Intelligent roll shifting control method considering hot continuous rolling finish rolling section shape

Abstract

The invention discloses an intelligent roll shifting control method considering hot continuous rolling and finish rolling section shapes. The existing method has the problems that the rolling quantity of strip steel in a roll shifting period is reduced, the roll shifting position change in the last rolling period is small, abrasion is serious, and the cat ear height of a rolled piece is increased. A multifunctional instrument is adopted to detect the local high point value of any side of the section, the local high point measured value is compared with the local high point threshold value, the roll shifting control method is given, homogenization of contact abrasion between the working roll and the strip steel is achieved, the cat-ear-shaped strip steel is delayed or avoided, meanwhile, the roll shifting strategy is changed on line according to the section measured by the multifunctional instrument, and the working efficiency is improved. The purposes of prolonging the rolling kilometers and improving the production efficiency are achieved.

Description

Technical Field

[0001] This invention belongs to the field of rolling mill roll shifting control technology, specifically relating to an intelligent roll shifting control method that takes into account the cross-sectional shape of hot continuous rolling finishing. Background Technology

[0002] Conventional convexity work rolls (such as those with quadratic parabolic curves or sine curves) are common and widely used work roll shapes in hot rolling production, characterized by easy grinding and stable strip shape control. During hot rolling, a wear groove forms between the strip and the work roll after each strip is rolled. The groove is largest at the contact points between the strip ends and the rolls. As the number of strips rolled increases, the groove gradually deepens. In subsequent rolling processes, the grooved areas on the work rolls can form defects such as "cat's ears" and edge waviness on the strip, severely affecting the quality of the strip product and reducing the number of strips rolled in a single roll change cycle.

[0003] Conventional methods for controlling roll slippage in crown control mainly include constant-stroke and variable-stroke methods. Constant-stroke slippage refers to a strategy where the roll slippage limit, step size, and frequency remain constant throughout the entire rolling cycle, changing the slippage direction when the roll reaches its limit position, and repeating this process. Variable-stroke slippage refers to a strategy where the roll slippage limit, step size, and frequency vary. This type of method includes variable-stroke constant-step slippage control and variable-stroke variable-step-step slippage control. Compared to constant-stroke slippage control, variable-stroke slippage control significantly improves roll wear. However, it still has the following drawbacks: (1) Fixed roll shifting mode, unable to change the roll shifting strategy online according to the actual local high point value of the strip; (2) In the current roll shifting control method, the roll shifting step length only changes in the decreasing direction, resulting in a small amount of roll shifting at the end of the rolling process, which is not conducive to uniform wear and will inevitably lead to an increase in local high point values ​​and a decrease in the number of rolled strips. Summary of the Invention

[0004] Technical problem to be solved: In view of the above-mentioned technical problems, the present invention provides an intelligent roll shifting control method that takes into account the cross-sectional shape of hot continuous rolling finishing, which can effectively solve the problems of reduced strip rolling quantity during the roll shifting cycle, small roll shifting position change at the end of rolling, severe wear, and increased cat-ear height of the rolled piece in the above-mentioned roll shifting control method.

[0005] Technical solution: An intelligent roll shifting control method that takes into account the cross-sectional shape of hot continuous rolling mill finishing, using a multi-functional instrument to detect the local high point value on any side of the cross-section. When t < T, S i =S i-1 +d0*L0,S max =S max0 -10; When t≥T, Si =S i-1 -d0*2L0,S max =S max0 ; In the formula, t is the measured value of the local high point, and the unit is μm; T is the local high point threshold, in μm; i represents the number of strips of rolled steel; S i This represents the amount of roll shifting of the current work roll, in mm. S i-1 The amount of roll shifting of the previous work roll, in mm; d0 is the initial direction of the roller shifting; L0 is the initial roller step size, in mm; S0 is the initial amount of roller shifting; S max This represents the maximum roller travel distance, in mm. S max0 This represents the initial limit of the roll shifting, in mm.

[0006] Preferably, when t < T, S i =S i-1 +d0*L0,S max =S max0 -10; if S i ≥S max Then S max '=S max , d'=-d0; if S i ≤-S max Then S max '=-S max , d'=-d0; where S max ' represents the maximum skew travel of the current working roll, and d' represents the skew direction of the current working roll.

[0007] Preferably, when t≥T, S i =S i-1 -d0*2L0,S max =S max0 If S i ≥S max Then S max '=S max , d'=-d0; if S i ≤-S max Then S max '=S max , d'=-d0; where S max ' represents the maximum skew travel of the current working roll, and d' represents the skew direction of the current working roll.

[0008] Preferably, the value of T is 10~20 μm.

[0009] Preferably, d0=1, L0 takes the value of an integer from 5 to 20 mm, and S0=0.

[0010] Preferred, S max The value of S ranges from 0 to 150 mm. max0 It is 100 or 150 mm.

[0011] Furthermore, S max The specific value is half the difference in length between the finishing work roll and the support roll, S max0 The specific value is selected based on the limits of the on-site equipment.

[0012] Beneficial effects: The method of this invention achieves uniform contact wear between the work roll and the strip, delays or avoids the "cat ear" shape of the strip, and at the same time, it changes the roll shifting strategy online based on the measured cross-section of the multi-function instrument, so as to extend the rolling mileage and improve production efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the wear between the rolled piece and the roll in the prior art; Figure 2 This is a schematic diagram of a variable stroke equal step length roller control method in the existing technology; Figure 3 This is a schematic diagram of the roller shifting control method provided by the present invention; Figure 4 Is using Figure 2 The existing roll shifting control method is shown in the local high point diagram of the strip cross section in the later stage; Figure 5 Is using Figure 3 A schematic diagram of the strip cross-section of the present invention's roller shifting control method. Detailed Implementation

[0014] The present invention will be described in detail below with reference to specific embodiments: Currently, wear between the rolled piece and the roll is as follows: Figure 1 As shown in the diagram (all parameters in the diagram represent lengths), a common variable stroke equal step length roller control method is illustrated below. Figure 2 As shown, existing methods all suffer from problems such as reduced strip rolling quantity during the roll shifting cycle, small change in roll position at the end of rolling, severe wear, and increased cat-ear height of the rolled piece.

[0015] like Figure 3As shown, the intelligent roll shifting control method of the present invention, which takes into account the cross-sectional shape of hot strip finishing, starts from the roll shifting zero position in the early stage of the rolling cycle. The initial roll shifting directions of each stand are opposite. Based on the given initial roll shifting step length L0 and initial roll shifting direction d0 of each stand, the roll shifting amount of the next strip is obtained. Each stand reaches the limit roll shifting stroke position S. max or -S max At this time, the direction of the shifting roller is changed to obtain a new shifting roller direction (the current working roller shifting roller direction) d'=-d0, and the shifting roller position of each frame reaches the shifting roller limit position S. max or -S max When changing the extreme position of the shifting roller (the maximum shifting stroke of the current work roll) S max '=S max0 -10.

[0016] When the multi-function instrument detects a local high point value t≥T on any side of the cross-section, the direction of the skewed roller is changed to d'=-d0. Furthermore, if the threshold is exceeded for the first time, the skewed roller step size is changed to 2L0, and so on, until the skewed roller limit is restored to ±S. max0 .

[0017] ① The calculation function for the amount of roller slippage is as follows (local high points are less than the threshold, t < T): S i =S i-1 +d0*L0 ②The calculation function for the amount of roller slippage is as follows (local high points are not less than the threshold, t≥T): S i =S i-1 -d0*2L0 In the formula: i represents the number of strips of rolled steel; S i This represents the amount of roll shifting of the current work roll, in mm. S i-1 The amount of roll shifting of the previous work roll, in mm; t is the measured value of a local high point, in μm; T is the local high point threshold, in μm; Given an initial roll shift S0=0, the maximum roll shift S max The initial roll step length L0 is any integer from 5 to 20 mm, the initial roll direction d0 is 1, the crossover of each frame is opposite, and the local high point threshold T is 10 to 20 μm.

[0018] The specific methods for controlling roller shifting are as follows: When t < T, S i =S i-1 +d0*L0,S max =S max0 -10; If S i ≥S max Then S max '=S max , d'=-d0; If S i ≤-S max Then S max '=-S max , d'=-d0; And so on, and -S max ≤S i ≤S max When the roller is between two extremes, the direction of the roller does not change. When t≥T, S i =S i- 1-d0*2L0,S max =S max0 ; If S i ≥S max Then S max '=S max , d'=-d0; If S i ≤-S max Then S max '=S max , d'=-d0; And so on, and -S max ≤S i ≤S max At this point, the roller direction remains unchanged when it is between two extremes.

[0019] Among them, the maximum roll step length L max The minimum step length L is 20 mm. min The maximum roll travel is 5 mm, the roll step length variation L is any integer within the range of 5~10 mm, and the maximum roll travel S is... max The value ranges from 0 to 150 mm, specifically half the difference in length between the finishing work roll and the support roll; S max0 The value can be 100 or 150 mm, depending on the limits of the equipment on site. Example 1

[0020] When the method of this invention is applied to the rolling of metal sheet and strip, in the hot rolling production, the upper and lower work rolls move in opposite directions by an equal distance for each piece of steel rolled. This movement of the work rolls is called roll shifting.

[0021] The roll shifting control strategy of this invention has the following characteristics: In the early stage of the rolling cycle, the upper and lower work rolls start to shift from the zero position. The initial roll shifting directions of each stand are opposite. Based on the given initial roll shifting step length L0 and initial roll shifting direction d0 of each stand, the roll shifting amount of the next strip is obtained. Each stand reaches the limit roll shifting stroke position S. max or -S max At this time, the direction of the skewed roller is changed to obtain a new skewed roller direction d1=-d0, and the skewed roller position of each frame reaches the skewed roller limit position S. max or -S max When changing the extreme position S' of the skewed roller. max =S max -10. When the multi-function instrument detects a local high point value t≥T on any side of the cross-section, the direction of the skewed roller is changed to d'=-d0. If the threshold is exceeded for the first time, the skewed roller step size is changed to 2L0, and so on, until the skewed roller limit is restored to ±S. max0 .

[0022] Given an initial roll shift S0=0, the maximum roll shift S max =100 mm, the initial roller step length L0 is 10 mm, the initial roller direction d0 is 1, the crossover of each frame is opposite, and the local high point threshold T is 10 μm.

[0023] The roll shifting control method provided by this invention was applied to the 1450 hot rolling mill production of a certain factory, using stands F5-F7. Figure 3 After implementing the roller shifting control method, the wear data of the upper and lower rollers are analyzed. Figure 4 and Figure 5 The comparative analysis revealed that the method of the present invention significantly improves the height of the strip cross-section cat's ear, avoiding the continuous occurrence of local high-point quality defects. It is evident that the roll shifting control method of the present invention is remarkably effective in extending rolling mileage, improving product quality, and increasing production line efficiency in practical applications.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent roll shifting control method for hot continuous rolling and finishing cross-sectional shape, characterized in that: Adopt multifunctional instrument to detect the local high point value of any one side of the section, When t < T, S i = S i-1 + d0*L0, S max = S max0 - 10; S = d0*2L0, t < T i S = d0*2L0, t ≥ T i-1 S = d0*2L0, t < T max S = d0*2L0, t ≥ T max0 S = d0*2L0, t < T In the formula, t is the measured value of the local high point, and the unit is μm; T is the threshold value of the local high point, and the unit is μm; I is the number of rolling strips; S i Roll gap for current block, in mm; S i-1 For the last work roll roll shift, the unit is mm; D0 is the initial roll shifting direction; L0 is the initial roll shifting step length, and the unit is mm; S0 is the initial roll shifting amount; S max MaxRoll is the maximum roll shift in mm. S max0 For initial roll shift limit, in mm.

2. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 1, characterized in that: When t < T, S i = S i-1 + d0*L0, S max = S max0 - 10; if S i ≥ S max , then S max '= S max , d' = -d0; if S i ≤ -S max , then S max ' = -S max , d' = -d0; wherein S max ' is the maximum roll shifting distance of the current block work roll, and d' is the roll shifting direction of the current block work roll.

3. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 1, characterized in that: When t≥T, S i =S i-1 -d0*2L0, S max =S max0 ; if S i ≥S max , S max '=S max , d'=-d0; if S i ≤-S max , S max '=S max , d'=-d0; wherein S max ' is the maximum roll shifting distance of the current block work roll, and d' is the roll shifting direction of the current block work roll.

4. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 1, characterized in that: The value of T is 10-20 μm.

5. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 1, characterized in that: D0=1, the value of L0 is an integer of 5-20 mm, and S0=0.

6. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 1, characterized in that: S max S max0 is 100 or 150 mm.

7. The intelligent roll shifting control method for the cross section shape of the finishing hot rolling according to claim 6, characterized in that: S max The specific value of S is half the difference between the lengths of the finishing work roll and the backup roll, max0 The specific value of S is chosen according to the limits of the on-site equipment.

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