JP3942123B2 - High durability movable electric wire, high durability movable cable and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technology of electric wires and cables, and particularly relates to a movable electric wire and a movable cable excellent in conductivity and durability. Such a movable electric wire and a movable cable are suitably used for supplying an electric current for power or transmitting an electric signal for control through a movable part (arm) in an industrial robot, for example.
[0002]
[Prior art and problems to be solved by the invention]
In an industrial robot, the arm moves in a complicated manner, so that a power supply cable or a signal transmission cable to a welding device or the like attached to the tip of the arm frequently undergoes a bending action at the arm joint portion. For this reason, in particular, a movable cable and a movable cable such as a robot cable and an electric wire used therefor are required to have high durability against bending in order to extend their life.
[0003]
On the other hand, in these movable electric wires and movable cables, as the mechanical operation speed of the movable portion to which they are attached is further improved, the conductive wires are required to be thinned to reduce the weight. Of course, there should be no reduction in bending durability even in this thinning.
[0004]
Conventionally, in industrial robots, tough pitch annealed copper wire has been mainly used as the electric wire constituting the movable cable as described above. The twisted tough pitch annealed copper wire is covered with an insulator to form a covered electric wire, and a plurality of these covered electric wires are further externally covered with a sheath to obtain a movable cable for a robot. And when durability is especially requested | required, the electric wire using what is called a highly durable copper alloy, such as a tin containing copper alloy, is used. This highly durable copper alloy wire has a durability about five times that of a tough pitch annealed copper wire.
[0005]
However, since conductivity and tensile strength are generally contradictory properties, increasing the content of the metal added to the copper alloy increases tensile strength but decreases conductivity. For example, pure copper has a conductivity of 100% IACS (International Annealed Copper Standard) and exhibits high conductivity, but has a tensile strength of 40 kg / mm. ² It is as follows. In contrast, typical beryllium copper for springs has a tensile strength of 100 kg / mm. ² As described above, the conductivity is 30% IACS or less.
[0006]
The tin-containing copper alloy wire described above is already used for a trolley wire or the like, but as the amount of tin added increases, the mechanical strength increases, but the conductivity decreases. For example, in the case of a 0.3% tin-containing copper alloy, the conductivity is 70% IACS, but in the case of a 0.6% tin-containing copper alloy having an increased strength, the conductivity is 50-60% IACS. Naturally, when the conductivity is low, the conductive wire diameter must be increased in order to suppress the generation of Joule heat. However, this is contrary to the demand for improving the mobility of the robot arm by reducing the weight based on thinning.
[0007]
Recently, as a material that has been proposed with the aim of satisfying both higher conductivity and higher bending durability, there is a so-called in-situ formed metal fiber reinforced copper matrix composite material.
[0008]
As an example, an ingot obtained by melting and casting alloy components such as copper and niobium that are hardly in solid solution with each other is hot or cold processed to form niobium fibers in situ to form a copper matrix. It is possible to make a reinforced wire or plate. Regarding this, for example, J. Org. Bevk et al. , J .; Appl. Phys. vol. 49 (1978) 6031.
[0009]
According to this, for example, in the case of copper-niobium, dendritic crystals of niobium are precipitated during casting, and this is stretched into fibers in situ by processing, which reinforces the copper matrix. However, niobium has a high melting point and requires melting by an arc furnace or electron beam melting, and there is a problem in productivity for industrial use.
[0010]
Recently, studies have been made on in-situ formed silver fiber reinforced copper matrix composites and in-situ formed chrome fiber reinforced copper matrix composites that do not use refractory metals such as niobium. For example, Y. Sakai et al. , Appl. Phys. Lett. , Vol. 59 (1991) 2965; Takeuchi et al. , J .; Less-Common Metals, vol. 157 (1990) 25.
[0011]
From the viewpoint of industrial implementation, it is preferable to use low-cost chromium compared to silver. However, in-situ formed chromium fiber reinforced copper matrix composite material has a desired mechanical strength (bending durability) because chromium is brittle. However, it is not easy to make the chrome fiber diameter sufficiently small on an industrial scale by the conventionally proposed method. It has not been possible to achieve good mechanical strength in movable electric wires produced on a scale.
[0012]
In order to solve such problems caused by the brittleness of chromium, in the technique described in JP-A-9-235633, a ductile alpha iron phase other than chromium is interposed in a copper matrix, and the iron phase is processed. By transmitting the generated stress to the brittle chromium phase, the copper matrix is fibre-reinforced by stretching the chromium into finer fibers. In this method, fine chromium fibers can be formed in situ, but since an iron phase is interposed, when this extremely fine iron is dissolved in the copper matrix, the iron is compared with other elements. Since the electrical conductivity is extremely lowered, it is necessary to avoid solid solution of iron in copper, and it is extremely difficult to control the components for that purpose, which raises the manufacturing cost.
[0013]
Therefore, the present invention solves the above-mentioned problems of the in-situ formed chromium fiber reinforced copper matrix composite material due to the brittleness of chromium, and industrially provides a conductive material with improved both conductivity and bending durability. An object of the present invention is to provide a movable electric wire using a conductive wire having high conductivity and high bending durability using this material.
[0014]
Furthermore, an object of the present invention is to provide a movable cable that has high durability against repeated bending by using a movable electric wire as described above, can be reduced in weight, has excellent mobility, and can have a long life. Is.
[0015]
[Means for Solving the Problems]
According to the present invention, the object as described above is achieved.
Using a wire composed of an in-situ formed chromium fiber reinforced copper matrix composite material including a copper matrix and an in-situ formed fibrous chromium having an average diameter of 2.5 μm or less and an average diameter of 1.0 μm or less in the copper matrix A highly durable movable electric wire, characterized in that a conductive wire is formed,
Is provided.
[0016]
In one aspect of the invention, the in-situ formed chromium fiber reinforced copper matrix composite is 1-25% by weight chromium, with the balance being substantially copper.
[0017]
In addition, according to the present invention, the object as described above is achieved.
Conductive wires are formed using a wire composed of a copper matrix, an in situ formed fibrous chromium in the copper matrix, and an in situ formed chromium fiber reinforced copper matrix composite material containing silver or zirconium dispersed in the copper matrix. A highly durable movable electric wire, characterized by being formed,
Is provided.
[0018]
In one embodiment of the present invention, the in-situ formed chromium fiber reinforced copper matrix composite material has a chromium content of 1 to 25% by weight and a silver or zirconium content of 0.01 to 8% by weight with the balance being substantially copper. is there.
[0019]
In one aspect of the present invention, the in-situ formed chromium fiber reinforced copper matrix composite material has a conductivity of 65% IACS or more and a tensile strength of 850 MPa or more.
[0020]
In one aspect of the present invention, the wire has a wire diameter of 300 μm or less.
[0021]
In one aspect of the present invention, the conductive wire is a bundle of a plurality of the wires.
[0022]
In one aspect of the present invention, the plurality of wires are twisted together.
[0023]
In one aspect of the present invention, an insulating coating layer is attached to the conductive wire.
[0024]
In addition, according to the present invention, the object as described above is achieved.
A highly durable movable cable comprising: a linear body including at least one of the above highly durable movable electric wires; and a sheath surrounding the linear body;
Is provided.
[0025]
Furthermore, according to the present invention, the object as described above is achieved.
An alloy material consisting essentially of copper with a chromium content of 1 to 25% by weight is swaged as necessary, then subjected to a first cold wire drawing, then solution treatment, and then second. A high-durability characterized by forming a wire chrome in-situ in a copper matrix to form a wire, and forming a conductive wire using at least one of the wires Manufacturing method of movable wire,
Is provided.
[0026]
In addition, according to the present invention, the object as described above is achieved.
An alloy material consisting of a chromium content of 1 to 25% by weight and a silver or zirconium content of 0.01 to 8% by weight and the balance substantially consisting of copper is optionally swaged and then first cold drawn. Processing, followed by solution treatment, followed by a second cold wire drawing, followed by age hardening, thereby forming fibrous chromium in situ in the copper matrix and silver or silver in the copper matrix. A method for producing a highly durable movable electric wire, characterized in that a wire is obtained by dispersing and precipitating zirconium, and a conductive wire is formed using at least one of the wires.
Is provided.
[0027]
In one aspect of the present invention, the cross-sectional area before processing in processing from the alloy material to the wire is A. ₀ And the cross-sectional area after processing is A, and the processing degree η is ln (A ₀ / A), the first wire drawing is performed until the degree of work η from the alloy material becomes 3-4.
[0028]
In one aspect of the present invention, the cross-sectional area before processing in processing from the alloy material to the wire is A. ₀ And the cross-sectional area after processing is A, and the processing degree η is ln (A ₀ / A), the second wire drawing is performed until the degree of work η from the alloy material becomes 7 or more.
[0029]
In one aspect of the present invention, each of the first wire drawing and the second wire drawing is performed by repeating a drawing process at which the degree of processing η per process is 0.01 to 0.5, a plurality of times. Run with.
[0030]
In one embodiment of the present invention, the solution treatment is performed by heating to 780 to 1000 ° C.
[0031]
In one aspect of the present invention, the age hardening treatment is performed by heating at 200 to 450 ° C. for 30 to 90 minutes.
[0032]
In addition, according to the present invention, the object as described above is achieved.
Forming a linear body using at least one highly durable movable electric wire manufactured by the above manufacturing method, and surrounding the linear body with a sheath;
Is provided.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0034]
In the present invention, in order to obtain a highly conductive and highly durable in-situ formed chromium fiber reinforced copper-based composite material, the fiber diameter of the in-situ formed chromium fiber is reduced until a desired strength is obtained (thinning), The desired high bending resistance is provided by composite reinforcement with the thinned chromium fiber. And for that purpose, in the middle of wire drawing (for example, drawing using a die), a heat treatment that is contrary to common sense is applied as a treatment for increasing the strength of solution treatment. Although the hardness of the material once decreases by this solution treatment, the hardness can be restored by the subsequent cold wire drawing and further thinning can be achieved.
[0035]
FIG. 1 shows a change in the hardness of a composite material accompanying a change in processing degree (progress of processing) when manufacturing a movable electric wire according to the first embodiment of the present invention. The degree of processing is indicated by η, which indicates the cross-sectional area before processing of the composite material in the diameter reduction process such as wire drawing. ₀ And the cross-sectional area after processing is A, and ln (A ₀ / A).
[0036]
The component composition of the alloy material (composite material) used at the start of processing contains 1 to 25% by weight of chromium, and the balance is substantially made of copper. If the chromium content exceeds 25% by weight, the conductivity of the copper-based alloy material tends to decrease, and the desired conductivity tends not to be obtained. If the chromium content is less than 1% by weight, chromium is the second phase. It becomes difficult to exist, and it tends to be difficult to form the chromium fiber in situ.
[0037]
As shown in FIG. 1, the cast ingot of the alloy material as described above is first roughly machined by swaging until the degree of work η becomes m (for example, 2). The increase in the hardness Hv at this time is only a contribution due to work hardening.
[0038]
Next, cold wire drawing (first wire drawing) is performed. This first wire drawing process is preferably performed by repeating the drawing process using a hole die so that the processing degree Δη per time becomes 0.01 to 0.5. This is because the deformability of chrome must be able to follow the deformation of copper because the deformability of copper and the deformability of chromium are remarkably different. If this range is exceeded, only copper will be deformed and chromium will tend to break. Conversely, if it falls below this range, the working efficiency will tend to be extremely reduced.
[0039]
In FIG. 1, the shaded portion indicates the contribution due to fiber reinforced hardening. In FIG. 1, in the region up to point a, the increase in hardness mainly contributes to the reinforcement of the copper matrix by processing, and the contribution of chromium fiber reinforcement is relatively small. In the region between points a and b, the contribution of chromium fiber reinforcement by processing increases, and the contribution of work hardening slows down.
[0040]
When the degree of work η reaches n, solution treatment is performed. This solution treatment is performed, for example, by performing heat treatment at a temperature of 780 to 1000 ° C., for example, 900 ° C. for 30 minutes (the heating time may be sufficient to obtain a uniform temperature distribution). As a result, the copper matrix and the chromium phase enter the annealed state or the recrystallized state from the work-hardened state, and the hardness decreases from the b point to the b ′ point. In the state of this b 'point, only the contribution of fiber reinforced hardening remains. When the degree of work immediately before the start of solution treatment (work degree from the start of swaging) η exceeds 4, voids tend to start to form inside the material, and the degree of work immediately before the start of solution treatment When η exceeds 5, the voids inside the material become large, cracks are generated, breakage tends to occur and processing tends to be impossible. Accordingly, the solution treatment is preferably performed before such a state is reached. For example, the first wire drawing is preferably performed until the degree of work η is 3 to 4 (that is, n = 3 to 4). .
[0041]
Next, in the same manner as before the solution treatment, however, cold wire drawing (second wire drawing) is performed until the working degree η becomes p. This second wire drawing process is also preferably performed by repeating the drawing process using a hole die so that the processing degree Δη per time becomes 0.01 to 0.5. In the region from the point b ′ to the point c, the contribution due to work hardening increases due to reentry into the processed state, and at the same time, the contribution due to fiber reinforced hardening also occurs. The region from the point c to the point d mainly indicates the contribution of hardening due to the refinement of the chrome fibers due to the progress of processing. It can be seen that the hardness is further increased at the point d where the processing degree η becomes p than at the point b. The degree of processing η at the point p is 7 or more (that is, p> 7). In this second wire drawing, it is possible to process to a processing degree of about 8-9 (the diameter of the obtained wire can be 300 μm or less, for example, 50-100 μm), and the processing degree at the p point is The higher the value, the smaller the chrome fiber diameter, and the greater the strength improvement effect.
[0042]
In FIG. 2, the graph of the change of the chromium fiber diameter accompanying progress of a process is shown. This measurement was performed as follows. That is, a sample processed to a predetermined degree of processing is etched to remove copper, and only the chrome fibers are taken out and photographed by SEM. This photograph was converted into an image by digital processing, and the fiber diameter distribution was determined using an image analysis method.
[0043]
As shown in FIG. 2, when the processing degree η is 3, that is, when the processing degree after processing obtained by adding swage processing and cold drawing is 3, the diameter of the chromium fiber formed in situ in the copper matrix is about It varies greatly from 8.5 to 0.5 μm, and the average diameter is about 2.2 μm. This indicates that the ultra-small diameter chrome dendrite formed when the Cu-Cr alloy was cast was somewhat stretched into a fiber shape. Overall, the processing was insufficient and the fiberization itself was sufficient. Indicates that it has not been achieved.
[0044]
When the processing degree η after processing, which includes swage processing and cold wire drawing, is 4, the maximum diameter is somewhat smaller and the average diameter is also reduced accordingly, but the average diameter is still about 2 μm, which is still sufficient. I can't say that.
[0045]
When solution treatment is performed at this point, the maximum diameter is about 11 μm and the average diameter is about 2.8 μm.
[0046]
Subsequently, when the cold wire drawing is continued, the maximum diameter and the average diameter sequentially decrease as the workability η increases. When the workability η exceeds 7, the maximum diameter is 2.5 μm or less and the average diameter is 1 It becomes 0.0 μm or less (so-called submicron region), and required characteristics can be obtained. In general, the overall strength of an in-situ metal fiber reinforced composite material can be described by a term based on a so-called composite rule and a term in which the particle diameter in the Hall-Petch equation is replaced with the fiber diameter. In the latter term, the strength increases as the fiber diameter decreases, and the strength increases in proportion to the inverse of the square of the fiber diameter. When the average diameter of the chrome fibers is 1.0 μm or less, that is, in the submicron region, sufficient strength can be obtained. Specifically, when the maximum diameter of the chromium fibers formed in situ in the copper matrix is 2.5 μm or less and the average diameter is a submicron size, a tensile strength of 850 MPa or more and a conductivity of 65% IACS or more are achieved. When the maximum diameter of the chrome fiber exceeds 2.5 μm or the average diameter exceeds 1 μm, it is difficult to obtain the desired characteristics excellent in both strength and conductivity intended in the present invention. .
[0047]
The processing degree η at the end of the second wire drawing is 7 or more. In the present invention in which the solution treatment is performed in the middle of the wire drawing, it is possible to realize a processing degree of 7 or more, which is difficult to exceed the processing degree of 5 when the solution treatment is not performed. It was. As a result, the chrome fibers are sufficiently thin to effectively strengthen the chrome fibers, and industrial application of the movable wire of the present invention is achieved.
[0048]
FIG. 3 shows a change in hardness of the composite material accompanying a change in processing degree (progress of processing) when a movable electric wire according to the second embodiment of the present invention is manufactured. In this figure, the same terms as in FIG. 1 are used.
[0049]
In this embodiment, the component composition of the alloy material used at the start of processing contains 1 to 25% by weight of chromium and 8% by weight or less of silver or zirconium, and the balance is substantially made of copper. The chromium content rate range has the same significance as described in the first embodiment. When silver or zirconium exceeds 8% by weight, there is a tendency that the conductivity decrease due to electron scattering at the interface between these metal elements and the matrix becomes large.
[0050]
FIG. 4 shows an example of a metallographic photograph of a cast ingot of the above alloy material. It can be seen from FIG. 4 that the chrome dendrite is fine and has a favorable aspect for forming fine fibers in situ.
[0051]
As shown in FIG. 3, the cast ingot is swaged and roughed until the working degree η reaches m, then the first wire drawing is performed until the working degree η reaches n, and then the solution treatment. Then, the second wire drawing is performed. When the degree of work η reaches p, age hardening treatment for precipitation of silver or zirconium is performed, and then the second wire drawing is continued. The age hardening treatment for the precipitation of silver or zirconium is performed, for example, by heat treatment at a temperature of 200 to 450 ° C., for example, 250 ° C. for 30 to 90 minutes. This precipitation process moves from point d to point d ′, and the contribution due to precipitation hardening is superimposed.
[0052]
FIG. 5 shows an SEM image of the chromium fiber at the end of the first wire drawing (degree of processing η is 4.0). FIG. 5 was obtained by photographing with the copper matrix removed by etching and leaving only the chromium fibers. At this stage, it can be seen that the maximum diameter of the chromium fiber is coarse and the average diameter is not small.
[0053]
FIG. 6 shows an SEM image of the chromium fiber at the end of the second wire drawing (working degree η is 8.0). It can be seen from FIG. 5 that the chrome fibers are sufficiently fine.
[0054]
In this embodiment, the precipitation strengthening by silver or zirconium is superimposed together with the chromium fiber reinforcement, so that the heat treatment for precipitation does not cause the coarsening of the chromium fiber diameter and does not significantly impair the conductivity of copper. . This is because the precipitation rate of silver or zirconium in copper is relatively large, and the aging treatment for precipitation can be performed at a relatively low temperature, so that the coarsening of the chromium fiber diameter can be prevented.
[0055]
In this embodiment, both the fiber reinforcement and the precipitation of silver or zirconium contribute to the improvement of hardness, and based on this strengthening mechanism, it is possible to obtain a wire having high conductivity and high strength, particularly high bending durability. it can. Specifically, a tensile strength of 1000 MPa or more and a conductivity of 75% IACS or more can be achieved.
[0056]
Since the wire used for the movable electric wire of the present invention suppresses the deformation region to the elastic region and does not step into the plastic region, accumulation of plastic strain does not occur, and fatigue failure due to accumulation of plastic strain can be prevented. Thereby, industrial practical use of the movable electric wire of the present invention is achieved.
[0057]
In FIG. 7, the specific example of the form of the movable electric wire by this invention is shown typically.
[0058]
In FIG. 7A, reference numeral 2 denotes a wire manufactured as described in the first or second embodiment. Seven strands of this wire 2 are formed to form a stranded wire 4, and the stranded wire 4 is covered with an insulator 6 to form a covered electric wire. Examples of the material of the insulator 6 include polyethylene, polyvinyl chloride, polyester, polyurethane, and fluorine-based resin.
[0059]
In FIG.7 (b), the code | symbol 12 shows the center yarn which consists of a tetron yarn or a polyurethane yarn. Around the center yarn 12, a plurality of the stranded wires 4 described in FIG. 7 (a) are horizontally wound and covered with the insulator 6 described in FIG. 7 (a).
[0060]
In FIG. 7 (c), a plurality of wires 2 described in FIG. 7 (a) are formed in two layers around the center yarn 12 made of tetron yarn, polyurethane yarn or the like. It is coated with the insulator 6 described in (1). A plurality of horizontal windings of the wire 2 may be formed in one layer.
[0061]
Of course, the movable electric wire of the present invention is not limited to these forms, and any form may be used as long as it includes at least one wire as described above.
[0062]
FIG. 8 schematically shows a specific example of the shape of the movable cable according to the present invention.
[0063]
FIG. 8A is a perspective view, and FIG. 8B is a cross-sectional view thereof. In these drawings, reference numeral 22 denotes a central string, and reference numeral 24 denotes a covered electric wire as described in FIG. As the center string 22, for example, an aramid fiber can be used. A plurality of covered electric wires 24 are wound around the center string 22, thereby forming a linear body 26. The linear body 26 is surrounded by a sheath 28. Examples of the material of the sheath 28 include polyvinyl chloride, polyester, polyurethane, and rubber.
[0064]
Of course, the movable cable of the present invention is not limited to this form, and any form may be used as long as it includes at least one electric wire as described above. For example, the linear body 26 that does not include the center string 22, includes the inter-line interposition, or includes the air tube can be used.
[0065]
Applications suitable for the movable electric wire and the movable cable of the present invention include applications that particularly require bending durability. Examples of the industrial robot include a welding robot, a painting robot, a tube internal inspection robot, a window cleaning robot, and an underwater robot. Other applications include various machines with moving parts, such as NC controlled machine tools (lathes, milling machines, grinders, etc.), automatic warehouses with moving rods, printers with moving heads, and semiconductor device manufacturing processes. Examples of such devices (mounting machine [mounter], wafer moving machine, etc.).
[0066]
Hereinafter, the present invention will be described by way of examples.
[0067]
Example 1 :
An ingot having a composition of 10% Cr with a purity of 99.9 and the balance Cu was produced using a high-frequency vacuum melting furnace. The crucible was made of magnesia, and the mold was made of copper. The dissolution temperature was 1300 ° C. and the retention time was 10 minutes. Vacuum (5x10 until just before dissolution) ^-2 Torr) was held, and then argon was introduced to dissolve and cast. The ingot size was 30 mm in diameter and 320 mm in length, and this was chamfered to 18 mmφ. The composition analysis values of this ingot were as follows:
Cu ... 90.3wt%
Cr: 9.7wt%
C ... 17.5ppm
O ... 100.8ppm
N: 2.3 ppm.
[0068]
The processing process was based on swaging and cold drawing and drawing of hole dies. An ingot that was changed from 30 mmφ to 18 mmφ by chamfering was processed to 6.7 mmφ by swaging. At this time, the working degree η is 2.0. Next, the hole die is cold-drawn so that the degree of processing Δη at one time becomes 0.1 and is processed until the degree of processing η becomes 4.0, that is, swaging and cold drawing of the hole die and cold drawing. Were processed until the total degree of processing after total processing was 4.0. At this stage, the maximum diameter of the chromium fibers was coarse and the average diameter was not small.
[0069]
Next, a solution treatment for 30 minutes was performed at 900 ° C. when the degree of processing η was 4.0.
[0070]
Next, the hole die was cold-drawn in the same manner as described above so that the degree of processing Δη at one time was 0.1, and two types of wires having the processing degree η of 7.0 and 8.0 were obtained. . In the wire rod having a degree of processing of 7.0, the chromium fiber had a maximum diameter of 2.5 μm and an average diameter of 0.7 μm. This wire had a mechanical strength (tensile strength) measured with an Instron testing machine of 890 MPa, a length of 1 m, and a conductivity measured by the 4-terminal method of 70% IACS. Further, in the wire rod having a degree of processing of 8.0, the chromium fiber had a maximum diameter of 1.8 μm and an average diameter of 0.5 μm. This wire had a mechanical strength (tensile strength) measured by an Instron testing machine of 950 MPa, a length of 1 m, and a conductivity measured by the 4-terminal method was 65% IACS. In addition, when the solution treatment was not performed, the wire was not drawn so that the degree of processing η was 5 or more.
[0071]
Using two types of wire rods having a workability η of 7.0 and 8.0 obtained as described above, respectively, a covered electric wire as shown in FIG. ) Was manufactured. When repeatedly bending test this coated electric wire, it is superior in bending durability by 50 times or more compared with a conventional coated electric wire manufactured in the same manner using a wire made of a 0.3% tin-containing copper alloy. I understood.
[0072]
Example 2 :
An ingot having a composition of 10% Cr, 3% Ag and the balance Cu was produced using a high-frequency vacuum melting furnace. The crucible was made of magnesia, and the mold was made of copper. The dissolution temperature was 1300 ° C. and the retention time was 10 minutes. Vacuum (5x10 until just before dissolution) ^-2 Torr) was held, and then argon was introduced to dissolve and cast. The ingot size was 30 mm in diameter and 320 mm in length, and this was chamfered to 18 mmφ. The composition analysis values of this ingot were as follows:
Cu ... 87.3wt%
Cr: 9.7wt%
Ag ... 3.0wt%
C ... 11.0ppm
O ... 128.0ppm
N ··· 2.5 ppm.
[0073]
The metal structure photograph of this ingot is as shown in FIG.
[0074]
The processing process was based on swaging and cold drawing and drawing of hole dies. An ingot that was changed from 30 mmφ to 18 mmφ by chamfering was processed to 6.7 mmφ by swaging. At this time, the working degree η is 2.0. Next, the hole die was cold-drawn so that the processing degree Δη of one time became 0.1, and was processed until the processing degree η became 4.0.
[0075]
The SEM image of the chromium fiber when the degree of processing was 4.0 was as shown in FIG.
[0076]
Next, a solution treatment for 30 minutes was performed at 900 ° C. when the degree of processing η was 4.0.
[0077]
Next, the hole die was cold-drawn in the same manner as described above so that the processing degree Δη of one time became 0.1, and a wire rod having a processing degree η of 8.0 was obtained.
[0078]
The SEM image of the chromium fiber when the degree of processing was 8.0 was as shown in FIG.
[0079]
Next, an age hardening treatment was performed at 250 ° C. for 30 minutes when the degree of processing η was 8.0. The obtained wire having a degree of processing of 8.0 had a mechanical strength (tensile strength) measured by an Instron testing machine of 1000 MPa, a length of 1 m, and a conductivity measured by the 4-terminal method was 70% IACS. . In addition, when the solution treatment was not performed, the wire was not drawn so that the degree of processing η was 5 or more.
[0080]
Using the wire having a degree of work η of 8.0 obtained as described above, a covered electric wire (20 wires was wound in one layer) as shown in FIG. 7C was manufactured. When repeatedly bending test this coated electric wire, it is superior in bending durability by 50 times or more compared with a conventional coated electric wire manufactured in the same manner using a wire made of a 0.3% tin-containing copper alloy. I understood.
[0081]
Similar results were obtained when zirconium was used instead of silver in the above examples.
[0082]
【The invention's effect】
As described above, according to the present invention, the solution treatment is performed after the first wire drawing, and then the second wire drawing is performed, so that the final degree of processing can be 7 or more. Thus, it is possible to sufficiently enhance the chromium fiber reinforcement, and it is possible to provide a conductive material with improved conductivity and bending durability on an industrial scale. It is possible to provide a movable electric wire using a conductive wire having high bending durability, on an industrial scale.
[0083]
Furthermore, the present invention can provide a movable cable that has high durability against repeated bending, can be reduced in weight, has excellent mobility, and can have a long life by using the above-described movable electric wire.
[Brief description of the drawings]
FIG. 1 is a graph showing a change in hardness of a composite material accompanying a change in processing degree (progress of processing) when manufacturing a movable electric wire according to a first embodiment of the present invention.
FIG. 2 is a graph showing a change in the chromium fiber diameter with the progress of processing.
FIG. 3 is a graph showing a change in hardness of a composite material with a change in processing degree (progress of processing) when manufacturing a movable electric wire according to the second embodiment of the present invention.
FIG. 4 is a view showing an example of a metal structure of a cast ingot of an alloy material.
FIG. 5 is an SEM image showing chromium fibers at the end of the first wire drawing (working degree η is 4.0).
FIG. 6 is an SEM image showing a chromium fiber at the end of the second wire drawing (working degree η is 8.0).
FIG. 7 is a schematic view showing a specific example of the form of the movable electric wire according to the present invention.
FIG. 8 is a schematic diagram showing a specific example of the shape of the movable cable according to the present invention.
[Explanation of symbols]
2 Wire rod
4 Stranded wire
6 Insulator
12 Center thread
22 Center string
24 covered wire
26 Linear body
28 sheath

Claims (17)

Conductive wires are formed using a wire composed of a copper matrix, an in situ formed fibrous chromium in the copper matrix, and an in situ formed chromium fiber reinforced copper matrix composite material containing silver or zirconium dispersed in the copper matrix. A highly durable movable electric wire characterized by being formed. The in situ formation of chromium fiber reinforced copper matrix composite content of silver or zirconium chromium content 1-25% by weight and wherein the balance being substantially copper 0.01 to 8% by weight, wherein Item 4. The highly durable movable electric wire according to Item 1 . 3. The highly durable movable electric wire according to claim 1 , wherein the in-situ formed chromium fiber reinforced copper matrix composite material has a conductivity of 65% IACS or more and a tensile strength of 850 MPa or more. The highly durable movable electric wire according to claim 1 , wherein the wire has a wire diameter of 300 μm or less. The highly durable movable electric wire according to any one of claims 1 to 4 , wherein the conductive wire is made of a bundle of a plurality of the wires. The highly durable movable electric wire according to claim 5 , wherein the plurality of wires are twisted together. The highly durable movable electric wire according to claim 1 , wherein an insulating coating layer is attached to the conductive wire. A highly durable movable cable comprising: a linear body including at least one highly durable movable electric wire according to any one of claims 1 to 7 ; and a sheath surrounding the linear body. The alloy material consisting of 1 to 25% by weight of chromium and the balance substantially consisting of copper is subjected to a first cold wire drawing, followed by a solution heat treatment, and then a second cold wire drawing. A method for producing a highly durable movable electric wire, characterized in that a fibrous chrome is formed in situ in a copper matrix to obtain a wire, and a conductive wire is formed using at least one of the wires. An alloy material consisting of 1 to 25% by weight of chromium and a silver or zirconium content of 0.01 to 8% by weight and the balance substantially consisting of copper is subjected to a first cold wire drawing, followed by solution treatment. Then, by applying a second cold wire drawing process and then age hardening, fibrous chromium is formed in situ in the copper matrix and silver or zirconium is dispersed and precipitated in the copper matrix to obtain a wire. A method for producing a highly durable movable electric wire, wherein a conductive wire is formed using at least one of the wires. The method for producing a highly durable movable electric wire according to claim 10 , wherein the age hardening treatment is performed by heating at 200 to 450 ° C for 30 to 90 minutes. The method for producing a highly durable movable electric wire according to claim 9, wherein the alloy material is swaged before the first cold wire drawing. In the processing from the alloy material to the wire rod, when the cross-sectional area before processing is A ₀ and the cross-sectional area after processing is A and the processing degree η is defined as ln (A ₀ / A), the first wire drawing The method for producing a highly durable movable electric wire according to any one of claims 9 to 12 , wherein the processing is performed until a processing degree η from the alloy material becomes 3 to 4. In the processing from the alloy material to the wire, when the cross-sectional area before processing is A ₀ and the cross-sectional area after processing is A, and the processing degree η is defined as ln (A ₀ / A), the second wire drawing The method for producing a highly durable movable electric wire according to any one of claims 9 to 13 , wherein the processing is performed until a processing degree η from the alloy material becomes 7 or more. Each of the first wire drawing and the second wire drawing is performed by repeating a plurality of drawing operations each having a working degree η of 0.01 to 0.5. The manufacturing method of the highly durable movable electric wire in any one of Claims 13-14. The method for producing a highly durable movable electric wire according to any one of claims 9 to 15 , wherein the solution treatment is performed by heating to 780 to 1000 ° C. A linear body is formed using at least one highly durable movable electric wire manufactured by the manufacturing method according to any one of claims 9 to 16 , and the linear body is surrounded by a sheath. Manufacturing method of high durability movable cable.

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