JP3974270B2 - Aluminum alloy plate with excellent surface properties - Google Patents

Description

【００５８】
【表２】

【００５９】
【表３】

【００６０】
得られた各コイルの長さ方向の前、中、後部での幅方向の端部と中心の夫々について、グレインスリトーク、リビングマーク、肌荒れ等の特性について、下記の方法で調査した。これらの結果を、下記表４に示す。
【００６１】
（特性の調査方法）
グレインストークスについては、板を王水でエッチングした後に目視でその表面性状を観察し、下記の基準で評価した。またリビングマークおよび肌荒れについては、ブランク径：６１ｍｍ、ポンチ径：３３ｍｍでカップを絞った後、目視でその表面性状を観察し、下記の基準で評価した。
(1) グレインストリーク、エッチングむら
◎：良好、 ○：可、 △：悪い、 ×：非常に悪い
(2) リビングマークおよび肌荒れ
◎：発生なし、 ○：軽度に発生、 △：発生、 ×：強く発生
【００６２】
【表４】

【００６３】
実施例２
下記表５に示す化学成分組成のアルミニウム合金を造塊後、６１０℃×４時間の条件で均質化処理を施した後、熱間圧延で３．５ｍｍ厚さの板とし、４０％冷延後２ｍｍ厚さの板材にした。尚表４には、上記と同様にして測定した結晶粒径、および同一結晶面の集合体のサイズ等についても示した。
【００６４】
得られた各コイルの長さ方向の前、中、後部での幅方向の端部と中心の夫々について、グレインストリーク、リビングマーク、肌荒れ等の特性について調査した。これらの結果を、下記表６に示す。
【００６５】
【表５】

【００６６】
【表６】

【００６７】
これらの結果から明らかな様に、本発明で規定する要件を満足する実施例のものは、グレインストリーク、エッチング特性に優れ、絞り加工においてリビングマークや肌荒れ等が生じずに、表面性状に優れていることが分かる。
【００６８】
【発明の効果】
本発明は以上の様に構成されており、グレインストリーク等の特性に優れ、絞り加工においてリビングマークや肌荒れ等が生じることなく、また板のエッチング均一性にも優れ、しかもそれら特性のコイル内でのばらつきが少ない表面処理用アルミニウム合金が実現できた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum alloy sheet for surface treatment used as a material for architectural interior / exterior panels, daily necessities, kitchen utensils, lithographic printing plate supports, etc., in particular anodizing, polishing / grinding, chemical Or it is related with the technique which improves the surface property in the aluminum alloy plate used by performing surface treatments, such as an electrochemical etching process.
[0002]
[Prior art]
JIS-1100, 1200, 1500, etc. are known as industrial purity pure aluminum alloy plates (Al purity of 99.0% or more) used for surface treatment, and surface properties are excellent as characteristics. It is required that Specific criteria for evaluating such surface properties are (1) that the surface quality is excellent enough to prevent defects such as grain streaks on the surface, and (2) the living mark on the surface after processing. And that rough skin does not occur. Here, the grain streak is a streak defect that occurs on the surface when the product is anodized, and the living mark is a striped unevenness that occurs along the rolling direction when the product is drawn. .
[0003]
By the way, as a method for producing such an aluminum alloy sheet, a DC cast (semi-continuous cast) alloy ingot is subjected to a process such as homogenization, hot rolling, cold rolling and annealing, or even hot. In general, it is produced by a process in which intermediate annealing is performed between rolling and cold rolling. In order to satisfy the required characteristics such as (1) and (2) in these processes, various ideas have been made so far.
[0004]
For example, Japanese Patent Application Laid-Open No. 64-31954 discloses that a fibrous structure produced by hot rolling remains as a texture only by annealing, and this causes grain streaks. In the method of causing recrystallization between hot rolling passes and eliminating the fibrous structure, the grain streaks are increased by increasing the rolling temperature and increasing the rolling temperature of each hot rolling pass as much as possible. It is disclosed that the occurrence of the above 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 1 minute or more is performed between passes after the total reduction amount exceeds 50%.
[0005]
JP-A-3-204104, JP-A-5-9675, JP-A-5-9674, JP-A-4-23745, etc. have the same description as the above-mentioned JP-A-64-31954 regarding the cause of grain streak. However, as a means for solving the problem, it is shown that a high cold rolling rate is achieved after hot rolling and that the annealing conditions are devised.
[0006]
On the other hand, for architectural panels and daily necessities, bending, overhanging, and drawing at 90 ° or more are performed, so the aluminum alloy sheets used for these applications have excellent formability and surface quality after processing. In order to improve these characteristics, it is said that it is necessary to refine the crystal grain size of the plate material. Further, the rough skin that occurs during the drawing process is said to occur when the recrystallized grain size of the product is large, and reducing the recrystallized grain size is also useful in preventing the rough skin described above.
[0007]
As a technique made from the viewpoint of improving the surface properties by refining the crystal grain size, for example, the technique of JP-A-5-320839 has also been proposed. In this technique, the chemical component composition is adjusted and the final It is disclosed that crystal grain size reduction is achieved by controlling cold rolling, final annealing conditions, and the like.
[0008]
In addition, in the case of an aluminum alloy that is used by polishing / grinding the surface or being subjected to chemical or electrochemical etching treatment, as in the case of being used as a material for a lithographic printing plate support, etc. There is a problem that uneven etching occurs. 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 a thin aluminum plate is required, for example, when the thickness is 1 mm or less, problems such as insufficient strength and uneven strength occur as the strength of the plate.
[0009]
[Problems to be solved by the invention]
In recent years, with respect to the surface properties of aluminum alloy plates, the required characteristics tend to become increasingly severe. However, with the techniques proposed so far, it is impossible to obtain an aluminum alloy plate that can sufficiently meet such demands, and it is actually desired to establish a technique for further improving the surface properties.
[0010]
The present invention has been made paying attention to the circumstances as described above, and its purpose is to produce a surface texture that does not cause grain streaks, living marks and rough skin, and is excellent in etching uniformity of the plate. It is an object of the present invention to provide an excellent aluminum alloy plate and a useful method for producing such an aluminum alloy plate.
[0011]
[Means for Solving the Problems]
The aluminum alloy plate according to the present invention that has solved the above problems is an aluminum alloy plate containing Fe and Si, and the average grain size of crystals appearing on the surface of the alloy is 100 μm or less, The summary is that the size of the aggregate having the same crystal plane is 10 mm or less in the rolling direction. Further, in this aluminum alloy plate, the aggregate is composed of crystal grains in which any one crystal face of (100) face, (011) face, (112) face, and (123) face appears on the surface. It is preferable that it is the aggregate | assembly of.
[0012]
The aluminum alloy plate which is the subject of the present invention assumes a pure aluminum alloy plate of industrial purity, and contains a small amount of Fe and Si as basic components. The amount is preferably 0.8% by mass or less (not including 0% by mass) and 0.5% by mass or less (not including 0% by mass), respectively. In addition, it is also useful to contain the following components (a) to (d) as necessary, whereby the characteristics of the aluminum alloy plate can be further improved.
[0013]
(A) Ti: 0.1% by mass or less (not including 0% by mass) and / or B: 0.1% by mass or less (not including 0% by mass),
(B) Cu: 0.5% by mass or less (not including 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 (not including 0% by mass)
[0014]
On the other hand, in producing the aluminum alloy of the present invention as described above, after the soaking is performed on the ingot, the rolling start temperature is set to 450 ° C. or less, and the rolling speed is 50 m / min or more from the start pass, and What is necessary is just to perform the hot rough rolling which makes final temperature 300-370 degreeC, satisfy | filling either the amount of rolling reduction 30mm or more or 30% or more of 1-pass rolling reduction rates.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present inventors examined the cause of the insufficient surface quality of the conventional aluminum alloy plate from various angles. As a result, it was ascertained that the fact that the distribution state of the crystal plane was not sufficiently controlled was a cause of the deterioration of the surface properties. In addition, the inventors changed the crystal orientation distribution state in various ways, investigated the relationship with the presence or absence of the occurrence of grain streaks, and studied the generation mechanism. It was also found that the crystal plane was a structure elongated in the rolling direction. Based on these ideas, further investigations were made on specific means for improving surface properties. As a result, the present invention was completed by finding that the above-described object could be achieved with the above-described configuration. did.
[0016]
First, requirements defined in the present invention will be described. In the aluminum alloy plate of the present invention, the average grain size of crystals appearing on the surface needs to be 100 μm or less. When this value exceeds 100 μm, not only the etching surface quality becomes rough, but also the surface becomes rough after molding. The average particle size of the crystal is preferably 80 μm or less.
[0017]
It has also been found that the rough surface after the forming process involves some form of aggregates with the same crystal orientation. In this regard, some of the prior art stipulates that each crystal grain size should be 50 μm or less, but if the aggregate is dispersed, a plate that suppresses rough skin even with a crystal grain size of up to about 100 μm. Can be provided. The “crystal grain size” in the present invention is a value measured by a line intercept method in the direction perpendicular to rolling.
[0018]
In the present invention, the “aggregate size 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 1 × 1 mm ² by observation with a stereomicroscope or a microstructure. When the ratio of the same crystal plane per unit is 30% or less in terms of area ratio, it is regarded as an end of the aggregate, and the distance in the rolling direction therebetween 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 feel an appearance defect such as a streak pattern. The area ratio in the present invention is obtained by analyzing the same crystal plane by the above method, color-coding the same crystal orientation, and image-processing this. The preferable upper limit of the area ratio is 25%.
[0019]
When the aggregate size of the same crystal plane defined as described above is 10 mm or less in the rolling direction, generation of surface streaks, living marks, and the like can be prevented. When the aggregate size is larger than 10 mm, appearance defects such as etching unevenness and streaks occur. The aggregate size is preferably 9 mm or less, more preferably 8 mm or less. Such an aggregate is generated both in the processed structure after rolling and in the partially recrystallized structure and recrystallized structure after annealing.
[0020]
The aluminum alloy plate of the present invention preferably has a structure in which the crystal plane and its texture on the surface are specified. Next, these concepts will be described. In a normal aluminum alloy plate, textures called Cube orientation, Goss orientation, Brass orientation, Copper orientation, and S orientation are formed, and there are crystal planes corresponding to them. Here, how the texture is formed differs depending on the processing method even in the same crystal system, and in the case of a plate material by rolling, it is necessary to express it by a rolling surface and a rolling direction. The rolling surface is represented by {XXXXX}, and the rolling direction is represented by <ΔΔΔ> (◯ and Δ are integers). Based on such an expression method, each direction is expressed as follows.
Cube orientation {001} <100>
Goss orientation {011} <100>
Brass orientation {011} <211>
Copper orientation {112} <111>
S orientation {123} <634>
[0021]
That is, it is considered that the etching rate differs depending on the crystal plane, and that the surface roughness changes as the distribution state in the plate surface changes and the surface properties deteriorate. In the present invention, basically, a deviation in orientation within ± 20 ° from these crystal planes is defined as belonging to the same crystal plane.
[0022]
These crystal planes and crystal orientation distributions are identified by electron beam analysis using TEM (Transmission Electron Microscopy), SEM (Scanning Electron Microscopy) -ECP (Electron Channeling Pattern), or SEM-EBSP (Electron Back Scattering). Pattern) etc. can be investigated. In addition, a wide range of crystal orientation distributions can be investigated by combining a macro structure and a microstructure by polarization observation of an optical microscope with the above method, performing a wide range observation, and specifying a crystal plane by the above method for each crystal grain structure. Although crystal planes cannot be specified by polarization observation with an optical microscope, the same crystal planes can be seen with the same contrast, so this is an effective method for viewing a macroscopic distribution state.
[0023]
Next, an assembly having the same crystal plane will be described. A grain streak is a structure seen as a streak pattern extending substantially parallel to the rolling direction as described above. When the present inventors examined the relationship between the microstructure and the presence or absence of streak patterns by polarization observation with an optical microscope, the following became clear. First, in a portion where a streak pattern appeared remarkably, it was recognized that crystal grains having similar contrast extended in the rolling direction. On the other hand, in the places where the streak pattern does not appear remarkably, the elongation in the rolling direction of grains having the same contrast is not clearly recognized, and grains having different contrasts are mixed, and the crystal plane Was found to be dispersed.
[0024]
Essentially affecting the surface treatment such as etching is caused by an aggregate of the same crystal plane. Therefore, when the crystal plane is observed in detail by the above-mentioned method, for example, SEM-EBSP, as to the cause of the appearance of these streaks, the existing crystal plane is (100) plane, (011) plane, (112) plane or ( 123) The surface was found to be the majority.
[0025]
When crystal plane analysis is performed by such a method, it can be seen that the dark streak texture is an aggregate in which not only the same crystal plane but also several other crystal planes are mixed. . However, among these aggregates, it has been found that the specific aggregates as described above cause poor surface appearance such as grain streaks.
[0026]
When only one type of crystal plane is generated on the surface of the aluminum alloy plate, for example, when the entire plate is a single crystal plane like a single crystal, the etching occurs uniformly, so the phenomenon of uneven etching and grain streak is Does not occur. That is, phenomena such as uneven etching and grain streaks occur when two or more crystal orientations coexist. However, pure aluminum alloy plates used for construction and daily necessities are also required to have strength and formability as their characteristics, and are generally polycrystalline or rolled structures. That crystal plane exists.
[0027]
The aluminum alloy targeted in the present invention is a pure aluminum alloy having an Al purity of 99.0% or more like JIS-1100, 1200, etc., and a small amount of Fe and Si as basic components. Although it is contained, it is also effective to add the following elements (a) to (d) if necessary. The reasons for limiting the ranges of these elements are as follows.
[0028]
(A) Ti: 0.1% by mass or less (not including 0% by mass) and / or B: 0.1% by mass or less (not including 0% by mass),
(B) Cu: 0.5% by mass or less (not including 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 (not including 0% by mass)
[0029]
Fe: 0.8% by mass or less (not including 0% by mass) and Si: 0.5% by mass or less (not including 0% by mass)
Fe effectively works to refine the recrystallized grains generated during product annealing, and is effective in improving formability and preventing rough skin. However, when the amount exceeds 0.8% by mass, the effect is lost. In addition, the minimum with preferable Fe content is 0.003 mass%, and a preferable upper limit is 0.7 mass%.
[0030]
Si is effective in improving the formability of LDR (limit aperture value) and the like in addition to improving product strength. However, even if added in excess of 0.5% by mass, improvement in moldability cannot be expected, and an Al—Fe—Si intermetallic compound is produced, and in addition, unevenness in anodized color tends to occur. In addition, the preferable minimum of Si content is 0.003 mass%, and a preferable upper limit is 0.4 mass%.
[0031]
Ti: 0.1% by mass or less (not including 0% by mass) and / or B :: 0.1 % by mass or less (not including 0% by mass)
Ti and B effectively act to refine the cast structure and recrystallized grains of the rolled plate. However, even if the content exceeds 0.1% by mass, not only the above effect is saturated, but also a coarse Al—Ti compound is formed, and the compound is distributed in a streak pattern on the rolled plate, and anodized. It will also give a defect to the treated film. In addition, there is a method of adding Ti as a Ti-B composite compound as well as Ti alone, but even in this case, there is no change in adjusting to the above range. Moreover, the preferable minimum of Ti and B is 0.0001 mass%, and the preferable upper limit is 0.09 mass%.
[0032]
Cu: 0.5% by mass or less (not including 0% by mass) and / or Mn: 0.5% by mass or less (not including 0% by mass)
Cu and Mn have the effect of stabilizing the drawing processability and the variation in ear ratio and improving the formability. Cu is an element contributing to strength improvement. However, if the amount exceeds 0.5% by mass, the effect is saturated. In addition, the minimum with preferable Cu and Mn is 0.0001 mass% in all, and a preferable upper limit is 0.4 mass% in all.
[0033]
Mg: 0.5% by mass or less (excluding 0% by mass)
Mg is an element that contributes to strength improvement, but its effect is saturated when the amount exceeds 0.5 mass%. In addition, the minimum with preferable Mg is 0.0001 mass%, and a preferable upper limit is 0.4 mass%.
[0034]
Cr: 0.3% by mass or less (not including 0% by mass) and / or Zr: 0.3% by mass or less (not including 0% by mass)
Cr and Zr are elements that contribute to the stabilization of crystal grains, but the effect is saturated when the amount of both exceeds 0.3 mass%. The preferred lower limit for Cr and Zr is 0.0001% by mass, and the preferred upper limit is 0.2% by mass.
[0035]
In the aluminum alloy plate of the present invention, as an additional element other than the above or as an unavoidable impurity, each element is 0.05% by mass or less and 0.15% by mass or less in total. It may be added because it has no effect on. Examples of such components include Zn, Ni, V, Be, Bi, Sn, Pb, and Ga.
[0036]
Next, a method for producing an aluminum alloy plate that satisfies the above requirements will be described. First, the alloy ingot used in the present invention may be manufactured by a normal DC casting method. This alloy ingot is subjected to a soaking treatment, but the soaking treatment may be performed after the face milling and also before the hot rolling, or as a homogenizing treatment before the hot rolling heating. You can go. If the homogenization is performed in advance, then the surface is shaved and reheated and then hot rolled, the oxide film on the surface of the ingot before rolling is reduced, which is effective in improving the surface quality.
[0037]
Although hot rolling consists of hot rough rolling and hot finish rolling, these need to be performed by different rolling mills. In other words, the present invention controls recrystallization from the start to the end of rough rolling during the transition to finish rolling, and suppresses the occurrence of grain streaks and living marks. For this purpose, hot rough rolling and hot finishing are performed. This is because it is convenient to perform rolling with different rolling mills.
[0038]
In order to obtain the aluminum alloy sheet according to the present invention, the start temperature of hot rough rolling is set to 450 ° C. or less, and the rolling speed is set to 30 mm or more with a rolling speed of 50 m / min or more from the start pass condition, or the reduction rate of 1 pass The rolling is performed to satisfy either of 30% or more, and the end temperature is set to 300 to 370 ° C.
[0039]
By satisfying the above conditions, the occurrence of grain streaks, living marks, etc. can be prevented. In addition, the pickup level can be improved and the variation in the product characteristics in the coil can be reduced. Furthermore, an aluminum alloy plate having excellent surface properties can be realized in a low-cost process of annealing-cold rolling and cold rolling only in the subsequent process.
[0040]
In the present invention, the structure factor related to the surface property is controlled from the starting conditions for hot rolling, and an essential improvement is attempted. The reason why the characteristics are improved by the hot rough rolling conditions is as follows. You can think like
[0041]
In order to disperse the same crystal orientation, it is first necessary to refine the crystal grain size during rough rolling. In this regard, in the prior art, it was achieved by controlling the temperature and rolling reduction in the vicinity of the final pass, but in the present invention, the crystal orientation state was successfully dispersed by controlling from the rough rolling start condition. . In addition, since the present invention is intended to refine the structure from the start of hot rolling, precipitation during hot rolling occurs uniformly and has a great effect on reducing variation in characteristics within a lot.
[0042]
When rolling start temperature exceeds 450 degreeC, the aggregate | assembly of the same crystal plane is produced | generated in the first half of rough rolling, and it is unpreferable. More preferably, it is good to set it as 430 degrees C or less. That is, the rolling start temperature is set to 450 ° C. or less in order to generate fine recrystallized grains in the surface layer portion and improve the grain streak and the pickup level.
[0043]
The rolling speed from the start of rough rolling needs to be 50 m / min or more. When the rolling speed is less than 50 m / min, the strain and strain rate introduced into the surface portion during rolling are reduced, the recrystallized grain size generated between passes is coarsened, and the origin of the aggregate having the same crystal orientation is formed. It will end up. It is recommended that the rolling speed is more preferably 60 m / min or more.
[0044]
As rough rolling conditions, it is necessary to satisfy at least one of the reduction amount: 30 mm or more or the reduction ratio of one pass: 30% or more. These requirements are important from the viewpoint of dispersing the crystal orientation by processing the surface portion with a large strain or strain rate. These conditions need to be satisfied from the start to the end of rolling. A more preferable range of these conditions is a reduction amount of 40 mm or more and a one-pass reduction ratio of 35% or more. The rolling reduction ratio of each rolling pass is {(t _n −t _{n + 1} ) / t _n } × 100 (%, _{where the} thicknesses before and after one rolling pass are t _n and t _{n + 1} , _respectively . ).
[0045]
The end temperature of the rough rolling needs to be 300 to 370 ° C. When this temperature is less than 300 ° C., fine recrystallized grains are not generated on the surface portion or a partial recrystallized structure is formed, and aggregates of the same crystal plane are generated. On the other hand, when the temperature exceeds 370 ° C., the same crystal plane grows due to crystal grain growth, grain boundary movement, and the like, 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 the speed of the final pass and the water cooling control after the pass.
[0046]
After hot rolling, in view of the plate thickness and strength required for the product for each application, there are various materials such as a cold rolled material and a recrystallized annealing material. In the prior art, a method of avoiding the occurrence of grain streaks, living marks, etc. as the number of processes is increased, such as performing the cold rolling / annealing process twice in the subsequent process, but these methods are used. The surface quality is certainly good, but if the number of processes is increased, the cost increases as the number of processes increases.
[0047]
On the other hand, in the present invention, since the structure is fundamentally controlled by making the hot rough rolling conditions appropriate, the subsequent process after hot rolling is annealing-cold rolling, or only cold rolling, Even in a low-cost process such as finish rolling, it is possible to provide an aluminum alloy plate with excellent surface properties.
[0048]
Regarding the finish rolling end temperature, if the subsequent process is only cold rolling, or if it is a finished rolled sheet, it is better to recrystallize the surface part after finishing rolling, so recrystallization The temperature must be raised. From such a viewpoint, the finish rolling temperature (winding temperature) needs to be at least 280 ° C. or higher, but more preferably 300 ° C. or higher. By satisfying these conditions, an aluminum alloy plate having excellent surface properties can be realized even if the subsequent annealing step is omitted, and it is advantageous in terms of cost.
[0049]
On the other hand, in relation to properties such as strength, when an annealing process is required after finish rolling, it is preferable to have a processed structure after finish rolling. When partially recrystallized grains or the like are formed, a non-uniform structure is formed during cold rolling or after annealing, leading to the generation of the same crystal orientation group. In other words, the finish rolling conditions need to be optimized according to the subsequent process.
[0050]
The finished plate thickness after hot finish rolling is determined by the plate thickness of the product, but any plate thickness that can implement the cold rolling conditions of the present invention may be used, and the product plate thickness that is usually applied is about 1 to 6 mm. On the other hand, it is usually about 2.5 to 12 mm.
[0051]
Note that the annealing conditions after hot rolling are not limited to those that can cause complete recrystallization, but excessive annealing may cause growth of the same crystal plane due to grain growth or grain boundary movement. It will happen and create an aggregate. Usually, if it is a batch-type annealing which becomes a slow heating annealing, it may be about 0.5 to 6 hours at 300 to 450 ° C, and if it is a continuous annealing, it is 0.3 to 60 at 430 to 580 ° C. It may be about 2 seconds. However, from the viewpoint of low cost, batch annealing is preferable.
[0052]
Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not intended to limit the present invention, and any design changes may be made in accordance with the gist of the present invention. It is included in the scope.
[0053]
【Example】
Example 1
An ingot having a thickness of 50 mm and a width of 1500 mm was cast from an aluminum alloy having the chemical composition shown in Table 1 by ordinary DC casting.
[0054]
Next, the alloy ingot is subjected to a homogenization treatment (610 ° C. × 4 hours), then subjected to a surface homogenization treatment or a surface homogenization again, and then subjected to hot rolling. The 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 the aggregate of the same crystal plane, and the like, along with the steps and conditions after hot.
[0055]
(Crystal grain size)
After mechanically polishing the surface of the plate to about 0.05 to 0.1 mm, it was electrolytically etched, observed using an optical microscope (using a polarizing plate), and crystal grain size particles were measured by a line intercept method in the direction perpendicular to rolling. .
[0056]
(Size of aggregate of the same crystal plane)
First, the surface of the plate that has been subjected to aqua regia etching is observed with a microscope, and the darker areas are marked and the rough lines are marked. Thereafter, the same crystal plane was confirmed by performing SEM-EPSP method after plate surface portion electropolishing. The same crystal planes (100), (011), (112), and (123) planes are analyzed, the same crystal plane is color-coded, and the area ratio per 1 × 1 mm ² is determined by image analysis, and 30% The measurement of the length 5-10 point in the rolling direction between the above-mentioned places was performed, and the average was made into the size of an aggregate.
[0057]
[Table 1]

[0058]
[Table 2]

[0059]
[Table 3]

[0060]
The characteristics such as grain stalk, living mark, and rough skin were investigated by the following method for each of the end and center in the width direction at the front, middle, and rear of the obtained coils. These results are shown in Table 4 below.
[0061]
(Characteristic investigation method)
About grain stokes, the surface property was observed visually after etching a board with aqua regia, and the following reference | standard evaluated. Moreover, about the living mark and rough skin, after squeezing the cup with a blank diameter: 61 mm and a punch diameter: 33 mm, the surface property was visually observed and evaluated according to the following criteria.
(1) Grain streak and etching unevenness ◎: good, ○: acceptable, △: bad, ×: very bad
(2) Living mark and rough skin ◎: No occurrence, ○: Mild occurrence, △: Occurrence, ×: Strong occurrence [0062]
[Table 4]

[0063]
Example 2
After ingot forming aluminum alloy having chemical composition shown in Table 5 below, homogenization treatment was performed under conditions of 610 ° C. × 4 hours, then hot rolled into a 3.5 mm thick plate, after 40% cold rolling The plate was 2 mm thick. Table 4 also shows the crystal grain size measured in the same manner as described above, the size of the aggregate of the same crystal plane, and the like.
[0064]
The characteristics of grain streaks, living marks, rough skin, etc. were investigated for each of the end and center in the width direction at the front, middle, and rear of each coil obtained. These results are shown in Table 6 below.
[0065]
[Table 5]

[0066]
[Table 6]

[0067]
As is clear from these results, the examples satisfying the requirements specified in the present invention are excellent in grain streak and etching characteristics, and have excellent surface properties without causing a living mark or rough skin during drawing. I understand that.
[0068]
【The invention's effect】
The present invention is configured as described above, and is excellent in characteristics such as grain streak, without causing a living mark or rough surface in drawing, and excellent in etching uniformity of the plate, and in the coil having these characteristics. A surface treatment aluminum alloy with little variation in the thickness was realized.

Claims (5)

An aluminum alloy plate containing Fe and Si,
Fe content is 0.8 mass% or less (excluding 0 mass%), Si content is 0.5 mass% or less (excluding 0 mass%), and the balance is Al and inevitable impurities Consists of
The average grain size of the crystals appearing on the surface of the alloy is 100 μm or less, and the size of the aggregate having the same crystal plane is 10 mm or less in the rolling direction. An aluminum alloy plate excellent in surface properties, characterized in that it is an aggregate of crystal grains showing any one of the 011), (112), and (123) planes on the surface.   Further, Ti: 0.1% by mass or less (not including 0% by mass) and / or B: 0.1% by mass or less (not including 0% by mass) are included as other elements. The aluminum alloy plate described in 1.   Furthermore, as other elements, Cu: 0.5% by mass or less (not including 0% by mass) and / or Mn: 0.5% by mass or less (not including 0% by mass) are contained. Or the aluminum alloy plate of 2.   The aluminum alloy plate according to any one of claims 1 to 3, which contains Mg: 0.5% by mass or less (not including 0% by mass) as another element.   Further, as other elements, Cr: 0.3% by mass or less (not including 0% by mass) and / or Zr: 0.3% by mass or less (not including 0% by mass) are contained. The aluminum alloy plate in any one of -4.