JP3109072B2 - Continuous metal production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously casting a highly reactive high melting point metal as close to a product as possible.

[0002]

[Prior art]

Means for melting high-melting and highly reactive metals such as titanium and zirconia are conventionally known as induction heating using a ceramic crucible, arc melting in a crucible having a low-temperature wall, induction-slag crucible, and the like. The method has been adopted.

[0003] For example, for details of the induction-slag crucible method, see the document DJ.
Chronister, SWScott, DRStickle, D.Eylon and FHF
roes, JOURNAL OF METALS, September 1986, P51.

That is, as shown in FIG. 4, cooling water can pass through the bottom of a four-part copper segment 2 which has a cylindrical shape as a whole and has a water passage hole 1 inside. A copper bottom plate 4 having a large water passage hole 3 is welded by silver brazing. The gap between the divided portions of the copper crucible divided into four is filled with heat-resistant cement, and the entire apparatus in which a circular energizing coil 5 is arranged around the crucible is installed in a vacuum vessel. .

[0005] However, when dissolving titanium or the like, first, the raw material is put in a crucible, and then granular calcium fluoride is charged. The molten calcium fluoride penetrates between the molten titanium and the crucible and plays a role as an electrical insulator and a role in preventing the crucible from being consumed.

After that, the inside of the container is evacuated and filled with argon gas, and a high-frequency current is supplied to the energizing coil 5. Then, first, the raw material such as titanium is heated and dissolved, and subsequently calcium fluoride is dissolved. Then, as the raw material dissolves, the molten calcium fluoride is extruded near the inner wall of the crucible and moves upward, covering the inner surface of the crucible. On the other hand, the outside of the molten titanium is immediately cooled by the water-cooled crucible, forming a titanium neck similar to that of arc melting. The neck is continuously withdrawn from under the crucible to produce titanium.

[0007]

[Problems to be solved by the invention]

However, the above-described manufacturing method has two main problems. The first problem is that the purity of the refractory metal is reduced. In other words, high melting point and highly reactive metals such as molten titanium are likely to react with the crucible wall through a thin slag film of molten calcium fluoride, resulting in a problem that the purity of the high melting point metal is reduced. I do.

Second, it is difficult to continuously produce a metal having a shape close to a product. That is, in the above-described manufacturing method, the slag is in a solid state near the crucible in contact with the crucible. For this reason, when casting is performed using a crucible having different shapes of the inlet and the outlet, a problem arises that the product cannot be taken out of the crucible, particularly when the area of the outlet is smaller than the area of the inlet.

The present invention has been made in view of such a problem, and is an improvement over the conventional induction-slag crucible method.
It is an object of the present invention to provide an apparatus for increasing the purity of a high melting point / highly reactive metal and continuously producing a high melting point / highly reactive metal having a shape close to a product.

[0010]

[Means for Solving the Problems]

A technique for charging a high-melting metal with high reactivity into a low-temperature crucible and melting the metal while keeping the inner wall of the crucible and the metal in a non-contact state has been partially established, and is known as the Czochralski method. (References TFCizek, J. Electrochem. So
c. Solid State Science and Technology, 132 (1985), 9
63).

When this method is applied to the conventional induction-slag crucible method and the slag is removed from the inside of the crucible, the shape of the metal almost matches the shape of the crucible. Can be changed arbitrarily. In addition, since the molten metal is not in contact with the crucible, the purity of the metal can be increased.

That is, in the first aspect of the present invention, the metal raw material supplied into the cooling crucible is once induced by a high-frequency current applied to a coil arranged on the outer periphery of a slit provided in a part of the crucible in the height direction. It is heated and melted and floated in a non-contact manner with the inner wall in the crucible, then cooled and solidified at the outlet side of the crucible and continuously drawn, and the same amount of metal material as the drawn metal is supplied into the crucible. A plurality of slits are provided in a part of the height direction of the crucible, a cooling crucible having an entrance area larger than an exit area, and a periphery of the slit portion of the crucible. And a metal raw material supply means into the crucible, the light reflectance of the inner surface of the portion provided with the slit of the crucible is high, and the reflectance of the other portions is low. The present invention is a metal manufacturing apparatus, which is characterized in that a metal film is processed as much as possible, and a passage is formed so that a cooling medium flows in one direction in the crucible.

According to a second aspect of the present invention, in the first aspect of the present invention, cylindrical crucibles having different radii are arranged substantially concentrically, and are arranged on the inner peripheral side of the inner crucible and the outer peripheral side of the outer crucible. The gist is that the coil is arranged.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the magnetic flux shielding plate for controlling the intensity of the magnetic flux density in the space between the slit portion of the crucible and the molten metal is provided with a slit. It is intended to be arranged between the coil and the coil.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, there is provided an approximately concentric coil having irregularities in a radial direction, wherein the irregularities correspond to slit portions. It is a gist.

[0016]

[Action]

The present invention has the above-described configuration, and since a suitable number of radial slits are provided in a part of the crucible, a uniform high-frequency induced current can be caused to flow inside the crucible substantially along the circumferential direction of the crucible.

Since the pseudo Meisner effect is generated on the surface of the crucible and the surface of the metal raw material by the induced current, it is possible to float the metal raw material from the crucible in a non-contact manner while maintaining gravity, surface tension and balance. At the same time, melting of the metal material starts due to Joule heat loss of the induced current flowing on the surface of the metal material.

When supplying the metal raw material into the crucible, it is important not to make the molten metal surface unstable, but for this purpose, in the present invention, one end of the rod-shaped metal raw material is supported and is consumed by the crucible. It is conceivable to use a system that supplies only raw materials or a system that supplies a raw material in powder form.

In the present invention, the working coil is arranged only in the slit portion of the crucible, and the working coil is not arranged near the upper end and the lower end of the crucible. Can be coagulated along.

Note that the direction in which the solidified metal is pulled out is not necessarily limited to the direction in which gravity acts, but if this direction is assumed, the manufacturing apparatus can be simplified. Further, when changing the shape of the metal to an arbitrary shape, the shape of the exit of the crucible is generally close to the shape of the product, so that the entrance area of the crucible needs to be larger than the exit area. If a metal material is supplied to the gap between the inner and outer crucibles using the apparatus of the second aspect of the present invention, pipes can be manufactured.

The crucible used in the present invention preferably has the following features. The crucible surface corresponding to the melting portion of the metal has a high light reflectance, and the crucible surface corresponding to the solidified portion has a low light reflectance. Therefore, it is desirable to apply a process such as gold plating to the crucible surface in order to enhance the heating characteristics of the metal, and it is desirable to apply carbon or the like in order to enhance the cooling characteristics.

Having a high cooling capacity. Since the crucible is placed under a high heat load condition, a special method is required for the cooling method. In particular, it is more desirable that the inlet and outlet of the cooling water are arranged at different heights at the upper end or the lower end of the crucible so that the inside of the crucible can be linearly circulated.

Further, the magnetic flux density on the surface of the molten metal becomes non-uniform due to the effect of the slit, and as a result, irregularities occur on the surface of the molten metal. In order to eliminate the unevenness, it is necessary to control the intensity of the leakage magnetic flux from the working coil passing through the slit.

To control the leakage magnetic flux, a magnetic shielding plate usually used for EMC such as aluminum may be appropriately disposed between the slit and the working coil. Alternatively, a method is conceivable in which the distance between the surface of the molten metal and the working coil is larger or smaller in a specific direction having a slit than in other directions. For this purpose, a substantially concentric working coil whose concave or convex position has irregularities in the radial direction corresponding to the direction of the slit may be used.

[0025]

【Example】

Hereinafter, the present invention will be described based on an embodiment shown in FIGS. 1 to 3, reference numeral 11 denotes a crucible provided with an appropriate number of slits 12. The crucible 11 has a cooling structure. For example, a passage 15 is formed so that cooling water flows in one direction from an inlet 13 to an outlet 14 thereof. Further, the crucible 11 is formed such that the area on the entrance side is larger than the area on the exit side. Therefore, if the area on the inlet side is formed larger than the area on the outlet side, that is, if the area on the outlet side is smaller than the area on the inlet side, the area continuously decreases from the inlet to the outlet. Alternatively, as shown in FIGS. 1 and 2, the area may be reduced only at the intermediate portion.

By the way, the inner cross-sectional shape of the crucible 11 changes depending on the product shape to be manufactured. For example, when manufacturing a metal rod having a circular cross section, as shown in FIG. 1 or FIG. The inner cross-sectional shape on the outlet side is circular, and the working coil 16 is arranged in the slit 12 at the intermediate portion on the outer periphery of the crucible 11.

When a ring-shaped pipe is manufactured, for example, as shown in FIG. 2, cylindrical crucibles 11 having different radii are arranged substantially concentrically, and the inner crucible on the inner crucible and the outer crucible on the outer crucible are formed. The working coils 16 are arranged on the outer peripheral side of the crucible.
In the embodiment shown in FIG. 2, only the inner crucible is enlarged at the outlet side. However, if the area at the inlet side is larger than the area at the outlet side, the inner and outer diameters are changed according to the diameter of the pipe to be manufactured. The diameter of the crucible may be expanded or reduced, or only the outer crucible may be reduced in diameter.

FIG. 3 shows a structure capable of producing Ti metal substantially similar to FIG. 1 except that the productivity is high, and the cooling water is supplied to the crucible 11. Supplied from the bottom,
It has a structure of discharging from the upper part, so that it can cope with a higher heat load than that of the structure shown in FIG.

Although the metal material supply means is not shown, for example, the position of the molten metal in the crucible 11 is always measured by an appropriate method, and the level is kept constant.
What is necessary is just to operate the raising / lowering mechanism of a metal material, or to cut out a powdery raw material with a screw feeder.

Next, the result of actually manufacturing metal continuously using the crucible having the above configuration will be described. Part 1) Ti using the crucible constituting the device of the present invention shown in FIG.
The outline of a method for continuously producing metal is shown. Crucible entrance diameter is φ100mm, exit diameter is φ20mm,
Height is about 100mm.

The material of the crucible is copper having a purity of 99.95% or more, and a slit portion on an inner surface thereof is plated with gold having a thickness of 30 μm. Then, tap water was flowed at a linear flow rate of 5 m / s or more as cooling water. It is about 50 liters / min in terms of flow rate. Around the crucible, a working coil of φ10 mm capable of cooling inside was wound six times, and a high frequency current of 20 KHz was supplied at 2000 A. A base material of φ18 mm was inserted from below the crucible, and powdery Ti scrap was supplied from above the crucible. The whole crucible is placed in a vacuum container.

After approximately 5 minutes of current supply, part of the Ti was in a molten state, and after 10 minutes was in a completely molten state, and a state in which the molten Ti was floating in a crucible without contact was realized. Thereafter, the base metal was pulled down along the direction of gravity at a speed of 1 m / hr, thereby continuously producing Ti metal of φ19 mm.

(2) Ti using the crucible constituting the apparatus of the present invention shown in FIG.
The outline of the method for producing a metal is shown. The inner diameter of the entrance of the outer crucible is equal to that of the exit, φ10
0 mm. The outer diameter of the inlet of the inner crucible is φ50 mm, the outer diameter of the outlet is φ90 mm, and the height of the crucible is 100 mm. The outer periphery of the outer crucible and the inner periphery of the inner crucible are wound with a working coil having an outer diameter of 10 mm, which can be internally cooled, five times. Then, a high-frequency current of 50 KHz was applied to each coil at 2000 A. In addition, a hollow base material having an outer diameter of 98 mm and a thickness of 6 mm was inserted from below the crucible, and chip-like Ti scraps were supplied from above the crucible into the gap between the outer crucible and the inner crucible. After 15 minutes from the energization, the base material was pulled out at a speed of 1 m / hr. As a result, pipe-shaped Ti with an outer diameter of 99 mm and a wall thickness of 8 mm
Metal could be manufactured continuously.

(3) Using a crucible constituting the apparatus of the present invention shown in FIG. 3, Ti metal was continuously produced in the same manner as in Example 1). In the embodiment shown in FIG. 3, the number of turns of the coil is 6, the height of the crucible is 170 mm, and the melting capacity can be increased by a factor of 1.7. As a result of conducting a casting experiment using this crucible,
It was found that Ti metal pulled out at a high speed of 1.7 m / hr. In addition, the Ti produced in the above Examples 1) to 3)
The amount of increase in oxygen, hydrogen, and nitrogen after dissolution of the metal was 0.01% or less in total of these three elements, and it was found that contamination due to dissolution was negligible.

[0035]

【The invention's effect】

As described above, according to the present invention, particularly high melting point
It has an excellent effect that the purity of the highly reactive metal can be increased, and a high melting point and highly reactive metal having a shape close to a product can be continuously produced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a device of the present invention, in which (a) is a cross-sectional front view and (b) is a partial plan view.

FIGS. 2A and 2B are schematic explanatory views of the apparatus of the present invention, wherein FIG. 2A is a cross-sectional front view and FIG. 2B is a partial plan view.

FIG. 3 is a schematic explanatory view of the device of the present invention, and is a front view showing a section.

FIG. 4 is a conventional explanatory diagram.

[Explanation of symbols]

 11 Crucible 12 Slit 13 Inlet 14 Outlet 15 Passage 16 Working coil

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B22D 11/00-11/22

Claims (4)

(57) [Claims] 1. A metal raw material supplied into a cooling crucible is once induction-heated and melted by a high-frequency current applied to a coil disposed on an outer periphery of a slit portion provided in a part of the crucible in a height direction, and melted in the crucible. At the outlet side of the crucible, and then continuously drawn by cooling and solidifying at the outlet side of the crucible.The same amount of metal material as the drawn metal is supplied to the crucible for continuous production of metal. A device to be used, wherein a plurality of slits are provided in a part of the crucible in the height direction, a cooling crucible having an entrance area larger than an exit area, and a coil arranged around the slit portion of the crucible. A means for supplying a metal material into the crucible, wherein a metal coating is applied to increase the light reflectance of the inner surface of the portion provided with the slit of the crucible and reduce the reflectance of the other portions. Both metal manufacturing apparatus characterized by cooling medium constituted the passage so as to flow through the crucible in one direction. 2. The crucible according to claim 1, wherein inner cylindrical crucibles having different radii are arranged substantially concentrically, and coils are arranged on the inner peripheral side of the inner crucible and the outer peripheral side of the outer crucible. Metal manufacturing equipment. 3. A magnetic flux shielding plate for controlling a magnetic flux intensity in a space between a slit portion of a crucible and a molten metal is disposed between the slit and the coil. Metal manufacturing equipment. 4. The metal manufacturing apparatus according to claim 1, wherein the coil is a substantially concentric coil having irregularities in the radial direction, and the positions of the irregularities correspond to the slits.