WO2007052416A1

WO2007052416A1 - Cold-rolled aluminum alloy sheet for bottle can with excellent neck part formability and process for producing the cold-rolled aluminum alloy sheet

Info

Publication number: WO2007052416A1
Application number: PCT/JP2006/318241
Authority: WO
Inventors: Katsura Kajihara; Kiyohito Tsuruda
Original assignee: Kabushiki Kaisha Kobe Seiko Sho
Priority date: 2005-11-02
Filing date: 2006-09-14
Publication date: 2007-05-10
Also published as: US20080302454A1; EP1944384A1; CA2625098A1; JP3913260B1; KR20080058453A; JP2007126706A; CN101268207A; EP1944384A4

Abstract

A cold-rolled aluminum alloy sheet for bottle cans which has a composition containing 0.7-1.5 mass% Mn, 0.8-1.7 mass% Mg, 0.1-0.7 mass% Fe, 0.05-0.5 mass% Si, and 0.1-0.6 mass% Cu, with the remainder being Al and unavoidable impurities. In the structure, the number of dispersed particles having a size of 0.05-1 µm, as determined through an examination with a TEM at a magnification of 5,000-15,000 diameters, is 50-400 per 300 µm2, the proportion of dispersed particles having a size of 0.3 µm or larger in these dispersed particles being 15-70% by number based on all these dispersed particles.

Description

Specification

Aluminum alloy cold-rolled sheet for bottle cans with excellent neck formability and method for producing the aluminum alloy cold-rolled sheet

Technical field

TECHNICAL FIELD [0001] The present invention relates to an aluminum alloy cold-rolled plate (bottle can material plate) having excellent neck formability of a bottle can as a can body material for a bottle can (beverage can). The aluminum alloy cold rolled sheet referred to in the present invention is a rolled sheet (cold rolled sheet) rolled through hot rolling and cold rolling. Hereinafter, the aluminum alloy is also referred to as an A1 alloy.

Background art

[0002] As an aluminum-based beverage can, a two-piece aluminum can obtained by seaming a can body and a can lid (can end) is widely used. In this two-piece aluminum can, the body is formed by subjecting a predetermined aluminum plate to can body forming such as cutting and DI forming (drawing and ironing), and then necking the body. The mainstream is one with a smaller end diameter than the body diameter (hereinafter referred to as a two-piece aluminum can).

[0003] In such a two-piece aluminum can, the drawing ratio of the diameter of the end portion relative to the diameter of the body portion is relatively small, so that the neck force is relatively easy.

[0004] Conventionally, as the cold rolled plate for the can body, hard plate strengths such as JIS3004 alloy and 3104 alloy, which are A1-Mg-Mn alloys, have been widely used! This JIS3004 alloy and 3104 alloy are excellent in ironing workability, and show relatively good formability even when cold rolled at a high rolling rate to increase strength. It is considered preferable.

[0005] On the other hand, in recent years, there has been an increasing need for bottle-shaped aluminum cans (hereinafter referred to as bottle cans! /) That have a body, a mouth, and a screw cap! In such a bottle can, since the drawing ratio of the diameter of the mouth portion to the diameter of the body portion is larger than that of the two-piece aluminum can, wrinkles (cracks) and cracks are more likely to occur during neck processing. Become.

[0006] As such a bottle can, the body and the bottom are mainly formed of different members. A three-piece bottle can (including a screw cap; hereinafter referred to as a three-piece bottle can) and a two-piece bottle can (including a screw cap). 2 piece bottle cans).

[0007] Of these, the three-piece bottle can is generally manufactured by applying a part of the conventional two-piece aluminum can manufacturing method. That is, as disclosed in Patent Document 1 and Patent Document 2 described later, first, cutting and DI molding, baking, trimming, printing, baking, and necking (top molding: neck force) are performed on a predetermined aluminum plate. Sequentially applied. In the neck processing, a neck portion is formed on the bottom side portion of the body portion, and then an end portion of the neck portion is opened to provide a mouth portion. The outer periphery in the vicinity of the mouth portion is threaded for screw cap attachment to form a screw portion. After that, the flange portion is formed on one of the opening portions of the body portion facing the mouth portion as a bottom portion, and then the bottom portion is tightened to form the bottom portion.

[0008] In such a three-piece bottle can, since the neck portion is formed at the bottom of the can after DI molding at the time of neck processing, even if the drawing ratio of the diameter of the neck portion to the diameter of the body portion is large, It can be formed relatively easily.

On the other hand, from the viewpoints of manufacturing cost reduction and recyclability of bottle cans, in recent years, the need for two-piece bottle cans has gradually increased in place of the above-described three-piece bottle cans. In this two-piece bottle can, in general, many of the conventional methods for producing a two-piece aluminum can are applied, and in particular, neck processing such as die-neck and spin-neck cases is used as it is.

[0010] As disclosed in Patent Document 1 and Patent Document 2, which will be described later, the manufacturing method of the two-piece bottle can first includes a cutting on a predetermined aluminum plate A to form a body portion of the bottle can. DI molding is performed to form the body and bottom. Next, a neck neck or spin neck force check is applied in the vicinity of the opening of the body to form a neck, and the opening is used as a mouth. Thereafter, a screw cutting portion for attaching a screw cap is provided on the outer periphery in the vicinity of the mouth portion, whereby a two-piece bottle can is manufactured.

[0011] However, in this two-piece bottle can, when the neck portion is formed, the neck portion is formed by performing die neck processing or spin neck processing in the vicinity of the opening portion of the body portion. It is difficult to configure with a large aperture ratio of mouth diameter to part diameter. I

[0012] When forming the neck portion of the two-piece bottle can using the above-described 3000 series aluminum alloy hard plate, the mouth portion with respect to the diameter of the body portion is formed by the relatively hard rigidity of the aluminum plate. When a bottle can was formed by increasing the diameter reduction ratio, wrinkles and cracks were likely to occur. Therefore, it has been difficult to form the drawing ratio of the conventional two-piece bottle can with the drawing ratio of the three-piece bottle can.

[0013] In response to the problem of this two-piece bottle can, the content of Fe, Si, Mn, and Mg in the 3000 series aluminum alloy sheet and the resistance against baking (0.2% )) To an appropriate range, the formability of the aluminum plate, that is, the formability of DI molding, neck processing, etc., is improved. As a result, the aperture ratio of the diameter of the mouth to the diameter of the body is increased. It has been proposed to do so (see Patent Document 1).

[0014] Similarly, the content of Fe, Si, Mn, Mg and Cu and the anti-bake strength (0.2% resistance) after baking in the 3000 series aluminum alloy sheet should be regulated within an appropriate range. Therefore, it has been proposed to improve the formability of the aluminum plate, that is, the formability of DI molding, neck processing, etc., and as a result, increase the ratio of the diameter of the mouth portion to the diameter of the body portion. (See Patent Document 2).

In addition to this, many proposals have been made to control the structure in order to improve the moldability of cans. For example, the Mn solid solution amount and crystal grain size of the hot-rolled sheet are controlled within a predetermined range, and the ear ratio of the hot-rolled sheet is stabilized to −3 to −6%, which is then subjected to intermediate annealing. It has also been proposed that the cold-rolled sheet obtained by cold rolling is made to have an ear rate of 0 to 2% stably (Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2002-256366

Patent Document 2: JP 2004-250790 A

Patent Document 3: Japanese Patent Laid-Open No. 2003-342657

Disclosure of the invention

Problems to be solved by the invention

[0016] However, these two-piece bottle cans tend to be smaller and smaller in diameter in recent years, such as mini bottle cans. In 2-piece bottle cans such as mini bottle cans, in particular, retort processing There is an increasing demand for improving the sealing performance after tightening the cap in the case of contents to be processed. Along with this, the force that increases the tightening load of the cap tends to require strength of the can body that can withstand the increase of the tightening load. For this reason, higher strength is also required on the can material side.

[0017] However, when the strength of the can material side is increased only by the components in the conventional 3000 series aluminum alloy sheet and the resistance adjustment after baking, the neck portion is formed by neck processing or spin neck cage. Then, wrinkles (cracks) and cracks tend to occur more easily when the threaded part for screw cap attachment is formed on the outer periphery near the mouth.

[0018] In addition, reductions in the amount of metal used and cost reduction such as light weight that are commonly required for cans are also required for two-piece bottle cans such as mini bottle cans, and from this aspect. The higher strength on the can material side is inevitable.

[0019] The present invention has been made in view of a serious problem, and an aluminum alloy cold-rolled sheet for a bottle can excellent in neck formability and thread formability even in a more miniaturized two-piece bottle can. And it aims at providing the manufacturing method of this cold rolled sheet.

Means for solving the problem

[0020] In order to achieve this object, the gist of the aluminum alloy cold-rolled sheet for bottle cans excellent in neck formability according to the present invention is as follows: Mn: 0.7 to 1.5% (mass ⁰ / ₀ , the same shall apply hereinafter), Mg: _{0.8 to} 1.7%, Fe: 0.1 to 0.7%, Si: 0.05 to 0.5%, Cu: 0.1 to 0.6% contains, has with balance of forces Alpha 1 and unavoidable impurities, and, the dispersed particles mosquito ^ 300 111 ² per Saizu of 0.05 to 1 111 observed by from 5,000 to 15,000 times the ΤΕΜ tissue Among these dispersed particles, the number ratio of dispersed particles having a size of 0.3 m or more is within a range of 15 to 70% with respect to the total number of dispersed particles. It is assumed that

[0021] In order to achieve this object, the gist of the manufacturing method of the aluminum alloy cold-rolled sheet for bottle cans excellent in neck part moldability of the present invention is the above gist or a preferred embodiment of an aluminum alloy described later. When obtaining a cold-rolled sheet, the ingot is homogenized at a temperature of 550 ° C or higher and then gradually cooled to a temperature range of 450 to 550 ° C at a cooling rate of 25 ° C Zhr or less. In addition, 50 to 400 dispersed particles having a size of 0.05 to 1 μm are observed per 300 / zm ² as observed by TEM 5000 to 15000 times the plate structure after cold rolling. The number ratio of the dispersed particles having a size of 0.3 m or more in the dispersed particles is to be in the range of 15 to 70% with respect to the total number of dispersed particles.

The invention's effect

[0022] As described above, the DI can body of the bottle can is required to be further thinned mainly for the purpose of reducing the manufacturing cost and reducing the weight. In order to achieve this reduction in thickness, it is necessary to increase the strength of the aluminum alloy cold-rolled sheet as a material so as not to lower the buckling strength. In order to achieve thinning, it is also strongly required that the ear rate during DI molding is low. If the ear rate during DI molding is lowered, the yield during DI molding can be increased, and furthermore, the can body can be prevented from being broken due to the cutting out of the can body.

[0023] For this reason, as described above, it is conventionally known to control the structure of an aluminum alloy cold-rolled sheet, which is a DI can body material of a bottle can, in order to highly stabilize the ear rate. Typical examples include control of crystal grain refinement, control of the number and size of compounds such as Mg Si, and addition.

2

These include suppression of micro-segregation of additive elements, solid solution control of alloy elements such as Mn, and control of cube orientation.

[0024] Also in the present invention, dispersed particles (such as Mg Si) present in the aluminum alloy cold-rolled sheet structure are used.

In terms of controlling the number and size of 2 compounds and precipitates), these conventional metallurgical controls are followed.

[0025] However, in the present invention, in contrast to these conventional fine dispersion ideas in which the dispersed particles are dispersed as finely as possible, the dispersed particles are coarsened to some extent, and then the sizes are made uniform. , Make a certain amount (a certain number).

[0026] That is, the inventors of the present invention, when the dispersed particles are coarsened to some extent and the size is made uniform, the pinning effect of the dispersed particles is less than that of the conventional fine dispersion, and hot rolling is performed. On the contrary, it was found that uniform and isotropic crystal grains (without directionality or anisotropy) were obtained and the ear rate was improved in the plate state.

[0027] On the other hand, when the dispersed particles are finely dispersed as in the past, the pinning effect of the dispersed particles is In hot rolling where the fruits are strong, the original soft PFZ force is easily recrystallized, and accordingly, the precipitation zone is also recrystallized to form coarse grains. In addition, the cube orientation is likely to develop. Therefore, as usual, when the dispersed particles are finely dispersed, the average grain size of the crystal grains is small, but coarse recrystallized grains are mixed in part, so-called so-called mixed grains. And isotropic properties are easily lost.

[0028] As a result, in the two-piece bottle can that has a reduced ear rate and is further reduced in size, the neck portion formed by the die neck or spin neck cache in the vicinity of the opening of the body portion described above, and the mouth portion thereafter Wrinkles (cracks) and cracks are more likely to occur when forming a threaded part for screw cap attachment on the outer periphery in the vicinity of.

On the other hand, in the present invention, the dispersed particles are coarsened to a certain extent, and the size is made uniform, and a certain amount is present, and is uniform and isotropic in the state of the hot-rolled sheet (direction or anisotropic). Without crystallinity), obtain crystal grains and improve the ear rate of the subsequent cold-rolled sheet.

Brief Description of Drawings

[0029] FIG. 1 is a drawing-substituting photograph showing the presence of dispersed particles of an aluminum alloy of the present invention (Invention Example 1).

FIG. 2 is a drawing-substituting photograph showing the presence of dispersed particles of the aluminum alloy of the present invention (Invention Example 2).

FIG. 3 is a development view of a cup obtained by DI molding a plate material.

BEST MODE FOR CARRYING OUT THE INVENTION

[0030] (A1 alloy cold-rolled sheet composition)

First, regarding the preferable chemical component composition (unit: mass%) that satisfies the various properties such as strength and formability necessary for the material for the two-piece bottle can of the A1 alloy cold-rolled sheet of the present invention, the reasons for limiting each element are as follows. Including, will be described below.

[0031] The composition of the aluminum alloy cold-rolled sheet for bottle cans excellent in high-temperature characteristics of the present invention is Mn: 0

7 to 1.5%, Mg: 0.8 to 1.7%, Fe: 0.1 to 0.7%, Si: 0.05 to 0.5%, Cu: 0.1

The composition contains ˜0.6%, the balance being A1 and inevitable impurity power.

[0032] Mn: 0.7 to 1.5%.

Mn is an effective element that contributes to improvement in strength and further contributes to improvement in formability. The In particular, in the two-piece bottle can material (cold rolled plate) as in the present invention, Mn is extremely important because the ironing, neck force, threading, and the like described above are performed during DI molding. It becomes.

In more detail, Mn forms various Mn-based intermetallic compounds such as A1-Fe-Mn-Si-based intermetallic phase. And, as the α phase is appropriately distributed, the formability or strength workability during each of the above processes can be improved. Also, in the ironing of aluminum plates, the power that emulsion type lubricants are usually used If the amount of α phase is small, the lubricity is insufficient even when emulsion type lubricants are used. There is a risk of appearance defects such as scuffing and seizure. Therefore, Mn is an indispensable element for generating α phase and preventing surface flaws during ironing.

[0034] If the Mn content is too small, the above-described moldability or workability improvement effect cannot be exhibited.

For this reason, the Mn content is 0.7% or more, preferably 0.8% or more, preferably 0.85% or more, and more preferably 0.9% or more.

On the other hand, when Mn is excessive, the primary crystal giant metal compound of Mn and A1 is crystallized, and the moldability is lowered. Therefore, the upper limit of the Mn content is 1.5%, preferably 1.3%, more preferably 1.1%, and even more preferably 1.0%.

[0036] Mg: 0.8 to 1.7%.

Mg is effective in that the strength can be improved. Furthermore, by including it together with Cu, which will be described later, the cold rolled sheet of the present invention is finally annealed (also called finish annealing. For example, temperature: about 100 to 150 ° C, time: annealing for about 1 to 2 hours), Subsequent canning and soft baking can be suppressed when force baking (baking printing). That is, when both Mg and Cu are contained, Al—Cu—Mg precipitates during baking (baking printing), and thus softness during baking can be suppressed.

[0037] If the Mg content is too small, the above effects cannot be exhibited. Therefore, the Mg content is 0.8% or more, preferably 0.9% or more, and more preferably 1.0% or more.

[0038] On the other hand, if Mg is excessive, work hardening is likely to occur, and formability is reduced. Therefore, the upper limit of the Mg content is 1.7%, preferably 1.6%, and more preferably 1.35%. [0039] Mg also affects the amount of Mn deposited and dissolved. In other words, as the amount of Mg increases, the amount of precipitation of the A1-Fe-Mn-Si intermetallic compound phase) is suppressed, and the amount of Mn solid solution tends to increase. For this reason, it is preferable to determine the Mg content in relation to the Mn solid solution amount.

[0040] Fe: 0.1 to 0.7%.

Fe has the effect of refining crystal grains, and further generates the above-mentioned A1-Fe-Mn-Si intermetallic compound (α phase), which contributes to the improvement of moldability. Fe is also useful in that it promotes Mn crystallization and precipitation and controls the amount of Mn solid solution in the aluminum matrix and the dispersion state of Mn-based intermetallic compounds. On the other hand, if Fe is excessive in the presence of Mn, a large primary intermetallic compound is likely to be generated, which may impair the moldability.

[0041] Therefore, the Fe content can be set according to the Mn content, and the preferred mass ratio (FeZMn) of Fe and Mn is, for example, in the range of 0.1 to 0.7, preferably It is in the range of 0.2 to 0.6, and more preferably in the range of 0.3 to 0.5.

[0042] When the Mn content is in the above range, the lower limit Fe content is 0.1% or more, preferably 0.2% or more, and more preferably 0.3% or more. Further, the upper limit content of Fe is 0.7% or less, preferably 0.6% or less, and more preferably 0.5% or less.

[0043] Si: 0.05-0.5%.

Si consists of Mg Si intermetallic compounds and A1-Fe-Mn-Si intermetallic compounds (hyperphase).

2

It is an element useful for generating dust particles. As these dispersed particles are distributed to the appropriateness specified in the present invention, the moldability can be improved.

[0044] Therefore, the Si content is 0.05% or more, preferably 0.1% or more, and more preferably 0.

2% or more. On the other hand, when Si is excessive, recrystallization during hot finish rolling is hindered.

° Ear increases and moldability decreases. For this reason, the upper limit of the Si content is 0.5%, preferably 0.45%, more preferably 0.4%.

[0045] Cu: 0.1 to 0.6%.

When Cu is baked (baked and printed) when making cold-rolled sheets, Al—Cu—Mg precipitates, and soft inclusions can be suppressed by containing it together with Mg. For this reason

The lower limit of Cu content is 0.1% or more, preferably 0.15% or more, more preferably 0.2%. That's it. On the other hand, if Cu is excessive, age hardening can be easily obtained, but it becomes too hard, so that formability is reduced and corrosion resistance is also deteriorated. Therefore, the upper limit of Cu content is 0.6%, preferably 0.5%, more preferably 0.35%.

[0046] In addition to Cu, examples of the strength improving element having the same effect include Cr and Zn. In this respect, in addition to Cu, one or two of Cr and Zn can be selectively contained.

[0047] Cr: 0.001 to 0.3%.

At this time, the Cr content is 0.001% or more, preferably 0.002% or more, in order to exert the strength improvement effect. On the other hand, when Cr is excessive, giant crystals are formed and formability is lowered. For this reason, the upper limit of the Cr content is 0.3%, preferably 0.25%.

[0048] Zn: 0.05-: L. 0%.

In addition, when Zn is contained, the strength can be improved by aging precipitation of Al—Mg—Zn-based particles. In order to exert this effect, the Zn content is 0.05% or more, preferably 0.06% or more. On the other hand, when Zn is excessive, the corrosion resistance decreases. Therefore, the upper limit for the Zn content is 0.5%, preferably 0.45%.

[0049] Ti: 0.005 to 0.2%.

Ti is a grain refinement element. This effect was demonstrated! / Sometimes it is contained selectively. In this case, the Ti content is 0.005% or more, preferably 0.01% or more, and more preferably 0.015% or more. If Ti is excessive, a huge A1-Ti intermetallic compound crystallizes and hinders formability. Therefore, the upper limit of Ti content is 0.2%, preferably 0.1%, more preferably 0.05%.

[0050] The Ti may be contained alone, but may be contained together with a small amount of B. When used in combination with B, the effect of crystal grain refinement is further improved. For this reason, the B content when selectively contained is 0.0001% or more, preferably 0.0005% or more, and more preferably 0.0008% or more. On the other hand, if B is excessive, Ti-B coarse particles are formed, which lowers the moldability. Therefore, the upper limit of the B content is 0.05%, preferably 0.01%, and more preferably 0.005%.

[0051] The elements other than those described above are unavoidable impurities, and in order not to inhibit the above-mentioned plate characteristics, the content should be basically low. The inclusion of up to the upper limit of each element of 3000 series aluminum alloy is permitted.

[0052] (Dispersed particles)

Next, the A1 alloy cold rolled sheet structure of the present invention will be described below.

As described above, in the present invention, dispersed particles [intermetallic compounds such as Mg Si, Al—Fe—Mn—Si (hyperphase), precipitates] present in the aluminum alloy cold rolled sheet structure are roughened to some extent.

2

After increasing the size, the size is made uniform and a certain amount (a certain number) is present. As a result, the pinning effect of the dispersed particles is alleviated, and uniform and isotropic crystal grains (not having directionality or anisotropy) are obtained in the hot-rolled sheet state, and the ear ratio is improved.

[0053] More specifically, 50 to 400 pieces of the dispersed particles of Saizu of 0.05 to 1 111 observed by 5000-15000 fold TEM of an aluminum alloy cold-rolled sheet tissues (centroid diameter) 300 111 ² per Make it exist. Of these dispersed particles, the ratio of the number of dispersed particles having a size of 0.3 m or more is set to a range of 15 to 70% with respect to the total number of dispersed particles. At this time, the lower limit of the number ratio of the dispersed particles having the above size is preferably 20% or more, more preferably 25% or more, and the range is 20 to 70%, and further 25 to 70%. And is preferred.

[0054] Figs. 1 and 2 show 10000-fold TEM photographs of the cold rolled sheet structure of the aluminum alloy of the present invention. In Figs. 1 and 2, the dispersed black particles (compounds such as Mg Si and precipitates) are dispersed particles against the white matrix. Figure 1 shows the results of Table 3 in the examples described later.

2

Example 1 and FIG. 2 are Example 2.

[0055] In this comparison between Figs. 1 and 2, in both Figs. 1 and 2, there are 50-400 dispersed particles per 300 µm ^{2 with} a size of 0.05 µm at the minimum and 1 µm at the maximum. Is the same. However, in FIG. 1, each dispersed particle is relatively coarsened and uniformly dispersed as compared to FIG.

[0056] The dispersed particles of the structure of the present invention in FIG. 1 have a larger number ratio of relatively coarse dispersed particles having a size of 0.3 m to 1 μm with respect to the total number of the dispersed particles. It has been. That is, the number ratio of the relatively coarse dispersed particles is 48% with respect to the total number of dispersed particles. That is, dispersed particles having a relatively large size and uniform size Can be said to be uniformly dispersed.

On the other hand, in the yarn and weaving of the present invention shown in FIG. 2, the number ratio of relatively coarse dispersed particles having a size of 0.3 m or more and 1 μm or less is the total number of dispersed particles. 20% of the existing number. That is, it can be said that dispersed particles of various sizes, such as the number ratio of relatively small dispersed particles, the small size force, and the large size are dispersed.

[0058] Dispersion particles having a size of 0.3 m or more when the number ratio of the relatively small dispersion particles is larger than that of the structure of the present invention in Fig. 2 or dispersion particles of various sizes are dispersed. When the ratio of the number of particles is less than 15% of the total number of dispersed particles, it becomes the same as conventional fine dispersion of dispersed particles. As a result, in hot rolling, the original soft PFZ force is easily recrystallized, and accordingly, the precipitation zone is also recrystallized to form coarse crystal grains. In addition, the cube orientation also tends to develop. Therefore, as in the conventional case, although the average grain size of the crystal grains is small, so-called so-called mixed grains in which coarse recrystallized grains are mixed in part, and the uniformity and isotropy of the crystal grains are lost. Easy!

[0059] For this reason, in the two-piece bottle can with a reduced ear rate and a more compact size, the neck portion formed by the die neck or spin neck cache in the vicinity of the opening of the body portion described above, and the mouth portion thereafter Wrinkles (cracks) and cracks are more likely to occur when forming a threaded part for screw cap attachment on the outer periphery in the vicinity of.

[0060] On the other hand, in the present invention, as described above, after the dispersed particles are coarsened to some extent, a certain amount (a certain number) is present and is uniform and isotropic in the state of the hot-rolled sheet ( Without crystallographic anisotropy), obtain crystal grains and improve the ear ratio of the subsequent cold-rolled sheet.

[0061] Here, the dispersed particles to be analyzed and measured have a size (center of gravity diameter) of 0.05 m or more as observed by a TEM of 5000 to 15000 times. This is because the presence of dispersed particles of 0.05 m or more greatly affects the moldability as described above, and the dispersed particles of less than 0.05 m have a small influence. In addition, small dispersed particles of less than 0.05 / zm are excluded from the scope of the present invention, because they are subject to large variations in measurement due to this measurement, which is difficult to observe and measure even with TEM.

[0062] (Measurement of particle size and number)

The particle size of the dispersed particles is determined with a transmission electron microscope (TEM) having a plate structure. More Specifically, the specimen at the center of the plate thickness and the upper surface of the rolled surface is mirror-polished, and the structure of the polished surface is 5000 to 15000 times TEM (for example, HF-2000 Field Emission Transmission Electron Microscope made by Hitachi Using a mirror, observe 10 fields of view with a size of about 10 / z mX about 15 m.

[0063] At this time, in order to clearly observe the dispersed particle phase (intermetallic compound phase), observation is performed by observing a reflected electron image. The white image is A1, and the dispersed particle phase becomes clear with different contrasts. Trace these dispersed particles, and use Image-ProPlus from MEDIACYBERNETI CS as image analysis software to determine the size of each dispersed particle (average value of the centroid diameter) by image analysis.

[0064] Then, the number of dispersed particles having a size of 0.05 to 1 μm is counted and converted to the number per 300 μm ² . Each measured number of dispersed particles was calculated as an average value in the observation of the 10 fields of view.

[0065] Further, among these dispersed particles having a size of 0.05 to 1 μm, the number of dispersed particles having a size of 0.3 m or more is set to the above-described dispersion of 0.05 to Lm. Similar to the number of particles. Then, the ratio (%) of the number of dispersed particles having a size of 0.3 / z m or more to the total number of dispersed particles having a size of 0.05 to 1 μm was determined.

[0066] (Average aspect ratio of crystal grains)

It is preferable that the crystal grains of the aluminum alloy cold-rolled sheet are elongated in the rolling direction with an average aspect ratio of 2 or more compared with ordinary equiaxed grains. As a result, there is an advantage that thermal deformation at the time of coating heat treatment can be suppressed and the strength of the can after heat treatment can be ensured with respect to high-speed heat treatment that has been shortened at a higher temperature. In other words, by making the crystal grains of the aluminum alloy cold-rolled sheet elongated in the rolling direction, ironing strength is imparted, and formability such as DI molding is secured, and then specified by the present invention. Thus, the strength of the can after heat treatment can be secured under the above-described component composition and the solid solution and precipitation state structure described later. This also suppresses thermal deformation during paint heat treatment.

[0067] When the average aspect ratio of the crystal grains is less than 2, it is not much different from normal equiaxed grains, and the above effects are insufficient, so it is not possible to suppress thermal deformation during coating heat treatment and to ensure the strength of the can after heat treatment. . In this respect, the larger the elongation in the rolling direction of the crystal grains, the better. The average aspect ratio of the crystal grains is preferably 2.1 or more. [0068] The aspect ratio of the crystal grains is determined by the crystal grain structure of the hot-rolled sheet and the cold rolling rate in the process without intermediate annealing. In this respect, the upper limit of the average aspect ratio of the crystal grains is determined by the capability limit of the manufacturing process for producing elongated grains such as hot rolling or cold rolling, but the level is about 4.

[0069] (Average aspect ratio measurement method)

The average external ratio of crystal grains is measured by upper surface observation (polarization observation) at the center in the thickness direction. After tempering (before bottle can molding), the center of the plate in the thickness direction and the upper surface of the rolled surface are subjected to mechanical polishing, electrolytic polishing, and anodizing treatment with Barker's solution, followed by polarization observation.

[0070] When the crystal grain structure is polarized and observed from the upper surface of the central portion in the plate thickness direction of the plate, a difference in black and white appears due to a difference in crystal orientation. In this observation, the maximum length in the rolling direction and the maximum length in the plate width direction of each crystal grain are measured for the crystal grains in the field where the contour can be clearly observed. Then, the (maximum length in the rolling direction) Z (maximum length in the plate width direction) of each individual crystal grain is calculated as the aspect ratio. X Using an optical microscope with a magnification of 100, the number of crystal grains to be measured is 100, and the average aspect ratio of the crystal grains is obtained from the average value of the aspect ratios of the crystal grains. The average crystal grain size can be obtained by averaging the maximum length in the rolling direction of the individual crystal grains with the 100 measured crystal grains.

[0071] (Production method)

The A1 alloy cold-rolled sheet of the present invention can be produced without greatly changing the conventional soaking, hot-rolling and cold-rolling production processes. However, the plate structure after hot rolling and cold rolling is the dispersed particle structure specified in the present invention, and the basic material properties (ear ratio, strength), formability, and ironing workability for bottle can molding In order to secure the mass without hindering, it is necessary to cool the lump at a cooling rate of 25 ° CZhr or less to a temperature range of 450 to 550 ° C after homogenization heat treatment at a temperature of 550 ° C or more. .

[0072] (Homogenization heat treatment conditions)

Homogeneous heat treatment (soaking) temperature is 550 ° C or higher, preferably 650 ° C or lower. If the soaking temperature is too low, too much time will be spent on homogeneity and productivity will be reduced, and if the soaking temperature is too high, the surface of the lump will swell, so set the soaking temperature in the above range. . More preferable average The heat temperature is 580 ° C or higher (especially 590 ° C or higher) and 615 ° C or lower (especially 610 ° C or lower).

[0073] The soaking time (homogenization time) is preferably as short as possible, for example, 6 hours or less, as long as the soot lump can be homogenized. In the present invention, as described later, it is necessary to gradually cool after soaking, and it takes time to cool after soaking. Therefore, soaking time is as short as possible to improve the efficiency of soaking process.

[0074] (Cooling conditions after soaking)

As described above, in order to make the plate structure after hot rolling and cold rolling into a dispersed particle structure stipulated in the present invention and to secure basic material characteristics for bottle can molding, After soaking under the above conditions, it is necessary to gradually cool to a temperature range of 450 to 550 ° C at a cooling rate of 25 ° C Zhr or less. In order to perform such slow cooling, it is preferable to cool the soaked lump in the soaking furnace.

[0075] In the case of cooling the soaked soot out of the soaking furnace or forced air cooling with a fan, the cooling rate after the soaking treatment inevitably exceeds the upper limit of 25 ° CZhr. For this reason, the dispersed particle structure defined in the present invention is not obtained, and dispersed particles having a relatively small number of dispersed particles or a particle having various sizes are dispersed as compared with the structure of the present invention shown in FIG. Thus, the number ratio of dispersed particles having a size of 0.3 m or more is less than 15% with respect to the total number of dispersed particles. For this reason, it becomes the same as the conventional fine dispersion of dispersed particles.

[0076] The soaking process may be performed in a plurality of stages, but at least the cooling rate after the final soaking process is slow cooling like the above cooling rate.

[0077] (Conditions for hot rolling)

Handling of the ingot after completion of the soaking may be performed by hot and rough rolling after cooling and reheating, or by hot rough rolling without cooling excessively. However, even in this case, the cooling rate from the soaking process to the hot rough rolling start temperature should be slow cooling like the above cooling rate.

[0078] (Hot rough rolling conditions)

When hot rolling is divided into rough rolling and finish rolling and performed continuously, if the end temperature of hot rough rolling is too low, the rolling temperature will be lowered by hot finish rolling in the next process. Edge cracks are likely to occur. If the end temperature of hot rough rolling is too low, Unrecrystallized residue due to insufficient self-heating during rolling, or surface quality decreases due to increased rolling load. For this reason, the end temperature of hot rough rolling is preferably set to 420 ° C or higher. Further preferable end temperatures are 430 ° C or higher (especially 440 ° C or higher) and 470 ° C or lower (especially 460 ° C or lower).

[0079] In order to keep the end temperature of the hot rough rolling at about 420 to 480 ° C, the start temperature of the hot rough rolling is, for example, about 490 to 550 ° C, preferably 495 to 540 ° C. It is desirable that the temperature be about 500 to 530 ° C. If the starting temperature is set to 550 ° C. or lower, surface oxidation of the hot rolled sheet can be prevented. Furthermore, since the coarsening of recrystallized grains can be prevented, the moldability can be further improved.

[0080] The aluminum alloy sheet that has been subjected to the hot rough rolling is desirably subjected to hot finish rolling as quickly as possible. By rapidly performing hot finish rolling, it is possible to prevent recovery of strain accumulated in hot rough rolling, and it is possible to increase the strength of the cold-rolled sheet obtained thereafter. The aluminum alloy sheet that has been subjected to hot rough rolling is preferably hot-rolled within 5 minutes, preferably within 3 minutes, for example.

[0081] (Hot finish rolling conditions)

The finishing temperature of hot finish rolling is preferably 310 to 350 ° C. The hot finish rolling process is a process of finishing a sheet to a predetermined size. Since the structure after rolling is recrystallized by self-heating, the end temperature affects the recrystallized structure. Hot finishing By setting the end temperature of rolling to 310 ° C or higher, the final sheet structure is screened with a structure in which the average aspect ratio is 3 or more and stretched along with the subsequent cold rolling conditions. If the finishing temperature of hot finish rolling is less than 310 ° C, the average aspect ratio is unlikely to increase even if the cold rolling rate of the subsequent cold rolling is increased.

[0082] On the other hand, when the temperature exceeds 350 ° C, the final plate structure becomes a structure stretched in the rolling direction with an average aspect ratio of 3 or more, and coarse Mg Si or the like precipitates, and the dispersed particles defined in the present invention Pair

2

As a weaving. Therefore, the lower limit of the finish temperature of hot finish rolling is 310 ° C or higher, preferably 320 ° C or higher. The upper limit is 350 ° C or lower, preferably 340 ° C or lower.

[0083] (Type of hot finishing mill)

Use a tandem hot rolling mill with 3 or more stands as the hot finishing mill. . By setting the number of stands to 3 or more, the rolling rate per stand can be reduced, and strain can be accumulated while maintaining the surface properties of the hot-rolled sheet. Therefore, the strength of the cold-rolled sheet and its DI compact can be increased. It can be further increased.

[0084] (Total rolling ratio of hot finish rolling)

The total rolling reduction of hot finish rolling is desirably 80% or more. When the total rolling rate is 80% or more, in combination with cold rolling, which will be described later, the final sheet structure is a structure that is elongated in the rolling direction with an average aspect ratio of S3 or more, and the dispersed particles defined in the present invention. Easy to organize. In addition, the strength of the cold rolled sheet and its DI compact can be increased.

[0085] (Hot rolled sheet thickness)

The thickness of the alloy sheet after hot (finishing) rolling is preferably about 1.8 to 3 mm. By setting the plate thickness to 1.8 mm or more, it is possible to prevent the surface properties (seizure, rough skin, etc.) of the hot rolled plate and the plate thickness profile from being damaged. On the other hand, by setting the plate thickness to 3 mm or less, it is possible to prevent the rolling rate from becoming too high when manufacturing cold rolled plates (usually, plate thickness: about 0.28 to 0.35 mm). Can reduce the ear rate.

[0086] (Cold rolling)

In the cold rolling process, it is desirable to perform so-called straight through rolling with a plurality of passes without intermediate annealing, so that the total rolling ratio is 77 to 90%. By setting the total rolling rate without intermediate annealing to 77% or more, the final plate structure is a structure in which the average aspect ratio of the crystal grains is elongated in the rolling direction and the dispersed particles defined in the present invention It can be an organization. In addition, the pressure resistance of the can can be further increased. When intermediate annealing is performed, or when the total rolling reduction is low, it is difficult to become equiaxed grains or to become elongated grains immediately.

[0087] On the other hand, if the rolling rate exceeds 90%, the average aspect ratio of the crystal grains can be increased, but the 45 ° ears during DI molding become too large and the strength becomes too strong. There is a high possibility of cutting and cracking at the bottom of the can.

[0088] The sheet thickness after cold rolling is about 0.28 to 0.35 mm in terms of forming into a bottle can.

[0089] In the cold rolling process, it is desirable to use a tandem rolling machine in which two or more rolling stands are arranged in series. By using such a tandem rolling mill, a single rolling stand has a single stage and is repeatedly rolled (passed) to cold-roll to a predetermined thickness. Compared with a rolling mill, even with the same total cold rolling rate, the number of passes (passing plates) can be reduced, and the rolling rate per pass can be increased.

[0090] Therefore, it is easy to obtain a structure in which the final plate structure is elongated in the rolling direction where the average aspect ratio of crystal grains is 3 or more.

[0091] Further, as in the prior art, after cold rolling using a single rolling mill, sub-grains are generated by causing continuous recovery at a lower temperature than in the case where finish annealing is performed. be able to. However, the rolling mill is not limited to a tandem rolling mill as long as it can recover sufficiently by cold rolling and sufficiently generate subgrains.

[0092] However, in cold rolling with a tandem rolling mill, the rolling rate in one pass plate is increased, and therefore the amount of heat generated in one pass plate is increased. If this calorific value becomes too high, the particle size of the dispersed particles may become coarse.

[0093] For this reason, in cold rolling with a tandem rolling mill, when the temperature of the aluminum plate immediately after cold rolling in the cold rolling process rises most, the aluminum plate is forcibly cooled, and the aluminum after cold rolling It is preferable that the temperature of the plate does not rise above 200 ° C.

[0094] As a means for forcibly cooling the aluminum plate during such cold rolling, normally used rolling oil that does not contain water is changed to an emulsion type such as water-soluble oil or water-soluble lubricant. Instead, it is preferable to use this aqueous emulsion and enhance the cooling performance without deteriorating the lubricating performance.

[0095] After cold rolling, if necessary, finish annealing (final annealing) may be performed at a temperature lower than the recrystallization temperature. Finish annealing recovers the work structure and improves DI moldability and can bottom moldability. The temperature of the finish annealing is preferably about 100 to 150 ° C, particularly about 115 to 150 ° C. By setting the temperature to 100 ° C or higher, the processed structure can be sufficiently recovered. On the other hand, by controlling the temperature to 150 ° C or less, excessive precipitation of solid solution elements can be prevented, and DI moldability and flange moldability can be further enhanced.

[0096] The finish annealing time is preferably 4 hours or less (particularly about 1 to 3 hours). By avoiding excessive annealing, excessive precipitation of solid solution elements can be prevented, and DI moldability can be further improved. Can be increased.

[0097] However, in the cold rolling by the tandem rolling mill described above, finish annealing is basically unnecessary because sub-grains can be generated at lower temperatures and continuously.

[0098] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples as well as the present invention, and is appropriately modified within a range that can meet the purpose described above and below. Of course, the present invention can be carried out in addition to the above, and they are all included in the technical scope of the present invention.

Example

[0099] In addition to aluminum ingots, can scraps and the like are used as melting raw materials, and the composition of components A to N shown in Table 1 below (invention examples: A to D, comparative examples: E to N) of the A1 alloy The molten metal was melted to produce a lump with a thickness of 600 mm and a width of 2100 mm by the DC forging method. In Table 1, the element content indicated by “1” is below the detection limit.

[0100] As shown in Table 1, in this ingot, the total amount of other elements in both the inventive example and the comparative example is unavoidable impurity elements, Zr, Bi, Sn, Ga, V, Co, Ni, Ca, Contain 0.03% or more of Mo, Be, Pb, W in the total content of these elements!

[0101] Soaking cakes of these component compositions were subjected to soaking treatment according to the conditions shown in Tables 2 and 4. Here, the rate of temperature increase in soaking is the rate of temperature increase from 300 ° C to the soaking temperature (maximum temperature). In addition, the cooling rate after the soaking is from the soaking temperature to a temperature range of 450 to 550 ° C (up to the starting temperature if the hot rough rolling starting temperature force is higher than 50 ° C). Show.

[0102] In all the inventive examples and the comparative examples, in the example where annealing is performed at a cooling rate of 25 ° C Zhr or less after soaking, the soaked soot is cooled in a soaking furnace. On the other hand, in the comparative example in which cooling is performed at a cooling rate exceeding 25 ° C Zhr after soaking, the soaking lump subjected to soaking is taken out of the soaking furnace.

[0103] After this soaking, as a hot rough rolling, a reverse hot rough rolling mill with one stand was used, and as a hot finish rolling mill, a tandem hot rolling mill with four stands was used. Then, hot rolling was performed. At that time, the time to start hot finish rolling after hot rough rolling is completed is 3 minutes. Within. In addition, an aluminum alloy hot-rolled sheet with a thickness of 2.5 mm after hot finish rolling was manufactured in common.

[0104] The obtained hot-rolled sheet was cold-rolled by a tandem rolling mill or a single rolling mill and commonly used to produce a plate material for a bottle can (cold-rolled sheet) having a final sheet thickness of 0.3 mm. Finish annealing (final annealing) after this cold rolling was not performed.

[0105] All the examples in Table 2 were performed on a tandem rolling mill with two roll stands without intermediate annealing.

Cold rolled with only one pass. In all of the examples in Table 4, the sheet was passed four times on a single rolling mill with a single roll stand, and the final annealing was performed at 150 ° C for 1 hour.

[0106] At this time, in cold rolling with a tandem rolling mill (all the examples in Table 2), aluminum immediately after cold rolling was used.

-The aluminum plate was forcibly cooled using an aqueous emulsion solution so that the temperature of the plate did not rise above 250 ° C.

[0107] A test piece was taken from the plate material (coil) for bottle can after cold rolling, and the structure of the test piece was measured as described above (however, the TEM magnification was 10,000 times). The number of dispersed particles having a size of πι (individual Ζ300 m ² ), the number ratio (%) of dispersed particles having a size of 0.3 / zm or more among these dispersed particles, and the average aspect ratio of crystal grains Each was investigated. These results are shown in Table 3 (continued from Table 2) and Table 5 (continued from Table 4).

[0108] (Mechanical properties)

The tensile strength and 0.2% resistance of the test piece were measured by a tensile test according to JIS Z 2201. Specimen shape It was prepared with ίO IS No. 5 specimen, and the specimen was prepared so that the longitudinal direction of the specimen coincided with the rolling direction. The crosshead speed was 5 mmZ and the test was performed at a constant speed until the test piece broke.

[0109] Further, as a high temperature characteristic of the test piece, the test piece was simulated at 200 ° C by simulating a can coating baking process.

X 0.2% resistance (ABO. 2% resistance) when heat-treated for 20 minutes, respectively, and compared with the 0.2% yield strength of the specimen at room temperature above, the decrease in yield strength after this heat treatment The amount (Δ resistance) was investigated. These results are also shown in Table 3 (continued from Table 2) and Table 5 (continued from Table 4).

[0110] Furthermore, as the formability that the bottle can plate material should basically satisfy, the ear rate and each formability required in each molding process of the two-piece bottle can were measured and evaluated. These results are also shown in Table 3. [0111] (Ear rate)

As for the ear rate, a blank was also collected from the plate material for the bottle can, and after applying a lubricant [DA Stuart, Nalco 6461], it was molded into a cup shape by a 40% deep drawing test using an Eriksen tester. investigated. The test conditions were blank diameter = 66.7 mm, punch diameter = 40 mm, die side shoulder radius 2. Omm, punch shoulder radius = 3 Omm, wrinkle pressure = 40 Okgf.

[0112] Eight directions of the opening edge of the cup obtained in this way (0 ° direction, 45 ° direction, 90 ° direction, 135 ° direction, 180 ° direction, 225 ° direction, 270 Measure the shape of the peaks and valleys that occur in the direction (° and 3 15 °) and calculate the average ear rate.

[0113] The method for calculating the average ear rate will be described with reference to FIG. Fig. 3 is a developed view of a cup obtained by DI molding a plate for a bottle can body. In this development, assuming the rolling direction as 0 °, the heights of the ears (Tl, T2, T3, T4; referred to as minus ears) occurring in the 0 °, 90 °, 180 °, and 270 ° directions were measured. Measure the height of the ears (Yl, Y2, Y3, Y4; called plus ears) that occur in the directions of °, 135 °, 225 °, and 315 °. The heights Y1 to Y4 and Tl to T4 are the heights from the bottom of the cup. From each measured value, the average ear rate is calculated based on the following formula.

Average Ear Rate (%) = [{(Y1 + Y2 + Y3 + Y4) (T1 + T2 + T3 + T4)} / {1/2 Χ (Υ 1 + Y2 + Y3 + Y4 + T1 + T2 + T3 + T4)}] X 100

[0114] In the cold rolled sheet that is the subject of the present invention, when the average ear rate is close to 0, four plus ears (Υ1 to Υ4) and two minus ears in 90 ° and 270 ° directions ( Although the development of Τ2 and Τ4) in Fig. 3 is suppressed, the development of two minus ears in the 0 ° and 180 ° directions (Tl in Fig. 3, Τ3) is difficult to suppress. If the absolute value of the average ear rate is simply reduced, for example, if the average ear rate is 2 to 2% (2% or less in absolute value), the average ear rate may be 2 or more and less than 0%. , And the negative ear (Tl, Τ3 in Fig. 3) is not sufficiently suppressed. When the average ear rate is 0-2% (positive side), the remaining two negative ears (Tl, Τ3 in Fig. 3) can be sufficiently suppressed. Therefore, it is possible to prevent the can body from being broken due to the ear cut. In the present invention, In this case, the allowable range was + 0% to + 3.5%.

[0115] (Silent formability)

The iron moldability of the plate material for bottle cans was evaluated. A blank with a diameter of 160 mm is punched from the plate material for the bottle can, a cup with a cup diameter of 92 mm is formed, and by redrawing, ironing, and trimming, the can can be made at a speed of 300 cans Z for bottle cans. A DI can body (inner diameter 66 m πι φ, height 170 mm, side wall plate thickness 115; ζ ΐη, side wall tip plate thickness 190 m, final third ironing rate 40%) was manufactured. The number of fractures (body cracks) per 50,000 cans was determined and the iron moldability was evaluated.

[0116] A 50,000-shaped formed can that did not break at all ◎ (very good), a breaking force that was less than or equal to ◯ (good), and a break that was 5 cans or more X (failed) ).

[0117] (Neck formability)

The neck formability of the plate material for bottle cans was evaluated. A neck part is formed by applying a die neck force to the vicinity of the opening of the above-mentioned DI can body for bottle cans (good product without breakage) formed for iron moldability evaluation. It was. The neck forming conditions were as follows: the outer diameter of the can body was 66.2 mm, the neck part was formed in four steps, and the uppermost neck outer diameter was 60.3 mm. The shape of wrinkles after neck processing per 10,000 cans was determined, and the neck formability was evaluated.

[0118] When forming a can of 100 cans, the occurrence of wrinkles in the neck portion was evaluated. If the occurrence of wrinkles was 0 to 1 can be evaluated as ○ (passed), and 2 or more cans as X (failed). evaluated.

[0119] (Screw formability)

The screw formability of the plate material for bottle cans was evaluated. A two-piece bottle can was manufactured by providing a threaded part for attaching a screw cap on the outer periphery near the mouth of the neck part (good product without wrinkles) of the molded can after the neck processing, and the screw moldability was evaluated. .

[0120] For the threaded part of the above-mentioned neck part formed can of 9000 cans, all the parts with good shape accuracy and no generation of partial shape defects were observed. Those that were below the can were rated as ◯ (good), and those with shape defects exceeding 2 cans were evaluated as X (non-conforming).

[0121] (Screw buckling strength)

The screw buckling strength is axial to the molded can (2-piece bottle can) molded up to the above threaded part. The compressive load in the direction was applied, and the load when the screw part buckled was measured with n (number of samples) = 10, and the average value was obtained. If this screw buckling strength is 1500N or more, there is no practical problem.

[0122] As is apparent from Tables 3 and 5, cold rolling was performed with a tandem rolling mill, and Invention Examples 1 to 5 in Table 3 and Invention Examples 20 to 24 in Table 5 had the composition of the present invention. The number of dispersed particles having a size of 05 to 1 μm and the ratio of the number of dispersed particles having a size of 0.3 m or more have a structure satisfying the provisions of the present invention.

As a result, Invention Examples 1 to 5 and 20 to 24 are excellent in ear rate. And it has excellent moldability required in each molding process of 2-piece bottle cans such as iron moldability, neck moldability, and screw moldability. In addition, the screw buckling strength is also excellent.

[0124] In particular, Invention Examples 1 to 5 in Table 3 are excellent in high-temperature characteristics in which the average aspect ratio of crystal grains is 3 or more and the resistance (strength) decrease after baking is small.

[0125] In contrast, Comparative Examples 6 to 9 in Table 3 and Comparative Examples 25 to 28 in Table 5 are within the composition range of the present invention, but the cooling rate after soaking is too high, Over 25 ° CZhr. Therefore, the dispersed particle structure does not become the dispersion particle structure defined in the present invention, and the dispersed particles having a size of not less than 0 when the number ratio of the small dispersed particles is large or dispersed particles of various sizes are dispersed. Is less than 15% of the total number of dispersed particles.

[0126] In Comparative Example 10 of Table 3, Mn is too high and a giant crystallized product is formed, which does not form the dispersed particle structure defined in the present invention. For this reason, it leads to frequent cracking at the time of bottle can molding. In Comparative Example 11, Mn is too low and the buckling strength is insufficient.

In Comparative Example 12, Mg is too high, and the deterioration of formability (particularly ironing workability) due to high work hardening is large.

In Comparative Example 13, Mg is too low and the buckling strength is insufficient.

In Comparative Example 14, Cu is too high and workability is reduced.

In Comparative Example 15, Cu is too low and the buckling strength is insufficient.

In Comparative Example 16, Si is too low and + ears are growing. In addition, the ironing ability is reduced due to the lack of α phase. In Comparative Example 17, Si is too high, and + ears due to remaining unrecrystallized crystals are growing. In addition, the caloric property is decreasing.

In Comparative Example 18, Fe is too low and unrecrystallized remains. In addition, if the amount of crystallized material is small, the ironing ability is lowered.

In Comparative Example 19, Fe is too high and + ears are growing. In addition, the amount of crystallized material increases too much, and the ironing workability deteriorates due to the promotion of crack propagation during processing.

[0127] As a result, these comparative examples have inferior ear ratios, and each formability and screw buckling strength required in each molding process of 2-piece bottle cans such as iron formability, neck formability, and screw formability. Is also inferior.

[0128] Comparative Examples 10 to 19 in Table 3 are produced under the preferred production conditions with a cooling rate after soaking. However, the alloy composition deviates from the composition of the present invention. For this reason, even if the dispersed particle structure force defined in the present invention is not included, or even if the dispersed particle structure is defined in the present invention, each forming process of a two-piece bottle can such as iron formability, neck formability, screw formability, etc. Each formability required in is poor. Also, the screw buckling strength and high temperature characteristics are inferior.

[0129] From the above results, the critical significance of each requirement of the present invention can be understood.

[0130] [Table 1]

Chemical composition of Al alloy (quality, but B is ppm, balance Ai)

Min

Si Fe Cu Mn Mg Cr Zn Βι ■ Β * Total amount of other elements A 0.25 0.44 0,21 0.88 0.88 ― ― ― ― 0.03 Bright 0.26 0.43 0.20 0.91 1, 05 0, 03 0.19 0.03 0 0.03 Example C 0.25 0.42 0 , 2 0.9 0.9 0.03 0.2 0.02 10 0, 04

D 0,3 0.45 0, I 1.3 1 ― ― 0.02 10 0.05

E 0.4 0.5 0.4 1.6 1 ― 0.01 40 0.04

F 0.2 0.4 0.2 0.6 1 ― 0.01 40 0.04 Ratio G 0.1 0.2 0: 3 1 1.8 0.03 30 0.03

H 0, 1 0,2 0.2 1 0.7 ― 0.03 30 0.03 Comparison I 0.3 0.4 0.7 1.1 0.9 ― 0.02 30 0.03

J 0.1.2 0.45 0.03 1.05 0.97 ― ― 0.02 30 0.03 Example κ 0.03 0.5 0.4 0.9 1 ― ― 0.03 30 0.03

L 0.6 0.4 0.4 0, 95 1,05 ― ― 0.03 30 0.03

M 0.3 0.05 1.2 1.1 ― ■ ― 0.02 30 0.03

N 0.2 0.8 0.33 0.99 L2 ― ― 0, 02 30 0.03

* Other elements: Zr, Bi, Sn, Ga, V, Co, Ni, Ca, Mo, Be, Pb, W total 2]

Soaking ¾¾ Reason Hot saturation rolling Hot finish rolling Cold rolling Minute soaking Cooling finished Thickness Rolling mill Cold rolling type

. c. C / hr. C%

[] 0132

23 610 2 14 504 461 92 341 2. 5 Tante 86 610 6 22 511 442 92 335 2. 5 Tantem 86 Description 24 610 4 15 501 451 921 321 2.5 Tantem 86 Abbreviation 22 610 4 512 469 92 332 2.5 Tantem 86 Example 23 610

¾ Table alloy abbreviation 4 14 549 483 92 340 2. 5 Tante, 'M 86

6 A P speed ascending 610 40 502 459 92 342 2. 5 Tantem 86

7 B 444 444 22244/233 ° C 929 0020 453 7111 610 39 505 453 92 321 2.5 5 Tam 86 Ratio 8 C Γ 610 35 514 471 92 333 2.5 5 Tante ', Mu 86

9 D 610 28 548 480 339 2.5 5 items 86

10 610 15 503 462 342 2. 5 Tantem 86

11 610 14 489 443 335 Tam 86

610 14 477 441 334 2. 5 Tantem 86 Holding time h

13 H 610 15 496 488 320 2.5 5 Tam 86 14 I 610 13 497 465 315 2.5 5 Tante ', Mu 86 15 J 610 13 474 459 92 326 2.5 5 Tantem 86 Example 16 κ 610 14 505 468 92 304 2.5 5 Tam 86 17 610 14 P 4 Warm opening 83 442 92 321 2. 5 Tandem 86

610 14 492 Start 466 92 327 2. 5 Tam 86

19 610 14 496 471 92 324 2. 5 Tantem 86 degrees

Total H%

Addition rate 9 99999

222 222

[

]

Industrial applicability

As described above, the present invention can provide an aluminum alloy cold-rolled sheet for bottle cans having excellent neck part formability and thread formability. Therefore, it is suitable for severe and required characteristic applications such as a more compact two-piece bottle can that is excellent in formability and is required to have no strength reduction even when heat-treated with a thin wall.

Claims

The scope of the claims

[1] Mn: 0.7 to 1.5 mass%, Mg: 0.8 to 1.7 mass%, Fe: 0.1 to 0.7 mass%, Si: 0.00

Containing 05 to 0.5% by mass, Cu: 0.1 to 0.6% by mass, the balance having a yarn composed of A1 and inevitable impurities, and 5000 to 15000 times that of yarn and weaving There are 50 to 400 dispersed particles with a size of 0.05 to 1 μm observed by TEM of 300 μm ² per 300 μm ² , and among these dispersed particles, a size of 0.3 m or more is observed. An aluminum alloy cold-rolled sheet for bottle cans having excellent neck part formability, wherein the number ratio of dispersed particles is 15 to 70% of the total number of dispersed particles.

[2] The crystal grain structure of the cold-rolled sheet according to claim 1, wherein the crystal grain structure of the cold-rolled sheet is a structure stretched in a rolling direction in which an average aspect ratio of the crystal grains is 3 or more by observing the top surface in the thickness direction center portion. Aluminum alloy cold-rolled sheet for bottle cans with excellent neck formability.

[3] The aluminum alloy cold-rolled plate further comprises Cr: 0.001-0.3% by mass, Zn: 0.05--1.

The aluminum alloy cold-rolled sheet for bottle cans having excellent neck part formability according to claim 1 or 2, comprising one or two selected from 0% by mass.

[4] The aluminum alloy cold-rolled sheet further contains 0.0005-0. 2% by mass of Ti alone or in combination with 0.0001-0.05% by mass. Any force Aluminum alloy cold-rolled sheet for bottle cans with excellent neck formability as described in item 1.

[5] In obtaining the aluminum alloy cold-rolled sheet according to any one of claims 1 to 4, the ingot is homogenized at a temperature of 550 ° C or higher, and then to a temperature range of 450 to 550 ° C, 25 ° Slow cooling at a cooling rate of CZhr or less, observed by TEM 5000 to 15000 times the hot-rolled and cold-rolled sheet structure, 0.05 to 1 μm in size of dispersed particles per 300 μm ² In these dispersed particles, the proportion of the number of dispersed particles having a size of 0.3 m or more is 15 to 70% of the total number of dispersed particles. A method for producing an aluminum alloy cold-rolled sheet for bottle cans, which is excellent in formability of the neck part, characterized by being in a range.

[6] The aluminum alloy cold-rolled sheet for bottle cans with excellent neck formability according to claim 5, wherein the cold-rolling is cold-rolling to a final sheet thickness without annealing. Production method.