JP3006410B2 - Manufacturing apparatus and manufacturing method for fine wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a thin wire having a diameter of 1 to 3 mm.

[0002]

2. Description of the Related Art Conventionally, bar and wire rods have been rolled by passing a material to be rolled through various series of holes using a two-roll type rolling mill. FIG. 10 is a front view of a rolling roll and a material to be rolled in a two-roll rolling method, as viewed from a pass line exit side. The material to be rolled 13 is sandwiched between the rolls 11 and 12 from above and below. As the material is rolled, the material to be rolled 13 expands in the direction of the gap between the rolls 11 and 12, resulting in a widened shape. The width expansion is largely affected by a slight variation in the diameter of the material to be rolled, a variation in tension between rolling mills during continuous rolling, and the like, and a two-roll type rolling mill has sufficient accuracy in product dimensions. There was a problem that can not be.

A four-roll type rolling mill having a smaller width spread than such a two-roll type rolling mill is disclosed in, for example, JP-A-50-140354 (Publication 1) and JP-A-58-303.
(Publicly known technology 2). In a four-roll rolling mill, the rolling component on the material to be rolled acts centripetally and uniformly in a cross section orthogonal to the pass line of the material to be rolled, so that the material to be rolled swells and has a widened shape. To prevent FIG. 11 is a cross-sectional view of a four-roll type rolling mill proposed in the related art 1, as viewed from a pass line exit side for each stand. The four rolls 21, 22, 23, 24 are arranged to form a substantially square, and a plurality of such stands are
The arrangement angle of the rolls with respect to the pass line is rotated by 45 °, and the dimensions of the substantially square hole type are sequentially reduced, and the rolls are installed in tandem. The rectangular material 25 to be rolled is sandwiched between these four rolls and rolled.
A reduction is applied from the 25 corners to reduce its dimensions.

[0004] FIG. 12 is a diagram showing a conventional technique 2 proposed in 4.
It is sectional drawing which looked at the rolling mill of the roll system from the pass line exit side for every stand. The four rolls 31, 32, 33, and 34 are arranged so as to form a substantially square shape in such a manner that both ends of the rolling surface of the pair of rolls 31 and 33 facing each other are overlapped with the side surfaces of the other rolls 32 and 34. A plurality of such stands are installed in tandem with a reduced size of the substantially square hole. The rectangular material 35 having a rectangular cross section, which is the material to be rolled, is sandwiched between these four rolls and rolled to reduce its size. In this case, the arrangement angle of the rolls with respect to the pass lines of the plurality of rolling mills is constant, and the same surface of the rectangular material 35 is constantly reduced.

In the above-mentioned four-roll rolling mill of the prior art 1, the amount of width expansion is small, and the reduction in area given to the material to be rolled is geometrically large. However, since the rolls are arranged at an angle of 45 ° with respect to the pass line at each of the plurality of stands, the rolled material between the stands, that is, the twist, is extremely likely to occur. FIG. 13 is a cross-sectional view in a direction orthogonal to a pass line of the four-roll rolling mill proposed in the related art 1 (see FIG. 11). The manner in which the material to be rolled is rolled by this rolling mill will be described. First, a rectangular material 25 with a cross section indicated by a broken line is inserted into the rolling entrance of the rolling mill. At this time, the corners 25a, 25a, ... of the material to be rolled contact the roll groove bottoms 21a, 22a, .... Then, rolling is applied to the corners 25a, 25a,.
4 is formed in the same shape as the substantially square hole die formed. This makes it possible to obtain a high area reduction rate of 25 to 35% per pass.

However, at the start of rolling, the bottom of the roll groove is
21a, 22a,... Are corners 25a, 25a,..., So that the contact area is small, and as the contact width is increased by rolling, the restraint by the roll of the rectangular material 25 becomes unstable, and the rectangular material 25 , A rectangular section material 25 falls down to the left or right. The larger the ratio of the diagonal dimension D on the entry side section to the opposite side dimension d on the exit side section of the rectangular section material 25, the greater this rotational moment becomes, and the more likely it is to collapse and twist.

As described above, in the four-roll rolling mill of the prior art 1, the material to be rolled is easily twisted, and a guide roller for preventing twisting is required between the stands. When rolling small-diameter materials to be rolled, it is necessary to mount the guide roller immediately before the roll-in side because the degree of twist is large, but since the distance between the four rolls is small, the guide roller is rolled. It becomes difficult to install the material immediately before the entry side, and it is not possible to sufficiently prevent the material to be rolled from being twisted. Further, although a guide roller can be attached to a material having a relatively large diameter, there is a problem that a guide flaw is generated by the guide roller.

On the other hand, in the four-roll type rolling mill of the prior art 2 (see FIG. 12), since the width expansion amount is small and the roll arrangement angle with respect to the pass line is constant at all stands, the material to be rolled is No rolling moment is applied to the roll, and the rolled material is not twisted between the stands. Therefore, there is no need for a guide roller for preventing falling. However, there is a problem that the rolled material slightly bites into the roll gap because the rolling is always applied from the same direction.

In order to solve these problems, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 63-168202 (Prior Art 3)
An approximately circular hole type four-roll type rolling mill has been proposed. FIG. 14 is a front view of a plurality of rolling mills of the 4-roll type proposed in the prior art 3 as viewed from the exit side of the pass line, and FIG. 15 is an enlarged sectional view of one of the rolling mills. .
The four rolls 41, 42, 43, 44 constituting the rolling mill 40 are arranged in a substantially circular hole shape. A plurality of such stands rotate the roll arrangement angle with respect to the pass line by 45 °, and form a substantially circular hole shape. Are installed in a tandem with the dimensions of each being reduced gradually. The circular material 45 having a circular cross section, which is a material to be rolled, is rolled by being sandwiched between these four rolls to reduce its size.

In the present method, the holes of the roller are circular and the stands 40, 40,.
However, it is characterized in that the phases are alternately shifted so that the unconstrained components in the roll hole form do not overlap. When all roll holes are round, the material to be rolled is rolled without biting even if twisted, and the aspect ratio at the time of reduction of the material to be rolled is close to 1, so that the rolling stand Since the torsional moment of the falling is small, a thin wire is manufactured without attaching a falling prevention guide.

According to the above-mentioned method, it is possible to easily roll a thin wire having a diameter of about 5 mm, which was difficult to be rolled, and to prevent the occurrence of surface flaws caused by contact with a guide for preventing falling down. A thin wire can be manufactured with much higher efficiency than the wire drawing method, which is a method for manufacturing a diameter wire.

[0012]

However, when the present inventors tried an additional test for the method and the apparatus of the prior art 3, when the diameter of the material to be rolled was further reduced, it was found that the material in the pass line direction was not It was found that the torsion of the material to be rolled was noticeable between adjacent rolling mills, and the material began to bite into the gaps of the grooved shape, making it impossible to produce a high-quality thin wire.

In order to prevent the twist between the stands, it is conceivable to reduce the distance between the stands as much as possible. However, the diameter of the roll must be reduced accordingly. However, in order to secure the roll shaft diameter that satisfies the rolling torque and the rolling load, there is a limit to reducing the roll diameter, and it is necessary to increase the number of roll rotations in order to secure a normal production speed. There is a limit to the number of rotations of the roll. For these reasons, there has been a problem that reducing the stand-to-stand distance causes a reduction in production capacity.

The present invention has been made in view of the above circumstances, and is an apparatus for rolling a wire having a small diameter of 1 to 3 mm by preventing the material to be rolled from being twisted between stands without reducing the production capacity. And a method.

[0015]

According to a first aspect of the present invention , there is provided an apparatus for manufacturing a small diameter wire rod, wherein a material to be rolled is rolled by a continuous rolling mill group and a roller die apparatus arranged downstream of the continuous rolling mill group. The continuous rolling mill group comprises a plurality of rolling stands including a four-way rolling stand provided with a V-shaped groove on a peripheral surface so as to form an octagonal groove. Are arranged so that the groove bottom positions of the roll dies of adjacent rolling stands tilt at 45 ° around the pass line, and the distance between the dies in the pass line direction of the adjacent rolling stands is set between the rolling stands. The maximum diameter of the material to be rolled through is 100 times or less, and the roller die device is configured such that a plurality of roller dies of a two-roller type having a circular hole shape are formed such that a groove bottom position of a roll hole type of an adjacent roller die is rolled. 90 around the pass line ° arranged so as to be tilted, and the distance between the dies in the pass line direction of the adjacent roller dies is the maximum diameter of the material to be rolled passing between the roller dies.
It is characterized by being 40 times or less.

According to a second aspect of the present invention, there is provided a method of manufacturing a thin wire according to the first aspect of the present invention, wherein a reduction in area at each rolling stand of the continuous rolling mill group is set to 20 % or less, and It is characterized in that the total area reduction rate of the dice device is 6 to 12%.

[0017]

[Function] The applicant of the present application has already filed 8
A rolling mill provided with rolls having a square hole shape has been proposed. In this rolling mill, a V-shaped groove is provided on the peripheral surface of each roll, and the occurrence of twist and biting can be suppressed by stabilizing the contact between the groove bottom and the material to be rolled. In the apparatus for manufacturing a thin wire according to the present invention, a plurality of rolling stands including an octagonal hole-shaped rolling stand and a plurality of roller dies are arranged at a predetermined distance from each other. Also, there is no possibility of twisting or falling during the sizing process with a roller die.

In the method for manufacturing a thin wire according to the present invention, the reduction rate of the rolling stand and the total reduction rate of the roller die apparatus are set to predetermined values or less using the above-described manufacturing apparatus. Is reduced to such an extent that no biting or folding occurs.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a schematic side view showing the configuration of the manufacturing apparatus of the present invention. A turntable type horizontal rewinding machine 10 around which a material to be rolled W is wound is provided at the uppermost stream of the production line in the present apparatus. On the downstream side of the rewinding machine 10, a straightening machine 12 provided with a guide roller 11 on its entry side is disposed, and the material W to be rolled out from the unwinding machine 10 is bent by the straightening machine 12. It is being corrected.
On the downstream side of the straightening machine 12, a continuous rolling mill group 20 having a guide roller 13 on its entry side is provided. Continuous rolling mill group 20
Is a tandem arrangement of a plurality of four-roll rolling stands 21, 22, 23,... Having an octagonal hole as described later, and passes through a free surface which is a discontinuous portion of the octagonal hole. The unconstrained portion of the material W to be rolled is set at each of the rolling stands 21, 22, 23,
Are arranged so as not to overlap with each other, and the rolled material W sent from the straightening machine 12 is continuously rolled.

On the downstream side of the continuous rolling mill group 20, a roller die device 30 for performing circular sizing on the rolled workpiece W is provided.
Are arranged. The roller dice device 30 includes two two-roll roller dice 31 and 32 arranged as described below so that the free surface of the groove, that is, the roll gap does not overlap. SW is obtained. On the downstream side of the roller die 30, a vertical winder 15 for winding the small-diameter wire SW through a swing roller 14 arranged as a traverse mechanism for aligning and winding the small-diameter wire SW is provided. I have. Winding machine 15 is a thin wire rod SW
The roller is rotated at a predetermined speed at which sizing is performed by the roller dice device 30 by applying a required torque while fixing the leading end of the roller.

The continuous rolling mill group 20 includes a plurality of four-roll rolling stands arranged in parallel in the pass line direction. FIG. 2 is a schematic front view of the first rolling stand of the continuous rolling mill group 20. The housing 7 having an octagonal front view is provided with vertical and horizontal cross-shaped holes extending in four directions perpendicular to each other from the center thereof.
2, 3 and 4 are shafts 1a, 2a, 3a and 4a at both ends thereof.
Is rotatably inserted into a bearing hole formed in a longitudinal wall surface of the hole, and is supported in a double-supported manner.

A motor (not shown) is connected to one end of the shaft 1a. When the roller 1 is driven by driving the motor, the internal rollers fitted to the roller 1, 2, 3 and 4 are driven. Rolls 2, 3, 4 by gears 6, 6, ...
Are linked. Driving the four rolls at the same time in this manner is effective in stabilizing the material W to be rolled into the four rolls and preventing slippage with the rolls during rolling.

FIG. 3 is an enlarged sectional view of the first rolling stand shown in FIG. 2 in a direction perpendicular to the pass line, and shows the vicinity of the pass line. The following description will be made by taking one groove type roll as an example. The peripheral surface of the hole type roll 1 has a groove 1b having a V-shaped cross section at the center in the axial direction of the hole type roll. An inclined surface inclined by 45 ° with respect to the roll axis is formed. The groove bottom opening angle θ of the V-shaped groove 1b is
Four rolls are formed at the same angle, and a radius is provided at the bottom of the groove. In addition, a radius is also provided at the apex formed by the groove 1b having a V-shaped cross section and the inclined surface, so that each corner of the material W to be rolled is smoothly rolled. At this time, the radius of the groove bottom is 1/3 to 1/5 of the octagonal diagonal dimension.
It is desirable to set the value to about 1 /. Four such rolls are V-shaped grooves 1b, 2b, 3b, 4b.
And a discontinuous octagonal die 5 is formed at four locations between the die rolls.

In the continuous rolling mill group 20, a plurality of rolling stands having such a configuration are installed in tandem with an appropriate distance therebetween. FIG. 4 is a schematic side view showing first, second, and third rolling stands among a plurality of rolling stands.
FIG. 2 is a schematic front view of these as viewed from the pass line exit side. In the figure, reference numerals 21, 22, and 23 denote first, second and third rolling stands. The unconstrained portions of the material W to be rolled which pass through a free surface which is a discontinuous portion of an octagonal hole are used in each rolling stand. 21,22,23,
In order to avoid overlapping, the central angles around the pass lines of the four perforated rolls are, for example, different by 45 ° between adjacent rolling stands in the illustrated example. The central angle is not limited to 45 ° and may be any angle that can achieve a predetermined purpose. In this embodiment, A and C are horizontal stands, and B is a 45 ° tilt stand. Further, adjacent the distance from the center distance L ₁ i.e. the caliber center of the pass line direction between rolling stands 21 and 22 to the grooved center, 100 of the maximum diameter d ₁ of the rolled material W passing through that point It is set to less than twice. FIG. 6 is a cross-sectional view in the direction orthogonal to the pass line of the material W to be rolled by the rolling stand. Maximum diameter d ₁ = 2R of rolled material W
_Is one.

FIG. 7 is a schematic side view showing the configuration of the roller dice device, and FIG. 8 is an enlarged cross-sectional view of the roller dice in a direction perpendicular to the hole-shaped pass line. In the drawing, reference numerals 31 and 32 denote two-roll cassette roller dies, which are arranged so that the free surfaces of the holes, that is, the roll gaps do not overlap.
The roller dies 31, 32 are of a hole type having relief portions on both sides. The outer diameter of the octagonal thin wire formed by the continuous rolling mill group 20 is subjected to light pressure sizing on the outer diameter thereof by a roller dice device 30 to be finished in a circular shape. The sizing area reduction rate is set so that the minimum area reduction rate necessary to finish the corners of the octagon in a circular shape is sufficient, and the total area reduction rate of the roller die device 30 is 12% or less. You. The adjacent roller die center distance L ₂ of is set below the maximum of 40 times the diameter d ₂ of the rolled material W passing through the point.

Each of the roller dies 31, 32 has a structure capable of opening and closing a gap which is the distance between the axes of the opposing rollers, and the leading end of the wire passes through the roller dies 31, 32 to take up the winding machine. After being wound around 15, it is adjusted to a predetermined gap. Thereafter, the interlocking drive of the continuous rolling mill group 20 and the roller die device 30 is started. The opening and closing of the gap of the roller die device 30 may be based on an eccentric shaft mechanism or may be based on an adjusting mechanism of a set screw supporting the roller shaft. In the case of rolling an extremely expensive wire rod, a pinch roll for pulling out the distal end of the small-diameter wire rod SW is disposed near the exit side of the roller dice device 30 and on the entrance side of the swing roller 14, and the fine pinch roll is provided. The drawing operation until the diameter wire SW is wound around the winder 15 may be performed. Thereby, the yield loss of approximately 1 m of the linear wire rod SW having a diameter of about 1 mm can be eliminated.

Further, the gap of the roller die device 30 may be adjusted according to the deformation resistance of the material to be rolled. Thereby, the product dimensional accuracy can be further improved.

Next, the operation of manufacturing a thin wire using the apparatus having the above configuration will be described. First, after the material W to be rolled out from the coil mounted on the rewinding machine 10 is supplied to the straightening machine 12 via the guide roller 11 and straightened,
It is sent to the entrance of the continuous rolling mill group 20. The workpiece W is sequentially reduced in diameter by the low-speed drive of the continuous rolling mill group 20, and the workpiece W having an octagonal cross-sectional shape is obtained and introduced into the roller die device 30. The tip of the small-diameter wire rod SW circularly sized by the roller dice device 30 is wound around a winder 15 via a swing roller 14. After such a wiring process is performed, the continuous rolling mill group 20 is driven at high speed to perform high-speed rolling.

The distance between adjacent rolling stands in the continuous rolling mill group 20 is set to approximately 100 times or less the wire diameter, the reduction in area per stand is set to approximately 20% or less, and the distance between adjacent roller dies in the roller die unit 30 is set. Approximately 40 times or less the wire diameter, and the total area reduction rate is 6
Since it is set to ~ 12%, twist between stands can be suppressed.

Next, a specific example in which a thin wire is manufactured using the manufacturing apparatus and the manufacturing method of the present invention will be described.

Numerical example 1 Using the above equipment, φ3.0mm
Cold rolled into 100kg x 3 coils of the material W to be rolled
A 1.0 mm thin wire SW was manufactured. Material to be rolled: Low carbon steel (0.1% C) wire, outer diameter 3.0mm Rolling mill group: 24 rolling stands Hole roll diameter 100mm Distance between center of hole shape of adjacent rolling stands L ₁ 110mm Reduction of surface per stand Rate 10% Circular hole type roll: 5 stands on the upstream side Octagonal hole type roll: 19 stands on the downstream side Groove bottom opening angle θ 141 ° Roller dice device: 2 roller dice Hole type roll diameter 30 mm Adjacent roller dice Hole center center distance L ₂ 40mm Total area reduction 8% Outgoing rolling speed 1000m / min

FIG. 8 is a schematic sectional view of the circular hole type rolls of the five stands on the upstream side of the rolling mill group used in the present embodiment, as viewed from the pass line exit side. Escape portions are provided on both sides of the peripheral surface of the roll to prevent biting. FIG. 9 is a schematic cross-sectional view of the roller dice used in the present embodiment as viewed from the exit side of the pass line. Escape portions are provided on both sides of the peripheral surface of the roller die to prevent biting.

As a result, a small-diameter wire rod SW was manufactured with a dimensional accuracy of φ1.0 ± 0.03. In the manufactured small diameter wire rod SW,
No biting flaw due to the occurrence of falling was observed at all, and the surface quality was good. Note that a water-soluble lubricant was used to cool and lubricate the workpiece W and the tool during rolling.

Numerical example 2 Using the same apparatus as in Example 1 described above, the entrance side wire diameter and the exit side wire diameter were variously changed, and the presence or absence of occurrence of falling of the material to be rolled was examined. Table 1 shows the diameter of the material to be rolled, the diameter of the product, and the result of the presence or absence of falling. L ₁ represents a grooved center distance between rolling stands, L ₂ denotes a grooved center distance between roller die. Evaluation I is the presence or absence of twist between the rolling stands, ““ ”indicates no twist, and“ X ”indicates occurrence of twist. Evaluation II is the possibility of sizing between roller dies.
“×” indicates that sizing is impossible. In addition, the conventional example used the continuous rolling mill group comprised only of the circular hole type roll.
In addition, the sizing situation in the roller dice device was omitted for those in which twist occurred during rolling in the continuous rolling mill group.

[0035]

[Table 1]

The results shown in Table 1 indicate the following. First, as shown in Comparative Example Nanba1,7,11, regardless the rolled material diameter, if L ₁ / d ₁ in the continuous rolling mill group exceeds 100, the rolled material is in rolling mill Turned around the axis. Due to this, the material to be rolled is not sent according to the predetermined hole shape,
Biting occurred in the gap between the rolls, and folding occurred at the biting portion on the downstream stand. Comparative Example N
As shown in O.5,8,12, roller if it exceeds L ₂ / d ₂ is 40 in the die apparatus, the remaining corner portions in the cross-sectional shape sizing is insufficient for the wire which is formed into an octagonal, Cross-sectional dimensional accuracy is low. This is because the wire is twisted between the roller dies arranged adjacent to each other, and sizing from two orthogonal directions is not performed.

On the other hand, in Examples Nos. 2, 3, 4, 6,
As shown in 9, 10, 13, and 14, L ₁ / d ₁ ≦ 100 and L
_{When the} value was set in the range of ₂ / d ₂ ≦ 40, biting, folding, and defective shape could be completely prevented.

Further, as shown in Conventional Examples Nos. 15 and 16, when octagonal holes were not used in the continuous rolling mill group but circular holes were used in all the stands, L ₁ / d ₁
Even when set to ≦ 100, twisting between rolling mills occurred. In order to prevent this torsion, it is necessary to shorten the distance between the stands, which leads to a reduction in the roll diameter, resulting in a shortened roll life and a reduced rolling speed. N like this
O.15, to 16, Example No. 9, 10 is L ₁ / d ₁ = 100
Indicates that good rolling is possible. Thus, compared to the conventional rolling method using a circular hole type roll, in this embodiment, it is possible to use a large roll diameter,
A high roll peripheral speed can be easily obtained, and the roll life and the life of other parts can be increased about twice.

In the examples, the winding speed at the line exit side was 600 to 1000 m / min, and a thin wire could be produced without any problem. This is comparable to high speed machining which is equivalent or several times higher than the drawing speed in the conventional drawing method.

Numerical example 3 Using the same apparatus as in Numerical Example 1, four types of stainless steel (SUS304) wire, pure titanium (JIS type 2) wire, titanium alloy (Ti-10Zr) wire, and high carbon steel (0.80% C) wire were used. The material to be rolled was rolled. Rolled material of φ3.0 mm was rolled to φ1.0 mm in all materials. As a result, there was no occurrence of twist between the rolling mills and between the roller dies, and it was possible to manufacture thin wires with an accuracy of ± 0.03 mm, respectively.

In the conventional manufacturing method using a hole-shaped die, an off-line lubricating base treatment is performed in order to prevent seizure of a hard-to-stretch wire such as a stainless steel wire, a pure titanium wire, or a titanium alloy wire. . However, in the present embodiment, the friction between the tool and the wire is not sliding friction but rolling friction in both the upstream continuous rolling mill group and the downstream roller die apparatus. It is only necessary to supply them, and it is not necessary to perform a lubrication base treatment specific to each material. As described above, in this example, various metal wires, including inextensible wires, could be easily rolled into small-diameter wires.

Numerical example 4 In the case where the distance between the devices is set short to prevent twisting between the devices, the roll diameter of the rolling mill and the roller diameter of the roller die must be reduced. Therefore, using stainless steel (SUS304) wire as a material to be rolled, desirable lower limit values of the distance between the stands of the rolling mill and the distance between the roller dies were examined. The reduction rate of the rolling stand is set to 10% per stand, and φ5 mm stainless steel is
It was rolled into a 1.8 mm thin wire. The results are shown in Table 2 for the continuous rolling mill group and in Table 3 for the roller dice device.

[0043]

[Table 2]

As shown in Table 2, when L ₁ / d ₁ in the rolling stand is 30 or more, the bearing is not damaged and the tool surface is light for 10 to 20 tons of the rolled material. It can be used with care. However, when L ₁ / d ₁ is less than 30, it can be seen that damage occurs in a short period of time because a small-sized bearing is used.

[0045]

[Table 3]

Further, as shown in Table 3, when L ₂ / d ₂ in the roller die is 20 or more, no damage to the bearing is observed for the production of 10 tons, and L ₂ / d ₂ is less than 20. In this case, it can be seen that seizing of the bearing occurs.
Thus, L ₁ / d ₁ in the rolling stand is about 30 times or more, and L ₂ / d ₂ in the roller die is about 20 times.
It is desirable to set it to twice or more.

Numerical Example 5.4 The optimum shape of the V-shaped groove and the area reduction ratio of the four-sided roll mill and the range showing the effect were examined. Table 4 shows the results. "○" in the evaluation column is good, "x"
Indicates a failure, and “△” indicates a failure depending on the material.

[0048]

[Table 4]

As shown in Table 4, when the area reduction rate per stand is set to 20% or less, it is understood that no twisting or biting occurs. If the reduction rate is 8%,
When rolling a methane titanium alloy, twisting or entanglement occurred. Regarding the lower limit of the area reduction rate, there is no problem in performing rolling even if it is small, but for example, in the case of a reduction area of less than 8%, the number of stands for performing required processing becomes enormous. Not economic. Table 5 below shows the area reduction rate per stand and the number of stands.

[0050]

[Table 5]

As shown in Table 5, when the area reduction rate per stand is smaller than 8%, the number of stands increases. Thus, it is found that the area reduction rate per stand is practically 8% or more.

On the other hand, as shown in Table 4, the roll bottom opening angle θ was 13% in continuous rolling at a 10% reduction in area.
Slight biting occurred at 5 °. On the other hand, twist occurred when θ was 155 °. From this, the groove bottom opening angle θ is 137 ° ~
It can be said that setting to 150 ° is desirable.

When the groove bottom opening angle θ is 135 °, the groove shape is a regular octagon, so that the roll groove bottom and the hole diameter on both sides are equal (see FIG. 6), and the stand Even if the area reduction rate is set to 8%, the eclipse may occur depending on the material to be rolled. In order to prevent biting by making the hole radius on both sides of the roll slightly larger than the V-shaped groove bottom hole radius R ₁ , the groove bottom opening angle θ must be 1
It is desirable to set it larger than 35 °.

Numerical example 6 The optimum value of the area reduction rate in roller dies, the effect range and the number of units were investigated. Table 6 shows the results. “○” in the evaluation column indicates good, and “×” indicates bad. When the area reduction rate in the roller die apparatus is set to 6% or more, the sizing in the entire circumferential direction of the cross section is reliably performed, and the outer diameter accuracy within ± 0.03 mm is obtained. However, if it is less than 4%, the amount of reduction is insufficient, and sizing in a circular shape cannot be performed. On the other hand, the total area reduction rate is 15%
In the case of (1), the rolling amount was too large, so that the biting by the roller die occurred. From Table 5, it can be seen that when the total area reduction rate is set to 6 to 12%, it is possible to completely prevent biting from the hole mold.

[0055]

[Table 6]

The number of roller dies is 2
Since the wire rod having an octagonal cross section can be sized in a circular shape by the reduction from the direction, at least two roller dies are required. When three roller dies are provided, the dimensional accuracy of the cross section can be improved. As shown in Table 6, by making two Lala dice into three,
It can be seen that the eccentricity difference of the cross-sectional shape has been improved from ± 0.030 to ± 0.015.

In the above embodiment, the distance between the most downstream stand of the continuous rolling mill group and the most upstream roller die of the roller die apparatus is not particularly defined. This is because the continuous rolling mill group and the roller dice device have significantly different device configurations, for example, it is difficult to shorten this distance because the rolling unit is housed in the housing case,
Twisting before sizing is not a problem, and twisting during sizing affects the product. Rather, considering the workability at the time of wiring at the end of the wire, the gap between these devices is 0.
It is better to be separated by about 3 to 1 m.

In this embodiment, circular holes are used for the five stands on the entrance side of the continuous rolling mill, and eight stands are provided for the 19 stands after the intermediate stand, which is continuously reduced in diameter by remarkable reduction.
Although a square hole type is used, the present invention is not limited to this.
It suffices that two or more square hole type rolling stands are provided.

In this embodiment, the roller die device 30 is used.
Is provided with two cassette roller dies, but is not limited to this. When sizing a non-rolled material having an octagonal cross-section in a circular shape, it is necessary to perform sizing from a minimum of two directions using a roller die with a two-roll circular hole, so if at least two roller dies are provided, good.

[0060]

As described above, in the present invention, rolling is performed using a four-sided roll rolling stand having an octagonal hole shape.
The present invention has excellent effects, such as producing a thin wire of 1 to 3 mm by sizing using a two-roll type roller die to prevent twisting and falling of the material to be rolled between stands and the like. It is.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a configuration of a manufacturing apparatus of the present invention.

FIG. 2 is a schematic front view of a first rolling stand of the continuous rolling mill group of the present invention.

FIG. 3 is an enlarged cross-sectional view of a first rolling stand shown in FIG. 2 in a direction orthogonal to a pass line.

FIG. 4 is a schematic side view showing first, second, and third rolling stands.

FIG. 5 is a schematic front view of the rolling stand of FIG. 4 as viewed from a pass line exit side.

FIG. 6 is a cross-sectional view in a direction orthogonal to a pass line of a material to be rolled by a rolling stand.

FIG. 7 is a schematic side view showing the configuration of the roller dice device of the present invention.

FIG. 8 is an enlarged cross-sectional view in a direction perpendicular to a hole-shaped pass line of a roller die.

FIG. 9 is a schematic cross-sectional view of the roller die of the present embodiment as viewed from a pass line exit side.

FIG. 10 is a front view of a rolling roll and a material to be rolled in a conventional two-roll rolling method.

FIG. 11 is a cross-sectional view of a conventional four-roll type rolling mill viewed from a pass line exit side for each stand.

FIG. 12 is a cross-sectional view of a conventional four-roll rolling mill viewed from a pass line exit side for each stand.

FIG. 13 is a cross-sectional view of a conventional four-roll rolling mill in a direction perpendicular to the pass line.

FIG. 14 is a front view of a plurality of conventional four-roll rolling mills as viewed from a pass line exit side.

FIG. 15 is an enlarged sectional view of a die of the one rolling mill in FIG. 14;

[Explanation of symbols]

 1-4 hole type roll 1b-4b groove 5 octagonal hole type 7 housing 20 continuous rolling mill group 21-23 rolling stand 30 roller die unit 31, 32 roller die W rolled material SW small diameter wire

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 13/10 B21B 13/12 B21B 1/16

Claims (2)

(57) [Claims] 1. A rolled material is rolled by a continuous rolling mill group,
An apparatus for producing a small-diameter wire rod by sizing with a roller die device arranged downstream of the continuous rolling mill group, wherein the continuous rolling mill group has a V-shaped groove on a peripheral surface so as to form an octagonal hole shape. A plurality of rolling stands including a four-way roll rolling stand provided with a roll-shaped groove base of an adjacent rolling stand so that the groove bottom position of the roll hole is inclined by 45 ° around the pass line; The distance between the dies in the pass line direction is set to 100 times or less the maximum diameter of the material to be rolled passing between the rolling stands, and the roller die device includes a plurality of two-roller dies having a circular dies. , adjacent the roller groove bottom position of the roll caliber of the die is arranged to be 90 ° tilt around the pass line and said adjacent roller die caliber distance the roller die in the pass line direction 40 of maximum diameter of the rolled material through the
An apparatus for manufacturing a thin wire, wherein the diameter is reduced to twice or less. 2. The production apparatus according to claim 1, wherein the reduction ratio of each rolling stand of said continuous rolling mill group is not more than 20 %, and the total reduction ratio of said roller dice device is 6 to 12%.
%.