JPH1099902A - Method for rolling fine wire rod and apparatus for rolling fine wire rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable execution of a rolling in high reduction of area at the front step and a rolling in high dimensional precision at the rear step by arranging roll stands having small number of the rolls constituting the rolling calivers at the front step and roll stands having large number of the rolls constituting the rolling calivers in the necessary number of the roll stands, respectively. SOLUTION: As the rear step rolling apparatus, in the case of using a four-way rolling system, it is desirable because the good dimensional precision, such as the roundness, is obtd. and as the front step rolling apparatus, in the case of using a two-way rolling system, such profitability is increased that the structure of the rolling apparatus is simpler and the overturn and the overfilling can, be prevented in comparatively easy and 14% - about 20% of the reduction ratio of area per one step of the roll stand can be obtd., etc. Further, in the case of using the two-way rolling system, the change of the roll set is drastically facilitated because a roll shaft can be formed as a cantilever type. Furthermore, in the case of using the two-way rolling system to the front step rolling apparatus, and a chamfered diamond-type cross section to the cross sectional shape of roll caliber, particularly, large effect to prevention of the overturn is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a method for producing a wire rod having a diameter of about 5 mm or less (hereinafter, referred to as a fine wire) by rolling, and an apparatus therefor.

[0002] A method for producing a thin wire is to sequentially roll a billet formed by hot block rolling by a hot rough rolling device, an intermediate and finish rolling device, and to obtain a coil having a circular cross section with a wire diameter of about 5.5 to 7 mm. It is obtained by obtaining a wire, using this as a starting material, and performing further diameter reduction processing while rewinding. A specific method of reducing the diameter is drawing by a hole die or a roll die formed of two or more non-driven rolls in a roll die, or a two-way roll stand including a roll die in two drive rolls. Alternatively, rolling is performed by a rolling device or the like in which one or a required number of stages of a multi-way roll stand in which a roll die is formed of three or more rolls are connected in tandem.

[0003] Among them, the above-mentioned drawing method requires that the leading end of the workpiece be passed through a hole die or a roll die and that the leading end be locked to a drawing drum via a chuck. Is dependent on hand, and the drawing method has a small area reduction rate per pass. Therefore, in order to obtain a thin wire having a desired diameter, many drawing operations and many man-hours are required. It increases as the wire diameter decreases. On the other hand, if the rolling method described above successfully guides the leading end of the material to be rolled from the roll stand exit of the preceding stage to the entrance of the next roll stand and bites it, by connecting a multi-stage roll stand in tandem, For the drawing method,
Since a large reduction in area per pass is obtained, the number of man-hours can be significantly reduced.

If the above-mentioned drawing method or rolling method is performed at a high temperature such as hot or warm, various advantages such as high deformability, low deformation stress, elimination of intermediate annealing, and suppression of microvoids due to cracking of carbide can be obtained. You can take a bath. Further, in the drawing method, only one drawing can be performed with one heating of the workpiece, but in the tandem rolling method, high temperature processing can be realized with several to tens of roll stands by one heating. In addition, the number of heatings and the amount of heating heat for obtaining a wire having a desired diameter can be significantly reduced as compared with the drawing method.

[0005] However, the rolling method using a stand in which a pair of two-way rolls form a roll hole form has the advantage that it is possible to reduce the bite and increase the area reduction rate per tandem step. However, it is generally difficult to obtain a rolled material with high dimensional accuracy such as roundness, especially for small-diameter wires. The above-described multi-roll stand (particularly, four-roll stand) method is suitable.

The method of connecting these various roll stands in tandem is such that the roll hole shape of each roll stand is substantially circular, and the rolling direction of the next roll stand with respect to the preceding roll stand is θ = 180 around the pass line.
° / N (N; number of rolls constituting the roll hole type of the multi-directional roll stand..., When N = 4, θ = 45 °)
The roll stands are arranged in such a manner that they are only swung, and the adjacent roll stands are in such a relationship that the unconstrained portions of the material to be rolled do not overlap each other. In the present invention, this is called a multidirectional tandem mill. The multidirectional tandem mill is configured such that a roll hole area Ai and a roll peripheral speed Vi of an arbitrary i-th roll stand are expressed by A
i × Vi is almost constant (it becomes slightly larger in the later stage)
Is known that is driven by a common drive source.

[0007] In the rolling of a thin wire in a multi-directional tandem mill system, the roll stands of an arbitrary number of stages or more can be collectively removed, so that the diameter of the hole shape of the remaining last roll stand and, accordingly, various types of roll stands. In many cases, wires with a diameter can be obtained. In this tandem rolling,
Since the guides between the roll stands can be eliminated or greatly simplified, the material to be rolled reduces the risk of occurrence of scratches, and the heating time is generally short even in the case of hot or warm rolling. Accordingly, oxidation and decarburization can be minimized, and a wire having a high surface property can be obtained.

In the rolling of a thin wire by a multidirectional tandem mill, the material to be rolled has a small diameter and the roll hole shape is almost circular, so that the material falls down (the cross section of the material to be rolled rotates, (A state where the sheet is rolled down from a direction different from the rolling down direction). JP-A-63-168202 and JP-A-5-200403 disclose, as a means for preventing this fall, a method in which a leading end of a material to be rolled is brought to a winding machine while passing between rolling stands at a low speed. A rolling method has been proposed in which the tip is set on a drum of a winder and then gradually increased to a steady rolling speed.

Japanese Unexamined Patent Publications Nos. 6-182404 and 8-1207 disclose a four-side tandem mill in which the roll hole shape is a regular octagon or a modified octagon shown in FIG. 4 (diagonal distance ratio d ₂ / d> 1). ) To prevent falling. And, JP-A-8-1207 discloses that
It states that a maximum area reduction rate of 20% can be obtained per roll stand. Incidentally, the above-mentioned JP-A-63-16820
According to the proposal by No. 2, since the wire is set to the winding machine and the winding machine at a low speed, even if the wire is heated and wired, the tip of the wire is cooled. Further, the whole material to be rolled following the tip is also limited to low machining conditions such as a reduction in surface area that can be worked at the cooled tip, so that the benefits of high-temperature machining cannot be sufficiently enjoyed.

[0010] As described above, the rolling method using a multi-directional tandem mill requires a small number of man-hours and a variety of diameters having high dimensional accuracy and surface properties when the diameter of the material to be obtained is sufficiently small. In the case of high-temperature processing, there are a number of advantages such as a low calorific value, but if the area reduction rate is small, it is rather disadvantageous. In other words, multi-sided tandem mills generally require large-scale equipment, and the number of rolls constituting the roll hole type is large, and as the number of rolls increases, the structure of the roll stand becomes more complicated and the equipment cost increases, and the reduction in area obtained is reduced. Low (usually 10% for 4-section roll with circular cross section)
Degree). For this reason, the number of tandem stages for obtaining a predetermined area reduction rate increases, so that the economic efficiency decreases. In the case of a small diameter, a multidirectional tandem mill is liable to fall. Accordingly, the present invention provides a wire rod having a small area reduction rate from a material, which is obtained by another method such as a conventional method, so that a wire rod having a large area reduction rate is more stable than a conventional multidirectional tandem mill. An object of the present invention is to provide a method and apparatus for rolling a wire rod having high economy and capable of sufficiently exhibiting the characteristics of a multi-directional tandem mill.

[0011]

According to the present invention, in a processing range from a material wire diameter to a target wire diameter, a thick wire diameter range uses a roll stand having a small number of rolls constituting a roll hole die. The range of the small diameter up to the target wire diameter following the diameter range is
The present invention provides a method and an apparatus for rolling a thin wire having both advantages of a rolling method having a small number of rolls and a rolling method having a large number of rolls constituting a roll groove by rolling with a multi-roll rolling mill.

That is, the method invention of the present application provides a method of rolling a material to be rolled by a rolling device in which a roll forming a roll die is a single roll of three or four roll stands or a plurality of roll stands arranged in tandem. In the method of rolling a thin wire rod to be rolled, the material to be rolled is rolled by a pre-rolling device including a plurality of roll rolls constituting a roll die and arranged in tandem on a roll stand smaller than the number of rolls of the rolling device. And a method of rolling a thin wire rod, wherein the rolling is continuously performed by the above-described rolling device (second-stage rolling device). Is composed of a single roll of three or four roll stands or a plurality of roll stands arranged in tandem, and a roll die provided in front of the latter roll mill. That the number of rolls is a rolling apparatus for fine wire material, characterized in that it consists of preceding rolling mill comprising a plurality groups arranged in tandem of the smaller roll stand than roll speed of the subsequent rolling mill.

In the present invention, when the roll stands of the first and second stages are tandem roll stands, the rolling direction between the respective stages is in the directional relationship as described above by turning θ = 180 ° / N. For example, it is assumed that two adjacent roll stands do not overlap the non-constrained portions of the material to be rolled. In the manufacturing method invention of the present application, the material to be rolled is set on an unwinding machine, and is rolled while being unwound from one end thereof, so that the rolling is independent of the production of the material to be rolled and inspection care. This is advantageous because the start, stop, speed change, and the like of the rolling can be freely performed. As an apparatus for rolling a thin wire according to the present invention, the unwinder sets a reel in which a material coil is wound in a horizontal axis type, rather than setting a material coil in a normal vertical or horizontal axis supply stand. Is desirable from the viewpoint of prevention of tangles.

Further, in both of the inventions of the present application, it is desirable that the dimensional accuracy such as roundness and the like be good if the latter-stage rolling device is a four-way rolling system, and the number of rolls is small if the former-stage rolling device is a two-way system. The structure of the rolling device is simpler, falling and biting can be prevented relatively easily, and the reduction in area per roll stand is 14% or more.
%, For example. Assuming a two-way roll,
Further, since the roll shaft can be of a cantilever type, it is significantly easier to change the roll.

Further, when the pre-rolling device is a two-way system and the cross-sectional shape of the roll hole is a chamfered diamond-shaped cross-section as described later, the effect of preventing falling is particularly large, which is more advantageous than the conventional two-way roll rolling. . Immediately before the first roll stand of the subsequent rolling mill, it is desirable to provide a guide device using a rotary drive roll from the standpoint of preventing falling. Furthermore, the pre-rolling of the present invention makes high-temperature rolling advantageous. That is, when rolling the thin wire at high temperature, conventionally, due to the cooling action of the rolls, the effect could not be sufficiently achieved, but when the number of rolls of the pre-rolling is reduced according to the present invention, the cooling of the material to be rolled is reduced. In addition, it is possible to increase the calorific value of processing per step (depending on the large area reduction rate), which is advantageous in that the wire is kept at a high temperature. It was found that rolling was possible, and the effect of high-temperature rolling could be more enjoyed.

Particularly, high alloys such as tool steel have low deformability,
It is difficult to process due to high deformation resistance and work hardening ability, etc.
In addition, since the performance of the material tends to deteriorate due to the occurrence of the microvoids and a reduction in the heat treatment hardness, etc., facilitating the processing by the high-temperature processing, omitting or reducing the number of intermediate annealings, and reducing the occurrence of the microvoids It is strongly desired to prevent it. Incidentally, the above-mentioned JP-A-8-120
No. 7 shows that a reduction in area per roll stand of 20% can be achieved, but it is 5% per rolling roll, which means 10% reduction in roll cost for a two-way roll. It is considered to be equivalent.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing an embodiment in which the present invention is carried out as warm rolling. FIG. 1 is a schematic configuration diagram showing an example of a device in which a thin wire device according to the present invention is embodied for warm rolling, FIG. 2 is a configuration diagram of a horizontal axis rolling stand in the pre-rolling device,
FIG. 3 is a diagram showing a process of changing the cross-sectional shape of the material to be rolled. In FIG. 1, a rolling device is an unwinding machine 1, a drive roller leveler 2 with an overrunning clutch, a lubricant applying device 3, a high-frequency heating coil 4, a pre-rolling device 5 which is a two-way tandem mill, a guide roll 6 from the upstream side. The rolling mill 7 is a four-sided tandem mill, a rolling device 7, a cooling device 8, and a winding and winding machine 9 during running.

Material coil 1 pulled out from unwinder 1
0 is subjected to a series of processing in each of the above devices as described below. The roller leveler 2 acts to correct the bending of the coil 10, but is not particularly necessary when the bending is uniform. In this embodiment, a feed motion of a predetermined speed is given to the coil 10 until the tip of the coil 10 is bitten by the first roll stand of the pre-rolling machine 5,
After the temperature of the tip of the coil 10 is suppressed from fluctuating, the coil 10 rotates following the feed motion of the coil 10 by the action of the overrunning clutch.

Next, the coil 10 is applied with a paste-form lubricant by a lubricant application device 3 by a nozzle method or the like disclosed in Japanese Patent No. 1000125 to a predetermined uniform thickness, and then passes through the high-frequency heating coil 4. Then, it is heated to a predetermined temperature during the passage. The lubricant film formed by baking in this manner is strong enough to withstand warm or hot drawing, and in the present embodiment, by applying this lubricant film, the wear of the roll and the wear of the roll are reduced. The generation of abrasions with guides and the like is suppressed, and the change in rolling conditions such as the rate of width expansion (the rise of portions that are not constrained by the roll hole shape) due to changes in the material of the material and the surface state of the material is reduced. The versatility of the entire device is expanding. Next, the blank 10 is a pre-rolling mill 5 which is a two-way tandem mill arranged in an appropriate number of tandem stages such that the rolling direction alternates between vertical and horizontal directions.
Rolled in.

FIG. 2 shows an example of the configuration of the horizontal roll stage of the pre-rolling apparatus 5. The pair of rolls 5A are each supported in a cantilever manner by a roll shaft supported by a roll housing 5B containing a pair of pinion gears. In the present embodiment, since the two-way roll stand is used, the roll shaft is of a cantilever type. Therefore, the roll can be easily replaced by attaching and detaching the roll nut 5C. 5D and 5E are a coupling and a speed reducer, respectively. The configuration of the vertical roll stage is almost the same.

Next, FIG. 3 is a view showing a process of changing the cross-sectional shape of the material 10 to be rolled. The solid line shows the cross section of the roll and the material to be rolled, and the broken line shows the cross-sectional shape of the material to be rolled at the roll entrance.
FIGS. 3A and 3B show changes in the cross-sectional shape in the pre-rolling. In this embodiment, the cross-sectional shape of the material to be rolled is a chamfered diamond shape. As is clear from A and B, the material to be rolled at the roll entrance is pressed down while holding the pair of chamfered portions having the higher length of the chamfered diamond-shaped cross section at the bottom of the roll groove. hard. However, the cross-sectional shape of the material to be rolled in the pre-rolling may be a known oval-oval or oval.
A diamond, an oval, a circle, a diamond, a diamond, or the like, which is advantageously shaped for subsequent handling by a subsequent rolling device 7 or a guide roll 6, etc. In the embodiment, the final stage has a deviation from a circular cross section. It has a small chamfered square shape.

Next, the material to be rolled is bitten by a roll stand at the head of the subsequent rolling device 7. In the present embodiment, the guide device 6 is provided in view of the fact that the hole shape of the first roll stand of the post-rolling is circular as shown in FIG. The guide device 6 is a small-diameter rotary drive four-way roll.

That is, the guide device 6 has a small diameter so as to be as close as possible to the first roll of the subsequent rolling in order to enhance the restraining guide action. This causes roll abrasion and scratches on the material to be rolled, and further increases the guiding effect by contacting the four surfaces with no grooves and a four-roll type. In order to reliably guide the leading end of the rolled material to the subsequent rolling device 7, a rotary drive roll type was used. FIG. 3C shows the groove shape of the guide roll 6 and the cross-sectional shape of the material to be rolled. The non-groove, rotary drive, and the cooperation with the above-described lubricant application ensure that the leading end of the material to be rolled is guided, that the material is prevented from falling down over its entire length, and that the material to be rolled has flaws. Prevention of occurrence has become more certain. However, the guide roll is not particularly necessary when the change in the groove shape between the roll stands before and after the guide roll is moderated.

Next, the rear-stage rolling mill 7 is capable of removing an arbitrary number of rear roll stands so that a wire rod having a desired wire diameter range can be obtained by selecting the number of used tandem roll stands. . In the case of high-temperature rolling, the latter-stage rolling device 7 is preferably configured such that the final-stage or further-previous-stage roll prevents a change in the cross-sectional shape and dimensions of the material to be rolled due to its thermal expansion. Preheating by hot air of rolls, infrared lamps, etc., and cooling, for example, by pouring the liquid coolant onto the rolls while preventing it from coming into direct contact with the material to be rolled by a shield plate, air jet or vacuum suction The method of using cooling alone or in combination is effective.

The rolled material that has been subjected to the second-stage rolling is cooled by a cooling device 8 and then wound up by a running distance grasping winder 9. The purpose of cooling is to facilitate subsequent handling and to prevent breakage of the take-up reel. The cooling method is preferably a method of direct contact with cooling water. However, in this case, it is necessary for rust prevention to reliably remove the cooling water. Further, it is preferable that the running gripping winder grips the leading end of the material to be rolled flying in the longitudinal direction between the reel body rotating at a high speed while being separated from each other in the axial direction and its lid.

The embodiment has the following features.
Difference in heating temperature and cooling condition, high speed tool steel, high C, high C
r Difference in deformation behavior due to differences in stainless steel and other steel types, large scale difference in surface condition of rolled material due to removal of surface defects due to unscaled pickling after hot rolling, shaving, etc., diameter of material In order to be able to respond flexibly to differences, etc.
In order to be able to cope with variations in the cross-sectional area of the roll-hole type due to wear or the like, each roll stand of the first-stage rolling device 5, the drive guide roll 6, each roll stand of the second-stage rolling device 7, and the driving of the running and winding winder 9 Independent of each other, having an appropriate negative rotation speed-output torque characteristic, and being capable of setting the rotation speed, and being controlled by individual motors controlled so as to be able to increase and decrease proportionally as a whole. There are features such as combining a high-frequency heating device so as to enable warm or hot rolling, and enabling lubricating film processing. Further, in the present embodiment, the rolled material is formed into a chamfered diamond shape in the first-stage rolling machine, and a drive guide is provided immediately before the second-stage rolling mill, thereby preventing the material to be rolled from falling down.

[0027]

EXAMPLE A material of SKH51, SKH59, SUS440C and steel types A and B, which had been pickled through hot rolling with a diameter of 5.8 mm and then subjected to complete annealing, shot blasting, and descaling, and the surface of the material was subjected to pickling. Material (diameter 5.
3 mm) was subjected to warm rolling by the apparatus of the above embodiment. The working conditions at this time are the finished diameter:
2.0mm, heating temperature: 800 ° C, rolling speed 500m /
min (winding speed). As a result, the surface of each of the obtained materials was beautiful with a lubricating film remaining, and no falling occurred. Next, the obtained wire is continuously annealed, and after cold skin pass drawing, as a result of eddy current inspection, defects due to the above-mentioned rolling are not seen and good, and even about the internal structure, microvoids and the like are not observed, No quality abnormality was found.

Table 2 shows the above working conditions and results. By the way, in Table 1, No. At 1, the total number of roll stages is n = 11 +
2 = 13 stages, total number of rolling rolls, N = 11 × 2 + 2 × 4
= 30 rolls, but if this is to be carried out with a 4-way roll stand at a reduction rate of 10% per roll stand, the total number of rolls n is about 20 and the total number of rolls is 8
Zero is required. That is, according to the present invention, it can be seen that the total number of rolling stages can be reduced by 35% and the total number of rolling rolls can be reduced by 62.5%. The steel types A and B are martensitic stainless steels whose chemical components are shown in Table 2.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

As described above, according to the present invention, a roll stand having a small number of rolls constituting a roll hole die is provided in the front stage, and a roll hole type roll having a large number of rolls is provided in the subsequent stage (however, three or four rolls). Since the roll stands are arranged in the required number of stages, it is possible to perform high area reduction rolling at the front stage without biting or falling down, and high dimensional precision rolling at the rear stage. Products with the same dimensional accuracy and the like can be produced with the number of total rolling roll stands and, of course, the number of total rolling rolls significantly reduced. Further, since the present invention has a small number of total roll stands and a small number of rolls, the cooling of the wire rod, which is a problem in the high-temperature rolling of fine wires, is suppressed, and the high-temperature rolling is facilitated.

[Brief description of the drawings]

FIG. 1 is an overall view of an example of a rolling mill for explaining an embodiment of the present invention.

FIG. 2 is a view showing a configuration of a horizontal axis rolling stand in the pre-rolling apparatus of FIG.

FIG. 3 is a view showing a process of changing the cross section of the material to be rolled in FIG. 1;

FIG. 4 is a view showing a cross-sectional shape of a material to be rolled according to the prior art.

[Explanation of symbols]

1 Unwinder, 2 drive (with overrunning clutch) roller leveler, 3 Lubricant application device, 4 High frequency heating coil, 5 Pre-rolling device (2-roll type), 5A
Pre-rolling roll, 5B Pre-rolling roll housing, 5
C Roll nut, 5D coupling, 5E reduction gear, 6 guide roll, 7 multi-directional tandem post-rolling device, 7a rear (first-stage) roll, 8 cooling device, 9
Rolling machine during running, 10 Coil wire, 10a Pre-rolling shape, 10b Finish rolling shape (true circular shape), 15 Rolling motor

[Procedure amendment]

[Submission date] November 14, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

Particularly, high alloys such as tool steel have low deformability,
It is difficult to process due to high deformation resistance and work hardening ability, etc.
In addition, since the performance of the material tends to deteriorate due to the occurrence of the microvoids and a reduction in the heat treatment hardness, etc., facilitating the processing by the high-temperature processing, omitting or reducing the number of intermediate annealings, and reducing the occurrence of the microvoids It is strongly desired to prevent it.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

[0029]

[Table 1]

Claims (6)

[Claims] 1. A method of rolling a thin wire rod in which a material to be rolled is rolled by a rolling device including a single roll of three or four roll stands or a plurality of roll stands arranged in tandem. In the above, the material to be rolled is continuously rolled while being rolled by a pre-rolling device comprising a plurality of roll stands arranged in tandem on a roll stand in which the number of rolls constituting a roll die is smaller than the number of rolls of the rolling device. A method for rolling a fine wire, wherein the rolling is performed by a device (second-stage rolling device). 2. The method according to claim 1, wherein the material to be rolled is stored in an unwinding machine and rolled while being unwound from one end thereof. 3. The method for rolling a thin wire according to claim 1, wherein at least one of the roll stands constituting the pre-stage rolling device is a two-way roll stand. 4. The method of rolling a thin wire according to claim 1, wherein the rolling by the pre-rolling apparatus is performed while the material to be rolled is heated and heated by a heating means. 5. A post-rolling machine in which the roll to be rolled is formed of a single roll of three or four roll stands or a plurality of roll stands arranged in tandem, and a front part of the rear-rolling mill. Rolling of a thin wire rod, comprising a plurality of pre-rolling machines arranged in tandem on a roll stand having a smaller number of rolls forming the roll hole die than the number of rolls of the post-rolling machine, apparatus. 6. The thin-wire rolling device according to claim 5, further comprising a guide device between the first-stage rolling device and the second-stage rolling device, wherein the guiding device is constituted by a rotary drive roll having at least a pair of rolls facing each other. .