JPH08311589A - Aluminum alloy material for reddish beige-colored anodic oxidation coating and its production - Google Patents

Abstract

PURPOSE: To provide an Al alloy material capable of forming a sufficiently reddish uniform beige-colored anodized film with superior reproducibility by specifying a composition consisting of Mn, Fe, Cu, Si, and Al and also specifying the area occupancy, at the sheet surface, of a ferrous intermetallic compound and its electric conductivity, respectively. CONSTITUTION: In an Al alloy material having a composition consisting, at least, of, by weight, 1.0-1.6% Mn, 0.3-1.0% Fe, 0.01-0.1% Cu, <=0.2% Si, and the balance Al, the area occupancy of a ferrous intermetallic compound of >=0.5μm major axis at the sheet surface is regulated to 0.1-0.3% and also its electric conductivity Ea is regulated so that it is lower than the electric conductivity Eb after annealing treatment at 450 deg.C for 4hr, and Eb-Ea>=5%IACS is satisfied. This Al alloy can be obtained by subjecting an Al alloy with the composition to homogeneous heat treatment at >=550 deg.C for >=3hr, to hot rolling at <=320 deg.C finishing temp., and further to cold rolling without process annealing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for an aluminum alloy material for use after being subjected to an alumite treatment, for example, a building material such as a building curtain wall or an interior material, or a vehicle, an article, a container, an ornamental article, etc. Aluminum alloy material,
And a method for manufacturing the same.

[0002]

2. Description of the Related Art Aluminum alloy plate (article) products used for building materials or vehicles, articles, containers, decorations, etc. are often anodized for the purpose of imparting decorativeness and improving corrosion resistance. It is known that a colored alumite film having various tones peculiar to the alloy is formed on the surface thereof. Conventionally, Mn of A3003 alloy etc. is 1.0 to
It is known that, when an aluminum alloy plate containing about 1.5 wt% is subjected to an alumite treatment in a sulfuric acid bath, a beige alumite film with a slight reddish color is sometimes formed on the surface, but it is usually industrially used. Beige colored alumite film with a uniform reddish color due to browning or black spots even when the A3003 alloy plate produced by a general available production method is anodized in a sulfuric acid bath. Couldn't get

As means for solving such a problem, Japanese Patent Publication No. 42-14290 and Japanese Patent Publication No. 43-19.
As seen in Japanese Patent No. 737, an alloy obtained by adding V, W, etc. to an Al-Mn alloy, and as seen in Japanese Patent Laid-Open No. 11-11897, rapid heating during intermediate annealing and final annealing,
Al-Mn alloys or Al-Mn-Mg alloys that have been rapidly cooled have been proposed.

[0004]

However, the above-mentioned V
Addition of W and W has a problem in scrap recovery, and in a simple Al-Mn alloy or Al-Mn-Mg alloy, even if the above rapid heating and rapid cooling are performed, redness is scarce, Moreover, it was revealed by the study of the present inventors that it is very difficult to obtain a color developability with good reproducibility.

[0005]

As a result of various studies in view of the above points, the present invention provides an aluminum alloy material capable of reproducibly obtaining a beige colored alumite film having a uniform and sufficiently reddish color, and a method for producing the same. It was developed.
That is, the invention of claim 1 of the present application has at least Mn1.0
.About.1.6 wt%, Fe 0.3 to 1.0 wt%, Cu0.
An area occupancy rate on the plate surface of an Fe-based intermetallic compound containing 01 to 0.1 wt%, Si 0.2 wt% or less, and the balance aluminum and having a major axis of 0.5 μm or more. Is 0.1 to 0.3%, and the electric conductivity Ea of the material is 4 at 450 ° C.
It is an aluminum alloy material for beige colored alumite with a reddishness, which is smaller than the electric conductivity Eb when subjected to time annealing treatment and has a difference in electric conductivity (Eb-Ea) of 5% IACS or more.

Further, according to the second aspect of the present invention, after homogenizing heat treatment at a temperature of 550 ° C. or higher for 3 hours or more, hot rolling at an end temperature of 320 ° C. or lower is performed without intermediate annealing. The method for producing an aluminum alloy material for reddish beige colored alumite according to claim 1, wherein cold rolling is performed. In the invention of claim 3 of the present application, after the cold rolling is performed, the hot rolling is performed at an end temperature of 320 ° C. or less, and the cold rolling is performed without intermediate annealing.
Final annealing in which the temperature is raised to 400 to 600 ° C. at a temperature rising rate of 00 ° C./min or more, the temperature is maintained for 1 minute or less, and then cooled to 200 ° C. or less at a cooling rate of 100 ° C./min or more, or The method for producing an aluminum alloy material for reddish beige colored alumite according to claim 1, wherein the final annealing is performed by heating at a temperature of less than 280 ° C for less than 10 hours. The final annealing is performed to impart desired strength to the rolled material rolled to the final plate thickness, improve workability, and the like. In the present invention, casting, which is a pre-process of the homogenizing heat treatment, may be performed by a known semi-continuous casting method or the like, and is not particularly limited.

Further, according to the invention of claim 4 of the present application, after carrying out a homogenizing heat treatment at a temperature of 550 ° C. or higher for 3 hours or more, hot rolling is carried out, and then cold rolling is carried out when cold rolling is carried out. 2. The method for producing an aluminum alloy material for reddish beige colored alumite according to claim 1, characterized in that annealing at a temperature of 550 [deg.] C. or higher for 10 minutes or more is performed at least once during or after the above. .

The aluminum alloy material produced by the method according to any one of claims 2 to 4 is subjected to a degreasing / etching treatment with an alkali or acid solution to obtain a sulfuric acid concentration of 10 to 30.
In a vol% electrolytic bath, electrolytic treatment was performed with a direct current at a bath temperature of 10 to 30 ° C. and a current density of 0.5 to 3 A / dm ² , and a film thickness of 1
By forming an alumite film having a thickness of 0 to 30 μm, a uniform and reddish beige colored aluminum alloy material can be obtained.

[0009]

The invention according to claim 1 of the present application provides a reddish color by defining the alloy composition of the Al-Mn-based alloy and the metal structure of the material (amount of intermetallic compound, solid solution amount of Mn) within a predetermined range. It is intended to obtain a certain beige colored alumite film. First, the role of the additional element and the reason for limiting the content thereof in the present invention will be described. Mn dissolves in Al and is incorporated into the alumite coating, and has the effect of developing the coating into a reddish beige color. In the present invention, the Mn content is limited to the range of 1.0 to 1.6 wt%, but the reason is that if it is less than 1.0 wt%, beige color development cannot be obtained. Further, when the content exceeds 1.6 wt%, Mn that cannot be completely dissolved precipitates as Mn-based precipitates, and the film becomes brown or has black spots, and a material having a beautiful alumite film peculiar to the present invention. Because you can't get.

The addition of Fe makes it possible to obtain a beige color which is further reddish due to the action of the Fe-based intermetallic compound. In the present invention, the content of Fe is 0.3 to
It is limited to within the range of 1.0 wt% because the reason is 0.
If it is less than 3 wt%, F taken in the alumite film
This is because there are few e-based intermetallic compounds and it is not possible to obtain a beige color with a sufficient redness. On the other hand, if it exceeds 1.0 wt%, the amount of the Fe-based intermetallic compound having a major axis of 0.5 μm or more becomes too large, and as a result, the film becomes yellow or black spots are formed, and This is because a material having a beautiful alumite film peculiar to the invention cannot be obtained.

When Cu is added, it is possible to obtain a beige color which is further reddish. In the present invention, the Cu content is limited to the range of 0.01 to 0.1 wt%, but the reason is that if it is less than 0.01 wt%, a sufficient effect cannot be obtained. Also, if it exceeds 0.1 wt%, defects may occur in the alumite coating and the corrosion resistance may decrease.

In the present invention, the Si content is 0.2 w
Although it is limited to t% or less, the reason is that if it exceeds 0.2 wt%, Mn tends to precipitate as Mn-based precipitates,
This is because a sufficient solid solution amount of Mn cannot be secured and a reddish beige color cannot be obtained. Impurities other than Si do not have an adverse effect on the color developability of the film as long as the amount of impurities is usually unavoidably included, and therefore, it is not necessary to specifically control. Further, if Ti added for refining the ingot structure is 0.03 wt% or less, the coloring property of the present invention is not hindered.

Next, in the invention of claim 1 of the present application, the reason why the metallographic structure of the material is defined within a predetermined range will be described. The Fe-based intermetallic compound has the effect of exhibiting a reddish beige color. Thus, the area occupation rate of the Fe-based intermetallic compound having a major axis of 0.5 μm or more on the plate surface is limited to the range of 0.1 to 0.3% when the ratio is less than 0.1%. If the effect is insufficient and exceeds 0.3%,
This is because the film becomes yellow or black spots occur, and a material having a beautiful alumite film peculiar to the present invention cannot be obtained.

In the present invention, the conductivity is defined by
This is for defining the amount of Mn solid solution effective for reddish beige color development. That is, in the present invention, the electric conductivity Ea of the material is
When the material is annealed at 450 ° C. for 4 hours (ie,
The difference in conductivity (Eb-Ea) was defined to be 5% IACS or more with respect to the conductivity Eb in the state where Mn was sufficiently precipitated). The reason is that (Eb-Ea) was 5% IAC.
If it is less than S, the solid solution amount of Mn is not sufficient and reddish beige color cannot be obtained.

Next, the reasons for limiting the manufacturing conditions in the second aspect of the present invention will be described. First, the homogenizing heat treatment of the ingot at a temperature of 550 ° C. or higher for 3 hours or more is
Mn-based precipitates that were deposited during casting were dissolved as much as possible,
This is to secure the amount of Mn solid solution in the alloy and to stabilize the Fe-based intermetallic compound. That is, the heating temperature is 5
When the temperature is 50 ° C. or lower, or the heating time is less than 3 hours, the amount of Mn solid solution required for reddish beige color development cannot be secured, no matter how the manufacturing conditions after hot rolling are devised.
This is because a film having a beautiful alumite film peculiar to the present invention cannot be obtained due to browning of the film or black spots. It is desirable that the heating temperature is as high as possible,
600-620, which does not cause partial dissolution by heating
C is most desirable. Further, it is desirable to lengthen the heating time as long as possible, but considering cost and the like, 6 to 12 hours is most desirable.

The ingot subjected to the homogenizing heat treatment is hot-rolled to about 2 to 10 mm by a conventional method. In the present invention, the end temperature of hot-rolling is 320 ° C. or less. To do. This is because the time during which the rolled plate is in the high temperature state is shortened as much as possible to suppress the precipitation of Mn. After the above hot rolling, cold rolling is performed to the final plate thickness without intermediate annealing, but the reason why intermediate annealing is not performed is to avoid precipitation of Mn due to annealing. In the invention of claim 3 of the present application, after the cold rolling, when the final annealing is performed to impart desired strength to the rolled material or to improve workability, a) a temperature rise of 100 ° C./min or more 400 ~ at speed
Heating to 600 ° C. and holding at that temperature for less than 1 minute, then cooling to below 200 ° C. at a cooling rate of 100 ° C./min or more, or b) heating at a temperature below 280 ° C. for less than 10 hours, etc. Annealing under the conditions is for suppressing precipitation of Mn during annealing.

Next, the reason for limiting the manufacturing conditions in the invention of claim 4 of the present application will be described. First, the reason for limiting the homogenizing heat treatment condition of the ingot is the same as that of the invention of claim 2.
Next, during or after the cold rolling, annealing at a temperature of 550 ° C. or higher for 10 minutes or more is performed at least once so that the Mn precipitated during hot rolling is sufficiently re-dissolved. This is to obtain a reddish beige color.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Aluminum alloys having the compositions shown in Table 1 (invention alloys Nos. A to F, comparative alloys No. G to J) were melted and cast into ingots having a thickness of 500 mm and a width of 1000 mm, and after homogenizing heat treatment, After hot rolling to a thickness of 3 mm and cold rolling to 1 mm without intermediate annealing, final annealing was performed (some samples were not subjected to final annealing). Tables 2 and 3 show the homogenizing heat treatment conditions, the hot rolling finish temperature, and the final annealing conditions for these samples. Further, with respect to these samples, the area occupation rate of the Fe-based intermetallic compound having a major axis of 0.5 μm or more on the plate surface was measured, and the results are also shown in Tables 2 and 3. Further, the electrical conductivity (Ea) of the above sample and the electrical conductivity Eb after annealing the sample at 450 ° C. for 4 hours were measured, and the difference (Eb−Ea) between them was measured.
Is also shown in Tables 2 and 3.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

Next, the sample thus obtained is subjected to alkaline degreasing and etching treatments in a conventional manner,
With an electrolytic bath having a sulfuric acid concentration of 15 vol%, a temperature of 20 ° C,
Film thickness is about 20 μm under the condition of current density of 1.5 A / dm ^2.
Was subjected to electrolytic treatment to form an alumite film on the surface of the sample. Then, after performing a sealing treatment with pure water boiling water, the appearance color tone was visually observed, and the color difference was measured with a color difference meter. The results are shown in Tables 4 and 5. The color difference meter is a model CDE-C manufactured by Suga Test Instruments Co., Ltd.
H-1M was used. In the table, the L value indicates the lightness, the a value indicates the red system when the + value is, the green system when the-value is, and the b value is
A + value indicates a yellow system, and a-value indicates a blue system. In the case of the aluminum alloy material having a reddish beige color this time, a
The + value of the value increases.

[0023]

[Table 4]

[0024]

[Table 5]

As is apparent from Tables 1 and 2, examples of the present invention in which the alloy composition is within the scope of the invention of Claim 1 of the present application and the manufacturing method is within the scope of the inventions of Claims 2 to 4 of the present application. No.
1 to 8 are all Fe having a major axis of 0.5 μm or more
The area occupation rate of the intermetallic compounds on the plate surface is 0.1 to
0.3%, and its electric conductivity Ea is 4%.
The difference (Eb-Ea) from the electrical conductivity Eb when annealed at 50 ° C. for 4 hours is 5% IACS or more, which satisfies the metallurgical structure defined by the invention of claim 1 of the present application. When these aluminum alloy materials are anodized, as shown in Table 4, a uniform, reddish beige color is exhibited.

On the other hand, even if the alloy composition is within the scope of the invention of claim 1 of the present application, the production methods are outside the scope of the inventions of claims 2 to 4 of the present invention. Comparative Example 15 in which the alloy composition is outside the scope of the invention of Claim 1 of the present application even within the scope of the inventions of Claims 2 to 4 of the present application
As is clear from Tables 1 and 3, Nos. 20 to 20 do not satisfy the metallographic structure defined by the invention of claim 1 of the present application.
When these aluminum alloy materials are subjected to alumite treatment, as is clear from Table 5, the alumite coating becomes blackish brown or blackish, yellowish gray, or grayish, and uniform in the characteristic of the present invention. An aluminum alloy material having a reddish beige color cannot be obtained.

[0027]

As described above, according to the present invention,
It is possible to obtain a uniform and sufficiently reddish beige colored alumite film with good reproducibility.
It can be sufficiently applied to products requiring decorativeness such as containers and ornaments, and has a remarkable industrial effect.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinobu Kamata 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (4)

[Claims] 1. At least Mn of 1.0 to 1.6 wt.
%, Fe 0.3 to 1.0 wt%, Cu 0.01 to 0.1
An aluminum alloy material containing 0.2% by weight of Si and 0.2% by weight or less of Si with the balance being aluminum, and the area occupation rate of the Fe-based intermetallic compound having a major axis of 0.5 μm or more on the plate surface is 0.1. .About.0.3%, and the conductivity Ea is smaller than the conductivity Eb when the material is annealed at 450.degree. C. for 4 hours, and the difference in conductivity (Eb
-Ea) is an aluminum alloy material for reddish beige colored alumite characterized by being 5% IACS or more. 2. A method of performing homogenizing heat treatment at a temperature of 550 ° C. or higher for 3 hours or more, then performing hot rolling at an end temperature of 320 ° C. or lower, and performing cold rolling without intermediate annealing. The method for producing an aluminum alloy material for reddish beige coloring alumite according to claim 1. 3. After homogenizing heat treatment at a temperature of 550 ° C. or higher for 3 hours or more, hot rolling at an end temperature of 320 ° C. or lower is performed, and cold rolling is performed without intermediate annealing.
B) 400 to 600 ° C at a heating rate of 100 ° C / min or more
And hold at that temperature for less than 1 minute, then 200 ℃
The reddish beige according to claim 1, wherein the final annealing is performed at a cooling rate of 100 ° C / min or more until the following, or b) the final annealing is performed at a temperature of less than 280 ° C for less than 10 hours. A method for producing an aluminum alloy material for coloring alumite. 4. When homogenizing heat treatment is performed at a temperature of 550 ° C. or higher for 3 hours or more, hot rolling is performed, and then cold rolling is performed, during or after the completion of cold rolling, 55
Maintaining a temperature of 0 ° C or more for 10 minutes or more reduces annealing
The method for producing an aluminum alloy material for reddish beige colored alumite according to claim 1, which is performed once.