Method for quickly removing foreign matter on the surface of a continuous wetting and flattening work roll online

Abstract

This invention relates to a method for rapidly eliminating foreign matter on the surface of continuous wet leveling work rolls online, specifically as follows: 1) After the leveling machine completes the roll contact, the leveling liquid spraying system is automatically activated; 2) After the leveling machine completes the roll contact, the tension set values ​​for the inlet, middle, and outlet sections of the leveling machine are set to the total value calculated by multiplying the unit tension by the cross-sectional area of ​​the strip steel; 3) When the leveling machine completes the roll contact and starts to accelerate, if the outlet section speed reaches 70 MPa or above, and if the leveling machine's No. 1 and No. 2 frames use elongation control, the leveling machine elongation control is put into use; 4) When the outlet speed reaches the set maximum value, the roller speed is consistent with the strip steel speed. At this time, the surface of the strip steel is checked by observing the surface inspection instrument and online inspection until the roller marks are eliminated by the surface inspection instrument or no roller marks are visible in the online inspection. Then, the cyclic acceleration and deceleration are stopped and normal production is resumed. This achieves the goal of making the outline of the surface of the strip steel increasingly smaller until it is eliminated, and the speed of the unit's process section can be increased in a timely manner, thereby improving the unit's production capacity.

Description

Technical Field

[0001] This invention relates to a method, specifically a method for rapidly removing foreign matter from the surface of a continuous wet leveling work roller online, belonging to the technical field of removing foreign matter from the roller surface. Background Technology

[0002] Tinplate is a high-quality product with excellent coating properties, primarily used in packaging materials for food cans, chemical paints, pharmaceuticals, and household appliances. To improve the quality and coating performance of incoming tinplate, effectively reduce or eliminate surface defects, and increase surface roughness, tinplate requires leveling during production. High-end tinplate is often used for outer packaging. To further enhance the aesthetics of tinplate packaging, wet leveling is typically used in continuous annealing processes to prevent rust and impart a certain degree of roughness to the strip surface. However, in actual use, the surrounding environment of the leveling machine is relatively humid. With environmental changes, aerosols or grease may condense on the machine's surface. Once these foreign objects detach from the machine's surface, they fall onto the running strip. When a leveling machine automatically changes its work rolls, the machine's up-and-down movement causes foreign objects to fall onto the strip surface due to vibration. After leveling, these objects leave impurities on the strip surface. Minor impurities affect the strip's surface finish, while severely impurities render the strip unusable and require scrapping. If foreign objects fall from the machine and stick to the roll surface, timely removal can reduce the length of the impurity mark and even eliminate the risk of further foreign object fallout or roll marks from the roll itself when replacing with a new roll. Therefore, to eliminate impurity marks, the leveling machine needs to be cleaned regularly with dry ice. To reduce the length of the impurity mark, the contact pressure between the leveling machine rolls and the strip, as well as the operating speed, need to be adjusted.

[0003] Existing technologies use the time during which the strip speed is increased to eliminate foreign objects on the roll surface. However, since this time of speed increase is only the period when the working roll speeds up to the maximum set speed and the strip steel is driven to the maximum set speed, there is relative sliding friction. However, the friction time is short. When the speed of the strip steel and the roll are the same, there is only static friction. At this time, the friction force is small and the effect is generally poor. This results in a long time for eliminating foreign objects on the roll surface, which increases the length of the waste marks on the strip steel surface.

[0004] The search revealed patent number M00011152, titled "Control Method for Online Removal of Foreign Objects Adhering to Roller Surfaces." This method uses on-site spraying of cleaning agent and speed adjustment to remove foreign objects from the tension roller surface, but it cannot be remotely operated to remove foreign objects from the leveling machine roller surface. Therefore, a new solution is urgently needed to address this technical problem. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a method for rapidly eliminating foreign matter on the surface of continuous wet leveling work rolls online. To achieve rapid online removal of foreign matter, this solution ensures sufficient sliding friction time between the strip and the roll surface by repeatedly adjusting the speed of the roll according to the severity of the roll markings, thus achieving a repeated grinding effect on the foreign matter. However, the selection of the speed variation parameters directly affects the removal effect. Excessive speed variation will cause increased roller vibration, leading to more foreign matter adhering to the roll surface and exacerbating strip defects. Conversely, insufficient speed variation will increase the time required to eliminate foreign matter. Therefore, it is necessary to set key parameters for the speed variation process to ensure rapid removal of foreign matter.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a method for rapidly eliminating foreign matter on the surface of a continuous wet leveling work roll online, the method comprising the following steps: 1) After the leveling machine finishes its roller contact, the leveling liquid spraying system is automatically activated. Based on the spacing of the waste marks displayed on the gauge, the corresponding frame is determined. At this time, the corresponding leveling liquid spraying mode is switched from automatic to manual, the leveling liquid opening is set to 100%, and the spray flow rate is increased. The active substances in the leveling liquid are used to soak and dissolve the foreign matter on the roller surface, reducing the adhesion between the foreign matter and the roller surface. 2) After the leveling machine finishes its roller contact, the tension settings for the leveling machine inlet, middle, and outlet sections are set by multiplying the unit tension by the strip cross-sectional area (thickness * width) to obtain the total value. The unit tension setting for the leveling machine is as follows: for low-temperature materials with a thickness h < 0.21 mm, the unit tension at the leveling machine inlet is 12.1-12.8 kg / mm. 2 The unit tension of the leveling machine is 22.2-22.8 kg / mm. 2 The total tension at the leveler outlet should be set 600-1000 kg lower than the set value for the total tension at the leveler's center. For low-temperature materials with a thickness between 0.21-0.25 mm, the unit tension at the leveler inlet should be 11.7-12.5 kg / mm. 2 The unit tension of the leveling machine is 21.3-22 kg / mm. 2 The total tension at the leveler outlet should be set 800-1000 kg lower than the set total tension at the leveler center. For low-temperature materials with a thickness between 0.25-0.3 mm, the unit tension at the leveler inlet should be 11.5-12.1 kg / mm. 2 The unit tension of the leveling machine is 18-20 kg / mm. 2 The total tension at the leveler outlet should be set 600-800 kg lower than the set value for the total tension at the leveler's center. For strips thicker than 0.3 mm, the unit tension at the leveler inlet should be 10-11.5 kg / mm. 2 The unit tension of the leveling machine is 15-18 kg / mm. 2 The total tension at the leveler outlet should be set 100-300 kg lower than the set value for the total tension at the leveler's center.

[0007] 3) When the leveling mill starts and accelerates using the rollers, once the exit section speed reaches 70 MPa or higher, if the leveling mill's 1st and 2nd stands use elongation control, the elongation control is activated. The leveling mill's rolling force gradually increases according to the feedback value of the elongation to reach the target elongation. During this period, the exit section speed reaches its maximum, and the contact force between the roller surface and the strip gradually increases to the rolling force required for the target elongation. The rollers drive the strip at increasingly higher speeds, and the friction between the roller surface and the strip increases. This friction helps to remove foreign matter from the roller surface.

[0008] 4) When the exit speed reaches the set maximum value, the roller and strip speed are synchronized. At this point, the surface of the strip is inspected for foreign matter marks using a surface inspection instrument and online inspection. If foreign matter marks are present, the exit looper speed is changed to 0 MPa. When the exit speed drops to the speed of the central section, the exit speed is immediately changed to 200 MPa. When the exit speed reaches the set maximum value, the exit speed is immediately changed back to 0 MPa. By continuously increasing and decreasing the exit looper speed, the strip speed is constantly changed by adjusting the roller speed. When the exit roller speeds up, it drives the strip to speed up. During the speed increase process, the speeds of the strip and roller are inconsistent, resulting in relative sliding friction. When the exit roller speeds down, the direction of the roller acceleration changes to the opposite direction of the strip's movement. This relative sliding friction between the roller surface and the strip continues until the acceleration reaches zero. The longer the friction time, the shorter the time for online removal of foreign matter from the roller surface. The cycle of increasing and decreasing speed is stopped, and normal production resumes, until the surface inspection instrument detects that the roller marks have disappeared or the online inspection shows no visible roller marks.

[0009] Compared with existing technologies, the present invention has the following advantages: 1. The method of the present invention is based on the foreign matter on the strip surface being squeezed and adhered to the roller surface by the roller surface. Combined with the friction between the roller and the strip, the foreign matter on the roller surface can be eliminated by relative movement. By increasing the contact force between the roller and the strip, the roller speeding up and down drives the strip to move and generate relative sliding friction, and increasing the leveling liquid flow rate reduces the adhesion force of foreign matter to the roller surface, thus eliminating the foreign matter adhered to the roller surface; 2. The method of the present invention can not only remotely operate the relevant parameters of the leveling machine to quickly eliminate foreign matter on the leveling machine roller surface, but also eliminate the safety risks of personnel handling on-site and the risks of unit operation; 3. The method of the present invention not only makes the outline of the waste mark on the strip surface smaller and smaller until it is eliminated, but also allows the speed of the unit process section to be increased in a timely manner, improving the unit's production capacity; 4. The method of the present invention realizes remote operation to eliminate foreign matter on the roller surface of the continuous wet leveling work roller, eliminating the safety risks of on-site human-machine combination handling of abnormal operations. The method of the present invention is simple and easy to implement, and can quickly eliminate foreign matter on the roller surface. Attached Figure Description

[0010] Figure 1This is a leveling liquid spraying system for wet leveling machines.

[0011] Figure 2 This is a schematic diagram of the strip steel running tracking screen. Detailed Implementation

[0012] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0013] Example 1: See Figure 1 , Figure 2 A method for rapidly eliminating foreign matter on the surface of wet leveling work rolls in continuous annealing is described, using the example of a strip with specifications of 0.18mm*936mm, steel grade T-4, annealing curve 1C2, length of 11000 meters, exit speed of 120mpm, and elongation target value of 1.0%±0.2. The method involves changing rolls at 240mpm in the central section, after which a surface inspection instrument detects foreign matter marks on stand number 2.

[0014] 1) After the leveling machine is aligned with the roller, the tension setting values ​​of the three sections of the leveling machine inlet, middle and outlet are set by multiplying the unit tension of each section by the cross-sectional area of ​​the strip (thickness * width).

[0015]

[0016] 2) After the leveling machine finishes its roller contact, the leveling liquid spraying system is automatically activated. After the outlet starts, the corresponding frame is determined according to the roller marking distance displayed on the instrument. At this time, the No. 2 leveling liquid spraying mode is switched from automatic to manual, and the leveling liquid opening degree is set to 100%.

[0017] 3) After the exit speed is increased, if the strip surface is found to have defects or impurities by the on-site inspection instrument and online inspection, and the defective marks still exist when the exit speed reaches 360 MPa, immediately reduce the exit speed to 0. When the exit speed is reduced to 240 MPa, immediately set the exit speed to 200 MPa. When the exit speed reaches 440 MPa, immediately set the speed to 0 and reduce the exit speed to 240 MPa. Repeat this cycle until the defects are eliminated. At this point, the exit speed should be set according to whether the exit looper has completed its looper operation, ensuring that the looper operation from the weld seam to the exit speed is completed.

[0018]

[0019] If impurities appear on the strip surface, the tension of the corresponding stand in Table 1 can be reduced by 100-200 kg, and the rolling force of the corresponding stand increased. Elongation control involves tension adjustment and rolling force adjustment. With a fixed strip elongation, strip elongation control is closely related to tension and rolling force. The higher the leveling mill tension, the lower the rolling force; conversely, the lower the leveling mill tension, the higher the rolling force. Friction is related to the normal pressure (rolling force) of the contact surface. Higher contact pressure results in greater running friction and a shorter time to eliminate foreign matter from the roll surface. Specific tension settings should be slightly adjusted based on the actual L1 rolling force and the actual elongation. When the elongation reaches the target value, the rolling force of stand 1 should not exceed 6800 kN, and the rolling force of stand 2 should not exceed 5000 kN.

[0020] Taking a strip with dimensions of 0.25mm*900mm, steel grade T-5, annealing curve 3c1, length 7000 meters, and central section process speed of 650mpm as an example, and the weld between the strip and the preceding strip at an exit speed of 180mpm and an elongation target value of 1.2% ± 0.2, as an example, surface inspection instruments detected a waste mark on stand 1 when the weld was passed through a low-speed, low-pressure leveling machine.

[0021] 1. After the leveling machine's rollers are in place, set the tension settings for the inlet, middle, and outlet sections of the leveling machine to the total value calculated by multiplying the unit tension by the cross-sectional area of ​​the strip (thickness * width):

[0022]

[0023]

[0024] 2. After the leveling machine completes the roller contact, the leveling liquid spraying system automatically starts. After the outlet starts, the corresponding frame is determined according to the roller marking distance displayed on the gauge. At this time, the leveling liquid spraying mode of frame 1 is switched from automatic to manual, and the leveling liquid opening degree is set to 100%.

[0025] 3. After the exit speed is increased, if the surface inspection instrument and online inspection show that there are defects on the strip surface, when the exit speed reaches 730 MPM, if the defects still exist, immediately reduce the exit speed to 0. When the exit speed is reduced to 240 MPM, immediately set the exit speed to 200 MPM. When the exit speed reaches 440 MPM, immediately set the speed to 0 and reduce the exit speed to 240 MPM. Repeat this cycle until the defects are eliminated. At this point, the exit speed should be set according to whether the exit looper has completed its looper operation, ensuring that the looper operation from the weld to the exit is completed.

[0026]

[0027] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for rapidly eliminating foreign matter on the surface of a continuous wet leveling work roll online, characterized in that, The method includes the following steps: 1) After the leveling machine rollers are in place, the leveling liquid spraying system is automatically activated. 2) After the leveling machine is aligned with the rollers, set the tension settings for the inlet, middle, and outlet sections of the leveling machine to the total value calculated by multiplying the unit tension by the cross-sectional area of ​​the strip. 3) When the leveler starts and accelerates using the rollers, once the exit section speed reaches 70 MPa or higher, if the first and second stands of the double-stand leveler use elongation control, the leveler elongation control is activated. The leveler rolling force gradually increases to the target elongation based on the feedback value of the elongation. During this period, the exit section speed reaches its maximum, and the contact force between the roller surface and the strip gradually increases to the rolling force required for the target elongation. The rollers drive the strip at increasingly higher speeds, and the friction between the roller surface and the strip increases. This friction helps to remove foreign matter from the roller surface. 4) When the exit speed reaches the set maximum value, the speed of the roller and the strip steel are consistent. At this time, the surface of the strip steel is checked for foreign matter marks by observing the surface inspection instrument and online inspection. If foreign matter marks are present, the exit looper speed is changed to 0 MPa. When the exit section speed drops to the speed of the middle section, the exit speed is immediately changed to 200 MPa. When the exit speed reaches the set maximum value, the exit speed is immediately changed back to 0 MPa. By continuously increasing and decreasing the exit looper speed, the speed of the strip steel is constantly changed by using the roller speed increase and decrease. When the exit roller speed increases, the roller drives the strip steel to increase speed. During the speed increase process, the speed of the strip steel and the roller are inconsistent, resulting in relative sliding friction. When the exit roller speed decreases, the direction of the roller acceleration changes to the opposite direction of the strip steel movement. The relative sliding friction between the roller surface and the strip steel continues until the acceleration is 0. The longer the friction time, the shorter the time for online removal of foreign matter on the roller surface. Until the surface inspection instrument detects that the roller marks have been removed or the roller marks are no longer visible in the online inspection, the cycle of speed increase and decrease is stopped and normal production is resumed.

2. The method for rapidly eliminating foreign matter on the surface of continuous wet leveling work rolls according to claim 1, characterized in that, Step 1) After the leveling machine finishes its roller contact, the leveling liquid spraying system is automatically activated. The corresponding frame is determined based on the spacing of the waste marks displayed on the instrument. At this time, the corresponding leveling liquid spraying mode is switched from automatic to manual, the leveling liquid opening is set to 100%, and the spraying flow rate is increased. The active substances in the leveling liquid soak and dissolve the foreign matter on the roller surface, reducing the adhesion between the foreign matter and the roller surface.

3. The method for rapidly eliminating foreign matter on the surface of continuous wet leveling work rolls according to claim 2, characterized in that, Step 2) After the leveling machine is aligned with the rollers, set the tension values ​​for the inlet, middle, and outlet sections of the leveling machine to the total value calculated by multiplying the unit tension by the cross-sectional area of ​​the strip. Specifically, the unit tension setting for the leveling machine is as follows: For low-temperature materials with a thickness h < 0.21 mm, the unit tension at the leveling machine inlet is 12.1-12.8 kg / mm. 2 The unit tension of the leveling machine is 22.2-22.8 kg / mm. 2 The total tension at the leveler outlet should be set 600-1000 kg lower than the set value for the total tension at the leveler center. For materials with a low temperature and a thickness between 0.21-0.25 mm, the unit tension at the leveler inlet should be 11.7-12.5 kg / mm. 2 The unit tension of the leveling machine is 21.3-22 kg / mm. 2 The total tension at the leveler outlet should be set 800-1000 kg lower than the set value of the total tension at the leveler center. For materials with a low temperature and a thickness between 0.25-0.3 mm, the unit tension at the leveler inlet should be 11.5-12.1 kg / mm. 2 The unit tension of the leveling machine is 18-20 kg / mm. 2 The total tension at the leveler outlet should be set 600-800 kg lower than the set total tension at the leveler center. For strips thicker than 0.3 mm, the unit tension at the leveler inlet should be 10-11.5 kg / mm. 2 The unit tension of the leveling machine is 15-18 kg / mm. 2 The total tension at the outlet of the leveling machine should be set 100-300 kg lower than the set value of the total tension in the middle of the leveling machine.

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