JP7354481B1 - Copper alloy materials, resistor materials and resistors using copper alloy materials - Google Patents

Abstract

A copper alloy material that has excellent press punching workability, has a sufficiently high volume resistivity, and has a small absolute value of thermal electromotive force (EMF) against copper, and a resistance material for resistors using the copper alloy material. and resistors. The copper alloy material contains Mn: 20.0 mass% or more and 35.0 mass% or less and Ni: 6.5 mass% or more and 17.0 mass% or less, and O: 0 mass ppm or more and 800 mass ppm or less, and C: has an alloy composition of 0 mass ppm or more and 800 mass ppm or less, and contains O and C in a total of 60 mass ppm or more and 800 mass ppm or less, and the balance is Cu and inevitable impurities.

Description

The present invention relates to a copper alloy material, a resistance material for a resistor, and a resistor using the copper alloy material.

Metal materials used in resistors are required to have a stable resistance value even when the environmental temperature changes. In this regard, Cu--Mn--Ni alloys and Cu--Mn--Sn alloys are widely used as alloy materials constituting resistive materials because their resistance values do not easily change even when the environmental temperature changes.

However, these Cu-Mn-Ni alloys and Cu-Mn-Sn alloys are used as resistance materials in resistors that are designed to have a predetermined resistance value by forming a circuit (pattern) using resistance materials. When used as a resistor, the volume resistivity is as small as less than 50×10 ⁻⁸ (Ω·m), so it is necessary to increase the resistance value of the resistor by decreasing the cross-sectional area of the resistive material. In such resistors, when a large current is temporarily passed through the circuit, or when a certain amount of large current continues to be passed through the circuit, the Joule heat generated in the resistive material with a small cross section increases and generates heat. As a result, there was a problem that the resistance material was easily broken (fused) due to heat.

Therefore, in order to suppress the reduction in the cross-sectional area of the resistive material, a resistive material with a higher volume resistivity is required.

For example, Patent Document 1 describes that in a copper alloy containing Mn in a range of 23% by mass or more and 28% by mass or less, and containing Ni in a range of 9% by mass or more and 13% by mass or less, the mass fraction of Mn and By configuring the mass fraction of Ni so that the thermoelectromotive force against copper is smaller than ± ¹ μV/°C at 20°C, a high electrical resistance (volume resistivity ρ ), the thermal electromotive force against copper (thermal electromotive force against copper, EMF) is small, the temperature coefficient of electrical resistance is low, and the specific electrical resistance has high stability over time (time invariance). It is said that it is possible to obtain a copper alloy with

Further, Patent Document 2 describes a copper alloy containing Mn in a range of 21.0% by mass or more and 30.2% by mass or less, and containing Ni in a range of 8.2% by mass or more and 11.0% by mass or less. , the temperature coefficient of resistance (TCR) value x [ppm/°C] in the temperature range from 20°C to 60°C is in the range of -10≦x≦-2 or 2≦x≦10, and the volume resistivity ρ By setting 80×10 ^-8 [Ω・m] to 115×10 ⁻⁸ [Ω・m] or less, the cross-sectional area of resistor circuits such as chip resistors using resistance materials can be reduced. It is said that it is possible to suppress the increase in Joule heat of the resistance material.

Special table 2016-528376 publication JP 2017-053015 Publication

2. Description of the Related Art As electric and electronic components have become smaller and more highly integrated in recent years, resistors and the resistance materials used therein have also become smaller. Resistance materials used in resistors are generally formed by cutting processes such as press punching, so in order to reduce variations in resistance values, copper alloy materials must have excellent press punching properties. is required. Here, in order to provide excellent press punching workability to a copper alloy material, it is necessary to improve the dimensional accuracy of the cut surface during press punching.

Furthermore, in recent years, resistors such as shunt resistors and chip resistors have been required to have high volume resistivity ρ as well as high precision resistors that can withstand high-temperature usage environments in the electrical systems of electric vehicles. The copper alloy used in such resistors is also required to be highly accurate and can withstand high-temperature usage environments. More specifically, there is a need for a copper alloy material that has a large volume resistivity ρ, is difficult to generate electromotive force with copper even at high temperatures, and has a small absolute value of thermoelectromotive force (EMF) with respect to copper.

Therefore, an object of the present invention is to provide a copper alloy material that has excellent press punching workability, has a sufficiently high volume resistivity, and has a small absolute value of thermoelectromotive force (EMF) with respect to copper, and the copper alloy material. An object of the present invention is to provide a resistance material for a resistor using the material and a resistor.

The present inventors have determined that the present invention contains Mn: 20.0 mass% or more and 35.0 mass% or less and Ni: 6.5 mass% or more and 17.0 mass% or less, and O: 0 mass ppm or more and 800 mass ppm or less. and C: 0 mass ppm or more and 800 mass ppm or less, and the total content of O and C is 60 mass ppm or more and 800 mass ppm or less, and the balance is Cu and unavoidable impurities. For example, it has a sufficiently high volume resistivity ρ as a resistive material, and also has a small absolute value of thermoelectromotive force (EMF) against copper in the temperature range from room temperature (for example, 5°C to 35°C) to high temperature (for example, 80°C). The present inventors have discovered that a copper alloy material with excellent press punching workability can be obtained, and have completed the present invention.

In order to achieve the above object, the gist of the present invention is as follows.
(1) Contains Mn: 20.0 mass% or more and 35.0 mass% or less, Ni: 6.5 mass% or more and 17.0 mass% or less, O: 0 mass ppm or more and 800 mass ppm or less, and C: A copper alloy material having an alloy composition of 0 mass ppm or more and 800 mass ppm or less, and containing O and C in a total of 60 mass ppm or more and 800 mass ppm or less, with the balance consisting of Cu and inevitable impurities.
(2) Among the precipitated particles containing at least one of oxides and carbides observed within a viewing area of 10,000 μm ² when viewed in a cross section perpendicular to the stretching direction during processing of the copper alloy material, the largest The copper alloy material according to (1) above, wherein the number of coarse precipitated particles having a size of more than 20 μm is 3 or less.
(3) The alloy composition is Fe: 0.01% by mass or more and 0.50% by mass or less, Co: 0.01% by mass or more and 2.00% by mass or less, Sn: 0.01% by mass or more and 5.00% by mass. % or less, Zn: 0.01 mass% or more and 5.00 mass% or less, Cr: 0.01 mass% or more and 0.50 mass% or less, Ag: 0.01 mass% or more and 0.50 mass% or less, Al: 0.01 mass% or more and 1.00 mass% or less, Mg: 0.01 mass% or more and 0.50 mass% or less, Si: 0.01 mass% or more and 0.50 mass% or less, and P: 0.01 mass% The copper alloy material according to (1) or (2) above, further containing at least one component selected from the group consisting of % or more and 0.50% or less by mass.
(4) A resistance material for a resistor, comprising the copper alloy material according to any one of (1) to (3) above.
(5) A resistor comprising the resistor material according to (4) above.

According to the present invention, a copper alloy material has excellent press punching workability, has a sufficiently high volume resistivity, and has a small absolute value of thermoelectromotive force (EMF) against copper, and the copper alloy material. A resistive material for a resistor and a resistor using the present invention can be provided.

FIG. 2 is a schematic diagram showing a cut surface when press punching is performed on the copper alloy material of the present invention. FIG. 2 is a schematic diagram of an apparatus for measuring thermoelectromotive force (EMF) against copper for test materials of inventive examples and comparative examples. An example of an optical micrograph of a cross section perpendicular to the stretching direction during processing of the copper alloy material of Inventive Example 9 observed within a viewing area of 10000 μm ² is shown. A scanning electron microscope (SEM) photograph is shown of a cross section including the thickness direction and the width direction of a cut surface obtained by press punching the copper alloy material of Inventive Example 11. A scanning electron microscope (SEM) photograph of a cut surface obtained by press punching the copper alloy material of Comparative Example 1 is shown in a cross section including the thickness direction and the width direction.

Hereinafter, preferred embodiments of the copper alloy material of the present invention will be described in detail. In addition, in the component composition of the alloy of the present invention, "mass %" may be simply indicated as "%". Moreover, "mass ppm" may be simply indicated as "ppm".

The copper alloy material according to the present invention contains Mn: 20.0 mass% or more and 35.0 mass% or less, Ni: 6.5 mass% or more and 17.0 mass% or less, and O: 0 mass ppm or more and 800 mass% or less. ppm or less and C: 0 mass ppm or more and 800 mass ppm or less, and has an alloy composition containing O and C in a total of 60 mass ppm or more and 800 mass ppm or less, with the balance consisting of Cu and inevitable impurities.

The copper alloy material of the present invention contains Mn in a range of 20.0 mass% to 35.0 mass%, and contains Ni in a range of 6.5 mass% to 17.0 mass%. , the volume resistivity ρ is increased, and the absolute value of the copper thermoelectromotive force (EMF, hereinafter sometimes simply referred to as "copper thermoelectromotive force") generated between 0°C and 80°C temperature environment. Since the resistor becomes smaller, it is possible to improve the performance of the resistor even in a high-temperature environment.

Regarding this, the copper alloys described in Patent Documents 1 and 2 mentioned above have a single phase with a highly ductile face-centered cubic structure, so the dimensional accuracy of the cut surface during press punching is low, and the copper alloys are There was a problem in that the resistance values of the resulting resistors varied.

However, in the copper alloy material according to the present invention, in particular, by containing Mn in a range of 20.0 mass% or more and 35.0 mass% or less, and containing O and C in a total amount of 60 mass ppm or more, O and C By combining one or both of them with Mn to form oxides or carbides, it is possible to increase the ratio of sheared surfaces in the cross section when press punching a copper alloy material. The larger the ratio of the sheared surface, the smaller the area of sagging and fractured surfaces in the cross section, which makes it possible to increase the flatness of the cut surface and improve the processing accuracy in press punching. As a result, it is possible to improve the precision of resistors obtained from copper alloys.

Further, the copper alloy material according to the present invention contains Mn in a range of 20.0% by mass to 35.0% by mass, and contains Ni in a range of 6.5% by mass to 17.0% by mass. In addition, by containing O and C in a total amount of 800 mass ppm or less, it is possible to make the copper alloy material less likely to become embrittled, thereby increasing the strength of the copper alloy material and making it easier to manufacture. .

As a result, by using the copper alloy material according to the present invention, the copper alloy material has excellent press punching workability, has a sufficiently high volume resistivity ρ, and has a small absolute value of thermoelectromotive force (EMF) with respect to copper. It is possible to provide a material, a resistance material for a resistor using the same, and a resistor.

[1] Composition of copper alloy material <Essential ingredients>
The alloy composition of the copper alloy material of the present invention contains Mn: 20.0% by mass or more and 35.0% by mass or less and Ni: 6.5% by mass or more and 17.0% by mass or less as essential components. be.

(Mn: 20.0 mass% or more and 35.0 mass% or less)
Mn (manganese) is an element that increases the volume resistivity ρ. In order to exhibit this effect and obtain a homogeneous copper alloy material, Mn is preferably contained in an amount of 20.0% by mass or more, more preferably 22.0% by mass or more, and 24.0% by mass. % or more is more preferable. Here, by increasing the Mn content to 22.0% by mass or more or 24.0% by mass or more, the volume resistivity ρ of the copper alloy material can be further increased. On the other hand, when the Mn content exceeds 35.0% by mass, the melting point of the copper alloy material decreases, making it difficult to manufacture the copper alloy material, especially controlling hot working, so that uniform properties cannot be obtained. things become difficult. Therefore, the Mn content is set in a range of 20.0% by mass or more and 35.0% by mass or less.

(Ni: 6.5% by mass or more and 17.0% by mass or less)
Ni (nickel) is an element that adjusts the thermoelectromotive force (EMF) against copper in the positive direction. In order to exhibit this effect, it is preferable that Ni be contained in an amount of 6.5% by mass or more. On the other hand, if the Ni content exceeds 17.0% by mass, it becomes difficult to obtain a uniform structure, and the volume resistivity ρ, thermoelectromotive force (EMF) relative to copper, etc. may change. In particular, the Ni content is set in the range of 6.5% by mass or more and 17.0% by mass or less, from the viewpoint of obtaining a copper alloy material with desired characteristics and the viewpoint of obtaining a copper alloy material that is easy to manufacture. The content is preferably in the range of 12.0% by mass or more, and more preferably 6.5% by mass or more and 9.0% by mass or less.

(One or two of O and C: 60 mass ppm or more and 800 mass ppm or less in total)
By forming oxides and carbides with Mn, O (oxygen) and C (carbon) increase the proportion of sheared surfaces in the cross section when press punching copper alloy materials, thereby improving the press punching process. At least one of these elements is essential because it has the effect of improving properties. In order to exhibit this effect, the total content of O and C is preferably 60 mass ppm or more, more preferably 100 mass ppm or more. On the other hand, if the total amount of one or two of O and C exceeds 800 mass ppm, the copper alloy material becomes brittle and difficult to manufacture. Therefore, from the viewpoint of achieving high strength and improving press punching workability, the total content of one or two of O and C is in the range of 60 mass ppm or more and 800 mass ppm or less, preferably 100 mass ppm or more. The range is from 800 ppm by mass to 800 ppm by mass. Moreover, the content of one or two of O and C may be in a range of 60 mass ppm or more and 600 mass ppm or less, or 100 mass ppm or more and 600 mass ppm or less.

(O and C: 0 mass ppm or more and 800 mass ppm or less, respectively)
Here, the content of O is in the range of 0 mass ppm or more and 800 mass ppm or less from the viewpoint of increasing the strength of the copper alloy material without making it brittle. Further, from the same viewpoint, the content of C is also in the range of 0 mass ppm or more and 800 mass ppm or less. One or both of the content of O and the content of C may be in the range of 0 mass ppm or more and 600 mass ppm or less.

<Optional addition ingredients>
The copper alloy material of the present invention includes optionally added components such as Fe: 0.01% by mass or more and 0.50% by mass or less, Co: 0.01% by mass or more and 2.00% by mass or less, and Sn: 0.01% by mass. 5.00 mass% or more, Zn: 0.01 mass% or more and 5.00 mass% or less, Cr: 0.01 mass% or more and 0.50 mass% or less, Ag: 0.01 mass% or more and 0.50 mass% % or less, Al: 0.01 mass% or more and 1.00 mass% or less, Mg: 0.01 mass% or more and 0.50 mass% or less, Si: 0.01 mass% or more and 0.50 mass% or less, and P : It can further contain at least one component selected from the group consisting of 0.01% by mass or more and 0.50% by mass or less.

(Fe: 0.01% by mass or more and 0.50% by mass or less)
Fe (iron) is an element that adjusts thermoelectromotive force (EMF) against copper in a positive direction. In order to exhibit this effect, it is preferable that Fe is contained in an amount of 0.01% by mass or more. On the other hand, if the Fe content exceeds 0.50% by mass, it becomes difficult to obtain a uniform structure, which tends to cause variations in electrical performance. Therefore, the content of Fe is preferably in the range of 0.01% by mass or more and 0.50% by mass or less.

(Co: 0.01% by mass or more and 2.00% by mass or less)
Co (cobalt) is an element that adjusts thermoelectromotive force (EMF) against copper in a positive direction. In order to exhibit this effect, it is preferable that Co is contained in an amount of 0.01% by mass or more. On the other hand, if the Co content exceeds 2.00% by mass, it becomes difficult to obtain a uniform structure, which tends to cause variations in electrical performance. Therefore, the Co content is preferably in the range of 0.01% by mass or more and 2.00% by mass or less.

(Sn: 0.01% by mass or more and 5.00% by mass or less)
Sn (tin) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain Sn at 0.01% by mass or more. On the other hand, by setting the Sn content to 5.00% by mass or less, it is possible to prevent the decrease in manufacturability due to embrittlement of the copper alloy material.

(Zn: 0.01% by mass or more and 5.00% by mass or less)
Zn (zinc) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain Zn in an amount of 0.01% by mass or more. On the other hand, the Zn content should be kept at 5.00% by mass or less because it may have a negative effect on the stability of the resistor's electrical performance, such as volume resistivity ρ and thermoelectromotive force (EMF) against copper. It is preferable to do so.

(Cr: 0.01% by mass or more and 0.50% by mass or less)
Cr (chromium) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain 0.01% by mass or more of Cr. On the other hand, the Cr content should be kept at 0.50% by mass or less because it may have an adverse effect on the stability of the electrical performance of the resistor, such as volume resistivity ρ and thermoelectromotive force (EMF) against copper. It is preferable to do so.

(Ag: 0.01% by mass or more and 0.50% by mass or less)
Silver (Ag) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain 0.01% by mass or more of Ag. On the other hand, since the Ag content may have a negative effect on the stability of the electrical performance of the resistor, such as the volume resistivity ρ and the thermoelectromotive force (EMF) against copper, the Ag content should be kept at 0.50% by mass or less. It is preferable to do so.

(Al: 0.01% by mass or more and 1.00% by mass or less)
Al (aluminum) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain Al at 0.01% by mass or more. On the other hand, since the Al content may cause the copper alloy material to become brittle, it is preferable that the Al content is 1.00% by mass or less.

(Mg: 0.01% by mass or more and 0.50% by mass or less)
Mg (magnesium) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain Mg in an amount of 0.01% by mass or more. On the other hand, since the Mg content may cause the copper alloy material to become brittle, it is preferable that the Mg content is 0.50% by mass or less.

(Si: 0.01% by mass or more and 0.50% by mass or less)
Si (silicon) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain Si in an amount of 0.01% by mass or more. On the other hand, the Si content is preferably 0.50% by mass or less since it may cause the copper alloy material to become brittle.

(P: 0.01% by mass or more and 0.50% by mass or less)
P (phosphorus) is a component that can be used to adjust the volume resistivity ρ. In order to exhibit this effect, it is preferable to contain P at least 0.01% by mass. On the other hand, the P content is preferably 0.50% by mass or less since it may cause the copper alloy material to become brittle.

(Total amount of optionally added components: 0.01% by mass or more and 5.00% by mass or less)
At least one (optional addition) component selected from the group consisting of Fe, Co, Sn, Zn, Cr, Ag, Al, Mg, Si, and P is added in total in order to obtain the effects of the above-mentioned optional addition components. The content is preferably 0.01% by mass or more. On the other hand, the total content of these optionally added components should be 5.00% by mass or less, since if they are included in large amounts, the electrical properties will become unstable and it will be difficult to manufacture the copper alloy material. is preferred.

<Remainder: Cu and inevitable impurities>
Other than the above-mentioned essential components and optionally added components, the remainder consists of Cu (copper) and unavoidable impurities. In addition, the "inevitable impurities" mentioned here generally refer to those that exist in the raw materials of copper-based products or those that are unavoidably mixed in during the manufacturing process, and are originally unnecessary, but in trace amounts. It is an acceptable impurity because it does not affect the properties of copper-based products. Examples of components that can be cited as unavoidable impurities include nonmetallic elements such as sulfur (S) and metallic elements such as antimony (Sb). Note that the upper limit of the content of these components can be 0.05% by mass for each of the above components and 0.10% by mass for the total amount of the above components.

[2] Shape and metallographic structure of copper alloy material The shape of the copper alloy material of the present invention is not particularly limited, but may be formed by the hot or cold drawing process described below, press punching, etc. From the viewpoint of facilitating cutting, a plate material is preferable. Here, in a copper alloy material formed by rolling, such as a plate material, the rolling direction can be the stretching direction. On the other hand, the copper alloy material of the present invention may be in the form of a strip material such as a ribbon material, or a wire material such as a rectangular wire material or a round wire material, in addition to a plate material or a bar material. By forming the shape, cutting of the terminal can be easily performed. In particular, in copper alloy materials having these shapes 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 drawing direction.

Here, the copper alloy material contains oxides and carbides that are observed within a viewing area of 10,000 μm ² when viewed in a cross section perpendicular to the drawing direction (drawing direction, drawing direction, extrusion direction) during processing. Among the precipitated particles containing at least one of them, it is preferable that the number of coarse precipitated particles, which are precipitated particles having a maximum dimension of more than 20 μm, is 3 or less. As a result, manganese oxides and carbides are more uniformly dispersed in the copper alloy material, and the proportion of the sheared surface in the cross section when press punching the copper alloy material can be further increased. It is possible to improve punching workability and further improve the dimensional accuracy of the copper alloy material after press punching. In particular, precipitated particles with a maximum dimension of more than 20 μm tend to form a region around the particle where oxides and carbides are sparse, making the cross section uneven when press punched. It is preferable that the number contained in the alloy material is small. Therefore, from the viewpoint of making the cross section uniform during press punching and improving the processing accuracy in press punching, the number of coarse precipitated particles observed within a viewing area of 10,000 μm ² should be 3 or less. Preferably, the number is 1 or less, more preferably 0, and most preferably 0.

In this specification, the number of coarse precipitated particles containing oxides or carbides is measured by preparing a test material by embedding it in a resin so that the cross section perpendicular to the stretching direction during processing of the copper alloy material is exposed. After that, the cross section perpendicular to the stretching direction is polished, and the exposed crystals are observed using an optical microscope in a field of 100 μm x 100 μm to identify oxides and other substances that appear black in the microscopic image. This can be done by measuring the particle size of precipitated particles containing carbides.

[3] An example of a method for manufacturing a copper alloy material The above-described copper alloy material can be realized by controlling a combination of alloy composition and manufacturing process, and the manufacturing process is not particularly limited. Among them, the following method can be mentioned as an example of a manufacturing process that can obtain the above-mentioned copper alloy material.

As an example of the method for producing a copper alloy material of the present invention, a copper material having substantially the same alloy composition as the above-mentioned copper alloy material is subjected to at least a casting process [process 1], a homogenization heat treatment process [process 2], a hot working step [step 3], a first cold working step [step 4], and a first annealing step [step 5] are sequentially performed.

(i) Casting process [Process 1]
The casting process [Step 1] uses a high-frequency melting furnace to melt a copper-based material having the above-mentioned alloy composition in a non-oxidizing inert gas atmosphere or in a vacuum, and then casts it. An ingot having a predetermined shape (for example, 30 mm in thickness, 50 mm in width, and 300 mm in length) is produced. In addition, the alloy composition of the copper-based material may not necessarily completely match the alloy composition of the copper alloy material manufactured, as some additive components may adhere to or volatilize in the melting furnace during each manufacturing process. However, it has substantially the same alloy composition as that of the copper alloy material.

Here, the casting process [Step 1] is a copper-based material containing at least one of copper, manganese, nickel, graphite, and copper oxide, or copper, manganese, nickel, graphite, copper oxide, and any of the above-mentioned optional additive components. , melt and cast. Here, manganese has the characteristic of easily forming oxides and carbides, so by reacting with the carbon that makes up graphite and the oxygen contained in copper oxide, oxides and carbides with few coarse precipitated particles can be formed. It is possible to obtain precipitated particles containing. Therefore, since the copper alloy material obtained through the above manufacturing method can contain oxides and carbides within the range of the alloy composition mentioned above, it is possible to increase the strength of the obtained copper alloy material and improve press punching workability. can be improved.

In this casting process [Step 1], the molten metal of the copper-based material is held at a melting temperature in the range of 1100°C or more and 1250°C or less for a holding time of 2 hours or less, and then the average cooling rate is 0.5°C or more per second. It is preferable to obtain an ingot by cooling to 600°C or less. Thereby, fine oxides and carbides can be dispersed in the ingot with high uniformity. On the other hand, if the melting temperature is increased, the holding time at the melting temperature is increased, or the cooling rate during casting is slow, coarse oxides or carbides may increase. Therefore, from the viewpoint of improving press punching workability by reducing the precipitation of coarse oxides and carbides and dispersing oxides and carbides with high uniformity, the melting temperature in the casting process [Step 1] and the melting temperature The holding time and the cooling rate during casting are preferably within the above ranges. In particular, the holding time at the melting temperature is preferably 1 hour or less.

(ii) Homogenization heat treatment step [Step 2]
The homogenization heat treatment step [Step 2] is a step in which the ingot after the casting step [Step 1] is subjected to heat treatment for homogenization. Here, the conditions for the heat treatment in the homogenization heat treatment step [Step 2] are that the heating temperature is in the range of 750°C or more and 900°C or less, and the holding time at the heating temperature is 10 It is preferable to set the time to a range of not less than minutes and not more than 10 hours.

(iii) Hot processing process [Process 3]
In the hot working process [Step 3], the homogenized ingot is subjected to stretching processes such as hot rolling and wire drawing until it reaches a predetermined thickness and dimensions, and the hot-processed material is This is the manufacturing process. Here, the hot working step [Step 3] includes both a hot rolling step and a hot stretching (wire drawing) step. The conditions for the hot processing step [Step 3] are such that the processing temperature is preferably in the range of 750° C. or higher and 900° C. or lower, and may be the same as the heating temperature in the homogenization heat treatment step [Step 2]. Further, the processing rate in the hot working step [Step 3] is preferably 10% or more.

Here, "processing rate" is the value obtained by subtracting the cross-sectional area after processing from the cross-sectional area before stretching processing such as rolling or wire drawing, divided by the cross-sectional area before processing, multiplied by 100, and the percentage It is a value expressed by the following formula.
[Machining rate] = {([Cross-sectional area before machining] - [Cross-sectional area after machining])/[Cross-sectional area before machining]} x 100 (%)

The hot-processed material after the hot-processing step [Step 3] is preferably cooled. Here, the means for cooling the hot-processed material is not particularly limited, but from the viewpoint of making it difficult for crystal grains to coarsen, it is preferable to use a means that increases the cooling rate as much as possible, such as water cooling. It is preferable to set the cooling rate to 10° C./sec or more by the above means.

Here, the hot-processed material after cooling may be subjected to chamfering to scrape the surface. By performing surface cutting, the oxide film and defects on the surface generated in the hot working step [Step 3] can be removed. The conditions for surface cutting are not particularly limited as long as they are commonly used conditions. The amount removed from the surface of the hot-worked material by facing can be adjusted as appropriate based on the conditions of the hot-working step [Step 3], and is set to about 0.5 to 4 mm from the surface of the hot-worked material, for example. be able to.

(v) First cold working step [Step 4]
In the first cold working step [Step 4], the hot-worked material after the hot working step [Step 3] is cold rolled at an arbitrary processing rate according to the thickness and size of the product. This is the process of applying stretching processing such as wire drawing. Here, the first cold working step [Step 4] includes both a cold rolling step and a cold stretching (wire drawing) step. Conditions for stretching such as rolling and wire drawing in the first cold working step [Step 4] can be set according to the size of the hot worked material. In particular, from the viewpoint of promoting uniform precipitation of crystal grains through recrystallization in the first annealing step [Step 5], which will be described later, the total processing rate in the first cold working step [Step 4] may be set to 50% or more. preferable.

(vi) First annealing step [Step 5]
The first annealing step [Step 5] is an annealing step in which the cold-rolled material after the first cold working step [Step 4] is heat-treated and recrystallized. Here, the conditions for the heat treatment in the first annealing step [Step 5] are that the heating temperature is in the range of 600° C. or more and 800° C. or less, and the holding time at the heating temperature is in the range of 1 minute or more and 2 hours or less. On the other hand, if the heating temperature is less than 600° C. or the holding time is less than 1 minute, recrystallization of the copper alloy material becomes difficult. Moreover, when the heating temperature exceeds 800° C. or when the holding time exceeds 2 hours, the crystal grains may become coarse, resulting in a decrease in workability.

Here, it is preferable to repeatedly perform the cold working step and the annealing step one or more times on the cold rolled material after performing the first annealing step [step 5]. For example, the cold rolled material after performing the first annealing step [Step 5] may be subjected to a second cold working step and an annealing step, and the cold working step and annealing step at this time are They can be respectively a second cold working step [step 6] and a second annealing step [step 7]. In this way, by repeating the cold working process and annealing process one or more times, the copper alloy material becomes a plate, bar, strip, or wire with a desired shape, and coarse crystal grains are difficult to form. Therefore, it is possible to obtain a copper alloy material exhibiting desired properties in terms of workability, volume resistivity, and thermoelectromotive force against copper.

At this time, the total processing rate in the second cold working step [Step 6] can be 50% or more. Further, the conditions for the heat treatment in the second annealing step [Step 7] are that the heating temperature is in the range of 600° C. or more and 800° C. or less, and the holding time at the heating temperature is in the range of 1 minute or more and 2 hours or less.

[4] Applications of copper alloy material The copper alloy material of the present invention is extremely useful as a resistance material for a resistor, such as a shunt resistor or a chip resistor. That is, the resistance material for the resistor is preferably made of the above-mentioned copper alloy material. Moreover, it is preferable that a resistor such as a shunt resistor or a chip resistor has a resistor material made of the above-mentioned copper alloy material.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims. It can be modified to .

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

(Invention Examples 1 to 17 and Comparative Examples 1 to 6)
As a copper-based material, copper, manganese, nickel, graphite, copper oxide, and optional additives are mixed according to the alloy composition ratio shown in Table 1, melted in a non-oxidizing atmosphere in a high-frequency melting furnace, and then melted from the molten metal. A casting step [Step 1] of cooling and casting to 600° C. was performed to obtain an ingot. Here, among the components listed in Table 1, optionally added components marked with a horizontal line "-" are not added to the copper-based material as raw materials. Further, the temperature at which the copper-based material is melted (melting temperature), the holding time at the melting temperature, and the cooling rate of the molten metal after the holding time has elapsed are as listed in Table 1.

This ingot was subjected to a homogenization heat treatment step [Step 2] in which heat treatment was performed at a heating temperature of 800°C and a holding time of 5 hours, and then at a processing temperature of 800°C, the total processing rate was 67% (processing A hot-worked material was obtained by performing a hot-working step [Step 3] of rolling along the longitudinal direction so that the thickness before processing was 30 mm and the thickness after processing was 10 mm. Thereafter, it was cooled to room temperature by water cooling, and surface cutting was performed to remove the oxide film formed on the surface. The thickness of the hot-worked material after face cutting was 8 mm.

The hot-worked material after the hot working step [Step 3] is rolled along the longitudinal direction at a total working rate of 88% (thickness before working is 8 mm, thickness after working is 1 mm). A cold working step [Step 4] was performed. Next, the cold rolled material after performing the first cold working step [Step 4] is heat treated at a heating temperature of 600° C. or higher and 800° C. or lower for a holding time of 1 minute or more and 2 hours or less. The first annealing step [Step 5] was performed.

Furthermore, after performing the first annealing step [Step 5], the hot-worked material was processed in the longitudinal direction at a total processing rate of 70% (thickness before processing was 1 mm, thickness after processing was 0.3 mm). A second cold working step [Step 6] of rolling along the curve was performed. Next, the cold rolled material after performing the second cold working step [Step 6] is heat treated at a heating temperature of 600° C. or higher and 800° C. or lower for a holding time of 1 minute or more and 2 hours or less. A second annealing step [Step 7] was performed. In this way, copper alloy sheet materials of Inventive Examples 1 to 17 and Comparative Examples 1 to 6 were produced.

In addition, in Table 1, a horizontal line "-" is written in the column of the component that is not included in the alloy composition of the copper-based material, indicating that the component does not contain the corresponding component, or even if it does, it is below the detection limit value. revealed.

[Various measurement and evaluation methods]
The following characteristic evaluations were performed using the copper alloy materials (copper alloy plate materials) according to the above-mentioned examples of the present invention and comparative examples. The evaluation conditions for each characteristic are as follows.

[1] Measurement of the number of coarse precipitated particles containing oxides or carbides The produced copper alloy material was embedded in resin so that the cross section perpendicular to the stretching direction during processing of the copper alloy material was exposed. After producing the sample material, the cross section perpendicular to the stretching direction was polished. Next, the cross section of the polished sample material was observed using an optical microscope (manufactured by Olympus, model number: GX71) with a field of view of 100 μm x 100 μm square, and oxides and carbides that appeared in black in the microscopic image were observed. Among the precipitated particles containing at least one of the following, coarse precipitated particles having a maximum dimension of more than 20 μm were counted. In the inventive examples and comparative examples, after observing the cross section of the test material after polishing, the cross section perpendicular to the drawing direction of the test material was further polished, and the cross section of the test material at different positions in the drawing direction was observed. By repeating exposing and similarly counting the coarse precipitated particles in the cross section, the average value of the number of coarse precipitated particles in 5 fields of view was determined, and the obtained average value was taken as the number of coarse precipitated particles present. The results are shown in Table 2.

[2] Evaluation method of press punching workability The press punching workability of the produced copper alloy material was evaluated according to the shear test method for copper and copper alloy thin plate strips specified in the Japan Copper Brass Association technical standard JCBA T310:2019. A shear test was conducted. That is, for the copper alloy material, the clearance between the upper die (punch) and the lower die (die) was adjusted to be 10 μm, the size along the stretching direction y was 2 mm, and the width was perpendicular to the stretching direction y. A test material of a copper alloy material 1 having a cut surface 2 on the outer periphery was produced by punching a rectangular shape having a size of 10 mm along the direction intersecting the (x direction in FIG. 1).

FIG. 1 is a schematic diagram showing a cut surface when press punching is performed on the copper alloy material of the present invention. The copper alloy material 1 shown in FIG. 1 shows a cut surface 2 after being subjected to press punching, which is performed by lowering an upper die (punch) while being fixed on a lower die (not shown). be. Here, on the cut surface 2, a sag 3, a shear surface 4, and a fracture surface 5 are formed in order from the upper surface 1a side of the press-punched copper alloy material 1. Further, a burr 6 is often formed on the lower edge of the cut surface 2 so as to extend outward from the fracture surface 5. Therefore, the cross section of the copper alloy material 1 including the thickness direction and the width direction includes the sagging 3, the sheared surface 4, the fractured surface 5, and the burr 6.

In this example, a scanning electron microscope (SEM) was used to examine a cross section of the formed cut surface 2 that includes the thickness direction z and the width direction x, which is a surface along a direction perpendicular to the stretching direction y. ) (manufactured by Shimadzu Corporation, SSX-550) at a magnification of 200 times. Then, from a scanning electron microscope (SEM) photograph of the cut surface 2, the ratio of the cross-sectional area of the sheared surface 4 to the cross-sectional area of the cross section including the thickness direction and the width direction was calculated.

If the ratio of the cross-sectional area of the shear plane 4 to the calculated cross-sectional area of the cross-section including the thickness direction and the width direction is 40% or more, the press punching workability is evaluated as "◎" as being excellent. did. In addition, when the ratio of the cross-sectional area of the shear plane 4 to the cross-sectional area of the cross-section including the thickness direction and the width direction is 35% or more and less than 40%, the press punching workability is evaluated as "○". evaluated. On the other hand, when this ratio was less than 35%, the press punching workability was considered to be poor and it was evaluated as "x". The results are shown in Table 2.

[3] Measurement of volume resistivity Regarding the produced copper alloy material, the obtained plate material with a thickness of 0.3 mm was cut into a width of 10 mm and a length of 300 mm to produce a test material.

The volume resistivity ρ is measured by measuring the voltage using the four-probe method according to the method specified in JIS C2525 at a room temperature of 20°C with a distance between the voltage terminals of 200 mm and a measurement current of 100 mA, and from the obtained value. The volume resistivity ρ [μΩ·cm] was determined.

When the measured volume resistivity ρ was 80 μΩ·cm or more, the volume resistivity ρ was sufficiently large and the material was evaluated as “◎” as being excellent as a resistive material. Further, when the volume resistivity ρ was 70 μΩ·cm or more and less than 80 μΩ·cm, the volume resistivity ρ was large and the material was evaluated as “good” as a good resistive material. On the other hand, when the volume resistivity ρ was less than 70 μΩ·cm, the volume resistivity ρ was small and the material was evaluated as “x” as being poor as a resistive material. In this example, "◎" and "○" were evaluated as passing levels. The results are shown in Table 2.

[4] Method for measuring thermoelectromotive force (EMF) against copper The produced copper alloy material was cut into a 0.3 mm thick plate material with a width of 10 mm and a length of 1000 mm to produce a test material.

The copper thermoelectromotive force (EMF) of the sample material was measured in accordance with JIS C2527. More specifically, as shown in FIG. 2, the apparatus 10 for measuring the copper thermoelectromotive force (EMF) of the test material 11 uses a standard copper wire 21 using a sufficiently annealed pure copper wire with a diameter of 1 mm or less. The temperature measuring contact _P1 to which the test material 11 and one end of the standard copper wire 21 are connected is immersed in hot water maintained in a constant temperature bath 41 at 80°C. The electromotive force when the reference junctions P ₂₁ and P ₂₂ , in which the other ends of the standard copper wire 21 are connected to the copper wires 31 and 32, respectively, are immersed in 0°C ice water kept cool by the freezing point device 42 is calculated as follows: , was measured with a voltage measuring device 43. The thermoelectromotive force EMF (μV/°C) against copper was determined by dividing the obtained electromotive force by the temperature difference of 80 [°C].

When the absolute value of the measured thermal electromotive force (EMF) against copper is 0.6 μV/℃ or less, it is considered that the absolute value of the thermal electromotive force (EMF) against copper is small and is good as a resistive material. It was rated as “〇”. On the other hand, if the absolute value of thermoelectromotive force (EMF) against copper is larger than 0.6 μV/°C, it is marked as "×" because the absolute value of thermoelectromotive force (EMF) against copper is large and is defective as a resistive material. evaluated. The results are shown in Table 2.

[5] Comprehensive evaluation Of the three evaluation results regarding press punching workability, volume resistivity ρ, and copper thermoelectromotive force (EMF), both of the evaluation results for press punching workability and volume resistivity ρ were rated “◎”. If the thermoelectromotive force (EMF) against copper is evaluated as "○", the three properties of press punching workability, volume resistivity ρ, and thermoelectromotive force (EMF) against copper are considered to be excellent. It was rated as ◎. Also, among these three evaluation results, one or both of the evaluation results of press punching workability and volume resistivity ρ, and thermoelectromotive force (EMF) against copper were evaluated as "○", and the rest were evaluated as "◎". In the case where the evaluation was made as follows, it was evaluated as "○", indicating that these three characteristics were at least good. On the other hand, if the evaluation result is "x" in at least one of press punching workability, volume resistivity ρ, and thermoelectromotive force (EMF) against copper, it is considered that at least one of these three properties is It was evaluated as "x" as a failure. The results are shown in Table 2.

From the results in Tables 1 and 2, the copper alloy materials of Examples 1 to 17 of the present invention have alloy compositions within the appropriate range of the present invention, and when viewed in a cross section perpendicular to the stretching direction, oxide The number of coarse precipitated particles containing at least one of carbide and carbide was 3 or less in each case, so it was evaluated as "◎" or "〇" in the evaluation of volume resistivity ρ and press punching workability. there were. Further, the copper alloy materials of Examples 1 to 17 of the present invention were all evaluated as "Good" in terms of thermoelectromotive force (EMF) against copper.

On the other hand, the copper alloy material of Comparative Example 1 had a small total amount of O and C, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 1 was evaluated as "poor" in terms of press punching workability.

Further, the copper alloy material of Comparative Example 2 had a large total amount of O and C, which was outside the appropriate range of the present invention. Therefore, in the copper alloy material of Comparative Example 2, cracks occurred during rolling in the hot working step [Step 3].

Further, the copper alloy material of Comparative Example 3 had a low Mn content, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 3 was evaluated as "x" in terms of volume resistivity ρ.

Further, the copper alloy material of Comparative Example 4 had a high Mn content, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 4 was evaluated as "x" in terms of thermoelectromotive force (EMF) against copper.

Further, the copper alloy material of Comparative Example 5 had a high Ni content, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 5 was evaluated as "x" in terms of thermoelectromotive force (EMF) against copper.

Further, the copper alloy material of Comparative Example 6 had a low Ni content, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 6 was evaluated as "x" in terms of thermoelectromotive force (EMF) against copper.

From this result, it was confirmed that the copper alloy material of the present invention example has at least good volume resistivity ρ and thermoelectromotive force (EMF) against copper when the alloy composition is within the appropriate range of the present invention. . At the same time, it was confirmed that the copper alloy material of the example of the present invention had at least good press punching workability.

Further, FIG. 3 shows an example of an optical micrograph of a cross section perpendicular to the stretching direction during processing of the copper alloy material of Inventive Example 9, when observed within a viewing area of 10,000 μm ² . In this optical micrograph, precipitated particles containing at least one of oxide and carbide appear as black dots. From the optical micrograph in Figure 3, it was confirmed that coarse precipitated particles containing at least one of oxides and carbides, which are precipitated particles with a maximum dimension of more than 20 μm, were not precipitated within the field of view. .

In addition, FIGS. 4 and 5 show cross-sections including the thickness direction and width direction of the copper alloy materials of the present invention example and comparative example when press punching was performed using a scanning electron microscope. (SEM) A photograph is shown. Here, FIG. 4 is an SEM photograph of a cut surface when press punching was performed on the copper alloy material of Inventive Example 11, and FIG. 5 is an SEM photograph of the cut surface when press punching was performed on the copper alloy material of Comparative Example 1. This is an SEM photograph of the cut surface when the specimen was cut. In addition, in FIG. 4 and FIG. 5, the boundary between the shear plane 4, 400 and the fracture plane 5, 500 is shown by a broken line. From these SEM photographs, it can be seen that in the copper alloy material 1 of the example of the present invention, the ratio of the cross-sectional area of the shear plane 4 to the cross-sectional area of the cross section including the thickness direction and the width direction is the same as that of the copper alloy material 100 of the comparative example. It was confirmed that the ratio of the cross-sectional area of

1 Copper alloy material 1a Top surface of copper alloy material 1b Bottom surface of copper alloy material 2,200 Cut surface 3,300 Sagging 4,400 Shear surface 5,500 Fracture surface 6,600 Burr 7 Boundary line 10 Copper thermoelectromotive force (EMF) ) Measuring device 11 Test material 21 Standard copper wire 31, 32 Copper wire 41 Constant temperature chamber 42 Freezing point device 43 Voltage measuring device 100 Copper alloy material of comparative example 100a Top surface of copper alloy material of comparative example 100b Copper alloy material of comparative example Bottom surface P ₁ temperature measuring junction P ₂₁ , P ₂₂ reference junction x Width direction y Stretching direction z Thickness direction

Claims (5)

Contains Mn: 20.0% by mass or more and 35.0% by mass or less and Ni: 6.5% by mass or more and 17.0% by mass or less,
An alloy containing O: 0 mass ppm or more and 800 mass ppm or less and C: 0 mass ppm or more and 800 mass ppm or less, and containing a total of 60 mass ppm or more and 800 mass ppm or less of O and C, with the balance consisting of Cu and inevitable impurities. Copper alloy material with the composition. Among the precipitated particles containing at least one of an oxide and a carbide, which are observed within a viewing area of 10,000 μm ² when viewed in a cross section perpendicular to the stretching direction during processing of the copper alloy material, the maximum dimension is 20 μm. The copper alloy material according to claim 1, wherein the number of coarse precipitated particles, which are super precipitated particles, is 3 or less. The alloy composition is
Fe: 0.01% by mass or more and 0.50% by mass or less,
Co: 0.01% by mass or more and 2.00% by mass or less,
Sn: 0.01% by mass or more and 5.00% by mass or less,
Zn: 0.01% by mass or more and 5.00% by mass or less,
Cr: 0.01% by mass or more and 0.50% by mass or less,
Ag: 0.01% by mass or more and 0.50% by mass or less,
Al: 0.01% by mass or more and 1.00% by mass or less,
Mg: 0.01% by mass or more and 0.50% by mass or less,
Claim 1 further comprising at least one component selected from the group consisting of Si: 0.01% by mass or more and 0.50% by mass or less, and P: 0.01% by mass or more and 0.50% by mass or less. Copper alloy material described in . A resistance material for a resistor, comprising the copper alloy material according to any one of claims 1 to 3. A resistor comprising the resistor material according to claim 4.

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