A method for improving the control of intermediate waves in the rolling of thin-gauge high-strength pickled sheets
By improving the type of work rolls in the roughing mill and optimizing the proportional crown of the finishing mill, as well as implementing bending roll feedback control, the problem of wavy lines in the middle of high-strength pickled plates was solved, thus improving production stability and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING SHOUGANG CO LTD
- Filing Date
- 2023-03-02
- Publication Date
- 2026-06-05
AI Technical Summary
High-strength pickled steel sheets are prone to intermediate wave problems during the finishing rolling process, resulting in poor production stability and continuity. Moreover, existing technologies cannot effectively control the intermediate wave, which can easily lead to accidents such as strip breakage and tail-wagging.
By changing the roughing mill work roll type to high-speed steel roll, optimizing the load distribution of each pass, optimizing the rolling logic of the finishing mill unit in combination with proportional crown, optimizing the real-time feedback logic of the bending roll, and increasing the adjustment speed of the bending roll of the finishing mill stand, the crown of the intermediate billet is ensured to be within a controllable range.
Effectively control the convexity of the intermediate billet, reduce the waviness phenomenon, improve production stability and efficiency, and prevent strip breakage and other production accidents.
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Figure CN116078826B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of strip steel rolling production technology, and more specifically, to a method for improving the control of intermediate waves during the rolling of thin-gauge high-strength pickled steel sheets. Background Technology
[0002] Hot-rolled pickled steel sheets have the advantage of using heat instead of cold, and are widely used in automobile manufacturing (car chassis, wheels, seats, safety components), home appliance compressors, and mechanical hardware industries. They have become a widely demanded product in various sectors of national economic development. However, due to factors such as high strength, low rolling temperature, large deformation resistance, and poor lateral flow capacity in the mid-to-downstream stands, high-strength pickled steel sheets are prone to intermediate wave problems during the finishing rolling process. In severe cases, this can lead to production accidents such as strip breakage, tailing, and steel piling, greatly affecting the stability and continuity of production, resulting in prominent problems such as reduced production efficiency and increased costs.
[0003] The existing rolling scheme has the following problems:
[0004] 1) Only considers the control of strip wave in the finishing rolling area, without related technologies for controlling the crown of the intermediate billet in the roughing rolling;
[0005] 2) In the finishing mill area, roll shifting is restricted for the intermediate wave generator stand, but as the crown of the incoming intermediate billet changes, the range of roll shifting cannot be corrected in time.
[0006] 3) In the bending roll feedback control system, the control sequence of bending roll force real-time rolling force following control and crown feedback control stops control immediately after the steel is thrown on the upper stand. This results in the inability to compensate for the change in rolling force in the length before the steel is thrown on the upper stand in a timely manner. At the same time, the bending roll force compensation value is small, generally around 5%, which cannot effectively compensate for the change in roll gap crown caused by the increase in rolling force.
[0007] 4) The bending roller intervention speed is 80KN / s. When a sudden large wave shape occurs on site, it cannot provide sufficient compensation quickly, which makes wave shape control increasingly difficult.
[0008] Therefore, there is an urgent need for a method to improve the shortcomings of existing rolling technology. Summary of the Invention
[0009] The embodiments of this application provide a method for improving the control of intermediate waves during the rolling of thin-gauge high-strength pickled steel sheets, in order to solve the problem that intermediate waves are easily generated in the finishing rolling process of high-strength pickled steel sheets.
[0010] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.
[0011] According to a first aspect of the embodiments of this application, a method for improving the control of intermediate waviness during the rolling of thin-gauge high-strength pickled steel sheets is provided, comprising:
[0012] Change the type of work rolls in the roughing mill and optimize the load distribution of each pass in the roughing mill to ensure that the load reduction in the last pass does not exceed the set threshold.
[0013] The rolling logic of the finishing mill unit in rolling strip intermediate billets is optimized based on proportional crown. The proportional crown is the ratio of the thickness of the strip intermediate billet to the crown of the strip intermediate billet.
[0014] Optimize the real-time feedback logic for the bending rolls of the finishing mill;
[0015] Increase the adjustment speed of the bending rolls on the finishing mill stand.
[0016] In some embodiments of this application, based on the foregoing scheme, the change of the work roll type of the roughing mill includes:
[0017] High-speed steel rolls are used as the work rolls of the roughing mill.
[0018] In some embodiments of this application, based on the aforementioned scheme, the roll shape of the work roll of the roughing mill adopts a positive convex shape.
[0019] In some embodiments of this application, based on the aforementioned scheme, the set threshold is 15mm.
[0020] In some embodiments of this application, based on the foregoing scheme, the rolling logic of the finishing mill unit based on proportional crown optimization when rolling strip intermediate billets includes:
[0021] In the finishing mill unit, the first half of the finishing mill rolls the strip intermediate billet to a set proportional crown, and the second half of the finishing mill continues to roll the strip intermediate billet according to the set proportional crown.
[0022] In some embodiments of this application, based on the foregoing scheme, the optimized real-time feedback logic for the bending rolls of the finishing mill includes:
[0023] Extend the ASPC crown feedback control timing and FFC rolling force following control timing of the first half of the finishing mill until the finishing mill stops after the steel is ejected;
[0024] Increase the ASPC adjustment speed and adjustment amount of the first half of the finishing mill stand to ensure that the bending roll force of each finishing mill stand changes within the set range as the rolling force changes.
[0025] In some embodiments of this application, based on the foregoing scheme, the set range is 8%-10%.
[0026] In some embodiments of this application, based on the foregoing solution, the method of increasing the adjustment speed of the bending rolls on the finishing mill stand includes:
[0027] Increase the adjustment speed of the bending rolls on the finishing mill stand to N times the original speed, where N is an integer greater than or equal to 1.
[0028] In some embodiments of this application, based on the foregoing scheme, the roughing mill is a four-high or six-high mill.
[0029] In some embodiments of this application, based on the foregoing scheme, the finishing mill is a four-high or six-high mill.
[0030] The technical solution of this application can quantify the convexity of the intermediate strip billet, ensuring that the convexity of the intermediate strip billet does not exceed 1000um. At the same time, it enhances the control effect of real-time rolling force following control and convexity feedback control of the bending roll force of the first half of the finishing mill unit, and enhances the adjustment speed of increasing and decreasing bending rolls of each stand. In the event of sudden and severe intermediate wave problems, it can quickly improve and eliminate intermediate waves.
[0031] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:
[0033] Figure 1 A schematic flowchart of a method for improving the control of intermediate waves in the rolling of thin-gauge high-strength pickled steel sheets according to an embodiment of this application is shown. Detailed Implementation
[0034] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.
[0035] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.
[0036] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this 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 this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0038] The following detailed description of some embodiments of this application will be provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0039] See Figure 1 The diagram shows a flow chart of a method for improving the control of intermediate waves in the rolling of thin-gauge high-strength pickled steel sheets according to an embodiment of this application.
[0040] like Figure 1 As shown, a method for improving the control of intermediate waviness during the rolling of thin-gauge high-strength pickled steel sheets is presented, which specifically includes steps S100 to S400.
[0041] Step S100: Change the type of work rolls of the roughing mill and optimize the load distribution of each pass of the roughing mill to ensure that the load reduction of the last pass does not exceed the set threshold.
[0042] It should be noted that the intermediate billet, as a transitional product between roughing and finishing in hot strip rolling, typically has its crown set at 1% or 0.5% of its thickness, or obtained by interpolation from the crown interpolation point based on the strip width. Compared to ordinary high-strength steel products, high-strength pickled steel sheets require a balance between surface quality, rolling stability, and production efficiency during hot rolling. Generally, a thin-gauge intermediate billet control strategy is adopted for high-strength pickled steel sheets, with the intermediate billet thickness typically around 30-32 mm. Therefore, the rolling force in each pass of the roughing rolling is generally relatively large.
[0043] It should be noted that in this embodiment, there are two roughing mills, which perform preliminary rolling on the intermediate strip billet.
[0044] It is understandable that during the roughing rolling process, the load of each pass is distributed according to the actual situation, and it is necessary to ensure that the load reduction of the last pass does not exceed the set value. Specifically, in this embodiment, it is necessary to ensure that the load reduction of the last pass does not exceed 15mm, so as to improve the problem of large crown caused by the rolling force of the last pass after the intermediate billet of the strip is thinned.
[0045] In some feasible embodiments, the change of the work roll type of the roughing mill includes:
[0046] High-speed steel rolls are used as the work rolls of the roughing mill.
[0047] Understandably, strip steel is primarily rolled using work rolls on a rolling mill, so the type of work rolls directly impacts the rolling effect. Using high-speed steel rolls can mitigate roll wear issues caused by prolonged running time, thereby increasing the strip steel yield.
[0048] In some feasible embodiments, the work rolls of the roughing mill have a positive convex shape.
[0049] Understandably, setting the roll shape of the work roll to a positive convex shape can further improve the problem of large roll gap convexity caused by rolling force and roll wear.
[0050] In some feasible embodiments, the roughing mill is a four-high or six-high mill.
[0051] Understandably, four-roll or six-roll mills can correspondingly improve rolling efficiency.
[0052] Continue to refer to Figure 1 Step S200: Optimize the rolling logic of the finishing mill unit when rolling the intermediate strip billet based on the proportional crown, wherein the proportional crown is the ratio of the thickness of the intermediate strip billet to the crown of the intermediate strip billet.
[0053] It should be noted that after roughing, the intermediate strip billet enters the finishing rolling area for finishing rolling. The finishing rolling area is equipped with multiple finishing mills, which perform secondary rolling on the intermediate strip billet according to the set rolling logic. During the secondary rolling process, the finishing mills mainly perform fine rolling on the intermediate strip billet to make it roll to the required proportional crown.
[0054] In some feasible embodiments, the rolling logic of the finishing mill unit based on proportional crown optimization when rolling strip intermediate billets includes:
[0055] In the finishing mill unit, the first half of the finishing mill rolls the strip intermediate billet to a set proportional crown, and the second half of the finishing mill continues to roll the strip intermediate billet according to the set proportional crown.
[0056] Understandably, the first half of the rolling mill achieves the change in proportional crown, while the second half of the rolling mill keeps the proportional crown stable.
[0057] It should be noted that for thin-gauge high-strength pickled steel sheets with high alloy content, as the intermediate slab thins, the thickness at the exit of each stand in the finishing mill also decreases. According to the principles of transverse and longitudinal strip flow, when the strip thickness is less than 6mm, the metal mainly flows longitudinally. Therefore, without transverse flow, the change in proportional crown can easily transform into waviness. Thus, as the intermediate slab crown thins, the proportional crown distribution strategy of the finishing mill stands needs to be adjusted accordingly. This aims to ensure that the proportional crown change from the intermediate slab to the target crown is completed in the first half of the finishing mill, preventing the proportional crown change in the second half of the finishing mill from transforming into waviness.
[0058] For example, the finishing area has eight finishing mills, F1-F8. Among them, mills F1-F4 are responsible for the proportional crown change from the intermediate billet crown to the target crown at the finishing mill exit, while mills F4-F7 maintain the same proportional crown, as shown in Table 1.
[0059] Table 1. Changes in proportional convexity
[0060] Rolling mill serial number F1 rolling mill F2 rolling mill F3 Rolling Mill F4 Rolling Mill F5 Rolling Mill F6 rolling mill F7 rolling mill F8 Rolling Mill proportional convexity change 0.55 0.31 0.11 0.03 0 0 0 0
[0061] In some feasible embodiments, the finishing mill is a four-high or six-high mill.
[0062] Understandably, four-roll or six-roll mills can correspondingly improve rolling efficiency.
[0063] Continue to refer to Figure 1 Step S300: Optimize the real-time feedback logic for the bending rolls of the finishing mill.
[0064] It should be noted that roll bending technology refers to the technique of using mechanical force to bend the roll body to control the strip crown (see strip crown) and straightness (see straightness control). In existing roll bending feedback control systems, the roll bending force is controlled in real-time following the rolling force, and the crown feedback control stops immediately after the strip is ejected from the upper stand. This results in the inability to compensate for changes in rolling force along the length before the strip is ejected from the upper stand in a timely manner. Furthermore, the roll bending force compensation value is relatively small, generally around 5%, which cannot effectively compensate for changes in roll gap crown caused by increased rolling force. Therefore, optimizing the real-time feedback logic of the roll bending can effectively improve the control performance.
[0065] In some feasible embodiments, the optimized real-time feedback logic for the bending rolls of the finishing mill includes:
[0066] Extend the ASPC crown feedback control timing and FFC rolling force following control timing of the first half of the finishing mill until the finishing mill stops after the steel is ejected;
[0067] Increase the ASPC adjustment speed and adjustment amount of the first half of the finishing mill stand to ensure that the bending roll force of each finishing mill stand changes within the set range as the rolling force changes.
[0068] It should be noted that in this embodiment, ASPC refers to Automatic Strip Profile Feedback Control; and FFC refers to Force Following Control.
[0069] Specifically, in this embodiment, the range is set to 8%-10%.
[0070] Continue to refer to Figure 1 Step S400: Increase the adjustment speed of the bending rolls on the finishing mill stand.
[0071] It is understandable that as the thickness of the intermediate strip billet decreases, the temperature of the billet entering the finishing mill stand at the tail end becomes lower and lower, causing the rolling force at the tail end to increase in each stand, especially in the upstream stand. If this increase in tail end rolling force cannot be compensated by the bending roll force, it will inevitably cause the strip exit crown to increase, thus causing waviness problems in the downstream stand. Therefore, the effectiveness of bending roll force following the rolling force and crown feedback control is extremely important, and the bending roll force is mainly controlled by the adjustment speed of the bending roll.
[0072] In some feasible embodiments, increasing the adjustment speed of the bending rolls on the finishing mill stand includes:
[0073] Increase the adjustment speed of the bending rolls on the finishing mill stand to N times the original speed, where N is an integer greater than or equal to 1.
[0074] Specifically, in this embodiment, the adjustment speed of the bending roll of the finishing mill stand is increased to three times the original speed to improve the effectiveness and timeliness of the intervention of the bending roll.
[0075] It is understood that in this embodiment, an adjustment button can be set. When the button is pressed, the adjustment speed of the bending roll of the finishing mill stand can be increased by three times. Under normal circumstances, the adjustment speed of the bending roll is 80KN / s. When a sudden and severe wave problem occurs, pressing this adjustment button will increase the adjustment speed of the bending roll to 240KN / s. This speed can quickly provide sufficient compensation and achieve rapid improvement and elimination of the wave.
[0076] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. It should be understood that this application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method for controlling intermediate waviness during the rolling of thin-gauge high-strength pickled steel sheets, characterized in that, include: High-speed steel rolls are used as the work rolls of the roughing mill, and the load distribution of each pass of the roughing mill is optimized to ensure that the load reduction of the last pass does not exceed 15mm. The rolling logic of the finishing mill unit in rolling strip intermediate billets is optimized based on proportional crown. The proportional crown is the ratio of the crown of the strip intermediate billet to the thickness of the strip intermediate billet. Extend the ASPC crown feedback control timing and FFC rolling force following control timing of the first half of the finishing mill until the finishing mill stops after the steel is ejected; increase the ASPC adjustment speed and adjustment amount of the first half of the finishing mill stands to ensure that the bending roll force of each finishing mill stand changes with the rolling force by 8%-10%; Increase the adjustment speed of the bending rolls on the finishing mill stand to three times the original speed; The rolling logic of the finishing mill unit based on proportional crown optimization when rolling strip intermediate billets includes: In the finishing mill unit, the first half of the finishing mill rolls the strip intermediate billet to a set proportional crown, and the second half of the finishing mill continues to roll the strip intermediate billet according to the set proportional crown. The proportional crown change of the second half of the finishing mill is 0.
2. The method according to claim 1, characterized in that, The work rolls of the roughing mill have a positive convex shape.
3. The method according to claim 1, characterized in that, The roughing mill is a four-high or six-high mill.
4. The method according to claim 1, characterized in that, The finishing mill is a four-roll or six-roll mill.