JPH0747805B2 - Manufacturing method of aluminum alloy hard plate for forming with low ear rate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an aluminum alloy hard plate for forming, which is used as, for example, a can body of a two-piece aluminum can, that is, a DI can body or a can lid material. In particular, the present invention relates to a method for producing an Al-Cu-Mg-Mn-based aluminum alloy hard plate that has little ears during molding and is excellent in strength and moldability.

2. Description of the Related Art Conventionally, aluminum alloy sheets for forming, especially aluminum alloy sheets used as can bodies for DI cans, have recently been made thinner and have a higher thickness in order to expect economic effects by using thinner sheets with higher strength. Strengthening is in progress. Various aluminum alloys have been conventionally used for this type of application, but in particular, JIS 3004 alloy hard plate, which is an Al-Mg-Mn alloy, is cold-rolled at a high rolling rate to increase strength. It is often used for the can body of DI cans because it shows relatively good moldability even when it is used.

As a method for manufacturing this 3004 alloy hard plate, after subjecting the ingot to homogenization heat treatment, hot rolling is performed according to a conventional method,
Then, after cold rolling or without cold rolling, intermediate annealing is often performed, and then final cold rolling is performed to obtain a product sheet. 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.

Problems to be Solved by the Invention In addition to having high strength and excellent moldability as described above, the performance required for the body of a DI can is
It is important that the ear rate during DI processing is low.

By the way, the problems of the conventional method for manufacturing the hard plate of 3004 alloy as described above are different between the case where the intermediate annealing is performed in the box-type annealing furnace and the case where the intermediate annealing is performed in the continuous annealing furnace.

That is, first, in the process using the continuous annealing furnace, it is difficult to control the ear rate generated during DI processing, and some devise is required in the process until the intermediate annealing.

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 becomes difficult to control the earring rate.

The present invention has been made in view of the above circumstances, and an aluminum alloy hard plate which is easy to control the ear rate at the time of forming even if the final cold rolling rate is increased, and has excellent formability and strength. It is intended to provide a manufacturing method.

Means for Solving the Problems In the method of the present invention, basically, the component composition of an Al-Mg-Mn-Cu-based aluminum alloy is appropriately set, and in hot rolling, B) other strains of the matrix are accumulated without being recovered, and re-crystallized around the intermetallic compound as a starting point during self-heating after hot rolling or recrystallization by subsequent recrystallization annealing. While preventing crystallization / sub-crystallization, it promotes re-crystallization / sub-crystallization starting from the other matrix to facilitate control of the ear rate.

Specifically, the manufacturing method of the aluminum alloy hard plate for molding of the present invention, Mg0.5 ~ 2.5wt%, Cu0.1 ~ 1.0wt%,
An alloy containing Mn 0.6 to 1.8 wt%, Si 0.1 to 1.0 wt%, Fe 0.2 to 1.0 wt%, Fe / Si weight ratio of 3.0 or less, and the balance Al and unavoidable impurities. After performing the homogenizing heat treatment on the ingot and hot rolling,
The total rolling reduction in hot rolling shall be 70% or more, and at least between the rolling passes in the rolling process of the rolling reduction between 70% before the hot rolling, the re-generation generated during each rolling pass. The area ratio of crystal grains is controlled to be 10% or less, and the hot rolling temperature is set to a temperature within the range of 270 to 350 ° C, and the hot rolling sheet thickness is set to 3 mm or less. By promoting recrystallization by self-heating, recrystallized grains are generated in the microstructure of the cross section of the hot-rolled sheet.
The total area ratio occupied by subgrains with a grain size of 10 μm or less
After obtaining a hot-rolled sheet of 50% or more, (A) no treatment (however, this treatment is limited to 100% recrystallization due to self-heating of the hot-rolled sheet after hot rolling), (B) Recrystallization treatment (C) After cold rolling with a rolling reduction of 30% or less, recrystallization treatment, through any of the above processes (A), (B), and (C), and then 50% or more It is characterized by performing cold rolling.

In addition, here, the case where there is no treatment between the hot rolling and the final cold rolling of 50% or more (case (A)) is defined in claim 1, and recrystallization treatment as in (B) is performed. The case of carrying out cold rolling is defined in claim 2, and the case of performing cold rolling and recrystallization treatment at 30% or less as in (C) is defined in claim 3.

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 → βMg
_It follows the precipitation process such as 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 solid solution strengthening by itself. As described above, Mg is an essential element for improving the strength. However, if the Mg content is less than 0.5 wt%, the strength improving effect is small. On the other hand, if the Mg content exceeds 2.5 wt%, there is no particular problem in drawing forming.
Since it becomes easy to work and harden, it deteriorates moldability such as redrawability and ironing workability. Therefore, the amount of Mg is 0.5-2.5wt%
Within the range of.

Cu: In the method of the present invention, if the solid solution amount of Cu can be maintained at the time of hot rolling, solution treatment of Cu can be expected even in a process using a box-type annealing furnace, and, of course, a continuous annealing furnace is used. This effect can be expected in the process used. Therefore, if Cu is added, Al-Cu-Mg during the paint baking process
The strength can be improved by utilizing age hardening in the precipitation process of the system precipitate. However, if the Cu content is less than 0.1 wt%, the above effects can hardly be expected.On the other hand, if Cu is added over 1.0 wt%, age hardening can be easily obtained, but work hardening tends to occur during molding. As a result, the formability is impaired, and the addition amount of Cu is set to 0.1 to 1.0 wt%.

Mn: Mn is an element that contributes to the improvement of strength and is effective in improving the formability. Particularly in the can body material, which is the main application of the present invention, since severe ironing is performed, addition of Mn is important for improving the moldability. Normally, an emulsion type lubricant is used in the ironing of aluminum alloy sheets, but when there are few Mn-based crystallized substances,
Even if the emulsion-type lubricant has the same strength, the emulsion-type lubricant has insufficient lubricity, and there is a possibility that appearance defects such as scratches and seizures called "goring" may occur. The Mn-based crystallized product has a solid lubricating effect during ironing,
Although it is effective in preventing the occurrence of appearance defects after ironing, the effect is affected by the size, amount, and type of crystallized substances. When casting with a fast cooling rate using the continuous casting method, not only Mn content of more than 1.8 wt% can be cast without any problems, but also the crystallized substance size can be adjusted by subsequent heat treatment. However, in the DC casting method, which is currently the mainstream, if Mn is added in excess of 1.8 wt%, primary crystal giant intermetallic compound of MnAl ₆ may be formed, and conversely, the formability may be significantly impaired. Therefore, the upper limit of the amount of Mn added is set to 1.8 wt%. If the Mn content is less than 0.6 wt%, the above-mentioned solid lubricating effect of the Mn compound cannot be obtained, so the lower limit of the Mn content is 0.
It was 6 wt%.

Fe: Fe is an element necessary for promoting the crystallization and precipitation of Mn together with Si, and controlling the solid solution amount in the aluminum matrix and the dispersed state of the Mn-based insoluble compound. In particular, in the case of the method of the present invention, the aim is to obtain the optimum directionality for controlling the ear rate during molding, but in order to obtain this effect, the intermediate annealing (recrystallization treatment) Of solid solution, dispersion state of insoluble compound and work strain after hot rolling (or hot rolling stage and subsequent mild cold rolling) to obtain the optimum recrystallization structure according to the heat history of It is necessary that processing strain) exist before recrystallization.
In order to obtain such conditions, it is necessary to make the Fe amount and Si amount appropriate to the added amount of Mn. If the Fe content is less than 0.2 wt%, it will be difficult to obtain an appropriate compound dispersion state. On the other hand, if the Fe content exceeds 1.0 wt%, the primary crystal giant intermetallic compound will be generated in combination with Mn addition to form There is a risk of serious loss of sex. Therefore, the Fe content is set within the range of 0.2 to 1.0 wt%.

Si: It is well known that age hardening can be expected even in the precipitation process of Mg ₂ Si-based compound when Si is added, but the role of Si in the present invention is not the improvement of strength but the direction of molding. It is in sex control. 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 during molding. 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. If the Fe / Si ratio is 3.0 or less, the solid solution amount of Fe can be reduced and the directionality can be improved. Therefore, the Si content needs to be determined so that the Fe / Si ratio is 3.0 or less according to the Fe content. Further, if the absolute amount of Si is less than 0.1 wt%, it is difficult to obtain the optimum Fe / Si ratio, while if it exceeds 1.0 wt%, the effect of promoting the precipitation of Fe is saturated, and an excessive solid solution state results in aging. Although the curability is high, it is not suitable for controlling the direction. Therefore, the absolute amount of Si is 0.1 to 1.0 wt.
Within the range of%.

The balance of the above components may basically be Al and inevitable impurities. In addition, in a usual aluminum alloy, a small amount of Ti or Ti and B may be added for refining the ingot crystal grains. Even in the case of the present invention, a small amount of Ti or Ti and B is contained. Is also good. However, when Ti is added, 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. When B is added together with Ti, if B is less than 1 ppm, the effect of B is not obtained, while if B exceeds 500 ppm, coarse particles of TiB ₂ are mixed and impair the formability, so that B is 1 to 500 ppm. It is preferably within the range. In addition, Be is used to prevent molten metal oxidation during casting.
May be added in the range of 0.02 wt% or less. In addition, trace elements such as Cr, Zn, V, and Zr may be contained as impurities, and if Cr 0.3 wt% or less, Zn 0.1 wt% or less, V 0.3 wt% or less, Zr 0.3 wt% or less The effect of the invention is not 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 melted and cast according to a conventional method. As a casting method, a general DC casting method (semi-continuous casting method) may be applied.
The obtained ingot is subjected to heating as a homogenizing heat treatment and then preheating before hot rolling, or preheating before hot rolling which also serves as a homogenizing heat treatment, and then hot rolling. Roll it. The conditions of 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, it is important to control the recrystallization behavior. Therefore, before explaining the control of the recrystallization behavior in the method of the present invention, the general recrystallization behavior in the case where the aluminum alloy is subjected to hot working (and further subjected to recrystallization treatment if necessary) is explained in advance. To do.

As is widely known, dislocations are increased / accumulated by work hardening in the initial stage of hot working of an aluminum alloy, and as the dislocations increase, dislocation movement and slip are activated and the dislocation disappearance rate increases. It will match the generation speed,
The dislocation density will reach an equilibrium value. In the process, rearrangement of dislocations, that is, polygonization occurs, and a fine network structure (sub-grain structure) divided by sub-grain 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 the 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 structure.

And in the case of the method of the present invention, the total reduction rate in hot rolling is 70% or more, and at least the recrystallization rate between each rolling pass in the rolling process of the reduction rate of 70% before hot rolling (each The area ratio of recrystallized grains generated between rolling passes is controlled to be 10% or less for each rolling pass.
That is, when the reduction ratio of the finish rolling of the hot rolling is 70% or more, the recrystallization ratio between the passes during the rolling of the reduction ratio of at least 70% can be traced back to 10% or less before the completion of rolling in the finish rolling. If the finish rolling is less than 70%,
Through the finish rolling and the preceding intermediate rolling or rough rolling, the rolling reduction is at least 70 before the end of rolling.
It may be controlled so that the recrystallization rate between each pass in the range of 10% is 10% or less. Specifically, for example, if the hot rolled plate thickness is 3 mm, the rolling reduction from the stage of the plate thickness of 10 mm to the finish of 3 mm is 70%,
It may be controlled so that the recrystallization rate in each pass in several passes from the stage of at least 10 mm in the hot rolling process to the end of hot rolling becomes 10% or less.

In this way, it is necessary to restrict the recrystallization rate between each pass in the rolling process at the rolling rate of 70% or more before the completion of rolling in the hot rolling to 10% or less, respectively. B) Other strains of the matrix accumulate without recovering, and when recrystallized by self-heating after hot rolling or by recrystallization annealing after that, recrystallization / subcrystallization starting from around the intermetallic compound is performed. On the other hand, it means to promote recrystallization / subcrystallization starting from the other matrix while preventing the above. That is, in this invention, the ear ratio of the final plate is controlled by increasing the recrystallization / subcrystal of the cube orientation before the final cold rolling after the end of hot rolling, but the cube orientation starts from the intermetallic compound periphery. This is because the recrystallization / sub-crystals that have the following formulas have almost no cube orientation, and conversely, the re-crystals / sub-crystals having the other matrix as the starting point have many cube orientations. Controlling the recrystallization rate between each pass in this way can be achieved by appropriately adjusting the time (holding time) between each pass according to the rolling temperature and the rolling reduction. For example, in Fig. 1, for a typical 3004 alloy as a can body, with respect to the rolling temperature and the rolling reduction in one pass of hot rolling,
The isochronous line of the holding time after the rolling pass is shown so that the recrystallization rate is 10%. In Fig. 1, the lower left region of each isochronous line is the region with a recrystallization rate of 10% or less. Therefore, from the rolling temperature and the rolling reduction, the retention time between passes that reduces the recrystallization rate to 10% or less You can ask for a guide. Note that
If the amount of alloying elements such as Mg is higher than that of 3004 alloy, the isochronous line in Fig. 1 shifts to the low pressure side and low temperature side, and the isochronous line also deviates due to the heat history before finish hot rolling. The conditions on the side can be easily found from this figure.

Furthermore, the rising temperature in hot rolling is within the range of 270 to 350 ° C, the rising sheet thickness is 3 mm or less, and the hot rolled sheet after hot rolling remains as it is, and the microstructure of the hot rolled sheet has recrystallized grains and The recrystallized state is adjusted so that the total area ratio occupied by sub-crystal grains of 10 μm or less is 50% or more. Such conditions are important not only for controlling the recrystallization rate between each pass in the rolling process with a rolling reduction of 70% or more before the end of hot rolling as described above, but also for controlling the ear rate during forming. is there.

That is, by controlling the recrystallization rate between each pass as described above, a) the strain around the intermetallic compound is recovered, and b) the strain of the other matrix is accumulated without being recovered, and after hot rolling. Prevents recrystallization / subcrystallization starting from the vicinity of the intermetallic compound when recrystallizing by self-heating or subsequent recrystallization annealing, while promoting recrystallization / subcrystallization starting from other matrix Of. As a result, recrystallization of the cube orientation after the hot rolling and before the final cold rolling
The sub-crystals are increased, resulting in a 0-90 ° high-eared plate as the final plate. That is, a final plate having a low 45 ° ear and a low ear rate as a whole can be obtained.

If the total area ratio of recrystallized grains and subgrains of 10 μm or less does not reach 50% or more with the heat rolling, the subsequent recrystallization annealing or recrystallization by self-heating may be performed. 0-90 ° Higher ear tissue cannot be obtained. And again like this, the recrystallized grains and 10 μm
The hot rolling temperature must be 270 ° C. or higher in order to bring the total area ratio of the following sub-crystal grains to 50% or higher. That is, when the hot rolling temperature is less than 270 ° C,
No matter what finish rolling conditions are applied, the total area ratio of recrystallized grains and subcrystalline grains does not exceed 50% after hot rolling. On the other hand, if the hot rolling temperature exceeds 350 ° C, the roll coating during hot rolling becomes too strong to be practical, and the recrystallization rate between each pass is 10% in the rolling process with a rolling reduction of 70% before the end of hot rolling. It becomes difficult to suppress the following. Therefore, the hot rolling temperature is set within the range of 270 to 350 ° C. If the hot rolling temperature is in the range of 270 to 350 ° C, a plate with a high ear of 0-90 ° can be obtained after complete recrystallization, but uniform and fine recrystallization in the longitudinal direction and width direction of the hot rolled plate. Considering the ease of rolling conditions and obtaining grains, 270 to 3
Even within the range of 50 ° C., the range of 280 to 310 ° C. is particularly preferable. Further, if the hot rolled sheet thickness exceeds 3 mm, the uniformity after recrystallization is lost, and the ear ratio does not become a high ear of 0-90 °. Therefore, the hot rolled sheet thickness is set to 3 mm or less.

The hot-rolled sheet thus obtained is subjected to recrystallization treatment immediately after cooling or immediately as it is for complete recrystallization. Alternatively, the coil after hot rolling is completely recrystallized by the self heat of the hot rolled plate coil. Alternatively, cold rolling under a light reduction with a rolling reduction of 30% or less is performed, and then recrystallization treatment is performed for complete recrystallization.

That is, after hot rolling, the hot rolled coil undergoes at least some recrystallization due to its own heat, but when 100% recrystallized due to this self held heat, it is not actively recrystallized. In other cases, that is, in the case where 100% recrystallization cannot be achieved due to the self-held heat of the hot-rolled coil, the recrystallization treatment is positively performed for complete recrystallization. This recrystallization treatment may be performed on the hot-rolled sheet, or may be performed after cold rolling at a light pressure of 30% or less. Here, the reason why the recrystallization treatment may be performed after cold rolling at 30% or less after hot rolling is as follows. That is, in the cold rolling of low workability of 30% or less, the grains of the cube orientation generated by hot rolling do not cause rotation of the orientation, and can serve as recrystallization nuclei in the subsequent recrystallization treatment, Therefore, it is possible to finally obtain a 0-90 ° high-eared sheet even if recrystallization treatment is performed after light cold rolling at 30% or less. 100% due to the heat of the hot rolled coil
Even when recrystallized, the recrystallization treatment may be performed subsequently or after cold rolling under a light pressure of 30% or less.

Such recrystallization treatment may be carried out under the condition that 100% recrystallization is essential, and may be either batch type heat treatment using a box furnace or continuous heat treatment using a continuous furnace. In the case of batch type heat treatment, it is usually sufficient to hold at 300 to 400 ° C for 0.5 to 10 hours, and in the case of heat treatment using a continuous furnace,
Usually, heating to 380 to 620 ° C. may be performed without holding or for holding for 2 minutes or less.

After completely recrystallizing as described above, the rolling reduction is 50%.
The above cold rolling may be performed to obtain a hard plate of the product. In addition, when the formability in deep drawing or forming that requires local elongation is important, after cold rolling at 50% or more as described above, the final finish is performed at a temperature in the range of 90 to 250 ° C. It may be annealed.

The hard plate thus obtained is a material having a low ear rate and high strength during molding. In addition, when used for applications such as can materials where baking is performed, sufficient strength can be obtained after the baking treatment.
Especially when the final annealing is performed at 90 to 250 ° C. after cold rolling, the strength after coating and baking can be further increased by selecting an annealing method having a solutionizing effect.

The recrystallization ratio (area ratio of recrystallized grains in the cross section) can be determined by observing the structure of the cross section with an optical microscope or the like, and the area ratio occupied by subcrystalline grains of 10 μm or less (subcrystal ratio) ) Can be determined by similarly observing the microstructure state of the cross section with a transmission electron microscope or the like. Therefore, in carrying out the method of the present invention, hot rolling or the like is performed under various conditions in advance to perform the steps. It is only necessary to determine the recrystallization rate or the sub-crystallization rate as described above and obtain the optimum conditions according to the alloy component composition and the like.

EXAMPLE Alloys within the composition range of the present invention components shown in alloy numbers No. 1 and No. 2 in Table 1 and alloys outside the composition range of the present invention component shown in alloy number No. 3 in Table 1 (comparative alloy ) And No. 1 and No. 2 with respect to the ingots obtained by DC casting according to a conventional method.
In the case of alloy No.3, the ingot is heated at 600 ℃ for 6 hours,
In the case of the alloy No. 1, the ingot is heated at 500 ° C. for 2 hours, and then hot rolling is performed.
As shown in I, the plate thickness is 2.0 to 3.5 at the rising temperature of 260 to 320 ℃.
finished to mm. At this time, in several passes before the end of hot rolling, the recrystallization rate between the passes was 10% or less, but the reduction ratio from the recrystallization rate of 10% or less to the end of hot rolling was Shown in the table. Further, the total of recrystallized grains in the microstructure at the hot rolling stage and recrystallized grains of 10 μm or less was investigated, and the results are also shown in Table 2.

After that, the hot-rolled sheet was subjected to intermediate annealing using a continuous furnace or intermediate annealing using a box furnace as a recrystallization treatment after the thickness was kept as it was or after cold rolling to obtain an intermediate sheet thickness. . Table 2 shows the sheet thickness at the time of performing the recrystallization treatment (intermediate annealing), the annealing method, and the annealing conditions (temperature, time). After that, cold rolling was further performed to give a final plate thickness of 0.30 mm as shown in Table 2. Of the hard plates with the final thickness obtained, some of them were subjected to final annealing at 160 ° C x 2 hours or 120 ° C x 2 hours as shown in Table 2, while others were final. It was directly subjected to the next test without being annealed.

For each plate obtained as described above, as a treatment equivalent to coating baking, baking was performed at 270 ° C. for 20 seconds or 200 ° C. for 20 minutes, the yield strength after baking was examined, and further the directionality after baking, The ear rate was examined as follows. That is, blank diameter 58mmφ, punch diameter 32mm
Under conditions of φ and clearance of 45%, deep drawing was performed without ironing and the characteristics of the material were easily revealed, and the ear ratio after deep drawing was examined. The results are shown in Table 3.

Further, as the evaluation of the formability after baking, among the plates, the plates obtained by the manufacturing process codes A and I were examined for deep draw formability, bendability, and Erichsen value. Further, with respect to the plates obtained by the manufacturing process codes B to H, deep drawability and ironing formability were examined as formability evaluation assuming a can body. The results are shown in Table 3. For these evaluations, the manufacturing process code A,
The plate obtained by I was subjected to relative evaluation using a plate obtained by the process I corresponding to the conventional example as a reference (good: ◯), and the plates obtained by the manufacturing process codes B to H were also compared to the conventional example. Relative evaluation was carried out using a plate produced by the corresponding H process as a reference (good: ◯).

Among the manufacturing processes A to I shown in Table 2, C of Comparative Example
Has a low hot rolling temperature, so recrystallized grains during hot rolling +
The sub-crystal grains are 0%. In Comparative Example D, the hot-rolled sheet thickness exceeds 3 mm, and the recrystallization treatment is performed after the hot-rolled sheet has been cold-rolled over 30%. Further, in Comparative Example F, the hot rolling temperature was low, and the recrystallized grains + the subcrystalline grains in the hot rolling were 0%. Further, G of the comparative example has a recrystallization rate of 10 between each pass.
The reduction ratio before hot rolling after 70% or less was less than 70%. Further, in the conventional example, H is obtained by performing recrystallization treatment (intermediate annealing) after cold rolling at a rolling reduction of more than 30% after hot rolling. In the conventional example I, the alloy composition of the material is out of the range specified by the present invention.

As is clear from Table 3, the aluminum alloy hard plate (manufacturing process code) obtained according to the conditions of the present invention.
A, B, E) are superior in the directionality compared with the hard plates obtained by the conventional example or the comparative example, and have the same or higher performance in terms of strength and formability. It was Therefore, according to the method of the present invention, it is apparent that high strength equal to or higher than conventional ones and excellent moldability can be provided without increasing the ear rate.

EFFECTS OF THE INVENTION According to the method for producing a forming aluminum alloy hard plate of the present invention, as a hard plate used as a can body material or the like,
It is possible to obtain a plate that has less ears during molding and is excellent in strength and moldability. In particular, in the method of the present invention, even if the strength is increased by a combination of increasing the reduction ratio of cold rolling and applying continuous annealing as an intermediate annealing (recrystallization treatment) method, the increase in ear ratio is small. ,
It is possible to obtain a hard plate having excellent strength and ear ratio. Although the method of the present invention is suitable for the production of can body materials, the strength of 5182 alloy, which has been conventionally used as a can lid material, can be achieved without increasing the ear rate. Also suitable for manufacturing hard plates for lid materials,
In addition, it can be applied to the production of hard plates for molding for various purposes.

[Brief description of drawings]

FIG. 1 is a diagram showing an isochronous line of rolling holding time such that the recrystallization rate is 10% with respect to the rolling temperature and the rolling reduction during one-pass rolling for the 3004 alloy.

Claims (3)

[Claims] 1. Mg 0.5 to 2.5 wt%, Cu 0.1 to 1.0 wt%, Mn 0.6
~ 1.8wt%, Si0.1-1.0wt%, Fe0.2-1.0wt%, Fe / Si weight ratio is 3.0 or less, and the balance is Al and unavoidable impurities. After subjecting the ingot to homogenization heat treatment and then performing hot rolling, the total rolling reduction in hot rolling should be 70% or more, and at least the rolling reduction between 70% before hot rolling Between each rolling pass in the rolling process, the area ratio of the recrystallized grains generated between each rolling pass is controlled to be 10% or less, and the hot rolling temperature is within the range of 270 to 350 ° C. With the temperature of and the hot rolled plate thickness of 3 mm or less, by proceeding with recrystallization by self-heat after hot rolling,
Obtained a hot-rolled sheet in which the area ratio of recrystallized grains in the microstructure of the cross section of the hot-rolled sheet was 100%, and then 50%
A method of manufacturing an aluminum alloy hard plate for forming, which has a small earring rate, characterized by performing the above cold rolling. 2. Mg 0.5 to 2.5 wt%, Cu 0.1 to 1.0 wt%, Mn 0.6
~ 1.8wt%, Si0.1-1.0wt%, Fe0.2-1.0wt%, Fe / Si weight ratio is 3.0 or less, and the balance is Al and unavoidable impurities. After subjecting the ingot to homogenization heat treatment and then performing hot rolling, the total rolling reduction in hot rolling should be 70% or more, and at least the rolling reduction between 70% before hot rolling Between each rolling pass in the rolling process, the area ratio of the recrystallized grains generated between each rolling pass is controlled to be 10% or less, and the hot rolling temperature is within the range of 270 to 350 ° C. And the hot rolled sheet thickness is 3 mm or less and the area ratio occupied by recrystallized grains and subcrystalline grains with a grain size of 10 μm or less is 50% or more in total in the microstructure of the cross section of the hot rolled plate Obtain a hot-rolled sheet, and then recrystallize it for another 50
% Or more of cold rolling is performed, and a method for producing an aluminum alloy hard plate for forming, which has a small ear rate, for forming. 3. Mg 0.5 to 2.5 wt%, Cu 0.1 to 1.0 wt%, Mn 0.6
~ 1.8wt%, Si0.1-1.0wt%, Fe0.2-1.0wt%, Fe / Si weight ratio is 3.0 or less, and the balance is Al and unavoidable impurities. After subjecting the ingot to homogenization heat treatment and then performing hot rolling, the total rolling reduction in hot rolling should be 70% or more, and at least the rolling reduction between 70% before hot rolling Between each rolling pass in the rolling process, the area ratio of the recrystallized grains generated between each rolling pass is controlled to be 10% or less, and the hot rolling temperature is within the range of 270 to 350 ° C. And the hot rolled sheet thickness is 3 mm or less and the area ratio occupied by recrystallized grains and subcrystalline grains with a grain size of 10 μm or less is 50% or more in total in the microstructure of the cross section of the hot rolled plate After obtaining a hot-rolled sheet, cold rolling with a rolling reduction of 30% or less, recrystallization treatment, and then 50 Method for producing a small molding aluminum alloy hard plate ears index, characterized in that performing the above cold rolling.