WO2020209026A1 - Cu-(ni,co)-si alloy wire, insulated wire, method for producing cu-(ni,co)-si alloy wire, and method for producing insulated wire - Google Patents

Abstract

Provided is a Cu-(Ni,Co)-Si alloy wire that has flexibility (Vickers hardness of 150-200 HV) suitable for crimping connector terminals, in addition to electrical conductivity, strength, and elongation. Said Cu-(Ni,Co)-Si alloy wire contains 1.6-2.1 at% of Ni and/or Co; and 0.8-1.0 at% of Si, with the balance consisting of Cu and inevitable impurities, wherein the crystal grain size (average value) of the Cu matrix particles is 0.8-2.6 μm.

Description

Cu- (Ni, Co) -Si alloy wire, insulated wire, Cu- (Ni, Co) -Si alloy wire manufacturing method and insulated wire manufacturing method

The present invention relates to a method for manufacturing a Cu- (Ni, Co) -Si alloy wire, an insulated wire, a Cu- (Ni, Co) -Si alloy wire, and a method for manufacturing an insulated wire.

In next-generation vehicles such as quick charging of mobile devices and plug-in hybrid vehicles and electric vehicles, high-voltage and large-current circuits are required, and a large current tends to flow through the connector. Therefore, the connector material is required to have "high conductivity" in order to suppress energy loss when energized with a large current and deterioration of connection reliability due to stress relaxation progress due to heat generation. On the other hand, connectors for electronic devices and automobile parts are becoming smaller, lighter, and more precise, and Cu alloys, which are materials for connectors, are required to have "high strength" and "excellent elongation". In recent years, Cu- (Ni, Co) -Si based alloys have been attracting attention as Cu alloys satisfying these required characteristics.

Patent Document 1 discloses a Cu—Co—Si based alloy and a method for producing the same.
According to the technique of Patent Document 1, fine second-phase particles having a particle size of 50 nm or less are divided into second-phase particles having a particle size of 5-10 nm and second-phase particles having a particle size of 10-50 nm. The number density and ratio of these particles are controlled to improve the settling resistance while maintaining high conductivity and strength.

Patent Document 2 discloses a technique in which a Cu- (Ni, Co) -Si alloy is applied to a conductor wire rod for an electronic device.
According to the technique of Patent Document 2, the addition amount ratio of (Ni, Co) and Si is controlled, and the cold working ratio before and after the aging heat treatment is adjusted to improve the conductivity and strength. In particular, in paragraphs 0016-0018 of Patent Document 2 and Example 2, if the conductivity is 40% IACS or more, the tensile strength is 400 MPa or more, and the elongation is 5% or more, wiring of an automobile (wire harness for automobiles), a robot, etc. It mentions that it can be used suitably for the application, and the application is required to meet these standards.

Japanese Patent No. 4672804 Japanese Patent No. 5006405

However, although it is mentioned that both the techniques of Patent Documents 1 and 2 can be applied to wiring applications such as electronic parts, automobiles, and robots by using Cu- (Ni, Co) -Si alloy as a wire rod. It is not mentioned whether or not the connector terminals can be attached with a certain degree of flexibility when they are actually crimped, and it is unclear whether or not they are truly suitable for the wiring application. That is, when the connector terminals are crimped, the metal structure of the Cu- (Ni, Co) -Si alloy wire is partially stretched (strained) and the strength is increased, but the elongation is considered to decrease accordingly. Therefore, a certain degree of flexibility that can withstand the crimping is required, and for example, the Vickers hardness is required to be 150 HV or more and 200 HV or less.
Therefore, a main object of the present invention is Cu- having the same conductivity, strength and elongation as the techniques of Patent Documents 1 and 2 and flexibility (Vickers hardness of 150 HV or more and 200 HV or less) suitable for crimping of connector terminals. The purpose of the present invention is to provide (Ni, Co) -Si alloy wire rods.

According to the present invention, in order to solve the above problems
Cu- (Ni, Co)-containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic%, Si in an amount of 0.8 to 1.0 atomic%, and the balance consisting of Cu and unavoidable impurities. Si-based alloy wire
Provided is a Cu- (Ni, Co) -Si based alloy wire rod characterized in that the crystal grain size (average value) of Cu matrix particles is 0.8 to 2.6 μm.

According to the present invention, there is provided a Cu- (Ni, Co) -Si alloy wire having flexibility (Vickers hardness of 150 HV or more and 200 HV or less) suitable for crimping of a connector terminal in addition to conductivity, strength and elongation. (See Examples 1 and 2 below).

It is sectional drawing which shows the schematic structure of the insulated wire. It is a flowchart which shows the manufacturing method of the insulated wire over time. FE-SEM images (10,000 times) of sample 4 (left side) and sample 20 (right side). It is an optical microscope image (100 times) of a sample 20.

Hereinafter, a Cu- (Ni, Co) -Si alloy wire rod and an insulated wire containing the Cu- (Ni, Co) -Si alloy wire according to a preferred embodiment of the present invention will be described, and then a method for manufacturing the insulated wire (Cu- (Ni, Co) -Si. A method for manufacturing a system alloy wire rod is included.) Will be described. In the present specification, the lower limit value and the upper limit value are included in the numerical range with respect to the description of “～” indicating the numerical range.

(1) Cu- (Ni, Co) -Si-based alloy wire The Cu- (Ni, Co) -Si-based alloy wire is an alloy wire having Cu as a matrix, and at least one of Ni or Co is 1.6. It contains ~ 2.1 atomic% (preferably 1.7-2.0 atomic%) and contains 0.8-1.0 atomic% of Si, and has a composition in which the balance is Cu and unavoidable impurities. There is.
"At least one of Ni or Co" means either one of Ni or Co, or both Ni and Co.
In the Cu- (Ni, Co) -Si alloy wire, a fine second metal mainly composed of (Ni, Co) and Si intermetallic compounds is subjected to appropriate heat treatment (including aging annealing). Phase particles are precipitated, and the second phase particles are present as precipitates.
"Phase 2 particles" mainly means (Ni, Co) ₂ Si, which are the crystallization generated in the solidification process of the melting and casting process described later, the precipitates generated in the subsequent cooling process, and the aging annealing process. It refers to a precipitate generated in the process, and the second phase particles also include second phase particles containing unavoidable impurities.

In the Cu- (Ni, Co) -Si alloy wire, the crystal grain size (mean value) of the Cu matrix particles is 0.8 to 2.6 μm, preferably 1.5 to 1.9 μm.

The "crystal particle size" is a value based on JIS-H0501 (copper product crystal particle size test method).
The method for displaying the crystal grain size and the method for cutting are as follows.
How to display the crystal grain size;
The crystal grain size is indicated in mm. For example, it is expressed as 0.025 mm.
The following method is used to round the calculated or observed crystal grain size.
In the case of 0.010 mm or less, the value closest to an integral multiple of 0.001 mm is adopted.
If it exceeds 0.010 mm and is 0.060 mm or less, the value closest to an integral multiple of 0.005 mm is adopted.
If it exceeds 0.060 mm, the value closest to an integral multiple of 0.010 mm is adopted.
Cutting method;
The crystal grain size is indicated by counting the number of crystal grains that are completely cut by a line segment of a known length on a microscope image or a photograph, and displaying the average value (mm) of the cutting length. If necessary, measure along three axes parallel and perpendicular to the machining direction. The value measured by the cutting method may be smaller than the value measured by the quadrature method.

The above Cu- (Ni, Co) -Si alloy wire has flexibility with a Vickers hardness of 150 HV or more and 200 HV or less in accordance with JIS C 2244, and wiring for automobiles (wire harnesses for automobiles) and robots. Suitable for applications. The applications of Cu- (Ni, Co) -Si alloy wire rods are not limited to these applications, but can also be applied to wiring applications for electronic components, and can be applied to all applications including electrical connection.

(2) Insulated Wire FIG. 1 is a cross-sectional view showing a schematic configuration of an insulated wire.
As shown in FIG. 1, the insulated wire 1 has a conductor portion 10 and a covering portion 20.
The conductor portion 10 is formed by twisting a plurality of wire rods 12. The conductor portion 10 may be composed of one wire rod 12 (single wire). The wire rod 12 is composed of the above Cu— (Ni, Co) —Si alloy wire rod.
The coating portion 20 is a so-called sheath (coating) that insulates and coats the conductor portion 10, and is configured by extruding and coating a polyvinyl chloride resin (PVC: Poly Vinyl Chloride). The covering portion 20 is not limited to PVC and may be made of a known insulator such as cross-linked polyethylene.

(3) Manufacturing Method of Insulated Wire FIG. 2 is a flowchart showing a manufacturing method of the insulated wire over time.
As shown in FIG. 2, in the method for manufacturing an insulated wire, basically, each of the melting / casting process S1, the wire drawing process S2, the aging annealing process S3, the stranded wire processing process S4, and the insulation coating process S5 is performed in this order. Is done.

In the melting / casting step S1, the raw material is melted at 1100-1300 ° C., containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic% and Si in an amount of 0.8 to 1.0 atomic%. A composition (molten metal) in which the balance is composed of Cu and unavoidable impurities is prepared.
The "raw material" contains at least one of Ni or Co in an amount of 1.6 to 2.1 atomic% (preferably 1.7 to 2.0 atomic%) and Si in an amount of 0.8 to 1. The composition may contain 0 atomic% and the balance may be composed of Cu and unavoidable impurities, and may be a simple substance in which (Ni, Co), Si and Cu are separately present at the stage before dissolution. It may be a compound composed of two or more metal atoms of Ni, Co), Si and Cu, or it may be an integral substance of (Ni, Co), Si and Cu.
Then, the melt (raw material after melting, molten metal) is poured into a mold and cooled to room temperature within 5 minutes to 1 hour, preferably within 5 to 30 minutes, and a bar having a constant diameter is cast.

In the wire drawing process S2, the bar is drawn at a constant surface reduction rate to produce a wire having a constant diameter.
In the aging annealing step S3, the wire rod is heated at 300 to 600 ° C. for 0.5 to 4 hours for aging annealing. In the aging annealing step S3, fine second-phase particles mainly composed of (Ni, Co) and Si intermetallic compounds are precipitated, and the distortion of the metal structure generated in the wire drawing step S2 is removed.
A Cu- (Ni, Co) -Si alloy wire can be produced by the processes from the melting / casting step S1 to the aging annealing step S3.

In the stranded wire processing step S4, a plurality of wire rods after aging annealing are twisted and compressed to manufacture a stranded wire conductor. The process of the stranded wire processing step S4 may be performed after the wire drawing process step S2 and before the aging annealing step S3 (between the wire drawing process S2 and the aging annealing step S3).
In the insulation coating step S5, PVC is extruded and coated on the stranded conductor, and the stranded conductor is insulated and coated with PVC. An insulated wire can be manufactured by the processes from the melting / casting step S1 to the insulating coating step S5.

(1) Preparation of wire rod sample (1.1) Sample 1-8
The raw materials were heated at 1300 ° C. and melted to prepare a composition (molten metal) having the composition ratios shown in Table 1. Then, the melt (raw material after melting, molten metal) was poured into a mold and cooled to room temperature within 10 minutes, and a bar having a diameter of 12.0 mm was cast.
Then, a rod having a diameter of 12.0 mm was drawn with a surface reduction rate of 10 to 20% to produce a wire having a diameter of 1.1 mm.
Then, a wire rod having a diameter of 1.1 mm was heated at 525 ° C. for 5 hours and annealed by aging.

(1.2) Sample 20
A bar having a diameter of 12.0 mm was produced in the same manner as in Sample 4.
Then, a rod having a diameter of 12.0 mm was heated (dissolved) at 950 ° C. for 1 hour, cooled with water, and heated at 525 ° C. for 1 hour for aging annealing.

(2) Characteristic evaluation of wire rod sample (2.1) Measurement of crystal grain size The crystal grain size was calculated by observing the structure by a method according to JIS-H0501.
FE-SEM (field emission scanning electron microscope S-4500 manufactured by Hitachi High-Technologies Corporation) was used for microstructure observation. Samples 1-8 and 20 were observed at a magnification of 10,000 times, and sample 20 was observed at a magnification of 100 times, and the crystal grain size (mean value) was calculated.
The calculation results are shown in Table 1. As a representative example, FE-SEM images (10,000 times) of samples 4 and 20 are shown in FIG. 3, and optical microscope images (100 times) of samples 20 are shown in FIG. 4, respectively.

(2.2) Measurement of Vickers hardness The Vickers hardness was measured by a method according to JIS C 2244.
A Vickers hardness measuring device (AMT-X7AFS) manufactured by Matsuzawa Co., Ltd. was used as the measuring device. The measurement conditions were as follows.
Load: 100gf
Retention time: 15 seconds Table 1 shows the measurement results.

(3) Summary As shown in Table 1, in Samples 1-3, the amount of added elements of Co and Si was large, and even if appropriate heat treatment was performed (even by aging annealing), the Vickers hardness was large. On the contrary, in Samples 7-8, the Vickers hardness was small because the amount of added elements of Co and Si was small.
As shown on the left side of Table 1 and FIG. 3, in Sample 4-6, the crystal grain size of the Cu parent phase particles is remarkably smaller than that of Sample 20, and the second phase particles are more distributed at the grain boundaries (the left side of FIG. 3 is the sample). The metallographic structure of sample 4 is shown as a representative example of 4-6). On the other hand, as shown in Table 1, the right side of FIG. 3 and FIG. 4, in the sample 20, the crystal grain size of the Cu matrix particles is remarkably larger than that of the sample 4-6, and the second phase particles are largely distributed in the crystal grains.
From the above, the correlation between the composition ratio of Cu, Co, and Si, the metallographic state, and the Vickers hardness is whether the composition ratio of Co and Si is within an appropriate range, or the second phase particles are the crystal grains of the Cu parent phase. It is considered that this is due to whether it is distributed abundantly in the boundary or in the crystal grains, and contains 1.6 to 2.1 atomic% of Co, 0.8 to 1.0 atomic% of Si, and Cu. It was found that the crystal grain size (average value) of the matrix phase of 0.8 to 2.6 μm is useful for flexibility.

A stranded conductor was produced from Samples 1-8 and 20 of Example 1 and its conductivity, tensile strength and elongation were measured.

(1) Preparation of Twisted Conductor Sample As a stranded conductor sample, seven samples 1-8 and 20 were twisted and compressed to produce a circular compressed stranded conductor having a cross-sectional area of 0.13 mm ² .

(2) Characteristic evaluation of stranded conductor samples (2.1) Measurement of conductivity Using the DC four-terminal method, conductivity is measured for each of the five samples in a room controlled at 20 ° C (± 1 ° C). The average value (% IACS) was calculated. The distance between the voltage terminals was set to 300 mm. The calculation results are shown in Table 2.

(2.2) Tensile strength Tensile strength was measured for each of the five samples according to JIS Z 2241, and the average value (MPa) was calculated. The calculation results are shown in Table 2.

(2.3) Elongation At the time of measuring the above (2.2) tensile strength, the elongation was measured at the same time, and the average value (%) was calculated. The calculation results are shown in Table 2.

(3) Summary As shown in Table 2, in Samples 1-3, the amounts of added elements of Co and Si are large, and the second phase particles composed of them are present at the grain boundaries at the time of casting the base material, and are aged. During annealing, the second phase particles grew into crystals, and a large amount of them were precipitated at the grain boundaries of the Cu parent phase particles, so that the grain boundary strength became weak and the elongation could not be measured or was low. In Samples 7 and 8, the amount of added elements of Co and Si was small enough to contribute to the improvement of strength, and it was considered that the required amount of the second phase particles was not precipitated in the Cu matrix, and the tensile strength was small.
On the other hand, in Sample 4-6, the conductivity, tensile strength and elongation satisfy certain standard values required for wiring applications such as automobiles (wire harnesses for automobiles) and robots described in Patent Document 2. It was confirmed that the insulated wire can be suitably used for this purpose.

The present invention relates to Cu- (Ni, Co) -Si alloy wire rods, and is suitably used for wiring applications such as automobiles (wire harnesses for automobiles) and robots.

1 Insulated wire 10 Conductor part 12 Wire rod 20 Coating part S1 Melting / casting process S2 Wire drawing process S3 Aging annealing process S4 Twisted wire processing process S5 Insulation coating process

Claims (6)

Cu- (Ni, Co)-containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic%, Si in an amount of 0.8 to 1.0 atomic%, and the balance consisting of Cu and unavoidable impurities. Si-based alloy wire
A Cu- (Ni, Co) -Si alloy wire rod having a crystal grain size (mean value) of 0.8 to 2.6 μm of Cu matrix particles. In the Cu- (Ni, Co) -Si alloy wire rod according to claim 1,
A Cu- (Ni, Co) -Si alloy wire rod having a crystal grain size (mean value) of 1.5 to 1.9 μm of Cu matrix particles. Cu- (Ni, Co)-containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic%, Si in an amount of 0.8 to 1.0 atomic%, and the balance consisting of Cu and unavoidable impurities. A conductor portion composed of the Cu- (Ni, Co) -Si alloy wire having a crystal grain size (average value) of 0.8 to 2.6 μm of the Cu matrix particles, which is a Si alloy wire,
An insulated wire including a covering portion that insulates and coats the conductor portion. In the insulated wire according to claim 3,
An insulated wire having a crystal grain size (mean value) of Cu matrix particles of 1.5 to 1.9 μm. The raw material is melted at 1100-1300 ° C., containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic%, Si in an amount of 0.8 to 1.0 atomic%, and the balance being Cu and unavoidable impurities. The process of preparing a composition consisting of, cooling the melt to room temperature, and casting a bar,
The process of drawing the rod to manufacture the wire and
A step of heating the wire at 300 to 600 ° C. for 0.5 to 4 hours, and
A method for producing a Cu- (Ni, Co) -Si alloy wire rod, which comprises the above. The raw material is melted at 1100-1300 ° C., containing at least one of Ni or Co in an amount of 1.6 to 2.1 atomic%, Si in an amount of 0.8 to 1.0 atomic%, and the balance being Cu and unavoidable impurities. The process of preparing a composition consisting of, cooling the melt to room temperature, and casting a bar,
The process of drawing the rod to manufacture the wire and
A step of heating the wire at 300 to 600 ° C. for 0.5 to 4 hours, and
A process of manufacturing a stranded conductor by twisting a plurality of the above-mentioned wires after heating,
The process of coating the stranded conductor with an insulator and
A method of manufacturing an insulated wire, which comprises.

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