JPH1150215A - Production of high strength and high electric conductivity copper alloy and copper alloy wire rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper alloy and a copper alloy wire rod realizing high strength and high electric conductivity and having excellent cold workability by casting an ingot of a copper alloy having a compsn. contg. specified ratios of oxygen and silver, and the balance copper with inevitable impurities and thereafter executing cooling at a cooling rate in a specified range. SOLUTION: The oxygen concn. of the copper alloy is regulated to 0.1 to 0.45 wt.%, and the silver concn. is regulated to 0.05 to 5 wt.%. In this way, copper in which cuprous oxide particles crystallized out at the time of solidification are finely dispersed at high density and dispersedly strengthened can be obtd. Furthermore, it is added with silver to form a Cu-Ag solid solution, which is subjected to solid solution strengthening, by which a copper alloy furthermore having higher strength can be obtd. Then, the cooling rate after casting is regulated to 3 to 100 deg.C/sec, preferably to the range of 10 to 30 deg.C/sec. In this way, the coarsening of the oxide particles is suppressed to increase its strength owing to the dispersion of the fine oxide particles. This copper alloy is subjected to wire drawing, by which the copper alloy wire rod having high strength and high electric conductivity can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a copper alloy and a copper alloy wire suitable for a conductor for electric wires requiring high strength and electrical conductivity.

[0002]

2. Description of the Related Art Conventionally, pure copper and diluted copper alloys have been used as conductor materials for various electric wires. In recent years, in order to improve the performance and function of electric wires, they have to have higher strength and electrical conductivity. Is required. In general, methods for increasing the strength of pure copper, copper alloys, and the like include a method of giving a high working rate in the process of forming a wire and work hardening, a method of adding an alloy element, a method of finely dispersing an oxide, and the like. . Examples of the method include a powder metallurgy method in which fine metal powder and fine oxide powder are mixed and sintered, and an internal oxidation method in which an additive element dissolved in a matrix is oxidized by heat treatment.

[0003]

The method described above requires processing the wire rod until the wire diameter becomes small. If the final wire diameter cannot be so reduced, it is necessary to increase the initial wire diameter. In any case, there is a drawback that the applicable wire size is greatly restricted. In the method (1), there is a trade-off relationship between strength and conductivity due to the addition of an alloy element, in which one improves and the other decreases, and it is difficult to achieve both. In addition, when precipitation strengthening is used, a two-step heat treatment step of solution treatment and aging is required, so that the cost is increased. The above methods have the disadvantage that the steps are complicated and the amount that can be produced at one time is limited.

The present invention has been made to solve the above problems, and realizes high strength and high electrical conductivity by dispersing fine cuprous oxide particles at a high density, and has excellent cold workability. An object of the present invention is to provide a method for producing a high-strength high-conductivity copper alloy and a copper alloy wire having the same.

[0005]

The high-strength and high-conductivity copper alloy according to the present invention contains 0.1 to 0.45% by weight of oxygen and 0.05 to 5% by weight of silver, with the balance being copper. And an ingot of copper alloy consisting of unavoidable impurities, 3 to 1 after casting
It is manufactured by cooling at a cooling rate of 00 ° C./sec. The method for producing a high-strength and high-conductivity copper alloy wire according to the present invention comprises 0.1 to 0.45% by weight of oxygen and 0.05 to 5% by weight of silver, and the balance consists of copper and unavoidable impurities. Ingot of copper alloy
After being manufactured by cooling at a cooling rate of from 100 ° C./sec to 100 ° C./sec, the wire is drawn.

The present inventors have studied the oxygen concentration in copper and the casting conditions, and found that the oxygen concentration was 0.1 to 0.4.
By setting the content in the range of 5% by weight, it has been clarified that oxide (copper oxide) particles crystallized during solidification are finely and densely dispersed to obtain dispersion-strengthened copper. Furthermore, silver (Ag) is added to copper (Cu), and Cu (Cu) is added.
It has been clarified that a copper alloy having higher strength can be obtained by forming a solid solution of -Ag and strengthening the solid solution. When the oxygen concentration is lower than 0.1% by weight, the dispersion density of the oxide particles is low, and the strength is not sufficiently increased. Conversely, when the oxygen concentration is 0.
Above 45% by weight, coarse oxides crystallize, which reduces the ductility of the material and makes cold working difficult. On the other hand, if the cooling rate immediately after casting is lower than 3 ° C./sec, the oxide particles become coarse and the effect of dispersion strengthening cannot be obtained. It has also been confirmed that the effect can be obtained at a cooling rate of 100 ° C./sec. Preferably, by setting the cooling rate to 10 to 30 ° C./sec, coarsening of the oxide particles is suppressed, and high strength is achieved by fine oxide particle dispersion. If the concentration of silver is lower than 0.05% by weight, a sufficient solution effect by silver cannot be obtained, and if it exceeds 5% by weight, the processability is lowered and the wire drawing as a wire becomes difficult.

[0007]

Embodiments of the present invention will be described below. Using an alumina crucible, oxygen-free copper as a raw material,
After melting at a temperature of about 1200 ° C in the atmosphere, 24mmφ
Into an ingot of about 3 kg.
Simultaneously with the dissolution, Cu-O and granular silver (Ag) were added to prepare samples in which the oxygen concentration and the Ag concentration were variously changed. However, for a sample (Comparative Example 1) that obtains an oxygen concentration at a normal tough pitch copper level, a carbon crucible was used, and no Cu-O was added. In addition, samples were prepared with various cooling rates immediately after casting. The cooling rate was controlled by cooling (or heating) the mold. Specifically, the cooling rate was determined by attaching a thermocouple to the mold and recording the time change of the temperature. In the case of the embodiment, a melting furnace for batch processing is used. In this case, the crucible is air-cooled at 3 to 100 ° C./sec.
Although a cooling rate of c can be obtained, in the case of continuous casting using a vacuum melting furnace, a cooling rate in the above range can be obtained by cooling by gas spraying using liquid N ₂ or CO _2. is there.

Thereafter, each ingot was swaged and drawn at room temperature, processed to 6.4 mmφ, and then annealed at 500 ° C. for 1 hour. This annealing can be used in the hot working step, but is preferably 800 ° C. or lower in order to prevent the oxide from becoming coarse. For each sample after annealing, wire drawing was further performed at room temperature at a processing rate of 90%.

Each sample was evaluated for tensile strength and electrical conductivity. The results are shown in Table 1 below. The cold workability was evaluated as follows: た indicates that the wire was not broken by wire drawing with a working ratio of 90%, and the wire was broken in the middle of the working ratio of 90%. △, processing rate 90
When the wire drawing process of% was impossible, it was evaluated as x.

[0010]

[Table 1]

From Table 1, it can be seen that Examples 1 to 3 containing an appropriate amount of oxygen and Ag had an oxygen content of Ag at the tough pitch copper level.
In comparison with Comparative Example 1 containing no, the tensile strength was high and the decrease in conductivity was suppressed to 5% or less. Comparative Example 2 has a higher oxygen concentration than Comparative Example 1, but lower than Examples 1 to 5,
0.07% by weight and does not contain Ag, so that the tensile strength is lower than those of Examples 1 to 3. In Comparative Examples 3 and 4, the ductility was reduced because the oxygen concentration was too high, and the processing rate was 9%.
0% wire drawing was not possible. Comparative Example 5 in which oxygen and Ag were slightly added had higher tensile strength than Comparative Examples 1 to 4 in which Ag was not added, but was still insufficient. In Comparative Example 6 in which the Ag concentration was too high, workability was poor, and wire drawing at a work ratio of 90% was impossible.

[0012]

As described above, according to the present invention,
A copper ingot containing 0.1 to 0.45% by weight of oxygen and 0.05 to 5% by weight of silver, the balance being copper and unavoidable impurities, is cooled at 3 to 100 ° C./sec after casting. After being manufactured by cooling at a high speed, a copper alloy wire having high strength and high conductivity can be obtained by wire drawing.

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Claims (2)

[Claims] 1. A copper alloy ingot containing 0.1 to 0.45% by weight of oxygen and 0.05 to 5% by weight of silver and the balance of copper and unavoidable impurities is cast from 3 to 10% after casting.
A high-strength, high-conductivity copper alloy produced by cooling at a cooling rate of 0 ° C./sec. 2. A copper alloy ingot containing 0.1 to 0.45% by weight of oxygen and 0.05 to 5% by weight of silver, with the balance being copper and unavoidable impurities, is cast from 3 to 10% after casting.
A method for producing a high-strength and high-conductivity copper alloy wire, wherein the wire is formed by cooling at a cooling rate of 0 ° C./sec and then drawn.