of a copper crucible to which a nozzle is attached according to claim 3 or 4, wherein the induction coil wound on the outer peripheral side of the portion where the nozzle of the copper crucible is mounted is adjusted to the diameter of the molten metal in the nozzle. And a current source is supplied from a variable frequency AC power source capable of selecting a frequency suitable for applying a drawing force to the molten metal.