JPH0659543B2 - Casting method and casting apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a casting method and a device therefor in which a molten metal treatment step in a final stage before casting is improved.

[Prior Art] Conventionally, when casting various working metals, it has been attempted to remove foreign matters in the molten metal by filtering with a filter such as a ceramic filter. An example of this type of casting method is disclosed, for example, in JP-A-51-142162.
No.

[Problems to be Solved by the Invention] However, even if the molten metal is filtered by a filter or the like, there is a problem that foreign matter is mixed into the molten metal again immediately before the casting mold. In particular, oxides and degassing residues are mixed from outside air in contact with the molten metal, resulting in insufficient purity of the ingot, or gas defects in the ingot. There was a problem.

In addition, the conventional method of preventing foreign matter from entering by filtration has a problem that a turbulent flow is generated in the molten metal after the filtration and the turbulent flow causes foreign matter to be more easily caught.

Therefore, an object of the present invention is to provide a casting method and an apparatus therefor capable of reliably preventing foreign matter such as oxides or gases from being mixed.

[Means for Solving Problems] In the casting method of the present invention, the molten metal is first filtered by a filter. Next, the mold part is connected to the surface of the filter opposite to the side to which the molten metal is supplied, the contact with the outside air is cut off in the space between the filter part and the mold part, and casting is performed in that state. It is characterized by

Further, in the casting apparatus of the present invention, a filter for filtering the molten metal and a space on the opposite side of the filter to the side where the molten metal is supplied form a space isolated from the outside air between the filter and the filter. And a mold part connected as described above.

[Operation] In the present invention, the latter stage of the filter, that is, the space between the filter and the mold portion is filled with the molten metal, and therefore, the casting is performed in a state where the contact between the molten metal and the outside air is cut off, and thus the filter is In the latter stage, the molten metal does not come into contact with the foreign matter generation source until it becomes an ingot, and no turbulent flow occurs in the molten metal located in the latter stage of the filter.

[Description of Embodiments] An embodiment of the present invention will be described below with reference to the drawings.

The accompanying drawings are vertical sectional views showing the outline of a casting apparatus according to an embodiment of the present invention. Molten metal 2 is stored in the molten metal tank 1. A tapered through hole 1a is formed at the bottom of the molten metal tank 1, and a stopper 3 capable of closing the through hole 1a is arranged in the molten metal tank 1. The stopper 3 is provided in order to adjust the supply speed of the molten metal 2, and when the molten metal 2 is made to flow down from the molten metal tank 1, it is separated from the through hole 1a, while the stopper 3 Through-hole 1 when stopping the supply
Moved to close a.

Further, the conduit 4 forming the through hole 1a extends downward from the molten metal tank 1, and the conduit 4 is inserted into the ceiling plate 5a of the filtering section 5 arranged below. In this embodiment, the joint between the top plate 5a and the conduit 4 is sealed so that gas and liquid do not leak to the outside from the joint.

A ceramic filter 6 as a filter is attached to the lower end of the filtering unit 5. In addition, a heating device 7 is arranged in the vicinity of the filtering portion 5, that is, in the vicinity of the surface of the ceramic filter 6 on the side where the molten metal 2 is supplied,
It is configured so as to prevent cooling in the filter unit 5.

Below the ceramic filter 6, a mold part 8 is connected. The mold portion 8 has a tubular portion 9 joined to the ceramic filter 6, and a cooling device 10 is attached around the tubular portion 9. That is, the molten metal 2 that has been filtered below the ceramic filter 6 by the cooling device 10.
Is cooled and solidified to form an ingot 11.

By the way, between the ceramic filter 6 and the mold part 8, a space sealed by the ceramic filter 6, the tubular part 9 and the ingot 11 is formed, and the space is filled with the filtered molten metal 2. Become. Therefore, the molten metal 2 filtered by the ceramic filter 6 is prevented from coming into contact with a foreign matter mixture generation source such as the atmosphere and turbulent flow is not generated.

In order to cool the ingot 11, cooling showers 13, 13 ... Are arranged in the subsequent stage of the casting mold portion 8. Further, although not shown in particular, cooling rollers 13, 13 ... Ingot 1 obtained by casting
1 is continuously sent out.

In the casting apparatus of the embodiment shown in the drawings, first, the molten metal tank 1
The molten metal 2 is filled inside. After that, the stopper 3 is separated from the through hole 1a as shown in the drawing, so that the molten metal 2 is caused to flow down into the filtering portion 5 and the inside of the filtering portion 5 is filled with the molten metal 2. In this state, the filtration unit 5
The molten metal 2 is heated by means of a heating device 7 arranged around it, thereby preventing the molten metal 2 from cooling. Therefore, it is possible to prevent the reduction of the filtration rate in the ceramic filter 6.

Then, the molten metal 2 is filtered by the ceramic filter 6 to remove foreign matters contained in the molten metal 2.

By the way, in the space formed on the lower side of the ceramic filter 6, contact of the filtered molten metal 2 with a foreign matter generation source such as air is prevented. In this state, continuous casting is performed in the mold part 8.

Therefore, in the apparatus and method of this embodiment, the ingot 11 containing no foreign matter can be obtained since the filtered molten metal 2 is immediately cast without contacting the foreign matter generation source.

Further, since the filtered molten metal 2 is filled in the closed space formed below the ceramic filter 6, as long as casting is continued in that state, turbulent flow in the filtered molten metal 2 can be prevented, It is possible to more effectively prevent the inclusion of foreign matter.

In addition, it is preferable that the top plate 5a of the filtration unit 5 has another conduit 14
It is possible to effectively remove the gas and the like generated in the molten metal 2 by forming the above and connecting the conduit to a pressure reducing means such as a vacuum pump. That is, generally, in the process of forming the ingot 11, the gas component contained in the molten metal 2 tends to be generated as bubbles, and the bubbles pass through the ceramic filter 6 and reach the ceiling of the filtration unit. Board 5
It is possible to reach a and discharge by the above-mentioned decompression means.

Next, concrete experimental results using the casting apparatus shown in the drawings will be described.

A ceramic filter containing alumina as a main component and having an average pore diameter of 0.8 mm was used as the filter 6, and tough pitch copper having a cross section of 150 mm square was continuously cast. At this time, a vacuum pump was connected to the upper part of the filtration unit 5 to exhaust air bubbles generated during casting. Further, in order to prevent the reduction of the filtration rate in the ceramic filter 6, the heating device 7 is used as in the above embodiment.
Thus, the molten metal 2 was heated on the supply side of the ceramic filter 6.

The ingot thus obtained was hot-rolled, then wire-drawn, stripped and intermediate-annealed, and drawn to a diameter of 0.03 mm.

For comparison, wire drawing was performed using the same material by the conventional continuous casting method without providing the ceramic filter 6 and the heating device 7.

As a result, according to the method of the present invention, compared with the conventional method,
The average weight of wire drawn per wire breakage increased by about 3 times.

[Effects of the Invention] As described above, according to the present invention, the molten metal is filtered by the filter, and the mold portion is connected to the surface of the filter opposite to the side to which the molten metal is supplied. Since casting is performed with the space between the mold part and the outside air being cut off, that is, because it is filtered by the filter immediately in front of the mold part, foreign matter that cannot be prevented by normal filtration with a simple filter is surely mixed. Can be prevented. Also, since the filter and the mold part are connected,
Turbulence due to pouring occurs only on the supply side of the filter,
No turbulent flow is generated between the filter and the mold portion, it is possible to prevent foreign matter from being entrained, and more reliably prevent foreign matter from entering.

It should be pointed out that the present invention can be generally used for manufacturing ingots for processing various metal foils, fine wires, and the like.

[Brief description of drawings]

The drawings are vertical sectional views showing the outline of an embodiment of the present invention. In the figure, 2 is a molten metal, 6 is a ceramic filter,
Reference numeral 7 indicates a heating device, and 9 indicates a mold part.

Claims (4)

[Claims] 1. A molten metal is filtered by a filter, a mold portion is connected to a surface of the filter opposite to a side to which the molten metal is supplied, and a space between the filter and the mold portion is exposed to the outside air. In a casting method in which casting is performed with the contact broken, in the mold part, bubbles generated when the molten metal solidifies are forcedly discharged through a filter on the side where the molten metal is supplied. Yes, the casting method. 2. The casting method according to claim 1, wherein the molten metal is heated in the vicinity of the filter. 3. A filter for filtering molten metal, and a filter connected to a surface of the filter opposite to a side to which the molten metal is supplied so as to form a space isolated from the outside air. In the casting apparatus including the mold part, a means for forcibly discharging the bubbles generated when the molten metal solidifies in the mold part is supplied through the filter on the side where the molten metal is supplied. Characteristic casting equipment. 4. The casting apparatus according to claim 3, wherein heating means is provided near the filter.