JPH05302139A - High strength aluminum alloy sheet excellent in bendability - Google Patents

Abstract

PURPOSE:To provide the objective high strength aluminum alloy sheet excellent in bendability and suitable for a can-top, particularly, for an easy open-end. CONSTITUTION:The aluminum alloy sheet contg., by weight, 3 to 5% Mg, 0.1 to 1.0% Mn, <=0.3% Si, 0.005 5o 0.20% Ti and 0.0005 to 0.04% B and furthermore contg. one or >= two kinds among 0.05 to 0.5% Cu, 0.05 to 0.3% Cr, 0.1 to 0.5% Zn and 0.05 to 0.7% Fe as well as <=1% Fe+Mn, and in which the maximum grain diameter is regulated to <=40mum, the number of intermetallic compounds with >=3mum diameter present within a visual field of 50mum diameter is regulated to <=5 pieces in any place and the number of intermetallic compound grains with >=1mum diameter is regulated to <=4000 pieces/0.2mm<2> is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid material for beer cans, carbonated beverage cans and the like, and more particularly to an easy open end (EOE) material.

[0002]

2. Description of the Related Art At present, as an opening method for beverage cans such as beer cans and carbonated beverage cans, an easy open end (EOE) that can be easily opened by hand without using a device such as a can opener is generally used. ing. As the aluminum alloy used for this easy open end, the conventional 5182 alloy has been mainly used, and the yield strength at that time is about 300 N / mm ² (average tensile strength and yield strength is 335 N / mm ² ).
The manufacturing method of these materials is changing from conventional batch type intermediate annealing to intermediate annealing by a continuous annealing furnace (CAL) in order to increase the strength. However, even when a continuous annealing furnace is used, if the cold rolling ratio is 70% or more, the formability, especially the bendability tends to deteriorate, and the strength is approaching the limit.

[0003]

Therefore, as a countermeasure against the recent trend toward thinner walls, a method has been developed in which not only the strength of the aluminum alloy itself used for the lid material is increased, but also the pressure resistance strength is increased from the aspect of the shape of the lid. Therefore, for example, as a pressure resistant shape, a counter sink having a deeper depth and a corner R of another molding portion made smaller and sharper have been developed. However, such a sharp corner R means that the bending radius becomes small and the molding processing condition becomes severe. Therefore, high bendability excellent in bendability as compared with the material used for the conventional shape,
Materials with high toughness are required. In the case of a material having a low toughness, even if the lid can be molded, fine cracks are generated in the corners and propagate to the coating film to cause a coating film defect, which in turn deteriorates the corrosion resistance. Also, regarding strength, if the material is inferior to the current material, the manufacturer does not adopt it, and a material stronger than the current material is required. The present invention has been made under such circumstances, and an object of the present invention is to provide an aluminum alloy plate for EOE having strength higher than that of conventional materials and excellent in formability, particularly bendability. Is.

[0004]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventor conducted comprehensive research on chemical composition adjustment, structure, manufacturing conditions, etc. so as to obtain properties superior to conventional materials in bending workability and strength. Stacked. As a result, M
It was found that the desired material properties can be obtained by regulating the composition adjustment including g · Mn, the structure, and the manufacturing conditions. That is, the following three points can be mentioned as methods for improving bendability. 1. Reduce the cold rolling rate. 2. Controls intermetallic particles present in the aluminum matrix. Specifically, the number of coarse intermetallic compound particles is reduced and the number of relatively small intermetallic compound particles is reduced. 3. The recrystallized grain size is made fine. In the present invention, with regard to the additive element, the additive amount of Mg is set to 3% or more, and the additive amounts of Mn, Cu, Cr and Zn are adjusted to supplement the strength. In addition, in the metal structure, refining the intermetallic compound particles by increasing the cooling rate during casting,
If necessary, homogenization treatment is performed to enhance the effect of dispersing crystallized substances. Furthermore, they have found that the required strength can be obtained by adjusting the intermediate annealing and cold rolling, and a material excellent in bendability can be obtained.

That is, according to the present invention, Mg: 3% by weight is used.
5%, Mn: 0.1-1.0%, Si: 0.3% or less, and Ti: 0.005-0.
20% alone or B: 0.0005 to 0.04%
Contained together with Cu: 0.05 to 0.5%, C
r: 0.05 to 0.3%, Zn: 0.1 to 0.5%, F
e: One or more of 0.05 to 0.7%, Fe + Mn ≦ 1% or less, the balance being Al and inevitable impurities, and the largest crystal grain in the surface structure of the final plate. Diameter (minor axis perpendicular to rolling direction) ≤40
μm, the number of particles of an intermetallic compound having a diameter of 3 μm or more existing in a visual field of 50 μm in diameter at any location ≦ 5
Number of particles of intermetallic compound having a diameter of 1 μm or more ≦ 4000
It is a high-strength aluminum alloy plate excellent in bendability, which is characterized by the number of pieces / 0.2 mm ² .

[0006]

[Action]

First, the reasons for limiting the chemical components in the present invention will be explained. Mg: Mg is an important element that imparts strength. Without addition of 3% or more, the strength that can be used as EOE cannot be reached, and addition of more than 5% causes deterioration of castability and cold ductility. Is not preferable. Therefore, the amount of Mg is 3-5%
The range is. The addition of Mn: Mn not only has a great effect on the strength improvement but also exerts an effect on the refinement of recrystallized grains. However, Mn
If it is less than 0.1%, its effect is small, and if it exceeds 1.0%, the size of the intermetallic compound is increased and the number thereof is increased, resulting in a decrease in bendability, which is not preferable. Therefore, the Mn content is 0.1 to 1.0%. Ti: Ti is an effective element for stabilizing the structure. If the addition amount is less than 0.005%, the effect is small, and if it is more than 0.2%, a huge compound is formed and bending workability is deteriorated. Therefore, the Ti amount is 0.005 to 0.2.
0% In addition, B may be added in order to enhance the effect, and in that case, 0.0005 to 0.04% is usually added. Cu: Cu addition contributes to strength improvement by age hardening by the intermetallic compound Al-Cu-Mg. But 0.0
If it is less than 5%, its effect is small, and if it is added in excess of 0.5%, the strength becomes too high, resulting in deterioration of moldability. Therefore, the amount of Cu is set to 0.05 to 0.5%. The addition of Zn: Zn is expected to improve the strength by aging precipitation of the intermetallic compound Mg ₂ Zn ₃ Al ₂ , but if it is less than 0.1%, there is no such effect, and if it exceeds 0.5%, there is a problem with the contribution of strength. However, since it deteriorates the corrosion resistance, it is necessary to regulate it below this value. Therefore, the Zn amount is 0.1 to 0.5%. Cr: Cr contributes to the improvement of strength, and if it is less than 0.05%, it has no effect, and if it is added in excess of 0.3%, it causes a decrease in bendability due to the formation of giant crystallized substances. Absent. Therefore, the Cr content is 0.05 to 0.3%. The addition of Fe: Fe forms an intermetallic compound together with Mn during casting to make the recrystallized grain size finer and contribute to the improvement of strength. The effect is not less than 0.05%,
When it is more than 0.7%, the number of intermetallic compounds is increased and bendability is deteriorated, which is not preferable. Therefore, the amount of Fe is set to 0.05 to 0.7%. Since Mn has the same effect as Fe, it is necessary to regulate the total amount of Mn.
Fe + Mn ≦ 1% or less. If the addition of Si: Mg exceeds 3%, the addition of Si becomes M
Strength improvement due to age hardening due to generation of g ₂ Si cannot be expected, and coarse Mg ₂ Si particles are generated, resulting in deterioration of bendability, which is not preferable. However, Si is unavoidable because it mixes in as an impurity. Therefore, the allowable amount of Si is set to 0.3% or less. In the present invention, Mg, Mn and Ti (B)
Is essential, but the element (C
u, Zn, Cr, and Fe) are optional additional elements, and at least one kind is added if necessary.

Next, the reasons for limiting the organization of the present invention will be described. The present invention controls the total amount of Fe + Mn in order to control the dispersion and size of the crystallized compound by Fe and Mn, and further controls the Si amount to reduce the coarse product (Mg ₂ Si) by Si. Is. Specifically, when an intermetallic compound of 3 μm or more segregates microscopically (radius 50 μm), dislocation segregation becomes large due to the final cold rolling, and this portion becomes a starting point of bending cracks. If there are five or more intermetallic compounds having a size of 3 μm or more in this region, this effect becomes significant. Therefore, the number of particles of the intermetallic compound having a diameter of 3 μm or more existing in the visual field of 50 μm in diameter at any location on the surface structure of the final plate is set to 5 or less. Even if there are no particles of coarse intermetallic compounds, 4000 particles / particles of intermetallic compounds of 1 μm or more are present.
The presence of 0.2 mm ² or more reduces the inter-particle distance and acts as if coarse intermetallic compound particles exist, causing segregation of dislocations during cold rolling to become the origin of bending cracks. .. Therefore, the number of particles of the intermetallic compound having a diameter of 1 μm or more is set to 4000 particles / 0.2 mm ² or less at any position on the surface texture of the final plate. When the recrystallized grains become coarse, not only the bendability but also other moldability and the appearance of the molded product due to the surface roughness during drawing and the like are not good, but the recrystallized grains must be coarser than 40 μm. If there is no problem. Therefore, Mn, Fe and Cr are added to refine the crystal grains. Therefore, the structure limitation in the present invention is that the maximum crystal grain size (minor axis in the direction perpendicular to the rolling direction) of the surface structure of the final plate ≦ 40 μm, and the diameter of 3 μm existing in the visual field of 50 μm in diameter at any position.
It is assumed that the number of particles of the intermetallic compound is ≦ 5 and the number of particles of the intermetallic compound having a diameter of 1 μm or more is 4,000 / 0.2 mm ² .

Next, a manufacturing method for obtaining the above-mentioned structure in the aluminum alloy having the above-mentioned component range will be described. The main manufacturing processes are as follows. (1) CC casting → rolling (* 1) → cold rolling → intermediate annealing [CAL (*
2)] → Cold rolling The strength can be improved by solid solution of Mn or the like during casting, and the final cold rolling rate can be reduced. (2) CC casting → rolling (* 1) → CAL annealing (* 3) → cold rolling → intermediate annealing [CAL (* 2)] → cold rolling The structure can be homogenized by performing CAL annealing twice. Further, similarly to (1), the strength can be improved by solid solution of Mn or the like during casting, and the final cold rolling rate can be reduced. (3) CC casting → soaking (* 4) → rolling (* 5) → intermediate annealing [CA
L (* 2)] → Cold rolling Uniformity of the structure and spheroidization / fine dispersion of the crystallized compound are achieved by soaking after casting. Further, strength enhancement due to the solution treatment effect can be achieved by the CAL intermediate annealing. (4) CC casting → rolling (* 6) → soaking (* 4) → rolling (* 5) → intermediate annealing [CAL (* 2)] → cold rolling As in (3), the structure is obtained by soaking after casting. Homogenization and spheroidization / fine dispersion of crystallized compounds, and CAL
The intermediate annealing improves the strength by the solution treatment effect. (5) CC casting → soaking (* 4) → rolling (* 5) → intermediate annealing [batch (* 2)] → cold rolling As in (3), homogenization and crystallization of the structure by soaking after casting. Sphericalization and fine dispersion of the compound can be achieved. Further, by setting the cold rolling ratio to be relatively large, the target strength can be reached even by batch intermediate annealing. (6) CC casting → rolling (* 6) → soaking (* 4) → rolling (* 5) → intermediate annealing [Batch (* 2)] → cold rolling (4) Similar to (4), homogenization of the structure and spheroidization / fine dispersion of the crystallized compound are achieved by soaking after casting.
Further, by setting the cold rolling ratio to be relatively large, the target strength can be reached even in the batch intermediate annealing. Hereinafter, each manufacturing process will be described. : Casting In order to refine intermetallic compound particles crystallized during casting, continuous casting and rolling with a high cooling rate (cooling rate of 50 ° C./s or more (CC or CC casting abbreviated below) is essential for casting. At this time, the cast plate has a plate thickness of 15 mm or less, and if it is thicker than this, a desired crystallized substance size cannot be obtained.
Further, when the plate thickness becomes thinner than 2 mm, the cast structure remains up to the final plate and hinders the formability. * 1: Cold rolling may be used, but by using the residual heat immediately after casting to perform warm or hot rolling together, rolling with a small deformation resistance can be achieved, and energy saving of rolling can be achieved. We can also expect crown control of the rolled plate.
In this case, unless the rolling ratio is 30% or more, uniform and fine crystal grains cannot be obtained by the CAL annealing in the next step. * 2: Intermediate annealing, CAL annealing, heating / cooling rate 1 ° C / s or more, ultimate temperature 400-600
The temperature and the holding time are within 10 minutes to improve the strength by the solution treatment effect. If the ultimate temperature is 400 ° C. or lower, recrystallization does not occur, and if it is 600 ° C. or higher, local eutectic melting occurs, so the temperature is preferably 570 ° C. or lower. The longer the holding time is, the larger the solution treatment effect is, but it is preferably 10 minutes or less in consideration of the deterioration of the appearance due to the formation of an oxide film at a high temperature. In the case of a material that does not go through a soaking process like the above manufacturing processes (1) and (2), the intermediate annealing by CAL that has the effect of refining the crystal grains is essential. Batch annealing Heating / cooling rate 100 ° C / h or less, ultimate temperature 300 to 5
Practically, the holding time at 00 ° C. is preferably about 0.5 to 10 hours. Unless the material is subjected to a soaking process, the recrystallized grain size is coarse and non-uniform. * 3: CAL intermediate annealing The CAL annealing homogenizes the structure and is effective in improving bendability. * 4: The soaking structure is homogenized and the crystallized compound is spherically and finely dispersed, which is effective in improving bendability. Ultimate temperature is 500-5
A holding time of 0.5 h or more is required at 80 ° C. The homogenizing effect is further increased for a long time, but the time may be determined in consideration of the actual manufacturing conditions. If the temperature is 500 ° C. or lower, there is no such effect, and if it is 580 ° C. or higher, eutectic melting may occur. * 5: Rolling after soaking Cold rolling may be used, but by using the residual heat immediately after soaking together with warm or hot rolling, rolling with a small deformation resistance can save energy for rolling. Not only can it be achieved, but the crown control of the rolled plate can also be expected. In this case, unless the rolling ratio is 30% or more, uniform and fine crystal grains cannot be expected in the intermediate annealing in the next step. * 6: Rolling before soaking * Before performing the homogenization treatment of * 4, you may roll to a plate thickness that facilitates soaking. The rolling method at this time is the same as that of * 1. However, the reduction ratio is not specified. : Final cold rolling In any manufacturing process, a final rolling rate of 30% or more is required to obtain the target strength. This final plate is usually used after being subjected to a heating treatment by paint baking, and is subjected to age hardening before the paint baking to increase the strength, or to adjust the strength or stabilize the strength by 100-2.
The final annealing may be performed at 50 ° C. for 30 minutes or more.
In the case of continuously cast and rolled material, an oxide film is present during casting, so electrical / chemical etching with an acid / caustic solution, etc. is performed or mechanically applied from the viewpoint of improving manufacturing stability and product appearance. It is more preferable to remove the oxide film. Also, since the soaking treatment of * 4 above causes remarkable surface oxidation,
The oxygen concentration is preferably 1% or less. It is preferable to remove the surface oxide film even when soaking in a low oxygen concentration atmosphere or soaking in the atmosphere.

[0010]

EXAMPLES Next, examples of the present invention will be described. Table 1 shows the alloy composition of the aluminum alloy used in the examples.

[0011]

[Table 1]

Here, A satisfies the component range described in the claims of the present invention. B is also an alloy of the present invention, but the amount of Mg is reduced with respect to A, and C is used instead.
Strength is obtained by increasing the amounts of r, Cu, and Zn. C is a comparative alloy, and Mg is 2.5%, which is out of the composition range of the present invention and has a small amount of Mg. Further, D is a comparative alloy, and Mn is 0.05%, which is out of the composition range of the present invention and has a small amount of Mn. E is also a comparative alloy,
Contrary to D, the Mn content, the Fe content and the sum thereof are Mn: 0.8.
0%, Fe: 0.35%, Fe + Mn = 1.15%, which exceeds the claimed range. Further, F is also a comparative alloy, and Si: 0.40, which is out of the composition range of the present invention, S
The i amount is excessive.

Next, Table 2 shows the manufacturing method of each embodiment. In the table, "DC" means that the plate was cast to a thickness of 500 mm by the DC casting method, and "CC" means that the thickness was 7 mm when the continuous casting and rolling method was used. Also N
In the o2 warm rolling, the inlet temperature is 250 ° C and the outlet temperature is 200.
No. 4 hot rolling is performed at the inlet side temperature of 400.
C. and the outlet temperature was 300.degree. The intermediate annealing condition is "CAL" because it is CAL and the heating / cooling rate is about 2
0 ° C / s, the temperature reached is the temperature shown in the table, and the temperature was not held. "BAF" means that the heating / cooling rate by the batch annealing furnace was approximately 35 ° C / h, the temperature reached. Is the temperature shown in the table and the holding was carried out under the condition of 2 hours.

[0014]

[Table 2]

Each sample number shown in Table 2 will be described below. No. 1 is a conventional example, and although the alloy components are within the scope of the present invention, the DC of which the manufacturing process has been conventionally performed
Casting is performed by casting, heating, hot rolling, and cold rolling are performed, and intermediate annealing is performed by CAL. No. 2 is an example of the invention corresponding to the manufacturing process (1), and CC casting, warm rolling,
Cold rolling, CAL intermediate annealing, and cold rolling were performed. No3
Is a comparative example for No. 2, in which intermediate annealing was performed in a batch annealing furnace. No. 4 is an invention example corresponding to the manufacturing process (3), in which CC casting is followed by soaking, and intermediate annealing is performed by CAL. No
5 is an invention example corresponding to the manufacturing process (4),
After CC casting, rolling is performed, soaking is performed, and intermediate annealing is performed by CAL. No. 6 is an invention example corresponding to the manufacturing process (5), in which CC casting is followed by soaking, and intermediate annealing is performed in a batch furnace.
No. 7 is an invention example corresponding to the manufacturing process (2), in which CAL annealing was performed twice. No8 is N
Similar to o5, it is an invention example corresponding to the manufacturing process (4), but using alloy B. No. 9 is a comparative example, which uses the alloy C having the same manufacturing process as that of the invention example of No. 4 but having a component composition deviated from the present invention. No
Reference numeral 10 is a comparative example, which is an alloy D having a composition different from that of the present invention with respect to the conventional example of No. 1. N
Reference numeral o11 is a comparative example, which is manufactured by the manufacturing process (3) using the alloy E having a deviated composition. No. 12 is a comparative example, and the alloy F having the same composition as that of No. 11 but having a different composition was used.

The final plate prepared by the above manufacturing method was subjected to an oil bath treatment at 270 ° C. for 20 seconds, which was equivalent to coating baking, and then the strength, formability and microstructure were evaluated. The results are shown in Table 3.

[0017]

[Table 3]

Here, TS is the tensile strength and the unit is N / mm.
² , YS is proof stress in N / mm ² , and El is elongation in%. Flexibility is width 30mm length 40mm
The test piece of 1 is parallel to the rolling direction and has a radius of 0.3 mm.
The test piece after being bent at 80 ° and bent back was subjected to a tensile test and evaluated by its breaking load (N). The metal structure was evaluated based on the crystallized substances and the maximum crystal grains. Of the number of coarse intermetallic compound particles of 3 μm or more in the visual field of radius 50 μm when observing the plate surface as the crystallized substance 1, the largest value, that is, the value of the maximum segregated portion is shown. Also, as crystallized substances 2, the number of fine particles of intermetallic compound having a size of 1 μm or more existing in the visual field of 0.2 mm ² of the plate surface observation (piece / 0.2 m
m ² ). The unit of the maximum crystal grain is μm.

As shown in Table 3 above, under any condition
Even if the invention example is compared with the conventional example and the comparative example, the tensile strength, proof strength, etc.
Has a strength equal to or higher than conventional materials, and
Bendability is far superior to conventional materials. Below, individually
explain about. No. 1 is a conventional example and has a tensile strength of 37.
0 N / mm², Yield strength 300 N / mm²Shows the bendability
Is 900 N. No. 2 is an example of the invention, tensile strength,
The yield strength is almost the same as the conventional example, but the bendability is much improved.
is doing. In addition, the same alloy composition and the same manufacturing professional as No2
The ratio of No. 3 which performed intermediate annealing in a batch annealing furnace
In a comparative example, the size of the largest grain is within the range of the structural requirement of the present invention.
The bendability is worse than that of the conventional example.
No. 4 is an example of the invention, and a coarse crystallized product (crystallized product 1) is fine.
There are few fine crystallized substances (crystallized substance 2), and
The size is also getting smaller. As a result, compared to conventional materials
Both tensile strength and proof strength have been improved, and bendability has been improved.
It has been improved to 3 times that of wood and shows excellent performance.
It No. 5 is an example of the invention, which has twice the bendability of conventional materials.
The tensile strength and proof stress are about 20N /
mm²It's getting stronger. No. 6 is an example of the invention, crystallized product
1 and crystallized substance 2 are slightly large, and the size of crystal grains is also large.
However, the amount is within the scope of the claims of the present invention.
Therefore, it shows sufficiently good performance compared with conventional materials.
It No. 7 is an invention example, and CAL annealing was performed twice.
As a result, the crystal grains are made finer and the bendability is better than that of conventional materials.
It is excellent and has an elongation comparable to that of conventional materials.
It No. 8 is an example of the invention, in which the amount of Mg is reduced and C is used instead.
When the strength is increased by increasing the amount of r, Cu, Zn.
Gold B is used. Bending like No2 and No5
The tensile strength and proof stress are improved as well as the conventional materials.
Is 10 to 20 N / mm ²It's getting stronger. No9 is comparison
It is an example, the same manufacturing process as the invention example of No. 4
An alloy C whose composition is out of the present invention and which has a small amount of Mg was used.
However, the strength is lowered and the bendability is also different from the conventional example.
It's getting worse. No. 10 is a comparative example, and the amount of Mn is
A small amount of alloy D is used, which is a crystallized substance compared to the conventional example.
Although there are few, the crystal grains are coarse and
The size is outside the scope of the present invention, resulting in tensile strength,
The force is almost the same as the conventional material, but the bendability is poor. N
o11 is a comparative example, and the Mn amount, the Fe amount and the sum thereof are
The alloy E, which is out of the scope of the present invention, is used to produce fine crystals.
The amount of the product (crystal product 2) is also outside the scope of the present invention.
Compared to the conventional example, the tensile strength is lower, the elongation is smaller, and the bendability is higher.
Is getting worse. No. 12 is a comparative example, and the amount of Si is
Alloy F which is out of the present invention is used, and coarse crystals
The amount of the product (crystallized product 1) also exceeds the range of the present invention.
As a result, the strength is almost the same as the conventional material, but the bendability is very high.
It's getting worse. As described above, the claims of the present invention
The invention examples satisfying the range of
Etc. has the same strength as the conventional material or 20 N / m than the conventional material
m²It is stronger, and bendability is better than conventional materials.
It is far superior and shows up to 3 times the performance.

[0020]

As described in detail above, according to the present invention, the strength required for EOE materials such as beer cans, carbonated beverage cans, etc. is satisfied, bending workability is excellent, and high strength and thinning tendency are sufficient. It is possible to provide a high-strength aluminum alloy plate that can be used. Moreover, it is not necessary to use a special method as a manufacturing method for satisfying the components and structural requirements of the present invention, and therefore, it is also excellent in manufacturing stability such as stability of performance and cost. By using the aluminum alloy plate excellent in bending workability according to the present invention, even if the demand for a high-strength can lid is increased, the shape of the lid can be devised instead of merely depending on the strength of the material. With this, it became possible to design and devise a lid with high pressure resistance,
Therefore, the degree of freedom in strength design and the like is greatly expanded.

Claims (1)

[Claims] 1. By weight%, Mg: 3-5%, Mn: 0.
1-1.0%, Si: 0.3% or less and microstructure refinement
For stabilization, Ti: 0.005 to 0.20% alone or together with B: 0.0005 to 0.04%,
Further, Cu: 0.05 to 0.5%, Cr: 0.05 to
0.3%, Zn: 0.1-0.5%, Fe: 0.05-
Fe containing one or more of 0.7% and Fe
+ Mn ≦ 1% or less, the balance consisting of Al and unavoidable impurities, and the maximum crystal grain size (minor axis in the direction perpendicular to the rolling direction) ≦ 40 μm of the surface texture of the final plate, diameter at any location Diameter 3 in the field of view of 50 μm
Number of particles of intermetallic compound of μm or more ≦ 5, number of particles of intermetallic compound of diameter 1 μm or more ≦ 4000 / 0.2 mm ²
A high-strength aluminum alloy plate with excellent bendability, which is characterized by