A semi-continuous casting system and casting method for ingot casting

Abstract

The present application relates to a semi-continuous casting system and casting method for ingot casting in the field of metal material processing technology, including: a furnace body, the furnace body includes a furnace chamber and a furnace cover; a smelting device, the smelting device is arranged in a closed structure; a vacuum and gas supply device, the vacuum and gas supply device connects the closed structure with the outside and connects the closed structure with a protective gas source; a feeding and stirring device, the feeding and stirring device is mounted above the smelting device, and the feeding and stirring device is used to add at least a part of the raw materials for casting ingots into the smelting device and to stir the melt in the smelting device; a hot top, the hot top is arranged in the closed structure and is suitable for receiving the melt in the smelting device; a crystallization and ingot guide device, the crystallization and ingot guide device is arranged at the bottom outside the furnace chamber and forms a guide channel between the hot top. The present application improves the casting quality of alloy ingots, thereby obtaining high-purity fine-grained homogeneous alloy ingots.

Description

Technical Field

[0001] The present application relates to the technical field of metal material processing, and in particular to a semi-continuous casting system and a casting method for ingot casting. Background Art

[0002] At present, the ingot casting technologies commonly used in industrial production at home and abroad are mainly the following, namely direct water cooling casting technology (DC casting technology), hot top casting technology and gas lubrication (oil lubrication) casting technology; however, these ingot casting technologies are all carried out under the atmosphere, and inevitably there are molten gas absorption, oxidation, burning of alloy components, etc., resulting in casting defects such as pores and inclusions and composition fluctuations in the ingots. Especially for casting ingots with high content of volatile alloy elements, easy to burn, easy to absorb, and easy to oxidize, the casting quality is more difficult to control, and the grains of the obtained ingot structure are relatively coarse, resulting in lower quality of the ingot. Summary of the invention

[0003] In order to improve the casting quality of alloy ingots and obtain fine-grained homogeneous alloy ingots with high purity, the present application provides a semi-continuous casting system and a casting method for ingot casting.

[0004] According to one aspect of the present invention, there is provided a semi-continuous casting system for ingot casting, comprising: a furnace body, the furnace body comprising a furnace chamber and a furnace cover, the furnace chamber and the furnace cover forming a closed structure; a smelting device, the smelting device is arranged in the closed structure and is used to melt the raw materials for casting the ingot to form a melt; a vacuum and gas supply device, the vacuum and gas supply device is arranged outside the closed structure, the vacuum and gas supply device connects the closed structure with the outside world and connects the closed structure with a protective gas source end, and gaseous substances are transported from the closed structure to the outside world or The protective gas flows from the source end to the closed structure in one direction and can be closed at any time; a feeding and stirring device, which is mounted above the smelting device and is used to add at least a part of the raw materials for casting ingots into the smelting device and to stir the melt in the smelting device; a hot top, which is arranged in the closed structure and is suitable for receiving the melt in the smelting device; a crystallization and ingot guiding device, which is installed at the bottom outside the furnace chamber and forms a guide channel with the hot top.

[0005] By using the semi-continuous casting system for ingot casting in the technical solution, the furnace body is evacuated by using a vacuum and gas supply device, the raw materials for casting the ingot are heated under a vacuum environment, the furnace body is filled with protective gas by using a vacuum and gas supply device, the raw materials for casting the ingot are melted under atmosphere protection conditions, and the ingot guiding operation is performed under atmosphere protection conditions, thereby reducing the hydrogen content and slag content in the melt, obtaining a high-purity melt, improving the casting quality of the alloy ingot, and obtaining a high-purity fine-grained homogeneous alloy ingot.

[0006] In addition, the semi-continuous casting system for ingot casting according to the present application may also have the following additional technical features:

[0007] In some embodiments of the present invention, the vacuum and gas supply device includes: a vacuum pump, which connects the closed structure with the outside world to form a one-way flow passage from the closed structure to the outside world; an inflation valve, which connects the protective gas source end with the closed structure to form a one-way flow passage from the protective gas source end to the closed structure.

[0008] In some embodiments of the present invention, the feeding and stirring device includes: a feeding hopper, which is mounted above the smelting device, the feeding hopper connects the closed structure with the outside world and can be closed at any time; a mechanical stirrer, which is mounted on one side of the feeding hopper, and a stirring head is formed at the bottom of the mechanical stirrer, and the stirring head is suitable for stirring the melt in the smelting device.

[0009] In some embodiments of the present invention, the smelting device includes: a crucible, which is arranged on one side of the hot top and has a gap with the bottom wall of the furnace chamber; a heater, which is connected to the outer periphery of the crucible, and the integral structure formed by the heater and the crucible is rotatably connected to the inner wall of the furnace chamber, and the top opening of the crucible can be rotated to the upper part of the hot top at a set angle; and a lifting structure is installed on the furnace cover for the stirring head to rise or fall a set distance.

[0010] In some embodiments of the present invention, the crystallization and ingot guiding device includes: a crystallizer, one end of the crystallizer is connected to the bottom wall of the furnace chamber and communicated with the guide channel; a water tank, the water tank is placed on the outer periphery of the crystallizer, and the inner periphery of the water tank is formed around the crystallizer with multiple water outlets connected to one end of the inner periphery of the crystallizer away from the guide channel, and at least one water inlet is also formed on the water tank; a graphite ring, the graphite ring is arranged on the inner periphery of the crystallizer close to one end of the guide channel; an electromagnetic stirrer, the electromagnetic stirrer is arranged on the outer periphery of the crystallizer and opposite to the graphite ring; an ingot guiding seat, one end of the ingot guiding seat is adapted to one end of the crystallizer away from the guide channel; a traction machine, the traction machine is connected to the end of the ingot guiding seat away from the crystallizer.

[0011] In some embodiments of the present invention, a first sealing ring is provided between the crystallizer and the bottom wall of the furnace chamber, and a second sealing ring is provided between the crystallizer and the ingot guide seat.

[0012] According to another aspect of the present invention, a casting method is provided, which uses the above-mentioned semi-continuous casting system for ingot casting to cast an ingot, and the casting method includes the following steps: configuring raw materials for the ingot, placing at least a portion of the raw materials for casting the ingot in a crucible; evacuating the sealing structure, maintaining the vacuum degree of the sealing structure at a first pressure, and heating the raw materials for casting the ingot in the crucible to a first temperature; evacuating the sealing structure, and when the vacuum degree of the sealing structure drops to a second pressure, filling the sealing structure with a protective gas, maintaining the pressure of the protective gas at a third pressure, melting the raw materials for casting the ingot in the crucible to form a melt and maintaining the temperature at a second temperature; starting a feeding and stirring device to stir the melt in the crucible to a set degree and let it stand for a set time; filling the sealing structure with a protective gas, maintaining the pressure of the protective gas at a fourth pressure, slowly pouring the melt in the crucible into the hot top, and when the melt level in the hot top reaches a set height, starting the crystallization and ingot guiding device to continuously pull out the ingot.

[0013] In addition, the casting method according to the present application may also have the following additional technical features:

[0014] In some embodiments of the present invention, the first pressure is 10-3000Pa, the second pressure is 0.01-10Pa, the third pressure is 1000-10000Pa, and the fourth pressure is 0.10-0.12Mpa; at least for aluminum alloy, steel and copper alloy, the first temperature is 400-550℃, 1200-1400℃ and 800-950℃, respectively, and the second temperature is 680-800℃, 1600-1800℃ and 1100-1300℃, respectively.

[0015] In some embodiments of the present invention, the stirring time of the melt in the crucible by the feeding and stirring device is 3-10 minutes, the stirring speed is 300-800 r / min, and the melt is allowed to stand for 10-40 minutes after stirring.

[0016] In some embodiments of the present invention, the raw materials used for casting ingots are divided into main raw materials and micro raw materials or volatile elements. After the main raw materials are completely melted in the crucible, the micro raw materials or volatile elements are added into the crucible through a feeding and stirring device for melting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0018] Figure 1 It is a schematic diagram of the overall structure of a semi-continuous casting system for ingot casting according to an embodiment of the present application;

[0019] Figure 2 It is a schematic diagram showing the structure of the crystallization and ingot-leading device.

[0020] The reference numerals in the accompanying drawings represent as follows: 1. furnace body; 2. crucible; 3. heater; 4. hot top; 5. melt; 6. flow guide channel; 7. vacuum pump; 8. charging valve; 9. heater power supply; 10. crystallizer; 11. water tank; 12. water outlet; 13. water inlet; 14. graphite ring; 15. electromagnetic stirrer; 16. first sealing ring; 17. ingot guide; 18. traction machine; 19. water inlet pipe; 20. water outlet pipe; 21. groove; 22. insertion part; 23. second sealing ring; 24. hopper; 25. mechanical stirrer. DETAILED DESCRIPTION

[0021] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0022] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0023] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0024] The present application embodiment discloses a semi-continuous casting system for ingot casting. Figure 1 and Figure 2 As shown, the semi-continuous casting system for ingot casting includes a furnace body 1, a smelting device, a hot top 4, a vacuum and gas supply device, and a crystallization and ingot guiding device; wherein, the furnace body 1 includes a furnace chamber and a furnace cover, the furnace chamber and the furnace cover form a closed structure, the smelting device is arranged in the closed structure and is used to melt the raw materials for casting the ingot to form a melt, the smelting device includes a crucible 2 and a heater 3, the crucible 2, the heater 3 and the hot top 4 are placed in the furnace body 1, the heater 3 is arranged on the periphery of the crucible 2, the hot top 4 is suitable for receiving the melt in the smelting device, the vacuum and gas supply device is arranged outside the closed structure, the vacuum and gas supply device connects the closed structure with the outside and connects the closed structure with the protective gas source end, the gaseous substance flows from the closed structure to the outside or from the protective gas source end to the closed structure in one direction and can be closed at any time, the crystallization and ingot guiding device is connected to the outer bottom of the furnace body 1 and forms a guide channel 6 for melt flow between it and the hot top 4.

[0025] By using the semi-continuous casting system for ingot casting in the technical solution, before melting the raw materials for casting the ingot, the furnace body 1 is evacuated by using a vacuum and gas supply device, and when the raw materials for casting the ingot are heated to a certain temperature under a vacuum environment, a protective gas is filled into the furnace body 1 by using a vacuum and gas supply device, and the raw materials for casting the ingot are melted under atmosphere protection conditions, and under atmosphere protection conditions, the melt 5 is pulled out from the crucible 2 through the hot top 4 and the guide channel 6 by using a crystallization and ingot guiding device, and the melt 5 is solidified into a solid ingot according to a specified cross-sectional shape in the crystallization and ingot guiding device, thereby reducing the hydrogen content and slag content in the melt 5 as much as possible, obtaining a high-purity melt 5, and then improving the casting quality of the alloy ingot, and obtaining a high-purity fine-grained homogeneous alloy ingot.

[0026] Specifically, the hot top 4 in this embodiment is placed at the bottom of the furnace body 1 and connected to the inner bottom of the furnace body 1, the heater 3 is fixed on the outer periphery of the crucible 2, and the crucible 2 and the heater 3 are formed as a whole and are located on one side of the hot top 4, the crystallization and ingot introduction device is connected to the outer bottom of the furnace body 1, and the guide channel 6 connects the hot top 4 and the crystallization and ingot introduction device from top to bottom, and the guide channel 6 is a through hole opened on the hot top 4 and the furnace body 1; in other embodiments, the guide channel 6 can also be a heat-resistant pipe connected between the hot top 4 and the crystallization and ingot introduction device.

[0027] In some embodiments of the present invention, Figure 1As shown, the vacuum and gas supply device includes a vacuum pump 7 and a gas charging valve 8, and the vacuum pump 7 and the gas charging valve 8 are respectively formed with an inlet end and an outlet end, and the inlet end of the vacuum pump 7 and the outlet end of the gas charging valve 8 are respectively connected to the furnace body 1. When it is necessary to evacuate the furnace body 1, it is only necessary to close the gas charging valve 8, and then open the vacuum pump 7 to discharge part of the gas in the furnace body 1, so that the pressure in the cavity of the furnace body 1 is less than a standard atmospheric pressure, thereby achieving a vacuum state in the cavity of the furnace body 1; on the contrary, when it is necessary to charge the furnace body 1 with a protective gas, it is only necessary to close the vacuum pump 7, open the gas charging valve 8, and charge the protective gas into the furnace body 1 through the gas charging valve 8.

[0028] Specifically, a heater power supply 9 is arranged at one side of the furnace body 1 in this embodiment, spaced apart from the furnace body 1 . The heater power supply 9 is electrically connected to the heater 3 and the vacuum pump 7 to provide stable electric energy to the heater 3 and the vacuum pump 7 .

[0029] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, the crystallization and ingot-leading device comprises a crystallizer 10 and a water tank 11 disposed on the outer periphery of the crystallizer 10. One end of the crystallizer 10 is connected to the guide channel 6. A plurality of water outlets 12 are formed on the inner periphery of the water tank 11 around the axis of the crystallizer 10. The water outlets 12 are connected to the inner end of the crystallizer 10 away from the furnace body 1. At least one water inlet 13 is formed on the water tank 11. In the process of the melt 5 solidifying into a solid shell in the crystallizer 10, cooling water can be introduced into the water tank 11 through the water inlet 13, and the cooling water is then sprayed on the shell through the water outlet 12, thereby cooling the shell and accelerating the solidification of the liquid alloy solution in the shell.

[0030] In some embodiments of the present invention, Figure 2 As shown, the crystallizer 10 and the water tank 11 are both tubular structures, one end of the crystallizer 10 and the water tank 11 are respectively sealed and connected to the furnace body 1, and the other ends of the water tank 11 and the crystallizer 10 are sealed and connected to each other, a cavity for storing water is formed between the water tank 11 and the crystallizer 10, and the water outlet 12 is arranged on the crystallizer 10. Through the sealing connection process, a cavity is formed between the crystallizer 10 and the water tank 11, so that the cooling water can firstly exchange heat with the periphery of the crystallizer 10 after entering the cavity, thereby improving the efficiency of the melt 5 solidifying into a solid shell in the crystallizer 10.

[0031] Specifically, the water outlet 12 in the present embodiment is a through hole opened on the crystallizer 10, which connects the inner periphery of the crystallizer 10 with the cavity between the water tank 11 and the crystallizer 10; the tubular structure of the crystallizer 10 and the water tank 11 are sealed and connected to the lower surface of the furnace body 1 by welding at one end facing the furnace body 1, and the crystallizer 10 and the water tank 11 are sealed and connected to each other at one end away from the furnace body 1 by welding, thereby forming a cavity with stable structure and reliable sealing in the area enclosed by the crystallizer 10, the water tank 11 and the furnace body 1; compared with opening a water channel in the crystallizer 10 or winding a cooling water pipe on the crystallizer 10, the arrangement method for cooling the cavity is simple to process and ensures a higher cooling efficiency.

[0032] In other embodiments, the tubular crystallizer 10 and the water tank 11 may also be sealedly connected to each other or to the furnace body 1 via flanges. Any structure for sealing the tubular crystallizer 10 and the water tank 11 to each other or to the furnace body 1 falls within the protection scope of the present invention.

[0033] In some embodiments of the present invention, Figure 2 As shown, the water inlet 13 is a water pipe connected to the outside of the water tank 11, and a valve is connected to the water pipe. According to the different types of ingots or the different pulling rates of the ingot shell and the liquid alloy solution therein by the crystallization and ingot drawing devices, the cooling water flow rate can be controlled through the valve to better meet the forming conditions of the ingot.

[0034] In some embodiments of the present invention, Figure 2 As shown, a graphite ring 14 is provided on the inner periphery of the crystallizer 10 near one end of the guide channel 6, and an electromagnetic stirrer 15 is provided on the outer periphery of the crystallizer 10 near one end of the guide channel 6. Through vacuum smelting, electromagnetic stirring of the liquid alloy solution in the billet shell is performed in the semi-continuous casting process to further improve the quality of the alloy ingot, and the electromagnetic stirrer 15 and the graphite ring 14 are arranged on the crystallizer 10 at intervals from the water outlet 12, so that the liquid alloy solution in the billet shell can be stirred and solidified in the crystallizer 10 in sequence, reducing the mutual influence between the two.

[0035] In some embodiments of the present invention, Figure 2 As shown, the electromagnetic stirrer 15 is located in the water tank 11. Under the premise of ensuring that the electromagnetic stirrer 15 is effectively waterproof in the water tank 11, the cooling water can be used for cooling the ingot and heat preservation of the electromagnetic stirrer 15 after entering the water tank 11, thereby improving the space utilization and making the cooling structure simpler and more convenient.

[0036] Specifically, the electromagnetic stirrer 15 in this embodiment is placed in the cavity between the tubular water tank 11 and the crystallizer 10, and is connected to the outer periphery of the crystallizer 10, and a gap is left between the electromagnetic stirrer 15 and the inner periphery of the tubular water tank 11, and the water inlet end 13 is directly opposite to the electromagnetic stirrer 15, so that the cooling water can contact the electromagnetic stirrer 15 more comprehensively.

[0037] In some embodiments of the present invention, Figure 2 As shown, a first sealing ring 16 is provided between the crystallizer 10 and the furnace body 1. When the furnace body 1 is evacuated, the crystallizer 10 is connected with the space inside the furnace body 1 through the guide channel 6. The sealing effect of the first sealing ring 16 reduces the possibility of gas leakage between the crystallizer 10 and the furnace body 1, thereby improving the effect and stability of evacuating the furnace body 1.

[0038] Specifically, in the present embodiment, an annular groove is provided at one end of the crystallizer 10 close to the furnace body 1, and the first sealing ring 16 is embedded in the groove and partially protrudes from the groove. When the crystallizer 10 is tightly connected to the furnace body 1, the first sealing ring 16 is elastically squeezed to form a stable sealing structure between the crystallizer 10 and the furnace body 1.

[0039] In some embodiments of the present invention, Figure 2 As shown, the crystallization and ingot-starting device further includes an ingot-starting seat 17. The end of the inner periphery of the crystallizer 10 away from the furnace body 1 is a trumpet-shaped structure with a large outside and a small inside. One end of the ingot-starting seat 17 is adapted to the trumpet-shaped structure. A traction machine 18 is provided at the end of the ingot-starting seat 17 away from the crystallizer 10. Before the ingot-starting seat 17 starts the ingot-starting operation on the blank shell, the traction machine 18 moves up and down to drive the ingot-starting seat 17 to move up and down, so that the ingot-starting seat 17 is in close contact with the crystallizer 10, thereby facilitating the vacuuming of the furnace body 1 and the filling of the furnace body 1 with protective gas.

[0040] Specifically, in this embodiment, the water outlet 12 on the crystallizer 10 is provided on a trumpet-shaped structure. When the traction machine 18 moves downward and drives the dummy seat 17 and the blank shell to move a certain distance away from the crystallizer 10, a gap is formed between the dummy seat 17 and the crystallizer 10. At this time, the valve on the water pipe of the water tank 11 can be opened to allow cooling water to be sprayed on the blank shell from outside to inside at a certain angle.

[0041] In some embodiments of the present invention, Figure 2 As shown, a cavity is formed in the starter seat 17, and the starter seat 17 is connected with a water inlet pipe 19 and a water outlet pipe 20 which are in communication with the space in the starter seat 17; a valve is connected to the water inlet pipe 19. The circulation of cooling water in the starter seat 17, combined with the cooling water temporarily stored but not flowing in the water tank 11, preliminarily forms a stable structure of the billet shell in the crystallizer 10, especially near the starter seat 17, so as to facilitate the subsequent operation of pulling out the ingot.

[0042] Specifically, in other embodiments, a water pipe that can be freely opened or closed can be connected to the water tank 11, so that before the ingot guiding operation, the ingot guiding seat 17 can cooperate with the water pipe for delivering water to the water tank 11, so that the water tank 11 can also form flowing cooling water during this time period, which is helpful for the formation of the billet shell and improves the protection of the electromagnetic stirrer 15.

[0043] In some embodiments of the present invention, Figure 2 As shown, the end of the crystallizer 10 near the furnace body 1 is a crystallization groove, and the end of the ingot starter seat 17 near the crystallization groove is located in the middle of the ingot starter seat 17 to form a groove 21; specifically, the end of the ingot starter seat 17 near the crystallization groove in this embodiment is integrally formed with an insertion portion 22 for inserting into the crystallization groove, the length of the insertion portion 22 is less than the length of the crystallization groove, and the groove 21 is provided on the insertion portion 22. The arrangement of the groove 21 is not only convenient for the formation of the blank shell, but also convenient for pulling the ingot, and the plug-in cooperation of the insertion portion 22 and the crystallization groove increases the contact area between the crystallizer 10 and the ingot starter seat 17, and improves the sealing between the crystallizer 10 and the ingot starter seat 17.

[0044] In some embodiments of the present invention, Figure 2 As shown, a second sealing ring 23 is provided between the end of the crystallizer 10 away from the furnace body 1 and the ingot starter seat 17. When the furnace body 1 is evacuated, the end of the crystallizer 10 away from the furnace body 1 is connected to the space inside the furnace body 1 through the guide channel 6. The sealing effect of the second sealing ring 23 reduces the possibility of gas leakage between the crystallizer 10 and the ingot starter seat 17, thereby improving the effect and stability of evacuating the furnace body 1.

[0045] Specifically, in the present embodiment, an annular groove is provided at one end of the crystallizer 10 away from the furnace body 1, and the second sealing ring 23 is embedded in the groove and partially protrudes from the groove. When the ingot guide seat 17 is in close contact with the crystallizer 10, the second sealing ring 23 is elastically squeezed to form a stable sealing structure between the ingot guide seat 17 and the crystallizer 10; further, the second sealing ring 23 can be connected to the groove at the bottom of the crystallizer 10 by means of clamping or bonding.

[0046] In some embodiments of the present invention, Figure 1 As shown, a feeding and stirring device is also installed on the furnace body 1, and the feeding and stirring device includes a feeding hopper 24 and a mechanical stirrer 25. The feeding hopper 24 is set above the smelting device, and the feeding hopper 24 connects the closed structure with the outside and can be closed at any time. The feeding hopper 24 is used to add at least a part of the raw materials for casting ingots into the crucible 2. The mechanical stirrer 25 is set on one side of the feeding hopper 24, and a stirring head is formed at the bottom end of the mechanical stirrer 25, and the stirring head is suitable for stirring the melt in the smelting device.

[0047] The passage between the charging hopper 24 and the furnace body 1 can be closed or opened. During the raw material smelting process for casting ingots, micro-alloying raw materials or volatile elements can be placed in the charging hopper 24, and the main alloy raw materials can be placed in the crucible 2 first. When the main alloy raw materials are completely melted in the crucible 2, the charging hopper 24 is opened to add the micro-alloying raw materials or volatile elements into the crucible 2 through the charging hopper 24 for melting to reduce the loss of the micro-alloying raw materials or volatile elements; when all the alloy raw materials are completely melted in the crucible 2, the melt 5 in the crucible 2 is stirred by a mechanical stirrer 25, and then left to stand to make the temperature and composition of the melt 5 uniform.

[0048] In some embodiments of the present invention, Figure 1 As shown, a lifting structure for raising or lowering the stirring head of the mechanical stirrer 25 is installed on the furnace body 1, and the integral structure formed by the heater 3 and the crucible 2 is rotatably connected to the inner wall of the furnace chamber, and the top opening of the crucible 2 can be opened to the upper part of the hot top 4 and rotated to a set angle. When the melt in the crucible 2 needs to be transferred to the hot top 4, it is only necessary to use the lifting structure to lift the stirring head of the mechanical stirrer 25 to the top of the furnace body 1, so that the stirring head of the mechanical stirrer 25 is completely separated from the crucible 2, and then the integral structure formed by the heater 3 and the crucible 2 can be rotated to pour the melt in the crucible 2 into the hot top 4; on the contrary, when the melt in the crucible 2 needs to be stirred, it is only necessary to use the lifting structure to lower the stirring head of the mechanical stirrer 25 into the crucible 2.

[0049] This embodiment also provides a casting method, which uses the above-mentioned semi-continuous casting system for ingot casting to cast an ingot, and the casting method includes the following steps:

[0050] S1. Prepare materials and evacuate the furnace.

[0051] First, alloy raw materials for ingot casting are arranged, and at least a portion of the alloy raw materials are placed in the crucible 2; then, the ingot guide seat 17 is brought into contact with the crystallizer 18 to ensure the sealing between the ingot guide seat 17 and the crystallizer 18, while also ensuring the sealing of the closed structure formed by the furnace chamber and the furnace cover; then, the vacuum pump 7 is used to evacuate the closed structure, and the vacuum degree of the closed structure in the furnace body 1 is maintained at the first pressure.

[0052] S2. Melting of alloy raw materials.

[0053] After completing the preparation work of step (S1), turn on the heater 3 to heat the alloy raw material in the crucible 2 to the first temperature, and then continue to evacuate the furnace body 1. When the vacuum degree of the furnace body 1 drops to the second pressure, turn off the vacuum pump 7 and close the connection between the closed structure and the outside through the vacuum pump. Then open the charging valve 8, and charge the protective gas into the furnace body 1 from the protective gas source end, so that the protective gas pressure in the furnace body 1 is maintained at the third pressure. Thereafter, the alloy raw material in the crucible 2 is melted to form a melt and maintained at the second temperature.

[0054] S3, ingot casting.

[0055] After the alloy raw materials in step (S2) are completely melted, the mechanical stirrer 25 is turned on to stir the melt in the crucible 2 to a set degree and let it stand for a set time after the stirring is completed; then, the protective gas is continuously filled into the furnace body 1 to maintain the protective gas pressure in the furnace body 1 at a fourth pressure. Thereafter, the melt 5 in the crucible 2 is poured into the hot top 4, and the traction machine 18 and the ingot guide seat 17 are used to continuously pull out the initially solidified ingot in the crystallizer 10 to obtain a high-quality fine-grained alloy ingot.

[0056] In some embodiments of the present invention, the first pressure is 10-3000Pa, for example, the first pressure is 20Pa, 50Pa, 200Pa or 1000Pa, etc.; the second pressure is 0.01-10Pa, for example, the second pressure is 0.02Pa, 0.1Pa, 2Pa or 5Pa, etc.; the third pressure is 1000-10000Pa, for example, the third pressure is 2000Pa, 4000Pa, 6000Pa or 8000Pa, etc.; the fourth pressure is 0.10-0.12Mpa, for example, the first pressure is 0.105Mpa, 0.11Mpa, 0.115Mpa or 0.117Mpa, etc.

[0057] In some embodiments of the present invention, at least for aluminum alloys, the first temperature is 400-550°C, such as 420°C, 450°C or 510°C, and the second temperature is 680-800°C, such as 700°C, 740°C or 780°C.

[0058] For steel, the first temperature is 1200-1400°C, such as 1250°C, 1300°C or 1350°C, and the second temperature is 1600-1800°C, such as 1650°C, 1700°C or 1750°C.

[0059] For copper alloys, the first temperature is 800-950°C, such as 850°C, 870°C or 900°C, and the second temperature is 1100-1300°C, such as 1150°C, 1200°C or 1250°C.

[0060] In some embodiments of the present invention, the mechanical stirrer 25 stirs the melt in the crucible 2 for 3-10 min, at a stirring speed of 300-800 r / min, and the melt is allowed to stand for 10-40 min after stirring.

[0061] In some embodiments of the present invention, the alloy raw materials are divided into main alloy raw materials and micro-alloying raw materials or volatile elements. After the main alloy raw materials are completely melted in the crucible, the micro-alloying raw materials or volatile elements are added into the crucible 2 through the feeding hopper 24 for melting.

[0062] In some embodiments of the present invention, the shielding gas is argon.

[0063] In some embodiments of the present invention, the pulling speed of the pulling machine 18 on the starter base 17 and the ingot is 50-400 mm / min.

[0064] The method for casting ingots using the above-mentioned semi-continuous casting system for ingot casting in the present application will be further described below in conjunction with specific embodiments.

[0065] Embodiment 1:

[0066] Casting of 5356 aluminum alloy rods

[0067] (1) First, alloy raw materials for 5356 aluminum alloy casting rods are prepared, and the alloy raw materials are divided into main alloy raw materials and micro-alloying raw materials or volatile elements. The traction machine 18 is raised to make the ingot base 17 seal and contact with the crystallizer 10 through the second sealing ring 23, and the inflation valve 8 is closed to ensure that the furnace body 1 is in a sealed state. Then, the prepared main alloy raw materials of high-purity aluminum, aluminum-manganese master alloy, aluminum-chromium master alloy, and aluminum-titanium master alloy are placed in the crucible 2, and the micro-alloying raw materials or volatile elements of pure magnesium are placed in the charging hopper 24. The vacuum pump 7 is turned on to evacuate the furnace body 1.

[0068] (2) When the vacuum degree in the furnace body 1 drops to 1000Pa, turn on the heater power 9 to heat the main alloy raw material in the crucible 2. When the raw material temperature reaches 500°C and the vacuum degree of the furnace body 1 continues to drop to 0.02Pa, turn off the vacuum pump 7, open the charging valve 8, and charge argon to make the argon pressure in the furnace body 1 reach 5000Pa. The furnace body 1 melts the melt 5 in a closed state. When the main alloy raw material is completely melted, open the feeding hopper 24 to add pure magnesium, continue to heat to 720°C and keep warm, stir the 5356 aluminum melt for 5 minutes at a stirring speed of 500r / min, and then let it stand for 20 minutes to make the temperature and composition of the 5356 aluminum melt uniform.

[0069] (3) After the 5356 aluminum melt has been allowed to stand, argon is continuously introduced into the furnace body 1 until the argon pressure in the furnace body 1 reaches 0.11 MPa. Circulating cooling water is injected into the ingot guide seat 17. The heater 3 and the crucible 2 are rotated to slowly pour the 5356 aluminum melt in the crucible 2 into the hot top 4. When the liquid level in the hot top 4 reaches a certain height, the traction machine 18 is turned on at a traction speed of 200 mm / min. The electromagnetic stirrer 15 is turned on to stir the 5356 aluminum melt in the graphite ring 14 at a stirring current of 40 A and a stirring frequency of 20 Hz. After the traction machine 18 descends to a certain height, the water pipe valve of the water tank 11 is opened to cool the prepared ingot.

[0070] After the melt in the crucible 2 is poured, the crucible 2 returns to its original position; after the melt in the hot top 4 is cast, the electromagnetic stirrer 15 is turned off, the cooling water in the water tank is turned off, and after the ingot is completely separated from the crystallizer 10, the traction machine 18 is turned off and the ingot is taken out to obtain high-quality and high-purity 5356 aluminum alloy cast rods.

[0071] (4) By repeating the above steps, high-quality and high-purity 5356 aluminum alloy cast bars can be continuously obtained.

[0072] Embodiment 2:

[0073] Casting of steel bars

[0074] (1) First, alloy raw materials for steel are prepared and divided into main alloy raw materials and micro-alloying raw materials or volatile elements. The traction machine 18 is raised to make the ingot base 17 seal and contact with the crystallizer 10 through the second sealing ring 23. The inflation valve 8 is closed to ensure that the furnace body 1 is in a sealed state. Then, the main alloy raw materials of steel prepared are placed in the crucible 2, and the micro-alloying raw materials or volatile elements are placed in the charging hopper 24. The vacuum pump 7 is turned on to evacuate the furnace body 1.

[0075] (2) When the vacuum degree in the furnace body 1 drops to 1000Pa, turn on the heater power 9 to heat the main alloy raw material in the crucible 2. When the raw material temperature reaches 1350°C and the vacuum degree of the furnace body 1 continues to drop to 0.02Pa, turn off the vacuum pump 7, open the charging valve 8, and charge argon to make the argon pressure in the furnace body 1 reach 5000Pa. The furnace body 1 melts the melt 5 in a closed state. When the main alloy raw material is completely melted, open the feeding hopper 24 to add micro-alloying raw materials or volatile elements, continue to heat up to 1720°C and keep warm, stir the molten steel for 5 minutes at a stirring speed of 500r / min, and then let it stand for 20 minutes to make the temperature and composition of the molten steel uniform.

[0076] (3) After the molten steel has been allowed to stand, argon is continuously charged into the furnace body 1 until the argon pressure in the furnace body 1 reaches 0.11 MPa. Circulating cooling water is injected into the ingot guide seat 17. The heater 3 and the crucible 2 are rotated to slowly pour the molten steel in the crucible 2 into the hot top 4. When the liquid level in the hot top 4 reaches a certain height, the traction machine 18 is turned on at a traction speed of 70 mm / min. The electromagnetic stirrer 15 is turned on to stir the molten steel in the graphite ring 14 at a stirring current of 40 A and a stirring frequency of 20 Hz. After the traction machine 18 descends to a certain height, the water pipe valve of the water tank 11 is opened to cool the prepared ingot.

[0077] After the melt in the crucible 2 is poured, the crucible 2 returns to its original position; after the melt in the hot top 4 is cast, the electromagnetic stirrer 15 is turned off, the cooling water in the water tank is turned off, and after the ingot is completely separated from the crystallizer 10, the traction machine 18 is turned off and the ingot is taken out to obtain high-quality and high-purity steel cast rods.

[0078] (4) By repeating the above steps, high-quality and high-purity steel cast bars can be continuously obtained.

[0079] Embodiment 3:

[0080] Casting of copper alloy rods

[0081] (1) First, the alloy raw materials of the copper alloy are prepared and divided into the main alloy raw materials and the micro-alloying raw materials or volatile elements. The traction machine 18 is raised to make the ingot base 17 seal and contact with the crystallizer 10 through the second sealing ring 23. The inflation valve 8 is closed to ensure that the furnace body 1 is in a sealed state. Then, the main alloy raw materials of the copper alloy prepared are placed in the crucible 2, and the micro-alloying raw materials or volatile elements are placed in the charging hopper 24. The vacuum pump 7 is turned on to evacuate the furnace body 1.

[0082] (2) When the vacuum degree in the furnace body 1 drops to 1000Pa, turn on the heater power 9 to heat the main alloy raw material in the crucible 2. When the raw material temperature reaches 1350°C and the vacuum degree of the furnace body 1 continues to drop to 0.02Pa, turn off the vacuum pump 7, open the charging valve 8, and charge argon to make the argon pressure in the furnace body 1 reach 5000Pa. The furnace body 1 melts the melt 5 in a closed state. When the main alloy raw material is completely melted, open the feeding hopper 24 to add micro-alloying raw materials or volatile elements, continue to heat to 1720°C and keep warm, stir the copper alloy melt for 5 minutes at a stirring speed of 500r / min, and then let it stand for 20 minutes to make the temperature and composition of the copper alloy melt uniform.

[0083] (3) After the copper alloy melt has been allowed to stand, argon gas is continuously charged into the furnace body 1 until the argon pressure in the furnace body 1 reaches 0.11 MPa. Circulating cooling water is injected into the ingot guide seat 17. The heater 3 and the crucible 2 are rotated to slowly pour the copper alloy melt in the crucible 2 into the hot top 4. When the liquid level in the hot top 4 reaches a certain height, the traction machine 18 is turned on at a traction speed of 130 mm / min. The electromagnetic stirrer 15 is turned on to stir the copper alloy melt in the graphite ring 14 at a stirring current of 40 A and a stirring frequency of 20 Hz. After the traction machine 18 descends to a certain height, the water pipe valve of the water tank 11 is opened to cool the prepared ingot.

[0084] After the melt in the crucible 2 is poured, the crucible 2 returns to its original position; after the melt in the hot top 4 is cast, the electromagnetic stirrer 15 is turned off, the cooling water in the water tank is turned off, and after the ingot is completely separated from the crystallizer 10, the traction machine 18 is turned off and the ingot is taken out to obtain a high-quality and high-purity copper alloy cast rod.

[0085] (4) By repeating the above steps, high-quality and high-purity copper alloy cast rods can be continuously obtained.

[0086] Similarly, the above casting system and casting method are also suitable for aluminum-based composite ingots, magnesium-based composite ingots, copper-based composites, titanium and titanium-based composite ingots.

[0087] The casting system and casting method of the present invention can overcome the casting defects of high hydrogen content and slag content caused by oxidation and slag inclusion in the traditional semi-continuous casting ingot casting process; in addition, through vacuum melting, assisted by electromagnetic stirring of the solidified melt during the semi-continuous casting process, a high-purity fine-grained homogeneous alloy ingot can be obtained.

[0088] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A semi-continuous casting system for ingot casting, characterized in that: include: A furnace body, the furnace body comprising a furnace cavity and a furnace cover, the furnace cavity and the furnace cover forming a closed structure; A smelting device, which is disposed in the closed structure and is used to melt raw materials for casting ingots to form a melt; A vacuum and gas supply device, which is arranged outside the closed structure, connects the closed structure with the outside and connects the closed structure with a protective gas source, and gaseous substances flow from the closed structure to the outside or from the protective gas source to the closed structure in one direction and can be sealed at any time; A feeding and stirring device, which is mounted above the smelting device and is used to add at least a portion of raw materials for casting ingots into the smelting device and to stir the melt in the smelting device; a hot top disposed within the enclosed structure and adapted to receive the melt in the smelting device; A crystallization and ingot-starting device, which is arranged at the outer bottom of the furnace chamber and forms a guide channel between the hot top; The crystallization and ingot-starting device comprises: a crystallizer, one end of which is connected to the bottom wall of the furnace chamber and communicated with the guide channel, and the end of the inner periphery of the crystallizer away from the furnace body is a trumpet-shaped structure with a large outside and a small inside; a water tank, which is placed on the outer periphery of the crystallizer, and the inner periphery of the water tank is formed with a plurality of water outlets connected with one end of the inner periphery of the crystallizer away from the guide channel, and at least one water inlet is formed on the water tank; an ingot-starting seat, one end of which is adapted to one end of the crystallizer away from the guide channel, a cavity is formed in the ingot-starting seat, and the ingot-starting seat is connected with a water inlet pipe and a water outlet pipe connected with the space in the ingot-starting seat; A first sealing ring is arranged between the crystallizer and the bottom wall of the furnace chamber, a second sealing ring is arranged between the crystallizer and the ingot guide seat, and the second sealing ring is located at one end of the crystallizer away from the furnace body.

2. The semi-continuous casting system for ingot casting according to claim 1, characterized in that: The vacuum and gas supply device comprises: A vacuum pump, wherein the vacuum pump connects the closed structure with the outside to form a one-way flow passage from the closed structure to the outside; The inflation valve connects the protective gas source end with the closed structure to form a one-way flow passage from the protective gas source end to the closed structure.

3. The semi-continuous casting system for ingot casting according to claim 1, characterized in that: The feeding and stirring device comprises: A charging hopper, which is mounted above the smelting device and connects the closed structure with the outside world and can be closed at any time; A mechanical stirrer is mounted on one side of the feeding hopper, and a stirring head is formed at the bottom of the mechanical stirrer, and the stirring head is suitable for stirring the melt in the smelting device.

4. The semi-continuous casting system for ingot casting according to claim 3, characterized in that: The smelting device comprises: A crucible, wherein the crucible is arranged on one side of the hot top and is spaced apart from the bottom wall of the furnace chamber; A heater, wherein the heater is connected to the outer periphery of the crucible, and the integral structure formed by the heater and the crucible is rotatably connected to the inner wall of the furnace chamber, and the top opening of the crucible can be rotated to a set angle toward the upper opening of the hot top; and The furnace cover is provided with a lifting structure for the stirring head to rise or fall a set distance.

5. The semi-continuous casting system for ingot casting according to claim 1, characterized in that: The crystallization and ingot starting device also includes: A graphite ring, the graphite ring being arranged on the inner periphery of the crystallizer close to one end of the guide channel; An electromagnetic stirrer, the electromagnetic stirrer is arranged at the periphery of the crystallizer and opposite to the graphite ring; A traction machine is connected to the end of the ingot guide seat away from the crystallizer.

6. A casting method, using the semi-continuous casting system for ingot casting according to any one of claims 1 to 5 to cast an ingot, characterized in that: The following steps are involved: Arranging raw materials for ingot casting, placing at least a portion of the raw materials for casting the ingot in a crucible; The sealing structure is evacuated to maintain a vacuum degree of the sealing structure at a first pressure, and the raw material for casting an ingot in the crucible is heated to a first temperature; The sealing structure is evacuated, and when the vacuum degree of the sealing structure drops to the second pressure, a protective gas is filled into the sealing structure, and the pressure of the protective gas is maintained at a third pressure, and the raw material for casting the ingot in the crucible is melted to form a melt and maintained at the second temperature; Turn on the feeding and stirring device to stir the melt in the crucible to a set degree and let it stand for a set time; Fill the sealing structure with protective gas, maintain the protective gas pressure at the fourth pressure, slowly pour the melt in the crucible into the hot top, and when the melt level in the hot top reaches the set height, start the crystallization and ingot drawing device to continuously pull out the ingot.

7. The casting method according to claim 6, characterized in that: The first pressure is 10-3000Pa, the second pressure is 0.01-10Pa, the third pressure is 1000-10000Pa, and the fourth pressure is 0.10-0.12Mpa; at least for aluminum alloy, steel and copper alloy, the first temperature is 400-550℃, 1200-1400℃ and 800-950℃ respectively, and the second temperature is 680-800℃, 1600-1800℃ and 1100-1300℃ respectively.

8. The casting method according to claim 6, characterized in that: The stirring time of the feeding and stirring device for the melt in the crucible is 3-10 minutes, the stirring speed is 300-800r / min, and the standing time of the melt after stirring is 10-40 minutes.

9. The casting method according to claim 6, characterized in that: The raw materials used for casting ingots are divided into main raw materials and micro raw materials or volatile elements. After the main raw materials are completely melted in the crucible, the micro raw materials or volatile elements are added into the crucible through a feeding and stirring device for melting.

Images