JPH07268531A - Aluminum alloy plate for thinned redraw cans with a total draw ratio of 2.3 or more - Google Patents

Abstract

(57) [Summary] [Object] To provide an aluminum alloy sheet for a thin-walled redraw can having a total drawing ratio of 2.3 or more, which is excellent in strength and formability. [Constitution] Mg: 0.3-2.0 wt%, Si: 0.7-
Contains 1.5 wt% Ti: 0.01-0.1 wt
%, B: 0.001 to 0.05 wt%, Be: 0.000
1 to 0.0005 wt%, Cr: 0.4 wt% or less, one or two or more, an aluminum alloy plate consisting of the balance Al and unavoidable impurities, the alloy plate before forming the can body An aluminum alloy plate for a thinned redrawing can having a total drawing of 2.3 or more, which is obtained by laminating a plastic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy sheet for a thin-walled redraw can having a total drawing ratio of 2.3 or more, which is excellent in strength and formability.

[0002]

2. Description of the Related Art Conventionally, a can body made of an aluminum alloy plate for forming has a relatively good formability even if it is cold-rolled at a high rolling rate to enhance its strength.
A 3004 (Al-1.2 wt% Mn-1.0 wt% Mg) alloy hard plate has been used.

Generally, as a method of processing a side-seamless can (side seamless can) having a high hermeticity, a metal material such as a tin plate, a tin-free steel plate or an aluminum plate is squeezed with a die and a punch. A typical example is DI processing in which a cup is formed by subjecting the cup to at least one step of drawing, and then ironing is applied between an ironing punch and a die to thin the container body. The can obtained by this processing method has a thick container bottom and high strength, but the wall thickness is about 1/3 thinner than the bottom, so the wall strength is low, and the inside of the container is Since the part easily buckles, it is mainly used for containers such as beer and carbonated drinks to which some internal pressure is applied.

On the other hand, as a processing method of food cans or beverage cans requiring a certain amount of strength on the side wall of a can such as a negative pressure can, there is a drawing-redrawing process. Among them, after the deep drawing, the DRD processing method of thinning the metal material by bending and extending the working curved portion of the redrawing die is disclosed in JP-A-56-501.
No. 442. According to this DRD processing, the radius of curvature of the curved portion of the redrawing die can be reduced, whereby the alloy plate can be bent and extended to reduce the wall thickness of the can side wall.

The thinning process in this case has an effect of correcting the thickening of the side wall plate thickness of the re-drawing can opening, and this processing method makes the base plate thickness thinner than the DI processing method, but the wall thickness becomes thicker. Since a can with high strength is generally obtained, it can be used in a method of forming a can without internal pressure. Further, ironing processing is not required, and it is possible to simplify the can manufacturing process and reduce pollution factors due to removal of oil generated during the can manufacturing process. In addition, Japanese Patent Publication No. 59-34580 discloses a method of laminating a thermoplastic resin before forming the metal plate.

[0006]

In recent years, it has been strongly desired to develop a material having excellent moldability and higher strength in order to expect an economic effect. Among the materials suitable for processing side seamless cans, tin plate and tin-free steel plate are high-strength materials, but they have the drawback of being inferior in recyclability. Therefore, the development of aluminum materials has been particularly desired from the viewpoint of resource saving. However, the conventionally used JIS3004 alloy has insufficient strength as an aluminum alloy for negative pressure thinning redraw cans.

[0007]

As a result of various studies in view of this, the present invention has developed an aluminum alloy plate for a thin-walled redraw can having a total drawing ratio of 2.3 or more, which is excellent in strength and formability. .

That is, according to the present invention, Mg: 0.3 to 2.0 wt.
%, Si: 0.7 to 1.5 wt%, and Ti:
0.01-0.1 wt%, B: 0.001-0.05 wt
%, Be: 0.0001 to 0.0005 wt%, Cr:
An aluminum alloy plate containing one or more of 0.4 wt% or less and the balance Al and unavoidable impurities, wherein a thermoplastic resin is laminated on the aluminum alloy plate before forming the can body. 1. A total aperture ratio characterized by 2.
It is an aluminum alloy plate for a thinned redrawing can of 3 or more.

[0009]

The reason for limiting the composition of the alloy sheet of the present invention will be described below. In the following, wt% is simply abbreviated as%. Mg is an element that gives strength in cooperation with Si, and has a Mg content of 0.
The reason for limiting the content to 3 to 2.0% is that if it is less than 0.3%, the strength is low, and if it exceeds 2.0%, the formability deteriorates. Si is an element that provides strength in cooperation with Mg, and the reason for limiting the Si content to 0.7 to 1.5% is
This is because if it is less than 0.7%, the strength to withstand thinning at the time of can forming cannot be obtained, and if it exceeds 1.5%, the formability deteriorates.

One or more of Ti, B, Be and Cr are added because Ti and B are effective in refining the crystal grains of the ingot, and Be is the molten metal during melt casting. It is effective in preventing the oxidation of, and it is particularly preferable to add it as the Mg content becomes higher. Cr has the effect of improving strength.

Therefore, the Ti content is 0.01 to 0.1%.
The reason for limiting the above is that if it is less than 0.01%, the above-mentioned effects cannot be sufficiently obtained, and if it exceeds 0.1%, coarse Al ₃ Ti is crystallized and the formability is deteriorated. B content 0.0
The reason why the content is limited to 01 to 0.05% is that if it is less than 0.001%, the above-mentioned effect is not sufficiently obtained, and if it exceeds 0.05%, TiB ₂ particles are formed and the formability is deteriorated. .
The reason why the Be content is limited to 0.0001 to 0.0005% is that if the content is less than 0.0001%, the above-mentioned effect cannot be sufficiently obtained, and if it exceeds 0.0005%, its toxicity becomes a problem. . The reason why the Cr content is 0.4% or less is that
This is because if it exceeds 0.4%, a coarse crystallized product is formed and the moldability is deteriorated.

The purpose of laminating a thermoplastic resin on an aluminum alloy plate for a thinned redraw can having a predetermined plate thickness will be described. When the DI processing method is currently used, a known anticorrosive protective coating is applied to the inner surface and the outer surface of the can body. It is generally difficult to apply this protective coating to the alloy plate to be processed prior to DI processing, and therefore, it is necessary to apply the coating evenly to the inner or outer surface of the can after forming the alloy plate into a can. , The efficiency is significantly reduced.

In general, since thermoplastic resins have excellent workability, they can be preliminarily applied to the alloy sheet before forming the can body, and compared with the case where the formed can body is coated, The coating process can be streamlined and simplified. Further, the alloy sheet of the present invention has increased strength when baking is applied to a molded can body or when a thermoplastic resin is thermally bonded to the alloy plate, and strength that can withstand thinning of the side wall portion of the can body is obtained.

[0014]

EXAMPLES The present invention will be described below with reference to examples. Table 1
The alloy having the composition shown in (1) is cast by a normal melting method, the ingot is face-polished, and homogenized at 540 ° C. for 12 hours.
Hot rolling and cold rolling (after intermediate annealing if necessary, cold rolling) were performed to obtain a plate material having a thickness of 0.2 mm. This plate material was heated in a continuous annealing furnace at 550 ° C. for 10 seconds to produce an alloy plate, and a polyethylene terephthalate film having a thickness of 20 μm was thermally adhered to both surfaces of the alloy plate.

With respect to this, the tensile strength, yield strength and elongation of the base plate were measured, and at the same time, the yield strength and the formability after baking treatment were examined. The results are shown in Table 2. The conditions for baking coating are 20
It was set to 5 ° C. for 10 minutes. The formability of the alloy plate after baking coating was 160 mm with a blank diameter using an actual press molding machine.
mm, the aperture ratio of 1.4, the primary redraw ratio of 1.3, and the secondary redraw ratio of 1.2, and then the third redraw ratio was changed and examined. DR of a can body with an inner diameter of 66 mm and an internal capacity of 250 ml or more from a 0.2 mm thick aluminum alloy plate after baking coating
Since the total draw ratio is 2.3 or more in order to perform the D processing and reduce the thickness of the can side wall to 20% of the thickness of the blank, it is necessary that the total draw ratio is 2.3 or more. 3 or more is indicated by O, and less than 2.3 is indicated by X. The uniformity of the side wall of the can after molding was evaluated by the presence or absence of a constriction.

[0016]

[Table 1]

[0017]

[Table 2]

As is clear from Table 2, the examples according to the present invention showed the formability of the total drawing ratio of 2.3 or more, which is the object of the present invention, and no constriction was observed on the side wall of the can. On the other hand, in Comparative Example, the strength after baking, the moldability, and the constriction on the side wall of the can were poor.

[0019]

As described above, according to the present invention, an aluminum alloy sheet for a thin-walled redraw can having a total drawing ratio of 2.3 or more, which is excellent in strength and formability, can be obtained. Play.

Claims (1)

[Claims] 1. Mg: 0.3 to 2.0 wt%, Si: 0.
7 to 1.5 wt% and further Ti: 0.01 to 0.1
wt%, B: 0.001 to 0.05 wt%, Be: 0.00
01-0.0005 wt%, Cr: 0.4 wt% or less, and an aluminum alloy plate containing one or more of Cr and 0.4 wt% or less, and the balance Al and unavoidable impurities. An aluminum alloy plate for a thinned redrawing can having a total drawing ratio of 2.3 or more, which is obtained by laminating a thermoplastic resin.