JPH089757B2 - Manufacturing method of aluminum alloy hard plate for forming - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aluminum alloy hard plate for forming and used which is subjected to a paint baking treatment, such as a can body of a two-piece aluminum can, that is, a DI body. Concerning the manufacturing method, it has particularly high strength, excellent moldability, low ear rate, and easy molding after paint baking.
The present invention relates to a method for manufacturing an Al-Cu-Mg-Mn-based aluminum alloy hard plate.

Conventional technology Aluminum alloy sheets for forming, especially aluminum alloy sheets used as can bodies for DI cans, have been made thinner in recent years in order to expect economic effects by using thinner sheets with higher strength. Higher strength is being promoted.
Various aluminum alloys have been conventionally used for this type of application, but in particular JIS 3004 which is an Al-Mg-Mn alloy.
The alloy hard plate shows relatively good formability even when subjected to cold rolling with a high rolling ratio to increase the strength, and therefore, it is often used for a can body of a DI can.

As a method for producing this 3004 alloy hard plate, after subjecting the ingot to homogenizing heat treatment, hot rolling is performed according to a conventional method, and then cold rolling is performed, or intermediate cold annealing is not performed. In many cases, the product sheet is subjected to the final cold rolling and then subjected to the final cold rolling. As the intermediate annealing in such a process, generally, a batch annealing in which a box annealing furnace is used and held at 300 to 400 ° C. for about 30 minutes to 3 hours is often applied. In this case, the rolling ratio of the final cold rolling is applied. Is usually 70% or more. In addition, with the spread of continuous annealing furnaces in recent years, rapid annealing, high-temperature short-time heating, and rapid cooling have become possible by applying continuous annealing to intermediate annealing. A process has also been proposed in which high strength can be obtained even if the rolling ratio is relatively low.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As the performance required for a can body of a DI can, in addition to having high strength as described above, it has excellent moldability and a low ear rate during DI processing. Is required. Furthermore, in the production of DI cans, there are the following problems because of the further forming process after the coating and baking process of the can body.

In other words, in the manufacture of DI cans, generally, after the can body is formed by DI processing, paint baking is performed, and then necking forming (mouth drawing) and flange forming (flange forming) to the edge of the can body. After that, the seaming is usually performed together with the can lid (the edge winding process). In this way, the edge of the can body will be subjected to further forming processing (necking forming, flange forming, seaming forming) after baking, but such coating baking treatment is required as the thickness of the can body material becomes thinner. There is a problem that the can body is likely to buckle during the subsequent molding process. That is,
The edge of the can body is easily work-hardened by the molding process after paint baking, but if this edge hardens, the processing load at each molding must be increased. The buckle is likely to occur. Therefore, it is desired that the body of the can has little work hardening after the paint baking treatment.

By the way, the problem with the conventional manufacturing method of the 3004 alloy hard plate as described above is that when performing intermediate annealing in a box-type annealing furnace,
It differs from when it is performed in a continuous annealing furnace.

That is, first, in the process using the continuous annealing furnace, it is difficult to control the earring ratio that occurs during DI processing, and therefore the rolling ratio of the final cold rolling after the intermediate annealing cannot be increased. In addition, in the case of materials produced by the continuous annealing process, the solid solution amount of alloying elements is larger than in the case of the box-type annealing process, and therefore the hardening by processing is large, and therefore precipitation hardening is also added during the molding of the DI can after the baking process. There is a problem that the amount of curing at the edge of the can body becomes large and molding becomes difficult. However, the material obtained by the continuous annealing process generally has fine recrystallized grains and is therefore excellent in formability.

On the other hand, in the process using the box-type annealing furnace, if the strength is to be increased, the final cold rolling rate must be increased, and if the final cold rolling rate is increased in this way, it is difficult to control the ear rate. Although various proposals have been made for controlling the ear rate in this case, there is a problem in that recrystallized grains become coarser and moldability tends to deteriorate. However, the material produced by this box-type annealing process has an advantage that the work hardening of the green part after the coating and baking treatment of the DI can hardly occurs.

This invention was made against the background of the above circumstances.
An object of the present invention is to provide a method for producing an aluminum alloy hard plate which has both excellent formability and strength, is easy to control the ear ratio, and has little work hardening after paint baking.

Means for Solving the Problem In the method of the present invention, basically, using an aluminum alloy plate of a specific component of Al-Mg-Mn-Cu system, a low recrystallization rate and fine in hot rolling. A large number of sub-crystal grains are generated, and subsequent recrystallization treatment is performed by rapid heating and short-time heat treatment to produce uniform and fine recrystallized grains, and then cold rolling is performed at an appropriate rolling rate to obtain strength,
An aluminum alloy hard plate having excellent formability, easy control of ear ratio, and little work hardening after paint baking is obtained.

Specifically, the manufacturing method of the aluminum alloy hard plate for forming of the present invention, Mg 0.5 ~ 1.8 wt%, Cu 0.5 wt% or less, Mn 0.6 ~ 1.8 wt%, Si 0.1 ~ 0.5 wt%, Fe0.2-1.0wt%
And the Fe / Si weight ratio is 3.0 or less, and the balance is
After casting an alloy consisting of Al and unavoidable impurities and subjecting the ingot to homogenization treatment, when performing hot rolling, the hot rolling rise temperature is set to 270 to 320 ° C and the rise plate thickness is 3 mm or less. In addition, hot rolling is performed so that the area ratio of recrystallized grains in the cross section of the hot rolled sheet is 30% or less and the area ratio of subcrystalline grains of 10 μm or less is 50% or more, and then 1 ° C / sec. 380 to 620 ℃ at the above heating rate
It is heated to a temperature within the range of 0 to 10 minutes and then recrystallized so that the recrystallized grain size is 150 μm or less in any region of the plate cross section, and then cooled at a rolling rate of 70 to 95%. It is characterized by performing hot rolling.

Action First, the reasons for limiting the components of the aluminum alloy in the present invention will be explained.

The alloy components shown below are added mainly for the purpose of enhancing the strength of the material and controlling the ear ratio and formability.

Mg: Mg coexists with Cu and Si, GP zone → β′Mg ₂ Si → β
It follows the precipitation process such as Mg ₂ Si or GP zone → S'Al ₂ CuMg → SAl ₂ CuMg and contributes to the strength improvement at the precipitation stage of the intermediate phase. Further, Mg is an element that contributes to the solid-melt strengthening by itself. Thus, Mg is an essential element for improving strength, but if Mg is less than 0.5 wt%, the effect of improving strength is small,
On the other hand, if it exceeds 1.8 wt%, there is no particular problem in draw forming, but it becomes easy to work and harden, so that redrawability, ironing workability, and further the formability of the green part of the DI can after paint baking is deteriorated. Therefore, the amount of Mg is set within the range of 0.5 to 1.8 wt%.

Cu: In the process of the present invention, it is possible to expect solution treatment of Cu during the recrystallization treatment, and therefore, if Cu is added, in the precipitation process of Al-Cu-Mg-based precipitates during coating baking treatment. Strength can be improved by utilizing age hardening. However, if Cu is added in excess of 0.5 wt%, age hardening can be easily obtained, but work hardening tends to occur during molding, which impairs formability.Therefore, the upper limit of Cu addition is 0.5 wt%. did. The lower limit of the Cu content is not specified, but if the Cu content is less than 0.1 wt%, the above-mentioned curing can hardly be expected, so it is preferable to add 0.1 wt% or more.

Mn: Mn is an element that contributes to the improvement of strength and is effective in improving the formability. In particular, in the can body material which is the main application in this invention, since severe ironing is carried out, and further, the molding is carried out at the edges even after the paint baking treatment, the addition of Mn for improving these moldability. Is important. Usually several μ
It is well known that intermetallic compounds of about m suppress work-hardening. Especially, compounds such as Mn and Fe cause work-hardening in subsequent molding when subjected to high-level processing such as ironing. It plays the role of making it harder and contributes to the improvement of moldability. On the other hand, emulsion type lubricants are usually used in the ironing of aluminum alloy sheets, but when the amount of Mn-based crystallized substances is small, an emulsion type lubricant with the same strength is used. In this case, the lubrication ability is insufficient, and there is a possibility that appearance defects such as scratches and seizure called "goring" may occur. Mn-based crystallized products bring about a solid lubricating effect during ironing and are effective in preventing the occurrence of appearance defects after ironing, but the effect affects the large amount, type, and type of crystallized products. To be done. When casting with a high cooling rate using the continuous casting method, Mn is 1.8w
Not only can it be cast without problems even if it is added in excess of t%, but the size of the crystallized substances can be adjusted by subsequent heat treatment, but in the DC casting method that is currently the mainstream, Mn is 1.8w.
If it is added in excess of t%, primary crystal giant intermetallic compounds of MnAl ₆ will be formed, and conversely, formability will be significantly impaired. Therefore, the upper limit of the amount of Mn added is set to 1.8 wt%. The Mn content is 0.6
If it is less than wt%, the above-described solid lubricating effect and work hardening suppressing effect of the Mn compound cannot be obtained, so the lower limit of the Mn content was set to 0.6 wt%.

Fe: Fe is an element necessary for promoting crystallization and precipitation of Mn together with Si, and controlling the amount of solid solution in the aluminum matrix and the dispersed state of Mn-based insoluble compound. It is necessary to set appropriate Fe content and Si content. Fe amount is 0.2w
If it is less than t%, it becomes difficult to obtain a proper compound dispersion state, while if the amount of Fe exceeds 1.0 wt%, the primary crystal giant intermetallic compound is generated together with the addition of Mn, and the formability is significantly impaired. There is a risk. Therefore, the Fe content is set within the range of 0.2 to 1.0 wt%.

Si: When Si is added, it is well known that age hardening can be expected even in the precipitation process of Mg ₂ Si-based compound,
The role of Si in the present invention lies not in improving the strength but in controlling the directionality during molding. That is, Fe is an element that may be positively added in order to make the recrystallized grains fine, but when Fe is a solid solution in the aluminum matrix, 45 °
It is preferable that Fe is not solid-dissolved in the aluminum matrix because ears are likely to occur. Si promotes the precipitation of Fe,
As a result, the solid solution amount of Fe in the aluminum base is reduced,
This improves the directionality of molding processability. Where Fe
If the / Si ratio (weight ratio) exceeds 3.0, the amount of Si becomes too small and the solid solution amount of Fe increases. When the Fe / Si ratio is 3.0 or less, the directionality can be improved by reducing the solid solution amount of Fe even when the intermediate annealing is a box-type annealing process. Therefore
It is necessary to determine the Si amount so that the Fe / Si ratio is 3.0 or less according to the Fe amount. Optimum F when the absolute amount of Si is less than 0.1 wt%
It is difficult to obtain the e / Si ratio, while if it exceeds 0.5 wt% Fe
The hardening that accelerates the precipitation of is saturated, and the age hardening by Mg ₂ Si proceeds, and the formability after the coating baking treatment deteriorates. Therefore, the absolute amount of Si is set within the range of 0.1 to 0.5 wt%.

The balance of the above components may basically be Al and inevitable impurities. In addition, in a usual aluminum alloy, a minute amount of Ti or Ti and B may be added for refining ingot crystal grains. In the case of the present invention, a small amount of Ti, or Ti and B is also contained. Good.
However, in the case of adding Ti, if less than 0.01 wt%, the effect of Ti addition cannot be obtained, while if it exceeds 0.2 wt%, primary TiAl ₃ crystallizes and impairs formability, so Ti is 0.01 to 0.2 wt%. It is preferably within the range. Also, when B is added together with Ti, if B is less than 1 ppm, the effect of B addition cannot be obtained.
Is more than 500 ppm, coarse particles of TiB ₂ are mixed and impair the moldability, so B is preferably in the range of 1 to 500 ppm. In addition, Be is set to 0 to prevent molten metal oxidation during casting.
You may add in the range of 02 wt% or less. Furthermore, trace elements such as Cr, Zn, V, and Zr may be contained as impurities.
0.3wt% or less, Zn0.1wt% or less, V0.3wt% or less, Zr0.3wt
If it is at most%, the effect of the present invention is not particularly impaired.

Next, the process in the method for manufacturing an aluminum alloy hard plate for forming according to the present invention will be described.

First, a molten aluminum alloy having the above-described composition is prepared by casting ordinary hot water according to a conventional method and casting. As a casting method, a general DC casting method (semi-continuous casting method) may be applied. For the obtained ingot. After heating as a homogenizing heat treatment, preheating before hot rolling is performed, or preheating before hot rolling that also serves as homogenizing heat treatment is performed, and then hot rolling is performed. The conditions for the homogenizing heat treatment are not particularly limited, but usually 500 to 620 ° C. and 1 to 20 hours may be used.

In hot rolling, the hot rolling temperature (temperature of finish rolling) is 270 to 320 ° C, preferably 280 to 310 ° C, and the rolled sheet thickness is 3 mm or less. In the recrystallized state of the hot rolled sheet in the hot rolled state, the area ratio of recrystallized grains in the cross section of the hot rolled sheet (hereinafter referred to as the recrystallization rate) is 30% or less and The area ratio occupied by subcrystal grains having a normal diameter of 10 mm or less (hereinafter referred to as subcrystal grain) in the cross section of the rolled sheet is controlled to be 50% or more.

Here, as is generally known, in hot working of aluminum alloys, dislocations are increased / accumulated by the initial work hardening, and as the dislocations increase, dislocation motion and slip are activated. The dislocation annihilation speed becomes equal to the generation speed, and the dislocation density reaches the equilibrium value. In the process, rearrangement of dislocations, that is, polygonization occurs, and a fine knitting structure (subcrystalline structure) divided by subgrain boundaries (small-angle grain boundaries) having a regular dislocation arrangement is generated. In this state, each fine region surrounded by subgrain boundaries is called a subgrain. Further, some of these sub-crystal grains grow and serve as nuclei for recrystallization, and the re-crystal grains grow from the re-crystal nuclei to generate a re-crystal grain structure. The above process continues until the hot working is finished and the hot rolled sheet is finally cooled to a temperature lower than the recrystallization temperature.

And in the present invention, the state of hot rolling, that is, the structure state in the state where the hot rolling is completed and the hot rolled sheet is cooled to the recrystallization temperature or lower, the recrystallization rate is as described above.
It is controlled to be 30% or less and a subcrystal ratio of 50% or more. Note that the recrystallization rate can be determined by observing the structure of the cross section of the hot rolled sheet with an optical microscope, and the area ratio of the sub-crystal grains also shows the structure state of the cross section of the hot rolled sheet with a transmission electron microscope. It can be determined by observing.

Generally speaking, the recrystallized state as described above is an unrecrystallized state or an incomplete recrystallized state close to it, but it can be said that a large number of fine subcrystal grains are generated. By keeping it in a recrystallized state,
A fine and uniform recrystallized structure can be obtained by the next recrystallization treatment. Such a recrystallized state can be achieved by regulating the hot rolling finish temperature as described above and by appropriately determining the rolling pass schedule, the interpass time, the rolling speed, etc. in the finish rolling stage. here,
If the hot rolling temperature is less than 270 ° C, it is difficult to obtain 50% or more of recrystallized grains under any rolling condition, while if it exceeds 320 ° C, the rolling after rolling under any rolling condition is difficult. Recrystallization rate exceeds 30%, and the surface and edge of the plate recrystallize, while the other parts (especially the central part in the thickness direction of the plate) become a recovery structure after annealing in that part. The recrystallized structure (after the recrystallization treatment after hot rolling) becomes coarse, and as a result, the structure becomes nonuniform in the coil, resulting in deterioration of formability. Therefore, the hot rolling temperature is set to 270 ° C or higher and 320 ° C or lower. Further, if the hot rolled sheet thickness exceeds 3 mm, in order to obtain a predetermined final sheet thickness, the rolling rate must be remarkably increased in cold rolling after the recrystallization treatment, which makes it difficult to control the ear rate. Become. Therefore, the hot rolled sheet thickness is set to 3 mm or less.

The rolled plate obtained by the hot rolling as described above, after cooling once, or as it is without cooling,
The temperature is raised to a temperature in the range of 380 to 620 ° C at a heating rate of 1 ° C / sec or more, and a recrystallization treatment is performed by holding at that temperature for 0 to 10 minutes, from the plate surface to the center in the thickness direction. A uniform and fine recrystallized structure with a recrystallized grain diameter of 150 mm or less is obtained in any part. If such a uniform and fine recrystallized structure is obtained, the formability is excellent even in the plate after the cold rolling thereafter. Further, by such a recrystallization treatment, a plate having a high ear of 0 to 90 ° C. at the time of forming can be obtained, and a 45 ° low ear material can be obtained even if the cold rolling rate thereafter is increased. this is,
Sub-crystal grains generated in the as-rolled state have many cubic orientations (cube orientations), and during subsequent heating for recrystallization treatment at a heating rate of 1 ° C / sec or more, the sub-grain orientations of the cube orientations Since the substance that suppresses growth does not precipitate,
Subgrains in that direction grow preferentially and recrystallize,
A plate with 90 ° high ears can be obtained. Here, if the temperature rising rate in the recrystallization treatment is less than 1 ° C./sec, it becomes difficult to form fine recrystallized grains of 150 μm or less in any portion in the plate thickness direction as described above, and the cube orientation The growth of subgrains may be hindered and it may be difficult to control the ear rate. If the recrystallization temperature is lower than 380 ° C, it becomes difficult to recrystallize sufficiently, while if it exceeds 620 ° C, eutectic melting may occur and a coarse recrystallization rate may occur. Also, if the holding time exceeds 10 minutes, recrystallized grains may grow and become coarse. The recrystallization treatment at such a temperature rising rate of 1 ° C./sec or more can be achieved by heating using a continuous annealing furnace.

70% or more 95% after recrystallization as described above
The final strip thickness is obtained by cold rolling at a rolling rate of not more than%. This cold rolling is necessary to obtain the required final strip thickness. Here, in the alloy component system used in the present invention,
When the cold rolling rate after the recrystallization treatment is 70% or more, work hardening is less likely to occur during the molding process after the coating and baking treatment for the can body. Further, according to the conditions of hot rolling and recrystallization treatment applied in the present invention, after the recrystallization treatment
Even if cold rolling of 70% or more is performed, it is possible to avoid deterioration in ear ratio.

The cold-rolled sheet obtained by cold rolling as described above may be used as a final sheet as a product as it is, but if the formability such as deep drawing is further emphasized, it is further 90 to 150 after cold rolling. The final annealing may be performed at a low temperature of ° C. If the temperature of this final annealing is higher than 150 ° C, it will harden during the paint baking process, and the processing load will need to be increased during subsequent necking molding, flange molding, and seaming molding. The effect of improving the formability cannot be obtained by the final annealing.

As described above, it has excellent formability such as strength and directionality (ear ratio), drawability, redrawability, and ironing formability. Moreover, it does not work harden during molding after coating baking processing, and its coating It is possible to obtain an aluminum alloy hard plate having good formability in necking forming, flange forming, and seaming forming after baking treatment.

Example Alloys A within the composition range of the present invention as shown in Table 1
C and alloy D outside the compositional range of the composition of the present invention were DC-cast according to a conventional method, and the obtained ingot was subjected to homogenizing heat treatment at 600 ° C. for 6 hours and then hot-rolled. The hot rolling is performed such that the rising plate thickness and the rising temperature satisfy the conditions shown in the manufacturing process numbers 1 to 8 in Table 2, and by adjusting the rolling pass schedule, the pass time, and the rolling speed, Similarly, as shown in Table 2, the recrystallization rate in the hot-rolled sheet and the sub-crystallization rate of 10 μm or less were obtained. Then, in the case of manufacturing process Nos. 3 to 7, immediately after hot rolling, and in the case of manufacturing process Nos. 1, 2 and 8, primary cold rolling was performed to obtain the plate thickness shown in Table 2
Recrystallization treatment was performed under the conditions shown in the table. The maximum grain size after recrystallization treatment is shown in Table 2. Then, cold rolling was performed to obtain final plates each having a plate thickness of 0.30 mm. Corresponds to paint baking for each plate obtained in this way
In addition to examining the yield strength after heat treatment (baking) at 200 ° C for 20 minutes, the earring ratio in drawing forming was investigated as the directionality.
Furthermore, the formability in DI processing, the proof stress of the edge after baking as described above after DI processing, and the necking formability (the degree of wrinkling) when necking is applied to the edge, necking molding Table 3 shows the results of examining the maximum load required for

In Table 3, the DI moldability and necking moldability (degree of wrinkle formation) are evaluated based on the No. 1 process, which corresponds to the conventional general process, and are evaluated as good (○).
And △ when it is slightly inferior, and × when the defect rate is extremely bad.
Marked. In addition, the directivity (ear ratio) is 58mm blank diameter.
Under the conditions of φ, punch diameter of 32 mmφ, and clearance of 45%, deep drawing was performed without ironing and the characteristics of the material were apt to appear, and the ear ratio after deep drawing was examined. Further, the necking load was examined under the conditions of a draw ratio of 4% and a clearance of 20%.

As is clear from Table 3, the aluminum alloy rolled plates according to No. 5 and No. 7 manufactured according to the conditions of the present invention using the alloys within the compositional range of the present invention deviate from the conditions of the present invention. No. 1 to No. 4, N manufactured under comparative conditions
Compared with the rolled plate according to o.6, it has better earing rate and DI
Formability is equivalent. On the other hand, in No. 8 rolled plate made of an alloy out of the compositional range of the present invention, although high strength is easily obtained, the yield strength after coating baking treatment required when thinned as a can body material is 28.5 kgf / When a high-strength material exceeding mm ² was used, it was impossible to perform molding after DI processing because of poor moldability. In addition, all the rolled sheets of No. 1 to No. 7 were adjusted so that the yield strength after painting and baking was 28.5 kg / mm ² or more. And the yield strength when paint baking is performed after DI processing is 0.6-0.7 kgf / mm for materials with a cold rolling rate of 70% or more after recrystallization (No.2 to No.7). The difference was 1.2 kgf / mm ² or more for the materials (No. 1 and No. 8) whose cold rolling rate after recrystallization treatment was less than 70%, while it was as small as about ² . It can be seen that when the cold rolling rate after the recrystallization treatment is 70% or more, the work hardening during the subsequent forming process is reduced. Furthermore, comparing No. 1 according to the comparison conditions with No. 7 according to the conditions of the present invention, it is possible that No. 7 according to the conditions of the present invention has a higher proof strength of 1.2 kgf / mm ^{2 at the} edge. On the contrary, the necking load is reduced, which means that according to the conditions of the present invention, it is possible to secure good formability after the coating baking treatment without deteriorating the formability after the coating baking treatment. Regarding the crystal grain size after recrystallization, the maximum grain size is 150 μm or less (No.
1, No. 2, No. 4, No. 5, No. 7), the maximum particle size is 150 μm
Necking moldability is better and wrinkles are less than those of materials exceeding No. 3 (No. 3, No. 6). Therefore, paint baking is possible by making the particle size after recrystallization treatment 150 μm or less at the maximum. It is obvious that the moldability after treatment can be excellently achieved.

EFFECTS OF THE INVENTION As is clear from the above examples, according to the manufacturing method of the present invention, the moldability is good and has high strength, and the directionality is good and the earring rate during molding is low, Further, it is possible to obtain an aluminum alloy hard plate with less work hardening during the forming process after the paint baking process. If the method of the present invention is applied to the production of DI can body for 2-piece cans, in particular, not only the moldability during DI processing is excellent, but also the strength after paint baking is increased for thinning. However, since there is little work hardening during the subsequent molding process, the moldability during necking molding, flange molding, and seaming molding for the edge of the can body can be improved to prevent the occurrence of molding defects. Since the load is small, it is possible to prevent the can body from buckling during molding. Therefore, the manufacturing method of the present invention is particularly suitable for manufacturing can bodies for DI cans, but of course it can be applied to manufacturing other hard plates for molding.

Claims (1)

[Claims] 1. Mg 0.5 to 1.8 wt%, Cu 0.5 wt% or less, Mn 0.6 to
Contains 1.8wt%, Si0.1-0.5wt%, Fe0.2-1.0wt%,
In addition, after casting an alloy having a weight ratio of Fe / Si of 3.0 or less and the balance of Al and unavoidable impurities and subjecting the ingot to homogenizing heat treatment, hot rolling is performed before hot rolling. Increase the plate thickness as the temperature rises to 270-320 ℃
Hot rolling is performed so that the area ratio occupied by recrystallized grains is 30% or less and the area percentage occupied by sub-crystal grains of 10 μm or less is 50% or more in the cross section of the hot rolled sheet,
Then, heat at a temperature rising rate of 1 ℃ / sec or more to a temperature in the range of 380 to 620 ℃ and hold for 0 to 10 minutes to recrystallize so that the recrystallized grain size becomes 150 μm or less in any region of the plate cross section. The aluminum alloy hard plate for forming is excellent in strength, earring rate and formability and has less work hardening in forming, which is characterized by performing crystallization treatment and cold rolling at a rolling rate of 70 to 95%. Production method.