JP2928367B2 - Apparatus and method for casting casting material - Google Patents

Description

The present invention relates to an apparatus and a method for casting a casting material such as a metal, and particularly to a casting method for a metal material having extremely high temperature activity such as titanium or a titanium alloy. It is suitable for application to a casting apparatus and a casting method thereof.

b. Conventional technology Metallic materials such as titanium and titanium alloys are extremely active at high temperatures, react with active gases, and in the molten state, most refractories (oxides, carbides, nitrides, graphite, etc.). ) Reacts with this type of dissolved metal.
For this reason, a water-cooled metal crucible that does not easily react with the molten metal (molten metal) can be used as the crucible for melting titanium. Specifically, a casting apparatus that melts a copper crucible and uses a high-frequency induction heating coil as a heating means has been conventionally proposed.

FIG. 8 shows a main part of a conventional apparatus of this kind. In the figure, reference numeral 1 denotes a water-cooled copper crucible having a bottomed cylindrical shape, and 2 denotes a cylindrical side wall 1a of the crucible 1. , A cooling water passage formed inside the crucible 1, and a casting (made of metal such as titanium) material (molten metal). A plurality of slits (not shown) extending radially in the radial direction are formed in the above-mentioned crucible 1, and the casting material 4 is induction-heated and melted by the high-frequency induction heating coil 2 through these slits. It has become.

Thus, when the casting material 4 is put into the copper crucible 1 and is melted by induction heating with a high-frequency induction heating coil in a vacuum atmosphere, the melted casting material is subjected to the action of the electromagnetic force as shown in FIG. The molten metal 5 is formed without contacting the inner surface of the metal. Therefore, the molten state of the casting material 4 is maintained without reacting with the crucible 1. Then, after sufficient refining and degassing are performed in this state to improve the quality of the molten metal 5, the axis of the crucible 1 is inclined from the vertical direction to the horizontal direction, so that the molten metal 5 in the crucible 1 is tilted. Was poured into a predetermined mold (not shown) to perform casting.

c. Problems to be Solved by the Invention In the conventional casting apparatus and the casting method using the apparatus as described above, the molten metal 5 is poured into the mold while the crucible 1 is tilted. As a result, the temperature drops during the injection of the molten metal 5. In such a case, there is a problem that a difference in temperature of the molten metal 5 occurs between the start and the end of the casting of the molten metal 5, and a high quality cast product cannot be obtained.

When the crucible 1 is tilted, it is necessary to cut off the power supply to the high-frequency induction heating coil 2.
Therefore, there is a problem that the molten metal 5 contacts the inner surface of the crucible 1 and a considerable amount of the solidified casting material 4 remains in the crucible 1 in an attached state.

The present invention has been made in view of such circumstances, and has a purpose of instantly casting a molten metal in a crucible into a mold without lowering the temperature while having an extremely simple configuration. It is an object of the present invention to provide a casting material casting apparatus and a casting method capable of reducing the amount of solidified casting material remaining inside the crucible as much as possible.

d. Means for Solving the Problems In order to achieve the above object, in the casting material casting apparatus according to the present invention, there are provided: (a) a cylindrical side wall having a plurality of slits extending radially in a radial direction; A metal crucible formed by dividing a portion and a bottom wall portion on which a casting material is placed; (b) a high-frequency induction heating coil disposed so as to surround a cylindrical side wall portion of the crucible; c) a drive mechanism for separating the bottom wall of the crucible from the cylindrical side wall, and (d) a mold disposed vertically below the bottom wall of the crucible. .

Further, in the casting method of the casting material according to the present invention, by accommodating the casting material in a metal crucible and energizing the high-frequency induction heating coil, the plurality of slits formed in the cylindrical side wall portion of the crucible are used. The casting material is melted by induction heating, and thereafter, the bottom wall portion of the crucible is separated from the cylindrical side wall portion under a state where the electromagnetic force in the direction toward the axis of the crucible is acting on the molten metal. By doing so, the molten metal is instantaneously dropped vertically downward and poured into a mold.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7.

FIGS. 1 to 5 show a first embodiment of a casting material pouring apparatus according to the present invention. In this embodiment, a cooling type crucible 10 called cold crucible is used. I have. This crucible 10 does not react with high-temperature active casting materials such as titanium and titanium alloy,
As shown in FIG. 1 and FIG. 3, a cylindrical wall portion 11 and a bottom wall portion 12 disposed at a lower end of the cylindrical side wall portion 11 are made of copper having high thermal conductivity. It is composed of The cylindrical side wall 11 and the bottom wall 12 are divided so as to be separable from each other, and a plurality of slits 13 radially extending in the radial direction are formed in the cylindrical side wall 11 at equal intervals. ing. Note that these slits 13 are formed parallel to each other from the upper end surface of the cylindrical side wall portion 11 to the vicinity of the bottom wall portion 12, whereby the cylindrical side wall portion 11 of the crucible 10 is formed as shown in FIGS. As shown in the figure, a plurality of fan-shaped segments 14 constitute substantially one cylindrical portion. Around the cylindrical side wall 11 of the crucible 10, a plurality of turns of a high-frequency induction heating coil 15 are provided so as to surround the side wall 11 at a slight distance from the outer periphery thereof as shown in FIG. They are arranged concentrically.

Further, as shown in FIG. 4, a single slit 16 extending from the outer periphery to the center is formed in the side wall portion 12 of the crucible 10, and a small-diameter opening 17 is provided in the center portion.
Thus, the bottom wall 12 is configured so that an induced current flows in a direction indicated by an arrow a in FIG.

Further, cooling water passages (not shown) are provided inside the cylindrical side wall portion 11 and the bottom wall portion 12, respectively.
Inlet pipe 18 and outlet pipe 19 for cooling water
The crucible 10 is configured to be cooled by cooling water flowing sequentially through the crucible 10.

Further, the apparatus of the present example is provided with a drive mechanism 20 for rotating the bottom wall portion 12 of the crucible 10. As shown in FIG. 4, the drive mechanism 20 includes a pair of support substrates 21a and 21b, and a slide plate 23 having a notch 22 is provided between the support portions 21a and 21b. I have. That is, as shown in FIGS. 4 and 5, the guide plate 24 is attached to one support substrate 21a.
Are fixed by welding, and a forked tip portion 23a of a slide plate 23 is slidably sandwiched between the guide plate 24 and the slide plate 23 is an operating rod of an actuator 25 mounted on the other support substrate 21b. It is configured to slide at 25a in the direction of arrow b in FIG.

On the other hand, stainless steel cooling water pipes 30, 31 are connected to the copper cooling water inlet pipe 18 and outlet pipe 19 connected to the bottom wall portion 12 of the crucible 10 via insulating plates 28, 29, respectively. The bent portions 30a, 31a of these cooling water pipes 30, 31 are arranged in a straight line on the same axis, facing in opposite directions. And these bent parts 30a,
The tip of 31a is penetrated by the pair of support substrates 21a and 21b, and is supported by bearings 32 and 33 so as to be rotatable around its axis. Further, these bent portions 30a, 31a are connected to cooling water pipes 36, 37 via rotary joints 34, 35, respectively.

Further, one engagement pin 38 is fixedly provided at the joint of the bent portions 30a, 31a of the cooling water pipes 30, 31 by welding or the like. The engagement pin 38 is disposed on the movement locus of the notch portion 22 of the slide plate 23, and is normally used (at the bottom wall portion 12).
Is arranged as the bottom of the cylindrical side wall portion 11), the engagement pin 38 is engaged with the slide plate 23 so as to be held in a state where the rotation of the bottom wall portion 12 is prevented. ing.

Next, a method of casting a casting material (for example, a titanium alloy or the like) using the above-described casting apparatus will be described.

First, the crucible 10 is placed in an area surrounded by the high-frequency induction heating coil 15, and the casting material 40 is placed on the bottom wall 12 of the crucible 10.
Is placed. After that, a high frequency current (Jo) is supplied to the high frequency induction heating coil 15. Accordingly, the magnetic flux (B) generated by the high-frequency current (Jo) acts on the casting material 40 through the slit 13 of the cylindrical side wall 11 of the crucible 10, and the induced current (Je) flows through the casting material 40. As a result, the casting material 20 is heated by Joule heating and melted to form a molten metal (molten metal) 41. At this time, an interaction between the induced current (Je) flowing on the surface of the molten metal 41 and the magnetic flux (B) generates an electromagnetic force (F) in the molten metal 41, and the direction of the electromagnetic force (F) is determined by Fleming's left-hand rule. The direction is toward the axis of the crucible 10 (see FIG. 1). Accordingly, since the electromagnetic force (F) acts as a force for separating the molten metal 41 from the inner surface of the crucible 10, the contact between the molten metal 41 and the crucible 10 is cut off. Then, due to the surface tension, the molten metal 41 is placed in a crucible as shown in FIGS.
In the cylindrical side wall portion 10 of FIG. 10, it is in a state of being bulged upward in a spherical shape.

Under such a condition, the actuator 25 of the drive mechanism is operated when the molten metal 41 has reached the optimal pouring temperature.
Along with this, the slide plate 23 is slid in the direction of the arrow b in FIGS. 4 and 5 by the operating rod 25a of the actuator 25, and when the notch 22 of the slide plate 23 matches the engagement pin 38, the crucible is moved. The bottom wall portion 10 of FIG. 10 is rotated in the direction of arrow c in FIG. 3 around the axis of the bent portions 30a and 31a of the cooling water pipes 30 and 31. At this time, the molten metal 41 on the bottom wall portion 12 is tilted downward while being swung downward in the direction of arrow c in a lump, but the molten metal 41 is cylindrical due to the electromagnetic force (F) acting on the molten metal 41. It is inclined without contacting the side wall 11.
Then, when the bottom wall portion 12 is tilted to a certain degree, the molten metal 41 is instantaneously dropped vertically downward by its own weight and injected into the mold 42 immediately below.

According to the casting method using the casting apparatus of the present embodiment, the molten metal 41 of the casting material 40 is quickly dropped from the crucible 10 without contacting the cylindrical side wall portion 11, so that the molten metal 41 is melted into the cylindrical side wall portion 11. It is unlikely that metal adheres and remains, and a small amount of casting material remains on the side wall portion 12. Therefore, the yield of casting is very good.

In addition, since the molten metal 41 is instantly cast into the mold 42, the casting operation can be reliably performed without generating a temperature difference between the start and the end of the casting, so that a high quality cast product is obtained. be able to.

In order to confirm such effects, specific experiments were performed under the following conditions, and the following results were obtained.

Specific examples (1) Material of casting material: pure titanium (2) Dimension of casting material (a) Outer diameter: 70mmφ (b) Height: 70mm (3) Weight of casting material: 1kg (4) Dimensions of cooling crucible (B) Inner diameter: 7.5mmφ (b) Height: 150mm (c) Bottom wall outer diameter: 7.3mmφ (d) Bottom wall thickness: 10mm (5) High frequency heating conditions (a) Frequency: 10KHz ( B) Output: 30KW (c) Heating time: 6 minutes (6) Experimental results (a) Most of the molten titanium was instantaneously dropped and cast into a mold.

(B) Pure titanium was scarcely present on the inner peripheral surface of the crucible, and a small amount of pure titanium remained on the bottom wall.

(C) The cast product obtained was of good quality.

FIGS. 6 and 7 show a second embodiment of the present invention, in which the bottom wall 12 of the crucible 10 is constructed in a sliding manner.

That is, in this example, as clearly shown in FIG.
The copper inlet pipe 18 and the outlet pipe 19 provided on both sides of the slit 12 are connected to stainless steel cooling water pipes 30 and 31 via insulating plates 28 and 29, respectively. Actuator 2 on 31,
5 operating rods 25a are integrally connected, and this operating rod 32a
Is operated in the direction of arrow d to slide the bottom wall portion 12 in the horizontal direction (the direction of arrow d in FIG. 6) to separate it from the cylindrical side wall portion 11.
In FIG. 6, reference numeral 43 denotes a stainless steel flexible hose for supplying cooling water to the cooling water pipe 30.

Also in this case, as in the case of the above-described embodiment, the molten metal 21
Can be instantly dropped toward the mold 42,
The same operation and effect as those of the above-described embodiment can be obtained.

As described above, one embodiment of the present invention has been described, but the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

For example, in the above-described embodiment, the bottom wall portion 12 of the crucible 10 is configured to be a rotating type or a sliding type, but the rotating mechanism or the sliding mechanism of the bottom wall portion 12 may be changed to various driving configurations as necessary. It is possible. Also, in the case of adopting a rotary configuration,
The bottom wall 12 of the crucible 10 may be arranged so as to fit inside the cylindrical side wall 11.

e. Effects of the Invention As described above, according to the casting material pouring apparatus of the present invention, a cooling crucible made of metal having slits (a so-called cold crucible) is used. High-frequency induction heating of the casting material in the crucible can be performed without causing it.In addition, since the bottom wall of the crucible is separated from the cylindrical side wall and the molten metal is cast into the mold, casting is performed at the beginning and end of casting. The casting operation can be performed without causing a change in temperature, and thus a high quality cast product can be manufactured.

Further, according to the casting method of the casting material according to the present invention,
Casting material (melt) melted by high-frequency induction heating coil
Since the electromagnetic force in the direction toward the axis of the crucible is made to act, the molten metal becomes a single lump without contacting the inner peripheral surface of the crucible by this electromagnetic force, and a reaction occurs between the two. Can be prevented. Furthermore, since the bottom wall of the crucible is divided and driven to drop the molten metal vertically downward and cast it into the mold, the molten metal is also subjected to the electromagnetic force at this time, so that the molten metal is formed by the cylindrical side wall of the crucible. Without being in contact with the inner surface of the steel. Therefore, the casting of the molten metal can be performed in an unreacted state and at an ideal casting temperature. In addition, since the casting material does not contact the cylindrical side wall of the crucible, the casting material does not solidify and remain in this portion, and therefore,
The remaining amount of the casting material in the crucible after casting can be greatly reduced, and the yield can be improved.

[Brief description of the drawings]

1 to 5 show a first embodiment of the present invention. FIG. 1 shows a cooling type crucible (cold crucible).
2, FIG. 2 is a plan view of the same, FIG. 3 is a schematic view showing the configuration of the casting apparatus, FIG. 4 is a plan view of a drive mechanism of the bottom wall portion, and FIG. V line enlarged sectional view, 6th
FIGS. 7 and 8 show a second embodiment of the present invention. FIG. 6 is a schematic view showing the configuration of a casting device, FIG. 7 is a plan view of a drive mechanism of a bottom wall portion, and FIG. FIG. 2 is a sectional view of a crucible used in a conventional casting apparatus. 10: Water-cooled crucible (cold crucible) 11: Cylindrical side wall, 12: Bottom wall, 13: Slit, 14: Section, 15: High-frequency induction heating coil, 18, 19, 30 , 31,36,37 …… Cooling water pipe, 20 …… Drive mechanism, 22 …… Notch, 24 …… Slide plate, 25 …… Actuator, 25a …… Activating rod, 38 …… Engagement pin, 40 …… Casting material, 41… Molten, 42 …… Mold.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B22D 41/14 B22D 39/02 B22D 21/02 F27B 14/06 F27B 14/08

Claims (2)

(57) [Claims] 1. A metal crucible obtained by dividing a cylindrical side wall having a plurality of slits radially extending in a radial direction and a bottom wall on which a casting material is placed. (B) a high-frequency induction heating coil arranged to surround the cylindrical side wall of the crucible; (c) a drive mechanism for separating the bottom wall of the crucible from the cylindrical side wall; d) a casting mold disposed at a position vertically below the bottom wall of the crucible; and a casting material casting apparatus. 2. A method in which a casting material is accommodated in a metal crucible and a high-frequency induction heating coil is energized to induce heating of the casting material through a plurality of slits formed in a cylindrical side wall of the crucible. After melting, the bottom wall portion of the crucible is separated from the cylindrical side wall portion while the electromagnetic force in the direction toward the axial center of the crucible is acting on the melt, thereby vertically dissolving the melt. A casting method of a casting material, wherein the casting material is instantaneously dropped downward and poured into a mold.