Copper alloy material, and resistance material for resistor using same, and resistor

Abstract

The problem to be solved by the present invention is to provide: a copper alloy material which has little chiseling of the copper alloy material during press working, has sufficiently high volume resistivity, and can be used as a resistance material for a resistor and a resistor using the copper alloy material; the temperature coefficient of resistance (TCR) is negative and has a small absolute value, and the absolute value for copper thermoelectromotive force (EMF) is small. In order to solve the problem, the copper alloy material has an alloy composition containing 20.0 mass% or more and 35.0 mass% or less of Mn and 6.5 mass% or more and 17.0 mass% or less of Ni, with the remainder being Cu and unavoidable impurities; in a longitudinal cross section including the extension direction and the thickness direction of the copper alloy material, when an orientation distribution function (ODF) obtained by crystal orientation analysis by the SEM-EBSD method is represented by Euler angles ([phi] 1, [phi], and [phi] 2), the maximum value of the orientation density is 6.0 or less when [phi] 1 = 0-90 DEG, [phi] = 0-90 DEG, and [phi] 2 is 15 DEG, 20 DEG, and 25 DEG.

Description

Technical Field

[0001] The present invention relates to a copper alloy material, a resistive material for a resistor, and a resistor using the copper alloy material. Background Art

[0002] As a metal material for a resistive material of a resistor, it is desired that the resistance of the resistor remains stable even when the ambient temperature changes. Therefore, for the resistive material, it is required that the absolute value of the resistance temperature coefficient (TCR) is small. The resistance temperature coefficient is an index indicating the characteristic that the resistance value is stable with respect to temperature change. The so-called resistance temperature coefficient represents the magnitude of the change in the resistance value caused by temperature in parts per million (ppm) per 1°C, and can be expressed by the following formula: TCR (×10 -6 / °C) = {(R - R0) / R0} × {1 / (T - T0)} × 10 6 . Here, T in the formula represents the test temperature (°C), T0 represents the reference temperature (°C), R represents the resistance value (Ω) at the test temperature T, and R0 represents the resistance value (Ω) at the reference temperature T0. In particular, the TCR of Cu-Mn-Ni alloy and Cu-Mn-Sn alloy is very small, so they are widely used as alloy materials constituting the resistive material.

[0003] However, for example, when using these Cu-Mn-Ni alloys and Cu-Mn-Sn alloys as resistive materials in a resistor designed to have a specified resistance value by forming a circuit (pattern) using the resistive material, since the volume resistivity is as small as less than 50×10 －8 (Ω·m), it is necessary to reduce the cross-sectional area of the resistive material to increase the resistance value of the resistor. In such a resistor, there are the following disadvantages: when a large current temporarily flows into the circuit or when a certain degree of relatively large current continuously flows in, the Joule heat generated in the resistive material with a smaller cross-sectional area becomes higher and generates heat, and as a result, the resistive material becomes easily broken (fused) due to heat.

[0004] Therefore, in order to suppress the reduction of the cross-sectional area of the resistive material, a resistive material with a larger volume resistivity is being sought.

[0005] For example, in Patent Document 1, it is considered that in a copper alloy containing Mn in the range of 23% by mass or more and 28% by mass or less and containing Ni in the range of 9% by mass or more and 13% by mass or less, by making the mass fraction of Mn and the mass fraction of Ni constitute a thermoelectromotive force with respect to copper of less than ±1 μV / °C at 20°C, a copper alloy can be obtained, and the copper alloy can obtain 50×10 －8a relatively high resistance (volume resistivity ρ) of 100 [Ω·m] or more, a small thermoelectromotive force with respect to copper (thermoelectromotive force with respect to copper, EMF), a low temperature coefficient of resistance, and a relatively high stability (time invariance) of the inherent resistance with respect to time.

[0006] In addition, Patent Document 2 states that in an alloy for a resistor body containing copper, manganese, and nickel, when Mn is contained in a range of 33% by mass or more and 38% by mass or less, and Ni is contained in a range of 8% by mass or more and 15% by mass or less, it will have characteristics close to those of a nickel-chromium alloy (especially relative resistance), and a copper-manganese-nickel alloy with more excellent workability than a nickel-chromium alloy can be obtained.

[0007] [Prior Art Documents]

[0008] (Patent Documents)

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-528376.

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2021-161512. Summary of the Invention

[0011] [Problems to be Solved by the Invention]

[0012] With the recent miniaturization and high integration of electrical and electronic components, resistors or resistor materials used for the resistors have also been gradually miniaturized. Resistor materials used for resistors are generally formed by applying cutting processes such as stamping. Therefore, in order to reduce the deviation of the resistance value, a copper alloy material is required to have excellent stamping workability. In particular, a method is sought such that when stamping a copper alloy material, the cut surface as the punched surface is formed at a fixed position to reduce the variation of the resistance value.

[0013] However, in a copper alloy containing Mn and Ni at a high concentration to increase the volume resistivity, solid solution strengthening continues, so it has the characteristics of high mechanical strength and strong bonding force between atoms constituting the copper alloy. On the other hand, in such a copper alloy, when punching is performed by pressing after forming into a sheet, due to the strong bonding force between atoms, it has the characteristic that the cut surface, especially the fracture surface, is easily scratched. When the fracture surface is scratched, the cross-sectional area of the resistor material obtained by stamping is partially reduced near the cut surface, so the precision of the resistance in the resistor material may be impaired.

[0014] Furthermore, in recent years, in the electronic systems of electric vehicles, etc., as resistors such as shunt resistors and chip resistors, in addition to requiring a large volume resistivity ρ, high precision for use in an environment that can withstand higher temperatures is also required. Also, for copper alloys used for such resistors, high precision for use in an environment that can withstand higher temperatures is required. More specifically, when the volume resistivity ρ is large and the usage environment in a wide temperature range from normal temperature to high temperature is considered, a copper alloy material is required that has a negative and small absolute value of the resistance temperature coefficient (TCR), and a small absolute value of the thermal electromotive force (EMF) with respect to copper.

[0015] Accordingly, an object of the present invention is to provide a copper alloy material, a resistive material for resistors, and a resistor using the copper alloy material, the copper alloy material having the following characteristics: small chipping on the punched surface generated during stamping, a sufficiently high volume resistivity, a negative and small absolute value of the resistance temperature coefficient (TCR), and a small absolute value of the thermal electromotive force (EMF) with respect to copper.

[0016] [Technical means for solving the problem]

[0017] The inventors found a copper alloy material having the following alloy composition: containing 20.0 mass% or more and 35.0 mass% or less of Mn and 6.5 mass% or more and 17.0 mass% or less of Ni, with the balance being composed of Cu and unavoidable impurities. At the same time, when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is 6.0 or less. By using the copper alloy material, for example, a copper alloy material can be obtained in which chipping generated during stamping becomes smaller. For example, as a resistive material, it has a sufficiently high volume resistivity ρ, and also considers the usage environment in a wide temperature range from normal temperature (e.g., 20°C) to high temperature (e.g., 150°C). The resistance temperature coefficient (TCR) is negative and has a small absolute value, and the absolute value of the thermal electromotive force (EMF) with respect to copper is small, thus completing the present invention.

[0018] To achieve the above object, the main configuration of the present invention is as follows.

[0019] (1) A copper alloy material having the following alloy composition: containing 20.0% by mass or more and 35.0% by mass or less of Mn and 6.5% by mass or more and 17.0% by mass or less of Ni, with the balance being composed of Cu and unavoidable impurities. In the longitudinal section of the copper alloy material including the rolling direction and the thickness direction, when the orientation distribution function (ODF) obtained by crystal orientation analysis using the SEM-EBSD method is represented by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is 6.0 or less.

[0020] (2) The copper alloy material as described in (1) above, wherein in the aforementioned longitudinal section, the average crystal grain size of the crystal grains obtained from the crystal orientation analysis data using the SEM-EBSD method is 20 μm or less and the standard deviation of the average crystal grain size is 10 μm or less.

[0021] (3) The copper alloy material as described in (1) or (2) above, wherein the aforementioned alloy composition further contains one or both of 0.01% by mass or more and 0.50% by mass or less of Fe and 0.01% by mass or more and 2.00% by mass or less of Co.

[0022] (4) The copper alloy material as described in any one of (1) to (3) above, wherein the aforementioned alloy composition further contains at least one selected from the group consisting of the following components: 0.01% by mass or more and 5.00% by mass or less of Sn, 0.01% by mass or more and 5.00% by mass or less of Zn, 0.01% by mass or more and 0.50% by mass or less of Cr, 0.01% by mass or more and 0.50% by mass or less of Ag, 0.01% by mass or more and 1.00% by mass or less of Al, 0.01% by mass or more and 0.50% by mass or less of Mg, 0.01% by mass or more and 0.50% by mass or less of Si, and 0.01% by mass or more and 0.50% by mass or less of P.

[0023] (5) A resistance material for a resistor, which is composed of the copper alloy material as described in any one of (1) to (4) above.

[0024] (6) A resistor, which is a shunt resistor or a chip resistor, and the resistor has the resistance material for a resistor as described in (5) above.

[0025] (Effect of the Invention)

[0026] According to the present invention, it is possible to provide a copper alloy material, a resistance material for a resistor, and a resistor using the copper alloy material. The copper alloy material has the following characteristics: the chipping of the punched surface during stamping is small, it has a sufficiently high volume resistivity, the resistance temperature coefficient (TCR) is negative and has a small absolute value, and the absolute value of the thermal electromotive force (EMF) with respect to copper is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 FIG. is a schematic view of a stamped copper alloy material viewed from a direction parallel to the cut surface in order to make the contour shape (right edge portion) of the cut surface during stamping of the copper alloy material of the present invention recognizable.

[0028] Figure 2 FIG. is a schematic view for explaining a method of obtaining the thermal electromotive force (EMF) with respect to copper for each test material of the example and comparative example of the present invention.

[0029] Figure 3 FIG. is a graph showing the orientation density in the range of φ1 = 0 to 90° and Φ = 0 to 90° when the orientation distribution function (ODF) of the copper alloy material of Example 14 of the present invention is represented by Euler angles (φ1, Φ, φ2), with φ1 on the horizontal axis and Φ on the vertical axis. Figure 3 (a) is the graph when φ2 = 15°. Figure 3 (b) is the graph when φ2 = 20°. Figure 3 (c) is the graph when φ2 = 25°.

[0030] Figure 4 FIG. is a scanning electron microscope (SEM) photograph of a stamped copper alloy material of the example and comparative example of the present invention when observed from a direction parallel to the cut surface in order to make the contour shape (right edge portion) of the cut surface during stamping recognizable. Figure 4 (a) is the copper alloy material of Example 5 of the present invention. Figure 4 (b) is the copper alloy material of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of the copper alloy material of the present invention will be described in detail. In addition, for the composition of the alloy of the present invention, "%" may sometimes represent "% by mass".

[0032] The copper alloy material according to the present invention has the following alloy composition: containing Mn in an amount of 20.0% by mass or more and 35.0% by mass or less and Ni in an amount of 6.5% by mass or more and 17.0% by mass or less, and the balance being composed of Cu and unavoidable impurities; in the longitudinal section of the copper alloy material including the rolling direction and the thickness direction, when the orientation distribution function (ODF) obtained by crystal orientation analysis using the SEM-EBSD method is represented by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is 6.0 or less.

[0033] By doing so, in the copper alloy material according to the present invention, for the copper alloy material containing Mn in an amount of 20.0% by mass or more and 35.0% by mass or less and Ni in an amount of 6.5% by mass or more and 17.0% by mass or less, when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is set to 6.0 or less. Thereby, grains having similar mechanical properties do not become densely packed to an unnecessary degree, and thus chipping of the fracture surface generated during stamping can be suppressed.

[0034] In addition, in the copper alloy material according to the present invention, Mn is contained in the range of 20.0% by mass or more and 35.0% by mass or less, and Ni is contained in the range of 5.0% by mass or more and 17.0% by mass or less. Thereby, while increasing the volume resistivity ρ, the absolute value of the temperature coefficient of resistance (TCR) (hereinafter, sometimes simply referred to as "temperature coefficient of resistance") in the temperature range of 20°C or more and 150°C or less can be reduced, and the absolute value of the thermal electromotive force against copper can be reduced. Further, in the copper alloy material according to the present invention, the absolute value of the thermal electromotive force against copper (EMF) (hereinafter, sometimes simply referred to as "thermal electromotive force against copper") generated between the temperature environments of 20°C and 80°C becomes small. Therefore, even in a high-temperature environment, high-precision of the resistor can be improved.

[0035] Regarding this point, in the copper alloy described in the above Patent Document 1, in order to reduce the absolute value of the thermal electromotive force against copper (EMF), it is necessary to increase the content of Ni. At this time, the absolute value of the temperature coefficient of resistance (TCR) tends to increase. Further, in the copper alloy described in the above Patent Document 1, regarding the temperature dependence of resistance, for example, as described in Patent Document 1 Figure 3As described, in the temperature range from 20°C to 150°C including a relatively high temperature region, the temperature coefficient of resistance (TCR) becomes a large negative number, so there is a tendency for the resistance value to be prone to error in the high temperature region. However, in the copper alloy material according to the present invention, an increase in the absolute value of the temperature coefficient of resistance (TCR) in the temperature range from 20°C to 150°C can be suppressed. Therefore, it is also excellent in the following aspects: having a sufficiently high volume resistivity ρ as a resistance material, having a small absolute value of the temperature coefficient of resistance considering the use environment in a wide temperature range from normal temperature (e.g., 20°C) to high temperature (e.g., 150°C), and having a small absolute value of the thermal electromotive force with respect to copper.

[0036] As a result, by using the copper alloy material according to the present invention, it is possible to provide a copper alloy material, a resistance material for a resistor, and a resistor using the copper alloy material, and the copper alloy material has the following characteristics: the chipping of the punched surface generated during stamping is small, has a sufficiently high volume resistivity ρ, the temperature coefficient of resistance (TCR) is negative and has a small absolute value, and the absolute value of the thermal electromotive force with respect to copper (EMF) is small.

[0037] [1] Composition of the copper alloy material

[0038] <Essential additive components>

[0039] The alloy composition of the copper alloy material of the present invention contains 20.0 mass% or more and 35.0 mass% or less of Mn and 6.5 mass% or more and 17.0 mass% or less of Ni as essential additive components.

[0040] (Mn: 20.0 mass% or more and 35.0 mass% or less)

[0041] Mn (manganese) is an element that can increase the volume resistivity ρ. In order to exert this effect and obtain a homogeneous copper alloy material, it is preferably contained 20.0 mass% or more of Mn, more preferably 22.0 mass% or more, and even more preferably 24.0 mass% or more. Here, by increasing the Mn content to 22.0 mass% or more or 24.0 mass% or more, the volume resistivity ρ of the copper alloy material can be further increased. On the other hand, if the Mn content exceeds 35.0 mass%, the melting point of the copper alloy material will decrease, making it difficult to control the manufacture of the copper alloy material, especially hot working, and it is difficult to obtain uniform properties. In addition, if the Mn content exceeds 35.0 mass%, the absolute value of the thermal electromotive force with respect to copper (EMF) will tend to increase. Therefore, the Mn content is set in the range of 20.0 mass% or more and 35.0 mass% or less.

[0042] (Ni: 6.5 mass% or more and 17.0 mass% or less)

[0043] Ni (nickel) is an element that can adjust the thermoelectromotive force (EMF) against copper in the positive direction. To exert this effect, it is preferably contained in an amount of 6.5 mass% or more. On the other hand, if the Ni content exceeds 17.0 mass%, it becomes difficult to obtain a uniform structure, and the volume resistivity ρ and the thermoelectromotive force (EMF) against copper may change. In addition, if the Ni content exceeds 17.0 mass%, the thermoelectromotive force (EMF) against copper tends to become a large positive number, and in addition, the absolute value of the resistance temperature coefficient (TCR) tends to increase. Therefore, from the viewpoint of obtaining a copper alloy material having desired properties or a copper alloy material that is easy to manufacture, the Ni content is set in the range of 6.5 mass% or more and 17.0 mass% or less, preferably in the range of 6.5 mass% or more and 12.0 mass% or less, and more preferably in the range of 6.5 mass% or more and 9.0 mass% or less.

[0044] <First optional additive component>

[0045] The alloy composition of the copper alloy material of the present invention can further contain one or both of Fe in an amount of 0.01 mass% or more and 0.50 mass% or less and Co in an amount of 0.01 mass% or more and 2.00 mass% or less as optional additive components. In particular, by containing one or both of Fe and Co, the absolute value of the resistance temperature coefficient (TCR) can be further reduced.

[0046] (Fe: 0.01 mass% or more and 0.50 mass% or less)

[0047] Fe (iron) is an element that can adjust the thermoelectromotive force (EMF) against copper in the positive direction. To exert this effect, it is preferably contained in an amount of 0.01 mass% or more. On the other hand, if the content of Fe exceeds 0.50 mass%, it becomes difficult to obtain a uniform structure, and the electrical properties are likely to deviate. In particular, from the viewpoint of further improving the stability of the electrical properties against heat and the like and further improving the reliability when used for a long time in a resistance material or the like made therefrom, the Fe content is preferably set to 0.20 mass% or less. In particular, from the viewpoint of further improving the reliability when used for a long time, it is preferable to contain Co rather than Fe. That is, it is preferable to contain Co described below as necessary and not contain Fe. Thus, the content of Fe is preferably set in the range of 0.01 mass% or more and 0.50 mass% or less, and more preferably in the range of 0.01 mass% or more and 0.20 mass% or less.

[0048] (Co: 0.01 mass% or more and 2.00 mass% or less)

[0049] Co (Cobalt) is an element that can adjust the thermoelectromotive force (EMF) against copper towards the positive direction. To exert this effect, it is preferably to contain Co of 0.01 mass% or more. On the other hand, if the content of Co exceeds 2.00 mass%, it becomes difficult to obtain a uniform structure, so that the electrical properties are likely to deviate. Therefore, the content of Co is preferably set within the range of 0.01 mass% or more and 2.00 mass% or less.

[0050] <Second optional additive component>

[0051] The alloy composition of the copper alloy material of the present invention, as an optional additive component, can further select at least one from the group consisting of containing the following components: Sn of 0.01 mass% or more and 5.00 mass% or less, Zn of 0.01 mass% or more and 5.00 mass% or less, Cr of 0.01 mass% or more and 0.50 mass% or less, Ag of 0.01 mass% or more and 0.50 mass% or less, Al of 0.01 mass% or more and 1.00 mass% or less, Mg of 0.01 mass% or more and 0.50 mass% or less, Si of 0.01 mass% or more and 0.50 mass% or less, and P of 0.01 mass% or more and 0.50 mass% or less.

[0052] (Sn: 0.01 mass% or more and 5.00 mass% or less)

[0053] Sn (Tin) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Sn of 0.01 mass% or more. On the other hand, by setting the Sn content to 5.00 mass% or less, it is possible to make it less likely to occur that the manufacturability is reduced due to the embrittlement of the copper alloy material.

[0054] (Zn: 0.01 mass% or more and 5.00 mass% or less)

[0055] Zn (Zinc) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Zn of 0.01 mass% or more. On the other hand, since it may have an adverse effect on the stability of the electrical properties of resistors such as the volume resistivity ρ and the thermoelectromotive force (EMF) against copper, the Zn content is preferably set to 5.00 mass% or less.

[0056] (Cr: 0.01 mass% or more and 0.50 mass% or less)

[0057] Cr (Chromium) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Cr of 0.01 mass% or more. On the other hand, since it may have an adverse effect on the stability of the electrical properties of resistors such as the volume resistivity ρ and the thermoelectromotive force (EMF) against copper, the Cr content is preferably set to 0.50 mass% or less.

[0058] (Ag: 0.01 mass % or more and 0.50 mass % or less)

[0059] Ag (silver) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Ag of 0.01 mass % or more. On the other hand, since it may have an adverse effect on the stability of the electrical properties of the resistor such as the volume resistivity ρ and the thermal electromotive force (EMF) against copper, the Ag content is preferably set to 0.50 mass % or less.

[0060] (Al: 0.01 mass % or more and 1.00 mass % or less)

[0061] Al (aluminum) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Al of 0.01 mass % or more. On the other hand, since it may embrittle the copper alloy material, the Al content is preferably set to 1.00 mass % or less.

[0062] (Mg: 0.01 mass % or more and 0.50 mass % or less)

[0063] Mg (magnesium) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Mg of 0.01 mass % or more. On the other hand, since it may embrittle the copper alloy material, the Mg content is preferably set to 0.50 mass % or less.

[0064] (Si: 0.01 mass % or more and 0.50 mass % or less)

[0065] Si (silicon) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain Si of 0.01 mass % or more. On the other hand, since it may embrittle the copper alloy material, the Si content is preferably set to 0.50 mass % or less.

[0066] (P: 0.01 mass % or more and 0.50 mass % or less)

[0067] P (phosphorus) is a component that can be used to adjust the volume resistivity ρ. To exert this effect, it is preferably to contain P of 0.01 mass % or more. On the other hand, since it may embrittle the copper alloy material, the P content is preferably set to 0.50 mass % or less.

[0068] (Total amount of the second optional additive components: 0.01 mass % or more and 5.00 mass % or less)

[0069] In order to obtain the effects produced by the second optional additive component composed of at least one component selected from the group consisting of Sn, Zn, Cr, Ag, Al, Mg, Si, and P, these second optional additive components preferably contain 0.01% by mass or more in total. On the other hand, if the content of these second optional additive components is contained in a large amount, the electrical properties will become unstable and it will be difficult to manufacture the copper alloy material. Therefore, it is preferably set to 5.00% by mass or less in total.

[0070] <The balance: Cu and unavoidable impurities>

[0071] Except for the above-mentioned essential components and optional additive components, the balance is composed of Cu (copper) and unavoidable impurities. In addition, the so-called "unavoidable impurities" referred to here mean an impurity that generally exists in the raw materials or is unavoidably mixed in during the manufacturing process and is not originally required in copper-based products, but is tolerable because it is in trace amounts and does not have an adverse effect on the properties of copper-based products. Examples of the components that can be listed as unavoidable impurities include non-metallic elements such as sulfur (S); and metallic elements such as antimony (Sb). In addition, the upper limit of the content of these components can be set to: 0.05% by mass for each of the above components, and 0.10% by mass for the total amount of the above components.

[0072] [2] The maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° when the orientation distribution function (ODF) is expressed in Euler angles

[0073] In the longitudinal section of the copper alloy material of the present invention, which includes the rolling direction and the thickness direction, when the orientation distribution function (ODF) obtained by crystal orientation analysis using the SEM-EBSD method is represented by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° is 6.0 or less. Copper alloy materials containing a large amount of Mn and Ni, such as those of the present invention, tend to have grains easily aligned in specific orientations such as the S orientation and the Copper orientation. Here, if the alignment in a specific orientation becomes dominant, grains with similar mechanical characteristics will become dense. In this case, when stamping is performed, the gouging of the fracture surface in the fracture surface tends to become larger. Therefore, in order to suppress the gouging of the fracture surface during stamping, it is necessary to suppress the alignment of grains in a specific orientation. Thus, the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2) is set to 6.0 or less, respectively. By setting the maximum value of the orientation density within this range to 6.0 or less, grains aligned in specific orientations such as the S orientation and the Copper orientation do not accumulate more than necessary, so grains with similar mechanical characteristics do not become dense. Therefore, the gouging of the fracture surface generated during stamping can be suppressed, and a flatter cut surface can be obtained. As a result, even near the cut surface, the cross-sectional area of the resistor material obtained by stamping is less likely to be damaged due to the gouging of the fracture surface, so an appropriate copper alloy material can be obtained, and a resistor with higher precision can be obtained.

[0074] Thus, from the viewpoint of suppressing the gouging of the fracture surface generated during stamping and being suitable for obtaining a copper alloy material for a resistor with higher precision, it is preferable that the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2) is 6.0 or less, and more preferably 5.7 or less.

[0075] The maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2) is a value obtained by crystal orientation analysis using the SEM-EBSD method.

[0076] Here, the crystal orientation analysis data of the SEM-EBSD method can be obtained in the following manner: After producing a cross-sectional specimen by mirror-polishing a cross-section parallel to the elongation direction of the copper alloy material, a field emission scanning electron microscope (FE-SEM) is used for observation and EBSD measurement (measurement by electron backscatter diffraction) is carried out. The area to be set as the measurement object in the EBSD measurement can be set to 0.2 mm 2 Above, the step size during measurement can be set to 0.5 μm.

[0077] Based on the measurement results obtained from this EBSD measurement, the maximum value of the orientation density can be obtained using an ODF map, which is obtained using "OIM ANALYSIS" as analysis software. More specifically, using the harmonic series expansion, the series rank is set to 16, and the half-width at half maximum (Gaussian Half-Width) when fitting a Gaussian distribution is set to 5° to perform intensity calculation. The calculation results obtained are placed into the option of Enforce Orthotropic Sample Symmetry to perform aggregate structure analysis, whereby an ODF map showing the intensity distribution of the crystal orientation represented by Euler angles (φ1, Φ, φ2) is plotted, and using this map, the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° can be obtained.

[0078] In addition, the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° when representing the orientation distribution function (ODF) by Euler angles (φ1, Φ, φ2) is represented as a relative value, which is relative to the case where the density of the grains oriented to the Euler angles (φ1, Φ, φ2) when all the grains are randomly oriented is set to 1.

[0079] [3] The average crystal grain size and its standard deviation of the grains of the copper alloy material

[0080] The copper alloy material of the present invention is preferably in the range where the average crystal grain size of the grains is 20 μm or less and the standard deviation of the average crystal grain size is 10 μm or less. Thereby, when stamping processing is performed on the copper alloy material, the chipping of the fracture surface as the punching processing surface can be further reduced.

[0081] Here, the average crystal grain diameter and its standard deviation of the crystal grains of the copper alloy material can be obtained from the crystal orientation analysis data of the SEM-EBSD method for a longitudinal section of the copper alloy material including the extension direction and the thickness direction. More specifically, it can be obtained from a graph of Grain Size (diameter). The grain size is obtained using "OIM ANALYSIS" as the analysis software. At this time, the average diameter and the standard deviation obtained from the Area Fraction can be set as the average crystal grain diameter and its standard deviation of the crystal grains.

[0082] [4] Shape of the copper alloy material

[0083] The shape of the copper alloy material of the present invention is not particularly limited. However, from the viewpoint of facilitating the subsequent processing steps such as hot working or cold working and cutting processing such as stamping, a sheet material is preferred. Here, for a copper alloy material formed by rolling such as a sheet material, the rolling direction can be set as the extension direction. On the other hand, the copper alloy material of the present invention can be a wire, a square wire, a strip, a bar, or a rod, etc. By forming these shapes using the copper alloy material of the present invention, it becomes easy to perform cutting processing on the ends. Here, in these copper alloy materials formed by wire drawing, drawing, or extrusion, any one of the wire drawing direction, the drawing direction, and the extrusion direction can be set as the extension direction.

[0084] [5] An example of the manufacturing method of the copper alloy material

[0085] The above copper alloy material can be realized by combining and controlling the alloy composition and the manufacturing process, and the manufacturing process is not particularly limited. Among these, as an example of the manufacturing process capable of obtaining the above copper alloy material, the following method can be cited.

[0086] As an example of the method for manufacturing the copper alloy material of the present invention, a copper alloy raw material having an alloy composition substantially the same as that of the above copper alloy material is subjected to at least the casting step [Step 1], the homogenization heat treatment step [Step 2], the hot working step [Step 3], and the first heat treatment step [Step 4] in sequence. After that, the cold working step and the heat treatment step are repeatedly performed more than 2 times, and more preferably, more than 4 times. Among them, in the homogenization heat treatment step [Step 2], the heating temperature is set in the range of 750 °C or higher and 900 °C or lower, and the temperature holding time at the heating temperature is set in the range of 10 minutes or longer and 10 hours or shorter. In addition, for the cold working steps repeatedly performed after the first heat treatment step [Step 4], the total processing rate is set in the range of 40% or higher and 65% or lower respectively. In addition, for the hot working steps repeatedly performed after the first heat treatment step [Step 4], the heating temperature is set in the range of 650 °C or higher and 850 °C or lower respectively, and heating is performed so as to reach the heating temperature within 15 seconds from room temperature, and the temperature holding time at the heating temperature is set in the range of 1 second or longer and 40 seconds or shorter.

[0087] (i) Casting step [Step 1]

[0088] The casting step [Step 1] is a step of melting a copper alloy raw material having the above alloy composition using a high-frequency melting furnace in an inert gas atmosphere or in a vacuum and then casting it to form an ingot of a specific shape (for example, a thickness of 30 mm to 300 mm, a width of 500 mm, and a length of 3000 mm). In addition, the alloy composition of the copper alloy raw material may not be exactly the same as the alloy composition of the copper alloy sheet to be manufactured due to the adhesion or volatilization of the added components in the melting furnace during each manufacturing step, but still has an alloy composition substantially the same as that of the copper alloy material.

[0089] (ii) Homogenization heat treatment step [Step 2]

[0090] The homogenization heat treatment step [Step 2] is a step of performing heat treatment for homogenization on the ingot after the casting step [Step 1] is performed. Here, from the viewpoint of suppressing the coarsening of grains, the heat treatment conditions in the homogenization heat treatment step [Step 2] are preferably such that the heating temperature is set in the range of 750 °C or higher and 900 °C or lower, and the holding time is set in the range of 10 minutes or longer and 10 hours or shorter.

[0091] (iii) Hot working step [Step 3]

[0092] The hot working step [Step 3] is the following step: For an ingot that has undergone homogenization heat treatment, hot rolling, wire drawing, and other stretching processes are performed under heating until it reaches a specific thickness to produce a hot-rolled material. The conditions of the hot working step [Step 3] are preferably in the range of a heating temperature of 700 °C or higher and 850 °C or lower, and may be the same as the heating temperature in the homogenization heat treatment step [Step 2]. In addition, the processing rate in the hot working step [Step 3] is preferably 50% or higher.

[0093] Here, the "processing rate" is a value obtained by subtracting the cross-sectional area after processing from the cross-sectional area before stretching processes such as hot rolling and wire drawing, dividing the result by the cross-sectional area before processing, and multiplying by 100 to express it as a percentage, and can be represented by the following formula.

[0094] [Processing rate] (%) = {([Cross-sectional area before processing] - [Cross-sectional area after processing]) / [Cross-sectional area before processing]} × 100

[0095] The hot-rolled material of the hot working step [Step 3] is preferably cooled. Here, from the viewpoint of being able to easily obtain a fine and uniform crystal structure with an average crystal grain diameter of 50 μm or less, the means of cooling the hot-rolled material is preferably the means of water cooling. On the other hand, although crystal grain growth can occur by making the cooling rate after the hot working step slow, it is difficult to uniformly maintain the temperature of the entire hot-rolled material. As a result, it is difficult to obtain a uniform structure and it is not preferred.

[0096] (iv) First heat treatment step [Step 4]

[0097] Next, by performing the first heat treatment step [Step 4] on the water-cooled hot-rolled material, the adjustment of the average crystal grain diameter is carried out. Here, it is set as the following step: Heat treatment is performed at a temperature of 650 °C or higher and 850 °C or lower for 2 hours or more and 5 hours or less, thereby adjusting the average crystal grain diameter to exceed 100 μm. Using a heat treatment furnace, by creating a uniform structure with an average crystal grain diameter exceeding 100 μm, the development of the aggregated structure formed by subsequent processing is hindered, so the maximum value of the orientation density can be reduced.

[0098] Here, it is possible to perform surface cutting on the hot-rolled material after the first heat treatment step [Step 4] has been performed. By performing surface cutting, the surface oxide film and defects generated in the hot working step [Step 3] can be removed. The conditions for surface cutting can be the generally practiced conditions and are not particularly limited. The amount removed from the surface of the hot-rolled material by surface cutting can be appropriately set based on the conditions of the hot working step [Step 3], for example, it can be set to about 0.5 mm to 4 mm from the surface of the hot-rolled material.

[0099] (v) Repeated cold working steps and heat treatment steps

[0100] For the hot-rolled material after the first heat treatment step [step 4] has been carried out, the cold working steps and heat treatment steps are repeatedly carried out more than 2 times until the thickness and dimensions of the product are reached. The cold working steps are stretching processes such as rolling and wire drawing carried out under cooling, and the heat treatment steps are heat treatment. More specifically, for the hot-rolled material after the first heat treatment step [step 4] has been carried out after hot working, at least the first cold working step, the first heat treatment step, the second cold working step and the second heat treatment step are carried out, and the cold working steps and heat treatment steps at this time can be sequentially set as the first cold working step [step 5], the second heat treatment step [step 6], the second cold working step [step 7] and the third heat treatment step [step 8]. Further, for the cold-rolled material after the third heat treatment step [step 8] has been carried out, the third cold working step and heat treatment step can be carried out, and the cold working step and heat treatment step at this time can be respectively set as the third cold working step [step 9] and the fourth heat treatment step [step 10]. Further, for the cold-rolled material after the fourth heat treatment step [step 10] has been carried out, the fourth cold working step and heat treatment step can be carried out, and the cold working step and heat treatment step at this time can be respectively set as the fourth cold working step [step 11] and the fifth heat treatment step [step 12]. By operating in this way, the cold working steps and heat treatment steps are repeatedly carried out more than 2 times on the hot-rolled material after the first heat treatment step [step 4] has been carried out, whereby when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2), the maximum values of the orientation densities at φ1 = 0 to 90°, Φ = 0 to 90° and φ2 being 15°, 20° and 25° are reduced, and thus the chipping of the punching surface generated during stamping can be reduced.

[0101] At this time, the total processing rates in the first cold working step [step 5], the second cold working step [step 7], the third cold working step [step 9], and the fourth cold working step [step 11] are each set in the range of 40% or more and 65% or less. Here, when the cold working steps after the second cold working step [step 7] are not performed and when the total processing rate in at least any one of the first cold working step [step 5], the second cold working step [step 7], the third cold working step [step 9], and the fourth cold working step [step 11] is less than 40%, recrystallization becomes difficult to occur, and thus it is difficult to obtain a uniform structure. In addition, if the total processing rate in at least any one of the first cold working step [step 5], the second cold working step [step 7], the third cold working step [step 9], and the fourth cold working step [step 11] exceeds 65%, the maximum value of the orientation density when the orientation distribution function (ODF) is represented by Euler angles (φ1, Φ, φ2) at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° becomes unnecessarily large. Particularly preferably, the total processing rates in the first cold working step [step 5], the second cold working step [step 7], the third cold working step [step 9], and the fourth cold working step [step 11] are each 60% or less.

[0102] In addition, the heat treatment conditions in the second heat treatment step [step 6], the third heat treatment step [step 8], the fourth heat treatment step [step 10], and the fifth heat treatment step [step 12] are preferably such that the heating temperature is set in the range of 650°C or more and 850°C or less, and heating is performed so as to reach the heating temperature within 15 seconds from room temperature, and the temperature holding time at the heating temperature is set in the range of 1 second or more and 40 seconds or less. Here, if the time for performing the heat treatment exceeds 1 minute, the standard deviation of the crystal grain size may become large. Therefore, from the viewpoint of adjusting the crystal grain size to an appropriate range and obtaining a uniform crystal structure, it is preferable to shorten the time to reach the heating temperature and also shorten the temperature holding time at the heating temperature.

[0103] [6] Use of the copper alloy material

[0104] The copper alloy material of the present invention is extremely useful as a resistor material for resistors, such as shunt resistors or chip resistors. That is, the resistor material for resistors is preferably composed of the above-described copper alloy material. In addition, resistors such as shunt resistors or chip resistors preferably have a resistor material for resistors composed of the above-described copper alloy material.

[0105] The above has described the embodiments of the present invention. However, the present invention is not limited to the above embodiments and also includes all aspects within the concept of the present invention and the scope of the patent application of the invention, and various changes can be made within the scope of the present invention.

[0106] [Examples]

[0107] 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.

[0108] (Examples 1 to 17 of the present invention and Comparative Examples 1 to 6)

[0109] The casting step [1] is carried out to obtain an ingot with a thickness of 30 mm. A copper alloy raw material having the alloy composition shown in Table 1 is melted, and then it is cooled from the molten metal to carry out casting. Here, the alloy composition of Comparative Example 1 is the same as the copper alloy described in the embodiments of Patent Document 1 and Patent Document 2 above.

[0110] For this ingot, the homogenization heat treatment step [Step 2] is carried out. The heat treatment is carried out at a heating temperature of 800°C and a holding time of 5 hours. Next, after the hot working step [Step 3], it is cooled to room temperature by water cooling to obtain a hot-rolled material. The hot working step [Step 3] is carried out at a heating temperature of 800°C and rolled along the length direction until the total processing rate becomes 67% (the thickness before processing is 30 mm, and the thickness after processing is 10 mm).

[0111] For Examples 1 to 17 of the present invention and Comparative Examples 1, 3 to 6, the first heat treatment step [Step 4] is carried out on the hot-rolled material after water cooling to grow the grains. The first heat treatment step [Step 4] is carried out at a heating temperature of 800°C and a holding time of 4 hours. On the other hand, in Comparative Example 2, the first heat treatment step [Step 4] is not carried out on the hot-rolled material after water cooling.

[0112] Next, in order to remove the oxide film formed on the surface, surface cutting of 1 mm is carried out from both sides. The thickness of the hot-rolled material after surface cutting is 8 mm.

[0113] For the hot-rolled material after the hot working step [Step 3], the first cold working step [Step 5] is carried out, which is rolled along the length direction until the total processing rate becomes 62.5% (the thickness before processing is 8 mm, and the thickness after processing is 3 mm). Next, the second heat treatment step [Step 6] is carried out on the cold-rolled material after the first cold working step [Step 5], and the heat treatment is carried out under specific heat treatment conditions.

[0114] Further, for the cold-rolled material after the second heat treatment step [Step 6], the second cold working step [Step 7] is carried out by rolling along the length direction at the total reduction rate shown in Table 2. Next, for the cold-rolled material after the second cold working step [Step 7], the third heat treatment step [Step 8] is carried out by performing heat treatment under the heat treatment conditions shown in Table 2.

[0115] In addition, for the cold-rolled material after the third heat treatment step [Step 8], the third cold working step [Step 9] is carried out by rolling along the length direction at the total reduction rate shown in Table 2. Next, for the cold-rolled material after the third cold working step [Step 9], the fourth heat treatment step [Step 10] is carried out by performing heat treatment under the heat treatment conditions shown in Table 2.

[0116] In addition, for the cold-rolled materials of Invention Examples 1 to 17 and Comparative Examples 2 to 6 of the present invention, after the fourth heat treatment step [Step 10], the fourth cold working step [Step 11] is carried out by rolling along the length direction at the total reduction rate shown in Table 2. Next, for the cold-rolled material after the fourth cold working step [Step 11], the fifth heat treatment step [Step 12] is carried out by performing heat treatment under the heat treatment conditions shown in Table 2. On the other hand, for Comparative Example 1, after the fourth heat treatment step [Step 10], the fifth heat treatment step [Step 12] is carried out without performing the fourth cold working step [Step 11]. In addition, for Comparative Example 6, in the fifth heat treatment step [Step 12], the time until reaching the heating temperature is set to 600 seconds. By operating in this way, the copper alloy materials (copper alloy sheets) of Invention Examples 1 to 17 and Comparative Examples 1 to 6 of the present invention are produced.

[0117] In addition, in Table 1, a horizontal line "-" is described in the column of the components not contained in the alloy composition of the copper alloy raw material, clearly indicating that the component is not contained or even if the component is contained, it is still less than the detection limit value.

[0118] [Various measurement and evaluation methods]

[0119] Using the copper alloy materials (copper alloy sheets) of the above Invention Examples and Comparative Examples of the present invention, the following characteristic evaluations are carried out. The evaluation conditions for each characteristic are as follows.

[0120] [1] When representing the orientation distribution function (ODF) by Euler angles, measurement of the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25°

[0121] For the copper alloy sheets obtained in the examples and comparative examples of the present invention, after mirror-polishing a cross-section parallel to the rolling direction (elongation direction) to prepare a cross-sectional specimen, field emission scanning electron microscopy (FE-SEM) was used for observation to perform EBSD measurement (measurement by electron backscatter diffraction), thereby obtaining crystal orientation analysis data by the SEM-EBSD method. Here, in the EBSD measurement, the area to be measured was set to 0.2 mm 2 , and the step size during measurement could be set to 0.5 μm. Based on the measurement results obtained from this EBSD measurement, using "OIM ANALYSIS" as data analysis software, and using the harmonic series expansion, the series rank was set to 16, and the half-width when fitting the Gaussian distribution was set to 5° to perform intensity calculation, and the option of Enforce Orthotropic Sample Symmetry was set for the obtained calculation results to perform texture analysis, thereby plotting an ODF map showing the intensity distribution of crystal orientations represented by Euler angles (φ1, Φ, φ2). For the conditions when φ2 was set to 15°, 20°, and 25° respectively, in a graph showing the orientation density in the range of φ1 = 0 to 90° and Φ = 0 to 90° with φ1 as the horizontal axis and Φ as the vertical axis, the intensity distribution of crystal orientations was shown, thereby obtaining the maximum value of the orientation density when φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 was 15°, 20°, and 25°.

[0122] [2] Average crystal grain size and its standard deviation of the copper alloy material

[0123] The average crystal grain size and its standard deviation of the copper alloy material were obtained from the crystal orientation analysis data of the above SEM-EBSD method, that is, from the Grain Size (diameter) graph obtained by using "OIM ANALYSIS" as data analysis software. At this time, the average diameter and standard deviation obtained from the Area Fraction could be set as the average crystal grain size and its standard deviation of the crystal grains. The results are shown in Table 1.

[0124] [3] Evaluation method for the size of gouges generated in the copper alloy material during stamping

[0125] In order to evaluate the size of chipping generated during stamping of the fabricated copper alloy material, a shear test described in the shear test method for copper and copper alloy thin strips specified in the Technical Standard JCBA T310:2019 of the Japan Copper Development Association is performed. That is, the die is adjusted so that the clearance between the upper die (punch) and the lower die (die) is in the range of 20 μm or more and 30 μm or less, and adjusted so that the ratio of the fracture surface to the cut surface is in the range of 30% or more and 50% or less. The copper alloy material is subjected to stamping to form a square shape, and a test material of the copper alloy material with a cut surface on the outer edge is fabricated. The size of the square along the extension direction is 10 mm, and the size along the sheet width direction intersecting the extension direction at a right angle is 10 mm.

[0126] Figure 1 It is a schematic diagram showing the state of the stamped copper alloy material viewed from a direction parallel to the cut surface in order to make the contour shape (right edge part) of the cut surface recognizable when stamping the copper alloy material of the present invention. Figure 1 In it, the contour shape of the cut surface 2 shown schematically in a plane is shown. The plane includes the direction X perpendicular to the cut surface 2 and the thickness direction Y. Figure 1 The copper alloy material 1 shown has a cut surface 2 after being subjected to stamping. The stamping is performed by lowering the upper die (punch) while being fixed to a lower die (die) not shown. Here, the cut surface 2 is formed with a corner break 3, a shear surface 4, and a fracture surface 5 in order from the top surface 1a side of the copper alloy material 1 after being stamped. Here, since the fracture surface 5 is in a chipped shape with respect to the shear surface 4, chipping 6 is mostly formed at the cut surface 2 which is the punching surface. In addition, at the lower edge of the cut surface 2, a burr 7 is mostly formed so as to extend outward from the fracture surface 5.

[0127] In this embodiment, in order to make the contour shape (right edge part) of the cut surface 2 recognizable when stamping the copper alloy materials 1 of the present invention example and the comparative example, for the test material composed of the stamped copper alloy material 1, an optical microscope (manufactured by Olympus Corporation, model: GX71) is used and observation is performed at a magnification of 300 times from a direction parallel to the cut surface 2. Then, for the scanning electron microscope (SEM) photograph, as Figure 1 shown, parallel to the plate surface of the copper alloy material from the tip of the burr 7 (along Figure 1An imaginary line drawn in the direction X), and a boundary line 8 drawn at a position considered to be the boundary between the shear plane 4 and the fracture plane 5 are set as opposite sides, and the vertices of these opposite sides are connected to each other by a pair of opposite sides drawn in the thickness direction Y, thereby forming an imaginary rectangle R with four sides. At this time, the ratio of the area of the copper alloy material 1 to the area divided by this rectangle R is calculated as a percentage (%).

[0128] Regarding the ratio of the area of the overlapping portion 9 of the copper alloy material 1 and the rectangle R to the area of the calculated rectangle R, when it is 42% or more, it is evaluated as "◎" because the chipping 6 formed on the cut surface 2 as the punching surface is sufficiently small. In addition, when the ratio of the area of the overlapping portion 9 of the copper alloy material 1 and the rectangle R to the area of the rectangle R is 30% or more and less than 42%, it is evaluated as "〇" because the chipping 6 on the punching surface is small. On the other hand, when the ratio of the area of the overlapping portion 9 of the copper alloy material 1 and the rectangle R to the area of the rectangle R is less than 30%, it is evaluated as "×" because the size of the chipping 6 on the punching surface is not in the appropriate range. The results are shown in Table 3.

[0129] [4] Measurement of volume resistivity

[0130] For the manufactured copper alloy material, a test material is prepared by cutting a plate having a thickness of 0.3 mm into a width of 10 mm and a length of 300 mm.

[0131] The volume resistivity ρ is measured by the four-terminal method according to the method specified in Japanese Industrial Standard JIS C2525 at room temperature of 20 °C, with the distance between the voltage terminals set to 200 mm and the measurement current set to 100 mA, and the voltage is measured and the volume resistivity ρ [μΩ·cm] is obtained from the measured value.

[0132] Regarding the measured volume resistivity ρ, when it is 80 μΩ·cm or more, it is regarded as having a sufficiently large volume resistivity ρ and being excellent as a resistance material, and is evaluated as "◎". In addition, when the volume resistivity ρ is 70 μΩ·cm or more and less than 80 μΩ·cm, it is regarded as having a large volume resistivity ρ and being good as a resistance material, and is evaluated as "〇". On the other hand, when the volume resistivity ρ is less than 70 μΩ·cm, it is regarded as having a small volume resistivity ρ and being poor as a resistance material, and is evaluated as "×". In this example, "◎" and "〇" are evaluated as the qualified grades. The results are shown in Table 3.

[0133] [5] Measurement method of thermoelectric emf (EMF) against copper

[0134] For the produced copper alloy material, a sheet with a thickness of 0.3 mm obtained is cut into a width of 10 mm and a length of 1000 mm to produce a test material.

[0135] The measurement of the thermal electromotive force (EMF) of the test material with respect to copper is carried out in accordance with Japanese Industrial Standard JIS C2527. More specifically, as Figure 2 shown, for the measurement of the thermal electromotive force (EMF) of the test material 11 with respect to copper, a pure copper wire with a diameter of 1 mm that has been fully annealed is used as the standard copper wire 21. The temperature measurement contact point P1 where one end of the test material 11 and the standard copper wire 21 are connected is immersed in warm water that has been kept warm in a constant temperature bath 41 at 80 °C, and the reference contact points P21 and P22 where the other ends of the test material 11 and the standard copper wire 21 are respectively connected to copper wires 31 and 32 are immersed in ice water at 0 °C that has been kept cold in a freezing point device 42. Then, a voltage measuring device 43 is used to measure the electromotive force at this time. For the obtained electromotive force, it is divided by the temperature difference, that is, 80 [°C], to obtain the thermal electromotive force (EMF) (μV / °C) with respect to copper.

[0136] Regarding the measured thermal electromotive force (EMF) with respect to copper, when the absolute value is 0.5 μV / °C or less, it is regarded as having a sufficiently small absolute value of the thermal electromotive force (EMF) and being good as a resistance material, and is evaluated as "◎". In addition, when the absolute value is greater than 0.5 μV / °C and 1.0 μV / °C or less, it is regarded as having a small absolute value of the thermal electromotive force (EMF) and being good as a resistance material, and is evaluated as "○". On the other hand, when the absolute value of the thermal electromotive force (EMF) is greater than 1.0 μV / °C, it is regarded as having a large absolute value of the thermal electromotive force (EMF) and being poor as a resistance material, and is evaluated as "×". The results are shown in Table 3.

[0137] [6] Method for measuring the resistance temperature coefficient (TCR)

[0138] For the produced copper alloy material, a sheet with a thickness of 0.3 mm obtained is cut into a width of 10 mm and a length of 300 mm to produce a test material.

[0139] The measurement of the resistance temperature coefficient (TCR) is carried out by setting the distance between the voltage terminals to 200 mm and the measurement current to 100 mA. By the four-terminal method according to the methods specified in Japanese Industrial Standards JIS C2525 and JIS C2526, the voltage when the test material is heated to 150 °C is measured, and the resistance value R 150℃ [μΩ] at 150 °C is obtained from the obtained value. Next, the voltage when the test material is cooled to 20 °C is measured, and the resistance value R 20℃[μΩ]. And, based on R which is the obtained resistance value 150℃ and R 20℃ of the numerical values, according to the formula TCR = {(R 150℃ [μΩ] - R 20℃ [μΩ]) / R 20℃ [μΩ]} × {1 / (150 [°C] - 20 [°C])} × 10 6 , the resistance temperature coefficient (ppm / °C) is calculated.

[0140] Regarding the measured resistance temperature coefficient (TCR), the case where the absolute value is less than 50 ppm / °C is regarded as the absolute value of the resistance temperature coefficient (TCR) being sufficiently small and the resistance material being excellent, and is evaluated as "◎". In addition, the case where the absolute value of the resistance temperature coefficient (TCR) is 50 ppm / °C or more and 60 ppm / °C or less is regarded as the absolute value of the resistance temperature coefficient (TCR) being small and the resistance material being good, and is evaluated as "○". On the other hand, the case where the absolute value of the resistance temperature coefficient (TCR) is greater than 60 ppm / °C is regarded as the absolute value of the resistance temperature coefficient (TCR) being large and the resistance material being poor, and is evaluated as "×". The results are shown in Table 3.

[0141] [7] Evaluation of reliability

[0142] Furthermore, in order to investigate the reliability when the copper alloy material is used as a resistance material for a long time for Examples 1 to 17 and Comparative Examples 1 to 6 of the present invention, especially the stability of electrical characteristics such as heat, for the test materials after measuring the volume resistivity in the measurement of the volume resistivity in the above [4], heating is carried out at 400 °C for 2 hours, thereby performing an accelerated test for the stability of electrical characteristics against heat. After the accelerated test by heating, using the same method as the measurement of the volume resistivity in the above [4], the volume resistivity of the test material is measured, and then the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating is calculated respectively. Here, the case where the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating is 1.0 μΩ·cm or less is regarded as the reduction in volume resistivity due to heating being small and the reliability being excellent, and is evaluated as "◎". In addition, the case where the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating exceeds 1.0 μΩ·cm is regarded as the reduction in volume resistivity due to heating being large and relatively not good from the perspective of reliability, and is evaluated as "○". The results are shown in Table 3.

[0143] [8] Comprehensive evaluation

[0144] Among these evaluation results, when evaluating the size of chipping generated in the copper alloy material during stamping, the volume resistivity ρ, the thermoelectromotive force (EMF) against copper, and the temperature coefficient of resistance (TCR), the case where all four characteristics are evaluated as "◎" is regarded as excellent in these four characteristics, namely, the size of chipping generated in the copper alloy material during stamping, the volume resistivity ρ, the thermoelectromotive force (EMF) against copper, and the temperature coefficient of resistance (TCR), and is evaluated as "◎". In addition, the case where at least one of these four evaluation results is evaluated as "○" and the rest are evaluated as "◎" is regarded as at least good in these four characteristics and is evaluated as "○". On the other hand, the case where at least one of the evaluation results of stamping processability, volume resistivity ρ, thermoelectromotive force (EMF) against copper, and temperature coefficient of resistance (TCR) is "×" is regarded as at least one of these four characteristics being unqualified and is evaluated as "×". The results are shown in Table 3.

[0145] [Table 1]

[0146]

[0147] [Table 2]

[0148]

[0149] [Table 3]

[0150]

[0151] Based on the results of Tables 1 to 3, for the copper alloy materials of Examples 1 to 17 of the present invention, the maximum values of the alloy composition and the orientation density are within the appropriate range of the present invention, and the ratios of the areas of the portions 9 where the copper alloy material 1 overlaps with the rectangle R to the area of the rectangle R are all evaluated as "◎" or "○", so it is evaluated that the chipping formed on the punching surface is small. In addition, the copper alloy materials of Examples 1 to 17 of the present invention are also all evaluated as "◎" or "○" in terms of volume resistivity ρ, thermoelectromotive force (EMF) against copper, and temperature coefficient of resistance (TCR).

[0152] On the other hand, for the copper alloy materials of Comparative Examples 1 and 2, when expressing the orientation distribution function (ODF) in terms of Euler angles, the maximum values of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° are large and outside the appropriate range of the present invention. Therefore, the copper alloy materials of Comparative Examples 1 and 2 are evaluated as "×" in terms of the size of chipping generated in the copper alloy material during stamping.

[0153] In addition, for the copper alloy material of Comparative Example 3, the content of Ni is low and the alloy composition is outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 3 is evaluated as "×" in terms of the thermoelectromotive force (EMF) against copper.

[0154] In addition, in the copper alloy material of Comparative Example 4, the contents of Mn and Ni are both small and the alloy composition is outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 4 was evaluated as "×" in terms of volume resistivity ρ. In particular, the copper alloy material of Comparative Example 4 was evaluated as "×" in terms of volume resistivity ρ because of the small content of Mn.

[0155] In addition, in the copper alloy material of Comparative Example 5, the content of Mn is large and the alloy composition is outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 5 was evaluated as "×" in terms of the thermal electromotive force (EMF) against copper.

[0156] In addition, in the copper alloy material of Comparative Example 6, the content of Ni is relatively large and the alloy composition is outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 6 was evaluated as "×" in terms of the thermal electromotive force (EMF) against copper and the resistance temperature coefficient (TCR).

[0157] Based on these results, it was confirmed that: when the alloy composition of the copper alloy material of the present invention and the maximum value of the orientation density of the orientation distribution function (ODF) expressed by the Euler angles (φ1, Φ, φ2) are within the appropriate range of the present invention, the chipping of the copper alloy material generated during stamping is small. At the same time, it was also confirmed that: the copper alloy material of the example of the present invention is at least good in terms of volume resistivity ρ, the thermal electromotive force (EMF) against copper, and the resistance temperature coefficient (TCR).

[0158] In addition, Figure 3 The following is a chart showing the orientation density in the range of φ1 = 0 to 90° and Φ = 0 to 90° when the orientation distribution function (ODF) of the copper alloy material of Example 14 of the present invention is expressed by the Euler angles (φ1, Φ, φ2) with φ1 as the horizontal axis and Φ as the vertical axis. Figure 3 (a) is a chart when φ2 = 15°, Figure 3 (b) is a chart when φ2 = 20°, Figure 3 (c) is a chart when φ2 = 25°. Based on this chart, it can be seen that the maximum value of the orientation density of the copper alloy material of Example 14 of the present invention at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is 3.1 (the measured value of the maximum value of the orientation density is the value obtained by rounding the second decimal place).

[0159] In addition, Figure 4 A scanning electron microscope (SEM) photograph is shown to make the contour shape (right edge part) of the cut surface recognizable when stamping is applied to the copper alloy materials of the examples and comparative examples of the present invention, and Figure 1 similarly, a photograph when observing the punched copper alloy material in a direction parallel to the cut surface. Here, Figure 4(a) is an SEM photograph of the contour shape of the cut surface of the copper alloy material of Example 5 of the present invention. Figure 4 (b) is an SEM photograph of the contour shape of the cut surface of the copper alloy material of Comparative Example 1. From these SEM photographs, it was confirmed that the chipping of the fracture surface generated during stamping of the copper alloy material of the present invention example is smaller than that of the copper alloy material of the comparative example.

[0160] Furthermore, it was found that: compared with Examples 5, 8, and 12 of the present invention in which the Fe content is 0.30% by mass or more and the evaluation result of reliability is evaluated as "○", in Examples 1 to 4, 6, 7, 9 to 11, and 13 to 17 of the present invention, by setting the Fe content to 0.20% by mass or less, the stability of the electrical characteristics such as heat is improved, and thus the evaluation result of reliability is evaluated as "◎".

[0161] In addition, it was also found that: compared with Examples 1 to 3 of the present invention in which the evaluation result of the resistance temperature coefficient (TCR) is evaluated as "○", Examples 4 to 17 of the present invention contain one or both of Fe and Co, and the absolute value of the resistance temperature coefficient (TCR) is small, so the evaluation result of the resistance temperature coefficient (TCR) is evaluated as "◎".

[0162] Reference numerals

[0163] 1: Copper alloy material

[0164] 1a: Top surface of the copper alloy material

[0165] 1b: Bottom surface of the copper alloy material

[0166] 2: Cut surface

[0167] 3: Corner break

[0168] 4: Shear surface

[0169] 5: Fracture surface

[0170] 6: Chipping of the punching surface

[0171] 7: Burr

[0172] 8: Boundary line

[0173] 9: Portion where the rectangle overlaps the copper alloy material

[0174] 11: Test material

[0175] 21: Standard copper wire

[0176] 31, 32: Copper wire

[0177] 41: Constant temperature bath

[0178] 42: Ice point device

[0179] 43: Voltage detector

[0180] P1: Temperature measurement contact point

[0181] P 21 ,P 22 : Reference contact point

[0182] X: Direction perpendicular to the cut surface

[0183] Y: Thickness direction

Claims

1. A copper alloy material having the following alloy composition: containing Mn of 20.0% by mass or more and 35.0% by mass or less and Ni of 6.5% by mass or more and 17.0% by mass or less, the balance being composed of Cu and unavoidable impurities, when representing the orientation distribution function (ODF) obtained by crystal orientation analysis by the SEM-EBSD method in a longitudinal section including the elongation direction and the thickness direction of the copper alloy material by Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 being 15°, 20°, and 25° is 6.0 or less.

2. The copper alloy material according to claim 1, wherein, In the aforementioned longitudinal section, the average crystal grain size of the crystal grains obtained from the crystal orientation analysis data by the SEM-EBSD method is 20 μm or less and the standard deviation of the average crystal grain size is 10 μm or less.

3. The copper alloy material according to claim 1, wherein, The aforementioned alloy composition further contains one or both of Fe of 0.01% by mass or more and 0.50% by mass or less and Co of 0.01% by mass or more and 2.00% by mass or less.

4. The copper alloy material according to claim 1, wherein, The aforementioned alloy composition further contains at least one selected from the group consisting of the following components: Sn of 0.01% by mass or more and 5.00% by mass or less, Zn of 0.01% by mass or more and 5.00% by mass or less, Cr of 0.01% by mass or more and 0.50% by mass or less, Ag of 0.01% by mass or more and 0.50% by mass or less, Al of 0.01% by mass or more and 1.00% by mass or less, Mg of 0.01% by mass or more and 0.50% by mass or less, Si of 0.01% by mass or more and 0.50% by mass or less and P of 0.01% by mass or more and 0.50% by mass or less.

5. A resistive material for a resistor, which is composed of the copper alloy material according to any one of claims 1 to 4.

6. A resistor, which is a shunt resistor or a chip resistor, and the resistor has the resistive material for a resistor according to claim 5.

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