Abnormal vibration control method for six-roller cold continuous rolling mill
By adjusting the mill roll diameter to control mill vibration, the frequent vibration problem of the six-high cold rolling mill was solved, achieving the effects of reducing vibration rate, extending roll life and reducing downtime.
Patent Information
- Application Number
- CN202510707988.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-29
- Publication Date
- 2025-09-16
AI Technical Summary
The six-roller cold rolling mill frequently experiences vertical vibration during long-term operation, resulting in abnormal wear of the rolls, shortened roll changing cycles, and unplanned downtime. Traditional methods cannot effectively solve the systemic vibration caused by wear of the telescopic bar.
By collecting the rolling mill usage data, counting the extension length difference of the rolling mill telescopic cylinder, establishing the rolling mill roll diameter dynamic matching program, adjusting the rolling mill roll diameter to control the rolling mill vibration, ensuring that the extension length of the telescopic cylinder is ≤100mm, and avoiding rolling mill vibration.
The vibration rate of the rolling mill was reduced by 82%, the number of abnormal roll changes was reduced by 40%, the service life of the rolls was extended by 40%, and the downtime was shortened by 55%.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of steel rolling equipment control, and in particular relates to a method for controlling abnormal vibration of a six-roller cold rolling mill. Background Art
[0002] The six-high tandem cold mill is the core equipment for cold-rolled thin plate production. It utilizes a six-high UC (Universal Crown) mill structure, consisting of two pairs of work rolls (WR), intermediate rolls (MR), and backup rolls (BR). It boasts high rigidity (>5000kN / mm) and precise plate shape control (thickness tolerance ±1.5μm). A typical configuration consists of five stands in tandem, capable of rolling automotive and appliance steel sheets with thicknesses ranging from 0.15-3.0mm and widths from 800-2080mm.
[0003] Six-high tandem cold mills frequently experience vertical vibration during long-term operation. Especially when the roll diameter approaches scrap size, the vibration amplitude increases significantly (amplitude frequency >7MP). This vibration causes abnormal roll wear, shortens roll-changing cycles by more than 30%, and triggers unplanned downtime (a single downtime loss of up to four hours).
[0004] At the same time, traditional methods rely on replacing support rollers or adjusting rolling force, but cannot solve the systemic vibration caused by telescopic bar wear (cumulative wear > 2mm / thousand hours). Summary of the Invention
[0005] In order to solve the problem of frequent vertical vibration of a six-roll cold rolling mill during long-term operation, the present invention provides a method for controlling abnormal vibration of a six-roll cold rolling mill, which can control mill vibration, reduce the number of abnormal roll changes, shorten downtime, and reduce abnormal roll losses.
[0006] The technical solution adopted by the abnormal vibration control method of a six-roller cold rolling mill of the present invention is:
[0007] A method for controlling abnormal vibration of a six-high cold rolling mill comprises the following steps:
[0008] S1. Collect the data when the rolling mill is in use and count the cases where the rolling mill begins to vibrate when the extension length difference of the telescopic cylinder of the rolling mill is ≥100mm;
[0009] S2, based on the data in S1, it is concluded that the extension length of the rolling mill telescopic cylinder is inversely proportional to the diameter of the rolling mill roll;
[0010] S3. Establish a dynamic matching program for the rolling mill roll diameter, adjust the rolling mill roll diameter, and make the extension length of the rolling mill telescopic cylinder ≤100mm.
[0011] A further improvement of the technical solution of the present invention is that the difference in the extension length of the telescopic cylinder in step S1 is the distance between the telescopic cylinder and the roller gap in the new roller state minus the distance between the telescopic cylinder and the roller gap in the use state.
[0012] A further improvement of the technical solution of the present invention is that the distance between the telescopic cylinder and the roller gap in the new roller state is WR (MAX) + MR (MAX) + (BR (MAX) / 2) + the distance from the bottom of the bearing box to the middle of the roller neck of the support roller.
[0013] A further improvement of the technical solution of the present invention is that: when in use, the distance between the telescopic cylinder and the roller gap is WR (actual diameter) + MR (actual diameter) + (BR (actual diameter) / 2) + the distance from the bottom of the bearing box to the middle of the roller neck of the support roller.
[0014] A further improvement of the technical solution of the present invention is that in step S1, the extension length of the telescopic cylinder is inversely proportional to the diameter of the rolling mill roll, specifically, the smaller the roll diameter, the longer the extension length of the telescopic rod.
[0015] A further improvement of the technical solution of the present invention is that the dynamic matching procedure of the rolling mill roll diameter in step S3 is specifically as follows:
[0016] By adjusting the diameter of each frame, the control is carried out according to 2490-(WR (actual diameter) + MR (actual diameter) + BR (actual diameter) + the distance from the bottom of the bearing box to the middle of the roll neck of the support roll) ≤ 100mm to avoid mill vibration.
[0017] Due to the adoption of the above technical solution, the technical advancements achieved by the present invention include:
[0018] The present invention can control rolling mill vibration, reducing the vibration incidence by 82%; reduce the number of abnormal roll changes, extending the roll service life by 40%; shorten the downtime, shortening the roll change operation time by 55%; and reduce abnormal roll losses. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific embodiments. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.
[0020] The present invention provides a method for controlling abnormal vibration of a six-high cold rolling mill, comprising the following steps:
[0021] S1. Collect data from the use of the rolling mill and calculate the situation where the rolling mill begins to vibrate when the extension length difference of the rolling mill telescopic cylinder is ≥100 mm; the extension length difference of the telescopic cylinder is the distance between the telescopic cylinder and the roll gap in the new roll state minus the distance between the telescopic cylinder and the roll gap in the use state.
[0022] Specifically, when the roller is in the new state, the distance between the telescopic cylinder and the roller gap is WR (MAX) + MR (MAX) + (BR (MAX) / 2) + the distance from the bottom of the bearing box to the middle of the roller neck of the support roller; when the roller is in use, the distance between the telescopic cylinder and the roller gap is WR (actual diameter) + MR (actual diameter) + (BR (actual diameter) / 2) + the distance from the bottom of the bearing box to the middle of the roller neck of the support roller.
[0023] S2. Based on the data in S1, it is concluded that the extension length of the telescopic cylinder of the rolling mill is inversely proportional to the diameter of the rolling mill roll; that is, the smaller the roll diameter, the longer the extension length of the telescopic rod.
[0024] S3. Establish a dynamic matching program for the rolling mill roll diameter, adjust the rolling mill roll diameter, and make the extension length of the rolling mill telescopic cylinder ≤100mm.
[0025] The above rolling mill roll diameter dynamic matching procedure is specifically as follows:
[0026] By adjusting the diameter of each frame, the control is carried out according to 2490-(WR (actual diameter) + MR (actual diameter) + BR (actual diameter) + the distance from the bottom of the bearing box to the middle of the roll neck of the support roll) ≤ 100mm to avoid mill vibration.
[0027] Example 1
[0028] The use data of the rolls of the rolling mill vibration stand was recorded, and it was found that the rolling mill vibration occurred in the S1-5 stands, and the amplitude was irregular. It can be determined that the rolling mill vibration has no direct connection with any stand. The data is shown in the table below:
[0029]
[0030]
[0031]
[0032]
[0033]
[0034] Tracking roll changes on site revealed that previously non-vibrating stands began vibrating after the mill's work rolls were replaced. A thorough inspection of the historical usage records of both pairs of mill work rolls revealed no anomalies. However, the diameter of the vibrating work rolls was smaller than that of the normal working rolls. The mill's vibration was subsequently determined to be related to the roll diameter within the mill housing. Data collection on the vibrating stands revealed a pattern in which the sum of the roll diameters of the stands experiencing vibration was lower than the sum of the roll necks of the other stands. To verify this, the roll diameter range of the S1 stand was reduced, while that of the other stands was increased. After rolling commenced, the S1 stand began vibrating, while the other stands remained relatively stable.
[0035] Details of roller diameter and amplitude of each stand:
[0036]
[0037]
[0038] By comparing and tracking the amplitude frequency of the rolling mill and the diameter of the roller in use, it was found that the roller diameter is inversely proportional to the vibration amplitude of the rolling mill. The smaller the roller diameter, the larger the amplitude of the rolling mill, and the higher the speed, the larger the amplitude. However, through data tracking, it was found that the speed only affects the amplitude frequency and is not the direct cause of vibration, and the roller cannot directly cause the vibration of the rolling mill. Later, we began to investigate which parameters of the rolling mill would change when the roller diameter becomes smaller, which may cause the vibration. We learned that the rolling mill adjusts the roll gap by using the telescopic bars on both sides of the bottom of the rolling mill to lift the bearing boxes on both sides of the lower support roller to adjust the pressure and thus adjust the roll gap (the longer the roller diameter in the lower half of the rolling mill is), and then we locked the target on the telescopic bar.
[0039] The telescopic rod will wear out after long-term use. Once the telescopic rod is extended too long, it will cause vertical vibration of the rolling mill. The smaller the diameter of the roll in the lower half of the rolling mill, the longer the telescopic rod needs to be extended. This situation corresponds to the situation in the previous investigation that the smaller the roll diameter, the greater the amplitude of the rolling mill.
[0040] After determining the cause of the mill vibration and the starting point of the vibration, a vibration test was carried out on the S4 frame (because the rolling forces of the S1-4 frames are basically the same, but the S4 frame is the fastest speed frame among the S1-4 frames, and the telescopic rod wear is relatively serious. If a suitable solution for the S4 frame is found, the solution can also be adapted to other frames). Since the support rolls are long-cycle rolls and difficult to replace, and the amount of data is small, the working rolls are tracked by increasing them by 5mm each time (if the working roll reaches the upper limit of the diameter, the intermediate roll diameter is increased). At the same time, the crew members informed the extended length of the telescopic rod. After many attempts, the mill roll capacity was finally found to be greater than 1585mm (support roll diameter / 2+working roll diameter+intermediate roll diameter. Since the contact position of the telescopic rod is the support roll bearing box, half of the support roll diameter is taken when measuring the diameter). The mill will not vibrate at this time.
[0041] In this embodiment, the 6-high 5-roll continuous rolling mill is composed of 2 working rolls (WR uses a diameter of 475-425mm), 2 intermediate rolls (MR uses a diameter of 530-480mm), and 2 backup rolls (BR uses a diameter of 1370-1220mm), and the diameter matching difference of the corresponding 2 rolls should be within the corresponding range (the diameter of the lower roll is larger than the diameter of the upper roll, and the diameter difference of the working roll is ≤0.3mm, the diameter difference of the intermediate roll is ≤1mm, and the diameter difference of the backup roll is ≤8mm). The roll capacity in the rolling mill is (WR diameter + MR diameter + BR diameter) * 2. Taking the existing cold rolling as an example, it is (475mm + 530mm + 1370mm) * 2 = 4750mm. Since the roll gap of the cold rolling 6-high continuous rolling mill is adjusted by the telescopic bars on both sides of the lower side of the rolling mill to lift the bearing boxes on both sides of the lower backup roll to adjust the roll gap, it is only necessary to measure the lower half Part of the rolling roller capacity is sufficient. Because the lifting part of the telescopic lever is the lower end surface of the bearings on both sides of the lower support roller, when measuring the extended length of the telescopic lever, it is necessary to calculate the distance from the lower end surface of the support roller bearing to the roller neck plus half of the support roller diameter. When all the rollers are in the new state, the distance between the telescopic lever and the roller gap is WR (MAX) + MR (MAX) + (BR (MAX) / 2) + the distance from the bottom of the bearing box to the middle of the support roller neck, that is: 475mm + 530mm + (1370mm / 2) + 800mm = 2490mm. When all the rollers are close to the scrap diameter, the distance between the telescopic lever and the roller gap is WR (Min) + MR (Min) + (BR (Min) / 2) + the distance from the bottom of the bearing box to the middle of the support roller neck, that is: 425mm + 480mm + (1220mm / 2) + 800) = 2315mm. The difference in the extended length of the telescopic rod (maximum / minimum) is 2490-2315=175 mm, so the extended length of the telescopic rod is inversely proportional to the roller diameter (the smaller the roller diameter, the longer the extended length of the telescopic rod).
[0042] Since the roll gap of the cold rolling six-high continuous rolling mill is adjusted by the telescopic bars on both sides of the bottom of the rolling mill to lift the bearing boxes on both sides of the lower support roll to adjust the pressure and thus adjust the roll gap, the telescopic bars will wear out after long-term use. Once the telescopic bars are extended too long, the rolling mill will vibrate vertically. The longer the telescopic bars need to be extended, the greater the amplitude.
[0043] By collecting usage data, we determined that mill vibration occurs when the extension length difference of the telescopic bars exceeds 100 mm. We then adjusted the diameter of each stand to maintain a value of 2490 mm minus (WR (actual diameter) + MR (actual diameter) + BR (actual diameter) + the distance from the bottom of the bearing box to the center of the backup roll neck) of ≤ 100 mm, thus preventing mill vibration.
[0044] In the above embodiment, the present invention provides a method for controlling abnormal vibration of a six-roll cold rolling mill. The present invention can control the vibration of the rolling mill, reduce the vibration incidence by 82%; reduce the number of abnormal roll changes, and extend the service life of the rolls by 40%; shorten the downtime, and shorten the roll changing operation time by 55%; and reduce abnormal roll losses.
[0045] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Any modifications and improvements made to the technical solution of the present invention by a person of ordinary skill in the art without departing from the design concept of the present invention shall fall within the scope of protection of the present invention. The technical content for which protection is sought in the present invention is fully set forth in the claims.
Claims
1. A method for controlling abnormal vibration of a six-high cold rolling mill, characterized in that: The following steps are included: S1. Collect the data when the rolling mill is in use and count the cases where the rolling mill begins to vibrate when the extension length difference of the telescopic cylinder of the rolling mill is ≥100mm; S2, based on the data in S1, it is concluded that the extension length of the telescopic cylinder of the rolling mill is inversely proportional to the diameter of the rolling mill roll; S3. Establish a dynamic matching program for the rolling mill roll diameter, adjust the rolling mill roll diameter, and make the extension length of the rolling mill telescopic cylinder ≤100mm.
2. The method for controlling abnormal vibration of a six-high cold rolling mill according to claim 1, characterized in that: In step S1 , the difference in the extension length of the telescopic cylinder is the distance between the telescopic cylinder and the roller gap in the new roller state minus the distance between the telescopic cylinder and the roller gap in the use state.
3. The method for controlling abnormal vibration of a six-high cold rolling mill according to claim 2, characterized in that: The distance between the telescopic cylinder and the roll gap in the new roll state is WR (MAX) + MR (MAX) + (BR (MAX) / 2) + the distance from the bottom of the bearing box to the middle of the roll neck of the support roll.
4. The method for controlling abnormal vibration of a six-high cold rolling mill according to claim 2, wherein: The distance between the telescopic cylinder and the roller gap when in use is WR (actual diameter) + MR (actual diameter) + (BR (actual diameter) / 2) + the distance from the bottom of the bearing box to the middle of the roller neck of the support roller.
5. The method for controlling abnormal vibration of a six-high cold rolling mill according to claim 1, characterized in that: In step S1, the extension length of the telescopic cylinder is inversely proportional to the diameter of the rolling mill roll. Specifically, the smaller the roll diameter, the longer the extension length of the telescopic cylinder.
6. The method for controlling abnormal vibration of a six-high cold rolling mill according to claim 1, characterized in that: The specific procedure for the dynamic matching of the rolling mill roll diameter in step S3 is: By adjusting the diameter of each frame, the control is carried out according to 2490-(WR (actual diameter) + MR (actual diameter) + BR (actual diameter) + the distance from the bottom of the bearing box to the middle of the roll neck of the support roll) ≤ 100mm to avoid mill vibration.