JP2002363668A - Conductor for bending resistant cable and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductor for a bending resistant cable which has satisfactory tensile strength, elongation and electric conductivity, and also has satisfactory extra fine wire drawability, and a production method therefor. SOLUTION: The conductor for a bending resistant cable consists of a wire rod of a copper alloy, and is used for a cable requiring bending resistance. The conductor is obtained by forming a copper alloy obtained by incorporating In having purity of >=99.99 wt.% in a concentration range of 0.05 to 0.70 mass% and P having purity of >=99.99 wt.% in a concentration range of 0.0001 to 0.003 mass% into oxygen free copper having purity of >=99.99 wt.% into a wire rod.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor for a flexible cable and a method for manufacturing the same, and more particularly to a conductor used for a flexible cable such as a robot cable and a probe cable and a method for manufacturing the same.

[0002]

2. Description of the Related Art A copper alloy having high strength and high conductivity is generally used as a material of a conductor used in a flexible cable for electronic equipment, for example, a robot cable or a probe cable.

At present, as a copper alloy wire manufactured at a mass production level, there is a Cu—Sn alloy wire which can be continuously cast and rolled and is excellent in economy, and is used as a conductor material of a bending-resistant cable for electronic equipment. It has been heavily used. Further, other copper alloy wires are also applied to various fields according to the product cost and various characteristics of the copper alloy wire.

[0004] With the recent miniaturization and weight reduction of electronic equipment, the conductors of the electric wires used for these are also strongly required to be reduced in diameter, and conductors of φ0.03 mm or less are required. It is believed that the need for diameter reduction will further increase in the future.

[0005] The above-mentioned Cu-Sn alloy wire is formed of a copper alloy obtained by adding Sn to tough pitch copper as a base metal. Tough pitch copper is about 0.03mass oxygen
Since it is contained at a concentration of s%, tin oxide (about 3 μm in diameter) is dispersed in the base material of the Cu—Sn alloy wire. In the case where this Cu-Sn alloy wire is to be drawn into an ultra-fine wire having a size of φ0.03 mm or less, for example, φ0.016 mm, a problem occurs in that disconnection frequently occurs due to tin oxide.

To cope with this problem, a method has been adopted in which oxygen-free copper is used as a base material of a copper alloy, and the formation of tin oxide is minimized by adding Sn to the oxygen-free copper.

[0007]

However, Cu-
Continuous casting equipment (for example, SC) for producing Sn alloy wire
Since the R continuous casting and rolling equipment is a large-scale equipment, continuous casting and rolling are performed in the atmosphere, and it is difficult to completely suppress the formation of tin oxide. In the continuous casting process and the rolling process, equipment components (for example,
There is a possibility that refractory materials used for the furnace wall and the mold wall) may be mixed as foreign matter into the Cu-Sn alloy wire. Due to these causes, the ultrafine wire drawing when the Cu—Sn alloy wire is drawn into an ultrafine wire is reduced.

On the other hand, during the production of the Cu—Sn alloy wire, casting defects (blow holes) may be generated in the wire.
When rolling is performed on a wire having a blowhole therein to form a rolled wire, the blowhole may damage the surface of the rolled wire. Here, the blowhole formed in a portion close to the surface of the wire is broken during rolling, resulting in a surface defect. Also, the blowholes formed near the center of the wire rod, all the blowholes are completely crushed by rolling, and defects may disappear,
If the blowhole is not completely crushed, the gas remaining inside the defect will expand in volume during heat treatment at a high temperature, which is a subsequent process, or during coating or extrusion in a high temperature atmosphere when coating an insulator such as enamel. Rupture may cause surface defects. If surface defects caused by such blowholes occur during the intermediate heat treatment in the wire drawing process, they may cause wire breakage in the subsequent ultrafine wire drawing process, so that Cu-Sn is formed so that blowholes do not occur in the wire.
It is necessary to cast an alloy wire.

An object of the present invention, which has been made in view of the above circumstances, is that tensile strength, elongation, and electrical conductivity are good, and
An object of the present invention is to provide a conductor for a flexible cable having excellent ultrafine wire drawing properties and a method for producing the same.

[0010]

In order to achieve the above object, a conductor for a flexible cable according to the present invention is made of a copper alloy wire, and has a purity of 99% in a conductor used for a cable which is required to be flexible. More than 99% by weight of oxygen-free copper
0.05 to 0.70 of In with a purity of 99.99 wt% or more
mass%, P having a purity of 99.9 wt% or more is 0.000%.
A copper alloy formed in a concentration range of 1 to 0.003 mass% is formed on a wire.

According to the above arrangement, the desired tensile strength, elongation, and conductivity can be obtained by defining the purity of the base material constituting the copper alloy, the purity of the additive, and the concentration of the additive in the copper alloy. A conductor having a ratio can be obtained.

On the other hand, the method for manufacturing a conductor for a flexible cable according to the present invention uses a high-purity graphite crucible and has a purity of 99.
After dissolving 99 wt% or more of oxygen-free copper in a low-pressure atmosphere of 0.1 Pa or less, the atmosphere is replaced with an inert gas, and then the oxygen-free copper molten metal has an purity of 99.99 wt% or more of In and a purity of 99.9 wt%. % Or more of P, and the concentrations of In and P are 0.05 to 0.70 mass% and 0.0%, respectively.
001-0.003 mass% copper alloy melt is formed,
A copper alloy wire is formed using the molten copper alloy, and the copper alloy wire is subjected to cold drawing.

According to the above method, it is possible to obtain a high-quality conductor which is free from mixing of oxides of alloy elements and minute inclusions in the copper alloy.
The conductor has elongation and conductivity, and also has excellent fine wire drawability.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

The present inventors have found that the amount of decrease in conductivity due to the addition of In (contribution to the electrical resistivity of pure copper) is about 1/3 of the amount of decrease in conductivity due to the addition of Sn. Therefore, when the same amounts of In and Sn are added to copper as the base material, the Cu-In alloy wire is more conductive than the Cu-Sn alloy wire most conventionally used, while having approximately the same strength. That the rate is good (Japanese Patent Publication No. 62-102)
No. 88 and the like), and by including P together with In, attention has been paid to the fact that the occurrence of casting defects (blow holes) in a cast material when a copper alloy is formed by casting can be suppressed.

The conductor for a flexible cable according to this embodiment is obtained by adding oxygen-free copper having a purity of 99.99 wt% or more to a purity of 99.99 wt% or more.
0.05 to 0.70 mass of In of 9.99 wt% or more
s%, P having a purity of 99.9 wt% or more is 0.0001-
A copper alloy containing 0.003 mass% in a concentration range is formed into a wire having an outer diameter of 0.01 to 0.05 mm, and has a tensile strength of 784 MPa (80 kgf).
/ Mm ² ) or more, preferably 800 MPa or more, elongation of 0.5% or more, preferably 2.0% or more, and conductivity of 75% or more.
It has mechanical properties of not less than% IACS.

The outer diameter of the wire is preferably 0.05 mm or less from the viewpoint of reducing the diameter of the conductor, and is preferably 0.01 mm or more from the viewpoint of securing a desired tensile strength.

The size of the fine inclusions formed in the wire is preferably controlled to less than 3 μm (0.003 mm).

On the outer periphery of the wire, Sn-Pb solder, Ag,
It is preferable to form a plating film of Sn, Ni, or lead-free solder. This improves the corrosion resistance and solderability of the conductor.

Next, the operation of the present embodiment will be described.

In the present embodiment, oxygen-free copper having a purity of 99.99 wt% or more is used as the base copper. This makes it possible to prevent inclusion of inclusions (a cause of disconnection at the time of extra fine wire drawing) at the raw material stage, and also to prevent oxides (inclusions) of alloy elements during melting production and casting of the copper alloy. ) Can be reduced. Further, the purity of In and P added to oxygen-free copper is 9%.
9.99 wt% or more of In and P having a purity of 99.9 wt%
By using, the inclusion of inclusions at the raw material stage during melting and casting of the copper alloy can be prevented, and the generation source of oxides (inclusions) of alloy elements can be reduced.

The concentration of In is 0.05 to 0.70 mass.
By controlling the percentage, desired tensile strength, elongation, and electrical conductivity can be obtained. If the concentration is less than 0.05 mass%, it becomes difficult to obtain the desired tensile strength and elongation, and if the concentration exceeds 0.70 mass%, the electrical conductivity is significantly reduced. Here, a more preferable concentration of In is 0.15 to 0.40 mass%.

The concentration of P is 0.0001 to 0.003 m
By controlling ass%, it is possible to suppress the occurrence of casting defects (blow holes) in the cast material. The concentration is 0.
If it is less than 0001 mass%, the effect of reducing blowholes in the cast material cannot be expected, and the concentration is less than 0.1%.
If it exceeds 003 mass%, the decrease in conductivity due to solid solution of P becomes remarkable.

The size of the fine inclusions contained in the wire is 3
μm (0.003 mm) to control φ0.
Ultra-fine wire drawing at the level of 01 mm is possible. In general,
It is said that if a foreign matter having a size of １ ／ of the wire diameter is present in the wire, the foreign matter is likely to cause disconnection during the wire drawing process. Therefore, in the present embodiment, each material ( By controlling the purity and concentration of the metal element, the size of the fine inclusions in the wire is controlled to less than 3 μm, and φ
It enables ultra-fine wire drawing on the order of 0.0 lmm.

As described above, in the conductor according to the present embodiment, a tensile strength of 784 MPa or more (80 kgf / mm ² ), preferably 800 MPa or more can be obtained. Thereby, a sufficient breaking load can be obtained, and a sufficient bending life can be obtained. Further, in the conductor according to the present embodiment, 0.5% or more, preferably 2.
Elongation of 0% or more can be obtained. Accordingly, when the conductor is used as a conductor of a flex-resistant cable, the conductor does not break even when a bending strain is applied to the conductor, and a sufficient flex life can be obtained. Furthermore, in the conductor according to the present embodiment, a conductivity of 75% IACS or more can be obtained.
Thus, there is no possibility that transmission loss increases due to Joule heat at the time of energization, and the characteristics required for the signal line can be sufficiently satisfied.

Also, in the present embodiment, the description has been given of the conductor for the flexible cable. However, it is not limited that a plurality of conductors according to the present invention may be twisted (concentric twisting or collective twisting) into a stranded wire. Needless to say. It is needless to say that the conductor according to the present invention and a stranded wire using the conductor are used as an internal conductor, and a sheath or the like is provided on the outer periphery of the internal conductor, so that various cables may be used.

Next, a method of manufacturing the conductor for a flexible cable according to the present invention will be described.

A high-purity graphite crucible is placed in a vacuum chamber of a small continuous casting machine capable of vacuum melting,
The atmosphere in the vacuum chamber is adjusted to a low-pressure atmosphere of 0.1 Pa or less (almost a vacuum atmosphere).

Next, oxygen-free copper having a purity of 99.99 wt% or more is dissolved in a graphite crucible under a low-pressure atmosphere, and is maintained for a certain period of time. After that, an inert gas (eg, argon gas or nitrogen gas) is injected into the vacuum chamber, and the atmosphere in the vacuum chamber is replaced with an inert gas atmosphere.

Next, In with a purity of 99.99 wt% or more and P with a purity of 99.9 wt% or more are added to the oxygen-free copper melt in the graphite crucible under an inert gas atmosphere, and melting is performed.
The concentration of In and P is 0.05 to 0.70mas, respectively.
s%, 0.0001 to 0.003 mass% of a copper alloy melt.

Next, a rough drawn wire (copper alloy wire) is formed by using the molten copper alloy, and the rough drawn wire is subjected to cold drawing to have an outer diameter of 0.01 to 0.05 mm. Tensile strength is 784 MPa (80 kgf / mm ² ) or more, and elongation is 0.
A conductor having a conductivity of 5% or more and a conductivity of 75% IACS or more is produced. At this time, after performing the first cold drawing on the rough drawn wire and drawing to a desired diameter, the drawn material is subjected to at least one annealing treatment and cold drawing as needed. A conductor may be formed.

The purity of the graphite crucible used for melting is as follows:
Graphite concentration of 99.99 wt% or more, more preferably 9
It is preferably at least 9.999 wt%.

In the manufacturing method according to the present embodiment,
By using a high-purity graphite crucible when melting and manufacturing oxygen-free copper and a copper alloy, it is possible to prevent foreign substances from being mixed into the oxygen-free copper melt or the copper alloy melt from the crucible during melting.

Further, when dissolving and producing oxygen-free copper, 0.1%
By dissolving in a low-pressure atmosphere of 1 Pa or less, bubbles contained in (oxygen) in oxygen-free copper can be discharged and eliminated from the molten oxygen-free copper. As a result, the occurrence of blowholes in the cast material can be further reduced.

Further, when the copper alloy is produced by melting, the melting is performed in an inert gas atmosphere, whereby the generation of oxides (inclusions) of alloy elements in the copper alloy can be suppressed.

Further, for example, a rough drawing line of φ8 mm is drawn with φ0.
When trying to obtain a desired diameter by a single drawing process when drawing into an ultra-fine wire of 03 mm, the area reduction rate (99.9986%)
Becomes extremely large, and may reach the processing limit to cause disconnection. Therefore, in the manufacturing method according to the present embodiment, when the conductor is formed by performing the wire drawing process on the rough drawn wire, the wire drawing process is performed in a plurality of times, so that the wire drawing process per one time is performed. The reduction in area can be reduced, and the occurrence of disconnection during wire drawing can be prevented.

[0037]

EXAMPLE <Test 1> Graphite purity was 99.999 wt% in a vacuum chamber of a small continuous casting machine capable of vacuum melting.
And the atmosphere in the vacuum chamber is adjusted to approximately a vacuum atmosphere of 0.001 Pa.

Next, in a graphite crucible under a vacuum atmosphere, oxygen-free copper having a purity of 99.9999 wt% is dissolved to produce a molten oxygen-free copper, and the molten state is maintained for 5 minutes. After that, high-purity argon gas is injected into the vacuum chamber,
The atmosphere in the vacuum chamber is replaced with an Ar gas atmosphere.

In the oxygen-free copper melt in the graphite crucible under an Ar gas atmosphere, In with purity of 99.99 wt% and purity of 99.99 wt% were added.
Melting is performed by adding 9 wt% of P to form eight types of copper alloy melts having different concentrations of In, P, and oxygen, respectively, and using the copper alloy melts, a rough drawing wire of φ8 mm is produced ( Test pieces 1 to 3 (Example) and test pieces 4 to 8
(Comparative example)).

<Test 2> In a melting furnace of an SCR continuous casting and rolling apparatus, tough pitch copper having an oxygen concentration of about 0.03 mass% is melted to produce a tough pitch copper melt. Thereafter, to the tough pitch copper molten metal, In with a purity of 99.99 wt% and P with a purity of 99.9 wt% were added and dissolved, and In,
Two types of copper alloy melts having different concentrations of P and oxygen are formed, and a rough drawn wire having a diameter of 8 mm is manufactured using the copper alloy melts (test pieces 9 and 10 (comparative examples)).

<Test 3> In a melting furnace of an SCR continuous casting and rolling machine, tough pitch copper having an oxygen concentration of about 0.001 mass% is melted to produce a tough pitch copper melt. afterwards,
To the tough pitch copper melt, 99.99 wt% of pure In and 99.9 wt% of P are added and dissolved, and In,
Two types of copper alloy melts having different concentrations of P and oxygen are formed, and a rough drawn wire having a diameter of 8 mm is manufactured using the copper alloy melts (test pieces 11 and 12 (comparative examples)).

Table 1 shows the component concentrations of the test pieces 1 to 12 and the casting equipment used for the production.

[0043]

[Table 1]

Next, the structure of the longitudinal section of each of the test pieces 1 to 12 was observed using an optical microscope, and the presence or absence of alloy element oxides (inclusions) and casting defects (blow holes) in the structure was observed. . Further, after performing the first cold drawing on each of the test pieces 1 to 12 and drawing to φ0.9 mm, the drawn material is subjected to an annealing treatment for recrystallization, and the drawn material after the annealing treatment is applied to the drawn material. The second cold drawing is performed to produce an ultra-fine wire having a diameter of 0.016 mm. At this time, whether the wire can be drawn without breaking the wire over a length of 100 km or more,
The ultrafine wire drawing was evaluated. Table 2 shows these observation results and evaluation results.

Further, the tensile strength (M
Pa (kgf / mm ² )), elongation (%), and conductivity (% IACS) were measured. Table 3 shows the measurement results.

[0046]

[Table 2]

[0047]

[Table 3]

As shown in Tables 2 and 3, the test pieces 1 to 8 produced by using the small continuous caster were prepared by melting oxygen-free copper in a vacuum and then dissolving and manufacturing a copper alloy in an Ar gas atmosphere. Therefore, no oxide of the alloy element was observed in the alloy structure. On the other hand, the test pieces 9 to 12 produced by using the SCR continuous casting and rolling apparatus were prepared by dissolving tough pitch copper having a higher oxygen concentration in the atmosphere as compared with oxygen-free copper in the atmosphere, and then similarly using the copper alloy in the atmosphere. Oxide of alloy element was observed in the alloy structure due to melting production. Specifically, in the test pieces 9 and 10, In-Cu-
Many O-based compound particles and SiC particles having a particle size of about 8 μm were observed. In the test pieces 11 and 12,
SiC particles having a particle size of about 8 μm were observed.

The test pieces 1 to 4, 8, 9, and 11 are P
The concentration is within a specified range (0.0001 to 0.003 mass)
%), No blowholes were observed in the alloy structure. In contrast, test pieces 5 to 7, 10, 12
Since the P concentration was out of the specified range, blowholes were observed in the alloy structure.

As a result, the test pieces 1 to 4 and 8 exhibited good fine wire drawability because neither the oxide of the alloy element nor the blowhole was observed in the alloy structure. On the other hand, the test pieces 5 to 7, and 9 to 12 did not have good fine wire drawability because either the oxide of the alloy element or the blowhole was observed in the alloy structure.
Although there was a slight difference in the number of disconnections, disconnection occurred during drawing. Here, in Test pieces 5 to 7, no oxide of the alloying element was observed on the fractured surface of the broken portion, indicating that the disconnection was due to blow holes. In addition, test pieces 9 to
In No. 12, especially in the test pieces 9 and 11, no blowhole was observed in the fracture surface of the disconnection part, so it can be understood that the disconnection was caused by the oxide of the alloy element.

Next, test pieces 1-3, 5-7, 9-12
Means that the In concentration is within a specified range (0.05 to 0.70 mass).
%), The desired tensile strength, elongation, and conductivity were obtained. On the other hand, in the test pieces 4 and 8, the desired tensile strength or electrical conductivity could not be obtained because the In concentration was outside the specified range. Specifically, in test piece 4, I
Since the n concentration is 0.03 mass%, which is lower than the specified range, the tensile strength is 665 MPa (67.8 kgf / m
m ² ). In the test piece 8, since the In concentration was higher than the specified range of 0.90 mass%, the conductivity was as low as 71.0% IACS.

As described above, only the test pieces 1 to 3 produced by using the small-sized continuous casting machine had the In concentration, the P concentration and the oxygen concentration of the copper alloy within the specified ranges, and had no casting defects. In addition, oxides of alloy elements and inclusions such as crucible materials (furnace materials) do not mix with the cast material, and a high-quality cast material can be obtained. As a result, 784 MPa (80 kg)
f / mm ² ) or more, an elongation of 0.5% or more, and a conductivity of 75% IACS or more are obtained, and the fine wire drawability is also good.

As described above, the embodiments of the present invention are not limited to the above-described embodiments, and it is needless to say that various other embodiments are also conceivable.

[0054]

In summary, according to the present invention, the following excellent effects are exhibited. (1) The purity of the base material that constitutes the copper alloy, the purity of the additive,
And by specifying the concentration of additives in the copper alloy,
A conductor having the desired tensile strength, elongation, and conductivity can be obtained. (2) A high-quality conductor that is free from the risk of inclusion of oxides of alloy elements and minute inclusions in a copper alloy by melting and manufacturing the conductor of (1) under a vacuum atmosphere and an inert gas atmosphere. Can be obtained, and the conductor has an excellent fine wire drawing property.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 5/08 H01B 5/08 7/04 7/04 13/00 501 13/00 501D // C22F 1 / 00 625 C22F 1/00 625 630 630A 661 661A 685 685Z 686 686 (72) Inventor Akira Matsui 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture AA11 AA30 AB02 AB05 AB20 AD01 5G307 BA03 BB02 BC02 BC05 BC06 BC09 CA04 CB01 5G311 AB04 AD03

Claims (8)

[Claims] 1. A conductor which is made of a copper alloy wire and is used for a cable which is required to have bending resistance.
Oxygen-free copper of 9.99 wt% or more, purity 99.99 wt
% Of In 0.05-0.70 mass%, purity 9
P of 9.9 wt% or more is 0.0001 to 0.003 ma
A conductor for a bending-resistant cable, wherein a copper alloy containing ss% in a concentration range is formed in a wire. 2. The flexible cable conductor according to claim 1, wherein the size of the fine inclusions contained in the wire is less than 3 μm. 3. The wire has an outer diameter of 0.01 to 0.05 mm,
The flexible cable conductor according to claim 1 or 2, wherein the conductor has a tensile strength of 784 MPa or more, an elongation of 0.5% or more, and a conductivity of 75% IACS or more. 4. An Sn-Pb solder, A
The flexible cable conductor according to any one of claims 1 to 3, wherein a plated coating of g, Sn, Ni, or lead-free solder is formed. 5. A stranded wire formed by twisting a plurality of flex-resistant cable conductors according to any one of claims 1 to 4. 6. A cable comprising a conductor for a flexible cable or a stranded wire according to claim 1, and an insulating layer provided on the outer periphery of the conductor. 7. A highly pure graphite crucible having a purity of 99.
After dissolving 99% by weight or more of oxygen-free copper in a low-pressure atmosphere of 0.1 Pa or less, the atmosphere is replaced with an inert gas, and then In and 99.9 wt. % Or more of P, and the concentrations of In and P are 0.05 to 0.70 mass% and 0.0%, respectively.
001-0.003 mass% copper alloy melt is formed,
A method for manufacturing a conductor for a flex-resistant cable, comprising forming a copper alloy wire using the molten copper alloy and subjecting the copper alloy wire to cold drawing. 8. The method for producing a conductor for a flex-resistant cable according to claim 7, wherein after the copper alloy wire is subjected to cold drawing, annealing and cold drawing are repeated as necessary.