A low-cost method for preparing wide integral stiffened aluminum-lithium alloy wall panels

Abstract

This invention pertains to the preparation process of high-performance aluminum-lithium alloy materials, specifically a low-cost method for preparing wide-width integral ribbed aluminum-lithium alloy wall panels. A large-size aluminum-lithium alloy ingot is placed in a specialized mold to form a seamless round tube. This round tube is then used as an extrusion blank to be extruded into a seamless round tube with ribs. The ribbed seamless round tube undergoes graded annealing and is then flattened. The flattened wall panel undergoes solution quenching, followed by pre-stretching and treatment to the desired state. This invention enables the preparation of large-size, wide-width integral aluminum-lithium alloy wall panels. By changing the blank preparation method and optimizing the extrusion and heat treatment processes, the utilization rate of aluminum-lithium alloy materials can be significantly improved. Furthermore, the prepared integral wall panel exhibits excellent comprehensive performance and low anisotropy. This method is applicable to the preparation of near-isotropic, low-cost wide-width aluminum-lithium alloy wall panels required in aerospace, aviation, and high-speed rail fields.

Description

Technical Field

[0001] This invention pertains to the preparation process of high-performance aluminum-lithium alloy materials, and relates to a low-cost method for preparing wide-width integral ribbed aluminum-lithium alloy panels. Background Technology

[0002] Employing low-density, high-rigidity aluminum-lithium alloys is a crucial measure for structural weight reduction in the aerospace industry. Simultaneously, to meet the demands of longer service life in the aerospace sector and the reusability of space launch vehicles, large, integral structures are needed to replace traditional welded, riveted, and bolted connections, reducing the weight of the connecting structures and improving structural safety. Considering these requirements, wide-width integral aluminum-lithium alloy panels with reinforcing ribs offer a suitable structural material that simultaneously reduces weight, increases structural reliability, and extends service life.

[0003] For high-performance aluminum-lithium alloys currently used in aviation and aerospace, the fabrication of large-sized (diameter not less than 700mm) hollow ingots is extremely difficult. Therefore, integral ribbed panels with a width exceeding 500mm are mostly machined from large-size plates. For example, a 1200mm wide wing panel requires a 1300mm wide and 80mm thick plate. Some researchers have also tried to fabricate integral ribbed panels by machining large-size solid ingots into hollow ingots and then extruding them. However, due to the high cost of aluminum-lithium alloy materials, both of these methods lead to a large amount of material waste and low material utilization, greatly increasing material costs and restricting the application of aluminum-lithium alloy materials.

[0004] This invention addresses the needs of the aviation and aerospace industries for low structural weight and long service life of main structures. It proposes a low-cost method for preparing wide-width integral ribbed aluminum-lithium alloy wall panels, which yields integral extruded aluminum-lithium alloy wall panels with excellent performance and low anisotropy, while improving material utilization. This method meets the requirements of aviation and aerospace industries for high weight reduction, high reliability, and long service life. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing high-performance aluminum-lithium alloy large-size ingot manufacturing methods, such as the difficulty in fabricating large-size ingots, significant anisotropy in integral extruded panels, and low material utilization. This invention provides a low-cost method for fabricating wide-width integral ribbed aluminum-lithium alloy panels. The goal is to achieve wide-width integral panels with low anisotropy (planar anisotropy index IPA% ≤ 10%) and excellent comprehensive properties (mechanical properties: R...). m ≥460MPa, R 0.2 ≥350MPa, A≥11%, fatigue crack propagation rate: ΔK=33MPa*m 1 / 2 da / dN is not greater than 3.0 × 10 -3mm / cycle, fracture toughness greater than 140 MPa*m 1 / 2 ).

[0006] To solve this technical problem, the technical solution of the present invention is as follows:

[0007] A low-cost method for preparing a wide-width integral ribbed aluminum-lithium alloy wall panel, comprising: placing an aluminum-lithium alloy ingot into a large forging press equipped with forging dies, and preparing a seamless round tube by forging followed by extrusion; using the prepared round tube as an extrusion blank and extruding it into a seamless round tube with ribs in a large extrusion press; subjecting the seamless round tube with ribs to graded annealing, then sawing, unfolding, and leveling; placing the leveled wall panel into a roller hearth furnace for solution quenching, followed by pre-stretching and treatment to the desired state; the preparation steps are as follows:

[0008] Step 1: Preparation of extruded blanks (seamless round tubes) for wall panels:

[0009] Aluminum-lithium alloy round ingots (Φ450~750mm) are heated in a furnace at 400℃~480℃ for 15~30h. Then, they are placed in a forging press with forging dies for forging and reverse extrusion. The die cavity diameter is 800~1400mm and the temperature is 380℃~430℃. The forging head temperature is 410~490℃ and the diameter is 797~1390mm. The stamping head temperature is 380~460℃ and the diameter is consistent with the diameter of the mandrel used in the subsequent extrusion of the wall panel. First, the ingot is forged and deformed into full size by the forging head. Then, the stamping head is replaced with a stamping head, and a seamless round tube with an outer diameter of 800mm~1400mm is produced by reverse extrusion.

[0010] Step 2: Preparation of Ribbed Seamless Tubes

[0011] The seamless round tube prepared in step one is placed in an air-circulating furnace and heated to 450℃~490℃ for 5~12h. After being taken out of the furnace, it is placed in a large extruder for extrusion. The extrusion die temperature is 440℃~480℃, the mandrel temperature is 460~480℃, the extrusion bar temperature is 430℃~450℃, the extrusion cylinder temperature is 440℃~470℃, and the exit speed is 0.5~1.5m / min.

[0012] The mandrel, extrusion bar, and extrusion cylinder are all part of the extrusion press and have temperature requirements. After the tube passes through the extrusion press outlet, a seamless round tube with ribs with an inner diameter of 550mm to 800mm is obtained, and the rib height is 15 to 100mm.

[0013] Step 3: Unfolding the wall panels:

[0014] The ribbed seamless round tube after being processed in Step 2 is subjected to a grading annealing treatment. The annealing process is as follows: put it into the furnace when it reaches the temperature, the furnace gas temperature is 500 - 530 °C, keep it warm for 30 - 60 minutes after reaching the temperature, then reduce the furnace temperature to 400 - 440 °C and keep it warm for 2 - 4 hours. Subsequently, cool it slowly with the furnace at a cooling rate not exceeding 60 °C / h to 200 °C, and then take it out of the furnace and air-cool it to room temperature; the requirement for slow cooling is that the cooling rate does not exceed 60 °C / h.

[0015] Saw the annealed pipe longitudinally, unfold and shape it to be flat to obtain the integral wall panel;

[0016] By using an aluminum-lithium alloy round ingot with a specification of Φ450 - 750 mm in Step 1, a seamless round tube with an outer diameter of 800 mm - 1400 mm is prepared; and a ribbed seamless round tube with an inner diameter size of 550 mm - 800 mm is obtained through Step 2; finally, the width of the integral wall panel obtained through Step 3 reaches 1700 mm - 2500 mm.

[0017] Step 4: Solution quenching treatment:

[0018] The integral wall panel after being processed in Step 3 is subjected to a solution treatment. The furnace gas temperature is 505 - 545 °C, and after reaching the temperature, set the holding time according to the maximum metal cross-section thickness T on the wall panel. Specifically:

[0019] When T ≤ 5 mm, the holding time is 7 - 10×T min,

[0020] When 5 < T ≤ 15 mm, the holding time is 5 - 7×T min, <​​​​​​​​​​​​​​​​​​​​​

[0028] In step one, the aluminum-lithium alloy round ingots are prepared by spray deposition / melting casting, and after homogenization and peeling, they are placed in an air-circulating heating furnace for heating.

[0029] In step two, after the pipe passes through the extruder outlet, it is pulled by a traction machine and cooled online by water mist or a fan.

[0030] Preferably, the third step, graded annealing, is performed by heating in an air-circulating furnace.

[0031] Preferably, in step three, the material is flattened and straightened to a flatness on a large press or rolling mill equipped with a unfolding mold.

[0032] Preferably, in step four, the integral wall panel is placed on a fixing fixture and subjected to solution treatment in a roller hearth furnace. This fixing fixture is designed according to the cross-sectional shape of the wall panel. Its purpose is to prevent the wall panel from directly contacting the roller hearth furnace and causing surface damage. At the same time, the fixing fixture makes it easier for the wall panel to enter the furnace and reduces deformation during heating and quenching.

[0033] In step four, cooling is achieved using spray water cooling, with the cooling water temperature ranging from 20°C to 60°C.

[0034] In step five, choose one of the following time-sensitive processing options:

[0035] Natural aging involves placing the product at room temperature for more than 96 hours to achieve a T3 state; or artificial aging can be performed to achieve a T8 state. The artificial aging process involves 135–175℃ and a holding time of 14–32 hours.

[0036] Preferably, the pre-stretching treatment in step five is performed on a pre-stretching machine.

[0037] The aluminum-lithium alloy integral wall panel prepared using the method of this invention can achieve a maximum width of 1600 mm and a length of 11000–13000 mm. The prepared wide integral wall panel exhibits low anisotropy (planar anisotropy index IPA% ≤ 10%) and excellent comprehensive properties (mechanical properties: R...). m ≥460MPa, R 0.2 ≥350MPa, A≥11%, fatigue crack propagation rate: ΔK=33MPa*m 1 / 2 da / dN is not greater than 3.0 × 10 -3 mm / cycle, fracture toughness greater than 140 MPa*m 1 / 2 ).

[0038] The aluminum-lithium alloy composition and mass percentage of each component applicable to the method of this invention are as follows: Cu 2.5-4.5%, Mg 0.4-1.8%, Li 0.8-2.2%, Zr 0.08-0.20%, Mn 0.2-0.6%, Zn 0.15-0.45%, Ti 0.01-0.05%, and Ag 0.2-0.6%, Sc 0.03-0.25%, any one or two of the following: impurity elements Si≤0.10%, Fe≤0.12%, other impurities individually≤0.05%, total ≤0.15%, and the balance is Al.

[0039] The beneficial effects of this invention are:

[0040] This invention utilizes a die forging process to transform small-sized aluminum-lithium alloy ingots into large-sized ingots, reducing ingot preparation difficulty and improving metallurgical quality. A die reverse extrusion process produces large-sized seamless cylindrical tubes as extrusion blanks for subsequent wall panels, significantly improving material utilization. Combined with subsequent online cooling and staged annealing processes, the anisotropy caused by the extrusion effect can be minimized, resulting in a low-anisotropy aluminum-lithium alloy integral extruded wall panel with excellent performance. Specifically,

[0041] 1. This invention can reduce the size of the ingots required for integral aluminum-lithium alloy wall panels and significantly improve material utilization. Compared with plate machining and the processing of large-size ingots into hollow ingots, the method of this invention is simpler and easier to implement, while also significantly improving material utilization (see specific implementation methods for a detailed comparison).

[0042] 2. The integral wall panels prepared by this invention are large in size and possess low anisotropy and high comprehensive performance. The aluminum-lithium alloy integral wall panels prepared by the method of this invention can reach a maximum width of 2500mm and a length of 11000-13000mm. The tensile strength anisotropy (IPA%) does not exceed 10%, and the fatigue, fracture, and corrosion resistance properties are excellent. They are comparable to the mechanical properties, fatigue properties, and corrosion resistance properties of wide wall panels prepared by machining large-size plates in the traditional way, while improving the material utilization rate by 80%. Attached Figure Description

[0043] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0044] Figure 1 The high-magnification microstructures of the longitudinal and cross-sections of the wall panel prepared by the method of the present invention in Example 1 are shown in (a) as the longitudinal section and (b) as the cross-section. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention.

[0047] In the various accompanying drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessarily obscuring the invention.

[0048] Example 1

[0049] The low-cost aluminum-lithium alloy integral wall panel method involved in this invention is used to prepare an aluminum-lithium alloy integral wall panel for fuselage skin.

[0050] First, the alloy composition was determined to be Cu 3.3%, Mg 1.0%, Li 1.5%, Zr 0.11%, Mn 0.45%, Zn 0.25%, Ti 0.03%, Ag 0.3%, Si 0.06%, Fe 0.11%, other impurities ≤0.05% individually, ≤0.15% in total, balance Al. After homogenization and peeling, aluminum-lithium alloy ingots with dimensions of Φ600×2000mm are placed in an air-circulating furnace for heating at 450℃ for 8 hours. After heating, the ingot is removed and vertically placed into a forging die with a diameter of Φ820mm for forging at a die temperature of 410℃. The forging head has a diameter of 816mm and a temperature of 440℃. After multiple forgings until the die is completely filled, a stamping head is installed for reverse extrusion at a temperature of 430℃. A seamless round tube with an outer diameter of Φ820mm, an inner diameter of Φ560mm, and a wall thickness of 130mm is produced by stamping.

[0051] After extrusion, the round tube is machined to make both ends flush and remove surface oil and scratches, resulting in an extrusion billet with an outer diameter of Φ810mm and an inner diameter of Φ565mm. The extrusion billet is placed in an air-circulating furnace for heating. After the metal temperature reaches 480℃, it is held at that temperature for 6 hours. After exiting the furnace, it is placed in a 10,000-ton large extrusion press for extrusion. The extrusion die temperature is 460℃, the mandrel diameter is 558mm and its temperature is 470℃, the extrusion rod temperature is 450℃, the extrusion cylinder temperature is 470℃, and the exit speed is 1.0m / min. The extrusion produces a seamless cylindrical tube with 6 ribs, a rib height of 60mm, a cylinder thickness of 5mm, and a maximum cross-sectional thickness of 8mm. After the ribbed cylinder protrudes from the extrusion press exit, it is pulled by a traction machine and cooled by online water mist.

[0052] After the seamless round tube with ribs is sawn at both ends, it is placed in an air-circulating furnace for annealing. The annealing process involves placing the tube into the furnace at the set temperature (515℃), holding it at that temperature for 45 minutes, then lowering the furnace temperature to 420℃ and holding it for 2–4 hours. The tube is then slowly cooled to 200℃ at a rate of 45℃ / h, and finally air-cooled to room temperature. After annealing, the tube is longitudinally sawn at a pre-set location (preferably between two ribs with a certain dimensional allowance). It is then unfolded and shaped to a flat surface on a large press equipped with an unfolding mold.

[0053] After the unfolded wall panel is placed into the fixed fixture, it is sent into the roller hearth furnace for solution treatment. The furnace gas temperature is 525℃. After the metal reaches the temperature, it is held at that temperature for 50 minutes. Then it is taken out of the furnace at a speed of 300mm / s and sprayed with water for cooling. The cooling water temperature is 23℃.

[0054] After quenching, the integral wall panel is removed from the fixture and placed in a pre-stretching machine for pre-stretching treatment. The pre-stretching deformation is 3.0%. After pre-stretching, it is placed at room temperature for 96 hours to reach the T3 state.

[0055] The overall wall panel was cut off from the stretching jaws, the total weight was weighed, and the material utilization rate was calculated by comparing it with the initial ingot weight. The utilization rate was then compared with that of wall panels prepared from thick plates and solid ingots, as shown in Table 1. It can be seen that the overall wall panel prepared by the method of the present invention has a significantly improved material utilization rate.

[0056] Samples were taken from the integral extruded panel to measure the tensile properties in the extrusion direction, at 45° to the extrusion direction, and perpendicular to the extrusion direction; simultaneously, the fatigue crack propagation rate and fracture toughness (K0) of the integral extruded panel were measured. c The results are shown in Table 2. The high-magnification microstructure of the longitudinal and transverse directions of the wall panel is as follows: Figure 1 As shown, the integral stiffened aluminum-lithium alloy wall panel prepared by the method of this invention exhibits low anisotropy, low fatigue crack propagation rate, and high fracture toughness. The grain structure is fine and equiaxed.

[0057] Table 1. Utilization rate of the wide integral wall panel material prepared in this invention.

[0058] Serial Number Preparation method Material utilization rate from ingot to finished product, % 1 Thick plate machining methods 7.6 2 Solid ingot machining 38 3 The method of the present invention 67

[0059] Table 2. Performance test results of the T3 state integral wall panel prepared using the present invention.

[0060]

[0061] Example 2

[0062] The rocket's section skin is prepared using the low-cost aluminum-lithium alloy integral wall panel method involved in this invention.

[0063] First, the alloy composition was determined to be Cu 3.0%, Mg 0.6%, Li 1.1%, Zr 0.09%, Mn 0.25%, Zn 0.20%, Ti 0.04%, Ag 0.4%, Sc 0.15%, Si 0.05%, and Fe. 0.07%, other impurities ≤0.05% individually, total ≤0.15%, balance Al. After homogenization and peeling, aluminum-lithium alloy ingots with dimensions of Φ450×1800mm are placed in an air-circulating furnace for heating at 470℃ for 5 hours. After heating, the ingot is removed and vertically placed into a forging die with a diameter of Φ660mm for forging at 420℃. The forging head has a diameter of 656mm and a temperature of 460℃. After multiple forgings until the die is completely filled, a stamping head is installed for reverse extrusion at a temperature of 420℃. A seamless round tube with an outer diameter of Φ660mm, an inner diameter of Φ440mm, and a wall thickness of 115mm is produced by stamping.

[0064] After extrusion, the round tube is machined to make both ends flush and remove surface oil and scratches, resulting in an extrusion billet with an outer diameter of Φ650mm and an inner diameter of Φ435mm. The extrusion billet is placed in an air-circulating furnace for heating. After the metal temperature reaches 450℃, it is held at that temperature for 4 hours. After exiting the furnace, it is placed in a 10,000-ton large extrusion press for extrusion. The extrusion die temperature is 430℃, the mandrel diameter is 432mm and its temperature is 440℃, the extrusion rod temperature is 420℃, the extrusion cylinder temperature is 440℃, and the exit speed is 1.5m / min. The extrusion produces a seamless cylindrical tube with four ribs, each rib height is 80mm, the cylinder wall thickness is 3mm, and the maximum cross-sectional thickness is 5mm. After the ribbed cylinder protrudes from the extrusion press exit, it is pulled by a traction machine and cooled online by air.

[0065] After the seamless round tube with ribs is sawn at both ends, it is placed in an air-circulating furnace for annealing. The annealing process involves placing the tube into the furnace at the required temperature (520℃), holding it at that temperature for 30 minutes, then lowering the furnace temperature to 430℃ and holding it for 2 hours. It is then slowly cooled in the furnace to 200℃ at a rate of 55℃ / h, and finally air-cooled to room temperature. After annealing, the tube is longitudinally sawn and then rolled and shaped to a flat surface on a rolling mill equipped with rolling rollers.

[0066] After the unfolded wall panel is placed into the fixed fixture, it is sent into the roller hearth furnace for solution treatment. The furnace gas temperature is 545℃. After the metal reaches the temperature, it is held at that temperature for 35 minutes. Then it is taken out of the furnace at a speed of 400mm / s and sprayed with water for cooling. The cooling water temperature is 35℃.

[0067] After quenching, the integral wall panel is removed from the fixed fixture and placed in a pre-stretching machine for pre-stretching treatment. The pre-stretching deformation is 2.5%. After pre-stretching, it is placed in an aging furnace with air circulation for artificial aging treatment. The aging process is 155℃ / 24h. After aging, it is taken out of the furnace and air-cooled to room temperature to reach the T8 state.

[0068] Samples were taken from the integral extruded panel to measure the tensile properties in the extrusion direction, at 45° to the extrusion direction, and perpendicular to the extrusion direction; simultaneously, the fatigue crack propagation rate and fracture toughness (K0) of the integral extruded panel were measured. c The results are shown in Table 3. It can be found that the aluminum-lithium alloy integral stiffened wall panel prepared by the method of the present invention has low anisotropy, low fatigue crack propagation rate, and high fracture toughness.

[0069] Table 3. Performance test results of the T8 state integral wall panel prepared using the present invention.

[0070]

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A low-cost method for preparing a wide-width integral ribbed aluminum-lithium alloy wall panel, characterized in that, The method describes the process of preparing seamless round tubes from aluminum-lithium alloy ingots by forging and then extruding them using a large forging press. The prepared round tubes are then used as extrusion blanks in a large extrusion press to form seamless round tubes with ribs. The ribbed seamless round tubes undergo graded annealing, followed by sawing, unfolding, and leveling. The leveled wall panels are then placed in a roller hearth furnace for solution quenching. After quenching, they are pre-stretched and processed to the desired state. The applicable aluminum-lithium alloy composition and the mass percentage of each component are as follows: Cu 2.5–4.5%, Mg 0.4–1.8%, Li 0.8–2.2%, Zr 0.08–0.20%, Mn 0.2–0.6%, Zn 0.15–0.45%, Ti 0.01–0.05%, and Ag 0.2–0.6%, Sc Any one or two impurities in the range of 0.03% to 0.25%, with Si ≤ 0.10%, Fe ≤ 0.12%, other impurities ≤ 0.05% individually and ≤ 0.15% in total, and the balance being Al; The preparation steps are as follows: Step 1: Preparation of extruded blanks for wall panels: Aluminum-lithium alloy round ingots with a diameter of φ450~750mm are heated in a heating furnace at a temperature of 400℃~480℃ for 15~30h. Then, they are placed in a forging press equipped with a forging die for forging and reverse extrusion. The die cavity diameter is 800~1400mm and the temperature is 380℃~430℃. The forging head temperature is 410~490℃ and the diameter is 797~1390mm. The stamping head temperature is 380~460℃ and the diameter is consistent with the diameter of the mandrel used in the subsequent extrusion of the wall panel. First, the ingot placed in the forging die is forged and deformed by the forging head. Then, the stamping head is replaced and a seamless round tube is prepared by reverse extrusion. Step 2: Preparation of Ribbed Seamless Tubes The seamless round tube prepared in step one is placed in an air-circulating furnace and heated to 450℃~490℃ for 5~12 hours. After exiting the furnace, it is placed in a large extruder for extrusion. The extrusion die temperature is 440℃~480℃, the mandrel temperature is 460~480℃, the extrusion bar temperature is 430℃~450℃, the extrusion cylinder temperature is 440℃~470℃, and the exit speed is 0.5~1.5m / min. After the tube passes through the extruder outlet, a ribbed seamless round tube with an inner diameter of 550mm~800mm and a rib height of 15~100mm is obtained. Online cooling is performed using water mist or a fan. Step 3: Unfolding the wall panels: The seamless round tube with ribs after step two is subjected to graded annealing. The annealing process is as follows: the tube is put into the furnace at the temperature of 500-530℃, and after reaching the temperature, it is held for 30-60 minutes. The furnace temperature is then reduced to 400-440℃ and held for 2-4 hours. Subsequently, it is slowly cooled to 200℃ in the furnace at a cooling rate not exceeding 60℃ / h, and then air-cooled to room temperature after being taken out of the furnace. After annealing, the pipe is cut longitudinally, unfolded and straightened to a flat surface to obtain an integral wall panel. Step 4: Solution quenching treatment: After step three, the entire wall panel undergoes solution treatment at a furnace gas temperature of 505~545℃. Once the temperature is reached, the holding time is set according to the maximum metal cross-sectional thickness T on the wall panel. For T≤5mm, the heat preservation time is (7~10)×Tmin. 5 < T ≤ 15 mm, the heat preservation time is (5~7) × T min. For a temperature T > 15 mm, the heat preservation time is (3~4) × Tmin; After the heat preservation is complete, quickly remove the product from the oven and allow it to cool. Step 5: Pre-stretching and aging treatment: The overall wall panel processed in step four undergoes pre-stretching treatment, with the stretching deformation controlled within the range of 2.5% to 6.5%. After pre-stretching, aging treatment is performed.

2. The preparation method according to claim 1, characterized in that, The large extrusion press is a 10,000-ton extrusion press with an extrusion cylinder diameter of 650~1000mm.

3. The preparation method according to claim 1, characterized in that, In step one, the aluminum-lithium alloy round ingots are prepared by spray deposition / melting casting, and after homogenization and peeling, they are placed in an air-circulating heating furnace for heating.

4. The preparation method according to claim 1, characterized in that, In step two, after the pipe passes through the extrusion press outlet, it is pulled by a traction machine.

5. The preparation method according to claim 1, characterized in that, Step 3: Flatten and straighten the material on a large press or rolling mill equipped with a unfolding mold until it is flat.

6. The preparation method according to claim 1, characterized in that, In step four, the integral wall panel is fixed in the roller hearth furnace using a fixing fixture for solution treatment; the shape of the fixing fixture is consistent with the cross-sectional shape of the wall panel.

7. The preparation method according to claim 1, characterized in that, In step four, cooling is achieved using spray water cooling, with the cooling water temperature ranging from 20°C to 60°C.

8. The preparation method according to claim 1, characterized in that, In step five, choose one of the following time-sensitive processing options: Natural aging involves placing the product at room temperature for more than 96 hours to achieve a T3 state; or artificial aging can be performed to achieve a T8 state. The artificial aging process involves 135~175℃ and a holding time of 14~32 hours.

9. A wide-width integral ribbed aluminum-lithium alloy wall panel, characterized in that, Prepared according to the method described in claim 1, the wide integral stiffened panel has a planar anisotropy index (IPA%) ≤ 10% and mechanical properties: R m ≥460MPa, R 0.2 ≥350MPa, A≥11%, fatigue crack propagation rate: ΔK=33MPa*m 1 / 2 da / dN is not greater than 3.0 × 10 -3 mm / cycle, fracture toughness greater than 140 MPa*m 1 / 2 .

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