Control method for variable-step roll shifting of working roll of finish rolling F7 rack

Abstract

The invention discloses a control method for variable-step-size roll shifting of a working roll of a finish rolling F7 rack, which comprises the following steps: firstly, constructing a flat roll grinding roll shape curve and setting a roll grinding convexity, and then controlling variable-step-size roll shifting of the flat roll; the roll shifting positions of the working rolls are output according to the rolling plan sequence, the roll shifting step length and roll shifting amplitude limiting are restrained in stages by combining different rolling plan block number conditions, reciprocating shifting of the roll shifting positions from the initial position according to a certain rule is achieved, and the function of variable-step-length roll shifting of the working rolls of the finish rolling F7 rack is achieved. Therefore, the whole-plan strip steel width cross free rolling is realized, the direct connection rate of slabs is increased, the charging temperature is increased, and the burnup is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot continuous rolling finishing, and particularly relates to a control method for variable step shifting of the work roll of the finishing F7 stand. Background Art

[0002] Flatness is an important quality index in the strip production process. Due to many influencing factors, complex generation mechanisms, and uncertain, non-linear, and strongly coupled relationships among these influencing factors, flatness control has always been a hot topic and a difficult point in the strip production process. Flatness is not only an important quality index for these high-end strip products, but also the quality of flatness often affects the rolling stability, and thus becomes the key to whether the production can proceed smoothly and whether the product specifications can be broken through. With the increasing market demand for multiple steel grades and specifications, it is becoming increasingly difficult to implement the traditional coffin-shaped rolling plan arrangement principle.

[0003] Currently, in the conventional CVC roll shifting mode, through the existing coffin-shaped plan arrangement principle, the width rebound amount of the strip before and after the rolling plan and the small rolling unit are strictly controlled to ensure the flatness of the strip. This method has great limitations on the rolling plan arrangement. At the same time, it is very difficult to make the rolling unit larger, which has a great impact on the direct connection rate of the slab, and is not conducive to the production capacity of the production line and the flatness quality control. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method for variable step shifting of the work roll of the finishing F7 stand. By outputting the work roll shifting position according to the order of the rolling plan, combining the roll shifting step and the roll shifting limit, the function of variable step shifting of the work roll of the finishing F7 is realized, so as to realize the cross-free rolling of the strip width of the whole plan and improve the direct connection rate of the slab.

[0005] The purpose of the present invention is achieved through the following technical solutions: A control method for variable step shifting of the work roll of the finishing F7 stand, characterized by including the following steps.

[0006] (1) Construct a flat roll grinding roll profile curve.

[0007] (2) Set the roll grinding convexity.

[0008] (3) Flat roll variable step roll shifting control; the roll shifting control process for each rolling plan is as follows: ① The first stage: The roll warming part, ensuring uniform roll warming along the entire length of the roll; using 2 - 4 roll warming materials in the plan for large-stroke CVC shifting; the CVC starting point starts from 0 mm, specifying negative shifting first, and the shifting range is ±A, where A = 80 - 150 mm; the shifting step is a, and a = 40 - 100 mm; ② The second stage: The transition material part, the shifting range is ±B, where B = 60 - 140 mm; the shifting step is b, and b = 40 - 80 mm; ③Third stage: the main material part, the moving range is ±C, where C = 20 - 120 mm; the moving step is c, where c = 10 - 50 mm; ④Fourth stage: starting from the first piece in the first stage, for the remaining main material part after rolling 120 pieces, the moving range is ±D, where D = 20 - 80 mm; the moving step is d, where d = 10 - 30 mm; ⑤Fifth stage: the planned tail part, the moving range is ±F, where F = 10 - 50 mm; the moving step is f, where f = 10 - 20 mm; ⑥Repeat the fifth stage until the entire rolling plan is completed.

[0009] Furthermore, in step (2), through on-site tests and tracking the results, the flat roll crown is gradually refined, and finally a suitable flat roll crown is obtained and set.

[0010] Furthermore, the flat roll grinding roll profile curve of the working roll of the F7 stand grinds the flat roll crown according to -0.075 mm, and the grinding roll profile curve is a quadratic function curve:

[0011] The beneficial effects of the present invention are as follows: By adopting the above control method, by outputting the work roll shifting positions in sequence according to the rolling plan, combining the shifting step and the shifting limit, the function of variable-step shifting of the work roll of the finishing F7 stand is realized, so as to realize the cross-free rolling of the strip width in the whole plan, improve the direct connection rate of the slab, increase the charging temperature, and reduce the fuel consumption. Brief Description of the Drawings

[0012] The present invention is further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the following drawings without creative efforts.

[0013] Figure 1 is the schematic flow chart of the method of the present invention.

[0014] Figure 2 is the schematic diagram of the flat roll grinding roll profile curve of the present invention.

[0015] Figure 3 is the action curve of variable-step shifting of the work roll of the F7 stand of the present invention. Detailed Embodiments

[0016] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0017] As shown in Figure 1 the figure, a control method for variable step shifting of the working roll of the finishing F7 stand includes the following steps: Construct a flat roll grinding roll profile curve.

[0018] By studying the current CVC roll profile situation and combining relevant experiences of other production lines, develop a sine function and a quadratic function roll profile curve. Grind according to the function curve through the roll grinding system, and upload the flat roll identification to the L2 system, and then send it to the shape model.

[0019] The flat roll crown of the F7 working roll is ground according to -0.075 mm, and the grinding roll profile curve is a quadratic function curve. Combining with the roll length of 2550 mm, calculate according to the quadratic function, and the roll profile curve formula is as follows: , where .

[0020] Finally, it is obtained that: , and the specific curve is as shown in Figure 2 the figure.

[0021] Set the roll grinding crown.

[0022] Through experimental tracking, explore the shape section control ability of different flat roll crowns and the matching situation of different flat roll crowns and bending roll forces, and avoid the bending roll force being in the limit position for a long time, which is not conducive to shape control. Combine the on-site experimental tracking situation, gradually refine the flat roll crown, and finally solidify the most suitable flat roll crown.

[0023] (3) Flat roll variable step shifting control. Through on-site tracking and sorting out the settings of the shape model, finally achieve variable step shifting by imitating the way of manually restricting CVC shifting. Measure the CVC shifting position, shifting step and shifting limit of each strip steel, and realize that the limit gradually decreases, and the shifting step gradually decreases in different planned blocks, and finally realize the automatic variable step shifting of the model. The specific shifting control process of each rolling plan is as follows: ① The first stage: the roll warming material part, ensure uniform roll warming along the full length of the roll; use the plan to carry out 2 - 4 pieces of roll warming materials for large stroke CVC shifting; the CVC starting point starts from 0 mm, and specify negative shifting first, with the shifting range of ±A, A = 80 - 150 mm; the shifting step is a, a = 40 - 100 mm; ② The second stage: the transition material part, the shifting range is ±B, B = 60 - 140 mm; the shifting step is b, b = 40 - 80 mm; ③ The third stage: the main material part, the shifting range is ±C, C = 20 - 120 mm; the shifting step is c, c = 10 - 50 mm; ④The fourth stage: Starting from the first piece in the first stage, for the remaining main material part after rolling 120 pieces, the main material part has a shifting range of ±D, where D = 20 - 80 mm; the shifting step is d, where d = 10 - 30 mm; ⑤The fifth stage: For the planned tail part, the shifting range is ±F, where F = 10 - 50 mm; the shifting step is f, where f = 10 - 20 mm; ⑥Repeat the fifth stage until the entire rolling plan is completed.

[0024] The control method of the present invention can be applied to different rolling plans, different numbers of rolling pieces, and strip steels of different steel grades. After using the F7 flat roll on the mill, the shape control of the cross-section is realized, ensuring the safe and stable operation of the F7 flat roll on the mill without failures caused by the flat roll on the mill. At the same time, the quality of the strip cross-section shape during rolling with the flat roll on the mill is monitored to ensure the stable and smooth operation of the F7 flat roll on the mill and the controlled quality.

[0025] The present invention utilizes the characteristics of the flat roll with variable step shifting. The roll wear is uniform, effectively avoiding local wear of the CVC roll profile caused by controlling flatness, providing convenient conditions for cross-free rolling. On the basis of meeting the crown control, by the regular shifting of the work roll, the contact state with the strip is changed, which is equivalent to realizing the function of "roll grinding" online, effectively realizing width-difference-free rolling of the strip, forming free rolling, reducing the probability of the strip edge cutting a certain fixed point of the roll for a long time, reducing the occurrence of box-shaped wear of the roll, and improving the roll utilization rate. During the application process, rolling plan tests with width rebounds of 100 mm, 200 mm, 300 mm, and more than 300 mm can also be carried out, tracking the cross-section quality of the cross-rolled strip and the wear of the roll after leaving the mill, and gradually expanding the test of increasing the width rebound amount to realize cross-free rolling.

[0026] In summary, although the above preferred embodiments are listed in the present invention, it should be noted that although those skilled in the art can make various changes and modifications, unless such changes and modifications deviate from the scope of the present invention, they should all be included in the protection scope of the present invention.

Claims

1. A control method for variable step length and roll shifting of working rolls of a finishing rolling F7 stand, characterized in that: The steps include: (1) Constructing the roller profile curve for flat roller grinding; (2) Setting the roller grinding crown; (3) Flat roll variable step length roll shifting control; the roll shifting control process for each rolling plan is as follows: ① The first stage: hot roller material part, ensure that the roller is hot evenly over the entire length; use 2-4 hot roller materials to carry out CVC large stroke movement; CVC starting point starts from 0mm, specify negative movement first, movement range ±A, A=80-150mm; movement step a, a=40-100mm; ② The second stage: transition material part, the movement range is ±B, B=60-140mm; The step length of the movement is b, b=40-80mm; ③The third stage: For the main material part, the movement range is ±C, C=20-120mm; the movement step is c, c=10-50mm; ④ The fourth stage: starting from the first block of the first stage, the remaining main body material after rolling 120 blocks, the movement range is ±D, D=20-80mm; the movement step is d, d=10-30mm; ⑤ The fifth stage: the tail part of the plan, the movement range is ±F, F=10-50mm; the movement step is f, f=10-20mm; ⑥ Repeat the fifth stage until the entire rolling plan is completed.

2. The control method for variable step length and roll shifting of working rolls of the finishing rolling F7 stand according to claim 1 is characterized in that: In the step (2), firstly, through field tests and tracking the results, the flat roller crown is gradually refined, and finally a suitable flat roller crown is obtained and set.

3. The control method for variable step length and roll shifting of working rolls of the finishing rolling F7 stand according to claim 1 or 2, characterized in that: The flat roll grinding roll profile curve F7 frame working roll flat roll convexity is ground according to -0.075mm, and the grinding roll profile curve is a quadratic function curve: 。

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