JP2009007625A - Method for producing high strength copper alloy for electric/electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a high strength copper alloy for electric/electronic components by which a dimensional change upon heating can be reduced without impairing its fundamental properties such as strength, electric conductivity and heat resistance. <P>SOLUTION: In the method for producing a high strength copper alloy for electric/electronic components, a copper base alloy containing, by mass, 1.0 to 4.0% Ni and 0.2 to 1.2% Si, and the balance Cu with inevitable impurities is cast, is rolled by hot rolling, is thereafter subjected to cold rolling at a working ratio of ≥15%, is subjected to aging treatment at 300 to 500°C for 30 min to 24 hr, is subsequently subjected to final cold rolling, and is further subjected to stress relieving annealing at 300 to 550°C for 30 s to 3 min, wherein the hardening rate of its hardness after the final cold rolling to its hardness after the aging treatment is controlled to ≤10%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、良好な強度および導電性を有するとともに、加熱時の寸法変化の小さい電気・電子部品用銅合金の製造方法に関する。   The present invention relates to a method for producing a copper alloy for electrical / electronic parts that has good strength and electrical conductivity and has a small dimensional change during heating.

リードフレーム、コネクタ等をはじめとした電気・電子部品用銅合金には高い強度と高い熱伝導率、更には電気・電子部品の製造工程中の加熱により軟化しにくい高い耐熱性が要求される。近年、電気・電子部品の小型化・高集積化が進むに連れ、上記特性への要求はますます厳しくなっており、これらの要求を満たす合金としてＣｕ−Ｎｉ−Ｓｉ系合金（コルソン合金）が開発され、各種添加元素を加えたものが使用されてきた。Ｃｕ−Ｎｉ−Ｓｉ系合金に関する特許はこれまで各社から多くの特許が公開されている。強度および電気伝導性を向上させるために成分や製造方法に言及した特許に関しては例えばオリン社の特許第２５７２０４２号が代表的である。曲げ加工性やめっき性に言及した特許に関しては例えば日鉱金属の特許第３３８３６１５号や特開昭５８−１２３８４６号、古河電工の特開平１０−１１０２２８号が挙げられる。ワイヤ・ボンディング性に言及した特許に関しては例えば日鉱金属の特許第２７１４５６０号や特公昭６２−４６０７１号が挙げられる。プレス性に言及した特許に関しては例えば日鉱金属の特許第３６１９５１６号や特開平１０−３０１５５号が挙げられる。
特許第２５７２０４２号公報 特許第３３８３６１５号公報 特開昭５８−１２３８４６号公報 特開平１０−１１０２２８号公報 特許第２７１４５６０号公報 特公昭６２−４６０７１号公報 特許第３６１９５１６号公報 特開平１０−３０１５５号公報 Copper alloys for electrical and electronic parts such as lead frames and connectors are required to have high strength and high thermal conductivity, as well as high heat resistance that is not easily softened by heating during the manufacturing process of electrical and electronic parts. In recent years, with the progress of miniaturization and high integration of electrical and electronic components, the requirements for the above characteristics have become more severe. As an alloy that satisfies these requirements, Cu-Ni-Si alloy (Corson alloy) is used. It has been developed and used with various additive elements added. Many patents relating to Cu-Ni-Si alloys have been published by various companies so far. For example, patent No. 2572204 from Olin is a typical example of a patent that mentions components and manufacturing methods in order to improve strength and electrical conductivity. Patents referring to bending workability and plating property include, for example, Japanese Patent No. 3383615, Japanese Patent Laid-Open No. 58-123846, and Japanese Patent Laid-Open No. 10-110228 by Furukawa Electric. Patents referring to wire bonding properties include, for example, Nikko Metal Patent No. 2714560 and Japanese Patent Publication No. Sho 62-46071. Patents referring to pressability include, for example, Nikko Mineral Patent No. 3619516 and JP-A-10-30155.
Japanese Patent No. 2572042 Japanese Patent No. 3383615 Japanese Patent Laid-Open No. 58-123846 Japanese Patent Laid-Open No. 10-110228 Japanese Patent No. 2714560 Japanese Examined Patent Publication No. 62-46071 Japanese Patent No. 3619516 Japanese Patent Laid-Open No. 10-30155

リードフレームは銅条をプレスやエッチングすることにより所定の形状を得るが、リードフレームが多ピン狭ピッチ化するに従い、寸法精度への要求も非常に厳しくなっている。プレスでの製造の場合、プレス後に５００℃程度のアニールを実施してプレス歪みを除去している。このため、リードフレーム用銅条は高い耐熱性と同時に、加熱での寸法変化が小さいことが強く要求されている。   The lead frame is obtained by pressing or etching a copper strip to obtain a predetermined shape. However, as the lead frame is narrowed by a multi-pin narrow pitch, the requirement for dimensional accuracy has become very strict. In the case of manufacturing by pressing, annealing at about 500 ° C. is performed after pressing to remove press distortion. For this reason, the copper strip for lead frames is strongly required to have a high heat resistance and a small dimensional change upon heating.

上述のようにＣｕ−Ｎｉ−Ｓｉ系合金の２次的特性に関しては多くの特許が見られる。しかし、加熱時の寸法変化に言及した特許は見られない。他の銅合金における加熱での寸法変化に関しては、Ｃｕ−Ｂｅ合金では時効熱処理過程において著しい寸法変化を生じることが知られており、多くの研究論文が見られる。例えば、三木らの「Ｃｕ−Ｂｅ合金の時効にともなう寸法変化（収縮および膨張）におよぼす冷間加工の影響」（銅と銅合金，３８（１９９９），１３９．）を初めとした一連の研究論文が挙げられる。しかし、Ｃｕ−Ｎｉ−Ｓｉ系合金においてはＣｕ−Ｂｅ合金の時効熱処理時のような顕著な寸法変化が見られないためか文献は見当たらない。リードフレームを製造する際は加熱時の寸法変化を見込んで製造条件が設定され、リードフレーム用銅合金条は寸法変化のばらつきが小さいことが要求される。従って、リードフレーム用銅合金条は製造条件の安定化により加熱時の寸法変化を安定化させるよう努力されてきたが、本質的に寸法変化を小さくする対策は充分とられてきたとはいえない。   As described above, there are many patents regarding secondary characteristics of Cu—Ni—Si based alloys. However, there are no patents referring to dimensional changes during heating. With regard to dimensional changes due to heating in other copper alloys, it is known that Cu-Be alloys cause significant dimensional changes during the aging heat treatment process, and many research papers are found. For example, a series of researches including Miki et al. “Effect of cold working on dimensional change (shrinkage and expansion) with aging of Cu—Be alloy” (copper and copper alloy, 38 (1999), 139.). A paper is mentioned. However, in the Cu—Ni—Si based alloy, there is no literature as to whether a significant dimensional change is observed as in the aging heat treatment of the Cu—Be alloy. When manufacturing a lead frame, manufacturing conditions are set in consideration of a dimensional change during heating, and the lead frame copper alloy strip is required to have a small variation in dimensional change. Accordingly, efforts have been made to stabilize the dimensional change during heating of the copper alloy strip for lead frames by stabilizing the manufacturing conditions, but it cannot be said that a measure for reducing the dimensional change has been taken sufficiently.

そこで、本発明は強度、導電率、耐熱性といった基本特性を損なうことなく、加熱時の寸法変化を小さくすることが可能な製造方法を提供することを目的とした。   Accordingly, an object of the present invention is to provide a manufacturing method capable of reducing a dimensional change during heating without impairing basic characteristics such as strength, conductivity, and heat resistance.

上記目的を達成するためにＣｕ−Ｎｉ−Ｓｉ系合金の時効処理条件や圧延条件が最終製品の加熱時の寸法変化に与える影響について調査した。この結果、最終圧延での硬化率が加熱による寸法変化に大きく影響しており、最終圧延による加工硬化量が多いほどその後の加熱により圧延方向に伸びることがわかった。従って、本来の強度、導電率、耐熱性といった基本特性を損なうことなく、加熱時の寸法変化を小さくするためには、時効処理条件と最終圧延加工率の適正化、および歪み除去焼鈍の適正化が必要であることを見出した。   In order to achieve the above object, the effects of aging treatment conditions and rolling conditions of Cu—Ni—Si based alloys on dimensional changes during heating of the final product were investigated. As a result, it was found that the curing rate in the final rolling greatly affects the dimensional change due to heating, and the greater the amount of work hardening by the final rolling, the longer the heating in the rolling direction. Therefore, in order to reduce the dimensional change during heating without impairing the basic properties such as the original strength, conductivity, and heat resistance, the aging treatment conditions and the final rolling process rate should be optimized, and the strain removal annealing should be optimized. Found that is necessary.

本発明は上記知見を基にして得られたものであり、Ｎｉを１．０質量％以上４．０質量％以下、Ｓｉを０．２質量％以上１．２質量％以下含有し、若しくはこれらに加えて副成分としてＰ、Ｚｎ、Ｓｎ、Ｍｇ、Ｆｅ、Ｃｏ、Ｍｎ、Ｚｒ、Ｔｉ、Ｃｒ、Ａｇのいずれか1種類以上を総量で２．０質量％未満含有し、残部がＣｕと不可避不純物からなる銅基合金を鋳造し、熱間圧延等により所望の厚みに圧延後、少なくとも１５％以上の加工率で冷間圧延を施し、３００℃以上５００℃以下の温度において３０分以上２４時間以下の時効処理を施し、その後最終冷間圧延を行い、更に３００℃以上５５０℃以下の温度で３０秒以上３分以下の歪み除去焼鈍を行う銅合金条の製造方法において、時効処理後の硬さに対する最終冷間圧延後の硬さの硬化率を１０％以下とすることにより、４００℃以上５５０℃以下の温度における１分以上１０分以下の加熱時の圧延方向への伸び率が５０ｐｐｍ以下であることを特徴とする加熱時の寸法変化の小さい電気・電子部品用高強度銅合金の製造方法であり、強度、導電率、耐熱性といった基本特性を損なうことなく、加熱時の寸法変化を小さくすることが可能な製造方法に関する。   The present invention has been obtained on the basis of the above knowledge, and contains 1.0 mass% to 4.0 mass% of Ni, 0.2 mass% to 1.2 mass% of Si, or these In addition to P, Zn, Sn, Mg, Fe, Co, Mn, Zr, Ti, Cr, and Ag as a subsidiary component, the total amount is less than 2.0% by mass, and the balance is inevitable with Cu. After casting a copper-based alloy made of impurities and rolling it to a desired thickness by hot rolling or the like, it is cold-rolled at a processing rate of at least 15% and at a temperature of 300 ° C. to 500 ° C. for 30 minutes to 24 hours In the method for producing a copper alloy strip, which is subjected to the following aging treatment, followed by final cold rolling, and further subjected to strain removal annealing at a temperature of 300 ° C. to 550 ° C. for 30 seconds to 3 minutes, Of hardness after final cold rolling to thickness Dimensional change during heating, characterized in that the elongation in the rolling direction during heating for 1 minute to 10 minutes at a temperature of 400 ° C. to 550 ° C. is 50 ppm or less by making the rate 10% or less The present invention relates to a method for producing a high-strength copper alloy for electrical / electronic parts having a small size and capable of reducing dimensional changes during heating without impairing basic properties such as strength, conductivity, and heat resistance.

本発明は強度、導電率、耐熱性といったＣｕ−Ｎｉ−Ｓｉ系合金の基本特性を損なうことなく、加熱時の寸法変化を小さくすることが可能な製造方法を開発したもので、リードフレームを製造する際のプレス歪み除去アニールの際の寸法変化の問題が解決された点において、その効果は非常に大きい。   The present invention has developed a manufacturing method that can reduce the dimensional change during heating without impairing the basic characteristics of Cu-Ni-Si alloys such as strength, conductivity, and heat resistance. The effect is very large in that the problem of the dimensional change during the press strain removal annealing is solved.

本発明に係る良好な強度および導電性を有するとともに、加熱時の寸法変化の小さい電気・電子部品用銅合金の製造方法について以下詳細に説明する。   A method for producing a copper alloy for electric / electronic parts having good strength and conductivity according to the present invention and having a small dimensional change during heating will be described in detail below.

（１）合金成分
合金成分はＮｉを１．０質量％以上４．０質量％以下、Ｓｉを０．２質量％以上１．２質量％以下とする。本合金では時効処理によってＣｕ中に金属間化合物であるＮｉ_２Ｓｉを析出させて高強度を得るが、Ｎｉが１．０質量％未満、若しくはＳｉが０．２質量％未満では充分な強度を得ることができない。一方、Ｎｉが４．０質量％、若しくはＳｉが１．２質量％を超えると導電率の低下、加工性の悪化が顕著になる。特に中間温度脆性が顕著になり、高温加熱時や熱間加工時の粒界割れが非常に起こり易くなる。また、Ｎｉ_２Ｓｉ等の析出量が多くなり、酸洗時にこれらが表面に残渣となってめっき不良を誘発する。更に、Ｎｉが４．０質量％を超えると溶解時に溶湯中に吸収されるＨの量が増大し、鋳塊中に固溶水素となって残存する。これらの水素は中間温度脆性の一因となり、冷間圧延後の焼鈍時に膨れ状の欠陥となりやすい。望ましくはＮｉが１．５質量％以上３．０質量％以下、Ｓｉが０．３質量％以上０．７質量％以下とする。ＮｉとＳｉの混合比は、金属間化合物であるＮｉ_２Ｓｉの組成に近い方が効率よく強度と導電率を向上させることが可能と考えられることから、Ｎｉ：Ｓｉ＝４：１とすることが望ましい。 (1) Alloy component The alloy component includes Ni of 1.0 mass% to 4.0 mass% and Si of 0.2 mass% to 1.2 mass%. While obtaining high strength by precipitating Ni 2 _Si which is an intermetallic compound in the Cu by aging treatment in this alloy, Ni is less than 1.0 wt%, or Si is a sufficient strength is less than 0.2 wt% Can't get. On the other hand, when Ni exceeds 4.0% by mass or Si exceeds 1.2% by mass, the decrease in conductivity and the deterioration of workability become remarkable. In particular, the intermediate temperature brittleness becomes remarkable and intergranular cracking at the time of high temperature heating or hot working is very likely to occur. In addition, the amount of precipitation of Ni ₂ Si and the like increases, and these become residues on the surface during pickling to induce plating defects. Further, when Ni exceeds 4.0% by mass, the amount of H absorbed in the molten metal at the time of melting increases, and remains as solute hydrogen in the ingot. These hydrogens contribute to brittleness at the intermediate temperature and are liable to become blistered defects during annealing after cold rolling. Desirably, Ni is 1.5 mass% or more and 3.0 mass% or less, and Si is 0.3 mass% or more and 0.7 mass% or less. The mixing ratio of Ni and Si should be Ni: Si = 4: 1 because it is considered possible to improve the strength and conductivity more efficiently when the composition is closer to the composition of Ni ₂ Si, which is an intermetallic compound. Is desirable.

合金成分は上記成分が基本であるが、更に副成分としてＰ、Ｚｎ、Ｓｎ、Ｍｇ、Ｆｅ、Ｃｏ、Ｍｎ、Ｚｒ、Ｔｉ、Ｃｒ、Ａｇのうちいずれか1種以上の成分を総量で２．０質量％未満含有しても本発明の効果は同様に得られるが、２．０質量％以上では導電率の低下等の特性劣化が大きくなる。   The alloy component is basically the above-mentioned component, but as a subsidiary component, any one or more of P, Zn, Sn, Mg, Fe, Co, Mn, Zr, Ti, Cr, and Ag are added in a total amount of 2. Even if the content is less than 0% by mass, the effects of the present invention can be obtained in the same manner.

Ｐは溶解時の脱酸剤としての効果とともに、若干の強度向上の効果がある。   P has an effect of slightly improving the strength as well as an effect as a deoxidizer during dissolution.

Ｚｎは半田濡れ性を向上させ、半田層との界面に生成するＣｕとＳｎの合金層の成長を抑制する作用がある。また、溶解時の脱ガス作用やＣｕのマイグレーションの抑制作用がある。比較的多量に添加しても特性への悪影響は少ないが、２．０質量％以上の添加では導電率の低下をもたらすとともに、効果も飽和する。   Zn improves solder wettability and has an effect of suppressing growth of an alloy layer of Cu and Sn generated at the interface with the solder layer. In addition, it has a degassing action at the time of dissolution and a Cu migration suppressing action. Even if added in a relatively large amount, there is little adverse effect on the properties, but addition of 2.0% by mass or more brings about a decrease in conductivity and saturation of the effect.

ＳｎはＣｕ中に固溶し、耐熱性とともにばね性、曲げ加工性、耐応力緩和特性を向上させる作用があり、コネクターとして使用する場合には添加することが望ましい。添加量が多くなると、導電率の低下をもたらすとともに、半田層との界面に生成するＣｕとＳｎの合金層の成長を助長し、またウィスカーを発生し易くなる。   Sn dissolves in Cu and has the effect of improving heat resistance, spring properties, bending workability, and stress relaxation resistance, and it is desirable to add Sn when used as a connector. Increasing the amount causes a decrease in conductivity, promotes the growth of an alloy layer of Cu and Sn formed at the interface with the solder layer, and tends to generate whiskers.

Ｍｇは導電率をそれほど低下させずに強度、耐熱性とともに耐応力緩和特性を向上させる効果がある。また、Ｓは中間温度脆性を助長させる元素であるが、ＭｇはＳと化合物を生成して粒界のＳを固定し、熱間加工性を向上させる効果がある。０．５質量％以上の添加では、酸化物の巻き込み等の鋳造性の低下をもたらす。   Mg has the effect of improving the stress relaxation resistance as well as the strength and heat resistance without significantly reducing the electrical conductivity. Further, S is an element that promotes brittleness at intermediate temperature, but Mg has an effect of generating a compound with S to fix S at the grain boundary and improving hot workability. Addition of 0.5% by mass or more results in deterioration of castability such as oxide entrainment.

Ｆｅは高温では主に固溶し、高温熱処理時の再結晶を遅らせ、結晶粒成長を抑制する作用がある。０．１質量％以上の添加では導電率の低下が大きいとともに、効果も飽和する。   Fe mainly dissolves at high temperatures, and has the effect of delaying recrystallization during high-temperature heat treatment and suppressing crystal grain growth. Addition of 0.1% by mass or more greatly reduces the conductivity and saturates the effect.

Ｃｏも高温熱処理時の再結晶を遅らせ、結晶粒成長を抑制する作用がある。また、Ｆｅに比べ導電率の低下が少ない。   Co also has an action of delaying recrystallization during high-temperature heat treatment and suppressing crystal grain growth. Moreover, there is little decrease in electrical conductivity compared to Fe.

ＭｎもＳと化合物を生成して粒界のＳを固定し、熱間加工性を向上させる効果があるが、導電率の低下をもたらす。   Mn also produces a compound with S to fix S at the grain boundary and improve the hot workability, but lowers the conductivity.

Ｚｒ、Ｔｉ、Ｃｒは強度と耐熱性を向上させる効果があるが、酸化物の巻き込み等の鋳造性の低下をもたらす。   Zr, Ti, and Cr have the effect of improving strength and heat resistance, but lower castability such as oxide entrainment.

Ａｇは耐熱性を向上させる効果がある。   Ag has the effect of improving heat resistance.

（２）製造方法
通常坩堝式溶解炉やチャネル式溶解炉等の電気炉で所定の成分を溶解後、連続鋳造により厚さ１５０ｍｍ以上２５０ｍｍ以下、幅４００ｍｍ以上１０００ｍｍ以下程度の矩形断面鋳塊（ケーク）を鋳造する。ケークを８００℃以上９５０℃以下の温度において３０分以上保持後、熱間圧延機により厚さ１０ｍｍ以上１５ｍｍ以下まで圧延する。熱間圧延の加熱温度が８００℃より低いと、熱間圧延時に粒界に割れを生じる。また、鋳造の冷却過程で析出した粗大な析出物が充分に固溶しない。一方、９５０℃より高いと再結晶した結晶が粗大化し易く、また酸化膜が厚くなる。従って、熱間圧延の加熱温度は８００℃以上９５０℃以下とする。また、保持時間は３０分より短くても析出物が充分に固溶しないため、保持時間は３０分以上とする。更に、熱間圧延終了温度は６５０℃以上とし、毎分３００℃以上の冷却速度で水冷することが望ましい。熱間圧延終了温度を高くし、その後の冷却速度を速くすることで、時効処理の際に高い強度を得ることができる。また、鋳塊を厚さ２０ｍｍ程度の薄板に鋳造しても良く、この場合熱間圧延は不要である。 (2) Manufacturing method After a predetermined component is melted in an electric furnace such as a crucible melting furnace or a channel melting furnace, a rectangular cross-section ingot having a thickness of 150 mm to 250 mm and a width of 400 mm to 1000 mm is obtained by continuous casting (cake) ). The cake is held at a temperature of 800 ° C. or more and 950 ° C. or less for 30 minutes or more, and then rolled to a thickness of 10 mm or more and 15 mm or less by a hot rolling mill. When the heating temperature of hot rolling is lower than 800 ° C., cracks occur at the grain boundaries during hot rolling. Further, coarse precipitates precipitated during the cooling process of casting are not sufficiently dissolved. On the other hand, when the temperature is higher than 950 ° C., the recrystallized crystal is easily coarsened and the oxide film becomes thick. Therefore, the heating temperature of hot rolling is set to 800 ° C. or more and 950 ° C. or less. Further, even if the holding time is shorter than 30 minutes, the precipitate is not sufficiently dissolved, so that the holding time is 30 minutes or more. Furthermore, it is desirable that the hot rolling end temperature is 650 ° C. or higher, and water cooling is performed at a cooling rate of 300 ° C. or more per minute. By increasing the hot rolling end temperature and increasing the subsequent cooling rate, high strength can be obtained during the aging treatment. Further, the ingot may be cast into a thin plate having a thickness of about 20 mm. In this case, hot rolling is not necessary.

熱間圧延後面削により酸化膜を除去する。その後、少なくとも１５％以上の加工率で冷間圧延した後、時効処理を施す。時効処理前の冷間圧延加工率が１５％未満では析出サイトが不足し、析出速度が遅くなるとともに強度が上がりにくくなる。望ましくは５０％以上８０％以下である。また、より高い強度が必要な場合には、所定の厚さに冷間圧延後、７５０℃以上の温度において１分以上５分未満加熱し、その後毎分２００℃以上の冷却速度で水冷して溶体化処理を施す。その後、少なくとも１５％以上の加工率で冷間圧延した後、時効処理を施す。   The oxide film is removed by chamfering after hot rolling. Then, after cold rolling at a processing rate of at least 15% or more, an aging treatment is performed. If the cold rolling ratio before the aging treatment is less than 15%, the precipitation sites are insufficient, the precipitation rate becomes slow and the strength is hardly increased. Desirably, it is 50% or more and 80% or less. When higher strength is required, after cold rolling to a predetermined thickness, heat at a temperature of 750 ° C or higher for 1 minute or more and less than 5 minutes, and then cool with water at a cooling rate of 200 ° C or more per minute. Apply solution treatment. Then, after cold rolling at a processing rate of at least 15% or more, an aging treatment is performed.

時効処理は３５０℃以上５００℃以下の温度において３０分以上２４時間以下保持する。時効処理温度が３５０℃未満では析出速度が遅く、２４時間以上加熱しても充分析出しない。時効処理温度が５００℃を超えると微細な析出物が得られず充分な時効硬化が得られない。この場合に最終的に高い強度を得ようとすると、時効処理後の圧延での加工率を高くして加工強化により強度を向上させることができるが、加熱した際の圧延方向への伸び率が大きくなる。望ましくは４２０℃以上４８０℃以下の温度において１時間以上４時間以下とする。   The aging treatment is maintained for 30 minutes to 24 hours at a temperature of 350 ° C. to 500 ° C. When the aging temperature is less than 350 ° C., the deposition rate is slow, and even when heated for 24 hours or more, it does not precipitate sufficiently. If the aging treatment temperature exceeds 500 ° C., fine precipitates cannot be obtained and sufficient age hardening cannot be obtained. In this case, when trying to finally obtain a high strength, it is possible to increase the processing rate in rolling after aging treatment and improve the strength by processing strengthening, but the elongation rate in the rolling direction when heated is increased. growing. Desirably, it is 1 hour or more and 4 hours or less at the temperature of 420 degreeC or more and 480 degrees C or less.

時効処理後に最終冷間圧延を行うが、時効処理後の硬さに対する最終冷間圧延後の硬さの硬化率は１０％以下とする。１０％を超えると冷間圧延により付加された加工歪み量が増大し、加熱した際の圧延方向への伸び率が大きくなる。また、時効処理は冷間圧延を挟んで２回以上施しても良いが、この場合は最終時効処理後の硬さに対する最終冷間圧延後の硬さの硬化率を１０％以下とする。更に、最終冷間圧延の間に複数回の焼鈍を加えても良いが、この場合各焼鈍後の硬さと時効後の硬さのうち最も低い硬さに対する最終冷間圧延後の硬さの硬化率が１０％以下であることを条件とする。   Although the final cold rolling is performed after the aging treatment, the hardening rate of the hardness after the final cold rolling with respect to the hardness after the aging treatment is set to 10% or less. If it exceeds 10%, the amount of work strain added by cold rolling increases, and the elongation in the rolling direction when heated is increased. The aging treatment may be performed twice or more with the cold rolling interposed therebetween. In this case, the hardening rate of the hardness after the final cold rolling relative to the hardness after the final aging treatment is set to 10% or less. Further, multiple annealing may be applied during the final cold rolling, but in this case, the hardness after the final cold rolling for the lowest hardness among the hardness after each annealing and the hardness after aging. The condition is that the rate is 10% or less.

最終冷間圧延後には歪み除去焼鈍を施す。歪み除去焼鈍は３００℃以上５５０℃以下の温度において３０秒以上３分以下保持する。温度が３００℃未満や保持時間が１分未満では加工歪みが充分除去できず、伸びが不足するとともに加熱した際の圧延方向への伸び率が大きくなる。温度が５５０℃を超えると導電率や強度の低下が大きくなる。   After final cold rolling, strain relief annealing is performed. The strain removal annealing is held at a temperature of 300 ° C. or more and 550 ° C. or less for 30 seconds or more and 3 minutes or less. If the temperature is less than 300 ° C. or the holding time is less than 1 minute, the processing strain cannot be sufficiently removed, the elongation is insufficient, and the elongation in the rolling direction when heated is increased. When temperature exceeds 550 degreeC, the fall of electrical conductivity and intensity | strength will become large.

まず、表１に示すように成分、熱間圧延条件、溶体化条件、時効前加工率、時効条件を変えて数種の銅合金を作製し各成分の銅合金を高周波溶解炉で溶解後、ＳＵＳ製鋳型に鋳込んで厚さ２０ｍｍの鋳塊を鋳造した。次に各熱間圧延条件で熱間圧延を実施して厚さ８ｍｍに仕上げ、酸化スケールを除去後、冷間圧延を実施した。本発明のＮｏ．４のみ厚さ２．５ｍｍにて溶体化処理を行った後、冷間圧延にて厚さ１ｍｍとした。その後、各時効前加工率にて冷間圧延を実施し、４７０℃の温度において２時間の時効処理を実施した後、加工率５０％で最終圧延し、４５０℃の温度において1分間の歪み除去焼鈍を実施した。   First, as shown in Table 1, after changing the components, hot rolling conditions, solution conditions, pre-aging processing rate, aging conditions and preparing several types of copper alloys, melting each component copper alloy in a high-frequency melting furnace, An ingot having a thickness of 20 mm was cast by casting in a SUS mold. Next, hot rolling was performed under each hot rolling condition to finish to a thickness of 8 mm, and after removing the oxide scale, cold rolling was performed. No. of the present invention. Only 4 was subjected to a solution treatment at a thickness of 2.5 mm, and then cold-rolled to a thickness of 1 mm. Then, cold rolling is performed at each pre-aging rate, aging treatment is performed for 2 hours at a temperature of 470 ° C., then final rolling is performed at a processing rate of 50%, and strain is removed at a temperature of 450 ° C. for 1 minute. Annealing was performed.

表２にこれらのサンプルの熱間加工性、歪み除去焼鈍後の導電率、引張強さ、めっき性について評価した結果を示す。Ｎｏ．１〜４はいずれも熱間加工性やめっき性は良好で、特性的にも問題は見られなかった。ＮｉとＳｉの含有量が多いほど高い強度が得られる。一方、Ｎｏ．５はＮｉ、Ｓｉの含有量が少なく、充分な強度が得られず、Ｎｏ．６はＮｉ、Ｓｉの含有量が多く、熱間圧延時に結晶粒界で割れ、めっき前の酸洗で残渣が大量に発生するといった問題が生じた。Ｎｏ．７〜９は化学組成はＮｏ．２と同一であるが、Ｎｏ．７は熱間圧延の加熱温度が低く、結晶粒界に微小な割れを生じた。加熱温度８６０℃では結晶粒の内外に析出物はほとんど見られなかったが、７７０℃では析出物が多く見られた。また、熱間圧延後の断面には未再結晶粒が多く見られた。Ｎｏ．８は熱間圧延の加熱温度が高く、再結晶粒が粗大化した。Ｎｏ．９は時効処理前の加工率が低く、析出が充分に進まず低い導電率と低い強度となった。   Table 2 shows the results of evaluating the hot workability, electrical conductivity after strain-removal annealing, tensile strength, and plating properties of these samples. No. In all of Nos. 1 to 4, the hot workability and plating properties were good, and no problem was found in the characteristics. The higher the Ni and Si contents, the higher the strength. On the other hand, no. No. 5 has a low content of Ni and Si, and sufficient strength cannot be obtained. No. 6 had a large content of Ni and Si, and cracks occurred at the grain boundaries during hot rolling, and a large amount of residue was generated by pickling before plating. No. 7 to 9 have chemical compositions No. No. 2 but no. In No. 7, the heating temperature of the hot rolling was low, and minute cracks were generated at the grain boundaries. At the heating temperature of 860 ° C., almost no precipitates were observed inside and outside the crystal grains, but at 770 ° C., many precipitates were observed. Moreover, many non-recrystallized grains were seen in the cross section after hot rolling. No. In No. 8, the heating temperature of hot rolling was high, and the recrystallized grains became coarse. No. No. 9 had a low processing rate before aging treatment, and the precipitation did not proceed sufficiently, resulting in low conductivity and low strength.

次に、表２の結果に基づき、Ｎｏ．２（実施例１）と同一の製造条件で厚さ１ｍｍまで冷間圧延後、表３に示すように時効条件、最終圧延加工率、歪み除去焼鈍条件を変えて数種のサンプルを作製し、時効後及び最終圧延後のビッカース硬さ、歪み除去焼鈍後の導電率、引張強さを評価した。更に５００℃の温度において５分間の加熱を実施し、加熱前後での圧延方向の寸法変化を測定して伸縮率（伸び率）を算出した。この際、サンプルは長さ２５０ｍｍ、幅１０ｍｍとし、Ａｒ雰囲気において無張力状態で加熱した。寸法測定の標点間距離は２００ｍｍとした。本発明である実施例１および実施例２〜実施例４はいずれも最終圧延での硬化率（（最終圧延後の硬さ／時効処理後の硬さ−1）×100）は１０％以下であり、加熱伸縮率は５０ｐｐｍ以下である。歪み除去焼鈍後の導電率及び引張強さも良好である。一方、比較例１〜比較例３は時効後の硬さが低く、硬化率はいずれも２０％を超えている。この結果、加熱伸縮率は５０ｐｐｍを大きく超えている。また、比較例４は比較例３と同一の時効条件であるが、最終圧延加工率を高くして加工硬化により強度を上げようとしたものだが、効果率が５０％近いために加熱伸縮率は２５０ｐｐｍ以上の高い値となった。また、過時効条件であるために耐熱性が低く、歪み除去焼鈍での強度低下が大きい。比較例５は最終圧延まで実施例１と同一の製造工程であり、歪み除去焼鈍条件のみ６００℃の温度において1分間の加熱としたが、強度低下が大きい。   Next, based on the results of Table 2, After cold-rolling to a thickness of 1 mm under the same production conditions as 2 (Example 1), as shown in Table 3, changing the aging conditions, the final rolling process rate, the strain-removal annealing conditions, and producing several samples, Vickers hardness after aging and final rolling, electrical conductivity after strain removal annealing, and tensile strength were evaluated. Furthermore, heating was performed at a temperature of 500 ° C. for 5 minutes, and the dimensional change in the rolling direction before and after the heating was measured to calculate the expansion / contraction rate (elongation rate). At this time, the sample had a length of 250 mm and a width of 10 mm, and was heated in a no-tension state in an Ar atmosphere. The distance between gauge points for dimension measurement was 200 mm. In Example 1 and Examples 2 to 4 which are the present invention, the curing rate in final rolling ((hardness after final rolling / hardness after aging treatment-1) × 100) is 10% or less. Yes, the heat expansion / contraction rate is 50 ppm or less. The electrical conductivity and tensile strength after strain removal annealing are also good. On the other hand, Comparative Examples 1 to 3 have a low hardness after aging, and the curing rate exceeds 20%. As a result, the heat expansion / contraction rate greatly exceeds 50 ppm. Comparative Example 4 has the same aging conditions as Comparative Example 3, but the final rolling process rate was increased to increase the strength by work hardening. A high value of 250 ppm or more was obtained. Moreover, since it is an overaging condition, heat resistance is low, and the strength reduction by distortion removal annealing is large. Comparative Example 5 is the same manufacturing process as Example 1 up to the final rolling, and heating was performed for 1 minute at a temperature of 600 ° C. only for the strain-removal annealing conditions, but the strength was greatly reduced.

Claims (3)

Ｎｉを１．０質量％以上４．０質量％以下、Ｓｉを０．２質量％以上１．２質量％以下含有し、残部がＣｕと不可避不純物からなる銅基合金を鋳造し、熱間圧延により圧延後、１５％以上の加工率で冷間圧延を施し、３００℃以上５００℃以下の温度において３０分以上２４時間以下の時効処理を施し、その後最終冷間圧延を行い、更に３００℃以上５５０℃以下の温度で３０秒以上３分以下の歪み除去焼鈍を行う銅合金の製造方法において、時効処理後の硬さに対する最終冷間圧延後の硬さの硬化率を１０％以下とすることを特徴とする電気・電子部品用高強度銅合金の製造方法。   Cast a copper-based alloy containing Ni from 1.0% by mass to 4.0% by mass, Si from 0.2% by mass to 1.2% by mass, the balance being Cu and inevitable impurities, and hot rolling After rolling, cold rolling is performed at a processing rate of 15% or more, aging treatment is performed for 30 minutes to 24 hours at a temperature of 300 ° C. to 500 ° C., and then final cold rolling is performed, and further 300 ° C. or more is performed. In a copper alloy manufacturing method that performs strain relief annealing at a temperature of 550 ° C. or lower for 30 seconds or longer and 3 minutes or shorter, the hardening rate of the hardness after the final cold rolling relative to the hardness after the aging treatment should be 10% or less. A method for producing a high-strength copper alloy for electric and electronic parts. 請求項１において、前記銅基合金は、Ｎｉを１．０質量％以上４．０質量％以下、Ｓｉを０．２質量％以上１．２質量％以下含有し、更にＰ、Ｚｎ、Ｓｎ、Ｍｇ、Ｆｅ、Ｃｏ、Ｍｎ、Ｚｒ、Ｔｉ、Ｃｒ、Ａｇのいずれか１種類以上を総量で２．０質量％未満含有し、残部がＣｕと不可避不純物からなることを特徴とする電気・電子部品用高強度銅合金の製造方法。   In Claim 1, the said copper base alloy contains 1.0 mass% or more and 4.0 mass% or less of Ni, 0.2 mass% or more and 1.2 mass% or less of Si, Furthermore, P, Zn, Sn, An electrical / electronic component characterized by containing at least one of Mg, Fe, Co, Mn, Zr, Ti, Cr, and Ag in a total amount of less than 2.0 mass%, with the balance being Cu and inevitable impurities For producing high-strength copper alloys for industrial use. 前記熱間圧延は、８００℃以上９５０℃以下の温度において３０分以上保持後圧延する請求項１または２のいずれかに記載の電気・電子部品用高強度銅合金の製造方法。   The said hot rolling is a manufacturing method of the high strength copper alloy for electrical / electronic components in any one of Claim 1 or 2 which is rolled after hold | maintaining for 30 minutes or more at the temperature of 800 degreeC or more and 950 degrees C or less.