JP2003226926A - Aluminum alloy sheet having excellent bending workability and production method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an Al-Mg-Si alloy sheet which has excellent bending workability such as flat hemming in particular, and further has the other properties required for a panel, and to provide a production method thereof. <P>SOLUTION: The Al-Mg-Si aluminum alloy sheet comprising 0.4 to 1.3% Si, 0.2 to 1.2% Mg, 0.01 to 0.65% Mn, and 0.001 to 1.0% Cu, and the balance Al with inevitable impurities. The ratio of the integrated intensity in the ä200} plane in the surface of the aluminum alloy sheet is ≥50%, and the ratio of the total integrated intensity in the ä200} plane and the ä400} plane is ≥60%. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al-Mg-Si based aluminum alloy plate (hereinafter, aluminum is simply referred to as Al) having excellent bending workability such as hemming and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, it has been excellent in moldability (hereinafter simply referred to as "formability") for transportation vehicles such as automobiles, ships or vehicles, home electric appliances, construction and structural members.
5000-series (satisfying the standard) of Al-Mg-based AA to JIS or Al-Mg-Si-based AA to JIS 6000-series with excellent moldability and bake hardenability (hereinafter referred to simply as 5000-series) To 6000 series) Al alloy materials (generally referred to as rolled aluminum, extruded shapes, forged materials, and other wrought aluminum alloy materials) are used.

In recent years, in response to global environmental problems caused by exhaust gas and the like, improvement in fuel consumption has been pursued by reducing the weight of vehicle bodies of transportation machines such as automobiles. For this reason, in particular, the application of lighter Al alloy materials to the body of automobiles is increasing in place of the steel materials that have been conventionally used.

Among these Al alloy materials, automobile hoods,
For panels such as outer panels (outer plates) and inner panels (inner plates) of panel structures such as fenders, doors, roofs, and trunk lids, a thin, high-strength Al alloy plate is used as an excess Si type 6000 series. The use of Al alloy plates is being considered.

This excess Si type 6000 series Al alloy basically contains Si and Mg as essential elements, and Si / Mg is 1 in mass ratio.
The above is an Al-Mg-Si based aluminum alloy. And since this excess Si type 6000 series Al alloy has excellent age hardening ability, it secures formability by low yield strength during press forming and bending, and artificial aging such as baking coating treatment after forming. There is an advantage that the required strength can be secured by age hardening by heat treatment and improving the yield strength.

Further, these excess Si type 6000 series Al alloy materials are
Compared to other 5000 series Al alloys, which have a large amount of alloys such as Mg, the amount of alloying elements is relatively small. Because of this, these 60
When the scrap of 00 series Al alloy material is reused as the Al alloy melting material (melting raw material), the original 6000 series Al alloy ingot is easily obtained and the recyclability is excellent.

On the other hand, in the outer panel of the automobile, etc., an Al alloy plate is press-formed such as bulging, drawing or trim to form an outer panel, and then the edge of the outer panel is bent (turned back 180 degrees) to form the inner panel edge. The joint is subjected to a severe bending process called heme (also called hemming) process. Further, severe press forming such as deep drawing is combined and applied to the inner panel.

In particular, as an outer panel application,
It is also required to combine high strength (high age hardening), high corrosion resistance, and high weldability.

The hem processing of the outer panel is performed by a down-flange step of bending the edge of the outer panel to an angle close to 90 ° with a tool such as a punch, and a prehem step of further bending the edge of the outer panel inward to about 135 °.
It is performed by a flat hem process or a rope hem process.

In the flat hem process and the rope hem process, as shown in FIG. 1, the end of the inner panel 2 is housed (inserted) in the bent portion A of the outer panel 1, and the edge 1c of the outer panel 1 is further rotated by 180 ° with a tool. Bend inward to form a hem. Of these, in the flat hem,
The edge of the inner panel 2 and the flat hem portion (180-degree bent portion) A of the outer panel 1 come into contact with each other, and the two end portions are joined together and brought into close contact with each other to have a flat bent portion shape. On the other hand, the rope hem has a rope-shaped cross-sectional shape in which the bent portion bulges in an arc shape,
The appearance is not good as compared with the flat hem shape. In addition, there is a problem that the contact area between the outer panel and the inner panel is small and the bondability and adhesion are poor.

For this reason, particularly in automobile parts and the like where appearance and aesthetics are important, the final process of hem processing is usually performed by a flat hem process, which is a severe bending process.

[0012] However, the flat hem shape is much more difficult to machine than the rope hem shape because of the flat bent portion shape. Therefore, in flat hem processing of an Al alloy sheet, the edge bend (hem section, bent section) A of the flat hem that is formed, as compared to conventional steel sheets, is as shown in Fig. 1 in order. Defects such as rough skin X, minute cracks Y, and relatively large cracks Z tend to occur. When such a defect occurs, the outer panel cannot be applied.

In contrast to the flat hem processing of such an Al alloy plate, conventionally, the flat hem processing is performed by preventing the occurrence of a defect in the edge bending portion A on the flat hem processing step side or the material side of the Al alloy plate. Various techniques for improving the property have been proposed.

From the flat hem processing side, for example,
In flat hem processing of a high-strength Al alloy plate of about 186 MPa, the bending radius Rd (shoulder radius of the die) of the flange corner formed on the outer panel is 0.8t to 1.8t (where t is Al It is proposed to prevent the above defects from occurring by increasing the thickness of the alloy plate) (see Patent Document 1). Further, improvement of the processing method itself, such as performing flat hem processing with a roller hem, has been proposed.

[0015]

[Patent Document 1] Japanese Patent Publication No. 63-2690

On the other hand, various proposals and proposals have been made from the raw material side to improve the flat hem workability by controlling the grain boundary precipitates of the Al alloy plate or lowering the proof stress itself of the Al alloy plate to 140 MPa or less. There is.

[0017]

However, the flat hem processing conditions have tended to become more difficult in recent years. The reason is that the shape (design) of the flat-hem processed part of the outer panel is complicated. When the edge contour shape of the outer panel to be flat-hem processed is not a linear simple shape A as shown in Fig. 2 but a complicated shape with an arc shape B or a corner C, The defects are more likely to occur.

The reason for this is that the Al alloy plates for the outer panel and the inner panel have become thinner in recent years to a plate thickness of 1.0 mm or less in order to reduce the weight of the panels. For example, Al alloy plates for outer panels have a thickness of 1.0 mm or less, 0.8 to 0.9 mm, and so on. Al alloy sheets for inner panels also have a thickness of 1.0 mm or less, 0.5 to 0.8 mm, and so on. In these thinned Al alloy plates, the thinner the plate thickness of the inner panel inserted in the curved edge of the outer panel, the more stringent the bending conditions become and the more difficult the flat hem processing becomes. This tendency becomes remarkable in the thinned Al alloy plate described above.

In flat hem processing, a slight gap x is inevitably formed between the end 2a of the inner panel 2 inserted into the curved edge A of the outer panel 1 and the inner surface Aa of the curved edge A. Is processed in the state. This gap x is the ratio (x / l) to the flange length (perimeter of hem edge A) l shown in Fig. 1.
With this, it is generally 0.6 or less, although it depends on the processing conditions. However, if there is this gap x or if this gap x becomes large, the thickness of the edge bend portion A (bending portion) of the outer panel 1 becomes thin, and the bending conditions become strict, so cracks Z
And other defects are likely to occur.

For such a severe flat hem processing of an Al alloy plate, there are cases where the above-mentioned conventional improvement techniques on the side of the flat hem processing and on the side of the material of the Al alloy plate are not always sufficient. Further, the improvement of the flat hem processing may rather contradict the other characteristics of the Al alloy plate. For example, when the flat hem workability is improved by lowering the yield strength of the Al alloy plate itself, the press formability is lowered, or even with an excess Si type 6000 series Al alloy plate, the panel coating baking step after plate forming After the artificial age hardening treatment at a low temperature in a short time using such as, the yield strength is insufficient, and problems such as insufficient dent resistance occur.

The present invention has been made by paying attention to such a situation, and its purpose is to improve the bending workability of flat hem and the like, and also to satisfy other panel required characteristics.
An object of the present invention is to provide a g-Si based Al alloy plate and a manufacturing method thereof.

[0022]

In order to achieve this object, the gist of the aluminum alloy sheet of the present invention is Si: 0.4 to 1.3.
%, Mg: 0.2 to 1.2%, Mn: 0.01 to 0.65%, Cu: 0.001 to 1.0%
Al-Mg-Si containing Al and the balance Al and unavoidable impurities
System aluminum alloy plate, the ratio of the integrated strength of the {200} plane on the surface of the aluminum alloy plate is 50% or more, and the ratio of the total integrated strength of the {200} plane and the {400} plane is 60% or more. Suppose there is.

Similarly, in order to achieve this object, the gist of the method for producing an aluminum alloy sheet of the present invention is S
i: 0.4 to 1.3%, Mg: 0.2 to 1.2%, Mn: 0.01 to 0.65%, Cu: 0.
After cold rolling an Al-Mg-Si aluminum alloy sheet containing 001 to 1.0% at a rolling reduction of 60% or more, it is annealed at a temperature of 350 ° C or less if necessary, and heat treatment including solution treatment and quenching is performed. Treated to make the ratio of integrated strength of {200} plane on the surface of aluminum alloy plate 50% or more, and the ratio of total integrated strength of {200} plane and {400} plane 60% or more, and conductivity. Is 43 to 47 IACS% and the crystal grain size is 50 μm or less.

The Al alloy plate referred to in the present invention is a plate that has been subjected to tempering treatment (heat treatment) after cold rolling and aged at room temperature, and is a forming material before press forming or bending. It refers to a board. Therefore, each of the above requirements is also a state of the Al alloy plate after the heat treatment, and from a short period of time after the heat treatment to an arbitrary period from press forming and / or bending such as flat hem It refers to the state of an Al alloy plate that has been aged at room temperature, regardless of the long term. Also,
The term "tempering treatment" as used herein refers to various tempering treatments such as a solution heat treatment and a quenching treatment, a subsequent pre-aging treatment described later, and an aging treatment which is performed if necessary.

The present inventors have found that the flat hem machinability is
The relationship with the structure of the Al-Mg-Si system Al alloy plate was examined again. As a result, the cube orientation of the crystal grains of the Al-Mg-Si system Al alloy plate (ratio of integrated intensity of {200} plane and total integrated intensity of {200} plane and {400} plane) is flat hem. It was found that there is a close correlation with workability. That is, the flat hem processability is improved as the proportion of the crystal grains having the cube orientation increases. On the other hand, the smaller the proportion of the crystal grains having the cube orientation, the lower the flat hem processability.

In the field of Al alloy plates, controlling the proportion of crystal grains having a cube orientation is known per se. For example, in an Al alloy foil for pure Al-based electrolytic capacitor electrodes, in order to increase the etching pits and improve the electrode characteristics, the {200} plane (crystal grains with cubic orientation)
A technique for controlling the ratio of the integrated intensity of is disclosed in Japanese Patent Publication No. 1-33546 and Japanese Patent Laid-Open No. 6-287723. Also,
In order to improve bending workability in press forming of 5000 series Al alloy plate with a large amount of Mg, {100} plane and {110} plane
A technique for setting the integrated intensity ratio with respect to the surface to be 1 or more is disclosed in Japanese Laid-Open Patent Publication No.
It is disclosed in Japanese Patent No. 6, etc.

However, in the case of the Al alloy foil, the purpose is to improve the electrode characteristics described above, and the purpose is completely different from the present invention. Further, in the case of the 5000 series Al alloy plate, although the purpose is similar to the present invention, in order to enhance the ultimate deformability, {10
The integrated intensity ratio between the 0} plane and the {110} plane is set to 1 or more. However, in the 6000 series Al alloy plate targeted by the present invention, flat hem processing is performed even if the integrated intensity ratio of the {100} plane and the {110} plane is 1 or more, as in Japanese Patent Laid-Open No. 10-8176. Sex cannot be improved. The reason for this is that the 6000 series Al alloy plate is inferior in flat hem processability and press formability to the 5000 series Al alloy plate, and the flat hem process conditions intended in the present invention are the same as those of the press form intended in the above publication. This is because the processing conditions are more severe than those for bending at the time.

As will be described later, an ordinary Al-Mg-Si-based Al alloy plate obtained by a conventional method has a small proportion of crystal grains having a cube orientation. In other words, in order to obtain an Al alloy plate structure in which crystal grains having a cube orientation are present in a specific amount as in the present invention, it is necessary to add special steps or process conditions as in the manufacturing method described later. .

However, in the present invention, the production of the Al alloy plate does not become complicated and the production cost does not significantly increase even by the above-mentioned special production process. Therefore, this point is also an advantage of the present invention.

According to the present invention, as in the conventional case, it is possible to obtain
Even if the 2% proof stress is not set to a low strength of 140 MPa or less, it is particularly excellent in hem processability such as flat hem and press formability. As a result, the 0.2% proof stress of the Al alloy plate can be increased to a high strength of 140 MPa or higher.
A high-strength panel exceeding 180 MPa can be obtained even by low-temperature artificial age hardening treatment at ℃ × 20 minutes.

Further, since the Al alloy sheet of the present invention has the above effects, it is an outer panel having a plate thickness of 0.5 mm or more, which is particularly severe in bending, and has a plate thickness of 1.3 mm or less to 1.0 mm. It is preferably applied when hemmed to the following thin inner panel. Similarly, the Al alloy sheet of the present invention is preferably applied to flat hem processing which is a severe bending condition among bending processing. Further, the Al alloy sheet of the present invention is widely used for flat hem processing, and is suitable for being applied to an outer panel of an automobile, which is particularly required for flat hem processing.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION First, the requirements for the structure of the Al alloy sheet of the present invention will be described below. In the following description, the flat hem processing, which is a severe bending condition among the bending processes, is mainly performed. However, if the flat hem processing is improved, other hem processability and other bend processability are also improved.

In the present invention, in order to improve the bending workability of flat hem or the like, the ratio of the integrated intensity of the {200} plane of the Al alloy plate surface by X-ray diffraction is 50 with respect to the cube orientation of the Al alloy plate crystal grains. % And above {200} face and {400
The ratio of the total integrated intensity by X-ray diffraction with respect to the} plane is specified to be 60% or more.

The ratio of the integrated intensity of the {200} plane by X-ray diffraction is less than 50%, or the X of the {200} plane and the {400} plane is X.
When the ratio of the total integrated intensity by line diffraction is less than 60%, there is no great difference from the crystal grain structure of the conventional Al alloy plate, and there is particularly no effect of improving bendability such as flat hem. Therefore, the workability of the Al alloy plate is remarkably deteriorated in the flat hem processing under the severe conditions described above.

On the other hand, the ratio of the integrated intensity of the {200} plane is 80%.
If the ratio exceeds 90%, or if the ratio of the total integrated strength of the {200} face and the {400} face exceeds 90%, the press formability of the Al alloy sheet such as bulging and drawing can be reduced. There is a nature. As a result, in press molding, there is a possibility that shape accuracy or shape fixability, which is important particularly as an outer panel, may be significantly reduced. Therefore, in order to prevent deterioration of other properties such as press formability other than hemmability,
The ratio of the crystal grains having the cube orientation is such that the ratio of the integrated strength of the {200} plane on the Al alloy plate surface is in the range of 50 to 80% and the total integrated strength of the {200} and {400} planes is The ratio is preferably in the range of 60% to 90%.

Regarding the relationship between the bending direction of the plate in a flat hem and the cube orientation of the plate (disposition direction), the cube orientation of the plate should be parallel to the bending direction of the plate (the bending direction of the plate. Even if it is bent (with the plate parallel to the rolling direction of the plate), the cube direction of the plate is bent at right angles to the bending direction of the plate (the bending direction of the plate is perpendicular to the rolling direction of the plate) Also in this case, good flat hem machinability can be obtained. There is no distinction between 0 degree and 90 degree because the cube orientation of the panel has the same structure even if rotated 90 degrees. Therefore, even if the bending direction of the plate is parallel to or perpendicular to the rolling direction of the material plate, the cube orientation has the same structure, and good flat hem processability can be obtained. However, in the relationship between the plate bending direction other than the above two directions and the plate cube direction (arrangement direction), such as the plate cube direction being 45 ° with the plate bending direction, the bending of flat hem etc. Since the workability may be poor, it is preferable that the bending direction of the plate in bending is the above two directions.

In the present invention, the degree of cube orientation development of crystal grains of an Al alloy plate is measured by an X-ray diffractometer (for example,
Rigaku RAD-RC etc.) is used to measure the surface of the Al alloy plate without any pretreatment. A non-oriented Al sample was used as the standard sample, and {111} for this standard sample.
Plane, {200} plane, {220} plane, {311} plane, {222}
Plane, {400} plane, {331} plane, {420} plane, {422}
Calculate the total sum A of the integrated intensities of the surfaces and. And this
Ratio (%) of the integrated intensity I ₁ of the {200} plane to A, {2
Ratio (%) of total integrated intensity I ₂ of the 00} plane and the {400} plane
, Is the ratio (%) of each integrated intensity.

Further, in the present invention, it is preferable that the electric conductivity of the surface of the Al alloy plate is in the range of 43 to 47 IACS%. By setting this conductivity range, the amount of compound phase such as GP zone formed during artificial aging treatment such as panel coating baking process is secured, and it corresponds to press molding and coating baking process, for example, after 2% stretch. It is guaranteed that the required strength of 170 MPa or more will be obtained during low temperature artificial aging treatment at 170 ℃ × 20 minutes. The Al alloy plate whose conductivity is to be measured is 0.05 to 0.1 m.
m After mechanical polishing, electrolytically etch and measure the conductivity of the surface.

When the conductivity exceeds the above 47 IACS%,
Flat hem processability may be reduced. In addition, the press formability may decrease. Therefore, the upper limit of the conductivity is preferably specified as 47 IACS%.

On the other hand, when the conductivity is less than 43 IACS%,
The amount of the compound phase such as GP zone formed during the artificial aging treatment may be reduced. Therefore, the artificial aging hardening ability is lowered, and in particular, the proof stress (σ _0.2 ) of 170 MPa or more may not be obtained by the artificial aging treatment at a low temperature for a short time. Therefore, even if the plate thickness is 1.0 mm or less, the lower limit of conductivity should be specified as 43 IACS% in order to guarantee rigidity and strength such as dent resistance as a panel outer plate for automobiles. Is preferred.

In the present invention, the crystal grain size of the Al alloy plate is also changed.
It is preferably specified to be 50 μm or less. By making the crystal grain size fine or small within this range, flat hem processability and press formability are secured or improved. If the crystal grain size becomes coarser than 50 μm, the flat hem processability and press formability will be significantly reduced, such as defects such as cracks in the flat hem and orange peel defects when panelizing by press forming. It is easy for rough skin to occur.

The grain size referred to here is the rolling of the plate.
It is the average diameter of the crystal grains in the (L) direction. This crystal grain size is
The surface of the alloy plate that had been mechanically polished by 0.05 to 0.1 mm and then electrolytically etched was observed using an optical microscope.
It is measured by the line intercept method. The length of one measurement line was 0.95 mm, and the total length of measurement lines was set to 0.95 × 15 mm by observing a total of 5 fields of view with 3 lines per field of view.

Next, an embodiment of the chemical composition of the Al alloy sheet of the present invention will be described below. The basic composition of the Al alloy sheet of the present invention is S in order to secure the above-mentioned structure regulations and various characteristics.
i: 0.4 to 1.3%, Mg: 0.2 to 1.2%, Mn: 0.01 to 0.65%, Cu: 0.
Al-Mg-Si (6000 series) Al alloy containing 001 to 1.0% and the balance Al and unavoidable impurities. In the present invention, all the percentages of chemical composition, including the percentages in the claims, mean mass%.

Other than the above alloying elements, Cr, Zr, Ti,
Other alloying elements such as B 2, Fe, Zn, Ni and V are basically impurity elements. However, from the viewpoint of recycling, as a melting material, not only high-purity Al ingots, but also 6000 series alloys and other Al alloy scrap materials, low-purity Al ingots, etc. are used as melting raw materials, In the case of smelting, these other alloying elements are inevitably included. Therefore, the present invention permits the inclusion of these other alloying elements within a range that does not impair the intended effect of the present invention.

The content range and meaning of each element, or the allowable amount will be described below. Si: 0.4 to 1.3%. Si, together with Mg, solid solution strengthening, during artificial aging treatment at the low temperature such as paint baking treatment, forms a compound phase such as GP zone, exerts age hardening ability, and is required as an outer panel of an automobile, for example, It is an essential element for obtaining the required strength of 170 MPa or more. Therefore, the present invention excess Si type
It is the most important element in 6000 series Al alloy sheet to combine various properties such as press formability and hemmability.

Further, in order to exert an excellent low temperature age hardening ability of 170 MPa or more after the low temperature paint baking treatment after molding on the panel (at the time of low temperature aging treatment of 170 ° C. × 20 minutes after application of 2% stretch) In addition, the Si / Mg mass ratio was 1.0 or more, and the excess Si type 6000 series Al containing Si in excess of Mg was used.
The alloy composition is preferable.

When the amount of Si is less than 0.4%, it is impossible to combine the above-mentioned age hardening ability and various characteristics required for each application such as press formability and heme processability. On the other hand, Si is 1.
If the content exceeds 3%, heme workability and press formability are particularly impaired. Furthermore, the weldability is significantly impaired. Therefore, Si is in the range of 0.4 to 1.3%. In addition,
In the outer panel, hemmability is especially important, so
In order to further improve the press-formability and the flat hem workability, the Si content is preferably set to a lower range of 0.6 to 1.2%.

Mg: 0.2-1.2%. Mg, solid solution strengthening, during the artificial aging treatment such as paint baking treatment, forms a compound phase such as GP zone together with Si, and exhibits age hardening ability, and as a panel, for example, 170M
It is an essential element for obtaining the required strength of Pa or higher.

When the content of Mg is less than 0.2%, the absolute amount is insufficient, so that the compound phase cannot be formed during the artificial aging treatment.
It cannot exhibit age hardening ability. Therefore, the required strength of 170 MPa or more required for the panel cannot be obtained.

On the other hand, if the Mg content exceeds 1.2%, the moldability such as press moldability and bending workability is rather impaired. Therefore, the content of Mg is in the range of 0.2 to 1.2%, and the amount of Si / Mg is 1.0 or more by mass ratio. Further, in order to further improve the flat heme workability, when the Si content is set to a lower range of 0.6 to 1.2%, in order to correspond to this, in order to obtain an excessive Si type 6000 series Al alloy composition , Mg content is also preferably in a lower range of 0.2 to 0.7%.

Cu: 0.001 to 1.0% Cu has the effect of promoting GPII and β "phase precipitation in the crystal grains of the Al alloy material structure under the conditions of artificial aging treatment at a relatively low temperature and a short time according to the present invention. In addition, Cu solid-solved in the aged condition
Also has the effect of improving moldability. This effect does not occur when the Cu content is less than 0.001%. On the other hand, if it exceeds 1.0%, the stress corrosion cracking resistance, the thread rust resistance of the corrosion resistance after coating, and the weldability are significantly deteriorated. Therefore, 0.8% or less in the case of structural material applications where corrosion resistance is important, and 0.1% or less in which the development of thread rust resistance becomes remarkable in the case of panel applications such as automotive exterior panels. Preferably.

Mn: 0.01 to 0.65% Mn produces dispersed particles (dispersed phase) during homogenization heat treatment, and these dispersed particles have an effect of hindering grain boundary migration after recrystallization. It has the effect of obtaining grains. As described above, the press formability and hemmability of the Al alloy sheet of the present invention are improved as the crystal grains of the Al alloy structure are finer. In this respect, if the Mn content is less than 0.01%, these effects are not obtained.

On the other hand, when the Mn content increases, dissolution,
Coarse Al-Fe-Si- (Mn, Cr, Zr) 3 -based intermetallic compounds and crystalline precipitates are likely to be formed during casting, which causes deterioration of the mechanical properties of the Al alloy sheet. In addition, especially in flat hem processing where the processing conditions became strict due to the complicated shape and thinning, or the presence of a gap between the inner panel edge and the outer panel edge curved part, the Mn content was 0.15%. If it exceeds the limit, the processability of the hem decreases. Therefore, Mn is 0.01
To 0.65%, and more preferably 0.01 to 0.15% in the flat hem processing where the above-mentioned processing conditions are severe.

Cr, Zr. Similar to Mn, these transition elements of Cr and Zr have an effect that dispersed particles (dispersed phase) are generated during homogenization heat treatment, and fine crystal grains can be obtained. However, Cr and Zr are each 0.15
If the content exceeds%, the hem processability is deteriorated particularly in the flat hem process in which the above processing conditions are severe. Therefore, it is preferable to regulate the Cr and Zr contents to 0.15% or less.

Ti, B. If Ti and B are contained in amounts exceeding Ti: 0.1% and B: 300 ppm, respectively, coarse crystallized substances are formed and formability is deteriorated. However, if Ti and B are contained in a small amount, they also have the effect of refining the crystal grains of the ingot and improving the press formability. Therefore, Ti: 0.1% or less and B: 300ppm or less are allowed.

Fe. Fe contained as an impurity by mixing from the melting raw material is Al
Crystallized substances such as ₇ Cu ₂ Fe, Al ₁₂ (Fe, Mn) ₃ Cu ₂ and (Fe, Mn) Al ₆ are formed. When 0.10% or more of Fe is contained, these crystallized substances serve as nuclei for recrystallized grains, prevent coarsening of the crystal grains, and serve as fine grains of 50 μm or less.
However, on the other hand, these crystallized substances markedly deteriorate the fracture toughness and fatigue properties, and further the flat heme processability and press formability in which the above-mentioned processing conditions are particularly severe. Since these deterioration characteristics become remarkable when the Fe content exceeds 0.50%, the Fe content (allowable amount) is 0.10 to 0.
It is preferably 50%.

Zn. If Zn is contained in excess of 0.5%, the corrosion resistance is significantly reduced. Therefore, the Zn content is preferably 0.5% or less, which is as small as possible.

The bending process intended for the Al alloy sheet of the present invention is as follows.
Especially intended for flat hem processing. However, the present invention
Since the Al alloy plate is excellent in flat hem workability, which is a severe condition, naturally it is also excellent in workability of the rope hem and the like and other bending workability, which are more lenient conditions. Therefore, not only flat hem but also hem processing such as other rope hem is targeted. In addition, other bending work is V bending,
The target is bending of commonly used plates such as U-bending and 90-degree bending.

The hem processing is not limited to the normal hem processing performed by the down-flange process, the pre-hem process, the flat hem or the rope hem process described above, and if the hem is finally formed, a roller hem, etc. We also target objects with different processes and process conditions as hemming,
Applicable.

As described above, the hem processing to which the present invention is applied is an outer panel having a plate thickness of 0.5 mm or more.
Thin inner panel with a thickness of 1.5 mm or less, especially 1.0 mm or less
It is preferable to be applied to severe hem processing for an Al alloy plate, particularly hem processing such as flat hem. If the thickness of the Al alloy plate as the outer panel is thinner than this and the thickness of the Al alloy inner panel is thicker than this, hemming becomes relatively easy.

It is to be noted that the hem processing such as the flat hem is carried out for all four peripheries of the Al alloy sheet of the present invention, or only for the selected side (side edge portion), and the hem processing is carried out. Whether the end shape of the outer panel to be formed is a linear shape, an arc shape, or a complicated shape having a corner is appropriately selected according to the member design of the outer panel and the like.

According to the present invention, as described above, the Al alloy sheet is excellent in hem workability such as flat hem and press formability, even if the 0.2% proof stress of the Al alloy plate is not made as low as 140 MPa or less as in the conventional case. As a result, the 0.2% proof stress of the Al alloy plate can be increased to a high strength exceeding 140 MPa, and even with low temperature artificial age hardening treatment at 170 ℃ × 20 minutes in the coating process after molding, 180 M
It is possible to obtain a high-strength panel that exceeds Pa.
However, when such high strength is not required, the proof stress of the Al alloy plate to be hemmed may be in the range of 110 to 140 MPa.

(Manufacturing Method) A method for manufacturing the above Al alloy sheet of the present invention will be described. As described above, in order to obtain the Al alloy sheet structure of the present invention in which the crystal grains having the cube orientation are present in a specific amount, the following cold rolling conditions in addition to the above-described component composition, and if necessary, after cold rolling, It is necessary to add special processes and process conditions such as annealing. In this respect, a normal Al alloy plate obtained by a conventional method has a small proportion of crystal grains having a cube orientation, and an Al alloy plate structure having a specific amount of crystal grains having a cube orientation cannot be obtained as in the present invention. .

In order to obtain the Al alloy sheet structure of the present invention in which a certain amount of crystal grains having a cube orientation are present, first, a sheet obtained by hot rolling or continuous casting rolling is subjected to a rolling reduction of 60% or more. Cold rolling with a high reduction rate. The reduction ratio in cold rolling
By setting the rolling reduction to a higher value of 60% or more, sufficient strain energy can be accumulated in the cold rolled sheet. As a result, it is possible to grow a specific amount of crystal grains having a cube orientation by annealing described later. When the reduction ratio in cold rolling is low, it does not change from the ordinary material, and in the annealing or solution treatment described below, there is a possibility that sufficient strain energy cannot be accumulated to grow a certain amount of crystal grains having a cube orientation. high. On the other hand, the higher the reduction rate in cold rolling, the more difficult the processing itself such as the occurrence of edge cracks. Therefore, the upper limit of the reduction rate is preferably about 95%.

Then, the cold-rolled sheet is optionally grown in order to grow a certain amount of crystal grains having a cube orientation.
At a temperature of 350 ° C or lower, preferably 200 to 300 ° C, for example,
It is preferable to anneal for 1 to 50 hours. By this annealing, fine recrystallized grains or sub-crystal grains having a cube orientation grow in a specific amount, the cubic orientation is easily developed in the final solution treatment, and the press formability and bending workability are significantly improved. If the annealing temperature is less than 200 ° C, this effect does not occur, and the ratio of the crystal grains having the cube orientation on the Al alloy panel surface is set to 50% or more for the integrated strength ratio of the {200} plane on the Al alloy plate surface. , The ratio of the total integrated intensity of the {200} plane and the {400} plane cannot be 60% or more. As a result, there is not much difference from the crystal grain structure of the conventional Al alloy plate, and there is no effect of improving the hem processability under the severe conditions, particularly flat hem.

On the other hand, when the annealing temperature exceeds 350 ° C., the crystal grains are likely to be coarsened, and roughening of the surface is likely to occur during press forming or hemming, and press formability such as bulging and drawing of an Al alloy plate is improved. Markedly reduced. This annealing can be performed using a batch furnace or a continuous annealing furnace.

Other process conditions can be used in a conventional manner, but there are also preferable conditions for improving the hem processability and other characteristics of the outer panel, such as flat hem, and will be described below.

First, in the melting and casting steps, an excess molten Al alloy melt, which has been melt-adjusted within the component specification range of the present invention, is subjected to a normal melt casting method such as a continuous casting rolling method or a semi-continuous casting method (DC casting method). Is appropriately selected and cast.

Then, after subjecting this Al alloy ingot to homogenization heat treatment, hot rolling and cold rolling at the above-mentioned high reduction ratio are carried out to process it into a plate shape such as a coil shape or a plate shape. that time,
If necessary, the above-mentioned annealing is also performed.

The processed Al alloy plate is first indispensably subjected to solution heat treatment and quenching as a heat treatment. Solution heat treatment and quenching are important steps for precipitating compound phases such as GP zone and β "phase into the grains sufficiently by artificial age hardening such as paint baking and hardening. It is preferable that the solution treatment condition is carried out in the temperature range of 500 to 540 ° C.

Conventionally, in the case of a panel for which flat heme processability is particularly important or under the severe flat heme process conditions, the solution treatment temperature is 500 to 500.
It was on the lower temperature side of 530 ℃. However, in the present invention,
As mentioned above, the 0.2% proof stress of Al alloy plate was
Even if it does not have a low strength of 0 MPa or less, it is particularly excellent in hem processability such as flat hem and press formability.

Therefore, the solution treatment temperature is set to 530 to 540 ° C.
In the high temperature side of the range, the 0.2% proof stress of the Al alloy plate is made to have a high strength exceeding 140 MPa, and the compound zones such as GP zone and β "phase are sufficiently grained by the artificial age hardening treatment of the panel after the subsequent plate forming. 180MPa even in the low temperature artificial age hardening treatment at 170 ℃ × 20 minutes in the painting process after molding.
It is preferable to make a high-strength panel that exceeds the above range.

During quenching after the solution treatment, the cooling rate is 50
It is preferable to perform rapid cooling at ℃ / minute or more. Cooling rate is 50
If the temperature is slower than ℃ / min, the strength after quenching will be low, and the age hardening ability will be insufficient, and the artificial aging treatment at a low temperature of 170 ℃ × 20 minutes, such as the paint bake hardening treatment afterwards, will give 170 MPa. The above high yield strength cannot be secured.

Further, Si, MgSi, etc. are likely to be deposited on the grain boundaries, which easily becomes a starting point of cracks during press molding and flat hem processing, and these moldability are deteriorated. In order to secure this cooling rate, the quenching treatment may be performed by air cooling using a fan or the like, but the cooling rate is likely to be slow, and it is preferable to perform the quenching treatment by selecting from water cooling means such as mist, spraying and dipping.

After the solution hardening treatment, it is preferable to carry out a pre-aging treatment in order to suppress the formation of clusters that cause room temperature aging. That is, 50 to 100 ° C, preferably 60
It is preferable to maintain the temperature in the range of to 90 ° C for the required time of 1 to 24 hours. The cooling rate after the preliminary aging treatment is 1
C./hr or less is preferable.

As the preliminary aging treatment, after the quenching completion temperature after the solution treatment is increased to 50 to 100 ° C., it is immediately reheated or kept as it is. Alternatively, after the solution treatment, quenching treatment up to room temperature and immediately reheating to 50 to 100 ° C. are performed.

In the case of continuous solution hardening treatment,
The quenching process is completed within the temperature range of the preliminary aging, and the coil is wound around the coil at the high temperature as it is. Note that the coil may be reheated before being wound on the coil, or may be kept warm after being wound. Further, after the quenching treatment up to room temperature, it may be reheated to the above temperature range and wound at a high temperature.

Furthermore, in order to suppress aging at room temperature, not only GPI is regulated but also GPII is positively generated,
After the pre-aging treatment, it is preferable to perform a sub-aging treatment at a relatively low temperature without a time delay to produce a more stable GPII and β "phase (mainly GPII). In this case, even after the pre-aging treatment, room temperature aging (natural aging) occurs over time, and after the room temperature aging occurs, the effect of the sub-aging treatment becomes difficult to be exerted.

In order to obtain these effects, in the above composition range of the Al alloy material, the aging treatment temperature is set to a sub-aging treatment range of 80 to 120 ° C., and the aging treatment time is required time, preferably 1 to 24 hours. It is preferable to set the range and to select the temperature and time from which the aging treatment effect can be obtained, depending on the composition. The cooling rate after the sub-aging treatment is preferably 1 ° C / hr or less. If the aging temperature is lower than 80 ° C and the holding time is too short, more stable GPII and β "phases cannot be generated. Therefore, the room temperature aging suppressing effect and the low temperature age hardening ability cannot be obtained.
On the other hand, at temperatures above 120 ° C, there is not much difference from normal aging treatment, GPII precipitates and aging proceeds too much, and strength becomes too high. This point is the same even if the holding time of the aging treatment is too long. The preliminary aging treatment temperature may be set to be as high as the aging treatment described later, and the heat treatment may be combined with or continuous with the aging treatment.

After the solution heat treatment and the quenching treatment, by using the pre-aging treatment and the sub-aging treatment in combination, the structure of the Al alloy material is made to have a GPII of little or no, that is, a stable GPI.
A microstructure composed of an I, β "phase and a supersaturated solid solution can be obtained. As described above, this microstructure has the excellent property that age hardening does not easily occur at room temperature. On the other hand, this microstructure is , 170 ℃ × 20 minutes low temperature age hardening treatment conditions, such as subsequent baking and heating
(Aging treatment) Even if the temperature is low, it also has an excellent property that it becomes a β "phase nucleation site and has a high low-temperature aging treatment ability.

In addition, it is of course possible to further increase the strength by performing an aging treatment or a stabilization treatment at a higher temperature depending on the use and the required characteristics.

[0082]

EXAMPLES Next, examples of the present invention will be described. Inventive Examples 1 to 5 in the composition range of the present invention and Comparative Examples 6 and 7 of each component composition deviating from the composition range of the present invention shown in Table 1, each 6000 series Al
In order to control the crystal orientation of the alloy sheet, as shown in Table 2, the reduction ratio of cold rolling and the annealing conditions and temperatures after cold rolling were changed to determine the integrated strength of the {200} plane on the Al alloy sheet surface. Various ratios and ratios of the total integrated strengths of the {200} surface and the {400} surface were changed to prepare Al alloy plates with a thickness of 1.0 mm.
Furthermore, the electrical conductivity and the crystal grain size were variously changed by changing the refining conditions.

The cold rolling conditions, the annealing conditions after the cold rolling, and the production of the Al alloy plate other than the solution heat treatment temperature were carried out by changing the thickness of the hot rolled plate for changing the reduction ratio of the cold rolling described below. Except that the same conditions were used. That is, 400 mm thick ingots in each composition range shown in Table 1 were melted by the DC casting method and then heated at 540 ° C.
× 4 hours of homogenization heat treatment, thickness at the end temperature 300 ℃
It was hot rolled to 2.3 to 8 mmt. This hot-rolled sheet was further cold-rolled with a thickness of 1.0 mm and a reduction rate of 55-80%.

These cold-rolled sheets were heat-treated under the same conditions as described below. First, after cutting each test piece size, it was put into an air furnace maintained at 570 ° C, and when each test piece reached the solution treatment temperature of 550 ° C (holding time 0 seconds), baked in 70 ° C hot water. It was put in. The cooling rate during the quenching treatment was 200 ° C / sec, the quenching end temperature (quenching temperature) was 70 ° C in common, and the pre-aging treatment was held at this temperature for 2 hours after quenching (cooling rate after holding 0.6 ° C. / hr). Table 2 shows these conditions. Note that only Invention Example 13 in Table 2 was quenched in water at room temperature and then not subjected to pre-aging treatment. Further, only Comparative Example 17 in Table 2 was subjected to solution treatment at 565 ° C with the holding temperature of the air furnace set to 570 ° C.
However, the other conditions were the same as above.

A plurality of test plates (blank) having a width of 50 mm and a length of 50 mm were cut out from these Al alloy plates, and the ratio of the integrated strength of the {200} plane on the surface of the Al alloy plate and the {200}
X is the ratio of the total integrated intensity of the {} plane and the {400} plane.
It was measured by a line diffraction measuring method. Further, the tensile strength (σ _B ), yield strength (σ _0.2 ) and elongation (%) after the heat treatment were measured. The results are shown in Table 2. Furthermore, taking into account the room temperature aging of the Al alloy plate, 4 months (120 days) after the above-mentioned heat treatment.
After room temperature aging, the electrical conductivity (IACS%) of each test plate, the crystal grain size, further, in the measurement conditions described below, parallel to the rolling direction, tensile strength (σ _B ), proof stress (σ _0.2 ), Elongation was measured. The results are shown in Table 3.

Further, in order to investigate the low-temperature aging treatment capacity, the test plate after room-temperature aging for 4 months after the above-mentioned tempering treatment was given a strain of 2% in advance and subjected to low-temperature artificial aging hardening treatment at 170 ° C. for 20 minutes. Then
The tensile strength (σ _B ), proof stress (σ _0.2 ) and elongation of each test plate were measured. These results are also shown in Table 3.

The tensile test was carried out according to JIS Z 2201, and the shape of the test piece was a JIS No. 5 test piece, so that the longitudinal direction of the test piece coincided with the rolling direction. Therefore, the tensile strength (σ _B ) and proof stress of each test plate
(σ _0.2 ) and elongation were measured in the L direction parallel to the rolling direction.
The crosshead speed was 5 mm / min, and the test was performed at a constant speed until the test piece broke.

Simulating that the aluminum alloy plate aged at room temperature is pressed or hem processed as an automobile panel,
The test plate after the room temperature aging was subjected to a molding test. More specifically, flat hem processing test, plane strain overhang height (LDH ₀ )
A test was conducted to evaluate the moldability. The results are shown in Table 3.

The flat hem processing test was as follows. For the blank (test plate after aging at room temperature),
First, we simulated the molding process of the outer panel of the car,
% Distortion is given in advance. Then, the flat hem processing allowance of the blank (the distance from the end of the outer panel blank after the hem processing that is bent inward to the end of the bent portion) is set to 12 mm, and the entire width direction of one longitudinal end is reduced. By the flange process, it was bent to an angle of 90 degrees. At this time, the shoulder radius Rd of the die is 0.8t (t is the plate thickness)
And Next, the edges of the blank were further folded inward by a prehem step to an angle of 135 °.

Then, simulating the flat hem processing conditions, an Al alloy plate for an inner panel having a plate thickness of 1 mm was blanked as described above.
It was inserted into the bent portion of the (outer panel), and flat hem processing was performed by bending the blank bent portion inward by 180 degrees. In addition, in these flat hem processing,
The blank was oriented such that its cube orientation was parallel to the bending direction of the flat hem and its longitudinal direction was coincident with the rolling direction of the plate.

Then, the surface condition such as rough skin, minute cracks, and large cracks was visually observed at the edge of the flat hem. The evaluation is 1; good with no rough skin or fine cracks, 2; no rough cracks, including small ones, 3; fine cracks, 4; large cracks, 5 ; Evaluated in 5 levels, from multiple to multiple large cracks. Good hem processability for this evaluation (usable)
It is judged to be 1 to 2 stages, and heme processability is inferior (unusable) for 3 or more stages.

Further, the conditions of the plane strain overhang height (LDH ₀ ) test are as follows: the test plate test piece having a width of 100 mm and a length of 180 mm after room temperature aging is used, and the longitudinal direction of the test piece is the direction perpendicular to the rolling direction. It was manufactured so as to agree with. And punch (ball head, 100m
m φ) and die (with beads)
The LDH ₀ value was defined as the lowest overhang height, which was performed three times under the conditions of ₀ kN, lubricating oil R-303, and molding speed of 20 mm / min. This LDH ₀ value is
30 mm or more for ○, 25 mm or more and less than 30 mm for △, 25
Those less than mm were evaluated as x.

The orange peel was evaluated by observing the surface of the molding material after the limiting drawing ratio test, and ◯ means that the skin did not become rough, and x means that the skin did.

Corrosion resistance test pieces after coating were sampled from the test plate after aging at room temperature, washed, and then subjected to zinc phosphate treatment and coating treatment under the same conditions. The zinc phosphate treatment was performed with a titanium phosphate colloidal dispersion, and then immersed in a zinc phosphate bath containing fluorine at a low concentration of 50 ppm to form a zinc phosphate film on the surface of the molding material. The coating process is a condition that is currently widely used after performing cationic electrodeposition coating.
It was painted at 170 ° C for 20 minutes.

Then, a thread rust resistance evaluation test was conducted on these coated test pieces. The results of these evaluations are also shown in Table 2. In the thread rust resistance evaluation test, a piece of 7 cm was cross-cut on the surface of the above-mentioned coated test piece, immersed in a 1.7% hydrochloric acid aqueous solution at 35 ° C for 2 minutes, and then at 40 ° C and 85% RH constant temperature and humidity. Left for 1500 hours in the atmosphere of
(Distance in the vertical direction from the cross cut, mm) was measured.
If the maximum length of this thread rust is 2.0 mm or less, it is ○, if it is 2.0 to 4.0 mm, it is △, and if it exceeds 4.0 mm, it is ×.
Evaluated as. The results are shown in Table 4.

As is apparent from Tables 1 to 4, {200} within the alloy composition range of the present invention and on the surface of the Al alloy plate
The ratio of the integrated intensity of the surface is in the range of 50-80%, and
The ratio of the total integrated intensity of the {200} plane and the {400} plane is 60%
Inventive Examples 1 to 13 in the range of up to 90% have excellent flat heme processability. The results of this example show that the flat hem processing under the severe conditions described above, such as the complicated shape of the hem processed portion of the outer panel and the thinning of the inner panel, can be sufficiently processed.

In this Example, the blank was bent so that its cube orientation was parallel to the bending direction of the flat hem (the longitudinal direction thereof was parallel to the rolling direction of the plate). Similarly, when bending ~ 13 so that its cube orientation is perpendicular to the bending direction of the flat hem (its longitudinal direction is perpendicular to the rolling direction of the plate), good flat hem processing is also performed. Sex was obtained.

On the other hand, even within the alloy composition range of the present invention,
Table 3 shows the ratio of the integrated intensity of the {200} plane and /
Alternatively, as shown in Table 4, in Comparative Examples 16 and 17 in which the ratio of the total integrated intensity of the {200} plane and the {400} plane is out of the range of the present invention, the flat hem machinability under the severe conditions is Remarkably lower than.

Among the invention examples, the invention examples in which the ratio of the integrated intensity of the {200} face and / or the ratio of the total integrated intensity of the {200} face and the {400} face shown in Table 3 are relatively low. As shown in Table 4, the flat hem processability of Nos. 6 and 9 is relatively low as compared with Invention Examples 1 and 2 having a relatively high ratio of integrated strength. Therefore, from the above results, the {20
The critical significance of the ratio of the integrated intensity of the 0} plane and / or the ratio of the total integrated intensity of the {200} plane and the {400} plane is supported.

Furthermore, invention examples 6 and 9 in which the ratio of the integrated intensity of the {200} plane and / or the ratio of the total integrated intensity of the {200} plane and the {400} plane are relatively low are as shown in Table 2. The cold rolling reduction is relatively low. Further, in Comparative Example 16 in which the ratio of these integrated strengths deviates relatively low, as shown in Table 2, the reduction ratio of cold rolling deviates relatively low. Therefore, from the above results, the cold rolling reduction condition for obtaining the ratio of the integrated strength of the {200} plane and / or the ratio of the total integrated strength of the {200} plane and the {400} plane of the present invention. Supports the critical significance of. In other words, it is necessary to add special conditions for cold rolling in order to obtain an Al alloy sheet structure in which a certain amount of crystal grains having a cube orientation are present as in the present invention.

Further, as is clear from Tables 1 to 4, except for Invention Example 12 in which the LDH ₀ is high and the crystal grain size is large, except for Invention Example 2 in which the ratio of the integrated strength is the highest in bulging. No orange peel is produced, and press moldability is excellent. Further, even with a low temperature artificial age hardening treatment of 170 ° C. × 20 minutes, the minimum required AB proof stress for outer panels of automobiles is 170 MPa or more, and it is also excellent in thread rust resistance.

However, among the invention examples, as shown in Table 3, 50
Inventive Example 12 having a crystal grain size exceeding μm and having a large crystal grain size, some orange peel occurs in the stretch forming. Also, 50 μm
In Comparative Example 17 in which the crystal grain size was larger than the above, LDH ₀ was low and orange peel was generated in the stretch forming. Therefore, the preferable significance of defining the crystal grain size is understood.

As described above, in the invention examples, the AB proof stress is 170 MPa or more even with the low temperature artificial age hardening treatment.
Inventive Example 13 having a conductivity as low as 40 IACS% as shown in Example 3 has a relatively low AB proof stress after the low temperature age hardening treatment. Therefore, the preferable meaning of the conductivity regulation can be understood.

Further, Comparative Examples 14 and 15 using the alloys of Comparative Examples 6 and 7 of Table 1 in which Si to Mg are out of the range of the present invention are relatively low,
Ratio of integrated intensity of {200} plane on Al alloy plate surface,
The ratio of the total integrated strength of the {200} plane and the {400} plane is within the range of the present invention, but the AB proof stress is less than 170 MPa by the low temperature artificial age hardening treatment at 170 ° C. for 20 minutes.

From the above results, the integrated strength range of the present invention for combining various properties as an outer panel such as flat hem workability and press workability, the cold rolling rate for obtaining these cube orientations, etc. , The critical significance of the requirements of the present invention is understood.

[0106]

[Table 1]

[0107]

[Table 2]

[0108]

[Table 3]

[0109]

[Table 4]

[0110]

EFFECTS OF THE INVENTION According to the present invention, the Al-Mg-Si system is excellent in bending workability such as flat hemming, and has other required properties such as press formability, artificial age hardening ability at low temperature, and corrosion resistance.
An Al alloy plate and a method for manufacturing the same can be provided. Therefore, it has a great industrial value in that the Al alloy plate can be expanded to panel applications.

[Brief description of drawings]

FIG. 1 is a perspective view showing a curved edge portion of an outer panel in flat hem processing.

FIG. 2 is an explanatory view schematically showing the shape of a flat hem processed portion of the outer panel.

[Explanation of symbols]

1: Outer panel, 2: Inner panel, A: Bent part

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22F 1/00 630 C22F 1/00 630A 630K 640 640A 685 685Z 686 686B 691 691B 691C 692 692A 692B 694A 694 Tetsuya Masuda 15 Kinugaoka, Moka City, Tochigi Prefecture Kamido Steel Works Co., Ltd. Moka Works (72) Inventor Manabu Nakai 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Works, Ltd.

Claims (11)

[Claims] 1. Si: 0.4 to 1.3%, Mg: 0.2 to 1.2%, Mn: 0.01
~ 0.65%, Cu: 0.001 ~ 1.0%, the balance is Al and Al-Mg-Si based aluminum alloy plate which is an unavoidable impurity, the ratio of the integrated strength of the {200} plane on the aluminum alloy plate surface is An aluminum alloy plate excellent in bending workability, which is 50% or more and the ratio of the total integrated strength of the {200} plane and the {400} plane is 60% or more. 2. The ratio of the integrated strength of the {200} plane on the surface of the aluminum alloy plate is 50 to 80%, and the ratio of the total integrated strength of the {200} plane and the {400} plane is
It is 60% -90%, The aluminum alloy plate excellent in bending workability of Claim 1. 3. The aluminum alloy plate excellent in bending workability according to claim 1, wherein the mass ratio Si / Mg of Si and Mg is 1 or more. 4. The electrical conductivity of the aluminum alloy plate is 43 to
The aluminum alloy plate excellent in bending workability according to any one of claims 1 to 3, which has a crystal grain size of 50 µm or less in addition to the range of 47IACS%. 5. The aluminum alloy plate having excellent bending workability according to claim 1, wherein the Si content is 0.6 to 1.2%. 6. The aluminum alloy plate excellent in bending workability according to claim 1, wherein the Cu content is regulated to 0.1% or less. 7. The 0.2% proof stress of the aluminum alloy plate is 14
The aluminum alloy plate having excellent bending workability according to any one of claims 1 to 6, which has a pressure of 0 MPa or more. 8. The inner panel aluminum alloy sheet having a thickness of 0.5 mm or more as an outer panel of the aluminum alloy sheet and having a sheet thickness of 1.3 mm or less is hem-processed. An aluminum alloy plate excellent in bending workability according to the item. 9. The aluminum alloy plate excellent in bending workability according to claim 1, wherein the bending work is flat hemming. 10. The aluminum alloy plate excellent in bending workability according to claim 1, wherein the aluminum alloy plate is for an automobile outer plate. 11. Si: 0.4 to 1.3%, Mg: 0.2 to 1.2%, Mn: 0.0
1-0.65%, Cu: 0.001-1.0% Al-Mg-Si based aluminum alloy sheet is cold-rolled at a reduction rate of 60% or more, and then annealed at a temperature of 350 ° C or less, if necessary, to form a solution and After heat treatment including quenching, the ratio of the integrated strength of the {200} plane on the aluminum alloy plate surface is 50% or more, and the ratio of the total integrated strength of the {200} and {400} planes is 60% or more ,
A method for producing an aluminum alloy sheet having excellent bending workability, which has an electric conductivity of 43 to 47 IACS% and a crystal grain size of 50 μm or less.