JP2011084800A - High purity aluminum rolled sheet and method for producing the rolled sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high purity aluminum rolled sheet having a smooth surface free from defects such as fine cracks as-rolled without applying chemical polishing and electrolytic polishing. <P>SOLUTION: The high purity aluminum rolled sheet has a purity of ≥99.999 mass%. The surface of the rolled sheet is a mirror face not subjected to polishing treatment, the arithmetic average roughness Ra of the surface is ≤0.05 μm, and the crystal grain size of the surface is ≤50 μm. The high purity aluminum rolled sheet can be obtained by performing rolling in such a manner that rolling ratio in cold rough rolling is ≤90%, and, in cold finish rolling, working ratio is 20-80% and at one pass working ratio of 2-15% while retaining the temperature of the high purity aluminum material to 0-50°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-purity aluminum rolled sheet that is useful for applications that require, for example, a mirror surface with few defects such as cracks on the surface.

  For example, as an aluminum rolled plate whose surface is mirror-finished, a glittering aluminum alloy (see Patent Document 1) used for automobile moldings, reflectors, and the like is used. Since smoothness of the surface is required to obtain glitter, the surface of the rolled plate has been used after being subjected to chemical polishing or electrolytic polishing.

  However, chemical polishing and electrolytic polishing consume chemicals and electrolysis power, and therefore have a high environmental load and reduce the productivity of the rolled plate. Therefore, the rolled plate remains a rolled plate that is not subjected to such surface polishing treatment. However, since the compound resulting from the impurities contained in the raw material of the rolled sheet had reduced the smoothness of the surface of the rolled sheet, no glitter was obtained.

  Therefore, the present inventor has examined a rolled plate made of high-purity aluminum with few impurities in order to obtain a rolled plate having a smooth surface without performing surface polishing treatment.

Japanese Patent Laid-Open No. 02-138447

However, with a conventional high-purity aluminum rolled plate, a smooth surface could not be obtained unless surface polishing such as chemical polishing or electropolishing was performed. The reason is that fine cracks occurred on the surface of the high-purity aluminum rolled plate, and such fine cracks are used when the surface of the rolled plate made of high-purity aluminum is used by chemical polishing or electrolytic polishing. The fine cracks were removed.
However, in order to omit the surface polishing step of the rolled plate and improve productivity, there has been a demand for an aluminum rolled plate having a smooth surface with no defects as a rolled plate not subjected to surface polishing treatment. Due to the presence of fine cracks, there is a problem that a smooth surface cannot be obtained even if the surface is specular.

  Then, this invention makes it a subject to provide the high purity aluminum rolled sheet which has a smooth surface without defects, such as a fine crack, with a rolling, without performing chemical polishing or electrolytic polishing.

  The present inventor has intensively studied to solve the above problems. As a result, when high-purity aluminum material is rolled to a mirror surface, fine cracks are generated on the surface of the rolled material in the direction perpendicular to the rolling direction during cold rolling. The generation of this coarse crystal grain is a phenomenon peculiar to high-purity aluminum, and it has been found that a high-purity aluminum rolled sheet having a smooth rolled surface without cracks can be obtained by preventing this, The present invention has been completed.

That is, the present invention has the following configuration.
(1) A high-purity aluminum rolled plate having a purity of 99.999% by mass or more, wherein the surface of the rolled plate is a mirror surface that has not been subjected to polishing treatment, and the arithmetic average roughness Ra of the surface is 0.05 μm or less. A high-purity aluminum rolled sheet having a surface crystal grain size of 50 μm or less.
(2) Production of a high-purity aluminum rolled sheet that is cold-rolled using a smooth roll after cold-rolling a high-purity aluminum material made of high-purity aluminum having a purity of 99.999% by mass or more. The cold rough rolling has a processing rate of 90% or less and a cold finishing rolling processing rate of 20 to 80%, and the cold finishing rolling has a temperature of the high-purity aluminum material of 0 to 0%. The method for producing a high-purity aluminum rolled sheet according to (1), wherein the one-pass processing rate is 2 to 15% while maintaining at 50 ° C.
(3) Production of a high-purity aluminum rolled sheet that is cold-rolled using a smooth roll after cold-rolling a high-purity aluminum material made of high-purity aluminum having a purity of 99.999% by mass or more. In the method, between cold rough rolling and cold finish rolling, intermediate annealing is performed by heating at a surface temperature of 50 to 150 ° C. for 1 to 30 minutes and then allowing to cool in the atmosphere. The processing rate is 20 to 80%, and the one-pass processing rate is 2 to 15% while maintaining the temperature of the high-purity aluminum material at 0 to 50 ° C. (1) A method for producing a high-purity aluminum rolled sheet as described in 1.
(4) The said smooth roll is a manufacturing method of the high purity aluminum rolled sheet as described in said (2) or (3) whose maximum height roughness of the surface is 0.05-3 micrometers.

  ADVANTAGE OF THE INVENTION According to this invention, the surface of a high purity aluminum rolled sheet can be made smooth with the rolled sheet which does not perform a surface polishing process. As a result, it is possible to increase the productivity of low-cost and high-brightness rolled sheets. It is used as a circuit board. In addition, since there is no surface polishing step, it is possible to obtain a rolled sheet having a glittering property in a manufacturing process with low environmental load that does not consume chemicals or electrolytic power.

Sample No. of Example 3 is an SEM (scanning electron microscope) photograph (magnification: 500 times, hereinafter the same) in which the surface of the high-purity aluminum rolled plate according to 3 is enlarged. Sample No. of Example 4 is an SEM photograph in which the surface of a high-purity aluminum rolled sheet according to 4 is enlarged. Sample No. of Example 5 is an SEM photograph in which the surface of a high-purity aluminum rolled sheet according to 5 is enlarged. Sample No. of Example 6 is an SEM photograph in which the surface of a high-purity aluminum rolled plate according to 6 is enlarged.

(High-purity aluminum material)
The high-purity aluminum rolled sheet of the present invention is made of high-purity aluminum having a purity of 99.999% by mass or more. The upper limit of the purity of the high-purity aluminum is not particularly limited, but is usually less than 99.99999% by mass. The purity of such high-purity aluminum may be determined by measuring the Al content, but Fe, Ti, V, Cr, Zr, Si, Cu and Mg (hereinafter collectively referred to as “8 elements”) It is also possible to obtain the content of each element by subtracting the total amount from 100%. That is, generally, elements that can be contained as impurities in high-purity aluminum include Si, Cu, Mg, Fe, Ti, V, Cr, Zr, Li, Be, B, Na, K, Ca, Mn, Ni, Co Zn, Ga, As, Mo, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pt, Hg, Pb, Bi, Th, and U (hereinafter collectively referred to as “35 elements”) In addition, these elements may contain unavoidable impurities other than these 35 elements, but among these, elements other than the above 8 elements are usually very small even if contained. As described above, there is almost no error even if the purity is calculated assuming that the content of elements other than the above eight elements is zero.

  Among impurities that can be contained in the high-purity aluminum, the content of each element of Si, Cu, and Mg is preferably 3 mass ppm or less, respectively, while each of the elements of Fe, Ti, V, Cr, and Zr Each content is preferably 0.1 mass ppm or less. Thereby, defects caused by impurities appearing on the surface of the rolled sheet can be eliminated. The high-purity aluminum preferably has a total content of the 35 elements of 10 mass ppm or less for the same reason.

  Such high-purity aluminum can be obtained by refining ordinary aluminum having a relatively low purity (for example, a grade of about 1 type of JIS-H2102 having a purity of 99.9% by mass). The purification method is not particularly limited, but preferably, the high-purity aluminum is obtained by purification by a three-layer electrolysis method or purification by a segregation method. You may refine | purify both a three-layer electrolytic method and a segregation method. Further, the purification by the three-layer electrolysis method and the purification by the segregation method may be repeated alternately, for example, or one or both of them may be repeated. As specific methods and conditions for the purification by the three-layer electrolysis method and the one-segregation method, the methods and conditions usually used in this field may be adopted as appropriate.

When the high-purity aluminum is rolled, it can be cast in a desired shape and cut. For casting, for example, a normal method may be employed in which high-purity aluminum is heated and melted to form a molten metal, and the obtained high-purity aluminum molten metal is cooled and solidified in a mold, but is not limited thereto. is not. The conditions for casting are not particularly limited, but the heating temperature is usually 700 to 800 ° C., and the heating and melting is usually performed under reduced pressure or under an inert gas (nitrogen gas, argon gas, etc.) atmosphere made of graphite or the like. Performed in a crucible. When performing the heating and melting under reduced pressure is usually ^{1 × 10- 4 ~1 × 10- 2} Pa, preferably in an a ^{1 × 10- 4 ~1 × 10- 3} Pa. 1 × High purity aluminum material performance of even obtained a reduced pressure below 10- ⁴ Pa is no problem, is economically disadvantageous in terms of facilities.

(Rolled plate manufacturing process)
The high-purity aluminum rolled sheet according to the present invention can be obtained by rolling the high-purity aluminum material. The rolling process is performed by a normal method such as a method of repeatedly passing the ingot between these rolls while applying pressure by sandwiching the ingot between a pair of rolls. Until then, rough rolling and finish rolling may be performed. Moreover, what is necessary is just to perform the intermediate annealing mentioned later when material hardens | cures during rough rolling.

(Rough rolling)
Rough rolling may be hot rolling or cold rolling. For example, using a normal alloy steel roll containing component elements such as Cr, Mo, W, V, and Co, a high-purity aluminum material is used between the rolls. It rolls by the usual method of making it pass repeatedly until it becomes the plate | board thickness of. In the case of cold rough rolling, a high-purity aluminum material is rolled at a processing rate of 90% or less, preferably 50 to 90%. When the processing rate is lower than 50%, the productivity is lowered. When the processing rate is higher than 90%, the surface of the high purity aluminum material is easily cured. Other specific methods and conditions (processing temperature, processing time, etc.) at the time of performing rough rolling are not particularly limited, and may be appropriately set within a range not impairing the effects of the present invention.
Here, the processing rate is expressed by the following equation.
Processing rate (%) = 100 × (sheet thickness before rolling−sheet thickness after rolling) / sheet thickness before rolling

(Intermediate annealing)
When the rolling pass is repeated, the surface of the high-purity aluminum material is easily hardened during rolling. When the surface of the high-purity aluminum material is hardened by rough rolling, it is preferable to perform intermediate annealing and soften it to a hardness at which finish rolling can be continued. The condition is preferably that the surface of the high-purity aluminum material is heated at a temperature of 50 to 150 ° C. for 1 to 30 minutes and allowed to cool in the atmosphere. When the temperature of the surface of the high-purity aluminum material is lower than 50 ° C., the surface is difficult to soften. The heating time is usually 1 to 30 minutes, but if it is shorter than 1 minute, the surface of the high-purity aluminum material is difficult to soften, and if it is longer than 30 minutes, the crystal grains on the surface tend to become coarse. The heating time is preferably 5 to 15 minutes. However, the intermediate annealing is not performed depending on the processing rate in the cold rough rolling, for example, even if the processing rate of the cold rough rolling is 90% or more, the surface temperature of the high purity aluminum material If the heating time is within the range of the present invention, cracks do not occur on the surface of the high-purity aluminum material subjected to intermediate annealing.

(Finish rolling)
Subsequent finish rolling uses a smooth roll to roll a high-purity aluminum material at a processing rate of 20 to 80%. If the processing rate is lower than 20%, a smooth surface cannot be obtained. Although the processing rate may be higher than 80%, the number of passes in which rolling is repeated increases and rolling is not efficient. The processing rate is preferably 30 to 70%.
The 1-pass processing rate is preferably 2 to 15%. When the one-pass processing rate is lower than 2%, the productivity is low, and when the processing rate exceeds 15%, the rolling tends to cause coarsening of crystal grains during rolling. More preferably, the one-pass processing rate is 5 to 10%.
Here, the one-pass processing rate is expressed by the following equation.
1 pass processing rate (%) = 100 × (plate thickness before rolling−sheet thickness after 1 pass rolling) / plate thickness before rolling

  The smooth roll used for finish rolling may be a Cr-plated polishing roll. For example, the surface of a high Cr steel roll is polished, then plated with Cr, and then subjected to finish polishing. The roughness of the roll surface is such that the maximum height roughness specified in JIS-B0601: 2001 is 0. A thickness of 0.05 to 3 μm is preferable, and a thickness of about 0.1 μm is preferable. When the maximum height roughness of the roll on the surface is lower than 0.05 μm, the polishing cost is high and not practical. If it is higher than 3 μm, the high-purity aluminum rolled material that has been finish-rolled does not have a mirror surface, and the glitter is reduced.

  The temperature of the high-purity aluminum material during finish rolling is preferably 0 to 50 ° C. The temperature of the high-purity aluminum material may be lower than 0 ° C., but the productivity is lowered below room temperature. If the temperature is higher than 50 ° C., the crystal grains become coarse during rolling due to recrystallization, causing cracks.

(High purity aluminum rolled plate)
The high purity aluminum rolled sheet rolled by the above method is a high purity aluminum rolled sheet having a thickness of 0.1 to 3 mm made of aluminum having a purity of 99.999% by mass or more, and is observed on the surface of the high purity aluminum rolled sheet. It is better that the average crystal grain size of the crystals is as fine as 50 μm or less. If the average crystal grain size is larger than 50 μm, a fine surface due to coarse crystal grains is generated on the surface of the rolled material in the direction perpendicular to the rolling direction during rolling, so that a smooth surface cannot be obtained.

  As for the surface roughness of the high-purity aluminum rolled sheet of the present invention, the arithmetic average roughness Ra specified in JIS-B0601: 2001 is 0.05 μm or less, preferably 0.02 μm or less. When the arithmetic average roughness Ra of the surface is larger than 0.05 μm, the surface of the high-purity aluminum rolled sheet does not become a mirror surface and the glitter is lowered.

  The hardness of the high-purity aluminum rolled sheet of the present invention is preferably 28 Hv or more in terms of Vickers hardness. If the Vickers hardness is lower than 28 Hv, the rolled plate becomes too soft and cracks are generated on the surface of the high-purity aluminum rolled plate.

The surface of the high-purity aluminum rolled sheet of the present invention needs to be a mirror surface for use in reflectors such as general illumination, light-emitting diode illumination, and flat display backlights.
The high-purity aluminum rolled sheet of the present invention can obtain a plate material having a smooth surface without performing a surface polishing treatment such as chemical polishing or electrolytic polishing as in the prior art. Examples of the surface polishing treatment include known electropolishing and chemical polishing methods described in page 180 of “Aluminum Handbook (7th edition)” issued by the Japan Aluminum Association.

  The high-purity aluminum rolled sheet of the present invention as described above can be used as a smooth substrate suitable for forming a reflective material such as general illumination, light-emitting diode illumination, and flat display backlight, and an anodized film having nanopores. Since there is no surface polishing step, productivity is improved, and a material with low environmental load that does not consume chemicals or electrolytic power can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

(Evaluation of performance)
<Measurement of element content>
In the following examples and comparative examples, the content of each element in aluminum (high purity aluminum) was measured by the following method.
The content of each element in aluminum (high purity aluminum) was measured by glow discharge mass spectrometry (using “VG9000” manufactured by Thermo Electron).
<Evaluation of mirror surface>
The mirror surface was visually evaluated as having no roll pattern (O) and having (X).
<Measurement of roughness>
As the surface roughness, arithmetic average roughness Ra defined in JIS-B0601: 2001 was determined.
<Evaluation of crack>
A 500-fold secondary electron beam image was observed on the surface of the rolled plate with a scanning electron microscope, and evaluation was made with no cracks (O) and presence (X).
<Measurement of Vickers hardness>
The Vickers hardness (Hv) was determined with a load of 5 kg with a Vickers hardness tester.
<Measurement of crystal grain size>
The surface of the rolled plate was buffed with emery paper, electropolished, a 5% NaOH aqueous solution was subjected to corrosion treatment at a water temperature of 50 ° C. for 5 minutes, and crystal grains on the surface of the rolled plate were observed with an optical microscope. Also, a straight line (measurement length) is drawn on a photograph taken by enlarging the surface of the rolled plate with an electron microscope (a straight line of 1600 μm at a magnification of 50 times and 400 μm at a magnification of 200 times), and the number of crystal grains in the straight line Counting was performed, and the crystal grain size was determined by the following formula.
Crystal particle size = measured length / number of grains

(Manufacture of high-purity aluminum rolled sheet)
<Raw material: High purity aluminum>
99.999 mass% aluminum obtained by purification by a three-layer electrolytic method (Si = 2 mass ppm, Cu = 2.2 mass ppm, Mg = 0.4 mass ppm, Fe = 1 mass ppm, other than these) The other 31 elements <1 ppm, 35 impurities total <7 mass ppm) were used as the raw material high-purity aluminum.

<High purity aluminum material>
A high-purity aluminum (purity 99.999 mass%) as a raw material is placed in a graphite crucible, and this is vacuum-melted at 780 ° C., and then cast at 150 ° C. (internal dimensions: width 150 mm × length 200 mm × height) The obtained high-purity aluminum material was removed by removing 1 mm of both surfaces to be rolled and cut at a width of 110 mm × a length of 180 mm × a thickness of 20 mm. Hereinafter, sample No. 1 to 5 used this high-purity aluminum material.

(Sample No. 1 to No. 6)
Hereinafter, through the steps (A) to (D), the sample No. 1 to 6 high-purity aluminum rolled sheets were produced. Table 1 shows the rolling conditions in each step for each sample.

(A) Hot Rolling The high-purity aluminum material is a pair of alloy steel hot-rolling rolls (diameter 150 mm, maximum height roughness specified in JIS-B0601: 2001 is 2 μm. ], And rolled at a reduced thickness of 2 mm per pass at 500 ° C., as shown in Table 1, sample No. By hot-rolling the plate thickness from 20 mm to 8 mm for 1-3, a high-purity aluminum material having a width of 110 mm, a length of 450 mm, and a thickness of 8 mm was obtained. Thereafter, the high-purity aluminum material was allowed to cool to room temperature. Sample No. About 4-6, hot rolling was not performed.

(B) Cold rough rolling After the hot rolling, pressure was applied with the same roll as that used in the hot rolling, and rolling was performed at a rate of 10 to 20% at 1 room temperature at room temperature. As shown in Table 1, this was repeatedly rolled until the plate thickness became 1.5 to 3.3 mm to obtain a high-purity aluminum material.
Specifically, the high-purity aluminum material obtained by casting, width 110 mm × length 180 mm × thickness 20 mm, repeatedly rolled to a thickness of 3.3 mm, width 110 mm × length 1090 mm × thickness 3.3 mm, A length of 400 mm was cut off and Sample No. 1 high-purity aluminum material.
Subsequently, the remaining length of 690 mm was rolled to a thickness of 3 mm to obtain a width of 110 mm × a length of 760 mm × a thickness of 3 mm. 2 high-purity aluminum material.
Subsequently, the remaining length of 360 mm was repeatedly rolled to a thickness of 1.5 mm to obtain a width of 110 mm × a length of 720 mm × a thickness of 1.5 mm. 3 high-purity aluminum material.
Also, the high-purity aluminum material obtained by casting, width 110 mm × length 180 mm × thickness 20 mm, was repeatedly rolled to a thickness of 3 mm to obtain a width 110 mm × length 1200 mm × thickness 3 mm, from which a length of 400 mm was cut. Sample No. No. 4 high-purity aluminum material.
Subsequently, the remaining length of 800 mm was rolled to a thickness of 1.5 mm to obtain a width of 110 mm × a length of 1600 mm × a thickness of 1.5 mm. 5 high-purity aluminum material.
High-purity aluminum as a raw material was cast into aluminum with a purity of 99.7%, and the obtained aluminum material, width 110 mm × length 180 mm × thickness 20 mm, was repeatedly rolled to a thickness of 3 mm, width 110 mm × length 1200 mm × thickness 3 mm. 6 aluminum material.
At this time, when the temperature of the sample during rolling reached about 50 ° C. due to heat generated during rolling, the sample was immersed in water at 20 ° C. and cooled, and kept at about 20 ° C. to 50 ° C. After the cold rough rolling, the high-purity aluminum material and the aluminum material were immersed in 20 ° C. water, and the temperature was cooled to 20 to 25 ° C.

(C) Intermediate annealing Cold rough rolled sample No. No. 4 was cut into a width of 110 mm, a length of 200 mm, and a thickness of 3 mm, heated at a temperature of 100 ° C. for 10 minutes, and allowed to cool in the air, thereby performing intermediate annealing.
Cold rough rolled sample No. 5 was cut into a width of 110 mm, a length of 200 mm, and a thickness of 1.5 mm, heated at a temperature of 200 ° C. for 10 minutes, and allowed to cool in the air, thereby performing intermediate annealing (see Table 1).

(D) Cold finish rolling Cold rough rolled sample No. 1 cut into a width of 110 mm and a length of 200 mm. 1 to 3 and sample no. 6 and intermediate annealed sample No. 4 and 5 are sandwiched between a pair of rolling rolls made of a Cr plating alloy (diameter 124 mm, maximum height roughness specified in JIS-B0601: 2001 is 0.1 μm), pressure is applied at room temperature. Rolling was performed at a rate of 5 to 12% in one pass. This is repeatedly rolled at the number of passes shown in Table 1 and at the processing rate shown in the table until the plate thickness reaches 1 to 3 mm, and is rolled with high purity aluminum having a width of 110 mm, a length of 220 to 600 mm, and a thickness of 1 to 3 mm. I got a plate. At this time, the sample temperature during the cold rolling was about 20 to 40 ° C.

  Among the samples obtained as described above, No. The surface of 3 to 6 high-purity aluminum rolled sheets was enlarged and photographed with an electron microscope. The micrographs are shown in FIGS.

  In addition, the obtained sample No. The surface state, the surface crystal grains, and the hardness of the rolled plate were evaluated and measured for 1 to 6 high-purity aluminum rolled plates. The results are shown in Table 2.

Sample No. As shown in Table 1 in rough rolling and finish rolling in the cold rolling process, Samples Nos. 2 and 3 satisfy the ranges according to the present invention in terms of the rolling processing rate and the finishing rolling 1-pass processing rate. As shown in Table 2, the surface state of the high-purity aluminum rolled material obtained in 2 and 3 is a mirror surface while being an unpolished material, and the arithmetic average roughness Ra of the surface is 0.01 μm. The occurrence is gone.
Sample No. 4 shows the rolling processing rate, the surface temperature of the high-purity aluminum material in the intermediate annealing, and the finishing rolling 1-pass processing rate according to the present invention, as shown in Table 1 in the rough rolling, intermediate annealing, and finish rolling in the cold rolling process. In order to satisfy the range, sample no. As shown in Table 2, the surface state of the high-purity aluminum rolled material obtained in No. 4 is a mirror surface while being an unpolished material, the arithmetic average roughness Ra of the surface is 0.01 μm, and cracks are generated. It's gone.
In contrast, sample no. As shown in Table 1, the rolling processing rate satisfies the range according to the present invention as shown in Table 1 in the rough rolling of the cold rolling process. In finish rolling, as shown in Table 1, the finishing rolling 1-pass processing rate, rolling Since the processing rate does not satisfy the range according to the present invention, the sample No. As shown in Table 2, the surface state of the high-purity aluminum rolled material obtained in 1 is not a mirror surface, but has a high surface roughness.
Sample No. As shown in Table 1, in the rough rolling and intermediate annealing of the cold rolling process, 5 is the range in which the rolling processing rate does not satisfy the range according to the present invention, and the surface temperature of the high-purity aluminum material in the intermediate annealing is also according to the present invention. In this case, sample no. As shown in Table 2, the surface state of the high-purity aluminum rolled material obtained in 5 is a mirror surface, but cracks are generated because the crystal grain size is large.
Sample No. In No. 6, since the raw material purity does not satisfy the range according to the present invention, the surface state of the rolled aluminum material is a mirror surface as shown in Table 2, but cracks are generated.

Claims (4)

A high-purity aluminum rolled sheet having a purity of 99.999% by mass or more,
The surface of the rolled plate is a mirror surface that has not been polished,
The arithmetic average roughness Ra of the surface is 0.05 μm or less,
A high-purity aluminum rolled sheet having a surface crystal grain size of 50 μm or less. This is a method for producing a high-purity aluminum rolled sheet in which a high-purity aluminum material made of high-purity aluminum having a purity of 99.999% by mass or more is subjected to cold rough rolling and then cold-finished using a smooth roll. And
The processing rate of cold rough rolling is 90% or less, and the processing rate of cold finish rolling is 20 to 80%,
2. The high purity aluminum rolled sheet according to claim 1, wherein the cold finish rolling is performed at a 1-pass processing rate of 2 to 15% while maintaining a temperature of the high purity aluminum material at 0 to 50 ° C. 3. Manufacturing method. This is a method for producing a high-purity aluminum rolled sheet in which a high-purity aluminum material made of high-purity aluminum having a purity of 99.999% by mass or more is subjected to cold rough rolling and then cold-finished using a smooth roll. And
Between the cold rough rolling and the cold finish rolling, intermediate annealing is performed after heating at a surface temperature of 50 to 150 ° C. for 1 to 30 minutes and then allowing to cool in the atmosphere.
The cold finish rolling has a processing rate of 20 to 80%,
The method for producing a high-purity aluminum rolled sheet according to claim 1, wherein the one-pass processing rate is 2 to 15% while maintaining the temperature of the high-purity aluminum material at 0 to 50 ° C.   The method for producing a high-purity aluminum rolled sheet according to claim 2 or 3, wherein the smooth roll has a maximum surface roughness of 0.05 to 3 µm.