JP2003048014A - Multi-die and drawing method of metal wire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a steel wire which has higher strength even in the steel of conventional composition and is excellent in twisting property. SOLUTION: This die is a die for performing wire drawing by drawing a metal wire and three and more dies are made into structure by which cooling medium is supplied and housed in a die box. Preferably, the reduction of area of each die is approximately equalized. In this drawing method, wire drawing is performed by applying this multi-die to any stage of a continuous wire drawing process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die used for wire drawing and a wire drawing method used for manufacturing ultrafine steel wires such as tire cords, belt cords, hose wires and saw wires.

[0002]

2. Description of the Related Art Generally, high carbon steel ultrafine wire such as steel cord is usually hot-rolled, if necessary, and then conditioned and cooled to obtain a wire rod having a diameter of 4.0 to 5.5 mm after primary wire drawing. It is manufactured by performing a final patenting treatment, and then a brass plating treatment and a final wet drawing process. Most of such ultra-fine steel wires are used as steel cords in a state in which a twisted wire process such as two-ply twist and five-ply twist is applied. Therefore, these high carbon ultrafine steel wires have characteristics such as higher strength than (1), (2) excellent high-speed drawability, and (3) excellent high-speed twistability. Must.

For this reason, high-quality steel materials have conventionally been developed to meet these demands. For example, JP-A-60
In JP-A-204865, the Mn content is regulated to less than 0.3% to suppress the generation of a supercooled structure after lead patenting and regulate the content of C, Si, Mn, etc. An ultrafine wire and a high carbon steel wire material for a steel cord, which have high strength and high toughness with little breakage at time, are disclosed. Further, in JP-A-63-24046, Si is disclosed.
There is disclosed a wire material for high toughness and high ductility ultrafine wire in which the tensile strength of the lead patented material is increased by setting the content to be 1.00% or more and the wire drawing work ratio is reduced.

Further, as a wire drawing method for improving the twisting property, Japanese Patent Application Laid-Open No. 11-319933 discloses a triple die wire drawing method, but a large reduction in area on the entry side is adopted. However, there is a problem in that the effect of heat generation is large and a sufficient improvement effect cannot be obtained when the wire drawing speed is increased.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a die and a wire drawing method which enable production with higher strength and excellent twisting characteristics without particularly changing the steel composition.

[0006]

The present invention has been made to solve the above problems, and the gist thereof is as follows.

(1) A die for drawing a metal wire by pulling it out, and 3 dies are provided in a die box.
A multi-die having a structure in which at least one sheet is accommodated and a cooling medium for cooling the metal wire is provided between the dies.

(2) The multi-die as set forth in (1), wherein the die reduction ratios of the dice housed in the die box are substantially equal.

(3) A metal wire which is characterized in that the multi-die described in (1) or (2) is used as a die for any one of the continuous wire drawing steps to draw a metal wire. Wire drawing method.

(4) A metal characterized by using the multi-die according to (1) or (2) as a finishing die and drawing a metal wire at a wire drawing speed of 300 m / min or more. How to draw a wire.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In order to improve the strength of a wire drawing wire, increasing the amount of wire drawing is the simplest method. However, it is generally said that as the strength increases, the ductility decreases, and in particular, in the case of wire drawing of high carbon steel, the ductility tends to decrease as the wire drawing speed increases. The present inventors have noticed that, when manufacturing a wire having high strength, increasing the wire drawing speed raises the temperature of the wire after wire drawing. When the wire temperature rises, delamination easily occurs. As a method of suppressing heat generation during wire drawing, a method of cooling with water after leaving the finishing die is known. However, in the case of continuous drawing of extra fine wire, the finishing speed is very fast at 300 m / min or more, and there is a problem of drying after cooling. Therefore, a method of cooling after leaving the finishing die At present, it is difficult to collect.

As a result of studying a method of sufficiently removing the working heat in the die, the inventors of the present invention corresponded to the area reduction rate by this die with respect to the step which was conventionally surface-reduced by one die. We have developed a technology to secure the surface reduction rate by dividing it with three or more dies and to cool the steel wire with a liquid lubricant between the dies. That is, a multi-die having a structure in which three or more dice are housed in a die box and a cooling medium is supplied between the dice to cool the wire rod.

FIG. 1 shows a schematic sectional view of the structure of the multi-die of the present invention. 1A is a front view and FIG. 1B is a sectional view.

The multi-die of the present invention is basically composed of a die box 3 for accommodating the dice 2 and the intermediate presser 4, dies 2a, 2b and 2c accommodated therein, and intermediate pressers 4a and 4b. It The die box 3 is composed of an inlet die presser 5 for fixing the die on the steel wire inlet side, an outlet die presser 6 for fixing the die on the steel wire outlet side, and a die cylinder 7 for accommodating the above die. Tube 7
The cooling lubricant supply holes 8 and the cooling lubricant discharge holes 10 are provided on the outer peripheral portion of the substantially corresponding positions where the intermediate pressers 4a and 4b are arranged. A cooling lubricant supply pipe 9 is attached to the cooling lubricant supply hole by welding or spiraling.

Further, metal wire passage holes 11 ', 11''are provided at the centers of the entrance die presser 5 and the exit die presser 6 concentrically with the axial center of the die cylinder. The exit side die presser 6 is usually fixed to the exit side of the die cylinder 7 by welding or a spiral, and the entrance side die presser 5 is detachably fixed to the entrance side of the die cylinder by a spiral.

Inside the die cylinder 7 of the die box 3, a plurality of dies, in this example, three dies, 2a,
2b and 2c, and an intermediate presser 4a and an intermediate presser 4b, which are located between these dies and hold a space between the dies, are housed.

This intermediate presser 4, (same for 4a and 4b)
Relates to a cooling means for the metal wire in the multi-die of the present invention in association with the supply hole for the cooling lubricant of the die box.

FIG. 2 is a front view of the intermediate presser 4 (the same applies to 4a and 4b). The intermediate presser is a short columnar member having an outer diameter substantially the same as the outer diameter of the die, and a metal wire passage hole 11 for allowing a metal wire to pass therethrough is provided in the axial center thereof. An annular groove 12 is formed on the outer peripheral side surface of the cylindrical portion of the intermediate presser.
A plurality of communicating holes 13 communicating with the metal wire passing hole 11 are provided at the bottom of the annular groove 12.

These communication holes are provided for efficient circulation of the cooling lubricant. Dice box,
For the intermediate presser and the like, a material having strength and corrosion resistance that can be used in a normal wire drawing process, such as steel and stainless steel, is used.

In the die cylinder of the die box, the dies 2a, 2 are placed so that the intermediate pressers 4a, 4b are adjacent to the dies.
After inserting b, 2c and the intermediate pressers 4a, 4b, the entrance die presser is spirally closed in the die cylinder to form the multi-die 1. In addition, the metal wire passage hole 11 of the intermediate presser, the die side of the die box and the die side of the die presser 5,
The metal wire passage holes 11 'and 11''of 6 are arranged substantially concentrically with the holes of the die.

In the drawing process, the steel wire is introduced into the multi-die from the right side (the direction of the arrow) in FIG. 1 (b), and the die 2a, the intermediate presser 4a, the die 2b, the intermediate presser 4b,
It passes through the dies 2c in this order, and is subjected to surface reduction processing by each die. At this time, the cooling lubricant is supplied from the cooling lubricant supply pipe 9 into the die box through the cooling lubricant supply hole 8. The cooling lubricant is supplied into the metal wire passage hole 11 through the communication hole 13 via the annular groove 12 provided in the intermediate presser 4. The steel wire processed by the die and generating heat is immediately cooled in the metal wire passage hole to prevent the temperature from rising. After cooling the metal wire, the cooling lubricant is discharged through the cooling lubricants 10 and 10 of the die box.

Next, FIG. 3 shows the temperature of the steel wire at the die exit side when wire drawing is performed by changing the wire drawing speed using a multi-die in which the dies are assembled in this manner.

Incidentally, in FIG. 3, in the wire drawing step, the area reduction rate in the case of wire drawing with one die is conventionally used as a base, and this is described as "no division".

In the die box of the present invention, the case where the conventional area reduction rate is obtained by two dies is "2".
“Divided” is referred to as “divided into three” when it is obtained by three dice.

As can be seen from FIG. 3, the required area reduction rate, which was conventionally obtained with a single die, is obtained with a plurality of divided dies, whereby the temperature of the steel wire is lowered and the wire drawing speed is increased. However, the effect of suppressing the rise in the temperature of the steel wire can be obtained.

This effect is obtained by dividing the die into two or more pieces, that is, by using a die box composed of two or more dies by dividing the area reduction rate in place of the conventional one die. However, when the surface reduction rate of one die in the die box increases, the amount of heat generated increases, so the surface reduction rate of one die is preferably 5% or less.

On the other hand, conventionally, it is preferable that the area reduction rate in the case of wire drawing in one pass by one die without dividing as described above is 12% or more.

This is because if the area reduction rate is small, the processing does not reach the central portion of the steel wire, which may cause a break in the cuppy. The same applies to the multi-die of the present invention, and the area reduction rate of one pass of the multi-die is 1
It is preferably at least 2%.

From the above, the number of dies forming the multi-die of the present invention is set to 3 or more.

The number of dies forming each multi-die is based on the area reduction ratio required in the wire drawing process, and this is divided into three or more dies, that is, the area reduction of one die. It may be determined so that the rate is 5% or less, but in the multi-die of the present invention, it is preferable that the area reduction rate of each die be substantially equal. This is because if there is a large difference in the area reduction rate of each die forming the multi-die, the heat generation status changes for each die exit side, and the heat generating steel wire temperature and cooling status fluctuate, which is not preferable for the material. is there. The variation of the area reduction rate between the dies forming the multi-die is within 50%, preferably within 20%, and more preferably within 10%.

The multi-die of the present invention can be used at any wire drawing stage, but is most effectively used at the finishing die stage.

This is because a rise in the temperature of the steel wire can be suppressed to a minimum and a high working rate can be imparted. When a wire having higher strength is to be obtained, the finishing die is used as the multi-die of the present invention. It is effective to do.

Further, as can be seen from FIG. 2, by using the multi-die of the present invention, the die can be drawn at a drawing speed of 3%.
Even when it is set to 00 m / min, the rise in the temperature of the steel wire can be suppressed to a low level, and a steel wire with higher strength can be suitably manufactured with high production efficiency. That is, in the conventional method, when the wire drawing speed is 300 m / min or more, the heat generation is large and the embrittlement occurs, and delamination occurs.

[0034]

EXAMPLES The effects of the present invention will be described below with reference to examples.

A 92 Acr 5.5 mm wire having the composition shown in Table 1 was formed into a 1.85 mm wire by wire drawing and intermediate patenting. As a patenting treatment for this wire, after heating it to 950 ° C., 575
A pearlite steel wire was obtained by immersing in a lead bath at ℃. The mechanical properties at this time are shown in Table 2.

[0036]

[Table 1]

[0037]

[Table 2]

Next, the wire is brass-plated, and a dipping condition is variously changed by using a continuous wire drawing machine of a total immersion type (a method of immersing the whole die box in the lubricant) with a water-soluble lubricant. Change to 600mm / mi on 0.3mm wire
Wire drawing was performed at a finishing speed of n. The conditions are shown in Table 3. In addition, the mechanical properties of the drawn wire were investigated, and the results are shown in Table 4.

[0039]

[Table 3]

[0040]

[Table 4]

The multi-die of the present invention is applied to a pass corresponding to one finishing die, and the surface reduction rate of each die constituting the multi-die is adjusted to 5% or less.
In No. 2, although the wire was drawn at a high speed of 600 m / min, delamination did not occur in the twist test of the wire after wire drawing.

On the other hand, a multi-die consisting of three or more dies according to the present invention was applied to a pass corresponding to one finishing die, and the area reduction rate of the first die of the multi-die exceeded 5%. In Comparative Example-1, delamination occurred in the twist test of the wire after wire drawing.

Also, a multi-die consisting of two or more dies is applied to a pass corresponding to one finishing die,
In Comparative Example-2, in which the die reduction ratio of the first pass of the multi-die was more than 5%, the number of dice divisions was small, and the die reduction ratio of one die was more than 5%, which was large. Delamination occurred in the twist test of the wire after the wire.

In the multi-die of the present invention, the area reduction rate of each die constituting the multi-die is properly set, and the cooling between the dies is good, so that a good machine is achieved despite high-speed wire drawing. A wire having specific properties can be obtained.

[0045]

EFFECTS OF THE INVENTION A wire having high strength and excellent ductility can be easily obtained.

[Brief description of drawings]

1A and 1B are schematic diagrams showing a configuration of a multi-die of the present invention, FIG. 1A is a front view, and FIG. 1B is a sectional view.

FIG. 2 is a front view showing the shape of the intermediate presser of the multi-die of the present invention.

FIG. 3 is a diagram showing a relationship between a die split state and a steel wire temperature at a die exit side in the present invention.

[Explanation of symbols]

1 ... Multi-Dice 2, 2a, 2b, 2c ... Dice 3 ... Dice box 4, 4a, 4b ... Intermediate presser 5 ... Entry side die presser 6 ... Pressing die on the delivery side 7 ... Dice tube 8 ... Coolant supply hole 9 ... Lubricant supply pipe for cooling 10 ... Coolant lubricant discharge hole 11, 11 ', 11 "... Steel wire passage hole 12 ... Annular groove 13 ... Communication hole

Continued front page    (72) Inventor Masaru Sasaki             1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel shares             Company Kimitsu Works (72) Inventor Masatoshi Ogata             1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel shares             Company Kimitsu Works (72) Inventor Ryuji Ogata             1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel shares             Company Kimitsu Works (72) Inventor Toshiharu Sugawara             1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel shares             Company Kimitsu Works F-term (reference) 4E096 EA02 EA13 FA02 FA12 HA23                       KA01 KA05

Claims (4)

[Claims] 1. A die for drawing a metal wire by drawing, wherein three or more dies are housed in a die box, and a cooling medium for cooling the metal wire is supplied between the dies. Multi-die that has a structure that 2. The multi-die according to claim 1, wherein the die reduction ratios of the respective dies housed in the die box are substantially equal to each other. 3. A metal wire, comprising: drawing a metal wire by using the multi-die according to claim 1 or 2 as a die for a wire drawing process in any one of continuous wire drawing processes. Drawing method. 4. A metal wire, comprising: using the multi-die according to claim 1 or 2 as a finishing die, and drawing the metal wire at a wire drawing speed of 300 m / min or more. Drawing method.