A method for manufacturing 2024 aluminum alloy flat cast ingot for large passenger aircraft

Abstract

The application relates to a manufacturing method of a 2024 aluminum alloy flat ingot for a large passenger plane, and relates to the field of manufacturing methods of 2024 aluminum alloy flat ingots. The application aims to solve the technical problems that defects are prone to be generated in the interior of a large 2024 aluminum alloy flat ingot, the structure is uneven, and the homogenization effect is poor. The method comprises the following steps: 1, weighing; 2, smelting; 3, casting; and 4, grading homogenization treatment. The application adopts a new multi-stage homogenization heat treatment process of high-temperature short-time + medium-temperature long-time, so that non-equilibrium eutectic phases are fully dissolved, and ideal structure preparation is provided for subsequent processing. Finally, a large 2024 aluminum alloy flat ingot with dense structure and uniform performance is successfully prepared. The 2024 aluminum alloy flat ingot prepared by the application has dense structure and uniform performance, and is suitable for being used as main material for manufacturing key load-bearing structural parts of a large passenger plane.

Description

Technical Field

[0001] This invention relates to the field of manufacturing methods for 2024 aluminum alloy flat ingots. Background Technology

[0002] 2024 aluminum alloy, a classic heat-treatable aluminum alloy, is widely used in the aerospace field due to its high strength, excellent fatigue performance, and good machinability. It is particularly important as a primary material for key load-bearing structural components such as the skin and frame of large passenger aircraft, with its core strengthening phases being Al2CuMg and CuAl2 phases. However, these very alloying elements (such as Cu and Mg) that endow 2024 aluminum alloy with high performance also present significant technical challenges in the preparation of its large flat ingots. With the continuous upgrading of passenger aircraft models, the demand for integrated and large-scale structural components is increasing, leading to a corresponding increase in the size of the required aluminum alloy flat ingots. This results in two prominent problems when using traditional manufacturing methods to produce large 2024 flat ingots: First, in terms of ingot forming, large flat ingots are prone to internal defects. 2024 aluminum alloy has a wide solidification temperature range, and alloying elements such as Cu and Mg easily form severe dendritic segregation during solidification, leading to the formation of a large number of low-melting-point eutectic phases at grain boundaries. Second, in terms of microstructure control and performance optimization, traditional homogenization treatments have limited effectiveness. The presence of dendritic segregation and non-equilibrium eutectic phases severely degrades the hot workability of 2024 aluminum alloy, leading to uneven properties in the final product. Homogenization heat treatment is necessary to eliminate these inhomogeneities. However, for large flat ingots with their enormous cross-sections, traditional single-stage or low-temperature, long-duration homogenization processes have inherent limitations.

[0003] In summary, existing technologies lack a manufacturing method that can effectively and synergistically solve the coupled challenges of achieving dense internal forming and controlling uniform microstructure across the entire cross-section of large 2024 aluminum alloy flat ingots. Therefore, developing a novel manufacturing method for 2024 aluminum alloy flat ingots used in large passenger aircraft, through innovative process flow and parameter design, to fundamentally improve the metallurgical quality and microstructure uniformity of the ingots, has become a critical technical problem urgently needing to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of easy defects, uneven structure and poor homogenization effect in large 2024 aluminum alloy flat ingots, and to provide a manufacturing method for 2024 aluminum alloy flat ingots for large passenger aircraft.

[0005] A method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft, specifically comprising the following steps:

[0006] I. Weighing: Based on the elemental mass percentages: Si < 0.15%, Fe < 0.15%, Cu: 3.8%–4.5%, Mn: 0.3%–0.8%, Mg: 1.2%–1.6%, Be: 0.2%, Cr < 0.10%, Zn ≤ 0.25%, Ti < 0.15%, and the balance being Al, weigh Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy as smelting raw materials;

[0007] II. Melting: Al99.99 aluminum ingots and AlMn10 master alloy are placed in a melting furnace for melting. After complete melting, metallic Cu and metallic Zn are uniformly added to the melt. When the melt is completely melted and the temperature is 720℃~750℃, slag is skimmed off. After slag skimming, metallic Mg and AlTi6A master alloy are added sequentially and stirred thoroughly. The stirring operation is stable and the time is ≥15min. After stirring, a layer of powdered flux is uniformly covered. After stirring, samples are taken for chemical composition analysis. After sampling, argon gas is used for refining, and the refining time is ≥30min.

[0008] When the melt temperature reaches 720℃~750℃, the melt is transferred to a holding furnace. When the melt temperature reaches 720℃~745℃, it is stirred, slag is removed, and chemical composition is analyzed. Then, an argon-chlorine mixed gas is introduced, and the melt is refined for 30 minutes before being allowed to stand. During the standing process, the melt temperature is controlled at 700℃~745℃, and the standing time is 30 minutes~300 minutes. After standing, the refined alloy melt is obtained.

[0009] III. Casting: The refined alloy melt from step II is passed through an online degassing device, then through a filtration device, and then through a flow plate. Under the conditions of casting speed of 45~55mm / min, melt casting temperature of 695℃~720℃, casting cooling water flow rate of 70~90t / h, casting water temperature not higher than 28℃, distance of baffle plate from the lower edge of the crystallizer of 280~320mm, and online seeding speed of AlTi5B0.2 wire of 470~490mm / min, the alloy melt is injected into the crystallizer to obtain 2024 aluminum alloy flat ingots through semi-continuous casting.

[0010] Fourth, the 2024 aluminum alloy flat ingots obtained from step three are graded and homogenized, and then sawed and milled to obtain 2024 aluminum alloy flat ingots for large passenger aircraft, thus completing the manufacturing process.

[0011] Further, in step one, according to the elemental mass percentages: Si < 0.06%, Fe < 0.10%, Cu: 4.25%, Mn: 0.55%, Mg: 1.55%, Be: 0.2%, Cr < 0.10%, Zn < 0.10%, Ti < 0.025%, and the balance being Al, Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy are weighed as smelting raw materials.

[0012] Furthermore, in step one, the mass content of Mn in the AlMn10 master alloy is 10%, the mass content of Be in the AlBe3 master alloy is 3%, and the mass content of Ti in the AlTi6 master alloy is 6%.

[0013] Furthermore, the powdered flux mentioned in step two is composed of 40% KCl, 46% MgCl2 and 8% BaCl2 by mass percentage.

[0014] Furthermore, in the argon refining process described in step two, the purity of the argon is 99.999%, with H2 content ≤0.5ppm, O2 content ≤1.5ppm, N2 content ≤4ppm, total CH4+CO+CO2 content ≤1ppm, and water content ≤3ppm.

[0015] Furthermore, in step two, the rotor speed of the device in the argon refining process is 300~400 r / min, and the gas supply pressure is 0.4~0.5 MPa.

[0016] Furthermore, in step three, the aluminum liquid is purified by foam ceramic sheets in the filter of the filtration device. The ceramic sheet size is 584mm×584mm×50mm, and the precision of the foam ceramic sheet is 30ppi+50ppi.

[0017] Furthermore, in step two, the mixing volume ratio of the argon-chlorine mixed gas is 90%~95% argon and 5%~10% chlorine, with the purity of argon ≥99.996% and the purity of chlorine ≥99.999%.

[0018] Furthermore, in step three, the Ti content in the AlTi5B0.2 filaments sown online is 5%, and the B content is 0.2%.

[0019] Furthermore, the graded homogenization process described in step four is divided into three stages: the first and second stages use a high-temperature short-time method, and the third stage uses a high-temperature long-time method.

[0020] In step four, when sawing, the tail end should be sawed for ≥150mm, and the gate end should be sawed for ≥300mm.

[0021] In step four, during milling, the thickness of the ingot after milling is controlled to be 395±10mm, and both surfaces are milled evenly.

[0022] In the 2024 aluminum alloy of this invention, the impurities Si < 0.15%, Fe < 0.15%, Cr < 0.1%, Zn ≤ 0.25%, and other individual impurities < 0.05%. Impurities within this range have no impact on the quality of large 2024 aluminum alloy flat castings.

[0023] Beneficial effects of this invention:

[0024] 1. In the batching process, this invention effectively reduces the tendency of harmful compounds to form in the ingot by precisely controlling the chemical composition. 2. This invention significantly reduces the hydrogen content in the melt by implementing a multi-stage degassing process. 3. In the casting process, this invention effectively reduces internal defects in the ingot by optimizing key process parameters. 4. This invention employs a multi-stage homogenization process, providing ideal microstructure preparation for subsequent processing.

[0025] This invention, through precise composition design and control, strictly limits harmful impurity elements such as Si and Fe to extremely low levels and precisely controls Cu and Mg within the optimal ratio range. This ensures sufficient solute atoms participate in the subsequent formation of the Al2CuMg phase, fundamentally reducing the tendency for the formation of low-melting-point brittle phases and significantly improving the thermoplasticity of the ingot. In the casting process, an innovative stepped variable-parameter degassing and filtration technology is employed to stably control the hydrogen content of the melt below 0.12 mL / 100gAl, effectively eliminating central porosity and macroscopic segregation in large flat ingots. In the subsequent ingot processing, the core of this invention employs a novel multi-stage homogenization heat treatment process of "high temperature short time + medium temperature long time," allowing the non-equilibrium eutectic phase to fully dissolve, providing ideal microstructure preparation for subsequent processing. Ultimately, a large 2024 aluminum alloy flat ingot with a dense microstructure and uniform properties is successfully prepared.

[0026] The 2024 aluminum alloy flat casting ingot prepared by this invention has a dense structure and uniform properties, making it suitable as a main material for manufacturing key load-bearing structural components of large passenger aircraft. Detailed Implementation

[0027] Specific Implementation Method 1: This implementation method describes a manufacturing method for 2024 aluminum alloy flat casting ingots used in large passenger aircraft, specifically carried out according to the following steps:

[0028] I. Weighing: Based on the elemental mass percentages: Si < 0.15%, Fe < 0.15%, Cu: 3.8%–4.5%, Mn: 0.3%–0.8%, Mg: 1.2%–1.6%, Be: 0.2%, Cr < 0.10%, Zn ≤ 0.25%, Ti < 0.15%, and the balance being Al, weigh Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy as smelting raw materials;

[0029] II. Melting: Al99.99 aluminum ingots and AlMn10 master alloy are placed in a melting furnace for melting. After complete melting, metallic Cu and metallic Zn are uniformly added to the melt. When the melt is completely melted and the temperature is 720℃~750℃, slag is skimmed off. After slag skimming, metallic Mg, AlBe3 master alloy, and AlTi6A master alloy are added in sequence and stirred thoroughly. The stirring operation is stable and the time is ≥15min. After stirring, a layer of powdered flux is uniformly covered. After stirring, samples are taken for chemical composition analysis. After sampling, argon gas is used for refining, and the refining time is ≥30min.

[0030] When the melt temperature reaches 720℃~750℃, the melt is transferred to a holding furnace. When the melt temperature reaches 720℃~745℃, it is stirred, slag is removed, and chemical composition is analyzed. Then, an argon-chlorine mixed gas is introduced, and the melt is refined for 30 minutes before being allowed to stand. During the standing process, the melt temperature is controlled at 700℃~745℃, and the standing time is 30 minutes~300 minutes. After standing, the refined alloy melt is obtained.

[0031] III. Casting: The refined alloy melt from step II is passed through an online degassing device, then through a filtration device, and then through a flow plate. Under the conditions of casting speed of 45~55mm / min, melt casting temperature of 695℃~720℃, casting cooling water flow rate of 70~90t / h, casting water temperature not higher than 28℃, distance of baffle plate from the lower edge of the crystallizer of 280~320mm, and online seeding speed of AlTi5B0.2 wire of 470~490mm / min, the alloy melt is injected into the crystallizer to obtain 2024 aluminum alloy flat ingots through semi-continuous casting.

[0032] Fourth, the 2024 aluminum alloy flat ingots obtained from step three are graded and homogenized, and then sawed and milled to obtain 2024 aluminum alloy flat ingots for large passenger aircraft, thus completing the manufacturing process.

[0033] In this embodiment, by strictly controlling the content of impurity elements such as Si, Fe, and Cr, potential factors leading to alloy performance degradation and crack initiation are effectively reduced. Simultaneously, a reasonable ratio of main alloying elements is used, controlling Cu at 3.8%–4.5%, Mg at 1.2%–1.6%, and Mn at 0.3%–0.8%. This combination helps to form a stable alloy phase structure, thereby improving the overall strength and hot workability of the alloy.

[0034] Furthermore, the introduced Ti element can react with Al to form compounds, playing a dual role in refining grain size and improving casting performance, thereby inhibiting crack formation. During the melt treatment stage, stirring at a suitable temperature helps control the alloy's solidification process and promotes the formation of a favorable microstructure. By sampling and analyzing the chemical composition, the melt composition can be monitored and adjusted in a timely manner to ensure it meets specifications, laying a solid foundation for subsequent casting of high-quality ingots.

[0035] Flux covering effectively prevents melt oxidation and gas absorption, reduces impurity content, and improves melt purity. This is crucial for reducing ingot defects and increasing ultrasonic testing pass rate. Subsequent refining processes further remove gases and non-metallic inclusions from the melt. Settling allows residual inclusions and bubbles to rise and dissipate, reducing internal ingot defects.

[0036] Ultimately, by setting precise casting parameters, the solidification and cooling rates of the alloy can be controlled, allowing the ingot to form an excellent microstructure during solidification and reducing thermal stress, thereby significantly reducing the cracking tendency of flat ingots. Among these measures, setting appropriate casting temperature and cooling rate is crucial to preventing cracks caused by drastic temperature changes.

[0037] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: In step one, according to the elemental mass percentages: Si < 0.06%, Fe < 0.10%, Cu: 4.25%, Mn: 0.55%, Mg: 1.55%, Be: 0.2%, Cr < 0.10%, Zn < 0.10%, Ti < 0.025%, and the balance being Al, Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy are weighed as smelting raw materials. Everything else is the same as in Specific Implementation Method One.

[0038] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the mass content of Mn in the AlMn10 master alloy described in step one is 10%, the mass content of Be in the AlBe3 master alloy is 3%, and the mass content of Ti in the AlTi6 master alloy is 6%. Everything else is the same as in Specific Implementation Method One or Two.

[0039] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the powdered flux mentioned in step two is composed of 40% KCl, 46% MgCl2, and 8% BaCl2 by mass percentage. Everything else is the same as in Specific Implementation Methods One to Three.

[0040] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in the argon refining process described in step two, the purity of the argon is 99.999%, with H2 content ≤0.5ppm, O2 content ≤1.5ppm, N2 content ≤4ppm, the total content of CH4+CO+CO2 ≤1ppm, and water content ≤3ppm. Everything else is the same as in Specific Implementation Methods One to Four.

[0041] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the rotor speed of the device in the argon refining process described in step two is 300~400 r / min, and the gas supply pressure is 0.4~0.5 MPa. Everything else is the same as in Specific Implementation Methods One to Five.

[0042] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that: in step three, the filter in the filtration device uses foam ceramic sheets to purify the molten aluminum. The ceramic sheet size is 584mm × 584mm × 50mm, and the precision of the foam ceramic sheet is 30ppi + 50ppi. Everything else is the same as in Specific Implementation Methods One through Six.

[0043] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: the mixing volume ratio of the argon-chlorine mixed gas in step two is 90%~95% argon and 5%~10% chlorine, with the purity of argon ≥99.996% and the purity of chlorine ≥99.999%. Everything else is the same as in Specific Implementation Methods One to Seven.

[0044] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step three, the Ti mass content of the AlTi5B0.2 filaments sown online is 5%, and the B mass content is 0.2%. Everything else is the same as in Specific Implementation Methods One to Eight.

[0045] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the graded homogenization process described in step 4 is divided into three stages. The first and second stages are processed using a high-temperature short-time method, while the third stage is processed using a high-temperature long-time method.

[0046] In step four, when sawing, the tail end should be sawed for ≥150mm, and the gate end should be sawed for ≥300mm.

[0047] In step four, during milling, the thickness of the ingot after milling is controlled to be 395±10mm, and both surfaces are milled evenly. Other aspects are the same as in any of the specific implementation methods one through nine.

[0048] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0049] Example:

[0050] A method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft is implemented according to the following steps:

[0051] I. Weighing: Weigh Al99.99 aluminum ingot, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy and AlMn10 master alloy as smelting raw materials according to the following mass percentages: Si≤0.06%, Fe≤0.10%, Cu: 4.25%, Mn: 0.53%, Mg: 1.4%, Ti: 0.02%, Be: 0.2%, Cr≤0.05%, Ni≤0.05%, Zn≤0.25%, and the balance being Al.

[0052] II. Melting: Al99.99 aluminum ingots and AlMn10 master alloy are placed in a melting furnace for melting. After complete melting, metallic Cu and metallic Zn are uniformly added to the melt. When the melt is completely melted and the temperature is 725℃, slag is skimmed off. After slag skimming, metallic Mg, AlBe3 master alloy, and AlTi6A master alloy are added in sequence and stirred thoroughly. The stirring operation is stable and the stirring is carried out for about 15 minutes. After stirring, a layer of powdered flux is uniformly covered. After stirring, samples are taken for chemical composition analysis. The samples are then refined using argon gas.

[0053] The refined melt was transferred to a holding furnace, stirred, slag removed, and its chemical composition tested and adjusted. During sampling, the melting temperature was 722℃. After adjustment, an argon-chlorine mixed gas was introduced, and the melt was refined for 30 minutes before being allowed to stand. During the standing process, the melt temperature was 735℃, and the standing time was 50 minutes. After standing, the refined alloy melt was obtained.

[0054] III. Casting: The refined alloy melt is passed through an online degassing device, then through a filtration device, and then through a flow plate. Under the conditions of casting speed of 50 mm / min, melt casting temperature of 705℃, casting cooling water flow rate of 80 t / h, casting water temperature of 21.7℃, water baffle distance from the lower edge of the crystallizer of 300 mm, and online seeding speed of AlTi5B0.2 wire of 480 mm / min, the alloy melt is injected into the crystallizer to obtain 2024 aluminum alloy flat ingots through semi-continuous casting.

[0055] IV. After casting is completed, a graded homogenization treatment is carried out. The first stage is a furnace gas temperature of 530℃, a heating time of 300 min, and a holding time of 140 min. The second stage is a furnace gas temperature of 490℃, a heating time of 60 min, and a holding time of 360 min. The third stage is a furnace gas temperature of 490℃ and a holding time of 1140 min. After the homogenization treatment is completed, the ingot is sawed and milled.

[0056] The 2024 aluminum alloy flat casting ingot prepared in this embodiment has qualified chemical composition and no defects such as cracks or slag inclusions on the surface. It is suitable as a main material for manufacturing key load-bearing structural components such as the skin and frame of large passenger aircraft.

Claims

1. A method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft, characterized in that... This method is specifically carried out in the following steps: I. Weighing: Based on the elemental mass percentages: Si < 0.15%, Fe < 0.15%, Cu: 3.8%–4.5%, Mn: 0.3%–0.8%, Mg: 1.2%–1.6%, Be: 0.2%, Cr < 0.10%, Zn ≤ 0.25%, Ti < 0.15%, and the balance being Al, weigh Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy as smelting raw materials; II. Melting: Al99.99 aluminum ingots and AlMn10 master alloy are placed in a melting furnace for melting. After complete melting, metallic Cu and metallic Zn are uniformly added to the melt. When the melt is completely melted and the temperature is 720℃~750℃, slag is skimmed off. After slag skimming, metallic Mg, AlBe3 master alloy, and AlTi6A master alloy are added in sequence and stirred thoroughly. The stirring operation is stable and the time is ≥15min. After stirring, a layer of powdered flux is uniformly covered. After stirring, samples are taken for chemical composition analysis. After sampling, argon gas is used for refining, and the refining time is ≥30min. When the melt temperature reaches 720℃~750℃, the melt is transferred to a holding furnace. When the melt temperature reaches 720℃~745℃, it is stirred, slag is removed, and chemical composition is analyzed. Then, an argon-chlorine mixed gas is introduced, and the melt is refined for 30 minutes before being allowed to stand. During the standing process, the melt temperature is controlled at 700℃~745℃, and the standing time is 30 minutes~300 minutes. After standing, the refined alloy melt is obtained. III. Casting: The refined alloy melt from step II is passed through an online degassing device, then through a filtration device, and then through a flow plate. Under the conditions of casting speed of 45~55mm / min, melt casting temperature of 695℃~720℃, casting cooling water flow rate of 70~90t / h, casting water temperature not higher than 28℃, distance of baffle plate from the lower edge of the crystallizer of 280~320mm, and online seeding speed of AlTi5B0.2 wire of 470~490mm / min, the alloy melt is injected into the crystallizer to obtain 2024 aluminum alloy flat ingots through semi-continuous casting. Fourth, the 2024 aluminum alloy flat ingots obtained from step three are graded and homogenized, and then sawed and milled to obtain 2024 aluminum alloy flat ingots for large passenger aircraft, thus completing the manufacturing process.

2. The manufacturing method of a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... Step 1: Weigh out Al99.99 aluminum ingots, metallic Cu, metallic Mg, metallic Zn, AlTi6A master alloy, AlBe3 master alloy, and AlMn10 master alloy as smelting raw materials according to the following element mass percentages: Si < 0.06%, Fe < 0.10%, Cu: 4.25%, Mn: 0.55%, Mg: 1.55%, Be: 0.2%, Cr < 0.10%, Zn < 0.10%, Ti < 0.025%, and the balance being Al.

3. The manufacturing method of a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... In step one, the mass content of Mn in the AlMn10 master alloy is 10%, the mass content of Be in the AlBe3 master alloy is 3%, and the mass content of Ti in the AlTi6 master alloy is 6%.

4. The manufacturing method of a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... The powdered flux mentioned in step two consists of 40% KCl, 46% MgCl2 and 8% BaCl2 by mass percentage.

5. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... In the argon refining process described in step two, the purity of argon is 99.999%, with H2 content ≤0.5ppm, O2 content ≤1.5ppm, N2 content ≤4ppm, total CH4+CO+CO2 content ≤1ppm, and water content ≤3ppm.

6. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... In step two, the rotor speed of the argon refining process is 300-400 r / min, and the gas supply pressure is 0.4-0.5 MPa.

7. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... In step three, the aluminum liquid is purified by foam ceramic sheets in the filter of the filtration device. The ceramic sheet size is 584mm×584mm×50mm, and the precision of the foam ceramic sheet is 30ppi+50ppi.

8. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... The mixing volume ratio of the argon-chlorine mixed gas in step two is 90%~95% argon and 5%~10% chlorine, with the purity of argon ≥99.996% and the purity of chlorine ≥99.999%.

9. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... Step 3: The AlTi5B0.2 fiber, which is seeded online, contains 5% Ti and 0.2% B by mass.

10. The method for manufacturing a 2024 aluminum alloy flat casting ingot for large passenger aircraft according to claim 1, characterized in that... The graded homogenization process described in step four is divided into three stages. The first and second stages use a high-temperature short-time method, while the third stage uses a high-temperature long-time method. In step four, when sawing, the tail end should be sawed for ≥150mm, and the gate end should be sawed for ≥300mm. In step four, during milling, the thickness of the ingot after milling is controlled to be 395±10mm, and both surfaces are milled evenly.