WO2017110869A1

WO2017110869A1 - Aluminum alloy sheet for can body, and method for manufacturing same

Info

Publication number: WO2017110869A1
Application number: PCT/JP2016/088086
Authority: WO
Inventors: 信吾岩村
Original assignee: 株式会社Uacj
Priority date: 2015-12-25
Filing date: 2016-12-21
Publication date: 2017-06-29
Also published as: CN108368570B; JPWO2017110869A1; CN108368570A; JP6898254B2; US20210292878A1; US20180282848A1

Abstract

Provided are an Al alloy sheet having excellent characteristics for use as a can body, and a method for manufacturing the Al alloy sheet. A sheet having an Al alloy comprising a predetermined alloy composition as the material thereof, wherein an Al alloy sheet for a can body is configured so that the solid solution Mn content thereof after hot rolling is 0.25 mass% or greater, the solid solution Fe content is 0.02 mass% or greater, and the solid solution Si content is 0.07 mass% or greater, the electrical conductivity thereof is 30.0-40.0% IACS, the tensile strength in the rolling direction of a cold-rolled sheet thereof is 280-320 MPa, the tensile strength in the rolling direction after heat treatment at 205°C for 10 minutes is 270-310 MPa, and the difference between the tensile strength in the rolling direction and the yield stress in the rolling direction after heat treatment at 205°C for 10 minutes is 50 MPa or less.

Description

Aluminum alloy plate for can body and manufacturing method thereof

The present invention relates to an aluminum alloy plate for a can body and a method for producing the same, and more particularly to an aluminum alloy plate capable of exhibiting excellent characteristics when producing a can body and an effective production method thereof.

Conventionally, aluminum (Al) alloy sheets for can bodies have been manufactured by subjecting an Al alloy ingot to homogenization, hot rolling and cold rolling, as is well known. And after degreasing and oiling etc. are given to the Al alloy plate for can body, if necessary, cup molding, DI molding, trimming, cleaning, drying, painting, baking, necking and flange processing A can body for beverages and the like is manufactured through such processes.

By the way, the can body for beverages or the like is required to have a can body strength that can withstand use, but in the above-described baking process after coating (hereinafter referred to as a coating baking process). The strength of the can body is greatly reduced. For this reason, various proposals have been made regarding the prevention of such a decrease in strength of the can body. For example, the following techniques have been clarified.

That is, Japanese Patent Laid-Open No. 2012-92431 (Patent Document 1) discloses an Al alloy cold-rolled sheet for bottle cans having a specific alloy composition and having a center-of-gravity diameter typified by α phase in the plate structure of 1 μm. In addition to reducing the number of dispersed particles below, the abundance ratio of the β phase, which is an Al ₆ (Fe, Mn) intermetallic compound, and the α phase, which is an Al—Fe—Mn—Si intermetallic compound, The maximum height of the X-ray diffraction peak of Hβ and the maximum height of the X-ray diffraction peak of the α phase: Hα: The ratio of Hβ / Hα is 0.50 or more. It has been clarified that by making the crystal ratio uniform, the variation in the ear ratio in the plate width direction can be reduced.

Japanese Patent Application Laid-Open No. 2011-202273 (Patent Document 2) is an Al alloy cold-rolled sheet for bottle cans having a specific alloy composition, and regulates the solid solution amount of Fe and Mn in the plate structure. By increasing the number density of relatively large dispersed particles that become nucleation sites for recrystallization in the hot-rolled sheet, the center side in the sheet width direction of the hot-rolled sheet, particularly at the center of the sheet thickness, is increased. It is disclosed that recrystallization is promoted, the recrystallization rate in the plate width direction of the hot-rolled plate is made uniform, and as a result, the variation in the ear rate in the plate width direction is reduced.

On the other hand, in recent years, from the viewpoint of environmental protection, in the production of a beverage can body, it has become an important issue to recycle a recycled lump of a used beverage can (UBC). Furthermore, in order to reduce the amount of material used, the can body is being made thinner and lighter. Since the UBC reclaimed lump is often mixed with Si, Fe, etc., when the UBC reclaimed lump is recycled, the resulting Al alloy ingot contains a high concentration of Si and Fe. It becomes. In that case, during the heat treatment of the Al alloy ingot, Si forms an intermetallic compound with Mn and Fe, resulting in a decrease in the Mn solid solution amount. As a result, the heat resistance softening property of the Al alloy plate is lowered, causing a problem that the reduction in the strength of the can in the coating baking process becomes more remarkable. Also, considering the strength reduction in the paint baking process, when the initial strength of the Al alloy plate is increased, the thickness of the can wall becomes thinner due to the thinner and lighter can body. There is a problem that is likely to occur. Therefore, in the case of manufacturing a beverage can body by recycling the recycled mass of UBC, it was necessary to limit the amount of use and add new bullion to adjust the Si content.

Patent Document 1 discloses that the generation of precipitated particles (α phase) of less than 1 μm is suppressed, and Patent Document 2 specifies only the solid solution amount of Fe and Mn, and heat It is disclosed that recrystallization during hot rolling is promoted and only the ear rate is controlled, but there is no compatibility between the strength of the can body and the ear rate, and the solidity of Fe, Mn, and Si is also disclosed. It did not pay attention to the amount of solution and the fine precipitate particles (α phase) during cold rolling.

JP 2012-92431 A JP 2011-202273 A

Here, the present invention has been made in the background of the circumstances as described above, and the problem to be solved is to provide an Al alloy plate having excellent characteristics for a can body and a method for producing the same. In particular, by optimizing the solid solution amount of Fe, Mn, Si in the cold rolled sheet of Al alloy and fine precipitate particles (α phase) during cold rolling, the strength of the can body is reduced. In particular, an object of the present invention is to provide an Al alloy plate for a can body and a method for producing the same that can effectively suppress a reduction in strength of the can after heat treatment that affects problems such as torso-cutting.

In the present invention, in order to solve the above-described problems, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, and Fe: 0.0. 25 to 0.6%, Si: 0.25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05 %, And the balance is a cold-rolled sheet obtained by using a hot-rolled sheet made of an Al alloy composed of Al and inevitable impurities, the solid material in the hot-rolled sheet. The amount of dissolved Mn is 0.25% by mass or more, the amount of dissolved Fe is 0.02% by mass or more, the amount of dissolved Si is 0.07% by mass or more, and the conductivity is 30.0 to 40.0% IACS. The cold-rolled sheet has a tensile strength (TS) in the rolling direction of 280 to 320 MPa, and is heat treated at 205 ° C. for 10 minutes. The tensile strength (ABTS) in the rolling direction is 270 to 310 MPa, and the difference between the tensile strength (TS) in the rolling direction and the yield strength (ABYS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 50 MPa. The gist of the present invention is an Al alloy plate for a can body characterized by the following.

In the present invention, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0 on a mass basis. 25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being Al. A hot-rolled sheet made of an aluminum alloy composed of inevitable impurities, a solid solution Mn amount of 0.25 mass% or more, a solid solution Fe amount of 0.02 mass% or more, and 0.07 mass% An aluminum alloy hot-rolled sheet for a can body, characterized in that it contains the above-mentioned solute Si amount and has a conductivity of 30.0 to 40.0% IACS. Is.

Further, in the present invention, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0 on a mass basis. 25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being Al. A plate material made of an aluminum alloy composed of inevitable impurities, the tensile strength (TS) in the rolling direction is 280 to 320 MPa, and the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes. Can body is characterized in that the difference between the tensile strength (TS) in the rolling direction and the yield strength (ABYS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 50 MPa or less. An aluminum alloy plate for use is also the gist thereof.

Note that the Al alloy plate for a can body according to the present invention advantageously has a conductivity of 28.4% IACS to 39.8% IACS.

And, in order to produce an Al alloy plate for a can body according to the present invention as described above, (a) based on mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B A step of preparing an aluminum alloy ingot containing 0.05% or less of aluminum alloy consisting of Al and inevitable impurities, and (b) hot rolling using the aluminum alloy ingot. The solid solution Mn content is 0.25% by mass or more, the solid solution Fe content is 0.02% by mass or more, the solid solution Si content is 0.07% by mass or more, and the conductivity is 30.0 to A step of obtaining a hot-rolled sheet material of 40.0% IACS, and (c) cold-rolling the hot-rolled sheet material, The tensile strength (TS) in the extending direction is 280 to 320 MPa, the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 270 to 310 MPa, and the tensile strength in the rolling direction ( A manufacturing method including a step of forming a cold-rolled sheet material in which a difference between TS) and a yield strength (ABYS) in a rolling direction after heat treatment at 205 ° C. for 10 minutes is 50 MPa or less is advantageously employed.

In the present invention, in order to advantageously produce the above-described Al alloy plate for can bodies, Mn: 0.7 to 1.3%, Mg: 0.8 to 1. 5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% And B: 0.05% or less, and after chamfering an Al alloy ingot made of an Al alloy consisting of Al and unavoidable impurities, 550 at a temperature rising rate of 30 to 120 ° C./hour. Homogenization by heating to a homogenization temperature (T) in the range of ˜620 ° C. and holding at the homogenization temperature (T) for not less than (145-0.24 T) hours And then immediately after completion of such homogenization or at a cooling rate of 10 to 90 ° C./hour. After cooling to a hot rolling start temperature that does not fall below 0 ° C., hot rough rolling is performed so that the delivery temperature is 430 to 550 ° C. to form a plate material with a plate thickness of 20 to 40 mm, Subsequently, hot finish rolling is performed so that the outlet temperature is 300 to 390 ° C. to obtain a plate material having a plate thickness of 1.5 to 4.0 mm, and the total workability is 75% or more and the final pass is steady. A method for producing an Al alloy plate for a can body, characterized in that cold rolling is performed so that the average rolling speed of the part is 700 to 1600 m / min, and the plate thickness is 0.2 to 1.0 mm, This is the gist.

In addition, in one of the preferable embodiments of the method for producing an Al alloy plate for a can body according to the present invention, the conductivity (S1) of the plate material obtained by the hot finish rolling and the cold rolling can be obtained. The difference (S1−S2) from the conductivity (S2) of the plate material to be obtained is adjusted to be 0.2 to 1.6% IACS.

In another preferred embodiment of the method for producing an aluminum alloy plate for a can body according to the present invention, in a scanning electron micrograph of the homogenized Al alloy ingot, the diameter is 0.1 μm to The area ratio of 1 μm particles is configured to be 3.5% or more.

Furthermore, in the present invention, a beverage can body characterized by comprising the above-described aluminum alloy plate for a can body is also the object.

In addition, in one of the preferable embodiments of the beverage can body according to the present invention, a predetermined paint baking process is performed on the above-described aluminum alloy plate for a can body.

Therefore, in such an Al alloy sheet for can bodies configured according to the present invention, the solid solution of Fe, Mn, Si in the hot rolled sheet material of Al alloy having a specific alloy composition that gives it can be provided. By optimizing the amount, as well as fine precipitate particles (α phase) that precipitate during cold rolling of such hot rolled sheet material, high heat resistance softening properties are imparted while ensuring excellent formability, Further, even after heat treatment, it can exhibit excellent can body strength, and can be advantageously used as a can body material.

In addition, according to the method for producing an Al alloy plate for a can body according to the present invention, an Al alloy plate for a can body having excellent characteristics such as compatibility of the formability as described above and the strength of the can body after heat treatment is industrially produced. It can be advantageously manufactured.

It is a graph which shows the variation | change_quantity of the electrical conductivity at the time of performing a compression process at the temperature of 150 degreeC with respect to two Al alloy materials from which an alloy composition differs.

First, an Al alloy that provides an Al alloy plate for a can body according to the present invention has Mn: 0.7 to 1.3% (mass basis, the same applies hereinafter), Mg: 0.8 to 1.5%, Fe: 0.001. 25 to 0.6%, Si: 0.25 to 0.50%, Cu: 0.10 to 0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05 %, And the balance has an alloy composition composed of Al and inevitable impurities, and the reasons for limiting the alloy components are as follows.

[Mn: 0.7 to 1.3%]
Mn (manganese) is a basic alloy element in the Al alloy plate according to the present invention, and contributes to improvement of heat-resistant softening property in a solid solution state in addition to increasing strength. Further, during the manufacturing process, an α-phase compound (Al—Mn—Fe—Si system) is formed with Fe and Si which are inevitably contained impurity elements. The particles of the intermetallic compound have extremely high hardness, and serve to improve the surface properties of the container by preventing seizure between the raw material and the mold during molding. If the Mn content is less than 0.7%, these effects cannot be sufficiently exhibited, and if it exceeds 1.3%, the strength becomes too high. A preferable content of Mn is 0.8 to 1.2%.

[Mg: 0.8-1.5%]
Mg (magnesium) is a component that contributes to an increase in strength of the container by being dissolved in Al. If the Mg content is less than 0.8%, there is a problem that it is difficult to obtain the strength required for the final product, and if it exceeds 1.5%, the strength of the can body becomes too high. This causes a problem that moldability is impaired. A preferable content of Mg is 1.0 to 1.3%.

[Fe: 0.25 to 0.6%]
Fe (iron) forms Al ₆ (Mn, Fe) phase compound and α-phase compound (Al-Mn-Fe-Si system) and Mn-Fe-Si compound together with Mn during casting. And, it is a component that prevents seizure between the material and the mold during molding by the solid lubricating action of these intermetallic compounds. When the Fe content is less than 0.25%, the number of these intermetallic compounds is reduced, causing adhesion to the die during DI molding and causing a problem that the surface properties are lowered. On the other hand, when the Fe content exceeds 0.6%, an Al—Fe—Mn intermetallic compound is excessively formed, which becomes a starting point of cracking, and thus formability. Cause problems. The preferable content of Fe is 0.30 to 0.50%.

[Si: 0.25 to 0.50%]
Si (silicon) forms an α-phase compound (Al-Mn-Fe-Si-based) or Al-Fe-Si-based compound having a solid lubricating action together with Mn and / or Fe described above to form a die during molding. It has the effect of preventing adhesion to the skin. This effect is not sufficient when the Si content is less than 0.25%, and when the Si content exceeds 0.50%, the Al—Mn—Fe—Si intermetallic compound becomes excessive. When it is formed, it becomes a starting point of cracking, and the moldability is impaired. Further, the amount of solid solution Mn is reduced, and the heat softening property is lowered. The preferable content of Si is 0.30 to 0.40%.

[Cu: 0.10 to 0.30%]
Cu (copper) forms an Al—Cu—Mg-based intermetallic compound in the paint baking process and precipitates it, thereby exhibiting an effect of suppressing or preventing a decrease in strength in the paint baking process. This effect is not sufficiently obtained when the Cu content is less than 0.10%, and conversely when it exceeds 0.30%, the work curability at the time of forming increases and the formability decreases. Raise the problem. The preferable content of Cu is 0.15 to 0.25%.

[Zn: 0.25% or less]
Zn (zinc) is a component that improves formability. However, if the content of Zn (zinc) increases, in addition to increasing the cost, a coarse intermetallic compound is formed, causing problems that impair formability. become. Therefore, the Zn content is adjusted to be 0.25% or less. A preferable content of Zn is 0.05 to 0.20%.

[Ti: 0.10% or less and B: 0.05% or less]
Ti (titanium) and B (boron) have a function of refining the cast structure to make the dispersion form and crystal grain structure of the crystallized product generated during casting uniform. However, when the Ti content exceeds 0.10% or the B content exceeds 0.05%, a coarse intermetallic compound is generated, and the formability is lowered. In addition, preferable content of these Ti and B is 0.03% or less and 0.04% or less, respectively.

[Al + inevitable impurities: balance]
The Al alloy which is the material of the Al alloy plate for a can body according to the present invention is composed of Al (aluminum) and unavoidable impurities, that is, elements other than the alloy components described above, in addition to the alloy components described above. It is what is done. In addition, such inevitable impurities are preferably as low as possible so that the plate characteristics are not deteriorated. Generally, the content is not more than the upper limit value of each element of the Al alloy defined in JIS standards and the like. Will be taken. And the total content of each element which becomes such an inevitable impurity is generally 0.15% or less, preferably 0.10% or less.

And, in the Al alloy plate according to the present invention made of an Al alloy having such an alloy composition, the amount of solute Mn after hot rolling (before cold rolling) is 0.25% by mass or more. The amount of dissolved Fe is 0.02% by mass or more, the amount of dissolved Si is 0.07% by mass or more, and the conductivity is 30.0 to 40.0% IACS. It shows heat-resistant softening properties. As the solid solution amount of these elements increases, compound particles composed of Mn, Fe, and Si are finely formed by cold rolling, as will be described later. Further, the solid solution amount of these elements in the hot rolled sheet is limited by the content of each element in the Al alloy, and the maximum conductivity realized by the solid solution amount of these elements is 40.0%. Furthermore, even if the additive element is a solid solution at the maximum, the conductivity is 30.0% IACS or more. In addition, when the solid solution amount of these elements is less than the lower limit defined above, the strength is significantly lowered in the paint baking process.

Further, the Al alloy plate according to the present invention has a property that the tensile strength (TS) in the rolling direction is 280 to 320 MPa as the base plate property. When the tensile strength (TS) is smaller than 280 MPa, there is a problem that the strength of the can body manufactured using such an Al alloy plate is insufficient, and when it exceeds 320 MPa, DI molding is difficult. Problem arises. Furthermore, the Al alloy sheet according to the present invention has a characteristic that the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 270 to 310 MPa. If the tensile strength (ABTS) in the rolling direction after the heat treatment is smaller than 270 MPa, there is a problem that the strength of the can body is insufficient. On the other hand, if it exceeds 310 MPa, the DI molding becomes difficult. In addition, in the Al alloy sheet according to the present invention, the difference between the tensile strength (TS) in the rolling direction and the proof stress (ABYS) in the rolling direction after heat treatment at 205 ° C. × 10 minutes (TS−ABYS) does not exceed 50 MPa. Thus, it is possible to advantageously balance both the formability of the Al alloy plate and the strength of the can after the heat treatment of the can obtained using such an Al alloy plate. It was.

By the way, when manufacturing an Al alloy plate according to the present invention as described above, first, a material that gives the Al alloy composition as described above is melted to obtain an Al alloy molten metal, and then by a known casting technique such as a DC casting method. An Al alloy ingot is formed. Such an Al alloy ingot has an alloy composition comprising the contents of Mn, Mg, Fe, Si, Cu, Zn, Ti and B as defined in the present invention.

Next, the Al alloy ingot is subjected to the same chamfering as before, and then subjected to a specific homogenization treatment in order to obtain the characteristics of the Al alloy plate according to the present invention. That is, in such a homogenization treatment, the homogenized treatment temperature (T: ° C.) of the Al alloy ingot subjected to chamfering is within a range of 550 to 620 ° C. at a heating rate of 30 to 120 ° C./hour. ) And heated for a period of (145−0.24T) time (Hr) or longer at the homogenization temperature (T). In addition, when the rate of temperature increase is slower than 30 ° C./hour, the occupation time of the apparatus becomes longer, the manufacturing cost increases, and when it becomes faster than 120 ° C./hour, a large amount of fine particles are formed, There is a problem that the strength becomes too high and the moldability deteriorates. Further, when the homogenization treatment temperature (T) is lower than 550 ° C., the effect of the homogenization treatment cannot be sufficiently obtained. Raise the problem. This homogenization treatment eliminates segregation of elements present in the Al alloy ingot to form a uniform structure, and precipitates a coarse α-phase compound to exert the function of preventing seizure during molding. It also has features. Then, by setting the holding time of this homogenization treatment to (145-0.24T) or longer, the cross-sectional structure of the treated Al alloy ingot is magnified by a magnification of 100 to 20000 using a scanning electron microscope. In the photograph observed at a magnification, the area ratio of particles having a diameter of 0.1 μm to 1 μm is 3.5% or more, thereby obtaining an anti-seizure effect and Mn necessary for obtaining effective heat softening resistance , Fe, Si can be secured. In addition, as an upper limit of the holding time of the homogenization treatment, from the viewpoint of productivity and the like, generally, 30 hours or less, preferably 20 hours or less is advantageously employed.

After the above homogenization treatment is finished, the Al alloy ingot is directly (immediately) subjected to hot rolling and does not fall below 500 ° C. at a cooling rate of 10 to 90 ° C./hour ( It is also possible to perform hot rolling after cooling to the hot rolling start temperature (500 ° C. or higher). In the case where the Al alloy ingot is cooled, when the cooling rate is lower (slower) than 10 ° C./hour, or when it is cooled to a temperature lower than 500 ° C., the cooling step Mn, Fe, and Si are precipitated in the medium, and the solid solution amount of these elements is lowered. As a result, precipitation of fine particles composed of Mn, Fe, and Si is insufficient during the subsequent cold rolling. Thus, there arises a problem that the heat resistance softening property is lowered. Further, when the cooling rate is larger (faster) than 90 ° C./hour, there is a problem that the temperature distribution in the Al alloy ingot becomes non-uniform and the characteristics of the final product become unstable.

In the present invention, hot rolling for an Al alloy ingot is performed by combining hot rough rolling and hot finish rolling in the same manner as in the past, and the thickness after hot finish rolling is 1.5-4. A plate material of 0 mm will be formed, in which hot rough rolling is performed on the above-described homogenized Al alloy ingot or an Al alloy ingot cooled to a predetermined temperature, The delivery side temperature (material temperature at the end of hot rough rolling) is carried out to be 430 to 550 ° C., so that a plate material with a plate thickness of 20 to 40 mm is formed. Therefore, when the delivery temperature is lower than 430 ° C., there is a problem that the delivery temperature of the hot finish rolling following the hot rough rolling is lowered, and when the delivery temperature exceeds 550 ° C., Coarse recrystallized grains are produced during hot rolling, which may impair the formability. Further, when the thickness of the plate material obtained by this hot rough rolling is less than 20 mm, the workability in the subsequent hot finish rolling is insufficient, and an effective recrystallized structure cannot be obtained after hot finish rolling. On the other hand, when the thickness exceeds 40 mm, the degree of work in hot finish rolling becomes too large, and the problem that the anisotropy at the time of DI molding becomes strong is caused.

Further, in the hot finish rolling subsequent to the hot rough rolling, a known rolling operation is performed such that the delivery temperature (material temperature at the end of hot finish rolling) is 300 to 390 ° C. A plate material having a thickness of 1.5 to 4.0 mm is formed. In this hot finish rolling, it is important to adjust to a recrystallized structure during cooling after coiling of the obtained plate material. If the exit temperature of such hot finish rolling is lower than 300 ° C., the formation of the recrystallized structure becomes insufficient, causing problems that the anisotropy becomes strong and the strength of the product becomes too high. In addition, when this delivery side temperature exceeds 390 degreeC, a recrystallized grain becomes coarse and there exists a possibility of impairing DI moldability. Moreover, when the plate thickness is thinner than 1.5 mm, the degree of work in the subsequent cold rolling process is insufficient, and the strength is lowered. Conversely, when the thickness is excessively greater than 4.0 mm, There is a problem that the degree of processing becomes high and the strength becomes too high. And the amount of the said solid solution Mn, Fe, Si can be ensured by this hot finish rolling.

The hot-rolled sheet obtained as described above is further subjected to cold rolling. In the present invention, the total degree of cold rolling is 75% or more. In addition, cold rolling is performed so that the average rolling speed of the stationary part in the final pass is 700 to 1600 m / min, and an Al alloy sheet having a thickness of 0.2 to 1.0 mm is formed. The cold rolling is carried out according to the same method as in the prior art. At that time, when the total degree of cold rolling is less than 75%, or the average rolling speed of the steady portion is 1600 m / If it is larger than 5 minutes, precipitation of Mn-based compound particles is not sufficient, and heat softening resistance may be reduced. Moreover, when the average rolling speed of the stationary part is smaller than 700 m / min, there is a problem that productivity is remarkably lowered. Furthermore, when the thickness of the Al alloy plate obtained therebelow is less than 0.2 mm, there is a problem that it is difficult to ensure the strength of the can body, while when the plate thickness is greater than 1.0 mm, the weight is increased. It becomes heavier and unsuitable as a beverage can.

Furthermore, in the present invention, the electrical conductivity (S1) of the plate material (hot rolled plate) obtained by the above hot finish rolling and the plate material (cold rolled plate) obtained by the cold rolling described above. The difference (S1-S2) from the conductivity (S2) is 0.2 to 1.6% IACS, in other words, the conductivity of the cold rolled sheet is 28.4% IACS to 39.8%. It is preferable to manufacture the target Al alloy plate so that it is within the range of IACS. When solid solution Mn is sufficiently present, compound particles composed of Mn, Fe, and Si are induced by cold working and finely precipitated, and the heat-resistant softening property can be improved. Incidentally, FIG. 1 shows the results of examining the difference in conductivity before and after the compression test at 150 ° C. simulating cold rolling for two test pieces made of Al alloys having different Mn contents. However, in the test piece made of Al alloy containing Mn, the electrical conductivity is increased by cold working, whereas in the test piece made of Al alloy not added with Mn, cold working is done. The change in the electrical conductivity due to is hardly recognized, and this confirms that the Mn-based compound particles are precipitated by cold working. Basically, in cold rolling, although the conductivity decreases due to processing strain, the conductivity increases due to the precipitation of Mn-based compound particles, so the overall decrease in conductivity is 0. It is within the range of 2 to 1.6% IACS. In addition, when the amount of decrease in the conductivity is smaller than 0.2% IACS, the cold work degree is insufficient, causing a problem of insufficient strength. On the other hand, when it is larger than 1.6% IACS, Mn, Fe, and Si-based precipitated particles induced by cold rolling are insufficient, which causes a problem that the heat softening property is not sufficiently improved.

Then, the Al alloy plate according to the present invention thus obtained is subjected to necessary processing in the same manner as in the prior art to form the desired can body, which is advantageously used as an Al-based beverage can etc. Will be. For example, the Al alloy plate according to the present invention is subjected to degreasing and oiling as necessary, and further includes cup molding, DI molding, trimming, cleaning, drying, painting, baking, necking and flange processing. After that, a beverage can body (can body) is formed, and by attaching a can lid (can end) to this, an intended Al-based beverage can can be produced advantageously.

Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying. In addition to the following examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements can be made.

In addition, in the following examples and comparative examples, for the test material made from the obtained Al alloy plate (base plate: cold rolled plate) or a hot rolled plate that is an intermediate product thereof, according to the following method, Measurement or evaluation.
(1) Tensile strength (TS) in the rolling direction of the base plate
From each Al alloy plate (base plate) obtained in the examples and comparative examples, a JIS No. 5 test material was produced in the rolling direction and a tensile test was carried out in accordance with JIS-Z-2241. The tensile strength (TS) in the direction was measured.
(2) Tensile strength (ABTS) and proof stress (ABYS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes
A test material composed of each Al alloy plate (base plate) is subjected to a heat treatment (205 ° C. × 10 minutes) corresponding to the paint baking process, and then a tensile test is performed in the same manner as in (1) above. Tensile strength (ABTS) and proof stress (ABYS) in the rolling direction of the test material after heat treatment were measured.
(3) Measurement of Si, Fe and Mn solid solution (phenol dissolution method)
After dissolving the matrix component in Al alloy by immersing the small piece sample cut out from the hot-rolled sheet after hot finish rolling obtained in each of Examples and Comparative Examples in phenol at 170 ° C., benzyl Filtration is performed using a filter having a pore size of 0.1 μm while adding alcohol and keeping the solution in a liquid state. Then, the precipitate captured on the filter is dissolved in a hydrochloric acid / hydrofluoric acid mixed solution, and ICP (Inductively Coupled Plasma) emission spectroscopic analysis is performed using a solution obtained by diluting the obtained dissolved solution. Thus, the amounts of precipitated Mn, Fe, and Si were obtained. Moreover, the amount of solid solution Mn, Fe, Si was calculated | required by subtracting the said precipitation amount from content in an ingot.
(4) Conductivity Conductivity meter (SIGMATEST2 manufactured by Forster Co., Ltd.) for the plate material after hot finish rolling (hot rolled plate) and the plate material after cold rolling (base plate: cold rolled plate), respectively. 0.069), the frequency was measured at 960 kHz, and the average value of n = 3 was obtained. In addition, when the plate | board thickness of the test material was less than 1 mm, the test material (plate) was piled up so that the total thickness might be 1 mm or more, and it used for the measurement.
(5) Evaluation of can-making properties For each of the various Al alloy plates (base plates) obtained in Examples and Comparative Examples, cup molding and DI molding were performed at a squeezing rate of 66%, respectively, according to a normal can-making method. Further, after trimming, the same paint baking as before was carried out to confirm the possibility of can making. Further, the seizure situation of the can wall in the can making operation was also visually evaluated.

-Example 1-
First, various Al alloys having the alloy component composition shown in Table 1 below: A1 to A10 were melted in accordance with a conventional method, and then ingots of Al alloys were formed by a semi-continuous casting method. Next, the obtained Al alloy ingot was chamfered in the same manner as before, and then heated and raised to a temperature of 600 ° C. at a rate of temperature increase of 40 ° C./hour using an air furnace. The mixture was warmed and then subjected to a homogenization treatment at 600 ° C. for 10 hours. Note that the value of (145-0.24T) time or more defined in the present invention is 1 hour or more, and the above-mentioned 10-hour homogenization treatment sufficiently satisfies the conditions.

Next, after such homogenization treatment, it is subjected to hot rolling as it is (immediately). First, a reverse rolling mill is used until the sheet thickness reaches 28 mm so that the delivery temperature is in the range of 460 to 510 ° C. Using the same hot rough rolling as in the past, and then performing hot finish rolling for 4 stands until the sheet thickness is 2.2 mm so that the delivery temperature is 300 to 330 ° C. The tandem type rolling mill was used to perform the same method as before. Finally, three passes of cold rolling were performed to produce an Al alloy plate having a thickness of 0.28 mm. The total degree of work in this cold rolling process was 87.3%. At this time, the average rolling speed in the final pass was set in the range of 900 to 1100 m / min. The outlet temperature of the final pass in cold rolling was 145 to 155 ° C.

Test materials (A1 to A10) were prepared for each of the various plate materials made of Al alloys of A1 to A10 obtained in the above steps, and each performance evaluation was performed according to the evaluation method described above. The results are shown in Table 2 below. In Table 2 below, the difference (S1−S2) between the conductivity (S1) of the hot-rolled sheet and the conductivity (S2) of the cold-rolled sheet is shown as the decrease in conductivity in the cold rolling. ing.

As is clear from the results in Tables 1 and 2, all the plate materials made of Al alloys of A1 to A10 have a high tensile strength (TS) in the rolling direction in a state where they have not passed through the coating baking process. However, their can-making ability was good. Further, it was confirmed that the Al alloy plates (test materials) of A1 to A10 had high tensile strength (ABTS) in the rolling direction after heat treatment and were excellent in heat softening resistance.

-Comparative Example 1-
In the various alloy component compositions shown in Table 3 below, plate materials made of various Al alloys of B1 to B13 were manufactured under the same conditions as in Example 1 above. The characteristics of the test materials (B1 to B13) obtained in the production process of the Al alloy sheet were evaluated in the same manner as described above, and the results are shown in Table 4 below.

As is clear from the results of Tables 3 and 4, the B1 test material lacked the amount of Mn added, so the amount of solid Mn was less than the specified range, and precipitation during cold rolling was insufficient. Decreased significantly. As a result, the amount of strength reduction during the baking process was large, and the strength of the can body was insufficient. In addition, in the B2 test material, the amount of Mn added was excessive, and the strength of the base plate was too high, which caused a problem of breaking during can making. Furthermore, the B3 test material was insufficient in strength after baking of the base plate and the paint because the amount of Mg added was insufficient. In the B4 test material, since the amount of Mg added is excessive, the strength of the base plate becomes too high, which causes a problem of breaking during can making. In the B5 test material, since the amount of Fe added was insufficient, the coarse intermetallic compound was insufficient, and surface roughness was induced after canning. Moreover, since the amount of solid solution Fe was insufficient and precipitation during cold rolling was insufficient, the strength was greatly reduced during coating baking.

And, in the B6 test material, since the added amount of Fe is excessive, a coarse intermetallic compound is formed, causing a problem of breaking during can making. In addition, the B7 test material lacked the amount of Si added and lacked precipitation during cold rolling, resulting in a significant decrease in strength during paint baking and insufficient can body strength. In the B8 test material, the amount of Si added was excessive, and a coarse intermetallic compound was excessively formed, causing a problem of breaking during can making. In addition, the amount of Cu added to the B9 test material was insufficient, so that the precipitation strengthening during the coating baking process was insufficient. Therefore, the strength reduction due to coating baking was large, and the can body strength was insufficient. Furthermore, in the test material of B10, since the amount of Cu added is excessive, the strength of the base plate becomes too high, causing a problem of breaking during can making. In addition, in the test materials of B11, B12, and B13, the amount of Zn, Ti, and B added is excessive, so that coarse intermetallic compound particles are formed excessively, and at the time of can making The problem of breaking occurred.

-Example 2-
By employing the alloy component composition (Al alloy: A9) that gives the A9 test material in Example 1, various Al alloy plate materials of C1 to C13 were produced under various production conditions shown in Table 5 below. The basic manufacturing conditions not shown in Table 5 were the same as those in Example 1. Then, using various C1 to C13 Al alloy plate materials obtained in the manufacturing process, test materials (C1 to C13) were prepared, and the same evaluation as in the above examples was performed. The results are shown in Table 6 below.

As is apparent from the results of Tables 5 and 6, each of the C1 to C13 Al alloy plate materials (test materials) has a high tensile strength (TS) in the rolling direction in a state where the coating baking is not performed. However, since it was set to an appropriate value, the can-making properties were all good.

-Comparative Example 2-
By adopting the alloy component composition of Al alloy: A9 in Example 1, various Al alloy plate materials D1 to D9 were produced under various production conditions shown in Table 7 below. The manufacturing conditions not described in Table 7 were the same as those in Example 1. Then, for the test materials (D1 to D9) made of the Al alloy plates (cold rolled plates) of D1 to D9, the plate material characteristics were evaluated, and the results are shown in Table 8 below.

As is clear from the results of Tables 7 and 8, since the D1 test material has a high temperature increase rate during the homogenization treatment, fine Mn, Fe, and Si-based particles are formed during the temperature increase. The strength increased, and the problem of breaking during can making was caused. Further, in the D2 test material, since the holding temperature in the homogenization treatment is low, there is a problem that the homogenization effect is not sufficient, the structure becomes non-uniform, and breaks during canning. In the case of the D3 test material having a too high holding temperature in the processing, a structure in which eutectic melting occurred was caused, the structure became non-uniform, and a problem of breaking during can making was caused. Furthermore, in the D4 test material, since the holding time in the homogenization treatment was shorter than (145-0.24T), the equivalent circle diameter showing the individual lubrication effect was 0.1 to 1.0 μm. The formation of Mn, Fe, Si compound particles was insufficient, and seizure occurred on the surface after canning.

In addition, in the D5 test material, since the cooling rate to the hot rolling (hot rolling) start temperature is small, precipitation proceeds during cooling, and the solid solution amount of Mn, Fe, Si decreases, During the rolling (cold rolling), the precipitation of Mn, Fe, Si-based fine particles becomes insufficient and the heat softening resistance is lowered. On the other hand, the D6 test material has a high cooling rate up to the hot rolling start temperature. In this case, the temperature inside the ingot becomes non-uniform, the material structure varies, and the problem of breaking during can making is caused. In addition, in the D7 test material, since the hot rolling start temperature is low, precipitation proceeds in the process of cooling to the hot rolling start temperature, so that the solid solution amount of Mn, Fe, Si decreases, and Mn, Precipitation of Fe and Si-based fine particles became insufficient, and the heat softening resistance was lowered. As a result, the strength of the can after baking was insufficient.

Furthermore, in the D8 test material, since the total degree of work in cold rolling is insufficient, the problem of insufficient strength is inherent. In addition, in the D9 test material, since the rolling speed of the final pass in the cold rolling process is high, precipitation of Mn, Fe, and Si-based fine particles becomes insufficient during cold rolling, and heat softening resistance is reduced. It was something that caused problems.

Claims

On the basis of mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu : 0.10-0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being aluminum alloy consisting of Al and inevitable impurities A hot-rolled sheet obtained from a cold-rolled sheet, and the hot-rolled sheet has a solute Mn content of 0.25% by mass or more and a solute Fe content of 0.02 The tensile strength (TS) in the rolling direction of the cold-rolled sheet is not less than mass%, the amount of dissolved Si is not less than 0.07 mass%, and the electrical conductivity is 30.0 to 40.0% IACS. Is 280 to 320 MPa, and the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 270 to 310. The aluminum alloy for can bodies, characterized in that the difference between the tensile strength (TS) in the rolling direction and the yield strength (ABYS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 50 MPa or less. Board.
On the basis of mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu : 0.10-0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being aluminum alloy consisting of Al and inevitable impurities A hot-rolled sheet containing 0.25% by mass or more of solid solution Mn, 0.02% by mass or more of solid solution Fe, and 0.07% by mass or more of solid solution Si. And an aluminum alloy hot-rolled sheet for a can body, characterized by having a conductivity of 30.0 to 40.0% IACS.
On the basis of mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu : 0.10-0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being aluminum alloy consisting of Al and inevitable impurities The tensile strength (TS) in the rolling direction is 280 to 320 MPa, the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 270 to 310 MPa, and An aluminum alloy sheet for a can body, wherein the difference between the tensile strength (TS) in the rolling direction and the yield strength (ABYS) in the rolling direction after heat treatment at 205 ° C for 10 minutes is 50 MPa or less.
4. The aluminum alloy plate for can bodies according to claim 3, wherein the electrical conductivity is 28.4% IACS to 39.8% IACS.
On the basis of mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu : 0.10-0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being aluminum alloy consisting of Al and inevitable impurities A step of preparing an aluminum alloy ingot to be
Using such an aluminum alloy ingot, hot rolling is performed, the solid solution Mn amount is 0.25 mass% or more, the solid solution Fe amount is 0.02 mass% or more, and the solid solution Si amount is 0.07 mass%. A step of obtaining a hot-rolled sheet material having the above-mentioned conductivity of 30.0 to 40.0% IACS;
The hot-rolled sheet material is cold-rolled, the tensile strength (TS) in the rolling direction is 280 to 320 MPa, and the tensile strength (ABTS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes is 270 to 310 MPa. And forming a cold rolled sheet having a difference between the tensile strength (TS) in the rolling direction and the yield strength (ABYS) in the rolling direction after heat treatment at 205 ° C. for 10 minutes of 50 MPa or less,
The manufacturing method of the aluminum alloy plate for can bodies characterized by having.
On the basis of mass, Mn: 0.7 to 1.3%, Mg: 0.8 to 1.5%, Fe: 0.25 to 0.6%, Si: 0.25 to 0.50%, Cu : 0.10-0.30%, Zn: 0.25% or less, Ti: 0.10% or less, and B: 0.05% or less, with the balance being aluminum alloy consisting of Al and inevitable impurities After chamfering the Al alloy ingot to be heated, the temperature is raised to a homogenization temperature (T) within a range of 550 to 620 ° C. at a temperature increase rate of 30 to 120 ° C./hour, and the homogenization temperature In (T), a homogenization treatment is performed by holding for (145-0.24T) time or more, and then immediately after completion of the homogenization treatment or at a cooling rate of 10 to 90 ° C./hour. After cooling to the hot rolling start temperature that does not fall below 500 ° C., the exit temperature: 43 Hot rough rolling was carried out to a temperature of ˜550 ° C. to form a plate material with a thickness of 20 to 40 mm, followed by hot finish rolling to a delivery temperature of 300 ° C. to 390 ° C. Sheet thickness: After forming a sheet material of 1.5 to 4.0 mm, cold rolling is performed so that the total processing degree is 75% or more and the average rolling speed of the stationary part in the final pass is 700 to 1600 m / min. A method for producing an aluminum alloy plate for a can body, wherein the plate thickness is 0.2 to 1.0 mm.
The difference (S1-S2) between the conductivity (S1) of the plate material obtained by the hot finish rolling and the conductivity (S2) of the plate material obtained by the cold rolling is 0.2 to 1.6%. The method for producing an aluminum alloy plate for a can body according to claim 6, wherein the method is IACS.
The can according to claim 6 or 7, wherein an area ratio of particles having a diameter of 0.1 µm to 1 µm is 3.5% or more in a scanning electron micrograph of the homogenized Al alloy ingot. Manufacturing method of aluminum alloy sheet for body.
A beverage can body comprising the aluminum alloy plate for a can body according to claim 1, claim 3, or claim 4.
The beverage can body according to claim 9, which has been subjected to a predetermined baking process.