Precise gravity casting magnesium alloy production line and control process thereof

Abstract

The invention relates to a precision gravity casting magnesium alloy production line and a control technology thereof.The magnesium alloy production line comprises a melting casting system, a production system and an air supply system which work in a matched mode, the production system comprises a sand mold conveying line and a sand mold box conveyed by the sand mold conveying line, and the sand mold box comprises a box body, a pouring cup and a dead head, the box body is filled with molding sand, a molding cavity is reserved in the molding sand, a pouring gate is reserved in the molding cavity at the position of the pouring cup, the production system further comprises a station box covering the sand mold conveying line, and a riser cover, a pouring cup cover and a ventilation plug which are connected with an air supply system and can be matched with the riser, the pouring cup and the pouring gate respectively are arranged in the station box; the protection gas can be conveyed to the forming cavity through the riser cover and the ventilation plug, pre-protection is achieved, gas protection in the casting process can be achieved through the pouring cup cover, the purity of magnesium alloy is effectively guaranteed, and the forming quality of magnesium alloy castings is optimized.

Description

Technical Field

[0001] This invention belongs to the field of metal casting technology, specifically relating to a precision gravity casting magnesium alloy production line and its control process. Background Technology

[0002] In sand casting, risers and pouring cups are typically used for feeding to reduce defects such as shrinkage cavities, porosity, and inaccurate dimensions in the castings. For magnesium alloy melt, sulfur powder is usually sprinkled on the surface of the liquid in the risers and pouring cups to prevent oxidation and combustion during casting. This inevitably leads to deviations in alloy composition and residual impurities that affect alloy performance. At the same time, the production process is inefficient, dangerous, and labor-intensive, and the produced magnesium alloy castings cannot meet the high-performance requirements of some high-standard fields. Summary of the Invention

[0003] To address the technical problems existing in the background art, the present invention provides a precision gravity casting magnesium alloy production line and its control process.

[0004] The technical solution of the present invention is as follows: The present invention first provides a precision gravity casting magnesium alloy production line, including a melting and casting system, a production system and a gas supply system that work together. The melting and casting system is configured to complete the melting of magnesium alloy and the casting at the production system location. The gas supply system is configured to supply protective gas to the production system during casting.

[0005] As the core technical concept of this invention, the production system includes a sand mold conveyor line capable of transporting sand mold boxes, and a casting station located in the middle of the sand mold conveyor line; the sand mold box includes a box body and a pouring cup and a riser on its upper side, the box body is filled with molding sand, the molding sand has a pre-reserved forming cavity, and the forming cavity has a pre-reserved pouring gate at the pouring cup position; the casting station includes a station box covered on the sand mold conveyor line, the station box has a sand mold inlet and outlet door opened along the conveying direction of the sand mold conveyor line, the station box is also equipped with a riser cover, a pouring cup cover and a vent plug that can be connected to the gas supply system, and the station box is also equipped with a plug ball that can control the sealing / opening of the pouring gate by movement; the riser cover is configured to cooperate with the riser to complete the conveying of protective gas from the riser to the forming cavity, the pouring cup cover is configured to cooperate with the pouring cup to complete the conveying of protective gas to the pouring cup, and the vent plug is configured to cooperate with the pouring gate to complete the conveying of protective gas from the pouring gate to the forming cavity.

[0006] Based on the above structure, the sand mold box can enter the workstation box through the sand mold inlet / outlet. Through the cooperation of the air supply system, riser cover, and vent plug, protective gas can be injected into the molding cavity in advance to expel the air in the molding cavity. Then, by removing the vent plug and quickly sealing the gate, the protective gas in the molding cavity is ensured not to escape. The pouring cup cover can continuously supply protective gas into the pouring cup. The molten magnesium alloy can be filled into the pouring cup in advance through the molten casting system. Then, by quickly removing the vent plug, the molten magnesium alloy in the pouring cup can flow into the molding cavity through the gate. With the continuous casting of the molten casting system, the gas protection during the casting process is achieved through the pouring cup cover, which effectively ensures the purity of magnesium alloy and optimizes the molding quality of magnesium alloy castings.

[0007] As described above, in order to facilitate the connection of riser caps, pouring cup caps, and vent plugs with the gas supply system to receive protective gas, each of the riser caps, pouring cup caps, and vent plugs is equipped with a gas connection connector that communicates with the gas supply system.

[0008] Specifically, regarding the gas supply structure of the riser cover, the riser cover includes a cover plate with an observation window in its middle, through which the casting status can be observed and the casting end time can be determined. A gas supply network is provided on the lower side of the cover plate, and several air outlets are opened on the lower side of the gas supply network. The gas connection connector passes through the middle of the cover plate and is connected to the gas supply channel.

[0009] As a preferred embodiment, in order to facilitate the matching of the riser cover and the riser and ensure the stability of the protective gas provided by the riser cover, the lower circumferential side of the cover plate is provided with a number of limiting blocks that can match the upper side of the riser.

[0010] As a further preferred embodiment, to facilitate the disassembly, assembly, and storage of the riser cover, two first handles are provided on the upper side of the cover plate.

[0011] In a further preferred embodiment, in order to accurately determine the casting time through the observation window and thus ensure the forming quality of the casting, the observation windows are arranged in multiple rows, with the positions of adjacent rows of observation windows staggered.

[0012] As described above, in a precision gravity casting magnesium alloy production line, specifically regarding the gas supply structure of the pouring cup lid, it includes a square frame-shaped gas supply pipe frame that can fit with the upper end of the pouring cup and is connected to the gas outlet pipe. The inner circumference of the gas supply pipe frame is provided with a plurality of distributed vent pipes with gas outlets facing the inside of the pouring cup.

[0013] As a preferred embodiment, to facilitate the disassembly, assembly, and storage of the pouring cup lid, two second handles are provided on the upper side of the gas supply pipe rack.

[0014] As described above, a precision gravity casting magnesium alloy production line includes, specifically, a gas supply system comprising two gas cylinders containing a CO2 gas source and an SF6 gas source, and a gas mixing and pressurizing tank connected to the two gas cylinders via two first pressure control gas lines. The gas mixing and pressurizing tank is connected to a gas line connector via a second pressure control gas line. This gas supply method ensures that the gas supply system can adapt to stable gas supply operations at multiple workstations. Furthermore, the method of pre-gathering the gas sources into the gas mixing and pressurizing tank according to the mixing ratio before centralized gas supply ensures the adjustability and uniformity of the mixed gas composition.

[0015] This invention also provides a control process for a magnesium alloy production line. Based on the above-mentioned precision gravity casting magnesium alloy production line, the control process specifically includes the following steps: S1. Start the sand mold conveyor line. Open the sand mold inlet / outlet door on the workstation box until the sand mold box enters the workstation box. Then, stop the sand mold conveyor line and close the sand mold inlet / outlet door. S2. Reset the riser cap, pouring cup cap, and vent plug to the top of the riser, the top of the pouring cup, and inside the pouring gate, respectively. S3, Gas protection; S3.1 The gas supply system works by sending the mixed gas into the molding cavity through the riser cover and the vent plug. After a preset time, the vent plug is removed and the plug ball is quickly reset to the gate position to seal the gate. S3.2 The gas supply system continuously delivers mixed gas into the pouring cup through the pouring cup cover to provide gas protection for the casting process; S4, casting; S4.1, The molten magnesium alloy is poured into the pouring cup during the operation of the molten magnesium alloy system. After the pouring cup is filled with molten magnesium alloy, the plug ball is quickly removed. S4.2 Continuously pour molten magnesium alloy into the pouring cup until the molten magnesium alloy can be observed through the riser cap, then stop pouring and proceed with the feeding process; S5. The gas supply system stops working, the riser cover and pouring cup cover are removed, the sand mold inlet and outlet gates are opened, the sand mold conveyor line works periodically, and steps S2-S4 are repeated to achieve continuous casting of magnesium alloy castings.

[0016] The beneficial effects of this invention are as follows: This invention provides a precision gravity casting magnesium alloy production line and its control process. The sand mold box can enter the workstation box through the sand mold inlet / outlet. Through the cooperation of the gas supply system, riser cover, and vent plug, protective gas can be injected into the forming cavity in advance to expel the air in the forming cavity. Then, by removing the vent plug and quickly sealing the gate, the protective gas is ensured not to escape in the forming cavity. The pouring cup cover can continuously supply protective gas into the pouring cup. The molten magnesium alloy can be pre-filled into the pouring cup through the melting and casting system. Then, by quickly removing the vent plug, the molten magnesium alloy in the pouring cup can flow into the forming cavity through the gate. With the continuous casting of the molten magnesium alloy system and the gas protection achieved by the pouring cup cover during the casting process, the purity of the magnesium alloy is effectively guaranteed, and the forming quality of the magnesium alloy casting is optimized. Attached Figure Description

[0017] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the attached diagram: Figure 1 This is a schematic diagram of the magnesium alloy production line in the embodiment; Figure 2 This is a schematic diagram of the molten casting system in the embodiment; Figure 3 This is a schematic diagram of the production system in the embodiment; Figure 4 This is a schematic diagram of the sand mold box in the embodiment; Figure 5 This is a top view of the riser cover in the embodiment; Figure 6 This is a schematic diagram of the structure of the observation window cover in the embodiment; Figure 7 This is a schematic diagram of the air supply structure of the riser cover in the embodiment; Figure 8 This is a schematic diagram of the pouring cup cap in the embodiment; Figure 9 This is a schematic diagram of the mating structure between the pouring cup cap and the pouring cup in the embodiment; Figure 10 This is a schematic diagram of the vent plug in the embodiment; Figure 11 This is a schematic diagram of the fit between the vent plug and the gate in the embodiment; Figure 12 This is a schematic diagram of the gas supply system in the embodiment; The components represented by the various reference numerals in the diagram are: 1. Melting and casting system; 11. Mobile vehicle; 12. Compensation drive mechanism; 13. Furnace; 2. Production system; 21. Sand mold conveyor line; 22. Sand mold box; 221. Box body; 222. Pour cup; 223. Pour gate; 224. Riser; 23. Casting station; 231. Station box; 232. Sand mold inlet / outlet door; 233. Opening / closing door; 234. Riser cover; 2341. Cover plate; 2342. First handle; 2343. Observation window; 2344. Observation window cover; 2345. Gas line connector; 2346. Gas supply network; 2347. Limiting block; 235. Casting cup cover; 2351. Gas supply pipe rack; 2352. Second handle; 2353. Distributed vent pipe; 236. Vent plug; 2361. Plug; 2362. Third handle; 3. Gas supply system; 31. Gas cylinder; 32. First pressure control gas line; 33. Mixed gas pressurization tank; 34. Second pressure control gas line. Detailed Implementation

[0019] To further understand the content of this invention, the invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0020] Example: This embodiment first provides a precision gravity casting magnesium alloy production line, see [link to documentation]. Figure 1 and Figure 12 The system includes a melting and casting system 1, a production system 2, and a gas supply system 3 that work together. The melting and casting system 1 is configured to complete the melting of magnesium alloy and the casting at the location of the production system 2. The gas supply system 3 is configured to supply protective gas to the production system 2 during casting. The structure of the magnesium alloy production line (the above-mentioned precision gravity casting magnesium alloy production line) will be described in detail below with reference to the accompanying drawings.

[0021] In this embodiment, combined with Figure 2 The melting and casting system 1 includes a moving track (not shown) arranged in parallel with the production system 2. A moving vehicle 11 is provided on the moving track. A furnace 13 is installed on the moving vehicle 11 through a compensation drive mechanism 12. The furnace 13 can realize the melting of magnesium alloy. The compensation drive mechanism 12 can drive the furnace 13 to move and tilt, thereby realizing the supply of magnesium alloy molten liquid to the production system 2.

[0022] In this embodiment, combined with Figure 3 The production system 2 includes a sand mold conveyor line 21 that can transport sand mold boxes 22. The sand mold conveyor line 21 is arranged in parallel with the moving track. In the middle, there is a casting station 23 that can be used for casting of sand mold boxes 22. In order to ensure casting production efficiency, multiple casting stations 23 are arranged linearly along the conveying direction of the sand mold conveyor line 21.

[0023] Combination Figure 4 First, regarding the structure of the sand mold box 22, it includes a box body 221 and a pouring cup 222 and a riser 224 located on the upper side of the box body 221. The box body 221 is filled with molding sand, and a molding cavity is reserved inside the molding sand. A pouring gate 223 is reserved in the molding cavity at the position of the pouring cup 222.

[0024] Based on the structure of sand mold box 22, combined with Figure 5 , Figure 8 and Figure 10 The casting station 23 includes a station box 231 covered on the sand mold conveying line 21. The station box 231 has a sand mold inlet / outlet door 232 opened along the conveying direction of the sand mold conveying line 21. The station box 231 is also equipped with a riser cover 234, a pouring cup cover 235 and a vent plug 236 that can be connected to the gas supply system 3. The station box 231 is also equipped with a plug ball that can be moved to control the sealing / opening of the pouring gate 223. The riser cover 234 is configured to cooperate with the riser 224 to complete the conveying of protective gas from the riser 224 to the molding cavity. The pouring cup cover 235 is configured to cooperate with the pouring cup 222 to complete the conveying of protective gas into the pouring cup 222. The vent plug 236 is configured to cooperate with the pouring gate 223 to complete the conveying of protective gas from the pouring gate 223 to the molding cavity.

[0025] Based on the above-described structure of the magnesium alloy production line, the sand mold box 22 can enter the workstation box 231 through the sand mold inlet / outlet door 232. Through the cooperation of the gas supply system 3, riser cover 234, and vent plug 236, protective gas can be pre-injected into the molding cavity to expel the air in the molding cavity. Then, by removing the vent plug 236 and quickly sealing the gate 223 with the plug ball, the protective gas is ensured not to escape in the molding cavity. The gate cup cover 235 can continuously supply protective gas into the gate cup 222. The molten magnesium alloy can be pre-filled into the gate cup 222 through the melting and casting system 1. Then, by quickly removing the plug ball, the molten magnesium alloy in the gate cup 222 can flow into the molding cavity through the gate 223. With the continuous casting of the melting and casting system 1, the gate cup cover 235 achieves gas protection during the casting process, effectively ensuring the purity of the magnesium alloy and optimizing the molding quality of the magnesium alloy castings.

[0026] In this embodiment, combined with Figure 6 , Figure 7 , Figure 9 and Figure 11To facilitate the connection of the riser cover 234, the pouring cup cover 235, and the vent plug 236 with the gas supply system 3 to receive protective gas, each of the riser cover 234, the pouring cup cover 235, and the vent plug 236 is provided with a gas connector 2345 that communicates with the gas supply system 3. The structure of the riser cover 234, the pouring cup cover 235, and the vent plug 236 will be described separately below.

[0027] Combination Figure 6 and Figure 7 Specifically, regarding the gas supply structure of the riser cover 234, the riser cover 234 includes a horizontally arranged rectangular cover plate 2341. A gas supply network 2346 is provided on the lower side of the cover plate 2341. Several air outlets are opened on the lower side of the gas supply network 2346. The gas connector 2345 passes through the middle of the cover plate 2341 and is connected to the gas supply channel. Through the connection of the gas connector 2345 with the gas supply system 3, the protective gas can be delivered to the riser 224 through the gas supply network 2346.

[0028] Furthermore, in order to facilitate the cooperation between the riser cover 234 and the riser 224 and ensure the stability of the protective gas provided through the riser cover 234, the lower circumferential side of the cover plate 2341 is provided with a plurality of limiting blocks 2347 that can cooperate with the upper side of the riser 224.

[0029] As a preferred embodiment of this invention, in order to facilitate the disassembly, assembly, and storage of the riser cover 234, two first handles 2342 are provided opposite each other on the upper side of the cover plate 2341.

[0030] As a further preferred embodiment, the cover plate 2341 has an observation window 2343 reserved in the middle. The casting status can be observed through the observation window 2343 to determine the casting end time. In order to accurately judge the casting time through the observation window 2343 and thus ensure the forming quality of the casting, multiple observation windows 2343 are arranged in a row along the length of the cover plate 2341, and multiple rows are provided, with the positions of adjacent rows of observation windows 2343 being staggered.

[0031] Preferably, in order to prevent the protective gas from escaping when it is supplied into the riser 224, and without affecting the observation of the level of the magnesium alloy melt in the riser 224 through the observation window 2343, an observation cover is also provided on the observation window 2343.

[0032] Combination Figure 9Specifically, the gas supply structure of the pouring cup cover 235 includes a square frame-shaped gas supply pipe bracket 2351 that can cooperate with the upper end of the pouring cup 222 and is connected to the gas outlet pipe. The inner circumference of the gas supply pipe bracket 2351 is provided with a plurality of distributed vent pipes 2353 with gas outlets facing the inside of the pouring cup 222. Through the connection of the gas supply system 3 with the gas pipe bracket 2345, the protective gas can be delivered into the pouring cup 222 through the gas supply pipe bracket 2351 and the distributed vent pipes 2353.

[0033] As a preferred embodiment of this invention, in order to facilitate the disassembly, assembly, and storage of the pouring cup cap 235, two second handles 2352 are provided on the upper side of the gas supply pipe rack 2351.

[0034] Combination Figure 11 Specifically, the structure of the vent plug 236 includes a plug 2361 that can cooperate with the gate 223. The air connector 2345 is located in the middle of the upper side of the plug 2361 and extends downward through the lower side of the plug 2361. Through the connection of the air connector 2345 with the air supply system 3, the protective gas can be delivered to the molding cavity through the gate 223.

[0035] As a preferred embodiment of this invention, in order to facilitate the disassembly, assembly, and storage of the vent plug 236, a third handle 2362 is also provided on the upper side of the plug 2361.

[0036] In this embodiment, combined with Figure 12 The gas supply system 3 includes two gas cylinders 31 containing CO2 and SF6 gas sources, and a gas mixing and boosting tank 33 connected to the two gas cylinders 31 via two first pressure control gas lines 32. The gas mixing and boosting tank 33 is connected to the gas line connector 2345 via a second pressure control gas line 34. This gas supply method ensures that the gas supply system 3 can adapt to stable gas supply operations at multiple workstations. At the same time, the method of pre-gathering the gas sources into the gas mixing and boosting tank 33 according to the mixing ratio before centralized gas supply ensures the adjustability and uniformity of the mixed gas composition.

[0037] This embodiment also provides a control process for a magnesium alloy production line. Based on the above-mentioned magnesium alloy production line, the control process specifically includes the following steps: S1. Start the sand mold conveyor line 21. The sand mold inlet / outlet door 232 on the workstation box 231 opens until multiple sand mold boxes 22 enter multiple workstation boxes 231 respectively. The sand mold conveyor line 21 stops and the sand mold inlet / outlet door 232 closes. Meanwhile, the furnace 13 of the melting and casting system 1 maintains a constant temperature of 750±10℃ for magnesium alloy refining through precise temperature control, the gas supply system 3 enters the standby state and is connected to the gas pipeline, and the molding cavity of the sand mold box 22 has been heated and sprayed with release agent. S2. Open the switch door 233 and reset the riser cover 234, the pouring cup cover 235 and the vent plug 236 to the upper side of the riser 224, the upper side of the pouring cup 222 and the inside of the pouring 223 respectively, and close the switch door 233. S3, Gas protection; S3.1 The gas supply system 3 works by sending the mixed gas into the molding cavity through the riser cover 234 and the vent plug 236. After a preset time, preferably 2±0.5s, the switch door 233 is opened, the vent plug 236 is removed, and the plug ball is quickly reset to the position of the gate 223 to seal the gate 223. Then the switch door 233 is closed. S3.2 The gas supply system 3 continuously supplies mixed gas into the pouring cup 222 through the pouring cup cover 235 to provide gas protection for the casting process; S4, casting; S4.1. The melting and casting system 1 pours magnesium alloy molten liquid into the pouring cups 222 of multiple sand mold boxes 22 in one operation. After the pouring cups 222 are filled with magnesium alloy molten liquid, the plug ball is quickly removed. S4.2 Continuously pour molten magnesium alloy into the pouring cup 222 until the molten magnesium alloy can be observed through the riser cap 234, then stop pouring and enter the feeding process for 10±5s; S5. The gas supply system 3 stops working, the riser cover 234 and the pouring cup cover 235 are removed, the sand mold inlet and outlet door 232 is opened, the sand mold conveyor line 21 works periodically, and steps S2-S4 are repeated to achieve continuous casting of magnesium alloy castings.

[0038] It should be noted that while the casting process is underway, magnesium alloy ingots need to be periodically replenished into the furnace 13 to maintain the magnesium alloy liquid level within a controllable range.

Claims

1. A precision gravity casting magnesium alloy production line, characterized in that, It includes a molten casting system (1), a production system (2), and a gas supply system (3) that work together. The melting and casting system (1) is configured to complete the melting of magnesium alloy and the casting at the production system (2), and the gas supply system (3) is configured to supply protective gas to the production system (2) during casting. The production system (2) includes a sand mold conveyor line (21) capable of transporting sand mold boxes (22), and a casting station (23) located in the middle of the sand mold conveyor line (21). The sand mold box (22) includes a box body (221) and a pouring cup (222) and a riser (224) on its upper side. The box body (221) is filled with molding sand, and a molding cavity is reserved inside the molding sand. A pouring gate (223) is reserved in the molding cavity at the position of the pouring cup (222). The casting station (23) includes a station box (231) covered on the sand mold conveying line (21). The station box (231) has a sand mold inlet / outlet door (232) opened along the conveying direction of the sand mold conveying line (21). The station box (231) is also equipped with a riser cover (234), a pouring cup cover (235) and a vent plug (236) that can be connected to the gas supply system (3). The station box (231) is also equipped with a plug ball that can be moved to control the gate (223) to be sealed / opened. The riser cap (234) is configured to cooperate with the riser (224) to complete the conveying of protective gas from the riser (224) to the molding cavity. The pouring cup cap (235) is configured to cooperate with the pouring cup (222) to complete the conveying of protective gas to the pouring cup (222). The vent plug (236) is configured to cooperate with the gate (223) to complete the conveying of protective gas from the gate (223) to the molding cavity.

2. The precision gravity casting magnesium alloy production line according to claim 1, characterized in that, The riser cap (234), pouring cup cap (235) and vent plug (236) are all equipped with a gas connector (2345) that is connected to the gas supply system (3).

3. The precision gravity casting magnesium alloy production line according to claim 2, characterized in that, The riser cover (234) includes a cover plate (2341) with an observation window (2343) reserved in the middle. The cover plate (2341) is provided with an air supply network (2346) on its lower side. The air supply network (2346) has several air outlets on its lower side. The air connector (2345) passes through the middle of the cover plate (2341) and is connected to the air supply channel.

4. The precision gravity casting magnesium alloy production line according to claim 3, characterized in that, The cover plate (2341) is provided with several limiting blocks (2347) on its lower circumferential side that can cooperate with the upper side of the riser (224).

5. A precision gravity casting magnesium alloy production line according to claim 3, characterized in that, The cover plate (2341) has two first handles (2342) facing each other on its upper side.

6. A precision gravity casting magnesium alloy production line according to claim 3, characterized in that, The observation windows (2343) are arranged in multiple rows, and the positions of adjacent rows of observation windows (2343) are staggered.

7. A precision gravity casting magnesium alloy production line according to claim 2, characterized in that, The pouring cup cover (235) includes a square frame-shaped air supply pipe bracket (2351) that can fit with the upper end of the pouring cup (222) and is connected to the air outlet pipe. The inner circumference of the air supply pipe bracket (2351) is provided with a plurality of distributed air outlets facing the inside of the pouring cup (222) and air outlet pipes (2353).

8. A precision gravity casting magnesium alloy production line according to claim 7, characterized in that, The upper side of the gas supply pipe rack (2351) is provided with two second handles (2352).

9. A precision gravity casting magnesium alloy production line according to claim 2, characterized in that, The gas supply system (3) includes two gas cylinders (31) containing a CO2 gas source and an SF6 gas source, and a gas mixing and booster tank (33) connected to the two gas cylinders (31) through two first pressure control gas lines (32). The gas mixing booster tank (33) is connected to the gas line connector (2345) through the second pressure control gas line (34).

10. A control process for a magnesium alloy production line, based on the precision gravity casting magnesium alloy production line according to any one of claims 2-9, characterized in that, Includes the following steps: S1. Start the sand mold conveyor line (21), open the sand mold inlet / outlet door (232) on the work station box (231) until the sand mold box (22) enters the work station box (231), stop the sand mold conveyor line (21), and close the sand mold inlet / outlet door (232); S2. Reset the riser cap (234), pouring cup cap (235), and vent plug (236) to the upper side of the riser (224), the upper side of the pouring cup (222), and the inside of the pouring gate (223), respectively. S3, Gas protection; S3.1, The gas supply system (3) works by sending the mixed gas into the molding cavity through the riser cover (234) and the vent plug (236). After a preset time, the vent plug (236) is removed and the plug ball is quickly reset to the position of the gate (223) to seal the gate (223); S3.2, Gas supply system (3) works by continuously supplying mixed gas into the pouring cup (222) through the pouring cup cover (235) to provide gas protection for the casting process; S4, casting; S4.1, Melting and casting system (1) Pour magnesium alloy molten liquid into the pouring cup (222) until the pouring cup (222) is full of magnesium alloy molten liquid, and then quickly remove the plug ball; S4.2 Continuously pour molten magnesium alloy into the pouring cup (222) until the molten magnesium alloy can be observed through the riser cap (234), then stop pouring and proceed to the feeding stage; S5. The gas supply system (3) stops working, the riser cover (234) and the pouring cup cover (235) are removed, the sand mold inlet and outlet door (232) is opened, the sand mold conveyor line (21) works periodically, and steps S2-S4 are repeated to achieve continuous casting of magnesium alloy castings.

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