JPH08141706A - Device for casting metal and method therefor - Google Patents

Abstract

PURPOSE: To obtain a casting device and a casting method which can prevent the development of reverse segregation layer caused by the formation of air gap part, in a low cost and a simple constitution. CONSTITUTION: The air gap part 9 formed between the inner wall surface of a water cooled mold and the outer peripheral surface of a solidified shell in a mold is constituted so as to shut off from the atmosphere by action of a seal member 20. In the shut-off air gap part 9, an opened gas sucking hole 25 or an opened gas introducing hole is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for casting a metal such as an Al alloy or a Cu alloy, and in particular, by efficiently cooling the outer peripheral surface of the solidified shell in the mold, The present invention relates to a metal casting apparatus and a casting method for preventing re-melting of a solidified shell and reducing or preventing generation of a reverse segregation layer in a surface layer portion of an ingot.

[0002]

2. Description of the Related Art Al alloys and Cu alloys are cast into ingots by casting molten metal with alloy elements mixed and adjusted, and are then extruded, rolled or forged or otherwise subjected to plastic working, except in the case of casting. It is common to manufacture wrought materials such as plates and bars.

Of the above manufacturing processes, the casting process is an important process for determining the quality of the final product to be manufactured, and the continuous casting method, which is excellent in productivity and quality, is widely adopted. Has been done. In the casting of Al alloy, a semi-continuous casting method called DC casting method (Direct Chill Casting method) is carried out (for example, "Fundamentals and Industrial Technology of Aluminum Materials", edited by Japan Light Metal Association). This method will be described in more detail with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the DC casting method, and FIG. 2 is an enlarged view of the main parts of FIG. 1, wherein 1 is a water-cooled mold, 2 is cooling water, 3 is a cooling water inlet, 4 is a casting gutter, 5
Is a nozzle, 6 is a molten metal, 7 is an ingot, 8 is a bottom block, 9 is an air gap part, 10 is a solidified shell in a mold, 1
1 is a massy zone (semi-melting zone), 12 is a water pool, 1
3 shows floats, respectively.

In the DC casting method, the molten metal 6 in the casting trough 4 is
Is poured from a nozzle 5 through a float into a water-cooled mold 1 having a rectangular or circular pouring port (not shown) in plan view, and the molten metal 6 is solidified by cooling by the water-cooled mold 1 for comparison. Forming a solidified solidified shell 10 in the mold,
The ingot 7 is drawn downward while the upper outer peripheral surface of the ingot 7 formed below the solidified shell 10 in the mold is cooled by cooling water jetted from below the water-cooled mold 1. . Further, such a DC casting method is applied not only to Al alloys but also to Cu alloys and the like having excellent thermal conductivity. However, when a metal having good thermal conductivity such as an Al alloy or a Cu alloy is cast by the DC casting method as described above, there are the following problems.

As shown in FIG. 2, the molten metal 6 poured into the water-cooled mold 1 immediately contacts the inner wall of the water-cooled mold 1 and is cooled to a liquidus temperature or a solidus temperature or lower. The solidified shell 10 in the mold is formed. Solidified shell 1 in this mold
0 depends on the casting temperature, but is 10 m in the case of Al alloy
It is about m and is generally formed relatively thin.

By the way, the volume of metal generally shrinks during solidification and as the temperature decreases in the solid state. Particularly, in the case of Al alloy, the volumetric shrinkage rate during solidification is the same as that of steel materials. Very large compared to other metals. Further, Al alloys and Cu alloys have a coefficient of linear expansion approximately twice as high as that of steel materials, so that they usually shrink even when the temperature decreases after solidification. Therefore, the solidified shell 10 in the mold formed above the inside of the water-cooled mold 1 shrinks as it goes below the water-cooled mold 1 due to solidification and temperature decrease, and the outer peripheral surface of the solidified shell 10 in the mold is water-cooled. The mold is separated from the inner wall surface of the mold 1, and the contact with the water-cooled mold 1 is cut off. As a result, the air gap 9 as shown in FIG. 2 is formed between the solidified shell 10 in the mold and the water-cooled mold 1.

When the air gap portion 9 as shown in FIG. 2 as described above is formed, the air gap portion 9 which is an air layer has extremely poor thermal conductivity, so that the solidified shell 10 in the mold and the water-cooled mold 1 are separated from each other. Of the solidified shell 10 in the mold, the heat is no longer removed from the surface of the solidified shell 10 in the mold, and the solidified shell 10 in the mold does not further solidify. Further, as described above, the molten metal 6 in the casting trough 4 is constantly supplied from the nozzle 5 via the float 13 to the molten metal 6 side of the solidified shell 10 in the mold, so that the progress of solidification is stopped. The solidified shell 10 in the mold is always affected by heating from the molten metal 6. As a result, the solidified shell 10 in the mold is reheated, reheated to the solidus temperature or higher, and remelted to be in the same state as the massy zone 11.

The solidified shell 10 in the mold reheated to above the solidus temperature is in a semi-molten state in which the solid phase and the liquid phase are mixed, so that the liquid phase oozes out to the surface side of the solidified shell 10 in the mold. ,
A so-called perspiration layer is formed, and a reverse segregation layer in which the added alloy element is depleted or concentrated is formed on the surface layer portion of the solidified shell 10 in the mold. When such a phenomenon occurs, the ingot 7
The composition of the surface layer part of is different from the composition of the molten metal or the center part of the ingot, and the ingot 7 having a uniform composition cannot be obtained,
There is a problem that it becomes a surface defect of the ingot 7.

For this reason, in actual production, the surface layer portion of the ingot 7 after ingot casting is mechanically cut to remove the reverse segregation layer, but this causes a decrease in yield. Become. Whether or not the alloy components are depleted or concentrated in the reverse segregation layer is determined by the phase diagram in which each element forms Al. For example, Mg, Mn,
Elements such as Cu which form a eutectic phase diagram with Al are depleted, and elements such as Cr and Ti which form a peritectic phase diagram are enriched.

[0011]

As described above, in the DC casting method, the air gap 9 is formed due to the shrinkage of the solidified shell 10 in the mold, so that the recuperative heat of the solidified shell 10 in the mold and Remelting is promoted, which causes the reverse segregation layer to be generated in the surface layer portion of the ingot 7. Therefore, various techniques for preventing the formation of the reverse segregation layer have been proposed so far. For example, a method called an electromagnetic casting method has been proposed in "Handbook of Metals" (edited by The Japan Institute of Metals) and Japanese Patent Publication No. 46-37267. In this method, as shown in FIG. 3, a high-frequency coil 15 is arranged instead of the conventional contact-type water-cooled mold 1, and the molten metal 6 is held by the electromagnetic force generated by the high-frequency coil 15. Figure 3
In FIG. 1, reference numeral 16 denotes a cooling water jacket, and 17 denotes an electromagnetic shield ring, and other portions corresponding to those in FIG. 1 are designated by the same reference numerals.

With the structure shown in FIG. 3, since the water-cooled mold 1 is not used, the air gap 9 is not formed, and the generation of the reverse segregation layer can be suppressed. However, in this method, it is necessary to dispose the high-frequency coil 15 for generating an electromagnetic force, and in addition to this, expensive and large-scale equipment such as a power source is required, and the molten metal 6 is not removed. A sophisticated and complicated control mechanism and operation technology for holding by contact are required. Although it is possible to prevent the occurrence of the reverse segregation layer, since the molten metal 6 is held by the unstable electromagnetic force, unevenness is generated on the surface of the finally cast ingot 7, and the flatness It is difficult to obtain a high ingot 7, or a new problem is caused such that an oxide is wound around the surface of the ingot 7 due to the stirring effect of the electromagnetic force.

On the other hand, as another method, a so-called hot top method as shown in FIG. 4 has been proposed (for example, Japanese Examined Patent Publication Nos. 54-42847, 60-39456, and 61).
-1961). In this method, in order to reduce the period during which the air gap portion 9 is formed during casting as much as possible, in order to make the level of the molten metal in the water-cooled mold 1 shallow, a refractory header 18 is provided above the water-cooled mold 1. Is provided to facilitate low surface operation. However, this method requires the header 18 made of refractory processed with high precision, and the life of the header 18 is not always good. In an extreme case, the header 18 is replaced every time casting is performed. There is a problem of need. Further, when replacing the header 18, it is necessary to attach the header 18 to the upper portion of the water-cooled mold 1 with high precision while interposing a ring 19 for performing lubrication and the like, which requires extremely complicated work, resulting in workability. And productivity will deteriorate.

The present invention has been made in order to solve the technical problems in the prior art, and its purpose is to generate a reverse segregation layer in the surface layer of the ingot due to the formation of the air gap. To provide a casting apparatus and a casting method capable of reducing or preventing
Moreover, it is to achieve it with an inexpensive and simple structure.

[0015]

[Means for Solving the Problems] The casting apparatus of the present invention which achieves the above-mentioned object is to pour molten metal into a water-cooled mold to solidify the molten metal to form a solidified shell in the mold, and In the metal casting apparatus configured to draw the ingot downward while cooling the upper outer peripheral surface with cooling water jetted from below the mold, below the water-cooled mold and more than the cooling water jetting part. A seal member capable of contacting the lower outer peripheral surface of the solidified shell in the mold is provided above, and the seal member is brought into contact with the lower outer peripheral surface of the solidified shell in the mold, whereby the inner wall surface of the water-cooled mold and the The air gap portion formed between the outer peripheral surfaces of the solidified shells in the mold is configured to be shielded from the atmosphere, and (a) a gas suction hole opened in the blocked air gap portion, or (b) the shield. Was done The point is provided with a gas introducing hole opened on the earth gap and has a gist.

Further, the casting method of the present invention which has achieved the above object, is to use the above casting apparatus to bring the sealing member into contact with the lower outer peripheral surface of the solidified shell in the mold,
By blocking the air gap part formed between the inner wall surface of the water-cooled mold and the outer peripheral surface of the solidified shell in the mold from the atmosphere, (a) by sucking the atmosphere in the air gap part from the gas suction hole, Atmosphere is sucked into the air gap part from a slight gap between the water-cooled mold and the upper contact portion of the solidified shell in the mold, or (b) while introducing gas from the gas introduction hole into the air gap part,
The introduced gas is discharged from a slight gap between the water-cooled mold and the upper contact portion of the solidified shell in the mold, and the outer peripheral surface of the solidified shell in the mold facing the air gap is cooled while being cooled by suction atmosphere or introduced gas. The point is to do.

[0017]

The operation of the present invention will be described with reference to the drawings. FIG. 5 is an enlarged explanatory view of an essential part showing an embodiment of the casting apparatus of the present invention, and the same reference numerals are attached to the basic parts corresponding to those in FIG. In this casting apparatus, below the water-cooled mold 1 and above the cooling water jet nozzle 22 from which the cooling water 2a is jetted, a seal member 20 that can contact the lower outer peripheral surface of the solidified shell 10 in the mold is provided. The seal member 20 is provided so that it can be deformed by the action of pressure from the pressurizing chamber 21 and come into contact with the lower outer peripheral surface of the solidified shell 10 in the mold. Further, a gas suction hole 25 opening to the air gap portion 9 is provided between the water-cooled mold 1 and the pressurizing chamber 21.
In the figure, 26 is a vacuum pump, 27 is a flow control valve, 28 is a flow meter, and 29 is a gas suction pipe, all of which are provided in association with the gas suction hole 25.

A pressurizing fluid A such as a gas or a liquid is introduced into the pressurizing chamber 21 through an introducing pipe 30.
It is configured so that the inside can be pressurized to an arbitrary pressure. The seal member 20 is deformed and protrudes toward the solidified shell 10 in the mold by being pressurized in the pressurizing chamber 21, and comes into contact with the lower outer peripheral surface of the solidified shell 10 in the mold. 9 is cut off from the atmosphere (see FIG. 6 described later).

A vacuum pump 26 is provided in the gas suction hole 25.
Is connected to the outside of the water-cooled mold 1, and by driving the vacuum pump 26, the air in the air gap portion 9 passes through the gas suction hole 25 and the gas suction pipe 29. It is constructed so that it can be sucked.

The situation when the present invention is carried out using the casting apparatus configured as described above will be described in more detail with reference to FIG. 6 at the same time. First, when casting is started, the inside of the pressurizing chamber 21 is pressurized by the pressurizing fluid A, the sealing member 20 is projected toward the solidified shell 10 in the mold, and is brought into contact with the lower outer peripheral surface of the solidified shell 10 in the mold (seal). By doing so, the air gap portion 9 is shielded from the atmosphere and brought into the state shown in FIG. In this state, by driving the vacuum pump 26, the air in the air gap portion 9 is sucked through the gas suction hole 25 and the gas suction pipe 29. When the air in the air gap portion 9 is exhausted, the lower side of the air gap portion 9 is sealed by the sealing member 20, so that the air B above the molten metal 6 is mixed with the inner wall surface of the water-cooled mold 1 and the mold. The small gap between the outer peripheral surfaces of the inner solidified shell 10 penetrates into the air gap portion 9 as indicated by the arrow D,
After that, it flows downward along the surface of the solidified shell 10 in the mold as indicated by arrow E. At this time, the air B flowing downward in the air gap portion 9 removes heat from the surface of the solidified shell 10 in the mold, exerts an action of cooling the solidified shell 10 in the mold, and promotes its solidification. As a result, reheating and remelting of the solidified shell 10 in the mold as described above are prevented,
It is possible to prevent or reduce the generation of a sweating layer or a reverse segregation layer due to the exudation of the alloying elements on the surface of the solidified shell 10 in the mold.

FIG. 7 is an enlarged explanatory view of an essential part showing another embodiment of the casting apparatus of the present invention. The basic structure is similar to that of FIG. 5, and the same reference numerals are given to corresponding parts. To avoid duplicate explanation. In this casting apparatus, a gas introduction hole 31 is formed instead of forming the gas suction hole 25 shown in FIG. 5, and the gas introduction pipe 3 is associated therewith.
2, a lubricant storage tank 33, a lubricant flow control valve 34, etc. are provided. The gas G such as an inert gas is introduced into the gas introduction hole 31 from the outside through the gas introduction hole 31, so that the gas G is injected or flows into the air gap portion 9. .

The situation in which the present invention is carried out using the casting equipment constructed as described above will be described in more detail with reference to FIG. 8 at the same time. First, at the time when casting is started, the inside of the pressurizing chamber 21 is pressurized by the pressurizing fluid A, the elastic member 20 is projected to the solidified shell 10 side in the mold, and the lower outer peripheral surface of the solidified shell 10 in the mold is sealed. It is the same as the case of FIG. 6 that the air gap portion 9 is cut off from the atmosphere to be in the state shown in FIG. In this state, the gas G such as an inert gas is externally introduced into the gas introduction hole 31 via the gas introduction pipe 32, so that the gas G is injected or flows into the air gap portion 9. When the gas G is injected or flown into the air gap part 9, the lower part of the air gap part 9 is sealed by the sealing member 20, so that the gas G flows along the outer peripheral surface of the solidified shell 10 in the mold with an arrow F. As described above, the molten metal then flows upward from the slight gap between the inner wall surface of the water-cooled mold 1 and the outer peripheral surface of the solidified shell 10 in the mold. At this time, the gas G flowing upward in the air gap portion 9 removes heat from the surface of the solidified shell 10 in the mold, and thus the solidified shell 10 in the mold.
It exerts the action of cooling and accelerates its solidification. With such a configuration, as in the configurations shown in FIGS. 5 and 6, reheat and remelting of the solidified shell 10 in the mold are prevented, and perspiration is caused by the leaching of the alloying elements onto the surface of the solidified shell 10 in the mold. It is possible to prevent or reduce the generation of the layer and the reverse segregation layer. In this casting apparatus, the lubricant storage tank 33 and the lubricant flow control valve 34 are used for the solidified shell 10 in the mold.
In order to prevent seizure of the water-cooled mold 1 or the ingot 7 and the elastic member 20 and to reduce frictional resistance, the lubricant is allowed to flow into the air gap portion 9 together with the gas G, if necessary. The structure is more effective in improving the quality of the ingot 7. The lubricant used in such a structure may be the one conventionally used in the DC casting method. For example, castor oil, rapeseed oil, silicone oil, or a mixture thereof may be used.

The shapes of the gas suction hole 25 shown in FIGS. 5 and 6 and the gas introduction hole 31 shown in FIGS. 7 and 8 are not particularly limited, and for example, a circular shape or a slit shape can be adopted. Also, the number thereof is not particularly limited, and for example, it may be formed at four locations or more in the circumferential direction of the water-cooled mold 1. In short, any structure may be used as long as it can suck air B or introduce gas G uniformly over the entire surface of the solidified shell 10 in the mold. Regarding the relationship between the gas suction holes 25 and the gas suction pipes 29, or between the gas introduction holes 31 and the gas introduction pipes 32, it is not necessary to connect them individually, but one or several gas suction pipes 29 or gas introduction pipes 32 may be used. Alternatively, a plurality of gas suction holes 25 or gas suction pipes 29 may be connected to these.

The material of the sealing member 20 is not particularly limited as long as it has elasticity and deformability enough to deform and project to the solidified shell 10 side in the mold, and has heat resistance. However, for example, heat resistant rubber, a metal foil, a metal plate, or a heat resistant rubber in which a metal foil or a metal plate is attached to the surface in contact with the solidified shell 10 in the mold can be used. Further, although the seal member 20 is deformed by the action of the pressure from the pressurizing chamber 21 in the above-described configuration,
The means for deforming the seal member 20 is not limited to such a configuration, and may be achieved by a mechanical action such as a cylinder.

When the pressurizing chamber 21 is provided, the pressurizing chamber 2
The pressurizing fluid A introduced into 1 may be any medium capable of transmitting pressure, and gas such as air or argon or liquid such as water or oil can be used, but responsiveness and cost are taken into consideration. Water, which is an incompressible fluid, is then preferred. The shape of the water-cooled mold 1 is not particularly limited, and a generally-used shape such as a circular or rectangular plane shape of the pouring port may be used.

Although the structure shown in FIGS. 5 and 6 does not show the structure for supplying the lubricant, in such structure as well, for example, the lubricant is applied to the upper inner wall surface of the water-cooled mold 1. It goes without saying that the lubricant may be supplied by the above means. 5 and 6, the gas suction holes 25 and the gas introduction holes 31 are individually provided in FIGS. 7 and 8, respectively. The suction hole 25 and the gas introduction hole 31 may be provided side by side, and these may be arranged alternately or arbitrarily in the circumferential direction. However, it is needless to say that even when the casting apparatus is constructed in this way, it is necessary to operate separately when sucking the atmosphere and when introducing the gas. Next, examples will be shown.

[0027]

【Example】

Example 1 The present invention was carried out using the casting apparatus shown in FIGS. 5 and 6 under the following conditions to cast an Al—Mg-based 5083 alloy.
Further, the conventional method was also carried out by using the casting equipment shown in FIGS. 1 and 2 described above, in which the gas suction hole 25 and the seal member 20 were not provided (other conditions are the same). (Casting conditions) Mold cross-sectional dimension: 500 × 1500 (mm) Casting speed: 45 mm / min Cooling water amount: 75 m ³ / hr Gas suction holes: Pore diameter 1.0 mm, pitch 4 mm, entire circumference of the mold inner surface Pressurizing fluid: Water Sealing member : Heat resistant rubber

The state of perspiration on the surface of the solidified shell in the mold was visually observed, and the thickness and surface roughness of the reverse segregation layer in the surface layer of the obtained ingot were measured. At this time, the thickness of the reverse segregation layer was measured by line analysis with an X-ray microanalyzer from the center of the ingot width direction (1500 mm direction) toward the inside from the ingot surface, the concentration distribution of alloying components such as Mg. did. Further, the ingot ingot surface roughness was evaluated by the maximum value obtained by measuring unevenness with a surface roughness meter. The results are shown in Table 1 together with the suction air flow rate, the pressure in the pressurizing chamber, the lubricant flow rate and the like.

[0029]

[Table 1]

As is apparent from Table 1, the conventional method (N
o. In No. 1), a reverse segregation layer of about 8 mm is recognized, whereas No. 1). According to the methods of the present invention 2 to 4, it can be seen that the thickness of the reverse segregation layer is reduced or is hardly recognized. It can also be seen that the surface roughness of the ingot is also improved according to the improvement effect of the present invention.

Among the examples of the present invention, No. In the case of No. 2, the cooling effect was insufficient because the suction air flow rate was small and the generation of the reverse segregation layer could not be completely prevented, but it was reduced to about half that of the conventional method. Further, the pressure of the pressurizing chamber 21 is low. In the case of No. 3, the effect of the present invention cannot be said to be fully exhibited in spite of the large intake air flow rate, and the reverse segregation layer remains. This is because the pressure in the pressurizing chamber 21 was insufficient, so that the sealing effect of the sealing member 20 on the air gap portion 9 was insufficient, and air was sucked not only from the upper portion of the mold but also from the lower portion of the mold, and the solidified shell 10 in the mold was inflated. It is probable that sufficient cooling was not achieved. On the other hand, the air gap portion 9 is sufficiently shielded and the suction air flow rate is appropriate. In No. 4, the reverse segregation layer was scarcely recognized, and perspiration on the surface of the solidified shell in the mold was locally observed, which was so slight.
It can be seen that an ingot with a beautiful surface skin is produced.

Example 2 The present invention was carried out under the following conditions by using the casting apparatus shown in FIGS. 7 and 8 to cast an Al—Mg type 5083 alloy.
Further, the conventional method was also carried out by using the casting equipment shown in FIGS. 1 and 2 described above, in which the gas introduction hole 31 and the seal member 20 were not provided (other conditions are the same). (Casting conditions) Mold cross-sectional dimension: 500 × 1500 (mm) Casting speed: 45 mm / min Cooling water amount: 75 m ³ / hr Gas introduction hole: Pore diameter 1.0 mm, Pitch 5 mm, entire inner surface of mold Pressurizing fluid: Water Seal member : Heat resistant rubber

In the same manner as in Example 1, the state of perspiration on the surface of the ingot was visually observed, and the thickness and surface roughness of the reverse segregation layer in the surface layer of the obtained ingot were measured. The results are shown in Table 2 together with the type and flow rate of the introduced gas, the pressure in the pressurizing chamber, the flow rate of the lubricant, and the like.

[0034]

[Table 2]

As is apparent from Table 2, the conventional method (N
o. In No. 5), a reverse segregation layer of about 8 mm is recognized, whereas in No. According to the method of the present invention of 6 to 11, it can be seen that the thickness of the reverse segregation layer is reduced or hardly recognized. It can also be seen that the surface roughness of the ingot is also improved according to the improvement effect of the present invention.

Among the examples of the present invention, No. In the case of No. 6, since the amount of introduced gas was slightly small, the cooling effect was insufficient and the generation of the reverse segregation layer could not be completely prevented.
It is reduced to about half of the conventional method. Further, the pressure of the pressurizing chamber 21 is low. With No. 7, the effect of the present invention cannot be said to be fully exhibited despite the large flow rate of the introduced gas, and the reverse segregation layer remains. This is the pressurizing chamber 21
It is considered that, because the pressure of 1 was insufficient, the shielding effect of the air gap portion 9 by the seal member 20 became insufficient, the introduced gas leaked out from the lower portion of the mold, and the solidified shell 10 in the mold was not sufficiently cooled. . On the other hand, the air gap 9 is sufficiently shielded, and the introduction gas and flow rate are appropriate. In the case of Nos. 8 to 11, almost no reverse segregation layer was observed, and perspiration on the surface of the solidified shell in the mold was locally observed, so that an ingot with a clean surface skin was produced. You can see that In addition, No. 8 to 1
As is clear from the result of 1, the same effect is obtained even if the kind of introduced gas is changed.

[0037]

As described above, according to the method of the present invention, the surface of the solidified shell in the air gap portion is effectively cooled, so that reheating or remelting of the solidified shell in the mold can be prevented. As a result, it became possible to perform casting while preventing or reducing the occurrence of a reverse segregation layer which is a surface defect of the ingot. Moreover, according to the present invention, it is possible to achieve it with an inexpensive and simple structure without requiring expensive and large-scale equipment such as a high frequency coil and a power source.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a conventional DC casting method.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a schematic diagram for explaining a conventional electromagnetic casting method.

FIG. 4 is a schematic diagram for explaining a conventional hot top method.

FIG. 5 is an enlarged explanatory view of an essential part showing an embodiment of the casting apparatus of the present invention.

FIG. 6 is a perspective view of the casting device shown in FIG.
It is explanatory drawing which shows the state which interrupted | blocked the air gap part 9 by 0.

FIG. 7 is an enlarged explanatory view of a main part showing another embodiment of the casting apparatus of the present invention.

FIG. 8 is a view showing the sealing member 2 in the casting equipment shown in FIG.
It is explanatory drawing which shows the state which interrupted | blocked the air gap part 9 by 0.

[Explanation of symbols]

 1 Water-cooled mold 6 Molten metal 7 Ingot 9 Air gap part 10 Solidified shell in mold 11 Massey zone 20 Sealing member 21 Pressurizing chamber 22 Cooling water jet nozzle 25 Gas suction hole 26 Vacuum pump 27 Flow control valve 28 Flow meter 29 Gas suction Pipe 31 Gas introduction hole 32 Gas introduction pipe 33 Lubricant storage tank 34 Lubricant flow control valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruhiko Toda 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Works, Ltd. Kobe Research Institute

Claims (2)

[Claims] 1. A molten metal is poured into a water-cooled mold to solidify the molten metal to form a solidified shell in the mold, and the upper outer peripheral surface of the ingot is cooled by cooling water jetted from below the mold. In a metal casting apparatus configured to pull the ingot downward while being, in contact with the lower outer peripheral surface of the solidified shell in the mold, below the water-cooled mold and above the cooling water jetting part. By providing a seal member capable of contacting the seal member with the lower outer peripheral surface of the solidified shell in the mold, an air gap portion formed between the inner wall surface of the water-cooled mold and the outer peripheral surface of the solidified shell in the mold is formed. It is configured so as to be shielded from the atmosphere, and (a) is provided with a gas suction hole opened in the blocked air gap portion, or (b) is provided with a gas introduction hole opened in the blocked air gap portion. And a metal casting device. 2. The casting apparatus according to claim 1, wherein the sealing member is brought into contact with the lower outer peripheral surface of the solidified shell in the mold, whereby the inner wall surface of the water-cooled mold and the outer peripheral surface of the solidified shell in the mold. The air gap part formed between the air gap part is shielded from the atmosphere, and (a) the air in the air gap part is sucked from the gas suction hole, so that the contact between the water-cooled mold and the solidified shell in the mold is slightly reduced. Air is sucked into the air gap portion from a small gap, or (b) a small gap in the upper contact portion between the water-cooled mold and the solidified shell in the mold while introducing gas from the gas introduction hole into the air gap part. The introduced gas is discharged from the chamber, and the outer peripheral surface of the solidified shell in the mold, which faces the air gap portion, is operated while being cooled by suctioned air or introduced gas. Metal casting method.