JPS62146251A - Manufacture of medium strength aluminum alloy plate for decoration - Google Patents

Abstract

PURPOSE:To obtain an Al alloy plate having superior mechanical properties, formability and luster by subjecting an Al alloy contg. prescribed percentages of Mg, Cu, Si and Fe to homogenization, rolling and finish annealing under prescribed conditions. CONSTITUTION:An Al alloy contg., by weight, 1.5-3% Mg, 0.01-0.1% Cu, <=0.005% Si and <=0.005% Fe is refined. The Al alloy is homogenized at 450-600 deg.C, hot rolled to 3-8mm thickness and finish-annealed at 150-400 deg.C. Cold rolling may be carried out before the finish annealing.

Description

[Detailed description of the invention] [Industrial use RF] The present invention is a medium strength aluminum alloy plate for decoration.
：Notice ± 7k tji lj! 1 Doo 1 [Background of the Invention] Currently, when an aluminum alloy plate is intended for decoration, its surface is chemically polished or electrolytically polished to give the surface shine. Then, anodization treatment is further performed for the purpose of protecting the surface.

Conventionally, aluminum alloy plates used for this kind of decoration were
Commercially available or industrial purity aluminum ingots are used.

However, although conventional aluminum alloy plates made using such base metals are once given brightness by brightening treatment using chemical polishing or electrolytic polishing, the surface becomes cloudy due to subsequent anodizing treatment, and the required performance is not achieved. A problem arises in that it is difficult to obtain. .

The inventor investigated the cause and found the following: that is, an intermetallic compound consisting of Al and impurities such as Fe and Si that inevitably enter the aluminum base metal (
Mainly 3 Al-Fe A I-F
p-Stfu) is
It forms and precipitates during 7b and subsequent hot rolling. If there are many precipitates of these intermetallic compounds, when anodic oxidation treatment is performed after imparting brightness to the surface by chemical polishing or electrolytic polishing, these will be mixed into the anodic oxide film and reduce the transmittance of the film. It is.

In order to prevent this, it has been found that reducing the content of Fe and St, which are inevitably included in the material, as much as possible is highly effective.

The present invention has been made based on this knowledge.

[Summary of the invention] The present invention provides Mg: 1.5 to 3.0%, Cu: 0.01 to
o, i%, Si: 0-005% or less, Fe: 0.005
% or less, other unavoidably contained impurity elements are each 0.005% or less, and the total is 0.01% or less,
Aluminum alloy material consisting of balance Al is heated to 450°C to 60°C.
After homogenizing at 0°C, hot rolling to a thickness of 3 to 8 mm, then directly or after cold rolling, 150
It is characterized by final annealing at a temperature of ℃ to 400℃.

The reasons for limiting the ingredients will be explained below.

Fe: An element that is unavoidably contained in aluminum metal and forms an Al-Fe-based intermetallic compound. At around 200°C, only 0.01% of this solid solution exists, so it becomes a precipitate and is dispersed in large quantities in the alloy, which mixes into the anodic oxide film and makes the surface cloudy. Therefore, Fe is 0.
0.005% or less is essential.

Si: When used alone, Si does not easily impair the brightness, but it also reduces the transparency of the anodic oxide film. It also combines with Mg to form an intermetallic compound called Mg, Si,
Decreases film transparency. Therefore, St is 0.005%
The following are required.

Cu: Has the effect of improving brightness during chemical polishing.

If it is less than 0.01%, it has no effect, and if it exceeds 0.1%, the transparency of the film decreases and the color tone of the film changes, so Cu is in the range of 0.01% to 0.1%.

Mg: An essential element to provide strength to the product of the present invention. If it is less than 1.5%, sufficient strength and strength cannot be obtained, and if it exceeds 3%, the strength is too high and the moldability is impaired. The range is 1.5 to 3%.

Other elements are also less than 0.005% each, total 0.01
% or less, the brightness will be impaired.

The homogenization heat treatment temperature is in the range of 450°C to 600°C, because if it is less than 450°C, intermetallic compounds will precipitate, and if it exceeds 600°C, blistering or burning will occur due to gas in the ingot.

If the hot-rolled sheet thickness is less than 3 mm, the amount of subsequent cold rolling to the product will be small, and the uniformity of the structure will not be obtained, impairing the workability of the product. If the thickness exceeds 8 mm, the subsequent cold working rate will increase and it is not economical, so the hot rolled plate thickness should be 3 to 8 m.
It is m.

The heat treatment in the final step is to obtain moldability, and if the strength is lower than 150°C, the recrystallized grains will become coarse and roughness of the molding vinegar surface (orange peel) will occur, so the temperature should be in the range of 150°C to 400°C. .

Note that cold rolling is necessary when the product plate thickness is 3 mm or less, and when it exceeds 3 mm, it is not necessarily necessary when considering bright alumite properties. I don't mind the condition.

[Example] Alloys shown in Table 1 having strengths comparable to those of the products of the present invention were manufactured using the manufacturing process shown in Table 2, and various properties were investigated.

Alloy 1 corresponds to conventional alloy A3052, and alloy 2 corresponds to A32
52, and Alloy 3 is the alloy of the present invention.

Samples A, C, and C were produced under the same manufacturing conditions, and C, II, and E were alloys of the present invention, but they were used to investigate the effect of the thickness of the product and the presence or absence of cold rolling.

It is something.

Table 3 shows the characteristics of these products.

The products of the present invention (C), (2), (E) and (F) do not retain color in both mechanical properties and molding process compared to conventional alloys (A) and (B). On the other hand, the alumite properties after brightening treatment were all significantly improved compared to conventional products, and the effects of the products of the present invention are clear.

Next, the results of measuring the reflectance of Samples A, C, and C by changing the thickness of the anodic oxide film after electrolytic polishing are shown in the drawing.

Although almost the same value of reflectance is obtained during electrolysis, it decreases as the thickness of the anodic oxide film increases. Compared to the conventional alloy, where the decrease is significant, the decrease with the present alloy is small.

[Effect of the invention] The method for producing a medium-strength aluminum alloy plate with excellent bright alumite properties according to the present invention has the above-mentioned structure, has excellent mechanical properties and formability, and has excellent It is possible to produce a shiny aluminum alloy plate, which is extremely effective for decorative purposes.

[Brief explanation of drawings]

The drawing is a graph showing the relationship between anodized coating and reflectance.

Claims (1)

[Claims] Mg: 1.5-3.0%, Cu: 0.01-0.1%,
Si: 0.005% or less, Fe: 0.005% or less, and other unavoidably contained impurity elements are each 0.00%.
After homogenizing an aluminum alloy material consisting of 5% or less, and the balance being 0.01% or less at 450°C to 600°C, it is hot rolled to a plate thickness of 3 to 8mm, and then, as it is, Or after cold rolling, 150℃~400℃
A method for producing a decorative medium-strength aluminum alloy plate, which comprises final annealing at a temperature of °C. However, % is weight %.