JP2004124142A

JP2004124142A - Al-Mg-BASED ALLOY ROLLED SHEET TEMPERED MATERIAL HAVING EXCELLENT BENDING WORKABILITY, AND PRODUCTION METHOD THEREFOR

Info

Publication number: JP2004124142A
Application number: JP2002288446A
Authority: JP
Inventors: Naoyuki Sakuma; 佐久間　尚幸; Toshiki Muramatsu; 村松　俊樹
Original assignee: Furukawa Sky KK
Current assignee: Furukawa Sky KK
Priority date: 2002-10-01
Filing date: 2002-10-01
Publication date: 2004-04-22
Anticipated expiration: 2022-10-01
Also published as: JP4267284B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolled sheet tempered material which consists of an Al-Mg-based alloy, and has a thermal refining degree of H32 to H36, particularly, which stably has bending workability as a thick plate of about ≥1 mm by a process where intermediate annealing during cold rolling is obviated. <P>SOLUTION: The Al-Mg alloy-based rolled sheet tempered material having a thermal refining degree of H32 to H36 is obtained by using an alloy comprising 1.5 to 3.0% Mg, 0.03 to 0.35% Cr, 0.1 to 0.5% Fe and 0.05 to 0.4% Si, and the balance substantially Al as the stock. In its texture at a position in a depth of 100 μm from the sheet surface, the density in cube orientation at an inclination within 15° is ≥9 times that in random orientation. Alternatively, the Al-Mg-based alloy rolled sheet tempered material comprises one or more kinds of metals selected from 0.01 to 0.6% Mn, 0.01 to 0.3% Cu, 0.005 to 0.3% Ti and 0.01 to 0.2% Zn in addition to the above components. In the production method, the stock is hot-rolled under the conditions where the finishing temperature of rough rolling is controlled to 370 to 470°C, the logarithmic draft in the final pass of finish rolling to 0.40 to 0.85, the rolling speed in the final pass of the finishing rolling to ≥200 mm/min, and the finishing temperature in the finish rolling to 285 to 360°C, and is cold-rolled at a rolling ratio of 10 to 65%. Then, temper-rolling is performed so as to be finished to a thermal refining degree of H32 to H36. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明が属する技術分野】
この発明は、建築、土木、電気機器、その他一般の機器、船舶などの用途において、１ｍｍ程度以上の比較的厚い板として使用されるＡｌ−Ｍｇ系合金に関するものであり、特にＨ３２〜Ｈ３６相当に調質した曲げ加工性に優れるＡｌ−Ｍｇ系合金圧延板調質材に関するものである。
【０００２】
【従来の技術】
一般にＡｌ−Ｍｇ系合金、すなわちいわゆる５０００番系合金は、強度と延性とのバランスに優れていて、良好な成形性を有することなどから、従来から建築、土木、電気機器、一般機器、船舶など、種々の用途に広く使用されている。これらの用途のＡｌ−Ｍｇ系合金の代表的なものとしては、ＪＩＳ５０５２合金などがある。ところでこれらの用途に使用されるＡｌ−Ｍｇ系合金は、一般には冷間圧延のままではなく、冷間圧延により加工硬化した材料について、さらに安定化処理を目的とした調質焼鈍を施して、Ｈ３ｎ材として用いるのが通常である。すなわち、Ａｌ−Ｍｇ系合金では、冷間圧延のままでは次第に強度が低下して伸びが増加するという経時変化を示すところから、安定化処理を目的とした調質焼鈍処理を施すのが通常である。
【０００３】
なお前述のような用途では、１ｍｍ以上の比較的厚い板厚で用いることが多い。またその場合の製造方法としては、熱間圧延後に一次冷間圧延を行なって中間板厚とし、その段階で中間焼鈍を施してから最終冷間圧延を行なって最終板厚とし、その後に前述のような安定化処理を目的とした調質焼鈍を行なうのが通常である。
【０００４】
【発明が解決しようとする課題】
近年、低コスト化の要請のみならず、地球環境保全の要請からも、各種材料製造工程における省エネルギー化が重要視されるようになっている。そこで本発明者等は、前述のような用途に使用されるＡｌ−Ｍｇ系圧延板調質材についても、その製造プロセスを簡素化して、省エネルギー化を図る方策を検討している。
【０００５】
ここで、Ａｌ−Ｍｇ系合金圧延板調質材の製造における省エネルギー化のためには、熱間圧延後の冷間圧延中途における中間焼鈍を省略することが考えられる。しかしながら単純に熱間圧延後の冷間圧延の中途での中間焼鈍を省略した場合、製品板の性能、特に１ｍｍ以上の厚板での曲げ加工性を満足させることは困難である。
【０００６】
この発明は以上の事情を背景としてなされたもので、主として省エネルギーの観点から冷間圧延中途での中間焼鈍を省略しながらも、１ｍｍ程度以上の厚い最終製品板における曲げ加工性が良好なＡｌ−Ｍｇ系合金圧延板調質材を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
前述のような課題を解決するため、本発明者等が鋭意実験・検討を重ねた結果、Ａｌ−Ｍｇ系合金の成分組成を適切に調整するばかりでなく、熱間圧延条件を厳密かつ適切に制御して板の集合組織を適切に調整することによって、冷間圧延中途の中間焼鈍を省略したプロセスでも、１ｍｍ程度以上の比較的厚い板で充分な曲げ加工性を確保し得ることを見出し、この発明をなすに至った。
【０００８】
具体的には、請求項１の発明のＡｌ−Ｍｇ系合金圧延板調質材は、Ｍｇ１．５〜３．０％、Ｃｒ０．０３〜０．３５％、Ｆｅ０．１〜０．５％、Ｓｉ０．０５〜０．４％を含有し、残部がＡｌおよび不可避的不純物よりなる合金を素材とし、板表面から１００μｍの深さの位置における板表面側から測定した集合組織として、傾角１５°以内のキューブ方位密度がランダム方位の９倍以上であり、調質度Ｈ３２〜Ｈ３６とされたことを特徴とするものである。
【０００９】
また請求項２の発明のＡｌ−Ｍｇ系合金圧延板調質材は、請求項１に記載のＡｌ−Ｍｇ系合金圧延板調質材において、前記合金が、前記各成分のほか、さらにＭｎ０．０１〜０．６％、Ｃｕ０．０１〜０．３％、Ｔｉ０．００５〜０．３％、Ｚｎ０．０１〜０．２％のうちから選ばれた１種または２種以上を含有することを特徴とするものである。
【００１０】
さらに請求項３の発明のＡｌ−Ｍｇ系合金圧延板調質材の製造方法は、請求項１もしくは請求項２に記載のＡｌ−Ｍｇ系合金圧延板調質材の製造方法において、前記成分組成の合金からなる鋳塊に対し、熱間粗圧延および熱間仕上げ圧延からなる熱間圧延を、粗圧延終了温度が３７０〜４７０℃の範囲内、仕上げ圧延における最終パスの対数圧下率が０．４０〜０．８５の範囲内、仕上げ圧延における最終パスの圧延速度が２００ｍ／分以上、仕上げ圧延の終了温度が２８５〜３６０℃の範囲内となるように行ない、その後１０〜６５％の範囲内の圧延率で冷間圧延を行ない、さらに調質焼鈍として、バッチタイプの焼鈍炉において１００〜２６０℃の範囲内の温度で０．５〜１０時間の保持の加熱処理を行ない、調質度Ｈ３２〜Ｈ３６に仕上げることを特徴とするものである。
【００１１】
さらにまた請求項４の発明のＡｌ−Ｍｇ系合金圧延板調質材の製造方法は、請求項１もしくは請求項２に記載のＡｌ−Ｍｇ系合金圧延板調質材の製造方法において、前記成分組成の合金からなる鋳塊に対し、熱間粗圧延および熱間仕上げ圧延からなる熱間圧延を、粗圧延終了温度が３７０〜４７０℃の範囲内、仕上げ圧延における最終パスの対数圧下率が０．４０〜０．８５の範囲内、仕上げ圧延における最終パスの圧延速度が２００ｍ／分以上、仕上げ圧延の終了温度が２８５〜３６０℃の範囲内となるように行ない、その後１０〜６５％の範囲内の圧延率で冷間圧延を行ない、さらに調質焼鈍として、連続焼鈍炉において１５０〜３４０℃の範囲内の板到達温度で保持なしもしくは１分以内の保持の加熱処理を行ない、調質度Ｈ３２〜Ｈ３６に仕上げることを特徴とするものである。
【００１２】
【発明の実施の形態】
まずこの発明におけるＡｌ−ｍｇ系合金の成分組成の限定理由について説明する。
【００１３】
Ｍｇ：
Ｍｇの添加は、Ｍｇそれ自体の固溶による強度向上に効果があり、またＭｇは転位との相互作用が大きいため加工硬化による強度向上も期待でき、したがって要求強度を満たすためには不可欠な元素である。さらにＭｇは集合組織の制御にも有効である。但しＭｇ量が１．５％未満では、要求強度を満たすことが困難となることもあり、また他の合金成分とのバランスによっては熱間圧延でキューブ方位が発達しにくくなり、そのため後の冷間圧延後に残るキューブ方位が少なくなるため、曲げ加工性に優れた材料を得ることが困難となる。一方Ｍｇ量が３．０％を越えるような多量のＭｇの添加により得られる高強度は必要としないのが通常であり、またＭｇ量が３．０％を越えれば、熱間圧延でキューブ方位が発達しにくくなり、前記と同様に曲げ加工性に優れた材料を得ることが困難となる。そこでＭｇ添加量は１．５〜３．０％の範囲内とした。
【００１４】
Ｃｒ：
Ｃｒの添加は集合組織の制御と製品板の強度調整に不可欠である。ここで、Ｃｒ添加量が０．０３％未満でも熱間圧延でキューブ方位を容易に発達させることができるが、製品板の要求強度を満たすことが困難となる。一方Ｃｒ量が０．３５％を越えれば、Ａｌ−Ｃｒ系の粗大金属間化合物が多くなって熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなり、そのため曲げ加工性に優れた材料を得ることが困難となる。そこでＣｒ添加量は、０．０３〜０．３５％の範囲内とした。
【００１５】
Ｆｅ：
Ｆｅの添加も集合組織の制御と製品板の強度調整に不可欠である。ここで、Ｆｅ量が０．１％未満でも、熱間圧延でキューブ方位を容易に発達させることができるが、製品板の要求度を満たすことが困難となる。またＦｅを０．１％未満とするためには高純度の地金を使用しなければならないため、生産コストが高くなる。一方Ｆｅ量が０．５％を越えれば、Ａｌ−Ｆｅ−（Ｍｎ）−（Ｓｉ）系の粗大金属間化合物が多くなって熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなって、曲げ加工性に優れた材料を得ることが困難となる。また粗大金属間化合物によって材料の延性が低下し、その点からも曲げ加工性に悪影響を及ぼす。そこでＦｅ量は０．１〜０．５％の範囲内とした。
【００１６】
Ｓｉ：
Ｓｉの添加も、集合組織の制御と製品板の強度調整に不可欠である。ここで、Ｓｉ量が０．０５％未満でも、熱間圧延でキューブ方位を容易に発達させることができるが、製品板要求強度を満たすことは困難となる。またＳｉ量を０．０５％未満とするためには高純度の地金を使用しなければならないため、生産コストが高くなる。一方Ｓｉ量が０．４％を越えれば、Ａｌ−Ｆｅ−Ｓｉ−（Ｍｎ）系の粗大金属間化合物が多くなって熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなるため、曲げ加工性に優れた材料を得ることが困難となる。また粗大金属間化合物によって材料の延性が低下し、このことも曲げ加工性に悪影響を及ぼす。そこでＳｉ量は０．０５〜０．４％の範囲内とした。
【００１７】
以上の各元素のほかは、基本的にＡｌおよび不可避的不純物とすれば良いが、請求項２の発明の場合は、前記各成分元素のほか、さらにＭｎ、Ｃｕ、Ｔｉ、Ｚｎのうちの１種または２種以上を添加する。次にこれらの元素の添加理由を説明する。
【００１８】
Ｍｎ：
Ｍｎの添加は、集合組織制御と製品板の強度調整に影響を及ぼす。しかしながら、Ｍｎ添加量が０．０１％未満では、その効果はあらわれない。一方Ｍｎ量が０．６％を越えれば、Ａｌ−Ｆｅ−Ｍｎ−（Ｓｉ）系粗大金属間化合物が多くなって熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなり、曲げ加工性に優れた材料を得ることが困難となる。また粗大金属間化合物によって材料の延性が低下し、その点からも曲げ加工性に悪影響を及ぼす。そこでＭｎ添加量は０．０１〜０．６％の範囲内とした。
【００１９】
Ｃｕ：
Ｃｕの添加も製品板の強度調整に有効である。しかしながら、Ｃｕ添加量が０．０１％未満では、その効果があらわれない。一方、Ｃｕ量が０．３％を越えれば、熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなって、曲げ加工性に優れた材料を得ることが困難となる。そこでＣｕ添加量は０．０１〜０．３％の範囲内とした。
【００２０】
Ｔｉ：
Ｔｉは結晶粒微細化に有効であるが、０．００５％未満ではその効果があらわれにくく、添加する意味がない。一方Ｔｉ量が０．３％を越えれば、粗大金属間化合物が多くなって熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなって、曲げ加工性に優れた材料を得ることが困難となる。また粗大金属間化合物によって材料の延性が低下し、その点からも曲げ加工性に悪影響を及ぼす。そこでＴｉ量は０．００５〜０．３％の範囲内とした。なおＴｉにＢを加えて添加する場合もあるが、その場合のＢ量は３００ｐｐｍ以下とすることが望ましい。
Ｚｎ：
Ｚｎの添加も製品板の強度調整に効果的である。しかしながら、Ｚｎ添加量が０．０１％未満では、その効果があらわれにくく、添加する意味がない。一方Ｚｎ量が０．２％を越えれば、熱間圧延でキューブ方位が発達しにくくなり、その後の冷間圧延後に残るキューブ方位が少なくなって、曲げ加工性に優れた材料を得ることが困難となる。そこでＺｎ量は０．０１〜０．２％の範囲内とした。
【００２１】
さらにこの発明のＡｌ−Ｍｇ系合金圧延板調質材の製品板においては、板の最表面から板厚方向へ１００μｍの深さの位置における板表面側から測定した集合組織、換言すれば板の表面層を厚さ１００μｍだけ削った状態で表面側から観察した集合組織として、傾角１５°以内のキューブ（Ｃｕｂｅ）方位の方位密度が、ランダム方位の９倍以上となっている必要がある。その理由について次に説明する。
【００２２】
曲げ加工においては、曲げ部先端に張力が作用し、その際に多くの転位が曲げ先端部に導入され、割れをもたらす原因となる。しかしながら、キューブ方位の活動すべり系は対称的であるため、他の結晶方位に比べて動的回復が起こりやすく、そのためキューブ方位密度が高ければ、高歪み領域まで容易に曲げ加工が可能となる。本発明者等の実験によれば、傾角１５°以内のキューブ方位の方位密度、特に板表面から１００μｍの深さの位置におけるキューブ方位密度がランダム方位の９倍以上であれば、曲げ加工時における動的回復の効果が大きく、割れが生じにくくなって曲げ加工性に優れることが判明した。すなわち、板表面から１００μｍの深さの位置でのキューブ方位密度がランダム方位の９倍に達しない場合は、良好な曲げ加工性が得られない。なおここでキューブ方位密度を板表面から１００μｍの深さの位置で規定した理由は次の通りである。すなわち、板の最表面はロールとの摩擦などの圧延条件の影響を受けて、集合組織にバラツキが生じる。そこでこのような影響を受けない部位として板表面から１００μｍの部位を選択した。
【００２３】
なお板表面から１００μｍの深さの位置でのキューブ方位密度は、例えば次のようにして測定した。すなわち、集合組織測定用の試料について、最表面から１００μｍ、１０％ＮａＯＨ浴中で溶かして、その後、機械研磨で鏡面に仕上げた。そしてキューブ方位の方位密度を、Ｘ線回折によって（２００）、（２２０）、（１１１）の不完全極点図から級数展開法で方位分布関数（ＯＤＦ）を計算して求める。またここで傾角１５°以内のキューブ方位とは、Ｂｕｎｇｅの表示法でＮＤ回転のキューブとＲＤ回転のキューブを、ψ_１角０〜１５°の範囲で５°間隔づつ（ＮＤ回転のキューブ）、φ角０〜１５°の範囲で５°間隔づづ（ＲＤ回転のキューブ）、それぞれの角度の方位密度を計算して、その和を求めたものである。なおここでψ_１角とφ角の０°は重複するから、いずれか一方の方位密度を採用した。またＯＤＦを計算する際にはゴーストピークの補正を行なうが、その際、方位によっては方位密度が負になったり、１より小さくなる場合がある。ここでの方位密度は完全にランダムな材料に対しての倍数で表すため、方位密度が負になったり、１より小さくなる場合は、方位密度を１として計算することとした。
【００２４】
次にこの発明のＡｌ−Ｍｇ系合金圧延板調質材の製造プロセスについて説明する。
【００２５】
先ず前述のような成分組成の合金をＤＣ鋳造法などの常法に従って鋳造し、得られた鋳塊に均質化処理を施してから、あるいは均質化処理を兼ねて、熱間圧延前に加熱を行ない、熱間圧延に供する。熱間圧延は粗圧延および仕上げ圧延の組合せによって行なうが、この熱間圧延の条件は、集合組織を適切に制御して、最終的に曲げ加工性に優れた製品板を得るため、厳密に規制する必要がある。すなわち、熱間粗圧延の終了温度を３７０〜４７０℃の範囲内とし、熱間仕上げ圧延の最終パスの対数圧下率を０．４０〜０．８５の範囲内、熱間仕上げ圧延の最終パスの圧延速度を２００ｍ／分以上、熱間圧延終了温度を２８５〜３６０℃の範囲内の温度に制御することが、熱間圧延からその後の熱延板コイル巻取りの段階においてキューブ方位を充分に発達させ、最終的に曲げ加工性に優れた製品板を得るために必要である。以下にこれらの熱間圧延条件の限定理由について説明する。
【００２６】
先ず熱間粗圧延の終了温度については、３７０℃未満でも熱間圧延でキューブ方位を容易に発達させることができ、製品板の曲げ加工性を向上させることができるが、加工歪みを蓄積し過ぎるため、熱間圧延においてコイルのエッジ割れが著しく生じて、生産に支障をきたしてしまう。一方熱間粗圧延終了温度が４７０℃を越えれば、熱間圧延でキューブ方位が発達しにくくなり、そのためその後の冷間圧延後に残るキューブ方位が少なくなり、曲げ加工性に優れた材料を得ることが困難となる。そこで熱間粗圧延終了温度は３７０〜４７０℃の範囲内とした。
【００２７】
次に熱間仕上げ圧延の最終パスの対数圧下率とは、熱間仕上げ圧延の最終パス前の板厚Ｈ_１と熱間仕上げ圧延終了後の板厚Ｈ_２との比の自然対数Ｌｎ（Ｈ_１／Ｈ_２）を指称しているが、この熱間仕上げ圧延の最終パスの対数圧下率が０．４０より小さい場合には、熱間圧延の終了温度が２８５℃を下回ってしまい、熱間圧延終了後にキューブ方位が発達しにくくなり、そのため熱延後の冷間圧延後に残るキューブ方位が少なくなってしまい、曲げ加工性に優れた材料を得ることが困難となる。一方、熱間仕上げ圧延の最終パスで対数圧下率が０．８５を越える高圧下圧延を行なえば、圧延中にロール焼けが生じてコーティングが発生して製品としての価値を損なう。また板への剪断作用が大きくなって、熱間圧延終了後にキューブ方位が発達しにくくなってしまう。そこで熱間仕上げ圧延最終パスの圧下率は、自然対数Ｌｎ（Ｈ_１／Ｈ_２）で０．４０〜０．８５の範囲内とした。
【００２８】
さらに、熱間仕上げ圧延の最終パスの圧延速度が２００ｍ／分未満であれば、熱間圧延の終了温度が２８５℃を下回ってしまい、熱間圧延終了後にキューブ方位が発達しにくくなり、そのため熱延後の冷間圧延後に残るキューブ方位が少なくなって、曲げ加工性に優れた材料を得ることが困難となる。そこで熱間仕上げ圧延最終パスの圧延速度を２００ｍ／分以上と規定した。
【００２９】
最終に、熱間仕上げ圧延の終了温度が２８５℃未満では、熱間圧延終了後にキューブ方位が発達しにくくなり、そのため熱延後の冷間圧延後まで残るキューブ方位が少なくなり、その結果曲げ加工性に優れた材料を得ることが困難となる。一方、熱間仕上げ圧延の終了温度が３６０℃を越えれば、圧延中にロール焼けが生じてコーティングが発生し、製品としての価値を損なってしまう。そこで熱間仕上げ圧延の終了温度は２８５〜３６０℃の範囲内とした。
【００３０】
なおこれらの熱間圧延条件は、タンデム熱延機やシングルリバース熱延機など圧延機のタイプには依存せず、汎用されているいずれの熱延機でも適用可能であることはもちろんである。また上記以外の熱間圧延条件は特に限定されるものではないが、例えば熱間圧延開始温度は４４０〜５２０℃程度とすることが望ましい。また熱間圧延の仕上げ板厚も特に限定されないが、この発明では熱間圧延後に圧延率１０〜６５％で冷間圧延を行なって、最終的に１ｍｍ程度以上の比較的厚い圧延板を得るため、熱間圧延仕上げ板厚は２．０〜４．５ｍｍ程度とすれば良い。
【００３１】
以上のようにして熱間圧延を行なって巻取った熱延板コイルに対しては、次いで冷間圧延を施す。この冷間圧延は、最終的に製品強度を得るために必要な工程である。ここで冷間圧延率が１０％未満では、目標とする製品板強度を得ることが困難となる。一方６５％を越える圧延率では、この発明で規定するＨ３２〜Ｈ３６の材質から外れてしまうおそれがある。そこで冷間圧延率は１０〜６５％の範囲内とした。
【００３２】
冷間圧延後には、最終的に安定化処理を目的として調質焼鈍を行ない、Ｈ３２〜Ｈ３６の調質度の材料とする。この調質焼鈍は、箱型タイプの焼鈍炉を用いたバッチ式の焼鈍によって行なっても、あるいは連続焼鈍炉を用いた連続焼鈍によって行なっても良い。
【００３３】
箱型タイプの焼鈍炉を用いたバッチ式によって調質焼鈍を行なう場合、その条件は、１００〜２６０℃の範囲内の温度で０．５〜１０時間保持とする必要がある。ここで、焼鈍温度が１００℃未満では、冷間圧延によって導入された転位の消滅が不充分で、製品にした場合に経時軟化が生じてしまうおそれがある。一方焼鈍温度が２６０℃を越えれば、Ｈ３ｎ材ではなく、完全に再結晶したＯ材になってしまい、要求強度を満たすことができなくなる。また保持時間が０．５時間未満では、コイル全体にわたり均一な熱処理ができず、コイル内で強度の不均一が生じてしまう。一方保持時間が１０時間を越えれば、焼鈍温度によっては完全に再結晶してしまい、要求強度を満たすことができなくなり、また生産性も低下させてしまう。そこで箱型タイプの焼鈍炉でバッチ式により調質焼鈍を行なう場合は、１００〜２６０℃の温度範囲内で、０．５〜１０時間の保持と規定した。
【００３４】
一方連続焼鈍炉を用いた連続式の調質焼鈍の場合は、板到達温度が１５０〜３４０℃の範囲内となるように加熱して保持なしもしくは１分以内の保持の条件とする必要がある。ここで、板到達温度が１５０℃未満では、冷間圧延によって導入された転位の消滅が不充分で、製品にした場合に経時軟化が生じてしまい、製品としての価値を損なう。一方板到達温度が３４０℃を越えれば、Ｈ３ｎ材ではなく、完全に再結晶したＯ材になってしまうことがあり、要求強度を満たすことができなくなる。また保持時間が１分を越えれば、完全に再結晶してしまうこともあり、要求強度を満たすことができず、また生産性も低下してしまう。そこで連続焼鈍炉で調質焼鈍を行なう場合は、１５０〜３４０℃の温度範囲で、保持なしもしくは１分以内の保持と規定した。
【００３５】
【実施例】
表１の合金Ｎｏ．１〜Ｎｏ．５に示す種々の成分組成のＡｌ合金を常法に従ってＤＣ鋳造し、得られた鋳塊に均質化処理を兼ねた加熱処理を行なって、熱間圧延を行ない、さらに冷間圧延、調質焼鈍を施してＨ３２〜Ｈ３６材とした。各プロセスの詳細な条件を表２の製造Ｎｏ．１〜Ｎｏ．９に示す。
【００３６】
得られた各製品板について、既に述べたような測定方法にしたがって、板表面から板厚方向へ１００μｍの深さの位置のキューブ方位を調べるとともに、圧延方向に対し平行な方向に試験片を切出して、機械的性質（ＹＳ）と曲げ加工性を評価したので、その結果を表３に示す。
【００３７】
なお機械的性質の評価規準は、ＪＩＳ５０５２合金のＨ３２、Ｈ３４、Ｈ３６材のＹＳ規準（Ｈ３２材：１５５ＭＰａ以上、Ｈ３４材：１７５ＭＰａ以上、Ｈ３６材：２０５ＭＰａ以上）に従い、それぞれの材質で、これらの規定を満たす場合を合格（○印）、満たさない場合を不合格（×印）と評価した。また曲げ加工性については、圧延方向に対し平行な方向に試験片を各１０片切り出し、それぞれ１８０°曲げ試験を行なった。曲げ条件はＲ／ｔ（Ｒ：曲げ治具先端の曲率、ｔ：試験片の板厚）を１．５とした。そして目視にて割れが全く認められない場合を合格（○印）、１個でも曲げＲ部に割れが認められたものを不合格（×印）と評価した。
【００３８】
【表１】

【００３９】
【表２】

【００４０】
【表３】

【００４１】
表３から明らかなように、この発明で規定する成分組成範囲内の合金Ｎｏ．１、Ｎｏ．２を用いかつ製造プロセスもこの発明で規定する条件を満たした製造Ｎｏ．１、Ｎｏ．３の場合は、キューブ方位密度がこの発明で規定する条件を満たし、優れた曲げ加工性を得ることができるとともに、機械的性質（ＹＳ）が目標とする調質度の規準をクリヤしていて、総合的に優れた性能の材料を得ることができた。
【００４２】
一方、成分組成はこの発明で規定する条件を満たしていても、熱間圧延条件がこの発明で規定する範囲を外れた製造番号２、４の場合は、機械的性質は目標材質となっているが、キューブ方位密度がこの発明で規定する条件を満たすことができず、曲げ加工性が劣ってしまった。
【００４３】
さらに、成分組成はこの発明で規定する条件を満たしていても、調質焼鈍条件が外れた製造番号５の場合、および冷間圧延条件が外れた製造番号６の場合は、いずれもキューブ方位密度はこの発明で規定する条件をクリヤして良好な曲げ加工性を得ることはできたが、機械的性質が目標材質から外れてしまった。
【００４４】
一方、製造プロセス条件はこの発明で規定する範囲内であるが、合金の成分組成がこの発明で規定する条件満たさなかった製造番号７〜９の場合は、機械的性質が目標材質から外れるかまたは曲げ加工性が劣ってしまい、総合的に不合格となった。
【００４５】
【発明の効果】
この発明によれば、Ａｌ−Ｍｇ系合金からなる調質度Ｈ３２〜Ｈ３６の圧延板調質材、特に１ｍｍ程度以上の比較的厚い圧延板調質材として、集合組織を適切に制御することにより、冷間圧延中途の中間焼鈍を省略したプロセスを適用しても、曲げ加工性が優れていてかつ機械的性質も目標材質に確実に適合する材料を安定して得ることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an Al-Mg alloy used as a relatively thick plate of about 1 mm or more in applications such as construction, civil engineering, electric equipment, other general equipment, and ships, and particularly to H32 to H36. The present invention relates to a tempered Al-Mg-based alloy rolled sheet having excellent temper bending workability.
[0002]
[Prior art]
Generally, Al-Mg-based alloys, that is, so-called No. 5000-based alloys, have a good balance between strength and ductility, and have good formability. For example, they have conventionally been used in construction, civil engineering, electric equipment, general equipment, ships, and the like. Are widely used for various applications. A typical example of the Al-Mg based alloy for these uses is JIS5052 alloy. By the way, Al-Mg based alloys used for these applications are generally not cold-rolled, but are subjected to temper annealing for the purpose of further stabilizing treatment of a material hardened by cold rolling. It is usually used as an H3n material. That is, in the case of Al-Mg-based alloys, it shows that the strength gradually decreases and the elongation increases with time in the cold rolling state. is there.
[0003]
In the above-mentioned applications, a relatively thick plate having a thickness of 1 mm or more is often used. In addition, as a manufacturing method in that case, primary cold rolling is performed after hot rolling to obtain an intermediate sheet thickness, intermediate annealing is performed at this stage, and then final cold rolling is performed to obtain a final sheet thickness. Usually, temper annealing for the purpose of such a stabilization treatment is performed.
[0004]
[Problems to be solved by the invention]
In recent years, not only the demand for cost reduction but also the demand for global environmental conservation has been emphasized for energy saving in various material manufacturing processes. Therefore, the present inventors are studying measures for energy saving by simplifying the manufacturing process of the Al-Mg rolled sheet temper used for the above-mentioned applications.
[0005]
Here, in order to save energy in the production of the tempered material of the rolled Al-Mg-based alloy, it is conceivable to omit the intermediate annealing in the middle of the cold rolling after the hot rolling. However, when the intermediate annealing in the middle of the cold rolling after the hot rolling is simply omitted, it is difficult to satisfy the performance of the product plate, particularly, the bending workability of a thick plate of 1 mm or more.
[0006]
The present invention has been made in view of the above circumstances, and Al-Al, which has good bending workability in a thick final product sheet of about 1 mm or more, while omitting intermediate annealing in the middle of cold rolling mainly from the viewpoint of energy saving. An object of the present invention is to provide a tempered material of a rolled Mg-based alloy sheet.
[0007]
[Means for Solving the Problems]
In order to solve the problems described above, the present inventors have conducted intensive experiments and studies, and as a result, not only properly adjust the component composition of the Al-Mg-based alloy, but also strictly and appropriately set the hot rolling conditions. By controlling and appropriately adjusting the texture of the sheet, it has been found that even in a process in which intermediate annealing during cold rolling is omitted, sufficient bending workability can be ensured with a relatively thick sheet of about 1 mm or more, The present invention has been made.
[0008]
Specifically, the tempered material of the rolled Al-Mg-based alloy according to the first aspect of the present invention comprises: Mg 1.5 to 3.0%, Cr 0.03 to 0.35%, Fe 0.1 to 0.5%, An alloy containing 0.05 to 0.4% of Si and the balance being Al and unavoidable impurities is used as a raw material. As a texture measured from the plate surface side at a depth of 100 μm from the plate surface, the inclination angle is within 15 °. Is 9 times or more as large as the random azimuth, and the tempering degree is H32 to H36.
[0009]
Further, the tempered aluminum-Mg based alloy rolled sheet according to the first aspect of the present invention is the Al-Mg based alloy rolled panel tempered material according to the first aspect, wherein the alloy further includes Mn0. 0.01 to 0.6%, 0.01 to 0.3% Cu, 0.005 to 0.3% Ti, and 0.01 to 0.2% Zn. It is a feature.
[0010]
Furthermore, the method for producing a tempered material of a rolled Al-Mg-based alloy sheet according to the invention of claim 3 is the method for producing a tempered material of a rolled Al-Mg-based alloy sheet according to claim 1 or 2. Hot ingot consisting of hot rough rolling and hot finish rolling is performed on the ingot made of the alloy of No. 1 in the range of 370 to 470 ° C., and the log reduction of the final pass in the finish rolling is 0. In the range of 40 to 0.85, the rolling speed of the final pass in the finish rolling is 200 m / min or more, and the finish temperature of the finish rolling is in the range of 285 to 360 ° C., and then in the range of 10 to 65%. Cold rolling is performed at a rolling rate of, and further, as temper annealing, heat treatment is performed in a batch type annealing furnace at a temperature in the range of 100 to 260 ° C for 0.5 to 10 hours to maintain the temper degree H32. ~ H36 It is characterized in that the gel.
[0011]
Furthermore, the method for producing a tempered material of a rolled Al-Mg-based alloy sheet according to the invention of claim 4 is the method for producing a tempered material of a rolled Al-Mg-based alloy sheet according to claim 1 or 2. The ingot made of the alloy having the composition is subjected to hot rolling consisting of hot rough rolling and hot finishing rolling. The rough rolling end temperature is in the range of 370 to 470 ° C., and the log reduction of the final pass in finish rolling is 0. In the range of 40 to 0.85, the rolling speed of the final pass in the finish rolling is 200 m / min or more, and the finish temperature of the finish rolling is in the range of 285 to 360 ° C., and then in the range of 10 to 65%. Cold rolling is performed at a rolling rate within the above range, and further, as temper annealing, heat treatment is performed in a continuous annealing furnace at a sheet reaching temperature in the range of 150 to 340 ° C. without holding or holding for 1 minute or less. H32-H It is characterized in that the finish 6.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the reason for limiting the component composition of the Al-mg alloy in the present invention will be described.
[0013]
Mg:
The addition of Mg is effective in improving the strength due to solid solution of Mg itself. In addition, since Mg has a large interaction with dislocations, the strength can be expected to be improved by work hardening. It is. Mg is also effective in controlling the texture. However, if the Mg content is less than 1.5%, it may be difficult to satisfy the required strength, and depending on the balance with other alloy components, the cube orientation may not be easily developed by hot rolling, and as a result, subsequent cooling may be difficult. Since the cube orientation remaining after the cold rolling is reduced, it is difficult to obtain a material having excellent bending workability. On the other hand, the high strength obtained by adding a large amount of Mg such that the Mg content exceeds 3.0% is usually not required, and if the Mg content exceeds 3.0%, the cube orientation in hot rolling is not required. Is difficult to develop, and it becomes difficult to obtain a material excellent in bending workability similarly to the above. Therefore, the added amount of Mg is set in the range of 1.5 to 3.0%.
[0014]
Cr:
The addition of Cr is indispensable for controlling the texture and adjusting the strength of the product sheet. Here, even if the Cr content is less than 0.03%, the cube orientation can be easily developed by hot rolling, but it becomes difficult to satisfy the required strength of the product sheet. On the other hand, if the Cr content exceeds 0.35%, the Al-Cr-based coarse intermetallic compound increases and the cube orientation hardly develops in hot rolling, and the cube orientation remaining after the subsequent cold rolling decreases, Therefore, it is difficult to obtain a material having excellent bending workability. Therefore, the amount of Cr added is set in the range of 0.03 to 0.35%.
[0015]
Fe:
The addition of Fe is also indispensable for controlling the texture and adjusting the strength of the product plate. Here, if the Fe content is less than 0.1%, the cube orientation can be easily developed by hot rolling, but it becomes difficult to satisfy the required degree of the product plate. In addition, in order to reduce Fe to less than 0.1%, a high-purity base metal must be used, which increases the production cost. On the other hand, if the amount of Fe exceeds 0.5%, the amount of Al-Fe- (Mn)-(Si) -based coarse intermetallic compounds increases, and the cube orientation becomes difficult to develop in hot rolling, and the subsequent cold rolling is performed. The remaining cube orientation is reduced, making it difficult to obtain a material having excellent bending workability. In addition, the ductility of the material is reduced by the coarse intermetallic compound, which also adversely affects the bending workability. Therefore, the amount of Fe is set in the range of 0.1 to 0.5%.
[0016]
Si:
The addition of Si is also indispensable for controlling the texture and adjusting the strength of the product plate. Here, if the Si content is less than 0.05%, the cube orientation can be easily developed by hot rolling, but it is difficult to satisfy the required strength of the product plate. In addition, in order to reduce the amount of Si to less than 0.05%, a high-purity base metal must be used, which increases the production cost. On the other hand, if the Si content exceeds 0.4%, the Al-Fe-Si- (Mn) -based coarse intermetallic compound increases and the cube orientation hardly develops in hot rolling, and remains after the subsequent cold rolling. Since the cube orientation is reduced, it is difficult to obtain a material having excellent bending workability. Further, the ductility of the material is reduced by the coarse intermetallic compound, which also has an adverse effect on bending workability. Therefore, the amount of Si is set in the range of 0.05 to 0.4%.
[0017]
In addition to the above elements, Al and unavoidable impurities may be basically used. In the case of the second aspect of the present invention, in addition to the above component elements, one of Mn, Cu, Ti, and Zn is further included. Add seed or two or more. Next, the reasons for adding these elements will be described.
[0018]
Mn:
The addition of Mn affects the texture control and the strength adjustment of the product plate. However, if the amount of Mn is less than 0.01%, the effect does not appear. On the other hand, if the Mn content exceeds 0.6%, the Al-Fe-Mn- (Si) -based coarse intermetallic compound increases, and the cube orientation becomes difficult to develop by hot rolling, and the cube remaining after the subsequent cold rolling is performed. Orientation decreases, and it becomes difficult to obtain a material excellent in bending workability. In addition, the ductility of the material is reduced by the coarse intermetallic compound, which also adversely affects the bending workability. Therefore, the amount of added Mn is set in the range of 0.01 to 0.6%.
[0019]
Cu:
The addition of Cu is also effective in adjusting the strength of the product plate. However, if the amount of Cu added is less than 0.01%, the effect is not exhibited. On the other hand, if the Cu content exceeds 0.3%, the cube orientation becomes difficult to develop by hot rolling, and the cube orientation remaining after the subsequent cold rolling decreases, so that a material excellent in bending workability can be obtained. It will be difficult. Therefore, the added amount of Cu is set in the range of 0.01 to 0.3%.
[0020]
Ti:
Ti is effective in refining crystal grains, but if it is less than 0.005%, the effect is difficult to appear and there is no point in adding Ti. On the other hand, if the Ti content exceeds 0.3%, the amount of coarse intermetallic compounds increases and the cube orientation hardly develops in hot rolling, and the cube orientation remaining after the subsequent cold rolling decreases, resulting in poor bending workability. It becomes difficult to obtain excellent materials. In addition, the ductility of the material is reduced by the coarse intermetallic compound, which also adversely affects the bending workability. Therefore, the amount of Ti is set in the range of 0.005 to 0.3%. Although B may be added to Ti in some cases, the amount of B is desirably 300 ppm or less.
Zn:
The addition of Zn is also effective in adjusting the strength of the product plate. However, if the amount of Zn added is less than 0.01%, the effect is unlikely to appear, and there is no point in adding Zn. On the other hand, if the Zn content exceeds 0.2%, the cube orientation becomes difficult to develop by hot rolling, the cube orientation remaining after the subsequent cold rolling decreases, and it is difficult to obtain a material excellent in bending workability. It becomes. Therefore, the Zn content is set in the range of 0.01 to 0.2%.
[0021]
Furthermore, in the product sheet of the tempered material of the rolled Al-Mg alloy sheet of the present invention, the texture measured from the sheet surface side at a position at a depth of 100 μm in the sheet thickness direction from the outermost surface of the sheet, in other words, As a texture observed from the surface side in a state where the surface layer is shaved by a thickness of 100 μm, the azimuth density of the Cube orientation within an inclination angle of 15 ° needs to be 9 times or more the random orientation. The reason will be described below.
[0022]
In bending, tension acts on the tip of the bent portion, and at this time, many dislocations are introduced into the tip of the bent portion, which causes cracks. However, since the active slip system in the cube orientation is symmetric, dynamic recovery is more likely to occur than in other crystal orientations. Therefore, if the cube orientation density is high, bending can be easily performed up to a high strain region. According to the experiments of the present inventors, if the azimuth density of the cube orientation within a tilt angle of 15 °, particularly the cube orientation density at a position at a depth of 100 μm from the plate surface is 9 times or more of the random orientation, the bending orientation is reduced. It was found that the effect of the dynamic recovery was large, cracks were hardly generated, and the bending workability was excellent. That is, if the cube orientation density at a depth of 100 μm from the plate surface does not reach nine times the random orientation, good bending workability cannot be obtained. The reason why the cube orientation density is defined at a position at a depth of 100 μm from the plate surface is as follows. That is, the outermost surface of the plate is affected by rolling conditions such as friction with a roll, and the texture is varied. Therefore, a portion 100 μm from the plate surface was selected as a portion not affected by such an influence.
[0023]
The cube orientation density at a depth of 100 μm from the plate surface was measured, for example, as follows. That is, a sample for texture measurement was dissolved in a 10% NaOH bath at 100 μm from the outermost surface, and then mirror-finished by mechanical polishing. Then, the azimuth density of the cube azimuth is obtained by calculating the azimuth distribution function (ODF) by the series expansion method from the incomplete pole figure of (200), (220), and (111) by X-ray diffraction. Here, the cube orientation within a tilt angle of 15 ° refers to a cube of ND rotation and a cube of RD rotation in Bunge's notation, and ψ ₁ angle of 0 to 15 ° at intervals of 5 ° (ND rotation cube). The azimuth density of each angle is calculated at intervals of 5 ° in the range of the φ angle of 0 to 15 ° (RD rotation cube), and the sum is obtained. Here, since the _１1 angle and the φ angle of 0 ° overlap, one of the azimuth densities was adopted. When calculating the ODF, the ghost peak is corrected. At this time, the azimuth density may be negative or smaller than 1 depending on the azimuth. Since the azimuth density here is represented by a multiple of a completely random material, when the azimuth density becomes negative or becomes smaller than 1, the calculation is made with the azimuth density as 1.
[0024]
Next, the manufacturing process of the tempered material of the rolled Al-Mg alloy sheet of the present invention will be described.
[0025]
First, an alloy having the above-described composition is cast according to a conventional method such as a DC casting method, and the obtained ingot is subjected to a homogenizing treatment, or is also used as a homogenizing treatment, and is heated before hot rolling. And subject to hot rolling. Hot rolling is performed by a combination of rough rolling and finish rolling. The conditions of this hot rolling are strictly regulated in order to properly control the texture and finally obtain a product sheet excellent in bending workability. There is a need to. That is, the end temperature of the hot rough rolling is in the range of 370 to 470 ° C., the log reduction of the final pass of the hot finish rolling is in the range of 0.40 to 0.85, and the final pass of the hot finish rolling is Controlling the rolling speed to 200 m / min or more and the hot rolling end temperature to a temperature in the range of 285 to 360 ° C. can sufficiently develop the cube orientation in the stage of coiling the hot-rolled sheet coil after hot rolling. And finally obtain a product plate excellent in bending workability. The reasons for limiting the hot rolling conditions will be described below.
[0026]
First, as for the end temperature of the hot rough rolling, even if the temperature is lower than 370 ° C., the cube orientation can be easily developed by the hot rolling, and the bending workability of the product sheet can be improved, but the processing strain is excessively accumulated. Therefore, edge cracks of the coil are significantly generated in the hot rolling, which hinders production. On the other hand, if the hot rough rolling end temperature exceeds 470 ° C., it is difficult to develop a cube orientation in the hot rolling, so that the cube orientation remaining after the subsequent cold rolling is reduced, and a material excellent in bending workability is obtained. Becomes difficult. Therefore, the hot rough rolling end temperature is set in the range of 370 to 470 ° C.
[0027]
Then the logarithmic reduction ratio in the final pass of the finish hot rolling, hot finish rolling final pass before the plate thickness H ₁ and hot finish rolling after the completion of plate thickness natural logarithm Ln of the ratio of the H ₂ (H ₁ / H ₂ ), but if the log reduction of the final pass of this hot finish rolling is smaller than 0.40, the end temperature of the hot rolling falls below 285 ° C. After the end of the rolling, the cube orientation is less likely to develop, so that the cube orientation remaining after cold rolling after hot rolling is reduced, and it is difficult to obtain a material having excellent bending workability. On the other hand, if high-pressure rolling in which the logarithmic rolling reduction exceeds 0.85 is performed in the final pass of the hot finish rolling, roll burning occurs during rolling and coating occurs, thereby impairing the value as a product. Further, the shearing action on the plate becomes large, and it becomes difficult for the cube orientation to develop after the completion of hot rolling. So a reduction ratio of the hot finish rolling final pass was in the range of 0.40 to 0.85 in the natural logarithm _{_{Ln (H 1 / H 2)}} .
[0028]
Further, if the rolling speed in the final pass of the hot finish rolling is less than 200 m / min, the end temperature of the hot rolling is lower than 285 ° C., and the cube orientation is difficult to develop after the completion of the hot rolling. Cube orientation remaining after cold rolling after elongation is reduced, and it becomes difficult to obtain a material excellent in bending workability. Therefore, the rolling speed in the final pass of the hot finish rolling was specified to be 200 m / min or more.
[0029]
Finally, if the end temperature of the hot finish rolling is lower than 285 ° C., the cube orientation is difficult to develop after the completion of the hot rolling, so that the cube orientation remaining until after the cold rolling after the hot rolling is reduced. It is difficult to obtain a material having excellent properties. On the other hand, if the end temperature of the hot finish rolling exceeds 360 ° C., roll scorching occurs during rolling and coating occurs, thereby impairing the value as a product. Therefore, the end temperature of the hot finish rolling was set to a range of 285 to 360 ° C.
[0030]
Note that these hot rolling conditions do not depend on the type of rolling mill such as a tandem hot rolling mill or a single reverse hot rolling mill, and can be applied to any general-purpose hot rolling mill. The hot rolling conditions other than those described above are not particularly limited. For example, the hot rolling start temperature is desirably about 440 to 520 ° C. The thickness of the hot-rolled sheet is not particularly limited. However, in the present invention, cold-rolling is performed at a rolling reduction of 10 to 65% after hot rolling to finally obtain a relatively thick rolled sheet of about 1 mm or more. The thickness of the hot-rolled plate may be about 2.0 to 4.5 mm.
[0031]
The hot rolled sheet coil wound by performing the hot rolling as described above is then subjected to cold rolling. This cold rolling is a process necessary for finally obtaining product strength. Here, if the cold rolling reduction is less than 10%, it is difficult to obtain a target product sheet strength. On the other hand, if the rolling ratio exceeds 65%, there is a possibility that the rolling stock may deviate from the materials of H32 to H36 specified in the present invention. Therefore, the cold rolling reduction is set in the range of 10 to 65%.
[0032]
After the cold rolling, heat treatment annealing is finally performed for the purpose of stabilization treatment, and a material having a heat treatment degree of H32 to H36 is obtained. This temper annealing may be performed by batch-type annealing using a box-type annealing furnace, or may be performed by continuous annealing using a continuous annealing furnace.
[0033]
When performing temper annealing by a batch method using a box-type annealing furnace, it is necessary to maintain the temperature at a temperature in the range of 100 to 260 ° C. for 0.5 to 10 hours. Here, if the annealing temperature is lower than 100 ° C., dislocations introduced by cold rolling are not sufficiently eliminated, and when the product is manufactured, there is a possibility that softening with time may occur. On the other hand, if the annealing temperature exceeds 260 ° C., the material becomes not the H3n material but the completely recrystallized O material, and the required strength cannot be satisfied. On the other hand, if the holding time is less than 0.5 hour, uniform heat treatment cannot be performed over the entire coil, resulting in uneven strength within the coil. On the other hand, if the holding time exceeds 10 hours, recrystallization will occur completely depending on the annealing temperature, and the required strength will not be satisfied, and the productivity will be reduced. Therefore, in the case of performing the temper annealing by a batch type in a box type annealing furnace, it is specified that the temperature is kept in a temperature range of 100 to 260 ° C. for 0.5 to 10 hours.
[0034]
On the other hand, in the case of the continuous temper annealing using the continuous annealing furnace, it is necessary to heat the sheet so that the temperature attained in the sheet is in the range of 150 to 340 ° C. and to set the condition of no holding or holding within 1 minute. . Here, if the temperature attained by the plate is lower than 150 ° C., dislocations introduced by cold rolling are not sufficiently eliminated, and when the product is manufactured, softening with time occurs, which impairs the value as a product. On the other hand, if the temperature attained by the plate exceeds 340 ° C., it may become not a H3n material but a completely recrystallized O material, and the required strength cannot be satisfied. If the holding time exceeds 1 minute, recrystallization may occur completely, and the required strength may not be satisfied, and the productivity may decrease. Therefore, in the case where the temper annealing is performed in the continuous annealing furnace, it is defined that the temperature is in a temperature range of 150 to 340 ° C. without holding or holding within 1 minute.
[0035]
【Example】
Table 1 shows the alloy Nos. 1 to No. Al alloys having various component compositions shown in FIG. 5 are DC-cast according to a conventional method, and the obtained ingot is subjected to a heat treatment which also serves as a homogenization treatment, hot-rolled, further cold-rolled, and temper-annealed. To obtain H32 to H36 materials. The detailed conditions of each process are shown in Table 2. 1 to No. It is shown in FIG.
[0036]
For each of the obtained product sheets, the cube orientation at a depth of 100 μm from the sheet surface to the sheet thickness direction is checked according to the measurement method described above, and a test piece is cut out in a direction parallel to the rolling direction. The mechanical properties (YS) and bending workability were evaluated, and the results are shown in Table 3.
[0037]
The evaluation criteria of the mechanical properties are based on the YS standard of H32, H34 and H36 materials of JIS5052 alloy (H32 material: 155 MPa or more, H34 material: 175 MPa or more, H36 material: 205 MPa or more). The case where the condition was satisfied was evaluated as pass (合格), and the case where the condition was not satisfied was evaluated as reject (x). Regarding bending workability, ten test pieces were cut out in a direction parallel to the rolling direction, and each was subjected to a 180 ° bending test. R / t (R: curvature of the tip of the bending jig, t: plate thickness of the test piece) was 1.5. Then, the case where no cracks were visually observed was evaluated as pass (、１ mark), and the case where at least one crack was recognized in the bent R portion was evaluated as rejected (x mark).
[0038]
[Table 1]

[0039]
[Table 2]

[0040]
[Table 3]

[0041]
As is clear from Table 3, the alloy No. within the component composition range specified in the present invention. 1, No. No. 2 using the manufacturing process No. 2 and satisfying the conditions specified in the present invention. 1, No. In the case of 3, the cube orientation density satisfies the condition specified in the present invention, excellent bendability can be obtained, and the mechanical property (YS) clears the target standard of temper. Thus, a material having excellent overall performance could be obtained.
[0042]
On the other hand, even if the component composition satisfies the conditions specified in the present invention, in the case of production numbers 2 and 4 where the hot rolling conditions are out of the range specified in the present invention, the mechanical properties are the target materials. However, the cube orientation density could not satisfy the conditions defined in the present invention, and the bending workability was poor.
[0043]
Further, even if the component composition satisfies the conditions specified in the present invention, in the case of production number 5 where the temper annealing conditions were deviated, and in the case of production number 6 where the cold rolling conditions were deviated, the cube orientation density was Although it was possible to obtain good bending workability by clearing the conditions specified in the present invention, the mechanical properties deviated from the target material.
[0044]
On the other hand, the manufacturing process conditions are within the range specified in the present invention, but in the case of manufacturing numbers 7 to 9 in which the component composition of the alloy does not satisfy the conditions specified in the present invention, the mechanical properties deviate from the target material or The bending workability was inferior, and the test was totally rejected.
[0045]
【The invention's effect】
According to the present invention, by appropriately controlling the texture as a rolled sheet temper having a temper degree H32 to H36 made of an Al-Mg alloy, particularly a relatively thick rolled sheet temper of about 1 mm or more. Even if a process in which intermediate annealing during cold rolling is omitted is applied, it is possible to stably obtain a material that has excellent bending workability and mechanical properties that reliably match the target material.

Claims

Mg 1.5-3.0% (mass%, the same applies hereinafter), Cr 0.03-0.35%, Fe 0.1-0.5%, Si 0.05-0.4%, the balance being Al and As a texture measured from the plate surface side at a depth of 100 μm from the plate surface using an alloy consisting of unavoidable impurities, the cube orientation density within a tilt angle of 15 ° is 9 times or more of the random orientation, An Al-Mg based alloy rolled sheet temper excellent in bending workability, characterized by a degree of H32 to H36.

2. The tempered material of the rolled Al—Mg alloy sheet according to claim 1, wherein the alloy further includes Mn 0.01 to 0.6%, Cu 0.01 to 0.3%, and Ti 0.005 in addition to the components. Al-Mg based alloy rolled sheet excellent in bending workability, characterized in that it contains one or two or more kinds selected from Zn-0.3% and Zn 0.01-0.2%. Wood.

The method for producing a tempered material of a rolled Al-Mg alloy sheet according to claim 1 or 2,
The ingot made of the alloy having the above-mentioned composition is subjected to hot rolling comprising hot rough rolling and hot finishing rolling. The rough rolling end temperature is in the range of 370 to 470 ° C., and the logarithmic rolling reduction of the final pass in finish rolling. Is in the range of 0.40 to 0.85, the rolling speed of the final pass in finish rolling is 200 m / min or more, and the finish temperature of finish rolling is in the range of 285 to 360 ° C., and thereafter 10 to 65% Cold rolling is performed at a rolling rate within the range described above, and further, as temper annealing, a heat treatment is performed in a batch type annealing furnace at a temperature within a range of 100 to 260 ° C. for 0.5 to 10 hours to hold. A method for producing a tempered material of a rolled Al-Mg-based alloy excellent in bending workability, characterized by finishing to a quality of H32 to H36.

The method for producing a tempered material of a rolled Al-Mg-based alloy according to claim 1 or 2,
The ingot made of the alloy having the above-mentioned composition is subjected to hot rolling comprising hot rough rolling and hot finishing rolling. The rough rolling end temperature is in the range of 370 to 470 ° C., and the logarithmic rolling reduction of the final pass in finish rolling. Is in the range of 0.40 to 0.85, the rolling speed of the final pass in finish rolling is 200 m / min or more, and the finish temperature of finish rolling is in the range of 285 to 360 ° C., and thereafter 10 to 65% Cold rolling is performed at a rolling rate within the range described above, and further, as temper annealing, heat treatment is performed in a continuous annealing furnace at a plate arrival temperature in the range of 150 to 340 ° C without holding or holding for 1 minute or less. A method for producing a tempered material of a rolled Al-Mg-based alloy excellent in bending workability, characterized by finishing to a quality of H32 to H36.