Method for controlling strip edge waves during loop correction process and application

Abstract

The present application belongs to the technical field of strip cold rolling production, and specifically provides a method for controlling strip edge wave in the loop correction process, comprising the following steps: (1) monitoring the generation of strip edge wave in the loop in real time; (2) if edge wave is generated, adjusting the actual swing angle β of the correction roller or the length L0 of the free strip in the loop before correction according to the strip width W and the yield strength corresponding elongation δ s . The method compares the actual swing angle of the correction roller with the safe swing angle range, adjusts the actual swing angle β or the length L0 of the free strip in the loop before correction, so that the elongation generated by correction is less than the yield strength corresponding elongation, and the generation of edge wave is reduced. The method can be used in stainless steel and carbon steel cold strip annealing units and carbon steel hot galvanizing units, solves the problem that the strip in the loop is prone to edge wave generated by correction action, can provide a reference for the design of the strip loop, maintains the original profile of the strip, and ensures the smooth passage of the strip and the smooth operation of the production line.

Description

Technical Field

[0001] This invention belongs to the field of cold rolling production technology of strip, specifically relating to a method and application for controlling strip edge waviness during looper correction process. Background Technology

[0002] Stainless steel and carbon steel cold strip annealing units, carbon steel hot-dip galvanizing units, etc., mostly use vertical loopers as strip storage equipment for continuous production line operation. Vertical loopers ensure stable operation of the production line through filling and unfilling. When the looper is empty, the distance between the straightening roller and the steering roller on the looper car is minimal. Some manufacturers, in order to save on plant costs, make the looper height relatively low, resulting in a very small distance between the straightening roller and the steering roller on the looper car, especially in the empty position. This distance is particularly small, making it easy for the strip to develop edge waviness when the straightening roller moves, thus affecting the smooth passage of the strip through the plate. Therefore, the design scheme of the straightening roller is crucial to the looper design.

[0003] Furthermore, on stainless steel strip annealing lines, excessive deflection angle of the vertical looper's straightening rollers after annealing can also cause single-sided waviness defects in the strip within the looper. This is particularly problematic when producing 400 series stainless steel, where not only single-sided waviness defects but also tensile strain mark defects may appear. A temporary solution to this problem is to reduce the amount of empty loop, increasing the distance between the looper's steering rollers and the straightening rollers, thus preventing waviness on the straightening edge. However, this solution is only a temporary measure and is difficult to apply in situations with limited factory space.

[0004] This invention optimizes the design parameters of the looper straightening roller, and combines the strip width and strip yield strength range to determine the maximum deflection angle of the straightening roller, thereby avoiding the occurrence of single-sided waviness defects in the strip within the looper. Summary of the Invention

[0005] The purpose of this invention is to avoid the occurrence of strip edge waviness defects inside the looper by optimizing the design parameters of the looper correction roller, combined with the strip width, the maximum deflection angle of the correction roller, etc.

[0006] Therefore, the present invention provides a method for controlling strip edge waviness during looper correction, comprising the following steps:

[0007] (1) Real-time monitoring of the edge wave generation of the strip inside the looper;

[0008] (2) If edge waves occur, the strip width W and the elongation δ corresponding to the strip yield strength should be considered. s Adjust the actual swing angle β of the correction roller or the length L0 of the free strip inside the loop before correction.

[0009] Specifically, in step (2) above, the yield strength σ of the strip is obtained. sBased on the elastic modulus E, the elongation δ corresponding to the yield strength of the strip is calculated. s =σ s / E.

[0010] Specifically, step (2) above is as follows: calculate the range of the safe swing angle β0 of the correction roller. If the actual swing angle β of the correction roller exceeds the range, adjust β to the range of β0. If β is within the range of β0, adjust the length L0 of the free strip in the loop before correction.

[0011] Specifically, the safe swing angle β0 of the aforementioned straightening roller is within the range of β0 < arcsin(2δ). s ×L0 / W).

[0012] Specifically, in step (2) above, if β is within the range of β0, adjust the length L0 of the free strip inside the loop before correction to L0. ’ Ensure [(W / 2)×sinβ / L0] ’ ]<δ s .

[0013] Specifically, the method for adjusting the length of the free strip inside the loop before correction is as follows: pause the operation of the loop and move the steering roller up and down to adjust the length of the free strip inside the loop.

[0014] Specifically, the aforementioned strip materials include stainless steel strip and carbon steel strip.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] The method for controlling strip edge waviness during looper correction provided by this invention is based on the strip width W, the strip yield strength, and the corresponding elongation δ. s This method calculates the safe swing angle range of the strip when the straightening roller performs the straightening action. By comparing the actual swing angle with this range, the actual swing angle β or the length L0 of the free strip within the looper before straightening is adjusted to ensure that the elongation caused by straightening is less than the elongation corresponding to the yield strength. This guarantees the smooth completion of the straightening process while reducing edge waviness. This method can be used in stainless steel and carbon steel cold strip annealing units and carbon steel hot-dip galvanizing units. It solves the problem of edge waviness caused by the straightening action of the strip within the looper, providing a reference for strip looper design, maintaining the original strip shape, and ensuring smooth strip passage and production line operation.

[0017] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the arrangement of the vertical looper inner steering roller and the correction roller.

[0019] Figure 2This is a schematic diagram showing the side arrangement of the steering roller and the straightening roller before the correction.

[0020] Figure 3 This is a schematic diagram showing the side arrangement of the steering roller and the correction roller during the correction process.

[0021] Reference numerals: 1. Directional roller; 2. Correcting roller; 3. Strip steel. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Although representative embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0023] This invention provides a method for controlling strip edge waviness during looper correction, comprising the following steps:

[0024] (1) Real-time monitoring of the edge wave generation of the strip inside the looper;

[0025] (2) According to the strip width W and the strip yield strength corresponding to the elongation δ s Calculate the range of the safe swing angle β0 of the correction roller, where β0 < arcsin(2δ). s ×L0 / W).

[0026] If edge waviness occurs, determine whether the actual swing angle β of the current straightening roller is within the range of β0. If the actual swing angle β of the straightening roller exceeds this range, adjust β to within the range of β0. If β is within the range of β0, pause the looper operation and move the guide roller up and down to adjust the length L0 of the free strip in the looper before straightening to L0. ’ Ensure [(W / 2)×sinβ / L0] ’ ]<δ s .

[0027] The effectiveness of the method for controlling strip edge waviness during the looper correction process of the present invention will be studied through specific embodiments below.

[0028] Example 1:

[0029] Stainless steel and carbon steel cold strip annealing units, and carbon steel hot-dip galvanizing units mostly use vertical loopers, such as... Figure 1 As shown, the looper steering roller is located on the upper part of the looper, and the straightening roller is fixed at the bottom of the looper. The size of the looper can be adjusted by moving the steering roller up and down. The movement of the straightening roller has a certain swing angle on the projection of the strip plane.

[0030] Reference Figure 2-3 W represents the strip width, L G L is the length of the straightening roller, and L0 is the length of the free strip inside the looper before straightening, which is also the minimum length of the free strip inside the looper. s β is the length of the long side of the strip after the straightening roller moves, and β is the swing angle of the straightening roller.

[0031] This embodiment provides a method for controlling strip edge waviness during looper correction, including the following steps:

[0032] (1)Reference Figure 2-3 W represents the width of the inner strip of the looper, determined by the product specification; L G L0 is the length of the correction roller, and L0 is the length of the free strip in the loop before correction, which is also the minimum length of the free strip in the loop. The feasible range of L0 is determined by the production line height or plant limitations.

[0033] An online strip edge wave detector is used to monitor in real time whether edge waves are generated in the inner strip of the looper.

[0034] (2) Experiments have shown that the swing angle of the straightening roller should be designed to match the length of the free strip (the distance between the steering roller of the looper and the straightening roller at the bottom of the looper) to ensure that the elongation δ generated by the strip straightening is achieved. j Elongation δ less than the yield strength of the strip s This ensures that the strip will not develop edge waves due to the correction action.

[0035] Before the correction roller is moved, it is parallel to the correction roller. After the correction roller swings, the free strip between them elongates. After the correction roller moves, it generates a swing angle β0, and the two sides of the free strip have different lengths, with the longer side having a length of L. s The length of the strip elongation ΔL = (W / 2) × sinβ0.

[0036] Therefore, the elongation δ of the strip after the straightening roller operates can be calculated. j =ΔL / L0=(W / 2×sinβ0) / L0.

[0037] By obtaining the strip yield strength σ s Based on the elastic modulus E, the elongation δ corresponding to the yield strength of the strip is calculated. s =σ s / E.

[0038] δ j <δ s The calculated range of the safe swing angle β0 of the correction roller is β0 < arcsin(2δ). s ×L0 / W).

[0039] If edge waviness is detected in the strip, the operator should be alerted to make adjustments. First, determine if the actual swing angle β of the current straightening roller is within the range of β0. If the actual swing angle β exceeds this range, adjust β to within the range of β0. If β is within the range of β0, pause the looper operation and move the guide roller up and down to adjust the length L0 of the free strip in the looper before straightening to L0. ’ Ensure [(W / 2)×sinβ / L0] ’ ]<δ s .

[0040] By promptly adjusting the correction situation, edge waviness can be reduced, waste can be minimized, and the smooth passage of strip steel and operation of the production line can be ensured.

[0041] In summary, the method for controlling strip edge waviness during the looper correction process provided by this invention relates to strip width W, strip yield strength, and elongation δ. s This method calculates the safe swing angle range of the strip when the straightening roller performs the straightening action. By comparing the actual swing angle with this range, the actual swing angle β or the length L0 of the free strip within the looper before straightening is adjusted to ensure that the elongation caused by straightening is less than the elongation corresponding to the yield strength. This guarantees the smooth completion of the straightening process while reducing edge waviness. This method can be used in stainless steel and carbon steel cold strip annealing units and carbon steel hot-dip galvanizing units. It solves the problem of edge waviness caused by the straightening action of the strip within the looper, providing a reference for strip looper design, maintaining the original strip shape, and ensuring smooth strip passage and production line operation.

[0042] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A method for controlling strip edge waviness during looper correction, characterized in that, Includes the following steps: (1) Real-time monitoring of the edge wave generation of the strip inside the looper; (2) If edge waves occur, the strip width W and the elongation δ corresponding to the strip yield strength should be considered. s Calculate the range of the safe swing angle β0 of the correction roller, where β0 < arcsin(2δ). s ×L0 / W); If the actual swing angle β of the correction roller exceeds this range, adjust β to within the range of β0; If β is within the range of β0, adjust the length L0 of the free strip inside the loop before correction to L0. ’ Ensure [(W / 2)×sinβ / L0] ’ ]<δ.

2. The method for controlling strip edge waviness during looper correction as described in claim 1, characterized in that: In step (2), the yield strength σ of the strip is obtained. s and elastic modulus E The elongation δ corresponding to the yield strength of the strip was calculated. s =σ s / E .

3. The method for controlling strip edge waviness during looper correction as described in claim 1, characterized in that, The method for adjusting the length of the free strip inside the looper before correction is as follows: pause the operation of the looper and move the steering roller up and down to adjust the length of the free strip inside the looper.

4. The method for controlling strip edge waviness during looper correction as described in claim 1, characterized in that: The strip includes stainless steel strip and carbon steel strip.

5. The method for controlling strip edge waviness during looper correction as described in any one of claims 1-4, applied in stainless steel and carbon steel cold strip annealing units and carbon steel hot-dip galvanizing units.

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