AU2017282513B2

AU2017282513B2 - Copper alloy, copper alloy ingot, copper alloy solution forming material, copper alloy trolley wire and method for producing copper alloy trolley wire

Info

Publication number: AU2017282513B2
Application number: AU2017282513A
Authority: AU
Inventors: Yuusuke Enami; Hitoshi Nakamoto; Takuya Ohara; Keiichiro Oishi; Toshio Sakamoto; Atsushi Sugahara; Chikara Yamashita
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2016-06-23
Filing date: 2017-06-23
Publication date: 2022-04-07
Anticipated expiration: 2037-06-23
Also published as: AU2017282513A1; MY188578A; WO2017222041A1

Abstract

This copper alloy is characterized by having a composition that contains from 0.05 mass% to 0.70 mass% (inclusive) of Co, from 0.02 mass% to 0.20 mass% (inclusive) of P, from 0.005 mass% to 0.70 mass% (inclusive) of Sn, and one or more elements selected from among B, Cr and Zr, with the balance made up of Cu and unavoidable impurities; and this copper alloy is also characterized in that if X (mass ppm) is the content of B, Y (mass ppm) is the content of Cr and Z (mass ppm) is the content of Zr, X, Y and Z satisfy formula (1) 1 ≤ (X/5) + (Y/50) + (Z/100) and formula (2) X + Y + Z ≤ 1,000.

Description

DESCRIPTION

Title of Invention

COPPER ALLOY, COPPER ALLOY INGOT, SOLID SOLUTION MATERIAL OF COPPER ALLOY, AND COPPER ALLOY TROLLEY WIRE, METHOD OF MANUFACTURING COPPER ALLOY TROLLEY WIRE

Technical Field

[0001]

The present invention relates to a precipitation hardening-type copper alloy

containing Co, P, and Sn which is used for, for example, a wire in a vehicle or a device, a

trolley wire, a wire for a robot, a wire for an aircraft, and the like, a copper alloy ingot, a

solid solution material of copper alloy, and a copper alloy trolley wire, a method of

manufacturing a copper alloy trolley wire.

Priority is claimed on Japanese Patent Application No. 2016-124661, filed June

23, 2016, and Japanese Patent Application No. 2017-115427, filed June 12, 2017, the

contents of which are incorporated herein by reference.

Background Art

[0002]

In the related art, for example, as described in Patent Document 1 and 2, as an

electrical wire for wires in a vehicle or a device, an electrical wire obtained by coating an

electrical wire conductor, which is formed by twisting a plurality of copper wires together,

with an insulating coat is provided. In addition, for efficient wiring or the like, a wire

harness obtained by bundling a plurality of the above-described electrical wires is provided.

In recent years, from the viewpoint of environmental protection, there has been a

strong demand for a decrease in the weight of a vehicle frame in order to reduce the

amount of carbon dioxide discharged from a vehicle. Meanwhile, as not only the

computerization of a vehicle but also the development of a hybrid vehicle or an electric

vehicle are making progress, and the number of electrical components used in a vehicle is

increasing at an accelerating rate. Therefore, the amount of wire harnesses used to

connect these components is estimated to further increase in the future, and there is a

demand for a decrease in the weight of the wire harness.

Here, as means for decreasing the weight of the wire harness, an attempt has

been made to decrease the diameters of electrical wires and copper wires. In addition,

the decrease in the diameters of an electrical wire conductor and a copper wire decreases

not only the weight but also the size of the wire harness, and thus there is another

advantage that the wiring space can be effectively used.

[0003]

In addition, a trolley wire which is used for an electric railroad vehicle or the

like is constituted to slide into contact with a power collection device such as a

pantograph and feed power to an electric railroad vehicle or the like. In order to obtain

favorable power collection performance such as small line separation from the

pantograph, the fluctuation propagation speed of the trolley wire needs to be sufficiently

faster than the travelling speed. The fluctuation propagation speed of the trolley wire is

proportional to the square root of a tensile force being exerted, and thus, in order to

improve the fluctuation propagation speed, a high-strength trolley wire is required. In

addition, the trolley wire is demanded to be excellent in terms of electrical conductivity,

wear resistance, and fatigue characteristics.

[0004]

In recent years, the travelling speed of electric railroad vehicles has been

increasing; however, when, in a high-speed railway such as Shinkansen, the travelling

speed of an electric railroad vehicle becomes faster than the propagation speed of a wave

generated in an overhead wire such as a trolley wire, the contact between the power

collection device such as the pantograph and the trolley wire becomes unstable and thus

there is a concern that it may become impossible to stably feed power.

Here, since it becomes possible to increase the propagation speed of a wave in

the trolley wire by increasing the overhead wire tension of the trolley wire, there is a

demand for a trolley wire having a higher strength than before.

[0005]

As a copper alloy wire made of a copper alloy having a high strength and a high

electrical conductivity which satisfy the above-described demanded characteristics, for

example, as disclosed in Patent Document 1 to 3, copper alloy wires containing Co, P,

and Sn have been proposed. In these copper alloy wires, it becomes possible to improve

the strength while ensuring the electrical conductivity by precipitating a complex of Co

and P in the matrix of copper.

In addition, Patent Document 4 proposes a PHC trolley wire developed for

high-speed travelling. This PHC trolley wire is constituted of a copper alloy containing

Cr, Zr, and Sn and is excellent in terms of strength and electrical conductivity.

[0006]

Meanwhile, in a case in which the above-described copper alloy wire containing

Co, P, and Sn described in Patent Document 1 to 3 and the copper alloy trolley wire

described in Patent Document 4 are manufactured, a method is carried out in which an

ingot having a large sectional area called a billet is produced, the billet is hot-extruded through reheating, and then a wire drawing process or the like is further carried out.

However, in a case in which a copper alloy is manufactured by carrying out hot extrusion

after the production of an ingot having a large sectional area, the length of the copper

alloy to be obtained is limited by the size of the ingot, and it has not been possible to

obtain a long copper alloy wire (copper alloy trolley wire). In addition, there has been

another problem of poor production efficiency.

[0007]

Therefore, for example, a method has been proposed in which a copper alloy

wire is manufactured using a continuous casting and rolling method in which a

belt-wheel type continuous casting apparatus or the like is used. In this case, since

casting and rolling are continuously carried out, the production efficiency is high and it

becomes possible to obtain a long copper alloy wire.

In addition, another method has also been proposed in which a continuous cast

wire rod is manufactured using an upward continuous caster, a transverse continuous

caster, and a hot top continuous caster, and the continuous cast wire rod is directly

cold-worked without being reheated, thereby manufacturing a copper alloy wire.

[0008]

However, there has been a tendency in the copper alloy wire manufactured using

the continuous casting and rolling method in which a belt-wheel type continuous casting

apparatus or the like is used and the copper alloy wire manufactured by directly cold

working a continuous cast wire rod without reheating the continuous cast wire for the

strength to become lower compared with the copper alloy wire manufactured using the

manufacturing method including the hot extrusion step of hot-extruding a billet.

Therefore, in order to ensure the strength, it is necessary to manufacture a copper alloy

wire using the manufacturing method including the hot extrusion step, and it has not been possible to efficiently produce high-strength copper.

[0009]

Here, as a result of intensive studies, the present inventors clarified that, in a

copper alloy wire manufactured using a continuous casting and rolling method, Co and P

more significantly segregate than a copper alloy wire manufactured using a

manufacturing method including a hot extrusion step. Therefore, Patent Document 5

proposes a technique for suppressing the segregation of Co and P and improving the

tensile strength and the electrical conductivity by specifying the ratio between Co and P.

In addition, Patent Document 6 discloses that a copper alloy trolley wire which is

excellent in terms of strength, heat resistance, electrical conductivity, and elongation is

manufactured using a continuous casting and rolling method.

Citation List

Patent Literature

[0010]

[Patent Document 1] Japanese Unexamined Patent Application, First

Publication No. 2010-212164

[Patent Document 2] Republished Japanese Translation No. 2009/107586 of

the PCT International Publication for Patent Applications

[Patent Document 3] Republished Japanese Translation No. 2009/119222 of

the PCT International Publication for Patent Applications

[Patent Document 4] Japanese Unexamined Patent Application, First

Publication No. H08-157985

[Patent Document 5] Japanese Patent No. 5773015

[Patent Document 6] Japanese Patent No. 6027807

Any discussion of the prior art throughout the specification should in no way be

considered as an admission that such prior art is widely known or forms part of common

general knowledge in the field.

Summary of Invention

Technical Problem

[0011]

However, in Patent Document 5, the segregation of Co and P is suppressed by

specifying the ratio between Co and P which are the main components; however, in order

to suppress the segregation, it is also effective to carry out a solid solution treatment on a

continuous-cast wire rod manufactured using a continuous casting and rolling method or

a continuous casting method. In addition, in a copper alloy ingot such as a billet, it is

also preferable to carry out a sufficient solid solution treatment in order to suppress the

segregation of Co and P.

However, in a case in which a solid solution treatment is carried out on a

continuous-cast wire rod or a copper alloy ingot made of the above-described copper

alloy containing Co, P, and Sn, there has been a problem in that crystal grain diameters

coarsen and the workability significantly degrades after the solid solution treatment. In

addition, there is another problem in that the continuous-cast wire rod or the copper alloy

ingot embrittles at a high temperature and thus the elongation degrades and breaking is

likely to be generated.

[0012]

In addition, in a trolley wire being used for an electric railroad vehicle or the like,

the speed of the electric railroad vehicle has been further increased and become faster

than in the related art, and excellent wear characteristics and excellent fatigue characteristics are demanded. Here, in the copper alloy trolley wire disclosed in Patent

Document 6, there has been a problem in that the crystal grain diameters coarsen during

the solid solution treatment and the wear characteristics and the fatigue characteristics do

not sufficiently improve as described above.

[0013]

The present invention has been made in consideration of the above-described

circumstances, and an object of the present invention is to provide a copper alloy

containing Co, P, and Sn which is capable of suppressing the coarsening of the crystal

grain diameters even in a case in which a solid solution treatment is carried out, is

excellent in terms of workability and high-temperature elongation, and is excellent in

terms of strength and electrical conductivity, a copper alloy ingot, a solid solution

material of copper alloy, and a copper alloy trolley wire which is excellent in terms of

wear characteristics and fatigue characteristics and a method of manufacturing a copper

alloy trolley wire.

It is an object of the present invention to overcome or ameliorate at least one of

the disadvantages of the prior art, or to provide a useful alternative.

Solution to Problem

[0014]

In order to achieve the above-described object, a copper alloy according to an

aspect of the present invention (hereinafter, referred to as "the copper alloy of the present

invention") having a composition includes: 0.05 mass% or more and 0.70 mass% or less

of Co, 0.02 mass% or more and 0.20 mass% or less of P, 0.005 mass% or more and 0.70

mass% or less of Sn, one or more of B, Cr, and Zr; and a Cu balance containing

inevitable impurities, wherein X, Y, and Z satisfy the following Expressions (1) and (2);

Expression (1): 1 (X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z1,000, the amount of B is represented by X (massppm),

the amount of Cr is represented by Y (massppm), and the amount of Zr is represented by

Z (massppm), and

wherein the amount of B is in a range of 5 massppm or more and 1,000

massppm or less.

[0015]

In the copper alloy having the above-described constitution, any one or more of

B, Cr, and Zr are included, and, when the amount of B is represented by X (massppm),

Z (massppm), Expression (1) is satisfied, and thus, even in a case in which the copper

alloy is heated and held at a high temperature, the coarsening of the crystal grain

diameters is suppressed due to the action of these elements, and the workability and the

high-temperature elongation are excellent. In addition, it becomes possible to carry out

a sufficient solid solution treatment, precipitates can be finely and uniformly dispersed by

the subsequent aging heat treatment, and it is possible to improve the strength and the

electrical conductivity.

Meanwhile, the contents of B, Cr, and Zr satisfy Expression (2), and thus it is

possible to suppress the degradation of the castability or the generation of casting

breaking due to the elements of B, Cr, and Zr.

[0016]

Here, in the copper alloy of the present invention, X and Y preferably satisfy the

following Expressions (3) and (4);

Expression (3): 1 (2X/5)+(2Y/50),

Expression (4): Y<400.

In this case, Expression (3) is satisfied, and thus, even in a case in which the

copper alloy is heated and held at a high temperature, the coarsening of the crystal grain

diameters can be further suppressed. In addition, Expression (4) is satisfied, and thus it

is possible to further suppress the degradation of the castability or the generation of

casting breaking.

[0017]

In addition, in the copper alloy of the present invention, the amount of B may be

in a range of 5 massppm or more and 1,000 massppm or less.

Even in a case in which, out of B, Cr, and Zr, only B is intentionally added to the

copper alloy, the amount of B is set to be in a range of 5 massppm or more and 1,000

massppm or less, and Expression (1) and Expression (2) and, furthermore, Expression (3)

and Expression (4) are satisfied, and thus there is no case in which the castability

degrades or casting breaking is generated, and it is possible to suppress the coarsening of

crystal grains when the copper alloy is heated and held at a high temperature.

[0018]

In addition, the copper alloy of the present invention may further include either

or both of: 0.01 mass% or more and 0.15 mass% or less of Ni and 0.005 mass% or more

and 0.07 mass% or less of Fe.

In this case, Ni and Fe are included in the above-described ranges, and thus it is

possible to miniaturize precipitates containing Co and P without significantly degrading

the electrical conductivity, and furthermore, the strength can be improved.

[0019]

In addition, the copper alloy of the present invention may further include any

one or more of: 0.002 mass% or more and 0.50 mass% or less of Zn, 0.002 mass% or

more and 0.25 mass% or less of Mg, and 0.002 mass% or more and 0.25 mass% or less of Ag.

In this case, Zn, Mg, and Ag are included in the above-described ranges, and

thus it is possible to fix S in the copper alloy without significantly degrading the

castability and suppress S forming a solid solution in the matrix of copper, and the

electrical conductivity can be improved.

[0020]

A copper alloy ingot of another aspect of the present invention (hereinafter,

referred to as the copper alloy ingot of the present invention) is a copper alloy ingot

having the composition of the above-described copper alloy, in which the average crystal

grain size after cold rolling of a working ratio of 50% and a heat treatment at 950°C for

one hour is 400 pm or less.

In the copper alloy ingot having this constitution, the average crystal grain size

after cold rolling of a working ratio of 50% and a heat treatment at 950°C for one hour is

set to 400 pm or less, and thus the crystal grains coarsening during the holding of the

copper alloy ingot at a high temperature is suppressed, and it is possible to obtain a

copper alloy member which is excellent in terms of strength and electrical conductivity

by carrying out a sufficient solid solution treatment.

[0021]

In addition, in the copper alloy ingot of the present invention, an electrical

conductivity after the heat treatment at 950°C for one hour is preferably 45%IACS or

less.

In this case, a heat treatment is carried out at 950°C for one hour, and thus the

electrical conductivity is decreased to 45%IACS or less, and the copper alloy ingot is

sufficiently solutionized.

[0022]

A solid solution material of a copper alloy of another aspect of the present

invention (hereinafter, referred to as "the solid solution material of a copper alloy of the

present invention") is a solid solution material of a copper material having the

composition of the above-described copper alloy, in which an electrical conductivity is

45%IACS or less.

In the solid solution material of copper alloy having this constitution, the

electrical conductivity is set to 45%IACS or less, and the solid solution material of

copper alloy is sufficiently solutionized. Therefore, it is possible to finely and

uniformly disperse precipitates by the subsequent aging heat treatment, and a copper

alloy member that is excellent in terms of strength and electrical conductivity can be

obtained.

[0023]

A copper alloy trolley wire of another aspect of the present invention

(hereinafter, referred to as "the copper alloy trolley wire of the present invention") having

a composition includes 0.12 mass% or more and 0.40 mass% or less of Co, 0.04 mass%

or more and 0.16 mass% or less of P, 0.01 mass% or more and 0.50 mass% or less of Sn,

one or more of B, Cr, and Zr; and a Cu balance containing inevitable impurities,

wherein X, Y, and Z satisfy the following Expressions (1) and (2);

Expression (1): 1 (X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z1,000, in case where the amount of B is represented by

X (massppm), the amount of Cr is represented by Y (massppm), and the amount of Zr is

represented by Z (massppm),_and

wherein the amount of B is in a range of 5 massppm or more and 1,000

massppm or less.

[0024]

In the copper alloy trolley wire having the above-described constitution, Co;

0.12 mass% or more and 0.40 mass% or less, P; 0.04 mass% or more and 0.16 mass% or

less, and Sn; 0.01 mass% or more and 0.50 mass% or less are included, and thus it is

possible to provide a strength and an electrical conductivity necessary for a trolley wire.

In addition, any one or more of B, Cr, and Zr are included, and, when the

amount of B is represented by X (massppm), the amount of Cr is represented by Y

(massppm), and the amount of Zr is represented by Z (massppm), Expression (1) is

satisfied, and thus, even in a case in which the copper alloy trolley wire is heated and

held at a high temperature, the coarsening of the crystal grain diameters is suppressed due

to the action of these elements, and the copper alloy trolley wire becomes excellent in

terms of wear characteristics and fatigue characteristics. In addition, it becomes

possible to carry out a sufficient solid solution treatment, precipitates can be finely and

uniformly dispersed by the subsequent aging heat treatment, and it is possible to improve

the strength and the electrical conductivity.

Meanwhile, the amounts of B, Cr, and Zr satisfy Expression (2), and thus it is

breaking due to the elements of B, Cr, and Zr.

[0025]

Here, in the copper alloy trolley wire of the present invention, X and Y satisfy

the following Expressions (3) and (4);

Expression (3): 1<(2X/5)+(2Y/50),

Expression (4): Y<400.

copper alloy trolley wire is heated and held at a high temperature, the coarsening of the crystal grain diameters can be further suppressed, and it is possible to further improve the wear characteristics and the fatigue characteristics. In addition, Expression (4) is satisfied, and thus it is possible to further suppress the degradation of the castability or the generation of casting breaking.

[0026]

In addition, in the copper alloy trolley wire of the present invention, the amount

of B may be in a range of 5 massppm or more and 1,000 massppm or less.

degrades or casting breaking is generated, it is possible to suppress the coarsening of

crystal grains when the copper alloy is heated and held at a high temperature, and the

wear characteristics and the fatigue characteristics can be improved..

[0027]

A method of manufacturing a copper alloy trolley wire according to another

aspect of the present invention (hereinafter, referred to as "the method of manufacturing a

copper alloy trolley wire of the present invention") is a method of manufacturing the

above-described copper alloy trolley wire including a continuous casting and rolling step

of continuously producing a copper wire rod; a solid solution treatment step of carrying

out a solid solution treatment on the copper wire obtained; a primary cold working step

of producing a copper wire material by carrying out cold working on a solid solution

material after the solid solution treatment step; an aging heat treatment step of carrying

out an aging heat treatment on the copper wire material; and a secondary cold working

step of carrying out cold working on an aging heat-treated material after the aging heat treatment step, in which, in the solid solution treatment step, a holding temperature is set to be in a range of 900°C or more and 1,000°C or less, and a holding time at the holding temperature is set to be in a range of 30 minutes or more and 600 minutes or less, and, in the aging heat treatment step, a heat treatment temperature is set to be in a range of

300°C or more and 600°C or less, and a holding time at the heat treatment temperature is

set to be in a range of 60 minutes or more and 1,500 minutes or less.

[0028]

According to the method of manufacturing a copper alloy trolley wire having

this constitution, the continuous casting and rolling step of continuously producing a

copper wire rod and the solid solution treatment step of carrying out a solid solution

treatment on the obtained copper wire rod are included, and, in the solid solution

treatment step, the holding temperature is set to be in a range of 900°C to 1,000°C, and

the holding time at the holding temperature is set to be in a range of 30 minutes to 600

minutes, and thus it is possible to sufficiently solve the segregation of Co and P in the

copper wire rod manufactured using a continuous casting and rolling method.

In addition, in the aging heat treatment step, the heat treatment temperature is set

to be in a range of 300°C to 600°C, and the holding time at the heat treatment

temperature is set be in a range of 60 minutes to 1,500 minutes, and thus the aging

treatment can be reliably carried out, and it is possible to sufficiently precipitate the

precipitates of Co and P. Therefore, it becomes possible to manufacture a copper alloy

trolley wire that is excellent in terms of strength and electrical conductivity.

Advantageous Effects of Invention

[0029]

According to the present invention, it becomes possible to provide a copper

alloy containing Co, P, and Sn which is capable of suppressing the coarsening of the

crystal grain diameters even in a case in which a solid solution treatment is carried out, is

alloy trolley wire.

Brief Description of Drawings

[0030]

FIG. 1 is a flowchart showing a method of manufacturing a copper alloy member

in a first embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a continuous casting and rolling

facility used in the manufacturing method shown in FIG. 1.

FIG. 3 is a flowchart showing a method of manufacturing a copper alloy member

in a second embodiment of the present invention.

FIG. 4 is a flowchart showing a method of manufacturing a copper alloy trolley

wire in a third embodiment of the present invention.

FIG. 5A is an explanatory view of an H-shaped metal die being used to evaluate

casting breaking in an example.

FIG. 5B is an explanatory view of the H-shaped metal die being used to evaluate

casting breaking in the example.

FIG. 6 is a schematic explanatory view of a testing device being used to evaluate

fatigue characteristics in the example.

FIG. 7 is a schematic explanatory view of a testing device being used to evaluate

wear characteristics in the example.

FIG. 8 is a graph showing evaluation results of the fatigue characteristics

(fatigue service lives) of Invention Example 82, Comparative Example 71, and a related

art example.

FIG. 9 is a graph showing evaluation results of the wear characteristics of

Invention Example 82 and the related art example.

Description of Embodiments

[0031]

Hereinafter, an embodiment of the present invention will be described with

reference to the accompanying drawings.

[0032]

A copper alloy which is a first embodiment of the present invention has a

composition including 0.05 mass% or more and 0.70 mass% or less of Co, 0.02 mass%

or more and 0.20 mass% or less of P, 0.005 mass% or more and 0.70 mass% or less of Sn,

any one or more of B, Cr, and Zr, and furthermore, a Cu balance containing inevitable

impurities. The amount of B is represented by X (massppm). The amount of Cr is

represented by Y (massppm). The amount of Zr is represented by Z (massppm). X, Y,

and Z satisfy the following Expressions (1) and (2);

Expression (1): 1 (X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z<1,000.

[0033]

Furthermore, in the present embodiment, the contents of B, Cr, and Zr satisfy the

following Expressions (3) and (4);

Expression (3): 1<(2X/5)+(2Y/50),

Expression (4): Y<400.

[0034]

Meanwhile, the copper alloy may further include either or both of 0.01 mass%

or more and 0.15 mass% or less of Ni and 0.005 mass% or more and 0.07 mass% or less

of Fe.

In addition, the copper alloy may further include any one or more of 0.002

mass% or more and 0.50 mass% or less of Zn, 0.002 mass% or more and 0.25 mass% or

less of Mg, and 0.002 mass% or more and 0.25 mass% or less of Ag.

Hereinafter, the reasons for setting the contents of the respective elements in the

above-described ranges will be described.

[0035]

(Co)

Co is an element that forms, together with P, precipitates which disperse in the

matrix of copper.

Here, in a case in which the amount of Co is less than 0.05 mass%, the number

of precipitates is insufficient, and there is a concern that it may be impossible to

sufficiently improve the strength. On the other hand, in a case in which the amount of

Co exceeds 0.70 mass%, a number of elements not contributing to the improvement of

the strength are present, and there is a concern that a decrease in the electrical

conductivity and the like may be caused.

Therefore, in the present embodiment, the amount of Co is set to be in a range of

0.05 mass% or more and 0.70 mass% or less.

Meanwhile, in order to reliably ensure the number of precipitates, the lower

limit of the amount of Co is preferably set to 0.12 mass% or more and more preferably set to 0.25 mass% or more. On the other hand, in order to reliably suppress a decrease in the electrical conductivity, the upper limit of the amount of Co is preferably set to 0.40 mass% or less and more preferably set to 0.36 mass% or less.

[0036]

(P)

P is an element that forms, together with Co, precipitates which disperse in the

matrix of copper.

In a case in which the amount of P is less than 0.02 mass%, the number of

precipitates is insufficient, and there is a concern that it may be impossible to sufficiently

improve the strength. On the other hand, in a case in which the amount of P exceeds

0.20 mass%, there is a concern that a decrease in the electrical conductivity and the like

may be caused.

Therefore, in the present embodiment, the amount of P is set to be in a range of

0.02 mass% or more and 0.20 mass% or less.

Meanwhile, in order to reliably ensure the number of precipitates, the lower

limit of the amount of P is preferably set to 0.04 mass% or more and more preferably set

to 0.08 mass% or more. On the other hand, in order to reliably suppress a decrease in

the electrical conductivity, the upper limit of the amount of P is preferably set to 0.16

mass% or less and more preferably set to 0.14 mass% or less.

[0037]

(Sn)

Sn is an element having an action in which Sn forms a solid solution in the

matrix of copper so as to improve the strength. In addition, Sn also has an effect of

accelerating the precipitation of precipitates containing Co and P as the main components

and an action of improving heat resistance and corrosion resistance.

Here, in a case in which the amount of Sn is less than 0.005 mass%, there is a

concern that it may be impossible to exhibit the above-described action effect. On the

other hand, in a case in which the amount of Sn exceeds 0.70 mass%, there is a concern

that it may be impossible to ensure the electrical conductivity.

Based on what has been described above, in the present embodiment, the

amount of Sn is set to be in a range of 0.005 mass% or more and 0.70 mass% or less.

Meanwhile, in order to reliably exhibit the above-described action effect, the

lower limit of the amount of Sn is preferably set to 0.01 mass% or more and more

preferably set to 0.02 mass% or more. On the other hand, in order to reliably suppress a

decrease in the electrical conductivity, the upper limit of the amount of Sn is preferably

set to 0.50 mass% or less and more preferably set to 0.10 mass% or less.

[0038]

(B, Cr, and Zr)

These B, Cr, and Zr are elements having an action of suppressing the coarsening

of crystal grains when the copper alloy is held at a high temperature. Regarding the

contents of B, Cr, and Zr, when the amount of B is represented by X (massppm), the

amount of Cr is represented by Y (massppm), and the amount of Zr is represented by Z

(massppm), Expression (1) and Expression (2) are specified.

[0039]

In a case in which the contents of B, Cr, and Zr do not satisfy Expression (1):

1<(X/5)+(Y/50)+(Z/100), it is not possible to sufficiently suppress the coarsening of

crystal grains when the copper alloy is held at a high temperature, there is a concern that

the strength may decrease and the copper alloy may embrittle at a high temperature, and

there is another concern that the workability may degrade.

Meanwhile, in a case in which the contents of B, Cr, and Zr do not satisfy

Expression (2): X+Y+Z1,000, there is a concern that the castability or the electrical

conductivity may degrade or casting breaking may be generated.

Based on what has been described above, in the present embodiment, the

contents of B, Cr, and Zr need to satisfy Expression (1) and Expression (2).

Meanwhile, in order to further suppress the coarsening of the crystal grains

when the copper alloy is held at a high temperature, the contents of B, Cr, and Zr

preferably satisfy Expression (3): 1 (2X/5)+(2Y/50).

Furthermore, in order to further suppress the degradation of the castability or

casting breaking, the contents of B, Cr, and Zr preferably satisfy Expression (4): Y<400.

[0040]

(Ni and Fe)

Ni and Fe are elements having an action effect of miniaturizing the precipitates

made of the complex of Co and P.

Here, in a case in which the amount of Ni is less than 0.01 mass% or a case in

which the amount of Fe is less than 0.005 mass%, there is a concern that it may be

impossible to reliably exhibit the above-described action effect. On the other hand, in a

case in which the amount of Ni exceeds 0.15 mass% or a case in which the amount of Fe

exceeds 0.07 mass%, there is a concern that it may be impossible to ensure the electrical

conductivity.

Therefore, in a case in which Ni is contained, the amount of Ni is preferably set

in a range of 0.01 mass% or more and 0.15 mass% or less, and in a case in which Fe is

contained, the amount of Fe is preferably set in a range of 0.005 mass% or more and 0.07

mass% or less.

[0041]

(Zn, Mg, and Ag)

Elements such as Zn, Mg, and Ag are elements that form a compound with S

and have an action of improving the electrical conductivity by suppressing the formation

of a solid solution of S in the matrix of copper.

Here, in a case in which the contents of the elements of Zn, Mg, and Ag are

respectively less than the above-described lower limit values, there is a concern that it

may not be possible to sufficiently exhibit the action effect of suppressing the formation

of the solid solution of S in the matrix of copper. On the other hand, in a case in which

the contents of the elements of Zn, Mg, and Ag respectively exceed the above-described

upper limit values, there is a concern that it may become impossible to ensure the

electrical conductivity.

Therefore, in a case in which the elements of Zn, Mg, and Ag are contained, the

contents thereof are preferably set in the above-described ranges respectively.

[0042]

Next, a method of manufacturing a copper alloy member made of the

above-described copper alloy will be described. FIG. 1 shows a flowchart of a method

of manufacturing a copper alloy member which is the embodiment of the present

invention.

First, a copper wire rod 50 made of a copper alloy having the above-described

composition is continuously produced using a continuous casting and rolling method

(continuous casting and rolling step SO1). In this continuous casting and rolling step

SO1, for example, a continuous casting and rolling facility shown in FIG. 2 is used.

[0043]

The continuous casting and rolling facility shown in FIG. 2 has a melting

furnace A, a holding furnace B, a casting launder C, a belt-wheel type continuous casting

apparatus D, a continuous rolling device E, and a coiler F.

[0044]

As the melting furnace A, in the present embodiment, a shaft furnace having a

cylindrical furnace main body is used.

In the lower portion of the furnace main body, a plurality of burners (not shown)

is disposed in the circumferential direction in a multistep pattern in the vertical direction.

In addition, electrolytic copper, which is a raw material, is charged from the upper

portion of the furnace main body and is melted through the combustion of the burners,

and molten copper is continuously produced.

[0045]

The holding furnace B is a furnace for temporarily storing the molten copper

produced in the melting furnace A while holding the molten copper at a predetermined

temperature and for sending a certain amount of the molten copper to the casting launder

C.

[0046]

The casting launder C is a tube for transferring the molten copper sent from the

holding furnace B to a tundish 11 disposed above the belt-wheel type continuous casting

apparatus D. The casting launder C is sealed with, for example, an inert gas such as Ar

or a reducing gas. Meanwhile, the casting launder C is provided with degassing means

(not shown) for removing oxygen and the like in the molten metal by stirring the molten

copper using the inert gas.

[0047]

The tundish 11 is a storage tank provided to continuously supply the molten

copper to the belt-wheel type continuous casting apparatus D. A pouring nozzle 12 is

disposed in the tundish 11 on the end side in the flow direction of the molten copper, and

the molten copper in the tundish 11 is supplied to the belt-wheel type continuous casting apparatus D through the pouring nozzle 12.

[0048]

Here, in the present embodiment, alloy element addition means (not shown) is

provided in the casting launder C and the tundish 11, and the above-described elements

(Co, P, Sn, and the like) are added to the molten copper.

[0049]

The belt-wheel type continuous casting apparatus D has a casting wheel 13

having trenches formed on the outer circumferential surface and an endless belt 14 being

revolved around the casting wheel so as to come into contact with a part of the outer

circumferential surface of the casting wheel 13. In the belt-wheel type continuous

casting apparatus D, the molten copper is poured through the pouring nozzle 12 into

spaces formed between the trenches and the endless belt 14, and the molten copper is

cooled and solidified, thereby continuously casting a rod-shaped copper alloy ingot 21.

[0050]

The continuous rolling device E is coupled to the downstream side of the

belt-wheel type continuous casting apparatus D.

The continuous rolling device E continuously rolls the copper alloy ingot 21

produced from the belt-wheel type continuous casting apparatus D so as to produce the

copper wire rod 50 having a predetermined outer diameter.

The copper wire rod 50 produced from the continuous rolling device E is wound

around the coiler F through a cleaning and cooling device 15 and a flaw detector 16.

Here, the outer diameter of the copper wire rod 50 produced using the

above-described continuous casting and rolling facility is set, for example, in a range of 8

mm to 40 mm, and, in the present embodiment, is set to 27 mm.

[0051]

Next, a solid solution treatment is carried out on the obtained copper wire rod 50

(solid solution treatment step S02). In this solid solution treatment step S02, the copper

wire rod is heated in the atmosphere under conditions of a holding temperature in a range

of 900°C to 1,000°C and a holding time in a range of 30 minutes to 600 minutes.

Meanwhile, in the solid solution material after the solid solution treatment step

S02, the electrical conductivity is set to 45% or less.

[0052]

Next, cold working is carried out on the solid solution material after the solid

solution treatment step S02 (cold working step S03). In this cold working step S03, the

working ratio is preferably set in a range of 10% to 99%. Meanwhile, as a working

method, it is possible to use a variety of means such as wire drawing and rolling.

[0053]

Next, an aging heat treatment is carried out on the cold-worked material after the

cold working step S03 (aging heat treatment step S04). In this aging heat treatment step

S04, precipitates made of a compound containing Co and P as the main components are

precipitated.

Here, in the aging heat treatment step S04, the aging heat treatment is carried out

under conditions of a heat treatment temperature of 200°C to 700°C and a holding time

of one hour to 30 hours.

[0054]

With the above-described steps, the copper alloy member made of the copper

alloy which is the present embodiment is manufactured.

Meanwhile, cold working and a heat treatment may be further carried out after

the aging heat treatment step S04 as necessary.

[0055]

According to the copper alloy which is the present embodiment provided with

the above-described constitution, any one or more of B, Cr, and Zr are included, and,

when the amount of B is represented by X (massppm), the amount of Cr is represented by

Y (massppm), and the amount of Zr is represented by Z (massppm), Expression (1):

1(X/5)+(Y/50)+(Z/100) is satisfied, and thus, even in a case in which the copper alloy is

heated and held at a high temperature, the coarsening of the crystal grain diameters is

suppressed due to these elements, and the wire drawability and the high-temperature

elongation are excellent. In addition, it becomes possible to carry out a sufficient solid

solution treatment, and it is possible to improve the strength and the electrical

conductivity.

Meanwhile, the contents of B, Cr, and Zr satisfy Expression (2): X+Y+Z<1,000,

and thus it is possible to suppress the degradation of the castability or the generation of

casting breaking or the like.

[0056]

Here, in the copper alloy which is the present embodiment, Expression (3):

1(2X/5)+(2Y/50) is satisfied, and thus, even in a case in which the copper alloy is

heated and held at a high temperature, the coarsening of the crystal grain diameters can

be further suppressed.

In addition, Expression (4): Y<400 is satisfied, and thus it is possible to further

suppress the degradation of the castability.

[0057]

In addition, in the present embodiment, furthermore, in a case in which either or

both of 0.01 mass% or more and 0.15 mass% or less of Ni and 0.005 mass% or more and

0.07 mass% or less of Fe are included, due to Ni and Fe, it is possible to miniaturize the

compound of Co and P, and the strength can be further improved.

[0058]

In addition, in the present embodiment, furthermore, in a case in which any one

or more of 0.002 mass% or more and 0.5 mass% or less of Zn, 0.002 mass% or more and

0.25 mass% or less of Mg, and 0.002 mass% or more and 0.25 mass% or less of Ag are

included, it is possible to detoxicate S that is mixed into the copper alloy in a recycle

process of a copper material with Zn, Mg, and Ag, and it is possible to prevent

intermediate temperature embrittlement and improve the strength and ductility of the

copper alloy member.

[0059]

In addition, in the present embodiment, in the solid solution material after the

solid solution treatment step S02, the electrical conductivity is set to 45% or less, and

thus the solid solution material is sufficiently solutionized. Therefore, it is possible to

finely and uniformly disperse the precipitates by the subsequent aging heat treatment step

S04, and a copper alloy member which is excellent in terms of strength and electrical

conductivity can be obtained.

[0060]

(Second Embodiment)

Next, a second embodiment of the present invention will be described.

A copper alloy which is the second embodiment of the present invention has a

and B in a range of 5 massppm or more and 1,000 massppm or less and furthermore, a

Cu balance containing inevitable impurities.

That is, in the first embodiment, out of B, Cr, and Zr, only B is added to the

copper alloy. Meanwhile, when the amount of B is set to be in a range of 5 massppm or more and 1,000 massppm, and Expression (1), Expression (2), Expression (3), and

Expression (4) are satisfied.

[0061]

Meanwhile, similar to the first embodiment, furthermore, either or both of 0.01

mass% or more and 0.15 mass% or less of Ni and 0.005 mass% or more and 0.07 mass%

or less of Fe may be included.

In addition, furthermore, any one or more of 0.002 mass% or more and 0.50

mass% or less of Zn, 0.002 mass% or more and 0.25 mass% or less of Mg, and 0.002

mass% or more and 0.25 mass% or less of Ag may be included.

[0062]

Here, B is an element having an action of suppressing the coarsening of the

crystal grains when the copper alloy is held at a high temperature as described above.

When the amount of B is set to 5 massppm or more, it is possible to exhibit the

above-described action effect of suppressing the coarsening of the crystal grains. On

the other hand, when the amount of B is set to 1,000 massppm or less, it is possible to

suppress the degradation of the castability and the workability.

Based on what has been described above, in the present embodiment, the

amount of B is set to be in a range of 5 massppm or more and 1,000 massppm or less.

Meanwhile, in order to reliably exhibit the above-described action effect, the

lower limit of the amount of B is preferably set to 10 massppm and more preferably set to

15 massppm more. On the other hand, in order to reliably suppress the degradation of

the castability and the workability, the upper limit of the amount of B is preferably set to

200 massppm or less and more preferably set to 100 massppm or less.

[0063]

Next, a method of manufacturing a copper alloy member made of the above-described copper alloy will be described. FIG. 3 shows a flowchart of a method of manufacturing a copper alloy member which is the embodiment of the present invention.

First, a variety of raw materials are weighed so as to obtain the above-described

composition, the raw materials are melted using a vacuum melting furnace, a molten

copper alloy having adjusted components was injected into a casting mold, and a copper

alloy ingot made of the copper alloy having the above-described composition is produced

(melting casting step Si1). Meanwhile, in a case in which mass production is taken into

account, it is preferable to use a continuous casting method or a semi-continuous casting

method.

[0064]

Meanwhile, in this copper alloy ingot, the average crystal grain size after cold

rolling of a working ratio of 50% and a heat treatment at 950°C for one hour is set to 400

pm or less.

In addition, in this copper alloy ingot, the electrical conductivity after a heat

treatment at 950°C for one hour is set to 45%IACS or less.

[0065]

Next, a solid solution treatment is carried out on the obtained copper alloy ingot

(solid solution treatment step S12). In this solid solution treatment step S12, the copper

alloy ingot is heated in the atmosphere under conditions of a holding temperature in a

range of 900°C to 1,000°C and a holding time in a range of 30 minutes to 600 minutes.

S12, the electrical conductivity is set to 45% or less.

[0066]

Next, hot working is carried out on the solid solution material after the solid

solution treatment step S12 (hot working step S13). In this hot working step S13, the

hot working temperature is preferably set in a range of 700°C to 1,000°C, and the

working ratio is preferably set in a range of 10% to 99%. In addition, after the working,

quenching is carried out on the solid solution material by water cooling or the like.

[0067]

Next, cold working is carried out on the hot-worked material after the hot

working step S13 (cold working step S14). In this cold working step S14, the working

ratio is preferably set in a range of 10% to 99%. Meanwhile, as a working method, it is

possible to use a variety of means such as wire drawing and rolling.

[0068]

cold working step S14 (aging heat treatment step S15). In this aging heat treatment step

S15, precipitates made of a compound containing Co and P as the main components are

precipitated.

Here, in the aging heat treatment step S15, the aging heat treatment is carried out

of one hour to 30 hours.

[0069]

With the above-described steps, the copper alloy member made of the copper

alloy which is the present embodiment is manufactured.

Meanwhile, cold working and a heat treatment may be further carried out after

the aging heat treatment step S15 as necessary.

[0070]

The copper alloy which is the present embodiment provided with the above-described constitution has a composition including 0.05 mass% or more and 0.70 mass% or less of Co, 0.02 mass% or more and 0.20 mass% or less of P, and 0.005 mass% or more and 0.70 mass% or less of Sn, and furthermore, B in a range of 5 massppm or more and 1,000 massppm or less with a Cu balance containing inevitable impurities, and thus, even in a case in which the copper alloy is heated and held at a high temperature, coarsening of the crystal grain diameters is suppressed due to B, and the workability and the high-temperature elongation are excellent. In addition, it becomes possible to carry out a sufficient solid solution treatment, and it is possible to improve the strength and the electrical conductivity. Furthermore, the amount of B is set to 1,000 massppm or less, and thus it is possible to suppress the degradation of the castability or the generation of casting breaking.

[0071]

In addition, in the copper alloy ingot of the present embodiment, the average

crystal grain size after cold rolling of a working ratio of 50% and a heat treatment at

950°C for one hour is set to 400 pm or less, and thus the crystal grains coarsening during

the holding of the copper alloy ingot at a high temperature is suppressed, and it is

possible to suppress the degradation of the workability, high-temperature embrittlement,

and the like attributed to the coarsening of the crystal grains even when the solid solution

material is sufficiently solutionized by carrying out the solid solution treatment under a

high-temperature condition in the solid solution treatment step S13.

Furthermore, in the copper alloy ingot of the present embodiment, the electrical

conductivity after a heat treatment at 950°C for one hour is set to 45%IACS or less, and

thus it is possible to sufficiently carry out the solid solution treatment.

Therefore, when the solid solution treatment is carried out under a

high-temperature condition, in the subsequent aging heat treatment step S15, it becomes possible to finely and uniformly disperse precipitates made of a compound containing Co and P as main components, and a copper alloy member which is excellent in terms of strength and electrical conductivity can be obtained.

[0072]

(Third Embodiment)

Next, a third embodiment of the present invention will be described.

A copper alloy trolley wire which is the third embodiment of the present

invention has a composition including 0.12 mass% or more and 0.40 mass% or less of Co,

0.04 mass% or more and 0.16 mass% or less of P, 0.01 mass% or more and 0.50 mass%

or less of Sn, and any one or more of B, Cr, and Zr, and furthermore, a Cu balance

containing inevitable impurities. An amount of B is represented by X (massppm). An

amount of Cr is represented by Y (massppm). An amount of Zr is represented by Z

(massppm). X and Y satisfy the following Expressions (1) and (2);

Expression (1): 1 (X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z<1,000.

[0073]

Furthermore, in the present embodiment, the amounts of B, Cr, and Zr satisfy

the following Expressions (3) and (4);

Expression (3): 1 (2X/5)+(2Y/50),

Expression (4): Y<400.

[0074]

Meanwhile, in the present embodiment, the amount of B may be in a range of 5

massppm or more and 1,000 massppm or less, and Expression (1), Expression (2),

Expression (3), and Expression (4) may be satisfied.

[0075]

Here, in the present embodiment, in order to ensure the characteristics (strength

and electrical conductivity) as a trolley wire, the amount of Co is set to be in a range of

0.12 mass% or more and 0.40 mass% or less, the amount of P is set to be in a range of

0.04 mass% or more and 0.16 mass% or less, and the amount of Sn is set to be in a range

of 0.01 mass% or more and 0.50 mass% or less.

Meanwhile, in the copper alloy trolley wire which is the present embodiment,

the tensile strength is preferably 532 MPa or more, and the electrical conductivity is

preferably 76%IACS or more.

[0076]

In addition, in the present embodiment, in order to suppress the coarsening of

the crystal grain diameters and improve the wear characteristics and the fatigue

characteristics, similar to the first embodiment, any one or more of B, Cr, and Zr are

included, and Expression (1), Expression (2), Expression (3), and Expression (4) are

satisfied.

In addition, in order to suppress the coarsening of the crystal grain diameters and

improve the wear characteristics and the fatigue characteristics, similar to the first

embodiment, the copper alloy trolley wire may contain B in a range of 5 massppm or

more and 1,000 massppm or less.

[0077]

Next, a method of manufacturing a copper alloy trolley wire made of the copper

alloy will be described. FIG. 4 is a flowchart of a method of manufacturing a copper

alloy trolley wire which is an embodiment of the present invention.

First, a copper wire rod made of a copper alloy having the above-described

(continuous casting and rolling step S21). In this continuous casting and rolling step

S21, similar to the first embodiment, for example, the continuous casting and rolling

facility shown in FIG. 2 is used.

Here, the outer diameter of the copper wire rod being produced using the

above-described continuous casting and rolling facility is set to, for example, 8 mm to 40

mm and is set to 27 mm in the present embodiment.

[0078]

Next, a solid solution treatment is carried out on the obtained copper wire rod

(solid solution treatment step S22). In this solid solution treatment step S22, the copper

S22, the electrical conductivity is set to 45% or less.

[0079]

solution treatment step S22, thereby obtaining a copper wire material (primary cold

working step S23). In the primary cold working step S23, the working ratio is

preferably set in a range of 5% to 90%. Meanwhile, as a working method, it is possible

to use a variety of means such as cold wire drawing, peeling, trenched wire drawing, and

rolling.

[0080]

Next, an aging heat treatment is carried out on the copper wire material after the

primary cold working step S23 (aging heat treatment step S24). In this aging heat

treatment step S24, precipitates made of a compound containing Co and P as the main

components are precipitated.

Here, in the aging heat treatment step S24, the aging heat treatment is carried out under conditions of a heat treatment temperature of 300°C to 600°C and a holding time of 60 minutes to 1,500 minutes.

In the aging-heat-treated material being obtained by the aging heat treatment

step S24, the electrical conductivity is preferably 76ACS% or more.

[0081]

Next, cold working is further carried out on the aging heat-treated material after

the aging heat treatment step S24 (secondary cold working step S25). In the secondary

cold working step S25, the working ratio is preferably set in a range of 5% to 90%.

Meanwhile, as a working method, it is possible to use a variety of means such as cold

wire drawing, trenched wire drawing, and rolling.

[0082]

With the above-described steps, the copper alloy trolley wire made of the copper

alloy which is the present embodiment is manufactured.

Meanwhile, a heat treatment and cold working may be further carried out after

the secondary cold working step S25 as necessary.

[0083]

The copper alloy trolley wire which is the present embodiment provided with

the above-described constitution has a composition including 0.12 mass% or more and

0.40 mass% or less of Co, 0.04 mass% or more and 0.16 mass% or less of P, and 0.01

mass% or more and 0.50 mass% or less of Sn, and furthermore, any one or more of B, Cr,

and Zr, a Cu balance containing inevitable impurities and is thus capable of satisfying the

strength and the electrical conductivity being demanded as a trolley wire.

In addition, due to B, Cr, and Zr, even in a case in which the copper alloy trolley

wire is heated and held at a high temperature, the coarsening of the crystal grain

diameters can be suppressed, and it is possible to further improve the wear characteristics and the fatigue characteristics. In addition, it becomes possible to carry out a sufficient solid solution treatment, and it is possible to further improve the strength and the electrical conductivity.

[0084]

Furthermore, the method of manufacturing a copper alloy trolley wire of the

present embodiment includes the continuous casting and rolling step S21 of continuously

producing a copper wire rod and the solid solution treatment step S22 of carrying out a

solid solution treatment on the obtained copper wire rod, and, in the solid solution

treatment step S22, the holding temperature is set to be in a range of 900°C to 1,000°C,

and the holding time at the holding temperature is set to be in a range of 30 minutes to

600 minutes, and thus it is possible to sufficiently solve the segregation of Co and P in

the copper wire rod manufactured using a continuous casting and rolling method.

In addition, in the aging heat treatment step S24, the heat treatment temperature

is set to be in a range of 300°C to 600°C, and the holding time at the heat treatment

temperature is set to be in a range of 60 minutes to 1,500 minutes, and thus it is possible

to reliably carry out the aging treatment, and Co and P can be precipitated. Therefore, it

becomes possible to manufacture a copper alloy trolley wire that is excellent in terms of

strength and electrical conductivity.

[0085]

Hitherto, the copper alloy, the copper alloy ingot, the solid solution material of

copper alloy, and the copper alloy trolley wire which are the embodiments of the present

invention have been described, but the present invention is not limited thereto, and the

embodiments can be appropriately modified within the scope of the technical idea of the

present invention.

For example, in the first embodiment and the third embodiment, as an example of the method of manufacturing the copper alloy member (the copper alloy trolley wire), a manufacturing method in which the belt-wheel type continuous casting apparatus D shown in FIG. 2 is used has been described, but the manufacturing method is not limited thereto, and a twin belt-type continuous caster or the like may be used. In addition, a continuous-cast wire rod may also be manufactured using an upward continuous caster, a transverse continuous caster, and a hot top continuous caster.

In addition, as in the second embodiment, a copper alloy ingot may be

manufactured, and the solid solution treatment may be carried out on this copper alloy

ingot.

Examples

[0086]

Hereinafter, the results of a confirmation test carried out to confirm the

effectiveness of the present invention will be described.

[0087]

A variety of raw materials were weighed so as to obtain a composition shown in

Table 1-3, and the raw materials were melted using a vacuum melting furnace. After

the raw materials were burned through, the molten metal was held for 10 minutes and

injected into a casting mold in an inert gas atmosphere at a molten metal temperature of

1,200°C, thereby obtaining a copper alloy ingot having ingot dimensions of 50x80x 150

mm (approximately 5 kg).

Next, on the copper alloy ingot, a solid solution treatment was carried out under

conditions shown in Table 4-6 using an air atmosphere furnace.

The solid solution material after the solid solution treatment was rolled using a hot rolling device at a working ratio of 80% and then cooled with water.

The obtained hot-rolled material was cold-worked at a working ratio of 80%,

and then an aging heat treatment was carried out using the air atmosphere furnace under

conditions of being held at 500°C for one hour.

[0088]

(Average Crystal Grain Size)

Cold working of a working ratio of 50% was carried out on the copper alloy

ingot obtained as described above, held at 950°C for one hour using the air atmosphere

furnace, and then cooled with water. The obtained test specimen was polished with

emery paper and a buff, etched with an etchant, and then observed using an optical

microscope at an appropriate magnification, and the average crystal grain size was

computed using an area method specified by JIS H0321. The evaluation results are

shown in Table 4-6.

[0089]

(High-Temperature Elongation)

A test specimen having a shape specified by JIS G0567 was sampled from the

hot-rolled material, and a tensile test was carried out at 500°C, thereby evaluating the

elongation. The evaluation results are shown in Table 4-6.

[0090]

(Strength)

A test specimen having a shape specified by JIS Z2241 was sampled from a

copper alloy member after an aging heat treatment, and a tensile test was carried out at

room temperature, thereby evaluating the tensile strength. The evaluation results are

shown in Table 4-6.

[0091]

(Electrical conductivity)

The electrical conductivity of the copper alloy member after an aging heat

treatment was measured using a four-terminal method. The evaluation results are

shown in Table 4-6.

[0092]

(Wire Drawability)

Cold wire drawing of a working ratio of 80% was carried out on the

above-described hot-worked material, thereby working the hot-worked material to a

copper alloy wire having a diameter of 4 mm. The number of times of wire breaking

when the copper alloy wire was drawn until the drawn wire length reached 100 m in a

diameter of 4 mm was evaluated, and an equivalent value of the number of times of wire

breaking occurring per 10 m was considered as the wire drawability. The evaluation

results are shown in Table 4-6.

[0093]

(Castability)

A variety of raw materials were weighed so as to obtain a composition shown in

the table, and the raw materials (3 kg) were charged into an alumina crucible. The raw

materials were melted in an Ar gas atmosphere, burned through, and then held for 20

minutes at 1,200°C. The molten metal was gently poured into a separately-prepared

mold, a film generated on the molten steel surface was left in the aluminum crucible, and

the weight of the film was measured. The evaluation results are shown in Table 4-6.

[0094]

(Casting Breaking)

The raw materials were melted using a vacuum melting furnace at 1,200C and

then cast in an H-shaped metal die shown in FIGS. 5A and 5B. Meanwhile, the

H-shaped metal die had been heated to 100°C in advance. The casting product was

cooled in the atmosphere to room temperature, and then the presence or absence of

breaking in an H shape central portion was evaluated. The evaluation results are shown

in Table 4-6.

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atc ~c ~c ~c ~c c ~c ~c ~0 c ~c oc c r-- =~ oc 'T r- m~ oc N~ ol m c~ W) N~ N~ ol c~ C.,~~~~~~~~~~~~ o- C.- r- - ;- co - 0 - co c o co

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cz m m m m m m m m m m

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Q -Ur ~ )f)r r ~ ~r~r r ~ ~r~r r ~>~r

[0101]

In Comparative Examples 1 and 2, the contents of B, Zr, and Cr were below the

ranges of the present invention, the average crystal grain sizes were great, and the wire

drawability, the high-temperature elongation, and the strength were insufficient.

In Comparative Examples 3 and 4, the contents of B, Zr, and Cr were above the

ranges of the present invention, the castability was poor, and casting breaking was also

confirmed in Comparative Example 3. In addition, the electrical conductivity also

became poor.

In Comparative Example 51, the contents of Ni and Fe were above the ranges of

the present invention, and, In Comparative Example 51, the contents of Zn, Mg, and Ag

were above the ranges of the present invention, and the electrical conductivity became

poor.

[0102]

In contrast, according to the invention examples, the average crystal grain sizes

were small, and the wire drawability and the high-temperature elongation are excellent.

In addition, the castability was also favorable, and casting breaking was not confirmed.

Furthermore, the strength and the electrical conductivity were excellent.

Here, in Invention Example 1-3, neither Cr nor Zr were included, and the

castability was particularly preferred. In addition, in Invention Examples 51 to 63 to

which Fe, Ni, Zn, Mg, and Ag were added, the strength further improved.

[0103]

Based on what has been described above, it was confirmed that, according to the

invention examples, it is possible to provide a copper alloy which is capable of

suppressing the coarsening of the crystal grain diameters even in a case in which a solid

solution treatment is carried out, is excellent in terms of wire drawability and high-temperature elongation, and is excellent in terms of strength and electrical conductivity.

[0104]

A copper wire rod (<27 mm) having a composition shown in Table 7 was

manufactured using the continuous casting and rolling facility shown in FIG. 2.

Next, a solid solution treatment was carried out on this copper wire rod under

conditions shown in Table 7 using an air atmosphere furnace.

Cold wire drawing (working ratio: 77%) was carried out on the solid solution

material after the solid solution treatment, thereby obtaining a copper wire material.

In addition, an aging heat treatment was carried out on this copper wire material

under conditions shown in Table 7 using the air atmosphere furnace.

Next, cold wire drawing was carried out on the aging-heat-treated material so

that the total working ratio from the copper wire rod reached 81%.

[0105]

(Strength)

A test specimen having a shape specified by JIS Z2241 was sampled from a

copper alloy trolley wire, and a tensile test was carried out at room temperature, thereby

evaluating the tensile strength. The evaluation results are shown in Table 8.

[0106]

(Electrical conductivity)

The electrical conductivity of the copper alloy trolley wire was measured using a

four-terminal method. The evaluation results are shown in Table 8.

[0107]

(Wire Drawability)

Cold wire drawing of a working ratio of 99% was carried out on the

above-described copper wire rod, thereby working the copper wire rod to a copper wire

material having a diameter of 1 mm. The number of times of wire breaking when the

copper wire material was drawn until the drawn wire length reached 500 m in a diameter

of 1 mm was evaluated, and an equivalent value of the number of times of wire breaking

occurring per 10 m was considered as the wire drawability. The evaluation results are

shown in Table 8.

[0108]

(Hardness)

A test specimen was sampled from the obtained copper alloy trolley wire,

polished using emery paper and a buff, and etched with an etchant, and the Vickers

hardness was measured using a method specified by JIS Z 2244. The measurement was

carried out five times, and the average value and the standard deviation were computed.

The evaluation results are shown in Table 8. Meanwhile, in a related art example, the

alloy composition significantly differed, and thus the hardness was not measured.

[0109]

(Average Crystal Grain Size)

A test specimen was sampled from the obtained copper alloy trolley wire,

polished using emery paper and a buff, etched with an etchant, and then observed using

an optical microscope, and the average crystal grain size was computed using the area

method specified by JIS H0321, the evaluation results are shown in Table 8. Meanwhile,

in the related art example, the alloy composition significantly differed, and thus the

average crystal grain size was not measured.

[0110]

(Laboratory Fatigue Characteristics)

A sheet material having a width of 10 mm and a thickness of 4 mm was cut out

from the solid solution material after the solid solution treatment, and cold rolling of a

working ratio of 50% was carried out so as to obtain a thickness of 2 mm. After that, an

aging heat treatment was carried out under conditions shown in Table 7 using the air

atmosphere furnace, cold rolling of a working ratio of 75% was carried out so as to

obtain a thickness of 0.5 mm, and the sheet material was cut to a length of 60 mm using a

jaw. In addition, burrs on an end surface of the obtained test specimen were removed

using emery paper No. 1500.

In addition, the test specimen was set in a thin sheet fatigue tester with a set

length of 30 mm according to Measuring Method of Fatigue Property of Thin Sheets and

Stripes by Japanese Copper and Brass Association (JCBAT308: 2002). Inaddition,the

number of times of vibration generated until breakage was measured by changing the

strain amplitude at a frequency of 50 Hz.

The ratio of the amplitude amount to the set length of the test specimen was

defined as the strain amplitude, and the laboratory fatigue characteristics were evaluated

using the breakage service life under a condition of the strain amplitude being 6x 10-2.

Specifically, a test specimen for which the number of times of vibration applied until

breakage under the condition of the strain amplitude being 6x 10-2 was 107 times or more

was evaluated as "A", and a test specimen for which the number of times of vibration

was less than 107 times was evaluated as "B". The evaluation results are shown in

Table 8.

[0111]

(Fatigue Characteristics)

The fatigue characteristics of Invention Example 82, Comparative Example 71,

and the related art example were evaluated using a testing device shown in FIG. 6. As shown in FIG. 6, both ends (fixation side (FS) and movable side (MS)) of the copper alloy trolley wire were fixed (FX), a tensile force (TF) was imparted, vibration was applied (V) to a longitudinal-direction central portion of the copper alloy trolley wire, and the number of times of vibration applied until breakage was considered as the fatigue service life (times). The evaluation results are shown in Table 8.

[0112]

(Wear Characteristics)

The wear characteristics of a copper alloy trolley wire (TW) were evaluated

using a testing device shown in FIG. 7. The copper alloy trolley wire was wound

around an outer circumferential surface of a disc (DS) and caused to slide into contact

with a sliding plate (SP) (template: T3-2) of a pantograph (PG) by rotating the disc.

Meanwhile, the pantograph was moved in a direction orthogonal to a rotation direction

(RD) of the disc (horizontal movement (HM)) in an amplitude of 200 mm every

slide-contact length of the copper alloy trolley wire (TW) of 240 m.

The measurement results of the wear ratios of the trolley wires (TW) measured

by carrying out a wear test in Invention Example 82 and the related art example using

two kinds of sliding plates (SP) (templates: T3-2 and N5C-5) under two conditions of no

energization (no water pouring (W)) and an energization current of 200 A (with water

pouring (W)) are shown in FIG. 9. Meanwhile, the sliding rate is 200 km/hour, and the

test time is two hours.

Lr) Er n r

m~ m zmm cz cz

000000001000100 01

cz ~I U -~~-~~ c~c~ ~c c~ ~c c~ ~ c c~ cz

c~ ~ c c~c~ ~ c c~c~ r--c c~ c c c~ ~c c

.- z

0 ,- z ~>

[0114]

[Table 8]

Standard AeaecytlLbrtr aiu Drawability Strength Conductivity Hardness deviationof Avera crystal Lacharacterifatigue (times/m10 ) (MPa) (%IACS) (HV) hardness (pm) (tis (HV) (pm) (times)

71 0.0 550 78.1 190 4.2 110 A 72 0.0 554 78.0 194 3.6 70 A

73 0.0 556 77.1 197 5.2 70 A 74 0.3 556 78.1 195 1.3 170 A 75 1.1 560 78.5 196 4.5 350 A 76 1.1 545 80.2 188 3.3 70 A

77 1.3 561 76.9 195 2.9 70 A

Invention 78 1.3 546 80.5 184 1.6 70 A Example 79 1.4 559 76.4 193 6.1 70 A 80 1.2 554 79.5 190 5.5 70 A

81 1.2 558 77.1 192 4.2 70 A 82 0.0 552 77.9 191 4.1 70 A 83 0.0 545 81.2 185 3.3 90 A 84 0.0 546 82.1 183 1.2 70 A 85 0.0 545 76.3 186 3.8 90 A 86 0.0 546 77.2 185 3.9 80 A Comparative 71 9.5 539 78.3 178 11.6 1100 B

Related Art Example 0.0 550 79.0 - - - B *Laboratory fatigue characteristics: the number of times of vibration applied at a strain amplitude (6x 10-2) until breakage A: 107 times or more, B: less than 107 times

[0115]

In the invention examples, the wire drawability, the strength, and the electrical

conductivity were excellent. In addition, the hardness was higher than in the

comparative examples, and the standard deviation also became small. In addition, the

average crystal grain size became smaller than in the comparative examples. In

addition, as a result of the laboratory fatigue characteristics evaluation, the laboratory

fatigue characteristics were more favorable than in the comparative examples and the

related art example.

Furthermore, as a result of evaluating the fatigue characteristics and the wear characteristics using the measurement devices shown in FIG. 6 and FIG. 7, it was confirmed that, in Invention Example 82 in which the hardness was high and the average crystal grain size was small, the trolley wire was more favorable than the trolley wire

(PHC trolley wire) of the related art example.

In addition, in Invention Examples 83 to 86, the conditions for the solid solution

treatment step and the aging heat treatment step were changed, but it was confirmed that,

if the conditions are in the ranges of the present invention, it is possible to manufacture a

copper alloy trolley wire that is excellent in terms of wire drawability, strength, and

electrical conductivity, has a high hardness and a decreased average crystal grain size,

and is excellent in terms of fatigue characteristics and wear characteristics.

Based on what has been described above, it was confirmed that, according to the

invention examples, it is possible to provide a copper alloy trolley wire that is excellent

in terms of strength and electrical conductivity and is more favorable in terms of fatigue

characteristics and wear characteristics than in the related art.

Industrial Applicability

[0116]

According to the present invention, it becomes possible to provide a copper

alloy which is excellent in terms of workability and high-temperature elongation and is

excellent in terms of strength and electrical conductivity, a copper alloy ingot, a solid

solution material of copper alloy, and a copper alloy trolley wire that is excellent in terms

of wear characteristics and fatigue characteristics and a method of manufacturing a

copper alloy trolley wire.

Reference Signs List

[0117]

11 TUNDISH

12 POURING NOZZLE

13 CASTING WHEEL

14 ENDLESS BELT

15 CLEANING AND COOLING DEVICE

16 FLAW DETECTOR

21 ROD-SHAPED COPPER ALLOY INGOT

50 COPPER WIRE ROD

A MELTING FURNACE B HOLDING FURNACE C CASTING LAUNDER D BELT-WHEEL TYPE CONTINUOUS CASTING APPARATUS E CONTINUOUS ROLLING DEVICE F COILER EC ELECTROLYTIC COPPER FS FIXATION SIDE FX FIX V VIBRATION APPLICATION MS MOVABLE SIDE TF TENSILE FORCE R RESISTANCE FOR LIMITING CURRENT PG PANTOGRAPH OL OVERLAP DS DISC RD ROTATION DIRECTION MP SLIDE-CONTACT SURFACE WIDTH MEASUREMENT POINT TRD TROLLEY WIRE ROTATION DIRECTION SPS SLIDING PLATE STATUS HM HORIZONTAL MOVEMENT W WATER POURING TW TROLLEY WIRE SP SLIDING PLATE

Claims

CLAIMS What is claimed is:

1. A copper alloy having a composition including:

0.05 mass% or more and 0.70 mass% or less of Co; 0.02 mass% or more and

0.20 mass% or less of P; 0.005 mass% or more and 0.70 mass% or less of Sn; one or

more of B, Cr, and Zr; and a Cu balance containing inevitable impurities,

wherein X, Y, and Z satisfy the following Expressions (1) and (2),

Expression (1): 1 (X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z1,000, in a case where an amount of B is represented

by X (massppm), an amount of Cr is represented by Y (massppm), and an amount of Zr is

represented by Z (massppm), and

wherein the amount of B is in the range of 5 massppm or more and 1,000

massppm or less.

2. The copper alloy according to Claim 1,

wherein X and Y satisfy the following Expressions (3) and (4),

Expression (3): 1 (2X/5)+(2Y/50),

Expression (4): Y<400.

3. The copper alloy according toClaim 1 or 2, the composition of the copper alloy

further including either or both of:

0.01 mass% or more and 0.15 mass% or less of Ni; and

0.005 mass% or more and to 0.07 mass% or less of Fe.

4. The copper alloy according to any one of Claims I to 3, the composition of the

copper alloy further including any one or more of:

0.002 mass% or,more and 0.5 mass%;or less of Zn;

0.002 mass% or more and 0.25 mass% or less of Mg; and

0.002 mass% or more and 0.25 mass% or less of Ag.

5. A copper alloy ingot having the composition of the copper alloy according to any

one of Claims I to 4,

wherein an average crystal grain size after cold rolling of a working ratio of 50%

and a heat treatment at 950°C for one hour is 400 pm or less.

6. The copper alloy ingot according to Claim 5,

wherein an electrical conductivity after the heat treatment at 950°C for one hour

is 45%IACS or less.

7. A solid solution material of a copper alloy having the composition of the copper

alloy according to any one of Claims 1 to 4,

wherein an electrical conductivity is 45%IACS or less.

8. A copper alloy trolley wire having a composition including:

0.12 mass% or more and 0.40 mass% or less of Co; 0.04 mass% or more and

0.16 mass% or less of P; 0.01 mass% or more and 0.50 mass% or less of Sn; one or more

of B, Cr, and Zr; and a Cu balance containing inevitable impurities,

wherein X, Y, and Z satisfy the following Expressions (1) and (2),

Expression (1): 1<(X/5)+(Y/50)+(Z/100),

Expression (2): X+Y+Z1,000, in case where an amount of B is represented by

X (massppm), an amount of Cr is represented by Y (massppm), and an amount of Zr is

represented by Z (massppm), and

wherein the amount of B is in range of 5 massppm or more and 1,000 massppm

or less.

9. The copper alloy trolley wire according to Claim 8,

wherein X and Y satisfy the following Expressions (3) and (4),

Expression (3): 1 (2X/5)+(2Y/50),

Expression (4): Y<400.

10. A method of manufacturing the copper alloy trolley wire according to Claim 8 or 9,

the method comprising:

a continuous casting and rolling step of continuously producing a copper wire

rod;

a solid solution treatment step of carrying out a solution treatment on the copper

wire rod obtained;

a primary cold working step of producing a copper wire material by carrying out

cold working on a solution material after the solid solution treatment step;

an aging heat treatment step of carrying out an aging heat treatment on the

copper wire material; and

a secondary cold working step of carrying out cold working on an aging

heat-treated material after the aging heat treatment step,

wherein, in the solid solution treatment step, a holding temperature is set to be in

a range of 900°C or more and 1,000°C or less, and a holding time at the holding temperature is set to be in a range of 30 minutes or more and 600 minutes or less, and in the aging heat treatment step, a heat treatment temperature is set to be in a range of 300°C or more and 600°C or less, and a holding time at the heat treatment temperature is set to be in a range of 60 minutes or more and 1,500 minutes or less.