JPWO2019181320A1 - Manufacturing method of copper alloy wire and copper alloy wire - Google Patents

Abstract

An object of the present invention is to provide a copper alloy wire rod having excellent tensile strength and a method for producing the same, even when the diameter of the wire rod is reduced without impairing the excellent conductivity. It contains 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr and 0 to 1.0% by mass of Zr, and the balance is Cu and unavoidable. It is a copper alloy wire having an alloy composition composed of impurities, and when a cross section parallel to the longitudinal direction of the copper alloy wire is observed, it matches with Cu of the matrix in a rectangular observation region of 240 nm × 360 nm. The area ratio (A) of the precipitated precipitate is the following formula (I) (0.393 × x −0.589)% ≦ A ≦ (3.88 × x −5.81)% (I) ( In the formula (I), x represents the mass% of Ag).) Copper alloy wire rod.

Description

The present invention relates to a copper alloy wire having high tensile strength and a method for producing the copper alloy wire, which can be used for, for example, brocade wire.

For example, a speaker is equipped with a coil and a diaphragm, and the coil vibrates when a current flows through the coil, and the diaphragm vibrates in conjunction with the vibration of the coil to produce sound. .. A brocade wire is used as the wire connecting the coil and the terminal of the base material. Therefore, the brocade wire is required to have high vibration durability that can withstand vibration caused by sound. Vibration durability is generally improved by thinning the wire due to the dimensional effect. On the other hand, if the diameter of the wire rod is reduced, the tensile durability is lowered, which makes it difficult to handle the wire rod during manufacturing, and there is a problem that the wire breakage or entanglement occurs and the yield is deteriorated.

Therefore, for example, as an alloy material having improved tensile strength, Ag: 8.0 to 20.0% by weight and Cr: 0.1 to 1.0% by weight are contained, and the balance is composed of Cu and unavoidable impurities. , And a copper alloy having a structure in which fine precipitates of Cr are dispersed in a substrate in which primary crystals and eutectic crystals are oriented in a fibrous form has been proposed (Patent Document 1).

However, in Patent Document 1, only fine precipitates of Cr are dispersed in the substrate in which the primary crystal and the eutectic are fibrously oriented, and the precipitation state of the fine precipitates composed of Cr is controlled. Not an organization.

Therefore, in the copper alloy of Patent Document 1, there is room for improvement in tensile strength when the diameter of the wire is reduced, which in turn improves the handleability during wire production, prevents disconnection and entanglement, and reduces the yield. There was room for improvement in improving it.

Japanese Patent Application No. 5-90832

In view of the above circumstances, an object of the present invention is to provide a copper alloy wire rod having excellent tensile strength and a method for producing the same, even when the diameter of the wire rod is reduced without impairing the excellent conductivity.

[1] Contains 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr and 0 to 1.0% by mass of Zr, and the balance is A copper alloy wire having an alloy composition consisting of Cu and unavoidable impurities.
When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the area ratio (A) of the precipitates precipitated in accordance with the Cu of the matrix in the rectangular observation area of 240 nm × 360 nm is
The following formula (I)
(0.393 x x-0.589)% ≤ A ≤ (3.88 x x-5.81)% (I)
(In formula (I), x represents the mass% of Ag.)
Copper alloy wire that is within the range of.
[2] The copper alloy wire rod according to [1], wherein the total content of at least one component selected from the group consisting of Mg, Cr and Zr is 0.01 to 3.0% by mass.
[3] The copper alloy wire rod according to [1] or [2], wherein the precipitate that is deposited in accordance with the Cu of the parent phase exists in a fibrous form along the longitudinal direction of the copper alloy wire rod.
[4] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average width of the precipitates precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. (W) is
The following formula (II)
(8.3 × d) nm ≦ W ≦ (24.9 × d) nm (II)
(In formula (II), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to [3], which is within the range of.
[5] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average length of the precipitates precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. (L) is
The following formula (III)
(11.3 / d) nm ≦ L ≦ (33.8 / d) nm (III)
(In formula (III), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to [3] or [4], which is within the range of.
[6] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average spacing of the precipitates precipitated in accordance with the Cu of the matrix in a rectangular observation area of 240 nm × 360 nm. (S) is
The following formula (IV)
(760 × x ^ -2.25) × dnm ≦ S ≦ (2300 × x ^ -2.25) × dnm (IV)
(In formula (IV), d represents the wire diameter (mm) of the copper alloy wire, and x represents the mass% of Ag.)
The copper alloy wire rod according to any one of [3] to [5], which is within the range of.
[7] The copper alloy wire rod according to any one of [1] to [6], wherein the precipitate is aligned in the same crystal axis direction with respect to Cu of the parent phase.
[8] A step of melting the raw material, a step of casting the melted raw material to obtain an ingot, a step of first heat-treating the copper alloy material obtained from the ingot, and a step of further performing a second heat treatment. The method for producing a copper alloy wire according to any one of [1] to [7], which comprises a step of finally drawing the copper alloy material subjected to the second heat treatment to obtain a copper alloy wire. hand,
The first heat treatment step is performed at a temperature of 700 ° C. or higher.
The second heat treatment step is performed at a temperature of 350 to 600 ° C.
Process degree log (A0 / A1) ^ 2 (in the formula, A0 is the cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material immediately before the final wire drawing process, and A1 is immediately after the final wire drawing process. A method for manufacturing a copper alloy wire rod having a cross-sectional area of 2.5 or more in the direction orthogonal to the longitudinal direction of the copper alloy material.
[9] The wire drawing process is performed between the step of obtaining the ingot and the first heat treatment step, and / or between the first heat treatment step and the second heat treatment step. Manufacturing method of copper alloy wire rod.

According to the aspect of the present invention, 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr and 0 to 1.0% by mass of Zr are used. Area ratio of precipitates that are consistently precipitated with Cu in the observation range of 240 nm × 360 nm in a cross section parallel to the longitudinal direction for a copper alloy wire containing an alloy composition in which the balance is Cu and unavoidable impurities. When (A) is within the above range, a copper alloy wire having excellent tensile strength can be obtained even when the diameter of the wire is reduced without impairing the excellent conductivity.

In this way, even when the diameter of the wire rod is reduced, a copper alloy wire rod having excellent tensile strength can be obtained, so that high vibration durability can be obtained, the handleability during wire rod manufacturing is improved, and the wire rod can be handled. The yield is improved by preventing disconnection and entanglement.

According to the aspect of the present invention, the total content of at least one component selected from the group consisting of Mg, Cr and Zr is 0.01 to 3.0% by mass, so that the vibration durability is further improved. This contributes to further improvement of tensile strength even when the diameter of the wire is reduced.

According to the aspect of the present invention, the precipitates that are precipitated in accordance with the Cu of the parent phase are present in a fibrous form along the longitudinal direction of the copper alloy wire, and the average width of the precipitates that are present in a fibrous form is present. (W), the average length (L) of the precipitate and / or the average interval (S) of the precipitate was within the above range, so that the vibration durability was further improved and the diameter of the wire was reduced. Even in this case, it contributes to further improvement of tensile strength.

It is an electron micrograph of a diffraction spot generated when an electron beam is incident on a Cu crystal in the [010] direction. It is an electron micrograph which shows the dark field image of a copper alloy wire. It is a graph which shows the result of having calculated the number of pixels of the white contrast part for every row about the binary | contrast of the dark field image.

The details of the copper alloy wire rod of the present invention will be described below. The copper alloy wire rod of the present invention contains 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr, and 0 to 1.0% by mass of Zr. A copper alloy wire containing an alloy composition in which the balance is Cu and unavoidable impurities, and when a cross section parallel to the longitudinal direction of the copper alloy wire is observed, the mother in a rectangular observation region of 240 nm × 360 nm. The area ratio (A) of the precipitate that is precipitated in accordance with the phase Cu is the following formula (I).
(0.393 x x-0.589)% ≤ A ≤ (3.88 x x-5.81)% (I)
(In formula (I), x represents mass% of Ag.).

[Alloy composition of copper alloy wire]
The copper alloy wire rod of the present invention contains 1.5 to 6.0% by mass of Ag (silver). Therefore, Ag is an essential additive component. Ag is solid-dissolved in Cu (copper), which is the parent phase, or crystallized as second-phase particles during casting of copper alloy material, or as second-phase particles by heat treatment after casting of copper alloy material. It is an element that exists in a precipitated state (in the present specification, these are collectively referred to as "precipitate") and exerts the effect of solid solution strengthening or dispersion strengthening. The second phase means a crystal having a different crystal structure from the parent phase (first phase) of Cu.

If the Ag content is less than 1.5% by mass, the effect of solid solution strengthening or dispersion strengthening is insufficient, and sufficient tensile strength and vibration durability cannot be obtained. On the other hand, when the Ag content exceeds 6.0% by mass, sufficient conductivity cannot be obtained and the raw material cost becomes high. From the above, the Ag content is set to 1.5 to 6.0% by mass from the viewpoint of obtaining excellent tensile strength even when the diameter of the wire is reduced without impairing the conductivity. The requirements for tensile strength and conductivity differ depending on the application of the copper alloy wire, but it is desirable to balance the tensile strength and conductivity by adjusting the Ag content within the range of 1.5 to 6.0% by mass. It is possible to set to. The Ag content is preferably 1.5 to 4.5% by mass from the viewpoint that a balance between tensile strength and conductivity can be obtained in a wide range of applications.

In the copper alloy wire rod of the present invention, in addition to Ag, which is an essential additive component, at least one selected from the group consisting of Mg (magnesium), Cr (chromium) and Zr (zirconium) as an optional additive component. It can contain elements.

All of Mg, Cr and Zr are mainly present in the parent phase Cu as a solid solution or a second phase state, and exhibit the effect of solid solution strengthening or dispersion strengthening as in the case of Ag. It is an element. Further, when it is contained together with Ag, it exists as a second phase of a ternary system or more such as a Cu-Ag-Zr system, and can contribute to further solid solution strengthening or dispersion strengthening.

From the above, the total content of at least one component selected from the group consisting of Mg, Cr and Zr is preferably 0.01% by mass or more from the viewpoint of sufficiently exerting the effect of solid solution strengthening or dispersion strengthening. 0.05% by mass or more is more preferable, and 0.10% by mass or more is particularly preferable. On the other hand, if the contents of Mg, Cr and Zr each exceed 1.0% by mass, excellent conductivity may not be obtained depending on the application. Therefore, the contents of Mg, Cr and Zr are set. Each is preferably 1.0% by mass or less, more preferably 0.7% by mass or less, and particularly preferably 0.5% by mass or less. Therefore, from the viewpoint of obtaining excellent tensile strength even when the diameter of the wire is reduced without impairing the conductivity, the total content of at least one component selected from the group consisting of Mg, Cr and Zr is 0. It is preferably 01 to 3.0% by mass, more preferably 0.05 to 2.1% by mass, and particularly preferably 0.10 to 1.5% by mass.

The rest other than the above-mentioned components are Cu and unavoidable impurities. Cu is the parent phase of the copper alloy wire rod of the present invention. Ag, which is an essential additive component, is present in the parent phase Cu in a solid solution state or in a state of being precipitated as a precipitate. Further, if necessary, at least one component selected from the group consisting of optional additive components Mg, Cr and Zr is present in the parent phase Cu in a solid solution state or in a state of being precipitated as a precipitate. doing.

The unavoidable impurities mean impurities at a content level that can be unavoidably contained in the manufacturing process of the copper alloy wire rod of the present invention. Inevitable impurities can also be a factor that lowers the conductivity depending on the content. Therefore, considering the decrease in conductivity, it is preferable to suppress the content of unavoidable impurities. Examples of unavoidable impurities include Ni, Sn, Zn and the like.

[Area ratio of precipitates precipitated in accordance with Cu in the matrix (A)]
In the copper alloy wire rod of the present invention, when observing a cross section parallel to the longitudinal direction thereof, a precipitate (hereinafter, “precipitate” which is deposited in accordance with the Cu of the parent phase in a rectangular observation region of 240 nm × 360 nm. The area ratio (A) of "matched precipitate") is the following formula (I).
(0.393 x x-0.589)% ≤ A ≤ (3.88 x x-5.81)% (I)
(In formula (I), x represents mass% of Ag.).

Therefore, in the copper alloy wire rod of the present invention, the range of the area ratio (A) of the matched precipitate changes according to the change in the Ag content. When the area ratio (A) of the matched precipitate is within the above range, a copper alloy wire having excellent tensile strength and vibration durability can be obtained even when the diameter of the wire is reduced without impairing the excellent conductivity. be able to. The above formula (I) is derived from the experimental results in which the Ag content in the copper alloy wire is selected variously.

When the area ratio (A) of the matched precipitate is less than (0.393 × x −0.589)%, the amount of the matched precipitate deposited is small, so that the matched precipitate does not hinder the deformation of the copper alloy wire. As a result, excellent tensile strength and vibration durability cannot be obtained. On the other hand, when the area ratio (A) of the matched precipitate exceeds (3.88 × x-5.81)%, the dimensions such as the length and width of the matched precipitate become large, so that the matched precipitate also becomes It does not hinder the deformation of the copper alloy wire, and as a result, excellent tensile strength and vibration durability cannot be obtained.

Since the matched precipitate is mainly composed of Ag, the area ratio (A) of the matched precipitate varies depending on the content of Ag. That is, it is considered that the area ratio (A) increases as the Ag content increases, and the area ratio (A) decreases as the Ag content decreases. When the area ratio (A) of the matched precipitate is high, the matched precipitate hinders the deformation of the copper alloy wire, and as a result, the tensile strength and the vibration durability are improved. On the other hand, it was found that even if the area ratio (A) of the matched precipitate is excessive, the matched precipitate does not hinder the deformation of the copper alloy wire, and as a result, excellent tensile strength and vibration durability cannot be obtained. did. Therefore, in the copper alloy wire rod of the present invention, by adjusting not only the range of Ag content but also the range of the area ratio (A) of the matching precipitates, excellent tensile strength and vibration are not impaired without impairing the conductivity. Achieved durability.

[Precipitation consistent with Cu in the parent phase]
In the present specification, the above-mentioned "precipitation consistent with the Cu of the matrix" means that the precipitate has a certain crystal orientation with respect to the crystal of Cu which is the matrix. means. As a method for determining whether or not the precipitate has a specific crystal orientation with respect to the Cu crystal which is the parent phase, that is, whether or not the precipitate is a matched precipitate. , There is a method of reading from the diffraction pattern.

When a sample is irradiated with an electron beam in a transmission electron microscope, electron diffraction occurs. Diffraction waves generated by the diffraction of electron beams strengthen or weaken each other depending on the crystal type, interatomic distances constituting the crystal, etc., and form a specific diffraction pattern depending on the crystal. For example, when an electron beam is incident on a Cu crystal in the [010] direction, a diffraction spot is generated at the apex of the square and its midpoint, as shown in FIG.

Since Cu and Ag have the same face-centered cubic lattice structure (fcc structure), the diffraction patterns are the same, but the spacing between the diffraction spots is different because the lattice constants are different. The larger the lattice constant, the narrower the distance between the diffraction spots. Therefore, the Ag diffraction spots appear in a narrower range than the Cu diffraction spots. Assuming that Ag precipitates are present in the Cu alloy and the crystals of Ag precipitates are aligned in a specific direction, the diffraction spots of Ag precipitates are slightly inside the diffraction spots of Cu, which is the parent phase. It will appear. When the crystal orientation of Cu and the crystal orientation of Ag are completely the same, that is, when both the Cu crystal and the Ag crystal are oriented in the [100] direction, the diffraction patterns are the same and the Ag diffraction pattern is the same. Appears slightly inside the diffraction pattern of Cu.

On the other hand, when Cu and Ag are aligned in a specific direction, but the crystal orientation of Cu and the crystal orientation of Ag do not completely match, for example, Cu with respect to the observation axis [100] direction. When the crystals of Ag are oriented in the [100] direction, but the crystals of Ag are oriented in the [110] direction, the diffraction pattern corresponding to the [100] direction of Cu and the diffraction pattern corresponding to the [110] direction of Ag. Appears.

From the above, when the diffraction pattern of Cu and the diffraction pattern of Ag are the same, and the diffraction pattern of Ag appears slightly inside the diffraction pattern of Cu, or the diffraction pattern of Cu indicating that the crystals of Cu correspond to a predetermined direction. When an Ag diffraction pattern indicating that the Ag crystals correspond to a predetermined direction appears, the Ag is "precipitated in accordance with the Cu of the matrix phase", that is, the Ag precipitate is Cu which is the matrix phase. Judge that they are consistent.

However, when Cu and Ag are not aligned at all, that is, when the crystal orientation of Cu and the crystal orientation of Ag do not match at all, it means that Ag is arranged in various crystal directions with respect to Cu. Therefore, the Ag diffraction pattern is randomly formed with respect to the Cu diffraction pattern. In this case, it is determined that the Ag precipitate is inconsistent with Cu, which is the parent phase.

[Mean width (W) of precipitates precipitated in accordance with Cu in the matrix]
The precipitates that are precipitated in accordance with the Cu of the matrix are fibrous along the longitudinal direction of the copper alloy wire, that is, fibrous extending in a direction substantially parallel to the longitudinal direction of the copper alloy wire. It is more effective when it is a substance. In the copper alloy wire rod of the present invention, when a cross section parallel to the longitudinal direction thereof is observed, the copper alloy wire rod extends in the longitudinal direction of the copper alloy wire rod precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. The average width (W) of the existing fibrous matching precipitates is not particularly limited, but the following formula (II) is used because the effect of the matching precipitates on the deformation of the copper alloy wire is further improved.
(8.3 × d) nm ≦ W ≦ (24.9 × d) nm (II)
(In the formula (II), d represents the wire diameter (mm) of the copper alloy wire), preferably within the range of (9.0 × d) nm ≦ W ≦ (24.0 × d) nm. It is particularly preferable that it is within the range of. Therefore, in a preferred embodiment of the copper alloy wire rod of the present invention, the range of the preferable average width (W) of the matched precipitate changes according to the change in the wire diameter. The above formula (II) is specified based on the wire diameter and the average width of the matched precipitate in the examples of the present application described later.

When the average width (W) of the matched precipitate is less than (8.3 × d) nm, the matched precipitate becomes thinner with respect to the wire diameter, and the effect of the matched precipitate on the deformation of the copper alloy wire is limited. There is a possibility that On the other hand, if it exceeds (24.9 × d) nm, the dimension of the average width (W) becomes larger than the wire diameter, so that the effect of matching precipitation on the deformation of the copper alloy wire can be limited. There is sex.

[Mean width (W) of precipitates precipitated in accordance with Cu in the matrix]
In the copper alloy wire rod of the present invention, when a cross section parallel to the longitudinal direction thereof is observed, the copper alloy wire rod extends in the longitudinal direction of the copper alloy wire rod precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. The average length (L) of the existing fibrous matching precipitate is not particularly limited, but the following formula (III) is used because the effect of the matching precipitate on the deformation of the copper alloy wire is further improved.
(11.3 / d) nm ≦ L ≦ (33.8 / d) nm (III)
(In the formula (III), d represents the wire diameter (mm) of the copper alloy wire), preferably within the range of (14.0 / d) nm ≦ L ≦ (30.0 / d) nm. It is particularly preferable that it is within the range of. Therefore, in a preferred embodiment of the copper alloy wire rod of the present invention, the range of the preferable average length (L) of the matched precipitate changes according to the change in the wire diameter. The above formula (III) is specified based on the wire diameter and the average length of the matched precipitate in the examples of the present application described later.

When the average length (L) of the matched precipitate is less than (11.3 / d) nm, the matched precipitate becomes shorter than the wire diameter, and the effect of the matched precipitate on the deformation of the copper alloy wire is limited. May be done. On the other hand, if it exceeds (33.8 / d) nm, the dimension of the average length (L) becomes larger than the wire diameter, so that the effect of matching precipitation on the deformation of the copper alloy wire is also limited. there is a possibility.

[Average interval (S) of precipitates precipitated in accordance with Cu in the matrix]
In the copper alloy wire rod of the present invention, when observing a cross section parallel to the longitudinal direction thereof, the average spacing of the matching precipitates that are precipitated in accordance with the Cu of the parent phase in the rectangular observation region of 240 nm × 360 nm. (S) is not particularly limited, but the following formula (IV)
(760 × x ^ -2.25) × dnm ≦ S ≦ (2300 × x ^ -2.25) × dnm (IV)
(In the formula (IV), d represents the wire diameter (mm) of the copper alloy wire, and x represents the mass% of Ag). Therefore, in a preferred embodiment of the copper alloy wire rod of the present invention, the range of the preferable average length (L) of the matched precipitate changes according to the change in the wire diameter and the Ag content. The above formula (IV) is derived from the experimental results in which the Ag content in the copper alloy wire is selected variously.

When the average spacing (S) of the matching precipitates is less than (760 × x ^ -2.25) × dnm, the spacing of the matching precipitates becomes narrower with respect to the wire diameter and Ag content, and the matching precipitates, The hindrance to deformation of copper alloy wire may be limited. On the other hand, when it exceeds (2300 × x ^ -2.25) × dnm, the interval of the matching precipitate becomes wider with respect to the wire diameter and the Ag content, and again, the matching precipitate with respect to the deformation of the copper alloy wire. Interfering effects may be limited.

[Matched precipitates are aligned in the same crystal axis direction]
Further, in the copper alloy wire rod of the present invention, it is preferable that the matched precipitates are matched in the same crystal axis direction with respect to Cu as the matrix phase. "Aligned in the same crystal axis direction" means that the crystal of Cu, which is the parent phase, and the crystal of the matched precipitate mainly composed of Ag are aligned in the same crystal axis direction. By having such a crystal arrangement, a strain is generated between the crystal of Cu which is the parent phase and the crystal of the matched precipitate. Since this strain hinders the deformation of the copper alloy wire, a higher tensile strength is imparted to the copper alloy wire.

Whether or not the matched precipitates are matched in the same crystal axis direction with respect to Cu, which is the matrix, can be determined by the following method. First, a sample copper alloy wire is thinned by a focused ion beam (FIB) method, and a predetermined observation area (for example, an observation area consisting of a rectangle of 240 nm × 360 nm) is set using a transmission electron microscope (TEM). Observe. The sample is cut out parallel to the longitudinal direction, and when TEM observation is performed, the longitudinal direction is arranged horizontally for observation.

Next, in order to confirm that the precipitates are consistently precipitated, a diffraction pattern is acquired as described above. At this time, the diffraction pattern may be incident on any crystal zone axis, and for example, an image is taken with the [110] crystal zone axis incident, which is generally easy to understand. The diffraction pattern by the crystal of Cu, which is the matrix, is observed with the highest brightness, but other diffraction patterns are also observed, and by confirming the diffraction pattern with the same diffraction pattern type as Cu and a slightly narrower spot spacing. , Confirm that the precipitates are consistently precipitated.

Next, the angle of the sample is changed to obtain a diffraction pattern by incident on the [100] or [111] crystal zone axis with respect to Cu, which is the parent phase. Check if there is a slightly narrow diffraction pattern. When it is confirmed that the diffraction patterns are the same as those of Cu in the crystal zone axis incidents on the above two axes, the matched precipitates are matched with respect to the parent phase Cu in the same crystal axis direction. Evaluate as.

[Method for manufacturing copper alloy wire rod of the present invention]
Next, the method for producing the copper alloy wire rod of the present invention will be described. The method for producing a copper alloy wire rod of the present invention includes (a) a step of melting the raw material, (b) a step of casting the melted raw material to obtain an ingot, and (c) a copper alloy material obtained from the ingot. The first heat treatment step, (d) the first heat treatment step, then the second heat treatment step, and (e) the second heat treatment copper alloy material are final wire drawing, and the degree of processing thereof. loge (A0 / A1) ^ 2 (In the formula, A0 is the cross-sectional area perpendicular to the longitudinal direction of the copper alloy material immediately before the final wire drawing process, and A1 is the longitudinal direction of the copper alloy material immediately after the final wire drawing process. It includes a step of obtaining a copper alloy wire rod by performing a final wire drawing process in which the cross-sectional area in the orthogonal direction is 2.5 or more.

The steps of (a) melting the raw material and (b) casting the melted raw material to obtain an ingot can be carried out by a known general method. The composition of the raw materials used in the step (a) is as follows: Ag is 1.5 to 6.0% by mass, Mg is 0 to 1.0% by mass, Cr is 0 to 1.0% by mass, and Zr is 0 to 0. Each component is blended in a predetermined ratio so that 1.0% by mass and the balance is Cu.

(C) The heat treatment temperature in the step of first heat-treating the copper alloy material is 700 ° C. or higher. If the temperature of the first heat treatment step is less than 700 ° C., it becomes difficult to fibrate the precipitate mainly composed of Ag during the final wire drawing process, and excellent tensile strength and vibration durability may not be obtained. The lower limit of the temperature in the first heat treatment step is preferably 750 ° C., particularly preferably 800 ° C. from the viewpoint of obtaining more excellent tensile strength. On the other hand, the upper limit of the temperature in the first heat treatment step is not particularly limited, but is preferably 900 ° C.

The heat treatment time in the first heat treatment step is not particularly limited, but is preferably 0.1 to 10 hours, particularly 0.5 to 5 hours, from the viewpoint of dispersing a large amount of precipitates and forming them into fibers in a later step. preferable.

After the first heat treatment step, the copper alloy material is cooled, and (d) further the second heat treatment is performed. The heat treatment temperature in the second heat treatment step is 350 to 600 ° C. If the heat treatment temperature in the second heat treatment step is less than 350 ° C. or higher than 600 ° C., precipitates mainly composed of Ag may not be sufficiently precipitated, and excellent tensile strength and vibration durability may not be obtained. The heat treatment time in the second heat treatment step is not particularly limited, but is preferably 0.5 to 20 hours, and particularly preferably 1.0 to 15 hours.

After the second heat treatment step, the copper alloy material is cooled to carry out (e) final wire drawing. In the final wire drawing, the degree of processing log (A0 / A1) ^ 2 (in the formula, A0 is the cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material immediately before the final wire drawing, and A1 is immediately after the final wire drawing. The cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material) is 2.5 or more. If the degree of processing of the final wire drawing is less than 2.5, the matched precipitate cannot be sufficiently stretched and made into fibers, and excellent tensile strength and vibration durability may not be obtained.

The degree of processing of the final wire drawing may be 2.5 or more from the viewpoint of sufficiently stretching and fiberizing the matched precipitate, and the higher the degree of processing, the better the tensile strength. Therefore, the upper limit of the degree of processing of the final wire drawing is not particularly limited.

Further, if necessary, between (b) the step of obtaining the ingot and (c) the first heat treatment step, and / or (c) between the first heat treatment step and (d) the second heat treatment step, Intermediate wire drawing may be applied. The degree of processing of intermediate wire drawing is not particularly limited, but from the viewpoint of increasing the degree of processing in final wire drawing, the degree of processing loge (B0 / B1) ^ 2 (in the formula, B0 is copper immediately before intermediate drawing. It is preferable that the cross-sectional area in the direction orthogonal to the longitudinal direction of the alloy material and B1 is the cross-sectional area in the direction perpendicular to the longitudinal direction of the copper alloy material immediately after the intermediate wire drawing process) are low, but the matching precipitate is sufficiently precipitated. In order to sufficiently extend and fiberize the matched precipitate in the final wire drawing process, it is preferable that the intermediate wire drawing process has a high degree of processing. From the above, the degree of processing is preferably 0 to 1.0 from the viewpoint of the balance between the two.

The copper alloy wire rod of the present invention is particularly subjected to the above-mentioned (c) first heat treatment step and (d) second heat treatment step, even when the diameter of the wire rod is reduced without impairing excellent conductivity. A copper alloy wire having excellent tensile strength can be manufactured.

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-40
Raw materials (oxygen-free copper, silver, magnesium, chromium and zirconium) were put into a graphite crucible so as to have the alloy composition shown in Table 1 below, and the temperature inside the crucible was heated to 1250 ° C. or higher to melt the raw materials. A resistance heating type heating furnace was used for melting. The atmosphere inside the crucible was a nitrogen atmosphere so that oxygen would not be mixed into the molten copper. Further, after keeping the temperature at 1250 ° C. or higher for 3 hours or longer, the cooling rate was set to 500 to 1000 ° C./s, and an ingot having a diameter (φ) of about 10 mm was cast with a graphite mold. After the start of casting, continuous casting was performed by appropriately adding the above raw materials. When chromium was contained in the raw material (Examples 23, 27, 28, 31, 33 and 34), the temperature inside the crucible was maintained at 1600 ° C. or higher to dissolve the raw material.

Next, the ingot obtained as described above was subjected to the first heat treatment at the temperature and time shown in Table 1 below. After the first heat treatment step, the test material was subjected to intermediate wire drawing to φ8 mm, and further, the second heat treatment was carried out at the temperature and time shown in Table 1 below. After the second heat treatment step, the final wire drawing process was performed to the wire diameter shown in Table 1 below at a predetermined processing degree to obtain a copper alloy wire rod. The first heat treatment and the second heat treatment were performed in a batch furnace in a nitrogen atmosphere.

Comparative Examples 1 to 7
In Comparative Examples 1, 4 to 7, ingots having a size of about 8 mm were cast, and the final wire drawing was performed to φ0.1 mm without intermediate wire drawing. Obtained a copper alloy wire in the same process as in the above-mentioned Example and under the production conditions shown in Table 1 below. In Comparative Example 2, a copper alloy wire rod was obtained in the same steps as in Comparative Examples 1 and 4 to 7, except that the first heat treatment and the second heat treatment were not performed. Further, in Comparative Example 3, a copper alloy wire rod was obtained in the same steps as in Comparative Examples 1 and 4 to 7 except that the second heat treatment was not performed. Therefore, in Comparative Example 3, the first heat treatment was performed at φ8 mm.

[Method of observing precipitates that are consistent with the Cu of the matrix phase]
The copper alloy wire rods in Examples and Comparative Examples are made into a thin film by the FIB method, and are composed of a rectangle having a cross-sectional direction (short direction) length of 240 nm x a longitudinal direction length of 360 nm using a transmission electron microscope (TEM). The observation area was observed. The copper alloy wire was cut out parallel to the longitudinal direction, and when TEM observation was performed, the longitudinal direction was arranged horizontally for observation. Next, a diffraction pattern was acquired in order to confirm that the precipitates were consistently precipitated. At this time, the diffraction pattern was imaged at the [110] crystal zone axis incident where the pattern is generally easy to understand. The diffraction pattern by the crystal of Cu, which is the matrix, is observed with the highest brightness, but other diffraction patterns are also observed, and the precipitate of the diffraction pattern is Ag by measuring the type of the diffraction pattern and the spot interval. Was identified.

Next, when only the diffracted wave of the diffraction pattern of the precipitate obtained above is selected and observed with an objective aperture so that it can be observed, a portion (that is, a matched precipitate) that generates a diffracted wave forming the diffraction pattern is observed. ) Is brightly observed. This is called a dark-field image, and this dark-field image (shown in FIG. 2) was imaged for the copper alloy wire rods in Examples and Comparative Examples. From the dark-field image obtained above, the area ratio, average width, average length, and average interval of the precipitates (matched precipitates) that are consistently precipitated in the parent phase Cu are obtained as follows. It was.

First, the contrast obtained in the dark field image was binarized. The p-tile method was used for binarization. When the p-tile method is used, the threshold value is determined without changing the order of brightness, so that photographs taken in the same range in different observation environments can be binarized in almost the same manner. However, it is premised that the environment does not change the brightness in the local part on the image. After that, the number of pixels of the white contrast portion, that is, the matching precipitate (matched precipitate) is calculated with respect to the total number of pixels of the obtained photograph, and the total number of pixels of the matched precipitate is calculated. The area ratio was calculated by dividing by.

Further, the number of pixels of the matching precipitate in the longitudinal direction was calculated with the cross-sectional direction of the dark field image as the row number, and the number of pixels for each row was graphed as shown in FIG. Lines 0 to 275 observed in FIG. 3 correspond to a length of 240 nm in the cross-sectional direction. The part where the number of pixels is 25 or more is regarded as one peak, the half width of each peak is defined as the width of the matching precipitate, the width of the matching precipitate is obtained from each peak, the average value is calculated, and the average width is calculated. And said. The maximum value of the peak was defined as the length of the matched precipitate, the length of the matched precipitate was obtained from the number of pixels of each peak with respect to the total number of pixels in the photograph, and the average value was calculated to obtain the average length. The interval between the maximum value of the above peak and the maximum value of the adjacent peak is measured, each interval is defined as the interval of matched precipitates, each peak interval is obtained, the average value is calculated, and the average interval of precipitates is used. did.

In each of the above aspects of the matched precipitate, the sample thickness of the thin film was calculated with 0.15 μm as a reference thickness. If the thickness of the copper alloy wire is different from the standard thickness, the thickness of the copper alloy wire is converted to the standard thickness, that is, the dispersion calculated based on the photograph taken (standard thickness / copper alloy wire thickness). The dispersion density can be calculated by multiplying by the density. In Examples and Comparative Examples, the sample thickness was set to about 0.15 μm for all copper alloy wires by the FIB method.

[Evaluation method for evaluating that the matched precipitates are matched in the same crystal axis direction with respect to the parent phase Cu]
As described above, in order to confirm that the precipitates are consistently precipitated, a method of acquiring a diffraction pattern by incident on the [110] crystal zone axis with respect to Cu as the matrix, and Cu as the matrix. In order to confirm that the matched precipitates are aligned in the same crystal axis direction, the angle of the sample is changed and the Cu as the parent phase is diffracted by [110] or [111] crystal zone axis incident. According to the procedure of the method for acquiring the pattern, it is evaluated whether or not the matched precipitates are matched with respect to the parent phase Cu in the same crystal axis direction. Table 1 shows the matching with respect to the parent phase Cu. If the precipitates are aligned in the same crystal axis direction, they are marked with ◯, and if they are not aligned, they are marked with x.

[Measurement method of tensile strength]
A tensile test was performed using a precision universal testing machine (manufactured by Shimadzu Corporation) in accordance with JIS Z2241 to determine the tensile strength (MPa). The above test was carried out for each of the three copper alloy wires, and the average value (N = 3) was obtained and used as the tensile strength of each copper alloy wire.

[Measurement method of conductivity]
The conductivity was calculated by measuring the specific resistance of three 300 mm long test pieces in a constant temperature bath maintained at 20 ° C (± 0.5 ° C) using the four-terminal method, and calculating the average conductivity. .. The distance between the terminals was 200 mm.

As shown in Table 1 above, the first heat treatment step at 700 ° C. or higher and the second heat treatment step at 350 to 600 ° C. were performed, and the area ratio of the matched precipitate was (0.393 × x −0.589)% ≦ A. In Examples 1 to 40 in which ≦ (3.88 × x-5.81)% (x represents mass% of Ag in the formula), the wire rod was 0.02 mm without impairing excellent conductivity. Even when the diameter was reduced to ~ 2.6 mm, a copper alloy wire having excellent tensile strength could be obtained.

On the other hand, in Comparative Example 1 in which 8.0% by mass of Ag was added, the conductivity was remarkably lowered. Further, Comparative Example 2 in which the first heat treatment step and the second heat treatment step were not performed has the same production conditions as in Comparative Example 2 and the same composition as in Comparative Example 2 except that the first heat treatment step and the second heat treatment step were performed. As compared with Example 4, no matched precipitate was obtained, and good tensile strength could not be obtained. Further, in Comparative Example 3 in which the second heat treatment step was not performed, Comparative Examples 4 and 6 in which the temperature of the second heat treatment step was as low as 300 ° C., and Comparative Examples 5 and 7 in which the temperature of the second heat treatment step was as high as 700 ° C. However, no matched precipitate was obtained, and good tensile strength could not be obtained.

[1] Contains 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr and 0 to 1.0% by mass of Zr, and the balance is A copper alloy wire having an alloy composition consisting of Cu and unavoidable impurities.
When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the area ratio (A) of the precipitates precipitated in accordance with the Cu of the matrix in the rectangular observation area of 240 nm × 360 nm is
The following formula (I)
(0.393 x x-0.589)% ≤ A ≤ (3.88 x x-5.81)% (I)
(In formula (I), x represents the mass% of Ag.)
Copper alloy wire that is within the range of.
[2] The copper alloy wire rod according to [1], wherein the total content of at least one component selected from the group consisting of Mg, Cr and Zr is 0.01 to 3.0% by mass.
[3] The copper alloy wire rod according to [1] or [2], wherein the precipitate that is deposited in accordance with the Cu of the parent phase exists in a fibrous form along the longitudinal direction of the copper alloy wire rod.
[4] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average width of the precipitates precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. (W) is
The following formula (II)
(8.3 × d) nm ≦ W ≦ (24.9 × d) nm (II)
(In formula (II), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to [3], which is within the range of.
[5] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average length of the precipitates precipitated in accordance with the Cu of the parent phase in a rectangular observation area of 240 nm × 360 nm. (L) is
The following formula (III)
(11.3 / d) nm ≦ L ≦ (33.8 / d) nm (III)
(In formula (III), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to [3] or [4], which is within the range of.
[6] When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average spacing of the precipitates precipitated in accordance with the Cu of the matrix in a rectangular observation area of 240 nm × 360 nm. (S) is
The following formula (IV)
(760 × x ^ -2.25) × dnm ≦ S ≦ (2300 × x ^ -2.25) × dnm (IV)
(In formula (IV), d represents the wire diameter (mm) of the copper alloy wire, and x represents the mass% of Ag.)
The copper alloy wire rod according to any one of [3] to [5], which is within the range of.
[7] The copper alloy wire rod according to any one of [1] to [6], wherein the precipitate is aligned in the same crystal axis direction with respect to Cu of the parent phase.
[8] A step of melting the raw material, a step of casting the melted raw material to obtain an ingot, a step of first heat-treating the copper alloy material obtained from the ingot, and a step of further performing a second heat treatment. The method for producing a copper alloy wire according to any one of [1] to [7], which comprises a step of finally drawing the copper alloy material subjected to the second heat treatment to obtain a copper alloy wire. hand,
The first heat treatment step is performed at a temperature of 700 ° C. or higher.
The second heat treatment step is performed at a temperature of 350 to 600 ° C.
Process degree log (A0 / A1 ) of the final wire drawing process (In the formula, A0 is the cross-sectional area in the direction perpendicular to the longitudinal direction of the copper alloy material immediately before the final wire drawing, and A1 is the copper immediately after the final wire drawing. A method for manufacturing a copper alloy wire having a cross-sectional area of 2.5 or more in the direction orthogonal to the longitudinal direction of the alloy material.
[9] The wire drawing process is performed between the step of obtaining the ingot and the first heat treatment step, and / or between the first heat treatment step and the second heat treatment step. Manufacturing method of copper alloy wire rod.

When the average width (W) of the matched precipitate is less than (8.3 × d) nm, the matched precipitate becomes thinner with respect to the wire diameter, and the effect of the matched precipitate on the deformation of the copper alloy wire is limited. There is a possibility that On the other hand, in (24.9 × d) nm greater, since the size of the average width (W) relative to the diameter increases again, hindered effect is limited matched precipitates to deformation of the copper alloy wire there is a possibility.

When the average length (L) of the matched precipitate is less than (11.3 / d) nm, the matched precipitate becomes shorter than the wire diameter, and the effect of the matched precipitate on the deformation of the copper alloy wire is limited. May be done. On the other hand, in (33.8 / d) nm greater, since the size of the average length with respect to diameter (L) increases, again, hindered effect is limited matched precipitates to deformation of the copper alloy wire There is a possibility that

[Average interval (S) of precipitates precipitated in accordance with Cu in the matrix]
In the copper alloy wire rod of the present invention, when observing a cross section parallel to the longitudinal direction thereof, the average spacing of the matching precipitates that are precipitated in accordance with the Cu of the parent phase in the rectangular observation region of 240 nm × 360 nm. (S) is not particularly limited, but the following formula (IV)
(760 × x ^ -2.25) × dnm ≦ S ≦ (2300 × x ^ -2.25) × dnm (IV)
(In the formula (IV), d represents the wire diameter (mm) of the copper alloy wire, and x represents the mass% of Ag). Therefore, in a preferred embodiment of the copper alloy wire rod of the present invention, the range of the preferable average interval (S) of the matched precipitates also changes according to the change in the wire diameter and the Ag content. The above formula (IV) is derived from the experimental results in which the Ag content in the copper alloy wire is selected variously.

[Method for manufacturing copper alloy wire rod of the present invention]
Next, the method for producing the copper alloy wire rod of the present invention will be described. The method for producing a copper alloy wire rod of the present invention includes (a) a step of melting the raw material, (b) a step of casting the melted raw material to obtain an ingot, and (c) a copper alloy material obtained from the ingot. The first heat treatment step, (d) the first heat treatment step, then the second heat treatment step, and (e) the second heat treatment copper alloy material are final wire drawing, and the degree of processing thereof. loge (A0 / A1 ) (In the formula, A0 is the cross-sectional area perpendicular to the longitudinal direction of the copper alloy material immediately before the final wire drawing process, and A1 is the direction orthogonal to the longitudinal direction of the copper alloy material immediately after the final wire drawing process. A step of obtaining a copper alloy wire rod by performing a final wire drawing process in which the cross-sectional area) is 2.5 or more is included.

After the second heat treatment step, the copper alloy material is cooled to carry out (e) final wire drawing. In the final wire drawing, the degree of processing log (A0 / A1 ) (in the formula, A0 is the cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material immediately before the final wire drawing, and A1 is the copper alloy immediately after the final wire drawing. The cross-sectional area in the direction orthogonal to the longitudinal direction of the material) is 2.5 or more. If the degree of processing of the final wire drawing is less than 2.5, the matched precipitate cannot be sufficiently stretched and made into fibers, and excellent tensile strength and vibration durability may not be obtained.

Further, if necessary, between (b) the step of obtaining the ingot and (c) the first heat treatment step, and / or (c) between the first heat treatment step and (d) the second heat treatment step, Intermediate wire drawing may be applied. The degree of processing of intermediate wire drawing is not particularly limited, but from the viewpoint of increasing the degree of processing in final wire drawing, the degree of processing loge (B0 / B1 ) (in the formula, B0 is a copper alloy material immediately before intermediate drawing. It is preferable that the cross-sectional area in the direction orthogonal to the longitudinal direction of the above and B1 is the cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material immediately after the intermediate wire drawing process), but the matching precipitate is sufficiently precipitated and finally. In order to sufficiently extend and fiberize the matched precipitate in the wire drawing process, it is preferable that the intermediate wire drawing process has a high degree of processing. From the above, the degree of processing is preferably 0 to 1.0 from the viewpoint of the balance between the two.

Claims (9)

It contains 1.5 to 6.0% by mass of Ag, 0 to 1.0% by mass of Mg, 0 to 1.0% by mass of Cr and 0 to 1.0% by mass of Zr, and the balance is Cu and unavoidable. A copper alloy wire having an alloy composition composed of impurities.
When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the area ratio (A) of the precipitates precipitated in accordance with the Cu of the matrix in the rectangular observation area of 240 nm × 360 nm is
The following formula (I)
(0.393 x x-0.589)% ≤ A ≤ (3.88 x x-5.81)% (I)
(In formula (I), x represents the mass% of Ag.)
Copper alloy wire that is within the range of. The copper alloy wire rod according to claim 1, wherein the total content of at least one component selected from the group consisting of Mg, Cr and Zr is 0.01 to 3.0% by mass. The copper alloy wire rod according to claim 1 or 2, wherein the precipitate that is deposited in accordance with the Cu of the parent phase exists in a fibrous form along the longitudinal direction of the copper alloy wire rod. When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average width (W) of the precipitates precipitated in accordance with the Cu of the matrix in a rectangular observation region of 240 nm × 360 nm. But,
The following formula (II)
(8.3 × d) nm ≦ W ≦ (24.9 × d) nm (II)
(In formula (II), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to claim 3, which is within the range of. When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average length (L) of the precipitate deposited in accordance with the Cu of the matrix in the rectangular observation region of 240 nm × 360 nm. )But,
The following formula (III)
(11.3 / d) nm ≦ L ≦ (33.8 / d) nm (III)
(In formula (III), d represents the wire diameter (mm) of the copper alloy wire.)
The copper alloy wire rod according to claim 3 or 4, which is within the scope of. When observing a cross section parallel to the longitudinal direction of the copper alloy wire, the average spacing (S) of the precipitates precipitated in a rectangular observation region of 240 nm × 360 nm in accordance with the Cu of the parent phase. But,
The following formula (IV)
(760 × x ^ -2.25) × dnm ≦ S ≦ (2300 × x ^ -2.25) × dnm (IV)
(In formula (IV), d represents the wire diameter (mm) of the copper alloy wire, and x represents the mass% of Ag.)
The copper alloy wire rod according to any one of claims 3 to 5, which is within the range of. The copper alloy wire rod according to any one of claims 1 to 6, wherein the precipitates are aligned in the same crystal axis direction with respect to Cu as the parent phase. A step of melting the raw material, a step of casting the melted raw material to obtain an ingot, a step of first heat-treating the copper alloy material obtained from the ingot, a step of further heat-treating the second, and the first step. (2) The method for producing a copper alloy wire according to any one of claims 1 to 7, further comprising a step of finally drawing a heat-treated copper alloy to obtain a copper alloy wire.
The first heat treatment step is performed at a temperature of 700 ° C. or higher.
The second heat treatment step is performed at a temperature of 350 to 600 ° C.
Process degree log (A0 / A1) ^ 2 (in the formula, A0 is the cross-sectional area in the direction orthogonal to the longitudinal direction of the copper alloy material immediately before the final wire drawing process, and A1 is immediately after the final wire drawing process. A method for manufacturing a copper alloy wire rod having a cross-sectional area of 2.5 or more in the direction orthogonal to the longitudinal direction of the copper alloy material. The copper alloy according to claim 8, wherein wire drawing is performed between the step of obtaining the ingot and the first heat treatment step, and / or between the first heat treatment step and the second heat treatment step. Method of manufacturing wire rod.

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