JP5080150B2 - Manufacturing method of aluminum alloy plate for high-strength cap with excellent openability and ear rate - Google Patents

Description

この発明は、広口用ＰＰ（ｐｉｌｆｅｒ ｐｒｏｏｆ）キャップなどに適したキャップ用アルミニウム合金板の製造方法に関するものである。
The present invention relates to a method for producing an aluminum alloy plate for a cap suitable for a wide mouth PP (pillar proof) cap.

近年、ボトル缶等のアルミニウム合金製キャップとして、一旦開栓した後に再度封止可能であって、しかも一度開栓したことが容易に識別できるようにしたＰＰキャップが広く用いられるようになっている。この種のＰＰキャップの製造方法としては、一般には塗装および文字印刷を施したアルミニウム合金板を、カップ状に絞り成形した後、開口端をトリミングして裾部にミシン目を入れて製造するのが通常であり、さらにボトル本体部分に取付ける際にキャップの裾部にねじ溝が形成されるのが通常である。このようなＰＰキャップにおいては、前述のミシン目を、印刷文字をまたいで形成しておくことによって、一旦開栓した後には開栓履歴の有無を容易に識別できるようにするのが通常である。   In recent years, as caps made of aluminum alloys such as bottle cans, PP caps that can be re-sealed after being opened once and that can be easily identified once opened have been widely used. . As a manufacturing method of this type of PP cap, generally, an aluminum alloy plate that has been painted and printed with letters is drawn into a cup shape, and then the opening end is trimmed and perforated at the hem. In general, a screw groove is usually formed in the skirt of the cap when it is attached to the bottle body. In such a PP cap, it is usual to make it possible to easily identify the presence or absence of the opening history once it is opened by forming the perforations across the printed characters. .

ところでこの種のＰＰキャップ用のアルミニウム合金としては、従来は一般に成形性に優れたＪＩＳ Ａ１１００合金やＡ３１０５合金が用いられているが、最近では、缶の広口化の要請に伴なって、天面強度の低下を補うために高強度のＡｌ−Ｍｇ系合金が使用され始めている。このようなＰＰキャップ用の高強度Ａｌ−Ｍｇ系合金としては、例えば特許文献１、あるいは特許文献２に示されるようなものが提案されている。
特開２００３−３２８０６２号公報 特開２００６−４５６３８号公報 By the way, as an aluminum alloy for this type of PP cap, JIS A1100 alloy and A3105 alloy, which are generally excellent in formability, have been used conventionally. High-strength Al—Mg alloys have begun to be used to compensate for the decrease in strength. As such a high-strength Al—Mg alloy for PP caps, for example, those shown in Patent Document 1 or Patent Document 2 have been proposed.
JP 2003-328062 A JP 2006-45638 A

キャップ用アルミニウム合金板を高強度化させた場合、天面強度の向上には有効であるものの、材料の曲げ加工性が低下し、絞り加工後のネジ加工部の如く、厳しい加工が加わる箇所において塗膜の密着性が低下してしまう問題が生じる。そしてこのように塗膜の密着性が低下すれば、塗膜の剥離によってＰＰキャップにおいて大切な開栓履歴の識別機能が損なわれてしまうおそれがあり、したがってＰＰキャップにおいては、高強度を有すると同時に、曲げ加工性が優れていて塗膜の密着性が良好であることが望まれている。さらにＰＰキャップ用のアルミニウム合金板としては、キャップにおいてその裾部の印刷文字の曲がりが発生すれば、商品価値を損なうばかりでなく、開栓履歴の視認性が悪くなるから、絞り加工後の耳率を適切に制御することが望まれ、さらには開栓性が良好であること、特にキャップの裾部のミシン目の間の部分（ブリッジ）が低トルクで容易に引きちぎれることが望まれる。   When the aluminum alloy plate for caps is strengthened, it is effective in improving the top surface strength, but the bending workability of the material is reduced, and in places where severe processing is applied, such as threaded parts after drawing. The problem that the adhesiveness of a coating film falls arises. And, if the adhesion of the coating film is lowered in this way, there is a possibility that the identification function of the important opening history in the PP cap may be impaired due to the peeling of the coating film, and therefore, the PP cap has a high strength. At the same time, it is desired that the bending workability is excellent and the adhesion of the coating film is good. Furthermore, as an aluminum alloy plate for PP caps, if the printed characters at the bottom of the cap bend, not only will the product value be impaired, but the visibility of the opening history will deteriorate. It is desirable to appropriately control the rate, and further, it is desirable that the opening performance is good, and in particular, the portion (bridge) between the perforations at the bottom of the cap can be easily torn off with low torque.

しかしながら、特許文献１の提案では、具体的な耳率制御方法が明示されておらず、キャップ裾部の印刷文字の曲がりの発生を確実に抑制し得るか否かは不明であり、また強度も明示されていないため、望まれる高強度を達成し得るか否かの点も不明であり、さらには開栓性については全く考慮されていない。   However, in the proposal of Patent Document 1, a specific ear ratio control method is not clearly described, and it is unclear whether or not it is possible to reliably suppress the occurrence of bending of the printed characters at the cap skirt, and the strength is also unclear. Since it is not specified, it is also unclear whether or not the desired high strength can be achieved, and furthermore, no consideration is given to the unplugging property.

一方特許文献２の提案の場合も、開栓性に関しては全く配慮されておらず、また強度面でも未だ不充分であった。   On the other hand, in the case of the proposal of Patent Document 2, no consideration is given to the unplugging property, and the strength is still insufficient.

この発明は以上の事情を背景としてなされたもので、ＰＰキャップに適したＡｌ−Ｍｇ系合金板として、高強度を有するばかりでなく、耳率を適切に制御することにより印刷文字の曲がりの発生を確実に防止でき、しかも開栓性も良好なキャップ用アルミニウム合金板を製造する方法を提供することを課題とするものである。
This invention was made against the background described above, and as an Al-Mg alloy plate suitable for PP caps, it not only has high strength, but also generates bent characters by appropriately controlling the ear rate. It is an object of the present invention to provide a method for producing an aluminum alloy plate for a cap that can be reliably prevented and has good openability.

前述の課題を解決するべく鋭意実験・検討を重ねた結果、合金の成分組成を適切に調整するだけではなく、製造プロセス中の熱間圧延の条件および冷間圧延の条件、特に中間焼鈍を挟んで１次冷間圧延および仕上冷間圧延を行なう際の各冷間圧延における圧延率の比などを適切に制御することにより、耳率を適切に制御することができ、また耐力と引張強さとの比を適切に制御することによって良好な開栓性を確保できることを見出し、この発明をなすに至ったのである。   As a result of intensive experiments and studies to solve the above-mentioned problems, not only the alloy composition is adjusted appropriately, but also hot rolling conditions and cold rolling conditions during the manufacturing process, especially intermediate annealing are sandwiched. By appropriately controlling the ratio of the rolling ratio in each cold rolling at the time of performing the primary cold rolling and the finish cold rolling, the ear ratio can be controlled appropriately, and the yield strength and tensile strength As a result, the inventors have found that a good openability can be ensured by appropriately controlling the ratio of the above, and have led to the present invention.

具体的には、請求項１の発明の高強度キャップ用アルミニウム合金板の製造方法は、Ｍｇ１．５〜２．１％（ｍａｓｓ％、以下同じ）、Ｆｅ０．１〜０．４％、Ｓｉ０．０５〜０．３％、Ｍｎ０．１％以下（０％を含む）を含有し、残部がＡｌおよび不可避不純物からなるＡｌ合金の鋳塊に均質化処理を施した後、熱間粗圧延と熱間仕上げ圧延からなる熱間圧延を行なうにあたり、熱間仕上げ圧延における最終パスの歪み速度を９０ｓｅｃ^-1以上、熱間仕上圧延終了温度を３３０℃以上とし、得られた熱間圧延コイルを、２８０℃以上の温度域に３時間以上保持される冷却速度で冷却して、熱延板の再結晶率を９５％以上とし、次いで熱間圧延板に、圧延率Ｒ１の１次冷間圧延、中間焼鈍、圧延率Ｒ２の仕上冷間圧延をその順に施すにあたり、１次冷間圧延率Ｒ１と仕上冷間圧延率Ｒ２とが次式
１．３０×Ｒ２（％）≦Ｒ１（％）≦１．６０×Ｒ２（％）
を満たしかつ仕上冷間圧延率Ｒ２が４５〜５５％の範囲内となるように、１次冷間圧延と仕上冷間圧延を行なうとともに、その間の中間焼鈍を、到達温度４００〜５５０℃で２分以内保持の条件で行ない、仕上冷間圧延後、１７０〜２４０℃で０．５〜１２時間保持する安定化処理を施し、これによって、引張強さが１９０〜２５０ＭＰａであり、かつ耐力／引張強さの比が０．７５〜０．８５の範囲内にあり、しかも耳率が、４５°耳で２％以下であるキャップ用アルミニウム合金を得ることを特徴とするものである。
Specifically, the manufacturing method of the aluminum alloy plate for a high-strength cap according to the first aspect of the present invention is Mg 1.5 to 2.1% (mass%, the same applies hereinafter) , Fe 0.1 to 0.4%, Si 0. After subjecting the ingot of Al alloy containing 05-0.3% and Mn 0.1% or less (including 0%) to the balance consisting of Al and inevitable impurities, hot rough rolling and heat In performing hot rolling comprising hot finish rolling, the final pass strain rate in hot finish rolling is 90 sec ⁻¹ or more, the hot finish rolling finish temperature is 330 ° C. or more, and the obtained hot rolled coil is 280 The steel sheet is cooled at a cooling rate that is maintained in a temperature range of 3 ° C. or more for 3 hours or more, and the recrystallization rate of the hot-rolled sheet is set to 95% or more. Annealing and finishing cold rolling with a rolling rate R2 are performed in that order. , Primary cold rolling rate R1 and finish cold rolling ratio R2 and the following formula
1.30 × R2 (%) ≦ R1 (%) ≦ 1.60 × R2 (%)
Are satisfied, and the finish cold rolling rate R2 is in the range of 45 to 55%, and the primary cold rolling and the finish cold rolling are performed, and the intermediate annealing is performed at an ultimate temperature of 400 to 550 ° C. conducted under conditions of retention within a minute, finish after cold-rolling, and facilities the stabilization process of holding 0.5 to 12 hours at 170 to 240 ° C., whereby the tensile strength is 190～250MPa, and yield strength / A cap aluminum alloy having a tensile strength ratio in the range of 0.75 to 0.85 and an ear rate of 2% or less at 45 ° ears is obtained .

この発明の製造方法により得られたキャップ用アルミニウム合金板は、高強度を有していて耐圧強度に優れるばかりでなく、耳率が安定して良好で、キャップ裾部における印刷文字の曲がりの発生を有効に防止でき、さらには開栓性も良好であって、表面品質に優れており、したがって特にＰＰキャップ用として好適に使用することができる。
The aluminum alloy plate for caps obtained by the production method of the present invention has high strength and excellent pressure strength, and also has a stable and good ear rate and the occurrence of bending of printed characters at the cap hem. Can be effectively prevented, and furthermore, the openability is good and the surface quality is excellent. Therefore, it can be suitably used particularly for PP caps.

先ずこの発明におけるアルミニウム合金の成分組成の限定理由について説明する。   First, the reasons for limiting the component composition of the aluminum alloy in the present invention will be described.

Ｍｇ：
Ｍｇは、キャップ用のＡｌ−Ｍｇ系アルミニウム合金として必要な強度を付与するために不可欠な元素である。Ｍｇ量が１．５％未満では強度付与の効果が充分に得られず、一方Ｍｇ量が２．１％を越えれば、強度が高くなり過ぎて、キャップとして開栓が困難となるおそれがある。そこでＭｇ量は１．５〜２．１％の範囲内とした。 Mg:
Mg is an indispensable element for imparting necessary strength as an Al—Mg-based aluminum alloy for caps. If the Mg content is less than 1.5%, the effect of imparting strength cannot be sufficiently obtained. On the other hand, if the Mg content exceeds 2.1%, the strength becomes too high and it is difficult to open the cap as a cap. . Therefore, the Mg content is set in the range of 1.5 to 2.1%.

Ｆｅ：
Ｆｅは、晶出物を形成してキャップとしての開栓性の改善に寄与する。Ｆｅ量が０．１％未満ではその効果が充分に得られず、開栓性が悪くなってしまうおそれがある。一方Ｆｅ量が０．４％を越えれば、４５°方向の耳（４５°耳率）が高くなり、印刷文字の曲がりが生じてしまうおそれがある。そこでＦｅ量は０．１〜０．４％の範囲内とした。 Fe:
Fe forms a crystallized substance and contributes to the improvement of the openability as a cap. If the amount of Fe is less than 0.1%, the effect cannot be obtained sufficiently, and the openability may be deteriorated. On the other hand, if the amount of Fe exceeds 0.4%, the ears in the 45 ° direction (45 ° ear rate) become high, and the printed characters may be bent. Therefore, the amount of Fe is set in the range of 0.1 to 0.4%.

Ｍｎ：
Ｍｎは強度向上に寄与する元素であるが、Ｍｎ量が０．１％を越えれば、４５°耳が高くなって、印刷文字の曲がりを引起すおそれがあり、そこでＭｎ量は０．１％以下（０％を含む）に規制することとした。 Mn:
Mn is an element that contributes to strength improvement. If the amount of Mn exceeds 0.1%, the 45 ° ear becomes high, and there is a risk of causing bending of printed characters. It was decided to regulate to the following (including 0%).

Ｓｉ：
Ｓｉも晶出物を形成して、キャップとしての開栓性の向上に寄与する。Ｓｉ量が０．０５％未満では開栓性向上の効果が充分に得られず、一方Ｓｉ量が０．３％を越えれば、４５°耳が発生して印刷文字の曲がりを招くおそれがある。そこでＳｉ量は０．０５〜０．３％の範囲内とした。 Si:
Si also forms a crystallized product and contributes to the improvement of the opening performance as a cap. If the amount of Si is less than 0.05%, the effect of improving the openability cannot be sufficiently obtained. On the other hand, if the amount of Si exceeds 0.3%, a 45 ° ear may be generated and the printed characters may be bent. . Therefore, the Si amount is set in the range of 0.05 to 0.3%.

以上の各元素のほかは、基本的にはＡｌおよび不可避的不純物とすれば良いが、通常のＡｌ合金において添加されることが多いＴｉ、Ｂ、あるいはＣｒ、Ｖ、Ｚｒ、Ｃｕ、Ｚｎ等の元素も、特性に大きな影響を与えない範囲内で含有することは許容される。例えば鋳造時の微細化剤として添加されることが多いＴｉ、Ｂは、それぞれ０．０５％以下、０．０１％以下であれば許容され、また強度上昇に効果があるとされるＣｒ、Ｖ、Ｚｒはそれぞれ０．１％以下、Ｃｕは０．２５％以下、Ｚｎは１．０％以下であれば許容される。   In addition to the above elements, basically, Al and inevitable impurities may be used. However, Ti, B, or Cr, V, Zr, Cu, Zn, etc., which are often added in ordinary Al alloys, are used. It is permissible for the elements to be contained within a range that does not significantly affect the characteristics. For example, Ti and B, which are often added as a finer during casting, are allowed to be 0.05% or less and 0.01% or less, respectively, and Cr and V are considered to be effective in increasing the strength. , Zr is 0.1% or less, Cu is 0.25% or less, and Zn is 1.0% or less, respectively.

さらにこの発明のキャップ用アルミニウム合金板においては、製品板の引張強さ（抗張力）が１９０〜２５０ＭＰａの範囲内であることが必要である。製品板の引張強さが１９０ＭＰａ未満では、キャップの天面強度が不充分となって、特に広口用のＰＰキャップとして不適当となる。一方、製品板の引張強さが２５０ＭＰａを越えれば、開栓時において特にブリッジが切れる際のトルク値が高くなり、開栓性が悪化してしまう。そこでこの発明では、広口用ＰＰキャップとして必要な天面強度を維持しつつ開栓性の向上を図るため、製品板の引張強さを１９０〜２５０ＭＰａの範囲内に規制することとした。   Furthermore, in the aluminum alloy plate for a cap of the present invention, the product plate needs to have a tensile strength (tensile strength) in the range of 190 to 250 MPa. When the tensile strength of the product plate is less than 190 MPa, the top surface strength of the cap is insufficient, and it is particularly inappropriate as a PP cap for a wide mouth. On the other hand, if the tensile strength of the product plate exceeds 250 MPa, the torque value when the bridge is broken particularly at the time of opening is increased, and the opening performance is deteriorated. Therefore, in the present invention, the tensile strength of the product plate is regulated within the range of 190 to 250 MPa in order to improve the opening performance while maintaining the top surface strength necessary for the PP cap for the wide mouth.

また一方この発明のキャップ用アルミニウム合金板では、巻き締め時における天面の絞りやネジ部の深さを適正に制御し、ひいては開栓性と耐圧強度とを両立させるために製品板の耐力値と引張強さとの比率を規制することとしている。すなわち、耐力値／引張強さの比の値が０．７５未満では、巻き締め時においてネジ部の深さが深くなりすぎて、開栓時のトルクが高くなり、一方耐力値／引張強さの比の値が０．８５を越えれば、巻き締め時における天面の絞りやネジ部の深さが浅くなり、耐圧強度が低下してしまう。そこでこの発明のキャップ用アルミニウム合金板においては、耐力値／引張強さの比を０．７５〜０．８５の範囲内に規制することとした。   On the other hand, in the aluminum alloy plate for caps of the present invention, the squeezing value of the product plate is properly controlled in order to properly control the aperture of the top surface and the depth of the screw portion at the time of winding, and to achieve both the opening performance and the pressure strength. And the ratio between the tensile strength and the tensile strength. That is, when the ratio of the proof stress value / tensile strength ratio is less than 0.75, the screw portion becomes too deep during winding and the torque at the time of opening is increased, while the proof stress value / tensile strength is high. If the value of the ratio exceeds 0.85, the top surface of the top surface and the depth of the screw portion at the time of tightening become shallow, and the pressure resistance is reduced. Therefore, in the aluminum alloy plate for a cap of the present invention, the ratio of the proof stress value / tensile strength is regulated within the range of 0.75 to 0.85.

さらにこの発明のキャップ用アルミニウム合金板では、製品板における４５°方向の耳率（４５°耳）を２％以下とする必要がある。４５°耳が２％を越えれば、キャップとして印刷文字の曲がりを引起すおそれがある。なおここで、４５°耳について２％以下と規定したのは、たとえ全体として耳率が２％以下であっても、０−１８０°耳が強くなれば、印刷文字の曲がりが生じてしまうおそれがあるからである。   Furthermore, in the aluminum alloy plate for caps of the present invention, the ear rate (45 ° ear) in the 45 ° direction of the product plate needs to be 2% or less. If the 45 ° ear exceeds 2%, the printed character may be bent as a cap. The reason why the 45 ° ear is defined as 2% or less is that even if the ear rate is 2% or less as a whole, if the 0-180 ° ear becomes strong, the printed characters may be bent. Because there is.

さらにこの発明のキャップ用アルミニウム合金板においては、その圧延方向と平行な断面における晶出物面積率が０．５〜１．５％の範囲内にあることが望ましい。すなわち、晶出物面積率が０．５％未満の場合は、開栓時におけるブリッジで破断トルクが高くなり過ぎて、開栓性が悪くなるおそれがあり、一方晶出物面積率が１．５％を越えれば、開栓時におけるブリッジ破断トルクは適正であっても、４５°耳が高くなり過ぎて、印刷文字曲がりが生じてしまうおそれがある。   Furthermore, in the aluminum alloy plate for caps of this invention, it is desirable that the crystallized area ratio in the cross section parallel to the rolling direction is in the range of 0.5 to 1.5%. That is, when the crystallized area ratio is less than 0.5%, the breaking torque becomes too high at the bridge at the time of opening, and the openability may be deteriorated. If it exceeds 5%, even if the bridge breaking torque at the time of opening is appropriate, the 45 ° ear becomes too high, and there is a possibility that the printed character will be bent.

次にこの発明のキャップ用アルミニウム合金板の製造方法について説明する。   Next, the manufacturing method of the aluminum alloy plate for caps of this invention is demonstrated.

先ず前述のような成分組成のアルミニウム合金を、ＤＣ鋳造法などの常法にしたがって鋳造し、得られた鋳塊に対して均質化処理を施す。均質化処理の条件については特に限定しないが、鋳造偏析解消のため４５０℃以上（通常は５５０℃以下）の温度で、１時間以上（通常は１２時間以内）保持する条件で行なうことが好適である。   First, an aluminum alloy having the above-described component composition is cast according to a conventional method such as a DC casting method, and the resulting ingot is homogenized. There are no particular restrictions on the conditions for the homogenization treatment, but it is preferable to carry out the conditions at a temperature of 450 ° C. or higher (usually 550 ° C. or lower) for 1 hour or longer (usually within 12 hours) to eliminate casting segregation. is there.

均質化処理後には熱間圧延を施すが、この熱間圧延は、均質化処理後、冷却することなく直ちに開始しても、あるいは均質化処理後に再加熱して行なっても良い。この熱間圧延は、熱間圧延を終了した熱延板コイルの状態（熱延後コイルに巻取って冷却し、室温もしくは室温付近の温度まで冷却した状態）で、熱延板の再結晶率が９５％以上であることが重要である。すなわち、熱延板に未再結晶部分が混在すれば、その後の１次冷間圧延後の中間焼鈍時に立方体方位（キューブ方位）が過度に発達し、最終製品板の０−１８０°耳が強くなって、キャップとして印刷文字の曲がりが発生してしまうおそれがあり、それを防止するために、熱延板の再結晶率を９５％以上に制御する必要がある。   Although hot rolling is performed after the homogenization treatment, this hot rolling may be started immediately without cooling after the homogenization treatment, or may be performed by reheating after the homogenization treatment. This hot rolling is performed in the state of the hot rolled sheet coil after the hot rolling is finished (the state after being wound around the coil after being rolled and cooled and cooled to a temperature at or near room temperature). Is 95% or more. That is, if non-recrystallized portions are mixed in the hot-rolled sheet, the cube orientation (cube orientation) develops excessively during the subsequent intermediate annealing after the primary cold rolling, and the final product plate has a strong 0-180 ° ear. Therefore, there is a possibility that the printed characters may be bent as a cap, and in order to prevent this, it is necessary to control the recrystallization rate of the hot-rolled sheet to 95% or more.

そこで熱間圧延の条件も、主として最終的に熱延板の再結晶率が９５％以上となるように制御する観点から定めている。   Therefore, the hot rolling conditions are also determined mainly from the viewpoint of controlling the hot rolled sheet so that the recrystallization rate is finally 95% or more.

すなわち熱間圧延は粗圧延および仕上圧延によって行なうのが通常であり、そのうち仕上圧延は、複数回のパスで行なうのが通常であるが、この発明の場合、仕上圧延における最終パス（ラストパス）を、歪み速度が９０ｓｅｃ^-1となるように行ない、また仕上圧延最終パスの終了温度を、３３０℃以上とし、さらに仕上圧延を終了して巻き取られた熱延板コイルについては、２８０℃以上の温度域に３時間以上保持される冷却速度で冷却することとする。 That is, hot rolling is usually performed by rough rolling and finish rolling, and finishing rolling is usually performed in a plurality of passes. In the case of the present invention, the final pass (last pass) in finish rolling is used. In addition, for the hot rolled sheet coil wound up after finishing the finishing rolling, the finishing temperature of the final pass of the final rolling is set to 330 ° C. or higher, so that the strain rate is 90 sec ⁻¹ . Cooling is performed at a cooling rate that is maintained in the temperature range for 3 hours or more.

これらの熱間圧延条件の限定理由は次の通りである。   The reasons for limiting these hot rolling conditions are as follows.

すなわち、熱間仕上げ圧延の最終パスの歪み速度が９０ｓｅｃ^-1未満では、熱間圧延直後の板の歪みが充分ではなく、熱延後の再結晶率を９５％以上とすることが困難となって、最終板の耳が、強い０−１８０°耳傾向となり、キャップにおける印刷文字の曲がりが発生するおそれがあり、そこで最終パスの歪み速度を９０ｓｅｃ^-1以上と規定した。なお最終パスの歪み速度は、圧下量、圧延速度だけでなく、ロール半径や圧延荷重等の影響も受けるのが通常であり、そこでこれらの因子を適切に組合せることによって制御することができる。 That is, if the strain rate of the final pass of hot finish rolling is less than 90 sec ⁻¹ , the strain of the plate immediately after hot rolling is not sufficient, and it becomes difficult to set the recrystallization rate after hot rolling to 95% or more. Then, the ears of the final plate tend to have a strong 0-180 ° ear tendency, and there is a possibility that the printed characters may be bent in the cap. Therefore, the distortion speed of the final pass is defined as 90 sec ⁻¹ or more. The strain rate in the final pass is usually affected not only by the rolling amount and rolling speed but also by the roll radius and rolling load, and can be controlled by appropriately combining these factors.

また熱間圧延終了温度が３３０℃未満でも、熱間圧延終了板の再結晶率を９５％以上とすることが困難となり、前記同様に最終板の耳が、強い０−１８０°耳傾向となってキャップにおける印刷文字の曲がりが発生するおそれがあり、そこで熱間圧延終了温度を３３０℃以上と規定した。   Even if the hot rolling end temperature is less than 330 ° C., it becomes difficult to set the recrystallization rate of the hot rolled end plate to 95% or more, and the end of the final plate tends to have a strong 0-180 ° ear tendency as described above. Therefore, the printed characters may be bent in the cap, and the hot rolling end temperature is defined as 330 ° C. or higher.

さらに、熱間圧延を終了して巻取ったコイルを、２８０℃以上の温度域に３時間以上保持されるような冷却速度条件で冷却するのは、熱延板コイルを高温状態に長時間保持して熱延板の再結晶を充分に進行させるためであり、これを越える冷却速度で熱延板コイルを冷却すれば、熱間圧延終了板の再結晶率を９５％以上とすることが困難となってしまう。なおこのような冷却速度は、コイル冷却用のファンの風量等の条件を調整したり、あるいは積極的に熱延板コイルを保温したりすることにより達成可能である。   Furthermore, the coil that has been wound after the completion of the hot rolling is cooled under a cooling rate condition such that the coil is kept in a temperature range of 280 ° C. or more for 3 hours or more. Therefore, if the hot-rolled sheet coil is cooled at a cooling rate exceeding this, it is difficult to increase the recrystallization rate of the hot-rolled finished sheet to 95% or more. End up. Such a cooling rate can be achieved by adjusting the conditions such as the air volume of the coil cooling fan, or by actively keeping the hot rolled sheet coil warm.

上述のようにして９５％以上の再結晶率で再結晶した熱延板に対しては、冷間圧延を施して所定の製品板厚とする。ここで、この発明の場合、冷間圧延は１次冷間圧延および仕上冷間圧延（最終冷間圧延）によって行ない、かつ１次冷間圧延と仕上冷間圧延との間に中間焼鈍を施す。このような冷間圧延の条件はこの発明にとって重要であり、１次冷間圧延の圧延率（％）をＲ１、仕上冷間圧延の圧延率（％）をＲ２とすれば、Ｒ１がＲ２に対し、次式
１．３０×Ｒ２（％）≦Ｒ１（％）≦１．６０×Ｒ２（％）
を満たすように施す必要がある。このように１次冷間圧延率Ｒ１を仕上冷間圧延率Ｒ２と関係させて定めた理由は次の通りである。 The hot-rolled sheet recrystallized at a recrystallization rate of 95% or more as described above is cold-rolled to a predetermined product sheet thickness. Here, in the case of the present invention, cold rolling is performed by primary cold rolling and finish cold rolling (final cold rolling), and intermediate annealing is performed between primary cold rolling and finish cold rolling. . Such cold rolling conditions are important for the present invention. If the rolling rate (%) of the primary cold rolling is R1, and the rolling rate (%) of the finish cold rolling is R2, then R1 becomes R2. On the other hand,
1.30 × R2 (%) ≦ R1 (%) ≦ 1.60 × R2 (%)
It is necessary to apply to satisfy. The reason why the primary cold rolling rate R1 is thus determined in relation to the finish cold rolling rate R2 is as follows.

中間焼鈍前の冷間圧延率（１次冷間圧延率Ｒ１）は、中間焼鈍時の再結晶集合組織に占める０−９０°耳成分と相関し、中間焼鈍後の仕上冷間圧延中に発達する４５°耳成分とバランスを取るためには、上記の式を満足させる必要がある。すなわちＲ１が１．３０×Ｒ２未満であれば、中間焼鈍時に形成される再結晶集合組織における０−９０°耳成分となる方位密度が充分でないため、最終板の耳が４５°方向で強すぎ、キャップとして印刷文字曲がりが発生するおそれがある。一方Ｒ１が１．６０×Ｒ２を越えれば、逆に最終板の耳が０−９０°耳側となり、０°位置でキャップとして印刷文字曲がりが発生するおそれがある。   The cold rolling rate before intermediate annealing (primary cold rolling rate R1) correlates with the 0-90 ° ear component in the recrystallized texture during intermediate annealing, and develops during finish cold rolling after intermediate annealing. In order to balance with the 45 ° ear component, it is necessary to satisfy the above formula. That is, if R1 is less than 1.30 × R2, the orientation density that becomes the 0-90 ° ear component in the recrystallized texture formed during the intermediate annealing is not sufficient, so the ear of the final plate is too strong in the 45 ° direction. The printed character may be bent as a cap. On the other hand, if R1 exceeds 1.60 × R2, the end of the final plate is on the 0-90 ° ear side, and the printed character may be bent as a cap at the 0 ° position.

１次冷間圧延後の中間焼鈍としては、４００〜５５０℃の範囲内の温度で２分以内（０秒を含む）保持する焼鈍を行なう。このような高温短時間の中間焼鈍は、連続焼鈍炉を用いて実施するのが通常である。ここで中間焼鈍における加熱温度が４００℃未満では、連続焼鈍炉の場合再結晶状態とすることが困難となり、最終板の強度が異常に高くなって開栓性が悪くなるとともに、曲げ加工性が著しく低下して、塗膜密着性が低下するおそれがあり、さらには、本来発達させるべき立方体方位が発達しないため、４５°耳が強くなってしまうおそれがある。一方中間焼鈍の加熱温度が５５０℃を越えたり、２分を越える長時間の保持を行なえば、再結晶粒が粗大化して成形後肌荒れが生じるおそれがあり、またこのような結晶粒の粗大化の際には、立方体方位が強くなりすぎて最終板の０−１８０°耳が強くなり、キャップとして印刷文字の曲がりが発生するおそれがある。   As the intermediate annealing after the primary cold rolling, annealing is performed at a temperature within a range of 400 to 550 ° C. for 2 minutes (including 0 seconds). Such high temperature and short time intermediate annealing is usually carried out using a continuous annealing furnace. Here, when the heating temperature in the intermediate annealing is less than 400 ° C., it is difficult to obtain a recrystallized state in the case of a continuous annealing furnace, the strength of the final plate becomes abnormally high, the pluggability is deteriorated, and the bending workability is reduced. There is a risk that the coating film adhesion may be significantly reduced, and further, the cubic orientation that should be originally developed does not develop, so that the 45 ° ear may be strengthened. On the other hand, if the heating temperature of the intermediate annealing exceeds 550 ° C. or holding for a long time exceeding 2 minutes, the recrystallized grains may be coarsened to cause roughening after molding. In this case, the cube orientation becomes too strong, and the 0-180 ° ear of the final plate becomes strong, and there is a possibility that the printed characters bend as a cap.

中間焼鈍後に行なう仕上冷間圧延（最終冷間圧延）は、その圧延率Ｒ２を４５〜５５％の範囲内とする必要がある。これは、仕上冷間圧延率Ｒ２が４５％未満では強度が不足して、広口用として耐圧強度が不足し、一方５５％を越えれば強度が高くなりすぎて開栓時のトルクが高くなりすぎるおそれがあるからである。なお、仕上冷間圧延の圧延率Ｒ２は、１次冷間圧延の圧延率Ｒ１との関係で前述の式を満たす必要があることはもちろんである。   The finish cold rolling (final cold rolling) performed after the intermediate annealing needs to have a rolling rate R2 in the range of 45 to 55%. This is because when the finish cold rolling rate R2 is less than 45%, the strength is insufficient, and the pressure resistance for the wide opening is insufficient, while when it exceeds 55%, the strength becomes too high and the torque at the time of opening is too high. Because there is a fear. Of course, the rolling rate R2 of the finish cold rolling needs to satisfy the above-described formula in relation to the rolling rate R1 of the primary cold rolling.

仕上冷間圧延により所定の製品板厚とした後には、安定化処理を行なう。この安定化処理は通常は箱型焼鈍炉を用いてバッチ式で行なう。この安定化処理は、１７０〜２４０℃の範囲内の温度で０．５〜１２時間保持するものとする。ここで、安定化処理の加熱保持が１７０℃未満、あるいは０．５時間未満では、転位の整理が充分ではなく、そのため耐力値／引張強さの比が０．８５を越えて、巻締め時に天面の絞りやネジ部の深さが浅くなり、耐圧強度が低下してしまうおそれがある。一方安定化処理の加熱温度が２４０℃を越えれば、耐力値／引張強さの比が０．７５未満となり、巻締め時にネジ部が深くなり過ぎて、開栓時のトルクが上昇し、開栓性が劣ってしまう。なお安定化処理の加熱処理時間が１２時間を越えても極端な変化はないが、コストが上昇して工業的に不利となる。   After a predetermined product thickness is obtained by finish cold rolling, a stabilization process is performed. This stabilization treatment is usually carried out batchwise using a box-type annealing furnace. This stabilization treatment shall be held at a temperature in the range of 170 to 240 ° C. for 0.5 to 12 hours. Here, if the heat retention during the stabilization treatment is less than 170 ° C. or less than 0.5 hours, dislocations are not sufficiently arranged, and therefore the ratio of the proof stress value / tensile strength exceeds 0.85 and during the tightening. There is a risk that the aperture and the threaded portion of the top surface become shallow and the pressure resistance is reduced. On the other hand, if the heating temperature of the stabilization process exceeds 240 ° C., the ratio of the proof stress / tensile strength becomes less than 0.75, the screw part becomes too deep when tightening, and the torque at the time of opening increases. The plugging property is inferior. Even if the heat treatment time for the stabilization treatment exceeds 12 hours, there is no extreme change, but the cost increases and this is industrially disadvantageous.

以上のように、熱間圧延の最終パスの歪み速度、熱間仕上圧延終了温度、および熱延板巻取コイルの冷却速度を適切に制御して、再結晶率９５％以上の熱延板を得、さらに１次冷間圧延率Ｒ１および仕上冷間圧延率Ｒ２を相互の関係のもとに適切に制御し、さらに適切な安定化処理を施すことによって、最終的に耳率が良好でキャップとしての印刷文字の曲がりの発生がなく、かつ開栓性も良好で、しかも高強度で、特に広口用のキャップとして充分な天面強度を有するキャップ用アルミニウム合金板を得ることが可能となったのである。   As described above, a hot rolled sheet having a recrystallization rate of 95% or more can be controlled by appropriately controlling the strain rate of the final pass of hot rolling, the finish temperature of hot finish rolling, and the cooling rate of the hot rolled sheet winding coil. In addition, the primary cold rolling rate R1 and the finish cold rolling rate R2 are appropriately controlled based on the mutual relations and further subjected to an appropriate stabilization process, so that the ear rate is finally good and the cap is obtained. As a result, it is possible to obtain an aluminum alloy plate for a cap that has no bending of printed characters, has a good openability, and has a high strength, particularly a top surface strength sufficient for a wide mouth cap. It is.

以下この発明の実施例を説明する。   Examples of the present invention will be described below.

表１の合金符号Ａ〜Ｉに示す各成分組成の合金を常法により溶解鋳造して、厚さ５００ｍｍのスラブ（板状鋳塊）を得た。得られた鋳塊に対し、５００℃×４ｈｒの均質化処理を施した後、熱間圧延（粗圧延および仕上圧延）を行なってコイルに巻取り、さらに１次冷間圧延、中間焼鈍、仕上冷間圧延（最終冷間圧延）を行ない、さらに仕上焼鈍として安定化処理を行なった。ここで、熱間圧延については、粗圧延をシングルのリバース式圧延機により、開始温度４７０℃で行ない、仕上げ圧延を４スタンドのタンデム式圧延機で行なった。また中間焼鈍には連続式焼鈍炉（ＣＡＬ）を用いた。さらに仕上げ焼鈍には、箱型焼鈍炉（バッチ炉）を用いた。なお最終板厚は０．２５ｍｍとした。熱間仕上圧延、１次冷間圧延、中間焼鈍、仕上冷間圧延（最終冷間圧延）、安定化処理（仕上焼鈍）の具体的な条件を表２の製造番号１〜２１に示す。なお、熱間圧延後、コイルに巻取った状態では、冷却用ファンの調整により熱延板コイルの冷却速度を調整した。   Alloys having respective component compositions shown in alloy codes A to I in Table 1 were melt-cast by a conventional method to obtain a slab (plate ingot) having a thickness of 500 mm. The obtained ingot is subjected to a homogenization treatment of 500 ° C. × 4 hr, followed by hot rolling (coarse rolling and finish rolling) and winding into a coil, followed by primary cold rolling, intermediate annealing, finishing Cold rolling (final cold rolling) was performed, and a stabilization treatment was performed as finish annealing. Here, for hot rolling, rough rolling was performed with a single reverse rolling mill at a starting temperature of 470 ° C., and finish rolling was performed with a four-stand tandem rolling mill. Moreover, the continuous annealing furnace (CAL) was used for the intermediate annealing. Further, a box-type annealing furnace (batch furnace) was used for finish annealing. The final plate thickness was 0.25 mm. Specific conditions of hot finish rolling, primary cold rolling, intermediate annealing, finish cold rolling (final cold rolling), and stabilization treatment (finish annealing) are shown in production numbers 1 to 21 in Table 2. In addition, after the hot rolling, in the state wound around the coil, the cooling rate of the hot-rolled sheet coil was adjusted by adjusting the cooling fan.

以上のような製造プロセス中において、熱間圧延後にコイルに巻取って室温まで冷却した熱間圧延板からサンプルを切出し、熱間圧延板の再結晶率を調べたので、その結果を表３中に示した。ここで、熱間圧延板の再結晶率は、横断面について研磨後にバーカー法で写真撮影を行い、全板厚中に再結晶部分の占める割合を測定した。   During the manufacturing process as described above, a sample was cut out from a hot rolled plate that had been wound into a coil after hot rolling and cooled to room temperature, and the recrystallization rate of the hot rolled plate was examined. It was shown to. Here, the recrystallization rate of the hot-rolled sheet was measured by taking a photo with the Barker method after polishing the cross section and measuring the ratio of the recrystallized portion in the total thickness.

また前述のようにして得られた製品板について、引張試験を行なって引張強さおよび耐力を調べるるとともに、耐力値／引張強さの比を求めた。さらに耳率を測定し、その結果を表３中に示した。引張試験および耳率の測定方法は次の通りである。   Further, the product plate obtained as described above was subjected to a tensile test to examine the tensile strength and the yield strength, and the ratio of the yield strength / tensile strength was determined. Further, the ear rate was measured, and the results are shown in Table 3. The tensile test and the method of measuring the ear rate are as follows.

引張試験：
ＪＩＳ５号試験片を使用して圧延方向と平行方向で引張試験を実施した。 Tensile test:
A tensile test was performed in the direction parallel to the rolling direction using JIS No. 5 test pieces.

耳率：
パンチ径３３ｍｍ、パンチ肩Ｒ１．５ｍｍ、ブランク径５７ｍｍ、しわ押さえ２５０ｋｇｆでカップ成形し、次式を用いて計算した。
耳率＝（山平均−谷平均）／カップ平均高さ×１００（％） Ear rate:
A cup was formed with a punch diameter of 33 mm, a punch shoulder R of 1.5 mm, a blank diameter of 57 mm, and a wrinkle presser of 250 kgf, and calculation was performed using the following formula.
Ear rate = (mountain average-valley average) / cup average height x 100 (%)

なお耳率の値については、０°、９０°位置と４５°位置を比較して０°、９０°位置が高い場合をマイナス、４５°位置が高い場合をプラスで表記した。なおここで、４５°耳率は２．０％以下である必要があり、また０−９０°耳が高い場合（マイナス耳）も許容されない。   As for the value of the ear rate, the 0 °, 90 ° position and the 45 ° position are compared, and the case where the 0 °, 90 ° position is high is expressed as minus, and the case where the 45 ° position is high is expressed as plus. Here, the 45 ° ear rate needs to be 2.0% or less, and the case where the 0-90 ° ear is high (minus ear) is not allowed.

さらに、前述のようにして得られた製品板に塗装処理を施して、プレス、ロール成形により直径３８ｍｍφのキャップを作製した後、外観観察を行なって成形上の問題がないか確認した後、容器に巻き締めて、その開栓トルクおよび耐圧強度を測定したので、それらの結果を表３中に示す。   Furthermore, after applying the coating treatment to the product plate obtained as described above and producing a cap with a diameter of 38 mmφ by press and roll molding, the appearance is observed to confirm that there is no molding problem, and then the container The opening torque and pressure strength were measured, and the results are shown in Table 3.

これらのキャップ外観品質、開栓トルクおよび耐圧強度についての測定もしくは評価方法は次の通りである。   The measurement or evaluation method for these cap appearance quality, opening torque and pressure strength is as follows.

外観観察：
特に問題がないものを良好と判定して○印を付し、肌荒れやフローマークが生じたものは不良として×印を付した。 Appearance observation:
Those with no particular problem were judged as good and marked with ○, and those with rough skin or flow marks were marked as bad.

耐圧強度：
容器が内圧で反転しないように拘束した状態で窒素ボンベから窒素ガスで加圧し、キャップからガスが漏れ始める圧力を測定した。この圧力が１３ｋｇｆ／ｃｍ²以上を良好と判定して○印を付し、１３ｋｇｆ／ｃｍ²未満の場合は強度不足として×印を付した。 Pressure strength:
In a state where the container was constrained so as not to be reversed by the internal pressure, nitrogen gas was pressurized with nitrogen gas, and the pressure at which gas began to leak from the cap was measured. When this pressure was 13 kgf / cm ² or more, it was determined that the pressure was good, and a mark “◯” was given. When the pressure was less than 13 kgf / cm ² , an X mark was given as insufficient strength.

開栓トルク：
キャップが容器に対し回転し始めるトルク（＃１）と、最初にブリッジが切れる際のトルク（＃２）を測定した。＃１トルク、＃２トルクのいずれについても、１５０Ｎ・ｃｍ以下の場合を開栓性良好と判定して○印を付し、１５０Ｎ・ｃｍを越えた場合は開栓性不良と判定して×印を付した。 Opening torque:
The torque (# 1) at which the cap starts rotating with respect to the container and the torque (# 2) when the bridge is first cut were measured. For both # 1 torque and # 2 torque, the case of 150 N · cm or less is judged as being good in opening performance, and a ○ mark is given. Marked.

表３から明らかなように製造番号１〜４のこの発明の範囲内のものは、全ての特性が良好であることが判明した。   As is apparent from Table 3, it was found that all the characteristics of the production numbers 1 to 4 within the scope of the present invention were good.

これに対し、比較例の製造番号５〜２１の例では、いずれかの性能が劣っていた。   On the other hand, in the example of the manufacture numbers 5-21 of a comparative example, any performance was inferior.

具体的には、製造番号５の例では、Ｓｉ量が過剰のため、最終板の４５°方向の耳率が高く、印刷文字の曲がりを引き起こすことが判明した。また製造番号６の場合はＦｅ量が過剰のため、最終板の４５°方向の耳率が高く、印刷文字の曲がりを引き起こした。さらに製造番号７の場合は、Ｍｎ量が過剰のため、４５°耳が強く、印刷文字の曲がりが生じた。また製造番号８の場合は、Ｍｇ量が過少のため、強度が低くて耐圧強度が不足した。そしてまた製造番号９の場合は、Ｍｇ量が過剰のため、強度が高過ぎて、開栓時におけるブリッジが切れる際のトルク＃２が高過ぎて、開栓性に劣ることが判明した。   Specifically, in the example of the production number 5, since the amount of Si is excessive, the ear rate in the 45 ° direction of the final plate is high, and it has been found that the printed characters are bent. In the case of production number 6, since the amount of Fe was excessive, the ear rate in the 45 ° direction of the final plate was high, and the printed characters were bent. Further, in the case of production number 7, since the amount of Mn was excessive, the 45 ° ear was strong and the printed characters were bent. In the case of production number 8, since the amount of Mg was too small, the strength was low and the pressure strength was insufficient. Further, in the case of production number 9, since the amount of Mg was excessive, the strength was too high, and the torque # 2 when the bridge was broken at the time of opening was too high, and it was found that the opening performance was inferior.

一方、製造番号１０の場合は、熱間仕上げ圧延の最終パスの歪み速度が小さいため、熱間圧延後に再結晶していない部分が多く、そのため中間焼鈍時に立方体方位が過剰に発達して最終板の耳がマイナスとなり、０−１８０°位置で印刷文字の曲がりが生ずることが判明した。また製造番号１１の場合は、熱間仕上げ圧延終了温度が低いために熱間圧延後に再結晶していない部分が存在し、そのため中間焼鈍時に立方体方位が過剰に発達して、最終板の耳がマイナスとなり、０−１８０°位置で印刷文字の曲がりが生じることが判明した。さらに製造番号１２の場合は、熱間仕上げ圧延後の熱延板コイルの冷却速度が速く、そのため熱間圧延板に再結晶していない部分が存在し、これにより中間焼鈍時に立方体方位が過剰に発達して、最終板の耳がマイナスとなり、０−１８０°位置で印刷文字の曲がりが生じることが判明した。   On the other hand, in the case of the production number 10, since the strain rate of the final pass of the hot finish rolling is small, there are many parts that are not recrystallized after the hot rolling. It turned out that the ears of the prints were negative and the printed characters were bent at 0-180 °. In the case of production number 11, since the finish temperature of hot finish rolling is low, there is a portion that is not recrystallized after hot rolling, so that the cube orientation develops excessively during intermediate annealing, and the end of the final plate becomes It turned out to be negative, and it was found that the printed characters were bent at 0-180 ° position. Furthermore, in the case of serial number 12, the cooling rate of the hot-rolled sheet coil after hot finish rolling is high, and therefore there is a portion that is not recrystallized in the hot-rolled sheet, which causes excessive cube orientation during intermediate annealing. It has been found that the ear of the final plate becomes negative and the printed characters are bent at 0-180 °.

さらに製造番号１３の場合は、中間焼鈍前の１次冷延率Ｒ１が中間焼鈍後の最終冷延率Ｒ２と比較して大き過ぎるため、中間焼鈍時に発達した立方体方位に見合うだけの圧延集合組織が発達せず、そのため板の耳がマイナスとなり、０−１８０°位置で印刷文字の曲がりが生じることが判明した。また製造番号１４の場合は、中間焼鈍前の１次冷延率Ｒ１が中間焼鈍後の仕上冷延率Ｒ２と比較して低過ぎるため、中間焼鈍時に発達した立方体方位に比べて圧延集合組織が発達し過ぎ、そのため強い４５°耳となり、４５°位置で印刷文字の曲がりが生じることが判明した。そしてまた製造番号１５の場合は、仕上冷延率Ｒ２が低過ぎて、引張強さが低くなり、そのためキャップ天面の強度が充分ではなく、耐圧強度が不足することが判明した。そしてまた製造番号１６の場合は、仕上冷延率Ｒ２が高過ぎて引張強さが高くなり、開栓試験時のブリッジが切れるためのトルク＃２が高過ぎる問題が生じた。   Furthermore, in the case of production number 13, since the primary cold rolling rate R1 before the intermediate annealing is too large compared to the final cold rolling rate R2 after the intermediate annealing, the rolling texture is just enough to meet the cube orientation developed during the intermediate annealing. It has been found that the ears of the plate are negative and the printed characters are bent at 0-180 °. In the case of production number 14, since the primary cold rolling rate R1 before the intermediate annealing is too low compared to the finish cold rolling rate R2 after the intermediate annealing, the rolling texture is smaller than the cube orientation developed during the intermediate annealing. It has been found that it has developed too much, so it has a strong 45 ° ear and the printed characters bend at the 45 ° position. In the case of production number 15, it was found that the finish cold rolling rate R2 is too low and the tensile strength is low, so that the strength of the top surface of the cap is not sufficient and the pressure strength is insufficient. In the case of the production number 16, the finish cold rolling rate R2 is too high, the tensile strength is high, and there is a problem that the torque # 2 for breaking the bridge at the time of the opening test is too high.

一方、製造番号１７の場合は、中間焼鈍温度が低過ぎて中間焼鈍時に再結晶せず、そのため極度に強い４５°耳となり、印刷文字曲がりが発生し、さらには強度も高くなり過ぎ、ブリッジが切れる際の開栓トルク＃２値が大きくなってしまった。また製造番号１８の場合は、中間焼鈍温度が高過ぎて結晶粒径が粗大になったため、キャップ成形品表面に肌荒れが発生し、また中間焼鈍時に立方体方位が強くなって最終板の耳がマイナスになり、０−１８０°位置で印刷文字の曲がりが生じることが判明した。さらに製造番号１９の場合は、中間焼鈍の加熱保持時間が長過ぎて結晶粒径が粗大になったため、キャップ成形品表面に肌荒れが発生し、また中間焼鈍時に立方体方位が強くなって最終板の耳がマイナスになり、０−１８０°位置で印刷文字の曲がりが生じることが判明した。   On the other hand, in the case of the production number 17, the intermediate annealing temperature is too low and recrystallization does not occur during the intermediate annealing, so that it becomes an extremely strong 45 ° ear, the printed character is bent, the strength is too high, and the bridge is The opening torque # 2 value at the time of cutting became large. In the case of production number 18, since the intermediate annealing temperature was too high and the crystal grain size became coarse, the surface of the cap molded product was rough, and the cube orientation was strong during the intermediate annealing, and the final plate had a negative ear. It was found that the printed characters were bent at 0-180 °. Further, in the case of production number 19, since the heat retention time of the intermediate annealing is too long and the crystal grain size becomes coarse, the surface of the cap molded product is roughened, and the cube orientation becomes strong during the intermediate annealing, so that the final plate It was found that the ears became negative and the printed characters were bent at 0-180 °.

また製造番号２０の場合は、安定化処理温度が低過ぎて耐力／引張強さの比が高くなり過ぎ、そのため巻き締め時の天面のつぶし部分（絞り高さ）が浅くなって、耐圧強度が不足することが判明した。また製造番号２１の場合は、安定化処理温度が高過ぎて、耐力／引張強さの比が低くなり過ぎ、巻締め時のネジ部の深さが深くなり過ぎ、開栓時（キャップの回転開始時のトルク＃１）が高くなり過ぎることが判明した。   In the case of serial number 20, the stabilization temperature is too low and the ratio of proof stress / tensile strength becomes too high, so that the crushing portion (drawing height) of the top surface when tightening becomes shallow, and the pressure strength Was found to be lacking. In the case of serial number 21, the stabilization temperature is too high, the ratio of proof stress / tensile strength becomes too low, the thread depth when tightening becomes too deep, and when the cap is opened (cap rotation) It was found that the starting torque # 1) was too high.

Claims (1)

Ｍｇ１．５〜２．１％（ｍａｓｓ％、以下同じ）、Ｆｅ０．１〜０．４％、Ｓｉ０．０５〜０．３％、Ｍｎ０．１％以下（０％を含む）を含有し、残部がＡｌおよび不可避不純物からなるＡｌ合金の鋳塊に均質化処理を施した後、熱間粗圧延と熱間仕上げ圧延からなる熱間圧延を行なうにあたり、熱間仕上げ圧延における最終パスの歪み速度を９０ｓｅｃ ^-1 以上、熱間仕上圧延終了温度を３３０℃以上とし、得られた熱間圧延コイルを、２８０℃以上の温度域に３時間以上保持される冷却速度で冷却して、熱延板の再結晶率を９５％以上とし、次いで熱間圧延板に、圧延率Ｒ１の１次冷間圧延、中間焼鈍、圧延率Ｒ２の仕上冷間圧延をその順に施すにあたり、１次冷間圧延率Ｒ１と仕上冷間圧延率Ｒ２とが次式
１．３０×Ｒ２（％）≦Ｒ１（％）≦１．６０×Ｒ２（％）
を満たしかつ仕上冷間圧延率Ｒ２が４５〜５５％の範囲内となるように、１次冷間圧延と仕上冷間圧延を行なうとともに、その間の中間焼鈍を、到達温度４００〜５５０℃で２分以内保持の条件で行ない、仕上冷間圧延後、１７０〜２４０℃で０．５〜１２時間保持する安定化処理を施し、これによって、引張強さが１９０〜２５０ＭＰａであり、かつ耐力／引張強さの比が０．７５〜０．８５の範囲内にあり、しかも耳率が、４５°耳で２％以下であるキャップ用アルミニウム合金を得ることを特徴とする、開栓性、耳率に優れた高強度キャップ用アルミニウム合金板の製造方法。 Contains Mg 1.5-2.1% (mass%, the same shall apply hereinafter), Fe0.1-0.4%, Si 0.05-0.3%, Mn 0.1% or less (including 0%), the balance strain rate of the final pass but was subjected to homogenization treatment to an ingot of the Al alloy of Al and inevitable impurities ing, when performing hot rolling consisting of rough hot rolling and hot finish rolling, the finish hot rolling 90 sec ⁻¹ or more, the hot finish rolling end temperature is 330 ° C. or more, and the obtained hot rolled coil is cooled at a cooling rate that is maintained in a temperature range of 280 ° C. or more for 3 hours or more, When the recrystallization rate of the steel sheet is 95% or higher, and then the hot cold rolled sheet is subjected to primary cold rolling at a rolling rate R1, intermediate annealing, and finish cold rolling at a rolling rate R2 in that order, the primary cold rolling rate R1 and finish cold rolling rate R2 are the following formulas
1.30 × R2 (%) ≦ R1 (%) ≦ 1.60 × R2 (%)
Are satisfied, and the finish cold rolling rate R2 is in the range of 45 to 55%, and the primary cold rolling and the finish cold rolling are performed, and the intermediate annealing is performed at an ultimate temperature of 400 to 550 ° C. It is carried out under the condition of holding within minutes, and after the finish cold rolling, it is subjected to a stabilizing treatment of holding at 170-240 ° C. for 0.5-12 hours, whereby the tensile strength is 190-250 MPa and the proof stress / tensile Opening property, ear rate characterized by obtaining an aluminum alloy for caps having a strength ratio in the range of 0.75 to 0.85 and an ear rate of 2% or less at 45 ° ears For producing high-strength aluminum alloy sheets for caps.