Method for preparing aluminum alloy plate and aluminum alloy plate obtained thereby

Abstract

Provided is a method for preparing an aluminium alloy sheet and an aluminium alloy sheet obtained by the method. The preparation method includes: mixing components of an aluminium alloy sheet according to a ratio, melting and refining same, and then casting to form a cast ingot; homogenizing the cast ingot; performing hot rough rolling on the cast ingot after the homogenization treatment to obtain a hot rough rolled plate, controlling the initial rolling temperature of the hot rough rolling to be in the range of 520-530°C, and controlling the passes of the hot rough rolling to be in the range of 13 to 19 passes; performing hot finishing rolling on the hot rough rolled plate to obtain a hot finishing rolled plate; and cooling the hot finishing rolled plate, and sequentially performing primary cold rolling, intermediate annealing, secondary cold rolling and final annealing on the cooled hot finishing rolled sheet. The present disclosure can sufficiently crush and refine large-sized Fe-containing second phases in an aluminium alloy and prepare an aluminium alloy sheet having excellent mechanical properties and formability.

Description

[0001] This application is based on Chinese Patent Application No. 202311623202.7, filed on November 30, 2023, which claims the benefit of priority to the Chinese Patent Application, which is incorporated by reference in its entirety herein.Technical Field

[0002] The present disclosure relates to the technical field of aluminium alloy manufacturing, and in particular, to a preparation method for an aluminium alloy sheet and an aluminium alloy sheet obtained by the method.Background

[0003] Recovery of automotive components has become a main direction of current automobile aluminium alloy development, and it is particularly important to reduce adverse effects on properties such as formability caused by an increase in Fe element content in recycled aluminum. Aluminium alloys, such as 5182 aluminium alloy, is widely used in parts, such as inner plates and structural members, of passenger car covers due to excellent properties such as strength, formability and corrosion resistance, and developing a high-Fe-content aluminium alloy suitable for recycling, such as 5182 aluminium alloy, is an optimal means for improving product competitiveness.

[0004] Automobile parts are generally composed of materials such as an aluminium alloy, iron and plastic, the content of impurity element Fe inevitably exceeds a limit during recycling of an aluminium alloy material, the Fe-containing primary second phase produced in the melt casting process is coarse in size and is rolled by using a conventional hot rolling process, and after the Fe-containing second phase is crushed, the particle size is still significantly larger, which seriously affects the formability and other properties of the plate and limits the recycling of aluminium alloy sheets such as 5182 aluminium alloy.

[0005] A lot of work has been done in the prior art around hot rough rolling. Patent application CN115109906A improves the roping line properties of 6 series aluminium alloy automotive plates by controlling a hot rough rolling process, controlling the Mg 2 Si second phase and texture type. This patent application is applicable to the hot rough rolling of 6 series alloys, and mainly used to control the Mg 2 Si second phase and texture type, and the amount of Mg 2 Si second phase in high-Fe content 5182 aluminium alloy is much less than that in 6 series alloys. This patent application is not applicable to high-Fe content 5182 aluminium alloy, and this patent application needs to maintain a temperature for 1 to 4 hours after homogenization treatment, and thus has low production efficiency.

[0006] The method for preparing an aluminium alloy sheet having a high Fe content in the prior art has the following disadvantages: the Fe-containing second phases are not crushed sufficiently, and the Fe-containing second phases in the obtained alloy have a relatively large size, and therefore have a relatively low elongation, and thus the method cannot meet the requirements of various applications, such as automotive sheet applications. In other words, the existing technology has a poor crushing effect on the Fe-containing second phases in the high-Fe content aluminium alloy sheet, resulting in low properties of the aluminium alloy sheet. Therefore, there is a need to develop a novel preparation method for an aluminium alloy sheet and an aluminium alloy sheet obtained by the method.Summary

[0007] The main object of the present disclosure is to provide a preparation method for an aluminium alloy sheet having a high Fe content and an aluminium alloy sheet obtained by using the method, so as to solve the technical problem in the prior art that the crushing effect of a Fe-containing second phase in a high-Fe content aluminium alloy sheet is not good.

[0008] In order to achieve the described object, according to one aspect of the present disclosure, provided is a preparation method for an aluminium alloy sheet, wherein based on a total weight of the aluminium alloy sheet, the aluminium alloy sheet including the following components by weight percentage: 0.08wt% to 0.20wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02-0.04wt% of Ti, and the balance of Al and inevitable impurities, and a content of each of the impurities is less than 0.05wt%, and the preparation method including the following steps: step S1: mixing components of the aluminium alloy sheet according to the aforementioned ratio, melting and refining, and then casting to form a cast ingot, a thickness of the cast ingot is in the range of 500mm to 650mm; step S2: performing a homogenization treatment on the cast ingot; step S3: performing a hot rough rolling on the cast ingot after the homogenization treatment to obtain a hot rough rolled plate, where an initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 550°C, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes, and is then subjected to continuous rolling at a pass reduction of 35mm to 50mm and a rolling speed of 2.0m / s to 5.0m / s until the last 2 to 4 passes, a reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 3.0m / s, and a final rolling temperature of the hot rough rolling is controlled at 450°C or less; step S4: performing a hot finishing rolling on the hot rough rolled plate to obtain a hot finishing rolled plate; step S5: cooling the hot finishing rolled plate; and step S6: successively performing a primary cold rolling, an intermediate annealing, a secondary cold rolling and a final annealing on the cooled hot finishing rolled sheet to obtain the aluminium alloy sheet.

[0009] Further, the aluminium alloy sheet including the following components by weight percentage: 0.08wt% to 0.15wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02wt% to 0.04wt% of Ti, and the balance of Al and inevitable impurities, based on the total weight of the aluminium alloy sheet.

[0010] Further, step S3 including: performing the hot rough rolling on the cast ingot after the homogenization treatment to obtain the hot rough rolled plate, where the initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 530°C, a number of the hot rough rolling is controlled in the range of 13 to 19 passes, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes and then subjected to continuous rolling at a pass reduction of 35mm to 50mm and a rolling speed of 2.0m / s to 3.5m / s until the last 2 to 4 passes, the reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 1.5m / s, and the final rolling temperature of the hot rough rolling is controlled at 450°C or less.

[0011] Further, in step S2, the homogenizing treatment on the cast ingot including: heating the cast ingot at a heating rate of 30°C / h to 60°C / h to reach a temperature of 420°C to 480°C, then maintaining the temperature for 4h to 8h, and then heating the cast ingot at a heating rate of 30°C / h to 60°C / h to reach a temperature of 520°C to 550°C, and then maintaining the temperature for 8h to 12h.

[0012] Further, in step S4, the pass of the hot finishing rolling is controlled in the range of 2 to 5 passes, the pass reduction rate is in the range of 20% to 50%, the reduction rate of the next pass is not less than the reduction rate of the previous pass, the reduction rate of the final pass is more than 40%, and a temperature at the outlet of the hot finishing rolling is in the range of 270°C to 300°C.

[0013] Further, in step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, a duration of the intermediate annealing is in the range of 2h to 8h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, and a duration of the final annealing is in the range of 10s to 60s.

[0014] In step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, a duration of the intermediate annealing is in the range of 3h to 8h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, and a duration of the final annealing is in the range of 10s to 60s.

[0015] Further, the hot rough rolled plate obtained in step S3 has a thickness in the range of 20mm to 35mm.

[0016] Further, the hot finishing rolled plate obtained in step S4 has a thickness in the range of 4mm to 8mm.

[0017] Further, after the hot rough rolling in step S3 and the hot finishing rolling in step S4, a total deformation of the hot finishing rolled plate is greater than 98%.

[0018] Further, in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes including: hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 3.0m / s.

[0019] Further, in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3-5 passes including: hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 1.5m / s.

[0020] Further, in the aluminium alloy sheet, a number of AlFeMn phases having an equivalent circular diameter of less than 5µm accounts for above or equal to 95%, and a maximum equivalent circular diameter of AlFeMn phases in the aluminium alloy sheet is less than 10µm.

[0021] According to another aspect of the present disclosure, provided is an aluminium alloy sheet obtained by using the preparation method for an aluminium alloy sheet, where the aluminium alloy sheet has an elongation A 50 above or equal to 27%.

[0022] By applying the technical solution of the present disclosure, by strictly controlling the process parameters such as the initial rolling temperature, the number of hot rough rolling passes, the pass reduction, and the rolling speed during the hot rough rolling process, the large-sized Fe-containing second phases in the aluminium alloy can be fully crushed and refined, and the size of the Fe-containing second phases in the aluminium alloy sheet can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminium alloy and increasing the Fe content in the aluminium alloy sheet, which is beneficial to the recycling of the aluminium alloy. In addition, the core and surface structures of the aluminium alloy sheet are more uniform, an aluminium alloy sheet having excellent mechanical properties and formability can be prepared, the production cycle of hot rough rolling is shortened, the production efficiency is improved, and the production costs of the aluminium alloy sheet are reduced.Detailed Description of the Embodiments

[0023] It should be noted that, in the case of no conflict, the embodiments and the features in the embodiments of the present application can be combined with each other. The present disclosure will be described in detail below with reference to examples. The following examples are merely exemplary, and are not intended to limit the scope of protection of the present disclosure.

[0024] As described in the background of the present disclosure, the poor crushing effect of the Fe-containing second phases in a high-Fe content aluminium alloy sheet in the prior art leads to low properties of the aluminium alloy sheet. In order to solve the described problem in the prior art, a typical embodiment of the present disclosure provides a preparation method for an aluminium alloy sheet, and based on a total weight of the aluminium alloy sheet, the aluminium alloy sheet including the following components by weight percentage: 0.08wt% to 0.20wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02wt% to 0.04wt% of Ti, and the balance of Al and inevitable impurities, and a content of each of the impurities is less than 0.05wt%. The preparation method including the following steps: step S1: mixing components of the aluminium alloy sheet according to the aforementioned ratio, melting and refining, and then casting to form a cast ingot, a thickness of the cast ingot is in the range of 500mm to 650mm, for example, 520mm to 630mm, 540mm to 610mm, 560mm to 590mm or 570mm to 580mm; step S2: performing a homogenization treatment on the cast ingot; step S3: performing a hot rough rolling on the cast ingot after the homogenization treatment to obtain a hot rough rolled plate, where an initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 530°C, for example, 522°C to 528°C, 524°C to 526°C, 532°C to 538°C, 534°C to 536°C, 542°C to 548°C or 544°C to 546°C, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes, and is then subjected to continuous rolling at a pass reduction of 35mm to 60mm, for example, 37mm to 48mm, 39mm to 46mm, 41mm to 44mm or 51mm to 54mm, and a rolling speed of 2.0m / s to 5.0m / s, for example, 2.2m / s to 3.3m / s, 2.4m / s to 3.1m / s, 2.6m / s to 2.9m / s, 2.7m / s to 2.8m / s, 3.7m / s to 3.8m / s or 4.7m / s to 4.8m / s until the last 2 to 4 passes, a reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 3.0m / s, for example, 0.7m / s to 1.3m / s, 0.9m / s to 1.1m / s, 1.7m / s to 2.3m / s, 1.9m / s to 2.1m / s, 2.1m / s to 2.8 or 2.3m / s to 2.6m / s, and a final rolling temperature of the hot rough rolling is controlled at 450°C or less; step S4: performing a hot finishing rolling on the hot rough rolled plate to obtain a hot finishing rolled plate; step S5: cooling the hot finishing rolled plate; and step S6: successively performing a primary cold rolling, an intermediate annealing, a secondary cold rolling and a final annealing on the cooled hot finishing rolled sheet to obtain the aluminium alloy sheet.

[0025] By applying the technical solution of the present disclosure, by strictly controlling the process parameters such as the initial rolling temperature, the number of hot rough rolling passes, the pass reduction, and the rolling speed during the hot rough rolling process, the large-sized Fe-containing second phases in the aluminium alloy can be fully crushed and refined, and the size of the Fe-containing second phases in the aluminium alloy sheet can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminium alloy and increasing the Fe content in the aluminium alloy sheet, which is beneficial to the recycling of the aluminium alloy. In addition, the core and surface structures of the aluminium alloy sheet are more uniform, an aluminium alloy sheet having excellent mechanical properties and formability can be prepared, the production cycle of hot rough rolling is shortened, the production efficiency is improved, and the production costs of the aluminium alloy sheet are reduced.

[0026] The preparation method for an aluminium alloy sheet of the present disclosure mainly includes the steps of casting, homogenizing, hot rough rolling and hot finishing rolling. By controlling the hot rough rolling process, by means of preforming the high-temperature initial rolling, reducing the number of hot rough rolling passes, increasing the reduction of hot rough rolling passes and high-speed rolling in the hot rough rolling process, the large-sized Fe-containing second phases in the aluminium alloy having a high Fe content can be sufficiently crushed and refined, thereby reducing the adverse effect of Fe element on the aluminium alloy; while the production efficiency is improved, the core and the surface structures of the aluminium alloy sheet are more uniform, and an aluminium alloy sheet having a high Fe content and having excellent properties, especially improved formability, can be prepared. For example, a high-Fe content 5182 aluminium alloy sheet which is comparable in properties to a low-Fe content 5182 aluminium alloy sheet can be obtained.

[0027] In some embodiments of the present disclosure, based on the total weight of the aluminium alloy sheet, the aluminium alloy sheet includes the following components by weight percentage: 0.08wt% to 0.15wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02wt% to 0.04wt% of Ti, and the balance of Al and inevitable impurities.

[0028] In some embodiments of the present disclosure, step S3 comprises: performing the hot rough rolling on the cast ingot after the homogenization treatment to obtain the hot rough rolled plate, where an initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 530°C, a number of hot rough rolling passes is controlled in the range of 13 to 19 passes, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes and then subjected to continuous rolling at a pass reduction of 35mm to 50mm and a rolling speed of 2.0m / s to 3.5m / s until the last 2 to 4 passes, the reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 1.5m / s, and the final rolling temperature of the hot rough rolling is controlled at 450°C or less.

[0029] By strictly controlling the process parameters such as the initial rolling temperature, the number of hot rough rolling passes, the pass reduction, and the rolling speed during the hot rough rolling process, the large-sized Fe-containing second phases in the aluminium alloy can be fully crushed and refined, and the size of the Fe-containing second phases in the aluminium alloy sheet can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminium alloy and increasing the Fe content in the aluminium alloy sheet, which is beneficial to the recycling of the aluminium alloy. In addition, the core and surface structures of the aluminium alloy sheet are more uniform, an aluminium alloy sheet having excellent mechanical properties and formability can be prepared, the production cycle of hot rough rolling is shortened, the production efficiency is improved, and the production costs of the aluminium alloy sheet are reduced.

[0030] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S1, a conventional casting device in the art may be used for casting, and preferably, a semi-continuous casting device may be used for casting to form a cast ingot. In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S3, the cast ingot after the homogenization treatment is directly taken out of a furnace and subjected to hot rough rolling to obtain a hot rough rolled plate. In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S4, the hot rough rolled plate may be subjected to continuous hot finishing rolling to obtain a hot finishing rolled plate.

[0031] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S2, homogenizing the cast ingot includes: heating the cast ingot to a temperature of 420°C to 480°C, for example, 430°C to 470°C, 440°C to 460°C or 445°C to 450°C, at a heating rate of 30°C / h to 60°C / h, for example, 35°C / h to 55°C / h, 40°C / h to 50°C / h or 38°C / h to 45°C / h, maintaining the temperature for 4h to 8h, for example, 5h to 7h, then heating to 520°C to 550°C, for example, 525°C to 545°C, 530°C to 540°C or 535°C to 547°C at a heating rate of 30°C / h to 60°C / h, for example, 35°C / h to 55°C / h, 40°C / h to 50°C / h or 38°C / h to 45°C / h, maintaining the temperature for 8h to 12h, for example, 9h to 11 h or 8h to 10 h. By performing the homogenization treatment on the cast ingot, the microstructure of the aluminium alloy can be significantly improved, the cast stress is eliminated, the segregation of the cast ingot is reduced, and the quality of the cast ingot is significantly improved.

[0032] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S4, the number of hot finishing rolling is controlled in the range of 2 to 5 passes, for example, 3 to 4 passes, the pass reduction rate is in the range of 20% to 50%, for example, 25% to 45%, 30% to 40% or 28% to 35%, the reduction rate of the next pass is not less than the reduction rate of the previous pass, the last pass reduction rate is more than 40%, and a temperature at the outlet of the hot finishing rolling is in the range of 270°C to 300°C, for example, 280°C to 290°C or 275°C to 285°C. By controlling the process parameters in the hot finishing rolling process, not only AlFeMn phase size and surface quality satisfying the final requirements can be obtained, but also the strength and hardness of the aluminium alloy can be improved.

[0033] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, for example, 320°C to 380°C, 340°C to 360°C or 330°C to 350°C, a duration of the intermediate annealing is in the range of 2h to 8h, for example, 2h to 7h or 5h to 6h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, for example, 490°C to 530°C, 500°C to 520°C or 510°C to 535°C, and a duration of the final annealing is in the range of 10s to 60s, for example, 20s to 50s, 30s to 40s or 15s to 55s. By controlling the temperature and duration of the intermediate annealing, the pass reduction rate of the secondary cold rolling, and the temperature and duration of the final annealing in the described ranges, the mechanical properties and processability of the aluminium alloy sheet can be improved.

[0034] In some embodiments of the present disclosure, in step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, a duration of the intermediate annealing is in the range of 3h to 8h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, and a duration of the final annealing is in the range of 10s to 60s. By controlling the temperature and duration of the intermediate annealing, the pass reduction rate of the secondary cold rolling, and the temperature and duration of the final annealing within the described ranges, the mechanical properties and the processability of the aluminium alloy sheet can be further improved.

[0035] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, after final annealing, cooling may be performed, for example, water cooling may be performed.

[0036] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in order to prepare an aluminium alloy sheet which meets specific application requirements and has a relatively high strength, the hot rough rolled plate obtained in step S3 has a thickness in the range of 20mm to 35mm. Specifically, the thickness of the hot rough rolled plate obtained in step S3 may be in the range of: 20mm to 35mm, 21mm to 34mm, 22mm to 33mm, 23mm to 32mm, 24mm to 31mm, 25mm to 30mm, 26mm to 29mm or 27mm to 28mm.

[0037] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, in order to prepare an aluminium alloy sheet which meets specific application requirements and has a relatively high strength, a thickness of the hot finishing rolled plate obtained in step S4 is in the range of 4mm to 8mm. Specifically, the thickness of the hot finishing rolled plate obtained in step S4 can be in the range of 4mm to 8mm, 4.5mm to 7.5mm, 5mm to 7mm, 5.5mm to 6.5mm or 4mm to 5mm.

[0038] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, after the hot rough rolling in step S3 and the hot finishing rolling in step S4, a total deformation of the hot finishing rolled plate is greater than 98%. By controlling the total deformation of the hot finishing rolled plate after hot rough rolling and hot finishing rolling within the described range, an aluminium alloy sheet having excellent mechanical properties and formability can be obtained.

[0039] In some embodiments of the present disclosure, in the described preparation method for an aluminium alloy sheet, in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes comprises hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 3.0m / s. By controlling the rolling speed within the described range, it can be ensured that the cast ingot, after the homogenization treatment, is successfully processed by a hot roughing mill.

[0040] In some embodiments of the present disclosure, in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes comprises hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 1.5m / s.

[0041] In some embodiments of the present disclosure, in the preparation method for an aluminium alloy sheet, a number of AlFeMn phases having an equivalent circular diameter of less than 5µm in the aluminium alloy sheet accounts for above or equal to 95%, and a maximum equivalent circular diameter of AlFeMn phases in the aluminium alloy sheet is less than 10µm.By controlling the ratio of the number of the AlFeMn phases having an equivalent circular diameter of less than 5µm in the aluminium alloy sheet and the maximum equivalent circular diameter of the AlFeMn phases in the aluminium alloy sheet within the described ranges, it can be ensured that the Fe-containing second phases in the aluminium alloy are sufficiently crushed and refined, and an aluminium alloy sheet having excellent mechanical properties and formability can be obtained.

[0042] Another typical embodiment of the present disclosure provides an aluminium alloy sheet obtained by using the preparation method for an aluminium alloy sheet, wherein the aluminium alloy sheet has an elongation A 50 above or equal to 27%.Controlling the elongation of the aluminium alloy sheet within the described range can ensure excellent formability of the aluminium alloy.

[0043] In the preparation process of the high-Fe content aluminium alloy sheet of the present disclosure, by means of process adjustments, such as increasing the initial rolling temperature of hot rough rolling, reducing the number of hot rough rolling passes, increasing the reduction of hot rough rolling passes and increasing the rolling speed, sufficient crushing of the Fe-containing second phases in the hot-rolled plate blank is achieved, and a high-Fe content aluminium alloy sheet, such as 5182 aluminium alloy sheet, for example, used in automobile interior plates and structural members can be prepared. Of course, the use of the aluminium alloy sheet prepared by the method of the present disclosure is not limited thereto, and the aluminium alloy sheet may also be applied to other uses.

[0044] Compared with the prior art, the significant advantages of the preparation method for an aluminium alloy sheet in the present disclosure mainly lie in the following aspects.

[0045] By means of the present disclosure, the adverse effect of harmful element Fe on an aluminium alloy, such as 5182 aluminium alloy, is reduced, thereby improving the Fe content in the aluminium alloy, and facilitating the recycling of the aluminium alloy.

[0046] The present disclosure strictly limits the initial rolling temperature of hot rough rolling, and by increasing the initial rolling temperature of hot rough rolling, the Fe-containing second phases in the aluminium alloy can be crushed more sufficiently. In the present disclosure, high-temperature rolling is used to achieve the crushing of the Fe-containing second phases, and additional cooling may not be used.

[0047] According to the present disclosure, the reduction of the hot rough rolling passes is increased, the rolling deformation penetrates deeply into the core part of the cast ingot, so that the Fe-containing second phases (AlFeMn phase) in the cast ingot are all crushed, achieving the effect of uniform crushing of the Fe-containing second phases in the surface layer and in the core of the cast ingot. Furthermore, the presence of residual large-sized Fe-containing second phases in the core are significantly reduced.

[0048] The process parameters provided by the present disclosure, such as the initial rolling temperature of hot rough rolling, the number of hot rough rolling passes, the reduction of hot rough rolling passes and the rolling speed, enable the Fe-containing second phases in the aluminium alloy with a high Fe content to be fully crushed and refined, satisfying the conditions of industrial production, and requiring no additional device.

[0049] In the present disclosure, by adjusting the initial rolling temperature of hot rough rolling and reducing the number of hot rough rolling passes, the production cycle of the thermal treatment and the hot rough rolling is shortened, thereby improving the production efficiency and reducing the production costs of the aluminium alloy sheet with a high Fe content.

[0050] The AlFeMn phase is crushed and refined to improve the formability, etc. of the final aluminium alloy sheet, and to ensure that Fe element is increased during the recycling process of aluminium alloys, such as 5182 aluminium alloy, while still maintaining excellent application performance.

[0051] In the present disclosure, rolling is performed directly after performing the homogenization treatment. Compared with the prior art, the production efficiency of the present disclosure is higher.

[0052] In the present disclosure, by means of performing the high-temperature initial rolling, reducing the number of hot rough rolling passes, increasing the reduction of hot rough rolling passes and high-speed rolling in the process of the hot rough rolling, the Fe-containing second phases are fully crushed in the process of the hot rough rolling, so that the elongation of the finished sheet is above or equal to 27%. The properties of the finished sheet obtained in the present disclosure are significantly superior to those of the finished sheets in the prior art.

[0053] In the present disclosure, by adjusting the content of Mn element, Mn element and Fe element are combined into an Al 6 FeMn phase which is relatively less harmful, thereby reducing the adverse effect brought by the harmful element Fe. In the present disclosure, Ti element can refine the cast ingot structure, and then refine the distribution of the AlFeMn phase along grain boundaries.

[0054] The present disclosure will be further described in detail with reference to the following examples, which should not be construed as limiting the scope of protection of the present application.Example 1

[0055] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0056] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 525°C, the hot rough rolling was controlled to be 19 passes, after 3 hot rough rolling passes at a rolling speed of 1.5m / s, continuous rolling was performed for 13 passes at a pass reduction of 35mm and a rolling speed of 2.0m / s, the reduction rate of the next pass was not less than that of the previous pass, the reduction rate of each pass was not less than 30%, the rolling speed was controlled at 1.5m / s, the final rolling temperature of hot rough rolling was 435°C, and the thickness of the hot rough rolled plate was 23mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 22%, 33% and 50% respectively, the outlet temperature of hot finishing rolling was 285°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.42mm, the intermediate annealing temperature was 340°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 530°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Example 2

[0057] The composition of an aluminium alloy included, by weight percentage, 0.11wt% of Si, 4.8wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.04wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0058] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 520°C, the hot rough rolling was controlled to be 17 passes, after 3 hot rough rolling passes at a rolling speed of 1.5m / s, continuous rolling was performed for 11 passes at a pass reduction of 40mm and a rolling speed of 2.5m / s, the reduction rate of the next pass was not less than that of the previous pass, the reduction rate of each pass was not less than 30%, the rolling speed was controlled at 1.0m / s, the final rolling temperature of hot rough rolling was 440°C, and the thickness of the hot rough rolled plate was 27mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 26%, 40% and 46% respectively, the outlet temperature of hot finishing rolling was 290°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.5mm, the intermediate annealing temperature was 300°C, the duration for maintaining the temperature was 8h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 520°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Example 3

[0059] The composition of an aluminium alloy included, by weight percentage, 0.11wt% of Si, 4.8wt% of Mg, 0.32wt% of Mn, 0.28wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0060] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 530°C, the hot rough rolling was controlled to be 15 passes, after 3 hot rough rolling passes at a rolling speed of 1.5m / s, continuous rolling was performed for 9 passes at a pass reduction of 45mm and a rolling speed of 3.0m / s, the reduction rate of the next pass was not less than that of the previous pass, the reduction rate of each pass was not less than 30%, the rolling speed was controlled at 1.0m / s, the final rolling temperature of hot rough rolling was 440°C, and the thickness of the hot rough rolled plate was 23mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 22%, 33% and 50% respectively, the outlet temperature of hot finishing rolling was 293°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.54mm, the intermediate annealing temperature was 320°C, the duration for maintaining the temperature was 6h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 500°C, the duration for maintaining the temperature was 45s, and water cooling was used to finally obtain a finished sheet.Example 4

[0061] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 5.0wt% of Mg, 0.34wt% of Mn, 0.30wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.04wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0062] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 526°C, the hot rough rolling was controlled to be 13 passes, after 3 hot rough rolling passes at a rolling speed of 1.5m / s, continuous rolling was performed for 7 passes at a pass reduction of 50mm and a rolling speed of 3.5m / s, the reduction rate of the next pass was not less than that of the previous pass, the reduction rate of each pass was not less than 30%, the rolling speed was controlled at 1.0m / s, the final rolling temperature of hot rough rolling was 449°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 28%, 33% and 50% respectively, the outlet temperature of hot finishing rolling was 293°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.62mm, the intermediate annealing temperature was 380°C, the duration for maintaining the temperature was 3.5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 520°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Example 5

[0063] The composition of an aluminium alloy included, by weight percentage, 0.15wt% of Si, 5.0wt% of Mg, 0.34wt% of Mn, 0.3wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.04wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0064] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 525°C, the hot rough rolling was controlled to be 19 passes, after 3 hot rough rolling passes at a rolling speed of 1.5m / s, continuous rolling was performed for 13 passes at a pass reduction of 35mm and a rolling speed of 2.0m / s, the reduction rate of the next pass was not less than that of the previous pass, the reduction rate of each pass was not less than 30%, the rolling speed was controlled at 1.5m / s, the final rolling temperature of hot rough rolling was 435°C, and the thickness of the hot rough rolled plate was 23mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 22%, 33% and 50% respectively, the outlet temperature of hot finishing rolling was 285°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.55mm, the intermediate annealing temperature was 400°C, the duration for maintaining the temperature was 3h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 490°C, the duration for maintaining the temperature was 20s, and water cooling was used to finally obtain a finished sheet.Comparative Example 1

[0065] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0066] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 525°C, the hot rough rolling was controlled to be 23 passes, the maximum pass reduction was 28mm, the maximum rolling speed was 2.0m / s, the final rolling temperature of the hot rough rolling was 448°C, and the thickness of the hot rough rolled plate was 32mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 33% and 50% respectively, the outlet temperature of hot finishing rolling was 300°C, the thickness of the hot finishing rolled plate was 8mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.8mm, the intermediate annealing temperature was 350°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 530°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Comparative Example 2

[0067] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0068] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the cast ingot was cooled to 490°C and then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 490°C, the hot rough rolling was controlled to be 19 passes, the maximum pass reduction was 25mm, the maximum rolling speed was 1.0m / s, the final rolling temperature of the hot rough rolling was 435°C, and the thickness of the hot rough rolled plate was 27mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 30%, 37% and 50% respectively, the outlet temperature of hot finishing rolling was 310°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.5mm, the intermediate annealing temperature was 340°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 530°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Comparative Example 3

[0069] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0070] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the cast ingot was cooled to 490°C and then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 485°C, the hot rough rolling was controlled to be 23 passes, the maximum pass reduction was 30mm, the maximum rolling speed was 1.5m / s, the final rolling temperature of the hot rough rolling was 445°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.52mm, the intermediate annealing temperature was 370°C, the duration for maintaining the temperature was 4h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 520°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Comparative Example 4

[0071] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0072] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the cast ingot was cooled to 490°C and then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 490°C, the hot rough rolling was controlled to be 27 passes, the maximum pass reduction was 2mm, the maximum rolling speed was 1.5m / s, the final rolling temperature of the hot rough rolling was 445°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.45mm, the intermediate annealing temperature was 360°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 525°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Comparative Example 5

[0073] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0074] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy cast ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 515°C, the hot rough rolling was controlled to be 25 passes, the maximum pass reduction was 25mm, the maximum rolling speed was 1.0m / s, the final rolling temperature of the hot rough rolling was 445°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6.1mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.55mm, the intermediate annealing temperature was 340°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 525°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Comparative Example 6

[0075] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0076] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the cast ingot was cooled to 490°C and then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 490°C, the hot rough rolling was controlled to be 25 passes, the maximum pass reduction was 25mm, the maximum rolling speed was 3.0m / s, the final rolling temperature of the hot rough rolling was 445°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6.1mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.6mm, the intermediate annealing temperature was 350°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 530°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Comparative Example 7

[0077] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0078] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 540°C for 10h; then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 555°C, the hot rough rolling was controlled to be 25 passes, the maximum pass reduction was 25mm, the maximum rolling speed was 3.0m / s, the final rolling temperature of the hot rough rolling was 485°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.5mm, the intermediate annealing temperature was 340°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 525°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Comparative Example 8

[0079] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.7wt% of Mg, 0.34wt% of Mn, 0.25wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0080] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; the high-Fe content 5182 aluminium alloy ingot after homogenization was directly taken out of a furnace for hot rough rolling, the initial rolling temperature of the hot rough rolling was 515°C, the hot rough rolling was controlled to be 9 passes, the maximum pass reduction was 65mm, the maximum rolling speed was 2.5m / s, the final rolling temperature of the hot rough rolling was 485°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.5mm, the intermediate annealing temperature was 360°C, the duration for maintaining the temperature was 4h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 515°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Comparative Example 9

[0081] The composition of an aluminium alloy included, by weight percentage, 0.12wt% of Si, 4.6wt% of Mg, 0.32wt% of Mn, 0.6wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0082] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 515°C, the hot rough rolling was controlled to be 19 passes, the maximum pass reduction was 35mm, the maximum rolling speed was 2.0m / s, the final rolling temperature of the hot rough rolling was 455°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.6mm, the intermediate annealing temperature was 360°C, the duration for maintaining the temperature was 3h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 525°C, the duration for maintaining the temperature was 30s, and water cooling was used to finally obtain a finished sheet.Comparative Example 10

[0083] The composition of an aluminium alloy included, by weight percentage, 0.08wt% of Si, 4.6wt% of Mg, 0.15wt% of Mn, 0.3wt% of Fe, 0.05wt% of Cu, 0.02wt% of Cr, 0.02wt% of Ti, and the balance of Al and impurities each with a content of less than 0.05wt%.

[0084] The alloy was melted according to the described ratio, and the melt was refined (a filter having a pore size of 50ppi was used for filtering, argon gas was used for degassing online, and the hydrogen content was controlled to be 0.13ml / 100g Al), and then cast into a cast ingot with a thickness of 560mm using a semi-continuous casting device. The end of the cast ingot was cut, and the cast ingot was milled before homogenization, and the homogenization conditions were as follows: the heating rate was controlled at 60°C / h, the temperature was increased to 440°C for 4h, and then the heating rate was controlled at 60°C / h, and the temperature was increased to 530°C for 10h; then hot rough rolling was performed, the initial rolling temperature of the hot rough rolling was 515°C, the hot rough rolling was controlled to be 19 passes, the maximum pass reduction was 35mm, the maximum rolling speed was 2.0m / s, the final rolling temperature of the hot rough rolling was 455°C, and the thickness of the hot rough rolled plate was 25mm; and the number of hot finishing rolling passes was 3, and the pass reduction rates were 25%, 29% and 50% respectively, the outlet temperature of hot finishing rolling was 305°C, the thickness of the hot finishing rolled plate was 6mm, a hot rolled plate was obtained, the primary cold rolling was performed to achieve 1.5mm, the intermediate annealing temperature was 340°C, the duration for maintaining the temperature was 5h, the secondary cold rolling was performed to achieve 1.0mm, the final annealing temperature was 525°C, the duration for maintaining the temperature was 60s, and water cooling was used to finally obtain a finished sheet.Test of properties Statistics of size of Fe-containing second phases:

[0085] For the finished sheets obtained in all the examples and comparative examples, SEM scanning samples were randomly taken, and the sample size was 9mm × 9mm. After the samples were mounted, ground and polished, 20 of 500X photos were randomly taken on the cross section of the plate thickness direction parallel to the rolling direction using a tungsten filament scanning electron microscope. 16 of the photos were selected and the Image-Pro Plus 6.0 statistical software was used to count the area and equivalent circular diameter of Fe-containing second phases, the distribution of the equivalent circular diameter and the maximum equivalent circular diameter of the Fe-containing second phases, and the percentage of the Fe-containing second phases having an equivalent circular diameter less than or equal to 5µm was calculated. The test results were listed in Table 1.Test of mechanical properties of finished sheets:

[0086] The finished sheets obtained in all the examples and comparative examples were tested for elongation (A 50 ), yield strength (R p0.2 ) and tensile strength (R s ), all the test samples were sampled in the vertical rolling direction, and for the sample size, the A50 tensile sample recommended by GB / T228 was used. The test results were listed in Table 1. Table 1: Property test results for examples and comparative examplesExperiment No.Percentage of Fe-containing second phases having an equivalent circular diameter ≤ 5 µm (%)Maximum equivalent circular diameter of Fe-containing second phases (mm)Elongation (%)Yield strength (MPa)Tensile Strength (MPa)Example 198828.0125278Example 298.57.628.1126280Example 398.77.228.4126281Example 4996.828.8128283Example 597.88.427.6123273Comparative Example 188.915.625.4113248Comparative Example 288.517.825.2111248Comparative Example 385.319.224.8109245Comparative Example 483.920.524.3108242Comparative Example 584.519.724.4109244Comparative Example 685.218.624.9108245Comparative Example 7----------Comparative Example 8----------Comparative Example 979.426.419101235Comparative Example 1081.821.923.6105238

[0087] It can be determined from Table 1 that the number percentage (%) of the Fe-containing second phases having an equivalent circular diameter less than or equal to 5µm in the finished sheets of Examples 1 to5 was greater than 95%, the maximum equivalent circular diameter size of the Fe-containing second phases was less than 10µm, and the finished sheets of Examples 1 to 5 had a higher elongation, a higher yield strength and a higher tensile strength. In contrast, the number percentage (%) of the Fe-containing second phases having an equivalent circular diameter less than or equal to 5µm in the finished sheets of Examples 1 to 6 and 9 to 10 was significantly lower and the maximum equivalent circular diameter size of the Fe-containing second phases was significantly larger, and the finished sheets of Comparative Examples 1 to 6 and 9 to 10 had a lower elongation, a lower yield strength and a lower tensile strength. Comparative Examples 1 to 10 did not meet the requirements of the present disclosure, leading to the following results.

[0088] In Comparative Example 1, due to the large number of hot rough rolling passes, the reduction of a single pass was relatively small, the deformation of the cast ingot was relatively small in a single pass rolling, and the Fe-containing second phases were not sufficiently crushed, resulting in a relatively large size of the Fe-containing second phases and a relatively low elongation of the finished sheet.

[0089] In Comparative Example 2, as the initial rolling temperature of the hot rough rolling was relatively low, the Fe-containing second phases were not sufficiently crushed during a rolling process, resulting in a relatively large size of the Fe-containing second phases and unqualified elongation of the finished sheet.

[0090] Comparing Comparative Example 3 and Comparative Example 4 with Comparative Example 2, the number of hot rough rolling passes was increased, the reduction of a single pass was small, the deformation of the cast ingot was small in single pass rolling, and the Fe-containing second phases were even less crushed, resulting in a relatively large size of the Fe-containing second phases and unqualified elongation of the finished sheet.

[0091] In Comparative Example 5, due to the slow rolling speed of the hot rough rolling, the deformation of the cast ingot during the rolling process was mainly in the surface or subsurface layer, and the Fe-containing second phases were not sufficiently crushed, resulting in a larger size and unqualified elongation of the finished sheet.

[0092] In Comparative Example 6, the initial rolling temperature of the hot rough rolling was relatively low. Although the rolling speed was increased, the Fe-containing second phases were still not sufficiently crushed, resulting in a larger size of the Fe-containing second phases and unqualified elongation of the finished sheet.

[0093] In Comparative Example 7, the cast ingot was over-fired due to a too high homogenization temperature.

[0094] In Comparative Example 8, as the reduction of a single pass is too large, the hot rough rolling mill cannot be bitten in, resulting in that the rolling cannot be continued.

[0095] In Comparative Example 9, due to a too high Fe element, the Fe-containing second phases were too coarse, the crushing effect during the hot rough rolling was not good, and the elongation of the finished sheet was not acceptable.

[0096] In Comparative Example 10, as the content of Mn element was low, Fe element cannot be combined with Mn element to form an intermetallic compound which was easily crushed, resulting in a poor crushing effect of Fe element in the rolling process, and further resulting in an unacceptable elongation of the finished sheet.

[0097] It can be determined from the described property test results that by strictly controlling the process parameters such as the initial rolling temperature, the number of hot rough rolling passes, the pass reduction, and the rolling speed during the hot rough rolling process, the large-sized Fe-containing second phases in the aluminium alloy can be fully crushed and refined, and the size of the Fe-containing second phases in the aluminium alloy sheet can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminium alloy and increasing the Fe content in the aluminium alloy sheet, which is beneficial to the recycling of the aluminium alloy. In addition, the core and surface structures of the aluminium alloy sheet are more uniform, an aluminium alloy sheet having excellent mechanical properties and formability can be prepared, the production cycle of hot rough rolling is shortened, the production efficiency is improved, and the production costs of the aluminium alloy sheet are reduced.

[0098] The description above only involves the preferred examples of the present disclosure, and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present disclosure shall fall within the scope of protection of the present disclosure.

Claims

1. A preparation method for an aluminium alloy sheet, wherein based on a total weight of the aluminium alloy sheet, the aluminium alloy sheet comprising the following components by weight percentage: 0.08wt% to 0.20wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02wt% to 0.04wt% of Ti, and the balance of Al and inevitable impurities, and a content of each of the impurities is less than 0.05wt%, and the preparation method comprising the following steps: step S1: mixing components of the aluminium alloy sheet according to the ratio, melting and refining, and then casting to form a cast ingot, a thickness of the cast ingot is in the range of 500mm to 650mm; step S2: performing a homogenization treatment on the cast ingot; step S3: performing a hot rough rolling on the cast ingot after the homogenization treatment to obtain a hot rough rolled plate, wherein an initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 550°C, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes, and is then subjected to continuous rolling at a pass reduction of 35mm to 60mm and a rolling speed of 2.0m / s to 5.0m / s until the last 2 to 4 passes, a reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 3.0m / s, and a final rolling temperature of the hot rough rolling is controlled at 450°C or less; step S4: performing a hot finishing rolling on the hot rough rolled plate to obtain a hot finishing rolled plate; step S5: cooling the hot finishing rolled plate; and step S6: successively performing a primary cold rolling, an intermediate annealing, a secondary cold rolling and a final annealing on the cooled hot finishing rolled sheet to obtain the aluminium alloy sheet.

2. The preparation method for an aluminium alloy sheet according to claim 1, wherein based on the total weight of the aluminium alloy sheet, the aluminium alloy sheet comprising the following components by weight percentage: 0.08wt% to 0.15wt% of Si, 4.0wt% to 5.0wt% of Mg, 0.3wt% to 0.4wt% of Mn, 0.2wt% to 0.4wt% of Fe, less than or equal to 0.15wt% of Cu, less than or equal to 0.10wt% of Cr, less than or equal to 0.25wt% of Zn, 0.02wt% to 0.04wt% of Ti, and the balance of Al and inevitable impurities.

3. The preparation method for the aluminium alloy sheet according to claim 1, wherein step S3 comprising: performing the hot rough rolling on the cast ingot after the homogenization treatment to obtain the hot rough rolled plate, wherein an initial rolling temperature of the hot rough rolling is controlled in the range of 520°C to 530°C, a number of hot rough rolling passes is controlled in the range of 13 to 19 passes, and during the hot rough rolling, the cast ingot after the homogenization treatment is subjected to hot rough rolling for 3 to 5 passes and then subjected to continuous rolling at a pass reduction of 35mm to 50mm and a rolling speed of 2.0m / s to 3.5m / s until the last 2 to 4 passes, the reduction rate of the next pass is not less than that of the previous pass, the reduction rate of each pass is not less than 30%, the rolling speed is controlled in the range of 0.5m / s to 1.5m / s, and the final rolling temperature of the hot rough rolling is controlled at 450°C or less.

4. The preparation method for an aluminium alloy sheet according to claim 1, wherein in step S2, the homogenization treatment on the cast ingot comprising: heating the cast ingot at a heating rate of 30°C / h to 60°C / h to reach a temperature of 420°C to 480°C, then maintaining the temperature for 4h to 8h, and then heating the cast ingot at a heating rate of 30°C / h to 60°C / h to reach a temperature of 520°C to 550°C, and then maintaining the temperature for 8h to 12h.

5. The preparation method for an aluminium alloy sheet according to claim 1, wherein in step S4, the number of the hot finishing rolling is controlled in the range of 2 to 5 passes, the pass reduction rate is in the range of 20% to 50%, the reduction rate of the next pass is not less than the reduction rate of the previous pass, the reduction rate of the final pass is more than 40%, and a temperature at the outlet of the hot finishing rolling is in the range of 270°C to 300°C.

6. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 5, wherein, in step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, a duration of the intermediate annealing is in the range of 2h to 8h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, and a duration of the final annealing is in the range of 10s to 60s.

7. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 5, wherein in step S6, a temperature of the intermediate annealing is controlled in the range of 300°C to 400°C, a duration of the intermediate annealing is in the range of 3h to 8h, a pass reduction rate of the secondary cold rolling is above or equal to 30%, a temperature of the final annealing is in the range of 480°C to 540°C, and a duration of the final annealing is in the range of 10s to 60s.

8. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein the hot rough rolled plate obtained in step S3 has a thickness in the range of 20mm to 35mm.

9. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein the hot finishing rolled plate obtained in step S4 has a thickness in the range of 4mm to 8mm.

10. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein after the hot rough rolling in step S3 and the hot finishing rolling in step S4, a total deformation of the hot finishing rolled plate is greater than 98%.

11. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes comprising: hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 3.0m / s.

12. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein in step S3, hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes comprising hot rough rolling the cast ingot after the homogenization treatment for 3 to 5 passes at a rolling speed of 0.5m / s to 1.5m / s.

13. The preparation method for an aluminium alloy sheet according to any one of claims 1 to 7, wherein in the aluminium alloy sheet, a number of AlFeMn phases having an equivalent circular diameter of less than 5µm accounts for above or equal to 95%, and a maximum equivalent circular diameter of AlFeMn phases in the aluminium alloy sheet is less than 10µm.

14. An aluminium alloy sheet obtained by the preparation method for an aluminium alloy sheet according to any one of claims 1 to 13, wherein an elongation A50 of the aluminium alloy sheet is above or equal to 27%.

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