Method for avoiding ridging of wide and thin acid pickling strip
By implementing system modeling and production process control on a cold rolling mill, the problem of ridge formation in wide and thin strip steel was solved. By reducing roll gap crown compensation, developing a rolling force bending roll force following program, and adjusting the strip shape target curve, the ridge formation defect was avoided and the surface quality of the strip steel was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHOUGANG JINGTANG IRON & STEEL CO LTD
- Filing Date
- 2023-05-10
- Publication Date
- 2026-05-22
AI Technical Summary
In the production process of cold-rolled wide and thin strip steel, edge defects (bulges, ridges) often occur, which lead to the downgrading or scrapping of cold-rolled sheets and affect the quality of strip steel.
By using a cold continuous rolling mill, the roll gap crown compensation gain is reduced through system model control. A rolling force bending roll force following program is developed. Combined with production process control, the bending roll force of the intermediate roll and work roll is reduced, the target shape curve is adjusted, the coiling tension is reduced, the mismatch between rolling force and bending roll force is avoided, and the axial force caused by poor shape is reduced.
This effectively avoids the surface ridge defects of wide and thin strip steel, improves the surface quality of the strip steel, and ensures the stability of the production process and product quality.
Smart Images
Figure CN116618449B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cold-rolled steel technology, and in particular to a method for preventing ridge formation in acid-rolled wide and thin strip steel. Background Technology
[0002] With economic development, automotive and home appliance users have increasingly higher requirements for the quality of cold-rolled products, particularly regarding the shape and thickness precision of cold-rolled strips. Edge-forming defects, also known as "bulges," "bumps," or "protrusions," frequently occur during the production of wide and thin strips. These defects are caused by the gradual accumulation of surface high points, waviness, uneven performance, or residual stress during the production process of cold-rolled thin strip steel, resulting in strip-shaped bulges and ridges along the length of the strip. This defect can easily lead to the downgrading or even scrapping of cold-rolled sheets, making it a common defect in the production of cold-rolled thin strip steel and affecting its quality. Therefore, we propose a method to avoid edge-forming in acid-rolled wide and thin strip steel. Summary of the Invention
[0003] To achieve the above objectives, the present invention provides a method for avoiding ridge formation in acid-rolled wide and thin strip steel, thereby solving the problems mentioned in the background art.
[0004] A method for avoiding edge formation in pickled and rolled wide and thin strip steel according to the present invention includes the use of a cold rolling mill, which comprises: a first stand S1, a second stand S2, a third stand S3, a fourth stand S4, and a fifth stand S5; each stand includes an upper roll system and a lower roll system arranged opposite to each other, and both the upper roll system and the lower roll system include work rolls, intermediate rolls, and support rolls; wherein, a coiler body is provided at the exit of the fifth stand S5, and a plate roll is provided between the coiler body and the fifth stand S5; the first stand S1, the second stand S2, the third stand S3, the fourth stand S4, and the fifth stand S5 are all provided with work roll bending rolls and intermediate roll bending roll devices;
[0005] The control method for the cold rolling mill includes:
[0006] System model control:
[0007] 1) Reduce the roll gap crown compensation gain by -0.025 using the system model;
[0008] 2) A rolling force and bending roll force following program was developed. The rolling force and bending roll force following program is: △F×△WR / △FF×FFgain=△WR, which avoids the situation where the rolling force and bending roll force are mismatched.
[0009] Production process control:
[0010] 1) Reduce the bending force of the intermediate rolls of the S1-S4 frame by 60-100KN and the bending force of the working rolls of the S1-S4 frame by 80-120KN through production process control;
[0011] 2) Reduce the load distribution of the S4 rack by 10%;
[0012] 3) Reduce the unit tension of the exit winding from 50 MPa to 45 MPa;
[0013] 4) Adjust the target curve of the plate shape according to the requirements of different production lines, and adjust the plate shape curve of thin specifications with a thickness of <0.8mm to edge wave (2-5IU).
[0014] Optionally, in the first step of the system model control, the roll gap crown compensation value is reduced by -0.025, and the initial roll gap crown is reduced from 0.12 to 0.095.
[0015] Optionally, in the second step of the system model control, the rolling force bending roll force following program is as follows: △F×△WR / △FF×FF gain=△WR, where: △F: the difference between the set rolling force and the actual rolling force; △WR / △FF: the bending roll force required for a unit change in rolling force; FF gain: the feedforward gain of the rolling force; △WR: the final work roll bending roll compensation value, which is a real-time variable.
[0016] Optionally, in the first step of the production process control, the initial range of bending force of the working rolls of frames S1-S4 is 150-250KN, and the initial value of bending force of working rolls of S1-S4 is 150KN.
[0017] Optionally, in step 2 of the production process control, the S4 stand is initially loaded at 100% and is adjusted before the wide and thin sheets enter the rolling mill.
[0018] Optionally, in the method, the width range is 1800mm-2100mm and the thickness range is 0.45mm-0.8mm.
[0019] Optionally, in step 4 of the production process control, the strip (13) shape is detected by the shape meter of the S5 stand exit mill, and the shape curve is modified on the human-machine interface.
[0020] Optionally, the front end of the cold rolling mill is provided with a mill inlet tension roll group.
[0021] Optionally, the coiler body is used to coil the rolled strip, the strip shape roller is used to detect the strip shape, and the work roll bending roller and intermediate roll bending roller device are used to adjust the strip shape.
[0022] This invention provides a method to avoid edge formation in pickled and rolled wide and thin strip steel. In the wide and thin strip steel production process of the pickling and rolling line, this method reduces the roll gap crown compensation gain by -0.025 through a system model; and develops a rolling force and bending roll force following program to avoid the mismatch between rolling force and bending roll force.
[0023] By reducing the bending force of the intermediate rolls on stands S1-S4 by 60-100KN and the bending force of the work rolls on stands S1-S4 by 80-120KN in the production process control; reducing the load distribution on stand 4 by 10%; reducing the unit tension of the exit coiling from 50Mpa to 45Mpa; and adjusting the target shape curve according to the requirements of different production lines, adjusting the shape curve of thin strips with a thickness <0.8mm to edge waviness (2-5IU); these measures comprehensively reduce the axial force caused by poor strip shape during strip production, avoid surface edge defects in the wide and thin strip production process of the pickling and rolling line, and improve the surface quality of the strip. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0025] Figure 1 This is a schematic flowchart of a method for avoiding edge formation in acid-rolled wide and thin strip steel according to an embodiment of the present invention.
[0026] Figure 2 This is a schematic diagram of the main equipment structure of the rolling mill in an embodiment of the present invention.
[0027] Figure 3 These are comparison images of the strip surface roughening before and after implementation of the method in this embodiment of the invention.
[0028] In the diagram: 10. Coiler body, 11. Cold continuous rolling mill, 12. Mill inlet tension roll group, 13. Strip steel, 14. Plate roll. Detailed Implementation
[0029] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0030] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.
[0031] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0032] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.
[0033] Example:
[0034] like Figure 1-3 As shown, the present invention is a method for avoiding ridge formation in acid-rolled wide and thin strip steel. Figure 1This is a schematic diagram of a method for avoiding edge formation in acid-rolled wide and thin strip steel according to an embodiment of the present invention. The equipment used includes a cold rolling mill 11, which includes a first stand S1, a second stand S2, a third stand S3, a fourth stand S4, and a fifth stand S5. Each stand includes an upper roll system and a lower roll system arranged opposite to each other. Both the upper roll system and the lower roll system include work rolls, intermediate rolls, and support rolls. A coiler body 10 is provided at the exit of the fifth stand S5. A strip forming roll 14 is provided between the coiler body 10 and the fifth stand S5. The first stand S1, the second stand S2, the third stand S3, the fourth stand S4, and the fifth stand S5 are all equipped with work roll bending rolls and intermediate roll bending roll devices. The coiler body 10 is used to coil the rolled strip steel 13. The strip forming roll 14 is used to detect the strip shape of the strip steel 13. The work roll bending roll and intermediate roll bending roll devices are used to adjust the strip shape of the strip steel 13.
[0035] The control method for the cold rolling mill 11 includes:
[0036] System model control:
[0037] 1. The roll gap crown compensation gain was reduced by -0.025 through the system model;
[0038] 2. A rolling force and bending roll force following program was developed. The rolling force and bending roll force following program is: △F×△WR / △FF×FFgain=△WR, which avoids the situation where the rolling force and bending roll force are mismatched.
[0039] This method for avoiding edge formation in pickled and rolled wide and thin strip steel involves reducing the roll gap crown compensation gain by -0.025 through a system model during the production of wide and thin strip steel on the pickling and rolling line; and developing a rolling force and bending roll force following program to avoid mismatch between rolling force and bending roll force.
[0040] Production process control:
[0041] Step 1: Reduce the bending force of the intermediate rolls in stands S1-S4 by 60-100KN and the bending force of the work rolls in stands S1-S4 by 80-120KN. The initial range of the bending force of the work rolls in stands S1-S4 is 150-250KN, with an initial value of 150KN. By reducing the bending force, the increase in the equivalent crown of the rolls is offset, thereby reducing the actual equivalent crown of the roll gap.
[0042] Step 2: Reduce the load distribution of the S4 stand by 10%. The original load of the S4 stand is 100%. By reducing the reduction rate of the wide and thin S4 stand by 10%, the thermal crown of the S4 stand rolls during production is reduced, and the occurrence of medium waves in the strip after the S4 stand entering the S5 stand is slowed down.
[0043] Step 3: Reduce the exit coiling unit tension from 50 MPa to 45 MPa. Reducing the exit coiling tension decreases the axial force caused by poor strip shape during the coiling process of strip 13, thus slowing down the tendency of strip 13 to develop sharp edges.
[0044] Step 4: Modify the strip shape curve on the human-machine interface. Adjust the target strip shape curve according to the requirements of different production lines. Adjust the strip shape curve of thin specifications with a thickness <0.8mm to edge wave (2-5IU). Set the strip shape control of strip 13 to edge wave mode to change the trend of wide and thin with medium wave.
[0045] By implementing the above measures and steps, the problem of surface ridges in the production of wide and thin strip steel 13 during pickling and rolling was solved, and the surface quality of strip steel 13 was improved.
[0046] In the above scheme, in the first step of system model control, the roll gap crown compensation value is reduced by -0.025, and the initial roll gap crown is reduced from 0.12 to 0.095.
[0047] In the above scheme, in the second step of system model control, the rolling force bending roll force following program is: △F×△WR / △FF×FF gain=△WR, where: △F: the difference between the set rolling force and the actual rolling force; △WR / △FF: the bending roll force required for a unit change in rolling force; FF gain: the feedforward gain of the rolling force; △WR: the final work roll bending roll compensation value, which is a real-time variable.
[0048] In the above scheme, in the first step of production process control, the initial range of bending force of the working rolls of frames S1-S4 is 150-250KN, and the initial value of bending force of working rolls 1-4 is 150KN.
[0049] In the above scheme, in the second step of production process control, the original load of the S4 stand is 100%, and it is adjusted before the wide and thin sheets enter the rolling process.
[0050] In the above scheme, the specific width range is 1800mm-2100mm, and the thickness range is 0.45mm-0.8mm.
[0051] In the above scheme, in the fourth step of production process control, the strip 13 shape is detected by the strip shape instrument of the 5-stand exit rolling mill, and the strip shape curve is modified on the human-machine interface, so that the strip 13 shape can be adjusted accordingly.
[0052] In the above scheme, the front end of the cold rolling mill 11 is provided with a mill inlet tension roller group 12, which can be used to adjust the tension of the strip 13 at the inlet.
[0053] In the above scheme, the coiler body 10 is used to coil the rolled strip steel 13, the strip shape roller 14 is used to detect the strip shape of the strip steel 13, and the work roll bending roller and intermediate roll bending roller device are used to adjust the strip shape of the strip steel 13.
[0054] This method for avoiding edge formation in acid-rolled wide and thin strip steel includes two parts: system model control and production process control. Pre-control is performed according to the system model control settings. Then, the production process control steps are as follows: First, reduce the bending force of the intermediate rolls in stands S1-S4 by 60-100KN and the bending force of the work rolls in stands S1-S4 by 80-120KN; Second, reduce the load distribution of stand S4 by 10%; Third, reduce the exit coiling unit tension from 50MPa to 45MPa; Fourth, adjust the target shape curve according to the requirements of different production lines, adjusting the shape curve of thin specifications with a thickness <0.8mm to edge waviness (2-5IU). By implementing this method, the equivalent crown of the rolls during wide and thin strip steel production is reduced, the waviness tendency during wide and thin strip steel production is decreased, and the coiling tension is reduced.
[0055] In the wide and thin strip production process of the pickling and rolling line, the coiler body 10, cold continuous rolling mill 11, mill inlet tension roll group 12 and strip roll 14 are used to process the strip steel 13. The roll gap crown compensation gain is reduced by -0.025 through the system model. A rolling force bending roll force following program is developed to avoid the mismatch between rolling force and bending roll force. In the production process control, the bending roll force of the intermediate roll of the 1-4 stands is reduced by 60-100KN, the bending roll force of the work roll of the S1-S4 stands is reduced by 80-120KN, the load distribution of the S4 stand is reduced by 10%, the unit tension of the exit coiler is reduced from 50Mpa to 45Mpa, and the target strip shape curve is adjusted according to the requirements of different production lines. The strip shape curve of thin specifications with a thickness <0.8mm is adjusted to edge waves.
[0056] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A method for avoiding ridge formation in pickled and rolled wide and thin strip steel, comprising using a cold continuous rolling mill (11) as the equipment, characterized in that, The cold rolling mill (11) includes: a first stand S1, a second stand S2, a third stand S3, a fourth stand S4 and a fifth stand S5; each stand includes an upper roll system and a lower roll system arranged opposite to each other, and the upper roll system and the lower roll system include a work roll, an intermediate roll and a support roll; wherein, a coiler body (10) is provided at the exit of the fifth stand S5, and a plate roll (14) is provided between the coiler body (10) and the fifth stand S5, and the first stand S1, the second stand S2, the third stand S3, the fourth stand S4 and the fifth stand S5 are all provided with work roll bending roll and intermediate roll bending roll device; The control method of the cold rolling mill (11) includes: System model control: 1) By reducing the roll gap crown compensation gain by -0.025 through the system model, the initial roll gap crown was reduced from 0.12 to 0.095; 2) A rolling force bending roll force following program was developed. The program is: △F×△WR / △FF×FF gain=△WR, which avoids the mismatch between rolling force and bending roll force. Where: △F: the difference between the set rolling force and the actual rolling force; △WR / △FF: the bending roll force required for a unit change in rolling force; FF gain: the feedforward gain of rolling force; △WR: the final work roll bending roll compensation value, which is a real-time variable. Production process control: 1) Reduce the bending force of the intermediate rolls of the S1-S4 frame by 60-100KN and the bending force of the working rolls of the S1-S4 frame by 80-120KN; the initial range of the bending force of the working rolls of the S1-S4 frame is 150-250KN. 2) Reduce the load distribution of the S4 stand by 10%; the original load of the S4 stand is 100%, and this adjustment is made before the wide and thin sheets enter the rolling mill. 3) Reduce the unit tension of the exit winding from 50 MPa to 45 MPa; 4) Adjust the target curve of the plate shape according to the requirements of different production lines, and adjust the plate shape curve of thin specifications with a thickness of <0.8mm to an edge wave of 2-5IU; In the method, the width range is 1800mm-2100mm and the thickness range is 0.45mm-0.8mm.
2. The method for avoiding edge formation in acid-rolled wide and thin strip steel according to claim 1, characterized in that, In the fourth step of the production process control, the strip (13) shape is detected by the shape instrument of the S5 stand exit mill, and the shape curve is modified on the human-machine interface.
3. The method for avoiding edge formation in acid-rolled wide and thin strip steel according to claim 1, characterized in that, The front end of the cold continuous rolling mill (11) is provided with a mill inlet tension roll group (12).