JP2012240050A - Device for casting columnar ingot and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for casting a columnar ingot capable of suppressing the generation of a shrinkage cavity and improving separability from tundish after casting, and a method of manufacturing the columnar ingot using the same.SOLUTION: The device for casting the columnar ingot includes a plurality of columnar molds, and the tundish whose bottom has a plurality of nozzles corresponding to the molds and which is brought into contact with and separated from a heat insulating formwork formed at an upper part of the mold. The heat insulating formwork of the mold is provided at each mold independently and has a heat insulating cylinder body adjoining a mold body, and an opening communication part guiding molten metal from the nozzle to the mold. The opening communication part includes a heat insulating lid overhanging the heat insulating cylinder body over the whole circumference.

Description

  The present invention relates to a method of simultaneously pouring and casting a plurality of molds, typically molds arranged in a matrix (matrix), to suppress the formation of shrinkage cavities and to separate them from the tundish after casting. TECHNICAL FIELD The present invention relates to a columnar ingot casting apparatus with improved properties and a columnar ingot manufacturing method using the same.

Conventionally, in the investment casting method (lost wax casting method) or the like, it is common to manufacture a master metal with high purity in advance and melt and cast it.
In investment casting, since the melting unit is small, it is necessary to prepare many master metals of a specific size. As a technique for casting such a master metal, a casting method has been proposed in which casting is simultaneously performed by pouring on a mold arranged in a matrix (matrix).
For example, in the simultaneous ingot forming apparatus for a plurality of ingots described in Patent Document 1, a communication runway is provided between a plurality of juxtaposed molds and a tundish for molten metal distribution having nozzle ports directed to the respective molds. It has a flat plate made of refractory material. In this method, since it is possible to cast simultaneously on a plurality of molds, there is an advantage that the casting time is short and the casting is uniformly performed on each mold so that there is no shortage of hot water.

Japanese Utility Model Publication No. 62-82150

As described above, the casting method in which the casting is simultaneously poured onto the molds arranged in a matrix (matrix) is effective for manufacturing the master metal.
On the other hand, according to the study of the present inventor, it has been found that the following problems cause the productivity to decrease.
When a large number of ingots are manufactured at the same time, the tundish that distributes the molten metal requires strength. Therefore, the tundish that receives the molten metal requires a refractory material that directly contacts the molten metal and a frame that reinforces it. In this case, since the tundish itself becomes a cooling body with respect to the molten metal, the molten metal in the hot metal after casting is deprived of heat by the tundish and solidifies before sufficiently supplying the molten metal into the mold ingot. As a result, the hot water does not act effectively and a shrinkage cavity is generated in the ingot. In the master metal in which the shrinkage nest is generated, the cutting powder enters the shrinkage nest at the time of cutting, which causes a defect when the melted redeveloped. In order to solve this, when the hot water is enlarged, the quality is not adversely affected, but a yield loss occurs.
In addition, if the diameter of the nozzle connected from the tundish to the mold is small, the nozzle may be blocked or narrowed by scum or refractory mixed in the molten metal from the furnace, and the molten metal may not enter the mold. If the nozzle diameter is simply increased, the remaining hot water of the tundish and the ingot are firmly connected, resulting in poor workability. Increasing the casting speed is effective for improving the ingot surface, but for that purpose it is necessary to increase the nozzle diameter, and in this case as well, the above problem occurs.

  An object of the present invention is to provide a columnar ingot casting apparatus and a columnar ingot manufacturing method using the same, in which the generation of shrinkage cavities is suppressed and separability from the tundish after casting is improved in view of the above problems. It is.

The present invention comprises a plurality of columnar molds, and a tundish that has a plurality of nozzles corresponding to the respective molds at the bottom, and the bottoms can be contacted and separated from a heat insulating frame provided at the top of the mold, The heat insulating frame of the mold is provided independently for each of the molds, and has a heat insulating cylinder that is continuous with the mold body, and an opening communication portion that guides the molten metal from the nozzle to the mold, and the hole communication The part is a columnar ingot casting device including a heat insulating lid part having an overhang shape on the entire circumference with respect to the heat insulating cylinder.
The present invention is particularly preferably applied when the bottom surface of the tundish is covered with a metal support frame.

  Further, in the method for producing a columnar ingot of the present invention using the above casting apparatus, the tundish is simultaneously poured onto the plurality of columnar molds in a state where the tundish is in contact with the heat insulating frame, and then the tundish is cast into the heat insulating frame. And separated from the nozzle between the heat insulating frames.

  According to the present invention, the occurrence of shrinkage can be prevented, which is effective for improving the ingot quality. Moreover, since it can prevent that a tundish and an ingot are connected firmly, it is effective with respect to the improvement of workability | operativity.

It is a schematic diagram which shows an example of the casting apparatus of this invention. It is a cross-sectional schematic diagram which shows an example of the casting apparatus of this invention. It is a cross-sectional schematic diagram which shows an example of the form of the contact part of the casting_mold | template and tundish applied to this invention. It is a cross-sectional schematic diagram which shows an example of the ingot to which this invention is applied. It is a cross-sectional schematic diagram which shows an example of the form of the contact part of the casting_mold | template and tundish of a comparative example. It is a cross-sectional schematic diagram which shows an example of the ingot to which the comparative example is applied.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an example of a casting apparatus applied to the present invention. 2 and 3 are schematic cross-sectional views showing an example of the form of the contact portion between the mold and the tundish applied to the present invention, respectively.

  First, as shown in FIG. 1, the columnar ingot casting apparatus of the present invention uses a plurality of columnar molds 5. The columnar ingot is advantageous for the shape of use of the master metal, can be manufactured at the same time, and is excellent in productivity. The mold shape may be a columnar shape, and the cross section may be rectangular or circular. A circular shape is preferable from the viewpoint of mold productivity.

  Moreover, as shown in FIG. 2, the tundish can apply the refractory 1 which receives a molten metal, and the frame 2 which reinforces it. This is because if the tundish is made of a single refractory, the strength is insufficient when many pieces are manufactured simultaneously. At this time, the bottom surface of the tundish is preferably covered with a metal support frame. The tundish has a plurality of nozzles 3 corresponding to individual molds at the bottom. The tundish frame 2 can be brought into contact with and separated from the heat insulating frame 4 provided on the upper part of the mold. This is because it is appropriate for the center of the nozzle opening to coincide with the center of the heat insulating frame. In addition, it is preferable that the heat insulating frame 4 and the tundish frame 2 can be in close contact with each other at the time of casting in order to prevent the molten metal from leaking.

The present invention is provided with a heat insulating frame 4 shown in FIG. 3 in order to suppress the generation of shrinkage cavities and improve the separation from the tundish after casting with respect to the casting apparatus having the basic configuration described above.
In FIG. 3, the heat insulation frame 4 with which the bottom of the tundish comes into contact is provided independently for each mold. This is because, if there is a member that forms another runner between the tundish nozzle 3 and the heat insulating frame 4, the solidified metal generated in that portion may impair the separability after casting.
The heat insulating frame 4 in the present invention has a heat insulating cylinder 4a continuous with the mold body and an opening communication portion 4c for introducing the molten metal from the nozzle 3 to the mold, and the mold communication side of the opening communication portion 4c is the heat insulating cylinder 4a. In contrast, a heat insulating lid portion 4b having an overhang shape on the entire circumference is provided. At this time, it is preferable that the diameter of the opening communicating portion 4 c be smaller than the diameter of the nozzle 3. Thereby, the operation | work which isolate | separates a tundish and an ingot becomes easy.
Further, the present invention provides the overhang-shaped heat insulating lid 4b so that the tundish frame 2 supporting the tundish refractory 1 and the molten metal in the mold do not come into contact with each other. Heat is not removed from the dish, and the heat insulating frame effectively acts on the ingot, so that a healthy ingot can be obtained. In addition, since the present invention can prevent clogging of the nozzle that leads from the tundish to the mold, even when the molten metal starts to solidify after being fully poured into the mold and the inside of the ingot is drawn, the heat insulating frame 4 The melt can be replenished from the tundish. For this reason, this invention can prevent effectively generation | occurrence | production of the shrinkage cavity in an ingot, without enlarging the heat insulation frame 4. FIG.
As the material of the heat insulating lid 4b and the heat insulating cylinder 4a, it is preferable to use a heat insulating material having high heat insulating performance. For example, a material made of silica fiber, ceramic fiber, alumina fiber or the like can be applied, and a soft material is desirable.

In the present invention, an ingot obtained by applying the entire overhang shape to the heat insulating lid portion 4b has the shape shown in FIG. With this shape, the remaining hot water connected from the inside of the tundish to the nozzle 3 and the ingot are hardly connected, so that the operation of separating the tundish and the mold after casting becomes easy. Here, as the overhang shape, a corner R shape or a taper shape can be appropriately selected in addition to the right angle shape as shown in FIG. 3 with respect to the heat insulating cylinder 4a.
In addition, the overhang shape of the heat insulation cover part 4b of this invention is a shape which narrows in a taper shape toward the open hole communication part 4c, Comprising: When the angle of the wall surface which forms an overhang shape approaches perpendicularly, it shows in FIG. The upper corner portion 9 of the ingot is connected along the overhang shape of the heat insulating lid portion 4b, and there is a strong possibility that the tundish and the ingot are strongly connected.
Therefore, it is preferable that the overhang shape is horizontal with the tundish bottom surface. Moreover, also when providing a taper, it is preferable to provide a tundish bottom surface and a horizontal part around the opening communication part 4c.

FIG. 5 is a schematic cross-sectional view showing an example of the form of the contact portion between the mold and the tundish as a comparative example. In the structure of FIG. 5 in which the heat insulation frame 4 has no overhang shape and does not have an overhang shape, the molten metal in the heat insulation frame 4 is cooled by the tundish frame 2, and the resulting ingot has a cross section as shown in FIG. . FIG. 6 is a schematic cross-sectional view of an ingot when the heat insulating frame does not have an overhang shape. Since the molten metal in the heat insulating frame 4 is cooled by the tundish at the top of the heat insulating frame 4, the molten metal cannot be sufficiently supplied into the ingot, and the shrinkage cavity 8 may be generated deep inside the ingot. .
In addition, the tundish and the ingot are cut at the portion of the nozzle remaining hot water 10, but if the nozzle diameter is increased, cutting by the ingot's own weight becomes impossible, and the work for dividing the tundish and the ingot becomes difficult. .
In addition, when the tundish and the ingot are divided by the weight of the ingot, it is necessary to perform the operation in a red hot state. Since it is oxidized, it has been confirmed that it adversely affects quality.

Hereinafter, a specific example of a manufacturing process of a columnar ingot using the casting apparatus of the present invention will be described with reference to FIGS. 1, 2, and 3.
First, the surface plate 7 on which the cooling metal 6 is arranged is prepared, and the hollow cylindrical mold 5 is set thereon. Next, a heat insulating material having the above-described heat insulating cylinder 4a and the opening communication portion 4c to be the heat insulating lid portion 4b is placed on the upper part of the mold 5. Thereafter, the tundish frame 2 is brought into contact with the heat insulating frame, and a molten metal is poured into the tundish 2 from another tundish (not shown), and is poured onto a plurality of columnar molds 5 at the same time.
After completion of casting, the tundish frame 2 is separated upward from the heat insulating frame 4.
At this time, as shown in FIG. 3, since the overhang shape is formed by the heat insulating lid portion 4 b, the ingot shape is as shown in FIG. 4, and the nozzle is separated from the nozzle by its own weight. . Finally, it can be extracted from the mold to obtain a columnar ingot.

1. 1. Tundish refractories 2. Tundish frame Nozzle 4. Insulation frame 4a. Insulated cylinder 4b. Insulation lid 4c. 4. Opening communication part Mold 6. 6. Cooling gold Surface plate 8. Shrinkage nest 9. Corner 10. Nozzle remaining hot water

Claims (3)

  A plurality of columnar molds, and a tundish having a plurality of nozzles corresponding to each of the molds at a bottom portion, the bottom portions being capable of contacting and separating from a heat insulating frame provided on the top of the mold, The frame is provided independently for each mold, and has a heat insulating cylinder continuous to the mold main body, and an opening communication portion for introducing the molten metal from the nozzle to the mold, and the mold communication side of the opening communication portion. Comprises a heat insulating lid portion having an overhang shape on the entire circumference with respect to the heat insulating cylinder, and a columnar ingot casting apparatus.   3. The columnar ingot casting apparatus according to claim 1, wherein a bottom surface of the tundish is covered with a metal support frame.   A columnar ingot manufacturing method using the columnar ingot casting device according to claim 1 or 2, wherein the tundish is simultaneously poured onto the plurality of columnar molds while being in contact with the heat insulating frame. Then, the tundish is separated from the heat insulating frame and separated from the nozzle between the heat insulating frames.