JPH09164453A - Method for continuously casting aluminum alloy strip and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus, in which a hot-rolling and a cold-rolling processes, etc., are reduced and an aluminum alloy strip having suitable diameter of crystallized grains and smooth surface characteristic can be produced, by using a twin roll type continuous caster provided with a pair of cooling rolls rotated in mutually reverse direction and side weirs being in sliding contact with both end surfaces of the cooling rolls. SOLUTION: Strip is cast by the twin roll type continuous caster by using the molten aluminum alloy composed of 2.1-4.5wt.% Mn, 0.8-1.5wt.% Mg, 0.1-0.4wt.% Si and the balance Al with inevitable impurities. As the cooling rolls 1, 1' in the twin roll type continuous caster, the one provided with raggedness of 20-60μm Rmax surface roughness on the surface is used to prevent fine crack on the cast strip surface and oozing-out of the molten metal in the inner part.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明はアルミニウム缶の胴
材に適用して好適なアルミニウム合金圧延板とその製造
方法および製造装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolled aluminum alloy plate suitable for use as a body material for aluminum cans, a manufacturing method thereof, and a manufacturing apparatus thereof.

【０００２】[0002]

【従来の技術】従来、缶胴用のアルミニウム合金として
はＡｌ−Ｍｎ系の３００４合金（ＪＩＳ呼称）が用いら
れて来た。この合金は半連続鋳造法であるＤＣ（Direct
Chill) 法によって溶湯から厚さ６００mmの鋳塊をつく
り、これに熱間圧延、冷間圧延を施して厚さ１mm以下の
缶用薄板としていた。ＤＣ鋳造法では鋳造時の鋳塊厚が
６００mmと厚いため、熱間圧延、冷間圧延に多くのエネ
ルギーを必要とし、コスト高を招いていた。2. Description of the Related Art Conventionally, an Al—Mn-based 3004 alloy (JIS name) has been used as an aluminum alloy for a can body. This alloy is a DC (Direct) semi-continuous casting method.
A 600 mm-thick ingot was made from the molten metal by the Chill method, and hot-rolled and cold-rolled to obtain a thin plate for a can having a thickness of 1 mm or less. Since the ingot thickness at the time of casting is as thick as 600 mm in the DC casting method, much energy is required for hot rolling and cold rolling, resulting in high cost.

【０００３】近年、厚さ３〜１５mmの板を直接鋳造する
連続鋳造圧延法によるアルミニウム合金板の製造が報告
されているが、これらは純Ａｌ系の１１００合金やＡｌ
にＭｎ，Ｚｒを添加した耐熱性アルミニウム合金につい
てのものであり、缶用アルミニウム合金については依然
としてＤＣ鋳造に依存している。In recent years, production of aluminum alloy sheets by a continuous casting and rolling method in which a sheet having a thickness of 3 to 15 mm is directly cast has been reported. These are pure Al-based 1100 alloy and Al.
It is a heat-resistant aluminum alloy to which Mn and Zr are added, and an aluminum alloy for a can still depends on DC casting.

【０００４】[0004]

【発明が解決しようとする課題】前述のようにＤＣ法に
より得られる鋳塊は厚さが６００mmと厚いため、それを
薄板とする際には多くの圧延工程を必要とする。そこで
双ドラム式連続鋳造機を用い、厚さ１．５〜５．０mmの
薄板を直接鋳造して、熱延工程および冷延工程の一部を
省略し、コスト低減を図ることが考えられた。Since the ingot obtained by the DC method has a large thickness of 600 mm as described above, many rolling steps are required to form it into a thin plate. Therefore, it was considered to use a twin-drum type continuous casting machine to directly cast a thin plate having a thickness of 1.5 to 5.0 mm and omit a part of the hot rolling process and the cold rolling process to reduce the cost. .

【０００５】しかしながら、例えば３００４合金を双ド
ラム式連続鋳造機を用いて鋳造する場合、板材を缶加工
する際に工具への焼付きを防止する働きがある鋳片表面
晶出物が有効な大きさ（約２μm ）に満たない。また鋳
片表面に微細割れや内部溶湯のしみ出しが生じ板材の品
質低下の原因となっていた。However, for example, when 3004 alloy is cast using a twin-drum type continuous casting machine, a slab surface crystallized substance that has a function of preventing seizure on a tool during can processing of a plate material is an effective size. (Less than about 2 μm). In addition, fine cracks and exudation of the internal molten metal occurred on the surface of the slab, which was a cause of deterioration of the quality of the plate material.

【０００６】本発明は、双ドラム式連続鋳造機を用いて
薄板を鋳造することによって熱延および冷延工程等を減
らし、かつ、晶出物の粒径が適切で、平滑な表面性状を
もつアルミニウム合金の薄板とその製造方法と装置を提
供することを課題としている。The present invention reduces the hot rolling and cold rolling steps by casting a thin plate using a twin-drum type continuous casting machine, has an appropriate grain size of crystallized substances, and has a smooth surface texture. An object of the present invention is to provide a thin plate of aluminum alloy and a method and apparatus for manufacturing the same.

【０００７】[0007]

【課題を解決するための手段】本発明は、前記課題を解
決するため、連続鋳造により薄板を鋳造するアルミニウ
ム合金の組成をＭｎ ２．１〜４．５％，Ｍｇ ０．８
〜１．５％，Ｓｉ ０．１〜０．４％で残部がＡｌおよ
び不可避的不純物とする。双ドラム式連続鋳造機での鋳
造において鋳片表面部の凝固時冷却速度は１０³ k/s 程
度となる。In order to solve the above-mentioned problems, the present invention has a composition of an aluminum alloy for casting a thin plate by continuous casting of Mn 2.1-4.5%, Mg 0.8
.About.1.5%, Si 0.1.about.0.4%, and balance Al and unavoidable impurities. In casting with a twin-drum type continuous casting machine, the cooling rate of the surface of the slab during solidification is about 10 ³ k / s.

【０００８】これはＤＣ法鋳片の１００〜１０００倍の
冷却速度であり、この結果同じ３００４合金を鋳造した
場合、組織中の晶出物粒径はＤＣ法鋳片で約２．０μm
であるのに対し双ドラム式連続鋳造機鋳片では約１．２
μm と微細になる。この晶出物は圧延板を缶成形加工す
る際、工具との焼付きを防止する働きがあるが、双ドラ
ム式連続鋳造機での鋳片の晶出物粒径１．２μm ではこ
の働きが有効に作用しない。This is a cooling rate 100 to 1000 times that of the DC slab, and as a result, when the same 3004 alloy is cast, the crystallized grain size in the structure is about 2.0 μm for the DC slab.
On the other hand, twin drum type continuous casting machine cast slab is about 1.2
It becomes as fine as μm. This crystallized product has a function of preventing seizure with a tool when forming a rolled plate into a can, but this function is obtained when the crystallized product grain size of the slab is 1.2 μm in the twin drum type continuous casting machine. Does not work effectively.

【０００９】そこで晶出物の主な構成元素であるＭｎの
含有量を３００４合金の約１％から２．１％以上に増加
して晶出物の体積を増やし粒径をＤＣ鋳片中の晶出物並
（２．０μm ）とすれば焼付きの防止が可能である。し
かし、５．０％を超えると鋳片中心付近の低冷却速度域
に直径１００μm 以上の巨大金属間化合物が晶出し板材
の強度低下の原因となるためＭｎ含有量を２．１％〜
４．５％とする必要がある。Therefore, the content of Mn, which is the main constituent element of the crystallized product, is increased from about 1% of the 3004 alloy to 2.1% or more to increase the volume of the crystallized product and the grain size in the DC slab. The seizure can be prevented by using a crystallized product (2.0 μm). However, if it exceeds 5.0%, a giant intermetallic compound having a diameter of 100 μm or more causes a decrease in the strength of the crystallized sheet material in the low cooling rate region near the center of the slab, so the Mn content is 2.1% to
It should be 4.5%.

【００１０】添加元素のうちＳｉは晶出する金属間化合
物の構成元素となり、Ｓｉを添加しない場合晶出する金
属間化合物に比べ、晶出物の硬度を高める。この硬い晶
出物が板材の缶成形加工時の工具との焼付き防止の働き
を担う。またＭｇは母相中へ固溶する事により板材の強
度を高める働きがある。Among the additional elements, Si becomes a constituent element of the crystallized intermetallic compound, and increases the hardness of the crystallized material as compared with the intermetallic compound which crystallizes when Si is not added. This hard crystallized substance plays a role of preventing seizure with a tool during can forming processing of a plate material. Further, Mg has a function of enhancing the strength of the plate material by forming a solid solution in the matrix phase.

【００１１】しかしながらＳｉ，Ｍｇを過剰に添加する
とこれらの元素が結びついた化合物が晶出、あるいは析
出する。この化合物は非常に脆く板材の強度低下の原因
となるためＭｇ，Ｓｉの含有量はそれぞれ１．５％，
０．４％以下とする事が望ましい。However, if Si and Mg are excessively added, a compound in which these elements are combined crystallizes or precipitates. Since this compound is very brittle and causes a decrease in strength of the plate material, the contents of Mg and Si are 1.5%,
It is desirable to set it to 0.4% or less.

【００１２】一方、鋳片表面の微細割れおよび内部溶湯
のしみ出しは、ドラム表面粗さの影響によって生じる凝
固初期の結晶粒成長形態が原因となって生ずる。凝固
時、ドラム表面に発生する核の分布は、ドラム表面の凹
凸の分布に対応する。On the other hand, the fine cracks on the surface of the cast slab and the exudation of the internal molten metal are caused by the crystal grain growth morphology in the initial stage of solidification caused by the influence of the surface roughness of the drum. The distribution of nuclei generated on the drum surface during solidification corresponds to the uneven distribution on the drum surface.

【００１３】ドラム表面粗さ（Ｒmax ，以下同じ）が２
０μm 以下の場合、ドラム表面の小さい凹凸は核発生に
ほとんど影響を与えず、局所的に発生した核が成長する
ため不均一凝固となり表面微細割れを生じる。一方、６
０μm 以上の粗さのドラム表面では、表面凸部にそれぞ
れ核が発生、成長するため均一凝固となる。Drum surface roughness (Rmax, same below) is 2
In the case of 0 μm or less, small irregularities on the drum surface have almost no effect on nucleation, and locally generated nuclei grow, resulting in non-uniform solidification and surface microcracks. On the other hand, 6
On the surface of the drum having a roughness of 0 μm or more, nuclei are generated and grown on the convex portions of the surface of the drum, which results in uniform solidification.

【００１４】しかしながら凸部の数の密度が低いため、
核発生、成長した結晶粒は粗大に成長し結晶粒界に多く
の溶質元素が未凝固で集まる。この結晶粒のネットワー
クが凝固収縮すると粒界の未凝固溶質元素は絞り出され
鋳片表面のしみ出しとなる。ドラム表面粗さを２０〜６
０μm とすれば表面凹凸は均一な凝固核発生に有効に作
用し、なおかつ、凸部の適当な数の密度によって結晶粒
も微細となり、未凝固溶質元素の粒界への濃化が弱まる
ので、凝固収縮時の内部溶湯しみ出しも生じない。However, since the density of the number of convex portions is low,
Nucleated and grown crystal grains grow coarsely, and many solute elements gather in the crystal grain boundaries without solidification. When this network of crystal grains solidifies and shrinks, the unsolidified solute elements at the grain boundaries are squeezed out and the surface of the slab is exuded. Drum surface roughness of 20-6
When it is 0 μm, the surface irregularities effectively act to generate uniform solidification nuclei, and the crystal grains become finer due to the appropriate number of densities of the convex portions, and the concentration of unsolidified solute elements in the grain boundaries is weakened. No internal molten metal oozes out during solidification shrinkage.

【００１５】このように、本発明では、前記した合金組
成のアルミニウム合金を用いて双ドラム式連続鋳造機に
よりアルミニウム合金の薄板を連続鋳造する場合、ドラ
ム表面にＲmax が２０〜６０μm の粗さの凹凸を設けた
冷却ドラムを用いて、鋳造される鋳片表面の微細割れお
よび内部溶湯のしみ出しを防止する。As described above, according to the present invention, when the aluminum alloy thin plate is continuously cast by the twin-drum type continuous casting machine using the aluminum alloy having the above-mentioned alloy composition, the drum surface has a roughness Rmax of 20 to 60 μm. By using a cooling drum provided with irregularities, fine cracks on the surface of the cast slab and exudation of the internal molten metal are prevented.

【００１６】また、鋳片に熱処理を施すと固溶Ｍｎの析
出、およびオストワルド成長によって晶出物の粒径が増
大する。粒成長は熱処理温度が高い程著しく、６００℃
で８時間の熱処理を施せば０．２〜０．５μm 粒径が増
大する。しかしこれ以上高温では液相の発生および板材
のクリープ変形が生じるため熱処理温度は６００℃以下
に限定される。When heat treatment is applied to the cast slab, the grain size of the crystallized product increases due to the precipitation of solid solution Mn and the Ostwald ripening. Grain growth is more remarkable at higher heat treatment temperature, 600 ° C
If the heat treatment is performed for 8 hours, the grain size of 0.2 to 0.5 μm increases. However, if the temperature is higher than this, the liquid phase is generated and the plate material is creep-deformed, so that the heat treatment temperature is limited to 600 ° C. or lower.

【００１７】[0017]

【発明の実施の形態】以下、本発明によるアルミニウム
合金薄板の連続鋳造方法および連続鋳造装置の実施の形
態を添付図面に基づいて具体的に説明する。図１に示す
ように双ドラム式連続鋳造機と同等の冷却能を有する板
状の鋳型を表１に示す種々の組成のアルミニウム合金の
溶湯中に浸漬させ急冷凝固鋳片を得た。鋳型表面粗さは
１０μm 、浸漬温度は７００℃、浸漬時間は約２秒とし
た。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method for continuously casting an aluminum alloy sheet and a continuous casting apparatus according to the present invention will be specifically described below with reference to the accompanying drawings. As shown in FIG. 1, a plate-shaped mold having a cooling capacity equivalent to that of a twin-drum type continuous casting machine was immersed in molten aluminum alloys having various compositions shown in Table 1 to obtain rapidly solidified cast pieces. The mold surface roughness was 10 μm, the immersion temperature was 700 ° C., and the immersion time was about 2 seconds.

【００１８】[0018]

【表１】 [Table 1]

【００１９】これらの鋳片、および６００℃で８時間の
熱処理を施した材料の鋳型接触側表層の晶出物粒径を表
１に示す。２．３％Ｍｎでは晶出物粒径は目標である
２．０μm に達していないが、熱処理を施すことにより
目標値に達した。Table 1 shows the grain size of the crystallized substances in the surface layer on the mold contact side of these slabs and the materials heat-treated at 600 ° C. for 8 hours. With 2.3% Mn, the crystallized grain size did not reach the target of 2.0 μm, but reached the target value by performing heat treatment.

【００２０】次に表１ＮＯ．６の組成を有する材料につ
いて図２に示す双ドラム式連続鋳造機による鋳造試験を
行った。図２において、１，１’は冷却ドラム、２，
２’はサイド堰、３はアルミニウム合金の溶湯を供給す
るノズル、４は鋳造される鋳片を示している。ディンプ
ル打設により冷却ドラム１，１’の表面粗さを４０μm
程度とし、鋳造量１００kg、鋳造温度７００℃、鋳造速
度６０m/min で鋳造し、厚さ約２．６mmの鋳片を得た。Next, Table 1 NO. The material having the composition of No. 6 was subjected to a casting test by the twin-drum type continuous casting machine shown in FIG. In FIG. 2, 1, 1'is a cooling drum, 2,
2'is a side weir, 3 is a nozzle for supplying molten aluminum alloy, and 4 is a cast piece to be cast. The surface roughness of the cooling drums 1 and 1'is 40 μm by dimple casting.
The casting amount was about 100 kg, the casting temperature was 700 ° C., and the casting speed was 60 m / min to obtain a slab having a thickness of about 2.6 mm.

【００２１】鋳造した鋳片を冷間圧延だけで０．４mm厚
の薄板とし、機械的特性を評価した。表１に示すよう
に、晶出物粒径は目標値を満足している。また表２に示
すように引張り強さ、耐力は従来のＤＣ鋳造３００４合
金板材より高い。The cast slab was made into a thin plate having a thickness of 0.4 mm only by cold rolling, and its mechanical properties were evaluated. As shown in Table 1, the crystallized substance particle size satisfies the target value. Further, as shown in Table 2, the tensile strength and proof stress are higher than those of the conventional DC cast 3004 alloy sheet material.

【００２２】[0022]

【表２】 [Table 2]

【００２３】[0023]

【発明の効果】本発明により、Ｍｎ ２．１〜４．５wt
％，Ｍｇ ０．８〜１．５wt％，Ｓｉ０．１〜０．４wt
％を含有し残部がＡｌと不可避的に含まれる不純物から
なるアルミニウム合金を用い、好ましくは表面粗さが２
０〜６０μm Ｒmax の凹凸を設けた冷却ドラムをもつ双
ドラム式連続鋳造機を用いて、最終板厚に近い厚さの、
缶用材に用いて好適なアルミニウム合金の薄板の鋳造が
可能となる。According to the present invention, Mn 2.1-4.5 wt
%, Mg 0.8 to 1.5 wt%, Si 0.1 to 0.4 wt
%, With the balance being Al and inevitably contained impurities, with an aluminum alloy having a surface roughness of preferably 2
Using a twin-drum type continuous casting machine having a cooling drum provided with irregularities of 0 to 60 μm Rmax, a thickness close to the final plate thickness,
It is possible to cast a thin plate of an aluminum alloy suitable for use as a can material.

【００２４】これにより６００mmあるＤＣ鋳造を缶用板
材とするために必要であったプロセスのうち、均一化焼
鈍、面研削、熱間圧延および冷間圧延工程の一部を省略
する事が出来る。また、双ドラム式連続鋳造機鋳片表面
はＤＣ鋳片表面に見られる肌荒れがなく、ほぼ平滑な表
面性状を有する。このため面研削を必要とせず、歩留り
が良い。このように設備の簡略化による省エネルギー化
および歩留りの向上により生産コストの大幅な低減が可
能である。As a result, it is possible to omit some of the steps of homogenizing annealing, surface grinding, hot rolling and cold rolling among the processes required for making 600 mm DC casting into a can plate material. Further, the surface of the slab of twin-drum type continuous casting machine does not have the surface roughness seen on the surface of the DC slab, and has a substantially smooth surface texture. Therefore, surface grinding is not required and the yield is good. In this way, it is possible to significantly reduce the production cost by simplifying the equipment to save energy and improve the yield.

【００２５】この板材を素材としたアルミニウム缶は従
来の３００４材に比べ約２０％高い引張り強さおよび耐
力を有するため、缶の薄肉化が可能である。更にこの板
材の強度向上に貢献している組織中の晶出物は６００℃
まで熱的に安定であるため耐熱材料としても使用でき
る。Since the aluminum can made of this plate material has a tensile strength and a proof stress which are about 20% higher than those of the conventional 3004 material, the thickness of the can can be reduced. Furthermore, the crystallized substances in the structure that contribute to the improvement of the strength of this plate are 600 ° C.
Since it is also thermally stable, it can be used as a heat resistant material.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明による鋳造方法に用いる鋳片を得るため
の鋳型浸漬試験装置の断面図。FIG. 1 is a cross-sectional view of a mold immersion test apparatus for obtaining a cast piece used in a casting method according to the present invention.

【図２】双ドラム式連続鋳造機の概念図。FIG. 2 is a conceptual diagram of a twin-drum type continuous casting machine.

【符号の説明】[Explanation of symbols]

１，１’ 冷却ドラム ２，２’ サイド堰 ３ ノズル ４ 鋳片 1,1 'Cooling drum 2, 2'Side weir 3 Nozzle 4 Slab

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【手続補正書】[Procedure amendment]

【提出日】平成８年１月１７日[Submission date] January 17, 1996

【手続補正１】[Procedure amendment 1]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】請求項５[Correction target item name] Claim 5

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【手続補正２】[Procedure amendment 2]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】００１６[Correction target item name] 0016

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【００１６】また、鋳片に熱処理を施すと固溶Ｍｎの析
出、およびオストワルド成長によって晶出物の粒径が増
大する。粒成長は熱処理温度が高い程著しく、６００℃
で８時間の熱処理を施せば２．０〜２．８μm に粒径が
増大する。しかしこれ以上高温では液相の発生および板
材のクリープ変形が生じるため熱処理温度は６００℃以
下に限定される。When heat treatment is applied to the cast slab, the grain size of the crystallized product increases due to the precipitation of solid solution Mn and the Ostwald ripening. Grain growth is more remarkable at higher heat treatment temperature, 600 ° C
When the heat treatment is performed for 8 hours , the particle size increases to 2.0 to 2.8 μm. However, if the temperature is higher than this, the liquid phase is generated and the plate material is creep-deformed, so that the heat treatment temperature is limited to 600 ° C. or lower.

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Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 Ｍｎ ２．１〜４．５wt％，Ｍｇ ０．
８〜１．５wt％，Ｓｉ ０．１〜０．４wt％を含有し残
部がＡｌ及び不可避的不純物から成るアルミニウム合金
の溶湯を、互に反対方向に回転する一対の冷却ドラムと
同ドラムの両端面に摺接するサイド堰で画成された空間
に注湯して連続的に薄板を鋳造することを特徴とするア
ルミニウム合金の薄板連続鋳造方法。1. Mn 2.1-4.5 wt%, Mg 0.
A pair of cooling drums rotating in opposite directions to each other, and a molten aluminum alloy containing 8 to 1.5 wt% and 0.1 to 0.4 wt% of Si, and the balance of Al and unavoidable impurities. A method for continuously casting a thin plate of an aluminum alloy, comprising pouring molten metal into a space defined by a side weir that is in sliding contact with a surface and continuously casting the thin plate. 【請求項２】 互に反対方向に回転する一対の冷却ドラ
ムと同ドラムの両端面に摺接する一対のサイド堰から構
成され、Ｍｎ ２．１〜４．５wt％，Ｍｇ０．８〜１．
５wt％，Ｓｉ ０．１〜０．４wt％を含有し残部がＡｌ
及び不可避的不純物から成るアルミニウム合金の薄板を
連続鋳造する装置であって、前記冷却ドラムの表面に表
面粗さ２０〜６０μm Ｒmax の凹凸を設けたことを特徴
とするアルミニウム合金の薄板連続鋳造装置。2. A pair of cooling drums rotating in mutually opposite directions and a pair of side dams slidably contacting both end faces of the drum, Mn 2.1-4.5 wt%, Mg 0.8-1.
5 wt%, Si 0.1-0.4 wt% and balance Al
And an apparatus for continuously casting a thin plate of an aluminum alloy comprising unavoidable impurities, characterized in that the cooling drum is provided with irregularities having a surface roughness of 20 to 60 μm Rmax. 【請求項３】 Ｍｎ ２．１〜４．５wt％，Ｍｇ ０．
８〜１．５wt％，Ｓｉ ０．１〜０．４wt％を含有し、
残部がＡｌ及び不可避的不純物から成るアルミニウム合
金の溶湯を、互いに反対方向に回転する一対の冷却ドラ
ムと同ドラムの両端面に摺接するサイド堰で画成された
空間に注湯して連続的に薄板を鋳造し、次いで同薄板を
冷間圧延して製造されたことを特徴とするアルミニウム
合金圧延板。3. Mn 2.1-4.5 wt%, Mg 0.
8 to 1.5 wt%, Si 0.1 to 0.4 wt%,
A molten aluminum alloy, the balance of which is Al and unavoidable impurities, is continuously poured into a space defined by a pair of cooling drums rotating in opposite directions and side dams slidably contacting both end faces of the drum. An aluminum alloy rolled plate produced by casting a thin plate and then cold rolling the thin plate. 【請求項４】 クレーム３記載の薄板を５８０〜６００
℃で熱処理した後、冷間圧延して製造されたことを特徴
とするアルミニウム合金圧延板。4. A thin plate according to claim 3 is provided with 580 to 600.
An aluminum alloy rolled plate produced by heat-treating at ℃ and cold rolling. 【請求項５】 クレーム３又は４記載のアルミニウム合
金圧延板であって、鋳造後又は熱処理後の鋳片に含まれ
るＭｎを主成分とする晶出物の平均粒径が０．２〜０．
５μm であることを特徴とするアルミニウム合金圧延
板。5. The rolled aluminum alloy plate according to claim 3 or 4, wherein the average grain size of crystallized substances mainly composed of Mn contained in the cast slab after casting or after heat treatment is 0.2 to 0.
An aluminum alloy rolled plate having a thickness of 5 μm.