Cryogenic rolling method of aluminum-zinc-magnesium-copper alloy

Abstract

The invention relates to a deep cooling rolling method of an aluminum-zinc-magnesium-copper alloy, belongs to the technical field of metal material rolling, and solves the problems that a finished product obtained by an existing aluminum-zinc-magnesium-copper alloy preparation method is easy to generate stress concentration, so that cracks are formed at the edge of a material, and material grains are coarse. The deep cooling rolling method of the aluminum-zinc-magnesium-copper alloy comprises the following steps that S1, a deposition blank is prepared; s2, preparing an alloy material plate; s3, carrying out solution treatment; s4, cryogenic heat preservation is conducted; s5, deep cooling rolling is conducted; and S6, natural aging is conducted. The aluminum-zinc-magnesium-copper alloy obtained through the deep cooling rolling method of the aluminum-zinc-magnesium-copper alloy is free of cracks under the large deformation amount, crystal grains are fine to the nanoscale, and the labor cost and the energy consumption cost are saved.

Description

Technical Field

[0001] The invention relates to the technical field of metal material rolling, in particular to a deep cold rolling method of an aluminum-zinc-magnesium-copper alloy. Background Art

[0002] Aluminum-zinc-magnesium-copper alloy has excellent mechanical properties and corrosion resistance, and occupies a pivotal position in key fields such as aerospace, transportation, and high-end equipment manufacturing. For the preparation of aluminum-zinc-magnesium-copper alloy, the existing technology usually adopts hot rolling or room temperature rolling methods. The alloy material obtained by this method is prone to stress concentration, which in turn forms defects such as cracks at the edge of the material. In addition, the material grains obtained by these methods are relatively coarse, which seriously restricts the quality and mechanical properties of the processed products and limits its application in high-precision and high-performance requirements.

[0003] Therefore, in order to solve the problem that the finished products obtained by the existing aluminum-zinc-magnesium-copper alloy preparation method are prone to stress concentration, which leads to cracks at the edge of the material and coarse grains of the material, it is necessary to provide a deep cold rolling method for aluminum-zinc-magnesium-copper alloy. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a deep cold rolling method for aluminum-zinc-magnesium-copper alloy to solve the problem that the finished product obtained by the existing aluminum-zinc-magnesium-copper alloy preparation method is prone to stress concentration, resulting in cracks on the edge of the material and coarse grains of the material.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] An aluminum-zinc-magnesium-copper alloy comprises, by weight percentage, the following chemical components: Zn: 8.8-9.2%, Cu: 2.6-3.0%, Mg: 1.8-2.3%, Zr: 0.10-0.20%, Ti: 0.05-0.10%, Si: ≤0.10%, Fe: ≤0.15%, Mn: ≤0.11%, and the balance is Al.

[0007] Further, for the above aluminum-zinc-magnesium-copper alloy, a deep cold rolling method of the aluminum-zinc-magnesium-copper alloy is provided, comprising the following steps:

[0008] Step S1, preparing a deposition blank, using a spray deposition process to prepare the deposition blank;

[0009] Step S2, preparing an alloy material plate, and hot extruding the deposited blank using a hot extruder;

[0010] Step S3, solution treatment, performing solution treatment on the alloy material plate;

[0011] Step S4, deep cooling and heat preservation, deep cooling and heat preservation of the aluminum-zinc-magnesium-copper alloy after the solid solution treatment;

[0012] Step S5, deep cold rolling, rolling the aluminum-zinc-magnesium-copper alloy after heat preservation;

[0013] Step S6: natural aging.

[0014] Furthermore, in step S1, the raw materials of aluminum-zinc-magnesium-copper alloy are put into a heating crucible according to the mass ratio and melted into liquid state, and the heating temperature is 765-780°C.

[0015] Furthermore, in step S2, the hot extrusion temperature is 440-450°C.

[0016] Further, step S3 includes the following steps:

[0017] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for heating and heat preservation;

[0018] Step S32, secondary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate in a furnace to further heat it and keep it warm;

[0019] Step S33, solution cooling, taking out the aluminum-zinc-magnesium-copper alloy sheet after the insulation is completed and cooling it.

[0020] Furthermore, in step S31, the temperature in the furnace is raised to 455-460°C.

[0021] Furthermore, in step S33, the aluminum-zinc-magnesium-copper alloy plate is rapidly cooled.

[0022] Furthermore, in step S4, the aluminum-zinc-magnesium-copper alloy after the solution treatment is immersed in liquid nitrogen for heat preservation.

[0023] Furthermore, in step S5, the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is rolled for multiple times, and before each rolling, the alloy needs to be immersed in liquid nitrogen for a period of time.

[0024] Furthermore, in step S6, the rolled aluminum-zinc-magnesium-copper alloy is placed at room temperature for a period of time.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] (1) The deep cold rolling method of the aluminum-zinc-magnesium-copper alloy of the present invention combines the spray deposition process and the deep cold rolling technology, and the surface hardness is as high as 210-230HV5, the tensile strength is as high as 700-730MPa, and the elongation is maintained at an excellent level of 10-12%, which meets the strict standards of high-precision and high-performance application fields and shows broad application prospects and market value.

[0027] (2) The deep cold rolling method of the aluminum-zinc-magnesium-copper alloy of the present invention immerses the aluminum-zinc-magnesium-copper alloy in liquid nitrogen for heat preservation before deep cold rolling, which can effectively avoid alloy stress concentration and edge cracks during rolling. The obtained aluminum-zinc-magnesium-copper alloy plate has no cracks at a deformation of 80%.

[0028] (3) In the deep cold rolling method of the aluminum-zinc-magnesium-copper alloy of the present invention, the aluminum-zinc-magnesium-copper alloy is immersed in liquid nitrogen for heat preservation during the deep cold rolling process. The low temperature environment has a strong inhibitory effect on the dynamic recovery process inside the alloy, which significantly increases the dislocation density and promotes the formation of substructures such as subgrains, thereby achieving a significant grain refinement. After that, multiple deep cold rolling processes are performed to make the grains as small as nanometer scale, thereby avoiding grain coarsening and surface oxidation of the alloy during thermal deformation, thereby improving the mechanical properties of the alloy.

[0029] (4) The deep cold rolling method of the aluminum-zinc-magnesium-copper alloy of the present invention adopts natural aging and does not require artificial aging process, which simplifies the operation process, reduces energy consumption and equipment investment, and greatly saves labor and energy costs.

[0030] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the following content, and some advantages can be obvious from the description or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the text and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0032] Figure 1 This is a flow chart of a deep cold rolling method for an aluminum-zinc-magnesium-copper alloy in Example 1 of the present invention;

[0033] Figure 2 This is a macroscopic morphology of a plate in a deep cold rolling method of an aluminum-zinc-magnesium-copper alloy in Example 1 of the present invention;

[0034] Figure 3 This is a metallographic diagram of a plate of a deep cold rolling method of an aluminum-zinc-magnesium-copper alloy in Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used to illustrate the principles of the present invention together with the embodiments of the present invention.

[0036] Example 1

[0037] The present embodiment discloses an aluminum-zinc-magnesium-copper alloy, the chemical composition of which, by mass percentage, includes: Zn: 8.8-9.2%, Cu: 2.6-3.0%, Mg: 1.8-2.3%, Zr: 0.1-0.20%, Ti: 0.05-0.10%, Si: ≤0.10%, Fe: ≤0.15%, Mn: ≤0.11%, and the balance is Al.

[0038] This embodiment discloses a deep cold rolling method for the aluminum-zinc-magnesium-copper alloy. Figure 1 , the specific steps include:

[0039] Step S1, preparing a deposition blank; adopting a spray deposition process to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy, placing the raw materials of the aluminum-zinc-magnesium-copper alloy into a heating crucible according to a mass ratio to melt into a liquid, the heating temperature is 765-780° C., the spray nitrogen pressure is 1.1-1.2 MPa, the deposition distance is 680-700 mm, the bottom plate rotation speed is 30-40 r / min, and the return rotation speed is 2-4 mm / min, thereby obtaining a deposition blank of an aluminum-zinc-magnesium-copper alloy.

[0040] It should be noted that the spray deposition process is a process in which metal or non-metal materials are melted into a liquid state, and a solid-liquid two-phase particle jet is formed in an inert atmosphere with the help of high-pressure inert gas or mechanical centrifugal atomization. The jet is then sprayed onto a cooler substrate at a high speed to form an atomized deposition blank through impact, bonding, and solidification, thereby preparing components with specific shapes and properties.

[0041] Step S2, preparing an alloy material plate; using a hot extruder 880UST to hot extrude the deposited billet obtained in step S1 to increase the density of the deposited billet to more than 98%, the process parameters are: hot extrusion temperature of 440-450°C, extrusion rate of 0.3-0.5 mm / s, extrusion ratio of 16-20, thereby forming an aluminum-zinc-magnesium-copper alloy plate with good density.

[0042] Step S3, solution treatment: The aluminum-zinc-magnesium-copper alloy sheet formed by hot extrusion is subjected to a two-stage solution treatment to effectively dissolve more coarse second phase particles into the matrix, thereby improving the plastic deformation ability of the material.

[0043] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for solid solution treatment and heating to 455-460°C, keeping the temperature for 2-2.5 hours, and the heating rate is 1-10°C / min.

[0044] Step S32, secondary solid solution, heating to 480-485°C, keeping warm for 2-2.5h, heating rate of 1-10°C / min.

[0045] Step S33, solution cooling; after the insulation is completed, the alloy material plate is taken out from the heat treatment furnace and quickly cooled by water cooling, so as to inhibit the re-precipitation of the second phase, so that the alloy composition remains stable, so as to achieve the purpose of improving the corrosion resistance of the alloy material and enhancing the mechanical properties.

[0046] Step S4, deep cooling and heat preservation: immersing the aluminum-zinc-magnesium-copper alloy after the solid solution treatment in liquid nitrogen for heat preservation, the liquid nitrogen temperature is -196°C, and the heat preservation time is 1 to 2 hours, so as to ensure that the material has good plastic deformation ability in the subsequent rolling process.

[0047] Step S5, deep cold rolling; the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is immediately taken out of the liquid nitrogen and subjected to multiple rolling passes, wherein the reduction rate of a single rolling pass is 6-10%, and the total deformation is 75-85%. Before each rolling pass, the alloy needs to be immersed in liquid nitrogen for 30-40 minutes to prevent cracks from forming in the material during the rolling process.

[0048] Step S6, natural aging; placing the rolled aluminum-zinc-magnesium-copper alloy at room temperature to allow its structure and properties to change over time, making the alloy structure more stable, thereby improving the hardness and strength of the material and obtaining a high-strength and tough alloy plate, and the natural aging time is greater than or equal to 7 days.

[0049] It should be noted that the improvement in the performance of aluminum alloy materials by natural aging is permanent and will not decrease over time. Since it does not require expensive equipment and a large amount of energy consumption, this treatment method can save costs and improve production efficiency.

[0050] See also Figure 2 The aluminum-zinc-magnesium-copper alloy obtained by the deep cold rolling method of the aluminum-zinc-magnesium-copper alloy of this embodiment has uniform deformation structure, and the formed plate has no cracks under 80% large variation; see Figure 3 The aluminum-zinc-magnesium-copper alloy obtained by the deep cold rolling method of the aluminum-zinc-magnesium-copper alloy in this embodiment has uniform microstructure and fine grains.

[0051] Example 2

[0052] This embodiment is another implementation method based on Embodiment 1.

[0053] The specific steps include:

[0054] Step S1, preparing a deposition blank; adopting a spray deposition process to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy, placing the raw materials of the aluminum-zinc-magnesium-copper alloy into a heating crucible according to a mass ratio to melt into a liquid, the heating temperature is 765°C, the spray nitrogen pressure is 1.1MPa, the deposition distance is 685mm, the bottom plate speed is 30r / min, and the return speed is 3mm / min, so as to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy.

[0055] Step S2, preparing an alloy material plate; using a hot extruder 880UST to hot extrude the deposited billet obtained in step S1 to improve the density of the deposited billet, the process parameters are: hot extrusion temperature of 440°C, extrusion rate of 0.35mm / s, extrusion ratio of 16, thereby forming an aluminum-zinc-magnesium-copper alloy plate with good density.

[0056] Step S3, solution treatment: The aluminum-zinc-magnesium-copper alloy sheet formed by hot extrusion is subjected to a two-stage solution treatment to effectively dissolve more coarse second phase particles into the matrix, thereby improving the plastic deformation ability of the material.

[0057] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for solid solution treatment, heating to 455°C and keeping it for 2.5 hours, with a heating rate of 5°C / min.

[0058] Step S32, secondary solid solution, heating to 480°C and keeping for 2.5h, with a heating rate of 5°C / min.

[0059] Step S33, solution cooling; after the insulation is completed, the alloy material plate is taken out from the heat treatment furnace and quickly cooled by water cooling, so as to inhibit the re-precipitation of the second phase, so that the alloy composition remains stable, so as to achieve the purpose of improving the corrosion resistance of the alloy material and enhancing the mechanical properties.

[0060] Step S4, deep cooling and heat preservation; immersing the aluminum-zinc-magnesium-copper alloy after the solid solution treatment in liquid nitrogen for heat preservation, the liquid nitrogen temperature is -196°C, and the heat preservation time is 1.5h, so as to ensure that the material has good plastic deformation ability in the subsequent rolling process.

[0061] Step S5, deep cold rolling; the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is immediately taken out of the liquid nitrogen and subjected to multiple rolling passes, wherein the reduction rate of a single rolling pass is 6%, the total deformation is 78%, and the alloy needs to be immersed in liquid nitrogen for 30 minutes before each rolling pass to prevent cracks in the material during the rolling process.

[0062] Step S6, natural aging; placing the rolled aluminum-zinc-magnesium-copper alloy at room temperature to allow its structure and properties to change over time, making the alloy structure more stable, thereby improving the hardness and strength of the material and obtaining a high-strength and tough alloy plate. The natural aging time is 7 days.

[0063] Example 3

[0064] This embodiment is another implementation method based on Embodiment 1.

[0065] The specific steps include:

[0066] Step S1, preparing a deposition blank; adopting a spray deposition process to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy, placing the raw materials of the aluminum-zinc-magnesium-copper alloy into a heating crucible according to a mass ratio to melt into a liquid, the heating temperature is 775°C, the spray nitrogen pressure is 1.2MPa, the deposition distance is 690mm, the bottom plate speed is 40r / min, and the return speed is 3mm / min, so as to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy.

[0067] Step S2, preparing an alloy material plate; using a hot extruder 880UST to hot extrude the deposited billet obtained in step S1 to increase the density of the deposited billet to more than 98%, and the process parameters are: hot extrusion temperature of 450°C, extrusion rate of 0.5mm / s, extrusion ratio of 18, thereby forming an aluminum-zinc-magnesium-copper alloy plate with good density.

[0068] Step S3, solution treatment: The aluminum-zinc-magnesium-copper alloy sheet formed by hot extrusion is subjected to a two-stage solution treatment to effectively dissolve more coarse second phase particles into the matrix, thereby improving the plastic deformation ability of the material.

[0069] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for solid solution treatment, heating to 460°C and keeping it for 2 hours, with a heating rate of 8°C / min.

[0070] Step S32, secondary solid solution, heating to 485°C and keeping for 2h, with a heating rate of 8°C / min.

[0071] Step S33, solution cooling; after the insulation is completed, the alloy material plate is taken out from the heat treatment furnace and quickly cooled by water cooling, so as to inhibit the re-precipitation of the second phase, so that the alloy composition remains stable, so as to achieve the purpose of improving the corrosion resistance of the alloy material and enhancing the mechanical properties.

[0072] Step S4, deep cooling and heat preservation; immersing the aluminum-zinc-magnesium-copper alloy after the solid solution treatment in liquid nitrogen for heat preservation, the liquid nitrogen temperature is -196°C, and the heat preservation time is 1.2h, so as to ensure that the material has good plastic deformation ability in the subsequent rolling process.

[0073] Step S5, deep cold rolling; the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is immediately taken out of the liquid nitrogen and subjected to multiple rolling passes, wherein the reduction rate of a single rolling pass is 10%, the total deformation is 85%, and the alloy needs to be immersed in liquid nitrogen for 40 minutes before each rolling pass to prevent cracks in the material during the rolling process.

[0074] Step S6, natural aging; placing the rolled aluminum-zinc-magnesium-copper alloy at room temperature to allow its structure and properties to change over time, making the alloy structure more stable, thereby improving the hardness and strength of the material and obtaining a high-strength and tough alloy plate. The natural aging time is 7 days.

[0075] Example 4

[0076] This embodiment is another implementation method based on Embodiment 1.

[0077] The present embodiment discloses an aluminum-zinc-magnesium-copper alloy, the chemical composition of which, by mass percentage, includes: Zn: 8.9%, Cu: 2.8%, Mg: 1.9%, Zr: 0.15%, Ti: 0.07%, Si: ≤0.10%, Fe: ≤0.15%, Mn: ≤0.11%, and the balance is Al.

[0078] This embodiment discloses a deep cold rolling method of the aluminum-zinc-magnesium-copper alloy, and the specific steps include:

[0079] Step S1, preparing a deposition blank; adopting a spray deposition process to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy, placing the raw materials of the aluminum-zinc-magnesium-copper alloy into a heating crucible according to a mass ratio to melt into a liquid, the heating temperature is 770°C, the spray nitrogen pressure is 1.1MPa, the deposition distance is 690mm, the bottom plate speed is 35r / min, and the return speed is 3mm / min, so as to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy.

[0080] Step S2, preparing an alloy material plate; using a hot extruder 880UST to hot extrude the deposited billet obtained in step S1 so that the density of the deposited billet reaches more than 98%, and the process parameters are: hot extrusion temperature of 446°C, extrusion rate of 0.4mm / s, and extrusion ratio of 19, thereby forming an aluminum-zinc-magnesium-copper alloy plate with good density.

[0081] Step S3, solution treatment: The aluminum-zinc-magnesium-copper alloy sheet formed by hot extrusion is subjected to a two-stage solution treatment to effectively dissolve more coarse second phase particles into the matrix, thereby improving the plastic deformation ability of the material.

[0082] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for solid solution treatment, heating the temperature to 458°C, keeping the temperature for 2.3 hours, and the heating rate is 5°C / min.

[0083] Step S32, secondary solid solution, heating to 480°C and keeping for 2.3h, heating rate is 5°C / min.

[0084] Step S33, solution cooling; after the insulation is completed, the alloy material plate is taken out from the heat treatment furnace and quickly cooled by water cooling, so as to inhibit the re-precipitation of the second phase, so that the alloy composition remains stable, so as to achieve the purpose of improving the corrosion resistance of the alloy material and enhancing the mechanical properties.

[0085] Step S4, deep cooling and heat preservation; immersing the aluminum-zinc-magnesium-copper alloy after the solid solution treatment in liquid nitrogen for heat preservation, the liquid nitrogen temperature is -196°C, and the heat preservation time is 1.4h, so as to ensure that the material has good plastic deformation ability in the subsequent rolling process.

[0086] Step S5, deep cold rolling; the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is immediately taken out of the liquid nitrogen and subjected to multiple rolling passes, wherein the reduction rate of a single rolling pass is 9%, the total deformation is 78%, and the alloy needs to be immersed in liquid nitrogen for 35 minutes before each rolling pass to prevent cracks in the material during the rolling process.

[0087] Step S6, natural aging; placing the rolled aluminum-zinc-magnesium-copper alloy at room temperature to allow its structure and properties to change over time, making the alloy structure more stable, thereby improving the hardness and strength of the material and obtaining a high-strength and tough alloy plate. The natural aging time is 7 days.

[0088] Example 5

[0089] This embodiment is another implementation method based on Embodiment 1.

[0090] The present embodiment discloses an aluminum-zinc-magnesium-copper alloy, the chemical composition of which, by mass percentage, includes: Zn: 9.1%, Cu: 2.9%, Mg: 2.1%, Zr: 0.16%, Ti: 0.06%, Si: ≤0.10%, Fe: ≤0.15%, Mn: ≤0.11%, and the balance is Al.

[0091] This embodiment discloses a deep cold rolling method of the aluminum-zinc-magnesium-copper alloy, and the specific steps include:

[0092] Step S1, preparing a deposition blank; adopting a spray deposition process to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy, placing the raw materials of the aluminum-zinc-magnesium-copper alloy into a heating crucible according to a mass ratio to melt into a liquid, the heating temperature is 775°C, the spray nitrogen pressure is 1.1MPa, the deposition distance is 685mm, the bottom plate speed is 38r / min, and the return speed is 3mm / min, so as to obtain a deposition blank of an aluminum-zinc-magnesium-copper alloy.

[0093] Step S2, preparing an alloy material plate; using a hot extruder 880UST to hot extrude the deposited billet obtained in step S1 so that the density of the deposited billet reaches more than 98%, and the process parameters are: hot extrusion temperature of 440°C, extrusion rate of 0.3mm / s, and extrusion ratio of 18, thereby forming an aluminum-zinc-magnesium-copper alloy plate with good density.

[0094] Step S3, solution treatment: The aluminum-zinc-magnesium-copper alloy sheet formed by hot extrusion is subjected to a two-stage solution treatment to effectively dissolve more coarse second phase particles into the matrix, thereby improving the plastic deformation ability of the material.

[0095] Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for solid solution treatment, heating to 455°C and keeping it for 2.5 hours, with a heating rate of 5°C / min.

[0096] Step S32, secondary solid solution, heating to 480°C and keeping for 2.5h, with a heating rate of 5°C / min.

[0097] Step S33, solution cooling; after the insulation is completed, the alloy material plate is taken out from the heat treatment furnace and quickly cooled by water cooling, so as to inhibit the re-precipitation of the second phase, so that the alloy composition remains stable, so as to achieve the purpose of improving the corrosion resistance of the alloy material and enhancing the mechanical properties.

[0098] Step S4, deep cooling and heat preservation; immersing the aluminum-zinc-magnesium-copper alloy after the solid solution treatment in liquid nitrogen for heat preservation, the liquid nitrogen temperature is -196°C, and the heat preservation time is 1.2h, so as to ensure that the material has good plastic deformation ability in the subsequent rolling process.

[0099] Step S5, deep cold rolling; the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is immediately taken out of the liquid nitrogen and subjected to multiple rolling passes, wherein the reduction rate of a single rolling pass is 8%, the total deformation is 82%, and the alloy needs to be immersed in liquid nitrogen for 35 minutes before each rolling pass to prevent cracks in the material during the rolling process.

[0100] Step S6, natural aging; placing the rolled aluminum-zinc-magnesium-copper alloy at room temperature to allow its structure and properties to change over time, making the alloy structure more stable, thereby improving the hardness and strength of the material and obtaining a high-strength and tough alloy plate. The natural aging time is 7 days.

[0101] Table 1 Mechanical test performance data of samples in Examples 2 to 5

[0102] state Tensile strength / MPa Elongation / % <![CDATA[Hardness / HV5]]> Example 2 713 12 218 Example 3 722 10 226 Example 4 708 11 213 Example 5 717 11 225

[0103] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An aluminum-zinc-magnesium-copper alloy, characterized in that: The chemical composition, by mass percentage, includes: Zn: 8.8-9.2%, Cu: 2.6-3.0%, Mg: 1.8-2.3%, Zr: 0.10-0.20%, Ti: 0.05-0.10%, Si: ≤0.10%, Fe: ≤0.15%, Mn: ≤0.11%, and the balance is Al.

2. According to the aluminum-zinc-magnesium-copper alloy of claim 1, a deep cold rolling method of the aluminum-zinc-magnesium-copper alloy is provided, characterized in that: The following steps are involved: Step S1, preparing a deposition blank, using a spray deposition process to prepare the deposition blank; Step S2, preparing an alloy material plate, and hot extruding the deposited blank using a hot extruder; Step S3, solution treatment, performing solution treatment on the alloy material plate; Step S4, deep cooling and heat preservation, deep cooling and heat preservation of the aluminum-zinc-magnesium-copper alloy after the solid solution treatment; Step S5, deep cold rolling, rolling the aluminum-zinc-magnesium-copper alloy after heat preservation; Step S6: natural aging.

3. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 2, characterized in that: In the step S1, raw materials of aluminum-zinc-magnesium-copper alloy are put into a heating crucible according to a mass ratio and melted into liquid state, and the heating temperature is 765-780°C.

4. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 3, characterized in that: The hot extrusion temperature in step S2 is 440-450°C.

5. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 4, characterized in that: The step S3 comprises the following steps: Step S31, primary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate formed by hot extrusion into a heat treatment furnace for heating and heat preservation; Step S32, secondary solid solution, placing the aluminum-zinc-magnesium-copper alloy plate in a furnace to further heat it and keep it warm; Step S33, solution cooling, taking out the aluminum-zinc-magnesium-copper alloy sheet after the insulation is completed and cooling it.

6. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 5, characterized in that: In step S31, the temperature in the furnace is raised to 455-460°C.

7. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 6, characterized in that: In the step S33, the aluminum-zinc-magnesium-copper alloy plate is rapidly cooled.

8. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 7, characterized in that: In step S4, the aluminum-zinc-magnesium-copper alloy after the solution treatment is immersed in liquid nitrogen for heat preservation.

9. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 8, characterized in that: In step S5, the aluminum-zinc-magnesium-copper alloy cooled by liquid nitrogen is rolled for multiple times, and before each rolling, the alloy needs to be immersed in liquid nitrogen for a period of time.

10. The deep cold rolling method of aluminum-zinc-magnesium-copper alloy according to claim 9, characterized in that: In the step S6, the rolled aluminum-zinc-magnesium-copper alloy is placed at room temperature for a period of time.

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