JPS58221266A - Shaped article of aluminum - Google Patents

Abstract

PURPOSE:To obtain a shaped article of Al having improved strength in spite of its complex shape, by forming an Al sheet and by partially heat treating it by selective heating and rapid cooling. CONSTITUTION:An Al sheet is formed into a dumping cover, and the parts shown by the oblique lines are selectively heated to 350-550 deg.C and rapidly cooled at once by spraying cold water, dipping in cold water, or blowing cold air. In case of a soft Al alloy contg. Mn, the same effect is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the strength of molded articles made from sheets of aluminum.

Molded aluminum sheets are widely used as lids for retort containers and composite containers (containers made from composite materials). Naturally, it is necessary to use a material that is easy to process, and the deeper the molding depth or the more complex the shape, the more easily it is required to stretch. Aluminum alloys are usually used for this purpose, with the addition of manganese to make them softer and less stiff.

On the other hand, it is desirable for aluminum molded products to have high strength depending on the use. For example, when it comes to lids for composite containers, wrinkle-free deep-drawn lids are generally used, but because they require precision machining, the material is the manganese-based aluminum alloy mentioned above. I have to use it.

However, containers using this lid have the disadvantage that the lid deforms considerably when subjected to a drop test.

An object of the present invention is to provide a molded product made from an aluminum sheet, which has a deep molding depth and/or a complex shape, and has improved strength.

This object is achieved in accordance with the present invention by an aluminum molded product in which a sheet of aluminum is molded and the resulting molded product is heat-treated to selectively heat and rapidly cool a portion of the molded product to increase its strength. Surprisingly, when the heat treatment is applied to the entire molded article, the strength is improved more markedly when the heat treatment is applied to only a portion of the molded article.

Heating is performed such that the temperature of the selected portion of the aluminum molded article is 350° C. or higher. At temperatures that do not reach the lower limit of 350°C, no effect can be expected from the variation of the aluminum m weave, while on the other hand, heating at high temperatures exceeding, for example, 550°C will cause the aluminum to melt, although it depends on the composition of the aluminum alloy. This is inappropriate in that it also causes a temperature rise in the instantaneous contact area, which is negative for the heating of the selected area.

To perform heating, for example, prepare a heating plate corresponding to the shape of the selected part, heat it to a temperature slightly higher than the above heating temperature using electric heating or any other means, and bring it into contact. good. The heating duration is
Although it varies somewhat depending on the temperature and thickness of the sheet, a few seconds to several tens of seconds is sufficient. Cooling can be done by spraying cold water immediately after leaving the heating plate, immersing it in water, or contacting it with a low-temperature metal plate. Any method can be used, such as blowing cold air, etc. In short, it is sufficient if the heated portion is rapidly cooled.

In order to heat the selected portion more effectively, it is advisable to cool the unheated portion at the same time.

The parts to be selectively heated are determined by the shape of the aluminum molded product. It is recommended to select a pattern that produces the so-called "beam effect."

To give some examples in the drawings, in a drop lid having the cross-sectional shape shown in FIG. 1, only the shaded portion in FIG. 2, 3, or 4 is heated. Further, in the case of a drop lid with a drinking spout whose cross section is shown in FIG. 5, only the shaded portion in FIG. 6, for example, is heated.

Of course, various other heating patterns are also effective. Further, the present invention is applicable not only to the composite container lid described above but also to both types of molded containers with and without wrinkles and their lids.

EXAMPLE A composite container drop lid having the shape shown in FIG. 1 was molded from a 130 μm thick manganese-based soft aluminum alloy foil laminated with 100 μm thick polyethylene. It has a diameter of 55 mm and a depth of 15 mm, with four folds around the outside.

Using a hot plate heated to 400° C., the patterned portions shown in FIGS. 2 to 4 were heated for 10 seconds, and immediately cooled by applying a cold metal plate. For comparison, we prepared one whose entire surface was heated with a hot plate at a temperature of 9,400°C and another which was not heat-treated at all.

As the container body, PE, 20μ/paper 300g/rr? /
A cup-shaped container was used using a laminate of PE20μ/A113μ/PE80μ.

The container was filled with water heated to 95° C., covered with the above-mentioned lid, and the flange portion was heat-sealed.

After cooling, the containers were subjected to a drop test to compare the strength of the lids. The results are shown below: Deformation of the lid Contents leakage/invention product Small None Full heating Small None to slightly untreated product Medium None

[Brief explanation of drawings]

FIG. 1 is a sectional view of a composite container drop lid, which is an example of the aluminum molded product of the present invention. FIGS. 2, 3, and 4 are all plan views showing examples of selective heating portions in the drop lid of FIG. 1. FIG. 5 is a sectional view similar to FIG. 1 of a drop lid which is another example of the aluminum molded product of the present invention. FIG. 6 is a plan view similar to FIGS. 2 to 4, showing an example of the selectively heated portion of the drop lid of FIG. 5; Patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Sou Suga Genius 1
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Claims (4)

[Claims] (1) An aluminum molded product characterized in that the strength of the aluminum sheet is increased by applying heat treatment to the resulting molded product by selectively heating and rapidly cooling a portion of the molded product. (2) The aluminum molded article according to claim 1, which is heated at a temperature of 350° C. or higher. (3) The aluminum molded article according to claim 1, wherein the aluminum is a soft aluminum alloy containing manganese. (4) The aluminum molded product according to claim 1, wherein the molded product is a lid of a composite container.