JPH055149A - Hard aluminum alloy sheet for forming and its production - Google Patents

Abstract

PURPOSE:To provide a hard Al alloy sheet suitable for Al can lid, having high strength, reduced in strength anisotropy, excellent in formability, such as local bulging property and deep drawing ear rate, and contributing toward facilitating the recycle of cans. CONSTITUTION:The sheet is a hard Al alloy sheet which has a composition consisting of 0.5-3.0% Mg, 0.5-2.5% Mn, 0.1-2.5% Fe, and the balance essentially Al and where specific resistivity value, average crystalline grain size, the number of intermetallic compounds of >=6mum, and the number of intermetallic compounds of >=1mum are regulated to >=4.5muOMEGAcm, <=100mum, <=100pieces/0.2mm<2>, and >=2000pieces/0.2mm<2> respectively. Further, besides the above, Cu or Zn can be incorporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength aluminum alloy hard plate for molding, which is mainly used as a material for aluminum cans, and a method for producing the same. More specifically, it has high strength after baking for coating and local protrusion. The present invention relates to an aluminum alloy plate which is excellent in material anisotropy and has excellent recyclability when used as a lid material for a two-piece can, and a method for producing the same.

[0002]

As is well known, a can body of an aluminum two-piece can is assembled by a can body (DI can body) and a can lid (end) by DI processing, and in the case of a normal easy open end, the can body is a can lid. The tab is attached to.

Of these, the body of the can body is required to be excellent in deep drawing property, ironing property, necking workability after DI processing-baking coating, flanging workability, etc. Is an Al-Mn-based 3004 alloy H1
Nine materials and H39 materials are used. With the recent demand for thinner walls, higher strength is required for the body material as well, but even the conventional 3004 alloy can body material has a strength of 270 N / mm ² or more as the yield strength after baking coating. Is obtained.

On the other hand, as a lid material for a can body, a lid material for a can body for beer or other carbonated beverages, that is, a lid material for a can body for use in which the internal pressure is high, is accompanied by a tendency toward thinning in recent years. A high strength of 300 N / mm ² or more is required for the proof stress after painting, and therefore, in general, Al-Mg-based 5182 alloy H1 is used.
8 materials and H38 materials are often used. In addition to these, 5082 alloy and 5052 alloy are also used for the lid material that does not particularly require high strength, and Al-Mn-based 3004 alloy is also used in some cases.

The tab material is not particularly required to have high strength,
With a yield strength of 250 N / mm ² or more and excellent bendability,
5182 alloy, 5082 alloy, 5052 alloy, 3004
Since all the alloys have the above-mentioned strength and have a low workability, there is no particular problem with respect to bendability.

[0006] In addition, deep-drawing cans and DRD cans for food (drawing-redrawing cans) are often made of H52 or H38 of 5052 alloy or H38 of 5042 alloy.

[0007]

In recent years, from the viewpoint of reusing resources and protecting the natural environment, there is an increasing tendency to recover and recycle aluminum cans, that is, recycling. However, when used aluminum cans are collected and redissolved, the ingots (recycled ingots) are obtained by melting the cans and the lids of the cans in a mixed state. Therefore, when the can body and the can lid are composed of alloys of different component compositions, it is necessary to adjust the components in order to produce the desired can body material or can lid material,
Therefore, the cost must be increased.

For example, as described above, the Al-Mn-based 3004 alloy is generally used as the body material of the conventional aluminum two-piece can, and the lid material is used in applications where internal pressure is applied.
Although the 1-Mg-based 5182 alloy is the mainstream, the aluminum can in which the body material made of the 3004 alloy and the lid material made of the 5182 alloy are combined and remelted as described above, and again the body material 3004 alloy or the lid is used. In order to melt the 5182 alloy for material, a new pure aluminum metal, a mother alloy for adding Mg, and other alloy component adjusting materials had to be added to adjust the components.

Therefore, recently, an attempt has been made to form a so-called uni-alloy in which the can body and the can lid are made of an alloy having the same component composition. Formability required for the can body by an alloy having the same component composition, particularly DI processing. In addition to obtaining the necessary ironing property, the moldability required for can lid molding, particularly good local overhanging and deep drawing earrings, and the high strength required for lid materials in applications where internal pressure is applied are obtained. It was extremely difficult. Therefore, in the past, it was actually difficult to achieve uni-alloying.

518 which is conventionally used as a lid material
The two alloys had large strength anisotropy, and therefore had the following problems. That is, in the 5182 alloy rolled plate, the strength differs in the L direction (rolling direction), the C direction (direction orthogonal to the rolling direction), and the 45 ° direction (L direction, 45 ° to the C direction), and generally the L direction. At the maximum and at the minimum in the direction of 45 °, the difference reaches a proof stress value of 20 N / mm ² . If a plate with such a large strength anisotropy is used for the can lid, buckling may occur from the 45 ° direction if pressure is applied after attaching the can body and the can lid. There are problems that sufficient roundness cannot be obtained when pulling out, or sufficient roundness cannot be obtained at the rivet portion when the tab is attached to the lid to form the rivet portion.

Further, as described above, it is desired that the lid member has a particularly excellent local overhanging property among various moldability and a low deep drawing ear ratio.
The 182 alloy was still insufficient in this respect as well.

That is, it is usual that some dimples are formed on the can lid in order to prevent the tabs from rotating and to reinforce, so that the formability (local overhangability) in the local overhang molding for forming the dimples is good. Something is required. Regarding the deep-draw ear ratio, if the outer shape of the can lid is punched, the height is not constant when stacking the can lids after punching, lacking stability, and seaming with the can body. There is a risk that the time will become unfamiliar and the sealing performance of the can will become problematic, and thus a low deep drawing ear rate is required. However, the 5182 alloy cannot be said to be sufficiently excellent in local overhanging property, and the deep drawing ear ratio was still insufficient.

The present invention has been made in view of the above circumstances, and when used as a lid material for an aluminum can, the can is easily recycled, and the strength after baking coating treatment is the conventional high-strength lid material. Was used as 5182
Despite being at least as good as the alloy, it has significantly less strength anisotropy than the 5182 alloy, good local overhanging properties, low deep-drawing earrings, and other formability. The object is to provide an aluminum alloy hard plate.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted diligent experiments and studies to solve the above-mentioned problems, and as a result, the DI
Based on the 3004 alloy that was used as a can body material, the composition of the components was appropriately adjusted, and the solid solution amount of alloy elements such as Mn and Fe, which were expressed using the specific resistance value as an index in the state of the rolled plate, and the crystal By appropriately controlling the grain size and intermetallic compound size, the aluminum alloy hard for molding has high strength after paint baking and little strength anisotropy, good local overhanging property, and low deep drawing ear rate. The inventors have found that a plate can be obtained, and have completed the present invention.

In the process of manufacturing the aluminum alloy hard plate, the solid solution state, the crystal grain size, the intermetallic compound as described above are obtained by increasing the cooling rate during casting and rapidly raising the temperature of the intermediate heat treatment. They have found that a hard plate having a size can be obtained, and have invented a manufacturing method.

Specifically, the aluminum alloy hard plate for molding according to the invention of claim 1 has a Mg content of 0.5-3.0% and a Mn content of 0.5-3.0%.
2.5%, Fe 0.1-2.5%, the balance Al and unavoidable impurities, the specific resistance value at 20 ℃ is 4.5μΩcm or more, and the average grain size in the direction perpendicular to the rolling direction. Is 100 μm or less, the number of intermetallic compounds of 6 μm or more on the plate surface is 100 or less per 0.2 mm ^{2, and the} number of intermetallic compounds of 1 μm or more is 2000 or more per 0.2 mm ^2. To do.

Further, the aluminum alloy hard plate for molding according to the invention of claim 2 has the alloy components defined in the claims,
1 out of 0.05-1.0% Cu and 0.1-1.0% Zn
Containing two or more species, and having a specific resistance value, an average crystal grain size,
The number of intermetallic compounds is defined similarly to the first aspect.

On the other hand, the manufacturing method of the invention of claim 3 relates to the manufacturing method of the aluminum alloy hard plate for forming as defined in claim 1, wherein Mg 0.5 to 3.0%, Mn
An alloy containing 0.5 to 2.5%, Fe 0.1 to 2.5%, and the balance being Al and inevitable impurities is continuously cast at a cooling rate of 50 ° C./sec or more to form a continuously cast plate having a plate thickness of 3 to 15 mm, Then, after subjecting the continuously cast plate to primary cold rolling, the temperature is raised to a temperature in the range of 500 to 620 ° C. at a heating rate of 10 ° C./sec or more and immediately or kept at a temperature in the range for 120 sec or less. After that, the intermediate heat treatment for cooling at a cooling rate of 10 ° C./sec or more and the subsequent secondary cold rolling are performed once or twice or more, and the rolling ratio of the final secondary cold rolling is 30%. As a result, the specific resistance value at 20 ° C. is 4.5 μΩcm or more, the average crystal grain size in the direction perpendicular to the rolling direction is 100 μm or less, and the number of intermetallic compounds of 6 μm or more on the plate surface is Less than 100 per 0.2 mm ^{2 and} 1 The present invention is characterized in that an aluminum alloy hard plate is obtained in which the number of intermetallic compounds of μm or more is 2000 or more per 0.2 mm ² .

The manufacturing method of the invention of claim 4 relates to the manufacturing method of the aluminum alloy hard plate for molding defined in claim 2, and in addition to the constituent elements defined in claim 3, Cu 0.05-1.0%, Zn 0.1-
For alloys containing one or more of 1.0%, the process is almost the same as the process defined in claim 3 (however, the final secondary cold rolling reduction rate is 20% or more).
Is applied.

[0020]

The alloying elements in the aluminum alloy hard plate for forming according to the invention of the present application mainly increase the strength of the aluminum material and suppress softening during baking of the coating,
At the same time, it is added in order to facilitate appropriate control of the crystal grain size and the intermetallic compound size. First, the reasons for limiting the components in the aluminum alloy hard plate for forming of the invention of claim 1 will be explained.

Mg: Mg is a solid solution in an aluminum matrix and is an effective additive element for improving work hardening characteristics. However, in the case of the method of the present invention, since the other components, especially Mn and Fe, are forcibly solid-soluted by increasing the cooling rate during casting, each element synergistically affects work hardening. Since it works, it is not necessary to add as much as 4% as in normal DC casting. Here, the amount of Mg added is
If it is less than 0.5%, the required high strength cannot be obtained after coating and baking, and the recrystallized grains become coarse, impairing the formability, and roughening the skin during forming easily. On the other hand, if the amount of Mg added is
If it exceeds 3.0%, cold rolling property is deteriorated, and ear cracks are liable to occur during cold rolling, yield is lowered, and problems are likely to occur in operation. Therefore, the amount of Mg added is
Within the range of 0.5 to 3.0%.

Mn: Mn is an element which contributes to the improvement of strength and is effective in suppressing the decrease in strength during coating baking. Further, in the lid material mainly used in the present invention, local overhang molding is performed in order to form the dimple portion. If a shear band called a Luder's mark is generated at such a local overhang forming portion, it causes cracking. Therefore, the generation of such a Luder's mark must be suppressed. Crystallization of fine intermetallic compounds is effective in suppressing the Luder's mark and, in turn, improving the local overhanging property, and is also effective in reducing the anisotropy of strength. However, the amount of Mn added is 0.5%
If it is less than 2.5%, this effect cannot be obtained. On the other hand, if it exceeds 2.5%, the cold rolling property is extremely deteriorated and the castability is extremely deteriorated. Therefore, the addition amount of Mn is set to the range of 0.5 to 2.5%.

Fe: Fe is an element which is extremely effective for forcibly forming a solid solution similarly to Mn to improve work hardening and resistance to baking and softening, and to obtain high strength after baking for coating. It should be noted that addition of Fe significantly reduces the solid solution amount of Mn, but since the reduction of the solid solution amount of Mn means that fine precipitates are generated, conversely, work hardening and bake softening suppression are also performed. It is valid. If the added amount of Fe is less than 0.1%, the effect cannot be obtained. On the other hand, if the added amount of Fe exceeds 2.5%,
The precipitates may become coarse and rather soften during coating baking. Therefore, the amount of Fe added is 0.1 to 2.5.
Within the range of%.

As described above, in the aluminum alloy hard plate for forming according to the invention of claim 1, M is used as an essential alloy component.
Addition of g, Mn, and Fe, work hardening by solid solution of Mg, work hardening by forced solid solution of transition elements Mn, Fe, and suppression of softening during baking of paint, and further generation of Luders mark during molding Are taken into consideration, such as the suppression of cold rolling, reduction of strength anisotropy, and cold rolling property.

Further, in the aluminum alloy hard plate for molding according to the invention of claim 2, in addition to the above-mentioned Mg, Mn, Fe, C
By adding u and / or Zn, in addition to the above-described effects of Mg, Mn, and Fe, the strength after coating baking is further improved by age hardening during coating baking treatment. Next, the reasons for limiting the addition amounts of Cu and Zn in the aluminum alloy hard plate for molding according to the second aspect of the present invention will be described.

Cu: Cu is effective for age hardening during coating baking as described above, and thereby for improving the strength of the plate after coating baking. This effect is
It occurs during the precipitation process of Cu-Mg based precipitates. To obtain this effect, it is necessary to add at least 0.05% Cu. On the other hand, when Cu is added in an amount of 1.0% or more, age hardening is easily obtained, but work hardening easily occurs during cold rolling, and workability is impaired. Therefore, when Cu is added, the addition amount of Cu is set within the range of 0.05 to 1.0%.

It is well known that Zn: Zn can also be expected to age harden due to the interaction with Mg and Cu. In the present invention as well, the addition of Zn is the strength of the plate after coating baking due to age hardening during coating baking treatment. We are trying to improve. If Zn is less than 0.1%, the effect cannot be obtained.
If Zn is added in an amount of more than 1.0%, the strength is improved, but the work-hardening property is strengthened, and the draw formability and redraw formability are extremely impaired. Therefore, the amount of Zn added when Zn is added is within the range of 0.1 to 1.0%.

Basically, the balance of each of the above components may be Al and inevitable impurities in any of the inventions of the present application, but Cr, Zr, and V contribute to the improvement of strength, and all 0.3 %, The effects of the present invention will not be impaired, so about 0.3% is allowed for each.

In a normal aluminum alloy,
A small amount of Ti or Ti and B may be added for refining the crystal grains of the ingot. Even in the aluminum alloy hard plate for molding of the present invention, a small amount of Ti or T may be added.
i and B may be contained. However, when Ti is added, if the addition amount is less than 0.01%, the effect of Ti addition cannot be obtained, and if it exceeds 0.50%, TiAl ₃ crystallizes and impairs formability, so Ti is 0.01 to 0.50%. It is preferable to set it within the range. When B is added together with Ti, if the amount of B added is less than 1 ppm, the effect of B addition is not
On the other hand, if it exceeds 1000 ppm, coarse particles of TiB ₂ are mixed and impair the formability. Therefore, it is preferable that B is in the range of 1 to 1000 ppm.

Further, in the aluminum alloy hard plate for forming of the present invention, in addition to containing the above alloy elements, the specific resistance value measured at 20 ° C. (room temperature) in the state of the final rolled plate is 4.5 μΩcm or more. And the average grain size in the direction perpendicular to the rolling direction is 100 μm or less as the crystal grain size condition, and the intermetallic compound of 6 μm or more on the plate surface as the intermetallic compound crystallized product size condition. The number of crystallized substances is 0.2 or less per 0.2 mm ² , and the number of crystallized intermetallic compounds of 1 μm or more is 0.2.
It is necessary that the number is 2000 or more per mm ² .

Although the specific resistance value of a metal material corresponds to the solid solution amount, in each invention of the present application, solid solution elements, mainly Mn,
In order to effectively function the bake softening resistance and age hardening due to the solid solution of Fe, the specific resistance value (at 20 ° C.), which is an index of the solid solution amount, needs to be 4.5 μΩcm or more. Two
If the specific resistance value at 0 ° C. is less than 4.5 μΩcm, sufficient strength cannot be obtained after baking.

Further, a relatively large intermetallic compound having a diameter of 6 μm or more is likely to be a starting point of cracking during local stretch forming, and in order to improve local stretch formability, an intermetallic compound having a diameter of 6 μm or more is 0.2 mm. ^It is necessary to limit the number to 100 or less per ² . On the other hand, if a large number of relatively fine intermetallic compounds smaller than 6 μm are present, the strength anisotropy can be reduced, and at the same time, the occurrence of shear bands in the local stretch forming can be prevented and the local stretch forming property can be improved. It also contributes to the improvement of strength. However, it is actually possible to count correctly the intermetallic compounds of 1 μm or more. Therefore, the number of intermetallic compounds of 1 μm or more is 0.2 mm ²
It is defined as more than 2000 pieces. The number of these intermetallic compounds may be investigated using an image analyzer.

Regarding the crystal grain size, if coarse crystal grains of 100 μm or more are present, not only the moldability is generally deteriorated, but also rough skin is generated during molding, resulting in poor appearance. Then, the average crystal grain size was defined as 100 μm or less. Since the crystal grains in the rolled plate are elongated in the rolling direction, the above grain size regulation of 100 μm or less means the grain size in the direction perpendicular to the rolling direction.

Next, a method for producing the above-described aluminum alloy hard plate for forming, that is, the methods of the inventions of claims 3 and 4 will be described.

First, a melt of an alloy having the above-described composition is melted according to a conventional method, and continuously cast into a plate having a thickness of 3 to 15 mm by a continuous casting method such as a thin plate continuous casting method (continuous casting and rolling method). Then, wind it into a coil. The cooling rate during this continuous casting needs to be a high cooling rate of 50 ° C./sec or more. Originally, the transition metals Mn and Fe are difficult to form a solid solution with aluminum, and most of them crystallize when the cooling rate during casting is low. To achieve the effect, 50
A cooling rate of ℃ / sec or more is required. If the cooling rate during casting is less than 50 ° C./sec, the amount of solid solution is insufficient, and it is not possible to sufficiently improve the strength of the plate after baking. Note that Fe crystallizes or precipitates to some extent even at a cooling rate of 50 ° C./sec or more. However, within the component composition range of the present invention, crystallized substances and precipitates become extremely fine at a high speed of 50 ° C./sec or more,
This is advantageous in terms of improving strength, suppressing Ludersmarks, and reducing strength anisotropy.

The continuous cast plate obtained as described above is
Subsequently, cold rolling is performed by sandwiching one or more intermediate heat treatments (intermediate annealing). That is, after the intermediate plate thickness is obtained by the primary cold rolling, the intermediate heat treatment is performed, and then the final cold rolling is performed by the secondary cold rolling to finish the product sheet thickness, or after the primary cold rolling, The intermediate heat treatment and the secondary cold rolling are repeated, and the final secondary cold rolling is performed to finish the product sheet thickness.

In the intermediate heat treatment in the above process, the aging effect by the solid solution Cu, Zn, Mg and the transition metals Fe, M
It is intended to improve the rolling property without impairing the effect of the bake softening resistance due to n, and also to improve the deep drawing earring ratio and other formability. In this intermediate heat treatment, both the heating rate and the cooling rate were 10 ° C / ° C so that precipitation did not occur during heating (during temperature increase) and during cooling.
sec or more is required, and the ultimate temperature of 500 ° C or more is required to obtain a completely recrystallized uniform structure, but if it exceeds 620 ° C, eutectic melting occurs and the plate is cut during operation. There is a danger of causing
It was within the range of 20 ° C. It is preferable to keep the temperature within the range of 500 to 620 ° C. as short as possible because precipitation is less, but 120 seconds or less is acceptable. Such an intermediate heat treatment of rapid heating of 10 ° C./sec or more, rapid cooling and no holding or short-time holding of 120 sec or less can be achieved by using a continuous annealing furnace. Further, by applying such continuous annealing of rapid heating and rapid cooling, recrystallized grains are made finer, which contributes to improvement of formability.

The composition ratio of the invention according to claim 1, wherein the rolling ratio in the final cold rolling (final secondary cold rolling for finishing the product sheet thickness) does not substantially contain Cu and / or Zn. The alloy according to claim 2 contains Cu and / or Zn in an amount of 30% or more.
It should be 0% or more. If the final cold rolling ratio is less than the above range, the required strength after baking the coating cannot be obtained. On the other hand, the rolling ratio in the final cold rolling is preferably as small as possible in order to reduce the deep drawing earring ratio, and therefore is usually 90% or less. 90 both when substantially free of Cu and / or Zn and when containing Cu and / or Zn
A rolling ratio of less than or equal to 10% can obtain a sufficiently higher strength after coating baking than that of the conventional material, and a rolling ratio of less than or equal to 90% can provide a deep drawing earring with practically no problem.

The number of intermediate heat treatments may be set to the minimum number in consideration of rollability, but it is preferable to perform the intermediate heat treatment at least twice from the viewpoint of ear ratio. It is possible to obtain a so-called non-ear material that has no

The rolled plate having the final plate thickness obtained by the final cold rolling may be directly used for a can lid or the like, but at a temperature in the range of 100 to 200 ° C. for about 30 minutes to 10 hours. The final annealing may be performed, and in this case, the reduction in strength due to the coating baking treatment can be further reduced.

The aluminum alloy hard plate for molding obtained through the above steps has a strength after coating baking which is a necessary condition as a material mainly used for a can lid for an easy-open can. It is superior to a JIS 5182 alloy H38 material, has less strength anisotropy, has a low deep-drawing earring rate, and has excellent local overhanging properties. It is a molding material that can make the can lid thinner and lighter than before. .. In addition, 300 which is conventionally used as a can body
Since it has a composition close to that of the 4-alloy, it can be used as a can lid for a two-piece can by making the composition close to that of the body of the can or the same composition as the body of the can. Can be easily recycled.

When the aluminum alloy hard plate for forming as described above is used for a can lid or the like, it is usual to apply a baking coating treatment, but this baking coating treatment is generally 180 to 400 ° C. × 5 to 5 ° C. It is applied under the condition of about 1800 seconds.

[0043]

【Example】

Example 1 As shown in Table 1, the alloys of reference symbols A and B within the compositional range defined in the invention of claim 1 of the present application and the reference symbol C of the compositional composition corresponding to the conventional alloy JIS 5182 alloy are shown. For alloys, applying the process shown in Table 2,
A rolled plate having a final plate thickness of 0.3 mm was obtained. Here, in Table 2, the conditions of manufacturing process numbers 1 and 3 are within the process condition range of the invention of claim 3 of the present application, and the conditions of manufacturing process numbers 2, 4 and 5 are outside the process condition range.

[0044]

[Table 1]

[0045]

[Table 2]

Example 2 As shown in Table 3, alloys designated by reference symbols D and E within the compositional range defined by the invention of claim 2 of the present invention, and the compositional composition corresponding to the conventional alloy JIS 5182 alloy. Sign F of
By applying the process as shown in Table 4 to the alloy of No. 1 and No. 2 of No. 1, a rolled plate having a final plate thickness of 0.3 mm was obtained. Here, the conditions of the manufacturing process numbers 6, 7, and 9 in Table 4 are within the process condition range of the invention of claim 4 of the present application, the manufacturing process number 8,
The conditions of 10 and 11 are outside the process condition range.

[0047]

[Table 3]

[0048]

[Table 4]

For each rolled plate obtained by each of the above examples, the number of intermetallic compounds of 6 μm or more (per 0.2 mm ² ) and the number of intermetallic compounds of 1 μm or more on the surface were measured using an image analyzer. The average crystal grain size in the direction perpendicular to the rolling direction was investigated, and the specific resistance value at 20 ° C. was further investigated. The results are shown in Table 5.

Further, each rolled plate obtained in each of the examples was subjected to a heat treatment at 270 ° C. for 20 seconds in an oil bath as a heat treatment corresponding to continuous coating baking. With respect to the plate after this heat treatment, the proof stress in each in-plane direction was examined. Among the in-plane directions, the yield strength value in the direction of maximum yield strength (actually L direction) is shown in Table 6, and the yield strength value in the maximum yield strength direction and the yield strength value in the minimum yield strength direction (actually 45 ° direction) The difference is shown in Table 6.

Further, as in the above, with respect to each rolled plate subjected to a heat treatment equivalent to coating baking of 270 ° C. for 20 seconds, the ear ratio, Erichsen value, and skin roughness at the time of molding were examined, and a local overhanging test was conducted. The results are also shown in Table 6.

Here, the rough skin property means that each plate is actually formed into a can lid shape, and when no rough skin is observed in each part by visual observation, a mark of ○ is given, and rough skin is recognized. Is marked with a cross.

In the local overhanging test, as shown in FIG. 1, a punch 1 having a diameter φ = 2 mm and a tip curvature R = 1 mm was used, and a test material 3 was placed on a die plate 2 to carry out local overhang press forming. And punch length L from 1.0mm
The punch length was changed from 1.9 mm to 0.1 mm every 10 steps, and the punch length which was one step shorter than the punch length at which cracking occurred was indicated as the limit at which cracking did not occur. For example, if a crack occurs at the punch length L = 1.5 mm, it is displayed as 1.4 mm. Therefore, the larger the test value, the better the local overhang formability.

[0054]

[Table 5]

[0055]

[Table 6]

In each of the above examples, in the case of the comparative example of manufacturing process No. 2, since the cooling rate during casting was slow, the number of large intermetallic compounds of 6 μm or more in the final plate exceeded 100, and therefore, Local protrusion is inferior,
Further, since the number of fine intermetallic compounds having a size of less than 1 to 6 μm is relatively small, the formability expressed by the Erichsen value is also poor, and the earring ratio is large because the rolling ratio of the final cold rolling is high.

Further, in the case of the comparative example of manufacturing process No. 4, since the intermediate heat treatment is the gradual temperature rise and gradual cooling in the batch furnace, a sufficient yield strength (L-direction yield strength) after baking coating cannot be obtained, and the final plate Since the average grain size is large and the specific resistance value is small (there is a small amount of Mn and Fe in solid solution), the surface roughness and local overhanging property are poor, and the rolling ratio of the final cold rolling after the intermediate heat treatment is high. Ear ratio has also increased.

Also in the case of the comparative example of manufacturing process No. 8, as in the comparative example of manufacturing process No. 2, since the cooling rate at the time of casting is slow, if the number of large intermetallic compounds of 6 μm or more in the final plate is large. At the same time, the number of fine intermetallic compounds having a size of 1 to less than 6 μm was small, so that the moldability represented by the Erichsen value was poor, and the local overhanging property was also poor.

Further, in the case of the comparative example of manufacturing process No. 10, the cooling rate during casting was slow, the intermediate heat treatment was gradually heated and gradually cooled, and the final cold rolling rate was also large. In this case, the intermetallic compound in the final plate was All of the conditions, the average crystal grain size conditions, and the specific resistance value (Mn, Fe solid solution amount) conditions did not satisfy the range defined by the present invention, and the performance was generally poor.

On the other hand, manufacturing process No. 5 uses an alloy corresponding to the 5182 alloy which has been conventionally used as a lid material, and applies a conventional ordinary process with a slow casting speed. Since the number of fine intermetallic compounds of less than 6 μm is small, the difference in the proof stress direction is significantly large and the strength anisotropy is strong, and the formability represented by the Erichsen value is slightly inferior. He was also inferior.

The manufacturing process number 11 is also the same as the conventional 518.
Although an alloy corresponding to the two alloys was used and a process in which a normal casting cooling rate was low was applied, the result was almost the same as that of the manufacturing process No. 5 also in this case.

On the other hand, manufacturing process numbers 1, 3, 6,
In Examples 7 and 9 of the present invention, the intermetallic compound condition, the crystal grain size condition, and the specific resistance value (Mn, Fe solid solution amount) in the final plate
All the conditions satisfy the range specified in this invention,
In this case, a sufficient yield value is obtained as a yield value after baking, the strength anisotropy is small, and the ear ratio, skin roughness, and local overhanging property are good, and the moldability represented by the Erichsen value is also good. Met.

[0063]

As is clear from the above-mentioned embodiments, the aluminum alloy hard plate for molding according to the present invention has sufficient post-baking proof stress as a lid material for a two-piece aluminum can for applications where internal pressure is applied. Its strength anisotropy is small, its local overhanging property is excellent, its deep-drawing ear ratio is small, and it is also excellent in moldability such as rough skin and Erichsen value. Since it is close to the component composition of the 3004 alloy that has been conventionally used as, the aluminum can can be uni-alloyed with the lid material having the same component composition as the body material, or at least the lid material can have a component composition close to the body material, Therefore, it is not necessary to adjust the components even when redissolving the aluminum can for recycling, and the recycling can be performed at low cost. Furthermore, iron cans may be mixed in when recycling aluminum cans, but in the hard plate of the present invention, up to 2.5% of Fe is allowed without causing a decrease in performance. However, normally, there is no particular problem even if it is used as a lid material as it is, and from this point as well, it can contribute to facilitating the recycling of the aluminum can.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a mode of press molding for evaluating local overhang formability in Examples.

Claims (1)

Claims 1. Mg 0.5-3.0% (weight%, the same applies hereinafter), Mn 0.5-2.5%, Fe 0.1-2.5%,
The balance consists of Al and inevitable impurities, and
The specific resistance at ℃ is 4.5μΩcm or more, the average grain size in the direction perpendicular to the rolling direction is 100μm or less, and the number of intermetallic compounds of 6μm or more on the plate surface is 100 per 0.2mm ^2. An aluminum alloy hard plate for forming, characterized in that the number of intermetallic compounds having a size of 1 μm or more is 2000 or more per 0.2 mm ² . 2. Mg 0.5-3.0%, Mn 0.5-2.5%,
Fe 0.1-2.5% and Cu 0.05-1.0%, Z
n 0.1 to 1.0% of 1 type or 2 types, the balance is made of Al and unavoidable impurities, the specific resistance value at 20 ° C. is 4.5 μΩcm or more, and the direction perpendicular to the rolling direction is contained. The average grain size is 100 μm or less, the number of intermetallic compounds of 6 μm or more on the plate surface is 100 or less per 0.2 mm ^{2, and the} number of intermetallic compounds of 1 μm or more is 2000 or more per 0.2 mm ^2. An aluminum alloy hard plate for forming, characterized in that 3. Mg 0.5-3.0%, Mn 0.5-2.5%,
An alloy containing 0.1 to 2.5% of Fe and the balance of Al and unavoidable impurities is continuously cast at a cooling rate of 50 ° C./sec or more to form a continuously cast plate having a plate thickness of 3 to 15 mm, and then the continuously cast plate. After the first cold rolling on
Intermediate heat treatment in which the temperature is raised to a temperature in the range of 20 ° C at a heating rate of 10 ° C / sec or more, and immediately or at a temperature in the range is held for 120 seconds or less, and then cooled at a cooling rate of 10 ° C / sec or more. And subsequent cold rolling 1
One or two or more times, and the final secondary cold rolling has a rolling rate of 30% or more, whereby the specific resistance value at 20 ° C is 4.5 μΩcm or more, and the average crystal grain in the direction perpendicular to the rolling direction. Aluminum alloy having a diameter of 100 μm or less, and the number of intermetallic compounds of 6 μm or more on the plate surface is 100 or less per 0.2 mm ^{2, and the} number of intermetallic compounds of 1 μm or more is 2000 or more per 0.2 mm ^2. A method for producing an aluminum alloy hard plate for molding, which comprises obtaining a plate. 4. Mg 0.5-3.0%, Mn 0.5-2.5%,
Fe 0.1-2.5% and Cu 0.05-1.0%, Z
An alloy containing one or two of 0.1 to 1.0% of n and the balance of Al and inevitable impurities at 50 ° C. /
After continuously casting at a cooling rate of sec or more to obtain a continuously cast plate having a plate thickness of 3 to 15 mm, and then subjecting the continuous cast plate to primary cold rolling, the temperature is within the range of 500 to 620 ° C at 10 ° C /
Immediately after raising the temperature at a heating rate of sec or more and holding at a temperature within the range for 120 seconds or less, 10 ° C /
The intermediate heat treatment for cooling at a cooling rate of sec or more and the subsequent secondary cold rolling are performed once or twice or more, and the final secondary cold rolling reduction rate is set to 20% or more.
The specific resistance at 0 ° C is 4.5 µΩcm or more, the average grain size in the direction perpendicular to the rolling direction is 100 µm or less, and the number of intermetallic compounds of 6 µm or more on the plate surface is 100 per 0.2 mm ^2. Characterized by obtaining an aluminum alloy hard plate in which the number of intermetallic compounds of 1 or less and 1 μm or more is 2000 or more per 0.2 mm ² .
Manufacturing method of aluminum alloy hard plate for forming.