JPS6160211A - Method for controlling switch of wire rod distributing device - Google Patents

Abstract

PURPOSE:To minimize the generation of bend and flaw of a wire rod and to prevent the wire rod from jumping out of a rolling line by switching a distributing device at an optimum timing regardlessly of the changes of the cutting length and conveying speed of a wire rod and the change of a switching time of the distributing device. CONSTITUTION:The conveying speed V of a wire rod 10 and the allowable remaining length V, td of the tail end of a preceding wire rod 10A in a distributing device 16, are obtained. Next, the time when the cutting point of wire rod 10 passes through the device 16, is obtained from the conveying speed V and the cut length of the wire rod 10A or a succeeding wire rod 10B. And then, the switching of device 16 is started at the time when the front tip of a part of allowable remaining length V, td at the tail end of wire rod 10A arrives at the outlet of device 16, and the switching is finished while the tail end of material 10A is still remaining in the device 16.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a switching control method for a wire rod sorting device, and is particularly suitable for applying to a wire rod sorting device of a high-speed wire rod mill. The present invention relates to an improvement in a switching control method for a wire sorting device that sorts leading material and trailing material to different conveyance lines on the downstream side of a shear.

[Conventional technology]

As is well known, when wire rods, steel bar raw materials, etc. are rolled and formed by continuous rolling equipment having a large number of rolling mills, a shear such as a flying shear is installed next to the final stand of the rolling equipment. This shear is used for cutting the leading edge and trailing edge of the rolled forming material.
Furthermore, multiple cuts of the same material are performed, and the material cut by the shear is sent out to the next process by a wire sorting device such as a selector. When controlling the switching of the sorting device, generally, after detecting the material using a material detector such as a photocell,
A method of switching via a timer or the like is generally used. However, in these sorting and distribution methods based on material detection, when the moving speed of the material changes or the size of the material changes, an operator needs to change the time setting of the timer. In addition, with the improvement of continuous rolling technology in recent years, the rolling speed has become faster, the width between the maximum speed and the minimum speed has become wider, and factors such as the distance m between the shear and the distribution device have become more important. Considering this, it is extremely dangerous to start switching the distribution device based on the output of one material detector, and a large number of material detectors each having a corresponding speed are required. For this reason, the operator has to adapt to these changes immediately. Therefore, the operator must switch to a timer mode that is appropriate for the moving speed and calculate the time limit from when the output of the material detector is generated to when the switching command is given to the sorting device. This is the current setting. In addition, valves are generally used to operate the distribution device, and the operating time from the time a command is received to the completion of operation is not corrected, so extremely accurate next limit settings are required. . However,
Due to problems such as variations in the setting device itself, incorrect settings, and variations in commands, troubles tend to occur between successive materials and cutting materials in the sorting device, and between cutting materials and equipment. Damages such as damage to rolling equipment have occurred due to incorrectly discarded or switched rolling materials. In order to solve the above-mentioned problems, Japanese Unexamined Patent Application Publication No. 1983-1970
In 064, the moving speed of the rolled material is determined using pulses from a pulse generator installed on the roll drive shaft of the final stand in continuous rolling equipment, and this moving speed is used to determine the shear installed after the final stand and the fixed point behind it. The time it takes for the rolled material to pass through the shear is determined, and when the passing time has elapsed from the time when the shear passes the switching command point for the distribution device after startup, the pulse generator of the shear issues a start command to the distribution device. A method for switching a rolled wire sorting device has been proposed, which is characterized by performing optimal switching control.

[Problems to be solved by the invention]

However, in the past, in any case, the permissible switching time of the sorting device (hereinafter referred to as allowable switching time) was determined to be constant based on the passing time of the preceding material, so it was not always possible to perform optimal control. In other words, the switching time for the distribution H position generally changes due to changes in the pressure of the drive source and causes variations, and it is difficult to electrically or mechanically detect abnormalities in this switching time online. It is difficult. Therefore, in high-speed wire rod mills where the gap between the leading material and the trailing material cannot be sufficiently large when cutting the tip end of the wire rod, 1-1 tail end cutting, or division cutting, depending on the cutting length of the wire rod and the conveyance speed, the sorting device Due to a delay in switching or too early switching, the wire may be bent, or a - may occur in the wire.Furthermore, the wire may sometimes fly out of the line due to severe bending of the wire.

OBJECT OF THE INVENTION The present invention was made to solve the above-mentioned conventional problems, and it is possible to switch the wire sorting device at the optimum timing. An object of the present invention is to provide a switching control method for a wire sorting device that can prevent wire rods from flying out.

[Means to solve the problem]

The present invention provides a switching control method for a wire rod sorting device for sorting wire rods cut by a shear disposed on the exit side of a finishing rolling mill into different conveyance lines for leading material and trailing material on the downstream side of the shear. As shown in Fig. 1, there are a procedure for determining the conveyance speed of the wire rod, a procedure for determining the allowable remaining length of the tail end of the preceding material in the sorting device, and a procedure for determining the conveyance speed and the cutting length of the preceding material or the succeeding material. Next, the procedure for determining the time when the cutting point of the wire rod passes through the sorting device, and the switching of the sorting device is started when the tip of the residual allowable length portion of the tail end of the preceding material reaches the exit of the sorting device, and the switching of the sorting device is started. The above object is achieved by including the step of completing the switching while the tail end of the material remains in the sorting device. Further, in an embodiment of the present invention, the conveyance speed is determined from the rolling speed of the finishing rolling mill and the advance rate of the wire rod, and The tip cut is determined as either the conveyance speed determined from the time required for the wire to pass between the material detectors or the conveyance speed determined from the rotation speed of the roller equipment installed downstream of the sorting device. , appropriate conveyance speed can be obtained in both divisional cutting and tail end cutting. Further, in another embodiment of the present invention, the residual allowable length is
The remaining allowable length can be easily determined by multiplying the cut length of the preceding material by a correction coefficient. [Function] The present invention was made in view of the recent increase in speed and high automation of wire rod rolling. When switching the wire sorting device for sorting leading material and trailing material to different conveyance lines on the downstream side of The remaining allowable length is determined, and when the tip of the remaining allowable length portion of the tail end of the preceding material reaches the outlet of the sorting device, the sorting device is started to be switched, and the tail end of the preceding material remains in the sorting device. Since the changeover is completed while the changeover is still in progress, the wire sorting device can be changed over at an optimal timing taking into account the time required for the changeover. Therefore, it is possible to reliably prevent the wire from being bent, damaged, or coming out of the line.

[Embodiment 1] Hereinafter, an embodiment of a switching control device for a wire rod distribution device of a high-speed wire rod mill to which the present invention is adopted will be described in detail with reference to the drawings. FIG. 2 shows the control block and equipment arrangement of this embodiment, in which the wire rod 10 rolled by the finishing mill 12 is cut by the shear 14 and then placed on the downstream side of the shear 14. A sorting device 116 distributes and conveys leading materials and trailing materials before and after the cutting point to different conveying lines 18 and 20. The conveyance speed V of the wire rod 10 is converted into the rotation speed N of the finishing rolling mill 12 by a converter 24 based on a pulse signal from a pulse transmitter 22 attached to the end of the motor shaft of the finishing rolling mill 12, for example. It is input to the distribution control sacred treasure 26. The roll diameter setting device 28 is used for the finish rolling W1 currently in use.
The output of the roll diameter setting device 28 is input to the distribution controller 26. The advance rate setter 30 is for setting the advance rate ρ of the wire rod 10 at the exit side of the finishing rolling 1112, which is determined by the rolling schedule, and the output of the advance rate setter 30 is also determined by the shooting division controller. 26. The distributing machine 26 determines the finish rolling l based on the rotational speed N, roll diameter, and advance rate ρ based on the following formula.
112 The conveying speed of the wire 10 on the exit side, V, is calculated. V=πDN (1+ρ)...(1) Note that the method for determining the conveying speed V of the wire rod 10 is not limited to this, and two material detectors, for example, a hot metal Detectors (hereinafter referred to as HMDs) 32 and 34 are arranged a distance Lo apart, and the time f! from when the tip or tail end of the wire rod 10 passes the first HMD 32 until it reaches the second HMD 34 is f! By measuring ljo with the time counter 36, it is also possible to perform calculation detection within the distribution controller 26 based on the following equation. v - Lo / t o -< 2) It is also possible to directly detect the conveying speed V using, for example, a laser velocimeter. Furthermore, when the wire rod 10 passes through the sorting device 16 and proceeds further downstream, it is transported by roller equipment (not shown) such as a table roller, a vinch roll, and a reeler installed there. Therefore, in this case, it is also possible for the distribution controller 26 to take in the conveyance speed V from the roller equipment as an external signal. The distribution device 116 is structured to be driven by a cylinder 16A, and the cylinder 16A is reversibly driven by switching the direction of inflow of pressurized fluid or gas into the cylinder 16A using a solenoid valve 40. The tracking base point of the wire cutting point to which the conveyance line 18.20 is to be switched by the sorting device W116 is determined by the wire passing signal from the first HMD 32 located at a distance ML1 from the outlet of the sorting device 16, or by the wire passing signal from the shear 14. The cutting completion signal may be a blade position detector attached to the end of the motor shaft, for example, a pulse transmitter 38. In the immediate vicinity of the sorting device 16, a switching direction detector,
For example, when proximity switches 42, 44 are provided and the sorting device 16 is switched to the first conveyance line 181111J, the first proximity switch 42 outputs an ON signal, and conversely, the sorting device 116 is not switched to the second transport line 20 side, the second proximity switch 44 outputs an ON signal. and,
The switching time measuring device 46 measures the switching time of the distributing device 1 after the switching command signal is output from the distributing controller 26.
6 is from the first (or second) conveyance line to the second (or first)
The actual switching time until switching to the conveyance line is measured and input to the distribution controller 26. The allowable switching time of the distribution device 16 is calculated and set within the distribution controller 26, for example, as follows. For example, in the case of tip crop cutting, even if the switching is completed with the tail end portion of the preceding material remaining in the sorting device 16 to some extent, the preceding material can exit the sorting device 16 due to the advancing inertia force. Therefore, first, the allowable remaining length Lr in the image sorting device 16 is calculated and set. This residual allowable length Lr varies depending on the steel type of the wire rod 10, cutting length, conveyance speed, allowable flaws, degree of bending, etc., but for example, the cutting length Lc set by the cutting length setting device 50 and the correction coefficient Using the correction coefficient K set by the setting device 52, the product Lc- of both can be calculated and set. The sorting device 16 determines this residual allowable length Lr (=Lc-
It is necessary to perform the operation from the start of switching to the completion of switching within the range of K). That is, the allowable switching time Td of the sorting device 16 needs to satisfy the following condition based on the residual allowable length Lr and the conveying speed V of the wire 10. Td < L r /v (3) A detailed examination of the relationship in equation (3) yields the following. For example, cutting length Lc, switching time td, wire rod 1
Keeping the transport speed V of 0 constant, the correction coefficient K is set to 1 and K2.
．． 3 (K1>K2>K3), the residual allowable length Lr=Lc- in equation (3) will have the third
As shown in the diagrams (A>, (B), and (C), the length becomes shorter in sequence,
The switching start timing of the distribution device 16 is also delayed sequentially, and the situation at the time of completion of switching is as shown in FIG. 4(A), respectively.
As shown in (B) and (C). Here, in Figure 4 (C
) is -Ka when the preceding material 10A is not pinched by the distributing device 16, and the change is completed at the same time as the tail end of the preceding material 10A exits the distributing device 16, Td-(Lc/V)'K
This is a case where a holds true. However, actually setting such a correction coefficient to 3 is impossible due to variations in the required switching time td, and should not be set. Considering the case where the value of the correction coefficient becomes even smaller than 3, in this case, the minimum switching time tdmin of the distribution device 16
Since there is a limit to
There is a possibility that it will become I. If the sorting device 16 is activated for such an incorrectly set correction coefficient Kg (<K3), as shown in FIG. In other words, trailing material 1
Since the switching is completed after the tip of the 0B enters, for example, the first conveyance line 18, problems such as occurrence of cobbles in the sorting device 16 occur. The distribution controller 26 internally has a value of the required switching time of the distribution device 16, and performs calculation tracking in consideration of this required switching time td.
Outputs a switching command signal to 0. The switching time td is determined by the selector 54 and the number of times setter 5.
6 allows for appropriate changes and selections. That is, in the selector 54, it is possible to set the off mode, the average value control mode, or the previous switching time control mode, and when the off mode is selected, The allowable switching time Td is changed to the required switching time t.
d for arithmetic control. On the other hand, when the previous switching time control mode is selected, the distribution controller 26 uses the switching time measured by the switching time measuring device 46 as it is as the switching time td for the next switching, and performs calculation control. I do. Furthermore, when the average value control mode is selected, the number of switching times n set by the number setting device 56, the switching time td measured by the switching time measuring device 46 for every n switching times, ,t
From d2...tdn, calculate the average switching time tdm based on the following formula, and use it as the switching time 1d for the next switching. Performs ltI control. tdllll = (td+ +td2+...+tdn
) /n m (4) Since the switching time of the distribution device 16 also changes depending on the pressure fluctuation of the pressure fluid or gas that is its driving source, in this embodiment, the switching time of the solenoid valve 40
A pressure detector 58 is disposed in the pipe, and the pressure signal detected by the pressure detector 58 is transmitted to the distribution controller 26.
is input. Inside the distribution controller 26, a relational expression between the pressure determined in advance through experiments and the like and the switching time of the distribution device t16 is stored, and from this relational expression, the above-mentioned switching time td is corrected and the final value is determined. It also has a function that can be used as the standard switching time td. The display device 60 displays the switching time measured for each switching by the switching time measuring device 46, the switching required time td set inside the distribution controller 26, or This is for displaying the pressure detected by the pressure detector 58. The alarm 64 is activated when the switching time measured by the switching time measuring device 46 exceeds the required switching time td, or when the pressure of the drive source of the distributing device 16 decreases and the switching time R of the distributing device 16 is If it is predicted that it will take an abnormally long time, the allocation to judge these [pu control sacred treasure 26]
The purpose is to generate an alarm signal by the output of the The distribution controller 26 is composed of, for example, a microcomputer, and each of the functions described above is processed extremely quickly and accurately. The operation of the embodiment will be explained below. First, the case of a tip crop cut will be explained. 6(A') to (E) show that the tip of the wire 10 is cut by the shear 14, and the leading material 10A with a cutting length Lc is transferred to the first conveyance line 18, and the trailing material 10B is transferred to the second conveyance line 18. line 2
FIG. 2 is a diagram showing the operation transition of the wire rod 10 and the sorting device 16 when conveying the wire rod to the wire rod 10. First, when the wire rod 10 begins to be rolled in the finish rolling 1!12, the distribution controller 26 calculates and detects the conveying speed V based on the signal from the converter 24 based on the above equation (1). Since the cutting length Lc and the correction coefficient are set by the cutting length setting device 50 and the correction coefficient setting device 52, respectively, before the start of operation, for example, when the cut mode is selected by the selector 54, the above The distribution controller 26 is configured as described above (
3) Calculate the allowable switching time Td based on the formula, and set this as it is as the required switching time td. When the wire 10 reaches the shear 14, the shear 14 is activated and cuts the tip of the wire to a set cutting length Lc, as shown in FIG. 6(B). The distribution controller 26
receives a disconnection completion signal from the pulse transmitter 38;
Start tracking the cutting point. In the case of tip crop cutting, as shown in FIG. 6(C), the tip of the preceding material 10A has a residual allowable length Lr, that is, the tip has a length of V-td determined from the conveyance speed V and the required switching time td. Since it is necessary to start the switching when the cutting point reaches the exit surface of the shear 16, it is understood that the switching can be started when the cutting point advances L2-v-td from the shear 14. That is, the distance L that the cutting point travels from the completion of cutting to the start of cutting is expressed by the following equation. Lt=L2-V・td...(5) The distribution controller 26 counts the pulse signals output from the pulse transmitter 22 from the time of receiving the cutting completion signal, converts this into a distance, When the above-mentioned formula (5) is established, a switching command signal is output to the solenoid valve 40 to drive the cylinder 16△ (FIG. 6(D)), and finally the switching occurs within the required switching time td. The sorting device 1
6 to the second @ feed line 20 (Fig. 6 (
E)) In the switching process, the switching time is measured by the switching time measuring device 46, and if the switching time exceeds the required switching time td, an alarm signal is output to the alarm device 64. When this alarm occurs, the operator can check the abnormal element using the display 60 or the like and take countermeasures, such as resetting the correction coefficient K, for example. If the distance between the shear 14 and the sorting device 16 is <K, and the conveyance speed V of the wire 10 is fast, tracking of the cutting point may have started after receiving the cutting completion signal from the pulse transmitter 38. Control may not be in time. In this case, the tracking base point is set to the first HMD.
32. That is, the distribution controller 2
6, as shown in FIG. 6 (A>), the tip of the wire is connected to the
Tracking is started when the wire rod 10 passes through the MD 32, and after being conveyed, the wire rod 10 is cut by the shear 14 and divided into a leading material 10A and a trailing material 10B each having a length Lc. Therefore, inside the distribution controller 26, when the tip of the wire 10 passes the first HMD 32,
Tracking is performed by calculating and determining that the cutting point that should originally be tracked is located behind the first HMD 32 by a distance of the cutting length Lc. Therefore, the tip of the wire is connected to the first HMD.
The distance Lt- that the tip of the wire travels after passing through 32 until the distribution controller 26 outputs a switching command is expressed by the following equation in consideration of the residual allowable length v-td. Lt −=Lt+Lc V ·td−('6) In this case, the distribution controller 26 receives the wire passing signal from the first HMD 32, and the pulse transmitter 2
2, the input pulse signals are counted, and this is converted into a distance. When the above-mentioned equation (6) is satisfied, a switching command signal is outputted, and the photographing separation device 16 is switched. Next, the case of split cut will be explained. In the case of this split cut, the basic concept of switching timing control of the distribution device W116 is the same as in the case of the tip crop cut. That is, the cutting length Lc is set by the cutting length setting device 50, and the correction coefficient is set by the correction coefficient setting device 52. Also, the required switching time td is
The selection is made by the selector 54. However, at the time of split cutting, it is possible that the tip of the wire has already passed through the sorting device 16 and is further conveyed by roller equipment such as table rollers, pinch rolls, and reelers installed downstream, so in this case Alternatively, the conveyance speed V can be calculated and detected from the roller equipment. The distribution controller 26 preliminarily determines the distance 1. -t is calculated, tracking is started upon reception of the cutting completion signal from the pulse transmitter 38, and the preceding material 1
It is determined from an external signal whether the equipment conveying 0A is a finishing rolling mill 12, a table roller, a pinch roller, a reeler, or other roller equipment (not shown), and a pulse transmitter installed in each equipment is used. Among the devices, the pulse signals from the pulse transmitters of the corresponding equipment are counted, and when the distance is converted to 1 t, a switching command signal is output and the distribution device 16 is switched. Next, the case of a tail end crop cut will be explained. 7(A) to (E) show the wire rod 10 when the tail end portion of the wire rod 10 is subjected to FJJ with the shear 14 and the trailing material 10B having a cutting length Lc− is conveyed to the first conveyance line 18. 2 is a diagram showing the operation transition of the sorting device 16. FIG. In the case of this tail end crop cut, the cutting length setting device 5
What is set as 0 is the tail end cutting length Lc=, but since the residual allowable length Lr is the length allowed for the tail end portion of the preceding material 10A, the cutting according to the above formula (3) The length Lc is
This is the length of the preceding material 10A, and the correction coefficient also has a value for the preceding material 10A. Furthermore, in the case of this tail end crop cut, the wire rod tail end is subjected to the finish rolling t! 112 completely, the conveyance speed (2) is determined by the rotation speed of roller equipment (not shown) such as table rollers, pinch rolls, and reelers. Based on the above-mentioned formula (5), the shooting classification controller 26
The distance 11tLt is calculated in advance, and as shown in FIG. 7(B),
Equipment that starts tracking upon reception of the cutting completion signal from the pulse transmitter 38 and is transporting the preceding material 10A;
For example, by counting pulse signals from a pulse transmitter (not shown) attached to a table roller, pinch roll, or reeler, and converting this into a distance, the time point when Lt is reached, as shown in Figure 7 (C). Output the switching command signal with
Switch the distribution device [16]. Even in the case of this tail end crop cut, if the distance between the shear 14 and the sorting device 16 is short and the conveyance speed V of the wire 10 is fast, the tracking base point can be set to the first HMD 32. In this case, the distribution controller 26 determines that when the tail end of the wire passes the first HMD 32, the cutting point to be tracked is already ahead of the 18th MD 32 by a distance of the tail end cutting length Lc. , the tip of the remaining allowable length Lr to start switching is calculated and determined to be further forward by V·[d, and tracking is performed. Therefore, the tail end of the wire is the 11th-IM
Distance 11Lt that the wire tail end travels after passing D32 until the distribution controller 26 outputs a switching command
'- is expressed by the following formula. Lt=-=L+Lc--v-td・''(7) In this case, the distribution controller 26 is attached to the table roller, pinch roll, and reeler from the time when it receives the wire passing signal from the first HMD 32. Count the pulses from the pulse transmitter, convert this into a distance, and calculate the distance as described above (
7) When the formula is established, a switching command signal is output to switch the sorting device 16. In this embodiment, since a display 60 and an alarm 64 are provided, if an abnormality occurs in the switching timing or switching time of the sorting device 16, the alarm 64
Not only can this be detected by the operation of the distributing device 16-9, but also whether the cause is a pressure change in the drive source of the distribution device 16-9, electrical or mechanical, or a setting error by the operator. You can immediately know from the display 60 whether the Further, by utilizing this function and switching the distribution device 16 in a simulated manner before operation, abnormalities can be detected in advance. Effects of the Invention As explained above, according to the present invention, it is possible to always achieve optimum results regardless of changes in the cutting length of wire or steel bar materials, changes in conveyance speed, or changes in switching time due to changes in the state of the drive source of the sorting device. The sorting device can be switched at a suitable switching timing. Therefore, bending and damage to the wire can be minimized, and the wire can be prevented from flying out of the line. Therefore, it has excellent effects such as improving the workability and completeness of the continuous rolling operation and improving productivity through stable operation.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the gist of a switching control method for a wire sorting device according to the present invention, and FIG. 2 is a configuration of an embodiment of a switching control device for a wire sorting device of a high-speed wire rod mill to which the present invention is adopted. Block diagram showing FIG. 3 (A), (B),
(C) is a plan view showing a comparison of the relationship between the cut length of the wire and the residual allowable length for detailed explanation of the present invention;
Figures (A), (B), and (C) are also flat views showing a comparison of the residual tolerance of the preceding material and the state of passage through the sorting device;
Fig. 5 is a plan view showing the passing state of the sorting device when the remaining allowable length of the preceding material is too short, and Fig. 6 (
A) to (E) are route diagrams showing the switching operation of the sorting device and the transition of the conveyance state of the wire during the tip crop cutting in the above embodiment, and FIGS. 7(A) to (E) are the same for the tail end cropping. It is a route map which shows the switching operation of the sorting device at the time of cutting, and the transition of the conveyance state of the wire. DESCRIPTION OF SYMBOLS 10... Wire rod, 10A... Leading material, 10B... Following material, 12... Finishing rolling machine, 14... Shear, 16... Sorting device, 18.20... Conveying line , 22.38...Pulse transmitter, 24...Converter, N...Rotation speed, 2
6...Distribution controller, 30...Advanced rate setting device, ρ...Advanced rate,■・
...Conveyance speed, 32.34...Hot metal detector (HMD), 3
6... Time counter, 50... Cutting length setter, Lc, Lc-... Cutting length, 52... Correction coefficient setter, K... Correction coefficient, [
r...Remaining allowable length.

Claims (3)

[Claims] (1) In a switching control method of a wire rod sorting device for sorting wire rods cut by a shear disposed on the exit side of a finishing rolling mill to different conveyance lines for leading material and trailing material on the downstream side of the shear, the wire rod A procedure for determining the remaining allowable length of the trailing end of the leading material in the sorting device; From the conveying speed and the cutting length of the preceding material or the following material, the cutting point of the wire is determined by the sorting device. The procedure for determining the passing time, and the switching of the sorting device is started when the tip of the residual allowable length portion of the tail end of the preceding material reaches the outlet of the sorting device, and the tail end of the preceding material remains in the sorting device. While I'm here,
A method for controlling switching of a wire sorting device, comprising: a procedure for completing the switching; and a method for controlling switching of a wire sorting device. (2) The above-mentioned conveyance speed is calculated from the rolling speed of the finishing rolling mill and the advance rate of the wire rod, and is the conveying speed determined from the rolling speed of the finishing rolling mill and the advance rate of the wire rod, and the speed at which the wire rod passes between the plurality of material detectors installed between the finishing rolling mill and the shear. Switching of the wire rod sorting device according to claim 1 to either the conveyance speed determined from the required time or the conveyance speed determined from the rotation speed of the roller equipment disposed downstream of the distribution device. Control method. (3) A switching control method for a wire sorting device according to claim 1, wherein the residual allowable length is determined by multiplying the cutting length of the preceding material by a correction coefficient.