JPH05309472A - Casting device and casting method - Google Patents

Abstract

PURPOSE: To execute, by one process, the process for melting metal and the process for separating the of a mold from the inside of a pressure container by fluid (molten metal). CONSTITUTION: A chamber 16 for melting a raw material 18 is arranged in a pressure container 12. The chamber is communicated with a mold 20 so that a molten metal can pass through a passage 24, and a filter 26 is arranged in the passage. The raw material molten in the chamber is prevented from being moved to the mold by the existence of the filter before the container is pressurized. When the container is pressurized, the molten material passes through the filter and is forcedly fed into the mold. Grain-oriented solidification is executed in the material within the mold.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to casting. More specifically, the present invention relates to a pressure casting apparatus and method for forcing raw materials into the mold from the top of the apparatus.

[0002]

BACKGROUND OF THE INVENTION A composite product having a phase in which a metal matrix is reinforced by ceramic particles or the like has both rigidity and wear resistance of the reinforced phase and ductility and toughness of the metal matrix, and can be applied to various applications. it can.

For example, aluminum-based composites are manufactured by various metallurgical methods. As these methods, powder metallurgy technology, liquid metal infiltration technology and the like are known. In these methods, pressure casting, vacuum casting, stirring agents and wetting agents are used. JP-A-2-2847
56 describes a pressure casting apparatus including a mold, metal and heating means in a pressure vessel. In addition, the casting method described in the publication has a step of degassing the inside of the pressure vessel while melting the metal in the crucible. The mold has a snorkel and is placed on top of the crucible. The molten metal communicates with the mold by inserting a snorkel into the crucible containing the molten metal to separate the interior of the mold from the interior of the pressure vessel. Next, the molten metal is forced into the mold by using an inert gas. In this method, a step for melting the metal and a step for separating the inside of the mold and the inside of the pressure vessel by the fluid are separately required. Further, a mechanical device such as a crucible lifter is required to connect the snorkel and the molten metal before pressurizing.

The present invention is an improvement on the above method and apparatus in which the solid metal is placed in a chamber above the mold. A fluid (molten metal) communicates with this chamber and the inside of the mold. When the metal melts, the passage can be covered with molten metal, so in one step, the inside of the mold and the inside of the container are isolated or separated (isolat
e) You can.

[0005]

SUMMARY OF THE INVENTION The casting apparatus of the present invention comprises a pressure vessel and a pressurizing means for pressurizing the vessel. Fluid is allowed to communicate between the pressurizing device and the container. A chamber for melting raw materials is provided in the pressure vessel. The mold can be provided with a preform and is placed in a container. The mold is in communication with the chamber via a passage, and when the container is pressurized by the pressurizing means, the molten material in the chamber is forced into the lower mold. A heating device is provided in the container. Means are provided for directionally solidifying the material fed into the mold.

The casting method of the present invention comprises the steps of placing a raw material in a chamber and loading a pressure vessel, the raw material passing through a mold and a passage which can include a preforming part. Communicate. A filter is installed in the passage. Next, there is a step of melting the raw material in the chamber, and the melted raw material seals the passage. As a result, the inside of the mold and the inside of the container are shut off from each other. The filter prevents the molten material from entering the mold. Next, the step of pressurizing the container is performed, and the molten material is forcedly fed into the inside of the mold and the preforming portion through the filter.
Next, there is a step of directionally solidifying the material in the mold.

Another embodiment of the casting apparatus of the present invention comprises a pressure vessel comprising a melting section and a surface separated mold section. The lysis section is located at the top of the pressure vessel. The melting section includes a crucible for containing and melting raw materials, and a first crucible formed on a bottom surface of the crucible.
And a second hole below the first hole and formed on the surface. Furthermore, a plug lift device including a plug and a plug lifter is provided, and the plug lifter raises and lowers the plug to open and close the first hole. When the plug descends, the first hole is closed and molten material cannot flow out of the crucible.
The mold section is located at the bottom of the pressure vessel.
The mold section comprises a chamber for containing the molten material. The mold section also comprises means for pressurizing the container. The pressurizing means and the container are in fluid communication. The mold has a passage through which the fluid flows from the chamber to the inside of the mold. A filter is provided in the passage to prevent molten material from entering the interior of the mold prior to pressing.
Furthermore, a means is provided for heating the raw material in the crucible, the raw material is melted in the crucible, and when the plug is lifted from the hole of the crucible by the plug lifter, the raw material is melted into the chamber of the mold section. It is designed to be able to flow downward. Means for directionally solidifying the molten material are also provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, the same reference numerals are attached to the same or similar elements. FIG. 1 shows a sectional view of the casting apparatus (10). The casting apparatus (10) is a pressure vessel (12) and pressurizes the vessel, preferably degassing (e
and means for vacuating). The container (12) is preferably made of steel. The degassing / pressurizing means and the container (12) are in fluid communication with each other through the port (14). The pressure vessel (12) of the casting apparatus (10) is provided with a chamber (16) for melting a raw material (18) such as aluminum. Also, the mold (20) is placed in the pressure vessel (12). The mold (20) is preferably provided with a preform, that is, a preforming portion (22). The present invention is not limited to the mold provided with the preforming portion. Fluid flows from the chamber (16) into the mold (20) via the passage (24).
Incidentally, in order to prevent the molten material (18) from entering the inside of the mold (20) when the container (12) is not pressurized yet, a porous ceramic filter (in the passage (24) ( It is desirable to insert 26). Mold (20) is 304
It is preferably made from stainless steel, but of course other materials can be used. Preforming part (22)
Is preferably made from silicon carbide fibers.

The mold (20) is in fluid connection (f) with the molten material (18).
When the container (12) is pressurized by the pressurizing means, the molten material (1) in the chamber (16)
8) is forced down the mold (20). The pressure of the preformed part of the silicon carbide fiber and the molten aluminum in the mold (20) is usually 1000 to 2000 PS.
I, and 1300 to 1500 PSI is desirable. It should be noted that the required pressure is related to the fiber amount. Generally, the higher the amount of fiber per unit volume, the greater the pressure required to drive the molten material between the fibers.

The casting apparatus comprises a chamber (16) and a mold (2
Means for heating the raw material (18) in 0) are provided.
By this heating means, the raw material (18) is melted in the chamber (16) and when the liquid seal is formed on the passage (24), the container (12) is pressed by the pressing means and the mold is molded. The molten state is maintained even when fed into (20). The heating means is preferably located in the container (12). The heating means must be able to supply sufficient heat to keep the raw materials in a molten state. For example, in the case of aluminum, the temperature is 600 degrees or higher, preferably 650-
Must be maintained in the 700 ° C range. The heating means is
Furnace for heating mold (20) and raw material (18)
(28), the furnace may be placed around the mold (20) to allow for uniform heating of the mold (20), preform (22) and raw material (18). desirable. The casting apparatus further comprises a solidification means for directional solidification of the raw materials in the mold.

The preferred solidification means is a chill plate.
e) (30). The cooling plate (30) is connected to a lifter (32) for lifting the cooling plate and can be placed in a position capable of thermal contact with the bottom of the mold (20) as shown in FIG. I have to. FIG. 6 shows a casting device
(10) shows a schematic cross-sectional view of the cooling plate (30) with the lifter (3
When lifted by 2), the mold (20) will
Thermal contact with 0). It should be noted that FIGS. 1 to 6 are not drawn to scale and that the various elements and structural relationships are shown regardless of their actual size.

Alternatively, the means for directional solidification may be provided with means for moving the mold (20) with the molten material (18) into a cold chamber (21) within the container (12). Means for moving the mold (20) to the cold chamber (21) may be, for example, a rod or cable (23) mounted on top of the chamber (16), one of the pistons (25) located below the mold (20) or Both are included. As shown in FIGS. 12 and 13, the low temperature chamber (21) is provided with a pipe (27) around the lower part of the container (12), and water is made to flow in the pipe to cool it.

The solidifying means may be provided with an inlet port (29) penetrating the container (12) and on the axis of the mold (20).
By sending cold gas into the container (12) through the inlet, the gas collides with the mold (20) and the raw material in the mold (20) solidifies with a certain direction (FIG. 14).
reference).

As shown in FIG. 15, the solidifying means is a container (12).
The temperature of the gas inside may be graded. To form the temperature gradient, for example, the vessel (12) containing the molten material (18) in the chamber (16) is first degassed. The pressure inside the container (12) increases due to the introduction of gas. The force of the gas forces the molten material (18) through the filter (26) and into the mold (20). The molten material (18) is molded around a preform (22) disposed in a mold (20). The gas enters the container (12), pressurizes the container and is heated by the molten material (18).
The temperature of the gas subsequently introduced into the container (12) is lower than the gas already heated by the molten material (18). As more gas enters the container (12), the pressure will increase, so
The molten material (18) is forced to feed and infiltrate into the preform (22). The gas already heated in the vessel (12) continues to increase in pressure as the cold gas is introduced into the vessel (12). 1000PSI in the container (12)
The introduction of this pressure creates a temperature gradient of about 600 degrees between the top and the bottom of the container (12) having a length of about 12 inches. Since the low temperature gas collects at the bottom of the container (12), the solidification of the raw material (18) proceeds in a directional manner.

As another embodiment of the solidifying means, a mold (2
(0) and a predetermined distance from each other in the container (12)
body) (23) can also be deployed. As the pressure inside the container (12) increases, the heat transfer between the cooling body (33) and the mold (20) increases, and the solidification of the raw material (18) proceeds in a directional manner. The pressure-applying gas acts as a heat conductor between the cooling body (33), which can be cooled with, for example, water, or may be at the bottom of the container (12). Cooling body
The part of the mold (20) closest to the (33) solidifies with directionality according to a certain law. As the pressure increases and the gas in the container becomes thicker, the heat transfer characteristic of the gas increases, and the cooling effect of the mold (20) increases.

As another example, referring to FIG. 7, the container (12) includes a mold section (34) and a melting section (36).
Is equipped with. A mold (20) having a preforming part (22) therein is attached to a chamber (1) of a mold section (34).
It is located below 6). The mold section is at the bottom of the container and is provided with heating means, preferably a mold furnace (38). The mold furnace (38) allows the molten state to be maintained even when the raw materials enter the mold (20) and the preforming section (22). However,
When performing the work of the casting equipment (10), the mold furnace
It should be understood that (38) is not necessary.

The melting section comprises a crucible (40),
The raw material (18) is stored in the crucible and melted. A through hole (42) is formed on the bottom surface of the crucible (40). Lifting the plug (44) of the plug lifter (46) allows the hole (4
2) is opened and closed. The lifting of the plug (44) is performed by the plug lifter (48) of the plug lift device (46). The plug (44) is preferably made of ceramic. The melting section is provided with a heating means, which melts the raw material (18) in the crucible (40) and maintains the molten state. Therefore, the plug lifter (48) rises and the hole
When the (42) opens, the molten material flows through the holes (42). For example, for aluminum, the temperature should be maintained above 600 ° C, preferably in the range 650-700 ° C. It is desirable that the heating means be provided with a melting furnace (50) around the crucible (40) so that substantially uniform heat can be supplied to the raw materials. The mold section (34) and the melting section are
Separated by an insulating barrier (52), the crucible (40)
A hole (54) is formed below the hole (42). As a result, as shown in FIG. 9, when the plug (46) is lifted up by the plug lifter (48) and separated from the hole (42), the molten raw material in the crucible (40) has the hole (42) and the heat insulating hole (54). You can pass through. Insulation (52) maintains a temperature differential between the melting section and the mold section. Since the means for directional solidification is also provided, the solidification of the molten raw material proceeds directionally as described above.

The present invention also provides a method of making a fiber reinforced material. The manufacturing method of the present invention comprises a mold (20) having a preforming part (22) and a passage (24),
It has a step of loading in (12). filter
Deploy (26) in passage (24). Next, the step of placing the raw material (18) in the chamber (16) of the pressure vessel (12) is performed as shown in FIG.
It is performed as shown in. Next, attach the pressure vessel (12) to the port (1
The step of degassing from 4) is performed as shown in FIG. Next, the step of melting the raw material (18) in the chamber (16) is performed as shown in FIG.
It is performed as shown in. In the step of pressurizing the container (12),
As shown in FIG. 4, the molten material (18) is forced into the mold (20) and further into the preforming section (22). The pressurizing step preferably includes a step of controlling the pressurizing rate of the container (12), and may have time for the pressure in the mold (20) to momentarily reach equilibrium with the pressure in the container (12). It can be so. Next, as shown in FIG. 6, the step of directionally solidifying the raw material is performed by, for example, a cooling plate lifter (3
This can be done by lifting 2) and bringing the cooling plate (30) into thermal contact with the bottom of the mold (20). The pressure is then released and the mold (20) is removed from the pressure vessel (12).

The present invention relates to a section, a melting section
(36) and mold section (34) separated pressure vessel (1
It relates to a method of making a fiber reinforcement by using 2). The method loads a pressure vessel (12) by placing a mold (20) including a preform (22) and a filter (26) into a mold section (34) of the pressure vessel (12). Have a process. Also, the crucible (4 containing the raw materials (18)
0) is placed in the dissolution section of the pressure vessel (12). As shown in FIG. 7, the plug lift device (46)
The plug (44) seals the hole (42) of the crucible (40). Next, the step of degassing the pressure vessel (12) from the port (14) is performed as shown in FIG. In the process of lifting the plug (44) using the plug lifter (48), the molten material
(18) is the chamber through the hole (42) and the hole (54) in the insulation barrier
It flows into (16). In the step of pressurizing the container (12), as shown in FIG.
As shown at 0, the molten material (18) moves downward in the mold (20) and is forced into the preforming section (22). The pressurizing step preferably includes a step of controlling the pressurizing rate of the container (12), and has a time for the pressure in the mold (20) to momentarily reach equilibrium with the pressure in the container (12). To be able to Next, the step of directionally solidifying the raw material is performed, for example, by lifting the cooling plate lifter (32) to bring the cooling plate (30) into thermal contact with the bottom of the mold (20) as shown in FIG. You can
The pressure is then released and the mold (20) is removed from the pressure vessel (12).

In the preferred embodiment described above, the chamber (16) is filled with aluminum and, after being placed in the container (12), the container is sealed. In addition, it is desirable to seal the container using a high temperature seal VITON (registered trademark). The container (12) has a port (14) as shown in FIG.
Degas through to remove any gas from the container (12). The mold furnace (28) is activated to melt the aluminum in the chamber (16) as shown in FIG. During this time, the container is continuously degassed. Since the container (12) and the mold (20) are degassed, voids are rarely formed in the fiber reinforced material after the molten material has penetrated the preform (22).

When the aluminum in the chamber (14) melts, the molten aluminum covers the passage (24),
There is no direct communication between the inside of (20) and the inside of the container.
There is no flow of hot water into the interior. As shown in FIG. 4, when the pressing means is actuated, the molten aluminum in the crucible (14) is forcibly sent into the mold (20) and the preforming section (22) through the passage (24).

Once the aluminum is melted, the pressurized nitrogen gas is supplied to the container (1
2) is sent in. The pressure in the vessel (12) is high throughout the vessel, but the surface of the molten aluminum in the chamber (16) is especially high. The molten aluminum in the chamber (16) prevents the pressurized gas in the container (12) from passing through the passage (24) and into the mold (20). Since fluid does not directly communicate with the inside of the mold (20) and the pressure vessel, a pressure difference occurs between the inside of the pressure vessel (12) and the inside of the mold chamber (18). When this pressure difference occurs, the molten aluminum is forced downwardly through the passage 24 and the porous ceramic filter 26, and is sent into the mold chamber 18 as shown in FIG. The amount of molten aluminum fed into the mold (20), and thus into the preform (22), corresponds to the container pressure value at the surface of the molten aluminum in the crucible (14). The higher the pressure of the container, the more the inside of the mold (20) and the container (1
Since the force for compensating the pressure difference between the inside of 2) and the inside of
It is sent to 2). When aluminum is forced into the preforming part (22), the pressure between the inside of the mold (20) and the inside of the container (12) becomes equilibrium. The pressure difference between the inside and the outside of the mold (20) can be controlled by controlling the pressing speed. The slower the pressing speed, the smaller the pressure acting on the outside of the mold (20).
Therefore, it is necessary to reduce the wall thickness of the mold and reduce its strength.

When the molten aluminum fills the preform (22), the lifter (32) lifts the cooling plate (30) and makes thermal contact with the bottom of the mold (20). An example of the lifter (32) is an air piston that is sealed by an O-ring and can be retracted into and out of the container. In this way, the molten aluminum in the mold (20) closest to the water cooling plate (30) solidifies. The solidification of the molten aluminum propagates like waves from the bottom of the mold (20). Since the aluminum in the mold (20) contracts when cooled, the pressurizing means is operated to allow the excess molten metal to be supplied into the mold (20) even while solidification proceeds in a directional manner.

Although the present invention has been described in detail based on the preferred embodiments, such embodiments are merely illustrative, and those skilled in the art can understand from the spirit and scope of the invention defined in the claims. It should be understood that modifications can be made without departing.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one step of a top casting method of the present invention.

FIG. 2 is a schematic cross-sectional view showing one step of the top casting method of the present invention.

FIG. 3 is a schematic cross-sectional view showing one step of the top casting method of the present invention.

FIG. 4 is a schematic cross-sectional view showing one step of the top casting method of the present invention.

FIG. 5 is a schematic cross-sectional view showing one step of the top casting method of the present invention.

FIG. 6 is a schematic cross-sectional view showing a step of the top casting method of the present invention.

FIG. 7 is a schematic cross-sectional view showing a casting apparatus and method for top casting in which a substantial temperature difference is provided between a mold and a raw material.

FIG. 8 is a schematic cross-sectional view showing the casting apparatus and method for top casting in which a substantial temperature difference is provided between the mold and the raw material.

FIG. 9 is a schematic cross-sectional view showing the casting apparatus and method for top casting in which a substantial temperature difference is provided between the mold and the raw material.

FIG. 10 is a schematic cross-sectional view showing a casting apparatus and method for top casting in which a substantial temperature difference is provided between a mold and a raw material.

FIG. 11 is a schematic cross-sectional view showing a casting apparatus and method for top casting in which a substantial temperature difference is provided between a mold and a raw material.

FIG. 12 is a schematic cross-sectional view showing a state where the mold moves into the low temperature chamber of the pressure vessel.

FIG. 13 is a schematic cross-sectional view showing a state where the mold moves into the low temperature chamber of the pressure vessel.

FIG. 14 is a schematic cross-sectional view of a gas cooling means.

FIG. 15 is a schematic cross-sectional view illustrating a gas temperature gradient.

FIG. 16 is a schematic sectional view illustrating a cooling transmission mechanism.

[Explanation of symbols]

 (10) Casting equipment (12) Pressure vessel (16) Chamber (18) Raw material (20) Mold (22) Preforming part (24) Passage (26) Filter (30) Cooling plate (32) Lifter (38) Mold furnace (40) Crucible

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[Procedure amendment]

[Submission date] July 10, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] Figure 12

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[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

[Correction method] Change

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[Fig. 13]

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[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

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[Document name to be corrected] Drawing

[Correction target item name] Fig. 15

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[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 16

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FIG. 16

Claims (11)

[Claims] 1. A means for pressurizing a pressure vessel, comprising: a pressure vessel, wherein the pressure means is in fluid communication with the pressure vessel; a chamber disposed in the pressure vessel, the chamber comprising: To be able to melt the raw materials in;
A mold disposed in a pressure vessel and fluidly connected to a chamber via a passageway, the mold being capable of including a preform, when the vessel is pressurized by a pressure means. , The molten material in the chamber is forced into the mold through a passage, which contains a filter, which prevents the molten material from entering the inside of the mold before pressurization. The molten material passes through the filter when the pressure is applied; a means for heating the material in the chamber and the mold, which melts the material in the chamber and pressurizes the container. When heated by the means, the molten material is maintained so that the molten material is forced into the mold, the heating means It is deployed within a vessel; solidifying means the material in the mold is directionally solidified; in which casting apparatus comprising a. 2. The heating means includes a furnace for heating the material in the mold and chamber.
The device according to. 3. The apparatus of claim 1 wherein the solidifying means includes a cooling plate and a lifter for raising and lowering the cooling plate, the cooling plate being in thermal contact with the bottom of the mold. 4. An apparatus according to claim 1, wherein the pressure vessel comprises a cryogenic chamber and the solidifying means comprises means for moving the mold into the cryogenic chamber. 5. An inlet for introducing the cooling gas into the container is arranged on the axis of the mold by penetrating the container,
Cooling gas is introduced from the inlet to collide with the mold,
The apparatus of claim 1, wherein the material in the mold is directionally solidified. 6. The solidifying means includes a cooling body arranged in the container, the cooling body is arranged at a predetermined distance from the mold, and when the pressure inside the container increases, the cooling body The apparatus of claim 1 wherein the amount of heat transfer to and from the mold is increased to allow directional solidification of the material. 7. The apparatus according to claim 1, wherein the solidifying means is a temperature gradient of hot gas. 8. A step of disposing raw materials in a chamber and loading a pressure vessel, wherein the chamber and the mold are in fluid communication with each other through a passage, and the mold includes a preforming part. And the passage is equipped with a filter; the step of dissolving the raw materials in the chamber, the dissolved material seals the passage and separates the inside of the mold from the inside of the container, Prevents molten material from entering the mold; the process of pressurizing the container so that the molten material is forced to pass through the filter and into the mold and preform. And a step of solidifying the material in the mold in a directional manner. 9. A pressure vessel in which the melting section and the mold section are separated by a surface, the melting section being provided on the top of the pressure vessel, for crucible for containing and melting the material, and for the bottom of the crucible. The plug lift device has a first hole formed in the surface and a second hole formed in the surface below the first hole and separating the melting section and the mold section. A plug lifter is provided which raises and lowers the plug to open and close the first hole and prevents molten material from flowing out of the crucible when the plug is lowered and positioned in the first hole. And the mold section is located below the pressure vessel and includes a chamber for containing the dissolved material; a means for pressurizing the vessel and in fluid communication with the vessel. A mold having a passageway for fluid flow between the chamber and the interior of the mold, the passageway including a filter to prevent molten material from entering the interior of the mold prior to pressurization. Cage; means for heating the material in the crucible, wherein the heating means melts the material in the crucible, and when the plug is lifted by the plug lifter and the plug is separated from the hole in the crucible, the molten material is melted into the mold section. The casting device is provided with a solidification means for maintaining the molten state of the material so as to flow downward into the chamber of, and solidifying the molten material in a directional manner. 10. The apparatus of claim 8 including means for heating the mold within the mold section such that molten material does not solidify as it enters the mold. 11. The apparatus of claim 1 including means for degassing the vessel, the degassing means being in fluid communication with the pressure vessel.