JPH0523729A - Method for high speed drawing of extra fine steel wire - Google Patents

Abstract

(57) [Summary] [Purpose] To speed up and increase the efficiency of the drawing method for hard steel wire with a finishing wire diameter of 0.05 to 0.2 mm, which has been conventionally held at about 600 m / min. [Structure] In a wet slip continuous wire drawing machine, the number of dies is 35 to 50, cooling between dies is carried out in a water-soluble lubricating liquid by a total immersion method, and at least 10th die from the final die is drawn. Is fixed in the die holder using a spring material having a specific frequency ratio, and the finished wire diameter is 0.05 to 0.2 while preventing tension fluctuation and vibration on the wire.
Final drawing speed of hard steel wire of mm 1500-2500 m / min
Then, it is manufactured by giving a high area reduction processing with a total true strain of 4 to 6. [Effect] According to the present invention, the repeated use of the ultra-fine wire drawing machine is eliminated, and the ultra-fine steel wire having excellent mechanical properties and twisting property can be drawn at high speed, and the manufacturing cost of the ultra-fine wire can be reduced. Further, since the aging deterioration is small, it is possible to provide an ultrafine wire excellent in quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of continuously drawing a hard steel wire, a brass-plated steel wire, a Ni-plated steel wire or the like having a thickness of about 0.05 to 0.2 mm by a wet slip system.

[0002]

2. Description of the Related Art In a conventional ultrafine wire drawing machine, generally, a surface reduction ratio of 10 to 25% is used and 10 to 20 dies are used, and a total surface reduction ratio is 80 to 97% and a wire drawing speed of 600 m. /
A method of continuously drawing wire at about min is used.
In order to produce an extra fine wire of 0.05 to 0.2 mm, the number of dies required after the final patenting heat treatment is about 40. Therefore, it is necessary to repeatedly use the wire drawing machine twice or more. The final wire drawing speed is kept at around 600m / min in order to prevent wire breakage due to heat generation of steel wire during wire drawing.
There was a problem of low productivity. As a means for preventing wire breakage during wire drawing, for example, Japanese Patent Laid-Open No. 1-133608 discloses a method in which wire is twisted and then wire is drawn while releasing the twist, but it is broken because vibration is applied to the die. There is a problem that breakage is promoted in ultra-fine wires with a low load. Further, in Japanese Patent Laid-Open No. 64-62212, a wire drawing device is disclosed in which the outer diameter of each capstan is made the same, the contact length of the wire and the capstan is made the same, and the frictional force of pulling is made uniform to prevent wire breakage. However, it cannot be used for high-speed wire drawing because the multi-stage wire drawing machine is too complicated and the wire being drawn is not water-cooled. In addition, Japanese Patent Laid-Open No. 2-20
No. 031 discloses a wire drawing machine in which a cooling capstan that is not separately driven other than the pull-out capstan and the turn roller capstan is installed in the middle, but there is no regulation to prevent the vibration of the die, and the cooling of the die is not performed. Since the method is not specified, it cannot be used for high speed wire drawing.

[0003]

SUMMARY OF THE INVENTION In order to overcome such a situation, the present invention has a die number of 35 to 35 per wire drawing machine.
By mounting 50 sheets, the desired wire diameter (0.0
(5 to 0.2 mm) hard steel wire is obtained, and the space between the dies and the dies is completely immersed in the water-soluble lubricating liquid, and at least the tenth die from the final die is in the die holder. By fixing with a spring material having a specific frequency ratio, the wire stress fluctuation and vibration during high-speed wire drawing can be suppressed to a small level, and a high-speed wire drawing method for high-strength ultrafine steel wire with a low wire-drawing breakage rate can be provided. Is provided.

[0004]

Means and Actions for Solving the Problems The present inventors have
When drawing a hard steel wire with a wet slip continuous wire drawing machine, the breakage occurrence point is mainly within 10th die from the final die, and when drawing with the current 20 or so dies, It was experimentally confirmed that when the linear velocity exceeds 600 m / min, the aging deterioration is remarkably accelerated by the heat generation of the steel wire. Regarding the former, it is thought that the main cause is that the die vibration within 10th die from the final die is amplified and resonated, and the latter is due to the low cooling capacity between the dies, and the fixing method between the die holder and the dies. The inventors have found that improvement of the die-to-die cooling method is an essential condition for high-speed wire drawing, and have reached the present invention. That is, finishing wire diameter 0.05
In the method of wet slip continuous wire drawing of ultra-fine steel wire of ~ 0.2 mmφ, the number of dies used per wire drawing machine is 35 to 50
And between the dies and dies, completely submerged cooling in water-soluble lubricating liquid, and counting at least 10 from the final die.
The wire drawing die up to the die is fixed in the die holder by using a spring material having a frequency ratio of the following formula, and the final wire drawing speed 1500 while preventing tension fluctuation and vibration on the wire.
It is a method for drawing a high-strength ultra-fine steel wire, which is characterized by performing a high area-reduction rate machining with a total true strain of 4 to 6 at a rate of up to 2500 m / min.

1.5 ≦ f / f _o ≦ 4 where f is the vibration frequency of the die during wire drawing, f _{o is} the natural frequency of the spring material, and the finishing wire diameter is limited to 0.05 to 0.2 mm. The reason is that when the wire diameter is 0.05 mm or less, factors other than tension fluctuation / vibration, such as material cleanliness (inclusions) and non-uniform slip ratio of the wire drawing machine, capstan surface sprayed material, Since the main cause of disconnection is whether the lubricant is suitable or not, the thickness is set to 0.05 mm or more. On the other hand, since it is practically difficult to perform high surface reduction processing of true strain 4 to 6 on a thick wire diameter of 0.2 mm or more for a normal hard steel wire, an upper limit is set on the finished wire diameter.

Next, the reason why the number of dies mounted per wire drawing machine is limited to 35 to 50 is that it is not possible to draw wires to a desired wire diameter in one step with 35 or less dies, and 50 dies are used. In the above, the number of dies is already sufficient to draw the wire to the desired wire diameter, and rather the overall configuration of the continuous slip drawing machine becomes too large, which is not realistic, so it was defined as 50 dies or less. The reduction ratio of each stage of the die is not particularly limited, and either equivalent reduction at a reduction ratio of 8 to 14% at each stage or inclined reduction that gradually reduces the reduction ratio can be applied.

It has been specified that all the die-to-die cooling is completely submerged in the water-soluble lubricating liquid. Usually, a method of supplying an oil-based lubricating liquid or a water-soluble lubricating liquid to a steel wire between dies by a shower method is often adopted.
Since the steel wire cooling capacity is low, the heat generation of the steel wire during high-speed multi-stage wire drawing cannot be sufficiently suppressed, resulting in frequent wire breakage. Further, the method of completely submerging in the oil-based lubricating liquid has a problem that the wire resistance is increased and the viscosity of the oil is large, so that the steel wire is caught in the capstan and is broken. Since neither of the above methods is suitable as a cooling method for drawing ultra-fine steel wire at a high speed, cooling by a completely submerged type in a water-soluble lubricating liquid was specified.

Further, the reason why the fixing method between the die and the die holder is limited to the range from the final die to the 10th die is that the die before that has a drawing speed of 600 m / mi.
Because the speed is less than n, the tension fluctuations and vibrations on the wire are small and the breaking load of the wire is large enough even with the normal die fixing method, so it is difficult to lead to disconnection.

The type of spring material to be mounted in the die holder together with the die is not particularly limited as long as it is a mechanism such as a coil spring or a leaf spring that can absorb vibration. However, the following is defined as the natural frequency f _o of the spring material with respect to the frequency f of the die. 1.5 ≦ f / f _o ≦ 4 where, f: oscillation frequency f _o of the die in the drawing: reasons for limiting the natural frequency f / fo ≧ 1.5 of the spring material, f / fo <1. 5
This is because the vibration of the dice is amplified on the contrary and the disconnection is promoted. In addition, the reason for limiting f / fo ≤ 4 is that if it exceeds this value, the die will be integrated with the die box and the vibration of the die box itself will be picked up, which will easily lead to disconnection and the original effect of damping the vibration will disappear. The upper limit was specified. The number of total capstans is not particularly limited, but the number of dice is 40,
A large capstan cone causes eccentricity, blurring, etc., so it is desirable to use a total of about 6 to 7 axes.

Based on one embodiment of the method of the present invention,
The operation will be described. FIG. 1A is a schematic view of an entire apparatus showing an embodiment for implementing the method of the present invention, and FIG.
Shows a vertical sectional view thereof. All the capstans 3 to 8 were completely submerged in the water-soluble lubricating liquid 18, and 10 dies between the capstans 7 to 8 were installed in the die holder together with the coil spring having a frequency ratio of 3.0. With the wire drawing machine having this structure, it was possible to draw SWRS82A at a drawing speed of 2000 m / min and an ultrafine wire with a final finished wire diameter of 0.1 mm for 50,000 meters without any breakage. FIG. 2 is an example showing a method for fixing a die in a die box.
(B) is an example of the present invention using a leaf spring and a coil spring, respectively. FIG. 3A is a schematic view of a conventional ultrafine wire drawing machine, and FIG. 3B is a vertical sectional view thereof.

FIG. 4 shows a comparison of the heat generation status of the steel wire during wire drawing due to the difference in the cooling method between the dies. In the case of oil lubrication + shower cooling, or water lubrication + shower cooling, the heat generated by the steel wire during wire drawing is large and the die No. At around 30, the temperature of the steel wire already exceeded 200 ° C, and many wire breakages occurred.
Therefore, the actual wire drawing speed had to be suppressed to about 600 m / min. On the other hand, in the water lubrication + total immersion cooling method of the example of the present invention, the heat generation of the steel wire was suppressed to 200 ° C. or less even in the 40-stage die, and there was no disconnection during wire drawing. FIG. 5 shows the relationship between the frequency ratio of the spring material that fixes the die and the frequency of wire breakage during wire drawing. It can be seen that the disconnection rate can be significantly reduced in the frequency ratio range of 1.5 to 4.0.

Table 1 shows examples. Experiments were conducted by changing the finishing wire diameter, the number of dies, the cooling method between dies, the method of fixing the dies, the number of capstans, and the amount of processing strain (true strain).
Table 1 shows the results of evaluation of the frequency of wire breakage during wire drawing, the temperature of the final steel wire, the mechanical properties of the wire drawn material, and the twisting workability.

Inventive Examples 1 and 2 are steel type SWRS82A,
Inventive Examples 3 and 4 are examples in which a low alloy steel containing Si—Cr could be drawn at a high speed of 1500 m / min or more. There was no disconnection during wire drawing, the final wire drawing speed was 200 ° C or less, and the die vibration was suppressed to a small level. Further, the mechanical properties of the drawn wire material were such that high strength-ductility was secured, and twistability was also good.

In Comparative Example 1, since the finishing wire diameter was too small,
This is an example in which the slip ratio on the capstan that raises the wire drawing speed becomes non-uniform and wire breakage occurs, and the wire drawing speed remains at 400 m / min. On the contrary, Comparative Example 2 is an example in which the wire diameter could not be drawn up to a predetermined true strain because the finished wire diameter was too large. Comparative Example 3 is an example in which the tensile strength of the wire drawing material was low and the wire drawing speed remained at 1200 m / min because the true strain amount was small. On the contrary, Comparative Example 4 is an example in which wire drawing could not be performed because the true strain amount was too large.

Comparative Example 5 is an example in which since the number of used dies was small, the area reduction rate of each stage of the die was inevitably large, and remarkable die wear, steel wire heat generation and ductility deterioration of the wire drawing material occurred. .. In Comparative Example 6, since the number of dies used was unnecessarily large, the area reduction ratio at each step was small, and in this case also, die wear occurred and ductility of the wire drawing material decreased. Comparative Examples 7 and 8 are examples in which the cooling between steel dies was low because the cooling between the dies was performed, and the disconnection frequently occurred due to aging embrittlement. The wire drawing speed remained at about 600 to 800 m / min, the ductility of the wire drawn material was low, and the twisting workability was also poor.
Comparative Example 9 is an example in which the cooling between the dies was low and the wire resistance was high because wire-immersion type was set in the oil lubricating liquid, and wire drawing could not be performed.

Comparative Example 10 is an example in which the die vibration could not be completely suppressed because the fixing between the die holder and the die was as small as two sheets from the final die, so that disconnection occurred. Comparative Example 11 is an example in which the vibration of the die was inversely amplified and wire drawing could not be performed because the spring material having a too small frequency ratio was used for fixing the die. Comparative Example 12 is an example in which the die holder and the die were not fixed in particular and was set in a free state, and the frequency of wire breakage was extremely high. Comparative Example 13 is an example in which a spring material having an excessively high frequency ratio was used for fixing the die, so that the disconnection frequently occurred due to the vibration of the die holder itself.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

INDUSTRIAL APPLICABILITY As described above, the present invention not only shortens the manufacturing process of the ultra-fine steel wire, which has been repeated twice or more in the conventional ultra-fine wire drawing machine, to one process, but also improves the wire drawing speed. From the conventional 600 m / min to a maximum of 2500 m / min, the productivity can be improved, and the production cost of the ultrafine wire can be reduced, which is a great effect. In addition, the drawn wire has excellent mechanical properties such as strength-ductility and twisting workability, and has little aging deterioration, so that it is possible to provide an ultrafine wire of excellent quality.

[Brief description of drawings]

FIG. 1A is an example of an overall view of an apparatus for implementing the present invention, and FIG. 1B is a vertical sectional view thereof.

FIG. 2 shows an example of a method of fixing a die in a die holder.

FIG. 3A is a schematic view of a conventional ultrafine wire drawing machine, and FIG. 3B is a vertical sectional view thereof.

FIG. 4 is a diagram showing a comparison of heat generation states of steel wire during wire drawing due to differences in cooling methods between dies.

FIG. 5 is a diagram showing a relationship between a frequency ratio of a spring material fixing a die and a frequency of disconnection during wire drawing. 1,1 'Supply bobbin 2,2' Steel wire 3-9 Drive capstan 3 ', 5' Turn roller capstan 4 ', 6' Drive capstan 10-12 Wire drawing die 10 ', 11' For wire drawing Dies 13 to 15 Dice box 13 ', 14' Dice box 16, 16 'Finishing die 17, 17' Winding bobbin 18 Water-soluble lubricating liquid 18 'Oil-based lubricating liquid 19 Oil-based lubricating liquid supply shower 20 Leaf spring 21 Coil spring

Claims (1)

Claim: What is claimed is: 1. A wet slip continuous wire drawing method for an extra fine steel wire having a finished wire diameter of 0.05 to 0.2 mmφ, wherein the number of dice used per wire drawing machine is 35 to 50, and Completely submersible in a water-soluble lubricating liquid between the dies and dies, and for drawing wire dies up to at least the 10th die from the final die, use a spring material with the following frequency ratio in the die holder. At the final wire drawing speed of 1500 to 2500 m / min while preventing tension fluctuation and vibration on the wire.
A method for drawing a high-strength ultrafine steel wire, characterized by performing a high surface-reduction rate working with a total true strain of 4 to 6. 1.5 ≦ f / f _o ≦ 4 where, f: oscillation frequency of the die in the drawing f _o: natural frequency of the spring member