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

Abstract

The present invention relates to a method for preparing an aluminum alloy plate and an aluminum alloy plate obtained thereby. The preparation method comprises: mixing all components of an aluminum alloy plate in proportion, then melting and refining these components, and then casting the resulting material to form an ingot; homogenizing the ingot; performing hot rough rolling on the homogenized ingot to obtain a hot-rough-rolled plate, wherein the rolling temperature of the hot rough rolling is controlled within a range of 520-530°C, and the number of passes for the hot rough rolling is controlled within a range of 13-19; performing hot finish rolling on the hot-rough-rolled plate to obtain a hot-finish-rolled plate; and cooling the hot-finish-rolled plate and sequentially performing primary cold rolling, intermediate annealing, secondary cold rolling, and final annealing on the cooled hot-finish-rolled plate. According to the present invention, a large-sized Fe-containing second phase in an aluminum alloy can be fully crushed and refined, and an aluminum alloy plate having excellent mechanical properties and formability is prepared.

Description

Method for preparing aluminum alloy plate and aluminum alloy plate obtained by the method

[0001] This application is based on the Chinese application with CN application number 202311623202.7 and application date November 30, 2023, and claims its priority. The disclosed content of the CN application is again introduced as a whole into this application. Technical Field

[0002] The present invention relates to the technical field of aluminum alloy manufacturing, and in particular to a method for preparing an aluminum alloy plate and the aluminum alloy plate obtained by the method. Background Art

[0003] Automotive parts recycling is currently a major development focus for automotive aluminum alloys. Reducing the negative impact of increased Fe content in recycled aluminum on formability and other properties is particularly important. Aluminum alloys such as 5182 are widely used in passenger car fascias, interior panels, and structural components due to their excellent strength, formability, and corrosion resistance. Developing high-Fe aluminum alloys such as 5182 suitable for recycling is an optimal approach to improving product competitiveness.

[0004] Auto parts are generally made of aluminum alloy, iron, plastic and other materials. The recycling process of aluminum alloy materials inevitably leads to excessive content of impurity element Fe. The Fe-containing primary second phase produced during the melting and casting process is coarse in size. When rolled using conventional hot rolling technology, the particle size of the Fe-containing second phase after crushing is still significantly large, which seriously affects the formability and other properties of the plate, and limits the recycling of aluminum alloy plates such as 5182 aluminum alloy.

[0005] A lot of work has been done in the prior art around hot rough rolling. Patent application CN115109906A improves the paint line performance of 6-series aluminum alloy automotive sheets by controlling the hot rough rolling process, controlling the Mg2Si second phase and texture type. This patent application is applicable to hot rough rolling of 6-series alloys and is mainly used to control the Mg2Si second phase and texture type. The amount of Mg2Si second phase in high-Fe content 5182 aluminum alloy is far less than that in 6-series alloys. This patent application is not applicable to high-Fe content 5182 aluminum alloy. Moreover, this patent application requires insulation for 1-4 hours after homogenization treatment, and has low production efficiency.

[0006] Existing methods for producing high-Fe aluminum alloy sheets suffer from the following drawbacks: insufficient crushing of the Fe-containing second phase results in the resulting alloy being large, resulting in low elongation and inability to meet the requirements of various applications, such as automotive sheet applications. This ineffective crushing of the Fe-containing second phase in high-Fe aluminum alloy sheets by existing methods leads to lower performance. Therefore, there is a need for a new method for producing aluminum alloy sheets and the aluminum alloy sheets obtained using this method.

[0007] Summary of the Invention

[0008] The main purpose of the present invention is to provide a method for preparing an aluminum alloy plate with a high Fe content and an aluminum alloy plate obtained by the method, so as to solve the technical problem of poor crushing effect of the Fe-containing second phase in the high Fe content aluminum alloy plate in the prior art.

[0009] To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing an aluminum alloy plate, wherein the aluminum alloy plate comprises the following components in percentage by weight: 0.08 wt%-0.20 wt% Si, 4.0 wt%-5.0 wt% Mg, 0.3 wt%-0.4 wt% Mn, 0.2 wt%-0.4 wt% Fe, ≤0.15 wt% Cu, ≤0.10 wt% Cr, ≤0.25 wt% Zn, 0.02 wt%-0.04 wt% Ti, and the balance Al and unavoidable impurities, wherein the content of each impurity is less than 0.05 wt%. The preparation method comprises the following steps:

[0010] Step S1: mixing the components of the aluminum alloy plate according to a proportion, melting and refining the mixture, and then casting the mixture to form an ingot, wherein the thickness of the ingot is within a range of 500 mm to 650 mm;

[0011] Step S2: homogenizing the ingot;

[0012] Step S3: performing hot rough rolling on the homogenized ingot to obtain a hot rough rolled plate, controlling the start rolling temperature of the hot rough rolling to be within the range of 520-550° C. During the hot rough rolling process, after performing 3-5 hot rough rolling on the homogenized ingot, the ingot is continuously rolled at a pass reduction of 35-50 mm and a rolling speed of 2.0-5.0 m / s until the second to fourth pass from the last, so that the reduction rate of the subsequent pass is not less than that of the previous pass, and the pass reduction rate is not less than 30%, the rolling speed is controlled within the range of 0.5-3.0 m / s, and the final rolling temperature of the hot rough rolling is controlled to be below 450° C.;

[0013] Step S4: performing hot finish rolling on the hot rough rolled plate to obtain a hot finish rolled plate;

[0014] Step S5: cooling the hot-rolled plate;

[0015] Step S6: The cooled hot-rolled sheet is sequentially subjected to primary cold rolling, intermediate annealing, secondary cold rolling and final annealing to obtain the aluminum alloy sheet.

[0016] Further, based on the total weight of the aluminum alloy plate, the aluminum alloy plate contains the following components in weight percentage: 0.08wt%-0.15wt% of Si, 4.0wt%-5.0wt% of Mg, 0.3wt%-0.4wt% of Mn, 0.2wt%-0.4wt% of Fe, ≤0.15wt% of Cu, ≤0.10wt% of Cr, ≤0.25wt% of Zn, 0.02wt%-0.04wt% of Ti, and the balance of Al and unavoidable impurities.

[0017] Furthermore, step S3 includes: performing hot rough rolling on the homogenized ingot to obtain a hot rough rolled plate, controlling the start rolling temperature of the hot rough rolling within the range of 520-530°C, controlling the number of hot rough rolling passes within the range of 13-19 passes, and during the hot rough rolling process, after performing 3-5 hot rough rolling on the homogenized ingot, continuously rolling to the second to fourth last passes with a pass reduction of 35-50 mm and a rolling speed of 2.0-3.5 m / s, so that the reduction rate of the next pass is not less than the reduction rate of the previous pass, and the pass reduction rate is not less than 30%, the rolling speed is controlled within the range of 0.5-1.5 m / s, and the final rolling temperature of the hot rough rolling is controlled below 450°C.

[0018] Furthermore, in step S2, homogenizing the ingot includes heating the ingot to 420-480°C at a heating rate of 30-60°C / h, keeping the temperature for 4-8h, and then heating the ingot to 520-550°C at a heating rate of 30-60°C / h, and keeping the temperature for 8-12h.

[0019] Furthermore, in step S4, the number of passes of the hot finishing rolling is controlled within the range of 2-5 passes, the pass reduction rate is within the range of 20-50%, the reduction rate of the subsequent pass is not less than the reduction rate of the previous pass, the reduction rate of the last pass is >40%, and the hot finishing rolling outlet temperature is within the range of 270-300°C.

[0020] Furthermore, in step S6, the temperature of the intermediate annealing is controlled within the range of 300-400°C, the duration of the intermediate annealing is within the range of 2-8 hours, the pass reduction rate of the secondary cold rolling is ≥30%, the temperature of the final annealing is within the range of 480-540°C, and the duration of the final annealing is within the range of 10-60 seconds.

[0021] In step S6, the intermediate annealing temperature is controlled within the range of 300-400°C, the intermediate annealing time is within the range of 3-8 hours, the secondary cold rolling pass reduction rate is ≥30%, the final annealing temperature is within the range of 480-540°C, and the final annealing time is within the range of 10-60s.

[0022] Furthermore, the thickness of the hot rough-rolled plate obtained in step S3 is in the range of 20-35 mm.

[0023] Furthermore, the thickness of the hot-finished rolled plate obtained in step S4 is in the range of 4-8 mm.

[0024] Furthermore, after the hot rough rolling in step S3 and the hot finish rolling in step S4, the total deformation of the hot finish rolled plate is greater than 98%.

[0025] Further, in step S3, rough hot rolling the homogenized ingot for 3-5 passes includes rough hot rolling the homogenized ingot for 3-5 passes at a rolling speed of 0.5-3.0 m / s.

[0026] Further, in step S3, rough hot rolling the homogenized ingot for 3-5 passes includes rough hot rolling the homogenized ingot for 3-5 passes at a rolling speed of 0.5-1.5 m / s.

[0027] Furthermore, the number of AlFeMn phases with an equivalent circular diameter of less than 5 μm in the aluminum alloy plate accounts for ≥95%, and the maximum equivalent circular diameter of the AlFeMn phase in the aluminum alloy plate is less than 10 μm.

[0028] According to another aspect of the present invention, there is provided an aluminum alloy plate obtained by the above-described method for preparing the aluminum alloy plate, wherein the elongation A of the aluminum alloy plate is 50 ≥27%.

[0029] By applying the technical solution of the present invention, by strictly controlling process parameters such as the start rolling temperature, hot rough rolling passes, pass reduction, and rolling speed during the hot rough rolling process, the large-sized Fe-containing second phase in the aluminum alloy can be fully crushed and refined, and the size of the Fe-containing second phase in the aluminum alloy plate can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminum alloy, thereby increasing the Fe content in the aluminum alloy plate, which is beneficial to the recycling of the aluminum alloy, making the core and surface structures of the aluminum alloy plate more uniform, and being able to prepare aluminum alloy plates with excellent mechanical properties and formability, shortening the hot rough rolling production cycle, improving production efficiency, and reducing the production cost of the aluminum alloy plate. DETAILED DESCRIPTION

[0030] It should be noted that, unless there is a conflict, the various embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the examples. The following examples are merely illustrative and are not intended to limit the scope of protection of the present invention.

[0031] As described in the background of the present invention, the prior art has a poor effect on crushing the Fe-containing second phase in high-Fe content aluminum alloy plates, resulting in low performance of the aluminum alloy plates. In order to solve the above problems in the prior art, a typical embodiment of the present invention provides a method for preparing an aluminum alloy plate, which, based on the total weight of the aluminum alloy plate, contains the following components in percentage by weight: 0.08wt%-0.20wt% Si, 4.0wt%-5.0wt% Mg, 0.3wt%-0.4wt% Mn, 0.2wt%-0.4wt% Fe, ≤0.15wt% Cu, ≤0.10wt% Cr, ≤0.25wt% Zn, 0.02wt%-0.04wt% Ti, and the balance Al and unavoidable impurities, wherein the content of each impurity is less than 0.05wt%, and the preparation method comprises the following steps:

[0032] Step S1: mixing the components of the aluminum alloy plate according to the above ratio, melting and refining the mixture, and then casting the mixture to form an ingot. The thickness of the ingot is within the range of 500 mm to 650 mm, for example, 520 mm to 630 mm, 540 mm to 610 mm, 560 mm to 590 mm, or 570 mm to 580 mm.

[0033] Step S2: homogenizing the ingot;

[0034] Step S3: The homogenized ingot is subjected to hot rough rolling to obtain a hot rough rolled plate, and the starting rolling temperature of the hot rough rolling is controlled within the range of 520-530°C, for example, 522-528°C, 524-526°C, 532-538°C, 534-536°C, 542-548°C or 544-546°C. In the hot rough rolling process, after the homogenized ingot is subjected to hot rough rolling for 3-5 passes, the hot rough rolling is carried out at a pass reduction of 35-60 mm, for example, 37-48 mm, 39-46 mm, 41-44 mm or 51-54 mm, and a rolling speed of 2.0-5.0 m / s, for example, 2.2-3.3 m / s, 2. The rolling speed is continuously rolled at 4-3.1 m / s, 2.6-2.9 m / s, 2.7-2.8 m / s, 3.7-3.8 m / s or 4.7-4.8 m / s until the second to fourth pass from the last, so that the reduction rate of the subsequent pass is not less than the reduction rate of the previous pass, and the reduction rate of the pass is not less than 30%, and the rolling speed is controlled within the range of 0.5-3.0 m / s, such as 0.7-1.3 m / s, 0.9-1.1 m / s, 1.7-2.3 m / s, 1.9-2.1 m / s, 2.1-2.8 or 2.3-2.6 m / s, and the final rolling temperature of the hot rough rolling is controlled below 450°C;

[0035] Step S4: performing hot finish rolling on the hot rough rolled sheet to obtain a hot finish rolled sheet;

[0036] Step S5: cooling the hot-rolled plate; and

[0037] Step S6: The cooled hot-rolled sheet is sequentially subjected to primary cold rolling, intermediate annealing, secondary cold rolling and final annealing to obtain an aluminum alloy sheet.

[0038] By applying the technical solution of the present invention, by strictly controlling process parameters such as the start rolling temperature, hot rough rolling passes, pass reduction, and rolling speed during the hot rough rolling process, the large-sized Fe-containing second phase in the aluminum alloy can be fully crushed and refined, and the size of the Fe-containing second phase in the aluminum alloy plate can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminum alloy, thereby increasing the Fe content in the aluminum alloy plate, which is beneficial to the recycling of the aluminum alloy, making the core and surface structures of the aluminum alloy plate more uniform, and being able to prepare aluminum alloy plates with excellent mechanical properties and formability, shortening the hot rough rolling production cycle, improving production efficiency, and reducing the production cost of the aluminum alloy plate.

[0039] The preparation method of the aluminum alloy plate of the present invention mainly includes the steps of: melting, homogenization treatment, hot rough rolling and hot finish rolling. By controlling the hot rough rolling process, high-temperature rolling is started during the hot rough rolling process, the number of hot rough rolling passes is reduced, the reduction of the hot rough rolling passes is increased, and high-speed rolling is performed, the large-sized Fe-containing second phase in the high-Fe content aluminum alloy can be fully crushed and refined, thereby reducing the adverse effects of the Fe element on the aluminum alloy, improving production efficiency, and making the core and surface structures of the aluminum alloy plate more uniform. It is possible to prepare a high-Fe content aluminum alloy plate with excellent performance, especially improved formability. For example, a high-Fe content 5182 aluminum alloy plate with performance equivalent to that of a low-Fe content 5182 aluminum alloy plate can be obtained.

[0040] In some embodiments of the present invention, the aluminum alloy plate includes the following components in weight percentage: 0.08wt%-0.15wt% Si, 4.0wt%-5.0wt% Mg, 0.3wt%-0.4wt% Mn, 0.2wt%-0.4wt% Fe, ≤0.15wt% Cu, ≤0.10wt% Cr, ≤0.25wt% Zn, 0.02wt%-0.04wt% Ti, and the balance Al and unavoidable impurities, based on the total weight of the aluminum alloy plate.

[0041] In some embodiments of the present invention, step S3 includes: performing hot rough rolling on the ingot after homogenization treatment to obtain hot rough rolled plate, controlling the starting rolling temperature of the hot rough rolling within the range of 520-530°C, and controlling the number of hot rough rolling passes within the range of 13-19 passes. During the hot rough rolling process, after the ingot after homogenization treatment is hot rough rolled for 3-5 passes, it is continuously rolled with a pass reduction of 35-50 mm and a rolling speed of 2.0-3.5 m / s until the 2nd to 4th pass from the last, so that the reduction rate of the next pass is not less than the reduction rate of the previous pass, and the pass reduction rate is not less than 30%, the rolling speed is controlled within the range of 0.5-1.5 m / s, and the final rolling temperature of the hot rough rolling is controlled below 450°C.

[0042] By strictly controlling process parameters such as the start rolling temperature, hot rough rolling passes, pass reduction, and rolling speed during the hot rough rolling process, the large-sized Fe-containing second phase in the aluminum alloy can be fully crushed and refined, and the size of the Fe-containing second phase in the aluminum alloy plate can be reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminum alloy, thereby increasing the Fe content in the aluminum alloy plate, which is beneficial to the recycling of the aluminum alloy, making the core and surface structures of the aluminum alloy plate more uniform, and being able to prepare aluminum alloy plates with excellent mechanical properties and formability, shortening the hot rough rolling production cycle, improving production efficiency, and reducing the production cost of the aluminum alloy plate.

[0043] In some embodiments of the present invention, in the above-mentioned method for preparing aluminum alloy plates, in step S1, conventional casting equipment in the art can be used for casting, preferably, semi-continuous casting equipment can be used for casting to form an ingot. In some embodiments of the present invention, in the above-mentioned method for preparing aluminum alloy plates, in step S3, the ingot after homogenization treatment is directly removed from the furnace and subjected to hot rough rolling to obtain a hot rough rolled plate. In some embodiments of the present invention, in the above-mentioned method for preparing aluminum alloy plates, in step S4, the hot rough rolled plate can be subjected to continuous hot finish rolling to obtain a hot finish rolled plate.

[0044] In some embodiments of the present invention, in the preparation method of the above-mentioned aluminum alloy plate, in step S2, the ingot is homogenized, including: heating the ingot to 420-480°C, such as 430-470°C, 440-460°C or 445-450°C at a heating rate of 30-60°C / h, such as 35-55°C / h, 40-50°C / h or 38-45°C / h, and keeping it warm for 4-8h, such as 5-7h, and then heating it to 520-550°C, such as 525-545°C, 530-540°C or 535-547°C, at a heating rate of 30-60°C / h, such as 35-55°C / h, 40-50°C / h or 38-45°C / h, and keeping it warm for 8-12h, such as 9-11h or 8-10h. By performing the above-mentioned homogenization treatment on the ingot, the microstructure of the aluminum alloy can be significantly improved, the casting stress can be eliminated, the segregation of the ingot can be reduced, and the quality of the ingot can be significantly improved.

[0045] In some embodiments of the present invention, in the above-mentioned method for preparing an aluminum alloy plate, in step S4, the number of hot finish rolling passes is controlled within a range of 2-5 passes, for example, 3-4 passes, the pass reduction ratio is within a range of 20-50%, for example, 25-45%, 30-40%, or 28-35%, the subsequent pass reduction ratio is not less than the previous pass reduction ratio, the final pass reduction ratio is greater than 40%, and the hot finish rolling outlet temperature is within a range of 270-300° C., for example, 280-290° C. or 275-285° C. By controlling the process parameters during the hot finish rolling process, not only can the AlFeMn phase size and surface quality that meet the final requirements be obtained, but the strength and hardness of the aluminum alloy can also be improved.

[0046] In some embodiments of the present invention, in the above-mentioned method for preparing an aluminum alloy plate, in step S6, the intermediate annealing temperature is controlled within the range of 300-400°C, such as 320-380°C, 340-360°C, or 330-350°C, the intermediate annealing time is within the range of 2-8 hours, such as 2-7 hours or 5-6 hours, the secondary cold rolling pass reduction rate is ≥30%, the final annealing temperature is within the range of 480-540°C, such as 490-530°C, 500-520°C, or 510-535°C, and the final annealing time is within the range of 10-60 seconds, such as 20-50 seconds, 30-40 seconds, or 15-55 seconds. By controlling the intermediate annealing temperature and time, the secondary cold rolling pass reduction rate, and the final annealing temperature and time within the above-mentioned ranges, the mechanical properties and processing properties of the aluminum alloy plate can be improved.

[0047] In some embodiments of the present invention, in step S6, the intermediate annealing temperature is controlled within the range of 300-400°C, the intermediate annealing duration is within the range of 3-8 hours, the secondary cold rolling pass reduction is ≥30%, the final annealing temperature is controlled within the range of 480-540°C, and the final annealing duration is controlled within the range of 10-60 seconds. By controlling the intermediate annealing temperature and duration, the secondary cold rolling pass reduction, and the final annealing temperature and duration within the above ranges, the mechanical properties and processability of the aluminum alloy plate can be further improved.

[0048] In some embodiments of the present invention, in the method for preparing the aluminum alloy plate, cooling, such as water cooling, may be performed after the final annealing.

[0049] In some embodiments of the present invention, in the above-mentioned method for preparing an aluminum alloy plate, in order to prepare an aluminum alloy plate that meets specific application requirements and has high strength, the thickness of the hot rough-rolled plate obtained in step S3 is within the range of 20-35 mm. Specifically, the thickness of the hot rough-rolled plate obtained in step S3 can be within the following ranges: 20-35 mm, 21-34 mm, 22-33 mm, 23-32 mm, 24-31 mm, 25-30 mm, 26-29 mm, or 27-28 mm.

[0050] In some embodiments of the present invention, in the above-mentioned method for preparing an aluminum alloy plate, in order to prepare an aluminum alloy plate that meets specific application requirements and has high strength, the thickness of the hot-rolled plate obtained in step S4 is within the range of 4-8 mm. Specifically, the thickness of the hot-rolled plate obtained in step S4 can be within the following ranges: 4-8 mm, 4.5-7.5 mm, 5-7 mm, 5.5-6.5 mm, or 4-5 mm.

[0051] In some embodiments of the present invention, in the above-mentioned method for preparing an aluminum alloy plate, the total deformation of the hot-finished plate after the hot rough rolling in step S3 and the hot finish rolling in step S4 is greater than 98%. By controlling the total deformation of the hot-finished plate after the hot rough rolling and hot finish rolling within the above-mentioned range, an aluminum alloy plate with excellent mechanical properties and formability can be obtained.

[0052] In some embodiments of the present invention, in the aluminum alloy plate production method, in step S3, subjecting the homogenized ingot to hot rough rolling for 3-5 passes includes subjecting the homogenized ingot to hot rough rolling for 3-5 passes at a rolling speed of 0.5-3.0 m / s. By controlling the rolling speed within the above range, it is possible to ensure that the homogenized ingot is smoothly engaged by the hot rough rolling mill.

[0053] In some embodiments of the present invention, in step S3, rough hot rolling the homogenized ingot for 3-5 passes includes rough hot rolling the homogenized ingot for 3-5 passes at a rolling speed of 0.5-1.5 m / s.

[0054] In some embodiments of the present invention, in the above-described method for preparing an aluminum alloy plate, the percentage of AlFeMn phases with an equivalent circular diameter of 5 μm or less in the aluminum alloy plate is ≥95%, and the maximum equivalent circular diameter of the AlFeMn phases in the aluminum alloy plate is <10 μm. By controlling the percentage of AlFeMn phases with an equivalent circular diameter of 5 μm or less in the aluminum alloy plate and the maximum equivalent circular diameter of the AlFeMn phases in the aluminum alloy plate within the above-described ranges, sufficient crushing and refinement of the Fe-containing secondary phase in the aluminum alloy can be ensured, resulting in an aluminum alloy plate with excellent mechanical properties and formability.

[0055] Another typical embodiment of the present invention provides an aluminum alloy plate obtained by the above-described method for preparing an aluminum alloy plate, wherein the elongation A of the aluminum alloy plate is 50 ≥27%. By controlling the elongation of the aluminum alloy sheet within the above range, it is possible to ensure that the aluminum alloy has excellent formability.

[0056] The present invention achieves sufficient crushing of the Fe-containing second phase in the hot-rolled slab during the production of high-Fe aluminum alloy plates by adjusting the process, such as increasing the hot roughing rolling start temperature, reducing the number of hot roughing passes, increasing the hot roughing pass reduction, and increasing the rolling speed. This allows the production of high-Fe aluminum alloy plates, such as 5182 aluminum alloy plates, for use in automotive interior panels and structural parts. Of course, the uses of the aluminum alloy plates produced by the method of the present invention are not limited thereto and may also be applied to other applications.

[0057] Compared with the prior art, the significant advantages of the preparation method of the aluminum alloy plate in the present invention are mainly reflected in the following aspects:

[0058] The present invention reduces the adverse effects of harmful element Fe on aluminum alloys such as 5182 aluminum alloy, thereby increasing the Fe content in the aluminum alloy, which is beneficial to the recycling of the aluminum alloy.

[0059] The present invention strictly limits the hot rough rolling start temperature. By increasing the hot rough rolling start temperature, the Fe-containing second phase in the aluminum alloy can be more fully crushed. The present invention uses high temperature rolling to achieve the crushing of the Fe-containing second phase, and no additional cooling is required.

[0060] The present invention increases the reduction in the hot rough rolling pass, so that the rolling deformation penetrates into the core of the ingot, thereby causing the Fe-containing second phase (AlFeMn phase) in the ingot to be broken, achieving uniform crushing effect of the Fe-containing second phase on the surface and in the core of the ingot, and significantly reducing the large-sized Fe-containing second phase remaining in the core.

[0061] The process parameters proposed in the present invention, such as the hot rough rolling start temperature, hot rough rolling passes, hot rough rolling pass reduction and rolling speed, can fully crush and refine the Fe-containing second phase in the high-Fe content aluminum alloy, and can meet industrial production conditions without the need for additional equipment.

[0062] The present invention shortens the production cycle of heat treatment and hot rough rolling by adjusting the hot rough rolling start temperature and reducing the number of hot rough rolling passes, thereby improving production efficiency and reducing the production cost of high-Fe content aluminum alloy plates.

[0063] The crushing and refinement of the AlFeMn phase is to improve the formability of the final aluminum alloy plate, etc., to ensure that the Fe element increases during the recycling process of aluminum alloys such as 5182 aluminum alloy, and still maintain excellent application performance.

[0064] The present invention directly starts rolling after homogenization treatment, and compared with the prior art, the present invention has higher production efficiency.

[0065] The present invention uses processes such as high-temperature rolling, reduced number of hot roughing passes, increased reduction in hot roughing passes, and high-speed rolling during the hot roughing process to fully crush the Fe-containing second phase during the hot roughing process, thereby ensuring that the elongation of the finished plate is ≥27%. The performance of the finished plate obtained by the present invention is much higher than that of the finished plate in the prior art.

[0066] The present invention regulates the Mn element content so that the Mn element and the Fe element combine to form the relatively less harmful Al6FeMn phase, thereby reducing the adverse effects of the harmful element Fe. In the present invention, the Ti element can refine the ingot structure and further refine the AlFeMn phase distributed along the grain boundaries.

[0067] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0068] Example 1

[0069] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0070] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, holding for 4h, then controlling the heating rate to 60℃ / h, heating to 530℃, and holding for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 525℃, the hot rough rolling pass was controlled to 19 passes, and after 3 hot rough rolling passes at a rolling speed of 1.5m / s, it was continuously rolled for 13 passes at a pass reduction of 35mm and a rolling speed of 2.0m / s. After each pass, the reduction rate of the subsequent pass is not less than that of the previous pass, and the reduction rate of each pass is not less than 30%. The rolling speed is controlled at 1.5m / s, the final rolling temperature of hot rough rolling is 435℃, and the thickness of the hot rough rolled plate is 23mm. The number of hot finishing rolling passes is 3, and the pass reduction rates are 22%, 33% and 50% respectively. The hot finishing rolling outlet temperature is 285℃, and the thickness of the hot finishing rolled plate is 6mm. The hot rolled plate is obtained, cold rolled to 1.42mm once, the intermediate annealing temperature is 340℃, the holding time is 5h, the secondary cold rolling to 1.0mm, the final annealing temperature is 530℃, the holding time is 60s, and water cooling is used to finally obtain the finished plate.

[0071] Example 2

[0072] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.11wt%, Mg: 4.8wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.04wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0073] The alloy was melted according to the above ratio, and the melt was refined (filtered by a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to be 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to be 60℃ / h, heated to 440℃, and kept warm for 4h, and then the heating rate was controlled to be 60℃ / h, heated to 530℃, and kept warm for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 520℃, the hot rough rolling pass was controlled to be 17 passes, and after 3 hot rough rolling passes at a rolling speed of 1.5m / s, it was continuously rolled at a pass reduction of 40mm and a rolling speed of 2.5m / s. After 11 passes, the reduction rate of the next pass is not less than that of the previous pass, and the reduction rate of each pass is not less than 30%. The rolling speed is controlled at 1.0 m / s, the final rolling temperature of hot rough rolling is 440°C, and the thickness of the hot rough rolled plate is 27 mm. The number of hot finishing rolling passes is 3, and the pass reduction rates are 26%, 40% and 46% respectively. The hot finishing rolling outlet temperature is 290°C, and the thickness of the hot finishing rolled plate is 6 mm. The hot rolled plate is obtained, cold rolled to 1.5 mm once, the intermediate annealing temperature is 300°C, the holding time is 8 h, the secondary cold rolling to 1.0 mm, the final annealing temperature is 520°C, the holding time is 30 s, and water cooling is used to obtain the finished plate.

[0074] Example 3

[0075] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.11wt%, Mg: 4.8wt%, Mn: 0.32wt%, Fe: 0.28wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0076] The alloy was melted according to the above ratio, and the melt was refined (filtered by a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to be 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to be 60℃ / h, heated to 440℃, and kept warm for 4h, and then the heating rate was controlled to be 60℃ / h, heated to 530℃, and kept warm for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 530℃, the hot rough rolling pass was controlled to be 15 passes, and after 3 hot rough rolling passes at a rolling speed of 1.5m / s, it was continuously rolled at a pass reduction of 45mm and a rolling speed of 3.0m / s. After 9 passes, the reduction rate of the next pass is not less than that of the previous pass, and the reduction rate of each pass is not less than 30%. The rolling speed is controlled at 1.0 m / s, the final rolling temperature of hot rough rolling is 440°C, and the thickness of the hot rough rolled plate is 23 mm. The number of hot finishing rolling passes is 3, and the pass reduction rates are 22%, 33% and 50% respectively. The hot finishing rolling outlet temperature is 293°C, and the thickness of the hot finishing rolled plate is 6 mm. The hot rolled plate is obtained, cold rolled to 1.54 mm once, the intermediate annealing temperature is 320°C, the holding time is 6 h, the secondary cold rolling to 1.0 mm, the final annealing temperature is 500°C, the holding time is 45 s, and water cooling is used to obtain the finished plate.

[0077] Example 4

[0078] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 5.0wt%, Mn: 0.34wt%, Fe: 0.30wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.04wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0079] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, keeping warm for 4h, then controlling the heating rate to 60℃ / h, heating to 530℃, and keeping warm for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 526℃, the hot rough rolling pass was controlled to 13 passes, and after 3 hot rough rolling passes at a rolling speed of 1.5m / s, it was continuously rolled for 7 passes at a pass reduction of 50mm and a rolling speed of 3.5m / s. After each pass, the reduction rate of the subsequent pass is not less than that of the previous pass, and the reduction rate of each pass is not less than 30%. The rolling speed is controlled at 1.0 m / s, the final rolling temperature of hot rough rolling is 449°C, and the thickness of the hot rough rolled plate is 25 mm. The number of hot finishing rolling passes is 3, and the pass reduction rates are 28%, 33% and 50% respectively. The hot finishing rolling outlet temperature is 293°C, and the thickness of the hot finishing rolled plate is 6 mm. The hot rolled plate is obtained, cold rolled to 1.62 mm once, the intermediate annealing temperature is 380°C, the holding time is 3.5 h, and the second cold rolling is to 1.0 mm. The final annealing temperature is 520°C, the holding time is 30 s, and water cooling is used to obtain the finished plate.

[0080] Example 5

[0081] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.15wt%, Mg: 5.0wt%, Mn: 0.34wt%, Fe: 0.3wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.04wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0082] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, holding for 4h, then controlling the heating rate to 60℃ / h, heating to 530℃, and holding for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 525℃, the hot rough rolling pass was controlled to 19 passes, and after 3 hot rough rolling passes at a rolling speed of 1.5m / s, it was continuously rolled for 1 pass at a pass reduction of 35mm and a rolling speed of 2.0m / s. After 3 passes, the reduction rate of the next pass is not less than that of the previous pass, and the reduction rate of each pass is not less than 30%. The rolling speed is controlled at 1.5m / s, the final rolling temperature of hot rough rolling is 435℃, and the thickness of hot rough rolled plate is 23mm. The number of hot finishing rolling passes is 3, and the pass reduction rates are 22%, 33% and 50% respectively. The hot finishing rolling outlet temperature is 285℃, and the thickness of hot finishing rolled plate is 6mm. The hot rolled plate is obtained, cold rolled to 1.55mm once, the intermediate annealing temperature is 400℃, the holding time is 3h, the secondary cold rolling to 1.0mm, the final annealing temperature is 490℃, the holding time is 20s, and water cooling is used to obtain the finished plate.

[0083] Comparative Example 1

[0084] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0085] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized. The homogenization process was as follows: heating to 440°C at a rate of 60°C / h and holding for 4h, then heating to 530°C at a rate of 60°C / h and holding for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling. The hot rough rolling start temperature was 525°C, the hot rough rolling pass was controlled to 23 passes, and the maximum pass reduction was 28mm. The maximum rolling speed is 2.0m / s, the hot rough rolling finishing temperature is 448℃, and the thickness of the hot rough rolled plate is 32mm; the number of hot finishing rolling passes is 3, and the pass reduction rates are 25%, 33% and 50% respectively. The hot finishing rolling outlet temperature is 300℃, and the thickness of the hot finishing rolled plate is 8mm. The hot rolled plate is obtained, cold rolled to 1.8mm once, the intermediate annealing temperature is 350℃, the holding time is 5h, and the second cold rolling to 1.0mm, the final annealing temperature is 530℃, the holding time is 30s, and water cooling is used to obtain the finished plate.

[0086] Comparative Example 2

[0087] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0088] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to 60℃ / h, heated to 440℃, and kept warm for 4h, then the heating rate was controlled to 60℃ / h, heated to 530℃, and kept warm for 10h; the ingot was cooled to 490℃ and then hot rough rolling was carried out, the hot rough rolling start temperature was 490℃, the hot rough rolling pass was controlled to 19 passes, the maximum pass reduction was 25mm, and the maximum rolling speed was 1.0m / s, the hot rough rolling finishing temperature is 435℃, the hot rough rolling plate thickness is 27mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 30%, 37% and 50% respectively, the hot finishing rolling outlet temperature is 310℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained, which is cold rolled to 1.5mm once, the intermediate annealing temperature is 340℃, the holding time is 5h, the secondary cold rolling to 1.0mm, the final annealing temperature is 530℃, the holding time is 60s, and water cooling is used to obtain the finished plate.

[0089] Comparative Example 3

[0090] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0091] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to 60℃ / h, heated to 440℃, and kept warm for 4h, then the heating rate was controlled to 60℃ / h, heated to 530℃, and kept warm for 10h; the ingot was cooled to 490℃ and then hot rough rolling was carried out, the hot rough rolling start temperature was 485℃, the hot rough rolling pass was controlled to 23 passes, the maximum pass reduction was 30mm, and the maximum rolling speed was 1 .5m / s, the hot rough rolling finishing temperature is 445℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained, which is cold rolled to 1.52mm once, the intermediate annealing temperature is 370℃, the holding time is 4h, the secondary cold rolling to 1.0mm, the final annealing temperature is 520℃, the holding time is 30s, and water cooling is used to obtain the finished plate.

[0092] Comparative Example 4

[0093] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0094] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to 60℃ / h, heated to 440℃, and kept warm for 4h, then the heating rate was controlled to 60℃ / h, heated to 530℃, and kept warm for 10h; the ingot was cooled to 490℃ and then hot rough rolling was carried out, the hot rough rolling start temperature was 490℃, the hot rough rolling pass was controlled to 27 passes, the maximum pass reduction was 2mm, and the maximum rolling speed was 1. .5m / s, the hot rough rolling finishing temperature is 445℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained, which is cold rolled to 1.45mm for the first time, the intermediate annealing temperature is 360℃, the holding time is 5h, the secondary cold rolling to 1.0mm, the final annealing temperature is 525℃, the holding time is 60s, and water cooling is used to obtain the finished plate.

[0095] Comparative Example 5

[0096] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0097] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, argon degassing online, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled at 60℃ / h, heated to 440℃, and kept warm for 4h, then the heating rate was controlled at 60℃ / h, heated to 530℃, and kept warm for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling, the hot rough rolling start temperature was 515℃, the hot rough rolling pass was controlled to 25 passes, the maximum pass reduction was 25mm, and the maximum pass reduction was 10mm. The maximum rolling speed is 1.0m / s, the hot rough rolling final rolling temperature is 445℃, and the hot rough rolled plate thickness is 25mm; the number of hot finishing rolling passes is 3, and the pass reduction rates are 25%, 29% and 50% respectively. The hot finishing rolling outlet temperature is 305℃, and the hot finishing rolled plate thickness is 6.1mm. The hot rolled plate is obtained, cold rolled to 1.55mm once, the intermediate annealing temperature is 340℃, the holding time is 5h, and the secondary cold rolling is to 1.0mm. The final annealing temperature is 525℃, the holding time is 30s, and water cooling is used to obtain the finished plate.

[0098] Comparative Example 6

[0099] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0100] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: the heating rate was controlled to 60℃ / h, heated to 440℃, and kept warm for 4h, then the heating rate was controlled to 60℃ / h, heated to 530℃, and kept warm for 10h; the ingot was cooled to 490℃ and then hot rough rolling was carried out, the hot rough rolling start temperature was 490℃, the hot rough rolling pass was controlled to 25 passes, the maximum pass reduction was 25mm, and the maximum rolling speed was 3 .0m / s, the hot rough rolling finishing temperature is 445℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6.1mm, and the hot rolled plate is obtained, which is cold rolled to 1.6mm for the first time, the intermediate annealing temperature is 350℃, the holding time is 5h, the secondary cold rolling to 1.0mm, the final annealing temperature is 530℃, the holding time is 30s, and water cooling is used to obtain the finished plate.

[0101] Comparative Example 7

[0102] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0103] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, keeping warm for 4h, then controlling the heating rate to 60℃ / h, heating to 540℃, and keeping warm for 10h; then hot rough rolling was carried out, the hot rough rolling start temperature was 555℃, the hot rough rolling pass was controlled to 25 times, the maximum pass reduction was 25mm, and the maximum rolling speed was 3.0m / h. s, the hot rough rolling finishing temperature is 485℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained. It is cold rolled to 1.5mm once, the intermediate annealing temperature is 340℃, the holding time is 5h, and the secondary cold rolling is to 1.0mm. The final annealing temperature is 525℃, the holding time is 60s, and water cooling is used to obtain the finished plate.

[0104] Comparative Example 8

[0105] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.7wt%, Mn: 0.34wt%, Fe: 0.25wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0106] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized. The homogenization process was as follows: heating to 440°C at a rate of 60°C / h and holding for 4h, then heating to 530°C at a rate of 60°C / h and holding for 10h; the high-Fe content 5182 aluminum alloy ingot after homogenization was directly taken out of the furnace for hot rough rolling. The hot rough rolling start temperature was 515°C, the hot rough rolling pass was controlled to 9 passes, and the maximum pass reduction was 65mm. The maximum rolling speed is 2.5m / s, the hot rough rolling finishing temperature is 485℃, and the thickness of the hot rough rolled plate is 25mm; the number of hot finishing rolling passes is 3, and the pass reduction rates are 25%, 29% and 50% respectively. The hot finishing rolling outlet temperature is 305℃, and the thickness of the hot finishing rolled plate is 6mm. The hot rolled plate is obtained, cold rolled to 1.5mm once, the intermediate annealing temperature is 360℃, the holding time is 4h, and the second cold rolling to 1.0mm, the final annealing temperature is 515℃, the holding time is 60s, and water cooling is used to obtain the finished plate.

[0107] Comparative Example 9

[0108] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.12wt%, Mg: 4.6wt%, Mn: 0.32wt%, Fe: 0.6wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0109] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, keeping warm for 4h, then controlling the heating rate to 60℃ / h, heating to 530℃, and keeping warm for 10h; then hot rough rolling was carried out, the hot rough rolling start temperature was 515℃, the hot rough rolling pass was controlled to 19 passes, the maximum pass reduction was 35mm, and the maximum rolling speed was 2.0m / h. s, the hot rough rolling finishing temperature is 455℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained. It is cold rolled to 1.6mm once, the intermediate annealing temperature is 360℃, the holding time is 3h, and the secondary cold rolling is to 1.0mm. The final annealing temperature is 525℃, the holding time is 30s, and water cooling is used to obtain the finished plate.

[0110] Comparative Example 10

[0111] The aluminum alloy composition is calculated in weight percentage as follows: Si: 0.08wt%, Mg: 4.6wt%, Mn: 0.15wt%, Fe: 0.3wt%, Cu: 0.05wt%, Cr: 0.02wt%, Ti: 0.02wt%, and the remainder is Al and impurities with a content of less than 0.05wt%.

[0112] The alloy was melted according to the above ratio, and the melt was refined (filtered using a 50ppi filter, degassed online with argon, and the hydrogen content was controlled to 0.13ml / 100g Al) and then cast into an ingot with a thickness of 560mm using a semi-continuous casting device; the ingot was head-cut and milled and then homogenized, and the homogenization system was as follows: controlling the heating rate to 60℃ / h, heating to 440℃, keeping warm for 4h, then controlling the heating rate to 60℃ / h, heating to 530℃, and keeping warm for 10h; then hot rough rolling was carried out, the hot rough rolling start temperature was 515℃, the hot rough rolling pass was controlled to 19 passes, the maximum pass reduction was 35mm, and the maximum rolling speed was 2.0m / h. s, the hot rough rolling finishing temperature is 455℃, the hot rough rolling plate thickness is 25mm; the number of hot finishing rolling passes is 3, the pass reduction rates are 25%, 29% and 50% respectively, the hot finishing rolling outlet temperature is 305℃, the hot finishing rolled plate thickness is 6mm, and the hot rolled plate is obtained. It is cold rolled to 1.5mm once, the intermediate annealing temperature is 340℃, the holding time is 5h, and the secondary cold rolling is to 1.0mm. The final annealing temperature is 525℃, the holding time is 60s, and water cooling is used to obtain the finished plate.

[0113] Performance Testing

[0114] Statistics of Fe-containing second phase size:

[0115] For the finished plates obtained in all the embodiments and comparative examples, SEM scanning samples with a sample size of 9 mm × 9 mm were randomly taken. After the samples were mounted and polished, 20 500X photographs were randomly taken on the cross section of the plate thickness direction parallel to the rolling direction using a tungsten filament scanning electron microscope. Sixteen of the photographs were selected and statistically analyzed using Image-Pro Plus 6.0 software to calculate the area and equivalent circular diameter of the Fe-containing second phase, the equivalent circular diameter distribution and the maximum equivalent circular diameter of the Fe-containing second phase, and the percentage of the Fe-containing second phase with an equivalent circular diameter ≤5 μm. The test results are listed in Table 1.

[0116] Mechanical properties test of finished board:

[0117] The elongation (A) of the finished plates obtained in all the embodiments and comparative examples was measured. 50 ), yield strength (R p0.2 ), tensile strength (R s ) test, all test samples were sampled along the vertical rolling direction, and the sample size adopted the A50 tensile specimen recommended by GB / T228. The test results are listed in Table 1.

[0118] Table 1: Performance test results of the embodiments and comparative examples

[0119] As can be seen from Table 1, the percentage (%) of the Fe-containing second phase with an equivalent circular diameter ≤ 5 μm in the finished plates of Examples 1-5 is higher than 95%, the maximum equivalent circular diameter of the Fe-containing second phase is less than 10 μm, and the finished plates of Examples 1-5 have higher elongation, higher yield strength, and higher tensile strength. However, the percentage (%) of the Fe-containing second phase with an equivalent circular diameter ≤ 5 μm in the finished plates of Comparative Examples 1-6 and 9-10 is significantly lower, and the maximum equivalent circular diameter of the Fe-containing second phase is significantly larger. The finished plates of Comparative Examples 1-6 and 9-10 have lower elongation, lower yield strength, and lower tensile strength. Comparative Examples 1-10 do not meet the requirements of the present invention, resulting in the following results:

[0120] In Comparative Example 1, due to the large number of hot rough rolling passes and the small reduction in a single pass, the deformation of the ingot in a single rolling pass is small, and the Fe-containing second phase is not sufficiently crushed, resulting in a larger size of the Fe-containing second phase and a lower elongation of the finished plate.

[0121] In Comparative Example 2, due to the low starting temperature of the hot rough rolling, the Fe-containing second phase was not sufficiently crushed during the rolling process, resulting in a larger size of the Fe-containing second phase and unqualified elongation of the finished plate.

[0122] Compared with Comparative Example 2, Comparative Examples 3 and 4 have more hot rough rolling passes, smaller reduction in a single pass, smaller deformation of the ingot in a single rolling pass, and less sufficient crushing of the Fe-containing second phase, resulting in a larger size of the Fe-containing second phase and unqualified elongation of the finished plate.

[0123] In Comparative Example 5, due to the slow hot rough rolling speed, the deformation of the ingot during rolling was mainly in the surface or sub-surface layer, and the Fe-containing second phase was not sufficiently crushed, resulting in a larger size and unqualified elongation of the finished plate.

[0124] In Comparative Example 6, the starting temperature of the hot rough rolling was low. Although the rolling speed was increased, the Fe-containing second phase was not sufficiently crushed, resulting in a larger size of the Fe-containing second phase and unqualified elongation of the finished plate.

[0125] In Comparative Example 7, the homogenization temperature was too high, and the ingot was over-burned.

[0126] In Comparative Example 8, the single-pass reduction was too large, and the hot roughing mill could not bite in, resulting in the inability to continue rolling.

[0127] In Comparative Example 9, due to the excessively high Fe content, the Fe-containing second phase was too coarse, resulting in poor crushing effect during the hot rough rolling process and unqualified elongation of the finished plate.

[0128] In Comparative Example 10, due to the low Mn content, the Fe element cannot combine with the Mn element to form an easily broken intermetallic compound, resulting in poor crushing effect of the Fe element during the rolling process, and further resulting in unqualified elongation of the finished plate.

[0129] It can be seen from the above performance test results that by strictly controlling the process parameters such as the start rolling temperature, hot rough rolling passes, pass reduction and rolling speed during the hot rough rolling process, the large-sized Fe-containing second phase in the aluminum alloy can be fully crushed and refined, and the size of the Fe-containing second phase in the aluminum alloy plate is reduced, thereby reducing the adverse effects of the harmful element Fe on the aluminum alloy, and further increasing the Fe content in the aluminum alloy plate, which is beneficial to the recycling of the aluminum alloy, can make the core and surface structures of the aluminum alloy plate more uniform, can prepare aluminum alloy plates with excellent mechanical properties and formability, shorten the hot rough rolling production cycle, improve production efficiency, and reduce the production cost of the aluminum alloy plate.

[0130] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum alloy plate, characterized in that: Based on the total weight of the aluminum alloy plate, the aluminum alloy plate comprises the following components by weight percentage: 0.08wt%-0.20wt% of Si, 4.0wt%-5.0wt% of Mg, 0.3wt%-0.4wt% of Mn, 0.2wt%-0.4wt% of Fe, ≤0.15wt% of Cu, ≤0.10wt% of Cr, ≤0.25wt% of Zn, 0.02wt%-0.04wt% of Ti, and the balance of Al and unavoidable impurities, wherein the content of each impurity is less than 0.05wt%, and the preparation method comprises the following steps: Step S1: mixing the components of the aluminum alloy plate according to a proportion, melting and refining the mixture, and then casting the mixture to form an ingot, wherein the thickness of the ingot is in the range of 500 mm to 650 mm; Step S2: homogenizing the ingot; Step S3: performing hot rough rolling on the homogenized ingot to obtain a hot rough rolled plate, controlling the start rolling temperature of the hot rough rolling within the range of 520-550°C, and in the hot rough rolling process, after performing hot rough rolling on the homogenized ingot for 3-5 passes, continuously rolling with a pass reduction of 35-60 mm and a rolling speed of 2.0-5.0 m / s until the second to fourth pass from the last, making the reduction rate of the next pass not less than the reduction rate of the previous pass, making the pass reduction rate not less than 30%, controlling the rolling speed within the range of 0.5-3.0 m / s, and controlling the final rolling temperature of the hot rough rolling below 450°C; Step S4: hot finish rolling the hot rough rolled sheet to obtain a hot finish rolled sheet; Step S5: cooling the hot-rolled plate; and Step S6: The cooled hot-rolled sheet is sequentially subjected to primary cold rolling, intermediate annealing, secondary cold rolling and final annealing to obtain the aluminum alloy sheet.

2. The method for preparing an aluminum alloy plate according to claim 1, characterized in that: The aluminum alloy plate comprises the following components in weight percentage: 0.08wt%-0.15wt% Si, 4.0wt%-5.0wt% Mg, 0.3wt%-0.4wt% Mn, 0.2wt%-0.4wt% Fe, ≤0.15wt% Cu, ≤0.10wt% Cr, ≤0.25wt% Zn, 0.02wt%-0.04wt% Ti, and the balance Al and unavoidable impurities, based on the total weight of the aluminum alloy plate.

3. The method for preparing an aluminum alloy plate according to claim 1, characterized in that: The step S3 comprises: performing hot rough rolling on the homogenized ingot to obtain a hot rough rolled plate, controlling the start rolling temperature of the hot rough rolling within the range of 520-530°C, controlling the number of passes of the hot rough rolling within the range of 13-19 passes, and in the hot rough rolling process, after performing 3-5 passes of hot rough rolling on the homogenized ingot, continuously rolling to the second to fourth passes from the last with a pass reduction of 35-50mm and a rolling speed of 2.0-3.5m / s, so that the reduction rate of the next pass is not less than the reduction rate of the previous pass, and the pass reduction rate is not less than 30%, the rolling speed is controlled within the range of 0.5-1.5m / s, and the final rolling temperature of the hot rough rolling is controlled below 450°C.

4. The method for preparing an aluminum alloy plate according to claim 1, characterized in that: In step S2, homogenizing the ingot includes: heating the ingot to 420-480°C at a heating rate of 30-60°C / h, keeping the temperature for 4-8h, and then heating the ingot to 520-550°C at a heating rate of 30-60°C / h, and keeping the temperature for 8-12h.

5. The method for preparing an aluminum alloy plate according to claim 1, characterized in that: In step S4, the number of hot finishing rolling passes is controlled within the range of 2-5 passes, the pass reduction rate is within the range of 20-50%, the reduction rate of the next pass is not less than the reduction rate of the previous pass, the reduction rate of the last pass is >40%, and the hot finishing rolling outlet temperature is within the range of 270-300°C.

6. The method for preparing an aluminum alloy plate according to any one of claims 1 to 5, characterized in that: In step S6, the temperature of the intermediate annealing is controlled within the range of 300-400°C, the duration of the intermediate annealing is within the range of 2-8h, the pass reduction rate of the secondary cold rolling is ≥30%, the temperature of the final annealing is within the range of 480-540°C, and the duration of the final annealing is within the range of 10-60s.

7. The method for preparing an aluminum alloy plate according to any one of claims 1 to 5, characterized in that: In step S6, the temperature of the intermediate annealing is controlled within the range of 300-400°C, the duration of the intermediate annealing is within the range of 3-8h, the pass reduction rate of the secondary cold rolling is ≥30%, the temperature of the final annealing is within the range of 480-540°C, and the duration of the final annealing is within the range of 10-60s.

8. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: The thickness of the hot rough-rolled plate obtained in step S3 is in the range of 20-35 mm.

9. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: The thickness of the hot-rolled plate obtained in step S4 is in the range of 4-8 mm.

10. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: After the hot rough rolling in step S3 and the hot finish rolling in step S4, the total deformation amount of the hot finish rolled sheet is greater than 98%.

11. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: In step S3, hot rough rolling the homogenized ingot for 3-5 times includes hot rough rolling the homogenized ingot for 3-5 times at a rolling speed of 0.5-3.0 m / s.

12. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: In step S3, hot rough rolling the homogenized ingot for 3-5 times includes hot rough rolling the homogenized ingot for 3-5 times at a rolling speed of 0.5-1.5 m / s.

13. The method for preparing an aluminum alloy plate according to any one of claims 1 to 7, characterized in that: The number of AlFeMn phases with an equivalent circular diameter of less than 5 μm in the aluminum alloy plate accounts for ≥95%, and the maximum equivalent circular diameter of the AlFeMn phase in the aluminum alloy plate is less than 10 μm.

14. An aluminum alloy plate obtained by the method for preparing an aluminum alloy plate according to any one of claims 1 to 13, characterized in that: The elongation A of the aluminum alloy plate 50 ≥27%.

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