A control method for tail deviation in the entrance section of a cold rolling continuous annealing unit

Abstract

The invention discloses a control method for tail swinging and deviation in the entrance section of a cold rolling continuous annealing unit, and belongs to the field of metallurgical equipment. It includes the following steps: 1. Install a pinch roller after shearing between a double-layer shear and a welder, and install a pressure roller between the pinch roller after shearing and the welder near the welder; 2. When the strip enters the tail swinging stage, reduce the moving speed of the strip to a first set speed and make the strip tail not fall off the coiler. At this time, control the pinch roller after shearing and the pressure roller to press down, and then continue to reduce the moving speed of the strip tail to stop, and the double-layer shear works to cut the strip; 3. After cutting the strip, make the pinch roller after shearing and the pressure roller continue to be in a pressed down state, control the strip to move to the front of the welder at a second set speed and stop, enter the welding state, and the strip tail swinging ends. During the movement, control the driving motor of the pinch roller after shearing to be in a negative torque operation state. The invention can effectively solve the strip deviation phenomenon in the entrance section and improve the production efficiency of the production line.

Description

Technical Field

[0001] The invention belongs to the field of metallurgical equipment, and more specifically, relates to a method for controlling tail swinging and deviation in an entrance section of a cold rolling continuous annealing unit. Background Art

[0002] In the cold rolling post-processing continuous production line, the cold rolled strip will be coiled to the product coil off the line through the coiler after continuous annealing and coating. Among them, the main equipment in the entrance section of the cold rolling continuous annealing unit includes the uncoiler, double-layer shear, welder, tension roller and entrance looper. The uncoiler is responsible for the uncoiling of the steel coil, the double-layer shear is responsible for the strip slitting and the head and tail scrap cutting, the welder is responsible for the welding of the strip tail and the strip head, the tension roller is responsible for the tension establishment and operation of the entrance section and the entrance looper, and the entrance looper is for the continuous operation of the central section to store the strip when the steel coil is replaced in the entrance section. The main process operations include coiling, cutting the head, the strip head to the waiting position, the strip head to the welding machine, welding, tensioning operation, tail swinging, parking, cutting the tail, and the strip tail to the welding machine. Among them, tail swinging plays a vital role in the continuous operation of the unit.

[0003] At present, the tail-swinging process of the entrance section is generally to calculate the coil diameter of the steel coil on the unwinder to obtain the remaining coil diameter of the strip. When the remaining coil diameter of the strip is less than the set value, the entrance section will reduce the speed from the unwinding speed to a low speed and run at a low speed for the set tail-swinging time, then stop and cut, cut the unqualified tail into pieces and send them to waste, and complete the tail-swinging work.

[0004] However, when entering tail swing control, after the double-layer shear cuts the strip and the strip tail detaches from the unwinder, the strip tail will lose tension control. In this case, when the strip tail runs to the welding machine to be welded with the next roll of strip, the strip tail may deviate due to other factors such as the plate shape (usually the strip tail plate shape is relatively poor) and the channel roller system. In particular, for the entrance section of the existing double unwinding structure, the length of the strip tail after the upper channel is cut is longer than that of the lower channel and there is also a ramp, which makes the tail swing more frequent, directly affecting the normal centering function of the welding machine. In severe cases, it may even cause the strip tail to scrape the edge, resulting in the unit shutdown. Since this deviation is random and the deviation direction occurs on both the transmission side and the operating side, handling it will bring certain safety risks, which has a great impact on the continuous production of cold-rolled strip.

[0005] The Chinese patent application number is: CN201110429942.8, and the patent document with the publication date of June 13, 2012 discloses a control method for high-speed tail swinging of a cold rolling processing line uncoiler, which is characterized in that when the remaining strip length COIL on the uncoiler is less than a certain set value, a tail deceleration positioning process is started. After the deceleration positioning starts, the remaining strip length COIL on the uncoiler is continuously detected, and the positioning set value SETP is adjusted in real time. The positioning remaining distance POS is also continuously adjusted, wherein POS is equal to SETP-DIS, and the positioning remaining distance POS corresponds to the positioning speed Vpos. When POS gradually decreases to zero, Vpos will also gradually decrease to zero. Therefore, when the positioning remaining distance POS becomes zero, the unit stops and the tail is cut. At this point, the high-speed tail swinging of the cold rolling processing line uncoiler is completed.

[0006] The Chinese patent application number is CN201910994153.5, and the patent document with the publication date of January 31, 2020 discloses a fully automatic tail swinging control method and system for a cold rolling annealing unit, wherein the method is as follows: when the remaining strip length is less than the first preset length, a first control signal is output to reduce the strip speed from the unwinding speed to the first operating speed; when the strip tension between the unwinder and the tension roller drops to zero, a second control signal is output to reduce the strip speed from the first operating speed to the second operating speed; the remaining length of the strip tail is obtained, and the remaining length of the strip tail is the difference between the first positioning length and the positioning moving length; wherein the first positioning length is the sum of the distance from the shearing point to the unwinder when the strip tension drops to zero and the circumference of the unwinder mandrel; the positioning moving length is the distance from the moment when the strip tension drops to zero to the moment of acquisition when the strip moves at the second operating speed; when the remaining length of the strip tail is less than the second preset length, a third control signal is output to stop the unit and shear the strip tail.

[0007] The methods in the above two schemes are both control methods for the strip steel entering the tail swinging stage at the entrance section of the cold rolling continuous annealing unit, but neither of them involves treatment measures for the strip steel tail swinging and deviation, and cannot solve the problem of strip steel deviation in the tail swinging stage mentioned above. The current method for controlling the deviation of the strip steel at the entrance section is generally to manually push and pull the deviated strip steel or adjust the relevant parameters of the tension roller, the entrance looper, and the welding machine, but the adjustment effect of the strip steel deviation is often not good. Summary of the invention

[0008] 1. Problems to be solved

[0009] In view of the fact that the prior art is unable to ideally solve the problem that the strip steel enters the tail swinging stage at the entrance section of a cold rolling continuous annealing unit and deviates, the present invention provides a method for controlling the tail swinging deviation at the entrance section of a cold rolling continuous annealing unit, which can effectively solve the strip steel deviation phenomenon at the entrance section and improve the production efficiency of the production line.

[0010] 2. Technical solution

[0011] To solve the above problems, the present invention adopts the following technical solutions.

[0012] A method for controlling tail swinging and deviation in an entrance section of a cold rolling continuous annealing unit comprises the following steps:

[0013] 1. Install the pinch roller after shearing between the double-layer shearing machine and the welding machine, and install the pressure roller between the pinch roller after shearing and the welding machine near the welding machine;

[0014] Second, when the strip enters the tail swinging stage, the strip moving speed is reduced to the first set speed and the strip tail does not fall off the coiler. At this time, the pinch roller and the pressure roller after the shear are controlled to press down, and then the strip tail moving speed is further reduced until it stops, and the double-layer shear works to cut the strip;

[0015] 3. After the strip is cut, the pinch roller and the pressure roller after cutting are kept in the downward state, and the strip is controlled to move to the front of the welding machine at the second set speed and stop, entering the welding state, and the strip tail is finished. During the movement, the drive motor of the pinch roller after cutting is controlled to be in the negative torque operation state.

[0016] As a further improvement of the technical solution, in the step one, a pre-shear pinch roller is installed between the uncoiler and the double-layer shear; in the step two, the pre-shear pinch roller and the post-shear pinch roller are kept pressed down synchronously.

[0017] As a further improvement of the technical solution, the first set speed is 50-70 m / min.

[0018] As a further improvement of the technical solution, the second set speed is 25-35m / min.

[0019] As a further improvement of the technical solution, the set value of the negative torque is calculated using the following formula:

[0020] T = T1 + (W1*H1) / (W0*H*)*A;

[0021] Among them, T is the negative torque setting value, T1 is the strip tension, W1 is the strip width, H1 is the strip thickness, W0 is the minimum strip width, H0 is the minimum strip thickness, and A is the conversion coefficient.

[0022] As a further improvement of the technical solution, when a double decoiler is used, the post-cutting pinch rollers include a steering pinch roller installed on the upper channel and a common pinch roller acting on the two channels.

[0023] As a further improvement of the technical solution, in step 2, when the strip starts to slow down, the remaining length of the strip on the uncoiler is S, and S is calculated using the following formula:

[0024] S = S1 + S2 + S3;

[0025] V = (V1-V2) / 2;

[0026] T = (V1-V2) / VΔ;

[0027] S1=V*T;

[0028] Among them, S1 is the running distance of the strip when the strip drops from the current moving speed to the first set speed, S2 is the distance between the uncoiler and the double-layer shear, and S3 is the offset compensation amount; V is the average speed, V1 is the current moving speed of the strip, and V2 is the first set speed; T is the deceleration time, and VΔ is the deceleration rate.

[0029] As a further improvement of the technical solution, the distance between the uncoiler and the double-layer shear is 10-15m, and the offset compensation amount is 3-5m.

[0030] As a further improvement of the technical solution, the current moving speed of the strip is 100-300 m / min, and the deceleration rate is 0.5-0.6 m / s 2 .

[0031] As a further improvement of the technical solution, in step 2, the pressure of the pinch roller and the pressure roller is controlled by a cylinder, and the cylinder pressure value on the strip is 0.4-0.5MPa.

[0032] 3. Beneficial effects

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention discloses a method for controlling tail swinging and deviation at an entrance section of a cold rolling continuous annealing unit. By improving the structure of the entrance section of the existing cold rolling continuous annealing unit and coordinating with a corresponding control method, the added pinch rollers and pressure rollers are controlled to press down the strip, so that the strip can be in a state of certain tension as much as possible during the tail swinging stage, and the moving distance of the strip when the tension is lost is reduced, thereby effectively controlling the strip from running and improving production efficiency. In particular, the present invention has carried out unique parameter design for the operation of various equipment at the entire entrance end during the tail swinging stage, and the movement process of the strip is controlled extremely accurately, which greatly reduces the probability of the strip from running. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the inlet section of the cold rolling continuous annealing unit;

[0036] In the figure: 1. First uncoiler; 2. Second uncoiler; 3. First uncoiler pinch roller; 4. Second uncoiler pinch roller; 5. Pre-shear pinch roller; 6. Double-layer shear; 7. Steering pinch roller; 8. Common pinch roller; 9. Support roller; 10. Press roller; 11. Welding machine; 12. Tensioning roller; 13. Tensioning roller and press roller. DETAILED DESCRIPTION

[0037] Exemplary embodiments of the present invention are described in detail below. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments may be implemented and various changes may be made to the present invention without departing from the spirit and scope of the present invention. The more detailed description of the embodiments of the present invention below is not intended to limit the scope of the claimed invention, but is merely for illustration and does not limit the description of the features and characteristics of the present invention, in order to propose the best mode for performing the present invention, and is sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0038] Example

[0039] A method for controlling tail deviation in the entrance section of a cold rolling continuous annealing unit is applicable to the cold rolling continuous production line, and is applicable to the entrance section of the annealing unit and the entrance section of the galvanizing unit in the cold rolling production line, and is particularly applicable to an entrance section structure that adopts a double uncoiler and is divided into two upper and lower uncoiler channels. The specific contents are described in detail below.

[0040] like Figure 1 As shown, the entrance section structure includes a first decoiler 1 and a second decoiler 2 arranged adjacent to each other. After the strip comes out of the two decoilers, it moves in two upper and lower decoiler channels. The strip passes through the double-layer shear 6, the roller 9, the welder 11 and the tensioning roller 12 in sequence and then enters the entrance loop.

[0041] In order to enable the strip to smoothly move along the channel and enter the double-layer shear 6 after coming out of the uncoiler, the first uncoiler pinch roller 3 and the second uncoiler pinch roller 4 are respectively installed at the exits of the first uncoiler 1 and the second uncoiler 2, and a pre-shear pinch roller 5 is installed before the double-layer shear 6. The first uncoiler pinch roller 3 guides the strip of the upper channel coming out of the first uncoiler 1 to the corresponding position of the pre-shear pinch roller 5, and the pre-shear pinch roller 5 guides the strip of the upper channel to the double-layer shear 6, and the second uncoiler pinch roller 4 directly guides the strip of the lower channel coming out of the second uncoiler 2 to the double-layer shear 6.

[0042] Steering pinch roller 7 and common pinch roller 8 are installed between double-layer shear 6 and supporting roller 9, wherein steering pinch roller 7 controls the moving direction of the strip steel in the upper channel to move downward so as to enter common pinch roller 8, and common pinch roller 8 delivers the strip steel in the upper and lower channels to the next device. Pressure roller 10 is installed in front of welding machine 11, and pressure roller 10 is controlled by cylinder, which can press down to apply certain pressure to the strip steel, so that the strip steel maintains tension and moves stably. At the same time, tension roller 12 is provided with tension roller 13, which plays the same role as pressure roller 10.

[0043] This embodiment improves the structure of the entrance section of the cold rolling continuous annealing unit so that the moving direction of the strip thereon is accurate and the overall operation is relatively stable. At the same time, these improvements, combined with a unique control method, also solve the problem of the strip running off the track during the tail swinging stage. The specific control method includes the following steps.

[0044] 1. Improvements are made on the basis of the original entrance section of the cold rolling continuous annealing unit to form a unique entrance section structure in this embodiment. Specifically, the first unwinding pinch roller 3 and the second unwinding pinch roller 4 are installed at the exits of the first unwinding machine 1 and the second unwinding machine 2, respectively, and the pre-shear pinch roller 5 is installed in front of the double-layer shear 6. The post-shear pinch roller is installed between the double-layer shear 6 and the welder, and the post-shear pinch roller includes a steering pinch roller 7 and a common pinch roller 8. At the same time, a pressure roller 10 and a tension roller pressure roller 13 are installed in front of the welder 11 and at the tension roller 12, respectively.

[0045] 2. During the production process of the cold rolling continuous annealing unit, when the strip at the inlet section enters the tail swinging stage, the strip moving speed begins to decrease, and when the strip moving speed decreases to the first set speed, it is necessary to ensure that the strip tail does not fall off the coiler. The first set speed is generally selected within the range of 50-70m / min according to actual conditions, and is 60m / min in this embodiment.

[0046] Next, the first unwinding pinch roller 3, the pre-cutting pinch roller 5, the steering pinch roller 7, the common pinch roller 8, the pressure roller 10 and the tension roller 13 are controlled to be pressed down at the same time to apply a certain pressure to the strip. In this embodiment, each roller is driven by the cylinder installed thereon to press down to control the pressure applied to the surface of the strip. The specific installation method of the cylinder belongs to the existing pressure roller structure that should be known to those skilled in the art, and will not be described in detail here. The cylinder pressure is generally selected in 0.4-0.5MPa, and in this embodiment it is 0.45MPa.

[0047] Next, the moving speed of the strip tail is further reduced until it stops, and the double-layer shear 6 works to cut the strip steel.

[0048] In order to accurately control the overall operation of the strip, it is necessary to accurately control the speed reduction point of the strip. This embodiment adopts the following control method.

[0049] When the remaining length of the strip on the uncoiler is detected to be S, when the strip starts to slow down, the remaining length of the strip on the uncoiler is S. When S is detected, the following formula is used for calculation:

[0050] S = S1 + S2 + S3;

[0051] V = (V1-V2) / 2;

[0052] T = (V1-V2) / VΔ;

[0053] S1=V*T;

[0054] Among them, S1 is the running distance of the strip when the current moving speed of the strip is reduced to the first set speed. S2 is the distance between the uncoiler and the double-layer shear, which is generally 10-15m. S3 is the offset compensation amount, which is generally 3-5m. V is the average speed. V1 is the current moving speed of the strip, which is generally 100-300m / s. V2 is the first set speed, which is generally 50-70m / min. T is the deceleration time, and VΔ is the deceleration rate, which is generally 0.5-0.6m / s 2 .

[0055] 3. After the strip is cut, the pinch roller and the pressure roller are kept in the downward state, and the strip is controlled to move to the front of the welding machine at the second set speed and stop, and enter the welding state. The strip tail is finished. During the movement, the drive motor of the pinch roller is controlled to be in the negative torque operation state. The second set speed is generally 25-35m / min, and in this embodiment it is 30m / min. The set value of the negative torque is calculated using the following formula:

[0056] T = T1 + (W1*H1) / (W0*H*)*A;

[0057] Among them, T is the negative torque setting value, T1 is the current tension of the strip, W1 is the strip width, H1 is the strip thickness, W0 is the minimum width of the strip in all positions on the production line, H0 is the minimum thickness of the strip in all positions on the production line, and A is the conversion coefficient, which is determined according to the actual production conditions. It should be noted that the unit of T is N·m, the unit of T1 is N, the unit of the width and thickness of the strip is m, and the formula is the conversion of the value before the unit when calculating, without considering the consistency of the units on both sides.

[0058] In the above manner, before the double-layer shear 6 stops to cut the strip, each position of the strip can be pressed and subjected to appropriate pressure, so that the strip itself has a certain tension during the movement process, avoiding the strip from running off. In particular, the pressure roller 10 is arranged in front of the welding machine 11, so that after the strip is cut, the strip is only in a state of losing tension during the distance from the tail of the strip leaving the pressure roller 10 and moving to the front of the welding machine 11, and this distance is generally not more than 1m, thereby minimizing the tension-free running length of the strip during the tail swinging process, and achieving tail swinging without running off.

[0059] In summary, the method for controlling tail deviation in the entrance section of a cold rolling continuous annealing unit in this embodiment can effectively solve the strip deviation phenomenon in the entrance section and improve the production efficiency of the production line.

[0060] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A method for controlling tail swinging at the entrance section of a cold rolling continuous annealing unit, characterized in that: The following steps are involved:

1. Install the pinch roller after shearing between the double-layer shearing machine and the welding machine, and install the pressure roller between the pinch roller after shearing and the welding machine near the welding machine; Second, when the strip enters the tail swinging stage, the strip moving speed is reduced to the first set speed and the strip tail does not fall off the coiler. At this time, the pinch roller and the pressure roller after the shear are controlled to press down, and then the strip tail moving speed is further reduced until it stops, and the double-layer shear works to cut the strip; 3. After the strip is cut, the pinch roller and the pressure roller after cutting are kept in the downward state, and the strip is controlled to move to the front of the welding machine at the second set speed and stop, and enter the welding state. The strip tail is finished, and during the movement, the driving motor of the pinch roller after cutting is controlled to be in the negative torque operation state; In the step 1, a pre-shear pinch roller is installed between the uncoiler and the double-layer shear; in the step 2, the pre-shear pinch roller and the post-shear pinch roller are pressed down synchronously; The first set speed is 50-70m / min; The second set speed is 25-35m / min; The set value of the negative torque is calculated using the following formula: T = T1 + (W1*H1) / (W0*H*)*A; Among them, T is the negative torque setting value, T1 is the strip tension, W1 is the strip width, H1 is the strip thickness, W0 is the minimum strip width, H0 is the minimum strip thickness, and A is the conversion coefficient; In the step 2, when the strip starts to slow down, the remaining length of the strip on the uncoiler is S, and S is calculated using the following formula: S = S1 + S2 + S3; V = (V1-V2) / 2; T = (V1-V2) / VΔ; S1=V*T; Among them, S1 is the running distance of the strip when the strip drops from the current moving speed to the first set speed, S2 is the distance between the uncoiler and the double-layer shear, and S3 is the offset compensation amount; V is the average speed, V1 is the current moving speed of the strip, and V2 is the first set speed; T is the deceleration time, and VΔ is the deceleration rate.

2. The method for controlling tail swinging at the entrance section of a cold rolling continuous annealing unit according to claim 1, characterized in that: When a double decoiler is used, the post-cutting pinch rollers include a deflecting pinch roller installed on the upper channel and a common pinch roller acting on the two channels.

3. The method for controlling tail deviation at the entrance section of a cold rolling continuous annealing unit according to claim 1, characterized in that: The distance between the uncoiler and the double-layer shear is 10-15m, and the offset compensation amount is 3-5m.

4. The method for controlling tail swinging at the entrance section of a cold rolling continuous annealing unit according to claim 1, characterized in that: The current moving speed of the strip is 100-300 m / min, and the deceleration rate is 0.5-0.6 m / s 2 .

5. A method for controlling tail swinging at the entrance section of a cold rolling continuous annealing unit according to claim 4, characterized in that: In the step 2, the pinch roller and the pressure roller are pressed down by the cylinder, and the cylinder pressure value is 0.4-0.5MPa for the strip steel.

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