JP5640399B2 - Aluminum alloy plate with anodized film and method for producing the same - Google Patents

Description

  The present invention relates to an aluminum alloy plate having a light green and white anodized film and a method for producing the same.

  The Al—Mg-based alloy sheet is subjected to intermediate annealing in the process of making the sheet, and is subjected to cold rolling and annealing in order to impart required mechanical characteristics. However, after cold working, the alloy of this type is naturally softened and the strength is not stabilized, so that stabilization annealing may be performed after cold rolling as necessary.

  The aluminum alloy plate is anodized with a sulfuric acid bath, and the surface has a color tone peculiar to the alloy, and it is used for electrical and electronic equipment such as architectural interior and exterior panels, equipment, home appliances, digital cameras and PCs. Yes. For example, a JIS 5052 alloy plate that is a non-heat-treatable alloy and has low residual strain and good processing accuracy develops a yellowish color tone by anodizing with a sulfuric acid bath. This color tone is considered to be caused by Cr in the alloy added for recrystallized grain refinement or the like, and when it dislikes the yellow color, an aluminum alloy plate containing no Cr is added.

  Japanese Patent Application Laid-Open No. 9-143602 discloses an Al—Mg-based alloy plate containing 0.10 to 0.30% of Mn with Cr as an impurity of 0.02% or less.

Japanese Patent Laid-Open No. 9-143602

  The present invention is an Al-Mg based alloy plate, which contains Cr for recrystallization grain refinement. However, if Cr is contained, an anodizing treatment with a sulfuric acid bath gives a strong yellowish tinge, and an aluminum alloy plate that develops a white color cannot be obtained, and the use of the plate is limited.

  That is, the present invention provides an aluminum alloy plate that can suppress yellowish color development as much as possible even when anodized with a sulfuric acid bath, and that develops a pale greenish white color that does not have a reddish taste, and a method for producing the same. Objective.

  The inventors have obtained the knowledge that the yellowish coloring in the Al-Mg alloy plate containing Cr is due to the Cr-containing intermetallic compound produced in the plate making process including casting, and the present invention Was completed.

  That is, the present invention is as follows (1) to (4).

Mg 2.0-3.0 mass%, Cr 0.15-0.25 mass%, Ti 0.005-0.20 mass%, or Ti 0.005-0.20 mass% and B 0.0005-0.05 mass% The balance is composed of Al and inevitable impurities, and Si in the impurities is 0.15% by mass or less, Fe is 0.4% by mass or less, Mn is 0.06% by mass or less, and Zn is 0.25% by mass. % or less, the Cu and 0.03 wt% or less, T _CR wt% and the content of said Cr, when the solid solution amount of Cr was S _CR wt%, the value P _CR of T _CR -S _CR is, P _An aluminum alloy plate with _CR ≦ 0.065 mass% is coated with 3 to 12 μm of sulfuric acid anodized film, and the film color tone is L * value 75 to 95, a * value −0.8 to 0, b * value 0 An aluminum alloy plate provided with an anodized film characterized by being -2.0.

( 2 ) The ingot having the composition described in the above (1) is hot-rolled after homogenization treatment, and in all annealing treatments after the subsequent cold-rolling, the temperature increase and temperature decrease rates are set to 100 ° C./second or more. A method for producing an aluminum alloy plate provided with an anodized film, wherein the aluminum alloy plate obtained by the method is coated with a 3 to 12 μm sulfuric acid anodized film .

  That is, the present invention includes (1) an aluminum alloy plate suitable for sulfuric acid anodizing treatment, (2) an aluminum alloy plate provided with sulfuric acid anodizing film, and (3) a method for producing an aluminum alloy plate suitable for sulfuric acid anodizing treatment. (4) A method for producing an aluminum alloy plate provided with a sulfuric acid anodized film is provided.

  The Al—Mg-based alloy plate containing Cr of the present invention is a light green in which the amount of Cr-containing intermetallic compound is set to a predetermined value or less to suppress yellowness as much as possible even when an anodized film is coated with a sulfuric acid bath. Because it is a white color aluminum alloy plate, the color selection range is widened, and it is used for enclosures such as interior / exterior panels and equipment for construction, home appliances, digital cameras and PCs, etc. It has an effect that can be done. Moreover, the manufacturing method of this alloy plate has the effect that the plate which has the said effect can be provided easily by the technical application of the grade which makes the temperature increase / decrease rate at the time of plate making rapid.

  The reason for limiting the chemical composition in the present invention will be described.

<Mg: 2.0 to 3.0% by mass>
Mg is a main element of JISA5xxx series alloy, and is an element for imparting sufficient strength only by work hardening. If it is less than the lower limit, it becomes insufficient in strength when processed into a panel or a container, and if it exceeds the upper limit, it lacks formability. .

  In an Al—Mg alloy containing only Mg, the surface color tone is colored light gray by sulfuric acid electrolytic bath system anodizing treatment.

<Cr: 0.15 to 0.25% by mass>
Cr is an element for refining recrystallized grains during intermediate annealing of JISA5xxx series alloys, and its effect is insufficient if it is less than the lower limit, and if it exceeds the upper limit, it is anodized even in the production method of the present invention. Strongly yellowish and unsuitable.

<Ti: 0.005-0.20 mass%> or <Ti: 0.005-0.20 mass% and B: 0.0005-0.05 mass%>
Ti or Ti and B are elements for refining the cast structure and effectively preventing cracking of the ingot during casting. Ti alone may be added, but when Ti and B are added in combination, the refinement performance of the cast structure is improved. This improves the ingot cracking prevention performance during casting. When the content is less than the lower limit, the effect of preventing cracking of the ingot is reduced with a small refining effect. If the upper limit is exceeded, a coarse intermetallic compound of Al-Ti or Ti-B will crystallize, impairing the workability and formability of the plate. The content of Ti or Ti and B can be adjusted by selecting a return material and appropriately selecting and adding one or more of Ti metal, Al—Ti master alloy or Al—Ti—B.

<Unavoidable impurities>
The unavoidable impurities, refers to intentionally added alloying elements Mg, Cr, Ti (or Mg, Cr, Ti and B) other elements, bullion in conventional melting method, the return member, master alloys and tools This is an unavoidable thing that gets mixed in. However, in the present invention, becomes many mixed amount of unavoidable impurities, it is necessary to limit so impair the distinctive color aqua white with suppressed yellowish of the element to develop the specific color present invention. That is, Si having a large influence is 0.15% by mass or less, Fe is 0.4% by mass or less, and Mn is 0.06% by mass or less. Others unavoidable impurities Zn 0.25 mass% or less, Cu 0. 1% by mass or less, preferably 0.05% by mass or less. The other elements are preferably regulated to 0.05% by mass or less.

_{<T CR -S CR = P CR} ≦ 0.065 wt%>
_{Here, T CR} content of Cr _{(wt%), S CR} is solid solution amount of Cr _{(mass%), P CR} is the amount of Cr in the intermetallic compound _{(mass%), P} CR = T represented by _CR -S _CR.

Yellowish is a Cr-containing intermetallic compound, for example, a compound represented by Al ₇ Cr, Al ₁₁ Cr, Al ₁₈ Cr ₂ Mg _3, etc., and incident light is reflected by these compounds, and the yellow wavelength is given priority. It is considered to have a strong taste.

<< Analysis of solid solution Cr >>
The Al content is dissolved with hot phenol, and Cr in the solution is analyzed by IPC emission spectrometry to determine the solid solution Cr (S _CR ). Since the value of _{S CR} is obtained by this method, Cr content _{(T CR)} from the _{T CR -S} CR _{= P} CR value, i.e. Cr content in the intermetallic compound _{(P CR} wt%) values can be calculated for .

《Yellow color suppression mechanism》
The value of this P _CR is a quantity of Cr present as compounds, that the value of P _CR is large, it means that the amount of Cr-containing compound is large, therefore, the inner prioritized the yellow wavelength of the incident light It is considered that the amount of light presenting is large and the yellowish color is strongly exhibited. If the P _CR value is less 0.065 mass%, the amount of Cr-containing compounds are also reduced, thus, can be considered as capable of suppressing light amount is small yellowish to yellow color wavelength.

Next, the preferable manufacturing method of the aluminum alloy plate of this invention is demonstrated.
A preferred production method of the invention includes the following steps.
<1> The ingot is hot-rolled after homogenization treatment, and then subjected to final annealing treatment after subsequent cold rolling.
<2> The ingot is subjected to hot rolling after homogenization, followed by intermediate annealing after subsequent cold rolling, followed by cold rolling and final annealing. Intermediate annealing can be performed multiple times.
<3> The ingot is subjected to hot rolling after homogenization treatment, followed by intermediate annealing treatment after subsequent cold rolling, and then cold rolling. Intermediate annealing can be performed multiple times.
<4> The ingot is subjected to hot rolling after homogenization treatment, intermediate annealing treatment after subsequent cold rolling, then cold rolling, and stabilization annealing treatment. Intermediate annealing can be performed multiple times.
<5> The ingot is subjected to hot rolling after homogenization treatment, and temper annealing treatment is performed after subsequent cold rolling.
<6> The ingot is subjected to hot rolling after homogenization treatment, intermediate annealing treatment after subsequent cold rolling, then cold rolling, and temper annealing treatment after cold rolling. Intermediate annealing can be performed multiple times.

In the aluminum alloy plate according to the present invention, the color tone of the anodized film is L ^* value is 75 to 95, a ^* value is −0.8 to 0, b ^* value is 0 to 2.0 under the composition of the present invention. However, in order to deepen the understanding of the technical relationship, an example of the most preferable production method is as follows.

The process <1> will be further described.
The molten alloy having the composition of the present invention is cast by a second half continuous casting method (DC casting), preferably through a filter, to obtain an ingot for rolling. The surface of the ingot is preferably chamfered to about 5 to 20 mm to remove a non-uniform layer on the surface of the ingot, and heated to 440 to 560 ° C. for about 1 to 24 hours or more to perform a homogenization heat treatment. To do. In the case of a multistage homogenization process, at least the high temperature stage should satisfy the temperature condition. This treatment reduces or eliminates the segregation of β phase (Mg ₂ Al ₃ ) and other local micro segregation such as Cr.

  Next, it is rolled to a thickness of about 2 to 10 mm by hot rolling. In the course of this hot rolling, the alloy elements are precipitated as fine intermetallic compounds, the recrystallized grains are refined by the final annealing treatment, and the hue is made uniform by the subsequent anodic oxidation treatment.

The step <2> will be further described.
The rolled sheet that has been hot-rolled in the same manner as in the step <1> is cold-rolled by a conventional method, subjected to intermediate annealing, softened to obtain an O material, and then cold-rolled by setting a rolling rate. A plate having a required thickness is formed, and then final annealing is performed. The intermediate annealing treatment may be performed a plurality of times.

The step <3> will be further described.
The rolled sheet that has been hot-rolled in the same manner as in step <1> is cold-rolled by a conventional method, subjected to intermediate annealing, softened to obtain an O material, and then cold-rolled with a rolling rate determined. To give the required mechanical properties. The intermediate annealing treatment may be performed a plurality of times.

The process <4> will be further described.
Since the Al—Mg alloy is naturally softened after cold working and the strength is not stabilized, when a stable material is required, a stabilization treatment is performed after the final cold rolling. That is, the rolled sheet that has been hot-rolled in the same manner as in step <1> is subjected to cold rolling according to a conventional method, subjected to intermediate annealing, softened to obtain an O material, and then finally cold-rolled and stabilized. Annealing is performed. The intermediate annealing treatment may be performed a plurality of times.
The process <5> will be further described.
If the composition and the cold rolling rate of Al-Mg alloy are known, the mechanical properties can be predicted by determining the heating conditions after cold rolling, so hot rolling is performed in the same manner as in step <1>. The finished plate is rolled by cold rolling according to a conventional method by setting a cold rolling rate, and is subjected to temper annealing after the rolling.
The process <6> will be further described.
If the composition and the cold rolling rate of Al-Mg alloy are known, the mechanical properties can be predicted by determining the heating conditions after cold rolling, so hot rolling is performed in the same manner as in step <1>. The finished plate is cold-rolled by a conventional method, subjected to intermediate annealing, softened to obtain an O material, and then rolled at a cold rolling rate, and subjected to temper annealing after the rolling. The intermediate annealing treatment may be performed a plurality of times.

This intermediate annealing, final annealing, stabilization annealing, and temper annealing temperature increase and temperature decrease rate conditions are important for obtaining the color tone of the present invention. That is, it is to suppress the precipitation of intermetallic compounds containing Cr as much as possible. The intermediate annealing or final annealing conditions are maintained at a temperature of 370 to 500 ° C. for 1 to 100 seconds to obtain an O material. When performing the stabilization annealing treatment after the intermediate annealing, it varies depending on the degree of the applied strength, and after the cold rolling, the stabilization annealing is performed by maintaining the temperature at 150 to 250 ° C. for 1 to 100 seconds.
When the cold rolling is determined and cold rolling is performed, and the temper annealing treatment is performed after the rolling, the conditions vary depending on the finally required mechanical properties, and after cold rolling, the temperature is set to 1 to 250 to 370 ° C. The temper annealing process is performed for 100 seconds.

  Here, the production method of the present invention is characterized by the following (A) that is necessarily applied or (B) or (C) that is applied as necessary.

<Rapid temperature increase / decrease during intermediate annealing, final annealing, stabilization annealing and temper annealing>
(A) Precipitation of an intermetallic compound containing Cr generated in the temperature raising and temperature lowering process at a temperature rising rate of 100 ° C./second or more at a temperature rising rate of 100 ° C./second or more in the intermediate annealing, final annealing or both annealing temperature ranges. Control and coarsening.

(B) The temperature rise to the stabilized annealing temperature range and the temperature drop rate up to 100 ° C. performed as necessary are set to 100 ° C./second or more, and are generated in the temperature rise and temperature drop process similar to (A) above. Suppression of precipitation and coarsening of intermetallic compounds containing Cr are prevented.
(C) As in (A) above, between the metals containing Cr generated in the temperature raising and temperature lowering process, with the temperature rising to the temper annealing treatment temperature range and the temperature lowering rate to 100 ° C. being 100 ° C./second or more. Prevents the precipitation and coarsening of the compound.
These annealing treatments are possible, for example, by raising the temperature using an electromagnetic induction heating furnace and lowering the temperature by water cooling.

  An aluminum alloy sheet obtained by annealing by rapid heating / rapid cooling that satisfies both the above conditions (A) or (B) or (C), which is applied as necessary, is obtained by subjecting Cr to an It is possible to suppress the yellowish color development due to the intermetallic compound containing, and to develop a light green white color without yellowishness.

  In addition, you may perform a hot rolling and a cold rolling as a separate process as mentioned above, and you may carry out as a consistent process continuously from a hot rolling temperature range to a cold rolling temperature range. In the case of the latter hot / cold integrated process, all the matters related to the cold rolling are applied in the cold rolling temperature range.

<Conditions for anodizing treatment>
The aluminum alloy plate according to the present invention is subjected to anodizing treatment with a sulfuric acid bath. The conditions are not limited, but the most preferable conditions are as follows. That is, since rolling oil is used in the rolling process during plate making, it is usually immersed in an acidic aqueous solution containing about 3 to 20% by mass of nitric acid in order to remove the oil adhering to the plate surface. The rolled sheet from which the oil content has been removed is an alkaline solution containing about 5 to 30% by weight of caustic soda after washing in order to remove oxides on the surface and form an anodized film uniformly by anodizing with a sulfuric acid bath after dripping. It is immersed in an aqueous solution and etched to remove several μm of surface layer. The rolled sheet etched by this alkali treatment is washed with water and then in a sulfuric acid bath containing 10 to 30% by mass of sulfuric acid, with the rolled sheet as the anode, the anode current density is 0.5 to 5 A / dm ² , preferably 1 to 3 A. / Dm ² , an electrolytic bath temperature of 5 to 30 ° C., preferably 10 to 30 ° C., and an electrolysis time of 10 to 120 minutes is applied to form a film thickness of 3 to 12 μm. In this film thickness range, according to the display method by UCS, the film color tone is L ^* value 75 to 95, a ^* value -0.8 to 0, b ^* suppression of bright yellowish value 0 to 2.0 A natural coloring film colored light green and white is obtained.

<Thickness of anodized film: 3 to 12 μm>
When the thickness of the anodized film is less than 3 μm, the corrosion resistance and scratch resistance are insufficient, and conversely, when it exceeds 12 μm, the yellowish color becomes strong and a preferable pale green and white cannot be obtained. Therefore, the thickness of the anodized film is limited to the range of 3 to 12 μm.

<Color tone after anodizing>
The display method of the color tone after the anodizing treatment is based on UCS, and this UCS is defined by JISZ8729 and JISZ8730. That is, JISZ8729 is described in the object color display method using the L ^* a ^* b ^* color system and the Luv color system, and JISZ8730 is described in the color difference display method.

The L ^* value shown in JISZ8730 indicates lightness, and the higher the value, the brighter the tone. The a ^* value and b ^* value indicate the hue, and when reddish, the a ^* value increases. On the other hand, if it becomes yellowish, b ^* value will become high, and it will become blueish, so that it becomes smaller than 0. The color tone obtained by the sulfuric acid bath of the aluminum alloy plate of the present invention has an L ^* value of 75 to 95, an a ^* value of −0.8 to 0, and a b ^* value of 0 to 2.0. It is light green and white as much as possible.

It demonstrates further using the board manufactured at the process of said <2>.
The molten alloy having the composition shown in Table 1 was melted and then passed through a filter to obtain a rolling ingot having a thickness of 560 mm by a DC casting method. The surface of the ingot was chamfered by 10 mm, held at a temperature of 440 ° C. for 2 hours, further heated and held at a temperature of 540 ° C. for 4 hours for homogenization.
Next, hot rolling of each ingot was started at a temperature of 530 ° C. and rolled to a thickness of 8 mm. The temperature of the hot rolled sheet at the end of hot rolling was 360 ° C.
The 8 mm rolled plate was cold rolled to 3 mm. This 3 mm plate was subjected to intermediate annealing by raising the temperature and changing the temperature-decreasing rate to 100 ° C. and maintaining the temperature at 425 ° C. for 10 seconds to obtain an O material.
Next, it cold-rolled to thickness 1mm (rolling rate 67%). This 1 mm plate was subjected to final annealing by maintaining the temperature at 425 ° C. for 10 seconds while increasing the temperature and changing the temperature decrease rate to 100 ° C.
Next, flatness was obtained through a tension leveler and cut into 100 mm × 100 mm to prepare a sample for the next anodic oxide film treatment.

  The anodized film treatment process is as follows.

The surface of each sample is washed with an organic solvent and degreased, immersed in an 8% aqueous solution of caustic soda for 2 minutes at a liquid temperature of 50 ° C., caustically treated, and after washing with water, immersed in an aqueous nitric acid solution at 20 ° C. for 10 minutes. Neutralized. Each sample pretreated in this way was then subjected to a bath temperature of 18 ° C., a 15 mass% sulfuric acid bath, a current density of 1 A / dm ² , and a treatment time to produce oxide films of various thicknesses. After washing with water, it was sealed with warm water at 95 ° C. and dried. The color tone was then measured with a MINOLTA CM508i instrument. The results are shown in Table 2.

From the results shown in Table 2, the present invention example (sample number) in which both the temperature rise and temperature drop rates of the intermediate annealing and the final annealing treatment are equal to or higher than the specified speed even if Cr is contained within the specified range in the Al—Mg alloy. Examples of the present invention (2-1, 2-2, 2-3) show that the color tone of the anodic oxide film is light green-white with yellowness suppressed. On the other hand, in the comparative example (sample number 2-4) in which the Cr amount is greatly out of the specified range, even if the temperature rising and cooling rates are both higher than the specified speed, the _PCR value is high and the yellowish gray is strong. I know that.
Moreover, it turns out that the green color and the yellowish color develop strongly in the comparative example (film thickness 15 μm of sample numbers 2-1, 2-2, 2-3) in which the film thickness exceeds 15 μm. .
Moreover, even the chemical composition is a present invention embodiment, if any of the heating and cooling rate is slower than the specified range (Sample No. 2-5 and 2-6), the strong high yellowish be P _CR value gray It turns out that it is.

It demonstrates further using the board manufactured at the process of said <4>.
After melting the molten alloy having the composition shown in Table 1, a DC casting method was performed through a filter to obtain a rolling ingot having a thickness of 560 mm. The surface of the ingot was chamfered by 10 mm, held at a temperature of 440 ° C. for 2 hours, further heated and held at a temperature of 540 ° C. for 4 hours for homogenization.

  Next, hot rolling of each ingot was started at a temperature of 530 ° C. and rolled to a thickness of 6 mm. The temperature of the hot rolled sheet at the end of hot rolling was 360 ° C.

  The 6 mm rolled plate was cold rolled to 1.5 mm. The 1.5 mm plate was subjected to intermediate annealing by changing the temperature rising rate and the temperature decreasing rate up to 100 ° C. for 10 seconds, and was subjected to intermediate annealing to obtain an O material.

  Next, it cold-rolled to thickness 1mm (rolling rate 33%). This 1 mm plate was stabilized and annealed by maintaining the temperature at 220 ° C. for 10 seconds while increasing the temperature and changing the temperature decrease rate to 100 ° C.

  Next, the flatness was obtained through a tension leveler, cut into 100 mm × 100 mm, and anodized film treatment was performed in the same manner as in Example 1. Thereafter, the color tone was measured in the same manner as in Example 1. The results are shown in Table 3.

  From the results of Table 3, the present invention example (sample) in which both the temperature rise and temperature drop rates of the intermediate annealing and the stabilized annealing treatment are equal to or higher than the specified rate even if Cr is contained within the specified range in the Al—Mg alloy It can be seen that the examples of the present invention (numbers 3-1, 3-2, and 3-3) are light green white in which the color tone of the anodized film is suppressed to yellow.

On the other hand, in the comparative example (sample number 3-4) in which the Cr amount is significantly out of the specified range, even if the temperature rising and cooling rates are both higher than the specified speed, the _PCR value is high and the yellowish gray is strong. I know that.

  Further, in the comparative example (the film thickness of 15 μm of sample numbers 3-1, 3-2, and 3-3) in which the film thickness exceeds 15 μm, the green color and the yellow color may be strongly colored. I understand.

Moreover, even the chemical composition is a present invention embodiment, if any of the heating and cooling rate is slower than the specified range (Sample No. 3-5, 3-6) are strong high yellowish be P _CR value gray It turns out that it is.
In addition, the composition within the specified range manufactured in the steps described in <1>, <3>, <5> and <6> other than <2> and <4> demonstrated in Examples 1 and 2 For aluminum alloy sheets, the temperature after heating and cooling is 100 ° C./second or more in all annealing processes after cold rolling, so that the color tone after anodization within the specified range is within the specified L ^* value, The a ^* value and b ^* value were obtained, and it was confirmed that a pale green white with no yellowishness was obtained visually.

  In the plate 1 mm after the cold rolling of sample number 3-2 made under the conditions of Example 2, the plate on the first day after the cold rolling and the plate on the 10th day without the stabilization annealing after the cold rolling The mechanical properties of the plate on the first day after the stabilization annealing and the plate on the tenth day after the stabilization annealing were measured. The results are shown in Table 4.

  From the results of Table 4, the mechanical properties of the plate subjected to stabilization annealing (Sample No. 4-2) are stable even after 10 days, whereas the plate not subjected to stabilization annealing (Sample No. 4). It can be seen that the mechanical properties of -1) fluctuate greatly after 10 days.

  ADVANTAGE OF THE INVENTION According to this invention, even if it anodizes with a sulfuric acid bath, the aluminum alloy plate which can suppress yellowish color development as much as possible, and develops the light green-white color which does not have a reddish taste, and its manufacturing method are provided.

Claims (4)

Mg 2.0-3.0% by mass, Cr 0.15-0.25% by mass, Ti 0.005-0.20% by mass and B0.0005-0.05% by mass, from the remaining Al and inevitable impurities In the impurity, Si is 0.15% by mass or less, Fe is 0.4% by mass or less, Mn is 0.06% by mass or less, Zn is 0.25% by mass or less, and Cu is 0.03 % by mass or less. and then, T _CR wt% and the content of said Cr, when the solid solution amount of Cr was S _CR wt%, the value P _CR of T _CR -S _CR is, the aluminum alloy is a P _CR ≦ 0.065 wt% The plate is coated with a sulfuric acid anodized film of 3 to 12 μm, and the film color tone is L * value 75 to 95, a * value −0.8 to 0, b * value 0 to 2.0. Aluminum alloy plate with an anodized film. A method for producing an aluminum alloy plate comprising the anodized film according to claim 1,
Mg 2.0-3.0% by mass, Cr 0.15-0.25% by mass, Ti 0.005-0.20% by mass and B0.0005-0.05% by mass, from the remaining Al and inevitable impurities In the impurity, Si is 0.15% by mass or less, Fe is 0.4% by mass or less, Mn is 0.06% by mass or less, Zn is 0.25% by mass or less, and Cu is 0.03 % by mass or less. An aluminum alloy obtained by a method in which an ingot having the composition as described above is hot-rolled after homogenization treatment and the temperature rise and fall rates are 100 ° C./second or more in all annealing treatments after the cold rolling. A method for producing an aluminum alloy plate provided with an anodized film, wherein the plate is coated with 3 to 12 μm of a sulfuric acid anodized film. It contains Mg 2.0-3.0 mass%, Cr 0.15-0.25 mass%, Ti 0.005-0.20 mass%, and consists of the balance Al and unavoidable impurities. 15% by mass or less, Fe 0.4% by mass or less, Mn 0.06% by mass or less, Zn 0.25% by mass or less, Cu 0.03 % by mass or less, and the content of Cr is T _CR wt%, when the solid solution amount of Cr was S _CR wt%, the value P _CR of T _CR -S _CR is, P _CR ≦ 0.065 sulfate anodized film on the aluminum alloy plate is mass% 3~12μm An aluminum alloy plate provided with an anodized film, which is coated and has a color tone of L * value of 75 to 95, a * value of −0.8 to 0, and b * value of 0 to 2.0. A method for producing an aluminum alloy plate comprising the anodized film according to claim 3,
It contains Mg 2.0-3.0 mass%, Cr 0.15-0.25 mass%, Ti 0.005-0.20 mass%, and consists of the balance Al and unavoidable impurities. Homogenizing an ingot comprising 15% by mass or less, Fe 0.4% by mass or less, Mn 0.06% by mass or less, Zn 0.25% by mass or less, and Cu 0.03 % by mass or less . Hot-rolling after the treatment, and in all the annealing treatments after the cold-rolling, the sulfuric acid anodic oxide film is applied to the aluminum alloy plate obtained by the method of raising the temperature and the temperature-decreasing rate to 100 ° C./second or more. A method for producing an aluminum alloy plate provided with an anodized film, characterized by comprising coating.