Cu-Ni-Fe-Si-BASED COPPER ALLOY SHEET, METHOD FOR PRODUCING THE SAME, CONDUCTIVE COMPONENT, AND HEAT-DISSIPATING COMPONENT

Abstract

To improve press punchability while maintaining good bendability in a Corson-type copper alloy sheet having strength and conductivity level ranges with excellent versatility.SOLUTION: A copper alloy sheet has a chemical composition comprising, in mass%, Ni of 1.00 to 4.00%, Fe of 0.10 to 2.00%, Si of 0.20 to 1.20%, S of 0.005 to 0.10%, and one or more elements selected from Mo, Cd, Ti, Mn, Be and Al in a total amount of 0.005 to 1.00%, and optionally containing Ag, B, Co, Cr, Nb, P, Sn, Zn, Zr and rare-earth elements, with the balance being Cu and inevitable impurities. The number density of Ni, Fe and Si-containing particles having a major axis of 0.05 μm or more and 1.0 μm or less is 1.0×104 particles / mm2 or more, and the number density of S-containing particles having a major axis of 3.0 μm or more is 100 particles / mm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a Cu-Ni-Fe-Si based copper alloy sheet material having improved press-punching property and bending property, a method for producing the same, and to an electric-conducting part and a heat-dissipating part using the Cu-Ni-Fe-Si based copper alloy sheet material as a material. [Background technology]

[0002] Cu-Ni-Si copper alloys (known as Corson alloys) and Cu-[Ni,Co]-Si copper alloys in which part or all of the Ni is replaced with Co (hereinafter, these types of alloys will be collectively referred to as "Corson copper alloys") have a relatively good balance of strength and electrical conductivity among copper alloys, and are useful for current-carrying components such as connectors and lead frames, and heat-dissipating components for electronic devices. When copper alloy sheets are processed into current-carrying or heat-dissipating components, they generally undergo press-punching and bending processes. To date, various studies have been conducted on methods to improve the press-punching and bending workability of Corson copper alloys.

[0003] Patent Document 1 discloses a technique for improving the press-punchability of a Corson copper alloy by increasing the number density of precipitates near the surface layer of the sheet compared to the central portion. This document evaluates that a material with little sagging and burrs on the cut surface has good press-punchability (paragraph 0091). No materials containing S are listed. Patent Document 2 discloses a technique for improving the strength and punchability of a Corson copper alloy by adding S and controlling the number density of Mg-S particles. There is no specific teaching regarding the improvement of bending workability. In this document, a material with a small proportion of shear planes on the cut surface is evaluated as having good punchability (paragraph 0050). Patent Document 3 discloses a technique for improving the machinability of Corson copper alloys by adding S. This document is concerned with wrought materials to be subjected to cutting, and specifically describes obtaining round bars through the processes of hot extrusion, water quenching, and cold drawing. There is no mention of the press-punching properties of the resulting plate material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-224922 [Patent Document 2] Japanese Patent Publication No. 2021-134376 [Patent Document 3] Patent No. 4630387 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, with the advances in miniaturization, narrower pitch, and mass production of parts, improving the lifespan of press dies and the dimensional accuracy of punched products has become increasingly important. According to the technology disclosed in Patent Document 2, adding S to Corson copper alloys to create a structure in which Mg-S inclusions are dispersed makes it possible to increase strength and improve press-punching performance (reduction of shear planes). While this improves the lifespan of press dies, there is still room for improvement in the dimensional accuracy of products as measured by the cut edge shape. Furthermore, the addition of S can sometimes reduce bending workability, and this issue has also been desired. Furthermore, while the technology disclosed in Patent Document 2 achieves a very high strength level, there are many applications, such as current-carrying and heat-dissipating components, that do not require such high strength. Excessive strength increases the manufacturing load of parts and can lead to an imbalance between required properties and manufacturing costs.

[0006] The present invention aims to improve press-punching properties of a Corson copper alloy sheet material having a strength level range (tensile strength in the rolling direction of 600 MPa or more) and electrical conductivity range (40% IACS or more) that are excellent for versatility, while maintaining good bending workability, by utilizing a technique of adding S. [Means for solving the problem]

[0007] To improve press-punching performance, it is desirable to examine material properties from the perspectives of (i) extending the life of the die and (ii) improving the dimensional accuracy of the product. Figure 1 shows a schematic diagram of the cross-sectional shape of the cut edge of a metal sheet after press punching. As is well known, the cut edge usually has a sheared surface and a fractured surface. Previous studies have shown that in Corson copper alloys, the smaller the area ratio of the sheared surface to the cut edge (A / (A+B) in Figure 1), the more advantageous it is for extending the die life. On the other hand, gouged defects occur at the fractured surface. In this specification, these defects are called "gouging," and their size (the distance between the boundary between the sheared surface and the fractured surface and the tip of the burr in the direction normal to the cut edge) is expressed as the gouging amount δ. When comparing materials of the same thickness, the smaller the gouging amount δ when press punched under the same conditions, the more advantageous it is for improving the dimensional accuracy of the product.

[0008] According to the investigations of the inventors, when a predetermined amount of S (sulfur) is added to a Corson copper alloy, a microstructure in which S-containing particles are suitably dispersed can be obtained, and the S-containing particles are extremely effective in reducing the area ratio of sheared surfaces, i.e., in extending the life of a die. On the other hand, it was found that adding Fe (iron) is extremely effective in reducing the amount of gouges (δ). Detailed investigations revealed that by adding a specific amount of Fe to a Corson copper alloy and ensuring a sufficient reduction rate during the hot rolling process at temperatures below 800°C and above 600°C, it is possible to obtain a microstructure with a large number of dispersed, relatively large Ni, Fe, and Si-containing particles with major axes of approximately 0.05 to 1.0 μm. Unlike fine precipitates primarily composed of (Ni,Fe)2Si with major axes of less than 50 nm, these Ni, Fe, and Si-containing particles do not contribute much to improving the material's strength (tensile strength). However, they do contribute to reducing the amount of gouges (δ) at the cut edges of press punching, thereby improving the dimensional accuracy of punched products.

[0009] However, simply adding appropriate amounts of S and Fe has proven difficult to consistently achieve both an extension of die life and improved product dimensional accuracy. The reason for this is thought to be that the constituent elements of Ni, Fe, and Si-containing particles, Ni, Fe, and Si, also bond with S, and when these elements combine with S and are consumed to form S-based inclusions, it becomes difficult to ensure the necessary amount of Ni, Fe, and Si-containing particles is produced. Furthermore, when a large amount of Ni forms S-based inclusions together with Fe and Si, the particles tend to coarsen, which also reduces bending workability.

[0010] Therefore, the inventors designed the composition to contain one or more elements selected from Mo, Cd, Ti, Mn, Be, and Al. These elements are thought to form sulfides more easily than Ni, Fe, and Si, and function as a source of S consumption in preference to Ni, Fe, and Si, while also contributing to the formation of S-containing particles that are effective in reducing the area ratio of the sheared surface.

[0011] Furthermore, in order to avoid impairing bending workability, it is important to design the composition and manufacturing process in a way that suppresses the formation of coarse sulfur-containing particles. As a result of our investigations, in terms of composition design, it is effective to avoid adding Mg, which is even more likely to form sulfides than the above-mentioned Mo, Cd, Ti, Mn, Be, and Al. In terms of manufacturing processes, it is extremely effective from the viewpoint of bending workability to ensure a sufficiently large reduction rate in the high-temperature range of 800°C or higher during the hot rolling process. The present invention is based on this technical idea.

[0012] In order to achieve the above object, the present specification discloses the following invention. [1] In mass%, Ni: 1.00 to 4.00%, Fe: 0.10 to 2.00%, Si: 0.20 to 1.20%, S: 0.005 to 0.10%, one or more selected from Mo, Cd, Ti, Mn, Be and Al: total 0.005 to 1.00%, Ag: 0 to 0.30%, B: 0 to 0.20%, Co: 0 to 2.00%, Cr: 0 The chemical composition is Ni: 0.50%, Nb: 0-1.00%, P: 0-0.20%, Sn: 0-1.00%, Zn: 0-1.00%, Zr: 0-0.30%, rare earth elements: 0-1.00% in total, the balance being Cu and unavoidable impurities, and the number density of Ni, Fe, and Si-containing particles with a major axis of 0.05 μm or more and 1.0 μm or less is 1.0 × 10 4 pieces / mm 2 or more, and the number density of S-containing particles with a major axis of 3.0 μm or more is 100 particles / mm 2 The copper alloy sheet material is as follows: [2] The copper alloy sheet material according to [1] above, wherein the total content of Ag, B, Co, Cr, Nb, P, Sn, Zn, Zr, and rare earth elements is 4.00 mass% or less. [3] The number density of S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm is 50 particles / mm 2 More than 2000 pieces / mm 2 The copper alloy sheet material according to the above [1] or [2], which is: [4] The copper alloy sheet material according to any one of the above [1] to [3], which has an electrical conductivity of 40% IACS or more. [5] The copper alloy sheet material according to any one of the above [1] to [4], which has a tensile strength in the rolling direction of 600 MPa or more. [6] The copper alloy sheet material according to any one of the above [1] to [5], wherein the ratio MBR / t of the minimum bending radius MBR at which cracking does not occur to the sheet thickness t in a 90°W bending test at BW in accordance with the Japan Copper and Brass Association technical standard JCBA T307:2007 is 2.5 or less. [7] The copper alloy sheet material according to any one of the above [1] to [6], which has a sheet thickness of 0.02 to 0.80 mm. [8] When manufacturing plate materials using a process including hot rolling, After holding the ingot at a temperature of 900 °C or higher and 1100 °C or lower, hot rolling is performed under the conditions that the rolling ratio in the temperature range of 800 °C or higher is 50% or higher, and the rolling ratio in the temperature range of less than 800 °C and 600 °C or higher is 20% or higher. The method for manufacturing a copper alloy sheet according to any one of [1] to [7] above. [9] A process including subjecting the hot-rolled material obtained by the hot rolling to first intermediate cold rolling, intermediate annealing, final intermediate cold rolling, solution treatment, aging treatment, and finish cold rolling in this order. The method for manufacturing a copper alloy sheet according to [8] above.

[10] A process including subjecting the hot-rolled material obtained by the hot rolling to first intermediate cold rolling, intermediate annealing, final intermediate cold rolling, solution treatment, aging treatment, finish cold rolling, and finish heat treatment in this order. The method for manufacturing a copper alloy sheet according to [8] above.

[11] An electrical component using the copper alloy sheet according to any one of [1] to [7] above as a material.

[12] A heat radiating component using the copper alloy sheet according to any one of [1] to [7] above as a material.

[0013] In this specification, "sheet material" means a sheet-like metal material. A thin sheet-like metal material may also be called "foil", and such "foil" is also included in the "sheet material" referred to here. A long sheet-like metal material wound in a coil shape is also included in the "sheet material". In this specification, the thickness of the sheet-like metal material is called "sheet thickness". Further, "sheet surface" means a surface perpendicular to the sheet thickness direction of the sheet material. The sheet surface may also be called "rolling surface".

[0014] The "long diameter" of the particle is the length of the long axis when the particle is approximated as an ellipse on the image plane.

[0015] The rolling ratio (%) in a certain rolling process is determined by the following formula (1). Rolling ratio (%) = 100 × (h0 - h1) / h0…(¹) h0: The sheet thickness (mm) before being subjected to the first pass of rolling in that rolling process h1: Plate thickness at the end of the final rolling pass in the rolling process (mm) [Effects of the Invention]

[0016] According to the present invention, in a Corson copper alloy sheet material having a strength level range (tensile strength in the rolling direction of 600 MPa or more) and electrical conductivity range (40% IACS or more) excellent in versatility, it is possible to improve press-punching property while maintaining good bending workability. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a diagram showing a cross-sectional shape of a cut edge of a metal plate after press punching. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Chemical composition] Hereinafter, "%" regarding the composition of components means "% by mass" unless otherwise specified.

[0019] This invention focuses on Corson copper alloys containing Fe (iron) in addition to Ni (nickel) and Si (silicon). In this specification, this type of copper alloy is referred to as a Cu (copper)-Ni-Fe-Si-based copper alloy. Ni, Fe, and Si form fine precipitates primarily composed of (Ni,Fe)2Si, contributing to improved strength and electrical conductivity. Furthermore, they form relatively large Ni, Fe, and Si-containing particles with major axes of approximately 0.05 to 1.0 μm, contributing to a reduction in the amount of gouges δ during press punching. The Ni content can be set within a range of 1.00 to 4.00%. The Fe content can be set within a range of 0.10 to 2.00%. The Si content can be set within a range of 0.20 to 1.20%.

[0020] S (sulfur) is an important component element in the present invention. Generally, in copper alloys, S is often treated as an impurity to prevent deterioration of hot workability and material properties. In the manufacturing process of copper alloys, the S content is typically reduced by methods such as degreasing raw materials or flotation separation in the molten metal. However, in the present invention, S-containing particles are dispersed in the material to improve press-punching properties (reduce the shear area ratio). Therefore, a predetermined amount of S is contained in the copper alloy as a source of S-containing particles. After various investigations, it was found that it is effective to control the S content within the range of 0.005 to 0.10%. If the S content is too low, the amount of S-containing particles generated will be insufficient, and the effect of improving press-punching properties will not be fully achieved. The S content is preferably 0.006% or more, and more preferably 0.008% or more. An excessive S content increases the number density of coarse S-containing particles, as described below, deteriorating bending workability. This can also cause deterioration of hot workability and bending workability during manufacturing. The S content is preferably adjusted to a range of 0.09% or less, and more preferably 0.05% or less.

[0021] In the present invention, a Corson copper alloy is designed to incorporate at least one element selected from the group consisting of Mo (molybdenum), Cd (cadmium), Ti (titanium), Mn (manganese), Be (beryllium), and Al (aluminum) in addition to Fe and S. Mo, Cd, Ti, Mn, Be, and Al have lower free energies of sulfide formation than Ni, Fe, and Si, making them more likely to form sulfides. These elements preferentially bond with S over Ni, Fe, and Si, preventing the Ni, Fe, and Si in the copper alloy from being consumed in sulfide formation and ensuring sufficient production of Ni-, Fe-, and Si-containing particles, which contribute to reducing the amount of gouges δ. After extensive investigations, it was found that a total content of at least one element selected from Mo, Cd, Ti, Mn, Be, and Al in the range of 0.005 to 1.00% is effective. In relation to the Fe content, it is more effective to contain one or more of Mo, Cd, Ti, Mn, Be, and Al so that the ratio of [total content (mass%) of Mo, Cd, Ti, Mn, Be, and Al] / [Fe content (mass%)] is in the range of 0.005 or more and 0.70 or less.

[0022] It has been found that when elements with sulfide formation free energies even lower than those of Mo, Cd, Ti, Mn, Be, and Al are added, the sulfides of those elements tend to coarsen, adversely affecting bending workability. One such element is Mg. It is desirable to avoid adding elements with excessively low sulfide formation free energies, such as Mg. The amount of Mg mixed in is preferably less than 0.01 mass%, for example.

[0023] Optional elements may include one or more of Ag (silver), B (boron), Co (cobalt), Cr (chromium), Nb (niobium), P (phosphorus), Sn (tin), Zn (zinc), Zr (zirconium), and rare earth elements. The contents of these optional elements may be set within the following ranges: Ag: 0-0.30%, B: 0-0.20%, Co: 0-2.00%, Cr: 0-0.50%, Nb: 0-1.00%, P: 0-0.20%, Sn: 0-1.00%, Zn: 0-1.00%, Zr: 0-0.30%, and rare earth elements: 0-1.00% in total. The total content of these optional elements is preferably 4.00% by mass or less to achieve a good balance between press-punching properties, bending properties, strength, and electrical conductivity.

[0024] Here, the rare earth elements are Sc (scandium), Y (yttrium), and lanthanoid elements (excluding Pm (promethium)) of Group 3 of the periodic table. Misch metal (a mixture of rare earth elements) may be used as a supply source of the rare earth elements.

[0025] Considering economic efficiency and manufacturability, the contents of the above optional elements are more preferably in the ranges of Ag: 0-0.25%, B: 0-0.16%, Co: 0-1.60%, Cr: 0-0.45%, Nb: 0-0.90%, P: 0-0.16%, Sn: 0-0.95%, Zn: 0-0.95%, Zr: 0-0.25%, and rare earth elements: 0-0.85% in total. In this case, the total of these elements is more preferably 3.00% by mass or less.

[0026] More preferably, the ranges are Ag: 0-0.20%, B: 0-0.12%, Co: 0-1.2%, Cr: 0-0.35%, Nb: 0-0.75%, P: 0-0.12%, Sn: 0-0.85%, Zn: 0-0.85%, Zr: 0-0.20%, and rare earth elements: 0-0.65% in total. In this case, the total of these elements is more preferably 2.00% by mass or less.

[0027] The contents of the above optional elements may be controlled to the following ranges: Ag: 0-0.15%, B: 0-0.08%, Co: 0-0.60%, Cr: 0-0.25%, Nb: 0-0.60%, P: 0-0.08%, Sn: 0-0.75%, Zn: 0-0.75%, Zr: 0-0.15%, and rare earth elements: 0-0.50% in total. In this case, the total content of these elements may be controlled to 1.30% by mass or less.

[0028] The inclusion of elements other than those mentioned above is also permitted to the extent that it does not impair the objective of the present invention (improving press-punching properties while maintaining good bending workability). Specifically, the total content of elements other than Ni, Fe, Si, S, Mo, Cd, Ti, Mn, Be, Al, Ag, B, Co, Cr, Nb, P, Sn, Zn, Zr, rare earth elements, and Cu (hereinafter sometimes referred to as "unspecified elements") is preferably 0.50% or less, and may be controlled to 0.10% or less. The contents of the elements specified in the present invention and unspecified elements can be determined, for example, by quantifying substantially all elements that may be contained in the copper alloy sheet material using the following analytical method.

[0029] (Example of a method for quantifying alloying elements) O (oxygen) and N (nitrogen) are quantified using an oxygen / nitrogen / hydrogen analyzer (e.g., LECO ONH-836), H (hydrogen) is quantified using a hydrogen analyzer (e.g., HORIBA EMGA-921), C (carbon) and S (sulfur) are quantified using a carbon-sulfur analyzer (e.g., LECO CS844), elements from the second to sixth periods (excluding C, N, O, Group 17 elements, Group 18 elements, Tc (technetium), Po (polonium), and Pm (promethium)) are quantified using ICP-MS (e.g., Agilent 7900), and F (fluorine), Cl (chlorine), and Br (bromine) are quantified using a combustion-ion chromatography system (e.g., Thermo Scientific DIONEX ICS-1600).

[0030] The chemical composition of the copper alloy sheet material according to the present invention can also be specified as follows. In mass%, Ni: 1.00 to 4.00%, Fe: 0.10 to 2.00%, Si: 0.20 to 1.20%, S: 0.005 to 0.10%, one or more selected from Mo, Cd, Ti, Mn, Be, and Al: 0.005 to 1.00% in total, Ag: 0 to 0.30%, B: 0 to 0.20%, Co: 0 to 2.00%, Cr: 0 to 0.50%, Nb: 0 to 1.00 %, P: 0-0.20%, Sn: 0-1.00%, Zn: 0-1.00%, Zr: 0-0.30%, Rare earth elements: 0-1.00% in total, Ni, Fe, Si, S, Mo, Cd, Ti, Mn, Be, Al, Ag, B, Co, Cr, Nb, P, Sn, Zn, Zr, Elements other than rare earth elements and Cu (non-specified elements): 0.50% in total or less, balance Cu In this case, the total content of the above non-specified elements is more preferably 0.10% or less, and among the non-specified elements, the content of Mg is even more preferably less than 0.01%.

[0031] [Ni, Fe, Si containing particles] In this specification, "Ni, Fe, Si-containing particles" refer to second-phase particles having a major axis of 0.05 μm or more present in a copper alloy, in which the presence of predetermined amounts of Ni, Fe, and Si is observed by EDX (energy dispersive X-ray fluorescence analysis). Ni, Fe, Si-containing particles having a major axis of 0.05 μm or more and 1.0 μm or less are present at a number density of 1.0×10 4 pieces / mm 2 By achieving the above-described dispersed structure, it is possible to prevent the amount of gouges δ from increasing at the cut edge of the press punch. 4 pieces / mm 2 More preferably, it is 10.0×10 4 pieces / mm 2 The upper limit of the number density of Ni, Fe, and Si-containing particles having a major axis of 0.05 μm or more and 1.0 μm or less is not particularly limited, but in the chemical composition specified in the present invention, it is usually 100.0×10 4 pieces / mm 2 The result is 80.0×10 4 pieces / mm 2 It may be the following:

[0032] (Method for measuring the number density of particles containing Ni, Fe, and Si) The surface of the copper alloy sheet is polished to obtain a sample surface for EDX measurement. The sample surface is observed using an FE-SEM (field emission scanning electron microscope) equipped with an EDX device, and a measurement area, for example, 30 μm x 40 μm in size, is randomly determined. A secondary electron image is obtained for this measurement area under conditions of an acceleration voltage of 15 kV and a working distance of 10 mm. EDX point analysis is performed on this secondary electron image. Particles in which concentrations of Ni, Fe, and Si are observed to be 0.5% by mass or higher are determined to be Ni, Fe, and Si-containing particles. By comparing the secondary electron image with the EDX analysis data, particles located at EDX measurement spots in which concentrations of Ni, Fe, and Si are observed to be 0.5% by mass or higher are determined to be "target particles" with a major axis between 0.05 μm and 1.0 μm, and the number of target particles present in the measurement area is counted. For particles partially cut off by the boundary of the measurement area, the boundary portion is considered to be part of the particle's outline, and the major axis is measured for the portion of the particle within the measurement area. The total number of particles counted is calculated by dividing the total number of particles by the area of ​​the measurement region (mm 2 ) to obtain the number density (pieces / mm 2 ) is calculated. This number density calculation operation is performed for three or more non-overlapping measurement areas, and the arithmetic mean of the number density values ​​of the corresponding particles obtained in each measurement area is calculated, and this is used as the number density of Ni-, Fe-, and Si-containing particles with a major axis of 0.05 μm to 1.0 μm in the plate material. Note that the measurement of the major axis of the particles and the counting of the number of particles can be performed using image processing software (e.g., ImageJ).

[0033] [S-containing particles] In this specification, "S-containing particles" refer to second phase particles present in a copper alloy, in which the presence of a predetermined amount of S is observed by EDX (energy dispersive X-ray fluorescence analysis). Such particles include particles of S alone and compound particles containing S. In the present invention, one or more of Mo, Cd, Ti, Mn, Be, and Al, which easily bond with S, are intentionally contained. Compound particles are formed that are mainly composed of sulfides with these metals.

[0034] S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm have a density of 50 particles / mm 2 More than 2000 pieces / mm 2 Less than 50 / mm 2 More than 1300 pieces / mm 2 Achieving a structure in which the particles are dispersed at or below a specific diameter is even more effective in reducing the proportion of sheared surfaces in the cut edges of press punching to 30% or less, thereby extending the life of the die. S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm are thought to be the starting points for fracture during press working, which is thought to contribute to reducing the proportion of sheared surfaces. In Corson copper alloys, the number density of S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm can be kept within a specified range by adjusting the S content in the alloy to 0.005% by mass or more and 0.10% by mass or less.

[0035] On the other hand, it was found that coarse S-containing particles with a major axis of 3.0 μm or more cause deterioration in bending workability. As a result of the investigation, it was found that in order to improve press formability and maintain sufficient bending workability, the number density of S-containing particles with a major axis of 3.0 μm or more should be 100 particles / mm 2 It is extremely effective to keep it below 80 pieces / mm 2 From the viewpoint of bending workability, it is more preferable that the number of wires is 60 wires / mm or less. 2 It is more preferable that the density is 40 or less per mm 2In order to sufficiently suppress the generation of coarse S-containing particles having a major axis of 3.0 μm or more in a Corson copper alloy in which the S content in the alloy is adjusted to 0.005% by mass or more, it is extremely effective to adopt manufacturing conditions that ensure a sufficient total rolling reduction in the high temperature region in hot rolling, as will be described later. Note that it is particularly preferable to set the number density of S-containing particles having a major axis of 3.0 μm or more to 0 particles / mm 2 It is difficult to achieve this in manufacturing, and the normal density is 1 piece / mm 2 That's all.

[0036] (Method for measuring the number density of S-containing particles) The surface of the copper alloy sheet is polished to obtain a sample surface for EDX measurement. The sample surface is observed using an FE-SEM (field emission scanning electron microscope) equipped with an EDX device, and a measurement area, for example, 300 μm x 400 μm in size, is randomly determined. A secondary electron image of this measurement area is obtained under conditions of an acceleration voltage of 15 kV and a working distance of 10 mm. EDX point analysis is performed on this secondary electron image. Particles with an observed S concentration of 0.5 mass% or more are determined to be S-containing particles. By comparing the secondary electron image with the EDX analysis data, particles located at EDX measurement spots where an S concentration of 0.5 mass% or more is observed are determined to be S-containing particles with a major axis of 1.5 μm or more but less than 3.0 μm as "relevant particle A," and particles with a major axis of 3.0 μm or more as "relevant particle B." The number of relevant particles A and relevant particles B present in the measurement area is counted. For particles that are partially cut off by the boundary of the measurement area, the boundary portion is considered to be part of the particle's outline, and the major axis is measured for the particle portion that is within the measurement area. The total number of counted particles A and B is calculated based on the area of ​​the measurement area (mm 2 ) to obtain the number density (particles / mm 2) is calculated. This number density calculation operation is performed for three or more non-overlapping measurement areas, and the arithmetic mean values ​​of the number density values ​​of corresponding particles A and corresponding particles B obtained in each measurement area are calculated. These are used as the number density of S-containing particles with a major axis of 1.5 μm or more but less than 3.0 μm and the number density of S-containing particles with a major axis of 3.0 μm or more in the plate material, respectively. Note that the measurement of the major axis of the particles and the counting of the number of particles can be performed using image processing software (e.g., ImageJ).

[0037] [Tensile strength / conductivity] The strength level required for copper alloy sheets used in current-carrying parts such as connectors and heat-dissipating parts for electronic devices varies depending on the application, and excessively high strength increases the manufacturing load of the parts and leads to increased manufacturing costs. In the present invention, it is possible to cover a highly versatile strength level range, for example, a rolling direction tensile strength of 600 MPa or more and 950 MPa or less. The rolling direction tensile strength may be adjusted to a range of 600 MPa or more and less than 900 MPa. Regarding electrical conductivity, a conductivity of 40% IACS or more can be obtained. The conductivity of the copper alloy sheet according to the present invention is usually in the range of 70% IACS or less.

[0038] [Bending workability] Bending is often involved in processing into current-carrying components, etc. Considering the uses of Corson copper alloy sheet materials, in order to obtain high reliability when processing into current-carrying components and heat-dissipating components, it is desirable for the sheet to have bending workability such that the ratio MBR / t of the minimum bending radius MBR at which cracking does not occur to the sheet thickness t is 2.5 or less in a 90°W bending test at BW in accordance with the Japan Copper and Brass Association technical standard JCBA T307:2007. MBR / t at BW is more preferably 2.0 or less, and even more preferably 1.5 or less. BW (Bad Way) means that the bending axis is parallel to the rolling direction.

[0039] JCBA T307:2007 states that "This standard applies to the evaluation of the bending workability of copper and copper alloy thin sheet strips with a thickness of 0.1 mm or more and 0.8 mm or less." The inventors' studies have confirmed that it is possible to evaluate the bending workability of Corson copper alloy sheets with a thickness of less than 0.1 mm by the W-bend test method described in the standard. Therefore, in the present invention, the BW W-bend test method described in JCBA T307:2007 is extended to cases with a thickness of less than 0.1 mm (for example, 0.02 mm or more and less than 0.1 mm) and is applied as is.

[0040] [Press punching ability] The copper alloy sheet of the present invention is a Corson copper alloy sheet exhibiting excellent strength and electrical conductivity levels for versatility, while maintaining good bending workability and achieving excellent press-punchability. Regarding press-punchability, when a square test piece is punched from the copper alloy sheet using a press die with a clearance set to 10% of the sheet thickness, the shear area ratio, as determined by the method described in the Examples below, is preferably 30% or less. This shear area ratio is typically 18% or more. Furthermore, when a test piece is punched, the gouge ratio, as determined by the method described in the Examples below, is preferably 10% or less. This gouge ratio is typically 3% or more. In Figure 1 , the amount of gouge δ tends to increase as the sheet thickness t of the copper alloy sheet increases. The gouge ratio indicates the relative magnitude of the amount of gouge δ relative to the sheet thickness t, which has such a relationship.

[0041] [Manufacturing method] The copper alloy sheet material described above can be manufactured, for example, by the following manufacturing process. Casting → Hot rolling → First intermediate cold rolling → Intermediate annealing → Final intermediate cold rolling → Solution treatment → Aging treatment → Finish cold rolling → Finish heat treatment Although not described in the above steps, facing is carried out as needed after the hot working, and pickling, polishing, or further degreasing is carried out as needed after each heat treatment. Each of the above steps will be explained below.

[0042] [casting] A cast slab having the chemical composition specified in the present invention is produced. For the addition of S, it is preferable to use, for example, a Cu-S master alloy prepared in advance. As the casting method, a general method such as continuous casting, semi-continuous casting, or ingot casting can be applied.

[0043] [Hot rolling] After heating the slab, it is subjected to hot rolling. The heating temperature of the slab is preferably 900°C or higher and 1100°C or lower. The holding time within the above temperature range is preferably 0.5 hours or higher, and more preferably 0.5 hours or higher and 7 hours or lower.

[0044] The heated slab is removed from the furnace and hot rolling begins. Hot rolling is performed according to a pass schedule in which the reduction ratio is 50% or more in the temperature range above 800°C, and 20% or more in the temperature range below 800°C and above 600°C. The rolling temperature in each rolling pass can be monitored by the surface temperature of the material immediately after it leaves the work rolls of the hot rolling mill. "50% or more reduction ratio in the temperature range above 800°C" means that the reduction ratio determined in equation (1) above is 50% or more, where h0 is the plate thickness (slab thickness) before the start of the first rolling pass in hot rolling, and h1 is the plate thickness at the end of the last rolling pass where the rolling temperature is above 800°C. "A rolling ratio of 20% or more in a temperature range of 600°C or more but less than 800°C" means that in the above formula (1), the rolling ratio determined by substituting the plate thickness before the start of the first rolling pass where the rolling temperature is less than 800°C for h0 and the plate thickness at the end of the last rolling pass where the rolling temperature is 600°C or more for h1 is 20% or more.

[0045] In the temperature range of 800°C or higher, dynamic recrystallization is used to break up the coarse S-containing second phases present in the cast structure, resulting in a homogenized structure. If the rolling reduction rate in this temperature range is less than 50%, the final number density of S-containing particles with a major axis of 3.0 μm or more will be 100 particles / mm 2 It becomes difficult to stably obtain a structure state reduced below this temperature. The rolling ratio in the temperature range of 800°C or higher is preferably set within the range of 50% or more and 85% or less.

[0046] On the other hand, the generation of particles containing Ni, Fe, and Si is promoted during the rolling process in the temperature range of 600°C or higher and less than 800°C. As a result of the investigation, it was found that by ensuring a rolling reduction rate of 20% or more in the temperature range of 600°C or higher and less than 800°C to generate sufficient particles containing Ni, Fe, and Si, and then subjecting the material to the processes including the solution treatment and aging treatment described below, the number density of particles containing Ni, Fe, and Si with a major axis of 0.05 μm or more and 1.0 μm or less can be finally reduced to 1.0 × 10 4 pieces / mm 2 If the rolling reduction ratio is insufficient in the temperature range of 600°C or higher but lower than 800°C, fine precipitates mainly composed of (Ni,Fe)2Si that contribute to improving strength can be precipitated by aging treatment, but the number of Ni, Fe, and Si-containing particles with a major axis of 0.05 μm or higher and 1.0 μm or lower is likely to be insufficient, and the effect of reducing the amount of gouges δ will not be fully exerted. It is preferable to set the rolling reduction ratio in the temperature range of 600°C or higher but lower than 800°C within the range of 20% or higher and 50% or lower.

[0047] The total rolling reduction in hot rolling is preferably set in the range of 70% to 95%, for example. Here, the "total rolling reduction in hot rolling" refers to the rolling reduction determined by substituting the plate thickness (slab thickness) before the start of the first rolling pass in hot rolling for h0 and the plate thickness at the end of the final rolling pass in hot rolling for h1 in the above formula (1).

[0048] [First intermediate cold rolling, intermediate annealing, final intermediate cold rolling] Prior to the solution treatment, it is preferable to perform multiple cold rolling steps with intermediate annealing in between. In this specification, the first cold rolling step performed after the hot rolling step is referred to as the "first intermediate cold rolling step," and the last cold rolling step performed before the solution treatment step is referred to as the "final intermediate cold rolling step." The first intermediate cold rolling is preferably performed at a total rolling reduction of 60% or more. The final intermediate cold rolling is preferably performed at a total rolling reduction of 70% or more to introduce strain that promotes recrystallization in the subsequent solution treatment. The upper limit of the total rolling reduction for each of these cold rolling processes can be set appropriately depending on the capacity of the rolling mill. It is usually sufficient to set it in the range of 99% or less. The intermediate annealing performed between the first intermediate cold rolling and the final intermediate cold rolling can be performed under conditions of holding the temperature at 500°C or higher and 700°C or lower, more preferably 500°C or higher and 600°C or lower, for 0.1 hours or higher and 20 hours or lower. If necessary, one or more steps of intermediate cold rolling and intermediate annealing may be inserted between the intermediate annealing and the final intermediate cold rolling. In this case, the inserted intermediate annealing may be performed under the same conditions as the intermediate treatment, and the inserted intermediate cold rolling may be performed under the same conditions as the first intermediate cold rolling.

[0049] [Solution treatment, aging treatment] Next, solution treatment is performed at a temperature of 780°C to 1000°C for 10 to 600 seconds, followed by aging treatment at a temperature of 400°C to 570°C, more preferably 430°C to 550°C, for 1 to 24 hours.

[0050] [Finishing cold rolling, finishing heat treatment] After aging, the steel sheet is subjected to finish cold rolling under conditions of a total rolling reduction of 10% to 80%, more preferably 10% to 40%. A finish heat treatment is then performed to reduce residual stress, improve bending workability, and improve stress relaxation resistance by reducing voids and dislocations on slip planes. The conditions for the finish heat treatment should be a holding temperature of 150°C to 500°C and a holding time of 5 seconds to 18,000 seconds, within which heating conditions that do not cause recrystallization can be adopted. The final sheet thickness can be, for example, in the range of 0.02 to 0.80 mm.

[0051] [Electrical and heat-dissipating parts] The Cu-Ni-Fe-Si copper alloy sheet material obtained in this manner has excellent press-punching properties and good bending workability, and can be adjusted to versatile strength and conductivity levels. This sheet material can be processed into current-carrying parts such as connectors with high dimensional accuracy and heat-dissipating parts for electronic devices using a processing process that reduces manufacturing costs by improving mold life and avoiding excessive manufacturing loads. [Example]

[0052] Copper alloys having the chemical compositions shown in Tables 1 to 4 were melted and cast into slabs using a vertical semi-continuous casting machine. The gas phase space in contact with the molten metal during casting was air. A Cu-19.7 mass% S alloy was used to add S. The analytical samples taken from the slabs were analyzed for the elements listed in Tables 1 to 4 using the method described in the above section "Examples of methods for quantifying alloying elements." The Mg content was less than 0.01% by mass in all cases, except where explicitly stated.

[0053] The resulting slabs were held at the temperatures and times shown in Tables 1 to 4, then removed from the furnace and hot-rolled by controlling the rolling reduction ratios in each temperature range as shown in Tables 1 to 4. After hot-rolling, the surface oxide layer was removed (face-ground) by mechanical polishing. Except for some samples (Nos. 49, 52, and 53), the slabs were then subjected to first intermediate cold rolling, intermediate annealing, final intermediate cold rolling, solution treatment, aging treatment, finish cold rolling, and finish heat treatment in the order shown in Tables 1 to 4. No. 49 omitted intermediate annealing, final intermediate cold rolling, and finish heat treatment. No. 52 omitted final intermediate cold rolling. No. 53 omitted intermediate annealing and final intermediate cold rolling. The holding time for intermediate annealing in No. 50 was 45 seconds. The rolling ratios (%) in each rolling step and the total rolling ratio (%) shown in the table are rounded to the nearest whole number. In each example, the test material was a plate obtained by finish heat treatment (No. 49 was finish cold rolled), and the test material was subjected to the following investigation. The test material thickness was 0.2 mm in each example.

[0054] (Measurement of the number density of particles containing Ni, Fe, Si and S) According to the "Method for measuring the number density of Ni-, Fe-, and Si-containing particles" and "Method for measuring the number density of S-containing particles" mentioned above, the specimen surface parallel to the plate surface of the test material was observed using an FE-SEM (JEOL JSM-7200F) equipped with an EDX device, and each particle was identified by EDX analysis and secondary electron images were taken. The specimen surface was prepared by mechanical polishing using #1000 abrasive paper, followed by electrolytic polishing. Electrolytic polishing was performed at 15 V for 20 seconds.

[0055] The number density of particles containing Ni, Fe, and Si was measured in three non-overlapping measurement areas (total area 0.0036 mm) under the following conditions: the size of one measurement area was 30 μm × 40 μm, the magnification was 3000 times, the acceleration voltage was 15 kV, the probe current number was 13, the scale of the objective aperture was 2, and the working distance was 10 mm. 2 ) were measured. The number density of S-containing particles was measured in three non-overlapping measurement areas (total area 0.36 mm) under the following conditions: the size of one measurement area was 300 μm × 400 μm, the magnification was 300 times, the acceleration voltage was 15 kV, the probe current number was 13, the scale of the objective aperture was 2, and the working distance was 10 mm. 2 ) were measured. Measurement of the major axis of the particles and counting of the number of particles whose major axis was within a predetermined range were carried out using image analysis software ImageJ (National Institutes of Health (NIH), Version 1.52a) according to the following method.

[0056] First, in the secondary electron image, particles determined by EDX point analysis not to be Ni, Fe, or Si-containing particles in the Ni, Fe, or Si-containing particle measurement, or particles determined not to be S-containing particles in the S-containing particle measurement, are blacked out. The software analysis conditions are then set by selecting Analyze and Set Scale, then measuring the number of pixels along the scale bar length of the captured FE-SEM image on the "Set Scale" screen, and entering this in "Distance in pixels." Next, enter the length of the scale bar (μm) in "Known distance," set the pixel aspect ratio to 1.0, and set the unit of length to μm so that the size of the precipitates can be recognized in the software. Then, in the "Resize Image Canvas" screen, set the width to 1280 pixels, the height to 800 pixels, and the position to top-center, and display the FE-SEM image excluding the scale bar. After setting this scale and deleting the scale bar display, the "Threshold" screen was displayed by selecting Image, Adjust, and Threshold in that order, and the brightness was inverted so that the lowest brightness pixel of all pixels had a brightness of 255 and the highest brightness pixel had a brightness of 0. The threshold was then set to a value that would bring the proportion of pixels below that value to all pixels closest to 2%, and the areas where precipitate particles existed were binarized and identified. After that, on the "Analyze Particles" screen of the same software, the area of ​​one independent precipitate region was set to 0.1 μm. 2Set Size to "0.10-Infinity" as a condition to exclude particles with a diameter less than this. Furthermore, set Circularity to 0.00-1.00 and check the Fit Ellipse box on the "Set Measurements" screen, and perform particle analysis. When measuring Ni, Fe, and Si-containing particles, count the number of Ni, Fe, and Si-containing particles with a major diameter (displayed as the "Major" item) of 0.05 μm or more and 1.0 μm or less in the field of view. When measuring S-containing particles, count the number of S-containing particles (relevant particle A) with a major diameter (displayed as the "Major" item) of 1.5 μm or more and less than 3.0 μm in the field of view, and the number of S-containing particles (relevant particle B) with a major diameter (displayed as the "Major" item) of 3.0 μm or more in the field of view.

[0057] (conductivity) The electrical conductivity of each test material was measured using the double bridge, average cross-sectional area method in accordance with JIS H0505. Considering the electrical conductivity required for current-carrying parts such as small connectors, materials with a conductivity of 40% IACS or higher were judged to pass.

[0058] (tensile strength) Tensile test pieces (JIS No. 5) were taken from each test material in the rolling direction, and tensile tests were conducted in accordance with JIS Z2241 with n=3 tests to measure tensile strength. The average value of n=3 was used as the performance value for the test material. From the perspective of ensuring high reliability in current-carrying parts such as connectors, those with a tensile strength of 600 MPa or more in the rolling direction were judged to pass.

[0059] (bending workability) In accordance with the Japan Copper and Brass Association technical standard JCBA T307:2007, a 90°W bending test was performed on the blank wall to determine the ratio (MBR / t) of the minimum bending radius (MBR) at which cracks did not occur to the sheet thickness (t). The test specimen size was 30 mm in the direction perpendicular to the rolling direction on the sheet surface and 2 mm in the rolling direction (width of the test specimen). The presence or absence of cracks on the bent surface was determined according to JCBA T307:2007. For samples judged to have "large wrinkles" in the appearance observation of the bent surface, a specimen was cut perpendicular to the bending axis at the deepest wrinkle, and the polished cross section was observed under an optical microscope to check for cracks extending into the sheet thickness. If no cracks were found, the specimen was judged to have "no cracks observed." Considering the intended use of the material of the present invention, a specimen with an MBR / t of 2.5 or less in this test was judged to pass.

[0060] (Press punching ability) A test was conducted in which a 0.2 mm thick test material was punched out into a 5 mm x 5 mm square test piece using a press die. The clearance was 10% of the plate thickness. The square test piece was punched so that two of the four cut edges (end faces) formed on it were perpendicular to the rolling direction.

[0061] The evaluation method for press-punchability is described with reference to Figure 1. The size of the burrs is exaggerated in Figure 1. The surface height of the cut surface perpendicular to the rolling direction of the test specimen, as viewed normal to the cut surface (in this case, parallel to the rolling direction), was measured along a line along the entire length in the thickness direction (the punch axial direction) using a laser microscope, and a surface roughness profile was created. From this profile, the length of the sheared surface, indicated by symbol A in Figure 1, was determined, and the ratio of the sheared surface to the sheared surface and fractured surface was calculated. For ease of measurement, the length including the burr portion, indicated by symbol B in Figure 1, was considered to be the length of the fractured surface, and the "sheared surface ratio" was calculated using the following equation (2). In this press-punchability test, the height of the burrs is typically less than 1 μm, so including the burrs in the length of the fractured surface does not interfere with the evaluation of press-punchability. Shear surface ratio (%) = 100 (%) × A / (A + B) … (2) Furthermore, the distance between the boundary between the shear surface and the fracture surface and the tip of the burr in the direction normal to the cut was calculated from the profile, and this was defined as the amount of gouging δ (mm). In relation to the sheet thickness t (mm), the "gouging ratio" was calculated using the following formula (3): Egler rate (%) = 100 (%) × δ / t … (3)

[0062] This measurement was performed at 10 locations on the cut edge (edge) perpendicular to the rolling direction of the test piece. The shear surface ratio was calculated using equation (2) and the gouge ratio was calculated using equation (3) for each location. The arithmetic mean values ​​were used as the shear surface ratio and gouge ratio for the test material. In this test, if the shear surface ratio at a 10% clearance is 30% or less, it can be determined that a significant improvement in die life has been achieved compared to conventional Corson copper alloy sheet materials. Furthermore, if the gouge ratio at a 10% clearance is 10% or less, it can be determined that a significant improvement in the dimensional accuracy of the cut edge has been achieved compared to conventional Corson copper alloy sheet materials. Therefore, in the above test with a 10% clearance, a shear surface ratio of 30% or less and a gouge ratio of 10% or less were determined to pass. The results are shown in Tables 1 to 4.

[0063] [Table 1]

[0064] [Table 2]

[0065] [Table 3]

[0066] [Table 4]

[0067] In the test materials of each example, which contained predetermined amounts of Fe, S, and one or more elements selected from predetermined amounts of Mo, Cd, Ti, Mn, Be, and Al, and in which the number densities of Ni, Fe, and Si-containing particles with major axes of 0.05 μm to 1.0 μm and S-containing particles with major axes of 3.0 μm or more were controlled within the appropriate ranges described above, all of them maintained good bending workability while achieving significant improvements in press-punching properties, and there were no problems with strength levels or electrical conductivity.

[0068] In contrast, in the comparative example No. 41, the number density of S-containing particles having a major axis of 3.0 μm or more could not be reduced sufficiently due to the high S content, and bending workability was poor. In No. 42, the number density of S-containing particles with major axes of 1.5 μm or more and less than 3.0 μm was insufficient due to the low S content, and the reduction in shear surface ratio was insufficient. In addition, the electrical conductivity was low due to the increased amount of solute elements. No. 43 had low conductivity because the Fe content was too high. In No. 44, the Fe content was insufficient, resulting in an insufficient amount of particles containing Ni, Fe, and Si with major axes of 0.05 μm to 1.0 μm, and the rate of eruptions was high. In No. 45, the reduction ratio during hot rolling at temperatures below 800°C and above 600°C was insufficient, resulting in an insufficient amount of particles containing Ni, Fe, and Si with major axes of 0.05 μm to 1.0 μm, and a high rate of hollowing. In No. 46, the reduction ratio at 800°C or higher during hot rolling was insufficient, resulting in an increase in S-containing particles with major axes of 3.0 μm or more, and poor bending workability. In No. 47, the Ni and Si contents were low, which resulted in insufficient formation of fine precipitates, resulting in poor strength and electrical conductivity. Furthermore, the amount of Ni-, Fe-, and Si-containing particles with major axes of 0.05 μm to 1.0 μm was insufficient, resulting in a high rate of eruptions. No. 48 did not contain one or more elements selected from Mo, Cd, Ti, Mn, Be, and Al, and therefore had many S-containing particles with major diameters of 3.0 μm or more, resulting in poor bending workability.

[0069] In Nos. 49 and 51, no Fe was added, so no particles containing Ni, Fe, or Si were generated, resulting in a high rate of gouges. In addition, because the S content was low, the amount of S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm was insufficient, resulting in a high shear surface ratio. No. 50 contains added Fe, but the reduction ratio during hot rolling at temperatures below 800°C and above 600°C was insufficient, resulting in an insufficient amount of Ni, Fe, and Si-containing particles with major axes of 0.05 μm to 1.0 μm, resulting in a high gouge rate and poor electrical conductivity. Furthermore, the low S content resulted in an insufficient amount of S-containing particles with major axes of 1.5 μm to 3.0 μm, resulting in a high shear surface ratio. In No. 52, the Ni and Fe contents were low, which resulted in an insufficient amount of Ni, Fe, and Si-containing particles, and a high rate of gouges. In addition, the S content was low, which resulted in an insufficient amount of S-containing particles with major axes of 1.5 μm to 3.0 μm, and a high rate of sheared surfaces. In No. 53, since no Fe was added, particles containing Ni, Fe, and Si were not generated, resulting in a high rate of eruptions. In addition, since No. 53 contains S and Mg, which has a low free energy of sulfide formation, the number of coarse S-containing particles increased, resulting in poor bending workability.

Claims

1. In mass%, Ni: 1.00 to 4.00%, Fe: 0.10 to 2.00%, Si: 0.20 to 1.20%, S: 0.005 to 0.10%, one or more selected from Mo, Cd, Ti, Mn, Be, and Al: 0.005 to 1.00% in total, Ag: 0 to 0.30%, B: 0 to 0.20%, Co: 0 to 2.00%, Cr: 0 to 0 0.50%, Nb: 0-1.00%, P: 0-0.20%, Sn: 0-1.00%, Zn: 0-1.00%, Zr: 0-0.30%, rare earth elements: 0-1.00% in total, balance Cu and unavoidable impurities, and the number density of Ni-, Fe-, and Si-containing particles having a major axis of 0.05 μm or more and 1.0 μm or less is 1.0×10 ４ pieces / mm ２ or more, and the number density of S-containing particles having a major axis of 3.0 μm or more is 100 particles / mm ２ The copper alloy sheet material is as follows:

2. 2. The copper alloy sheet according to claim 1, wherein the total content of Ag, B, Co, Cr, Nb, P, Sn, Zn, Zr, and rare earth elements is 4.00 mass% or less.

3. The number density of S-containing particles with a major axis of 1.5 μm or more and less than 3.0 μm is 50 particles / mm ２ More than 2000 pieces / mm ２ The copper alloy sheet material according to claim 1, wherein:

4. 2. The copper alloy sheet material according to claim 1, having an electrical conductivity of 40% IACS or more.

5. 2. The copper alloy sheet material according to claim 1, wherein the tensile strength in the rolling direction is 600 MPa or more.

6. 2. The copper alloy sheet material according to claim 1, wherein a ratio MBR / t of a minimum bending radius MBR at which cracking does not occur to a sheet thickness t in a 90° W bending test at B.W. in accordance with Japan Copper and Brass Association Technical Standard JCBA T307:2007 is 2.5 or less.

7. The copper alloy sheet material according to claim 1, wherein the sheet thickness is 0.02 to 0.80 mm.

8. When manufacturing plate materials using a process including hot rolling, 2. The method for producing a copper alloy sheet according to claim 1, wherein the slab is heated and held at 900°C or higher and 1100°C or lower, and then hot rolling is performed under conditions where the rolling reduction rate in a temperature range of 800°C or higher is 50% or higher, and the rolling reduction rate in a temperature range of lower than 800°C and 600°C or higher is 20% or higher.

9. 9. The method for producing a copper alloy sheet according to claim 8, comprising a process of subjecting the hot-rolled material obtained by the hot rolling to first intermediate cold rolling, intermediate annealing, final intermediate cold rolling, solution treatment, aging treatment, and finish cold rolling in this order.

10. 9. The method for producing a copper alloy sheet according to claim 8, comprising a process of subjecting the hot-rolled material obtained by the hot rolling to first intermediate cold rolling, intermediate annealing, final intermediate cold rolling, solution treatment, aging treatment, finish cold rolling, and finish heat treatment in this order.

11. A current-carrying part using the copper alloy sheet material according to any one of claims 1 to 7 as a material.

12. A heat dissipation part using the copper alloy sheet material according to any one of claims 1 to 7 as a material.

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