JPH06106226A - Wire drawing method - Google Patents

Abstract

PURPOSE:To provide a wire drawing method by which a fine diameter wire excellent in dimensional accuracy, surface properties can be obtained without shortening the die life irrespective of a large working load to a die. CONSTITUTION:A 1st die 1 and a 2nd die 2 for obtain a specified cross section shape and a prescribed wire diameter by drawing a wire material 5 further after it passes the 1st die are used. The outer periphery of the wire material is sealed with sealer 3 between these dies and the wire is drawn at an entrance part of the 1st die 1 with supplying of a lubricant. Since the lubricant stuck on the wire material advances in sequence into a sealed space 4 and the pressure of the lubricant is raised here, lubricating effect is enhanced at the 2nd die part large in working load and seizure and die wear are restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing a metal wire with a die, and more particularly to a method suitable for drawing a modified wire by changing the cross-sectional shape of a bus bar which is a starting material on the way. .

[0002]

2. Description of the Related Art Conventionally, when a high-precision wire having a wire diameter of 2 mm or less is produced, there is a limit to the accuracy of wire drawing with a roller, so that the wire is processed by a die.

[0003] Wire drawing with a die causes severe wear when the surface reduction rate and the amount of processing of a wire with a single die are large, and seizure also occurs, resulting in a shorter die life. In addition, disconnection or the like occurs, which adversely affects productivity. For this reason, it is often the case that the number of dies used is increased and the processing load per piece is reduced to gradually reduce the wire diameter, but such a method cannot be adopted depending on the type of wire to be manufactured. is there.

For example, when a bus bar of a round wire is drawn to obtain a modified wire such as a square wire, a die having a modified hole is
Even if the area reduction rate of the wire due to the die is substantially equal to zero, the cross-sectional shape of the wire must be changed, which increases the processing load.

The die, which has a heavy working load, is easily worn and seized even if wet drawing is performed using a lubricant. This is due to the fact that no high lubrication effect was obtained with conventional wet drawing.

In view of the above, according to the present invention, the lubricating effect at the time of wet wire drawing is naturally enhanced, so that the life of the die is improved and the surface quality of the obtained wire is improved even if the die has a heavy working load. Is intended to provide.

[0007]

According to the present invention, in order to achieve the above-mentioned object, the die to be used is made to have a predetermined cross-sectional shape and diameter by further narrowing the first die and the line after passing through the first die. There are two types of second dies, and a method in which the periphery of the wire is sealed between the dies and a lubricant is supplied at the inlet of the first die to perform wire drawing.

The first die may be a combination of a plurality of die in which the cross-sectional area of each machined hole is temporarily reduced.

The first die for manufacturing the modified wire has a shape similar to that of the busbar and has a cross-sectional area of 120 to 80% of that of the busbar.
The second die is provided with a modified processed hole for substantially forming.

[0010]

The lubricant supplied at the entrance of the first die adheres to the surface of the busbar and is drawn into the sealed space formed around the wire rod between the dies by the movement of the busbar one after another. For this reason, the pressure of the lubricant rises in the sealed space, a kind of forced lubrication is performed on the second and subsequent dies, and the thickness of the lubricating film becomes relatively thick, which prevents die wear and seizure. Have an effect on.

[0011]

FIG. 1 shows an example of the wire drawing method of the present invention.
In the figure, 1 is a first die, 2 is a second die, 3 is a seal arranged between the first die and the second die, 4 is a space created between the dies 1 and 2 and the seal 3 and the wire 5. .
This FIG. 1 shows a first bus having a circular cross section and a first hole having a round hole.
An example is given in which the wire diameter is slightly reduced by passing through the die 1 and the cross-sectional shape is slightly changed in some cases, and then the irregular-shaped wire having a quadrangular cross-section with a minute rounded corner is finished.

The seal 3 is sandwiched between the dies 1 and 2 to generate a sealing pressure on the contact surface with the dies.
Therefore, the space 4 is substantially sealed during the wire drawing process, and the lubricant supplied to the inlet of the die 1 and adhering to the outer peripheral surface of the wire 5 enters the space 4 one after another. For this reason, the pressure of the lubricant increases in the space 4, and the lubricant is forcibly fed into the second die 2 by this pressure, and as a result, the film thickness of the lubricant in the second die portion becomes thicker and the lubricating effect is increased. And seizure and die wear are reduced.

FIG. 2 shows a case where a generatrix having a circular cross section is processed to finish it into a triangular wire.
I am using one. These two dies 1 and 1 have a cross-sectional area of a machined hole on the right side in the drawing smaller than that on the left side. In this way, when the wire diameter is gradually reduced by using a plurality of first dies, or when the cross-sectional shape of the wire is gradually approached to the final shape, the particular die is not overloaded. , Which is advantageous in terms of averaging die life.

For a die which is first drawn, the effect of forced lubrication cannot be obtained. Therefore, the cross-sectional shape of the machined hole is the same as or close to that of the bus bar, and the cross-sectional area of this hole is also the bus bar. It is desirable to set it in the range of 120 to 80%. Even if the cross-sectional area of the machined hole is larger than that of the generatrix, the wire diameter increases due to wire drawing by the die in the forward direction, so that the space 4 can be sealed.

The experimental results for confirming the effects of the present invention will be described below.

A Cu--Sn alloy round bus bar having a diameter of 0.570 mm was used as a starting material, and a cross-sectional area of 0.20 was obtained with the die shown in FIG.
A square wire corresponding to 0 mm ² was manufactured.

In the first die 1, the processed hole has a round cross section and the hole diameter is 0.568 mm. The second die 2 has a side length of 0.45 mm and a corner radius of 0.05.
A machined hole having a square cross section of mm was used. Further, both end surfaces of the seal 3 and the seal contact surfaces of the dies 1 and 2 are mirror-finished, and the dies 1 and 2 are drawn together by a tightening tool to tightly sandwich the seal 3 between the dies. In addition, the approach angles of the dice 1 and 2 were both 12 °.

When the above-mentioned bus bar was drawn under the above-mentioned conditions while being lubricated with a lubricating oil, a wire having a good surface condition was obtained without any dimensional change even when the drawing amount reached 1 Ton.

On the other hand, when drawing the wire while supplying the lubricant only by the second die without using the first die, only 10
When 0 kg of wire was drawn, seizure occurred at the corner of the machined hole, resulting in disconnection.

[0020]

As described above, according to the method of the present invention, two types of dies are used, and a simple structure in which the outer circumference of the wire rod is sealed between the dies has good dimensional accuracy and surface quality. It is possible to obtain a small diameter different diameter wire with high productivity without causing trouble such as disconnection.

Further, since the second and subsequent dies are effectively prevented from wear and seizure due to the forced lubrication effect, the life of the dies is extended.

The method of the present invention can be effectively used for ordinary wire drawing in which the cross-sectional area of the wire is simply reduced without changing the cross-sectional shape. That is, since the die life is extended by improving the lubrication effect, it is possible to increase the area reduction rate per die during normal wire drawing and reduce the total number of dies used.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a wire drawing method of the present invention.

FIG. 2 is a sectional view of another embodiment.

[Explanation of symbols]

 1 1st die 2 2nd die 3 Seal 4 Space 5 Wire rod

Claims (3)

[Claims] 1. In a wire drawing method for drawing a bus bar through a die, the die used is a second die in which the first die and the wire after passing through the first die are further narrowed to have a predetermined cross-sectional shape and diameter. The wire drawing method is characterized in that the wire rod is sealed between the dies, and a lubricant is supplied at the inlet of the first die to perform wire drawing. 2. As the first die, one having a machining hole similar to the busbar cross section and having a machined hole having a cross-sectional area of 120 to 80% of that of the busbar is used, and further, the second die has a cross-sectional shape different from that of the busbar. The wire drawing method according to claim 1, wherein a wire having holes is used. 3. The wire drawing method according to claim 1, wherein a plurality of first dies are used, and the first dies are those in which the cross-sectional area of each machined hole is temporarily reduced.