Copper alloy wire, cable, and method for producing copper alloy wire
阅读说明：本技术 铜合金线、电缆以及铜合金线的制造方法 (Copper alloy wire, cable, and method for producing copper alloy wire ) 是由 高桥和久 秦昌平 黑田洋光 鹫见亨 西和也 藤户启辅 辻隆之 于 2019-08-14 设计创作，主要内容包括：本发明提供铜合金线、电缆以及铜合金线的制造方法,能够不降低由含有锆等的铜合金形成的铜合金线的导电率且提高铜合金线的弯曲特性。电缆(11)具有双芯绞线、设置在上述双芯绞线周围的介在物(3)、和设置在介在物(3)周围的护套(4),该双芯绞线通过将2根电线(10)绞合而成,该电线(10)由导体(1)和被覆于导体(1)周围的绝缘层(2)构成,导体(1)是分散有含锆的析出物的铜合金线,晶体粒径为1μm以下,导电率为87％IACS以上,拉伸强度为545MPa以上。(The invention provides a copper alloy wire, a cable and a method for manufacturing the copper alloy wire, which can improve the bending property of the copper alloy wire without reducing the conductivity of the copper alloy wire formed by the copper alloy containing zirconium and the like. A cable (11) is provided with a twin-core twisted wire, an intervening object (3) provided around the twin-core twisted wire, and a sheath (4) provided around the intervening object (3), wherein the twin-core twisted wire is formed by twisting 2 wires (10), the wires (10) are composed of a conductor (1) and an insulating layer (2) coated around the conductor (1), the conductor (1) is a copper alloy wire in which precipitates containing zirconium are dispersed, the crystal grain size is 1 [ mu ] m or less, the electrical conductivity is 87% IACS or more, and the tensile strength is 545MPa or more.)
1. A method of manufacturing a copper alloy wire, comprising:
(a) a step of forming a copper material in a supersaturated solid solution state by subjecting a copper material containing zirconium to solution treatment;
(b) a step of forming a first wire material by drawing the copper material in a supersaturated solid solution state after the step (a);
(c) forming a first copper alloy wire by heat-treating the first wire material after the step (b);
(d) forming a second wire material by drawing the first copper alloy wire after the step (c);
(e) a step of forming a second copper alloy wire having a copper crystal grain size of 1 μm or less by heat-treating the second wire material after the step (d),
wherein the content of the first and second substances,
in the step (c), first precipitates containing zirconium are precipitated in the first copper alloy wire,
in the step (d), the first precipitates are dispersed in the second wire rod,
in the step (e), the second wire is heat-treated at 350 to 400 ℃, and second precipitates containing zirconium are precipitated in the second copper alloy wire.
2. The method for producing a copper alloy wire according to claim 1,
the copper material is a copper material in which zirconium is in a solid-soluble state in copper.
3. The method for producing a copper alloy wire according to claim 1 or 2,
in the step (c), the first wire material is heat-treated at 350 to 400 ℃.
4. The method for producing a copper alloy wire according to any one of claims 1 to 3,
the zirconium content in the copper material is 200 ppm by weight or more and 2000 ppm by weight or less.
5. The method for producing a copper alloy wire according to any one of claims 1 to 4,
the second copper alloy wire has an electrical conductivity of 87% IACS or more.
6. The method for producing a copper alloy wire according to any one of claims 1 to 5,
the tensile strength of the second copper alloy wire is 545MPa or more.
7. The method for producing a copper alloy wire according to claim 6,
the diameter of the second copper alloy wire is 0.08 mm.
8. A kind of copper alloy wire is provided,
in which a precipitate containing zirconium is dispersed,
the crystal grain diameter of copper is less than 1 μm,
the electric conductivity is more than 87 percent IACS,
the tensile strength is 545MPa or more.
9. The copper alloy wire according to claim 8,
the diameter of the copper alloy wire is 0.08 mm.
10. A cable having a conductor formed of the copper alloy wire according to claim 8 or 9.
Technical Field
The present invention relates to a copper alloy wire, a cable, and a method for manufacturing a copper alloy wire.
Background
Conventionally, copper alloy wires made of copper alloys have been used as conductors constituting electric wires and cables. For example,
Disclosure of Invention
Problems to be solved by the invention
The electric wire and cable used for the movable portion require a conductor having high conductivity and bending characteristics that are less likely to break when repeatedly bent. However, in a copper alloy wire formed of a copper alloy containing zirconium or the like, it is difficult to improve the bending characteristics while maintaining high conductivity, and improvement is desired. That is, if a copper alloy wire made of a copper alloy containing zirconium or the like is improved so as to be less likely to break when repeatedly bent, the electrical conductivity may be reduced.
The present invention has been made in view of the above problems, and an object of the present invention is to improve the bending characteristics of a copper alloy wire formed of a copper alloy containing zirconium or the like without lowering the electrical conductivity of the copper alloy wire.
Means for solving the problems
A brief description will be given of an outline of a representative one of the inventions disclosed in the present application, as follows.
[1] A method of manufacturing a copper alloy wire, comprising: (a) a step of forming a copper material in a supersaturated solid solution state by subjecting a copper material containing zirconium to solution treatment; (b) a step of forming a first wire material by drawing the copper material in a supersaturated solid solution state after the step (a); (c) forming a first copper alloy wire by heat-treating the first wire material after the step (b); (d) forming a second wire material by drawing the first copper alloy wire after the step (c); (e) and (d) heat-treating the second wire material after the step (d) to form a second copper alloy wire having a copper crystal grain size of 1 μm or less. And, in the step (c), first precipitates containing zirconium are precipitated in the first copper alloy wire, in the step (d), the first precipitates are dispersed in the second wire, and in the step (e), the second wire is heat-treated at 350 to 400 ℃ to precipitate second precipitates containing zirconium in the second copper alloy wire.
[2] The method for producing a copper alloy wire according to [1], wherein the copper material is a copper material in which zirconium is dissolved in copper.
[3] The method of manufacturing a copper alloy wire according to [1] or [2], wherein the first wire material is heat-treated at 350 to 400 ℃ in the step (c).
[4] The method for producing a copper alloy wire according to any one of [1] to [3], wherein the content of zirconium in the copper material is 200 ppm by weight or more and 2000 ppm by weight or less.
[5] The method for producing a copper alloy wire according to any one of [1] to [4], wherein the second copper alloy wire has an electrical conductivity of 87% IACS or more.
[6] The method for producing a copper alloy wire according to any one of [1] to [5], wherein the tensile strength of the second copper alloy wire is 545MPa or more.
[7] The method for producing a copper alloy wire according to [6], wherein the second copper alloy wire has a diameter of 0.08 mm.
[8] A copper alloy wire having a precipitate containing zirconium dispersed therein, wherein the crystal grain size of copper is 1 [ mu ] m or less, the electrical conductivity is 87% IACS or more, and the tensile strength is 545MPa or more.
[9] The copper alloy wire according to [8], wherein the diameter of the copper alloy wire is 0.08 mm.
[10] A cable comprising a conductor formed of the copper alloy wire according to [8] or [9 ].
Effects of the invention
According to the present invention, the electrical conductivity of a copper alloy wire made of a copper alloy containing zirconium or the like can be reduced, and the bending characteristics of the copper alloy wire can be improved.
Drawings
Fig. 1 is a flowchart showing a manufacturing process of a copper alloy wire according to an embodiment.
Fig. 2 is a cross-sectional view showing a cable structure of an embodiment.
Fig. 3 is a graph showing a crystal grain size distribution of the copper alloy wire according to the embodiment.
Fig. 4 is a graph showing the results of a bending test of the copper alloy wire according to the embodiment.
Description of the symbols
1: conductor, 2: insulating layer, 3: intervene, 4: sheath, 10: electric wire, 11: an electrical cable.
Detailed Description
(matters of study)
< previous study >
First, matters studied by the present inventors will be described before describing the embodiments. As described above, a copper alloy wire made of a copper alloy is used as a conductor constituting an electric wire or a cable. Since high mechanical strength is required for electric wires and cables, it is desired to improve the mechanical strength of copper alloy wires. As a method for improving the mechanical strength of the copper alloy wire, there is a solid solution strengthening method. This solid solution strengthening method is a method for improving the mechanical strength of a copper alloy wire by utilizing the principle that solute atoms (impurity atoms) solid-dissolved in the crystal structure of solvent atoms (copper atoms) or at lattice positions inhibit the movement of dislocations. However, in the case of a copper alloy wire having improved mechanical strength by the solid solution strengthening method, solute atoms (impurity atoms) enter solvent atoms (copper atoms) at an atomic level, and therefore it is difficult to ensure the original electrical conductivity of copper, and the electrical conductivity is greatly reduced. That is, it is difficult to improve the mechanical strength of the copper alloy wire while securing the electrical conductivity of the copper alloy wire by the solid solution strengthening method.
Therefore, hereinafter, improvement of the mechanical strength of the copper alloy wire while securing the electrical conductivity of the copper alloy wire by the precipitation strengthening method is studied.
First, an outline of the precipitation strengthening method will be described. In order to apply the precipitation strengthening method, it is necessary to perform (a) a solution treatment step and (b) a heat treatment (precipitation) step.
The solution treatment is a heat treatment technique in which the alloy is rapidly cooled from a high temperature to a normal temperature, thereby maintaining the metal structure developed at the high temperature even at the normal temperature. In particular, in the precipitation strengthening method, it is important to rapidly cool the steel sheet in a solid solution state to form a supersaturated solid solution. Therefore, the solution treatment is also called forced solid solution.
Next, the supersaturated solid solution is subjected to a heat treatment step, whereby the intermetallic compound is gradually precipitated in the matrix. The amount of precipitates increases with time, and the properties of the alloy gradually change. Therefore, such heat treatment is also referred to as aging treatment. As described above, the precipitates precipitated in the matrix act as dislocation movement inhibitors, and thus the mechanical strength of the alloy is strengthened.
When the above-described precipitation strengthening method is applied to a copper alloy wire, it is examined how to combine (a) a solution treatment step and (b) a heat treatment step in a manufacturing step of the copper alloy wire.
The copper alloy wire production process includes (1) a casting process, (2) a rolling process, and (3) a wire drawing process. In the casting step (1), a cast material of a copper alloy is formed, and in the rolling step (2), the cast material is rolled by hot rolling or the like to form a rolled material, which will be described in detail later. Then, in the drawing step (3), the rolled material is drawn by, for example, cold drawing to form a drawn wire.
First, in order to apply the precipitation strengthening method to a copper alloy wire, it has been studied to perform (a) a solution treatment step and (b) a heat treatment step after (3) a wire drawing step in a method for producing a copper alloy wire. However, it is known that the mechanical strength of the copper alloy wire obtained by this manufacturing method is not high. The reason for this was investigated as follows.
First, the copper alloy is drawn by the drawing step (3), and as a result, stress strain is generated in the crystal of the matrix. Then, the copper alloy is heated in the heat treatment step (b), and the stress remaining in the copper alloy wire in the wire drawing step (3) is released. This promotes recrystallization of the matrix copper, and the crystal grain size of the matrix is increased compared to that before the heat treatment step. Here, it is known that the following Hall-Petch (Hall-Petch) formula is empirically established as a relationship between the crystal particle diameter and the mechanical strength.
"σ y" represents the yield mechanical strength (yield stress) of the material, "
According to the Hall-Petch formula, the smaller the crystal grain size is, the larger the yield stress is. That is, it is considered that the crystal grain size of copper is increased by performing the heat treatment step (b) after the wire drawing step (3), and as a result, the yield stress is reduced. Therefore, if (a) the solution treatment step and (b) the heat treatment step are performed after (3) the wire drawing step, the crystal grain size of copper increases due to recrystallization of copper, and the mechanical strength of the copper alloy wire cannot be improved.
Next, in order to apply the precipitation strengthening method to the copper alloy wire, it has been studied to perform (a) a solution treatment step and (b) a heat treatment step after (2) a rolling step in a manufacturing method of the copper alloy wire, and to perform (3) a wire drawing step thereafter. As a result of the studies by the present inventors, it was found that (3) the drawing step causes the copper alloy to be drawn, and as a result, stress strain is generated in the crystal of the matrix, and the crystal grain size of the matrix becomes smaller than that before the drawing step. From the above Hall-Petch formula, it is found that the yield stress is increased as the polycrystalline material is composed of fine crystal grains. This corresponds to an increase in strength by grain refinement. That is, the strengthening by grain refinement is a method of increasing the mechanical strength of an alloy by reducing the grains constituting the alloy based on the increase in yield stress as the polycrystal formed of fine grains becomes larger.
It is understood that, in the case where (2) the rolling step is followed by (a) the solution treatment step and (b) the heat treatment step, and then (3) the wire drawing step in the method for producing a copper alloy wire, the electrical conductivity of the copper alloy wire is significantly reduced. The reason for this is considered to be: by performing (a) the solution treatment step and (b) the heat treatment step as described above and performing (3) the wire drawing step in a state where precipitates are precipitated in the matrix, the crystal grain size of the matrix becomes excessively small, and as a result, the conductivity is significantly reduced. Therefore, if (a) the solution treatment step and (b) the heat treatment step are performed after (2) the rolling step, and then (3) the wire drawing step is performed, the electrical conductivity of the copper alloy wire cannot be improved.
As a result of the studies on the method for producing a copper alloy wire as described above, it is desired to apply a precipitation strengthening method and an increase in strength by grain refinement to a copper alloy wire, suppress a decrease in electrical conductivity of the copper alloy wire, and improve the mechanical strength of the copper alloy wire.
(embodiment mode)
< method for manufacturing copper alloy wire of the present embodiment >
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings showing the embodiments, the same or similar parts are denoted by the same or similar reference numerals or symbols, and description thereof will not be repeated in principle.
Fig. 1 is a flowchart showing a process for manufacturing a copper alloy wire according to the present embodiment. As shown in fig. 1, the manufacturing process of the copper alloy wire according to the present embodiment includes a casting process (S11), a rolling process (S12), a solution treatment process (S13), a wire drawing process (S14), a heat treatment (precipitation) process (S15), a wire drawing process (S16), and a heat treatment (precipitation) process (S17). The specific steps of each step will be described below.
First, a casting step is performed (S11). For example, pure copper (Cu) such as oxygen-free copper is heated to about 1150 ℃ in a crucible. This melts the pure copper to form molten copper. Next, a copper-zirconium (Zr) master alloy (for example, 50 wt% of copper: zirconium: 50 wt%) is added to the molten copper in the crucible. Thereby, molten copper containing zirconium is formed. In this case, the addition amount of the copper-zirconium master alloy is preferably adjusted so that the zirconium content in the molten copper is 200 ppm by weight or more and 2000 ppm by weight or less (0.02% by weight or more and 0.20% by weight or less). In particular, the content of zirconium in molten copper is more preferably set to 1000 ppm by weight (0.10% by weight) or more and 2000 ppm by weight or less, so that in a copper alloy wire having a diameter of 0.05mm or more and 0.20mm or less, the electrical conductivity can be easily set to 87% IACS or more in a state where precipitates formed of a copper-zirconium compound are uniformly dispersed in copper. Particularly, if the zirconium content in the molten copper is 1400 ppm by weight (0.14 wt%), the conductivity is more preferably 87% IACS or more in a state where the copper-zirconium compound is precipitated. Here, the reason why zirconium is selected as an additive to copper is that even if zirconium is added to copper, a decrease in the electrical conductivity of copper is not substantially observed. The third component is not particularly limited as long as the third component does not lower the electrical conductivity of copper even when added to copper, and examples of the third component include metals contained in copper other than zirconium or metals contained in copper, such as titanium (Ti) and chromium (Cr).
Next, molten copper containing zirconium is poured from the crucible into a mold. Then, the mold is water-cooled to form a cylindrical casting material (ingot) having a diameter of, for example, 30 mm. This completes the casting step (S11).
The method of forming the zirconium-containing molten copper is not limited to the above-described method, and may be a method of forming zirconium-containing molten copper by heating copper and zirconium together, or a method of forming zirconium-containing molten copper by adding only zirconium to molten copper. However, from the viewpoint of stable yield of the alloy, a method of adding a copper-zirconium mother alloy to molten copper is preferable as a method of forming molten copper containing zirconium.
Next, a rolling step (S12) is performed. The cast material formed in the casting step (S11) is hot-rolled at, for example, about 800 ℃ to form a cylindrical rolled material having a diameter of 12 mm. After the hot rolling, the rolled material is slowly cooled by air cooling to obtain a copper material. This completes the rolling step (S12).
Next, a solution treatment step (S13) is performed. The copper material formed in the rolling step (S12) is heated at about 850 ℃ for 1.5 hours, and then quenched by water cooling. As the quenching condition, the copper material with the temperature of 800-900 ℃ is preferably cooled to the temperature of 15-20 ℃ by water within the time of 5-10 seconds. Thereby, the copper material reaches a state of supersaturated solid solution. When the solution treatment requires a long time, it is preferable to perform the solution treatment in a state where the copper material after the slow cooling is wound when the solution treatment is performed on the copper material. This step is a solution treatment step (S13). In the solution treatment step (S13), the solution treatment may be performed by a method other than cooling with water.
Here, specific conditions of the solution treatment step (S13) will be described. In a copper material formed of an alloy of copper and zirconium, when the content of zirconium in the alloy is 2000 ppm by weight or less, a solid solution state is formed in which zirconium is dissolved in copper at a temperature of about 800 to 1100 ℃. At a temperature above this range (e.g., 1200 ℃), copper and zirconium melt. At a temperature below this temperature (e.g., 700 ℃), zirconium is dissolved in copper. In order to achieve such a state, for example, when a copper material containing zirconium is heated to about 850 ℃, a solid solution state is formed in which zirconium is solid-dissolved in copper. Then, the copper material in the solid solution state is subjected to rapid cooling (quenching) treatment, so that the zirconium-containing copper material is in a supersaturated solid solution state.
As a result of the studies by the present inventors, it has been found that if the heating temperature of the copper material in the solution treatment step (S13) is set to 900 ℃ or higher, the crystal size of the base material (copper) may be coarsened. Therefore, the heating temperature of the copper material in the solution treatment step (S13) is preferably 800 to 900 ℃. Further, since zirconium in copper rapidly diffuses at a high temperature of about 800 ℃, fine precipitates formed of a copper-zirconium compound are likely to precipitate when the copper material is cooled by water cooling without furnace cooling. Therefore, the cooling of the copper material is preferably performed by water cooling.
Next, a wire drawing step (S14) is performed. The copper material (diameter 12mm) which has reached the supersaturated solid solution state through the solution treatment step (S13) is drawn, for example, by a die to form a drawn wire material (first wire material) (diameter 0.26 mm). As described above, the copper material is drawn in the wire drawing step (S14), so that the crystal grain size of the matrix becomes smaller than that before the wire drawing step. This step is the drawing step (S14).
Next, a heat treatment (deposition) step is performed (S15). Heating the drawn wire formed through the drawing step (S14) at 350 to 400 ℃ for 1 hour. By thus heat-treating the wire rod in the supersaturated solid solution state, precipitates (first precipitates, intermetallic compound of copper and zirconium) are gradually precipitated in the matrix (copper). The amount of precipitates increases with time, and the characteristics of the copper containing zirconium gradually change. Therefore, such heat treatment is also called aging treatment. In this step, since the wire rod is heated from room temperature, the diffusion of zirconium in copper is slower than that in the high temperature, and the copper-zirconium compound is finely precipitated in the matrix. The above is the heat treatment step (S15), and the drawn wire after the heat treatment step (S15) becomes a copper alloy wire (first copper alloy wire).
Next, in the wire drawing step (S16), the wire rod (diameter 0.26mm) from which the precipitates (copper-zirconium compound) were precipitated through the heat treatment (precipitation) step (S15) was drawn by, for example, a die to form a wire rod (second wire rod) (diameter 0.08 mm). This step is the drawing step (S16).
Next, in the heat treatment (precipitation) step (S17), the wire rod formed through the wire drawing step (S16) is heated at 350 to 400 ℃ for 1 hour, as in the heat treatment (precipitation) step (S15). Thereby, precipitates (second precipitates, intermetallic compound of copper and zirconium) are gradually precipitated in the matrix (copper). The above is the heat treatment (deposition) step (S17), and the drawn wire after the heat treatment step (S17) becomes a copper alloy wire (second copper alloy wire). In the wire drawing step, the diameter of the wire drawing material can be appropriately changed to make the diameter of the obtained copper alloy wire in the range of 0.05mm to 0.20 mm.
As described above, the copper alloy wire according to the present embodiment can be produced through the casting step (S11) to the heat treatment step (S17).
The precipitates precipitated in the heat treatment (precipitation) step (S15) may be the same as or different from the precipitates precipitated in the heat treatment (precipitation) step (S17).
< main features and effects of the present embodiment >
One of the main features of the present embodiment is that a wire drawing step (S14) is provided between the solution treatment step (S13) and the heat treatment (deposition) step (S15) in the method for producing a copper alloy wire. Further, after the heat treatment (deposition) step (S15), there are provided a wire drawing step (S16) and a heat treatment (deposition) step (S17).
As described above, if the solution treatment step and the heat treatment step are performed after the wire drawing step in the method for producing a copper alloy wire, the crystal grain size of the matrix (copper) becomes too large, and the mechanical strength of the copper alloy wire cannot be improved.
On the other hand, if the solution treatment step and the heat treatment step are performed after the rolling step in the method for producing a copper alloy wire, and then the wire drawing step is performed, the crystal grain size of the matrix (copper) becomes too small, and therefore, the conductivity of the copper alloy wire cannot be improved.
Here, in the present embodiment, by performing the solution treatment (S13) → the drawing step (S14) → the heat treatment step (S15) in this order, the crystal grain size of the matrix (copper) becomes small in the drawing step (S14), but the recrystallization of the matrix (copper) proceeds through the heat treatment step (S15), and the crystal grain size becomes large. At the same time, since precipitates formed of the copper-zirconium compound are precipitated in the heat treatment step (S15), the crystal growth is suppressed by the precipitates, and the crystal grain size of the matrix (copper) does not become too large. That is, the crystal grain size of the matrix (copper) after the heat treatment step (S15) is smaller than that before the wire drawing step (S14). As described above, in the present embodiment, the crystal growth is suppressed by the precipitates (copper-zirconium compound) precipitated in the matrix (copper), and the crystal grain size of the matrix in the copper alloy wire is optimized.
As described above, in the present embodiment, the precipitates (copper-zirconium compound) precipitated in the matrix (copper) act as an inhibitor of dislocation movement, and therefore the mechanical strength of the copper alloy wire is improved as compared with the case where no precipitates are contained.
In addition, in the present embodiment, since the second drawing step (S16) and the second heat treatment step (S17) are provided after the heat treatment step (S15), the second drawing step (S16) can be performed in a state where precipitates (copper-zirconium compound) are precipitated in the matrix (copper). By doing so, the precipitates are widely dispersed throughout the matrix (copper) through the wire drawing step (S16). In this case, the precipitates are preferably not locally agglomerated. Further, the precipitates are further precipitated in the matrix (copper) through the second heat treatment step (S17). As a result, in the present embodiment, the amount of precipitates in the matrix is increased as compared with the case where the heat treatment step is performed only once, and the precipitates precipitated through the heat treatment step (S17) are dispersed widely in the matrix without being aggregated while maintaining the state where the precipitates are dispersed widely throughout the matrix (copper) through the wire drawing step (S16), so that the mechanical strength of the copper alloy wire is improved. Thus, in the present embodiment, a copper alloy wire having a tensile strength of 545MPa or more can be obtained.
In the present embodiment, a second wire drawing step (S16) is provided between the first heat treatment step (S15) and the second heat treatment step (S17). If the heat treatment process is continuously performed twice, the crystal grain size of the matrix (copper) becomes excessively large, and the mechanical strength of the copper alloy wire is lowered. Therefore, the crystal grain size of the matrix (copper) is temporarily reduced by performing the second wire drawing step (S16) after the first heat treatment step (S15). Then, the second heat treatment step (S17) is performed to increase and optimize the crystal grain size of the matrix (copper) again. As a result, the mechanical strength of the copper alloy wire can be further improved without lowering the electrical conductivity of the copper alloy wire as compared with the case where the heat treatment step is performed only once.
As described above, according to the method for manufacturing a copper alloy wire of the present embodiment, the precipitation strengthening method can be combined with the strengthening by grain refinement, and the mechanical strength of the copper alloy wire can be improved without lowering the electrical conductivity of the copper alloy wire.
As another embodiment, after the heat treatment (deposition) step (S17) in the present embodiment, the wire drawing step and the heat treatment (deposition) step may be repeated a plurality of times. In this case, the precipitates in the matrix can be precipitated more than in the present embodiment, and the precipitates in the matrix can be dispersed more widely. However, according to the studies of the present inventors, it was found that even if the number of times of performing the wire drawing step and the heat treatment (precipitation) step is increased to the above number, the amount of precipitates is saturated and the mechanical strength of the copper alloy wire is not improved. Therefore, the present embodiment can be said to be most preferable in view of the manufacturing cost.
From the viewpoint of obtaining a copper alloy wire having the tensile strength, the heat treatment (heating) temperature in the heat treatment (deposition) step (S17) needs to be 350 to 400 ℃ in order to optimize the crystal grain size of the matrix (copper) (to 1 μm or less), and it is preferable that the heat treatment (heating) temperature in the heat treatment (deposition) step (S15) is the same as the heat treatment (deposition) step (S17).
In the present embodiment, the content of zirconium is preferably 200 ppm by weight or more and 2000 ppm by weight or less. The present inventors have confirmed that, by setting the zirconium content to the above range, the conductivity is high (87% IACS or more) and the resistance to repeated bending is excellent (even if the conductor is repeatedly bent 1 ten thousand or more, the conductor is not broken). In particular, in the copper alloy wire according to the present embodiment, by setting the content of zirconium to a range of 1000 ppm by weight or more and 2000 ppm by weight or less in the above-described content of zirconium, in the copper alloy wire according to the present embodiment, zirconium solid-dissolved in copper is precipitated as precipitates (copper-zirconium compound), so that the purity of copper is easily brought close to the state of pure copper, and the precipitated fine precipitates (copper-zirconium compound) are easily uniformly dispersed in copper. Therefore, the copper alloy wire according to the present embodiment can simultaneously have the characteristics of having the electrical conductivity of 87% IACS or more and the tensile strength of 545MPa or more when the diameter is 0.05mm or more and 0.20mm or less, and is excellent in resistance to repeated bending.
In the present embodiment, it is also conceivable to omit the solution treatment step (S13) in order to reduce the cost. However, the cast material formed through the casting step (S11) is in a state in which coarse copper-zirconium compounds are dispersed. Therefore, if the heat treatment step (S15) is performed without performing the solution treatment step (S13), the precipitates may not be uniformly dispersed, and the precipitates may not be precipitated in the matrix from the beginning. Therefore, the method for producing a copper alloy wire preferably includes a solution treatment step (S13).
< Cable Using copper alloy wire >
Fig. 2 is a schematic view showing a cable using a copper alloy wire according to an embodiment of the present invention.
As shown in fig. 2, a cable 11 according to the present embodiment includes a two-core twisted wire formed by twisting 2
As the conductor 1 constituting the cable 11 of the present embodiment, a copper alloy wire manufactured by the method for manufacturing a copper alloy wire of the above-described embodiment is used. As described later, the copper alloy wire produced by the method for producing a copper alloy wire according to the above embodiment is a copper alloy wire in which precipitates containing zirconium are dispersed, and has a crystal grain size of 1 μm or less and an electrical conductivity of 87% IACS or more. As the conductor 1, a stranded conductor obtained by stranding the copper alloy wires manufactured by the method for manufacturing a copper alloy wire according to the above embodiment may be used.
The cable 11 of the present embodiment is manufactured, for example, as follows. First, a copper alloy wire obtained by the above-described manufacturing method is prepared as the conductor 1. Then, a fluororesin, a polyvinyl chloride resin, a silicone rubber, or the like is formed by an extruder into the insulating
Note that, although the cable 11 of the present embodiment has been described as an example in which a twisted twin wire obtained by twisting 2
< characteristics of copper alloy wire >
Hereinafter, characteristics of the copper alloy wire manufactured by the method for manufacturing a copper alloy wire according to the above embodiment will be described. In examples 1 to 2 and comparative examples 1 to 4 below, in the production process shown in fig. 1, a copper-zirconium master alloy was added to molten copper so that the content of zirconium in the molten copper was 1400 ppm by weight to form a cast product, the cast product was hot-rolled at a hot rolling temperature of about 800 ℃ to form a rolled product (diameter: about 12mm), and the rolled product was slowly cooled to obtain a copper product. The copper material is subjected to solution treatment at a temperature of about 850 ℃ to form a copper material in a supersaturated solid solution state, and the copper material in the supersaturated solid solution state is subjected to wire drawing until the diameter becomes 0.26mm, and then subjected to heat treatment at a heat treatment temperature of 350 ℃ to form a first copper alloy wire. The first copper alloy wire was wire-drawn until the diameter became 0.08mm, and then heat-treated at the heat treatment temperature shown in table 1 to form a second copper alloy wire. The second copper alloy wire is a copper alloy wire containing about 1300 ppm by weight of zirconium, with the balance being copper and unavoidable impurities.
Table 1 is a table showing the relationship between the electrical conductivity, tensile strength, and 0.2% proof stress of the copper alloy wire manufactured by the method for manufacturing a copper alloy wire according to the above embodiment and the heat treatment temperature in the manufacturing process. Fig. 3 is a graph showing a crystal grain size distribution of the copper alloy wire according to the above embodiment. Fig. 4 is a graph showing the results of a bending test of the copper alloy wire according to the above embodiment.
TABLE 1
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种热镀铝锌钢板的生产方法