JP4063388B2 - Al-Mg-Si-based aluminum alloy plate for forming with excellent surface properties and method for producing the same - Google Patents

Description

【００２０】
（実施例２）
表２に示すＭｇ、Ｓｉ、Ｍｎ、Ｃｒ、Ｆｅ、Ｚｒ、Ｖ、Ｔｉなどの合金成分を含有する種々の合金を通常の方法で鋳造し、５５０℃で８ｈｒの均質化処理を施した。その後熱間圧延（開始温度：５００℃）を行い、終了温度を変えて、１０〜１．５ｍｍ厚さの板とした。そして荒鈍を行うことなく冷間圧延で１ｍｍ厚さの板とした後、５５０℃で１分の溶体化処理を施した。
【００２１】
【表２】

【００２２】
これらの板材について、リジングマーク発生の有無の判定、張り出し成形試験による割れ限界高さの測定及び集合組織の測定を実施例１と同様に行った。
表３にその結果を示す。本発明材においてリジングマークの発生が抑制され、かつ成形性に優れていることが明らかである。
【００２３】
【表３】

【００２４】
（実施例３）
表４に示すＭｇ、Ｓｉ、Ｍｎ、Ｃｒ、Ｆｅ、Ｚｒ、Ｖ、Ｔｉ、Ｃｕ、Ａｇ、Ｚｎ、Ｓｎなどの合金成分を含有する種々の合金を通常の方法で鋳造し、５５０℃で８ｈｒの均質化処理を施した。その後熱間圧延（開始温度：５００℃）を行い、終了温度を変えて、１０〜１．５ｍｍ厚さの板とした。そして荒鈍を行うことなく冷間圧延で１ｍｍ厚さの板とした後、５５０℃で１分の溶体化処理を施した。
【００２５】
【表４】

【００２６】
これらの板材について、リジングマーク発生の有無の判定、張り出し成形試験による割れ限界高さの測定及び集合組織の測定を実施例１と同様に行った。
表５にその結果を示す。本発明材においてリジングマークの発生が抑制され、かつ成形性に優れていることが明らかである。
【００２７】
【表５】

【００２８】
【発明の効果】
本発明によれば、リジングマークが抑制された成形加工用Ａｌ−Ｍｇ−Ｓｉ系アルミニウム合金板を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an Al—Mg—Si-based aluminum alloy plate (hereinafter, “aluminum” is omitted) excellent in press formability and particularly excellent in surface properties, for example, building materials such as roofs, interiors, curtain walls, equipment, The present invention relates to an Al—Mg—Si alloy plate suitable for materials such as electric parts, optical equipment, automobiles, railway vehicles, airplanes and other transportation equipment, and general machine parts.
[0002]
[Prior art]
As an aluminum plate and aluminum alloy excellent in formability, Al-Mg based alloys have been mainly used conventionally, but since paint bake hardenability is inferior and stretcher strain marks are likely to occur during press molding, As an alternative alloy, an Al—Mg—Si based alloy has been attracting attention. Al-Mg-Si alloys have the advantage that they are excellent in formability and corrosion resistance at room temperature, and high strength can be obtained by aging treatment.
[0003]
However, when an Al—Mg—Si based alloy sheet is formed, surface roughness called ridging marks is generated on the surface of the sheet, as described in JP-A-7-228956 and JP-A-8-232052. It is a problem to do. A ridging mark is a streaky unevenness newly generated in a direction parallel to the rolling direction when a plate material is formed, and in particular, processing at 90 ° with respect to the rolling direction, for example, tensile processing, ironing processing, depth processing, etc. This occurs remarkably when drawing and overhanging are performed. When this ridging mark is generated, it cannot be used as an appearance defect in a product that requires particularly beautiful surfaces such as interiors, camera cases, and automobile outer plate materials.
[0004]
JP-A-7-228956 and JP-A-8-232052 describe hot rolling conditions and other processing conditions as a method for preventing the generation of ridging marks on Al-Mg-Si alloy sheet materials. It is intended to prevent generation of ridging marks by strictly controlling and generating crystal grains having fine and crystallographic orientations random.
However, these prior arts do not elucidate the structure of the plate material itself in which ridging marks are not generated, and this is not sufficient for the recent severe demand for the surface quality.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of such problems, and an Al-Mg-Si-based aluminum alloy plate for forming processing in which ridging marks generated in conventional Al-Mg-Si-based alloy plate materials are suppressed is provided. The purpose is to provide.
[0006]
[Means for Solving the Problems]
In order to suppress the generation of ridging marks in the Al—Mg—Si based alloy sheet material, the present inventors perform precise texture control beyond the conventional technique, and the Goss orientation, It has been found that it is effective to suppress the occurrence of PP orientation and Brass orientation.
That is, the Al—Mg—Si based alloy plate for forming process with excellent surface properties according to the present invention is an Al—Mg—Si based alloy plate, and the texture distribution has an orientation distribution density of 3 or less as a texture. It is characterized in that the PP distribution has a density distribution of 3 or less and the Brass distribution has an orientation distribution density of 3 or less.
[0007]
The Al—Mg—Si based alloy used in the present invention contains Mg: 0.2 to 1.5%, Si: 0.2 to 1.5% , and (1) Mn: 1.0 wt%. Hereinafter, Cr: 0.3 wt% or less, Fe: 1.0 wt% or less, Zr: 0.3 wt% or less, V: 0.3 wt% or less, Ti: 0.1 wt% or less, or one or more of them 0.01-1.5 wt% in total, (2) Cu: 1.0 wt% or less, Ag: 0.2 wt% or less, Zn: 1.0 wt% or less, Sn: 0.2 wt% or less It contains two or more kinds in total in a range of 0.01 to 1.5 wt%, or a combination of both, and consists of the balance Al and inevitable impurities.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As a result of various studies conducted by the present inventors to elucidate the cause of the generation of ridging marks during press forming of conventional aluminum alloys, it is clear that ridging marks are generated because the texture is not sufficiently controlled. Became.
Here, the texture of the aluminum alloy will be described. In the case of an aluminum alloy, the following textures called Cube orientation, RW orientation, CR orientation, Brass orientation, Goss orientation, PP orientation, C orientation, and S orientation exist.
Cube orientation... {001} <100>
RW orientation ... {001} <110>
CR orientation ... {001} <520>
Brass direction ・ ・ {011} < 211 >
Goss direction ... {011} <100>
PP orientation ... {011} <122>
C-direction ... {112} <111>
S-direction ... {123} <634>
In the present invention, basically, a deviation in orientation within ± 10 degrees from these orientations is defined as belonging to the same orientation factor. However, with respect to the Brass orientation and PP orientation, the deviation of orientation within ± 8 degrees is defined as belonging to the same orientation factor.
[0009]
The texture of a normal aluminum alloy is formed by these orientation factors. When these constituent ratios change, the plastic anisotropy (described later) of the plate material changes, and the press formability becomes good or bad.
There is an orientation distribution density as a quantitative evaluation method of these orientations. This is expressed as a ratio of the intensity of each orientation to a random orientation, and is obtained using a normal orientation X-ray diffraction method and measuring a complete positive map of at least three planes, and then using a crystal orientation distribution function [ See references 1 and 2 below]. Or based on data measured using electron beam diffraction, SEM (Scanning-Electron-Microscopy) -ECP (Electron-Channeling-Pattern), SEM-EBSP (Electron-Back-Scatterd-Pattern), etc. In addition, the orientation distribution density can be obtained using the crystal orientation distribution function. Further, since these orientation distributions change in the plate thickness direction, they are obtained by taking an average for some points in the plate thickness direction.
Reference 1: Book by Shinichi Nagashima, “Aggregation” (published by Maruzen Co., Ltd.) 1984, pages 8 to 44
Reference 2: Seminar of the Japan Institute of Metals, “Texture” (Japan Institute of Metals) 1981, P.3-7
[0010]
The present inventors examined the occurrence mechanism of ridging marks on Al-Mg-Si based alloy sheets having various texture changes, and studied the generation mechanism. As a result, it was found that Goss orientation, PP orientation, and Brass orientation with strong in-plane plastic anisotropy were criminals who generated ridging marks.
More specifically, the in-plane anisotropy of the r value (Rankford value) in the Goss orientation, PP orientation, and Brass orientation is very large compared to other orientations. In the orientation, when the direction is rotated by 20 ° from the rolling direction, and the Brass orientation is pulled in the direction rotated by 55 ° from the rolling direction, the thickness reduction hardly occurs, whereas other orientations cause the thickness reduction. It has been found that this remarkable difference in the plate thickness reduction rate causes surface irregularities (riding marks).
[0011]
Therefore, reducing the Goss azimuth, PP azimuth, and Brass azimuth is effective in suppressing ridging marks, but in particular the azimuth distribution density of the Goss azimuth is 3 or less, the azimuth distribution density of the PP azimuth is 3 or less, and the Brass azimuth When the azimuth distribution density is 3 or less, ridging marks can be suppressed. When the azimuth distribution density exceeds this, ridging marks are remarkably generated and the surface quality is deteriorated. More preferably, the orientation distribution density in the Goss orientation is 2 or less, the distribution density in the PP orientation is 2 or less, and the distribution density in the Brass orientation is 2 or less.
[0012]
Next, alloy elements of the Al—Mg—Si based alloy will be described.
(Mg, Si)
These elements form an aggregate (cluster) or intermediate phase having a Mg ₂ Si composition called a GP zone, and are important elements contributing to hardening by baking treatment. Also, it improves the work hardening characteristics of the plate material and plays the role of increasing the breaking limit during press molding. Furthermore, the Mg ₂ Si stable phase generated during the soaking process acts as a preferential nucleation site for the recrystallization orientation, and is an element that greatly affects the formation of the texture of the plate material.
If the Mg and Si contents are each less than 0.2 wt%, sufficient strength cannot be obtained during the baking process. If the Mg and Si contents exceed 1.5 wt%, the curing characteristics deteriorate during the baking process and coarse compounds are formed. It causes deterioration of moldability to become a starting point of fracture and further inhibits formation of a desired texture. More preferably, Mg: 0.8% or less, Si: 1.3% or less.
[0013]
(Mn, Cr, Fe, Zr, V, Ti)
Mn, Cr, Zr, V, and Ti form many fine precipitates by performing a long-time homogenizing heat treatment at a high temperature of 530 ° C. or more for 4 hours or more. The precipitate acts as a preferential nucleation site in the recrystallization orientation and is effective for obtaining a suitable texture. It is also effective for reducing the crystal grain size and increasing the limit of molding cracks. Furthermore, Mn and Cr are important elements that contribute to hardening by baking. However, if any of Mn, Cr, Zr, V, and Ti exceeds 1.0 wt%, 0.3 wt%, 0.3 wt%, 0.3 wt%, and 0.1 wt%, a coarse compound is formed. As a result, the moldability is remarkably deteriorated and the formation of a desired texture is inhibited.
Fe forms crystallized substances such as Al ₇ Cu ₂ Fe, Al ₁₂ (Fe, Mn) ₃ Cu ₁₂ , (Fe, Mn) Al ₆ , α-AlFeSi, β-AlFeSi, and the like, It works as a preferred nucleation site for recrystallization orientation and is effective for obtaining a suitable texture. However, if the content exceeds 1.0 wt%, the formation of a coarse compound becomes a starting point of destruction, so that the formability is remarkably deteriorated and the formation of a desired texture is inhibited.
Further, if the total of these elements is less than 0.01 wt%, the above effect is not obtained, and if it exceeds 1.5 wt%, the moldability is remarkably deteriorated because it becomes a starting point of fracture by molding a coarse compound, And it inhibits desired texture formation.
Particularly preferable ranges of these elements are Mn: 0.5 wt% or less, Cr: 0.2 wt% or less, Fe: 0.5 wt% or less, Zr: 0.2 wt% or less, V: 0.2 wt% or less. , Ti: 0.05 wt% or less.
[0014]
(Cu, Ag, Zn, Sn)
These elements are elements that promote the formation of aggregates (clusters) or intermediate phases of the Mg ₂ Si composition called GP zones. Further, Cu, Ag, and Zn have a function of increasing the curing rate during the baking process, and Sn has a function of suppressing room temperature aging in the stage before baking and promoting aging during baking. However, if the total of these elements is less than 0.01 wt%, the above effect is not obtained, while the contents of Cu, Ag, Zn, and Sn are 1.0 wt%, 0.2 wt%, 1.0 wt%,. If it exceeds 2 wt% or the total thereof exceeds 1.5%, a coarse compound is formed, which becomes a starting point of fracture, so that deterioration of moldability and formation of a desired texture are inhibited.
The particularly preferable ranges of these elements are Cu: 0.5 wt% or less, Ag: 0.1 wt% or less, Zn: 0.5 wt% or less, and Sn: 0.1 wt% or less.
[0015]
Next, suitable manufacturing conditions will be described.
After performing normal casting, homogenization heat treatment is performed. When transition metals such as Mn, Cr, Fe, Zr, and V are added, homogenization heat treatment is performed at a high temperature of 530 ° C or higher for 4 hours or longer. Thus, a lot of fine precipitates can be deposited. These precipitates are effective for obtaining a suitable texture, and are also effective for reducing the crystal grain size. Next, hot rolling is performed, and cold rolling is performed. The hot rolling start temperature exceeds 450 ° C., the hot rolling end temperature exceeds 360 ° C., and the final cold rolling rate is 85% or less. A desired texture can be obtained. In addition, you may anneal after completion | finish of hot rolling.
[0016]
Particularly important for obtaining a desired texture is a structure before solution treatment, from the Goss orientation to the Brass orientation, and the α orientation group to which the <110> axis belongs to the orientation parallel to the rolling surface normal. When Reference Document 3] develops, it causes development of Goss orientation, PP orientation, etc. after solution treatment. Therefore, it is necessary to suppress the development of the α orientation group before the solution treatment. The α orientation group develops during the hot rolling process, or develops as the rolling reduction increases during cold rolling. Therefore, in order to suppress the α direction group, the α direction group at the time of hot rolling is reduced by increasing the hot rolling end temperature and recrystallizing , and the cold rolling rate is reduced to reduce the α direction group at the time of cold rolling. Need to be reduced. For that purpose, the end temperature at the time of hot rolling is set to a temperature exceeding 360 ° C., and the final cold rolling rate is set to 85% or less . In addition, when hot rolling is started at a temperature exceeding 450 ° C. , recrystallization is likely to occur during rolling, and orientations other than the α orientation group formed during rolling are formed, and the α orientation group is reduced. As a result, the α orientation group in the structure before the solution treatment is weakened, the Goss, Brass, PP orientation after the solution treatment is reduced, and ridging marks are suppressed.
In addition, you may recrystallize by giving annealing after completion | finish of a hot rolling, and may reduce a hot rolling (alpha) direction group.
Finally, a solution treatment is performed, but it is desirable to maintain at a high temperature of 530 ° C or higher.
Reference 3: Kunio Ito, “Light Metal”, Volume 43 (1993), No. 5, pp. 285-293
[0017]
【Example】
Example 1
Al-0.6% Mg-1.0% Si alloy (hereinafter referred to as base alloy), Al-0.6% Mg-1.0% Si-0.1% Mn alloy (hereinafter referred to as Mn-added alloy) 3) alloy of Al-0.6% Mg-1.0% Si-0.1% Fe alloy (hereinafter referred to as Fe-added alloy) is cast by a usual method, and is 8 hours at 550 ° C. A homogenized heat treatment was applied. Thereafter, hot rolling (starting at 500 ° C.) gave a plate having a thickness of 500 mm to 10 to 1.5 mm. The end temperature of hot rolling was changed, the presence or absence of annealing after hot rolling (referred to as roughening in the present invention), and the cold rolling start plate pressure was changed to produce a 1 mm thick plate by cold rolling. Thereafter, a solution treatment was performed at 550 ° C. for 1 minute.
[0018]
It gave 15% tensile deformation for these plate members, the surface of the subsequent plate and painting, (with the property that ridging marks are found so conspicuous well after painting) that determine the presence or absence of ridging marks occur. Further, as an index of formability, an overhang forming test in a plane strain tension state was performed, and the crack limit height was measured.
For the measurement of the texture, the surface of the plate after solution treatment, 1/4 thickness, and the center portion of the plate thickness are subjected to normal X-ray diffraction using Cu as the target, tube voltage 50 kV, tube current Measure the (100), (110), (111) complete positive point map under the condition of 200 mA, and then calculate the orientation distribution density of each orientation for each thickness using the crystal orientation distribution function. The orientation distribution density of the entire plate was obtained.
Table 1 shows the results. In the material of the present invention, it is clear that generation of ridging marks is suppressed and the moldability is excellent.
[0019]
[Table 1]

[0020]
(Example 2)
Various alloys containing alloy components such as Mg, Si, Mn, Cr, Fe, Zr, V, and Ti shown in Table 2 were cast by an ordinary method and subjected to a homogenization treatment at 550 ° C. for 8 hours. Thereafter, hot rolling (starting temperature: 500 ° C.) was performed, and the end temperature was changed to obtain a plate having a thickness of 10 to 1.5 mm. And after making into a 1-mm-thick board by cold rolling, without performing roughening, the solution treatment for 1 minute was performed at 550 degreeC.
[0021]
[Table 2]

[0022]
About these board | plate materials, determination of the presence or absence of a ridging mark generation | occurrence | production, the measurement of the crack limit height by an overhang forming test, and the measurement of a texture were performed like Example 1. FIG.
Table 3 shows the results. In the material of the present invention, it is clear that generation of ridging marks is suppressed and the moldability is excellent.
[0023]
[Table 3]

[0024]
(Example 3)
Various alloys containing alloy components such as Mg, Si, Mn, Cr, Fe, Zr, V, Ti, Cu, Ag, Zn, and Sn shown in Table 4 were cast by a usual method, and 8 hours at 550 ° C. A homogenization treatment was performed. Thereafter, hot rolling (starting temperature: 500 ° C.) was performed, and the end temperature was changed to obtain a plate having a thickness of 10 to 1.5 mm. And after making into a 1-mm-thick board by cold rolling, without performing roughening, the solution treatment for 1 minute was performed at 550 degreeC .
[0025]
[Table 4]

[0026]
About these board | plate materials, determination of the presence or absence of a ridging mark generation | occurrence | production, the measurement of the crack limit height by an overhang forming test, and the measurement of a texture were performed like Example 1. FIG.
Table 5 shows the results. In the material of the present invention, it is clear that generation of ridging marks is suppressed and the moldability is excellent.
[0027]
[Table 5]

[0028]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the Al-Mg-Si type aluminum alloy plate for shaping | molding in which the ridging mark was suppressed can be obtained.

Claims (4)

  Mg: 0.2 to 1.5 wt%, Si: 0.2 to 1.5 wt%, Mn: 1.0 wt% or less, Cr: 0.3 wt% or less, Fe: 1.0 wt% or less, Contains Zr: 0.3 wt% or less, V: 0.3 wt% or less, Ti: 0.1 wt% or more in total of 0.01 to 1.5 wt%, the balance Al and unavoidable impurities An Al—Mg—Si-based aluminum alloy plate comprising: a texture having an orientation distribution density of Goss orientation of 3 or less, an orientation distribution density of PP orientation of 3 or less, and an orientation distribution density of Brass orientation of 3 or less. An Al—Mg—Si-based aluminum alloy plate for forming having excellent surface properties, characterized in that there is.   Mg: 0.2 to 1.5 wt%, Si: 0.2 to 1.5 wt%, Cu: 1.0 wt% or less, Ag: 0.2 wt% or less, Zn: 1.0 wt% or less, Sn: An Al-Mg-Si-based aluminum alloy plate containing one or more of 0.2 wt% or less in total of 0.01 to 1.5 wt%, the balance being Al and inevitable impurities, The Al texture for forming with excellent surface properties, characterized in that the orientation distribution density of Goss orientation is 3 or less, the orientation distribution density of PP orientation is 3 or less, and the orientation distribution density of Brass orientation is 3 or less. -Mg-Si based aluminum alloy plate. The aluminum alloy ingot having the composition described in claim 1 or 2 is subjected to hot rolling after homogenization, followed by cold rolling, and then subjected to solution treatment to form Al-Mg for forming. -In producing a Si-based aluminum alloy sheet, the homogenization treatment is performed at a temperature of 530 ° C or higher for 4 hours or longer, the hot rolling is started at a temperature exceeding 450 ° C, and finished at a temperature exceeding 360 ° C. 3. The Al—Mg—Si based aluminum alloy for forming with excellent surface properties according to claim 1 , wherein the cold rolling is performed so that a final cold rolling rate is 85% or less. A manufacturing method of a board. The manufacturing method of the Al-Mg-Si type aluminum alloy plate for shaping | molding excellent in the surface property described in Claim 3 characterized by performing annealing after hot rolling.