JP2022035716A - Rolled aluminum alloy material and production method therefor - Google Patents

Abstract

To provide a rolled aluminum alloy material excellent in brilliancy and processability.SOLUTION: A rolled aluminum alloy material in this invention has a chemical composition comprising in mass%, Si of 0.02-0.08%, Fe of 0.02-0.08%, Cu of 0.06-0.15%, Mn of 0.0005-0.01%, Mg of 0.42-0.75%, Ni of 0.001-0.1%, Zn of 0.001-0.1%, Ti of 0.0005-0.04%, Ga of 0.0002-0.01%, B of 0.0002-0.01% and the balance of Al with inevitable impurities. In this material, tensile strength is in a range of 100-180 MPa and conductivity is 50% or more in IACS. Further, the reflectance after chemical polishing treatment at the solution temperature of 90°C for 120 sec. using a chemical polishing solution comprising phosphoric acid of 70 vol%, nitric acid of 5 vol% and the balance of water is 65% or more.SELECTED DRAWING: None

Description

The present invention relates to an aluminum alloy rolled material which is preferably used for cosmetic cases, caps, reflectors for automobiles and interior lighting, decorative objects, etc. by subjecting them to chemical polishing and anodizing after molding, and a method for producing the same. ..

Materials such as JIS A1085 and A1050 are used for cosmetic cases, caps, reflectors for automobiles and interior lighting, decorative items, etc. that require both brilliance and moldability such as deep drawing and spinning. JIS1000 series aluminum materials are often used. Further, for applications where strength is particularly required, 5000 series aluminum materials such as A5052 are often used.

The aluminum material used for such applications is electropolished or chemically polished in an acidic bath containing phosphoric acid as a main component after molding, then anodized, colored as necessary, and then sealed. It is a standard configuration to improve scratch resistance, corrosion resistance, and weather resistance by applying hole treatment.

Especially in recent years, in response to increasing demand for lighting equipment applications equipped with LED elements, and product applications that enhance design and decoration and give products a metallic luster, texture, and luxury, without using electric power. There is an increasing need for materials suitable for chemical polishing that can impart brilliance to complex shapes, minute parts, and the inner surface side.

For such applications, JIS1000-based pure aluminum alloys such as JISA1085 and A1050 mentioned above are excellent in drawability and brilliance after chemical polishing, but because of their low strength, they are used when handled as a product. There is a problem of dents and deformation due to dropping or impact. On the other hand, Al-Mg-based alloys (5000-based alloys) such as JISA5052, which are known as high-strength materials, have high strength, but therefore have a large load on the mold during molding and springback after molding, and are accurate products. The current situation is that the ease of processing for obtaining shape and dimensional accuracy is not always satisfied.

For example, Patent Document 1 describes Cu as 0.05% to 0.15%, Si as 0.1% or less, Fe as 0.05% to 0.2%, and Mg as 0.2% to 0.4. An Al alloy containing% or less and containing at least one of Ti 0.1% or less and B 0.01% or less, which is excellent in brilliant alumite property, deep drawing property, and rough skin resistance at the time of deep drawing. The plate and its manufacturing method are disclosed.

Patent Document 2 contains 1.5% to 5.0% of Mg, 0.005% to 0.20% of Ti, 0.01% to 0.30% of Cu, and 0.05% of Mn. % To 0.60%, Cr 0.05% to 0.40%, Zr 0.05% to 0.30%, V 0.05% to 0.20%, B 0.0005% to Spinning workability that contains one or more of 0.05% and suppresses Fe as impurities to 0.10% or less, Si to 0.10% or less, and other impurities alone to 0.05% or less. Further, an Al alloy having excellent brilliance and a method for producing the same are disclosed.

Patent Document 3 contains Si of 0.10% or less, Fe of 0.10% or less, Cu of 0.01% to 0.10%, Mg of 1.5% to 3.0%, and the balance. A method for producing an Al alloy plate having excellent brilliant alumite properties, which is composed of Al and unavoidable impurities, is disclosed.

Patent Document 4 contains 0.05% to 0.15% of Fe, 0.06% to 0.15% of Cu, 0.004% to 0.04% of Ti, and Si and Mg as impurities. And Mn is 0.08% or less, and an Al alloy plate for a lighting reflector in which the balance is Al and unavoidable impurities and a method for producing the same are disclosed.

In Patent Document 5, Fe is 0.005% to 0.05%, Si is 0.005% to 0.05%, Cu is 0.01% to 0.1%, and Cr is 0.05% to 0. Disclosed is an Al alloy containing .30% and 2.5% to 3.5% of Mg, and the balance of which is Al and impurities, which is excellent in deep drawing property, dent resistance and appearance.

Japanese Unexamined Patent Publication No. 57-51249 Japanese Unexamined Patent Publication No. 62-23973 Japanese Unexamined Patent Publication No. 62-270757 Japanese Unexamined Patent Publication No. 8-269605 Japanese Unexamined Patent Publication No. 2007-204842

However, although Patent Document 1 is satisfied with the electrolytic polishing property, the chemical polishing property, and the gloss after alumite, the study on the strength is not always sufficient.

Patent Document 2 is an application example to an application that requires extremely high strength, and since the target molding processing method is different, the brilliance is satisfied, but a thin plate drawing material such as a cosmetic case or a cap is satisfied. The material is not suitable for use.

Patent Document 3 discloses a method for manufacturing a medium-strength aluminum alloy plate, which requires higher strength than Patent Document 1. In this document, although the brilliance is examined, the moldability is examined only for the bendability and the overhangability, and the deep drawing property essential for the use of thin plate drawing materials such as cosmetic cases and caps. Has not been considered.

Patent Document 4 aims to reduce the yield strength by adding Fe, Cu, and Ti to a pure aluminum base, but it is a thin plate and has a top and side surface molding process like a cosmetic case. For different shapes, the morphological maintenance (dent resistance, etc.) of the portion having a low degree of molding process and less work hardening is remarkably inferior, so that problems such as dents during handling have not been solved.

Patent Document 5 discloses that Fe, Si, Cu, and Cr are added to an Al—Mg system to improve deep drawing property, dent resistance, and appearance (brilliance). Due to the change in color tone after anodizing), there remains the problem that the intended use is limited.

As described above, conventionally, it is possible to obtain an aluminum alloy plate which is a brilliant aluminum material used for lighting equipment applications, applications requiring design and decorativeness, and has both brilliance and processability. There was the problem that it was very difficult.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rolled aluminum alloy material having excellent brilliance and workability and a method for producing the same.

As a result of diligent research, the inventor of the present application examined the composition of the rolled aluminum alloy material and the manufacturing process of the rolled aluminum alloy material, and as a result, the rolled aluminum alloy material having excellent brilliance and workability. It was found that the above was obtained, and the present invention was made.

That is, the present invention comprises the following means.

[1] Si: 0.02% by mass to 0.08% by mass, Fe: 0.02% by mass to 0.08% by mass, Cu: 0.06% by mass to 0.15% by mass, Mn: 0.0005 Mass% to 0.01% by mass, Mg: 0.42% by mass to 0.75% by mass, Ni: 0.001% by mass to 0.1% by mass, Zn: 0.001% by mass to 0.1% by mass , Ti: 0.0005% by mass to 0.04% by mass, Ga: 0.0002% by mass to 0.01% by mass, B: 0.0002% by mass to 0.01% by mass, and the balance is Al. It has a chemical composition consisting of unavoidable impurities and has a chemical composition.
In addition, the tensile strength is 100 MPa or more and 180 MPa or less, the conductivity is 50% IACS or more, and the liquid temperature is 90 ° C. with a chemical polishing liquid consisting of phosphoric acid: 70% by volume, nitric acid: 5% by volume, and the balance water. , An aluminum alloy rolled material characterized by having a reflectance of 65% or more after a chemical polishing treatment for a time of 120 seconds.

[2] Cu: 0.08% by mass to 0.12% by mass, Mn: 0.001% by mass to 0.005% by mass, Ni: 0.002% by mass to 0.05% by mass, Zn in the chemical composition. : 0.002% by mass to 0.05% by mass, Ti: 0.005% by mass to 0.04% by mass, Ga: 0.002% by mass to 0.05% by mass, B: 0.001% by mass to 0 It is 0.02% by mass,
The rolled aluminum alloy material according to the preceding item [1], which has a tensile strength of 125 MPa or more and 165 MPa or less and a conductivity of 52% IACS or more.

[3] Cr in the unavoidable impurities in the chemical composition is 0.01% by mass or less, V is 0.015% by mass or less, Zr is 0.015% by mass or less, Ca is 0.005% by mass or less, and Pb is 0. The aluminum alloy according to the preceding item [1] or [2], which is restricted to .005% by mass or less, Bi is 0.005% by mass or less, Sn is 0.005% by mass or less, and In is 0.005% by mass or less. Rolled material.

[4] Si: 0.02% by mass to 0.08% by mass, Fe: 0.02% by mass to 0.08% by mass, Cu: 0.06% by mass to 0.15% by mass, Mn: 0.0005 Mass% to 0.01% by mass, Mg: 0.42% by mass to 0.75% by mass, Ni: 0.001% by mass to 0.1% by mass, Zn: 0.001% by mass to 0.1% by mass , Ti: 0.0005% by mass to 0.04% by mass, Ga: 0.0002% by mass to 0.01% by mass, B: 0.0002% by mass to 0.01% by mass, and the balance is Al. For aluminum alloy ingots having a chemical composition consisting of unavoidable impurities
Before or after the surface milling carried out on the ingot, homogenization treatment is carried out at a temperature of 500 ° C. or higher and 580 ° C. or lower for 1 hour or longer and 20 hours or lower, and 0 at a temperature of 480 ° C. or higher and 550 ° C. or lower. Hot rolling is started after holding for 5 hours or more and 10 hours, and after performing hot rolling with a reduction ratio of 95% or more and 99.5% or less by a plurality of reduction passes, the reduction ratio is 55% or more and 98. A method for producing an aluminum alloy rolled material, which comprises performing cold rolling of 5% or less to obtain an aluminum alloy rolled material.

[5] Cu: 0.08% by mass to 0.12% by mass, Mn: 0.001% by mass to 0.005% by mass, Ni: 0.002% by mass to 0.05% by mass, Zn in the chemical composition. : 0.002% by mass to 0.05% by mass, Ti: 0.005% by mass to 0.04% by mass, Ga: 0.002% by mass to 0.05% by mass, B: 0.001% by mass to 0 The method for producing a rolled aluminum alloy according to the preceding item [4], which is 0.02% by mass.

[6] Cr in the unavoidable impurities in the chemical composition is 0.01% by mass or less, V is 0.015% by mass or less, Zr is 0.015% by mass or less, Ca is 0.005% by mass or less, and Pb is 0. The aluminum alloy according to the preceding item [4] or [5], which is restricted to .005% by mass or less, Bi is 0.005% by mass or less, Sn is 0.005% by mass or less, and In is 0.005% by mass or less. Manufacturing method of rolled material.

[7] The previous section [4] to [6], in which the annealing step is carried out at least once before and after any of the passes in cold rolling by holding at 220 ° C. or higher and 380 ° C. or lower and 0.5 hours or longer for 12 hours. The method for producing a rolled aluminum alloy according to any one of the above items.

[8] Any of the above items [4] to [7], in which the annealing step is carried out at least once after cold rolling by holding at 150 ° C. or higher and 300 ° C. or lower and 0.5 hours or longer and 12 hours or lower. The method for producing a rolled aluminum alloy according to item 1.

[9] After molding the rolled aluminum alloy according to any one of the above items [1] to [3], phosphoric acid: 70% by volume to 80% by volume, nitric acid: 5% by volume to 10% by volume, nitric acid. A chemical polishing liquid consisting of copper: 0.2% by mass to 0.8% by volume and the balance water is subjected to chemical polishing treatment at a liquid temperature of 90 to 100 ° C. and a time of 60 to 180 seconds, and then washed and dried. A method for producing a brilliant molded product, which is characterized in that it is later subjected to an alumite treatment of 4 to 10 μm to have a reflectance of 60% or more.

[10] After molding the rolled aluminum alloy obtained by the production method according to any one of the above items [4] to [8], phosphoric acid: 70% by volume to 80% by volume and nitric acid: 5% by volume. Chemical polishing treatment consisting of ~ 10% by volume, copper nitrate: 0.2% by mass ~ 0.8% by mass, and residual water at a liquid temperature of 90 to 100 ° C. and a time of 60 seconds to 180 seconds. A method for producing a brilliant molded product, which is carried out, washed with water, dried, and then subjected to an alumite treatment of 4 to 10 μm to have a reflectance of 60% or more.

According to the rolled aluminum alloy material of the invention [1], Si: 0.02% by mass to 0.08% by mass, Fe: 0.02% by mass to 0.08% by mass, Cu: 0.06% by mass to 0. .15% by mass, Mn: 0.0005% by mass to 0.01% by mass, Mg: 0.42% by mass to 0.75% by mass, Ni: 0.001% by mass to 0.1% by mass, Zn: 0 .001% by mass to 0.1% by mass, Ti: 0.0005% by mass to 0.04% by mass, Ga: 0.0002% by mass to 0.01% by mass, B: 0.0002% by mass to 0.01 It contains mass%, has a chemical composition in which the balance is composed of Al and unavoidable impurities, has a tensile strength of 100 MPa or more and 180 MPa or less, a conductivity of 50% IACS or more, and a phosphoric acid: 70% by mass. A chemical polishing liquid consisting of nitric acid: 5% by mass and the balance of water has a reflectance of 65% or more after a chemical polishing treatment at a liquid temperature of 90 ° C. and a time of 120 seconds, so that excellent brilliance and workability can be obtained. Can be done.

According to the rolled aluminum alloy material of the invention [2], the rolled aluminum alloy material of the invention [1] further has Cu: 0.08% by mass to 0.12% by mass and Mn: 0.001 in the chemical composition. Mass% to 0.005% by mass, Ni: 0.002% by mass to 0.05% by mass, Zn: 0.002% by mass to 0.05% by mass, Ti: 0.005% by mass to 0.04% by mass , Ga: 0.002% by mass to 0.05% by mass, B: 0.001% by mass to 0.02% by mass, and a tensile strength of 125 MPa or more and 165 MPa or less and a conductivity of 52% IACS or more. Therefore, more excellent brilliance and processability can be obtained.

According to the aluminum alloy rolled material of the invention [3], in the aluminum alloy rolled material of the invention [1] or [2], Cr in the unavoidable impurities in the chemical composition is 0.01% by mass or less, and V is 0.015% by mass or less, Zr is 0.015% by mass or less, Ca is 0.005% by mass or less, Pb is 0.005% by mass or less, Bi is 0.005% by mass or less, Sn is 0.005% by mass. Hereinafter, since In is restricted to 0.005% by mass or less, even more excellent brilliance and processability can be obtained.

According to the production methods of the inventions [4] to [6], the temperature of an aluminum alloy ingot having a predetermined chemical composition is 500 ° C. or higher and 580 ° C. or lower before or after rolling on the ingot. The homogenization treatment was carried out in 1 hour or more and 20 hours or less, and hot rolling was started after holding at a temperature of 480 ° C or more and 550 ° C or less for 0.5 hours or more and 10 hours. Since hot rolling of 95% or more and 99.5% or less is carried out and then cold rolling of a reduction ratio of 55% or more and 98.5% or less is carried out at least once, an aluminum alloy rolled material is obtained. An aluminum alloy rolled material having excellent brilliance and processability can be obtained.

According to the manufacturing method of the invention [7], it is the manufacturing method of the inventions [4] to [6], and further, at least once before and after any one pass in cold rolling, 220 ° C. or higher and 380 ° C. or lower, 0. Since the annealing step is carried out by holding for 5 hours or more and 12 hours, an aluminum alloy rolled material having more excellent brilliance and processability can be obtained.

According to the manufacturing method of the invention [8], it is the manufacturing method of the inventions [4] to [7], and further, at least once after cold rolling, 150 ° C. or higher and 300 ° C. or lower, 0.5 hours or longer. Since the annealing step is carried out by holding for 12 hours or less, it is possible to obtain an aluminum alloy rolled material having even more excellent brilliance and processability.

According to the production method of the invention [9], after molding the rolled aluminum alloy material of the inventions [1] to [3], phosphoric acid: 70% by volume to 80% by volume, nitric acid: 5% by volume to 10% by volume, Copper nitrate: 0.2% by volume to 0.8% by volume, with a chemical polishing liquid consisting of the balance water, liquid temperature: 90 to 100 ° C., time: 60 to 180 seconds, chemical polishing treatment, washing with water, After drying, it is subjected to an alumite treatment of 4 to 10 μm to have a reflectance of 60% or more, so that a brilliant molded body having excellent brilliance and processability can be obtained.

According to the production method of the invention [10], after molding the aluminum alloy rolled material obtained by the production methods of the inventions [4] to [8], phosphoric acid: 70% by volume to 80% by volume, nitrate: 5 volumes. Chemical polishing treatment consisting of% to 10% by volume, copper nitrate: 0.2% by volume to 0.8% by volume, and residual water at a liquid temperature of 90 to 100 ° C. and a time of 60 to 180 seconds. After washing with water and drying, an alumite treatment of 4 to 10 μm is performed to obtain a reflectance of 60% or more, so that a brilliant molded body having excellent brilliance and processability can be obtained.

In the manufacturing method for producing an aluminum alloy rolled material by sequentially performing hot rolling and cold rolling on an ingot for an aluminum alloy rolled material, the inventor of the present application uses Al to ensure uniform melting during chemical polishing. By controlling the material strength and conductivity while suppressing the generation of intermetallic compounds formed by elements such as Si, Fe, Cu, Mn, Mg, Ni, Zn, Ti, and B, brilliance and workability. It has been found that an excellent rolled aluminum alloy can be obtained, and the present invention has been made.

Hereinafter, the configuration of the rolled aluminum alloy material of the present invention will be described in detail.

In the alloy composition (chemical composition) of the rolled aluminum alloy of the present application, the purpose of adding each element and the reason for limiting the content are as follows.

(Si content)
Si raises the recrystallization temperature and suppresses the coarsening of crystal grains. In order to obtain this effect, the content must be at least the lower limit. On the other hand, if it is excessively contained, a simple substance or an Al—Fe—Si-based intermetallic compound is formed, and the periphery of the intermetallic compound is likely to be locally melted during the chemical polishing treatment to form fine irregularities, resulting in a decrease in reflectance. In addition, the intermetallic compound mixed in the anodic oxide film inhibits the transparency of the film. Therefore, in the present invention, the Si content is 0.02% by mass or more and 0.08% by mass or less (similar to 0.02% by mass to 0.08% by mass, the same applies hereinafter). The Si content is preferably 0.025% by mass or more and 0.06% by mass or less, and more preferably 0.03% by mass or more and 0.05% by mass or less.

(Fe content)
Fe raises the recrystallization temperature and refines the crystal grains to improve the material strength. In order to obtain this effect, the content must be at least the lower limit. On the other hand, if it is excessively contained, an Al—Fe-based intermetallic compound is excessively formed, and the periphery of the intermetallic compound is likely to be locally dissolved during the chemical polishing treatment to form fine irregularities, resulting in a decrease in reflectance. In addition, the intermetallic compound mixed in the anodic oxide film inhibits the transparency of the film. In the present invention, the Fe content is 0.02% by mass or more and 0.08% by mass or less. The Fe content is preferably 0.025% by mass or more and 0.06% by mass or less, and more preferably 0.03% by mass or more and 0.05% by mass or less.

(Cu content)
Cu is an element effective for improving strength. Further, it has an effect of making chemical polishing or surface unevenness uniform by dissolving in Al and reducing the potential difference between the Al material and various intermetallic compounds. In order to obtain this effect, it is necessary to contain more than the lower limit. On the other hand, if it is excessively contained, coarse Al—Cu-based intermetallic compounds are likely to precipitate, and are likely to be the starting points of cracks in deep drawing. In addition, the color tone of the film tends to turn yellow during anodization. If it is contained in a larger amount, the corrosion resistance is lowered. Therefore, the range of Cu content is 0.06% by mass or more and 0.15% by mass or less. Further, it is preferably 0.08% by mass or more and 0.12% by mass or less, and particularly preferably 0.09% by mass or more and 0.11% by mass or less.

(Mn content)
Mn is an alloy element generally added for the miniaturization of recrystallized grains, but on the other hand, when added more than necessary, an Al—Fe—Mn-based intermetallic compound is formed, and the metal is formed during the chemical polishing treatment. The periphery of the intermetallic compound is likely to dissolve locally to form fine irregularities, and the reflectance is lowered. Further, when Mn is incorporated into the film during the formation of the anodic oxide film, the color tone of the film becomes brown. Therefore, the Mn content is preferably 0.0005% by mass or more and 0.01% by mass or less. Further, it is preferably 0.001% by mass or more and 0.008% by mass or less, and further preferably 0.002% by mass or more and 0.005% by mass or less.

(Mg content)
Mg is an element that greatly contributes to the improvement of strength by being dissolved in Al. However, in the present invention, there is an optimum value for ensuring easy workability at the time of product processing. On the other hand, if it is contained in an excessive amount, it tends to crack in deep drawing and is mixed in the anodic oxide film to impair the transparency of the film. For the above reasons, the Mg content is set in the range of 0.42% by mass or more and 0.75% by mass or less. Further, it is preferably 0.45% by mass or more and 0.65% by mass or less, and particularly preferably 0.50% by mass or more and 0.60% by mass or less.

(Zn content)
If the amount of Zn is small, it dissolves in Al, so that local dissolution due to the intermetallic compound during chemical polishing does not occur, and it is an element that also contributes to increasing the strength. However, when the content is high, the corrosion resistance of the alloy material is lowered. When the content is further increased, the reflectance at the time of chemical polishing is remarkably lowered due to the fine precipitates due to the coexistence with Mg. Therefore, the Zn content is 0.001% by mass or more and 0.1% by mass or less. Further, it is preferably 0.002% by mass or more and 0.05% by mass or less, and further preferably 0.05% by mass or more and 0.01% by mass or less.

(Ti content)
Ti refines the ingot structure during slab casting of the alloy, prevents the generation of streaks due to coarse recrystallization during hot rolling, and crystallized during annealing before and after the cold rolling pass. It has the effect of reducing the diameter to prevent rough skin during molding. However, if it is contained in a large amount, a large amount of crystallized products having a large size are produced, so that the reflectance during chemical polishing is lowered. Therefore, the Ti content is Ti: 0.0005% by mass or more and 0.04% by mass or less. Further, it is preferably 0.005% by mass or more and 0.03% by mass or less, and more preferably 0.008% by mass or more and 0.02% by mass or less.

(Ni content)
Ni is an element effective for improving strength if it is used in a small amount. Also. The color change during anodization is not as large as Fe and Cr. However, when added in a large amount, an Al—Fe—Ni-based intermetallic compound is formed, and the periphery of the intermetallic compound is easily dissolved locally during the chemical polishing treatment to form fine irregularities, resulting in a decrease in reflectance. Therefore, the Ni content is 0.001% by mass or more and 0.1% by mass or less. Further, it is preferably 0.002% by mass or more and 0.05% by mass or less, and further preferably 0.01% by mass or more and 0.03% by mass or less.

(Ga content)
Since Ga is a solid solution in Al, local dissolution by intermetallic compounds during chemical polishing does not occur, and it is an element that contributes to an increase in strength. However, if it is contained in a large amount, it tends to segregate at the grain boundaries and the interface of the crystallized material, so that surface cracks occur in hot rolling and cold rolling, which deteriorates workability. Therefore, the Ga content is 0.001% by mass or more and 0.1% by mass or less. Further, it is preferably 0.002% by mass or more and 0.05% by mass or less, and further preferably 0.01% by mass or more and 0.03% by mass or less.

(B content)
B has the effect of refining the crystal structure of the ingot. However, if it is contained in a large amount, a large amount of hard crystallization is generated, so that the reflectance at the time of chemical polishing is lowered. Therefore, the B content is 0.0005% by mass or more and 0.04% by mass or less. Further, it is preferably 0.001% by mass or more and 0.02% by mass or less, and more preferably 0.003% by mass or more and 0.01% by mass or less.

(Cr content)
Cr is known as an element effective for improving strength and refining crystal grains, but on the other hand, it lowers processability during hot rolling. In addition, it precipitates as an intermetallic compound and the reflectance during chemical polishing decreases. In addition, the color tone of the film tends to turn black during anodizing. If it is further contained in an excessive amount, the film becomes cloudy due to the coarse intermetallic compound. Therefore, the range of the content of Cr as an unavoidable impurity is 0.01% by mass or less. Further, it is preferably 0.008% by mass or less, and particularly preferably 0.0005% by mass or less.

(V content)
V tends to segregate at the grain boundaries, and the ductility decreases as the V content increases, so a small amount is preferable. Therefore, the V content as an unavoidable impurity is 0.015% by mass or less. Further, it is preferably 0.01% by mass or less, and more preferably 0.005% by mass or less.

(Zr content)
Zr tends to segregate at the grain boundaries, and the ductility decreases as the Zr content increases, so a small amount is preferable. Further, if it is contained in an excessive amount, a fine intermetallic compound with Al is formed, and the reflectance at the time of chemical polishing is lowered. Therefore, the Zr content as an unavoidable impurity is 0.015% by mass or less. Further, it is preferably 0.01% by mass or less, and more preferably 0.005% by mass or less.

(Ca content)
When Ca is contained in a large amount, ductility is reduced. Therefore, the Ca content as an unavoidable impurity is preferably 0.005% by mass or less, more preferably 0.004% by mass or less, and particularly preferably 0.003% by mass or less.

(In content)
It is preferable that the amount of In is small because it significantly lowers the corrosion resistance. The In content as an unavoidable impurity is preferably 0.005% by mass or less, more preferably 0.004% by mass or less, and particularly preferably 0.003% by mass or less.

(Pb, Bi, Sn content)
Pb, Bi, and Sn have extremely low solid solution limits in aluminum and are likely to precipitate at grain boundaries. Therefore, the content of each element as an unavoidable impurity is preferably 0.005% by mass or less, further preferably 0.004% by mass or less, and particularly preferably 0.003% by mass or less. ..

Next, a processing process for obtaining the rolled aluminum alloy material specified in the present application will be described.

The dissolution component is adjusted by a conventional method to obtain an aluminum alloy ingot having the above alloy composition. It is preferable to subject the obtained alloy ingot to a homogenization treatment as a step prior to heating before hot rolling.

The homogenization treatment is carried out in order to make the concentration of elements that dissolve in the aluminum alloy ingot uniform. However, if the temperature is too high, eutectic melting occurs and causes cracking during hot rolling. Therefore, 500 The temperature is preferably 520 ° C or higher and 580 ° C or lower, and particularly preferably 520 ° C or higher and 560 ° C or lower. The time is preferably 1 hour or more and 20 hours or less, and particularly preferably 2 hours or more and 15 hours or less.

After the aluminum alloy ingot is homogenized, it is heated before hot rolling. The preferable temperature range for heating before hot rolling is 480 ° C. or higher and 550 ° C. or lower. The time is preferably 0.5 hours or more and 10 hours or less. A more preferable range is a temperature of 490 ° C. or higher and 530 ° C. or lower, and an hour of 1 hour or more and 8 hours or less. In addition, you may heat at the same temperature for both the homogenization treatment and the hot rolling preheating in the preferable temperature range of both the homogenization treatment and the hot rolling preheating.

After casting, before hot rolling, before heating, it is preferable to face-cut the ingot in order to remove the impurity layer near the surface of the ingot. The face milling may be performed after casting and before homogenization treatment, or after homogenization treatment and before hot rolling and before heating.

Before hot rolling Hot rolling is performed on the aluminum alloy ingot after heating. Hot rolling consists of rough hot rolling and finish hot rolling. After performing rough hot rolling consisting of multiple passes using a rough hot rolling machine, a finishing hot rolling machine different from the rough hot rolling machine Is used for finishing hot rolling.

In order to sufficiently form the crystal structure in the hot rolling and the subsequent manufacturing process, the total hot rolling reduction ratio (rough + finish) is 95% or more. Further, the hot rolling ascending temperature is preferably 200 ° C. or higher and 350 ° C. or lower. When the hot rolling rise temperature is 200 ° C or less, recrystallization during hot rolling does not proceed sufficiently, and when the final rolled plate is drawn by deep drawing, spinning, etc., the ear ratio becomes high and the flow line becomes high. It occurs and the appearance is poor. Further, at 350 ° C. or higher, the crystal grain size after hot rolling becomes large, so that the crystal grain size of the final rolled plate becomes large, and rough skin occurs after drawing.

In the present application, when the final pass in the rough hot rolling mill is the final pass for hot rolling, the finishing hot rolling can be omitted.

When cold rolling is carried out with a coil, the aluminum alloy rolled material after finishing hot rolling may be wound by a winding device to form a hot-rolled coil. When finishing hot rolling is omitted and the final pass of hot rough rolling is the final pass of hot rough rolling, after hot rough rolling, the aluminum alloy rolled material is wound by a take-up device and hot-rolled coil. May be.

After the completion of hot rolling, the rolling reduction ratio of cold rolling until an aluminum alloy rolled material having a predetermined thickness is obtained is preferably 55% or more in order to obtain a predetermined strength. The rolling ratio of the rolled aluminum alloy material by cold rolling is more preferably 70% or more, and particularly preferably 85% or more. The upper limit of the reduction rate shall be 98.5% or less.

After the completion of hot rolling, the aluminum alloy rolled material can be annealed before and after cold rolling or between the passes to improve the mechanical properties and the deep drawing / spinning ability. In the present invention, it is desirable to perform annealing at a temperature of 220 ° C. or higher and 380 ° C. or lower at least once in order to obtain the above effects. Further, the temperature is preferably 240 ° C. or higher and 340 ° C. or lower, and particularly preferably the temperature of 260 ° C. or higher and 320 ° C. or lower.

After the completion of the hot rolling, the annealing time of the rolled aluminum alloy material before and after the cold rolling or between the passes is preferably 0.5 hours or more and 12 hours or less. Further, it is preferably 1 hour or more and 8 hours or less, and particularly preferably 2 hours or more and 6 hours or less.

When cold rolling is carried out after the annealing, the strength is improved by work hardening. However, if the degree of processing is too high, it causes elongation and deterioration of deep drawing and spinning. When cold rolling is performed after annealing, the cold rolling reduction rate is preferably 10% or more and 40% or less. Further, 15% or more and 35% or less are preferable, and 20% or more and 30% or less are particularly preferable.

Further, by performing annealing after the step of cold rolling is completed, it is possible to recover the decrease in elongation due to cold rolling without causing a significant decrease in strength. In the present invention, in order to obtain the above effect, it is preferable to carry out annealing at least once by holding at 150 ° C. or higher and 300 ° C. or lower and 0.5 hours or longer and 12 hours or lower. Further, 180 ° C. or higher and 280 ° C. or lower are preferable, 1 hour or more and 8 hours or less, and particularly 200 ° C. or higher and 250 ° C. or lower, 2 hours or more and 6 hours or lower are more preferable.

A step of trimming the ear crack portion at the end of the plate width and further proceeding with cold rolling to prevent plate breakage may be included before cold rolling or between cold rolling passes.

Further, the rolled aluminum alloy material after cold rolling may be washed if necessary.

The rolled aluminum alloy material of the present invention may be produced by a coil or a veneer. Further, the rolled aluminum alloy material may be cut in an arbitrary step after the cold rolling and the step after the cutting may be performed on a single plate, or may be slit and stripped according to the application.

The tensile strength (symbol σ _B ) of the rolled aluminum alloy of the present invention is defined as 100 ≤ σ _B ≤ 180 MPa, and the elongation conductivity (symbol Σ) is defined as Σ ≧ 50% IACS. It is preferable that the tensile strength σ _B is 125 ≦ σ _B ≦ 165 MPa and the conductivity Σ is 52% IACS or more. By satisfying the tensile strength and conductivity specified in the present invention, a rolled aluminum alloy material having excellent brilliance and workability can be obtained.

The thin aluminum alloy plate is further subjected to a desired molding process. In the processing, deep drawing and spinning are possible, and it is possible to obtain a molded body by molding into various shapes without causing cracking. After that, buffing, chemical polishing, and anodizing are performed.

In the chemical polishing treatment, a polishing liquid containing phosphoric acid, nitric acid, and copper nitrate is recommended, but other treatment conditions are not particularly limited, and various known methods can be used.

Further, in the anodizing treatment, although the film thickness is recommended to be 4 to 10 μm, other treatment conditions are not particularly limited, and various known methods can be used.

According to the above manufacturing method, it has a certain strength and has appropriate workability for deep drawing, spinning, etc., has excellent brilliance after chemical polishing and alumite treatment after molding, and is dented during use. An aluminum alloy rolled material that is resistant to deformation can be obtained.

Further, by using the rolled aluminum alloy obtained by the present invention, it is possible to surely obtain a brilliant molded body such as a cosmetic case, a cap, a reflector for automobiles and interior lighting, and a decorative item.

Hereinafter, the present invention will be described by way of examples. It should be noted that the present invention does not limit the scope of the invention to the examples described here, and it is also possible to carry out the present invention with appropriate modifications within the range suitable for the gist of the present invention. It is included in the technical scope of the present invention.

Table 1 shows the chemical compositions (C1 to C12) of each aluminum alloy slab (aluminum alloy ingot) prepared in this example. The chemical compositions of C1 to C6 are included in the chemical composition related to the present invention (the chemical composition of claim 1), and the chemical compositions of C7 to C12 deviate from the chemical composition related to the present invention. be.

Table 2 shows various manufacturing processes (P1 to P11) carried out when the rolled material is manufactured in this embodiment. The manufacturing processes of P1 to P6 are included in the manufacturing process (manufacturing step of claim 4) related to the present invention, and the manufacturing steps of P7 to P11 are manufactured in which any of the processing steps is related to the present invention. It deviates from the process.

In addition, Table 3 contains information on which of the manufacturing steps (P1 to P11) in Table 2 was carried out for each alloy slab having the chemical composition (C1 to C12) in Table 1. For example, in Examples 1 to 6, the manufacturing steps P1 to P6 were carried out for each alloy slab having a chemical composition C1 to C6, and in Comparative Examples 7 to 12, each alloy slab having a chemical composition C7 to C12 was carried out. On the other hand, the manufacturing processes P10, P7, P6, P8, P9, and P11 were carried out, respectively.

Specifically, the aluminum alloy slab having the chemical composition shown in Table 1 is face-cut, and then the alloy slab after the face-cutting is subjected to the homogenization treatment shown in Table 2 in a heating furnace, and then in the same furnace. After the temperature is lowered to the temperature before hot rolling shown in Table 2, the temperature is maintained after reaching the heating temperature shown in Table 2, and hot rolling is carried out under the conditions shown in Table 2. A rolled plate was obtained. After the hot-rolled finish, the alloy plate is subjected to the intermediate heat treatment, cold rolling, and final heat treatment shown in Table 2, and the aluminum alloy plate (aluminum alloy rolled material) having a predetermined plate thickness in Examples 1 to 6 and Comparative Examples 7 to 12 is applied. ) Was obtained.

The tensile strength, conductivity, and ear ratio of each alloy plate thus obtained were measured and evaluated by the following methods. The evaluation results are also shown in Table 3.

[Tensile strength, proof stress, elongation]
The tensile strength (σ _B ), proof stress (σ _0.2 ) and elongation (δ) were measured at room temperature and by a conventional method for a sample collected in a direction parallel to the rolling direction with a JIS No. 5 test piece defined in JIS Z2201. .. Then, those having 100 ≦ σ _B ≦ 180 MPa and δ ≧ 10% were designated as “◯”.

[conductivity]
The conductivity of the obtained alloy plate was determined as a relative value (% IACS) when the conductivity of the internationally adopted annealed standard annealed copper (volume low efficiency 1.7241 × 10-2 μΩm) was 100% IACS. rice field.

Each of the plate materials of Examples 1 to 6 and Comparative Examples 7 to 12 was punched into a circle of 90 mmφ to form a blank, and each blank was deep-drawn to form a blank in Examples 1 to 6 and Comparative Examples 7 to 12. , A cylindrical container having a bottom surface of 50 mmφ and a shoulder R of 2.0 mm was prepared.

The heights of the side walls of the cylindrical containers of Examples 1 to 6 and Comparative Examples 7 to 12 were measured at a total of 8 points at a pitch of 45 ° in the circumferential direction, and the ear ratio was obtained from the calculation as shown in the following formula.

Ear ratio (%) = (H ₄₅ -H _0-90 ) / {(H ₄₅ + H _0-90 ) / 2} x 100
here,
・ H ₄₅ : Average height of 45 ° ears (4 points),
・ H _0-90 : 0 °, 90 ° Average height of ears (4 points),
-{(H ₄₅ + H _0-90 ) / 2}: Average height of all measurement points (8 points),
Is. The number of times the ear rate is measured is n = 3, and the average value of the three values is used. The ear ratio in this molding application was 18% or less, and the one that could not be molded into the shape of a cylindrical container and was broken was marked with "x".

Next, the cylindrical container was subjected to a chemical polishing treatment at a liquid temperature of 90 ° C. and a time of 120 seconds with a chemical polishing liquid consisting of phosphoric acid: 70% by volume, nitric acid: 5% by volume, and residual water. Further, anodizing treatment (anodizing treatment) was carried out in a 15% by volume sulfuric acid solution at a liquid temperature of 20 ° C. and 15 V for 10 minutes, and after washing with water, a pore-sealing treatment was carried out with warm water at 90 ° C. for 15 minutes. The reflectance of the bottom surface of the cup was measured after chemical polishing and after anodizing. The method for measuring the reflectance is as follows.

[Reflectance]
The reflectance evaluation was carried out according to the method specified in JISZ8741 Mirror gloss measuring method and (reference) 45 degree mirror reflectance measuring method of aluminum and aluminum alloy anodic oxide film. For those that could not be formed into the shape of a cylindrical container and were broken, the reflectance was not measured after chemical polishing and after anodizing, and was marked as "-".

With the bottom surface of the deep-drawn cup material as the upper surface, a steel ball was dropped into the substantially center of the cylindrical container, and the dent resistance was measured. The measurement conditions are as follows.

-Steel ball diameter: 11.0 mmφ, weight: 5.5 g
・ Drop height: 100 mm
・ Recess measuring device: Stylus type surface shape measuring device ・ Number of measurements: n = 5
[Dent resistance]
In the evaluation of dent resistance, a steel ball is dropped from the above-mentioned predetermined height, the amount of dent from the periphery is measured, and the maximum value is 100 μm or less as “○” and the maximum value exceeds 100 μm as “×”. did. For those that could not be formed into the shape of a cylindrical container and were broken, the dent resistance evaluation was not performed and the value was set to "-".

As shown in Table 3, the rolled aluminum alloy materials of Examples 1 to 6 satisfying the chemical composition, tensile strength and conductivity specified in the present application could be obtained.

The rolled aluminum alloy material of the present invention has a certain strength and has appropriate workability for deep drawing, spinning, etc., is excellent in chemical polishing after molding, and has excellent brilliance after alumite treatment, and is used. It can be used as an aluminum alloy plate that is resistant to dents and deformation.

Claims (10)

Si: 0.02% by mass to 0.08% by mass, Fe: 0.02% by mass to 0.08% by mass, Cu: 0.06% by mass to 0.15% by mass, Mn: 0.0005% by mass to 0.01% by mass, Mg: 0.42% by mass to 0.75% by mass, Ni: 0.001% by mass to 0.1% by mass, Zn: 0.001% by mass to 0.1% by mass, Ti: Contains 0.0005% by mass to 0.04% by mass, Ga: 0.0002% by mass to 0.01% by mass, B: 0.0002% by mass to 0.01% by mass, and the balance is from Al and unavoidable impurities. Has a chemical composition of
In addition, the tensile strength is 100 MPa or more and 180 MPa or less, the conductivity is 50% IACS or more, and the liquid temperature is 90 ° C. with a chemical polishing liquid consisting of phosphoric acid: 70% by volume, nitric acid: 5% by volume, and the balance water. , An aluminum alloy rolled material characterized by having a reflectance of 65% or more after a chemical polishing treatment for a time of 120 seconds. Cu: 0.08% by mass to 0.12% by mass, Mn: 0.001% by mass to 0.005% by mass, Ni: 0.002% by mass to 0.05% by mass, Zn: 0. 002 mass% to 0.05 mass%, Ti: 0.005 mass% to 0.04 mass%, Ga: 0.002 mass% to 0.05 mass%, B: 0.001 mass% to 0.02 mass % And
The rolled aluminum alloy material according to claim 1, wherein the tensile strength is 125 MPa or more and 165 MPa or less, and the conductivity is 52% IACS or more. Cr in the unavoidable impurities in the chemical composition is 0.01% by mass or less, V is 0.015% by mass or less, Zr is 0.015% by mass or less, Ca is 0.005% by mass or less, and Pb is 0.005% by mass. The aluminum alloy rolled material according to claim 1 or 2, wherein Bi is 0.005% by mass or less, Sn is 0.005% by mass or less, and In is 0.005% by mass or less. Si: 0.02% by mass to 0.08% by mass, Fe: 0.02% by mass to 0.08% by mass, Cu: 0.06% by mass to 0.15% by mass, Mn: 0.0005% by mass to 0.01% by mass, Mg: 0.42% by mass to 0.75% by mass, Ni: 0.001% by mass to 0.1% by mass, Zn: 0.001% by mass to 0.1% by mass, Ti: Contains 0.0005% by mass to 0.04% by mass, Ga: 0.0002% by mass to 0.01% by mass, B: 0.0002% by mass to 0.01% by mass, and the balance is from Al and unavoidable impurities. For aluminum alloy ingots having a chemical composition of
Before or after the surface milling carried out on the ingot, homogenization treatment is carried out at a temperature of 500 ° C. or higher and 580 ° C. or lower for 1 hour or longer and 20 hours or lower, and 0 at a temperature of 480 ° C. or higher and 550 ° C. or lower. Hot rolling is started after holding for 5 hours or more and 10 hours, and after performing hot rolling with a reduction ratio of 95% or more and 99.5% or less by a plurality of reduction passes, the reduction ratio is 55% or more and 98. A method for producing an aluminum alloy rolled material, which comprises performing cold rolling of 5% or less to obtain an aluminum alloy rolled material. Cu: 0.08% by mass to 0.12% by mass, Mn: 0.001% by mass to 0.005% by mass, Ni: 0.002% by mass to 0.05% by mass, Zn: 0. 002 mass% to 0.05 mass%, Ti: 0.005 mass% to 0.04 mass%, Ga: 0.002 mass% to 0.05 mass%, B: 0.001 mass% to 0.02 mass The method for producing a rolled aluminum alloy according to claim 4, wherein the mass is%. Cr in the unavoidable impurities in the chemical composition is 0.01% by mass or less, V is 0.015% by mass or less, Zr is 0.015% by mass or less, Ca is 0.005% by mass or less, and Pb is 0.005% by mass. The method for producing a rolled aluminum alloy according to claim 4 or 5, wherein Bi is 0.005% by mass or less, Sn is 0.005% by mass or less, and In is 0.005% by mass or less. According to any one of claims 4 to 6, the annealing step is carried out at least once before and after any of the passes in cold rolling by holding at 220 ° C. or higher and 380 ° C. or lower and 0.5 hours or longer and 12 hours. The method for manufacturing a rolled aluminum alloy material according to the above method. The aluminum according to any one of claims 4 to 7, wherein the annealing step is carried out by holding at least once at 150 ° C. or higher and 300 ° C. or lower and 0.5 hours or longer and 12 hours or lower after cold rolling. Manufacturing method of rolled alloy material. After molding the rolled aluminum alloy according to any one of claims 1 to 3, phosphoric acid: 70% by volume to 80% by volume, nitrate: 5% by volume to 10% by volume, copper nitrate: 0.2% by volume. A chemical polishing solution consisting of% to 0.8% by volume and the balance of water is subjected to a chemical polishing treatment at a liquid temperature of 90 to 100 ° C. and a time of 60 to 180 seconds. A method for producing a brilliant molded body, which is characterized by being treated to have a reflectance of 60% or more. After molding the rolled aluminum alloy obtained by the production method according to any one of claims 4 to 8, phosphoric acid: 70% by volume to 80% by volume, nitric acid: 5% by volume to 10% by volume, nitric acid. A chemical polishing liquid consisting of copper: 0.2% by mass to 0.8% by mass and the balance water is subjected to chemical polishing treatment at a liquid temperature of 90 to 100 ° C. and a time of 60 to 180 seconds, and then washed and dried. A method for producing a brilliant molded product, which is characterized in that it is later subjected to an alumite treatment of 4 to 10 μm to have a reflectance of 60% or more.