JPH11335761A - Aluminum alloy sheet excellent in surface property and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy sheet having an excellent surface property by controlling in hot rough rolling of an ingot so that an average grain size of a crystal appeared on a surface of an alloy sheet containing Fe, Si and a grain size in a rolling direction of the crystal having same crystal face come respectively below a specified value. SOLUTION: A content of Fe and Si in an alloy of an Al purity of >=99.0% are respectively made <=0.8 mass % and <=0.5 mass % and, at need, other specified elements such as Ti and B, are contained. An average crystal grain size of an alloy plate surface is set to <=100 μm, a grain size in a rolling direction of an aggregate of one kind among crystal faces 100, 011, 112 or 123 is set to <=10 mm, so that generation of a streak pattern, ribbing mark, etc., are prevented. A hot rough rolling condition is that a rolling start temp. of an ingot subjected to soaking is set to <=450 deg.C, rolling is performed at a rolling speed of >=50 m/min from a start pass condition and at a rolling reduction of >=30 mm or at one pass draft of >=30%, and a completion temp. is 300-370 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy sheet for surface treatment used as a material for interior / exterior panels for buildings, daily necessities, kitchen utensils, supports for lithographic printing plates, etc., and particularly to anodization treatment. The present invention relates to a technique for improving the surface properties of an aluminum alloy plate used after being subjected to a surface treatment such as polishing / grinding, chemical or electrochemical etching.

[0002]

2. Description of the Related Art Pure aluminum alloy plates of industrial purity used for surface treatment (Al purity of 99.0% or more)
JIS-1100, 1200, 1500 and the like are known, and it is required that the surface properties be excellent. Specific criteria for evaluating such surface properties are that the surface quality is excellent to the extent that defects such as grain streaks do not occur on the surface, and that living marks and rough surfaces do not occur on the processed surface. And the like. Here, the grain streak is a streak defect generated on the surface when the product is subjected to the alumite treatment, and the living mark is the striped irregularities generated along the rolling direction when the product is subjected to the drawing process. .

As a method for producing such an aluminum alloy sheet, an alloy ingot obtained by DC casting (semi-continuous casting) is subjected to steps such as homogenization, hot rolling, cold rolling and annealing, or Further, it is generally manufactured by a process in which intermediate annealing is inserted between hot rolling and cold rolling. In order to satisfy the above-mentioned required characteristics in these steps, various attempts have been made so far.

For example, Japanese Patent Application Laid-Open No. 64-31954 discloses that a fibrous structure generated by hot rolling remains as a texture only by annealing, and this causes the generation of grain streaks. In the method of causing recrystallization between the hot rolling passes to eliminate the fibrous structure, the grain streak is increased by increasing the rolling reduction of each hot rolling pass and increasing the rolling temperature. It is disclosed that the occurrence of phenomena can be prevented. Further, as a specific processing condition for that purpose, a process of holding at a temperature of 300 to 450 ° C. for one minute or more between passes after the total reduction amount exceeds 50% is performed.

[0005] JP-A-3-204104, 5-9
No. 675, No. 5-9667 and No. 4-23745, the same cause as in the above-mentioned JP-A-64-31954 is recognized as to the cause of the occurrence of grain streaks.
As means for solving the problem, it is disclosed that a high cold rolling reduction is performed after hot rolling and that annealing conditions are devised.

On the other hand, in the case of building panels and daily necessities, 90
Since bending, overhanging, and drawing are performed at an angle of more than °, the aluminum alloy plate used for these applications must have excellent formability and surface quality after processing. It is said that it is necessary to reduce the crystal grain size of the sheet material in order to improve the crystallinity. Further, it is said that the rough surface generated during the drawing process occurs when the recrystallized particle size of the product is large, and reducing the recrystallized particle size is also useful for preventing the above-described rough surface.

As a technique for improving the surface properties by reducing the crystal grain size, for example, Japanese Patent Application Laid-Open No. Hei 5-320839 has been proposed.
In this technique, it is disclosed that the composition of a chemical component is adjusted and the conditions of final cold rolling, final annealing, and the like are controlled to achieve a finer crystal grain size.

In the case of an aluminum alloy whose surface is polished and ground or subjected to chemical or electrochemical etching treatment, such as when used as a material for a lithographic printing plate support, etc. -There is a problem that uneven grinding and etching occur. As a technique for solving such a problem, for example, JP-A-7-224339 discloses controlling the size and shape of crystal grains. Further, as the thickness of the aluminum plate is required to be small, for example, when the thickness is 1 mm or less, the strength of the plate may cause a problem of insufficient strength or variation in strength.

[0009]

In recent years, the required properties of the surface properties of aluminum alloy sheets have tended to become increasingly severe. However, with the technologies proposed so far, it is not possible to obtain an aluminum alloy plate that can sufficiently meet such demands, and in fact, it is desired to establish a technology for further improving the surface properties.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to prevent occurrence of grain streaks, living marks, and surface roughness, and to provide excellent etching uniformity of a plate. Another object of the present invention is to provide an aluminum alloy plate having excellent surface properties and a useful method for producing such an aluminum alloy plate.

[0011]

The aluminum alloy plate according to the present invention, which can solve the above-mentioned problems, is an aluminum alloy plate containing Fe and Si, and is an average of the crystal appearing on the surface of the alloy. The particle size is 100 μm or less, the size of the aggregate having the same crystal plane,
It has a gist in that it is 10 mm or less in the rolling direction. In this aluminum alloy plate, the aggregate includes (100) plane, (011) plane, (112) plane,
Preferably, it is an aggregate of crystal grains showing any one of the (123) planes on the surface.

The aluminum alloy plate targeted in the present invention is assumed to be a pure aluminum alloy plate of industrial purity and contains small amounts of Fe and Si as basic components. The content of Si is
0.8% by mass or less (not including 0% by mass) and 0.5% by mass, respectively.
It is preferable that the content is not more than 0% by mass (not including 0% by mass). If necessary, it is also useful to include the following components (a) to (d), whereby the properties of the aluminum alloy sheet can be further improved.

(A) Ti: 0.1% by mass or less (0% by mass)
And / or B: 0.1% by mass or less (0%
(B) Cu: 0.5% by mass or less (excluding 0% by mass)
And / or Mn: 0.5% by mass or less (not including 0% by mass) (c) Mg: 0.5% by mass or less (excluding 0% by mass) (d) Cr: 0.3% by mass or less ( (Not including 0% by mass)
And / or Zr: 0.3% by mass or less (excluding 0% by mass)

On the other hand, in producing the aluminum alloy of the present invention as described above, the ingot is subjected to a soaking treatment, and then the rolling start temperature is set to 450 ° C. or less, and 5 minutes from the start pass.
Hot rough rolling at an end temperature of 300 to 370 ° C. may be performed at a rolling speed of 0 m / min or more and satisfying either a reduction amount of 30 mm or more or a one-pass reduction ratio of 30% or more. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied from various angles the cause of the insufficient surface quality of a conventional aluminum alloy plate. As a result, they found that insufficient control of the distribution state of the crystal plane was the cause of the deterioration of the surface properties. In addition, the present inventors have variously changed the crystal orientation distribution state, investigated the relationship with the presence or absence of the occurrence of grain streaks, and studied the mechanism of its occurrence, it is the same that deteriorates the surface quality is the same It was also found that the crystal plane had a structure elongated in the rolling direction. Based on these ideas, further investigations were made on specific means for improving the surface properties, and it was found that if the above-described configuration was employed, the above-mentioned object could be achieved brilliantly, and the present invention was completed. did.

First, the requirements specified in the present invention will be described. In the aluminum alloy plate of the present invention, it is necessary that the average grain size of the crystal appearing on the surface is 100 μm or less. When this value exceeds 100 μm, not only the etching surface quality becomes coarse, but also the surface becomes rough after forming. The average particle size of the crystals is preferably 80 μm or less.

It has also been found that the rough surface after the forming process is associated with the aggregate having the same crystal orientation in some form.
In this regard, in the prior art, each crystal grain size is 5
Although it is considered to be acceptable if the thickness is 0 μm or less, it is possible to provide a plate with suppressed surface roughness even with a crystal grain size of up to about 100 μm by dispersing the aggregate. The “crystal grain size” in the present invention is a value measured by a line intercept method in a direction perpendicular to the rolling direction.

In the present invention, “the size of an aggregate having the same crystal plane” means that an aggregate having the same crystal plane elongated in the rolling direction (this point will be described later) is observed by a stereoscopic microscope or microstructure observation. When the ratio of the same crystal plane per 1 mm ² becomes 30% or less in area ratio, it is regarded as the end of the aggregate, and the distance in the rolling direction between them is defined as the aggregate size. This is because, when the area ratio is 30% or less, the crystal orientation is dispersed, and the appearance does not cause a poor appearance such as a stripe pattern. In the present invention, the area ratio is obtained by analyzing the same crystal plane by the above method, performing color coding of the same crystal orientation, and performing image processing on the color. A preferable upper limit of the area ratio is 25%.

When the aggregate size of the same crystal plane defined as described above is 10 mm or less in the rolling direction, it is possible to prevent the generation of streaks or living marks on the surface. When this aggregate size is larger than 10 mm,
Appearance defects such as uneven etching and streaks occur. The size of the aggregate is preferably 9 mm or less, more preferably 8 mm or less. The formation of such an aggregate occurs not only in the processed structure after rolling, but also in the partially recrystallized structure and the recrystallized structure after annealing.

The aluminum alloy plate of the present invention has a preferable configuration in which the crystal plane on the surface and its texture are specified. Next, these concepts will be described. In a normal aluminum alloy plate, Cube
A texture called an orientation, a Goss orientation, a Brass orientation, a Copper orientation, or an S orientation is formed, and a crystal plane corresponding to these is present. Here, the formation of the texture differs depending on the processing method even for the same crystal system, and in the case of a rolled sheet material, it is necessary to express it by a rolling surface and a rolling direction. The rolling surface is represented by ｛, and the rolling direction is represented by <△△△> (○ and 示 す indicate integers). Based on such an expression method, each direction is represented as follows. Cube orientation ｛001｝ <100> Goss orientation ｛011｝ <100> Brass orientation ｛011｝ <211> Copper orientation ｛112｝ <111> S orientation ｛123｝ <634>

That is, it is considered that when the etching rate differs depending on the crystal plane and the distribution state in the plate surface changes, the surface irregularities change and the surface properties deteriorate. In the present invention, basically, ± 20 ° from these crystal planes
Orientation deviations within are defined as belonging to the same crystal plane.

The identification of the distribution state of these crystal planes and crystal orientations is performed by using a TEM (Transmission Electron Microscop).
y) electron beam analysis, SEM (Scanning Electron M
icroscopy) -ECP (Electron Channeling Pattern)
Or SEM-EBSP (Electron Back Scattering)
Pattern)). In addition, a wide range of observations can be made by combining a macro structure and a micro structure obtained by polarization observation with an optical microscope with the above-described method, and by specifying the crystal plane of each crystal grain structure by the above method, a wide range of crystal orientation distribution can be investigated. Although the crystal planes cannot be specified by polarization observation with an optical microscope, the same crystal planes can be seen with the same contrast, which is an effective method for observing a macroscopic distribution state.

Next, an aggregate having the same crystal plane will be described. The grain streak is a structure seen as a streak pattern extending almost parallel to the rolling direction as described above. The present inventors have examined the relationship between the microstructure and the presence or absence of streak patterns by polarization observation with an optical microscope, and have found the following. First, in a portion where a streak pattern is conspicuously observed, it was observed that crystal grains having similar contrast extended in the rolling direction. On the other hand, where there is no noticeable streak pattern,
Elongation of the grains having the same contrast in the rolling direction was not clearly observed, and grains having different contrasts were mixed and the crystal faces were dispersed.

Essentially affecting the surface treatment such as etching is the aggregation of the same crystal plane. Therefore,
The cause of the appearance of these streaks is determined by the above method, for example, SEM-
When the crystal plane observation is performed in detail by EBSP, the existing crystal planes are (100) plane, (011) plane, (11) plane.
The 2) plane or the (123) plane was found to be the majority.

When the crystal plane analysis is performed by such a method, not only strictly the same crystal plane but also strictly
It can be seen that some other crystal planes are also mixed. However, among these aggregates, it was found that the specific aggregate as described above caused surface appearance defects such as grain streaks.

When only one kind of crystal plane is formed on the surface of the aluminum alloy plate, for example, when the single plate has a single crystal plane like a single crystal, the etching occurs uniformly, so that uneven etching and grain streaks occur. Does not occur. That is, phenomena such as uneven etching and grain streaks occur when two or more types of crystal orientations are mixed. However, pure aluminum alloy sheets used for construction and daily necessities are also required to have strength and formability as their properties. Therefore, they generally have a polycrystalline structure or a rolled structure. Such a crystal plane exists.

The aluminum alloy targeted in the present invention is:
Al purity is 99. as in JIS-1100, 1200, etc.
A pure aluminum-based alloy of 0% or more is assumed and contains small amounts of Fe and Si as basic components.
It is also effective to add an element as shown in (d). The reasons for limiting the range of these elements are as follows.

(A) Ti: 0.1% by mass or less (0% by mass)
And / or B: 0.1% by mass or less (0%
(B) Cu: 0.5% by mass or less (excluding 0% by mass)
And / or Mn: 0.5% by mass or less (not including 0% by mass) (c) Mg: 0.5% by mass or less (excluding 0% by mass) (d) Cr: 0.3% by mass or less ( (Not including 0% by mass)
And / or Zr: 0.3% by mass or less (excluding 0% by mass)

Fe: 0.8% by mass or less (including 0% by mass
And 0.5% by mass or less (including 0% by mass)
Fe ) effectively acts to refine the recrystallized grains generated during annealing of the product, and is effective for improving the formability and preventing the surface roughness. However, if the amount exceeds 0.8% by mass, the effect is lost. The preferable lower limit of the Fe content is 0.003% by mass, and the preferable upper limit is 0.7%.
% By mass.

Si improves the strength of the product and LDR.
This is effective for improving the formability such as (limit aperture value). However, even if it is added in excess of 0.5% by mass, not only improvement in moldability cannot be expected, but also an Al-Fe-Si-based intermetallic compound is generated, and in addition, uneven alumite color tone is likely to be generated. The preferred lower limit of the Si content is 0.003% by mass, and the preferred upper limit is 0.4% by mass.

Ti: 0.1% by mass or less (including 0% by mass
No) and / or B :: 0.1% by mass or less (0% by mass)
%) Ti and B effectively act to refine the cast structure and refine the recrystallized grains of the rolled sheet. However, in both cases, the 0.
If the content exceeds 1% by mass, the above effect is not only saturated, but also a coarse Al-Ti compound is formed, and the compound is distributed in a striped form on the rolled sheet to give a defect to the anodized film. It will also be. In addition, there is a method of adding Ti as a Ti-B composite compound in addition to Ti alone, but even in this case, there is no change in adjusting the content to the above range. Further, the preferable lower limits of Ti and B are each 0.1.
0001% by mass, and the preferred upper limit is 0.0
9% by mass.

Cu: 0.5% by mass or less (including 0% by mass
And / or Mn: 0.5% by mass or less (0% by mass)
%) Cu and Mn exert an effect of stabilizing the drawability and ear ratio and improving the formability. Cu is an element that also contributes to strength improvement. However, if the amount exceeds 0.5% by mass, the effect is saturated. Note that the preferred lower limits of Cu and Mn are each 0.1.
0001% by mass, and the preferable upper limit is 0.4
% By mass.

Mg: 0.5% by mass or less (including 0% by mass
Mg ) is an element that contributes to strength improvement, but its effect is saturated when its amount exceeds 0.5% by mass. The preferred lower limit of Mg is 0.0001% by mass, and the preferred upper limit is 0.4% by mass.

Cr: 0.3% by mass or less (including 0% by mass)
And / or Zr: 0.3% by mass or less (0% by mass)
( Excluding %) Cr and Zr are elements that contribute to stabilization of the crystal grains, but when their amounts exceed 0.3% by mass, the effect is saturated. The preferred lower limits of Cr and Zr are both 0.0001% by mass, and the preferred upper limits are both 0.2% by mass.

In the aluminum alloy plate of the present invention,
If the content is 0.05% by mass or less and 0.15% by mass or less in total as additional elements or unavoidable impurities other than those described above, these elements do not affect the characteristics of the present invention and are added. It does not matter. Such components include Zn, Ni, V, Be, Bi, Sn, Pb, Ga and the like.

Next, a method for manufacturing an aluminum alloy plate satisfying the above requirements will be described. First, the alloy ingot used in the present invention may be one manufactured by a normal DC casting method. This alloy ingot is subjected to a soaking process, but the soaking process may also be performed after the surface grinding and before the hot rolling, or as a homogenizing process before the heating of the hot rolling. You may go. It is to be noted that, if a homogenizing treatment is performed in advance, and then the surface is shaved and reheated, and then hot rolling is performed, the oxide film on the surface of the ingot before rolling is reduced, which is effective in improving the surface quality.

The hot rolling includes hot rough rolling and hot finishing rolling, which must be performed by different rolling mills. That is, the present invention controls the recrystallization during the transition from the start to the end of the rough rolling to the finish rolling, and suppresses the generation of grain streaks and living marks, and for that purpose, hot rough rolling and hot finishing This is because it is convenient to perform rolling by different rolling mills.

In order to obtain the aluminum alloy sheet according to the present invention, the starting temperature of the hot rough rolling is set to 450 ° C. or less, the rolling speed is set to 50 m / min or more according to the starting pass conditions, and the rolling reduction is set to 30 mm or more. Rolling is performed so as to satisfy either one of the pass drafts of 30% or more, and the end temperature is set to 300 to 370 ° C.

By satisfying the above conditions, the occurrence of grain streaks and living marks can be prevented. Further, the effect of improving the pickup level and reducing the variation in product characteristics in the coil can be exhibited. Further, an aluminum alloy sheet having excellent surface properties can be realized in a low-cost step of only annealing-cold rolling and cold rolling in a subsequent step.

In the present invention, the structural factors relating to the surface properties are controlled from the starting conditions in the hot rolling from the starting conditions, and the essential improvement is attempted. The reason why the characteristics are improved by the above hot rough rolling conditions is as follows. Can be considered as follows.

In order to disperse the same crystal orientation, it is necessary to first refine the crystal grain size during rough rolling. In this regard, in the prior art, this was achieved by controlling the temperature and rolling reduction near the final pass, but in the present invention, the crystal orientation state was successfully dispersed by further controlling the starting conditions of rough rolling. . In addition, since the present invention aims to refine the structure from the start of hot rolling, precipitation during hot rolling also occurs uniformly, and a great effect is exhibited in reducing variation in properties within a lot.

If the rolling start temperature exceeds 450 ° C., an aggregate having the same crystal plane is formed in the first half of the rough rolling, which is not preferable. More preferably, the temperature is 430 ° C. or less. That is, the reason why the rolling start temperature is set to 450 ° C. or lower is to generate fine recrystallized grains in the surface layer portion to improve grain streak and pickup level.

The rolling speed from the start of rough rolling is 50 m /
min or more. When the rolling speed is less than 50 m / min, the strain and strain rate introduced to the surface during rolling are reduced, and the recrystallized grain size generated between passes is coarsened.
This will form an element of an aggregate having the same crystal orientation. It is recommended that this rolling speed be more preferably 60 m / min or more.

As the rough rolling conditions, it is necessary to satisfy at least one of a reduction amount of 30 mm or more and a reduction ratio of one pass: 30% or more. These requirements are important from the viewpoint of dispersing the crystal orientation by processing the surface with a large strain or strain rate. These conditions must be satisfied from the start to the end of rolling.
A more preferable range of these conditions is a reduction amount: 40 mm
As described above, the rolling reduction in one pass is 35% or more. The rolling reduction of each rolling pass means the thickness before and after one rolling pass, respectively.
_n , t _{n + 1} , {(t _n −t _{n + 1} ) / t _n } ×
It is represented by 100 (%).

The end temperature of the rough rolling must be 300 to 370 ° C. When the temperature is lower than 300 ° C., fine recrystallized grains are not generated on the surface portion or a partial recrystallized structure is formed, and an aggregate having the same crystal plane is generated. On the other hand, if this temperature exceeds 370 ° C., the same crystal plane grows due to crystal grain growth or grain boundary movement, which is not preferable. A more preferred lower limit of this temperature is 310 ° C, and a more preferred upper limit is 360 ° C. Such temperature control can be achieved by controlling the speed of the final pass or water cooling after the pass.

After hot rolling, there are various types of cold rolled materials and recrystallized and annealed materials in terms of the thickness and strength required for products for each application. In the prior art, a method of avoiding the generation of grain streaks, living marks, and the like as the number of steps is increased, such as performing cold rolling and annealing twice in a subsequent step, has been adopted. If the number of steps increases, the cost increases as the number of steps increases, which is not preferable.

On the other hand, in the present invention, since the structure is fundamentally controlled by adjusting the conditions of the rough hot rolling, the post-process after the hot rolling is performed only by annealing-cold rolling or only cold rolling. Further, it is possible to provide an aluminum alloy sheet having excellent surface properties even in a low-cost process such as finishing rolling.

Regarding the finish rolling end temperature, when the post-process is only cold rolling or when the finished rolled sheet remains, recrystallization of the surface portion after the finish rolling results in more excellent surface properties. It is necessary to set the temperature to cause recrystallization. From such a viewpoint, the finish rolling temperature (winding temperature) needs to be at least 280 ° C. or more, and more preferably 300 ° C. or more. By satisfying these conditions, an aluminum alloy sheet having excellent surface properties can be realized even if the subsequent annealing step is omitted, and it is advantageous in terms of cost.

On the other hand, in the case where an annealing step is required after the finish rolling in relation to the properties such as strength, it is preferable to have a worked structure after the finish rolling. When a partially recrystallized grain or the like is generated, a non-uniform structure is formed at the time of cold rolling or after annealing, which leads to generation of the same crystal orientation group. That is, the finish rolling conditions need to be optimized according to the post-process.

The finished sheet thickness after hot finish rolling is determined by the sheet thickness of the product, but may be any sheet thickness capable of performing the cold rolling conditions of the present invention.
It is usually about 2.5 to 12 mm for about 6 mm.

The annealing conditions after hot rolling are not particularly limited as long as they are temperatures at which complete recrystallization occurs. Excessive annealing is performed on the same crystal surface due to crystal grain growth or grain boundary movement. Will grow and generate aggregates. Usually, if it is a batch type annealing to be gradually heated annealing, it may be about 0.5 to 6 hours at 300 to 450 ° C., or if it is a continuous annealing, it is 0.3 to 430 to 580 ° C.
It may be about 60 seconds. However, batch annealing is preferred from the viewpoint of low cost.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples do not limit the present invention, and any change in the design based on the above and following points is not limited to the present invention. It is within the technical scope of the invention.

[0053]

EXAMPLE 1 An aluminum alloy having a chemical composition shown in Table 1 below was formed by ordinary DC casting to a thickness of 50 mm and a width of 1500 mm.
Was cast.

Next, the alloy ingot is subjected to a homogenization treatment (610 ° C. × 4 hours), and then subjected to face milling or re-homogenization after the face milling, and then subjected to hot rolling. For this purpose, an aluminum alloy plate (coil) was obtained by heating or furnace cooling and changing the hot rolling conditions as shown in Table 2 below. Table 3 also shows the crystal grain size measured by the following method, the size of an aggregate having the same crystal plane, and the like, together with the steps and conditions after hot working.

(Grain size)
mm, mechanically polished, and then electrolytically etched, observed using an optical microscope (using a polarizing plate), and measured for crystal grain size by a line intercept method in a direction perpendicular to the rolling direction.

(Size of Aggregate of Same Crystal Plane) First, the surface of the plate surface subjected to aqua regia etching was observed with an actual microscope.
Mark the areas that appear dark and mark the approximate streaks. Thereafter, to confirm the same crystal plane, the surface of the plate was electrolytically polished, and then the SEM-EPSP method was used. The same crystal planes (100), (011), (112), and (123) planes are each analyzed, the same crystal planes are color-coded, the area ratio per 1 × 1 mm ² is determined by image analysis, and 30% The measurement of 5 to 10 lengths in the rolling direction between the above-described locations was performed, and the average was taken as the size of the aggregate.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

Regarding the characteristics such as grain restalk, living mark, and rough skin, respectively, at the end and the center in the width direction at the front, middle, and rear in the length direction of each obtained coil.
Investigation was conducted by the following method. The results are shown in Table 4 below.

(Characteristic Investigation Method) Grain Stokes were evaluated by the following criteria by visually observing the surface properties after etching the plate with aqua regia. For living marks and rough skin, blank diameter: 61 m
m, punch diameter: After squeezing the cup with 33 mm, the surface properties were visually observed and evaluated according to the following criteria. (1) Grain streak, uneven etching ◎: good, ○: acceptable, △: bad, ×: extremely bad
Strongly generated

[0062]

[Table 4]

Example 2 An aluminum alloy having a chemical composition shown in Table 5 below was ingoted, and then homogenized at 610 ° C. for 4 hours.
Hot rolled to 3.5mm thick plate, 2m after 40% cold rolling
The plate was made m thick. Table 4 also shows the crystal grain size measured in the same manner as described above, the size of the aggregate having the same crystal plane, and the like.

Characteristics such as grain streaks, living marks, and rough skin were examined at the ends and the center in the width direction at the front, middle, and rear of each of the obtained coils in the length direction. The results are shown in Table 6 below.

[0065]

[Table 5]

[0066]

[Table 6]

As is clear from these results, those of the examples satisfying the requirements specified in the present invention are excellent in grain streak and etching characteristics, and do not cause living marks and rough surfaces in drawing, and have good surface properties. It turns out that it is excellent.

[0068]

The present invention is constituted as described above, and has excellent characteristics such as grain streaks, does not cause living marks and rough skin in drawing, and has excellent etching uniformity of the plate. An aluminum alloy for surface treatment with less variation in characteristics in the coil was realized.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C22F 1/00 694 C22F 1/00 694A 694B (72) Inventor Yuichi Seki 1-5-5 Takatsukadai, Nishi-ku, Kobe Co., Ltd. Kobe Steel, Kobe Research Institute

Claims (8)

[Claims] 1. An aluminum alloy plate containing Fe and Si, wherein an average grain size of crystals appearing on the surface of the alloy is 100 μm or less, and a size of an aggregate having the same crystal plane is reduced by rolling. An aluminum alloy plate having excellent surface properties, which is 10 mm or less in a direction. 2. The assembly has a (100) plane, (01)
2. The aluminum alloy plate according to claim 1, wherein the aluminum alloy plate is an aggregate of crystal grains showing any one of the 1) plane, the (112) plane, and the (123) plane on the surface. 3. 3. The content of Fe is 0.8% by mass or less (not including 0% by mass), and the content of Si is 0.5% by mass.
The aluminum alloy plate according to claim 1, wherein the content is the following (not including 0% by mass). 4. As still another element, Ti: 0.1% by mass or less (not including 0% by mass) and / or B: 0.
The aluminum alloy plate according to claim 3, which contains 1% by mass or less (excluding 0% by mass). 5. As still another element, Cu: 0.5% by mass or less (not including 0% by mass) and / or Mn:
The aluminum alloy sheet according to claim 3, wherein the aluminum alloy sheet contains 0.5% by mass or less (excluding 0% by mass). 6. The aluminum alloy sheet according to claim 3, further comprising Mg: 0.5% by mass or less (not including 0% by mass) as another element. 7. As still another element, Cr: 0.3% by mass or less (not including 0% by mass) and / or Zr:
The aluminum alloy sheet according to any one of claims 3 to 6, wherein the aluminum alloy sheet contains 0.3% by mass or less (excluding 0% by mass). 8. In producing the aluminum alloy according to claim 1, after subjecting the ingot to soaking treatment, the rolling start temperature is set to 450 ° C. or lower, and 50 m / min or more from the start pass. An excellent surface texture characterized by performing hot rough rolling at an end temperature of 300 to 370 ° C. while satisfying either a rolling rate of 30 mm or more and a rolling reduction of 30 mm or more or a one-pass rolling reduction of 30% or more. Of manufacturing aluminum alloy sheet.