JPS63251786A - Melting and casting device for metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal melting and casting apparatus using a crucible.

[Conventional technology]

Active metals, e.g. titanium, titanium alloys, etc.? :@ As a method for solving this problem, the cold cruzi pull method using a water-cooled split copper crucible has been known for a long time.

As shown in the perspective view of FIG. 7, the water-cooled divided copper crucible 2 used in this method has a plurality of water-cooled copper segments 7 divided in the circumferential direction, and between each water-cooled copper segment 7... It has a cylindrical shape made of sandwiched insulators 8. High frequency induction heating coils 3 are wound around the water-cooled divided copper crucible 2 at predetermined intervals.

The insulator 8 is made of CaF'2, for example, and prevents the generation of eddy currents due to the high frequency s field.

When a high-frequency current of, for example, 100 KHz is passed through the high-frequency induction heating coil 3, the material to be melted in the water-cooled divided copper crucible 2 is heated and melted, with almost no eddy current flowing through the water-cooled divided copper crucible 2.

When active metals such as titanium are melted by such a cold cruzi pull method, water-cooled divided copper crucible 2
As shown in FIG. 8, the solidified shell 19 of the material to be melted adheres to the inner wall of the material, and the molten metal 20 in which the material to be melted is dissolved.
This solidified shell 19 protects it. Therefore, it is possible to prevent contamination of molten metal due to elution of refractories, which is a problem when using a CaO crucible or the like.

Conventionally, the molten metal 2o is cast by tilting the water-cooled divided copper crucible 2 containing the molten metal 2o and casting the molten metal 2o into a mold 12 disposed below, as shown in FIG. This was done by pouring it in.

[Problem that the invention seeks to solve]

However, in the above-described casting method, the scum 24 floating on the surface of the molten metal 2o in the water-cooled dividing crucible 2
As shown in FIG. 9, the molten metal 20 flows into the lower mold 12, resulting in defects in the product.

Therefore, in order to prevent the scum 24 from flowing into the first
A method of pouring the bath molten metal 20 into the lower mold 12 from a nozzle 26 provided on the bottom wall of the tundish 25 via a mendish 25 made of an oxide such as CaO, as shown in FIG. It is being said.

However, according to this method, Tanditsh 25
There is a problem in that contamination occurs due to the elution of oxides that make up the water-cooled split copper crucible, which eliminates the advantage of using a water-cooled split copper crucible. 29
is a stone gun that opens and closes the nozzle 26 to prevent the inflow of scum 24.

On the other hand, metals other than active metals such as titanium, i.e. metals and alloys that can be melted in ordinary refractory crucibles (e.g. stainless steel,
Similarly, when melting carbon steel (carbon steel, soot alloy, etc.) in a refractory crucible and casting it, the scum floating on the surface of the molten metal in the crucible flows into the mold together with the molten metal, resulting in the product being damaged. There is a problem that defects occur.

Therefore, an object of the present invention is to melt and cast active metals such as titanium or alloys by the cold cruzi pull method using a water-cooled split copper crucible, in which scum floating on the surface of the molten metal in the crucible forms a mold. Another object of the present invention is to provide a metal melting/casting apparatus in which the molten metal in the crucible is not contaminated by elution of refractories. In the process of melting and casting metal or alloy using a normal refractory crucible, the scum floating on the surface of the molten metal in the crucible does not flow into the mold, and the molten metal in the crucible does not flow into the mold. An object of the present invention is to provide a metal melting/casting apparatus in which refractories are not contaminated by G discharge.

[Means for solving problems]

This invention provides a crucible whose bottom wall is made of the same metal as the metal to be melted, a heating mechanism for heating and melting the metal to be melted supplied into the crucible, and a heating mechanism for heating and melting the metal to be melted supplied into the crucible; The invention is characterized by comprising: a bottom wall opening mechanism for punching a hole in a portion of the bottom wall by heating and melting the bottom wall; and a mold disposed below the hole opening position in the bottom wall. It has the following.

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the invention, and FIG. 2 is a longitudinal sectional view thereof. FIGS. 1 and 2 show a crucible 4 consisting of high-frequency g induction heating coils 3 as a heating mechanism wound at irregular intervals, and an electron as a bottom wall opening mechanism disposed below the crucible 4. It consists of a gun 5, a deflection coil 6, and a mold 12 placed below the opening position of the bottom wall 9 of the crucible 4.

The water-cooled divided copper crucible 2 has a cylindrical shape consisting of a plurality of water-cooled copper segments 7 divided in the circumferential direction and an insulator 8 sandwiched between each water-cooled copper segment 7. . 1
0 is a water-cooled pipe that penetrates inside the water-cooled steel segment 7;
Cooling water flows from the upper part 10a to the lower part 10b as shown by the arrow.

The bottom wall 9 of the water-cooled divided copper crucible 2 is made of the same metal as the metal to be melted.

When a high frequency current of, for example, 100 KHz is passed through the high frequency induction heating coil 3, the metal to be melted (for example, an active metal such as titanium or an alloy thereof) in the crucible 4 is heated and melted.

A raw material hopper (not shown) is provided above the crucible 4 to supply the metal to be melted into the crucible 4 and to add an alloy material for composition adjustment.

Two deflection coils 6 are arranged at a predetermined interval on both sides below the center of the crucible 4, and an electron gun 5 is arranged on the side between the two deflection coils 6. The electron gun 5 is
An electron beam 11 is projected horizontally between two deflection coils 6. Horizontal electron beam 1 projected from an electron gun 5
1 is deflected vertically upward by the deflection coil 6 and projected vertically onto the center of the bottom wall 9 of the crucible 4 from below. In this way, the electron beam 11 dissolves the center of the bottom wall 9 and the solidified shell 19 deposited on the bottom wall 9 to open a vertical hole 13 .

At this time, in order to stably emit the electron beam 11 from the electron gun 5, the electron gun 5, the deflection coil 6, and the emitted electron beam 11 are connected to the 10-2T by a mechanism not shown.
It is preferable that both orr and υ be maintained at a high vacuum.

The arrangement position of the electron gun 5 is not limited to the horizontal direction of the deflection coil 6 described above. For example, by using deflection coils having different deflection angles, the electron gun 5 may be arranged at a position other than the horizontal direction of the deflection coils.

A mold 12 is arranged vertically below a hole 13 formed in the bottom wall 9 of the crucible 4, and the molten metal 20 in the crucible 4 is
It falls vertically into the mold 12 through the hole 13.

Note that the bottom wall 9 may have a water-cooled structure except for the area around the hole 13.

FIG. 3 is a longitudinal sectional view showing a second embodiment of the invention. As shown in FIG. 3, the apparatus of the second embodiment differs from the apparatus of the first embodiment only in the structure of the bottom wall of the water-cooled divided copper crucible constituting the crucible.

That is, the bottom wall 14 of the water-cooled divided copper crucible 2 is made of a water-cooled copper plate 23, and a circular plate 15 made of the same metal as the metal to be melted is fitted in the center thereof.

FIG. 4 is a longitudinal sectional view showing a third embodiment of the invention. As shown in FIG. 4, the apparatus of the third embodiment differs from the apparatus of the first embodiment in that the structure of the crucible is constituted by a normal refractory crucible 16 and the structure of the bottom wall.

The bottom wall 17 of the refractory crucible 16 is made of the same refractory as the refractory crucible 16, and a circular plate 18 made of the same metal as the metal to be melted is fitted in the center thereof.

Note that the bottom wall 17 of the refractory crucible 16 may be made of only the same metal as the metal to be melted.

The apparatus of the third embodiment is suitable for melting and casting metals other than active metals such as titanium, which are melted using, for example, ordinary refractory crucibles. 27 is a molten metal, and 28 is a solidified shell.

[For production]

Next, the operation of the device according to the first embodiment of the present invention will be explained.

The metal to be melted is heated in the crucible 4 for a predetermined period of time to be intoxicated, and then an alloy material is added to adjust the composition.

After the component adjustment is completed, as shown in FIGS. 1 and 2, an electron beam 11 is projected from the electron gun 5 to vertically melt the center of the bottom wall 9 of the crucible 4 from below to open a vertical hole 13. make a hole Furthermore, the solidified shell 19 at the opening position of the bottom wall 9
Drill a hole. As a result, the molten metal 20 in the crucible 4' falls through the hole 13 into the mold 12 disposed below and is cast into the mold 12. :.

At this time, the scum floating on the surface of the molten metal 20 never gets mixed into the mold 12, so that the cast product will never be defective.

Note that the heating mechanism for heating the metal to be melted in the crucible is not limited to the high-frequency induction heating coil.

That is, as a heating mechanism, as shown in FIG. An arc melting means may be used which melts the material by the heat of the arc generated between the material and the material.

Alternatively, a melting means such as plasma or electron beam may be used.

〔Example〕

Next, the present invention will be explained using examples.

An apparatus according to the first embodiment of the present invention having the following specifications as shown in FIGS. 1 and 2 was used.

Water-cooled divided copper crucible; Number of divisions: 24 segments, Inner diameter: 120mm φ, Height: 200 VTB.

High frequency induction heating coil: Inner diameter...180 thread φ, Applied frequency...100KH7゜ Applied output: 200 KW, Electron gun: Applied power -30KV.

Applied output: 60KW.

According to the above-mentioned apparatus, a titanium alloy 7K9 having a chemical composition of 6AA-4V-balance Ti and unavoidable impurities was produced.
When I solved the problem and poured it into the mold below, I was able to cast a good product.

Next, using the above-mentioned apparatus, nickel-based high alloy J Ky having the chemical composition shown in jXlN is melted and
A specimen of the present invention was obtained by casting.

On the other hand, using an ordinary refractory crucible and a high-frequency induction coil with the same dimensions as above, nickel-based highalloy 4 Ky having the chemical composition shown in Table 1 was melted under the same application conditions as above, and then CaO Comparative specimens were obtained by casting into the lower mold through a tundish made of oxides such as .

Table 1 Next, 7P was dissolved in the obtained specimens of the present invention and comparative specimens by a known electron beam button melting method, and the area index of inclusions floating on the surface was measured. Indicated.

As shown in FIG. 6, the inclusions in the specimen of the present invention are
This was the approximate amount of inclusions in the comparison specimen.

〔Effect of the invention〕

As explained above, according to the present invention, the scum that floats on the surface of the molten metal during melting in the crucible is not brought into the mold, and the molten metal is prevented from being brought into the mold by the refractory.
Since there is no contamination, the industrially useful effect of being able to cast clean cast products free of impurities can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a first embodiment of the invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a longitudinal sectional view showing a second embodiment of the invention, and FIG. 4 is a longitudinal sectional view showing the second embodiment of the invention. FIG. 5 is a vertical cross-sectional view showing the fourth embodiment of the present invention, FIG. 6 is a graph showing the area index of inclusions in a cast product, and FIG. 7 is a water-cooled divided copper crucible. and a perspective view showing a high-frequency induction heating coil, FIG. 8 is a longitudinal sectional view of a water-cooled split copper crucible, FIG. 9 is a sectional view showing an example of a conventional casting method, and FIG. It is a diagram. In the drawings, 1...metal melting/casting equipment;

Claims (4)

[Claims] (1) A crucible whose bottom wall is made of the same metal as the metal to be melted, a heating mechanism for heating and melting the metal to be melted supplied into the crucible, and a heating mechanism for heating and melting the metal to be melted supplied into the crucible; A bottom wall hole opening mechanism for opening a hole in a part of the bottom wall by heating and melting the hole, and a mold disposed below the hole opening position in the bottom wall. Metal melting and casting equipment. (2) The metal melting and casting apparatus according to claim (1), wherein only the portion of the bottom wall where holes are to be formed is made of the same metal as the metal to be melted. (3) The crucible is constituted by a water-cooled divided copper crucible and a high-frequency induction heating coil as the heating mechanism wound around the water-cooled divided copper crucible. ) or (2) above. (4) The bottom wall opening mechanism includes an electron gun and a deflection coil for deflecting an electron beam from the electron gun and projecting it onto the bottom wall. A metal melting/casting apparatus according to any one of scope items (1) to (3).