Aluminum foil blank with low performance deviation and preparation method thereof

Abstract

The invention discloses a low-performance-deviation aluminum foil blank and a preparation method thereof, and belongs to the technical field of aluminum alloy material processing. The aluminum foil disclosed by the invention is prepared from the following components in percentage by mass: 0.6%-0.75% of Fe, 0.45%-0.55% of Si, 0.04%-0.06% of Cu, 0.04%-0.06% of Zn, 0.01%-0.03% of Mn, 0.01%-0.03% of Cr, 0.01%-0.02% of Mg, 0.01%-0.03% of Ti and the balance of Al. The manufacturing method comprises the steps of burdening, smelting, cast rolling, primary cold rolling, homogenizing annealing, rough rolling and finish rolling. The content of Fe and Si in the aluminum foil is optimized, and the aluminum foil which is high in surface quality, good in plate shape, small in performance deviation in the transverse direction, the longitudinal direction and the 45-degree direction and excellent in comprehensive mechanical performance is obtained in combination with the sectional type homogenizing annealing and the hot rolling and cold rolling preparation technology.

Description

Technical Field

[0001] The invention relates to a low-performance deviation aluminum foil blank and a preparation method thereof, and belongs to the technical field of aluminum alloy material processing. Background Art

[0002] Aluminum foil is widely used in medicine and food packaging materials due to its advantages of being non-toxic, tasteless, light-shielding, heat-insulating, moisture-proof, low density and high specific strength. With the development of the pharmaceutical industry and the improvement of product quality, users' quality requirements for pharmaceutical aluminum foil are rapidly increasing. People require higher yield, less pinhole rate, better surface quality and better comprehensive mechanical properties, all of which require the optimization of the aluminum foil processing process.

[0003] Traditional aluminum foil production technology often only allows the billet to recrystallize at high temperature during homogenization annealing, but the grain size of the annealed billet obtained varies greatly, which can easily cause uneven stress distribution and surface quality problems during the subsequent rolling process, resulting in a high pinhole rate in the finished aluminum foil. In addition, since the rolling process uses continuous cold rolling, the plate hardens quickly, the rolling process is difficult and prone to warping, strip breakage and other phenomena. Multiple subsequent finishing rolling is required, which consumes a lot of financial and material resources, and the finished product has large performance deviations in different directions and poor formability. Summary of the invention

[0004] In order to solve the problems existing in the existing aluminum foil and the preparation method thereof, one of the objects of the present invention is to provide a low performance deviation aluminum foil, wherein the chemical composition of the low performance deviation aluminum foil blank comprises, expressed in mass percentage, Fe: 0.6%-0.75%, Si: 0.45%-0.55%, Cu: 0.04%-0.06%, Zn: 0.04%-0.06%, Mn: 0.01%-0.03%, Cr: 0.01%-0.03%, Mg: 0.01%-0.02%, Ti: 0.01%-0.03%, and the balance is Al.

[0005] Another object of the present invention is to provide a method for preparing an aluminum foil blank with low performance deviation, which specifically comprises the following steps:

[0006] (1) The aluminum foil blank is prepared according to its chemical composition and placed in a smelting furnace for heating for rough refining and refining. During the smelting process, a refining agent, hexachloroethane, is added to remove slag and gas to obtain refined aluminum liquid.

[0007] (2) Casting and rolling: The refined aluminum liquid is allowed to stand and filter, and then cast and rolled to obtain cast-rolled billets.

[0008] (3) Initial cold rolling: After the obtained cast-rolled billet is cooled to room temperature, it is subjected to initial cold rolling to obtain a cold-rolled billet.

[0009] (4) Homogenization annealing: The cold-rolled billet is subjected to two-stage homogenization annealing. The conditions of the first stage homogenization annealing are: heating to 320-330°C at a rate of 10°C / min and keeping it at that temperature for 1 hour. The conditions of the second stage homogenization annealing are: slowly heating to 550-560°C at a rate of 5°C / min and keeping it at that temperature for 3 hours, and then cooling to room temperature in air to obtain an annealed billet.

[0010] (5) Rough rolling: The annealed billet is rolled in the order of hot rolling, low-temperature hot rolling, and cold rolling.

[0011] (6) Finishing rolling: The rough rolled billet is placed in a finishing rolling mill and continuously cold rolled for 3 passes to obtain a finished rolled aluminum foil billet.

[0012] Preferably, the heating temperature in step (1) is 750° C.; and the amount of refining agent hexachloroethane added is 0.5% of the total mass of the ingredients.

[0013] Preferably, the casting and rolling conditions in step (2) are as follows: the casting and rolling temperature is 695-700°C, the cooling water inlet temperature of the casting and rolling machine inner cavity does not exceed 25°C, and the water outlet temperature does not exceed 35°C, and at the same time, a grain refiner Al-5Ti-B wire is added, and the added amount is 0.2% of the mass of the aluminum liquid; the thickness of the obtained cast-rolled billet is 7.5 mm.

[0014] Preferably, the thickness of the cold-rolled billet in step (3) is 5.5±0.1 mm.

[0015] Preferably, in the rough rolling process in step (5), the rolling force is 800-1150 KN, and the rolling speed is 10-30 m / min.

[0016] Preferably, in step (5), the hot rolling temperature is 360°C, and the thickness of the billet after hot rolling is 3.3±0.1 mm; the low-temperature hot rolling temperature is 180°C, and the thickness of the billet after low-temperature hot rolling is 1.5±0.1 mm; and the thickness of the billet after cold rolling is 0.4±0.1 mm.

[0017] Preferably, in step (6), the rolling force of the finishing rolling process is 300-490 KN, and the rolling speed is 10-25 m / min.

[0018] Preferably, in step (6), the thickness of the blank obtained by the first cold rolling is 0.29±0.05 mm; the thickness of the blank obtained by the second cold rolling is 0.18±0.05 mm; and the thickness of the blank obtained by the third cold rolling is 0.10±0.05 mm.

[0019] Preferably, during the rolling process in step (5) and step (6), the rolling direction of the previous pass is 90° perpendicular to the rolling direction of the next pass.

[0020] Beneficial Effects of the Invention

[0021] (1) The aluminum foil blank prepared by the present invention has a performance deviation in the transverse, longitudinal and 45° directions of less than 3%, and a cupping value of more than 3 mm.

[0022] (2) The present invention optimizes the content of Fe and Si in the aluminum foil, so that the second phase type in the aluminum foil is mostly β-AlFeSi phase, which not only reduces the hard and brittle phase Al 3 Fe precipitation reduces the plasticity of the material and also improves the overall performance of the material.

[0023] (3) The present invention performs a cold rolling before homogenization annealing to break up the coarse compounds in the cast structure, making them easier to diffuse during subsequent annealing, and also generating more nucleation sites to promote the occurrence of recrystallization.

[0024] (4) The homogenization annealing process is carried out in a graded annealing manner. First, the cold-rolled sheet is slowly heated to 320-330°C. During this process, the Fe, Si and other elements in the supersaturated solid solution are precipitated as much as possible in the form of second phase (β-AlFeSi) particles. After 1 hour of heat preservation, the peak value is reached. The large particles can serve as nucleation sites for recrystallization, and the small particles pin the grain boundaries to prevent abnormal growth of some grains. Then, it is quickly heated to 550-560°C and kept for 3 hours to promote recrystallization and grain growth. The annealed sheet has a uniform grain size. In addition, due to the full precipitation of alloy elements, the distribution of the second phase particles in the aluminum foil matrix is ​​also more uniform.

[0025] (5) The rough rolling after homogenization annealing is carried out by combining hot rolling and cold rolling. Hot rolling can be regarded as normalizing treatment, which softens the plate and reduces the rolling difficulty caused by work hardening. Cold rolling provides the required mechanical properties of the plate. The rolling process is carried out in a way that the rolling direction of the previous pass is perpendicular to the rolling direction of the next pass, which effectively reduces the texture strengthening effect and performance anisotropy caused by unidirectional rolling. In addition, the intermediate annealing step can be omitted, which improves production efficiency and reduces costs. The final aluminum foil billet has high surface quality, good plate shape, small deviation of performance in the transverse, longitudinal and 45° directions, and excellent comprehensive mechanical properties. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below by specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0027] Example 1

[0028] A low performance deviation aluminum foil blank and preparation method thereof

[0029] The mass percentage of the chemical composition of the aluminum foil blank is shown in Table 1:

[0030] Table 1 Chemical composition mass percentage of aluminum foil blank in Example 1

[0031]

[0032] (1) The aluminum foil blank is prepared according to its chemical composition, and the prepared ingredients are placed in a smelting furnace and heated to 750° C. for rough refining and three refinings. During the smelting process, hexachloroethane is added as a refining agent for deslagging and degassing. The amount of hexachloroethane added is 0.5% of the total weight of the prepared ingredients to obtain aluminum liquid.

[0033] (2) Casting and rolling: the aluminum liquid refined in step (1) is allowed to stand and filter, and then enters the casting and rolling mill through a casting nozzle. The casting and rolling temperature is 695° C., the cooling water inlet temperature of the casting and rolling mill is 25° C., and the water outlet temperature is 35° C. At the same time, Al-5Ti-B wire is added as a grain refiner. The addition amount of Al-5Ti-B wire is 0.2% of the mass of the aluminum liquid, and a cast and rolling billet with a thickness of 7.5 mm is obtained.

[0034] (3) Initial cold rolling: The cast-rolled billet obtained in step (2) is cooled to room temperature and then subjected to initial cold rolling. Lubricating oil is applied to the rolls during cold rolling to obtain a cold-rolled billet with a thickness of 5.5±0.1 mm.

[0035] (4) Homogenization annealing: The cold-rolled billet obtained in step (3) is sent to an annealing furnace for a first stage of homogenization annealing, heated to 330°C at a rate of 10°C / min and kept at that temperature for 1 hour, and then a second stage of homogenization annealing is performed, slowly heated to 550°C at a rate of 5°C / min and kept at that temperature for 3 hours, and then cooled to room temperature in air to obtain an annealed billet.

[0036] (5) Rough rolling: The annealed billet obtained in step (4) is continuously rolled on a rough rolling mill in the manner of hot rolling, low-temperature hot rolling and cold rolling. The hot rolling temperature is 360°C and the thickness of the obtained aluminum foil billet is 3.3 mm. The low-temperature hot rolling temperature is 180°C and the thickness of the obtained aluminum foil billet is 1.5 mm. The final thickness of the aluminum foil billet after cold rolling is 0.4 mm. During rolling, the rolling direction of the previous pass is 90° to the rolling direction of the next pass, and lubricating oil needs to be coated on the rollers.

[0037] (6) Finish rolling: The aluminum foil blank obtained in step (5) is placed in a finishing rolling mill and continuously cold rolled for 3 passes. The thickness of the aluminum foil blank obtained by the first cold rolling is 0.29 mm, the thickness of the aluminum foil blank obtained by the second cold rolling is 0.18 mm, and the thickness of the aluminum foil blank obtained by the third cold rolling is 0.10 mm. During the finishing rolling, the rolling direction of the previous pass is 90° to the rolling direction of the next pass, and lubricating oil needs to be applied to the rollers.

[0038] The aluminum foil blank obtained in this embodiment has a performance deviation of 2.68% in the transverse, longitudinal and 45° directions, and a cupping value of 3.46 mm.

[0039] Example 2

[0040] A low performance deviation aluminum foil blank and preparation method thereof

[0041] The mass percentage of the chemical composition of the aluminum foil blank is shown in Table 2:

[0042] Table 2 Chemical composition mass percentage of aluminum foil blank in Example 2

[0043]

[0044] The preparation method of Example 2 is exactly the same as that of Example 1

[0045] The performance deviation of the aluminum foil blank obtained in Example 2 in the transverse, longitudinal and 45° directions is 2.91%, and the cupping value is 3.38 mm.

[0046] Example 3

[0047] A low performance deviation aluminum foil blank and preparation method thereof

[0048] The mass percentage of the chemical composition of the aluminum foil blank is shown in Table 3:

[0049] Table 3 Chemical composition mass percentage of aluminum foil blank in Example 3

[0050]

[0051] The difference between this embodiment and embodiment 1 is that in step (4) homogenization annealing, the first stage annealing temperature is 320° C., and the second stage annealing temperature is 560° C., and the rest of the preparation method is the same as that of embodiment 1.

[0052] The transverse and longitudinal performance deviation of the blank obtained in this embodiment is 2.79%, and the cupping value is 3.57 mm.

[0053] Comparative Example 1

[0054] For comparison, the chemical composition mass percentage of the aluminum foil blank in this comparative example is the same as that in Example 1. The difference between this comparative example 1 and Example 1 is that only one stage of annealing is performed in step (4). The annealing conditions are: slowly heating to 560°C at a rate of 5°C / min and keeping warm for 3 hours. The remaining steps are exactly the same as those in Example 1.

[0055] The aluminum foil blank obtained in this comparative example 1 has a performance deviation of 5.68% in the transverse, longitudinal and 45° directions, and a cupping value of 2.32 mm.

[0056] Comparative Example 2

[0057] As a comparison, the chemical composition mass percentage of the aluminum foil blank in this comparative example is the same as that in Example 1.

[0058] The difference between this comparative example and Example 1 is that the rough rolling in step (5) is not performed, and the specific steps are as follows:

[0059] (1) The aluminum foil blank is prepared according to its chemical composition, and the prepared ingredients are placed in a smelting furnace and heated to 750° C. for rough refining and three refinings. During the smelting process, hexachloroethane is added as a refining agent for deslagging and degassing. The amount of hexachloroethane added is 0.5% of the total weight of the prepared ingredients to obtain aluminum liquid.

[0060] (2) Casting and rolling: the aluminum liquid refined in step (1) is allowed to stand and filter, and then enters the casting and rolling mill through a casting nozzle. The casting and rolling temperature is 695° C., the cooling water inlet temperature of the casting and rolling mill is 25° C., and the water outlet temperature is 35° C. At the same time, Al-5Ti-B wire is added as a grain refiner. The addition amount of Al-5Ti-B wire is 0.2% of the mass of the aluminum liquid, and a cast and rolling billet with a thickness of 7.5 mm is obtained.

[0061] (3) Initial cold rolling: The cast-rolled billet obtained in step (2) is cooled to room temperature and then subjected to initial cold rolling. Lubricating oil is applied to the rolls during cold rolling to obtain a cold-rolled billet with a thickness of 5.5±0.1 mm.

[0062] (4) Homogenization annealing: The cold-rolled billet obtained in step (3) is sent to an annealing furnace for a first stage of homogenization annealing, heated to 330°C at a rate of 10°C / min and kept at that temperature for 1 hour, and then a second stage of homogenization annealing is performed, slowly heated to 550°C at a rate of 5°C / min and kept at that temperature for 3 hours, and then cooled to room temperature in air to obtain an annealed billet.

[0063] (5) Continuous cold rolling: The annealed billet obtained in step (4) is rolled by cold rolling for 8 consecutive times, the thickness of the aluminum foil billet obtained by the first cold rolling is 4.2 mm, the thickness of the aluminum foil billet obtained by the second cold rolling is 3.0 mm, the thickness of the aluminum foil billet obtained by the third cold rolling is 1.9 mm, the thickness of the aluminum foil billet obtained by the fourth cold rolling is 1.0 mm, the thickness of the aluminum foil billet obtained by the fifth cold rolling is 0.6 mm, the thickness of the aluminum foil billet obtained by the sixth cold rolling is 0.35 mm, the thickness of the aluminum foil billet obtained by the seventh cold rolling is 0.20 mm, and the thickness of the aluminum foil billet obtained by the eighth cold rolling is 0.10 mm. During the rolling process, the rolling direction of the previous rolling pass is 90° to the rolling direction of the next rolling pass, and lubricating oil needs to be coated on the rollers.

[0064] The aluminum foil blank obtained in this comparative example has a performance deviation of 3.47% in the transverse, longitudinal and 45° directions, and a cupping value of 2.72 mm.

[0065] Comparative Example 3

[0066] For comparison, the mass percentage of the chemical composition of the aluminum foil blank in this comparative example is the same as that in Example 1. The difference between this comparative example and Example 1 is that in step (5) and step (6), the rolling direction of the previous rolling pass is the same as that of the next rolling pass during the rolling process, and the rest of the preparation method is the same as that in Example 1.

[0067] The aluminum foil blank obtained in this comparative example has a performance deviation of 6.78% in the transverse, longitudinal and 45° directions, and a cupping value of 2.24 mm.

[0068] Comparative Example 4

[0069] In comparison, the difference between this comparative example and Example 1 is that the contents of Fe and Si in the aluminum foil blank are specifically shown in Table 4.

[0070] Table 4 Chemical composition mass percentage of aluminum foil blank in comparative example 4

[0071]

[0072] The preparation method of this comparative example is exactly the same as that of Example 1.

[0073] The aluminum foil blank obtained in this comparative example has a performance deviation of 2.93% in the transverse, longitudinal and 45° directions, and a cupping value of 2.56 mm.

[0074] The aluminum foil blank prepared in Comparative Example 1 has greater performance deviations in the transverse, longitudinal and 45° directions than Example 1, and a smaller cupping value than Example 1. The reason is that the initial annealing adopts a staged annealing method, which can allow the second phase to precipitate as much as possible, and the large particles act as nucleation sites to promote recrystallization, while the small particles pin the grain boundaries to prevent abnormal growth of some grains, thereby ensuring the uniformity of the grain size of the annealed plate and the dispersed distribution of the second phase particles, which is beneficial to improving the processing formability of the plate.

[0075] The aluminum foil blank prepared in Comparative Example 2 has greater performance deviations in the transverse, longitudinal and 45° directions than those in Example 1, a smaller cupping value than that in Example 1, and is rolled more times than in Example 1. The reason is that the hot rolling in the rolling process can be regarded as normalizing treatment, and the plate is processed in a softened state, which can improve the forming properties of the material, reduce the dislocation pile-up phenomenon in the plate, avoid a sharp drop in the plasticity of the material caused by continuous cold rolling, and reduce the number of rolling passes.

[0076] The aluminum foil blank prepared in Comparative Example 3 has greater performance deviations in the transverse, longitudinal and 45° directions than Example 1, and a cupping value is less than Example 1. The reason is that continuous unidirectional rolling will cause the microstructure and mechanical properties of the plate to change in a single direction, and the performance differences in different directions are large. The method of rolling the previous pass at 90° perpendicular to the next pass can reduce the anisotropy of material properties and improve formability.

[0077] The cupping value of the aluminum foil blank prepared in Comparative Example 3 is smaller than that in Example 1. The reason is that when the Fe / Si ratio is large, the excess Fe element will react with the Al matrix to form Al 3 Fe phase is a hard and brittle compound, which is extremely unfavorable to the processing and forming properties of the sheet.

[0078] The above embodiments are only used to help understand the core idea of ​​the low performance deviation aluminum foil blank and the manufacturing method thereof. It should be pointed out that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A low performance deviation aluminum foil blank, characterized by: The chemical composition of the aluminum foil blank, expressed in mass percentage, includes: Fe: 0.6%-0.75%, Si: 0.45%-0.55%, Cu: 0.04%-0.06%, Zn: 0.04%-0.06%, Mn: 0.01%-0.03%, Cr: 0.01%-0.03%, Mg: 0.01%-0.02%, Ti: 0.01%-0.03%, and the balance is Al.

2. The method for preparing the low performance deviation aluminum foil blank according to claim 1, characterized in that: The specific steps include: (1) The aluminum foil blank is prepared according to its chemical composition and placed in a smelting furnace for heating for rough refining and refining. During the smelting process, a refining agent, hexachloroethane, is added to remove slag and gas to obtain refined aluminum liquid; (2) Casting and rolling: After the refined aluminum liquid is allowed to stand and filter, it is cast and rolled to obtain a cast-rolled billet; (3) Initial cold rolling: After the obtained cast-rolled billet is cooled to room temperature, the initial cold rolling is performed to obtain a cold-rolled billet; (4) Homogenization annealing: The cold-rolled billet is subjected to two-stage homogenization annealing. The conditions of the first stage homogenization annealing are: heating to 320-330°C at a speed of 10°C / min and keeping the temperature for 1 hour. The conditions of the second stage homogenization annealing are: slowly heating to 550-560°C at a speed of 5°C / min and keeping the temperature for 3 hours, and then cooling to room temperature in air to obtain an annealed billet. (5) Rough rolling: The annealed billet is continuously rolled in the order of hot rolling, low-temperature hot rolling, and cold rolling; (6) Finishing rolling: The rough rolled billet is placed in a finishing rolling mill and continuously cold rolled for 3 passes to obtain a finished rolled aluminum foil billet.

3. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: In step (1), the heating temperature is 750° C.; the amount of refining agent hexachloroethane added is 0.5% of the total mass of the ingredients.

4. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: The casting and rolling conditions in step (2) are as follows: the casting and rolling temperature is 695-700°C, the cooling water inlet temperature of the casting and rolling machine cavity does not exceed 25°C, and the water outlet temperature does not exceed 35°C. At the same time, a grain refiner Al-5Ti-B wire is added, and the addition amount is 0.2% of the mass of the aluminum liquid; the thickness of the obtained cast and rolled billet is 7.5 mm.

5. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: The thickness of the cold-rolled billet in step (3) is 5.5±0.1 mm.

6. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: In step (5), the rolling force of the rough rolling process is 800-1150 KN, and the rolling speed is 10-30 m / min.

7. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: In step (5), the hot rolling temperature is 360°C, and the thickness of the billet after hot rolling is 3.3±0.1mm; the low-temperature hot rolling temperature is 180°C, and the thickness of the billet after low-temperature hot rolling is 1.5±0.1mm; and the thickness of the billet after cold rolling is 0.4±0.1mm.

8. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: In step (6), the rolling force of the finishing rolling process is 300-490KN, and the rolling speed is 10-25m / min.

9. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: The thickness of the blank obtained by the first cold rolling in step (6) is 0.29±0.05 mm; the thickness of the blank obtained by the second cold rolling is 0.18±0.05 mm; and the thickness of the blank obtained by the third cold rolling is 0.10±0.05 mm.

10. The method for preparing the low performance deviation aluminum foil blank according to claim 2, characterized in that: During the rolling process in step (5) and step (6), the rolling direction of the previous pass is perpendicular to the rolling direction of the next pass by 90°.

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