JP3078607B2 - Method for producing aluminum alloy plate for anodizing treatment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy plate used for anodizing treatment, for example, a building material such as a curtain wall and an outer wall of a building, a roof, a door, a gate, an interior material, and various other objects. The present invention relates to a method for producing an aluminum alloy plate used for a container, a nameplate or the like.

[0002]

2. Description of the Related Art In general, curtain walls and building exterior materials,
Rolled materials of aluminum alloy used for building materials such as interior materials, or for objects, containers, nameplates, etc. are often used after being subjected to anodizing treatment from the viewpoint of corrosion resistance. Many aluminum alloys for anodizing for these uses have a color tone from light gray to silver after anodizing, and rolled materials of such alloys are generally JIS.
In many cases, 1050 alloy, 1100 alloy, 5005 alloy, and the like are used. Al-1 to gray
A 4% Si alloy is common.

[0003]

SUMMARY OF THE INVENTION Recently, building exterior materials,
In applications such as interior materials, diversification and individualization of color tone are often required due to design requirements.
For an aluminum alloy used after being subjected to anodizing treatment, various colors are often required in these applications, and examples thereof include a golden color and a dark green-gray color.

As a method for giving various colors to the anodized aluminum alloy material, there are a secondary electrolytic method, a dyeing method, and other coating methods. However, these methods have problems of fading, corrosion resistance, and corrosion resistance. There are problems such as cost. Therefore, it is desired to obtain a golden color or a dark green-gray color tone while maintaining the anodizing treatment.

Conventionally, as a method of obtaining a golden or dark green-gray color tone with an anodic oxidation treatment, there is an anodic oxidation treatment with an oxalic acid electrolytic bath. Compared with the case of occupying sulfuric acid electrolytic bath, strictness is required for electrolytic conditions and electrolytic bath management,
Further, since the film properties are inferior and the cost is high, it is desired to obtain a golden or dark green-gray color tone with the anodic oxidation treatment using a sulfuric acid electrolytic bath.

However, in the prior art, a method for obtaining a golden or dark green-gray color tone with an anodic oxidation treatment using a sulfuric acid electrolytic bath has not been established. In particular, when a method of directly casting a plate of about 5 to 50 mm by a plate continuous casting method (continuous casting rolling method) is applied, in order to obtain a golden or dark green-gray color while anodizing with a sulfuric acid electrolytic bath. It is the fact that the method was not known.

[0007] In addition, building materials and the like are required not only to have a simple color tone but also to have a unique appearance from the viewpoint of design. One of them is a horizontal stripe pattern. The fact is that a technique for stably obtaining a predetermined regular horizontal stripe pattern while the oxidation treatment has not been established has been established.

The present invention has been made in view of the above circumstances, and has a golden or dark green-gray color tone and is orthogonal to a casting direction or a rolling direction while being subjected to anodic oxidation treatment in a sulfuric acid electrolytic bath. It is an object of the present invention to provide an aluminum alloy plate capable of reliably and stably obtaining a plate having horizontal stripes in different directions.

[0009]

[0010]

[0011]

The method for producing an aluminum alloy plate for anodizing according to the present invention is basically based on the premise that the component system of the alloy is an Al-Cr system and a predetermined amount of Fe is added. In addition, by effectively utilizing the characteristics of the continuous plate casting method that directly casts a plate, horizontal stripes are generated on the surface after the anodizing treatment with the sulfuric acid electrolytic bath, and the anodizing treatment with the sulfuric acid electrolytic bath remains as it is. The color tone is golden or dark green-grey. and again,
It is intended to provide a plate that has been subjected to cold rolling after continuous plate casting or a plate that has been reduced in thickness by continuous rolling.

More specifically, the production method according to the first and second aspects of the present invention is a method for producing an aluminum alloy plate for anodizing treatment which has a particularly golden tone and horizontal stripes after the anodizing treatment. Wherein the method of claim 1 comprises Cr 0.3-1.2 wt%, Fe over 0.2 wt%, 1.0 wt% or less, Si 0.5 wt% or less, and a grain refiner. 0.005 to 0.15 wt
% Alone or in combination with 0.0001 to 0.0500 wt% of B, the balance of which is composed of Al and other unavoidable impurities.
The casting is performed at a cooling rate of / sec or more.

Further, according to a second aspect of the present invention, there is provided a method of manufacturing a molten alloy having the same composition as described above by a continuous casting method at 5 ° C. /
After casting at a cooling rate of sec or more, or after the casting, heating is performed at 300 to 400 ° C. for 0.5 to 24 hours, and then cold rolling is performed.

On the other hand, the production method according to each of the third and fourth aspects of the present invention relates to a method for producing an aluminum alloy for anodizing treatment having a particularly dark green-gray color tone and a horizontal stripe pattern after the anodizing treatment. In the method according to the third aspect of the present invention, the molten metal of the alloy having the same composition is cast by a continuous casting method at a cooling rate of 5 ° C./sec or more, and then exceeds 400 ° C. and 630 ° C. or less. 0.5 ~ 2 at the temperature of
It is characterized by heating for 4 hours.

[0015] The method of the invention according to claim 4 is that the molten alloy having the same composition as the above is melted at 5 ° C. /
After casting at a cooling speed of at least sec, cold rolling is performed, and before, during or after the cold rolling, at 400 ° C.
And heating at a temperature of not more than 630 ° C. for 0.5 to 24 hours.

[0016]

First, the reasons for limiting the composition of the aluminum alloy in the present invention will be described.

Cr: If Cr is present in a solid solution state, a golden color can be developed as a color tone after anodizing treatment. Also, when a dark green-gray color is developed as a color tone after the anodizing treatment, a golden color by solid solution Cr is indispensable as a base color tone of the dark green-gray color tone. That is, based on the golden color of the film, the Al-Fe
As a result of the (-Si-Cr) -based fine precipitates turbidizing the golden color, a deep dark green-gray color tone is obtained. Therefore, Cr is an essentially important alloying element both in obtaining a golden color tone and in obtaining a dark green-gray color tone in the present invention. The greater the solid solution amount of Cr, the stronger the golden color. However, in order to obtain a sufficient golden color tone, Cr of 0.3 wt% or more is usually required. However, in a casting method with a slow cooling rate, such as a DC casting method, when Cr is 0.3 wt% or more, a huge Cr-based primary intermetallic compound is crystallized, and not only cannot be substantially produced, but also Cr is forcibly forced. Because of the inability to form a solid solution, a golden color cannot be developed clearly. On the other hand, by rapid solidification at a cooling rate of 5 ° C./sec or more by a continuous plate casting method or the like, the Cr content range in which a coarse Cr-based intermetallic compound is not generated can be increased to 1.2 wt%. In addition, in rapid solidification such as a continuous plate casting method, most of the added Cr can be forcibly dissolved in a solid solution, so that a sufficiently strong golden color can be developed. However, if the Cr content exceeds 1.2 wt%, a coarse crystal of primary crystals is crystallized even when the continuous casting method is applied, and the amount of forced solid solution of Cr reaches the limit, so it is meaningless to add more. . Therefore, the Cr content is set in the range of 0.3 to 1.2 wt%.

Fe: In the present invention, Fe contributes to exhibit a horizontal stripe pattern after anodizing treatment, and when subjected to an appropriate heat treatment, contributes to change the color tone from golden to dark green-gray. That is, if Fe is contained, Al—Fe (−
Si-Cr) crystallized substances are crystallized, and this Al-Fe
The (-Si-Cr) crystallized substance makes the golden color tone slightly turbid. In particular, if the Al-Fe (-Si-Cr) crystallized material is large and coarsely distributed, the coarsely distributed portion will exhibit a slightly different color tone from the other portions. In the continuous casting method in which hot water is cast between a pair of rotating cooling rolls, or caterpillars, or belts, a pulsation occurs in the cooling rate during casting, as will be described later. If it exceeds, the pulsation of the cooling rate at the time of casting described above causes Al-Fe (-Si-Cr) -based crystallization to be alternately and densely distributed in the casting direction.
A unique horizontal stripe pattern perpendicular to the casting direction can be generated on the plate surface after the anodizing treatment. On the other hand, if Al-Fe (-Si-Cr) -based precipitates are finely precipitated by performing an appropriate heat treatment, a dark green-gray turbidity is added to the golden color of the base, thereby increasing the depth of darkness. A green-gray shade is obtained. Also in this case, as described above, in the continuous plate casting method, when the Fe content exceeds 0.2 wt%, the crystallization of the Al-Fe (-Si-Cr) -based crystals alternately and densely and densely in the casting direction due to the pulsation of the cooling rate. , And not only that, but in response to the pulsation of the cooling rate, Fe, C
The amount of forced solid solution such as r also changes alternately in the casting direction, so that the distribution form of Al-Fe (-Si-Cr) -based precipitates due to the heat treatment changes corresponding to the change in the amount of forced solid solution. Thereby, a horizontal stripe pattern in dark green gray is achieved. here,
If the amount of Fe is 0.2 wt% or less, Al-Fe (-Si
The amount of crystallization of -Cr) -based crystallization is insufficient, making it difficult to obtain a horizontal stripe pattern. In addition, Al-Fe (-S
Fine precipitates of the (i-Cr) type are also reduced, and it is also difficult to obtain a dark green-gray color tone. On the other hand, Fe content is 1.0 wt%
If it becomes above, casting will become difficult. Therefore, the amount of Fe needs to be more than 0.2 wt% and 1.0 wt% or less.

Si: If Si is contained together with Fe,
Al-Fe-Si (-Cr) -based crystallized substances are crystallized, and if appropriate heat treatment is performed, fine Al-Fe-Si (-C
r) precipitates are deposited. Al-Fe-Si (-C
As described for Fe, the crystallized substances of the r) system are alternately and densely distributed in the casting direction due to the pulsation of the cooling rate during continuous casting, and generate horizontal stripes. In addition, fine Al-Fe
As described above, the -Si (-Cr) -based precipitate contributes to the development of a dark green-gray color. Therefore, Si has the effect of promoting the appearance of horizontal stripes and the development of dark green-gray. However, if the Si content exceeds 0.5 wt%, casting becomes difficult, so the Si content must be 0.5 wt% or less.

Ti, B: Adding a small amount of Ti alone or combining a small amount of Ti with a small amount of B is effective for refining ingot crystal grains. In particular, in the continuous plate casting method applied in the present invention, the refinement of ingot crystal grains has an effect of preventing casting defects such as segregation and exudation of a solute element due to the segregation and oxidation of the solute element. Regardless of the casting method, the refinement of the ingot crystal grains results in uniform and fine dispersion of the crystallized compound, so that it is possible to prevent the occurrence of color unevenness other than the pattern, and as a result, it has the effect of developing a stable horizontal stripe pattern. In addition, especially when a dark green-gray color tone is obtained, C
golden color by solid solution of r and Al-Fe (-Si-Cr)
The turbidity due to the fine precipitates of the system is synthesized to achieve a dark green-gray color tone, and the horizontal stripe pattern of the color is formed by utilizing the pulsation of the cooling rate of the continuous casting of the Al-Fe (-Si −
This is achieved by periodically varying the distribution of Cr) -based precipitates. However, it is known that the precipitation behavior of precipitates differs depending on the crystal orientation.If the crystal grains at the time of casting are coarse, the distribution of precipitates differs for each crystal grain, and another pattern derived from the crystal grain shape Will occur. Although a pattern derived from such a crystal shape is also an interesting pattern, in order to obtain a horizontal stripe pattern intended in the present invention, particularly a horizontal stripe pattern of dark green gray, a fine crystal structure is prepared in a casting stage. There is a need. If Ti is less than 0.005 wt%, the effect of refining ingot crystal grains cannot be obtained, and Ti is 0.15 wt%.
If it exceeds 1, primary crystal TiAl ₃ is crystallized and the surface characteristics are impaired, so Ti was set in the range of 0.005 to 0.15 wt%. When B is added together with Ti, the B content is 0.0
If the content of B is less than 001 wt%, the effect of adding B cannot be obtained. On the other hand, if the B content exceeds 0.0500 wt%, coarse particles of TiB ₂ are mixed and surface defects are caused.
It was within the range of 500 wt%.

Other than the above components, basically, Al
And unavoidable impurities. However, in a normal aluminum alloy, a small amount of Be may be added in order to prevent oxidation of the molten metal during casting. However, in the case of the alloy of the present invention, a small amount of Be may be added. If the amount is less than about 500 ppm, no other performance is degraded. In addition, for the purpose of improving strength, C
Any one or more of u, Zn, and Mg may be contained. Cu is 1.0 wt% or less, Zn is 2.0 wt% or less, and Mg is 2.0 wt% or less. The object of the present invention can be achieved without impairing other performances. However, Cu and Zn are each preferably less than 0.1 wt% from the viewpoint of corrosion resistance, and Mg easily forms an oxide, and inclusions resulting therefrom adversely affect the surface quality after the surface treatment. 0.1% by weight of Mg
Less than is preferred.

Next, a method for producing the aluminum alloy of the present invention will be described.

In the method of the present invention, as a method of casting a molten alloy, the plate is directly cast by supplying the molten metal between a pair of rotary cooling rolls, caterpillars, belts, and the like.
Apply the continuous plate casting method. This is known as, for example, the 3C method, the Hunter method, the caster II, or the Hatherley method, and is also called a roll cast or a strip cast. In such a continuous plate casting method, for example, when the molten metal contacts the rotating cooling roll, the position where the molten metal contacts the rotating cooling roll surface fluctuates periodically due to the effect of surface tension, and as a result, the cooling rate also fluctuates periodically. . For this reason, a pattern called a ripple mark easily occurs. However, in the present invention, the periodic fluctuation (pulsation) of the cooling rate is effectively used, and a stable horizontal stripe pattern is formed by combining with an appropriate alloy component composition. Color to dark green-gray tones are obtained.

In the method of the present invention, in casting a molten alloy having the above-described composition, the solid color which contributes to the golden color development (or the golden color development serving as a dark green-gray base) by anodizing treatment. In order to ensure sufficient molten Cr, Cr is forcibly dissolved and 0.3% or more of C
A cooling rate of 5 ° C./sec or more is required in order not to generate a coarse Cr-based intermetallic compound even with the amount of r. In order to obtain such a cooling rate at the time of casting with an industrially large plate, a molten metal is supplied between a pair of cooling rolls, caterpillars, belts and the like as described above, and a plate of 5 to 50 mm is directly cast. It can be achieved by a continuous plate casting method (continuous casting rolling method).

The cast sheet thus obtained by the continuous casting method may be subjected to anodizing treatment with the same thickness, or may be subjected to cold rolling to a required thickness before being subjected to anodizing treatment. May be served. However, in particular, when obtaining a horizontal stripe pattern in a dark green-gray color tone, it is necessary to perform a predetermined heat treatment at any stage after casting. That is, in order to obtain a deep dark green-gray color tone by adding Al-Fe (-Si-Cr) -based fine precipitates based on the golden color of solid solution Cr as a color tone after the anodizing treatment. It is necessary to perform heat treatment at a relatively high temperature immediately after casting, or in the case of performing cold rolling, during or after cold rolling. On the other hand, in the case of obtaining a horizontal stripe pattern with a golden color tone, heat treatment is not an essential condition, but for the purpose of homogenizing the cast plate, or for the purpose of facilitating cold rolling, and further for the purpose of strength adjustment, etc., immediately after casting, Alternatively, heat treatment (annealing) may be performed during the cold rolling or after the cold rolling.

The heat treatment conditions will be described below.

As described above, when a horizontal stripe pattern having a dark green-gray color tone after the anodizing treatment is obtained, Al-Fe (-Si-
Heat treatment for precipitating fine Cr) -based precipitates must be performed at any stage after casting. If the heating temperature in this case is 400 ° C. or lower, the precipitation of Al—Fe (—Si—Cr) -based precipitates contributing to the formation of dark green-gray is insufficient, the golden color is still strong, and the dark green-grey with deepness It can not be said. On the other hand, if the temperature exceeds 630 ° C., the color tone becomes thinner as a whole, and secondary recrystallization occurs to roughen the surface. On the other hand, if the heating time is less than 0.5 hour, the precipitation is insufficient, while if it exceeds 24 hours, the effect is saturated and the economy is only lost. Therefore, the heat treatment in this case exceeds 400 ° C.
It is necessary to heat to a temperature of 30 ° C. or lower for 0.5 to 24 hours. As described above, the heat treatment for precipitating Al-Fe (-Si-Cr) -based fine precipitates to obtain a dark green-gray color tone may be performed after casting when using a cast plate as it is.
When cold rolling is performed, it may be before, during, or after cold rolling. When heat treatment is performed during or after cold rolling, it is preferable to perform the heat treatment at a temperature of 600 ° C. or lower because secondary recrystallization is likely to occur.

On the other hand, when a horizontal stripe pattern having a golden color tone is obtained after the anodizing treatment, the heat treatment is not essential. However, in order to facilitate homogenization and cold rolling of the cast plate or to adjust the strength, the heat treatment is performed. (Annealing) may be performed. However,
In this case, the heat treatment needs to be performed at a relatively low temperature so as not to deviate from the golden color tone. Further, the condition is slightly different between the case where the heat treatment is performed at the stage of the cast plate and the case where the heat treatment is performed during or after the cold rolling as follows.

First, the heating performed at the stage of the cast plate is carried out for the purpose of relaxing segregation during casting and homogenizing it, and when performing cold rolling thereafter, for the purpose of facilitating subsequent cold rolling. In this case, if the temperature is lower than 300 ° C., segregation at the time of casting cannot be alleviated.
(-Si-Cr) -based fine precipitates are formed, and the color tone after the anodizing treatment becomes dark green-gray. The time is 0.
If the time is less than 5 hours, the effect of the heat treatment is not obtained, while if it exceeds 24 hours, the effect is saturated and the economical efficiency is only lost. Therefore, when a horizontal stripe pattern having a golden color tone is obtained, the heating performed at the stage of the cast plate requires 0.5 to 500 ° C. within the range of 300 to 400 ° C.
~ 24 hours.

The heat treatment (intermediate annealing or final annealing) performed during or after the cold rolling is performed for the purpose of facilitating the subsequent cold rolling and adjusting the strength. For the heat treatment in this case, either batch annealing or continuous annealing may be used.

In the case of batch annealing, the temperature is selected in accordance with the desired strength. However, if the temperature is lower than 300 ° C., the effect of the annealing cannot be obtained.
(-Si-Cr) -based fine precipitates are generated, and a golden color tone cannot be obtained.
If the time is less than 10 hours, the effect of annealing cannot be obtained. On the other hand, if the time exceeds 12 hours, fine precipitates of an Al—Fe (—Si—Cr) system may be generated even at 400 ° C. or lower. Therefore, in the case of obtaining a horizontal stripe pattern having a golden color tone, when applying batch annealing to annealing performed during or after cold rolling, a temperature in the range of 300 to 400 ° C. and 0.5 to 12 ° C.
Hold for a long time.

On the other hand, in the case of continuous annealing, since the coil is annealed while being continuously unwound, the treatment is generally performed at a higher temperature and in a shorter time than in batch annealing. And in this case,
Since heating is performed for a short time even at a high temperature, Al-Fe
No fine precipitate of (-Si-Cr) system is generated. Therefore, the heating temperature is not limited in terms of color tone, and may be selected for the purpose of strength adjustment or the like. However, if the temperature is less than 400 ° C., the effect of annealing cannot be obtained. If the temperature exceeds 650 ° C., eutectic melting occurs. If the holding time exceeds 3 minutes, the crystal grains may be coarsened at a high temperature. Therefore, when it is desired to obtain a horizontal stripe pattern with a golden color tone, annealing performed during or after cold rolling by continuous annealing is 400 to 6
No holding at a temperature of 50 ° C. or holding for 3 minutes or less.

In the case of obtaining a horizontal stripe pattern having a dark green-gray color tone, a heat treatment for fine precipitation for obtaining a dark green-gray color tone at any stage after casting, as described above,
In other words, it is essential to perform a heat treatment at 400 ° C. or more and 630 ° C. or less × 0.5 to 24 hours. However, such a heat treatment for the color tone is a heat treatment for other purposes, ie, homogenization of casting and subsequent heat treatment. The heat treatment may be performed to facilitate the cold rolling or for the purpose of adjusting the strength. Further, heat treatment for a purpose other than the color tone may be performed in a step different from the heat treatment for the color tone. In this case, the heat treatment (annealing) for a purpose other than the color tone may deviate from the condition of the heat treatment for the color tone, and the condition can be selected according to the purpose.

Specifically, when the cast sheet is subjected to heat treatment (annealing) for purposes other than color tone, that is, for the purpose of relaxing segregation during casting to homogenize and facilitating cold rolling, As the condition, heating and holding at a temperature in the range of 300 to 400 ° C. for 0.5 to 24 hours may be performed. Temperature 3
If the temperature is lower than 00 ° C., the above-mentioned effects cannot be obtained, while if the temperature exceeds 400 ° C., the crystal grains become coarse. The heating time is 0.
If the time is less than 5 hours, the above-mentioned effects cannot be obtained. On the other hand, if the time exceeds 24 hours, the effects are saturated and only the economic efficiency is impaired.

On the other hand, during the cold rolling or after the cold rolling,
As a heat treatment (annealing) performed for the purpose other than the color tone, that is, for facilitating the subsequent cold rolling and for the purpose of adjusting the strength, any of a batch type annealing and a continuous annealing may be applied. In the case of the formula annealing, the effect of annealing cannot be obtained at a temperature lower than 300 ° C., whereas at a high temperature exceeding 550 ° C., secondary recrystallization occurs and the crystal becomes coarse. Effect is not obtained,
On the other hand, if the time exceeds 12 hours, the effect is saturated and only the economic efficiency is impaired. Therefore, when batch annealing is applied to annealing performed during or after cold rolling for purposes other than color tone, heating and holding at a temperature within the range of 300 to 550 ° C. for 0.5 to 12 hours may be performed. On the other hand, in the case of continuous annealing, the effect of annealing cannot be obtained if the temperature attained by heating is less than 400 ° C., and if it exceeds 650 ° C., eutectic melting may occur, and if the holding time exceeds 3 minutes. At a high temperature, the crystal grains may be coarsened. Therefore, when continuous annealing is applied to annealing performed during or after cold rolling for purposes other than color tone, the temperature may be maintained at 400 to 650 ° C. without holding or holding for 3 minutes or less.

To summarize the above, the amount of Cr is 0.3-1.
If the content of Fe is within the range of 2 wt% and the Fe content is more than 0.2 wt% and not more than 1.0 wt%, no heat treatment is performed after the rapid cooling casting by the continuous sheet casting method, or the heat treatment is relatively performed. If the annealing is performed at a low temperature for a long time (300 to 400 ° C. × 0.5 to 24 hours) or continuous annealing, a plate having a horizontal tone with a golden color after the anodizing treatment can be obtained. If the heat treatment is performed at least once for a long time (more than 400 ° C. and less than 630 ° C. × 0.5 to 24 hours), it is possible to obtain a plate having a horizontal stripe pattern in a dark green-gray color after the anodizing treatment. In this case, if the above heat treatment is performed at least once, the color tone will not be changed even if a heat treatment other than the above-mentioned condition is performed.

Next, the aluminum alloy (cast plate or rolled plate) obtained by the above-described method is subjected to anodizing treatment to obtain a plate having horizontal stripes in a golden to dark green-gray tone. The process for obtaining it will be described.

In the anodic oxidation treatment, degreasing and etching are generally performed to remove surface dirt and surface defects in advance. Usually, caustic soda-based alkaline etching is performed. Then, the anodic oxidation treatment itself is performed when the H ₂ SO ₄ concentration is 10%.
An anodic oxide film having a film thickness of 10 to 30 μm is formed by using a sulfuric acid bath having a bath temperature of 10 to 30 ° C., a current density of 1.5 A / dm ² or more and less than 2.5 A / dm ² using a sulfuric acid bath of 25 vol%.

Here, the H ₂ SO ₄ concentration of the sulfuric acid bath is 10 v
If the amount is less than ol%, the porosity of the formed anodic oxide film decreases, and the bath voltage increases. On the other hand, the H ₂ SO ₄ concentration was 25 vol%
If it exceeds, the surface becomes rough and the anodic oxide film becomes soft. If the bath temperature is lower than 10 ° C., it takes a long time to obtain a required film thickness, which is uneconomical. On the other hand, if the bath temperature is higher than 30 ° C., the corrosion resistance after the anodic oxidation treatment is reduced. Further, when the current density is 2.5 A / dm ² or more, a large amount of electric power is required for processing, which is not practical. On the other hand, when the current density is less than 1.5 A / dm ² , the color tone after the anodizing treatment becomes thin and a strong golden color Or dark green-grey cannot be obtained. If the thickness of the anodic oxide film formed is less than 10 μm, sufficient corrosion resistance cannot be obtained, while increasing the thickness to more than 30 μm is not economical.

By the anodic oxidation treatment in the sulfuric acid bath as described above, a horizontal stripe pattern having a golden to dark green-gray color tone can be obtained.

The horizontal stripe pattern obtained by the present invention is shown in FIG.
As shown in the figure, a striped pattern in a direction perpendicular to the casting direction and the rolling direction, and a relatively dark colored striped portion on a relatively light-colored ground portion 1 in a straight or wavy or curved shape. Portion 2 is a striped pattern that exists substantially perpendicular to the casting direction and the rolling direction. The width (width between centers of the striped portions 2) W of the horizontal stripes is usually about 1 to 2 mm in the width of a cast plate, and the width of the horizontal stripes is widened in a rolled plate according to the amount of reduction. Become.

[0042]

【Example】

Example 1 An aluminum alloy having a component composition shown in alloy numbers 1 to 5 in Table 1 was melted according to a conventional method, and a cast plate having a thickness of 7 mm was obtained by a continuous plate casting method in which hot water was supplied between a pair of rolls. . The cooling rate during solidification is 200 to 300 ° C / se
c. Each of the obtained alloys is subjected to an anodic oxidation treatment as it is (as cast) or 350 ° C. × 1
After heating for 0 hour or 550 ° C. × 10 hours, anodizing treatment was performed.

In any of the above cases, the anodic oxidation treatment was performed under the following conditions. That is, first, 10% NaO
After etching with H aqueous solution, washing with water and desmutting with nitric acid are performed, and then anodizing treatment is performed using a 15 vol% sulfuric acid bath at a bath temperature of 20 ° C. and a current density of 1.5 A / dm ² , An anodized film of 20 μm was formed.

The color tone and the state of the horizontal stripe pattern on the surface of each plate subjected to the anodic oxidation treatment as described above are visually observed.
Table 2 shows the results of the determination. In Table 2, a circle in the horizontal stripe pattern column indicates a case where the horizontal stripe pattern clearly appeared, a mark Δ indicates a case where the horizontal stripe pattern was blurred, and a cross mark indicates the case where the horizontal stripe pattern did not occur. It represents.

[0045]

[Table 1]

[0046]

[Table 2]

As is evident from Table 2, among the cast sheets (manufactured symbols A to E) cast by a continuous sheet casting method using alloys (alloy numbers 1 and 2) whose component compositions fall within the range of the present invention, The as-prepared plates (Production Codes A and D) and the plate heated at 350 ° C. × 10 hours (Production Code B) can develop a golden-colored horizontal stripe pattern by anodizing treatment. The plate (production code C, E) heated at 10 ° C. × 10 hours was able to develop a dark green-gray horizontal stripe pattern by anodizing treatment. On the other hand, when an alloy (alloy number 3) having both a small Cr content and a small Fe content (manufacturing code F, G) is used, sufficient golden and dark green-gray tones are obtained even when the continuous plate casting method is applied. No horizontal stripes were clearly observed. When an alloy having a low Fe content (alloy No. 4) was used (manufacturing codes H and I), a golden color tone was obtained, but no horizontal stripe pattern was exhibited.
Further, in the case of using an alloy to which Ti was not added (alloy No. 5) (manufacturing code J), a dark green-gray color tone was obtained by heating at 500 ° C. × 10 hours, but no horizontal stripe pattern appeared. Was.

Example 2 Each of the alloys Nos. 1 to 5 of Example 1 was cast into a 7 mm thick cast plate by continuous continuous casting in the same manner as described above, and each cast plate (as cast) was 1.5 mm thick. Until cold-rolled. A part of each plate after cold rolling is subjected to anodizing treatment as it is, and others are subjected to annealing in a batch furnace at 300 ° C. × 5 hours or 500 ° C. × 5 hours, or a salt bath assuming continuous annealing. After annealing at 450 ° C. × 10 sec, an anodic oxidation treatment was performed. The conditions of the anodizing treatment are the same as those in the first embodiment. The color tone and horizontal stripe pattern of the surface after the anodizing treatment were visually observed and judged. Table 3 shows the results.

[0049]

[Table 3]

As is apparent from Table 3, even when cold rolling is performed, of the alloys within the component composition range of the present invention,
In particular, the plate not subjected to annealing, the plate subjected to annealing at 300 ° C. for 5 hours, and the plate subjected to annealing assuming continuous annealing all obtained a golden horizontal stripe pattern,
Each of the plates annealed at 5 ° C. for 5 hours was able to obtain a dark green-gray horizontal stripe pattern.

[0051]

[0052]

According to the method for producing an aluminum alloy of the present invention, an aluminum alloy having a golden or dark green-gray color tone and exhibiting a horizontal stripe pattern can be reliably and easily obtained by anodizing treatment in a sulfuric acid bath. In particular, the color tone after the anodic oxidation treatment can be easily changed between golden and dark green-grey depending on the presence or absence of heat treatment or the change in the condition of the heat treatment.

Therefore, the present invention is useful when applied to various building materials, nameplates, various objects, containers, and the like that require diversification and individualization of appearance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a horizontal stripe pattern after an anodizing treatment of an aluminum alloy plate according to the present invention.

[Explanation of symbols]

 1 Ground part 2 Striped part

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI C22F 1/00 613 C22F 1/00 613 623 623 671 671 681 681 686 686A 691 691B 691C (56) reference JP Akira 59-56558 (JP, A) JP-A-3-100144 (JP, A) JP-A-53-43016 (JP, A) JP-A-62-275546 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) C22F 1/04-1/057 C25D 11/04-11/24 C22C 21/00-21/18

Claims (4)

(57) [Claims] 1. Cr 0.3-1.2 wt%, Fe 0.2 wt
% And not more than 1.0 wt% and not more than 0.5 wt% of Si, and Ti
0.15wt% alone or B 0.0001-0.05
After the anodizing treatment, the molten metal of the alloy containing in combination with Al and other inevitable impurities is cast at a cooling rate of 5 ° C./sec or more by the continuous casting method. A method for producing an aluminum alloy plate for anodic oxidation treatment having a golden color tone and having a horizontal stripe pattern. 2. Cr 0.3-1.2 wt%, Fe 0.2 wt
% And not more than 1.0 wt% and not more than 0.5 wt% of Si, and Ti
0.15wt% alone or B 0.0001-0.05
After the molten alloy of the alloy containing Al and other unavoidable impurities is cast at a cooling rate of 5 ° C./sec or more by the continuous plate casting method, or 300% after the casting. 0.5-2 at 400 ° C
A method for producing an anodized aluminum alloy sheet having a golden color tone and a horizontal stripe pattern after anodizing, comprising heating for 4 hours and then cold rolling. 3. Cr 0.3-1.2 wt%, Fe 0.2 wt
% And not more than 1.0 wt% and not more than 0.5 wt% of Si, and Ti
0.15wt% alone or B 0.0001-0.05
An alloy melt containing at least 100 wt% and the balance consisting of Al and other unavoidable impurities was cast at a cooling rate of 5 ° C./sec or more by a continuous plate casting method.
A method of producing an anodized aluminum alloy plate having a dark green-gray color tone and a horizontal stripe pattern after anodizing, wherein the plate is heated at a temperature of not lower than 630 ° C and not higher than 630 ° C for 0.5 to 24 hours. . 4. Cr 0.3-1.2 wt%, Fe 0.2 wt
% And not more than 1.0 wt% and not more than 0.5 wt% of Si, and Ti
0.15wt% alone or B 0.0001-0.05
A molten alloy containing Al and other inevitable impurities is cast at a cooling rate of 5 ° C./sec or more by a continuous sheet casting method, and then cold-rolled. Before, during or after the cold rolling, at a temperature of more than 400 ° C and 630 ° C or less, 0.5 to 24
A method for producing an aluminum alloy plate for anodizing treatment, which has a dark green-gray color tone and has a horizontal stripe pattern after the anodizing treatment, characterized by heating for an hour.