Method for reducing the transverse strip unevenness of hot-rolled steel in an acid mill train

Abstract

The application discloses a method for reducing the transverse same-plate difference of hot-rolled steel in an acid machine group, which comprises the following steps: step one, part selection; step two, transverse thickness difference debugging; step three, lifting amount adjustment; step four, elongation adjustment; step five, convexity roller replacement; step six, taper roller replacement; and step seven, same-plate difference reduction. By using taper rollers and convexity rollers of different specifications and increasing the gasket, the transverse same-plate difference of hot-rolled strip steel can be reduced to 0.012mm-0.09mm; by using the worn roller and the flat roller with large elongation, the transverse same-plate difference of hot-rolled strip steel can be reduced to 0.012mm-0.016mm, the problem that it is inconvenient to reduce the transverse same-plate difference of hot-rolled strip steel to below 0.02mm is solved, and favorable conditions are created for subsequent cold rolling to reduce the transverse same-plate difference, the precision of subsequent hot-rolled strip steel working operation is improved, and by using the worn roller, the consumption of the straightening roller is reduced by 50%, and the service life of the straightening roller is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of transverse plate difference technology, specifically a method for reducing transverse plate difference in hot-rolled steel in an acid pickling unit. Background Technology

[0002] Transverse thickness difference is the maximum value of the thickness difference between any two points in the same strip width direction. In China, the thickness difference of hot-rolled strip is between 0.025 and 0.04 mm. After cold rolling, it is difficult to reduce the thickness difference to the level required by users. In daily life, a method is needed to reduce the transverse thickness difference of hot-rolled steel in the acid pickling unit for processing hot-rolled steel.

[0003] Currently, there is a problem in the processing of hot-rolled steel that it is not easy to reduce the transverse plate difference of hot-rolled strip to below 0.02mm. This makes it impossible to create favorable conditions for reducing the transverse plate difference in subsequent cold rolling, which reduces the accuracy of subsequent processing of hot-rolled strip and thus reduces the quality of the processed hot-rolled strip. Therefore, it is necessary to invent a method to reduce the transverse plate difference of hot-rolled steel in the acid pickling unit. Summary of the Invention

[0004] The purpose of this invention is to provide a method for reducing the transverse plate difference of hot-rolled steel in an acid-pressing unit, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for reducing transverse thickness difference of hot-rolled steel in an acid mill, comprising: step one, component selection; step two, transverse thickness difference adjustment; step three, lifting amount adjustment; step four, elongation adjustment; step five, crown roll replacement; step six, taper roll replacement; and step seven, reducing thickness difference.

[0006] In step one above, two sets of rollers are used in this device: a tapered roller and a convex roller. The tapered roller has a straight surface, a diameter of 72mm at one end and 60mm at the other end, and the convex roller has an arc surface, a diameter of 72mm in the middle and 60mm at both ends. By strictly controlling the selection specifications of the tapered roller and the convex roller, it is convenient to scientifically calculate the device's operating data in the future.

[0007] In step two above, the operator measures the difference in thickness between the tapered roller and the convex roller. After the hot-rolled strip is opened for cutting, the operator measures the difference in thickness in the width direction of the strip. When the tapered roller is used to straighten the wedge-shaped difference in thickness, for strips with a larger thickness on one side and a smaller thickness on the other side, the lower straightening roller of the stretch straightener uses a tapered roller. The end of the tapered roller with a larger diameter faces the side with a larger strip thickness, and the end with a smaller diameter corresponds to the side with a smaller strip thickness. When strip steel passes through a stretch leveler, the side with the larger roll diameter experiences a greater elongation and a greater reduction in thickness, while the side with the smaller roll diameter experiences a smaller elongation and a lesser reduction in thickness. This reduces the transverse thickness difference in the strip's width direction, where one side is thicker than the other. When used for strips with a convex shape and a thinner thickness in the middle, convex rolls are used on the lower straightening rolls of the stretch leveler. As the strip passes through the stretch leveler, the middle portion of the strip's width direction experiences a greater elongation and a greater reduction in thickness, while the two sides of the strip experience a smaller elongation and a lesser reduction in thickness. This reduces the transverse thickness difference in the strip's width direction, where the middle portion is thicker than the two sides.

[0008] In step three above, the lifting amount of the lower roller of the tension leveler is adjusted according to the transverse difference of the strip. The specific implementation data is as follows:

[0009] 1. When the difference between the same plate thickness and the thickness is greater than 0.01 mm but less than 0.015 mm, the lifting amount of the lower straightening roller should be 10-12 mm.

[0010] 2. When the thickness difference between the same plate is greater than 0.015 mm and less than 0.02 mm, the lifting amount of the lower straightening roller should be 12-14 mm.

[0011] 3. When the thickness difference between the same plate is greater than 0.02 mm and less than 0.025 mm, the lifting amount of the lower straightening roller should be 14–16 mm.

[0012] 4. When the thickness difference between the same plate is greater than 0.025 mm and less than 0.03 mm, the lifting amount of the lower straightening roller is 16-18 mm. 5. When the thickness difference between the same plate is greater than 0.03 mm and less than 0.035 mm, the lifting amount of the lower straightening roller is 18-20 mm.

[0013] 6. When the difference between the same plate thickness is greater than 0.035 mm and less than 0.04 mm, the lifting amount of the lower straightening roller is 20-22 mm;

[0014] In step four above, the specific implementation data for adjusting the elongation rate of the tension leveler based on the transverse difference in the strip is as follows:

[0015] 1. When the difference in thickness between the same plate is greater than 0.01 mm and less than 0.015 mm, the elongation rate of the tension straightening machine should be set to 0.8%.

[0016] 2. When the difference in thickness between the same plate is greater than 0.015 mm and less than 0.02 mm, the elongation rate of the tension straightening machine should be set to 1.0%.

[0017] 3. When the difference in thickness between the same plate is greater than 0.02 mm and less than 0.025 mm, the elongation rate of the tension straightening machine should be set to 1.2%.

[0018] 4. When the difference in thickness between the same plate is greater than 0.025 mm and less than 0.03 mm, the elongation rate of the tension straightening machine should be set to 1.4%. 5. When the difference in thickness between the same plate is greater than 0.03 mm and less than 0.035 mm, the elongation rate of the tension straightening machine should be set to 1.6%.

[0019] 6. When the difference between the same plate thickness is greater than 0.035 mm and less than 0.04 mm, the elongation rate of the tension straightening machine should be set to 1.8%.

[0020] In step five above, due to the high tension of the stretching straightener and the cutting effect of the strip edge, the wear characteristics of the stretching straightener roll are: the wear in the middle section of the roll body is very small, while the wear on both sides of the roll body corresponding to the strip edge is very fast. The scrapped rolls of the stretching straightener are all caused by the wear on the sides of the straightener roll corresponding to the strip edge. By selecting an old straightener roll with a wear depth of 8-12mm on both sides of the roll body corresponding to the strip edge, the strip with a transverse plate difference that is higher in the middle and lower on both sides in the width direction is straightened. The thickness of the strip on both sides is reduced relatively less, while the thickness in the middle is reduced relatively more, thereby reducing the transverse plate difference of the strip and reducing the consumption of the straightener roll by 50%.

[0021] In step six above, when the thickness of one side of the hot-rolled strip is greater than that of the other side, the lower straightening roller seat is pulled out. An 8-12mm metal shim is added to the lifting mechanism on the side with greater strip thickness. Then, the lower straightening roller seat is sent into the stretch straightener and falls onto the lifting mechanism of the straightening roller. When the strip runs, the thickness of the side with greater thickness decreases more, and the thickness of the side with less thickness decreases less, thereby reducing the transverse difference of the strip and facilitating subsequent fine processing of the hot-rolled strip.

[0022] In step seven above, a flat roll without wear is used to stretch and straighten the strip under high tension. The thicker parts of the strip in the width direction bear relatively greater tension and elongate more, while the thinner parts bear relatively less tension and elongate less, thereby reducing the transverse thickness difference of the strip. Using the flat roll high elongation method, the elongation of hot-rolled strip can be reduced to 0.016mm.

[0023] Preferably, in step five, by using tapered rollers, convex rollers, and shims, the transverse difference of the hot-rolled strip is reduced to 0.012mm to 0.09mm, thus reducing the transverse difference of the strip. By using wear rollers and flat rollers with high elongation, the transverse difference of the hot-rolled strip is reduced to 0.012mm to 0.016mm, providing a high-precision processing environment for subsequent processing of the hot-rolled strip. By using wear rollers, the consumption of straightening rollers is reduced by 50%, effectively reducing the consumption of straightening rollers and extending their service life.

[0024] Preferably, step six utilizes the extension effect of the stretching straightener to perform asymmetrical stretching on the hot-rolled strip, thereby reducing the transverse thickness difference of the hot-rolled strip. After passing through the stretching straightener, the width of the hot-rolled strip remains unchanged, only the length increases and the thickness decreases. The increase in strip length is equal to the decrease in thickness: ΔL / L×100%=ΔH / H×100%=λ. According to this formula, by extending the strip more in areas with greater thickness in the width direction and extending it less in areas with less thickness, the transverse thickness difference of the strip can be reduced.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention discloses a method for reducing the transverse lateral thickness difference of hot-rolled steel in an acid-pressing unit. By using tapered and convex rollers of different specifications and adding shims, the transverse lateral thickness difference of hot-rolled strip can be reduced to 0.012mm to 0.09mm. By using worn rollers and flat rollers with high elongation, the transverse lateral thickness difference of hot-rolled strip can be reduced to 0.012mm to 0.016mm. This solves the problem of not being able to reduce the transverse lateral thickness difference of hot-rolled strip to below 0.02mm, creating favorable conditions for reducing the transverse lateral thickness difference in subsequent cold rolling, improving the accuracy of subsequent processing of hot-rolled strip, and also improving the quality of subsequent hot-rolled strip processing. By using worn rollers, the consumption of straightening rollers can be reduced by 50%, effectively extending the service life of straightening rollers and reducing the frequency of inspection by inspection personnel. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of Embodiment 1 of the method for reducing transverse plate difference of hot-rolled steel in an acid mill according to the present invention;

[0028] Figure 2 This is a schematic diagram of Example 1 of the construction process diagram for reducing transverse plate difference of hot-rolled steel in an acid pickling unit according to the present invention;

[0029] Figure 3 This is a schematic diagram of Example 2 of the construction process diagram for reducing the transverse plate difference of hot-rolled steel in an acid pickling unit according to the present invention;

[0030] Figure 4This is a schematic diagram of the construction process for reducing the transverse plate difference of hot-rolled steel in the acid mill unit according to the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Please see Figure 4 One embodiment provided by the present invention:

[0035] Example 1

[0036] To achieve the above objectives, the present invention provides the following technical solution: a method for reducing transverse thickness difference of hot-rolled steel in an acid mill, comprising: step one, component selection; step two, transverse thickness difference adjustment; step three, lifting amount adjustment; step four, elongation adjustment; step five, crown roll replacement; step six, taper roll replacement; and step seven, reducing thickness difference.

[0037] Please see Figure 1 , Figure 2 , Figure 4 ,

[0038] exist Figure 2In this device, two sets of rollers are used: a tapered roller and a convex roller. The tapered roller has a straight surface, a diameter of 72mm at one end and 60mm at the other end, while the convex roller has an arc surface, a diameter of 72mm in the middle and 60mm at both ends. By strictly controlling the selection specifications of the tapered and convex rollers, it is convenient to make subsequent scientific calculations of the device's operating data and increases the scientific rigor of the calculations made using the device.

[0039] exist Figure 1 In the process, the operator measures the thickness difference between the tapered roller and the convex roller. After the hot-rolled strip is opened for cutting, the operator measures the thickness difference in the width direction of the strip. When the tapered roller is used to straighten the wedge-shaped thickness difference, for strips with a larger thickness on one side and a smaller thickness on the other side, the lower straightening roller of the stretch straightener uses a tapered roller. The end of the tapered roller with a larger diameter faces the side with a larger strip thickness, and the end with a smaller diameter corresponds to the side with a smaller strip thickness. When strip steel passes through a stretch leveler, the side with the larger roll diameter experiences a greater elongation and a greater reduction in thickness, while the side with the smaller roll diameter experiences a smaller elongation and a lesser reduction in thickness. This reduces the transverse thickness difference in the strip's width direction, where one side is thicker than the other. When used for strips with a convex shape and a thinner thickness in the middle, convex rolls are used on the lower straightening rolls of the stretch leveler. As the strip passes through the stretch leveler, the middle portion of the strip's width direction experiences a greater elongation and a greater reduction in thickness, while the two sides of the strip experience a smaller elongation and a lesser reduction in thickness. This reduces the transverse thickness difference in the strip's width direction, where the middle portion is thicker than the two sides.

[0040] exist Figure 1 In this process, the lifting amount of the lower roller of the tension leveler is adjusted according to the transverse difference of the strip. The specific implementation data is as follows:

[0041] 1. When the difference between the same plate thickness and the thickness is greater than 0.01 mm but less than 0.015 mm, the lifting amount of the lower straightening roller should be 10-12 mm.

[0042] 2. When the thickness difference between the same plate is greater than 0.015 mm and less than 0.02 mm, the lifting amount of the lower straightening roller should be 12-14 mm.

[0043] 3. When the thickness difference between the same plate is greater than 0.02 mm and less than 0.025 mm, the lifting amount of the lower straightening roller should be 14–16 mm.

[0044] 4. When the thickness difference between the same plate is greater than 0.025 mm and less than 0.03 mm, the lifting amount of the lower straightening roller should be 16-18 mm.

[0045] 5. When the difference between the same plate size and the same plate size is greater than 0.03 mm and less than 0.035 mm, the lifting amount of the lower straightening roller is 18-20 mm. 6. When the difference between the same plate size and the same plate size is greater than 0.035 mm and less than 0.04 mm, the lifting amount of the lower straightening roller is 20-22 mm.

[0046] exist Figure 1 In this process, the specific implementation data for adjusting the elongation rate of the tension leveler based on the transverse difference in the strip thickness is as follows:

[0047] 1. When the difference in thickness between the same plate is greater than 0.01 mm and less than 0.015 mm, the elongation rate of the tension straightening machine should be set to 0.8%.

[0048] 2. When the difference in thickness between the same plate is greater than 0.015 mm and less than 0.02 mm, the elongation rate of the tension straightening machine should be set to 1.0%.

[0049] 3. When the difference in thickness between the same plate is greater than 0.02 mm and less than 0.025 mm, the elongation rate of the tension straightening machine should be set to 1.2%.

[0050] 4. When the difference in thickness between the same plate is greater than 0.025 mm and less than 0.03 mm, the elongation rate of the tension straightening machine should be set to 1.4%.

[0051] 5. When the difference in thickness between the same plate is greater than 0.03 mm and less than 0.035 mm, the elongation rate of the tension straightening machine should be set to 1.6%.

[0052] 6. When the difference between the same plate thickness is greater than 0.035 mm and less than 0.04 mm, the elongation rate of the tension straightening machine should be set to 1.8%.

[0053] exist Figure 1 In the process of stretching straightening, due to the high tension and cutting effect of the strip edge, the wear characteristics of the stretching straightening rolls are: the wear in the middle section of the roll body is very small, while the wear on the two sides of the roll body corresponding to the strip edge is very fast. The scrapped rolls of the stretching straightening machine are all caused by the wear on the two sides of the straightening roll corresponding to the strip edge. By selecting old straightening rolls with a wear depth of 8-12mm on the two sides of the roll body corresponding to the strip edge, the strip with a higher middle and lower two sides in the width direction is straightened. The thickness of the strip on both sides is reduced relatively less, while the thickness in the middle is reduced relatively more, thereby reducing the transverse difference of the strip and reducing the consumption of the straightening rolls by 50%.

[0054] exist Figure 3 In the process of hot-rolled strip steel, when one side is thicker than the other in the width direction, the lower straightening roller seat is pulled out, and an 8-12mm metal shim is added to the lifting mechanism on the side with the thicker strip steel. Then the lower straightening roller seat is sent into the stretch straightener and falls onto the lifting mechanism of the straightening roller. When the strip steel is running, the thickness of the side with the thicker strip steel decreases more, and the thickness of the side with the thinner strip steel decreases less, thereby reducing the transverse difference of the strip steel and providing convenience for subsequent fine processing of hot-rolled strip steel.

[0055] exist Figure 1In this process, unworn flat rolls are used to stretch and straighten the strip under high tension. The thicker sections of the strip in the width direction bear relatively greater tension and elongate more, while the thinner sections bear relatively less tension and elongate less, thus reducing the transverse thickness difference of the strip. Using the flat roll high elongation method, the elongation of hot-rolled strip can be reduced to 0.016 mm. The actual elongation values ​​for hot-rolled strip are as follows:

[0056] 1. When the difference between the same plate thickness is greater than 0.01 mm and less than 0.015 mm, the elongation rate of the tension straightening machine should be set to 0.96%.

[0057] 2. When the difference between the same plate thickness is greater than 0.015 mm and less than 0.02 mm, the elongation rate of the tension straightening machine should be set to 1.2%.

[0058] 3. When the difference between the same plate thickness is greater than 0.02 mm and less than 0.025 mm, the elongation rate of the tension straightening machine should be set to 1.44%.

[0059] 4. When the difference between the same plate thickness is greater than 0.025 mm and less than 0.03 mm, the elongation rate of the tension straightening machine should be set to 1.68%.

[0060] 5. When the difference between the same plate thickness is greater than 0.03 mm and less than 0.035 mm, the elongation rate of the tension straightening machine should be set to 1.92%.

[0061] 6. When the difference between the same plate thickness is greater than 0.035 mm and less than 0.04 mm, the elongation rate of the tension straightening machine should be set to 2.16%; Example 2:

[0062] Please see Figure 1 , Figure 3 , Figure 4 ,

[0063] exist Figure 1 , Figure 3 , Figure 4 In this process, by using tapered rollers, convex rollers, and shims, the transverse difference of hot-rolled strip steel is reduced to 0.012mm~0.09mm, thus reducing the transverse difference of the strip steel. By using wear rollers and flat rollers with high elongation, the transverse difference of hot-rolled strip steel is reduced to 0.012mm~0.016mm, providing a high-precision processing environment for subsequent processing of hot-rolled strip steel. By using wear rollers, the consumption of straightening rollers is reduced by 50%, effectively reducing the consumption of straightening rollers and extending their service life.

[0064] exist Figure 1In this process, the elongation effect of a stretch leveler is used to asymmetrically stretch hot-rolled strip steel, thereby reducing the transverse thickness difference of the hot-rolled strip steel. After passing through the stretch leveler, the width of the hot-rolled strip steel does not change, only the length increases and the thickness decreases. The increase in strip steel length is equal to the decrease in thickness: ΔL / L×100%=ΔH / H×100%=λ, ΔH=λ×H, where ΔL is the increase in strip steel length after passing through the stretch leveler, L is the length of the strip steel before passing through the stretch leveler, ΔH is the decrease in strip steel thickness after passing through the stretch leveler, H is the thickness of the strip steel before passing through the stretch leveler, and λ is the elongation rate of the strip steel. According to this formula, by extending the strip steel more in the width direction where the thickness is greater and extending it less in the thickness direction where the thickness is less, the transverse thickness difference of the strip steel can be reduced.

[0065] Any aspects of this invention not described in detail are well-known to those skilled in the art.

[0066] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for reducing transverse thickness difference in hot-rolled steel in an acid pickling unit, comprising: step one, component selection; step two, transverse thickness difference adjustment; step three, lifting amount adjustment; step four, elongation adjustment; step five, crown roll replacement; step six, taper roll replacement; and step seven, reducing thickness difference; characterized in that: In step one above, two sets of rollers are used in this device, namely tapered rollers and convex rollers. The tapered roller has a straight roller surface, a roller body diameter of 72mm at one end and 60mm at the other end. The convex roller has an arc roller surface, a roller body diameter of 72mm in the middle and 60mm at both ends. In step two above, the operator measures the thickness difference between the tapered roller and the convex roller. After the hot-rolled strip is opened for cutting, the operator measures the thickness difference in the width direction of the strip. When the tapered roller is used to straighten the wedge-shaped thickness difference, for strips with a larger thickness on one side and a smaller thickness on the other side, the tapered roller is used as the lower straightening roller of the stretch straightener, with the larger diameter end of the tapered roller facing the side with the larger thickness of the strip. When the convex thickness difference is used, for strips with a larger thickness in the middle and a smaller thickness on both sides, the convex roller is used as the lower straightening roller of the stretch straightener. When the strip passes through the stretch straightener, the middle part of the strip in the width direction has a relatively large extension, and the thickness is reduced more. In step three above, the lifting amount of the lower roller of the tension leveler is adjusted according to the transverse difference of the strip. The specific implementation data is as follows: When the thickness difference between the same plate is greater than 0.01 mm and less than 0.015 mm, the lifting amount of the lower straightening roller is 10-12 mm. When the difference in thickness between the same plate is greater than 0.015 mm and less than 0.02 mm, the lifting amount of the lower straightening roller is 12-14 mm. When the thickness difference between the same plate is greater than 0.02 mm and less than 0.025 mm, the lifting amount of the lower straightening roller is 14–16 mm. When the difference between the same plate thickness is greater than 0.025 mm and less than 0.03 mm, the lifting amount of the lower straightening roller is 16-18 mm. In step four above, the specific implementation data for adjusting the elongation rate of the tension leveler based on the transverse difference of the strip is as follows: When the difference in thickness between the same plate is greater than 0.01 mm and less than 0.015 mm, the elongation rate of the tension straightening machine should be set to 0.8%. When the difference in thickness between the same plate is greater than 0.015 mm and less than 0.02 mm, the elongation rate of the tension straightening machine should be set to 1.0%. When the difference in thickness between the same plate is greater than 0.02 mm and less than 0.025 mm, the elongation rate of the tension straightening machine should be set to 1.2%. When the difference between the same plate thickness is greater than 0.025 mm and less than 0.03 mm, the elongation rate of the tension straightening machine should be set to 1.4%. In step five above, due to the high tension of the stretching straightener and the cutting effect of the strip edge, the wear characteristics of the stretching straightener roll are: the wear in the middle section of the roll body is very small, while the wear on the two sides of the roll body corresponding to the strip edge is very fast. The scrapped rolls of the stretching straightener are all caused by the wear on the two sides of the straightener roll corresponding to the strip edge. By selecting an old straightener roll with a wear depth of 8-12mm on the two sides of the roll body corresponding to the strip edge, the strip with a transverse plate difference that is higher in the middle and lower on both sides in the width direction is straightened. The thickness of the strip on both sides is reduced relatively less, while the thickness in the middle is reduced relatively more. In step six above, when the thickness of one side of the hot-rolled strip is greater than that of the other side in the width direction, the lower straightening roller seat is pulled out, and an 8-12mm metal shim is added to the lifting mechanism on the side with greater strip thickness. Then the lower straightening roller seat is sent into the stretch straightener and falls onto the straightening lifting mechanism. When the strip runs, the thickness of the side with greater strip thickness decreases more, and the thickness of the side with less thickness decreases less. In step seven above, a flat roll without wear is used to stretch and straighten the strip under high tension. The thicker parts of the strip in the width direction bear relatively greater tension and elongate more, while the thinner parts bear relatively less tension and elongate less, thereby reducing the transverse thickness difference of the strip. Using the flat roll high elongation method, the elongation of hot-rolled strip can be reduced to 0.016mm.

2. The method for reducing transverse plate difference in hot-rolled steel in an acid-pressing unit according to claim 1, characterized in that: By using tapered rollers, convex rollers, and shims, the transverse thickness difference of hot-rolled strip is reduced to 0.012mm to 0.09mm, thus reducing the transverse thickness difference of the strip. By using worn rollers and flat rollers with high elongation, the transverse thickness difference of hot-rolled strip is reduced to 0.012mm to 0.016mm, providing a high-precision processing environment for subsequent processing of hot-rolled strip. By using worn rollers, the consumption of straightening rollers is reduced by 50%.

3. The method for reducing transverse plate difference in hot-rolled steel in an acid-pressing unit according to claim 1, characterized in that: By utilizing the stretching effect of a stretching straightener, hot-rolled strip steel is subjected to asymmetrical stretching, thereby reducing the transverse thickness difference of the hot-rolled strip steel. After passing through the stretching straightener, the width of the hot-rolled strip steel does not change, only the length increases and the thickness decreases. The increase in strip steel length is equal to the decrease in thickness, so that the strip steel with greater thickness in the width direction is stretched more and the strip steel with less thickness is stretched less, which can reduce the transverse thickness difference of the strip steel.

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