JP2686093B2 - Aluminum alloy foil excellent in formability and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aluminum alloy foil used as a material for packaging containers for foods, cosmetics, medicines and the like.

(Prior Art) Since aluminum foil is excellent in blocking moisture, air, and light, it has recently been used by laminating it with a synthetic resin film such as polyethylene for packaging foods, cosmetics, chemicals, etc. Is increasing.

Traditionally, 1N30 has been used for such packaging aluminum foil.
However, due to its low strength and elongation, it is inferior in formability such as bulging and drawing.
Measures were taken such as limiting the shape of the product and increasing the foil thickness.

Therefore, in order to further improve the moldability, 8011 (Fe: 0.6
~ 1.0%), 8079 (Fe: 0.7 ~ 1.3%), and other aluminum alloys with a high Fe content, and 80 with Mn added in addition to Fe.
Aluminum alloys such as 06 (Fe: 1.2 to 2.0%, Mn: 0.3 to 1.0%) are being used. Further, an aluminum alloy foil in which Si is added in addition to Fe and Mn has also been proposed (JP-A-62-62).
-250144).

(Problems to be Solved by the Invention) However, the Fe-containing aluminum alloy has a problem that the formability varies greatly depending on the manufacturing conditions. For example,
On the contrary, when rapid heating is performed in the finish annealing, a phenomenon of coarsening of crystal grains occurs, which may rather deteriorate the formability. Further, variations in strength and formability are likely to occur due to changes in homogenization treatment and intermediate annealing conditions.

In addition, in an aluminum alloy in which Mn, Si, Mg, etc. are added in addition to Fe, these alloy elements are complex compounds with Fe (Al
-Fe-Mn, Al-Fe-Mn-Si, etc.) is generated, and the mechanical properties tend to fluctuate. Further, it is difficult to control the variation in the content of each alloy element, resulting in an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide an aluminum alloy foil of stable quality, which has excellent formability even with a thin foil, and a method for producing the same.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present inventors
On the premise of using an Al-Fe aluminum alloy to eliminate various problems associated with the addition of alloying elements such as n, Si, and Mg, we have conducted diligent research to find a method that can obtain excellent formability without variation. Overlaid.

As a result, by controlling the size and distribution of the intermetallic compound in an appropriate range, the crystal grains of the foil product after finish annealing become fine, and an aluminum alloy foil excellent in formability can be stably obtained. It was a finding.

Further, the inventors have found that such control of the intermetallic compound can be achieved by increasing the working rate of finish cold rolling as much as possible.

That is, the aluminum alloy foil excellent in formability according to the present invention contains 0.7 to 2.0 wt% of Fe, and the balance is 1 μm in the aluminum alloy foil containing Al and unavoidable impurities.
Al-Fe intermetallic compound with a density of more than 5.0 and less than 5.0 μm has a density of 100
It is characterized by being uniformly dispersed at 0 grains / mm ² or more and adjusting the average crystal grain size after final annealing to 30 μm or less.

The method for producing the aluminum alloy foil is characterized by performing finish cold rolling at a cold working ratio of at least 90% or more.

 Hereinafter, the present invention will be described in more detail.

For the aluminum foil of the present invention, an Al-Fe alloy containing 0.7 to 2.0 wt% of Fe and the balance being Al and inevitable impurities is used. When alloy elements other than Fe, such as Mn, Mg, and Si, are contained, the crystal grains tend to become finer, but the mechanical properties tend to fluctuate due to variations in the content of each alloy element. A simple Al-Fe binary alloy is used.

Fe is an essential element for making crystal grains fine, and 0.
If it is less than 7%, this effect is small. On the other hand, if the content exceeds 2.0%, the effect is saturated, and a large intermetallic compound of 5.0 μm or more remains, and due to the notch effect elongation and toughness such as Erichsen. Will rather deteriorate. Therefore, the Fe content is in the range of 0.7 to 2.0%.
It should be noted that impurities can be tolerated as long as the effects of the present invention are not impaired, but it goes without saying that it is preferable that the impurities are as small as possible.

Next, it is necessary to control the size and distribution of the intermetallic compound and the size of the crystal grain within an appropriate range for the following reasons.

Since the intermetallic compound plays the role of the nucleus of the recrystallized grains, it is desirable to disperse as many and evenly as possible in order to make the crystal grains fine. Specifically, at least 10
It is necessary to disperse more than 00 pieces / mm ² . 1000 pieces / mm ²
If the distribution is less than, the effect is insufficient. However, in the case of the above distribution, the intermetallic compound must be more than 1.0 μm and 5.0 μm or less. If it is 1.0 μm or less, the role as a nucleus of crystal grains is small, and a large intermetallic compound exceeding 5.0 μm is not preferable because it rather deteriorates formability as described above.

The average grain size after final annealing (finish annealing) is 30μ.
m. Aluminum foil for molding is often used with a foil thickness of about 40 μm, 30 μm
In the case of crystal grains having a grain size exceeding 1, only 1 to 2 crystal grains can exist in the foil thickness direction, and the deformability deteriorates. Therefore, it is useful to make it as fine as possible, and in order to stably obtain excellent moldability, it should be 30 μm or less, preferably 15 μm.
Do the following.

As described above, the size and distribution of the intermetallic compound are controlled, and Al-Fe having a crystal grain of a predetermined size after the final annealing.
The aluminum foil made of an alloy can be obtained by the same process as the production of a usual aluminum alloy foil, except for finish cold rolling conditions.

That is, in order to obtain the distribution of the intermetallic compound as described above, it is possible to agglomerate the Al-Fe-based crystallized product generated during the agglomeration by applying the highest possible working ratio in the finish cold rolling. is necessary. Further, as the processing rate increases, the generation of dislocations increases, which promotes the generation of recrystallized grains and plays a role of refining the crystal grains. Therefore, in the present invention, the finish cold rolling processing rate is set to exceed 90%.

 Next, examples of the present invention will be described.

(Examples) Al-Fe alloys having various Fe contents shown in Table 1 were melted and ingoted by a conventional method, and hot-rolled sheets having a thickness of 3.5 mm were manufactured by hot rolling.

Next, in order to investigate the effect of the cold rolling ratio, the sheet thickness was changed, intermediate annealing (380 ° C x 2hr) was performed, and the product foil thickness
Cold rolling was performed to 40 μm, and finish annealing was performed at 360 ° C. for 2 hours. The finish cold rolling rate is shown in Table 1.

The size and size of the intermetallic compound were examined by SEM, the crystal grain size was examined by an optical microscope, the tensile strength and elongation were measured by a tensile test, and the moldability was evaluated by an Erichsen test. The results are shown in Table 1.

As is clear from Table 1, the invention examples (No. 3 to No. 6,
No.9) is a commonly used 1N30 product (No.1 to No.2)
It has an elongation of 2 to 3 times that of the above, excellent moldability can be obtained, and the tensile strength can be increased by about 1.5 times. When the Fe content is too high (Comparative Example No. 1
Although 0) has a large number of intermetallic compounds, the elongation is low and the formability is poor. When the finish cold rolling rate is too low (Comparative Examples No. 7 to No. 8), the number of intermetallic compounds is small, the crystal grains become coarse, and the elongation and formability are poor.

(Effects of the Invention) As described in detail above, according to the present invention, the Al-Fe alloy is used as the aluminum alloy foil, the size and distribution of the intermetallic compound are controlled, and the average grain size after final annealing is controlled. Since it is regulated, excellent formability can be obtained even in thin foil, and the strength is sufficient. Therefore, it is possible to reduce the thickness of a conventionally used material and to form a complicated shape that cannot be used conventionally, so that the application can be expanded. Moreover, since it is not necessary to add an alloying element such as Mn or Si as in the conventional aluminum alloy foil, the cost can be reduced, the manufacturing conditions are not easily influenced, and the quality can be stabilized.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C22F 1/00 685 8719-4K C22F 1/00 685Z 694 8719-4K 694A

Claims (2)

(57) [Claims] 1. An aluminum alloy foil containing 0.7 to 2.0% by weight of Fe, the balance being Al and inevitable impurities.
Density of Al-Fe-based intermetallic compound of more than 5.0m but less than 5.0m
An aluminum alloy foil with excellent formability, characterized by being uniformly dispersed at 000 pieces / mm ² or more and having an average crystal grain size after final annealing adjusted to 30 μm or less. 2. A method for producing an aluminum alloy foil having excellent formability, characterized in that, when producing the aluminum alloy foil according to claim 1, finish cold rolling is performed with a cold working rate of at least 90%. .