JPH0785801B2 - Manufacturing method of thin wire - Google Patents

Description

The present invention relates to a method for producing a thin wire having a diameter of 5 mm or less.

[Prior Art] To manufacture fine wires made of metal such as steel with a diameter of 5 mm or less, billets obtained by slab rolling or continuous casting are sequentially rolled by a rough rolling mill group, an intermediate rolling mill and a finishing rolling mill group. This is done by producing a wire rod having a circular cross section with a diameter of 5.5 mm or more, and further drawing this wire rod to gradually reduce its diameter.

There are the following four methods for gradually reducing the outer diameter. First, as a first method, as shown in FIG. 5, the tip end portion of the wire rod of a hole die 51 having a circular hole 52 through which the wire rod is inserted is inserted, and the wire is pulled by a winder provided on the outlet side. There is a method ("Plasticity and Machining", Vol.14, No.152, P733-P755) of wire drawing by repeatedly performing the drawing and wire drawing processes for a plurality of hole dies having different diameters of the hole type. As a second method, as shown in FIG. 6, a pair of roller pairs 6 in which hole-shaped forming grooves 61a, 62a for inserting a wire into the opposing peripheral surface portions are formed.
In the same way as before, insert the tip of the wire into the hole die 63 of the roller die with 1,62 installed oppositely, and pull out the wire with the winder installed on the exit side to draw the wire. There is a method of repeatedly performing wire drawing for a plurality of different roller dies (see above). As a third method, four cylindrical flat rolls 71, 72, 73, 74 around the pass line as shown in FIG.
A plurality of rolling mills configured to drive at least one roll or more, in the illustrated example, the roll 73, by forming a rectangular hole die 75 on four circumferential surfaces. There is a method (Japanese Patent Laid-Open No. 58-303) in which the wire rods are installed differently in tandem and the wire rods are sequentially fed by each rolling mill and continuously rolled. As a fourth method, as shown in FIG. 8, three hole type rolls 81, 82, 83 are arranged around the pass line, and a substantially circular hole type 84 is formed on the three circumferential surfaces, and each roll is driven. And a rolling mill configured to drive three rolls by arranging three flat rolls around the pass line to form a substantially triangular hole shape on the three circumferential surfaces. A method in which wires are installed alternately and in a plurality of tandems, and the hole die sizes are sequentially changed, and the wire rods are sequentially rolled by each rolling mill while changing the shape and dimensions of the cross section A as shown in FIG. 9 (Wire Ass
ociation International 52nd Annual Convention in P
ittsburgh, PA, on October 17-21, 1982 and Wire Indust
ry, April 1983).

Further, the following method has been proposed as a method for producing a wire rod or a rod from a billet (Japanese Patent Laid-Open No. 50-140354). In this method, as shown in FIG. 10, four rolling mills 91, 92, 93, 94 are arranged around the pass line to form a plurality of rolling mills having a substantially square-shaped rolling mill 95 on four circumferential surfaces. , Which are installed in tandem by sequentially changing the size of the hole die, are dimensions for continuously rolling the material while sending it by each rolling mill, and the final diameter is for wire rods or rods with a diameter of 5.5 mm or more, as a product target, It cannot be applied to the production of thin wire rods with a diameter of 5.0 mm or less.

[Problems to be Solved by the Invention]

In the case of the first method or the second method, in addition to problems such as disconnection during wire drawing, a winding machine is required for each die, which makes the equipment complicated and long. In addition, processing speed and processing efficiency are reduced. In addition, when the material of the wire drawing material is high carbon steel, it may be necessary to perform annealing in the middle of the wire drawing process, and the wire drawing process becomes discontinuous, resulting in reduced productivity and production costs. There is a problem that is high.

In the case of the third method, since the rolling face has the same pressure lower surface position in the adjacent rolling mills, the material does not fall down, but the corner portion of the rolled material rolled by the rectangular hole roll is rolled. In some cases, it may become impossible to continue rolling due to being caught in the gaps on the peripheral surface. In the case of the fourth method, the cross-sectional shape of the material to be rolled changes to a circular or substantially triangular shape, so the roundness of the product is 10 mm in diameter. Is about ± 0.3 mm, which is considerably worse than that of the first and second methods ± 0.15 mm, and the cross-sectional shape of the wire-drawn material during wire drawing is always circular. Compared with the method, the degree of freedom of product dimension is restricted. Furthermore, in the case of the third and fourth methods, since the material to be rolled is fed in the direction stretched by rolling, there is a risk that its axis may deviate from the pass line of the next rolling mill. A guide is required between them, and surface defects are likely to occur on the material to be rolled due to contact with the installed guide, and special design is also required for the design of the guide to prevent surface defects.

Further, in the case of the fourth method of rolling with a roll or the method shown in FIG. 10, when the ratio of the roll diameter to the diameter of the material to be rolled is large, the material to be rolled easily falls between the rolls and the material is twisted. Once a fall occurs, it does not return to its original state, and the rolling reduction is different from the designed pass schedule, so that the roll gap is caught and the rolling cannot be continued. When the roll diameter is reduced in order to prevent this fall, the roll axis inevitably becomes thin, and it is difficult to select a bearing that can withstand high speed rolling.

Therefore, although the productivity is low at present, the wire drawing process using a die is mainly used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of producing, by rolling, a small-diameter wire rod having an arbitrary size and having good quality without surface defects and the like with high production efficiency.

[Means for Solving the Problems]

The method for producing a small-diameter wire rod of the present invention is a method for producing a small-diameter wire rod having a smaller diameter by drawing and rolling a wire rod by a rolling mill group in which a plurality of rolling mills are installed in tandem. Four hole-shaped rolls are arranged around the line, and those having a substantially circular hole-type are used. Also, adjacent rolling mills do not overlap the unconstrained portions of the roll-shaped holes with respect to the wire rod. It is characterized in that rolls are arranged in the rolls, the total cross-section reduction rate is set to 40% or more, the rolls are stretch-rolled, and the small-diameter wire rod is wound on the exit side of the rolling mill group.

[Action]

According to the present invention, a rolling mill in which four rolls each having a substantially circular hole shape are arranged around the pass line is arranged in tandem, and each adjacent rolling machine is a non-high speed portion for a wire rod according to each roll hole shape. Since the rolls are arranged so that they do not overlap with each other, it is possible to obtain a high-quality wire diameter wire rod having high dimensional accuracy and roundness. That is, by using four rolls, centripetal pressure is exerted in the non-restraint portion as in the restraint portion, and the rolls are uniformly pressed in the radial direction. is there. In addition, since a centripetal rolling force acts on both the constrained part and the unconstrained part, even in the rolling mill group that is a substantially circular hole type series, 15% per rolling mill
It is possible to reduce the high-pressure reduction rate to a certain degree, and it is possible to achieve a total cross-section reduction rate of 40% or more with the number of rolling mills in consideration of economy.

〔Example〕

The present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic side view showing an implementation state of the method of the present invention, in which 1 indicates a rewinder. The rewinding machine 1 has a wire W having a diameter of 5.5 mm or more and having a circular cross section, which is manufactured by sequentially rolling a billet obtained by slab rolling or continuous casting in a rough rolling mill group, an intermediate and finish rolling mill group. It is wound and the wire W can be unwound by pulling one end side.

The unwound wire W is guided to the entrance guide 2 and then sent to the high-frequency heating furnace 3 to be heated to a predetermined temperature, and the motors 4 are moved to low speeds such that the wire advances at a speed of 0.1 m / sec, for example. After being passed through the rolling mill group 5 and taken up by the winding machine, it is driven at a high speed and gradually reduced in diameter while passing through it by the rolling mill group. It becomes a small-diameter wire SW, and then is wound up by the winder 6 via the guide 6a.

The rolling mill group 5 includes a plurality of rolling mills having four circular rolls arranged around the pass line to form the circular circular rolls, which are installed in tandem with substantially the same configuration.

The configuration of the first rolling mill at the entrance end of the rolling mill group 5 will be described with reference to FIG. 2 (front view). An octagonal housing when viewed from the front
10 has vertical and horizontal cross-shaped holes extending in four directions orthogonal to each other from the center, and hole-shaped rolls 11, 12, 13, 14 are respectively provided at the four tips of the holes at the shafts on both ends thereof. 11a, 12a, 13
The a and 14a are rotatably inserted into a bearing hole formed on the wall surface in the longitudinal direction of the hole. In other words, each roll is a double-sided type.

The spur gear 8, 8 is provided at one end of the shaft 13a and on the other end of the shaft 14a, respectively.
9 are concentrically provided, and both spur gears 8 and 9 mesh with each other. One end of the shaft 13a is connected to the rotary shaft of the motor 4 via a transmission mechanism (not shown), and the rolls 13 and 14 are rotated in opposite directions.

The peripheral surfaces of the rolls 11, 12, 13, 14 have hole forming grooves 11b, 12b, 13b, 14b at the center of the roll axial direction, and the radii of the roll ends are set on both sides of the groove forming grooves. Is formed to be smaller than the radius of the. Since this inclined surface is tilted at 45 ° with respect to the axis of the roll, discontinuous circular hole dies 17 are formed at four locations between the rolls by the four groove forming grooves.

On the outlet side of the first rolling mill 10 having such a configuration, as shown in FIG.
As shown in (b), (c), and (d), the second, third, and fourth rolling mills 20, 30, and 40, which have substantially the same structure as the first rolling mill, and plural rolling mills (not shown) have an appropriate length. Installed in tandem in a spaced manner, which constitutes the rolling mill group 5. Each rolling mill has a reduction rate of 15
% Or less, and the central angles around the pass lines of the four roll peripheral surfaces are set, for example, so that the unconstrained portions of the wire W passing through the free surface that is a circular hole type discontinuous portion do not overlap in each rolling mill. In the illustrated example, the adjacent rolling mills are different by 45 °. The central angle does not have to be 45 °, and may be any angle as long as a predetermined purpose can be achieved.

As shown in FIG. 4, both ends of the hole shape of each roll have a relief portion (in solid line) with a diameter (for example, 2R) larger than an extension line (indicated by broken line) of the radius of curvature R at the central portion in the axial direction. Shown) A, A ...

In the method for producing a thin wire according to the present invention, first, the wire W is heated in the high-frequency heating furnace 3 and is passed through each rolling machine of the rolling mill group 5 at a low speed to roll the wire W. Machine group 5, guide 6a
And the front end is wound up by the winder 6, and subsequently the motor 4 and the winder 6 are operated at high speed. As a result, the wire W is unwound from the rewinding machine 1, heated to a predetermined temperature in the high-frequency heating furnace 3, and then caught in the rolling mill group 5. Here, the low speed means a speed at which the tip of the wire can be manually guided to be caught in the roll, and specifically, about 0.5 m / sec or less is preferable.

Alternatively, as another implementation method, first, one end of the winding wire rod having a diameter smaller than the hole type diameter of the rolling mill at the exit end of the rolling mill group 5 is attached to the winder 6 so as to be able to be wound, and the other end side is attached. Guide 6
a, the rolling mill group 5, the high frequency heating furnace 3 and the inlet side guide 2 are inserted and connected to one end of the wire W which is rewoundly attached to the rewinder 1. That is, if the winder 6 is driven,
The wire W is made to be able to be caught in the rolling mill group 5.

When the preparation is completed, the high frequency heating furnace 3, the motor 4 and the winder 6 are operated. Thereby, the wire W is rewound by the rewinder 1
As it is more loosened, it is guided by the winding wire and the entry side guide 2
After entering, it is heated to a predetermined temperature in the high frequency heating furnace 3 and then caught in the rolling mill group 5.

The rolling speed of each rolling mill is determined according to its surface reduction rate, that is, the amount of passage through the hole die per unit time is constant, and the rolling mill on the output side is better than the rolling mill on the input side. The rolling speed is set to be high, and the winding machine has a winding speed determined according to the rolling speed of the rolling mill at the exit end.

The wire W bit in the rolling mill group 5 is successively reduced in diameter by each rolling mill, and becomes a thin wire SW having a predetermined product size by the rolling mill at the exit end.

First, since the axis of the material to be rolled is located at the center of the hole shape of each rolling mill in the rolling mill group 5, smooth rolling is performed during rolling. For this reason, the method of the present invention does not require a guide and does not cause surface defects caused by contact with the guide. Further, in the past, when the rolled material collapsed when restrained by a substantially square or substantially triangular hole shape, in the present invention, since the rolled material is restricted by the circular hole shape, the roundness of the rolled material Even if it is bad, it will not fall down. Further, by making the positions of the four rolls different around the pass line, it is possible to prevent the wire W from being caught in the hole type discontinuous portion. Further, in addition to this, the reduction of surface area is set to 1% or less and the relief portion is formed in the roll, so that triple biting can be prevented and completely prevented. For this reason,
Rolling is never stopped. Further, since the roll is instructed at both ends, the roll is not bent, and the dimensional accuracy of the product can be improved.

Further, since the rolling mill is configured to drive two of four rolls, it is possible to reduce the storage space of the drive mechanism in the housing as compared with the case of driving all four rolls or three rolls. In addition, it is possible to prevent the structure from becoming complicated and to make the structure compact and highly rigid. Further, it is possible to prevent slipping and warping of the wire rod W that occurs in the case of asymmetric rolling in which one roll is driven.

In this way, the wire W is rolled into the small-diameter wire SW, and the small-diameter wire SW is wound up by the winder 6 via the guide 6a and the rolling is completed.

Although the wire W is heated and hot-rolled in the high-frequency heating furnace in the above embodiment, the present invention is not limited to this and can be applied to the case of cold-rolling without heating the wire. Is.

Table 1 shows the results of an investigation of the rollable range per unit in continuous rolling in the case of using the 4-roll method of the present invention and in the case of using the 3-roll or 2-roll method. In Table 1, “◯” indicates that good rolling was possible, and “x” indicates that biting occurred and rolling could not be continued.

The rolls used were hole-shaped rolls having a substantially circular cross section.

As is clear from Table 1, it is possible to reduce the surface reduction rate to 17% per pass in the 4-roll rolling, but to 10% in the 3-roll rolling and 8% in the 2-roll rolling.

Considering the number of rolling required when rolling a small diameter wire of 5.5φ to 2φ based on this, 11 rolls in the case of 4-roll rolling, 19 rolls in the case of 3-roll rolling, 2 In the case of roll type rolling, at least 24 units are required.

As you can see, in case of 4-roll rolling,
40 compared to the case of rolling with a two-roll system
The number of rolling mills can be reduced by ~ 55%, and the rolling mill group can be shortened to realize a compact rolling mill.

(Numerical example)

Diameter: 5.5 mm, Material: S45C wire rod was heated to 1100 ° C., hot rolling was performed according to the present invention using 11 rolling mills with 10% reduction in area per pass, diameter: 2.02 A thin wire having a diameter of mm was produced, and the same wire was cold-rolled according to the present invention without heating the same wire to produce a similar thin wire. Manufacturing conditions were as follows: roll diameter during rolling: 180 mmφ, material speed on rolling mill group side: 25 m / sec.

Both the manufactured thin wire rods have no surface flaws, and the dimensional accuracy of hot rolled material and cold rolled material is 2.02mmφ ± 0.03,2.0, respectively.
It was as good as 2 mmφ ± 0.015.

Further, the rolling was stopped halfway and the cross-sectional shape of each part of the material to be rolled rolled by each rolling mill was investigated. As a result, each cross-sectional shape kept circular. Therefore, by removing one or two or more rolling mills from the last stage and rolling the rolling mill, the degree of freedom in product dimension can be relatively large.

For reference, the dimensional accuracy of the thin wire rod manufactured by the 3-roll method is 2.02 mm for hot rolled material and cold rolled material.
φ ± 0.045, 2.02 mm φ ± 0.025.

It was also confirmed that the case of using the two-roll system was substantially the same, and it was confirmed that the dimensional accuracy when using the rolling machine of the four-roll system was significantly superior.

〔effect〕

As described in detail above, according to the method of the present invention, a plurality of rolling mills each having four hole rolls having a circular hole formed on the peripheral surface around the pass line are installed in a tandem, and the adjacent rolling mills are each The rolls are arranged so that the unconstrained parts of the wire rod do not overlap, so even if the area reduction rate is increased, the material does not squeeze out. The present invention has excellent effects such as a large reduction in size, overall compactness, markedly improved rolling dimensional accuracy, and high-yield, high-productivity production of small-diameter wire rods. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIGS. 2 and 3 are configuration explanatory views of a rolling mill of an apparatus used in the present invention, and FIG. 4 is an explanation of a roll escape portion of the apparatus used in the present invention. Figure, No. 5, 6, 7,
8, 9 and 10 are explanatory views of the prior art. W: Wire rod, SW: Thin wire rod, 5: Rolling mill group, 6 ...
Winder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chihiro Hayashi 1-3-3 Nishi-Nagasumotodori, Amagasaki City, Hyogo Prefecture Sumitomo Metal Industries, Ltd. Research Institute (56) Reference JP-A-54-133465 (JP , A) JP-A-58-303 (JP, A) JP-B-54-15020 (JP, B1)

Claims (1)

[Claims] 1. A method for producing a small diameter wire rod having a smaller diameter by drawing and rolling a wire rod by a rolling mill group in which a plurality of rolling mills are installed in tandem. A hole type roll is arranged, and the hole type is a substantially circular hole type, and the rolling mills adjacent to each other are arranged so that the unconstrained portions of the roll hole types with respect to the wire do not overlap. The method for producing a thin wire rod is characterized in that every other cross-section reduction rate is 40% or more, drawing rolling is performed, and the thin wire rod is wound on the exit side of the rolling mill group.