A method for realizing strip recoiling in cold rolling skin-pass mill

Abstract

The present invention discloses a method for recoiling steel strips on a cold-rolling skin-pass mill. The method comprises controlling the cold-rolling skin-pass mill to enter a recoiling mode. In the recoiling mode, the cold-rolling skin-pass mill is controlled to throw off a given speed master command and send the given speed master command to a coiler, thereby releasing the tension control of the coiler. In the upper threading mode, tension is established on the uncoiler, while the coiler maintains static tension. In the lower threading mode, tension is established on the uncoiler, the inlet tension roller, and the outlet tension roller, while the coiler maintains static tension. The upper working roll of the cold-rolling skin-pass mill is withdrawn, while the lower working roll of the cold-rolling skin-pass mill is retained. After the steel strip is threaded, the lower working roll is lowered to the lowest position. The present invention uses the coiler as the speed control master signal to achieve the recoiling function of the entire line, thereby revitalizing the production capacity of the skin-pass mill unit and eliminating the need for cumbersome roll-changing mode operations, thereby greatly improving the production rhythm of the entire cold rolling mill.

Description

Technical Field

[0001] The invention belongs to the technical field of strip steel processing, and in particular relates to a method for realizing strip steel recoiling by a cold rolling skin pass mill. Background Art

[0002] Strip steel is a narrow and long steel plate produced by various steel rolling companies to meet the needs of industrial production of various metal or mechanical products.

[0003] Currently, existing skin-pass mills are primarily used to produce annealed strip and lack recoiling capabilities. The mismatch between the designed capacity of the skin-pass line and the recoiling line in the cold rolling process prevents the skin-pass mill from fully utilizing its capacity, resulting in wasted production capacity. Furthermore, some coils from the associated continuous rolling line, pickling line, and 18-high mill require recoiling and slitting, requiring only recoiling on the recoiling line. This hinders the unused capacity of the finishing mill.

[0004] In summary, the existing cold rolling process layout could no longer meet production needs, hindering production pace. This also resulted in limited output from the skin-pass mill, and the rewinding line was unable to maximize its capacity due to the high volume of repaired coils. A technical solution for rewinding strip on a cold skin-pass mill was urgently needed. Summary of the Invention

[0005] To this end, the present invention provides a method for a cold rolling and tempering mill to achieve strip recoiling, thereby solving the problem that traditional cold rolling and tempering mills cannot fully utilize their production capacity, resulting in waste of production capacity.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a method for recoiling a steel strip in a cold rolling and skin-pass mill, comprising:

[0007] Controlling the cold rolling and tempering mill to enter a rewinding mode. In the rewinding mode, the cold rolling and tempering mill is controlled to throw off the speed master command, send the speed master command to the coiler, and release the tension control of the coiler;

[0008] In the upper threading mode, the uncoiler tension is established and the coiler maintains static tension; in the lower threading mode, the uncoiler / entry tension roller / exit tension roller establish tension and the coiler maintains static tension.

[0009] The upper working roll of the cold rolling mill is withdrawn, and the lower working roll of the cold rolling mill is retained. After the steel strip is threaded, the lower working roll is lowered to the lowest position.

[0010] As a preferred solution for the method of realizing strip recoiling on the cold rolling mill, in the recoiling mode, the coiler enters the speed control state, and the strip tension on the cold rolling mill changes from four tension levels to three tension levels:

[0011] The tension in the down-threading mode is T1 generated at the uncoiler, T2 at the entrance tension roller, and T3 at the exit tension roller. The total tension of the cold rolling mill production line is: T1+T2+T3.

[0012] As a preferred method for realizing strip recoiling by a cold rolling mill, the tension T1 generated by the uncoiler is set by multiplying the continuous rolling coiling tension by an empirical coefficient, and the empirical coefficient is set to a value of 0.8 to 1.0.

[0013] As a preferred solution for the method of realizing strip recoiling in a cold rolling skin-pass mill, the tension T2 generated by the entrance tension roller is preset to 1.0 to 1.2 times that before the recoiling mode;

[0014] The tension T3 generated by the outlet tension roller is preset to be 1.0 to 1.2 times the tension before the rewinding mode.

[0015] As a preferred solution for the method of realizing strip recoiling in the cold rolling mill, after the lower working roll is lowered to the lowest position, the recoiling mode is not switched to the roll changing mode and the upper working roll is directly withdrawn.

[0016] As a preferred solution for the method of realizing strip recoiling by the cold rolling mill, in the recoiling mode, the height of the entrance anti-wrinkle roller is adjusted to a specified position before the cold rolling mill is accelerated.

[0017] As a preferred solution for the method of implementing strip recoiling in a cold rolling skin-pass mill, in the recoiling mode:

[0018] Disconnect the main drive operation chain of the cold rolling mill;

[0019] Throw away the lubrication control system of the cold-rolling skin-pass mill;

[0020] Shield the motor operation signal interlock of the cold rolling mill.

[0021] As a preferred solution for the method of implementing strip recoiling in a cold rolling skin-pass mill, in the recoiling mode:

[0022] Adjust the parking logic in rewind mode;

[0023] The cold rolling mill ready signal is blocked in recoiling mode.

[0024] As a preferred solution for the method of implementing strip recoiling in a cold rolling skin-pass mill, in the recoiling mode:

[0025] Carry out single-action and linkage logic adjustments on the entire line;

[0026] Adjust the conditions for establishing a business.

[0027] As a preferred solution for the method of realizing strip recoiling by the cold rolling and skin-pass mill, in the recoiling mode, the operating speed of the cold rolling and skin-pass mill is limited to no more than 500 MPM.

[0028] The present invention has the following advantages: by controlling the cold-rolling skin-pass mill to enter the rewinding mode, in the rewinding mode, the cold-rolling skin-pass mill is controlled to throw off the speed master command given, and the speed master command given is sent to the coiler, thereby releasing the tension control of the coiler; in the upper threading mode, the uncoiler tension is established, and the coiler maintains static tension; in the lower threading mode, the uncoiler / entry tension roller / exit tension roller establish tension, and the coiler maintains static tension; the upper working roll of the cold-rolling skin-pass mill is withdrawn, and the lower working roll of the cold-rolling skin-pass mill is retained. After the steel strip is threaded, the lower working roll is lowered to the lowest position. The present invention uses the coiler as the speed control master signal to realize the rewinding function of the entire line, which can activate the production capacity of the skin-pass mill unit, eliminate the need for cumbersome roll-changing mode to operate the rolls, and greatly improve the production rhythm of the entire cold rolling. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0030] Figure 1 A schematic flow chart of a method for implementing strip recoiling in a cold rolling skin-pass mill according to an embodiment of the present invention;

[0031] Figure 2 Schematic diagram of determining the speed master command in the method for realizing strip recoiling in a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the coiler tension in the method for recoiling a strip steel in a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0033] Figure 4 A logic diagram for disconnecting the main drive operation of a rolling mill in a method for realizing strip recoiling in a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0034] Figure 5 A logic diagram of a lubrication control system for a cold rolling mill in a method for recoiling a strip steel in a skin-pass mill provided in an embodiment of the present invention;

[0035] Figure 6 A logic diagram of the interlocking operation signals of a shielded rolling mill motor in a method for realizing strip recoiling of a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0036] Figure 7 A parking logic diagram for adjusting a method for implementing strip recoiling of a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0037] Figure 8 A logic diagram of a shielded rolling mill ready signal in a method for realizing strip recoiling in a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0038] Figure 9 A diagram of the whole-line single-action and linkage logic adjustment in the method for realizing strip recoiling of a cold-rolling skin-pass mill provided in an embodiment of the present invention;

[0039] Figure 10 A diagram for adjusting the sheeting conditions in a method for implementing strip recoiling in a cold rolling skin-pass mill provided in an embodiment of the present invention;

[0040] Figure 11 This is a logic diagram of speed limiting in a method for implementing strip recoiling in a cold rolling skin-pass mill provided in an embodiment of the present invention. Implementation Method

[0041] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0042] The existing cold rolling and tempering process layout could no longer meet production needs, restricting the production pace. This also resulted in the tempering mill's output being limited. The rewinding line was unable to maximize its production capacity due to the high volume of repaired coils.

[0043] The cold rolling skin-pass mill operates in a mode where the mill speed is the primary command, with other drives on the line, such as the uncoiler, tension roller, and coiler, following suit. Adjusting the transmission control mode is one of the difficulties. In skin-pass mode, the entire production line operates in a constant tension control mode, and the coiler tension control uses a speed saturation torque limiter mode to maintain constant strip tension. Setting the tension in rewinding mode and ensuring constant strip tension during rewinding is also a challenge. Unwinding a mill involves numerous interlocking systems, such as the transmission system, production line preparation, emergency and quick stop controls, mill interlocks, oil and gas lubrication, and full-line inching. At the same time, because the roll gap is open in rewinding mode, the strip will vibrate, and preventing vibration from hitting the rolls also requires consideration.

[0044] In view of this, an embodiment of the present invention provides a method for a cold rolling and skin-pass mill to achieve strip recoiling, thereby solving the problem that a traditional cold rolling and skin-pass mill cannot fully utilize its production capacity, resulting in waste of production capacity.

[0045] See also Figure 1 、 Figure 2 and Figure 3This embodiment provides a method for re-coiling a cold rolling mill, comprising the following steps:

[0046] S1. Controlling the cold rolling and tempering mill to enter a rewinding mode. In the rewinding mode, the cold rolling and tempering mill is controlled to throw off the speed master command, send the speed master command to the coiler, and release the tension control of the coiler;

[0047] S2: In the upper threading mode, the uncoiler tension is established and the coiler maintains static tension; in the lower threading mode, the uncoiler / entry tension roller / exit tension roller establish tension and the coiler maintains static tension;

[0048] S3. Withdraw the upper working roll of the cold rolling mill and retain the lower working roll of the cold rolling mill. After threading the steel strip, lower the lower working roll to the lowest position.

[0049] Assist Figure 2 In step S1 of this embodiment, because the recoiling mode is independent of the rolling mill, the speed command for the cold rolling and skin-pass production line is implemented by the coiler. Specifically, when the recoiling mode is selected, the rolling mill automatically disengages the speed command. The speed command is then sent to the coiler, and the coiler's tension control mode is simultaneously released. Other transmission systems on the production line remain unchanged.

[0050] Assist Figure 3 In this embodiment, because the coiler is speed-controlled, the strip tension in the skin-pass mill changes from four levels of tension (unwinding tension, entry tension roller tension, exit tension roller tension, and coiler tension) to three levels of tension (unwinding tension, entry tension roller tension, and exit tension roller tension). Specifically, the threading mode generates tension T1 at the unwinder, T2 at the entry tension roller, and T3 at the exit tension roller. The total tension in the skin-pass mill line is T1 + T2 + T3.

[0051] In this embodiment, the tension T1 generated by the uncoiler is set by multiplying the continuous rolling coil tension by an empirical coefficient, with the empirical coefficient ranging from 0.8 to 1.0. The tension T2 generated by the entrance tension roller is preset to 1.0 to 1.2 times the tension before the rewinding mode; the tension T3 generated by the exit tension roller is preset to 1.0 to 1.2 times the tension before the rewinding mode.

[0052] During the tensioning process, simply press the entry tensioning button. In upper threading mode, tension is established on the uncoiler, and the winder is enabled and maintains static tension. Simultaneously, press the entry tensioning button. In lower threading mode, tension is established on the uncoiler, entry tension roller, and exit tension roller. In lower threading mode, tension is established on the winder, and the winder is enabled and maintains static tension.

[0053] In step S3 of this embodiment, after the lower work roll is lowered to the lowest position, the upper work roll is directly withdrawn without switching to the roll changing mode. In the rewinding mode, the height of the entrance anti-wrinkle roll is adjusted to a specified position before the cold rolling mill is accelerated.

[0054] Specifically, after the rolling mill is unloaded, the upper work roll is first pulled out, while the lower work roll is retained. The purpose of pulling out the upper work roll is to prevent the strip from vibrating and damaging the roll. The lower work roll is retained to ensure smooth strip threading. After the strip is threaded, the lower roll is lowered to the lowest position.

[0055] In order to better facilitate the operators, the roll withdrawal and other related operations can be performed in the rewinding mode without switching to the roll changing mode. It should be noted that after switching to the roll changing mode, the two connecting shaft supports of the main rolling mill need to be retracted to the lowest position.

[0056] When rewinding mode is selected, the upper work roll is withdrawn and the lower work roll is lowered. The remaining operations are the same as normal rolling. Because the mill rolls are not pressing down on the strip, the strip will vibrate inside the mill. Therefore, the height of the entry anti-wrinkle roll must be adjusted before increasing the speed to reduce strip vibration.

[0057] In this embodiment, the rolling mill needs to be swung off when operating in the rewinding mode, so the rolling mill transmission system, the rolling mill hydraulic pressure system, the rolling mill lubrication system, and the line operation chain need to be adjusted.

[0058] See also Figure 4 , in order to throw off the main drive operation interlocking logic of the cold rolling mill; when the rewinding mode is selected, the MILL-RDYRUN signal is invalid and is directly set to 1;

[0059] See also Figure 5 , in order to get rid of the lubrication control system logic of the cold rolling mill; when the rewinding mode is selected, all OIL_AIR (oil and air lubrication system) signals are invalid and directly set to 1;

[0060] See also Figure 6 , to shield the motor operation signal interlock of the cold rolling mill; when the rewinding mode is selected, some signals of the main motor of the rolling mill are shielded and directly set to 1.

[0061] See also Figure 7 , to adjust the parking logic in rewinding mode; when rewinding mode is selected, all the quick stop shielding (RGC\RBC, rolling mill motor lubrication) and other signals of the rolling mill are invalid and are directly set to 1.

[0062] See also Figure 8 , for the rewinding mode, the cold rolling mill ready signal shielding logic is performed; when the rewinding mode is selected, the temperature, water leakage inspection, air gap inspection, and three-phase winding temperature detection signals of the rolling mill motor are invalid and are directly set to 1;

[0063] See also Figure 9 , in order to adjust the logic for single action and linkage logic of the entire line;

[0064] See also Figure 10 , in order to adjust the logic of the establishment conditions;

[0065] See also Figure 11 To limit the speed of the cold-rolling skin-pass mill to no more than 1100 MPM, a multiplexer is configured. When rewinding mode is selected, A2 is set to 1, which connects to the output of IA2. IA2 is set to 500 MPM (the smaller of 1100 MPM and 500 MPM). The 500 MPM limit can be adjusted based on the operating conditions.

[0066] Practice shows that from September to October 2022, the specific situation of production in the cold rolling and skin-pass mill using the technical solution of this embodiment is as follows: a total of 4,155 tons of repaired and re-flattened steel coils were produced in two months. The steel coil brands and the total production volume of each brand are as follows:

[0067] Through the above technical means, this embodiment enables a rewinding function for a cold-rolling skin-pass mill without substantially changing existing operating habits. Switching between normal rolling mode and rewinding mode is simple and convenient with a single button. The rewinding speed is adjustable, reaching a maximum of 500 MPM, exceeding the rewinder unit's maximum speed of 460 MPM and still allowing for further speed increases. The coiler serves as the master speed control signal for achieving rewinding functionality across the entire line. The conditions for switching to rewinding mode are clearly listed on the human-machine interface, eliminating the need for cumbersome roll-changing operations, improving production efficiency.

[0068] In summary, the present invention controls a cold skin pass mill to enter recoiling mode. In this mode, the cold skin pass mill is controlled to disengage the speed master command and transmit the speed master command to the coiler, releasing the coiler's tension control. In the upper threading mode, tension is established in the uncoiler, while the coiler maintains static tension. In the lower threading mode, tension is established in the uncoiler, the entry tension roller, and the exit tension roller, while the coiler maintains static tension. The upper work roll of the cold skin pass mill is withdrawn, while the lower work roll remains. After strip threading, the lower work roll is lowered to its lowest position. Since the coiler is speed-controlled, the strip tension in the cold skin pass mill changes from four levels of tension (uncoiler tension, entry tension roller tension, exit tension roller tension, and coiler tension) to three levels of tension (uncoiler tension, entry tension roller tension, and exit tension roller tension). Specifically, in the lower threading mode, tension T1 is generated at the uncoiler, T2 at the entry tension roller, and T3 at the exit tension roller. The total tension of the cold skin pass mill line is: T1 + T2 + T3. During the mill tensioning process, simply press the entry tensioning button. In upper threading mode, tension is established at the uncoiler, while the coiler is enabled and maintains static tension. Simultaneously, press the exit tensioning button. In lower threading mode, tension is established at the uncoiler, entry tension roller, and exit tension roller, while the coiler is enabled and maintains static tension. After unwinding the mill, the upper work roll is first withdrawn, while the lower work roll remains. The upper work roll is withdrawn to prevent strip vibration and roll damage, while the lower work roll remains to ensure smooth threading. After threading is complete, the lower work roll is lowered to its lowest position. When rewinding mode is selected, the upper work roll is withdrawn and the lower work roll is lowered. The remaining operations are the same as for normal rolling. Because the mill rolls are not pressing the strip, the strip will vibrate within the mill. Therefore, the height of the entry anti-wrinkle roll should be adjusted before increasing the speed to minimize strip vibration. The present invention uses the coiler as the speed control main signal to realize the rewinding function of the entire line, which can activate the production capacity of the leveling unit and does not require the cumbersome roll-changing mode to operate the rolls, thereby greatly improving the production rhythm of the entire cold rolling.

[0069] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for re-coiling steel strips using a cold rolling mill, characterized in that: include: Controlling the cold rolling and tempering mill to enter a rewinding mode. In the rewinding mode, the cold rolling and tempering mill is controlled to throw off the speed master command, send the speed master command to the coiler, and release the tension control of the coiler; In the upper threading mode, the uncoiler tension is established and the coiler maintains static tension; in the lower threading mode, the uncoiler / entry tension roller / exit tension roller establish tension and the coiler maintains static tension. Pull out the upper working roll of the cold rolling mill and keep the lower working roll of the cold rolling mill. After threading the steel strip, lower the lower working roll to the lowest position. In the rewinding mode, the coiler enters the speed control state, and the strip tension on the cold rolling mill changes from four tension levels to three tension levels: The tension in the down-threading mode is generated at the uncoiler, T1; the inlet tension roller generates T2; the outlet tension roller generates T3. The total tension of the cold rolling mill production line is: T1+T2+T3; The tension T1 generated by the uncoiler is set by multiplying the continuous rolling coil tension by the empirical coefficient, and the empirical coefficient is set between 0.8 and 1.0; The tension T2 generated by the entrance tension roller is preset to 1.0 to 1.2 times the tension before the rewinding mode; The tension T3 generated by the outlet tension roller is preset to be 1.0 to 1.2 times the tension before the rewinding mode.

2. The method for recoiling steel strips by a cold rolling and skin-passing mill according to claim 1, characterized in that: After the lower working roll is lowered to the lowest position, the upper working roll is directly withdrawn without switching the rewinding mode to the roll changing mode.

3. The method for recoiling steel strips by a cold rolling and skin-passing mill according to claim 2, characterized in that: In the rewinding mode, the height of the entrance anti-wrinkle roller is adjusted to a specified position before the cold rolling mill is accelerated.

4. The method for recoiling steel strips by a cold rolling and skin-passing mill according to claim 1, characterized in that: In the rewind mode: Disconnect the main drive operation chain of the cold rolling mill; Throw away the lubrication control system of the cold-rolling skin-pass mill; Shield the motor operation signal interlock of the cold rolling mill.

5. The method for recoiling steel strips by a cold rolling and skin-passing mill according to claim 4, characterized in that: In the rewind mode: Adjust the parking logic in rewind mode; The cold rolling mill ready signal is blocked in recoiling mode.

6. The method for recoiling steel strips by using a cold rolling and skin-pass mill according to claim 5, characterized in that: In the rewind mode: Carry out single-action and linkage logic adjustments on the entire line; Adjust the conditions for establishing a business.

7. The method for recoiling steel strips by a cold rolling and skin-pass mill according to claim 6, characterized in that: In the recoiling mode, the operating speed of the cold rolling mill is limited to no more than 500 MPM.

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