A method for preventing and solving the wave shape defect in a steel plate

Abstract

The present application relates to a method for preventing and solving the wavy plate defects in steel plates, which comprises the following steps: firstly, judging whether the wavy plate defects appear in the current rolling pass of the steel plate or not, and switching the bending roll force in the current rolling pass to the balance mode when the wavy plate defects appear in the steel plate; and secondly, increasing the reduction of the rolled piece in the same rolling pass or reducing the bending roll force in the same rolling pass when the steel plate enters into the rolling operation of the next steel plate with the same specification after the rolling of the current steel plate is completed. Through the mode switching of the bending roll force in the rolling process of the steel plate, the wavy plate defects can be quickly and effectively solved when the wavy plate defects appear in the rolling process of the steel plate, the wavy defects in the rolling of the next steel plate can be prevented in advance, the rolling quality of the steel plate can be effectively improved, the production loss can be reduced, the contract can be ensured, and the production efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of steel plate surface treatment technology in the metallurgical industry, and in particular to a method for preventing and solving corrugated plate defects in steel plates. Background Technology

[0002] Wave-shaped steel plate is a common plate shape defect. It is defined as the phenomenon that the middle part of the steel plate exhibits a wavy undulation due to various factors during the rolling process. Essentially, it is caused by the middle thickness being too thin compared to the edges.

[0003] Wavy steel plates not only affect the appearance quality of products, but also seriously impact subsequent processing and contract delivery, thus attracting widespread attention within the industry. In daily production, obvious causes such as uneven distribution of rolling force, uneven temperature distribution of the rolled piece, uneven wear of the rolls, unsuitable initial roll crown, and unreasonable roll scheduling can all lead to wavy steel plates.

[0004] Meanwhile, there are also many hidden reasons, such as a large range of steel grades, large jumps in rolling specifications, poor bending roll force model, and imperfect secondary self-learning model, all of which can lead to the generation of medium-wave steel plates. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preventing and resolving wavy defects in steel plates. This method provides an effective solution and prevention of wavy defects in steel plates from the perspective of process operation and rolling surface optimization, ensuring rolling stability and effectively improving product quality.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for preventing and resolving corrugated plate defects in steel plates, comprising the following steps: S1: Determine whether the steel plate exhibits a wave-shaped defect in the current rolling pass; S2: When the steel plate exhibits the aforementioned wave-shaped defect, the bending roll force under the current rolling pass is switched to the balance mode; S3: After the steel plate completes the rolling process, when it enters the rolling process of the next steel plate of the same specification, the reduction of the workpiece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is decreased. In step S2, the bending force in the balanced mode is the weight of the supporting work roll system plus the force required for the work roll to adhere to the supporting roll, and basically does not cause bending deflection of the work roll during the rolling process.

[0007] Furthermore, the bending force in the balanced mode is 2.0-2.2 times the weight of the work roll system.

[0008] Furthermore, when switching the balance mode, the balance mode button is pressed manually. After receiving the information from the manual operation, the mill control system switches the bending roll force to the balance mode.

[0009] Furthermore, the threshold range of the compression amount is 0.1~0.5mm.

[0010] Furthermore, the increase in reduction is achieved by increasing the rolling force of each pass.

[0011] Furthermore, the threshold range for reducing the bending roller force is 500~2000KN.

[0012] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention enables the rapid and effective resolution of wavy defects in steel plates during the rolling process by switching the bending roll force mode and adjusting the reduction per pass. It also helps to prevent wavy defects from occurring in the next steel plate during rolling, thereby effectively improving the rolling quality of the steel plates. Attached Figure Description

[0013] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic diagram of a wave-shaped steel plate. Figure 2 This is a schematic diagram showing the interaction between the rolling force and the bending roll force on the rolled piece. Figure 3 This is a flowchart illustrating a method for preventing and resolving corrugated plate defects in steel plates according to the present invention. Detailed Implementation

[0014] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0015] Wavy steel plates, a common plate shape defect, are defined as a phenomenon where the middle of the steel plate exhibits a wavy, undulating shape due to various factors during the rolling process. Essentially, this is caused by the center being excessively thinner than the edges. Figure 1 As shown.

[0016] The present invention provides a method for preventing and resolving corrugated plate defects in steel plates, see reference. Figure 2 and Figure 3 This includes the following steps: S1: Determine whether the steel plate exhibits a wave-shaped defect in the current rolling pass; S2: When a steel plate has a wave-shaped defect, switch the bending roll force under the current rolling pass to the balance mode; S3: After the steel plate completes the rolling process, when it enters the rolling process of the next steel plate of the same specification, the reduction of the workpiece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is decreased.

[0017] In this embodiment of the invention, the bending roll force in step S2 is switched to the balanced mode for the current rolling pass. This is achieved by the operator pressing the bending roll force balance button on the control panel. After pressing the balance button, the primary control system receives the instruction from the control panel, and the mill control bending roll force mode switches to the balanced mode. When the balanced system mode is activated, the balance cylinder is set to the retracted state, and the bending roll force disappears, meaning it only serves to support the weight of the work roll system and adhere to the support roll. During the rolling process, it does not cause bending deflection of the work roll, thus enabling rapid and accurate resolution of wavy plate defects that occur during steel plate rolling.

[0018] Meanwhile, in this embodiment of the invention, since the production of medium and heavy plates follows a batch production mode with similar specifications, when rolling the next steel plate of the same or similar specifications after the current steel plate is rolled, in order to prevent the steel plate from developing a wavy shape, the secondary rolling model will increase the reduction amount of that pass according to the operator's needs. In this embodiment of the invention, the increase in roll reduction is achieved by increasing the rolling force of the pass. Increasing the rolling force changes the pressure distribution on the rolls during the rolling process. The rolls are subjected to a reaction force from the workpiece, i.e., the rolling force. This force acts along the entire length of the roll body. Because the roll body is long, it causes elastic deformation of the roll, resulting in deflection. The greater the rolling force, the greater the roll deflection usually is. Generally, there is a positive correlation between rolling force and roll deflection, but this relationship is not completely linear. Especially when rolling wide strip steel, the trend of increasing roll deflection with increasing rolling force tends to level off or even decrease after reaching a certain width. This is because the rigidity and strength of the roll limit the unlimited increase of its deflection. By adjusting the reduction amount, the rolling force is further increased, and the shape of the roll is brought closer to the negative crown, thereby effectively preventing waviness problems during steel plate rolling.

[0019] Furthermore, in this embodiment of the invention, the phenomenon of wavy steel plates can also be prevented by reducing the bending roll force in the corresponding rolling pass. By reducing the bending roll force, the bending deflection of the rolls is increased, effectively increasing the thickness of the steel plate in the middle, and thus effectively preventing wavy steel plates.

[0020] The following specific examples will further illustrate this point.

[0021] Example 1 This embodiment provides a method for real-time resolution of wavy defects in steel plates. Specifically, it aims to roll a 220mm billet into a 10mm thick steel plate. The rolling mill is a 3800mm four-high mill with a maximum bending roll force of 8000KN and a balance bending roll force of 1600KN. Wavy defects occur after the 11th pass during rolling. The specific rolling pass table is as follows: When a mid-wave was detected after the 11th pass of steel biting, the operator quickly switched the bending roll force (4681.4KN) of the 11th pass to the balance mode to 1600KN, which quickly and effectively solved the mid-wave problem.

[0022] Example 2 In this embodiment, a method for preventing corrugated defects in steel plates is provided. For clarity, the following two sets of data are compared.

[0023] Previous process schedule: Improved pass / fail schedule: As can be seen from the above data, by adjusting the reduction amount in 11 passes, the reduction amount increased from 1.27mm to 1.46mm, and the rolling force increased from 41786KN to 53505KN. The increase in rolling force makes the shape of the rolls move closer to negative crown, thereby effectively preventing waviness problems in steel plate rolling.

[0024] In summary, the method for preventing and resolving wavy defects in steel plates provided by this invention, by switching the bending roll force mode and adjusting the reduction of the rolled piece during the steel plate rolling process, enables the rapid and effective resolution of wavy defects when they occur during rolling. Simultaneously, it can prevent similar steel plates from developing wavy defects during rolling, effectively improving the rolling quality of the steel plates, reducing production losses, and increasing production efficiency.

[0025] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preventing and resolving corrugated plate defects in steel plates, characterized in that, Includes the following steps: S1: Determine whether the steel plate exhibits a wave-shaped defect in the current rolling pass; S2: When the steel plate exhibits the aforementioned wave-shaped defect, the bending roll force under the current rolling pass is switched to the balance mode; S3: After the steel plate completes the rolling process, when it enters the rolling process of the next steel plate of the same specification, the reduction of the workpiece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is decreased. In step S2, under the balancing mode, the balancing cylinder is set to the retracted state, the bending roll force disappears, and the bending roll force is equal to the weight of the working roll system plus the force of the working roll adhering to the support roll, so that the working roll does not bend during the rolling process.

2. The method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that, The bending force in the balanced mode is 2.0-2.2 times the weight of the work roll system.

3. The method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that, When switching the balance mode, the balance mode button is pressed manually. After receiving the information from the manual operation, the mill control system will switch the bending roll force to the balance mode.

4. The method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that, The increase in the compression amount is in the range of 0.1~0.5mm.

5. A method for preventing and resolving corrugated plate defects in steel plates according to claim 4, characterized in that, The increase in the reduction is achieved by increasing the rolling force of the rolls.

6. The method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that, The threshold range for reducing the bending force is 500~2000KN.

Images