Copper alloy sheet material, bent product, and stretched product

Abstract

The copper alloy sheet has an alloy composition containing from 1.00 mass% to 5.00 mass% (inclusive) of Ni and from 0.20 mass% to 1.50 mass% (inclusive) of Si, with the remainder being Cu and unavoidable impurities. When the BR orientation {362} lt as measured by the EBSD method; 853gt, 853gt; the area ratio is set as [BR], and the Copper orientation {121} lt; 1 < 1 > gt; the area ratio is set as [C], and S orientation {231} lt; 346gt, 346gt; the area ratio is set as [S], and the Brass orientation {1 < 0 >} lt; 1 12gt; the area ratio is set as [B], and the Cube orientation {100} lt; 0 < 1 gt >; the area ratio is set as [W], and the RD-Rotate-Cube orientation {0 1 2} lt; 100gt, 100gt; the area ratio is set as [RDW], and Goss orientation {011} lt; 100gt, 100gt; when the surface area ratio is [G], the ratio ([BR] + [C] + [S] + [B]) / ([W] + [RDW] + [G]) of the surface area ratio in the crystal orientation is 1.4-3.0, and [W] is 5.0%-20.0%.

Description

Technical Field

[0001] This disclosure relates to a copper alloy sheet, a bent product, and a stretched product. Background Technology

[0002] To date, Cu-Ni-Si alloys have been specifically used for bending processes for connectors, and various improvements have been made through crystal orientation control. On the other hand, there are fewer reports on Cu-Ni-Si alloys with excellent tensile workability.

[0003] For example, Patent Document 1 describes a copper alloy plate in which, in the crystal orientation analysis of electron back-scattered diffraction (EBSD) measurements, when the area ratios of the aggregate orientation components of the BR orientation {3 6 2}<8 53>, RD-Rotated-Cube orientation {0 1 2}<1 0 0>, Cube orientation {1 0 0}<0 0 1>, Copper orientation {1 2 1}<1 1 1>, S orientation {2 3 1}<3 4 6>, and Brass orientation {1 1 0}<1 1 2> are set as [BR], [RDW], [W], [C], [S], and [B], respectively, it is defined as R = ([BR] + [RDW] + [W]) / ([C] + [S] + [B]) with an R value of 1 or higher, and a strength of 500. With a strength of over MPa and a conductivity of over 30% IACS, it exhibits excellent bending workability and strength. However, while bending workability is discussed in Patent Document 1, tensile workability is not.

[0004] Furthermore, stretching processes are mainly divided into circular stretching and corner stretching. When corner stretching is performed, the corner is stretched while the straight section is bent. Therefore, it is necessary to consider both bending and stretching workability. However, while bending and stretching workability have been discussed separately, no copper alloy sheet that combines both has been reported to date.

[0005] The Cu-Ni-Si alloys reported to date for bending processes exhibit strong anisotropy, leading to significant lug development during stretching. Lug growth not only damages the shape of the workpiece but can also cause wrinkles to form between the lug troughs during processing, potentially initiating cracks. Furthermore, an additional process is required after final processing to remove the lugs. Therefore, lug growth is undesirable, and suppressing lug growth is crucial for improving stretching workability. Consequently, directly using the Cu-Ni-Si alloys currently used for bending processes for stretching is not ideal.

[0006] Furthermore, composite processing combining stretching and bending is applied to stretched products such as connectors, lead frames, relays, switches, sockets, shielding boxes, shielding cans, camera module housings, vibration device housings, heat dissipation components for liquid crystal or organic electroluminescence (EL) displays, batteries, and gas shielding valves for electronic devices or automotive applications (vehicle-mounted). With the increasing performance, high current, and miniaturization of electronic and automotive equipment in recent years, the requirements for the stretching and bending properties of these products are now much higher than before.

[0007] [Previous Technical Documents]

[0008] (Patent Documents)

[0009] Patent Document 1: International Publication No. 2011 / 068135 Summary of the Invention

[0010] [The problem the invention aims to solve]

[0011] The purpose of this disclosure is to provide a copper alloy sheet that combines excellent tensile and bending workability, as well as bent and tensile articles using the copper alloy sheet.

[0012] [Technical means to solve the problem]

[0013] [1] A copper alloy plate having the following alloy composition: containing 1.00% by mass and 5.00% by mass of Ni and 0.20% by mass and 1.50% by mass of Si, with the remainder being Cu and unavoidable impurities; when the area ratio of the BR orientation {3 6 2}<8 5 3> determined by the EBSD method is set as [BR], the area ratio of the Copper orientation {1 2 1}<1 1 1> is set as [C], the area ratio of the S orientation {2 3 1}<3 4 6> is set as [S], the area ratio of the Brass orientation {1 1 0}<1 1 2> is set as [B], the area ratio of the Cube orientation {1 0 0}<0 0 1> is set as [W], the area ratio of the RD-Rotated-Cube orientation {0 12}<1 0 0> is set as [RDW], and the area ratio of the Goss orientation {0 1 1}<1 0 When the area ratio of 0> is set to [G], the ratio of the area ratio of the crystal orientation γ, i.e. ([BR]+[C]+[S]+[B]) / ([W]+[RDW]+[G]), is 1.4 or more and 3.0 or less, and [W] is 5.0% or more and 20.0% or less.

[0014] [2] According to the copper alloy sheet described in [1] above, wherein the average grain size in the cross section perpendicular to the rolling direction of the aforementioned copper alloy sheet is less than 30 μm.

[0015] [3] The copper alloy sheet according to [1] or [2] above, wherein the aforementioned alloy composition further contains one or more elements selected from the group consisting of Sn, Zn, Mg, Fe and Cr, in a total of more than 0.05% by mass and less than 1.00% by mass.

[0016] [4] A bent product using a copper alloy sheet as described in any one of [1] to [3] above.

[0017] [5] A drawn article using a copper alloy sheet as described in any one of [1] to [3] above.

[0018] (The effect of the invention)

[0019] According to this disclosure, a copper alloy sheet that combines excellent tensile and bending workability can be provided, as well as bent and stretched articles using the copper alloy sheet. Attached Figure Description

[0020] Figure 1 is a schematic diagram illustrating an example of a drawn workpiece used to explain the lug ratio.

[0021] Figure 2 is a schematic diagram illustrating an example of the bottom surface of a drawn workpiece with a lug ratio.

[0022] Figure 3 is a graph showing the relationship between the ratio γ and the lug ratio of the embodiments and comparative examples that can be stretched without cracking. Detailed Implementation

[0023] The implementation method will be described in detail below.

[0024] Through repeated and diligent research, the inventors discovered that by having a specific alloy composition and by controlling the ratio γ of the area ratio of each crystal orientation and the area ratio [W] of the Cube orientation {1 0 0}<0 0 1> within a specific range, copper alloy sheets can achieve both excellent tensile and bending workability. Based on the aforementioned insights, this disclosure was completed.

[0025] The copper alloy sheet of the embodiment has the following alloy composition: containing 1.00% by mass or more and 5.00% by mass or less of Ni and 0.20% by mass or more and 1.50% by mass or less of Si, the balance being Cu and inevitable impurities; when the area ratio of the BR orientation {3 6 2}<8 5 3> measured by the EBSD method is [BR], the area ratio of the Copper orientation {1 2 1}<1 1 1> is [C], the area ratio of the S orientation {2 3 1}<3 4 6> is [S], the area ratio of the Brass orientation {1 1 0}<1 1 2> is [B], the area ratio of the Cube orientation {1 0 0}<0 0 1> is [W], the area ratio of the RD-Rotated-Cube orientation {0 1 2}<1 0 0> is [RDW], and the area ratio of the Goss orientation {0 1 1}<1 0 0> is [G], the ratio γ of the area ratios of the crystal orientations, that is, ([BR] + [C] + [S] + [B]) / ([W] + [RDW] + [G]), is 1.4 or more and 3.0 or less, and [W] is 5.0% or more and 20.0% or less.

[0026] First, the alloy composition of the copper alloy sheet will be described.

[0027] The copper alloy sheet of the above embodiment has the following alloy composition: containing 1.00% by mass or more and 5.00% by mass or less of Ni and 0.20% by mass or more and 1.50% by mass or less of Si, the balance being Cu and inevitable impurities.

[0028] <Ni: 1.00% by mass or more and 5.00% by mass or less>

[0029] If the content of Ni (nickel) is 1.00% by mass or more, the strength of the copper alloy sheet can be relatively high. In addition, if the content of Ni is 5.00% by mass or less, the reduction in conductivity can be suppressed. Further, the formation of a coarse second phase, which is a compound of Ni and Si, can be suppressed, thereby improving the drawing processability. The coarse second phase easily becomes the starting point of cracks during the drawing process. Therefore, regarding the content of Ni, the lower limit is 1.00% by mass or more, preferably 1.50% by mass or more, more preferably 2.00% by mass or more, and the upper limit is 5.00% by mass or less, preferably 4.50% by mass or less, more preferably 4.00% by mass or less.

[0030] <Si: 0.20% by mass or more and 1.50% by mass or less>

[0031] If the content of Si (silicon) is 0.20 mass% or more, the strength of the copper alloy sheet can be made relatively high. In addition, if the content of Si is 1.50 mass% or less, the decrease in conductivity can be suppressed, and further, the formation of a coarse second phase, which is a compound of Ni and Si, can be suppressed, thereby improving the drawing processability. Therefore, regarding the content of Si, the lower limit is 0.20 mass% or more, preferably 0.30 mass% or more, more preferably 0.50 mass% or more, and the upper limit is 1.50 mass% or less, preferably 1.10 mass% or less, more preferably 1.00 mass% or less.

[0032] <Sub-components of the copper alloy sheet: 0.05 mass% or more and 1.00 mass% or less>

[0033] The alloy composition of the copper alloy sheet may further contain one or more elements selected from the group consisting of Sn, Zn, Mg, Fe, and Cr, with a total content of 0.05 mass% or more and 1.00 mass% or less. That is, in addition to the essential basic components Ni and Si, the copper alloy sheet may further contain one or more components selected from the group consisting of Sn, Zn, Mg, Fe, and Cr, with a total content of 0.05 mass% or more and 1.00 mass% or less, as optional components, that is, sub-components.

[0034] <Sn: 0.10 mass% or more and 0.30 mass% or less>

[0035] If the content of Sn (tin) is 0.10 mass% or more, the stress relaxation resistance characteristics of the copper alloy sheet can be improved. If the content of Sn is 0.30 mass% or less, the decrease in conductivity of the copper alloy sheet can be suppressed. Therefore, the content of Sn is preferably 0.10 mass% or more and 0.30 mass% or less.

[0036] <Zn: 0.10 mass% or more and 0.50 mass% or less>

[0037] If the content of Zn (zinc) is 0.10 mass% or more, the adhesion and migration characteristics of Sn plating can be improved. If the content of Zn is 0.50 mass% or less, the decrease in conductivity of the copper alloy sheet can be suppressed. Therefore, the content of Zn is preferably 0.10 mass% or more and 0.50 mass% or less.

[0038] <Mg: 0.10 mass% or more and 0.30 mass% or less>

[0039] If the content of Mg (magnesium) is 0.10 mass% or more, the stress relaxation resistance characteristics of the copper alloy sheet can be improved. If the content of Mg is 0.30 mass% or less, the decrease in conductivity of the copper alloy sheet can be suppressed. Therefore, the content of Mg is preferably 0.10 mass% or more and 0.3`0 mass% or less.

[0040] <Fe: 0.05 mass% or more and 0.30 mass% or less>

[0041] If the content of Fe (iron) is 0.05 mass% or more, the grain growth after dynamic recrystallization in hot rolling can be suppressed, and the surface roughness of the drawn product can be suppressed. If the content of Fe is 0.30 mass% or less, the formation of coarse Fe-containing crystals during casting is suppressed, and thus the drawability is improved. Coarse Fe-containing crystals are likely to become the starting point of cracks during drawing. Therefore, the content of Fe is preferably 0.05 mass% or more and 0.30 mass% or less.

[0042] <Cr: 0.05 mass% or more and 0.30 mass% or less>

[0043] If the content of Cr (chromium) is 0.05 mass% or more, the grain growth after dynamic recrystallization in hot rolling can be suppressed, and the surface roughness of the drawn product can be suppressed. If the content of Cr is 0.30 mass% or less, the formation of coarse Cr-containing crystals during casting is suppressed, and thus the drawability is improved. Coarse Cr-containing crystals are likely to become the starting point of cracks during drawing. Therefore, the content of Cr is preferably 0.05 mass% or more and 0.30 mass% or less.

[0044] <The balance: Cu and unavoidable impurities>

[0045] The balance other than the above components is Cu (copper) and unavoidable impurities. Unavoidable impurities refer to impurities contained at an unavoidable level in the manufacturing process. The content of unavoidable impurities may be the main cause affecting the properties of the copper alloy sheet, and therefore, it is preferably that the content of unavoidable impurities is small. As unavoidable impurities, for example, non-metallic elements such as S (sulfur), C (carbon), O (oxygen), and elements such as Sb (antimony) can be cited. In addition, the upper limit value of the content of unavoidable impurities for each of the above elements is preferably 500 ppm or less, and the total of the above elements is preferably 2000 ppm or less.

[0046] Next, the area ratio of the aggregate texture orientation components of the copper alloy sheet will be described.

[0047] For copper alloy plates, the area ratio of the BR orientation {3 6 2}<8 5 3> determined by the EBSD method is set as [BR], the area ratio of the Copper orientation {1 2 1}<1 1 1> is set as [C], the area ratio of the S orientation {2 3 1}<3 4 6> is set as [S], the area ratio of the Brass orientation {1 1 0}<1 1 2> is set as [B], the area ratio of the Cube orientation {1 0 0}<0 0 1> is set as [W], the area ratio of the RD-Rotated-Cube (hereinafter also referred to as RDW) orientation {0 1 2}<1 0 0> is set as [RDW], and the area ratio of the Goss orientation {0 1 1}<1 0 When the area ratio of 0> is set to [G], the ratio of the area ratio of the crystal orientation γ, i.e. ([BR]+[C]+[S]+[B]) / ([W]+[RDW]+[G]), is 1.4 or more and 3.0 or less, and [W] is 5.0% or more and 20.0% or less.

[0048] The S-direction is sometimes also called the R-direction. The index of the S-direction can sometimes be expressed as {1 2 3}<4 1 2> instead of {23 1}<3 4 6>. Since they are roughly the same direction, they have almost no effect.

[0049] Regarding the aforementioned crystal orientations, the BR orientation {3 6 2}<8 5 3>, the Copper orientation {1 2 1}<1 1 1>, the S orientation {2 3 1}<3 4 6>, and the Brass orientation {1 1 0}<1 1 2> produce lugs at angles of approximately 45°, 135°, 225°, and 315° relative to the rolling direction of the copper alloy sheet. Hereinafter, these lugs will also be referred to as 45° lugs.

[0050] On the other hand, lugs are generated in the Cube orientation {1 0 0}<0 0 1>, RD-Rotated-Cube orientation {0 1 2}<1 0 0>, and Goss orientation {0 1 1}<1 0 0> at angles of 0°, 90°, 180°, and 270° relative to the rolling direction of the copper alloy sheet. Hereinafter, these lugs will also be referred to as 0° lugs.

[0051] The direction of the lug formation is related to the ratio γ of the area ratio of the crystal orientation. The lug rate can be suppressed by controlling the ratio γ within a specific range.

[0052] Figure 1 is a schematic diagram showing an example of a drawn workpiece used to illustrate the lug ratio. Figure 2 is a schematic diagram showing an example of the bottom surface of a drawn workpiece used to illustrate the lug ratio. On the bottom surface of the drawn workpiece shown in Figure 2, the direction parallel to the rolling direction of the copper alloy sheet is set to 0°. Using the bottom surface as a reference, the heights from the bottom surface to the upper edge of the drawn workpiece at positions of 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° are set as H0, H45, H90, H135, H180, H225, H270, and H315, respectively. The lug ratio can be calculated using the following formula.

[0053] H1=(H45+H135+H225+H315) / 4

[0054] H2=(H0+H90+H180+H270) / 4

[0055] Protrusion rate = 100 × (H1 - H2) / {(H1 + H2) / 2}

[0056] When a lug appears at positions of 45°, 135°, 225°, and 315°, the lug rate is positive; when a lug appears at positions of 0°, 90°, 180°, and 270°, the lug rate is negative.

[0057] Here, the bending or stretching workability of copper alloy sheets varies significantly depending on their anisotropy, i.e., the different crystal orientations. It is well known that bending workability is improved by agglomeration towards the cube orientation. However, agglomeration towards a specific orientation leads to increased material anisotropy, thus increasing the size of the stretching lugs. On the other hand, regarding stretching, it is known that fewer cube orientations result in less breakage during processing, thus improving stretching workability. Therefore, to balance stretching and bending workability, it is preferable to reduce agglomeration towards specific crystal orientations, ensuring that all crystal orientations exist to an equal degree, and preferably to introduce an appropriate amount of cube orientations.

[0058] For example, in Cu-Ni-Si alloy sheets manufactured using conventional processes, there is a tendency for the area fractions [S] of the S orientation {2 3 1}<3 46> and [BR] of the BR orientation {3 6 2}<8 5 3> to be higher. On the other hand, the area fractions [W] of the Cube orientation {10 0}<0 0 1>, [RDW] of the RDW orientation {0 1 2}<1 0 0>, and [G] of the Goss orientation {0 1 1}<10 0> are smaller. As a result, the ratio γ exceeds 3.0, and the lug ratio is positive and relatively large.

[0059] Furthermore, the larger the absolute value of the lug ratio, the lower the tensile workability of the copper alloy sheet. In particular, if the absolute value of the lug ratio is greater than 6.0%, cracks are more likely to occur from the lugs during the tensile process.

[0060] Therefore, in the copper alloy sheet of the embodiment, by increasing [W], [RDW] and [G] and controlling the ratio γ within the above range, the generation of lugs can be suppressed, thereby obtaining excellent tensile workability of the copper alloy sheet.

[0061] If the ratio γ is 1.4 or higher and 3.0 or lower, the lugs are small, making it easier to achieve uniform stretching. If the ratio γ is less than 1.4, the 0° lugs are very large, thus significantly reducing the stretching workability of the copper alloy sheet. In particular, if the ratio γ is less than 1.4, excessive cube orientations that negatively affect stretching workability will form, leading to frequent breakage during stretching. Furthermore, if the ratio γ is greater than 3.0, the 45° lugs are very large, further significantly reducing the stretching workability of the copper alloy sheet. From this perspective, the lower limit for the ratio γ is 1.4 or higher, preferably 1.5 or higher, and the upper limit is 3.0 or lower, preferably 2.1 or lower.

[0062] Furthermore, if the area ratio [W] of the Cube orientation {1 0 0}<0 0 1> is 5.0% or more and 20.0% or less, the material anisotropy of the copper alloy sheet is reduced, and the excellent bending workability of the copper alloy sheet can be utilized. If [W] is less than 5.0%, the bending workability of the copper alloy sheet is insufficient. On the other hand, an excessive number of Cube orientations will significantly reduce the tensile workability of the copper alloy sheet. If [W] is greater than 20.0%, the material anisotropy of the copper alloy sheet becomes high, therefore, the lugs become larger, the tensile workability of the copper alloy sheet decreases, and depending on the situation, it is prone to breakage during tensile processing. From this point of view, the lower limit value of [W] is 5.0% or more, preferably 10.0% or more, and the upper limit value is 20.0% or less, preferably 18.0% or less.

[0063] The area ratio of each crystal orientation can be obtained from the crystal orientation resolution data calculated using analytical software (TSL, OIM Analysis) based on the 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. The EBSD method is a crystal orientation resolution technique that utilizes the reflected electrons diffracting Kikuchi lines generated when a copper alloy plate used as the test sample is irradiated with an electron beam within a scanning electron microscope (SEM). "OIM Analysis" is the analytical software used to analyze the data measured using EBSD.

[0064] The measurement area is obtained by mirror finishing the surface (main surface) of the copper alloy sheet using electrolytic grinding, or by mirror finishing a cross-section parallel to the rolling direction of the copper alloy sheet using electrolytic grinding and polishing (colloidal silica). To ensure the quantitative accuracy of the measurements over a wide range, it is preferable to measure the surface of the copper alloy sheet. When measuring the cross-section of the copper alloy sheet, measurements are taken from at least three fields of view, and the average value is calculated. The measurement area is set to 1000 μm × 1000 μm (1,000,000 μm). 2 The scanning step size was set to 0.2 μm for measurement. For atomic planes of grains with a deviation angle of less than 10° from each ideal orientation, the area of ​​atomic planes in each orientation can be calculated, and the area ratio of each orientation can be obtained by dividing the total measured area by the aforementioned area.

[0065] Furthermore, regarding stretching, it is generally known that larger grain size improves stretching workability. On the other hand, regarding bending, large grain size may lead to increased cracks or wrinkles in the bent portion. Therefore, the average grain size in the cross-section perpendicular to the rolling direction of the copper alloy sheet is preferably 30 μm or less, more preferably 25 μm or less. Moreover, if the grain size is too fine, the area fraction [W] of {1 0 0}<0 0 1> in the cube orientation may decrease. Therefore, the average grain size in the cross-section perpendicular to the rolling direction of the copper alloy sheet is preferably 5 μm or more.

[0066] The copper alloy sheet described in this embodiment, due to its excellent tensile and bending workability, is suitable as both a copper alloy sheet for bending and a copper alloy sheet for drawing. Bent products obtained by bending a copper alloy sheet used as a pre-bending material (i.e., bent products using copper alloy sheets), or drawn products obtained by drawing a copper alloy sheet used as a pre-drawing material (i.e., drawn products using copper alloy sheets), are preferably used in connectors, lead frames, relays, switches, sockets, shielding boxes, shielding cans, camera module housings, vibration device housings, heat dissipation parts for liquid crystal or organic EL displays, batteries, gas shielding valves, etc., for electronic devices or automotive applications.

[0067] Next, the manufacturing method of the copper alloy sheet according to the above embodiment will be described. The ingot with the above alloy composition obtained by melting and casting [step 1] is subjected to reheating [step 2], hot rolling [step 3], intermediate annealing [step 4], first cold rolling [step 5], solution heat treatment [step 6], second cold rolling [step 7], aging heat treatment [step 8], third cold rolling [step 9], and low temperature annealing [step 10] to manufacture the copper alloy sheet according to the above embodiment.

[0068] In the melting and casting [step 1], the alloy components are melted and cast to obtain a copper alloy ingot with the aforementioned alloy composition. For example, melting is carried out in an atmospheric environment using a high-frequency melting furnace. The type of alloy composition, casting conditions, etc., can be appropriately set.

[0069] In the reheating process [Process 2] following the melting and casting [Process 1], the copper alloy ingot is heat-treated and homogenized by holding it at a specific temperature for a specific time in a reheat furnace. In the reheating process [Process 2], the copper alloy ingot is heat-treated for 1 to 10 hours within a temperature range of 900°C to 1050°C. If the heat treatment temperature is below 900°C, it is prone to becoming an inhomogeneous structure during hot rolling [Process 3], and dynamic recrystallization will not occur sufficiently. If the heat treatment temperature exceeds 1050°C, the grain boundaries weaken, and cracks are prone to occur during hot rolling [Process 3].

[0070] Hot rolling [Process 3] is performed immediately after reheating [Process 2]. Hot rolling [Process 3] can be performed under conditions accompanied by dynamic recrystallization. For example, hot rolling is performed with a processing rate of 50% or more, calculated based on the thickness before rolling begins and the thickness after the passes completed before reaching 700°C during the period from reheat temperature to 700°C. When dynamic recrystallization is not sufficiently generated, an inhomogeneous structure is easily formed. The material temperature during hot rolling can be measured using a radiation thermometer. In addition, after hot rolling [Process 3], a planar cut of, for example, 1 to 5 mm can be performed depending on the oxidation state of the surface.

[0071] In the intermediate annealing [step 4] following hot rolling [step 3], a heat treatment is performed at a temperature of 400°C to 600°C for 30 seconds to 2 hours, causing Ni2Si precipitates to form. This changes the solid solution state and produces a grain pinning effect. As a result, the development of specific crystal orientations can be suppressed in both the rolled aggregate obtained by the first cold rolling [step 5] and the recrystallized aggregate obtained by the solution heat treatment [step 6]. In particular, the cube orientation, which was not developed in the previous steps, is easily developed in various crystal orientations. As a result, the material anisotropy is reduced, and the lugs during drawing are reduced. When the heat treatment temperature is below 400°C, Ni2Si precipitates of sufficient size are not formed; similarly, when the heat treatment temperature exceeds 600°C, Ni2Si precipitates of sufficient size are not formed. As a result, the cube orientation or RDW orientation is not formed after solution heat treatment, therefore, the ratio γ is greater than 3.0, and the drawing workability of the copper alloy sheet is reduced.

[0072] After intermediate annealing [step 4], the first cold rolling [step 5] is performed. The first cold rolling [step 5] is performed by adjusting the processing rate within the range of 70.0% to 99.9% according to the thickness of the copper alloy sheet of the final product.

[0073] In the solution heat treatment [step 6] following the first cold rolling [step 5], the temperature is held at 750°C to 1000°C for 10 to 60 seconds, followed by cooling. Through intermediate annealing [step 4], the cube orientation or other orientations are developed in this step, suppressing agglomeration towards specific crystal orientations. When the solution heat treatment temperature is less than 750°C and / or the holding time is less than 10 seconds, the cube orientation is not sufficiently developed, reducing the bending workability of the copper alloy sheet. When the solution heat treatment temperature exceeds 1000°C, the cube orientation is excessive, and the crystal grain size becomes coarse, thus reducing the tensile and bending workability of the copper alloy sheet. When the holding time exceeds 60 seconds, the crystal grain size becomes coarse, thus reducing the bending workability of the copper alloy sheet.

[0074] In the second cold rolling [step 7] following the solution heat treatment [step 6], a cold rolling rate of 10% to 30% is performed. After the solution heat treatment [step 6], various crystal orientations are formed, but the material anisotropy remains high, resulting in a higher lug ratio after stretching. The main reason is that after solution treatment, not only the area ratio of the Cube orientation increases, but also the area ratio of the RDW orientation increases. Therefore, by implementing this step, the Copper orientation or S orientation, which are the main rolling aggregate structures, are appropriately formed, thereby significantly suppressing the material anisotropy and reducing the lug ratio. As a result, the excessive formation of RDW or Goss orientations during solution heat treatment can be reduced. On the other hand, in the Cube orientation, since the crystal orientation is symmetrical with respect to the sheet metal, crystallization rotation caused by rolling is less likely to occur, thus retaining the Cube orientation which is beneficial to bending workability. Furthermore, in this process, the grains coarsened during solution heat treatment [process 6] become finer, thus improving bending workability. When the processing rate is less than 10%, the changes in crystal orientation or grain size are small. When the processing rate exceeds 30%, the strong rolled aggregate structure develops again, thus increasing the material anisotropy and worsening the lug ratio.

[0075] In the aging heat treatment [step 8] following the second cold rolling [step 7], the temperature is maintained at 400°C to 600°C for 1 hour to 10 hours. If the temperature does not reach 400°C and / or the holding time is less than 1 hour, precipitation strengthening cannot be obtained, resulting in reduced material strength and conductivity. If the temperature exceeds 600°C and / or the holding time exceeds 10 hours, the precipitates become coarse and precipitation strengthening cannot be obtained, resulting in reduced material strength.

[0076] In the third cold rolling process [step 9] following the aging heat treatment [step 8], a cold rolling process with a processing rate of 5% to 20% is performed. When the processing rate is less than 5%, the effect of increasing the material strength is relatively small. When the processing rate exceeds 40%, the rolled aggregate structure in the Brass orientation, S orientation, etc., tends to develop, and the anisotropy tends to increase, thus reducing the tensile workability of the copper alloy sheet.

[0077] In the low-temperature annealing [process 10] performed after the third cold rolling [process 9], the temperature is maintained at 200°C to 600°C for 10 seconds to 30 minutes.

[0078] According to the embodiments described above, by having a specific alloy composition and controlling the ratio γ of the area ratio of each crystal orientation and the area ratio [W] of the Cube orientation {1 0 0}<0 0 1> within a specific range, copper alloy sheets can achieve both excellent tensile workability and bending workability.

[0079] The embodiments have been described above, but the present invention is not limited to the above embodiments, but includes all the forms contained in the concepts of this disclosure and the scope of the claims, and various changes can be made within the scope of this disclosure.

[0080] [Example]

[0081] Next, embodiments and comparative examples will be described, but this disclosure is not limited to these embodiments.

[0082] (Examples 1-24 and Comparative Examples 1-11)

[0083] In the melting and casting [step 1], the components are melted in an atmospheric environment using a high-frequency melting furnace, and then cast using a metal mold to obtain a copper alloy ingot with the copper alloy composition shown in Table 1. Subsequently, the copper alloy ingot is subjected to heat treatment at a temperature of 900°C to 1050°C for a period of 1 to 10 hours in sequence: reheating [step 2], hot rolling with dynamic recrystallization immediately after reheating [step 2], intermediate annealing under the conditions shown in Table 2 [step 4], first cold rolling with a processing rate of 70.0% to 99.9% [step 5], solution heat treatment under the conditions shown in Table 2 [step 6], second cold rolling [step 7], aging heat treatment [step 8], third cold rolling [step 9], and low-temperature annealing [step 10] to obtain a copper alloy plate with a thickness of 0.05 mm to 0.50 mm.

[0084] [Table 1]

[0085]

[0086] [Table 2]

[0087]

[0088] [Measurement and Evaluation]

[0089] The copper alloy plates obtained in the above embodiments and comparative examples were subjected to the following measurements and evaluations. The results are shown in Table 3.

[0090] [1] The ratio of the area ratio of the crystal orientation γ

[0091] The area ratio of each crystal orientation was obtained by calculating the crystal orientation resolution data using analytical software (TSL, OIM Analysis) based on the crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (manufactured by JEOL Ltd., JSM-7001FA). The measurement area was set as the surface (main surface) of the copper alloy plate obtained by mirror finishing through electrolytic polishing, and the measurement area was set as 1000 μm × 1000 μm (1,000,000 μm). 2 The scanning step size was set to 0.2 μm for measurement. For the atomic planes of grains with a deviation angle of less than 10° from each ideal orientation, the area of ​​the atomic planes in each orientation was calculated, and the total measured area was divided by this area to obtain the area ratio of each orientation. Furthermore, the ratio γ is calculated by dividing the sum of the area ratios [BR] of the BR orientation {3 6 2}<8 5 3>, the area ratios [C] of the Copper orientation {1 21}<1 1 1>, the area ratios [S] of the S orientation {2 3 1}<3 4 6>, and the area ratios [B] of the Brass orientation {1 1 0}<1 1 2> ([BR] + [C] + [S] + [B]) by the sum of the area ratios [W] of the Cube orientation {1 0 0}<0 0 1>, the area ratios [RDW] of the (RDW) orientation {0 1 2}<1 0 0>, and the area ratios [G] of the Goss orientation {0 1 1}<1 0 0> ([W] + [RDW] + [G]).

[0092] [2] Average crystal grain size

[0093] After the cross-section perpendicular to the rolling direction of the copper alloy sheet is finished to a mirror surface using wet grinding and polishing, the ground surface is etched for several seconds using a weak acid solution. The surface obtained by etching the ground surface is photographed at 200-500x magnification using an optical microscope (OM), and the grain size in the image is measured using the cutting method specified in Japanese JIS (JIS H0501). The average grain size is calculated by averaging these grain sizes.

[0094] [3] Tensile workability

[0095] A 0.2 mm thick copper alloy sheet was subjected to a single cylindrical drawing process, and the lug ratio of the drawn product was measured. During the process, a 40 mm diameter blank was formed by stamping, and then drawn using a 20 mm diameter punch. The punch shoulder radius was 1 mm. Furthermore, the surface of the blank was coated with lubricating oil (R303P) before processing. Then, the workability was rated according to the following criteria.

[0096] ◎: The rate of protruding ears is between -3.0% and 3.0%.

[0097] 〇: The bulging ear rate is above -6.0% but below -3.0%, or above 3.0% but below 6.0%.

[0098] ×: Cracks occurred during stretching, or the lug rate was less than -6.0% or exceeded 6.0%.

[0099] [4] Bending workability

[0100] BW (Bad-way) bending was performed on copper alloy sheets with a width of 10 mm and a length of 25 mm, bending them along the rolling direction. During bending, a 90° bending die with a 0.4 mmR radius was used for pre-bending, followed by a 180° close-fitting bend using a compression testing machine. Then, the outer side of the bent portion was observed for cracks using an optical microscope, and the degree of wrinkling was visually assessed. Workability was judged based on the Japanese Copper Industry Association technical standard "JCBA T307:2007 Evaluation Method for Workability of Copper and Copper Alloy Sheets," with evaluation criteria A or B set as "◎", evaluation criterion C set as "〇", and the occurrence of cracks set as "×".

[0101] [Table 3]

[0102]

[0103] Figure 3 is a graph showing the relationship between the ratio γ and the lug ratio for embodiments and comparative examples that can be stretched without cracking. As shown in Tables 1-3, in Examples 1-24, specific alloy compositions are used, and the ratio γ and the area ratio [W] of the cube orientation {1 0 0}<0 0 1> are controlled within specific ranges. Therefore, both stretch workability and bending workability are excellent. On the other hand, in Comparative Examples 1-11, at least one of the alloy composition, ratio γ, and [W] is outside the specific range. Therefore, at least one of the stretch workability and bending workability is poor.

[0104] Specifically, in Example 2, since the temperature of the solution heat treatment [step 6] is lower than that in Example 1, the area ratio of the cube orientation is smaller, the ratio γ is larger, and the absolute value of the lug ratio is larger compared to Example 1. In Example 3, since the temperature of the solution heat treatment [step 6] is higher than that in Example 1, the area ratio of the cube orientation is larger, the ratio γ is smaller, and the lug ratio is increased compared to Example 1. Compared to Example 1, the average crystal grain size is coarser, and the wrinkles are larger, but due to the higher area ratio of the cube orientation, no bending cracks are observed. In Example 4, since the temperature of the intermediate annealing [step 4] is higher than that in Example 1, the area ratio of the cube orientation is larger, the γ is smaller, and the lug ratio is increased compared to Example 1. In Example 5, since the temperature of the intermediate annealing [step 4] is further increased compared to Example 4, the area ratio of the cube orientation is further increased, the γ is further decreased, and the lug ratio is further increased. In Example 6, because the intermediate annealing [step 4] processing time is longer than in Example 1, the area ratio of the Cube orientation is larger, γ is smaller, and the lug ratio is increased compared to Example 1. In Example 7, because the intermediate annealing [step 4] processing time is longer than in Example 5, the area ratio of the Cube orientation is smaller, γ is smaller, and the absolute value of the lug ratio is slightly increased compared to Example 5. In Examples 8 to 14, the processing rate of the second cold rolling [step 7] in Examples 1 to 7 is increased, and it is observed that the area ratio of the Cube orientation tends to be the same or smaller, while the area ratios of the BR and S orientations increase. Therefore, compared to Examples 1 to 7, the ratio γ is larger, and the average crystal grain size becomes finer. In Examples 15 to 23, the Ni content, Si content, and arbitrary component content are different from those in Examples 1 to 14, but since they are within a specific range, the tensile workability and bending workability are excellent. In Example 24, although the content of any component was not within the preferred range, the tensile and bending workability was superior compared to Comparative Examples 1-11.

[0105] In Comparative Examples 1 and 2, the temperature of the intermediate annealing [step 4] was outside a specific range, and the effect of intermediate annealing was almost negligible. Therefore, the area ratios of the BR and S orientations were higher, the ratio γ was larger, and the lug ratio deteriorated. In Comparative Example 3, due to the lower temperature of the solution heat treatment [step 6], the area ratios of the Cube, RDW, and Goss orientations were lower, the ratio γ was larger, the lug ratio deteriorated, and the bending workability also deteriorated. In Comparative Example 4, due to the higher temperature of the solution heat treatment [step 6], the area ratio of the Cube orientation was higher, resulting in fracture during stretching. Furthermore, although the average grain size was large, the area ratio of the Cube orientation was higher, so no bending cracks were observed. In Comparative Example 5, due to the lower processing rate of the cold working [step 7], the area ratio of the Cube orientation was higher, resulting in fracture during stretching. Furthermore, although the average grain size was large, the area ratio of the Cube orientation was higher, so no bending cracks were observed. In Comparative Example 6, due to the high processing rate of cold working [step 7], the area ratio of the cube orientation was low, the ratio γ was large, the lug ratio deteriorated, and the bending workability also deteriorated. In Comparative Example 7, due to the high Ni content, the elongation was reduced, and it broke during stretching. In Comparative Example 8, due to the low Ni content, the area ratio of the cube orientation was high, and it broke during stretching. In Comparative Example 9, due to the low Si content, the area ratio of the cube orientation was high, the ratio γ was small, and the lug ratio deteriorated. In Comparative Example 10, the high Si content reduced the elongation, and it broke during stretching. Due to the low cube orientation, the bending workability also deteriorated. In Comparative Example 11, due to the low Ni and Si contents, the area ratio of the cube orientation was high, it broke during stretching, and the average crystal grain size was large, and the bending workability also deteriorated.

Claims

1. A copper alloy plate having the following alloy composition: containing 1.00% by mass and 5.00% by mass of Ni and 0.20% by mass and 1.50% by mass of Si, with the remainder being Cu and unavoidable impurities; When the area ratio of the BR orientation {3 6 2}<8 5 3> determined by the EBSD method is set as [BR], the area ratio of the Copper orientation {1 21}<1 1 1> is set as [C], the area ratio of the S orientation {2 3 1}<3 4 6> is set as [S], the area ratio of the Brass orientation {1 10}<1 1 2> is set as [B], the area ratio of the Cube orientation {1 0 0}<0 0 1> is set as [W], the area ratio of the RD-Rotated-Cube orientation {0 1 2}<1 0 0> is set as [RDW], and the area ratio of the Goss orientation {0 1 1}<1 0 0> is set as [G], The ratio of the area ratio of crystal orientation, γ, i.e., ([BR]+[C]+[S]+[B]) / ([W]+[RDW]+[G]), is between 1.4 and 3.

0. [W] is between 5.0% and 20.0%.

2. The copper alloy sheet according to claim 1, wherein, The average grain size in the cross-section perpendicular to the rolling direction of the aforementioned copper alloy sheet is less than 30 μm.

3. The copper alloy sheet according to claim 1, wherein, The aforementioned alloy composition It further contains one or more elements selected from the group consisting of Sn, Zn, Mg, Fe and Cr, in a total of more than 0.05% by mass and less than 1.00% by mass.

4. A bent product using a copper alloy sheet according to any one of claims 1 to 3.

5. A stretched article using a copper alloy sheet according to any one of claims 1 to 3.

Images