Optimization control method for large-size tail speed-up in wire rod

Abstract

The application provides a large-size tail section speed-up optimization control method for a wire rod, develops a reducing sizing machine, pinch rollers and a wire spooling machine relay speed-up function, and realizes automatic switching of different specifications and different speed-up modes. By using the new control method, the influence of the tail section speed-up on the finished product circle shape is eliminated, the production stability is improved, the restriction of the mechanical capacity of the reducing sizing machine, the pinch rollers and the wire spooling machine on the production of the super large-size product is reduced, the production efficiency is improved, the service life of the reducing sizing machine is prolonged, and the maintenance cost investment is reduced.

Description

Technical Field

[0001] It belongs to the field of automatic control technology and involves the automatic control technology for the speed increase of large-diameter tail sections in high-speed wire rods. Background Technology

[0002] A high-speed wire rod production line typically consists of a walking beam furnace, roughing mill, intermediate mill, pre-finishing mill, finishing mill, sizing mill, pinch rolls, wire rod feeder, Stellmore wire, and PF wire. After being heated in the furnace, the steel billet is rolled into finished products by a high-speed wire rod mill. Following appropriate temperature control, the finished product is then drawn into coils by the wire rod feeder.

[0003] In wire rod production, when rolling medium to large-sized products with a diameter of φ16.0 or larger, due to the relatively low finished product speed and the large load on these products, a tail-end speed-up function is used in the rolling control to ensure smooth exit of the rolled piece from the coiler. On production lines with a maximum production size of φ25.0, a common method is to synchronously increase the speed of the reducing and sizing mill, pinch rolls, and coiler when the rolled piece exits the last working mill before the reducing and sizing mill, provided the exit speed is less than 22 m / s. Newer wire rod production lines and some wire coil composite production lines in recent years also use only the synchronous speed-up method for the pinch rolls and coiler.

[0004] Both domestic and international wire rod mills commonly face issues with production stability and coil shape problems in large-diameter wire rod production. For example, the literature "Wire Spinning Control of Large-Diameter Wire Coils in High-Strength Wire Rods" (Rolling Steel, 2008, No. 3) describes problems encountered during the production of large-diameter wire rods, including tail dragging, small coils with twisting, out-of-roundness at the head, and excessive coil height. These issues directly impacted production stability and became a bottleneck in the production of large-diameter wire rods. The largest production size described in the article is φ20.0, using a method of synchronous speed increase for the pinch rollers and wire spinneret. The article describes improvements made through optimization of the control parameters of the pinch rollers and wire spinneret. Another example is the literature "Tail Spinning and Coil Shape Control of Large-Diameter Wire Rods in High-Strength Wire Rods" (Southern Metals, 2022, No. 244), which describes a domestic high-strength wire rod mill experiencing problems such as tail-end stagnation and large coils when producing large-diameter wire rods with diameters of φ15mm and above. These issues directly affect production stability and also impact processing costs and appearance quality control, becoming a bottleneck in the production of large-diameter wire rods. The maximum production specification described in the article is φ25.0, which adopts a synchronous speed-up method for the pinch roller and the spinning machine. The article describes how the existing problems were solved by optimizing the speed-up control logic and process parameters of the pinch roller.

[0005] The patent "A control method and control system for preventing wire tail residue in the wire spinning machine" (Chinese Patent Publication No. CN106269929B) proposes a method to prevent wire tail residue in the wire spinning machine by determining whether the shear located before the reducing and sizing mill has issued a closing command. When a closing command is issued, a wire tail signal is generated, which drives the pinch rolls and the wire spinning machine to continue operating at a preset rotation speed. The effects described in the literature are: it can solve the problem of preventing wire tail residue in the rolling channel, pinch rolls, and wire spinning machine when rolling large-diameter wire rods, reducing scrap steel processing time, avoiding frequent replacement of the wire spinning tube, improving production efficiency, and promoting safe production. This technology mainly addresses the problem of preventing wire tail residue in the wire spinning machine after the shear before the reducing and sizing mill closes following an abnormality in the production of large-diameter wire rods.

[0006] The patent "Method for Preparing 28mm Diameter Wire Rods Using a High-Speed ​​Wire Rod Production Line" (Chinese Patent Publication No. CN103372565 B) proposes a method for preparing 28mm diameter wire rods using a high-speed wire rod production line. The rod is fed into a coiling mill by pinch rollers and coiled to form the wire rod product. During the coiling process, the speed increase rate of the reducing mill, sizing mill, pinch rollers, and the tail end of the coiling mill is set to 1.14–1.15 m / s². This technology also employs a synchronous speed increase method for the reducing and sizing mill, pinch rollers, and coiling mill. However, the synchronous speed increase of the reducing and sizing mill, pinch rollers, and coiling mill when the rolled piece leaves the last working mill before exiting the reducing and sizing mill has a certain impact on the shape of the finished coil due to the long speed increase time. Furthermore, in ultra-large specification production, the mechanical capacity of the reducing and sizing mill often results in small coils at the tail end, and the service life of the mechanical transmission equipment is short. Summary of the Invention

[0007] The method for optimizing the speed increase at the tail of large-diameter wires in this invention consists of the following steps, and the flowchart is attached. Figure 2 illustrate:

[0008] A method for optimizing and controlling the speed increase at the tail end of large-diameter wires, with wire diameters ranging from φ15mm to φ30mm, and the process flow in the high-speed zone of the wire is as follows:

[0009] Medium and large specification wire rod - HMD1 - finishing mill - HMD 2 - HMD 3 - reducing and sizing mill - HMD 4 - HMD5 - pinch rolls - wire rod feeder - forming coil. The tracking signal at the tail of the rolled piece starts from HMD1. The detector participates in the tracking of the tail of the rolled piece. A tail speed-up method is adopted in the rolling control. Its characteristic is that...

[0010] 1) The sizing mill, pinch roll, and spinning mill participate in the tail speed increase to achieve the relay speed increase function of the sizing mill, pinch roll, and spinning mill;

[0011] The tail acceleration method includes two modes to choose from:

[0012] If the rolled finished product size is smaller than the size threshold value one, that is: φ15mm-φ22mm, then

[0013] Select the first tail speed-up mode: that is, only the pinch roller and the spinning machine participate in the tail speed-up;

[0014] If the finished rolled product is larger than or equal to the specification threshold value two: φ23mm-φ30mm, then

[0015] Select the second tail speed-up mode, where the sizing mill, pinch rolls, and spinning mill all participate in the tail speed-up simultaneously.

[0016] After the tail of the rolled piece leaves the spinning mill, the pinch rolls and the spinning mill slow down and return to the normal rolling speed.

[0017] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0018] Select the first tail acceleration mode: Set the sizing mill acceleration slope I to zero;

[0019] HMD5 indicates that after the tail of the rolled piece leaves the wire spinneret, the pinch rolls and wire spinneret slow down and return to normal rolling speed.

[0020] According to the present invention, when rolling medium and large specification wire products with a diameter of φ16.0 or above, since the finished product speed is relatively low and the load of the specification products is relatively large, a tail speed increase function is adopted in the rolling control to ensure that the tail of the rolled piece is smoothly ejected from the wire ejector.

[0021] For example, the finished product speed for φ19 specification is 15.2m / s, and the pinch roller and spinning machine operate at 7m / s respectively. 2 8m / s 2 The acceleration is directed toward the target speed of 28 m / s. The acceleration slope I of the sizing and reducing mill is set to zero, meaning that the sizing and reducing mill does not participate in the tail speed increase, and only the pinch roller and the spinning mill participate in the tail speed increase.

[0022] Step 1, parameter table, and step 3, tail speed selection are newly developed control functions of this invention. The control program automatically calls up parameters such as the target speed and acceleration slope required for tail speed according to the finished product size specifications, reducing manual intervention and realizing automatic switching between different speed-up methods for different specifications.

[0023] Steps 4 and 5 are newly developed control functions of this invention, which realize the relay speed-up function of the sizing machine, pinch roller, and spinning machine.

[0024] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0025] If the finished rolled product is larger than or equal to the specification threshold value two, which is φ23mm-φ30mm, then

[0026] Select the second tail acceleration mode, where the sizing mill, pinch roll, and spinning mill all participate in the tail acceleration. In this mode, the acceleration slope I of the sizing mill is set to 0.5-1.1.

[0027] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0028] Establish an index table of control parameters related to tail acceleration corresponding to wire specifications:

[0029] In the control program, an index table of control parameters related to the tail acceleration corresponding to the wire specifications is established. These control parameters include:

[0030] The target speed I is the speed at which the reducing mill, pinch rolls, and wire drawing machine simultaneously accelerate from the designed finished product speed according to the acceleration slope I after the tail of the rolled piece leaves the finishing mill. The speeds of the three components remain synchronized. If the target speed has already been reached before the tail of the rolled piece leaves the reducing mill, then the target speed is maintained.

[0031] Target speed II is the target speed at which the pinch rolls and wire feeder accelerate from target speed I after the tail of the rolled piece leaves the reducing mill, according to acceleration slope II. If the target speed has been reached before the tail reaches HMD5, the target speed is maintained.

[0032] Acceleration slope I is the acceleration slope at which the tail of the rolled piece accelerates from the designed finished speed towards the target speed I after leaving the finishing mill.

[0033] Pinch roll acceleration slope II is the acceleration slope at which the pinch rolls accelerate from target speed I to target speed II after the tail of the rolled piece leaves the reducing mill.

[0034] The acceleration slope II of the wire spinneret is the acceleration slope at which the wire spinneret accelerates from target speed I towards target speed II after the tail of the rolled piece has disengaged from the reducing and sizing mill.

[0035] The distance S from the sizing mill outlet to the spinning mill is fixed.

[0036] S = (Target velocity I + Target velocity II) × T / 2

[0037] Target velocity II = Target velocity I + Acceleration slope II × T

[0038] T: The time it takes for the tail of the rolled piece to travel from the sizing mill exit to the wire drawing machine.

[0039] As mentioned above, the target speed I is the target speed at which the sizing mill, pinch rolls, and wire spinner simultaneously accelerate from the designed finished product speed according to the acceleration slope I after the tail of the rolled piece leaves the finishing mill. The speeds of the three are kept synchronized. If the target speed has been reached before the tail of the rolled piece leaves the sizing mill, the target speed is maintained.

[0040] The exit speed of the reducing and sizing mill is the finished product speed. Between the time the rolled piece leaves the finishing mill and the time it leaves the reducing and sizing mill, the reducing and sizing mill, pinch rolls, and wire spinneret simultaneously accelerate from the designed finished product speed towards the target speed I according to an acceleration slope I, maintaining synchronization among the three speeds. The purpose of this relay acceleration is primarily to address the insufficient acceleration capacity of the reducing and sizing mill, pinch rolls, and wire spinneret. The equipment capacity of the pinch rolls and wire spinneret is only sufficient for specifications below φ23mm, where only the pinch rolls and wire spinneret participate in the tail-end acceleration. By using the target speed I and participating in the tail-end acceleration of specifications above φ23mm through the low slope of the reducing and sizing mill, the load on the reducing and sizing mill during acceleration is reduced, extending the service life of the reducing and sizing mill. Furthermore, it compensates for the insufficient equipment capacity of the pinch rolls and wire spinneret, reducing the constraints of the mechanical capacity of the reducing and sizing mill, pinch rolls, and wire spinneret on the production of ultra-large specifications.

[0041] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0042] Select the first tail acceleration mode:

[0043] The target speed I is equal to the setpoint of the reducing and sizing mill outlet speed. The reducing and sizing mill does not participate in speed increase.

[0044] Target speed II (23-28),

[0045] Acceleration slope I: 0,

[0046] Pinch roll acceleration slope II (5.5-9.5),

[0047] The acceleration slope of the spinning machine is II (5.5-9.5).

[0048] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0049] When selecting the second tail acceleration mode

[0050] Target speed I (12-17),

[0051] Target speed II (23-28),

[0052] Acceleration slope I (0.3-1.2),

[0053] Pinch roll acceleration slope II (5.5-9.5),

[0054] The acceleration slope of the spinning machine is II (5.5-9.5).

[0055] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0056] After HMD2 determines that the tail of the rolled piece has left the finishing mill, the sizing mill, pinch rolls, and wire spinner simultaneously begin to accelerate toward the target speed I according to the acceleration slope I.

[0057] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0058] After the HMD4 determines that the tail of the rolled piece has left the reducing and sizing mill, the reducing and sizing mill begins to decelerate, and the pinch rolls begin to accelerate toward the target speed II according to the pinch roll acceleration slope II; at the same time, the control system outputs a compensation value of 100% of the rated torque, which is directly superimposed on the torque setpoint of the frequency converter cabinet, and the spinning machine begins to accelerate toward the target speed II according to the spinning machine acceleration slope II.

[0059] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0060] After the tail of the rolled piece leaves the reducing and sizing mill, the reducing and sizing mill begins to decelerate, the pinch roll accelerates at the pinch roll acceleration slope II, and the wire spinner accelerates towards the target speed II at the wire spinner acceleration slope II.

[0061] The present invention provides a method for optimizing the speed increase control of the tail section of large-diameter wires, characterized in that:

[0062] Torque compensation for the spinning machine is used to improve the response of the spinning machine. The torque compensation value of the spinning machine is directly superimposed on the torque setpoint of the frequency converter cabinet. An adjustable advance is set for the input time to achieve a smooth transition of the wire rod circular shape between the two speed-up stages.

[0063] This invention proposes an optimized control method for the tail-end speed increase of large-diameter wire rods. It develops a relay speed increase function involving the sizing mill, pinch rollers, and coil spinneret, enabling automatic switching between different speed increase methods for different specifications. By using this new control method, the impact of tail-end speed increase on the finished product coil shape is eliminated, improving production stability. Simultaneously, it reduces the constraints imposed by the mechanical capabilities of the sizing mill, pinch rollers, and coil spinneret on the production of ultra-large-diameter products, increasing production efficiency, extending the service life of the sizing mill equipment, and reducing maintenance costs. Attached Figure Description

[0064] Figure 1 The diagram shows the process layout for the high-speed zone of wire rod production.

[0065] Figure 2 The diagram shown illustrates the acceleration at the tail of the wire.

[0066] Figure 3 The diagram shown is a flowchart of the speed-up control process at the tail of the wire.

[0067] Figure 4 The table shown is an index of control parameters related to the acceleration at the tail end of a wire rod factory.

[0068] Figure 5 The figure shows the improved φ22mm specification control curve of a certain wire factory.

[0069] Figure 6 The figure shows the improved φ25mm specification control curve of a certain wire factory.

[0070] In the diagram, the HMD1-5 hot metal detectors are used to track the head and tail of the rolled piece. HMD1 is located at the entrance of the finishing mill and is used to determine whether the rolled piece has entered the finishing mill; HMD2 is located at the exit of the finishing mill and is used to determine whether the rolled piece has left the finishing mill; HMD3 is located at the entrance of the reducing and sizing mill and is used to determine whether the rolled piece has entered the reducing and sizing mill; HMD4 is located at the exit of the reducing and sizing mill and is used to determine whether the rolled piece has left the reducing and sizing mill; HMD5 is located in front of the wire drawing mill and is used to determine whether the head or tail of the rolled piece has arrived at or left the wire drawing mill. Detailed Implementation

[0071] The present invention will be described in detail below with examples.

[0072] This invention was implemented in a wire factory.

[0073] The main rolling line of this wire rod mill adopts a typical configuration of "high-speed wire rod mill + horizontal wire rod extruder". When rolling large-size products, when the exit speed of the reducing mill is less than 22 m / s, the reducing mill, pinch rolls, and wire rod extruder synchronously increase their speed when the rolled piece leaves the last working mill before the reducing mill. This wire rod mill is currently the only manufacturer using a wire rod extruder to produce sizes larger than 27 mm, placing it at a leading level in large-size rolling in China. However, because the reducing mill reuses the original finishing mill's large motor, speed limitations (maximum speed 1550 rpm, original motor 1700 rpm) prevent some sizes from meeting the minimum speed requirement for tail-end acceleration when using small roll diameters. Furthermore, with the significant drop in wire rod extrusion temperature after low-temperature rolling, small tail loops frequently occur during ultra-large-size production due to the mechanical limitations of the reducing mill unit, hindering further expansion of large-size products. Because the speed increase begins on the last work stand before the sizing mill at the tail end of the rolled piece, there is a significant difference in the shape of the roll within one-fifth of its length, and the temperature of the rolled piece is significantly higher than that of the section without speed increase, affecting the uniformity of quality. Furthermore, the frequent speed increases and decreases of the sizing mill also affect the service life of the main drive equipment. The hardware for the tail-end speed increase control system in this wire rod mill was entirely provided by ABB, including the computer control system and the drive control system. The computer control system mainly consists of an ABB AC800PEC controller and an 800XA workstation. The AC800PEC controller performs a large number of complex logic and mathematical calculations in a short time and accurately measures relevant data. The 800XA is mainly used for inputting control parameters. The sizing mill drive control system is an ABB LCI medium-voltage frequency converter. The pinch roll and coiler drive systems are ABB ACS880 multi-drive frequency converters.

[0074] 1) Establish an index table of control parameters related to tail acceleration.

[0075] A wire rod mill uses a collective drive system for its reducing and sizing machine. The speed ratio of the frame is adjusted via a clutch in the reduction gearbox. Different clutch positions are configured according to different product specifications, and each specification has a corresponding clutch procedure number. Therefore, the specification can be determined by the clutch procedure number. An index table of tail-end acceleration control parameters corresponding to the wire rod specifications is established in the control program, including target speed I, target speed II, acceleration slope I, pinch roll acceleration slope II, and spinneret acceleration slope II, as shown in the attached table. Figure 3 As shown.

[0076] 2) Determining if the tail-end acceleration function is engaged

[0077] If the set value of the sizing mill exit speed is lower than the threshold value l (22m / s) for the tail speed boost function, then the tail speed boost function for the rolled piece will be activated.

[0078] 3) Tail-end acceleration mode selection

[0079] If the rolled finished product size is smaller than the size threshold value l (φ23mm), the first tail acceleration mode is selected, meaning only the pinch rolls and the spinning mill participate in the tail acceleration, while the reducing and sizing mill does not. If the rolled finished product size is greater than or equal to the size threshold value 1, the second tail acceleration mode is selected, meaning the reducing and sizing mill, the pinch rolls, and the spinning mill all participate in the tail acceleration. The tail acceleration mode selection is automatically achieved through control parameters; that is, if the reducing and sizing mill does not participate in the tail acceleration, the acceleration slope I is set to zero.

[0080] 4) After the tail of the rolled piece leaves the finishing mill, the sizing mill, pinch rolls, and wire spinner simultaneously begin to accelerate towards the target speed I according to the acceleration slope I.

[0081] 5) After the tail of the rolled piece leaves the reducing and sizing mill, as determined by HMD4, the reducing and sizing mill begins to decelerate. The pinch rolls begin to accelerate towards the target speed II according to the pinch roll acceleration slope II; at the same time, the compensation value of 100% of the rated torque output by the control system is directly superimposed on the torque setpoint of the frequency converter cabinet, and the spinning machine begins to accelerate towards the target speed II according to the spinning machine acceleration slope II.

[0082] 6) After the tail of the rolled piece leaves the spinning mill, the pinch rolls and the spinning mill will slow down and return to the normal rolling speed, as determined by HMD5.

[0083] According to the present invention, by using a tail speed optimization control method for large-diameter wires, the influence of tail speed on the finished coil shape is eliminated, thereby improving production stability and product quality, and increasing production efficiency. The effect is significant, for example... Figures 4-6 As shown, by using the optimized control method for the tail speed increase of large-diameter wire rods, the constraints of the mechanical capabilities of the reducing sizing mill, pinch rolls, and spinning machine on the production of ultra-large-diameter products have been reduced, saving subsequent modification costs. At the same time, the service life of the reducing sizing mill equipment has been extended, maintenance costs have been reduced, and significant economic benefits have been created.

Claims

1. A method for optimizing control of large-diameter wire rod tail speed increase, the wire rod diameter being φ15mm-φ30mm, and the wire rod high-speed process flow being: medium-large-diameter wire rod-HMD1-finishing mill-HMD2-HMD3-reducing sizing mill-HMD4-HMD5-pinch roll-wire rod forming machine, the tail tracking signal of the rolled piece starting from HMD1, the detector participating in the tracking of the tail of the rolled piece, and the tail speed increase method being adopted in the rolling control, characterized in that, if the reducing sizing mill outlet speed set value is lower than the tail speed increase function input speed threshold value one, the speed threshold value one being 22m / s, the tail speed increase function of the rolled piece is input, the reducing sizing mill, pinch roll and wire rod forming machine participate in the tail speed increase to realize the relay speed increase function of the reducing sizing mill, pinch roll and wire rod forming machine; the tail speed increase method includes the selection of two modes: if the rolled product specification is φ15mm-φ22mm, which is less than the specification threshold value two, the specification threshold value two being φ23mm, the first tail speed increase mode is selected, that is, only the pinch roll and wire rod forming machine participate in the tail speed increase, at this time, the reducing sizing mill acceleration slope I is set to zero, after the rolled piece tail leaves the wire rod forming machine, the pinch roll and wire rod forming machine are reduced in speed and restored to the normal rolling speed; if the rolled product specification is φ23mm-φ30mm, which is greater than or equal to the specification threshold value two, after the rolled piece tail leaves the wire rod forming machine, the pinch roll and wire rod forming machine are reduced in speed and restored to the normal rolling speed.

2. The method for optimizing control of large-diameter wire rod tail speed increase according to claim 1, characterized in that, an index table of tail speed increase related control parameters corresponding to the wire rod specification is established: in the control program, an index table of tail speed increase related control parameters corresponding to the wire rod specification is established, the related control parameters including: target speed I, which is the target speed at which the reducing sizing mill, pinch roll and wire rod forming machine simultaneously start to increase in speed from the designed product speed at an acceleration slope I after the tail of the rolled piece leaves the finishing mill, the speeds of the three being kept synchronous, if the target speed is reached before the tail leaves the reducing sizing mill, the target speed is maintained, target speed II, which is the target speed at which the pinch roll and wire rod forming machine start to increase in speed from the target speed I at an acceleration slope II after the tail of the rolled piece leaves the reducing sizing mill, if the target speed is reached before the tail reaches HMD5, the target speed is maintained, acceleration slope I, which is the acceleration slope at which the reducing sizing mill, pinch roll and wire rod forming machine start to increase in speed from the designed product speed towards the target speed I after the tail of the rolled piece leaves the finishing mill, pinch roll acceleration slope II, which is the acceleration slope at which the pinch roll starts to increase in speed from the target speed I towards the target speed II after the tail of the rolled piece leaves the reducing sizing mill, wire rod forming machine acceleration slope II, which is the acceleration slope at which the wire rod forming machine starts to increase in speed from the target speed I towards the target speed II after the tail of the rolled piece leaves the reducing sizing mill, the distance from the reducing sizing mill outlet to the wire rod forming machine being S; S=(target speed I+target speed II)×T / 2 target speed II=target speed I+acceleration slope II×T T: the time taken by the tail of the rolled piece to pass from the reducing sizing mill outlet to the wire rod forming machine. ​ ​ ​ ​ ​ ​ ​ The second tail speed-up mode is selected, that is, the reducing sizing machine, the pinch roll and the laying head participate in the tail speed-up simultaneously, at this time, the accelerating slope I of the reducing sizing machine is set to 0.5-1.1 m / s 2 , ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3. The method according to claim 1, wherein the first tail speed-up mode is selected, and wherein: target speed I is equal to the exit speed set value of the reducing mill, and the reducing mill does not participate in the speed-up; target speed II is 23-28 m / s; and acceleration slope I is 0.

4. The method according to claim 1, wherein the second tail speed-up mode is selected, and wherein: target speed I is 12-17 m / s; and target speed II is 23-28 m / s.

5. The method according to claim 4, wherein, after the workpiece tail exits the finishing mill, the reducing mill, the pinch roll, and the wire feeder simultaneously start to speed up according to the acceleration slope I toward the target speed I, as determined by the HMD2.

6. The method according to claim 5, wherein, after the workpiece tail exits the reducing mill, the reducing mill starts to slow down, the pinch roll starts to speed up according to the acceleration slope II toward the target speed II, and the wire feeder starts to speed up according to the acceleration slope II toward the target speed II, as determined by the HMD4, and wherein the compensation value of 100% rated torque output by the control system is directly superimposed on the torque set value of the frequency conversion cabinet, and the wire feeder starts to speed up according to the acceleration slope II toward the target speed II.

7. The method according to claim 4, wherein, after the workpiece tail exits the reducing mill, the reducing mill starts to slow down, the pinch roll starts to speed up according to the acceleration slope II toward the target speed II, and the wire feeder starts to speed up according to the acceleration slope II toward the target speed II. Pinch roll acceleration slope II is 5.5-9.5 m / s 2 , Spinning machine acceleration slope II is 5.5-9.5 m / s 2 .

8. The method according to claim 1, wherein the torque compensation of the wire feeder is used to improve the response of the wire feeder, the torque compensation value of the wire feeder is directly superimposed on the torque set value of the frequency conversion cabinet, the time of input is set to an adjustable advance, and the smooth transition of the coil shape of the two speed-up sections is achieved. ​ ​ ​ Acceleration slope I is 0.5-1.1 m / s 2 , Pinch roll acceleration slope II is 5.5-9.5 m / s 2 , Spinning machine acceleration slope II is 5.5-9.5 m / s 2 . ​ ​ ​ ​ ​ ​ ​ ​

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