JP3529270B2 - Manufacturing method of aluminum foil - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foil used for foods and other packaging, film capacitors, labels, tobacco, etc., and particularly used for an ultrathin aluminum foil having a foil thickness of 15 μm or less. The present invention relates to a method for manufacturing an aluminum foil having excellent pinhole characteristics.

[0002]

2. Description of the Related Art Conventionally, as aluminum or aluminum alloy for thin foil, pure aluminum such as JIS1N30, 8079 alloy or 8021 alloy has been used as a foil material. In the following, pure aluminum or aluminum alloy is generically referred to as aluminum. Aluminum foil is generally obtained by subjecting these aluminum ingots to homogenization treatment, hot rolling, cold rolling and intermediate annealing, and
After that, it is manufactured by performing cold rolling if necessary.

Then, the aluminum foil obtained is subjected to foil rolling and final annealing to obtain an aluminum foil. By the way, although 5.5 to 7 μm aluminum foil has been put into practical use, most of the foil demand is 6 to 7 μm, and it is desirable to use JIS1N30 for aluminum foil of the same thickness due to compatibility in foil rolling. Is strongly requested. Generally, as a problem associated with the reduction of foil thickness, the number of pinholes is significantly increased, and the barrier property against light, gas, liquid, etc., which the foil originally should have, is deteriorated, and at the time of rolling by pinholes, It is known that foil breaks occur.

It is known that finishing foil rolling of thin foil is usually carried out by polymerization rolling, and pinholes are formed at the maximum waviness of matt surface by connecting with bright surface oil pits. It is also known that pinholes are mainly governed by matte roughness as compared with surface defects such as oil pit surfaces. Furthermore, it is considered that the oil pits are mainly controlled by rolling conditions (reduction / back tension), and the matte surface is formed by free deformation of crystal grains, and it is known that the factor controlled by the foil is large. (Tokuhei 3
-60562, Light Metal Society of Japan 70th Reprint Collection 33,
34, 35).

Therefore, in order to reduce the matte surface roughness,
As a foil capable of suppressing work hardening by decreasing the Fe solid solubility by changing the manufacturing conditions after the Fe content increase and the homogenization treatment and by refining the crystal grains, JP-A-63-2632.
It is disclosed in Japanese Patent Publication No. 2 and the like. Further, it is known to add other elements, for example, as a foil capable of exhibiting the miniaturization of crystal grains and suppression of work hardening by addition of Ni, Mn and Cr, as disclosed in JP-A-63-228228. Japanese Patent Laid-Open No. 63-282244 and Japanese Patent Laid-Open No. 8-3
It is disclosed in Japanese Patent No. 3644 and the like.

[0006]

However, Fe,
The aluminum foil material to which Ni, Mn and Cr are added does not have the above-mentioned merit of compatibility. Also, JIS1N3
With a composition equivalent to 0 (when there is no Fe content), even if the precipitation is promoted by changing the manufacturing conditions after the homogenization treatment, in the foil rolling to obtain an aluminum foil having a foil thickness of 6 to 7 μm, a large work hardening is caused. Not only can you not obtain the suppression effect,
Depending on the process change, the crystal grains may become large on the contrary, which causes problems such as an increase in the amount of pinholes and frequent occurrence of foil breakage during rolling.

The present invention has been made in view of the above problems, and provides a method for producing an aluminum foil, which has a composition equivalent to JIS 1N30 and can be thinned without impairing foil rolling and pinhole characteristics. The purpose is to do.

[0008]

The method for producing an aluminum foil according to the present invention is as follows: Fe: 0.3 to 1.0% by weight, S:
i: Semi-continuous casting of a molten aluminum alloy containing less than 0.15% by weight and the balance being Al and unavoidable impurities at a cooling rate during solidification of 0.3 to 3.0 ° C./sec. After face-shaping, homogenization treatment is performed in the temperature range of 400 to 620 ° C., hot rolling is performed so that the end temperature is in the temperature range of 200 to 260 ° C., and cold rolling is performed after completion of the hot rolling. By subjecting to intermediate annealing at 300 to 450 ° C. for 2 hours or more and further cold rolling, the grain size is reduced to 0.
An aluminum foil having an average interparticle distance of the intermetallic compound of 1 to 0.8 μm of 0.7 to 2.5 μm and an average crystal grain size of 35 μm or less is obtained.
Characterized by foil rolling.

In the present invention, it is preferable that the cold-rolled aluminum foil is foil-rolled in a temperature range of 70 to 110 ° C.

Further, in the present invention, it is preferable that the amount of Cu added to the aluminum alloy is 0.02% by weight or less and the amount of Ti added is 0.03% by weight or less.

Further, in the present invention, by controlling the cooling rate at the time of solidification by casting, the homogenization treatment condition, the cold rolling ratio and the intermediate annealing condition, the interparticle distance is optimized so that the foil rolling property is excellent. After the foil rolling, it is possible to obtain an aluminum foil with few pinholes.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION From the research on aluminum foils and foils up to now, the present inventors have found that reducing pinholes reduces matte surface roughness, that is,
It was found that it is necessary to miniaturize the deformed block when rolling the finishing foil. Furthermore, they have found that the matte surface is formed not only by the crystal grain size but also by free deformation of the dislocation cell size. Further, it is known that suppressing work hardening is effective for reducing pinholes, but it was also clarified that this can be achieved by forming subgrains by dislocation organization.

Therefore, as a result of intensive studies to develop an aluminum foil material exhibiting the above-mentioned characteristics, the interparticle distance of the intermetallic compound having a particle diameter of 0.1 to 0.8 μm was adjusted to the dislocation cell size. It has been found to be effective. Further, in the case of JIS1N30 composition, it is difficult to adjust the inter-particle distance by changing the manufacturing conditions after the conventional homogenization treatment. It has been found that the objective can be achieved by controlling the temperature range of foil rolling while controlling the foil manufacturing conditions in combination. The present invention has been made based on this finding.

That is, in the present invention, Fe: 0.3 to 1.0% by weight, Si: less than 0.15% by weight,
A molten aluminum alloy having a composition in which the balance is Al and inevitable impurities has a cooling rate of 0.3 to 3.0 during solidification.
400 ~ 6 after semi-continuous casting at ℃ / sec and chamfering
The homogenization treatment is performed in the temperature range of 00 ° C and the end temperature is 20
Hot rolling to a temperature range of 0 to 260 ° C., cold rolling after completion of hot rolling, at 300 to 450 ° C.
By performing intermediate annealing for 2 hours or more and further cold rolling, the average interparticle distance of the intermetallic compound having a grain size of 0.1 to 0.8 μm is 0.7 to 2.5 μm, and the average crystal grain is An aluminum foil material having a diameter of 35 μm or less is obtained. The aluminum foil is foil-rolled in the temperature range of 70 to 110 ° C. to obtain an aluminum foil.

The reasons for limiting the components of the aluminum foil in the present invention will be described below.

[0016]Fe: 0.3 to 1.0% by weight Fe has a small solid solubility in aluminum, and
Between Al-Fe-based metals by bonding with other elements in the aluminum
It is an element that forms a compound and also serves as a nucleus for recrystallization.
In order to function, addition of Fe is effective in refining crystal grains.
It When the Fe content is less than 0.3% by weight, during casting
Insufficient number of intermetallic compounds crystallize in the
It is difficult to obtain the effect of miniaturization. On the other hand, the Fe content is 1.0
When the content is more than weight%, an Al-Fe-based intermetallic compound
Since a large number of grains are formed, the grain refining effect is large.
However, the rolling resistance is extremely high because the deformation resistance during foil rolling increases.
Fall to the edge. Therefore, the Fe content is 0.3 to 1.0
Weight%

[0017]Si: less than 0.15% by weight Si is one of the inevitable impurities in the metal. Si
Easily forms a coarse Al-Fe-Si-based intermetallic compound.
Smaller, the number of pinholes increases.
good. Therefore, the Si content is less than 0.15% by weight.
Is desirable.

[0018]Intermetallic compound with a particle size of 0.1 to 0.8 μm
Average particle-to-particle distance: 0.7 to 2.5 μm Intermetallic compounds with a particle size of 0.1 to 0.8 μm are mainly deposited.
It is a good product and is produced by homogenization, hot rolling and intermediate annealing.
To achieve. The distribution of these intermetallic compounds is
In order to affect the accumulation and rearrangement,
Affects the cell-order deformation block size in
You Average interparticle distance of deformed block size intermetallic compounds
If the separation is less than 0.7 μm, the
It becomes a stop, that is, dislocation accumulation becomes excessive, and the polymerization pressure after
Since it becomes a deformed block in units of multiple dislocation cells by extension
Moreover, the matte surface becomes rough and pinholes frequently occur. one
The mean interparticle distance of intermetallic compounds with deformed block size
If the separation exceeds 2.5 μm, it may be
Dislocation simplification becomes easier and it becomes a deformed block in a single cell.
However, the matte surface is rough because coarse cells are easily formed.
And pinholes occur frequently. Therefore, the particle size is 0.1
The average interparticle distance of the intermetallic compound of 0.8 μm is 0.7
To 2.5 μm.

[0019]Average crystal grain size: 35 μm or less The grain size of the foil is the grain size in the intermediate annealing. this
The grain size depends on the deformation block size and
Affects quality strength. Average crystal grain size exceeds 35 μm
In this case, the surface roughness of the mat becomes rough and pin holes are
In addition, the soft strength decreases.

Foil rolling temperature: 70 to 110 ° C. The foil rolling temperature affects the degree of dislocation accumulation and reduction, and therefore affects the dislocation cell order deformation block size in the subsequent polymerizing rolling. When the foil rolling temperature is lower than 70 ° C., the rearrangement of the foil before rising cannot be expressed, and it becomes a deformed block in a plurality of unit cells in the subsequent polymerizing rolling, so that the matte surface becomes rough and the pin There are many holes. On the other hand, when the foil rolling temperature exceeds 110 ° C., dislocation rearrangement becomes too easy, dislocation disappears before one rise, and dislocation accumulation occurs before the next rise. Since it becomes a deformed block in units of a plurality of dislocation cells, the matte surface becomes rough and pinholes frequently occur.

[0021]Cu: 0.02 wt% or less Cu is an element that forms a solid solution in aluminum, and solid solution hardening
Is effective in improving the strength of O material, and if necessary, added
You may add. When the Cu content is less than 0.005% by weight
In this case, solid solution hardening is insufficient and the O material strength is improved.
Hard to get strength. On the other hand, the Cu content is 0.02% by weight.
If it exceeds, the degree of solid solution hardening is too great and the foil is rolled.
Since the deformation resistance of No. 1 increases, the rolling property is extremely reduced.
Therefore, if Cu is 0.02 wt% or less, it is necessary.
You may add according to it.

[0022]Ti: 0.03 wt% or less Ti is added as an Al-Ti or Al-Ti-B mother alloy.
And used for refining the ingot structure. Foil pressure
If streaking becomes a problem after stretching, 0.03% by weight or more
It may be added in the range below, but without adding it
The finer the intermetallic compounds crystallized in the ingot.
Therefore, if there is no hindrance to the streak pattern, less Ti is preferable.
Yes. Therefore, if Ti is 0.03% by weight or less, it is necessary.
You may add according to.

[0023]Inevitable impurities As unavoidable impurities other than the above contained in aluminum
For Mn, Mg, Zn, Cr, V, Zr, Bi, S
n, In, Pb, etc. may be mentioned, but JIS 1100 and J
If the content range is around IS1N30, the purpose of the present invention will be impaired.
It's not like that.

Next, the reasons for limiting the numerical values in the method for producing an aluminum foil according to the present invention will be described.

[0025]Cooling rate during solidification: 0.3 to 3.0 ° C /
sec As mentioned above, it exhibits excellent pinhole characteristics as a foil.
In order to achieve this, a metal with a grain size of 0.1 to 0.8 μm
It is necessary to optimize the average interparticle distance of the interstitial compound. This
The homogenization process that has been performed in the past
It is difficult to make adjustments only by changing the manufacturing conditions thereafter.
Combining the production conditions of the foil material after the optimization and homogenization
Therefore, the purpose is achieved. Immediately
By optimizing the cooling rate during solidification, the distance between particles must be
It will be optimized and will contribute to the reduction of pinholes.

When the cooling rate during solidification exceeds 3.0 ° C./sec, in the ingots slab, the supersaturated solid solution Fe is generated by the subsequent homogenization treatment, hot rolling treatment and intermediate annealing. Emitted as fine precipitates, the number of precipitates of 0.3 μm or less is extremely increased, and the particle size is 0.1 to 0.8 μm.
The average interparticle distance of the intermetallic compound of m becomes narrow, which causes frequent occurrence of pinholes. On the other hand, the cooling rate during solidification is 0 . 3 ° C
If it is less than / sec, floating crystals are generated in the glass screen, and it is difficult to make an ingot as a rolling slab. Therefore, the cooling rate during solidification is 0.3 to 3.0.
C / sec. Preferably, the cooling rate during solidification is 0.3 to 2.4 ° C./sec.

[0027]Homogenization treatment: 400 to 620 ° C After chamfering a slab having the composition and ingot of the present invention,
Apply chemical treatment. This homogenization process controls solid solution and precipitation.
Metals with a particle size of 0.1 to 0.8 μm
It is an important process to optimize the average interparticle distance of intermetallic compounds.
Contributes to the reduction of pinholes. Homogenization temperature is 4
When the temperature is less than 00 ° C, the number of precipitates due to the precipitation of solid solution elements is
Insufficient to increase the distance between particles, pinhole
Cause frequent occurrence. It should be noted that when annealing for a long time, it is homogeneous
The solid solution element is sufficiently precipitated even when the chemical treatment temperature is less than 400 ° C.
However, it is not preferable because the production efficiency is deteriorated. on the other hand,
If the homogenization temperature exceeds 620 ° C, the solid solution element
The number of precipitates due to the precipitation of
Therefore, many pinholes are caused. Therefore, the homogenization process
The processing temperature is 400 to 620 ° C. This homogenization process
The time is not specified, but it should be 2 hours or more.
And are preferred.

[0028]Intermediate annealing: 300 to 450 ° C After the above homogenization treatment, hot rolling and then cold rolling were performed.
Then, intermediate annealing is performed. This annealing is the precipitation of solid solution elements and
The above-mentioned particles are used for the purpose of recrystallization.
The inter-distance is affected by the intermediate annealing temperature. The intermediate annealing temperature is
When the temperature is less than 300 ° C, the number of precipitates due to the precipitation of solid solution elements
Becomes insufficient and the distance between particles is widened.
Invites Le frequently. When performing long-term annealing,
Even if the inter-annealing temperature is less than 300 ° C, solid solution elements are sufficiently precipitated
However, it is not preferable because the production efficiency is deteriorated. on the other hand,
When the intermediate annealing temperature exceeds 450 ° C, the solid solution element
The number of precipitates becomes insufficient due to precipitation, increasing the distance between particles.
Therefore, many pinholes are generated and the average crystal grain size is increased.
Becomes coarse and the strength of O material is insufficient. Therefore, the intermediate annealing temperature
The temperature is 300 to 450 ° C. This intermediate annealing time is special
However, it is preferable to do it for 2 hours or more.
Good

[0029]Finishing hot rolling finish temperature: 200 to 260
℃ To improve the strength of O material and reduce the roughness of matte surface,
Miniaturization is also effective. Finishing hot ends for grain refinement
The hot coil thickness can be increased by lowering the temperature.
It is effective to increase the accumulation of R orientation. Finish
If the upper hot rolling finish temperature is less than 200 ° C,
And the required coil shape cannot be obtained, making it easier to roll in foil rolling.
Inferior. On the other hand, the finish hot rolling finish temperature exceeds 260 ° C.
In this case, the accumulation of R orientation is insufficient, and fine annealing
Crystal grains cannot be obtained. Therefore, if necessary, crystal grains
In the case of miniaturization, the finish hot rolling end temperature is 200 to
You may finish in the range of 260 degreeC.

[0030]

EXAMPLES Examples of the aluminum foil manufactured by the manufacturing method according to the present invention will be specifically described below in comparison with comparative examples.

Example 1 A molten aluminum having the composition shown in Table 1 below was prepared.
DC casting was carried out at the cooling rate during solidification shown in 2 , the slab was faced, homogenized at a temperature of 550 ° C. for 5 hours, immediately followed by hot rolling, and hot rolling at 240 ° C. After that, an aluminum plate having a plate thickness of 5 mm was obtained. After that, cold rolling was performed at a rolling ratio of 86%, and the obtained sheet was subjected to intermediate annealing at a temperature of 375 ° C. for 4 hours. Further, it was cold-rolled to produce an aluminum foil having a thickness of 0.3 mm .

Various evaluations on the obtained aluminum foil
Valuable. First, the foil is rolled at various temperatures and the thickness is 6 μm.
Rollability of aluminum foil produced by
evaluated. As a result, smooth rolling was possible during rolling
○ (good), it is difficult to reduce the wall thickness under the same rolling conditions.
It is difficult or the rolling speed cannot be increased due to insufficient strength.
Causes problems such as difficulty in controlling flatness such as thickness distribution.
When there was a strong tendency to occur, it was rated as x (bad). In addition , those in which the slab could not be removed for rolling due to the generation of floating crystals during the ingot making were also marked as x (defective).

Then, according to a conventional method, a final-annealed aluminum foil having a thickness of 6 μm has a width of 15 mm and an effective length of 1
A test piece formed in a strip shape of 00 mm was manufactured . That
Then, the tensile strength of this test piece was measured by an Instron type tensile tester, and this was taken as the strength of O material. Regarding the strength of the O material, less than 70 MPa is inferior, and one exceeding 70 MPa is excellent.

With respect to the aluminum foil having a thickness of 6 μm, the number of pinholes per 1 m ² (having a diameter of 5 μm or more) was measured by a pinhole detector. 100 or less pinholes / m ² are excellent.

Further, the cooling rate during solidification, the distance between particles and the average crystal grain size were measured by the following methods . The cooling rate at the time of solidification is to collect a steady part on the bottom side of the molten metal by the ingot after ingot formation, then collect a small piece from the position of 100 mm from the skin of the central part of the long side surface, and further after electrolytic polishing, intersect Method and the secondary branch method were used to calculate DAS. Specifically, the method is described in Research Report No. 20 of the Japan Institute of Light Metals, "Dentrite Arm Spacing of Aluminum and Measuring Method of Cooling Rate", and the correction of the measured values of the intersection line method and the secondary branch method is a mathematical formula. The empirical formula shown in 1 was used. The calculation of the cooling rate during solidification, if the Fe content is 0.65 wt% or less using Equation 2, when the Fe content exceeds 0.65 wt% was calculated using Equation 3.

[0036]

## EQU1 ## dr = 1.49 × ds dr: DAS by the intersecting line method, ds: DA by the secondary branch method
S

[0037]

[ ^Formula 2] ds = 33.4 × C ^−0.33 C: Cooling rate during solidification

[0038]

[ ^Formula 3] ds = 77 × C ^−0.42 C: Cooling rate during solidification

The average interparticle distance is such that the particle diameter is 0.1 to 0.
It is the average interparticle distance of the intermetallic compound of 8 μm. The average interparticle distance was measured using a transmission electron microscope and the image processing apparatus. That is, 7.5m from aluminum foil
Take a small piece of m square, grind it to a thickness of 0.1 mm, and
mm had the disconnect out in the shape of a disc. This was subjected to dislocation removal treatment under conditions of a temperature of 350 ° C. and a time of 5 minutes, and was then jet-polished to prepare an observation sample having a thickness of 5 μm. These were observed at a magnification of 10000 times, and the total area was 3
Photographs were taken with a field number of 512 μm ² . Further, at the time of this observation, the observation volume was calculated by measuring the thickness of the observation point by the fringe method. Further, the particle size counted by this observation volume and image processing is 0.1 to 0.
The average interparticle distance was calculated based on the total number of intermetallic compounds of 8 μm.

The average crystal grain size was calculated by the line-of-intersection method from a photograph of a small piece taken from a member subjected to intermediate annealing, which was taken by a polarizing optical microscope at a magnification of 100 times after electrolytic polishing.

Rollability, pinho evaluated by the above method
Number, O material strength, average inter-particle distance and average crystal grain size
It is summarized in Table 2 below.

[0042]

[Table 1]

[0043]

[Table 2]

As shown in Table 2 above, No. 1
Nos. 4 and 6 obtained good rollability. Further, regarding the number of pinholes and the strength of O material, the example No. 1 to 4 and
6 was a preferable value, and a good aluminum foil could be obtained over the whole area.

On the other hand, in Comparative Example No. 20, although the number of pinholes and the O material strength were good, the rolling property was deteriorated due to the addition of excessive Fe. In Comparative Example No. 21, the rolling property was good, but the number of pinholes and the O material strength were inferior to those of the Examples because the crystal grains could not be made fine due to insufficient addition of Fe. Comparative Examples 22 and 24 were good in rollability and O material strength, but Comparative Example No. 22 was added with an excessive amount of Si, and Comparative Example No. 24 was added with an excessive amount of Ti. There has occurred. Comparative example No. 2
In No. 3, although the O material strength was good, the rollability was poor and the amount of pinholes was large due to the addition of excessive Cu.

In Comparative Examples 26, 28, 30 and 32, although the rolling property and the O material strength were good, the cooling rate during the solidification by casting was too fast and the distance between the particles became narrow, so that the matte surface became rough. , An extremely large number of pinholes were generated. In Comparative Examples 25, 27, 29 and 31, the cooling slab could not be manufactured because the cooling rate during solidification by casting was too slow and floating crystals were generated in the glass screen. In Comparative Example No. 33, since the crystal grain size was large, pinholes frequently occurred, and the O material strength was also low. Comparative Example No. 34
Nos. 35 and 35 had many pinholes because the foil rolling temperature was out of the range specified in the claims.

Second Example For ingots having the same composition and cooling rate during solidification as those of Examples No. 1, 4 and 6 shown in Tables 1 and 2 above, after chamfering, under the conditions shown in Table 3 below. subjected to a homogenization treatment, started hot rolled immediately thereafter, exit the hot rolling at a temperature shown in table 3, to obtain an aluminum sheet having a thickness of 5 mm. After that, cold rolling was performed, and intermediate annealing was performed under the conditions shown in Table 3 below.
And cold-rolled in, were fabricated aluminum foil land of thickness 0.3mm. The obtained aluminum foil was foil-rolled at the temperature shown in Table 4 below to produce an aluminum foil having a thickness of 6 μm.

Evaluation was made in the same manner as in the first embodiment described above .
Rollability, number of pinholes, O material strength, average interparticle distance and
The average crystal grain size is summarized in Table 4 below.

[0049]

[Table 3]

[0050]

[Table 4]

As shown in Table 4, Example No.
For Nos. 7 to 12, good rollability was obtained. In addition, regarding the number of pinholes and the strength of O material, the same results as in Example No.
About 12 to 12, it was a preferable value, and a good foil could be obtained over the whole.

On the other hand, Comparative Examples Nos. 36 to 45 were good in rolling property. However, Comparative Example No. 3
In Nos. 6 to 45, the homogenization treatment temperature or the intermediate treatment temperature is out of the range defined in the claims or the rolling ratio is low, the inter-particle distance becomes wide, the matte surface becomes rough, and the pinholes are formed. It happened a lot. Comparative Example No. 39
Nos. 43 and 43 had a high intermediate annealing temperature, and Comparative Example No. 45 had a high hot rolling finish temperature, so that the crystal grains became coarse and the O material strength also decreased. In Comparative Example No. 46, the hot rolling finish temperature is low, so the plane shape required for foil rolling cannot be obtained, and there is a problem in foil rollability. Further, in Comparative Examples Nos. 47 and 48, the foil rolling temperature was out of the range specified in the claims, so that pinholes frequently occurred.

[0053]

As described above in detail, according to the present invention, the interparticle distance is optimized by controlling the cooling rate at the time of solidification by casting, the homogenizing condition, the cold rolling rate and the intermediate annealing condition. It is possible to obtain an aluminum foil which is excellent in foil rollability and has few pinholes after foil rolling.

Further, according to the present invention, by combining the temperature range in hot rolling, the rolling rate per pass, and the optimization of the hot rolling end temperature, the crystal grains can be made finer and the foil after foil rolling can be achieved. With a small number of pinholes,
It is possible to obtain an aluminum foil excellent in O material strength.

Continuation of the front page (56) Reference JP-A-61-257459 (JP, A) JP-A-8-333644 (JP, A) JP-A-6-25781 (JP, A) JP-A-6-293931 (JP , A) JP-A-4-337043 (JP, A) JP-A-59-64754 (JP, A) Miki Isao, Iron index during solidification of Al-Fe alloys, light metal, Japan, Light Metal Society, 1975 January, Vol. 25, No. 1, p. 1-9 (58) Fields surveyed (Int.Cl. ⁷ , DB name) C22F 1/04-1/057 C22C 21/00-21/18

Claims (4)

(57) [Claims] 1. Fe: 0.3 to 1.0% by weight, Si:
A molten aluminum alloy containing less than 0.15% by weight and the balance being Al and unavoidable impurities is semi-continuously cast at a cooling rate during solidification of 0.3 to 3.0 ° C./sec. After shaving, homogenization treatment is performed in the temperature range of 400 to 620 ° C., hot rolling is performed so that the end temperature is in the temperature range of 200 to 260 ° C., cold rolling is performed after completion of the hot rolling, and 300 to By performing intermediate annealing at 450 ° C. for 2 hours or more and further cold rolling, the average interparticle distance of the intermetallic compound having a grain size of 0.1 to 0.8 μm is 0.7.
To 2.5 μm and an average crystal grain size of 35 μm or less is obtained, and the aluminum foil is foil- rolled. 2. The aluminum foil after the cold rolling is
The method for producing an aluminum foil according to claim 1, wherein the foil rolling is performed in a temperature range of 0 to 110 ° C. 3. The method for producing an aluminum foil according to claim 1, wherein the amount of Cu added to the aluminum alloy is 0.02% by weight or less. 4. The method for producing an aluminum foil according to claim 1, wherein the amount of Ti added to the aluminum alloy is 0.03% by weight or less.