JPS6264455A - Continuous production of cast material - Google Patents

Abstract

PURPOSE:To safely and easily start continuous production of a cast material by attaching a bar-shaped elastic material of which the inside atmosphere is communicated with the atmosphere in an inert gas chamber contg. a crucible to said inert gas chamber and pulling up a molten metal from the crucible by a nozzle mold for casting. CONSTITUTION:The molten is contained in the crucible 2 having a high-frequency induction coil 4 disposed in the inert gas chamber1 and the nozzle mold 3 for casting is inserted therein. The top end aperture of the mold 3 is closed with a cap 7 and the inert atmosphere slightly higher than atm. pressure is maintained in the chamber 1 and in an elastic balloon 11 attached thereto via a conduit 12 by a vacuum evacuation pipe 5 and an inert gas introducing pipe 6. The cap 7 is then removed and a seed wire 10 is inserted into the mold 3 through the aperture thereof. The molten metal is attached to the top end of the wire and the wire is pulled up. The molten metal raised into the mold 3 is cooled and solidified and is continuously taken out as a bar-shaped cast material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for continuously manufacturing casting materials by passing molten metal through a nozzle mold under an inert gas atmosphere, and in particular, to The present invention relates to a method for continuously manufacturing the cast material, which is improved so that the work is safe and easy.

[Conventional technology]

Conventionally, copper alloys used as materials for lead frames of electronic components such as ICs and LSIs include Zr and Cr.
Since it contains metals that are easily oxidized, such as Ti, it is melted under an inert gas atmosphere, and in order to reduce the amount of post-processing, this molten metal is continuously shaped into a rod shape that is close to the shape of the final product. As a casting method, a casting method using a casting apparatus as shown in FIG. 2, for example, has been proposed (Japanese Patent Application Laid-Open No. 106648/1983).

This method involves using a water-cooled nozzle that is airtightly inserted into the chamber 1 from above the chamber 1 toward a crucible 2 that is made up of an airtight box-like body and is provided in a super-inert gas chamber 1. A method of continuously manufacturing a casting material from the molten metal M by introducing the lower end of the mold 3 into the molten metal M in the crucible 2 and cooling the molten metal M while pulling it up through the nozzle mold 3. A high frequency induction coil 4 for melting the metal and keeping it in a molten state is installed around the crucible 2, while a vacuum exhaust pipe 5 and an inert gas introduction coil are installed at the side of the chamber 1. A tube 6 is provided.

To start continuous casting using such a device, (1) First, the upper end opening of the nozzle mold 3 is closed with the cap 7, and then the valve 8 attached to the vacuum exhaust pipe 5 is opened to open the chamber 1. The interior is kept at a predetermined degree of vacuum, for example 1o-3~. −
After evacuation to 'Torr, active metals such as Zr, Ti, Cr and pure copper, which will be raw materials for casting materials, are charged into Lupo 2, and these metals are connected to high frequency induction coil 4.
(2) After the molten metal M is formed in this way, the valve 8 is closed, and the valve provided in the inert gas introduction pipe 6 is heated. 9 and introduce an inert gas such as argon gas from an inert gas supply (not shown) into the chamber 1 through the inert gas introduction pipe 6 to bring the inside of the chamber 1 to atmospheric pressure with the inert gas. (3) Next, remove the cap 7 that was blocking the upper end opening of the nozzle mold 3, and while the inert gas is being blown out from the opening, the seed wire 10 is Insert the nozzle mold 3 into the nozzle mold 3 from the upper end opening. Before the melt enters the molten metal, move the crucible 2 upward or pull down the nozzle mold 3 to allow the lower end of the nozzle mold 3 to enter the molten metal M, (5) thereby causing the tip of the seed line 10 is brought into contact with molten metal M,
After that, the pressure inside the chashiba 1 is increased again to a pressure slightly higher than atmospheric pressure, (6) and the series of operations of pulling the seed line 10 with the molten metal attached to the tip upwards is performed. Subsequently, the molten metal M that has risen inside the nozzle mold 3 along with the seed wire 10 is cooled and solidified to become a rod-shaped casting material, which is taken out from the upper end of the nozzle mold 3 to the outside of the apparatus.

[Problem that the invention seeks to solve]

In such a method for manufacturing a cast material, when starting operation according to the above procedure, there is a risk that air will enter the chamber 1 from the upper end opening of the nozzle mold 3 during the operations (3) and (4) above. In order to prevent this, in the operation (2) above,
It is necessary to make the pressure of the inert gas filled in the chamber 1 slightly higher than atmospheric pressure in advance. If it enters the molten metal at the lower end of the nozzle 3 during the operation of 4), there is a risk that the molten metal pushed by the pressure of the inert gas will rise inside the nozzle mold 3 and blow out from the opening at the upper end. If the pressure drops too much, the atmosphere will enter the chamber 1 through the upper opening, so it is necessary to maintain the inert gas pressure and carry out the above operation (4) without causing such trouble. The problem was that it was extremely difficult.

[Findings based on research]

Therefore, as a result of various studies to solve such problems, the present inventors have found that when the inert gas is blown out from the upper end opening of the nozzle mold 3 in the above operation (3), the pressure inside the chamber 1 increases. The pressure suddenly drops to near atmospheric pressure, and the pressure drops to such a level that the atmosphere is immediately mixed in from the upper end opening of the nozzle mold 3. Because it is difficult to stably maintain the appropriate pressure, the problems mentioned above are likely to occur.
I realized that such rapid fluctuations in pressure were caused by the fact that the entire chamber 1 was made of a highly rigid material, that is, a material that did not expand or contract at all due to changes in gas pressure. When a bag-shaped elastic body that communicates with the internal atmosphere is attached to the chamber, the pressure of the chamber 1 will gradually fluctuate due to the buffering effect of the elastic body, and in the operation (4), We have learned when it is possible to relatively stably maintain the pressure in chamber 1 at an appropriate level.

[Means for solving problems]

This invention was invented based on the above knowledge, and includes a lower end of a nozzle mold that is airtightly inserted into a crucible provided in an inert gas chamber from the -E side of the chamber. (a) in a method for continuously producing a casting material from the molten metal by entering the molten metal in a chamber and cooling the molten metal while pulling it through the nozzle mold; The present invention is characterized in that a bag-shaped elastic body through which the internal atmosphere is communicated is attached to the chamber to make the operation start-up operation in the manufacturing method safe and easy.

[Detailed description and operation of the invention]

As the bag-like elastic body used in the present invention, a narrow-mouthed bag-like body made of rubber, for example, a so-called rubber balloon is conveniently used, and this elastic body 11 is, for example, as shown in FIG. As shown in FIG. It's convenient.

The bag-shaped elastic body 1 attached to the chamber 1 in this way
1, while the inert gas is being released from chamber 1 to the outside, a part of the inert gas is held and sent out little by little into chamber 1, which prevents a sudden drop in the pressure inside chamber 1. In the operation (4) at the start of operation, a pressure suitable for performing the operation can be maintained for a relatively long period of time.

[Examples and effects based on the examples]

Next, the present invention will be explained by examples and in comparison with comparative examples.

FIG. 1 is a partial longitudinal sectional side view showing an example of a casting apparatus used in carrying out the present invention. In this figure, the same members as those constituting the conventional apparatus shown in FIG. The same reference numerals as those already used are used.

Diameter when filled with 1.5 atmospheres of air: Approx. 30
It swells up into a spherical shape, and when I leave it in the air, it takes about 1 hour until the air almost completely escapes from the swollen state and it collapses.
In the casting device shown in FIG. 1, in which a rubber balloon that takes 0.00 seconds is attached to the tip of a conduit 12 with a valve 13 protruding outward from the side wall surface of the conventional device shown in FIG. Please follow the start-up procedure described above.
First, the upper end opening of the nozzle mold 3 with an inner diameter of 1.0 c IRX length: 130 m is closed with a cap 7, and then the inside of the steel chamber 1 having an internal volume of 1.7 y + tl is opened using the vacuum exhaust pipe 5 with a diameter of 1.0 c IRX length: 130 m. After evacuating to a vacuum level of X 1O-4 Torr, pure copper 40 and 7 are charged into a graphite Luppo 2 with a capacity of 8.81, and this is heated and melted with a high frequency induction coil 4 to form a molten copper metal M. (2) Next, close the valve 8 and open the valve 9, and introduce argon gas into the chamber 1 from the inert gas introduction pipe 6, so that the inside of the chamber 1 is heated to 0.20 9; (3) Next, remove the cap 7 that was blocking the upper opening of the nozzle mold 3, and insert the pure copper seed wire 10 into the nozzle mold 3 90 seconds after argon gas starts blowing out from the opening. The pressure inside the chamber 1 is measured after insertion, and the pressure inside the chamber 1 is set to 0, which is a pressure where the argon gas is still being blown out sufficiently and there is no risk of atmospheric air entering through the opening. .05Kg
I measured the time it took to descend to the top of the island, and found that the pressure was 0.07 Kp/- and the time was 130 seconds.

The pressure inside the chamber 1 measured at the time when the seed wire 10 is inserted into the nozzle mold 3 is sufficiently close to atmospheric pressure, and it is equivalent to the force that pushes up the molten metal to a height of 90 mm in the nozzle mold 3. In addition, there is no risk of the molten metal blowing out from the upper end opening of the nozzle mold 3, and in the next operation (4),
As mentioned above, the time during which the lower end of the nozzle mold 3 could be melted and the molten metal could enter the port without causing the blowout of the molten metal or the mixing of the atmosphere was long.

In FIG. 1, reference numeral 14 indicates a pinch roll for pulling up the cast material.

Next, for comparison, operations (1) and -'2) of the above-mentioned operation start procedure were performed with the above-mentioned embodiment with the valve 12 closed and the internal atmosphere of the balloon IX and the chamber 1 cut off. After repeating exactly the same procedure, (3) remove the cap 7 that was blocking the upper end opening of the nozzle mold 3, and after argon gas starts blowing from the opening,
After a few seconds, the pure copper seed wire 1o is inserted into the nozzle mold 3 to measure the pressure inside the chamber 1 at that moment. When we measured the time it took for the pressure to drop from 0.05 Kp/- to a level where there was no risk of atmospheric air being mixed in, the pressure was 0.04 to 9/J.
The time was 10 seconds.

In the above comparative example, the pressure in the chamber 1 rapidly decreased and then the seed wire 10 was inserted into the nozzle mold 3 (C), and at the 9th point, the pressure was already 0.04 Ky as described above.
/-, and after that, this pressure decreases rapidly, so
Is the time for safely performing the next operation (4) as short as 10 seconds? Nozzle mold 3 70 seconds after
The pressure at the time of insertion is 0.1 Ky.
/ctft.

So, converting to the height of the molten metal at this pressure, the height is 130m.
Therefore, it was found that this pressure caused the molten metal to blow out.

From the above results, in the comparative example, the suitable time for the nozzle mold 3 to enter the molten metal is extremely short, and if the time is off, the molten metal is likely to blow out and the atmosphere is mixed in. In the embodiment of the present invention, after the inert gas is blown out, the pressure inside the chamber 1 decreases relatively slowly.1.
It can be seen that the suitable time for the nozzle mold 3 to enter the molten metal in the chamber 1 is extended in order to increase the temperature.

[Comprehensive effect of the invention]

As is clear from the above explanation, according to the present invention, the inert -7f energy in the chamber is set higher than the atmospheric pressure during the start-up work to the extent that the atmospheric pressure does not mix into the casting equipment. Since the pressure can be maintained at a sufficiently low level for a long time to the extent that the molten metal does not blow out of the equipment, troubles such as blowing out of the molten metal and air intrusion can be prevented during the start-up of the continuous manufacturing method for casting materials. Therefore, the above-mentioned work can be carried out safely and easily.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional side view showing an example of a casting apparatus suitable for carrying out the method of the present invention, and FIG. 2 is a partial longitudinal sectional side view showing a casting apparatus used in the conventional method. In the figure, 1...chamber, 2...crucible. 3... Nozzle mold, 4... High frequency induction coil. 5... Vacuum exhaust pipe, 6... Inert gas introduction pipe. 7...Cap, 8,9.13...Valve. 10... Seed line, 11... Balloon. 12... Conduit, M... Molten metal.

Claims (1)

[Claims] A lower end of a nozzle mold, which is hermetically inserted into the crucible, is inserted into the crucible in an inert gas chamber from above the chamber, and is introduced into the molten metal in the crucible through the nozzle mold. In the method of continuously manufacturing a cast material from the molten metal by cooling the molten metal while pulling it up, the manufacturing method comprises: attaching to the chamber a bag-shaped elastic body having an internal atmosphere communicating with the chamber; Safe start-up work,
The continuous manufacturing method of the cast material, characterized in that the method is characterized in that: