JPH06100970A - Aluminum alloy for extrusion excellent in bright alumite @(3754/24)registered trademark) characteristic - Google Patents

Abstract

PURPOSE:To provide an aluminum alloy for extrusion excellent in brightness characteristic after chemical polishing treatment and even after anodic oxidation. CONSTITUTION:An aluminum alloy having a composition, wherein the contents of Si and Mg are regulated to 0.3-0.6% and 0.45-0.90%, respectively, in order to maintain extrudability and strength and also the contents of Cu and Fe are regulated, respectively, to 0.05-0.20% and <=0.1% in order to improve brightness characteristics, is cast and then subjected to homogenizing treatment at 560-610 deg.C for 4-24hr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy to be used for producing an aluminum extruded profile by extrusion molding, and particularly to an invention relating to an aluminum alloy for extruding a decorative part requiring glitter.

[0002]

2. Description of the Related Art Conventionally, there has been widely known a method for producing an aluminum alloy for producing a product having excellent luster by subjecting it to chemical polishing treatment or electrolytic polishing treatment, followed by anodizing treatment called so-called alumite treatment. Has been.

For example, Japanese Patent Laid-Open Publication No. 57-51249.
JP-A-62-270757 and the like.

However, although these aluminum alloys are excellent as aluminum alloy plates produced by rolling, they have very poor extrudability when they are subjected to extrusion molding, causing clogging in the extrusion die, There is a problem in that the surface of the extruded profile becomes uneven and the external appearance is significantly reduced.

On the other hand, the JIS A6063S alloy, which is widely known as an extrusion alloy, is liable to cause clouding or uneven gloss on the surface of the product when chemically or electrolytically polished and anodized.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an aluminum alloy having excellent glitter while maintaining extrudability.

[0007]

[Means for Solving the Problems] JIS A6063S alloy usually contains Si; 0.20 to 0.60% by weight, Mg;
It is contained in an amount of 0.45 to 0.90% by weight (hereinafter,% means% by weight). It is preferable that the amount of Si is small in order to improve the glitter, but precipitation of Mg ₂ Si is required to maintain the material strength.

Therefore, 0.30 to 0.60% of Si is added to 0.45 to 0.90% of Mg. Ideally, the ratio of Mg: Si = 1: 0.6 is good. Furthermore, JIS
Although Cu is not usually added to the A6063S alloy, research has revealed that the addition of Cu to the aluminum alloy during the chemical polishing or electrolytic polishing is more excellent in brilliance.

However, if Cu is added in an amount of 0.20% or more, the corrosion resistance deteriorates, so the range of 0.05 to 0.20% is desirable. Further, Fe does not particularly affect chemical polishing or electrolytic polishing, but clouding occurs in the chemical conversion film during anodizing treatment. Therefore, it is desirable to set it to 0.1% or less. The above components are added to an aluminum ingot having a purity of 99.9% or more to produce an aluminum alloy.
Therefore, inevitable impurities may be contained in an amount of 0.1% or less.

As described above, the molten metal whose components have been adjusted is cast into a so-called billet, but the components are segregated as they are and sufficient glitter cannot be obtained. As a result of various examinations of the subsequent homogenizing treatment conditions, 560 to 60 It has been clarified that the treatment at 610 ° C. for 2 to 24 hours is good.

In JIS A6063S alloy, usually 520
Homogenization treatment is carried out at ˜560 ° C., and surface defects are generated at the time of extrusion at 560 ° C. or higher.

[0012]

【Example】

Example 1 An example of the brightening treatment using the aluminum alloy according to the present invention will be shown below. A billet having a diameter of 204 mm and a length of 500 mm is preheated to 440 ° C., a plate-shaped material having a thickness of 3 mm and a width of 30 mm is extruded by a 3000 ton direct extruder at an extrusion speed of 15 to 20 m / min, and then 195 ° C. × 120
Perform prescription treatment.

Next, phosphoric acid 70-85%, nitric acid 3-3.
A 5% chemical polishing liquid was treated at 95 to 100 ° C. for 60 seconds, pickled with 20% nitric acid, and then washed with an electrolytic solution containing 20% nitric acid.
0 to 120 A / m ² , 30 minutes, anodized, about 1
A 0 μm alumite film was formed. Table 1 shows the evaluation results of the glitter. As a comparative example, JIS A606
The same treatment with 3S alloy is also shown.

For the measurement, a specular color difference meter SCD-1 manufactured by Murakami Color Research Laboratory was used, and a specular color standard plate (X = 75.1) was used.
0, Y = 81.66, Z = 96.66, L = 90.4)
The brightness difference ΔL value with Here, the minus sign indicates that the brightness is lower than that of the standard plate.

[0015]

[Table 1]

Example 2 Using an aluminum alloy according to the present invention, an extruded profile having a substantially T-shaped cross section shown in FIG. 1 is extruded at a speed of 15 to 20 m.
The same chemical polishing and anodic oxidation treatment as in Example 1 was performed at a speed of 1 / min.

As a comparative example, a JIS A6063S alloy was similarly extruded at a extrusion speed of 15 to 20 m / min and subjected to surface treatment. Then, the aluminum alloy according to the present invention has no uneven gloss on the surface.
The A6063S alloy was clouded as a whole, and gloss unevenness was generated at the intersection a between the horizontal rib 1 and the vertical rib 2.

[0018]

EFFECTS OF THE INVENTION By using the aluminum alloy according to the present invention, it is possible to produce a product having excellent glitter without impairing the extrudability. Furthermore, good uniform gloss can be obtained even in extruded profile materials that require cross-sectional shapes of ribs such as exterior molding parts for automobiles, and conventional exterior molding parts that require glitter are made of stainless steel or plated. Although we had to rely only on the processed products, extruded profiles made of aluminum alloy made it possible and improved the design.

[Brief description of drawings]

FIG. 1 is a cross-sectional shape of an automobile exterior molding.

[Explanation of symbols]

 1 ... Lateral rib 2 ... Vertical rib a ... Intersection

Claims (1)

[Claims] 1. A weight ratio of Mg; 0.45 to 0.90%,
Si; 0.30 to 0.60%, Cu; 0.05 to 0.2
5%, Fe; 0.1% or less, unavoidable impurities; 0.05%
Below, an aluminum alloy consisting of the balance Al was cast and
An aluminum alloy for extrusion, characterized by being soaked at 60 to 610 ° C for 2 to 24 hours.