JPS61169139A - Continuous casting device - Google Patents

Abstract

PURPOSE:To obtain a long-sized metallic ingot having unidirectionally solidified structure without breakout by forming a casting mold into the construction in which one end projects into a molten metal and the other end contacts with a cooling structural body. CONSTITUTION:A graphite casting mold consisting of refractories of a good heat conductor is used for the casting mold 6 and one end thereof is projected to the molten metal 1 so that the mold 6 is heated by the heat of the molten metal. The solidified surface is thus maintained on the inlet side of the molten metal without using heating means and without overheating. The other end of the mold 6 is made into the construction in which said end contacts with the cooling structural body 5. The molten metal is unidirectionally solidified by heating the mold 6 on one side and cooling the same on the other with the above-mentioned construction, by which the casting structure having extremely large crystal grain size is obtd.

Description

[Detailed description of the invention] The present invention relates to a continuous metal casting apparatus.

In particular, it relates to a device that can easily achieve unidirectional solidification.

In continuous casting of metals, conventional equipment produces columnar crystals obtained by dendritic structures growing in the same direction.

It grows from the side wall of the mold toward the center of the casting, and equiaxed crystals often grow in the center. Further, foreign matter and the like accumulate inside the casting, causing many internal defects.

For this reason, during plastic working, when compressed in the direction of columnar crystal growth, some alloys may cause single grain boundary cracking, which is undesirable.

In order to solve this drawback,
A device that heats the mold and solidifies it at the mold outlet has been proposed, but it has two drawbacks: breakouts are likely to occur during operation. Additionally, a heater is built into the mold to heat the mold itself.
It was not a desirable structure.

In other words, the material requirements for manufacturing rods and the like as conductive materials for thin objects such as electric wires in equipment are as follows: 1. The material must have few internal defects such as foreign objects and pinholes.

2. It must be long and of uniform quality, with little segregation.

3. Columnar crystals should not grow toward the center of the rondo.

There is a need for a continuous casting apparatus that can obtain products that meet the following conditions, and that also has safety, which is a necessary item during casting.

The present invention satisfies the following two needs.

That is, it is a continuous casting apparatus in which one end of the mold protrudes into a molten metal bath and the other end is in contact with a cooling structure.

Furthermore, the following are provided as embodiments of the present invention.

The casting apparatus described above, wherein the material of the mold is a refractory material that is a good thermal conductor.

The casting apparatus described above includes a heat-retaining heating element provided between one end and the other end of the mold.

2. U-building device having a structure in which inert gas and/or neutral gas is blown into the mold wall surface from the molten metal bath side of the mold cooling structure.

The present invention will now be described in detail.

Metals to which the device of the present invention is applied include copper, gold, silver, aluminum, zinc, lead, soot, and alloys thereof.

In particular, those with good thermal conductivity are preferred.

One end of the mold of the present invention projects into the molten metal bath.
By making the mold protrude, the mold is heated by the heat of the molten metal. This makes it possible to maintain a solidified surface on the inlet side of the molten metal without using a separate heating means or overheating. At the same time, it enables unidirectional solidification and allows a cast structure with very large crystal grains to be obtained.

Furthermore, the other end of the mold is in contact with the cooling structure.

One-way solidification can be preferably performed by heating one end of the mold and cooling the other end.

At the same time, no molten metal is present at the mold outlet.

This enables continuous casting without any breakage.

In order to make the continuous casting apparatus described above more preferable, it is preferable to use a refractory material with good thermal conductivity as the material for the mold. For example, silicon nitride, silicon carbide, graphite, etc.

Furthermore, it is preferable to provide a heat-retaining heating element between one end and the other end of the mold so that the temperature of the mold is not influenced by the outside air. It is preferable to form the mold so as to surround the entire periphery of the mold.

Further, the structure is such that inert gas and/or neutral gas is blown into the mold wall surface from the molten metal bath side of the mold cooling structure.

This structure prevents segregation of the solidified metal and maintains a uniform temperature of the molten metal.

The gas serves at least to stir and mix the solution at the entrance of the molten metal to the mold. It is preferable that the structure allows charging from at least the inlet side of the mold rather than the part of the mold that is in contact with the cooling structure.

Furthermore, the casting apparatus used in the present invention may be one in which a mold is provided at the lower part of a melting furnace or a holding furnace, or one in which a mold is provided on a side wall of a melting furnace or a holding furnace.

41 Regarding the thickness of products suitable for use with the device of the present invention, products with a very large diameter are not suitable. For example, the diameter is 20m
The size is less than m. This is because the temperature of the mold is preferably within a range that can be transmitted to the molten metal or semi-solid metal in order to enable unidirectional solidification.

By implementing the present invention as described above, the following effects can be obtained.

(1) A long metal lump with a unidirectionally solidified structure can be obtained without the risk of breakout.

(2) It is possible to obtain a long metal lump that is free from foreign matter and pinholes.

(3) A unidirectionally solidified ingot with less segregation can be obtained.

(4) The surface of the ingot is extremely smooth.

(5) Due to unidirectional solidification, workability is extremely good.

(6) Since a long metal lump with large crystal grains can be obtained, it is suitable for manufacturing rondo as a material for thin conductive wires such as electric wires for equipment (for example, electric wires for audio equipment).

Example 1 The experiment was carried out using the apparatus shown in FIG.

The end of a pure copper rod with an outer diameter of 10° and 6 mm is placed 1 cm inside from the supply side of the molten metal (1) in a taraphite mold (6) having a hole of 11 mm diameter attached to the bottom side wall of the melting furnace (2).

50 kg of molten pure copper was placed in the furnace and maintained at 1250°C. Water was passed at a rate of 8 Q/min through the cooling structure (5) installed on the side opposite to the molten metal supply side, and the solidification position of the pure copper was set on the molten metal supply side in the mold.

Inject N2 gas (as shown in Figure 1) into the graphite mold.
4) and ejected into the molten metal while covering the surface of the casting rod (3). A working shell was created to stir the molten metal and eliminate variations in temperature and metal composition. Nao N2
A gas seal (8) was provided so that the gas was released only to the molten metal side.

The solidified rod was continuously pulled out using pinch rolls (7) at 33 mm/min.

The resulting pure copper was unidirectionally solidified and had extremely large crystal grains.

Example 2 When the apparatuses shown in FIGS. 2, 3, and 4 were used in the same manner as in Example 1, preferable unidirectionally solidified rods were obtained.

In addition, in FIGS. 3 and 4, a device equipped with a heat-retaining heating element (9) was used in order to reduce the influence of outside temperature.

[Brief explanation of drawings]

FIG. 1 shows the present invention applied to horizontal continuous casting. FIG. 2 shows a downward continuous casting apparatus. Third
Figures 1 and 4 show the embodiments of Figures 1 and 2,
It is equipped with a heating element for heat retention. (1) Molten metal, (2) Melting furnace, (3) Casting rod, (4) N2 gas inlet, (5) Cooling structure, (6) Graphite mold It is. −8=

Claims (4)

[Claims] (1) A continuous casting apparatus characterized in that one end of the mold protrudes into a molten metal bath and the other end is in contact with a cooling structure. (2) The continuous casting apparatus according to claim 1, wherein the material of the mold is a refractory material that is a good thermal conductor. (3) The continuous casting apparatus according to claim 1, characterized in that a heat-retaining heating element is provided between one end and the other end of the mold. (4) The continuous casting apparatus according to claim 1, characterized in that the continuous casting apparatus has a structure in which inert gas and/or neutral gas is blown into the mold wall surface from the molten metal bath side of the mold cooling structure. .