JP2711970B2 - High-strength aluminum alloy wrought material having a matte dark gray to black color after anodizing and a method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires anodized aluminum alloy to be used after being subjected to an anodizing treatment, particularly, it is required to have a matte dark gray to black color tone and a high strength. Aluminum alloy wrought material for various uses and a method of manufacturing the same, for example, parts of a semiconductor device manufacturing apparatus such as a pellicle frame and an IC pattern printing frame,
Alternatively, the present invention relates to an aluminum alloy wrought material used for parts of an optical device or an optical communication device, or a housing of an electric measuring instrument, and a method for producing the same.

[0002]

2. Description of the Related Art In many cases, aluminum alloy parts such as parts of semiconductor manufacturing equipment and optical equipment or optical communication equipment are required to be black and non-reflective to light.
Further, in order to form a precision component by machining, it is often required that the component has high strength, specifically, has a proof stress of at least 250 N / mm ² or more. As a typical example, there is a pellicle frame which is a carrier when a circuit of an IC substrate is printed.

Conventionally, as the pellicle frame as described above, JIS 7075 which is an Al—Zn—Mg based alloy is used.
After processing a rolled plate or extruded T6 material made of an alloy, the surface is mechanically or chemically roughened to make it dull and then dyed black with a dye. there were.

[0004]

In the circuit baking of an IC substrate, recently, with the increase in the density of IC circuits, it is necessary to use an ultraviolet ray such as an excimer laser having a higher resolution than visible light for baking. More. However, in this case, when the pellicle frame which is blackened by the above-described dyeing is used, there is a problem that the color tone of the pellicle frame is decolored at an early stage due to ultraviolet rays, and the pellicle frame cannot be used.

Therefore, as a material of the pellicle frame,
There is a strong demand for the development of a non-reflective, black aluminum alloy material that does not easily decolor by ultraviolet light and has high mechanical strength. Further, in this case, development of an aluminum alloy material which exhibits a black color while maintaining anodizing treatment with an inexpensive sulfuric acid bath is desired mainly from an economic viewpoint.

In addition to the pellicle frame,
In the field of handling various lights, parts that are required to be black and matte and have precise dimensional accuracy in order to prevent light halation are often required. Although there is a demand for a material that does not discolor black due to aging even in a high energy state, there are few conventional aluminum alloy materials that satisfy these requirements simultaneously and sufficiently.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and exhibits an aluminum alloy exhibiting a dark gray to black matte color tone as anodized and having a high strength of 250 N / mm ² or more. It is intended to provide a drawn material.

[0008]

The inventors of the present invention have conducted various experiments and studies to solve the above-mentioned problems. As a result, the type, size, and distribution density of the Mn-based precipitates in the aluminum alloy were found to be anodized. relates to matt black coloring, in particular Al ₆
Found that be deposited at a high density as a predetermined size of the Mn-based intermetallic compound precipitates is important to matt black coloring of the anodized film, and because the matte black coloring of the anodized film find appropriate alloy component composition, and further have found optimum process conditions to achieve matt black coloring and strengthening of the anodic oxide film, leading to the completion of this invention.

[0009]

More specifically, the wrought aluminum alloy according to the first aspect of the present invention has a Mn content of 1.0 to 2.5% and a Mg content of 2.1%.
6-4.0%, contains more than 5.5% and 9.5% or less of Zn, and further contains less than 0.3% of Cu, less than 0.2% of Si, and less than 0.3% of Fe as impurities. is restricted, the balance being from unavoidable impurities other than Al and above, yet as a fold-out of Al 6 _Mn system of intermetallic compound precipitate of a size in the range of 0.01μm~3μm 1
× 10 ⁴ / mm ² is a wrought material having a proof strength of 250 N / mm ² or more and a matte dark gray to black color after anodizing, characterized by being dispersed at a density of ⁴ or more / mm ² or more. is there.

[0011] Further, the invention according to claims 2 to 7 has the above-mentioned component composition and has an Al ₆ Mn-based precipitate of 0.01 μm as an intermetallic compound precipitate.
1 × 10 ⁴ pieces / mm in size within the range of 〜3 μm
Dispersed at a density of ² or more, with a proof strength of 250 N / mm ²
The above method relates to a method for producing an aluminum alloy wrought material having a matte dark gray to black color after anodizing treatment.
0 to 2.5%, Mg 2.16 to 4.0%, Zn 5.5%
And 9.5% or less, and C as an impurity
u is less than 0.3%, Si is less than 0.2%, Fe is 0.3%
%, And the balance is cast from an aluminum alloy consisting of Al and inevitable impurities other than those described above, and further subjected to wrench processing to form a wrought material at 400 to 550 ° C. at any stage after casting. 0.5 to a temperature in the range of
After the precipitation process, the material after the drawing process is heated to a temperature within the range of 400 to 550 ° C. after or together with the precipitation process.
It is characterized by performing solution treatment-quenching at a cooling rate of 0 ° C./min or more.

The method according to the third aspect of the present invention is the method according to the second aspect.
In the method described in the above, hot working is performed as the spreading process, the precipitation process is performed as ingot heating prior to the hot working process, and the solution treatment-quenching is performed at 20 ° C. immediately after the hot working process. The cooling is performed at a cooling rate of not less than / min or at a cooling rate of not less than 20 ° C / min by heating to 400 to 550 ° C again after hot working.

[0013] A fourth aspect of the present invention is the method according to the third aspect, wherein hot rolling is performed as the hot working.

According to a fifth aspect of the present invention, in the method according to the third aspect, hot extrusion is performed as the hot working.

[0015] The method according to claim 6 is the method according to claim 2.
In the method described in the above, as the spreading, hot rolling and cold rolling are performed, and the precipitation treatment is performed as ingot heating prior to hot rolling, and the solution treatment-quenching, The process is performed on a cold-rolled sheet after rolling.

Further, the method according to the invention of claim 7 is the method according to any one of claims 2 to 6, wherein after the solution treatment-quenching, the temperature is from 80 to 200 ° C.
And a high-temperature aging treatment of heating for 1 to 48 hours at a temperature within the range described above.

[0017]

The present inventors have determined that the type, size, and distribution density of Mn-based precipitates, particularly Al ₆ Mn-based precipitates, in an aluminum alloy have a dull color tone after anodizing as described above.
It was found that a significant impact on the black coloring.

That is, as the Mn-based precipitates in the aluminum alloy, there are generally those shown in the following a to g. _{a: Al 6 Mn b: Al} 6 Mn in Al ₆ part forms replacing a Fe of Al (MnFe) c: part of Al ₆ Mn of Al forms replacing a Si (AlSi) ₆ Mn d : (AlS Mn) of the type in which part of Al of Al ₆ Mn is replaced by Si and part of Mn is replaced by Fe
i) ₆ (MnFe) e: A substance in which a small amount of Cu, Cr, Ti or the like is dissolved in any of a to d f: αAlMn (Fe) Sig: A substance in which a small amount of Cu, Cr, Ti, or the like is dissolved in f: α

Of these Mn-based precipitates a to g, a
To e can be collectively referred to as Al ₆ Mn-based precipitates. And among such Al ₆ Mn-based precipitates, 0.1.
It is necessary to matt black coloring of color tone after the anodic oxidation treatment intended 3μm or less in size than 01μm are dispersed in 1 × 10 ⁴ pieces / mm ² or more in the distribution density. That is, the Al ₆ Mn-based precipitate is not oxidized during the anodic oxidation treatment in a sulfuric acid bath or the like, and remains as it is as metal compound particles in the anodic oxide film. is scattered by between compound particles will exhibit dark gray-black matte as a whole film. On the other hand, the α-AlMn (Fe) Si of f and the precipitate of g in which Cu, Cr, Ti and the like are dissolved in solid solution are oxidized during the anodic oxidation treatment in the sulfuric acid bath, and the color tone of the anodic oxide film becomes yellow. Has no effect on blackening. Therefore, the present invention specifies an Al ₆ Mn-based precipitate.

[0020] Here, depending on the _Al 6 Mn based precipitate-free
To present a charging amount of black gloss, it is important that precipitates size within a predetermined range are dispersed at a high density. The size of the Al ₆ Mn-based precipitate is 0.0
If it is less than 1 μm, the particles are too small to contribute to the blackening of the anodic oxide film, and the pink-yellow tint becomes strong. On the other hand, Al ₆ M
In the case of n-type precipitates that are only coarser than 3 μm,
Actually, the distribution density of the precipitates is reduced, and the color tone after the anodic oxidation treatment is reduced. The distribution density of Al ₆ Mn-based precipitates having a size in the range of 0.01 to 3 μm is 1 × 1.
0 is less than ⁴ / mm ^2, the distribution of Al 6 _Mn based precipitate of that size is too sparse, the anodized film is not sufficiently blackened. Incidentally, in this invention, a main size of the _Al 6 Mn in the range of 0.01~3μm contributes to matt black coloring
If the system precipitates are dispersed at a dispersion density of 1 × 10 ⁴ particles / mm ² or more, a matte dark gray to black can be exhibited, and if the conditions are satisfied, other than Al ₆ Mn system That precipitates of the type
The fact that the precipitates having a size outside the above range are not hindered.

However, even if it is an Al ₆ Mn-based precipitate,
If e or Si forms a solid solution to form the above-mentioned b to d, the precipitates are easily oxidized or dissolved at the time of anodic oxidation treatment in a sulfuric acid bath, so that it is difficult to obtain a sufficient black color. In particular, Al ₆ Mn
If the amounts of Fe and Si in the system precipitates are large, it is difficult to surely and stably obtain black. Therefore, in the present invention, not only the Mn content but also the Fe content and the Si content are regulated as the component composition of the entire alloy.
Also, if the amount of Cu in the alloy increases, Al-Mn-based precipitates
It changes to a u ₂ Mn ₃ Al ₂₀ based precipitate and blackening is not sufficient, so the Cu content of the alloy is also regulated.

Hereinafter, the reasons for limiting the alloy components in the present invention will be described. Each alloying elements below, at the same time controlling the precipitation state of precipitates so as to enable a matte black coloring after anodizing treatment as described above, natural aging (natural aging) or artificial aging (artificial aging) Strength is 25
It is determined so that a high strength of 0 N / mm ² or more can be obtained.

[0023] Mn: Mn is an element for generating Al-Mn-based intermetallic compounds, for matt black coloring a particular color tone after the anodic oxidation treatment to precipitate Al 6 _Mn based precipitate in this invention Is an important element. That is, as described above, according to the present invention, by depositing Al ₆ Mn-based precipitates having a size within a predetermined range at a predetermined density, the anodizing treatment can be performed.
It is made in found that in it is possible to matt black coloring. If the Mn content is less than 1.0%, Al ₆ M
The deposition amount of the n-based precipitate is small, and sufficient blackening of the anodic oxide film is not achieved. On the other hand, if the Mn content exceeds 2.5%, blackening of the anodic oxide film is possible, but it is not preferable because coarse primary crystals of the intermetallic compound are formed during DC casting. Therefore, the Mn content is set in the range of 1.0 to 2.5%.

[0024] Mg: Mg is an element that promotes the precipitation of Mn, contributing _Al 6 Mn in matt black coloring when anodized film of the present invention
It is an element indispensable for precipitating a system precipitate at a predetermined size and density. In particular, when a casting method such as a DC casting method, in which the cooling rate at the time of casting is smaller than that of the continuous casting method of a thin plate (continuous casting rolling method), is applied, the amount of Mn forced solid solution at the time of casting is small. If the amount of Mg is not present, Al
₆ The size and density of Mn-based precipitates are matte and dark gray
The state is not suitable for obtaining a black anodic oxide film. Mg is an element that forms MgZn ₂ in coexistence with Zn. Therefore, in the case of the present invention, it contributes to strength improvement by aging after solution treatment and quenching. Mg content 2.16
%, Sufficient strength cannot be obtained, and sufficient blackening of the anodic oxide film cannot be achieved. On the other hand, if it exceeds 4.0%, blackening of the anodic oxide film is possible.
Hot rollability deteriorates. Therefore, the Mg content is 2.16 to
It was within the range of 4.0%.

Zn: As described above, Zn coexists with Mg and contributes to strength improvement. Zn has the effect of accelerating the precipitation of Mn.
No effect on the type of precipitate of n
This contributes to an improvement in strength without adversely affecting the tone of the achromatic black. If Zn is less than 5.5%, the effect of increasing the strength by adding Zn cannot be sufficiently obtained, while if Zn exceeds 9.5%, casting becomes difficult, and
Hot deformation resistance also increases, making hot rolling difficult. Therefore, the Zn content is set in the range of more than 5.5% and 9.5% or less.

Cu: Cu is an element effective for increasing the strength in coexistence with Zn and Mg, and is generally an element that is often added as a strength improving element in a No. 7000 series alloy. , The content of Cu is defined as a harmful element. That is, if the amount of Cu increases, Al
-Mn based precipitates ends up changing the Cu ₂ Mn ₃ Al ₂₀ based precipitate prevents blackening of the anodized film is less Al ₆ Mn based precipitate. In particular, if Cu is 0.3% or more, sufficient blackening of the anodic oxide film cannot be achieved, so it is necessary to limit Cu to less than 0.3%.

Fe: Fe coexists in Al ₆ Mn as Al ₆ (MnFe) so as to partially replace Mn. This Al ₆ (MnFe) gradually becomes more susceptible to oxidation at the time of the anodic oxidation treatment as the amount of Fe increases, and the anodic oxide film hardly turns black. F in all Al ₆ Mn-based precipitates
If the amount of e is less than 20%, the black color of the anodic oxide film is maintained, but if it exceeds 20%, the blackening of the anodic oxide film becomes insufficient. Therefore, it is desirable that the amount of Fe in the alloy is as small as possible. If the amount of Fe is 0.3% or more, the blackening of the anodic oxide film becomes insufficient, so that Fe is limited to less than 0.3%. It shall be.

[0028] Si: Si is Al in ₆ Mn, in the form that replaces a portion Al as (AlSi) ₆ Mn. This (AlSi) ₆ Mn is also easily oxidized during the anodic oxidation treatment as the amount of Si increases, and the anodic oxide film is hardly blackened. Si is αAlMn (Fe) Si
However, this αAlMn (Fe) Si does not contribute to the blackening of the anodic oxide film. Therefore, it is desirable that the amount of Si is as small as possible. If the amount of Si is 0.2% or more, the yellow tint becomes strong and blackening of the anodic oxide film cannot be achieved, so the amount of Si is limited to less than 0.2%. It was decided to.

In addition to the above elements, basically, Al
And Cr, Zr, V, Ni, which are often contained in ordinary aluminum alloys.
Without causing substantial effect on the matt black coloring also anodized film eventually, where Cr, Zr, V up to 0.3% respectively, Ni may be contained up to 1%. Cr, Z
If r and V exceed 0.3%, and if Ni exceeds 1%, a coarse intermetallic compound is generated, which is not preferable. In general Al alloys, a small amount of Ti may be added alone or in combination with a small amount of B in order to refine the ingot crystal structure and prevent texture and streaks of the rolled sheet. Also in the wrought aluminum alloy of the invention, it is permissible to add 0.15% or less of Ti alone or in combination with 100 ppm or less of B. Ti is 0.
If it exceeds 15%, TiAl ₃ coarse intermetallic compounds are formed and become unsuitable, and if B exceeds 100 ppm, B
Is saturated, and linear defects due to coarse TiB ₂ particles are generated, which is unsuitable. Further, when Mg is added, the molten metal tends to be oxidized during casting, but in order to prevent the molten metal from being oxidized, Be is generally added. Does not adversely affect other performances, and therefore, a small amount of Be may be added. In this case, the amount of Be added is generally 500 ppm or less.

When the actions of the above elements are summarized, M
n, Mg, Zn are both an essential alloy components in the present invention, of which Mn contributes to matt black coloring of the anodized film, Mg, upon promotes matt black coloring of anodized film at the same time, contributes to improving the strength, further Zn contributes to improving the strength without impairing the matt black coloring of the anodized film. On the other hand, Cu, Fe, and Si are all harmful elements in the present invention, and all of them hinder the blackening of the anodic oxide film, so that their contents are regulated to small amounts.

Next, the production method of the present invention, that is, the production method of the wrought aluminum alloy according to claims 2 to 7 will be described.

[0032] This manufacturing method is basically, be carried out the precipitation process of heating to a temperature in the range of 400 to 550 ° C. at any stage after casting, the anodized film
Is required for the matte black coloring, also 400 to 550
In order to obtain high strength, it is essential to perform a solution treatment-quenching in which the material is heated to a temperature in the range of ° C and cooled at a cooling rate of 20 ° C / min or more. The solution treatment-quenching is generally performed at a later stage than the precipitation treatment. However, in some cases, the solution treatment-quenching heating (solution treatment) may be performed together with the precipitation treatment heating. it can.
These will be described more specifically.

First, an alloy having the above-mentioned composition is cast according to a conventional method. As a casting method, a DC casting method (semi-continuous casting method) is generally used, but a thin plate continuous casting method (continuous casting rolling method) may be applied. For ingots obtained by DC casting, ingot heating is generally performed for homogenization,
In addition, it is usual to perform preliminary heating for hot working together with or separately from heating of the ingot for this homogenization, and then to perform hot rolling or hot extrusion as hot working thereafter. . In the case of hot rolling, the hot-rolled sheet thickness is used as a product sheet, or cold rolling is performed after hot rolling to a predetermined sheet thickness. On the other hand, when the thin sheet continuous casting method is applied, it is usual that the cast sheet is subjected to a homogenizing treatment as necessary and then subjected to cold rolling to a predetermined sheet thickness. And in the case of the method of the present invention, at any of these stages after casting, Mn dissolved during casting
Need to be subjected to a heat treatment (precipitation treatment) for precipitating as an Al ₆ Mn-based intermetallic compound as described above. This precipitation treatment is generally performed at the stage of a cast ingot or a continuous cast plate, but may be performed at a stage after hot rolling or hot extrusion, or when performing cold rolling. It is also possible to carry out a precipitation treatment in the middle or at a later stage of the cold rolling.

This precipitation treatment may be carried out independently for the purpose of precipitation alone, but it is usually economically advantageous to carry out this treatment together with another heat treatment. That is, precipitation treatment can be performed as ingot heating or casting plate heating, also serving as preheating for homogenization or hot working after casting, and between hot working and cold working, or cold working. When performing intermediate annealing in the middle of cold working, a precipitation treatment can be performed also as the intermediate annealing, and when performing final annealing after cold working, a precipitation treatment is also performed as the final annealing. It is also possible.

Here, it is necessary to carry out the precipitation treatment at a temperature in the range of 400 to 550 ° C. for 0.5 to 24 hours. That is, when the temperature is lower than 400 ° C., Al ₆
The precipitation of Mn-based precipitates is small, and the anodic oxide film is not sufficiently blackened, resulting in a reddish color. 55
If the temperature exceeds 0 ° C., the Al ₆ Mn-based precipitate once deposited will be re-dissolved, resulting in an insufficient amount of precipitation and eutectic melting. If the time is less than 0.5 hour, Al ₆ Mn
Insufficient precipitation of system precipitates, on the other hand, beyond 24 hours, the precipitation saturates and is only economically wasted.

On the other hand, in the solution treatment-quenching step, Mg and Zn contributing to age hardening are dissolved at a high temperature and rapidly cooled to a supersaturated solid solution, whereby natural aging (room temperature aging) or artificial aging (high temperature aging) is performed. This is a step for obtaining high strength by aging. This solution treatment-
The quenching is usually performed only on the material after the wrought process. Therefore, when the product is to be manufactured with the thickness and the shape dimensions as it is after hot working such as hot rolling or hot extrusion, the hot working is performed. It may be carried out after working, and when cold rolling is carried out after hot rolling, it may be carried out after cold rolling. However, if the product is to be made with the thickness and shape dimensions as it is after hot working, it is cooled once after hot working and then heated to the solution treatment temperature.
Although quenching may be performed, the solution treatment may be directly performed by using the temperature of hot working (holding heat) without heating again, and then quenching may be performed (corresponding to a case where a so-called T5 treated material is used). Further, in the case where the above-described precipitation treatment is performed in a state after the stretching (that is, when the heat treatment that satisfies the conditions of the above-described precipitation is not performed before the completion of the stretching), Heat treatment (solution solution) for solution treatment-quenching can also be performed in combination with the precipitation treatment.

The conditions for solution treatment and quenching as described above are as follows: a heating temperature for solution treatment is 400 to 550 ° C.
The cooling rate for quenching needs to be 20 ° C./min or more. If the temperature is lower than 400 ° C., the solid solution of Mg or Zn is insufficient, and the strength does not sufficiently increase due to aging thereafter.
On the other hand, if it exceeds 550 ° C., only eutectic melting occurs,
In the case of an extruded material, coarse recrystallized grains may be generated on the surface, and a pattern may be formed on the surface after the anodizing treatment. If the cooling rate of quenching is less than 20 ° C./min, quenching is insufficient and sufficient strength cannot be obtained by aging thereafter. In the case of a rolled sheet material, the solution treatment-quenching may be performed by a batch method in which a cut plate is solution-treated in a batch-type solution heating furnace and rapidly cooled, or the coil is continuously rewound. Alternatively, a continuous solution quenching furnace or a continuous annealing furnace in which the steel sheet is passed through the furnace may be used. In the case of extruded materials, a batch-type solution heat furnace is generally used. The holding time at 400 to 550 ° C. for the solution treatment is not particularly limited, but is preferably 5 minutes or more when using a batch type solution treatment furnace, and when using a continuous furnace,
Generally, the holding time is 30 seconds or more.

After the solution subjected to solution treatment and quenching is performed on the material subjected to the above-described stretching process, in the case of a cut plate of a rolled plate, if necessary, straightening is performed by a single plate leveler, stretch, or the like. Normally, in the case of a rolled plate coil, it is also usual to correct distortion by stretching after leveling or cutting as necessary, and also in the case of extruded material by stretching etc. as necessary. Straightening may be performed. In the case of a rolled material coil, if it is desired to further improve strength, after solution treatment-quenching,
Further, it is permissible to perform cold rolling, but also in this case, distortion correction is often performed after the final cold rolling.

The rolled or extruded material obtained as described above can be obtained as a T4 treated material by natural aging (room temperature aging) as it is, but it is possible to obtain a considerably high strength. In this case, an artificial aging (high temperature aging) treatment is performed to obtain a T6 treated material or a T5 treated material (when extruded material also serves as hot working for solution treatment). The condition of the artificial aging may be heating at a temperature in the range of 80 to 200 ° C. for 1 to 48 hours. If the heating temperature of the artificial aging is less than 80 ° C., sufficient strength cannot be obtained, while 200
If the temperature exceeds ℃, the strength will be reduced by overaging. If the heating time is less than 1 hour, sufficient strength cannot be obtained, and if the heating time exceeds 48 hours, it is only economically useless. Here, the artificial aging process may be performed by multi-stage aging, such as two-stage aging or three-stage aging, as long as it is within the above-mentioned condition range.

As described above, after performing the precipitation treatment at 400 to 550 ° C. × 0.5 to 24 hours at any stage after casting, in order not to affect the color tone after the anodic oxidation treatment, It is desirable not to perform heating at a high temperature exceeding the upper limit of the above-mentioned precipitation processing temperature condition range, and particularly to avoid heating at a high temperature exceeding the temperature of the actually applied precipitation processing. For example, in general, the precipitation treatment is often performed together with the homogenization treatment for the ingot and the preheating before hot working, but the intermediate annealing or the solution treatment performed as necessary in a later step as needed. It is desirable to carry out at a temperature equal to or lower than the temperature of the precipitation treatment.

As described above, in the ingot heating step or the like, the precipitation treatment is performed at 400 to 550 ° C. × 0.5 to 24 hours, and the solution is further formed into a solution at a temperature in the range of 400 to 550 ° C. Rolled material or extruded material obtained by performing the solution treatment-quenching at the above cooling rate,
Since the precipitates of the Al ₆ Mn-based compound having an appropriate particle size are dispersed at an appropriate distribution density, a dark gray to black matte color can be obtained as the color after the anodizing treatment, and the natural color can be obtained. High strength with a proof stress of 250 N / mm ² or more can be obtained by aging or further artificial aging treatment.

Although the specific method for anodizing the rolled or extruded material as described above is not particularly limited, in the case of the present invention, a highly economical sulfuric acid electrolytic bath is used. Dark gray to black due to anodizing
It is preferable to use a sulfuric acid electrolytic bath because a matte color tone can be stably and reliably obtained. Typical examples are described below.

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 using a sulfuric acid bath of 25 vol% at a bath temperature of 10 to 30 ° C. and a current density of 1.5 A / dm ² or more and less than 2.5 A / dm ² .

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 the treatment, and it 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 becomes thin and gray is obtained. Can not be. 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 above-mentioned sulfuric acid bath, a dark gray to black matte color tone can be stably obtained. Here, the color tone after the anodizing treatment can be evaluated by the values of the lightness index L and the chromaticness indices a and b according to the Hunter's color difference equation (see JIS Z8730). That is, the higher the L value of the lightness index, the whiter the color index is, while the chromaticness index is about the degree of coloring, and the higher the a value, the stronger the redness,
The higher the b value, the stronger the yellow color. The achromatic gray tone intended in the present invention is an L value, a
Value and b value can be defined as a color tone that satisfies L <45, −2 <a <+2, −2 <b <+2.

[0046]

【Example】

[Example 1] Molten alloys Nos. 1 to 5 shown in Table 1 were smelted according to a conventional method, and a slab of 450 mm x 1200 mm x 4000 mm was cast by a semi-continuous casting method (DC casting method). After facing each of the obtained slabs, 480 ° C. × 8 hours or 350 ° C. as shown in production numbers 1 to 6 in Table 2.
The ingot was heated under the conditions of × 2 hours, and hot rolling was started at the temperature shown in Table 2 to obtain a hot-rolled sheet having a thickness of 4 mm.
Here, the condition of 480 ° C. × 8 hours of ingot heating satisfies the condition range of the precipitation treatment defined in the present invention,
Therefore, it also serves as a precipitation treatment. On the other hand, the condition of ingot heating at 350 ° C. for 2 hours does not satisfy the precipitation treatment conditions specified in the present invention. Next, solution treatment and quenching were performed in a batch type solution treatment furnace. As shown in Table 2, the conditions of the solution treatment were 480 ° C. × 10 minutes or 380 ° C. × 10 minutes, and the quenching was carried out at a cooling rate of about 100 ° C./sec by water cooling. Thereafter, leveling was performed, followed by cutting and flattening by stretching. Then, after leaving at room temperature for one week,
An artificial aging treatment for 20 hours was performed.

Thereafter, each plate was etched with a 10% aqueous solution of NaOH, washed with water, and then desmutted with nitric acid. Next, using a sulfuric acid bath having a H ₂ SO ₄ concentration of 15 vol%, anodizing treatment was performed at a bath temperature of 20 ° C. and a current density of 1.5 A / dm ² to form anodized films having a thickness of 25 μm each.

Regarding the surface tone of the anodic oxide film of each plate,
It was examined using a color meter SM-3-MCH manufactured by Suga Test Instruments. The color tone was evaluated using the lightness index L and the chromaticness indexes a and b according to the Hunter's color difference equation. Table 3 shows the results. In addition, the strength (tensile strength and proof stress) of each plate was examined, and the results are also shown in Table 3.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

As shown in Table 3, the rolled sheets obtained by the production numbers 1 and 2 having both the alloy component composition and the production process conditions falling within the ranges specified in the present invention have the L value of the color tone after the anodizing treatment, a value, b value is in the range described above, also
The gloss was extremely low, indicating that a sufficient matte black color tone was obtained. On the other hand, the rolled sheets obtained by the production numbers 3 to 6 in which any of the alloy component composition and the production process conditions are out of the ranges specified in the present invention have the L value, the a value, and the b value of the color tone after the anodizing treatment. It can be seen that one or more of the values were out of the above-mentioned range, and that sufficient black was not obtained.

Here, precipitates were examined on the rolled sheet after the artificial aging treatment obtained as described above. That is, a photograph obtained by an electron microscope was processed by an image analysis processor, and the average precipitate size and the average precipitate density were examined, and the precipitate was chemically analyzed. The results are described below in relation to the color tone after the anodizing treatment.

It has been found that the rolled materials manufactured by Production Nos. 1 to 3 using the alloy No. 1 or Alloy No. 2 had Al ₆ Mn-based precipitates in most of the precipitates. Among them, production numbers 1 and 2, which are the invention process,
In the rolled sheet obtained by (1), the distribution density of precipitates having a size in the range of 0.05 to 1.2 μm is 1 × 10 ⁵ to 1 × 1.
It was found 0 is ^six / mm ^2. Therefore, in these cases, a black color sufficient as a color tone after the anodizing treatment was obtained. On the other hand, in the rolled sheet obtained by the production number 3 which is a comparative process, the size of the precipitate is almost 0.
It was less than 01 μm. This is because in Production No. 3, the ingot heating temperature was as low as 350 ° C., so that Al ₆ Mn-based precipitation was not sufficiently performed. In this case, if the color tone after the anodizing treatment was sufficiently black, Did not. When the alloy of alloy No. 3 which is a comparative alloy is used (manufacturing number 4), the manufacturing process itself satisfies the conditions specified in the present invention, but since the amount of Mn is too small, Al ₆ Mn is used.
The precipitation amount of the system is small, and Al in the range of 0.01 to 3 μm
₆ Density of Mn-based precipitates is less than 1 × 10 ⁴ cells / mm ^2, sufficient black after anodization Again was not obtained. Furthermore, when the alloy of alloy No. 4 as a comparative alloy was used (manufacturing number 5), the amount of Cu was large, so that Al-
Almost all Mn-based intermetallic compound precipitates are Cu ₂ Mn ₃ A
It becomes l ₂₀ system, the distribution density of Al ₆ Mn-based precipitates 1 ×
It will be 10 less than ⁴ / mm ^2, in this case, not only is not a sufficient black color tone after the anodic oxidation treatment, has become a strong yellowish cast. And when the alloy of alloy number 5 consisting of the conventional 7075 alloy is used (production number 6)
Showed almost no Al ₆ Mn-based precipitate, and in this case also, no black color tone was obtained after the anodizing treatment.

On the other hand, from the viewpoint of strength, in the case of the rolled materials manufactured by Production Nos. 1 and 2 satisfying the range of the present invention in both the alloy component composition and the production process conditions, the proof stress is 250 N.
/ Mm ² . On the other hand, although the alloy of alloy number 1 which is the invention alloy is used, the rolled material obtained by manufacturing number 3 in which the heating temperature of the solution treatment was as low as 380 ° C. has a proof strength of 250 N / mm ² . Although exceeded, only low strength was obtained as compared with the case according to the present invention. Further, in the case of the rolled material according to the production number 4, since a comparative alloy (alloy number 3) in which the amount of Mg contributing to the strength was too small was used, only a low strength of less than 250 N / mm ² in yield strength was obtained. In addition, although the rolled materials obtained by Production Nos. 5 and 6 had high strength, as described above, a sufficient black color tone as the color tone after the anodizing treatment was not obtained.

As described above, when the component composition conditions and the manufacturing process conditions of the present invention are satisfied, a sufficient black color tone can be obtained as a color tone after anodizing treatment, and at the same time, 250 N /
It can be seen that a high-strength material reliably exceeding mm ² can be obtained. If any one of the alloy component composition condition and the manufacturing process condition deviates, at least one of the color tone and the strength after the anodizing treatment does not satisfy the required characteristics.

Further, the color fading property after the anodizing treatment was examined, and the results are described below. That is, a plate after the anodizing treatment by the sulfuric acid bath obtained by the above-mentioned production number 1 (material of the present invention) and a plate after the anodizing treatment by the sulfuric acid bath obtained by the production number 6 (conventional material: 7075 alloy) To a plate dyed black with a dye against JISD
0205 (1988), exposure for one month with a sunshine weather meter (carbon arc lamp, 63 ° C.,
Dew cycle), and the change in color tone was examined. Table 4 shows the results of examining the L value of the surface before and after the exposure.

[0058]

[Table 4]

As shown in Table 4, in the case of the conventional material, the black color obtained by dyeing was faded by one month of exposure, whereas in the case of the material of the present invention, the black color tone was faded by one month. However, no fading was observed. This is because the material of the present invention develops the color of the anodic oxide film itself, and thus does not cause change or fading due to ultraviolet rays.

Example 2 For the alloys No. 1 and No. 2 shown in Table 1, the same process conditions as in Example 1 were applied until hot rolling, and a hot-rolled sheet having a thickness of 4 mm was obtained. Obtained. Each hot-rolled sheet was further subjected to cold rolling to obtain a cold-rolled sheet having a thickness of 2 mm. Thereafter, using a continuous solution treatment furnace, 480 ° C.
Perform solution treatment for 3 minutes and spray with water for about 10 minutes.
It was cooled at a cooling rate of 00 ° C./sec, and was corrected by a leveler. After leaving it at room temperature for one week,
An artificial aging treatment was performed for 24 hours.

The rolled sheet after the artificial aging treatment was subjected to anodizing treatment in the same manner as in Example 1, and the color tone after the anodizing treatment and the strength were examined. Table 5 shows the results.

[0062]

[Table 5]

For each rolled sheet after the artificial aging treatment,
When the precipitation state of the precipitate was examined in the same manner as in Example 1,
It was confirmed that Al ₆ Mn-based precipitates having a size of 0.05 to 1.2 μm were dispersed at a density of 1 × 10 ⁵ to 1 × 10 ⁶ / mm ² .

Therefore, from this example, even when cold rolling is performed after hot rolling, it is possible to obtain a high-strength rolled material having a black color tone after anodic oxidation treatment and a proof stress of more than 250 N / mm ^2. it is obvious.

Example 3 An alloy having the composition shown in Table 6 was melted according to a conventional method and cast into a billet having a diameter of 8 inches by a DC casting method. 550 ° C for the obtained billet
After being subjected to homogenizing heating for 10 hours, it was cut out and hot-extruded at 400 ° C. to obtain an extruded plate having a cross-sectional dimension of 3 mm × 50 mm. Immediately after extrusion, the cooling rate is 5 ° C / mi by forced air cooling.
Cooled with n. Here, 550 ° C. × 1 for the billet
The 0 hour homogenization heating also serves as the precipitation treatment specified in the present invention, and the hot extrusion and the subsequent cooling also serve as the solution treatment-quenching. As described above, for the sheet material extruded hot, 120 ° C ×
An artificial aging treatment for 24 hours was performed.

Anodizing treatment was performed in the same manner as in Example 1 to check the color tone and the strength. Table 7 shows the results.

[0067]

[Table 6]

[0068]

[Table 7]

As is clear from Table 7, also in the case of the extruded material, the color tone after the anodizing treatment is black and the proof stress is 250 N / mm ² by satisfying the alloy component composition conditions and the manufacturing process conditions specified in the present invention. A material having the above high strength was obtained. Note that it was confirmed that the precipitates also satisfied the conditions described above.

[0070]

As is apparent from the above-described embodiment, according to the present invention, the anodizing treatment can be carried out stably and surely to have a dark gray to black and matte color tone and a proof stress of 25%.
An aluminum alloy wrought material having a high strength of 0 N / mm ² or more can be obtained. And in wrought aluminum alloys of the present invention, since exhibiting a dark gray-black remains anodizing a color tone of the anodic oxide film itself dull, as described above, there is no possibility of discoloration due to ultraviolet rays, etc., and Since it has high strength, it is also suitable for precision machined parts, and is therefore useful for parts of semiconductor devices such as pellicle frames, various optical machines, and the like.

Claims (7)

(57) [Claims] 1. It contains Mn 1.0 to 2.5% (weight%, the same applies hereinafter), Mg 2.16 to 4.0%, Zn more than 5.5% and 9.5% or less. Cu is less than 0.3%, Si less than 0.2% Fe is restricted to less than 0.3%, the balance being from unavoidable impurities other than Al and above, yet among the intermetallic compound precipitates Al ₆
As Mn-based precipitates, those having a size in the range of 0.01 μm to 3 μm are dispersed at a density of 1 × 10 ⁴ particles / mm ² or more, and have a proof stress of 250 N / mm ^2.
A high-strength aluminum alloy wrought material which is as described above and has a matte dark gray to black color after anodizing. 2. Mn 1.0-2.5%, Mg 2.16-
4.0%, containing more than 5.5% Zn and 9.5% or less;
Further, Cu as an impurity is less than 0.3% and Si is 0.1%.
Less than 2%, Fe is less than 0.3%, the balance is Al
And casting an aluminum alloy consisting of unavoidable impurities other than the above, and further performing wrench processing to obtain a wrought material, at any stage after casting, at a temperature within the range of 400 to 550 ° C. After performing the precipitation treatment of heating for up to 24 hours, the material after stretching is heated to a temperature in the range of 400 to 550 ° C. after the precipitation treatment or also as the precipitation treatment, and the temperature is 20 ° C./min or more. Characterized by performing solution treatment-quenching at a cooling rate of 2
A method for producing a wrought high-strength aluminum alloy material having a color tone of 50 N / mm ² or more and having a dull color from dark gray to black after anodizing. 3. The method according to claim 2, wherein the drawing is performed by hot working, the precipitation is performed by ingot heating prior to hot working, and the solution treatment-quenching is performed. 20 ° C / mi immediately after hot working
cooling at a cooling rate of not less than n or at a cooling rate of not less than 20 ° C./min by heating to 400 to 550 ° C. again after hot working;
A method for producing a wrought high-strength aluminum alloy material having a color tone of 50 N / mm ² or more and having a dull color from dark gray to black after anodizing. 4. The method according to claim 3, wherein the hot working is performed by hot rolling, wherein the proof stress is 250 N / mm ² or more and the color tone after the anodizing treatment is no. A method for producing a high-strength wrought aluminum alloy having a gloss of dark gray to black. 5. The method according to claim 3, wherein the hot working is performed by hot extrusion, wherein the proof stress is 250 N / mm ² or more and the color tone after the anodizing treatment is no. A method for producing a high-strength wrought aluminum alloy having a gloss of dark gray to black. 6. The method according to claim 2, wherein the drawing is performed by hot rolling and cold rolling, and the precipitation is performed by heating an ingot prior to hot rolling. Quenching treatment, characterized in that quenching is performed on the cold-rolled sheet after cold rolling, with a proof stress of 250 N
/ Mm ² or more and a method for producing a wrought high-strength aluminum alloy material having a matte dark gray to black color after anodizing. 7. The method according to claim 2, wherein after the solution treatment-quenching, heating is performed at a temperature in the range of 80 to 200 ° C. for 1 to 48 hours. A method for producing a wrought high-strength aluminum alloy material having a proof strength of 250 N / mm ² or more and a matte dark gray to black color after anodizing, which is characterized by performing aging treatment.