JPH06116674A - Aluminum alloy sheet for thinned redrawn can excellent in strength and formability - Google Patents

Abstract

PURPOSE:To provide an aluminum allay sheet for a thinned redrawn can excellent in strength and formability and used for the can barrel body of a can of food or the like. CONSTITUTION:The aluminum allay sheet for a redrawn can excellent in strength and formability is a one contg., by weight, 5.5 to 10.0% Mg and furthermore contg., as necessary, 0.00005 to 0.0005% Be and one or two kinds of 0.01 to 0.1% Ti and 0.001 to 0.05% B, and the balance Al with inevitable impurities.

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, which is excellent in strength and formability and is mainly used for can bodies such as food cans which require strength.

[0002]

2. Description of the Related Art Generally, tin plates, tin-free steel plates, metal plates such as aluminum plates are used as a processing method for side-seamless cans (side seamless cans) with high sealing performance such as food cans and beverage cans. DI (Drawing and Ironing) processing for forming a cup by drawing at least one step between the drawing die and punch and then ironing between the ironing punch and die to thin the container body The law is typical. With this processing method, the bottom of the container is thick and has high strength, but the thickness of the side wall is thinned to about 1/3 of that of the bottom, the strength of the side wall of the can is low, and the side wall of the can is Since it easily buckles, it is mainly used for containers such as beer and carbonated drinks to which a certain amount of internal pressure is applied. On the other hand, there is a drawing-redrawing method as a processing method of a side-seamless food can or non-carbonated beverage can that requires a certain amount of strength on the side wall of the can because a negative pressure is applied. Among them, after deep drawing, "bending and stretching" in the working curved part of the redrawing die
A DRD (drawing / redrawing) processing method for working to reduce the thickness of a metal material is also described in JP-A-56-501442. In this case, by reducing the radius of curvature of the curved portion of the redrawing die, the alloy plate can be bent and stretched to reduce the thickness of the can side wall. The thinning process has the effect of correcting the thickening of the side wall plate thickness of the re-opening can opening. This processing method generally provides a can with a thin base plate thickness but a thick wall thickness and high strength as compared with the DI processing method. Therefore, it can be used for a method of forming a can without applying internal pressure. In addition, this processing method does not require ironing, which makes it possible to simplify the can manufacturing process and reduce pollution factors generated during the can manufacturing process.
Further, Japanese Patent Publication No. 59-34580 describes a method of laminating a thermoplastic resin before forming the metal plate in order to improve formability. And, conventionally, as an aluminum alloy plate for forming used for the body of cans such as food cans and beverage cans, it shows relatively good formability even when subjected to cold rolling with a high rolling rate to increase strength. , JIS
3004 alloy hard plate has been used.

[0003]

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 poor recyclability. From the viewpoint of resource saving,
The development of aluminum materials has been desired. However, the JIS 3004 alloy that has been conventionally used has insufficient strength as an aluminum alloy for a thinned redraw can which is subjected to negative pressure.

[0004]

As a result of intensive studies in view of the above situation, the present invention has a sufficient strength for a thin-walled redraw can and has a total drawing ratio of 2.3 or more. An aluminum alloy plate for thin-walled redraw cans having excellent properties was developed. The first invention is characterized by containing 5.5 to 10.0 wt% of Mg and the balance being Al and inevitable impurities. It is an aluminum alloy plate for a thinned redraw can excellent in strength and formability, and the second invention is Mg 5.5 to 10.0.
An aluminum alloy plate for a thin-walled redraw can excellent in strength and formability, characterized by containing wt% and Be0.00005 to 0.0005 wt% and the balance consisting of Al and unavoidable impurities. 3 invention is Mg 5.5 to 10.0 wt
%, Ti0.01-0.1 wt%, B0.0
Containing one or two of 01-0.05 wt%,
An aluminum alloy plate for a thinned redraw can, characterized in that the balance comprises Al and unavoidable impurities. The fourth invention is Mg 5.5 to 10.0 wt%, Be 0.00005 to.
0.0005 wt%, and Ti of 0.01 to 0.
An aluminum alloy plate for a thinned redrawing can, characterized by containing one or two of 1 wt% and 0.001 to 0.05 wt% B, and the balance being Al and unavoidable impurities. In the first to fourth inventions, it is desirable to laminate a thermosetting resin before molding, because the moldability will be further improved.

[0005]

Next, the reason why the alloy composition is limited as described above in the first to fourth inventions will be described. Mg is an indispensable additional element for increasing strength. When the amount of Mg increases, the strength of the side wall of the thin can increases in the redrawing process, and the work hardening index (n value) increases and uniform deformability increases, so the redrawability is excellent and uniform for thinning. Keep sex. To form a can body with an inner diameter of 66 mm and an internal capacity of 250 ml or more from an aluminum alloy plate having a thickness of 0.15 to 0.2 mm by DRD (drawing / redrawing), a total drawing ratio of 2.3 or more and
It is necessary to reduce the thickness of the can side wall by 20 to 25% compared to the thickness of the base plate. The total drawing ratio is the product of the drawing ratios of each deep drawing process. The Mg content is 5.5 to 10.0 wt% (hereinafter simply referred to as%
The reason is that the redrawing can be performed with less than 5.5%, but constriction occurs during the thinning process, and the uniformity of the side wall plate thickness in the can height direction is impaired. 1
This is because if it exceeds 0.0%, the rolling property is deteriorated and the manufacturing becomes difficult. Be has the effect of preventing the oxidation of the molten metal during melt casting, and is particularly effective as the Mg content increases. Be
The content is limited to 0.00005 to 0.0005% because if it is less than 0.00005%, the sufficient effect cannot be obtained.
This is because if it exceeds 05%, its toxicity becomes a problem. T
Addition of one or two of i and B is Ti and B
Is because it is effective for refining the crystal grains of the ingot. The Ti content is limited to 0.01 to 0.1%, if it is less than 0.01%, a sufficient effect cannot be obtained, and if it exceeds 0.1%, coarse A
This is because l ₃ Ti crystallizes and the formability deteriorates. Further, the B content is limited to 0.001 to 0.05% because
This is because if it is less than 001%, a sufficient effect cannot be obtained, and if it exceeds 0.05%, AlB ₂ particles are generated and the formability deteriorates. The aluminum alloy sheet of the present invention can be produced by the usual steps of melt casting, homogenization treatment, hot rolling and cold rolling.

Next, the effect of laminating the thermoplastic resin on the aluminum alloy sheet for redraw cans before forming will be described. At present, when the DI processing method is used, the inner surface and the outer surface of the can body are coated with a publicly known anticorrosive protective paint. It is generally difficult to apply this protective coating to the alloy plate to be processed prior to DI processing, and it is necessary to apply the coating evenly to the inner or outer surface of this can after forming the alloy plate into a can, which is extremely efficient. Is bad. Since the thermoplastic resin has excellent workability, it is possible to apply it to the alloy plate before forming the can body, and it is possible to apply the coating process compared to the case where the formed can body is painted. It is possible to streamline and simplify.

[0007]

EXAMPLES The present invention and examples will be described in more detail below. [Example 1] Various alloys having the compositions shown in Table 1 were cast by an ordinary melting method, homogenized after surface grinding was performed at 520 ° C for 24 hours, and hot rolled and cold rolled to a thickness of 0. It was a plate material of 0.2 mm. This plate material was heated in a continuous annealing furnace at 530 ° C. for 10 seconds to produce an alloy plate. Formability of this alloy sheet was determined by using an actual press forming machine under the conditions of a blank diameter of 160 mm, a drawing ratio of 1.4, a primary redrawing ratio of 1.3, and a secondary redrawing ratio of 1.2. The next redraw ratio was changed, and the total draw ratio was calculated from the limit draw ratio of the third redraw and evaluated.
The thinning rate was constant at 20%. The moldability is indicated by ◯ when the total drawing ratio is 2.3 or more and by X when it is less than 2.3. The uniformity of the side wall was evaluated based on the presence or absence of a can side wall.

[0008]

[Table 1]

As is clear from Table 1, the present invention No. 1
Nos. 10 to 10 are all conventional examples. 15 was superior in strength and formability, the total drawing ratio was 2.3 or more, and the constriction of the side wall portion did not occur even by DRD processing. On the other hand, Comparative Example No. 1 whose Mg content is less than the range of the present invention. In Comparative Example No. 11, the strength was insufficient and the side wall portion was constricted, and the Mg content was larger than the range of the present invention. No. 12 cannot be rolled to a predetermined plate thickness, and has a Ti content and a B content each exceeding the range of the present invention.
No. It can be seen that the moldability of Nos. 13 and 14 is poor.

[Example 2] Example N of the present invention in Example 1
o. A polyethylene terephthalate film having a thickness of 20 μm was thermocompression-bonded to both surfaces of the alloy sheets 1, 4, 6, and 8 before forming, and the sheets were drawn in the same manner as in Example 1 to evaluate the formability. The total aperture ratio is 2.3 or more,
Good moldability was exhibited.

[0011]

As described above, according to the present invention, an aluminum alloy sheet for a redrawing can, which is excellent in strength and formability, can be obtained, and has a remarkable industrial effect.

Claims (5)

[Claims] 1. An aluminum alloy plate for a thin-walled redraw can excellent in strength and formability, characterized by containing 5.5 to 10.0 wt% of Mg, and the balance being Al and unavoidable impurities. 2. Mg 5.5-10.0 wt%, Be0.0
An aluminum alloy plate for a thin-walled redraw can, which is excellent in strength and formability, characterized by containing 0005 to 0.0005 wt% and the balance being Al and inevitable impurities. 3. The alloy contains 5.5 to 10.0 wt% of Mg, 0.01 to 0.1 wt% of Ti, and 0.001 to 0.05 of B.
An aluminum alloy plate for a thinned redrawing can, characterized in that it contains one or two of wt% and the balance is Al and unavoidable impurities. 4. Mg 5.5-10.0 wt%, Be0.0
005 to 0.0005 wt%, and Ti0.
Aluminum alloy for thinned redrawing cans, containing one or two of 01 to 0.1 wt% and 0.001 to 0.05 wt% B, and the balance consisting of Al and unavoidable impurities Board. 5. The aluminum alloy plate for a thinned redraw can according to claim 1, wherein a thermosetting resin is laminated before forming.