Method for preventing and solving corrugated plate shape defect in steel plate

Abstract

The invention relates to a method for preventing and solving the middle wave plate shape defect of a steel plate, which comprises the following steps of: firstly, judging whether the middle wave plate shape defect of the steel plate occurs under the current rolling pass, and switching the roll bending force under the current rolling pass to a balance mode when the middle wave plate shape defect of the steel plate occurs; and increasing the rolling reduction of the rolled piece under the same rolling pass / reducing the roll bending force under the same rolling pass when the current steel plate enters the rolling operation of the next steel plate with the same specification after the rolling of the steel plate is completed. The mode switching of the roll bending force is carried out in the steel plate rolling process, so that when the medium wave steel plate defect occurs in the steel plate rolling process, the medium wave defect problem can be quickly and effectively solved, meanwhile, the medium wave defect can be prevented in advance when the next steel plate is rolled, the rolling quality of the steel plate is effectively improved, and the production loss is reduced; contract fulfillment is ensured, and production efficiency is improved.

Description

Technical Field

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

[0002] As a common plate shape defect, medium wave steel plate is defined as the phenomenon that the middle part of the steel plate presents wavy undulations due to various factors during the rolling process. Its essence is that the middle thickness is too thinner than the edge.

[0003] The corrugated steel plate not only affects the appearance quality of the product, but also has a serious impact on the subsequent processing and contract delivery, so it has received widespread attention in the industry. In daily production, the uneven distribution of rolling force, uneven temperature distribution of rolled parts, uneven wear of rolls, inappropriate original convexity of rolls, unreasonable roll scheduling and other obvious reasons may cause corrugated steel plates.

[0004] At the same time, there are many invisible reasons, such as large span of steel grades, large jumps in rolling specifications, poor bending roll force model, and imperfect secondary self-learning model, which can all lead to the production of medium-wave steel plates. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preventing and solving corrugated plate defects in steel plates, and to provide an effective solution and prevention method for corrugated plate defects in steel plates from the perspective of process operation and rolling table optimization, thereby ensuring rolling stability and effectively improving product quality.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a method for preventing and solving corrugated plate defects in steel plates, comprising the following steps: S1: Determine whether the steel plate has a middle wave shape defect in the current rolling pass; S2: When the steel plate has the middle wave shape defect, the bending roll force in the current rolling pass is switched to the balance mode; S3: After the steel plate is rolled, when the next steel plate of the same specification is rolled, the reduction amount of the rolled piece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is reduced; In step S2, the bending roll force in the balance mode is the weight of the roll system supporting the working roll plus the force required for the working roll to fit the supporting roll, and basically no bending deflection is generated on the working roll during the rolling process.

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

[0008] Furthermore, when switching the balancing mode, a balancing mode button is pressed manually, and after receiving the information of the manual operation, the rolling mill control system switches the bending roll force to the balancing mode.

[0009] Furthermore, the threshold range of the pressing amount is 0.1-0.5 mm.

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

[0011] Furthermore, the threshold range of the reduction of the bending roll 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: The present invention switches the bending roll force mode and adjusts the pass reduction amount during the steel plate rolling process, so that when a middle wave defect occurs in the steel plate during the rolling process, the problem of the middle wave defect can be quickly and effectively solved, and the middle wave defect can be prevented in advance when the next steel plate is rolled, thereby effectively improving the rolling quality of the steel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings: Figure 1 This is a schematic diagram of the mid-wave steel plate; Figure 2 It is a schematic diagram of the rolling force and bending roll force of the rolled piece; Figure 3 A schematic flow chart of a method for preventing and resolving corrugated plate defects in a steel plate according to the present invention; DETAILED DESCRIPTION

[0014] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] As a common plate defect, corrugated steel plate is defined as the phenomenon that the middle part of the steel plate presents wavy undulations due to various factors during the rolling process. Its essence is that the thickness in the middle is too thin than the edge. Figure 1 shown.

[0016] The present invention provides a method for preventing and resolving corrugated plate defects in steel plates, see Figure 2 and Figure 3 , including the following steps: S1: Determine whether the steel plate has a middle wave shape defect in the current rolling pass; S2: When the steel plate has a corrugated shape defect, the bending roll force in the current rolling pass is switched to the balance mode; S3: After the steel plate has completed the rolling operation, when entering the rolling operation of the next steel plate of the same specification, the reduction amount of the rolled piece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is reduced.

[0017] In the embodiment of the present invention, the bending roll force of the current rolling pass is switched to the bending roll force in the balance mode in the aforementioned step S2. The implementation method is that the operator operates the bending roll force balance button on the control console. After pressing the balance button, the primary control system receives the instruction of the control console, and the rolling mill control bending roll force mode is switched to the balance mode. When the balance system mode is activated, the balance cylinder will be set to a retracted state, and the bending roll force effect disappears, that is, it only plays the role of supporting the weight of the working roll system and fitting the support roll. No bending deflection is generated on the working roll during the rolling process, thereby enabling the defect to be quickly and accurately resolved when the middle wave plate shape defect occurs during the steel plate rolling process.

[0018] At the same time, in the embodiment of the present invention, because the production of medium and thick plates is a batch production mode of similar specifications, after the current steel plate is rolled, when the next steel plate of the same or similar specifications is rolled, in order to prevent the steel plate from having a wave shape, the secondary rolling model will increase the reduction of the pass according to the needs of the operator. In the embodiment of the present invention, the increase in the reduction of the roller is achieved by increasing the rolling force of the pass. When the rolling force increases, the pressure distribution state on the roller during the rolling process will change. The roller is subjected to the reaction force from the rolled piece, that is, the rolling force. This force acts on the entire roller body length direction. Because the roller body is long, the roller will be elastically deformed and deflected. The greater the rolling force, the greater the roller deflection. Generally, there is a positive correlation between the rolling force and the roller deflection, but this relationship is not completely linear. Especially when rolling wide steel, the trend of the roller deflection increasing with the increase of the rolling force will tend to be flat or even decrease after reaching a certain width. This is because the stiffness and strength of the roller limit the unlimited increase of its deflection. The rolling force is further increased by adjusting the amount of reduction, and the shape of the roll is further approached to the negative convexity, thereby effectively preventing the wave problem in steel plate rolling.

[0019] In addition, in the embodiment of the present invention, the phenomenon of corrugated steel plate can be prevented by reducing the corresponding bending roll force in the rolling pass. By reducing the bending roll force, the bending deflection of the rolling roll is increased, and the middle thickness of the steel plate is effectively increased, which effectively plays a role in preventing corrugated steel plate.

[0020] The invention is further described below through specific examples.

[0021] Example 1 In this embodiment, a method for solving the corrugated plate shape defect in steel plate in real time is provided. Specifically, the purpose is to roll a 220mm billet into a 10mm thick steel plate. The rolling mill is a 3800mm four-roll rolling mill, the maximum bending roll force is 8000KN, the balanced bending roll force is 1600KN, and the corrugated plate is generated after the 11th pass of biting steel during the rolling process. The specific rolling pass table is as follows: When it was discovered that a middle wave was generated after biting the steel in the 11th pass, the operator quickly switched the bending roller force (4681.4KN) of the 11th pass to the balanced mode to 1600KN, which quickly and effectively solved the middle wave problem.

[0022] Example 2 In this embodiment, a method for preventing corrugated plate defects in steel plates is provided. For the purpose of clear description, the following two sets of data are used for comparison.

[0023] Improve the previous pass table: Improved pass table: It can be seen from the above data that by adjusting the reduction in 11 passes, the reduction increased from 1.27mm to 1.46mm, and the rolling force increased from 41786KN to 53505KN. The increase in rolling force made the shape of the roll closer to the negative convexity, thereby effectively preventing the wave problem in steel plate rolling.

[0024] To sum up, the present invention provides a method for preventing and solving the wave shape defect in the steel plate. By switching the bending roll force mode and adjusting the rolling reduction amount during the rolling process of the steel plate, when the wave shape defect occurs in the steel plate during the rolling process, the wave shape defect problem can be solved quickly and effectively. At the same time, it can prevent the next similar steel plate from having the wave shape defect during rolling in advance, effectively improve the rolling quality of the steel plate, reduce production losses, and improve production efficiency.

[0025] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preventing and solving corrugated plate defects in steel plates, characterized in that: The steps include: S1: Determine whether the steel plate has a middle wave shape defect in the current rolling pass; S2: When the steel plate has the middle wave shape defect, the bending roll force in the current rolling pass is switched to a balance mode; S3: After the steel plate is rolled, when the next steel plate of the same specification is rolled, the reduction amount of the rolled piece in the same rolling pass is increased and / or the bending roll force in the same rolling pass is reduced; In step S2, the bending roll force in the balance mode is equal to the weight of the working roll system plus the force of the working roll contacting the support roll, and no bending deflection is generated on the working roll during the rolling process.

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

3. A method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that: When switching the balancing mode, a balancing mode button is pressed manually, and after receiving the information of the manual operation, the rolling mill control system switches the bending roll force to the balancing mode.

4. A method for preventing and resolving corrugated plate defects in steel plates according to claim 1, characterized in that: The increase range of the pressing amount is 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 amount is achieved by increasing the rolling force of the rolls.

6. A 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 roller force is 500~2000KN.

Images