CN106925735A - A kind of device and method for preparing big specification high-quality aluminium alloy cast ingot - Google Patents

Abstract

The invention relates to a device and method for preparing large-scale high-quality aluminum alloy ingots, belonging to the field of metal material processing. The device is mainly composed of a uniform cooler, hot top, oil-gas lubricated crystallizer, induction coil and dummy; the hot top is set above the oil-gas lubricated mold, the induction coil is set outside the oil-gas lubricated mold, and the uniform cooler is set on the oil-gas lubricated mold In the lubricated mold, the dummy is located below the oil-air lubricated mold. The invention cleverly combines the partitioned gas supply crystallizer with a uniform cooler and an electromagnetic stirrer. The effective coupling of the three can realize the forced uniform solidification of the melt under the gas pressure contact state, so that a stable and continuous formation is formed between the melt and the crystallizer. The air film, not only the surface of the ingot is smooth, but also the internal structure is fine and uniform. The large-scale aluminum alloy high-quality ingot prepared by the invention has high production efficiency, is easy to combine with large-scale industrial production, and has broad industrial application prospects in the manufacturing fields of aerospace, rail transit, and ships.

Description

A device and method for preparing large-scale high-quality aluminum alloy ingots

technical field

The invention belongs to the field of metal material processing, and in particular relates to a device and method for preparing large-scale high-quality aluminum alloy ingots.

Background technique

With the improvement of the performance of large-scale complete equipment in the manufacturing industry, it has become an inevitable trend to use more and more large-scale integral structures in aerospace, rail transportation, shipbuilding and other fields, such as large transport aircraft, high-performance fighters and Large-scale overall aluminum materials and high-performance thick plates are widely used in the development of high-speed trains, and the preparation of these materials is inseparable from large-scale and high-quality aluminum alloy ingots. Industrial equipment capability is of great significance.

Semi-continuous casting is the most important method for producing aluminum alloy ingots. However, due to the limitations of the common semi-continuous casting technology, in the process of preparing large-scale aluminum alloy ingots, due to the single cooling method, the ingots solidify from the outside to the inside, which will inevitably cause deep metal melt pockets. At the same time, due to the large size of the ingot, it is difficult to control the uniformity of the temperature field during the solidification process, resulting in uneven solidification shells, and problems such as wrinkles, segregation tumors, and even leaks are prone to occur in the thinner solidification shells; The size is larger and the cooling effect is limited, which will inevitably reduce the continuous casting speed, the nucleation in the melt is less and uneven, and the grains are abnormally coarse. Therefore, the surface quality of large-scale aluminum alloy ingots prepared by traditional semi-continuous casting is poor, the internal structure is coarse and uneven, the composition segregation is serious, and the yield of ingots is low. , material waste is serious.

In order to solve such problems, researchers have conducted a lot of research in order to prepare aluminum alloy ingots with small and uniform internal structure, no segregation, and good surface quality.

Chinese patent CN104550798A proposes an aluminum alloy semi-continuous casting electromagnetic stirring device and method, which adopts the method of combining direct current and permanent magnet, and can design different flow modes of the melt in the mold area according to the size, shape and material composition of the aluminum ingot and flow strength, control the segregation behavior of alloying elements and the growth mode of dendrites, and achieve the purpose of homogenizing and refining the structure. However, this invention adopts a single cooling method that only relies on the sequential solidification of the crystallizer from the outside to the inside, and the problem of uneven temperature during the solidification process of the aluminum alloy melt cannot be solved. Especially for the preparation of large-scale ingots, the stirring effect of this method on the melt Limited, the temperature gradient in the melt is large, and the liquid pocket is very deep, resulting in a slow casting speed, so the effect on improving the internal quality of the ingot is limited.

In terms of improving the surface quality of the ingot, the air film casting method represented by the Airslip technology of the United States and the AirsolVeil technology of Germany, the principle is to form a layer of air film between the crystallizer and the ingot shell to reduce the shell during the solidification process The contact pressure with the inner wall of the crystallizer makes the melt solidify and form in the state of gas contact. Chinese patent CN100418667C improves the oil-gas lubricated crystallizer on this basis, and proposes an overall design of the crystallizer oil, gas, and water structure, reduces the primary cooling through the oil-gas film heat insulation, and uses two rows of water spray holes to improve the secondary water cooling effect , to improve the surface quality of the ingot. However, the existing air film casting method is difficult to prepare high-quality large-scale ingots. If the large-scale ingot is only cooled by the crystallizer, the casting speed is slow, and the initial solidification shell formed by the melt cooling through the crystallizer is very thin and uneven. Using oil film casting technology, oil and gas can easily penetrate the initial solidification shell, resulting in fire escape , leaking and other problems, the production process is difficult to control, so the diameter of the ingot usually cannot exceed 300mm (12 inches), and the air film casting technology cannot solve the problems of fine and uniform solidification structure and composition segregation.

Contents of the invention

The existing air film casting method cannot prepare large-scale aluminum alloy ingots, and there are problems such as poor surface quality of ingots and rough and uneven internal structures. The invention proposes a new device and method for preparing large-scale high-quality aluminum alloy ingots. In the process of air-film casting, uniform cooling in the middle of the crystallizer and electromagnetic stirring coupling melt treatment outside the crystallizer are applied to prepare large-scale high-quality aluminum alloys. When casting alloy ingots, solve the surface quality and internal quality problems of the ingot at the same time.

Its main design idea is: in view of the fact that it is difficult to prepare large-scale (diameter greater than 300mm) aluminum alloy ingots with the existing air film casting method, the crystallizer adopts a partitioned gas supply structure design to reduce the difference in gas supply pressure on the graphite ring and achieve stable Control the gas pressure to ensure that a stable and continuous gas film can be formed between the melt and the mold; apply uniform cooling inside the mold and electromagnetic stirring coupling outside the mold to the alloy melt in the semi-continuous casting process to increase the solidification process of the ingot The cooling dimension in the solidification process strengthens the three-dimensional convection of the melt during the solidification process, improves the uniformity of the temperature field and composition field of the large-volume alloy melt, improves the uniformity of the initial solidification while ensuring the internal quality of the ingot, and increases the initial solidification shell Thickness, preventing the initial solidification shell and oil-gas film from breaking, reducing the contact pressure between the initial solidification shell and the inner wall of the crystallizer, realizing the solidification and forming of the melt under the gas pressure contact state, and preparing large-scale aluminum alloy ingots with excellent internal and external quality.

A new device for preparing large-scale high-quality aluminum alloy ingots, mainly composed of a uniform cooler, a hot top, an oil-gas lubricated crystallizer, an induction coil and a dummy; the hot top is set above the oil-gas lubricated crystallizer, The induction coil is arranged outside the oil-air lubricated mold, the uniform cooler is arranged inside the oil-air lubricated mold, and the dummy is located below the oil-air lubricated mold.

The oil-gas lubricated crystallizer includes a crystallizer body and a graphite ring. The graphite ring is installed above the crystallizer body. The outer wall of the graphite ring is provided with an air groove and an oil groove. The air groove is divided into 3 to 20 sections, and the length of each section of the air groove is 100-500mm, each section is equipped with a separate air intake channel, which is supplied separately and controlled separately; the oil tank is separated from the gas tank, and the oil tank is set on the upper part of the gas tank. The graphite ring is made of porous graphite, and the gas and lubricating oil leak out of the crystallizer through the graphite ring. . The oil-gas lubricated crystallizer adopts a partitioned gas supply structure design, which reduces the difference between the gas volume and air pressure in the single gas supply graphite ring gas tank, and achieves the purpose of stably controlling the gas pressure.

The oil-air lubricated crystallizer adopts a double-row spray hole design. The crystallizer body is provided with upper and lower rows of water spray holes, the angle between the upper row of water spray holes and the wall of the crystallizer is 15-30°, the diameter is 1-5mm, and the angle between the lower row of water spray holes and the wall of the crystallizer is The angle is 0-25° and greater than 0° to ensure that the cooling water can be sprayed onto the ingot without splashing back, and the diameter is 2-8mm. The water volume of the double row of spray holes can be controlled separately, and the diameter of the upper row of spray holes must be less than or equal to the diameter of the lower row of spray holes.

The induction coil is arranged outside the crystallizer. The yoke (iron core) adopts a telescopic design with a variable length and a telescoping range of 0-100mm. The electromagnetic field generated by the electromagnetic induction coil is guided into the melt inside the mold through the yoke. Electromagnetic coils can generate rotating electromagnetic fields, traveling wave electromagnetic fields or composite electromagnetic fields.

The upper part of the uniform cooler is the heat insulating end, the lower part is the cooling end, and the heat insulating end is provided with stirring blades. During the semi-continuous casting process, the uniform cooler extends into the height of the crystallizer through the hot top, and the bottom of the uniform cooler and the crystallizer One or more uniform coolers can be installed in the same level, and the uniform coolers can be rotated at a rotation speed of 0-300r/min.

The insulating end is cylindrical, with an outer diameter of 100-800mm, made of high-temperature-resistant and insulating ceramic material, which has a heat-insulating effect and ensures that the melt in the hot top is not cooled; the cooling end is made of heat-conducting materials, such as graphite and copper , molybdenum, titanium and their composite materials, the cooling end has a cooling effect; the cooling end of the uniform cooler has a spiral shape, and the effect of forcing the melt to flow downward when the uniform cooler rotates; the stirring blade is made of high temperature resistant materials, such as copper , molybdenum, titanium, ceramics and their composite materials, the number of stirring blades is 0-8, the width is 10-100mm, and the thickness is 2-8mm. The stirring blades rotate with the uniform cooler, which has the effect of forcing the melt to flow downward, so that The melt is continuously replenished downwards into the liquid cavity to achieve the effect of dynamic, continuous and uniform cooling; a circulating cooling medium is introduced into the uniform cooler, and the cooling medium reaches the cooling end, and exchanges heat with the melt through the cooling end. The cooling medium is air , Nitrogen, water, oil and other fluids, the cooling medium flow rate is 0-2000L/min.

Based on the above-mentioned device, the present invention proposes a method for preparing large-scale high-quality aluminum alloy ingots. During the semi-continuous casting process, the melt that has been refined and stabilized at 80-100°C above the liquidus line is poured into a hot Inside the top; the air and oil grooves on the outer wall of the graphite ring are fed with air and lubricating oil; the flow of the upper and lower water spray holes is controlled; the alloy melt reaches the upper part of the dummy through the hot top and the crystallizer, and the melt level Raising to the required height, continuous casting starts, the dummy ingot is slowly lowered, and the cooling water flow rate is slowly increased. After the casting process enters a stable state, uniform cooling and electromagnetic stirring are applied, and finally large-scale high-quality aluminum alloy ingots are obtained.

In the semi-continuous casting process, the air flow rate in the air tank is 500-5000mL/min, the oil tank adopts pulsed oil supply, and the oil supply rate is 60-100/s; the flow rate of the upper spray holes is 1-50L /min, the flow rate of the lower spray holes is 20~100L/min; the casting speed is 20~100mm/min. The cooling intensity of the uniform cooling treatment is 500-5000W/(m ² ·k), and the shear rate of the electromagnetic stirring treatment is 10-2000s ^-1 .

The innovation and technical progress of the present invention are mainly reflected in:

1. In the semi-continuous casting process, the present invention cleverly combines the design of the gas supply structure in the partitions of the oil-gas lubricated crystallizer with the uniform cooling in the middle of the crystallizer and the electromagnetic stirring treatment outside the crystallizer. By controlling the cooling effect of the uniform cooler, the structure of the stirring blades and The mutual coupling between the rotating speed and the shear strength of electromagnetic stirring can make the whole melt produce forced uniform cooling and three-dimensional convection. It fundamentally solves the problems of coarse and uneven structure, macro-segregation, cracking and other problems in the preparation of large-scale aluminum alloy ingots by ordinary semi-continuous casting methods, and also greatly increases the uniformity and solidification thickness of the initial solidification shell, effectively reducing the initial solidification. The contact pressure between the shell and the inner wall of the crystallizer realizes the solidification and forming of the melt under the gas pressure contact state, and significantly improves the surface quality of the ingot.

2. The large-scale aluminum alloy oil-gas lubricating cleaner adopts a partitioned gas supply structure design, which can reduce the difference between the gas volume and air pressure in the single gas supply graphite ring gas tank, and can stably control the gas pressure; the pulsed oil supply is used to make the melt A stable and continuous air film can be formed between the mold and the crystallizer to achieve stable lubrication, which solves the technical problem that large-scale aluminum alloy ingots (diameter greater than 300mm) cannot be cast by air film, and the surface of the ingot is smooth.

3. The large-scale cast ingot prepared by the present invention has fine grains, uniform composition, smooth surface, fast casting speed, significantly reduces subsequent homogenization and processing costs, and improves production efficiency and yield. The whole set of methods is simple and feasible, has good implementation effect and can realize industrialized production.

Description of drawings

Figure 1 is a schematic structural view of the device for preparing high-quality large-scale aluminum alloy ingots according to the present invention.

Figure 2 is a schematic diagram of graphite ring partitions.

Fig. 3 is an enlarged view of the partial E area of the crystallizer in Fig. 1 .

Figure 4 is a schematic diagram of a homogeneous cooler.

Figure 5a and Figure 5b are photos of the appearance of the surface of the 7075 aluminum alloy ingot with a diameter of 582 mm and a size of Φ582 mm prepared by ordinary semi-continuous casting and the present invention, respectively.

Figure 6a and Figure 6b are the microstructures of 7075 aluminum alloy ingots with a diameter of Φ582 mm and a size of Φ582 mm prepared by ordinary semi-continuous casting and the present invention, respectively.

Explanation of main reference signs:

1 Homogeneous cooler 2 Hot top

3 Melt 4 Oil-air lubricated crystallizer

5 Yoke 6 Coil

7 Graphite ring 8 Spray hole

9 Ingots 10 Dummy Ingots

11 Oil groove 12 Air groove

13 Upper spray holes 14 Lower spray holes

15 Insulated end 16 Stirring blade

17 cooling end

detailed description

The present invention can be implemented according to the following examples, but is not limited thereto. These examples are only to illustrate the implementation process of the present invention, but not to limit the scope of the present invention in any way. In the following examples, various processes that are not described in detail and methods are conventional methods well known in the art.

As shown in Figure 1, the device of the present invention includes a uniform cooler 1, a hot top 2, a melt 3, an oil-gas lubricated crystallizer 4, a yoke 5, a coil 6, a graphite ring 7, a water spray hole 8, an ingot 9, a lead Ingot 10 etc. The hot top 2 is set above the oil-air lubricated mold 4, the coil 6 and the yoke 5 are set outside the oil-air lubricated mold 4, the uniform cooler 1 is set inside the oil-air lubricated mold 4, and the dummy 10 is located in the oil-air lubricated mold 4 below.

The oil-gas lubricated crystallizer 4 includes a crystallizer body and a graphite ring 7. The graphite ring 7 is installed above the crystallizer body. The outer wall of the graphite ring 7 is provided with an air groove 12 and an oil groove 11. The air groove 12 adopts a segmented design, as shown in Figure 2 As shown, the air tank 12 is divided into 3 to 20 sections, and the length of each section of the air tank 12 is 100 to 500 mm. Each section is provided with a separate air intake channel for separate air supply and separate control; the oil tank 11 is separated from the air tank 12, and the oil tank 11 is set On the upper part of the gas tank 12, the graphite ring 7 is made of porous graphite, and gas and lubricating oil leak out of the crystallizer through the graphite ring 7.

The oil-gas lubricated crystallizer 4 is designed with double rows of water spray holes, as shown in Figure 3; the two rows of water spray holes control the water volume separately, and the angle between the upper row of water spray holes 13 and the inner wall of the oil-gas lubricated crystallizer 4 is 15-30°, and the diameter The angle between the lower row of water spray holes 14 and the wall of the oil-gas lubricated crystallizer 4 is 0 to 25° and greater than 0°, and the diameter is 2 to 8mm. The diameter of the upper row of water spray holes must be less than or equal to the diameter of the lower row of water spray holes diameter.

The yoke 5 adopts a retractable design. The length of the yoke 5 is variable, and the expansion and contraction range is 0-100 mm. The electromagnetic field generated by the electromagnetic induction coil 6 is introduced into the melt inside the crystallizer through the yoke 5 . The electromagnetic coil 6 can generate a rotating electromagnetic field, a traveling wave electromagnetic field or a composite electromagnetic field.

In the semi-continuous casting process, the uniform cooler 1 extends into the height position of the oil-gas lubricated crystallizer 4 through the hot top 2, one or more uniform coolers 1 can be installed, and the uniform cooler 1 can rotate at a rotation speed of 0-300r /min. As shown in Figure 4, the uniform cooler 1 is composed of an upper insulating end 15 and a lower cooling end 17. The insulating end 15 is provided with a stirring blade 16; material; the cooling end 17 is made of thermally conductive materials, such as graphite, copper, molybdenum, titanium and composite materials; the cooling end 17 of the uniform cooler 1 has a spiral shape, and the forced melt is generated downward when the uniform cooler 1 rotates The effect of flow; the number of stirring blades is 0-8, the blade width is 10-100mm, and the blade thickness is 2-8mm. The stirring blade 16 is made of high-temperature resistant materials, such as copper, molybdenum, titanium, ceramics and composite materials, and the blade As the uniform cooler 1 rotates, during use, the melt is driven to gather at the cooling end 17 of the uniform cooler 1, and the circulating cooling medium is passed into the uniform cooler 1, and the cooling medium reaches the cooling end 17, and passes through the cooling end 17 and melt Body heat exchange, the cooling medium is air, nitrogen, water, oil and other fluids, the flow rate of the cooling medium is 0-2000L/min, to achieve continuous dynamic and uniform supercooling of the melt, the melt is cooled by the bottom of the uniform cooler, and continues downward The flow enters the mushy zone of the liquid cavity to realize continuous dynamic and uniform cooling and forced feeding of the melt, and finally prepare a fine-grained homogeneous large-scale ingot.

The method of use is: in the semi-continuous casting process, the whole set of equipment is preheated to 80-200°C, and the melt that has been refined and stabilized at 80-100°C above the liquidus line is poured into the device. During the continuous casting process: air and lubricating oil are fed into the air groove 12 and oil groove 11 on the outer wall of the graphite ring 7, the air flow rate is 500-5000mL/min, the oil supply adopts pulse type, and the oil supply rate is 60-100/s; turn on the electromagnetic Coil 6 with a current of 10-200A controls the flow rate of the upper spray holes 13 to 1-50L/min and the flow rate of the lower spray holes 14 to 20-100L/min; the casting speed is 20-100mm/min.

The alloy melt reaches the upper part of the dummy ingot 10 through the hot top 2 and the crystallizer 4, the liquid level of the melt rises to the required height, the continuous casting starts, the dummy ingot 10 descends slowly, and the flow rate of cooling water increases slowly, until the casting process enters a stable state, Apply uniform cooling and electromagnetic stirring treatment, the cooling intensity of uniform cooling treatment is 500-5000W/(m ² ·k), the shear rate of electromagnetic stirring treatment is 10-2000s ^-1 , until the casting process ends.

Adopting the present invention to prepare round ingots of 7075 aluminum alloys with a specification of Φ582 mm requires smooth surfaces and fine and uniform internal structures. The specific implementation is as follows:

The schematic diagram of the device structure is shown in Figure 1. The oil-gas lubricated crystallizer 4 adopts a partitioned air supply system. The graphite ring 7 is provided with an air groove 12 and an oil groove 11. The air groove 12 is divided into 4 sections, and the length of each section of the air groove 12 is 456mm. Each section is provided with an air inlet channel separately, which is supplied separately and controlled separately; the oil tank 11 is separated from the air tank 12, and the oil tank 11 is arranged on the upper part of the air tank 12, and the graphite ring 7 is made of porous graphite. The angle between the upper row of spray holes 13 and the crystallizer wall is 25°, and the diameter is 2mm. The angle between the bottom row of water spray holes 14 and the crystallizer wall is 10°, and the diameter is 5mm. The water volume of the double row of spray holes can be controlled separately.

The uniform cooler 1 is arranged on the casting platform, the diameter of the cooler is 300mm, the cooler, the hot top and the crystallizer are concentric, and the bottom of the uniform cooler 1 is flush with the bottom of the crystallizer. The insulating end 15 of the uniform cooler 1 is made of high temperature resistant insulating ceramics, with a diameter of 300 mm and a thickness of 10 mm. The lower cooling end 17 has a diameter of 350 mm and is made of graphite. The number of blades is 3 and the width of the blades is 50 mm. The rotation speed of the uniform cooler 1 is 60r/min.

The electromagnetic coil is arranged on the outer periphery of the oil-gas lubricated crystallizer 4, and the electromagnetic coil generates a rotating electromagnetic field to shear the alloy melt, and the length of the magnetic yoke is 50mm.

In the semi-continuous casting process, the melt that has been refined and stabilized at 100 °C above the liquidus line is poured into the hot top. The air groove 12 and the oil groove 11 on the outer wall of the graphite ring 7 are fed with air and lubricating oil, the air flow rate is 1430mL/min, and the pulse type oil supply is adopted, and the oil supply rate is 80/s; the flow rate of the upper spray hole 13 is controlled to be 20L/min. min, the flow rate of the lower spray holes 14 is 30L/min; the casting speed is 65mm/min. The alloy melt reaches the crystallizer through the hot top 2, the liquid level of the melt rises to the required height, the continuous casting starts, the dummy 10 slowly descends, and the cooling water flow rate increases slowly, and when the casting process enters a stable state, uniform cooling and electromagnetic stirring are applied For the treatment, the cooling intensity of the uniform cooling treatment is 1210W/(m ² ·k), and the shear rate of the electromagnetic stirring treatment is 110s ^-1 until the casting process is completed.

By comparing the surface quality and internal structure of the Φ582mm aluminum alloy round ingot prepared by ordinary semi-continuous casting and the present invention, it was found that the ingot produced by ordinary semi-continuous casting had poor surface quality and coarse internal structure, as shown in Figure 5a and Figure 6a It is shown that the surface of the ingot prepared by the present invention is bright, the internal structure is fine and uniform, and the average grain size is 154 μm, as shown in Figure 5b and Figure 6b.

The invention cleverly combines the partitioned gas supply crystallizer with the uniform cooler and the electromagnetic stirrer, the partitioned gas supply crystallizer design can stably control the gas pressure, the uniform cooler increases the cooling dimension during the ingot solidification process, and the electromagnetic stirrer strengthens the solidification process The three-dimensional convection of the melt improves the uniformity of the temperature field and the composition field of the large-volume alloy melt. The effective coupling of the three can realize the forced uniform solidification of the melt under the gas pressure contact state, so that the gap between the melt and the mold It can form a stable and continuous gas film, not only the surface of the ingot is smooth, but also the internal structure is fine and uniform. The large-scale aluminum alloy high-quality ingot prepared by the invention has high production efficiency, is easy to combine with large-scale industrial production, and has broad industrial application prospects in the manufacturing fields of aerospace, rail transit, and ships.

Claims (10)

1. A device for preparing large-scale high-quality aluminum alloy ingots, characterized in that: the device is mainly composed of a uniform cooler, a hot top, an oil-gas lubricated crystallizer, an induction coil and a dummy ingot; the hot top is arranged on Above the oil-air lubricated crystallizer, the induction coil is arranged outside the oil-air lubricated mold, the uniform cooler is arranged inside the oil-air lubricated crystallizer, and the dummy is located below the oil-air lubricated mold. 2. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 1, characterized in that: the oil-gas lubricated crystallizer includes a crystallizer body and a graphite ring, and the graphite ring is installed on the crystallizer body Above, the outer wall of the graphite ring is provided with an air groove and an oil groove, the oil groove is separated from the air groove, and the oil groove is arranged on the upper part of the air groove; the gas groove is divided into 3 to 20 sections, and each section is separately Air supply, individual control. 3. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 2, characterized in that: the length of each air groove is 100-500 mm; the graphite ring is made of porous graphite. 4. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 1, characterized in that: the crystallizer body is provided with upper and lower rows of water spray holes, and the upper row of water spray holes is connected with the crystallizer The angle between the walls is 15-30°, the diameter is 1-5mm, the angle between the lower row of spray holes and the wall of the crystallizer is 0-25° and greater than 0°, and the diameter is 2-8mm; the water volume of the double row of spray holes is controlled separately , the diameter of the upper row of water spray holes is less than or equal to the diameter of the lower row of water spray holes. 5. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 1, characterized in that: the yoke of the induction coil adopts a telescopic design, and the telescopic range is 0-100mm, and the induction coil generates an electromagnetic field The melt is introduced into the mold through the yoke; the induction coil generates a rotating electromagnetic field, a traveling wave electromagnetic field or a composite electromagnetic field. 6. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 1, characterized in that: the upper part of the uniform cooler is an insulating end, and the lower part is a cooling end, and the insulating end is provided with stirring blades; The heat-insulating end is cylindrical and made of high-temperature-resistant heat-insulating ceramic material; the cooling end is made of heat-conducting material; the stirring blade is made of high-temperature-resistant material, and the number of stirring blades is 0-8. 7. The device for preparing large-scale high-quality aluminum alloy ingots according to claim 6, characterized in that: the outer diameter of the heat-insulating end is 100-800mm; the cooling end has a spiral shape and is made of graphite, copper , molybdenum, titanium or composite materials thereof; the stirring blades are made of copper, molybdenum, titanium, ceramics or composite materials thereof, the width of the stirring blades is 10-100mm, and the thickness is 2-8mm. 8. The device for preparing large-scale and high-quality aluminum alloy ingots according to claim 1, characterized in that: the uniform cooler is one or more, set at the height of the crystallizer, and the rotation speed is 0-300r /min; the cooling medium used by the uniform cooler is air, nitrogen, water or oil, and the flow rate of the cooling medium is 0-2000L/min. 9. A method for preparing large-scale high-quality aluminum alloy ingots, comprising the following steps: During the semi-continuous casting process, pouring a melt that has been refined and stabilized at 80-100°C above the liquidus line into a hot top The air and oil grooves on the outer wall of the graphite ring are fed with air and lubricating oil; the flow of the upper and lower water spray holes is controlled; the alloy melt reaches the upper part of the dummy through the hot top and the crystallizer, and the liquid level of the melt rises to The height is required, the continuous casting starts, the dummy ingot is slowly lowered, and the cooling water flow rate is slowly increased. After the casting process enters a stable state, uniform cooling and electromagnetic stirring are applied, and finally large-scale high-quality aluminum alloy ingots are obtained. 10. The method for preparing large-scale high-quality aluminum alloy ingots according to claim 9, characterized in that: the air flow rate in the air tank is 500-5000mL/min, and the oil tank adopts pulsed oil supply, The oil supply rate is 60-100/s; the flow rate of the upper spray hole is 1-50L/min, and the flow rate of the lower spray hole is 20-100L/min; the casting speed is 20-100mm/min; uniform cooling treatment The cooling intensity is 500-5000W/(m ² ·k), and the shear rate of the electromagnetic stirring treatment is 10-2000s ^-1 .