WO2014007258A1

WO2014007258A1 - Copper-alloy wire rod and manufacturing method therefor

Info

Publication number: WO2014007258A1
Application number: PCT/JP2013/068159
Authority: WO
Inventors: 司 ▲高▼澤; 聡勅使河原; 俊郎阿部; 修司富松
Original assignee: 古河電気工業株式会社
Priority date: 2012-07-02
Filing date: 2013-07-02
Publication date: 2014-01-09
Also published as: CN104169448A; JP5840234B2; EP2868757A4; KR101719888B1; EP2868757A1; KR20150030188A; CN104169448B; JPWO2014007258A1; EP2868757B1

Abstract

This copper-alloy wire rod and a manufacturing method therefor make it possible to inexpensively provide a copper-alloy wire rod that exhibits excellent strength, elongation, and conductivity and is suitable for use, for example, as a magnet wire. Said copper-alloy wire rod contains, by mass, at least 0.5% silver and at least 0.05% magnesium, with the remainder consisting of copper and unavoidable impurities, and exhibits a tensile strength of at least 350 MPa and an elongation of at least 7%.

Description

Copper alloy wire and method for producing the same

The present invention relates to a copper alloy wire and a method for manufacturing the same, and more particularly to an ultrafine copper alloy wire for a magnet wire and a method for manufacturing the same.

With the development of electronic equipment, miniaturization of electronic components has progressed, and the demand for ultrafine copper alloy wires (round wires) with a wire diameter of 0.1 mm or less is increasing. For example, a coil for a microspeaker used in a mobile phone, a smartphone, or the like is manufactured by winding an extra fine wire (magnet wire) having a wire diameter of 0.1 mm or less into a coil shape.

This winding processing requires toughness (elongation) as the workability that allows the formation of turns, and conventionally pure copper having excellent toughness has been used. However, although pure copper is excellent in electrical conductivity, it has a low strength, so there is a problem that fatigue resistance accompanying coil vibration is low.

In order to solve this problem, a technique using a high concentration Cu—Ag alloy containing 2 to 15 mass% of Ag that can increase the tensile strength without decreasing the conductivity is proposed (Patent Document). 1). In general, a processed metal or alloy has an increased tensile strength and a reduced elongation. However, when a heat treatment at a certain temperature or higher is applied thereto, the elongation is restored and the strength is decreased. In view of this, a technique has been proposed in which the strength and elongation are compatible even with a low-concentration alloy by performing the heat treatment temperature below the softening temperature (Patent Document 2). However, this method is difficult to control the heat treatment temperature and time. Regarding this point, 0.05 to 0.2 mass% Ag and 0.003 to 0.01 mass% Zr are added to copper to widen the softening temperature range and to achieve both strength and elongation. A technique for performing a softening process has been proposed (Patent Document 3).

JP 2009-280860 A Japanese Patent No. 3944304 Japanese Examined Patent Publication No. 4-77060

However, with the demand for longer magnet wire life and further miniaturization of the magnet wire (wire diameter 0.07 mm or less) due to further downsizing of electronic components, further enhancement of the strength of the copper alloy wire has been demanded. Yes. As described in Patent Document 1, when the Ag content is increased in order to increase the strength, on the other hand, the conductivity is lowered. Furthermore, Ag is an element that improves heat resistance, and heat treatment becomes difficult. Furthermore, since Ag is very expensive, the cost is significantly increased. Moreover, since the general solid solution type highly conductive alloy as described in Patent Document 2 has a narrow temperature range for realizing the semi-softening heat treatment, it is difficult to realize stable performance. Further, the method of semi-softening by adding a small amount of Zr to a low concentration Cu—Ag alloy (Patent Document 3) can easily achieve both elongation and strength, but is insufficient in terms of increasing the strength. Met.
Recently, the shape of the magnet wire is not limited to a round wire, and the use of a square wire or a flat wire is also being studied. Also in the case of these square wires and flat wires, it is required that the wire be thin enough to correspond to the diameter of the round wire.

The present invention has been made in view of the problems in the prior art, and an object thereof is to provide a copper alloy wire excellent in strength, elongation, and conductivity, for example, suitable for a magnet wire, at low cost. .

The present inventors diligently studied various copper alloys and heat treatment conditions in order to develop copper alloy wires suitably used for magnet wires and the like that are superior in strength, elongation, and conductivity compared to conventional alloy wires. . As a result, it has been found that when a Cu—Ag—Mg alloy wire is subjected to a semi-softening treatment, the elongation and strength are excellent, and the characteristics can be easily realized by heat treatment. The present inventors have thus obtained a copper alloy wire that is excellent in strength, conductivity, and elongation, for example, suitable for use as a magnet wire, by adding Ag and Mg to Cu in a predetermined composition and semi-softening treatment. I found out that The present invention has been completed based on this finding.

That is, according to the present invention, the following means are provided.
(1) A copper alloy wire containing 0.5% by mass or more of Ag and 0.05% by mass or more of Mg, the balance being Cu and inevitable impurities, a tensile strength of 350 MPa or more, and an elongation of 7% or more. .
(2) The copper alloy wire according to (1), which has a wire diameter of 0.1 mm or less (in the case of a round wire) or a wire thickness (in the case of a square wire or a flat wire).
(3) Said (1) or (2) whose Ag content is 0.5 mass% or more and 4.0 mass% or less, and whose Mg content is 0.05 mass% or more and 0.5 mass% or less The copper alloy wire according to Item.
(4) Said (1) or (2) whose Ag content is 0.5 mass% or more and 2.0 mass% or less, and whose Mg content is 0.05 mass% or more and 0.3 mass% or less The copper alloy wire according to Item.
(5) The above (1) to (1) further containing 0.05 to 0.3% by mass of at least one selected from the group consisting of Sn, Zn, In, Ni, Co, Zr and Cr. The copper alloy wire according to any one of 4).
(6) The copper alloy wire according to any one of (1) to (5), wherein the wire diameter or wire thickness is 50 μm or less.
(7) Cold work is performed on rough drawn wire of a copper alloy containing 0.5% by mass or more of Ag and 0.05% by mass or more of Mg, and the balance is Cu and inevitable impurities. A wire processing step for forming a wire having a thickness of 0.1 mm or less;
A method for producing a copper alloy wire, comprising a final heat treatment step for bringing the wire into a semi-softened state.
(8) The method for producing a copper alloy wire according to (7), wherein a heat treatment temperature in the final heat treatment step is 300 ° C. or higher and 600 ° C. or lower.
(9) The method for producing a copper alloy wire according to (7) or (8), wherein in the wire rod processing step, intermediate heat treatment is performed between a plurality of cold working operations.

Here, in the present specification, the semi-softened state means a state in which the elongation of the copper alloy wire satisfies 7% to 30%. Semi-softening treatment refers to heat treatment that gives the semi-softening state. The semi-softening temperature range refers to a heat treatment temperature in a range that gives a state where the copper alloy wire after the heat treatment satisfies elongation of 7% to 30%. On the other hand, the softening temperature refers to a heat treatment temperature that gives a state in which the tensile strength does not decrease any more in the copper alloy wire after the heat treatment. Referring to FIG. 3, the heat treatment temperature at which the slope becomes 0 (zero) in the tensile strength reduction curve is the softening temperature. The heat treatment temperature range refers to a temperature range in which a desired strength is maintained after the heat treatment in the semi-softening temperature range. However, when subjected to heat treatment at a high temperature exceeding this softening temperature (a temperature on the right side of the softening temperature in FIG. 3), the tensile strength is further reduced due to overheating.
On the other hand, the softened state means a state in which the elongation of the copper alloy wire has been recovered by exceeding 30%. The softening treatment refers to a heat treatment at a high temperature that gives the softened state.
In the present invention, the wire means a square wire or a flat wire in addition to the round wire. Accordingly, the wire of the present invention refers to a round wire, a square wire, and a flat wire unless otherwise specified. Here, the size of the wire is a round wire (the cross section in the width direction (TD) is circular), the wire diameter φ (the diameter of the circle in the cross section) of the round wire, and a square (the cross section in the width direction is a square). ) Is the thickness t and width w of the square wire (both are the same as the length of one side of the square of the cross section), and if it is a flat wire (the cross section in the width direction is rectangular), the thickness of the flat wire It refers to the length t (the length of the short side of the rectangle of the cross section) and the width w (the length of the long side of the rectangle of the cross section).

The Cu—Ag—Mg alloy wire of the present invention is suitable as, for example, a copper alloy wire for a magnet wire because it is excellent in tensile strength, elongation, and conductivity. In addition, since the performance can be exhibited with a small amount of Ag compared to a conventional Cu-Ag alloy wire with a large amount of Ag, it can be manufactured at a lower cost. Furthermore, according to the method for producing a Cu—Ag—Mg alloy wire of the present invention, since the temperature range for performing the semi-softening heat treatment is wide, a stable Cu—Ag—Mg alloy having excellent performance and less variation in performance. A wire can be manufactured.

It is a front view which shows typically the apparatus used for the test which measures the bending fatigue fracture number (number of repeated fractures) performed in the Example. FIG. 5 is a graph showing a comparison between the content of Ag and the tensile strength at the time of semi-softening for a comparative Cu—Ag alloy wire containing no Mg and a Cu—Ag—Mg alloy wire of the present invention containing Mg. is there. Cu-1% Ag-0.1% Mg with a wire diameter of 0.1 mm (where% means mass%, the same applies hereinafter) Changes in strength and elongation when a round wire is heat-treated at various temperatures FIG.

Hereinafter, the present invention will be described in more detail.
[Alloy composition]
In the copper alloy wire of the present invention, Ag is 0.5% by mass or more (preferably 0.5 to 4.0% by mass), and Mg is 0.05% by mass or more (preferably 0.05 to 0.5% by mass). And the remainder consists of Cu and inevitable impurities.
By adding Ag to Cu, the strength can be increased with almost no decrease in conductivity. Moreover, semi-softening heat treatment can be facilitated by improving heat resistance. The Ag content is 0.5% by mass or more, preferably 0.5 to 4.0% by mass, and more preferably 0.5 to 2.0% by mass. When Ag is too small, sufficient strength cannot be obtained. Moreover, when there is too much Ag content, while electroconductivity will fall, cost will become high too much. Furthermore, the heat treatment temperature becomes too high, and the heat treatment becomes difficult.
By adding Mg, the tensile strength at the time of semi-softening is improved, and an ultrafine magnet wire excellent in strength can be obtained. Further, the semi-softening temperature range is expanded, and the heat treatment temperature range for obtaining the characteristics required for the ultrafine magnet wire (tensile strength of 350 MPa or more and elongation of 7% or more) is widened, and stable production becomes possible. The Mg content is 0.05% by mass or more, preferably 0.05 to 0.5% by mass, and more preferably 0.05 to 0.3% by mass. When the Mg content is too small, the effect of increasing the strength during semi-softening and expanding the semi-softening temperature range is insufficient. Moreover, when there is too much Mg content, electroconductivity will fall remarkably.

In the copper alloy wire of the present invention, Ag is 0.5% by mass or more (preferably 0.5 to 4.0% by mass), and Mg is 0.05% by mass or more (preferably 0.05 to 0.5%). (Mass%), Sn, Zn, In, Ni, Co, Zr and Cr at least one selected from the group consisting of 0.05 to 0.3 mass%, with the balance being Cu and inevitable impurities An alloy composition consisting of

At least one element selected from the group consisting of Sn, Zn, In, Ni, Co, Zr, and Cr is an optional additive element in the copper alloy according to the present invention. In the present invention, the content of these elements is 0.05 to 0.3%, preferably 0.05 to 0.2% as each content. When this content is too small as each content, the effect of the strength increase by addition of these elements is hardly expected. Further, if the content is too large, the decrease in conductivity is too large, so that it is not suitable as a copper alloy wire such as a magnet wire.
These elements are solid solution strengthening type or precipitation strengthening type elements, respectively, and by adding these elements to Cu, the strength can be increased without significantly reducing the conductivity. This addition increases the strength of the copper alloy wire itself and improves the bending fatigue resistance.

[Physical properties]
The reason why the tensile strength of the copper alloy wire of the present invention is set to 350 MPa or more is that when it is less than 350 MPa, the strength when the diameter is reduced by wire drawing is insufficient, and the bending fatigue resistance is inferior.
Further, the reason why the elongation of the copper alloy wire of the present invention is set to 7% or more is that if it is less than 7%, the workability is inferior and problems such as breakage occur when the coil is formed.

[Production method]
The manufacturing method of the copper alloy wire of the present invention will be described.
As described above, the shape of the copper alloy wire of the present invention is not limited to a round wire, and may be a square wire or a flat wire, which will be described below.

[Manufacturing method of round wire]
First, the method for producing a copper alloy round wire according to the present invention includes, for example, casting, cold working (cold drawing), intermediate heat treatment (intermediate annealing), and final heat treatment (final annealing) in this order. . Here, when a copper alloy wire having desired physical properties can be obtained without being subjected to intermediate annealing, intermediate annealing may be omitted.

[casting]
Cu, Ag, and Mg raw materials are melted and cast in, for example, a graphite crucible, preferably made of carbon inside the casting machine (inner wall). The atmosphere inside the casting machine when melting is preferably a vacuum or an inert gas atmosphere such as nitrogen or argon in order to prevent the formation of oxides. There is no restriction | limiting in particular in a casting method, For example, a horizontal type continuous casting machine, an Upcast method, etc. can be used. By these continuous casting wire drawing methods, the steps from casting to wire drawing are continuously performed to cast a rough drawn wire having a diameter of usually about φ8 to 23 mm.
When not using the continuous casting wire drawing method, a billet (ingot) obtained by casting is subjected to wire drawing to obtain a rough drawing wire having a diameter of usually about φ8 to 23 mm.

[Cold working, intermediate annealing] (wire processing process)
By cold-working this rough drawn wire, it is processed into a thin wire having a diameter of 0.1 mm or less. As this cold working, it is preferable to cold-draw.
The processing rate in this cold working (drawing) varies depending on the target wire diameter, the copper alloy composition, and further the heat treatment conditions, and is not particularly limited, but this processing rate is usually 70.0 to 99.99. 9%.

When this cold working has a plurality of cold working steps of the first cold working (drawing) and the second cold working (drawing), the first and second cold working Intermediate annealing (intermediate heat treatment) may be performed during this period.
The heat treatment method for performing the intermediate annealing is roughly classified into a batch type and a continuous type. Batch-type heat treatment is inferior in productivity because it takes processing time and cost, but it is easy to control characteristics because temperature and holding time are easy to control. In contrast, continuous heat treatment is excellent in productivity because it can be performed continuously with the wire drawing process, but since heat treatment needs to be performed in an extremely short time, the heat treatment temperature and time are accurately controlled to stabilize the characteristics. It needs to be realized. Since each heat treatment method has advantages and disadvantages as described above, a heat treatment method suitable for the purpose may be selected.
In the case of the batch type, it is preferable to perform the heat treatment at 300 to 600 ° C. for 30 minutes to 2 hours in a heat treatment furnace in an inert atmosphere such as nitrogen or argon.
Examples of the continuous heat treatment include an electric heating method and an in-atmosphere heat treatment method. The electric heating method is a method in which an electrode ring is provided in the middle of the wire drawing process, a current is passed through the copper alloy wire passing between the electrode wheels, and heat treatment is performed by Joule heat generated in the copper alloy wire itself. In the in-atmosphere heat treatment method, a heating container is provided in the middle of wire drawing, and the copper alloy wire is passed through the heating container atmosphere heated to a predetermined temperature (for example, 300 to 600 ° C.) to perform heat treatment. Is the method. In any of the heat treatment methods, the heat treatment is preferably performed in an inert gas atmosphere in order to prevent oxidation of the copper alloy wire. In the case of the continuous type, since the heat treatment time is short, it is preferable to perform the heat treatment at 300 to 700 ° C. for 0.1 to 5 seconds.
By performing the intermediate annealing between a plurality of cold workings, the workability can be improved by recovering the elongation of the obtained wire. Moreover, Ag precipitation is accelerated | stimulated by intermediate annealing and the intensity | strength and electroconductivity of the wire obtained can be made higher.

[Finish annealing (also called final annealing)] (final heat treatment process)
The copper alloy wire processed to the desired size (wire diameter) by the above process is subjected to finish annealing as the final heat treatment.
As a heat treatment method for performing the finish annealing, a batch method and a continuous method can be used as in the case of the intermediate annealing.
During the finish annealing, depending on the composition and processing rate of the copper alloy wire, the tensile strength and elongation of the wire after the final heat treatment may change slightly. Therefore, in the present invention, the heating temperature and heating holding time in the finish annealing are appropriately adjusted so that the elongation of the copper alloy wire obtained by the final heat treatment is 7 to 30%, preferably 10 to 20%.
The final heat treatment is performed at a higher temperature when the heat treatment time is short, and at a lower temperature when the heat treatment time is long. In the case of the continuous type, since the heat treatment time is short, it is preferable to perform the heat treatment at 300 to 700 ° C. for 0.1 to 5 seconds. In the case of the batch method, the heat treatment time can be long, and it is preferable to perform the heat treatment at 300 to 600 ° C. for 30 to 120 minutes.

[Manufacturing method of flat wire]
Next, the manufacturing method of the copper alloy rectangular wire of the present invention is the same as the manufacturing method of the round wire, except that it has a rectangular wire processing step. Specifically, the method for producing a flat wire according to the present invention includes, for example, casting, cold working (cold drawing), flat wire working, and final heat treatment (final annealing) in this order. If necessary, intermediate annealing (intermediate heat treatment) may be inserted between the cold working and the rectangular wire working, as in the method for producing the round wire. The conditions of processing and heat treatment in each step of casting, cold working, intermediate annealing, and final annealing, and preferred conditions thereof are the same as in the method of manufacturing the round wire.

[Square wire processing]
Before flat wire processing, in the same way as the manufacture of round wire, cold work (drawing) is performed on the ingot obtained by casting to obtain a round wire-shaped rough drawing wire, and if necessary, intermediate annealing is performed. Apply. As the flat wire processing, the round wire (rough drawing wire) thus obtained is subjected to cold rolling with a rolling mill, cold rolling with a cassette roller die, pressing, drawing processing, and the like. By this flat wire processing, the cross-sectional shape in the width direction (TD) is processed into a rectangular shape to obtain a flat wire shape. This rolling or the like is usually performed by 1 to 5 passes. The rolling reduction and the total rolling reduction in each pass during rolling or the like are not particularly limited, and may be set as appropriate so that a desired rectangular wire size can be obtained. Here, the rolling reduction is the rate of change in the thickness in the rolling direction when flattening is performed, and the rolling reduction when the thickness before rolling is t ₁ and the thickness of the line after rolling is t _2. (%) Is represented by {1- (t ₂ / t ₁ )} × 100. For example, the total rolling reduction can be 10 to 90%, and the rolling reduction in each pass can be 10 to 50%. Here, in the present invention, the cross-sectional shape of the rectangular wire is not particularly limited, but the aspect ratio is usually 1 to 50, preferably 1 to 20, and more preferably 2 to 10. The aspect ratio (expressed as w / t below) is the ratio of the short side to the long side of the rectangle forming the cross-section (TD) cross section of the flat wire. As for the size of the flat wire, the thickness t of the flat wire is equal to the short side of the rectangle forming the width direction (TD) cross section, and the width w of the flat wire is the length of the rectangle forming the cross section of the width direction (TD). Equal to edge. The thickness of the flat wire is usually 0.1 mm or less, preferably 0.07 mm or less, more preferably 0.05 mm or less. The width of the flat wire is usually 1 mm or less, preferably 0.7 mm or less, more preferably 0.5 mm or less.
When this rectangular wire is wound in the thickness direction, high tensile strength, elongation, and electrical conductivity can be expressed as in the case of the round wire according to the present invention. Here, winding a flat wire in the thickness direction means winding the flat wire in a coil shape with the width w of the flat wire being the width of the coil.

[Manufacturing method of square wire]
Furthermore, when manufacturing a square wire, what is necessary is just to set so that the width direction (TD) cross section may become a square (w = t) in the manufacturing method of the said flat wire.

[Another Embodiment of Manufacturing Method of Wire Material]
As another embodiment of the method for producing a copper alloy wire according to the present invention, first, the rough drawn wire obtained by casting is subjected to first cold working (drawing), and then the elongation is recovered by intermediate annealing. Furthermore, the second cold working (drawing) may be performed to obtain a desired wire diameter or wire thickness, and finally, the entire manufacturing process may be adjusted to a predetermined mechanical strength and elongation by finish annealing. However, in terms of energy consumption and efficiency, it is preferable to reduce the number of cold working steps.
Each of the processing rates in the first and second cold wire drawing processes varies depending on the target wire diameter or wire thickness and copper alloy composition, as well as two heat treatment conditions of intermediate annealing and finish annealing. Although not particularly limited, the processing rate in the first cold working (drawing) is normally set to 70.0 to 99.9%, and the processing rate in the second cold working (drawing). Is 70.0 to 99.9%.

[Another Embodiment of Flat Wire and Square Wire Manufacturing Method]
Instead of the above manufacturing method, a plate material or strip material having a predetermined alloy composition can be manufactured, and these plates or strips can be slit to obtain a rectangular wire material or a rectangular wire material having a desired line width.
As this manufacturing process, for example, there is a method comprising casting, hot rolling, cold rolling, finish annealing, and slit processing. If necessary, intermediate annealing may be performed during the cold rolling. In some cases, the slit processing may be performed before the finish annealing.

[Heat treatment temperature range]
FIG. 3 shows changes in strength (tensile strength) and elongation when a Cu-1% Ag-0.1% Mg round wire having a diameter of 0.1 mm is heat-treated at various temperatures. If the heat treatment is performed at a temperature lower than the heat treatment possible temperature range, the strength is high, but the elongation does not sufficiently occur, so that a problem occurs when the coil is formed. In addition, when the heat treatment is performed at a temperature higher than the heat treatment possible temperature range, the elongation is increased, but the strength is greatly reduced, so that a problem occurs at the time of forming the coil, or the fatigue resistance is lowered and the life of the coil is reduced. . From the above, it can be seen that heat treatment in an appropriate temperature range is required in order to obtain a fine wire magnet wire having excellent characteristics. Further, in order to produce a copper alloy wire having stable performance by this semi-softening heat treatment, it is preferable that the temperature range of the semisoftening heat treatment is wide, and the copper alloy wire according to the present invention realizes this.

[Wire diameter or wire thickness, application]
Although there is no restriction | limiting in particular in the wire diameter of the copper alloy wire of this invention, or the thickness of a wire, Preferably it is 0.1 mm or less, More preferably, it is 0.07 mm or less, More preferably, it is 0.05 mm or less. The lower limit of the wire diameter or the wire thickness is not particularly limited, but is usually 0.01 mm or more in the current technology.
The use of the copper alloy wire of the present invention is not particularly limited, and examples thereof include a magnet wire that is an extra fine wire used for a speaker coil used in a mobile phone, a smartphone, and the like.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Examples of round wires, comparative examples]
The cast material contains 0.5 to 4.0% by mass of Ag, 0.05 to 0.5% by mass of Mg, and the balance of the example of the present invention having the alloy composition shown in Table 1 consisting of Cu and inevitable impurities. A Cu—Ag—Mg alloy and a copper alloy of a comparative example having the alloy composition shown in Table 1 were each cast into a rough drawn wire having a diameter of 10 mm by a horizontal continuous casting method. This rough drawn wire is subjected to cold working (drawing) (total working rate of the following first and second cold workings: 99.984%), intermediate annealing and finish annealing, and a round wire sample having a diameter of 40 μm is obtained. Produced. The heat treatment of intermediate annealing and finish annealing was performed in any of three patterns selected from batch annealing, current annealing, and running annealing, and each was performed in a nitrogen atmosphere. The intermediate annealing was performed only once between the first cold working (drawing) and the second cold working (drawing). As shown in Table 1, there are some that have been subjected to intermediate annealing and those that have not. Moreover, even in the appropriate heat treatment temperature range defined in the present invention, the balance between elongation and strength varies greatly depending on the heat treatment conditions. Therefore, the heat treatment conditions were adjusted so that the elongation was relatively close to 13 to 18%.

Examples of other round wires include at least one selected from the group consisting of optional additive elements Sn, Zn, In, Ni, Co, Zr and Cr in addition to Ag and Mg, with the balance being Cu and inevitable impurities A Cu—Ag—Mg— (Sn, Zn, In, Ni, Co, Zr or Cr) alloy of the present invention having the alloy composition shown in Table 2 and a comparative example having the alloy composition shown in Table 2 Were produced in the same manner as described above.

[Examples of rectangular wires, comparative examples]
In the same manner as the round wire, except that after roughing the wire (drawing), or after intermediate annealing, if it is performed, after performing rectangular wire processing, finish annealing, A flat wire sample was prepared. As shown in Table 3, there are those that have been subjected to intermediate annealing and those that have not. Moreover, even in the appropriate heat treatment temperature range defined in the present invention, the balance between elongation and strength varies greatly depending on the heat treatment conditions. Therefore, the heat treatment conditions were adjusted so that the elongation was relatively close to 13 to 18%.
As shown in Table 3, the flat wire processing is performed by cold rolling the wire diameter φ (mm) of the round wire before the processing into a flat wire having a size of width w (mm) × thickness t (mm). processed.

[Characteristic]
Various characteristics were tested and evaluated for the round wire and flat wire samples obtained as described above.
Tensile strength (TS) and elongation (El) were measured according to JIS Z2201 and Z2241.
The conductivity (EC) was measured according to JIS H0505.
Since the Ag content greatly affects the overall cost, the cost performance index CP is set to CP (MPa / mass%) based on 350 MPa, which is the tensile strength required for formability and bending fatigue resistance as an ultrafine magnet wire. ) = (Tensile strength of copper alloy wire-350) (MPa) / Ag content (mass%)
CP ≧ 20 is “◎ (excellent)”, 10 ≦ CP <20 is “◯ (good)”, 0 ≦ CP <10 is “△ (slightly inferior)”, and CP <0 is “× (inferior)”. ) ”.

The coil life was evaluated by measuring the number of bending fatigue fractures using the test method shown in FIG. As shown in FIG. 1, a copper alloy wire sample having a wire diameter φ or a wire thickness t of 0.04 mm (40 μm) is sandwiched between dies as a sample, and a 20 g weight (W )) And applied a load. In the case of a flat wire, the sample was set so as to be sandwiched between dies in the wire thickness direction (ND). The upper end of the sample was fixed with a connector. In this state, the sample was bent 90 degrees to the left and right, repeatedly bent at a rate of 100 times per minute, and the number of bending until breaking was measured for each sample. In addition, the number of bendings was counted as one round trip of 1 → 2 → 3 in the figure, and the interval between the two dies was set to 1 mm so as not to press the copper alloy wire sample during the test. The determination of breakage was made when the weight suspended at the lower end of the sample dropped. The bending radius (R) was set to 1 mm, 4 mm, or 6 mm depending on the curvature of the die. “◎ (excellent)” if the number of breaks is 201 times or more, “◯ (good)” if it is 151 to 200 times, “△ (somewhat inferior)” if it is 101 to 150 times, and less than 100 times Was evaluated as “× (poor)”.

As for the coil performance, those having a tensile strength of less than 350 MPa or an elongation of less than 7% are “x (poor)”, those having a tensile strength of 350 MPa to less than 370 MPa and an elongation of 7% or more are “◯ (good)”, tensile strength of 370 MPa or more and elongation. Those having a conductivity of 7% or more and a conductivity of 75% IACS or more were evaluated as “「 (excellent) ”.
Comprehensive evaluation is based on the above cost performance, coil life and coil performance, and it is "◎ (excellent)", then "○ (good)", "△" (Slightly inferior) ”and“ × (poor) ”.

The results of measuring and evaluating the characteristics of the sample of the present invention and the comparative example prepared in this way are shown in Tables 1 and 2 for round wires and in Table 3 for rectangular wires.

Also, for the comparative Cu—Ag alloy wire containing no Mg and the Cu—Ag—Mg alloy wire of the present invention containing Mg, the relationship between the Ag content and the tensile strength during semi-softening was measured. The result is shown in FIG.

2 and Table 1, when comparing the characteristics of copper alloy wires containing the same amount of Ag, the copper alloy wires of the present invention containing Mg have higher strength than the copper alloy wires of the comparative examples not containing Mg. . In addition, the copper alloy wire of the present invention is superior in balance between conductivity and strength to the conventional Cu—Ag alloy wire. From these, it can be seen that the copper alloy wire of the present invention can exhibit the same performance as the high concentration Cu—Ag alloy wire of the comparative example with a smaller Ag content, that is, at a lower cost. Focusing on the heat treatment temperature, the Cu—Ag—Mg alloy wire manufactured according to the manufacturing method of the present invention is approximately 50 ° C. compared to the Cu—Ag alloy wire having a higher strength than the comparative alloy wire having the same strength. It can be seen that the heat treatment can be performed at a low temperature, and the cost for the heat treatment can be greatly reduced.
Among the examples of the present invention, those with Ag of 0.5 to 2% by mass and Mg of 0.05 to 0.3% by mass have excellent cost performance and coil performance, and have more suitable properties as ultrafine magnet wires. I understand that

On the other hand, those in which at least one of the Ag content and the Mg content is insufficient as in Comparative Examples 1 to 5 cannot obtain sufficient strength even by semi-softening heat treatment, and are used as ultrafine magnet wires. Can not do it. Further, as can be seen from Comparative Examples 6 to 15, when the Mg content is less than 0.05% by mass, the effect of improving the semi-softening property by adding Mg can hardly be obtained. Of these, Comparative Example 7, Comparative Examples 9 to 12, and Comparative Examples 14 to 15 are comparative examples of alloy compositions that imitate Patent Document 1, respectively.
Further, Comparative Example 16 is a comparative example of the alloy composition imitating Patent Document 3 and Comparative Example 17 is that of Patent Document 2. However, the strength is insufficient, and at least one of cost performance and coil life is required. Inferior, the result was that it could not be used as an extra fine magnet wire.
Furthermore, Comparative Example 18 was a comparative example in which neither the intermediate annealing nor the finish annealing was performed, but the elongation was insufficient and the result was that it could not be used as an ultrafine magnet wire.

From Table 2, an alloy of Cu—Ag—Mg is obtained by adding at least one element selected from the group consisting of Sn, Zn, In, Ni, Co, Zr and Cr to the optional additive element Sn to Cu—Ag—Mg alloy. It can be seen that when the corresponding compositions are compared (for example, Example 101 for Example 2, Example 102 for Example 3, etc.), the tensile strength is improved.
Although not shown in the table, when the content of Sn among the optional additive elements is too large, the conductivity is inferior.

Also, from Table 3, it can be seen that the same results as in the case of the round wire were obtained in the case of the flat wire.

Table 4 shows magnet wire formability when the wire diameters of the present invention and the comparative Cu-Ag-Mg alloy wire (round wire) and the comparative Cu-Ag alloy wire (round wire) are variously changed. The results of the impact on “◎ (excellent)” indicates that no defects such as disconnection occurred when the copper alloy wire of each test material was formed into a coil, “○ (good)” indicates that disconnection occurred very rarely, and often The case where the disconnection occurred was evaluated as “Δ (slightly inferior)”, and the case where the coil could not be formed was evaluated as “× (inferior)”.

From the results of Table 4, when compared with a copper alloy wire having the same Ag content, the Cu—Ag—Mg alloy wire according to the present invention has a wire diameter larger than that of the Cu—Ag alloy wire of the comparative example. It can be seen that even if it is smaller, the coil can be formed without disconnection.
In the case of a rectangular wire, the same result as in the case of the round wire can be obtained.

Table 5 shows a Cu-Ag-Mg alloy wire according to the present invention and, as a comparison, a Cu-Ag alloy wire and a Cu-Ag-Mg alloy wire (both with insufficient Mg content) at various temperatures by a batch method. The result of having measured the heat treatment temperature range in which the heat treatment was performed for 30 minutes and the tensile strength of 350 MPa or more and the elongation of 7% or more could be achieved at the same time is shown. It can be seen that the Cu—Ag—Mg alloy wire according to the present invention has a heat treatment temperature range equal to or wider than that of the conventional high concentration Cu—Ag alloy wire for comparison, although the Ag concentration is low. Therefore, according to the present invention, the obtained Cu—Ag—Mg alloy wire can be easily subjected to a semi-softening treatment that can achieve both desired elongation and strength under a wider heat treatment temperature range. It can be seen that a stable product can be manufactured.

Claims

A copper alloy wire containing 0.5% by mass or more of Ag and 0.05% by mass or more of Mg, the balance being Cu and inevitable impurities, a tensile strength of 350 MPa or more, and an elongation of 7% or more.
The copper alloy wire according to claim 1, having a wire diameter or wire thickness of 0.1 mm or less.
The copper alloy wire according to claim 1 or 2, wherein the Ag content is 0.5 mass% or more and 4.0 mass% or less, and the Mg content is 0.05 mass% or more and 0.5 mass% or less. .
The copper alloy wire according to claim 1 or 2, wherein the Ag content is 0.5 mass% or more and 2.0 mass% or less, and the Mg content is 0.05 mass% or more and 0.3 mass% or less. .
Furthermore, 0.05 to 0.3% by mass of at least one selected from the group consisting of Sn, Zn, In, Ni, Co, Zr and Cr is contained as each content. The copper alloy wire according to Item.
The copper alloy wire according to any one of claims 1 to 5, wherein the wire diameter or the wire thickness is 50 µm or less.
The wire diameter or the wire thickness is determined by subjecting a rough drawn wire of a copper alloy containing 0.5 mass% or more of Ag and 0.05 mass% or more of Mg and the balance of Cu and inevitable impurities to cold working. A wire processing step of forming a wire of 0.1 mm or less;
A method for producing a copper alloy wire, comprising a final heat treatment step for bringing the wire into a semi-softened state.
The method for producing a copper alloy wire according to claim 7, wherein a heat treatment temperature in the final heat treatment step is 300 ° C or higher and 600 ° C or lower.
The method for producing a copper alloy wire according to claim 7 or 8, wherein in the wire processing step, an intermediate heat treatment is performed between a plurality of cold workings.