JPH10194594A - Tension control device of wire rolling equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the wire into a ring shape of uniformly excellent quality by providing an electromagnetic device to generate the prescribed tension in the wire by supplying the magnetic force between a wire finish rolling machine and a laying head. SOLUTION: The current value of a pinch roll in the tension control to be executed until the tail end of the wire 4 comes off in a finish rolling machine 1, and the tension operation value at the timing when the tail end of the wire 4 comes off from the finish rolling machine 1 are stored, and the excitation current value is determined based on the stored value. Because the tension value generated in the wire 4 after the tail end of the wire 4 comes off in the finish rolling machine 1 becomes the magnitude of the magnetic force to be applied to the wire 4, i.e., the function of the excitation current value, the excitation current value is determined from the function relationship so that the tension value generated in the wire 4 agrees with the stored operated tension value, and the excitation current value is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tension control device for a wire rod rolling plant.

[0002]

2. Description of the Related Art Conventionally, in a steel wire rod rolling facility, billets are successively rolled and formed by several rough rolling mills and intermediate rolling mills, and a diameter of several mm is obtained by a finishing rolling mill arranged at the final stage. Process into a linear shape. The wire rod formed into the final shape is fed through a U-shaped or tubular guide trough to a device called a laying head disposed downstream of the finishing mill. At this time, the passing speed of the wire rod on the downstream side of the finish rolling mill is from several tens m / s to more than 100 m / s in high-speed equipment.

The laying head is a device for continuously deforming a wire fed at such a high speed into a ring shape. The structure is a cone shape having a pipe through which a wire is passed, and the head is rotated by a motor with a constant radius around the vertex of the cone. The fed wire is taken into the pipe at the fulcrum, and is discharged from the tip of the rotating head to be deformed into a ring shape.

[0004] An electric motor driven pinch roll is provided on the front surface of the laying head to draw a wire into the laying head. A straight path is provided between the finishing mill and the laying head in order to avoid as much as possible the surface of the product wire from being damaged by the high-speed contact between the inner surface of the trough and the product wire. Also, between these passages,
A product water cooling zone or the like is arranged to control and temper the temperature of the wire, and a certain distance is provided to secure a time required for passing the wire to control the temperature of the wire. Generally, the distance between the finishing mill and the laying head is 30
m or more in many cases.

[0005] In such a facility, the magnitude of the tension acting on the wire being passed between the finishing mill and the pinch roll often affects the shape of the ring discharged from the laying head. Are known. That is,
When the magnitude of the tension acting on the wire changes, the size of the ring changes, or the ring shape is distorted from a predetermined circular shape.

[0006] Since the ring-shaped wire rod after passing through the laying head is integrated as a coil into a product, the state of the ring shape is important as one of the product qualities.
In addition, if the ring shape is largely disturbed, rolling cannot be continued, resulting in mis-rolling. Therefore, a technique for controlling the tension acting on the wire rod in order to stabilize the ring shape is important in such equipment.

Conventionally, the tension acting on the wire between the finish rolling mill and the pinch roll is detected by detecting the load current or torque of the electric motor driving the pinch roll, calculating the tension value from the detected value, and further calculating the tension value. The speed of the pinch roll is controlled so that the calculated tension value becomes a predetermined constant value. In this control, the speed of the pinch roll has a constant lead speed with respect to the speed of the finishing mill, and the value of the lead speed is changed based on the calculated tension value. That is, generally, the tension acting on the wire is minus (compression side).
A certain amount of pulling force is applied so as not to fluctuate.

However, when the tail end of the wire is removed from the finish rolling mill, the tension value generated by the lead speed of the pinch roll becomes zero, the tension value fluctuates, and the wire at the tail end portion of the wire rod passes through. In the above method, the tension cannot be controlled by the above method.

In order to solve such a problem, control is sometimes performed to accelerate the speed of the pinch roll at a constant rate after the tail end of the wire is removed from the finishing mill.
When the speed of the wire is accelerated, an inertial force proportional to the acceleration acts due to the mass of the wire, so by applying this control, tension is applied to the wire even if the tail end of the wire has passed through the finishing mill. Somewhat more action can be taken than without acceleration.

[0010]

However, in the above-described method of accelerating the speed of the pinch roll, it is necessary to change (accelerate) the circumferential motion speed of the laying head in synchronization with the change in the speed of the pinch roll. Therefore, there are the following problems, and in many cases, a sufficient effect cannot be obtained. (1) Due to the limitation of the acceleration capability of the laying head, it is not possible to change the speed of the pinch roll with an acceleration sufficient to apply a sufficient tensile force to the wire.

That is, since the laying head has a large moment of inertia due to its structure, it cannot perform acceleration at a high mechanical strength rate. (2) By changing the speed of the racing head,
The state of contact between the inner surface of the pipe inside the laying head and the wire passing through it changes, and even if the tension value acting on the wire can be controlled to a predetermined value, the ring changes due to a new factor due to the speed change. Shape distortion may occur.

Therefore, conventionally, the portion after the tail end of the wire rod has passed through the finish rolling mill, that is, the tail end of the product coil having the length from the finishing rolling mill to the laying head, has the other portion. The shape often deteriorates as compared with the ring shape, and when the disturbance is remarkable, it may be necessary to remove the portion in a later step.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has the following configuration. That is, in a wire rod finishing equipment that has a wire rod finishing rolling mill that rolls a material into a linear shape and a laying head that forms a wire that has passed through the wire rod finishing roll into a ring shape, the wire rod finishing mill and the laying head And an electromagnet device for generating a predetermined tension in the wire by supplying a magnetic force to the wire that has exited the wire finishing mill, and the action of the electromagnet device avoids disturbance of the ring shape of the wire.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a tension control device of a wire rod rolling facility according to the present invention. In the drawing, 1 is a finishing rolling mill for steel wire rods, 2 is a laying head, and 3 is a pinch roll for drawing potential into the laying head. Although not shown, each of these devices is driven by a motor whose rotation speed is controlled by a variable speed device. Reference numeral 4 denotes a wire rod which has been stretched to a final shape by passing through a finish rolling mill. This product wire is linearly passed through the guide trough 5 from the finishing mill to the laying head, and is formed into a ring shape by passing through the laying head.

[0015] The trough (5) transfers the wire fed from the finishing mill to the pinch roll (3) in front of the laying head.
It is a guide trough to guide. The cross section is usually U-shaped or cylindrical, and the material is steel plate.

Reference numeral 6 denotes an electromagnet device, and the finishing mill 1
A plurality is arranged along the above-mentioned straight trough between the pinch rolls 3 and 3. The configuration of the electromagnet device 6 will be described later.

FIGS. 2 (a) and 2 (b) show arrows A in FIG.
It is a diagram showing a cross-sectional shape as viewed from the -A direction. FIG. 3A shows a case of a U-shaped trough, and FIG. 3B shows a case of a cylindrical trough. The electromagnet device 6 is installed below the trough 5, and when excited, causes its magnetic force to act on the wire 4 via a steel plate trough.

Until the tail end of the wire passes through the finishing mill, as described in the related art, by controlling the speed of the pinch roll 3 based on the calculated tension value, the tension in the passing material is reduced. It is controlled to be constant.

Next, the tail end of the wire is tracked using a hot mass detector described later, and the timing at which the tail end passes through the finishing mill is predicted. That is, the detecting device 61 shown in FIG. When the timing of exiting is predicted, the excitation power supply control device 62 controls the excitation power supply
Is supplied with a predetermined current. Then, the electromagnet 64 generates a predetermined magnetic force. Since the electromagnet device 6 generally has an excitation time constant of about 1 second, the excitation current rises from 0 to a predetermined value at a timing earlier than the end loss by the time constant. For this purpose, a hot lump detector (HMD) (not shown) is provided in front of the finishing mill, and the tail end of the wire is tracked by a signal passing through the hot lump detector.

At the same time, the speed of the pinch roll 3 is fixed to the speed at that time when the speed correction by the tension control is completed at the timing of the trailing edge removal. Due to the action of the magnetic force of the electromagnet device 6, the wire passing resistance of the wire passing therethrough increases, so that a pulling force is generated in the wire on the upstream side of the pinch roll 3.

The exciting current value for the electromagnet 64 may be fixed to the rated current value of the electromagnet. However, an appropriate value is determined according to the type (steel type and size) of the wire to be passed, and control is performed to preset the value. Is more desirable to stabilize the tension value.

Furthermore, the current value of the pinch roll in the tension control, which was performed until the tail end of the wire 4 was removed from the finish rolling mill 1, and the calculated tension value at the timing when the tail end of the wire 4 was removed from the finish rolling mill 1. Is stored, and the exciting current value is determined based on the stored value. The value of the tension value generated in the wire 4 after the tail end of the wire 4 has passed through the finishing mill 1 is a function of the magnitude of the magnetic force acting on the wire 4, that is, the exciting current value. Then, the exciting current value is determined so that the value of the tension value generated in the wire 4 coincides with the stored calculated tension value, and the exciting current value is controlled. If the exciting current value of the electromagnet 64 is controlled as described above, it is possible to more effectively suppress the fluctuation of the tension when the wire 4 comes off from the finishing mill 1.

According to this embodiment, the finishing mill 1
Even after the wire 4 comes off from the wire, a predetermined tension can be applied to the wire 4 by the action of the magnetic force of the electromagnet device 6, so that the ring shape of the wire discharged from the laying head 2 can be stably fixed. Can be kept.

In particular, according to this embodiment, there is no problem in the conventional method of accelerating the speed of the pinch roll 3 as described below. (1) In the conventional method of accelerating the speed of the pinch roll 3, there is a problem that a sufficient tension cannot be applied to the wire rod due to the restriction of the acceleration rate of the learning head. However, according to this embodiment, The tension value can be controlled only by controlling the exciting current of the electromagnet 64. (2) Since there is no need to change the speed of the laying head, the ring shape of the wire is not disturbed due to the change in speed of the laying head.

In the above-described embodiment, the electromagnet 64 is arranged at the lower part of the trough. However, the arrangement of the electromagnet 64 does not need to be particularly limited to the lower part of the trough, and may be provided at the upper part.
Further, the steel sheet trough itself may be magnetized and used as the electromagnet 64.

[0026]

As described above, according to the present invention, the product having the length after the tail end of the wire rod 4 has passed through the finishing mill 1, that is, the distance from the finishing mill to the laying head. Since a predetermined rear tension is applied to the coil tail end by the electromagnet device 6, the wire 4 can be uniformly formed into a favorable ring shape.

[Brief description of the drawings]

FIG. 1 is an equipment configuration diagram for explaining the present invention.

FIG. 2 is a sectional view in the direction of the arrow in FIG.

FIG. 3 is a block diagram of an electromagnet device used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Finishing rolling mill 2 ... Laying head 3 ... Pinch roll 4 ... Wire 5 ... Trough 6 ... Electromagnet device 61 ... Detection device 62 ... Excitation power supply control device 63 ... Excitation power supply device 64 ... Electromagnet (coil)

Claims (3)

[Claims] 1. A wire rod finishing machine comprising a wire rod finishing mill for rolling a material into a wire and a laying head for forming a wire rod having passed through the wire rod finishing machine into a ring shape. And an electromagnet device for generating a predetermined tension on the wire by supplying a magnetic force to the wire exiting from the wire finishing mill and provided between the wire rolling mill and the tension control of the wire rolling equipment. apparatus. 2. The tension control device for a wire rod rolling plant according to claim 1, wherein the electromagnet device is provided below a trough for guiding the wire rod. 3. The tension control device according to claim 1, wherein the electromagnet device is provided above a trough for guiding the wire.