JP4596991B2 - Aluminum alloy clad material for foil container and manufacturing method thereof - Google Patents

Description

  The present invention relates to a clad material for a foil container excellent in corrosion resistance (corrosion resistance) and a method for producing the same.

  Conventionally, aluminum foil containers are widely used not only for portable containers but also for serving foods. As one of the aluminum foil containers, there is a “wrinkled foil container” in which a side wall is wrinkled. The “wrinkled foil container” is excellent in container strength because strength is ensured by wrinkles, and is used as a container for storing a large amount of food (particularly fluid food, thin food, etc.).

  A wrinkled foil container is formed by punching an aluminum foil and drawing it to form a predetermined wrinkled container, and then pressing the material into a die without stretching it as much as possible to generate uniform wrinkles. Wind and mold. The aluminum foil used at this time is an Al alloy containing Mn (for example, No. 3000 series Al alloy) in order to ensure the strength of the wrinkled foil container.

  However, wrinkled foil containers such as liquid foods containing liquid juice or thin-walled foods that are put in wrinkled foil containers, sterilized by heating, frozen, stored for a long time, and then directly heated in an oven to eat. Are often kept in contact with the salt-containing juice for a long period of time. At this time, the liquid juice containing salt corrodes the aluminum of the foil container in a high-temperature and high-humidity state during heating, and corrosion holes are generated. In order to improve the crevice corrosion resistance to this problem, the number 3000 series Al alloy containing Mn is used, with pure aluminum, Al—Zn alloy, Al—Mg alloy, and Al—Zn—Mg alloy as the skin. There has been proposed a composite aluminum foil having a core material (Patent Document 1).

Further, Mg: 0.1 to 2.0% by weight, Cr: 0.03 to 0.5% by weight, optionally containing one or more of Ti, Mn, Cu, Si, Fe, the balance being Al And the foil container with a wrinkle comprised with the composite aluminum foil which coat | covered the skin which consists of an unavoidable impurity is proposed (patent document 2). According to this wrinkled foil container, it is said that the occurrence of crevice corrosion can be suppressed over a long period even for liquid foods containing highly corrosive salt and thin liquid foods.
JP-A-8-308740 JP2002-19835

  However, these prior arts still have room for improvement in terms of corrosion resistance.

  Accordingly, a main object of the present invention is to provide an aluminum alloy clad material for a foil container that is more excellent in corrosion resistance.

  As a result of intensive studies in view of the problems of the prior art, the present inventor has found that the above object can be achieved, and has completed the present invention.

That is, this invention relates to the following aluminum alloy clad material for foil containers, and its manufacturing method.
1. A clad material formed by clad a skin material on both sides of a core material and the core material,
(1) The core material is Fe: 0.2 to 0.4 wt%, Si: 0.05 to 0.25 wt%, Cu: 0.3 wt% or less, Mn: 0.04 to 0.1 Containing aluminum and Mg: 2.2 to 2.8% by weight, the balance being aluminum and inevitable impurities,
(2) The skin material is Fe: 0.2 to 0.4 wt%, Cu: 0.05 wt% or less, Si: 0.02 to 0.15 wt%, and Mg: 0.5 to 1.8 Containing wt%, the balance is made of aluminum and aluminum alloy which is an inevitable impurity,
An aluminum alloy clad material for a foil container.
2. Item 2. The aluminum alloy clad material for a foil container according to Item 1, which is used for a foil container for containing a content having a salt concentration of 0.5% by weight or more.
3. A method for producing the aluminum alloy clad material for a foil container according to Item 1,
(1) Fe, Si, Cu, Mn, and Mg, and Fe, Cu, and Si are included on both sides of the core material made of an aluminum alloy composed of aluminum and inevitable impurities, and Mg is 0% by weight or more 0 A first step of laminating an aluminum alloy containing less than 5% by weight as a skin material;
(2) a second step of diffusing a part of Mg in the core material into the skin material by heat-treating the laminated body;
The manufacturing method of the aluminum alloy clad material for foil containers containing.
4). The material for the skin material is Fe: 0.2 to 0.4% by weight, Cu: 0.05% by weight or less, Si: 0.02 to 0.15% by weight, and Mg is 0% by weight or more and 0% Item 4. The production method according to Item 3, which is less than 5% by weight (particularly 0% by weight or more and 0.4% by weight or less), and the balance is aluminum alloy composed of aluminum and inevitable impurities.
5). Item 5. The method according to Item 3 or 4, wherein the heat treatment temperature is 300 to 450 ° C.
6). The aluminum alloy clad material for foil containers obtained by the manufacturing method according to any one of Items 3 to 5.

  According to the clad material of the present invention, since a combination of a core material and a skin material having a specific alloy composition is employed, corrosion resistance superior to that of the conventional product can be realized. In particular, when the pitting corrosion potential difference between the core material and the skin material is controlled to a constant value, higher corrosion resistance can be obtained.

  For this reason, the clad material of the present invention is suitably used as a container for contents containing, for example, salt (NaCl concentration of 0.5% by weight or more, particularly 2% by weight or more, further 8% by weight or more, further 10% by weight or more). Can do. More specifically, it is effective as a container for food containing salt. The clad material of the present invention can exhibit excellent corrosion resistance for these contents over a long period of time.

1. Aluminum alloy clad material for foil container The aluminum alloy clad material for foil container of the present invention is a clad material formed by clad a skin material on both sides of a core material and the core material,
(1) The core material is Fe: 0.2 to 0.4 wt%, Si: 0.05 to 0.25 wt%, Cu: 0.3 wt% or less, Mn: 0.04 to 0.1 Containing aluminum and Mg: 2.2 to 2.8% by weight, the balance being aluminum and inevitable impurities,
(2) The skin material is Fe: 0.2 to 0.4 wt%, Cu: 0.05 wt% or less, Si: 0.02 to 0.15 wt%, and Mg: 0.5 to 1.8 Containing wt%, the balance is made of aluminum and aluminum alloy which is an inevitable impurity,
It is characterized by that.

Core material : Fe: 0.2-0.4% by weight, Si: 0.05-0.25% by weight, Cu: 0.3% by weight or less, Mn: 0.04-0.1% by weight And Mg: 2.2 to 2.8% by weight, with the balance being aluminum and an aluminum alloy with inevitable impurities.

  The main role of each component of a core material is shown below. However, since the effects of the present invention are obtained by the synergistic action of each component, they are not necessarily limited to the following roles.

  Fe is 0.2 to 0.4% by weight, preferably 0.2 to 0.35% by weight. In particular, the strength of the core material can be increased by adding Fe. Therefore, when the amount of Fe is less than 0.2% by weight, a desired strength cannot be obtained. On the other hand, if the amount of Fe exceeds 0.4% by weight, the corrosion resistance of the core material decreases.

Si is 0.05 to 0.25% by weight, preferably 0.05 to 0.20% by weight. By blending Si, it mainly reacts with Mg to precipitate Mg ₂ Si, thereby increasing the strength of the core material. Therefore, when the amount of Si is less than 0.05% by weight, a desired strength cannot be obtained. Further, there arises a problem that workability in which the amount of Si exceeds 0.25% by weight is lowered and corrosion resistance is also lowered.

  Cu is 0.3% by weight or less, preferably 0.25% by weight or less. By adding Cu, the strength can be particularly increased. Therefore, when the amount of Cu exceeds 0.3% by weight, the corrosion resistance decreases.

  Mn is 0.04 to 0.1% by weight, preferably 0.04 to 0.95% by weight. In particular, the strength of the core material can be increased by blending Mn. Therefore, when the amount of Mn is less than 0.04% by weight, the desired strength cannot be obtained. Moreover, when the amount of Mn exceeds 0.1 weight%, workability (rollability) will fall.

  Mg is 2.2 to 2.8% by weight, and preferably 2.3 to 2.8% by weight. In particular, the strength of the core material can be increased by adding Mg. Therefore, when the amount of Mg is less than 2.2% by weight, the desired strength cannot be obtained. On the other hand, when the amount of Mg exceeds 2.8% by weight, workability (rollability) decreases.

  The thickness of the core material is not particularly limited, and can be set as appropriate depending on the application, usage method, and the like. Generally, it may be about 50 to 100 μm, preferably 60 to 90 μm.

Skin material : Fe: 0.2 to 0.4 wt%, Cu: 0.05 wt% or less, Si: 0.02 to 0.15 wt%, and Mg: 0.5 to 1.8 wt% And the balance is aluminum and an aluminum alloy which is an inevitable impurity. By adopting such an alloy composition, higher strength and corrosion resistance can be obtained. Such an aluminum alloy can be appropriately selected from known pure aluminum alloys.

  The main roles of each component of the skin material are shown below. However, since the effects of the present invention are obtained by the synergistic action of each component, they are not necessarily limited to the following roles.

  Fe is 0.2 to 0.4% by weight, preferably 0.23 to 0.37% by weight. By setting to the above range, excellent corrosion resistance can be obtained while further increasing the strength of the skin material.

  Si is 0.02 to 0.15% by weight, preferably 0.03 to 0.13% by weight. By compounding Si, the strength of the skin material can be increased along with the corrosion resistance.

  Mg is 0.5 to 1.8% by weight, preferably 0.7 to 1.8% by weight. When the amount of Mg is less than 0.5% by weight, it becomes difficult to obtain desired corrosion resistance. On the other hand, when the Mg content exceeds 1.8% by weight, the potential difference from the core material becomes small, the sacrificial effect of the core material is lost, and the desired corrosion resistance cannot be obtained.

  Cu is 0.05% by weight or less, preferably 0.04% by weight or less. In particular, it is desirable to set so that the Cu content of the skin material is smaller than the Cu content of the core material. As a result, the potential of the skin material can be more reliably maintained at a lower level, and higher corrosion resistance can be exhibited.

  The thickness of the skin material (the thickness of each one layer) is not particularly limited, and can be appropriately set according to the application, usage method, and the like. Generally, it may be about 5 to 30 μm, preferably 5 to 25 μm. The thicknesses of both skin materials formed on both surfaces of the core material may be the same thickness or different from each other.

  The ratio of the thickness of the core material to the thickness of the clad material is 100% if the thickness of the core material: the thickness of the skin material (total of two layers) = 70 to 85%: about 15 to 30%. good.

Clad Material The clad material of the present invention can be used as a material for a foil container (particularly the surface in contact with the contents). For example, it can be used as a material for a wrinkled foil container. In particular, it contains contents (food, etc.) containing a relatively high concentration of salt with a salt concentration of 0.5% by weight or more, preferably 2% by weight or more, more preferably 8% by weight or more, and most preferably 10% by weight or more. It can be suitably used as the material of the container to be used.

  Although the thickness (total thickness) of the clad material is not limited, it is generally set appropriately within the range of 0.1 to 0.4 mm according to the type of the intended container, the type of contents, and the like. it can.

  In the case of forming a container using the clad material of the present invention, a known method such as blanking, drawing, wiping down, curling or the like may be followed.

2. Manufacturing Method of Aluminum Alloy Cladding Material for Foil Container The cladding material of the present invention can basically be manufactured according to a known manufacturing method as long as the above-described configuration is obtained. For example, a core material and a skin material alloy are prepared through a process such as casting, chamfering, and homogenizing a raw material adjusted to a predetermined composition, and then a skin material alloy is formed on both sides of the core material alloy. A predetermined clad material can be obtained by laminating and carrying out processes such as rolling and annealing.

  In particular, it can be suitably produced by the production method of the present invention. That is, (1) Fe, Cu, Si is contained on both sides of a core material made of an aluminum alloy consisting of Fe, Si, Cu, Mn, and Mg and the balance being aluminum and inevitable impurities, and Mg is 0% by weight. A first step of laminating an aluminum alloy containing less than 0.5% by weight as a skin material; (2) heat treating the laminate to partially remove Mg in the core material; It can obtain by the manufacturing method of the aluminum alloy clad material for foil containers including the 2nd process made to diffuse in.

  In the first step, Fe, Cu, Si is contained on both sides of the core material made of an aluminum alloy consisting of Fe, Si, Cu, Mn, and Mg and the balance being aluminum and inevitable impurities, and Mg is 0 weight. An aluminum alloy containing at least 0.5% and less than 0.5% by weight is laminated (clad) as a skin material.

  The core material is made of Fe, Si, Cu, Mn, Mg, and an aluminum alloy with the balance being aluminum and inevitable impurities. As for the alloy composition, the core material as the clad material finally obtained is the above-mentioned 1. What is necessary is just to adjust suitably so that it may become the composition ratio shown by (5). That is, the obtained core material is Fe: 0.2 to 0.4 wt%, Si: 0.05 to 0.25 wt%, Cu: 0.3 wt% or less, Mn: 0.04 to 0.1 What is necessary is just to set so that it may become aluminum alloy containing a weight% and Mg: 2.2-2.8weight%, and remainder with aluminum and an inevitable impurity. For example, as shown in the examples described later, Fe: 0.2 to 0.4 wt%, Si: 0.05 to 0.25 wt%, Cu: 0.3 wt% or less, Mn: 0.04 -0.1 wt% and Mg: 2.3 to 2.8 wt% (especially 2.3 to 2.7 wt%), with the balance being aluminum and an inevitable impurity aluminum alloy as the core material Can be used.

  As the skin material, an aluminum alloy containing Fe, Cu, and Si and containing Mg in an amount of 0 wt% or more and less than 0.5 wt% is used. In this way, by using a material for skin material having a composition with low Mg content, excellent workability can be obtained in the cladding material manufacturing process, and a cladding material in which cladding defects are suppressed or prevented is manufactured. As a result, a clad material having excellent corrosion resistance and the like can be provided.

  The composition of the skin material is not limited except for the Mg content. In the present invention, Fe: 0.2-0.4% by weight, Cu: 0.05% by weight or less, Si: 0.02-0.15% by weight, and Mg is 0% by weight or more and 0.5% by weight. It is desirable to use an aluminum alloy containing less than wt% (especially 0 wt% or more and 0.4 wt% or less) with the balance being aluminum and inevitable impurities.

  In the first step, the skin material is laminated on both surfaces of the core material. The lamination method is not particularly limited, and may be carried out according to a known clad material manufacturing method. In this case, it is desirable that the core material and the skin material are previously formed into a plate shape so as to be easily laminated.

  Next, in the second step, a part of Mg in the core material is diffused into the skin material by heat-treating the laminate.

  The laminate may be the one immediately after passing through the first step, or may be one that has passed through another step (such as a rolling step) after the first step. In other words, the second step can be performed as intermediate annealing and / or final annealing. In particular, in the final annealing, it is desirable to carry out the second step as final annealing in that the thickness of the clad material is already thin and energy efficiency is improved.

  The heat treatment temperature is not limited, but it is generally desirable that the heat treatment temperature is 300 to 450 ° C, particularly 330 to 430 ° C. When the temperature is less than 300 ° C., the heat treatment takes too much time, which may be economically disadvantageous. Moreover, when it exceeds 450 degreeC, there exists a possibility that material may discolor.

  The heat treatment time is usually in the range of 5 to 50 hours although it depends on the heat treatment temperature and the like. By setting to such a range, a more excellent Mg diffusion effect can be obtained efficiently.

  In the production method of the present invention, in addition to the first step and the second step, general steps (for example, hot rolling, cold rolling, etc.) applied in the aluminum clad material production method are appropriately performed as necessary. You can also.

  The features of the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to the examples.

Example 1
After melting and casting the raw materials having the compositions shown in Table 1, the core material alloy (thickness 400 mm) and the skin material alloy (thickness 50 mm) were produced by chamfering and homogenization.

  Subsequently, the alloy for skin materials was arranged on both surfaces of the alloy for core materials in the combination of the core material and the skin material shown in Table 2, respectively. These were hot-clad (500 ° C.) clad rolled (1 pass) to a thickness of 4 mm, and then subjected to intermediate annealing (about 380 ° C. × 5 hours) and cold rolling (3 passes) to a thickness of 0.090 mm. Clad foil materials (invention sample No. 1-7, comparative sample No. 8-13) of 10% thickness each for the skin material and 80% core material were prepared.

  Blanking, drawing, wiping down, and curling forming steps were performed on the clad foil material with a composite die to produce a foil container.

  An aqueous solution containing soy sauce (soy sauce concentration 20% by weight (salt concentration 2%)) was placed in the obtained container and stored at 40 ° C. for 14 days, and then the corrosion state of the container was observed. In the observation of the corrosion state, the case where the through hole was not opened in the foil was evaluated as “◯”, and the case where the through hole was opened was evaluated as “x”. The results are shown in Table 2.

  Moreover, the Mg content contained in the skin of the produced aluminum alloy clad material (near the center in the thickness direction of the skin) was measured. The results are shown in Table 2. As a measuring method, the clad material after the final annealing was mechanically removed from the skin surface to the vicinity of the center in the thickness direction of the skin material with emery polishing paper, and then measured and determined by emission spectroscopic analysis.

  Further, the clad property of the clad foil (existence of occurrence of clad defects) was examined. The results are shown in Table 2. Evaluation of the cladability was carried out according to the procedure of the clad rolled material. The evaluation is “◎” when there is no clad defect at all, “◯” when there is no problem in practical use, “△” when some of the clad defects are recognized, and those where the clad defects are noticeable. It was set as “x”.

  As is apparent from the results in Table 2, it can be seen that the aluminum alloy clad material for foil containers of the present invention exhibits excellent corrosion resistance and the like.

Claims (6)

A clad material formed by clad a skin material on both sides of a core material and the core material,
(1) The core material is Fe: 0.2 to 0.4 wt%, Si: 0.05 to 0.25 wt%, Cu: 0.3 wt% or less, Mn: 0.04 to 0.1 Containing aluminum and Mg: 2.2 to 2.8% by weight, the balance being aluminum and inevitable impurities,
(2) The skin material is Fe: 0.2 to 0.4 wt%, Cu: 0.05 wt% or less, Si: 0.02 to 0.15 wt%, and Mg: 0.5 to 1.8 Containing wt%, the balance is made of aluminum and aluminum alloy which is an inevitable impurity,
An aluminum alloy clad material for a foil container. The aluminum alloy clad material for a foil container according to claim 1, which is used for a foil container for containing contents having a salt concentration of 0.5% by weight or more. A method for producing an aluminum alloy clad material for a foil container according to claim 1,
(1) Fe, Si, Cu, Mn, and Mg, and Fe, Cu, and Si are included on both sides of the core material made of an aluminum alloy composed of aluminum and inevitable impurities, and Mg is 0% by weight or more 0 A first step of laminating an aluminum alloy containing less than 5% by weight as a skin material;
(2) a second step of diffusing a part of Mg in the core material into the skin material by heat-treating the laminated body;
The manufacturing method of the aluminum alloy clad material for foil containers containing. The skin material is Fe: 0.2 to 0.4% by weight, Cu: 0.05% by weight or less, Si: 0.02 to 0.15% by weight, and Mg is 0% by weight to 0% by weight. The manufacturing method of Claim 3 which is less than 0.5 weight% and is an aluminum alloy which remainder consists of aluminum and an unavoidable impurity. The manufacturing method of Claim 3 or 4 whose heat processing temperature is 300-450 degreeC. The aluminum alloy clad material for foil containers obtained by the manufacturing method in any one of Claims 3-5.