JP2002212691A - Method for producing aluminum alloy sheet material for can body having excellent barrel cutting resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an aluminum alloy sheet material which has excellent barrel cutting resistance. SOLUTION: An aluminum alloy ingot is subjected to homogenizing treatment. In a hot rolling stage, the temperature of a coil after the hot rolling is controlled to 400 to 500 deg.C, and the recrystallization rate of the coil is controlled to 70 to 100%. The coil is cold-rolled, and is annealed in a first process annealing stage. The coil is cold-rolled at a draft in the range of 10 to 25% in a second cold rolling stage, and is annealed in a second process annealing stage. In a final cold rolling stage, cold rolling is performed for one pass so that the draft is controlled in the range of 45 to 70%, and the temperature of the coil on coiling after the cold rolling is controlled to 90 to 140 deg.C. After the completion of the coiling, the coil is held to <90 deg.C for 1 to 10 hr.

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 an aluminum alloy sheet for a can body having excellent resistance to body breakage.

[0002]

2. Description of the Related Art With an increase in demand for canned beverages and the like, recently, so-called DI (Deep drawing & Ironing) cans made of an aluminum-based alloy suitable for the containers have been mass-produced. This DI made of aluminum base alloy
As a general manufacturing method of the main body of the can, an aluminum-based alloy plate is deep-drawn in multiple steps, further ironed to form the can main body, and after baking coating, neck processing and the like are performed. The aluminum-based alloy plate used here is required to have both sufficient strength after can making and formability to withstand multi-stage deep drawing, ironing, necking, and the like.

In general, as an aluminum-based alloy for deep drawing, an Al-Mn-Mg-based alloy such as the American Aluminum Association Standard (AA) 3004 alloy is widely used. In order to manufacture an aluminum-based alloy plate for deep drawing from this alloy, (a) first, an ingot of this alloy is hot-rolled,
Next, (b) cold rolling is performed to obtain a sheet having an appropriate thickness. The sheet after the cold rolling is subjected to (c) intermediate annealing, and further (d) hardening by cold rolling according to required strength. Processing is performed.

[0004] In the production process of the aluminum-base alloy sheet for deep drawing, in order to improve the strength of the sheet material, it is necessary to increase the cold rolling ratio in the cold rolling (d). However, when the degree of cold rolling is increased, a so-called rolling texture develops, and anisotropy appears remarkably during plastic deformation, and the top of the can body formed according to the rolling direction of the sheet material when deep drawing is performed. A phenomenon occurs in which the height of the edge changes in a valley-like manner. This part that has been deformed into a mountain valley is usually
They are called "ears". The can body after deep drawing is then ironed, and then trimmed to cut the opening horizontally to make the can height uniform in order to attach a lid member.
Ears are also removed during this trimming process, so if the height of the ears is high, the amount of plate material to be removed (hereinafter referred to as "ear ratio") increases, the yield decreases, and the manufacturing cost increases. There was a problem of doing. Therefore, a plate material having a low ear ratio is required.

In general, when an aluminum-based alloy sheet is cold-rolled, a rolled texture having peaks (hereinafter, abbreviated as 45 ° ears) in the direction of 45 to 60 ° with respect to the rolling direction tends to develop. is there. Therefore, in order to reduce the ear ratio, it is necessary to suppress the development of the rolling texture. It has been found that this can be achieved by controlling the state of formation of the recrystallized texture in the sheet material before cold rolling. That is, a method of developing a recrystallized texture called “cubic orientation” that generally produces a deep drawing ear in the direction of 0-90 ° before cold rolling is used. The development of the cubic orientation gives rise to ears in the 0-90 ° direction, but the subsequent cold rolling does not develop the ears in this direction much, while the development of the rolled texture to produce the 45 ° ears also occurs. It is suppressed, and as a result, the peak of the ear at the periphery of the opening is made uniform. By this method, the degree of rolling 80
%, After low-temperature cold rolling, a low-ear plate material in which a few 0-90 ° ears and 45 ° ears coexist is obtained.

As a specific method of developing the recrystallized texture of the cubic orientation, various conditions during hot rolling are adjusted, and the coil wound after hot rolling is cooled until the coil is cooled, or is wound. There is known a method of controlling recrystallization generated when annealing a coil taken (Japanese Patent Laid-Open No. 5-125500). In this method, the cold rolling of (d) is performed on the recrystallized hot rolled sheet without performing the cold rolling of (b) or the cold rolling of (b) and the intermediate annealing of (c). Apply. At present, the thickness of the plate material mainly used for DI cans is about 0.3 mm, so if this method is applied and the final cold rolling reduction is 80 to 90%,
It is necessary to perform hot rolling so that the thickness becomes 1.5 to 3 mm. Therefore, usually, after rolling using a reverse type hot rolling mill, further rolling using a tandem type finishing hot rolling mill or a reverse type hot finishing mill equipped with coil winding devices on both sides of the rolling mill. Is used. However, these hot finishing mills are large-scale and expensive, and use of these hot rolls imposes a heavy burden on production costs. Furthermore, as the thickness of the material for cans becomes thinner, the effect of the temperature drop between the rolling rolls and passes increases, and it is necessary to further increase the equipment capacity in order to maintain appropriate hot rolling conditions. Tended to increase.

Therefore, a method of using only a single-mill reverse hot rough rolling mill in all the steps of hot rolling was studied. However, when attempting to produce thin-walled sheet material using this rough rolling mill, the temperature drop between passes is remarkable, and it is extremely difficult to maintain hot rolling conditions for controlling recrystallization of a hot-rolled sheet. Become. As a means for solving this problem, an element that imparts age hardening to the aluminum-based alloy is added, and after the cold rolling of the above (b), the intermediate annealing of the above (c) is performed at a relatively high temperature to form a solution, A method has been proposed in which sufficient strength can be obtained even if the rolling degree of the cold rolling in the above (d) is reduced (Japanese Patent Publication No. 60-35424).

According to this method, precipitation hardening is performed by heating the baking coating after the DI can body is formed, so that softening due to heating during baking is suppressed, and sufficient strength is obtained even if the cold rolling reduction is reduced. Can now be obtained. Therefore, even if the cubic texture is not sufficiently developed after the intermediate annealing in the above (c), the rolling reduction of the cold rolling can be reduced, so that the development of the rolled texture becomes light and the ear ratio is relatively low. DI cans are now available. This method has a slightly higher ear ratio than when a finishing hot rolling mill is used, and therefore has a larger trim amount, but can be applied without using a finishing hot rolling mill, which requires expensive equipment costs. The result is an advantageous method.

However, recently, demands for reducing the diameter of the lid member of the DI can have increased due to economical and design requirements, which has led to an increase in the diameter reduction rate of the neck portion of the can body material. However, when the diameter reduction ratio of the neck portion is increased, the height of the can is changed at the opening due to the anisotropy of the material in the forming process of the neck portion as in the case of the deep drawing forming. Problems have arisen. The height variation of the opening caused by the neck forming is hereinafter referred to as “neck ear”. The opening of the can body is flanged after the neck is formed, and this flange is used for tightening with the lid member.If the neck ear is large, the flange width differs depending on the direction or the shape of the neck part However, there arises a problem that the shape varies depending on the direction, so that the processing steps are complicated and there is a possibility that an adverse effect may appear on the appearance. Therefore,
There has been a demand for an aluminum-based alloy plate for deep drawing which hardly causes a neck ear even when the diameter reduction ratio during neck forming is increased.

[0010] From such a background, the present inventors have disclosed Japanese Patent Application Laid-Open No. Hei 10-330898 (Japanese Patent Application No. 9-142791).
A patent application has been filed for a method for producing an aluminum alloy sheet for deep drawing using a single-mill reverse-type hot rolling mill for both rough rolling and finish rolling, which hardly causes neck ears during deep drawing or neck forming. According to the technology according to this patent application, a soaking step, a hot rolling step, a first cold rolling step, a first intermediate annealing step, a second cold rolling step, a second intermediate annealing step, and a third intermediate annealing step And the final cold rolling step in order to produce an aluminum-based alloy sheet, in particular, the hot rolling end temperature is in the range of 280 to 350 ° C., and then the first cold rolling of 60 to 90% is performed. Alms, 25
It was required to perform the first intermediate annealing for 2 to 24 hours in a temperature range of 0 to 280 ° C.

[0011]

The hot rolling end temperature is set to 280 to 350 ° C. in order to prevent recrystallization after hot rolling, Cracks are likely to occur on both sides of the aluminum-based alloy plate in the process of performing cold rolling with high work hardening and a high rolling rate of 60% or more, and it is necessary to trim both sides to remove cracks. There was a problem that the yield was reduced. Therefore, the present inventors reviewed the above-described manufacturing conditions to increase the hot end temperature from 280 to 280.
Even when the temperature is higher than the range of 350 ° C., a production condition in which ears are hardly formed during deep drawing or neck molding is found, and therefore, a condition in which the occurrence of cracks in the first cold rolling is suppressed is found. 2000-26946 (Japanese Patent Application No. 10-
197867) or Japanese Patent Application Laid-Open No. 2000-26945 (Japanese Patent Application No. 10-197866).

The above-mentioned first intermediate annealing is a process for annealing the coil, which has been hardened by the first cold rolling process, to a semi-softened state. The ear ratio depends on the degree of softening. In order to reduce the variation in ear ratio, it is necessary to strictly control the heating temperature and time.Therefore, research was conducted on manufacturing conditions that could ease the control of the heating temperature and time, and the results were determined. JP 2
000-26946 or JP-A-2000-2694
A patent application was filed as No. 5. Further, the first intermediate annealing is usually performed in an annealing furnace called a batch type. Here, an aluminum-based alloy plate is wound in a coil shape, and is carried into a furnace in a coil state to perform annealing. Since the heating rate differs depending on the width and conditions of the coil, that is, if the coil weight is different, the temperature cannot be controlled uniformly, so that the same heating temperature and time are required for the furnace according to the dimensions of the coil. It was necessary to change the operating conditions, and there was a problem that the dimensional control of the coil was complicated. That is, when a large number of coils are simultaneously loaded into the same furnace for processing, there is a problem that heating and cooling conditions differ for each coil having a different size. Therefore, it is necessary to make the dimensions of all coils the same. Was.

[0013] For this reason, it is necessary to separately perform annealing according to the dimensions of the coil to be manufactured, and there is a problem that the inventory of intermediate products increases due to adjustment of the production time. Japanese Patent Laid-Open Publication 2000
-26946 and JP-A-2000-26945. The technology provided in these patent applications has made it possible to solve the aforementioned problems such as ear ratios, but the application of the aluminum alloy plate material obtained by the technology according to the aforementioned patent application to DI cans Was examined in more detail, and it was found that when ironing was performed, there was a tendency that a problem of cut-out easily occurred.

That is, according to the study of the present inventors, in the relationship between the manufacturing process of the aluminum alloy material and the breakage resistance, as the strength of the aluminum alloy material increases, the cutout tends to occur easily. Even if aluminum alloy material strength or can strength after can making is the same,
The higher the final cold rolling rate of the aluminum alloy material,
It was concluded that the cut-out resistance deteriorated. In addition, although the aluminum alloy material is heated by the heat generated during the final cold rolling and the material temperature rises, if the temperature of the aluminum alloy material coil wound after the final cold rolling is too high, the body breakage resistance is significantly deteriorated. It turned out to be. Furthermore, it is generally thought that there is no direct correlation between the anisotropy of aluminum alloy material and cut-out resistance. It is easy to think that the broken pieces may cause a body cut or a bottom crack.

Recently, a method of manufacturing a can body using a laminated material obtained by pre-coating a resin film of polyethylene terephthalate or the like on an aluminum alloy plate material has been used in some cases. In this case, the surface is formed into a satin shape by molding. However, since there is a problem that it is difficult to obtain a uniform satin-like surface, a uniform and fine grain structure is desired as an aluminum alloy material. From the above background, the present inventors have obtained an aluminum alloy material for a seed can body having uniform and fine crystal grains, a low final cold rolling reduction, and low anisotropy. As a result of studying a manufacturing method which is excellent in cut-out resistance and also conducting a study combining problems such as bottom wrinkling of an aluminum can, the present invention has been achieved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to manufacture a material having a high material strength without lowering the yield, and to have excellent cut-out resistance. A uniform satin-like surface can be obtained, anisotropy is reduced, and the ear ratio can be reduced.
An object of the present invention is to provide a method for producing an aluminum alloy sheet for a can body having excellent body breakage resistance, which can also solve the problem of bottom wrinkling.

[0017]

In order to solve the above-mentioned problems, the present invention provides a method for producing Mg: 0.9 to 1.7% by weight and Mn: 0.1% by weight.
8 to 1.2% by weight, Fe: 0.30 to 0.55% by weight, S
i: 0.25 to 0.45 wt%, Cu: 0.20 to 0.4 wt%, Zn: 0.05 to 0.4 wt%, Ti: 0.02 to
An aluminum alloy containing 0.2% by weight, with the balance being an inevitable impurity and Al, is melted, and the ingot obtained by semi-continuous casting is subjected to hot rolling and cold rolling to produce an aluminum alloy sheet material. In the soaking step, the aluminum alloy ingot is
In the range of 60 to 610 ° C., homogenization treatment is performed for 6 to 24 hours. In a hot rolling step, when the homogenized aluminum alloy ingot is hot-rolled to form a sheet material, after hot rolling, When the temperature of the coiled plate material is 400 to
500 ° C., after which the recrystallized rate of the coiled sheet material cooled is set to 70 to 100%. In the first cold rolling step, the sheet material after the completion of the hot rolling is reduced in a range of 75 to 95%. Cold-rolled so as to be inside, and in the first intermediate annealing step, 1
280-380 ° C at a heating rate in the range of 0-200 ° C / s
, Held at this temperature range for 1 to 30 seconds, then cooled and annealed at a cooling rate in the range of 10 to 200 ° C / s, in the second cold rolling step, the first intermediate annealing The subsequent sheet material is cold-rolled so that the rolling reduction is in the range of 10 to 25%. In the second intermediate annealing step, 1
450-610 ° C at a heating rate in the range of 0-200 ° C / s
, Held at this temperature range for 1 to 30 seconds, then cooled and annealed at a cooling rate in the range of 10 to 200 ° C./s, and then, in the final cold rolling step, a reduction of 45%. After the cold rolling, the coiled sheet material was subjected to one-pass cold rolling so that the temperature of the coiled sheet material became 90 ° C. or more and 140 ° C. or less, and was wound after the winding was completed. It is characterized in that the coil-shaped plate material is held for 1 to 10 hours until it becomes lower than 90 ° C.

By setting the finishing temperature at the time of hot rolling to 400 to 500 ° C., which is higher than the patent application technology previously provided by the present inventors, the recrystallization rate can be set to a high range of 70 to 100%. 75% to 95% in the first cold rolling
Thus, even if cold rolling is performed at a high rolling reduction, the occurrence of side cracks can be prevented. In particular, by increasing the heating rate of the second intermediate annealing and increasing the holding temperature, coarsening of recrystallized grains can be prevented, and relatively fine uniform crystal grains can be obtained.

The high finishing temperature of the hot rolling, and the high heating rate of the second intermediate annealing and the high holding temperature reduce the amount of cubic grains generated during the second intermediate annealing. However, by increasing the first cold rolling reduction to 75 to 95% and limiting the second cold rolling reduction to an optimal range of 10 to 25%, the necessary and sufficient cubic grain orientation after the second intermediate annealing is obtained. Can be generated. When the sheet material after the second intermediate annealing is deep drawn, a slight 0-90 ° ear is generated. When the final cold rolling step is performed on the sheet material in this state, the rolling reduction of the final cold rolling step is relatively low at 45 to 70%, so that the development of the rolling texture is not so large.
As a result, the 45 ° ear and 0-90 ° ear were balanced,
In other words, a plate material with a low ear ratio can be obtained. Furthermore, in the final cold rolling step, the rolling reduction is set to a low range of 45 to 70%, and the temperature of the coiled sheet material after the cold rolling is 90 ° C. or more.
By performing one-pass cold rolling so as to be 140 ° C. or less, and maintaining the temperature of the coiled sheet material after completion of winding at 90 ° C. or more for 1 to 10 hours, the body breaking resistance was excellent. A plate material is obtained.

[0020]

Embodiments of the present invention will be described below in detail. The method for producing an aluminum alloy sheet material for a can body having excellent body breaking resistance according to the present invention is basically based on an ingot of an aluminum alloy as a base material, and each of the following steps set under specific conditions described later. , Soaking process, hot rolling process, first cold rolling process,
It is constituted by sequentially passing through a first intermediate annealing step, a second cold rolling step, a second intermediate annealing step, and a final cold rolling step.

According to the manufacturing method of the present invention, it is possible to use only a single-mill reverse hot rough rolling mill in all of the hot rolling steps. Then, an aluminum alloy plate material having both strength and formability can be obtained. For example, when used as a plate material for manufacturing a deep drawing can such as a DI can, the ear ratio can be reduced as compared with the conventional plate material, and the neck diameter reduction ratio is increased. Also, when forming a DI can, the neck ears are reduced, the deformation of the can body can be prevented, the yield can be improved, and an aluminum alloy sheet material for a can body having excellent cut-out resistance can be obtained. .

As an aluminum alloy used in the production method according to the present invention, Al is used as a basic component.
0.9 to 1.7% by weight, Mn: 0.8 to 1.2% by weight, F
e: 0.30 to 0.55% by weight, Si: 0.25 to 0.45
% By weight, Cu: 0.20 to 0.4% by weight, Zn: 0.05
０0.4% by weight, Ti: 0.02 to 0.2% by weight,
Others require the use of an aluminum alloy containing unavoidable impurities. In the present invention, the symbols “-” used when the content of an element is indicated in a range are as follows. Therefore, unless otherwise stated, 0.9 to 1.7.
What is indicated as "% by weight" means that the composition contains the element in an amount of 0.9% by weight or more and 1.7% by weight or less. In addition, the basic composition itself of the above aluminum alloy is not special, and is within the range of the composition of various aluminum can alloys that are currently used in large quantities. It is suitable for economically and efficiently producing the aluminum alloy sheet of the present invention using the prepared aluminum can as a raw material.

Si in the alloy component is liable to form a compound with Mg contained simultaneously, and has a solid solution hardening action, a dispersion hardening action, and a precipitation hardening action.
It forms a compound with Fe and the like, and has the effect of preventing seizure on a die during ironing. Its content is 0.
If the amount is less than 25% by weight, desired lubricating properties cannot be ensured. If the amount exceeds 0.45% by weight, workability is deteriorated, which is disadvantageous. Fe has an effect of miniaturizing the crystal and preventing seizure on a die during ironing. If the content is less than 0.3% by weight, the desired effect cannot be obtained, and if it exceeds 0.55% by weight, the workability is deteriorated.

Cu easily forms a compound with Mg and contributes to solid solution hardening, dispersion hardening and precipitation hardening. If the content is less than 0.20% by weight, the desired effect cannot be obtained.
If it exceeds 0.4% by weight, the workability is deteriorated. Mn is
The compound easily forms a compound with Fe, Si, Al, etc., has a crystallized phase and a dispersed phase, exhibits a dispersion hardening effect, and has an effect of preventing seizure on a die during ironing. If the content is less than 0.8% by weight, the desired curing properties cannot be obtained, and if it exceeds 1.2% by weight, the workability deteriorates. In addition, Mg has a solid solution strengthening action, enhances work hardenability by rolling, and exhibits a dispersion hardening action and a precipitation hardening action by coexisting with Si and Cu described later. If the content is less than 0.9% by weight, the desired effect cannot be obtained.
If it exceeds 1.7% by weight, the workability will be deteriorated.

Zn has a function of miniaturizing precipitates of Mg, Si and Cu. If the content is less than 0.05% by weight, the desired effect cannot be obtained, and if it exceeds 0.4% by weight, the workability and the corrosion resistance deteriorate. Ti has the effect of making crystal grains finer and improving workability. However, if the content exceeds 0.2% by weight, a coarse compound is formed, and conversely, processability is deteriorated. If the content is less than 0.02% by weight, almost no effect is obtained.

In manufacturing the aluminum-based alloy sheet of the present invention from the above-mentioned aluminum alloy, first, an ingot is cast from a molten aluminum alloy of the composition of the present invention according to a conventional method. At this time, inclusions such as hydrogen gas and oxides are removed, and an ingot is obtained preferably by a semi-continuous casting method. The solidification rate at this time is usually 5 to 20 ° C./sec. The dimensions of the ingot are
For example, it is 1.5 m × 0.5 m × 4 to 5 m. Next, the surface of the ingot is ground by grinding by about 1 to 25 mm to create a flat body having a smooth surface.

The chamfer is then sent to the soaking step of the present invention. This soaking step is generally performed to homogenize microsegregation caused by solidification of the molten metal, precipitate supersaturated solid solution elements, and transfer a metastable phase formed by solidification to an equilibrium phase. In the soaking process, it is important that the homogenization temperature be in the range of 560 to 610 ° C. If the homogenization temperature is lower than 560 ° C., the effect of the second intermediate annealing cannot be obtained, cracks are likely to occur in the hot rolling step and the first cold rolling step, and the ear ratio of the final sheet material increases. If the homogenization temperature exceeds 610 ° C., the ingot may be melted.

In the above soaking step, it is preferable to heat the chamfered body to a homogenizing temperature at a heating rate of 100 ° C./hour or less. If the heating rate exceeds 100 ° C./hour, there is a possibility that partial melting may occur. However, if the heating rate is too slow, the production efficiency decreases. From the above viewpoint, the preferable heating rate in the soaking step is in the range of 10 to 100 ° C./hour.

In the above-mentioned soaking step, the time for maintaining the temperature at the homogenization temperature (homogenization time) is preferably 6 hours or more. If the homogenization time is less than 6 hours, homogenization may not proceed sufficiently. However, if it is too long, there is no effect and the production efficiency decreases. In view of the above, a preferable homogenization time is in the range of 6 to 24 hours. This soaking step is usually carried out in a furnace in a batch mode, since the homogenization time is relatively long.

The hot rolling step is performed to hot-roll the homogenized aluminum-based alloy ingot to form a sheet material. The present invention has one advantage and effect that this hot rolling step can be performed using only a single-mill reverse hot rough rolling mill. This single-mill reverse hot rough rolling mill is provided with seats before and after a single-base hot rolling roll, and gradually thinner by repeatedly passing an ingot between the hot rolling rolls in a reciprocating manner. This is an apparatus generally used as a hot rough rolling mill. The ability to roll using this device means that rolling can be performed without using an expensive hot rolling mill such as a tandem type finishing hot rolling mill or a reverse type hot finishing rolling mill with coil winding devices on both sides. It means that it can be processed, which contributes to simplification of equipment and reduction of manufacturing costs.

In the hot rolling step, the recrystallization rate of the aluminum sheet material wound and cooled as a coil after the completion of the rolling can be set to a high range of 70 to 100%. If the recrystallization ratio is less than 70%, the aluminum alloy sheet material after the hot rolling step becomes hard, and cracks are likely to occur during the subsequent cold rolling. In order to increase the recrystallization rate to 70% or more, it is necessary to increase the rolling reduction and rolling speed in the final hot rolling pass, and to increase the temperature of the coil wound after hot rolling. When the rolling reduction and the rolling speed are low, it is not possible to accumulate a driving force sufficient to cause recrystallization, that is, working energy. Further, if the coil temperature after winding is low (for example, 400
If the temperature is lower than 0.degree. C., recrystallization does not sufficiently occur.

For example, in the process according to the present invention, the first cold rolling reduction is 85%, the second cold rolling reduction is 20%, and the final cold rolling reduction is 60%. In this case, in order to manufacture an aluminum alloy sheet having a thickness of 0.3 mm after the final cold rolling, the thickness after the cold rolling needs to be 6.3 mm. In this case, for example, the rolling reduction of the final pass of hot rolling is about 60% or more, and the rolling speed is about 1%.
By setting it to 50 m / min or more, the temperature of the coiled aluminum alloy sheet after winding can be set to about 400 ° C. or more, and an aluminum alloy sheet having a recrystallization rate of 70% or more can be obtained.

The cause of the decrease in the temperature of the sheet during the hot rolling is mainly due to the fact that heat is taken away by the contact between the sheet and the rolling roll maintained at a low temperature by a coolant (coolant). The ratio of the contact area of the contact portion with the rolling roll at the time of rolling and the volume of the plate material at the contact portion increases as the thickness of the plate at the time of rolling decreases, so that the decrease in the temperature of the plate material increases. Therefore, as the thickness of the sheet material after the final pass becomes smaller, it is necessary to set the rolling reduction and the rolling speed of the final pass to be higher, and to increase the accumulated working energy so that recrystallization occurs even at a low temperature. Furthermore, shorten the contact time with the rolling roll,
It is necessary to prevent a drop in coil temperature.

For example, in an example using a single-mill reverse hot rough rolling mill, the reduction rate of the final hot rolling pass is 50 to 75%, the rolling speed is 150 to 250 m / min, and the sheet after hot rolling is performed. It is possible to make the thickness 5-10 mm and the temperature of the wound coil 400-500 ° C., thereby obtaining a recrystallization rate of 70-100%. Here, when the recrystallization ratio is set in such a high range, the recrystallization ratio is 70%.
As compared with the case of less than, the number of cubic orientation grains generated when recrystallized during the second intermediate annealing is reduced. However, in the final cold rolling step, the rolling reduction is set in a low range (45 to 70).
%), The development of the rolling texture in the final cold rolling is small, and the finally obtained sheet material is 0 to 90%.
A low ear is achieved in which the development of the ° ear and the 45 ° ear is balanced. Note that even if the coil temperature of the wound coil exceeds 500 ° C., the occurrence of cracks during the first cold rolling is not further improved, and surface oxidation occurs until the coil is cooled. It is preferable to set the following.

In the hot rolling step, the rolling start temperature is preferably set to 500 ° C. or higher. If the rolling start temperature is lower than 500 ° C., the rolling load increases, the number of required passes increases, the efficiency decreases, and it becomes difficult to maintain the allowable temperature range immediately after the end of the hot rolling. The starting temperature of the final pass is preferably set to 400 ° C. or higher.
The recrystallization rate is also considered to depend on the cooling rate of the coil after winding.However, even if the aluminum alloy sheet rolled into a coil after rolling is forcibly cooled by air cooling with a fan, sufficient recrystallization can be achieved. Rate (70-100%) is obtained.

In the first cold rolling step,
The cooled sheet material after the completion of the hot rolling step is cold-rolled so that the rolling ratio is in the range of 75 to 95%. If the rolling ratio in this step is less than 75%, the ear ratio becomes large.
The higher the rolling reduction, the more cubic orientation structures having 0-90 ° ears are generated in the second intermediate annealing step described later. However, when the rolling ratio exceeds 95%, it is difficult to prevent cracks generated at the end of the sheet material, and there is a possibility that a break may occur during rolling. If the end is trimmed in order to prevent the breakage, the yield is significantly reduced and the production cost is significantly increased. From the above viewpoints, it is preferable that the rolling reduction in the first cold rolling step is in the range of 75 to 95%.

In the first intermediate annealing step, the cold-rolled sheet material is heated at a heating rate of 10 to 200 ° C./s (10 ° C./s) using a continuous annealing apparatus whose basic structure is shown in FIG.
/ S and 200 ° C / s or less), hold for 1-30s (1s or more and 30s or less) at a holding temperature of 280-380 ° C (280 ° C or more and 380 ° C or less), and cool. Speed range from 10 to 200 ° C / s (10 ° C or higher,
It is preferable to cool at a temperature of 200 ° C. or less.

FIG. 1 shows a continuous annealing apparatus (Continuous Anneal).
In the continuous annealing apparatus A of this example, a long aluminum alloy plate 2 is drawn out from a supply roll 1 and is fed through a shock absorber 3 through a shock absorber 3.
The raw material is supplied to the furnace main body 4 having a length of about 0 m to 100 m, annealed under the above conditions while moving in the furnace main body 4, pulled out from the furnace main body 4 after annealing, and wound up on the take-up roll 7 via the buffer device 6. A device that can According to the continuous annealing apparatus A, the aluminum alloy plate 2 passing through the furnace body 4
Can be subjected to continuous simple treatment, so that the annealing treatment can be performed under more accurate heating and cooling conditions than in a batch type annealing furnace. Then, in the case of the continuous annealing apparatus A, even if the width and the diameter of the coil in a state where the aluminum-based alloy plate 2 is wound around the supply roll 1 are different, in other words, the width and the thickness of the aluminum alloy plate 2 should be treated. Even if the lengths are different, since the annealing process can be performed in the order of production, the intermediate stock increases compared to the batch type annealing furnace where only coils of the same size are carried into the annealing furnace and annealed. Can be suppressed.

This annealing step brings the aluminum base alloy sheet material into a semi-softened state, and sets the YS (Yield strength) after annealing in the range of 100 to 250 MPa, more preferably in the range of 130 to 200 MPa. Is preferred. The yield strength in this range can be achieved by appropriately combining the annealing temperature and time. However, when the annealing temperature is increased and annealing is performed in a short time, more cubic grains are obtained after the second intermediate annealing described below. For this purpose, the heating rate is as high as 10 ° C./s or more, the material is rapidly heated to a high temperature of 280 ° C. or more, and softened to an appropriate range in a short time of 30 s or less. Under such conditions, if annealing is performed so that the proof stress is within this range, a cubic orientation structure having a 0-90 ° ear after the second intermediate annealing described below is generated in an appropriate amount to satisfy the purpose. If the annealing temperature is less than 280 ° C. or the holding time is less than 1 s, sufficient softening cannot be obtained, resulting in a high ear ratio. If the annealing temperature exceeds 380 ° C. or the holding time exceeds 30 s, the softening becomes excessive and the ear rate increases.

The second cold rolling step is a step of performing cold rolling on the sheet material after the first intermediate annealing so that the rolling reduction is within a range of 10 to 25%. In practice, it is preferable that the rolling reduction is in the range of 15% or more and less than 22%.

In the second intermediate annealing step, the sheet material having undergone the second cold rolling step is subjected to an annealing temperature of 450-6.
This is a step of annealing within a range of 10 ° C. and an annealing time within a range of 1 to 30 seconds. This step is a step of sufficiently recrystallizing the plate material that has been subjected to the above-described steps in order to develop an appropriate amount of cubic orientation structure, and to obtain a soft material having 0-90 ° ears. Since the annealing time is short in this step, it is preferable to use the continuous annealing apparatus described above. In this second intermediate annealing step, the annealing temperature is lowered,
When the recrystallization is performed for a long time, the amount of cubic grains obtained by the recrystallization increases. However, since the steps (1) to (3) are performed under the above-described conditions, and the rolling reduction in the final cold rolling step as described later is set to a low value of 45 to 70%, it takes a long time at a low temperature. Recrystallization undesirably results in excessive cubic grains. Therefore, the heating rate is set to 10 ° C./s or more, and heated to 450 ° C. or more,
Complete recrystallization in a short time. In addition, by heating to 450 ° C. or more, Si, Cu, Mg, and the like are solutionized, work hardenability increases, and precipitation hardenability is imparted, so that the rolling reduction in the final cold rolling step is reduced. Even with a low value of 45 to 70%, sufficient material strength can be obtained. In order to enhance the solution effect, it is preferable to increase the heating temperature and lengthen the holding time. However, if the heating temperature is too high, the plate is likely to break, so the upper limit of the heating temperature was 610 ° C. In order to lengthen the heating time, it is necessary to lengthen the furnace length of the continuous annealing furnace or to slow down the plate passing speed, both of which are factors that increase the production cost. So the upper limit is 60
Seconds. Further, even if the cooling rate is too slow, the productivity is reduced, so the lower limit was set to 10 ° C./s. On the other hand, if the heating / cooling rate exceeds 200 ° C./s, distortion tends to occur in the plate material.

In the final cold rolling step, the sheet material after the second intermediate annealing is made to have a predetermined thickness.
Cold rolling is performed in one pass within a rolling ratio of 45 to 70%,
The temperature of the wound coil is set to 90 to 140 ° C. One pass here can be performed by rolling once in a single-stand cold rolling mill, or by performing rolling once in a tandem-type rolling mill in which two or more rolling mills are arranged. You can also. Furthermore, after winding is completed,
Hold for 1 to 10 hours until the coil temperature is less than 90C. If the rolling reduction in this step is less than 45%, buckling and wrinkling are likely to occur during neck molding. If the rolling reduction exceeds 70%, the ear ratio increases and the cut-out resistance deteriorates. In addition, when the coil temperature is less than 90 ° C., or even when the coil temperature is 90 ° C. or more, if it is cooled to less than 90 ° C. within one hour after completion of winding, the work hardenability of the plate material is too low. In addition, wrinkles are likely to occur during deep drawing, redraw forming or bottom forming. On the other hand, when the temperature of the wound coil exceeds 140 ° C., and when the time until the coil becomes less than 90 ° C. exceeds 10 hours, the body breakage resistance is significantly deteriorated.

In general, when cold rolling is performed, the applied processing work is converted into heat, and the material temperature during rolling is increased. On the other hand, the material being rolled is deprived of heat by the contacting rolls and coolant, and is cooled. Normally, the higher the rolling reduction, the larger the calorific value of the former, but the calorific value does not largely depend on the rolling speed. The latter cooling amount decreases as the rolling speed increases. Therefore, the higher the rolling reduction and the higher the rolling speed in the cold rolling process, the higher the material temperature during rolling. The final cold rolling at a rolling reduction of 45 to 70% may be performed by a single-stand cold rolling mill or a tandem-type multi-high rolling mill, but must be performed in one pass as described above. When the cold rolling is performed in two passes, the coil temperature increases in the first pass, but usually the second pass is performed after the coil temperature has decreased to almost room temperature.
In this case, after the rolling in the first pass, age hardening occurs before the coil is cooled, and the strength is significantly increased during the rolling in the second pass. Furthermore, since the rolling reduction in the second pass is low, it is difficult to raise the temperature after rolling to 90 ° C. or higher. As a result, wrinkles are likely to occur during deep drawing or redraw forming. A method in which the second pass rolling is performed immediately after the first pass rolling is also conceivable. However, when the coil is long, the holding time between passes becomes several minutes or more, so that the first problem is completely avoided. Can not. Further, after rolling, the temperature difference in the coil is the largest, and it is difficult to obtain a uniform thickness with the temperature kept high.

When rolling in one pass, it is necessary to set the rolling speed in an appropriate range in order to keep the coil temperature after winding in a predetermined range. If the rolling reduction is low,
Since the calorific value is small, it is necessary to increase the coil temperature before rolling and make it difficult to cool during rolling. On the other hand, when the rolling reduction is high, the amount of heat generated is large, so that it is necessary to sufficiently cool down. After the above steps, the plate is wound into a coil and commercialized as an aluminum alloy plate of the present invention having a predetermined thickness.

In the order described above, a soaking step, a hot rolling step, a first cold rolling step, a first intermediate annealing step, a second cold rolling step, and a second intermediate annealing step,
By performing the final cold rolling step of (1) and (2) to produce an aluminum alloy sheet, when the cup 8 is used to produce an aluminum can as shown in FIG. . In FIG. 2, the rolling direction of the aluminum alloy plate at the bottom of the cup is indicated by an arrow,
The position in the circumferential direction of the cup 8 is represented based on the rolling direction. The 0-90 ears are formed at the locations indicated by the 〇 marks on the upper portion of the cup 8 (the side portions in the case of the aluminum-based alloy plate constituting the cylindrical body).
After the second intermediate annealing, slight ears are generated at the 0-90 ° position, and the ears generated at the 0-90 ° position are further reduced by the final cold rolling. Although ears are also generated at the 45 ° position indicated by, a low ear material that produces small ears balanced at both the 0-90 ° and 45 ° positions is obtained. According to the manufacturing method of the present invention, in the side portion of this aluminum alloy, that is, in the case where the aluminum-based alloy plate is processed into a cylindrical shape, the 0-90 ° ear and the 45 ° ear appearing on the opening side of the cylindrical body. As a result, the ear ratio can be kept low.

[0046]

Next, the present invention will be described in more detail with reference to examples. In the following Examples and Comparative Examples, aluminum alloys having two compositions shown in Table 1 below were used as alloys A and B, respectively, as raw materials.

[0047]

[Table 1]

The molten metal of each of the above alloys is degassed and inclusions are removed by a conventional method, and then an ingot having a weight of 6 t and a thickness of 550 mm is cast by semi-continuous casting.
A 2.5 mm facing was cut to produce a sample of the facing ingot. For each of the samples, under the conditions shown in Table 2 below:
The soaking process, the hot rolling process, the first cold rolling process, the first intermediate annealing process, the second cold rolling process, the second intermediate annealing process, and the final cold rolling process are sequentially performed to obtain an aluminum alloy for a can body. Plate material was manufactured. Conditions of each step other than the notation were as follows for all samples.

Soaking step: heating rate is 50 ° C./average
At this time, the homogenization temperature was 570 ° C. ± 3 ° C., and the homogenization was carried out by keeping the temperature in this temperature range for 8 to 10 hours. Hot rolling step: For Examples 1 to 3 and Comparative Examples 1 to 11, the starting temperature of the final rolling pass is 450 ° C to 5 ° C.
At 00 ° C., the rolling reduction was 62%. The "coil temperature after hot rolling and winding" shown in Table 2 below is the temperature of the aluminum alloy sheet immediately after winding on the coil after the final pass, and was adjusted by the rolling speed (the lower the rolling speed, the lower the rolling speed). After the completion of hot rolling, immediately before winding into a coil, trimming was performed at both ends of each 20 mm in order to remove side cracks generated at both ends in the sheet width direction. For Comparative Examples 12 to 15, using a hot rough rolling mill,
After rolling to 8 mm, it was finish-rolled by a 4-tandem hot rolling mill.

First intermediate annealing step: A floating type continuous annealing apparatus equipped with a furnace body having a length of 15 m was used for 30 minutes.
Heating was performed at an average heating rate of about 20 ° C./s from about 0 ° C. to 280 ° C. The maximum attainable temperature of the material and the time of keeping the temperature at 280 ° C. or higher are as shown in Table 2 below. The average cooling rate from the ultimate temperature to 70 ° C is about 30 ° C / s
Set to. However, in Comparative Examples 14 and 15, a batch-type annealing furnace was used, and the annealing temperature was from (annealing temperature-100) .degree.
10) The average heating rate to 14 ° C. is 14 to 17 ° C./hour (0.0039 to 0.0047 ° C./s),
The holding time was set to the condition shown in Table 2 below, and the cooling was performed at the actual temperature (temperature of the coil itself of the aluminum alloy sheet) of 250.
The furnace was cooled until the temperature reached ℃, and thereafter cooled in the atmosphere. In addition, in order to remove the side crack of the sample immediately before the first intermediate annealing step, each of the 20 mm at both ends in the width direction of the sample was removed.
Part was trimmed.

Second intermediate annealing step: A floating type continuous annealing furnace was used, and the average heating rate from normal temperature to (annealing temperature-100 ° C) was 30 to 100 ° C / sec. “Temperature” in Tables 2 and 3 described below indicates the maximum annealing temperature.
“Time” indicates a time (second) from (maximum ultimate temperature−100) ° C. to the maximum annealing temperature. The cooling rate is
On average from the highest annealing temperature to 70 ° C, about 100 ° C
/ Sec. However, in Comparative Example 9, the batch type annealing furnace was used, and the average heating rate from (annealing temperature −100) ° C. to the annealing temperature was 14 to 17 ° C./hour (0.0039 to 0.000).
47 ° C./s), the holding temperature and the holding time are set to the conditions shown in Table 2 below, and the furnace is cooled until the actual temperature (the temperature of the coil itself of the aluminum alloy sheet) reaches 250 ° C. Cooled in. In Comparative Example 9, after performing the second intermediate annealing, the third intermediate annealing using a floating continuous annealing furnace was performed in the same manner as described above. In Comparative Examples 10 and 11, a batch-type annealing furnace was used, and the average heating rate from (annealing temperature −100) ° C. to the annealing temperature was 14 to
17 ° C./hour (0.0039 to 0.0047 ° C./s), heating to the temperature shown in Table 2, holding for the time shown in Table 2, and further in the same furnace to the third annealing temperature, 14 to 17 ° C.
After heating at a heating rate of / hour and holding the same time, the furnace was cooled until the actual temperature reached 250 ° C., and thereafter, it was cooled in the atmosphere.

Final cold rolling step: An aluminum alloy sheet having a thickness of 0.30 mm was manufactured according to the “final rolling reduction” shown in Table 2. In Examples and Comparative Examples 1 to 8, final cold rolling was performed in one pass. In Comparative Examples 9 to 15, the final cold rolling was performed in two passes. The coil temperature immediately after the completion of the final pass winding is shown in Table 2 below. After winding, 90
Table 2 also shows the time required for cooling to below ° C. The cooling of the coil was performed by air cooling with a fan.
Then, after the end of the final cold rolling, after the elapse of the time shown in Table 2, rewinding was performed by a slitter, and forced air cooling was performed at the time of rewinding.
It cooled to below ° C. Comparative Examples 11, 13, and 15
The materials manufactured in the same process as Comparative Examples 10, 12, and 14 were subjected to stabilized annealing at 145 ° C. for 2 hours after final cold rolling.

As a result of observing the cross-sectional grain structure of the aluminum alloy sheet obtained as a result of the above test, the following Table 2 was obtained.
Are classified by A, B, and C and displayed. A indicates a slightly stretched ultrafine grain structure, B indicates a slightly stretched microcrystalline grain structure, and C indicates an extremely stretched coarse grain structure. Next, after heating the above-mentioned aluminum alloy plate at 210 ° C. for 10 minutes corresponding to the baking conditions at the time of baking coating, JIS
A No. 5 tensile test piece was processed, and a 0.2% proof stress was determined in accordance with JIS B7771. Further, DI processing of a 350 cc beverage can was performed using the above aluminum alloy plate material. Table 2 shows the measurement results of the ear height generated at the upper end of the can after DI processing. In addition, only deep drawing and redrawing are performed, and redrawing cans are sampled without ironing and bottom forming, and the state of unevenness on the inclined portion between the bottom and the can wall is examined. Table 2 and Table 3 show the measurement results.

Next, the second ironing rate at the time of DI processing was lowered, and instead the third ironing rate was increased, whereby the body was easily cut off and the cut-out resistance was evaluated. The ironing rate was set by performing a preliminary test using the material of Comparative Example 11 so that the rate of occurrence of body breakage was about 1%. In this test, 20 types of materials were sequentially changed to examine the rate of occurrence of body breakage. The material was changed when the same material was cut three times with the same material or when the number of moldings reached about 2,000 cans. Such a cycle was performed three times, and about 6000 cans were formed for a sample having a body breakage rate of 0%. In the sample with the highest body breakage rate, the total number of moldings was about 1000 cans.

[0055]

[Table 2]

[0056]

[Table 3]

From the results shown in Tables 2 and 3, the coil temperature after winding in the hot rolling step is preferably 400 to 500 ° C., and the recrystallization rate after cooling is in the range of 70 to 100%. The rolling reduction after the final cold rolling is preferably in the range of 45 to 70%, and the temperature of the coil wound thereafter is preferably 90 ° C. or more and 140 ° C. or less, and one-pass cold rolling is preferably performed. It is preferable that the coil temperature is 90 ° C. or less immediately after winding.
It became clear that it is preferable to hold for more than an hour. That is, in the sample of Comparative Example 1, the temperature of the first intermediate annealing was set to 520 ° C. higher than the upper limit of 380 ° C. of the present invention, and the sample in which the second cold rolling step and the second intermediate annealing step were omitted, that is, the sample of the present invention. This is the case where the semi-softening annealing which is the first intermediate annealing is not performed, and the recrystallization annealing is directly performed, but fine recrystallization is obtained, and the bottom wrinkles do not occur, but the ear height is high. became.

The sample of Comparative Example 2 was a sample in which the temperature of the first intermediate annealing was set to 270 ° C., which is lower than the lower limit of 280 ° C. of the present invention, and the time of the first intermediate annealing was set to 0. Obtained, no bottom wrinkles, no cuts, but ears were raised. The sample of Comparative Example 3 was a sample in which the temperature of the first intermediate annealing was set to 390 ° C. higher than the upper limit of 380 ° C. of the present invention, and the second intermediate annealing step and the second intermediate annealing step were performed. No bottom wrinkles or cuts were observed, but the ears were raised. In the sample of Comparative Example 4, the rolling reduction in the second cold rolling step was 30%, which was larger than the upper limit of 25% of the present invention.
Although the sample was a sample having an excessively high rolling reduction, fine recrystallization was obtained, and bottom wrinkles and cuts were not generated, but the ear height was high. In the sample of Comparative Example 5, the coil temperature after winding was set to 380 ° C lower than 400 ° C, the recrystallization rate after hot rolling was set to 60% lower than 70%, and immediately after winding after hot rolling. In this case, the coil temperature was too low, and the recrystallization rate after cooling was too low. However, the sheet material was broken during the first cold rolling, and the rolling could not be continued.

In the sample of Comparative Example 6, when the temperature of the coil wound after the final cold rolling was too low, fine recrystallized grains were obtained, the ear height was low, and no breakage occurred. Bottom wrinkles were likely to occur and elongation was low. The sample of Comparative Example 7 was a sample in which the coil temperature immediately after winding after the final cold rolling was higher than the upper limit of 140 ° C. of the present invention, but fine recrystallized grains were obtained and bottom wrinkles were hardly generated. However, the ear height was low, but the body was cut off. In the sample of Comparative Example 8, when the time required for the coil temperature after the final cold rolling to be 90 ° C. or less was too short, fine recrystallized grains were obtained, the ear height was low, and no breakage occurred. But wrinkled at the bottom. The sample of Comparative Example 9 conforms to the technique of performing three-stage intermediate annealing in the manufacturing method according to the technique disclosed in Japanese Patent Application Laid-Open No. 2000-26946, to which the present inventors have previously applied for a patent (the third intermediate annealing is performed). And the rolling reduction at the time of final cold rolling was set to 72.7%, which exceeds the upper limit of 70% of the present invention), but the ear height was low, but the crystal grains were coarse and the bottom wrinkles were easily generated. A cut has occurred.

The sample of Comparative Example 10 conforms to the technique of performing three-stage intermediate annealing in the production method according to the technique disclosed in Japanese Patent Application Laid-Open No. 2000-26946, to which the present inventors have previously applied for a patent (first example). A sample in which the rolling reduction in the cold rolling step is 66.2%, which is lower than the lower limit of 75% of the present invention, and the third intermediate annealing step is performed, and the rolling reduction is 85%, which exceeds the upper limit of 70% in the present invention). However, although the ear height was low, the crystal grains were coarse and the strength was low, the bottom wrinkles were easily generated, and the body was broken. The sample of Comparative Example 11 was a sample obtained by subjecting the material obtained in Comparative Example 10 to stabilizing annealing (145 ° C. × 2 hours), and although it was possible to prevent bottom wrinkles from occurring, the body was cut off. The samples of Comparative Examples 12 to 15 are cases where the raw material was manufactured using a tandem hot finishing mill.
The samples of Comparative Examples 12 and 13 are examples of annealing in a continuous annealing furnace after hot finish rolling, and the samples of Comparative Examples 14 and 15 are samples annealed in a batch annealing furnace. This is an example in the case of cold rolling.

In Comparative Examples 12 and 13, the coil temperature after winding was low, the rolling reduction in the first cold rolling was set to 0, the second intermediate rolling was omitted, and the rolling reduction in the final cold rolling was 85%. Although the ear ratio was low in each case, the crystal grains were coarse, while wrinkles were formed on the bottom, and the body was cut off on both sides. Comparative Examples 14 and 15 are samples in which the recrystallization rate is set to 0, the rolling reduction in the first cold rolling is set to 0, and the second cold rolling and the second intermediate annealing are omitted. Then, both sides broke. Further, when the stabilized annealing is not performed, the bottom wrinkle is easily generated. When the stabilized annealing is performed, the bottom wrinkle is improved, but the body tends to be more easily cut. Furthermore, it was also revealed that the sample subjected to batch annealing after hot rolling had low strength.

Comparative Example 16 is a case where the rolling reduction in the final cold rolling step is 42.3%, which is lower than the lower limit of the range of the present invention. Fine crystal grains can be obtained, ear height is low, and bottom wrinkles and body breaks do not occur. The mouth neck proof stress shown in Table 2 was obtained by trimming the upper end opening of the molded DI can and removing the ears, and then heating conditions (2) corresponding to the baking conditions after printing and painting.
(10 ° C. for 10 minutes), and further, neck forming was performed to reduce the diameter of the mouth portion by 3.4%, and the tensile strength of the test piece cut out from the neck formed portion was determined by a tensile test. is there. In Examples 1 to 5, the mouth neck proof stress was 278.
283 MPa, whereas in Comparative Example 16, 29
It shows a high value of 1 MPa. The higher the yield strength of the neck portion, the higher the occurrence rate of neck wrinkles. Comparative Example 17 is a case in which the time until the coil becomes less than 90 ° C. after the final cold rolling winding is 15 hours, which exceeds the upper limit of the present invention, but fine crystal grains are obtained and ear height is low. Does not cause bottom wrinkles,
High breakage rate.

Next, the elongation shown in Table 3 was obtained by processing the manufactured plate material into a JIS No. 5 test piece, and applying a tensile speed of 2 in the rolling direction.
It shows the elongation when subjected to a tensile test at 0 mm / min. From the elongation values shown in Table 3, if the sample is produced by the production method according to the present invention, the value is less than 5%, preferably less than 4%.
In the case of the comparative example, it is apparent that the value varies in the range of 1.9 to 5.2. From the characteristics of the sample of the present invention shown in Table 3, the elongation after the final cold rolling is 20 t% (t is the thickness m
m, which shows 0.3 mm in this test), preferably 15 t% or less. That is, if the elongation is too high, the body breaking resistance is deteriorated, and if the elongation is low, wrinkles are likely to occur in the cup mouth during cup molding,
Since the sample of the present invention has a low final rolling rate, wrinkles hardly occur.

[0064]

The method of the present invention for producing an aluminum-based alloy plate for a can body having excellent body breaking resistance comprises the steps of: homogenizing an aluminum-based alloy ingot in a soaking process; The temperature of the sheet material at the end of rolling is 400 to
Hot rolling so as to have a recrystallization rate of 70 to 100% so as to be 500 ° C., cold rolling so that the rolling rate is 75 to 95% in a first cold rolling step, and a first intermediate annealing step In a range of 1 to 30 s at 280 to 380 ° C. using a continuous annealing device, and cold-rolled in a second cold-rolling step so that a rolling reduction is 10 to 25%;
450-600 ° C, 1-30 in the second intermediate annealing step
Seconds, and the final cold rolling step is a cold-rolling production method in which the rolling ratio falls within the range of 45 to 70%. Using only a hot rough rolling mill, not only can the ear ratio be greatly reduced during deep drawing, but even if the diameter reduction ratio of the neck is increased during can-making, neck ears are less likely to occur, and it has excellent body cutting properties. Aluminum alloy sheet material can be manufactured, the manufacturing cost for manufacturing DI cans and the like can be reduced, and the yield can be greatly improved.

Next, the finishing temperature at the time of hot rolling is set to 400-400.
The range is as high as 500 ° C., the recrystallization rate is as high as 70 to 100%, and the high temperature of 450 ° C. or higher during the second intermediate annealing is 1%.
By heating at a high speed of 0 ° C./s or more and recrystallizing, the amount of cubic orientation grains generated during the second intermediate annealing is suppressed, while the first cold rolling reduction is increased to 75 to 95%. (2) By limiting the cold rolling reduction to the optimal range of 10 to 25%, the cubic grain orientation generated during the second intermediate annealing is increased, and as a result, the amount of cubic grain orientation required and sufficient after the second intermediate annealing is increased. By reducing the final cold rolling reduction rate to 45 to 70%, so that 45 °
It is possible to provide a low-ear-rate plate material in which the ear and the 0-90 ° ear are balanced.

Further, in the final cold rolling step, the rolling reduction is set to a low range of 45 to 70%, and the temperature of the coiled sheet material after the cold rolling is adjusted to 90 ° C. or more and 140 ° C. or less in one pass. By performing cold rolling and holding the coiled sheet material after completion of winding at 90 ° C. or higher for 1 to 10 hours, there is an effect that wrinkles and breakage are less likely to occur during DI molding.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a continuous annealing apparatus used for carrying out the manufacturing method of the present invention.

FIG. 2 is a perspective view of an aluminum can cylinder obtained by processing an aluminum-based alloy plate obtained by the production method of the present invention.

[Explanation of symbols]

A: continuous annealing device, 1: supply roll, 2: aluminum base alloy plate, 3, 6: buffer device, 4: furnace body, 7
... winding roll, 8 ... tubular body.

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁷ identification mark FI theme Court Bu (reference) C22F 1/00 673 C22F 1/00 673 683 683 685 685Z 691 691B 691C 691A 692 692A 692B 694 694A (72) invention Person: Toshihiro Harada 85, Hiramatsu, Susono-shi, Shizuoka Prefecture Inside the Technology Development Center of Mitsubishi Aluminum Co., Ltd. (72) Inventor Koichi Ohori 85-Hiramatsu, Susono-shi, Shizuoka Prefecture, Technology Development Center of Mitsubishi Aluminum Co., Ltd.

Claims (1)

[Claims] 1. Mg: 0.9 to 1.7% by weight, Mn: 0.9% by weight.
8 to 1.2% by weight, Fe: 0.30 to 0.55% by weight, S
i: 0.25 to 0.45 wt%, Cu: 0.20 to 0.4 wt%, Zn: 0.05 to 0.4 wt%, Ti: 0.02 to
An aluminum alloy containing 0.2% by weight, the remainder being an aluminum alloy consisting of unavoidable impurities and Al, is subjected to hot rolling and cold rolling to produce an ingot obtained by semi-continuous casting to produce an aluminum alloy sheet. At this time, in the soaking step, the aluminum alloy ingot is
In the range of 60 to 610 ° C., homogenization treatment is performed for 6 to 24 hours. In a hot rolling step, when the homogenized aluminum alloy ingot is hot-rolled to form a sheet material, after hot rolling, When the temperature of the coiled plate material is 400 to
500 ° C., after which the recrystallized rate of the coiled sheet material cooled is set to 70 to 100%. In the first cold rolling step, the sheet material after the completion of the hot rolling is reduced in a range of 75 to 95%. Cold-rolled so as to be inside, and in the first intermediate annealing step, 1
280-380 ° C at a heating rate in the range of 0-200 ° C / s
, Held at this temperature range for 1 to 30 seconds, then cooled and annealed at a cooling rate in the range of 10 to 200 ° C / s, in the second cold rolling step, the first intermediate annealing The subsequent sheet material is cold-rolled so that the rolling reduction is in the range of 10 to 25%. In the second intermediate annealing step, 1
450-610 ° C at a heating rate in the range of 0-200 ° C / s
, Held at this temperature range for 1 to 30 seconds, then cooled and annealed at a cooling rate in the range of 10 to 200 ° C./s, and then, in the final cold rolling step, a reduction of 45%. After the cold rolling, the coiled sheet material was subjected to one-pass cold rolling so that the temperature of the coiled sheet material became 90 ° C. or more and 140 ° C. or less, and was wound after the winding was completed. A method for producing an aluminum alloy sheet material for a can body having excellent cut-out resistance, wherein the coil-shaped sheet material is held for 1 to 10 hours until the temperature thereof becomes lower than 90 ° C.