JP4615794B2

JP4615794B2 - Method for producing copper-based alloy plate for connector

Info

Publication number: JP4615794B2
Application number: JP2001297654A
Authority: JP
Inventors: 茂樹清峰; 秀昭小幡
Original assignee: 清峰金属工業株式会社
Priority date: 2001-09-27
Filing date: 2001-09-27
Publication date: 2011-01-19
Anticipated expiration: 2021-09-27
Also published as: JP2003105464A

Description

【０００１】
【発明の属する技術分野】
本発明は、近代産業の花形として、情報機器類特に、携帯電話やパソコンなどモバイル関連機器、電子部品、自動車、家電品、精密機械等に使用され、先端技術材料の王座を占めるに到った各種コネクターに重用される、新規な銅合金板に関する。具体的には本発明は、高強度、高バネ性と優れた曲げ加工性を有するコネクター用新規銅合金板及びその製造方法に関するものである。
【０００２】
【従来の技術】
コネクター用銅基合金板の従来技術の一般的水準は、凡そ次の通りである。例えば、電子機器装置の内部実装は、ＩＣ，ＬＳＹ，ＶＬＳＩへの急速な高集積化に伴って高密度化され、それに必要なコネクターやＩＣソケットもますます多機能化、及び高信頼性化が要求されている。また、車の電気配線もますます高密度化されており、軽量化の要求もあり、これに用いるコネクターも多機能化、高信頼性、小型化が進んでいる。現状の具体的技術では、ターミナルと電線の接続は、高密度化による電線本数の増加に対して、結線の合理化について、圧接が採用され、ターミナルに用いる材料は、強度、バネ性が大きいことが必要であると同時に複雑な加工にも耐える成型加工性も必要である。また、ＩＣソケットは集積度の向上により、ピン数が増加し、実装方式も変化しており、これを構成する材料も強度、高バネ性と共に更に高度の加工性が要求されている。そのため、前記のような用途のコネクター用材料としては、リン青銅や高機能リン青銅ペリリウム銅、チタン銅が用いられた。ところが、リン青銅は圧接型コネクターとして使用するには強度弾性が十分ではない。このためこの種の用途には、最近ペリリウム銅、チタン銅が使用されている。
【０００３】
コネクター用銅基合金板として多く用いられた材料としてはリン青銅特にＪＩＳ−Ｃ５２１０がある。その化学組成は重量％でＳｎ７〜９，Ｐ０．０３〜０．３５，Ｃｕと不可避的不純物の合計１００であるバネ用リン青銅（Ｃ５２１０）。リレースイッチなどのバネ性、曲げ加工性を要求される用途に高機能リン青銅（ＫＡ８２５と記した）が用いられている。その化学組成は重量％でＳｎ７．５〜８．５，Ｎｉ０．２〜０．３，Ｐ０．０３〜０．３５，Ｃｕと不可避的不純物の合計１００である。それらの曲げ加工性は、図２の曲線ＢＷ（ＢＷはＢａｄＷａｙを意味して試験片が圧延方向に平行である），ＧＷ（ＧＷはＧｏｏｄＷａｙを意味して試験片が圧延方向に直角である）に示すごとくであり、曲げ加工性を引張強さ（Ｎ／ｍｍ²）に対する許容曲げ半径（曲げ半径／板厚の比）で表した。この値が右下にあるほうが安全によく曲がることを意味している。換言すれば、この従来技術の材料はこれらの線から下のＲ／ｔ比で曲げれば、この材料は破壊することを意味している。例えば、その限界は、ＫＡ８２５でも引張強さが７００Ｎ／ｍｍ²で、Ｒ／ｔ比はＢＷで０．８，７５０Ｎ／ｍｍ²では２．０である。引張強さの限界はＫＡ８２５でＧＷの曲線で最高値９００Ｎ／ｍｍ²で表わされている。これ以上の強度は得られないことを意味している。高機能リン青銅ＫＡ８２５はバネ用リン青銅Ｃ５２１０に比較してＢＷ，ＧＷ曲線ともに右下に位置している。即ち、ＫＡ８２５はＣ５２１０に比べて高い強度と曲げ加工性を持っているといえる。
【０００４】
【発明が解決しようとする課題】
然し乍ら、これら従来技術のコネクター製品の性能では、最新の電子機器装置の内部実装に対しては、特に曲げ加工性の面で、機器の小型化のためには、十分ではない。即ち、前記のＲ／ｔの性能の限界が、機器の小型化のネックになるから、この水準のままでは、現在以上に電子機器類を超小型化することができない。従って、コネクター用材料の曲げ性能を従来よりも一段と向上させ、前記のＲ／ｔを更に小さくしても破壊しない材料を開発することが、本発明において解決すべき課題となるものである。更にこの課題を具体的に説明する。即ち、前記ベリリウム、チタン等を用いたものについては、ベリリウム銅、チタン銅はそれらの強度と弾性を持たせるためには、８００℃以上の高温度での溶体化処理と再結晶化熱処理が必要である。そのため、工程が高コストとなり、経済性の面で問題がある。更に、強度と弾性を持たせるためには、プレス成型加工後３００℃〜３５０℃で時効処理を行う場合もあるので、工程が複雑で高コストとなるから、やはり経済性の面で欠点がある。
【０００５】
前記のような諸問題を解決すべく本出願人は、先ず、古くから知られているリン青銅に少量のＮｉを添加したＣｕ−Ｓｎ−Ｎｉ−Ｐ系銅合金に着目して、１９９０年に、Ｓｎ８〜９％、Ｎｉ０．１〜０．３５％、Ｐが０．０３〜０．３５％、残部がＣｕ及び不可避的不純物からなる高機能リン青銅（ＫＡ８２５）を開発した。この合金の強化機構は、Ｃｕ中へのＳｎ及びＮｉの固溶強化とＮｉとＰの化合物の形成による分散強化及び冷間圧延による加工硬化の組合せによるものである。然し乍ら、この合金も前記最新の電子機器用コネクター用材料としては、十分ではなかった。従って、上述のように、部品の小型化に伴い、材料は高強度であり、かつ曲げ加工性も要求されるようになっているが、元来高い曲げ加工性を有する高機能リン青銅（ＫＡ８２５）の更なる強度の向上と曲げ加工性の飛躍的な向上が各方面から望まれている。そこで本発明は前記コネクター用銅基合金の諸問題点を解決改良して、画期的新規なる銅基合金を創始提供することをその課題とし目的とするものである。
【０００６】
【課題を解決するための手段】
本発明は前記目的を達成するため次の手段を開発した。即ち、曲げ加工性に優れ高強度銅基合金の新規な製造方法を提供するものである。その特徴は、化学組成が、Ｓｎ（スズ）９〜１１重量％，Ｎｉ（ニッケル）０．２０〜０．３０重量％，Ｐ（リン）０．１０〜０．３０重量％と、合計重量１００％の残部がＣｕ（銅）及び不可避的不純物とにより成るコネクター用銅基合金板の製造方法であって、
１）前記化学組成を有する鋳塊を連続鋳造によって得る工程、
２）前記鋳塊を６５０〜７５０℃の温度で５〜１５時間拡散焼純する工程、
３）前記拡散焼純した鋳塊を面削した後、６１〜８５％の率で初期圧延する工程、
４）得られた板材を３５０〜５００℃の温度で３〜１０時間中間焼純する工程、
５）得られた板材を６１〜８５％の率で中間圧延又は最終圧延する工程、
６）焼鈍及び冷間圧延を４）及び５）の条件で１〜３回繰返す工程、
７）得られた冷延材をプレス加工幅にスリット後、最終焼純として、再結晶が起こらないように３００〜５００℃で３０〜３００秒の時間で、２〜１０Ｋｇ／ｍｍ^２の張力を長手方向に加えながらテンションアニール処理（ＴＡ）を施すことにより、結晶粒度を３μｍ以下にし、かつスリット歪みを無くする工程、
の各工程を１）〜７）の順序で行うことを特徴とするコネクター用銅基合金板の製造方法であることである。
【０００７】
次に本発明の各成分及び製造条件の限定理由を述べる。ＳｎはＣｕの中への固溶硬化により強度が計れるものであり、連続鋳造した時、銅中の拡散速度が遅くて偏析を起こしている。そのため、６５０℃〜７５０℃の温度で拡散焼純を行うことで結晶の均一化を行う必要がある。ＳｎはＣｕ中への固溶硬化により強度、バネ特性を向上させるために添加するものであり、その含有量は本発明では特に９〜１１％である。９％未満では前述の効果が期待できず、曲げ加工性も悪い。
１１％を超えると加工工程で問題があり初期圧延で割れが生じるためである。
【０００８】
ＮｉはＣｕ中への固溶硬化と結晶微細化に効果があり、強度、バネ特性を向上させるために添加するものであり、ＮｉもＳｎと同じように、連続鋳造を行った時Ｃｕ中のＮｉの拡散速度が遅くて偏析を起す。Ｎｉの添加量は０．１０〜０．３０％であり、０．１％未満では前述の効果が期待できず、０．３０％を超えると異相を生じ加工性を著しく低下させ、３０％の初期圧延率でも割れが生じることと、その後の６０％を超える加工率で冷間圧延を行うことが困難である。
【０００９】
ＰはＣｕ中への固溶硬化と脱酸効果があり、Ｎｉと化合物を形成して、分散強化に効果がある。その添加量は０．１〜０．３％であり、０．１％未満では前述の効果が無い。０．３％を超えると、加工工程に問題があり、初期圧延で割れが発生する。
【００１０】
本発明合金は前記組成範囲の合金を連続鋳造した鋳塊の拡散焼純を６５０℃〜７５０℃で５〜１５時間行って冷間加工できるＮｉ．Ｐ及びＳｎが固溶した組織に変える。６５０℃未満では均一な組織に変えるには長時間かかる。７５０℃を超えると不活性ガス中に混在する水分、酸素分子の合金中への拡散が進み、面削量が増加する。
【００１１】
次いで連続鋳造、それにつずく拡散焼純で形成された表面偏析を取り除くため面削を行う。この場合通常０．５ｍｍ前後の面削を行う。
【００１２】
次いで、６１〜８５％の初期圧延を行う。６１％未満では圧延組織が均質化せず、引きついで行う焼純処理においても圧延組織が均質化できない。また、８５％を超えると加工硬化が進み割れが発生する。
【００１３】
次いで、３５０℃〜５００℃で３〜１０時間焼純を行う。３５０℃未満では均質組織を得るのに長時間がかかる。また、５００℃を超えると結晶粒の成長があり、最終焼純での製品の結晶粒度に影響を及ぼし、製品の曲げ加工性が低下する。
【００１４】
次いで、中間圧延を６１〜８５％の圧延率で行う。６１％未満では圧延組織が均質化せず続いて行う焼純で均一な焼純組織が得られない。８５％を超えると加工硬化が進み加工性を著しく低下させる。
【００１５】
次いで、３５０℃〜５００℃で３〜１０時間焼純を行う。範囲を限定する理由は前記と同じである。
【００１６】
次いで、最終圧延を６１〜８５％の圧延率で行う。最終圧延率は強度と曲げ性を決める支配的要因である。６１％未満では高い強度と曲げ性が得られない。８５％を越えると加工硬化が進み割れが発生する。
【００１７】
０．１５ｍｍ以下の厚み、３０ｍｍ以下の幅でプレス加工されるケースが多いためプレス幅にスリット後の均質、かつ平坦度の良好な製品が求められる。最後に最終低温焼純をスリット幅にスリット後３００℃〜５００℃で３０〜３００秒の時間で再結晶化が起らないように２〜１０Ｋｇｆ／ｍｍ²の張力を長手方向に加えながらテンションアニール処理を施す。これにより、バネ限界値の回復ができ、スリッター後の端部に生ずるスリット歪みのない結晶粒度３μ以下の均質、かつ平坦度の良好な製品を得ることができる。
【００１８】
（実施例）
表１の化学組成を有する鋳塊幅３１５ｍｍ、厚み１６ｍｍのインゴットを連続鋳造を行って得た。鋳造インゴットは６８０〜７００℃で１０時間Ｎ₂中で焼純した。表面偏析を取り除くため上下０．５ｍｍ面削した。１６ｍｍ厚みの板材を加工硬化で割れが発生しない条件で初期圧延を行った。
【００１９】
【表１】

【００２０】
前記の結果を表３に示した。６１〜８５％の圧延率で初期圧延のできる化学組成は本発明組成の範囲にあるＮｏ．１，２，３とＮｏ．４，５，６であった。Ｎｏ．７，８の組成は３０〜４０％が限度であった。Ｎｏ．１〜６の素板材を６１〜８５％の率で初期圧延をした。この圧延材をＮ₂／Ｈ₂の混合気流中で３５０℃から５００℃で３〜１０時間の中間焼純を行った。得られた板材の初期圧延を６１〜８５％の率で行った。得られた板材を前記と同様に中間焼純した。その後６１〜８５％の圧延率で中間圧延した。得られた板材を前記同様に焼純して前記と同様に最終圧延した。得られた板材を２８ｍｍ幅にスリット後３５０〜５００℃Ｎ2／Ｈ2混合気流中で３０〜３００秒間２〜１０Ｋｇｆ／ｍｍ²の張力を長手方向に加えてテンションアニーリング（ＴＡ）した。初期圧延以降の製造条件を表２に示した。
【００２１】
【表２】

【００２２】
【表３】

【００２３】
各試験材の引張強さ、ヤング率、導電率、バネ限界値、９０度Ｗ曲げ加工試験、結晶粒度の測定を行った。引張り強さ、導電率、バネ限界値の測定は、夫々ＪＩＳ−Ｚ−２２４１，ＪＩＳ−Ｈ−０５０５，ＪＩＳ−Ｈ−３１３０に準拠した。９０度Ｗ折り曲げ加工試験はＪＩＳ−Ｚ−２２４８に準拠し、中央部山表面の状況を調べ、割れ、シワの発生が無い許容曲げ半径（Ｒ／ｔ）で示した。結晶粒度はＪＩＳ−Ｈ−０５０１に準拠した。結果を表３に示した。本発明の合金は比較合金に比べて、はるかに高い強度、弾性、バネ性を持っている。導電率は１１％ＩＡＣＳを示した。結晶粒度が３μと小さい。そのため、例３から明らかなごとく許容曲げ半径の値が略同一引張強度を有する比較合金４と比べてはるかに低い値を示した。即ち、本発明合金は高強度、高弾性でありながら、曲げ加工性が良好である。表１のＮｏ．１合金と比較合金Ｎｏ．４合金の引張強度と許容曲げ半径（Ｒ／ｔ）の関係を図１に示した。本発明の合金が比較合金に比較して、はるかに曲げ加工性が優れていることがわかる。本発明の合金が高強度、高弾性でありながら曲げ加工性が良いのは、Ｓｎ、Ｎｉ，Ｐの最適添加量と高い率での加工硬化の組合せと高い加工のできる温度範囲の確立及びスリット後に行うテンションアニーリング条件の確立により結晶粒度を３μ以下に微細化し、しかもスリット歪みを無くした総合効果である。
【００２４】
【発明の効果】
１）従来、コネクター用銅基合金の主な構成成分中Ｓｎは９％未満であり、最終圧延率を６０％以上にしても、許容曲げ半径は大きく、最新の電子機器類の超小型化の製造に支障があったところ、本発明では、Ｓｎを９％以上に上げ、かつ最終圧延率も６１％以上としたので、許容曲げ半径が画期的に小さくなり、該機器の超小型化に適応できるようになったという顕著な効果を得た。
２）更に、本発明の効果を総合すると次の通りとなる。
本発明はＳｎ，Ｎｉ，Ｐを適用添加した銅基合金に対して、前記のような諸条件で適切な処理を行うことによって添加したＳｎの固溶硬化とＮｉ，Ｐの固溶硬化、結晶微細化効果により高強度、高弾性であり、かつ曲げ加工性の飛躍的な向上を達成したコネクター合金を製造することができ、電装部品の高密度化に充分対応できるコネクター材を安価に、かつ安全に提供するものである。また、本発明方法により製造された銅基合金は前記のように優れた特性を有しているので、超小型のスイッチ、リレー、スイッチ用バネ、端子にも使用可能となる大きな効果を有している。
【図面の簡単な説明】
【図１】本発明のコネクター用銅基合金の引張強さに対する許容曲げ半径を従来品の性能との比較において表わしたグラフである。
【図２】従来技術のコネクター用銅基合金の引張強さに対する許容曲げ半径を規格との関係において表わしたグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention is used as a flower pattern of modern industry in information equipment, especially mobile related devices such as mobile phones and personal computers, electronic parts, automobiles, home appliances, precision machinery, etc., and has reached the throne of advanced technology materials. The present invention relates to a novel copper alloy plate used for various connectors. Specifically, the present invention relates to a novel copper alloy plate for connectors having high strength, high spring property and excellent bending workability, and a method for producing the same.
[0002]
[Prior art]
The general level of prior art copper-based alloy plates for connectors is roughly as follows. For example, the internal mounting of electronic equipment is becoming more dense with rapid integration into ICs, LSYs, and VLSIs, and the necessary connectors and IC sockets are becoming increasingly multifunctional and highly reliable. It is requested. In addition, the electrical wiring of cars is becoming more and more dense and there is a demand for weight reduction, and the connectors used for this are becoming increasingly multifunctional, highly reliable, and downsized. In the current specific technology, the connection between the terminal and the electric wire increases the number of electric wires due to the higher density, whereas the pressure connection is adopted for the rationalization of the connection, and the material used for the terminal has high strength and springiness. At the same time, it requires moldability to withstand complex machining. Further, IC sockets have increased pin counts and mounting methods due to improved integration, and the materials constituting them are required to have higher workability as well as strength and high springiness. For this reason, phosphor bronze, highly functional phosphor bronze perillium copper, and titanium copper were used as the connector materials for the above-described applications. However, phosphor bronze has insufficient strength and elasticity for use as a pressure contact type connector. For this reason, peryllium copper and titanium copper have recently been used for this type of application.
[0003]
As a material often used as a copper base alloy plate for connectors, there is phosphor bronze, particularly JIS-C5210. Its chemical composition is phosphor bronze for springs (C5210), which is Sn7-9, P0.03-0.35, Cu and a total of 100 inevitable impurities in weight%. High-performance phosphor bronze (referred to as KA825) is used for applications that require springiness and bending workability such as relay switches. The chemical composition is Sn in the range of 7.5 to 8.5, Ni 0.2 to 0.3, P 0.03 to 0.35, Cu and a total of 100 inevitable impurities. The bending workability thereof is shown by the curves BW in FIG. 2 (BW means BadWay and the test piece is parallel to the rolling direction), GW (GW means GoodWay and the test piece is perpendicular to the rolling direction) The bending workability was expressed as an allowable bending radius (bending radius / plate thickness ratio) to tensile strength (N / mm ² ). If this value is in the lower right, it means that it turns safely and well. In other words, this prior art material means that if it is bent from these lines at a lower R / t ratio, the material will break. For example, the limit is a tensile strength of 700 N / mm ² even KA825, R / t ratio is 2.0 in 0.8,750N / mm ² in BW. The limit of tensile strength is KA825, which is represented by a maximum value of 900 N / mm ² in the GW curve. This means that no further strength can be obtained. The high-performance phosphor bronze KA825 is located at the lower right of both the BW and GW curves compared to the phosphor bronze C5210 for spring. That is, it can be said that KA825 has higher strength and bending workability than C5210.
[0004]
[Problems to be solved by the invention]
However, the performance of these prior art connector products is not sufficient for downsizing the equipment, especially in terms of bendability, for internal mounting of the latest electronic equipment. That is, since the limit of the R / t performance becomes a bottleneck for miniaturization of devices, electronic devices cannot be miniaturized more than the present level at this level. Therefore, it is a problem to be solved in the present invention to further improve the bending performance of the connector material than before and to develop a material that does not break even if the R / t is further reduced. Further, this problem will be specifically described. In other words, for those using beryllium, titanium, etc., beryllium copper and titanium copper require solution treatment and recrystallization heat treatment at a high temperature of 800 ° C. or higher in order to have their strength and elasticity. It is. Therefore, the process becomes expensive and there is a problem in terms of economy. Furthermore, in order to give strength and elasticity, an aging treatment may be performed at 300 ° C. to 350 ° C. after press molding, so the process is complicated and expensive, so there is also a drawback in terms of economy. .
[0005]
In order to solve the above problems, the present applicant first focused on a Cu-Sn-Ni-P-based copper alloy in which a small amount of Ni was added to phosphor bronze which has been known for a long time. , Sn 8 to 9%, Ni 0.1 to 0.35%, P 0.03 to 0.35%, the balance is Cu and unavoidable impurities bronze (KA825) has been developed. The strengthening mechanism of this alloy is due to a combination of solid solution strengthening of Sn and Ni in Cu, dispersion strengthening by forming a compound of Ni and P, and work hardening by cold rolling. However, this alloy is not sufficient as the latest material for connectors for electronic devices. Therefore, as described above, with the miniaturization of parts, the material is required to have high strength and bendability, but originally high-performance phosphor bronze (KA825) having high bendability. ) Is required from various directions for further improvement in strength and dramatic improvement in bending workability. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve and improve various problems of the copper base alloy for connectors and to provide and provide an innovative new copper base alloy.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has developed the following means. That is, the present invention provides a novel method for producing a high-strength copper-based alloy having excellent bending workability. The characteristics are that the chemical composition is Sn (tin) 9 to 11% by weight, Ni (nickel) 0.20 to 0.30% by weight, P (phosphorus) 0.10 to 0.30% by weight, and the total weight is 100. % Balance of Cu (copper) and a manufacturing method of a copper-based alloy plate for connectors comprising inevitable impurities ,
1) a step of obtaining an ingot having the chemical composition by continuous casting;
2 ) A step of diffusion-purifying the ingot at a temperature of 650 to 750 ° C. for 5 to 15 hours,
3 ) Step of initial rolling at a rate of 61 to 85% after chamfering the ingot that has been diffusion-refined .
4 ) A step of intermediately purifying the obtained plate material at a temperature of 350 to 500 ° C. for 3 to 10 hours,
5 ) A step of intermediate rolling or final rolling the obtained plate material at a rate of 61 to 85%,
6 ) A step of repeating annealing and cold rolling 1 to 3 times under the conditions of 4 ) and 5 ),
After slit 7) obtained cold rolled material to press working width, as a final ShoJun, at the time of 30 to 300 seconds to 300 to 500 ° C. as recrystallization does not occur, the tension of 2 to 10 kg / mm ² the tension-annealed (TA) the facilities Succoth while applying longitudinally, and the grain size in 3μm or less and eliminate the slit distortion step,
These steps are performed in the order of 1) to 7) , and this is a method for producing a copper-based alloy plate for connectors.
[0007]
Next, the reasons for limiting the components and production conditions of the present invention will be described. Sn can measure strength by solid solution hardening in Cu, and when continuously cast, the diffusion rate in copper is slow and segregation occurs. Therefore, it is necessary to make the crystals uniform by performing diffusion refractory at a temperature of 650 ° C. to 750 ° C. Sn is added in order to improve strength and spring characteristics by solid solution hardening in Cu, and its content is particularly 9 to 11% in the present invention. If it is less than 9%, the above-mentioned effects cannot be expected, and the bending workability is poor.
If it exceeds 11%, there is a problem in the processing step, and cracking occurs in the initial rolling.
[0008]
Ni is effective for solid solution hardening and crystal refining in Cu, and is added to improve strength and spring characteristics. Ni is also added to Cu in continuous casting as in the case of Sn. Ni diffusion rate is slow and segregation occurs. The amount of Ni added is 0.10 to 0.30%, and if it is less than 0.1%, the above-mentioned effects cannot be expected. If it exceeds 0.30%, a heterogeneous phase is produced, and the workability is remarkably reduced. It is difficult to cause cracking even at the initial rolling rate and to perform cold rolling at a processing rate exceeding 60% thereafter.
[0009]
P has a solid solution hardening in Cu and a deoxidizing effect, forms a compound with Ni, and has an effect of strengthening dispersion. The addition amount is 0.1 to 0.3%, and if it is less than 0.1%, the above-described effects are not obtained. If it exceeds 0.3%, there is a problem in the processing step, and cracking occurs in the initial rolling.
[0010]
The alloy of the present invention is Ni.I. which can be cold worked by performing diffusion sinter of an ingot obtained by continuously casting an alloy having the above composition range at 650 to 750 ° C. for 5 to 15 hours. Change to a solid solution of P and Sn. Below 650 ° C., it takes a long time to change to a uniform structure. If the temperature exceeds 750 ° C., the diffusion of moisture and oxygen molecules mixed in the inert gas into the alloy proceeds, and the amount of chamfering increases.
[0011]
Next, chamfering is carried out to remove surface segregation formed by continuous casting and subsequently diffusion sinter. In this case, chamfering of about 0.5 mm is usually performed.
[0012]
Next, 61 to 85% of initial rolling is performed. If it is less than 61%, the rolled structure will not be homogenized, and the rolled structure cannot be homogenized even in the tempering process performed. Moreover, when it exceeds 85%, work hardening will progress and a crack will generate | occur | produce.
[0013]
Subsequently, tempering is performed at 350 ° C. to 500 ° C. for 3 to 10 hours. Below 350 ° C., it takes a long time to obtain a homogeneous structure. Moreover, when it exceeds 500 degreeC, there exists a growth of a crystal grain, it affects the crystal grain size of the product in a final sinter, and the bending workability of a product falls.
[0014]
Next, intermediate rolling is performed at a rolling rate of 61 to 85%. If it is less than 61%, the rolled structure will not be homogenized and a uniform sinter structure will not be obtained in the subsequent sinter. When it exceeds 85%, work hardening progresses and workability is significantly reduced.
[0015]
Subsequently, tempering is performed at 350 ° C. to 500 ° C. for 3 to 10 hours. The reason for limiting the range is the same as described above.
[0016]
Next, the final rolling is performed at a rolling rate of 61 to 85%. The final rolling rate is the dominant factor that determines strength and bendability. If it is less than 61%, high strength and bendability cannot be obtained. If it exceeds 85%, work hardening proceeds and cracks occur.
[0017]
Since there are many cases in which press processing is performed with a thickness of 0.15 mm or less and a width of 30 mm or less, a product having a uniform and flatness after slitting is required for the press width. Finally, after the final low-temperature sintered product is slit to the slit width, tension annealing is performed while applying a tension of ² to 10 kgf / mm ^{2 in} the longitudinal direction so that recrystallization does not occur at 300 to 500 ° C. for 30 to 300 seconds. Apply processing. As a result, the spring limit value can be recovered, and a product having a uniform crystal grain size of 3 μm or less and having good flatness can be obtained without any slit distortion occurring at the end after slitting.
[0018]
(Example)
An ingot having an ingot width of 315 mm and a thickness of 16 mm having the chemical composition shown in Table 1 was obtained by continuous casting. The cast ingot was tempered in N ₂ at 680-700 ° C. for 10 hours. In order to remove surface segregation, top and bottom surfaces were cut by 0.5 mm. Initial rolling was performed on a plate material having a thickness of 16 mm under the condition that no cracks were generated by work hardening.
[0019]
[Table 1]

[0020]
The results are shown in Table 3. The chemical composition capable of initial rolling at a rolling rate of 61 to 85% is No. in the range of the composition of the present invention. 1, 2, 3 and No. 4, 5, and 6. No. The composition of 7,8 was limited to 30-40%. No. The base plate material of 1-6 was initially rolled at a rate of 61-85%. This rolled material was subjected to intermediate sinter for 3 to 10 hours at 350 to 500 ° C. in a mixed gas stream of N ₂ / H ₂ . The obtained plate material was initially rolled at a rate of 61 to 85%. The obtained plate material was subjected to intermediate smelting as described above. Thereafter, intermediate rolling was performed at a rolling rate of 61 to 85%. The obtained plate material was refined in the same manner as described above and finally rolled in the same manner as described above. The resulting plate material 28mm width and tension annealing (TA) tension of 30 to 300 seconds 2~10Kgf / mm ² at 350 to 500 ° C. N2 / H2 mixed gas stream from the slit in addition to the longitudinal direction. The production conditions after the initial rolling are shown in Table 2.
[0021]
[Table 2]

[0022]
[Table 3]

[0023]
The tensile strength, Young's modulus, electrical conductivity, spring limit value, 90 degree W bending test, and crystal grain size of each test material were measured. Measurements of tensile strength, electrical conductivity, and spring limit value were based on JIS-Z-2241, JIS-H-0505, and JIS-H-3130, respectively. The 90-degree W-bending test was conducted in accordance with JIS-Z-2248, and the condition of the surface of the central mountain was examined and indicated by an allowable bending radius (R / t) at which cracks and wrinkles did not occur. The crystal grain size conformed to JIS-H-0501. The results are shown in Table 3. The alloy of the present invention has much higher strength, elasticity and springiness than the comparative alloy. The conductivity was 11% IACS. The crystal grain size is as small as 3μ. Therefore, as apparent from Example 3, the value of the allowable bending radius was much lower than that of Comparative Alloy 4 having substantially the same tensile strength. That is, the alloy of the present invention has high strength and high elasticity, but has good bending workability. No. in Table 1 No. 1 alloy and comparative alloy no. The relationship between the tensile strength and the allowable bending radius (R / t) of the four alloys is shown in FIG. It can be seen that the alloy of the present invention has much better bending workability than the comparative alloy. The alloy of the present invention has high strength and high elasticity, but has good bending workability because of the combination of optimum addition amount of Sn, Ni, P and work hardening at a high rate, establishment of a temperature range capable of high work and slitting. This is a comprehensive effect that refines the crystal grain size to 3 μm or less by establishing tension annealing conditions to be performed later and eliminates slit distortion.
[0024]
【The invention's effect】
1) Conventionally, Sn is less than 9% in the main constituents of copper-based alloys for connectors, and even if the final rolling rate is 60% or more, the allowable bending radius is large, and the latest electronic devices can be miniaturized. In the present invention, when the production was hindered, Sn was increased to 9% or more and the final rolling ratio was set to 61% or more. Therefore, the allowable bending radius was remarkably reduced, and the apparatus was miniaturized. The remarkable effect of being able to adapt was obtained.
2) Further, the effects of the present invention are summarized as follows.
In the present invention, a solid solution hardening of Sn, a solid solution hardening of Ni, P, and a crystal formed by performing appropriate treatment under various conditions as described above on a copper base alloy to which Sn, Ni, P is added. It is possible to manufacture a connector alloy that has high strength and high elasticity due to the miniaturization effect, and has achieved a dramatic improvement in bending workability, and it is possible to produce a connector material that can sufficiently cope with the increase in the density of electrical components at low cost, and It is provided safely. Moreover, since the copper base alloy manufactured by the method of the present invention has excellent characteristics as described above, it has a great effect that it can be used for ultra-small switches, relays, switch springs, and terminals. ing.
[Brief description of the drawings]
FIG. 1 is a graph showing an allowable bending radius with respect to tensile strength of a copper base alloy for connectors according to the present invention in comparison with the performance of a conventional product.
FIG. 2 is a graph showing the allowable bending radius with respect to the tensile strength of a copper base alloy for a connector according to the prior art in relation to the standard.

Claims

The chemical composition is Sn (tin) 9 to 11% by weight, Ni (nickel) 0.20 to 0.30% by weight, P (phosphorus) 0.10 to 0.30% by weight, and the balance of the total weight 100% A method for producing a copper-based alloy plate for a connector comprising Cu (copper) and inevitable impurities ,
1) a step of obtaining an ingot having the chemical composition by continuous casting;
2 ) A step of diffusion-purifying the ingot at a temperature of 650 to 750 ° C. for 5 to 15 hours,
3) After scalped the diffusion ShoJun the ingot, the step of initially rolling at a rate of 61-85%,
4 ) A step of intermediately purifying the obtained plate material at a temperature of 350 to 500 ° C. for 3 to 10 hours,
5 ) A step of intermediate rolling or final rolling the obtained plate material at a rate of 61 to 85%,
6 ) A step of repeating annealing and cold rolling 1 to 3 times under the conditions of 4 ) and 5 ),
After slit 7) obtained cold rolled material to press working width, as a final ShoJun, at the time of 30 to 300 seconds to 300 to 500 ° C. as recrystallization does not occur, the tension of 2 to 10 kg / mm ² the tension-annealed (TA) the facilities Succoth while applying longitudinally, and the grain size in 3μm or less and eliminate the slit distortion step,
A process for producing a copper-based alloy plate for connectors , wherein the steps are performed in the order of 1) to 7) .