A method for preparing a rare earth-containing aluminum alloy flat ingot for aviation

Abstract

A method for preparing a rare earth aluminum alloy flat ingot for aviation use. The present invention specifically relates to a method for preparing a rare earth aluminum alloy flat ingot for aviation use. The present invention aims to solve the problems that the performance of the existing ingots after rolling is unqualified, and the ingots have low yield rate due to surface crack defects and low flaw detection pass rate. Method: 1. Weigh the smelting raw materials; 2. Smelt the smelting raw materials in sequence; 3. Put the alloy melt into a holding furnace for casting to obtain an aluminum alloy flat ingot. The present invention adopts the existing melting and casting process and combines the scientific proportion of raw materials and the fine operation in the production process to reduce the generation of ingot crack defects, and obtain a relatively pure melt, so that the comprehensive yield rate of the ingot reaches 87%, and the tensile strength of the plate after the ingot is rolled is increased by about 8% on the basis of the original high zinc alloy, and the yield strength is increased by about 12%.

Description

Technical Field

[0001] The invention specifically relates to a method for preparing a rare earth-containing aluminum alloy flat ingot for aviation. Background Art

[0002] In the field of aerospace, the requirements for material properties are extremely stringent, and aluminum alloys occupy an important position in it due to their unique performance advantages. Super-hard aluminum of the Al-Zn-Mg-Cu system has many excellent properties. Its high strength characteristics enable it to withstand the various complex stresses faced by aircraft during flight. Whether it is the aerodynamic load during flight or the gravity load of the aircraft structure itself, the material is required to have sufficient strength to ensure the integrity and safety of the aircraft structure. Good fracture toughness ensures that the material will not suddenly fracture brittlely in the case of local stress concentration or accidental impact, but can absorb energy in a relatively safe way and maintain a certain structural stability. Stress corrosion resistance and spalling resistance are crucial for aircraft parts that are in complex environments (such as humidity, high salinity, etc.) for a long time. They can effectively prevent the decrease in structural strength and potential failures caused by corrosion or spalling of surface materials. In addition, its advantages such as good quenching sensitivity and compressive stress resistance also make it adaptable and reliable in the heat treatment process and actual use scenarios of aviation manufacturing. Therefore, its thick plates are widely used in key parts such as wing upper skin parts.

[0003] However, in the actual production and application process, the alloy faces a series of serious problems. From the perspective of chemical composition and phase composition, its inherent characteristics result in the strength of the billet being unable to reach the high standard strength value required for aircraft skin after being rolled into a plate. This makes it difficult for the plates made of this alloy to directly meet the key performance indicators of aviation structural parts, limiting its effective application in the aviation field.

[0004] The problem is more prominent in the casting process. The alloy shows a great tendency to crack, which is mainly due to the solidification characteristics determined by its special chemical composition and phase composition. The range of its melting and casting process parameters is extremely narrow, which means that in the casting process, the adjustable space of process parameters such as temperature, cooling rate, and alloy composition fine-tuning is extremely small, and any slight deviation may cause cracks. In actual production, cracked scrap often occurs, which not only causes a large amount of raw material waste, but also seriously affects production efficiency and cost control. At the same time, it is difficult to control the purity of the melt, and impurity elements and inclusions are easily mixed into the melt, which not only affects the uniformity and stability of the alloy, but also further aggravates the tendency to crack and reduces the pass rate of flaw detection. At present, the yield rate of its ingot casting is only 50%. Such a low yield rate greatly increases the production cost and limits the large-scale application and promotion of the alloy in the aviation industry.

[0005] In summary, in order to overcome the problems in the prior art of unqualified plate performance after rolling of the alloy ingot and low ingot yield due to surface crack defects and low flaw detection pass rate, it is urgently necessary to develop a new method for preparing rare earth aluminum alloy flat ingots for aviation. Summary of the invention

[0006] The present invention aims to solve the problems that the plate performance after the existing ingot rolling is unqualified, the ingot has a low finished product rate due to surface crack defects and low flaw detection pass rate, and provides a method for preparing a rare earth aluminum alloy flat ingot for aviation.

[0007] A method for preparing a rare earth-containing aluminum alloy flat ingot for aviation is completed by the following steps:

[0008] 1. Weighing: According to the mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.2%-1.5%, Mn: 0.1-0.4%, Mg: 1.5%-3.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 4.5%-7.0%, Zr: 0.11%-0.20%, Sc: 0.10-0.35%, Ti: 0.02-0.10% and the balance is Al, weigh Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy as smelting raw materials;

[0009] 2. Melting: first put Al99.70 aluminum ingot into the melting furnace, then add AlMn10 master alloy, AlZr3 master alloy, AlTi6 master alloy in turn, add AlSc2 master alloy when the melt temperature reaches 800℃ and stir for no less than 15min, then heat to 800℃ again, keep warm at 800℃, stir once every 30min, stir 3 times in total, then add metal Cu, metal Mg, metal Zn into the melting furnace, then stir at 780℃ for 15min, take samples and analyze chemical composition, after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0010] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 50 mm / min, a melt casting temperature of 720°C, a casting cooling water flow of 40 t / h, a casting water temperature of 25°C, and an online seeding speed of 370 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain a flat ingot of rare earth-containing aluminum alloy for aviation use.

[0011] Beneficial effects of the present invention:

[0012] The present invention selects different addition times according to the characteristics of different alloys, thereby solving the problem of sufficient alloying of various elements; by adding the rare earth element Sc, the performance after rolling can be improved; by introducing argon-chlorine mixed gas for refining, alkali and alkaline earth metals such as Na and Ca in the melt can be effectively reduced; the melt flows into an online degassing device, which can effectively remove H2 in the melt; and flows into a filtering device, which can effectively remove slag; the yield rate of ingots obtained according to the above method is improved to 87%, solving the problem of low yield rate of ingots prepared by the existing method, and the tensile strength of the plate after rolling is increased by about 8%, and the yield strength is increased by about 12%. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any combination of the specific implementation modes.

[0014] Specific implementation method 1: In this implementation method, a method for preparing a rare earth aluminum alloy flat ingot for aviation is completed by the following steps:

[0015] 1. Weighing: According to the mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.2%-1.5%, Mn: 0.1-0.4%, Mg: 1.5%-3.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 4.5%-7.0%, Zr: 0.11%-0.20%, Sc: 0.10-0.35%, Ti: 0.02-0.10% and the balance is Al, weigh Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy as smelting raw materials;

[0016] 2. Melting: first put Al99.70 aluminum ingot into the melting furnace, then add AlMn10 master alloy, AlZr3 master alloy, AlTi6 master alloy in turn, add AlSc2 master alloy when the melt temperature reaches 800℃ and stir for no less than 15min, then heat to 800℃ again, keep warm at 800℃, stir once every 30min, stir 3 times in total, then add metal Cu, metal Mg, metal Zn into the melting furnace, then stir at 780℃ for 15min, take samples and analyze chemical composition, after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0017] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 50 mm / min, a melt casting temperature of 720°C, a casting cooling water flow of 40 t / h, a casting water temperature of 25°C, and an online seeding speed of 370 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain a flat ingot of rare earth-containing aluminum alloy for aviation use.

[0018] In this embodiment, Sc is a light rare earth element of the transition group, which is often added to Al alloys as a trace alloying element, and can significantly improve the performance of the alloy. The tensile strength and yield strength of the aluminum alloy are improved because during the solidification process of the aluminum alloy, the primary Al3Sc particles precipitated by the peritectic reaction between Al and Sc can serve as nucleation points for the aluminum alloy grains, and can refine the grains of the aluminum alloy; during the heat treatment process of the aluminum alloy, the Sc atoms dissolved in the matrix and the Al atoms form dispersed Al3Sc particles that are coherent with the matrix. The Al3Sc phase has a good ability to resist coarsening, and can improve the mechanical properties, recrystallization temperature, creep resistance, etc. of the aluminum alloy.

[0019] Adding a small amount of Ti can significantly refine the alloy grains and reduce the crack tendency of the alloy. Si, Fe, Cr, and Ni are all impurity elements, and the lower their content is in actual production, the better.

[0020] This embodiment improves the purity of the melt by performing precise control during the casting process, optimizes the melting and casting process parameters to reduce the crack tendency of the flat ingot and solve the surface crack defects of the ingot, thereby improving the ingot flaw detection yield rate and the yield rate of the entire ingot. At the same time, rare earth elements are added to the alloy to improve its organizational structure and performance, and ultimately achieve the improvement of the performance of the plate after rolling to meet the urgent demand of the aviation industry for high-performance aluminum alloy materials.

[0021] In the batching stage, the present embodiment accurately weighs various raw materials according to specific mass percentages. The content of impurity elements such as Si and Fe is strictly controlled (Si is less than 0.18%, Fe is less than 0.18%), reducing factors that may cause alloy performance degradation and cracks. At the same time, the proportions of the main alloying elements Cu (0.2%-1.5%), Mg (1.5%-3.0%), Zn (4.5%-7.0%), etc. are reasonably configured. The reasonable combination of these elements helps to form a stable alloy phase structure and improve the strength and toughness of the alloy.

[0022] Rare earth element addition: rare earth elements and trace elements such as Zr (0.11%-0.20%), Sc (0.10-0.35%), and Ti (0.02-0.10%) are added. Zr and Sc can refine the grain structure of the alloy and make the alloy's structure more uniform. The refined grains can effectively hinder dislocation movement, thereby improving the strength and toughness of the alloy. The Ti element can form a compound with Al as a heterogeneous nucleation core, further refine the grains, and improve the casting properties of the alloy and reduce the generation of cracks.

[0023] Sequential feeding and stirring: A specific smelting sequence is used. First, Al99.70 aluminum ingots are put in, and then AlMn10 master alloy, AlZr3 master alloy, and AlTi6 master alloy are added in sequence. When the melt temperature reaches 800°C, AlSc2 master alloy is added for stirring, and the stirring time is not less than 15 minutes. This sequential feeding and sufficient stirring method can ensure that various alloy elements are evenly dissolved in the melt to avoid local component segregation. Uniform component distribution helps to form a stable alloy phase structure and reduce performance differences and crack tendencies caused by uneven composition. After stirring, the temperature is raised to 800°C again and kept warm. Stir once every 30 minutes, and stir 3 times in total, which further ensures the uniformity of the melt.

[0024] Temperature and stirring control: After adding metal Cu, metal Mg, and metal Zn, stir at 780℃ for 15 minutes. This process can make these main alloy elements better integrated into the melt, and stirring at the appropriate temperature can control the solidification process of the alloy, which is conducive to the formation of a good organizational morphology. Sampling and analyzing the chemical composition can timely discover the component deviation and make adjustments to ensure that the melt composition meets the requirements, thus laying the foundation for the subsequent casting of high-quality ingots. Covering flux can prevent melt oxidation and air absorption, reduce the impurity content in the melt, and improve the purity of the melt, which is very important for reducing defects in ingots and improving the pass rate of flaw detection.

[0025] Refining and standing: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and then refining is carried out for 30 minutes by introducing an argon-chlorine mixed gas, and then standing for 60 minutes. The refining process can effectively remove the gas and inclusions in the melt, further improving the purity of the melt. Standing can make the inclusions and bubbles in the melt float up, reducing defects in the ingot.

[0026] Casting parameter control: After further purifying the melt through the online degassing device and the filtering device, the melt is injected into the crystallizer for semi-continuous casting under the conditions of specific casting speed (50mm / min), melt casting temperature (720℃), casting cooling water flow (40t / h), casting water temperature (25℃), and online seeding AlTi5B1 wire speed (370mm / min). These precise casting parameters can control the solidification rate and cooling rate of the alloy, so that the ingot forms a good organizational structure during the solidification process, reduce the generation of thermal stress, and thus reduce the crack tendency of the flat ingot. Appropriate casting temperature and cooling rate can avoid cracks caused by rapid temperature changes, and online seeding of AlTi5B1 wire can further refine the grains, improve the quality of the ingot, solve the surface crack defects of the ingot, and thus improve the yield rate of the entire ingot.

[0027] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that: in step 1, according to the mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.32%, Mn: 0.3%, Mg: 2.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 5.4%, Zr: 0.13%, Sc: 0.14%, Ti: 0.03% and the balance is Al, Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy are weighed as smelting raw materials. The rest is the same as specific embodiment 1.

[0028] Specific embodiment 3: This embodiment is different from specific embodiment 2 in that the content of Mn in the AlMn10 master alloy in step 1 is 10%, the content of Zr in the AlZr3 master alloy is 3%, the content of Sc in the AlSc2 master alloy is 2%, and the content of Ti in the AlTi6 master alloy is 6%. Others are the same as specific embodiment 2.

[0029] Specific embodiment 4: This embodiment differs from specific embodiment 1 in that: the flux in step 2 is composed of 40% KCl, 46% MgCl2, 8% BaCl2, and 6% NaCl+CaCl2 by mass percentage; the amount of flux added is 2 kg / ton of melt. Others are the same as specific embodiment 1.

[0030] Specific implementation method 5: This implementation method is different from specific implementation method 1 in that the argon-chlorine mixed gas in step 3 is composed of 94% argon and 6% chlorine by volume, and the purity of argon and chlorine is 99.999%. Other aspects are the same as specific implementation method 1.

[0031] Specific embodiment 6: This embodiment is different from the specific embodiment 5 in that the introduction rate of the argon-chlorine mixed gas in step 3 is 0.30-0.35 m 3 / min. The rest is the same as the fifth embodiment.

[0032] Specific implementation method 7: This implementation method is different from specific implementation method 1 in that: the degassing device in step 3 is a dual-rotor online degassing device, and the gas in the degassing device is Ar gas with a purity of 99.996%; the filtering device uses a double-stage ceramic filter for filtering, and the double-stage ceramic filter is an imported 30ppi+50ppi. The rest is the same as specific implementation method 1.

[0033] Specific embodiment 8: This embodiment differs from specific embodiment 1 in that the Ti content of the online seeded AlTi5B1 wire in step 3 is 5% and the B content is 1%. The rest is the same as specific embodiment 1.

[0034] Specific embodiment 9: This embodiment differs from specific embodiment 1 in that the shape of the melt injected into the crystallizer in step 3 is a rectangle of 420 mm×1620 mm. The rest is the same as specific embodiment 1.

[0035] Specific embodiment 10: This embodiment differs from specific embodiment 1 in that the size of the rare earth-containing aluminum alloy flat ingot for aviation in step 3 is 420 mm×1620 mm×5000 mm to 6000 mm. Other aspects are the same as those of specific embodiment 1.

[0036] The following examples are used to verify the beneficial effects of the present invention:

[0037] Embodiment 1: A method for preparing a rare earth aluminum alloy flat ingot for aviation is completed by the following steps:

[0038] 1. Weighing: According to the mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.32%, Mn: 0.3%, Mg: 2.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 5.4%, Zr: 0.13%, Sc: 0.14%, Ti: 0.03% and the balance is Al, weigh Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy as smelting raw materials;

[0039] 2. Melting: first put Al99.70 aluminum ingot into the melting furnace, then add AlMn10 master alloy, AlZr3 master alloy, AlTi6 master alloy in turn, add AlSc2 master alloy when the melt temperature reaches 800℃ and stir for no less than 15min, then heat to 800℃ again, keep warm at 800℃, stir once every 30min, stir 3 times in total, then add metal Cu, metal Mg, metal Zn into the melting furnace, then stir at 780℃ for 15min, take samples and analyze chemical composition, after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0040] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 50 mm / min, a melt casting temperature of 720°C, a casting cooling water flow of 40 t / h, a casting water temperature of 25°C, and an online seeding speed of 370 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain a flat ingot of rare earth-containing aluminum alloy for aviation use.

[0041] The rare earth-containing aluminum alloy flat ingot for aviation obtained in this embodiment has qualified chemical composition, no surface defects such as cracks and slag inclusions, and a yield rate of 87%. After rolling, the tensile strength of the plate is increased by 8%, and the yield strength is increased by 12%.

[0042] Embodiment 2: A method for preparing a rare earth aluminum alloy flat ingot for aviation use is completed by the following steps:

[0043] 1. Weighing: According to the ratio of mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.30%, Mn: 0.31%, Mg: 2.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 5.5%, Zr: 0.13%, Sc: 0.14%, Ti: 0.03% and the balance of Al, weigh Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy as smelting raw materials;

[0044] 2. Melting: first put Al99.70 aluminum ingot into the melting furnace, then add AlMn10 master alloy, AlZr3 master alloy, AlTi6 master alloy in turn, add AlSc2 master alloy when the melt temperature reaches 800℃ and stir for no less than 15min, then heat to 800℃ again, keep warm at 800℃, stir once every 30min, stir 3 times in total, then add metal Cu, metal Mg, metal Zn into the melting furnace, then stir at 780℃ for 15min, take samples and analyze chemical composition, after the chemical composition is qualified, cover with flux to obtain alloy melt;

[0045] 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 50 mm / min, a melt casting temperature of 715°C, a casting cooling water flow of 45 t / h, a casting water temperature of 25°C, and an online seeding speed of 370 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain a flat ingot of rare earth-containing aluminum alloy for aviation use.

[0046] The rare earth-containing aluminum alloy flat ingot for aviation obtained in this embodiment has qualified chemical composition, no surface defects such as cracks and slag inclusions, and a yield rate of 87.3%. After rolling, the tensile strength of the plate is increased by 8%, and the yield strength is increased by 12%.

Claims

1. A method for preparing a rare earth-containing aluminum alloy flat ingot for aviation, characterized in that The preparation method of the rare earth aluminum alloy flat ingot for aviation is completed according to the following steps:

1. Weighing: According to the mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.2%-1.5%, Mn: 0.1-0.4%, Mg: 1.5%-3.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 4.5%-7.0%, Zr: 0.11%-0.20%, Sc: 0.10-0.35%, Ti: 0.02-0.10% and the balance is Al, weigh Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy, AlTi6 master alloy as smelting raw materials; 2. Melting: first put Al99.70 aluminum ingot into the melting furnace, then add AlMn10 master alloy, AlZr3 master alloy, AlTi6 master alloy in turn, add AlSc2 master alloy when the melt temperature reaches 800℃ and stir for no less than 15min, then heat to 800℃ again, keep warm at 800℃, stir once every 30min, stir 3 times in total, then add metal Cu, metal Mg, metal Zn into the melting furnace, then stir at 780℃ for 15min, take samples and analyze chemical composition, after the chemical composition is qualified, cover with flux to obtain alloy melt; 3. Casting: The alloy melt is introduced into a holding furnace at a temperature of 780°C, and an argon-chlorine mixed gas is introduced for refining for 30 minutes, and then allowed to stand for 60 minutes to obtain a refined alloy melt. The refined alloy melt is first passed through an online degassing device, then through a filtering device, and then through a flow plate at a casting speed of 50 mm / min, a melt casting temperature of 720°C, a casting cooling water flow of 40 t / h, a casting water temperature of 25°C, and an online seeding speed of 370 mm / min. The melt is injected into a crystallizer for semi-continuous casting to obtain a flat ingot of rare earth-containing aluminum alloy for aviation use.

2. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that In step one, according to the ratio of mass percentage of Si less than 0.18%, Fe less than 0.18%, Cu: 0.32%, Mn: 0.3%, Mg: 2.0%, Cr less than 0.05%, Ni less than 0.05%, Zn: 5.4%, Zr: 0.13%, Sc: 0.14%, Ti: 0.03% and the balance is Al, Al99.70 aluminum ingot, metal Cu, metal Mg, metal Zn, AlMn10 master alloy, AlZr3 master alloy, AlSc2 master alloy and AlTi6 master alloy are weighed as smelting raw materials.

3. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 2, characterized in that In step 1, the Mn content of the AlMn10 master alloy is 10%, the Zr content of the AlZr3 master alloy is 3%, the Sc content of the AlSc2 master alloy is 2%, and the Ti content of the AlTi6 master alloy is 6%.

4. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that In step 2, the flux is composed of 40% KCl, 46% MgCl2, 8% BaCl2, and 6% NaCl+CaCl2 by mass percentage; the amount of flux added is 2 kg / ton of melt.

5. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that The argon-chlorine mixed gas in step 3 consists of 94% argon and 6% chlorine by volume; and the purity of the argon and chlorine are both 99.999%.

6. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 5, characterized in that The introduction rate of the argon-chlorine mixed gas in step 3 is 0.30-0.35 m 3 / min.

7. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that The degassing device in step three is a dual-rotor online degassing device, and the gas in the degassing device is Ar gas with a purity of 99.996%; the filtering device uses a double-stage ceramic filter for filtering, and the double-stage ceramic filter is an imported 30ppi+50ppi.

8. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that In step 3, the Ti content of the online seeded AlTi5B1 wire is 5%, and the B content is 1%.

9. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that In step 3, the shape of the melt injected into the crystallizer is a rectangle of 420 mm×1620 mm.

10. The method for preparing a rare earth-containing aluminum alloy flat ingot for aviation use according to claim 1, characterized in that The size of the rare earth-containing aluminum alloy flat ingot for aviation described in step 3 is 420mm×1620mm×5000mm~6000mm.