JP3278130B2 - Method for producing high-strength heat-treated aluminum alloy sheet for drawing - 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 heat-treated aluminum alloy sheet for drawing which requires high strength, and more particularly to a can body material, a can lid material and a food can (DRD can) for an aluminum two-piece DI can. The present invention relates to a method for producing an aluminum alloy plate for drawing used mainly as a container material.

[0002]

2. Description of the Related Art Aluminum containers which have been drawn and used include two-piece DI cans formed by being subjected to DI processing (drawing and ironing) and DRD processing (drawing and redrawing). There are DRD cans (food cans) which are formed by molding and other various deep drawn cans. Among these aluminum cans, the most typical method for producing DI cans is to deep-draw and iron the can body material.
After performing I processing to obtain a can body shape, trimming it to a predetermined size, then applying paint baking processing, and then necking (mouth drawing) and flange processing (mouth opening processing) on the can body edge ), And then a seaming process (sealing process) is usually performed by combining the separately formed can lids (can ends). As described above, since various types of processing are performed in the production of DI cans, etc., a balance between various workability such as deep drawing property, ironing property, mouth drawing property, mouth spreading property, overhang property and strength. Therefore, the material is selected and studied.

Among the various aluminum cans described above, JIS 3004 alloy and AA3104 alloy H19 or H39 are frequently used for the body of the DI can, and JIS is used for the can lid of the DI can. H of 5052 alloy, JIS 5082 alloy, JIS 5182 alloy
18 or H38 materials are frequently used, and DRD
JIS 5052 alloy H1 for cans and other deep drawn cans
Eight materials, H38 materials, and H38 materials of AA5042 alloy are frequently used.

[0004]

With respect to aluminum cans represented by aluminum two-piece DI cans, it is strongly desired to further reduce the thickness in order to reduce material costs. Therefore, materials for these aluminum cans that have a sufficiently high strength even if the thickness is reduced and that can secure excellent formability such as excellent drawability are desired. However, in the case of the conventional aluminum alloy plate for an aluminum can as described above, for example, in the case of an alloy plate for a can body, during baking treatment at 200 ° C. for about 20 minutes after the can manufacturing, and in the case of an alloy plate for a can lid, Since softening occurs during the previous baking process at about 270 ° C. for about 20 seconds, the finally obtained strength is at most about 300 N / mm ^2. Therefore, the strength is insufficient to reduce the thickness. Would.
Further, based on the above-mentioned conventional alloy system, for example, C
It is conceivable to improve the strength by adding a strengthening element such as u or by increasing the cold working ratio of the material, but in that case, the formability is significantly reduced, and as a can material Becomes inappropriate.

By the way, among various aluminum alloys, 2000 (Al-Cu-Mg) or 7000 series
Heat-treatable alloys of the Al-Zn-Mg type can be used as structural materials requiring high strength, since high strength exceeding 400 N / mm ² can be obtained with a proof stress. In this case, it is usually used in the state of solution treatment or in the state of being subjected to artificial aging treatment, and even if it is formed, it is only a very slight processing. When these heat-treated alloys are used for applications that require strong forming, they are formed in the state of a soft material and then subjected to a solution treatment or an artificial aging treatment to secure the strength. However, such a process is unsuitable as a material for cans. In any case, these conventional heat-treated alloys, although having sufficiently high strength, are inferior in formability, especially drawability, ironing property, overhanging property after the solution treatment, and are therefore applied to can materials. That was not considered.

[0006] Further, in the case of a material for a body of a DI can, not only high strength and excellent DI formability (drawing workability, ironing workability) are required, but also a DI can body is formed and subjected to a paint baking treatment. Formability in necking, flange processing and seaming after application is also required. As the thickness of the flange has been reduced along with the recent reduction in the thickness of the can body, the flange has been easily broken during flanging and seaming, thus improving the frangibility and seamability. In addition, there is a demand for a reduction in the diameter of the neck in order to reduce the weight of the can lid, and therefore an increase in the amount of necking is required. Therefore, further improvement in the formability of the flange portion is required. Further, in the case of a can lid material, it is desired to further improve not only the deep drawing property but also the overhang property and the opening property.

The invention of the present application has already been disclosed in Japanese Patent Application No. Hei.
No. 3899 proposes "a high-strength heat-treated aluminum alloy sheet for drawing and a method for producing the same".
This proposal basically relates to a heat treatment type DI can alloy based on a 7000 series alloy and a heat treatment method thereof. Specifically, Zn 3 to 6 wt%, Mg 0.5
-3% by weight, Mn more than 0.5% by weight and 1.5% by weight or less, with the balance being Al and unavoidable impurities.
I can alloy, or in addition to the above alloy elements, CuO.
At the same time as proposing alloys for DI cans to which 1 to 2.5 wt% is added, these alloys are finished to a predetermined thickness, and then within the range of 450 to 550 ° C. or 450 to 550 ° C.
Solution treatment at a temperature within the range of 40 ° C.
%, And a method of performing cold rolling at a rolling rate of 75% or less.

According to the above proposal, it is possible to secure high formability such as drawability at the same time as exhibiting high strength as a heat-treatable alloy, and to satisfy the above-mentioned various requirements. However, after further study for practical application, the above proposed alloy is unique to the heat-treated alloy during the period of storage, such as storage between the production of the sheet material at the material manufacturer and the canning at the manufacturer. Due to the aging, the strength of the material, especially the proof stress, increases.Therefore, if a long period of time elapses from plate manufacturing to can making, there is a problem that the formability such as ironing property at the time of can making deteriorates. It has been found that there is a problem that the strength and moldability at the time of can making vary depending on the period up to the later can making.

The present invention has been made in view of the above circumstances, and can satisfy the above-mentioned various requirements, and at the same time, there is little change with time after the manufacture of the plate, and after a long time has passed since the manufacture of the plate. It is an object of the present invention to provide a method for producing an aluminum alloy sheet for drawing, which is less likely to cause a reduction in molding workability such as ironing property and a variation in material properties even in the case of can making.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive experiments and studies, and as a result, by appropriately determining the manufacturing process and the manufacturing conditions for the alloy having the above-mentioned component composition. The present invention has found that not only can a heat-treatable alloy exhibit high strength and at the same time ensure good formability such as drawing workability, but also provide an aluminum alloy plate with little change over time after plate manufacture. Was reached.

More specifically, the method for producing a high-strength heat-treated aluminum alloy sheet for drawing according to the first aspect of the present invention comprises the steps of:
3-6%, Mg 0.5-3%, Mn more than 0.5%
After finishing an alloy containing 5% or less and the balance consisting of Al and unavoidable impurities to a predetermined thickness, 450-55
A solution treatment at a temperature in the range of 0 ° C. for 5 minutes or less, an artificial aging treatment at a temperature in the range of 80 to 150 ° C. for 1 to 24 hours, and a cold rolling at a rolling reduction of 70% or less It is characterized by rolling.

Further, the method for producing a high-strength heat-treated aluminum alloy sheet for drawing according to the second aspect of the present invention is characterized in that:
%, Mg 0.5-3%, Cu 0.1-2.5%, Mn
After finishing an alloy containing more than 0.5% and not more than 1.5% and the balance consisting of Al and unavoidable impurities to a predetermined plate thickness, a solution of not more than 5 minutes at a temperature in the range of 450 to 540 ° C. Aging treatment, followed by artificial aging treatment at a temperature in the range of 80 to 150 ° C. for 1 to 24 hours, and cold rolling at a rolling reduction of 70% or less.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in terms of the composition of components, as a heat-treatable alloy, the strength is enhanced by precipitation hardening by Zn and Mg, and M
The addition of n improves the stability of the structure and the workability of ironing, and further improves the strength by solid solution strengthening by adding Cu as necessary, and shortens the time of solution treatment from the viewpoint of the manufacturing process. The time is set so that sufficient formability as a material for drawing processing is ensured, and at the same time, an aging treatment under appropriate conditions after the solution treatment is carried out to suppress a temporal change after the production of the plate.

First, the reasons for limiting the component composition in the present invention will be described.

Zn: Zn forms MgZn ₂ together with Mg and is effective for improving strength by precipitation hardening. If the amount of Zn is less than 3%, the effect of improving the strength cannot be sufficiently obtained, while if it exceeds 6%, the rolling property is reduced, the moldability of the can is also reduced, and the corrosion resistance is further reduced. Therefore Zn
The amount was in the range of 3-6%.

Mg: Mg forms MgZn ₂ together with Zn and is effective in improving the strength by precipitation hardening. Also M
g alone is effective for improving strength by solid solution strengthening.
If the Mg content is less than 0.5%, the effect of improving the strength cannot be sufficiently obtained, while if it exceeds 3%, the rollability decreases, and
Decreases can moldability. Therefore, the amount of Mg is 0.5-3.
%.

Mn: Mn is an element effective for refining and stabilizing crystal grains, and improves ironing workability by a solid lubrication effect of a Mn-based intermetallic compound. When the Mn content is 0.5% or less, these effects cannot be sufficiently obtained. On the other hand, when the Mn content exceeds 1.5%, a primary crystal giant intermetallic compound of MnAl ₆ is generated, and the formability, particularly the flange formability, is remarkably improved. And the Mn-based intermetallic compound is MgZn.
₍₂₎ Precipitates are non-uniformly and coarsely deposited, making it impossible to improve strength. Therefore, the Mn content exceeds 0.5%.
It was within the range of 5% or less.

Cu: Cu is an element effective for improving the strength by solid solution strengthening. Therefore, Cu is positively added in the alloy according to the second aspect of the present invention. If the Cu content is less than 0.1%, the effect of improving the strength cannot be sufficiently obtained, while if it exceeds 2.5%, moldability and corrosion resistance deteriorate. Therefore, claim 2
In the invention of (1), the Cu content was in the range of 0.1 to 2.5%. In the alloy according to the first aspect of the present invention, it is needless to say that Cu may be contained as an impurity in an amount of less than 0.1%.

In addition to the above elements, Al and unavoidable impurities may be basically used. Common impurities include Fe, Si, Cr, Zr and the like.
%, Si is less than 0.5%, Cr is less than 0.3%, Z
If r is less than 0.3%, the effect of the present invention is not impaired. In general aluminum alloys, a small amount of Ti may be added alone or in combination with B to refine the ingot structure. Ti and B may be contained as impurities. Ti is less than 0.2%,
If B is less than 0.05%, the effect of the present invention is not particularly impaired.

Next, the manufacturing process according to the present invention will be described.

The steps until the alloy having the above-mentioned composition is finished to a predetermined intermediate plate thickness (the process before the solution treatment) are not particularly limited, but are usually cast by DC casting (semi-continuous casting). After that, a homogenization treatment is performed, hot rolling is further performed, and cold rolling is performed as necessary, so that a predetermined intermediate plate thickness is obtained. Alternatively, a continuous casting method may be applied, and if necessary, homogenization treatment and cold rolling may be performed to obtain a predetermined intermediate plate thickness.

Here, DC casting may be performed according to a conventional method. Also, the homogenization treatment is performed at 400 to 500 ° C. according to a conventional method.
Heating for about 1 to 24 hours. If the heating time of the homogenization treatment is less than 1 hour and the heating temperature is less than 400 ° C., none of the effects of homogenization can be obtained.
If the heating time exceeds 500 ° C., the effect of homogenization is saturated and the economic efficiency is impaired. If the heating temperature exceeds 500 ° C., local melting due to eutectic melting may occur.

Immediately after the homogenization treatment, or after preheating before hot rolling, hot rolling is performed. In this hot rolling, the starting temperature is in the range of 400 to 500 ° C. and the ending temperature is It is preferable to be in the range of 200 to 350 ° C. If the hot rolling start temperature is lower than 400 ° C., the deformation resistance is large and the rollability is deteriorated. On the other hand, if the hot rolling start temperature exceeds 500 ° C., hot rolling cracks may occur. It is desirable that the hot rolling be started at a temperature equal to or higher than the homogenization treatment temperature, and thereby, formation of coarse precipitates after the homogenization treatment can be suppressed.
If the hot-rolling end temperature is lower than 200 ° C., it is difficult to perform rolling. On the other hand, if the hot-rolling end temperature is higher than 350 ° C., uneven coarse precipitation of the intermetallic compound is promoted after hot rolling, and thereafter, , The solution-treating property of the powder decreases, and furthermore, the drawability, the overhang property, and the opening property are deteriorated.

On the other hand, when the continuous casting method is applied, a method of directly injecting a molten metal between rolls and solidifying it (a continuous casting method of a thin plate), or a method of injecting a molten metal between belts and blocks to solidify the same. May be applied, and in any case, hot rolling may be performed as necessary. When the continuous casting method is applied, the thickness of the cast plate is preferably in the range of 1 to 10 mm. If the thickness of the cast sheet is less than 1 mm, casting is difficult. On the other hand, if the thickness exceeds 10 mm, the load of the subsequent cold rolling to the product sheet thickness increases, and mass productivity decreases.

The cold rolling performed after hot rolling or continuous casting to obtain an intermediate sheet thickness as necessary may be performed according to a conventional method, and the rolling ratio is not particularly limited.

After finishing to the intermediate plate thickness as described above, a solution treatment is performed. This solution treatment is performed at 450 to
It is necessary to heat at a temperature in the range of 550 ° C or a temperature in the range of 450 to 540 ° C for a short time of 5 minutes or less.
If the solution treatment temperature is lower than 450 ° C., the elements that contribute to the strength improvement due to aging precipitation become insufficiently solutionized, so that sufficient strength improvement cannot be achieved. Further, in the case of the alloy of claim 1 in which Cu is not positively added, eutectic melting may occur if the solution treatment temperature exceeds 550 ° C., while Cu is positively added. In the case of the alloy (1), since the melting point is lowered by adding Cu, if the solution treatment temperature exceeds 540 ° C., eutectic melting may occur. Furthermore, this solution treatment reduces the processing time to 5 times.
It is important to use a short time of not more than a minute to achieve incomplete solution. That is, in general, the minimum time for the solution treatment of the 7000 series heat-treated alloy is specified in JIS 4000 in relation to the plate thickness, but the solution treatment is performed for a long time in accordance with JIS to complete the solution treatment. In such a case, although high strength is obtained, not only the subsequent cold rolling property is reduced, but also the formability of the can such as drawability and overhang is deteriorated.
In addition, if the solution treatment is performed for a long time, the surface oxide film becomes thicker, which deteriorates the formability, especially the ironing property. Therefore, it is necessary to perform a surface cleaning treatment such as alkali cleaning or acid cleaning after the solution treatment. This leads to an increase in cost. On the other hand, if the solution heat treatment time is set to 5 minutes or less and incomplete solution heat treatment is performed, the strength required for thinning the can can be increased, but the drawability, overhang property, ironing property, etc. Can moldability can be sufficiently ensured, and surface cleaning treatment after solution treatment is not required. Such a short-time solution treatment can be easily performed by using a continuous annealing furnace. The cooling rate after the solution treatment was 10 ° C.
/ Sec or more is sufficient. Therefore, for cooling after the solution treatment, not only water quenching but also forced air cooling can be applied.

After the solution treatment, an artificial aging treatment is performed at a temperature in the range of 80 to 150 ° C. for 1 to 24 hours. By applying such an artificial aging treatment, fine precipitates are generated, the working strain is homogenized, the material strength is improved, and the strength given by the final final cold rolling is stabilized. In addition to improving cold rollability, the change over time of the final sheet is particularly suppressed, and even if a long time has passed until can making, there is little decrease in formability during can making, and the progress up to can making Variations in strength and moldability over time can be reduced. That is, when the final cold rolling is performed as it is after the solution treatment, a change with time occurs after the plate is manufactured, and the strength at the time of can making increases and the formability decreases. However, by performing artificial aging treatment after the solution treatment and generating fine precipitates in advance, precipitation of fine precipitates during the standing period at the time of plate manufacturing is reduced, and The change can be prevented. Here, when the temperature in the artificial aging treatment is less than 80 ° C. or the holding time is less than 1 hour, the above-mentioned effects cannot be sufficiently obtained. On the other hand, when the temperature exceeds 150 ° C. or the holding time exceeds 24 hours, the overaging is performed. As a result, the strength is reduced. Therefore, the artificial aging treatment was specified at a temperature of 80 to 150 ° C. for 1 to 24 hours.

After the solution treatment, it is preferable that the artificial aging treatment is not immediately performed, but left at room temperature for one day (24 hours) or more to allow the room temperature aging, and then the artificial aging treatment is performed. If the room temperature aging is performed for 24 hours or more before the artificial treatment as described above, fine precipitates generated during the room temperature aging densify the precipitate distribution by the subsequent artificial aging treatment, and as a result, in the subsequent cold rolling. An effect of homogenizing introduced dislocations (processing strain) can be obtained.

After performing the artificial aging treatment as described above, cold rolling is performed to obtain the final sheet thickness. This final cold rolling needs to have a rolling reduction of 70% or less.
If the rolling ratio exceeds 70%, high strength can be obtained, but formability is significantly reduced, and the ear ratio in deep drawing becomes large. Although the lower limit of the rolling reduction in the final cold rolling is not particularly defined, it is preferably at least 30% in order to obtain a sufficiently high strength.

After finishing to a product thickness by final cold rolling, if necessary, final annealing may be performed at a temperature in the range of 80 to 160 ° C. for 1 to 12 hours. By performing such final annealing, the strain can be stabilized, and the deep drawability can be further improved. If the temperature of the final annealing is less than 80 ° C. and the time is less than 1 hour, the above effects cannot be obtained. On the other hand, if the final annealing temperature exceeds 160 ° C., overaging occurs and the strength is reduced, and if the final annealing time exceeds 12 hours, the strength becomes too high and the formability is increased.
In particular, drawability, ironability, and flange formability deteriorate, and in this case, depending on the temperature, overaging occurs, resulting in a decrease in strength. Since recent cold rolling mills are under high-speed and high-pressure conditions, the ascending temperature often exceeds 100 ° C. In this case, even if active heating is not particularly performed, the winding coil during cooling immediately after cold rolling is not required. Final annealing can be performed by self-annealing.

[0031]

EXAMPLE Alloy No. 1 in Table 1 was used. The alloys 1 and 2 were cast by a DC casting method according to a conventional method, and 4
Apply homogenization treatment at 60 ° C x 12 hours, 470 ° C after facing
To start hot rolling to obtain a hot-rolled sheet having a thickness of 3 mm. Further, alloy No. 1 in Table 1 was used. The alloy No. 3 was continuously cast and rolled to a thickness of 5 mm, and then subjected to a homogenization treatment at 460 ° C. × 12 hours. On the other hand, alloy No. No. 4 is a conventional material equivalent to JIS 3004 alloy.
After homogenization at 5 ℃ for 5 hours, after facing,
It was hot rolled to a thickness of mm.

The hot-rolled sheet (or continuous cast and rolled plate) thus obtained was subjected to production condition codes A to K in Table 2.
Under the conditions shown in the following, primary cold rolling → solution treatment → artificial aging treatment → secondary cold rolling → final annealing was performed. The artificial aging treatment or the final annealing was omitted in some of the production condition codes B, E, and G to I, and the artificial aging treatment was not performed in the production condition K for the conventional material (alloy No. 4).

With respect to each plate obtained as described above,
In addition to examining the mechanical performance, the characteristics of the DI can were examined. Table 3 shows the results. In addition, as for the mechanical performance, the tensile strength (in the state immediately after the production of the plate as described above (immediately after the artificial aging treatment)) and the state in which the coating was heated at 200 ° C. for 20 minutes as a coating baking treatment thereafter were used. TS), yield strength (YS), and elongation (EL) were examined. On the other hand, the characteristics of DI cans were examined for can-manufacturability, flange formability, compressive strength, and appearance quality, and evaluated in comparison with conventional materials (alloy No. 4; production condition code K). And 印 for excellent, and x for poor. Here, the can-making properties were evaluated by continuously forming 4000 cans of a DI can body and evaluating the rate of occurrence of breakage in the DI processing, and the flanging workability was performed by necking the DI can body after the DI processing. rear,
The conical punch is pushed in, and the opening rate at the time of fracture of the flange portion is evaluated. The pressure resistance is evaluated by applying internal pressure to the DI can and the pressure when buckling occurs. Evaluation was made based on the occurrence of flow lines and the degree of gloss.

Further, alloy No. 1 shown in Table 1 was used. As for the alloy No. 1, as a time-dependent change in the material properties of each plate manufactured by the processes indicated by the manufacturing condition codes A to D in Table 2, the first day and the third day immediately after the plate manufacturing (immediately after final annealing) , On the seventh day, the first month, and the sixth month. Table 4 shows the results. In addition, in Table 4, the "proof stress increase amount" represents the difference between the proof stress after 6 months and the proof stress on the first day. As the evaluation, when the increase in proof stress was within 10 N / mm ² ,
A cross mark was given when the value exceeded 10 N / mm ² .

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

As shown in Table 3, when an alloy (alloy No. 1 to No. 3) within the component composition range specified by the present invention was manufactured under conditions within the process range specified by the present invention, (Production condition codes A, G, J) have achieved higher strength than conventional materials (alloy No. 4, production condition code K: 3004 alloy), and have the same or better DI can characteristics. Was confirmed.

On the other hand, the manufacturing condition code C is a comparative example in which the temperature of the artificial aging treatment is too high, and the manufacturing condition code E is a comparative example in which the time of the artificial aging treatment is too long. Also, the flange formability was poor. The production condition code F is a comparative example in which the rolling reduction in the final cold rolling was too high. In this case, the strength was too high and the can-making property was poor, and the ear ratio after DI processing was high. The production condition code H is a comparative example in which the solution treatment temperature was too high.
In this case, the drawability was reduced due to the occurrence of eutectic melting, and the appearance quality was poor due to the occurrence of flow lines on the surface of the DI can. The production condition code I is a comparative example in which the solution treatment time was too long, but in this case, the can-making property was reduced and the appearance was poor due to the generation of flow lines due to the oxide film.

Table 4 shows the change over time in the material properties.
As shown in the above, in the case of the manufacturing condition code A manufactured under the process conditions specified in the present invention for the alloy within the component composition range specified in the present invention, the increase in the yield strength value is only 7 N / mm ² even after 6 months. It can be seen that the material has stable material properties. On the other hand, the production condition code B is a comparative example in which the artificial aging treatment was not performed after the solution treatment, and the production condition code D was a comparative example in which the temperature of the artificial aging treatment after the solution treatment was too low. It was found that the increase in proof stress after a lapse of one to six months was remarkably large, and the ironing property was also reduced.

[0042]

As is clear from the above embodiments, according to the present invention, as an aluminum alloy sheet for drawing used for various cans, etc., not only high strength but also excellent formability, In particular, it has become possible to obtain an aluminum alloy sheet having excellent drawability and ironing property, with little change over time, and stable material properties for a long time. That is, a conventional Al-Mn-Mg-Cu alloy or Al-Mg
-In Mn-based alloys, it was said that if the strength was increased, the drawability and ironability would decrease, but in the case of the present invention, the component composition was strictly specified, and further, by applying appropriate solution treatment conditions as a heat treatment type alloy. By optimizing the solid solution precipitation state of alloying elements, it is possible to ensure good formability while increasing strength, and by performing appropriate artificial aging treatment after solution treatment, heat treatment type This makes it possible to suppress the time-dependent change peculiar to the alloy. Therefore, if the aluminum alloy plate according to the present invention is used, particularly as a material for a can, it becomes possible to make the material thinner and have a higher strength. In particular, even when a long period of time elapses from plate manufacturing to can making, a reduction in moldability during can making can be prevented, and can can be made stably. Further, the aluminum alloy plate according to the method of the present invention is applicable not only to DI cans and DRD cans, but also to can lids, and thus can be made into a unialloy can, so that recyclability can be improved.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22F 1/04-1/057 C22C 21/00-21/18

Claims (2)

(57) [Claims] 1. Zn 3 to 6% (% by weight, hereinafter the same), M
After finishing an alloy containing 0.5 to 3%, Mn of more than 0.5% and 1.5% or less, and the balance consisting of Al and unavoidable impurities to a predetermined thickness, the temperature is in the range of 450 to 550 ° C. Solution treatment at a temperature of 5 minutes or less, and then 80-1
Manufacture of a high-strength heat-treated aluminum alloy sheet for drawing, which is subjected to an artificial aging treatment at a temperature in the range of 50 ° C. for 1 to 24 hours, and further to a cold rolling at a rolling reduction of 70% or less. Method. 2. 3 to 6% of Zn, 0.5 to 3% of Mg, Cu
After finishing an alloy containing 0.1 to 2.5%, Mn of more than 0.5% and 1.5% or less, and the balance consisting of Al and unavoidable impurities to a predetermined plate thickness, a range of 450 to 540 ° C. Solution treatment for 5 minutes or less at a temperature within
Manufacture of a high-strength heat-treated aluminum alloy sheet for drawing, which is subjected to artificial aging treatment at a temperature in the range of 150 ° C. for 1 to 24 hours, and further to cold rolling at a rolling rate of 70% or less. Method.