JP2018103228A - Al-Mg-Si BASED ALUMINUM ALLOY CAST PLATE AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-Mg-Si based aluminum alloy having sufficient bending workability and in which crack generation upon bending is suppressed, and a method for producing the same.SOLUTION: Provided is a method for producing an Al-Mg-Si based aluminum alloy cast plate by a twin roll cast method where, using a pair of confronted rotating rolls, a molten metal is fed therebetween and is solidified. The molten metal includes: Al of 90 mass% or more; Si of 0.3 to 2.0 mass%; and Mg of 0.2 to 3.0 mass%. Each roll is made of copper or a copper alloy, each peripheral speed of the pair of rotating rolls is 20 m/min or more and 150 m/min or less, and the pair of rotating rolls is pressed under 0.8 kN/mm or more and 2.0 kN/mm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an Al—Mg—Si based aluminum alloy cast plate and a method for producing the same.

  For example, an Al—Mg—Si based aluminum alloy typified by a 6000 based aluminum alloy has excellent age-hardening ability. For this reason, it is possible to improve the strength (for example, yield strength) by ensuring ageability by aging treatment at a relatively low temperature such as paint baking after molding, while ensuring moldability by reducing the yield strength during press molding and bending. have. In addition, the 6000 series aluminum alloy is superior in formability and corrosion resistance, although its strength does not reach that of the 2000 series alloy.

  In addition, Al—Mg—Si-based aluminum alloys, particularly 6000-series aluminum alloys, have a relatively small amount of alloy elements compared to other 5000-series aluminum alloys having a large amount of alloys such as Mg. Therefore, when these aluminum alloy sheet scraps are reused as an aluminum alloy melting material (melting raw material), it is easy to obtain an Al-Mg-Si aluminum alloy ingot similar to the original alloy sheet, etc. Is also excellent.

For this reason, it is an aluminum alloy attracting attention in many applications, for example, to reduce the weight of an automobile by using it as a plate material. Since an Al—Mg—Si-based aluminum alloy can be obtained at a low cost and relatively high productivity, a roll casting method is used to obtain an Al—Mg—Si-based aluminum alloy plate.
For example, Patent Document 1 discloses a method of obtaining an Al—Mg—Si-based aluminum alloy cast plate using a horizontal twin roll method. Non-Patent Document 1 discloses a method of obtaining an Al—Mg—Si based aluminum alloy cast plate in which internal cracks are suppressed by using a vertical twin roll cast method and optimizing the conditions. Yes.

JP-A-10-102178

"Effects of second phase particles on mechanical properties of Al-Mg-Si alloy sheets for automobiles" Kenji Tokuda 2007 Doctoral thesis (Tokyo Institute of Technology)

However, in the conventional casting methods including the methods disclosed in Patent Document 1 and Non-Patent Document 1, the obtained cast plate of Al—Mg—Si based aluminum alloy including 6000 based alloy is used as it is. When used (as it was after casting), there was a problem that cracks might occur on the surface during bending.
For example, in a conventional 6000 series alloy cast plate having a plate thickness of 10 mm or less, a crack (including microcracks) is not generated on the surface when a 180-degree bending test according to JIS Z 224198: 2006 is performed. It was extremely difficult.

  For this reason, the conventional Al-Mg-Si-based aluminum alloy cast plate cannot be subjected to bending with relatively severe processing conditions, and can be sufficiently bent Al-Mg-Si-based aluminum There was a need for an alloy cast plate.

  The embodiment according to the present invention aims to solve such a problem, and has a sufficient bending workability and casting of an Al—Mg—Si-based aluminum alloy that suppresses the generation of cracks during bending. It aims at providing a board and its manufacturing method.

Aspect 1 of the present invention is a method for producing an Al—Mg—Si based aluminum alloy cast plate by a twin roll casting method in which a pair of rotating rolls facing each other is used to supply molten metal between them and solidify them. Because
The molten metal contains 90% by mass or more of Al, 0.2 to 2.0% by mass of Si, and 0.2 to 3.0% by mass of Mg,
The roll is made of copper or a copper alloy, and the peripheral speed of each of the set of rotating rolls is 20 m / min or more and 150 m / min or less,
In the method for producing an Al—Mg—Si based aluminum alloy cast plate, the set of rotating rolls is pressed at 0.8 kN / mm or more and 2.0 kN / mm or less.

In aspect 2 of the present invention, the molten metal contains Si: 0.2 to 2.0 mass% and Mg: 0.2 to 3.0 mass%,
As needed, Fe: 1.0 mass% or less (not including 0 mass%), Mn: 1.4 mass% or less (not including 0 mass%), Cr: 0.35 mass% or less (0 mass) %), Zr: 0.3 mass% or less (not including 0 mass%), V: 0.3 mass% or less (not including 0 mass%), Ti: 0.25 mass% or less (0 Cu: 1.2 mass% or less (not including 0 mass%), Ag: 0.2 mass% or less (not including 0 mass%), Zn: 1.0 mass% or less (not including mass%) 0% by mass), Sn: 0.5% by mass or less (not including 0% by mass), Sc: 1.0% by mass or less (not including 0% by mass), B; 0.06% by mass or less 1 selected from the group consisting of (not including 0% by mass), Bi: not more than 1.5% by mass (not including 0% by mass) and Pb: not more than 2.0% by mass (not including 0% by mass). Seeds Further comprise two or more,
It is a manufacturing method of the Al-Mg-Si type aluminum alloy cast board of the aspect 1 which a remainder consists of Al and an unavoidable impurity.

  Aspect 3 of the present invention is the Al—Mg—Si based aluminum alloy cast plate according to aspect 2, wherein the molten metal satisfies one composition selected from 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy. It is a manufacturing method.

  Aspect 4 of the present invention contains at least one of Fe: 1.0 to 2.0 mass% and Cu: 1.0 to 1.2 mass%, and other elements are 6063 alloy, 6061 alloy, 6016 alloy. , 6022 alloy and 6111 alloy. The manufacturing method of the Al-Mg-Si type aluminum alloy cast plate of aspect 1 which satisfies the specification of one composition selected.

Aspect 5 of the present invention includes Si: 0.2 to 2.0 mass% and Mg: 0.2 to 3.0 mass%,
The thickness is 10 mm or less,
It is an Al—Mg—Si based aluminum alloy cast plate having no cracks on its surface after a 180 ° bending test in accordance with JIS Z 2248.

  A sixth aspect of the present invention is an automobile body sheet using the Al—Mg—Si based aluminum alloy cast plate according to the fifth aspect.

  According to the present invention, it is possible to provide an Al-Mg-Si-based aluminum alloy cast plate that has sufficient bending workability and suppresses the generation of cracks during bending, and a method for manufacturing the same.

FIG. 1 is a schematic cross-sectional view showing a twin-roll caster 100 used in a manufacturing method according to an embodiment of the present invention and a schematic partial enlarged cross-sectional view showing a meniscus 12a. FIG. 2 is a schematic cross-sectional view showing the bending test apparatus 200. FIG. 3 is a photograph showing an example of the surface observation result. FIG. 3A shows the surface observation result of Comparative Example 4-1, FIG. 3B shows the surface observation result of Comparative Example 4-2, and FIG. 3C shows the surface observation result of Example 4-3. It is a result.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating a specific direction and position (for example, “up”, “down”, “right”, “left” and other terms including those terms) are used as necessary. These terms are used for easy understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Moreover, the part of the same code | symbol which appears in several drawing shows the same part or member.

1. Manufacturing method of Al-Mg-Si based aluminum alloy cast plate As a result of intensive studies, the present inventors have found that 90% by mass or more of Al, 0.2 to 2.0% by mass of Si, and 0.2 to 3. When manufacturing an Al-Mg-Si aluminum alloy cast plate containing 0% by mass of Mg, the roll material, the peripheral speed of the roll, and the pressing force applied to the roll are properly used by using the twin roll casting method. Al-Mg-Si-based Al-Mg-Si-based aluminum alloy can be controlled by casting within a range to suppress the occurrence of cracks (including microcracks) on the surface when bending is performed. It has been found that an aluminum alloy cast plate can be obtained.

Below, the casting apparatus used for the manufacturing method of the Al-Mg-Si-type aluminum alloy cast plate which concerns on embodiment of this invention is demonstrated first.
FIG. 1 is a schematic cross-sectional view showing a twin-roll caster 100 used in a manufacturing method according to an embodiment of the present invention and a schematic partial enlarged cross-sectional view showing a meniscus 12a.
The twin roll caster 100 has a roll 1A and a set of rolls 1B. Roll 1A and roll 1B are spaced apart and rotate in the directions of arrow A and arrow B, respectively. The molten metal 10 supplied to the gap (casting cavity) between the rolls 1A and 1B is brought into contact with the rotating rolls 1A and 1B, cooled, and solidification proceeds. It progresses and it cools further and the Al-Mg-Si type aluminum alloy cast plate 12 is formed. In the embodiment shown in FIG. 1, the cooling after the solidified part (including the case where the solidified part is included in the inside) is separated from the rolls 1 </ b> A and 1 </ b> B is air-cooled. Other cooling methods may be used for cooling.

  Solidification forms a meniscus 12a in the vicinity of the portion where the molten metal 10 comes into contact with the roll 1A or 1B and the nozzle 3 (including when the molten metal 10 comes into contact with the release agent). As the meniscus 12a moves downward along the roll 1A or 1B, cooling proceeds, and a solidified portion (an outer portion of the Al-Mg-Si-based aluminum alloy cast plate 12 finally obtained) is formed. Then, in the process in which the solidified portion advances downward by the rotation of the roll 1A and the roll 1B, the entire cross section perpendicular to the casting direction is solidified, and the Al—Mg—Si based aluminum cast plate 12 is formed.

It is preferable to use the nozzle 3 to supply the molten metal 10 between the roll 1A and the roll 1B through the nozzle 3 in a state where the liquid level (molten surface) 10a of the molten metal 10 is formed in the nozzle 3. The molten metal generates a hydrostatic pressure of a certain size, can suppress fluctuations in the shape of the meniscus 12a, and can obtain more stable casting conditions. The liquid level 10a is preferably 5 mm, more preferably 10 mm, and is located above the tip of the meniscus 12a (the upper end of the meniscus 12a in FIG. 1).
The shape of the meniscus 12a shown in FIG. 1 is merely an example, and the meniscus 12a may have a different shape depending on casting conditions such as the height of the liquid surface of the molten metal. Further, the shape of the meniscus 12a may fluctuate periodically or aperiodically due to fluctuations in casting conditions such as the height of the melt surface.
The nozzle 3 may be made of a refractory material.
When supplying the molten metal 10 to the twin roll caster 100. The molten metal 10 is preferably at a temperature 10 to 50 ° C. higher than the liquidus temperature. Thereby, more stable casting can be performed.

A twin roll caster (a twin roll casting apparatus) 100 shown in FIG. 1 is a vertical casting apparatus. That is, the roll 1A and the roll 1B are arranged side by side in the horizontal direction, and the molten metal 10 is normally supplied between the roll 1A and the roll 1B from above. The vertical casting apparatus is preferable because it can easily pour molten metal between rolls and it is easy to increase the casting speed.
However, the present invention is not limited to this. For example, a horizontal roll caster in which two rolls are arranged side by side in the vertical direction and hot water is poured between the rolls from the horizontal direction may be used. An inclined casting machine in which the two rolls are arranged in an angled direction that is neither horizontal nor vertical may be used.

Moreover, in the twin roll caster (double roll type casting apparatus) 100 shown in FIG. 1, the diameter of the roll 1A and the roll 1B is the same. Thereby, the peripheral speed of two rolls can be made the same comparatively easily. However, the present invention is not limited to this, and the diameter of one roll may be larger than the diameter of the other roll.
Next, the details of the casting conditions of the Al—Mg—Si based aluminum alloy cast plate according to the embodiment of the present invention will be described.

(1) Roll material The roll 1A and the roll 1B are made of copper or a copper alloy. Thereby, high heat transfer characteristics between the molten metal 10 and the roll 1A or the roll 1B can be obtained, and the molten metal 10 can be solidified at a sufficiently high cooling rate, and the resulting Al—Mg—Si based aluminum casting can be obtained. It is possible to suppress the occurrence of cracks on the surface of the plate 12 after bending.
Here, the copper alloy means an alloy containing 50% or more of copper by mass ratio. Preferably, copper is contained 90% or more by mass ratio, more preferably, copper is contained 98% or more by mass ratio. Thereby, sufficient heat transfer characteristics can be obtained more reliably. As such a preferable copper alloy, Cu ≧ 98% by mass, Cr: 0.05 to 1.5% by mass and Zr: 0.03 to 0.8% by mass, the balance being inevitable impurities, CCM- A alloy and CCM-B alloy can be illustrated.

  In the present specification, “the roll is made of copper or a copper alloy” means that a portion of the roll surface that contacts the molten metal 10 is formed of copper or a copper alloy, and does not contact the molten metal. It is a concept including a roll in which a portion (inside) is formed of a material other than copper or a copper alloy and a roll having a hollow portion inside.

(2) Roll peripheral speed As described above, the roll 1A and the roll 1B rotate in the directions of the arrow A and the arrow B, respectively. And the peripheral speed of the roll 1A and the roll 1B is 20 m / min or more and 150 m / min or less. Preferably, the peripheral speeds of roll 1A and roll 1B are the same.
In order to avoid the occurrence of surface cracks after bending, the roll peripheral speed is usually slowed down, for example, 10 m / min. However, the inventor made copper or a copper alloy as described above, and, as will be described in detail below, a pair of rolls (rolls 1A and 1B) is 0.8 kN / mm or more, By pressing at a speed of 2.0 kN / mm or less and a roll peripheral speed of 20 m / min or more, the thickness of the solidified layer at the time of casting is stabilized, and the load fluctuation on the roll is reduced. It has been found that the occurrence of surface cracks can be suppressed. Thus, being able to cast at a roll peripheral speed of 20 m / min or more means that high-speed twin-roll casting is possible, and high productivity can be realized.

  On the other hand, when the roll peripheral speed exceeds 150 m / min, it becomes difficult to maintain the contact state between the melt and the roll uniformly due to the melt head pressure. For this reason, in order to further increase the molten metal head pressure, it is necessary to increase the wall surface height of the nozzle or apply a gas pressure, which is not practical because the manufacturing apparatus becomes large and complicated.

(3) Pressing the Roll A pair of rolls (double rolls) composed of the rolls 1 </ b> A and 1 </ b> B is pressed as indicated by an arrow P in FIG. 1. More specifically, the pair of rolls are pressed in a direction in which the interval between the rolls becomes narrow. The pressing force is 0.8 kN / mm or more and 2.0 kN / mm or less. The pressing force is obtained by dividing the load applied to the roll by the length of the roll (width, the length in the direction perpendicular to the paper surface of FIG. 1).
When the pressing force is 0.8 kN / mm or more, the shape of the solidified part is stabilized at a roll peripheral speed of 20 m / min or more, and the obtained Al—Mg—Si based aluminum alloy cast plate is bent. It is possible to suppress the occurrence of cracks on the surface.

  On the other hand, when the pressing force exceeds 2.0 kN / mm, the roll surface is roughened in a short time during casting, and the unevenness is transferred to the surface of the obtained Al—Mg—Si-based aluminum alloy cast plate. Due to the unevenness, surface cracks occur during bending. For example, when the roll surface after casting a 6022 alloy plate at a roll peripheral speed of 60 m / min is compared, when the pressing force is 2.0 kN / mm, there is almost no roughness on the roll surface, whereas the pressing force is 2. In the case of 5 kN / mm, it has been confirmed that the roll surface is rough and uneven in a short time.

  In addition, you may perform the press of a roll using known apparatuses, such as a spring or a damper, for example. In FIG. 1, the pressing force P is applied to both the roll 1A and the roll 1B. However, the present invention is not limited to this. For example, one of the rotation axes of the roll 1A and the roll 1B is set in the horizontal direction in FIG. It may be fixed so as not to move, and the pressing force P may be applied only to the other of the rolls 1A and 1B.

(4) Alloy composition The Al-Mg-Si-based aluminum alloy cast plate according to the embodiment of the present invention has 90% by mass or more of Al, 0.2 to 2.0% by mass of Si, and 0.2 to 3%. 0.0% by mass of Mg, preferably 95% by mass or more of Al, 0.2 to 2.0% by mass of Si, and 0.2 to 2.0% by mass of Mg.
In one preferred embodiment, the balance is inevitable impurities.
In another preferred embodiment, in addition to inevitable impurities, any one or more elements that do not impair castability may be included. That is, when the cast material cast under the casting conditions satisfying the conditions defined in “(1) Roll material”, “(2) Roll peripheral speed” and “(3) Roll pressing” is bent on the surface. As long as an Al—Mg—Si based aluminum alloy cast plate can be obtained without causing cracks, the balance may contain any one or more elements other than inevitable impurities.

As an alloy that satisfies such an alloy composition and is widely used, there is a 6000 series alloy defined by the JIS standard and the American AA standard.
The 6000 series alloys are 6101 alloy, 6061 alloy and 6082 alloy whose composition is defined in Japanese Industrial Standard JIS H 4000: 2014, and 6005A alloy, 6005C alloy, 6060 whose composition is defined in JIS H 4040: 2015. Alloy, 6262 alloy, 6063 alloy and 6181 alloy, and 6463 alloy whose composition is defined in JIS H 4080: 2015. In addition to the JIS standard, for example, AA standard 6016 alloy, 6022 alloy and 6111 alloy are also included in the 6000 series alloy.

There are several definitions for the composition range that defines the entire 6000 series alloy. In this specification, the composition range of the 6000 series alloy is defined as follows.
Si: 0.2-2.0 mass% and Mg: 0.2-3.0 mass%,
It is allowed to contain one or more selected from the following as required,
Fe: 1.0% by mass or less (excluding 0% by mass)
Mn: 1.4% by mass or less (excluding 0% by mass)
Cr: 0.35 mass% or less (excluding 0 mass%)
Zr: 0.3% by mass or less (excluding 0% by mass)
V: 0.3% by mass or less (excluding 0% by mass)
Ti: 0.25 mass% or less (excluding 0 mass%)
Cu: 1.2% by mass or less (excluding 0% by mass)
Ag: 0.2% by mass or less (excluding 0% by mass)
Zn: 1.0% by mass or less (excluding 0% by mass)
Sn: 0.5 mass% or less (excluding 0 mass%)
Sc: 1.0 mass% or less (excluding 0 mass%)
B: 0.06% by mass or less (excluding 0% by mass)
Bi: 1.5% by mass or less (excluding 0% by mass)
Pb: 2.0% by mass or less (excluding 0% by mass)
The balance consists of Al and inevitable impurities.

  Among the 6000 series alloys, considering the wide range of uses, 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy are preferable.

Further, as an improved alloy of 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy, it contains at least one of Fe: 1.0 to 2.0 mass% and Cu: 1.0 to 1.2 mass%. , Other elements (that is, when Fe is contained in an amount of 1.0 to 2.0% by mass, an element other than Fe, and when Cu is contained in an amount of 1.0 to 1.2% by mass, an element other than Cu, Fe is added. In the case of containing 1.0 to 2.0 mass% and containing 1.0 to 1.2 mass% of Cu, elements other than Fe and Cu) are 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy or 6111 alloy. An alloy that satisfies the compositional standard can also be cited as a preferred composition.
It has the effect which can improve the ductility after roll cast by containing 1.0-2.0 mass% of Fe, and intensity | strength can be improved by containing 1.0-1.2 mass% of Cu.

  In addition, since the Al-Mg-Si type aluminum alloy cast plate 12 which concerns on embodiment of this invention has the composition mentioned above, the molten metal 10 has a composition substantially the same as said composition.

2. Al—Mg—Si-based aluminum alloy cast plate The Al—Mg—Si-based aluminum alloy cast plate according to the embodiment of the present invention has a composition defined in “(4) Alloy composition” described above. Moreover, even if the 180 degree | times bending process test based on JISZ2248: 2006 is done, a crack (a micro crack is included) is not produced on the surface.
For conventional 6000 series alloy plates with a thickness of 10 mm or less that have many uses, cast plates that do not crack on the surface even if they are bent by 180 degrees (without heat treatment after casting, that is, as cast Cast sheet in which cracks do not occur on the surface even when the bending test is performed in the above state), the Al—Mg—Si based aluminum alloy cast plate according to the embodiment of the present invention has a plate thickness of 10 mm. In the following, even if a 180 degree bending test based on JIS Z 2248: 2006 is performed, the surface does not crack.
Such an Al—Mg—Si based aluminum alloy cast plate according to the embodiment of the present invention can be used for various members such as a body sheet of an automobile.
In particular, a 6000 series aluminum alloy plate obtained by thin-casting a 6000 series aluminum alloy, particularly 6022 aluminum alloy by the above-described twin roll casting method, and rolling after casting, is a body sheet for automobiles (inner plates, outer plates, ceilings). ) Can be suitably used.

Example 1
1. Sample Preparation An Al—Mg—Si based aluminum alloy cast plate sample having the components shown in Table 1 was prepared using a roll caster 100 schematically shown in FIG.
As the roll 1A and the roll 1B, rolls made of a copper alloy CCM-A having a diameter of 300 mm and a width of 50 mm were used. The roll peripheral speeds of the roll 1A and the roll 1B were the same, and as shown in Table 2, they were 30 m / min or 90 m / min. Further, as shown in Table 2, a pressing force P of 0.2 kN / mm to 2.0 kN / mm was applied to the roll. The rotation axis of the roll 1B is fixed so as not to move in the lateral direction, and the pressing force P is applied only to the roll 1A.
The distance between the roll 1A and the roll 1B was adjusted so that the plate thickness t of the obtained sample was 3 mm.

  A nozzle having a height of 200 mm and a length in the roll width direction of 50 mm was used. Molten metal 10 having a temperature 10 to 50 ° C. higher than the liquidus temperature was poured into the nozzle 3. The molten metal 10 was poured so that the molten metal level 10a in the nozzle 3 was 50 mm or more from the tip of the meniscus 12a.

  As a result, a cast material having a width of 50 mm and a thickness of 3 mm was obtained for each sample.

2. Bending test and surface observation About the obtained sample, the 180 degree | times bending test based on JISZ2248: 2006 was done. FIG. 2 is a schematic cross-sectional view showing the bending test apparatus 200. The obtained cast material was cut to obtain a No. 1 test piece having a length of 80 mm, a width of 50 mm, and a thickness (t) of 3 mm. The distance between the support 22 and the support 23 was 30 mm. The inner radius r of the front end portion of the metal fitting 21 was 10 mm.
Then, after pressing the metal fitting 21 in the direction of arrow F to 170 ° and bending it to 170 °, both ends of the test piece are pressed against each other with a scissors having a thickness of 20 mm, which is twice the inner radius r, and bent to 180 °. It was.

About the test piece after a bending test, the surface part which was the outer side at the time of bending was observed with the naked eye. The surface observation results are shown in Table 2. “X” indicates that a clear crack was observed, “△” indicates that a gloss unevenness or vertical streak corresponding to a microcrack was observed, and no crack was observed. Was set as “◯” and “○” was set as pass.
FIG. 3 is a photograph showing an example of the surface observation result. FIG. 3A shows the surface observation result of Comparative Example 4-1, FIG. 3B shows the surface observation result of Comparative Example 4-2, and FIG. 3C shows the surface observation result of Example 4-3. It is a result.

As can be seen from Table 2, the sample of the example in which the peripheral speed of the roll is 20 m / min or more and 150 m / min or less, and the pressing force of the roll is 0.8 kN / mm or more and 2.0 kN / mm or less. Also showed good results with no cracks on the surface after the bending test.
On the other hand, the comparative example does not satisfy at least one of the peripheral speed of the roll being 20 m / min or more and 150 m / min or less and the pressing force of the roll being 0.8 kN / mm or more and 2.0 kN / mm or less. All the samples had cracks or microcracks on the surface after the bending test.

Example 2
An alloy obtained by further adding 0.2 to 1.0 mass% of Fe to 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy of Example 1 described in Table 2, and further Cu to 0.202 alloy A sample of an alloy added with ˜1.0 mass% was prepared.
The composition of each alloy is such that the remaining Al is reduced by the amount of Fe or Cu added. For example, in an alloy sample in which 0.2 mass% Fe is added to 6063 alloy (described as “6063 + 0.2% Fe” in the table), the Fe content is 0.40 mass%, and only the increment of Fe The remaining Al is reduced, and the other elements Si, Cu, Mn, Mg, Cr, Zn, and Ti are substantially the same as the values shown in Table 2.

A cast material having the same size (length 80 mm, width 50 mm, thickness 3 mm) as in Example 1 was obtained by the method described in “1. Sample preparation” in Example 1 except that the alloy composition was different.
And the bending test and surface observation were performed by the method as described in "2. Bending test and surface observation" of Example 1 using the obtained cast material.
The surface observation results are shown in Tables 3-8.
Tables 3 to 7 show the surface observation results of alloy samples obtained by adding 0.2 to 1.0% by mass of Fe to 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy, respectively. The surface observation result of the sample of the alloy which added 0.2-1.0 mass% of Cu further to 6022 alloy is shown.

As can be seen from Tables 3 to 8, a sample in which the peripheral speed of the roll is 20 m / min to 150 m / min and the pressing force of the roll is 0.8 kN / mm to 2.0 kN / mm (Example) All of the samples showed good results with no cracks on the surface after the bending test.
On the other hand, a sample that does not satisfy at least one of the peripheral speed of the roll being 20 m / min or more and 150 m / min or less and the pressing force of the roll being 0.8 kN / mm or more and 2.0 kN / mm or less ( All of the comparative sample samples had cracks or microcracks on the surface after the bending test.

DESCRIPTION OF SYMBOLS 1A, 1B Roll 3 Nozzle 10 Molten metal 10a Molten liquid surface 12 Al-Mg-Si type aluminum alloy cast plate 12a Meniscus 21 Bracket 23 Support part 30 Sample 100 Twin roll caster 200 Bending test apparatus

Claims (6)

A method for producing an Al—Mg—Si based aluminum alloy cast plate by a twin roll casting method in which a pair of rotating rolls facing each other is used to supply and solidify a molten metal between them,
The molten metal contains 90% by mass or more of Al, 0.2 to 2.0% by mass of Si, and 0.2 to 3.0% by mass of Mg,
The roll is made of copper or a copper alloy, and the peripheral speed of each of the set of rotating rolls is 20 m / min or more and 150 m / min or less,
The manufacturing method of the Al-Mg-Si type aluminum alloy cast board by which the said 1 set of rotating roll is pressed by 0.8 kN / mm or more and 2.0 kN / mm or less. The molten metal contains Si: 0.2-2.0 mass% and Mg: 0.2-3.0 mass%,
As needed, Fe: 1.0 mass% or less (not including 0 mass%), Mn: 1.4 mass% or less (not including 0 mass%), Cr: 0.35 mass% or less (0 mass) %), Zr: 0.3 mass% or less (not including 0 mass%), V: 0.3 mass% or less (not including 0 mass%), Ti: 0.25 mass% or less (0 Cu: 1.2 mass% or less (not including 0 mass%), Ag: 0.2 mass% or less (not including 0 mass%), Zn: 1.0 mass% or less (not including mass%) 0% by mass), Sn: 0.5% by mass or less (not including 0% by mass), Sc: 1.0% by mass or less (not including 0% by mass), B: 0.06% by mass or less 1 selected from the group consisting of (not including 0% by mass), Bi: not more than 1.5% by mass (not including 0% by mass) and Pb: not more than 2.0% by mass (not including 0% by mass). Seeds Further comprise two or more,
The method for producing an Al-Mg-Si-based aluminum alloy cast plate according to claim 1, wherein the balance is made of Al and inevitable impurities.   3. The method for producing an Al—Mg—Si based aluminum alloy cast plate according to claim 2, wherein the molten metal satisfies one composition selected from 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy.   Fe: at least one of 1.0 to 2.0 mass% and Cu: 1.0 to 1.2 mass%, and other elements than 6063 alloy, 6061 alloy, 6016 alloy, 6022 alloy and 6111 alloy The manufacturing method of the Al-Mg-Si type aluminum alloy cast plate of Claim 1 which satisfies the specification of one selected composition. Si: 0.2-2.0 mass% and Mg: 0.2-3.0 mass%,
The thickness is 10 mm or less,
An Al—Mg—Si based aluminum alloy cast plate having no cracks on its surface after a 180 ° bending test in accordance with JIS Z 2248.   An automobile body sheet using the Al-Mg-Si-based aluminum alloy cast plate according to claim 5.

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