JPH057931A - Wire drawing method for metallic wire rod - Google Patents

Abstract

PURPOSE:To realize short time descaling of a cold metallic wire rod and high wire drawing of wire drawing executed continuously thereafter. CONSTITUTION:Scale is eliminated by allowing a water jet of 1000-10000Kg/cm<2> pressure to come into collision with a wire rod 1 on which scale is generated due to oxidation of the surface, and subsequently, wire drawing is executed by supplying a wet lubricant converted to extra high pressure between dies from the outside. In this case, a ratio 1/d of the diameter (d) of water jet injection nozzle at the time of descaling and a distance 1 extending from the nozzle tip to the wire rod is set to 100-800. Also, wire drawing is executed by supplying a dry lubricant, and an extra high pressure wet lubricant to a first stage of a multistage wire drawing die, and a second stage and thereafter, respectively. In such a way, environmental pollution at the time of descaling and wire drawing of a cold metallic wire rod is prevented, the work environmental improvement is attained, and simultaneously, short time descaling and high speed wire drawing can be executed, and the quality improvement and the productivity improvement can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold descaling of a strand-shaped metal wire and a subsequent wire drawing method.

[0002]

2. Description of the Prior Art Scale produced by the oxidation of metals must be removed prior to drawing. Generally, this removal method is roughly classified into a chemical method and a mechanical method, and the former method mainly uses sulfuric acid or hydrochloric acid. The metal surface after pickling becomes fine irregularities, firmly holds lime, borax, etc. to form a good film, and has the function of improving the drawing of the lubricant during wire drawing. Had been used. However, in recent years, the latter has become widespread from the viewpoint of pollution prevention related to a large amount of waste acid treatment problems.

The latter includes a reverse bending method, a shot blasting method, and an air blasting method disclosed in JP-A-50-56323 and JP-A-54-85125.

The reverse bending method is difficult to be completely descaled, and a fine scale often remains. Therefore, the steel type and wire diameter are limited in its application. Further, the shot blasting method and the air blasting method have a problem that a red rust portion remains as a pattern and foreign matter is caught.

Also in these mechanical methods, it is necessary to install a dust collector as an environmental measure. Furthermore, in these conventional techniques, in the process of continuously performing descaling and subsequent wire drawing, the time required for descaling is long, and the equipment is lengthened as the wire drawing speed increases,
There is also a problem that equipment costs and running costs increase.

Next, in the wire drawing process following the descaling, the dry film drawing process is usually carried out because the lubricating film thickness on the die processed surface becomes thicker and the drawing speed can be increased.

However, dry drawing cannot sufficiently cool the steel wire at the time of drawing, and there is a risk of strain-age embrittlement of the steel wire. Therefore, in the continuous wire drawing step of arranging a plurality of dies in series and wire drawing, a method of winding steel wire around a storage drum (capstan) between the dies and blowing air to cool it is used. However, the effect is small and there is a problem that the lubricant adhered to the surface of the wire is blown off and the working environment is deteriorated. Further, in Japanese Patent Laid-Open No. 50-19617,
A method has been proposed in which the steel wire is forcibly cooled immediately after the exit of the wire drawing die to prevent strain-age embrittlement.

However, this method also requires cooling during the limited wire drawing process, and the speeding up of the wire drawing speed shortens the cooling time and does not necessarily bring about a sufficient effect.

On the other hand, wet drawing has a lubricating property, a cooling property, and a cleaning property because water is used as a lubricant, but since the lubricating property is inferior to that of a dry lubricant, it has a diameter of about 2 mm or more. High-speed wire drawing is not possible with diameter wire rods. Therefore, the thick wire is only used as a wire drawing method when the lubricant should not remain unnecessarily on the finished surface. Further, JP-A-54-143753 proposes a method of supplying a lubricant at a high pressure and forcibly lubricating the wire.
However, this method is a simple roughing process that can be performed for a short time such that unevenness is created on the smooth surface after peeling, and then wire drawing, and the scale produced by hot rolling is cooled by the conventional method. It is not suitable for the continuous method in which descaling is performed and then high speed wire drawing is performed.

[0010]

The present invention provides a clean descaling method for preventing deterioration of the work environment, water pollution, etc., which are problems at the time of descaling of steel wire before drawing, and a wire drawing subsequently performed. It is intended to provide a wire drawing method capable of increasing the drawing speed by using wet drawing which is excellent in cooling property, cleaning property and cleanness.

The gist is as follows: (1) The scale is removed by colliding a water jet of an ultrahigh pressure liquid having a pressure of 1,000 to 10,000 Kg / cm ² with a metal wire rod on the surface of which the scale has been generated by oxidation. Then
Then, a method for drawing a metal wire material that enables high-speed wire drawing by externally supplying a lubricant for wet wire drawing that has been made ultra-high pressure to a high pressure chamber between dies. (2) In a method of removing a scale by colliding a water jet of an ultra-high pressure liquid, an inner diameter d of an injection nozzle
And the ratio of the distance l from the nozzle tip to the metal wire (l /
d) is set to 100-800.
A method for drawing a metal wire as described. (3) The first of the wire drawing dies arranged in series
A wire drawing lubricant is supplied to the diameter-reducing dies of the second stage, and an ultrahigh-pressure lubricant for wet wire drawing is supplied to the diameter-reducing dies of the second and subsequent stages to perform wire drawing. 1. The method for drawing a metal wire according to 1.

[0012] That is, according to the present invention, the pressure is 100
The ultrahigh pressure liquid of 0 to 10,000 Kg / cm ² is used as the high density energy of the water jet to collide with the cold steel wire to perform descaling, and the subsequent wire drawing is
The conventional problem is solved by press-fitting a wet lubricant whose pressure has been increased to almost the same level as descaling according to the purpose after wire drawing into the die-worked surface.

FIG. 1 shows a continuous wire drawing apparatus incorporating an ultrahigh pressure water jet descaling apparatus of the present invention and an apparatus for pressurizing an ultrahigh pressure wet lubricant into a wire drawing die.

Here, 1 is a steel wire, 2 is a supply stand,
3 is a straightening machine, 4 is an ultrahigh pressure descaling device, 6 is a 2-die wire drawing device, 10 is a winding drum (capstan), and 11 is a hydraulic booster pump (intensifier).

[0015]

Here, the reason why the ultrahigh-pressure liquid having a pressure of 1,000 to 10,000 kg / cm ² is made to collide with the scale-generated metal wire rod as a water jet is to make droplets of jet high-speed water jet structure. It utilizes the destructive force of the water hammer action generated by the rapid compression when the droplets generated in the flow region collide with the metal wire rod without any difficulty. At the moment when the droplet hits the metal surface at a speed higher than the speed of sound, there is a portion that cannot be deflected to the side due to fluidization due to too much speed.

That is, the central portion of the tip of the droplet is compressed, and an impact pressure is generated instantaneously. This impact pressure reaches about 10 times the supply pressure and acts intermittently on the surface of the metal wire rod, thereby destroying and dropping the scale and descaling. Here, the lower limit pressure is 1,000 Kg / cm
² is that the scale is destroyed by collision in the droplet flow area,
It is the lower limit pressure that can be removed. The upper limit of 10,000
Kg / cm ² is a limit value that leads to erosion of the metal base due to collision in the droplet flow region.

The surface of the wire after descaling with a water jet can be made finer in surface roughness as the inner diameter of the jet nozzle 5 is made smaller. For example, in order to obtain a surface of the same degree as the surface of the pickling material, it is possible to set the inner diameter of the injection nozzle 5 to 0.1 to 0.3 mmφ and the droplet diameter to the order of several tens of μm.

Next, the super-high pressure wet lubricant is externally supplied to the die-worked surface. The effect of increasing the pressure of the lubricant is to increase the viscosity η of the lubricant, the yield stress P of the wire and the lubrication. The difference (P-P _o ) from the initial pressure P _{1 of the} liquid is reduced to increase the lubrication film thickness h ₁ on the die-worked surface to prevent seizure and to increase the wire drawing speed. It is a thing. This relationship can be easily understood from the theoretical formula of the wedge effect, h _l = 3 · ηV cos α / (P−P _o ) sin α, which is derived from the Reynolds equation. Here, V is the wire drawing speed, and α is the die approach angle.

However, in the fluid lubrication in which the thickness of the lubricating film is increased, the surface roughness before wire drawing does not become so small and remains after wire drawing. It is also necessary to adjust the roughness, that is, the surface roughness after descaling. Further, the ultra-high pressure wet drawing has a great effect of preventing the temperature rise of the steel wire due to the heat generation during the drawing, and also prevents the strain aging embrittlement of the hard steel wire and extends the life of the die.

Further, the surface texture after wire drawing can be controlled by changing the supply pressure of the wet lubricant according to the application so that the boundary lubrication or the fluid lubrication can be arbitrarily selected. It is desirable to control the surface texture with the final die.

Next, water jet descaling is followed by ultrahigh pressure wet wire drawing in order to speed up the wire drawing speed by omitting the drying step, and to control the surface roughness after wire drawing. This is to widen the degree of freedom of operation so that the scaling condition and the wire drawing condition can be used. Next, in water jet descaling, the inner diameter d of the injection nozzle 5 with a perfect circular nozzle and good finishing accuracy,
The ratio 1 / d of the distance 1 from the tip of the nozzle to the wire is 100-
The reason why it is set to 800 will be described.

The applicant of the present invention has previously described that the descalable droplet flow region in FIG.
Water jet injection nozzle 1 as 00-800
The 1 / d that maximizes the dimensionless descaling amount (descaling width of wire rod circumferential direction / injection nozzle inner diameter) in a book is 400
Proposed to be ~ 600. However, in subsequent experiments, it was confirmed that the descalable l / d changes depending on the shape of the injection nozzle.

That is, in the case of a shape in which a perfect circular nozzle is notched or an elliptical nozzle, the droplet flow region is
It was confirmed that it was in the small range of 1 / d. From this fact, as the nozzle shape that can be put to practical use, a perfect circle, a perfect circle with a notch, and an ellipse are selected, and the maximum injection pressure 1
The l / d was set to 100 to 800, with some allowance for the limit value at which descaling can be performed at 10,000 Kg / cm ² .

Further, in a method of supplying a lubricant having an ultra-high pressure from the outside to perform forced lubrication wire drawing, when the first-stage diameter-reducing die has a role of a sealing die for forming a high-pressure chamber. In this case, considering the diameter variation of the drawn wire, the diameter reduction die is designed to allow a slight reduction in surface area so that the super-high pressure lubricating liquid does not explode.

Since the first stage seal die draws at atmospheric pressure, a dry lubricant that can increase the lubricating film pressure is desirable when higher speed wire drawing is required.

At this time, the heat generated by working with the seal die has a small surface reduction rate, so that the temperature rise of the steel wire is small and strain aging does not cause embrittlement.

Accordingly, in a multi-pass wire drawing in which a plurality of wires are arranged in series, a lubricant for dry wire drawing is used in the seal die of the first stage, and a wet wire drawing in which the diameter reduction dies of the second and subsequent stages is subjected to ultrahigh pressure. By supplying a lubricant for use in wire drawing to extend the life of the seal die, which is lubricated wire drawing at atmospheric pressure, and the dry lubricant adhering to the surface of the steel wire can also be used for wire drawing in the second and subsequent stages. It effectively exhibits a lubricating effect and brings about an effect of lowering the supply pressure of the wet lubricant. However, it is desirable to attach a discharge port for removing the entrained dry lubricant to the high pressure chamber 9 (FIG. 3).

[0028]

【Example】

Example 1 Examples of the present invention will be described below.

First, in order to determine the descaling conditions, the jet nozzle shape of the water jet was investigated. In the experiment, 16 injection nozzles 5 shown in FIG. 2 were attached to the Desuke nozzle support plate 11, and the wire rod fixing roller 12 was used.
4 nozzles which do not interfere with each other while preventing the wire rod 1 from swinging are selected. The material to be tested is JIS standard S54C,
Four types of SCM435, SWRH77A, and SWRCH8RL were used, and steel wire rods having a diameter of 3.0 to 8.3 mmφ were used. The transport speed is 100 m / min, the water jet injection pressure is 3000 Kg / cm ² , and the water amount is 5.0 l / m.
It was carried out under a constant condition of in.

As a result, as shown in Table 1, in any of the standards, the maximum of the dimensionless descaling amount is l /
As for d, the shape of the notched perfect circle was the closest, followed by the ellipse and then the perfect circle.

Here, the inner diameter d applied to the ellipse is an equivalent diameter equivalent to the nozzle cross-sectional area.

From the above experimental results, the descalable l / d is 100 to 800, and the nozzle shape that maximizes the dimensionless descaling amount is a perfect circle, and the l / d at that time is.
Is 500.

Although it has been confirmed that the dimensionless descaling amount is increased by retouching the wire material before the water jet injection, the present invention does not limit these descaling methods.

[0034]

[Table 1]

Next, as a method for descaling the entire circumference of the wire rod, as shown in FIG. 2, the number of nozzles is set so that the nozzles 5 at each stage arranged in the traveling direction of the wire rod can be uniformly descaled in the circumferential direction of the wire rod 1. And the mounting angle was changed and descaling was performed. As a result, as shown in Table 2, it was found that the descaling of the entire circumference was possible in any of the standards.

[0036]

[Table 2]

Example 2 After the wire rod on which the scale was generated in the hot rolling was cooled, the wet lubricating liquid, which was water jet descaled by the apparatus shown in FIG. 1 and subsequently increased in pressure, was supplied to the wire drawing die and drawn.

Descaling at this time is performed by using the apparatus shown in FIG. The test was conducted under the conditions of 1 (however, the conditions not shown in Table 3).

Next, as shown in FIG. 3, the wire drawing apparatus was a die system in which a high pressure chamber 9 was provided between a seal die 7 and a wire drawing die 8. As a lubricant, P-50 (phosphate ester type) manufactured by Kyoeisha Co., Ltd. was diluted to 5% with water, and the seal die was supplied at atmospheric pressure and the wire drawing die at an ultrahigh pressure.

The area reduction ratio was 5% for the sealing die and 15% for the wire drawing die, and continuous wire drawing was performed under the conditions of a supply voltage of 200 V, and the die temperature, the steel wire temperature after wire drawing, and the wire drawing load current were measured. It was measured.

The die temperature at this time was measured by attaching a thermocouple 3 mm above the bearing.

The wire temperature after wire drawing was measured with a contact surface thermometer.

As a result, as shown in Table 3, in the ultra-high pressure wet wire drawing performed after the water jet descaling, the pressure of the wet lubricant supplied to the wire drawing die is increased to promote the fluid lubrication. The frictional force is reduced, and the die surface and the wire rod surface temperature after wire drawing are lower than those of the conventional dry wire drawing by Coshin (manufactured by Kyoeisha Co., Ltd.). Further, even in the case of wet wire drawing, by increasing the supply pressure of the lubricating liquid, it is possible to improve the lubricity of dry wire drawing and reduce the load current.

[0044]

[Table 3]

Further, by setting the pressure of the lubricating liquid supplied to the wire drawing die in S45C to 3000 Kg / cm ² , the wire drawing speed can be increased as compared with the case of supplying at the atmospheric pressure.

When the supply pressure is further increased (supply pressure / yield stress), the limit of 0.7 to the limit at which the lubricating liquid explodes from the wire drawing die.
By setting it to around 0.8, it is expected that the frictional force will be lower than that of the conventional dry wire drawing, and the wire drawing speed will be further increased. When the supply pressure is increased in this way, the thickness of the lubricating film on the die-worked surface increases, and the surface roughness after wire drawing increases. Therefore, when a material having a low surface roughness is required, the object is achieved by lowering the supply pressure of the final die to bring it closer to boundary lubrication.

Further, by drying the steel wire after water jet descaling to dry seal the die and ultra high pressure wet lubrication for the wire drawing die, further high speed wire drawing becomes possible.

[0048]

EFFECTS OF THE INVENTION When descaling a steel wire before drawing, the high-density energy of the water jet is used without waste, clean descaling is performed in a short time, and then the ultra-high pressure wet lubricant is drawn. By supplying it to a die, improving lubricity and performing continuous wire drawing, high-speed wire drawing is possible over the conventional dry wire drawing.

Therefore, it is possible to prevent pollution at the time of descaling and wire drawing, improve working environment, and at the same time, greatly contribute to quality improvement and productivity improvement.

[Brief description of drawings]

FIG. 1 is a view showing a continuous wire drawing apparatus incorporating an ultrahigh pressure water jet descaling apparatus of the present invention and an apparatus for pressurizing an ultrahigh pressure wet lubricating liquid into a wire drawing die.

2A is a front view and FIG. 2B is a side view of a descaling device of the present invention.

FIG. 3 is a view showing a two-die wire drawing device adopted in the present invention.

[Explanation of symbols]

1 ... Steel wire 2 ... Supply stand 3 ... Straightening machine 4 ... Ultra-high pressure descaling device 5 ... Injection nozzle 6 ... 2 Die wire drawing device 7 ... Sealing die 8 ... Wire drawing die (pressure die) 9 ... High pressure chamber 10 ... Winding drum (capstan) 11 ... Desuke nozzle support plate 12 ... Wire rod fixing roller

Claims (3)

[Claims] 1. A scale is removed by colliding a water jet of an ultrahigh-pressure liquid having a pressure of 1,000 to 10,000 Kg / cm ² with a metal wire rod whose surface is oxidized to generate scale, and then an ultrahigh pressure is externally applied. The method for wire drawing of a metal wire rod, comprising: supplying the above-mentioned wet wire drawing lubricant to a high pressure chamber between dies for wire drawing. 2. In a method for removing scale by colliding a water jet of an ultra-high pressure liquid, the ratio (l / d) of the inner diameter d of the injection nozzle and the distance l from the nozzle tip to the metal wire is 100 to 800. The method for drawing a metal wire according to claim 1, wherein 3. In a plurality of wire drawing dies arranged in series, a dry wire drawing lubricant is added to a second diameter reducing die in a second order.
The wire drawing method for a metal wire rod according to claim 1, wherein a wire drawing process is performed by supplying an ultra-high pressure lubricant for wet wire drawing to the diameter-reducing dies after the first stage.