JP4479114B2

JP4479114B2 - Manufacturing method of aluminum alloy thick plate for spinning process

Info

Publication number: JP4479114B2
Application number: JP2001050442A
Authority: JP
Inventors: 一光水嶋; 武森山; 靖史田島; 雄一玉置; 忍高橋
Original assignee: Nippon Light Metal Co Ltd
Current assignee: Nippon Light Metal Co Ltd
Priority date: 2001-02-26
Filing date: 2001-02-26
Publication date: 2010-06-09
Anticipated expiration: 2021-02-26
Also published as: JP2002249841A

Description

【０００１】
【発明の属する技術分野】
本発明は自動車等のホイールリムやパラボラアンテナ、鏡板、鍋釜等の円筒状、カップ状乃至椀型等の製品を得るためのスピニング加工性に優れ、加工後の表面が平滑なアルミニウム合金厚板の製造方法に関するものである。
【０００２】
【従来の技術】
円筒状、カップ状ないし椀型などのスピニング加工は図１に示すように軸を中心として回転する所定形状の成形型１に被加工材としての圧延板３を板押え４で押さえ込み、成形型１の軸方向にそって移動するロール２を移動させて被加工材たる前記圧延板３を所望形状に成形させるものである。なおこの場合の成形型１として代表的なリム形状の例は図２に示す断面図の如くである。
【０００３】
ところで上記したようなスピニング加工は図１に示したような成形型１を中心として成立し、別段大きな設備を準備しなくても加工でき、しかもアルミニウム合金は成形性が良好で圧延板から塑性加工したものは靱性が高く、成形体の厚さを薄くできて軽量化が図れるところから、上述したような製品の多くはアルミニウム合金圧延板をスピニング加工して製造されている。なおスピニング加工用の厚板は、加工材という観点から厚板全体を均一微細組織とするために、冷間圧延後再結晶させて製造されている。
【０００４】
【発明が解決しようとする課題】
スピニング加工品の肌を平滑にするために厚板の再結晶粒を微細化すると厚板の耐力が高くなりスピニング加工性が低下する。またスピニング加工性を向上させるために再結晶粒を粗大化させて板の耐力を下げると、スピニング加工品の肌が粗くなる。即ち本発明においては、上記したような従来材の欠点を解決し、スピニング加工品の表面が平滑で、かつ耐力の低い特性を合わせ持つスピニング加工性の良い厚板の製造方法を提案するものである。
【０００５】
【課題を解決するための手段】
発明者らは、スピニング加工用厚板の表層は微細な再結晶粒で、内部は粗な再結晶粒とすれば、スピニング加工品の表面が平滑でかつスピニング加工性の良好な厚板が得られるものとして本発明を完成したものである。
【０００７】
即ち、本発明は、Ｍｇが２．０〜３．４重量％、Ｃｕが０．０５〜０．１０重量％、ＳｉとＦｅの合計量が０．０５〜０．０９重量％、鋳造組織微細化剤が０．００５〜０．２重量％、残部Ａｌおよび不可避的不純物とし、該不可避的不純物のうち、Ｍｎ、ＣｒおよびＺｒをそれぞれ０.０１重量％以下に規制したアルミニウム合金鋳塊を均質化処理し、次いで該鋳塊を複数パスで熱間圧延するにあたって、熱間圧延の最終パスの圧下率を４３％以上、ワークロール出側板厚さを５〜１０ｍｍとし、該熱間圧延板を板の自熱で再結晶させることを特徴とするスピニング加工用アルミニウム合金厚板の製造方法である。Ｓｉ、Ｆｅ等の再結晶核を形成する元素が少ないから、このような製造方法とすることによって、熱間圧延後の板の自熱で、厚板の表層部は再結晶粒サイズが平均値で５０μm 以下、中心部の再結晶粒サイズが平均値で７０μm 以上の厚板を容易に得ることができる。ここで熱間圧延の最終パスの圧下率の上限は５５％程度である。これ以上となると板中心部の再結晶粒サイズが小さくなる。また、自熱で再結晶した熱間圧延後の合金厚板を再度再結晶温度に加熱すると、板のコイルの巻き始め等の再結晶不完全部分を再結晶化できて板全体の機械的特性を均一化できる。
【０００８】
なお上述したスピニング加工は上記した如く、厚板と型が共に回転している状態で、ロール治具を使用して厚板を型面形状にならしていく加工方法であるために、厚板表層部の結晶粒は延ばされた状態で加工品の外観となる。厚板表層部の結晶粒サイズが小さければ延ばされても小さく、平滑感は損なわれない。平滑感を損なわない加工前の厚板表層部の結晶粒サイズは円相当径平均値で約５０μm 以下である。さらに小サイズであれば良好となる。しかしながら厚板全体が小結晶粒サイズとなると、ホールペッチの法則で知られているように耐力が高くなり、スピニング加工の速度が低下し生産性を下げる。従って本発明の如く、厚板表層部は小再結晶粒サイズ、中心部は粗な再結晶粒サイズとする。
【０００９】
上述したようなスピニング加工で加工品の表面性状に影響を与えるのは概略0.５mm程度であるから、表層部の厚さは0.５mmの範囲で小結晶粒サイズであればよい。一方中心部は逆に粗な再結晶粒サイズとし、その部分の耐力を低下させ全体として加工性を良好なものとさせる。中心部の結晶粒サイズが円相当径平均値で約７０μm 以上であると全体的な耐力も低下し、スピニング加工性が良くなる。結晶粒サイズは、表層部から中心部へ徐々に大きくなっていく。中心部の厚さは２mmの範囲で粗な結晶粒サイズであればよい。なおここで結晶粒サイズが円相当径平均値とは、単位視野内における再結晶数から計算される平均１再結晶粒当りの円相当径をいう。
【００１０】
【発明の実施の形態】
上述したような本発明によるスピニング加工用アルミニウム合金厚板の製造方法は、以下に述べる組成を有するアルミニウム合金鋳塊を用いる。Ｍｇ：２．０〜３．４重量％、およびＣｕ：０．０５〜０．１０重量％とする。ＭｇおよびＣｕは非熱処理タイプの加工品に強度を付与するためのもので、下限値未満では実製品としての強度不足となり、また上限値を超えると加工硬化が大きくスピニング加工速度が低下する。またこれらの元素は固溶タイプの元素でこの程度の含有量であれば他の元素含有量の規制と相まって金属間化合物を形成し難く、再結晶の核と成り難い。
【００１１】
SiとFeの合計量を0.０５〜0.０９重量％とする。
SiとFeはAl−Fe系化合物およびAl−Si−Fe系化合物の１種または２種を形成させ、再結晶の核となるものである。下限値未満では再結晶の核の数が少なく、厚板表層部の再結晶粒の微細化が困難になる。上限値を超えると厚板中心部の再結晶粒も微細化してしまう。SiとFeは添加してもいいし、返り材の調整で含有させることもできる。
【００１２】
鋳造組織微細化剤を0.００５〜0.２重量％使用する。
鋳造組織微細化剤は鋳造割れ防止のために添加するものである。下限値未満では効果が少なく、上限値を超えても効果が飽和し経済的でない。鋳造組織微細化剤としては、例えばTi単独、TiとＢの併用等がある。Ti単独の場合は、Ti：0.００５〜0.２重量％、TiとＢの併用の場合は、Ti：0.００５〜0.２重量％およびＢ：0.００５〜0.２重量％をアルミニウム合金溶湯に含有させればよい。
【００１３】
Mn、CrおよびZrをそれぞれ0.０１重量％以下とする。
アルミニウムには製錬および返り材から入って来る元素が多数あるが、そのなかでも含有量が多くかつそれらの化合物が再結晶粒の核となり易い元素は原料を選別し、品位の高い地金および返り材を使用する。即ちMn、CrおよびZrのそれぞれの元素が上限値を超えると、金属間化合物を形成して厚板の中心部も微細再結晶粒となり好ましくない。他の不可避的不純物は各0.０５重量％以下であることが好ましい。
【００１４】
上記組成のアルミニウム合金鋳塊を均質化処理する。均質化処理は特に限定するものではないが、例えば鋳塊の加熱昇温速度を１５０℃／時間以下、加熱温度範囲を４４０〜５４０℃、保持時間を１〜２４時間とし、あるいは鋳塊の上記加熱温度範囲を含有合金元素の固溶条件に適した温度、例えば４４０〜４９０℃の低温部と、４９０〜５４０℃の高温部の２段に分け、それぞれの温度領域に加熱保持してもよい。
【００１５】
上述したような条件で均質化処理した上記鋳塊を、複数パスで熱間圧延する。熱間圧延するにあたって熱間圧延の最終パスの圧下率を４３％以上、ロール出側板厚さを５〜１０mmとし、該熱間圧延板をコイルにし自熱で再結晶させる。熱間圧延の最終パスの圧下率を４３％以上とするのは、厚板表層部に大きな加工歪を付与し、厚板中心部はその歪が減衰し軽度の加工歪となることにより、このようにして加工された厚板を圧延ロール出側の厚板自体の熱で再結晶化し、あるいは再度再加熱して再結晶化させる。このようにすることにより、厚板表層部の再結晶粒は微細化し、Si、Fe、Mn、CrおよびZrのように再結晶の核となる化合物を形成する元素が少ないことと中心部の軽度の加工歪とが相まって、厚板中心部の再結晶粒は粗大化する。ロール出側板厚さを５〜１０mmとするのは板の厚さが薄ければ中心部まで大きな加工歪が伝搬し、厚板の表層部と同様に再結晶粒が微細化してしまうからである。板厚さの上限値は実際のスピニング加工用板としての値である。熱延上がりの厚板温度は３２０℃以上であれば等軸晶の再結晶を得ることができる。上限は３８０℃程度でこの温度を超えると再結晶粒の成長が発生し易い。
【００１６】
【実施例】
上記したような本発明によるものの具体的な実施例について説明すると以下の如くである。
【実施例１】
本発明者等が具体的に採用した合金の組成は次の表１に示す如くである。
【００１７】
【表１】

【００１８】
前記した表１の合金符号１−Ａおよび１−Ｂに示す組成のアルミニウム合金を溶製し、半連続鋳造して厚さ約５００mmのスラブ鋳塊を鋳造した。該鋳塊の表面を厚さ１５mm面削除去後昇温速度１２０℃／時間で加熱し、５００±１０℃に１２時間保持して均質化処理をした。熱間圧延は７パスとし、６パス後の板厚を9.４mm、１4.５mmおよび１7.５mmの３種とし、７パス目の最終熱間圧延で８mmに圧延しコイル巻きした。それぞれの圧下率は１５％、４５％、５４％、ロール出側板温度で３４０℃であった。
【００１９】
自熱による再結晶終了後、室温で機械的性質および厚板の表面より0.５mm下、および中央の結晶粒のサイズを測定した。測定面は圧延方向で板厚方向の断面である。測定方法は画像解析装置を用いて測定視野0.２８mm²内の再結晶粒数から計算した円相当径平均値である。この測定結果は次の表２に示す如くであった。
【００２０】
【表２】

【００２１】
なお次の表３には上記したような実施例における圧下率４５％板の熱間圧延後自熱で再結晶させたものの機械的性質を示した。
【００２２】
【表３】

【００２３】
前記した表２の結果から、圧下率１５％では表層部と中心部では再結晶粒のサイズに顕著な差は見られず、しかも表層部の再結晶サイズが大きい。４５％、５４％では顕著な差が見られ、表層部の再結晶サイズが小さい。
【００２４】
比較例として、上述と同様にして得られた厚さ１2.３mmの熱間圧延板を冷間圧延で厚さ８mmの冷間圧延板とした。次いで３４０℃の温度に加熱し、１時間保持して再結晶させた。機械的特性および再結晶粒の円相当径を測定した。測定条件は実施例と同じであるが、このような結果は次の表４に示す如くである。
【００２５】
【表４】

【００２６】
前記したような表４の結果によるならば、圧下率３５％で冷間圧延し再結晶させた厚板は、表層部と中心部では再結晶粒のサイズに大きな差は見られず、しかも表層部の再結晶サイズが大きい。
【００２７】
【実施例２】
実施例１の本発明例における４５％熱間圧延後の再結晶板と比較例の２５％冷間圧延後の再結晶板を用いて、下記する条件でスピニング加工性を比較した。即ち前述した図１に示す如き装置を用い、上記の板成形型に板押さえで押さえ加工した。
成形型寸法：２５０mmφ
板寸法：８mm×３５０mmφ
成形型回転数：３００rpm
ロール送り測度：６００mm／分
ロールと成形型の間隔：７mm
潤滑油なし
【００２８】
加工終了後板の表面を目視観察し、割れ発生の有無および肌荒れの有無を目視で判断した結果を次の表５に示す。
【００２９】
【表５】

【００３０】
即ち上述したような本発明のスピニング加工用厚板は、肌が平滑でかつスピニング加工性が良好であるから、優れた加工品を生産性良く生産できる効果を有しており、また本発明のスピニング加工用厚板の製造方法は、熱間圧延後の自熱で再結晶させているので、省エネ効果を有していることも明らかである。
【００３１】
【発明の効果】
以上説明したような本発明によるならば、車輌用ホイールリムやパラボラアンテナ、鏡板、鍋釜などの円筒状ないしカップ状、椀型などの各種製品を得るためのスピニング加工性に優れ、加工後の表面性状の卓越した平滑なアルミニウム合金厚板および該合金厚板の好ましい製造を得しめることが明らかであり、工業的にその効果の大きい発明であることが明らかである。
【図面の簡単な説明】
【図１】スピニング加工の状態を示した断面的説明図である。
【図２】図１に示したものにおける成形型としてホイール成形型の１例についての断面図である。
【図３】本発明における再結晶粒測定位置についての説明図である。
【符号の説明】
１軸を中心として回転する成形型
２成形型を横方向に移動させるロール
３被加工材たる板
４板押え
５再結晶粒サイズ測定位置
６中心部
７板厚方向[0001]
BACKGROUND OF THE INVENTION
The present invention is an aluminum alloy thick plate which is excellent in spinning workability for obtaining a product such as a wheel rim, a parabolic antenna, a mirror plate, a pan, etc., such as a car, a cup shape or a bowl shape, and has a smooth surface after processing. It is related with the manufacturing method .
[0002]
[Prior art]
As shown in FIG. 1, a spinning process such as a cylindrical shape, a cup shape, or a bowl shape is performed by pressing a rolling plate 3 as a workpiece with a plate presser 4 into a mold 1 having a predetermined shape that rotates about an axis. The rolled plate 3 which is a work material is formed into a desired shape by moving the roll 2 which moves along the axial direction. An example of a typical rim shape as the mold 1 in this case is as shown in a cross-sectional view of FIG.
[0003]
By the way, the spinning process as described above is mainly performed with the forming die 1 as shown in FIG. 1 and can be processed without preparing a particularly large facility, and the aluminum alloy has good formability and plastic processing from a rolled plate. Since these products have high toughness and the thickness of the compact can be reduced to reduce the weight, many of the products as described above are manufactured by spinning aluminum alloy rolled plates. In addition, the thick plate for spinning is manufactured by recrystallization after cold rolling in order to make the entire thick plate into a uniform fine structure from the viewpoint of a processed material.
[0004]
[Problems to be solved by the invention]
If the recrystallized grains of the thick plate are refined in order to smooth the skin of the spinning processed product, the proof stress of the thick plate is increased and the spinning workability is lowered. Further, if the recrystallized grains are coarsened to reduce the yield strength of the plate in order to improve the spinning processability, the skin of the spinning processed product becomes rough. That is, the present invention proposes a method for producing a thick plate with good spinning workability, which solves the above-mentioned drawbacks of conventional materials and has a smooth surface of a spinning processed product and a low proof stress. is there.
[0005]
[Means for Solving the Problems]
The inventors obtained a thick plate with a smooth surface and a good spinning workability if the surface layer of the spinning plate is a fine recrystallized grain and the inside is a coarse recrystallized grain. As a result, the present invention has been completed.
[0007]
That is, according to the present invention, Mg is 2.0 to 3.4% by weight, Cu is 0.05 to 0.10% by weight, and the total amount of Si and Fe is 0.05 to 0.09% by weight. An aluminum alloy ingot in which 0.005 to 0.2% by weight of the agent, the balance Al and unavoidable impurities are included, and Mn, Cr and Zr are regulated to 0.01% by weight or less among the unavoidable impurities is homogeneous. Then, when hot rolling the ingot in a plurality of passes, the rolling reduction of the final pass of hot rolling is 43% or more, the work roll outlet side plate thickness is 5 to 10 mm, A method for producing an aluminum alloy thick plate for spinning, which is characterized by recrystallization by self-heating of the plate. Since there are few elements that form recrystallization nuclei such as Si and Fe , the surface layer portion of the thick plate has an average recrystallized grain size due to the self-heating of the plate after hot rolling by using such a production method. Thus, a thick plate having an average recrystallized grain size of 70 μm or more at the center can be easily obtained. Here, the upper limit of the rolling reduction of the final pass of hot rolling is about 55%. If it exceeds this, the recrystallized grain size in the center of the plate will be reduced. In addition, when the thick alloy plate after hot rolling recrystallized by self-heating is heated again to the recrystallization temperature, imperfect recrystallization parts such as the start of coiling of the plate can be recrystallized, and the mechanical properties of the entire plate Can be made uniform.
[0008]
The spinning process described above is a processing method in which the thick plate and the mold are rotated together and the thick plate is shaped into a mold surface shape using a roll jig. The crystal grains in the surface layer portion become the appearance of the processed product in an extended state. If the crystal grain size of the thick plate surface layer portion is small, it is small even if it is extended, and the smoothness is not impaired. The crystal grain size of the thick plate surface layer portion before processing that does not impair the smoothness is about 50 μm or less in terms of the equivalent circle diameter average value. Smaller sizes are better. However, when the whole thick plate has a small crystal grain size, the yield strength increases as is known by the Hall Petch's law, and the spinning speed decreases and productivity decreases. Therefore, as in the present invention, the thick plate surface layer portion has a small recrystallized grain size and the central portion has a coarse recrystallized grain size.
[0009]
In the spinning process as described above, the surface property of the processed product is affected by about 0.5 mm. Therefore, the thickness of the surface layer portion may be a small crystal grain size within the range of 0.5 mm. On the other hand, the central portion has a coarse recrystallized grain size, and the yield strength of the portion is lowered to improve the workability as a whole. When the crystal grain size at the center is about 70 μm or more in terms of the equivalent circle diameter average value, the overall yield strength is lowered and the spinning workability is improved. The crystal grain size gradually increases from the surface layer to the center. The thickness of the central portion may be a coarse crystal grain size in the range of 2 mm. Here, the average value of the equivalent circle diameter of the crystal grains means the equivalent circle diameter per average recrystallized grain calculated from the number of recrystallizations in the unit visual field.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The above-described method for producing a spinning aluminum alloy thick plate according to the present invention uses an aluminum alloy ingot having the following composition. Mg: 2.0 to 3.4 wt% and Cu: 0.05 to 0.10 wt%. Mg and Cu are for imparting strength to a non-heat treated type processed product, and if it is less than the lower limit value, the strength as an actual product is insufficient, and if it exceeds the upper limit value, work hardening is large and spinning processing speed is reduced. In addition, these elements are solid solution type elements, and if they are contained at this level, it is difficult to form an intermetallic compound in combination with restrictions on the contents of other elements, and it is difficult to become a nucleus of recrystallization.
[0011]
The total amount of Si and Fe is 0.05 to 0.09% by weight.
Si and Fe form one or two of an Al—Fe-based compound and an Al—Si—Fe-based compound and serve as a nucleus for recrystallization. If it is less than the lower limit, the number of recrystallized nuclei is small and it becomes difficult to refine the recrystallized grains in the surface layer portion of the thick plate. If the upper limit is exceeded, the recrystallized grains at the center of the thick plate will also be refined. Si and Fe may be added, or may be contained by adjusting the return material.
[0012]
0.005 to 0.2% by weight of cast structure refiner is used.
The cast structure refining agent is added to prevent casting cracks. Less than the lower limit is less effective, and exceeding the upper limit is not economical because the effect is saturated. Examples of the cast structure refining agent include Ti alone and combined use of Ti and B. In the case of Ti alone, Ti: 0.005 to 0.2% by weight; in the case of combined use of Ti and B, Ti: 0.005 to 0.2% by weight and B: 0.005 to 0.2% by weight May be contained in the molten aluminum alloy.
[0013]
Mn, Cr and Zr are each 0.01% by weight or less.
Aluminum contains many elements that come from smelting and reclaiming materials. Among them, the elements that are high in content and whose compounds are likely to become the core of recrystallized grains are selected as raw materials. Use return material. That is, when each element of Mn, Cr, and Zr exceeds the upper limit, an intermetallic compound is formed, and the central portion of the thick plate also becomes fine recrystallized grains, which is not preferable. The other inevitable impurities are preferably 0.05% by weight or less.
[0014]
The aluminum alloy ingot having the above composition is homogenized. The homogenization treatment is not particularly limited. For example, the heating rate of the ingot is 150 ° C./hour or less, the heating temperature range is 440 to 540 ° C., the holding time is 1 to 24 hours, or the above ingot The heating temperature range may be divided into two stages, a temperature suitable for the solid solution conditions of the contained alloy element, for example, a low temperature part of 440 to 490 ° C. and a high temperature part of 490 to 540 ° C., and may be heated and held in each temperature region. .
[0015]
The ingot that has been homogenized under the conditions described above is hot-rolled in multiple passes. In the hot rolling, the rolling reduction in the final pass of the hot rolling is 43% or more, the roll outlet side plate thickness is 5 to 10 mm, and the hot rolled plate is used as a coil to be recrystallized by self-heating. The reduction ratio of the final pass of the hot rolling is set to 43% or more because a large processing strain is given to the surface portion of the thick plate, and the strain is attenuated at the central portion of the thick plate to become a mild processing strain. The thick plate thus processed is recrystallized by the heat of the thick plate itself on the exit side of the rolling roll, or reheated again to be recrystallized. By doing so, the recrystallized grains on the surface layer of the thick plate are refined, and there are few elements that form compounds that become the core of recrystallization such as Si, Fe, Mn, Cr, and Zr, and the mildness of the central part Combined with this processing strain, the recrystallized grains at the center of the thick plate become coarse. The roll exit side plate thickness is set to 5 to 10 mm because if the plate thickness is thin, a large processing strain propagates to the center, and the recrystallized grains become finer like the surface layer portion of the plate. . The upper limit value of the plate thickness is a value as an actual spinning plate. If the thick plate temperature after hot rolling is 320 ° C. or more, equiaxed recrystallization can be obtained. The upper limit is about 380 ° C., and if this temperature is exceeded, the growth of recrystallized grains tends to occur.
[0016]
【Example】
A specific embodiment of the present invention as described above will be described as follows.
[Example 1]
The composition of the alloy specifically adopted by the present inventors is as shown in Table 1 below.
[0017]
[Table 1]

[0018]
Aluminum alloys having the compositions shown in the alloy codes 1-A and 1-B in Table 1 were melted and semi-continuously cast to cast a slab ingot having a thickness of about 500 mm. The surface of the ingot was removed at a thickness of 15 mm and heated at a heating rate of 120 ° C./hour and held at 500 ± 10 ° C. for 12 hours for homogenization. The hot rolling was 7 passes, the thickness after 6 passes was 9.4 mm, 14.5 mm, and 17.5 mm, the final hot rolling in the 7th pass was rolled to 8 mm and coiled. The respective rolling reductions were 15%, 45% and 54%, and the roll exit side plate temperature was 340 ° C.
[0019]
After completion of recrystallization by self-heating, the mechanical properties and the size of the crystal grains 0.5 mm below and in the center of the surface of the plank were measured at room temperature. The measurement surface is a cross section in the thickness direction in the rolling direction. The measuring method is an average value of equivalent circle diameters calculated from the number of recrystallized grains in a measurement visual field of 0.28 mm ² using an image analyzer. The measurement results were as shown in Table 2 below.
[0020]
[Table 2]

[0021]
Table 3 below shows the mechanical properties of the 45% rolling reduction plate in the above-described example and recrystallized by self-heating after hot rolling.
[0022]
[Table 3]

[0023]
From the results shown in Table 2 above, when the rolling reduction is 15%, there is no significant difference in the size of recrystallized grains between the surface layer portion and the center portion, and the recrystallization size of the surface layer portion is large. A significant difference is seen at 45% and 54%, and the recrystallized size of the surface layer is small.
[0024]
As a comparative example, a hot rolled plate having a thickness of 12.3 mm obtained in the same manner as described above was cold-rolled to obtain a cold rolled plate having a thickness of 8 mm. Subsequently, it was heated to a temperature of 340 ° C. and held for 1 hour for recrystallization. The mechanical properties and the equivalent circle diameter of the recrystallized grains were measured. The measurement conditions are the same as in the examples, but such results are as shown in Table 4 below.
[0025]
[Table 4]

[0026]
According to the results of Table 4 as described above, in the thick plate cold-rolled and recrystallized at a reduction rate of 35%, there is no significant difference in the size of the recrystallized grains between the surface layer and the center, and the surface layer The recrystallization size of the part is large.
[0027]
[Example 2]
Using the recrystallized plate after 45% hot rolling in the inventive example of Example 1 and the recrystallized plate after 25% cold rolling of the comparative example, spinning workability was compared under the following conditions. That is, using the apparatus as shown in FIG. 1 described above, the above plate forming die was pressed with a plate press.
Mold size: 250mmφ
Plate size: 8mm × 350mmφ
Mold rotation speed: 300rpm
Roll feed measurement: 600 mm / min. Distance between roll and mold: 7 mm
Without lubricant [0028]
Table 5 below shows the results of visually observing the surface of the plate after completion of processing and visually determining whether cracks occurred and whether the skin was rough.
[0029]
[Table 5]

[0030]
That is, the spinning plate of the present invention as described above has an effect of producing an excellent processed product with high productivity since the skin is smooth and the spinning processability is good. It is also clear that the method for producing a spinning plate has an energy saving effect because it is recrystallized by self-heating after hot rolling.
[0031]
【The invention's effect】
According to the present invention as described above, it is excellent in spinning workability to obtain various products such as cylindrical or cup-shaped, bowl-shaped products such as vehicle wheel rims, parabolic antennas, end plates, pots, etc. It is clear that an excellent smooth aluminum alloy slab with excellent surface properties and a preferred production of the alloy slab can be obtained, and it is clear that this is an industrially significant invention.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing a state of spinning processing.
FIG. 2 is a cross-sectional view of an example of a wheel mold as a mold in the one shown in FIG.
FIG. 3 is an explanatory diagram of recrystallized grain measurement positions in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mold which rotates centering on the axis 2 Roll which moves a mold laterally 3 Plate which is a work material 4 Plate clamp 5 Recrystallized grain size measurement position 6 Center part 7 Plate thickness direction

Claims

Mg is 2.0 to 3.4% by weight, Cu is 0.05 to 0.10% by weight, the total amount of Si and Fe is 0.05 to 0.09% by weight, and the cast structure refiner is 0.005. An aluminum alloy ingot in which Mn, Cr and Zr are regulated to 0.01% by weight or less of the inevitable impurities, respectively, is homogenized, and the remaining Al and inevitable impurities are -0.2% by weight. When the ingot is hot-rolled in multiple passes, the rolling reduction of the final pass of hot rolling is 43% or more, the work roll outlet side plate thickness is 5 to 10 mm, and the hot-rolled plate is reheated by the plate's self-heating. A method for producing an aluminum alloy thick plate for spinning, which comprises crystallizing.

2. The method for producing an aluminum alloy thick plate for spinning according to claim 1, wherein the hot rolled sheet recrystallized by self-heating of the sheet is recrystallized again.