JP2001219214A - Dies for wire drawing - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Even when a coating layer is relatively hard and a core wire is soft like a copper-coated aluminum wire, it is possible to prevent application of uneven working force to the core wire and the coating layer, Provided is a die for wire drawing that is suitable for processing a composite filament that can prevent peeling and disconnection of a coating layer. SOLUTION: A drawing die is an arc die in which a cross section of a surface including a striatum to be drawn has an arc shape.
In this arc die, the ratio (L / D) of the length (L) of the bearing portion and the inner diameter (D) of the bearing portion where the inner diameter of the through-hole through which the striated body passes is minimized, is 1/2 or more. 2/3
It is. This wire-drawing die is suitable for wire-drawing a copper-coated aluminum wire using aluminum or an aluminum alloy as a core wire and using copper or a copper alloy as a coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire drawing process suitable for drawing a composite wire such as a copper-coated aluminum wire used as a conductor material for electronic parts or a center conductor material of a coaxial cable for CATV. The present invention relates to a die for wire drawing, and more particularly to a die for wire drawing capable of improving the bonding property between a copper-coated material constituting the copper-coated aluminum wire and a relatively soft aluminum core wire.

[0002]

2. Description of the Related Art Recently, conductor materials for electronic parts have been developed.
A composite filament having improved solderability and reduced weight has been proposed. In addition, there is a composite linear body for the center conductor of a CATV coaxial cable that is lighter in weight. As such a composite wire, for example, a copper-coated aluminum wire in which a lightweight aluminum wire is used as a core material and a high conductivity copper or copper alloy is coated as a coating material and joined is developed and put into practical use. .

A method of manufacturing a copper-coated aluminum wire includes, for example, vertically attaching a copper tape to an aluminum wire, coating the aluminum wire with the copper tape, and then applying a copper tape at a butt end parallel to the longitudinal direction of the aluminum wire. There is a tape cladding method or the like in which the aluminum wire and the copper tape portion are adhered to each other by welding each other and then drawing.

[0004] A through die is generally used for drawing and drawing the filament. FIG. 2 is a schematic cross-sectional view showing an example of the through die. The through-hole 6b of the through-type die 7 is roughly divided into five parts. An entrance part 1b (bell mouth) which is an insertion part of the wire and compresses the edge of the wire, and a hole diameter smaller than the entrance part 1b, An approach portion 2b in which the hole diameter gradually decreases in the wire passage direction, and a reduction portion which is further reduced in diameter from the approach portion 2b and has a predetermined wire drawing diameter and reduces the diameter of the wire to the predetermined wire drawing diameter. 3b
And a back relief portion 5b corresponding to a discharge portion of the wire rod.

[0005] The dies are classified into arc dies and conical dies according to the shapes of an entrance portion and an approach portion into which a wire is inserted.

The arc die has a cross-sectional shape of a plane including the center of the through-hole which is curved in an arc shape, and has a cross-sectional shape such that the line entrance and the line exit are widened around the reduction portion. . This arc die is mainly used for drawing a single line of non-ferrous metal.

The conical die has a conical cross section on the surface including the center of the through hole, and the entrance section and the approach section each have a linear cross section. The angle formed between the center line of the through-hole and the wall surface of the through-hole is called a die half angle, and various conical dies are used depending on the die half angle. This conical die is mainly used for drawing a single wire such as an iron wire and a steel wire.

On the other hand, when a composite wire in which a core material is coated with a coating material around a core wire is subjected to wire drawing by integrating the core wire and the coating material, a forced pressure lubrication type as shown in FIG. 3 is generally used. (Japanese Patent Application Laid-Open No. 6-106226).

3 is a combination of a plurality of dies including a die 10a and a dice 10b. The dice 10a and the dice 10b have through holes 17 and dice different in inner diameter and shape, respectively. 18
have. These dice 10a and dice 10b
Are arranged such that the through holes 17 and 18 are located coaxially, and the space between the dice 10a and the dice 10b is sealed by a seal 14.

[0010] When wire drawing is performed using the dies configured as described above, the composite wire 15 is formed at the entrance of the die 10a.
After the lubricant is applied to the outer peripheral portion of the die, the composite wire 15 is inserted from the entrance of the die 10a. The lubricant applied at the entrance of the die 10a is successively drawn into the sealed space 12 between the seal 14 between the dies 10a and 10b and the composite wire 15 as the composite wire 15 moves. For this reason, the pressure of the lubricant accumulated in the sealed space 12 increases, and the lubricant is sent into the die 10b at a high pressure.
5 is smoothly fed and wire-drawn.

[0011]

However, the forced-pressure lubrication type wire drawing method using the dies is mainly used for wire drawing of a composite wire having a relatively soft surface layer and a hard core wire. However, it is not suitable for a composite wire having a relatively hard surface layer and a soft core wire.

For example, when a copper-coated aluminum composite wire is drawn using a forced-pressure lubricating die set in a state where the copper-coated material and the aluminum core wire are not completely bonded to each other, the aluminum core wire is formed. Since it is softer than the copper layer of the coating material, only the aluminum core wire is processed without processing the copper layer of the coating material. Also, when the pressure of the lubricant fluctuates in the longitudinal direction of the copper-coated aluminum composite wire, a drawing force is unevenly applied to the composite wire, and the soft aluminum core wire receives tensile and compressive forces unevenly in the longitudinal direction. ,
There is a problem that a portion having a large diameter and a portion having a large diameter and a portion having a small diameter and a small diameter appear in the longitudinal direction of the composite wire, and the copper-coated aluminum wire may be disconnected.

[0013] Further, if wire drawing is performed using one ordinary arc die or conical die without using a forced pressure type die, when the bonding between the copper layer and the aluminum core wire is insufficient, The copper layer and the aluminum core wire are non-uniformly processed, and constriction of the aluminum core wire occurs, and cracks are generated in the copper layer due to such constriction and non-uniform processing. When a crack occurs in the copper layer in this way, the copper layer peels off, and in an extreme case, disconnection occurs.

The present invention has been made in view of such a problem, and even when the coating layer is relatively hard and the core wire is soft, such as a copper-coated aluminum wire, the core wire and the coating layer are not uniform. It is an object of the present invention to provide a wire drawing die suitable for processing a composite filament that can prevent application of a processing force and can prevent peeling and disconnection of a coating layer.

[0015]

A wire-drawing die according to the present invention is an arc-shaped die in which a cross section of a surface including a wire to be drawn has an arc shape, and wherein the wire is passed. The ratio (L / D) of the length (L) of the bearing portion that minimizes the inner diameter of the through hole to the inner diameter (D) of the bearing portion is １ ／.
乃至 to 特 徴.

In the wire drawing die, the striated body is made of aluminum or an aluminum alloy as a core wire,
It can be a copper-coated aluminum wire using copper or a copper alloy as a coating material.

In the present invention, the shape of the dies is such that the type of the dies is an arc die having a single piece, and the length L of the bearing portion is １ ／ to ／ of the inner diameter D of the bearing portion. By specifying, even when the coating layer is harder than the core wire, such as copper-coated aluminum composite wire, the coating layer is smoothly drawn without peeling and disconnection of the coating layer. can do.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of a wire drawing die according to an embodiment of the present invention. As shown in FIG. 1, the dice 20 are located at the entrance 1
a, an approach portion 2a, a reduction portion 3a, a bearing portion 4a, and a back relief portion 5a. The through-hole 6a has a shape like a mouth of a trumpet in which the drawn wire discharge portion (back relief portion 5a) in the drawing direction is narrow in the horizontal direction and the composite wire introduction portion (entrance portion 1a) in the drawing direction is wide. It is curved in an arc from the entrance 1a to the approach 2a. The length (L) of the bearing portion 4a located at the minimum diameter of the die 20 and the bearing portion 4
The ratio (L / D) of a to the inner diameter (D) is 乃至 to ／.

In the wire-drawing die thus constructed, for example, after a copper tape is vertically attached to an aluminum wire, the copper tape is rolled, and the butted ends are welded to join the composite wire 25. (Tape cladding method),
The resulting composite wire 25 is rolled by a cold rolling mill or the like to remove a gap between the coating material and the core material, and then inserted into the die 20. In the die 20, first, the composite wire 25
After the lubricant is applied to the outer peripheral portion, the entrance portion 1a
And the edge is compressed, and then the composite wire 25 is temporarily compressed through the approach portion 2a and the reduction portion 3a, and is reduced in diameter by the bearing portion 4a to have a final wire diameter. Sent out via

The length of the bearing part 4a and the bearing part 4
If the ratio of the inner diameter of the composite wire 25 to the inner diameter of the composite wire 25 is in the range of 乃至 to ／, the lubricant applied to the outer peripheral portion of the composite wire 25 is
Since the wire a enters the wire a, the pulling force of the composite wire 25 does not extremely increase. Therefore, the joining property between the covering material of the composite wire 25 and the drawn wire is enhanced, and the wire can be drawn without breaking.

In order to prevent the lubricant pressure from being excessively increased, the inventors of the present application conducted an experiment in order to determine a die shape that can improve the bonding property between the copper coating layer and the aluminum core wire by using a single-die configuration. As a result of the research, it has been found that the object of the present invention can be achieved by making the length L of the bearing portion of the arc die to be １ ／ to ／ of the inner diameter D of the bearing portion.

For example, a conical die having a die half angle of 8 ° and 16 ° and an arc die having a bearing length of 1 to 2 mm are used, and one of these dice is used to extend a copper-coated aluminum wire. When wire processing was performed, the circular die was the one having the best bondability between the copper coating layer and the aluminum core wire. Therefore, the length of the bearing portion was variously changed using an arc die, and the bonding property between the copper coating layer and the aluminum core wire was evaluated. As a result, when the length L of the bearing portion was less than 1/2 of the inner diameter D, In some cases, the wire is easily broken during wire drawing, but the length L of the bearing portion is 部 of the inner diameter D.
With the above, the drawing value is good and the wire can be easily drawn without breaking. On the other hand, when the length L of the bearing exceeds 2/3 of the inner diameter D, the flow of the lubricant into the bearing portion decreases, and the required pulling force increases.
Drawability decreases. On the other hand, if the length L of the bearing portion is not more than 2/3 of the inner diameter D, the deterioration of the drawability is avoided, and the copper-coated aluminum composite wire can be drawn without breaking. it can. Therefore, in the present invention, an arc die is used, and the length L of the bearing portion is set to 乃至 to ／ of the inner diameter D. The aperture value is an index indicating how much the cross-sectional area can be reduced by wire drawing, and is a ratio (%) obtained by dividing the reduced cross-sectional area by the original cross-sectional area.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The effects of the wire drawing dies according to the embodiments of the present invention will be specifically described below in comparison with comparative examples.

First, a copper tape having a thickness of 0.4 mm was vertically attached to an aluminum wire having a diameter of 9.5 mm by a tape cladding method, and the aluminum tape was rolled and formed so as to be wrapped with the copper tape. Then, at the butt end extending in the longitudinal direction of the aluminum wire, a copper tape is
Joining was performed by a welding method to obtain a copper-coated aluminum wire. Next, the obtained copper-coated aluminum wire is rolled by a multi-stage sizing roll having circular grooves arranged in tandem to eliminate a gap between the copper layer and the aluminum core wire, and a copper-coated aluminum wire for wire drawing is formed. And

Next, by using various arc dies and conical dies in which the ratio of the length of the bearing to the inner diameter of the die is changed, the copper-coated aluminum wire is formed to have a diameter of 10.3 mm.
From 0.9 to 0.9 mm. Thereafter, a joining test was performed by conducting a tensile test, and after confirming that the joining property was sufficient, a copper-coated aluminum wire having a diameter of 50 μm was obtained by a fine drawing step.

The ratio of the length (L) of each bearing to the inner diameter (D) of the bearing, the half-width of the die, the bondability of the copper-coated aluminum wire at a diameter of 0.9 mm (result of tensile test), and the evaluation after the wire drawing were performed. It is shown in Table 1 below. However, in the column of bondability, ○ indicates no peeling, Δ indicates small peeling, and x indicates large peeling. Further, in the column of appearance of elasticity, 場合 indicates that there is no crack, Δ indicates that the film can expand and contract, but X indicates that there is a crack, and X indicates that a disconnection has occurred.

[0027]

[Table 1]

Example No. No. 1 is an example in which the ratio of the length of the bearing portion to the inner diameter of the bearing portion is 2/3. After a copper-coated aluminum wire was drawn to a diameter of 0.9 mm, a tensile test was performed. The bondability between the copper and the aluminum wire of the core material was good, and no disconnection was observed even when the wire was drawn to 50 μm.

Example No. No. 2 is an example in which the ratio of the length of the bearing portion to the inner diameter of the bearing portion was １ ／, and the bondability of the copper-coated aluminum wire at a diameter of 0.9 mm was good. I was not able to admit.

On the other hand, in Comparative Example No. 1 where the ratio of the length of the bearing portion to the inner diameter of the bearing portion was 1. In the case of 3,
The amount of lubricant that enters the bearing part is reduced, and when drawing copper-coated aluminum wire to a diameter of 0.9 mm, the pulling force of the composite wire increases. As a result, peeling was observed between the copper layer and the aluminum core. Further, when wire drawing was performed to 50 μm, disconnection occurred due to cracking or peeling of the copper layer.

Further, in Comparative Example No. 1 in which the ratio of the length of the bearing portion to the inner diameter of the bearing portion was 1/3. At 4, 0.9
mm, the bondability after the tensile test was
Although wire drawing was possible, cracks were seen in the appearance after wire drawing.

Furthermore, in Comparative Example No. 5, the ratio of the length to the inner diameter of the bearing part is within the range of the present invention,
Since this comparative example was a conical die, the bonding property was low. Comparative Examples Nos. 6 and 7 were also conical dies, and the ratio was 1/3. Therefore, the bondability was poor, and the copper layer was cracked by wire drawing up to 50 μm.

[0033]

As described in detail above, according to the present invention,
Die bearing length L and inner diameter D
And the ratio L / D is 1/2 to 2/3, so that the covering material can improve the bonding property between the covering material of the hard composite wire and the core wire as compared with the core wire, and The composite wire can be smoothly drawn without breaking. In addition, since the lubricant is sufficiently supplied to the bearing portion of the die, a composite wire having a good finish can be obtained, and the drawing force of the composite wire does not increase extremely, so that the wire drawing processability is improved. .

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a wire drawing die according to the present embodiment.

FIG. 2 is a schematic sectional view showing a structure of a through die.

FIG. 3 is a schematic cross-sectional view showing a set of dies used in a method of wire drawing a composite wire.

[Explanation of symbols]

 1a, 1b; Entrance part 2a, 2b; Approach part 3a, 3b; Reduction part 4a, 4b; Bearing part 5a, 5b; Back relief part 7, 10a, 10b; Die 12; Sealed space 14; Seal 15, 25; Line 20; dice

Claims (2)

[Claims] A cross-sectional shape of a surface including a striated body to be drawn is an arc-shaped die, and a length of a bearing portion that minimizes an inner diameter of a through hole through which the striated body passes ( L)
And the ratio (L / D) of the bearing portion to the inner diameter (D) of the bearing portion is 1
/ 2 to 2/3. 2. The wire drawing die according to claim 1, wherein the striated body is a copper-coated aluminum wire having aluminum or an aluminum alloy as a core wire and copper or a copper alloy as a coating material. .