JP2019119929A - Copper alloy wire - Google Patents

Abstract

To provide a copper alloy wire that makes it possible to obtain a fine line that has excellent wire drawing properties, low conductivity, and high strength.SOLUTION: A copper alloy wire has a composition composed of a copper-based alloy that contains one additional element selected from the group consisting of Ni, Si, and Al with the balance being Cu and unavoidable impurities, and has a conductivity of 30%IACs or less, a tensile strength of 400 MPa or more and a line diameter of 8 mm or less.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a copper alloy wire.

  Conventionally, a wire made of a copper-based alloy (hereinafter referred to as a Cu-Ag alloy) containing silver (Ag) is used for a conductor wire for a heating element of a seat heater of an automobile (for example, background of Patent Document 1) Technology). Patent Document 1 discloses a wire made of a copper-based alloy containing Sn, Ni, and P (hereinafter, referred to as an SNP copper alloy) as a copper alloy wire not containing Ag.

JP, 2006-004750, A

  What is excellent in wire-drawing processability is desired as a raw material with low conductivity and a high-strength thin wire can be obtained.

  For example, a wire material having a low conductivity has a large electric resistance value, and thus easily generates heat by energization. In addition, a high strength wire rod is difficult to break when a load is applied to the wire rod by seating or the like, or it is difficult to be bent and plastically deformed. Furthermore, the thin line can reduce the feeling of foreign matter based on the wire at the time of sitting, etc., and an improvement in the feeling of use of the sheet with a heater can be expected. From these things, it can be said that a thin wire having low conductivity and high strength can be suitably used for a conductor wire for a heating element such as the above-mentioned seat heater. Alternatively, for example, a high-strength thin wire is not easily broken even when it is pulled during the installation, and can reduce the installation space and the installation space. Therefore, the thin wire with low conductivity and high strength is expected to be used for signal wires and the like provided in various wire harnesses and industrial robots.

  However, conventional wires such as the above-described Cu—Ag alloy wire and SNP copper alloy wire tend to have high conductivity if they are fine wires. When the concentration of additive elements such as Ag and Sn is increased to lower the conductivity, the wire drawability is poor.

  Here, conventionally, when plastic working such as wire drawing is further performed on a material subjected to plastic working in the manufacturing process of a copper alloy wire, heat treatment is performed before the next plastic working ( For example, Patent Document 1). By the heat treatment, the strain associated with the previous plastic working can be removed, and wire drawability can be enhanced. Also in the case of producing a thin wire, if the heat treatment is performed before and during the wire drawing process to remove the working distortion, the wire drawing processability can be enhanced. However, Ag-Cu alloy and SNP copper alloy are so-called precipitation type alloys. Therefore, in the Ag—Cu alloy and the SNP copper alloy, precipitates containing additive elements such as Ag and Sn are precipitated at the time of heat treatment. Even if such a heat-treated material is subjected to wire drawing, an increase in conductivity accompanied by the precipitation of the additive element is caused. If the content of the additive element is increased to reduce the increase in conductivity accompanying precipitation, coarse precipitates are likely to be formed during heat treatment. These coarse precipitates become the starting point of cracking, and breakage tends to occur at the time of wire drawing, resulting in deterioration of wire drawing workability.

  Then, this indication makes it an object to provide a copper alloy wire which is excellent in wire drawability, has a low conductivity, and can obtain a high-strength thin wire.

The copper alloy wire of the present disclosure is
A composition comprising one additive element selected from the group consisting of Ni, Si, and Al, with the balance being Cu and a copper-based alloy as an unavoidable impurity,
Conductivity is less than 30% IACS,
Tensile strength is 400MPa or more,
The wire diameter is 8 mm or less.

  The copper alloy wire of the present disclosure is excellent in wire drawability, and in addition, a thin wire having low conductivity and high strength can be obtained.

FIG. 1 is a graph showing the relationship between the heat treatment temperature (° C.) and the conductivity (% IACS) in Test Example 1. FIG. 2 is a graph showing the relationship between the heat treatment temperature (° C.) and the tensile strength (MPa) and the elongation at break (%) in Test Example 1. FIG. 3 is a graph showing the relationship between the degree of processing of wire drawing (-LN (A / A ₀ )) and the conductivity (% IACS) in Test Example 1. FIG. 4 is a graph showing the relationship between the degree of working of wire drawing (-LN (A / A ₀ )) and the tensile strength (MPa) in Test Example 1.

[Description of the embodiment of the present disclosure]
First, embodiments of the present disclosure will be listed and described.
(1) A copper alloy wire according to an aspect of the present disclosure is
A composition comprising one additive element selected from the group consisting of Ni, Si, and Al, with the balance being Cu and a copper-based alloy as an unavoidable impurity,
Conductivity is less than 30% IACS,
Tensile strength is 400MPa or more,
The wire diameter is 8 mm or less.

  The copper alloy wire of the present disclosure is made of a binary copper-based alloy in which the conductivity and the tensile strength satisfy the above-described ranges and that the above-described specific additive elements are contained. Such a copper alloy wire of the present disclosure has low conductivity and high strength, and is excellent in wire drawability as described below.

  Any of the above binary copper-based alloys is a so-called solid solution alloy as long as the above-mentioned specific range is satisfied. Therefore, the copper alloy wire of the present disclosure is a material to be subjected to wire drawing (hereinafter, may be referred to as a material for fine wire), and a predetermined temperature (before and during wire drawing) is given to the copper alloy material. Even if the heat treatment is performed in the following), the additive element remains in solid solution and does not substantially precipitate. From this point of view, the copper alloy wire of the present disclosure is substantially free from breakage due to coarse precipitates during wire drawing, and can be continuously subjected to wire drawing after heat treatment, and is excellent in wire drawability. In addition, since the copper alloy wire of the present disclosure has a tensile strength of 400 MPa or more, even if heat treatment is performed at a predetermined temperature to soften the wire, the strength capable of drawing can be ensured. Also from this point, the copper alloy wire of the present disclosure is excellent in wire drawability.

  Further, as described above, the conductivity does not substantially change before and after the heat treatment because the additive element is not substantially precipitated at the heat treatment. Therefore, the conductivity of the wire with the final wire diameter obtained by performing the wire drawing after the heat treatment can satisfy 30% IACS or less. Depending on the state of introduction of processing strain, the conductivity may be lower.

  By subjecting the copper alloy wire of the present disclosure to wire drawing and appropriate heat treatment as described above, a thin wire with low conductivity and high strength can be manufactured. Therefore, the copper alloy wire of the present disclosure can be suitably used as a material of a thin wire having low conductivity and high strength, for example, a conductor wire for a heating element such as a heat sheeter, a material such as a signal wire. In addition, since the copper alloy wire of the present disclosure is excellent in wire drawability, the above-described low-conductivity and high-strength thin line can be produced with high productivity, and contributes to mass production of the thin line.

(2) As an example of the copper alloy wire of the present disclosure,
An embodiment in which the additive element and the content thereof are any of the following may be mentioned.
Ni: 3.0% by mass or more and 10% by mass or less Si: 0.5% by mass or more and 4.0% by mass or less Al: 1.4% by mass or more and 8.8% by mass or less

  In the above embodiment, by using a copper-based alloy in which the content of the additive element satisfies the above range as a raw material, a copper alloy wire having a conductivity of 30% IACS or less and a tensile strength of 400 MPa or more can be easily manufactured. Excellent in manufacturability. The higher the content of the additive element in the above range, the lower the conductivity and the higher the strength. If the content of the additive element is below the lower limit of the above range, the conductivity tends to exceed 30% IACS.

(3) As an example of the copper alloy wire of the present disclosure,
Elongation at break is 0.3% or more and 5% or less,
There is a form in which the 0.2% proof stress is 400 MPa or more.

  In addition to the low conductivity and high tensile strength as described above, the above embodiment has high breaking elongation and 0.2% proof stress. Therefore, if the said form is a raw material for fine lines, it will be hard to break at the time of wire-drawing, and it will be excellent by wire-drawing workability.

Details of Embodiments of the Present Disclosure
Hereinafter, embodiments of the present disclosure will be specifically described.

[Copper alloy wire]
(Overview)
The copper alloy wire of the embodiment is typically used as a material of a conductor wire or the conductor wire itself, and is made of a specific binary copper base alloy. Specifically, the copper alloy wire of the embodiment contains one additive element selected from the group consisting of Ni (nickel), Si (silicon), and Al (aluminum), with the balance being Cu (copper) and the like. It has a composition comprising a copper-based alloy which is an unavoidable impurity. In addition, the copper alloy wire of the embodiment has a conductivity of 30% IACS or less, a tensile strength of 400 MPa or more, and a wire diameter of 8 mm or less. The details will be described below.

(composition)
The copper-based alloy forming the copper alloy wire of the embodiment is a binary copper-based alloy called a Cu-Ni alloy, a Cu-Si alloy, or a Cu-Al alloy. Each copper base alloy contains the additive element Ni, Si, or Al in a range where the conductivity is 30% IACS or less and the tensile strength satisfies 400 MPa or more.

  Ni is a total solid solution element with respect to Cu of the matrix phase. Therefore, the Cu-Ni alloy does not substantially form precipitates even if heat treatment is performed in the manufacturing process. Therefore, if the content of Ni is adjusted so that the conductivity is 30% IACS or less at the raw material stage, the product wire having a final wire diameter from the manufacturing process can be obtained, and the conductivity can be 30% IACS or less. For example, the content of Ni is adjusted in a range where the conductivity satisfies 30% IACS or less, and the production conditions such as the wire drawing degree and the heat treatment temperature are adjusted so that the tensile strength satisfies 400 MPa or more. By doing this, the copper alloy wire of the embodiment made of a Cu-Ni alloy can be manufactured.

  The copper alloy wire of the embodiment made of a Cu-Ni alloy is relatively easy to adjust component conditions and adjustment of manufacturing conditions such as heat treatment conditions, and is excellent in manufacturability. In particular, when the copper alloy wire of the embodiment made of a Cu-Ni alloy is used as a material for fine wires, it is easy to adjust the heat treatment conditions, and the conductivity is increased or broken due to the precipitates. There is virtually no. Therefore, in this case, a thin wire with a desired wire diameter can be manufactured with high productivity, and is excellent in mass productivity, which is preferable.

  Si and Al are elements which have a solid solution limit with respect to Cu of the matrix and exist in a solid solution state in a range of a predetermined temperature or less. Therefore, the Si content and Al content are adjusted so that the conductivity becomes 30% IACS or less at the raw material stage, and the heat treatment temperature is a temperature at which Si and Al do not precipitate when heat treatment is performed in the manufacturing process It will be described later). For example, the Si content and the Al content are adjusted in a range where the conductivity satisfies 30% IACS or less, and the wire drawing degree and the heat treatment temperature (but less than the precipitation temperature) such that the tensile strength satisfies 400 MPa or more Adjust manufacturing conditions such as By doing this, the copper alloy wire of the embodiment made of a Cu-Si alloy or a Cu-Al alloy can be manufactured.

  Even if the contents of Si and Al are smaller than Ni, the conductivity is low and the tensile strength tends to be high. At this point, the content of the additive element can be reduced.

The following is mentioned as an example of content of an additional element.
When it is a Cu-Ni alloy, the content of Ni is 3.0% by mass or more and 10% by mass or less.
When it is a Cu-Si alloy, content of Si is 0.5 mass% or more and 4.0 mass% or less.
In the case of a Cu-Al alloy, the content of Al is 1.4% by mass or more and 8.8% by mass or less.

If the lower limit is satisfied in the range of the content of the above-mentioned additive elements, the copper alloy wire made of each binary alloy has a conductivity of 30% IACS or less, and a tensile strength of 400 MPa or more, though it depends on manufacturing conditions etc. Easy to meet The higher the content of the additive element in the above range, the lower the conductivity and the higher the strength. When further low conductivity and high strength are desired, the content of the additive element may be, for example, as follows.
Content of Ni: 4.0% by mass or more, 5.0% by mass or more, 5.1% by mass or more, 5.3% by mass or more, 5.5% by mass or more, 6.0% by mass or more, 6.5 Mass% or more Content of Si: 0.6 mass% or more, 0.7 mass% or more, 0.75 mass% or more, 0.78 mass% or more, 0.8 mass% or more, 1.0 mass% or more, 1.5% by mass or more Content of Al: 1.5% by mass or more, 2.0% by mass or more, 2.2% by mass or more, 2.4% by mass or more, 2.6% by mass or more, 3.0% by mass % Or more, 3.5% by mass or more

If the upper limit value is satisfied in the above-mentioned range, the conductivity is not too low, and it is easy to use for a conductor wire and its material. In addition, since the strength is not too high and the wire drawing processability is excellent, it is easy to use as a material for thin lines. As long as the conductivity and the tensile strength satisfy the specific ranges described above, the content of the additive element may be reduced, for example, as follows.
Content of Ni: 9.5% by mass or less, further 9.0% by mass or less, 8.5% by mass or less Content of Si: 3.8% by mass or less, further 3.5% by mass or less, 3.0% by mass % Or less Content of Al: 8.5% by mass or less, further 8.0% by mass or less, 7.5% by mass or less

(Wire diameter)
The wire diameter of the copper alloy wire of the embodiment is 8 mm or less. If the wire diameter is 8 mm or less, it is easy to use for a conductor wire and its material, and also it is easy to manufacture a copper alloy wire itself. The wire diameter can be selected in the range of 8 mm or less according to the application and the like. As the wire diameter is smaller and thinner, the tensile strength tends to be higher due to the improvement of the strength by work hardening. In addition, the introduction of processing strain may lower the conductivity in some cases, and can be suitably used for a wire material for which low conductivity is desired.

  For example, in the case of using the copper alloy wire of the embodiment for a wire material, a relatively large diameter conductor wire, or the like, the wire diameter may be 0.3 mm or more and 8 mm or less. In particular, when the copper alloy wire of the embodiment is used as a material for fine wires, if the wire diameter is small to some extent, the amount of wire drawing to the final wire diameter can be reduced and the mass productivity of the fine wires is excellent. For example, in the case of using the copper alloy wire of the embodiment as a material for producing an ultrafine wire having a final wire diameter of 0.1 mm or less, the wire diameter is 3 mm or less, further 2.8 mm or less, 2.5 mm or less, It is good also as 1.5 mm or less and 1.0 mm or less. Alternatively, for example, in the case where the copper alloy wire of the embodiment is used for a conductor wire or the like with a relatively small diameter, the wire diameter may be 0.01 mm or more and 1.0 mm or less. Furthermore, the wire diameter may be less than 0.9 mm, and further 0.5 mm or less, 0.3 mm or less. A thin wire having a wire diameter of 1.0 mm or less can be suitably used as a conductor wire for a heating element, a signal wire or the like. In particular, the extremely thin wire having a diameter of 0.01 mm or more and 0.1 mm or less, further 0.08 mm or less, and 0.06 mm or less can be suitably used as a conductor wire for a heating element such as a heat theta of an automobile. If it is the said super-fine wire, it is because a foreign body feeling at the time of seating etc. can be reduced. Or the above-mentioned extra-fine wire can be suitably used for signal wires, such as a wire harness for cars. If it is the said ultra-fine wire, it is because a wiring space and an installation space can be reduced favorably.

(Characteristic)
<conductivity>
The conductivity of the copper alloy wire of the embodiment is 30% IACS or less. A copper alloy wire having a conductivity of 30% IACS or less can be suitably used for a conductor wire, a material thereof or the like for which a low conductivity or a high electric resistance value is desired. The conductivity can be selected in the range of 30% IACS or less according to the application and the like. For example, when the copper alloy wire of the embodiment is used for a conductor wire for a heating element or a material thereof, the electric resistance value can be increased as the conductivity is lower. Therefore, the conductivity may be 28% IACS or less, further 25% IACS or less, 20% IACS or less, 19% IACS or less, 18% IACS or less.

  On the other hand, when the copper alloy wire of the embodiment is used as a conductor wire for a heating element, a signal wire, or the like, or a material thereof, a certain degree of conductivity is desired. Therefore, the conductivity may be 10% IACS or more, and further 12% IACS or more, 15% IACS or more.

<Tensile strength>
The tensile strength of the copper alloy wire of the embodiment is 400 MPa or more. A copper alloy wire having a tensile strength of 400 MPa or more is excellent in strength and difficult to break. Further, the copper alloy wire tends to have high tensile strength even if it is softened by heat treatment. Therefore, the said copper alloy wire can be suitably utilized for the use etc. where high strength is desired.

  The tensile strength can be appropriately selected in the range of 400 MPa or more according to the wire diameter, the application and the like. When the copper alloy wire of the embodiment is used for a material such as a conductor wire for a heating element or a signal wire, for example, the wire diameter may be 2.5 mm or more, and the tensile strength may be 400 MPa or more, further 420 MPa or more. Alternatively, for example, the wire diameter may be 0.3 mm or more and less than 2.5 mm, particularly 0.3 mm or more and 1.0 mm or less, and the tensile strength may be 500 MPa or more, and further 550 MPa or more. As described above, the copper alloy wire having a high tensile strength can be improved in wire drawability by the heat treatment while having a strength capable of plastic working such as wire drawing even if heat treatment is applied and softened. Therefore, the said conductor wire etc. can be manufactured with sufficient productivity by utilizing the copper alloy wire to which heat processing was performed for the raw material for fine wires.

  Alternatively, when the copper alloy wire of the embodiment is used for a conductor wire for a heating element, a signal wire or the like, for example, the wire diameter may be 0.01 mm or more and less than 0.9 mm, and the tensile strength may be 750 MPa or more. A copper alloy wire having such a high tensile strength has a high fatigue limit, and is not easily broken even if repeated bending or the like is applied. Therefore, this copper alloy wire can be suitably used for applications such as a heat theta where loading of load, bending and the like are repeated. Alternatively, the copper alloy wire can be suitably used for applications such as a signal wire of a wire harness for an automobile installed in a narrow space, and a signal wire of a wire harness for a robot in which bending or the like is repeatedly performed. The higher the tensile strength, the higher the fatigue limit. Therefore, in the above application, the tensile strength may be 780 MPa or more, and further 800 MPa, 820 MPa or more, 830 MPa or more.

  There is no particular upper limit of tensile strength. For example, when the tensile strength is about 1000 MPa or less in the above-described material application and the like, the rigidity is not too high, and it is considered that wire drawing or the like is easily performed. In applications such as the above-mentioned conductor wire for heating element and conductor wire for wire harness, if the tensile strength is about 1000 MPa or less, the rigidity is not too high and it is considered that bending or the like is easy.

<Breaking elongation>
As an example of the copper alloy wire of the embodiment, it is mentioned that the breaking elongation satisfies 0.3% to 5%. In addition to the tensile strength satisfying the above range, if the breaking elongation satisfies the above range, it is not too hard nor too soft. Therefore, in the above-mentioned material use etc., it is hard to break in the middle of wire-drawing processing, wire-drawing processing can be performed continuously, and a thin wire can be manufactured with sufficient productivity. In applications such as the above-mentioned conductor wire for heating element and conductor wire for electric wire of wire harness, it is hard to break even if load, bending and the like are repeated as described above. From the viewpoint of preventing breakage, the elongation at break is preferably 0.5% or more, 0.8% or more, or 1.0% or more. In the use of the above-mentioned conductor wire etc., it is preferable that breaking elongation is 2.0% or more. From the viewpoint of suppressing the reduction in strength, the breaking elongation is preferably 4.8% or less, more preferably 4.5% or less, and 4.0% or less.

<0.2% bearing capacity>
As an example of the copper alloy wire of the embodiment, it is mentioned that 0.2% proof stress satisfies 400 MPa or more. If the 0.2% proof stress satisfies the above range in addition to the tensile strength satisfying the above range, the thin wire can be manufactured with high productivity in the above-described material application and the like. This is because breakage is difficult during wire drawing and wire drawing can be performed continuously. In applications such as the above-mentioned conductor wire for heating element and conductor wire for electric wire of wire harness, it is difficult to break even if a load is applied, pulled or bent, and these are repeated again. From the viewpoint of preventing breakage, the 0.2% proof stress may be set to 420 MPa or more, further 500 MPa or more, and 520 MPa or more. In the application of the above-mentioned conductor wire etc., 0.2% proof stress may be 700 MPa or more.

<Method of adjusting characteristics etc.>
In order to adjust the above-mentioned wire diameter, adjusting a wire-drawing degree is mentioned, for example.
In order to adjust the above-mentioned conductivity, for example, adjusting the content of the additive element can be mentioned.
In order to adjust the above-described tensile strength, elongation at break, and 0.2% proof stress, for example, adjusting the content of additive elements, the working degree of plastic working such as wire drawing, the heat treatment temperature and the like can be mentioned.

(Main effect)
The copper alloy wire of the embodiment is excellent in wire drawability by being made of a binary copper-based alloy containing a specific additive element while the conductivity and the tensile strength satisfy the specific range. Therefore, a low conductivity and high strength thin wire (for example, a wire diameter of 0.1 mm or less) can be manufactured with high productivity by subjecting the copper alloy wire of the embodiment to wire drawing and appropriate heat treatment. This effect is specifically described in Test Example 1 described later.

[Method of manufacturing copper alloy wire]
The copper alloy wire of the embodiment can be produced, for example, by a production method including the following steps.
(Casting step) A step of melting and casting a binary copper-based alloy containing one additional element selected from the group consisting of Ni, Si and Al.
(Primary processing step) A step of plastically processing the cast material produced in the casting step.
(Wire-drawing process) A process of subjecting the processed material that has undergone the primary processing process to wire-drawing.
(Heat treatment step) A step of subjecting a processed material subjected to plastic working in at least one of the primary working step and the wire drawing step to a heat treatment.
Each step will be described below.

(Casting process)
As described above, the content of the additive element in the binary copper base alloy of the raw material is adjusted in such a range that the conductivity in the wire with the final wire diameter is 30% IACS or more and the tensile strength 400 MPa or more. The specific content may be referred to the above (composition) section.

  The size of the cast material can be appropriately selected as long as a copper alloy wire having a wire diameter of 8 mm or less can be manufactured. Any suitable casting method can be used to manufacture the casting material. For example, a long cast material can be obtained by using various continuous casting methods such as a horizontal continuous casting method and an up-casting method. If a long continuous casting material is used, it is easy to manufacture a long wire drawing material. As a mold, one that does not react with copper such as carbon or an additive element can be used.

(Primary processing process)
The plastic working in this process includes plastic working other than wire drawing. For example, various processes such as swaging process and rolling process can be mentioned. By performing the primary processing without using the cast material as it is, casting defects can be reduced, or the processed material after the primary processing can be changed to a shape suitable for wire drawing.

(Wire drawing process)
In this process, wire drawing is performed on the processed material that has undergone the above-described primary processing process, or the processed material that has undergone the primary processing process and a heat treatment process described later, to a predetermined wire diameter. As for wire drawing, cold working can typically be used. For the specific wire diameter, refer to the above (wire diameter) section.

(Heat treatment process)
In this process, heat treatment is typically performed for the following purpose.
<Purpose of heat treatment> The strain introduced into the processed material by the plastic working performed in the primary working process and the wire drawing process is removed to make it easy to carry out the wire drawing after the heat treatment.
By this heat treatment, the processed material or the intermediate material in the middle of wire drawing is softened to improve wire drawability, and wire breakage becomes difficult, whereby wire drawing can be performed continuously. Therefore, the drawn wire material of a predetermined wire diameter can be manufactured with high productivity by performing the above-mentioned heat treatment.

  The heat treatment temperature may be selected in consideration of the composition of the copper base alloy used as the raw material, the degree of processing of wire drawing after the heat treatment, and the tensile strength at a predetermined wire diameter.

  For example, in the case of a Cu-Ni alloy, since substantially no precipitates are generated as described above, the tensile strength at a predetermined wire diameter is 400 MPa or more, and depending on the wire diameter, 500 MPa or more, further 750 MPa or more The heat treatment temperature may be selected in The heat treatment temperature in the case of a Cu-Ni alloy is, for example, 400 ° C. or more and 600 ° C. or less (see also Test Example 1 described later).

  The heat treatment temperature of a Cu-Si alloy or a Cu-Al alloy is selected in the range which a precipitate does not produce. That is, in addition to the above-mentioned composition, processing degree, and tensile strength, it selects in consideration of the solid solution limit. The heat treatment temperature when the content of Si is 4.0% by mass or less may be, for example, 200 ° C. or more and 400 ° C. or less. The heat treatment temperature when the content of Al is 8.8% by mass or less is, for example, 200 ° C. or more and 300 ° C. or less.

  The holding time depends on the composition of the copper base alloy and the heat treatment temperature, but may be, for example, 0.5 hours to 10 hours, and further 1 hour to 8 hours.

  The heat treatment can be performed any number of times after the primary processing step within a range that satisfies a tensile strength at a predetermined wire diameter of 400 MPa or more, and depending on the wire diameter, 500 MPa or more, and further 750 MPa or more. The relationship between the degree of processing after heat treatment and the tensile strength is determined in advance (see also the test example 1 described later), and the data is used to find that the conductivity is low and a predetermined wire diameter and a predetermined tensile strength are obtained. Easy to manufacture filling wire.

[Test Example 1]
Copper alloy wires composed of binary copper base alloys were prepared under various conditions, and the characteristics such as conductivity and tensile strength were examined.

(Examination outline)
In this test, a Cu-Ni alloy having a Ni content of 7.0% by mass was used as a binary copper base alloy. The drawn wire material whose wire diameter is 2.6 mm diameter was produced using the said Cu-Ni alloy. The properties of the drawn wire with a wire diameter of 2.6 mmφ in the non-heat-treated state and the properties in the heat-treated state at various temperatures were examined. The results are shown in Table 1, FIG. 1 and FIG.

  Further, in this test, the above-mentioned wire drawing material having a wire diameter of 2.6 mmφ is not subjected to heat treatment or is subjected to heat treatment, and further subjected to wire drawing (cold) to have a final wire diameter of 0.1 mm. Was produced. The characteristics of the wire of each diameter from 2.6 mmφ to 0.1 mmφ were examined. The results are shown in Table 2, FIG. 3 and FIG.

Here, as properties, conductivity (% IACS), tensile strength (MPa), elongation at break (%), 0.2% proof stress (MPa) were examined.
The conductivity (% IACS) was measured by the bridge method.
The tensile strength (MPa), 0.2% proof stress (MPa), and elongation at break (%) were measured using a general purpose tensile tester in accordance with JIS Z 2241 (Metal material tensile test method, 1998). .

(Sample No. 1 to No. 5)
A wire with a wire diameter of 2.6 mmφ was produced as follows.
The raw material Cu-Ni alloy was melt | dissolved and casted, and the wire diameter produced the cast material of 30 mm diameter.
The cast material was cut into a bar having a wire diameter of 24 mmφ, and swaging (primary processing) was performed to prepare a processed material having a wire diameter of 10.4 mmφ.
Wire drawing (cold) was performed on the processed material having a wire diameter of 10.4 mmφ until the wire diameter became 8.3 mmφ. The first heat treatment was performed after the wire drawing. After the first heat treatment, wire drawing (cold) was further performed to obtain a wire drawn material having a wire diameter of 2.6 mmφ. The first heat treatment conditions were a heat treatment temperature of 550 ° C. and a holding time of 3 hours.

  Sample No. 1 is a wire drawing material of the above-mentioned wire diameter of 2.6 mm diameter, and is a wire which has not given the following 2nd heat treatment. Sample No. 2 not subjected to the second heat treatment. 1 examined each characteristic at room temperature RT (here 25 degreeC).

  Sample No. 2-No. 5 is a heat treatment material obtained by subjecting a drawn wire with a wire diameter of 2.6 mmφ to a second heat treatment. The second heat treatment conditions were such that the heat treatment temperature was any of 400 ° C., 450 ° C., 500 ° C., and 550 ° C., and the holding time was 3 hours. Sample No. 2 subjected to the second heat treatment. 2-No. 5 examined each characteristic at room temperature RT after 2nd heat processing.

FIG. 1 is a graph showing the relationship between the heat treatment temperature (° C.) and the conductivity (% IACS). In this graph, the horizontal axis indicates the heat treatment temperature (° C.), and the vertical axis indicates the conductivity (% IACS).
FIG. 2 is a graph showing the relationship between the heat treatment temperature (° C.) and the tensile strength (MPa) and the elongation at break (%). In this graph, the horizontal axis indicates the heat treatment temperature (° C.), the left vertical axis indicates the tensile strength (MPa), and the right vertical axis indicates the breaking elongation (%).

(Sample No. 11 to No. 15)
Sample No. 12 to No. No.15 does not perform the following 3rd heat processing with respect to the above-mentioned wire drawing material (sample No. 1) of wire diameter 2.6mmφ, and performs wire drawing until it becomes the wire diameter (mm) shown in Table 2 It is the applied wire. Sample No. 11 is the sample No. 1 mentioned above. It is the same sample as 1. Sample No. 15 is a drawn wire with a final wire diameter of 0.1 mmφ. For each sample, each characteristic was examined at room temperature RT at each wire diameter (mm) shown in Table 2.

(Sample No. 21 to No. 25)
Sample No. 22-No. No. 25 was subjected to the following third heat treatment on the above-described wire drawing material having a wire diameter of 2.6 mmφ (sample No. 1), and then wire drawing to a wire diameter (mm) shown in Table 2 It is the applied wire. The third heat treatment conditions were a heat treatment temperature of 550 ° C. and a holding time of 3 hours. Sample No. 21 is the sample No. 1 mentioned above. It is the same sample as 5. Sample No. The numeral 25 is a drawn wire with a final wire diameter of 0.1 mmφ. For each sample, each characteristic was examined at room temperature RT at each wire diameter (mm) shown in Table 2.

FIG. 3 is a graph showing the relationship between the degree of processing (−LN (A / A ₀ )) and the conductivity (% IACS). In this graph, the horizontal axis indicates the degree of processing (-LN (A / A ₀ )), and the vertical axis indicates the conductivity (% IACS).
FIG. 4 is a graph showing the relationship between the degree of processing (−LN (A / A ₀ )) and the tensile strength (MPa). In this graph, the horizontal axis indicates the degree of processing (-LN (A / A ₀ )), and the vertical axis indicates the tensile strength (MPa).

With the degree of processing (-LN (A / A ₀ )), the cross-sectional area of the wire after heat treatment is A _0, and the cross-sectional area A of the wire of each wire diameter is a ratio of these cross-sectional areas (A / A ₀ ) It is a value represented by the natural logarithm (-log _e (A / A ₀ )) used.

Sample No. 11 to No. Sectional area A ₀ in 15 is a cross-sectional area of the wire of 8.3mmφ to a first heat treatment is performed. The cross-sectional area A of each sample is a cross-sectional area of a wire diameter of 2.6 mm, 0.91 mm, 0.45 mm, 0.2 mm, and 0.1 mm.
Sample No. 22-No. Sectional area A ₀ in 25 is a cross-sectional area of the wire of 2.6mmφ to a third heat treatment is performed. The cross-sectional area A of each sample is a cross-sectional area of a wire with a wire diameter of 0.91 mm, 0.45 mm, 0.2 mm, and 0.1 mm.
Sample No. Since the cross-sectional areas A ₀ and A of 21 are equal, the degree of processing is zero.

  As shown in Table 1 and FIG. 1, sample No. 1 comprising a Cu—Ni alloy which is a binary copper base alloy. 1 to No. It is understood that all the copper alloy wires of No. 5 satisfy the conductivity of 30% IACS or less. Here, the conductivity of any sample is almost equal, 25% IACS or less, 20% IACS or less, 18% IACS or less. From this, it can be said that the copper alloy wire made of this Cu-Ni alloy can have a conductivity of 30% IACS or less regardless of the presence or absence of heat treatment and the heat treatment temperature.

  As shown in Table 1 and FIG. 2, by performing the second heat treatment, while the tensile strength has a relatively high value of 250 MPa or more, the breaking elongation is as high as 40% or more, and the elongation is greatly improved. I understand. One of the reasons for this is considered to be that no precipitates are generated during the heat treatment, and in particular, breakage substantially does not occur due to coarse precipitates. Moreover, the copper alloy wire which consists of this Cu-Ni alloy has the intensity | strength which the further wire-drawing processing is possible, having high elongation. Therefore, it can be said that the copper alloy wire made of the above-described Cu-Ni alloy can be improved in wire drawability if heat treatment is performed at a temperature of 400 ° C. or higher.

  Sample No. 2 not subjected to the second heat treatment. In No. 1, the tensile strength is 400 MPa or more, and the breaking elongation is 0.5% or more. Such sample nos. It is understood that the wire drawing material of No. 1 can also be subjected to further wire drawing processing as described later, and can be used, for example, as a material for fine wire having a wire diameter of about 0.1 mm.

  As shown in Table 2 and FIG. 11 to No. 15, No. 21 to No. It can be seen that all the 25 copper alloy wires satisfy the conductivity of 30% IACS or less. Here, sample no. 11 to No. The conductivity of 15 is 25% IACS or less, further 20% IACS or less, 17.5% IACS or less, and is approximately equal. Sample No. 21 to No. The conductivity of 25 is even lower, less than 17.0% IACS, and approximately equal. From this, it can be said that the copper alloy wire made of the Cu-Ni alloy can satisfy the conductivity of 30% IACS or less regardless of the presence or absence of heat treatment and the degree of processing of wire drawing. As one of the reasons for this, it is considered that the binary copper base alloy containing Ni is a full solid solution type alloy and Ni does not precipitate in the manufacturing process or the like.

  As shown in Table 2 and FIG. It can be seen that a wire with a higher tensile strength can be obtained while further satisfying 30% IACS or less of electrical conductivity by further performing wire drawing without subjecting the wire drawing material of No. 1 to the third heat treatment (Sample No. 12 to No. 15). For example, sample No. 1 whose wire diameter is 0.91 mm. The tensile strength of 12 is 500 MPa or more. Also, for this sample no. In No. 12, the 0.2% proof stress is 500 MPa or more, the breaking elongation is 1.0% or more, and it is understood that the proof stress and the elongation are also excellent. Sample No. with smaller wire diameter. 13-No. In No. 15, tensile strength, 0.2% proof stress, elongation at break are sample No. It is understood that it is higher than 11 and excellent in mechanical characteristics. For example, sample No. 1 having a wire diameter of 0.1 mm. In No. 15, the tensile strength is 800 MPa or more, the 0.2% proof stress is 750 MPa or more, and the breaking elongation is 2.0% or more. As described above, sample No. 1 which is small in diameter, low in conductivity, high in strength and excellent in elongation. It is expected that No. 15 can be suitably used for conductor lines for heating elements, signal lines and the like. In addition, the influence of the dimensional effect can be considered as one of the reasons for the elongation at break to be excellent as the degree of processing increases.

  As shown in Table 2 and FIG. The sample No. 22 was also subjected to the third heat treatment to the wire drawing material of No. 1 and further subjected to wire drawing (sample No. 22 to No. 25). 12 to No. Similar to No. 15, it can be seen that while the conductivity satisfies 30% IACS or less, a wire having a tensile strength higher than that before the wire drawing can be obtained. Also, for sample no. 22-No. No. 25 is a sample No. 12 to No. Similar to No. 15, it is understood that the yield strength and the elongation are also excellent. For example, sample No. 1 having a wire diameter of 0.1 mm. In No. 25, the tensile strength is 750 MPa or more, the 0.2% proof stress is 650 MPa or more, and the breaking elongation is 1.5% or more.

Further, the following can be understood from the graph of FIG.
(1) The degree of processing and tensile strength are generally in proportion.
(2) Sample No. 1 not subjected to heat treatment. 11 to No. The graph of No. 15 and the heat treated sample No. 21 to No. The 25 graphs are almost parallel.
From this, sample No. Referring to the degree of processing of 15, it can be said that a copper alloy wire having a tensile strength of 750 MPa or more can be obtained by performing drawing processing with a degree of processing of 7 or more after heat treatment. Similarly, it can be said that a copper alloy wire having a tensile strength of 800 MPa or more, further 820 MPa or more, can be obtained by performing a wire drawing process with a working degree of 8 or more after heat treatment.

For example, it can be said that the following wire material can be obtained by performing a heat treatment after the heat treatment when the wire diameter is larger than 2.6 mm and performing wire drawing so that the degree of processing is 8 or more.
<Example 1> A wire having a wire diameter of 0.1 mm or more, further 0.3 mm or more, and a tensile strength of 750 MPa or more, further 800 MPa or more.
<Example 2> A wire having a wire diameter of less than 0.1 mm, for example, 0.08 mm or less, further 0.05 mm or less, and a tensile strength of 800 MPa or more, further 820 MPa or more. The 0.2% proof stress and elongation at break of this wire are as described in sample No. Expected to be higher than 25.

  Sample No. 1 having a wire diameter of 0.1 mm. As for No. 25, if wire drawing is further performed, it can be said that a wire having a wire diameter of less than 0.1 mm, for example, 0.08 mm or less and a tensile strength of more than 835 MPa can be obtained. It is expected that these smaller diameter wires (eg, 0.05 mm or less), low conductivity, high strength and excellent in elongation can be suitably used for conductor wires for heating elements (especially heat theta) and signal wires, etc. Be done.

The present invention is not limited to these exemplifications, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.
For example, in Test Example 1, the content of Ni, the wire diameter, the heat treatment temperature, and the like can be changed. Further, instead of Ni, a binary copper-based alloy containing Si or a binary copper-based alloy containing Al may be used.

Claims (3)

A composition comprising one additive element selected from the group consisting of Ni, Si, and Al, with the balance being Cu and a copper-based alloy as an unavoidable impurity,
Conductivity is less than 30% IACS,
Tensile strength is 400MPa or more,
Wire diameter is 8 mm or less
Copper alloy wire. The copper alloy wire according to claim 1, wherein the additive element and the content thereof are any of the following.
Ni: 3.0% by mass or more and 10% by mass or less Si: 0.5% by mass or more and 4.0% by mass or less Al: 1.4% by mass or more and 8.8% by mass or less Elongation at break is 0.3% or more and 5% or less,
The copper alloy wire according to claim 1 or 2, wherein 0.2% proof stress is 400 MPa or more.

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