JP6372984B2 - Manufacturing method of aluminum alloy plate for can body with excellent distribution hole resistance - Google Patents

Description

The present invention relates to the production how the aluminum alloy plate for a can body having excellent fluid-tight communication pinhole resistance.

  In general, the can body includes a can with a can lid wound around its open end and a bottle can with a cap screwed into its open end, filled with beverages and other contents, and distributed in the market. doing. Such a can body is conventionally formed by DI processing performed by drawing and ironing a plate material made of an aluminum alloy such as JIS 3004 (AA3004) or JIS3104 (AA3104). The ironing process as described above is usually performed in multiple steps on an aluminum alloy plate, thereby producing a can body.

Conventionally, in the distribution process of the can body as described above, for example, the sharp body contacts or collides with the body portion of the can body, the body portions of adjacent can bodies collide, or between the cans and the cans. By rubbing in a state where a foreign object is sandwiched, breakage of a minute hole or the like called a distribution pinhole may occur, causing problems such as leakage of contents.
Although it is conceivable to increase the thickness of the barrel as an effective means for solving the above-mentioned problem of pinholes, the material of the can body material can be used even if the barrel thickness is simply increased. Since the amount increases, there is a problem that it is not economical and the weight of the can body increases.
In view of this, an aluminum alloy plate suitable for a can body has been developed by adjusting the composition of the aluminum alloy plate constituting the can body and improving the manufacturing process.

For example, as an example, Si: 0.2-0.8% by mass, Fe: 0.3-0.7%, Cu: 0.15-0.5%, Mn: 0.4-1.5 %, Mg: 0.8-6.0% and Ti: 0.001-0.15% aluminum alloy sheet for can body proposed with a proof stress of 300 N / mm ² or more (See Patent Document 1).
In the aluminum alloy plate described in Patent Document 1, the proof stress value is 240 to 300 N / mm even when the material component composition of the can body is set to the above-described value and the thermal history is obtained by coating the resin film. ² can be obtained.

As other examples, Mn: 0.7 to 1.5%, Mg: 0.8 to 1.5%, Fe: 0.35 to 0.5%, Si: 0.1 to 0% by mass .5%, Cu: 0.1 to 0.3%, Ti: 0.1% or less, B: 0.1% or less, an aluminum alloy plate containing a maximum n value of the change curve of work hardening index An aluminum alloy plate for can bodies of 0.1 or more has been proposed (see Patent Document 2).
The aluminum alloy plate described in Patent Document 2 is held at 180 to 220 ° C. for 5 to 30 minutes, and the strength after painting and baking performed by holding at the maximum attained temperature of 210 to 260 ° C. within 2 minutes is 250 MPa or more. Have been described.

Furthermore, as another example, Mg: 0.8-1.5% by weight ratio, Mn: 0.5-1.5%, Fe: 0.35-0.5%, Si: 0.2-0 .35%, Cu: 0.1-0.3%, Ti: 0.1% or less, B: 0.05% or less aluminum alloy plate, work hardening index with respect to the Mn solid solution amount by weight ratio An aluminum alloy plate for a can body having a maximum n value of 0.1 or more of the change curve is proposed (see Patent Document 3).
The aluminum alloy plate described in Patent Document 3 is described as having a rolling direction yield strength of 250 MPa or more after a heat treatment equivalent to paint baking.

JP 2001-003130 A JP 2006-283112 A JP 2006-291326 A

According to the techniques described in these Patent Documents 1 to 3, it was possible to improve the material yield strength and to improve the yield strength after painting and baking or after attaching the resin film.
However, it is also effective to increase the material strength of the aluminum alloy plate, but because the moldability of the can has deteriorated due to the thinning of the side wall of the can body, when the strength of the aluminum alloy material is increased to a certain level, There is a problem that the formability of the aluminum alloy material is lowered and it becomes difficult to form the can shape itself.
From such a background, it was necessary to find a method for improving the flow-resistant pinhole performance in addition to increasing the thickness of the side wall of the can body and increasing the strength of the aluminum alloy material.

  This type of aluminum alloy material for can bodies is made by processing the ingot obtained by adjusting the alloy composition ratio until the desired thickness is obtained by hot rolling, followed by cold rolling and intermediate annealing. An aluminum alloy plate for a can body is obtained by processing to a desired plate thickness by a treatment applied several times. Further, the plate material obtained after the cold rolling is wound in a coil shape and accommodated in an annealing furnace, annealed under the target temperature control, then unwound and sent to the cold rolling apparatus.

As a result of studying the manufacturing method of the aluminum alloy material as described above, the present inventors have found that when the workability of the aluminum alloy material is high, the distribution-resistant pinhole performance tends to increase. In addition, as a manufacturing method for improving the work hardenability of the aluminum alloy material, it is preferable that the cold rolling rate after the intermediate annealing is low, and it is preferable that the coil temperature immediately after rolling in the final cold rolling pass is lowered. I found it.
As a result of further research, it was found that even if the cold rolling rate after the final intermediate annealing is low, the desired work curability cannot always be obtained when the coil temperature immediately after rolling is high. Further, it has been found that even if the coil temperature immediately after rolling in the final cold rolling pass is low, the desired work curability cannot always be obtained even when the cold rolling rate after the final intermediate annealing is high.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a manufacturing how the aluminum alloy material of the work hardenability of the raised aluminum alloy sheet for a can body which can increase the fluid tight communication pinhole performance .

In order to solve the above problems, the present invention employs the following configuration.
The manufacturing method of the aluminum alloy plate for can bodies excellent in circulation pinhole resistance according to the present invention is Si: 0.2 to 0.5%, Fe: 0.3 to 0.7%, Cu: 0.0. 2 to 0.5%, Mn: 0.5 to 1.3%, Mg: 0.9 to 1.5%, Cr: 0.001 to 0.10%, Zn: 0.05 to 0.30% , Ti: 0.03 to 0.10 %, with the balance being Al and inevitable impurities, the aluminum alloy ingot is hot-rolled and cold-rolled to obtain a predetermined plate thickness, followed by continuous annealing. Intermediate annealing is performed to obtain an intermediate plate, and this intermediate plate is further cold-rolled to obtain an aluminum alloy plate having a thickness of 0.220 mm to 0.265 mm and a proof stress after baking of 265 MPa to 295 MPa. This is a method for producing an aluminum alloy plate with excellent The cold rolling rate after the final intermediate annealing is 30% or more, the coil temperature immediately after rolling in the final cold rolling pass is 80 ° C. or higher and 150 ° C. or lower, and the conditions for cold rolling after the final intermediate annealing are as follows: It is characterized by satisfying the following formula.
FT ≦ 515-6 × CR (1) Formula where, in the formula (1), CR: cold rolling rate (%) after the final intermediate annealing, FT: coil temperature immediately after rolling in the final cold rolling pass (° C. ).

In the manufacturing method of the aluminum alloy plate for can bodies excellent in circulation pinhole resistance of the present invention, the Ti content is preferably in the range of 0.03 to 0.04% by mass.

As described above in detail, according to the present invention, the coil temperature immediately after the final cold rolling pass is based on the relationship of the cold rolling rate after the final intermediate annealing of 30% or more and FT ≦ 515-6 × CR. In relation to the above, the coil temperature immediately after the final cold rolling pass is controlled in the range of 80 ° C. or higher and 150 ° C. or lower in relation to the above formula, so that can body excellent in circulation pinhole resistance An aluminum alloy plate can be provided.
In order to manufacture the aluminum alloy plate for the can body, the final production is performed based on the conditions of the above formula using an aluminum alloy ingot in which Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti are defined in a predetermined range. It is necessary to control the cold rolling rate after the intermediate annealing and the coil temperature immediately after the final cold rolling pass.
Moreover, according to the present invention, an aluminum alloy plate for a can body can be provided that has a high strength of the can body portion and excellent resistance to distribution pinholes.

FIG. 1 illustrates a process for manufacturing a can body by DI processing of an aluminum alloy plate for a can body according to the present invention. FIG. 1 (a) is a perspective view of a plate material (blank), and FIG. FIG. 1C is a perspective view of the cup-shaped can body after the re-drawing process, and FIG. 1D is a perspective view of the bottomed cylindrical can body after the ironing process. FIG.1 (e) is a perspective view of a can body. FIG. 2 is a diagram showing the relationship between the cold finish temperature and the cold rolling rate when the can body aluminum alloy sheet manufacturing method according to the present invention is carried out.

One embodiment of an aluminum alloy plate for a can body having excellent flow-resistant pinhole properties according to the present invention will be described below.
As an example, the aluminum alloy plate for can bodies having excellent flow-resistant pinhole resistance according to the present embodiment is, by mass, Si: 0.2 to 0.5%, Fe: 0.3 to 0.7%, Cu: 0.2% to 0.5%, Mn: 0.5% to 1.3%, Mg: 0.9% to 1.5%, Cr: 0.001% to 0.10% Zn: 0.05% or more and 0.30% or less, Ti: 0.05% or more and 0.10% or less, and the balance is preferably composed of Al containing inevitable impurities.
It is preferable that the plate | board thickness of the aluminum alloy plate for can bodies of this embodiment is the range of 0.220 mm or more and 0.265 mm or less. Moreover, the aluminum alloy plate for can bodies is preferably in a range of 265 MPa to 295 MPa as a material yield strength after baking (210 ° C., 10 minutes).

  The reason why the thickness of the aluminum alloy plate for can bodies is 0.220 mm or more is to obtain the strength necessary for the can body and to obtain the can body thickness necessary for maintaining the can shape. If the plate thickness is less than 0.220 mm, it becomes difficult to obtain the strength necessary for the can body, and it becomes difficult to maintain the can shape. The reason why the thickness of the aluminum alloy plate for the can body is set to 0.260 mm or less is to suppress an increase in the weight of the can and to enable economical production. If the plate thickness exceeds 0.260 mm, the weight of the can body increases, the cost of the can body increases, and it is not economical.

[Ingredient composition]
Hereinafter, the component composition limited in the aluminum alloy plate for can bodies of this invention is demonstrated. In addition, content of each element described below is mass% unless otherwise specified, and includes an upper limit and a lower limit unless otherwise specified. Therefore, for example, the notation of 0.2 to 0.5% means 0.2% or more and 0.5% or less.

"Si" 0.2-0.5%
In the aluminum alloy plate for can bodies of the present invention, Si forms an intermetallic compound together with Mg or the like contained at the same time, and improves the strength by solid solution hardening, precipitation hardening and dispersion hardening, and Al-Mn-Fe. It is contained in the intermetallic compound and has the effect of preventing seizure against the die during ironing.
If the Si content is less than 0.2%, sufficient strength cannot be obtained, and desired lubrication characteristics cannot be ensured. When the Si content exceeds 0.5%, the strength becomes excessively high, and when the can body is made, it becomes easy to be cut out of the cylinder and the workability deteriorates. In addition, intermetallic compounds of Mn, Fe, Mg, Cu, and Al cannot be solutionized, and the toughness is lowered and pinholes are easily generated. Therefore, the Si content is preferably in the range of 0.20 to 0.5%. Even within this range, the Si content can be selected in the range of 0.29 to 0.33%.

"Fe" 0.3-0.7%
Fe increases the precipitation amount of Al-Mn-Fe intermetallic compounds in the aluminum alloy sheet for can bodies of the present invention, and prevents the formation of fine crystals and seizure to the die during ironing processing. Has the effect of
If the Fe content is less than 0.3%, the amount of Al—Mn—Fe intermetallic compound deposited becomes too small, and seizure to the ironing mold tends to occur. If the Fe content exceeds 0.7%, the amount of the Al—Mn—Fe intermetallic compound is excessively increased, the workability is deteriorated due to a decrease in toughness, and pinholes are easily generated. Therefore, the Fe content is preferably in the range of 0.3 to 0.7%. Even within this range, the Fe content can be selected in the range of 0.43 to 0.45%.

"Cu" 0.2-0.5%
Cu forms an intermetallic compound with Mg or the like in the aluminum alloy plate for a can body of the present invention, and has an effect of increasing strength by solid solution hardening, precipitation hardening, and dispersion hardening.
If the Cu content is less than 0.2%, a sufficient strength improvement effect cannot be obtained. If the Cu content exceeds 0.5%, side cracks are likely to occur, the rollability is lowered, the strength is too high, and the body is likely to be cut when it is made as a can body. In addition, the intermetallic compound with Mg, Si, and Al cannot be in solution, and the workability deteriorates due to a decrease in toughness, and pinholes are likely to occur. Therefore, the Cu content is preferably in the range of 0.2 to 0.5%. Even within this range, the Cu content can be selected in the range of 0.27 to 0.4%.

"Mn" 0.5-1.3%
In the aluminum alloy plate for can bodies of the present invention, Mn forms an Al-Mn-Fe intermetallic compound, becomes a crystallization phase and a dispersed phase, exhibits a dispersion hardening action, and is used as a die during ironing molding processing. On the other hand, it has the effect of preventing seizure.
If the Mn content is less than 0.5%, the amount of the Al—Mn—Fe intermetallic compound becomes too small to obtain sufficient curing characteristics, and seizure to the ironing mold tends to occur. When the content of Mn exceeds 1.3%, the amount of Al—Mn—Fe intermetallic compound becomes too large, workability deteriorates due to a decrease in toughness, and pinholes are likely to occur. Therefore, the Mn content is preferably in the range of 0.5 to 1.3%. Even within this range, the Mn content can be selected in the range of 0.98 to 1.0%.

"Mg" 0.9-1.5%
In the aluminum alloy plate for can bodies of the present invention, Mg has a solid solution strengthening action, enhances work hardening at the time of rolling, and exhibits dispersion hardening and precipitation hardening action by coexisting with Si and Cu. To improve.
If the Mg content is less than 0.9%, sufficient strength cannot be obtained. If the Mg content exceeds 1.5%, side cracks are likely to occur, the rollability is reduced, the strength is too high and the workability is lowered, and the can body is cut when it is made as a can body. Is likely to occur. Therefore, the Mg content is preferably in the range of 0.9 to 1.5%. Even within this range, the Mg content can be selected from a range of 1.12 to 1.38%.
"Cr" 0.001-0.10%
In the aluminum alloy plate for a can body of the present invention, Cr exhibits the effect of preventing crystal seizure and die seizure during ironing. If the Cr content is less than 0.001%, the desired effect cannot be obtained, and if it exceeds 0.10% by mass, it becomes brittle and the workability deteriorates. Even within this range, the Cr content can be selected in the range of 0.02 to 0.03%.

“Zn” Zn: 0.05 to 0.30%
Zn has the effect | action which refines | miniaturizes the intermetallic compound of Mg, Si, and Cu which precipitates in the aluminum alloy plate for can bodies of this invention. When Zn is contained, used aluminum cans and recycled materials can be effectively used as raw materials. If the content is less than 0.05%, a desired fine effect cannot be obtained. When the Zn content exceeds 0.30%, the corrosion resistance deteriorates. Therefore, the Zn content is preferably in the range of 0.05 to 0.30%. Even within this range, the Zn content can be selected in the range of 0.14 to 0.16%.
“Ti” Ti: 0.03 to 0.10 %
Ti has the effect of refining crystal grains and improving workability in the aluminum alloy plate for can bodies of the present invention. However, if the Ti content exceeds 0.10%, a coarse intermetallic compound is produced and workability is reduced, and toughness is lowered and pinholes are likely to occur. Therefore, the Ti content is preferably 0.03 to 0.10 % . Even within this range, the content of Ti can be selected in the range of 0.03 to 0.04%.

[Method for producing aluminum alloy sheet]
The aluminum alloy plate for can bodies according to the present invention can be obtained by ordinary melting, casting, hot rolling, and cold rolling applied when manufacturing this type of aluminum alloy plate.
An aluminum alloy sheet for can bodies having a target sheet thickness of 0.220 mm or more and 0.265 mm or less by performing final intermediate annealing by continuous annealing at a predetermined sheet thickness during a cold rolling pass. Get.
As conditions for final intermediate annealing by continuous annealing, it is preferable to heat to a temperature of 400 ° C. or more and 600 ° C. or less for 1 second or more and 2 minutes or less, and then cool at a cooling rate in the range of 10 to 200 ° C./s.
If the intermediate annealing temperature is less than 400 ° C. and the annealing time is 1 second or less, the recrystallized structure may become inhomogeneous, which is not preferable. Further, by setting the temperature to 400 ° C. or higher and 1 second or longer, Si, Cu, Mg, etc. are dissolved and precipitation hardenability is imparted, so that sufficient material strength after baking (210 ° C., 10 minutes) can be obtained. . When the temperature of the intermediate annealing exceeds 600 ° C., oxidation of the plate material surface tends to proceed, which is not preferable. When the annealing time exceeds 2 minutes, the productivity decreases. Therefore, the intermediate annealing temperature is preferably in the range of 400 ° C. to 600 ° C., and the annealing time is preferably in the range of 1 second to 2 minutes. When the cooling rate of the intermediate annealing is 10 ° C./s or less, the productivity is lowered, and precipitation in the cooling process of Si, Cu, Mg, etc. that are solutionized in the intermediate annealing tends to occur. When the cooling rate of the intermediate annealing exceeds 200 ° C./s, the plate material is likely to be distorted. Therefore, the cooling rate of the intermediate annealing is preferably 10 ° C./s or more and 200 ° C./s or less. Moreover, you may anneal as needed in the middle of the pass of the cold rolling before the said intermediate annealing. Although the intermediate annealing may be performed a plurality of times, it is preferable to define the above-mentioned conditions as conditions for the final intermediate annealing.

In the manufacturing process, the cold rolling rate after the final intermediate annealing is preferably 30% or more, and the coil temperature immediately after rolling in the final cold rolling pass is preferably 80 ° C. or more and 150 ° C. or less, Furthermore, it is preferable that the following formula (1) is satisfied as a condition for cold rolling after the final intermediate annealing. However, in the following formula (1), it is preferable to define CR: cold rolling rate (%) after final intermediate annealing and FT: coil temperature (° C.) immediately after rolling in the final cold rolling pass. Note that the cold rolling rate (%) after the final intermediate annealing is represented by {1- (plate thickness after the final cold rolling pass / plate thickness in the final intermediate annealing)} × 100.
FT ≦ 515-6 × CR (1) formula

Necessary for the can by setting the cold rolling rate after the final intermediate annealing to 30% or more and defining the range in relation to the coil temperature immediately after the final cold rolling based on the above-mentioned formula (1) At the same time as obtaining high strength, it is possible to obtain effective work curability for obtaining flow-resistant pinhole performance.
It is desirable that the coil temperature when the plate material is wound immediately after the final cold rolling is a temperature of 80 ° C. or higher. If the coil temperature is less than 80 ° C., it is necessary to slow the rolling speed, and there is a possibility that economical rolling cannot be performed.

  It is desirable that the coil temperature when the plate material is wound immediately after the final cold rolling is set to a temperature of 150 ° C. or lower. If the coil temperature is set to a temperature exceeding 150 ° C., there is a problem that the risk of ignition of the rolling oil increases.

[Can manufacturing process by DI processing]
Hereinafter, an example of a process for obtaining a can body by performing DI processing on an aluminum alloy plate for a can body to produce a can body will be schematically described with reference to FIG.
First, as shown in FIG. 1 (a), a can body aluminum alloy material is punched to obtain a disk-shaped plate material (blank) 5 having a diameter D1.
Next, the disk-shaped plate material 5 is drawn to form a cup-shaped can body 6 having an outer diameter D2 as shown in FIG.
Next, the cup-shaped can body 6 is redrawn to obtain a cup-shaped can body 7 having an outer diameter D3 as shown in FIG. The ratio between D1 and D3 is, for example, 2.0 to 2.7.

Next, ironing is performed to form a bottomed cylindrical can body 8 as shown in FIG. The open end portion of the bottomed cylindrical can body 8 has an uneven shape that undulates in the direction of the can axis.
Next, the open end portion of the bottomed cylindrical can body 8 shown in FIG. 1 (d) is cut, and the size in the can axis direction, that is, the height is processed equally over the entire circumference, A can body 10 having a circular cross section shown in FIG.

  As described above, according to the aluminum alloy plate for a can body excellent in flow resistance pinhole property of the present embodiment, the plate thickness is thinly formed as 0.220 mm or more and 0.260 mm or less, and the cold after the final intermediate annealing is performed. The rolling rate is set to 30% or more, the coil temperature immediately after rolling in the final cold rolling pass is set to 80 ° C. or higher and 150 ° C. or lower, and the conditions of cold rolling after the final intermediate annealing are as follows: ≦ 515-6 × CR (1) ”is satisfied, so that it is possible to suppress a decrease in economy and an increase in the weight of the can body due to an increase in the wall thickness of the can body side wall, and a high aluminum material. While suppressing a decrease in formability due to strengthening, it is possible to obtain a moderate yield strength after baking, to improve the piercing strength of the barrel portion, and to prevent the occurrence of distribution pinholes in the barrel portion.

  Therefore, by using the aluminum alloy plate for a can body of the present invention, a can body having excellent circulation pinhole resistance can be produced without increasing the production cost.

[Material strength after baking (210 ° C x 10 minutes)]
The can body after DI processing is heated to a temperature of 180 to 230 ° C. by drying after cleaning and chemical conversion treatment, or by baking treatment after external printing or internal coating. This heating generally changes the strength of the can bottom and the trunk. The strength after heating differs depending on the amount of strain during DI molding. Since the bottom of the can body has a small distortion during DI molding, the strength after heating is almost equal to the strength after heating the aluminum alloy plate which is a material before DI processing. For this reason, the intensity | strength after baking (heating) the aluminum alloy plate which is a raw material can be used as a standard of the intensity | strength of a bottom part. In the present invention, the heating condition for this is 210 ° C. × 10 minutes.

The material yield strength after baking of the aluminum alloy plate for can bodies of the present invention is preferably 265 MPa or more and 295 MPa or less as the yield strength after baking under the above conditions.
If the material yield strength after baking under the above-mentioned conditions is less than 265 MPa, sufficient pressure strength of the can body after canning by DI processing and paint baking cannot be obtained.
Moreover, since it will become difficult to shape | mold into a can shape if the raw material yield strength after baking on the above-mentioned conditions seems to exceed 295 MPa, 295 MPa or less is desirable.

Hereinafter, although an Example is shown and the aluminum alloy plate for can bodies excellent in the distribution | circulation resistance pinhole property of this invention is demonstrated in more detail, this invention is not limited to this Example.
In the present example, No. 1 to No. 15 aluminum alloy plates for can bodies were produced in the following steps under the respective component compositions and production conditions shown in Table 1 below, and evaluation was performed for each item described below. .

[Production process of aluminum alloy plate for can body]
The aluminum alloy of the components shown in Table 1 below is melted, and this molten metal is degassed and inclusions removed by a conventional method, and cast into a slab having a thickness of 550 mm, a width of 1.5 m, and a length of 4.5 m by semi-continuous casting. did. Next, the slab was subjected to a soaking treatment at 565 ° C. and then hot-rolled. Then, it cold-rolled to the predetermined plate | board thickness in the range of 0.38mm-1.15mm. Then, continuous annealing (IA-CAL) is performed by heating to a temperature of 420 ° C. or more and 600 ° C. or less for 1 second or more and 60 seconds or less, and then cooling at a cooling rate of 10 ° C./s or more and 100 ° C./s or less. Cold-rolled to a final plate thickness of 23 mm. 1-No. Fifteen samples were obtained.
The coil temperature (° C.) immediately after the end of the final cold rolling indicates the temperature measured with a contact thermometer from the end face side of the coil immediately after the end of the final cold rolling pass.

  In addition, each sample of aluminum alloy plate for can body was heated (baked) at 210 ° C. for 10 minutes, and then a JIS No. 13B test piece was taken according to JISZ2241, and pulled so that the tensile direction was parallel to the rolling direction. It used for the test and calculated | required 0.2% yield strength. The slope in the linear regression between the logarithm of the true stress and the logarithm of the true strain was obtained as an n value from the 0.2% proof stress point to just before the break, and this n value was used as an index of work hardening.

[Measurement of can body making and piercing strength]
The aluminum alloy plates for can bodies of the examples and comparative examples obtained in the above-described steps were punched out to obtain a disk-shaped plate material having a diameter of 149 mm (see FIG. 1 (a)). This disk-shaped plate material is subjected to DI processing, and drawing and ironing are performed until the thinnest part thickness T2 of the body reaches 0.09 mm. Can).

  Of the body part of the can body obtained, the plate is cut out from each position inclined 60 ° upward from the grounding part in the can axis direction and inclined by 0 °, 45 °, 90 ° from the rolling direction of the can bottom, and the piercing strength is A sample for measurement was used. The sample cut out from the can body was pressed in a direction perpendicular to the sample plate surface with a presser having a curvature radius (tip radius) of 0.5 mm, and the pressing force when a hole was formed was measured. A puncture test was carried out to determine the puncture strength, with the deformation at a position away from a radius of 10 mm centered on the portion pressed by the presser and restrained by a mold and pierced by the presser. The moving speed of the presser in the direction perpendicular to the plate surface was set to 5 mm / min.

Tables 1 and 2 show the composition components, production conditions, and evaluation test results of each example and comparative example.
In addition, IA-CAL shown in the column of the intermediate annealing of Table 1 has shown having performed the continuous intermediate annealing between cold rolling and cold rolling in the aluminum alloy plate preparation process.

  From the results shown in Tables 1 and 2, the desired condition in the present invention, that is, after cold rolling, final intermediate annealing by continuous annealing is performed to obtain an intermediate plate material, and this intermediate plate material is 0.220 by cold rolling. A method for producing an aluminum alloy sheet having a thickness of ˜0.265 mm, wherein the cold rolling rate after the final intermediate annealing is 30% or more, the coil temperature of the final cold rolling pass is 80 to 150 ° C., and the final intermediate annealing It turns out that the aluminum alloy plate for can bodies excellent in circulation pinhole resistance can be manufactured by setting it as the conditions which satisfy | fill the following formula | equation as conditions of subsequent cold rolling. FT ≦ 515-6 × CR (1) formula

On the other hand, the sample No. 6 (Comparative Example 1) was a sample having a relationship of FT> 515-6 × CR, the n value was decreased, and the piercing strength was also decreased.
Moreover, the sample of sample No. 9 (comparative example 2) was a sample having a relationship of FT> 515-6 × CR, the n value was decreased, and the piercing strength was also decreased.
The sample of Sample No. 11 (Comparative Example 3) was a sample having a relationship of FT> 515-6 × CR, the n value was decreased, and the piercing strength was also decreased.
From the above results, in order to produce an aluminum alloy plate for can bodies having excellent circulation pinhole resistance, the coil temperature after final cold rolling and the final value are satisfied so as to satisfy the relationship of FT ≦ 515-6 × CR. It can be seen that it is important to control the cold rolling rate after the intermediate annealing.

As described above, among the samples shown in Tables 1 and 2, with respect to the samples Nos. 1 to 14, FIG. 2 shows the temperature FT (° C.) immediately after rolling immediately after the final cold rolling pass and cold rolling after the final intermediate annealing. The relationship of rate CR (%) was shown.
As is clear from the relationship shown in FIG. 2, the composition ratio shown in Table 1 is satisfied by satisfying the relationship shown in the above equation (1), FT ≦ 515-6 × CR, as shown in Table 2. Aluminum alloy for a can body that has excellent piercing strength and exhibits desired work-hardening properties in an aluminum alloy plate having a thickness of 0.220 mm to 0.265 mm, specifically, a thickness of 0.229 mm to 0.231 mm It can be seen that the plate can be manufactured.
Moreover, although the sample of No. 15 was a sample with a cold rolling rate of 25%, the cold rolling rate was insufficient, and thus sufficient post-baking proof stress could not be obtained.

5 ... Plate material (blank), 6 ... Cup-shaped can body, 7 ... Cup-shaped can body, 8 ... Bottomed cylindrical can body,
10 ... can body, 11 ... body, 12 ... bottom.

Claims (2)

In mass%, Si: 0.2 to 0.5%, Fe: 0.3 to 0.7%, Cu: 0.2 to 0.5%, Mn: 0.5 to 1.3%, Mg: 0 .9 to 1.5%, Cr: 0.001 to 0.10 % , Zn: 0.05 to 0.30 %, Ti: 0.03 to 0.10 % , the balance being Al and inevitable The aluminum alloy ingot made of impurities is hot-rolled and cold-rolled to obtain a predetermined plate thickness, and then subjected to final intermediate annealing by continuous annealing to obtain an intermediate plate material, which is further subjected to cold rolling. A method for producing an aluminum alloy plate for a can body having a thickness of 0.220 mm or more and 0.265 mm or less and having a resistance to pinhole resistance that provides an aluminum alloy plate having a proof stress after baking of 265 MPa or more and 295 MPa or less,
The cold rolling rate after the final intermediate annealing is 30% or more, the coil temperature immediately after rolling in the final cold rolling pass is 80 ° C. or more and 150 ° C. or less, and the conditions for cold rolling after the final intermediate annealing are as follows: The manufacturing method of the aluminum alloy plate for can bodies which is excellent in distribution | distribution pinhole property characterized by setting it as the conditions which satisfy | fill the following formula | equation.
FT ≦ 515-6 × CR (1) Formula where, in the formula (1), CR: cold rolling rate (%) after the final intermediate annealing, FT: coil temperature immediately after rolling in the final cold rolling pass (° C. ). The method for producing an aluminum alloy plate for a can body having excellent circulation pinhole resistance according to claim 1, wherein the content of Ti is in the range of 0.03 to 0.04% by mass.

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