A method for adjusting the threading of a single stand rolling mill

Abstract

The present application relates to the production technology field of cold rolling mill, especially to a single stand rolling mill strip head threading adjustment method, including adjusting the strip head into single bending point strip head adjustment and double bending point strip head adjustment two modes, the strip head angle adjustment selects single bending point strip head mode or double bending point strip head mode according to the strip shape and steel grade, sets the bending point position and bending angle based on the relative position of pinch roll, straightening roll and guide plate, makes the strip head form the upward posture that adapts to the threading path, and carries out the steel clamping positioning processing, according to the corresponding treatment mode of the position matching of the steel clamping, the strip can be reset quickly without completely exiting, the present application can improve the threading operation efficiency, reduce the downtime and equipment damage caused by the steel clamping, and also can significantly improve the overall operation efficiency of the rolling mill.

Description

Technical Field

[0001] This invention relates to the field of cold rolling mill production technology, and in particular to a method for adjusting the strip threading of a single-stand rolling mill. Background Technology

[0002] Strip threading is a critical operation in cold rolling mill production, directly impacting the mill's efficiency. Therefore, improving strip threading efficiency is equivalent to improving mill efficiency. The key to strip threading lies in adjusting the strip head and handling strip jamming. Proper strip head adjustment reduces strip jamming during threading, thus improving efficiency. Conversely, if strip jamming does occur, proper handling will further increase threading efficiency.

[0003] Existing strip head adjustment methods have a low success rate, frequently causing strip jamming and downtime, with an average downtime of 6 minutes. Furthermore, the risk of strip jamming scraping the equipment significantly reduces strip threading efficiency, leading to unnecessary equipment damage and disrupting the overall production rhythm of the rolling mill. Keyword searches reveal a lack of research on strip head adjustment and strip jamming handling in cold rolling strip threading operations; no similar content was found. Therefore, there is an urgent need for a strip head adjustment and strip jamming handling method that, without requiring equipment upgrades, improves strip threading efficiency while also being simple and convenient to operate. Summary of the Invention

[0004] This invention provides a method for adjusting the strip threading of a single-stand rolling mill. It addresses the problems of low strip threading efficiency, steel jamming, and equipment damage caused by this issue in single-stand cold rolling mills. Based on existing equipment capabilities, the method optimizes equipment functions and operating methods. This approach not only improves strip threading efficiency but also reduces downtime and equipment damage caused by steel jamming, significantly enhancing the overall operating efficiency of the rolling mill.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for adjusting the strip threading of a single-stand rolling mill includes the following steps: (1) Strip head adjustment optimization: The strip head adjustment is divided into two modes: single bending point strip head adjustment and double bending point strip head adjustment. The single bending point strip head adjustment is to bend the strip head 150-200mm past the pinch roll as the bending point, and bend the strip head upward by 20-25°. The strip remains straight for 700-800mm after the bending point. The double-bending-point belt head adjustment involves driving the belt head 180-220 mm past the pinch roller as the first bending point, bending the strip head upwards by 15-20°, and then driving the strip forward 600-700 mm to this point as the second bending point. The strip head is then bent upwards by 10-15°. It is ensured that the belt head angle at the first bending point remains unchanged, and that the arch height of the strip between the two bending points is lower than the upturn height of the strip head at the first bending point. (2) Steel jamming treatment optimization: When steel jamming occurs before the inlet strip clamping device, it is determined that the head lifting angle is insufficient, and the head lifting angle of the strip is directly increased; When the strip gets stuck inside the anti-tangling guide plate at the entrance, it is determined that the bending angle is too large. There is no need to completely pour out the head of the strip and readjust it. Instead, use the strip clamping device to lower the bending point and continue threading the strip. When the steel gets stuck at the roll gap, it is determined that the front end is too long. There is no need to turn the head of the strip out for adjustment. Instead, lift the roll gap by 20-30mm and then thread the strip again. When the strip gets stuck at the pre-exit guide plate, the strip head is turned back 300-400mm to the roll gap. The strip is then centered through the inlet guide plate. The minimum rolling force is used to press the strip at this point. After correcting the head angle, the strip continues to be threaded.

[0006] Furthermore, the single-bend point belt head adjustment is suitable for belt heads with a straight 1000mm plate shape, no buckle or upturned head, or for non-first-pass belt threading and accident handling scenarios.

[0007] Furthermore, the double-bend point adjustment is suitable for scenarios where the belt head shape is poor or there are buckles / curved ends.

[0008] Furthermore, the inlet and outlet anti-tangling guides remain extended throughout the entire tape-threading process.

[0009] Furthermore, before the strip head is inserted into the jaws at the exit guide plate, it is essential to use the exit side guide plate to center the strip before inserting it into the jaws.

[0010] Compared with the prior art, the beneficial effects of the present invention are: By employing two optimized strip head adjustment schemes and optimizing the strip clamping and positioning process according to this invention, the strip threading efficiency is significantly improved. The superior adjustment schemes also reduce scratching during the threading process, minimizing unnecessary equipment and roll damage, and indirectly reducing production costs. Comparison of actual threading operation data shows that the optimized method achieves a threading success rate of 89%, while the original method achieves 69%. The strip clamping time is also significantly shortened, demonstrating a remarkable improvement. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the single-bend point head structure described in this invention.

[0012] Figure 2 This is a schematic diagram of the structure of the double-bending point head described in this invention.

[0013] In the diagram: 1. Pinch roller; 2. Straightening roller; 3. Guide plate; 4. Single bending point; 5. Bending point a; 6. Bending point b. Detailed Implementation

[0014] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings: Adjusting the angle of the strip head during the strip threading operation is crucial. Improper adjustment can easily scratch the equipment, causing strip jamming, thus reducing threading efficiency and even damaging the equipment. When strip jamming occurs, the average downtime for troubleshooting is 6 minutes, severely impacting production rhythm. This invention provides a strip threading adjustment method for a single-stand rolling mill. The strip threading adjustment method specifically includes the following: 1. Strip head adjustment and optimization; Based on the existing equipment arrangement from the inlet to the outlet of the single-stand rolling mill, as well as the vertical and horizontal positions of each piece of equipment, the strip head adjustment is divided into two types: single-bend point strip head and double-bend point strip head. If the equipment position changes, corresponding adjustments can be made at any time according to the changes in strip threading efficiency.

[0015] 1.1 Single Bending Point Leading Strip: This method can be used when the strip head, approximately 1000mm long, is visually straight, without buckles or curling, or in situations other than the first pass of strip threading or accident handling. The specific adjustment method is as follows: First, move the strip head 150-200mm past the pinch roller 1, taking this point as the single bending point 4. Use the straightening roller 2 to bend the strip head upwards by 20°, retract the straightening roller 2, and then move the strip head to the front end of the guide plate 3. Confirm the angle. If the strip head angle does not change, and the strip is visually straight for 800mm after the bending point, it is suitable. See [link to relevant documentation]. Figure 1 .

[0016] If the angle adjustment is not appropriate or the strip head shape deteriorates after adjustment, the straightening roller 2 can be used to correct it to the appropriate range according to the above standards, or the double bending point adjustment method can be used instead.

[0017] 1.2, Double-bend point head; Double-bend strip head adjustment is widely used due to its strong adaptability. It can be used regardless of whether the strip head is straight or has a buckled or upturned end. However, the adjustment procedure is more complex than that of single-bend strip head adjustment. The specific adjustment method is as follows: First, drive the strip head through 180-220 mm of the pinch roller 1, marking this as the first bend point, denoted as bend point a5. Use straightening roller 2 to bend the strip head upwards by 15°, then retract straightening roller 2. Next, drive the strip forward 600 mm, marking this as the second bend point, denoted as bend point b6. Use straightening roller 2 to bend the strip head upwards by 10°, then retract straightening roller 2. Then, drive the strip to the front end of the guide plate 3. Ensure that the strip head angle at the first bend point remains unchanged. The appropriate adjustment is to ensure that the arch height of the strip between the two bend points is lower than the upturn height of the strip head at the first bend point. See [link to relevant documentation]. Figure 2 .

[0018] If the angle of the first bending point is not appropriate, or if the arching height of the strip between the two bending points is higher than or equal to the head-up height of the front strip, then the straightening roller 2 needs to be readjusted to the appropriate range according to the above standards.

[0019] Both of the above-mentioned lead adjustment methods have achieved good results in production practice. The single-bend point lead adjustment is convenient and more suitable for use with harder steels such as silicon steel and high-strength steel, or for use in accident handling and non-first pass threading. Although the double-bend point lead adjustment is slightly less efficient than the former, it can adapt to the threading needs of various plate shapes, and is especially suitable for use with low carbon steel.

[0020] 2. Optimization of steel clamping process; Even after adjusting the belt head using the above methods, scratching or jamming of the steel cannot be completely avoided during the threading process. Methods for handling jamming include the following: 2.1 Before the strip steel clamping device reaches the entrance, it can be determined that the small angle of the strip steel head is the cause, and the angle of the strip steel head needs to be increased.

[0021] 2.2 If the strip gets stuck at the machine frame entrance, it can be determined that the strip shape within 1000mm of the strip head is poor, and it needs to be straightened again according to the strip head adjustment method.

[0022] 2.3 If the strip is stuck inside the anti-tangling guide plate at the entrance, it can be determined that the bending angle of the strip head is too large. In this case, it is not necessary to completely pour out the strip head for readjustment. The strip clamping device can be used to press down the bending point of the strip, and then the threading operation can continue. This can save more time and increase efficiency.

[0023] 2.4. If the strip gets stuck at the roll gap, it's because the leading edge of the strip is too long. In this case, there's no need to turn the strip head out for adjustment. You can lift the roll gap by 20-30 mm and try threading the strip again. The success rate is very high, thus saving more time.

[0024] 2.5. The strip getting stuck at the pre-exit guide plate is caused by a change in the angle of the strip head as it passes through the roll gap, resulting in a smaller angle and causing the strip to get stuck. Alternatively, it could be due to scraping during the threading process. The solution is to turn the first 300-400 mm of the strip head towards the roll gap, first use the inlet guide plate to center the strip, and then use the minimum rolling force to press this area. This will solve the problems of the strip head angle becoming smaller and scraping during the threading process, avoiding the trouble of turning the strip out and readjusting.

[0025] 2.6 Throughout the entire strip threading process, keep the inlet and outlet anti-tangling guide plates extended as much as possible. In most cases, this not only facilitates the smooth passage of the strip head but also protects the rolls and reduces the possibility of them being scratched by the strip head.

[0026] 2.7 When the strip head is threaded to the exit guide plate and enters the jaws, the strip must be aligned with the exit guide plate before being threaded into the jaws. This will not only reduce scratches but also reduce the risk of deviation.

[0027] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0028] Example: The optimization and adjustment of strip head threading and strip jamming treatment in single-stand rolling mills are shown in the table below: Table 1. Steps 1 to 2 of the optimal implementation method for strip head optimization and steel jamming treatment in single-stand rolling mills:

[0029] Table 2. Step 3 of the optimal implementation method for strip head optimization and steel jamming treatment in single-stand rolling mills:

[0030] Currently, research on the adjustment of the strip threading head and the handling of stuck steel in cold rolling mills is still lacking. Therefore, there is no specific comparison with existing technologies. Existing strip threading adjustment schemes lack detailed classification and precise, fixed adjustment methods, relying entirely on accumulated experience, resulting in significant randomness and a substantial impact on production efficiency and pace. Existing methods for handling stuck steel rely on manual labor using tools such as crowbars, which is inefficient and poses safety hazards. Improving strip threading efficiency through equipment upgrades requires substantial financial investment and losses due to downtime and adjustments, with no guarantee of a guaranteed improvement. Therefore, utilizing existing equipment capabilities and employing this method to improve the strip threading efficiency of single-stand rolling mills is the optimal choice. The optimized method of this invention is fundamentally superior to existing technologies, significantly improving strip threading efficiency, reducing downtime caused by stuck steel, and enhancing the overall operating efficiency and production pace of the rolling mill. By comparing the actual tape threading operation data of the optimized method and the existing method, it was found that the tape threading success rate of the optimized method was 89%, while that of the original method was 69%, showing a significant improvement. At the same time, the reduction in scratches during the tape threading process also reduced equipment damage and roll damage, indirectly lowering production costs.

Claims

1. A method for adjusting the strip threading of a single-stand rolling mill, characterized in that, Includes the following steps: (1) Strip head adjustment optimization: The strip head adjustment is divided into two modes: single bending point strip head adjustment and double bending point strip head adjustment. The single bending point strip head adjustment is to bend the strip head 150-200mm past the pinch roll as the bending point, and bend the strip head upward by 20-25°. The strip remains straight for 700-800mm after the bending point. The double-bending-point belt head adjustment involves driving the belt head 180-220 mm past the pinch roller as the first bending point, bending the strip head upwards by 15-20°, and then driving the strip forward 600-700 mm to this point as the second bending point. The strip head is then bent upwards by 10-15°. It is ensured that the belt head angle at the first bending point remains unchanged, and that the arch height of the strip between the two bending points is lower than the upturn height of the strip head at the first bending point. (2) Steel jamming treatment optimization: When steel jamming occurs before the inlet strip clamping device, it is determined that the head lifting angle is insufficient, and the head lifting angle of the strip is directly increased; When the strip gets stuck inside the anti-tangling guide plate at the entrance, it is determined that the bending angle is too large. There is no need to completely pour out the head of the strip and readjust it. Instead, use the strip clamping device to lower the bending point and continue threading the strip. When the steel gets stuck at the roll gap, it is determined that the front end is too long. There is no need to turn the head of the strip out for adjustment. Instead, lift the roll gap by 20-30mm and then thread the strip again. When the strip gets stuck at the pre-exit guide plate, the strip head is turned back 300-400mm to the roll gap. The strip is then centered through the inlet guide plate. The minimum rolling force is used to press the strip at this point. After correcting the head angle, the strip continues to be threaded.

2. The method for adjusting the strip threading of a single-stand rolling mill according to claim 1, characterized in that, The single-bend point adjustment is suitable for situations where the belt head is 1000mm thick, the plate is straight, there are no buckles or upturned ends, or it is not the first time the belt is threaded, or in accident handling scenarios.

3. The method for adjusting the strip threading of a single-stand rolling mill according to claim 1, characterized in that, The double-bend point adjustment is suitable for scenarios where the belt head shape is poor or there are buckles / curved ends.

4. The method for adjusting the strip threading of a single-stand rolling mill according to claim 1, characterized in that, Throughout the entire threading process, the inlet and outlet anti-tangling guide plates remain extended.

5. The method for adjusting the strip threading of a single-stand rolling mill according to claim 1, characterized in that, The strip head is passed through the exit guide plate and before entering the jaws, the strip is centered using the exit side guide plate.

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