JP2858068B2 - Light-colored thick aluminum alloy rolled sheet for building materials with stable color tone after anodizing and 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 relates to a thick aluminum alloy material having a thickness of 3 mm or more, which is used after being subjected to anodizing treatment, and more particularly to a thick aluminum alloy used as a building material such as a curtain wall of a building or an interior material. The present invention relates to an alloy plate and a method for manufacturing the same.

[0002]

2. Description of the Related Art Aluminum alloys generally used for building materials such as curtain walls of buildings, other building exterior materials, and building interior materials are subjected to anodizing treatment mainly from the viewpoint of corrosion resistance. There are many.

[0003] Conventionally, as an aluminum alloy for building materials which is used after being subjected to anodizing treatment, there are many alloys whose color tone after the anodizing treatment is from light gray to silver, and in this case, the type of alloy is as follows. Generally, JIS 1050
Alloy, 1100 alloy, 5005 alloy or the like is often used. In addition, as a material having a gray color after anodizing, Al-1 to 4% Si alloy is generally used.

[0004] Conventionally, in the production process of this type of aluminum alloy, intermediate annealing is performed in the middle of cold rolling or between hot rolling and cold rolling. The color tone and the surface texture after the anodizing treatment are made uniform by this, and the flatness is adjusted by the subsequent cold rolling, so-called H14.
It is common to use a product plate as a temper material.

[0005]

Among the uses of various types of aluminum alloy sheets for building materials, there are design requirements for strength,
Alternatively, it may be necessary to use a thick rolled plate having a plate thickness of 3 mm or more due to design requirements or the like.

However, when such a thick material is manufactured, if intermediate annealing is performed in the same manner as in a conventional general method,
Because the cold rolling reduction before the intermediate annealing cannot be increased too much, the recrystallized grains during the intermediate annealing become coarse, and the surface is roughened by the subsequent anodizing treatment, so that it cannot be accepted as a product. There is a possibility that it will. On the other hand, when the intermediate annealing is not performed, the influence of the ingot structure and the hot-rolled structure is likely to remain on the final sheet, so that the surface tends to be uneven (pattern), and the anodic oxidation due to the fluctuation of the amount of precipitated Si. There is also a problem that it is difficult to control the color tone after the processing.

On the other hand, when obtaining a thick material having a thickness of 3 mm or more,
In some cases, cold rolling is not performed, and the product sheet remains as it is after hot rolling.However, if hot rolling is completed, the effect of the ingot structure is likely to remain on the product sheet, and the effect of the hot rolling structure is reduced. Since it remains on the product plate as it is, surface irregularities such as streaks are likely to occur, and it is difficult to control the color tone after the anodic oxidation treatment due to fluctuations in the amount of precipitated Si. In addition, when the hot-rolling is performed as described above, it is difficult to secure many surface defects and to maintain flatness. Furthermore, since the hot-rolled plate also has a different surface dislocation density from the plate made of H14 temper material by cold rolling, a difference in surface gloss occurs, and the color of the surface after anodizing is also reduced. It will be different from H14 temper material. Therefore, when a thin plate made of H14 temper material by cold rolling and a thick plate as hot rolled are mixed and used in the same building or the like, the uniformity of the color appearance is lost, and the appearance of the building is reduced. It may be damaged.

The present invention has been made in view of the above circumstances, and has been applied to a rolled aluminum alloy plate for a building material which is used by performing anodizing treatment, particularly a thick plate having a plate thickness of 3 mm or more, and a color tone after the anodizing treatment. Is light-colored (light gray), stable and has the same color sensation as the conventional H14 temper material, and has no color unevenness, pattern, or streak on the surface after the anodizing treatment, and further has a rough surface. It is an object of the present invention to provide a rolled aluminum alloy sheet having less appearance characteristics.

[0009]

The present inventors have conducted intensive experiments and studies in order to solve the above-mentioned problems. As a result, not only are the components of the aluminum alloy properly regulated, but also the hot rolling conditions Is appropriately controlled to obtain a cold-rolled ascended sheet without intermediate annealing, thereby appropriately adjusting the amount of precipitated Si and simultaneously adjusting the flatness of the crystal grains of the final sheet. The inventors have found that the problem can be solved, and have accomplished the present invention.

[0010] Specifically, the thick aluminum alloy rolled sheet for building material according to the first aspect of the present invention has an Fe content of 0.20 to 1.3%,
It contains 0.05 to 0.30% of Si and 0.003 to 0.15% of Ti alone or in combination with 0.5 to 150 ppm of B or 0.1 to 150 ppm of C as a grain refiner, with the balance being the balance. Is composed of Al and unavoidable impurities, the amount of precipitated Si is 0.03% or less, and the ratio of length / width of crystal grains in a plane parallel to the rolled surface is 3 or more on average. Is what you do.

The rolled aluminum alloy sheet for building material according to the second aspect of the present invention is characterized in that: 0.20-1.3% Fe, 0.05% Si
-0.30%, 0.05-0.30% Cu, and 0.003-0.15% of Ti alone or 0.5-150 ppm of B or C0.1-
150 ppm in combination with the balance consisting of Al and unavoidable impurities, the amount of precipitated Si is 0.03% or less, and the ratio of the length / width of the crystal grains in the plane parallel to the rolling plane is average. Is 3 or more.

Further, the method for producing a rolled aluminum alloy sheet for building materials according to the third aspect of the present invention is characterized in that:
0.05 to 0.30% of Si, and 0.003 to 0.15% of Ti alone or in combination with 0.5 to 150 ppm of B or 0.1 to 150 ppm of C as a grain refiner; Cu 0.05- if necessary
An alloy containing 0.30%, with the balance being Al and unavoidable impurities, was cast so that the average crystal grain size in the ingot was 500 μm or less.
The soaking is performed for 1 to 24 hours, and the ingot is subjected to beveling before or after the soaking, and further hot rolling is performed.
And the hot rolling end temperature is controlled to be in the range of 200 to 330 ° C., and then cold rolling is performed at a rolling reduction of 1% or more without performing intermediate annealing to obtain a surface parallel to the rolling surface. In which a rolled plate having a length / width ratio of crystal grains of 3 or more on average is obtained.

[0013]

In the aluminum alloy sheet for building materials of the present invention, the color tone after the anodizing treatment is basically made lighter (lighter) by strictly defining the component composition, particularly Fe and Si, and at the same time, regulating the amount of precipitated Si. Gray), stabilize its color tone, and further define the ratio of length / width in the plane parallel to the rolling plane of the crystal grains of the final sheet, ie, the flatness of the crystal grains, thereby anodizing. Surface irregularities and patterns during processing are reduced.

In the method of manufacturing a thick aluminum alloy rolled sheet for building materials according to the present invention, basically, the ingot crystal grain size is regulated to refine the ingot structure, and the soaking conditions are appropriately adjusted. It is set so that a light color tone is obtained after anodizing treatment, and further, the hot rolling conditions are appropriately regulated so that only one cold rolling is performed thereafter without performing intermediate annealing. By doing so, the surface roughness and color tone unevenness after the anodizing treatment are prevented from occurring, and the color appearance is made the same as that of a conventional ordinary cold-rolled material (H14 tempered material).

First, the reasons for limiting the component composition in the present invention will be described.

Fe: Fe is an important element that forms an Al—Fe intermetallic compound and determines the color tone after anodizing treatment. In particular, by appropriately setting the soaking conditions, Al ₃ Fe An intermetallic compound is obtained, which contributes to lightening the color tone after anodizing. If Fe is less than 0.20 wt%, the color tone becomes too thin as a whole, and the gloss of the surface after the anodizing treatment increases, and it cannot be said that a sufficient color tone is obtained. On the other hand, if Fe exceeds 1.3% by weight, coarse Al-Fe-based intermetallic compound crystallites increase, and the color tone after anodizing treatment becomes yellowish. Therefore, the amount of Fe is 0.20 to 1.3 wt%.
Within the range.

Si: Si is added for adjusting the strength and the color tone after the anodizing treatment. As for the color tone, Si is
It forms a solid solution in Al ₃ Fe and affects the color tone, and also precipitates as a precipitated Si phase depending on the temperature conditions during the manufacturing process, which also affects the color tone. Si content is 0.
If the content is less than 05% by weight, the color tone after the anodizing treatment is too shallow and the metallic luster on the surface becomes large, so that a sufficient color tone cannot be obtained.
On the other hand, if the Si content exceeds 0.30 wt%, αAlFeSi
A phase is formed, and the color tone after the anodizing treatment becomes yellowish, and the color tone fluctuates. Further, precipitated Si is generated to cause unstable color tone. Therefore, the amount of Si is 0.05-0.
It was within the range of 30 wt%.

Cu: Cu is not positively added in the rolled aluminum alloy sheet of the invention of claim 1, but is an effective element for improving the strength. Therefore, Cu is added in the rolled aluminum alloy sheet of the invention of claim 2. . However, Cu gives a slightly yellowish color tone after the anodizing treatment. If the Cu content is less than 0.05 wt%, the effect of improving the strength by the active addition of Cu cannot be obtained, while if it exceeds 0.30 wt%, the corrosion resistance is reduced and the color tone after anodizing becomes yellowish. It becomes inappropriate. Therefore, in claim 2, Cu
The amount was in the range of 0.05 to 0.30 wt%.

Ti, B, C: Ti has the effect of minimizing ingot crystal grains and preventing texture and streaks of the rolled sheet. On the other hand, B coexists with Ti and exhibits the effect of refining ingot crystal grains. C also exhibits an ingot crystal grain refinement effect in coexistence with Ti. Therefore, Ti was added alone, in combination with B, or in combination with C as a grain refiner. If Ti is less than 0.003 wt%, the effect of grain refinement cannot be obtained, while if Ti exceeds 0.15 wt%, a coarse intermetallic compound of TiAl ₃ may be generated. 003-0.15wt%
Within the range. If B is less than 0.5 ppm, the effect of refining crystal grains due to coexistence with Ti cannot be obtained, and B
If m is exceeded, linear defects due to coarse TiB ₂ particles will occur, so the amount of B when added in combination with Ti is 0.5 to
It was within the range of 150 ppm. Further, if C is less than 0.1 ppm, the effect of refining crystal grains due to coexistence with Ti cannot be obtained,
If C exceeds 150 ppm, coarse graphite may be mixed and defects may occur. Therefore, when C is added in combination with Ti, the amount of C is set in the range of 0.1 to 150 ppm.

In addition to the above elements, Al and unavoidable impurities may be basically used. However, in general, a small amount of Be may be added to a normal aluminum alloy in order to prevent the molten metal from being oxidized during casting. However, in the case of the present invention, the addition of a small amount of Be does not particularly deteriorate other performances. Addition of Be of about 500 ppm or less is allowable. Also, Mg and Zn do not degrade other performances if they are each 1.0 wt% or less. Therefore, it is permissible to contain each of 1.0 wt% or less.

Furthermore, in the thick aluminum alloy rolled sheet for building materials of the present invention, it is important to regulate the amount of precipitated Si. That is, if the precipitated Si particles exist,
The yellow tone becomes stronger in the color tone after anodizing treatment, and moreover, if a large amount of Si is deposited, it becomes difficult to control the amount of deposition, and the color tone after anodizing treatment tends to fluctuate. Color unevenness is likely to occur. Especially precipitated Si
If the amount exceeds 0.03% by weight, color unevenness is likely to occur after the anodizing treatment. Therefore, the amount of precipitated Si is limited to 0.03% by weight or less.

Further, in the thick aluminum alloy rolled sheet for building materials of the present invention, the crystal structure in the state of the product sheet is important. That is, the rolled aluminum alloy plate of the present invention is:
After hot rolling, a product sheet is formed by one cold rolling without intermediate annealing. In this case, if recrystallization occurs in the final sheet thickness in hot rolling or in a pass near it, ,
The surface structure of the product plate becomes uneven, and the surface after the anodic oxidation treatment becomes uneven. The degree of such unevenness of the structure and the occurrence of unevenness after the anodic oxidation treatment are almost correlated with the length / width ratio (flatness) of a plane parallel to the rolling plane of the crystal grains of the product sheet. If the degree of flattening is less than 3, the surface structure becomes non-uniform and unevenness is likely to occur after the anodizing treatment. Therefore, the aluminum alloy plate of the present invention needs to have the flatness of 3 or more. The flatness of the crystal grains of such a product sheet can be achieved by appropriately adjusting each process condition such as a hot rolling condition as described later.

Next, a method of manufacturing a thick-walled aluminum alloy rolled sheet for building materials of the present invention and each process condition will be described.

First, an alloy having the above-described composition is cast by a DC casting method (semi-continuous casting method) or the like. In this casting, it is important to obtain a uniform and fine ingot structure. That is, since the intermediate annealing is not performed in the production method of the present invention, slight unevenness of the structure leads to unevenness and pattern after the anodizing treatment. Therefore, it is necessary to make the structure uniform and fine from the ingot stage. is there. If the grain size of the crystal grains in the ingot becomes larger than 500 μm, the unevenness after the anodic oxidation treatment becomes apparent as described above, so it is necessary to regulate the crystal grain size to 500 μm or less.
And in order to achieve such ingot crystal grain refinement,
In the present invention, as described above, Ti as a grain refiner,
Alternatively, Ti and B, or Ti and C are added, but the casting speed during casting is also preferably 30 mm / min or more. Also, in the ingot cross-section, when the anodizing treatment produces a structure in which the boundary between the outer dark color portion and the inner light color portion shows a fir tree structure, that is, a so-called fir tree structure, If a floating crystal is formed, a pattern or unevenness occurs after the anodizing treatment of the final rolled sheet. Therefore, it is desirable to control the structure so that these abnormal structures do not occur.

After casting, the surface of the ingot is subjected to facing, and then subjected to soaking treatment described below, or the soaking process is applied and then facing. That is, if the chill layer or the coarse cell layer existing on the surface of the ingot remains, they also cause a pattern or unevenness after the anodizing treatment. It is necessary to sharpen.
Generally, the thickness at which the chill layer or the coarse cell layer exists is 10 mm.
Before and after, therefore, it is sufficient that the chamfering is performed about 15 mm from the surface. Also, this facing is usually performed on a wide
It only has to be done on the surface.

The soaking is performed at a temperature in the range of 500 to 630 ° C. for 1 to 24 hours. This soaking is not only necessary for the purpose of general homogenization of the ingot structure, but also important for obtaining a light color tone as the color tone after the anodizing treatment. That is, the intermetallic compound Al ₆ Fe which crystallized during casting is transformed into Al ₃ Fe by soaking, can exhibit the color tone of light color (light gray) color tone after anodizing by the presence of the Al ₃ Fe . If the soaking temperature is lower than 500 ° C., Al ₆ Fe crystallized matter remains, and a light color tone cannot be obtained after the anodizing treatment of the product plate. On the other hand, if the temperature exceeds 630 ° C., the crystal grains become coarse and the final plate becomes Even in the state where the anodic oxidation treatment has been performed, unevenness and patterns occur. On the other hand, if the soaking time is less than 1 hour, the above-mentioned effects cannot be sufficiently obtained. On the other hand, a long soaking time exceeding 24 hours is only economically useless.

After soaking (or after facing if soaking is performed), hot rolling is started using the retained heat of soaking without cooling, or once cooled, Reheat and perform hot rolling. These hot rolling conditions are extremely important in the manufacturing process of the present invention in which no intermediate annealing is performed. In other words, since the intermediate annealing is not performed in the process of the present invention, if coarse recrystallization occurs during hot rolling, the influence of the coarse recrystallized grains remains up to the final rolled sheet, and unevenness and patterns may occur after anodizing. In particular, if coarse recrystallization occurs in a pass close to the final stage of hot rolling, the effect remains strong and unevenness and patterns after anodizing treatment are likely to occur. In addition, even when recrystallization occurs partially during winding after hot rolling or in the state of the coil after that, the effect remains strong, and unevenness and patterns after anodizing are likely to occur. In order to solve such a problem, it is necessary to recrystallize finely during the hot rolling process,
In particular, it is important to prevent the occurrence of coarse recrystallization at a stage near the final pass, and to prevent partial recrystallization during and after winding of the sheet after hot rolling. Therefore, in the production method of the present invention, the temperature of the sheet is set to 400 ° C. or less at the stage where the thickness of the sheet during hot rolling is 50 mm, and the hot rolling end temperature is set in the range of 200 to 330 ° C. I decided to control it. By lowering the temperature at the stage of 50 mm thickness in the middle of hot rolling and lowering the hot rolling end temperature in this way, after the anodizing treatment of the product sheet due to the influence of coarse recrystallization or partial recrystallization, It has become possible to effectively prevent the uniformity of the surface from being impaired and to cause unevenness and patterns.

In the case where the hot rolling is performed at a high temperature exceeding 400 ° C. at the stage of the thickness of 50 mm during the hot rolling, large recrystallized grains are generated in the subsequent pass and remain on the product sheet as described above. It causes unevenness and pattern. At a high temperature at which the hot rolling end temperature exceeds 330 ° C., recrystallization occurs partially during or after winding of the rolled sheet, and the uniformity of the surface after anodizing treatment is impaired, resulting in unevenness. , And a pattern occurs. On the other hand, when the hot rolling end temperature is lower than 200 ° C., Si precipitates during and after coil winding, and flaws and the like due to rolling are likely to occur. As described above, in order to control the plate temperature at the stage where the plate thickness is 50 mm to be 400 ° C. or less, the starting temperature of hot rolling may be lowered, or cooling may be performed during hot rolling. A method may be applied. In addition, the thickness of the ingot subjected to hot rolling is usually about 300 to 700 mm, and the sheet thickness at the end of hot rolling is usually about 3 to 15 mm.

After the completion of hot rolling, cold rolling of 1% or more is performed without intermediate annealing to obtain a product sheet. By performing cold rolling in this way, the flatness of the sheet is improved, and surface flaws during hot rolling can be eliminated, and the surface is subjected to cold working. Is the same as the H14 temper material applied to the thin material of H14, and the color appearance after the anodic oxidation treatment is also H14.
Since it is the same as the tempered material, even if the same building is mixed with a thin-walled material of H14 temper, the unification of the overall color appearance does not collapse.

Here, if intermediate annealing is performed, in the present invention, since the final sheet is a thick material, it is not possible to obtain a large cold working ratio before the intermediate annealing, so that the crystal grains are coarse during the intermediate annealing. And the surface after the anodic oxidation treatment becomes rough. On the other hand, if a product plate is formed as hot rolled without performing cold rolling, the flatness of the plate becomes insufficient, and the surface flaw during hot rolling remains as it is. Further, since the dislocation structure on the surface is different from that of the H14 temper material used for the conventional thin material when hot rolling is performed, the color appearance of the surface after the anodizing treatment is different from that of the H14 temper material. Therefore, in the present invention, cold rolling is performed after hot rolling without intermediate annealing. If the cold rolling reduction is less than 1%, the above-mentioned effects cannot be obtained.
% Or more, and preferably 5% or more. Although the upper limit of the cold rolling reduction is not particularly defined, the purpose of obtaining a thick material of 3 mm or more,
In consideration of the thickness of the hot rolled sheet and the thickness of the hot rolled sheet, it is usually set to 30% or less.

The rolled plate (product plate) obtained through the above process has a structure in which the flatness of crystal grains (length / width ratio in a plane parallel to the rolled surface) is 3 or more. Thus, the surface after the anodizing treatment is uniform, there is little possibility of unevenness, pattern, etc., and the color tone is light (light gray) and stable.

The anodic oxidation treatment may be performed according to a conventional method. However, it is advantageous to use a sulfuric acid electrolytic bath from the viewpoint of economy and corrosion resistance. In the rolled sheet obtained as described above, the sulfuric acid electrolytic bath is used. A light color (light gray) can be obtained as described above by anodizing treatment using a bath.

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 can be formed by using a sulfuric acid bath having a bath temperature of 15 to 30 ° C., a current density of 0.5 A / dm ² or more and less than 3.0 A / dm ² using a sulfuric acid bath of 〜25 vol%. desirable.

The color tone after the anodizing treatment can be evaluated by the values of the lightness index L and the chromaticness indexes 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 is, the whiter the color index is, while the higher the a value of the chromaticness index is, the stronger the reddish color, and the higher the b value, the stronger the yellowish color. The light color (light gray) intended in the present invention is defined as follows.

L value> 60-2 <a value <2-2 <b value <4

[0036]

EXAMPLE Alloy No. 1 shown in Table 1 was used. 1 to No. Each alloy of No. 4 is 450mm thick and 1200m wide by DC casting method
m, and cast into a slab having a length of 4000 mm. In addition, as an ingot crystal grain refiner, 5% Ti-1% B was used. Table 2 shows the results of examining the ingot structure of each slab.

Each alloy No. 1 to No. The slab No. 4 was subjected to a soaking treatment under the conditions shown in Table 3 and then the wide surface was chamfered to a thickness of 15 mm and hot rolled. Hot rolling start temperature of this hot rolling, 50 mm halfway
Table 3 shows the temperature at the stage of and the hot rolling end temperature. The thickness of the hot-rolled sheet was 8 mm or 6 mm. Then, the hot-rolled sheet of 8 mm is cold-rolled to 6 mm without performing intermediate annealing (Production Nos. 1, 2, and 2).
3, 6, 8) or subjected to intermediate annealing at 390 ° C. × 2 hours and cold-rolled to 6 mm (Production No. 4). As for the hot-rolled sheet of 6 mm, a part of the sheet is directly used as a product sheet (manufacture No. 7), and the other is cold-rolled from 6 mm according to a conventional normal sheet manufacturing process to a 3.5 mm thick sheet. Anneal (350 ° C x 2 hours), then 2.5mm
It was cold rolled to a thickness (Production No. 5). For each of the obtained rolled sheets, the amount of precipitated Si and the flatness of crystal grains were examined. The results are also shown in Table 3.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

Further, for each rolled plate, 10% NaOH
After chemical etching with an aqueous solution, washing with water and desmutting with nitric acid. Next, an anodic oxidation treatment was performed using a sulfuric acid electrolytic bath having a sulfuric acid concentration of 10 vol% at a bath temperature of 20 ° C. and a current density of 1.5 A / dm ² to form anodic oxide films each having a thickness of 20 μm.

The surface color tone of each rolled sheet after the anodizing treatment was examined using a color meter SM-3-MCH manufactured by Suga Test Instruments, and evaluated by the L value, a value, and b value according to the Hunter's color difference formula. Similarly, the surface gloss after the anodizing treatment was examined, and the appearance of the surface pattern and the like were visually examined. Table 4 shows the results of these investigations.

[0043]

[Table 4]

As is apparent, the alloys (alloys Nos. 1 to 3) within the component composition range specified in the present invention are subjected to the manufacturing process conditions specified in the present invention, and the grain flatness of the final sheet and the When the amount of precipitated Si satisfies the range defined in the present invention (Production No. 1, No. 3, No. 3).
In 6), it was confirmed that in each case, a light color tone could be obtained as the color tone after the anodizing treatment, the glossiness was small, and no unevenness such as streak patterns and streaks and surface roughness did not occur. . These results are similar to those of the sheet obtained according to the conventional normal sheet process of serial number 5.

On the other hand, in production No. 1 in which the temperature at the stage of the plate thickness of 50 mm in hot rolling and the end temperature of hot rolling were high. 2
In the case of the comparative example, the flatness of the crystal grains of the final plate is small,
Streaks appeared on the surface after the anodizing treatment, and the appearance was determined to be poor. Further, the production No. in which intermediate annealing was performed after hot rolling.
In the case of Comparative Example 4, the crystal grains were coarsened, the flatness of the crystal grains of the final plate was small, and the surface was roughened by the anodizing treatment, resulting in poor appearance. Furthermore, the production No. In No. 7, the hot-rolling end temperature was low and the hot-rolled sheet was raised without performing cold rolling. In this case, the amount of precipitated Si was large, and the color tone of the surface after anodizing was yellowish. As well as increased gloss and surface flaws.
And again, the production No. No. 8 uses a comparative alloy (alloy No. 4) having a small ingot crystal grain refining agent. In this case, the crystal structure of the ingot becomes coarse feather-like crystals. Streak appeared on the surface of the sample, resulting in poor appearance.

[0046]

The rolled aluminum alloy sheet for building material of the present invention is a thick plate having a thickness of 3 mm or more which is used after anodizing, and has a stable light color as the surface tone after the anodizing treatment. It has the same color appearance as H14 temper material used for building materials as a thin-walled material, and has less appearance characteristics such as less occurrence of surface patterns and streaks after anodic oxidation treatment and less surface roughness. It is extremely excellent and has good flatness.

According to the production method of the present invention, a thick aluminum alloy rolled sheet for building material having the above-described excellent appearance characteristics can be stably and easily produced on a mass production scale.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C25D 11/04 308 C25D 11/04 308 // C22F 1/00 601 C22F 1/00 601 604 604 613 613 613 623 623 671 671 673 673 681 681 682 682 683 683 683 685 685Z 691 691B 691C 694 694A 694B (58) Fields investigated (Int. Cl. ⁶ , DB name) C22C 21/00-21/18 C22F 1/04-1/057 C25D 11/04

Claims (3)

(57) [Claims] 1. An alloy containing 0.20 to 1.3% Fe (wt%, the same applies hereinafter), 0.05 to 0.30% Si, and 0.003 to 0.15% Ti alone as a grain refiner. Or B0.5 ~ 150ppm or C0.1 ~ 150pp
m, and the balance consists of Al and unavoidable impurities, the amount of precipitated Si is 0.03% or less, and the ratio of the length / width of the crystal grains in the plane parallel to the rolling plane is average. A thick aluminum alloy rolled plate for building materials having a stable color tone after anodizing treatment and having a stable color tone of 3 or more. 2. 0.20 to 1.3% of Fe, 0.05 of Si
-0.30%, 0.05-0.30% Cu, and 0.003-0.15% of Ti alone or 0.5-150 ppm of B or C0.1-
150 ppm in combination with the balance consisting of Al and unavoidable impurities, the amount of precipitated Si is 0.03% or less, and the ratio of the length / width of the crystal grains in the plane parallel to the rolling plane is average. A thick aluminum alloy rolled plate for building materials having a stable color tone after anodizing treatment and having a stable color tone of 3 or more. 3. 0.20 to 1.3% Fe, 0.05 Si
0.30%, and Ti as a grain refiner
0.003 to 0.15% alone or B0.5 to 1
An alloy containing 50 ppm or 0.1 to 150 ppm of C in combination with 0.05 to 0.30% of Cu as necessary, with the balance being Al and unavoidable impurities having an average crystal grain size in the ingot. And the resulting ingot is subjected to soaking at 500 to 630 ° C. for 1 to 24 hours, and the ingot is subjected to face milling before or after the soaking, and further hot-rolled. At an intermediate stage of the plate thickness of 50 mm so that the plate temperature becomes 400 ° C. or lower and the hot rolling end temperature falls within the range of 200 to 330 ° C., and thereafter, the rolling reduction is 1 without intermediate annealing.
% Or more, and a rolled plate having a length / width ratio of crystal grains in a plane parallel to the rolling plane of 3 or more on average is obtained. The color tone after anodizing is stable. For producing thick, light-colored rolled aluminum alloy plates for building materials.