7050 aluminum alloy ring forging and manufacturing method thereof

Abstract

The present invention relates to the technical field of metal material processing, and in particular to a 7050 aluminum alloy ring forging and a method for manufacturing the same. The method for manufacturing the 7050 aluminum alloy ring forging comprises the following steps: (a) subjecting a 7050 aluminum alloy bar blank to a heat treatment and then subjecting it to multi-directional forging to obtain a blank; (b) punching the blank to obtain a ring blank; heating the ring blank and then subjecting it to pre-rolling and roll forming to obtain a ring blank; (c) subjecting the ring blank to a two-stage solid solution treatment, followed by cold expansion, and then artificial aging treatment. The present invention uses composite strengthening methods such as fine grain strengthening, solid solution strengthening, and aging strengthening to improve the tensile properties of the 7050 alloy ring forging in the tangential, axial, and radial directions, so that the three-dimensional mechanical properties of the forging can simultaneously meet the new requirements of 7050 alloy parts for aerospace use: tensile strength ≥560MPa, yield strength ≥470MPa, and elongation after fracture ≥5%.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing, in particular to a 7050 aluminum alloy ring forging and a manufacturing method thereof. Background Art

[0002] 7050 aluminum alloy is a high-strength aluminum alloy primarily used in high-tech fields such as aerospace and rail transit, requiring high comprehensive performance in terms of strength, toughness, and corrosion resistance. The current production process for 7050 aluminum alloy ring forgings is as follows: billeting → blanking → heating (generally at 420-440°C) → blanking (upsetting and punching) → rolling. Subsequently, solutionizing, cold forming, and artificial aging treatments are performed to achieve performance that meets application requirements. 7050 alloy ring forgings produced using existing processes typically have a tensile strength between 460 and 530 MPa, rarely exceeding 560 MPa. Furthermore, the elongation in the tangential, transverse, and axial directions varies significantly, with the axial elongation typically only 2% to 4%, failing to meet the new requirements for 7050 alloy parts used in aerospace.

[0003] 7050 aluminum alloys contain high levels of Zn, Mg, and Cu. These strengthening phase-forming elements tend to accumulate at the grain boundaries of the cast structure, forming brittle, low-melting-point intergranular phases. Furthermore, impurity elements such as Fe, Mn, and Si accumulate along the grain boundaries, leading to grain boundary embrittlement, which is difficult to eliminate using conventional forging heating methods. During forging and heat treatment, these intergranular phases and brittle grain boundaries induce crack initiation, resulting in forging failures. Furthermore, the concentration of strengthening phase-forming elements at the grain boundaries reduces the content of these strengthening phase-forming elements in the matrix, diminishing the effectiveness of aging strengthening and resulting in lower tensile strength in the forgings. To minimize the effects of these intergranular phases and brittle grain boundaries on the performance of 7050 aluminum alloy forgings, homogenization annealing is commonly used. After homogenization annealing, the alloy is typically cooled to room temperature and then heated to the forging heating temperature, where it is then held for heating and then forging. Homogenization annealing cycles typically take 20 to 30 hours or even longer, resulting in low production efficiency and high overall costs.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] An object of the present invention is to provide a method for manufacturing 7050 aluminum alloy ring forgings to solve the technical problems in the prior art such as insufficient performance of 7050 alloy ring forgings and low product qualification rate caused by easy cracking during forging and heat treatment.

[0006] Another object of the present invention is to provide a 7050 aluminum alloy ring forging having excellent tensile properties.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0008] A method for manufacturing a 7050 aluminum alloy ring forging comprises the following steps:

[0009] (a) heating a 7050 aluminum alloy billet and then performing multi-directional forging to obtain a billet; the heating treatment comprising: maintaining the billet at 460° C. to 482° C. for 12 to 15 hours, and then maintaining the billet at 420° C. to 442° C. for 3 to 5 hours;

[0010] (b) punching the blank to obtain a ring blank; heating the ring blank at 420-440° C. and then pre-rolling the ring blank; and then heating the pre-rolled blank at 420-440° C. and then rolling the pre-rolled blank to obtain a ring blank;

[0011] (c) subjecting the ring blank obtained in step (b) to a two-stage solution treatment, followed by cold bulging and then artificial aging treatment;

[0012] The multi-directional forging includes: performing at least one drawing and upsetting along the axial direction, one radial direction and another radial direction of the rod blank, and then drawing along the axial direction to obtain a blank; the deformation amount of upsetting in each direction is 25% to 55%, and the deformation amount of drawing in each direction is 25% to 60%; the one radial direction is perpendicular to the other radial direction.

[0013] The manufacturing method of the 7050 aluminum alloy ring forging of the present invention first performs high-temperature heating at 460-482°C during forging heating, so that the grain boundary phase and impurity elements are fully dissolved into the matrix through diffusion, and then the temperature is lowered to 420-442°C for heat preservation, thereby improving the uniformity of alloy elements at the grain boundaries and within the grains, reducing grain boundary brittleness, greatly avoiding the problem of product scrapping caused by cracking of the blank during forging and heat treatment, and improving the qualified rate of forgings; at the same time, compared with the traditional process of heating and forging after homogenization annealing, production efficiency is significantly improved. By controlling the forging method and the deformation amount of upsetting and drawing, the uniformity of the temperature field and strain field of the blank during the forging process is improved, thereby obtaining a more uniform and fine grain structure, and utilizing the fine grain strengthening mechanism to improve the tensile strength and plasticity of the forging.

[0014] In a specific embodiment of the present invention, in step (a), the heat treatment comprises: keeping warm at 460-470°C for 8-10 hours, then keeping warm at 475-482°C for 4-5 hours, and then keeping warm at 420-442°C for 3-5 hours.

[0015] In a specific embodiment of the present invention, the initial forging temperature of the multi-directional forging is 400-440°C, and the final forging temperature is ≥360°C.

[0016] In a specific embodiment of the present invention, during the upsetting process of the multi-directional forging, multiple down-upsetting operations are performed until a preset deformation amount is reached; wherein each down-upsetting operation is 50 to 80 mm, and there is a pause of 4 to 8 seconds between two adjacent down-upsetting operations.

[0017] In a specific embodiment of the present invention, the punching process includes a punch having a diameter of 185 to 250 mm and a conical outer surface with an angle of 2 to 3 degrees. The small end of the punch is pressed into the blank to a depth of 2 / 3 to 3 / 4 of the blank's height. The blank with the punch is then turned over and placed into a punching die. The large end of a punch of the same size is then aligned and pressed into the blank to remove the core material.

[0018] In a specific embodiment of the present invention, during the pre-rolling, the rolling deformation is 30% to 60%. During the pre-rolling process, the height of the blank in the axial direction does not decrease.

[0019] In a specific embodiment of the present invention, during the roll forming, the rolling deformation is 35% to 60%. During the roll forming, the height of the blank is reduced by 4 to 8 mm before and after rolling.

[0020] In a specific embodiment of the present invention, the two-stage solution treatment comprises: keeping the ring blank at 465-470° C. for 4-6 hours, then keeping it at 475-482° C. for 6-10 hours, and water cooling.

[0021] In a specific embodiment of the present invention, the transfer time of the ring billet out of the furnace is ≤10s; in the water cooling, the water temperature is 35-65°C, and the cooling time in water is 5-30min.

[0022] In a specific embodiment of the present invention, the cold expansion amount of the cold expansion is 2% to 4%. The cold expansion amount is calculated as (d3-d2) / d2, that is, 2%≤(d3-d2) / d2≤4%, d2 is the inner diameter of the ring blank after rolling, and d3 is the inner diameter of the ring blank after cold expansion.

[0023] In a specific embodiment of the present invention, the cold bulging is completed within 3 hours after the double-stage solution treatment.

[0024] In a specific embodiment of the present invention, the artificial aging treatment system is an existing standard two-stage aging system.

[0025] The present invention also provides a 7050 aluminum alloy ring forging manufactured by any one of the above methods.

[0026] In a specific embodiment of the present invention, the tangential, axial and radial tensile properties of the 7050 aluminum alloy ring forging all meet the following requirements: tensile strength ≥560 MPa, yield strength ≥470 MPa, and elongation after fracture ≥5%.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The manufacturing method of the present invention adopts certain heating conditions to greatly avoid the problem of product scrapping caused by cracking of the blank during forging and heat treatment, thereby improving the qualified rate of forgings; at the same time, compared with the traditional process of homogenizing annealing followed by heating and forging, the production efficiency is significantly improved;

[0029] (2) The manufacturing method of the present invention improves the uniformity of the temperature field and strain field of the billet during the forging process by controlling the forging method and the deformation amount of upsetting and drawing, thereby obtaining a more uniform and fine grain structure and utilizing the fine grain strengthening mechanism to improve the tensile strength and plasticity of the forging;

[0030] (3) The present invention adopts composite strengthening means such as fine grain strengthening, solid solution strengthening and aging strengthening to improve the tensile properties of 7050 alloy ring forgings in the tangential, axial and radial directions, so that the three-dimensional mechanical properties of the forgings can simultaneously meet the new requirements of 7050 alloy parts for aerospace use: tensile strength ≥560MPa, yield strength ≥470MPa, and elongation after fracture ≥5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a heating curve for the heating treatment of step (1) provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of multi-directional forging in step (1) provided in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of a heating curve for the two-stage solution treatment in step (4) provided in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the heating curve of the artificial aging treatment (standard aging system) in step (6) provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0037] A method for manufacturing a 7050 aluminum alloy ring forging comprises the following steps:

[0038] (a) heating a 7050 aluminum alloy billet and then performing multi-directional forging to obtain a billet; the heating treatment comprising: maintaining the billet at 460° C. to 482° C. for 12 to 15 hours, and then maintaining the billet at 420° C. to 442° C. for 3 to 5 hours;

[0039] (b) punching the blank to obtain a ring blank; heating the ring blank at 420-440° C. and then pre-rolling the ring blank; and then heating the pre-rolled blank at 420-440° C. and then rolling the pre-rolled blank to obtain a ring blank;

[0040] (c) subjecting the ring blank obtained in step (b) to a two-stage solution treatment, followed by cold bulging and then artificial aging treatment;

[0041] The multi-directional forging includes: performing at least one drawing and upsetting along the axial direction, one radial direction and another radial direction of the rod blank, and then drawing along the axial direction to obtain a blank; the deformation amount of upsetting in each direction is 25% to 55%, and the deformation amount of drawing in each direction is 25% to 60%; the one radial direction is perpendicular to the other radial direction.

[0042] The manufacturing method of the 7050 aluminum alloy ring forging of the present invention first performs high-temperature heating at 460-482°C during forging heating, so that the grain boundary phase and impurity elements are fully dissolved into the matrix through diffusion, and then the temperature is lowered to 420-442°C for heat preservation, thereby improving the uniformity of alloy elements at the grain boundaries and within the grains, reducing grain boundary brittleness, greatly avoiding the problem of product scrapping caused by cracking of the blank during forging and heat treatment, and improving the qualified rate of forgings; at the same time, compared with the traditional process of heating and forging after homogenization annealing, production efficiency is significantly improved. By controlling the forging method and the deformation amount of upsetting and drawing, the uniformity of the temperature field and strain field of the blank during the forging process is improved, thereby obtaining a more uniform and fine grain structure, and utilizing the fine grain strengthening mechanism to improve the tensile strength and plasticity of the forging.

[0043] For example, in different embodiments, in the multi-directional forging, the deformation amount of upsetting in each direction can be 25%, 30%, 35%, 40%, 45%, 50%, 55% and the like; the deformation amount of drawing in each direction can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and the like.

[0044] In a specific embodiment of the present invention, in step (a), the heat treatment comprises: keeping warm at 460-470°C for 8-10 hours, then keeping warm at 475-482°C for 4-5 hours, and then keeping warm at 420-442°C for 3-5 hours.

[0045] For example, in different embodiments, in step (a), the heat treatment may include: keeping warm at a temperature of 460°C, 462°C, 464°C, 465°C, 466°C, 468°C or 470°C, etc. for 8h, 9h, 10h, 11h or 12h, etc., and then keeping warm at a temperature of 475°C, 476°C, 478°C, 480°C or 482°C, etc. for 4h, 4.5h or 5h, etc., and then keeping warm at a temperature of 420°C, 422°C, 424°C, 425°C, 426°C, 428°C, 430°C, 432°C, 434°C, 435°C, 436°C, 438°C, 440°C or 442°C, etc. for 3h, 3.5h, 4h, 4.5h or 5h, etc.

[0046] In a specific embodiment of the present invention, in step (a), the heating treatment is carried out in a warm furnace.

[0047] In actual operation, in step (a), during the heating process, the heating rate from 460-470°C to 475-482°C can be 0.2-5°C / min; the cooling rate from 475-482°C to 420-442°C can be 0.1-3°C / min.

[0048] In a specific embodiment of the present invention, the initial forging temperature of the multi-directional forging is 400-440°C, and the final forging temperature is ≥360°C.

[0049] In actual operation, in step (a), when the multi-directional forging is performed after the heat treatment and the steel is taken out of the furnace, the initial forging temperature can be 400°C, 405°C, 410°C, 415°C, 420°C, 425°C, 430°C, 435°C, 440°C, etc.

[0050] For example, in different embodiments, in step (a), the heating rate can be 0.2°C / min, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, etc.; in step (a), the cooling rate can be 0.1°C / min, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, etc.

[0051] In a specific embodiment of the present invention, during the upsetting process of the multi-directional forging, multiple down-upsetting operations are performed until a preset deformation amount is reached; wherein each down-upsetting operation is 50 to 80 mm, and there is a pause of 4 to 8 seconds between two adjacent down-upsetting operations.

[0052] For example, in different embodiments, the amount of each downsetting can be 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, etc., until the upsetting deformation reaches 25%~55%; the interval between two adjacent downsetting operations can be 4s, 5s, 6s, 7s, 8s, etc.

[0053] The present invention achieves a more uniform temperature and strain field in the billet during the reforging process by performing three or more reversal forging cycles, controlling the deformation during upsetting and drawing, the amount of reduction during each cycle, and the pause time after each cycle. This results in a more uniform and fine grain structure. The upsetting and drawing operations further prevent temperature rise during the forging process, which can lead to grain growth and even localized overheating or burning.

[0054] In a specific embodiment of the present invention, the punching process includes a punch having a diameter of 185 to 250 mm and a conical outer surface with an angle of 2 to 3 degrees. The small end of the punch is pressed into the blank to a depth of 2 / 3 to 3 / 4 of the blank's height. The blank with the punch is then turned over and placed into a punching die. The large end of a punch of the same size is then aligned and pressed into the blank to remove the core material.

[0055] In a specific embodiment of the present invention, during the pre-rolling, the rolling deformation is 30% to 60%. During the pre-rolling process, the height of the blank in the axial direction does not decrease.

[0056] For example, in different embodiments, during the pre-rolling, the rolling deformation can be 30%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 55%, 60%, etc.

[0057] In practice, pre-rolling is performed using a horizontal radial-axial ring rolling mill, with dimensions of φD1 × φd1 × H1 maintained constant at H1 between the upper and lower tapered rollers. After pre-rolling, a hydraulic press is used to flatten the billet from height H1 to height H2. The height difference between H1 and H2 ranges from 10 to 80 mm, for example, 15 to 60 mm.

[0058] In a specific embodiment of the present invention, during the roll forming, the rolling deformation is 35% to 60%. During the roll forming, the height of the blank is reduced by 4 to 8 mm before and after rolling.

[0059] For example, in different embodiments, during the roll forming, the rolling deformation amount can be 35%, 38%, 40%, 42%, 45%, 48%, 50%, 55%, 60%, etc.

[0060] In actual operation, a horizontal radial-axial ring rolling mill is used for the rolling forming. Before and after rolling, the distance between the upper and lower tapered rollers is reduced by 4 to 8 mm, that is, 4 mm ≤ H2 - H3 ≤ 8 mm.

[0061] In a specific embodiment of the present invention, the two-stage solution treatment comprises: keeping the ring blank at 465-470° C. for 4-6 hours, then keeping it at 475-482° C. for 6-10 hours, and water cooling.

[0062] For example, in different embodiments, the two-stage solution treatment may include: the ring blank is kept at a temperature of 465°C, 466°C, 467°C, 468°C, 469°C or 470°C, etc. for 4h, 5h or 6h, etc., and then kept at a temperature of 475°C, 476°C, 477°C, 478°C, 479°C, 480°C, 481°C or 482°C, etc. for 6h, 7h, 8h, 9h or 10h, etc.

[0063] In actual operation, during the double-stage solution treatment, the heating rate from 465-470° C. to 475-482° C. can be 0.2-3° C. / min.

[0064] For example, in different embodiments, during the double-stage solution treatment, the heating rate may be 0.2°C / min, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, and the like.

[0065] In a specific embodiment of the present invention, the transfer time of the ring billet out of the furnace is ≤10s; in the water cooling, the water temperature is 35-65°C, and the cooling time in water is 5-30min.

[0066] For example, in different embodiments, the water temperature of the water cooling can be 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, etc.; the cooling time in water can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0067] The two-stage solution treatment of the present invention involves first performing a low-temperature solution treatment to allow the low-melting-point precipitate phase to fully dissolve into the solid solution, and then performing a high-temperature solution treatment to allow the higher-melting-point precipitate phase to dissolve into the matrix. This avoids the direct high-temperature solution treatment, which would cause the low-melting-point precipitate phase to melt and reduce the alloy strength. The specific two-stage solution heat treatment system allows the solute elements to dissolve more fully into the matrix, forming a supersaturated solid solution. Aging treatment after the two-stage solution treatment allows the precipitation of dispersed strengthening phases, thereby utilizing both solution strengthening and aging strengthening mechanisms to improve the tensile strength of the forging.

[0068] In a specific embodiment of the present invention, the cold bulging amount of the cold bulging is 2% to 4%. The cold bulging amount is calculated based on the inner diameter, and the calculation method of the cold bulging amount is (d3-d2) / d2, that is, 2%≤(d3-d2) / d2≤4%, d2 is the inner diameter of the ring blank after rolling, and d3 is the inner diameter of the ring blank after cold bulging.

[0069] For example, in different embodiments, the cold expansion amount of the cold expansion may be 2%, 2.5%, 3%, 3.5%, 4%, etc.

[0070] In a specific embodiment of the present invention, the cold bulging is completed within 3 hours after the double-stage solution treatment.

[0071] In actual operation, a bulging machine can be used to perform cold bulging according to the size of φD3×φd3×H3.

[0072] In a specific embodiment of the present invention, the artificial aging treatment system is an existing standard two-stage aging system.

[0073] The present invention also provides a 7050 aluminum alloy ring forging manufactured by any one of the above methods.

[0074] In a specific embodiment of the present invention, the tangential, axial and radial tensile properties of the 7050 aluminum alloy ring forging all meet the following requirements: tensile strength ≥560 MPa, yield strength ≥470 MPa, and elongation after fracture ≥5%.

[0075] Examples 1-3

[0076] This embodiment provides a method for manufacturing a 7050 aluminum alloy ring forging, comprising the following steps:

[0077] (1) For 7050 aluminum alloy billets, Figure 1 Heat treatment is carried out according to the heating curve, and then Figure 2 Multi-directional forging is performed in a manner to obtain a blank;

[0078] Specifically, the 7050 aluminum alloy billet can be obtained by casting or extrusion, but is not limited thereto;

[0079] The heating treatment conditions include: using a temperature-charging furnace method, holding the 7050 aluminum alloy billet at 460-470°C for 8-10 hours, then heating it to 475-482°C at a heating rate of 0.2-5°C / min (e.g., 0.3°C / min) and holding it for 4-5 hours, then cooling it to 420-440°C at a cooling rate of 0.1-3°C / min (e.g., 1.5°C / min) and holding it for 3-5 hours, and then taking it out of the furnace for multi-directional forging;

[0080] Multi-directional forging involves first drawing the heat-treated billet in the axial direction and then upsetting it with multiple down-upsetting passes; then drawing it in the radial direction and upsetting it with multiple down-upsetting passes; then drawing it in a radial direction perpendicular to the radial direction and upsetting it with multiple down-upsetting passes; and finally drawing it in the axial direction and shaping it to obtain the billet. The drawing deformation in each direction is controlled between 25% and 60%, and the upsetting deformation in each direction is controlled between 25% and 55%. During the upsetting process, each down-upsetting pass is 50 to 80 mm, followed by a pause of 4 to 8 seconds before the next down-upping pass, until the upsetting deformation reaches 25% to 55%. During the forging process, the final forging temperature is ≥360°C. The directions can be marked before upsetting and drawing for ease of operation.

[0081] (2) punching the blank obtained in step (1) to obtain a ring blank;

[0082] Specifically, the punching includes: selecting a punch with a large head diameter of φ185~φ250mm when punching, and the outer surface of the punch is a conical surface with an angle of 2°~3°, first pressing the small end of the punch into the blank, and the pressing depth is 2 / 3~3 / 4 of the blank height, turning the blank with the punch over and placing it on the punching die, aligning the large head end of the punch of the same size and pressing it into the blank, punching out the punching core material, and obtaining a ring-shaped blank.

[0083] (3) The ring blank obtained in step (2) is subjected to a heat treatment at 420-440° C. and then pre-rolled; and then subjected to a heat treatment at 420-440° C. and then rolled to obtain a ring blank;

[0084] Specifically, the pre-rolling includes: using a horizontal radial-axial ring rolling mill to pre-roll the ring according to the size of φD1×φd1×H1, during which the distance between the upper and lower tapered rollers is always kept constant at H1, and the pre-rolling deformation is 30% to 60%; after pre-rolling, a hydraulic press is used to flatten the end surface of the ring blank from the height H1 to H2;

[0085] The rolling forming includes: using a horizontal radial-axial ring rolling mill to perform rolling forming according to the size of φD2×φd2×H3. Before and after rolling, the distance between the upper and lower cone rollers is reduced by 4~8mm, that is, 4mm≤H2-H3≤8mm, and the deformation of the rolling forming is 35%~60%.

[0086] (4) The ring blank obtained in step (3) is Figure 3 The heating curve is used for double-stage solution treatment;

[0087] Specifically, the two-stage solution treatment includes: adopting the temperature-charging furnace method, keeping the ring blank at 465~470℃ for 4~6h, then heating it to 475~482℃ at a heating rate of 0.2~3℃ / min (such as 2℃ / min), keeping it at this temperature for 6~10h, and then water-cooling it; the transfer time of the ring blank out of the furnace is ≤10s, the water temperature of the water cooling is controlled at 35~65℃, and the cooling time of the ring blank in water is 5~30min.

[0088] (5) using a bulging machine to perform cold bulging treatment on the ring blank obtained in step (4) according to the size of φD3×φd3×H3 to obtain a forging;

[0089] Specifically, the cold bulging is completed within 3 hours after the solution treatment in step (4), and the cold bulging amount is calculated based on the inner diameter (d3-d2) / d2, which is 2%≤(d3-d2) / d2≤4%.

[0090] (6) The forging obtained in step (5) is Figure 4 Artificial aging treatment is carried out using a heating curve (standard two-stage aging system).

[0091] According to the above operation and referring to the specific parameter conditions in Table 1, ring forgings of different sizes were obtained.

[0092] Table 1 Parameter conditions of different embodiments

[0093]

[0094] Comparative Example 1

[0095] Comparative Example 1 refers to the manufacturing method of Example 1, except that:

[0096] The heating treatment conditions of step (1) are different: the heating treatment conditions of comparative example 1 include: adopting the temperature-loading furnace method, first heating the heating furnace to 430~435℃, keeping it warm for 0.5h to make the furnace temperature uniform, and then loading the billet into the furnace. When the temperature of the heating furnace returns to 430~435℃ again, start timing, keep it warm for 6.5h, and then take out the billet and start forging.

[0097] Step (2) is different from Example 1. In Comparative Example 1, the blank is directly upset and punched during forging.

[0098] Step (3) pre-rolling and rolling forming are the same as those in Example 1.

[0099] The solution treatment system in step (4) is different from that in Example 1. The solution treatment in Comparative Example 1 adopts a conventional standard single-stage solution treatment system, specifically, a temperature-based furnace loading method is adopted. The heating furnace is first heated to 478~479℃, and kept warm for 0.5h to make the furnace temperature uniform. Then the billet is loaded into the furnace. When the temperature of the heating furnace returns to 478~479℃ again, the timing is started, and the temperature is kept warm for 10h. Then the billet is taken out of the furnace and water-cooled. The water temperature is 40~45℃; the cooling time is 15min.

[0100] Comparative Example 2

[0101] Comparative Example 2 refers to the manufacturing method of Example 1, except that:

[0102] The heating treatment conditions of step (1) are different: the heating treatment conditions of comparative example 1 include: adopting the temperature-loading furnace method, first heating the heating furnace to 430~435℃, keeping it warm for 0.5h to make the furnace temperature uniform, and then loading the billet into the furnace. When the temperature of the heating furnace returns to 430~435℃ again, start timing, keep it warm for 7h, and then take out the billet and start forging.

[0103] Experimental example

[0104] In order to compare and illustrate the performance of the 7050 aluminum alloy ring forgings obtained in different embodiments and comparative examples, the tensile properties of the 7050 aluminum alloy ring forgings obtained in different embodiments and comparative examples were tested. The testing method was based on GB / T 16865. The specific test results are shown in Table 2.

[0105] Table 2 Tensile properties test results of different 7050 aluminum alloy ring forgings

[0106]

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. 7050 aluminum alloy ring forging manufacturing method, characterized in that, The steps include: (a) heating a 7050 aluminum alloy billet and then performing multidirectional forging to obtain a billet; the heating treatment comprising: maintaining the billet at 460-470° C. for 8-10 hours, then maintaining the billet at 475-482° C. for 4-5 hours, and then maintaining the billet at 420-442° C. for 3-5 hours; (b) punching the blank to obtain a ring blank; heating the ring blank at 420-440° C. and then pre-rolling the ring blank; and then heating the pre-rolled blank at 420-440° C. and then rolling the pre-rolled blank to obtain a ring blank; (c) subjecting the ring blank obtained in step (b) to a two-stage solution treatment, followed by cold bulging, and then to an artificial aging treatment; the artificial aging treatment being a two-stage aging treatment; The multi-directional forging includes: performing at least one stretching and upsetting along the axial direction, one radial direction, and another radial direction of the bar blank, and then stretching along the axial direction to obtain a blank; the deformation amount of upsetting in each direction is 25% to 55%, and the deformation amount of stretching in each direction is 25% to 60%; the one radial direction and the other radial direction are perpendicular to each other; the initial forging temperature of the multi-directional forging is 400 to 440°C, and the final forging temperature is ≥360°C; The two-stage solution treatment comprises: the ring blank is kept at 465-470°C for 4-6 hours, then kept at 475-482°C for 6-10 hours, and water-cooled; During the pre-rolling process, the rolling deformation is 30% to 60%, and the height of the ring blank in the axial direction does not decrease; during the rolling forming, the rolling deformation is 35% to 60%, and the height of the blank decreases by 4 to 8 mm before and after rolling.

2. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 1, wherein: During the upsetting process of the multi-directional forging, multiple down-upsetting operations are performed until a preset deformation amount is reached; wherein each down-upsetting operation is 50 to 80 mm, and a pause of 4 to 8 seconds is performed between two adjacent down-upsetting operations.

3. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 1, wherein: During the two-stage solution treatment, the furnace transfer time of the ring blank is ≤10s.

4. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 1, wherein: In the water cooling, the water temperature is 35-65°C.

5. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 4, wherein: In the water cooling, the cooling time in water is 5 to 30 minutes.

6. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 1, wherein: The cold expansion amount of the cold expansion is 2% to 4%.

7. The method for manufacturing a 7050 aluminum alloy ring forging according to claim 1, wherein: The cold bulging is completed within 3 hours after the double-stage solution treatment.

8. A 7050 aluminum alloy ring forging manufactured by the method for manufacturing a 7050 aluminum alloy ring forging according to any one of claims 1 to 7.

9. The 7050 aluminum alloy ring forging according to claim 8, characterized in that: The tangential, axial and radial tensile properties of the 7050 aluminum alloy ring forging meet the following requirements: tensile strength ≥560 MPa, yield strength ≥470 MPa, and elongation after fracture ≥5%.

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