JP2001001030A - Wire drawing method of plating coated metal wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire drawing method of a coated metal wire effectively suppressing generation of a surface defect and hardly causing wire breaking. SOLUTION: In a method to continuously draw a plating coated metal wire, preliminary wire drawing is performed in order to smoothen the plated surface of the wire, successively, wet wire drawing is continuously performed by using plural dies, the wet wire is performed so that its first wire drawing uses a liquid lubricant having a viscosity higher than that of a second drawing and thereafter.

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 coated with plating, and more particularly, to the occurrence of surface defects due to poor lubrication in the final drawing step and the seizure of plating on a die. To effectively prevent the occurrence of disconnection and the like.

[0002]

2. Description of the Related Art Wire drawing performed for manufacturing a metal wire (for example, a steel filament used for a steel cord) from a metal wire (for example, a steel wire) is required in addition to finishing the metal wire to a predetermined wire diameter. This is an important step for adding mechanical properties.

[0003] Particularly, in the wire drawing in the final wire drawing process, a water-soluble lubricant containing an oil component and an extreme pressure component is used for a metal wire that has been subjected to patenting and further to plating,
It is common to carry out by a wet drawing method in which a plurality of dies are continuously drawn.

[0004]

However, when the plating-coated metal wire is drawn by the above-described method,
There are the following problems.

That is, in the case of a plating-coated metal wire,
(For example, brass plating)
An oxide layer (eg, ZnO) is likely to be formed on the plating surface, and such an oxide layer is generally needle-like and very hard, and tends to reduce lubricity during drawing.

Further, the surface of the wire before wire drawing has some irregularities (surface roughness). When plating is performed on the surface of the wire, the plating particles are affected by the surface of the wire (base). In order to take the precipitation distribution, the surface irregularities still exist after plating, and the plated wire having this surface irregularity is
When wire drawing is performed by the wet drawing method consistently as in the past, the lubricating film that coats the plating surface of the wire is
Thin (compared to the lubricating film obtained by dry drawing)
Since it is difficult to completely cover the entire uneven plating surface with the lubricant before drawing, the sharp protrusions on the plating surface cannot be coated with the lubricant, and they come into direct contact with the die. Due to poor lubrication, there is a possibility that the plating in such a portion may fall off, or the plating may seize on the dies due to direct contact with the dies.

[0007] When the wire is continuously drawn with the die having the plating seized, the surface of the steel wire becomes rough, and local embrittlement and minute defects are liable to occur. In the worst case, the wire breaks. May be reached.

An example of a means for solving such a problem is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-155532. According to the wet drawing method described in this publication, at least the first wire drawing It is stated that by relatively increasing the concentration of the lubricant used for the steel, the drawability and the like of the plated steel wire can be improved.

As in the wet drawing method described in the above publication,
When the concentration of the lubricant used in the second wire drawing is increased, the coverage of the uneven plating surface before the wire drawing is increased, but the thickness of the lubricating film itself is not so large. Cannot be sufficiently covered with the lubricating film, and therefore, it is difficult to solve the above-mentioned problems by such a method.

It is also possible to use a dry drawing method in which the entire plating surface of the wire material can be covered with a thick lubricating film. If the reduction in area is equal to or greater than the wire reduction rate in wire drawing, more specifically, if the wire (surface) that is the base of plating has a large deformation, the unprocessed plating film will deform the wire. Therefore, there is a problem that the unevenness of the plating surface of the wire tends to be further increased, and the plating is likely to fall off or clog in the subsequent wire drawing.

[0011] It is an object of the present invention to smooth the uneven plating surface before the wire drawing of the plating-coated metal wire, particularly in the final drawing step, and to perform the continuous wet drawing. Optimizing the concentration of the lubricant in the first wire drawing process effectively suppresses the occurrence of surface defects due to poor lubrication and the seizure of plating on the dies, and the occurrence of disconnections etc. It is an object of the present invention to provide a method for drawing a coated metal wire in which the occurrence of hardly occurs.

[0012]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is a method for continuously drawing a metal wire coated with a plating, and firstly, a preliminary method for smoothing the plating surface of the metal wire. Wire drawing is performed, and then, wet drawing is continuously performed using a plurality of dies.
This is a method for drawing a plating-coated metal wire, wherein the first drawing is performed using a liquid lubricant having a higher concentration than the second and subsequent drawing.

[0013] The "concentration of the liquid lubricant" as used herein specifically means the total concentration of the extreme pressure agent and the oil agent.

The preliminary drawing is preferably performed by dry drawing using a dry lubricant.
More preferably, it is 4%. Furthermore, it is preferable to use a sintered diamond die as the die for performing the first wire drawing, and it is more preferable that the area reduction rate in the first wire drawing is 2 to 15%. In addition, the concentration of the liquid lubricant used for the first wire drawing is
The concentration of the liquid lubricant used for the second and subsequent wire drawing
Preferably it is up to 10 times.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a main part of a typical continuous drawing apparatus for carrying out the drawing method of the present invention, and FIG. 2 is a drawing of the second and subsequent wet drawing performed after preliminary drawing. It is the figure which showed the structure of the 2nd wire drawing machine which performs wire working in detail, 1 is a wire drawing apparatus, 2 is a plating coating steel wire rod, 3 is a preliminary wire drawing machine, 4 is a wet type wire drawing machine. .

The drawing apparatus 1 shown in FIG.
(Cu + Zn) Brass plating) is a device for manufacturing a plated coated steel wire by continuously and finally drawing a steel wire 2 having been subjected to (Cu + Zn) brass plating, and for smoothing a plating surface of the steel wire 2. It has a preliminary wire drawing machine 3 and a wet wire drawing machine 4 that performs continuous wire drawing using a plurality of dies.

The preliminary wire drawing machine 3 is arranged for the purpose of smoothing out irregularities on the surface of the wire after plating. As the preliminary wire drawing machine 3, for example, a dry wire drawing machine is preferably used. . That is, a dry wire drawing machine can form a thick lubricating film on the surface of a plated wire, and good lubricity can be obtained regardless of the presence of an oxide film which is easily formed after plating and before wire drawing. is there.

The wet wire drawing machine 4 includes a first wire drawing machine 5 having a unit bus 7 and one die 8, as shown in FIG. 2, a unit bus 9, and a plurality of dies 10a, 10b,. And a second wire drawing machine 6 having capstans 11a, 11b,-.

The first wire drawing machine 5 is a wire drawing machine for first performing wet wire drawing after preliminary wire drawing, and includes a unit bus 7 having a unit bus 9 of a second wire drawing machine 6. A liquid lubricating liquid containing a higher concentration of the lubricant is filled.

The concentration of the liquid lubricant in the unit bath 7 of the first wire drawing machine 5 is preferably 2 to 10 times the concentration of the liquid lubricant in the unit bath 9 of the second wire drawing machine 6.

As a liquid lubricant, an extreme pressure agent (phosphate,
It is preferable to use a water-soluble (emulsion type) in which water is added to a lubricant mainly containing an alkyl phosphate (eg, an alkyl phosphate) or an oil agent (eg, a fatty acid salt).

The dies 8 of the first wire drawing machine 5 include:
It is preferable to use a sintered diamond die that can reduce surface irregularities.

The second wire drawing machine 6 has substantially the same configuration as the wet wire drawing machine used in the usual final drawing process (FIG. 2).

In the wire drawing method of the present invention, particularly in the final wire drawing step, the surface of the plated surface is smoothed before the wire drawing of the plating-coated metal wire is performed, and then the wet wire drawing is performed continuously. The first is to optimize the concentration of the lubricant in the first wire drawing process, more specifically,
Pre-drawing for smoothing the plating surface of the metal wire is performed, and then wet drawing is continuously performed using a plurality of dies, and the wet drawing is performed by the first drawing process. The second and subsequent drawing operations are performed using a liquid lubricant having a higher concentration than that of the second and subsequent drawing operations, whereby the occurrence of surface defects can be effectively suppressed and the occurrence of disconnection can be prevented.

More specifically, by performing the pre-drawing, the plating surface of the metal wire can be smoothed, so that the coated wire used for the subsequent wet drawing can be used. And a surface state excellent in processability can be provided.

The “smoothing of the plating surface” in the preliminary drawing described above specifically means that particularly the convex portions of the irregularities on the plating surface are hardly deformed without substantially deforming the plating base (wire material). This means that the surface is leveled, and it is preferable that the surface roughness has a certain size. The reason for this is that in the subsequent wet drawing, it is easier for the lubricant to coat the plated surface if there is a certain degree of fine irregularities.

The pre-drawing is preferably performed by dry drawing using a dry lubricant. In this case, the reduction in area is equal to or greater than the reduction in normal drawing. (> 4%), the metal wire itself, which is the base of the plating, is greatly deformed, and the surface unevenness of the base itself tends to increase, and accordingly, the unevenness of the plating surface also increases. Plating fallout and plating clogging are likely to occur.

Therefore, it is preferable that the area reduction rate in the preliminary wire drawing is smaller than the area reduction rate in the normal wire drawing.
More preferably, it is 1 to 4%.

Next, after the preliminary drawing, wet drawing is continuously performed using a plurality of dies, and the first wire drawing of the wet drawing substantially causes the plated coated wire itself to be substantially drawn. However, in the present invention, the wet drawing is performed in a short time by performing the first drawing by using a liquid lubricant having a higher concentration than the second and subsequent drawing. The surface oxide can be completely removed by plating, and the plating has a new surface due to the first wire drawing, and the new surface is a smooth surface with appropriate irregularities. The whole can be covered sufficiently.

By increasing the lubricity in the first wire drawing, the lubricity in the second and subsequent wire drawing is also improved. As a result, the surface of the steel wire after the final wire drawing is processed. The generation of defects and the seizure of plating on dies can be effectively suppressed.

Further, if a sintered diamond die is used as the die for performing the first wire drawing, the unevenness of the plating surface of the wire can be reduced, and the circumferential direction of the metal wire by the second and subsequent wire drawing can be reduced. Therefore, it is possible to effectively suppress the occurrence of a portion where processing is concentrated locally (for example, a portion where a convex portion existing on the surface is largely processed by the next die).

In wet drawing, a test was performed using a high-concentration lubricant even in the second and subsequent drawing processes.
When wire drawing using a high-concentration lubricant is performed later in the wire drawing process, specifically, when wire drawing is performed in the second or subsequent wire drawing, after the final wire drawing The residual ratio of the extreme pressure agent on the surface of the plating-coated metal wire becomes considerably large. When such a metal wire is used, for example, as a steel cord of a belt which is a reinforcing member of a tire, sufficient adhesion to rubber is required. Therefore, in the present invention, the concentration of the lubricant is increased only at the time of the first wire drawing in the wet wire drawing.

Further, the area reduction rate in the first wire drawing is preferably 2 to 15%, more preferably 5%.
~ 10%.

In addition, the concentration of the liquid lubricant used for the first wire drawing is preferably 2 to 10 times the concentration of the liquid lubricant used for the second and subsequent wire drawing.

The above is only an example of the embodiment of the present invention, and various changes can be made within the scope of the claims.

[0036]

EXAMPLE Next, a high-carbon steel wire rod (C: 0.82 wt%, brass plating adhesion amount: about 4.5 g / kg, wire diameter) subjected to patenting and brass (brass) plating by the wire drawing method of the present invention. : 1.47mm), producing a steel filament with a wire diameter of 0.19mm, a tensile strength at 0.19φ of about 4065MPa, and a length of about 450,000m (about 100kg in weight),
The performance has been evaluated and will be described below.

In Examples 1 to 3, wire drawing was performed using the wire drawing apparatus shown in FIGS. 1 and 2. Preliminary wire drawing was performed using a dry wire drawing machine, and Fcomet B10 (Azuka Corporation) was used as a dry lubricant. Dies) and tungsten carbide (WC)
Dice. Thereafter, wet drawing was performed. For wet wire drawing, the first wire drawing is performed using a sintered diamond die as a die, and for the second and subsequent wire drawing, wire drawing is performed using a total of 21 dies. Each die was a WC die, and ADM (Rhone Poulin) was used as a wet lubricant. This wire drawing is one pass for preliminary wire drawing, one pass for the first wire drawing in wet wire drawing, and 21 passes for the second and subsequent wire drawing.
Performed in three passes.

The area reduction rate (%) in the preliminary drawing, the area reduction rate (%) and the lubricant concentration (%) in the first drawing in wet drawing, and the total Table 1 shows the area reduction rate and the concentration (%) of the wet lubricant.

[0039]

[Table 1]

For reference, instead of the conventional example 1 in which a steel filament was manufactured only by wet drawing (total 23 passes) from the beginning without performing preliminary drawing, instead of performing the first drawing in wet drawing. Comparative Example 1 in which a steel filament was manufactured under the same drawing conditions as in Example 1 except that the steel filament was immersed in a wet lubricant liquid, and the wet lubricant used in the first drawing process in the wet drawing. Density to normal density (8-10
%) Of Comparative Example 2 in which a steel filament was manufactured under the same drawing conditions as in Example 1 except that
It was also described in.

(Evaluation of Performance) For each of the above-mentioned samples, a die for preliminary drawing, a die for first drawing in wet drawing, and a sample after the second drawing after completion of the above drawing. In addition to measuring the presence or absence of plating seizure on the dies to be performed and the surface roughness of the plated coated steel wire immediately after passing through each of the dies, the surface properties and mechanical properties (toughness) of the steel filament were measured. , The performance was evaluated.

(1) Measurement of the presence or absence of plating seizure on each die and measurement of the surface roughness of the plated steel wire at the position immediately after passing through each of the dice. After the line, visually and by SEM observation and measurement, "none",
The evaluation was made in four stages of “small”, “medium”, and “large”. In the present invention, "none" and "small" were regarded as acceptable levels. In addition, the surface roughness of the plated coated steel wire was measured by a surface roughness measuring device (trade name: Tarisurf),
The evaluation was made on a three-point scale of "medium" and "large". In the present invention, "none" and "small" were regarded as acceptable levels. Table 1 shows these results.

(2) Evaluation of Surface Properties of Steel Filaments The surface properties of steel filaments were measured by measuring the degree of plating falling off after completion of wire drawing and the concentration of Cu and Zn by plating analysis (using fluorescent X-rays). The weight (adhesion amount) was converted from the measured value, and the weight was evaluated. Table 1 shows the evaluation results. In addition, the numerical values in Table 1 are shown by an index ratio with Conventional Example 1 being 100, and a smaller numerical value means that the surface properties of the steel filament are better.

(3) Evaluation of Mechanical Properties (Toughness) of Steel Filament The toughness of the steel filament was determined by measuring the hooking load.
The quality was evaluated from the measured values. The hooking load is a result of measuring the cutting load by bending two samples of 300 mm in length in a U shape and crossing each other, fixing the free ends, and applying a traction force in that state. . Table 2 shows the evaluation results. The numerical values in Table 2 are based on the numerical value represented by hooking load / cutting load × 100 (%), and
Is shown as an index ratio with 100 as the value. The larger the value, the better the toughness of the steel filament. The presence or absence of disconnection was also examined, and the results are also shown in Table 1. In addition, the numerical values in Table 1 are indicated by the disconnection index ratio with the value of Example 1 being 100, and the smaller the value, the smaller the occurrence of disconnection.

From the evaluation results shown in Table 1, in each of Examples 1 to 3, plating seizure in each die was suppressed as compared with Conventional Example 1, and the surface properties of the wire after drawing were good. And the toughness was excellent, and no disconnection occurred. on the other hand,
In Conventional Example 1 and Comparative Example 1, plating seizure on the dies was remarkable, the disconnection indices were 150% and 120%, respectively, and disconnection occurred relatively frequently. Comparative Example 2
In the case of the first wire drawing in wet wire drawing, plating seizure and the surface roughness of the steel wire were inferior to the acceptable levels.

[0046]

According to the wire drawing method of the present invention, it is possible to continuously produce a metal wire from a plating-coated metal wire with less occurrence of surface defects and hardly causing disconnection. In particular, the present invention can remarkably exert the above-mentioned effects by applying to a plated metal wire having a relatively large diameter before drawing (specifically, 1 mm or more), and has a tensile strength of not less than 1 mm. Suitable for manufacturing steel wire of 4000MPa or more.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a typical drawing apparatus for carrying out a drawing method of the present invention.

FIG. 2 is a detailed view of a portion of a wire drawing device that performs second and subsequent wire drawing processes of wet wire drawing performed after preliminary wire drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire drawing apparatus 2 Plating-coated metal wire material 3 Preliminary wire drawing machine 4 Wet wire drawing machine 5 First wire drawing machine 6 Second wire drawing machine 7 Unit bus 8 Die 9 Unit bus 10a, 10b,-Dice 11a, 11b, -Capstan 12 dice

Claims (6)

[Claims] 1. A method for continuously drawing a plating-coated metal wire, wherein a preliminary drawing for smoothing a plating surface of the metal wire is first performed, and then a continuous drawing is performed using a plurality of dies. Wherein the first wire drawing is performed using a liquid lubricant having a higher concentration than the second and subsequent wire drawing, and the wet wire drawing is performed by using a wet coating method. Wire drawing method. 2. The drawing method according to claim 1, wherein the preliminary drawing is dry drawing using a dry lubricant. 3. The drawing method according to claim 1, wherein a reduction in area in the preliminary drawing is 1 to 4%. 4. The wire drawing method according to claim 1, wherein a sintered diamond die is used as a die for performing the first wire drawing. 5. The area reduction rate in the first wire drawing is 2
The wire drawing method according to any one of claims 1 to 4, wherein the amount is 15% to 15%. 6. The concentration of the liquid lubricant used in the first drawing operation is 2 to 10 times the concentration of the liquid lubricant used in the second and subsequent drawing operations. Or the wire drawing method according to item 1.