JPH02304803A - Electrically conductive elastic cable conductor - Google Patents

Abstract

PURPOSE:To obtain the title conductor of great tensile strength sufficient to stand such stresses as flexure, torsion, tension, etc. by forming an alloy which contains 0.25 to 10wt.% of Cr and yet 0.001 to 3.0wt.% in the aggregate of Sn, Zr, Mg, Mn, Zn, etc., and which has the rest of contained elements, namely, Cu and P having its content restricted to less than 100ppm. CONSTITUTION:Cr grains drawn in the processing direction thereof are dispersedly arranged respectively in the base material of a conductor in the processing direction so as to raise the elasticity of the base material at a jump. P content exceeding 100 ppm of the base material causes the formation of an intermetallic compound consisting of Cr and P for decreasing the number of the Cr grains being drawn and for readily coarsening them to have a bad influence on the elasticity. The purpose of adding a group of specified elements including Sn to the base material is to improve strength, flexibility, heat resistance, etc. without having an influence on the act of drawing the Cr grains as the result of fusing Cr in a Cu radical and forming a Cr compound with Cu alone. Thus, the conductor being excellent in strength, conductivity and elasticity can be obtained at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a bend-resistant cable conductor for electrical conduction that requires strength, electrical conductivity, and bend resistance.

[Conventional technology]

Generally, annealed copper wire has been used as a cable conductor for automotive and electronic device wiring, but with factory automation (FA)
With the progress of office automation (OA), the proportion of movable cables in wiring materials has recently increased. So far, annealed copper wire has been used as such a movable cable conductor based on the same idea as before.

In recent years, there has been an increasing demand for conductors that have higher strength, electrical conductivity, and bending resistance than conventional TPC annealed copper wires as movable cable conductors for devices such as medical devices, floppy disks, and robots.

Medical device cables have complex movements, so
It is subjected to a combination of repeated stresses such as bending, torsion, and tension. In addition, since the head of the floppy disk cable moves laterally, it is subjected to complex repeated stress mainly caused by U-shaped bending.

[Problem to be solved by the invention]

So far, annealed copper wire has been used as the conductor of such movable cables based on the same idea as before, but due to the trend toward thinner conductors due to the weight reduction of cables, and furthermore, the automation of electronic device assembly lines1 Mechanization As a result, the loads such as tension, bending, and twisting on cable conductors have become greater than before, and the following problems have arisen.

With the recent trend toward thinner and lighter cable conductors, the strength of the conductors has decreased, making them more likely to break during assembly work. Furthermore, when a conventional annealed copper wire cable is used as a movable cable, its bending resistance is poor, so that the cable conductor may break due to fatigue during use.

Therefore, improvement measures have been taken such as making the twisting pitch of the stranded wire finer, but the effects have not been sufficient. In addition, due to the trend toward thinner conductors due to the reduction in the weight of cables, as well as the automation and mechanization of assembly lines for electronic equipment, the loads such as tension, bending, and twisting on cable conductors have become greater than before. It is desired to develop a conductor that is flexible, highly resistant to bending, and has high heat dissipation (electrical conductivity) in order to alleviate the heat generated by higher wiring densities.

Such equipment wiring conductors are required to have the following characteristics.

(1) It must have high tensile strength that can sufficiently withstand the combined repeated stress of bending, torsion, tension, etc.

(2) It must have high tensile strength to withstand automation of wiring and connections.

(3) The physical properties of soldering should not deteriorate due to the effects of heat over time.

(4) Soldering must withstand sharp bending at the base.

(5) Materials and processing costs are low, and the price is low.

[Failure to solve the problem]

In view of this, the present invention aims to use low-cost Cu alloy as a conductor for equipment wiring instead of phosphor bronze or copper-coated steel wire, which have high material and processing costs.

As a result of intensive research on flexibility, heat resistance, solder reliability, heat dissipation, etc., we have developed a flexible conductive cable conductor with excellent strength, conductivity, and bending resistance.

That is, in the present invention, CrO, 25 to IGv1% (hereinafter w1
% is abbreviated as %), and S n 0.001 to 0.
5%.

Zr 0.001~0.5%, Mg0.001~0
．． 5%.

Mn 0.001-0.5%, Zn 0.00
1-2.0%.

AIO, OQ1~0.5%, NiO,001~0
．． 5%.

F e O,001~G, 5%, T i Q, 0
01~[1,2%.

Co 0.001~0.5%, Cd Q, 001~
0.5%.

VO, 001~0.05%, Ag 0.001~0
．． 05%, InQ, OQ1~0.2%, Te
O, OQ1~[1,2%, YO, OQ1~0.05%,
Si Q, within the range of 001 to 0.01%, containing any one type or two or more types in a total of 0.001 to 3.0%,
A bend-resistant cable conductor for electrical conduction having Cr particles elongated in the processing direction, made of an alloy of unavoidable impurities with the balance Cu and P content limited to 1100 pp or less.

[Effect]

In the present invention, the Cr particles stretched in the processing direction are dispersed and arranged in the processing direction in the conductor base material, thereby dramatically increasing the bending resistance, and the thin rod-shaped Cr particles are uniformly dispersed. The more it is, the better the bending resistance will be. However, if the diameter of the elongated acne increases and the distribution density decreases, the bending resistance decreases.

The dispersion density is preferably about 102 to 106 particles/s (number of Cr particles per unit cross-sectional area).

However, the reason why the Cr content is limited to 0.25 to 10% is that the content is indispensable for forming the above-mentioned stretched Cr particles, and if it is less than the lower limit, satisfactory Cr particles cannot be obtained. This is because if the content exceeds the upper limit, it not only reduces cold workability but also does not improve bending resistance very much, which is not economical.

In addition, the P content in the inevitable impurities was limited to 1100 pp or less because if the P content exceeds Iooppm, an intermetallic compound between Cr and P will be formed, reducing the number of elongated Cr particles. This is because the wire tends to coarsen, which adversely affects the bending resistance, and also tends to cause breakage during wire drawing, which significantly impairs manufacturability. For the same reason, it is also desirable to limit the S content in the inevitable impurities to IOppm or less.

Furthermore, in the element group below Sn (hereinafter referred to as A element),
S n O, 001-I1.5%, Z ro, OQ
I ~0.5%, Mg0.001~0.5%, Mn
0.001-0.5%, ZnO, QOI ~2.0
%, A/0.0G1~05%, N i O,0
01~0.5%, FeO, [lD1~0.5%,
T i O,001-0.2%, Co O,00
1-0.5%, CdO, 001-0.5%,
VO, 001~0.05%, Ag 0.001~
0.05%, In 0.001-0.2%.

T e O, 001~0.2%, Yo, 001~0
．． Adding any one or more of them within the range of 0.001 to 0.01% in a total of 0.001 to 3.0% is because within these ranges, it is hard to solidify into the Cu base. Melt or
Alone or in compounds with Cu, Cr particles can form strength, flexibility, without affecting the elongation effect.

This is because although it improves heat resistance etc., if it is below the lower limit, no improvement will be seen by adding it, and if it is added above the upper limit, it will lower the electrical conductivity and greatly deteriorate the castability and hot workability. In particular, Si forms an intermetallic compound CrxSi and reduces the number of elongated Cr particles, making it impossible to improve the bending resistance, which is a feature of the conductor of the present invention.

The conductor of the present invention is made of Sn, 5n-Pb alloy, Ag, etc. in order to improve soldering properties and/or to prevent gas from having an adverse effect on the conductor during the formation of the insulation coating, and to reduce contact resistance.
Or coated with Ag alloy. However, if there are no such problems, coating with these metals or alloys is not necessary.

〔Example〕

An alloy having the composition shown in Table 1 was melted and cast into a mold without quenching to form an ingot 25 mm square and 300 mm long. 20m
The wire rod was made into a m-square shape, held at 900°C for 2 hours, and then hot-worked into a wire rod with a diameter of 8 mm. This was subjected to wire drawing and heat treatment to obtain a wire rod with a diameter of 1.6, which was further annealed using a running annealing furnace, and subsequently hot-dip plated with Sn to form a conductor. Annealing was performed at a temperature of 550°C in a N2 atmosphere,
The running speed of the line was 180 m/min.

Tensile strength, elongation, electrical conductivity, and bending fatigue strength of the Sn-plated conductor produced in this way.

We looked for solder wettability and manufacturing difficulty. These results are shown in Table 2 in comparison with conventional conductors made of 65/35 brass, 8% phosphor bronze, and tough pitch copper.

The bending fatigue strength is 70 on a test line that passes through the guide perpendicularly.
A load of g was suspended, the test line on the guide was bent horizontally from side to side, and the number of bends until breakage was determined. Bend to the right and return to the original position once.

I bent it to the left and brought it back down for a count of two.

The tensile strength was measured using an Instron type tester, with a gage distance of 1
00mm.

The conductivity was measured using the 4-terminal method, with a distance between gauges of 250 m and 20
The measurement was carried out in an oil bath at ℃.

Solder wettability was determined by immersing the product in a 5N-40% PB eutectic solder bath for 5 seconds and visually observing the wettability using a stereomicroscope.
Those with good wettability are marked with ○, those with slightly poor wettability are marked with Δ, and those with poor wettability are marked with X.

Regarding solder bondability, we soldered the test materials using 5N-40% PB eutectic solder and activated rosin as a flux, heated this in the atmosphere at 150°C for 1000 hours, and then observed the bonding interface. Those with no peeling are marked with a circle, and those with peeling are marked with an x.

In addition, the difficulty of manufacturing is evaluated based on whether wire breakage occurs during normal wire drawing during the manufacturing process, and those that are easy are marked with a circle.
Slightly difficult ones are marked with a Δ, and those that are difficult or difficult are marked with an X.

Composition conductor NcL Cr (%) A element group (
%) Conductor of the present invention 1 0.16 Sn
O,04,znO,42" 2 1.02 Z
r0.08. \IgO,ll〃3 1.87 AI
o, Q7. NiO, 12〃4 3.12 SnO
,24,Yo,007〃5 5.64 Mg0.0
3. ~! nO, 13〃6 8. Oznl, 3. Te
a, 007/17 1.13 FeO,23,Si
O,04〃8 1.24 Ti, (104,Ag(
1, [11〃9 1.04 Vo, 008. Zn
1.2〃10 1.84 Cod, 14, CdO,
10° comparison conductor 11 0.18 SnO,
04, MgO, lO/112 12.2 Fed, 3
4. Yo, 008〃13 1.31 Ti(1,
0311141, 11Vo, 14. In0.35 conventional conductor 15 Cu-352n (65/35 brass)
16 8% phosphor bronze 17 TPC (tough pitch cylinder) Table 1 Cr particle distribution P (ppm) S (ppm) 02
(ppm) Density (books/mm2) 8 2
3 10-10217
4 4 >10232
5 4 > 10257
3 5 > 10316
8 14 >103
71 8 15 >1
041544>t02 24 3 4 >10
219 3 3 >1
0'In0.013 9 2 5
>1021323>10 64 9 14>
104129 4 2
>102nd Strength Elongation Conductivity: Conductor NFL (kgf/mm2) (%) (
%z person 1 invention conductor 1 54,3
19. Q 76.8〃2 59.6
1? , 4 72.4〃362, I 16.
4 631゜〃4 65.4 16,2
58.1〃5 67J 16.3 56.3
” 6 72.5 15,555.!1〃7
59.4 1? , 5 70.8〃860,I
17.8 71.1〃9 58.7 17
．． 6 68.4” 10 56.0 17.
2 73.4 Comparison conductor II 37.2
20.0 87.4〃12 74.1 1
4,1 50.4〃13 56.7 10.1
? 0.0〃14 - - - Conventional conductor 15 48. l 15.3
25.0/116 47.7 2 &, 5 1
3.0〃17 26J 18.5 1002 front bending strength Solder leakage Solder joint
Manufacturing SS) (times)
Gender difficulty +09 0 0
01+2 0 0
△110 △ ○
X60×× △ 111× 50 0 × ×1st
As is clear from Table and Table 2, the conductors of the present invention Nα1~
10 are all compared with conventional conductors Nα15 to 17, strength,
It has excellent conductivity and bending strength, as well as good solder wettability and bonding properties.
It can be seen that it has excellent manufacturability and is suitable as a bend-resistant cable conductor for electrical conduction.

On the other hand, the comparative conductor Nα11 with a low Cr content has insufficient strength and bending strength, and the comparative conductor Nα11 with a high Cr content has insufficient strength and bending strength.
α12 had poor workability and was difficult to manufacture. Furthermore, the comparative conductor Nα13, which has a high P content, has poor bending strength, solder wettability, and bonding properties, and the comparative conductor Nα, which has a high content of A element group, has poor bending strength, solder wettability, and bonding properties.
No. 14 was able to be melted and cast, but it cracked significantly during hot working, and a test material could not be produced.

〔Effect of the invention〕

As described above, according to the present invention, a conductor with excellent strength, conductivity, and bending resistance can be obtained at a low cost, and can be used as a bending-resistant cable conductor for conductive use, as well as thinning of the conductor due to weight reduction, and assembly lines for electronic devices. It has remarkable industrial effects, such as facilitating automation and mechanization.

Claims (1)

[Claims] Contains Cr0.25-10wt% and further Sn0.001
~0.5wt%, Zr0.001~0.5wt%, Mg
0.001-0.5wt%, Mn. 0.001-0.5
wt%, Zn0.001-2.0wt%, Al0.00
1~0.5wt%, Ni0.001~0.5wt%, F
e0.901~0.5wt%, Ti0.001~0.2
wt%, Co0.001-0.5wt%, Cd0.00
1-0.5wt%, V0.001-0.05wt%, A
g0.001-0.05wt%, In0.001-0.
2wt%, Te0.001-0.2wt%, Y0.00
1~0.05wt%, Si0.001~0.01wt%
A total of 0.001 of any one or two or more types within the range of
Contains ~3.0wt%, balance Cu and P content is 100pp
A bend-resistant cable conductor for electrical conduction having Cr particles elongated in the processing direction and made of an alloy containing unavoidable impurities limited to less than m.