JP2013057121A - Method of manufacturing soft dilute copper alloy material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a high conductive soft-dilute-copper-alloy material that has high tensile strength and high elongation percentage even though it is a soft material and whose manufacturing steps are simple and low cost.SOLUTION: The method of manufacturing a soft-dilute-copper-alloy material includes plastic working of a soft-dilute-copper-alloy containing an additional element selected from a group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn and Cr, and the balance copper and inevitable impurity, and a subsequent annealing treatment of the soft-dilute-copper-alloy. A working ratio in the plastic working before the annealing treatment is not less than 50%.

Description

The present invention relates to a method for producing a novel soft dilute copper alloy material having high electrical conductivity and having high tensile strength and elongation even in a soft material.

In recent science and technology, electricity is used in all parts, such as power as a power source and electrical signals. In the field of cables, lead wires, electronic parts, etc. to transmit them, bonding wires, etc. Conductor wire is used. As a material used for the conductive wire, a metal having a relatively high conductivity such as copper, silver, or gold is used. In particular, a copper wire is often used in consideration of cost.

The copper and lump can be broadly divided into hard copper and soft copper according to the molecular arrangement. And the kind of copper which has a desired property according to the utilization purpose is used.

Hard lead wires are often used for lead wires for electronic parts. For example, cables used in electronic devices such as medical devices, industrial robots, and notebook computers are combined with severe bending, twisting, and tension. Since it is used in an environment where repeated external force is repeatedly applied, rigid hard copper wire is not suitable, and soft copper wire is used.

Conductive wires used for such applications are required to have contradictory properties such as good conductivity (high conductivity), good tensile strength, elongation, bending properties, and low hardness. To date, copper materials that maintain high electrical conductivity, tensile strength, and elongation have been developed.

For example, the invention according to Patent Document 1 is an invention related to a conductor for a bending-resistant cable having good tensile strength, elongation rate, and electrical conductivity. In particular, oxygen-free copper having a purity of 99.99 mass% or more has a purity of 9
0.99 mass% or more of indium 0.05 to 0.70 mass%, purity 99.9 m
It describes a conductor for a bending-resistant cable in which a copper alloy containing P of ass% or more in a concentration range of 0.0001 to 0.003 mass% is formed on a wire.

Further, in the invention according to Patent Document 2, indium is 0.1 to 1.0 mass% and boron is 0.
. It describes a flex-resistant copper alloy wire having a content of 01 to 0.1 mass% and the balance being copper.

Patent Document 3 proposes a conductor with reduced tensile strength and elongation in addition to good tensile strength and elongation for bonding wire use, such as 99.999mas.
It describes a conductor that has both high tensile strength and elongation, and softness by adjusting the amount of impurities in high-purity copper of s% or more.

JP 2002-363668 A Japanese Patent Laid-Open No. 9-256084 Japanese Patent Laid-Open No. 61-224443

However, the invention according to Patent Document 1 is an invention related to a hard copper wire with a large content of In as an additive element, and no investigation has been made on a soft copper wire excellent in tensile strength and elongation. Moreover, since there is much content of In as an additive element, electroconductivity will fall.

Moreover, although the invention which concerns on patent document 2 is invention regarding a soft copper wire, since the addition amount of an additional element is large similarly to the invention which concerns on patent document 1, electroconductivity will fall.

On the other hand, it is conceivable to secure high conductivity by selecting a highly conductive copper material such as oxygen-free copper (OFC) as a copper material as a raw material. However, when this oxygen-free copper (OFC) is used as a raw material and it is used without adding other elements in order to maintain conductivity, oxygen-free copper can be obtained by increasing the degree of processing of the copper rough drawing wire. It is conceivable to achieve both high tensile strength and elongation by making the crystal structure inside the wire finer, and it is suitable for use as a hard wire by work hardening by wire drawing, but cannot be applied to soft wire. There is a problem.

Since the invention according to Patent Document 3 is based on high-purity copper of 99.999 mass% or higher, it is predicted that high conductivity will be obtained. However, high-purity copper is obtained by a zone melting method or a vacuum beam melting method. Therefore, the manufacturing process becomes complicated and the material has to be expensive.

An object of the present invention is to provide a method for producing a soft dilute copper alloy material that has high conductivity, has a high tensile strength and elongation even in a soft material, and has a simple and inexpensive manufacturing process. .

The present invention is plastic to a soft dilute copper alloy containing an additive element selected from the group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr, the balance being copper and inevitable impurities A method for producing a soft dilute copper alloy material that is processed and then annealed, wherein the degree of processing in the plastic processing before the annealing is 50% or more.

In the method for producing a soft diluted copper alloy material of the present invention, the annealing treatment is performed at a temperature of 250 ° C to 800 ° C.
In addition, it is performed continuously while passing through the tubular furnace in the range of 0.6 second to 10.0 seconds, and is performed by the current annealing in the range of current supply voltage 21 V to 35 V and travel speed 100 m / min to 600 m / min. The soft dilute copper alloy is 2 to 12 mass ppm sulfur, more than 2 mass ppm and not more than 30 mass ppm oxygen; It is preferable to contain 4-55 mass ppm of Ti as an additive element.

The soft dilute copper alloy material according to the present invention has a conductivity of 98% IACS (universal standard soft copper (Inter
national Announce Copper Standard) resistivity 1.7241 ×
(Conductivity with 10 ⁻⁸ Ωm as 100%), 100% IACS, and preferably a soft dilute copper alloy material as a soft copper material that satisfies 102% IACS. As a secondary matter, use of an SCR continuous casting and rolling facility that has few surface scratches, a wide manufacturing range, and enables stable production, and a processing degree of 90% for wire rods (for example, φ8 mm → φ2).
. 6 mm) is preferably formed using a material having a softening temperature of 148 ° C. or lower.

In order to obtain a copper wire rod that satisfies the softening temperature and electrical conductivity after cold wire drawing, it is preferable that sulfur in copper is crystallized and precipitated by the following (a) and (b).

(A) It is preferable to add titanium by increasing the oxygen concentration of the material to an amount exceeding 2 mass ppm. Thus, first, in molten copper, TiS and titanium oxide (TiO ₂ ) or Ti—O
-S particles are believed to be formed.

(B) Next, by setting the aging rolling temperature to 880 to 550 ° C., which is set lower than the normal copper production conditions of 950 to 600 ° C., dislocations are introduced into the copper, and S is likely to precipitate. It is preferable to do so. As a result, S precipitates on the dislocations or precipitates with the titanium oxide (TiO ₂ ) as a nucleus, and as an example, Ti—O—S particles and the like are formed as in the case of molten copper.

(1) Additive elements The reason why elements selected from the group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr are selected as the additive elements is that these elements are combined with other elements. This is because it is an easily active element and can be easily trapped with sulfur (S), so that S can be trapped, the copper base material of the matrix can be highly purified, and the hardness of the material can be reduced. Moreover, the effect that high electroconductivity is realizable by trapping S is also acquired. One type or two or more types of additive elements are included. Also, other elements and impurities that do not adversely affect the properties of the alloy can be included in the alloy.

As an additive element, the total content of one or more of Ti, Ca, V, Ni, Mn and Cr is 4 to 55 mass ppm, more preferably 10 to 20 mass ppm.
The content of g is 2 to 30 mass ppm, more preferably 5 to 10 mass ppm, and Zr
, Nb content is preferably 8 to 100 mass ppm, more preferably 20 to 40 mass ppm.

In a preferred embodiment to be described later, the oxygen content exceeds 2 mass ppm and is preferably 30 mass ppm or less, more preferably 5 to 15 mass ppm. Depending on the addition amount of the additive element and the sulfur content, In the range having the properties of
More than s ppm and 400 mass ppm can be included.

  The content of sulfur is preferably 3 to 12 mass ppm, more preferably 3 to 8 mass ppm.

When obtaining a soft copper alloy material having a conductivity of 98% IACS or higher, pure copper containing inevitable impurities
(Base material) is 3-12 mass ppm sulfur and more than 2 mass ppm 30m
A wire rod (rough drawing wire) is manufactured with a soft dilute copper alloy material containing oxygen of less than as ppm and Ti of 4 to 55 mass ppm. More than 2mass ppm and 30mass
In this embodiment, since oxygen is contained in ppm or less, so-called low oxygen copper (L
OC).

Here, in order to obtain a soft copper alloy material having an electrical conductivity of 100% IACS or more, 2 to 12 mass ppm of sulfur is added to pure copper containing inevitable impurities, and the mass exceeds 2 mass ppm to 30 m.
A wire rod is preferably made of a soft dilute copper alloy material containing oxygen of not more than ppm and Ti of 4 to 37 mass ppm.

Furthermore, when obtaining a soft copper alloy material having an electrical conductivity of 102% IACS or higher, pure copper containing inevitable impurities is added to 3 to 12 mass ppm of sulfur and more than 2 mass ppm to 30 mass.
The wire rod is preferably made of soft dilute copper alloy material containing oxygen of s ppm or less and Ti of 4 to 25 mass ppm.

Usually, in the industrial production of pure copper, sulfur is taken into copper when producing electrolytic copper, so it is difficult to make sulfur 3 mass ppm or less. The upper limit of the sulfur concentration of general-purpose electrolytic copper is 12 mass ppm.

As described above, if the amount of oxygen to be controlled is small, it is difficult to lower the softening temperature.
An amount exceeding pm is preferred. Moreover, when there is too much oxygen, it becomes easy to produce a surface flaw in a hot rolling process, so it is preferable to set it to 30 mass ppm or less.

(2) About dispersed substances It is desirable that the size of dispersed particles be small and distributed. The reason is that the size is small and the number is large because it functions as a sulfur deposition site.

Usually, sulfur and titanium form compounds or aggregates in the form of TiO, TiO ₂ , TiS, and Ti—O—S, and the remaining Ti and S are present in the form of a solid solution. TiO size is 20
0 nm or less, TiO ₂ is 1000 nm or less, TiS is 200 nm or less, Ti—O—S is 3
A soft dilute copper alloy material distributed in crystal grains at 00 nm or less is used. “Crystal grains” means the crystal structure of copper.

However, since the size of the formed particles changes depending on the holding time of the molten copper during casting and the cooling condition, it is necessary to set casting conditions.

(3) Continuous casting and rolling conditions Wire rods are manufactured with an ingot rod working degree of 90% (30 mm) to 99.8% (5 mm) by the SCR continuous casting and rolling method (South Continuous Rod System). As an example, a method of making a φ8 mm wire rod with a processing degree of 99.3% is used.

(A) The molten copper temperature in the melting furnace is desirably 1100 ° C. or higher and 1320 ° C. or lower. When the temperature of the molten copper is high, blowholes increase, scratches are generated, and the particle size tends to increase. The reason why the temperature is set to 1100 ° C. or higher is that copper is likely to solidify and the production is not stable, but the casting temperature is preferably as low as possible.

(B) As for the hot rolling temperature, the temperature at the first rolling roll is preferably 880 ° C. or lower, and the temperature at the final rolling roll is preferably 550 ° C. or higher.

Unlike normal pure copper production conditions, crystallization of sulfur in molten copper and precipitation of sulfur during hot rolling are the subject of the present invention, so in order to reduce the solid solubility limit that is the driving force. The molten copper temperature and the hot rolling temperature are preferably (a) and (b).

The normal hot rolling temperature is such that the temperature at the first rolling roll is 950 ° C. or lower and the temperature at the final rolling roll is 600 ° C. or higher. In order to reduce the solid solution limit, It is desirable to set the temperature at 880 ° C. or lower and the temperature at the final rolling roll at 550 ° C. or higher.

Under such conditions, the conductivity of a wire rod having a diameter of φ8 mm is preferably 98% IACS or more, 100% IACS, or more preferably 102% IACS or more, and softening of the wire (for example, φ2.6 mm) after cold drawing. A soft dilute copper alloy wire or plate-like material having a temperature of 130 ° C. to 148 ° C. can be obtained.

In order to use industrially, the soft copper wire of the purity used industrially manufactured from electrolytic copper is used.
8% IACS or more is necessary, and the softening temperature is 148 ° C. or less in view of its industrial value.
When Ti is not added, the temperature is 160 to 165 ° C. The softening temperature of high purity copper (6N) is 12
Since it was 7-130 degreeC, a limit value shall be 130 degreeC from the acquired data. This slight difference is in the presence of inevitable impurities not found in high purity copper (6N).

The conductivity is about 101.7% IACS at the level of oxygen-free copper, and 102.8% IACS for high-purity copper (6N), so that the conductivity is as close as possible to high-purity copper (6N). Is desirable.

Since the copper in the base material is melted in the shaft furnace, the copper oxide is mixed in and the particle size is increased and the quality is lowered. Therefore, after the melting, the copper is controlled so that it is in a reduced state, that is, reducing gas (CO). A method of stably producing a wire rod that is cast and rolled under the atmosphere by controlling the sulfur concentration, Ti concentration, and oxygen concentration of the constituent elements of the dilute alloy is preferable.

As described above, the soft diluted copper alloy material manufactured by the manufacturing method of the present invention can obtain a practical soft diluted copper alloy material excellent in electrical conductivity, softening temperature, and surface quality. Wire, plate, foil), enameled wire, soft pure copper, high conductivity copper, soft copper wire and energy during annealing can be reduced, so that high productivity can be obtained.

Moreover, the soft diluted copper alloy material manufactured by the manufacturing method of this invention may form a plating layer on the surface. As the plating layer, for example, a layer mainly composed of tin, nickel, silver, zinc, and palladium is applicable, and so-called Pb-free plating may be used.

Moreover, the soft diluted copper alloy material manufactured by the manufacturing method of the present invention can be used as a soft diluted copper alloy stranded wire obtained by twisting a plurality of wires into a wire.

Moreover, the soft diluted copper alloy material manufactured by the manufacturing method of this invention can also be used as a cable which provided the insulating layer around them by setting it as a wire or a twisted wire.

In addition, the soft diluted copper alloy material manufactured by the manufacturing method of the present invention is formed by twisting a plurality of wires into a central conductor, forming an insulator coating on the outer periphery of the central conductor, and forming an insulator coating on the outer periphery of the insulator coating. It can also be used as a coaxial cable in which an outer conductor made of copper or a copper alloy is arranged and a jacket layer is provided on the outer periphery thereof. Further, a plurality of coaxial cables can be arranged in the shield layer and used as a composite cable in which a sheath is provided on the outer periphery of the shield layer.

Moreover, the use of the soft dilute copper alloy material manufactured by the manufacturing method of the present invention is wide, such as a copper plate used for a heat sink, a deformed copper material used for a lead frame, a copper foil used for a wiring board, etc. It can be adapted to the application.

Applications of the soft dilute copper alloy material of the present invention include, for example, wiring materials for consumer solar cells, conductors for enameled wires for motors, soft copper materials for high temperatures used at 200 ° C to 700 ° C, conductors for power cables, and signal wires It can be used as a conductor, a molten solder plating material that does not require annealing, a wiring conductor for FPC, a copper material excellent in heat conduction, and a high-purity copper replacement material. The shape is not particularly limited, and may be a conductor having a round cross section, a rod-shaped conductor, or a flat conductor.

In addition, as an example of the method for producing the soft dilute copper alloy material of the present invention, the wire rod was produced by the SCR continuous casting rolling method, and the soft material was produced by hot rolling. Or you may make it manufacture by the propel type continuous casting rolling method.

(4) About degree of work and annealing method of soft dilute copper alloy material In order to obtain a desired crystal structure, the method for producing soft dilute copper alloy material of the present invention has a degree of work in plastic working before annealing heat treatment. 50% or more. Here, the degree of processing can be defined as follows.

Degree of processing (%) = [cross-sectional area before drawing (soft material) −cross-sectional area after drawing] × 100
/ [Cross sectional area before drawing (soft material)]

The reason for this is that when a material with a workability of less than 50% is annealed, in the process of recrystallization,
This is because the strain energy for generating a large number of crystal nuclei is not sufficient, and only a small number of crystal nuclei exist, and a coarse crystal tends to be formed when the crystal grows. A more preferable degree of processing is 80 to 99.8%.

The method for producing a soft dilute copper alloy material of the present invention performs cold drawing of a soft dilute copper alloy in a plurality of stages, and each time the processing is performed, the processing degree is set to 50% or more. An annealing process is performed.

The soft dilute copper alloy material obtained by the production method of the present invention preferably has an average crystal grain size of 20 μm or less from the surface to the inside thereof until the depth of 20% of the wire diameter or plate thickness.

As an annealing method for obtaining a desired crystal structure using a material subjected to plastic working, a diameter of 1
For linear shapes less than mm, continuous annealing through a tubular furnace can be applied at temperatures of 250 ° C. to 550 ° C. and times of 0.6 seconds to 5.0 seconds. This is because the temperature is 2
This is because when the temperature is lower than 50 ° C. or when the time is shorter than 0.6 seconds, the material still has a processed structure and the elongation value is small. Conversely, the temperature exceeds 550 ° C or 5
. When longer than 0 seconds, the crystal grains are coarsened and the desired crystal structure or elongation cannot be obtained.
Or it is because there exists a possibility that the conductor softened excessively may deform | transform by the tension | tensile_strength at the time of winding.

In the case of a linear shape with a diameter of 1 mm or more, a temperature of 300 ° C. to 800 ° C. and a time of 1.0 second
Continuous annealing through a tubular furnace in the range of 10.0 seconds can be applied.

As another annealing method, batch-type annealing can be applied at a temperature of 150 ° C. to 550 ° C. and a range of 3 hours or less in a linear shape having a diameter of less than 1 mm. As a feature of batch type annealing, it is possible to perform a large amount of processing by one annealing work by using a large capacity annealing furnace,
It is effective for annealing thin conductors with a small volume per unit length. The reason for selecting this annealing condition is that, as described above, when the temperature is lower than 150 ° C., the softening is not sufficient and the elongation value is low. Conversely, if the temperature exceeds 550 ° C. or longer than 3 hours, the crystal grains become coarse and the desired crystal structure cannot be obtained, or the elongation rate is low, or defects such as adhesion between lines occur. This is because it may be easy to do.

In the case of a linear shape having a diameter of 1 mm or more, batch-type annealing can be applied within a temperature range of 170 ° C. to 700 ° C. and 3 hours or less.

As the lower limit of the annealing time, in order to obtain a desired crystal structure and soften the material,
0.5 hr or more is desirable.

As another annealing method, in the case of a line shape having a diameter of less than 1 mm, continuous treatment with an energization annealer is also possible in the range of energization voltages of 21 V to 33 V and travel speeds of 300 m / min to 600 m / min. Annealing with a current-carrying annealer can be softened at a high production rate, which can contribute to high-efficiency production, that is, cost reduction. The reason for selecting this annealing condition is that when the energized voltage is less than 20 V or the traveling speed exceeds 600 m / min, the softening is not sufficient and the elongation value is low. Conversely, the energizing voltage is 30V
If it exceeds 300 m or less than 300 m / min, the crystal grains become coarse and the desired crystal structure cannot be obtained, or the elongation is small, or the conductor may be deformed or disconnected due to excessive thermal energy.

In the case of a linear shape having a diameter of 1 mm or more, the energization voltage is 25 V to 35 V and the traveling speed is 10
In the range of 0 m / min to 500 m / min, continuous treatment with energization annealing is also possible.

Moreover, it is desirable that these annealing be performed in an inert gas such as nitrogen gas or argon gas in order to prevent oxidation of the copper alloy material.

(5) Crystal structure of soft dilute copper alloy material The soft dilute copper alloy material according to the present invention has a crystal structure of at most 20 with respect to the wire diameter or plate thickness from the surface of the wire or plate toward the inside of the copper conductor. % Average grain size up to 20% depth
The surface layer contains m or less crystal grains, and the average crystal grain size inside thereof is larger than the average crystal grain size of the surface layer.

This is because the presence of fine crystals, particularly fine crystals on the surface layer, can be expected to improve the tensile strength and elongation of the material. The reason for this is that the local strain introduced near the grain boundary due to tensile deformation becomes smaller as the crystal grain size becomes finer, which contributes to the relaxation of the grain boundary stress concentration. This is because it is considered that the grain boundary destruction is suppressed.

According to the present invention, a method for producing a soft dilute copper alloy material of a soft dilute copper alloy material having high electrical conductivity, having a high tensile strength and elongation even in a soft material, and having a simple and inexpensive manufacturing process. Is to provide.

It is a figure which shows the relationship between the annealing temperature of the implementation material 1 and the comparison material 1, and elongation rate. It is a figure by the photograph of the cross-sectional structure | tissue of the radial direction of the implementation material 1 in the annealing temperature of 500 degreeC. It is a figure by the photograph which shows the cross-sectional structure | tissue of the radial direction of the implementation material 1 in the annealing temperature of 700 degreeC. 3 is a photograph showing a cross-sectional structure in the radial direction of the comparative material 1. FIG. It is a figure which shows the outline of a bending fatigue test. 5 is a graph obtained by measuring a bending life showing a relationship between a surface bending strain and the number of bendings in Comparative Material 2 and Example Material 2. 5 is a photograph showing a cross-sectional structure in the width direction of an implementation material 2. FIG. It is a figure by the photograph which shows the cross-sectional structure | tissue of the width direction of the sample of the comparative material 2. FIG. 6 is a graph obtained by measuring a bending life showing a relationship between a surface bending strain and the number of bendings in Comparative Material 3 and Example Material 3. FIG. 4 is a photograph view showing a cross-sectional structure in the width direction of the working material 3. It is a figure by the photograph which shows the cross-sectional structure | tissue of the width direction of the comparative material. It is a figure which shows the outline of the measuring method of the average grain size in the surface layer of a sample. It is a figure which shows the relationship between the tensile strength of the implementation material 4 and the comparison material 4, and elongation rate. It is a figure which shows the relationship between the elongation of the implementation material 4 and the comparison material 4, and hardness. It is a figure which shows the relationship between the tensile strength of the implementation material 4 and the comparison material 4, and hardness. FIG. 6 is a photograph view showing a cross-sectional structure in the width direction of the working material 4. It is a figure by the photograph which shows the cross-sectional structure | tissue of the width direction of the comparative material. It is a schematic diagram of the measuring method of the average grain size in a surface layer.

Hereinafter, although embodiment of this invention is described, embodiment described below does not limit the invention based on a claim. In addition, it should be noted that not all combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention.

Experimental example

(Production of soft dilute copper alloy material according to the present invention)
As an experimental material, φ8 mm copper wire (wire rod, degree of processing 99.3%) having a titanium concentration of 13 mass ppm in low oxygen copper (oxygen concentration: 7 mass ppm to 8 mass ppm, sulfur concentration: 5 mass ppm) was prepared. The φ8 mm copper wire is hot rolled by SCR continuous forging. Ti flows the molten copper melted in the shaft furnace into the reed in the reducing gas atmosphere, guides the molten copper flowing in the reed to the casting pot of the same reducing gas atmosphere, and after adding Ti in this casting pot, An ingot rod was made with a mold formed between the cast ring and the endless belt through the nozzle. This ingot rod is hot-rolled and φ8mm
The copper wire was created. Next, cold drawing was applied to each experimental material. As a result, φ
A 2.6 mm-sized copper wire (copper bonding wire, processing degree: 89.4%) was produced.

Using the copper wire of φ2.6 mm size, first, the characteristics of the material used for the copper bonding wire were verified.

(Soft properties of soft dilute copper alloy materials)
Table 1 uses as a sample a comparative material 1 using an oxygen-free copper wire and an embodiment material 1 using a soft dilute copper alloy wire containing 13 mass ppm Ti in low-oxygen copper, with different annealing temperatures for 1 hour. It is the table | surface which verified Vickers hardness (Hv) of what gave annealing.

As shown in Table 1, when the annealing temperature is 400 ° C., the Vickers hardness (Hv) of the comparative material 1 and the working material 1 is equivalent, and even when the annealing temperature is 600 ° C., the equivalent Vickers hardness (Hv
). From this, the soft dilute copper alloy wire according to the present invention has sufficient soft properties, and also has excellent soft properties even in the region where the annealing temperature exceeds 400 ° C., even when compared with the oxygen-free copper wire. I understand that.

[Resistance and bending life of soft dilute copper alloy wire]
Table 2 shows that the comparison material 1 using an oxygen-free copper wire and the annealing material for 1 hour at different annealing temperatures of the embodiment material 1 using a soft dilute copper alloy wire containing 13 mass ppm Ti in low oxygen copper were applied. It is the table | surface which verified the transition of 0.2% proof stress value. As a sample, a 2.6 mm diameter sample was used.

As shown in Table 2, when the annealing temperature is 400 ° C., the 0.2% proof stress values of the comparative material 1 and the implementation material 1 are equivalent, and at the annealing temperature of 600 ° C., the implementation material 1 and the comparison material 1 are almost equivalent. It can be seen that the 0.2% proof stress value is.

[Relationship between elongation characteristics and crystal structure of soft dilute copper alloy wire]
FIG. 1 shows comparison material 1 using an oxygen-free copper wire with a diameter of 2.6 mm and low-oxygen copper with a diameter of 2.6 mm.
It is the graph which verified the transition of the value of elongation (%) of what performed annealing for 1 hour at different annealing temperature of execution material 1 using soft dilute copper alloy wire containing mass ppm Ti. The circle symbol shown in FIG. 1 indicates the working material 1, and the square symbol indicates the comparative material 1.

As shown in FIG. 1, the working material 1 exceeds the annealing temperature of 100 ° C. and 130 as compared with the comparative material 1.
It can be seen that excellent elongation characteristics are exhibited in a wide range from about 900C to 900C.

FIG. 2 is a view showing a cross-sectional photograph of the copper wire of Example 1 at an annealing temperature of 500 ° C. FIG.
As shown in FIG. 4, a fine crystal structure is formed in the entire cross section of the copper alloy wire, and this fine crystal structure is considered to contribute to the elongation characteristics. On the other hand, the cross-sectional structure of the comparative material 1 at an annealing temperature of 500 ° C. has undergone secondary recrystallization, and the crystal grains in the cross-sectional structure are coarser than the crystal structure of FIG. Is thought to have been reduced.

FIG. 3 is a view showing a cross-sectional photograph of the copper wire of Example 1 at an annealing temperature of 700 ° C. It can be seen that the crystal grain size of the surface layer in the cross section of the copper alloy wire is extremely smaller than the crystal grain size inside. Although the internal recrystallization of the crystal structure is progressing,
The fine crystal grain layer in the outer layer remains. Although the material 1 of the execution material 1 grows greatly in the internal crystal structure, it seems that the fine crystal layer remains on the surface layer, and thus maintains high elongation characteristics.

FIG. 4 is a cross-sectional photograph showing a cross-sectional structure of the comparative material 1. In Comparative Material 1, crystal grains having substantially the same size are arranged uniformly from the surface to the center, and secondary recrystallization proceeds in the entire cross-sectional structure. It is considered that the elongation characteristics in the above high temperature region are deteriorated.

As described above, the working material 1 is superior to the comparative material 1 in terms of elongation characteristics, so that it is excellent in handleability when manufacturing a stranded wire using this conductor, excellent in bending resistance, and easy to bend. Also in this point, there is an advantage that the cable arrangement becomes easy.

Next, the soft dilute copper alloy material according to the present invention is required to have a long bending life, but the soft dilute copper in which 13 mass ppm of Ti is added to the comparative material 2 using low oxygen copper and low oxygen copper is required. The bending life of Example 2 using an alloy wire was measured. Here, as a sample, 0.26 m
The wire material of m diameter was annealed at 400 ° C. for 1 hour, the comparative material 2 has the same component composition as the comparative material 1, and the working material 2 has the same component composition as the working material 1. I used one.

FIG. 5 shows a method for measuring the bending life, and a bending fatigue test was conducted by this method. The bending fatigue test is a test in which a load is applied and repeated bending strain of tension and compression is applied to the sample surface.
The sample is set between bending jigs (denoted as rings in the figure) as shown in (A), and the jig is rotated 90 degrees as shown in (B) while applying a load to bend. By this operation, a compressive strain is applied to the surface of the wire rod in contact with the bending jig, and a tensile strain is applied to the opposite surface correspondingly. Thereafter, the state returns to the state (A) again. Next, it is rotated 90 degrees in the direction opposite to the direction shown in FIG. Also in this case, a compressive strain is applied to the surface of the wire rod in contact with the bending jig, and a corresponding tensile strain is applied to the opposite surface, resulting in a state (C). And (C
) To return to the initial state (A). This bending fatigue cycle 1 (A) → (B) → (A) → (C
) → (A) takes 4 seconds. The surface bending strain can be obtained by the following equation.

Surface bending strain (%) = r / (R + r) × 100 (%)
{R: Wire bending radius (30 mm), r = wire radius}

FIG. 6 shows a comparative material 2 using an oxygen-free copper wire after annealing at 400 ° C. for 1 hour,
It is a figure which shows the relationship between the surface bending distortion and the frequency | count of bending which measured the bending life in the implementation material 2 using the soft dilute copper alloy wire which added Ti to low oxygen copper. As shown in FIG. 6, the working material 2 according to the present invention has a surface bending strain of 0.45%, and the number of bendings is 4 as compared with the comparative material 2 slightly less than 2000 times.
The bending life was a little over 000 times and twice as long.

FIG. 7 is a view showing the cross-sectional structure showing the crystal structure in the width direction of the embodiment material 2 with a photograph. FIG. 8 is a view showing the cross-sectional structure showing the crystal structure in the width direction of the comparative material 2 with a photograph. is there. The implementation material 2 is the same component as the implementation material 1 and is a 0.26 mm diameter wire with the highest soft material conductivity.
It is fabricated through an annealing process for 1 hour at an annealing temperature of 400 ° C. Comparative material 2 is oxygen-free copper (O
FC), and a 0.26 mm diameter wire rod is manufactured through an annealing treatment at an annealing temperature of 400 ° C. for 1 hour.

  Table 3 shows the conductivity of Example Material 2 and Comparative Material 2.

As shown in Table 3, the working material 2 is less obstructed by the flow of electrons when the current is passed as compared with the comparative material 2, and the electrical resistance is reduced. Therefore, the implementation material 2 has a higher conductivity (% IACS) than the comparison material 2.

As shown in FIG. 8, it can be seen that the crystal structure of the comparative material 2 has uniform crystal grains having the same overall size from the surface portion to the center portion. On the other hand, as shown in FIG. 7, the crystal structure of the embodiment material 2 has a difference in crystal grain size between the surface layer and the inside, and the inside crystal grain size is extremely larger than the crystal grain size in the surface layer. It has become.

The implementation material 2 supplements, for example, S in the copper of the conductor processed so as to have φ2.6 mm and φ0.26 mm in the form of Ti—S and Ti—O—S. The oxygen contained in the copper (O), for example, as TiO _2, is present in the form of TixOy, the crystal grains are precipitated in the grain boundaries.

For this reason, when copper is annealed and the crystal structure is recrystallized, the recrystallized material of Example 2 is likely to proceed and the internal crystal grains grow greatly. For this reason, compared with the comparative material 2, the implementation material 2 progresses with less obstruction of the flow of electrons when a current is passed, and the electrical resistance is reduced. Therefore, the implementation material 2 has higher conductivity (% IACS) than the comparison material 2.

Based on the above results, the product using the embodiment material 2 is soft, has improved conductivity, and can improve bending characteristics. In the conventional conductor, a high-temperature annealing process is required to recrystallize the crystal structure to the size of the embodiment material 2. However, if the annealing temperature is too high,
S is dissolved again. Further, the conventional conductor has a problem that when it is recrystallized, it becomes soft and the bending property is lowered. In the execution material 2, since it can be recrystallized without being twinned when annealed, the internal crystal grains become large and soft, but on the other hand, since the fine crystals remain in the surface layer, the bending characteristics do not deteriorate. .

FIG. 9 shows a comparative material 3 using an oxygen-free copper wire after annealing at 600 ° C. for 1 hour,
It is a figure which shows the relationship between the surface bending distortion and the frequency | count of bending showing the result of having measured the bending life in the implementation material 3 using the soft dilute copper alloy wire which added Ti to low oxygen copper. Here, as a sample, a 0.26 mm diameter wire was annealed at an annealing temperature of 600 ° C. for 1 hour,
The comparative material 3 has the same component composition as that of the comparative material 1, and the example material 3 also has the same component composition as that of the example material 1. The measuring method of the bending life was performed under the same conditions as the measuring method of FIG.

As shown in FIG. 9, also in this case, the embodiment material 3 according to the present invention has a surface bending strain of 0.45% and the number of bendings is less than 2000 times compared to 1000 times of the comparative material 3, but about The bending life was twice as high. As a result, under the annealing conditions, the execution materials 2 and 3 were compared with the comparison material 2,
It is understood that this is due to the fact that the 0.2% proof stress value was larger than that of 3.

FIG. 10 is a photograph showing a cross-sectional structure showing the crystal structure in the width direction of the embodiment material 3,
FIG. 11 is a view showing a cross-sectional structure showing the crystal structure in the width direction of the comparative material 3 by a photograph. As shown in FIGS. 10 and 11, it can be seen that the crystal structure of the comparative material 3 has uniform crystal grains of the same size from the surface portion to the central portion. On the other hand, the crystal structure of the embodiment material 3 has a sparse crystal grain size as a whole, and it should be noted that the crystal grain size in the layer formed thin near the surface in the cross-sectional direction of the sample is internal. It is extremely small compared to the crystal grain size.

The inventors consider that the fine crystal grain layer that is not formed in the comparative material 3 and appears on the surface layer of the working material 3 contributes to the improvement of the bending characteristics of the working material 3.

If this is normal, if the annealing process is performed for 1 hour at an annealing temperature of 600 ° C., the comparative material 3
It is understood that crystal grains uniformly coarsened by recrystallization are formed,
In the case of the present invention, even if the annealing process is performed at an annealing temperature of 600 ° C. for 1 hour, a fine crystal grain layer still remains on the surface layer. It is thought that a soft dilute copper alloy material was obtained.

Based on the cross-sectional photographs of the crystal structure shown in FIG. 10 and FIG. 11, the average crystal grain size in the surface layer of the samples of Example Material 3 and Comparative Material 3 was measured.

FIG. 12 shows a method for measuring the average grain size in the surface layer. As shown in FIG.
. The average value in the surface layer was obtained by averaging the measured values of the crystal grain size in the range on the line of 1 mm in length from the surface of the cross section in the width direction of 26 mm diameter to the depth of 50 μm at 10 μm intervals in the depth direction. The grain size was used.

As a result of the measurement, the average crystal grain size in the surface layer of Comparative Material 3 was 50 μm, whereas the average crystal grain size in the surface layer of Example Material 3 was greatly different in that it was 10 μm. It is thought that the fineness of the average crystal grain size of the surface layer suppresses the progress of cracks in the bending fatigue test and extends the bending fatigue life. That is, if the crystal grain size is large, cracks propagate along the grain boundaries, but if the crystal grain size is small, the direction of crack growth changes,
The progress is suppressed, and this is considered to have caused a great difference in the bending characteristics between the comparative material 3 and the working material 3 as described above.

Further, the average crystal grain size in the surface layer of the embodiment material 1 having the diameter of 2.6 mm described above and the comparative material 1 is a length of 50 μm in the depth direction from the surface of the cross section in the width direction of 2.6 mm diameter. The crystal grain size in the range of 10 mm was measured. As a result of the measurement, the average crystal grain size in the surface layer of Comparative Material 1 was 100 μm, whereas the average crystal grain size in the surface layer of Example Material 1 was 20 μm. As an effect of the present invention, the upper limit value of the average grain size of the surface layer is preferably 20 μm or less, and a value of 5 μm or more is assumed from the manufacturing limit value.

(Manufacture of soft dilute copper alloy materials)
The process up to producing a copper wire of φ2.6 mm size is the same as that of the embodiment 1 of the soft dilute copper alloy material. This was subjected to wire drawing to φ0.9 mm, once annealed with a current-carrying annealer, and then drawn to φ0.05 mm. The degree of processing from φ2.6 mm to φ0.9 mm is 88.0%.

The material of φ0.05 mm was subjected to continuous annealing with an energization annealer at an energization voltage of 21 to 33 V and a winding speed of 500 m / min. As a comparison, φ0.05
Oxygen-free copper of mm (purity 99.99% or more, OFC) was also produced under the same heat treatment conditions and used as the material for comparative material 4. In this case, the wire drawing degree from φ0.9 mm to φ0.05 mm is 99.
7%.

As another annealing method, a soft dilute copper alloy material drawn from φ0.9 mm to φ0.05 mm is subjected to running annealing at 400 ° C. to 600 ° C. × 0.8 to 4.8 seconds in a tubular furnace as described above. The material of the application material 4 was used. As a comparison, φ0.05mm oxygen-free copper (99.99% or more, O
FC) was also produced under the same thermomechanical processing conditions and used as the material for Comparative Material 4.

The mechanical properties (tensile strength, elongation), hardness, and crystal grain size of these materials were measured. The average grain size in the surface layer is 10 in the depth direction from the surface of the cross section in the width direction of 0.05 mm diameter.
The crystal grain size in the range of 0.25 mm length at a depth of μm was measured.

(Soft properties, elongation and tensile strength of soft dilute copper alloy materials)
FIG. 13 shows a wire rod according to the comparative material 1 using an oxygen-free copper wire, and 13 mass for low-oxygen copper.
About the wire rod which concerns on the implementation material 1 produced from the soft dilute copper alloy wire containing s ppm Ti, it wire-draws from φ0.9mm (annealing material) to φ0.05mm, and anneals by an electric annealing ( It is a figure which shows the result of the implementation material 4 and the comparative material 4 which measured the relationship between the tensile strength and elongation rate after performing voltage 21-33V and winding-up speed 500m / min.

As shown in FIG. 13, it can be seen that the tensile strength of the working material 4 is 15 MPa or more larger than that of the comparative material 4 when compared at substantially the same elongation rate. Compared with oxygen-free copper, the tensile strength can be increased without reducing the elongation. For example, the soft dilute copper alloy wire of the embodiment material 4 has a stress higher than that of a conductor using oxygen-free copper. The occurrence of disconnection due to the addition can be reduced.

FIG. 14 shows a wire rod according to the comparative material 4 using an oxygen-free copper wire, and 13 mass for low-oxygen copper.
About the wire rod which concerns on the implementation material 4 produced from the soft dilute copper alloy wire containing s ppm Ti, it wire-draws from (phi) 0.9mm (annealing material) to (phi) 0.05mm, and it is run annealing by a tubular furnace Cross-sectional hardness after (temperature 300 ° C-600 ° C, time 0.8-4.8 seconds)
It is a figure which shows the relationship between Hv) and a mechanical characteristic (elongation rate).

The cross section hardness was evaluated by polishing the cross section of a φ0.05 mm wire embedded in the resin and measuring the Vickers hardness at the center of the wire. The number of measurements was n = 5, and the average value was used.

Tensile strength and elongation were measured using a 0.05 mm wire with a gauge distance of 100 mm and a tensile speed of 2
Evaluation was performed by conducting a tensile test under the condition of 0 mm / min. The maximum tensile stress when the material breaks is the tensile strength, and the maximum amount of deformation (strain) when the material breaks is defined as the elongation percentage.

As shown in FIG. 14, when compared at substantially the same elongation rate, it can be seen that the hardness of the working material 4 is about 10 Hv smaller than that of the comparative material 4. Compared with oxygen-free copper, the hardness can be reduced without deteriorating the elongation characteristics. For example, the soft dilute copper alloy material of the embodiment material 4 is bonded to the bonding wire using oxygen-free copper. The pad damage at the time can be reduced.

Table 4 shows the results of extracting and comparing data of conditions under which the hardness is substantially the same between the embodiment material 4 and the comparative material 4 among the evaluation results shown in FIG. The implementation material 4 is a wire rod according to the implementation material 1 which is drawn from φ0.9 mm (annealing material) to φ0.05 mm, and the inside of the tubular furnace is 400 ° C. ×
The mechanical properties and hardness when running annealed for 1.2 seconds are shown. Similarly, the comparative material 4 is obtained when the wire rod according to the comparative material 1 is drawn from φ0.9 mm (annealed material) to φ0.05 mm and annealed at 600 ° C. for 2.4 seconds in a tubular furnace. It shows the mechanical properties and hardness.

As shown in Table 4, even when the materials have the same hardness, the elongation percentage of the implementation material 4 is 7% or more higher than that of the comparative material 4, so that, for example, when used as a bonding wire, It can greatly contribute to the improvement of connection reliability and handling characteristics. Moreover, since the tensile strength is higher than that of a bonding wire using oxygen-free copper while having the same hardness, it can greatly contribute to the strength reliability of the connecting portion (ball neck portion).

Here, the connection reliability of the wire bonding portion is resistance to stress generated by a difference in thermal expansion between the copper wire and the resin material after resin molding after wire bonding.

The handling property means resistance to stress when a wire is supplied from the wire spool to the bonding portion, and other difficulty in winding.

FIG. 15 is a diagram showing the relationship between hardness (Hv) and tensile strength. As shown in FIG. 15, it can be seen that the hardness of the working material 4 is about 10 Hv smaller than that of the comparative material 4 when compared with substantially the same tensile strength. Since the hardness can be reduced without reducing the tensile strength, for example, when the soft diluted copper alloy material of the embodiment material 4 is used as a bonding wire, pad damage during bonding can be reduced.

Table 5 shows the results of extracting and comparing the data under conditions in which the tensile strength is almost equal between the working material 4 and the comparative material 4. The execution material 4 is obtained when the wire rod according to the implementation material 1 is drawn from φ0.9 mm (annealing material) to φ0.05 mm, and the tube furnace is annealed at 500 ° C. for 4.8 seconds. It shows the mechanical properties and hardness. Similarly, the comparative material 4 is obtained when the wire rod according to the comparative material 1 is drawn from φ0.9 mm (annealed material) to φ0.05 mm and annealed at 600 ° C. for 2.4 seconds in a tubular furnace. It shows the mechanical properties and hardness.

As shown in Table 5, even when the materials have the same tensile strength, the elongation of the implementation material 4 is 5% higher than that of the comparison material 4, so that, for example, when used as a bonding wire, connection during wire bonding It can greatly contribute to the improvement of reliability and handling characteristics. In addition, although the material has the same tensile strength, the hardness of the working material 4 is sufficiently smaller than that of the comparative material 4, so that pad damage during wire bonding can be reduced.

The connection reliability and handling property of the wire bonding part here are the same as described above.

The balance of tensile strength, elongation and hardness is slightly different depending on the product,
As an example, according to the present invention, when stressing the tensile strength, the tensile strength is 270 MPa or more,
When a conductor with an elongation of 7% or more can be supplied, and when the importance of small hardness is emphasized, 210 MPa
It is possible to supply a conductor having a hardness of 270 MPa, an elongation of 15% or more, and a hardness of 65 Hv or less.

(Crystal structure of soft dilute copper alloy wire)
FIG. 16 is a view showing a cross-sectional structure in the width direction according to the embodiment material 4 with a photograph, and FIG. 17 is a view showing a cross-sectional structure in the width direction according to the comparative material 4 with a photograph. FIGS. 16A and 16B are at different places.

As shown in FIG. 17, it can be seen that the crystal structure of the comparative material 4 has uniform crystal grains of uniform size as a whole from the surface portion to the center portion. On the other hand, the crystal structure of the embodiment material 4 has a sparse crystal grain size as a whole, and the crystal grain size in the layer formed thin near the surface in the cross-sectional direction of the sample is smaller than the internal crystal grain size. It is extremely small.

The present inventors contribute to the fact that the fine crystal grain layer appearing on the surface layer of the embodiment material 4 that is not formed in the comparison material 4 has the soft characteristics of the embodiment material 4 and has both tensile strength and elongation characteristics. I believe that.

In general, it is understood that when heat treatment for softening is performed, crystal grains uniformly coarsened by recrystallization are formed as in the comparative material 4. However, in this embodiment, even if an annealing process for forming coarse crystal grains inside is performed, a fine crystal grain layer remains on the surface layer. Therefore, in the present Example, it is thought that the soft dilute copper alloy material excellent in tensile strength and elongation was obtained though it was a soft copper material.

Based on the cross-sectional photographs of the crystal structure shown in FIGS. 16 and 17, the average crystal grain size in the surface layer according to the example material 4 and the comparative material 4 was measured.

FIG. 18 is a diagram showing an outline of a method for measuring the average crystal grain size in the surface layer. As shown in FIG. 18, the crystal grain size was measured in a range on the line of 0.25 mm length from the surface of the cross section in the width direction of 0.05 mm diameter to the depth of 10 μm at intervals of 5 μm in the depth direction. And the average value was calculated | required from each measured value (actually measured value), and this average value was made into the average crystal grain size.

As a result of the measurement, the average crystal grain size in the surface layer of the comparative material 4 was 22 μm, whereas the average crystal grain size in the surface layer of the example material 4 was 7 μm in FIG. 16A and FIG.
) Was 15 μm and different. It is considered that high tensile strength and elongation were obtained, for one reason that the average grain size of the surface layer was fine. When the crystal grain size is large, cracks develop along the crystal grain boundary. However, if the crystal grain size is small, the growth direction of the cracks changes, so that the growth is suppressed. From this, it is considered that the fatigue characteristics of the working material 4 are superior to those of the comparative material 4. The fatigue characteristics indicate the number of stress application cycles or time until the material breaks when subjected to repeated stress.

In order to achieve the effect of the present embodiment, the average crystal grain size of the surface layer is preferably 15 μm or less.

(Tube furnace, energization annealer and batch processing of soft dilute copper alloy material of φ0.05mm)
Tables 6 to 8 show the degree of processing and heat treatment conditions of a soft dilute copper alloy material having a diameter of 0.05 mm, the presence of fine crystals on the surface layer that contribute to the improvement of tensile strength and elongation, and bending properties as described above, and elongation. The result evaluated about a rate and hardness is shown. The process up to the production of a φ0.9 mm copper wire is the same as that of the embodiment 1 of the soft dilute copper alloy material described above.

Table 6 shows the final wire diameters obtained by running annealing with a tubular furnace, and the average crystal grain size and elongation rate of the surface layer with respect to temperature and time at that time are evaluated.

Table 7 shows the final wire diameters that were annealed by energization annealing, and evaluated the average crystal grain size of the surface layer and the cross-sectional hardness of the conductor with respect to the energization voltage and running speed at that time.

The degree of processing of the samples used for the evaluations in Tables 6 and 7 is such that the final wire diameter is φ0.05 mm.
Adjustment was performed by performing annealing treatment at several intermediate wire diameter sizes in the middle of machining from φ0.9 mm annealing material.

The value of the elongation rate is an evaluation by conducting a tensile test, and an elongation rate of 15% or more passes (○).
, Less than 10 to 15% is insufficient (Δ), and less than 10% is unsuitable (x). The evaluation of the hardness was performed by performing a Vickers hardness test on the cross section of the material embedded in the resin, and 80Hv or less was accepted (O), and a material exceeding 80Hv was unsuitable (X).

The average crystal grain size of the surface layer was measured by the method shown in FIG. 18, and each measured value (actual value)
The average value was determined from the above, and 15 μm or less was determined to be acceptable (◯), and exceeding 15 μm was unsuitable (×).

Table 8 shows the final wire diameter when batch annealing is performed, and the average crystal size and elongation of the surface layer with respect to temperature and time at that time are evaluated.

The degree of processing of the samples used for the evaluation in Table 8 is such that the final wire diameter is φ0.25 mm and φ0.9 mm.
It adjusted by performing the annealing process by some intermediate | middle wire diameter sizes in the middle of the process from the annealing material of mm.

The average grain size of the surface layer was measured by the same method as in Tables 6 and 7, and the elongation value was evaluated by conducting a tensile test. ~ 18%
When less than 13%, it was considered unsuitable (x).

(Running annealing with a tubular furnace)
According to the result of running annealing with the tubular furnace shown in Table 6, it can be seen that even if the heat treatment conditions are the same, if the degree of processing is different, the size of the crystal grains in the surface layer is affected. Examples 1 to 1 in Table 6
As shown in FIG. 2, when the degree of work is 50% or more, fine crystals for improving the tensile strength, the elongation rate, and the bending property can be formed, and the elongation property is also obtained. on the other hand,
As shown in Comparative Examples 1 to 7, when the degree of processing is less than 50%, the average crystal grain of the surface layer cannot be made fine. Moreover, a high elongation rate cannot be obtained in part with it.
This is because when the degree of work is less than 50%, the strain energy for forming a large number of recrystallization nuclei is insufficient, and a small number of crystal grains grow coarsely.

Regarding the heat treatment conditions, if the temperature is 250 ° C. or more and 550 ° C. or less and the time is 0.6 seconds or more and 5.0 seconds or less, the crystal grain size is fine and the elongation is excellent.

On the other hand, when the heat treatment temperature is less than 250 ° C. or more than 550 ° C., or when the heat treatment time is 0.5 seconds or less or more than 5.0 seconds, a fine crystal grain size and a high elongation can be obtained. Can not. This is because when the temperature is less than 250 ° C. or the time is 0.5 seconds or less, the recrystallization is not sufficient and the processed structure exists, and conversely, the temperature exceeds 550 ° C. or the time is 5.0. This is because when the time exceeds 2 seconds, the crystal becomes coarse due to excessive heat and the elongation rate also decreases.

(Annealing with energized annealing)
According to the annealing performed by energization annealing shown in Table 7, it can be seen that a soft conductor with a fine crystal grain size in the surface layer can be produced in the voltage range of 21V to 33V among the heat treatment conditions. On the other hand, if the voltage is less than 21V or exceeds 33V,
It was found that those characteristics could not be obtained. This is presumably because when the voltage is lower than 21 V, the thermal energy for sufficiently releasing the strain due to the processing effect is insufficient. Conversely, when heat treatment was performed at a voltage exceeding 33 V, the material was blown out due to excessive resistance heat generation.

Regarding the running speed, it was found that a soft conductor having a fine crystal grain size on the surface layer can be produced at a speed of 300 to 600 m / min. On the other hand, traveling speed is 300m / min
It has been found that these characteristics cannot be obtained when it is smaller than 600 m / min. This is because when the speed is lower than 300 m / min, the thermal energy is excessive and the crystal is coarsened, and when it exceeds 600 m / min, the thermal energy for softening cannot be sufficiently provided. it is conceivable that.

(Batch type annealing)
According to the batch-type annealing in Table 8, the heat treatment temperature is 150 ° C. or higher.
When the temperature was set to 550 ° C. or lower, the crystal grain size of the surface layer was reduced and excellent elongation could be obtained. On the other hand, when the temperature was 120 ° C. or lower or 560 ° C. or higher, the above characteristics could not be obtained. This is because when the temperature is 120 ° C. or lower, recrystallization is not sufficient and a processed structure exists, and when it is 560 ° C. or higher, the crystal is coarsened by excessive heat. .

With respect to the heat treatment time, when it was within 3 hours, the crystal grain size of the surface layer was made small and an excellent elongation rate could be obtained. On the other hand, when the time exceeded 3 hours, the above characteristics could not be obtained. This is because if the time exceeds 3 hours, the crystal grains become coarse due to excessive thermal energy. In the case of the batch type, since processing in a short time is difficult, 0.5 time is appropriate as the lower limit of the heat treatment time.

From the above results, as a method for producing the soft dilute copper alloy material of the present invention, when the workability is 50% or more and the wire diameter is less than 1.0 mm, the annealing treatment condition is a temperature of 250 ° C. ~ 5
It is desirable to perform continuous annealing through a tubular furnace at 50 ° C. and a time of 0.6 seconds to 5.0 seconds.

Moreover, as another form, the conditions of annealing treatment are energization voltage 21V-33V, and traveling speed is 30.
It is desirable to perform continuous annealing with a current-carrying annealer at 0 m / min to 600 m / min.

Moreover, as another form, it is desirable to carry out by the batch type annealing of the conditions of a blunt process at the temperature of 150 to 550 degreeC, and 3 hours or less.

(Tube furnace, energizing annealer and batch processing of soft dilute copper alloy material of φ2.6mm)
In Tables 9 to 11, in order to confirm the influence of the wire diameter, the degree of processing of the material, the heat treatment conditions, the presence of fine crystals of the surface layer contributing to the improvement of the tensile strength and elongation, and the bending properties, the elongation, The result evaluated about is shown. The process up to the production of a copper wire of φ2.6 mm size is the same as the experimental example of the soft dilute copper alloy material described above.

The degree of processing of the samples used for the evaluations in Tables 9 and 10 is that the final wire diameter is φ2.6 mm, and the intermediate wire diameters during the processing from φ8.0 mm cast material are annealed. Adjustments were made by performing processing.

Table 9 shows the final wire diameter, which was obtained by running annealing with a tubular furnace, and evaluated the average grain size and elongation rate of the surface layer with respect to temperature and time at that time.

Table 10 shows the final wire diameters that were annealed by energization annealing, and evaluated the average crystal grain size of the surface layer and the cross-sectional hardness of the conductor with respect to the energization voltage and running speed at that time.

Table 11 shows the final wire diameter, which was annealed by batch annealing, and evaluated the average crystal grain size of the surface layer and the cross-sectional hardness of the conductor with respect to the temperature and the heating and holding time at that time.

The average crystal grain size of the surface layer was measured by the method shown in FIG.
The average value was obtained from the above, and the average crystal grain size was determined to be 20 μm or less as acceptable (◯), and unacceptable (x) when exceeding 20 μm.

The value of the elongation rate is an evaluation by conducting a tensile test, and an elongation rate of 18% or more passes (○).
, 13 to less than 18% was deemed insufficient (Δ), and less than 13% was deemed inappropriate (x). The evaluation of the hardness was performed by performing a Vickers hardness test on the cross section of the material embedded in the resin, and 80Hv or less was accepted (O), and a material exceeding 80Hv was unsuitable (X).

As shown in Tables 9 to 11, it can be seen that even if the heat treatment conditions are the same, if the degree of processing is different, the crystal grain size of the surface layer is affected. As shown in the examples, in any of the heat treatment methods, if the degree of work is 50% or more, fine crystals for improving the tensile strength, the elongation rate, and the bending property can be formed. Have both. On the other hand, as shown in the comparative example, when the degree of processing is less than 50%, the average crystal grain of the surface layer cannot be made fine. Moreover, a high elongation rate cannot be obtained in part with it.

(Annealing with tubular furnace)
Regarding the heat treatment conditions, in the annealing by the tubular furnace shown in Table 9, the temperature is 300 ° C. or higher and 800 ° C.
If the temperature is not higher than ° C. and the time is not less than 1.0 seconds and not more than 10.0 seconds, the crystal grain size is also fine and excellent in elongation.

On the other hand, when the heat treatment temperature is less than 300 ° C. or over 820 ° C., or when the heat treatment time is 0.5 seconds or less or over 10.0 seconds, it is impossible to obtain fine crystal grain size and high elongation. . This is because when the temperature is less than 300 ° C. or when the time is 0.5 seconds or less, recrystallization is not sufficient and a processed structure exists, and conversely, the temperature exceeds 820 ° C. or the time is 10. This is because when the time exceeds 0 seconds, the crystal becomes coarse due to excessive heat, and the elongation also decreases.

(Annealing with energized annealing)
It can be seen that the annealing with the current-carrying annealer shown in Table 10 can produce a soft conductor with a fine crystal grain size in the surface layer within the voltage range of 25 to 35 V among the heat treatment conditions. On the other hand, when the voltage is smaller than 21V or exceeds 35V, it has been found that those characteristics cannot be obtained. This is presumably because when the voltage is lower than 21 V, the thermal energy for sufficiently releasing the strain due to the processing effect is insufficient. Conversely, when heat treatment was performed at a voltage exceeding 35 V, the crystals became coarse due to excessive resistance heat generation.

Regarding the running speed, it was found that a soft conductor with a fine crystal grain size on the surface layer can be produced between 100 and 500 m / min. On the other hand, it has been found that when the traveling speed is lower than 80 m / min or exceeds 700 m / min, those characteristics cannot be obtained. This is because when the speed is lower than 300 m / min, the thermal energy is excessive and the crystal is coarsened, and when it exceeds 700 m / min, the thermal energy for softening cannot be sufficiently provided. it is conceivable that. 80m / mi
A traveling speed smaller than n results in poor production efficiency, resulting in high costs.

(Batch type annealing)
In the annealing by the batch method shown in Table 11, when the temperature of the heat treatment was set to 170 ° C. or higher and 700 ° C. or lower, the crystal grain size of the surface layer was reduced and excellent elongation could be obtained. On the other hand, when the temperature was 120 ° C. or lower, or 750 ° C. or higher, the above characteristics could not be obtained. This is because when the temperature is 120 ° C. or lower, recrystallization is not sufficient and a processed structure exists, and when it is 750 ° C. or higher, the crystal is coarsened by excessive heat. .

When the heat treatment time was within 3 hours, the crystal grain size of the surface layer was small and excellent elongation could be obtained. On the other hand, when the time exceeded 5 hours, the above characteristics could not be obtained. This is because if the time exceeds 5 hours, the crystal grains become coarse due to excessive thermal energy. In the case of the batch method, considering the speed of temperature rise and cooling, it is difficult to perform the treatment in a short time, and therefore 0.5 hours is appropriate as the lower limit of the heat treatment time.

From the above results, as a method for producing the soft diluted copper alloy material of the present invention, the degree of work is 50% or more, and the conditions of the annealing treatment after the process are temperatures 250 ° C. to 800 ° C., time 0.6 seconds to 10.
Annealing in a 0 second tubular furnace is desirable.

Moreover, as another form, the conditions of an annealing process are energizing voltage 21V-35V, and traveling speed is 10.
Annealing with a current-carrying annealer at 0 m / min to 600 m / min is desirable.

Moreover, as another form, the batch-type annealing whose conditions of annealing treatment are the temperature of 150 to 700 degreeC and 3 hours or less is desirable.

More specifically, when the diameter of the material to be annealed after processing is less than φ1.0 mm, the annealing process is performed at a temperature of 250 ° C. to 550 ° C. for a time of 0.6 seconds to 5.0 seconds. Annealing is more desirable, and as another form, the annealing treatment condition is an energization voltage of 21V to 33V.
In addition, annealing with a current-carrying annealer with a traveling speed of 300 m / min to 600 m / min is more desirable, and as another form, annealing conditions are more preferably batch annealing at a temperature of 150 ° C. to 550 ° C. for 3 hours or less. .

Moreover, when the wire diameter size of the material to be annealed after processing is φ1.0 mm or more, annealing is performed in a tubular furnace at a temperature of 300 ° C. to 800 ° C. for a time of 1.0 second to 10.0 seconds. More preferably, as another form, annealing conditions are more preferably annealing with a current-carrying annealer with an energization voltage of 25 V to 35 V and a traveling speed of 100 m / min to 500 m / min, and as another form, As for conditions, annealing by a batch method with a temperature of 170 ° C. to 700 ° C. for 3 hours or less is more desirable.

The manufacturing method of the soft dilute copper alloy material according to the present embodiment as described above has a degree of work before applying a soft dilute copper alloy containing Ti or the like and the remainder being made of copper by plastic working, and then performing annealing treatment.
By setting it to 0% or more, the average crystal grain size from the surface to the depth of 20% of the wire diameter at least from the surface can be reduced to 15 μm or less, so that it has high conductivity and high tensile strength even in a soft material. Since both elongation rates can be achieved, the connection reliability of the product can be improved.

As with the added Ti, M is used as a method for producing the soft diluted copper alloy material according to this embodiment.
Since the additive element selected from the group consisting of g, Zr, Nb, Ca, V, Ni, Mn, and Cr traps sulfur (S) as an impurity, the copper matrix phase as a matrix is highly purified, and the material The soft properties of the are improved. For this reason, it has been confirmed that by using the soft dilute copper alloy material as a copper bonding wire, it is possible to suppress the damage to the fragile aluminum pad on the silicon chip during bonding.

In addition, the soft dilute copper alloy material obtained by the manufacturing method according to the present embodiment does not require copper purification (99.999 mass% or more), and has high conductivity by an inexpensive SCR continuous casting and rolling method. Since it can be realized, the productivity is high and the cost can be reduced.

Furthermore, a copper bonding wire made of a soft dilute copper alloy material obtained by the manufacturing method according to the present embodiment can be applied as an alternative to an Al bonding wire of about φ0.3 mm for use in a vehicle power module, and has a high thermal conductivity of the material. By reducing the size of the module as the wire diameter decreases due to, and increasing the heat dissipation by improving thermal conductivity, it is possible to avoid a decrease in connection reliability due to an increase in current density.

Claims (8)

A soft soft copper alloy containing an additive element selected from the group consisting of Ti, Mg, Zr, Nb, Ca, V, Ni, Mn, and Cr, with the balance being copper, and then annealing. A method for manufacturing a diluted copper alloy material,
A method for producing a soft dilute copper alloy material, wherein a degree of processing in the plastic processing before the annealing treatment is 50% or more. 2. The soft dilute copper alloy material according to claim 1, wherein the soft dilute copper alloy material has a linear shape with a diameter of less than 1.0 mm, and the annealing treatment is performed at a temperature of 250 ° C. to 550 ° C. and a time of 0.6 seconds to 5.0 seconds. A method for producing a soft dilute copper alloy material, which is continuously performed by passing through a tubular furnace. In Claim 1, the soft dilute copper alloy material has a linear shape with a diameter of less than 1.0 mm, and the annealing treatment is performed in a range of energization voltage of 21 V to 33 V and travel speed of 300 m / min to 600 m / min. A method for producing a soft dilute copper alloy material, characterized in that the method is continuously performed by the method. 2. The soft dilute copper alloy material according to claim 1, wherein the soft dilute copper alloy material has a linear shape with a diameter of less than 1.0 mm, and the annealing treatment is performed by batch treatment at a temperature of 150 ° C. to 550 ° C. and a range of 3 hours or less. A method for producing a soft dilute copper alloy material. 2. The soft dilute copper alloy material according to claim 1, wherein the soft dilute copper alloy material has a linear shape having a diameter of 1.0 mm or more, and the annealing treatment is performed at a temperature of 300 ° C. to 800 ° C. and a time of 1.0 second to 10.0 seconds. A method for producing a soft dilute copper alloy material, which is continuously performed by passing through a tubular furnace. In Claim 1, the said soft dilute copper alloy material is a linear shape whose diameter is 1.0 mm or more, and the said annealing process is energization annealing in the range of energization voltage 25V-35V and running speed 100m / min-500m / min. A method for producing a soft dilute copper alloy material, characterized in that the method is continuously performed by the method. 2. The soft dilute copper alloy material according to claim 1, wherein the soft dilute copper alloy material has a linear shape with a diameter of 1.0 mm or more, and the annealing treatment is performed by batch treatment at a temperature of 170 ° C. to 700 ° C. and a range of 3 hours or less. A method for producing a soft dilute copper alloy material. In any one of Claims 1-7, the said soft dilute copper alloy is 2-12 mass ppm.
A method for producing a soft dilute copper alloy material, comprising sulfur of 2 mass ppm, oxygen of greater than 2 mass ppm and less than or equal to 30 mass ppm, and 4-55 mass ppm of Ti as the additive element.

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