TW202043492A - Copper alloy strip and method for manufacturing same, resistor resistance material using same, and resistor - Google Patents

Abstract

A copper alloy strip according to the present invention has an alloy composition containing 3-20 mass% of manganese with the remainder comprising copper and inevitable impurities, wherein the average value of KAM is at least 1 DEG and less than 5 DEG as measured by an electron backscatter diffraction method. The copper alloy strip is suitable for manufacturing chips, etc. by press processing, and has a small variation in resistance values between products or lots.

Description

Copper alloy strip and its manufacturing method, resistance material for resistor using the copper alloy strip and resistor

The present invention relates to a copper alloy strip and a manufacturing method thereof, a resistance material for resistors and resistors using the copper alloy strip, and particularly relates to a copper alloy strip suitable for punching processing to produce chips Etc., and the variation of the resistance value of the manufactured small pieces is small.

For the metal material of the resistance material used in the resistor, it is required that its index, that is, the temperature coefficient of resistance (TCR), be so small that the resistance of the resistor is stable even if the ambient temperature changes. The temperature coefficient of resistance is the change in resistance value caused by temperature, expressed in parts per million (ppm) per 1℃, and is expressed by TCR (×10 ^-6 /K) = {(RR ₀ )/R ₀ }×{1/(TT ₀ )}×10 ⁶ expression. Here, T in the formula represents the test temperature (unit: ℃), T ₀ represents the reference temperature (unit: ℃), R represents the resistance value at the test temperature T (unit: Ω), R ₀ represents the reference temperature T ₀ The resistance value (unit: Ω). Copper-manganese-nickel (Cu-Mn-Ni) alloy and copper-manganese-tin (Cu-Mn-Sn) alloy have very small TCR, so they are widely used as alloy materials that constitute resistance materials.

In addition, in the resistance material manufactured by stamping this alloy material, strain is introduced into the alloy material during the stamping forming, and thus the resistance value will vary, and the resistance material cannot be produced stably.

Patent Document 1 discloses that the copper alloy material is heated in a non-oxidizing atmosphere based on hydrogen after performing a rolling treatment with a high rolling reduction rate, thereby removing residual strain, and as a result, reducing the resistance temperature coefficient. However, even with such an alloy material manufactured in this way, the strain will remain unevenly, so there may be a deviation in the resistance value. [Prior Technical Literature] (Patent Document)

Patent Document 1: Japanese Patent Laid-Open No. 2016-69724

[The problem to be solved by the invention]

The present invention is completed in view of the above actual situation, and aims to provide a copper alloy strip and a method for manufacturing the copper alloy strip. The copper alloy strip is suitable for stamping to produce small pieces, and between products and batches ( lot) The deviation of the resistance value is small. [Technical means to solve the problem]

The inventors have repeated the results of in-depth investigations and found that the alloy composition of the copper alloy strip contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The average value of the Kernal Average Misorientation (KAM) measured by the electron backscatter diffraction (EBSD) method is 1° or more and less than 5°, then the implementation of this kind of copper alloy strip In the small pieces manufactured by stamping, the difference in resistance value between products and between batches is small; moreover, this copper alloy strip can be manufactured by a manufacturing method including the following steps: the first heat treatment step, For copper alloy materials with an alloy composition that is substantially the same as the alloy composition of the aforementioned copper alloy strips, heating is performed in a high temperature region above 800°C and below 950°C; hot working step; will be implemented with a high processing rate of more than 50% The first cold working step of cold working, and the second heat treatment step of heating in the middle temperature region of 400°C or higher and 700°C or lower are more than one set of steps; the second cold working step (second cold rolling step) , Perform cold working with a low processing rate of 5% or more and less than 50%; and, the third heat treatment step, after the temperature rise rate of 200°C/min (°C/min) or more reaches 200°C or more and less than 400°C, Hold for 10 to 55 seconds, and then cool to less than 50°C at a cooling rate of 100°C/min or higher. The present invention has been completed based on the above findings.

That is, the main structure of the present invention is as follows. (1) A copper alloy strip, the alloy composition of which contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The copper alloy strip is characterized by: The average value of KAM measured by scattered electron diffraction method is 1° or more and less than 5°. (2) The copper alloy strip as described in (1) above, wherein the value of KAM is 1° or more and less than 4° in relation to the total area of KAM measured by the backscattered electron diffraction method The ratio is more than 50%. (3) The copper alloy strip as described in (1) or (2) above, wherein the value of KAM is 6° or more and less than the total area of KAM measured by the backscattered electron diffraction method The ratio of the area of 15° is 3% or more and 25% or less. (4) The copper alloy strip according to any one of (1) to (3) above, wherein the Vickers hardness (Vickers hardness) is 150 or more and 200 or less. (5) The copper alloy strip according to any one of (1) to (4) above, wherein the alloy composition further contains one or more elements selected from the group consisting of: 0.01 mass % Or more and 5 mass% or less of nickel; 0.01 mass% or more and 5 mass% or less tin; 0.01 mass% or more and 5 mass% or less zinc; 0.01 mass% or more and 0.5 mass% or less iron; 0.01 mass% or more And 0.5 mass% or less silicon; 0.01 mass% or more and 0.5 mass% or less chromium; 0.01 mass% or more and 0.5 mass% or less zirconium; 0.01 mass% or more and 0.5 mass% or less titanium; 0.01 mass% or more and 0.5 mass% Mass% or less silver; 0.01 mass% or more and 0.5 mass% or less magnesium; 0.01 mass% or more and 0.5 mass% or less cobalt; and 0.01 mass% or more and 0.5 mass% or less phosphorus. (6) A method of manufacturing a copper alloy strip, which is a method of manufacturing the copper alloy strip according to any one of (1) to (5) above, the method of manufacturing is characterized by comprising the following steps: A heat treatment step, for a copper alloy material having an alloy composition substantially the same as the alloy composition of the aforementioned copper alloy strip, heating is performed in a high temperature region above 800°C and below 950°C; the hot working step; The first cold working step of cold working with high processing rate, and the second heat treatment step of heating in the middle temperature range of 400°C or more and 700°C as a group of steps or more; the second cold working step is 5 Cold working is performed at a low working rate of 50% or more and less than 50%; and, in the third heat treatment step, after reaching 200°C or more and less than 400°C at a temperature increase rate of 200°C/min or more, hold for 10 to 55 seconds, and then, Cool at a cooling rate of 100°C/min or more to less than 50°C. (7) A resistance material for resistors, which uses the copper alloy strip according to any one of (1) to (5) above. (8) A resistor having the resistive material described in (7) above. [Effect of Invention]

According to the present invention, it is possible to provide a copper alloy strip and a method for manufacturing the copper alloy strip. The copper alloy strip is suitable for stamping to produce small pieces, and the resistance value deviation between products and between batches is small .

(1) Copper alloy strip Hereinafter, the preferred embodiments of the copper alloy strip of the present invention will be described in detail. According to the copper alloy strip of the present invention, the alloy composition contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The characteristic of the copper alloy strip is: The average value of KAM measured by scattered electron diffraction method is 1° or more and less than 5°.

In this copper alloy strip, by containing 3% by mass or more of manganese (Mn), appropriate strain is generated in the copper alloy strip, and an appropriate KAM value can be obtained. On the other hand, in the copper alloy strip, the average value of KAM measured by the backscattered electron diffraction method is 1° or more and less than 5°, and the copper alloy strip will have a very small amount of strain. With this strain, the strain caused by press processing can be suppressed (offset), and the deviation of the resistance value between products and batches can be suppressed.

＜Composition of copper alloy strips＞ [Manganese: 3% by mass or more and 20% by mass or less] The copper alloy strip of the present invention contains 3% by mass or more and 20% by mass or less of manganese. Manganese (Mn) is an essential component in the present invention. With the content of manganese within this range, the temperature coefficient of resistance of the copper alloy material can be reduced. In contrast, if the manganese content is less than 3% by mass, the effect of reducing the temperature coefficient of resistance cannot be sufficiently obtained. In addition, when the content of manganese is more than 20% by mass, the amount of strain during processing increases, so when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. From the viewpoint of the temperature coefficient of resistance, the content of manganese is preferably 5% by mass or more.

＜Arbitrary composition of copper alloy strips＞ In addition, the alloy strip of the present invention can further contain one or more elements selected from the group consisting of: 0.01 mass% or more and 5 mass% or less of nickel; 0.01 mass% or more as optional additional components And 5 mass% or less tin; 0.01 mass% or more and 5 mass% or less zinc; 0.01 mass% or more and 0.5 mass% or less iron; 0.01 mass% or more and 0.5 mass% or less silicon; 0.01 mass% or more and 0.5 mass% Mass% or less chromium; 0.01 mass% or more and 0.5 mass% or less zirconium; 0.01 mass% or more and 0.5 mass% or less titanium; 0.01 mass% or more and 0.5 mass% or less silver; 0.01 mass% or more and 0.5 mass% The following magnesium; 0.01 mass% to 0.5 mass% of cobalt; and 0.01 mass% to 0.5 mass% of phosphorus. Any of these elements are added for the purpose of improving the temperature coefficient of resistance, adjusting the volume resistivity, etc. However, if the addition exceeds the respective specified range, the characteristics such as the resistance value may change even if the operating temperature is less than 400°C. , The cost of raw materials will increase. Hereinafter, each metal element will be described separately.

[Nickel: 0.01 mass% or more and 5 mass% or less] The content of nickel (Ni) is not particularly limited, but is preferably 0.01% by mass or more and 5% by mass or less. If the nickel content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of nickel exceeds 5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it will become difficult to obtain an appropriate strain distribution. In addition, the content of nickel may be, for example, 0% by mass or more (including the case where nickel is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Tin: 0.01 mass% or more and 5 mass% or less] The content of tin (Sn) is not particularly limited, but is preferably 0.01% by mass or more and 5% by mass or less. If the tin content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of tin exceeds 5% by mass, the amount of strain during processing will increase, so when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of tin may be, for example, 0% by mass or more (including the case where tin is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Iron: 0.01% by mass or more and 0.5% by mass or less] The content of iron (Fe) is not particularly limited, but is preferably 0.01% by mass or more and 0.5% by mass or less. If the iron content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of iron exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it will become difficult to obtain an appropriate strain distribution. In addition, the iron content may be, for example, 0% by mass or more (including the case where iron is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Zinc: 0.01 mass% or more and 5 mass% or less] The content of zinc (Zn) is not particularly limited, but is preferably 0.01% by mass or more and 5% by mass or less. If the zinc content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of zinc exceeds 5% by mass, there is a possibility that the resistance value will vary due to a dezincification phenomenon. In addition, the content of zinc may be, for example, 0% by mass or more (including the case where zinc is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Silicon: 0.01% by mass or more and 0.5% by mass or less] The content of silicon (Si) is not particularly limited, but is preferably 0.01% by mass or more and 0.5% by mass or less. If the content of silicon is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of silicon exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of silicon may be, for example, 0 mass% or more (including the case where silicon is not included), 0.001 mass% or more, or 0.005 mass% or more.

[Chromium: 0.01% by mass or more and 0.5% by mass or less] The content of chromium (Cr) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the chromium content is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of chromium exceeds 0.5% by mass, the amount of strain during processing increases, and when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of chromium may be, for example, 0% by mass or more (including the case where chromium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Zirconium: 0.01% by mass or more and 0.5% by mass or less] The content of zirconium (Zr) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of zirconium is less than 0.01% by mass, the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of zirconium exceeds 0.5% by mass, the amount of strain during processing will increase, so when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of zirconium may be, for example, 0% by mass or more (including the case where zirconium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Titanium: 0.01% by mass or more and 0.5% by mass or less] The content of titanium (Ti) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the titanium content is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of titanium exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it will become difficult to obtain an appropriate strain distribution. In addition, the content of titanium may be, for example, 0% by mass or more (including the case where titanium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Silver: 0.01% by mass or more and 0.5% by mass or less] The content of silver (Ag) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the silver content is less than 0.01%, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of silver exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of silver can be, for example, 0% by mass or more (including the case where silver is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Magnesium: 0.01% by mass or more and 0.5% by mass or less] The content of magnesium (Mg) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of magnesium is less than 0.01% by mass, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of magnesium exceeds 0.5% by mass, the amount of strain during processing increases, and when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of magnesium may be, for example, 0% by mass or more (including the case where magnesium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Cobalt: 0.01% by mass or more and 0.5% by mass or less] The content of cobalt (Co) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of cobalt is less than 0.01% by mass, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of cobalt exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it becomes difficult to obtain an appropriate strain distribution. In addition, the content of cobalt may be, for example, 0% by mass or more (including the case where cobalt is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Phosphorus: 0.01% by mass or more and 0.5% by mass or less] The content of phosphorus (P) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the phosphorus content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the phosphorus content exceeds 0.5% by mass, the amount of strain during processing will increase, and when heat treatment is performed in a low temperature region, it will become difficult to obtain an appropriate strain distribution. In addition, the content of phosphorus may be, for example, 0% by mass or more (including the case where phosphorus is not included), 0.001% by mass or more, or 0.005% by mass or more.

[The rest: copper and inevitable impurities] In addition to the aforementioned essential components and optional additional components, the remainder is composed of copper (Cu) and inevitable impurities. In addition, the term "unavoidable impurities" here means that most of the copper-based products are present in the raw materials or inevitably mixed in the manufacturing process. They are originally unnecessary components, but they are very small and do not affect The characteristics of the copper-based products affect, so the impurities can be tolerated. Examples of components that can be cited as unavoidable impurities include non-metal elements such as sulfur (S) and oxygen (O), and metal elements such as aluminum (Al) and antimony (Sb). In addition, the upper limit of the content of these components may be 0.05% by mass for each of the above components, and 0.20% by mass based on the total amount of the components.

＜Crystal structure of copper alloy strip＞ The alloy bar of the present invention is characterized in that the average value of KAM measured by backscattered electron diffraction (EBSD) is 1° or more and less than 5°.

As described above, when the average value of KAM is 1° or more and less than 5°, the copper alloy strip will have a very small amount of strain, and this strain will suppress (offset) the occurrence of stamping Strain, and can suppress the deviation of the resistance value between products and between batches. On the other hand, if the average value of KAM is less than 1°, the copper alloy strip will be in a state with little strain (the state after recrystallization). The strain will be introduced by press processing, resulting in inter-products and batches There is a deviation in the resistance value between. In addition, if the average value of KAM is 5° or more, the resistance value will fluctuate due to the influence of heat generated during use or assembly, and the resistance value between products and batches may occur. The risk of deviation.

Compared with the total area of KAM measured by the backscattered electron diffraction method, the ratio of the area where the value of KAM is 1° or more and less than 4° is preferably 50% or more. By making: The ratio of the area where the value of KAM is 1° or more and less than 4° occupies 50% or more relative to the whole area of the measured KAM, which can effectively suppress the resistance between products and batches The deviation. When the value of KAM is 1° or more and the ratio of the area less than 4° is small, it means that there is more than 1° or more than 4°. When the value is less than 1°, the strain is less There are many states. When the temperature is more than 4°, there are many high strain areas. For example, it will be easily affected by heat during assembly, and there will be slight temperature fluctuations. In a short time, the resistance value will be greatly affected, so the deviation Will become bigger. The value of KAM is the ratio of the area of 1° or more and less than 4°, preferably 50% or more, and more preferably 50% or more and less than 70%.

In addition, it is preferable that the ratio of the area where the value of KAM is 6° or more and less than 15° is 3% or more and 25% or less relative to the total area of KAM measured by the backscattered electron diffraction method . The ratio of the area where the value of KAM is 6° or more and less than 15° to the total area where KAM is measured is 3% or more and 25% or less, which means that there is an area lacking ductility. It will become the starting point of breaking during stamping, so stamping can be done without increasing the amount of strain in the alloy, which can improve dimensional accuracy and more effectively suppress the deviation of resistance values between products and between batches. Furthermore, the value of KAM is the ratio of the area of 6° or more and less than 15°, and more preferably 5% or more and 25% or less.

In addition, KAM used JSM-7001FA manufactured by JEOL Ltd. and measured by the backscattered electron diffraction method. The cross section of the copper alloy strip parallel to the rolling direction is made into a measurement sample by resin filling, electrolytic polishing, etc., for mirror finish. And, for example, by immersing a copper alloy strip in a phosphoric acid solution and conducting electrolytic polishing for 60 seconds, the surface of the sample can be mirror-polished. In this cross-sectional sample, a field of view area of 100 μm×100 μm at the center of the plate thickness was used as the measurement target, and the measurement was performed with a step size of 0.05 μm. Using the analysis software OIM Analysis manufactured by TSL, all points are used as objects, and the first neighboring measurement value where the crystal orientation difference is 15° or more is used as the boundary to calculate the average value of KAM. In addition, in the field of view, the area of 0° or more and less than 15° is divided into 15 parts, and the area ratio per 1° is calculated to obtain the KAM measurement relative to the area measured The overall area is the ratio of the area of 1° or more and less than 4°, and the ratio of the area of 6° or more and less than 15°. Perform this measurement at any 5 locations and calculate the average value.

＜Physical properties of copper alloy bars＞ The Vickers hardness of the alloy strip of the present invention is not particularly limited, but is preferably 150 or more and 200 or less, and more preferably 150 or more and 190 or less. When the Vickers hardness is in this range, it is particularly possible to suppress strain due to press working, and in addition, it is possible to suppress the change in resistance value characteristics due to heat.

In addition, the Vickers hardness is measured from the surface of the copper alloy material in accordance with the method specified in JIS Z2244 (2009). The load (test force) at this time was 2.9 N, and the indenter time was 15 seconds (s).

The copper alloy strip of the present invention is extremely useful as a resistor, such as a resistor material for shunt resistors and chip resistors.

(2) Manufacturing method of copper alloy strip The method for manufacturing the copper alloy strip according to an embodiment of the present invention will be described in detail. This manufacturing method is characterized by including the following steps: a first heat treatment step, for a copper alloy material having an alloy composition substantially the same as the alloy composition of the aforementioned copper alloy strip, in a high temperature region above 800°C and below 950°C For heating; hot working step; when the first cold working step for cold working with a high processing rate of 50% or more, and the second heat treatment step for heating in a medium temperature region above 400°C and 700°C as a set of steps In the second cold working step (second cold rolling step), cold working is performed at a low working rate of 5% or more and less than 50%; and the third heat treatment step is performed at a temperature of 200°C/min or more After the speed reaches 200°C or higher and less than 400°C, hold for 10 to 55 seconds, and then cool to less than 50°C at a cooling rate of 100°C/min or higher. The following describes each step.

＜Production procedure of copper alloy material＞ The copper alloy material has an alloy composition substantially the same as the alloy composition of the aforementioned copper alloy strip. Examples of copper alloy materials include ingots manufactured by casting, but they are not particularly limited. Here, the alloy composition of the copper alloy material is set to be "substantially the same" as the alloy composition of the copper alloy strip. The reason is that it is assumed that in each step from the copper alloy material to the production of the copper alloy strip, when the copper alloy When the material contains easily volatilized (vaporized) components, etc., it will disappear due to vaporization (evaporation), and this is included.

<The first heat treatment step> The first heat treatment step is a step of heating the copper alloy material in a high temperature region above 800°C and below 950°C. By setting the heating temperature in the first heat treatment step to a high temperature range of 800°C or higher and 950°C or lower, solidification segregation, crystallized products and precipitates generated during casting can be eliminated, and the material can be homogenized .

The heating time in the first heat treatment step is not particularly limited, but it is preferably 10 minutes or more and 10 hours or less.

＜Heat processing steps＞ The hot working step is a step of processing (for example, rolling) at a temperature of about 800°C to 950°C so as to have a desired plate thickness. Regarding the hot working, there is no particular limitation if it is any of rolling processing or extrusion processing.

＜The first cold working step＞ The first cold working step is a step of performing cold working at a high working rate of 50% or more. In the first cold working step, cold working is appropriately performed according to a conventional method. By setting the processing rate in the first cold working step to a high processing rate of 50% or more, it is possible to ensure the amount of strain that becomes the driving force for recrystallization, and it is possible to facilitate recrystallization in the subsequent steps.

＜Second heat treatment step＞ The second heat treatment step is a step of heating in a medium temperature region of 400°C or higher and 700°C or lower. By setting the heating temperature in the second heat treatment step to an intermediate temperature range of 400° C. or more and 700° C. or less, it can be recrystallized to obtain a uniform structure with strain removed. In the second heat treatment step, heat treatment is appropriately performed according to a conventional method.

The heating time in the second heat treatment is not particularly limited, but it is preferably set to 10 seconds or more and 10 hours or less.

Moreover, when the above-mentioned first cold working step and second heat treatment step are regarded as a set of steps, only one set of steps may be performed, or two sets of steps or more may be repeated.

＜Second cold rolling step＞ The second cold rolling step is a step in which cold working is performed at a low working rate of 5% or more and less than 50%. By performing cold working at a low working rate in this way, it is possible to suppress uneven strain in the alloy material for rolling. On the other hand, if the working rate in the second cold rolling step is 50% or more, even if heating is performed in the third heat treatment step in the latter stage, the strain generated here is still non-uniform, so it is possible to suppress the production of press forming The deviation of the resistance value between products and batches. Furthermore, by setting it to 20% or more and less than 50%, it can be made that the ratio of the area where the value of KAM is 6° or more and less than 15° is within an appropriate range relative to the entire area where KAM is measured. .

<The third heat treatment step> The third heat treatment step, that is, the step of heating in the third heat treatment step, which is after reaching 200°C or more and less than 400°C at a temperature increase rate of 200°C/min or more, holding for 10 to 55 seconds, and then The step of cooling at a cooling rate of 100°C/min or higher to less than 50°C. By heating in the low temperature region in this way, the crystal grains will not recrystallize, and the strain in the crystal will be suppressed and adjusted, so the average value of KAM measured by the backscattered electron diffraction method will become 1. ° above and less than 5 °. Furthermore, by setting it to 250°C or higher, it is possible to create: the ratio of the area where the KAM value is 6° or more and less than 15° relative to the entire area where KAM is measured, and the area where KAM is measured Overall, the value of KAM is the ratio of the area of 1° or more and less than 4°, which is within an appropriate range.

In addition, the above method of manufacturing a copper alloy strip may be provided with steps other than the above steps. For example, it can be mentioned: the thick oxide film formed after the thermal processing step, the surface grinding step of removing by mechanical grinding, the degreasing step of removing the rolling oil, the thin film produced by the heat treatment The oxide film is used for mechanical or chemical removal in the polishing step, and the anti-rust step to prevent discoloration.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments, and includes the concept of the present invention and all aspects included in the scope of the patent application. Various changes can be made within the scope of the present invention. (Example)

Subsequently, in order to further clarify the effect 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 15, comparative examples 1 to 5) An ingot (weight: 10 kg) having the alloy composition described in the "alloy composition" column of Table 1 was produced by casting. For this ingot, the first heat treatment step is performed under the conditions of a heating temperature of 800°C or more and 950°C or less, and a heating time of 10 minutes or more and 10 hours or less to homogenize the alloy composition and set the processing rate to More than 70% of the heat processing steps are formed into a plate (size: length 500mm, width 100mm, thickness 10mm) and water-cooled to obtain a plate.

Subsequently, a first cold working step with a high processing rate of 90% or more is performed, and a second heat treatment step is performed for heating in a medium temperature region above 400°C and below 700°C. In addition, the first cold working step and the second heat treatment step were performed once (a set) in Examples 1 to 5, 7, 8, 10 to 15 of the present invention and Comparative Examples 1 to 5, respectively. In addition, in Examples 6 and 9 of the present invention, in the first group and the second group, the processing rate and heating conditions were changed, and the treatment was performed twice (two groups) respectively.

After that, proceed: the second cold working step, which is carried out at a low working rate of 5% or more and less than 50%; and the third heat treatment step, which reaches 200°C or more and less than 400°C at a temperature increase rate of 200°C/min or more After that, it is held for 10 to 55 seconds, and then cooled to less than 50°C at a cooling rate of 100°C/min or more. In addition, for Comparative Example 1, the second cold working step and the third heat treatment step were not performed, and for Comparative Example 4, the third heat treatment step was not performed. Therefore, in Table 1, the column of the step not performed is marked "-".

[Composition of copper alloy strip] The chemical composition of the copper alloy strip was determined by ICP (Inductively Coupled Plasma) analysis and is shown in Table 1 below.

[Backscattered electron diffraction method] KAM used JSM-7001FA manufactured by JEOL Ltd. and measured by the backscattered electron diffraction method. The cross section of the copper alloy strip parallel to the rolling direction is mirror-polished by resin filling, electrolytic polishing, etc., to prepare measurement samples. In this cross-sectional sample, a field of view area of 100 μm×100 μm at the center of the plate thickness was used as the measurement target, and the measurement was performed in a step size of 0.05 μm. Using the analysis software OIM Analysis manufactured by TSL Corporation, the average value of KAM was calculated using the case where the crystal orientation difference was 15° or more as the boundary. In addition, in this field of view, the range of 0° or more and less than 15° is divided into 15 parts (0° or more and less than 1°, 1° or more and less than 2°, 2° or more and less than 3°, ……14° or more and less than 15°), and calculate the area ratio per 1° to obtain the KAM of 1° or more and less than 4° in the field of view of 100μm×100μm as the measurement object The ratio of the area and the ratio of the area with KAM of 6° or more and less than 15°. Perform this measurement at any 5 locations and calculate the average value.

[Vickers hardness] The Vickers hardness is measured from the surface of the copper alloy material in accordance with the method specified in JIS Z2244 (2009). The load (test force) at this time was 2.9N, and the indenter time was 15 seconds.

[Deviation of resistance value] A small piece with a thickness of 0.2mm, a width of 2mm, and a length of 60mm is formed by stamping. Assuming the heat effect during assembly, heat treatment at 260°C for 30 minutes in an argon atmosphere is used to set the distance between the voltage terminals. The resistance value is measured by the four-terminal method of 30mm. The measurement was performed with n=500, and the standard deviation and average value were obtained from the results. The deviation of the resistance value is evaluated as "A" for the test material (copper alloy bar) whose value obtained by the mathematical formula of (standard deviation/average value×100) is 0.50% or less, which will exceed 0.50% and 0.55 The test materials below% are evaluated as "B", the test materials exceeding 0.55% and less than 0.60% are evaluated as "C", and the test materials exceeding 0.60% are evaluated as "D". And, if the value obtained by the mathematical formula of (standard deviation/average value×100) is 0.60% or less (that is, evaluation A to C), the deviation of the resistance value is evaluated as a pass level.

[Table 1]

It can be seen from Table 1 that the copper alloy strips of Examples 1 to 15 of the present invention contain 3% by mass or more and 20% by mass or less of manganese, and the average KAM measured by the backscattered electron diffraction method The value is 1° or more and less than 5°, which is within the appropriate range of the present invention. Therefore, even after the press forming and heat treatment at 260°C for 30 minutes, the variation in the resistance value is still small.

In contrast, it can be seen that the test material (copper alloy strip) of Comparative Example 1 contains 12% by mass of manganese, but the average value of KAM measured by the backscattered electron diffraction method is 0.5 °, that is, smaller than the appropriate range of the present invention. Therefore, after the press forming, heat treatment at 260°C for 30 minutes, the resistance value has a large deviation.

In addition, it can be seen that the composition of the test material (copper alloy strip) of Comparative Example 2 contains 12% by mass of manganese, but the average value of KAM measured by the backscattered electron diffraction method is 12.1°. That is, it is larger than the appropriate range of the present invention. Therefore, after the press forming and heat treatment at 260°C for 30 minutes, the resistance value varies greatly.

In addition, it can be seen that the composition of the test material (copper alloy strip) of Comparative Example 3 contains 7 mass% of manganese, but as the third heat treatment, it is heated at 700°C, which is measured by the backscattered electron diffraction method. The obtained KAM has an average value of 0.6°, which is smaller than the appropriate range of the present invention. Therefore, after the press forming and heat treatment at 260°C for 30 minutes, the resistance value varies greatly.

It can be seen that the test material (copper alloy bar) of Comparative Example 4 contains 10% by mass of manganese, but the average value of KAM measured by the backscattered electron diffraction method is 13.8°, which is the ratio The suitable range of the present invention is wider. Therefore, after the press forming, heat treatment is performed at 260°C for 30 minutes, the resistance value varies greatly.

It can be seen that the test material (copper alloy strip) of Comparative Example 5 contains 5% by mass of manganese, but the average value of KAM measured by the backscattered electron diffraction method is 0.9°, which is the ratio The suitable range of the present invention is wider. Therefore, after the press forming, heat treatment is performed at 260°C for 30 minutes, the resistance value varies greatly.

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Claims (8)

A copper alloy strip, the alloy composition of which contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The copper alloy strip is characterized by: The average value of the core average azimuth difference measured by the backscattered electron diffraction method is more than 1° and less than 5°. The copper alloy strip according to claim 1, wherein the value of the core average azimuth difference is 1° or more and less than 4° relative to the total area of the core average azimuth difference measured by the backscattered electron diffraction method The ratio of the area is more than 50%. The copper alloy strip according to claim 1 or 2, wherein the average azimuth difference of the core is 6° or more and less than the total area of the core average azimuth difference measured by the backscattered electron diffraction method The ratio of the area of 15° is 3% or more and 25% or less. The copper alloy strip according to any one of claims 1 to 3, wherein the Vickers hardness is 150 or more and 200 or less. The copper alloy strip according to any one of claims 1 to 4, wherein the alloy composition further contains one or more elements selected from the group consisting of: 0.01 mass% or more and 5 mass% or less of nickel; 0.01 mass% or more and 5 mass% or less tin; 0.01 mass% or more and 5 mass% or less of zinc; 0.01% by mass or more and 0.5% by mass or less of iron; 0.01% by mass or more and 0.5% by mass or less of silicon; 0.01% by mass or more and 0.5% by mass or less of chromium; 0.01% by mass or more and 0.5% by mass or less of zirconium; 0.01% by mass or more and 0.5% by mass or less of titanium; 0.01% by mass or more and 0.5% by mass or less of silver; 0.01% by mass or more and 0.5% by mass or less of magnesium; 0.01% by mass or more and 0.5% by mass or less of cobalt; and, 0.01% by mass or more and 0.5% by mass or less of phosphorus. A method for manufacturing a copper alloy strip, which is a method for manufacturing the copper alloy strip according to any one of Claims 1 to 5, and the manufacturing method is characterized in that it comprises the following steps: In the first heat treatment step, the copper alloy material having an alloy composition substantially the same as the alloy composition of the aforementioned copper alloy strip is heated in a high temperature region above 800°C and below 950°C; Thermal processing steps; The first cold working step of cold working with a high working rate of 50% or more, and the second heat treatment step of heating in a medium temperature region above 400°C and 700°C as a set of steps or more; In the second cold working step, cold working is performed at a low working rate of 5% or more and less than 50%; and, In the third heat treatment step, after reaching 200°C or higher and less than 400°C at a heating rate of 200°C/min or higher, hold for 10 to 55 seconds, and then cool to less than 50°C at a cooling rate of 100°C/min or higher . A resistance material for resistors, which uses the copper alloy strip according to any one of claims 1 to 5. A resistor having the resistive material described in claim 7.