Aluminum foil as well as preparation method and application thereof
By controlling the composition and process of aluminum foil, an aluminum foil with both excellent mechanical properties and wettability was prepared, solving the problem that existing aluminum foils could not meet the requirements of aseptic packaging, and achieving efficient and low-cost production and application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINALCO MATERIALS APPL RES INST CO LTD
- Filing Date
- 2026-04-08
- Publication Date
- 2026-05-12
AI Technical Summary
Existing aluminum foils cannot simultaneously possess excellent mechanical properties and wettability, thus failing to meet the high-end requirements of aseptic packaging.
By controlling the contents of Si, Fe, Cu, Mn, Cr, Zn, Ga, and Ti in aluminum foil, and combining casting and cold rolling processes, the grain size and annealing conditions of the aluminum foil can be controlled to prepare aluminum foil with good tensile strength, elongation at break, and wettability.
This technology enables high-performance applications of aluminum foil in aseptic packaging, improving its mechanical properties and wettability, reducing production costs, and increasing production efficiency.
Smart Images
Figure CN122012995A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of aluminum alloy foil and its processing technology, and more specifically, to an aluminum foil, its preparation method and application. Background Technology
[0002] Aseptic packaging is the mainstream packaging method for modern dairy and beverage products, and it is composed of multiple layers of materials such as base paper, aluminum foil, and polyethylene (PE). Aluminum foil has become the core material of aseptic packaging due to its advantages such as low density, moisture and oxygen barrier, non-toxicity and odorlessness, light blocking and heat insulation. Although it accounts for a relatively small proportion of the weight in the composite structure, it bears more than 98% of the oxygen barrier rate and 100% of the light blocking function, which directly determines whether the end product can achieve a shelf life of more than 6 months and the pass rate.
[0003] Aseptic packaging aluminum foil typically has a thickness of 6μm to 7μm and is in the O state. Finished aluminum foil must possess excellent mechanical and wettability properties, ensuring low pinhole and breakage rates. However, existing aluminum foils either have good wettability but low tensile strength and elongation at break, or high tensile strength and elongation at break but poor wettability, resulting in current aseptic packaging aluminum foils failing to fully meet market demands. Summary of the Invention
[0004] The main objective of this application is to provide an aluminum foil, its preparation method, and its application, in order to solve the problem that aluminum foil in the prior art is difficult to have both excellent mechanical properties and wettability.
[0005] To achieve the above objectives, according to a first aspect of this application, an aluminum foil is provided, comprising the following components in weight percentage: Si 0.20%~0.65%, Fe 1.32%~1.60%, Cu 0.12%~0.15%, Mn 0.004%~0.005%, Cr 0~0.002% and not 0, Zn 0~0.01% and not 0, Ga 0~0.012% and not 0, Ti 0~0.018% and not 0, with the remainder being Al and unavoidable impurities.
[0006] Furthermore, the average grain size of the rolled surface of the aluminum foil is <35μm, the transverse (TD, perpendicular to the rolling direction) tensile strength and longitudinal (RD, rolling direction) tensile strength of the aluminum foil are each independently 80MPa~100MPa, the transverse elongation at break and the longitudinal elongation at break of the aluminum foil are each independently 2%~5%, and the wettability of the aluminum foil is above Grade A.
[0007] Furthermore, the thickness of the aluminum foil is 5.5μm~7.0μm.
[0008] According to another aspect of this application, a method for preparing aluminum foil is provided, comprising the following steps:
[0009] S1, prepare aluminum foil blanks with an electrical conductivity of 29.5% IACS~31.5% IACS;
[0010] S2, aluminum foil blank is rolled into aluminum foil to obtain intermediate product;
[0011] S3, the intermediate product is degreased and annealed to obtain aluminum foil;
[0012] The degreasing annealing method is as follows: Heat to T1℃ at a rate of V1℃ / h and hold for t1 h; then heat to T2℃ at a rate of V2℃ / h and hold for t2 h; then heat to T3℃ at a rate of V3℃ / h and hold for t3 h; subsequently cool to T4℃ at a rate of V4℃ / h and hold for t4 h; finally cool to 100℃ at a rate of V5℃ / h and air-cool after removal from the furnace; wherein, V1 is 5~10, T1 is 80~120, t1 is 10~15; V2 is 1~10, T2 is 120~150, t2 is 10~15; V3 is 4~10, T3 is 180~300, t3 is 20~45; V4 is 5~10, T4 is 120~150, t4 is 10~15; V5 is 1~5. T3 is preferably 210~240.
[0013] Furthermore, S1 includes the following steps:
[0014] S11, melt and refine all metal raw materials except Ti to obtain the first melt;
[0015] S12, Ti-containing raw materials are added to the first melt to obtain the second melt; the second melt is then cast and rolled to obtain an aluminum alloy cast and rolled plate;
[0016] S13, cold rolling of aluminum alloy cast and rolled plate to obtain aluminum foil blank.
[0017] Furthermore, in S13, cold rolling includes N passes of cold rolling. After the N-1th pass of cold rolling is completed, the product obtained from the N-1th pass of cold rolling is subjected to intermediate annealing, where N is an integer greater than 1; the intermediate annealing temperature is 200℃~370℃, the intermediate annealing heating rate is 30℃ / h~65℃ / h, and the intermediate annealing holding time is 1.5h~6h.
[0018] Furthermore, the thickness of the aluminum alloy cast-rolled plate is 6mm~8mm.
[0019] Furthermore, the aluminum foil blank is in the H14 state.
[0020] Furthermore, the intermediate product is in the H18 state.
[0021] Furthermore, the thickness of the aluminum foil blank is 0.2mm~0.3mm.
[0022] Furthermore, the thickness of the intermediate product is 5.5 μm to 7.0 μm.
[0023] Furthermore, in S2, the aluminum foil rolling includes M passes of rolling, and after the (M-1)th pass of rolling, the product rolled in the (M-1)th pass is subjected to stress-relief annealing, where M is an integer greater than 1; the stress-relief annealing temperature is ≤180℃.
[0024] Furthermore, T3 is 210℃~240℃.
[0025] Furthermore, in S2, after the aluminum foil is rolled, it is wound up to obtain an intermediate product. The weight of the intermediate product is 0.8 tons to 1.6 tons, and the width of the intermediate product is 1300 mm to 1600 mm.
[0026] According to a third aspect of this application, an application is provided for the aluminum foil prepared by the method of the first aspect of this application or the aluminum foil prepared by the method of the second aspect of this application in the field of aseptic packaging.
[0027] By applying the technical solution in this application, the composition of aluminum foil and the mass percentage of each component can be controlled, which helps to improve the mechanical properties of aluminum foil and ensure that aluminum foil has good wettability. This, in turn, helps to improve the adhesion between aluminum foil and adhesive, and improves the application effect of aluminum foil in the field of aseptic packaging. Attached Figure Description
[0028] Figure 1 This is a microstructure diagram of the rolled surface (TD-RD plane) of the aluminum foil blank in Example 1;
[0029] Figure 2 This is a microstructure diagram of the rolled surface (TD-RD plane) of the aluminum foil in Example 1. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0031] As described in the background section of this application, existing technologies suffer from the problem that aluminum foil cannot simultaneously possess good mechanical properties and wettability. To address this issue, in a typical embodiment of this application, an aluminum foil is provided, comprising the following components by mass percentage: Si 0.20%~0.65%, Fe 1.32%~1.60%, Cu 0.12%~0.15%, Mn 0.004%~0.005%, Cr 0~0.002% and not 0%, Zn 0~0.01% and not 0%, Ga 0~0.012% and not 0%, Ti 0~0.018% and not 0%, with the remainder being Al and unavoidable impurities.
[0032] In the above embodiments of this application, by controlling the content range of each element in the aluminum foil, it is helpful to prepare an aluminum foil blank with an electrical conductivity of 29.5% IACS to 31.5% IACS, ensuring that each element has a moderate solid solubility, which in turn helps to achieve fine grain strengthening and improve the tensile strength and elongation at break of the aluminum foil. Specifically, Si and Fe help form second-phase particles, which act as recrystallization nuclei during annealing, effectively inhibiting abnormal grain growth (PSN mechanism), thus contributing to improved strength and elongation at break of the aluminum foil. Trace amounts of Cu and Mn synergistically refine the microstructure and improve recrystallization stability. Appropriate amounts of Cr help improve the high-temperature dimensional stability of the aluminum alloy, thereby enhancing the strength of the aluminum foil. Appropriate amounts of Zn help improve the wettability of the aluminum foil and enhance the composite adhesion between the aluminum foil and PE layers, etc. Appropriate amounts of Ti help refine the grains and reduce the rolling breakage rate. Furthermore, appropriate amounts of Ga help generate hydrogen fixation in the aluminum alloy, increasing atomic hydrogen and generating combined hydrogen, thereby reducing molecular hydrogen, lowering the porosity of the aluminum foil, and further improving its wettability. The synergistic effect of these elements simultaneously improves the mechanical properties and wettability of the aluminum foil, making it suitable for aseptic packaging applications.
[0033] In some embodiments, the average grain size of the rolled surface of the aluminum foil is <35μm, preferably <15μm; the transverse tensile strength and longitudinal tensile strength of the aluminum foil are each independently 80MPa~100MPa, the transverse elongation at break and the longitudinal elongation at break of the aluminum foil are each independently 2%~5%, and the wettability of the aluminum foil is above Grade A.
[0034] In the above embodiments of this application, controlling the average grain size of the rolled surface of the aluminum foil within the above range helps to balance the tensile strength and elongation at break of the aluminum foil. Controlling the tensile strength, elongation at break, and wettability of the aluminum foil within the above range helps to improve the application effect of aluminum foil in the field of aseptic packaging and meet the application needs of high-end fields.
[0035] In some embodiments, the thickness of the aluminum foil is 5.5 μm to 7.0 μm.
[0036] In the above embodiments of this application, controlling the thickness of the aluminum foil within the above range helps to suppress the formation of pinholes caused by rolling stress concentration in the ultra-thin state, helps to improve the processing performance of the aluminum foil, reduces the risk of strip breakage, and at the same time ensures that the aluminum foil has excellent dimensional stability and interface adhesion when it is laminated with packaging materials such as plastic film, and fully utilizes its oxygen barrier and light-blocking properties.
[0037] In another typical embodiment of this application, a method for preparing aluminum foil is provided, comprising the following steps:
[0038] S1, prepare aluminum foil blanks with an electrical conductivity of 29.5% IACS~31.5% IACS;
[0039] S2, aluminum foil blank is rolled into aluminum foil to obtain intermediate product;
[0040] S3, the intermediate product is degreased and annealed to obtain the aluminum foil;
[0041] The degreasing annealing method is as follows: Heat to T1℃ at a rate of V1℃ / h and hold for t1 h; then heat to T2℃ at a rate of V2℃ / h and hold for t2 h; then heat to T3℃ at a rate of V3℃ / h and hold for t3 h; subsequently cool to T4℃ at a rate of V4℃ / h and hold for t4 h; finally cool to 100℃ at a rate of V5℃ / h and air-cool after removal from the furnace; wherein, V1 is 5~10, T1 is 80~120, t1 is 10~15; V2 is 1~10, T2 is 120~150, t2 is 10~15; V3 is 4~10, T3 is 180~300, t3 is 20~45; V4 is 5~10, T4 is 120~150, t4 is 10~15; V5 is 1~5. T3 is preferably 210~240.
[0042] Currently, the annealing method for aluminum foil is usually determined based on experience. This involves annealing the rolled aluminum foil under different annealing conditions, then conducting transverse and longitudinal tensile tests to obtain the tensile strength and elongation at break of the material. At the same time, the surface of the aluminum foil is sprayed or brushed with water to evaluate its wettability. By balancing the mechanical properties and wettability indicators, the annealing method corresponding to the aluminum foil under this balance is finally determined. The existing method is a post-control method, which requires control of key performance indicators of the product at the finished product process. This method has high testing and production costs and affects the production efficiency of aseptic packaging aluminum foil products.
[0043] In the above embodiments of this application, by controlling the electrical conductivity of the aluminum foil blank in advance, that is, by controlling the microstructure of the aluminum foil blank, such as the quantity and size of the second phase and the solid solubility of alloying elements in the solid solution, it is helpful to determine the processing conditions of the aluminum foil blank in advance, thereby helping to improve production efficiency, save production costs, and prepare aluminum foil with good tensile strength, elongation at break, and wettability. In the above embodiments of this application, a four-probe tester is used to measure the electrical conductivity of the aluminum foil blank. By optimizing the degreasing annealing method, on the one hand, it helps to improve the mechanical properties of the aluminum foil, so that the aluminum foil has good tensile strength and elongation at break; on the other hand, it helps to fully degrease the intermediate product with a weight of 0.8 tons to 1.6 tons and a width of 1300 mm to 1600 mm, further improving the wettability of the aluminum foil; in addition, controlling the degreasing annealing conditions within the above range also helps to improve production efficiency and economic benefits.
[0044] In some implementations, S1 includes the following steps:
[0045] S11, melt and refine all metal raw materials except Ti to obtain the first melt;
[0046] S12, Ti-containing raw materials are added to the first melt to obtain the second melt; the second melt is then cast and rolled to obtain an aluminum alloy cast and rolled plate;
[0047] S13, cold rolling of aluminum alloy cast and rolled plate to obtain aluminum foil blank.
[0048] In the embodiments described above in this application, melting and refining help to prepare a first melt with uniform composition and few impurities, thereby helping to improve the mechanical properties and wettability of the aluminum foil. The casting-rolling method eliminates the hot rolling step, enabling continuous coil production, significantly shortening the production process, reducing production costs, and improving production efficiency; the combination of casting-rolling and cold rolling helps to refine the grains and improve the strength and toughness of the finished aluminum foil.
[0049] Specifically, but not restrictively, refining includes degassing and filtration.
[0050] In some embodiments, in S13, cold rolling includes N passes of cold rolling, and after the N-1th pass of cold rolling, the product obtained from the N-1th pass of cold rolling is subjected to intermediate annealing, where N is an integer greater than 1; the intermediate annealing temperature is 200℃~370℃, the intermediate annealing heating rate is 30℃ / h~65℃ / h, and the intermediate annealing holding time is 1.5h~6h.
[0051] In the above embodiments of this application, controlling the intermediate annealing conditions within the aforementioned range helps to restore the plasticity of the aluminum foil blank, reduce its hardness, and improve its subsequent processing performance. Performing a cold rolling pass after intermediate annealing helps to precisely control the dimensions of the aluminum foil blank. In addition, it also helps to achieve uniform microstructure, improve the uniformity of aluminum foil thickness, and reduce the scrap rate. Furthermore, it helps to remove stress during the cold rolling process and precisely control the electrical conductivity of the aluminum foil blank within the range of 29.5% IACS to 31.5% IACS, thereby helping to reduce the grain size of the aluminum foil, achieve fine grain strengthening, and enable the aluminum foil to have good tensile strength, elongation at break, and wettability.
[0052] In some implementations, the thickness of the aluminum alloy cast-rolled sheet is 6mm to 8mm.
[0053] In the above embodiments of this application, controlling the thickness of the aluminum alloy cast-rolled plate within the above range helps to control the cooling rate, allowing strengthening elements such as Fe and Si to precipitate, which in turn helps to promote grain refinement during subsequent processing and improve the overall performance of the aluminum foil. In addition, controlling the thickness within the above range also helps to improve processing performance, ensuring that the aluminum alloy cast-rolled plate has a smooth surface, dense internal structure, and no pores, which in turn helps to improve the wettability of the aluminum foil.
[0054] In some embodiments, the aluminum foil blank is in the H14 state.
[0055] In the above embodiments of this application, controlling the state of the aluminum foil blank to H14 helps to balance strength and processing performance, providing a basic material with uniform structure and moderate plasticity for subsequent rolling, thereby helping to improve the mechanical properties of the aluminum foil.
[0056] In some implementations, the intermediate product is in the H18 state.
[0057] In the above embodiments of this application, controlling the state of the intermediate product to the H18 state helps to maximize the strength of the aluminum foil, while subsequent degreasing and annealing helps to give the aluminum foil appropriate ductility, improving its application in the field of aseptic packaging.
[0058] In some embodiments, the thickness of the aluminum foil blank is 0.2 mm to 0.3 mm.
[0059] In the above embodiments of this application, controlling the thickness of the aluminum foil blank within the above range helps to reduce residual stress and control the electrical conductivity of the aluminum foil blank within a suitable range, thereby helping to truly reflect the solid solution state of the alloying elements and the content and size of the second phase, and further helping to accurately control the preparation conditions of the aluminum foil, improve processing efficiency, and reduce production costs.
[0060] In some embodiments, the thickness of the intermediate product is 5.5 μm to 7.0 μm.
[0061] In the above embodiments of this application, the thickness of the intermediate product is similar to the thickness of the aluminum foil. Adjusting the thickness of the intermediate product within the above range also controls the thickness of the aluminum foil within the above range. Aluminum foil with the above thickness has high practical value. On the one hand, it has good processing performance and is not easy to break; on the other hand, it has good oxygen barrier, light shielding and low pinhole rate, which can maximize its value while minimizing the amount of aluminum material used.
[0062] In some embodiments, in S2, the aluminum foil rolling is carried out in 3 to 4 passes, with a deformation of 35% to 60% (thickness change rate) in each pass, and the last pass is rolled using a double-rolling method.
[0063] In the above embodiments of this application, controlling the aluminum foil rolling conditions within the above range helps to obtain intermediate products with uniform thickness and composition, and helps to improve the surface finish of the intermediate products, thereby helping to simultaneously improve the mechanical properties and wettability of the aluminum foil and enhance the performance of the aluminum foil.
[0064] In some embodiments, in S2, the aluminum foil rolling includes 3 to 4 rolling passes, and after the penultimate rolling pass, the product rolled in that pass is subjected to stress-relief annealing; the stress-relief annealing temperature is ≤180°C.
[0065] In the above embodiments of this application, stress-relief annealing helps to remove stress during the aluminum foil rolling process, reduce the number of defects in the intermediate product, and thus help to improve the mechanical properties and wettability of the aluminum foil.
[0066] In another typical embodiment of this application, the application of the aluminum foil described in the above embodiments of this application or the aluminum foil prepared by the methods described in the above embodiments of this application is provided in the field of aseptic packaging. Because the aluminum foil described above has good mechanical properties and wettability, it is suitable for use in the field of aseptic packaging.
[0067] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.
[0068] Example 1
[0069] One embodiment of the aluminum foil of this application, the method for preparing the aluminum foil of this embodiment is as follows:
[0070] S1. Raw materials Si, Fe, Cu, Mn, Cr, Zn, and Ga were weighed according to the mass fraction of each element in the aluminum foil. The raw materials were melted and refined, and a titanium-boron refining agent was added. Then, the mixture was cast and rolled to obtain an aluminum alloy cast-rolled plate with a thickness of 6.0 mm. Subsequently, the aluminum alloy cast-rolled plate underwent five cold rolling passes. The thicknesses after the first to fifth cold rolling passes were 4.2 mm, 2.5 mm, 1.1 mm, 0.5 mm, and 0.24 mm, respectively, resulting in an aluminum foil blank with a thickness of 0.24 mm. Intermediate annealing was performed after the fourth cold rolling pass at a temperature of 310℃, a heating rate of 55℃ / h, and a holding time of 5h. The rolled surface of the aluminum foil blank exhibited an elongated equiaxed crystal structure. The electrical conductivity of the aluminum foil blank, measured using a four-probe tester, was 31.5% IACS. The composition of the aluminum foil blank was as follows: Si 0.28%, Fe 1.32%, Cu... 0.12%, Mn 0.004%, Cr 0.0018%, Zn 0.009%, Ga 0.011%, Ti 0.017%, with the remainder being Al and unavoidable impurities;
[0071] S2 uses a double-rolling method to roll aluminum foil blanks in four passes, rolling the thickness from 0.24mm to 0.12mm, 0.05mm, 0.018mm and 0.0063mm respectively, to obtain an intermediate product; the intermediate product is a roll with a width of 1550mm and a weight of 1.5 tons.
[0072] S3. The intermediate product was subjected to degreasing annealing under the following conditions: The temperature was increased from room temperature (25°C) to 80°C at a rate of 5.5°C / h and held for 10 hours; then increased to 120°C at a rate of 8°C / h and held for 10 hours; then increased to 210°C at a rate of 9°C / h and held for 20 hours; subsequently decreased to 120°C at a rate of 9°C / min and held for 10 hours; finally, cooled to 100°C at a rate of 1.5°C / h and air-cooled to obtain the aluminum foil described in this embodiment. Scanning electron backscatter diffraction (EBSD) analysis showed that the surface of the aluminum foil in this embodiment exhibited a fully recrystallized structure.
[0073] Example 2
[0074] One embodiment of the aluminum foil of this application, the method for preparing the aluminum foil of this embodiment is as follows:
[0075] S1. Raw materials Si, Fe, Cu, Mn, Cr, Zn, and Ga were weighed according to the mass fraction of each element in the aluminum foil. The raw materials were melted and refined, and a titanium-boron refining agent was added. Then, the mixture was cast and rolled to obtain an aluminum alloy cast-rolled plate with a thickness of 6.5 mm. Subsequently, the aluminum alloy cast-rolled plate underwent five cold rolling passes. After the fourth cold rolling pass, intermediate annealing was performed at a temperature of 240℃, a heating rate of 50℃ / h, and a holding time of 4h. A final cold rolling pass was then performed to obtain an aluminum foil blank with a thickness of 0.22 mm. The rolled surface of the aluminum foil blank exhibited an elongated equiaxed grain structure. The electrical conductivity of the aluminum foil blank, measured using a four-probe tester, was 29.5% IACS. The composition of the aluminum foil blank was: Si 0.35%, Fe 1.4%, Cu 0.15%, Mn 0.005%, Cr 0.002%, Zn 0.01%, Ga 0.012%, Ti 0.018%, the remainder being Al and unavoidable impurities.
[0076] S2 uses a double-rolling method to roll aluminum foil blanks in four passes, with the thickness rolled from 0.22mm to 0.11mm, 0.052mm, 0.017mm and 0.006mm respectively, to obtain an intermediate product; the intermediate product is a roll with a width of 1500mm and a weight of 1 ton.
[0077] S3. The intermediate product was subjected to degreasing annealing under the following conditions: the temperature was increased from room temperature (25°C) to 120°C at a rate of 4.5°C / h and held for 15 hours; then the temperature was increased to 150°C at a rate of 1.5°C / h and held for 15 hours; then the temperature was increased to 240°C at a rate of 4.5°C / h and held for 45 hours; then the temperature was decreased to 150°C at a rate of 6°C / min and held for 15 hours; finally, the temperature was cooled to 100°C at a rate of 2°C / h, and the product was removed from the furnace and air-cooled to obtain the aluminum foil described in this embodiment. Scanning electron backscatter diffraction (EBSD) analysis showed that the surface of the aluminum foil described in this embodiment exhibited a fully recrystallized structure.
[0078] Example 3
[0079] One embodiment of the aluminum foil of this application, the method for preparing the aluminum foil of this embodiment is as follows:
[0080] S1. Raw materials Si, Fe, Cu, Mn, Cr, Zn, and Ga were weighed according to the mass fraction of each element in the aluminum foil. The raw materials were melted and refined, and a titanium-boron refining agent was added. Then, the mixture was cast and rolled to obtain an aluminum alloy cast-rolled plate with a thickness of 8 mm. Subsequently, the aluminum alloy cast-rolled plate underwent five cold rolling passes. After the fourth cold rolling pass, intermediate annealing was performed at a temperature of 300℃, a heating rate of 50℃ / h, and a holding time of 4h. A final cold rolling pass was then performed to obtain an aluminum foil blank with a thickness of 0.22 mm. The rolled surface of the aluminum foil blank exhibited an elongated equiaxed grain structure. The electrical conductivity of the aluminum foil blank, measured using a four-probe tester, was 30.2% IACS. The composition of the aluminum foil blank was: Si 0.65%, Fe 1.4%, Cu 0.13%, Mn 0.005%, Cr 0.001%, Zn 0.008%, Ga 0.01%, Ti 0.015%, the remainder being Al and unavoidable impurities;
[0081] S2 uses a double-rolling method to roll aluminum foil blanks in four passes, rolling the thickness from 0.22mm to 0.11mm, 0.052mm, 0.017mm and 0.006mm respectively, to obtain an intermediate product; the intermediate product is a roll with a width of 1570mm and a weight of 1.6 tons.
[0082] S3. The intermediate product was subjected to degreasing annealing under the following conditions: The temperature was increased from room temperature (25°C) to 100°C at a rate of 5°C / h and held for 12 hours; then increased to 130°C at a rate of 2°C / h and held for 12 hours; then increased to 230°C at a rate of 5°C / h and held for 30 hours; subsequently decreased to 130°C at a rate of 6°C / min and held for 12 hours; finally, cooled to 100°C at a rate of 2°C / h and air-cooled to obtain the aluminum foil described in this embodiment. Scanning electron backscatter diffraction (EBSD) analysis showed that the surface of the aluminum foil in this embodiment exhibited a fully recrystallized structure.
[0083] Example 4
[0084] One embodiment of the aluminum foil of this application, the preparation method of the aluminum foil in this embodiment is as follows, the only difference from that of Embodiment 1 is:
[0085] In S3, 180℃ is used instead of 210℃.
[0086] Example 5
[0087] One embodiment of the aluminum foil of this application, the preparation method of the aluminum foil in this embodiment is as follows, the only difference from that in Embodiment 2 is:
[0088] In S3, 300℃ is used instead of 240℃.
[0089] Comparative Example 1
[0090] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 lies only in:
[0091] In S1, the intermediate annealing temperature is replaced by 380℃ instead of 310℃, and the grain coarsening results in an electrical conductivity of 32.1% IACS for the aluminum foil blank.
[0092] Comparative Example 2
[0093] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 2 lies only in:
[0094] In S1, the intermediate annealing temperature was replaced with 180℃ instead of 240℃, resulting in incomplete recrystallization of the billet. Consequently, the electrical conductivity of the aluminum foil billet was 29.3% IACS.
[0095] Comparative Example 3
[0096] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 is as follows:
[0097] In S1, the raw materials are weighed out with a Fe mass fraction of 1.2%.
[0098] Comparative Example 4
[0099] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 is as follows:
[0100] In S1, raw materials are weighed with a Si mass fraction of 0.8%.
[0101] Comparative Example 5
[0102] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 is as follows:
[0103] In S1, the mass fraction of Ti is 0.24%.
[0104] Comparative Example 6
[0105] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 is as follows:
[0106] In S3, the holding time in "heat up to 210℃ at a rate of 9℃ / h and hold for 20h" is changed to 10h.
[0107] Comparative Example 7
[0108] This application provides a comparative example of aluminum foil, the difference between the preparation method of the aluminum foil described in this comparative example and that of Example 1 lies only in:
[0109] In S3, the intermediate product is subjected to degreasing annealing under the following conditions: the temperature is increased from room temperature (25°C) to 80°C at a rate of 5.5°C / h and held for 10h; then the temperature is increased to 210°C at a rate of 9°C / h and held for 35h; then the temperature is decreased to 120°C at a rate of 9°C / min and held for 10h; finally, the temperature is cooled to 100°C at a rate of 1.5°C / h and then air-cooled to obtain the aluminum foil described in this comparative example.
[0110] Performance testing
[0111] The properties of the aluminum foil blanks and aluminum foils in the examples and comparative examples were tested. The test methods are as follows, and the test results are shown in Table 1.
[0112] (1) The conductivity of the aluminum foil blank was tested using a four-probe tester;
[0113] (2) The microstructure of the aluminum foil was tested and analyzed using scanning electron microscopy with electron backscatter diffraction. Figure 1 The image shows the microstructure of the rolled surface (TD-RD plane) of the aluminum foil blank in Example 1. The average grain size of the rolled surface was measured to be 30.3 μm. Figure 2 The image shows the microstructure of the rolled surface (TD-RD plane) of the aluminum foil in Example 1. The average grain size of the rolled surface was measured to be 9.74 μm.
[0114] (3) Tensile strength and elongation at break of aluminum foil: Refer to GB / T 22638.11-2023 "Test Methods for Aluminum Foil Part 11: Test of Mechanical Properties" to test the transverse tensile strength, longitudinal tensile strength, transverse elongation at break and longitudinal elongation at break of aluminum foil.
[0115] (4) Wetting properties of aluminum foil: The wettability of both sides of aluminum foil was tested by wiping in GB / T 22638.5-2016 "Test Methods for Aluminum Foil Part 5: Test for Wetting Properties".
[0116] Table 1
[0117]
[0118] As shown in Table 1, the aluminum foils in the embodiments of this application all have good transverse tensile strength (above 80MPa), longitudinal tensile strength (80MPa), transverse elongation at break (above 2%), and longitudinal elongation at break (above 2%), and their wettability can all reach Grade A. They have both good mechanical properties and wettability, and are suitable for use in the field of aseptic packaging.
[0119] In Comparative Examples 1 and 2, the electrical conductivity of the aluminum foil blanks was too high and too low, respectively, making it difficult to achieve both good mechanical properties and elongation at break.
[0120] In Comparative Example 3, the Fe content was too low, resulting in relatively low strength of the aluminum foil. In Comparative Example 4, the Si content was too high, leading to poor ductility and relatively low elongation at break of the aluminum foil. In Comparative Example 5, the Ti content was too high, which easily caused local Ti aggregation, increasing the pinhole rate and reducing the mechanical properties and wettability of the aluminum foil. In Comparative Example 6, the holding time in the high-temperature section of the degreasing annealing was too short, resulting in poor wettability of the aluminum foil. In Comparative Example 7, the degreasing annealing process was missing a step, resulting in poor degreasing effect and poor wettability of the aluminum foil.
[0121] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. An aluminum foil, characterized in that, The aluminum foil comprises the following components by mass percentage: Si 0.20%~0.65%, Fe 1.32%~1.60%, Cu 0.12%~0.15%, Mn 0.004%~0.005%, Cr 0~0.002% and not 0, Zn 0~0.01% and not 0, Ga 0~0.012% and not 0, Ti 0~0.018% and not 0, with the remainder being Al and unavoidable impurities.
2. The aluminum foil according to claim 1, characterized in that, The average grain size of the rolled surface of the aluminum foil is <35μm, the transverse tensile strength and longitudinal tensile strength of the aluminum foil are each independently 80MPa~100MPa, the transverse elongation at break and the longitudinal elongation at break of the aluminum foil are each independently 2%~5%, and the wettability of the aluminum foil is above Grade A.
3. The aluminum foil according to claim 1 or 2, characterized in that, The thickness of the aluminum foil is 5.5μm to 7.0μm.
4. A method for preparing aluminum foil according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1, prepare aluminum foil blanks with an electrical conductivity of 29.5% IACS~31.5% IACS; S2, the aluminum foil blank is rolled into aluminum foil to obtain an intermediate product; S3, the intermediate product is degreased and annealed to obtain the aluminum foil; The degreasing annealing method is as follows: heat up to T1℃ at a rate of V1℃ / h and hold for t1 h; then heat up to T2℃ at a rate of V2℃ / h and hold for t2 h; then heat up to T3℃ at a rate of V3℃ / h and hold for t3 h; then cool down to T4℃ at a rate of V4℃ / h and hold for t4 h; finally cool down to 100℃ at a rate of V5℃ / h and air cool after removal from the furnace. Wherein, V1 is 5~10, T1 is 80~120, t1 is 10~15; V2 is 1~10, T2 is 120~150, t2 is 10~15; V3 is 4~10, T3 is 180~300, t3 is 20~45; V4 is 5~10, T4 is 120~150, t4 is 10~15; V5 is 1~5.
5. The method for preparing aluminum foil according to claim 4, characterized in that, S1 includes the following steps: S11, melt and refine all metal raw materials except Ti to obtain the first melt; S12, add Ti-containing raw materials to the first melt to obtain a second melt; cast and roll the second melt to obtain an aluminum alloy cast and rolled plate; S13, the aluminum alloy cast and rolled plate is cold rolled to obtain the aluminum foil blank.
6. The method for preparing aluminum foil according to claim 5, characterized in that, At least one of the following conditions must be met: (1) In S13, the cold rolling includes N passes of cold rolling, and after the N-1th pass of cold rolling, the product obtained from the N-1th pass of cold rolling is subjected to intermediate annealing; wherein, N is an integer greater than 1; the temperature of the intermediate annealing is 200℃~370℃, the heating rate of the intermediate annealing is 30℃ / h~65℃ / h, and the holding time of the intermediate annealing is 1.5h~6h; (2) The thickness of the aluminum alloy cast and rolled plate is 6mm~8mm.
7. The method for preparing aluminum foil according to any one of claims 4 to 6, characterized in that, At least one of the following conditions must be met: (1) The aluminum foil blank is in the H14 state; (2) The intermediate product is in the H18 state; (3) The thickness of the aluminum foil blank is 0.2mm~0.3mm; (4) The thickness of the intermediate product is 5.5 μm to 7.0 μm.
8. The method for preparing aluminum foil according to any one of claims 4 to 6, characterized in that, In step S2, the aluminum foil rolling includes M passes of rolling, and after the (M-1)th pass of rolling, the product rolled in the (M-1)th pass is subjected to stress-relief annealing; wherein, M is an integer greater than 1; the stress-relief annealing temperature is ≤180℃.
9. The method for preparing aluminum foil according to any one of claims 4 to 6, characterized in that, At least one of the following conditions must be met: (1) The T3 is 210℃~240℃; (2) In S2, after the aluminum foil is rolled, it is wound up to obtain the intermediate product. The weight of the intermediate product is 0.8 tons to 1.6 tons and the width of the intermediate product is 1300 mm to 1600 mm.
10. The application of an aluminum foil according to any one of claims 1 to 3, or an aluminum foil prepared by the method of any one of claims 4 to 9, in the field of aseptic packaging.