KR20170121307A - COAXIAL CABLE BUNDLE, METHOD FOR PRODUCING Cu-Ag ALLOY WIRE, AND Cu-Ag ALLOY WIRE - Google Patents

Abstract

A Cu-Ag alloy wire having high conductivity and high strength and a method for producing the Cu-Ag alloy wire are provided. A Cu-Ag alloy wire made of a copper alloy containing Ag, which contains 0.1 mass% or more and 15 mass% or less of Ag, and the remainder is made of Cu and impurities. When an arbitrary observation field of view is taken within the range of 1000 nm x 1000 nm in the cross section of the Cu-Ag alloy wire, the area ratio of the precipitates of Ag having a maximum length of 100 nm or less, Is more than 40%. Ag particles dispersed in a very fine granular state are uniformly dispersed and can be dispersed and strengthened, so that the strength can be further improved and a high conductivity can be obtained.

Description

A method of manufacturing a copper-copper alloy bundle, a copper-copper alloy bundle, a method of manufacturing a copper-alloy wire, and a method of manufacturing a copper-

The present invention relates to a Cu-Ag alloy wire, a coaxial cable having a center conductor made of this Cu-Ag alloy wire, a coaxial cable bundle in which a plurality of such coaxial cables are bundled, and a method of manufacturing a Cu-Ag alloy wire. Particularly, the present invention relates to a Cu-Ag alloy wire having a high electrical conductivity and a higher strength.

With the miniaturization and weight reduction of various electric and electronic devices such as electronic devices and medical devices, there has been a demand for further miniaturization of electric wires used in these electric and electronic devices.

It is possible to satisfy the strength and fatigue characteristics (resistance to bending, twisting, etc.) required for the wire even if the wire diameter is small, and it is also possible to satisfy workability (wire drawing, twisted wire, It is required that the conductor material of the electric wire be excellent in breaking strength. Conventionally, a copper wire has been used as a conductor of the electric wire. However, if the copper wire has a low breaking strength and is a fine wire of, for example, 0.1 mm (100 탆) or less, easy.

One of the methods for improving the fracture strength of a conductor material is to add an element and alloy it. For example, Patent Document 1 discloses a Cu-Ag alloy wire containing Ag.

Japanese Patent Application Laid-Open No. 2001-040439

Generally, the copper alloy can increase the strength such as the breaking strength and the like by the increase of the added element, but the conductivity is lowered. Since electric wires used in electronic devices, medical instruments, and the like are required to have a low electric resistance, it is necessary to reduce the electric resistance by increasing the conductor cross-sectional area when a wire material having a low conductivity is used for a conductor. In this case, it is difficult to achieve small curing. Therefore, it is desired to develop a wire having a high electric conductivity and a high strength even when the wire diameter is small.

Therefore, one of the objects of the present invention is to provide a Cu-Ag alloy wire having a high electrical conductivity and a higher strength. Another object of the present invention is to provide a method of manufacturing the Cu-Ag alloy wire. It is still another object of the present invention to provide a coaxial cable having a center conductor made of the Cu-Ag alloy wire, and a coaxial cable bundle in which a plurality of the coaxial cables are bundled.

[Cu-Ag alloy wire]

The present inventors have found that Ag is selected as an additive element which is hard to lower the electric conductivity relatively and which is effective for improving the strength and can be used for a Cu-Ag alloy wire to have a high electric conductivity equal to or higher than that of a conventional Cu- And a Cu-Ag alloy wire having a higher strength was examined in various ways. As a result, it was found that Ag is present in a very fine granular phase, whereby Cu-Ag alloy wire having high conductivity and improved strength can be obtained. The present invention is based on the above findings.

The Cu-Ag alloy wire of the present invention relates to a wire made of a copper alloy containing Ag. The Cu-Ag alloy wire contains 0.1 to 15% by mass of Ag and the remainder is composed of Cu and impurities. In this Cu-Ag alloy wire, when an arbitrary observation field of view is taken within the range of 1000 nm x 1000 nm in the cross-section of the Cu-Ag alloy wire, of the Ag precipitates (crystal precipitates) present in the observation field, Is not less than 40%. ≪ / RTI >

The Cu-Ag alloy wire of the present invention can disperse Ag in a very fine granular state by being uniformly dispersed, so that dispersion can be intensified and the strength can be further improved, and a high electric conductivity can be obtained.

As one form of the Cu-Ag alloy wire of the present invention, the precipitate of Ag further includes a precipitate in the form of a fiber.

Since the precipitate of Ag exists as a precipitate in the form of a fiber, fiber reinforcement can be achieved. The Cu-Ag alloy wire of the above-mentioned type can further improve the strength by precipitation strengthening of Ag by the mixed structure of the fiber strengthening and the dispersion strengthening described above.

The Cu-Ag alloy wire of the present invention can be used as a center conductor of a coaxial cable. A coaxial cable of the present invention relates to a coaxial cable including a center conductor having at least one strand, an insulator covering the periphery of the center conductor, and an outer conductor disposed around the insulator. In this coaxial cable, the stranded wire is the Cu-Ag alloy wire of the present invention.

A plurality of the coaxial cables of the present invention can be bundled to obtain the coaxial cable bundle of the present invention.

The coaxial cable of the present invention or the coaxial cable bundle of the present invention can improve the strength (fatigue characteristic) by precipitation strengthening by using the Cu-Ag alloy wire of the present invention as the center conductor.

[Production method of Cu-Ag alloy wire]

The present inventors have found that Ag is selected as an additive element which is hard to lower the electric conductivity relatively and which is effective for improving the strength and can be used for a Cu-Ag alloy wire to have a high electric conductivity equal to or higher than that of a conventional Cu- And various methods for further improving the strength were examined. As a result, it was found that a Cu-Ag alloy wire having a high conductivity and an improved strength was obtained by devising a manufacturing method as well as setting the content of Ag to a specific range. More specifically, there is a step of forming a state in which Ag is sufficiently solidified in Cu before the drawing process, and a specific heat treatment is applied to the wire material subjected to the drawing process to precipitate Ag, It is possible to obtain a wire having a higher electrical conductivity and an equivalent electrical conductivity as compared with the case where there is no step of solubilizing the wire. The above-described Cu-Ag alloy wire of the present invention can be produced by the method for producing a Cu-Ag alloy wire of the present invention described later.

Here, in a Cu-Ag alloy containing a certain amount of Ag, the conductivity is lowered as the Ag is dissolved in Cu, and the more the Ag is precipitated, the higher the conductivity. Therefore, "to form a state in which Ag is fully solidified in Cu" means that a Cu-Ag alloy containing a certain amount of Ag forms a state in which the conductivity is lower than that in the state where Ag is precipitated and the conductivity is increased .

Further, a state in which a large amount of Ag is precipitated is likely to be formed before the drawing process, typically during casting (particularly when the cooling rate is low).

From the above, it is proposed that Ag be sufficiently dissolved before drawing processing, and that the conductivity is used as an index indicating a state in which Ag is dissolved in Cu.

A method for producing a Cu-Ag alloy wire of the present invention relates to a method for producing a wire material by subjecting a cast material made of a copper alloy containing Ag to a drawing process. In this manufacturing method, when the content of Ag is x (mass%) (0.1 mass%? X? 15 mass%), the conductivity C (% IACS) Satisfies C? (-0.1786) x x + 97. Further, in this manufacturing method, a heat treatment is performed at least once at a heating temperature of 300 ° C or more and a holding time of 0.5 hours or more to the wire material subjected to the drawing process. The calculation method for the conductivity C: C? (-0.1786) x x + 97 will be described later.

In this manufacturing method, a very finely granular Ag is precipitated by forming a material in a state in which Ag is sufficiently solidified, providing the material to a drawing process, and further subjecting the drawn wire to the above- These Ag lips can be uniformly dispersed. The strength of the Cu-Ag alloy wire can be improved by the dispersion strengthening of the fine particles of Ag. In addition to this, Ag precipitated before the drawing process is stretched into a fiber shape by drawing processing, so that the strength can be improved by fiber strengthening. It is considered that a Cu-Ag alloy wire having a high conductivity and high strength can be produced by the above-mentioned ultrafine Ag being uniformly dispersed, with or without fibrous Ag, or by coexistence of both. Examples of the Cu-Ag alloy wire obtained by the above-mentioned production method of the present invention include Ag in an amount of not less than 0.1 mass% and not more than 15 mass%, the remainder being Cu and impurities, .

The Cu-Ag alloy wire of the present invention has high electric conductivity and high strength. The method for producing a Cu-Ag alloy wire of the present invention can produce a Cu-Ag alloy wire having high conductivity and high strength.

Fig. 1 is a graph showing the relationship between the content of Ag and the conductivity in various Cu-Ag alloy materials produced in different manufacturing conditions.
Fig. 2 is a microscopic photograph (500 times) of the wire (φ 2.6 mm) after heat treatment (precipitation heat treatment) on the drawing material, and Fig. 2-3-2 and Fig. 2 (II) show sample No. 2-4-2.
Fig. 3 is a transmission electron micrograph (150000 times) of the wire (φ 0.9 mm) after heat treatment (precipitation heat treatment) on the drawing material, and Fig. 2-3, and Fig. 2-4, and Fig. 2-110.
Fig. 4 is a schematic diagram for explaining the precipitates of Ag present in the micrograph of Fig. 3; Fig.
Fig. 5 is a schematic view for explaining a structure constituting the Cu-Ag alloy wire of the present invention.
6 is a perspective view of the coaxial cable of the present invention.

Hereinafter, the present invention will be described more specifically.

[Cu-Ag alloy wire]

The Cu-Ag alloy constituting the Cu-Ag alloy wire of the present invention is a binary alloy having a content of Ag of 0.1 mass% or more and 15 mass% or less (remaining Cu and impurities). When the content of Ag is 0.1 mass% or more, the effect of improving the strength by precipitation strengthening of Ag tends to be easily obtained. When the content of Ag is 15 mass% or less, the deterioration of the conductivity due to the excessive precipitation of Ag is easily suppressed. Particularly, when the content of Ag is 1% by mass or more and 10% by mass or less, a high strength and a high electric conductivity can be provided with a good balance, which is more preferable. A raw material is prepared so as to have a predetermined composition. The raw material Cu and the raw material Ag have a high purity, for example, those having a purity of 99.9% or more are used, Foreign matter can be reduced.

When the content of Ag is small, fine Ag is easily precipitated in the precipitates of Ag. Here, the size of the fine Ag refers to " the maximum length of the straight line that cuts the ortho-precipitate is 100 nm or less ". On the other hand, the Ag precipitates sometimes contain coarse Ag, and the size thereof refers to " the maximum length of the straight line that cuts the precipitates exceeds 100 nm ". As the content of Ag increases, fibrous Ag precipitates as a precipitate of Ag. This fibrous Ag is a relatively large Ag among the precipitated Ag. Particularly, when the content of Ag is 2 mass% or more, the fibrous Ag is easily confirmed by using a microscope. Most of the precipitates are precipitates, and particulate Ag and fibrous Ag are considered to be substantially precipitates. It is considered that the Ag of the assembly is partially included as the crystallized product.

When the Cu-Ag alloy wire of the present invention has an arbitrary observation field of view within a range of 1000 nm x 1000 nm on the cross section of the Cu-Ag alloy wire, the area ratio of the fine Ag in the positive- More than 40%. In the precipitates of Ag present in the observation field, Ag may be present in addition to fine Ag. Since the fibrous Ag is sufficiently larger than the size of the observation field of view, it is not included in the " precipitate of Ag existing in the observation field of view ". The method of collecting the observation field of view will be described later. By making the structure in which the fine particles of Ag are uniformly dispersed, it is possible to improve the strength by dispersion strengthening. The Ag in the assembly does not adversely affect the characteristics of the Cu-Ag alloy wire, but it is considered that the Ag does not contribute to the improvement of the characteristics.

Further, when the content of Ag is increased, the presence of Ag in the form of fibrous Ag in addition to the fine Ag is able to improve the strength by fiber strengthening. It is considered that the Cu-Ag alloy wire has high conductivity and high strength because the fine Ag is uniformly dispersed, the fibrous Ag is present, or both exist.

The following method is conceivable as a method for contributing to the improvement of the characteristics of the Cu-Ag alloy wire of the Ag of the assembly. Ag, which is particularly large among the Ags in the assembly, is stretched in the form of a fiber at the time of drawing processing, thereby making it possible to improve the strength by fiber strengthening. Ag in the Ag of the assembly is solidified in Cu by heat treatment and precipitated as fine Ag as much as possible so that the strength of the Ag can be improved by strengthening dispersion. As described above, it is considered that the Ag of the assembly can be improved in strength depending on whether Ag of the assembly is made fine or in the form of fiber.

The Cu-Ag alloy wire is typically a circular wire having a circular cross section and may be of various wire diameters. If the wire diameter is not more than 3 mm, particularly not more than 1 mm (1000 mu m), it is preferable to use a wire having a small diameter. Further, since the Cu-Ag alloy wire of the present invention has a high conductivity and a high strength, it is expected that not only twisted wires twisted by twisting microfine wires but also single wires can be sufficiently used for conductors of wires. A fine Cu-Ag alloy wire having a wire diameter of 0.01 mm (10 탆) to 0.08 mm (80 탆) can be obtained by appropriately changing the degree of processing during drawing.

The Cu-Ag alloy wire of the present invention is a very fine Cu-Ag alloy wire having a high wire conductivity and high strength and a wire diameter of not more than 0.05 mm (50 탆), for example, Ag alloy wire having a diameter of? 1 mm to? 3 mm, a conductivity of 95% IACS or more, and a tensile strength of 300 MPa or more. .

In addition, the Cu-Ag alloy wire of the present invention may be provided with a plating layer made of Ag, Ag alloy, Sn, Sn alloy, or the like on its surface. By providing the plating layer, the wettability with the solder and the corrosion resistance can be improved. In the case of producing a Cu-Ag alloy wire having a plated layer, the plating layer may be formed during the drawing process or after the final drawing.

[Coax and Cable Bundles]

6, the coaxial cable 1 according to the present invention includes a center conductor 11, an insulator 12 covering the periphery of the center conductor 11, And an outer conductor (13). The coaxial cable 1 also has an outer covering 14 covering the outer circumference of the outer conductor 13. [ The center conductor 11 has at least one strand and the strand is the Cu-Ag alloy wire of the present invention. The coaxial cable bundle of the present invention can be obtained by bundling a plurality of coaxial cables of the present invention. By using the Cu-Ag alloy wire of the present invention in the central conductor 11 of the coaxial cable 1, the strength (fatigue characteristic) due to precipitation strengthening can be improved.

[Production method of Cu-Ag alloy wire]

The method for producing the Cu-Ag alloy wire of the present invention typically includes the following casting step, drawing step, and heat treatment step.

Casting Process: A process for producing a casting material by using a mixed molten metal in which Ag and Cu of raw materials are dissolved.

Drawing process: A drawing process is performed on the material subjected to the casting process to produce a wire rod of final wire diameter.

Heat treatment step: A step of performing a specific heat treatment to be described later at least once on the drawing material (including the new wire material of the final wire diameter) on which the drawing is performed.

Particularly, as the above-mentioned material to be provided in the drawing process, a solid solution material in which Ag is sufficiently dissolved in Cu is prepared.

[Casting Process]

Continuous casting may suitably be used for the production of the cast material. The continuous casting is a method of continuously producing a long casting material by holding and solidifying the solidifying shell with a pinch roll (packing), for example. The atmosphere of the casting may be an atmospheric atmosphere, but if the atmosphere is made of an inert gas such as Ar, the oxidation of the molten metal can be prevented. One form for forming the solidified material is to set the cooling rate of the molten metal in the casting step to 8.5 DEG C / sec or more. By setting the cooling rate at the time of casting to 8.5 ° C / sec or more, that is, by quenching, Ag precipitation can be suppressed and Ag can be sufficiently solidified. The faster the cooling rate is, the more the deposition of Ag can be suppressed, more preferably 10 ° C / sec or more. On the other hand, as described above, as a mode of pulling the solidification shell, if the speed at which the solidification shell is pulled to increase the cooling rate is increased, there is a fear that the solidification shell can not sufficiently follow. Therefore, it is preferable that the cooling rate be as large as possible in a range in which the cast material is continuously produced.

The cooling rate (° C / sec) at the time of casting is determined by Tm (° C), the temperature immediately before pouring the mixed molten metal into the mold (for example, the temperature in the tundish) (Tm-Tc) / (Tm-Tc) divided by the time t _mc, where _tmc (sec) is the time during which the mixed molten metal moves from the measuring point of the temperature Tm to the measuring point of the temperature Tc, t _mc .

In order to set the cooling rate at the time of casting to 8.5 DEG C / sec or more, for example, a water-cooled copper mold is used for the mold, or a forced cooling process is performed so as to surround the periphery of the coagulated shell to be drawn, Or disposing means. The forced cooling means may be, for example, a water-cooled copper block or a fan-blowing means. By these means, the atmosphere around the solidifying shell can be cooled, and the solidified shell is cooled by the cooled atmosphere. The cooling rate can be adjusted by appropriately adjusting the temperature of the forced cooling means and the drawing speed (casting speed) of the solidifying shell.

[Solution treatment]

Alternatively, as one form for forming the solidified material, the casting material obtained by the casting step (which may be quenched or quenched as described above) may be subjected to solution treatment . In this solution treatment, the heating temperature is preferably 600 ° C or more, the holding time is 0.5 hours or more, and the cooling rate is 1.5 ° C / sec or more.

By setting the heating temperature to 600 DEG C or more and the holding time to 0.5 hour or more, Ag can be sufficiently dissolved in Cu even if Ag is precipitated in the cast material. As the heating temperature is higher, Ag tends to be sufficiently contained in Cu. However, when the heating temperature is too high, the Cu-Ag alloy begins to dissolve, so that the heating temperature is preferably 850 ° C or lower. The longer the holding time, the more tendency is to be able to sufficiently solidify the Ag in Cu, so that it is preferable that the upper limit is not particularly set but it is appropriately selected so as not to cause a decrease in productivity.

When the cooling rate at the time of solution treatment is set to 1.5 ° C / sec or more, that is, quenching is carried out, deposition of dissolved Ag can be suppressed, and Ag can be sufficiently solved. The higher the cooling rate during the solution treatment, the more the deposition of Ag can be suppressed, more preferably 3 deg. C / sec or more, and the upper limit is not particularly set.

The cooling rate (占 폚 / sec) during the solution treatment is obtained by measuring the temperature of the sample 1 minute after the commencement of the cooling by T ₁ (° C) and the solution treatment temperature Tr (° C) , The temperature difference: (Tr-T ₁ ) is divided by the time: 60 seconds.

In order to set the cooling rate at the solution treatment to 1.5 DEG C / sec or more, a forced cooling means can be suitably used. For example, direct cooling using a fluid having a fluidity such as water, oil, sand or the like, windwash using a fan or the like, or a water-cooled copper block can be used. The cooling by the water-cooled copper block can be performed, for example, by disposing a water-cooled copper block so as to surround the periphery of the wire drawn out from the heat treatment furnace and cooling the atmosphere around the wire. The cooling rate can be adjusted by appropriately adjusting the refrigerant temperature, the arrangement state of the forced cooling means, the amount of refrigerant, the air flow rate, and the like.

[Fresh Process]

The drawing process (typically, cold) is performed over a plurality of passes until it becomes the final diameter. The degree of processing of each pass may be appropriately adjusted in consideration of the composition (content of Ag), final wire diameter, and the like.

[Heat treatment]

Specifically, the drawing material subjected to the drawing process, specifically, the drawing material drawn in the middle of the drawing process, or the drawing material drawn to the final drawing diameter is subjected to heat treatment under specific conditions to deposit Ag from the state in which Ag is sufficiently solid. By this heat treatment, it is considered that the fine grain of nano-grain Ag precipitates. By the presence of the finely dispersed Ag particles uniformly dispersed therein, it is possible to obtain Cu-Ag having a higher strength than that of a wire having the same deposition amount of Ag, It is considered that an alloy wire can be produced.

The heat treatment (hereinafter referred to as precipitation heat treatment) may be performed at least once in the drawing-processed wire, or may be performed a plurality of times. When the precipitation heat treatment is performed once, the productivity is low and the productivity is low. When the precipitation heat treatment is performed a plurality of times, the precipitation of Ag, particularly the precipitation of fine Ag, is increased to increase the strength and conductivity, It is possible to improve the conductivity by removing the processing strain or to facilitate the subsequent drawing process.

The precipitation heat treatment conditions are a heating temperature of 300 ° C or higher and a holding time of 0.5 hour or higher. When the heating temperature is less than 300 占 폚 and the holding time is less than 0.5 hour, Ag can not be sufficiently precipitated or the processing strain can not be sufficiently removed. The higher the heating temperature and the longer the holding time, the more easily Ag is precipitated. However, when the temperature is higher than 600 DEG C, the Ag is again dissolved in Cu, thereby lowering the conductivity. Therefore, the heating temperature is preferably 600 ° C or lower, particularly 350 ° C or higher and 550 ° C or lower, more preferably 400 ° C or higher and 450 ° C or lower, and the holding time is preferably 0.5 hour or more and 10 hours or less. The cooling during the precipitation heat treatment may be, for example, furnace cooling which is left in a heat treatment furnace and cooled by natural cooling.

(Test Example 1)

Cu-Ag alloy material was prepared under various conditions, and the relationship between the content of Ag and the conductivity was investigated. The results are shown in Fig. 1 and Table 1.

The Cu-Ag alloy material was produced as follows. (Ag) having a purity of 99.99% or more as a raw material Cu and silver (Ag) having a purity of 99.99% or more as a raw material Ag were prepared as a raw material Cu, charged into a crucible made of high purity carbon and vacuum- melted in a continuous casting apparatus to dissolve Cu and Ag To prepare a mixed molten metal. As shown in Fig. 1 and Table 1, the amount of silver added was adjusted so that the Ag content (concentration) with respect to the mixed molten metal was 1% by mass to 15% by mass.

Using the obtained mixed molten metal and the high-purity carbon mold, continuous casting was carried out to produce a cast material having a circular cross section having a diameter of 8.0 mm. 1 (casting (slow cooling)) shown in Fig. 1 is a sample in which the cooling rate during casting by natural cooling is 1.5 占 폚 / sec (less than 8.5 占 폚 / sec) ) Is a sample in which forced cooling means such as water-cooled copper is disposed so as to surround the periphery of the solidified shell taken out from the mold, and the cooling rate is set to 10 ° C / sec (8.5 ° C / sec or more) (Solution treatment treatment material) was subjected to a solution treatment (heat treatment treatment) of 760 占 폚 for 2 hours and a cooling rate of 9 占 폚 / sec (1.5 占 폚 / sec or more) to the cast material (cooling rate at casting: 2.5 占 폚 / Respectively.

As shown in Table 1 and Fig. 1, even if the content of Ag is the same, the conductivity is different according to the production conditions. Specifically, when the Ag content is the same, (1) the conductivity is lower than when the cooling rate at the time of casting is slower than when the casting speed is slower, (2) It can be seen that the conductivity is lowered. The reason why the conductivity is lowered in this way is considered to be that the Ag is in a state of being solid-dissolved in Cu by accelerating the cooling rate at the time of casting or by performing solution treatment after casting. For this reason, it can be said that the conductivity when the cooling rate at the time of casting is slow can be used as a threshold value as the index indicating the "state in which Ag is solved in Cu" as a threshold value.

Therefore, a formula approximating the relationship between the content of Ag and the conductivity when the cooling rate is slow is considered. From the data shown in Fig. 1, the conductivity when the cooling rate at the time of casting is slow is grasped as a linear function with the content of Ag as a variable. Therefore, when the approximate line of the conductivity when the cooling rate at the time of casting is slow is obtained by using commercially available table calculation software "Excel" by Microsoft Corporation, the content of Ag is x (mass%) and the conductivity is C , C = (- 0.1786) x x + 97 is obtained. When this approximate expression is used, the above-mentioned " state in which Ag is solved in Cu " refers to a state in which the conductivity is equal to or lower than the conductivity when the cooling rate at the time of casting is slow, (-0.1786) x x + 97.

(Test Example 2)

A Cu-Ag alloy wire was manufactured by subjecting the material made of a Cu-Ag alloy under various conditions to a drawing process and a suitably heat treatment to investigate a conductivity (% IACS) and a tensile strength (MPa).

Each sample was produced as follows. A raw material similar to that of Test Example 1 was prepared, and a mixed metal of Cu and Ag was prepared so that the content (concentration) of Ag was as shown in Table 2. Then, as in Test Example 1, A circular cast material was produced. The cooling conditions at the time of casting were changed so that the cooling rates shown in Table 2 were obtained for each cast material. A sample having a cooling rate of less than 8.5 ° C / sec is a sample obtained by natural cooling. In the sample having a cooling rate of 8.5 ° C / sec or more, a water-cooled copper block is disposed so as to surround the periphery of the solidified shell taken out from the mold, the ambient atmosphere is cooled, a fan is placed, , And these samples are quenched by combining these forced cooling means. The cooling rate at the time of casting is made different by appropriately adjusting the temperature and air volume of the water-cooled copper block.

The samples (No. 2-1, 2-3, 2-3-2, 2-5, 2-7, 2-10, 2-12, 2-14) in which only the cast material was described in the manufacturing conditions of Table 2, The obtained cast material was subjected to a drawing process, subjected to an intermediate heat treatment (precipitation heat treatment) under the conditions shown in Table 2 at the time of cornering shown in Table 2, and further subjected to a drawing process to obtain a final diameter:? 0.04 mm (Cu-Ag alloy wire).

The samples (No. 2-2, 2-4, 2-4-2, 2-6, 2-8, 2-9, 2-11, 2-13 , 2-15) were subjected to a heat treatment (solution treatment) under the heat treatment conditions shown in Table 2 and subjected to drafting treatment to the obtained cast materials, and subjected to intermediate heat treatment under the conditions shown in Table 2 (Cu-Ag alloy wire) having a final wire diameter of? 0.04 mm obtained by performing drawing processing (precipitation heat treatment) and further drawing processing. In the heat treatment (solution treatment) condition of Table 2, "quenching" means cooling by water cooling in the cooling step from the heating temperature.

Sample No. 2-100 was subjected to heat treatment (solution treatment) under the conditions shown in Table 2 to the obtained cast material (diameter 8.0 mm), and then subjected to drafting treatment. (Cu-Ag alloy wire) having a final wire diameter of? 0.04 mm obtained by carrying out an intermediate heat treatment under the above-mentioned conditions and further drawing. Sample No. 2-110 was obtained by subjecting the obtained cast material (diameter: φ 8.0 mm) to a drawing process and then subjected to an intermediate heat treatment under the conditions shown in Table 2 at the time of line drawing shown in Table 2, (Cu-Ag alloy wire) having a final diameter of 0.04 mm. Sample No. 2-120, the obtained cast material (diameter: 8.0 mm) was subjected to the drawing process to a diameter of 6.6 mm without performing the solution treatment, and the obtained drawing material (diameter: 6.6 mm) (Solutioning treatment) was carried out under the conditions shown in Table 2, and then additional drawing was carried out. After the intermediate heat treatment was carried out under the conditions shown in Table 2 at the time of wire drawing shown in Table 2, Wire diameter: φ 0.04mm wire (Cu-Ag alloy wire).

The conductivity (% IACS) was measured for each solution treatment material (diameter φ 8.0 mm) subjected to solution treatment to the obtained cast material (diameter φ 8.0 mm) and cast material (wire diameter φ 8.0 mm). The results are shown in Table 2. The tensile strength (MPa) and the electric conductivity (% IACS) of the Cu-Ag alloy wire subjected to the intermediate heat treatment (precipitation heat treatment) under the above-mentioned heat treatment and subjected to the respective diameters of φ 2.6 mm or φ 0.9 mm were measured. The results are shown in Table 2. The tensile strength (MPa) and the electric conductivity (% IACS) were also measured for a wire rod having a final wire diameter of? 0.04 mm. The results are shown in Table 2. The tensile strength was measured in accordance with JIS Z 2241 (1998) (gauge length GL: 10 mm). The conductivity was measured by the bridge method.

As shown in Table 2, it can be seen that the higher the Ag content, the higher the strength is. Particularly, when the cooling rate at casting is set to 8.5 ° C / sec or more, or the casting material is subjected to a solution treatment under specific conditions, and the electric conductivity C (% IACS) satisfies C? (-0.1786) x x + 97 And the sample was subjected to a specific heat treatment (precipitation heat treatment). 2-1 to 2-15 can be found to have a high strength immediately after the heat treatment, while having a conductivity equal to or higher than that of the cast material (slow cooling rate, see casting (slow cooling) in Table 1). Then, It can be seen that 2-1 to 2-15 are high strength even in the final wire diameter.

Further, samples having the same Ag content are compared. A sample No. 1 having a slow cooling rate at the time of casting, a low heating temperature during solution treatment, and a slow cooling rate. 2-100, the cooling rate at the time of casting was slow, and the sample No. 2 in which the solution treatment was not performed. 2-110 is a sample No. 2 produced by the above-mentioned specific conditions. 2-3, 2-4, 2-3-2 and 2-4-2, it was found that even when the conductivity after the solution treatment was high, it was found that any of the strengths immediately after the heat treatment during the drawing and the final wire diameter was low . Further, the sample No. before the fresh material is not used as the specific employment material. 2-120 is a sample No. 1. 2-4, 2-3-2 and 2-4-2, respectively.

The obtained sample no. 2-3-2 and 2-4-2, the cross section was observed with a microscope (500 times), and the observed image was processed by image processing, as shown in Fig. In Fig. 2, in the case of the elongated nodule, precipitated Ag is increased. The size of the fibrous Ag is in the order of microns, and it can be seen that the length is about several tens of microns.

Next, the precipitates of Ag are observed. If the fibrous Ag in the microphotograph can be confirmed, a sample for observing the Ag precipitates is collected at the portion where the fibrous Ag is not present. The observation sample is preferably observed at the longitudinal section (cut surface along the drawing direction of the Cu-Ag alloy wire) in order to exclude the fibrous Ag. An arbitrary observation field is taken within the range of 1000 nm x 1000 nm from the observation sample and observed with a transmission electron microscope, whereby the precipitates of Ag can be confirmed.

Fig. 2-3, 2-4, and 2-110, transmission electron micrographs (150000 times) of cross sections are shown. The observation field of view is a region of 440 nm x 326 nm. The total area of these fine grains was calculated by counting the number of precipitates having a maximum straight line length of not more than 100 nm (fine grains) of straight lines cutting the precipitates among the precipitates of Ag present in the observation field. The Ag precipitates consisted of particles including all of them in the observation field of view, and the particles partially located on the outline of the observation field of view were outside the object to be measured. Fig. 4 shows a schematic diagram for explaining the silver halide as fine grains among the precipitates of Ag present in the micrograph of Fig. Ag surrounded by circles indicated by dotted lines in Fig. 4 is fine. Table 3 shows the total area of the precipitates, the total area of the fine particles, the area ratio of the positive precipitates in the observation field, and the area ratio of the fine particles in the positive precipitates. In addition, 2-1 and 2-2 are also shown in Table 3.

Sample No. subjected to a specific heat treatment. In 2-3, there were nine fine grains in the observation field, and the area ratio of the fine grains in the precipitates was 68.9%. The sample No. 1 subjected to the solution treatment in the cast material. In 2-4, all of the precipitates present in the observation field were fine, and the number of the fine grains was 23, and the number of fine grains in the sample No. 2 was 24. 2-3. On the other hand, although the content of Ag was the same, the cooling rate at the time of casting was slow, and the sample No. 2 in which the solution treatment was not carried out. 2-110 is a sample No. 2-110. 2-3 and 2-4, the number of fine grains existing in the observation field was as small as four, and the area ratio of fine grains in the precipitate was 26.1%. The sample Nos. 2-3 and 2-4, respectively. 2-1 and 2-2. 2-3 and 2-4 were obtained.

Fig. 5 is a schematic diagram illustrating a structure constituting the Cu-Ag alloy wire of the present invention. In the figure, the elliptical body and the black circle in the rectangular frame represent the precipitated Ag, and the white circle represents the dissolved Ag. As one of the causes of the electric conductivity and tensile strength shown in Table 2, as shown in Fig. 2, there is a fiber reinforcing method in which Ag is stretched and is present in the form of fiber, and as shown in Fig. 3, It is conceivable that they are due to dispersion strengthening by the existence of particles uniformly dispersed or by having a mixed structure by both. As shown in Fig. 5, for example, the mixed structure is formed by applying a solution treatment to the cast material to solidify the precipitated Ag, thereby increasing the solid content of Ag, As a result, the Ag precipitated without being solubilized in the solution treatment is stretched by drawing to form a fibrous phase, and by the above-described precipitation heat treatment, the Ag that has been solidified becomes a fine granular phase and precipitated in a large amount, . In contrast, for example, when a cooling rate at the time of casting is low, a relatively large amount of Ag precipitates, and the Ag is stretched by the drawing process as described above. However, even if the precipitation heat treatment described above is carried out, And only Ag, which is mainly fibrous, is present. It is considered that due to the difference in the presence state of Ag, there is a difference in strength as described above.

In addition, from the test results, it can be said that the strength of the sample subjected to the solution treatment under a specific condition of the cast material tends to be higher than that of the sample whose cooling rate at the casting is 8.5 ° C / sec or more . It can be said that the above-mentioned specific heat treatment (precipitation heat treatment) carried out in the course of drawing tends to further increase the strength at the final line diameter when the line diameter is larger. Further, even when the conductivity is the same after the above specific heat treatment (precipitation heat treatment), it can be said that the higher the cooling rate at the time of forming the solidified material, the higher the strength after the heat treatment and the final diameter.

From the above test results, it was found that, in preparation of a Cu-Ag alloy wire containing a specific amount of Ag, a solidified material in which Ag is sufficiently solid is prepared as a material to be provided for drawing, It is possible to obtain a wire rod having a higher conductivity than that of a conventional Cu-Ag alloy wire containing the same amount of Ag and having the same or higher conductivity.

On the other hand, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, the content of Ag, the cooling rate during casting, the conditions of the solution treatment (temperature, holding time, cooling rate), the conditions of the wire diameter and precipitation heat treatment to perform solution treatment or precipitation heat treatment Can be appropriately changed.

The Cu-Ag alloy wire of the present invention can be used as a wire for a variety of electric and electronic devices such as a portable electronic device called a mobile phone, an electronic component mounted on an automobile, a medical device, an industrial robot, Shielded conductors). The method for producing the Cu-Ag alloy wire of the present invention can be suitably used for producing the Cu-Ag alloy wire of the present invention having high conductivity and high strength. The coaxial cable of the present invention and the coaxial cable bundle of the present invention can be suitably used for the power supply wiring of the various electric / electronic devices.

1: Coaxial cable
11: center conductor
12: Insulator
13: External conductor
14: Exterior

Claims (6)

A coaxial cable bundle comprising a plurality of coaxial cables having a central conductor having at least one strand, an insulator covering the periphery of the central conductor, and an outer conductor disposed around the insulator,
Wherein the Cu-Ag alloy wire composed of a copper alloy containing Ag as a main component contains 0.1 mass% or more and 15 mass% or less of Ag and the remainder is composed of Cu and impurities, The area ratio of the positive precipitate having a maximum length of a straight line cutting the positive precipitate of 100 nm or less among the precipitates of Ag existing in the observation field is 40% or more when an arbitrary observation field is taken within 1000 nm, Bundles. The method according to claim 1,
The coaxial cable bundle further comprising a precipitate of fibrous form in the precipitate of Ag. A method of producing a Cu-Ag alloy wire for producing a wire by subjecting a cast material made of a copper alloy containing Ag to a drawing process,
(% IACS) of the material is C? (- mass%) when the content of Ag is x (mass%) (0.1 mass%? X? 15 mass%), 0.1786) x x + 97, and a heat treatment in which the heating temperature is 300 ° C or more and the holding time is 0.5 hours or more is performed at least once on the wire material subjected to the drawing process. -Ag alloy wire. The method of claim 3,
The solution material is formed by applying a solution treatment to the cast material and the solution treatment is carried out at a heating temperature of 600 ° C or higher, a holding time of 0.5 hours or more, and a cooling rate of 1.5 ° C / sec or more Wherein the Cu-Ag alloy wire is produced by a method comprising the steps of: The method of claim 3,
Wherein the cast material is formed by setting the cooling rate of the molten metal in the casting step to 8.5 DEG C / sec or more. A method for producing a Cu-Ag alloy wire according to any one of claims 3 to 5, which comprises the steps of: adding 0.1 mass% or more and 15 mass% or less of Ag and the remainder being Cu and impurities; Mu m or less.

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