TW202340488A - Copper alloy sheet material and method for manufacturing same - Google Patents

Abstract

Provided are: a copper alloy sheet material with high tensile strength and a small temperature coefficient of resistance (TCR), thereby making it possible to increase the reliability of products to which said sheet material is applied, such as connectors and lead frames; and a method for manufacturing the copper alloy sheet material. The copper alloy sheet material has an alloy composition in which at least one component among Ni and Co is in a total of 0.50 mass% or more and 5.00 mass% or less, Si is contained in a range of 0.10 mass% or more and 1.50 mass% or less, and the remainder is Cu and unavoidable impurities. The area ratio of crystal grains for a measured GROD value range of 0 DEG or more and 5 DEG or less when the GROD value was measured using EBSD in a cross-section including the rolling direction and the thickness direction of the copper alloy sheet material is in the range of 20% or more and 82% or less. The tensile strength is 500 MPa or more and the temperature coefficient of resistance (TCR) in a temperature range of from 20 DEG C to 150 DEG C is 3000 ppm/DEG C or less.

Description

Copper alloy plate and manufacturing method thereof

The present invention relates to a copper alloy plate and its manufacturing method, particularly to a copper alloy plate that can be used in applied products, such as connectors and lead frames, relays, switches, etc. for electrical and electronic machines, and its manufacturing method.

Metal materials used in connectors, lead frames, relays, switches, etc., have a resistance value that does not change significantly from room temperature even in an environment with a higher operating temperature than room temperature. High tensile strength can improve reliability, so it is required to have a small temperature coefficient of resistance (TCR, Temperature Coefficient of Resistivity) and high tensile strength. The temperature coefficient of resistance is an indicator of the stability of the resistance when the ambient temperature changes. .

Here, the temperature coefficient of resistance (TCR) is a numerical value that expresses the degree of change in resistance value due to temperature in parts per million (ppm) per 1°C, and can be expressed by the following formula: TCR (×10 ^-6 / ℃)={(R－R ₀ )/R ₀ }×{1/(T－T ₀ )}×10 ⁶ . In the formula, T represents the test temperature (℃), T ₀ represents the reference temperature (℃), R represents the resistance value (Ω) at the test temperature T, and R ₀ represents the resistance value (Ω) at the reference temperature T ₀ . In particular, Cu-Mn-Ni alloy and Cu-Mn-Sn alloy are widely used as alloy materials with very small TCR.

For example, Patent Document 1 describes a Cu-Mn-Ni alloy used for chip resistors, and also describes a copper alloy containing Mn in the range of 21.0 mass % or more and 30.2 mass % or less and 8.2 mass % In a copper alloy containing Ni in the range of % or more and 11.0% by mass or less, the TCR value x [ppm/℃] in the temperature range from 20°C to 60°C is set to -10≦x≦-2 or 2 ≦x≦10, and the volume resistivity ρ is set to 80×10 ^-8 [Ω・m] or more and 115×10 ^-8 [Ω・m] or less. The copper alloy of Patent Document 1 is considered to be able to suppress the Joule heat of the resistive material from increasing by controlling the magnitude of the temperature coefficient of resistance (TCR).

On the other hand, Corson Copper Alloy (Cu-Ni-Si alloy) is known as a copper alloy used in connectors and lead frames for electrical and electronic equipment.

For example, Patent Document 2 discloses a Cu-Ni-Si alloy with excellent bending workability and stress relaxation properties, which contains 1.0 to 4.5 mass % Ni and 0.2 to 1.0 mass % Si, and the balance is composed of copper and insoluble materials. It is composed of avoidable impurities, and relative to the number of crystal grains per unit area in the rolling parallel section, the proportion of the number of crystal grains with a crystal diameter of less than 10 μm is more than 15%, and the proportion of the number of crystal grains with a diameter of more than 20 μm is The proportion is more than 15%. The copper alloy of Patent Document 2 is considered to be able to improve stress relaxation characteristics by controlling the crystal diameter of the Cu-Ni-Si alloy. [Prior technical literature] (patent document)

Patent Document 1: Japanese Patent Application Publication No. 2017-53015. Patent Document 2: Japanese Patent Application Publication No. 2013-95977.

[Problem to be solved by the invention] However, the copper alloy of Patent Document 1 has a volume resistivity ρ of 80×10 ^-8 [Ω・m] or more and 115×10 ^-8 [Ω・m] or less, and uses Chip resistors have a small volume resistivity, but the volume resistivity of the copper alloy is not low enough to sufficiently suppress Joule heat generation. Therefore, there are applications such as connectors, lead frames, relays, switches, etc. Parts through which high current density flows may not be usable unless there are very limited conditions such as low energization and no influence of heat generation.

In addition, the copper alloy disclosed in Patent Document 2 does not examine at all the stability of resistance when the ambient temperature changes, as represented by the temperature coefficient of resistance, and does not even disclose a good balance between high tensile strength and low temperature coefficient of resistance. With such content, there are no evaluation results showing these characteristics.

Therefore, the present invention is made in view of the above problems, and aims to provide a copper alloy plate and a manufacturing method thereof. The copper alloy plate has high tensile strength and a small temperature coefficient of resistance (TCR), thereby improving the performance of the connector. and the reliability of application products such as lead frames. [Technical means to solve problems]

The inventor found that in a copper alloy sheet having an alloy composition, at least by setting the area ratio of crystal grains in the range of 0° or more and 5° or less with a GROD value measured using the EBSD method to 20% or more and The temperature coefficient of resistance (TCR) of the copper alloy sheet becomes smaller in the range of 82% or less. The alloy composition contains at least one component of Ni and Co in a total of 0.50 mass% or more and 5.00 mass% or less, and 0.10 mass% or more and Si in the range of 1.50% by mass or less, and the remainder is composed of Cu and unavoidable impurities. The inventor further discovered that by setting the tensile strength of such a copper alloy plate to 500 MPa or more, a copper alloy plate with high tensile strength and a small temperature coefficient of resistance (TCR) can be obtained, and completed the present invention.

(1) A copper alloy sheet having the following alloy composition: at least one component of Ni and Co in a total amount of 0.50 mass% or more and 5.00 mass% or less, and Si in the range of 0.10 mass% or more and 1.50 mass% or less, And the remaining part is composed of Cu and unavoidable impurities. When the GROD value is measured using the EBSD method for the cross section including the rolling direction and the thickness direction of the copper alloy plate, the measured GROD value is between 0° and 5°. The area ratio of crystal grains in the following range is 20% or more and 82% or less, the tensile strength is 500 MPa or more, and the temperature coefficient of resistance (TCR) in the temperature range from 20°C to 150°C is 3000 ppm /℃ below.

(2) The copper alloy sheet as described in (1) above, wherein the alloy composition further contains a component selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr in a total range of 0.10 mass% or more and 1.00 mass% or less. At least one component of the group.

(3) A method of manufacturing a copper alloy plate, which is a method of manufacturing a copper alloy plate as described in (1) or (2) above. The method of manufacturing a copper alloy material having the same alloy composition as the aforementioned alloy composition is based on The following steps are performed in sequence: melting casting step [step 1], homogenization step [step 2], hot rolling step [step 3], plane cutting step [step 4], first cold rolling step [step 5], first heat treatment step [step 6], the second heat treatment step [step 8] and the finishing step [step 9]; in the aforementioned first heat treatment step [step 6], the heating temperature is in the range of 750°C or more and below 1000°C; the aforementioned second heat treatment step [step 6] In the heat treatment step [step 8], the heating temperature is in the range of above 450°C and below 550°C; the aforementioned finishing step [step 9] consists of more than 2 passes of finishing cold rolling [step 9-1] and The aforementioned finishing cold rolling [step 9-1] consists of finishing heat treatment [step 9-2] performed after each pass. The aforementioned finishing cold rolling [step 9-1], the partial processing rate of each pass The maximum value is in the range of 4% or more and 10% or less and the total processing rate is in the range of 10% or more and 40% or less. The aforementioned finishing heat treatment [step 9-2], the heating temperature is in the range of 300°C or more and 400°C or less. .

(4) The method for manufacturing a copper alloy sheet as described in (3) above, wherein a second cold rolling step [Step 8] is further performed between the first heat treatment step [Step 6] and the second heat treatment step [Step 8]. Step 7], in the aforementioned second cold rolling step [Step 7], the total processing rate is set in the range of 5% or more and 70% or less. [Effects of the invention]

According to the present invention, a copper alloy plate material and a manufacturing method thereof can be provided. The copper alloy plate material has high tensile strength and a small temperature coefficient of resistance (TCR), thereby improving the reliability of applied products such as connectors and lead frames.

Next, embodiments of the present invention will be described. The following description is an example showing embodiments of the present invention and is not intended to limit the patentable scope of the invention.

The copper alloy sheet according to the present invention is a copper alloy sheet having an alloy composition containing at least one component of Ni and Co in a total of 0.50 mass % or more and 5.00 mass % or less, and 0.10 mass % or more and 1.50 mass %. % or less of Si, and the remainder is composed of Cu and unavoidable impurities. When the GROD value is measured using the EBSD method on the cross section of the copper alloy sheet including the rolling direction and the thickness direction, the GROD value is measured Resistance temperature in the temperature range from 20°C to 150°C with a tensile strength of 500 MPa or more and an area ratio of crystal grains in the range of 0° to 5° from 20% to 82% Coefficient (TCR) is 3000 ppm/℃ or less.

The copper alloy sheet of the present invention preferably contains appropriate amounts of at least one component of Ni, Co and a Si component, and when the GROD value is measured using the EBSD method for a cross section including the rolling direction and the thickness direction, The area ratio of crystal grains with a measured GROD value in the range of 0° or more and 5° or less is set in the range of 20% or more and 82% or less. In particular, by setting the area ratio of crystal grains with a GROD value in the range of 0° to 5° to 20% or more, the temperature coefficient of resistance (TCR) in the temperature range from 20°C to 150°C can be improved. ) becomes smaller. In addition, by setting the area ratio of crystal grains with a GROD value in the range of 0° or more and 5° or less to 82% or less, the tensile strength, especially the tensile strength, of the copper alloy sheet can be improved. In particular, the present invention can obtain a copper alloy plate having high tensile strength and a small temperature coefficient of resistance (TCR) when the tensile strength of the copper alloy plate is 500 MPa or more. Therefore, the copper alloy plate of the present invention can provide a copper alloy plate that has high tensile strength and a small temperature coefficient of resistance (TCR) and a manufacturing method thereof. As a result, the reliability of applied products such as connectors and lead frames can be improved.

[1] Alloy composition of copper alloy plates The alloy composition of the copper alloy plate material of the present invention contains, as essential components, at least one component of Ni and Co in a total amount of 0.50 mass % or more and 5.00 mass % or less, and a range of 0.10 mass % or more and 1.50 mass % or less. Si. The following explains the reasons for limiting the alloy composition of the copper alloy plate material.

(Ni and Co: the total of at least one component is 0.50 mass% or more and 5.00 mass% or less) Ni (nickel) and Co (cobalt) are both important components that can increase the tensile strength of copper alloy sheets. Here, if the total content of Ni and Co is less than 0.50% by mass, the tensile strength of the copper alloy sheet will decrease and the temperature coefficient of resistance (TCR) will also increase. In addition, if the total content of Ni and Co exceeds 5.00% by mass, rough crystallization will be easily generated in the ingot, so that after the first heat treatment step [Step 6] described below, the crystallization will still be The undissolved state remains, so it can easily become the starting point of cracks when mechanical processing such as bending is performed on the copper alloy plate. Furthermore, if the total content of Ni and Co exceeds 5.00% by mass, the material cost of the copper alloy plate will tend to increase. Therefore, it is necessary to add one or two components of Ni and Co, and contain these components in a range of 0.50 mass % or more and 5.00 mass % or less in total. In particular, the total content of Ni and Co is preferably in the range of 1.50 mass% or more and 5.00 mass% or less, and more preferably in the range of 2.50 mass% or more and 5.00 mass% or less.

(Si: 0.10 mass% or more and 1.50 mass% or less) Si (silicon) is an important component that can improve the tensile strength of copper alloy sheets. From the viewpoint of exerting this effect, the Si content needs to be 0.10 mass % or more. On the other hand, if the Si content exceeds 1.50% by mass, rough crystallization will easily occur in the ingot. Therefore, after the first heat treatment step [Step 6] described below, the crystallization will still be unsolidified. The molten metal remains in a molten state, so it can easily become the starting point of cracks when mechanical processing such as bending is performed on the copper alloy plate. Therefore, Si needs to be contained in the range of 0.10 mass% or more and 1.50 mass% or less. In particular, the Si content is preferably in the range of 0.20 mass% or more and 1.40 mass% or less, and more preferably in the range of 0.30 mass% or more and 1.30 mass% or less.

＜Any additional ingredients＞ Furthermore, the copper alloy sheet of the present invention may contain at least one component selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr as an optional component in a total range of 0.10 mass % or more and 1.00 mass % or less. Add ingredients.

(Mg: 0.10 mass% or more and 0.30 mass% or less) Mg (magnesium) is a component that has the effect of improving stress relaxation properties. In order to exert this effect, the Mg content is preferably 0.10% by mass or more. On the other hand, if the Mg content exceeds 0.30% by mass, the conductivity tends to decrease. Therefore, the Mg content is preferably in the range of 0.10 mass% or more and 0.30 mass% or less.

(Sn: 0.10 mass% or more and 0.30 mass% or less) Sn (tin) is a component that improves stress relaxation properties. In order to exert this effect, the Sn content is preferably 0.10% by mass or more. On the other hand, if the Sn content exceeds 0.30% by mass, the electrical conductivity tends to decrease. Therefore, the Sn content is preferably in the range of 0.10 mass% or more and 0.30 mass% or less.

(Zn: 0.10 mass% or more and 0.50 mass% or less) Zn (zinc) is a component that improves the adhesion and migration characteristics of Sn plating. In order to exert this effect, the Zn content is preferably 0.10% by mass or more. On the other hand, if the Zn content exceeds 0.50% by mass, the electrical conductivity tends to decrease. Therefore, the Zn content is preferably in the range of 0.10 mass% or more and 0.50 mass% or less.

(P: 0.10 mass% or more and 0.30 mass% or less) P (phosphorus) is a component that suppresses the precipitation of Si compounds at grain boundaries and improves the tensile strength of copper alloy sheets. In order to exert this effect, it is preferable to set the P content to 0.10 mass % or more. On the other hand, if the P content exceeds 0.30% by mass, the electrical conductivity tends to decrease. Therefore, the P content is preferably in the range of 0.10 mass% or more and 0.30 mass% or less.

(Cr: 0.10 mass% or more and 0.30 mass% or less) Cr (chromium) is a component that has the effect of suppressing the roughening of crystal grains during melt heat treatment. To achieve this effect, the Cr content is preferably 0.10% by mass or more. On the other hand, if the Cr content exceeds 0.30% by mass, rough crystallization containing Cr will be easily generated during casting, and therefore the starting point of cracks will be easily formed. Therefore, the Cr content is preferably in the range of 0.10 mass% or more and 0.30 mass% or less.

(Zr: 0.10 mass% or more and 0.20 mass% or less) Zr (zirconium) is a component that has the effect of suppressing the roughening of crystal grains during melt heat treatment. In order to exert this effect, it is preferable to set the Zr content to 0.10 mass % or more. On the other hand, if the Zr content exceeds 0.20 mass %, rough crystallization products containing Zr are likely to be generated during casting, thereby easily forming the starting point of cracks. Therefore, the content of Zr is preferably in the range of 0.10 mass% or more and 0.20 mass% or less.

(Total content of optionally added ingredients: 0.10 mass% or more and 1.00 mass% or less) Since these optionally added components can obtain the effects produced by the above-mentioned optionally added components, it is preferable that the total content is 0.10% by mass or more. On the other hand, if these optional additive components are contained in large amounts, compounds are likely to be generated between the optionally added components and the essential components, so the total amount is preferably 1.00 mass % or less.

(Remainder: Cu and unavoidable impurities) The copper alloy constituting the copper alloy plate material has an alloy composition in which, in addition to the above-mentioned components, the remainder is Cu (copper) and unavoidable impurities. Furthermore, the "inevitable impurities" referred to here are allowable impurities, which are components present in raw materials in most metal products or components that are unavoidably mixed in during the manufacturing process and are not originally intended. A necessary component, but it is acceptable in trace amounts and will not affect the properties of metal products. Examples of components that can be cited as unavoidable impurities include non-metallic elements such as S (sulfur), C (carbon), and O (oxygen), and metallic elements such as Sb (antimony). Furthermore, the upper limit of the content of these components can be, for example, 0.05% by mass for each of the above components, or 0.20% by mass based on the total amount of the above components.

[2] GROD value and area ratio of copper alloy plates The GROD (Grain Reference Orientation Deviation) value is a value obtained based on the crystal orientation analysis data of the EBSD method, and is a value that shows the misorientation within the same grain relative to the reference point. Here, the reference point is a measurement point at which the KAM value is the smallest within the crystal grain. In addition, the KAM (Kernel Average Misorientation) value is the average value of crystal misorientation between a measurement point and all measurement points adjacent to the measurement point.

For the copper alloy sheet of the present invention, when the GROD value is measured using the EBSD method on a cross-section of the copper alloy sheet including the rolling direction and the thickness direction, the measured area of the grains has a GROD value in the range of 0° or more and 5° or less. The proportion ranges from 20% to 82%. Thereby, the dislocation of the copper alloy plate material can be sufficiently stabilized, and therefore the temperature coefficient of resistance (TCR) can be reduced. Here, if the area ratio is less than 20%, the temperature coefficient of resistance (TCR) becomes large. In addition, if the area ratio is greater than 82%, the tensile strength of the copper alloy plate will be reduced. Therefore, the area ratio of crystal grains with a GROD value in the range of 0° to 5° needs to be in the range of 20% to 82%. In particular, the area ratio of crystal grains with a GROD value in the range of 0° or more and 5° or less is preferably in the range of 30% or more and 70% or less, and more preferably in the range of 40% or more and 60% or less. Scope.

The GROD value can be obtained from crystal orientation analysis data, which is continuously measured using an EBSD detector attached to a high-resolution scanning analytical electron microscope (JSM-7001FA, manufactured by JEOL Ltd.) The crystal orientation data is then calculated using analysis software (OIM Analysis, manufactured by TSL Corporation). Here, the so-called "EBSD" is the abbreviation of Electron BackScatter Diffraction (Electron Backscatter Diffraction). It is a crystal orientation analysis technology that uses reflected electron Kikuchi line diffraction. This reflected electron Kikuchi line diffraction is a scanning type. It is produced when electron rays are irradiated on the sample in an electron microscope (SEM). In addition, the so-called "OIM Analysis" is software that analyzes the data measured by EBSD. The measurement was performed in a field of view of approximately 400 μm × 800 μm, with the distance between measurement points (hereinafter also referred to as step size) being 0.5 μm. The measurement area can be performed on the cross section along the rolling direction, which is obtained by embedding the copper alloy plate in resin and then finishing it by mechanical grinding and polishing (silica gel). Here, when the plate thickness is less than 800 μm, the measurement range along the rolling direction may be increased so that the measurement surface becomes the same size as 400 μm × 800 μm. Here, measurement points with a reliability index CI value of 0.1 or more are set as analysis targets.

Furthermore, a boundary with a misalignment of 15° or more is defined as a grain boundary. When the outline of a crystal grain is drawn based on this grain boundary, the measurement point with the smallest KAM value in the same crystal grain is used as a reference point, and the analysis is performed By determining the misdirection relative to the reference point in each crystal grain for all measurement points of the target, the GROD value of each measurement point set as the target of analysis can be determined. At this time, from the ratio of the number of measurement points with a GROD value in the range of 0° to 5° relative to the total number of measurement points for which the GROD value has been determined, it is possible to determine the GROD value in the range of 0° to 5°. The area ratio of the range of grains.

[3] Tensile strength of copper alloy sheets The copper alloy sheet of the present invention must have a tensile strength of 500 MPa or more when stretched in a direction parallel to the rolling direction. In this way, even when the copper alloy sheet is used in application products such as connectors, lead frames, relays, switches, etc., the desired tensile strength can still be obtained, thereby improving the reliability of the copper alloy sheet in these applications.

Here, the tensile strength is measured on two test pieces, and the average value of the tensile strengths obtained from the two test pieces when stretched in the longitudinal direction is regarded as the measured value of the tensile strength. , the test piece was cut with the direction parallel to the rolling direction being the length direction, and was No. 13B specified in Japanese Industrial Standard JIS Z2241:2011.

[4] Temperature coefficient of resistance (TCR) of copper alloy sheets The copper alloy sheet material of the present invention must have a temperature coefficient of resistance (TCR) of 3000 ppm/°C or less in the temperature range from 20°C to 150°C. As a result, the temperature coefficient of resistance in a wide temperature range from normal temperature (for example, 20°C) to high temperature (for example, 150°C) can be reduced, so that the copper alloy sheet will have the properties of both normal temperature and service temperature. The same level of resistance can improve the reliability of copper alloy sheets used in connectors, lead frames, relays, switches, etc.

Here, the temperature coefficient of resistance (TCR) represents the change in resistance value due to temperature in parts per million per 1°C. The temperature coefficient of resistance (TCR) can be measured by using the four-terminal method according to the method specified in the Japanese Industrial Standard JIS C2526 to determine the resistance value R _{150 ℃} [mΩ] at 150°C and the resistance value at 20°C The resistance value R _{20 ℃} [mΩ], and then from the values of R _{150 ℃} and R _{20 ℃} , use TCR = {(R _{150 ℃} [mΩ]-R _{20 ℃} [mΩ])/R _{20 ℃} [mΩ] }×{1/(150[℃]-20[℃])}×10 ⁶ formula to calculate the temperature coefficient of resistance (ppm/℃). Here, R _{150 ℃} and R _{20 ℃} can be obtained by cutting a copper alloy plate into a width of 10 mm and a length of 300 mm to make a test material, setting the distance between voltage terminals to 200 mm, and The measurement current was set to 100 mA, and the voltage when the temperature of the test material was set to 20°C and 150°C was measured using the four-terminal method in accordance with the method specified in Japanese Industrial Standard JIS C2526.

[5] An example of a method of manufacturing a copper alloy plate The above-mentioned copper alloy plate can be realized by combining and controlling the alloy composition and the manufacturing process, and the manufacturing process is not particularly limited. Among them, the following method can be cited as an example of a manufacturing process capable of obtaining a copper alloy plate material that has high tensile strength and has a small temperature coefficient of resistance (TCR).

An example of the manufacturing method of the copper alloy plate material of the present invention is to perform at least the following steps in sequence on a copper alloy material having an alloy composition similar to that of the above-mentioned copper alloy plate material: a melting casting step [step 1], a homogenization step Chemicalization step [Step 2], hot rolling step [Step 3], plane cutting step [Step 4], first cold rolling step [Step 5], first heat treatment step [Step 6], second heat treatment step [Step 8] and finishing steps [Step 9]. In the first heat treatment step [step 6], the heating temperature is set to a range of 750°C or more and 1000°C or less. In addition, in the second heat treatment step [step 8], the heating temperature is set in the range of 450°C or more and 550°C or less. In addition, the finishing step [Step 9] consists of two or more passes of finish cold rolling [Step 9-1] and finishing heat treatment [Step 9] performed after each pass of finish cold rolling [Step 9-1]. -2] composed of. Among them, in the finishing cold rolling [step 9-1], the maximum value of the partial processing rate of each pass is set in the range of 4% or more and 10% or less, and the total processing rate is set in the range of 10% or more and 40% or less. In addition, in the finishing heat treatment [step 9-2], the heating temperature is set in the range of 300°C or more and 400°C or less.

(i) Melting casting step [Step 1] The melt casting step [Step 1] is a step of melting a copper alloy material having the same alloy composition as the above-mentioned alloy composition and then casting it into a specific shape (for example, 30 mm thick, 100 mm wide , length 150 mm) ingot (ingot). The melting and casting step [step 1] is preferably: for example, using a high-frequency melting furnace to melt and cast the copper alloy material in the atmosphere, an inert gas atmosphere, or a vacuum. Furthermore, the alloy composition of the copper alloy material may not be completely consistent with the alloy composition of the copper alloy plate being produced due to the adhesion or volatilization of additive components in the melting furnace during each manufacturing step. However, it is still It has an alloy composition substantially the same as that of the copper alloy plate material.

(ii) Homogenization step [Step 2] The homogenization step [Step 2] is a step of heat-treating the ingot after the melting and casting step [Step 1]. The conditions of the heat treatment in the homogenization step [step 2] are not particularly limited as long as they are generally implemented conditions. As an example of the heat treatment conditions here, the heating temperature is in the range of 850°C to 1000°C and the heating time is in the range of 1 hour to 6 hours.

(iii) Hot rolling step [Step 3] The hot rolling step [step 3] is a step of hot rolling the ingot after the homogenization step [step 2] until it reaches a predetermined thickness to produce a hot-rolled material. In the hot rolling step [Step 3], for example, it is preferable to set the rolling temperature to 700° C. or higher and the total processing rate (total reduction rate) to 50% or higher.

Here, [processing rate] (reduction rate) is the cross-sectional area before rolling minus the cross-sectional area after rolling, divided by the cross-sectional area before rolling, multiplied by 100, and expressed as a percentage. , and can be expressed by the following formula. [Processing rate]={([cross-sectional area before rolling]-[cross-sectional area after rolling])/[cross-sectional area before rolling]×100(%)

The hot rolled material after the hot rolling step [Step 3] is preferably cooled. Here, the means for cooling the hot-rolled material is not particularly limited. However, from the viewpoint that roughening of crystal grains can be made less likely to occur, for example, a means of increasing the cooling rate as much as possible is preferred, for example. The cooling temperature is set to 10°C/second or more by water cooling or other means.

(iv) Plane cutting step [Step 4] The flat cutting step [step 4] is a step for removing the surface of hot rolled materials. By performing the plane cutting step [Step 4], the oxide film and defects on the surface produced in the hot rolling step [Step 3] can be removed. The plane cutting conditions in the plane cutting step [Step 4] are not particularly limited as long as they are generally implemented conditions. The amount of removal from the surface of the hot-rolled material by plane cutting can be appropriately adjusted based on the conditions of the hot-rolling step [Step 3] and the oxidation state of the surface of the hot-rolled material. For example, it can be set to the normal value of the surface of the hot-rolled material. The opposite sides are about 0.5 mm to 5 mm respectively.

(v) First cold rolling step [Step 5] The first cold rolling step [Step 5] is a step of cold rolling the hot-rolled material after the plane cutting step [Step 4]. The rolling in the first cold rolling step [Step 5] can be performed at an arbitrary reduction rate according to the product plate thickness. For example, the total processing rate can be set in the range of 50% or more and 99.9% or less.

(vi) First heat treatment step [Step 6] The first heat treatment step [Step 6] is a step of heat treating the cold-rolled material after the first cold rolling step [Step 5] according to the alloy composition.

In the heat treatment of the first heat treatment step [Step 6], by setting the heating temperature to a range of 750°C or more and 1000°C or less, the added element component can be solid-solubilized, so it is possible to improve the performance of the second heat treatment step [Step 8] described below. ] precipitation hardening amount, as a result, the tensile strength of the obtained copper alloy sheet can be improved. In particular, in the heat treatment of the first heat treatment step [Step 6], by setting the heating time at the above-mentioned heating temperature to a range of 1 second or more and 60 seconds or less, more additional element components can be solid-solubilized, and The amount of precipitation hardening in the second heat treatment time step [step 8] can be further increased. On the other hand, when the heating temperature of the heat treatment in the first heat treatment step [Step 6] is lower than 750°C, the Ni component and the Si component cannot be fully dissolved in solid solution, so the amount of precipitation in the second heat treatment time step [Step 8] will decrease. Insufficient, thus the amount of precipitation hardening in the second heat treatment time step [step 8] will become less, so the tensile strength of the obtained copper alloy sheet will become less than 500 MPa. In addition, when the heating temperature of the heat treatment in the first heat treatment step [Step 6] is higher than 1000°C, the tensile strength of the obtained copper alloy sheet will become less than 500 MPa due to the roughening of the grain size, etc. .

(vii) Second cold rolling step [Step 7] The second cold rolling step [Step 7] is a step of further applying cold rolling to the cold-rolled material after the first heat treatment step [Step 6] and is an optional step. That is, in the manufacturing method of the copper alloy plate material of the present invention, it is preferable to further perform the second cold rolling step [Step 7] between the first heat treatment step [Step 6] and the second heat treatment step [Step 8]. Thereby, the amount of precipitation hardening in the second heat treatment time step [step 8] can be further increased. On the other hand, in the method of manufacturing a copper alloy sheet of the present invention, after performing the first heat treatment step [Step 6], the second heat treatment step [Step 8] may be performed without performing the second cold rolling step [Step 7]. ].

Here, the rolling in the second cold rolling step [Step 7] can be performed at an arbitrary processing rate (reduction rate) in accordance with the desired product plate thickness. For example, the total processing rate can be set to 5% or more. And the range is below 70%.

(viii) Second heat treatment step [Step 8] The second heat treatment step [Step 8] is a step of subjecting the cold-rolled material after the second cold rolling step [Step 7] to heat treatment to undergo age hardening.

Here, the heating temperature in the second heat treatment step [Step 8] is set to a range of 450°C or more and 550°C or less. At this time, when the heating temperature is lower than 450°C, the amount of precipitation hardening will be reduced due to insufficient precipitation, so the tensile strength of the obtained copper alloy sheet will become less than 500 MPa. In addition, when the heating temperature is higher than 550°C, the precipitation hardening energy will become lower due to roughening of the crystals, etc., so the tensile strength of the obtained copper alloy sheet will become less than 500 MPa. Therefore, the heat treatment temperature in the second heat treatment step [step 8] needs to be set in the range of 450°C or more and 550°C or less. In particular, from the viewpoint of obtaining higher tensile strength, the heat treatment temperature in the second heat treatment step [step 8] is preferably 470°C or more and 530°C or less.

In addition, the heating time in the second heat treatment step [Step 8] is preferably a holding time in the range of 1 hour or more and 7 hours or less. At this time, when the heating time is shorter than 1 hour or longer than 7 hours, the amount of precipitation hardening will be reduced due to roughening of the crystallized material, etc., resulting in a reduction in the tensile strength of the copper alloy sheet obtained. Therefore, the heating time and holding time in the second heat treatment step [Step 8] are preferably in the range of 1 hour or more and 7 hours or less.

The cold-rolled material after the second heat treatment step [step 8] is preferably cooled immediately. Here, the means for cooling the hot-rolled material is not particularly limited, and means such as water cooling, air cooling, and natural cooling can be used. For example, when cooling is performed by water cooling, the cooling rate may be set to 50° C./sec or more. In addition, when cooling by natural cooling, the cooling rate may be set in the range of 50° C./hour or more and 100° C./hour or less.

(ix) Finishing step [Step 9] The finishing step [Step 9] is to perform two or more sets of cold rolling and heat treatment on the cooled cold-rolled material to adjust the tensile strength and temperature coefficient of resistance (TCR) of the plate. whole steps. More specifically, the finishing step [Step 9] consists of two or more passes of finishing cold rolling [Step 9-1] and finishing performed after each pass of finishing cold rolling [Step 9-1]. Heat treatment [step 9-2] consists of. By performing two or more sets of finishing cold rolling [step 9-1] and finishing heat treatment [step 9-2], the dislocation introduced by cold rolling can be stabilized by the finishing heat treatment, thereby making it possible to Disperse dislocations at high density. By dispersing dislocations at high density in this way, the area ratio of crystal grains with a GROD value in the range of 0° to 5° can be controlled to a range of 20% to 82%, etc., thereby improving the obtained Tensile strength of copper alloy sheets and reduced temperature coefficient of resistance (TCR). On the other hand, when only one set of finishing cold rolling [step 9-1] and finishing heat treatment [step 9-2] is performed, the dislocation cannot be dispersed at high density, so the tensile strength of the obtained copper alloy sheet will become less than 500 MPa.

Among them, in the finishing cold rolling [step 9-1], the maximum partial processing rate of each pass is in the range of 4% or more and 10% or less, and the total processing rate is in the range of 10% or more and 40% or less. Here, the so-called "partial processing rate per pass" is a value obtained by subtracting the cross-sectional area of the plate before a rolling pass included in the finishing cold rolling [Step 9-1] to perform the rolling. The cross-sectional area of the plate after the rolling pass is divided by the cross-sectional area of the plate before the rolling pass and then multiplied by 100 (%). In addition, the so-called "total processing rate" is the following value: the cross-sectional area of the cold-rolled material before the initial finish cold rolling [step 9-1] is subtracted from the cross-sectional area after the final finish cold rolling [step 9-1] The cross-sectional area of the cold-rolled material and divide the obtained value by the cross-sectional area of the cold-rolled material before finishing cold rolling [Step 9-1] is initially performed and then multiply by the value (%) of 100. Among them, the partial processing rate only needs to be rolled in the range of 4% or more and 10% or less in at least one pass among the two or more passes. In other passes, rolling can be performed with a partial processing rate of less than 4%. Processing rate to implement. At this time, when the maximum value of the partial processing rate in each pass is less than 4%, even if the heat treatment is repeatedly performed, the effect of increasing the tensile strength will become smaller, so the tensile strength of the obtained copper alloy sheet will become smaller. is less than 500 MPa. On the other hand, in the finishing cold rolling [step 9-1], it is assumed that rolling in which the partial processing rate exceeds 10% per pass is not performed. If rolling is performed with a partial processing rate exceeding 10% per pass, the amount of misalignment will increase and sufficient stabilization will not be possible. Therefore, the area ratio of grains with a GROD value in the range of 0° or more and 5° or less will decrease. becomes less than 20%, and in addition, the temperature coefficient of resistance (TCR) becomes greater than 3000 ppm/℃. In particular, from the viewpoint of further improving the tensile strength by reducing the number of finishing heat treatments [Step 9-2], finishing cold rolling [Step 9-1] is preferably performed in five passes or less. It is best to practice it in 2 passes.

In addition, when the total processing rate in finish cold rolling [step 9-1] is less than 10%, the amount of work hardening will become less, so the tensile strength of the copper alloy sheet cannot be sufficiently improved, so the obtained copper alloy sheet The tensile strength will become less than 500 MPa. On the other hand, when the total processing rate in finish cold rolling [step 9-1] exceeds 40%, the area ratio of grains with a GROD value in the range of 0° or more and 5° or less will be less than 20%, resulting in The temperature coefficient of resistance (TCR) becomes greater than 3000 ppm/℃. Therefore, the total processing rate in finish cold rolling [step 9-1] needs to be set in the range of 10% or more and 40% or less. In particular, from the viewpoint of improving the balance between tensile strength and temperature coefficient of resistance, the total processing rate in finish cold rolling [Step 9-1] is preferably set to a range of 10% or more and 30% or less. More The ideal range is between 17% and 30%.

In the finishing heat treatment [step 9-2], the heating temperature is in the range of 300°C or more and 400°C or less. In particular, from the viewpoint of obtaining higher tensile strength, the heating temperature in the finishing heat treatment [step 9-2] is preferably in the range of 300°C or more and 380°C or less. At this time, when the heating temperature is less than 300°C, the area ratio of the grains with a GROD value in the range of 0° to 5° will be less than 20%, so the temperature coefficient of resistance (TCR) will become greater than 3000 ppm/ ℃. On the other hand, if the heating temperature is higher than 400°C, the tensile strength of the copper alloy sheet obtained will become less than 500 MPa due to excessive recovery of dislocations and roughening of crystallized products. Further, if the heating temperature in the heat treatment of the first heat treatment step [step 6] is higher than 1000°C or less and the heating temperature in the finishing heat treatment [step 9-2] is higher than 400°C, the GROD value is above 0° and 5 The area ratio of grains in the range below ° becomes higher than 82%. In addition, the heating time in the finishing heat treatment [step 9-2] is not particularly limited, but can be set in the range of 10 seconds or more and 60 seconds or less, for example.

[6]Uses of copper alloy plates The copper alloy plate of the present invention is suitable for electrical and electronic parts, etc. More specifically, it is suitable for use in application products through which current with high current density flows, such as connectors, lead frames, relays, switches, etc. for electrical and electronic equipment.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments and includes all aspects included in the concept of the present invention and the patentable scope of the invention. Various modifications can be made within the scope of the present invention. All kinds of changes. [Example]

Next, in order to further clarify the effects of the present invention, examples of the present invention and comparative examples will be described. However, the present invention is not limited to these examples of the present invention.

(Inventive Examples 1 to 17 and Comparative Examples 1 to 13) Various copper alloy materials having the alloy compositions shown in Table 1 are melted in a high-frequency melting furnace, cooled in the atmosphere and then cast in a melting and casting step [Step 1] to obtain an ingot. For this ingot, a homogenization step [step 2] of heat treatment is performed under the conditions of a heating temperature of 850°C or more and 1000°C or less and a heating time of 1 hour, and immediately thereafter it is performed so that the total processing rate becomes 50% or more. The hot-rolling treatment [step 3] of rolling is performed so that the longitudinal direction of the ingot becomes the rolling direction, and a hot-rolled material is obtained. After that, it was cooled to room temperature by water cooling.

For the cooled hot-rolled material, the surface cutting step [Step 4] is performed to remove about 0.5 mm to 5 mm from both front and back sides to remove the oxide film, and the total machining rate is 90%. , the first cold rolling step [step 5] of rolling such that the longitudinal direction of the hot-rolled material becomes the rolling direction is performed.

The rolled material after the first cold rolling step [Step 5] was subjected to the first heat treatment step [Step 6] of heat treatment under the conditions described in Table 2, and then, the total processing rate [%] described in Table 2 was performed. ] conditions, the second cold rolling step [step 7] of rolling so that the longitudinal direction of the rolled material becomes the rolling direction is performed.

The rolled material after the second cold rolling step [Step 7] is subjected to the second heat treatment step [Step 8] of heat treatment under the heating temperature and heating time conditions described in Table 2, and is immediately cooled by water cooling. to room temperature.

For the cooled rolled material, finish cold rolling [step 9-1] and finish heat treatment [step 9-2] are performed as the finishing step [step 9]. The finish cold rolling [step 9-1] Cold rolling is carried out with the number of passes and the partial processing rate of each pass recorded in Table 2. The finishing heat treatment [Step 9-2] is performed after each pass of the finishing cold rolling [Step 9-1]. The heat treatment was performed at the heating temperature and heating time described in Table 2. At this time, the total processing rate in finish cold rolling [Step 9-1] is as described in Table 2.

In addition, in Table 1, structural components other than copper (Cu), nickel (Ni), Co (cobalt), and Si (silicon) are described as optional additive components. In addition, in Table 1, the column of a component not included in the alloy composition of the copper alloy material is written as a horizontal line "-", which clearly indicates that the component is not included or that even if the component is included, it is less than the detection limit value.

[Various measurement and evaluation methods] Using the copper alloy sheets in the above-mentioned examples of the present invention and comparative examples, the following characteristic evaluations were performed. The evaluation conditions for each characteristic are as follows.

[1] GROD value and area ratio of copper alloy plates The GROD value of the copper alloy plate is obtained from the crystal orientation analysis data, which is based on the use of a high-resolution scanning analytical electron microscope attached to the copper alloy plate obtained in the examples of the present invention and the comparative example (Japan Electronics Co., Ltd. The EBSD detector manufactured by the company, JSM-7001FA) continuously measures, and then calculates it using analysis software (manufactured by TSL Corporation, OIM Analysis) based on the measured crystal orientation data. The measurement was performed in a visual field area of approximately 400 μm × 800 μm under the condition that the distance between measurement points (hereinafter also referred to as step size) was 0.5 μm. The measurement area is carried out on the cross-section including the rolling direction and the thickness direction. The cross-section including the rolling direction and the thickness direction is finished by mechanical grinding and polishing (silica gel) of the copper alloy plate embedded in the resin. Here, when the plate thickness is less than 800 μm, the measurement range can be increased along the rolling direction so that the measurement surface becomes the same size as 400 μm×800 μm. The analysis based on the analysis software sets the measurement points with a reliability index CI value of 0.1 or above as the analysis object. Furthermore, when a boundary with a misalignment of 15° or more is defined as a grain boundary, and the outline of a crystal grain is drawn based on the grain boundary, the measurement point with the smallest KAM value in the crystal grain is regarded as the standard for each crystal grain. points, and then find the misdirections relative to these reference points for all the measurement points that are the target of analysis, thereby calculating the GROD values of the measurement points that are the target of analysis. With respect to the total number of measurement points at which the GROD value is obtained in this way, the number of measurement points with a GROD value between 0° and 5° is determined from the ratio of the number of measurement points with a GROD value in the range of 0° or more and 5° or less. The area ratio of the range of grains. Furthermore, in this example, those with a GROD value in the range of 0° to 5° and an area ratio of crystal grains in a range of 20% to 82% were set as passing grades. The results are shown in Table 3.

[2] Determination of tensile strength of copper alloy plates The tensile strength was measured using two test pieces No. 13B specified in Japanese Industrial Standard JIS Z2241, and the average value of the tensile strengths obtained from the two test pieces was taken as the measured value. The sheet is a sample material cut so that the direction parallel to the rolling direction becomes the length direction. Here, the test piece is made of a plate with a thickness of 0.3 mm. Furthermore, in this example, the tensile strength of the copper alloy plate material was 500 MPa or more as a passing grade. The results are shown in Table 3.

[3] Measurement of temperature coefficient of resistance (TCR) Regarding Examples 1 to 17 of the present invention and Comparative Examples 1 to 13, the obtained copper alloy plate with a thickness of 0.3 mm was cut into a width of 10 mm and a length of 300 mm to prepare a sample material.

The temperature coefficient of resistance (TCR) is measured using a four-terminal method stipulated in Japanese Industrial Standards JIS C2526, with the distance between voltage terminals set to 200 mm and the measurement current set to 100 mA. The voltage when the temperature is heated is 150°C, and the resistance value R _{150 °C} [mΩ] at 150°C is obtained from the obtained value. Next, the voltage when the temperature of the sample material was cooled to 200°C was measured, and the resistance value R _{20 °C} [mΩ] at 20°C was determined from the obtained value. Then the obtained resistance value is the value of R _{150 ℃} and R _{20 ℃} , based on TCR={(R _{150 ℃} [mΩ]-R _{20 ℃} [mΩ])/R _{20 ℃} [mΩ]}×{1/ The resistance temperature coefficient (ppm/℃) in the temperature range from 20℃ to 150℃ is calculated using the formula of (150[℃]-20[℃])}×10 ⁶ . Furthermore, in this example, a temperature coefficient of resistance (TCR) of 3000 ppm/°C or less was set as a pass level. The results are shown in Table 3.

[Table 1]

[Table 2]

[table 3]

Based on the results in Tables 1 to 3, the alloy compositions of the copper alloy sheets of Examples 1 to 17 of the present invention are within the appropriate range of the present invention, and the GROD value measured using the EBSD method is between 0° and 5°. The area ratio of the crystal grains in the range is in the range of 20% or more and 82% or less. In this case, it is evaluated as: the tensile strength is 500 MPa or more and the temperature coefficient of resistance in the temperature range from 20°C to 150°C (TCR) is below 3000 ppm/℃.

Therefore, the copper alloy plates of Examples 1 to 17 of the present invention have high tensile strength and a small temperature coefficient of resistance (TCR).

In particular, it is considered that the maximum value of the partial processing rate for each pass in the finishing cold rolling [Step 9-1] of the copper alloy sheet of Example 5 of the present invention becomes larger than that of the copper alloy sheet of Example 4 of the present invention. Moreover, the number of finishing heat treatments [Step 9-2] is reduced, further improving the tensile strength.

In addition, when the heating temperature in the second heat treatment step [step 8] of the copper alloy sheet of Example 6 of the present invention is 500°C, it is better than the copper alloy sheet of Examples 5 and 7 of the present invention when the heating temperatures are 450°C and 550°C. , a higher tensile strength can be obtained. Therefore, from the viewpoint of obtaining a higher tensile strength, it is considered preferable to set the heating temperature in the second heat treatment step [Step 8] to about 500°C.

In addition, the copper alloy sheet of Example 8 of the present invention, when the total processing rate in the finish cold rolling [step 9-1] is 17%, is better than the copper alloy sheet of Example 6 of the present invention when the total processing rate is 13%. , higher tensile strength can be obtained, and compared with the copper alloy plate of Example 9 of the present invention with a total processing rate of 38%, the temperature coefficient of resistance (TCR) is smaller. Therefore, the tensile strength and temperature coefficient of resistance are obtained from From the viewpoint of producing a copper alloy plate with better balance, it is considered that it is preferable to set the total processing rate to about 17%.

In addition, when the heating temperature in the finishing heat treatment [step 9-2] of the copper alloy sheet of Example 10 of the present invention is 300°C, it is better than the copper alloy sheet of Example 6 of the present invention and the heating temperature of 350°C. When the copper alloy plate of Example 11 of the present invention is heated to 400°C, higher tensile strength can be obtained. It is considered that the reason why the tensile strength of the copper alloy sheets of Examples 6 and 11 of the present invention is slow is that the heating temperature in the finishing heat treatment [step 9-2] is high and the cold-rolled material is slightly softened. Therefore, from the viewpoint of obtaining higher tensile strength, it is considered preferable to set the heating temperature in the finishing heat treatment [Step 9-2] to about 300°C.

In addition, when the heating temperature in the finishing heat treatment [step 9-2] of the copper alloy sheet of Example 11 of the present invention is 400°C, it is better than the copper alloy sheet of Example 6 of the present invention and the heating temperature of 350°C. When the copper alloy plate of Example 6 of the present invention is heated to 300°C, the temperature coefficient of resistance (TCR) becomes smaller. Therefore, from the viewpoint of obtaining a smaller temperature coefficient of resistance (TCR), it is considered preferable to set the heating temperature in the finishing heat treatment [step 9-2] to about 400°C.

In addition, for the copper alloy sheets of Examples 14 and 15 of the present invention, the total content of Ni and Co, the heating temperature in the second heat treatment step [Step 8], and the total processing rate in the finishing cold rolling [Step 9-1] are all within Within a preferred range, it is believed that a copper alloy plate with better tensile strength and temperature coefficient of resistance can be obtained.

On the other hand, in the copper alloy sheets of Comparative Examples 1 to 13, at least one of the alloy composition, the tensile strength, and the area ratio of the crystal grains with a GROD value in the range of 0° or more and 5° or less is appropriate for the present invention. Outside the range, so one or both of the tensile strength and temperature coefficient of resistance (TCR) do not reach the qualified level.

In particular, the heating temperature in the second heat treatment step [step 8] of the copper alloy sheet of Comparative Example 1 was lower than the range of the present invention, so the tensile strength did not reach the acceptable level.

In addition, the heating temperature in the second heat treatment step [Step 8] of the copper alloy plate of Comparative Example 2 was higher than the range of the present invention, so the tensile strength did not reach the acceptable level.

In addition, the total content of Ni and Co in the copper alloy sheet of Comparative Example 3 is less than the range of the present invention, so the temperature coefficient of resistance (TCR) does not reach the acceptable level.

In addition, the Si content of the copper alloy sheet of Comparative Example 4 is less than the range of the present invention, so the tensile strength does not reach the acceptable level.

In addition, the total processing rate in the finish cold rolling [Step 9-1] of the copper alloy sheet of Comparative Example 5 was lower than the range of the present invention, so the tensile strength did not reach the acceptable level.

In addition, since the total processing rate in the finish cold rolling [step 9-1] of the copper alloy sheet of Comparative Example 6 is higher than the range of the present invention, the area of the grains with a GROD value in the range of 0° or more and 5° or less The ratio is lower than the range of the present invention, and as a result, the temperature coefficient of resistance (TCR) does not reach the acceptable level.

In addition, since the heating temperature in the finishing heat treatment [Step 9-2] of the copper alloy sheet of Comparative Example 7 is lower than the range of the present invention, the area ratio of crystal grains with a GROD value in the range of 0° or more and 5° or less is low. Within the scope of the present invention, as a result, the temperature coefficient of resistance (TCR) did not reach an acceptable level.

In addition, since the heating temperature in the finishing heat treatment [Step 9-2] of the copper alloy sheet of Comparative Example 8 was higher than the range of the present invention, the tensile strength did not reach the acceptable level.

In addition, since the maximum value of the partial processing rate of each pass in the finishing cold rolling [step 9-1] of the copper alloy sheet of Comparative Example 9 is higher than the range of the present invention, the GROD value is above 0° and below 5° The area ratio of the crystal grains in the range is lower than the range of the present invention, and as a result, the temperature coefficient of resistance (TCR) does not reach the acceptable level.

In addition, since the maximum value of the partial processing rate of each pass in the finishing cold rolling [Step 9-1] of the copper alloy sheet of Comparative Example 10 is lower than the range of the present invention, the finishing heat treatment [Step 9-2] As a result, the tensile strength did not reach the acceptable level.

In addition, since the heating temperature in the first heat treatment step [Step 6] of the copper alloy sheet of Comparative Example 11 was lower than the range of the present invention, it is considered that the aging strength could not be obtained, and as a result, the tensile strength did not reach the acceptable level.

In addition, since the heating temperature in the first heat treatment step [Step 6] of the copper alloy sheet of Comparative Example 12 was higher than the range of the present invention, it is considered that the grains were roughened, and as a result, the tensile strength did not reach the acceptable level. level.

In addition, since the heating temperature of the copper alloy sheet of Comparative Example 13 in the first heat treatment step [Step 6] is higher than the range of the present invention, the total processing rate in the finishing cold rolling [Step 9-1] is lower than that of the present invention. range and the heating temperature in the finishing heat treatment [step 9-2] is higher than the range of the present invention, so the area ratio of the crystal grains with a GROD value in the range of 0° or more and 5° or less is higher than the range of the present invention, As a result, the tensile strength did not reach the acceptable level.

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Claims (2)

A copper alloy sheet having the following alloy composition: at least one component of Ni and Co in a total amount of 0.50 mass % or more and 5.00 mass % or less, Si in a range of 0.10 mass % or more and 1.50 mass % or less, and the remainder Composed of Cu and unavoidable impurities, When the GROD value is measured using the EBSD method on a cross-section including the rolling direction and the thickness direction of the copper alloy sheet, the measured area ratio of the grains with the GROD value in the range of 0° or more and 5° or less is more than 20%. And the range below 82%, The tensile strength is above 500 MPa and The temperature coefficient of resistance (TCR) in the temperature range from 20°C to 150°C is 3000 ppm/°C or less. The copper alloy sheet according to claim 1, wherein the alloy composition further contains a group selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr in a total range of 0.10 mass% or more and 1.00 mass% or less. at least one ingredient in .