Control method for solving rigidity of rolling mill in hot rolling process

Abstract

The invention discloses a control method for solving the rigidity of a rolling mill in a hot rolling procedure, which belongs to the technical field of hot rolling and comprises the following steps: regularly detecting arc-shaped base plates on two sides, and replacing the arc-shaped base plates when the abrasion loss of the arc-shaped base plates on two sides exceeds a first abrasion threshold value or a pit greater than a first depth threshold value exists; the lower step pad is detected regularly, and when the abrasion loss of the lower step pad exceeds a second abrasion threshold value or a pit larger than a second depth threshold value exists, the lower step pad is replaced; the upper step pad is detected regularly, and when the abrasion loss of the upper step pad exceeds a third abrasion threshold value or a pit larger than a third depth threshold value exists, the upper step pad is replaced; and the sizes of the working roller housing window and the supporting roller housing window are regularly measured, the sizes of the working roller and the supporting roller bearing box are synchronously measured, and control is conducted according to the standard. The method aims at meeting the requirement for precise control over the rigidity of the rolling mill in the hot rolling process.

Description

Technical Field

[0001] The invention belongs to the technical field of hot rolling, and in particular relates to a control method for solving the rigidity of a rolling mill in a hot rolling process. Background Art

[0002] The stiffness of a rolling mill refers to the ability of the rolling mill to resist the elastic deformation caused by the rolling pressure during the rolling process. This ability is also called the modulus or modulus of the rolling mill. During the rolling process, the rolled piece will undergo plastic deformation under the action of the rolling force, resulting in changes in its thickness and cross-sectional shape. At the same time, the reaction force of the rolled piece will cause a series of parts in the working machine base, such as the rolls, roll bearings, bearing seats, pads, depression cylinders, and archways, to undergo corresponding elastic deformation. Usually, we call the sum of the elastic deformations produced by this series of force-bearing parts the bounce value of the rolling mill, which is also the stiffness of the rolling mill.

[0003] The physical meaning of the rolling mill stiffness coefficient is that it reflects the ability of the rolling mill work stand to resist elastic deformation. Specifically, the rolling pressure required when the rolling mill produces a unit (1mm) elastic deformation is the rolling mill stiffness coefficient. The greater the force, the greater the stiffness coefficient, indicating that the greater the stiffness of the rolling mill, the smaller the elastic deformation of the rolling mill.

[0004] The stiffness of the rolling mill can be obtained by the method of rolling mill bounce calibration. There are two standards for measuring the stiffness of the rolling mill: one is the deviation between the actual measured stiffness and the designed stiffness, and the other is the deviation between the stiffness on the transmission side and the operating side of the rolling mill. In the first case, the deviation between the measured stiffness and the actual stiffness is mainly caused by the wear, aging and excessive gap of the rolling mill parts. In general, the measured stiffness is less than the designed stiffness. The decrease in stiffness will lead to a decrease in the rolling capacity of the rolling mill and a weakened ability to control the thickness of the finished product. In order to ensure the normal operation of the rolling mill, the deviation between the two should not be greater than 5%.

[0005] The second situation, that is, the difference in stiffness between the transmission side and the operating side of the rolling mill, is mainly caused by the different friction between the arches on both sides and the roller bearing seats and various parts, as well as the different wear conditions of the upper and lower step pads on both sides and the arc pads of the support roller bearing seats. The impact of the second deviation of the rolling mill stiffness is usually greater than that of the first deviation. When the stiffness deviation on both sides of the rolling mill is large, in the actual production process, when the rolling mill presses down the system to adjust the roll gap, the two sides are adjusted synchronously, but due to the different stiffness on both sides, the actual effective adjustment amount on both sides is different, which will produce wedge-shaped, wave-shaped and other quality defects, and in severe cases, even lead to production accidents such as rolling breakage and overlapping rolling. Therefore, the deviation value between the two should not be greater than 3%. Summary of the invention

[0006] The present invention aims to solve the technical problems existing in the known technology and provides a control method for solving the rolling mill stiffness in a hot rolling process, which is used for accurately controlling the rolling mill stiffness in the hot rolling process.

[0007] The object of the present invention is to provide a method for controlling the rigidity of a hot rolling mill, comprising:

[0008] Regularly inspect the arc-shaped pads on both sides, and replace the arc-shaped pads when the wear of the arc-shaped pads on both sides exceeds a first wear threshold or there are pits greater than a first depth threshold;

[0009] Regularly inspect the lower step pad, and replace the lower step pad when the wear amount of the lower step pad exceeds a second wear threshold or there is a pit greater than a second depth threshold;

[0010] Regularly inspect the upper step pad, and when the wear amount of the upper step pad exceeds a third wear threshold or there is a pit greater than a third depth threshold, replace the upper step pad;

[0011] Regularly measure the sizes of the working roll arch windows and the backup roll arch windows, and synchronously measure the sizes of the working roll and backup roll bearing boxes, and control them according to standards.

[0012] Preferably, the first wear threshold is 3 mm, and the first depth threshold is 2 mm.

[0013] Preferably, before the support roller is used, foreign matter and oxides on the surface of the arc-shaped pad are cleaned.

[0014] Preferably, the second wear threshold is 5 mm, and the second depth threshold is 3 mm.

[0015] Preferably, before replacing the lower step pad, measure the hardness of the step pads at corresponding positions on both sides. When the hardness difference between the two sides is greater than 2%, make adjustments, otherwise do not make adjustments. Before replacing the support roller, clean the debris on the surface of the lower step pad. After cleaning, apply lubricating grease on the surface of the step pad to prevent oxidation of the step pad.

[0016] Preferably, the third wear threshold is 5 mm, and the third depth threshold is 3 mm.

[0017] Preferably, before replacing the upper step pad, the hardness of the step pads at corresponding positions on both sides is measured, and when the hardness difference between the two sides is greater than 2%, adjustment is performed, otherwise no adjustment is performed.

[0018] The advantages and positive effects of the present invention are:

[0019] The present invention proposes a comprehensive method to accurately control the rigidity of the rolling mill in the hot rolling process from multiple different angles to ensure that the rigidity of the rolling mill can meet the predetermined technical requirements. Specifically, the method includes the following key steps:

[0020] First, by carrying out high-precision inspection of the curved pads, its size and shape data can be accurately obtained. Based on these inspection results, the curved pads of the support rollers can be finely adjusted to ensure that they can provide appropriate support force to achieve the required level of rigidity.

[0021] Secondly, high-precision inspection of the lower step pad and the upper step pad is also crucial. By accurately measuring these two parts, their dimensional deviations can be discovered and adjusted in time to ensure that they can work together during the rolling process and provide stable support, thereby ensuring that the rigidity of the rolling mill meets the design standards.

[0022] Finally, high-precision inspection of the size of the work roll arch window and the support roll arch window is also an indispensable link. By strictly controlling the size of these two windows, it can be ensured that the work roll and the support roll can be installed correctly and maintain the appropriate gap, so as to achieve accurate rolling force transmission during the rolling process, and further ensure that the rolling mill stiffness meets the process requirements.

[0023] In summary, the present invention realizes comprehensive control of the rigidity of the hot rolling process mill through a series of high-precision detection and timely adjustment measures, thereby ensuring the stability of the rolling process and the reliability of product quality. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purpose, control system and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The technical solution of the present invention is:

[0026] A method for controlling the rigidity of a hot rolling mill comprises:

[0027] When adjusting the arc pads of the support rollers, it is necessary to ensure that the wear of the arc pads on both sides does not exceed 3 mm, and no pits deeper than 2 mm are allowed. Before the support rollers are put into use, the surface of the arc pads must be thoroughly cleaned to ensure that there is no foreign matter and oxidation.

[0028] For the lower step pad, the wear should be controlled within 5 mm, and no pits deeper than 3 mm are allowed. Before replacing the lower step pad, the hardness of the step pads at the corresponding positions on both sides needs to be measured. If the hardness difference between the two sides exceeds 2%, corresponding adjustments need to be made; if the hardness difference does not exceed 2%, no adjustments are required. Before replacing the support roller, it is also necessary to thoroughly clean the debris on the surface of the lower step pad, and apply a layer of lubricating grease on the surface of the step pad after cleaning to prevent oxidation of the step pad.

[0029] For the upper step pad, the wear should also be controlled within 5 mm, and no pits deeper than 3 mm are allowed. Before replacing the upper step pad, it is also necessary to measure the hardness of the step pads at the corresponding positions on both sides. If the hardness difference on both sides exceeds 2%, corresponding adjustments are required; if the hardness difference does not exceed 2%, no adjustments are required. Since the installation position of the upper step pad is above the archway, the working environment is relatively good, so there is generally no debris on its surface, so it does not need to be cleaned regularly.

[0030] In order to ensure the normal operation and accuracy of the equipment, it is necessary to regularly measure the dimensions of the working roll arch window and the backup roll arch window. At the same time, it is also necessary to synchronously measure the dimensions of the working roll and backup roll bearing box (with liner) and strictly control them according to the standards listed in the table below.

[0031] Table 1 is the control standard table

[0032] Device Name Control standard (unit: mm) Support roller arch clearance 0.8-1.6 Working roll gap 0.8-2.0

[0033] In rolling mill equipment, the calculation method of the arch gap size is to measure the actual size of the support roll and work roll window and subtract the actual size of the corresponding support roll and work roll bearing box (including its liner) from it. This calculation process is to ensure that the rolls can work smoothly during the operation of the rolling mill and avoid equipment failure caused by dimensional errors.

[0034] In order to ensure the normal operation of the rolling mill, it is very important to regularly check the lubrication of the arch. Lubrication can not only reduce the wear of the equipment, but also improve the rolling efficiency. During the inspection, if the oil hole is found to be blocked, it should be cleared immediately to ensure that the lubricating oil can reach each lubrication point smoothly. In addition, if the rolling mill is not designed with a lubrication system, it is necessary to apply an appropriate amount of butter in the bearing box before the rolls are put on line. Doing so can effectively reduce the friction between the bearing box and the arch, thereby extending the service life of the equipment and ensuring the smooth progress of the rolling process.

[0035] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for controlling the rigidity of a hot rolling mill, characterized in that: include: Regularly inspect the arc-shaped pads on both sides, and replace the arc-shaped pads when the wear of the arc-shaped pads on both sides exceeds a first wear threshold or there are pits greater than a first depth threshold; Regularly inspect the lower step pad, and replace the lower step pad when the wear amount of the lower step pad exceeds a second wear threshold or there is a pit greater than a second depth threshold; Regularly inspect the upper step pad, and when the wear amount of the upper step pad exceeds a third wear threshold or there is a pit greater than a third depth threshold, replace the upper step pad; Regularly measure the sizes of the working roll arch windows and the backup roll arch windows, and synchronously measure the sizes of the working roll and backup roll bearing boxes, and control them according to standards.

2. The method for controlling the rigidity of a hot rolling mill according to claim 1, characterized in that: The first wear threshold is 3 mm, and the first depth threshold is 2 mm.

3. The method for controlling the rigidity of a hot rolling mill according to claim 2, characterized in that: Before using the support roller, clean the foreign matter and oxides on the surface of the arc pad.

4. The method for controlling the rigidity of a hot rolling mill according to claim 1, characterized in that: The second wear threshold is 5 mm, and the second depth threshold is 3 mm.

5. The method for controlling the rigidity of a hot rolling mill according to claim 4, characterized in that: Before replacing the lower step pad, measure the hardness of the step pads at corresponding positions on both sides. When the hardness difference on both sides is greater than 2%, make adjustments, otherwise do not make adjustments. Before replacing the support roller, clean the debris on the surface of the lower step pad. After cleaning, apply lubricating grease on the surface of the step pad to prevent oxidation of the step pad.

6. The method for controlling the rigidity of a hot rolling mill according to claim 1, characterized in that: The third wear threshold is 5 mm, and the third depth threshold is 3 mm.

7. The method for controlling the rigidity of a hot rolling mill according to claim 6, characterized in that: Before replacing the upper step pad, measure the hardness of the step pads at corresponding positions on both sides. When the hardness difference between the two sides is greater than 2%, make adjustments, otherwise do not make adjustments.