Roll shifting method for work roll for improving position of local high point of strip steel

Abstract

The application discloses a work roll shifting method for improving local high point position of strip steel, and relates to the technical field of hot continuous rolling, and comprises the following steps: tracking intermediate roll shifting and cold-rolled ridging in a downstream cold rolling mill, determining the distribution of the local high point position of the cross section of the strip steel prone to ridging when the cold rolling is negatively shifted; determining the relationship between the ridging coil and the local high point position of the cross section of the hot-rolled strip steel; determining the relationship between the local high point of the cross section of the hot-rolled strip steel and the shifting position of the work roll of the hot-rolled strip steel, and subsequently improving the local high point position of the cross section of the strip steel by avoiding the work roll from staying at the shifting position; avoiding the shifting position of the work roll prone to the local high point appearing at the edge of the strip steel, modifying the shifting model data of the work roll; and writing the shifting model data into the shifting model of the roll; the application cooperatively optimizes the shifting position of the work roll, avoids the work roll from staying at the zero position, makes the local high point of the cross section of the strip steel far away from the edge of the strip steel, and further avoids the ridging defects possibly appearing when the cold rolling is negatively shifted.

Description

Technical Field

[0001] This invention relates to the field of hot strip rolling technology, and more specifically to a method for improving the shifting of work rolls at local high points in strip steel. Background Technology

[0002] The thickness of hot-rolled strip in the width direction is also known as the cross-sectional profile of the hot-rolled strip, which directly affects the quality of the cross-sectional profile in downstream processes. For example, if there are local high points in the cross-sectional profile of the hot-rolled silicon steel finished product, cold rolling is prone to rib formation defects, resulting in a reduced cold-rolled yield and ultimately affecting the lamination effect and electromagnetic properties of the silicon steel product. Furthermore, a poor hot-rolled cross-sectional profile can also lead to complex waviness in downstream production processes, affecting the stability of downstream production. To avoid the impact of poor strip cross-sectional profile quality on downstream processes, hot rolling lines may need to be stopped in advance to replace work rolls, affecting hot rolling stability and production efficiency. Therefore, improving the quality of the cross-sectional profile of hot-rolled strip is of great significance to both hot rolling and downstream processes.

[0003] Improving the cross-sectional quality of hot-rolled strip mainly involves reducing the value of local high points and optimizing their location. When the strip width and thickness remain constant within a single hot-rolling plan, the position of the work rolls with CVC roll profiles remains essentially unchanged. This leads to localized wear on the work roll surfaces at the corresponding edges of the strip, resulting in localized high points in the strip's cross-sectional profile. To address these localized high points, designing the downstream F5-F7 stands as concave rolls and employing a reciprocating roll shifting strategy, combined with optimizing the roll shifting model, and ensuring that the upstream F3-F4 stands in the finishing mill also use reciprocating roll shifting, effectively reduces the value of localized high points or prevents their occurrence to some extent. The cold rolling UCMW mill is equipped with tapered intermediate rolls. The position of the intermediate rolls affects the edge reduction of the strip. In order to meet the production requirements of different roll positions in cold rolling, it is necessary to keep the local high points of the hot-rolled strip as far away from the edge as possible to ensure that the local high points of the strip are effectively reduced during the cold rolling process. Therefore, how to improve the position of local high points has become another important measure to reduce the rib formation in cold rolling production. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the position of work roll shifting at local high points in strip steel. By coordinating and optimizing the position of work roll shifting, the method avoids the work roll shifting from staying near the zero position, so that the local high points of the strip cross section are far away from the edge of the strip steel, further avoiding the rib formation defect that may occur during cold rolling negative shifting, and solving the technical problem of rib formation in cold rolling production caused by the existence of local high points on the work roll.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for improving the position of local high points on the work roll includes the following steps:

[0007] Step 1: Track the intermediate roll shifting and cold rolling rib formation of the downstream cold rolling mill to determine the distribution of local high points in the cross section of the strip that are prone to rib formation during cold rolling negative shifting.

[0008] Step 2: Clarify the relationship between the position of the ribbed coil and the local high point position of the cross section of the hot-rolled strip, and determine the optimal area for the position of the local high point position of the cross section of the hot-rolled strip to avoid ribbed formation in the cold-rolled strip;

[0009] Step 3: Clarify the relationship between the local high points in the cross section of the hot-rolled strip and the position of the hot-rolled work roll that has shifted. Subsequently, the position of the local high points in the cross section of the strip will be improved by preventing the work roll from staying at the position of the shifted roll.

[0010] Step 4: Optimize the roll shifting model to avoid the work roll shifting positions that are prone to causing local high points to appear at the edge of the strip, and modify the work roll shifting model data.

[0011] Step 5: Write the above roll shifting model data into the roll shifting model and put it into use during production. The roll shifting model data is input into the rolling model in the form of roll shifting values. During the production process, a specific stand shifts the rolls back and forth according to the set roll shifting values.

[0012] As a further aspect of the present invention, the specific method for determining the distribution of local high points on the cross section of the strip that are prone to rib formation during cold rolling negative lateral movement is as follows: During the cold rolling process, there are negative lateral movement rolls in the intermediate roll of the cold rolling mill. When the negative lateral movement of the intermediate roll reaches the maximum Smax, the tapered area of ​​the intermediate roll shifts into the interior of the strip, weakening its ability to press down on the edge of the strip. By studying the lateral movement of the intermediate roll of the cold rolling mill and the rib formation, the distribution of local high points on the cross section of the strip that are prone to rib formation during cold rolling negative lateral movement can be determined.

[0013] As a further aspect of the present invention, the specific method for determining the optimal area for the local high point position of the cross section of the hot-rolled strip to avoid rib formation in cold-rolled strip is as follows: based on the rib formation feedback from cold rolling, the distance between the local high point and the edge of the hot-rolled strip corresponding to the rib formation coil is checked to determine the relationship between the cold-rolled rib formation and the position of the local high point of the strip, thereby clarifying the optimal area for the local high point position of the cross section of the hot-rolled strip to avoid rib formation in cold-rolled strip.

[0014] As a further aspect of the present invention, the specific method for improving the local high point position of the strip cross section by avoiding the work roll from staying at the position of the shifting roll is as follows: For the rib-forming coil position of the cold rolling feedback, after determining the local high point position of the hot rolling cross section, the change of the work roll shifting roll position during the hot rolling process is checked to clarify the relationship between the work roll shifting roll position and the local high point of the cross section. Subsequently, the local high point position of the strip cross section is improved by avoiding the work roll from staying at the position of the shifting roll.

[0015] The beneficial effects of this invention are:

[0016] (1) By coordinating and optimizing the position of the work roll, the work roll is prevented from staying near the zero position, so that the local high point of the strip cross section is far away from the edge of the strip, thereby avoiding the rib defects that may occur during cold rolling negative skewing.

[0017] (2) When the optimized roll shifting model is used for production, the distance between the local high point of the strip and the edge of the strip increases to more than 150mm, which improves the adaptability of the negative shifting position of the cold rolling intermediate roll, improves the position of the local high point of the cross section profile of the hot rolled strip, increases the distance between the local high point and the edge of the strip, improves the adaptability of the negative shifting of the cold rolling intermediate roll, and helps to reduce the occurrence of cross section rib defects in the cold rolling process. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a flowchart of the method of the present invention;

[0020] Figure 2 This is a schematic diagram of the negative roll of the cold rolling work roll of the present invention;

[0021] Figure 3 This is a schematic diagram comparing the local high points and the ribbed condition of the strip cross section of the present invention;

[0022] Figure 4 This is a schematic diagram of the distribution of F5-F7 rollers before optimization in this invention;

[0023] Figure 5 This is a schematic diagram of the optimized F5-F7 roller distribution of the present invention;

[0024] Figure 6 This is a schematic diagram showing the location of local high points in the cross-section of the hot-rolled strip after optimization according to the present invention. Detailed Implementation

[0025] 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. 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.

[0026] Please see Figure 1 As shown, the present invention provides a method for improving the shifting of work rolls at local high points in strip steel, comprising the following steps:

[0027] Step 1: Track the intermediate roll shifting and rib formation in the downstream cold rolling mill to determine the distribution of local high points on the cross-section of the strip that are prone to rib formation during cold rolling negative shifting. Specifically, during the cold rolling process, there are negative shifting intermediate rolls in the cold rolling mill. When the negative shifting of the intermediate rolls reaches the maximum Smax, the tapered area of ​​the intermediate rolls shifts into the interior of the strip, weakening the ability to press down on the edge of the strip. By studying the intermediate roll shifting and rib formation in the cold rolling mill, the distribution of local high points on the cross-section of the strip that are prone to rib formation during cold rolling negative shifting can be determined.

[0028] Step 2: Clarify the relationship between the ribbed coil and the local high point position of the hot-rolled strip cross section, and determine the optimal area for avoiding ribbed formation in the cold-rolled strip. Specifically, the method for determining the optimal area for avoiding ribbed formation in the cold-rolled strip cross section is as follows: Based on the ribbed formation feedback from the cold rolling mill, check the distance between the corresponding local high point and the edge of the hot-rolled strip corresponding to the ribbed coil, determine the relationship between the cold-rolled ribbed formation and the local high point position of the strip, and thus clarify the optimal area for avoiding ribbed formation in the cold-rolled strip cross section.

[0029] Step 3: Clarify the relationship between the local high points in the cross-section of the hot-rolled strip and the position of the hot-rolled work roll shifting. Subsequently, the position of the local high points in the cross-section of the strip will be improved by avoiding the work roll from staying at the shifting roll position. Specifically, for the rib-forming coil position feedback from cold rolling, after determining the position of the local high points in the hot-rolled cross-section, check the changes in the position of the work roll shifting during the hot rolling process to clarify the relationship between the position of the work roll shifting and the local high points in the cross-section. Subsequently, the position of the local high points in the cross-section of the strip will be improved by avoiding the work roll from staying at the shifting roll position.

[0030] Step 4: Optimize the roll shifting model. Based on the relationship between the local high points in the cross section and the roll shifting position of the work roll, avoid the roll shifting positions of the work roll that are prone to causing local high points to appear at the edge of the strip, and modify the roll shifting model data of the work roll.

[0031] Step 5: Write the above roll shifting model data into the roll shifting model and put it into use during production. The roll shifting model data is input into the rolling model in the form of roll shifting values. During the production process, specific stands shift the rolls back and forth according to the set roll shifting values. In this way, the position of local high points in the cross section of hot-rolled strip can be improved by optimizing the position of the work roll shifting, thereby reducing the occurrence of cold rolling rib defects without affecting the cold rolling roll shifting.

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0033] Track the intermediate roll shifting and cold rolling rib formation in the downstream cold rolling mill. When the intermediate roll shifts negatively, the position of the strip and the roll system is as follows: Figure 2As shown, specifically, from bottom to top, the upper work roll, upper intermediate roll, and upper support roll are arranged above the steel strip, and from top to bottom, the lower work roll, lower intermediate roll, and lower support roll are arranged below the steel strip. The cold rolling process requires that the maximum negative roll displacement (Smax) of the intermediate rolls not exceed 30mm. In a hot rolling plan, three hot-rolled steel coils developed rib formation defects after cold rolling; a retrospective investigation revealed that the cold rolling roll displacement positions were all negative. In this case, adjusting the cold rolling roll displacement value might prevent the rib formation defects after cold rolling, but it would affect the efficiency and rolling stability of the cold rolling mill.

[0034] Clarify the relationship between the ribbed coil and the local high points in the cross-section of the hot-rolled strip. Reverse-check the local high point situation in the cross-section of the hot-rolled strip with the ribbed coil feedback from the cold-rolled processing, and also reverse-check the cross-section situation of the non-ribbed coil in the planned hot-rolled strip corresponding to this ribbed coil, such as... Figure 3 As shown, the distance between the local high point of the hot-rolled cross section of the ribbed steel coil and the edge of the strip is 100mm, while the distance is even greater for the hot-rolled unribbed steel coil, reaching 136mm. The greater distance between the local high point and the edge of the hot-rolled strip cross section means that when there is negative lateral movement in the cold-rolling intermediate rolls, the pressure on the local high point of the strip is greater, which can reduce the occurrence of ribbed defects in cold rolling. Analysis of the local high point situation in the cross section of the hot-rolled strip corresponding to multi-coil cold rolling with ribs shows that the distance between the local high point and the edge of the hot-rolled strip cross section should not be less than 120mm.

[0035] Clarify the relationship between local high points on the cross-section of hot-rolled strip and the positional shifting of the hot-rolling work rolls. Reverse-check the hot-rolling roll shifting of cold-rolled ribbed and unribbed coils. For the three cold-rolled ribbed coils, the corresponding roll shifting on the F5-F7 stands is 10mm, -5mm, and -20mm respectively. For the cold-rolled unribbed coils, the corresponding roll shifting on the F5-F7 stands exceeds 25mm. That is, when the roll shifting on the F5-F7 stands is within 20mm, the high points on the hot-rolled cross-section are close to the edge, making ribbed defects more likely to occur during cold rolling. The corresponding hot-rolling roll shifting positions for cold-rolled coils prone to ribbed defects are as follows: Figure 4 As shown.

[0036] like Figure 5 As shown, when the roll shifting of F5-F7 stands reaches within 20mm at the same time, the local high point of the hot rolling cross section profile is closer to the edge, so the roll shifting model needs to be optimized. In the optimized roll shifting model, the roll shifting of F5-F7 work rolls avoids the 30mm roll shifting range, and the roll shifting of different stands is changed from the synchronous roll shifting of F5 and F7 before optimization to the asynchronous roll shifting mode of three stands.

[0037] like Figure 6 As shown, the model was deployed and tracked the position of local high points in the strip. When using the optimized roll shifting model for production, the distance between the local high points and the edge of the strip increased to over 150mm, improving the adaptability of the negative shifting position of the cold rolling intermediate roll.

[0038] By adopting the above-mentioned roll shifting method, the position of local high points in the cross-sectional profile of hot-rolled strip steel is improved, the distance between local high points and the edge of strip steel is increased, the negative shifting adaptability of intermediate rolls in cold rolling is improved, and the occurrence of cross-sectional rib defects in the cold rolling process is reduced.

[0039] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for improving the shifting of work rolls at local high points in strip steel, characterized in that, Includes the following steps: Step 1: Track the intermediate roll shifting and cold rolling rib formation of the downstream cold rolling mill to determine the distribution of local high points in the cross section of the strip that are prone to rib formation during cold rolling negative shifting. Step 2: Clarify the relationship between the position of the ribbed coil and the local high point position of the cross section of the hot-rolled strip, and determine the optimal area for the position of the local high point position of the cross section of the hot-rolled strip to avoid ribbed formation in the cold-rolled strip; Step 3: Clarify the relationship between the local high points in the cross section of the hot-rolled strip and the position of the hot-rolled work roll that has shifted. Subsequently, the position of the local high points in the cross section of the strip will be improved by preventing the work roll from staying at the position of the shifted roll. Step 4: Optimize the roll shifting model to avoid the work roll shifting positions that are prone to causing local high points to appear at the edge of the strip, and modify the work roll shifting model data. Step 5: Write the above roll shifting model data into the roll shifting model and put it into use during production. The roll shifting model data is input into the rolling model in the form of roll shifting values. During the production process, a specific stand shifts the rolls back and forth according to the set roll shifting values.

2. The method for improving the shifting position of work rolls at local high points in strip steel according to claim 1, characterized in that, The specific method for determining the distribution of local high points on the cross section of strip that are prone to rib formation during cold rolling negative lateral movement is as follows: During the cold rolling process, there are negative lateral movement rolls in the intermediate roll of the cold rolling mill. When the negative lateral movement of the intermediate roll reaches the maximum Smax, the taper area of ​​the intermediate roll shifts into the interior of the strip, weakening its ability to press down on the edge of the strip. By studying the lateral movement of the intermediate roll of the cold rolling mill and the rib formation, the distribution of local high points on the cross section of strip that are prone to rib formation during cold rolling negative lateral movement can be determined.

3. The method for improving the local high point position of the work roll according to claim 2, characterized in that, The specific method for determining the optimal area for local high points in the cross section of hot-rolled strip to avoid rib formation in cold-rolled strip is as follows: Based on the rib formation feedback from cold rolling, check the distance between the local high point and the edge of the hot-rolled strip corresponding to the rib formation coil, determine the relationship between the cold rolling rib formation and the position of the local high point of the strip, and thus clarify the optimal area for local high points in the cross section of hot-rolled strip to avoid rib formation in cold-rolled strip.

4. The method for improving the shifting of work rolls at local high points in strip steel according to claim 3, characterized in that, The specific method to improve the local high point position of the strip cross section by avoiding the work roll from staying at the position of the shifting roll is as follows: For the rib-forming coil position fed back from cold rolling, after determining the local high point position of the hot rolling cross section, check the changes in the position of the work roll shifting roll during the hot rolling process to clarify the relationship between the position of the work roll shifting roll and the local high point of the cross section. Subsequently, the local high point position of the strip cross section is improved by avoiding the work roll from staying at the position of the shifting roll.

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