WO2022185876A1

WO2022185876A1 - Aluminum alloy foil and method for producing same

Info

Publication number: WO2022185876A1
Application number: PCT/JP2022/005350
Authority: WO
Inventors: 俊哉捫垣; 貴史鈴木
Original assignee: Ｍａアルミニウム株式会社
Priority date: 2021-03-05
Filing date: 2022-02-10
Publication date: 2022-09-09
Also published as: JP7334374B2; JPWO2022185876A1

Abstract

This aluminum alloy foil (1) comprises an aluminum alloy having a composition in which 1.2-2.5 mass% of Fe and 0.10 mass% or less of Si are contained and the remaining portion is Al and unavoidable impurities. Regarding the aluminum alloy foil, the stretching in the 0°-direction, the stretching in the 45°-direction, and the stretching in the 90°-direction with respect to the rolling direction are all 20% or more, the average crystal particle size is less than 20 μm, the Cu-orientation density is less than 25, the cube orientation density is 10 or more, and the R-orientation density is 10 or more.

Description

Aluminum alloy foil and its manufacturing method

TECHNICAL FIELD The present invention relates to an aluminum alloy foil and a method for producing the same.
This application claims priority based on Japanese Patent Application No. 2021-035495 filed in Japan on March 5, 2021, the content of which is incorporated herein.

　The aluminum alloy foil used for packaging of food and lithium-ion batteries is required to have high elongation because it is formed with large deformation by press molding. For an aluminum alloy foil with high elongation and good formability, fine and uniform crystal grains and random texture are considered important.

For example, Patent Literature 1 below discloses, as an aluminum alloy foil excellent in formability, an aluminum alloy foil containing Fe and Mg and having a Si content regulated to 0.10% or less.
Further, Patent Document 2 below discloses an aluminum alloy foil containing Fe and Si, limiting the content of Cu and Mn to 0.2% as the upper limit, and limiting the size of crystal grains.

In view of the aforementioned background, the present inventors are conducting research and development on aluminum alloy foils that are suitable as exterior foils for lithium ion batteries.
When the inventor of the present invention examines aluminum alloy foils for packaging materials, the aluminum alloy foils are not necessarily deformed in one direction, but so-called stretch forming is often performed. Therefore, high elongation is required not only in the direction parallel to the rolling direction, which is used as the elongation value of a general material, but also in each direction such as 45° and 90°. Recently, in the field of packaging materials including the field of battery packaging materials, the thickness of packaging materials is becoming thinner.

However, the aluminum alloy foil described in Patent Document 1 does not have sufficient uniformity of elongation in each direction, and there is a problem that it is difficult to uniformly deform the foil by stretch forming or the like.
In addition, in the aluminum alloy foil described in Patent Document 2, a sufficient value for elongation is shown, but in order to refine the crystal grains, Cu and Mn are added with an upper limit of 0.2%. An example is given. Even if these elements are added in a very small amount, the rollability is lowered and the risk of breakage during rolling is increased due to the generation of edge cracks.
In addition, in an aluminum alloy material containing nearly 1.5% Fe, the addition of Mn even in a very small amount causes coarsening of Al-Fe-Mn-based crystallized substances, so if the foil thickness is thin, There is a concern that the risk of breakage during rolling and formation of holes during forming will increase.

JP-A-3-191042 JP 2014-65956 A

The purpose of the present invention is to provide an aluminum alloy foil that has good workability and high formability.

The present inventor conducted a more detailed structural analysis of the aluminum alloy foil for packaging materials, and based on the findings, fundamentally reconsidered the method of manufacturing the alloy, thereby developing a technology capable of providing the desired aluminum alloy foil. The present invention has been reached.
(1) The aluminum alloy foil according to one aspect of the present invention contains Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance is Al and inevitable impurities. It is an aluminum alloy foil made of an aluminum alloy having, with respect to the rolling direction, the elongation in the 0 ° direction, the elongation in the 45 ° direction, and the elongation in the 90 ° direction are all 20% or more, the average crystal grain size is less than 20 μm, Cu It is characterized by an orientation density of less than 25, a Cube orientation density of 10 or more, and an R orientation density of 10 or more.

(2) In the aluminum alloy foil according to one aspect of the present invention, it is preferable that each of the elongation in the 0° direction, the 45° direction, and the 90° direction with respect to the rolling direction is 25% or more.
(3) In the aluminum alloy foil according to one aspect of the present invention, it is preferable that the foil has an average crystal grain size of 8 μm or more and less than 12 μm.

(4) In the aluminum alloy foil according to one aspect of the present invention, it is preferable that the Cu orientation density is 15 or more and less than 25, the Cube orientation density is 10 or more and less than 20, and the R orientation density is 10 or more and less than 15.
(5) A method for producing an aluminum alloy foil according to an aspect of the present invention includes a step of pouring a molten aluminum alloy from a nozzle provided in a tundish into a conveying cooling device, cooling it, and continuously casting a cast plate; A homogenization step of heating the cast plate at 560 ° C. to 620 ° C. for 2 hours or more, a step of cold rolling the cast plate to produce an aluminum alloy foil, and a step of manufacturing the aluminum alloy foil at 220 ° C. to 350 ° C. and a final annealing step of heating for 30 minutes or more at, the aluminum alloy contains Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance is It has a composition that is Al and inevitable impurities, and in the continuous casting process, the cooling rate of the molten metal is set to 50 to 500 ° C./sec, and the process reduces elongation in the direction of 0 ° to the rolling direction, 45 ° An aluminum alloy having an elongation in the direction of 20% or more and an elongation in the 90° direction of 20% or more, an average grain size of less than 20 μm, a Cu orientation density of less than 25, a Cube orientation density of 10 or more, and an R orientation density of 10 or more. A method for producing an aluminum alloy foil, characterized by obtaining a foil.

According to one aspect of the present invention, it is possible to provide an aluminum alloy foil that has good workability and high formability.

1 is a plan view showing a first embodiment of an aluminum alloy foil according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an example of a continuous casting apparatus for manufacturing a cast plate (slab) that serves as a base for the aluminum alloy foil according to the present invention;

An example of an embodiment of the present invention will be described in detail below based on the accompanying drawings. In addition, in the drawings used in the following description, in some cases, characteristic portions are enlarged for convenience in order to make the characteristics easier to understand.

FIG. 1 is a plan view showing one embodiment of an aluminum alloy foil according to the present invention.
The aluminum alloy foil 1 shown in FIG. 1 is a foil obtained by cold-rolling a cast plate obtained by a continuous casting method described later, and the aluminum alloy foil 1 in FIG. 1 has a constant width and a length direction. is depicted as a strip with the
The rolling direction of the aluminum alloy foil 1 is the left-right direction (the length direction of the strip-shaped foil 1) shown in FIG. The direction of 45° to the rolling direction means the direction of the arrow indicated as 45° shown in FIG. 1, and the direction of 90° to the rolling direction means the direction of the arrow indicated as 90° shown in FIG. The direction 90° to the rolling direction in the aluminum alloy foil 1 means, in other words, the width direction of the strip-shaped aluminum alloy foil 1 (vertical direction on the paper surface of FIG. 1).

The aluminum alloy foil 1 shown in FIG. 1 is formed to have a thickness of, for example, approximately 0.1 μm to 0.2 mm. The thickness of the aluminum alloy foil 1 may be a general thickness used as foil.
This aluminum alloy foil 1 is, for example, an aluminum alloy having a composition containing Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance being Al and unavoidable impurities. consists of
Further, the aluminum alloy foil 1 has, for example, an elongation in the direction of 0°, an elongation in the direction of 45°, and an elongation in the direction of 90° with respect to the rolling direction of 20% or more, an average crystal grain size of less than 20 μm, and Cu The orientation density is less than 25, the Cube orientation density is 10 or more, and the R orientation density is 10 or more.

The reasons for limiting the composition, the reasons for limiting the properties, and the reasons for limiting the structure of the aluminum alloy constituting the aluminum alloy foil 1 will be described below.
・Fe: 1.2% by mass or more and 2.5% by mass or less Fe crystallizes as an Al-Fe intermetallic compound during casting, and if the size of these compounds is suitable, it becomes a recrystallization site during annealing. It has the effect of refining the recrystallized grains. If the Fe content is less than 1.2% by mass, the distribution density of the intermetallic compound becomes low, the crystal grain refining effect becomes low, and the final crystal grain distribution becomes uneven. If the Fe content exceeds 2.5% by mass, the effect of grain refinement is saturated or reduced, and the size of the Al—Fe intermetallic compound generated during casting becomes very large, which reduces the elongation of the alloy foil. Also, formability and rollability deteriorate. A particularly preferable Fe content range is 1.2% by mass or more and 1.8% by mass or less.
• Si: 0.10% by mass or less Si forms an intermetallic compound together with Fe, but if added excessively, the size of the compound becomes coarse and the distribution density decreases. If the content exceeds the upper limit, there is a concern that coarse crystallized substances may deteriorate elongation and formability, and furthermore, uniformity of recrystallized grain size distribution after final annealing may deteriorate. For these reasons, the Si content is set to 0.10% by mass or less. For the same reason, it is desirable to set the upper limit of the Si content to 0.04% by mass. Although the lower limit of the Si content is not particularly limited, it is preferably 0.01% by mass or more.

・The elongation in the direction of 0°, the direction of 45°, and the direction of 90° to the rolling direction is 20% or more. be done. Therefore, it is required to have not only elongation in the rolling direction but also good elongation in various directions. If the elongation in any one of the directions described above is less than 20%, the elongation in that direction becomes a constraint, and the formability of the aluminum alloy foil 1 deteriorates.
In order to maintain the formability of the aluminum alloy foil 1, the elongation should be 20% or more in all directions with respect to the rolling direction. In the aluminum alloy foil 1 of the present embodiment, as an example of excellent elongation in all directions, elongation in the direction of 0°, elongation in the direction of 45°, and elongation in the direction of 90° with respect to the rolling direction are intended to be excellent.
More preferably, the aluminum alloy foil 1 has an elongation of 25% or more in the direction of 0°, the direction of 45°, and the direction of 90° with respect to the rolling direction.
Although the upper limit of the elongation in the direction of 0°, the elongation in the direction of 45°, and the elongation in the direction of 90° to the rolling direction is not particularly limited, all of them are preferably 45% or less.

- Average crystal grain size of foil is less than 20 µm The average crystal grain size of the aluminum alloy foil 1 is less than 20 µm, preferably 8 µm or more and less than 20 µm. In the aluminum alloy foil 1 of the present embodiment, it is possible to suppress roughening of the foil surface when deformed by making the crystal grains finer. For this reason, high elongation and accompanying high formability can be expected. If the average crystal grain size of the aluminum alloy foil 1 is 20 μm or more, the crystal grains are coarse, so that the surface of the foil tends to become rough during forming, resulting in deterioration of formability. If the average crystal grain size of the aluminum alloy foil 1 is less than 8 μm, the crystal grains become too fine, the material becomes hard, and there is a concern that the elongation will decrease due to a decrease in the n value.

- The Cu orientation density is less than 25, the Cube orientation density is 10 or more, and the R orientation density is 10 or more. When the Cu orientation density is 25 or more, the Cube orientation density is less than 10, and the R orientation density is less than 10, remarkable anisotropy tends to occur in the elongation of the aluminum alloy foil 1, and the 45° elongation with respect to the rolling direction is improved. On the other hand, both 0° elongation and 90° elongation decrease. Therefore, by setting the Cu orientation density to less than 25, the Cube orientation density to 10 or more, and the R orientation density to 10 or more, the elongation in the above three directions can be balanced, and formability does not deteriorate.
More preferably, the Cu orientation density is 15 or more and less than 25, the Cube orientation density is 10 or more and less than 20, and the R orientation density is 10 or more and less than 15.

"Manufacturing method of aluminum alloy foil"
In order to manufacture the aluminum alloy foil 1 shown in FIG. 1, a molten aluminum alloy M satisfying the composition described above is prepared, and the aluminum alloy cast plate 10 is obtained by continuous casting using this molten aluminum alloy M. Next, the cast aluminum alloy plate 10 is heated at 560° C. to 620° C. for 2 hours or more (homogenization process). Next, the aluminum alloy foil is obtained by cold rolling the aluminum alloy cast plate 10 to a desired thickness. Next, the aluminum alloy foil is heated at 220° C. to 350° C. for 30 minutes or more (final annealing step). As described above, the aluminum alloy foil 1 of the present embodiment can be obtained.

FIG. 2 shows an example of a suitable continuous casting apparatus used when manufacturing the aluminum alloy foil 1. The continuous casting apparatus A shown in FIG. An upper roll (conveying cooling device) 6 and a lower roll (conveying cooling device) 7 are provided. A gutter 8 for replenishing the molten alloy M is provided above the tundish 3 . A supply pipe 9 is provided at the bottom of the gutter 8 so that the molten alloy M can be supplied to the tundish 3 through the supply pipe 9 .

Although the upper roll 6 and the lower roll 7 are illustrated simply in FIG. 2, these rolls have a double structure having a roll core and a roll shell, and a cooling medium (not shown) is provided between the roll core and the roll shell. A flow path is formed so that each roll can be cooled from the inside. In FIG. 2, only a portion of the roll shell is drawn with broken lines, and the details of each roll are omitted.

Since the molten alloy M can be supplied between the upper roll 6 and the lower roll 7 from the tip of the nozzle 5, the upper roll 6 and the lower roll 7 are rotationally driven while supplying the molten alloy M, which is indicated by reference numeral 10 in FIG. Aluminum alloy casting plate can be cast.
The molten alloy is supplied from the tub 8 to the tundish 3 to adjust the amount of the molten alloy in the tundish 3, and the molten aluminum alloy is continuously supplied between the

rolls

6 and 7 from the tundish 3 through the nozzle 5 to produce aluminum. The alloy cast plate 10 can be cast continuously.

An aluminum alloy cast plate 10 can be produced at a cooling rate of about 50 to 500° C./sec by the continuous casting apparatus A shown in FIG. The plate thickness of this cast plate 10 can be about 4 mm to 10 mm, for example, about 7 mm.
By adopting a cooling rate within this range, it becomes easier to obtain a Cu orientation density of less than 25, a Cube orientation density of 10 or more, and an R orientation density of 10 or more in the aluminum alloy foil 1 described later.
The cast aluminum alloy plate 10 thus obtained is subjected to a homogenization treatment. In the homogenization treatment, the cast aluminum alloy plate 10 is heated at 560° C. to 620° C. for 2 hours or more. The heating time is preferably 6 hours to 10 hours. For example, it is heated at 595° C. for 8 hours.

After the aluminum alloy cast plate 10 is produced, cold rolling is performed at a required reduction rate and a required number of times to obtain an aluminum alloy foil having a thickness of about 10 μm to 0.2 mm, for example, a thickness of 40 μm. The working ratio in the final pass of cold rolling is preferably 85 to 95%.
It is preferable to perform cold rolling multiple times and perform intermediate annealing between the cold rolling. In the intermediate annealing, it is preferable to heat to 200° C. to 400° C. for several tens of minutes to several hours. For example, it is preferable to heat to 360° C. for about 3 hours and then slowly cool.
Final annealing is performed after cold rolling. The final annealing conditions are heating at 220° C. to 350° C. for 30 minutes or more. The heating time is preferably 30 minutes to 10 hours. Then, it is desirable to cool slowly.

The aluminum alloy foil 1 with the desired orientation density is obtained by performing the continuous casting process for manufacturing the cast plate at the above cooling rate, the homogenization process, the cold rolling process, and the final annealing process under the above conditions. be able to.
The obtained aluminum alloy foil 1 contains a predetermined amount of Fe, which affects the texture of the aluminum alloy and contributes to the refinement of the crystal grain size. Although it is an aluminum alloy containing Fe in an amount of 1.2 to 2.5% by mass, it has good elongation even with the Fe content in the above range by making it into a cast plate by a continuous casting method. becomes.
In addition to Fe, the aluminum alloy used here may contain Si in an amount of about 0.10% by mass or less. Even if the aluminum alloy foil 1 of the present embodiment contains Si in the above range, an aluminum alloy foil capable of achieving the object can be obtained.

According to the manufacturing method described above, the elongation in the direction of 0°, the elongation in the direction of 45°, and the elongation in the direction of 90° with respect to the rolling direction are all 20% or more, the average grain size is less than 20 μm, and the Cu orientation density is 25 An aluminum alloy foil 1 having a Cube orientation density of 10 or more and an R orientation density of 10 or more can be obtained.
The aluminum alloy foil 1 described above is suitable for food packaging or as a molding packaging material for lithium ion batteries. It is possible to provide an aluminum alloy foil suitable for

The continuous casting apparatus used for manufacturing the aluminum alloy foil 1 according to this embodiment is not limited to the twin roll type shown in FIG. As other continuous casting equipment for continuous casting of aluminum alloys, methods and equipment such as the Hunter method, Lauener Caster I (Alusuisse Caster I), Davey McKee Twin-roll sheet caster, Twin bele caster are also known. You may use either.

A molten aluminum alloy was prepared so as to have the alloy compositions I to X shown in Table 1, and a 7 mm-thick cast was cast at a cooling rate of 50 to 500° C./sec using a twin-roll continuous casting apparatus shown in FIG. An aluminum alloy cast plate was produced. The cast aluminum alloy plate thus obtained was rolled, placed in a heating furnace, and homogenized by heating at 540 to 620° C. for 8 hours.
Next, cold rolling treatment was performed, and intermediate annealing was performed by heating at 200 to 400° C. for 3 hours. As a result, an aluminum alloy foil with a target thickness of 40 μm was obtained. The obtained aluminum alloy foil was subjected to final annealing at 220 to 350° C. for 8 hours to obtain a final product.
Details of the homogenization temperature and time, the intermediate annealing temperature and time, and the final annealing temperature and time within the aforementioned ranges are shown in Table 2 as manufacturing steps A to J.

- Measurement of tensile strength and elongation Both were measured by a tensile test (foil thickness: 40 µm). The tensile test conforms to JIS Z2241, and a JIS No. 5 test piece is taken from each sample so that the elongation in each direction of 0°, 45°, and 90° with respect to the rolling direction can be measured, and a universal tensile tester ( The test was performed at a tensile speed of 2 mm/min with AGS-X (manufactured by Shimadzu Corporation, 10 kN).
Calculation of the elongation rate is as follows. First, two lines are marked at intervals of 50 mm, which is the gauge length, in the vertical direction of the strip-shaped test piece before the test. After the test, measure the distance between the marks by matching the fracture surfaces of the aluminum alloy foil, and subtract the gauge length (50 mm) from it to obtain the elongation amount (mm) divided by the gauge length (50 mm). (%) was obtained.
Regarding the elongation rate, a strip-shaped sample piece for measuring the elongation in the direction of 0° to the rolling direction and a strip-shaped sample for measuring the elongation in the direction of 45° to the rolling direction were used for the obtained aluminum alloy foil. A piece and a strip-shaped sample piece for measuring the elongation in the direction of 90° to the rolling direction were taken and measured.

- Measurement of average grain size The surface of the aluminum alloy foil was electrolytically polished. Then, crystal orientation analysis is performed by SEM (Scanning Electron Microscope)-EBSD, and crystal grain boundaries with an orientation difference of 15 ° or more between crystal grains are defined as HAGBs (high angle grain boundaries), and crystal grains surrounded by HAGBs measured the size of Three visual field sizes of 45×90 μm were measured at a magnification of 1000 times, and the average crystal grain size was calculated. Each crystal grain size was calculated as a circle equivalent diameter, and the EBSD Area method (Average by Area Fraction Method) was used to calculate the average crystal grain size. In addition, OIM Analysis of TSL Solutions was used for the analysis.

Measurement of Crystal Orientation A representative orientation was {112}<111> for the Cu orientation and {123}<634> for the R orientation. {001}<100> was used as a typical Cube orientation.
Each orientation density is obtained by measuring the incomplete pole figures of {111}, {200}, and {220} in the X-ray diffraction method, and using the results, the three-dimensional orientation distribution function (ODF; Orientation Distribution Function) is calculated. and evaluated.

・Maximum forming height The forming height was evaluated by a rectangular cylinder forming test. The test was performed using a universal thin plate forming tester (ERICHSEN model 142/20), and an aluminum foil having a thickness of 40 μm and a shape shown in FIG. It was carried out by molding using a diameter R = 4.5 mm). As the test conditions, the wrinkle suppressing force was 10 kN, the punch rising speed (forming speed) was set to 1, and mineral oil was applied as a lubricant to one side of the aluminum foil (the side to which the punch hits). A punch rising from the bottom of the equipment hits the aluminum foil, and the aluminum foil is molded. It was defined as molding height (mm). The height of the punch was changed at intervals of 0.5 mm. Here, when the overhang height (maximum molding height) was 7.0 mm or more, the moldability was judged to be good, and was described as "B". When the overhang height (limit molding height) was 9.5 mm or more, the moldability was judged to be particularly good (excellent) and was described as "A". When the overhang height (maximum molding height) was less than 7.0 mm, the moldability was judged to be poor and marked as "C".

Either the alloy composition shown in Table 1 or the manufacturing process shown in Table 2 was adopted, and No. Examples 1-27 were made. All of the examples satisfy the desired composition or manufacturing conditions described above.
Either the alloy composition shown in Table 1 or the manufacturing process shown in Table 2 was adopted, and No. Comparative examples 28-37 were made. All of the comparative examples are examples that do not satisfy either the desirable composition or the production conditions described above.
No. 1 to 27 and No. For Comparative Examples 28 to 37, the average grain size, elongation in the 0° direction, elongation in the 45° direction, elongation in the 90° direction, Cu orientation density, Cube orientation density, R orientation density, and limit molding height were measured. , the results of which are set forth in Tables 3-5 below.

As shown in the results shown in Tables 3 and 4, Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance being Al and inevitable impurities. An aluminum alloy foil made of an aluminum alloy and having an average crystal grain size of less than 20 μm, a Cu orientation density of less than 25, a Cube orientation density of 10 or more, and an R orientation density of 10 or more. The elongation in the ° direction, the elongation in the 45° direction, and the elongation in the 90° direction were all 20% or more.
No. specifically shown in Tables 3 and 4. In Examples 1 to 27, the average grain size was in the range of 8.5 to 19.3 μm, and the elongation in the 0° direction, the 45° direction, and the 90° direction were excellent values of 21 to 35%. , and the limit molding height was also 7.0 mm or more. In particular, the limit forming height was 9.5 mm or more in the examples in which the elongation in the direction of 0°, the elongation in the direction of 45°, and the elongation in the direction of 90° to the rolling direction were all 25% or more.

For these examples, No. In Comparative Examples 28 and 29, the casting cooling rate was 5° C./sec or less, the Cu orientation density increased, the Cube orientation density and R orientation density decreased, and the elongation in the 0° direction decreased. Also, No. Comparative Examples Nos. 30 and 31 satisfied the requirements for the alloy composition of the present embodiment, but because the homogenization temperature was low, the crystal grains were as large as 20 μm or more, and the elongation was low. No. Comparative Examples 32 and 33 contained 1.0% by mass of Fe, had an average grain size of more than 20 μm, and had low elongation.
No. Comparative Examples 34 to 36 contained 2.8% by mass of Fe, increased the Cu orientation density, and decreased the elongation in the 0° direction, the 45° direction, and the 90° direction.
No. Comparative Example No. 37 contained more than 0.10% by mass of Si, had an average crystal grain size of 20 μm or more, and had less elongation in the 0° direction. All of these comparative examples had a limit molding height of less than 7.0 mm.

The aluminum alloy foil of this embodiment is suitably applied as a packaging material for foods and lithium ion batteries.

DESCRIPTION OF SYMBOLS 1... Aluminum alloy foil, A... Continuous casting apparatus, 3... Tundish, 5... Nozzle, 6... Upper roll (conveyance cooling means), 7... Lower roll (conveyance cooling means), 8... Gutter, 10... Aluminum alloy casting board.

Claims

An aluminum alloy foil made of an aluminum alloy having a composition containing Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance being Al and inevitable impurities,
The elongation in the direction of 0°, the elongation in the direction of 45°, and the elongation in the direction of 90° with respect to the rolling direction are all 20% or more,
An aluminum alloy foil having an average grain size of less than 20 μm, a Cu orientation density of less than 25, a Cube orientation density of 10 or more, and an R orientation density of 10 or more.
The aluminum alloy foil according to claim 1, wherein the elongation in the direction of 0°, the elongation in the direction of 45°, and the elongation in the direction of 90° with respect to the rolling direction are all 25% or more.
The aluminum alloy foil according to claim 1 or 2, wherein the average grain size is 8 µm or more and less than 20 µm.
The aluminum according to any one of claims 1 to 3, wherein the Cu orientation density is 15 or more and less than 25, the Cube orientation density is 10 or more and less than 20, and the R orientation density is 10 or more and less than 15. alloy foil.
A step of pouring a molten aluminum alloy from a nozzle provided in a tundish into a conveying cooling device and cooling it to continuously cast a cast plate;
A homogenization treatment step of heating the cast plate at 560 ° C. to 620 ° C. for 2 hours or more;
Cold rolling the cast plate to produce an aluminum alloy foil;
a final annealing step of heating the aluminum alloy foil at 220° C. to 350° C. for 30 minutes or longer;
The aluminum alloy has a composition containing Fe: 1.2% by mass or more and 2.5% by mass or less, Si: 0.10% by mass or less, and the balance being Al and inevitable impurities,
In the continuous casting process, the cooling rate of the molten metal is set to 50 to 500 ° C./sec,
By the above process, the elongation in the 0° direction, the elongation in the 45° direction, and the elongation in the 90° direction with respect to the rolling direction are all 20% or more, the average grain size is less than 20 μm, the Cu orientation density is less than 25, and the Cube A method for producing an aluminum alloy foil, comprising obtaining an aluminum alloy foil having an orientation density of 10 or more and an R orientation density of 10 or more.