JP2001295011A - Bending resistant copper alloy wire and cable using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new bending resistant copper alloy wire excellent in bending resistance and to provide a cable using the same. SOLUTION: An alloy wire rod of a Cu-Ag alloy, a Cu-Nb alloy, a Cu-Fe alloy or a Cu-Cr alloy is wire-drawn to a final wire diameter ϕof <=0.1 mm, and, after that, heat treatment is performed to control its tensile strength to >=450 MPa, elongation to >=4%, and electric conductivity to >=50% IACS. In this way, its tensile strength and elongation are made compatible in high dimensions, so that its bending resistance particularly in the high strain environment is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-thin bending-resistant copper alloy wire made of a copper alloy wire such as a Cu-Ag alloy and having a diameter of 0.1 mm or less, and a small-diameter cable using the same as a central conductor. is there.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of electronic devices, IC testers, medical devices, and the like, the diameter of cables applied to them has been reduced.

In general, cables used in these devices are required to have the same outer diameter as the conventional one and a larger number of wire cores in order to obtain flexibility and bending resistance. To this end, it is essential to reduce the diameter of the conductor (element wire), particularly the center conductor (φ0.1 mm or less).

Conventionally, conductors of cables satisfying such requirements include hard copper wires having excellent bending resistance and conductivity.
For example, a hard copper wire made of a Cu-0.3 wt% Sn alloy having a tensile strength of about 800 MPa, an elongation of 1 to 2%, and a conductivity of 80% IACS is used.

[0005] Recently, the tensile strength is 1000MP.
A so-called fiber-reinforced alloy (In-situ) wire made of a Cu-Nb alloy, a Cu-Ag alloy or the like exceeding a has been developed and put into practical use.

[0006] This fiber-reinforced alloy wire is prepared, for example, by adding Ag or the like to Cu in an amount of 6 wt% or more and then continuously casting it.
After precipitation of Ag and Cu by heat treatment to form an α + β phase and a eutectic structure, the precipitates are stretched by cold working and distributed in the form of fine fibers in the base material to greatly increase strength. It is known that it has a flex life of about 10 times or more than that of hard copper wire of pure copper (Showa Electric Cable Review; Vol.48, No.2 (1998) P
140).

[0007]

It is generally said that the bending life of a conductor made of copper or a copper alloy depends on the magnitude of bending strain applied to the conductor, but this is because bending strain is relatively small. This is true in the case (within the elastic strain region), and it is known that when the bending strain is relatively large (in the plastic strain region), the bending strain depends not only on the tensile strength but also on the elongation.

[0008] Therefore, when the bending strain is relatively large (plastic strain region), the bending life is longer when a wire having a certain degree of elongation is used than when using a hard copper wire having a high tensile strength. In the case of a conductor used in a plastic strain region, an alloy wire having both high tensile strength and high elongation is required.

Accordingly, the present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to achieve both high tensile strength and high elongation at the same time to greatly improve the bending resistance. And a novel flexible copper alloy wire and a cable using the same.

[0010]

In order to solve the above-mentioned problems, the present invention provides a Cu-Ag alloy,
A copper alloy wire rod of any one of a Cu-Nb alloy, a Cu-Fe alloy, and a Cu-Cr alloy is drawn to a final wire diameter of 0.1 mm or less in wire diameter, and then heat-treated to have a tensile strength of 450 M
It is a flex-resistant copper alloy wire having a Pa or more, an elongation of 4% or more, and a conductivity of 50% IACS or more.

That is, as described above, the bending characteristics of a copper wire or a copper alloy wire depend on the tensile strength, and the higher the tensile strength, the better the bending characteristics. In the case of (+ plastic strain), even if the tensile strength is large, if the elongation is small, the bending characteristics are inferior to the soft copper wire. For example, as shown in FIG.
When the bending characteristics of the hard copper wire and the soft copper wire are compared with each other, the bending characteristics of the hard copper wire are superior to those of the soft copper wire in a small region where the bending strain ε is about 3% or less. When ε exceeds about 3%, it can be seen that the bending characteristics of the soft copper wire are reversed and are superior to those of the hard copper wire.

Accordingly, the present invention provides a Cu-wire which is inherently a high-strength and high-conductivity copper alloy wire (hard material).
Ag alloy, Cu-Nb alloy, Cu-Fe alloy, Cu-C
Any alloy wire rod of r alloy is drawn to a final wire diameter of 0.1 mm or less in diameter, and then heat-treated to have a tensile strength of 450 MPa or more, an elongation of 4% or more, and a conductivity of 50% IACS or more. It is. As a result, since the elongation recovers even if the tensile strength is sacrificed to some extent, excellent bending characteristics (bending resistance) can be exhibited not only in a low strain region but also in a relatively high strain region.

[0013] More specifically, Cu- (1 to 15 wt%) Ag, Cu- (5 to
20 wt%) Nb alloy, Cu- (5-20 wt%) Fe
An alloy and a Cu- (5 to 20 wt%) Cr alloy are used, and after drawing these, as described in claim 6, heat treatment is performed while running in a tubular furnace heated to 500 ° C. or more. A flexible copper alloy wire can be easily obtained.

Further, as set forth in claim 7, the surface of the flexible copper alloy wire is further plated with any one of tin plating, silver plating, nickel plating, Sn-Pb solder plating, and lead-free solder plating. May be.

By using a single wire or a stranded wire of these bending-resistant copper alloy wires as the center conductor, excellent bending resistance can be obtained from a low strain region to a high strain region. A small-diameter cable having characteristics can be easily obtained.

[0016]

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

FIG. 1 shows an embodiment of a cable 1 according to the present invention.

As shown in the figure, the cable 1 has a center conductor 2 covered with an insulator 3 serving as an outer sheath.
A coaxial cable in which a shield wire (outer conductor) 4 for removing noise is coated around the insulator 3 and a jacket 5 serving as an outer coat is further formed around the shield wire 4 and has an outer diameter. Is a small diameter cable of, for example, 0.274 mm.

The center conductor 2 is extremely fine (for example, φ
(0.0254 mm), and has a stranded wire structure (42 AWG) in which seven strands 6 are twisted together.
84 mm.

Further, a solid fluororesin is used for the insulator 3 and its thickness is, for example, 0.06 mm. Further, the shield wire 4 has a wire diameter of about φ0.0254 mm, and is wound 24 times around the insulator 3. The material is Cu
-0.3wt% Sn alloy wire with tensile strength of 800MPa,
The elongation is 2% and the conductivity is 80% IACS. Further, the material of the jacket 5 is PET, and its thickness is, for example, 0.02 mm.

Each of the wires 6 constituting the central conductor 2
Is to draw a copper alloy wire of any one of a Cu-Ag alloy, a Cu-Nb alloy, a Cu-Fe alloy, and a Cu-Cr alloy to a final wire diameter of 0.1 mm or less and then heat-treat it. It is made of a bending-resistant copper alloy wire having a tensile strength of 450 MPa or more, an elongation of 4% or more, and an electrical conductivity of 50% IACS or more. Excellent bending characteristics (bending resistance) can be exhibited not only in the strain region but also in a relatively high strain region. Specifically, Cu- (1 to 15 wt%)
Ag, Cu- (5-20 wt%) Nb alloy, Cu- (5
-20% by weight) Fe alloy, Cu- (5-20% by weight) C
r alloy, and after ultrafine drawing of φ0.1 mm or less, 500
By performing the heat treatment while running in a tubular furnace heated to a temperature of not less than ° C., the intended flexible copper alloy wire can be easily obtained.

Here, the copper alloy wire is made of Cu-Ag alloy, C
The u-Nb alloy, Cu-Fe alloy, and Cu-Cr alloy are all limited to those having high electrical conductivity and having a final wire diameter of not more than 0.1 mm when ultra-fine wire drawing is performed. To obtain a tensile strength of 1000 MPa or more,
Even if heat treatment is performed thereafter, a decrease in tensile strength due to recovery of elongation can be suppressed, and electrical conductivity and tensile strength and elongation can be compatible at a high level (tensile strength of 450 MPa or more, elongation of 4% or more, conductivity of 50%). (IACS or more).

The reason why the tensile strength is set to 450 MPa or more is that if the tensile strength is smaller than that, pure copper soft copper wire or Cu-0.3w
This is because a sufficient improvement is not seen compared to the bending life of the soft copper wire of the t% Sn alloy. The reason why the elongation is set to 4% or more is to sufficiently satisfy the bending resistance under an environment where a relatively high strain is applied. In addition, the conductivity is 50%
The reason why it is set to IACS or more is that if it is less than IACS, the electrical properties as a conductive material are insufficient.

When a Cu-Ag alloy is used as the copper alloy wire, the optimal addition amount of Ag is in the range of 1 to 20 wt% as described above. That is, 1wt
When the content is less than 20% by weight, the strength is not sufficient. On the other hand, when the content is more than 20% by weight, the conductivity is lowered. It is. Also, Cu
As described above, the optimal amount of each additive element in the case of using a -Nb alloy, a Cu-Fe alloy, or a Cu-Cr alloy is optimally in the range of 5 to 20 wt%. That is, as in the case of the Cu-Ag alloy, if the content is less than 5 wt%, sufficient strength cannot be obtained. On the other hand, if the content exceeds 20 wt%, in addition to a decrease in conductivity, a remarkable casting defect tends to occur during casting. That's why.

On the other hand, as the heat treatment method, it is desirable to carry out the heat treatment while traveling in a tubular furnace heated to 500 ° C. or higher as described above. That is, other methods other than the method of running in a tubular furnace, for example, in a batch-type heat treatment method, in addition to the desired tensile strength and elongation characteristics are difficult to obtain, in addition to the finer the wire sticks to each other, the wire sticks, This is because the surface quality deteriorates. The heat treatment temperature is 500 ° C
If it is less than this, it takes a long time to obtain desired characteristics, and mass productivity is deteriorated.

The bending-resistant copper alloy wire obtained in this manner can be used as it is as the wire 6 of the center conductor 2, and the surface thereof is further plated with tin, silver, nickel or Sn-Pb solder. When any one of plating and lead-free solder plating is applied, discoloration of the surface of the wire 6 can be prevented, and the reliability at the time of connecting the cable terminal can be improved.

As shown in FIG. 2, the center conductor 2 has a wire 6 having a relatively large outer diameter (φ0.064 mm).
May be used as a single line as it is.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

(Example 1) First, oxygen-free copper (OFC) was melted using a high-frequency vacuum melting furnace, and then Ag was added in argon gas to prepare three types of Cu-Ag alloys (Cu-Ag).
2wt% Ag, Cu-5wt% Ag, Cu-10wt% Ag)
Was cast in the shape of a φ30 mm ingot. Next, these ingots are subjected to facing, cold-worked and drawn from φ28 mm to φ0.1 mm,
A running heat treatment was carried out at 600 ° C., and as shown in Table 1 below, samples (1-1,1-) having a tensile strength of 450 MPa or more, an elongation of 5% or more, and a conductivity of 50% IACS or more, respectively.
2, 1-3) was obtained.

Each of the samples thus obtained was subjected to a bending test under conditions (bending strain ε = 5%) under which a plastic strain was generated, and its characteristics were evaluated. Specifically, as shown in FIG. 3, a weight 7 is hung at the lower end of each sample 1 and its upper part is clamped by a bending jig 8, and the upper part is repeatedly bent alternately by 90 ° left and right. The flex life was evaluated based on the number of breaks.

EXAMPLE 2 Two kinds of Cu—Nb alloys (Cu-10 wt% Nb, Cu
-15wt% Nb) is cast in the form of φ30mm ingots, these ingots are subjected to facing, cold-worked and drawn from φ28mm to φ0.1mm,
Thereafter, a running heat treatment is performed at 600 ° C., and as shown in Table 1 below, each has a tensile strength of 450 MPa or more and an elongation of 5 MPa or more.
% And a sample having a conductivity of 50% IACS or more (2-1, 2
-2) was obtained.

Then, a bending test was performed under the same conditions as in Example 1 to evaluate its characteristics.

(Embodiment 3) Two kinds of Cu-Fe alloys (Cu-10wt% Fe, Cu
-15wt% Fe) is cast in the form of φ30mm ingots, these ingots are beveled, and drawn from φ28mm to φ0.1mm by cold working.
Thereafter, a running heat treatment is performed at 600 ° C., and as shown in Table 1 below, each has a tensile strength of 450 MPa or more and an elongation of 5 MPa or more.
% And a sample having a conductivity of 50% IACS or more (3-1, 3
-2) was obtained.

Then, a bending test was performed under the same conditions as in Example 1, and the characteristics were evaluated.

(Example 4) Two kinds of Cu-Cr alloys (Cu-10wt% Cr, Cu
-15wt% Cr) in the form of φ30mm ingots, face milling of these ingots, wire drawing from φ28mm to φ0.1mm by cold working,
Thereafter, a running heat treatment is performed at 600 ° C., and as shown in Table 1 below, each has a tensile strength of 450 MPa or more and an elongation of 5 MPa or more.
% Or more, and a sample having a conductivity of 50% IACS or more (4-1, 4
-2) was obtained.

Then, a bending test was performed under the same conditions as in Example 1, and the characteristics were evaluated.

Comparative Example 1 Four kinds of copper alloys (Cu-10 wt% Ag, Cu-15 wt) were prepared in the same manner as in Example 1.
% Nb, Cu-15 wt% Fe, Cu-15 wt% Cr) are cast in the form of φ30 mm ingots, these ingots are beveled, and cold-processed to φ28.
4 mm hardened copper wire (1 mm
After obtaining -1, 1-2, 1-3 and 1-4), a bending test was performed under the same conditions as in Example 1 to evaluate the characteristics.

Comparative Example 2 Two kinds of copper alloys (Cu-0.5 wt% Ag, Cu-0.
8 wt% Nb) was cast in the form of φ30 mm ingots, these ingots were subjected to face milling, drawn from φ28 mm to φ0.1 mm by cold working, and then subjected to running heat treatment at 600 ° C. As shown in FIG. 1, the tensile strength was 350 to 400 MPa and the elongation was 5
-10%, 90% IACS or more sample (2-1,2-
After obtaining 2), a bending test was performed under the same conditions as in Example 1 to evaluate its characteristics.

Comparative Example 3 Two types of copper alloys (Cu-30 wt% Nb, Cu-30 wt
% Cr) was cast in the shape of an ingot of φ30 mm to perform face milling, but a remarkable casting defect was found.

Comparative Example 4 Tough Pitch Steel (TPC), C
u-0.3wt% Sn alloy cast material is cold-worked
A hard copper wire is obtained by drawing from 8 mm to φ0.1 mm, and a part of the wire is annealed by running to obtain a copper wire as shown in Table 1 below.
Types of annealed copper wire (tensile strength 250-380MPa, elongation 1
(0% or more), a bending test was performed under the same conditions as in Example 1, and the characteristics were evaluated.

[0041]

[Table 1]

As a result, as shown in Table 1, all the samples of Examples 1 to 4 according to the present invention exhibited excellent bending characteristics.

On the other hand, in each of the samples of Comparative Example 1 which was not subjected to the heat treatment after the drawing, the tensile strength showed an excellent value, but the elongation was as low as 3% or less. Was significantly inferior.

Further, in each of the samples of Comparative Example 2 in which the concentration of the additive element was significantly lower than that of the present example, the elongation was excellent, but the tensile strength was as low as 400 MPa or less, and the bending was low. The characteristics were inferior to those of this example.

Further, in each of the samples of Comparative Example 3 in which the concentration of the additive element was higher than that of the present example, no remarkable casting defect was observed as described above, so that evaluation could not be performed.

Further, the sample of Comparative Example 4 which was not subjected to the heat treatment had a low elongation as in Comparative Example 1, so that the bending characteristics were significantly inferior to those of this Example.
In the heat-treated sample, the tensile strength was inferior as in Comparative Example 2, and the bending characteristics were low in all cases.

In Table 1, a sample having an elongation of 3% or less is H (hard copper wire), a sample having an elongation of 15% or more is material A (soft copper wire),
Those less than 4 to 15% were described as 1 / 2H (semi-hard copper wire). The bending characteristics of each sample were based on the bending life of the sample of Comparative Example 4-4. ○: 1.0 times or more and less than 1.5 times, Δ: 1.0
Those less than twice are indicated by x.

[0048]

In summary, according to the present invention, since the elongation is recovered while suppressing the decrease in the tensile strength as much as possible, the excellent bending characteristics (not only in the low strain region but also in the relatively high strain region). Flex resistance). The use of such ultra-fine copper alloy wire having excellent bending resistance as a conductor of a cable of a device having relatively large bending strain, such as a medical device, improves the life and reliability of the cable, and as a result, it is applied. It is possible to exhibit excellent effects such as greatly contributing to the high performance and high reliability of electronic and electrical equipment to be used.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of a flexible copper alloy wire according to the present invention and a cable using the same.

FIG. 2 is an enlarged sectional view showing another embodiment of the flexible copper alloy wire according to the present invention and a cable using the same.

FIG. 3 is an explanatory view showing a bending test method employed in this example.

FIG. 4 shows a Cu-0.3 wt% Sn alloy wire (φ0.08 m
It is a graph which shows the bending characteristic of m).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable 2 Center conductor 3 Insulator 4 Outer conductor 5 Jacket 6 Element wire (flexible copper alloy wire) 7 Weight 8 Bending jig

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 630 C22F 1/00 630F 630A 661 661A 682 682 685 685Z 686 686A 691 691B C25D 7/06 C25D 7 / 06 R H01B 1/02 H01B 1/02 A 5/02 5/02 A (72) Inventor Masayoshi Aoyama 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Pref. Hitachi Cable Co., Ltd. (72) Inventor Osamu Seya 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture F-term in the Hidaka Plant of Hitachi Cable, Ltd. 4E096 EA04 EA13 EA27 HA22 KA01 4K024 AA03 AA07 AA10 AA22 AB01 BA09 BB09 BC03 EA11 GA04 5G301 AA01 AA07 AA08 AA09 AA30 AB02 AB05 AD01 AE10 5G307 BA02 BB02 BC06 BC09 BC10

Claims (9)

[Claims] 1. A Cu—Ag alloy, a Cu—Nb alloy, Cu
-Fe alloy or Cu-Cr alloy, a copper alloy wire rod is drawn to a final wire diameter of φ0.1 mm or less, and then subjected to heat treatment to have a tensile strength of 450 MPa or more, an elongation of 4% or more, and conductivity. A flex-resistant copper alloy wire having a ratio of 50% IACS or more. 2. A Cu—Ag alloy having a purity of 99.
Cu obtained by adding 1 to 15 wt% of silver to pure copper of 9 wt% or more
2. The flex-resistant copper alloy wire according to claim 1, wherein a (-1 to 15 wt%) Ag alloy is used. 3. 3. The Cu—Nb alloy has a purity of 99.
The bending-resistant copper alloy wire according to claim 1, wherein a Cu- (5 to 20% by weight) Nb alloy obtained by adding 5 to 20% by weight of niobium to 9% by weight or more of pure copper is used. 4. The Cu—Fe alloy having a purity of 99.
Cu in which 5 to 20 wt% of iron is added to pure copper of 9 wt% or more
The flex-resistant copper alloy wire according to claim 1, wherein a-(5 to 20 wt%) Fe alloy is used. 5. The Cu—Cr alloy having a purity of 99.
The bending-resistant copper alloy wire according to claim 1, wherein a Cu- (5-20% by weight) Cr alloy obtained by adding 5-20% by weight of chromium to 9% by weight or more of pure copper is used. 6. The heat treatment comprises:
The bending-resistant copper alloy wire according to any one of claims 1 to 5, wherein the bending is performed while traveling in a tubular furnace heated to a temperature of not less than ° C. 7. The method according to claim 1, wherein the surface is further plated with any one of tin plating, silver plating, nickel plating, Sn—Pb solder plating, and lead-free solder plating. The flexible copper alloy wire described in the above. 8. A cable using a single wire of the flexible copper alloy wire according to claim 1 as a central conductor. 9. A cable comprising, as a central conductor, a stranded wire obtained by twisting a plurality of the bent copper alloy wires according to claim 1 as a central conductor.