Intelligent detection method for the screwdown nut of a rolling mill

Abstract

The embodiment of the application provides a kind of intelligent detection method of mill screwdown nut, it is related to rolling mill technical field.The intelligent detection method of mill screwdown nut includes: the original stiffness coefficient K1 of initial on-line screwdown nut is calculated;In the case where rolling force is greater than 200 tons, the instantaneous stiffness coefficient K of screwdown nut in rolling process is detected;Real-time comparison instantaneous stiffness coefficient K and original stiffness coefficient K1, determine the wear degree of screwdown nut.This method can be without disassembling screwdown screw and screwdown nut, simply and effectively solve the problem that screwdown nut crack and wear cannot be found in time, not only can solve a large number of inspection maintenance time, simultaneously, can effectively avoid the major accident caused by screwdown nut wear too large or crack, without using periodic replacement screwdown nut maintenance mode, avoid the cost waste caused by over maintenance due to periodic replacement.

Description

Technical Field

[0001] This invention relates to the field of steel rolling mill technology, and more specifically, to an intelligent detection method for the pressing nut of a rolling mill. Background Technology

[0002] Rolling mills are used to process slabs into finished product specifications. The electric reduction system, or EGC system, mainly consists of a reduction screw and a reduction nut, used to adjust the mill roll gap. During roll gap adjustment, the reduction screw is rotated via a motor, and its vertical position is adjusted to change the roll gap size for each pass. During steel plate rolling, all rolling forces act on the EGC system. The reduction nut, primarily made of copper, will gradually develop cracks due to wear and fatigue after prolonged use. This reduces roll gap control accuracy and affects steel plate quality. If not replaced in time, the threads of the reduction nut may break, leading to a major equipment safety accident such as roll breakage or damage to the reduction system under thousands of tons of rolling force.

[0003] The EGC system's pressing nut is installed inside the rolling mill stand, making it difficult to accurately and effectively inspect the system's operating status through visual or auditory methods. The installation method of the pressing screw and nut necessitates a cumbersome disassembly and assembly process, requiring approximately 30 hours per session. Inspecting the system by removing it from the line would significantly disrupt production. Furthermore, the pressing nut is expensive; periodic replacement would result in unnecessary maintenance, wasting costs and disrupting production due to repairs.

[0004] Existing diagnostic methods for rolling mill reduction systems, which rely on sudden changes in the reduction displacement sensor, can only reflect problems in the entire reduction system. However, issues such as loose brakes and excessive clearance in the reducer worm gear can also cause the reduction screw to rebound, making it impossible to accurately and directly reflect problems with the reduction nut.

[0005] Therefore, a convenient and effective intelligent detection method for the pressing nuts of rolling mills is needed to accurately determine the operating status of the pressing nuts, guide planned maintenance, save costs, and avoid accidents. Summary of the Invention

[0006] The present invention aims to provide an intelligent detection method for the pressing nuts of a rolling mill, which addresses the technical problem that the pressing nuts of a rolling mill cannot effectively and promptly detect abnormalities such as wear and fatigue cracks during the rolling process, which seriously affects the lean management of equipment and the level of steel plate quality control.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] This invention provides an intelligent detection method for the pressing nuts of a rolling mill. The intelligent detection method for the pressing nuts of a rolling mill includes:

[0009] Calculate the initial stiffness coefficient K1 of the pressed-down nut initially;

[0010] When the rolling force is greater than 200 tons, the instantaneous stiffness coefficient K of the pressed-down nut during the rolling process is detected;

[0011] The wear degree of the pressed nut is determined by comparing the instantaneous stiffness coefficient K with the original stiffness coefficient K1 in real time.

[0012] In an optional embodiment, the original stiffness coefficient K1 is calculated using the following formula:

[0013]

[0014] Where L is the nut height, D is the nut outer diameter, and d is the nut inner diameter. This is the deformation modulus of the copper nut.

[0015] In an optional embodiment, the instantaneous stiffness coefficient K is calculated using the following formula:

[0016] K = X ssegc / xF

[0017] Among them, X ssegc xF represents the actual position detected by the displacement sensor in the EGC system, and xF represents the actual rolling force detected by the pressure head in the EGC system.

[0018] In an optional embodiment, the step of determining the wear degree of the pressed-down nut by comparing the instantaneous stiffness coefficient K with the original stiffness coefficient K1 in real time includes:

[0019] Calculate the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determine the degree of wear of the pressed nut based on K / K1.

[0020] In an optional embodiment, the step of calculating the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determining the degree of wear of the pressed-down nut based on K / K1, includes:

[0021] If 2 ≤ K / K1, it is determined that the pressing nut needs to be replaced, and a red warning is issued, prompting the pressing nut to be replaced within a specified time.

[0022] In an optional embodiment, the step of calculating the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determining the degree of wear of the pressed-down nut based on K / K1, further includes:

[0023] If K / K1≤1.5, and the wear of the pressing nut is normal, a green signal will be issued, indicating that the pressing nut does not need to be replaced.

[0024] If 1.5 < K / K1 < 2, it is determined that the pressure nut is worn, and a yellow warning is issued, indicating that a replacement plan for the pressure nut needs to be prepared.

[0025] In an optional embodiment, the intelligent detection method for the rolling mill's press-down nut further includes:

[0026] Calculate the wear amount dH of the pressed-down nut;

[0027] Determine the degree of wear of the press-down nut based on dH.

[0028] In an optional embodiment, the formula for calculating the wear amount dH is:

[0029] dH=H1-H

[0030] Where H1 is the actual pitch of the threads of the pressing screw and the pressing nut, and H is the pitch between the threads of the pressing screw and the nut.

[0031] In an optional embodiment, the step of determining the degree of wear of the pressure nut based on dH includes:

[0032] If 4.5mm < dH, it is determined that the press-down nut needs to be replaced, and a red warning is issued, prompting the press-down nut to be replaced within a specified time.

[0033] In an optional embodiment, the step of determining the degree of wear of the compression nut based on dH further includes:

[0034] If dH≤1.5mm, and the wear of the press-down nut is normal, a green signal will be issued, indicating that the press-down nut does not need to be replaced.

[0035] If 1.5mm < dH ≤ 3mm, it is determined that the press-down nut needs lubrication, and an orange warning is issued to prompt lubrication.

[0036] If 3mm < dH ≤ 4.5mm, wear is detected in the press-down nut, and a yellow warning is issued, indicating that a replacement plan for the press-down nut needs to be prepared.

[0037] The beneficial effects of the intelligent detection method for the pressing nut of the rolling mill provided in this embodiment of the invention include:

[0038] 1. This method can easily and effectively solve the problem of not being able to detect cracks and wear in the pressing nut in time without removing the pressing screw and pressing nut. It can not only save a lot of inspection and maintenance time, but also effectively avoid major accidents caused by excessive wear or cracks in the pressing nut.

[0039] 2. By adopting this effective inspection method, potential equipment problems can be predicted in advance, and equipment can be repaired in a planned manner according to its actual condition. There is no need to use the maintenance method of periodically replacing the pressure nut, thus avoiding the cost waste caused by over-maintenance due to periodic replacement.

[0040] 3. When the rolling force is greater than 200 tons, the mechanical gap between the rolling mill and the rolls can be fully eliminated. During the rolling process, the screw will not rebound, and the instantaneous stiffness coefficient K of the screw nut can be accurately measured. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A flowchart of an intelligent detection method for the pressing nut of a rolling mill provided in an embodiment of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0047] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0048] Please refer to Figure 1 This embodiment provides an intelligent detection method for the pressing nut of a rolling mill, including the following steps:

[0049] S1: Calculate the initial stiffness coefficient K1 of the pressed-down nut on the initial line.

[0050] During the rolling mill calibration pressing or rolling process, the rolling force acts on the pressing screw and pressing nut, causing them to deform under stress. Since the pressing nut is mainly made of copper and the pressing screw is made of steel, the stiffness coefficient of the pressing nut is much lower than that of the pressing screw. Therefore, under the action of the rolling force, the pressing nut will mainly undergo elastic stretching. After the pressing nut deforms and stretches, the vertical position of the pressing screw changes accordingly. The material and shape design of the pressing nut determine its original stiffness coefficient. The original stiffness coefficient K1 of the pressing nut is calculated by regression. The formula for calculating the original stiffness coefficient K1 is:

[0051]

[0052] Where L is the nut height, D is the nut outer diameter, and d is the nut inner diameter. This is the deformation modulus of the copper nut.

[0053] S2: When the rolling force is greater than 200 tons, the instantaneous stiffness coefficient K of the pressed-down nut is detected during the rolling process.

[0054] After the pressure is released from the upper support roller balance cylinder, the pressing screw, without the balancing force of the upper support roller, falls downwards. Knowing the amount of thread wear on the pressing nut, and with the support roller balance cylinder restoring its balancing force, the tooth gap between the pressing nut and the pressing screw is eliminated under the over-balancing force of the support roller. If the stiffness of the nut does not significantly decrease during the rolling process despite wear, it indicates that the nut can be used safely and normally. However, if the stiffness decreases significantly, it indicates that the nut threads have developed cracks due to prolonged rolling force after wear, and it needs to be replaced promptly.

[0055] Based on the mill calibration and roll gap control principles, a displacement sensor is added to the EGC system within the mill's primary control system to monitor position changes. Under the balancing force of the upper support roll, the mechanical clearance of the upper roll is essentially eliminated. As the mill force increases, the displacement sensor in the EGC system detects the actual position X. ssegc The increase in size indicates that the screw is moving upwards. Based on the position control principle of the EGC system, the encoder controlling the motor speed in the EGC system is checked. The encoder does not detect any rotational speed, indicating that the reducer is not rotating when the brake is engaged. Under conditions where the rolling force is greater than 200 tons and the mechanical clearance between the mill and rolls is fully eliminated, the actual position X detected by the displacement sensor of the EGC system... ssegc Based on the actual rolling force xF detected by the pressure head in the EGC system, the instantaneous stiffness coefficient K of the pressed nut is calculated. The formula for calculating the instantaneous stiffness coefficient K is as follows:

[0056] K = X ssegc / xF

[0057] Among them, X ssegc xF represents the actual position detected by the displacement sensor in the EGC system, and xF represents the actual rolling force detected by the pressure head in the EGC system.

[0058] The actual position X detected by the displacement sensor in the EGC system ssegc The height of the screw drop will decrease, and the distance between the screw and the nut will be the distance between the screw and the nut. By comparing the original design value, the amount of thread wear of the screw nut can be calculated. By analyzing the amount of thread wear, timely warnings can be issued and maintenance can be prompted.

[0059] Each time the rolling mill is calibrated for pressing and rolling steel under load, the mill automatically alarms when the elastic coefficient of the pressing nut and the displacement change of the pressing screw are statistically analyzed under the action of force. The mill displays this coefficient on the main screen of the rolling mill. The alarm will be triggered when the elastic coefficient or displacement change is greater than the preset value.

[0060] S3: Compare the instantaneous stiffness coefficient K with the original stiffness coefficient K1 in real time to determine the wear degree of the pressed nut.

[0061] The instantaneous stiffness coefficient K is compared with the original stiffness coefficient K1 in real time, where K1 = 0.007.

[0062] Specifically, calculate the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determine the wear degree of the pressed nut based on K / K1.

[0063] If K / K1≤1.5, and the wear of the pressing nut is normal, a green signal will be issued, indicating that the pressing nut does not need to be replaced.

[0064] If 1.5 < K / K1 < 2, it is determined that the press-down nut is worn, and a yellow warning is issued, indicating that a replacement plan for the press-down nut needs to be prepared.

[0065] If 2 ≤ K / K1, it is determined that the pressing nut needs to be replaced, and a red warning is issued, prompting the pressing nut to be replaced within a time limit, which may be within one month.

[0066] S4: Calculate the wear amount dH of the press-down nut, and determine the degree of wear of the press-down nut based on dH.

[0067] According to the design, the tooth pitch H between the pressing screw and the nut is 2.2mm. If the pressing nut wears, the tooth pitch H will increase. When replacing the support roller, after the upper support roller balance cylinder is depressurized, the pressing screw, having lost its upward balancing force, will only fall a certain height due to the tooth gap between the pressing screw and the pressing nut. The actual position difference detected by the displacement sensor installed on the pressing screw is the actual tooth pitch H1 between the pressing screw and the pressing nut. The TDC control system automatically records the actual tooth pitch H1 at this time and calculates the wear amount dH of the copper nut. The formula for calculating the wear amount dH is:

[0068] dH=H1-H

[0069] Where H1 is the actual pitch of the threads of the pressing screw and the pressing nut, and H is the pitch between the threads of the pressing screw and the nut.

[0070] If dH≤1.5mm, and the wear of the press-down nut is normal, a green signal will be issued, indicating that the press-down nut does not need to be replaced.

[0071] If 1.5mm < dH ≤ 3mm, it is determined that the press-down nut needs lubrication, and an orange warning is issued to prompt lubrication.

[0072] If 3mm < dH ≤ 4.5mm, wear is detected in the press-down nut, and a yellow warning is issued, indicating that a replacement plan for the press-down nut needs to be prepared.

[0073] If 4.5mm < dH, it is determined that the press-down nut needs to be replaced, and a red warning is issued, prompting the press-down nut to be replaced within a time limit, which may be within one month.

[0074] It is easy to understand that S4 is a supplement to S1-S3, in order to further verify the wear of the pressing nut. S4 is not necessary for the methodology, that is, in some cases, even if dH is greater than a certain value, it does not need to be replaced, and the elasticity of the pressing nut can meet the usage requirements.

[0075] The beneficial effects of the intelligent detection method for the pressing nut of the rolling mill provided in this embodiment include:

[0076] 1. This method can easily and effectively solve the problem of not being able to detect cracks and wear in the pressing nut in time without removing the pressing screw and pressing nut. It can not only save a lot of inspection and maintenance time, but also effectively avoid major accidents caused by excessive wear or cracks in the pressing nut.

[0077] 2. By adopting this effective inspection method, potential equipment problems can be predicted in advance, and equipment can be repaired in a planned manner according to its actual condition. There is no need to use the maintenance method of periodically replacing the pressure nut, thus avoiding the cost waste caused by over-maintenance due to periodic replacement.

[0078] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An intelligent detection method for the pressing nut of a rolling mill, characterized in that, The intelligent detection method for the pressing nuts of the rolling mill includes: Calculate the initial stiffness coefficient K1 of the initially deployed compression nut. The formula for calculating the initial stiffness coefficient K1 is as follows: Where L is the nut height, D is the nut outer diameter, and d is the nut inner diameter. The deformation modulus of the copper nut; When the rolling force is greater than 200 tons, the instantaneous stiffness coefficient K of the pressed-down nut during the rolling process is detected. The formula for calculating the instantaneous stiffness coefficient K is as follows: K=X ssegc / xF Among them, X ssegc xF represents the actual position detected by the displacement sensor in the EGC system, and xF represents the actual rolling force detected by the pressure head in the EGC system. The wear degree of the pressed nut is determined by comparing the instantaneous stiffness coefficient K with the original stiffness coefficient K1 in real time.

2. The intelligent detection method for the pressing nut of the rolling mill according to claim 1, characterized in that, The step of comparing the instantaneous stiffness coefficient K with the original stiffness coefficient K1 in real time to determine the wear degree of the pressed nut includes: Calculate the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determine the wear degree of the pressed nut based on K / K1.

3. The intelligent detection method for the pressing nut of the rolling mill according to claim 2, characterized in that, The step of calculating the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determining the wear degree of the pressing nut based on K / K1, includes: If 2 ≤ K / K1, it is determined that the pressing nut needs to be replaced, and a red warning is issued, prompting the pressing nut to be replaced within a specified time.

4. The intelligent detection method for the pressing nut of the rolling mill according to claim 2, characterized in that, The step of calculating the ratio K / K1 of the instantaneous stiffness coefficient K to the original stiffness coefficient K1, and determining the wear degree of the pressed nut based on K / K1, further includes: If K / K1≤1.5, and the wear of the pressing nut is normal, a green signal will be issued, indicating that the pressing nut does not need to be replaced. If 1.5 < K / K1 < 2, it is determined that the pressure nut is worn, and a yellow warning is issued, indicating that a replacement plan for the pressure nut needs to be prepared.

5. The intelligent detection method for the pressing nut of the rolling mill according to claim 1, characterized in that, The intelligent detection method for the pressing nut of the rolling mill also includes: Calculate the wear amount dH of the pressed-down nut; Determine the degree of wear of the press-down nut based on dH.

6. The intelligent detection method for the pressing nut of the rolling mill according to claim 5, characterized in that, The formula for calculating the wear amount dH is: dH=H1-H Where H1 is the actual pitch of the threads of the pressing screw and the pressing nut, and H is the pitch between the threads of the pressing screw and the nut.

7. The intelligent detection method for the pressing nut of a rolling mill according to claim 5, characterized in that, The step of determining the wear degree of the pressure nut based on dH includes: If 4.5mm < dH, it is determined that the press-down nut needs to be replaced, and a red warning is issued, prompting the press-down nut to be replaced within a specified time.

8. The intelligent detection method for the pressing nut of a rolling mill according to claim 5, characterized in that, The step of determining the wear degree of the pressing nut based on dH further includes: If dH≤1.5mm, and the wear of the press-down nut is normal, a green signal will be issued, indicating that the press-down nut does not need to be replaced. If 1.5mm < dH ≤ 3mm, it is determined that the press-down nut needs lubrication, and an orange warning is issued to prompt lubrication. If 3mm < dH ≤ 4.5mm, wear is detected in the press-down nut, and a yellow warning is issued, indicating that a replacement plan for the press-down nut needs to be prepared.

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