JP5818457B2 - Method for producing aluminum alloy plate for can body with low ear rate and method for producing aluminum alloy plate for bottle-type beverage can with low ear rate - Google Patents

Description

本発明は、耳率が低い缶ボディ用アルミニウム合金板の製造方法および耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法に関する。   The present invention relates to a method for producing an aluminum alloy plate for a can body having a low ear rate and a method for producing an aluminum alloy plate for a bottle-type beverage can having a low ear rate.

一般に缶ボディとしては、その開口端部に缶蓋が巻締められる缶や、開口端部にキャップが螺着されるボトル缶等があり、飲料等の内容物が充填、密封され、市場において流通している。このような缶ボディは、従来、ＪＩＳ３００４（ＡＡ３００４）またはＪＩＳ３１０４（ＡＡ３１０４）のＡｌ合金からなる板材に絞り加工およびしごき加工を施すことによって行われるＤＩ（Deep Draw & Ironing）加工により形成されている。  In general, the can body includes a can with a can lid wound around its open end and a bottle can with a cap screwed into its open end, filled with beverages and other contents, and distributed in the market. doing. Such a can body is conventionally formed by DI (Deep Draw & Ironing) processing performed by drawing and ironing a plate material made of an Al alloy of JIS3004 (AA3004) or JIS3104 (AA3104).

また、缶入り飲料水などの需要増加に伴ってアルミニウム合金製のボトル型の飲料缶が開発されてきている。ボトル型の飲料缶は図４に示すように、底部１６を有する円筒状の胴部１１の上部に、直径が減少する肩部１２を介して頸部１３が形成されている。頸部１３にはキャップ（図示省略）をねじ込むためのネジ部１４が形成されており、ネジ部１４の先端には口当たりを良くするためのカール部１５が形成されている。   Further, along with an increase in demand for canned drinking water, bottle-shaped beverage cans made of aluminum alloy have been developed. As shown in FIG. 4, the bottle-shaped beverage can has a neck portion 13 formed on the upper portion of a cylindrical body portion 11 having a bottom portion 16 via a shoulder portion 12 having a reduced diameter. A screw portion 14 for screwing a cap (not shown) is formed on the neck portion 13, and a curl portion 15 for improving mouth feel is formed at the tip of the screw portion 14.

図４に示すようなボトル型飲料缶１０の製造方法の概要を示せば図５の通りとなる。すなわち、例えばＪＩＳ３００４合金のようなＡｌ−Ｍｎ−Ｍｇ系合金のブランク材１に深絞り加工を施し、カップ２を形成する。
次いでカップ２にしごき加工を施して缶体３を形成する。深絞り、しごき成形した時には板材の圧延方向に応じて、成形した缶体の上縁の高さが山谷状に変化する現象が起こる。この山谷状に変化した部分３Ａは通常「耳」と呼ばれている。
次いで、深絞り、しごき加工を行った缶体３は耳３Ａの部分を切断するトリム加工を行って缶の高さを揃える。トリム加工の際に除去される耳の部分の板材の割合が多いと、材料歩留まりが低下し製造コストが上昇する。従って除去すべき板材の割合（以下、「耳率」と呼ぶ）は低いことが望まれる。 If the outline | summary of the manufacturing method of the bottle-type drink can 10 as shown in FIG. 4 is shown, it will become as FIG. That is, the cup 2 is formed by deep drawing the blank material 1 made of an Al—Mn—Mg alloy such as JIS 3004 alloy.
Next, the can 2 is formed by ironing the cup 2. When deep drawing or ironing is formed, a phenomenon occurs in which the height of the upper edge of the formed can body changes in a mountain-valley shape depending on the rolling direction of the plate material. The portion 3A that changes in the shape of a valley is usually called an “ear”.
Next, the can body 3 that has been deep-drawn and ironed is trimmed to cut the portion of the ear 3A so that the height of the can is made uniform. When the ratio of the plate material of the ear portion removed at the time of trimming is large, the material yield decreases and the manufacturing cost increases. Therefore, it is desirable that the ratio of the plate material to be removed (hereinafter referred to as “ear ratio”) is low.

耳を除去した缶体３は、縮径加工を施して肩部１２と頸部１３を形成し、その先端部を形成しようとするネジの谷径と同程度の径の円筒状に絞り成形し、さらに残った部位をロールフォーミングなどによって凹凸変形させてネジ部１４を形成し、最後に先端部をロールで丸くカール加工してボトル型飲料缶１０とする。   The can 3 from which the ears have been removed is subjected to diameter reduction processing to form a shoulder 12 and a neck 13, and is drawn into a cylindrical shape having a diameter similar to the diameter of the valley of the screw to be formed at the tip. Further, the remaining part is deformed by roll forming or the like to form a screw part 14, and finally the tip part is rounded with a roll to form a bottle-type beverage can 10.

このようにボトル型飲料缶においては、従来のアルミニウム缶の主流であったＤＩ缶（Deep drawing & Ironing 缶）に比較して頸部に一段と厳しい塑性加工を施すため、素材にも一段と高い特性が要求される。   In this way, the bottle-type beverage can has a much higher characteristic in the material because the neck is subjected to severer plastic working than the DI can (Deep drawing & Ironing can), which was the mainstream of conventional aluminum cans. Required.

従来の飲料缶用のアルミニウム合金板材の製造方法としては種々の方法が提案されており、例えばスラブに造塊後均質化処理を行い、熱間圧延後、中間焼鈍を施すことなく冷間圧延する方法が知られている（例えば、特許文献１参照）。ところが、ボトル型アルミニウム飲料缶の場合、頸部にネッキング加工やネジ加工を施すため、従来の板材の製造方法ではネッキング加工やネジ加工で加工軟化を起こし、頸部の強度が低下する欠点がある。   Various methods have been proposed for producing conventional aluminum alloy sheets for beverage cans. For example, slabs are subjected to homogenization after ingot forming, and after hot rolling, cold rolling is performed without intermediate annealing. A method is known (see, for example, Patent Document 1). However, in the case of a bottle-type aluminum beverage can, necking and screwing are performed on the neck, so the conventional plate manufacturing method has the disadvantage that the necking and screwing cause processing softening and the neck strength is reduced. .

そこで、本出願人は、ネッキング加工やネジ加工で加工硬化を起こし、特に頸部の強度が高いボトル型飲料用アルミニウム缶の製造に適したアルミニウム合金板の製造方法について、先に特許出願している（特許文献２参照）。この特許出願に係る技術では、アルミニウム合金の鋳塊に熱間圧延、圧下率６０〜９５％の第１冷間圧延、保持温度３３０〜４００℃かつ保持時間１〜３０秒の第１段中間焼鈍、圧下率５〜４０％の第２冷間圧延、保持温度５００〜５６０℃かつ保持時間１〜３０秒の第２中間焼鈍、圧下率４５〜６９％の最終冷間圧延を順次施すことが要件とされていた。   Therefore, the applicant has previously filed a patent application for a method of manufacturing an aluminum alloy plate suitable for manufacturing a bottle-type beverage aluminum can that is hardened by necking or screw processing and has particularly high neck strength. (See Patent Document 2). In the technology according to this patent application, hot rolling to an ingot of an aluminum alloy, first cold rolling with a rolling reduction of 60 to 95%, first stage intermediate annealing with a holding temperature of 330 to 400 ° C. and a holding time of 1 to 30 seconds. The second cold rolling at a rolling reduction of 5 to 40%, the second intermediate annealing at a holding temperature of 500 to 560 ° C. and a holding time of 1 to 30 seconds, and the final cold rolling at a rolling reduction of 45 to 69% are sequentially required. It was said.

特開昭５９−１６２２６１号公報JP 59-162261 A 特許第３８６８８３９号公報Japanese Patent No. 386839

特許文献２の技術によれば、ネッキング加工やネジ加工で加工硬化を起こし、特に頸部の強度が高いボトル型飲料用アルミニウム缶に適したアルミニウム合金板を製造できる。しかし、特許文献２の製造方法は、前述の如く熱間圧延後の冷間圧延の圧下率が６０〜９５％と高いため、冷間圧延のパス回数を多く要し、生産性の面で改良が望まれる。   According to the technique of Patent Document 2, it is possible to produce an aluminum alloy plate suitable for a bottle-type beverage aluminum can that is hardened by necking or screwing and particularly has a high neck strength. However, the manufacturing method of Patent Document 2 has a high rolling reduction ratio of 60 to 95% after hot rolling as described above, and thus requires a large number of cold rolling passes and is improved in terms of productivity. Is desired.

そこで、本発明者らは、熱間圧延後の第１冷間圧延の圧下率を低下させて生産性を向上するべく、熱間圧延工程において、シングルミルのリバース式熱間仕上げ圧延機を用いることにより、熱間圧延後のアルミニウム合金板厚を５ｍｍ以下程度に薄くする検討を行った。しかしながら、本発明者らの知見によれば、熱間圧延の仕上り板厚が薄くなり、第１冷間圧延率が低下すると、第１中間焼鈍時の歪導入量が不足して、第２中間焼鈍後に圧延方向に対して０°および９０°方向の耳（以下０−９０°耳）が発達しにくくなり、結果的に低耳率の最終冷間圧延板材を得るのが難しいという問題があった。熱間圧延後の板厚が５ｍｍを超える場合には、第１中間焼鈍時の歪導入量が十分であるため耳率への影響が少ないが、熱間圧延後の板厚が厚くなると、冷間圧延のパス回数が増加して生産性が低下する。   Therefore, the present inventors use a single-mill reverse hot finish rolling mill in the hot rolling process in order to improve the productivity by reducing the reduction ratio of the first cold rolling after hot rolling. Thus, studies were made to reduce the thickness of the aluminum alloy sheet after hot rolling to about 5 mm or less. However, according to the knowledge of the present inventors, when the finished thickness of the hot rolling is reduced and the first cold rolling rate is reduced, the strain introduction amount at the first intermediate annealing is insufficient, and the second intermediate After annealing, the ears in the 0 ° and 90 ° directions with respect to the rolling direction (hereinafter referred to as 0-90 ° ears) are difficult to develop, and as a result, it is difficult to obtain a final cold-rolled sheet with a low earing rate. It was. If the plate thickness after hot rolling exceeds 5 mm, the amount of strain introduced during the first intermediate annealing is sufficient, so there is little effect on the ear rate, but if the plate thickness after hot rolling becomes thick, The number of passes during hot rolling increases and productivity decreases.

本発明はこのような事情に鑑みてなされたものであり、耳率が低い缶ボディ用アルミニウム合金板の製造方法を提供することを目的とする。また、本発明は、耳率が低く、胴部、肩部の強度を満足し、ネッキング加工やネジ加工で加工硬化を起こし、特に頸部の強度が高いボトル型飲料用アルミニウム缶を製造するのに適したアルミニウム合金板の製造方法を提供することを目的とする。   This invention is made | formed in view of such a situation, and it aims at providing the manufacturing method of the aluminum alloy plate for can bodies with a low ear rate. In addition, the present invention produces an aluminum can for bottle-type beverages that has a low ear rate, satisfies the strength of the body and shoulders, undergoes work hardening by necking and screw processing, and particularly has a high neck strength. An object of the present invention is to provide a method for producing an aluminum alloy plate suitable for the above.

本発明者らは、熱間圧延の仕上り板厚と仕上り温度を厳密に制御することにより、熱間圧延後の板厚を５ｍｍ以下と薄くした場合でも、熱間圧延後の再結晶率を制御することで、第２中間焼鈍後に０−９０°耳を発達させ、製造される缶材の耳率を低くできることを見出し、本発明に至った。すなわち、本発明は以下の構成を採用した。
上記課題を解決するため、本発明の耳率が低い缶ボディ用アルミニウム合金板の製造方法は、質量％で、Ｓｉ：０．２〜０．４５％、Ｆｅ：０．３〜０．５５％、Ｃｕ：０．１５〜０．４％、Ｍｎ：０．８〜１．２％、Ｍｇ：０．５〜１．７％、Ｃｒ：０．００１〜０．０５％、Ｚｎ：０．０５〜０．４％、Ｔｉ：０．００１〜０．１％を含有し、残部が不可避的不純物を含むＡｌからなる組成のアルミニウム合金を溶製し、半連続鋳造して得た鋳塊を５６０〜６１０℃で均質化処理し、その後熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、該熱間仕上げ圧延の最終パスを歪速度が１０〜１５０／秒の条件下で仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御し、熱間仕上げ圧延後の耐力を１０８〜１６３ＭＰａの範囲にするとともに、続いて圧下率を２０〜７５％とする第１冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度３３０〜４００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第１中間焼鈍を行ない、続いて圧下率１０〜２０％で第２冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度５００〜６００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第２中間焼鈍を行ない、さらに圧下率６０〜７１％の条件で最終板厚まで最終冷間圧延を行うことを特徴とする。
本発明において、前記熱間仕上げ圧延の仕上り板厚ｘ（ｍｍ）を２．０≦ｘ≦４．５、前記第１冷間圧延の圧下率を４５〜７０％とすることにより、耳率１．４〜２．３％のアルミニウム合金板を得ることができる。 The present inventors control the recrystallization rate after hot rolling even when the thickness after hot rolling is reduced to 5 mm or less by strictly controlling the finished thickness and temperature of hot rolling. As a result, 0-90 ° ears were developed after the second intermediate annealing, and the ear rate of the manufactured can material was found to be low, and the present invention was achieved. That is, the present invention employs the following configuration.
In order to solve the above-mentioned problems, the method for producing an aluminum alloy plate for a can body having a low ear rate according to the present invention is in mass%, Si: 0.2 to 0.45%, Fe: 0.3 to 0.55%. Cu: 0.15-0.4%, Mn: 0.8-1.2%, Mg: 0.5-1.7%, Cr: 0.001-0.05%, Zn: 0.05 An ingot obtained by melting a semi-continuous cast aluminum alloy containing ˜0.4%, Ti: 0.001 to 0.1%, and the balance of Al containing inevitable impurities is 560 Homogenizing at ˜610 ° C., followed by hot rolling by hot rough rolling and subsequent hot finish rolling, and finishing the final pass of the hot finish rolling under conditions of strain rate of 10 to 150 / sec. The relationship between the temperature y (° C.) and the finished plate thickness x (mm) is 240 ≦ y ≦ 20x + 240 (where 2.0 ≦ x ≦ 5. ), The yield strength after hot finish rolling is in the range of 108 to 163 MPa, and after performing the first cold rolling with a reduction rate of 20 to 75%, a continuous annealing apparatus is used. The first intermediate annealing is performed under the conditions of a heating rate of 10 to 200 ° C./second, a holding temperature of 330 to 400 ° C., a holding time of 0 to 30 seconds, and a cooling rate of 10 to 200 ° C./second, followed by a reduction rate of 10 to 20 After performing the second cold rolling at%, the heating rate is 10 to 200 ° C./second, the holding temperature is 500 to 600 ° C., the holding time is 0 to 30 seconds, and the cooling rate is 10 to 200 ° C./second using a continuous annealing apparatus. The second intermediate annealing is performed under the conditions, and the final cold rolling is performed to the final plate thickness under the conditions of a rolling reduction of 60 to 71%.
In the present invention, the finished sheet thickness x (mm) of the hot finish rolling is 2.0 ≦ x ≦ 4.5, and the reduction ratio of the first cold rolling is 45 to 70%. .4 to 2.3% aluminum alloy sheet can be obtained.

上記課題を解決するため、本発明の耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法は、絞り加工としごき加工とネッキング加工とネジ加工が施されて底部と胴部と肩部と頸部とが一体成形され前記頸部にネジ部が形成されてなるボトル型飲料缶を形成するための素材となるアルミニウム合金板の製造方法であり、質量％で、Ｓｉ：０．２〜０．４５％、Ｆｅ：０．３〜０．５５％、Ｃｕ：０．１５〜０．４％、Ｍｎ：０．８〜１．２％、Ｍｇ：０．５〜１．７％、Ｃｒ：０．００１〜０．０５％、Ｚｎ：０．０５〜０．４％、Ｔｉ：０．００１〜０．１％を含有し、残部が不可避的不純物を含むＡｌからなる組成のアルミニウム合金を溶製し、半連続鋳造して得た鋳塊を５６０〜６１０℃で均質化処理し、その後熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、該熱間仕上げ圧延の最終パスを歪速度が１０〜１５０／秒の条件下で仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御し、熱間仕上げ圧延後の耐力を１０８〜１６３ＭＰａの範囲にするとともに、続いて圧下率を２０〜７５％とする第１冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度３３０〜４００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第１中間焼鈍を行ない、続いて圧下率１０〜２０％で第２冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度５００〜６００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第２中間焼鈍を行ない、さらに圧下率６０〜６９％の条件で最終板厚まで最終冷間圧延を行う、前記ネッキング加工時に頸部耐力の増加をもたらす特徴を有する。
本発明において、前記熱間仕上げ圧延の仕上り板厚ｘ（ｍｍ）を２．０≦ｘ≦４．５、前記第１冷間圧延の圧下率を４５〜７０％とすることにより、耳率１．４〜２．３％、ネッキング後に３〜９ＭＰａ耐力が向上するアルミニウム合金板を得ることができる。 In order to solve the above problems, the method for producing an aluminum alloy plate for a bottle-type beverage can according to the present invention includes a drawing process, ironing process, necking process, screw process, and a bottom part, a body part, and a shoulder part. A method for producing an aluminum alloy plate as a material for forming a bottle-type beverage can formed integrally with a neck and having a threaded portion formed on the neck, wherein Si: 0.2-0 .45%, Fe: 0.3 to 0.55%, Cu: 0.15 to 0.4%, Mn: 0.8 to 1.2%, Mg: 0.5 to 1.7%, Cr: An aluminum alloy containing 0.001 to 0.05%, Zn: 0.05 to 0.4%, Ti: 0.001 to 0.1%, and the balance of Al containing inevitable impurities is dissolved. The ingot obtained by semi-continuous casting is homogenized at 560 to 610 ° C., and then hot rough rolling and Subsequent hot rolling by hot finish rolling is performed, and the relationship between the finishing temperature y (° C.) and the finished sheet thickness x (mm) in the final pass of the hot finishing rolling is performed under the condition that the strain rate is 10 to 150 / sec. Is controlled so as to satisfy 240 ≦ y ≦ 20x + 240 (where 2.0 ≦ x ≦ 5.0), the yield strength after hot finish rolling is in the range of 108 to 163 MPa, and subsequently the rolling reduction is 20 to After performing the first cold rolling to 75%, using a continuous annealing apparatus, a heating rate of 10 to 200 ° C / second, a holding temperature of 330 to 400 ° C, a holding time of 0 to 30 seconds, a cooling rate of 10 to 200 ° C / second After performing the first intermediate annealing under the conditions of seconds, and subsequently performing the second cold rolling at a reduction rate of 10 to 20%, the heating rate is 10 to 200 ° C./second and the holding temperature is 500 to 600 using a continuous annealing apparatus. ° C, holding time 0-30 seconds, cooling rate 10 00 ° C. / sec becomes performs second intermediate annealing under the conditions, further performing final cold rolling to a final thickness at a reduction ratio from 60 to 69% of conditions, having the characteristics results in increased neck strength during the necking.
In the present invention, the finished sheet thickness x (mm) of the hot finish rolling is 2.0 ≦ x ≦ 4.5, and the reduction ratio of the first cold rolling is 45 to 70%. It is possible to obtain an aluminum alloy plate having a yield resistance of 3 to 9 MPa after necking of 0.4 to 2.3%.

本発明の缶ボディ用アルミニウム合金板の製造方法は、アルミニウム合金鋳塊に均質化処理と熱間圧延と第１冷間圧延と第１中間焼鈍と第２冷間圧延と第２中間焼鈍と最終冷間圧延とを順次施してアルミニウム合金板を製造するに際し、特に、熱間仕上げ圧延の最終パスを仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御して行うことにより、熱間圧延後の再結晶率を低く抑えることができるので、以降の第１冷間圧延の圧下率を２０〜７５％と常法よりも低くすることができる。従って、本発明の缶ボディ用アルミニウム合金板の製造方法によれば、熱間圧延後の再結晶率が低いため、第２中間焼鈍後に０−９０°耳を発達させることができるので、缶ボディに加工する際に耳率が低いアルミニウム合金板を製造できる。また、第１冷間圧延率を前記の如く低くできるので、冷間圧延のパス回数を削減することができ、生産性を向上できる。   The method for producing an aluminum alloy plate for a can body according to the present invention comprises: homogenization treatment, hot rolling, first cold rolling, first intermediate annealing, second cold rolling, second intermediate annealing, and final processing on an aluminum alloy ingot. When producing an aluminum alloy sheet by sequentially performing cold rolling, the relationship between the finished temperature y (° C.) and the finished sheet thickness x (mm) is 240 ≦ y ≦ 20x + 240 (provided that the final pass of the hot finish rolling is in particular) , 2.0 ≦ x ≦ 5.0), the recrystallization rate after hot rolling can be kept low, so that the subsequent first cold rolling reduction rate is 20 It can be made lower than the conventional method by ˜75%. Therefore, according to the method for producing an aluminum alloy plate for a can body of the present invention, since the recrystallization rate after hot rolling is low, a 0-90 ° ear can be developed after the second intermediate annealing. An aluminum alloy plate having a low ear rate can be produced when processing into a sheet. In addition, since the first cold rolling rate can be lowered as described above, the number of cold rolling passes can be reduced, and productivity can be improved.

本発明のボトル型飲料缶用アルミニウム合金板の製造方法は、アルミニウム合金鋳塊に均質化処理と熱間圧延と第１冷間圧延と第１中間焼鈍と第２冷間圧延と第２中間焼鈍と最終冷間圧延とを順次施してアルミニウム合金板を製造するに際し、特に、熱間仕上げ圧延の最終パスを仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御して行うことにより、熱間圧延後の再結晶率を低く抑えることができるので、以降の第１冷間圧延の圧下率を２０〜７５％と常法よりも低くすることができる。従って、ボトル型飲料缶用アルミニウム合金板の製造方法によれば、熱間圧延後の再結晶率が低いため、第２中間焼鈍後に０−９０°耳を発達させることができるので、缶体に加工する際に耳率が低いアルミニウム合金板を製造できる。また、第１冷間圧延率を前記の如く低くできるので、冷間圧延のパス回数を削減することができ、生産性を向上できる。
さらに、ボトル型飲料缶用アルミニウム合金板の製造方法は、最終冷間圧延の圧下率を所定範囲に規定することにより、ボトル型飲料缶に加工するに際し、耳率が低く、胴部、肩部の強度を満足し、ネッキング加工やネジ加工で加工硬化を起こすので、特に頸部の強度が高いボトル型飲料缶用アルミニウム缶を製造するのに適したアルミニウム合金板を製造できる。 The method for producing an aluminum alloy plate for a bottle-type beverage can according to the present invention comprises homogenizing, hot rolling, first cold rolling, first intermediate annealing, second cold rolling, and second intermediate annealing on an aluminum alloy ingot. And the final cold rolling are sequentially performed to produce an aluminum alloy sheet. In particular, the relationship between the finishing temperature y (° C.) and the finished sheet thickness x (mm) is 240 ≦ y ≦ 20x + 240 in the final pass of the hot finish rolling. (However, by performing control so as to satisfy 2.0 ≦ x ≦ 5.0), the recrystallization rate after hot rolling can be kept low, so that the reduction rate of the subsequent first cold rolling Can be made 20-75% lower than a conventional method. Therefore, according to the manufacturing method of the aluminum alloy plate for bottle-type beverage cans, since the recrystallization rate after hot rolling is low, the 0-90 ° ear can be developed after the second intermediate annealing, so that the can body When processing, an aluminum alloy plate having a low ear rate can be manufactured. In addition, since the first cold rolling rate can be lowered as described above, the number of cold rolling passes can be reduced, and productivity can be improved.
Furthermore, the manufacturing method of the aluminum alloy plate for bottle-type beverage cans has a low ear rate, a body portion, a shoulder portion when processing into a bottle-type beverage can by defining the rolling reduction ratio of the final cold rolling within a predetermined range. Therefore, the aluminum alloy plate suitable for producing an aluminum can for a bottle-type beverage can having a particularly high neck strength can be produced.

図１は本発明に係る製造方法を実施する際に、熱間圧延工程において用いる装置と工程を示す説明図。FIG. 1 is an explanatory view showing an apparatus and a process used in a hot rolling process when a manufacturing method according to the present invention is carried out. 本発明に係る製造方法の熱間圧延工程における、仕上り板厚と仕上り温度の関係を示すグラフ。The graph which shows the relationship between finishing board thickness and finishing temperature in the hot rolling process of the manufacturing method which concerns on this invention. 本発明に係る製造方法の実施に用いる連続焼鈍装置の一例を示す概略構成図。The schematic block diagram which shows an example of the continuous annealing apparatus used for implementation of the manufacturing method which concerns on this invention. ボトル型飲料缶の一例構造を示す断面図。Sectional drawing which shows an example structure of a bottle-type drink can. 図４に示すボトル型飲料缶の概略工程を示す図。The figure which shows the schematic process of the bottle-type drink can shown in FIG.

以下、本発明に係る耳率が低い缶ボディ用アルミニウム合金板の製造方法、及び、耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法の実施の形態について説明するが、初めに、本発明に係る缶ボディ用アルミニウム合金板の製造方法及びボトル型飲料缶用アルミニウム合金板の製造方法に用いるアルミニウム合金組成について説明する。   Hereinafter, embodiments of a method for producing an aluminum alloy plate for a can body having a low ear rate and a method for producing an aluminum alloy plate for a bottle-type beverage can having a low ear rate according to the present invention will be described. The aluminum alloy composition used for the manufacturing method of the aluminum alloy plate for can bodies which concerns on invention, and the manufacturing method of the aluminum alloy plate for bottle type drink cans is demonstrated.

本実施形態の缶ボディ用アルミニウム合金板及びボトル型飲料缶用アルミニウム合金板は、質量％で、Ｓｉ：０．２〜０．４５％、Ｆｅ：０．３〜０．５５％、Ｃｕ：０．１５〜０．４％、Ｍｎ：０．８〜１．２％、Ｍｇ：０．５〜１．７％、Ｃｒ：０．００１〜０．０５％、Ｚｎ：０．０５〜０．４％、Ｔｉ：０．００１〜０．１％を含有し、残部が不可避的不純物を含むＡｌからなる組成のアルミニウム合金からなる。以下、本発明で使用するアルミニウム合金の組成限定理由について説明する。
なお、本明細書において記載する各元素の含有量は、特に限定しない限り質量％であり、また、特に規定しない限り上限と下限を含むものとする。例えば０．２〜０．４５％との表記は０．２％以上０．４５％以下を意味する。
また、先のアルミニウム合金の基本的な組成自体は特殊なものではなく、現在大量に用いられている種々のアルミニウム缶用合金の組成の範囲内のものであるから、本発明の製造方法はリサイクルされたアルミニウム缶を原料として経済的にかつ効率よく本発明のアルミニウム合金板を製造するのに適している。 The aluminum alloy plate for can bodies and the aluminum alloy plate for bottle-type beverage cans of this embodiment are in mass%, Si: 0.2 to 0.45%, Fe: 0.3 to 0.55%, Cu: 0. .15-0.4%, Mn: 0.8-1.2%, Mg: 0.5-1.7%, Cr: 0.001-0.05%, Zn: 0.05-0.4 %, Ti: 0.001 to 0.1%, and the balance is made of an aluminum alloy having a composition made of Al containing inevitable impurities. Hereinafter, the reasons for limiting the composition of the aluminum alloy used in the present invention will be described.
In addition, content of each element described in this specification is mass% unless otherwise specified, and includes an upper limit and a lower limit unless otherwise specified. For example, the notation of 0.2 to 0.45% means 0.2% or more and 0.45% or less.
In addition, the basic composition of the aluminum alloy is not special, and is within the range of various aluminum can alloys currently used in large quantities. It is suitable for producing the aluminum alloy plate of the present invention economically and efficiently using the prepared aluminum can as a raw material.

「Ｓｉ：０．２〜０．４５％」
Ｓｉは、同時に含有するＭｇと化合物を形成し易く、固溶硬化作用、分散硬化作用および析出硬化作用を有する他、Ａｌ、Ｍｎ、Ｆｅなどと化合物を形成し、しごき成形時のダイスに対する焼付きを防止する効果がある。Ｓｉの含有量は、０.２質量％未満では所望の潤滑特性を確保することができず、また０.４５質量％を越えると加工性が劣化して不都合である。 "Si: 0.2-0.45%"
Si easily forms a compound with Mg contained at the same time, and has a solid solution hardening action, a dispersion hardening action and a precipitation hardening action, and forms a compound with Al, Mn, Fe, etc., and seizures on the die during ironing molding There is an effect to prevent. If the Si content is less than 0.2% by mass, desired lubrication properties cannot be ensured, and if it exceeds 0.45% by mass, the workability deteriorates, which is inconvenient.

「Ｆｅ：０．３〜０．５５％」
Ｆｅは、結晶の微細化およびしごき成形時のダイスに対する焼付きを防止する効果がある。Ｆｅの含有量は、０.３質量％未満では所望の効果が得られず、０.５５質量％を越えると加工性を劣化させる。
「Ｃｕ：０．１５〜０．４％」
Ｃｕは、Ｍｇと化合物を形成し易く、固溶硬化、分散硬化および析出硬化に寄与する。Ｃｕの含有量は、０.１５質量％未満では所望の効果が得られず、０.４質量％を越えると加工性を劣化させる。 "Fe: 0.3-0.55%"
Fe has the effect of preventing crystal seizure and seizure to a die during ironing. If the Fe content is less than 0.3% by mass, the desired effect cannot be obtained, and if it exceeds 0.55% by mass, the workability deteriorates.
"Cu: 0.15-0.4%"
Cu easily forms a compound with Mg, and contributes to solid solution hardening, dispersion hardening, and precipitation hardening. If the Cu content is less than 0.15% by mass, the desired effect cannot be obtained, and if it exceeds 0.4% by mass, the workability deteriorates.

「Ｍｎ：０．８〜１．２％」
Ｍｎは、Ｆｅ、Ｓｉ、Ａｌなどと化合物を形成し易く、晶出相および分散相となって分散硬化作用を現すと共にしごき成形時のダイスに対する焼付きを防止する効果がある。Ｍｎの含有量は、０.８質量％未満では所望の硬化特性が得られず、１.２質量％を越えると加工性が劣化する。
「Ｍｇ：０．５〜１．７％」
Ｍｇは、固溶体強化作用を有し、圧延による加工硬化性を高めるとともに、前記Ｓｉや前記Ｃｕと共存することによって分散硬化と析出硬化作用を現す。Ｍｇの含有量は、０.５質量％未満では所望の効果が得られず、１.７質量％を越えると加工性を劣化させるようになる。 "Mn: 0.8-1.2%"
Mn is easy to form a compound with Fe, Si, Al, etc., becomes a crystallization phase and a dispersed phase, exhibits a dispersion hardening action, and has an effect of preventing seizure to a die during ironing. If the Mn content is less than 0.8% by mass, desired curing characteristics cannot be obtained, and if it exceeds 1.2% by mass, the workability deteriorates.
“Mg: 0.5-1.7%”
Mg has a solid solution strengthening action, enhances work hardening by rolling, and exhibits dispersion hardening and precipitation hardening action by coexisting with Si and Cu. If the Mg content is less than 0.5% by mass, the desired effect cannot be obtained, and if it exceeds 1.7% by mass, the workability deteriorates.

「Ｃｒ：０．００１〜０．０５％」
Ｃｒは結晶の微細化としごき成形加工時にダイスに対する焼き付きを防止する効果を発揮する。Ｃｒの含有量は、０．００１質量％未満では所望の効果が得られず、０．０５質量％を越えると脆くなり加工性が劣化する。
「Ｚｎ：０．０５〜０．４％」
ＺｎはＭｇ、Ｓｉ、Ｃｕの析出物を微細化する作用を有する。Ｚｎの含有量は、０.０５質量％未満では所望の効果が得られず、０.４質量％を越えると加工性と耐食性を劣化させる。 “Cr: 0.001 to 0.05%”
Cr exerts the effect of preventing the seizure of the die during the squeezing process by making the crystal finer. If the content of Cr is less than 0.001% by mass, the desired effect cannot be obtained, and if it exceeds 0.05% by mass, it becomes brittle and the workability deteriorates.
“Zn: 0.05 to 0.4%”
Zn has the effect of refining Mg, Si and Cu precipitates. If the Zn content is less than 0.05% by mass, the desired effect cannot be obtained, and if it exceeds 0.4% by mass, the workability and corrosion resistance are deteriorated.

「Ｔｉ：０．００１〜０．１％」
Ｔｉは、結晶粒を微細化して加工性を改善する効果がある。ただし、Ｔｉの含有量は０.１質量％を越えると粗大な化合物を生成し、逆に加工性を劣化させ、０.００１質量％未満では効果がほとんど得られない。 “Ti: 0.001 to 0.1%”
Ti has the effect of improving the workability by refining crystal grains. However, if the Ti content exceeds 0.1% by mass, a coarse compound is produced, and conversely, the workability deteriorates. If the Ti content is less than 0.001% by mass, almost no effect is obtained.

＜耳率が低い缶ボディ用アルミニウム合金板の製造方法＞
次に、本発明に係る耳率が低い缶ボディ用アルミニウム合金板の製造方法の実施の形態について説明する。
本実施形態の耳率が低い缶ボディ用アルミニウム合金板の製造方法においては、前記組成のアルミニウム合金を溶製し、鋳造して得た鋳塊に対して均質化処理した後、熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、続いて第１冷間圧延、第１中間焼鈍、第２冷間圧延、第２中間焼鈍を順次施して、さらに最終冷間圧延を行うことにより所望の板厚の缶ボディ用アルミニウム合金板を得る。以下、本実施形態の耳率が低い缶ボディ用アルミニウム合金板の製造方法について順を追って説明する。 <Method of manufacturing aluminum alloy plate for can body with low ear rate>
Next, an embodiment of a method for producing a can body aluminum alloy plate having a low ear rate according to the present invention will be described.
In the method for producing an aluminum alloy sheet for can bodies having a low ear rate according to the present embodiment, hot rough rolling is performed after melting the aluminum alloy having the above composition and homogenizing the ingot obtained by casting. And subsequent hot rolling by hot finish rolling, followed by the first cold rolling, the first intermediate annealing, the second cold rolling, the second intermediate annealing, and the final cold rolling. Thus, an aluminum alloy plate for a can body having a desired plate thickness is obtained. Hereinafter, the manufacturing method of the aluminum alloy plate for can bodies having a low ear rate according to this embodiment will be described in order.

「鋳造」
前記組成のアルミニウム合金を溶解後、常法に従ってアルミニウム合金溶湯から鋳塊を鋳造するが、鋳造に先立ち、アルミニウム合金を溶製した際に、水素ガスや酸化物などの介在物を除去し、半連続鋳造法により鋳塊を得る。
このときの凝固速度は通常、５〜２０℃／秒とされる。鋳造された鋳塊の厚さは、例えば５００〜６００ｍｍ程度とすることができる。
次に、面削を行い、鋳塊の表面を１〜２５ｍｍ程度研磨して、表面が平滑化された面削体を作製する。 "casting"
After the aluminum alloy having the above composition is melted, an ingot is cast from the molten aluminum alloy according to a conventional method. When the aluminum alloy is melted prior to casting, inclusions such as hydrogen gas and oxide are removed, An ingot is obtained by a continuous casting method.
The solidification rate at this time is usually 5 to 20 ° C./second. The thickness of the cast ingot can be about 500 to 600 mm, for example.
Next, chamfering is performed, and the surface of the ingot is polished by about 1 to 25 mm to produce a chamfered body having a smooth surface.

「均質化処理」
次に、作製した面削体に均質化処理を施す。均質化処理は一般に、溶湯の凝固によって生じたミクロ偏析の均質化、過飽和固溶元素の析出、凝固によって形成された準安定相の平衡相への転移などのために行われる。
均質化処理においては、均質化温度を５６０〜６１０℃の範囲内とすることが重要である。均質化温度が５６０℃未満では後述の第２中間焼鈍の効果が得られず、後述の熱間圧延工程や第１冷間圧延工程においてクラックが発生し易く、最終板材の耳率が高くなる。また、均質化温度が６１０℃を超えると、鋳塊が溶融するおそれがある。 "Homogenization treatment"
Next, a homogenization process is performed on the manufactured face cut body. The homogenization treatment is generally performed for homogenization of microsegregation generated by solidification of the molten metal, precipitation of supersaturated solid solution elements, transition of a metastable phase formed by solidification to an equilibrium phase, and the like.
In the homogenization treatment, it is important that the homogenization temperature is in the range of 560 to 610 ° C. If the homogenization temperature is less than 560 ° C., the effect of the second intermediate annealing described later cannot be obtained, cracks are likely to occur in the hot rolling process and the first cold rolling process described later, and the ear rate of the final plate material is increased. Further, if the homogenization temperature exceeds 610 ° C, the ingot may be melted.

均質化処理において、面削体は１００℃／時以下の加熱速度で均質化温度まで加熱することが好ましい。加熱速度が１００℃／時を超えると、部分的に溶融を生じるおそれがある。しかし、加熱速度が遅すぎると生産効率が低下する。以上の観点から、均質化温度までの加熱速度は１０〜１００℃／時の範囲内とすることが好ましい。
また、均質化処理において、均質化温度に保持する時間（均質化時間）は６時間以上とすることが好ましい。均質化時間が６時間未満では、均質化が充分に進行しない場合がある。しかし、均質化時間が長すぎても効果はなく生産効率が低下する。以上の観点から、好ましい均質化時間は６〜２４時間の範囲内である。この均質化処理は、均質化時間が比較的長いので、通常、バッチ方式の炉中に置くことで行われる。
本実施形態おいて、均質化処理の後さらに面削体を４８０〜５６０℃まで冷却し、熱間圧延を開始する。４８０〜５６０℃の温度範囲での保持時間（均熱時間）は、１〜１２時間の範囲内で行うことができる。 In the homogenization treatment, it is preferable to heat the face milling body to a homogenization temperature at a heating rate of 100 ° C./hour or less. If the heating rate exceeds 100 ° C./hour, melting may occur partially. However, if the heating rate is too slow, the production efficiency decreases. From the above viewpoint, the heating rate up to the homogenization temperature is preferably within a range of 10 to 100 ° C./hour.
In the homogenization treatment, the time for maintaining the homogenization temperature (homogenization time) is preferably 6 hours or more. If the homogenization time is less than 6 hours, the homogenization may not proceed sufficiently. However, if the homogenization time is too long, there is no effect and the production efficiency is lowered. From the above viewpoint, the preferable homogenization time is in the range of 6 to 24 hours. Since the homogenization time is relatively long, this homogenization treatment is usually performed by placing it in a batch type furnace.
In this embodiment, after the homogenization treatment, the face mill is further cooled to 480 to 560 ° C., and hot rolling is started. The holding time (soaking time) in the temperature range of 480 to 560 ° C. can be performed within a range of 1 to 12 hours.

「熱間圧延」
熱間圧延は、熱間粗圧延およびそれに続く熱間仕上げ圧延よりなり、本発明においては、シングルミルのリバース式熱間仕上圧延機を使用して熱間仕上げ圧延を行う。
熱間圧延工程においては、図１に示すように、熱間粗圧延機２０を用いて板厚２０ｍｍ程度まで熱間粗圧延した後、熱間仕上圧延機３０を用いて板厚２〜５ｍｍまで熱間圧延する。 "Hot rolling"
The hot rolling includes hot rough rolling and subsequent hot finish rolling. In the present invention, hot finish rolling is performed using a single-mill reverse hot finish rolling mill.
In the hot rolling process, as shown in FIG. 1, after hot rough rolling to a thickness of about 20 mm using a hot roughing mill 20, to a thickness of 2 to 5 mm using a hot finish rolling mill 30. Hot rolled.

図１に示す熱間粗圧延機２０は、例えば上下のワークロール２１、２２、およびバックアップロール２３、２４と、複数の搬送ローラが配列された搬送路４を備え、搬送されてきたアルミニウム合金の板材５をワークロール２１、２２間を通過させて目的の厚さに圧延する装置である。図１において、ワークロール２１、２２の左右両側の搬送路４、６から交代交代に繰り返しアルミニウム合金の板材５をワークロール２１、２２に供給して順次粗圧延することにより、熱間粗圧延機２０は板材５を必要な厚さまで圧延して板材７とすることができる。   The hot rough rolling machine 20 shown in FIG. 1 includes, for example, upper and lower work rolls 21 and 22, backup rolls 23 and 24, and a conveyance path 4 in which a plurality of conveyance rollers are arranged, and is made of an aluminum alloy that has been conveyed. This is an apparatus for rolling the plate 5 to a desired thickness by passing between the work rolls 21 and 22. In FIG. 1, a hot roughing mill is provided by repeatedly supplying and alternately rolling aluminum alloy plate materials 5 to the work rolls 21 and 22 from the conveyance paths 4 and 6 on both the left and right sides of the work rolls 21 and 22. 20 can roll the plate 5 to a required thickness to form a plate 7.

図１に示す熱間仕上圧延機３０は、シングルミルのリバース式熱間仕上圧延機であり、例えば上下のワークロール３１、３２およびバックアップロール３３、３４と、これらロールの入り側に設置されたリール型の送出巻取装置３５と、出側に設置されたリール型の送出巻取装置３６とを具備してなる。この熱間仕上圧延機３０は、送出巻取装置３５から送り出してワークロール３１、３２間を通過させて熱間圧延した板材を送出巻取装置３６で巻き取る操作と、送出巻取装置３６から再度ワークロール３１、３２間を通過させて熱間圧延した板材を送出巻取装置３５で巻き取る操作を繰り返し必要回数行うとともに、圧延操作の度に徐々にワークロール３１、３２間の間隔を調節することにより、アルミニウム合金の板材を目的の板厚まで熱間圧延する装置である。   The hot finish rolling mill 30 shown in FIG. 1 is a single-mill reverse hot finish rolling mill, for example, upper and lower work rolls 31 and 32 and backup rolls 33 and 34 and installed on the entrance side of these rolls. A reel-type delivery winding device 35 and a reel-type delivery winding device 36 installed on the outlet side are provided. The hot finish rolling mill 30 is configured to wind a sheet material that is hot-rolled from the feed winder 35 and passed between the work rolls 31 and 32 by the feed winder 36, and from the feed winder 36. The operation of winding the sheet material hot-rolled by passing between the work rolls 31 and 32 again with the feed winder 35 is repeated as many times as necessary, and the interval between the work rolls 31 and 32 is gradually adjusted for each rolling operation. By doing so, it is an apparatus for hot rolling an aluminum alloy plate material to a target plate thickness.

前記均質化処理後、炉から取り出したスラブは通常直ちに熱間粗圧延を開始するが、スラブ温度が５００℃未満にならなければ、熱間粗圧延開始を遅延してもよい。熱間粗圧延のパス数は、鋳塊（スラブ）厚さ、仕上げ厚さ、スラブ幅、合金組成などに依存するが、十数パス〜二十数パスの範囲が一般的である。
熱間粗圧延は、圧延材が厚い間は、通常圧延機の前後に搬送テーブルが設置された１スタンド式粗圧延機（図１に示す熱間粗圧延機２０）を用いて圧延する。しかし、板が薄くなると、必要な搬送テーブル長が長くなり、板の自重によるたるみも大きくなり、板の冷却も生じ易くなる。そのため、搬送テーブルで保持するには、板厚が十数ｍｍ以上必要である。この最低板厚は、コイル重量や板幅に依存するが、工業的に用いられている重量・幅の場合、１６ｍｍ程度以上であることが好ましい。
上述の厚さよりもアルミニウム合金の板材が薄くなった場合に、図１に示す構成のシングルミルのリバース式熱間仕上圧延機で熱間仕上げ圧延を行う。 After the homogenization treatment, the slab taken out from the furnace usually starts hot rough rolling immediately, but if the slab temperature does not become less than 500 ° C., the start of hot rough rolling may be delayed. The number of hot rough rolling passes depends on the ingot (slab) thickness, finished thickness, slab width, alloy composition, and the like, but is generally in the range of tens of passes to tens of passes.
In the hot rough rolling, while the rolled material is thick, rolling is usually performed using a one-stand type rough rolling mill (hot rough rolling mill 20 shown in FIG. 1) in which a conveyance table is installed before and after the rolling mill. However, if the plate is thinned, the necessary transfer table length is increased, the slack due to the weight of the plate is increased, and the plate is likely to be cooled. Therefore, in order to hold on the transfer table, the plate thickness needs to be more than 10 mm. The minimum plate thickness depends on the coil weight and plate width, but is preferably about 16 mm or more in the case of the weight and width used industrially.
When the aluminum alloy sheet becomes thinner than the above-mentioned thickness, hot finish rolling is performed with a single-mill reverse hot finish rolling mill having the configuration shown in FIG.

熱間仕上げ圧延は、シングルミルのリバース式熱間仕上圧延機を使用して行う。
圧延機の両側に巻取装置があるシングルミルのリバース式熱間仕上圧延機（図１に示す熱間仕上圧延機３０）を使用することにより、熱間仕上板厚を小さくすることができる。従って、以降の冷間圧延の圧下率を小さくできるので、冷間圧延のパス回数を削減でき、生産性を向上させることができる。これに対し、例えば、巻取装置が片方にだけ設置された熱間仕上圧延機を用いた場合、搬送テーブル上で保持できる板厚に最小値が存在するために、熱間圧延で圧延可能な最小板厚が増加することになる。このため、熱間圧延後の冷間圧下率が増加する。 Hot finish rolling is performed using a single-mill reverse hot finish rolling mill.
By using a single-mill reverse hot finish rolling mill (hot finish rolling mill 30 shown in FIG. 1) having a winding device on both sides of the rolling mill, the hot finish plate thickness can be reduced. Therefore, since the reduction ratio of the subsequent cold rolling can be reduced, the number of cold rolling passes can be reduced and the productivity can be improved. On the other hand, for example, when a hot finish rolling mill in which the winding device is installed only on one side is used, there is a minimum value for the plate thickness that can be held on the transfer table, so that it can be rolled by hot rolling. The minimum plate thickness will increase. For this reason, the cold rolling reduction after hot rolling increases.

前述の如く、熱間圧延の仕上り板厚の薄肉化は、冷間圧延パス回数の削減による生産性の向上に寄与する。そのため、本発明において、熱間仕上げ圧延の仕上げ板厚は、２〜５ｍｍの範囲内とする。仕上げ板厚が２ｍｍ未満では第１冷間圧延の圧下率が不足し、低い耳率が得られない。仕上げ板厚が５ｍｍを超えると第１冷間圧延のパス回数が増加して生産性が低下する。   As described above, the reduction in the thickness of the finished sheet of hot rolling contributes to the improvement of productivity by reducing the number of cold rolling passes. Therefore, in the present invention, the finish thickness of the hot finish rolling is set in the range of 2 to 5 mm. If the finished sheet thickness is less than 2 mm, the reduction ratio of the first cold rolling is insufficient, and a low ear ratio cannot be obtained. If the finished plate thickness exceeds 5 mm, the number of passes of the first cold rolling increases and the productivity decreases.

熱間仕上げ圧延の最終パスは、歪速度が１０〜１５０／秒の条件下で、仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御して行う必要がある。図２は、熱間仕上げ圧延の最終パスにおける仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係を示すグラフである。本発明においては、熱間仕上げ圧延の最終パスの仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）との関係が、図２のグラフ中の斜線で示す領域内（但し、斜線で示された台形の境界線上の点を含む）となるように制御する。ここで、仕上り温度ｙ（℃）とは、熱間仕上げ圧延の最終パス後、コイルに巻き取った直後の板材の温度である。   In the final pass of the hot finish rolling, the relationship between the finishing temperature y (° C.) and the finished sheet thickness x (mm) is 240 ≦ y ≦ 20x + 240 (provided that the strain rate is 10 to 150 / second). ≦ x ≦ 5.0) must be controlled. FIG. 2 is a graph showing the relationship between the finished temperature y (° C.) and the finished sheet thickness x (mm) in the final pass of hot finish rolling. In the present invention, the relationship between the finishing temperature y (° C.) of the final pass of hot finish rolling and the finished sheet thickness x (mm) is within the region indicated by the oblique lines in the graph of FIG. 2 (however, indicated by the oblique lines). (Including points on a trapezoidal boundary). Here, the finishing temperature y (° C.) is the temperature of the plate material immediately after being wound around the coil after the final pass of hot finish rolling.

熱間仕上げ圧延の最終パスの仕上り温度ｙ（℃）を図２の斜線領域内となるように、２４０〜３４０℃の範囲内とするのは、熱間圧延後の再結晶を制御するためである。これは、
熱間仕上げ板厚が薄くなるほど、第１中間焼鈍時の歪導入量が低下するため、第２中間焼鈍後に０−９０°耳が発達しにくくなり、該板材より缶を製造すると、耳率が高くなる傾向があるためである。耳率を低下させるためには第１中間焼鈍時に圧延集合組織を残存させる必要があり、すなわち、熱間圧延後の板材における再結晶率を制御する必要がある。２４０≦ｙ≦２０ｘ＋２４０を満たすように仕上り温度ｙ（℃）を制御することにより、熱間圧延後の再結晶率を小さくすることができる。 The reason why the finishing temperature y (° C.) of the final pass of hot finish rolling is in the range of 240 to 340 ° C. so as to be in the hatched region in FIG. 2 is to control recrystallization after hot rolling. is there. this is,
Since the amount of strain introduced during the first intermediate annealing decreases as the hot finish plate thickness decreases, it becomes difficult for the 0-90 ° ears to develop after the second intermediate annealing. This is because it tends to be higher. In order to reduce the ear ratio, it is necessary to leave the rolling texture during the first intermediate annealing, that is, it is necessary to control the recrystallization rate in the plate after hot rolling. By controlling the finishing temperature y (° C.) so as to satisfy 240 ≦ y ≦ 20x + 240, the recrystallization rate after hot rolling can be reduced.

図２に示すように、熱間仕上げ圧延の最終パスの仕上り温度ｙ（℃）の下限値は２４０℃（一定）である。仕上り温度ｙ（℃）が２４０℃未満では以降の冷間圧延工程でサイドクラックが発生し歩留まりが低下するおそれがある。また、熱間仕上げ圧延の最終パスの仕上り温度ｙ（℃）の上限値は、仕上り板厚で異なるが、仕上り温度ｙ（℃）が２０ｘ＋２４０を超える（すなわち、図２に示す斜線部の上方となる）と、低い耳率のアルミニウム缶の製造に適したアルミニウム合金板が得られない。
ここで、図２に示すように、仕上り板厚ｘ（ｍｍ）が厚いほど仕上り温度ｙ（℃）の許容範囲が広くなっているのは、前述の如く、第１冷間圧延の圧下率の大きさが、得られる板材を用いてアルミニウム缶を製造する際の耳率に影響するためである。仕上り板厚が薄くなる（すなわち、第１冷間圧延の圧下率が小さくなる）ほど、熱間圧延後の再結晶率をより小さくすることが必要となり、温度制御する範囲もより厳密になる。 As shown in FIG. 2, the lower limit value of the finishing temperature y (° C.) in the final pass of hot finish rolling is 240 ° C. (constant). If the finished temperature y (° C.) is less than 240 ° C., side cracks may occur in the subsequent cold rolling process, which may reduce the yield. Further, the upper limit value of the finishing temperature y (° C.) of the final pass of hot finish rolling differs depending on the finished sheet thickness, but the finishing temperature y (° C.) exceeds 20x + 240 (that is, above the shaded portion shown in FIG. In this case, an aluminum alloy plate suitable for the production of an aluminum can with a low ear rate cannot be obtained.
Here, as shown in FIG. 2, the larger the finished sheet thickness x (mm), the wider the allowable range of the finished temperature y (° C.). This is because the size affects the ear rate when an aluminum can is manufactured using the obtained plate material. The thinner the finished sheet thickness (that is, the lower the reduction ratio of the first cold rolling), the smaller the recrystallization rate after hot rolling becomes, and the more strictly the range of temperature control.

熱間仕上げ圧延の最終パスの歪速度は１０〜１５０／秒の範囲内とする。熱間仕上げ圧延の最終パスの歪速度が１０／秒未満では、材料温度が低下し過ぎるので熱間圧延の仕上り温度を２４０℃以上に保てない。熱間仕上げ圧延の最終パスの歪速度が１５０／秒を超えると、圧延中に生じる転位密度が高くなり材料温度も増加するので、圧延直後に冷却するまでに再結晶が生じてしまい第１冷間圧延前の歪量が小さくなる。
このように、熱間圧延の仕上り板厚と仕上り温度を図２に示す斜線範囲内に制御することにより、以降の第１中間焼鈍時の歪導入量を確保することができ、加工にあたって耳率を低く抑えることができるアルミニウム合金板を得ることができる。 The strain rate of the final pass of the hot finish rolling is in the range of 10 to 150 / second. If the strain rate of the final pass of hot finish rolling is less than 10 / second, the material temperature will be too low, so the finishing temperature of hot rolling cannot be kept at 240 ° C. or higher. If the strain rate in the final pass of hot finish rolling exceeds 150 / sec, the dislocation density generated during rolling increases and the material temperature also increases, so recrystallization occurs before cooling immediately after rolling, so that the first cooling The amount of strain before hot rolling is reduced.
In this way, by controlling the finished thickness and temperature of hot rolling within the hatched range shown in FIG. 2, it is possible to ensure the amount of strain introduced during the subsequent first intermediate annealing, and the ear ratio during processing Can be obtained.

熱間仕上げ圧延開始板厚は、具体的には１６〜３０ｍｍの範囲内であることが好ましい。熱間仕上げ圧延開始板厚が１６ｍｍ未満ではテーブル上での弛みが大きくなり、板幅が大きい材料を使用できない。熱間仕上げ圧延板厚が３０ｍｍを超えるようであると、第１パス後の板厚が大きくなり過ぎ、コイルに巻き取ることが困難になる。   Specifically, the hot finish rolling start plate thickness is preferably in the range of 16 to 30 mm. When the hot finish rolling start plate thickness is less than 16 mm, the slack on the table becomes large, and a material having a large plate width cannot be used. If the hot finish rolled plate thickness exceeds 30 mm, the plate thickness after the first pass becomes too large, and it is difficult to wind the coil around the coil.

「第１冷間圧延」
第１冷間圧延工程においては、前記の熱間圧延を施した後に冷却した板材を、圧下率２０〜７５％の範囲となるように冷間圧延する。第１冷間圧延の圧下率が７５％を超えると、冷間圧延のパス回数が増加して生産性が低下する。一方、第１冷間圧延の圧下率が２０％未満では、第１中間焼鈍時の歪導入量が不足するため、第２中間焼鈍後に０−９０°耳が発達しにくくなり、得られたアルミニウム板材を加工した際に低い耳率が得られない。第１冷間圧延の圧下率を２０〜７５％の範囲内とすることにより、加工にあたって耳率を低く抑えることができるアルミニウム合金板を、良好な生産性で製造できる。 "First cold rolling"
In the first cold rolling step, the plate material cooled after the hot rolling is cold-rolled so that the reduction ratio is in the range of 20 to 75%. If the rolling reduction of the first cold rolling exceeds 75%, the number of cold rolling passes increases and the productivity is lowered. On the other hand, if the reduction ratio of the first cold rolling is less than 20%, the amount of strain introduced during the first intermediate annealing is insufficient, so that the 0-90 ° ear is less likely to develop after the second intermediate annealing, and the resulting aluminum When processing a plate material, a low ear rate cannot be obtained. By setting the reduction ratio of the first cold rolling within the range of 20 to 75%, an aluminum alloy plate that can keep the ear rate low during processing can be manufactured with good productivity.

「第１中間焼鈍」
第１中間焼鈍工程は、前記第１冷間圧延後の板材に対し、図３に基本構成を示す連続焼鈍装置を用いて加熱速度１０〜２００℃／秒の範囲（１０℃／秒以上、２００℃／秒以下の範囲）で加熱し、保持温度３３０〜４００℃の範囲（３３０℃以上、４００℃以下の範囲）に０〜３０秒（０秒以上、３０秒以下）保持し、冷却速度１０〜２００℃／秒の範囲（１０℃／秒以上、２００℃／秒以下の範囲）で冷却を行う。 "First intermediate annealing"
In the first intermediate annealing step, the plate material after the first cold rolling is subjected to a heating rate of 10 to 200 ° C./second using a continuous annealing apparatus having a basic configuration shown in FIG. At a holding temperature of 330 to 400 ° C. (range of 330 ° C. or more and 400 ° C. or less) for 0 to 30 seconds (0 to 30 seconds) and a cooling rate of 10 Cooling is performed in a range of ˜200 ° C./second (range of 10 ° C./second or more and 200 ° C./second or less).

図３に連続焼鈍装置（Continuous Annealing Line：略称ＣＡＬ）の基本構成例を示すが、この例の連続焼鈍装置４０は、供給ロール４１から長尺のアルミニウム合金の板材４２を引き出して緩衝装置４３を介して数１０ｍ〜１００ｍ程度の長い炉本体４４に供給し、この炉本体４４内で移動中に前記の条件で焼鈍し、焼鈍後に炉本体４４から引き出し、緩衝装置４６を介して巻取ロール４７に巻き取ることができる装置である。この連続焼鈍装置４０によれば、炉本体４４を通過するアルミニウム合金の板材４２を連続単体処理できるために、バッチ式の焼鈍炉よりもより正確な加熱条件と冷却条件で焼鈍処理を行うことができる。
そして、連続焼鈍装置４０ならば、アルミニウム合金の板材４２を供給ロール４１に巻き付けた状態のコイルの幅や径が異なっても、換言するとアルミニウム合金の板材４２の幅や厚さ、処理するべき長さが異なっていても、製造したい順番に焼鈍処理できるために、同一の大きさのコイルのみを焼鈍炉に搬入して焼鈍していたバッチ式の焼鈍炉の場合に比べて中間在庫の増加を抑えることができる。 FIG. 3 shows a basic configuration example of a continuous annealing device (Continuous Annealing Line: abbreviated CAL). The continuous annealing device 40 of this example draws a long aluminum alloy plate 42 from a supply roll 41 to provide a shock absorber 43. Is supplied to a long furnace body 44 of about several tens to 100 m through, annealed under the above-mentioned conditions while moving in the furnace body 44, pulled out from the furnace body 44 after annealing, and taken up by a winding roll 47 through a shock absorber 46. It is a device that can be wound around. According to this continuous annealing apparatus 40, since the aluminum alloy plate material 42 passing through the furnace body 44 can be continuously processed alone, the annealing process can be performed under more accurate heating conditions and cooling conditions than the batch type annealing furnace. it can.
And if it is the continuous annealing apparatus 40, even if the width | variety and diameter of the coil of the state which wound the aluminum alloy board | plate material 42 around the supply roll 41 differ, in other words, the width | variety and thickness of the aluminum alloy board | plate material 42, and the length which should be processed Even if the lengths are different, annealing can be performed in the order in which they are to be manufactured.Therefore, the intermediate stock is increased compared to the case of the batch type annealing furnace in which only coils of the same size are brought into the annealing furnace and annealed. Can be suppressed.

この焼鈍工程は、アルミニウム合金板材を半軟化状態にもたらすものであって、焼鈍後の耐力；ＹＳ（Yield strength）を７０〜２００ＭＰａの範囲、より好ましくは９０〜１７０ＭＰａの範囲とすることが好ましい。
この範囲の耐力は、焼鈍温度と時間を適切に組み合わせることによって達成できるが、焼鈍温度を高くし、短時間で焼鈍した方が、後述の第二中間焼鈍後に立方体方位粒がより多く得られる。このために、加熱速度を１０℃／秒以上と高くし、３３０℃以上の高温に急速に加熱し、３０秒以下の短時間で適切な範囲まで軟化させる。
焼鈍温度が３３０℃未満では十分な軟化が得られず結果的に耳率が高くなる。焼鈍温度が４００℃を越えまたは保持時間が３０秒を越えると軟化が過剰となって耳率が高くなる。なお、保持時間０秒とは、目標温度に到達後直ちに冷却することである。 This annealing step brings the aluminum alloy sheet material into a semi-softened state, and the yield strength after annealing; YS (Yield strength) is preferably in the range of 70 to 200 MPa, more preferably in the range of 90 to 170 MPa.
The yield strength in this range can be achieved by appropriately combining the annealing temperature and time. However, when the annealing temperature is increased and annealing is performed in a short time, more cube-oriented grains are obtained after the second intermediate annealing described later. For this purpose, the heating rate is increased to 10 ° C./second or higher, rapidly heated to a high temperature of 330 ° C. or higher, and softened to an appropriate range in a short time of 30 seconds or shorter.
If the annealing temperature is less than 330 ° C., sufficient softening cannot be obtained, resulting in a high ear rate. When the annealing temperature exceeds 400 ° C. or the holding time exceeds 30 seconds, the softening becomes excessive and the ear rate increases. Note that the holding time of 0 seconds means cooling immediately after reaching the target temperature.

「第２冷間圧延」
次に、第１中間焼鈍後の板材に対し、圧下率１０〜２５％の範囲内となるように冷間圧延を施す。第２冷間圧延の圧下率を１０〜２５％の範囲内とすることにより、後述する第２中間焼鈍後に０−９０°耳を発達させることができるので、結果的に、後述する最終冷延工程において、最終冷延率が６０％以上の条件でも低耳率の板材を得ることができる。
第２冷間圧延の圧下率が１０％未満では工程全体として圧延パス数が増大して生産効率が低下する可能性があり好ましくない。第２冷間圧延の圧下率が２５％を越えると、耳率が高くなる。 "Second cold rolling"
Next, cold rolling is performed on the plate material after the first intermediate annealing so that the rolling reduction is within a range of 10 to 25%. By setting the reduction ratio of the second cold rolling within the range of 10 to 25%, the 0-90 ° ear can be developed after the second intermediate annealing described later, and as a result, the final cold rolling described later. In the process, a plate material having a low earing rate can be obtained even under a condition where the final cold rolling rate is 60% or more.
If the reduction ratio of the second cold rolling is less than 10%, the number of rolling passes as a whole process may increase and the production efficiency may decrease, which is not preferable. When the reduction ratio of the second cold rolling exceeds 25%, the ear ratio increases.

「第２中間焼鈍」
第２中間焼鈍工程は、前記第２冷間圧延後の板材に対し、図３に基本構成を示す連続焼鈍装置を用いて加熱速度１０〜２００℃／秒の範囲（１０℃／秒以上、２００℃／秒以下の範囲）で加熱し、保持温度５００〜６００℃の範囲（５００℃以上、６００℃以下の範囲）に０〜３０秒（０秒以上、３０秒以下）保持し、冷却速度１０〜２００℃／秒の範囲（１０℃／秒以上、２００℃／秒以下の範囲）で冷却を行う。 "Second intermediate annealing"
In the second intermediate annealing step, the sheet material after the second cold rolling is subjected to a heating rate in the range of 10 to 200 ° C./second (at least 10 ° C./second, 200 ° C. using a continuous annealing apparatus having a basic configuration shown in FIG. At a holding temperature of 500 to 600 ° C. (range of 500 ° C. or more and 600 ° C. or less) for 0 to 30 seconds (0 seconds or more and 30 seconds or less) and a cooling rate of 10 Cooling is performed in a range of ˜200 ° C./second (range of 10 ° C./second or more and 200 ° C./second or less).

この第２中間焼鈍工程は、前述の均質化処理から第２冷間圧延までの工程を順次施した板材を十分に再結晶させ、適量の立方体方位組織を発達させ、０−９０゜耳が発生する軟質材を得る工程である。
この第２中間焼鈍工程では、焼鈍温度を低くし、長時間かけて再結晶させた方が、再結晶で得られる立方体方位粒の量が多くなる。しかしながら、前述の均質化処理から第２冷間圧延までの工程を前述の条件で実施し、かつ、後述の如く最終冷間圧延の圧下率を６０〜７５％と低い値に設定しているので、低温で長時間かけて再結晶させると、立方体方位粒が過剰となり好ましくない。したがって、加熱速度を１０℃／秒以上とし、５００℃以上に加熱して、短時間で再結晶を完了させる。 In this second intermediate annealing step, the plate material subjected to the steps from the above-mentioned homogenization to the second cold rolling is sufficiently recrystallized to develop an appropriate amount of cube orientation structure, and 0-90 ° ears are generated. This is a process for obtaining a soft material.
In the second intermediate annealing step, the amount of cubic orientation grains obtained by recrystallization increases when the annealing temperature is lowered and recrystallization is performed for a long time. However, since the steps from the homogenization process to the second cold rolling are performed under the above-described conditions, and the reduction ratio of the final cold rolling is set to a low value of 60 to 75% as described later. If recrystallization is performed at a low temperature for a long time, the cubic orientation grains become excessive, which is not preferable. Therefore, the heating rate is set to 10 ° C./second or more, and the recrystallization is completed in a short time by heating to 500 ° C. or more.

また、５００℃以上に加熱することで、Ｓｉ、Ｃｕ、Ｍｇなどが溶体化されるため、加工硬化性が増加し、析出硬化性が付与されるために、最終冷間圧延の圧下率を６０〜７５％と低い値としても、充分な材料強度が得られる。溶体化効果を高めるためには、加熱温度を高くし、保持時間を長くすることが好ましいが、加熱温度が高すぎると、板の破断が生じ易いので、加熱温度の上限は６００℃とした。加熱時間を長くするためには、連続焼鈍炉の炉長を長くするか、板の通板スピードを遅くする必要があり、いずれも生産コストを増加する要因となる。そこで、上限は３０秒とした。また、冷却速度が遅すぎても、生産性が低下するため、下限を１０℃／秒とした。また、加熱／冷却速度が２００℃／秒を超えると、板材に歪が発生し易くなる。なお、保持時間０秒とは、目標温度に到達後直ちに冷却することである。   Moreover, since Si, Cu, Mg, etc. are formed into a solution by heating to 500 ° C. or higher, work hardening is increased and precipitation hardening is imparted. Even when the value is as low as ˜75%, sufficient material strength can be obtained. In order to enhance the solution effect, it is preferable to increase the heating temperature and lengthen the holding time. However, if the heating temperature is too high, the plate tends to break, so the upper limit of the heating temperature was set to 600 ° C. In order to lengthen the heating time, it is necessary to lengthen the length of the continuous annealing furnace or to slow down the plate passing speed, which both increase the production cost. Therefore, the upper limit is set to 30 seconds. Further, even if the cooling rate is too slow, the productivity is lowered, so the lower limit was set to 10 ° C./second. On the other hand, when the heating / cooling rate exceeds 200 ° C./second, the plate material is likely to be distorted. Note that the holding time of 0 seconds means cooling immediately after reaching the target temperature.

「最終冷間圧延」
第２中間焼鈍を施した後、圧下率６０〜７５％の条件で最終板厚まで冷間圧延を施す。最終冷間圧延における圧下率が６０％未満では、ネック成形時に座屈やしわが生じ易くなる。また圧下率が７５％を超えると、耳率が高くなり、耐胴切れ性が劣化する。 "Final cold rolling"
After performing the second intermediate annealing, cold rolling is performed to the final sheet thickness under the condition of a rolling reduction of 60 to 75%. If the rolling reduction in the final cold rolling is less than 60%, buckling and wrinkles are likely to occur during neck forming. On the other hand, when the rolling reduction exceeds 75%, the ear rate increases and the resistance to torsion is deteriorated.

以上のような各条件下でアルミニウム合金の鋳塊を圧延加工を施してアルミニウム合金板材を製造することにより、アルミ缶を製造するためにカップに加工した場合に、耳率の少ないものを得ることができる。   By rolling an aluminum alloy ingot under the above conditions to produce an aluminum alloy sheet, when the cup is processed to produce an aluminum can, a product with a low ear rate is obtained. Can do.

＜耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法＞
次に、本発明に係る耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法の実施の形態について説明する。
本実施形態の耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法においては、前記組成のアルミニウム合金を溶製し、鋳造して得た鋳塊に対して均質化処理した後、熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、続いて第１冷間圧延、第１中間焼鈍、第２冷間圧延、第２中間焼鈍を順次施して、さらに最終冷間圧延を行うことにより所望の板厚の缶ボディ用アルミニウム合金板を得る。 <Method for producing aluminum alloy plate for bottle-type beverage can with low ear rate>
Next, an embodiment of a method for producing an aluminum alloy plate for a bottle-type beverage can having a low ear rate according to the present invention will be described.
In the method for producing an aluminum alloy plate for a bottle-type beverage can according to the present embodiment, the aluminum alloy having the above composition is melted and homogenized with respect to an ingot obtained by casting. Hot rolling is performed by rough rolling and subsequent hot finish rolling, followed by first cold rolling, first intermediate annealing, second cold rolling, and second intermediate annealing in sequence, and further performing final cold rolling. By carrying out, an aluminum alloy plate for can bodies having a desired plate thickness is obtained.

本実施形態のネッキング加工時に頸部耐力の増加をもたらす特徴を有する耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法は、前述の本発明に係る耳率が低い缶ボディ用アルミニウム合金板の製造方法と、均質化処理から第２中間焼鈍までの条件は同じであるが、最終冷間圧延の条件が異なる。
本実施形態のネッキング加工時に頸部耐力の増加をもたらす特徴を有する耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法においては、ネッキング加工やネジ加工で加工硬化する板材とするために、最終冷間圧延での圧下率を低くする必要がある。最終冷間圧延の圧下率が６０％未満では、ネック成形時に座屈やしわが生じ易くなる。また、圧下率が６９％を超えるとネッキング加工時に加工軟化を起こし易くなり、また、耳率も高くなる。従って、最終冷間圧延時の圧下率は、６０〜６９％の範囲で圧延するのが適する。 The method for producing an aluminum alloy plate for a bottle-type beverage can with a low ear rate, which has the characteristic of increasing neck strength at the time of necking according to this embodiment, is the aluminum alloy plate for a can body with a low ear rate according to the present invention described above. The manufacturing method and the conditions from the homogenization process to the second intermediate annealing are the same, but the conditions of the final cold rolling are different.
In the manufacturing method of an aluminum alloy plate for a bottle-type beverage can having a low ear rate, which has the feature of increasing neck strength at the time of necking of the present embodiment, in order to obtain a plate material that is work hardened by necking or screwing, It is necessary to reduce the rolling reduction in the final cold rolling. If the rolling reduction of the final cold rolling is less than 60%, buckling and wrinkles are likely to occur during neck formation. Further, when the rolling reduction exceeds 69%, it becomes easy to cause work softening during necking, and the ear rate also increases. Therefore, it is suitable that the rolling reduction during the final cold rolling is in the range of 60 to 69%.

以上のような各条件下でアルミニウム合金の鋳塊を圧延加工して得られた板材は、ボトル型飲料缶に加工するに際して十分な強度を有し、胴部、肩部と共に、特に頸部の強度に優れたボトル型飲料缶とすることができる。   The plate material obtained by rolling the aluminum alloy ingot under each of the above conditions has sufficient strength when processed into a bottle-type beverage can. It can be set as the bottle-type drink can excellent in intensity | strength.

以下に、本発明の実施例について説明するが、本発明はこれらの実施例に限定されるものではない。   Examples of the present invention will be described below, but the present invention is not limited to these examples.

表１に示す組成のアルミニウム合金を溶解し、脱ガスおよび溶湯ろ過後、半連続鋳造により厚さ６００ｍｍ、幅１１００ｍｍ、長さ４．５ｍのスラブに鋳造した。次に、前記スラブを面削後、均質化・均熱兼用炉を用いて、保持温度５６５℃かつ保持時間７時間の均質化処理を施した後、保持温度５４５℃かつ保持時間２時間の均熱処理を施した。続いて、図１に示す構成の熱間粗圧延機２０を使用して板厚２０ｍｍまで熱間粗圧延した後、図１に示すシングルミルのリバース式熱間仕上圧延機３０を使用して、熱間仕上げ圧延の最終パスの歪速度を９０／秒とし、表２に示す仕上げ板厚および仕上げ温度となるように熱間仕上げ圧延を行った。なお、表２に示す仕上げ温度は、熱間仕上げ圧延後にコイルに巻き取った直後のコイル端面で測定した温度である。また、試料Ｎｏ．１〜１６の各試料の熱間仕上げ圧延の仕上げ板厚と仕上げ温度の関係を図２のグラフにプロットした。図２中の菱形のプロット点に記された数字は表２に示す各試料のＮｏ．を示し、例えば、表２で板厚ｘ＝２．５ｍｍ、温度ｙ＝２６０℃にプロットされているのは試料Ｎｏ．６の熱間圧延条件である。   An aluminum alloy having the composition shown in Table 1 was melted, degassed and filtered with a molten metal, and then cast into a slab having a thickness of 600 mm, a width of 1100 mm, and a length of 4.5 m by semi-continuous casting. Next, after chamfering the slab, using a homogenizing and soaking furnace, a homogenization treatment is performed at a holding temperature of 565 ° C. and a holding time of 7 hours, and then the soaking is performed at a holding temperature of 545 ° C. and a holding time of 2 hours. Heat treatment was applied. Subsequently, after hot rough rolling to a plate thickness of 20 mm using the hot rough rolling machine 20 having the configuration shown in FIG. 1, using a single-mill reverse hot finish rolling mill 30 shown in FIG. The hot finish rolling was performed so that the strain rate of the final pass of hot finish rolling was 90 / second, and the finished plate thickness and finish temperature shown in Table 2 were obtained. In addition, the finishing temperature shown in Table 2 is the temperature measured on the coil end surface immediately after winding around the coil after hot finish rolling. Sample No. The relationship between the finish plate thickness of hot finish rolling and the finish temperature of each of the samples 1 to 16 is plotted in the graph of FIG. The numbers written at the diamond-shaped plot points in FIG. For example, in Table 2, the sample thickness is plotted at the plate thickness x = 2.5 mm and the temperature y = 260 ° C. 6 is a hot rolling condition.

次に、熱間圧延後の板材に表２に示す圧下率で第１冷間圧延を施した後、連続焼鈍装置を用いて同表記載の保持温度および保持時間で、常温から３３０℃までの平均加熱速度２０℃／秒、最高到達温度から７０℃までの平均冷却速度３０℃／秒の条件で第１中間焼鈍を行った。次いで、第１中間焼鈍後の板材に圧下率２０％で第２冷間圧延を施した後、連続焼鈍装置を用いて、常温から５００℃までの平均加熱速度２０℃／秒、焼鈍到達最高温度（表２に示す“温度”）５５０℃、最高到達温度および５００℃以上に保持された時間２０秒、最高到達温度から７０℃までの平均冷却速度５０℃／秒の条件で第２中間焼鈍を行った。その後、第２中間焼鈍後の板材に、表２に示す圧下率で最終冷間圧延を施し、最終板厚０．３６ｍｍのアルミニウム合金板を得た。   Next, after the first cold rolling was performed on the plate after hot rolling at the rolling reduction shown in Table 2, the temperature was maintained from room temperature to 330 ° C. at the holding temperature and holding time described in the same table using a continuous annealing apparatus. The first intermediate annealing was performed under conditions of an average heating rate of 20 ° C./second and an average cooling rate of 30 ° C./second from the highest temperature to 70 ° C. Next, after subjecting the plate material after the first intermediate annealing to the second cold rolling at a reduction rate of 20%, using a continuous annealing apparatus, the average heating rate from room temperature to 500 ° C. is 20 ° C./second, the highest temperature at which annealing is achieved. ("Temperature" shown in Table 2) The second intermediate annealing was carried out under the conditions of 550 ° C, the maximum temperature reached and the time of holding at 500 ° C or higher for 20 seconds, and the average cooling rate from the maximum temperature to 70 ° C of 50 ° C / second went. Thereafter, the plate material after the second intermediate annealing was subjected to final cold rolling at a reduction rate shown in Table 2 to obtain an aluminum alloy plate having a final plate thickness of 0.36 mm.

さらに、得られたアルミニウム合金板のブランク材を使用して、図５の工程図に従ってボトル型飲料缶に加工した。次いで、２１０℃×１０分の条件で塗装焼き付け相当の熱処理を行い、ネッキング加工前後の引張試験により耐力を測定し、エリクセンカップの耳率を測定した。結果を表３に示した。
ネッキング前の耐力測定は、塗装焼き付け相当の熱処理を行ったＤＩ缶の開口端から２０ｍｍの範囲から、平行部幅１０ｍｍ、標点間距離２５ｍｍ、肩部の半径１５ｍｍの引張試験片を圧延０°方向を中心として円周方向に切り出し、ＪＩＳ Ｚ２２４１に準拠して引張試験を行った。
ネッキング後の耐力測定は、縮径後ネジ加工前のストレートのものから平行部幅１０ｍｍ、標点間距離２５ｍｍ、肩部の半径１５ｍｍの引張試験片を圧延０°方向を中心として円周方向に切り出し、ＪＩＳ Ｚ２２４１に準拠して引張試験を行った。 Furthermore, it processed into the bottle-type drink can according to the process drawing of FIG. 5 using the blank material of the obtained aluminum alloy plate. Next, heat treatment corresponding to paint baking was performed under the conditions of 210 ° C. × 10 minutes, the yield strength was measured by a tensile test before and after necking, and the ear ratio of the Eriksen cup was measured. The results are shown in Table 3.
Yield strength measurement before necking was performed by rolling a tensile test piece with a parallel part width of 10 mm, a distance between gauge points of 25 mm, and a shoulder part radius of 15 mm from a range of 20 mm from the open end of a DI can that was subjected to heat treatment equivalent to paint baking. It cut out in the circumferential direction centering on the direction, and the tension test was done based on JISZ2241.
Yield strength measurement after necking is performed in a circumferential direction around a 0 ° direction of rolling a tensile test piece having a parallel part width of 10 mm, a distance between gauge points of 25 mm, and a shoulder radius of 15 mm from the straight one after diameter reduction and before threading. It cut out and the tension test was done based on JISZ2241.

耳率は、素材をエリクセン試験機で深絞り加工したカップの側壁高さから計算した。加工条件はポンチ径；３３ｍｍ（平頭ポンチ）、絞り比；１．７５、しわ押さえ力；３ｋＮとした。このカップの側壁高さをデジタルマイクロメーターで測定し、次式により耳率を算出した。
（全山平均高さ−全谷平均高さ）÷全谷平均高さ×１００＝耳率（％）
なお、耳率は２．５％以下を合格レベルとした。 The ear rate was calculated from the height of the side wall of the cup that was deep-drawn from the Eriksen testing machine. The processing conditions were punch diameter: 33 mm (flat head punch), drawing ratio: 1.75, wrinkle holding force: 3 kN. The side wall height of this cup was measured with a digital micrometer, and the ear rate was calculated by the following formula.
(Average height of all mountains-Average height of all valleys) ÷ Average height of all valleys x 100 = Ear rate (%)
The ear rate was 2.5% or less as an acceptable level.

また、各試料について、熱間圧延後のコイルからＪＩＳ５号引張試験片を圧延方向に平行に切り出し、ＪＩＳ Ｚ２２４１に従って引張試験を行い、熱間圧延後の板材の耐力を測定した。結果を表２に併記した。ここで、合金材において耐力と再結晶率とは密接に関連しており、再結晶率が高いほど耐力が低くなる傾向にある。従って、表２に示す熱間圧延後の耐力が高いほど、熱間圧延後の再結晶率が低くなっていることを示す。   Moreover, about each sample, the JIS5 tension test piece was cut out from the coil after a hot rolling in parallel with the rolling direction, the tension test was done according to JISZ2241, and the yield strength of the board | plate material after a hot rolling was measured. The results are shown in Table 2. Here, in the alloy material, the yield strength and the recrystallization rate are closely related, and the higher the recrystallization rate, the lower the yield strength. Therefore, the higher the yield strength after hot rolling shown in Table 2, the lower the recrystallization rate after hot rolling.

表３の結果より、本発明に係る製造方法で製造されたＮｏ．１〜Ｎｏ．６、Ｎｏ.８の試料は、缶体に加工するにあたって、いずれも耳率が低く抑えられていた。従って、本発明の製造方法により製造されたアルミニウム合金板から缶ボディを製造すれば、耳率を低く抑えることが可能となる。
また、Ｎｏ．１〜Ｎｏ．９の試料は、いずれも第１冷間圧延の圧下率が７０％以下であり、従来の製造方法よりも第１冷間圧延の圧下率を低くできる。従って、本発明の製造方法によれば、第１冷間圧延のパス回数を削減できるので、生産性が向上する。 From the results of Table 3, No. manufactured by the manufacturing method according to the present invention is shown. 1-No. The samples No. 6 and No. 8 all had a low ear rate when processed into cans. Therefore, if the can body is manufactured from the aluminum alloy plate manufactured by the manufacturing method of the present invention, the ear rate can be kept low.
No. 1-No. Each of the samples No. 9 has a reduction ratio of the first cold rolling of 70% or less, and the reduction ratio of the first cold rolling can be made lower than that of the conventional manufacturing method. Therefore, according to the manufacturing method of the present invention, since the number of passes of the first cold rolling can be reduced, productivity is improved.

最終冷間圧延の圧下率が６０〜６９％の範囲内であるＮｏ．１〜Ｎｏ．６、Ｎｏ．９の試料は、ボトル型飲料缶に加工するにあたって、いずれも耳率が低く抑えられており、ネッキング加工後に耐力が向上していた。従って、本発明の製造方法により製造されたアルミニウム合金板からボトル型飲料缶を製造すれば、耳率が低く、且つ胴部、肩部の強度と共に、材料の加工硬化が充分達成されているので、ネッキング加工やネジ加工後に特に頸部の強度が高い、ボトル型飲料缶を製造することが可能となる。   No. in which the rolling reduction of the final cold rolling is in the range of 60 to 69%. 1-No. 6, no. When the samples of 9 were processed into bottle-type beverage cans, all had low ear rates, and the yield strength was improved after necking. Therefore, if a bottle-type beverage can is produced from the aluminum alloy plate produced by the production method of the present invention, the ear rate is low, and the work hardening of the material is sufficiently achieved together with the strength of the trunk and shoulder. It becomes possible to produce a bottle-type beverage can having particularly high neck strength after necking or screwing.

熱間圧延の仕上り温度が本発明の所定範囲（図２に示すグラフの斜線領域）よりも高いＮｏ．１０の試料は、耳率が３．０％と高くなっていた。熱間圧延の仕上り温度以外の製造条件が同じであるＮｏ．１、Ｎｏ．２の試料とＮｏ．１０の試料を比較すると、熱間圧延の仕上り温度が本発明の所定範囲よりも高いＮｏ．１０の試料は、熱間圧延後の耐力がＮｏ．１、Ｎｏ．２の試料よりも低く、熱間圧延後の再結晶率が高くなっており、第１中間焼鈍時の歪導入量が不足したため、耳率が高くなっていた。   No. 2 in which the finishing temperature of hot rolling is higher than the predetermined range of the present invention (the hatched area in the graph shown in FIG. 2). Ten samples had a high ear rate of 3.0%. No. with the same manufacturing conditions other than the finishing temperature of hot rolling. 1, no. No. 2 and No. 2 When the ten samples are compared, the hot rolling finish temperature is higher than the predetermined range of the present invention. In the sample No. 10, the yield strength after hot rolling was No. 10. 1, no. Since the recrystallization rate after hot rolling was higher than that of the sample No. 2 and the strain introduction amount during the first intermediate annealing was insufficient, the ear rate was high.

熱間圧延の仕上り温度が本発明の所定範囲（図２に示すグラフの斜線領域）よりも高いＮｏ．１１の試料は、耳率が３．３％と高くなっていた。熱間圧延の仕上り温度以外の製造条件が同じであるＮｏ．３、Ｎｏ．４の試料とＮｏ．１１の試料を比較すると、熱間圧延の仕上り温度が本発明の所定範囲よりも高いＮｏ．１１の試料は、熱間圧延後の耐力がＮｏ．３、Ｎｏ．４の試料よりも低く、熱間圧延後の再結晶率が高くなっており、第１中間焼鈍時の歪導入量が不足したため、耳率が高くなっていた。   No. 2 in which the finishing temperature of hot rolling is higher than the predetermined range of the present invention (the shaded area in the graph shown in FIG. 2). Eleven samples had a high ear rate of 3.3%. No. with the same manufacturing conditions other than the finishing temperature of hot rolling. 3, no. No. 4 sample and no. 11 samples are compared, the finish temperature of hot rolling is higher than the predetermined range of the present invention. In the sample No. 11, the proof stress after hot rolling was No. 11. 3, no. Since the recrystallization rate after hot rolling was higher than the sample No. 4 and the strain introduction amount during the first intermediate annealing was insufficient, the ear rate was high.

熱間圧延の仕上り温度が本発明の所定範囲（図２に示すグラフの斜線領域）よりも高いＮｏ．１２の試料は、耳率が３．５％と高くなっていた。熱間圧延の仕上り温度以外の製造条件が同じであるＮｏ．６の試料とＮｏ．１２の試料を比較すると、熱間圧延の仕上り温度が本発明の所定範囲よりも高いＮｏ．１２の試料は、熱間圧延後の耐力がＮｏ．６の試料よりも低く、熱間圧延後の再結晶率が高くなっており、第１中間焼鈍時の歪導入量が不足したため、耳率が高くなっていた。   No. 2 in which the finishing temperature of hot rolling is higher than the predetermined range of the present invention (the hatched area in the graph shown in FIG. 2). Twelve samples had a high ear rate of 3.5%. No. with the same manufacturing conditions other than the finishing temperature of hot rolling. No. 6 sample and no. When the 12 samples are compared, the finish temperature of hot rolling is higher than the predetermined range of the present invention. Sample No. 12 has a No. of proof stress after hot rolling. Since the recrystallization rate after hot rolling was higher than the sample No. 6 and the amount of strain introduction during the first intermediate annealing was insufficient, the ear rate was high.

第１中間焼鈍の保持温度が本発明の所定範囲（３３０〜４００℃）よりも低いＮｏ．１３の試料は、充分な軟化が得られず、耳率が４．９％と高くなっていた。
第１中間焼鈍の保持温度が本発明の所定範囲（３３０〜４００℃）よりも高いＮｏ．１４の試料は、軟化が過剰となり、耳率が５．６％と高くなっていた。 No. 1 in which the holding temperature of the first intermediate annealing is lower than the predetermined range (330 to 400 ° C.) of the present invention. Sample 13 was not sufficiently softened and had a high ear rate of 4.9%.
No. in which the holding temperature of the first intermediate annealing is higher than the predetermined range (330 to 400 ° C.) of the present invention. Sample 14 had excessive softening and a high ear rate of 5.6%.

最終冷間圧延の圧下率が本発明の所定範囲（６０〜７５％）より低いＮｏ．１５の試料は、耳率が低く、ネッキング後に耐力も増加しているが、ボトル型飲料容器用のアルミニウム合金板としては素材強度が不足しており、且つ、ネッキング後の強度と缶底部の強度の差が大きくなり過ぎたため、ネッキング時に缶底部が座屈した。   No. 1 in which the reduction ratio of the final cold rolling is lower than the predetermined range (60 to 75%) of the present invention. Sample 15 has a low ear rate and increased yield strength after necking, but the material strength is insufficient as an aluminum alloy plate for bottle-type beverage containers, and the strength after necking and the strength of the bottom of the can Since the difference between the two became too large, the bottom of the can buckled during necking.

第１冷間圧延の圧下率が本発明の所定範囲（２０〜７５％）より低いＮｏ．１６の試料は、第１中間焼鈍時の歪導入量が不足したため、耳率が３．４％と高くなっていた。   No. 1 in which the reduction ratio of the first cold rolling is lower than the predetermined range (20 to 75%) of the present invention. Sample 16 had a high ear rate of 3.4% because the amount of strain introduced during the first intermediate annealing was insufficient.

１…ブランク材、２…カップ、３…缶体、３Ａ…耳、４、６…搬送路、５、７…板材、１０…ボトル型飲料缶、１１…胴部、１２…肩部、１３…頸部、１４…ネジ部、１５…カール部、１６…底部、２０…熱間粗圧延機、２１、２２…ワークロール、２３、２４…バックアップロール、３０…熱間仕上圧延機、３１、３２…ワークロール、３３、３４…バックアップロール、３５、３６…送出巻取装置、４０…連続焼鈍装置、４１…供給ロール、４２…アルミニウム合金板材、４３、４６…緩衝装置、４４…炉体、４７…巻取ロール。   DESCRIPTION OF SYMBOLS 1 ... Blank material, 2 ... Cup, 3 ... Can body, 3A ... Ear | edge, 4, 6 ... Conveyance path 5, 7 ... Plate material, 10 ... Bottle-type drink can, 11 ... Body part, 12 ... Shoulder part, 13 ... Neck, 14 ... Screw, 15 ... Curl, 16 ... Bottom, 20 ... Hot roughing mill, 21, 22 ... Work roll, 23, 24 ... Backup roll, 30 ... Hot finish rolling mill, 31, 32 ... Work rolls, 33, 34 ... Backup rolls, 35, 36 ... Sending and winding device, 40 ... Continuous annealing device, 41 ... Supply roll, 42 ... Aluminum alloy sheet, 43, 46 ... Shock absorber, 44 ... Furnace body, 47 ... take-up roll.

Claims (4)

質量％で、Ｓｉ：０．２〜０．４５％、Ｆｅ：０．３〜０．５５％、Ｃｕ：０．１５〜０．４％、Ｍｎ：０．８〜１．２％、Ｍｇ：０．５〜１．７％、Ｃｒ：０．００１〜０．０５％、Ｚｎ：０．０５〜０．４％、Ｔｉ：０．００１〜０．１％を含有し、残部が不可避的不純物を含むＡｌからなる組成のアルミニウム合金を溶製し、半連続鋳造して得た鋳塊を５６０〜６１０℃で均質化処理し、その後熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、該熱間仕上げ圧延の最終パスを歪速度が１０〜１５０／秒の条件下で仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御し、熱間仕上げ圧延後の耐力を１０８〜１６３ＭＰａの範囲にするとともに、続いて圧下率を２０〜７５％とする第１冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度３３０〜４００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第１中間焼鈍を行ない、続いて圧下率１０〜２０％で第２冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度５００〜６００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第２中間焼鈍を行ない、さらに圧下率６０〜７１％の条件で最終板厚まで最終冷間圧延を行うことを特徴とする耳率が低い缶ボディ用アルミニウム合金板の製造方法。   In mass%, Si: 0.2 to 0.45%, Fe: 0.3 to 0.55%, Cu: 0.15 to 0.4%, Mn: 0.8 to 1.2%, Mg: 0.5 to 1.7%, Cr: 0.001 to 0.05%, Zn: 0.05 to 0.4%, Ti: 0.001 to 0.1%, the balance being inevitable impurities An ingot obtained by melting an aluminum alloy composed of Al and semi-continuously cast is homogenized at 560 to 610 ° C., and then hot rolled by hot rough rolling and subsequent hot finish rolling. And the relationship between the finishing temperature y (° C.) and the finished sheet thickness x (mm) is 240 ≦ y ≦ 20x + 240 (provided that 2) 0.0 ≦ x ≦ 5.0) and the yield strength after hot finish rolling is in the range of 108 to 163 MPa. Then, after performing the 1st cold rolling which makes a reduction rate 20-75% continuously, using a continuous annealing apparatus, the heating rate is 10-200 ° C./second, the holding temperature is 330-400 ° C., the holding time is 0- The first intermediate annealing is performed for 30 seconds at a cooling rate of 10 to 200 ° C./second, followed by the second cold rolling at a reduction rate of 10 to 20%, and then a heating rate of 10 to 10 using a continuous annealing apparatus. Second intermediate annealing is performed under the conditions of 200 ° C./second, holding temperature of 500 to 600 ° C., holding time of 0 to 30 seconds, cooling rate of 10 to 200 ° C./second, and final plate thickness under the conditions of rolling reduction of 60 to 71%. A method for producing an aluminum alloy sheet for a can body having a low ear rate, characterized by performing final cold rolling until the end of the process. 前記熱間仕上げ圧延の仕上り板厚ｘ（ｍｍ）を２．０≦ｘ≦４．５、前記第１冷間圧延の圧下率を４５〜７０％とすることにより、耳率１．４〜２．３％のアルミニウム合金板を得ることを特徴とする請求項１に記載の耳率が低い缶ボディ用アルミニウム合金板の製造方法。 The finished sheet thickness x (mm) of the hot finish rolling is 2.0 ≦ x ≦ 4.5, and the reduction ratio of the first cold rolling is 45 to 70%, so that the ear rate is 1.4 to 2. 2. The method for producing an aluminum alloy plate for can bodies having a low ear rate according to claim 1, wherein the aluminum alloy plate is 3%. 絞り加工としごき加工とネッキング加工とネジ加工が施されて底部と胴部と肩部と頸部とが一体成形され前記頸部にネジ部が形成されてなるボトル型飲料缶を形成するための素材となるアルミニウム合金板の製造方法であり、
質量％で、Ｓｉ：０．２〜０．４５％、Ｆｅ：０．３〜０．５５％、Ｃｕ：０．１５〜０．４％、Ｍｎ：０．８〜１．２％、Ｍｇ：０．５〜１．７％、Ｃｒ：０．００１〜０．０５％、Ｚｎ：０．０５〜０．４％、Ｔｉ：０．００１〜０．１％を含有し、残部が不可避的不純物を含むＡｌからなる組成のアルミニウム合金を溶製し、半連続鋳造して得た鋳塊を５６０〜６１０℃で均質化処理し、その後熱間粗圧延およびそれに続く熱間仕上げ圧延による熱間圧延を行い、該熱間仕上げ圧延の最終パスを歪速度が１０〜１５０／秒の条件下で仕上り温度ｙ（℃）と仕上り板厚ｘ（ｍｍ）の関係が２４０≦ｙ≦２０ｘ＋２４０（但し、２．０≦ｘ≦５．０）を満たすように制御し、熱間仕上げ圧延後の耐力を１０８〜１６３ＭＰａの範囲にするとともに、続いて圧下率を２０〜７５％とする第１冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度３３０〜４００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第１中間焼鈍を行ない、続いて圧下率１０〜２０％で第２冷間圧延を行った後、連続焼鈍装置を用いて加熱速度１０〜２００℃／秒、保持温度５００〜６００℃、保持時間０〜３０秒、冷却速度１０〜２００℃／秒なる条件で第２中間焼鈍を行ない、さらに圧下率６０〜６９％の条件で最終板厚まで最終冷間圧延を行う、前記ネッキング加工時に頸部耐力の増加をもたらす特徴を有する耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法。 For forming a bottle-shaped beverage can in which a bottom part, a body part, a shoulder part, and a neck part are integrally formed by drawing, ironing, necking, and screwing, and a screw part is formed on the neck part It is a manufacturing method of an aluminum alloy plate as a material
In mass%, Si: 0.2 to 0.45%, Fe: 0.3 to 0.55%, Cu: 0.15 to 0.4%, Mn: 0.8 to 1.2%, Mg: 0.5 to 1.7%, Cr: 0.001 to 0.05%, Zn: 0.05 to 0.4%, Ti: 0.001 to 0.1%, the balance being inevitable impurities An ingot obtained by melting an aluminum alloy composed of Al and semi-continuously cast is homogenized at 560 to 610 ° C., and then hot rolled by hot rough rolling and subsequent hot finish rolling. And the relationship between the finishing temperature y (° C.) and the finished sheet thickness x (mm) is 240 ≦ y ≦ 20x + 240 (provided that 2) 0.0 ≦ x ≦ 5.0) and the yield strength after hot finish rolling is in the range of 108 to 163 MPa. Then, after performing the 1st cold rolling which makes a reduction rate 20-75% continuously, using a continuous annealing apparatus, the heating rate is 10-200 ° C./second, the holding temperature is 330-400 ° C., the holding time is 0- The first intermediate annealing is performed for 30 seconds at a cooling rate of 10 to 200 ° C./second, followed by the second cold rolling at a reduction rate of 10 to 20%, and then a heating rate of 10 to 10 using a continuous annealing apparatus. Second intermediate annealing is performed under the conditions of 200 ° C./second, holding temperature of 500 to 600 ° C., holding time of 0 to 30 seconds, cooling rate of 10 to 200 ° C./second, and final plate thickness under the conditions of a rolling reduction of 60 to 69 %. A method for producing an aluminum alloy plate for a bottle-type beverage can having a low ear rate, which has a feature of causing an increase in neck strength at the time of necking, in which the final cold rolling is performed. 前記熱間仕上げ圧延の仕上り板厚ｘ（ｍｍ）を２．０≦ｘ≦４．５、前記第１冷間圧延の圧下率を４５〜７０％とすることにより、耳率１．４〜２．３％、ネッキング後に３〜９ＭＰａ耐力が向上するアルミニウム合金板を得ることを特徴とする請求項３に記載の耳率が低いボトル型飲料缶用アルミニウム合金板の製造方法。 The finished sheet thickness x (mm) of the hot finish rolling is 2.0 ≦ x ≦ 4.5, and the reduction ratio of the first cold rolling is 45 to 70%, so that the ear rate is 1.4 to 2. The method for producing an aluminum alloy plate for a bottle-type beverage can having a low ear rate according to claim 3, wherein an aluminum alloy plate having a yield strength of 3 to 9 MPa is improved after necking.

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