JPS58224144A - Aluminum alloy developing color spontaneously - Google Patents

Abstract

PURPOSE:To obtain an Al alloy having high mechanical strength in spite of its high extrusibility and assuming an arbitrary color tone from light gray to black by adding restricted amounts of Cu and Mg to an Al-Si alloy. CONSTITUTION:This alloy consists of 1.7-4.4% Si, 0.12-0.30% Cu, 0.16-0.30% Mg and the balance Al. A billet of the alloy is homogenized at <=about 560 deg.C, preheated at about 350-500 deg.C, extruded, and aged. Anodic oxidation is then carried out by a conventional method to form a colored film assuming a desired color from light gray to black in accordance with the homogenizing temp. The alloy is not inferior to a 6063 alloy T5 material in mechanical strength, and it has a favorable surface state and superior extrusibility.

Description

DETAILED DESCRIPTION OF THE INVENTION Iron 17-44%, copper 012-030%, magnesium 0.16-Q. By containing 30qb as an essential component and remaining aluminum containing other unavoidable impurities, it has excellent mechanical strength despite good extrudability, and can also be produced in any color tone ranging from light gray to grayish black. The purpose of the present invention is to provide a naturally coloring aluminum alloy that can be used to color objects.

It has been known for a long time that the anodic oxide film of a wrought material of A° C.-81 alloy exhibits a gray color, and it has been used for building materials and the like. However, for example, 4043 alloy, which is a typical naturally colored aluminum alloy, has weak strength and corresponds to a semi-hard wrought aluminum material of 99% purity, and must be made thick to be used in building window frames and the like. Also, this 404
The alloy that is hardened by the precipitation of Mg2Si in order to improve the 3 alloy has a strength equivalent to that of 6063-T5 material, but has poor extrudability, cannot obtain a black plate-making color, and is hardened by the precipitation of Mg2Si. There is a drawback that the oxide film has a yellowish tinge.

Furthermore, there are also disadvantages such as slight differences in the anodizing treatment conditions are sensitively reflected in the color tone of the film, and color unevenness is likely to occur.

The present invention eliminates the above-mentioned drawbacks, that is, it is capable of producing a desired color tone over a wide range from light gray to dark gray-black with good reproducibility, and is machined to the same level as, for example, 6063 alloy T alloy. They developed a naturally colored aluminum alloy that has excellent mechanical strength and extrudability.

The naturally colored aluminum alloy according to the present invention will be explained below.

In general, Si in AjA-Si naturally colored alloys does not undergo any change during anodizing treatment, but instead migrates into the film as it is, imparting color to the film depending on its particle shape and distribution density. In the present invention, in addition to containing 1.7 to 4.4% of Si as a color-forming element, Cu is added to Q, +2 to 0.3%.
0, Mg is included in -Q,16''-0,30.

A billet made of such an alloy composition is homogenized at a temperature of 560°C or lower, then preheated and extruded at a temperature of 350 to 500°C, subjected to an aging treatment ('r5 treatment), and then subjected to a conventional anodic oxidation treatment. When this is carried out, a desired colored film can be obtained over a wide range of colors from light gray to grayish black depending on the temperature of the homogenization treatment. The material with this alloy composition has mechanical strength comparable to that of 6063 alloy Irs material, and has a good surface condition.
It has excellent extrudability.

That is, when the SI content is less than 1.74, the desired gray color cannot be obtained unless an extremely thick anodic oxide film is formed, and stable color development is difficult.
If it exceeds 4%, roughness will occur and extrudability will be significantly reduced, and a large amount of smut will be generated during pre-treatment for surface treatment, which will be difficult to remove and will not contribute to the deepening of the color tone. The Si content is preferably 17 to 44, and the O is 012
%, the strength improvement is unsatisfactory, and 03
If the ratio exceeds 0, the film formation efficiency will decrease and the desired color tone will not be obtained.
By setting the Mg content to 30%, it not only improves the strength but also has excellent extrudability, and furthermore, the desired color tone can be obtained.Moreover, if the Mg content is less than 16%, it will not harden even after aging treatment. There is no point, and if it exceeds 0.30%, not only will productivity decrease, but the colored film will become yellowish, making it impossible to obtain a beautiful gray-black color, and reducing the Mg content to 0. It has been found that by setting the content to 0.16 to 0.30%, mechanical strength and extrudability can be balanced and excellent, and a desired color tone can be obtained.

And when homogenizing, the temperature exceeds 560℃.
If it is carried out at one temperature, there is a risk that the billet with the above composition will melt, so if the homogenization treatment is carried out at a temperature below 560℃, it will be It is possible to produce an anodic oxide film that has a light gray tone, or a gray-black tone at low temperatures.

Father, by setting the extrusion temperature to 350-500C,
It has good extrudability, is less likely to cause brown unevenness, and has a good surface condition, such as no microcracks at the edges of the material.

Specific examples will be described below.

Example 1 Afi-4 Si-0,2%Cu-0,25%p
Jg and other yearly billets consisting of avoidable impurities,
Homogenization treatment at 560℃ for 12 hours, then 350-500℃
Preheating temperature in °C (the homogenization temperature 540 °C, 490 °C
'C, 490°C for 470°C, 440°C, 390°C, respectively, 490C1470C1450C14501:
) was used to extrude the solid material and follower material. and,
After aging at 180° C. for 6 hours, a film of about 20 μm was formed by conventional sulfuric acid anodic oxidation.

This product has a good surface condition, a mechanical strength comparable to that of 6063 Alloy T alloy, and a desired color range from pale gray to plate-making black depending on the homogenization temperature. It was made in different colors. In addition, in the drawing,
The characteristics shown by the solid line are those of this example, and the numbers indicate the temperature during the homogenization process.

Example 2 Afl-2%5i-0,2%Cu-0,25%Mg
A film was chemically formed in the same manner as in Example 1 using a billet containing other inevitable impurities.

Similar to the one in Example 1, this material had a good surface condition, and its mechanical strength was as good as that of 6063 alloy'l5 material, and it became thinner depending on the homogenization temperature. Desired results were obtained over a wide range of colors ranging from gray to dark gray-black. In the drawings, the characteristics indicated by dotted lines are those of this example, and the numbers indicate the temperature during the homogenization process.

Comparative Example I A billet consisting of Afl, -5.5% 5i-0.15% Mg and other impurities was prepared in the same manner as in the previous example.

The characteristics of this composition are shown by dashed lines in the drawings. or,
The numbers indicate the temperature during the homogenization process.

Comparative example 2 J-5,51i-n, ts%Mg-0,15%O
A billet containing u and other inevitable impurities was prepared in the same manner as in the previous example.

The characteristics of this composition are shown by the two-dot chain line in the drawing. or,
The numbers indicate the temperature during the homogenization process.

Comparative Example 3 A billet consisting of kQ-4,0,'lsi-0,251Mg and other impurities was prepared in the same manner as in the previous example.

The characteristics of this composition are shown by the three-dot chain line in the drawing. or,
The numbers indicate the temperature during the homogenization process.

As can be seen from these results, with the alloy composition according to this example, a wide range of arbitrary coloring densities can be obtained by controlling the homogenization treatment conditions. -'' to 'l''; L L
(F5rゞ(D f!v ;1Fl(7) @ 0””
As mentioned above, the naturally colored aluminum alloy according to the present invention has Si 1.7 to 4.44, Cu O, 12 ~0.3
0%, Mg 0.16 to 0.30% as essential components, and other unavoidable impurities as well as residual hR. Regardless of the film thickness, the desired color tone can be freely controlled over a wide range from light gray to deep gray-black, and it also has high mechanical strength, with mechanical properties comparable to, for example, 6063 alloy 15 material. It also has features such as excellent extrudability.

[Brief explanation of the drawing]

The drawing is made of naturally colored aluminum alloy that is saw and eye resistant. It is a graph showing the characteristics of values. ″T1゛Electric

Claims (1)

[Claims] 3i 1.7-4.4'%, Ou o12-0.30
%, Mg 0.16-0.30% as an essential component, and contains other inevitable impurities and the remainder M.