JP2008038231A - High-strength sheet material of copper alloy superior in bendability, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material of a Cu-Ni-Si copper alloy, which has both strength and bendability after notching balanced at a high level. <P>SOLUTION: The sheet material of the copper alloy has a composition comprising, by mass%, 0.7 to 2.5% Ni, 0.2 to 0.7% Si, 0.1 to 1.2% Sn, further 2.0% or less Zn as needed, or further 0.3% or less Mg, and the balance substantially Cu; and has a crystalline orientation which satisfies the following expression (1): 0.1≤Iä420}/Iä220}≤0.5, wherein Iä420} and Iä220} indicate X-ray diffraction intensities of a crystal face ä420} and a crystal face ä220} respectively in the sheet plane of the sheet material. The sheet material can include further one or more elements of Co, Cr, B, P, Fe, Zr, Ti and Mn in a total amount of 3% or less, in addition to the above composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、コネクター、リードフレーム、リレー、スイッチなどの電気・電子部品に適した銅合金材料であって、特に高強度および高導電性を維持しながら、曲げ加工性に優れた銅合金板材に関する。   The present invention relates to a copper alloy material suitable for electrical and electronic parts such as connectors, lead frames, relays, switches, etc., and particularly to a copper alloy plate material excellent in bending workability while maintaining high strength and high conductivity. .

電気・電子部品を構成するコネクター、リードフレーム、リレー、スイッチなどの通電部品に使用される材料には、通電によるジュール熱の発生を抑制するために良好な「導電性」が要求されるとともに、電気・電子機器の組立時や作動時に付与される応力に耐え得る高い「強度」が要求される。また、電気・電子部品は一般に曲げ加工により成形されることから優れた「曲げ加工性」も要求される。   The materials used for current-carrying parts such as connectors, lead frames, relays, and switches that make up electrical and electronic parts are required to have good "conductivity" to suppress the generation of Joule heat due to current flow. High “strength” is required to withstand the stress applied during assembly and operation of electrical and electronic equipment. In addition, since electric / electronic parts are generally formed by bending, excellent “bending workability” is also required.

「曲げ加工性」に対する要求は曲げ部に割れが生じないだけではなく、曲げ加工品の形状・寸法精度を確保できることも重要である。曲げ加工において多かれ少なかれ現れる面倒な問題としてスプリングバックが挙げられる。スプリングバックは、材料を加工後に金型から取り出したときに弾性的な変形の回復が起こり、金型の中で加工されていたときの形状とは一致しなくなる現象である。   The requirement for “bending workability” is not only that cracks do not occur in the bent part, but also that it is important to ensure the shape and dimensional accuracy of the bent product. A troublesome problem that appears more or less in bending is springback. Springback is a phenomenon in which elastic deformation recovers when the material is removed from the mold after processing, and does not match the shape when processed in the mold.

近年、電気・電子部品は高集積化、小型化および軽量化が進む傾向にあり、それに伴って素材である銅および銅合金には薄肉化の要求が高まっている。そのため、素材に要求される強度レベルは一層厳しいものとなっている。このような状況下では部品の形状・寸法精度の向上が極めて重要であり、スプリングバックの問題が顕在化しやすい。   In recent years, electrical and electronic parts have been increasingly integrated, miniaturized and lightened, and accordingly, copper and copper alloys as materials have been required to be thin. For this reason, the strength level required for the material is more severe. Under such circumstances, it is extremely important to improve the shape and dimensional accuracy of the parts, and the problem of springback is likely to become obvious.

スプリングバックを軽減するためには、一般に素材の品種に応じて金型の設計・調整を行うことが有効である。しかし、素材の品種ごとに適正な金型を準備することはコスト的に不利である。   In order to reduce the springback, it is generally effective to design and adjust the mold according to the type of material. However, it is disadvantageous in cost to prepare an appropriate mold for each kind of material.

一方、近年、曲げ加工品の形状・寸法精度を向上させるために、素材の曲げ加工を施す部位にノッチを付ける加工（ノッチング）を施し、その後、そのノッチに沿って曲げ加工を行う加工法（以下「ノッチング後曲げ加工法」という）が採用されている。この加工法は、曲げ部の位置精度の向上とともに、スプリングバックの軽減に極めて有効である。   On the other hand, in recent years, in order to improve the shape and dimensional accuracy of bent products, a method of notching (notching) the part of the material to be bent, and then bending along the notch ( Hereinafter, the “bending method after notching”) is employed. This processing method is extremely effective for improving the positional accuracy of the bent portion and reducing the springback.

電気・電子部品に適した銅合金材料として、近年、Ｃｕ−Ｎｉ−Ｓｉ系合金（いわゆるコルソン合金）が注目されている。一般に銅合金において「強度」と「導電性」、あるいは特に「強度」と「曲げ加工性」の間にはトレードオフの関係があり、これらを同時に満足させることは難しいとされる。そのような中で、Ｃｕ−Ｎｉ−Ｓｉ系合金は「強度」と「導電性」の特性バランスに比較的優れている。例えば、溶体化処理、冷間圧延、時効処理、仕上げ冷間圧延、低温焼鈍を基本とする工程により、比較的高い導電率（３０〜５０％ＩＡＣＳ）を維持しながら、強度を顕著に向上させることができる。ただし、Ｃｕ−Ｎｉ−Ｓｉ系合金の曲げ加工性は必ずしも良好であるとは限らず、この点を改善するために析出物や結晶粒形態を制御する手法が種々提案されている。また、結晶方位（集合組織）を制御することも提案されている（特許文献１〜５）。   In recent years, Cu—Ni—Si based alloys (so-called Corson alloys) have attracted attention as copper alloy materials suitable for electric and electronic parts. In general, there is a trade-off relationship between “strength” and “conductivity” or particularly “strength” and “bending workability” in a copper alloy, and it is difficult to satisfy these simultaneously. Under such circumstances, the Cu—Ni—Si based alloy is relatively excellent in the characteristic balance between “strength” and “conductivity”. For example, the strength is remarkably improved while maintaining a relatively high conductivity (30 to 50% IACS) by a process based on solution treatment, cold rolling, aging treatment, finish cold rolling, and low temperature annealing. be able to. However, the bending workability of Cu—Ni—Si based alloys is not always good, and various methods for controlling precipitates and crystal grain forms have been proposed in order to improve this point. It has also been proposed to control the crystal orientation (texture) (Patent Documents 1 to 5).

特開２０００−８０４２８号公報JP 2000-80428 A 特開２００６−９１０８号公報JP 2006-9108 A 特開２００６−９１３７号公報JP 2006-9137 A 特開２００６−１６６２９号公報JP 2006-16629 A 特開２００６−１５２３９２号公報JP 2006-152392 A

上記のように、銅合金板材において「ノッチング後曲げ加工法」を採用することは、曲げ加工時の位置精度の向上およびスプリングバック軽減による寸法精度の向上に効果的であり、これはＣｕ−Ｎｉ−Ｓｉ系銅合金においても有効である。しかしながら、Ｃｕ−Ｎｉ−Ｓｉ系合金は、特に更なる高強度化を図ろうとした場合、「ノッチング後曲げ加工法」によって曲げ部に割れを生じやすいという欠点を有する。特許文献１〜５のように集合組織を制御して曲げ加工性の改善を図ったＣｕ−Ｎｉ−Ｓｉ系合金であっても、「ノッチング後曲げ加工法」による割れ発生を防止することまでは考慮されておらず、ノッチング後の曲げ加工性は十分に改善されていない。例えば特許文献５には、９５％以上の圧延率で冷間圧延した後、溶体化処理を施し、その後、冷間圧延と時効処理を施す工程が開示されており、それによって７００ＭＰａ以上の引張強さを有するものにおいて曲げ加工性の改善が図られている。しかし、単にこのような工程を採用しても、通常の曲げ加工性の改善に加え、さらにノッチング後の曲げ加工性まで改善することは困難である（後述の表２、比較例２３参照）。   As described above, adopting the “bending method after notching” in the copper alloy sheet material is effective in improving the positional accuracy during bending and improving the dimensional accuracy by reducing the spring back, which is effective for Cu—Ni. -It is also effective for Si-based copper alloys. However, the Cu—Ni—Si alloy has a drawback that cracking tends to occur in the bent portion by the “bending method after notching” particularly when trying to further increase the strength. Even in the case of Cu-Ni-Si based alloys that have improved the bending workability by controlling the texture as in Patent Documents 1-5, until the occurrence of cracking due to the "bending process after notching" is prevented. This is not considered, and the bending workability after notching is not sufficiently improved. For example, Patent Document 5 discloses a process in which cold rolling is performed at a rolling rate of 95% or more, solution treatment is performed, and then cold rolling and aging treatment are performed, whereby a tensile strength of 700 MPa or more is disclosed. Bending workability is improved in those having a thickness. However, even if such a process is simply adopted, it is difficult to improve the bending workability after notching in addition to the normal bending workability improvement (see Table 2 and Comparative Example 23 described later).

このように、強度と導電性のバランスに比較的優れるＣｕ−Ｎｉ−Ｓｉ系銅合金において、更なる高強度化を図りながら部品の形状・寸法精度向上のための「ノッチング後曲げ加工法」を適用した際の割れ発生を防止する技術は未だ確立されていない。
本発明は、この合金系において、特に強度とノッチング後の曲げ加工性を高レベルに両立した銅合金板材を提供することを目的とする。 In this way, in the Cu-Ni-Si based copper alloy, which has a relatively good balance between strength and conductivity, the "bending method after notching" is used to improve the shape and dimensional accuracy of parts while further increasing the strength. A technique for preventing the occurrence of cracks when applied has not been established yet.
An object of the present invention is to provide a copper alloy sheet material in which the strength and the bending workability after notching are compatible at a high level in this alloy system.

発明者らは詳細な検討の結果、Ｃｕ−Ｎｉ−Ｓｉ系合金は一般に冷間圧延によって｛２２０｝結晶面を主方位成分とする圧延集合組織が発達するが、予め｛４２０｝結晶面を主方位成分の１つとする再結晶集合組織を得ておくと、冷間圧延によって｛２２０｝を主方位成分とする集合組織を発達させたとき、｛４２０｝を主方位成分とする結晶粒が特定の割合で残存するような圧延集合組織が得られ、これによって高強度化とノッチング後の曲げ加工性顕著が同時に達成できることを見出した。   As a result of detailed examinations, the inventors have generally developed a rolling texture having a {220} crystal plane as a main orientation component by cold rolling, but the {420} crystal plane is preliminarily formed in the Cu-Ni-Si alloy. If a recrystallized texture with one orientation component is obtained, a crystal grain with {420} as the main orientation component is identified when a texture with {220} as the main orientation component is developed by cold rolling. It has been found that a rolled texture that remains at a ratio of 5% can be obtained, whereby high strength and remarkable bending workability after notching can be achieved simultaneously.

すなわち本発明では、質量％で、Ｎｉ：０.７〜２.５％、Ｓｉ：０.２〜０.７％、Ｓｎ：０.１〜１.２％を含有し、必要に応じてさらにＺｎ：２.０％以下、あるいはさらにＭｇ：０.３％以下を含み、残部実質的にＣｕの組成を有し、下記（１）式を満たす結晶配向を有する銅合金板材が提供される。上記組成において、さらにＣｏ、Ｃｒ、Ｂ、Ｐ、Ｆｅ、Ｚｒ、Ｔｉ、Ｍｎの１種以上を合計３％以下の範囲で含有させることができる。
０.１≦Ｉ｛４２０｝／Ｉ｛２２０｝≦０.５ ……（１）
ここで、Ｉ｛４２０｝およびＩ｛２２０｝はそれぞれ当該板材の板面における｛４２０｝結晶面および｛２２０｝結晶面のＸ線回折強度である。「板面」は板の厚さ方向に垂直な表面（圧延面）である。 That is, in the present invention, by mass, Ni: 0.7 to 2.5%, Si: 0.2 to 0.7%, Sn: 0.1 to 1.2% are contained, and if necessary, further There is provided a copper alloy sheet material containing Zn: 2.0% or less, or further Mg: 0.3% or less, the balance being substantially Cu, and having a crystal orientation satisfying the following formula (1). In the above composition, one or more of Co, Cr, B, P, Fe, Zr, Ti, and Mn can be further contained within a total range of 3% or less.
0.1 ≦ I {420} / I {220} ≦ 0.5 (1)
Here, I {420} and I {220} are the X-ray diffraction intensities of the {420} crystal plane and the {220} crystal plane on the plate surface of the plate material, respectively. The “plate surface” is a surface (rolled surface) perpendicular to the thickness direction of the plate.

「残部実質的にＣｕ」とは、本発明の効果を阻害しない範囲で上記以外の元素の混入が許容されることを意味し、「残部がＣｕおよび不可避的不純物」である場合が含まれる。   “Remainder substantially Cu” means that mixing of elements other than the above is allowed within a range not impairing the effects of the present invention, and includes the case where “remainder is Cu and inevitable impurities”.

この銅合金板材は、例えば、板面において圧延方向に対し平行方向をＬＤ、直角方向をＴＤと呼ぶとき、当該板材から長手方向がＬＤになるように採取された短冊形試料の片面に、図１に示す断面形状のノッチ形成治具を用いて、深さが板厚の１／８〜１／２、方向がＴＤのノッチを試料幅いっぱいに形成したノッチ付き曲げ試験片について、下記のノッチ曲げ試験を実施したとき、当該試験片表面に割れが認められない曲げ加工性を有する。   For example, when the copper alloy sheet is called LD as the direction parallel to the rolling direction and TD as the direction perpendicular to the rolling direction on the sheet surface, A notched bending test piece in which a notch having a depth of 1/8 to 1/2 and a direction of TD is formed to fill the sample width using the notch forming jig having the cross-sectional shape shown in FIG. When a bending test is carried out, it has bending workability in which no cracks are observed on the surface of the test piece.

〔ノッチ曲げ試験〕
ＪＩＳ Ｈ３１１０に規定される９０°Ｗ曲げ試験において下型の中央突起部先端のＲを０ｍｍとした治具を用意し、前記ノッチ付き曲げ試験片を、ノッチ形成面が下向きになり、前記下型の中央突起部先端がノッチ部分に合致するようにセットして９０°Ｗ曲げ試験を行う。 [Notch bending test]
In the 90 ° W bending test specified in JIS H3110, a jig was prepared in which the R at the tip of the central projection of the lower die was 0 mm. The notched bending test piece was placed with the notch forming surface facing downward. A 90 ° W bend test is performed by setting the tip of the central protrusion of the core to match the notch.

また、異方性の小さい銅合金板材として、長手方向がＴＤになるように採取された短冊形試料を用いて上記のノッチ曲げ試験を実施したときにも、当該試験片表面に割れが認められない曲げ加工性を有するものが特に好ましい対象となる。
これらは、時効処理を経た組織を有し、引張強さが６５０ＭＰａ以上あるいはさらに７００ＭＰａ以上を呈するものである。 In addition, when the above-mentioned notch bending test was performed using a strip-shaped sample collected so that the longitudinal direction was TD as a copper alloy sheet material with small anisotropy, cracks were observed on the surface of the test piece. Those having no bending workability are particularly preferred.
These have a structure that has undergone an aging treatment and exhibit a tensile strength of 650 MPa or more, or even 700 MPa or more.

図２にはノッチング方法を模式的に示してある。
図３にはノッチ付き曲げ試験片（曲げ試験前）についてノッチ形成部分の長手方向に垂直な断面形状を模式的に示してある。板厚をｔ（ｍｍ）、ノッチ深さをδ（ｍｍ）とするとき、δ／ｔが１／８（すなわち０.１２５）以上、１／２（すなわち０.５）以下になるようにノッチが形成されている。この範囲のノッチが形成されたノッチ付き曲げ試験片を用いて９０°曲げ試験に供したとき、試験片に割れが生じなければ、部品加工に際し「ノッチング後曲げ加工法」を適用した際に優れた割れ防止効果が得られる。 FIG. 2 schematically shows the notching method.
FIG. 3 schematically shows a cross-sectional shape perpendicular to the longitudinal direction of the notch forming portion of the notched bending specimen (before the bending test). When the plate thickness is t (mm) and the notch depth is δ (mm), the notch is such that δ / t is 1/8 (ie, 0.125) or more and 1/2 (ie, 0.5) or less. Is formed. When subjected to a 90 ° bending test using a notched bending test piece in which this range of notches is formed, if the test piece does not crack, it is excellent when the “bending method after notching” is applied to the part processing. The crack prevention effect is obtained.

この銅合金板材の製造法として、上記のように組成調整された銅合金材料に対し、圧延率８５％以上の冷間圧延、加熱温度７００〜８００℃未満の溶体化処理、圧延率０〜５０％の中間冷間圧延、材温４００〜５００℃の時効処理、下記（２）式を満たす圧延率での仕上げ冷間圧延を順次施す工程を有する銅合金板材の製造法が提供される。仕上げ冷間圧延後に、さらに１５０〜５５０℃の加熱処理を施す工程を採用することが好ましい。
１０≦ε₂≦（６５−ε₁）／（１００−ε₁）×１００ ……（２）
ここで、ε₁は中間冷間圧延率（％）、ε₂は仕上げ冷間圧延率（％）である。
圧延率ε（％）は、圧延前の板厚をｔ₀、圧延後の板厚をｔ₁とすると、下記（３）式で表される。
ε＝（ｔ₀−ｔ₁）／ｔ₀×１００ ……（３）
なお、上記の「圧延率０％」は、当該中間冷間圧延を行わない場合を意味する。 As a manufacturing method of this copper alloy sheet, cold rolling with a rolling rate of 85% or more, solution treatment with a heating temperature of less than 700 to 800 ° C., rolling rate of 0 to 50 with respect to the copper alloy material whose composition is adjusted as described above. % Intermediate cold rolling, an aging treatment at a material temperature of 400 to 500 ° C., and a finish cold rolling at a rolling rate satisfying the following formula (2) are sequentially provided. It is preferable to employ a step of performing a heat treatment at 150 to 550 ° C. after the finish cold rolling.
10 ≦ ε ₂ ≦ (65−ε ₁ ) / (100−ε ₁ ) × 100 (2)
Here, ε ₁ is the intermediate cold rolling rate (%), and ε ₂ is the finish cold rolling rate (%).
The rolling rate ε (%) is expressed by the following equation (3), where t _{0 is} the thickness before rolling and t ₁ is the thickness after rolling.
ε = (t ₀ −t ₁ ) / t ₀ × 100 (3)
In addition, said "rolling rate 0%" means the case where the said intermediate cold rolling is not performed.

本発明によれば、コネクター、リードフレーム、リレー、スイッチなどの電気・電子部品に必要な基本特性を具備するＣｕ−Ｎｉ−Ｓｉ系銅合金の板材において、引張強さ６５０ＭＰａ以上あるいはさらに７００ＭＰａ以上の高強度と、「ノッチング後曲げ加工法」を適用した際の割れ発生が顕著に防止できる優れた曲げ加工性を有するものが提供された。このような高強度レベルにおいて引張強さと曲げ加工性が安定して顕著に向上することは、従来のＣｕ−Ｎｉ−Ｓｉ系銅合金製造技術では困難であった。本発明は、今後ますます進展が予想される電気・電子部品の小型化、薄肉化のニーズに対応し得るものである。   According to the present invention, in a Cu-Ni-Si based copper alloy plate having basic characteristics required for electrical / electronic components such as connectors, lead frames, relays, switches, etc., the tensile strength is 650 MPa or more, or even 700 MPa or more. A material having high strength and excellent bending workability capable of remarkably preventing the occurrence of cracking when the “notched bending method” is applied has been provided. It has been difficult for the conventional Cu—Ni—Si based copper alloy manufacturing technology to stably and significantly improve the tensile strength and the bending workability at such a high strength level. The present invention can meet the needs for downsizing and thinning of electric and electronic parts, which are expected to make further progress in the future.

Ｃｕ−Ｎｉ−Ｓｉ系銅合金の場合、板表面（圧延面）からのＸ線回折パターンは一般に｛１１１｝、｛２００｝、｛２２０｝、｛３１１｝の４つの結晶面の回折ピークで構成される。冷間圧延率の増大に伴い｛２２０｝面のＸ線回折強度が相対的に増大し、｛２００｝面と｛３１１｝面の回折強度が減少する。｛１１１｝面の回折強度は通常、若干増加する傾向にある。他の結晶面からのＸ線回折強度はこれらの結晶面からのものに比べ非常に小さい。特に、通常の組成を有するＣｕ−Ｎｉ−Ｓｉ系銅合金を通常の製造工程に供して板材を得た場合、その板材では｛４２０｝面のＸ線回折強度は無視される程度に弱くなる。   In the case of a Cu—Ni—Si based copper alloy, the X-ray diffraction pattern from the plate surface (rolled surface) is generally composed of diffraction peaks of four crystal planes {111}, {200}, {220}, and {311}. Is done. As the cold rolling rate increases, the X-ray diffraction intensity of the {220} plane increases relatively, and the diffraction intensity of the {200} plane and {311} plane decreases. The diffraction intensity of the {111} plane usually tends to increase slightly. X-ray diffraction intensities from other crystal planes are much smaller than those from these crystal planes. In particular, when a Cu-Ni-Si-based copper alloy having a normal composition is subjected to a normal manufacturing process to obtain a plate material, the {420} plane X-ray diffraction intensity of the plate material becomes weak enough to be ignored.

本発明では、前記（１）式を満たすように｛４２０｝面を主方位成分の１つとする圧延集合組織を実現させ、これによってノッチング後の曲げ加工性を顕著に改善させる。その曲げ加工性向上のメカニズムについては必ずしも明確ではないが、以下のようなことが考えられる。すなわち、板材の曲げ加工において、割れが発生する場合、曲げ加工部の外側の表層部が特に硬化し、表面割れはほとんど例外なく曲げ加工部の外側の板表面から約４５°の方向に沿って発生する。もし、ｆｃｃタイプである銅合金のすべり面｛１１１｝が板表面に対し約４５°（あるいは１３５°）方向に配向していれば、上記の割れは大幅に軽減されると考えられる。｛４２０｝面を板面に平行に持つ結晶粒では、４つの｛１１１｝面のうち２つが板面から約３９°の角度をもって存在している。つまり、その結晶粒は板面に対し４５°に近い角度で存在する複数のすべり面を有していることになる。前記（１）式を満たす圧延集合組織は｛４２０｝面を板面に平行にもつ結晶粒が存在する集合組織である。したがって、（１）式を満たす圧延集合組織を得ることにより、ノッチング後の曲げ加工において板面から４５°方向のすべりが生じやすくなり、割れ発生が顕著に抑止できるものと考えられる。   In the present invention, a rolling texture having the {420} plane as one of the main orientation components so as to satisfy the above formula (1) is realized, thereby significantly improving the bending workability after notching. The mechanism for improving the bending workability is not necessarily clear, but the following can be considered. That is, when a crack occurs in the bending process of the plate material, the surface layer part on the outside of the bent part is particularly hardened, and the surface crack is almost always along the direction of about 45 ° from the plate surface outside the bent part. appear. If the slip surface {111} of the copper alloy of the fcc type is oriented in the direction of about 45 ° (or 135 °) with respect to the plate surface, it is considered that the above cracks are greatly reduced. In a crystal grain having a {420} plane parallel to the plate surface, two of the four {111} planes are present at an angle of about 39 ° from the plate surface. That is, the crystal grains have a plurality of slip planes existing at an angle close to 45 ° with respect to the plate surface. The rolling texture satisfying the expression (1) is a texture in which crystal grains having {420} faces parallel to the plate surface exist. Therefore, by obtaining a rolling texture satisfying the expression (1), it is considered that slip in the 45 ° direction from the plate surface is likely to occur in bending after notching, and cracking can be remarkably suppressed.

このような圧延集合組織を得るためには、まず再結晶の段階で｛４２０｝を主方位の１つとする再結晶集合組織を得ておく。そのためには、特定の組成範囲に調整された合金を用いて、８５％以上の大きい圧延率で冷間圧延した後に溶体化処理することが肝要である。その後、冷間圧延を行うと次第に｛２２０｝を主方位成分とする圧延集合組織が発達していく。このとき、上記２種類の集合組織の中間的な結晶配向にコントロールすることによって上記（１）式を満たすようになり、高強度化とノッチング後の優れた曲げ加工性が一挙に達成される。その結晶配向のコントロールは、組成の調整と、前記（２）式を満たすような仕上げ冷間圧延によって可能となる。
以下、本発明を特定するための事項について説明する。 In order to obtain such a rolled texture, first, a recrystallized texture with {420} as one of the main orientations is obtained in the recrystallization stage. For that purpose, it is important to perform a solution treatment after cold rolling at a large rolling rate of 85% or more using an alloy adjusted to a specific composition range. Thereafter, when cold rolling is performed, a rolling texture having {220} as a main orientation component gradually develops. At this time, the above formula (1) is satisfied by controlling the intermediate crystal orientation between the two types of textures, and high bending strength and excellent bending workability after notching are achieved at once. The crystal orientation can be controlled by adjusting the composition and finish cold rolling that satisfies the above-mentioned formula (2).
Hereinafter, matters for specifying the present invention will be described.

〔合金組成〕
本発明ではＣｕ−Ｎｉ−Ｓｉ系銅合金を採用する。Ｃｕ−Ｎｉ−Ｓｉの３元系基本成分にＳｎ、Ｚｎ、Ｍｇ、その他の合金元素を添加した銅合金も、本明細書では包括的にＣｕ−Ｎｉ−Ｓｉ系銅合金と称している。 [Alloy composition]
In the present invention, a Cu—Ni—Si based copper alloy is employed. A copper alloy in which Sn, Zn, Mg, and other alloy elements are added to a Cu—Ni—Si ternary basic component is also collectively referred to as a Cu—Ni—Si copper alloy in this specification.

ＮｉおよびＳｉは、析出物を形成し、強度上昇および導電性・熱伝導度向上に寄与する。Ｎｉ含有量が０.７質量％未満またはＳｉ含有量が０.２質量％未満では、上記効果を有効に引き出すことが難しい。Ｎｉ含有量は１.２質量％以上を確保することがより好ましく、１.５質量％以上とすることが一層好ましい。またＳｉ含有量は０.３質量％以上を確保することがより好ましく、０.３５質量％以上とすることが一層好ましい。一方、Ｎｉ含有量が高すぎる場合やＳｉ含有量が高すぎる場合は粗大な析出物が生成しやすく、かつノッチングでの加工硬化が大きくなるので、ノッチング後の曲げ加工性がＬＤとＴＤともに低下しやすい。また、溶体化処理において後述する｛４２０｝を主方位成分とする再結晶集合組織を発達させることが難しくなり、最終的に曲げ加工性の優れたた板材を得ることが困難になる。このためＮｉ含有量の上限は２.５質量％に制限され、２.２質量％以下、あるいはさらに２.０質量％未満とする規制を設けてもよい。またＳｉ含有量の上限は０.７質量％に制限され、０.６質量％以下とすることがより好ましく、０.５質量％未満とすることが一層好ましい。   Ni and Si form precipitates and contribute to an increase in strength and an improvement in conductivity and thermal conductivity. When the Ni content is less than 0.7% by mass or the Si content is less than 0.2% by mass, it is difficult to effectively bring out the above effects. The Ni content is more preferably 1.2% by mass or more, and even more preferably 1.5% by mass or more. The Si content is more preferably 0.3% by mass or more, and still more preferably 0.35% by mass or more. On the other hand, if the Ni content is too high or the Si content is too high, coarse precipitates are likely to be formed, and work hardening at notching increases, so the bending workability after notching decreases for both LD and TD. It's easy to do. Further, it becomes difficult to develop a recrystallized texture having {420}, which will be described later, as a main orientation component in the solution treatment, and finally it is difficult to obtain a plate material excellent in bending workability. For this reason, the upper limit of the Ni content is limited to 2.5% by mass, and a regulation of 2.2% by mass or less, or even less than 2.0% by mass may be provided. The upper limit of Si content is limited to 0.7% by mass, more preferably 0.6% by mass or less, and still more preferably less than 0.5% by mass.

ＮｉとＳｉによって形成されるＮｉ−Ｓｉ系析出物はＮｉ₂Ｓｉを主体とする金属間化合物であると考えられる。ただし、合金中のＮｉおよびＳｉは時効処理によってすべてが析出物になるとは限らず、ある程度はＣｕマトリックス中に固溶した状態で存在する。固溶状態のＮｉおよびＳｉは、若干の強度上昇をもたらすものの析出状態と比べてその効果は小さく、また導電率を低下させる要因になる。このためＮｉとＳｉの含有量の比はできるだけ析出物Ｎｉ₂Ｓｉの組成比に近づけることが望ましい。したがって本発明では質量％で表したＮｉ／Ｓｉ比を３.５〜６.０の範囲に調整することが望ましく、３.５〜５.０とすることが一層好ましい。 The Ni—Si based precipitate formed by Ni and Si is considered to be an intermetallic compound mainly composed of Ni ₂ Si. However, Ni and Si in the alloy are not necessarily all precipitated by the aging treatment, and to some extent, exist in a solid solution state in the Cu matrix. Although Ni and Si in a solid solution state cause a slight increase in strength, the effect thereof is small as compared with a precipitated state, and it causes a decrease in conductivity. For this reason, it is desirable that the ratio of the Ni and Si contents be as close as possible to the composition ratio of the precipitate Ni ₂ Si. Therefore, in the present invention, it is desirable to adjust the Ni / Si ratio expressed in mass% to the range of 3.5 to 6.0, and more preferably 3.5 to 5.0.

Ｓｎは、固溶強化作用を有する。本発明ではこの固溶強化作用を析出強化および加工硬化と組み合わせることによって利用する。その作用を十分に発揮させるには、０.１質量％以上のＳｎ含有量を確保する必要がある。ただし、Ｓｎ含有量が１.２質量％を超えると導電率が著しく低下してしまう。このため、Ｓｎ含有量は０.１〜１.２質量％とする。特に０.２〜０.７質量％の範囲に調整することが一層好ましい。   Sn has a solid solution strengthening action. In the present invention, this solid solution strengthening action is utilized by combining it with precipitation strengthening and work hardening. In order to fully exhibit the effect | action, it is necessary to ensure Sn content of 0.1 mass% or more. However, when Sn content exceeds 1.2 mass%, electrical conductivity will fall remarkably. For this reason, Sn content shall be 0.1-1.2 mass%. In particular, it is more preferable to adjust to the range of 0.2-0.7 mass%.

Ｚｎは、はんだ付け性および強度を向上させる他、鋳造性を改善する効果もある。また、Ｚｎの添加には安価な黄銅スクラップが使用できるメリットがある。ただし、２.０質量％を超えると導電性や耐応力腐食割れ性の低下が問題になりやすい。このため、Ｚｎを添加する場合は２.０質量％以下の範囲で行う。上記の効果を十分に得るには０.１質量％以上のＺｎ含有量を確保することが望ましく、特に０.３〜１.０質量％の範囲に調整することが一層好ましい。   Zn improves solderability and strength, and also has an effect of improving castability. Further, the addition of Zn has an advantage that inexpensive brass scrap can be used. However, if it exceeds 2.0 mass%, a decrease in conductivity and stress corrosion cracking resistance tends to be a problem. For this reason, when adding Zn, it carries out in the range of 2.0 mass% or less. In order to sufficiently obtain the above effects, it is desirable to ensure a Zn content of 0.1% by mass or more, and it is particularly preferable to adjust the content to a range of 0.3 to 1.0% by mass.

Ｍｇは、Ｎｉ−Ｓｉ系析出物の粗大化を防止する作用を有する。また、耐応力緩和性を向上させる作用も有する。これらの作用を十分に発揮させるには０.０１質量％以上のＭｇ含有量を確保することが望ましい。ただし、Ｍｇ含有量が０.３質量％を超えると鋳造性、熱間加工性が著しく低下し、問題となりやすい。このため、Ｍｇを添加する場合は０.３質量％以下の範囲で行う。   Mg has an effect of preventing the coarsening of Ni—Si based precipitates. It also has an effect of improving stress relaxation resistance. In order to fully exhibit these actions, it is desirable to secure an Mg content of 0.01% by mass or more. However, if the Mg content exceeds 0.3% by mass, the castability and hot workability are remarkably lowered, which tends to cause a problem. For this reason, when adding Mg, it carries out in the range of 0.3 mass% or less.

その他の元素として、必要に応じてＣｏ、Ｃｒ、Ｂ、Ｐ、Ｆｅ、Ｚｒ、Ｔｉ、Ｍｎ等を含有させることができる。例えば、Ｃｏ、Ｃｒ、Ｂ、Ｐ、Ｆｅ、Ｚｒ、Ｔｉ、Ｍｎは合金強度をさらに高め、かつ応力緩和を小さくする作用を有する。Ｃｏ、Ｃｒ、Ｚｒ、Ｔｉ、Ｍｎは不可避的不純物として存在するＳ、Ｐｂなどと高融点化合物を形成しやすく、また、Ｂ、Ｐ、Ｚｒ、Ｔｉは鋳造組織の微細化効果を有し、熱間加工性の改善に寄与しうる。   As other elements, Co, Cr, B, P, Fe, Zr, Ti, Mn and the like can be contained as necessary. For example, Co, Cr, B, P, Fe, Zr, Ti, and Mn have the effect of further increasing the alloy strength and reducing the stress relaxation. Co, Cr, Zr, Ti, and Mn easily form a high melting point compound with S, Pb, etc. present as inevitable impurities, and B, P, Zr, and Ti have a refinement effect on the cast structure, It can contribute to the improvement of inter-workability.

Ｃｏ、Ｃｒ、Ｂ、Ｐ、Ｆｅ、Ｚｒ、Ｔｉ、Ｍｎの１種または２種以上を含有させる場合は、各元素の作用を十分に得るためにこれらの総量が０.０１質量％以上となるように含有させることが望ましい。ただし、総量が３質量％を超えると多量に含有すると、熱間または冷間加工性に悪い影響を与え、かつコストにも不利になる。したがって、その総量は３質量％以下の範囲とすることが望ましく、２質量％以下の範囲がより好ましく、１質量％以下の範囲がより一層好ましく、０.５質量％以下の範囲がさらに一層好ましい。   In the case where one or more of Co, Cr, B, P, Fe, Zr, Ti, and Mn are contained, the total amount of these elements becomes 0.01% by mass or more in order to sufficiently obtain the action of each element. It is desirable to contain. However, if the total amount exceeds 3% by mass, if it is contained in a large amount, the hot or cold workability is adversely affected, and the cost is disadvantageous. Accordingly, the total amount is preferably in the range of 3% by mass or less, more preferably in the range of 2% by mass or less, still more preferably in the range of 1% by mass or less, and still more preferably in the range of 0.5% by mass or less. .

〔結晶方位〕
Ｃｕ−Ｎｉ−Ｓｉ系銅合金は、後述する溶体化処理で得られるような｛４２０｝を主方位成分とする集合組織が強いほど、曲げ加工性がよくなる。ただし、高強度化を図るためには、仕上げ冷間圧延が不可欠である。冷間圧延率の増大にともない、｛２２０｝を主方位成分とする圧延集合組織が発達していく。そして、両者の中間的な組織状態を実現し、それによって「強度」と「ノッチング後の曲げ加工性」を高いレベルで維持することが可能である。しかもノッチング後の曲げ加工性は、曲げ軸がＴＤ、ＬＤいずれの方向についても同時に顕著な改善が実現される。つまり、異方性の小さいものが得られる。これは、｛４２０｝が板面に平行な結晶粒は、板面に対し４５°に近い角度で存在する複数のすべり面を有していること（前述）に起因して生じる効果であると推察される。 (Crystal orientation)
A Cu-Ni-Si-based copper alloy has better bending workability as the texture having {420} as a main orientation component as obtained by a solution treatment described later is stronger. However, finish cold rolling is indispensable for achieving high strength. As the cold rolling rate increases, a rolling texture with {220} as the main orientation component develops. Then, it is possible to realize an intermediate structure state between the two, thereby maintaining “strength” and “bending workability after notching” at a high level. In addition, the bendability after notching is significantly improved at the same time in both directions of the bending axis TD and LD. That is, a thing with small anisotropy is obtained. This is an effect caused by the fact that the crystal grains {420} are parallel to the plate surface have a plurality of sliding surfaces existing at an angle close to 45 ° with respect to the plate surface (described above). Inferred.

発明者らは種々検討の結果、その中間的な組織状態は、下記（１）式によって表すことができることを見出した。
０.１≦Ｉ｛４２０｝／Ｉ｛２２０｝≦０.５ ……（１）
ここで、Ｉ｛４２０｝およびＩ｛２２０｝はそれぞれ当該板材の板面における｛４２０｝結晶面および｛２２０｝結晶面のＸ線回折強度である。
Ｉ｛４２０｝／Ｉ｛２２０｝が大きすぎる場合は｛４２０｝を主方位成分とする再結晶集合組織の持つ性質が相対的に優勢であり、加工硬化不足により十分な強度が得られにくい。Ｉ｛４２０｝／Ｉ｛２２０｝が小さすぎる場合は｛２２０｝を主方位成分とする圧延晶集合組織の持つ性質が相対的に優勢であり、従来材のように強度が高く、曲げ加工性、特にノッチング後の曲げ加工性が悪くなる。 As a result of various studies, the inventors have found that the intermediate tissue state can be expressed by the following equation (1).
0.1 ≦ I {420} / I {220} ≦ 0.5 (1)
Here, I {420} and I {220} are the X-ray diffraction intensities of the {420} crystal plane and the {220} crystal plane on the plate surface of the plate material, respectively.
When I {420} / I {220} is too large, the recrystallized texture having {420} as the main orientation component is relatively dominant, and it is difficult to obtain sufficient strength due to insufficient work hardening. When I {420} / I {220} is too small, the properties of the rolled crystal texture having {220} as the main orientation component are relatively dominant, and the strength is high as in the conventional material, and the bending workability is high. In particular, the bending workability after notching deteriorates.

上記（１）式に替えて下記（１）’式を満たすことが一層好ましい。
０.２≦Ｉ｛４２０｝／Ｉ｛２２０｝≦０.４ ……（１）’ It is more preferable to satisfy the following expression (1) ′ instead of the above expression (1).
0.2 ≦ I {420} / I {220} ≦ 0.4 (1) ′

〔特性〕
電気・電子部品の更なる小型化、薄肉化に対応するには、素材である銅合金板材の引張強さは６５０ＭＰａ以上であることが好ましく、７００ＭＰａ以上であることが一層好ましい。時効硬化を利用して高強度化するため、この材料は時効処理された金属組織を有している。ノッチングを施さない場合の通常の曲げ加工性はＬＤ、ＴＤいずれにおいても９０°Ｗ曲げ試験における最小曲げ半径Ｒと板厚ｔの比Ｒ／ｔが１.０以下であることが好ましく、０.５以下であることが一層好ましい。ノッチング後の曲げ加工性は少なくとも曲げ軸がＴＤとなる９０°Ｗ曲げ試験において曲げ半径Ｒ＝０ｍｍで割れがないこと必要であるが、後述の製造工程に従えば、曲げ軸がＬＤとなる同様の９０°Ｗ曲げ試験でも割れが生じない異方性の小さいものが得られる。 〔Characteristic〕
In order to cope with further downsizing and thinning of electric / electronic parts, the tensile strength of the copper alloy sheet material is preferably 650 MPa or more, and more preferably 700 MPa or more. In order to increase the strength by using age hardening, this material has an age-treated metal structure. The normal bending workability without notching is preferably such that the ratio R / t of the minimum bending radius R to the sheet thickness t in the 90 ° W bending test is 1.0 or less in both LD and TD. More preferably, it is 5 or less. Bending workability after notching requires at least a bending radius R = 0 mm and no cracking in a 90 ° W bending test in which the bending axis becomes TD. However, according to the manufacturing process described later, the bending axis becomes LD. Even in the 90 ° W bending test, a small anisotropy with no cracks is obtained.

〔製造工程〕
以上のような本発明の銅合金板材は、コストアップをもたらす特別な製造工程を必要とすることなく、例えば以下のような一般な製造工程により作ることができる。
「溶解・鋳造→熱間圧延→冷間圧延→溶体化処理→中間冷間圧延→時効処理→仕上げ冷間圧延→加熱処理」
ただし、後述のように製造条件のコントロールが必要である。なお、上記工程中には記載していないが、熱間圧延後には必要に応じて面削が行われ、熱処理後には必要に応じて酸洗、研磨、あるいはさらに脱脂が行われる。以下、各工程について説明する。 〔Manufacturing process〕
The copper alloy sheet material of the present invention as described above can be produced by, for example, the following general production process without requiring a special production process that brings about an increase in cost.
“Melting / Casting → Hot Rolling → Cold Rolling → Solution Treatment → Intermediate Cold Rolling → Aging Treatment → Finish Cold Rolling → Heat Treatment”
However, it is necessary to control the manufacturing conditions as described later. Although not described in the above process, chamfering is performed as necessary after hot rolling, and pickling, polishing, or further degreasing is performed as necessary after heat treatment. Hereinafter, each step will be described.

〔溶解・鋳造〕
一般的な銅合金の溶製方法に従うことができる。連続鋳造、半連続鋳造等により鋳片を製造すればよい。 [Melting / Casting]
A general copper alloy melting method can be followed. The slab may be manufactured by continuous casting, semi-continuous casting, or the like.

〔熱間圧延〕
鋳片を熱間加工することで鋳造過程で生じる晶出相を消失させると同時に、再結晶によって鋳造組織を破壊し再結晶粒組織の均一化を図る。この熱間圧延は析出物の固溶温度域で行うことが望ましい。熱間圧延終了後は直ちに水冷等により急冷することが望ましい。６５０℃未満の温度域ではＮｉとＳｉの粗大な化合物の生成により熱間割れが生じやすくなるので９５０〜６５０℃の範囲で熱間圧延を行い、最終パス終了後に水冷することが好ましい。熱間圧延率は概ね６５〜９０％とすればよい。熱間加工後は必要に応じて面削や酸洗を行うことができる。 (Hot rolling)
By hot working the slab, the crystallization phase generated in the casting process disappears, and at the same time, the cast structure is destroyed by recrystallization to make the recrystallized grain structure uniform. This hot rolling is desirably performed in the solid solution temperature range of the precipitate. It is desirable to quench immediately after the hot rolling by water cooling or the like. In the temperature range below 650 ° C., hot cracking is likely to occur due to the formation of a coarse compound of Ni and Si. Therefore, it is preferable to perform hot rolling in the range of 950 to 650 ° C. and water-cool after the final pass. The hot rolling rate may be approximately 65 to 90%. After hot working, chamfering or pickling can be performed as necessary.

〔冷間圧延〕
溶体化処理前に行う冷間圧延では圧延率を８５％以上とすることが重要であり、９０％以上とすることがより好ましい。このような高い圧延率で加工された材料に対し、次工程で溶体化処理を施すことにより、｛４２０｝を主方位成分とする再結晶集合組織を得ることができる。この冷間圧延率が低すぎると上記再結晶集合組織の形成が不十分となり、本発明の目的を達成することが難しくなる。すなわち、再結晶集合組織は再結晶前の冷間圧延率に依存する。具体的には、｛４２０｝の方位関係を持つ結晶配向は、冷間圧延率が６０％以下の領域ではほとんど生成せず、約６０〜８０％の領域では冷間圧延率の増加に伴って漸増し、冷間圧延率が約８０％を超えると急激な増加に転じる。上記方位関係が十分に優勢な結晶配向を得るには８５％以上の冷間圧延率を確保する必要があり、更に９０％以上は望ましい。なお、冷間圧延率の上限はミルパワー等により必然的に制約を受けるので、特に規定する必要はないが、概ね９８％以下で良好な結果を得やすい。
熱間圧延後、溶体化処理前に、中間焼鈍を挟んで複数回の冷間圧延を実施する場合は、溶体化処理前に行われる最後の中間焼鈍の後に実施される冷間圧延での冷間圧延率を上記のように調整する。 (Cold rolling)
In the cold rolling performed before the solution treatment, it is important that the rolling rate is 85% or more, and more preferably 90% or more. A recrystallized texture having {420} as the main orientation component can be obtained by subjecting the material processed at such a high rolling rate to a solution treatment in the next step. If this cold rolling rate is too low, the formation of the recrystallized texture becomes insufficient, making it difficult to achieve the object of the present invention. That is, the recrystallization texture depends on the cold rolling rate before recrystallization. Specifically, the crystal orientation having the orientation relationship of {420} is hardly generated in the region where the cold rolling rate is 60% or less, and with the increase in the cold rolling rate in the region of about 60 to 80%. It gradually increases, and when the cold rolling rate exceeds about 80%, it starts to increase rapidly. In order to obtain a crystal orientation in which the orientation relationship is sufficiently dominant, it is necessary to secure a cold rolling rate of 85% or more, and more preferably 90% or more. The upper limit of the cold rolling rate is inevitably restricted by the mill power or the like, so it is not necessary to define it in particular, but good results are likely to be obtained at approximately 98% or less.
When performing cold rolling multiple times after the intermediate annealing before the solution treatment after the hot rolling, the cold rolling in the cold rolling performed after the last intermediate annealing performed before the solution treatment. The rolling ratio is adjusted as described above.

〔溶体化処理〕
ここでの溶体化処理は、「溶質元素のマトリックス中への再固溶」および「再結晶化」という２つの目的を兼ねる熱処理である。８５％以上の高い圧延率で加工された材料を対象とすることにより、溶体化処理後には｛４２０｝を優先方位とする再結晶集合組織が得られると同時に、｛２２０｝方位の生成が抑制される。この溶体化処理は、再結晶粒径が１５〜６０μｍとなるように温度・時間を調整して行うことが望ましく、２０〜４０μｍとなるように調整することが一層好ましい。再結晶粒径が微細になりすぎると再結晶集合組織が弱くなることにより、仕上げ圧延時時に圧延集合組織が優勢となりやすく、曲げ加工性の改善が難しくなる。ただし、溶体化処理温度を過度に高めないことが重要である。具体的には、７００〜８００℃未満、好ましくは７００〜７８０℃の炉温で１０ｓｅｃ〜１０ｍｉｎの加熱条件が採用できる。溶体化処理温度が高すぎると｛２００｝方位が優勢となり｛４２０｝を優先方位とする再結晶集合組織が得られにくい場合がある。また、結晶粒径が粗大化しやすく、曲げ加工性の低下を招きやすい。一方、温度が低すぎると再結晶が不完全で溶質元素の固溶も不十分となり、最終的に曲げ加工性の優れた高強度材を得ることは困難となる。本発明ではＮｉおよびＳｉの含有量上限を上記のように厳しく規制しているので、８００℃未満あるいは７８０℃以下といった低めの溶体化処理温度でＮｉ₂Ｓｉ相を十分に消失させることができる。 [Solution treatment]
The solution treatment here is a heat treatment that serves the two purposes of “re-solution of solute elements in the matrix” and “recrystallization”. By targeting materials processed at a high rolling rate of 85% or more, a recrystallized texture with {420} as the preferred orientation is obtained after solution treatment, and at the same time, the generation of {220} orientation is suppressed. Is done. This solution treatment is preferably performed by adjusting the temperature and time so that the recrystallized grain size is 15 to 60 μm, and more preferably 20 to 40 μm. If the recrystallized grain size becomes too fine, the recrystallized texture becomes weak, so that the rolled texture tends to become dominant at the time of finish rolling, and it becomes difficult to improve the bending workability. However, it is important not to increase the solution treatment temperature excessively. Specifically, heating conditions of 10 sec to 10 min can be adopted at a furnace temperature of 700 to less than 800 ° C., preferably 700 to 780 ° C. If the solution treatment temperature is too high, the {200} orientation is dominant, and it may be difficult to obtain a recrystallized texture having {420} as the preferred orientation. Further, the crystal grain size is likely to be coarsened, and bending workability is liable to be lowered. On the other hand, if the temperature is too low, recrystallization is incomplete and solute elements are not sufficiently dissolved, and it becomes difficult to finally obtain a high-strength material excellent in bending workability. In the present invention, the upper limit of the Ni and Si contents is strictly regulated as described above, so that the Ni ₂ Si phase can be sufficiently lost at a lower solution treatment temperature of less than 800 ° C. or 780 ° C. or less.

〔中間冷間圧延〕
続いて、０〜５０％の圧延率で冷間圧延を行う。この段階での冷間圧延は次工程の時効処理中の析出を促進する効果があり、必要な特性（導電率、硬さ）を引き出すための時効時間を短くすることができる。この冷間圧延によって、｛２２０｝を主方位成分とする集合組織が発達していくが、５０％以下の冷間圧延率の範囲では、まだ十分に｛４２０｝面を板面に平行にもつ結晶粒も残存する。特に、この冷間圧延での圧延率は、時効処理後に行う後述の仕上げ冷間圧での圧延率とうまく組合せることにより、最終的な高強度化とノッチング後の曲げ加工性改善に寄与する。この段階の冷間圧延は圧延率５０％以下で行う必要があり、０〜３５％とすることがより好ましい。圧延率が高過ぎると続く時効処理で析出が不均一に発生して過時効になりやすく、また前記（１）式を満たすような理想的な結晶配向が得られにくくなる。
圧延率がゼロである場合は、溶体化処理後に中間の冷間圧延を行わず、直接時効処理に供することを意味する。本発明の銅合金板材は、生産性を向上するために、この段階での冷間圧延工程を省略してもよい。 (Intermediate cold rolling)
Subsequently, cold rolling is performed at a rolling rate of 0 to 50%. Cold rolling at this stage has the effect of promoting precipitation during the aging treatment in the next step, and the aging time for extracting necessary properties (conductivity and hardness) can be shortened. By this cold rolling, a texture having {220} as the main orientation component develops. However, in the range of the cold rolling rate of 50% or less, the {420} plane is still sufficiently parallel to the plate surface. Crystal grains also remain. In particular, the rolling ratio in this cold rolling contributes to the final increase in strength and the improvement in bending workability after notching by combining well with the rolling ratio at the finishing cold pressure described later after the aging treatment. . Cold rolling at this stage needs to be performed at a rolling rate of 50% or less, and more preferably 0 to 35%. If the rolling rate is too high, precipitation will occur non-uniformly in the subsequent aging treatment, and overaging will tend to occur, and it will be difficult to obtain an ideal crystal orientation that satisfies the formula (1).
When the rolling rate is zero, it means that the intermediate cold rolling is not performed after the solution treatment and the aging treatment is directly performed. In order to improve productivity, the copper alloy sheet of the present invention may omit the cold rolling process at this stage.

〔時効処理〕
続いて、時効処理を施す。時効処理では、当該合金の導電性と強度の向上に有効な条件の中で、あまり温度を上げすぎないようにする。時効処理温度が高くなりすぎると溶体化処理によって発達させた｛４２０｝を優先方位とする結晶配向が弱められ、結果的に十分な曲げ加工性改善効果が得られない場合がある。具体的には材温が４００〜５００℃となる温度で行うことが望ましく、４２０〜４８０℃の範囲が一層好ましい。時効処理時間は概ね１〜１０ｈ程度で良好な結果が得られる。 [Aging treatment]
Subsequently, an aging treatment is performed. In the aging treatment, the temperature is not excessively raised under conditions effective for improving the conductivity and strength of the alloy. If the aging temperature is too high, the crystal orientation with {420} as the preferred orientation developed by the solution treatment is weakened, and as a result, sufficient bending workability improvement effect may not be obtained. Specifically, it is desirable to carry out at a temperature at which the material temperature is 400 to 500 ° C, and a range of 420 to 480 ° C is more preferable. An aging treatment time is about 1 to 10 hours, and good results are obtained.

〔仕上げ冷間圧延〕
この仕上げ冷間圧延では、強度レベルの向上を図るとともに、｛２２０｝を主方位成分とする圧延集合組織を発達させていく。仕上げ冷間圧延の圧延率が低すぎると強度上昇効果が十分に得られない。逆に圧延率が高すぎると｛２２０｝方位の圧延集合組織が相対的に優勢となりすぎ、強度とノッチング後の曲げ加工性が高レベルで両立された中間的な結晶配向が実現できない。 (Finish cold rolling)
In this finish cold rolling, the strength level is improved and a rolling texture having {220} as the main orientation component is developed. If the rolling rate of finish cold rolling is too low, the effect of increasing the strength cannot be obtained sufficiently. On the other hand, if the rolling rate is too high, the rolling texture in the {220} orientation becomes relatively dominant, and an intermediate crystal orientation in which strength and bending workability after notching are compatible at a high level cannot be realized.

仕上げ圧延率は１０％以上とすることが必要である。ただし、仕上げ冷間圧延率の上限については、時効処理前に行った中間冷間圧延の寄与分を考慮しなければならない。発明者らの詳細な研究の結果、その上限は上記の中間冷間圧延率との合計で溶体化処理から最終工程まで板厚の減少率が６５％を超えないように設定する必要があることがわかった。すなわち、下記（２）式を満たすように仕上げ冷間圧延を行う。
１０≦ε₂≦（６５−ε₁）／（１００−ε₁）×１００ ……（２）
ここで、ε₁は中間冷間圧延率（％）、ε₂は仕上げ冷間圧延率（％）である。
最終的な板厚としては概ね０.０５〜１.０ｍｍが適用され、０.０８〜０.５ｍｍとすることが一層好ましい。 The finish rolling ratio needs to be 10% or more. However, for the upper limit of the finish cold rolling rate, the contribution of the intermediate cold rolling performed before the aging treatment must be taken into account. As a result of detailed studies by the inventors, the upper limit must be set so that the reduction rate of the sheet thickness does not exceed 65% from the solution treatment to the final step in total with the above-mentioned intermediate cold rolling rate. I understood. That is, finish cold rolling is performed so as to satisfy the following expression (2).
10 ≦ ε ₂ ≦ (65−ε ₁ ) / (100−ε ₁ ) × 100 (2)
Here, ε ₁ is the intermediate cold rolling rate (%), and ε ₂ is the finish cold rolling rate (%).
As the final plate thickness, approximately 0.05 to 1.0 mm is applied, and 0.08 to 0.5 mm is more preferable.

〔加熱処理（低温焼鈍）〕
仕上げ冷間圧延後には、板条材の残留応力の低減、ばね限界値と耐応力緩和特性向上を目的として、低温焼鈍を施すことができる。加熱温度は１５０〜５５０℃となるように設定することが望ましい。これにより板材内部の残留応力が低減され、強度低下をほとんど伴わずに曲げ加工性と破断伸びを上昇させることができる。また、導電率を上昇させる効果もある。この加熱温度が高すぎると短時間で軟化し、バッチ式でも連続式でも特性のバラツキが生じやすくなる。逆に加熱温度が低すぎると上記特性の改善効果が十分に得られない。加熱時間は５ｓｅｃ以上確保することが望ましく、通常１ｈ以内の範囲で良好な結果が得られる。 [Heat treatment (low temperature annealing)]
After the finish cold rolling, low-temperature annealing can be performed for the purpose of reducing the residual stress of the strip material and improving the spring limit value and stress relaxation resistance. The heating temperature is desirably set to 150 to 550 ° C. As a result, the residual stress inside the plate material is reduced, and bending workability and elongation at break can be increased with almost no decrease in strength. It also has the effect of increasing the conductivity. If this heating temperature is too high, it softens in a short time, and variations in characteristics are likely to occur in both batch and continuous systems. Conversely, if the heating temperature is too low, the effect of improving the above characteristics cannot be obtained sufficiently. It is desirable to secure a heating time of 5 sec or more, and good results are usually obtained within a range of 1 h.

表１に示す銅合金を溶製し、縦型連続鋳造機を用いて鋳造した。得られた鋳片を９５０℃に加熱し、９５０〜６５０℃の温度範囲で熱間圧延を行うことにより厚さ１０ｍｍの板にし、その後急冷（水冷）した。熱間圧延後、表層の酸化層を機械研磨により除去（面削）した。次いで、種々の圧延率で冷間圧延を行った後、溶体化処理に供した。溶体化処理では圧延板表面における平均結晶粒径（ＪＩＳ Ｈ０５０１の線分法）が２５μｍ超え〜４０μｍとなるように保持温度を合金組成に応じて７００〜７８０℃の範囲内で調整した。保持時間は１０ｓｅｃ〜１０ｍｉｍの範囲とした。続いて、上記溶体化処理後の板材に対して、一部のものを除き中間冷間圧延を施し、次いで時効処理を施した。時効処理温度は材温４５０℃とし、時効時間は合金組成に応じて４５０℃の時効で硬さがピークになる時間に調整した。このような合金組成に応じて最適な溶体化処理条件や時効処理時間は予備実験により把握してある。次いで、種々の圧延率で仕上げ冷間圧延を行い、その後、４００℃の炉中に５ｍｉｎ装入する加熱処理（低温焼鈍）を施すことによって供試材を得た。なお、必要に応じて途中で面削を行い、供試材の板厚は０.２ｍｍに揃えた。   The copper alloys shown in Table 1 were melted and cast using a vertical continuous casting machine. The obtained slab was heated to 950 ° C., and hot-rolled in a temperature range of 950 to 650 ° C. to obtain a plate having a thickness of 10 mm, and then rapidly cooled (water cooled). After hot rolling, the surface oxide layer was removed (faced) by mechanical polishing. Next, after cold rolling at various rolling rates, it was subjected to a solution treatment. In the solution treatment, the holding temperature was adjusted in the range of 700 to 780 ° C. according to the alloy composition so that the average crystal grain size (line segment method of JIS H0501) on the rolled sheet surface exceeded 25 μm to 40 μm. The holding time was in the range of 10 sec to 10 mim. Subsequently, the plate material after the solution treatment was subjected to intermediate cold rolling except for a part, and then subjected to an aging treatment. The aging treatment temperature was adjusted to a material temperature of 450 ° C., and the aging time was adjusted to a time when the hardness peaked at 450 ° C. according to the alloy composition. The optimum solution treatment conditions and aging treatment time according to such an alloy composition have been grasped by preliminary experiments. Next, finish cold rolling was performed at various rolling rates, and then a test material was obtained by performing heat treatment (low-temperature annealing) for 5 minutes in a 400 ° C. furnace. If necessary, chamfering was performed in the middle, and the thickness of the specimen was adjusted to 0.2 mm.

各供試材から試料を採取し、Ｘ線回折強度、導電率、引張強さ、破断伸び、曲げ加工性、ノッチング後の曲げ加工性を以下の方法で調べた。   Samples were collected from each test material and examined for X-ray diffraction strength, electrical conductivity, tensile strength, elongation at break, bending workability, and bending workability after notching by the following methods.

〔Ｘ線回折強度〕
供試材の表面（圧延面）を＃１５００耐水ペーパー研磨仕上げとした試料を準備し、Ｘ線回折装置（ＸＲＤ）を用いて、Ｍｏ−Ｋα線、管電圧２０ｋＶ、管電流２ｍＡの条件で、前記試料の板面（圧延面）について｛２２０｝面および｛４２０｝面の反射回折面強度を測定し、前記（１）式中に示されるＸ線回折強度比を求めた。 [X-ray diffraction intensity]
Prepare a sample with the surface (rolled surface) of the test material # 1500 water-resistant paper polished, using an X-ray diffractometer (XRD), under the conditions of Mo-Kα rays, tube voltage 20 kV, tube current 2 mA, With respect to the plate surface (rolled surface) of the sample, the reflection diffraction surface intensities of the {220} plane and the {420} plane were measured, and the X-ray diffraction intensity ratio shown in the equation (1) was determined.

〔導電率〕
ＪＩＳ Ｈ０５０５に従って各供試材の導電率を測定した。
〔引張強さ、破断伸び〕
各供試材からＬＤの引張試験片（ＪＩＳ ５号）を採取し、各方向ｎ＝３でＪＩＳ Ｚ２２４１に準拠した引張試験行い、ｎ＝３の平均値によって引張強さと破断伸びを求めた。 〔conductivity〕
The electrical conductivity of each test material was measured according to JIS H0505.
[Tensile strength, elongation at break]
An LD tensile test piece (JIS No. 5) was collected from each test material, and subjected to a tensile test in accordance with JIS Z2241 in each direction n = 3, and the tensile strength and elongation at break were determined by the average value of n = 3.

〔通常の曲げ加工性〕
各供試材から長手方向がＬＤおよびＴＤの曲げ試験片（幅１０ｍｍ）を採取し、ＪＩＳ Ｈ３１１０に準拠した９０°Ｗ曲げ試験を行った。試験後の試験片について曲げ加工部の表面および断面を光学顕微鏡にて１００倍の倍率で観察することにより、割れが発生しない最小曲げ半径Ｒを求め、これを供試材の板厚ｔで除することによりＬＤ、ＴＤそれぞれのＲ／ｔ値を求めた。各供試材のＬＤ、ＴＤともｎ＝３で実施し、ｎ＝３のうち最も悪い結果となった試験片の成績を採用してＲ／ｔ値を表示した。 [Normal bending workability]
Bending test pieces (width 10 mm) having a longitudinal direction of LD and TD were sampled from each test material, and a 90 ° W bending test based on JIS H3110 was performed. By observing the surface and cross section of the bent portion of the test piece after the test with an optical microscope at a magnification of 100 times, the minimum bending radius R at which no crack is generated is obtained, and this is divided by the thickness t of the specimen. Thus, R / t values of LD and TD were obtained. The LD and TD of each test material were carried out with n = 3, and the result of the test piece with the worst result among n = 3 was adopted to display the R / t value.

〔ノッチング後の曲げ加工性〕
各供試材から長手方向がＬＤおよびＴＤの短冊形試料（幅１０ｍｍ）を採取し、図１に示す断面形状のノッチ形成治具（凸部先端のフラット面の幅０.１ｍｍ、両側面角度４５°）を用いて、１５ｋＮの荷重を付与することにより試料幅いっぱいにノッチを形成した（図２参照）。ノッチの方向（すなわち溝に対して平行な方向）は、試料の長手方向に対して直角方向である。このようにして準備したノッチ付き曲げ試験片のノッチ深さを実測したところ、板厚の１／４程度であった。 [Bendability after notching]
A strip-shaped sample (width 10 mm) whose longitudinal direction is LD and TD is taken from each test material, and a notch forming jig having a cross-sectional shape shown in FIG. 1 (width of flat surface of convex tip 0.1 mm, angle on both sides) 45 °), a notch was formed to the full width of the sample by applying a load of 15 kN (see FIG. 2). The direction of the notch (ie, the direction parallel to the groove) is a direction perpendicular to the longitudinal direction of the sample. When the notch depth of the notched bending test piece prepared in this way was measured, it was about 1/4 of the plate thickness.

これらのノッチ付き曲げ試験片について、ＪＩＳ Ｈ３１１０に準拠した９０°Ｗ曲げ試験により「ノッチ曲げ試験」を実施した。このとき、下型の中央突起部先端のＲを０ｍｍとした治具を用い、前記ノッチ付き曲げ試験片を、ノッチ形成面が下向きになり、前記下型の中央突起部先端がノッチ部分に合致するようにセットして９０°Ｗ曲げ試験を行った。
試験後の試験片について曲げ加工部の表面および断面を光学顕微鏡にて１００倍の倍率で観察することにより、割れの有無を判断し、割れが認められないものを「〇」、割れが認められたものを「×」と表示した。なお、曲げ加工部で破断したものは「破」と表示した。各供試材のＬＤ、ＴＤともｎ＝３で実施し、ｎ＝３のうち最も悪い結果となった試験片の成績を採用して「○」、「×」、「破」の評価を行った。
製造条件と、これらの結果を表２に示す。なお、表２中、通常の曲げ加工性およびノッチング後の曲げ加工性の欄において、ＬＤおよびＴＤは曲げ試験片の長手方向を意味する。 About these bending test pieces with a notch, the "notch bending test" was implemented by the 90 degree W bending test based on JISH3110. At this time, using a jig with R at the center protrusion tip of the lower die set to 0 mm, the notched bending test piece has the notch forming surface facing downward, and the tip of the center protrusion portion of the lower die matches the notch portion. 90 ° W bending test was performed.
By observing the surface and cross section of the bent part with a magnification of 100 times with an optical microscope, the presence or absence of cracks was judged on the test piece after the test. "X" was displayed. In addition, what fractured | ruptured in the bending process part was displayed as "break". Each test material LD and TD were carried out with n = 3, and the results of the test piece with the worst result among n = 3 were adopted to evaluate “○”, “×”, and “Break”. It was.
The production conditions and the results are shown in Table 2. In Table 2, in the columns of normal bending workability and bending workability after notching, LD and TD mean the longitudinal direction of the bending test piece.

表２から判るように、本発明例のものはいずれもＸ線回折強度比が（１）式を満たす結晶配向を有し、引張強さが７００ＭＰａ以上という高強度を呈するとともに、Ｒ／ｔ値がＬＤ、ＴＤとも０.５以下という優れた曲げ加工性を有する。さらに、ノッチング後の曲げ加工性について、９０°Ｗ曲げ試験Ｒ／ｔ＝０での厳しい曲げを行ったにもかかわらず、割れが生じなかった。   As can be seen from Table 2, all of the examples of the present invention have a crystal orientation in which the X-ray diffraction intensity ratio satisfies the formula (1), a high tensile strength of 700 MPa or more, and an R / t value. However, both LD and TD have excellent bending workability of 0.5 or less. Furthermore, with respect to the bending workability after notching, no cracking occurred even though severe bending was performed at 90 ° W bending test R / t = 0.

これに対し、比較例Ｎｏ.２１はＮｉとＳｉの含有量が低すぎたことにより、析出物の生成が少なく、強度レベルが低かった。Ｎｏ.２２はＮｉとＳｉの含有量が高すぎたことにより、製造条件が適正であっても｛４２０｝を主方位成分とする結晶粒の相対量が不十分となり、引張強さは高いものの、通常の曲げ加工性およびノッチング後の曲げ加工性が非常に悪かった。Ｎｏ.２３はＮｏ.２２と同一組成のものについて、曲げ加工性の向上を図るべく仕上げ冷間圧延を省略した例である。この場合、Ｎｏ.２２に比べ通常の曲げ加工性は改善されたが、｛４２０｝を主方位成分とする結晶粒の相対量が不十分となったことにより（１）式を満たす結晶配向が得られず、ノッチング後の曲げ加工性は改善されなかった。   On the other hand, Comparative Example No. 21 had a low Ni and Si content, resulting in less generation of precipitates and a low strength level. In No. 22, the contents of Ni and Si were too high, but even if the production conditions were appropriate, the relative amount of crystal grains having {420} as the main orientation component was insufficient, and the tensile strength was high. The normal bendability and the bendability after notching were very poor. No. 23 is an example in which finish cold rolling is omitted for the same composition as No. 22 in order to improve bending workability. In this case, the normal bending workability was improved as compared with No. 22, but the crystal orientation satisfying the formula (1) was not obtained because the relative amount of crystal grains having {420} as the main orientation component became insufficient. The bending workability after notching was not improved.

比較例Ｎｏ.２４と２５は溶体化処理前の冷間圧延率が低すぎたことにより溶体化処理で｛４２０｝を主方位成分とする再結晶集合組織が十分に発達せず、最終的に（１）式を満たす結晶配向が得られなかった。仕上げ圧延率を調整しても、引張強さとノッチング後の曲げ加工性両立できなかった例である。比較例Ｎｏ.２６は仕上げ圧延率が低すぎたことにより強度レベルが低かった。比較例Ｎｏ.２７は仕上げ圧延率が（２）式の上限値を超えたことにより（１）式を満たす結晶配向が得られず、引張強さが高いものの、通常の曲げ加工性およびノッチング後の曲げ加工性に劣った。Ｎｏ.２８は溶体化処理と時効処理の間の中間冷間圧延率が高すぎたことにより、仕上げ圧延率を低くしても（１）式を満たす結晶配向が得られず、結局、過時効の発生により析出物が粗大化し、引張強さ、通常の曲げ加工性、およびノッチング後の曲げ加工性に劣った。   In Comparative Examples No. 24 and No. 25, the cold rolling rate before the solution treatment was too low, so that the recrystallization texture having {420} as the main orientation component did not sufficiently develop in the solution treatment. A crystal orientation satisfying the formula (1) was not obtained. This is an example in which even if the finish rolling ratio is adjusted, the tensile strength and the bending workability after notching cannot be achieved. Comparative Example No. 26 had a low strength level because the finish rolling rate was too low. In Comparative Example No. 27, although the finish rolling ratio exceeded the upper limit of the formula (2), the crystal orientation satisfying the formula (1) was not obtained and the tensile strength was high, but after normal bending workability and notching Inferior in bending workability. In No. 28, since the intermediate cold rolling rate between the solution treatment and the aging treatment was too high, a crystal orientation satisfying the formula (1) could not be obtained even if the finish rolling rate was lowered. As a result, the precipitates became coarse, and the tensile strength, normal bending workability, and bending workability after notching were inferior.

ノッチ形成治具の断面形状を示した図。The figure which showed the cross-sectional shape of the notch formation jig | tool. ノッチングの方法を模式的に示した図。The figure which showed the method of notching typically. ノッチ付き曲げ試験片のノッチ形成部付近の断面形状を模式的に示した図。The figure which showed typically the cross-sectional shape of the notch formation part vicinity of a bending test piece with a notch.

Claims (9)

質量％で、Ｎｉ：０.７〜２.５％、Ｓｉ：０.２〜０.７％、Ｓｎ：０.１〜１.２％、残部実質的にＣｕの組成を有し、下記（１）式を満たす結晶配向を有する銅合金板材。
０.１≦Ｉ｛４２０｝／Ｉ｛２２０｝≦０.５ ……（１）
ここで、Ｉ｛４２０｝およびＩ｛２２０｝はそれぞれ当該板材の板面における｛４２０｝結晶面および｛２２０｝結晶面のＸ線回折強度である。 In mass%, Ni has a composition of 0.7 to 2.5%, Si: 0.2 to 0.7%, Sn: 0.1 to 1.2%, and the balance substantially Cu. 1) A copper alloy sheet having a crystal orientation satisfying the formula.
0.1 ≦ I {420} / I {220} ≦ 0.5 (1)
Here, I {420} and I {220} are the X-ray diffraction intensities of the {420} crystal plane and the {220} crystal plane on the plate surface of the plate material, respectively. 板面において圧延方向に対し平行方向をＬＤ、直角方向をＴＤと呼ぶとき、当該板材から長手方向がＬＤになるように採取された短冊形試料の片面に、図１に示す断面形状のノッチ形成治具を用いて、深さが板厚の１／８〜１／２、方向がＴＤのノッチを試料幅いっぱいに形成したノッチ付き曲げ試験片について、下記のノッチ曲げ試験を実施したとき、当該試験片表面に割れが認められない曲げ加工性を有する請求項１に記載の銅合金板材。
〔ノッチ曲げ試験〕
ＪＩＳ Ｈ３１１０に規定される９０°Ｗ曲げ試験において下型の中央突起部先端のＲを０ｍｍとした治具を用意し、前記ノッチ付き曲げ試験片を、ノッチ形成面が下向きになり、前記下型の中央突起部先端がノッチ部分に合致するようにセットして９０°Ｗ曲げ試験を行う。 When the parallel direction to the rolling direction on the plate surface is called LD and the perpendicular direction is called TD, a notch having a cross-sectional shape shown in FIG. 1 is formed on one side of a strip sample taken from the plate material so that the longitudinal direction becomes LD. When the following notch bending test was performed on a notched bending test piece in which a notch having a depth of 1/8 to 1/2 of the plate thickness and a direction of TD was formed using the jig to fill the sample width, The copper alloy sheet according to claim 1, which has a bending workability in which no cracks are observed on the surface of the test piece.
[Notch bending test]
In the 90 ° W bending test specified in JIS H3110, a jig was prepared in which the R at the tip of the central projection of the lower die was 0 mm. The notched bending test piece was placed with the notch forming surface facing downward. A 90 ° W bend test is performed by setting the tip of the central protrusion of the core to match the notch. 当該板材から長手方向がＴＤになるように採取された短冊形試料の片面に、図１に示す断面形状のノッチ形成治具を用いて、深さが板厚の１／８〜１／２、方向がＬＤのノッチを試料幅いっぱいに形成したノッチ付き曲げ試験片について、前記のノッチ曲げ試験を実施したとき、当該試験片表面に割れが認められない曲げ加工性を有する請求項２に記載の銅合金板材。   Using a notch forming jig having a cross-sectional shape shown in FIG. 1 on one side of a strip sample collected so that the longitudinal direction is TD from the plate material, the depth is 1/8 to 1/2 of the plate thickness, 3. The bending test piece according to claim 2, wherein when the notch bending test is performed on a notched bending test piece in which a notch whose direction is LD is formed to the full width of the sample, no crack is observed on the surface of the test piece. Copper alloy sheet. さらにＺｎ：２.０％以下を含む組成を有する請求項１〜３のいずれかに記載の銅合金板材。   Furthermore, the copper alloy board | plate material in any one of Claims 1-3 which has a composition containing Zn: 2.0% or less. さらにＭｇ：０.３％以下を含む組成を有する請求項１〜４のいずれかに記載の銅合金板材。   Furthermore, the copper alloy board | plate material in any one of Claims 1-4 which has a composition containing Mg: 0.3% or less. さらにＣｏ、Ｃｒ、Ｂ、Ｐ、Ｆｅ、Ｚｒ、Ｔｉ、Ｍｎの１種以上を合計３％以下の範囲で含む組成を有する請求項１〜５のいずれかに記載の銅合金板材。   Furthermore, the copper alloy board | plate material in any one of Claims 1-5 which has a composition which contains 1 or more types of Co, Cr, B, P, Fe, Zr, Ti, and Mn in the range of 3% or less in total. 時効処理を経た組織を有し、引張強さが７００ＭＰａ以上である請求項１〜６のいずれかに記載の銅合金板材。   The copper alloy sheet according to any one of claims 1 to 6, which has a structure subjected to an aging treatment and has a tensile strength of 700 MPa or more. 組成調整された銅合金材料に対し、圧延率８５％以上の冷間圧延、７００〜８００℃未満の溶体化処理、圧延率０〜５０％の中間冷間圧延、４００〜５００℃の時効処理、下記（２）式を満たす圧延率での仕上げ冷間圧延を順次施す工程を有する請求項１〜７のいずれかに記載の銅合金板材の製造法。
１０≦ε₂≦（６５−ε₁）／（１００−ε₁）×１００ ……（２）
ここで、ε₁は中間冷間圧延率（％）、ε₂は仕上げ冷間圧延率（％）である。 Cold-rolling with a rolling rate of 85% or more, solution treatment at 700 to less than 800 ° C., intermediate cold rolling with a rolling rate of 0 to 50%, aging treatment at 400 to 500 ° C. The method for producing a copper alloy sheet according to any one of claims 1 to 7, further comprising a step of sequentially performing finish cold rolling at a rolling rate that satisfies the following formula (2).
10 ≦ ε ₂ ≦ (65−ε ₁ ) / (100−ε ₁ ) × 100 (2)
Here, ε ₁ is the intermediate cold rolling rate (%), and ε ₂ is the finish cold rolling rate (%). 仕上げ冷間圧延後に、１５０〜５５０℃の加熱処理を施す工程を有する請求項８に記載の銅合金板材の製造法。   The method for producing a copper alloy sheet according to claim 8, further comprising a step of performing heat treatment at 150 to 550 ° C after finish cold rolling.

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