CN116000266A - A kind of aluminum silicon carbide differential pressure casting directional solidification equipment - Google Patents

Abstract

An aluminum silicon carbide differential pressure casting directional solidification device relates to the technical field of casting, and comprises a reaction kettle upper cover for preserving heat and pressure of a die and realizing differential pressure filling and aluminum alloy liquid directional solidification; the inner part of the upper cover of the reaction kettle is provided with an inner heating wire for heating and preserving heat of the die; the inside of reation kettle upper shield is provided with the inside cooling line of reation kettle upper shield that is used for realizing the directional cooling of mould. According to the material solidification mechanism, the directional cooling control is adopted by the equipment, so that the directional solidification of the product is realized, the compactness of crystals is improved, and the generation of internal shrinkage cavities and microcracks is avoided. The directional cooling of the die from bottom to top is realized, the shrinkage cavity solidified at the bottom is fed by the aluminum alloy liquid in the die under the action of pressure, the shrinkage cavity is gradually moved upwards, and finally the shrinkage cavity is concentrated in the pouring gate reserved at the top of the die. The density of the inside of the AlSiC composite material is improved, and the generation of internal shrinkage cavities is avoided.

Description

A kind of aluminum silicon carbide differential pressure casting directional solidification equipment

technical field

The invention relates to the field of casting technology, in particular to an aluminum silicon carbide differential pressure casting directional solidification equipment.

Background technique

Al-SiC (aluminum silicon carbide) composite material, with its unique combination of high thermal conductivity, low expansion coefficient and bending strength, makes it an irreplaceable material in the field of high-power electronic packaging. In industrial manufacturing, silicon carbide particles are generally first manufactured into a silicon carbide preform in the target finished shape. This preform distributes a large number of passing pores. Then, using special equipment, the molten aluminum is hydraulically cast into the micro-voids to form an aluminum-silicon carbide composite.

The existing differential pressure casting equipment (or anti-gravity casting equipment) for AlSiC preforms does not achieve directional solidification during the solidification process of the aluminum alloy, resulting in random defects such as shrinkage cavities and microcracks in the product. According to the solidification mechanism of the material, the device of the invention adopts directional cooling control, realizes the directional solidification of the product, improves the compactness of crystallization, and avoids the generation of internal shrinkage cavities and microcracks.

Contents of the invention

In order to achieve the directional solidification of the above products, improve the compactness of crystals, and avoid the generation of internal shrinkage cavities and microcracks, the present invention provides the following technical solutions:

A directional solidification equipment for aluminum silicon carbide differential pressure casting, including a reaction kettle upper cover for heat preservation and pressure maintenance of the mold to realize differential pressure filling and directional solidification of the aluminum alloy liquid;

The inside of the upper cover of the reaction kettle is provided with a heating wire inside the upper cover of the reaction kettle for heating and insulating the mould;

The inside of the reactor upper cover is provided with a cooling pipeline inside the reactor upper cover for realizing directional cooling of the mould.

As a preference, an upper bracket is provided on the outside of the upper cover of the reactor, and the upper bracket contains a hydraulic pressure

(Mechanical) Lifting and lowering mechanism.

Preferably, a mold for forming the AlSiC composite material is placed inside the upper cover of the reaction kettle.

Preferably, the inside of the mold is provided with a SiC preform, which is formed by pressing (or firing) SiC powders of different particle sizes, and has a connected porous structure on the surface and inside. During the differential pressure casting process, the aluminum alloy The liquid fills the internal pores of the SiC preform and solidifies to form an AlSiC composite material.

Preferably, the bottom of the upper bracket is provided with a middle partition of the reaction kettle for supporting the mold and the upper bracket, and the interior of the middle partition reactor is provided with a cooling pipeline inside the middle partition of the reaction kettle.

Preferably, a riser heating body is fixedly inserted into the interior of the partition in the reaction kettle.

Preferably, a liquid riser is fixedly inserted into the interior of the liquid riser heating body.

Preferably, a cooling water channel is provided inside the partition plate in the reaction kettle, and a structure for installing a liquid riser heating body and a liquid riser is left in the middle part.

As preferably, the bottom of the partition in the reactor is provided with a lower tank of the reactor;

The upper left part of the lower tank of the reaction kettle is provided with a gas inlet of the lower tank of the reactor for connecting the gas inlet of the lower tank of the reactor to an external compressed gas tank and introducing compressed gas into the lower tank of the reaction kettle;

The lower right part of the lower tank body of the reaction kettle runs through a safety valve of the lower tank body of the reaction kettle for discharging excess gas and releasing pressure inside the tank body.

Preferably, it also includes aluminum alloy liquid;

Graphite crucibles used for melting and smelting aluminum alloys and keeping aluminum alloy liquids warm;

Heating wire used to heat the crucible inside the lower tank of the reactor;

Firewall for fixing heating wires and insulation.

Beneficial effect

Compared with prior art and product, the beneficial effect of the present invention is:

1. According to the solidification mechanism of the material, the equipment of the present invention adopts directional cooling control to realize the directional solidification of the product, improve the compactness of crystallization, and avoid the generation of internal shrinkage cavity and microcracks.

2. The heating wire inside the upper cover of the reaction kettle is used to heat and keep the mold warm, so as to ensure the constant temperature of the aluminum alloy liquid during the filling process, to compensate for the heat loss of the mold during the differential pressure casting process, and to ensure that the aluminum alloy liquid fills the mold cavity and Before the internal pores of the SiC preform, the aluminum alloy liquid is always in a liquid state.

3. The cooling pipeline inside the middle partition of the reaction kettle is used in the differential pressure casting process. After the aluminum alloy liquid filling is completed, the cooling liquid inside the middle partition begins to flow into the cooling liquid to reduce the temperature at the bottom of the mold, and cooperate with the reaction kettle The liquid flow sequence of the cooling pipeline inside the upper cover realizes the directional cooling of the mold from bottom to top. Move up, and finally focus on the gate reserved at the top of the mold. Improve the internal density of AlSiC composite materials and avoid the generation of internal shrinkage cavities.

4. The heating body of the riser pipe is used to heat and keep warm the riser pipe to ensure the flow channel inside the riser pipe is smooth. During the differential pressure casting process, the thickness of the aluminum alloy wall inside the riser pipe is constant and the flow channel is not blocked. , The aluminum alloy liquid inside the riser can smoothly flow back into the crucible without solidifying and blocking the riser, and will not affect the next differential pressure casting.

5. The tank safety valve under the reactor is used to discharge excess gas when the internal pressure of the reactor reaches a safe value, and relieve the internal pressure of the tank to ensure safety and the smooth progress of differential pressure casting.

6. The gas inlet of the lower tank of the reaction kettle is used to connect the external compressed gas tank, introduce compressed gas, apply pressure to the aluminum alloy liquid inside the inner crucible of the reaction kettle, and form a pressure difference with the upper tank of the reaction kettle, so as to realize differential pressure casting (or anti-gravity casting).

Description of drawings

Fig. 1 is the structural connection schematic diagram of the present invention;

Fig. 2 is a schematic diagram of heating molten aluminum in the present invention;

Fig. 3 is a schematic diagram of mold loading of the present invention (the mold contains prefabricated body);

Fig. 4 is a schematic diagram of mold heating of the present invention;

Fig. 5 is a schematic diagram of differential pressure filling according to the present invention;

Fig. 6 is a schematic diagram of stereotyped solidification of the present invention;

Fig. 7 is the demoulding schematic diagram of the present invention;

Fig. 8 is a schematic diagram of the mold structure of the present invention;

Fig. 9 is a schematic diagram of a SiC preform of the present invention;

Fig. 10 is the finished product of AlSiC heat dissipation substrate differential pressure casting of the present invention;

Figure 11 is a photo of the SiC preform and internal pores of the present invention;

Fig. 12 is the AlSiC metallographic structure formed by the equipment of the present invention;

Fig. 13 is a schematic diagram of the process flow of the present invention.

In the figure: 1. Upper bracket; 2. Reactor upper cover; 2-1. Internal heating wire of the reactor upper cover; 2-2. Internal cooling pipeline of the reactor upper cover; 3. Mold; 4. Prefabricated body; 5 , Partition in the reaction kettle; 5-1. Cooling pipeline inside the partition in the reaction kettle; 6. Heating body of the rising liquid pipe; 7. Liquid rising pipe; 8. Tank body under the reaction kettle; Air inlet of the tank; 8-2. Tank safety valve under the reaction kettle; 9. Fire wall; 10. Heating wire; 11. Graphite crucible; 12. Aluminum alloy liquid;

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example:

A directional solidification equipment for differential pressure casting of aluminum silicon carbide, including a reaction kettle cover 2 for heat preservation and pressure maintenance of the mold, realizing differential pressure filling and directional solidification of the aluminum alloy liquid;

The inside of the reactor upper cover 2 is provided with a heating wire 2-1 inside the reactor upper cover for heating and insulating the mold;

The inside of the reactor upper cover 2 is provided with a reactor upper cover internal cooling pipeline 2-2 for realizing directional cooling of the mould.

in:

a. An upper bracket 1 is provided outside the upper cover 2 of the reactor, and the upper bracket 1 contains a hydraulic (mechanical) lifting and lowering mechanism for fixing and moving the upper cover 2 of the reactor.

b. The heating wire 2-1 inside the upper cover of the reaction kettle is used to heat and keep the mold 3 warm, so as to ensure the constant temperature of the aluminum alloy liquid 12 during the mold filling process, to compensate for the heat loss of the mold during the differential pressure casting process, and to ensure that the aluminum alloy liquid Before the 12 fills the mold cavity and the internal pores of the SiC prefabricated body 4, the aluminum alloy liquid 12 remains in a liquid state all the time.

A mold 3 for forming AlSiC composite material is placed inside the upper cover 2 of the reaction kettle. The inside of the mold 3 is provided with a SiC preform 4. The SiC preform 4 is formed by pressing (or firing) SiC powders of different particle sizes. The surface and the interior have a connected porous structure. During the differential pressure casting process, the aluminum alloy liquid 12 Fill the internal pores of the SiC preform and solidify to form an AlSiC composite material.

in:

A. The mold 3 is used to form the AlSiC composite material, and the porous SiC preform 4 is pre-placed in the mold cavity; there is a gap between the preform 4 and the inner cavity of the mold, which is convenient for the aluminum alloy liquid 12 to fill the internal pores of the SiC preform 4 and solidify Finally, the finished product of AlSiC composite material is obtained.

The bottom of the upper bracket 1 is provided with a middle partition 5 of the reactor for supporting the mold 3 and the upper bracket 1, and the inside of the middle partition reactor 5 is provided with a cooling pipeline 5-1 inside the partition of the reactor.

in:

α. The internal cooling pipeline 5-1 of the partition in the reaction kettle is used in the differential pressure casting process. After the aluminum alloy liquid filling is completed, the internal cooling pipeline of the middle partition starts to flow into the cooling liquid to reduce the temperature at the bottom of the mold 3 , cooperate with the liquid flow sequence of the internal cooling pipeline 2-2 of the upper cover of the reaction kettle to realize the directional cooling of the mold 3 from bottom to top. Carry out shrinkage, gradually move up the shrinkage cavity, and finally concentrate in the gate reserved on the top of the mold. Improve the internal density of AlSiC composite materials and avoid the generation of internal shrinkage cavities.

A riser heating body 6 is fixedly inserted into the interior of the partition plate 5 in the reaction kettle.

A liquid riser 7 is fixedly inserted into the inside of the liquid riser heating body 6 .

in:

A. A cooling water channel is provided inside the clapboard 5 in the reaction kettle, and a structure for installing the riser heating body 6 and the riser pipe 7 is left in the middle part.

B. The riser pipe heating body 6 is used to heat and keep warm the riser pipe 7, so as to ensure the unobstructed flow passage inside the riser pipe 7. During the differential pressure casting process, the thickness of the aluminum alloy wall inside the riser pipe 7 is constant and the flow passage is not blocked. After the mold is filled, the aluminum alloy liquid 12 inside the riser tube 7 can smoothly flow back into the crucible without affecting the next differential pressure casting.

C. The riser pipe 7 is used to provide an ascending channel for the aluminum alloy liquid 12 under the action of the pressure difference between the upper and lower reactors, and connect the gate of the mold with the aluminum alloy liquid 12 inside the crucible.

The bottom of the partition 5 in the reaction kettle is provided with a lower tank body 8 of the reaction kettle;

The upper left part of the lower tank body 8 of the reaction kettle is provided with a gas inlet 8-1 of the lower tank body of the reaction kettle for connecting the gas inlet of the lower tank body 8 of the reaction kettle to an external compressed gas tank and introducing compressed gas;

The lower right part of the lower tank body 8 of the reactor runs through a lower tank body safety valve 8-2 for discharging excess gas and releasing pressure inside the tank body.

in:

A. The air inlet 8-1 of the lower tank of the reactor is used to connect the external compressed gas tank, introduce compressed gas, apply pressure to the aluminum alloy liquid 12 inside the crucible inside the reactor, and form a pressure difference with the upper tank of the reactor, so as to realize differential pressure. Die casting or anti-gravity casting.

B. The safety valve 8-2 of the lower tank of the reactor is used to discharge excess gas when the internal pressure of the reactor reaches a safe value, and relieve the internal pressure of the tank to ensure safety and smooth progress of differential pressure casting.

Also includes aluminum alloy liquid 12;

Graphite crucible 11 for melting and smelting aluminum alloy and keeping the aluminum alloy liquid 12 warm;

A heating wire 10 for heating the graphite crucible 11 inside the lower tank body 8 of the reactor;

Fire wall 9 for fixing heating wire 10 and heat preservation.

in:

A. The heating wire 10 is used to heat the graphite crucible 11 inside the lower tank body 8 of the reaction kettle to melt and smelt the aluminum alloy, or only heat the aluminum alloy liquid 12 (with external aluminum alloy melting and smelting equipment).

B. The graphite crucible 11 is used for melting and smelting aluminum alloy, and keeping the aluminum alloy liquid 12 warm. It can also be used in conjunction with independent aluminum alloy melting and smelting equipment. The graphite crucible 11 is only used as a holding furnace for the aluminum alloy liquid 12.

C. Aluminum alloy liquid 12 is the raw material for differential pressure casting.

The working process of above-mentioned embodiment is as follows:

1. The aluminum alloy needs to be melted and smelted, and the raw material remains in the graphite crucible 11;

2. Install the riser pipe 7 in place, connect and close the upper bracket 1, the partition plate 5 in the reactor and the lower tank 8 of the reactor; as shown in Figure 2

3. The SiC prefabricated part is installed in the forming mold 3, and the forming mold 3 is heated through the upper cover 2 of the reaction kettle to provide a suitable temperature environment for the filling of the aluminum alloy liquid 12 in the differential pressure casting process; as shown in Figures 3 and 4 Show

4. By introducing pressure gas into the lower tank body 8 of the reaction kettle, under the action of pressure, the aluminum alloy liquid 12 in the graphite crucible 11 passes through the liquid riser 7 to fill the cavity in the mold 3; Under the environment, the tiny pores inside the SiC preform can be filled to complete the differential pressure casting process of aluminum alloy. As shown in Figure 5

5. After the aluminum alloy liquid 12 is filled, control and open the solenoid valve 5-1 of the inner cooling pipeline of the partition in the reaction kettle, and pass in the cooling liquid to realize the cooling of the bottom of the mold 3; from the bottom to the top, the program controls the opening The electromagnetic valves of the internal cooling pipeline 2-2 of the upper cover of the reaction kettle are fed with cooling liquid one by one; through the above cooling control, the temperature gradient changes from the bottom to the top of the mold 3, and from the outside to the center flow channel can be formed to realize product orientation inside the mold cavity Solidification, under the action of pressure, realizes shrinkage, and gradually transfers the shrinkage cavity to the center runner and top gate, improves the compactness of the casting, and reduces the generation of shrinkage cavity.

6. After the feeding is completed, the upper bracket 1 moves the upper cover 2 of the reactor upward under the action of the hydraulic mechanical lifting mechanism of the upper bracket 1 to realize demoulding;

7. Take out the AlSiC product, clean the mold 3, and start the next differential pressure casting cycle.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. A directional solidification equipment for differential pressure casting of aluminum silicon carbide, characterized in that: it includes a reaction kettle upper cover (2) for heat preservation and pressure maintaining of the mold, realizing differential pressure filling and directional solidification of the aluminum alloy liquid; The inside of the reactor upper cover (2) is provided with a heating wire (2-1) inside the reactor upper cover for heating and insulating the mold; The inside of the reactor upper cover (2) is provided with an internal cooling pipeline (2-2) of the reactor upper cover for realizing directional cooling of the mould. 2. A kind of AlSiC differential pressure casting directional solidification equipment according to claim 1, characterized in that: an upper bracket (1) is arranged on the outside of the reactor upper cover (2), and the upper bracket (1 ) contains hydraulic (mechanical) lifting and lowering mechanisms. 3 . The directional solidification equipment for aluminum silicon carbide differential pressure casting according to claim 1 , characterized in that: a mold ( 3 ) for forming AlSiC composite material is placed inside the upper cover ( 2 ) of the reaction kettle. 4 . 4. A kind of aluminum silicon carbide differential pressure casting directional solidification equipment according to claim 3, it is characterized in that: the inside of described mold (3) is provided with SiC prefabricated body (4), and SiC prefabricated body (4) passes through different The granular SiC powder is formed by pressing (or firing), and the surface and interior have a connected porous structure. During the differential pressure casting process, the aluminum alloy liquid fills the internal pores of the SiC preform and solidifies to form an AlSiC composite material. 5. A kind of aluminum silicon carbide differential pressure casting directional solidification equipment according to claim 2, characterized in that: the bottom of the upper support (1) is provided with a support mold (3) and the upper support (1) A partition (5) in the reaction kettle, and a cooling pipeline (5-1) inside the partition in the reaction kettle is arranged inside the reaction kettle with the middle partition (5). 6 . The directional solidification equipment for aluminum silicon carbide differential pressure casting according to claim 5 , characterized in that: a riser heating body ( 6 ) is fixedly plugged inside the partition ( 5 ) in the reaction kettle. 6 . 7 . The directional solidification equipment for AlSiC differential pressure casting according to claim 6 , characterized in that: a riser pipe ( 7 ) is fixedly inserted inside the riser pipe heating body ( 6 ). 8. A kind of aluminum silicon carbide differential pressure casting directional solidification equipment according to claim 7, characterized in that: the interior of the partition (5) in the reaction kettle is provided with a cooling water channel, and the middle part is left to install a riser The structure of heating body (6) and riser pipe (7). 9. A kind of aluminum silicon carbide differential pressure casting directional solidification equipment according to claim 5, characterized in that: the bottom of the partition (5) in the reaction kettle is provided with a lower tank body (8) of the reaction kettle; The upper left part of the lower tank body (8) of the reaction kettle is provided with a lower tank body gas port (8-1) for connecting the gas inlet of the lower tank body (8) of the reaction kettle to an external compressed gas tank and introducing compressed gas; The lower right part of the lower tank body (8) of the reaction kettle is penetrated with a safety valve (8-2) for the lower tank body of the reaction kettle used for discharging excess gas and releasing pressure inside the tank body. 10. A kind of aluminum silicon carbide differential pressure casting directional solidification equipment according to claim 9, characterized in that: it also includes aluminum alloy liquid (12); A graphite crucible (11) for melting and smelting aluminum alloys and keeping the aluminum alloy liquid (12) warm; A heating wire (10) for heating the inner crucible of the lower tank body (8) of the reaction kettle; Fire wall (9) for fixing heating wire (10) and heat preservation.

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