JPH05320808A

JPH05320808A - Aluminum alloy sheet for di forming

Info

Publication number: JPH05320808A
Application number: JP15577592A
Authority: JP
Inventors: Katsumi Koyama; 克己小山; Seiichiro Fujikawa; 聖一郎藤川
Original assignee: Furukawa Aluminum Co Ltd
Current assignee: Furukawa Aluminum Co Ltd
Priority date: 1992-05-22
Filing date: 1992-05-22
Publication date: 1993-12-07
Anticipated expiration: 2014-12-27
Also published as: JP2994140B2

Abstract

PURPOSE:To improve the strength and workability of an aluminum allay sheet for DI forming by specifying its chemical compsn. and the content of hydrogen. CONSTITUTION:The chemical compsn. of an aluminum alloy sheet for DI forming is constituted of a one contg., by weight, 0.8 to 1.5% Mn and 0.7 to 1.3 % Mg and furthermore contg. one or >= two kinds among 0.05 to 0.3% Cu, 0.1 to 0.3% Si, 0.1 to 0.7% Fe and 0.1 to 0.25% Zn, and the balance Al with inevitable impurities, and the content of hydrogen is regulated to <0.12ml/100g. In this way, the objective aluminum allay sheet excellent in mechanical strength and DI workability and used for a DI can such as a beer can be obtd.

Description

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

【０００１】[0001]

【産業上の利用分野】本発明は成形用アルミニウム合金
板に関するものであり、特にＤＩ缶等しごき加工を施し
て成形する用途に用いるＤＩ成形用アルミニウム合金板
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming aluminum alloy sheet, and more particularly to a DI forming aluminum alloy sheet for use in forming by performing ironing on a DI can.

【０００２】[0002]

【従来の技術とその課題】アルミニウム製ビール缶ある
いは一般飲料缶の胴材としてこれまでＡＡ３００４合金
（Ａｌ−１．２５wt％Ｍｎ−１．０５wt％Ｍｇ合金）が
使用されている。本合金は本来高い加工度の冷間圧延に
よりある程度成形性に優れかつ胴材として必要な強度を
有しているために使用されているものである。しかしな
がら近年さらなるコストダウンを目的として材料の薄肉
化が求められており、これに対応して飲食缶の胴材に要
求される強度は従来よりも高くなって来ている。この強
度向上のために開発されたものとしては、特開昭５２−
１０５５０９号公報のようにＭｇ₂Ｓｉの析出を利用し
たもの、あるいは特開昭５７−１２０６４８号公報のよ
うにＡｌ−Ｃｕ−Ｍｇ系の析出物による析出硬化を利用
したアルミニウム合金板の製造方法が知られている。ま
た一方コストダウンの方法として成形工程での不具合を
低減することによる生産性の向上も大きな課題となって
いる。特に薄肉化かつ高強度化が進むことによりしごき
加工時の割れの発生が問題となる。このため析出物と冷
延との相互作用について検討した特公昭６３−６５７４
５号公報が知られている。従来までの検討では強度の向
上と成形性の向上とが相反する結果をもたらし、高強度
が得られる材料は一般的に成形性が劣る結果となってい
た。ところで金属材料中の水素原子は従来、熱処理時に
膨れを生じ表面欠陥となるためにこれを規制していた。
この水素含有量を低減する方法として鋳造前に不活性ガ
スを溶湯中に吹き込む脱ガス処理を行っており、通常
０．３ml／１００ｇ以下程度の水素含有量において上記
問題を回避している。2. Description of the Related Art AA3004 alloy (Al-1.25 wt% Mn-1.05 wt% Mg alloy) has hitherto been used as a body material for aluminum beer cans or general beverage cans. This alloy is originally used because it is excellent in formability to some extent by cold rolling with a high workability and has the strength required as a body material. However, in recent years, there has been a demand for thinner materials for the purpose of further cost reduction, and in response to this, the strength required for the body material of food and drink cans has become higher than before. As one developed to improve the strength, Japanese Patent Laid-Open No. 52-
No. 105509, which utilizes precipitation of Mg ₂ Si, or Japanese Patent Application Laid-Open No. 57-120648, which uses a precipitation hardening method using an Al—Cu—Mg-based precipitate, there is a method for producing an aluminum alloy sheet. Are known. On the other hand, improvement of productivity by reducing defects in the molding process as a method of cost reduction is also a major issue. In particular, cracking during ironing becomes a problem due to the progress of thinner and higher strength. Therefore, the interaction between precipitates and cold rolling was examined.
No. 5 publication is known. In the studies conducted up to now, the improvement in strength and the improvement in moldability are in conflict with each other, and a material capable of obtaining high strength is generally inferior in moldability. By the way, hydrogen atoms in metal materials have conventionally been regulated because they swell during heat treatment and become surface defects.
As a method for reducing the hydrogen content, degassing treatment in which an inert gas is blown into the molten metal is performed before casting, and the above problem is usually avoided at a hydrogen content of about 0.3 ml / 100 g or less.

【０００３】[0003]

【発明が解決しようとする課題】本発明は上記のような
強度および成形性にともに影響する要因以外にＤＩ成形
性に影響を与える要因を探すことによりなされたもの
で、強度に変化をもたらすことなくＤＩ成形性、特にし
ごき加工性を改善したＤＩ成形用アルミニウム合金板を
提供するものである。SUMMARY OF THE INVENTION The present invention has been made by searching for factors affecting DI moldability in addition to the factors affecting both strength and moldability as described above. It is intended to provide an aluminum alloy plate for DI molding which has improved DI moldability, particularly ironing workability.

【０００４】[0004]

【課題を解決するための手段】即ち本発明は、Ｍｎ０．
８〜１．５wt％、Ｍｇ０．７〜１．３wt％を含み、さら
にＣｕ０．０５〜０．３wt％、Ｓｉ０．１〜０．３wt
％、Ｆｅ０．１〜０．７wt％、Ｚｎ０．１〜０．２５wt
％のうちの１種または２種以上を含み、残部がＡｌと不
可避的不純物とからなり、かつ水素含有量が０．１２ml
／１００ｇ未満であることを特徴とするＤＩ成形用アル
ミニウム合金板である。That is, according to the present invention, Mn0.
8 ~ 1.5wt%, Mg0.7 ~ 1.3wt%, Cu0.05 ~ 0.3wt%, Si0.1 ~ 0.3wt%
%, Fe 0.1 to 0.7 wt%, Zn 0.1 to 0.25 wt
% Of 1% or more, the balance is Al and inevitable impurities, and the hydrogen content is 0.12 ml.
The aluminum alloy plate for DI molding is characterized in that it is less than 100 g.

【０００５】[0005]

【作用】本発明においてＭｎはＦｅおよびＳｉとともに
金属間化合物を形成し、しごき加工時のダイスへの焼き
付きを防止するためにＤＩ成形用材料には不可欠な元素
である。０．８wt％（以下単に％と略記）未満ではこの
効果が少なく、長時間におよぶ成形には不向きとなる。
また１．５％を超えると通常の鋳造条件では巨大な化合
物を形成し易くなり、成形時の亀裂発生の起点となる大
きな第２相となる可能性が高い。ＭｇはＣｕと同様、主
に固溶することにより本発明合金の強度を向上させる重
要な元素である。また溶体化処理および焼き入れにより
過飽和の固溶状態とすることにより缶成形後の塗装焼き
付けにおける２００℃前後の熱処理時にＭｇ₂Ｓｉある
いはＡｌ−Ｍｇ−Ｃｕ系析出物を形成し、さらに強度向
上を図ることができる。Ｍｇ添加量が０．７％未満では
必要な強度を維持できず、１．３％を超えると焼き付き
が発生し易くなる。凝固速度の速い特別な鋳造方法を用
いることにより、耐焼き付き性の高いＭｎ系の析出物の
密度を上げることで、さらにＭｇ添加量を２．５％まで
増すことは可能である。ＦｅもＭｇと同様に強度向上の
効果があるが０．１％未満ではその効果が少なく、０．
７％を超える添加ではＭｎ元素と同様、巨大化合物の形
成をもたらす。ここで鋳造時の冷却速度が著しく速い連
続鋳造法等を行う場合には上記化合物の大きさを小さく
抑えることが可能になるためＭｎ、Ｆｅの添加量をさら
に２倍まで多くすることができる。ＣｕはＭｇと同様の
効果が期待できる。したがって０．０５％未満では強度
の向上効果が期待できず、０．３％を超えると成形性を
害するとともに耐食性の点においても問題を生じる。Ｓ
ｉはそれ自体の固溶硬化性は低いが、熱処理の初期段階
において形成される微細化合物が他の元素の析出物の核
生成場所となることによって、他の元素の析出を促進す
る。そのためＳｉ添加はＦｅ、Ｍｎの固溶量を下げると
ともに析出硬化をもたらすＡｌ−Ｍｇ−Ｃｕ系化合物の
析出を促進する。またさらに多いＳｉの添加によりさら
に微細なＡｌ−Ｃｕ−Ｍｇ−Ｓｉ系化合物（Ａｌ₅Ｃｕ
₂Ｍｇ₈Ｓｉ₆のＱ相の準安定相）を新たに生じる。強
度向上を図るためには事実上０．１％以上を必要とす
る。しかしこれら析出物は強度の向上に有効であるが後
者の化合物は前者と比較してより微細であり、成形性を
著しく低下させる。そのためＳｉ添加量は０．３０％以
下とする必要がある。Ｚｎは主に固溶状態においてその
強度を増加させる。したがってその添加量が０．１％未
満ではその作用が期待されず、また０．２５％を超える
と耐食性を害するようになる。In the present invention, Mn forms an intermetallic compound together with Fe and Si and is an essential element in the DI molding material in order to prevent seizure on the die during ironing. If it is less than 0.8 wt% (hereinafter simply abbreviated as%), this effect is small and it is not suitable for molding for a long time.
On the other hand, if it exceeds 1.5%, a huge compound is likely to be formed under normal casting conditions, and there is a high possibility that a large second phase will be a starting point of crack generation during molding. Similar to Cu, Mg is an important element that improves the strength of the alloy of the present invention by mainly forming a solid solution. In addition, by making it a supersaturated solid solution state by solution treatment and quenching, Mg ₂ Si or Al-Mg-Cu based precipitates are formed during heat treatment at around 200 ° C in coating baking after can forming, further improving strength. Can be planned. If the amount of Mg added is less than 0.7%, the required strength cannot be maintained, and if it exceeds 1.3%, seizure tends to occur. By using a special casting method with a fast solidification rate, it is possible to increase the density of Mn-based precipitates having high seizure resistance and further increase the Mg addition amount to 2.5%. Fe, like Mg, has the effect of improving the strength, but if it is less than 0.1%, the effect is small, and
Addition of more than 7% leads to the formation of giant compounds, similar to Mn element. Here, when performing a continuous casting method or the like in which the cooling rate during casting is remarkably high, the size of the above compound can be suppressed to a small value, so that the addition amounts of Mn and Fe can be further doubled. Cu can be expected to have the same effect as Mg. Therefore, if it is less than 0.05%, the effect of improving the strength cannot be expected, and if it exceeds 0.3%, the formability is impaired and a problem occurs in terms of corrosion resistance. S
Although i has a low solid solution hardening property by itself, the fine compound formed in the initial stage of the heat treatment serves as a nucleation site for precipitates of other elements, thereby promoting precipitation of other elements. Therefore, the addition of Si reduces the solid solution amount of Fe and Mn and promotes the precipitation of Al-Mg-Cu-based compound that causes precipitation hardening. Furthermore many Si finer Al-Cu-Mg-Si-based compound by the addition of (Al ₅ Cu
_{2 A} new metastable phase of the Mg phase of Mg ₈ Si ₆ ) is newly generated. Virtually 0.1% or more is required to improve the strength. However, although these precipitates are effective in improving the strength, the latter compound is finer than the former compound and remarkably deteriorates the formability. Therefore, the amount of Si added needs to be 0.30% or less. Zn mainly increases its strength in the solid solution state. Therefore, if the added amount is less than 0.1%, the effect is not expected, and if it exceeds 0.25%, the corrosion resistance is impaired.

【０００６】アルミニウム合金中の水素原子は母相の原
子配列の乱れた部分に偏析する。母相の原子配列が乱れ
た場所として粒界、晶出物や析出物の界面あるいはせん
断帯などが上げられる。偏析した水素原子はその界面の
強度を低下させる。そのため成形限界に近い状態になっ
た場合に弱くなったこれら界面を起点として亀裂が生じ
ることとなることが判った。逆にこれら界面の強度を維
持することにより、析出処理などにより本発明合金の積
極的な強度向上を図った場合の成形性低下を回避でき
る。亀裂発生点の強度を維持するためには水素含有量と
して１００ｇのアルミニウム合金中に０．１２ml未満、
さらに望ましくは０．１ml未満の水素量であることが要
求される。特に多段成形が施されるＤＩ成形缶の最終し
ごき加工においてその影響が明白となる。このような低
濃度の水素含有量を得るためには鋳造直前に順次不活性
ガスを吹き込み、十分水素含有量を低減させたのち、直
ちに凝固させる必要がある。Hydrogen atoms in the aluminum alloy segregate in the disordered portion of the atomic arrangement of the matrix. As a place where the atomic arrangement of the matrix phase is disturbed, grain boundaries, interfaces of crystallized substances and precipitates, or shear bands are raised. The segregated hydrogen atoms reduce the strength of the interface. Therefore, it was found that cracks are generated from these weakened interfaces as the starting point when the state is close to the molding limit. On the contrary, by maintaining the strength of these interfaces, it is possible to avoid deterioration of formability when the alloy of the present invention is positively improved in strength by precipitation treatment or the like. In order to maintain the strength of the crack initiation point, hydrogen content of less than 0.12 ml in 100 g of aluminum alloy,
More desirably, the amount of hydrogen is less than 0.1 ml. Especially, the influence becomes clear in the final ironing process of the DI molded can which is subjected to multi-stage molding. In order to obtain such a low hydrogen content, it is necessary to blow an inert gas sequentially immediately before casting to sufficiently reduce the hydrogen content and then immediately solidify it.

【０００７】[0007]

【実施例】以下本発明を実施例により更に詳細に説明す
る。表１に示す各組成のＡｌ合金溶湯を２段のフィルタ
ーに通し、５００mm厚の水冷鋳造鋳塊を作製した。ここ
で各々のフィルターにアルゴンガスを吹き込み、介在物
の除去とともに脱ガス処理を行った。これら鋳塊に６０
０℃で５時間の均質化処理を施した後、通常の熱間圧延
により３mm厚とし、４００℃の温度の焼鈍を２時間施
し、引き続いて冷間圧延により最終板厚０．３mmの圧延
板とした。これら供試材に対して水素含有量の測定と引
張試験およびＤＩ加工における割れ発生率を測定した。
通常の成形体の場合、塗装焼き付け処理を施された後の
材料の耐力値が特に問題となる。そこで試料の機械的性
能として焼き付け処理に対応する２００℃で１５分間の
熱処理後の耐力値を用いた。また成形性評価方法とし
て、ＤＩ加工は板厚減少率を６４％と一定にした条件に
て内容量が３５０mlの標準的な缶を１０００缶連続成形
し、この時の割れ発生缶数により評価した。評価基準と
しては割れ無し：優れる、１〜４缶割れ：現行並、５缶
以上割れ：劣るとした。表２にこれら試料の水素含有
量、引張性能および成形試験結果を示す。EXAMPLES The present invention will now be described in more detail with reference to examples. The molten Al alloys having the respective compositions shown in Table 1 were passed through a two-stage filter to prepare a water-cooled casting ingot having a thickness of 500 mm. Here, argon gas was blown into each filter to remove inclusions and perform degassing. 60 for these ingots
After homogenizing treatment at 0 ° C for 5 hours, normal hot rolling reduces the thickness to 3 mm, annealing at 400 ° C for 2 hours, and then cold rolling to obtain a final plate thickness of 0.3 mm. And For these test materials, the hydrogen content was measured, the tensile test was performed, and the crack generation rate in DI processing was measured.
In the case of an ordinary molded body, the proof stress value of the material after the paint baking treatment is particularly problematic. Therefore, as the mechanical performance of the sample, the proof stress value after the heat treatment for 15 minutes at 200 ° C. corresponding to the baking treatment was used. Further, as a method of evaluating the formability, the DI process was performed by continuously forming 1000 standard cans having a capacity of 350 ml under the condition that the plate thickness reduction rate was kept constant at 64%, and the number of cracked cans was evaluated. .. As evaluation criteria, no cracking: excellent, 1 to 4 cans cracking: current level, 5 or more cans cracking: inferior. Table 2 shows the hydrogen content, tensile performance and molding test results of these samples.

【０００８】[0008]

【表１】 [Table 1]

【０００９】[0009]

【表２】 [Table 2]

【００１０】表２から明らかなように本発明例No．１〜
３は成形性特にしごき加工性に優れるとともに強度の維
持が図られることが示される。これに対し水素含有量が
本発明の範囲より多い比較例No．４、５はしごき加工性
が現行並または劣ることが判る。As is apparent from Table 2, the invention example No. 1 to
No. 3 is excellent in moldability, especially ironing workability, and is able to maintain strength. On the other hand, Comparative Example No. 1 having a hydrogen content higher than the range of the present invention. It can be seen that the ironing workability of 4, 5 is as good as or lower than the current one.

【００１１】[0011]

【発明の効果】以上述べたように本発明ＤＩ成形用アル
ミニウム合金板は機械的強度を維持したまま、しごき加
工性が非常に優れている。そのため本発明アルミニウム
合金板を使用することにより、ＤＩ缶の生産性が向上す
るとともに、最近の厳しい成形条件、コストの低減の要
請に対応することができる。As described above, the aluminum alloy sheet for DI molding of the present invention is extremely excellent in ironing workability while maintaining mechanical strength. Therefore, by using the aluminum alloy sheet of the present invention, it is possible to improve the productivity of DI cans and meet the recent demands for severe molding conditions and cost reduction.

Claims

【特許請求の範囲】[Claims]

【請求項１】Ｍｎ０．８〜１．５wt％、Ｍｇ０．７〜
１．３wt％を含み、さらにＣｕ０．０５〜０．３wt％、
Ｓｉ０．１〜０．３wt％、Ｆｅ０．１〜０．７wt％、Ｚ
ｎ０．１〜０．２５wt％のうちの１種または２種以上を
含み、残部がＡｌと不可避的不純物とからなり、かつ水
素含有量が０．１２ml／１００ｇ未満であることを特徴
とするＤＩ成形用アルミニウム合金板。1. Mn 0.8-1.5 wt%, Mg 0.7-
1.3 wt%, and further 0.05-0.3 wt% Cu,
Si 0.1 to 0.3 wt%, Fe 0.1 to 0.7 wt%, Z
DI containing one or more of n0.1 to 0.25 wt%, the balance consisting of Al and inevitable impurities, and having a hydrogen content of less than 0.12 ml / 100 g. Aluminum alloy plate for forming.