JPH01311508A - Material and manufacture of contact point - Google Patents

Abstract

PURPOSE:To obtain a material for a contact point excellent in transmission characteristics, welding property, and wear resistance by a method wherein a cast block of a crystalline structure made of monocrystals or crystals of metal or alloy arranged in one orientation is cold worked along the crystal orientation. CONSTITUTION:A mold 2 is heated by a heater 3 installed on its periphery to a temperature higher than the melting point of a solution 4. A coagulation shell of the solvent 4 is not generated inside the mold 2, and while a cast block 5 is cooled by a cooling device 7 installed at the exit, it is extracted by a pinch roll 6. This makes an organization of one-orientational coagulation. If oxygen free copper, Cu-35%Zn alloy or the like is solved and cast into a plate cast block in this device, the organization of the cast block contains few crystal grain boundaries which cross the cast block and is a crystalline structure of monocrystals or crystals arranged in one orientation where small particles of crystals extend lengthwise. If a contact point is made of this material, a contact point excellent in wear resistance and welding, having little contact resistance and high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to contact materials, and particularly improves signal transmission characteristics such as audio and video signals and weldability compared to conventional materials.

It has improved consumability and reduced contact resistance.

[Prior Art] Power cords for audio and video equipment such as stereo equipment and video equipment, precision measuring instruments, and electronic equipment such as computers are usually used through power strips. Brass hardwood has been mainly used as the contact material for power cords and power strips. In other words, the above-mentioned hard brass is harder than hard copper, so it has excellent springiness, and since the contact part is shorter than the cord, there is less voltage drop even if the conductivity is low, and it is easy to process. Because it has excellent properties and is cheaper than pure copper, it has rarely been used as a mainstream contact material.

In addition to the signal transmission contact materials used in these power cords and power strips, platinum is also used.

Silver, gold, etc. and alloys thereof are used as contact materials. However, these copper and platinum.

Contact materials such as silver and gold have conventionally been made by extrusion or rolling from ingots cast using cooling molds.

[Problem to be solved by the invention]

Weldability is one of the properties required for contact materials.

It has good consumability and low contact resistance. In conventional materials, the ingot is cast using a cooling mold and then extruded or rolled, so the ingot structure and the crystal structure after rolling are polycrystalline, and the surface of the material contains countless crystal grains. A world existed. In addition, in terms of contact materials for signal transmission, the development of conductors for cords between devices and within devices has progressed rapidly, and by using single crystal oxygen-free copper as a conductor for cords, noise generated from the conductor itself, such as signal Although the phase shift and signal attenuation have been largely resolved, noise or signal disturbance caused by stray capacitance at the contact point between the device's power cord and the outlet remains a problem. .

[Means to solve the problem]

In view of this, as a result of various studies, the present invention uses a material with excellent surface and internal quality as a contact material, and has superior signal transmission characteristics, weldability, and consumability than conventionally used brass contact materials. and its manufacturing method was developed.

That is, the material of the present invention is characterized by having a single crystal or unidirectionally aligned crystal structure of a metal or alloy material.

Further, the manufacturing method of the present invention is characterized in that a single crystal of metal or alloy or an ingot having a crystal structure aligned in one direction is cold-worked in the crystal direction.

[For production]

Conventional contact materials for signal transmission have a problem with the manufacturing method, and the countless crystal grain boundaries that exist on the material surface cause microscopic irregularities on the surface. In addition, surface and internal defects act as capacitance and resistance, further amplifying stray capacitance between devices. Additionally, a voltage drop occurs while passing through the contact materials of power cords and power strips, causing signal attenuation and phase disturbances throughout the connected equipment. First, conventional materials manufactured using water-cooled molds have a multidirectional solidification structure, which tends to cause surface cracks due to solidification shrinkage of the ingot, as well as internal defects such as shrinkage cavities and blowholes. , these defects remain even after being processed into a wire or plate and act as capacitance and resistance.

Second, in conventional materials, the capacitance component and resistance increase due to grain boundaries, which are a type of internal defect.

On the other hand, conventional general-purpose contact materials also have problems in their manufacturing methods, and the countless grain boundaries present on the material surface deteriorate weldability and wearability, and increase contact resistance.

That is, electric discharge occurs locally at some locations in the grain boundaries when the contact opens and closes, forming a powdery product that deteriorates weldability and wearability and increases contact resistance.

Against this! The present invention uses a single crystal with almost no surface or internal defects or a material with a unidirectionally aligned crystal structure, which reduces the capacitance component and resistance of the contact material, and reduces the phase shift of the signal. Prevent attenuation, etc. Alternatively, it generates discharge, improves stiffness, weldability, and wearability, and reduces contact resistance.

Materials with a single crystal or unidirectionally aligned crystal structure, that is, unidirectionally solidified ingots, start solidifying from within the ingot and the crystals grow in the longitudinal direction (the direction in which the ingot is pulled out), resulting in surface cracks and No shrinkage cavities or internal defects such as blowholes occur.

In addition, since grain boundaries occur only in the longitudinal direction of the ingot, workability is good, and intermediate annealing is not required, so recrystallization grain boundaries do not occur. Furthermore, since there are few grain boundaries, the degree of concentration of impurities at the grain boundaries is also small, reducing resistance. In addition, nodule grain boundaries on the ingot surface also exist only in the longitudinal direction, and since these grain boundaries are further stretched by cold working, there are extremely few grains on the material surface after working, and there are also few surface irregularities.

A method for manufacturing a long unidirectionally solidified ingot is heating the mold to a temperature higher than the melting point of the cast metal.

There are continuous mold casting methods (hereinafter abbreviated as OCC method) and mold vibrating horizontal continuous casting methods using water-cooled molds, but in order to easily produce ingots with a single crystal or unidirectionally aligned crystal structure, , the QCC method is advantageous.

〔Example〕

Example 1 A plate-shaped ingot was cast by the oCC method. Figure 1 shows an overview of the heated mold continuous casting equipment. This device consists of a casting furnace (1),
It consists of a mold (2), a cooling device (7) that cools the ingot (5), and pinch rolls (6) that pull out the ingot (5). Cast metal melted in a melting furnace (not shown) is introduced into a casting furnace (1) through a gutter. A heating element is built into the furnace wall of the casting furnace (1), and the cast metal is heated above its melting point and held as molten metal (4). This molten metal (4) enters the mold (2) and is cooled to form an ingot (5).
Then, it is pulled out by the pinch roll (6). At this time, the mold (2) is heated above the melting point of the molten metal (4) by the heating device (3) installed around the mold, so the molten metal (4) does not form a solidified shell on the inner surface of the mold (2). First, the ingot is cooled via the ingot by the cooling device (7) set at the outlet of the mold (2), resulting in a unidirectionally solidified structure.

With this equipment, oxygen-free copper, CLI-35% Zn alloy, C
U-4%3N-0,01%P alloy was melted and cast to a thickness of 2
A plate-shaped ingot with a size of 0 and a width of 200# was obtained. The structure of this ingot was a single crystal structure in which there were almost no grain boundaries crossing the ingot, and a small number of crystal grains extending in the longitudinal direction, or a crystal structure arranged in one direction.

These materials were rolled to a thickness of 0.8 m only by cold rolling, and then cut and molded to produce contact parts for power plugs and table taps made of the members of the present invention. It was assembled into a plug and a table tap as shown in Figure 3. In Fig. 2, 8 and 9 are contact parts that are components of the power plug, 10 is an insulating case, 11 is an insulator for the cord attached to the power plug, 12, 13
indicates a conductor, and in Fig. 3, 14.15 is a contact part that is a component of a power strip, 16 is an insulating case,
17 is the insulator of the cord attached to the power strip;
18 and 19 are conductors.

In addition to examining the material characteristics of these contact parts, we evaluated the acoustic characteristics and image clarity of the equipment when power plugs and power strips were used for signal transmission, and compared the results with conventional materials. Shown in the table.

Conventional members include the oxygen-free copper, CLJ-35%Z
Regarding n alloy, Cu-4%3n-0,01%P alloy,
Thickness: 100 mm, width: 200 mm, cast using a conventional water-cooled mold
mm thick ingot by hot rolling to a thickness of 20 m and a width of 200 mm.
After forming a plate material of 0.8 m in thickness and 200 mtn in width, intermediate annealing and cold rolling were performed. This was cut and molded into contact parts for power plugs and power strips, which were assembled into the power plugs and power strips shown in FIGS. 2 and 3 in the same manner as described above.

The electrical conductivity in Table 1 is the measurement result for a plate material (processed material) with a thickness of 0.8#, and the strength is determined by a tensile strength of 40%.
/rruA or less is marked Δ, 40-60Kg/rtv
Those of A are marked with Q, and those of 60 Kg/mrA or more are marked with ◎.

As is clear from Table 1, when comparing the same materials, it can be seen that the members Nα1-3 of the present invention are all superior in signal transmission characteristics for audio and video than the conventional members Nα4-6. In particular, the inventive member Nα1 made of oxygen-free copper has much better signal transmission characteristics for audio and video than the currently used conventional members No. 5 made of brass (Cu-35% ZN alloy), and The voltage drop across the area is also reduced due to the high conductivity. The conventional member Nα4 made of oxygen-free copper had low strength and was therefore unsuitable as a contact material, but since the member Nα1 of the present invention is processed only by cold working, its strength is equivalent to that of the conventional member Nα5 made of brass. It is suitable as a contact material for signal transmission.

Example 2 Oxygen-free copper, AU, A9-15%Cu
The alloy and Pt are melted and cast to a thickness of 20! nIr1,
A plate-shaped ingot with a width of 200 mm was obtained. The structure of this ingot is
There were almost no grain boundaries crossing the ingot, and the structure was a single crystal with a small number of crystal grains extending in the longitudinal direction or a crystal structure arranged in one direction. This ingot was rolled to a thickness of 0.8m by cold working only, and then 10#1Ill
A sample of X10 shoes was cut out and a glow discharge test was performed.
The amount of wear of the contacts after 106 disconnections was measured, and the results are shown in Table 2 in comparison with conventional members. Here, it is assumed that the battery is 30 cm, the steady current is 0.4 A, and the induction period is 3 days.

Conventional members include the above-mentioned Au, Ag-15%Cu, pt
A thickness of 100a cast using a conventional water-cooled mold.
i, an ingot with a width of 200 rrm is hot rolled to a thickness of 20 rrm.
After forming a plate material with a width of 200 mm and a width of 200 mm, it was subjected to intermediate annealing and cold rolling to a thickness of 0.8711I11. It was made into a plate material with a width of 200 m. A sample of 1 hll x 10 Jlll11 was cut out from this plate material.

Further, regarding the above alloy, the static welding limit current and 6V,
The contact resistance after IOS opening/closing was measured under the conditions of 1A and L=24mH, and the results are shown in Table 2 in comparison between the inventive material and the comparative material.

As can be seen from Table 2, all of the materials of the present invention have a smaller amount of wear than the conventional materials and have good wearability. Contact resistance is also significantly reduced.

In addition, it is clear that weldability is improved.

〔Effect of the invention〕

By forming a metal or alloy material into a single crystal or a crystal structure arranged in the negative direction, it can be used as a contact material for power plugs and power strips to improve the signal transmission characteristics of audio and video, etc. It is possible to form an excellent signal transmission system in acoustic and electronic equipment such as precision measuring instruments.

In addition, by cold working a single crystal or unidirectionally aligned metal or alloy ingot to create a single crystal or unidirectionally aligned crystal structure, it can be used as a general-purpose contact material with excellent consumability, weldability, and contact resistance. It has significant industrial effects, such as improving the performance of contact materials and making it possible to manufacture highly reliable contact materials.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a heating mold continuous casting apparatus, FIG. 2 is a side sectional view showing an example of a power plug, and FIG. 3 is a side sectional view showing an example of a table tap. 1. Casting furnace 2, mold 3, heating device 4, molten metal 5, ingot 6, pinch roll 7, cooling device 8.9. Contact component 10, insulation case 11, insulators 12, 13. Conductors 14, 15. Contact parts 16, insulation case 17, insulators 18, 19. conductor

Claims (4)

[Claims] (1) A contact material characterized by having a single crystal or unidirectionally aligned crystal structure of a metal or alloy material. (2) The contact material according to claim 1, wherein the metal or alloy is copper or a copper alloy. (3) The contact material according to claim 1, wherein the metal or alloy is a noble metal or an alloy thereof. (4) A method for manufacturing a contact material, which comprises cold working a single crystal of a metal or an alloy or an ingot having a crystal structure aligned in one direction in the crystal direction.