JP2013174018A - Method for producing high-strength aluminum alloy sheet for printing plate of automatic plate making - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high-strength aluminum alloy sheet for a printing plate of automatic plate making, which is a printing plate having excellent uniformity of an electrolytic roughened surface, including a non-whitened back side of the electrolytic roughened surface, and also having excellent strength characteristics.SOLUTION: A method for producing a high-strength aluminum alloy sheet for a printing plate of automatic plate making includes: a first step of producing an ingot by melting and casting an aluminum alloy which includes 0.03-0.15 mass% of Si, 0.25-0.70 mass% of Fe, 0.0005-0.050 mass% of Cu, not less than 0.05 mass% and less than 0.40 mass% of Mg, and 0.005-0.040 mass% of Ti, and controls Zn to the amount of 0.05 mass% or less and Mn to the amount of 0.01 mass% or less, with the balance comprising Al and unavoidable impurities; a second step of performing homogenization and heat treatment of the ingot at 380-600°C; a third step of performing hot rolling of the ingot with a hot rolling finishing temperature of 300-370°C; and a fourth step of producing the aluminum alloy sheet by performing cold rolling without performing intermediate annealing.

Description

  The present invention relates to a method for producing a high-strength aluminum alloy plate for a printing plate used as a support for printing, particularly lithographic printing.

  Generally, an aluminum or aluminum alloy plate is used as a support for offset printing. In order to improve the adhesion of the photosensitive film to the printing plate and the water retention of the non-image area, a rough surface is provided on one surface of the alloy plate. Is being processed. As this roughening treatment method, a mechanical treatment method such as a ball polishing method or a brush polishing method, degreasing with an alkaline aqueous solution such as caustic soda, and then mainly hydrochloric acid, an electrolytic solution mainly containing this, or nitric acid are mainly used. There is an electrolytic surface roughening treatment method that electrochemically roughens the surface of an alloy plate using an electrolytic solution, or a treatment method that combines these mechanical treatment methods and an electrolytic surface roughening treatment method. Then, an alumite film having a thickness of about 1 μm is formed on the roughened surface as described above, and after sealing and drying, a photosensitive film is applied and, if necessary, matte treatment is performed. Cut to make a printing plate. Note that the rough surface plate obtained by the electrolytic surface roughening treatment exhibits high plate-making appropriateness and printing performance, and is suitable for continuous treatment with a coil material.

  In such a printing plate using an aluminum alloy plate as a support, when printing a newspaper or the like with about 100,000 copies, the number of printed sheets is large when the printing plate is mounted on a printing roll (printing machine). If it becomes, it will be easy to produce a crack in aluminum alloy board itself in the bending fixed part of the edge part of a printing plate. Then, starting from this crack, there is also a problem that the printing plate may be broken, that is, the printing plate may cause so-called gripping. Therefore, the development of an aluminum alloy plate for printing plates with higher strength is desired.

  Further, in order to improve the printing durability in the mass printing, a printing plate having an aluminum alloy plate as a support is exposed and developed by a usual method, and then subjected to heat treatment (burning treatment) at a high temperature. The process which thermosets the photosensitive agent of a part is performed. Since the burning treatment is usually performed under conditions of 200 to 290 ° C. × 3 to 10 minutes, the heat resistance (burning property) that does not lower the strength of the aluminum alloy as the support is also demanded by this treatment. .

  As an aluminum alloy plate suitable for such strength characteristics and electrolytic surface-roughening treatment, Patent Document 1 or Patent Document 2 describes the addition of a predetermined amount of Mg, Zn, Mn, Fe, Si, Cu, and Ti. Has been. In these aluminum alloy plates, by adding a predetermined amount of these elements, the uniformity and strength characteristics of the electrolytic roughened surface in the hydrochloric acid or nitric acid electrolytic roughening treatment have been improved.

JP 2004-250794 A (Claim 1, paragraph 0009) JP 2007-70674 A (Claim 3, paragraph 00001)

  However, in the conventional aluminum alloy plate, an intermetallic compound such as Al—Fe—Si, Al—Fe, and Al—Fe—Mn is generated on the surface of the alloy plate during the manufacturing process. Among these intermetallic compounds, if there is an intermetallic compound having a large maximum length, the uniformity of the electrolytic roughened surface tends to decrease. And in the conventional aluminum alloy plate, since the intermetallic compound which exists in the surface has the largest maximum length compared with another metal compound, it is not a level which can be satisfied in the uniformity of an electrolytic roughening surface.

  Furthermore, in recent years, plate setters and the like have appeared due to the spread of CTP (Computer To Plate) plates, and automation has been progressing in the production of printing plates and the like. As a result of these changes in the times, automation of the removal of packed printing plates has advanced. As a result, when the printing plate is removed from the package, the photosensitive film is coated with external light (infrared light or UV sensor light). In order to prevent misexposure of the printing plate, there is a widespread use of the packaging form that the back side of the printing plate (equivalent to a non-coating surface or a non-roughened surface) becomes the front when unpacking. ing. Therefore, it is necessary to make the surface state of the back surface appropriate, which conventionally did not require special management. That is, there is also a problem that the back surface (non-energized surface) of the surface to be roughened is whitened by degreasing or electrolytic surface roughening. From this appearance of the back surface, in the automatic plate making apparatus, the printing plate There has also been a problem that a position trouble cannot be detected by the position sensor, causing a conveyance trouble.

  The present invention has been made in view of such a problem, and is excellent in uniformity of the electrolytic roughened surface, a printing plate in which the back surface of the electrolytic roughened surface is not whitened, and excellent in strength characteristics. It aims at providing the manufacturing method of the high intensity | strength aluminum alloy plate for automatic plate-making printing plates.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have appropriately controlled the electrolytic surface-roughening treatment characteristics, the back surface characteristics and the strength characteristics of the electrolytic surface-roughened surface by controlling the components and production conditions of the aluminum alloy. It came to make the invention which can be made.

  That is, the manufacturing method of the high intensity | strength aluminum alloy plate for automatic plate-making printing plates which concerns on Claim 1 is: Si: 0.03 mass%-0.15 mass%, Fe: 0.25 mass%-0.70 mass% Cu: 0.0005 mass% or more and 0.050 mass% or less, Mg: 0.05 mass% or more and less than 0.40 mass%, Ti: 0.005 mass% or more and 0.040 mass% or less, Zn: 0.05% by mass or less, Mn: 0.01% by mass or less, a first step of producing an ingot by melting and casting an aluminum alloy consisting of Al and inevitable impurities, and the first A second step in which the ingot produced in one step is subjected to a homogenization heat treatment at 380 ° C. to 600 ° C., and the ingot subjected to the homogenization heat treatment in the second step is heated at a rolling end temperature of 300 ° C. to 370 ° C. A third step of hot rolling and the third step The hot-rolled rolled sheet, characterized in that by cold rolling without intermediate annealing and a fourth step of preparing an aluminum alloy plate.

  According to such a procedure, the high-strength aluminum alloy plate for automatic plate-making and printing plate (hereinafter, appropriately referred to as an aluminum alloy plate) contains a predetermined amount of Si, Fe, Cu, Mg, and Ti, and the Mn content is reduced. By controlling the surface of the aluminum alloy plate to a predetermined amount or less, the number density of the intermetallic compound having a large maximum length that makes the electrolytic roughened surface non-uniform can be reduced when the surface of the aluminum alloy plate is electrolytically roughened. The number of intermetallic compounds can be increased. Thereby, formation of initial pits is promoted. Furthermore, the strength of the aluminum alloy plate is improved by the action of Fe, Cu, and Mg. And it can be set as the aluminum alloy plate by which the back surface of an electrolytic roughening surface is not whitened by degreasing and immersion in electrolyte solution by restricting Zn content to below predetermined amount. In the support using the aluminum alloy plate thus obtained, the electrolytic roughened surface and the back surface thereof have appropriate surface characteristics as a printing plate.

  In addition, by using an aluminum alloy having a predetermined composition and performing homogenization heat treatment at a predetermined temperature, hot rolling, and cold rolling, the number density of intermetallic compounds existing on the surface of the aluminum alloy plate is within a predetermined range. Thus, when the surface of the aluminum alloy plate is subjected to an electrolytic surface roughening treatment, formation of initial pits is promoted. In addition, the number density of intermetallic compounds having a large maximum length that makes the electrolytic roughened surface nonuniform is also reduced. Moreover, by optimizing the homogenization treatment temperature, the solid solubility of Fe, Cu, and Mg is increased, and the strength reduction after the burning treatment is suppressed. Furthermore, the intermediate annealing process can be omitted by optimizing the end temperature of the hot rolling.

  The manufacturing method of the high-strength aluminum alloy plate for automatic plate-making printing plates according to claim 2 is Si: 0.03% by mass to 0.15% by mass, Fe: 0.25% by mass to 0.70% by mass, Cu: 0.0005 mass% or more and 0.050 mass% or less, Mg: 0.05 mass% or more and less than 0.40 mass%, Ti: 0.005 mass% or more and 0.040 mass% or less, Zn: A first step in which an ingot is produced by melting and casting an aluminum alloy containing 0.05% by mass or less and Mn: 0.01% by mass or less, the balance being Al and inevitable impurities, and the first step A second step of homogenizing heat treatment at 380 ° C. to 600 ° C. and hot rolling of the ingot homogenized heat treated at the second step at a rolling end temperature of 250 ° C. to 300 ° C. The third step to perform and hot rolling in the third step The rolled sheet was cold-rolled was further intermediate annealing, characterized in that the cold rolling to and a fourth step of preparing an aluminum alloy plate.

  According to such a procedure, the high-strength aluminum alloy plate for automatic plate-making and printing plate (hereinafter, appropriately referred to as an aluminum alloy plate) contains a predetermined amount of Si, Fe, Cu, Mg, and Ti, and the Mn content is reduced. By controlling the surface of the aluminum alloy plate to a predetermined amount or less, the number density of the intermetallic compound having a large maximum length that makes the electrolytic roughened surface non-uniform can be reduced when the surface of the aluminum alloy plate is electrolytically roughened. The number of intermetallic compounds can be increased. Thereby, formation of initial pits is promoted. Furthermore, the strength of the aluminum alloy plate is improved by the action of Fe, Cu, and Mg. And it can be set as the aluminum alloy plate by which the back surface of an electrolytic roughening surface is not whitened by degreasing and immersion in electrolyte solution by restricting Zn content to below predetermined amount. In the support using the aluminum alloy plate thus obtained, the electrolytic roughened surface and the back surface thereof have appropriate surface characteristics as a printing plate.

  In addition, by using an aluminum alloy having a predetermined composition and performing homogenization heat treatment at a predetermined temperature, hot rolling, and cold rolling, the number density of intermetallic compounds existing on the surface of the aluminum alloy plate is within a predetermined range. Thus, when the surface of the aluminum alloy plate is subjected to an electrolytic surface roughening treatment, formation of initial pits is promoted. In addition, the number density of intermetallic compounds having a large maximum length that makes the electrolytic roughened surface nonuniform is also reduced. Moreover, by optimizing the homogenization treatment temperature and performing the intermediate annealing, the solid solubility of Fe, Cu, and Mg increases, and the strength reduction after the burning treatment is suppressed.

  Moreover, the manufacturing method of the high intensity | strength aluminum alloy plate for automatic plate-making printing plates concerning Claim 3 WHEREIN: The said aluminum alloy contains Ni: 0.20 mass% or less further, It concerns on Claim 4. The method for producing a high-strength aluminum alloy plate for automatic plate-making printing plates is characterized in that the Ni content is 0.005 mass% or more and 0.20 mass% or less.

  According to such a procedure, an Al—Fe—Ni intermetallic compound having a higher potential than the Al—Fe based compound is formed on the surface of the aluminum alloy plate, and aluminum is subjected to the electrolytic surface roughening treatment. Formation of initial pits on the surface of the alloy plate is promoted. Therefore, in the support using the aluminum alloy plate obtained in this way, the electrolytic roughened surface and the back surface thereof have more appropriate surface characteristics as a printing plate.

  According to the method for producing a high-strength aluminum alloy plate for automatic plate-making printing plate according to the present invention, the electrolytic roughened surface has excellent uniformity, and the back surface (non-energized surface) of the electrolytic roughened surface is not whitened. An aluminum alloy plate having excellent strength characteristics is produced.

(1) Aluminum alloy plate First, the aluminum alloy plate according to the present invention will be described.
The aluminum alloy plate according to the present invention contains a predetermined amount of Si, Fe, Cu, Mg and Ti, restricts Zn and Mn to a predetermined amount or less, and the balance is made of Al and inevitable impurities. In addition, you may contain predetermined amount Ni as needed. The reason for limiting the numerical range of each chemical component will be described below.

(Si: 0.03 mass% or more and 0.15 mass% or less)
Si precipitates an Al—Fe—Si intermetallic compound on the surface of the aluminum alloy plate, and promotes the formation of initial pits on the surface of the aluminum alloy plate during the electrolytic surface roughening treatment. As a result, the uniformity of the electrolytically roughened surface (hereinafter referred to as “roughened surface”) of the aluminum alloy plate is improved. When the Si content is less than 0.03% by mass, the number density of intermetallic compounds on the surface of the aluminum alloy plate is small, so that the formation of initial pits is insufficient and the uniformity of the rough surface is poor. On the other hand, when the Si content exceeds 0.15% by mass, the number density of intermetallic compounds on the surface of the aluminum alloy plate increases so that the uniformity of the rough surface is inferior. Therefore, Si content shall be 0.03 mass% or more and 0.15 mass% or less.

(Fe: 0.25 mass% to 0.70 mass%)
Fe is an important element for improving the strength of the aluminum alloy sheet. Further, Fe precipitates Al—Fe—Si intermetallic compounds and the like on the surface of the aluminum alloy plate, and promotes the formation of initial pits on the surface of the aluminum alloy plate during the electrolytic surface roughening treatment. As a result, the uniformity of the rough surface of the aluminum alloy plate is improved. When the Fe content is less than 0.25% by mass, the strength of the aluminum alloy plate is lowered, the tensile strength and the bending fatigue strength are lowered, and when the plate is used as a support for a printing plate, the cutting occurs. Furthermore, since the number density of the intermetallic compound on the surface of the aluminum alloy plate is small, the formation of initial pits is insufficient and the uniformity of the rough surface is poor. Moreover, in the range of 0.25 mass% or more and 0.40 mass% or less, the uniformity of the rough surface is good in the electrolytic surface roughening treatment with hydrochloric acid, but the uniformity is slightly inferior in the electrolytic surface roughening treatment with nitric acid. However, when it exceeds 0.40 mass% and is 0.70 mass% or less, the uniformity of the rough surface is good even with the roughening treatment with nitric acid. On the other hand, if the Fe content exceeds 0.70% by mass, the number density of intermetallic compounds on the surface of the aluminum alloy plate is excessively increased, and coarse intermetallic compounds are formed on the surface of the aluminum alloy plate, resulting in roughening. The surface uniformity is poor. Therefore, Fe content shall be 0.25 mass% or more and 0.70 mass% or less. The Fe content is preferably more than 0.40% by mass and 0.70% by mass or less in order to further improve the strength and uniformity of the rough surface.

(Cu: 0.0005 mass% or more and 0.050 mass% or less)
Cu exists in a solid solution state in aluminum, and has an effect of improving the strength of the aluminum matrix and adjusting the potential of the aluminum matrix and the intermetallic compound. When the Cu content is less than 0.0005% by mass, the formation of initial pits is insufficient during the electrolytic surface roughening of the aluminum alloy plate, and the uniformity of the rough surface is poor. On the other hand, when Cu content exceeds 0.050 mass%, coarse pits increase and the uniformity of the rough surface is inferior. Therefore, Cu content shall be 0.0005 mass% or more and 0.050 mass% or less.

(Mg: 0.05 mass% or more and less than 0.40 mass%)
Mg exists in a solid solution state in aluminum and is an important element for improving the strength of the aluminum matrix. When the Mg content is less than 0.05% by mass, the strength of the aluminum alloy sheet is lowered, and the tensile strength, bending fatigue strength and strength after the burning treatment are reduced, and the plate is completely cut out when used as a printing plate support. Will occur. On the other hand, when the Mg content is 0.40% by mass or more, coarse pits increase and the uniformity of the rough surface is poor. Further, a coarse intermetallic compound is formed on the surface of the aluminum alloy plate, and the uniformity of the rough surface is poor. Therefore, Mg content shall be 0.05 mass% or more and less than 0.40 mass%.

(Ti: 0.005 mass% or more and 0.040 mass% or less)
Ti has a great influence on the electrolytic surface roughening characteristics and the structure of the aluminum alloy ingot. When the Ti content is less than 0.005% by mass, the electrolytic surface-roughening pits are not uniform, and the crystal grains of the ingot are not refined and become a coarse crystal grain structure. A strip-shaped streak along the rolling direction is generated, and the strip-shaped streak remains even after the electrolytic surface roughening treatment. On the other hand, when the Ti content exceeds 0.040% by mass, the effect of refining the crystal grains of the aluminum alloy ingot is saturated, and the coarse Al ₃ Ti compound is increased, thereby reducing the uniformity of the electrolytic rough surface. . Therefore, Ti content shall be 0.005 mass% or more and 0.040 mass% or less.

(Zn: 0.05% by mass or less)
Zn exists in a solid solution state in aluminum and has an action of adjusting the potential of the aluminum matrix and the intermetallic compound. However, when the Zn content exceeds 0.05% by mass, the potential of the aluminum matrix is reduced with respect to the Al-Fe-based and Al-Fe-Mn-based intermetallic compounds. Al elution from the aluminum matrix occurs by immersion in the electrolyte in the state. Thereby, the back surface of the electrolytic roughened surface is whitened. For this reason, when the printing plate is automatically conveyed to the automatic plate making processing apparatus, the printing plate position cannot be detected by the sensor, causing a conveyance trouble. This backside whitening phenomenon is particularly likely to occur during electrolytic surface roughening with hydrochloric acid. Therefore, Zn content shall be 0.05 mass% or less. The Zn content is preferably less than 0.02% by mass in order to prevent further whitening of the back surface of the electrolytic roughened surface, and further to prevent whitening of the back surface of the electrolytic roughened surface. Is preferably as small as possible, and is preferably less than 0.003% by mass.

(Mn: 0.01% by mass or less)
Mn is formed in the form of so-called precipitates during the homogenization heat treatment in addition to the so-called crystallization formed during the production of the ingot during the production process of the aluminum alloy sheet. When Mn is contained in excess of a predetermined amount, an Al—Fe—Mn based coarse intermetallic compound is generated. As a result, the rough surface of the aluminum alloy plate becomes non-uniform. Since the Al—Fe—Mn intermetallic compound dissolves in the aluminum alloy when the Mn content is 0.01% by mass or less, coarse intermetallic compounds on the surface of the aluminum alloy plate can be reduced. A uniform rough surface can be obtained. On the other hand, if the Mn content exceeds 0.01% by mass, a coarse intermetallic compound is formed on the surface of the aluminum alloy plate, and the uniformity of the rough surface is poor. Therefore, the Mn content is 0.01% by mass or less.

(Ni: 0.20 mass% or less)
Ni is an element that improves the chemical solubility of the material and improves the etching properties during electrolytic surface roughening. Ni forms an Al—Fe—Ni intermetallic compound on the surface of the aluminum alloy plate. Since this compound has a higher potential than Al-Fe-based compounds, it promotes the formation of initial pits on the surface of the aluminum alloy plate during the electrolytic surface roughening treatment, and a uniform and fine rough surface is obtained in a short time. It becomes possible. However, if the Ni content exceeds 0.20% by mass, a coarse intermetallic compound is formed, and the uniformity of the rough surface is poor. Ni may not be added. However, when 0.005% by mass or more is added, the effect of improving the uniformity of the rough surface is more likely to be exhibited, so 0.005% by mass or more is preferably added. Ni also increases the chemical solubility like Zn, but the aluminum matrix itself does not elute and the back surface of the electrolytically roughened surface does not become white. Therefore, when Ni is added, the Ni content is 0.20 mass% or less, preferably 0.005 mass% or more and 0.20 mass% or less.
Thus, in the present invention, by adding Ni to the aluminum alloy plate, the uniformity of the rough surface can be further improved and the surface property of the aluminum alloy plate can be made better.

(Balance: Al and inevitable impurities)
If the inevitable impurities are inevitable impurities contained in a commercially available aluminum ingot, the object of the present invention is not impaired. Moreover, it is preferable that aluminum purity is 99.0 mass% or more. If the purity is 99.0% by mass or more, the formation of coarse intermetallic compounds is further suppressed, and the rough surface tends to be uniform.

(2) Manufacturing method of aluminum alloy plate Next, the manufacturing method of the aluminum alloy plate which concerns on this invention is demonstrated.
As a manufacturing method of an aluminum alloy plate, there are a first manufacturing method and a second manufacturing method. In the first manufacturing method, intermediate annealing is not performed during the cold rolling, whereas in the second manufacturing method, a cold is performed. Intermediate annealing is performed during rolling. In the 2nd manufacturing method, since intermediate annealing is performed, the end temperature in hot rolling can be made lower than the end temperature in the 1st manufacturing method.

[First production method]
A first method for producing an aluminum alloy plate according to the present invention includes a first step of producing an ingot, a second step of homogenizing heat treatment of the ingot, and a first step of hot rolling the ingot subjected to the homogenization heat treatment. It comprises 3 processes and the 4th process of cold-rolling the hot-rolled rolled sheet.
Hereinafter, each step will be described.

(First step)
The first step is to melt and cast an aluminum alloy in which the content of chemical components (Si, Fe, Cu, Mg, Ti, Zn and Mn, and Ni in the case of containing Ni) is limited to the predetermined range. This is a process for producing an ingot. A conventionally known method is used as the melting and casting method.

(Second step)
The second step is a step of subjecting the ingot produced in the first step to a homogenization heat treatment at 380 ° C. or more and 600 ° C. or less. By this homogenization heat treatment and hot rolling and cold rolling described later, the number density of intermetallic compounds existing on the surface of the aluminum alloy plate can be set within a predetermined range. As a homogenization heat treatment method, a conventionally known method is used. Hereinafter, the reason for limiting the numerical value of the homogenization heat treatment temperature will be described.

(Homogenization heat treatment temperature: 380 to 600 ° C)
When the homogenization heat treatment temperature is less than 380 ° C., in addition to insufficient homogenization heat treatment, the amount of precipitation of intermetallic compounds is small, and the size of intermetallic compounds existing on the surface of the aluminum alloy plate is small. Therefore, the formation of initial pits is not promoted in the roughening treatment, resulting in insufficient roughening and poor uniformity of the rough surface. On the other hand, when the homogenization heat treatment temperature exceeds 600 ° C., the intermetallic compound is dissolved, and the number density of the intermetallic compound existing on the surface of the aluminum alloy plate decreases, so that the diameter of each pit increases and the rough surface The uniformity of is poor. Therefore, the homogenization heat treatment temperature is set to 380 ° C. or more and 600 ° C. or less.
In addition, although the intensity | strength after a burning process becomes higher in the high temperature side and low temperature side rather than an appropriate temperature range, in this case, since it remove | deviates from a temperature range, the uniformity of a rough surface will be inferior. Therefore, by optimizing the homogenization heat treatment temperature, the solid surface of the rough surface is not inferior, and the solid solubility of Fe, Cu, and Mg is increased, thereby suppressing the strength reduction after the burning treatment.

(Third step)
The third step is a step of hot rolling the ingot subjected to the homogenization heat treatment in the second step at a rolling end temperature of 300 ° C. or higher and 370 ° C. or lower. In addition, about a hot rolling method, a conventionally well-known method is used. Moreover, you may repeat hot rolling in multiple times as needed. Hereinafter, numerical limitation of the rolling end temperature of hot rolling will be described.

(Hot rolling finish temperature: 300 ° C or higher and 370 ° C or lower)
When the hot rolling end temperature is less than 300 ° C., dynamic recrystallization in the rolled sheet is insufficient, the crystal structure of the rolled sheet becomes uneven, and the uniformity of the rough surface is inferior. In addition, since the number density of intermetallic compounds existing on the surface of the aluminum alloy plate is insufficient, the formation of initial pits is not promoted, and the uniformity of the rough surface is poor. On the other hand, if the hot rolling end temperature exceeds 370 ° C., crystal grains grow excessively between the passes of hot rolling, and the uniformity of the rough surface is poor. In addition, since the intermetallic compound is dissolved and the number density of the intermetallic compound existing on the surface of the aluminum alloy plate is reduced, the formation of initial pits is not promoted, and the uniformity of the rough surface is poor. In addition, it is not necessary to perform rough annealing immediately after hot rolling by setting the hot rolling end temperature in the above range, and intermediate annealing in the middle of cold rolling can be omitted.
Therefore, when the intermediate annealing in the middle of the cold rolling process after the hot rolling process is omitted, the hot rolling end temperature is set to 300 ° C. or more and 370 ° C. or less.

(4th process)
The fourth step is a step for producing an aluminum alloy plate by cold rolling the rolled plate hot-rolled in the third step without performing intermediate annealing. In addition, about a cold rolling method, a conventionally well-known method is used. Here, the cold rolling rate is preferably 60 to 95%. Moreover, you may repeat cold rolling in multiple times as needed.

[Second production method]
The second method for producing an aluminum alloy sheet according to the present invention includes a first step of producing an ingot, a second step of homogenizing heat treatment of the ingot, and a second step of hot rolling the ingot subjected to the homogenization heat treatment. It is comprised by including the 3rd process and the 4th process which cold-rolls the hot-rolled hot-rolled board, and also intermediate-annealing and cold-rolling.
Hereinafter, each step will be described.

  Since the first step and the second step are the same as those in the first manufacturing method, description thereof is omitted here.

(Third step)
The third step is a step of hot rolling the ingot subjected to the homogenization heat treatment in the second step at a rolling end temperature of 250 ° C. or higher and 300 ° C. or lower. In the second manufacturing method, since the intermediate annealing is performed in the middle of cold rolling, the rolling end temperature can be set to a temperature lower than the end temperature in the first manufacturing method. In addition, it is the same as that of the 3rd process of the said 1st manufacturing method except rolling end temperature. Hereinafter, numerical limitation of the rolling end temperature of hot rolling will be described.

(Hot rolling finish temperature: 250 ° C or higher and 300 ° C or lower)
When the hot rolling finish temperature is less than 250 ° C., dynamic recrystallization in the rolled sheet is insufficient, the crystal structure of the rolled sheet becomes non-uniform, and the uniformity of the rough surface is inferior. In addition, since the number density of intermetallic compounds existing on the surface of the aluminum alloy plate is insufficient, the formation of initial pits is not promoted, and the uniformity of the rough surface is poor. On the other hand, when the hot rolling finish temperature exceeds 300 ° C., when intermediate annealing is performed after cold rolling is performed on the obtained hot rolled sheet, accumulation of strain energy is insufficient and recrystallization caused by the intermediate annealing is performed. Since the grains cannot be made fine, the uniformity of the rough surface is inferior.
Therefore, when intermediate annealing is performed in the middle of the cold rolling process after the hot rolling process, the hot rolling end temperature is set to 250 ° C. or more and 300 ° C. or less.

(4th process)
The fourth step is a step of cold-rolling the rolled plate hot-rolled in the third step and further intermediate annealing and cold rolling to produce an aluminum alloy plate. The intermediate annealing may be performed under conventionally known conditions. For example, it is preferable that batch annealing is performed at 400 to 500 ° C. for 1 to 10 hours, and continuous annealing is performed at 400 to 550 ° C. for 0 to 30 seconds. In addition, since it is the same as that of the 4th process of the said 1st manufacturing method except performing intermediate annealing in the middle of cold rolling, description is abbreviate | omitted here.

  The production method of the present invention is as described above, but in performing the first production method and the second production method, within a range that does not adversely affect each step, Other processes such as a chamfering process for chamfering the ingot, an unnecessary object removing process for removing unnecessary substances such as dust, and a distortion correcting process process for correcting distortion of the plate may be included.

[First embodiment]
Examples (Examples 1 to 13) of the aluminum alloy sheet according to the present invention will be specifically described in comparison with comparative examples (Comparative Examples 1 to 14).

<Examples 1-13, Comparative Examples 1-14>
In the first example, an aluminum alloy plate was produced by the first production method.
An aluminum alloy having the composition shown in Table 1 was melted and cast to produce an ingot, which was chamfered to a thickness of 580 mm. The ingot was homogenized by heat treatment at 480 ° C. × 4 h, hot-rolled at a rolling end temperature of 330 ° C., and wound into a coil with a thickness of 3 mm. The hot-rolled sheet was cold-rolled without being subjected to intermediate annealing to form a rolled sheet having a final product thickness of 0.3 mm, and then subjected to correction with a tension leveler to produce an evaluation coil product. A sheet-like aluminum alloy plate was cut out from the outer periphery of the coil product. In Table 1, those not containing a component are indicated by “−”, and those not satisfying the claims of the present invention are indicated by underlining the numerical values.

Next, the surface of the aluminum alloy plate was subjected to an electrolytic surface roughening treatment under the following conditions.
(Electrolytic surface roughening conditions)
The aluminum alloy plate was degreased with a 5 mass% aqueous sodium hydroxide solution at a temperature of 50 ° C for 30 seconds, and then neutralized and washed with 1 mass% nitric acid at room temperature for 30 seconds. The neutralized and washed aluminum alloy plate is subjected to an electrolytic treatment for 10 seconds in 2% by mass hydrochloric acid under electrolysis conditions of a current density of 120 A / dm ² , a frequency of 50 Hz, and a temperature of 25 ° C., and in 2% by mass nitric acid. An AC electrolytic surface roughening treatment was performed by an electrolytic treatment for 30 seconds under an electrolytic condition of a current density of 50 A / dm ² , a frequency of 50 Hz, and a temperature of 25 ° C. The aluminum alloy plate subjected to electrolytic surface roughening treatment was desmutted with a 5% by mass aqueous sodium hydroxide solution at a temperature of 50 ° C. for 10 seconds, then neutralized with 30% by mass nitric acid at room temperature for 30 seconds, and washed with water. The sample was dried and used as an evaluation sample.

For this evaluation sample, the uniformity of the rough surface was examined. The results are shown in Table 1.
(Evaluation method of uniformity)
The rough surface of the evaluation sample was observed with a SEM at a magnification of 2000 times and photographed. The photographs were placed side by side and three lines with a total length of 100 cm were drawn in parallel, and the uniformity was evaluated by determining the difference in size (maximum length) between the largest pit and the smallest pit below this line. Here, when the difference in the pit size is 1 μm or less, ◎ (very good), and when the pit size difference exceeds 1 μm and 1.5 μm or less, ○ (good), exceeding 1.5 μm Those having a thickness of 2 μm or less were evaluated as Δ (slightly good), and those exceeding 2 μm were evaluated as x (defective). And the evaluation of (double-circle), (circle), (triangle | delta) was set as the pass.

Moreover, the back surface whitening characteristic was investigated about the said aluminum alloy plate. The results are shown in Table 1.
(Evaluation method for backside whitening characteristics)
The aluminum alloy plate was degreased with a 5 mass% aqueous sodium hydroxide solution at a temperature of 50 ° C for 30 seconds, and then neutralized and washed with 1 mass% nitric acid at room temperature for 30 seconds. The neutralized and washed aluminum alloy plate was immersed in 2% by mass hydrochloric acid (temperature 25 ° C.) for 30 seconds, and then desmutted with a 5% by mass aqueous sodium hydroxide solution at a temperature of 50 ° C. for 10 seconds. The lightness L value was measured with the color difference meter about the surface property, and the back surface whitening characteristic (the back surface is not energized) was evaluated. A value of L less than 86.5 is hardly whitened because it is hardly whitened. Therefore, it was set as x (defect).

  Next, the tensile strength and bending fatigue strength of the aluminum alloy plate were measured or calculated by the following method. The results are shown in Table 1.

(Tensile strength evaluation method)
Four pieces each of JIS No. 5 test pieces (JISZ2201) were cut out from the aluminum alloy plate. Two pieces of each of these test pieces (test piece A) and this test piece were inserted into an air furnace set at an atmospheric temperature of 240 ° C., and after the furnace lid was closed, the atmospheric temperature reached 240 ° C. again. A tensile test was performed according to JISZ2241, using two test pieces (test piece B) each taken out from the furnace after the lapse of minutes (for evaluation of tensile strength after burning treatment), and the tensile strength was measured. Here, the average value of each of the two pieces is calculated, and in the test piece A, a specimen having a tensile strength of 180 MPa or more is evaluated as ◯ (good), and a specimen having a tensile strength of less than 180 MPa is evaluated as x (defective). In this case, a sample having a tensile strength of 135 MPa or more was evaluated as “good”, and a sample having a tensile strength of less than 135 MPa was evaluated as “poor”.

(Bending fatigue strength evaluation method)
A test piece (length 10 mm × width 80 mm) was cut out from the aluminum alloy plate. Using this test piece, a plane bending fatigue test according to JISZ2273 was performed with a swing width of 5 mm given in the thickness direction of the test piece. Then, the breaking stress at 10 ⁴ repeated bendings was calculated, and this breaking stress was defined as bending fatigue strength. Here, the one having a breaking stress of 350 MPa or more was evaluated as ◯ (good), and the one less than 350 MPa was evaluated as x (defective). A printing plate using an aluminum alloy plate having good bending fatigue strength has good gripping properties.

  Next, the surface properties of the printing plate using the aluminum alloy plate as a support were examined. The results are shown in Table 1.

(Method for evaluating surface properties of printing plates)
The printing plate was mounted on a general-purpose printing machine, wound up into a roll, and printed to evaluate the surface properties. A dot that does not cause in-plane variation in the halftone dot area, or a print quality that does not deteriorate such that ink remains in an unnecessary part of the ink is marked as ◯ (very good). Slightly occurred, etc., but the print quality did not deteriorate, and there was no problem as a product. △ (good), halftone dot area variation etc. occurred, ink remained in the ink unnecessary part An x (defect) is indicated when the print quality is degraded. And the determination of (circle) and (triangle | delta) was set as the pass.

  As shown in Table 1, in Examples 1 to 13, since the chemical composition satisfies the claims of the present invention (hereinafter referred to as claims), the uniformity of the rough surface, the whitening property of the back surface, and the aluminum alloy plate It was excellent in strength (tensile strength, tensile strength after burning treatment, bending fatigue strength) and surface properties of the printing plate. In Examples 11 and 12, since a preferable amount of Ni was added, the uniformity of the rough surface was particularly excellent.

  In Comparative Example 1, since the Si content was less than the lower limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 2, since the Si content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 3, since the Fe content was less than the lower limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. Further, the strength was insufficient, and the tensile strength and bending fatigue strength were inferior. In Comparative Example 4, since the Fe content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 5, since the Cu content was less than the lower limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 6, since the Cu content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 7, since the Mg content was less than the lower limit value of the claims, the strength was insufficient, and the tensile strength and bending fatigue strength were inferior. In Comparative Example 8, since the Mg content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Examples 9 and 10, since the Mn content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 11, since the Zn content exceeded the upper limit of the claims, the back surface whitening characteristics were inferior. In Comparative Example 12, since the Ni content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 13, since the Ti content was less than the lower limit of the claims, the uniformity of the rough surface was inferior, and the strip-like streaks remained on the surface, so that the surface property of the printing plate was inferior. In Comparative Example 14, since the Ti content exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

[Second Embodiment]
Examples (Examples 14 to 20) of the aluminum alloy plate according to the present invention will be specifically described in comparison with comparative examples (Comparative Examples 15 to 24).

<Examples 14 to 20, Comparative Examples 15 to 24>
An aluminum alloy having an alloy symbol (A or K) shown in Table 1 was melted and cast to produce a 500 mm-thick ingot, which was chamfered to a thickness of 470 mm. The ingot was processed under the manufacturing conditions shown in Table 2, and after cold rolling to obtain a rolled plate having a final product thickness of 0.3 mm, correction was performed using a tension leveler to produce an evaluation coil product. A sheet-like aluminum alloy plate was cut out from the outer periphery of the coil product, and the same items as in the first example were tested and evaluated. The results are shown in Table 2. In Table 2, those not subjected to intermediate annealing are indicated by “−”, and those not satisfying the claims of the present invention are indicated by underlining the numerical values.

  As shown in Table 2, in Examples 14 to 20, since the chemical composition and the production conditions satisfy the claims of the present invention, the uniformity of the rough surface, the whitening property of the back surface, the strength (tensile strength of the aluminum alloy plate) , Tensile strength after burning treatment, bending fatigue strength) and surface properties of the printing plate. In Examples 15 and 20, since a preferable amount of Ni was added, the uniformity of the rough surface was particularly excellent.

  In Comparative Example 15, the homogenization heat treatment temperature was lower than the lower limit value of the claims, and therefore, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 16, since the temperature of the homogenization heat treatment exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 17, the temperature of the homogenization heat treatment exceeded the upper limit value of the claims, so that the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  Comparative Examples 18 and 19 do not perform intermediate annealing. In Comparative Example 18, since the hot rolling end temperature was less than the lower limit value of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 19, the hot rolling end temperature exceeded the upper limit value of the claims, so the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  In Comparative Example 20, the temperature of the homogenizing heat treatment was less than the lower limit value of the claims, so the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 21, since the temperature of the homogenization heat treatment exceeded the upper limit of the claims, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

  Comparative Examples 22 and 23 were subjected to intermediate annealing. In Comparative Example 22, the hot rolling end temperature was less than the lower limit value of the claims, and therefore, the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 23, the hot rolling end temperature exceeded the upper limit value of the claims, so that the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior. In Comparative Example 24, the temperature of the homogenization heat treatment exceeded the upper limit value of the claims, so the uniformity of the rough surface was inferior and the surface property of the printing plate was inferior.

Claims (4)

Si: 0.03% to 0.15% by mass, Fe: 0.25% to 0.70% by mass, Cu: 0.0005% to 0.050% by mass, Mg: 0.05 Containing not less than 0.4% by mass and not more than 0.40% by mass, containing not less than 0.005% by mass and not more than 0.040% by mass, Zn: 0.05% by mass or less, Mn: 0.01% by mass or less, and the balance A first step of melting and casting an aluminum alloy composed of Al and inevitable impurities to produce an ingot;
A second step of homogenizing heat treatment of the ingot produced in the first step at 380 ° C. or more and 600 ° C. or less;
A third step of hot rolling the ingot subjected to the homogenization heat treatment in the second step at a rolling end temperature of 300 ° C. or higher and 370 ° C. or lower;
A high-strength aluminum for automatic plate-making printing plates, comprising a fourth step of producing an aluminum alloy plate by cold-rolling the rolled plate hot-rolled in the third step without performing intermediate annealing Manufacturing method of alloy plate. Si: 0.03% to 0.15% by mass, Fe: 0.25% to 0.70% by mass, Cu: 0.0005% to 0.050% by mass, Mg: 0.05 Containing not less than 0.4% by mass and not more than 0.40% by mass, containing not less than 0.005% by mass and not more than 0.040% by mass, Zn: 0.05% by mass or less, Mn: 0.01% by mass or less, and the balance A first step of melting and casting an aluminum alloy composed of Al and inevitable impurities to produce an ingot;
A second step of homogenizing heat treatment of the ingot produced in the first step at 380 ° C. or more and 600 ° C. or less;
A third step of hot rolling the ingot homogenized in the second step at a rolling end temperature of 250 ° C. or higher and 300 ° C. or lower;
And a fourth step of cold rolling the rolled plate hot-rolled in the third step, further intermediate annealing and cold rolling to produce an aluminum alloy plate, and A method for producing a strength aluminum alloy sheet.   The said aluminum alloy contains Ni: 0.20 mass% or less further, The manufacturing method of the high strength aluminum alloy plate for automatic plate-making printing plates of Claim 1 or Claim 2 characterized by the above-mentioned.   The method for producing a high-strength aluminum alloy plate for automatic plate-making printing plates according to claim 3, wherein the Ni content is 0.005 mass% or more and 0.20 mass% or less.