Aluminum alloy plate for attenuation-resistant ultrathin can cover material and preparation method of aluminum alloy plate
By adjusting the aluminum alloy composition and process flow, an ultra-thin aluminum alloy sheet for can lids with resistance to degradation was prepared, solving the problem of performance degradation of easy-open can lids during processing and use, and achieving high pressure resistance and low-cost production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-03-13
AI Technical Summary
The existing 5,182 can lid materials have performance degradation issues during processing and use, affecting the pressure resistance of the cans, and are difficult to separate, recycle, and remanufacture into cans.
By adjusting the ratio of strengthening elements such as Cu, Mn, Mg, and Cr, and using a high proportion of scrap aluminum and refining methods, an aluminum alloy sheet for ultra-thin can lids with resistance to degradation is prepared. The process includes steps such as melting, stirring, refining, casting, hot rolling, and cold rolling to optimize the microstructure.
This invention achieves high pressure resistance and low attenuation in easy-open can lid materials, reducing production costs and improving the mechanical properties and economic benefits of the materials.
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Figure CN121653479A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an aluminum alloy sheet for use in ultra-thin can lids with resistance to attenuation and its preparation method, and relates to the field of aluminum alloy technology. Background Technology
[0002] The 5182 can lid material is processed in an H48 state with a cold rolling rate exceeding 90%, resulting in extreme work hardening. Significant performance degradation occurs during coating baking and natural storage, affecting the pressure resistance of the can during service. The current mainstream thickness of 5182 alloy can lid material is 0.218-0.224mm, with a trend towards 0.208mm. The international market has begun developing even thinner 0.203mm can lid materials. The pressure resistance degradation during the process of reducing the thickness of the lid for lightweighting will be one of the key parameters for downstream customers. Therefore, there is an urgent need to develop an aluminum alloy for can lids with high mechanical properties and resistance to performance degradation. Summary of the Invention
[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide an aluminum alloy sheet for resistant to decay and a method for preparing the same, so as to solve the problem that the aluminum alloy composition of the can lid and the can body is different, making it difficult to separate and recycle them and thus impossible to remake the can.
[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: an aluminum alloy sheet for use in ultra-thin can lids with resistance to attenuation, wherein, by mass percentage, the aluminum alloy sheet for can lids comprises the following elements: 0.07~0.15% Si; 0.15~0.3% Fe; 0.07~0.15% Cu; 0.3~0.5% Mn; 4.75~4.95% Mg; 0.01~0.03% Ti; 0.02~0.10% Cr; 0.01~0.20% Zn; the total content of unavoidable impurities is ≤0.15%, and the balance is Al; the sum of the mass of Mn and Cr in the aluminum alloy sheet for can lids is 0.40~0.55%.
[0005] Preferably, the aluminum alloy sheet used for the can lid has a tensile strength of 430~470MPa, a yield strength of 410~440MPa, and an elongation of 6~8%.
[0006] Preferably, the aluminum alloy sheet for can lid material with a coating for easy-open can lid has a tensile strength of 400~420MPa, a yield strength of 350~370MPa, and an elongation of 7~10%.
[0007] Preferably, the aluminum alloy sheet used for the can lid is 0.200-0.208mm thick, and the 202 series two-piece easy-open can lid made from it has a pressure resistance ≥740KPa, an aging pressure resistance ≥700KPa after forced attenuation by boiling in water at 90℃ for 40min, and an attenuation range ≤30KPa.
[0008] A method for preparing an aluminum alloy sheet for use in can lids with resistance to attenuation includes the following steps: raw materials including aluminum ingots, aluminum can scrap, intermediate alloys and metal additives are batched and then sequentially melted, stirred, first refined, first slag removal, second refined, second slag removal, inert gas refining, settling, casting, ingot heating, hot rolling and cold rolling to obtain the aluminum alloy sheet for can lids.
[0009] Preferably, the aluminum can waste is selected from any one or more of 1XXX series aluminum alloys, 3XXX series aluminum alloys, and 5XXX series aluminum alloys; the mass percentage of aluminum can waste in the raw materials is 30-75%.
[0010] Preferably, the melting furnace gas temperature is 1100~1150℃, and the metal melting is carried out under full oxygen combustion conditions.
[0011] Preferably, the amount of refining agent used in the first refining is 0.05~0.3% to remove the oxide slag of aluminum and magnesium metals in the aluminum alloy melt; the amount of refining agent used in the second refining is 0.05~0.3% to remove the alkali metals Na and Ca and various oxide inclusions in the aluminum alloy melt.
[0012] Preferably, the casting process includes: using an online degassing and slag removal device to sequentially degas and filter, then adding a grain refiner to perform the casting, resulting in an ingot with a thickness of 560~620mm; wherein the casting temperature is 690~710℃.
[0013] Preferably, the ingot heating temperature is 490~510℃, and the holding time is 3~8h; the initial rolling temperature of the hot rolling is 490~510℃, the final rolling temperature of the hot rolling is 320~340℃, and the thickness of the aluminum alloy after hot rolling is 2.3~3mm; the total processing rate of the cold rolling is 90~94%; and the coiling temperature of the finished product pass of the cold rolling is 110~140℃.
[0014] Compared with the prior art, the present invention has the following beneficial effects: By adjusting the proportions of strengthening elements such as Cu, Mn, Mg, and Cr, an aluminum alloy for easy-open can lids with high mechanical properties and resistance to degradation has been developed. Furthermore, the can lid of this application exhibits high pressure resistance and utilizes a high proportion of scrap aluminum and a corresponding melt refining method, thereby reducing production costs and demonstrating good practical performance and economic benefits.
[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0016] Figure 1 This is a comparison chart of the amount of slag used in primary refining and secondary refining in an embodiment of the present invention. Detailed Implementation
[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0018] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0020] like Figure 1 As shown, this embodiment provides an aluminum alloy sheet for ultra-thin can lids with resistance to attenuation. By mass percentage, the aluminum alloy sheet for can lids comprises the following elements: 0.07~0.15% Si; 0.15~0.3% Fe; 0.07~0.15% Cu; 0.3~0.5% Mn; 4.75~4.95% Mg; 0.01~0.03% Ti; 0.02~0.10% Cr; 0.01~0.20% Zn; the total content of unavoidable impurities is ≤0.15%, and the balance is Al; the sum of the mass of Mn and Cr in the aluminum alloy sheet for can lids is 0.40~0.55%.
[0021] In this embodiment of the invention, the aluminum alloy sheet used for can lids has a tensile strength of 430~470MPa, a yield strength of 410~440MPa, and an elongation of 6~8%.
[0022] In this embodiment of the invention, the aluminum alloy sheet for can lid material with a coating for easy-open can lid has a tensile strength of 400~420MPa, a yield strength of 350~370MPa, and an elongation of 7~10%.
[0023] In this embodiment of the invention, the aluminum alloy sheet used for the can lid is 0.200-0.208mm thick, and the 202 series two-piece easy-open can lid made from it has a pressure resistance ≥740KPa, an aging pressure resistance ≥700KPa after forced attenuation by boiling in water at 90℃ for 40min, and an attenuation range ≤30KPa.
[0024] A method for preparing an aluminum alloy sheet for use in can lids with resistance to attenuation includes the following steps: raw materials including aluminum ingots, aluminum can scrap, intermediate alloys and metal additives are batched and then sequentially melted, stirred, first refined, first slag removal, second refined, second slag removal, inert gas refining, settling, casting, ingot heating, hot rolling and cold rolling to obtain the aluminum alloy sheet for can lids.
[0025] In this embodiment of the invention, the refining agent used in the first refining process is HOESCH refining agent LK-961S, with a dosage of 0.05~0.3%, for the first rough refining and to reduce the oxidation and slagging of aluminum and magnesium metals; the refining agent used in the second refining process is HOESCH refining agent LM-60F, with a dosage of 0.05~0.3%, for the second fine refining to remove various suspended inclusions in the aluminum alloy melt. This helps to reduce pinholes and sand holes in the aluminum material and lowers the risk of functional defects such as can lid leakage.
[0026] In this embodiment of the invention, the aluminum can waste is selected from any one or more of 1XXX series aluminum alloys, 3XXX series aluminum alloys and 5XXX series aluminum alloys; the mass percentage of aluminum can waste in the raw materials is 30-75%.
[0027] For the aforementioned types of aluminum can waste, the preparation methods of this application can fully utilize waste aluminum alloy materials, thus reducing production costs. Preferably, controlling the mass percentage of aluminum waste in the raw materials within the aforementioned range helps maintain the stability of the alloy composition. Simultaneously, without compromising material performance, it maximizes the utilization of recycled resources, thereby reducing the amount of new aluminum ingots used, lowering raw material costs, and enhancing product competitiveness.
[0028] In addition, the mass percentage of aluminum can waste in the raw materials can be 70%, 60%, 50%, 40%, 30%, 20% or 10%.
[0029] In this embodiment of the invention, the melting furnace gas temperature is 1100~1150℃, and the metal is melted under full oxygen combustion conditions.
[0030] In this embodiment of the invention, the amount of refining agent used in the first refining is 0.05~0.3%, and the first refining is used to remove the oxide slag of aluminum and magnesium metals in the aluminum alloy melt; the amount of refining agent used in the second refining is 0.05~0.3%, and the second fine refining is used to remove Na, Ca alkali metals and various oxide inclusions in the aluminum alloy melt.
[0031] The first and second refining processes mentioned above are to ensure the cleanliness of the melt under the condition that the waste content is 30-75%, and to reduce pinholes and sand holes.
[0032] In this embodiment of the invention, the casting process includes: using an online degassing and slag removal device to sequentially degas and filter, then adding a grain refiner to perform the casting, thereby obtaining an ingot with a thickness of 560~620mm; wherein the casting temperature is 690~710℃.
[0033] Preferred melting temperatures within the aforementioned range facilitate the complete dissolution of alloying elements in the aluminum can scrap and newly added alloying elements. The preferred casting process not only helps optimize the microstructure, promoting grain refinement and uniform distribution, thereby improving the mechanical properties and formability of the aluminum alloy, but also helps reduce defects such as cracks, porosity, and inclusions, thus improving the integrity and surface quality of the aluminum alloy used for can lids. Preferred grain refiners are Al-5Ti-1B and / or Al-5Ti-0.2C. Controlling the casting temperature within the aforementioned range further promotes grain refinement and reduces the formation of large grains.
[0034] In this embodiment of the invention, the ingot is heated to a temperature of 490~510℃ and held for 3~8 hours.
[0035] Preferably controlling the temperature and time of the homogenization heat treatment within the above range helps to promote partial re-dissolution of AlFeMn without causing over-burning of other low-temperature phases, which is beneficial for thorough crushing in subsequent processing, reducing the generation of large-sized compounds, and thus improving the mechanical and forming properties of aluminum alloys used for can lids.
[0036] In this embodiment of the invention, the initial rolling temperature of the hot rolling is 490~510℃, the final rolling temperature of the hot rolling is 320~340℃, and the thickness of the aluminum alloy after hot rolling is 2.3~3mm.
[0037] Preferably controlling the initial rolling temperature within the above-mentioned range helps to fully utilize the high temperature to promote the re-dissolution of the AlFeMn phase and break it down as much as possible. Preferably controlling the final rolling temperature within the above-mentioned range helps to induce self-annealing in the hot-rolled plate and complete the recrystallization process using the residual heat of hot rolling.
[0038] In this embodiment of the invention, the total processing rate of the cold rolling is 90-94%; the coiling temperature of the finished cold rolling pass is 110-140°C.
[0039] Preferably controlling the total cold rolling rate within the aforementioned range helps refine the grain structure, thereby improving the strength and plasticity of the aluminum alloy used for cans, thus meeting the requirements for can lids. Preferably controlling the coiling temperature of the finished cold rolling pass within the aforementioned range helps balance the strengthening effects of material recovery softening and aging precipitation, thus giving the aluminum alloy material for can lids both high strength and sufficient plasticity, which is beneficial for completing the complex forming process of can lids.
[0040] Specific implementation process: The beneficial effects of this application will be further explained below with reference to the embodiments.
[0041] Example 1 By mass percentage, the elemental composition of the aluminum alloy used for can lids is as follows: 0.107% Si, 0.233% Fe, 0.076% Cu, 0.382% Mn, 4.818% Mg, 0.031% Cr, 0.027% Zn, and 0.016% Ti, with the balance being Al. The sum of the mass of Mn and Cr is 0.413%.
[0042] According to the above composition, aluminum alloy raw materials (aluminum ingots), aluminum can scrap, intermediate alloy, and metal additives are batched and melted at a furnace gas temperature of 1100~1150℃. The aluminum can scrap accounts for 65% of the mass of the aluminum alloy raw materials, and the aluminum scrap consists of 5182 aluminum alloy, 1100 aluminum alloy, and 5083 aluminum alloy. After melting, the mixture is stirred sequentially, and then subjected to a first refining process using 0.05% HOESCH refining agent LK-961S (based on the total amount of molten aluminum), followed by a first slag removal. A second refining process is then performed using 0.1% HOESCH refining agent LM-60F (based on the total amount of molten aluminum), followed by a second slag removal. The mixture is then transferred to a holding furnace for argon refining with permeable bricks, and allowed to stand for 45~60 minutes before casting begins. The casting process utilizes online degassing and slag removal equipment for degassing and filtration, and the addition of grain refiner Al-5Ti-1B. The mixture is then cast into 580mm thick flat ingots using a semi-continuous casting equipment at a casting temperature of 705℃. The flat ingots are heated to a metal temperature of 510℃ and held for 4 hours. They are then rolled, with an initial hot rolling temperature of 500℃. After 1+3 hot continuous rolling, the intermediate slab thickness is 24mm, and the final thickness is 2.7mm. The final rolling temperature is 325~335℃, yielding a hot-rolled coil. The cooled hot-rolled coil is then subjected to initial slab rolling and intermediate cold rolling to a thickness of 0.41mm. Continuous rolling from 0.41mm to 0.29mm to 0.205mm yields the finished aluminum alloy for beverage cans. The coiling temperature for the finished pass is 120~130℃, and the total cold rolling yield is 92.4%.
[0043] Example 2 By mass percentage, the aluminum alloy used for can lids comprises: 0.098% Si, 0.241% Fe, 0.113% Cu, 0.381% Mn, 4.831% Mg, 0.035% Cr, 0.021% Zn, and 0.015% Ti, with the balance being Al. The sum of the mass percentages of Mn and Cr is 0.416%.
[0044] According to the above composition, aluminum alloy raw materials (aluminum ingots), aluminum can scrap, intermediate alloy, and metal additives are batched and melted at a furnace gas temperature of 1100~1150℃. The aluminum can scrap accounts for 65% of the mass of the aluminum alloy raw materials, and the aluminum scrap consists of 5182 aluminum alloy, 1100 aluminum alloy, and 5083 aluminum alloy. After melting, the mixture is stirred sequentially, and then subjected to a first refining process using 0.05% HOESCH refining agent LK-961S (based on the total amount of molten aluminum), followed by a first slag removal. A second refining process is then performed using 0.1% HOESCH refining agent LM-60F (based on the total amount of molten aluminum), followed by a second slag removal. The mixture is then transferred to a holding furnace for argon refining with permeable bricks, and allowed to stand for 45~60 minutes before casting begins. The casting process utilizes online degassing and slag removal equipment for degassing and filtration, and the addition of grain refiner Al-5Ti-1B. The mixture is then cast into 580mm thick flat ingots using a semi-continuous casting equipment at a casting temperature of 705℃. The flat ingots are heated to a metal temperature of 510℃ and held for 4 hours. They are then rolled, with an initial hot rolling temperature of 500℃. After 1+3 hot continuous rolling, the intermediate slab thickness is 24mm, and the final thickness is 2.7mm. The final rolling temperature is 325~335℃, yielding a hot-rolled coil. The cooled hot-rolled coil is then subjected to initial slab rolling and intermediate cold rolling to a thickness of 0.41mm. Continuous rolling from 0.41mm to 0.29mm to 0.205mm yields the finished aluminum alloy for beverage cans. The coiling temperature for the finished pass is 120~130℃, and the total cold rolling yield is 92.4%.
[0045] Example 3 By mass percentage, the aluminum alloy used for can lids comprises: 0.098% Si, 0.241% Fe, 0.113% Cu, 0.412% Mn, 4.831% Mg, 0.051% Cr, 0.021% Zn, and 0.015% Ti, with the balance being Al. The sum of the mass percentages of Mn and Cr is 0.463%.
[0046] According to the above composition, aluminum alloy raw materials (aluminum ingots), aluminum can scrap, intermediate alloy, and metal additives are batched and melted at a furnace gas temperature of 1100~1150℃. The aluminum can scrap accounts for 65% of the mass of the aluminum alloy raw materials, and the aluminum scrap consists of 5182 aluminum alloy, 1100 aluminum alloy, and 5083 aluminum alloy. After melting, the mixture is stirred sequentially, and then subjected to a first refining process using 0.05% HOESCH refining agent LK-961S (based on the total amount of molten aluminum), followed by a first slag removal. A second refining process is then performed using 0.1% HOESCH refining agent LM-60F (based on the total amount of molten aluminum), followed by a second slag removal. The mixture is then transferred to a holding furnace for argon refining with permeable bricks, and allowed to stand for 45~60 minutes before casting begins. The casting process utilizes online degassing and slag removal equipment for degassing and filtration, and the addition of grain refiner Al-5Ti-1B. The mixture is then cast into 580mm thick flat ingots using a semi-continuous casting equipment at a casting temperature of 705℃. The flat ingots are heated to a metal temperature of 510℃ and held for 4 hours. They are then rolled, with an initial hot rolling temperature of 500℃. After 1+3 hot continuous rolling, the intermediate slab thickness is 24mm, and the final thickness is 2.7mm. The final rolling temperature is 325~335℃, yielding a hot-rolled coil. The cooled hot-rolled coil is then subjected to initial slab rolling and intermediate cold rolling to a thickness of 0.41mm. Continuous rolling from 0.41mm to 0.29mm to 0.205mm yields the finished aluminum alloy for beverage cans. The coiling temperature for the finished pass is 120~130℃, and the total cold rolling yield is 92.4%.
[0047] Comparative Example 1 The difference from Example 1 is that, by mass percentage, the aluminum alloy used for the can lid has the following elemental composition: 0.108% Si, 0.247% Fe, 0.078% Cu, 0.571% Mn, 4.831% Mg, 0.093% Cr, 0.024% Zn, and 0.015% Ti, with the balance being Al. The sum of the mass of Mn and Cr is 0.664%.
[0048] Comparative Example 2 The difference from Example 2 is that, by mass percentage, the aluminum alloy used for the can lid has the following elemental composition: 0.107% Si, 0.239% Fe, 0.231% Cu, 0.368% Mn, 4.811% Mg, 0.033% Cr, 0.027% Zn, and 0.015% Ti, with the balance being Al. The sum of the mass percentages of Mn and Cr is 0.401%.
[0049] Comparative Example 3 The difference from Example 2 is that the cold-rolled 0.41mm-0.29mm-0.205mm is not continuously rolled, and the rolling interval is 12 hours. The coiling temperature of the finished pass is 83°C, and the total cold rolling power is 92.4%.
[0050] Comparative Example 4 The difference from Example 1 is that the first refining and the second refining operation are combined into one refining operation, using 0.05% of the total amount of molten aluminum HOESCH refining agent LK-961S and 0.10% of the total amount of molten aluminum HOESCH refining agent LM-60F for refining.
[0051] Test method: Tests for tensile strength, yield strength and elongation of aluminum materials: GBT228.1-2021 "Metallic materials - Tensile testing - Part 1: Test methods at room temperature" Preparation of aluminum alloys for can lids with a coating on the surface of the can lid: Coating the surface of the aluminum alloy for can lid with a PPG resin coating.
[0052] Compressive strength test of can lid material: GB / T 9106.1-2019 "Packaging Containers Two-Piece Cans Part 1: Aluminum Easy-Open Lid Aluminum Cans" specifies the technical requirements, test methods and inspection rules for different types of two-piece cans.
[0053] The test results are shown in Tables 1 and 2.
[0054] Table 1 Table 2 The results above show that Mn and Cr, the strengthening elements in Comparative Example 1, also have a significant effect on improving strength. However, they are prone to producing large-sized coarse compounds such as AlFeMn, CrAl7, and MnAl6 during the casting process, which have an adverse effect on elongation.
[0055] In Comparative Example 2, due to the excessively high content of strengthening Cu, a large number of coarse-sized AlCuMn phases were formed in the aluminum alloy during the casting process, wasting a significant amount of Cu. This not only failed to achieve the solid solution strengthening effect but also led to a reduction in material properties. Furthermore, affected by the coarse compounds, the aluminum alloy material was prone to cracking and stress corrosion cracking during the stamping process.
[0056] In Comparative Example 3, due to insufficient final rolling temperature during cold rolling, the aluminum material lacked the strengthening effects of recovery softening and aging precipitation. Although the initial strength was high, the compressive strength decreased significantly after attenuation aging treatment.
[0057] In Comparative Example 4, after combining the secondary refining in the smelting furnace into a primary refining process, slag was measured using an ABB slag analyzer before casting in the holding furnace. The slag content intercepted by the filter was compared, and the secondary refining scheme was found to be superior. (See Appendix) Figure 1 .
[0058] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: The 5182 can lid material is processed in an H48 state with a cold rolling rate exceeding 90%, resulting in significant work hardening. During coating baking and natural storage, there is a noticeable performance degradation, affecting the can's pressure resistance during service. Therefore, this application optimizes the aluminum alloy composition within the aforementioned range, balancing strength and formability to produce a high-pressure-resistant can lid. This application compares the mechanical properties of aluminum, the pressure resistance and degradation value of the can lid, and formability by adjusting the addition amounts of strengthening elements such as Cu, Mn, and Cr. Furthermore, the aluminum alloy used in this application for the can lid material uses 40-75% scrap aluminum, reducing production costs and resulting in good economic benefits.
[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.
Claims
1. An aluminum alloy sheet for use in ultra-thin can lids with resistance to attenuation, characterized in that: The aluminum alloy sheet used for the can lid comprises the following elements by weight percentage: 0.07~0.15% Si element; 0.15~0.3% Fe element; 0.07~0.15% Cu element; 0.3~0.5% Mn element; 4.75~4.95% Mg; 0.01~0.03% Ti; 0.02~0.10% Cr element; 0.01~0.20% Zn element; the total content of unavoidable impurities is ≤0.15%, and the balance is Al element; the sum of the mass of Mn element and the mass of Cr element in the aluminum alloy sheet used for the can lid material is 0.40~0.55%.
2. The aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 1, characterized in that: The aluminum alloy sheet used for the can lid has a tensile strength of 430~470MPa, a yield strength of 410~440MPa, and an elongation of 6~8%.
3. The aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 1, characterized in that: The aluminum alloy sheet material for can lids with a coating for easy-open can lids has a tensile strength of 400~420MPa, a yield strength of 350~370MPa, and an elongation of 7~10%.
4. The aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 1, characterized in that: The aluminum alloy sheet used for the can lid is 0.200-0.208mm thick. The 202 series two-piece easy-open can lids made from it have a pressure resistance ≥740KPa, and an aging pressure resistance ≥700KPa after forced attenuation by boiling in water at 90℃ for 40min, with an attenuation range ≤30KPa.
5. A method for preparing an aluminum alloy sheet for use in attenuation-resistant ultra-thin can lids as described in any one of claims 1-4, characterized in that, Includes the following steps: The raw materials, including aluminum ingots, aluminum can scraps, intermediate alloys, and metal additives, are sequentially melted, stirred, first refined, first slag removal, second refined, second slag removal, inert gas refining, settling, casting, ingot heating, hot rolling, and cold rolling to obtain the aluminum alloy sheet for the can lid material.
6. The method for preparing the aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 5, characterized in that: The aluminum can scrap is selected from any one or more of 1XXX series aluminum alloys, 3XXX series aluminum alloys, and 5XXX series aluminum alloys; the mass percentage of aluminum can scrap in the raw materials is 30-75%.
7. The method for preparing the aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 5, characterized in that: The melting furnace gas temperature is 1100~1150℃, and the metal is melted under full oxygen combustion conditions.
8. The method for preparing the aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 5, characterized in that: The first refining process uses a refining agent of 0.05-0.3% to remove aluminum and magnesium oxide slag from the aluminum alloy melt. The second refining process uses a refining agent of 0.05-0.3% to remove Na and Ca alkali metals and various oxide inclusions from the aluminum alloy melt.
9. The method for preparing the aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 5, characterized in that: The casting process includes: using an online degassing and slag removal device to sequentially degas and filter, then adding a grain refiner to perform the casting, resulting in an ingot with a thickness of 560~620mm; wherein the casting temperature is 690~710℃.
10. The method for preparing the aluminum alloy sheet for the attenuation-resistant ultra-thin can lid material according to claim 5, characterized in that: The ingot is heated to a temperature of 490~510℃ and held for 3~8 hours; the initial rolling temperature of the hot rolling is 490~510℃, the final rolling temperature of the hot rolling is 320~340℃, and the thickness of the aluminum alloy after hot rolling is 2.3~3mm; the total processing rate of the cold rolling is 90~94%; and the coiling temperature of the finished product pass of the cold rolling is 110~140℃.