A method for preparing high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use

Abstract

The present invention discloses a method for preparing high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use, comprising the following steps: step S1, batching; step S2, smelting and casting; step S3, soaking; step S4, machining and milling; step S5, preheating the ingot; step S6, hot rough rolling and hot finish rolling; step S7, cross-cutting; step S8, cold deformation strengthening; and step S9, inspection and packaging. The present method significantly improves the mechanical properties of 5A06 hot-rolled plate. The method shortens the production process and eliminates the need for intermediate annealing or stabilization annealing, significantly improving production efficiency and effectively reducing production costs compared to existing technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy plate processing, and in particular to a method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use. Background Art

[0002] 5A06 is a typical high-Mg alloy in the 5xxx series of aluminum alloys. It has the characteristics of light weight, high strength, and high rigidity. It also has excellent welding performance, good corrosion resistance and strong oxidation resistance. It is widely used in the aerospace field such as manufacturing spacecraft structures, missile parts and satellite components.

[0003] 5A06-H34 sheet material primarily achieves mechanical strength through cold working deformation strengthening, making it a preferred material for missile casings due to its higher strength. GJB 390A-2008, "Specification for Aluminum Alloy Sheet for Aerospace Applications," stipulates that 5A06-H34 sheet material in the thickness range of >4.0 to 13.0 mm must have a tensile strength of ≥375 MPa, a yield strength of ≥285 MPa, and an elongation of ≥8%. Furthermore, the standard stipulates that upon retesting within three months of leaving the factory, the yield strength must be ≥265 MPa. This indicates that 5A06-H34 sheet material is subject to a strength degradation effect. If the material's mechanical strength is insufficient upon leaving the factory, it risks failing performance during retesting by the OEM, seriously impacting its subsequent engineering applications. Therefore, the preparation of 5A06-H34 sheet material is extremely challenging.

[0004] For 5A06-H34 sheets with a thickness of less than 4mm, industrial production can directly design the reduction of each cold rolling pass to achieve an increase in the material's mechanical strength. In the publicly reported invention patent ZL201410457425.5, "A Method for Producing High-Magnesium Aluminum Alloy Sheets," by controlling the final rolling temperature within the range of 330-380°C, the sheet is fully annealed, eliminating the need for intermediate annealing and reducing the tendency of the sheet to crack during hot rolling. This technical solution primarily utilizes cold rolling deformation and stabilization annealing processes to enhance the sheet's strength, producing 5A06-H34 sheets with a thickness of 1-4mm, achieving a tensile strength of 380-460MPa, a yield strength of 280-350MPa, and an elongation of 12-18%.

[0005] For 5A06-H34 plates with thicknesses greater than 4.0 to 13.0 mm, the mechanical strength cannot be directly improved by cold rolling deformation on a cold rolling mill due to their greater thickness. Therefore, industrial production requires the use of a hot finishing rolling + cold deformation production method. The publicly reported scientific paper "Research on the Production Process of 5A06-H34 Thick Plate" reported on the production process of 5.0 mm thick plates. The paper mainly used hot rolling + secondary cold rolling + stabilization annealing process to control the performance of 5A06-H34 plates. However, this process is long and time-consuming, and the stabilization annealing increases production costs.

[0006] The technical disadvantages of existing 5A06-H34 plates are as follows: (1) Cold-rolled plates with a thickness of less than 4 mm are subjected to controlled high-temperature rolling during the hot rolling stage, only to reduce the tendency of 5A06 to crack during the hot rolling stage, but it is not shown whether controlled high-temperature rolling is helpful in improving the strength of the material; (2) Whether it is finished rolled plates with a thickness of more than 4.0 to 13.0 mm or cold rolled plates with a thickness of less than 4 mm, a stabilized annealing process is used to control the final strength of the plates, but the stabilized annealing process will inevitably increase production costs; (3) Finished rolled plates with a thickness of more than 4.0 to 13.0 mm adopt a process of hot rolling + cross-cutting + intermediate annealing + secondary cold rolling, especially the deformation of the secondary cold rolling reaches an astonishing 25 to 50%. This process not only requires an additional intermediate annealing process to soften the hardness of the alloy, increasing production costs, but the large cold deformation will also reduce the service life of the rolling mill working rolls.

[0007] In view of this, the present invention proposes a method for preparing high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use. The method provides several technical solutions for significantly improving the mechanical strength of 5A06 hot-rolled plate, shortens the production process, reduces the stabilization annealing process, and further improves production efficiency and saves production costs. At the same time, the product performance meets the GJB 390A-2008 "Specifications for Aluminum Alloy Plates for Aerospace Use". Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for preparing high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use. By strictly controlling the final rolling temperature of the 5A06 hot-rolled plate, adopting key technologies such as cold pressing with a small deformation amount on a hot rolling mill, multi-step speed and rate controlled pre-stretching or single-step yield controlled pre-stretching, a large number of dislocations are introduced into the alloy, thereby achieving a significant improvement in the mechanical properties of the 5A06 hot-rolled plate. The production process of the present invention is short and does not require intermediate annealing / stabilization annealing and other heat treatment processes. Compared with the existing technology, the production efficiency is greatly improved while the production cost is reduced.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use, comprising the following steps:

[0010] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.5-0.8%, Mg 5.8-6.8%, Zn ≤ 0.20%, Ti 0.02-0.10%, Be 0.0001-0.0050%, and the rest are Al and some unavoidable impurity elements;

[0011] Step S2, smelting and casting: adding some aluminum ingots or return materials into the smelting furnace, setting the furnace gas temperature not exceeding 1100°C, melting the aluminum ingots or return materials, adding the master alloy, starting electromagnetic stirring after the master alloy is completely melted, and then adding the remaining aluminum ingots or return materials. After furnace refining, online refining, and online filtration, casting production begins when the aluminum melt temperature reaches 700-720°C to obtain 5A06 ingots;

[0012] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 500-520°C, a holding time of 10-14 hours, a heating rate of 55-65°C / h, and air cooling after soaking to obtain a soaked ingot;

[0013] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 100-200 mm of the top of the ingot and 200-400 mm of the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 10-20 mm of the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0014] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 500-520° C., and the holding time is 5-30 hours to obtain the preheated ingot;

[0015] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 25 to 30 mm and a transfer billet thickness of 15 to 25 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265 to 275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0016] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0017] Step S8, cold deformation strengthening:

[0018] Cold deformation strengthening method 1: hot rolling mill cold pressing + stretching straightening: the 5A06 plate cut into double-length plates is subjected to a small deformation cold pressing on a hot roughing mill to the finished thickness, with a total deformation of 3-9% and one cold pressing pass; then, stretching and straightening are performed on a stretching machine. After stretching, the shape and position tolerances of the plate meet the requirements of GJB 390A-2008 "Specifications for Aluminum Alloy Plates for Aerospace Use", thus obtaining a plate strengthened by cold deformation;

[0019] Cold deformation strengthening method 2: multi-step speed and rate controlled pre-stretching: the 5A06 plate cut into multiple lengths is placed in a stretching machine. Before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 4-6%, the stretching rate of each step is designed to be 1%, and the stretching rate is set to 1.4-1.6 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time after each stretching step is completed to obtain the plate after cold deformation strengthening.

[0020] Cold deformation strengthening method three, single-step controlled yield pre-stretching: the 5A06 plate cut into multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the plate, and the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the plate is stretched in one step until the real-time yield strength reaches 350-360 MPa, and the stretching rate is set to 1.4-1.6 mm / min to obtain the plate after cold deformation strengthening. After the stretching is completed, the actual stretching rate of the nine one-meter lines is measured.

[0021] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications, and packaging and shipping the finished products that have passed the inspection.

[0022] Furthermore, the composition and weight ratio of the aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate in step S1 are: Si≤0.40%, Fe≤0.40%, Cu≤0.10%, Mn 0.6~0.8%, Mg 6.2~6.8%, Zn≤0.20%, Ti 0.05~0.10%, Be 0.0015~0.0050%, and the rest are Al and some inevitable impurity elements.

[0023] Furthermore, in step S2, half of the aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set not to exceed 1100°C, the aluminum ingots or return materials are melted, the intermediate alloy is added, and electromagnetic stirring is started after the intermediate alloy is completely melted, and the remaining aluminum ingots or return materials are added. After furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710-720°C to obtain 5A06 ingots.

[0024] Furthermore, in step S3, the 5A06 ingot is subjected to homogenization heat treatment, with a soaking temperature of 510-520°C, a holding time of 12-14h, a heating rate of 60°C / h, and is taken out of the furnace and air-cooled after soaking to obtain a soaked ingot.

[0025] Furthermore, in step S6, the preheated ingot is rolled to the transfer billet thickness by hot rough rolling, the single-pass reduction of hot rough rolling is 27 to 30 mm, and the transfer billet thickness is 18 to 22 mm; it is rolled to the cold design thickness by hot finish rolling, the cold thickness is reserved according to the cold working deformation amount of the subsequent process, the hot finish rolling final rolling temperature is strictly controlled to be within the range of 265 to 275°C, and it is cooled to room temperature to obtain 5A06 coil.

[0026] Furthermore, in step S7, the 5A06 coil is fed into the cross-cutting process, and the plate is cut into 3 to 6 times the length according to the length specification of the finished plate and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the cutting amount of the single-length stretching jaws, and obtaining a 5A06 plate with a cross-cut length. In addition, sampling is performed during the cross-cutting process, and the longitudinal tensile properties of the plate are tested in the laboratory, providing an accurate basis for the input of parameters of the pre-stretching control interface in the subsequent process.

[0027] Furthermore, in step S8, the cold deformation strengthening method 1, hot rolling mill cold pressing + stretching straightening: the 5A06 plate that has been cross-cut and cut into multiple-size plates is cold-pressed with a small deformation amount on a hot roughing mill to the finished thickness, with a total deformation amount of 4-6% and one cold pressing pass; then stretching and straightening is performed on a stretching machine, and the form and position tolerances of the plate after stretching meet the requirements of GJB 390A-2008 "Specifications for Aluminum Alloy Plates for Aerospace Use", thereby obtaining a plate that has been cold-deformed and strengthened.

[0028] Furthermore, in step S8, the second cold deformation strengthening method is multi-step speed and rate controlled pre-stretching: the 5A06 plate that is cross-cut and opened in multiple sizes is put into the stretching machine, and before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface; during stretching, the total stretching rate reaches 4 to 6%, the stretching rate of each step is designed to be 1%, the first step stretching rate is set to 1.4 mm / min, the second step stretching rate is set to 1.55 mm / min, the third step stretching rate is set to 1.6 mm / min, and the fourth step to the sixth step stretching rate are set to 1.55 mm / min; the real-time yield strength data of the stretching machine control interface is recorded in real time when each stretching step is completed to obtain the plate after cold deformation strengthening.

[0029] Furthermore, in step S8, the third cold deformation strengthening method is single-step controlled yield pre-stretching: the 5A06 plate that has been cross-cut and opened in multiple sizes is put into a stretching machine. Before stretching, a total of 9 1-meter lines are drawn on the width and length directions of the upper surface of the plate, and the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface; during stretching, the plate is stretched in one step until the real-time yield strength reaches 350-360 MPa, and the stretching rate is set to 1.5 mm / min to obtain the plate after cold deformation strengthening; after stretching, the actual stretching rate of the 9 1-meter lines is measured.

[0030] Furthermore, if the tensile strength of the plate after cold deformation strengthening in step S9 is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength when retested within three months from the date of leaving the factory is ≥265MPa, then the cold deformation strengthened plate tested is judged to be qualified.

[0031] The present invention discloses a method for preparing a high-strength 5A06-H34 aluminum alloy hot-finished plate for aerospace use. The method is mainly developed to address the insufficient mechanical strength of 5A06-H34 hot-finished rolled plates with a thickness of more than 4.0 to 13.0 mm. By strictly controlling the final rolling temperature of the 5A06 hot-finished rolling, adopting key technologies such as cold pressing with a small deformation amount on a hot rolling mill, multi-step speed and rate controlled pre-stretching or single-step yield controlled pre-stretching, a large number of dislocations are introduced into the alloy, ultimately significantly improving the mechanical properties of the 5A06-H34 hot-finished rolled plates. The key points of the method of the present invention are: 1) hot finishing rolling is carried out at a controlled low temperature (265-275°C), and the cold thickness is reserved according to the cold working deformation amount of the subsequent process; 2) the hot rolling mill uses a single pass cold pressing with a small deformation amount (4-6%), without the need for intermediate annealing and stabilization annealing; 3) the stretching machine uses a multi-step rate control (stretching rate of 4-6%) pre-stretching, with a stretching rate of 1% per step, and real-time recording of the yield data achieved when each step of stretching is completed, providing data support for the subsequent single-step rate control pre-stretching; 4) the stretching machine uses a single-step rate control (real-time yield of 350-360MPa) pre-stretching, stopping the single-step stretching when the real-time yield is 350-360MPa, and measuring the actual stretching rate of 9 1-meter wires after stretching, which is mutually verified with the above multi-step rate control and rate control pre-stretching. The method of the present invention can achieve a significant improvement in the mechanical properties of 5A06 hot finishing rolled plate. The production process of the present invention is short, and no heat treatment processes such as intermediate annealing / stabilization annealing are required. Compared with the existing technology, the production efficiency is greatly improved, while the production cost is effectively reduced.

[0032] The present invention provides a method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use. During stretching in step S8, the total stretching rate reaches 4-6%, the stretching rate of each step is designed to be 1%, the stretching rate of the first step is set to 1.4 mm / min, the stretching rate of the second step is set to 1.55 mm / min, the stretching rate of the third step is set to 1.6 mm / min, and the stretching rates of the fourth step to the sixth step are set to 1.55 mm / min; the stretching rate of each step is first controlled to 1%, and then the stretching rate of each step is strictly controlled according to low, medium, high, and medium stretching rates, which can significantly reduce the strength attenuation effect of the 5A06-H34 plate and effectively improve the product stability and qualified rate.

[0033] Figures in the specification

[0034] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0035] The following examples may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

[0036] Example 1: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0037] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0038] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.5%, Mg 5.8%, Zn ≤ 0.20%, Ti 0.02%, Be 0.0001%, and the rest are Al and some unavoidable impurity elements;

[0039] Step S2, smelting and casting: 40 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set not to exceed 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and after the master alloy is completely melted, electromagnetic stirring is started, and the remaining aluminum ingots or return materials are added. After furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 700°C to obtain 5A06 ingots;

[0040] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 500°C, a holding time of 10 hours, a heating rate of 55°C / h, and air cooling after soaking to obtain a soaked ingot;

[0041] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 100 mm of the top of the ingot and 200 mm of the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 10 mm of the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0042] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 500° C., and the holding time is 5 hours to obtain the preheated ingot;

[0043] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 25 mm and a transfer billet thickness of 15 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0044] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0045] Step S8, cold deformation strengthening:

[0046] Hot rolling mill cold pressing + stretching straightening: The 5A06 plate cut to double length is subjected to a small deformation cold pressing on a hot roughing mill to the finished thickness, with a total deformation of 4% and one cold pressing pass; then, it is stretched and straightened on a stretching machine. After stretching, the shape and position tolerances of the plate meet the requirements of GJB 390A-2008 "Specifications for Aluminum Alloy Plates for Aerospace Use", thus obtaining a plate strengthened by cold deformation;

[0047] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0048] Example 2: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0049] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0050] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.8%, Mg 6.8%, Zn ≤ 0.20%, Ti 0.10%, Be 0.0050%, and the rest are Al and some unavoidable impurity elements;

[0051] Step S2, smelting and casting: 60wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 720°C to obtain 5A06 ingots;

[0052] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 520°C, a holding time of 14 hours, a heating rate of 65°C / h, and air cooling after soaking to obtain a soaked ingot;

[0053] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 200 mm of the top of the ingot and 400 mm of the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 20 mm of the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0054] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 520° C., and the heat preservation time is 30 hours to obtain the preheated ingot;

[0055] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 30 mm and a transfer billet thickness of 25 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0056] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0057] Step S8, cold deformation strengthening:

[0058] Multi-step speed and rate controlled pre-stretching: The 5A06 plate cut to multiple lengths is placed in a stretching machine. Before stretching, the thickness, width, length, and yield strength of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 4%, the stretching rate of each step is designed to be 1%, and the stretching rate is set to 1.4 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time after each stretching step is completed to obtain the plate after cold deformation strengthening.

[0059] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0060] Example 3: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0061] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0062] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.8%, Mg 6.8%, Zn ≤ 0.20%, Ti 0.10%, Be 0.0050%, and the rest are Al and some unavoidable impurity elements;

[0063] Step S2, smelting and casting: 60wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 720°C to obtain 5A06 ingots;

[0064] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 520° C., a holding time of 14 h, a heating rate of 62° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0065] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 200 mm of the top of the ingot and 400 mm of the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 20 mm of the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0066] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 520° C., and the heat preservation time is 30 hours to obtain the preheated ingot;

[0067] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 30 mm and a transfer billet thickness of 25 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0068] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0069] Step S8, cold deformation strengthening:

[0070] Multi-step speed and rate controlled pre-stretching: The 5A06 plate cut into multiple lengths is fed into a stretching machine. Before stretching, the thickness, width, length, and yield strength of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 6%, the stretching rate of each step is designed to be 1%, and the stretching rate is set to 1.6 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time after each stretching step is completed to obtain the plate after cold deformation strengthening.

[0071] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0072] Example 4: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0073] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0074] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0075] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0076] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0077] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0078] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0079] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 27 mm and a transfer billet thickness of 18 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0080] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0081] Step S8, cold deformation strengthening:

[0082] Multi-step speed and rate controlled pre-stretching: The 5A06 plate cut to multiple lengths is placed in a stretching machine. Before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 4%, and the stretching rate of each step is designed to be 1%. The first step stretching rate is set to 1.4 mm / min, the second step stretching rate is set to 1.55 mm / min, the third step stretching rate is set to 1.6 mm / min, and the fourth step stretching rate is set to 1.55 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time upon completion of each stretching step to obtain the plate after cold deformation strengthening.

[0083] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0084] Example 5: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0085] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0086] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0087] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0088] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0089] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0090] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0091] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 27 mm and a transfer billet thickness of 18 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0092] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0093] Step S8, cold deformation strengthening:

[0094] Multi-step speed and rate controlled pre-stretching: The 5A06 plate cut into multiple lengths is placed in a stretching machine. Before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 6%, and the stretching rate of each step is designed to be 1%. The first step stretching rate is set to 1.4 mm / min, the second step stretching rate is set to 1.55 mm / min, the third step stretching rate is set to 1.6 mm / min, and the fourth to sixth steps stretching rate are set to 1.55 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time after each stretching step is completed to obtain the plate after cold deformation strengthening.

[0095] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0096] Example 6: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm respectively

[0097] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0098] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0099] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0100] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0101] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0102] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0103] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 27 mm and a transfer billet thickness of 18 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0104] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0105] Step S8, cold deformation strengthening:

[0106] Single-step controlled yield pre-stretching: The 5A06 sheet material cut into multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the sheet material. The thickness, width, length, and yield strength information of the sheet material are accurately input into the stretching machine control interface. During stretching, the sheet material is stretched in one step until the real-time yield strength reaches 350 MPa. The stretching rate is set to 1.4 mm / min to obtain a sheet material strengthened by cold deformation. After the stretching is completed, the actual stretch rate of the nine one-meter lines is measured.

[0107] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0108] Example 7: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm

[0109] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0110] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0111] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0112] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0113] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0114] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0115] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 27 mm and a transfer billet thickness of 18 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0116] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0117] Step S8, cold deformation strengthening:

[0118] Single-step controlled yield pre-stretching: The 5A06 sheet material cut to multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the sheet material. The thickness, width, length, and yield strength information of the sheet material are accurately input into the stretching machine control interface. During stretching, the sheet material is stretched in one step until the real-time yield strength reaches 360 MPa. The stretching rate is set to 1.6 mm / min to obtain a sheet material strengthened by cold deformation. After the stretching is completed, the actual stretching rate of the nine one-meter lines is measured.

[0119] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0120] Example 8: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm respectively

[0121] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0122] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0123] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0124] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0125] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0126] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0127] Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 27 mm and a transfer billet thickness of 18 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil;

[0128] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0129] Step S8, cold deformation strengthening:

[0130] Single-step controlled yield pre-stretching: The 5A06 sheet material cut to multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the sheet material. The thickness, width, length, and yield strength information of the sheet material are accurately input into the stretching machine control interface. During stretching, the sheet material is stretched in one step until the real-time yield strength reaches 355 MPa. The stretching rate is set to 1.5 mm / min to obtain the sheet material after cold deformation strengthening. After the stretching is completed, the actual stretch rate of the nine one-meter lines is measured.

[0131] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0132] Comparative Example 1: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm respectively

[0133] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0134] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0135] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0136] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0137] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0138] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0139] Step S6, hot rough rolling + high-temperature hot rolling: the preheated ingot is rolled to the transfer billet thickness by hot rough rolling, the hot rough rolling single pass reduction is 27 mm, and the transfer billet thickness is 18 mm; the ingot is rolled to the cold design thickness by high-temperature hot rolling, the cold thickness is reserved according to the cold working deformation amount of the subsequent process, the high-temperature hot rolling finishing temperature is controlled to be within the range of 330-380° C., and the ingot is cooled to room temperature to obtain 5A06 coil;

[0140] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0141] Step S8, cold deformation strengthening:

[0142] Hot rolling mill cold pressing + stretching straightening: The 5A06 plate cut to double length is cold-pressed on a hot roughing mill with a small deformation to the finished thickness, with a total deformation of 6% and one cold-pressing pass; then, it is stretched and straightened on a stretching machine. After stretching, the shape and position tolerances of the plate meet the requirements of GJB 390A-2008 "Specifications for Aluminum Alloy Plates for Aerospace Use", thus obtaining a plate strengthened by cold deformation;

[0143] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0144] Comparative Example 2: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm respectively

[0145] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0146] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0147] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0148] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0149] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0150] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0151] Step S6, hot rough rolling + high-temperature hot rolling: the preheated ingot is rolled to the transfer billet thickness by hot rough rolling, the hot rough rolling single pass reduction is 27 mm, and the transfer billet thickness is 18 mm; the ingot is rolled to the cold design thickness by high-temperature hot rolling, the cold thickness is reserved according to the cold working deformation amount of the subsequent process, the high-temperature hot rolling finishing temperature is controlled to be within the range of 330-380° C., and the ingot is cooled to room temperature to obtain 5A06 coil;

[0152] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0153] Step S8, cold deformation strengthening:

[0154] Multi-step speed and rate controlled pre-stretching: The 5A06 plate cut into multiple lengths is fed into a stretching machine. Before stretching, the thickness, width, length, and yield strength of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 6%, the stretching rate of each step is designed to be 1%, and the stretching rate is set to 1.6 mm / min. The real-time yield strength data of the stretching machine control interface is recorded in real time after each stretching step is completed to obtain the plate after cold deformation strengthening.

[0155] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0156] Comparative Example 3: Production of 5A06-H34 sheets with thicknesses of 9.5 mm and 12.5 mm respectively

[0157] A method for preparing aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate comprises the following steps:

[0158] Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.6%, Mg 6.2%, Zn ≤ 0.20%, Ti 0.05%, Be 0.0015%, and the rest are Al and some unavoidable impurity elements;

[0159] Step S2, smelting and casting: 50 wt% aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set to no more than 1100°C, the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710°C to obtain 5A06 ingots;

[0160] Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 510° C., a holding time of 12 h, a heating rate of 60° C. / h, and air cooling after soaking to obtain a soaked ingot;

[0161] Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 150 mm from the top of the ingot and 300 mm from the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 15 mm from the large and small surfaces of the ingot, to obtain the ingot after machining and milling;

[0162] Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 510° C., and the holding time is 8 hours to obtain the preheated ingot;

[0163] Step S6, hot rough rolling + high-temperature hot rolling: the preheated ingot is rolled to the transfer billet thickness by hot rough rolling, the hot rough rolling single pass reduction is 27 mm, and the transfer billet thickness is 18 mm; the ingot is rolled to the cold design thickness by high-temperature hot rolling, the cold thickness is reserved according to the cold working deformation amount of the subsequent process, the high-temperature hot rolling finishing temperature is controlled to be within the range of 330-380° C., and the ingot is cooled to room temperature to obtain 5A06 coil;

[0164] Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process.

[0165] Step S8, cold deformation strengthening:

[0166] Single-step controlled yield pre-stretching: The 5A06 sheet material cut to multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the sheet material. The thickness, width, length, and yield strength information of the sheet material are accurately input into the stretching machine control interface. During stretching, the sheet material is stretched in one step until the real-time yield strength reaches 360 MPa. The stretching rate is set to 1.6 mm / min to obtain a sheet material strengthened by cold deformation. After the stretching is completed, the actual stretching rate of the nine one-meter lines is measured.

[0167] Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications. If the tensile strength of the cold-deformed and strengthened plates is ≥375MPa, the yield strength is ≥285MPa, and the elongation is ≥8%, and the yield strength is ≥265MPa when re-tested within three months from the date of leaving the factory, the cold-deformed and strengthened plates are judged to be qualified; the qualified finished products are packaged and shipped.

[0168] The various properties of the plates prepared in Examples 1-8 and Comparative Examples 1-3 were tested, and the test results are shown in Tables 1 and 2 below.

[0169] Table 1 Performance parameters of 5A06-H34 sheet with a thickness of 9.5 mm

[0170] Serial number Tensile strength (MPa) Yield strength (MPa) Elongation (%) Yield strength at the time of retest three months after leaving the factory (MPa) Yield strength at the time of retest six months after leaving the factory (MPa) Plate strength anti-attenuation effect Acceptance value ≥375 ≥285 ≥8 ≥265 / / Example 1 395-400 285-287 17.5-20 265-269 237-248 Poor Example 2 400-401 287-289 16.5-16.5 275-275 260-265 good Example 3 413-413 331-335 13-16.5 317-320 302-304 good Example 4 398-402 289-290 17-19.5 285-287 280-284 powerful Example 5 413-414 331-341 16.5-17.5 328-338 326-334 powerful Example 6 400-402 285-288 18.5-18.5 273-275 265-269 good Example 7 405-410 292-298 16.5-17 285-287 275-277 good Example 8 404-406 287-291 17-18 277-283 266-273 good Comparative Example 1 392-395 268-270 9.5-13.5 Unqualified / / Comparative Example 2 390-394 259-264 15.5-17 Unqualified / / Comparative Example 3 386-391 252-256 17.5-18.5 Unqualified / /

[0171] Table 2 Performance parameters of 5A06-H34 sheet with a thickness of 12.5 mm

[0172] Serial number Tensile strength (MPa) Yield strength (MPa) Elongation (%) Yield strength at the time of retest three months after leaving the factory (MPa) Yield strength at the time of retest six months after leaving the factory (MPa) Plate strength anti-attenuation effect Acceptance value ≥375 ≥285 ≥8 ≥265 / / Example 1 405-408 286-289 19.5-20 269-271 239-243 Poor Example 2 406-407 287-288 19-21 273-278 253-257 good Example 3 422-428 314-318 21.5-21.5 302-302 282-284 good Example 4 400-406 290-294 19-20 288-290 284-288 powerful Example 5 417-424 327-330 18-18.5 318-326 313-320 powerful Example 6 413-416 300-307 16.5-18 286-290 272-275 good Example 7 422-427 311-315 18-18 295-302 283-290 good Example 8 416-416 311-315 16-19 294-296 281-286 good Comparative Example 1 391-396 269-271 22-23 Unqualified / / Comparative Example 2 386-391 253-257 23.5-24.5 Unqualified / / Comparative Example 3 375-376 232-239 25-26 Unqualified / /

[0173] It can be seen from the above test results that the preparation method of the high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use in the present invention is mainly developed to address the insufficient mechanical strength of 5A06-H34 hot-rolled plates with a thickness of more than 4.0 to 13.0 mm. By strictly controlling the final rolling temperature of the 5A06 hot-rolled plate, using a hot rolling mill with a small deformation amount of cold pressing, multi-step speed and rate controlled pre-stretching or single-step yield controlled pre-stretching and other key technologies, a large number of dislocations are introduced into the alloy, and ultimately the mechanical properties of the 5A06-H34 hot-rolled plate are significantly improved. The key points of the method of the present invention are: 1) hot finishing rolling is carried out at a controlled low temperature (265-275°C), and the cold thickness is reserved according to the cold working deformation of the subsequent process; 2) the hot rolling mill uses a single pass of small deformation cold pressing (4-6%), without the need for intermediate annealing and stabilization annealing; 3) the stretching machine uses a multi-step rate control (stretching rate 4-6%) for pre-stretching, with a stretching rate of 1% per step, and real-time recording of the real-time yield data when each step of stretching is completed, providing data support for the subsequent single-step rate control pre-stretching; 4) the stretching machine uses a single-step rate control (real-time yield 350-360MPa) for pre-stretching, and stops when the single-step stretching reaches a real-time yield of 350-360MPa. After stretching, the actual stretching rates of 9 1-meter lines are measured, which are mutually verified with the above multi-step rate control and rate control pre-stretching; the mechanical properties of 5A06 hot finishing plate can be achieved by using the method of the present invention. The present invention has a significant improvement in energy efficiency. The production process is short and does not require intermediate annealing / stabilization annealing and other heat treatment processes. Compared with the existing technology, the production efficiency is greatly improved, and the production cost is effectively reduced. During stretching in step S8, the total stretching rate reaches 4-6%, the stretching rate of each step is designed to be 1%, the first step stretching rate is set to 1.4mm / min, the second step stretching rate is set to 1.55mm / min, the third step stretching rate is set to 1.6mm / min, and the fourth step stretching-the sixth step stretching rate is set to 1.55mm / min. First, the stretching rate of each step is controlled at 1%, and then the stretching rate of each step is strictly controlled according to the low, medium, high and medium stretching rates. This can significantly reduce the strength attenuation effect of 5A06-H34 plate and effectively improve product stability and qualified rate.

[0174] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for preparing high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use, characterized in that: The following steps are involved: Step S1, ingredients: The composition and weight ratio of aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate are as follows: Si ≤ 0.40%, Fe ≤ 0.40%, Cu ≤ 0.10%, Mn 0.5-0.8%, Mg 5.8-6.8%, Zn ≤ 0.20%, Ti 0.02-0.10%, Be 0.0001-0.0050%, and the rest are Al and some unavoidable impurity elements; Step S2, smelting and casting: adding some aluminum ingots or return materials into the smelting furnace, setting the furnace gas temperature not exceeding 1100°C, melting the aluminum ingots or return materials, adding the master alloy, starting electromagnetic stirring after the master alloy is completely melted, and then adding the remaining aluminum ingots or return materials. After furnace refining, online refining, and online filtration, casting production begins when the aluminum melt temperature reaches 700-720°C to obtain 5A06 ingots; Step S3, soaking: performing a homogenization heat treatment on the 5A06 ingot at a soaking temperature of 500-520°C, a holding time of 10-14 hours, a heating rate of 55-65°C / h, and air cooling after soaking to obtain a soaked ingot; Step S4, machining and milling: cutting the head and tail of the soaked ingot, sawing off 100-200 mm of the top of the ingot and 200-400 mm of the bottom of the ingot respectively; then milling the ingot on a milling machine, milling off 10-20 mm of the large and small surfaces of the ingot, to obtain the ingot after machining and milling; Step S5, ingot preheating: preheating the ingot after the machining and milling, the preheating temperature is 500-520° C., and the holding time is 5-30 hours to obtain the preheated ingot; Step S6, hot rough rolling + hot finish rolling: The preheated ingot is rolled to the transfer billet thickness by hot rough rolling, with a single pass reduction of 25 to 30 mm and a transfer billet thickness of 15 to 25 mm; the ingot is rolled to the cold design thickness by hot finish rolling, with the cold thickness reserved according to the cold working deformation amount of the subsequent process, and the hot finish rolling finishing temperature is strictly controlled to be within the range of 265 to 275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil; Step S7, cross-cutting: The 5A06 coil is fed into the cross-cutting process, where the sheet is cut into multiple lengths according to the length specifications of the finished sheet and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the removal of the single-length stretching jaws, and obtaining 5A06 sheets cut into multiple lengths. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the sheet are tested in the laboratory to provide an accurate basis for the input of parameters for the pre-stretching control interface in the subsequent process. Step S8, cold deformation strengthening: Cold deformation strengthening method 1: multi-step speed and rate controlled pre-stretching: the 5A06 plate cut into multiple lengths is placed in a stretching machine. Before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the total stretching rate reaches 4-6%, the stretching rate of each step is designed to be 1%, and the stretching rate is set to 1.4-1.6 mm / min. After each stretching step is completed, the real-time yield strength data of the stretching machine control interface is recorded in real time to obtain the plate after cold deformation strengthening. Cold deformation strengthening method 2, single-step controlled yield pre-stretching: The 5A06 plate cut into multiple lengths is placed in a stretching machine. Before stretching, nine one-meter lines are drawn on the width and length directions of the upper surface of the plate, and the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface. During stretching, the plate is stretched in one step until the real-time yield strength reaches 350-360 MPa, and the stretching rate is set to 1.4-1.6 mm / min to obtain the plate after cold deformation strengthening. After the stretching is completed, the actual stretching rate of the nine one-meter lines is measured. Step S9, inspection and packaging: sawing and sampling the cold-deformed and strengthened plates according to the finished product specifications, and packaging and shipping the finished products that have passed the inspection.

2. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: The composition and weight ratio of the aerospace high-strength 5A06-H34 aluminum alloy hot-rolled plate in step S1 are: Si≤0.40%, Fe≤0.40%, Cu≤0.10%, Mn 0.6~0.8%, Mg 6.2~6.8%, Zn≤0.20%, Ti0.05~0.10%, Be 0.0015~0.0050%, and the rest are Al and some inevitable impurity elements.

3. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: In step S2, half of the aluminum ingots or return materials are added to the smelting furnace, the furnace gas temperature is set not to exceed 1100° C., the aluminum ingots or return materials are melted, the master alloy is added, and electromagnetic stirring is started after the master alloy is completely melted. The remaining aluminum ingots or return materials are then added, and after furnace refining, online refining, and online filtration, casting production is started when the aluminum melt temperature reaches 710-720° C. to obtain 5A06 ingots.

4. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: In step S3, the 5A06 ingot is subjected to homogenization heat treatment at a soaking temperature of 510-520° C., a holding time of 12-14 h, a heating rate of 60° C. / h, and is taken out of the furnace and air-cooled after soaking to obtain a soaked ingot.

5. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: In step S6, the preheated ingot is rolled to the transfer blank thickness by hot rough rolling, the single-pass reduction of hot rough rolling is 27-30 mm, and the transfer blank thickness is 18-22 mm; and the ingot is rolled to the cold design thickness by hot finish rolling, the cold thickness is reserved according to the cold working deformation amount of the subsequent process, the hot finish rolling final rolling temperature is strictly controlled to be within the range of 265-275° C., and the ingot is cooled to room temperature to obtain a 5A06 coil.

6. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: In step S7, the 5A06 coil is fed into the cross-cutting process, and the plate is cut into 3 to 6 times the length according to the length specification of the finished plate and the maximum stretching stroke of the stretching machine, thereby reducing the geometric waste caused by the cutting amount of the single-length stretching jaws, and obtaining the 5A06 plate with cross-cut length. In addition, samples are taken during the cross-cutting process, and the longitudinal tensile properties of the plate are tested in the laboratory to provide an accurate basis for the input of parameters of the pre-stretching control interface in the subsequent process.

7. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: The cold deformation strengthening method in step S8 is as follows:

1. Multi-step speed-controlled and rate-controlled pre-stretching: the 5A06 plate that has been cross-cut and opened in multiple lengths is put into a stretching machine. Before stretching, the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface; during stretching, the total stretching rate reaches 4-6%, the stretching rate of each step is designed to be 1%, the first step stretching rate is set to 1.4 mm / min, the second step stretching rate is set to 1.55 mm / min, the third step stretching rate is set to 1.6 mm / min, and the fourth step to the sixth step stretching rate are set to 1.55 mm / min; the real-time yield strength data of the stretching machine control interface is recorded in real time when each stretching step is completed to obtain the plate after cold deformation strengthening.

8. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: The second cold deformation strengthening method in step S8 is single-step controlled yield pre-stretching: the 5A06 plate that has been cross-cut and opened in multiple lengths is put into a stretching machine. Before stretching, 9 1-meter lines are drawn on the width and length directions of the upper surface of the plate, and the thickness, width, length, and yield strength information of the plate are accurately input into the stretching machine control interface; during stretching, the plate is stretched in one step until the real-time yield strength reaches 350-360 MPa, and the stretching rate is set to 1.5 mm / min to obtain the plate after cold deformation strengthening; after the stretching is completed, the actual stretching rate of the 9 1-meter lines is measured.

9. The method for preparing a high-strength 5A06-H34 aluminum alloy hot-rolled plate for aerospace use according to claim 1, characterized in that: In step S9, the tensile strength of the cold-deformed strengthened plate is ≥375 MPa, the yield strength is ≥285 MPa, and the elongation is ≥8%. If the yield strength is ≥265 MPa when retested within three months from the date of leaving the factory, the cold-deformed strengthened plate is judged to be qualified.

Images