A method for controlling the coil shape at the tail of large-diameter wire

Abstract

This invention relates to a method for controlling the tail coil shape of large-diameter wire rods, belonging to the technical field of high-speed wire rod production methods. The technical solution of this invention is as follows: during tail-end speed increase, the speed increase of the wire feeder and pinch rolls is changed from synchronous to asynchronous, with the wire feeder using a delayed speed increase; once the workpiece speed begins to stabilize, the wire feeder resumes synchronous speed increase; the air-cooled roller conveyor pauses operation during the last few coils, allowing the tail coils to concentrate at one position on the air-cooled roller conveyor; after the workpiece disengages from the pinch rolls and wire feeder, the pinch rolls and wire feeder resume normal speed, and the air-cooled roller conveyor resumes normal operation, preparing for the next wire feed. The beneficial effects of this invention are: achieving regular tail coil formation for large-diameter special steel wire rods, avoiding the impact on equipment caused by speed increase using a sizing and reducing unit; and the two flexibly adjustable parameters are applicable to adjusting the coil shape of products of various specifications, steel grades, and wire feed temperatures.

Description

Technical Field

[0001] This invention relates to a method for controlling the tail coil shape of large-diameter wire rods, belonging to the technical field of high-speed wire rod production methods. Background Technology

[0002] Typical advanced high-speed wire rod production lines cover product specifications from Φ5mm to Φ28mm. To ensure smooth wire ejection after the tail of the wire leaves the last stand mill, resulting in a standardized coil for subsequent collection and packaging, pinch rollers are installed in front of the wire ejector. When the tail of the wire loses forward momentum after leaving the last stand mill, the rotating pinch rollers hold the workpiece, causing the tail of the workpiece to move forward at a certain speed. At this time, the speed of the wire ejector automatically matches the speed, allowing the tail of the wire to smoothly eject a coil.

[0003] Since the wire rod's tail end relies entirely on inertia to form and exit the coil within the coiling tube after leaving the pinch rolls, a tail-end speed-up method is used for large-size products to increase the kinetic energy of the wire rod's tail end. This ensures that the tail end has sufficient inertia to form within the coiling tube and exit smoothly after leaving the pinch rolls. The tail-end speed-up is achieved by increasing the rotational speed of the workpiece held by the pinch rolls at the front of the coiling machine. During this process, the coiling machine and the pinch rolls increase their speeds synchronously to ensure that the coil shape remains unchanged.

[0004] For large-diameter special steel wire rods with diameters of Φ16mm-Φ28mm, due to their low wire-spinning temperature, low surface friction coefficient, and high alloy content, the deformation resistance formed in the wire-spinning tube at lower temperatures is large. In addition, due to their large weight, the friction between the rolled piece and the steel passage is large. The combined effect of these factors leads to a phenomenon where the actual wire speed is momentarily low in the initial stage of speed-up when relying solely on the pinch rolls to achieve tail-end acceleration. At this time, the linear speed of the rolled piece is lower than the linear speed of the wire-spinning machine, resulting in a small loop during wire spin-out, which adversely affects subsequent collection and packaging.

[0005] Another problem with large-diameter tail rings is that there are several loose rings at the tail. Due to the large diameter, the ring shape is fixed after cooling in the air-cooling line, and it is difficult to straighten them again in subsequent collection and packaging, resulting in the tail rings being distributed in a fan shape, which affects the packaging quality.

[0006] Patents CN 117299787 A and CN 103372565 B disclose an optimized control method for the tail speed increase of large-diameter wire rods, which solves this problem by simultaneously increasing the speed of the pinch rollers and the reducing and sizing machine. However, this method causes the tail speed of the reducing and sizing machine to rapidly increase and decrease once for each wire rod, which adversely affects the lifespan of the motor, gears, and bearings, and does not provide a solution for tail-end wheel slippage. Summary of the Invention

[0007] The purpose of this invention is to provide a method for controlling the tail coil shape of large-diameter wire rods. By changing the synchronous speed increase of the original wire drawing machine and pinch rollers to asynchronous speed increase, the problem of small coils is solved. The problem of loose coils at the tail is solved by pausing the air-cooled roller conveyor at the tail of the wire drawing. This achieves regular tail coil formation for large-diameter special steel wire rods, avoiding the impact on the equipment caused by speed increase of the sizing unit. The two flexibly adjustable parameters can be used to adjust the coil shape of products of various specifications, steel grades, and wire drawing temperatures, effectively solving the above-mentioned problems existing in the background technology.

[0008] The technical solution of this invention is: a method for controlling the coil shape at the tail of large-diameter wires, comprising the following steps:

[0009] Step S1: When accelerating at the tail end, the speed control of the spinning machine and the pinch roller is changed from synchronous speed control to asynchronous speed control, and the spinning machine adopts delayed speed control.

[0010] Step S2: When the speed of the rolled piece begins to rise steadily, the wire spinning machine will then increase its speed synchronously.

[0011] Step S3: The air-cooled roller conveyor pauses operation during the last few turns of yarn feeding, causing the tail coils to fall into one position on the air-cooled roller conveyor.

[0012] Step S4: After the rolled piece leaves the pinch rolls and the wire feeder, the pinch rolls and the wire feeder return to normal speed, the air-cooled roller conveyor returns to normal operation, and the next steel wire is prepared for feeding.

[0013] Add a speed-up delay adjustment window for the spinning machine to the speed-up control program for the spinning machine and pinch rolls. The adjustment range of the delay adjustment window is 0-1000 milliseconds.

[0014] The speed delay setting of the spinneret speed-up delay adjustment window is matched with the coil pattern produced by the spinneret in the initial stage of the pinch roller speed-up.

[0015] In step S3, a No. 2 hot metal detector is installed 16-20 meters in front of the spinning machine. When the tail of the rolled piece reaches this position, the hot metal detector sends a signal. After the delay length set by the delay adjustment window, the air-cooled roller conveyor stops running, so that the tail coils spun out by the spinning machine are concentrated in one position on the roller conveyor, thus avoiding the formation of scattered coils.

[0016] The delay length set in the delay adjustment window is matched with the number of coil turns that need to be concentrated.

[0017] In step S4, a No. 3 hot metal detector is installed in front of the wire spinning machine to detect the position of the tail of the rolled piece.

[0018] The beneficial effects of this invention are: by changing the original synchronous speed increase of the wire drawing machine and pinch roller to asynchronous speed increase, the problem of small coils is solved; by pausing the air-cooled roller conveyor at the tail of the wire drawing, the problem of scattered coils at the tail is solved; thus, the tail coils of large-specification special steel wires are formed in a regular manner, avoiding the impact on the equipment caused by using a diameter measurement unit for speed increase; and the two flexibly adjustable parameters can be used to adjust the coil shape of products of various specifications, steel grades, and wire drawing temperatures. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is a real-world image of the tail loop shape in the background technology.

[0021] Figure 3 This is a physical image of the tail ring shape of the present invention;

[0022] In the diagram: 1# hot metal detector, 2# hot metal detector, 3# hot metal detector, 4# reducing and sizing machine, 5# water tank, 6# pinch roll and spinning machine, 7# air-cooled roller conveyor. Detailed Implementation

[0023] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0024] A method for controlling the coil shape at the tail of large-diameter wires includes the following steps:

[0025] Step S1: When accelerating at the tail end, the speed control of the spinning machine and the pinch roller is changed from synchronous speed control to asynchronous speed control, and the spinning machine adopts delayed speed control.

[0026] Step S2: When the speed of the rolled piece begins to rise steadily, the wire spinning machine will then increase its speed synchronously.

[0027] Step S3: The air-cooled roller conveyor pauses operation during the last few turns of yarn feeding, causing the tail coils to fall into one position on the air-cooled roller conveyor.

[0028] Step S4: After the rolled piece leaves the pinch rolls and the wire feeder, the pinch rolls and the wire feeder return to normal speed, the air-cooled roller conveyor returns to normal operation, and the next steel wire is prepared for feeding.

[0029] Add a speed-up delay adjustment window for the spinning machine to the speed-up control program for the spinning machine and pinch rolls. The adjustment range of the delay adjustment window is 0-1000 milliseconds.

[0030] The speed delay setting of the spinneret speed-up delay adjustment window is matched with the coil pattern produced by the spinneret in the initial stage of the pinch roller speed-up.

[0031] In step S3, a No. 2 hot metal detector is installed 16-20 meters in front of the spinning machine. When the tail of the rolled piece reaches this position, the hot metal detector sends a signal. After the delay length set by the delay adjustment window, the air-cooled roller conveyor stops running, so that the tail coils spun out by the spinning machine are concentrated in one position on the roller conveyor, thus avoiding the formation of scattered coils.

[0032] The delay length set in the delay adjustment window is matched with the number of coil turns that need to be concentrated.

[0033] In step S4, a No. 3 hot metal detector is installed in front of the wire spinning machine to detect the position of the tail of the rolled piece.

[0034] In practical applications, a speed-up delay adjustment window for the spinning machine is added to the speed-up control program of the spinning machine and the pinch roller. The time adjustment range is 0-1000 milliseconds, and this time is defined as T1.

[0035] Install a No. 2 hot metal detector 16-20 meters in front of the spinning machine. When the tail of the rolled piece reaches this position, the hot metal detector sends a signal. After a delay of T2, the air-cooled roller conveyor stops running, so that the last 3-5 coils of the spinning machine are concentrated in one position on the roller conveyor, avoiding the formation of scattered coils.

[0036] By adjusting the delay length, the number of wire turns that fall in the final concentrated phase can be accurately controlled. The delay length T2 is automatically calculated by the control system based on the required number of coil turns, and the calculation method is as follows:

[0037] The diameter of the spinning spool is 1020mm. The length of wire for one round of spinning is 3.14 * 1.02 = 3.2 (meters).

[0038] If we want the last N turns of wire to fall together and be collected on the air-cooled roller conveyor, then the total length L of the wire is: L = 3.2 * N (meters)

[0039] Assuming the distance between the #2 heat detector and the spinning machine is 16 meters, then T2 = (16 - L) / V (seconds)

[0040] V is the linear speed of the pinch roller (m / s).

[0041] A No. 3 hot metal detector is installed in front of the wire drawing machine to detect the position of the tail of the rolled piece. When the tail is removed from the wire drawing machine, the pinch roll and the wire drawing machine return to their initial speed, and the air-cooled roller conveyor returns to normal speed operation, ready to roll the next steel. Example

[0042] Taking Φ22mm bearing steel wire as an example, combined with Figure 1 This section explains the specific implementation methods.

[0043] The normal rolling speed for this specification of wire is 12 m / s, accelerating to 28 m / s at the tail end to ensure smooth wire output. During normal rolling, the exit speed of the sizing mill is 12 m / s, the idle speed of the wire feed rolls is 12.6 m / s (speed lead rate 5%), and the wire feed roll linear speed is 13.2 m / s (speed lead rate 10%).

[0044] Install a No. 1 hot metal detector 1-5 meters in front of the reducing and sizing machine, a No. 2 hot metal detector 16 meters away from the pinch roll, and a No. 3 hot metal detector in front of the pinch roll of the spinning machine.

[0045] When the No. 1 hot metal detector changes from a state with steel to a state without steel, the pinch rollers begin to increase speed according to the set slope.

[0046] Set the speed-up delay window of the spinning machine to 100 milliseconds. Observe the shape of the spinning machine's output rings in the initial stage of the pinch roller speed-up. If it is too small, increase the delay window to 200 milliseconds. If it is too large, decrease the delay to 50 milliseconds.

[0047] Repeat the above process until a suitable delay value is set so that there are no small or large loops during the entire process of the pinch roller speeding up.

[0048] When the signal of the #3 hot metal detector changes from steel to no steel, it indicates that the workpiece has completely passed through the pinch rolls. The pinch rolls then return to their initial speed before acceleration, ready to roll the next piece of steel.

[0049] If it is desired that the tail of the wire has 4 loops concentrated on the roller conveyor, then:

[0050] The length of the 4 coils of wire is: 4 * 3.2 = 12.8 meters.

[0051] When the air-cooled roller conveyor begins to pause, the distance from the tail of the wire to the #2 hot metal detector is:

[0052] 16 - 12.8 = 3.2 (meters)

[0053] The wire speed is 28 m / s at this time. The time from when the No. 2 hot metal detector detects no steel to when the roller conveyor starts to pause is: 3.2 / 28=0.114 (seconds).

[0054] That is: after the No. 2 hot metal detector detects no steel, the roller conveyor will pause after 0.114 seconds, and will continue until the No. 3 hot metal detector detects no steel and the roller conveyor will resume moving forward.

[0055] Using the above methods, the number of laps with concentrated tail fall can be flexibly adjusted within the range of 0-5 laps.

[0056] When the No. 3 hot metal detector detects no steel and the tail of the wire has completely detached from the wire feeder, the pinch rollers and wire feeder return to their initial speeds of 12.6 m / s and 13.2 m / s, respectively. The air-cooled roller conveyor resumes normal operation, ready to feed the head of the next steel wire.

Claims

1. A method for controlling the coil shape at the tail of large-diameter wires, characterized in that... Includes the following steps: Step S1: When the speed is increased at the tail end, the speed increase of the spinning machine and the pinch roll is changed from synchronous speed increase to asynchronous speed increase control, and the spinning machine adopts delayed speed increase; a No. 1 hot metal detector is installed 1-5 meters in front of the reducing and sizing machine. When the No. 1 hot metal detector changes from the state with steel to the state without steel, the pinch roll starts to increase speed according to the set slope. Step S2: When the speed of the rolled piece begins to rise steadily, the spinning machine will then increase its speed synchronously; add a spinning machine speed-up delay adjustment window to the spinning machine and pinch roll speed-up control program, with the adjustment range of the delay adjustment window being 0-1000 milliseconds; Step S3: The air-cooled roller conveyor pauses operation during the last few turns of yarn feeding, causing the tail coils to fall into one position on the air-cooled roller conveyor. Step S4: After the rolled piece leaves the pinch rolls and the wire feeder, the pinch rolls and the wire feeder return to normal speed, the air-cooled roller conveyor returns to normal operation, and the next steel wire is prepared for feeding.

2. The method for controlling the coil shape at the tail of a large-diameter wire according to claim 1, characterized in that: The speed delay setting of the spinneret speed-up delay adjustment window is matched with the coil pattern produced by the spinneret in the initial stage of the pinch roller speed-up.

3. The method for controlling the tail coil shape of large-diameter wire according to claim 1, characterized in that: In step S3, a No. 2 hot metal detector is installed 16-20 meters in front of the spinning machine. When the tail of the rolled piece reaches this position, the hot metal detector sends a signal. After the delay length set by the delay adjustment window, the air-cooled roller conveyor stops running, so that the tail coils spun out by the spinning machine are concentrated in one position on the roller conveyor, thus avoiding the formation of scattered coils.

4. The method for controlling the tail coil shape of large-diameter wire according to claim 3, characterized in that: The delay length set in the delay adjustment window is matched with the number of coil turns that need to be concentrated.

5. The method for controlling the tail coil shape of large-diameter wires according to claim 1, characterized in that: In step S4, a No. 3 hot metal detector is installed in front of the wire spinning machine to detect the position of the tail of the rolled piece.

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