Copper alloy sheet material and drawn article

Abstract

The invention relates to a copper alloy sheet and a drawn product. Provided is a copper alloy sheet material which has excellent bending workability, is capable of obtaining excellent drawing workability, and in particular, is capable of reducing lugs formed at the edge of a drawn product. The copper alloy sheet material has an alloy composition containing Cr in the range of 0.10-1.00 mass%, with the remainder comprising Cu and unavoidable impurities, and has a crystal orientation curve {011} lt; 211gt, 211gt; the Brass orientation is as follows: {123} lt; 634gt, 634gt; s orientation and {112} lt; 111gt, 111gt; the proportion of the total area of crystal grains oriented by the Copper orientation in the area of the measurement region is in the range from 25% to 38% (inclusive), and is along {001} lt; 100 gt; the ratio of the area of crystal grains in which the Cube orientation is oriented to the area of the measurement region is 12% or more.

Description

Technical Field

[0001] This invention relates to copper alloy plates and deep-drawn products. Background Technology

[0002] Copper alloy sheets can be used in connectors, lead frames, relays, switches, sockets, shielding covers, shielding shells, camera modules, heat dissipation components for LCD and OLED displays, batteries, etc., for electronic devices or automobiles. They are often subjected to stamping processes such as bending, deep drawing, punching, and stretching.

[0003] As a copper alloy for stamping, for example, Patent Document 1 discloses a copper alloy containing, by mass percent, Cr: 0.10~0.50%, Ti: 0.010~0.30%, and Si: 0.01~0.10%, and in such a manner that the mass ratio of Cr to Ti is 1.0 ≤ (Cr / Ti) ≤ 30 and the mass ratio of Cr to Si is 3.0 ≤ (Cr / Si) ≤ 30, with the balance including copper and unavoidable impurities. This copper alloy has a Brass orientation {011} when its crystal orientation is determined using the FESEM-EBSP method. <211> S-orientation {123} <634> and Copper orientation {112} <111> The total average area fraction of the texture is 40% to 70%. Patent Document 1 states that for the crystal orientation of Cu-Cr-Ti-Si alloys, the Brass orientation {011} is considered... <211> S-orientation {123} <634> and Copper orientation {112} <111> When the total average area ratio is controlled at 40%~70%, a copper alloy with excellent strength and conductivity, as well as excellent bending workability, can be obtained.

[0004] Additionally, Patent Document 2 discloses a copper alloy plate containing 0.1-0.6% by mass of Cr, 0.01-0.30% by mass of Zr, and one or two of Ti, with the balance including copper and unavoidable impurities. In crystal orientation analysis during EBSD determination, the Cube orientation is {001}. <100> The area ratio is less than 10%, Brass orientation {110} <112> The area ratio is below 40%, Copper orientation {112} <111> The area fraction is over 20%, and there are 100,000 second-phase particles with a size greater than 0.1 μm per mm. 2Below. In Patent Document 2, it is believed that by controlling the Cube orientation {001} in the Cu-Cr-(Zr,Ti) alloy... <100> Brass orientation {110} <112> and Copper orientation {112} <111> By adjusting the area ratio and the density of the second phase particles, a copper alloy plate can be obtained that maintains conductivity and strength while exhibiting excellent bending workability, stress relief rate, and Young's modulus.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2013-173988 Patent Document 2: Japanese Patent Application Publication No. 2019-157256 Summary of the Invention

[0006] The problem that the invention aims to solve With the increasing performance, high current, and miniaturization of electronic and automotive equipment in recent years, there is a growing demand for high mechanical properties and electrical conductivity (or thermal conductivity) in the stamped parts that constitute these components. This is especially true for deep-drawn parts used in electronic and automotive equipment, such as connectors, lead frames, relays, switches, sockets, shielding covers, shielding shells, camera module housings, vibration device housings, heat dissipation components for LCDs and OLEDs, batteries, probe pins, and gas shielding valves. These require copper alloy sheets made from materials that simultaneously achieve higher mechanical properties and electrical conductivity (or thermal conductivity) than previously used copper alloys such as brass and zinc-copper alloys. Cu-Cr alloys are examples of materials with high strength and electrical conductivity (thermal conductivity), but their insufficient elongation makes them unsuitable for complex processing. Therefore, copper alloy sheets made from Cu-Cr alloys are needed, possessing excellent bending and deep-drawing capabilities.

[0007] Here, "deep drawing" refers to a metal sheet forming method, typically involving pressing a punch into a thin metal sheet to form bottomed containers of various shapes, such as cylinders, prismatic tubes, and cones. Furthermore, "deep-drawn products" refer to products formed through deep drawing, characterized by the absence of seams. It should be noted that "deep-drawn products" also includes products formed by combining deep drawing with other processing methods, such as bending, compression, and torsion.

[0008] Increasing the depth of the drawing process makes the material more prone to fracture, thus increasing processing difficulties. Even assuming processing can proceed without fracture, large ripples (ears) are likely to form at the edges of the resulting drawn part. This is especially true in deep-drawing processes where the depth is greater than the diameter of the punch, requiring multi-stage drawing, which makes the ears particularly prone to becoming large. Large ears not only damage the shape of the drawn part but also cause adjacent ears to overlap or crack between them during the drawing process. Furthermore, large ears necessitate an additional process to remove them from the drawn part; therefore, copper alloy sheets capable of reducing the ears formed at the edges of the drawn part are needed.

[0009] Regarding this point, the Cu-Cr-Ti-Si alloy described in Patent Document 1 exhibits high anisotropy due to its large proportion of aggregation along the Brass, S, and Copper orientations, which form the processing texture. However, Patent Document 1 does not conduct any research on the impact of anisotropy in all directions on deep drawing, nor does it disclose the simultaneous achievement of reducing the ears formed at the edges of the deep-drawn product and excellent bending workability, nor does it show evaluation results for these characteristics. In this respect, the Cu-Cr-Ti-Si alloy of Patent Document 1 exhibits high anisotropy due to its large proportion of aggregation along the Brass, S, and Copper orientations; therefore, when this copper alloy is used for deep drawing, large ears are formed at the edges of the resulting deep-drawn product.

[0010] Furthermore, regarding the Cu-Cr-(Zr,Ti) alloy described in Patent Document 2, the proportion of aggregate along the Copper orientation is particularly large, exceeding 20%, and the proportion along the Brass orientation can reach 40%, thus exhibiting high anisotropy. However, Patent Document 2 does not conduct any research on the impact of anisotropy in all directions on deep drawing, nor does it disclose the simultaneous achievement of reducing ear formation at the edges of deep-drawn products and excellent bending workability, nor does it show evaluation results for these characteristics. In this regard, the Cu-Cr-(Zr,Ti) alloy in Patent Document 2 has a large proportion of aggregate along the Copper orientation and exhibits high anisotropy; therefore, even when this copper alloy is used for deep drawing, ear formation is easily formed at the edges of the resulting deep-drawn products. In addition, the proportion of aggregate along the Cube orientation in the Cu-Cr-(Zr,Ti) alloy in Patent Document 2 is small, less than 10%; therefore, under harsh bending conditions, wrinkles are easily formed in the processed portion, and cracking is likely to occur, resulting in low bending workability.

[0011] Furthermore, regarding the Cu-Cr-Ti-Si alloy described in Patent Document 1 and the Cu-Cr-(Zr,Ti) alloy described in Patent Document 2, even from the perspective of the manufacturing method, it is a method of cold rolling immediately after hot rolling, rather than a method of intermediate annealing after the hot rolling process to add Cr and the like into the precipitate.

[0012] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a copper alloy sheet that has excellent bending workability and excellent deep drawing workability, especially reducing the ear-like structures formed at the edges of the deep-drawn articles.

[0013] Methods for solving problems The inventors of this application discovered that, in a copper alloy sheet comprising an alloy containing Cr in the range of 0.10% by mass to 1.00% by mass, with the balance including Cu and unavoidable impurities, in the EBSD method described later, the proportion of the total area of ​​grains oriented along the Brass orientation, S orientation, and Copper orientation, respectively, to the area of ​​the measurement region (hereinafter, sometimes simply referred to as "the proportion of the total area of ​​grains oriented along the Brass orientation, S orientation, and Copper orientation") is in the range of 25% to 38%, and along {001} <100> The proportion of the area of ​​the cube-oriented grains in the area of ​​the measurement region (hereinafter, sometimes simply referred to as "the proportion of the area of ​​the cube-oriented grains") is 12% or more, thereby giving the copper alloy sheet excellent bending workability and improving deep drawing workability, especially reducing the ears formed at the edges of the deep-drawn workpiece, thus completing the present invention.

[0014] That is, the features of the present invention are as described below.

[0015] (1) A copper alloy sheet having an alloy composition containing Cr in the range of 0.10% by mass to 1.00% by mass, with the balance including Cu and unavoidable impurities, and in a crystal orientation analysis based on the EBSD method performed in the measurement area of ​​the rolled surface of the aforementioned copper alloy sheet, along {011} <211> Brass orientation, {123} <634> S-orientation and {112} <111> The total area of ​​the grains oriented in the Copper orientation accounts for more than 25% and less than 38% of the area of ​​the aforementioned measurement region, and along {001} <100> The area of ​​the Cube-oriented grains accounts for more than 12% of the area of ​​the aforementioned measurement region.

[0016] (2) The copper alloy sheet as described in (1) above, wherein the average grain size of the grains in the aforementioned rolled surface is less than 15 μm.

[0017] (3) The copper alloy sheet as described in (1) or (2) above, wherein the aforementioned alloy composition further contains at least one arbitrary additive component selected from the group consisting of Mg, Sn, Zn, Fe, Si and Zr in a total range of 0.05% by mass and 0.50% by mass.

[0018] (4) The copper alloy sheet as described in any one of (1) to (3) above is used as the base plate for deep drawing.

[0019] (5) A deep-drawn product, which is obtained by deep drawing the copper alloy sheet described in any one of (1) to (3) above.

[0020] Invention Effects According to the present invention, a copper alloy sheet can be provided that has excellent bending workability and can improve deep drawing workability, especially reducing the ears formed at the edges of deep-drawn articles. Attached Figure Description

[0021] [ Figure 1 ] Figure 1 This diagram illustrates the approximate location of the ear (corrugation) formed at the edge of the deep-drawn copper alloy sheet when the rolling direction is set to 0° and rotated clockwise every 45°. It is a top view of the original copper alloy sheet before deep drawing, showing eight line segments extending radially from the center of the bottom surface in the deep-drawn sheet to the outline of a circle.

[0022] [ Figure 2 ] Figure 2 Is using Figure 1 The diagram shows a perspective view of a deep-drawn workpiece made from copper alloy sheet, illustrating the height from the bottom surface of the deep-drawn workpiece to the position of the lugs present at the upper edge.

[0023] Explanation of reference numerals in the attached figures 1. Deep-drawn products 11. Bottom surface of deep-drawn products 12. Side of deep-drawn products 13. Edges of deep-drawn products C is the center of the bottom surface of the deep-drawn product. H0, H 45 H 90 H 135 H 180 H 225 H 270H 315 Height from bottom to edge L1~L8 are the line segments drawn on the bottom surface of the deep-drawn product. X Rolling direction of copper alloy sheet Detailed Implementation

[0024] Next, embodiments of the present invention will be described. The following description illustrates examples of embodiments of the present invention and does not limit the scope of protection of the claims.

[0025] The copper alloy sheet according to the present invention has an alloy composition containing Cr in the range of 0.10% by mass to 1.00% by mass, with the balance including Cu and unavoidable impurities. In a crystal orientation analysis based on the EBSD method performed in the measurement area of ​​the rolled surface of the copper alloy sheet, along {011}... <211> Brass orientation, {123} <634> S-orientation and {112} <111> The proportion of the total area of ​​the Copper-oriented grains is in the range of 25% to 38%, and along {001} <100> The area of ​​the Cube-oriented grains is more than 12%.

[0026] The copper alloy sheet of the present invention contains at least a suitable amount of Cr and is manufactured under suitable manufacturing conditions to suppress the growth of coarse grains. As a result, the proportion of the total area of ​​grains oriented along the Brass, S, and Copper orientations becomes relatively small, ranging from 25% to 38%, while the proportion of the area of ​​grains oriented along the Cube orientation becomes relatively large, at 12% or more. This reduces anisotropy and thus reduces the ears formed at the edges of the drawn product, i.e., the ripples at the edges of the drawn product. Therefore, by adopting the above configuration, the present invention can provide a copper alloy sheet and a drawn product using the same, which, even for Cu-Cr alloys with insufficient elongation that are unsuitable for complex processing, exhibits excellent bending workability and excellent deep-drawing workability, particularly reducing the ears formed at the edges of the drawn product.

[0027] Regarding this, the bending and deep-drawing workability of copper alloy sheets varies significantly depending on the anisotropy of the copper alloy sheet, i.e., its crystal orientation. It is well known that bending workability can be improved by increasing grain size towards the cube orientation. However, conventional Cu-Cr alloys rarely exhibit cube orientation, and the area of ​​grains oriented towards the cube orientation is usually less than 1%, resulting in poor bending workability. Furthermore, regarding deep-drawing workability, there is a tendency that the less anisotropic the material, the more difficult it is for the ears to develop at the edges of the deep-drawn product. However, conventional Cu-Cr alloys have strong orientations towards the Brass, S, and Copper orientations, which serve as processing textures, thus also resulting in poor deep-drawing workability. In this regard, the copper alloy sheet of the present invention reduces the orientation of grains towards the Brass, S, and Copper orientations and increases the orientation of grains towards the cube orientation, thereby enabling grains oriented towards various crystal orientations to exist at approximately the same degree. As a result, excellent bending workability and excellent deep-drawing workability can be achieved simultaneously.

[0028] [1] Alloy composition of copper alloy plates The copper alloy sheet of the present invention has an alloy composition containing Cr as a mandatory component in the range of 0.10% by mass to 1.00% by mass. Since the copper alloy sheet of the present invention has an alloy composition of a Cu-Cr based alloy containing at least a suitable amount of Cr, it exhibits not only excellent bending workability and excellent deep drawing workability, but also high tensile strength and high electrical conductivity.

[0029] The reasons for limiting the alloy composition of copper alloy plates are explained below.

[0030] (Cr: ≥0.10% by mass to ≤1.00% by mass) Chromium (Cr) is an important component that improves the material strength of copper alloy sheets, and is present in an amount ranging from 0.10% to 1.00% by mass. When the Cr content is less than 0.10% by mass, the desired material strength cannot be obtained. Furthermore, if the Cr content is greater than 1.00% by mass, coarse second phases are easily formed, which can easily become the initiation point for cracks during deep drawing. Therefore, from the viewpoint of improving the material strength of copper alloy sheets and making it difficult for cracks to form in deep-drawn products, a Cr content ranging from 0.10% to 1.00% by mass is preferred, and more preferably from 0.20% to 0.80% by mass, and more preferably from 0.30% to 0.70% by mass.

[0031] <Add any ingredients> Furthermore, the alloy composition of the copper alloy sheet of the present invention may contain at least one component selected from the group consisting of Mg, Sn, Zn, Fe, Si and Zr as an optional additive in a range of 0.05% by mass to 1.00% by mass.

[0032] (Mg: ≥0.10% by mass and ≤0.30% by mass) Magnesium (Mg) is a component that improves stress-relieving properties. To achieve this effect, it is preferable to set the Mg content to 0.10% by mass or more. On the other hand, if the Mg content exceeds 0.30% by mass, there is a tendency for a decrease in conductivity. Therefore, the Mg content is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

[0033] (Sn: 0.10% by mass or more, 0.30% by mass or less) Sn (tin) is a component that improves stress-relieving properties. To achieve this effect, the Sn content is preferably set to 0.10% by mass or more. On the other hand, if the Sn content is greater than 0.30% by mass, there is a tendency for decreased conductivity. Therefore, the Sn content is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

[0034] (Zn: ≥0.10% by mass and ≤0.50% by mass) Zinc (Zn) is a component that improves the adhesion and migration properties of Sn plating. To achieve this effect, it is preferable to set the Zn content to 0.10% by mass or more. On the other hand, if the Zn content is greater than 0.50% by mass, there is a tendency for a decrease in conductivity. Therefore, the Zn content is preferably in the range of 0.10% by mass or more and 0.50% by mass or less.

[0035] (Fe: ≥0.05% by mass and ≤0.30% by mass) Fe (iron) is a component that has the function of suppressing grain coarsening after dynamic recrystallization in the hot rolling process [process 3] described later, and preventing surface roughness of the drawn product. To achieve this function, the Fe content is preferably set to 0.05% by mass or more. However, if the Fe content is greater than 0.30% by mass, it becomes easier to generate coarse crystals containing Fe during casting, thus becoming an easy initiation point for cracks. Therefore, the Fe content is preferably in the range of 0.05% by mass or more and 0.30% by mass or less.

[0036] (Si: ≥0.05% by mass and ≤0.30% by mass) Silicon (Si) is a component that improves the tensile strength of copper alloy sheets. To achieve this effect, the Si content is preferably set to 0.05% by mass or more. However, if the Si content exceeds 0.30% by mass, coarse Si-containing crystals are more likely to form during casting, thus increasing the likelihood of crack initiation. Therefore, the Si content is preferably in the range of 0.05% by mass to 0.30% by mass.

[0037] (Zr: ≥0.05% by mass and ≤0.30% by mass) Zirconium (Zr) is a component that serves to suppress grain coarsening after dynamic recrystallization in the hot rolling process [process 3] described later, and to prevent surface roughness of the drawn product. To achieve this effect, the Zr content is preferably set to 0.05% by mass or more. However, if the Zr content is greater than 0.30% by mass, it becomes easier to generate coarse crystals containing Zr during casting, thus making it easier to form crack initiation points. Therefore, the Zr content is preferably in the range of 0.05% by mass or more and 0.30% by mass or less.

[0038] (Total content of any added ingredients: ≥0.05% by mass and ≤1.00% by mass) To obtain the effects brought about by the aforementioned optional additives, it is preferable to contain 0.05% by mass or more of these optional additives in total, and more preferably 0.10% by mass or more of these optional additives. On the other hand, if a large amount of these optional additives are contained, the conductivity will decrease. Therefore, the total content of the optional additives is preferably set to 1.00% by mass or less, and more preferably 0.50% by mass or less.

[0039] (Balance: Cu and unavoidable impurities) The Cu alloy constituting the copper alloy sheet has an alloy composition that, in addition to the components mentioned above, includes Cu (copper) and unavoidable impurities in the balance. It should be noted that the term "unavoidable impurities" here generally refers to the following: substances present in the raw materials of metal products, substances that are unavoidably mixed in during the manufacturing process, substances that are not originally desired but are permissible due to their trace amounts and non-affecting nature on the properties of the metal product. Examples of components that can be considered unavoidable impurities include, for example, non-metallic elements such as sulfur (S), carbon (C), and oxygen (O), and metallic elements such as antimony (Sb). It should be noted that the upper limit of the content of these components can be set, for example, at 0.05% by mass for each of the above-mentioned components, and 0.20% by mass for the total amount of the above-mentioned components.

[0040] [2] The proportion of the total area of ​​grains oriented along Brass, S and Copper orientations Regarding the copper alloy sheet of the present invention, in the crystal orientation analysis based on the EBSD method performed in the measurement area of ​​the rolled surface of the copper alloy sheet, the crystal orientation along {011} will be respectively... <211> Brass orientation, {123} <634> S-orientation and {112} <111> The total area, calculated by adding the areas of the grains oriented along the Brass, S, and Copper orientations, accounts for a proportion of 25% to 38% of the area of ​​the measured region. For grains oriented along the Brass, S, and Copper orientations, ears are formed at the edges of the deep-drawn workpiece at angles approximately 45°, 135°, 225°, and 315° relative to the rolling direction; these ears are referred to as 45° ears. Here, by ensuring that the proportion of the total area of ​​grains oriented along the Brass, S, and Copper orientations is 38% or less, the crystal orientation of the crystalline phase becomes nearly random, reducing the anisotropy of the metal structure. Consequently, the 45° ears formed during deep drawing are reduced, or they no longer form. As a result, copper alloy sheets that can be uniformly deep-drawn without fracture can be obtained. On the other hand, if the total area of ​​grains oriented along the Brass, S, and Copper orientations exceeds 38%, the 45° ear develops significantly, thus greatly reducing the deep-drawing processability. Therefore, from the viewpoint of obtaining copper alloy sheets with excellent deep-drawing processability, the total area of ​​grains oriented along the Brass, S, and Copper orientations is preferably in the range of 25% to 38%, and more preferably in the range of 25% to 32%.

[0041] Here, the proportion of the total area of ​​grains oriented along Brass, S, and Copper orientations can be obtained from crystal orientation analysis data calculated using analysis software (TSL, OIM Analysis) based on crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA). "EBSD" is an abbreviation for Electron BackScatter Diffraction, a crystal orientation analysis technique utilizing Kikuchi line reflection electron diffraction generated when an electron beam is irradiated onto a copper plate sample within a scanning electron microscope (SEM). "OIM Analysis" is analysis software using data measured by EBSD. Measurements can be performed on the rolled surface of the copper alloy plate. The measurement area on the rolled surface is set to approximately 1000 μm × 1000 μm, and measurements can be performed with a scanning step size of 0.2 μm. Based on the crystal orientation analysis data for such a measurement area, the proportion of the total area of ​​grains oriented along Brass, S, and Copper orientations can be calculated relative to {011}. <211> Brass orientation, {123} <634> S-orientation and {112} <111> The atomic planes of grains with offset angles of 10° or less along the Copper orientation are used as the atomic planes of grains oriented along the Brass, S, and Copper orientations, respectively. Their areas are calculated, and by dividing their areas by the area of ​​the measurement region, the proportions of the areas of grains oriented along the Brass, S, and Copper orientations, and the proportion of the total area of ​​grains oriented along these orientations, can be determined. Here, regarding the determination of crystal orientation, from the viewpoint of ensuring quantification based on a large-scale measurement, the measurement can also be performed on the surface of a copper alloy plate. In this case, it is preferable to use the value obtained by averaging measurements at three or more fields of view.

[0042] Here, the area of ​​grains oriented along the Brass orientation preferably accounts for 6% or less of the area of ​​the measurement region. Furthermore, the area of ​​grains oriented along the S orientation preferably accounts for 28% or less of the area of ​​the measurement region. Additionally, the area of ​​grains oriented along the Copper orientation preferably accounts for 8% or less of the area of ​​the measurement region.

[0043] [3] The proportion of the area of ​​grains oriented along the cube orientation Regarding the copper alloy sheet of the present invention, in the crystal orientation analysis based on the EBSD method performed in the measurement area of ​​the rolled surface of the copper alloy sheet, along {001} <100> The area of ​​the cube-oriented grains accounts for more than 12% of the area of ​​the measurement region. Regarding the cube-oriented grains, ears are formed at the edges of the drawn product at angles approximately 0°, 90°, 180°, and 270° relative to the rolling direction; these ears are called "0° ears." Additionally, ears are formed at angles approximately 45°, 135°, 225°, and 315° relative to the rolling direction; these ears are called "45° ears." Here, by ensuring that the area of ​​the cube-oriented grains accounts for more than 12%, the bending workability of the copper alloy sheet can be improved. Furthermore, the portion forming the 0° ears can be expanded, while the 45° ears are relatively smaller. On the other hand, if the area of ​​the cube-oriented grains is less than 12%, it becomes difficult to improve the bending workability; therefore, cracks and deep wrinkles occur on the surface of the copper alloy sheet after bending. Therefore, from the viewpoint of obtaining copper alloy sheets with excellent bending workability, the proportion of the area of ​​grains oriented along the cube orientation is 12% or more, preferably 14% or more, and more preferably 15% or more. It should be noted that there is no particular upper limit to the proportion of the area of ​​grains oriented along the cube orientation, but from the viewpoint of preventing the process of oriented grains along the cube orientation from becoming lengthy and improving the productivity of copper alloy sheets, it can be set to, for example, 25%, or alternatively, 20%.

[0044] Here, the proportion of the area of ​​grains oriented along the Cube orientation can be obtained, similarly, from the crystal orientation analysis data calculated using analysis software (TSL, OIM Analysis) based on crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA). At this time, based on the crystal orientation analysis data, the proportion of the area of ​​grains oriented along the Cube orientation can be obtained relative to {001}. <100> The atomic planes of grains with an offset angle of less than 10° in the Cube orientation are taken as the atomic planes of grains oriented along the Cube orientation. Their areas are calculated, and their areas are divided by the area of ​​the measurement region (measurement area). This allows us to determine the proportion of the area of ​​grains oriented along the Cube orientation.

[0045] [4] Average grain size of grains in the rolled surface In the case of the copper alloy sheet of the present invention, the average grain size of the grains in the rolled surface is preferably 15 μm or less. When deep drawing the copper alloy sheet, a larger average grain size improves the deep drawing processability. However, if the average grain size of the grains in the rolled surface is greater than 15 μm, the likelihood of cracking or increased wrinkling at the bent portion increases during bending of the copper alloy sheet. Therefore, from the viewpoint of further improving the bending processability of the copper alloy sheet, the average grain size of the grains contained in the rolled surface is preferably 15 μm or less, more preferably 13 μm or less.

[0046] The average grain size of the grains in the copper alloy sheet can be determined using the cutting method specified in JIS H0501. More specifically, the rolled surface of the copper alloy sheet can be finished into a mirror finish by wet grinding and polishing. When observing the surface after etching the ground surface with a weak acid solution for several seconds using an optical microscope (OM) at 500x magnification, draw 10 parallel line segments of 100 μm each (50 mm in length in the optical microscope image) along the rolling direction in the obtained optical microscope (OM) image. Count the total number of points where each line segment intersects the grain boundary. Calculate the average length of each division of the line segment using the grain boundary using the following mathematical formula (I), and then calculate the average grain size (μm) as the average length of each division of the line segment.

[0047] The average length of each division of the line segment [μm] = 100 [μm] × 10 / (the total number of intersections between the line segment and the grain boundary) ... (I) [5] Manufacturing method of copper alloy sheet The aforementioned copper alloy sheet can be achieved by controlling the combination of alloy composition and manufacturing process, and the manufacturing process is not particularly limited. As an example of a manufacturing process that provides excellent bending workability and excellent deep drawing workability, the following method can be cited.

[0048] An example of the method for manufacturing the copper alloy sheet of the present invention is as follows: For a copper alloy raw material having an alloy composition equivalent to that of the copper alloy sheet described above, at least the following steps are performed sequentially: casting process [step 1], reheating process [step 2], hot rolling process [step 3], first intermediate annealing process [step 4], first cold rolling process [step 5], second intermediate annealing process [step 6], second cold rolling process [step 7], aging heat treatment process [step 8], third cold rolling process [step 9], and low-temperature annealing process [step 10]. In this manufacturing method, in particular, by performing intermediate annealing, which is not normally performed in Cu-Cr alloys, twice—in the first intermediate annealing process [step 4] and the second intermediate annealing process [step 6]—the crystal orientation is appropriately controlled. Therefore, the total proportion of grains oriented along the Brass orientation, S orientation, and Copper orientation, and the proportion of grains oriented along the Cube orientation, can be controlled within the aforementioned ranges.

[0049] (i) Melting and casting process [process 1] In the melting and casting process [Process 1], a copper alloy raw material having an alloy composition equivalent to the above-mentioned alloy composition is melted and cast to produce an ingot (block) of a specified shape (e.g., 30 mm thick, 100 mm wide, and 150 mm long). The melting and casting process [Process 1] preferably uses a high-frequency melting furnace, in which the copper alloy raw material is melted and cast in the atmosphere, in an inert gas atmosphere, or in a vacuum.

[0050] It should be noted that, in terms of the alloy composition of copper alloy raw materials, during the various manufacturing processes, the alloy composition of the raw materials may not be completely consistent with that of the copper alloy sheet produced, depending on the different added components that adhere to the smelting furnace or volatilize. However, the raw materials may have an alloy composition that is substantially the same as that of the copper alloy sheet.

[0051] (ii) Reheating process [Process 2] The reheating process [process 2] is a heat treatment process performed on the ingot after the casting process [process 1]. Regarding the heat treatment conditions in the reheating process [process 2], the preferred temperature is a range of 900°C to 1050°C, and the holding time at that temperature is a range of 1 hour to 10 hours. Here, if the temperature is below 900°C, dynamic recrystallization cannot occur sufficiently in the hot rolling process [process 3] described later, thus easily forming an inhomogeneous structure. On the other hand, if the temperature is above 1050°C, the grain boundaries weaken, thus easily causing cracks in the hot-rolled material after the hot rolling process [process 3].

[0052] (iii) Hot rolling process [process 3] The hot rolling process [process 3] is a process of hot rolling an ingot that has undergone a reheating process [process 2] until it reaches a specified thickness to produce hot-rolled material. The conditions for the hot rolling process [process 3] can be set under conditions that allow dynamic recrystallization to occur. For example, the rolling temperature can be set to 950°C or higher, and the total reduction rate can be set to 90% or higher. On the other hand, if dynamic recrystallization cannot occur sufficiently in the hot rolling process [process 3], the resulting copper alloy sheet is prone to forming an inhomogeneous structure.

[0053] The “reduction rate” (reduction ratio) in this specification is a percentage obtained by subtracting the cross-sectional area after rolling from the cross-sectional area before rolling, dividing the cross-sectional area before rolling by 100, and expressed by the following formula.

[0054] [Processing rate] = {([Cross-sectional area before rolling] - [Cross-sectional area after rolling]) / [Cross-sectional area before rolling]} × 100 (%) For hot-rolled materials after the hot rolling process [Process 3], surface cutting can also be performed to remove the surface. By performing surface cutting, the oxide film and defects generated in the hot rolling process [Process 3] can be removed. The conditions for surface cutting can be the usual conditions, without any particular limitation. The amount removed from the surface of the hot-rolled material by surface cutting can be appropriately adjusted based on the oxidation state of the surface, for example, it can be set to about 1 mm to 5 mm from the surface of the hot-rolled material.

[0055] (iv) First intermediate annealing process [process 4] The first intermediate annealing process [process 4] is a process of heat-treating the hot-rolled material after the hot-rolling process [process 3] according to the alloy composition.

[0056] Regarding the annealing conditions in the first intermediate annealing process [process 4], the preferred temperature is between 450°C and 650°C, and the holding time at that temperature is between 30 minutes and 2 hours. By performing heat treatment within the range of 450°C to 600°C, Cr-based precipitates are precipitated, thereby changing the solid solution state. The precipitated Cr-based precipitates exert a pinning effect on grain growth, making it difficult to induce the growth of coarse grains. As a result, it becomes less likely to induce crack formation originating from coarse grains during deep drawing. Furthermore, it is easier to induce aggregation towards the Cube orientation, which previously rarely aggregates. Additionally, various crystal orientations develop, thereby reducing anisotropy and thus minimizing the formation of ears at the edges of the deep-drawn product.

[0057] Here, if the temperature reached in the first intermediate annealing process [process 4] is below 450°C, Cr-based precipitates of sufficient size will not precipitate, thus making it difficult to induce a pinning effect on grain growth, and therefore making it easier to induce the growth of coarse grains. Conversely, if the temperature reached in the first intermediate annealing process [process 4] is above 650°C, the Cr-based precipitates undergo resolution, thus making it easier to induce the growth of coarse grains. If the temperature reached is below 450°C or above 650°C, a highly anisotropic metallic structure is formed, resulting in poor deep-drawing workability of the obtained copper alloy sheet. Especially from the viewpoint of improving the deep-drawing workability of the obtained copper alloy sheet, the temperature reached in the first intermediate annealing process [process 4] is more preferably in the range of 450°C to 600°C.

[0058] Furthermore, if the heat treatment time (holding time at the temperature) in the first intermediate annealing process [process 4] is less than 30 minutes, the grain growth becomes insufficient. On the other hand, even if the holding time at the temperature is longer than 2 hours, the changes to the grains are smaller. Therefore, longer heat treatment times than this are undesirable from a productivity point of view.

[0059] (v) First cold rolling process [Process 5] The first cold rolling process [process 5] is a process of cold rolling the hot-rolled material after the first intermediate annealing process [process 4].

[0060] The total processing rate in the first cold rolling process [process 5] is preferably set to a range of 75% to 90%. Here, when the total processing rate is less than 75% or greater than 90%, the combined proportion of grains oriented along the Brass, S, and Copper orientations increases, thereby increasing the anisotropy of the metal structure, and thus, the ears formed at the edges of the deep-drawn product become larger.

[0061] (vi) Second intermediate annealing process [Process 6] The second intermediate annealing process [process 6] is a process of heat-treating the cold-rolled material after the first cold rolling process [process 5] according to the alloy composition.

[0062] Regarding the annealing conditions in the second intermediate annealing process [process 6], the preferred temperature is between 450°C and 600°C, and the holding time at that temperature is between 30 minutes and 2 hours. By performing heat treatment within the range of 450°C to 600°C, Cr-based precipitates are further precipitated, thereby changing the solid solution state. Therefore, anisotropy can be reduced in the subsequent second cold rolling process [process 7]. Furthermore, by performing heat treatment within the range of 450°C to 600°C, static recrystallization is induced. This changes the metal microstructure from a highly anisotropic processing texture to a less anisotropic recrystallized texture, with the crystal orientation approaching randomness. Therefore, the proportion of the total area of ​​grains oriented along Brass, S, and Copper orientations can be significantly reduced compared to conventional processes. Simultaneously, the growth of Cube-oriented grains formed in the first intermediate annealing process [process 4] increases the proportion of the area of ​​grains oriented along the Cube orientation.

[0063] Here, if the temperature reached in the second intermediate annealing process [process 6] is below 450°C, the precipitation of Cr-based precipitates and changes in the metal structure will not occur. Therefore, the proportion of the total area of ​​grains oriented along the Brass, S, and Copper orientations will not decrease. On the other hand, if the temperature reached in the second intermediate annealing process [process 6] is above 600°C, the proportion of the total area of ​​grains oriented along the Brass, S, and Copper orientations will increase, while the proportion of the area of ​​grains oriented along the Cube orientation will decrease.

[0064] Furthermore, if the heat treatment time (holding time at the temperature) in the second intermediate annealing process [process 6] is less than 30 minutes, the precipitation of Cr-based precipitates and the change in the metal structure become insufficient. On the other hand, even if the holding time at the temperature is longer than 2 hours, the change in the grain size is smaller. Therefore, long heat treatment times above this are undesirable from a productivity point of view.

[0065] (vii) Second cold rolling process [Process 7] The second cold rolling process [process 7] is a process of cold rolling the cold-rolled material after the second intermediate annealing process [process 6].

[0066] The total processing rate in the second cold rolling process [process 7] is preferably set to a range of 15% to 35%, more preferably to a range of 15% to 30%. This allows the grains oriented along the Brass, S, and Copper orientations, which were significantly reduced in the second intermediate annealing process [process 6], to be moderately restored in the second cold rolling process [process 7]. Therefore, the grain orientation in the metal structure can be made closer to a random state. Here, when the total processing rate in the second cold rolling process [process 7] is less than 15%, the grain orientation in the metal structure remains almost unchanged after the second intermediate annealing process [process 6]. Furthermore, when the total processing rate in the second cold rolling process [process 7] is greater than 30%, and especially greater than 35%, the proportion of the area of ​​at least one of the grains oriented along the Brass, S, and Copper orientations, especially the proportion of the area of ​​grains oriented along the S orientation, increases.

[0067] (viii) Aging heat treatment process [process 8] The aging heat treatment process [process 8] is a process of performing precipitation strengthening on the cold-rolled material after the second cold rolling process [process 7]. Here, the conditions for the heat treatment in the aging heat treatment process [process 8] are a temperature reaching 400°C or higher but less than 500°C, and a holding time at that temperature of 1 hour or more but less than 4 hours. Here, when the temperature reaches 400°C or the holding time is less than 1 hour, precipitation strengthening becomes difficult to achieve, and thus the tensile strength of the copper alloy sheet tends to decrease. On the other hand, when the temperature reaches 500°C or the holding time is greater than 4 hours, the precipitates also coarsen, and thus the tensile strength of the copper alloy sheet tends to decrease. Especially from the viewpoint of improving tensile strength through precipitation strengthening of the copper alloy sheet, the temperature reaching 450°C or higher in the aging heat treatment process [process 8] is preferably 450°C or higher.

[0068] (ix) Third cold rolling process [process 9] The third cold rolling process [process 9] is a process of further cold rolling the cold-rolled material after the aging heat treatment process [process 8]. Here, the total processing ratio in the third cold rolling process [process 9] can be set according to the desired material strength in the copper alloy sheet, for example, preferably in the range of 5% to 30%, more preferably in the range of 5% to 25%. Here, when the total processing ratio is less than 5%, the work hardening amount becomes small, and therefore it becomes difficult to obtain the effect of improving the tensile strength of the copper alloy sheet. In addition, when the total processing ratio is greater than 25%, especially greater than 30%, the elongation of the copper alloy sheet decreases, thereby reducing at least one of the deep drawing workability and bending workability.

[0069] (x) Low-temperature annealing process [Process 10] The low-temperature annealing process [Process 10] is a process of annealing the cold-rolled material after the third cold rolling process [Process 9] by performing heat treatment. Regarding the heat treatment conditions in this low-temperature annealing process [Process 10], it is preferable that the temperature reached is in the range of 200°C to 400°C, and the holding time at that temperature is in the range of 10 seconds to 30 minutes. Here, when the temperature reached is below 200°C and the holding time is less than 10 seconds, the residual strain in the annealed cold-rolled material becomes excessive, thus reducing the deep-drawing workability of the copper alloy sheet. On the other hand, when the temperature reached is above 400°C and the holding time at that temperature is greater than 30 minutes, the work hardening based on cold rolling disappears.

[0070] [6] Applications of copper alloy plates The copper alloy sheet of the present invention is preferably used as a base plate for deep drawing. That is, the copper alloy sheet of the present invention is particularly suitable for performing deep drawing to obtain deep-drawn products, for example, suitable for forming deep-drawn parts used in electronic devices and automotive in-vehicle equipment. More specifically, it is suitable for connectors, lead frames, relays, switches, sockets, shielding covers, shielding shells, camera module shells, vibration device shells, heat dissipation components for liquid crystal and organic EL displays, batteries, probes, gas shielding valves, etc., especially for connector hold-down devices, shells, camera module shells, battery shells, shielding covers, contact probes, etc. These parts are often manufactured by combining deep drawing and bending processes, but by forming them from the copper alloy sheet of the present invention, excellent deep drawing and bending workability can be achieved simultaneously, and therefore, it can be suitable for the application of these parts. In addition, the copper alloy sheet of the present invention has a Cu-Cr alloy composition, which provides higher electrical conductivity (thermal conductivity) than brass and zinc cupronickel used in deep drawing processes. Therefore, it can also be suitable for components requiring high heat dissipation.

[0071] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, but includes all the concepts of the present invention and all the ways contained in the claims, and various changes can be made within the scope of the present invention.

[0072] Example Next, in order to make the effects of the present invention clearer, examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples.

[0073] (Examples 1-16 of this invention and Comparative Examples 1-9) A casting process [Process 1] is performed, in which various copper alloy raw materials with the alloy composition shown in Table 1 are melted and cooled in an atmospheric atmosphere to obtain an ingot. This ingot is then subjected to a reheating process [Process 2], where it is heat-treated at a reaching temperature of 950°C (heat treatment temperature) and held at that temperature for 5 hours (heat treatment time). Following this, a hot rolling process [Process 3] is performed, in which the ingot is rolled with a total machining rate of 90% or more and with the long side of the ingot as the rolling direction, to obtain a hot-rolled material. The rolled material after the hot rolling process [Process 3] is then subjected to a first intermediate annealing process [Process 4], where it is heat-treated at the reaching temperature and holding time listed in Table 2. Finally, it is cooled to room temperature by water cooling.

[0074] After cooling, the hot-rolled material is surface-cut, removing approximately 1mm to 5mm from both the inside and outside to remove the oxide film. Then, a first cold rolling process [Process 5] is performed, rolling the material at the processing rate specified in Table 2 with the long side of the hot-rolled material as the rolling direction. Next, the cold-rolled material after the first cold rolling process [Process 5] undergoes a second intermediate annealing process [Process 6], heat-treated at the temperature and holding time specified in Table 2. Finally, a second cold rolling process [Process 7] is performed, rolling the material at the processing rate specified in Table 2 with the long side of the hot-rolled material as the rolling direction.

[0075] For the cold-rolled material after the second cold rolling process [process 7], an aging heat treatment process [process 8] is performed to heat treat the material at the temperature and holding time recorded in Table 2. Then, a third cold rolling process [process 9] is performed to roll the material with the long side direction as the rolling direction under the conditions of the total processing rate recorded in Table 2, so as to obtain a rolled material with a plate thickness of 0.20 mm.

[0076] It should be noted that in Table 1, Mg (magnesium), Sn (tin), Zn (zinc), Fe (iron), Si (silicon), and Zr (zirconium), which are components other than copper (Cu) and Cr (chromium), are considered as optional additives. Additionally, in Table 1, a horizontal line “-” is drawn in the column for components not included in the alloy composition of the copper alloy raw materials, indicating that the component is not present, or even if it is present, the concentration is below the detection limit.

[0077] [Various Measurement and Evaluation Methods] Using the copper alloy sheet materials described in the above-described examples and comparative examples of the present invention, the characteristics shown below were evaluated. The evaluation conditions for each characteristic are as follows.

[0078] [1] The proportion of the total area of ​​grains oriented along Brass, S and Copper orientations The ratio of the total area of ​​grains oriented along Brass, S, and Copper orientations is based on the copper alloy plates obtained in the present invention and comparative examples. It was calculated using analysis software (TSL, OIM Analysis) based on crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA). The measurements were performed on rolled surfaces of copper alloy plates obtained by resin embedding and finishing with mechanical grinding and polishing (colloidal silica), within a field of view of approximately 1000 μm × 1000 μm, with a scanning step size of 0.2 μm.

[0079] Based on the crystal orientation analysis data obtained using the EBSD method, relative to {011} <211> Brass orientation, {123} <634> S-orientation and {112} <111> The atomic planes of grains with offset angles of less than 10° in the Copper orientation were used as the atomic planes of grains oriented along the Brass, S, and Copper orientations, respectively. Their areas were calculated, and these areas were divided by the area of ​​the measurement region (measurement area). From this, the proportions of the areas oriented along the Brass orientation (a), along the S orientation (b), along the Copper orientation (c), and the total area of ​​grains oriented along the Brass, S, and Copper orientations (a+b+c) were calculated. The results are shown in Table 3.

[0080] [2] The proportion of the area of ​​grains oriented along the cube orientation Similar to the above-mentioned [1] proportion of the total area of ​​grains oriented along Brass, S, and Copper orientations, the proportion of the area of ​​grains oriented along the Cube orientation is obtained from crystal orientation analysis data calculated using analysis software (TSL, OIM Analysis) based on crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA). At this time, based on the crystal orientation analysis data, the proportion of the area of ​​grains oriented along the Cube orientation is calculated relative to {001} <100> The atomic planes of grains with an offset angle of less than 10° in the Cube orientation are taken as the atomic planes of grains oriented along the Cube orientation. Their areas are calculated, and their areas are divided by the measured area to determine the proportion of the area of ​​grains oriented along the Cube orientation. The results are shown in Table 3.

[0081] [3] Average grain size of grains in the rolled surface The average grain size of the grains in the rolled surface of the copper alloy sheet was determined using the cutting method specified in JIS H0501. More specifically, the rolled surface of the copper alloy sheet was finished to a mirror finish through wet grinding and polishing. The surface was then observed at 500x magnification using an optical microscope (OM) after etching the ground surface with a weak acid solution for several seconds. In the obtained OM image, 10 parallel line segments of 100 μm each (50 mm in length in the OM image) were drawn along the rolling direction. The total number of points where each line segment intersects the grain boundary was counted. The average length of each zone of the line segment used to divide the grain boundaries was calculated using the following mathematical formula (I). The average grain size (μm) was then calculated as the average length of each zone of the line segment. The results are shown in Table 3.

[0082] The average length of each division of the line segment [μm] = 100 [μm] × 10 / (the total number of intersections between the line segment and the grain boundary) ... (I) [4] Evaluation of the deep drawing properties of copper alloy sheets For the deep drawing process of copper alloy sheets, a blank with a diameter of 40 mm is formed from a copper alloy sheet with a thickness of 0.2 mm obtained by die stamping. Lubricating oil (trade name: PRETON R-303P, manufactured by Sugimura Chemical Co., Ltd.) is applied to the surface of the blank. A die with a radius of curvature of 1 mm at the shoulder is installed. A punch with a diameter of 20 mm at the tip, a radius of curvature of 1 mm at the tip corner, and a gap of 0.27 mm between the punch and the die is pressed into the center of the blank. This process is performed once to obtain a cylindrical cup as a deep-drawn product.

[0083] For the resulting deep-drawn products, such as Figure 1 As shown, a line segment L1 is drawn from the center C of the bottom surface 11 of the deep-drawn workpiece 1 towards the side of the copper alloy sheet constituting the bottom surface in the rolling direction X. This line segment L1 is used as the reference angle (0°). Furthermore, the height from the bottom surface 11 to the edge 13 is measured on the side surface 12 of the deep-drawn workpiece 1 at the location where this line segment L1 abuts, and this height is taken as H0. Next, a line segment L2 is drawn from the center C of the bottom surface 11 of the deep-drawn workpiece 1 along a direction that is 45° clockwise relative to the line segment L1. The height from the bottom surface 11 to the edge 13 is measured on the side surface 12 of the deep-drawn workpiece 1 at the location where this line segment L1 abuts, and this height is taken as H. 45 Similarly, from center C, draw line segments L3 to L8 along directions that are left-handedly rotated by 90°, 135°, 180°, 225°, 270°, and 315° relative to line segment L1. For the side surface 12 of the deep-drawn workpiece 1 at the point where these line segments L3 to L8 abut, as shown... Figure 2 As shown, the height from the bottom surface 11 to the edge 13 is measured, and this height is taken as H. 90 H 135 H 180 H 225 H 270 H 315 .

[0084] Using these heights H0, H 45 H 90 H 135 H 180 H 225 H 270 H 315 The size E of the corrugation (ear) at the edge of the deep-drawn workpiece is calculated using the following formulas (II) to (IV). That is, in this embodiment, the size E of the corrugation (ear) is calculated as the ratio [%] of the difference between the average height of the side surface 12 of the deep-drawn workpiece 1 at the position where line segments L1 to L8 abut, when the average height is set to 100%, and the average height of the side surface 12 in the direction at an angle of 0°, 90°, 180°, and 270° relative to the rolling direction X from the center C, and the average height of the side surface 12 in the direction at an angle of 45°, 135°, 225°, and 315° relative to the rolling direction X.

[0085] H1=(H 45 +H 135 +H 225 +H 315 ) / 4 ……(II) H2 = (H0 + H) 90 +H 180 +H 270 ) / 4 ……(III) E=[(H1―H2) / {(H1+H2) / 2}]×100……(IV) At this point, when the ear is formed in a direction at an angle of approximately 45°, 135°, 225°, or 315° relative to the rolling direction, the size E of the ear becomes a positive number; when the ear is formed in a direction at an angle of approximately 0°, 90°, 180°, or 270° relative to the rolling direction, the size E of the ear becomes a negative number.

[0086] Furthermore, the size of the ripples (ears) at the edges of the deep-drawn parts is evaluated according to the following criteria. These criteria are based on the following: the larger the absolute value of the ear size E, the lower the deep-drawing processability; in particular, if the absolute value of the ear size E is greater than 6.0%, it becomes more prone to breakage from the ear during deep drawing. The results are shown in Table 3.

[0087] Evaluation Criteria for the Size of the Edge Wavy (Ears) of Deep-Drawn Products "1" (Excellent): The absolute value of the ear size E is less than 2.0%. "2" (Good): The absolute value of the ear size E is greater than 2.0% and less than 6.0%. "3" (Unacceptable): Cases where the absolute value of the ear size E is greater than 6.0%, and cases where the blank breaks during deep drawing. [5] Evaluation of the bending workability of copper alloy sheets For the bending workability of copper alloy sheets, test pieces with a length of 25 mm and a width of 10 mm were collected from the copper alloy sheets with the rolling direction of the substrate as the long side direction. Using a 90° bending die with a bending angle of 90 degrees and a bending radius of 0.4 mm, the test pieces were pre-bent along the Badway direction according to the Japanese Shin-Dong Association technical standard T307:2007 (Evaluation Method for Bending Workability of Copper and Copper Alloy Sheets). Then, a compression testing machine was used for close bending along the Badway direction. At this point, the presence or absence of cracks and wrinkles on the outer side of the bent area was visually observed using an optical microscope. Based on the observation results, the bending workability was evaluated according to the Japanese Shin-Dong Association technical standard T307:2007.

[0088] More specifically, the bending workability of copper alloy sheets was evaluated according to the following criteria. The results are shown in Table 3.

[0089] "1" (Excellent): Based on the evaluation criteria of A or B in the Japanese Shindō Association technical standard T307:2007.

[0090] "2" (Good): Based on the evaluation criterion of C in the Japanese Shindō Association technical standard T307:2007.

[0091] "3" (Unacceptable): Based on the evaluation criteria of D or E in the Japanese Shindō Association technical standard T307:2007. That is, a crack is confirmed on the outside of the bent part.

[0092] [6] Overall evaluation For the two evaluation results related to the deep drawing and bending workability of copper alloy sheets, a score of "1" for both results is considered excellent in both deep drawing and bending workability, and is rated "1" (Excellent). Conversely, a score of "2" for one result and "1" for the other is considered good or better in both deep drawing and bending workability, and is rated "2" (Good). On the other hand, a score of "3" for at least one result is considered unacceptable in at least one of the deep drawing and bending workability, and is rated "3" (Unacceptable). The results are shown in Table 3.

[0093] Based on the results in Tables 1 to 3, the alloy composition of the copper alloy sheets in Examples 1 to 16 of the present invention is within the suitable range of the present invention, and the proportion of the total area of ​​grains oriented along the Brass orientation, S orientation and Copper orientation is in the range of 25% to 38%, and the proportion of the area of ​​grains oriented along the Cube orientation is 12% or more. In this case, the copper alloy sheets are evaluated as “1” or “2” for both bending workability and deep drawing workability.

[0094] Therefore, the copper alloy sheets of Examples 1 to 16 of the present invention have excellent bending workability and excellent deep drawing workability, especially reducing the ears formed on the edges of the deep-drawn articles.

[0095] Examples 1-5 of this invention are examples in which the conditions for the arrival temperature and holding time of intermediate annealing in the first intermediate annealing process [process 4] and the second intermediate annealing process [process 6], and the conditions for the total processing rate in the first cold rolling process [process 5] are changed within the above-mentioned range. It is believed that since the copper alloy sheets of Examples 1-5 of this invention are copper alloy sheets that are evaluated as "1" or "2" in both bending workability and deep drawing workability, even if these conditions are changed within the above-mentioned range, the impact on the evaluation results of bending workability and deep drawing workability is small.

[0096] Furthermore, Example 6 of the present invention is an example where the total processing rate in the second cold rolling process [process 7] is as high as 33%. Regarding the copper alloy sheet of Example 6 of the present invention, since the proportion (b) of the area of ​​grains oriented along the S orientation is higher than in other examples of the present invention, the evaluation of its deep drawing processability is rated as "2".

[0097] Furthermore, Example 7 of the present invention is an example where the total processing rate in the third cold rolling process [process 9] is as high as 30%. Regarding the copper alloy sheet of Example 7 of the present invention, since the proportion of the area of ​​grains oriented along the Cube orientation is lower than in other examples of the present invention, the evaluation of bending workability is rated as "2".

[0098] In the case of the copper alloy sheet of Examples 8 to 11 of the present invention, by optimizing the intermediate annealing conditions in the first intermediate annealing process [process 4] and the second intermediate annealing process [process 6], and the total processing rate in the first cold rolling process [process 5], the second cold rolling process [process 7] and the third cold rolling process [process 9], the average grain size of the grains contained in the rolled surface is reduced, and the proportion of the area of ​​grains oriented along the cube orientation is increased. Therefore, both the evaluation of bending workability and the evaluation of deep drawing workability are evaluated as "1".

[0099] Furthermore, the copper alloy plates of Examples 11 to 16 of the present invention contain one or more arbitrary additives. Even in this case, when the total content of the arbitrary additives is in the range of 0.05% by mass to 1.00% by mass, they are at least good in terms of bending workability and deep drawing workability.

[0100] On the other hand, in all of the copper alloy sheets of Comparative Examples 1 to 9, the total area of ​​grains oriented along the Brass, S, and Copper orientations is greater than 38%, and the area of ​​grains oriented along the Cube orientation is less than 12%. Therefore, the copper alloy sheets of Comparative Examples 1 to 9 are copper alloy sheets that are rated as "3" in one or both of the evaluation of bending workability and deep drawing workability.

[0101] In particular, regarding the copper alloy sheet of Comparative Example 1, the arrival temperature in the first intermediate annealing process [process 4] was low, and the evaluation of bending workability was rated as "3".

[0102] Furthermore, regarding the copper alloy sheet of Comparative Example 2, the intermediate annealing temperature reached in the second intermediate annealing process [process 6] was high, and the evaluation of bending workability and deep drawing workability was both rated as "3".

[0103] Furthermore, regarding the copper alloy sheets of Comparative Examples 3 and 4, the total processing rate in the first cold rolling process [process 5] was outside the aforementioned suitable range, and the evaluation of bending workability and deep drawing workability was both rated as "3".

[0104] In addition, regarding the copper alloy sheet of Comparative Example 5, the holding time at the temperature reached in the first intermediate annealing process [process 4] was long, and the evaluation of bending workability and deep drawing workability were both rated as "3".

[0105] Furthermore, regarding the copper alloy sheet of Comparative Example 6, the holding time at the temperature reached in the first intermediate annealing process [process 4] is long, and the holding time at the temperature reached in the second intermediate annealing process [process 6] is short, so the evaluation of its deep drawing workability is rated as "3".

[0106] Furthermore, regarding the copper alloy sheets of Comparative Examples 7 and 8, the total processing rate in the third cold rolling process [process 9] was outside the above-mentioned suitable range, and the evaluation of bending workability and deep drawing workability was both rated as "3".

[0107] Furthermore, regarding the copper alloy sheet of Comparative Example 9, the total processing rate in the second cold rolling process [process 7] is large, and the evaluation of deep drawing workability is rated as "3".

Claims

1. A copper alloy sheet having an alloy composition comprising Cr in the range of 0.10% by mass to 1.00% by mass, with the balance including Cu and unavoidable impurities. In the crystal orientation analysis based on the EBSD method performed in the measurement area of ​​the rolled surface of the copper alloy sheet, Along {011} respectively <211> Brass orientation, {123} <634> S orientation and {112} <111> The total area of ​​the copper-oriented grains accounts for more than 25% and less than 38% of the area of ​​the measured region, and Along {001} <100> The area of ​​the cube-oriented grains accounts for more than 12% of the area of ​​the measurement region.

2. The copper alloy sheet as described in claim 1, wherein, The average grain size of the grains in the rolled surface is less than 15 μm.

3. The copper alloy sheet as described in claim 1, wherein, The alloy composition further includes at least one arbitrary additive component selected from the group consisting of Mg, Sn, Zn, Fe, Si and Zr, in a total range of 0.05% by mass to 1.00% by mass.

4. The copper alloy sheet as described in any one of claims 1 to 3, which is used as the base plate for deep drawing.

5. A deep-drawn product obtained by deep drawing a copper alloy sheet as described in any one of claims 1 to 3.

Images