JP2004188429A

JP2004188429A - Method for producing copper rough-drawn wire and copper wire

Info

Publication number: JP2004188429A
Application number: JP2002356320A
Authority: JP
Inventors: Masahito Watabe; 雅人渡部; Hiromitsu Kuroda; 洋光黒田; Takao Ichikawa; 貴朗市川; Masayoshi Aoyama; 正義青山; Hiroaki Tsunoda; 博昭角田
Original assignee: Hitachi Cable Ltd
Current assignee: Hitachi Cable Ltd
Priority date: 2002-12-09
Filing date: 2002-12-09
Publication date: 2004-07-08

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing copper rough-drawn wire, of which the softening temperature is lowered, without changing production facilities thereof. <P>SOLUTION: The method for producing copper rough-drawn wire is a method for producing the wire by casting molten copper which contains impurity elements into a copper ingot and by subjecting the ingot to multistage hot-rolling. In the method, the casting is conducted at a casting temperature of ≥ 1,100°C and ≤ 1,200°C, and the final rolling in the process of the multistage hot-rolling is conducted at a rolling temperature of ≥ 300°C and ≤ 550°C. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、連続鋳造圧延による銅荒引線の製造方法及びそれによって製造された銅荒引線を冷間加工して得られる銅線に関するものである。
【０００２】
【従来の技術】
各種用途の導電材料として広く用いられる銅線は、一般的には銅荒引線を冷間伸線加工（引抜加工）して所望のサイズに加工されることが多い。従来、この銅荒引線の製造方法としては、生産性、歩留等の点から連続鋳造圧延法が主流となっており、例えば、Ｃｏｎｔｉｒｏｄ法、ＳＣＲ法、Ｐｒｏｐｅｒｚｉ法等の方法が周知となっている。
【０００３】
連続鋳造圧延設備の一例として、図２に示されるようなＣｏｎｔｉｒｏｄ式の横型（水平）連続鋳造圧延設備２１がある。この設備２１は、銅母材である電解銅板２２を溶湯２３にするシャフト炉２４と、溶湯２３を下流に導く鋳造樋２５と、鋳造樋２５の途中に設けられ、溶湯２３の温度を保持する保持炉２６と、鋳造樋２５内の溶湯２３を下方に導くノズル２７と、ノズル２７からの溶湯２３を下流に導くタンディシュ２８と、タンディシュ２８からの溶湯２３を連続鋳造して銅鋳塊２９にする横型のツインベルト式鋳造機３０と、銅鋳塊２９を圧延ロール３１，３２で多段に圧延して銅熱間圧延材３３にし、その圧延材３３を最下流の圧延ロール３４で最終圧延して銅荒引線３５にする熱間圧延加工装置３６とを備えている。
【０００４】
この設備２１では、まず、電解銅板２２がシャフト炉２４で溶解されて溶湯２３になり、その溶湯２３が鋳造樋２５および保持炉２６を経てノズル２７からタンディシュ２８に送られる。そして、溶湯２３は鋳造機３０に連続的に注湯され、鋳造機３０で銅鋳塊２９になる。銅鋳塊２９は、装置３６の圧延ロール３１，３２により、段階的に熱間圧延加工されて圧延材３３になる。この圧延材３３を圧延ロール３４で最終圧延すると、所望径の銅荒引線３５が得られる。銅荒引線３５に冷間伸線加工を施すと、各種用途の導電用線材である銅線も得られる。
【０００５】
冷間伸線加工においては、銅の軟化特性、すなわち銅の軟化温度は工業的に見て極めて重要な特性として挙げられる。例えば、銅荒引線３５から軟銅線を製造しようとする場合には、その柔軟性の点からできるだけ軟化しやすいことが要求される。また、銅荒引線３５から硬銅線を製造する場合においても、その中間段階の焼鈍工程にて加工材を十分に軟化させることが不可欠となる。
【０００６】
銅の軟化特性は、その純度（含有不純物元素あるいは不可避不純物の種類・量）、製法、加工履歴等により大きく異なる。そこで近年、より軟化しやすい銅荒引線および銅線を得るために、軟化温度に及ぼす含有不純物元素、加工履歴の影響に関して精力的に研究されている。銅は、含有不純物元素の固溶量が少ないほど、また、冷間加工の加工度を大きくするほど軟化しやすいことが知られている。
【０００７】
なお、この出願の発明に関連する先行技術文献情報としては、次のものがある。
【０００８】
【特許文献１】
特開平６−２４０４２６号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、軟化温度の低下を目的として、上述した連続鋳造圧延設備２１で溶湯２３中に固溶している微量の不純物元素を除去することは非常に難しい。
【００１０】
また、冷間加工度を増大して軟化温度を低下させようとする場合には、銅荒引線のサイズアップを図る必要がある。この場合、設備２１の改造が不可欠となり、それに伴う労力、作業工数、改造費が発生し、結果として製品のコストアップが余儀なくされるという問題がある。
【００１１】
なお、特許文献１に記載された高強度銅合金トロリー線の製造方法は、Ｓｎを０．４乃至０．７重量％含有した銅合金の圧延材を、５００℃以下の温度で仕上げ圧延して荒引線を得る方法である。ここでは、▲１▼仕上げ圧延温度が５００℃を超えると強度が不十分になる点と、▲２▼低温で仕上げ圧延するとＳｎによる導電率の低下が抑えられる点とを考慮して、仕上げ圧延温度を５００℃以下としている。したがって、荒引線およびトロリー線の軟化温度を低下させることは考慮されていない。
【００１２】
そこで、本発明の目的は、製造設備の変更を要さず、軟化温度を低下させた銅荒引線の製造方法及び銅線を提供することにある。
【００１３】
【課題を解決するための手段】
本発明は上記目的を達成するために創案されたものであり、不純物元素を含む銅の溶湯に鋳造処理を施して銅鋳塊にし、その銅鋳塊に熱間圧延加工を多段に施して銅荒引線を製造する方法において、上記鋳造処理を１１００℃以上１２００℃以下の鋳造温度で行い、上記熱間圧延加工の最終圧延を３００℃以上５５０℃以下の圧延温度で行う銅荒引線の製造方法である。
【００１４】
請求項２の発明は、上記溶湯は、酸素含有量が６００ｍａｓｓｐｐｍ以下で、かつ不純物元素が３ｍａｓｓｐｐｍ以上２００ｍａｓｓｐｐｍ以下含まれている溶銅である請求項１記載の銅荒引線の製造方法である。
【００１５】
ここでいう不純物元素とは、硫黄、鉛、ビスマス、セレン、テルルのうち一種以上の元素を含んだものである。
【００１６】
請求項３の発明は、上記銅鋳塊に、上記銅荒引線の線径が８〜３０ｍｍとなるように熱間圧延加工を多段に施した請求項１または２記載の銅荒引線の製造方法である。
【００１７】
請求項４の発明は、請求項１〜３いずれかに記載された製造方法を用いて作製した銅荒引線に、冷間加工を施して作製した銅線である。
【００１８】
【発明の実施の形態】
以下、本発明の好適実施の形態を添付図面にしたがって説明する。
【００１９】
図１は、本発明の好適実施の形態である銅荒引線の製造方法の工程を示すフローチャートである。
【００２０】
図１に示すように本発明に係る銅荒引線の製造方法は、銅母材を溶解して不純物元素を含んだ銅の溶湯（溶銅）にする溶解工程（Ｆ１）と、その銅の溶湯を鋳造して銅鋳塊にする鋳造工程（Ｆ２）と、その銅鋳塊に熱間圧延加工を多段に施して圧延材にする熱間圧延工程（Ｆ３）と、その圧延材を洗浄し巻取って銅荒引線にする洗浄・巻取り工程（Ｆ４）とを有している。さらに、次工程（Ｆ５）は、巻き取った銅荒引線を送り出し、その銅荒引線に冷間加工を施して各種用途の導電用線材である銅線にする冷間（伸線）加工工程である。
【００２１】
溶解工程（Ｆ１）から洗浄・巻取り工程（Ｆ４）までは、既存または慣用の連続鋳造圧延設備、例えば、図２で説明したＣｏｎｔｉｒｏｄ式の横型（水平）連続鋳造圧延設備２１を用いて行う。また、冷間加工工程（Ｆ５）は、既存または慣用の冷間加工装置を用いて行う。
【００２２】
図１を図２に対応させれば、溶解工程（Ｆ１）は図２のシャフト炉２４における工程に、鋳造工程（Ｆ２）は図２の鋳造機３０における工程に、熱間圧延工程（Ｆ３）は図２の熱間圧延加工装置３６における工程に、洗浄・巻取り工程（Ｆ４）は図２の圧延ロール３４と銅荒引線３５間における工程にそれぞれ相当する。
【００２３】
各工程をより詳細に説明する。溶解工程（Ｆ１）は、銅を溶解して溶銅にする工程であり、その溶銅中には酸素含有量が６００ｍａｓｓｐｐｍ以下で、かつ硫黄（Ｓ）、鉛（Ｐｂ）、ビスマス（Ｂｉ）、セレン（Ｓｅ）、テルル（Ｔｅ）のうち一種以上の元素を含んだ不純物元素が合計（総含有量）で３〜２００ｍａｓｓｐｐｍ含まれている。
【００２４】
銅中の酸素は、主としてＣｕ_２Ｏ（亜酸化銅）の形で存在する。タフピッチ銅線（酸素含有量２００〜５００ｍａｓｓｐｐｍ）の冷間伸線時にはその長手方向に張力が加わり、亜酸化銅自身が割れるか、亜酸化銅と銅マトリックスとの境界が離れる結果、ボイド（空隙）が形成されるとされている（例えば、田中浩、吉田一也，「タフピッチ銅の材料特性とカッピング欠陥」，日本塑性加工学会誌，１９８２年，第２４巻，ｐ．４７０参照。）。そして、このボイドは伸線加工が進むにつれて合体・進展することから、銅中の酸素濃度が高い場合（Ｃｕ_２Ｏ量が多い場合）には、断線に至りやすいとされている。
【００２５】
したがって、溶銅中の酸素含有量は６００ｍａｓｓｐｐｍ以下、より好ましくは実施例で後述するように、２００〜４００ｍａｓｓｐｐｍとなるようにしている。
【００２６】
Ｓ，Ｐｂ，Ｂｉ，Ｓｅ，Ｔｅは、銅中に比較的多く含まれる不純物元素、あるいは不可避不純物でもあり、銅に固溶するといずれも極微量で銅の軟化温度を著しく上昇させるものである（例えば、鈴木寿、菅野幹宏、前田貴雄、山崎伸介，「純銅加工材の軟化特性と導電性に及ぼす微量のｂ族および遷移金属元素添加の影響」，伸銅技術研究会誌，１９８４年，第２３巻，ｐ．２５−３５、および青山正義、菅野幹宏，「純銅加工材の軟化特性に及ぼすＰｂ、Ｓ、及びＯ添加の影響」，伸銅技術研究会誌，１９９６年，第３５巻，ｐ．１１０−１１７参照。）。
【００２７】
ただし、これら五種の元素は銅への固溶限が極めて小さい特徴がある（例えば、Ｒ．Ｐ．Ｅｌｌｉｏｔｔ：ＣｏｎｓｔｉｔｕｔｉｏｎｏｆＢｉｎａｒｙＡｌｌｏｙｓ，ＦｉｒｓｔＳｕｐｐｌｅｍｅｎｔ（１９８５），ｐ．３８１、およびＭ．Ｈａｎｓｅｎ，Ｋ．Ａｎｄｅｒｕｋｏ：ＣｏｎｓｔｉｔｕｔｉｏｎｏｆＢｉｎａｒｙＡｌｌｏｙｓ，（１９５８），ｐ．３０８−３０９，６０９−６１２，６２８−６２９，６３８−６４１参照。）。
【００２８】
本実施の形態では、後述するように、最終圧延を３００℃以上５５０℃以下の低い圧延温度で行っているので、熱間圧延加工中にこれら元素の銅への固溶限がさらに小さくなり、元素の析出（固溶量の減少）がより促進されて進行することになる。したがって、銅荒引線および銅線の軟化温度を低下させることができる。
【００２９】
さらに、その他の効果として、これら五種の元素と、その他の微量元素との共存による化合物の形成促進、析出促進なども期待される。
【００３０】
Ｓ，Ｐｂ，Ｂｉ，Ｓｅ，Ｔｅのうち一種以上の元素を含んだ不純物元素の総含有量を３ｍａｓｓｐｐｍ未満に調整することは非常に困難である。また、３ｍａｓｓｐｐｍ未満では、従来の製造条件でも銅荒引線および銅線の導電率の低下や表面品質の低下などの問題は認められず、銅荒引線および銅線の軟化温度に及ぼす影響が少ない。一方、Ｓ，Ｐｂ，Ｂｉ，Ｓｅ，Ｔｅのうち一種以上の元素を含んだ不純物元素の総含有量が２００ｍａｓｓｐｐｍを超えると、製造条件を変えても銅荒引線および銅線の軟化温度が過剰に上昇してしまうばかりでなく、銅荒引線および銅線の導電率の低下や表面品質の低下が引き起こされてしまう。
【００３１】
したがって、溶銅中のＳ，Ｐｂ，Ｂｉ，Ｓｅ，Ｔｅのうち一種以上の元素を含んだ不純物元素の総含有量は、３〜２００ｍａｓｓｐｐｍ、好ましくは３〜１００ｍａｓｓｐｐｍ、より好ましくは３〜５０ｍａｓｓｐｐｍ、特に好ましくは３〜２５ｍａｓｓｐｐｍとなるようにしている。
【００３２】
鋳造工程（Ｆ２）は、銅の溶湯を１１００〜１２００℃の鋳造温度で鋳造して銅鋳塊にする工程である。
【００３３】
溶湯の温度が低いとその流動性が低下し、操業が困難となる場合がある。また、溶湯の温度が高くなると、水素ガスの吸収量の増加、銅鋳塊中の空隙（ブローホール、ピンホール）量の増大により、銅荒引線および銅線の表面品質が低下する傾向にある。したがって、鋳造温度は１１００〜１２００℃にしている。
【００３４】
熱間圧延工程（Ｆ３）は、銅鋳塊に、圧延初期は６００〜９００℃の圧延温度で熱間圧延加工を施し、最終圧延は３００〜５５０℃の圧延温度で熱間加工を施して圧延材にする工程である。
【００３５】
銅荒引線および銅線の軟化温度を低下させるためには、上述した五種の元素の固容量を減少させる必要がある。そのためには、最終圧延温度の上限を五つの元素の固溶限が小さくなる温度、すなわち５５０℃以下にしている。一方、圧延温度が低くなると銅の熱間加工性が低下するので、最終圧延温度が３００℃未満においてはその加工が難しくなる。したがって、最終圧延温度は３００〜５５０℃、好ましくは３５０〜５５０℃、より好ましくは３９０〜５５０℃にしている。
【００３６】
また、圧延温度の調整は、図２で説明した熱間圧延加工装置３６において冷却水の温度、冷却水の量を調整したり、図２で説明した鋳造機３０において鋳造速度等を調整することで行う。
【００３７】
洗浄・巻取り工程（Ｆ４）は、圧延材を洗浄し巻き取って荒引線にする工程である。巻き取った荒引線の線径φは、例えば、８〜３０ｍｍとなるようにしている。
【００３８】
銅荒引線の線径φが８ｍｍより小さくなると、最終製品である銅線までの冷間加工度が小さくなり、十分な強度が得られない場合がある。また、線径φが３０ｍｍより大きくなると、銅荒引線の巻取りが難しくなる場合がある。したがって、銅荒引線の線径φが８〜３０ｍｍとなるように熱間圧延加工を多段に施すようにしている。
【００３９】
冷間加工工程（Ｆ５）は、巻き取った銅荒引線を送り出し、その銅荒引線に、常温下にて任意の加工度で冷間加工を施して、用途に応じた銅線にする工程である。
【００４０】
以上説明した本発明に係る銅荒引線の製造方法を用いれば、軟化温度を低下させた（低温で軟化しやすい、あるいは軟化特性に優れた）銅荒引線および銅線を製造できる。特に、後述する実施例で明らかになるように、半軟化温度が１７０℃以下の銅線を製造できる。
【００４１】
このように、本発明に係る銅荒引線の製造方法は、不純物元素を含んだ銅の溶湯を高温で鋳造（鋳造温度が１１００〜１２００℃）し、その銅鋳塊に低温圧延加工（最終圧延温度が３００〜５５０℃）を施しているので、熱間圧延加工中に不純物元素の銅への固溶限がさらに小さくなり、不純物元素の析出（固溶量の減少）がより促進されて進行することになる。これにより、軟化温度を低下させた銅荒引線が製造できる。さらに、その銅荒引線に冷間加工を施すと、軟化温度を低下させた銅線も製造できる。
【００４２】
また、本発明に係る製造方法は、既存あるいは慣用の製造コストが低い連続鋳造圧延設備や冷間加工装置を改造することなくそのまま使用できるので、軟化温度を低下させた銅荒引線および銅線を低コストで製造できる。
【００４３】
銅母材に不純物元素（Ｓ，Ｐｂ，Ｂｉ，Ｓｅ，Ｔｅ）が比較的多く含有している場合においても、最終圧延を不純物元素の銅への固溶限が小さくなる温度で行っているので、軟化温度が低い銅荒引線および銅線を製造できる。
【００４４】
【実施例】
本発明の効果を検証するために、図２で説明した連続鋳造圧延設備２１と冷間加工装置を用いて、銅母材の酸素含有量と、不純物元素の含有量と、最終圧延温度とを様々に変えて銅荒引線および銅線を作製し、銅線の半軟化温度を求めた。
【００４５】
いずれの試料についても、銅母材の酸素含有量を２００〜４００ｍａｓｓｐｐｍとし、その銅母材が含有するＳ，Ｐｂ，Ｂｉの総含有量を５〜２０ｍａｓｓｐｐｍとし、鋳造温度を１１５０±１０℃とし、銅荒引線の線径を８ｍｍとし、銅線の線径を２．６ｍｍとした。各銅線試料には、油浴および塩浴中にて常温〜４００℃の種々の温度でそれぞれ１時間加熱した後、引張試験を行い、それぞれの引張強度を測定した。この引張強度から各銅線試料の等時軟化曲線を得た。各銅線試料の軟化特性の評価は、等時軟化曲線から求めた半軟化温度（「常温の引張強度」と「完全軟化時の引張強度」の中間の引張強度を示す加熱温度）により行った。各銅線試料の引張試験自体は従来と同じ要領で実施したため、詳細な説明は省略する。
【００４６】
（実施例１〜１０）
実施例１〜１０は、最終圧延を３９０〜５５０℃の圧延温度で行って銅荒引線および銅線を製造したものである。
【００４７】
（比較例１〜１０）
比較例１〜１０は、最終圧延を５５０℃よりも高い圧延温度で行って銅荒引線および銅線を製造したものである。
【００４８】
これら実施例１〜１０および比較例１〜１０について、各銅線試料の軟化特性の評価結果を表１に示す。表１中のＳｎ，Ｆｅ，Ｎｉは不可避不純物である。
【００４９】
【表１】

【００５０】
表１に示すように、実施例１〜１０は、銅荒引線製造時の最終圧延温度が３９０〜５５０℃なので、加熱処理時の軟化がより促進され、銅線の半軟化温度が１７０℃以下と低くなっていることがわかる。
【００５１】
これに対して比較例１〜１０は、銅荒引線製造時の最終圧延温度が５５０℃よりも高いので、最終圧延温度が高くなるにつれて銅線の半軟化温度が高くなる傾向にあり、いずれも銅線の半軟化温度が１７０℃よりも高くなっている。
【００５２】
特に、実施例１〜１０の銅線の半軟化温度は、組成のほぼ等しい比較例１〜１０の銅線の軟化温度よりも低いことがわかる。（例えば、実施例１（１５１℃）と比較例１（１７１℃）、実施例５（１５０℃）と比較例４（１８２℃）など）。よって実施例１〜１０は、比較例１〜１０に比べて銅線の軟化温度が低下し、軟化しやすいことが明らかとなった。
【００５３】
したがって、銅母材の不純物元素の含有量を所定範囲に調整した銅の溶湯から１１００〜１２００℃の高い鋳造温度で銅鋳塊を製造し、これを多段に圧延し、３００〜５５０℃の低い最終圧延温度で銅荒引線を製造し、さらにこれを冷間伸線して銅線を製造すれば、銅荒引線および銅線の軟化温度を低下できることがわかる。
【００５４】
上記実施例では、銅母材にＳ，Ｐｂ，Ｂｉが含有している例で説明したが、銅母材に、Ｓ，Ｐｂ，Ｂｉの他にＳｅ，Ｔｅを含めた五種の元素のうち一種以上を含有していても同様の効果が得られる。
【００５５】
また、本発明は銅に関するものであるが、例えば、アルミニウム合金、鉄合金などの他金属に応用することも可能である。
【００５６】
【発明の効果】
以上説明したことから明らかなように、本発明によれば、次のような優れた効果を発揮する。
【００５７】
（１）不純物元素を含む銅の溶湯から１１００〜１２００℃の高い鋳造温度で銅鋳塊を製造し、これを多段に圧延し、３００〜５５０℃の低い最終圧延温度で銅荒引線を製造し、さらにこれを冷間伸線して銅線を製造しているので、銅荒引線および銅線の軟化温度を低下させることができる。
【００５８】
（２）銅荒引線および銅線の製造設備の改造を必要としないことから、この種の線材製品のコストを維持しつつ、性能向上を図ることが可能となる。
【００５９】
（３）銅母材に不純物元素が比較的多く含まれる場合においても、最終圧延を不純物元素の銅への固溶限が小さくなる温度で行っているので、軟化温度が低い銅荒引線および銅線を製造できる。
【００６０】
（４）銅基材料のリサイクル技術も向上させることができ、環境問題に対しても非常に大きく貢献できる。
【図面の簡単な説明】
【図１】本発明の好適実施の形態を示すフローチャートである。
【図２】連続鋳造圧延設備の一例を示す概略図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a copper rough drawn wire by continuous casting and rolling, and a copper wire obtained by cold working the copper rough drawn wire produced thereby.
[0002]
[Prior art]
A copper wire widely used as a conductive material for various uses is generally processed into a desired size by cold drawing (drawing) a rough copper wire. Conventionally, as a method for producing the copper rough drawn wire, a continuous casting and rolling method has been the mainstream in terms of productivity, yield, and the like. For example, methods such as the Contirod method, the SCR method, and the Properzi method have become widely known. I have.
[0003]
As an example of the continuous casting and rolling equipment, there is a Conirod type horizontal (horizontal) continuous casting and rolling equipment 21 as shown in FIG. The equipment 21 is provided with a shaft furnace 24 for converting an electrolytic copper plate 22 serving as a copper base material into a molten metal 23, a casting gutter 25 for guiding the molten metal 23 downstream, and provided in the middle of the casting gutter 25 to maintain the temperature of the molten metal 23. A holding furnace 26, a nozzle 27 for guiding the molten metal 23 in the casting gutter 25 downward, a tundish 28 for guiding the molten metal 23 from the nozzle 27 downstream, and a molten metal 23 from the tundish 28 are continuously cast into a copper ingot 29. A horizontal twin belt caster 30 and a copper ingot 29 are rolled in multiple stages by rolling rolls 31 and 32 to form a copper hot rolled material 33, and the rolled material 33 is finally rolled by a most downstream rolling roll 34. And a hot rolling device 36 for converting the copper wire into a rough drawn wire 35.
[0004]
In this equipment 21, first, the electrolytic copper plate 22 is melted in a shaft furnace 24 to form a melt 23, and the melt 23 is sent from a nozzle 27 to a tundish 28 via a casting gutter 25 and a holding furnace 26. Then, the molten metal 23 is continuously poured into the casting machine 30, and becomes a copper ingot 29 by the casting machine 30. The copper ingot 29 is hot-rolled step by step by the rolling rolls 31 and 32 of the device 36 to become a rolled material 33. When the rolled material 33 is finally rolled by the rolling rolls 34, a copper rough wire 35 having a desired diameter is obtained. When the copper rough wire 35 is subjected to cold drawing, a copper wire as a conductive wire for various uses can be obtained.
[0005]
In the cold drawing, the softening property of copper, that is, the softening temperature of copper, is mentioned as an extremely important property from an industrial viewpoint. For example, when an annealed copper wire is to be manufactured from the copper rough drawn wire 35, it is required that the annealed copper wire be as soft as possible in view of its flexibility. Also, in the case of manufacturing a hard copper wire from the copper rough drawn wire 35, it is indispensable to sufficiently soften the work material in the intermediate annealing step.
[0006]
The softening characteristics of copper vary greatly depending on its purity (the type and amount of the contained impurity element or inevitable impurity), the production method, the processing history, and the like. Therefore, in recent years, in order to obtain a copper rough drawn wire and a copper wire which are more easily softened, vigorous studies have been made on the effects of the contained impurity elements and the processing history on the softening temperature. It is known that copper is likely to soften as the solid solution amount of the contained impurity element decreases and as the degree of cold working increases.
[0007]
Prior art document information related to the invention of this application includes the following.
[0008]
[Patent Document 1]
JP-A-6-240426
[Problems to be solved by the invention]
However, for the purpose of lowering the softening temperature, it is very difficult to remove a trace amount of impurity element dissolved in the molten metal 23 by the continuous casting and rolling facility 21 described above.
[0010]
Further, in the case where the degree of cold work is increased to lower the softening temperature, it is necessary to increase the size of the copper rough drawn wire. In this case, the remodeling of the equipment 21 is indispensable, and the labor, man-hours, and remodeling costs associated therewith are incurred, and as a result, there is a problem that the cost of the product must be increased.
[0011]
The method for manufacturing a high-strength copper alloy trolley wire described in Patent Literature 1 is to finish-roll a rolled copper alloy containing 0.4 to 0.7% by weight of Sn at a temperature of 500 ° C. or less. This is a method of obtaining a rough line. Here, the finish rolling is performed in consideration of (1) that the strength becomes insufficient when the finish rolling temperature exceeds 500 ° C. and (2) that the decrease in conductivity due to Sn is suppressed when the finish rolling is performed at a low temperature. The temperature is set to 500 ° C. or less. Therefore, reduction of the softening temperature of the rough wire and the trolley wire is not considered.
[0012]
Accordingly, an object of the present invention is to provide a method for manufacturing a copper rough drawn wire having a reduced softening temperature without changing the manufacturing equipment, and a copper wire.
[0013]
[Means for Solving the Problems]
The present invention has been made in order to achieve the above-mentioned object, and a casting process is performed on a molten copper containing an impurity element to form a copper ingot, and the copper ingot is subjected to hot rolling in multiple stages to form a copper ingot. In the method of manufacturing a rough drawn wire, a method of manufacturing a copper rough drawn wire in which the casting process is performed at a casting temperature of 1100 ° C or more and 1200 ° C or less, and the final rolling of the hot rolling is performed at a rolling temperature of 300 ° C or more and 550 ° C or less. It is.
[0014]
The invention according to claim 2 is the method for producing a rough copper wire according to claim 1, wherein the molten metal is molten copper having an oxygen content of 600 mass ppm or less and containing an impurity element of 3 mass ppm or more and 200 mass ppm or less. is there.
[0015]
Here, the impurity element includes one or more of sulfur, lead, bismuth, selenium, and tellurium.
[0016]
The invention according to claim 3 is the method for producing a copper rough drawn wire according to

claim

1 or 2, wherein the copper ingot is subjected to hot rolling in multiple stages so that the wire diameter of the copper rough drawn wire is 8 to 30 mm. It is.
[0017]
According to a fourth aspect of the present invention, there is provided a copper wire produced by performing cold working on a copper rough drawn wire produced by the production method according to any one of the first to third aspects.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[0019]
FIG. 1 is a flowchart showing steps of a method for manufacturing a rough copper wire according to a preferred embodiment of the present invention.
[0020]
As shown in FIG. 1, the method of manufacturing a copper rough drawn wire according to the present invention includes a melting step (F1) of melting a copper base material into a molten copper (molten copper) containing an impurity element, and the molten copper. (F2), a hot rolling step (F3) of subjecting the copper ingot to multiple steps of hot rolling to form a rolled material, and washing and rolling the rolled material. And a washing / winding step (F4) for taking out the copper rough wire. Further, the next step (F5) is a cold (drawing) processing step in which the wound copper rough wire is sent out, and the copper rough wire is subjected to cold working to form a copper wire which is a conductive wire for various uses. is there.
[0021]
From the melting step (F1) to the washing / winding step (F4), existing or conventional continuous casting and rolling equipment, for example, the horizontal (horizontal) continuous casting and rolling equipment 21 of the Conirod type described in FIG. 2 is used. The cold working step (F5) is performed using an existing or common cold working apparatus.
[0022]
If FIG. 1 corresponds to FIG. 2, the melting step (F1) corresponds to the step in the shaft furnace 24 in FIG. 2, the casting step (F2) corresponds to the step in the casting machine 30 in FIG. 2, and the hot rolling step (F3). 2 corresponds to a step in the hot rolling apparatus 36 in FIG. 2, and the washing / winding step (F4) corresponds to a step between the rolling roll 34 and the copper rough wire 35 in FIG. 2.
[0023]
Each step will be described in more detail. The dissolving step (F1) is a step of dissolving copper into molten copper. The molten copper has an oxygen content of 600 mass ppm or less, and contains sulfur (S), lead (Pb), bismuth (Bi). , Selenium (Se), and tellurium (Te) are contained in total (total content) of 3 to 200 mass ppm of impurity elements containing one or more elements.
[0024]
Oxygen in copper exists mainly in the form of Cu ₂ O (cuprous oxide). At the time of cold drawing of a tough pitch copper wire (oxygen content: 200 to 500 mass ppm), tension is applied in the longitudinal direction and the cuprous oxide itself breaks or the boundary between the cuprous oxide and the copper matrix separates, resulting in voids (voids). (See, for example, Hiroshi Tanaka and Kazuya Yoshida, "Material Properties and Cupping Defects of Tough Pitch Copper", Journal of the Japan Society for Technology of Plasticity, 1982, Vol. 24, p. 470.) And, since the voids unite and develop as the wire drawing proceeds, it is considered that disconnection is likely to occur when the oxygen concentration in copper is high (when the amount of Cu ₂ O is large).
[0025]
Therefore, the oxygen content in the molten copper is set to 600 mass ppm or less, more preferably, 200 to 400 mass ppm as described later in Examples.
[0026]
S, Pb, Bi, Se, and Te are also impurity elements or unavoidable impurities contained in copper in a relatively large amount, and when they are dissolved in copper, all of them extremely increase the softening temperature of copper in a very small amount ( For example, Hisashi Suzuki, Mikihiro Sugano, Takao Maeda, Shinsuke Yamazaki, "Effects of Addition of a Small Amount of Group b and Transition Metal Elements on Softening Properties and Conductivity of Pure Copper Worked Materials", Journal of Copper and Brazing Technology, 1984, 23rd Pp. 25-35, and Masayoshi Aoyama and Mikihiro Sugano, "Effects of Pb, S, and O Additions on Softening Properties of Pure Copper Worked Material", Journal of Copper and Brazing Technology, 1996, Vol. 35, p. 110-117).
[0027]
However, these five elements have the feature that the solid solubility limit in copper is extremely small (for example, RP Elliott: Constitution of Binary Alloys, First Supplement (1985), p. 381, and M. Hansen, K. Anderuko: Constitution of Binary Alloys, (1958), pp. 308-309, 609-612, 628-629, 638-641).
[0028]
In the present embodiment, as described later, since the final rolling is performed at a low rolling temperature of 300 ° C. or more and 550 ° C. or less, the solubility limit of these elements in copper during hot rolling is further reduced, Element precipitation (reduction in the amount of solid solution) is further accelerated and proceeds. Therefore, the softening temperature of the copper rough drawn wire and the copper wire can be reduced.
[0029]
Further, as other effects, promotion of compound formation and precipitation due to coexistence of these five elements and other trace elements are also expected.
[0030]
It is very difficult to adjust the total content of impurity elements including one or more of S, Pb, Bi, Se, and Te to less than 3 mass ppm. When the content is less than 3 mass ppm, no problem such as a decrease in the conductivity or surface quality of the copper rough drawn wire and the copper wire is recognized even under the conventional manufacturing conditions, and the influence on the softening temperature of the copper rough drawn wire and the copper wire is small. . On the other hand, when the total content of impurity elements containing one or more of S, Pb, Bi, Se, and Te exceeds 200 mass ppm, the softening temperature of the copper rough drawn wire and the copper wire becomes excessive even if the manufacturing conditions are changed. In addition to the above, the copper rough wire and the copper wire may have lower conductivity and lower surface quality.
[0031]
Therefore, the total content of impurity elements containing one or more of S, Pb, Bi, Se, and Te in the molten copper is 3 to 200 mass ppm, preferably 3 to 100 mass ppm, and more preferably 3 to 50 mass ppm. ppm, particularly preferably 3 to 25 mass ppm.
[0032]
The casting step (F2) is a step of casting a molten copper at a casting temperature of 1100 to 1200 ° C to form a copper ingot.
[0033]
If the temperature of the molten metal is low, the fluidity of the molten metal is lowered, which may make the operation difficult. Also, when the temperature of the molten metal increases, the surface quality of the copper rough drawn wire and the copper wire tends to decrease due to an increase in the amount of absorbed hydrogen gas and an increase in the amount of voids (blow holes and pin holes) in the copper ingot. . Therefore, the casting temperature is set to 1100 to 1200 ° C.
[0034]
In the hot rolling step (F3), the copper ingot is subjected to hot rolling at a rolling temperature of 600 to 900 ° C. in the initial stage of rolling, and is subjected to hot working at a rolling temperature of 300 to 550 ° C. in the final rolling. This is the process of making the material.
[0035]
In order to lower the softening temperature of the copper rough drawn wire and the copper wire, it is necessary to reduce the solid capacities of the above five elements. For this purpose, the upper limit of the final rolling temperature is set to a temperature at which the solid solubility limits of the five elements become small, that is, 550 ° C. or lower. On the other hand, when the rolling temperature is lowered, the hot workability of copper is reduced, so that when the final rolling temperature is lower than 300 ° C., the working becomes difficult. Therefore, the final rolling temperature is 300 to 550 ° C, preferably 350 to 550 ° C, and more preferably 390 to 550 ° C.
[0036]
In addition, the adjustment of the rolling temperature is performed by adjusting the temperature of the cooling water and the amount of the cooling water in the hot rolling apparatus 36 described in FIG. 2, or adjusting the casting speed and the like in the casting machine 30 described in FIG. 2. Do with.
[0037]
The washing / winding step (F4) is a step of washing and rolling the rolled material to make a rough drawing. The wire diameter φ of the wound rough drawn wire is, for example, 8 to 30 mm.
[0038]
When the wire diameter φ of the copper rough drawn wire is smaller than 8 mm, the degree of cold working to the copper wire as the final product becomes small, and sufficient strength may not be obtained. When the wire diameter φ is larger than 30 mm, it may be difficult to wind the copper rough drawn wire. Therefore, hot rolling is performed in multiple stages so that the wire diameter φ of the copper rough drawn wire is 8 to 30 mm.
[0039]
The cold working step (F5) is a step in which the wound copper rough wire is sent out, and the copper rough wire is subjected to cold working at an arbitrary working degree at room temperature to obtain a copper wire according to the application. is there.
[0040]
By using the method of manufacturing a copper rough drawn wire according to the present invention described above, a copper rough drawn wire and a copper wire whose softening temperature is lowered (softening easily at a low temperature or excellent in softening characteristics) can be manufactured. In particular, a copper wire having a half-softening temperature of 170 ° C. or less can be manufactured, as will be apparent from examples described later.
[0041]
As described above, according to the method for producing a copper rough drawn wire according to the present invention, a molten copper containing an impurity element is cast at a high temperature (casting temperature is 1100 to 1200 ° C.), and the copper ingot is subjected to low-temperature rolling (final rolling). (At a temperature of 300 to 550 ° C.), the solid solubility limit of the impurity element in copper is further reduced during hot rolling, and the precipitation of the impurity element (reduction in the amount of solid solution) is further promoted and progresses. Will do. Thus, a copper rough drawn wire having a lowered softening temperature can be manufactured. Further, when the copper rough wire is subjected to cold working, a copper wire having a lowered softening temperature can also be manufactured.
[0042]
Further, the production method according to the present invention can be used as it is without modifying existing or conventional production costs of continuous casting and rolling equipment and cold working equipment, so that copper rough drawn wires and copper wires with reduced softening temperatures can be used. Can be manufactured at low cost.
[0043]
Even when the copper base material contains a relatively large amount of impurity elements (S, Pb, Bi, Se, Te), the final rolling is performed at a temperature at which the solubility limit of the impurity elements in copper is reduced. A copper rough wire having a low softening temperature and a copper wire can be manufactured.
[0044]
【Example】
In order to verify the effect of the present invention, the oxygen content of the copper base material, the content of the impurity element, and the final rolling temperature were determined using the continuous casting and rolling equipment 21 and the cold working apparatus described in FIG. A copper rough wire and a copper wire were prepared in various ways, and the half-softening temperature of the copper wire was determined.
[0045]
For each of the samples, the oxygen content of the copper base material was set to 200 to 400 mass ppm, the total content of S, Pb, and Bi contained in the copper base material was set to 5 to 20 mass ppm, and the casting temperature was set to 1150 ± 10 ° C. The wire diameter of the copper rough wire was 8 mm, and the wire diameter of the copper wire was 2.6 mm. Each copper wire sample was heated at various temperatures from room temperature to 400 ° C. for 1 hour in an oil bath and a salt bath, and then subjected to a tensile test to measure the tensile strength of each. An isochronous softening curve of each copper wire sample was obtained from the tensile strength. The evaluation of the softening characteristics of each copper wire sample was performed based on the half-softening temperature (heating temperature indicating an intermediate tensile strength between “normal temperature tensile strength” and “completely softened tensile strength”) obtained from the isochronous softening curve. . Since the tensile test itself of each copper wire sample was performed in the same manner as in the prior art, detailed description is omitted.
[0046]
(Examples 1 to 10)
In Examples 1 to 10, the final rolling was performed at a rolling temperature of 390 to 550 ° C. to produce a copper rough drawn wire and a copper wire.
[0047]
(Comparative Examples 1 to 10)
In Comparative Examples 1 to 10, the final rolling was performed at a rolling temperature higher than 550 ° C. to produce a copper rough drawn wire and a copper wire.
[0048]
Table 1 shows the evaluation results of the softening characteristics of the copper wire samples for Examples 1 to 10 and Comparative Examples 1 to 10. Sn, Fe, and Ni in Table 1 are unavoidable impurities.
[0049]
[Table 1]

[0050]
As shown in Table 1, in Examples 1 to 10, since the final rolling temperature during the production of copper rough drawn wire is 390 to 550 ° C, softening during heat treatment is further promoted, and the semi-softening temperature of the copper wire is 170 ° C or less. It turns out that it is low.
[0051]
On the other hand, in Comparative Examples 1 to 10, since the final rolling temperature at the time of producing the copper rough drawn wire is higher than 550 ° C., the semi-softening temperature of the copper wire tends to increase as the final rolling temperature increases. The semi-softening temperature of the copper wire is higher than 170 ° C.
[0052]
In particular, it can be seen that the semi-softening temperatures of the copper wires of Examples 1 to 10 are lower than the softening temperatures of the copper wires of Comparative Examples 1 to 10 having substantially the same composition. (For example, Example 1 (151 ° C.) and Comparative Example 1 (171 ° C.), Example 5 (150 ° C.) and Comparative Example 4 (182 ° C.)). Therefore, it became clear that the softening temperature of the copper wire of Examples 1 to 10 was lower than that of Comparative Examples 1 to 10, and the copper wire was easily softened.
[0053]
Therefore, a copper ingot is produced at a high casting temperature of 1100 to 1200 ° C. from a molten copper of which the content of the impurity element in the copper base material is adjusted to a predetermined range, and this is rolled in multiple stages, and a low temperature of 300 to 550 ° C. It can be seen that if a copper rough wire is manufactured at the final rolling temperature and then the copper wire is cold drawn to manufacture a copper wire, the softening temperature of the copper rough wire and the copper wire can be lowered.
[0054]
In the above embodiment, an example was described in which S, Pb, and Bi were contained in the copper base material. However, among the five elements including Se and Te in addition to S, Pb, and Bi in the copper base material, The same effect can be obtained even if one or more kinds are contained.
[0055]
Although the present invention relates to copper, the present invention can be applied to other metals such as an aluminum alloy and an iron alloy.
[0056]
【The invention's effect】
As is clear from the above description, the present invention exerts the following excellent effects.
[0057]
(1) A copper ingot is manufactured from a molten copper containing an impurity element at a high casting temperature of 1100 to 1200 ° C, and is rolled in multiple stages, and a rough copper wire is manufactured at a low final rolling temperature of 300 to 550 ° C. Further, since the copper wire is manufactured by cold drawing the copper wire, the softening temperature of the copper rough drawn wire and the copper wire can be lowered.
[0058]
(2) Since it is not necessary to modify the copper roughing wire and the copper wire manufacturing equipment, it is possible to improve the performance while maintaining the cost of this kind of wire material.
[0059]
(3) Even when the copper base material contains a relatively large amount of an impurity element, the final rolling is performed at a temperature at which the solubility limit of the impurity element in copper is reduced, so that the copper rough drawn wire and the copper having a low softening temperature. Wire can be manufactured.
[0060]
(4) The technology for recycling copper-based materials can also be improved, and can greatly contribute to environmental issues.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a preferred embodiment of the present invention.
FIG. 2 is a schematic view showing an example of a continuous casting and rolling facility.

Claims

In a method for producing a copper ingot by subjecting a molten copper containing an impurity element to a casting process to form a copper ingot and subjecting the copper ingot to multiple stages of hot rolling to produce a copper rough drawn wire, A method for producing a rough copper wire, wherein the method is performed at the following casting temperature, and the final rolling of the hot rolling is performed at a rolling temperature of 300 ° C. or more and 550 ° C. or less.

The method for producing a copper rough drawn wire according to claim 1, wherein the molten metal is a molten copper having an oxygen content of 600 mass ppm or less and an impurity element contained in a range of 3 mass ppm to 200 mass ppm.

The method for producing a copper rough drawn wire according to claim 1 or 2, wherein the copper ingot is subjected to hot rolling in multiple stages so that the wire diameter of the copper rough drawn wire is 8 to 30 mm.

A copper wire produced by subjecting a rough copper wire produced by the production method according to claim 1 to cold working.