JP2001254137A - Aluminum alloy sheet for emboss forming, and aluminum alloy coated sheet for emboss forming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a firm aluminum alloy sheet for emboss working used for building material such as siding material and coated sheet thereof, in which cracks are harldly generated at the time of embossing while satisfying the required thinning in wall thickness. SOLUTION: The claim item 1: an aluminum alloy sheet for emboss forming consisting of a soft material having a composition containing 1.2 t 2.1% Mg, in which the content of Si is prescribed to <=0.3%, and Fe to <=0.3%, and the balance Al with inevitable impurities and having the average crystal grain size of <=60 μm. The claim item 2: an aluminum alloy sheet for emboss forming having a composition containing one or more kinds selected from 0.06 to 0.3% Cu, 0.06 to 0.3% Mn and 0.06 to 0.3% Cr in addition to the above each component. The claim items 3 and 4: aluminum alloy coated sheets for emboss forming in which coating is applied on the surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy plate which has been subjected to painting and embossing and is used as a building material such as a siding material. It relates to an aluminum alloy plate for processing.

[0002]

2. Description of the Related Art As an exterior material of various buildings such as houses, for example, a siding material, a metal plate provided with various patterns by embossing is often used from the viewpoint of design and decorativeness. Conventionally, steel plates were generally used as such embossed metal sheet building materials.However, in the event of a disaster such as an earthquake, lighter ones make it more difficult for houses to collapse, Therefore, aluminum alloy plates are often used as embossed plates for building materials such as siding materials.

In the embossing process, a thin plate is pressed between a pair of dies having pattern-shaped irregularities on the surface opposite to each other, so that the irregularities on the front and back are reversed without substantially changing the plate thickness. In this embossing process, the material plate (blank) is bent, drawn or stretched by the projections of the die, and the surface is constrained by the tool only in the last stage. . In addition, as a method of embossing an aluminum material, a method of continuously forming a pattern using a pair of embossing rolls is also applied. In the continuous embossing using such an embossing roll, the pattern of upper and lower rolls coincides with each other. It becomes important. The embossed patterns when used as building materials such as siding materials include hexagonal patterns, stone wall patterns, pyramid patterns, wood grain patterns, shrinking patterns,
Various types such as a net pattern, a leather pattern, a striped pattern, a stucco pattern, a tread pattern, and the like are known.

Conventionally, as an aluminum alloy which has been embossed and used as a building material such as a siding material or the like, emphasis is mainly placed on workability and corrosion resistance.
In many cases, a 3003 alloy, a 3005 alloy, or a 3004 alloy, which is an l-Mn alloy, is used. When such an aluminum alloy is actually embossed into a building material such as a siding material, final annealing is performed at the end of the plate manufacturing process to finish it as a soft material (O material), and then the plate is painted. Usually, embossing is performed, and in some cases, roll forming is performed after embossing.

[0005]

As an embossed pattern formed on a building material such as a siding material, a deeply carved pattern has recently been preferred in order to increase a sense of quality and a three-dimensional appearance. That is, a material having a large molding depth in embossing is preferred. Specifically, a depth of several times the plate thickness is preferred, for example, a plate thickness of 0.4
In mm, it is often desired that the emboss depth is 1.5 mm or more.

On the other hand, building materials such as siding materials are required to be thinner from the viewpoint of cost saving, and it is strongly desired that embossed building materials be thinner than before. That is, the thickness of the embossed building material is conventionally about 0.5 to 2 mm as a standard, but recently it has been desired to reduce the thickness to about 0.2 mm.

However, Al-Mn-based 3003 alloys and 3004 alloys, which are conventionally used for building materials such as siding materials, have a problem that they cannot sufficiently cope with such a demand for thinning. That is, when the thickness of the 3003 alloy, which has been conventionally used for embossing, is reduced, the stiffness of the plate becomes weak due to low strength, and the handling of the plate during the embossing process and the handling of the product plate after the embossing process are performed. May be difficult. On the other hand, in the case of the 3004 alloy or 3005 alloy having a higher strength than the 3003 alloy, a certain degree of stiffness can be maintained even if the thickness is reduced, but cracks are likely to occur during embossing. There's a problem.

Further, in order to reduce costs, there is a demand to apply an embossing roll, which has been conventionally used for embossing a steel sheet, directly to embossing of an aluminum alloy sheet. Even in the case of an alloy sheet, cracks often occur during embossing in a conventional Al-Mn-based aluminum alloy sheet, and therefore, it is not easy to apply the embossing roll used for the steel sheet as it is to the aluminum alloy sheet. It is the fact that it was being done.

The cracks during the embossing as described above are mainly due to the stress concentration due to the progress of the molding at the places where the upper and lower dies (including the embossing rolls) are strong and the sheet thickness is locally reduced. Is thought to occur, leading to breakage.Thus, by reducing the thickness,
It is considered that cracks are more likely to occur during embossing.

The present invention has been made in view of the above circumstances. Even when the thickness is reduced to 0.5 mm or less, the occurrence of cracks during the embossing process is small, and the embossing process has high strength and strong stiffness. An object of the present invention is to provide an aluminum alloy plate for use.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors of the present invention have conducted intensive experiments and studies. As a result, the alloy system was changed to Al containing a relatively small amount of Mg.
-The above-mentioned object as an aluminum alloy plate for embossing by controlling the amount of Fe and Si as unavoidable impurities to a small amount and appropriately adjusting the crystal grain size of the plate by using a Mg-based alloy. Have been achieved, and the present invention has been accomplished.

More specifically, the aluminum alloy sheet for embossing according to the first aspect of the present invention has a Mg content of 1.2 to 2.1%.
And 0.3% or less of Si and 0.3% or less of Fe, the balance being Al and unavoidable impurities, and a soft material having an average crystal grain size of 60 μm or less. It is a feature.

The aluminum alloy sheet for embossing according to the second aspect of the present invention contains 1.2 to 2.1% of Mg, 0.06 to 0.3% of Cu, and 0.06 to 0.3% of Mn.
3%, one or more of Cr 0.06 to 0.3%, and further, 0.3% or less of Si and 0.3% of Fe.
It is characterized by being restricted to 3% or less, the balance being made of Al and unavoidable impurities, and of a soft material having an average crystal grain size of 60 μm or less.

[0014] Claims 3 and 4 further specify a coated plate obtained by coating the above-mentioned embossed aluminum alloy plate.

More specifically, the aluminum alloy coated plate for embossing according to the third aspect of the present invention has a composition of Mg 1.2-2.
1%, and 0.3% or less of Si and 0.3% of Fe
% Or less, and the balance is made of Al and unavoidable impurities, and is coated on the surface of a soft material having an average crystal grain size of 60 μm or less.

The aluminum alloy coated plate for embossing according to claim 4 contains 1.2 to 2.1% of Mg, 0.06 to 0.3% of Cu, and 0.06 to 0.3% of Mn.
One or more of 0.3% and Cr 0.06 to 0.3% are contained, and the content of Si is regulated to 0.3% or less and the content of Fe is regulated to 0.3% or less. And inevitable impurities, and the average crystal grain size is 60 μm
It is characterized in that the following soft material is coated on the surface.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the reasons for limiting the composition of the aluminum alloy sheet of the present invention will be described.

Mg: Mg is an essential basic component in the aluminum alloy used in the present invention, and is an important element that contributes to improvement in strength, stiffness, and crack resistance during embossing. . Here, the amount of Mg is 1.2%
If it is less than the strength, the strength of the plate is low and the stiffness of the plate is weakened, which may make it difficult to handle the product plate during or after the embossing process, and the effect of improving the crack resistance during the embossing process is small. Become. On the other hand, if the Mg content exceeds 2.1%, the crack resistance during the embossing process is reduced. Therefore, the amount of Mg is 1.2 to
It was within the range of 2.1%.

Fe: Fe is an impurity element inevitably contained in ordinary aluminum alloys. Fe is
An Al-Fe-based or Al-Fe-Si-based intermetallic compound is generated at the time of casting, and these intermetallic compounds are precipitated during homogenization treatment or during heating for subsequent hot rolling. The intermetallic compound serves as a crack initiation site during embossing and facilitates the occurrence of cracks. Particularly, when the Fe content exceeds 0.3%, the cracking resistance during embossing is significantly reduced. Resulting in. Therefore, the Fe content is restricted to 0.3% or less.

Si: Si is also an impurity element inevitably contained in ordinary aluminum alloys. Si is
Generates Al-Fe-Si-based or Mg ₂ Si-based intermetallic compounds during casting, also precipitate these intermetallic compounds in the heating or the like for homogenization or during subsequent hot rolling, these The intermetallic compound serves as a crack generation site during the embossing process to facilitate the generation of cracks. Particularly, when the Si content exceeds 0.3%, the cracking resistance during the embossing process is significantly reduced. Resulting in. Therefore, the amount of Si is limited to 0.3% or less.

In addition to the above-mentioned elements, Cu and M are added as necessary to improve the strength and to refine the crystal grains during recrystallization.
One or more selected from n and Cr may be added. If Cu, Mn, and Cr are all less than 0.06%, the above-mentioned effects are small. On the other hand, if each of them exceeds 0.3%, the crack resistance during embossing is reduced. Therefore, if necessary, Cu, Mn, C
When one or more kinds of r are added, the amount added is 0.1.
It was in the range of 06-0.3%.

Other than the above elements, Al and unavoidable impurities may be basically used. Here, if the unavoidable impurities other than Fe and Si are each 0.05% or less, there is little possibility that the performance of the aluminum alloy for embossing is particularly deteriorated.

In a general aluminum alloy,
A small amount of Ti may be added alone, or a small amount of Ti may be added in combination with a small amount of B, in order to refine the crystal grain of the ingot. It is permissible to add Ti alone or in combination with B for miniaturization. Where Ti
If the amount exceeds 0.2%, or if the B amount exceeds 0.04%, not only the above-mentioned effect is saturated, but also coarse particles are generated and the crack resistance during embossing is impaired. , Ti content is preferably regulated to 0.2% or less, and B content is regulated to 0.04% or less.

In addition, Be is often added to the Al-Mg based alloy in order to prevent the oxidation of the molten metal. However, the present alloy may contain 0.01% or less of Be.

Further, in the aluminum alloy sheet for embossing of the present invention, it is necessary that the average crystal grain size is not more than 60 μm. If the average crystal grain size exceeds 60 μm, the surface becomes rough and cracks are likely to occur during embossing. Therefore, in order to obtain a plate having excellent crack resistance at the time of embossing, the average crystal grain size is restricted to 60 μm or less. In the production of the aluminum alloy sheet of the present invention, since the final annealing is performed after cold rolling to obtain a soft material (O material) as described later, the average crystal grain size after the final annealing is set to 60 μm or less. is necessary.

Next, a method of manufacturing the aluminum alloy sheet for embossing according to the present invention will be described.

First, a molten aluminum alloy having the above-described composition is cast according to a conventional method. As a casting method, a semi-continuous casting method (DC casting method) is generally used, but a thin sheet continuous casting method (continuous casting rolling method) may be applied from the viewpoint of energy saving and cost saving. For the obtained ingot,
Homogenization, hot rolling, and cold rolling are performed in that order.
The thickness of the product is about 25 to 2.0 mm, and final annealing is performed to finish it as a soft material (O material).

Here, the homogenization treatment for the ingot is effective for refining the recrystallized grains at the time of final annealing and improving the formability, and at a temperature in the range of 450 to 580 ° C., 1 to 24.
It is preferable to set the heating conditions for time. Although hot rolling is performed after the homogenization treatment, hot rolling may be performed again after performing ingot heating after the homogenization treatment, or hot rolling may be started immediately after the homogenization treatment, In any case, the hot rolling start temperature is preferably in the range of 400 to 530 ° C.

After the completion of the hot rolling, cold rolling is performed to obtain a required product thickness. Here, intermediate annealing may be performed before cold rolling as needed, or intermediate annealing may be performed as needed in the middle of cold rolling. In this case, the intermediate annealing may be batch annealing or continuous annealing. In the case of batch annealing, it is preferable to set the condition to 280 to 400 ° C. × 0.5 to 5 hours.
It is preferable that no holding is performed at 0 to 550 ° C., or holding is performed for 3 minutes or less.

After cold rolling, the sheet is recrystallized to obtain a soft sheet (O) having a recrystallized structure having an average crystal grain size of 60 μm or less.
The final annealing is performed to obtain a material. The temperature of the final annealing is preferably in the range of 280 to 560 ° C. If the annealing temperature is lower than 280 ° C., it is difficult to sufficiently recrystallize. On the other hand, if the temperature exceeds 560 ° C., the surface is oxidized so strongly that the surface is discolored and the recrystallized grains may become coarse. In this final annealing, the average heating rate is several deg.
Even with batch annealing at tens of degrees Celsius / h, average heating rate is several degrees Celsius
/ Sec to several tens of degrees Celsius / sec. In the case of batch annealing, the heating and holding time at a temperature of 280 to 560 ° C is preferably 0.5 to 5 hours. In the case of continuous annealing, the annealing temperature is preferably set to 350 ° C. or higher (560 ° C. or lower), and may not be held after reaching the annealing temperature, or may be held for 3 minutes or less.

Here, as described above, the crystal grain size after final annealing needs to be 60 μm or less.
Final cold rolling rate before final annealing (cold rolling rate when cold rolling is performed once without interposing intermediate annealing, or secondary rolling after intermediate annealing when performing cold rolling with intermediate annealing interposed) (Cold rolling ratio) is preferably 40% or more.

The aluminum alloy sheet which has become a soft material by the final annealing as described above may be subjected to embossing as it is. However, when it is used for a building material such as a siding material, it imparts corrosion resistance and aesthetic appearance. For this reason, it is common practice to perform painting before embossing. The type of coating film is not particularly limited,
Generally, a fluorine resin film, an epoxy resin film, an acrylic resin film, a polyester resin film, or the like, or a combination of two or more layers is used. The thickness of such a coating resin film is generally about 5 to 30 μm.

The plate (painted plate) thus coated is subjected to an embossing process. This embossing process is generally performed as it is without using a lubricant. Note that roll forming may be performed after the embossing process.

[0034]

EXAMPLE Alloy No. 1 in Table 1 was used. 1 to No. Various alloys shown in No. 15 were melted according to a conventional method, and cast by a DC casting method. The obtained ingot was subjected to homogenization treatment-hot rolling-cold rolling-final annealing under various conditions as shown in production process codes A to E in Table 2 to finally obtain a sheet thickness of 0.4 m.
m aluminum alloy plate of O material. In the case of the production process codes A and B, the cold rolling was performed without intermediate annealing, and in the case of the production process codes CE, the intermediate annealing was performed at an intermediate plate thickness by batch annealing.

The average crystal grain size and the tensile strength of the obtained aluminum alloy sheet O were examined, and the results are shown in Table 3. Here, the average crystal grain size was determined by a cutting method.

Further, each aluminum alloy plate O material was subjected to a chemical conversion treatment in accordance with a conventional method, and then a polyester resin was coated on the front side with a thickness of 5 μm, and a 20 μm thick fluorine-based resin was further coated thereon. The back surface was coated with an epoxy resin of 5 μm. Thereafter, a rock-surface-like uneven pattern having a maximum height of about 2 mm was formed using an embossing roll. In addition, this pattern made width 500mm and length 650mm one pattern, and formed this pattern continuously. The plate thus continuously embossed was cut into a length of 2500 mm, the stiffness was examined, and the crack resistance in the embossing was examined. The results are shown in Table 3. Also shown. Here, regarding the strength of the waist, the tensile strength is 130 N / mm.
If it is ² or more, it has been found that there is no problem in handling, etc.
X / mm ² . Regarding the cracking resistance in the embossing process, intense light was applied from the surface side in a dark room, and one pattern having a width of 500 mm and a length of 650 mm was observed, and the number of locations where light leaked due to cracking was counted. When there were no cracks, the test was marked with "O" as a pass. When even one crack was found, the test was marked as "Fail" with a "X".

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

In Tables 1 to 3, the sample No. 1A, 2
The aluminum alloy sheets of A, 3A, 4C, 5C, 5E, and 6A all have the component composition satisfying the range specified in the present invention and the average crystal grain size satisfying the condition of 60 μm or less. In this case, the crack resistance in the embossing process is good, no cracks are generated, and the strength is 13
At 0 N / mm ² or more, it was found to have a stiffness that does not cause any practical problems.

On the other hand, the sample No. The composition of the 1D plate is within the range specified in the present invention, but the final cold rolling reduction is low, so the crystal grain size is large, the strength is low, the stiffness is low, and at the same time, cracks occur in the embossing process. have done. Sample No. Although the composition of the 5D plate was within the range of the present invention, the crystal grain size was large due to the low final cold rolling reduction, and cracks occurred during embossing. However, in this case, since the Mg content of the alloy was relatively large, the strength and stiffness were not particularly problematic.

Further, the sample No. The plate of 7B uses a 3003 alloy as a conventional material. In this case, no crack is generated in the embossing process, but the strength is low and the stiffness is low. Sample No. The plate of 8B is an example using a 3004 alloy as a conventional material. In this case, there is no problem in strength and stiffness, but cracks occurred in the embossing process.

Further, the sample No. The 9A plate used a comparative alloy having a low Mg content, but in this case, the strength was low and the stiffness was insufficient, and cracks occurred during embossing. On the other hand, sample No. 10A, 11A, 12
A, 13A, 14A, and 15A are made of Si, F, respectively.
e, Mn, Cr, using a comparative alloy containing excessive amounts of Cu, in these cases the strength was sufficient,
Cracks occurred during embossing.

[0044]

As is clear from the above embodiments, the aluminum alloy sheet for embossing according to the present invention is less likely to crack during embossing, has excellent crack resistance, and has high strength. Is moderately high and the stiffness of the board is strong, so that it can be used as a board material for embossing mainly used for building materials such as siding materials, and can sufficiently cope with thinning.

Claims (4)

[Claims] 1. An alloy containing 1.2 to 2.1% of Mg (mass%, the same applies hereinafter), is restricted to 0.3% or less of Si and 0.3% or less of Fe, and the remainder is Al and inevitable. An aluminum alloy sheet for embossing, having excellent resistance to cracks in embossing, characterized by being made of a soft material comprising a metallic impurity and having an average crystal grain size of 60 μm or less. 2. A composition containing 1.2 to 2.1% of Mg and containing C
u 0.06-0.3%, Mn 0.06-0.3%, Cr
It contains one or more of 0.06 to 0.3%, and is further restricted to 0.3% or less of Si and 0.3% or less of Fe, with the balance being less than Al and unavoidable impurities. An aluminum alloy sheet for embossing with excellent embossing crack resistance, characterized by being made of a soft material having an average crystal grain size of 60 μm or less. 3. An alloy containing 1.2 to 2.1% of Mg and containing
i is controlled to 0.3% or less and Fe is controlled to 0.3% or less, and the balance is made of Al and unavoidable impurities, and the surface of a soft material having an average crystal grain size of 60 μm or less is coated. An aluminum alloy coated plate for embossing processing. 4. A composition containing 1.2 to 2.1% of Mg and containing C
u 0.06-0.3%, Mn 0.06-0.3%, Cr
One or two or more of 0.06 to 0.3% are contained, Si is regulated to 0.3% or less, Fe is regulated to 0.3% or less, respectively, and the balance is less than Al and unavoidable impurities. An aluminum alloy coated plate for embossing, wherein a surface of a soft material having an average crystal grain size of 60 μm or less is coated.