5-meter-grade irregular ring and manufacturing method therefor

Abstract

A 5-meter-grade irregular ring and a manufacturing method therefor. The irregular ring is an aluminum-lithium alloy irregular ring, and has an outer diameter of 5000-5500 mm; the tangential tensile strength is 485-587 MPa, the tangential yield strength is 408-536 MPa, and the tangential elongation rate is 5-13%; the axial tensile strength is 485-551 MPa, the axial yield strength is 395-389 MPa, and the axial elongation rate is 5-8%; the radial tensile strength is 493-552 MPa, the yield strength is 440-503 MPa, and the elongation rate is 3-6%. The manufacturing method for the 5-meter-grade irregular ring can manufacture the 5-meter-grade irregular ring, which has large size and high mechanical property in three dimensions.

Description

A 5-meter-class special-shaped ring and its preparation method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 31, 2023, with application number 202311111838.3 and invention name “A 5-meter-grade special-shaped ring and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the technical field of ring preparation, and in particular relates to a 5-meter-grade special-shaped ring and a preparation method thereof. Background Art

[0003] Rings include annular rings and special-shaped rings. Large rings are a key connecting component in many large aerospace vehicles. Larger rings require more sophisticated manufacturing processes. While large rings have seen some development in China, research on large special-shaped rings remains limited. The manufacturing of large special-shaped rings requires higher process requirements than large rings. Previously developed special-shaped rings have not met the performance and dimensions required by this patent. There is an urgent need to develop high-performance, stable, large-scale special-shaped rings.

[0004] Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a 5-meter-class special-shaped ring and a preparation method thereof. The method provided by the present invention can prepare a 5-meter-class special-shaped ring with large size and high three-dimensional mechanical properties.

[0006] The present invention provides a 5-meter-grade special-shaped ring, which is an aluminum-lithium alloy special-shaped ring with an outer diameter of 5000-5500 mm; its tangential tensile strength is 485-587 MPa, the tangential yield strength is 408-536 MPa, and the tangential elongation is 5-13%; its axial tensile strength is 485-551 MPa, the axial yield strength is 395-511 MPa, and the axial elongation is 5-8%; its radial tensile strength is 490-552 MPa, the yield strength is 435-503 MPa, and the elongation is 3-6%.

[0007] The tangential tensile strength of the 5-meter-grade special-shaped ring described in the present invention is preferably not less than 530 MPa; the tangential yield strength is preferably not less than 500 MPa; the tangential elongation is preferably not less than 6%; its axial tensile strength is preferably not less than 510 MPa; the axial yield strength is preferably not less than 470 MPa; the axial elongation is preferably not less than 5%; its radial tensile strength is preferably not less than 490 MPa; the radial yield strength is preferably not less than 435 MPa; and the radial elongation is not less than 4%.

[0008] In certain embodiments of the present invention, the tangential tensile strength of the 5-meter-grade special-shaped ring of the present invention is 560~587MPa; the tangential yield strength is 513~536MPa; the tangential elongation is 7~8%; its axial tensile strength is 539~551MPa; the axial yield strength is 474~489MPa; the axial elongation is 5%; its radial tensile strength is 514~552MPa; the radial yield strength is 486~503MPa; and the radial elongation is 4~6%.

[0009] The 5-meter-class special-shaped ring described in the present invention is an aluminum-lithium alloy special-shaped ring; specifically, its composition includes: less than 0.08wt% Si, less than 0.10wt% Fe, 3.8wt% to 4.2wt% Cu, 0.8wt% to 1.3wt% Li, 0.25wt% to 0.7wt% Mg, 0.25wt% to 0.5wt% Ag, 0.08wt% to 0.16wt% Zr and less than 0.1wt% Ti, with the balance being Al. In one embodiment, the composition of the 5-meter-class special-shaped ring includes: 0.05wt% Si, 0.04wt% Fe, 3.9wt% Cu, 1.0wt% Li, 0.45wt% Mg, 0.3wt% Ag, 0.13wt% Zr and 0.07wt% Ti, with the balance being Al. In one embodiment, the composition of the 5-meter-grade special-shaped ring includes: 0.03wt% Si, 0.04wt% Fe, 3.9wt% Cu, 1.1wt% Li, 0.5wt% Mg, 0.4wt% Ag, 0.11wt% Zr and 0.03wt% Ti, with the balance being Al.

[0010] The 5-meter-class special-shaped ring described in the present invention has an outer diameter of 5000-5500mm; specifically, its height is 500-700mm. More specifically, it consists of a thick-walled hole end portion, a thin-walled hole end portion, and a ring middle portion. The wall thickness of the thick-walled hole end portion is 80-200mm, the wall thickness of the thin-walled hole end portion is 50-120mm, and the wall thickness of the ring middle portion is 50-80mm. The arc radius between the thick-walled hole end portion and the longitudinal cross-section of the ring middle portion is 100-500mm, and the arc taper is 20-40°. The arc radius between the thin-walled hole end portion and the longitudinal cross-section of the ring middle portion is 50-200mm, and the arc taper is 50-60°. The vertical thickness of the longitudinal cross-section of the thick-walled hole end portion before entering the circular arc segment is 30mm, and the vertical thickness of the longitudinal cross-section of the thin-walled hole end portion before entering the circular arc segment is 40mm.

[0011] In one embodiment, the outer diameter of the 5-meter-grade special-shaped ring is 5052+10mm, and the height is 610mm. It consists of a thick-walled hole end part, a thin-walled hole end part and a ring middle part. The wall thickness of the thick-walled hole end part is 180mm, the wall thickness of the thin-walled hole end part is 105mm, and the wall thickness of the ring middle part is 65mm; the arc radius between the thick-walled hole end part and the longitudinal cross-section of the ring middle part is 300mm and the arc taper is 28°; the arc radius between the thin-walled hole end part and the longitudinal cross-section of the ring middle part is 100mm and the arc taper is 53°; the vertical thickness of the longitudinal cross-section of the thick-walled hole end part before entering the arc segment is 30mm, and the vertical thickness of the longitudinal cross-section of the thin-walled hole end part before entering the arc segment is 40mm.

[0012] The 5-meter-class special-shaped ring provided in this application is composed of aluminum-lithium alloy. As a special-shaped ring, it has high three-dimensional mechanical properties while reaching a size of 5 meters, and can meet actual needs.

[0013] The present invention also provides a method for preparing a 5-meter-class special-shaped ring, comprising the following steps:

[0014] S1) punching and flattening an aluminum-lithium alloy cylindrical ingot with a diameter of 900 ± 20 mm and a height of 550 ± 20 mm to obtain a ring with an inner diameter of 500 mm and a height of 520 ± 10 mm;

[0015] S2) processing the center hole of the ring obtained in step S1), heating and expanding the hole, and then rolling and machining the ring multiple times to obtain a 5-meter-class special-shaped ring;

[0016] S3) The 5-meter special-shaped ring obtained in step S2) is subjected to solution quenching at a temperature of 480°C to 520°C for 300min to 600min, cold expansion and aging treatment at a temperature of 145°C to 160°C for 10h to 45h to obtain a 5-meter special-shaped ring.

[0017] The present invention first punches and flattens an aluminum-lithium alloy cylindrical ingot with a diameter of 900±20mm and a height of 550+20mm to obtain a ring with an inner diameter of 500mm and a height of 520+10mm. The aluminum-lithium alloy cylindrical ingot of the present invention is obtained by forging an aluminum-lithium alloy rectangular ingot, with an initial forging temperature of 430-470°C, a final forging temperature ≥350°C, a mold use temperature ≥280°C, and a forging speed of 15mm±5 / s; before forging, the aluminum-lithium alloy rectangular ingot needs to be heated at a temperature of 460±10°C and kept warm for more than 760 minutes. The composition of the aluminum-lithium alloy rectangular ingot of the present invention is similar to that of the above-mentioned 5-meter-class special-shaped ring and will not be repeated here.

[0018] Specifically, the aluminum-lithium alloy cylindrical ingot of the present invention is obtained by the following steps:

[0019] a) upsetting the first, second, and third end faces of an aluminum-lithium alloy rectangular ingot to a height of 820 ± 20 mm, and squared the second and third end faces to 730 ± 10 mm × 730 ± 10 mm; wherein the first end face is a thickness × width face, the second end face is a thickness × length face, and the third end face is a width × length face;

[0020] b) The first end surface of the ingot obtained in step a) is squared, elongated, rounded and upset to obtain an aluminum-lithium alloy cylindrical ingot with a diameter of 900±20 mm and a height of 550+20 mm.

[0021] More specifically, the aluminum-lithium alloy cylindrical ingot is obtained by the following steps:

[0022] a) upsetting the first end face of an aluminum-lithium alloy rectangular ingot having dimensions of 1310 mm in thickness × width × length × 370 mm in width × 1800 mm to a height of 820 mm + 20 mm; square-punching and stretching the second end face to dimensions of 730 ± 10 mm in thickness × length × 730 ± 10 mm, and then upsetting the second end face to a height of 820 mm + 20 mm; square-punching and stretching the third end face to dimensions of 730 ± 10 mm in width × length × 730 ± 10 mm, and then upsetting the third end face to a height of 820 mm + 20 mm; wherein, after the second end face or the third end face is squared and stretched to dimensions of 730 ± 10 mm in width × 730 ± 10 mm in length, the height of the end face is naturally stretched to 2000 mm;

[0023] b) The first end face of the ingot obtained in step a) is squared, elongated and rounded to a diameter of 900±20 mm, and upset to a height of 550+20 mm at the first end face to obtain an aluminum-lithium alloy cylindrical ingot with a diameter of 900±20 mm and a height of 550+20 mm.

[0024] After obtaining the aluminum-lithium alloy cylindrical ingot, the present invention punches and flattens the aluminum-lithium alloy cylindrical ingot to obtain a ring having an inner diameter of 500 mm and a height of 520 + 10 mm. Specifically, the present invention punches a center hole in the aluminum-lithium alloy cylindrical ingot, wherein the eccentricity during centering must be less than 20 mm, and the punching thickness is 100 to 200 mm. After punching the aluminum-lithium alloy cylindrical ingot, the present invention flattens the first end surface of the punched ingot to a height of 520 ± 10 mm, obtaining a ring having an inner diameter of 500 mm and a height of 520 + 10 mm.

[0025] After obtaining a ring with an inner diameter of 500 mm and a height of 520 + 10 mm, the ring is subjected to center hole machining, followed by heating and hole expansion, and then sequentially rolled and machined multiple times to obtain a 5-meter-class special-shaped ring. The center hole machining of the present invention requires that more than 90% of the punching taper be removed.

[0026] Before the heating and hole expansion is carried out, the ring after the center hole is processed needs to be heated at a temperature of 450-470°C, the constant temperature is 460°C, and the heat preservation time is at least 520 minutes. The starting forging temperature of the heating and hole expansion of the present invention is 430-470°C, the final forging temperature of the hole expansion is above 350°C, the final forging temperature of the flattening is above 350°C, and the use temperature of the tool and mold is 250-420°C. The heating and hole expansion of the present invention is specifically as follows: the outer diameter of the ring after the center hole is processed is 2500±50mm after 6-7 rounds of hole expansion at a temperature ≥350°C, the hole expansion reduction of the last round does not exceed 20mm, the hole expansion reduction of the other rounds is 40mm-50mm, the wall thickness difference does not exceed 20mm, and the local protrusion does not exceed 10mm.

[0027] The present invention heats and expands the center hole of the ring, then sequentially rolls and machines it multiple times to produce a 5-meter-grade special-shaped ring. The multiple rolling and machining steps described in the present invention specifically involve performing a first rolling and machining step followed by a second rolling and machining step. Prior to the first rolling step, the ring, after heat expansion, is heated to a temperature of 460-470°C, held at 460°C for at least 300 minutes. The initial rolling temperature for the first rolling step is 430-470°C, and the final rolling temperature is above 350°C. At a temperature of ≥ 350°C, the expanded ring is first rolled in the following order: an outer diameter of 2567mm and a wall thickness of 258mm; an outer diameter of 2765mm and a wall thickness of 231mm; an outer diameter of 3095mm and a wall thickness of 204mm; an outer diameter of 3161mm and a wall thickness of 199mm; and an outer diameter of 3194mm and a wall thickness of 197mm.

[0028] The first machining is performed after the first rolling in the present invention. The first machining is to process the ring after the first rolling into the prototype of a 5-meter special-shaped ring so that it can be further processed into the predetermined 5-meter special-shaped ring structure in subsequent machining.

[0029] The present invention performs the first rolling and the first machining, and then performs the second rolling and the second machining. Before the second rolling, the ring after the second machining needs to be heated, specifically heated at a temperature of 450 to 470°C, fixed at 460°C, and kept warm for at least 200 minutes. The starting rolling temperature of the second rolling of the present invention is 430 to 470°C, and the final rolling temperature is above 350°C. At a temperature ≥350°C, the ring after the first machining is sequentially rolled with an outer diameter of 3282mm and a wall thickness of 193mm, an outer diameter of 3809mm and a wall thickness of 162mm, an outer diameter of 4687mm and a wall thickness of 124mm, an outer diameter of 4862mm and a wall thickness of 124mm, and an outer diameter of 4950mm and a wall thickness of 121mm.

[0030] The purpose of the second machining of the present invention is to further process the ring after the first machining into a predetermined 5-meter special-shaped ring structure. In one embodiment, the outer diameter of the 5-meter special-shaped ring before the second machining and solution quenching is 4950mm, and the height is 600-2mm. It consists of a large hole end part, a small hole end part and a ring middle part. The wall thickness of the large hole end part is 103.5mm, the wall thickness of the small hole end part is 178.5mm, and the wall thickness of the ring middle part is 63.5mm; the arc radius between the longitudinal section of the large hole end part and the ring middle part is 100mm and the arc taper is 53°; the arc radius between the longitudinal section of the small hole end part and the ring middle part is 300mm and the arc taper is 28°; the vertical thickness of the longitudinal section of the large hole end part before entering the arc section is 35mm, and the vertical thickness of the longitudinal section of the small hole end part before entering the arc section is 30-2mm.

[0031] After the second rolling and the second machining, the 5-meter-grade special-shaped ring is obtained. The 5-meter-grade special-shaped ring is then subjected to solution quenching at a temperature of 480°C to 520°C for 300 to 600 minutes, cold bulging, and aging treatment at a temperature of 145°C to 160°C for 10 to 45 hours to obtain the 5-meter-grade special-shaped ring. In certain embodiments of the present invention, the cold bulging rate of the cold bulging is 3.0 to 4.0%, and the outer diameter of the ring after bulging is controlled to be 5052+10 mm.

[0032] In certain embodiments of the present invention, the temperature of the solution quenching is preferably 505°C to 515°C, and the time of the solution quenching is preferably 300 to 400 minutes, more preferably 300 minutes; the temperature of the aging treatment is 145°C to 150°C, and the time of the aging treatment is 30 hours to 45 hours.

[0033] The present invention ultimately produces a 5-meter-grade special-shaped ring through the above-mentioned preparation method; the morphology, structure, composition, and performance of the 5-meter-grade special-shaped ring are the same as those described above and will not be further described. In addition to the steps required for forging and blanking the ingot, the present invention also combines the conditions of solid solution quenching, cold deformation, and aging treatment to meet the requirements of the 5-meter-grade special-shaped ring of the present invention, thereby achieving high performance.

[0034] The present invention provides a 5-meter-grade special-shaped ring and a method for preparing the same. The 5-meter-grade special-shaped ring provided by the present invention is an aluminum-lithium alloy special-shaped ring with an outer diameter of 5000-5500 mm; its tangential tensile strength is 485-587 MPa, its tangential yield strength is 408-536 MPa, and its tangential elongation is 5-13%; its axial tensile strength is 485-551 MPa, its axial yield strength is 395-389 MPa, and its axial elongation is 5-8%; its radial tensile strength is 493-552 MPa, its yield strength is 440-503 MPa, and its elongation is 3-6%. The method provided by the present invention can produce the above-mentioned 5-meter-grade special-shaped ring, which has a large size and high three-dimensional mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a machining diagram of a 5-meter-class special-shaped ring according to the present invention;

[0036] FIG2 is a processing diagram of the 5-meter special-shaped ring blank before quenching according to the present invention. DETAILED DESCRIPTION

[0037] The present invention discloses a 5-meter-class special-shaped ring and a method for preparing the same. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the desired effect. It should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0038] The present invention will be further described below with reference to the embodiments:

[0039] 1.1 Preparation

[0040] 1.1.1 Ingot composition: 2195 alloy, the composition is shown in Table 1:

[0041] Table 1

[0042] 1.1.2 Ingot specifications: 370*1310*1800mm (thickness*width*length);

[0043] 1.1.3 Ingot quality: first-level oxide film, first-level looseness, tempering treatment;

[0044] 1.2 Heating

[0045] 1.2.1 Tool heating: constant temperature 450℃, heating a set of 2300×2200mm flat anvil for at least 16 hours, and heating a Φ500mm long punch for at least 6 hours.

[0046] 1.2.2 Billet heating: heating temperature 460±10℃, constant temperature 460℃; ingot insulation for more than 760 minutes.

[0047] 1.3 Forging

[0048] 1.3.1 Equipment: 10,000-ton open die forging press with a flat anvil.

[0049] 1.3.2 Forging process requirements:

[0050] (1) The start forging temperature is 430-470°C, the final forging temperature is ≥350°C, and the die operating temperature is ≥280°C. Measure and record the start and final forging temperatures for each piece.

[0051] (2) The forging process is as follows: after leaving the furnace, measure the temperature and record the transfer time. The forging speed is 15 mm ± 5 / s. Before forging, use asphalt to mark A (370*1310 mm), B (370*1800 mm), and C (1310*1800 mm) on the surface of the billet.

[0052] (3) Carry out four-pier and three-draw according to forging steps ① to ⑨:

[0053] ① Mark the end surface of the ingot with asphalt A, and upset A to a height of 820 + 20mm

[0054] ② Mark B and C on the side of the ingot with asphalt. Square B and lengthen it (A and C width = 730 ± 10mm, B length about 2000mm)

[0055] ③B upsetting to height = 820 + 20mm

[0056] ④C is squared and lengthened (A, B width = 730 ± 10mm, C length is about 2000mm)

[0057] ⑤C upsetting to height = 820 + 20mm

[0058] ⑥A: Square, stretch, and round to Φ900±20mm

[0059] ⑦A upsetting to height = 550 + 20mm

[0060] ⑧ Use a Φ500 long punch to punch the center hole, use a ruler to align it (eccentricity needs to be ≤20mm), and the punching thickness should be 100~200mm.

[0061] ⑨A leveled to height = 520 ± 10mm

[0062] (4) Stamping: Stamp the alloy, batch, melt order and part number on each blank piece by piece.

[0063] 1.4 Center hole processing

[0064] The remaining material is machined in the machining center and more than 90% of the punching taper is removed.

[0065] 1.5 Heating before expansion

[0066] 1.5.1 Billet heating: heating temperature 460±10℃, constant temperature 460℃, holding time at least 520 minutes.

[0067] 1.5.2 The tool furnace is set at 450℃, and the 1600*1600 small flat anvil and Φ500 mandrel are heated for at least 10 hours; the medium flat anvil is 2300*2200, and heated for at least 16 hours.

[0068] 1.6 Hole expansion

[0069] 1.6.1 Hole expansion equipment and die: 10,000T hydraulic press and 10T forging lathe. The upper die of the 10,000T hydraulic press is mounted on a 1600*1600 small flat anvil. The middle yoke is installed. The yoke must be secured with bolts or other tools. The lower anvil must not be removed, and one side of the middle yoke is close to the lower anvil.

[0070] 1.6.2 Temperature control: Start forging temperature 430~470℃, final forging temperature for hole expansion ≥350℃, final forging temperature for flattening ≥350℃, tool and die operating temperature 250~420℃.

[0071] 1.6.3 Hole Reaming: Use a 10000T hydraulic press with a Φ500 mandrel to ream the ring to an outer diameter of 2500±50mm. This is done in 6-7 turns, with the first few turns reducing the hole by 40-50mm each time. The final turn is a full circle, with a reduction of no more than 20mm. The wall thickness difference should not exceed 20mm, and any local protrusions should not exceed 10mm.

[0072] 1.7 Heating before the first ring rolling

[0073] 1.7.1 Billet heating: heating temperature 460±10℃, constant temperature 460℃, holding time at least 300 minutes.

[0074] 1.8 First Ring Rolling

[0075] 1.8.1 Temperature: Starting rolling temperature 430℃~470℃, finishing rolling temperature ≥350℃.

[0076] 1.8.2 Rolling: Roll the ring to an outer diameter of Φ3200±50mm. The first rolling parameters are shown in Tables 2 to 4:

[0077] Table 2

[0078] Table 3

[0079] Table 4

[0080] 1.8.3 Measure and record the dimensions immediately after rolling.

[0081] 1.9 Machining

[0082] The inner diameter of the ring blank is machined as shown in FIG1 , which is a machining diagram of the 5-meter-class special-shaped ring according to the present invention.

[0083] 1.10 Preparation before the second ring rolling

[0084] The special-shaped core roller needs to be installed before heating the blank.

[0085] 1.11 Heating before the second ring rolling

[0086] Blank heating: heating temperature 460±10℃, constant temperature 460℃, holding time at least 200 minutes.

[0087] 1.12 Second Ring Rolling

[0088] 1.12.1 Temperature: Starting rolling temperature 430℃~470℃, finishing rolling temperature ≥350℃.

[0089] 1.12.2 Rolling: Roll the ring to an outer diameter of Φ4940+10mm. The second rolling parameters are shown in Tables 5 to 7:

[0090] Table 5

[0091] Table 6

[0092] Table 7

[0093] 1.12.3 Measure and record dimensions immediately after rolling.

[0094] 1.13 Machining

[0095] 1.13.1 The upper and lower end surfaces are folded to a height of 600-2mm. The size requirements are shown in Figure 2. Figure 2 is a processing diagram of the 5-meter special-shaped ring before quenching.

[0096] 1.13.2 The circumference of the ring is divided into 8 sections to measure the inner and outer diameters and height dimensions, and the measurement positions are stamped with steel marks.

[0097] 1.14 Solution quenching (before loading the furnace, it is necessary to contact the transport vehicle and outsource the bulging equipment for commissioning)

[0098] 1.14.1 Equipment: Heat treatment furnace with uniformity of ±5℃

[0099] 1.14.2 Quenching system: For solution temperature and time, refer to Table 8. Quenching water temperature is 30-40℃.

[0100] 1.15 Cold expansion

[0101] The cold expansion rate is 3.0-4.0%, and the outer diameter after expansion is controlled to be 5052+10mm.

[0102] 1.16 Artificial aging

[0103] Refer to Table 8 for aging temperature and time, and keep in air for 18 hours.

[0104] Table 8

[0105] The products of Examples 1 to 11 were subjected to performance testing, and the results are shown in Table 9:

[0106] Table 9

[0107] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A 5-meter special-shaped ring, characterized in that: It is an aluminum-lithium alloy shaped ring with an outer diameter of 5000-5500mm; Its tangential tensile strength is 485-587MPa, tangential yield strength is 408-536MPa, and tangential elongation is 5-13%; Its axial tensile strength is 485-551MPa, axial yield strength is 395-511MPa, and axial elongation is 5-8%; Its radial tensile strength is 490-552MPa, its yield strength is 435-503MPa, and its elongation is 3-6%.

2. The 5-meter-class special-shaped ring according to claim 1, characterized in that: The composition of the 5-meter-class special-shaped ring includes: Less than 0.08wt% Si, less than 0.10wt% Fe, 3.8wt% to 4.2wt% Cu, 0.8wt% to 1.3wt% Li, 0.25wt% to 0.7wt% Mg, 0.25wt% to 0.5wt% Ag, 0.08wt% to 0.16wt% Zr and less than 0.1wt% Ti, and the balance is Al.

3. A method for preparing a 5-meter-class special-shaped ring, characterized in that: The following steps are involved: S1) punching and flattening an aluminum-lithium alloy cylindrical ingot with a diameter of 900±20 mm and a height of 550+20 mm to obtain a ring with an inner diameter of 500 mm and a height of 520+10 mm; S2) processing the center hole of the ring obtained in step S1), heating and expanding the hole, and then rolling and machining in sequence for multiple times to obtain a 5-meter-class special-shaped ring; S3) The 5-meter-class special-shaped ring obtained in step S2) is subjected to solution quenching at a temperature of 480°C to 520°C for 300 to 600 minutes, cold expansion and aging treatment at a temperature of 145°C to 160°C for 10 hours to 45 hours to obtain a 5-meter-class special-shaped ring.

4. The preparation method according to claim 3, characterized in that: In step S1), the aluminum-lithium alloy cylindrical ingot is obtained by the following steps: a) upsetting the first end face, the second end face and the third end face of the aluminum-lithium alloy rectangular ingot to a height of 820+20 mm, and square-drawing the second end face and the third end face to 730±10 mm×730±10 mm; wherein the first end face is a thickness×width face, the second end face is a thickness×length face, and the third end face is a width×length face; b) The first end surface of the ingot obtained in step a) is squared, elongated, rounded and upset to obtain an aluminum-lithium alloy cylindrical ingot with a diameter of 900±20 mm and a height of 550+20 mm.

5. The preparation method according to claim 3, characterized in that: In step S3), the temperature of the solution quenching is 505° C. to 515° C., and the time of the solution quenching is 300 to 400 minutes.

6. The preparation method according to claim 3, characterized in that: Step S3) The temperature of the aging treatment is 145°C to 150°C, and the time of the aging treatment is 30h to 45h.

7. The preparation method according to claim 3, characterized in that: In step S2), the heating expansion is specifically as follows: expanding the hole 6 to 7 times at a temperature ≥350°C until the outer diameter is 2500±50mm, the expansion reduction of the last circle does not exceed 20mm, the expansion reduction of other circles is 40mm to 50mm, the wall thickness difference does not exceed 20mm, and the local protrusion does not exceed 10mm.

8. The preparation method according to claim 3, characterized in that: In step S2), the rolling and machining are performed in sequence for multiple times, specifically: After the first rolling and the first machining, the second rolling and the second machining are performed: The first rolling is specifically as follows: at a temperature of ≥350°C, the expanded ring is first rolled in order to have an outer diameter of 2567 mm and a wall thickness of 258 mm, an outer diameter of 2765 mm and a wall thickness of 231 mm, an outer diameter of 3095 mm and a wall thickness of 204 mm, an outer diameter of 3161 mm and a wall thickness of 199 mm, and an outer diameter of 3194 mm and a wall thickness of 197 mm; The second rolling is specifically as follows: at a temperature ≥350°C, the rings after the first machining are rolled for a second time in order with an outer diameter of 3282mm and a wall thickness of 193mm, an outer diameter of 3809mm and a wall thickness of 162mm, an outer diameter of 4687mm and a wall thickness of 124mm, an outer diameter of 4862mm and a wall thickness of 124mm, and an outer diameter of 4950mm and a wall thickness of 121mm.

9. The preparation method according to claim 3, characterized in that: In step S1), the composition of the aluminum-lithium alloy cylindrical ingot includes: Less than 0.08wt% Si, less than 0.10wt% Fe, 3.8wt% to 4.2wt% Cu, 0.8wt% to 1.3wt% Li, 0.25wt% to 0.7wt% Mg, 0.25wt% to 0.5wt% Ag, 0.08wt% to 0.16wt% Zr and less than 0.1wt% Ti, and the balance is Al.

10. The preparation method according to any one of claims 3 to 9, characterized in that: The outer diameter of the 5-meter-class special-shaped ring is 5000-5500 mm; The tangential tensile strength of the 5-meter special-shaped ring is 485-587 MPa, and the tangential yield strength is 408~536MPa, tangential elongation 5~13%; The 5-meter-class special-shaped ring has an axial tensile strength of 485-551 MPa, an axial yield strength of 395-511 MPa, and an axial elongation of 5-8%; The radial tensile strength of the 5-meter special-shaped ring is 490-552 MPa, the yield strength is 435-503 MPa, and the elongation is 3-6%.

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