Multifunctional casting method and device

Abstract

The present invention belongs to the field of casting technology and provides a multifunctional casting method and apparatus. On the one hand, a protective atmosphere is added during the casting process to prevent oxidation of the liquid aluminum alloy and the solid iron matrix. On the other hand, in-situ heat treatment is performed to achieve stress relief annealing and reduce interfacial stress concentration. The present invention integrates the casting and heat treatment operations, avoiding interfacial cracking caused by rapid temperature drop during the transfer of the casting and avoiding cracking of the bimetallic interface. At the same time, by adjusting the atmosphere in the casting chamber during casting, the present invention can mark entrained structure oxide film defects during the casting process.

Description

Technical Field

[0001] The present invention belongs to the field of casting technology, and specifically relates to a multifunctional casting method and device, and more specifically to a casting method and device that integrates casting atmosphere protection, in-situ heat treatment, and defect marking functions. Background Art

[0002] The rapid development of the aerospace and weapons sectors has placed increasingly stringent demands on the metallurgical quality and service performance of complex aluminum alloy castings. Aluminum alloy castings urgently need to transform toward integrated structural and functional capabilities. Consequently, bimetallic materials, such as aluminum / iron bimetallics, have emerged. These materials combine the lightweight advantages of aluminum alloys with the long lifespan of iron alloys, addressing the diverse performance requirements of different parts in complex aluminum alloy castings.

[0003] The traditional production method of aluminum / iron bimetallic complex castings is liquid-solid casting, that is, the molten aluminum alloy is cast onto the surface of a solid iron matrix to achieve an effective connection between the two dissimilar metals. However, under existing technical conditions, many problems are still faced. First, interface oxidation. Whether it is liquid aluminum alloy or solid iron matrix, both will produce varying degrees of oxidation in the high-temperature environment of casting, and their oxidation products directly isolate the dissimilar metals, causing cracking at the aluminum / iron bimetallic interface. Among the many casting defects, the inclusion structure oxide film defect is difficult to accurately detect in actual castings due to its hidden characteristics, which means that this type of defect becomes a potential hidden danger during the service of the casting. Second, stress concentration. Due to the difference in thermal expansion coefficients between aluminum and iron, the deformation amplitudes on both sides of the interface of the aluminum / iron bimetallic casting are different during the cooling and solidification process, so the stress concentration generated exacerbates the cracking of the interface. Therefore, if you want to produce qualified structural and functional integrated aluminum / iron bimetallic complex castings, the cracking problem of the bimetallic interface must be effectively controlled.

[0004] Existing liquid-solid casting technology for complex aluminum / iron bimetallic castings has always faced a difficult problem: interfacial cracking. Traditionally, this problem has been addressed by adding an intermediate layer to the surface of the solid iron matrix. While the addition of a non-oxidizable intermediate layer (such as Cr) has alleviated the interfacial oxidation problem to some extent, it has not fundamentally addressed the problem, particularly the oxidation of liquid aluminum alloys, which has never been controlled. Furthermore, while the intermediate layer isolates the aluminum and iron, somewhat mitigating interfacial cracking caused by the significant difference in thermal expansion coefficients between the two materials, it does not effectively alleviate stress concentration; it merely shifts the stress concentration from the aluminum-iron interface to the intermediate layer. This concentrated stress can lead to cracking in the casting under subsequent service conditions.

[0005] In summary, the two major issues facing liquid-solid casting of complex aluminum / iron bimetallic castings—interfacial oxidation and stress concentration—have not been fundamentally addressed under existing technologies. Furthermore, existing technologies lack a comprehensive approach to addressing the defects of entrained oxide films. This is why the present invention was proposed. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a multifunctional casting method and device.

[0007] According to one aspect of the present invention, the present invention provides the following technical solutions:

[0008] A multifunctional casting method comprises the following steps:

[0009] S1. Pre-place the iron matrix in the casting mold, then place the casting mold in the casting chamber, close the cover for sealing, position and assemble the casting crucible and the cover, and plug the pouring gate to seal;

[0010] S2. Turn on the heater and heat the mold at a heating rate of 5°C / min until the mold temperature is 200-400°C.

[0011] S3, maintaining the casting chamber in communication with the first gas source and the external environment for air washing, and after a period of air washing, cutting off the connection between the casting chamber and the external environment;

[0012] S4, injecting aluminum alloy liquid into the casting crucible, connecting the first gas source and the casting crucible for ventilation, starting the hydraulic cylinder to drive the plug rod to move the plug to open the gate, and the aluminum alloy liquid enters the casting mold to start casting and filling. After the aluminum alloy liquid has completely entered the casting mold, the connection between the casting chamber and the first gas source and the connection between the casting crucible and the first gas source are cut off; the casting mold is kept warm for 2 to 8 hours for stress relief annealing to obtain an aluminum / iron bimetallic casting;

[0013] Or the connection between the casting chamber and the first gas source is cut off, the second gas source and the casting chamber are connected for ventilation, the aluminum alloy liquid is injected into the casting crucible, the first gas source and the casting crucible are connected for ventilation, the hydraulic cylinder is started to drive the plug rod to move so that the plug opens the gate, the aluminum alloy liquid enters the casting mold and starts casting and filling the mold. After the aluminum alloy liquid has completely entered the casting mold, the connection between the casting chamber and the second gas source and the connection between the casting crucible and the first gas source are cut off; after the casting mold is kept warm for 2 to 8 hours for stress relief annealing, an aluminum / iron bimetallic casting with entrained structure oxide film defects is obtained.

[0014] According to another aspect of the present invention, the present invention provides the following technical solutions:

[0015] A multifunctional casting device, which includes a first gas source, a casting chamber and a casting crucible, wherein the first gas source is filled with atmosphere gas, one side of the casting chamber is connected to the first gas source, and the other side of the casting chamber is connected to the external environment, a casting mold is provided in the casting chamber, a heater is provided between the casting chamber and the casting mold, a cover is provided at the upper end of the casting chamber, the casting crucible is set on the cover through a pad, a gate is provided at the bottom of the casting crucible and is connected to the casting chamber, the gate is connected to the casting mold through a conveying pipe, the casting crucible is connected to the first gas source, a liquid level control device is provided in the casting crucible, the liquid level control device includes a hydraulic cylinder, a plug rod and a plug connected in sequence, the plug blocks the gate or opens the gate when driven by the plug rod; the casting chamber is also connected to a second gas source through a fifth valve, and the second gas source is filled with oxygen isotope gas.

[0016] The beneficial effects of the present invention are as follows:

[0017] The present invention proposes a multifunctional casting method and apparatus. This method, while adding a protective atmosphere during the casting process to prevent oxidation of the liquid aluminum alloy and the solid iron matrix, also implements in-situ heat treatment, achieving stress relief annealing and reducing interfacial stress concentration. This method integrates the casting and heat treatment operations, avoiding interfacial cracking caused by rapid temperature drops during casting transport and preventing cracking at the bimetallic interface. Furthermore, by adjusting the casting chamber atmosphere during casting, the present invention can mark entrained structure oxide film defects during the casting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 It is a structural schematic diagram of the casting device of the present invention.

[0020] Figure 2 Schematic diagram of the interface of the aluminum / iron bimetallic prepared in Example 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of the interface of the aluminum / iron bimetallic prepared in Comparative Example 1 of the present invention.

[0022] Figure 4 This is a schematic diagram of the interface of the aluminum / iron bimetallic prepared in Comparative Example 2 of the present invention.

[0023] In the figure: 1-first gas source, 2-casting chamber, 3-first valve, 4-second valve, 5-casting crucible, 6-third valve, 7-casting mold, 8-fourth valve, 9-cover, 10-sealing gasket, 11-lock, 12-pad, 13-heater, 14-hydraulic cylinder, 15-plug rod, 16-plug, 17-nozzle, 18-delivery pipeline, 19-second gas source, 20-fifth valve.

[0024] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0025] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] According to one aspect of the present invention, the present invention provides the following technical solutions:

[0027] A multifunctional casting method comprises the following steps:

[0028] S1. Pre-place the iron matrix in the casting mold, then place the casting mold in the casting chamber, close the cover for sealing, position and assemble the casting crucible and the cover, and plug the pouring gate to seal;

[0029] S2. Turn on the heater and heat the mold at a heating rate of 5°C / min until the mold temperature is 200-400°C.

[0030] S3, maintaining the casting chamber in communication with the first gas source and the external environment for air washing, and after a period of air washing, cutting off the connection between the casting chamber and the external environment;

[0031] S4, injecting aluminum alloy liquid into the casting crucible, connecting the first gas source and the casting crucible for ventilation, starting the hydraulic cylinder to drive the plug rod to move the plug to open the gate, and the aluminum alloy liquid enters the casting mold to start casting and filling. After the aluminum alloy liquid has completely entered the casting mold, the connection between the casting chamber and the first gas source and the connection between the casting crucible and the first gas source are cut off; the casting mold is kept warm for 2 to 8 hours for stress relief annealing to obtain an aluminum / iron bimetallic casting;

[0032] Or the connection between the casting chamber and the first gas source is cut off, the second gas source and the casting chamber are connected for ventilation, the aluminum alloy liquid is injected into the casting crucible, the first gas source and the casting crucible are connected for ventilation, the hydraulic cylinder is started to drive the plug rod to move so that the plug opens the gate, the aluminum alloy liquid enters the casting mold and starts casting and filling the mold. After the aluminum alloy liquid has completely entered the casting mold, the connection between the casting chamber and the second gas source and the connection between the casting crucible and the first gas source are cut off; after the casting mold is kept warm for 2 to 8 hours for stress relief annealing, an aluminum / iron bimetallic casting with entrained structure oxide film defects is obtained.

[0033] The present invention integrates casting, heat treatment, and defect marking. First, based on atmosphere protection during the casting process, oxidation of the liquid aluminum alloy and the solid iron matrix is ​​prevented, thereby preventing the oxidation products from affecting the bimetallic bond. Second, stress relief annealing of the aluminum-iron bimetallic is performed using in-situ heat treatment to eliminate interfacial cracks. During casting, oxygen isotope gases such as oxygen-18 or oxygen-17 are introduced into the casting chamber. During the casting process, an aluminum oxide film is produced. Using this isotope for marking can be used to study and analyze the entrained structure oxide film defects and their formation mechanisms in castings.

[0034] Preferably, in step S1, the iron substrate is pretreated before being placed in the mold, specifically: first, it is pickled with 5wt% hydrochloric acid to remove rust, and then ultrasonically cleaned with alcohol for 5 minutes; secondly, it is alkaline washed with 5wt% NaOH aqueous solution to remove rust, and then ultrasonically cleaned with alcohol for 5 minutes; finally, it is soaked in 8-15wt% ZnCl2 aqueous solution for 8-12 minutes, and then dried at 200-270°C for 3-5 minutes. Through the above operation, the surface oxide layer of the iron substrate can be removed, and a layer of ZnCl2 is retained on the surface of the iron substrate to isolate secondary oxidation. At the same time, ZnCl2 can be quickly melted in the subsequent casting process, and the molten ZnCl2 will be carried away with the liquid front and will not stay at the bimetallic interface position, so it will not affect the bimetallic interface performance.

[0035] Preferably, in step S3, the scrubbing time is 2 to 3 minutes.

[0036] Preferably, in step S4, the stress relief annealing is followed by furnace cooling at a cooling rate of 20-50° C. / h.

[0037] Preferably, the iron matrix is ​​QT500, and the aluminum alloy liquid is ZL114A, ZL702A or ZL205A alloy liquid.

[0038] Preferably, the first gas source provides atmosphere gas, and the atmosphere gas is argon, sulfur dioxide, or sulfur hexafluoride.

[0039] Preferably, the second gas source provides oxygen isotope gas (oxygen-18 or oxygen-17 isotope gas).

[0040] According to another aspect of the present invention, the present invention provides the following technical solutions:

[0041] See also Figure 1 A multifunctional casting device, the device includes a first gas source 1, a casting chamber 2 and a casting crucible 5, the first gas source 1 is filled with atmospheric gas, one side of the casting chamber 2 is connected to the first gas source 1, and the other side of the casting chamber 2 is connected to the external environment, a casting mold 7 is provided in the casting chamber 2, a heater 13 is provided between the casting chamber 2 and the casting mold 7, for providing heat to the casting mold and the casting solidified inside, a cover 9 is provided at the upper end of the casting chamber 2, the casting crucible 5 is arranged on the cover 9 through a pad 12, the casting crucible 5 A gate is provided at the bottom and is connected to the casting chamber 2. The gate is connected to the mold 7 through a conveying pipe 18. The casting crucible 5 is connected to the first gas source 1. A liquid level control device is provided in the casting crucible 5. The liquid level control device includes a hydraulic cylinder 14, a plug rod 15 and a plug 16 connected in sequence. The plug 16 blocks or opens the gate under the drive of the plug rod 15. The casting chamber is also connected to a second gas source 19 through a fifth valve. The second gas source 19 is filled with oxygen isotope gas (oxygen 18 or oxygen 17 isotope gas).

[0042] Preferably, the casting chamber 2 and the cover 9 are connected by a lock 11 , and a sealing gasket 10 is provided between the casting chamber 2 and the cover 9 .

[0043] Preferably, the first gas source 1 is connected to the casting chamber 2 through a pipeline, and the pipeline includes a first pipeline and a second pipeline arranged above and below. The first pipeline faces the casting chamber 2 and adopts a large flow rate to supply air to achieve atmosphere control during the casting process. A first valve 3 is provided on the first pipeline; the second pipeline faces the casting mold 7 and adopts a small flow rate to supply air to ensure that the residual air inside the casting mold is exhausted. A second valve 4 is provided on the second pipeline.

[0044] Preferably, the first gas source 1 is connected to the casting crucible 5 through a third pipe, a third valve 6 is provided on the third pipe, and a nozzle 17 is provided at the end of the third pipe in the casting crucible 5.

[0045] Preferably, the casting chamber 2 is connected to the external environment through a fourth pipe, and a fourth valve 8 is provided on the fourth pipe.

[0046] The technical solution of the present invention is further described below with reference to specific embodiments.

[0047] The iron substrate of the following embodiments and comparative examples is QT500, and the iron substrate is pretreated before being placed in the casting mold, specifically: first, it is pickled with 5wt% hydrochloric acid to remove rust, and then ultrasonically cleaned with alcohol for 5 minutes; secondly, it is alkaline washed with 5wt% NaOH aqueous solution to remove rust, and then ultrasonically cleaned with alcohol for 5 minutes; finally, it is soaked in 10wt% ZnCl2 aqueous solution for 10 minutes and then dried at 230°C for 3 minutes.

[0048] Example 1

[0049] A casting method for aluminum / iron bimetallic castings, the specific steps are as follows:

[0050] S1. Pre-place the iron substrate in a casting mold, then place the casting mold in a casting chamber, close the cover, seal it with a gasket to prevent air leakage, and lock the casting chamber and the cover with a lock; use a pad to position and assemble the casting crucible and the casting chamber cover; and plug the pouring gate with a plug;

[0051] S2. Turn on the heater and increase the temperature in the casting chamber at a heating rate of 5°C / min until the temperature in the mold reaches 300°C;

[0052] S3. Open the first valve, the second valve, and the fourth valve at the same time, introduce argon gas for purge to remove the initial atmosphere. After purge for 2 minutes, close the fourth valve first and then the second valve, while keeping the first valve normally open.

[0053] S4. Inject ZL114A aluminum alloy liquid into the casting crucible until the liquid level is 5 cm lower than the nozzle, open the third valve and pass the argon gas in the first gas source into the casting crucible through the nozzle to protect the liquid level, start the hydraulic cylinder to drive the plug rod to move vertically upward, and the plug leaves the pouring mouth of the casting crucible. The aluminum alloy liquid in the casting crucible enters the mold in the casting chamber through the pouring mouth. After all the aluminum alloy liquid enters, close the first valve and the third valve; then keep the mold at 300°C for 3 hours through the heater for stress relief annealing, and cool it with the furnace (cooling rate is 50°C / h) to obtain an aluminum / iron bimetallic casting.

[0054] After the casting is completed, the mold is taken out from the casting chamber to obtain an aluminum / iron bimetallic casting, such as Figure 1 As shown, there is no defect at the interface of the aluminum / iron bimetallic casting, and the bonding strength is tested to be 62 MPa.

[0055] Example 2

[0056] A casting method for aluminum / iron bimetallic castings, the specific steps are as follows:

[0057] S1. Pre-place the iron substrate in a casting mold, then place the casting mold in a casting chamber, seal it with a gasket to prevent air leakage, and lock the casting chamber and the cover with a lock; use a pad to position and assemble the casting crucible and the casting chamber cover; and plug the pouring gate with a plug;

[0058] S2. Turn on the heater and increase the temperature in the casting chamber at a heating rate of 5°C / min until the temperature in the mold reaches 200°C;

[0059] S3. Open the first, second, and fourth valves simultaneously, introduce sulfur dioxide for scrubbing to remove the initial atmosphere. After scrubbing for 3 minutes, close the fourth valve first and then the second valve, while keeping the first valve normally open.

[0060] S4. Inject ZL702A aluminum alloy liquid into the casting crucible until the liquid level is 5 cm lower than the nozzle, open the third valve to pass sulfur dioxide in the first gas source into the casting crucible through the nozzle to protect the liquid level, start the hydraulic cylinder to drive the plug rod to move vertically upward, the plug leaves the pouring mouth of the casting crucible, and the aluminum alloy liquid in the casting crucible enters the mold in the casting chamber through the pouring mouth. After all the aluminum alloy liquid enters, close the first valve and the third valve; then keep the mold at 200°C for 8 hours through a heater for stress relief annealing, and then cool it with the furnace (cooling rate is 20°C / h) to obtain an aluminum / iron bimetallic casting.

[0061] Example 3

[0062] A casting method for aluminum / iron bimetallic castings, the specific steps are as follows:

[0063] S1. Pre-place the iron substrate in a casting mold, then place the casting mold in a casting chamber, seal it with a gasket to prevent air leakage, and lock the casting chamber and the cover with a lock; use a pad to position and assemble the casting crucible and the casting chamber cover; and plug the pouring gate with a plug;

[0064] S2. Turn on the heater and increase the temperature in the casting chamber at a heating rate of 5°C / min until the temperature in the mold reaches 400°C;

[0065] S3. Open the first, second, and fourth valves simultaneously, introduce sulfur hexafluoride for gas washing to remove the initial atmosphere. After washing for 2 minutes, close the fourth valve first and then the second valve, while keeping the first valve normally open.

[0066] S4. Inject ZL705A aluminum alloy liquid into the casting crucible until the liquid level is 5 cm lower than the nozzle, open the third valve and pass sulfur hexafluoride in the first gas source into the casting crucible through the nozzle to protect the liquid level, start the hydraulic cylinder to drive the plug rod to move vertically upward, the plug leaves the pouring mouth of the casting crucible, and the aluminum alloy liquid in the casting crucible enters the mold in the casting chamber through the pouring mouth. After all the aluminum alloy liquid enters, close the first valve and the third valve; then keep the mold at 400°C for 2 hours through the heater for stress relief annealing, and cool it with the furnace (cooling rate is 30°C / h) to obtain an aluminum / iron bimetallic casting.

[0067] Example 4

[0068] A casting method for aluminum / iron bimetallic castings, the specific steps are as follows:

[0069] S1. Pre-place the iron substrate in a casting mold, then place the casting mold in a casting chamber, seal it with a gasket to prevent air leakage, and lock the casting chamber and the cover with a lock; use a pad to position and assemble the casting crucible and the casting chamber cover; and plug the pouring gate with a plug;

[0070] S2. Turn on the heater and increase the temperature in the casting chamber at a heating rate of 5°C / min until the temperature in the mold reaches 300°C;

[0071] S3. Open the first valve, the second valve, and the fourth valve at the same time, introduce argon gas for purge to remove the initial atmosphere. After purge for 3 minutes, close the fourth valve first, and then close the second valve and the first valve.

[0072] S4. Inject ZL702A aluminum alloy liquid into the casting crucible until the liquid level is 5 cm lower than the nozzle, open the third valve to pass the argon gas in the first gas source into the casting crucible through the nozzle to protect the liquid level, open the fifth valve to pass the oxygen-18 isotope gas, start the hydraulic cylinder to drive the plug rod to move vertically upward, the plug leaves the pouring mouth of the casting crucible, and the aluminum alloy liquid in the casting crucible enters the mold in the casting chamber through the pouring mouth. After all the aluminum alloy liquid enters, close the third valve and the fifth valve; then, keep the mold at 300°C for 3 hours through a heater for stress relief annealing, and then cool it with the furnace (cooling rate is 40°C / h) to obtain an aluminum / iron bimetallic casting with oxide film defects labeled with oxygen-18 isotope.

[0073] After the casting is completed, the mold is removed from the casting chamber to obtain an aluminum alloy casting labeled with the oxygen-18 isotope. By dissecting the casting, the entrained structure oxide film defects can be found and isotope analysis can be performed to facilitate the study of oxide film defects and their formation mechanism.

[0074] Comparative Example 1

[0075] The device of the present invention is used for casting, but the first gas source is not turned on for atmosphere protection and the heater is not turned on for in-situ heating during the casting process. The remaining steps are the same as those in Example 1. The aluminum / iron bimetallic casting obtained is as follows Figure 3 As shown, it can be seen that there is obvious cracking at the interface, and the bonding strength is measured to be <10MPa.

[0076] Comparative Example 2

[0077] The device of the present invention is used for casting, but the first gas source is not opened for atmosphere protection during the casting process. The remaining steps are the same as those in Example 1. The aluminum / iron bimetallic casting obtained is as follows: Figure 4 As shown, elemental analysis of its interface revealed the presence of aluminum oxide. This indicates that if only in-situ heating is performed without atmosphere protection, the interface of the resulting casting will also crack due to defects in the oxide film incorporated during the casting process.

[0078] It can be seen from the above embodiments and comparative examples that the present invention is used for casting. On the one hand, a protective atmosphere is added during the casting process to avoid oxidation of the liquid aluminum alloy and the solid iron matrix. On the other hand, in-situ heat treatment is achieved to realize stress relief annealing, reduce interface stress concentration, and solve the problem of interface cracking of aluminum / iron bimetallic castings. At the same time, the present invention can also introduce oxygen isotope gas to mark oxide film defects and analyze the entrained structure oxide film defects and their formation mechanism.

[0079] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A multifunctional casting method, characterized in that: The multifunctional casting device used includes a first gas source, a casting chamber and a casting crucible, wherein the first gas source is filled with atmospheric gas, one side of the casting chamber is connected to the first gas source, and the other side of the casting chamber is connected to the external environment, a casting mold is provided in the casting chamber, a heater is provided between the casting chamber and the casting mold, a cover is provided at the upper end of the casting chamber, the casting crucible is set on the cover through a pad, a pouring gate is provided at the bottom of the casting crucible and is connected to the casting chamber, the pouring gate is connected to the casting mold through a conveying pipe, the casting crucible is connected to the first gas source, a liquid level control device is provided in the casting crucible, the liquid level control device includes a hydraulic cylinder, a plug rod and a plug connected in sequence, the plug blocking or opening the pouring gate when driven by the plug rod; the casting chamber is also connected to a second gas source through a fifth valve; The steps include: S1. Pre-place the iron matrix in the casting mold, then place the casting mold in the casting chamber, close the cover for sealing, position and assemble the casting crucible and the cover, and plug the pouring gate to seal; S2, turning on the heater to heat the mold; S3, maintaining the casting chamber in communication with the first gas source and the external environment for air washing, and after a period of air washing, cutting off the connection between the casting chamber and the external environment; S4, injecting aluminum alloy liquid into the casting crucible, connecting the first gas source and the casting crucible for ventilation, cutting off the connection between the casting chamber and the first gas source, connecting the second gas source and the casting chamber for ventilation, starting the hydraulic cylinder to drive the plug rod to move so that the plug opens the gate, and the aluminum alloy liquid enters the casting mold to start casting and filling the mold. After the aluminum alloy liquid has completely entered the casting mold, cutting off the connection between the casting chamber and the second gas source and the connection between the casting crucible and the first gas source; after the casting mold is kept warm and subjected to stress relief annealing, an aluminum / iron bimetallic casting having an entrained structure oxide film defect is obtained; The first gas source provides atmosphere gas, which is argon, sulfur dioxide, or sulfur hexafluoride; the second gas source provides oxygen isotope gas.

2. The multifunctional casting method according to claim 1, characterized in that: The iron matrix is ​​pretreated before being placed in the mold. Specifically, it is first pickled with hydrochloric acid to remove rust and then ultrasonically cleaned with alcohol; secondly, it is alkaline washed with NaOH aqueous solution to remove rust and then ultrasonically cleaned with alcohol; finally, it is soaked in an 8-15wt% ZnCl2 aqueous solution for 8-12 minutes and then dried at 200-270℃ for 3-5 minutes.

3. The multifunctional casting method according to claim 1, characterized in that: The gas washing time is 2~3 minutes.

4. The multifunctional casting method according to claim 1, characterized in that: After stress relief annealing, the steel is cooled in the furnace at a cooling rate of 20~50℃ / h.

5. The multifunctional casting method according to claim 1, characterized in that: The iron matrix is ​​QT500, and the aluminum alloy liquid is ZL114A, ZL702A or ZL205A alloy liquid.

6. The multifunctional casting method according to claim 1, characterized in that: The casting chamber and the cover are connected by a lock, and a sealing gasket is provided between the casting chamber and the cover.

7. The multifunctional casting method according to claim 1, characterized in that: The first gas source is connected to the casting chamber through a pipeline, which includes a first pipeline and a second pipeline arranged above and below. The first pipeline faces the casting chamber and is provided with a first valve; the second pipeline faces the casting mold and is provided with a second valve; the first gas source is connected to the casting crucible through a third pipeline, which is provided with a third valve, and a nozzle is provided at the end of the third pipeline in the casting crucible.

8. The multifunctional casting method according to claim 1, characterized in that: The casting chamber is connected to the external environment through a fourth pipeline, and a fourth valve is provided on the fourth pipeline.

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