JP2000080431A - Al-Mg ALLOY SHEET EXCELLENT IN PRESS FORMABILITY - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy sheet excellent in bulging formability, deep drawability and a forming crack limit in the place from a tensile region to a plane strain region, as to a texture dominating plastic anisotropy, by controlling the ratio of respective crystal orientations and controlling the crystal grain sizes to specified ranges. SOLUTION: An alloy sheet excellent in bulging formability has a texture in which the volume fractional rate in the CUBE orientation is 5 to 20%, the volume fractional rate in the GOSS orientation is 1 to 5%, and each volume fractional rate in the BRASS orientation, S orientation and COPPER orientation is 1 to 10%, and whose crystal grain size is 20 to 70 μm. An alloy sheet excellent in deep drawability has a texture in which the ratio of the volume fractional rate in the CUBE orientation and the volume fractional rate in the S orientation (S/Cube) is >=1, and that in the GOSS orientation is <=10%, and whose crystal grain size is 20 to 100 μm. As to an alloy sheet high in a forming crack limit in the place from a tensile region to a plane strain region, the volume fractional rate in the CUBE orientation is 30 to 50%, the volume fractional rate in the BRASS orientation is 10 to 20%, and the crystal grain size is 50 to 100 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al-Mg based alloy sheet having excellent press formability, and particularly to a stretchable formability, a deep draw formability, a high forming crack limit in a tensile range to a plane strain range, and an automobile body. The present invention relates to an Al-Mg-based alloy plate suitable for a material such as a panel.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of consideration for the global environment and the like, social demands for reducing the weight of vehicles such as automobiles have been increasing more and more. In order to meet such demands, application of aluminum materials as materials for automobile body panels and the like instead of steel materials such as steel plates is being studied.

[0003] However, even if the aluminum material is similar in strength to a steel sheet, the press formability such as deep drawing and stretch forming is generally inferior, so that improvement in press formability is strongly desired. I have.

As an aluminum alloy plate having excellent press formability, aluminum alloy materials such as Al-Mg based JIS5052 alloy and JIS5182 alloy have been conventionally used, and others are disclosed in Japanese Patent Application Laid-Open No. 52-141409. Al-Mg based alloy materials. The Applicant has worked diligently on research and development and commercialization,
S5030 alloy and KS5032 alloy (both are trade names of Kobe Steel, whose contents are described in JP-A-60-125346, JP-A-63-89649, and JP-A-2-269.
937, JP-A-3-315486, and the like). These alloys provide high strength and high ductility by adding a high concentration of Mg,
It is characterized in that baking hardenability and stress corrosion cracking resistance are enhanced by adding a certain amount of Cu, and the crystal grain size is optimized by adding Mn and Cr.
These aluminum alloy plates are applied to automobile panels and the like.

[0005] However, these aluminum alloy sheets have insufficient formability, and there has been a demand from automobile manufacturers for further improvement in formability. The reason for insufficient formability was that the plastic anisotropy could not be controlled well. That is, JIS alloys such as JIS5182 alloy, KS50
Alloys developed by the present applicant such as No. 30 alloy and KS5032 alloy, or JP-A-52-141409, JP-A-60-125346, JP-A-63-89649, JP-A-2-269937, JP-A-3-31
The Al-Mg-based alloy disclosed in Japanese Patent No. 5486 and the like merely specifies alloy components, and no consideration is given to the texture that governs plastic anisotropy.

It has long been known that the texture governs the formability. For example, it is known that deep drawability can be improved by strongly developing (111) as a plane orientation in a cold rolled steel sheet. Recently, it has been proposed to improve the formability of aluminum alloys by controlling the texture of the sheet material. For example, Japanese Unexamined Patent Publication (Kokai) No. 5-295476 discloses that an aluminum alloy for deep drawing has a (110) orientation integration degree of 10% on a plate surface.
The above discloses an Al-Mg based alloy plate in which the (110) orientation and the (112) orientation have a degree of integration of 1.5 or more and a crystal grain size in the range of 35 to 80 µm. However, the texture shown here cannot be said to be optimal for deep drawing, and a texture excellent in deep drawing formability is required.

One of the present inventors has also invented an Al-Mg alloy excellent in stretch forming by controlling the texture (Japanese Unexamined Patent Publication No. Hei 8-
However, the texture defined therein is not always optimal for stretch formability, and it is necessary to clarify the relationship between stretch formability and texture. In addition, in the present invention, no consideration is given to the crystal grain size that largely affects the formability.

[0008] Turning to academic papers, Ratch
ev et al. calculated the relationship between the texture and formability of an Al-Mg alloy plate by computer based on the theory of plastic working.
It is reported that when the e-orientation develops strongly, the anisotropy increases and the formability decreases (Texture and
Microstructures, vol. 22, 19
1994, P219. ).

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to control the ratio of individual crystal orientations in a texture governing plastic anisotropy. Another object of the present invention is to provide an optimal Al-Mg-based alloy sheet having excellent press formability by optimizing the crystal grain size and limiting the types and amounts of the added elements to specific ranges. More specifically, of the press formability, Al-Mg based alloys having excellent properties for the purpose of improving the three properties of stretch formability, deep drawing formability, and forming crack limit in the tensile range to the plane strain range. The purpose is to provide a board.

[0010]

SUMMARY OF THE INVENTION Among the Al-Mg-based alloy sheets having excellent press formability of the present invention, the Al-Mg based alloy sheet having excellent stretch formability has a volume fraction of CUBE orientation as a texture. 5-20%, volume fraction of GOSS orientation is 1-5%, volume fraction of BRASS orientation, S orientation, COPER orientation is 1-10% each, and crystal grain size is 20-
The gist should be within the range of 70 μm. Preferably,
Volume fraction of CUBE orientation is 5 to 15%, volume fraction of GOSS orientation is 1 to 3%, BRASS orientation, S orientation, COP
The volume fraction of the PER orientation is 1 to 5%, respectively. further,
The crystal grain size is preferably 30 to 60 μm.

An Al—Mg based alloy sheet excellent in deep drawing formability has, as a texture, a ratio of the volume fraction of the CUBE orientation to the volume fraction of the S orientation (S / Cube) of 1 or more, and the GOSS orientation. Is 10% or less and the crystal grain size is 20% or less.
The gist is in the range of 〜100 μm. Preferably, the ratio (S / Cube) of the volume fraction of the CUBE orientation to the volume fraction of the S orientation is 2 or more, and the GOSS orientation is 5%.
It is as follows. Further, the crystal grain size is preferably 40 to 80 μm.

An Al—Mg based alloy sheet having a high forming crack limit from the tensile region to the plane strain region has a texture having a CUBE orientation volume fraction of 30 to 50% and a B
The gist is that the volume fraction of the RAS orientation is 10 to 20% and the crystal grain size is in the range of 50 to 100 μm.
Preferably, the volume fraction in the CUBE azimuth is 40 to 50% and the volume fraction in the BRASS azimuth is 15 to 20%.
Further, the particle size is more preferably 60 to 90 μm.

Further, each of these Al-Mg alloy plates contains 2 to 6 wt% of Mg, and contains Fe, Mn, Cr,
One or more selected from Zr and Cu are included in a total of 0.1.
It is preferable that the composition contains not less than 03 wt% (when Cu is selected, not less than 0.2 wt% as Cu) and the balance being Al.

By appropriately controlling the texture, crystal grain size, and additional elements of the Al-Mg alloy sheet as described above, press formability can be improved. Specifically, it is possible to obtain an aluminum alloy sheet that is excellent in stretch formability or deep draw formability, or has a high forming crack limit from a tensile region to a plane strain region, and is suitable for an automobile body panel or the like.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The texture of an ordinary aluminum alloy sheet mainly includes a CUBE orientation, a GOSS orientation, and a BRA orientation.
It is composed of the SS direction, the S direction, and the COPER direction, and when these volume fractions change, the plastic anisotropy changes. Here, the formation of the texture differs depending on the processing method even in the case of the same crystal system, and in the case of a rolled sheet material, it is necessary to express the texture by the rolling surface and the rolling direction. The rolling surface is represented by (（), and the rolling direction is represented by <△△△> (○ and を indicate integers). Based on such an expression method, the CUBE direction,
GOSS direction, BRASS direction, S direction, COPER
The azimuth is represented as follows.

CUBE direction (100) <001> GOSS direction (110) <001> BRASS direction (110) <1-12> S direction (123) <63-4> COPER direction (112) <11-1> In the specification, a deviation of azimuth within ± 10 degrees from these azimuths is defined as belonging to the same azimuth factor. In addition, when indicating the bearing, it is common to display a numerical value in the negative direction with a bar above the numerical value. However, in this specification, for convenience, a "-" sign is added before the numerical value. To display this.
Also, an orientation other than these orientation factors is defined as a random orientation.

The inventors of the present invention have found that a change in plastic anisotropy corresponding to a change in texture causes a stretch formability, a deep draw formability,
The optimum morphology for the three characteristics of forming crack limit in the tensile range to the plane strain range was clarified. Hereinafter, each molding characteristic will be described.

(1) Relationship between Overhang Formability and Texture An excellent overhang formability means that the crack limit under biaxial stress is high. There are three governing factors for this: low plastic anisotropy, high work hardening ability, and high value of strain rate sensitivity index. It has been known from the past that a material having a weak texture is excellent in stretch formability, but when a sheet is manufactured by rolling, it is impossible to obtain a completely isotropic material (in other words, a weak texture). Impossible, some direction becomes stronger.

As a result of examining the relationship between the volume fraction of each direction and the overhang property based on many experimental results, it was found that CUB
The volume fraction in the E direction is 5% or more and 20% or less, preferably 15% or less, and the volume fraction in the GOSS direction is 1% or more and 5%.
Or less, preferably 3% or less, BRASS orientation, S orientation,
It has been found that when the volume fraction of the COPER orientation is 1% or more and 10% or less, and preferably 5% or less, a structure having weak plastic anisotropy, that is, a structure having the most excellent overhang property is obtained.

Regarding the method of quantitative evaluation of texture,
The orientation of each grain is determined for each of the 100 crystal grains by the electron channeling pattern method, one of the above five orientations is determined, and it is assumed that all grains have the same size. Thus, the volume fraction in each direction was calculated. Hereinafter, the method of quantitatively evaluating the texture in the present specification is the same.

(2) Relationship between Deep Drawing Formability and Texture The phrase "excellent deep drawing formability" means that the plate is easily drawn down at the flange portion and hardly broken at the punch side or the punch bottom. For this purpose, plastic deformation is easy when tension is applied in one direction (compression stress is applied in the direction perpendicular to the tension direction), and when tension is applied in two directions (tensile stress is applied in two directions). It is necessary that the strength is high.

The present inventors have conducted intensive studies on the relationship between the texture and LDR (critical drawing ratio), which is an index of deep drawability, and found that the Cube orientation and the Goss orientation lower the LDR, and the S orientation the LDR. To improve,
It was revealed that the effects of other orientations were negligible.
Of the findings described above, only the view was previously known (a dissertation by one of the present inventors), but the present inventors conducted experiments on the relationship between the volume fraction of other orientations and the deep drawability. It was newly found based on the results.

Based on the above findings, the texture of the Al—Mg alloy was determined to have a ratio of the volume fraction of the CUBE orientation to the volume fraction of the S orientation (S / Cube) of 1 or more, preferably 2 or more, and GOSS When the orientation is 10% or less, preferably 5% or less, the LDR becomes high, and the deep drawability is excellent.
In addition, the aluminum alloy for deep drawability described in JP-A-5-295476 has a degree of integration of (110) orientation corresponding to GOSS or BRASS orientation of 10% or more, and has a (110) orientation and a COPER orientation. Applicable (11
2) Attention is paid to the point that the integration degree ratio of the azimuth is 1.5 or more and the S azimuth ratio is not specified, and the ratio (S / Cube) of the volume fraction of the CUBE orientation to the volume fraction of the S azimuth. There is no difference from the present invention.

(3) Relationship between Forming Crack Limit and Texture in Tensile Region to Plane Strain Region As a result of extensive studies by the present inventors, the forming crack limit in the tensile region to plane strain region is not affected by plastic anisotropy. It was clarified that work hardening characteristics and strain rate sensitivity were dominant, especially work hardening characteristics were affected by texture, and that the more anisotropic the texture, the better the work hardening characteristics.

The texture having a high forming crack limit from the tensile region to the plane strain region has a volume fraction of CUBE orientation of 30% or more, preferably 40% and 50% or less, and a volume fraction of BRASS orientation of 10% or less. % Or more, preferably 15% or more and 20% or less.

(4) Relationship between press formability and crystal grain size (a) Overhanging formability The smaller the crystal grain size, the more uniform the deformation, the higher the strain rate sensitivity index, and the better the overhanging formability.

The present inventors have conducted intensive studies and found that the crystal grain size is 20 μm or more, preferably 30 μm or more,
It has been found that it is optimal to be in the range of less than μm, preferably less than 60 μm. If it is less than 20 μm, a stretch strain mark is generated during molding, which is not preferable. If it exceeds 70 μm, grain boundary destruction is likely to occur, which is not preferable.

In the measurement of the crystal grain size, the average section length was determined by a cross-cut method based on an optical microscope photograph at a magnification of 100 times, and this was defined as the average crystal grain size. Hereinafter, the same applies in the present specification.

(B) Deep drawing formability When the crystal grain size is 20 μm or more, preferably 40 μm or more,
When the thickness is in the range of 100 μm or less, preferably 60 μm or less, the deep drawability is good. If the thickness is less than 20 μm, a stretch strain mark is generated at the bottom of the squeezed product to impair the appearance of the product, and if it exceeds 100 μm, an orange peel (rough skin) occurs on the surface of the product and the appearance of the product is impaired. It is.

(C) Forming crack limit from tensile region to plane strain region Forming crack limit from tensile region to plane strain region is not affected by plastic anisotropy, and work hardening characteristics and strain rate sensitivity are dominant. In particular, it has been found that work hardening characteristics are affected by texture. And it turned out that work hardening characteristic improves, so that a crystal grain size is large.
However, if the crystal grain size is too large, orange peels (skin roughness) occur during molding, which significantly impairs the appearance of the product.

Therefore, the crystal grain size is 50 μm or more, preferably 60 μm or more, and 100 μm or less, preferably 90 μm or less.
When the thickness is in the range of μm or less, the forming crack limit in the tensile region to the plane strain region increases.

(5) Chemical Composition The chemical composition of the aluminum alloy of the present invention is, as described below, 2% by weight ≦ 2% by weight ≦ Mg ≦ 6% by weight of Mg.
And at least one selected from Fe, Mn, Cr, Zr, and Cu in a total amount of 0.03 wt% or more (when Cu is selected, 0.2 wt% or more as Cu). The upper limit of the element content is Fe ≦ 0.2 wt%, Mn
≦ 0.6wt%, Cr ≦ 0.3wt%, Zr ≦ 0.3w
It is preferable that t% and Cu ≦ 1.0%. Since these additional elements greatly affect the texture formation and change the plastic anisotropy, the texture can be optimized by optimizing the amount of the additional elements and the process conditions corresponding thereto.

2 wt% ≦ Mg ≦ 6 wt% Mg is an important element that enhances work hardening ability, uniformly plastically deforms the material, and improves the limit of fracture cracking. If the Mg content is less than 2 wt%, the hardening of the Mg content is insufficient, and if it exceeds 6 wt%, the production becomes difficult, and the grain boundary fracture is liable to occur during molding. Desirably.

At least one selected from the group consisting of Fe, Mn, Cr, Zr, and Cu in a total amount of at least 0.03 wt% (C
When u is selected, 0.2 wt% or more as Cu),
And the upper limit of the content of each element is Fe ≦ 0.2 wt%,
Mn ≦ 0.6 wt%, Cr ≦ 0.3 wt%, Zr ≦ 0.
3 wt%, Cu ≦ 1.0 wt% The addition of Fe, Mn, Cr, and Zr is effective in refining crystal grains and plays an important role in controlling texture. Grain boundary fracture is likely to occur when the crystal grain size is large, and the smaller the crystal grain size, the better. Therefore, it is preferable to add Fe, Mn, Cr, and Zr, which are elements effective for crystal grain refinement. Also, these elements improve the strain rate sensitivity index and improve the forming limit. When the strain rate sensitivity index shows a positive value, it means that the strain until the start of constriction during molding increases. However, Fe, Mn, Cr, Z
If the total content of r is less than 0.03 wt%, there is no effect of addition, while the upper limit of each element (that is, the content of Fe is 0.2 wt%, the content of Mn is 0.6 wt%, and the content of Cr is If the ratio exceeds 0.3 wt% and the Zr content exceeds 0.3 wt%), a coarse compound is formed and becomes a starting point of destruction, so that moldability deteriorates.

Cu is an element which improves work hardening ability, improves paint bake hardening characteristics, and further improves stress corrosion cracking resistance, and has the effect of changing the texture.
However, if it is less than 0.2 wt%, there is no effect of addition, and 1.0 w
If the content exceeds t%, a coarse compound is formed, which becomes a starting point of destruction, and thus the moldability deteriorates.

(6) Texture and Manufacturing Conditions The aluminum alloy sheet of the present invention is manufactured through ordinary steps of casting, homogenizing heat treatment, hot rolling, cold rolling, and final annealing. The obtained texture changes depending on the setting conditions of each step.

First, when a transition metal such as Mn, Cr, Fe, or Zr is contained, it is important to control the precipitate to a desired form. This is because these precipitates act as preferential nucleation sites for the recrystallization orientation and govern the texture formed. In addition, these precipitates also control the crystal grain size and greatly influence the limit of forming cracks. Therefore, the optimum conditions in the homogenization heat treatment process are also
If the type and the amount of the transition metal such as Mn, Cr, Fe, and Zr change, the ratio changes, and therefore cannot be determined uniquely.

Optimum conditions of the hot rolling step and the cold rolling step performed after the homogenizing heat treatment step vary depending on the form of the precipitate formed by the homogenizing heat treatment. There are combinations of high-temperature rolling, low-temperature rolling, high-pressure cold rolling, low-pressure cold rolling, and the like, but these combinations cannot be uniquely determined. further,
After the annealing after the hot rolling, cold rolling may be performed, or intermediate annealing may be performed during the cold rolling. The optimum rolling conditions differ depending on whether or not intermediate annealing is performed during the intermediate rolling.

After the cold rolling, a final heat treatment (solution treatment) is performed. The texture changes also depending on the solution treatment conditions.

That is, in order to obtain the preferred texture shown in the claims, it is necessary to adjust the rolling conditions, the roughening conditions, the solution treatment conditions, etc. each time when the alloy components and the homogenizing heat treatment conditions change. is there. That is, even if they have the same alloy composition. This is because an optimal texture can be formed by controlling the homogenizing heat treatment conditions, rolling conditions, roughening conditions, solution treatment conditions, and the like in a complex manner, and press formability can be greatly improved. . Therefore, although these manufacturing conditions individually overlap with the conventional manufacturing conditions, a texture suitable for formability required by performing a special combination as a series of manufacturing steps is adopted. Can be obtained.

However, there is a tendency that when the final cold rolling reduction is low, it is easy to obtain a texture excellent in deep drawing formability, and when the final cold rolling reduction is around 50%, an assembly excellent in stretch forming property is obtained. It can be said that when the structure is easy to obtain and the final cold rolling reduction is high, the forming crack limit from the tensile region to the plane strain region tends to be high. Here, the final cold rolling reduction refers to the rolling reduction performed after annealing when annealing is performed during cold rolling, and the cold rolling reduction is the final cold rolling reduction when annealing is not performed during cooling. Becomes

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific embodiments.

In the following examples, the crystal grain size of the obtained structure was measured by a line cutting method on a plane perpendicular to the rolling surface and perpendicular to the rolling direction. In the measurement of the crystal grain size, an average section length was determined by a cross-cut method for a photomicrograph at a magnification of 100 times, and this was defined as the average crystal grain size.

Regarding the texture, the orientation of each crystal grain is determined for 100 crystal grains by the electron channeling pattern method, which of the above five orientations is determined, and the volume fraction of each orientation is calculated. (The size of each grain was assumed to be the same.)

Embodiment 1: Preferred embodiment of the invention according to claim 1 An Al-5% Mg-0.1% Fe alloy is ingot-formed by ordinary DC casting (semi-continuous casting) to have a width of 400 mm and a thickness of 150 mm.
mm and a length of 3000 mm were obtained. 480 ° C
, And then a two-stage homogenizing heat treatment of holding at 440 ° C. for 4 hours, followed by hot rolling to obtain a plate having a thickness of 5 mm. The starting temperature of the hot rolling was 440 ° C., which is the temperature of the homogenization heat treatment performed immediately before, and the ending temperature of the hot rolling was 320 ° C. After hot rolling, cold rolling
Although a sheet material having a thickness of 1 mm is used, an intermediate annealing is appropriately performed during the cold rolling, so that the final cold rolling reduction is 17% to 80%.
Adjusted within the range. If the intermediate annealing is not performed, cold rolling is performed at once from 5 mm to 1 mm, and the final cold rolling reduction is 80%.

The sheet material having a thickness of 1 mm obtained by cold rolling was subjected to a solution treatment at a temperature and a holding time shown in Table 1 to obtain a sheet No. having a crystal grain size and texture as shown in Table 1. 1 to 15 plate materials were obtained. Here, heating to the solution treatment temperature was performed by two types of rapid heating (60000 ° C./h) and slow heating (300 ° C./h).

The obtained No. About 1-15 board materials,
The following bulge overhang test was performed. That is, the periphery of a 100 mm diameter plate test piece was fixed to a 50 mm diameter mold, and the test piece was lowered by applying hydrostatic pressure to one surface of the test piece. I asked. The amount of strain was measured by pressing a 3 mm square checkerboard stamp on the surface of the plate test piece and measuring the dimensional change. The results are shown in Table 1 together with the production method (final cold rolling rate, solution treatment temperature and holding time, heating rate), crystal grain size and texture.

[0048]

[Table 1]

From Table 1, it can be seen that in each of the examples, the distortion amount was 0.4.
Although it exceeded 0 mm, the ss mark occurred in the comparative example even if it was less than 0.38 mm or more than 0.38 mm (No.
14) It can be seen that the sheet material of the present invention exhibits more excellent stretch formability than the comparative example.

Embodiment 2: Preferred embodiment of the invention according to claim 2 An Al-5% Mg-0.1% Fe alloy is ingot-formed by ordinary DC casting (semi-continuous casting) to have a width of 400 mm and a thickness of 150 mm.
mm and a length of 3000 mm were obtained. 520 ° C
, And a two-stage soaking heat treatment at 460 ° C. for 4 hours, and a hot-rolled sheet having a thickness of 5 mm. The starting temperature of hot rolling is 460 ° C and the ending temperature is 330
° C. After the hot rolling, a sheet material having a thickness of 1 mm was formed by cold rolling, and the final cold rolling reduction was adjusted in the range of 17% to 80% by appropriately performing intermediate annealing during the cold rolling. If intermediate annealing is not performed, 5 mm by cold rolling
From 1 to 1 mm, and the final cold rolling reduction is 80%.

The sheet material having a thickness of 1 mm obtained by cold rolling was subjected to a solution treatment for holding at a temperature and a holding time shown in Table 2 to obtain a sheet No. having a crystal grain size and texture as shown in Table 2. 21 to 28 plate materials were obtained. Here, heating to the solution treatment temperature was performed by two types of rapid heating (60000 ° C./h) and slow heating (300 ° C./h).

The obtained plate material test piece No. For 21 to 28, the limit drawing ratio (LDR) was measured. The limit drawing ratio (LDR) is measured by preparing disk specimens of various diameters, deep-drawing with a punch of the following dimensions, and limiting the ratio between the diameter of the specimen and the diameter of the punch when deep-drawing is not possible. The aperture ratio was used. The larger the limit drawing ratio, the better the deep drawing formability. The oil used in the measurement test was
Solid lubricant KS-3 (Kobe Steel Development). Measurement conditions of LDR test Die material SKD11 Punch diameter 50mm (flat head) Die holder diameter 52.8mm Die shoulder R6.0mm BHF 0.5t Punch speed 850mm / min

Table 2 shows the critical draw ratio (LDR) of the final cold rolling reduction, heating rate, solution treatment temperature and holding time, crystal grain size, and texture (volume fraction of CUBE orientation and S
Along with the volume fraction of the azimuth (S / Cube) and the volume fraction of the GOSS azimuth.

[0054]

[Table 2]

From Table 2, it can be seen that the plate material of the present invention has a lower L than the comparative example.
It turns out that DR is high and it is excellent in deep drawing formability.

Embodiment 3 Preferred Embodiment of the Invention According to Claim 3 An Al-5% Mg-0.1% Fe alloy is ingot-formed by ordinary DC casting (semi-continuous casting) to have a width of 400 mm and a thickness of 150 mm.
mm and a length of 3000 mm were obtained. 480 ° C
At 48 hours, and 5mm by hot rolling
It was a thick plate. The starting temperature of the hot rolling was 480 ° C and the ending temperature was 340 ° C. After the hot rolling, a cold-rolled sheet material having a thickness of 1 mm is obtained. Intermediate annealing is appropriately performed during the cold rolling to reduce the final cold-rolling rate to 17% to 8%.
The adjustment was made in the range of 0%. If the intermediate annealing is not performed, cold rolling is performed at once from 5 mm to 1 mm, and the final cold rolling reduction is 80%.

The sheet material having a thickness of 1 mm obtained by cold rolling was subjected to a solution treatment at a temperature and a holding time shown in Table 3 to obtain a sheet having a grain size and texture as shown in Table 3. 31 to 37 plate materials were obtained. Here, heating to the solution treatment temperature was performed by two types of rapid heating (60000 ° C./h) and slow heating (300 ° C./h).

No. A test piece having the shape shown in FIGS. 1 and 2 was cut out from the plate material of Nos. 31 to 37, a biaxial tensile test was performed using the test piece shown in FIG. 1, and a uniaxial tensile test was performed using the test piece shown in FIG. The test was performed. In each case, the amount of strain when the test piece was broken was measured, and the strain ratio with respect to the start of the test was determined. Incidentally, in the test using the test piece shown in FIG. 1, the strain amount at the time of breaking limit in the plane strain region,
In the test using the test piece shown in FIG. 2, the strain amount at the breaking limit in the uniaxial tensile region can be found. In each case, the larger the numerical value, the higher the breaking limit.

The measurement results were measured according to the production method (final cold rolling reduction,
The results are shown in Table 3 together with the solution treatment temperature and holding time, heating rate), crystal grain size and texture.

[0060]

[Table 3]

As is clear from Table 3, the sheet material of the present invention is higher in both plane strain and uniaxial tension than in the comparative example, and the forming crack limit in the range from the tensile region to the plane strain region is high.

Embodiment 4: Preferred embodiments of the invention according to claim 4 An alloy having the composition shown in Tables 4 and 5 was ingot-formed by ordinary DC casting (semi-continuous casting) to have a width of 400 mm and a thickness of 150 mm. 3,000 mm long ingot was obtained. Apply the homogenizing heat treatment shown in Tables 4 and 5 and hot roll 5m
m-thick plate. The starting temperature of the hot rolling was the homogenizing heat treatment temperature (the temperature of the second stage in the case of the two-stage soaking), and the ending temperature of the hot rolling was a temperature about 150 ° C. lower than the starting temperature. Thereafter, a plate having a thickness of 5 mm to 1 mm was formed by cold rolling. At this time, the final cold rolling reduction was adjusted to 50% and 17% by performing intermediate annealing on the way. Then 53
The solution was subjected to a solution treatment at 0 ° C., and had a crystal grain size and texture as shown in Tables 4 and 5. Plate materials 41 to 73 were obtained. Here, heating to the solution treatment temperature was performed by rapid heating (60000 ° C./h) in all cases.

The obtained No. A bulge overhang test was performed on the plates 41 to 73 in the same manner as in Example 1.
The measurement results are shown in Tables 4 and 5 together with the production method (final cold rolling reduction, solution treatment temperature and holding time, heating rate), crystal grain size and texture. Table 4 is an example and Table 5
Is a comparative example.

In the homogenization heat treatment conditions in the table, A:
The display of B indicates that the sample was held at A ° C. for B hours, and that the process was performed in two stages from the upper stage to the lower stage of “↓”. Hereinafter, the same applies in the present specification.

[0065]

[Table 4]

[0066]

[Table 5]

Table 5 (corresponding to the comparative example) has a value of the basil test cracking strain of 0.37 or less in each case, whereas the value of the basil test cracking strain shown in Table 4 (corresponding to the example) is less than 0.37. All were excellent at 0.38 or more.

Embodiment 5: Preferred embodiment of the invention according to claim 5 The alloys shown in Tables 6 and 7 were ingot-formed by ordinary DC casting (semi-continuous casting) and 400 mm in width, 150 mm in thickness and 150 mm in length A 3000 mm ingot was obtained. The sheets were subjected to the homogenizing heat treatment shown in Tables 6 and 7, and were hot-rolled into 5 mm-thick plates. The starting temperature of the hot rolling was the homogenizing heat treatment temperature (the temperature of the second stage in the case of the two-stage soaking), and the ending temperature of the hot rolling was about 150 ° C. lower than that. Thereafter, a plate having a thickness of 5 mm to 1 mm was formed by cold rolling. At this time, by performing or not performing intermediate annealing in the middle,
The final cold rolling reduction was 17%, 50%, and 80%. When the intermediate annealing is not performed, the final cold rolling reduction is 80%.

Thereafter, a solution treatment was performed by maintaining the temperature at 400 ° C. or 530 ° C., and the sample No. 1 having a crystal grain size and texture as shown in Tables 4 and 5 was obtained. Plate materials 81 to 113 were obtained. Here, heating to the solution treatment temperature was performed by two types of rapid heating (60000 ° C./h) or slow heating (300 ° C./h).

The obtained No. The limit drawing ratio (LDR) measurement test was performed on the plates 81 to 113 in the same manner as in Example 2. The measurement results are shown in Tables 6 and 7 together with the composition, the production method (final cold rolling ratio, homogenization heat treatment conditions, solution treatment conditions), crystal grain size, and texture. Table 6 corresponds to Examples and Table 7 corresponds to Comparative Examples.

[0071]

[Table 6]

[0072]

[Table 7]

In the case of the embodiment of the present invention (Table 6),
The LDR was as high as 2.08 or more, whereas the LDR was as low as 2.01 or less in Comparative Example (Table 7) or 2.0% or less.
Even if two or more LDRs were obtained, orange peel was generated and stretcher strain marks (ss marks) were generated, resulting in a poor product.

Embodiment 6: Preferred embodiment of the invention according to claim 6 The alloys shown in Tables 8 and 9 were ingot-formed by ordinary DC casting (semi-continuous casting) to have a width of 400 mm and a thickness of 150 m.
m, an ingot having a length of 3000 mm was obtained. A homogenizing heat treatment shown in Tables 8 and 9 was performed, and a 5 mm-thick plate was formed by hot rolling. The starting temperature of the hot rolling was the homogenizing heat treatment temperature (the temperature of the second stage of the two-stage soaking), and the ending temperature of the hot rolling was about 150 ° C. lower than that. Thereafter, a plate having a thickness of 5 mm to 1 mm was formed by cold rolling. At this time, by performing intermediate annealing or not performing intermediate annealing in the middle, the final cold rolling reduction is 17%, 50%, 80%.
(When no intermediate annealing is performed). Then 53
No. 3 having a crystal grain size and texture as shown in Tables 8 and 9 after solution treatment at 0 ° C. Sheet materials 121 to 153 were obtained. Here, the heating to the solution treatment temperature is performed by rapid heating (60000 ° C./h) or slow heating (300 ° C./h).
Made by kind.

The obtained No. A tensile test using a specially shaped test piece was performed on the plates 121 to 153 in the same manner as in Example 3. The results are shown in Tables 8 and 9 together with the composition, production method (final rolling reduction, homogenizing heat treatment conditions, heating rate), particle size and structure. Table 8 shows a case corresponding to the example of the present invention, and Table 9 shows a case corresponding to the comparative example of the present invention.

[0076]

[Table 8]

[0077]

[Table 9]

In Examples (Table 8), the breaking limit under uniaxial tension was 0.35 or more, and the breaking limit of plane strain was 0.30 or more. On the other hand, in Comparative Example (Table 9), the breaking limit under uniaxial tension is less than 0.35, the breaking limit of plane strain is less than 0.30, and in some cases, orange peel is observed. Was.

[0079]

The Al-Mg based alloy sheet of the present invention is excellent in press formability, specifically, stretch formability or deep draw formability, or has a high forming crack limit from a tensile region to a plane strain region. In addition, the texture, the crystal grain size, and the added elements are appropriately controlled. Therefore, the Al of the present invention
-Mg-based alloy plates are suitable as aluminum alloy plates used for automobile body panels and the like.

[Brief description of the drawings]

FIG. 1 is a plan view showing the shape of a test piece (wide tensile test piece) used for a tensile test in a plane strain region.

FIG. 2 is a plan view showing a shape of a test piece used for a tensile test in a uniaxial tensile region.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Koji Maeda 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor, Yasuhiro Hayashida 1 Takatsukadai, Nishi-ku, Kobe-shi Kobe Steel Research Institute Kobe Research Institute Kobe Steel Co., Ltd. (72) Inventor Shigeo Hattori 1-5-5 Takatsukadai, Nishi-ku, Kobe City Kobe Steel Research Institute Kobe Research Institute (72) Inventor Kuniaki Matsui 15 Kinuigaoka, Moka City, Tochigi Prefecture Kobe Steel, Ltd.Moka Works (72) Inventor Seiichi Hashimoto 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Kobe Steel Tokyo Main Office (72) Inventor Frederick Barrat Technical Drive, Alcoa Center, Pennsylvania, 15069-0001 USA 1 00, Aluminum Company of America, Alcoa Technical Center (72) Inventor John Seablem United States, 15069-0001 Pennsylvania, Alcoa Center, Technical Drive 100, Aluminum Company of America, Alcoa Technical Center (72) Invention Daniel Jay Lage United States, 15069-0001 Pennsylvania, Alcoa Center, Technical Drive 100, Aluminum Company of America, Alcoa Technical Center (72) Inventor Shaun Jay Martha United States of America, 15069-0001 Pennsylvania, Alcoa Center, Technical Drive 100, Aluminum Company of America, Alcoa Technical Center (72) Inventor Kwan Seo Chan South Korea , Shin rim - Don 56-1, Seoul National University, in the Faculty of Engineering

Claims (6)

[Claims] 1. An Al-Mg based alloy plate, comprising CUBE
Orientation volume fraction of 5% or more and 20% or less, GOSS orientation volume fraction of 1% or more and 5% or less, BRASS orientation, S orientation, and COPER orientation volume fraction of 1% or more and 10%, respectively
Has the following texture and a crystal grain size of 20 to 70 μm
A excellent in press formability characterized by being in the range of A
l-Mg based alloy plate. 2. An Al—Mg alloy plate, comprising CUBE.
The ratio of the volume fraction in the azimuth to the volume fraction in the S azimuth (S / Cub
e) An Al-Mg based alloy sheet excellent in press formability, characterized by having a texture of 1 or more, a GOSS orientation of 10% or less, and a crystal grain size in a range of 20 to 100 µm. 3. An Al—Mg alloy plate, comprising CUBE.
It has a texture in which the volume fraction in the azimuth is 30% or more and 50% or less, the volume fraction in the BRASS orientation is 10% or more and 20% or less, and the crystal grain size is in the range of 50 to 100 μm. Al-Mg based alloy sheet with excellent press formability. 4. The Al—Mg based alloy sheet according to claim 1, which contains 2 wt% ≦ Mg ≦ 6 wt% of Mg,
e, Mn, Cr, Zr, and at least one selected from Cu and Cu in an amount of 0.03 wt% or more (when Cu is selected, 0.2 wt% or more as Cu). The upper limit of the content is Fe ≦ 0.2 wt%, Mn ≦ 0.
6 wt%, Cr ≦ 0.3 wt%, Zr ≦ 0.3 wt%,
Al-Mg excellent in press formability with Cu ≦ 1.0%
Alloy plate. 5. The Al—Mg-based alloy sheet according to claim 2, wherein 2% by weight ≦ Mg ≦ 6% by weight of Mg,
e, Mn, Cr, Zr, and at least one selected from Cu and Cu in an amount of 0.03 wt% or more (when Cu is selected, 0.2 wt% or more as Cu). The upper limit of the content is Fe ≦ 0.2 wt%, Mn ≦ 0.
6 wt%, Cr ≦ 0.3 wt%, Zr ≦ 0.3 wt%,
Al-Mg excellent in press formability with Cu ≦ 1.0%
Alloy plate. 6. The Al—Mg based alloy sheet according to claim 3, which contains 2 wt% ≦ Mg ≦ 6 wt% of Mg,
e, Mn, Cr, Zr, and at least one selected from Cu and Cu in an amount of 0.03 wt% or more (when Cu is selected, 0.2 wt% or more as Cu). The upper limit of the content is Fe ≦ 0.2 wt%, Mn ≦ 0.
6 wt%, Cr ≦ 0.3 wt%, Zr ≦ 0.3 wt%,
Al-Mg excellent in press formability with Cu ≦ 1.0%
Alloy plate.