JP2012228730A - Work roll shift rolling method in rolling line of metal strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work roll shift rolling method by which such a problem is solved that reverse crown occurs and the thickness in width ends of a material to be rolled becomes too thin or too thick when the material to be rolled is rolled with a finishing mill or the like on the rolling line of a metal strip in a hot-rolling line or the like.SOLUTION: An evaluation function which is determined by the target value of work roll profile of a work roll 19 shift rolling mill and the predictive calculated value of the work roll profile are calculated for a plurality of evaluation points of the width ends of the material and totalized, and the totalized evaluation function is further totalized for all materials to be planned to be rolled by a rolling cycles. Roll shift position of a rolling order giving the minimum further totalized result is determined as the work roll shift position of the rolling order.

Description

  The present invention is a metal strip rolling line such as a hot rolling line or a cold rolling line, wherein a part or all of the finishing mill is constituted by a work roll shift rolling mill, The present invention relates to a work roll shift rolling method capable of stably and reliably realizing a schedule-free process in the production of a metal strip by solving the problem that the thickness of the width end portion of the material becomes excessively thin or excessive. .

  For example, in a metal strip rolling line such as the hot rolling line 100 shown in FIG. 10, in many cases, the rolling mill constituting the finish rolling mill 18 is partly or entirely a work roll shift as shown in FIG. 11. It consists of a rolling mill. (A) shows a state where the work roll is not shifted (the work roll 19 is shifted in the body length direction), and (b) shows a state where the work roll is shifted. With respect to the center line of the backup roll 20, the work roll shift is performed by shifting the upper and lower work rolls 19 by the same amount, for example, Xmm, in the opposite directions as seen in the body length direction. Is called Xmm. As shown in FIG. 12, there is a cross-roll shift rolling mill that allows the pair of upper and lower work rolls 19 and backup rolls 20 to be crossed and also allows work roll shift.

  Conventionally, as shown in FIG. 13, a rolling mill in which the work roll cannot be shifted in the body length direction has been the mainstream. Also, a set of 60 to 120 rolls 8 to be rolled after the work roll of the rolling mill constituting the finish rolling mill 18 is replaced with a polished one and then replaced with a polished one again. The body is referred to as a rolling cycle. In the past, this rolling cycle was formed to have a rolling forward width configuration called a coffin cycle as shown in FIG.

In this conventional coffin cycle, all the rolled materials inside and outside 800 ° C. made by the slab manufacturing 1, which is the manufacturing process before the hot rolling, are all cooled to room temperature, and then rolled in the rolling order. It was formed on the premise of rearranging.
And, this coffin cycle is to gradually expand the thermal expansion of the work roll in the body length direction by proceeding with rolling one after another from the narrow rolled material to the wide rolled material, After rolling the material to be rolled with the maximum width within the rolling cycle, by rolling the material to be rolled with a narrow width gradually, a rolling forward width configuration that enables rolling at the worn bottom portion of the work roll and It had been. Regarding the thickness, basically, the rolling order thickness configuration is such that the order is from thick to thin.

However, if rolled by a work roll shift rolling mill, as shown in FIG. 14 (b), the rolling forward width configuration is partially reversed, that is, the rolling of the narrow width material is performed after rolling the material with the maximum width. Later, a rolling order width configuration that allows rolling of a wide material, or a rolling order width configuration that continuously rolls a number of materials having almost the same width as shown in FIG. 14 (c). be able to.
This is because, in the slab manufacturing 1, there are cases where different width slabs are manufactured with two lines, and a slab having substantially equal widths is manufactured. When the material to be rolled is conveyed to the hot rolling line 100, a rolling forward width configuration as shown in FIG. 14B is obtained, and in the case of manufacturing a substantially equal width slab, the above-described FIG. 14C is used. This corresponds to the rolling order width configuration as shown.

  Now, instead of the conventional coffin cycle, enabling the rolling without any trouble even in the rolling cycle having the above-mentioned rolling forward width configuration is referred to as schedule-free. As the difference between the average thickness at the width end 25 mm of the material to be rolled and the thickness at the width center, for example, 30 to 120 μm, while ensuring the quality required for the material to be rolled, It is possible to roll high-temperature rolled material as soon as possible after slab production as soon as possible, leading to shortened delivery times and energy costs.

  In the rolling mill in which the work roll cannot be shifted in the body length direction as shown in FIG. 13 before the appearance of the work roll shift rolling mill, after rolling a wide width material after rolling several narrow width materials, In some cases, the material to be rolled was finished in a thickness distribution in the width direction called an inverted crown shown in FIG. The occurrence of the reverse crown was caused by rolling the central width region of the wide material at the thermally expanded portion of the work roll, as shown in FIG. The shape of the trapezoidal work roll longitudinal section shown in FIG. 16A (hereinafter referred to as work roll profile), which is the result of thermal expansion of the work roll, is shown in FIG. As the roll bends, it is deformed, transferred to the material to be rolled, and shaped like an inverted crown shown in FIG.

  Further, in a rolling mill in which the work roll cannot be shifted in the body length direction, when taking a rolling forward width configuration that allows rolling of a wide material after rolling of a narrow material, as shown in FIG. 17 (a), In some cases, the thickness of the width end portion of the material to be rolled, which is rolled at a work roll portion with less wear, becomes too thin. And if it takes the rolling order width | variety structure which rolls many rolled materials of almost the same width continuously, as shown in FIG.17 (b), the work roll part which is rolling the width | variety edge part of a rolled material May be locally worn and transferred to the width end of the next material to be rolled, resulting in a quality defect in which the thickness of the width end of the material to be rolled becomes excessive.

  With the advent of the work roll shift rolling mill, certain upper and lower work rolls are opposite to each other when viewed from the upper and lower work rolls within the interval time after rolling a certain material to start rolling the next material. Shifting the length, it becomes possible to disperse the influence of wear and thermal expansion of the work roll in the width direction of the material to be rolled, the problem of reverse crown shown in FIG. 15, and FIG. The problem of poor quality in which the thickness of the width end portion of the material to be rolled becomes excessively thin or excessive has been considerably solved. However, it has not been completely resolved.

By the way, the material to be rolled is rolled one after another in relation to the problem of the reverse crown and the problem that the thickness of the width end of the material to be rolled becomes excessively thin or excessive. Each time, the problem is how to change the work roll shift position Xmm.
In Patent Document 1 and Patent Document 2, the work roll shift position is expanded by Xmm, 2Xmm, 3Xmm, etc. each time the material to be rolled is rolled one after another, and the end of the machine specifications. The basic premise is a cyclic shift method in which a shift is made after reaching the end of the shift.

Furthermore, in patent document 1, the upper limit is provided in the change amount of the work roll shift position with respect to a certain to-be-rolled material and the following to-be-rolled material, and the plate | board property of a to-be-rolled material does not become unstable.
In both Patent Document 1 and Patent Document 2, an evaluation function determined from a target value and a predicted calculation value of a work roll profile of a work roll shift rolling mill is used to roll the next rolled material up to the rolled material in the middle of the rolling cycle. For subsequent materials to be rolled, the calculation is performed assuming the rolling order work roll shift position, or, further, the evaluation function is summed for the materials to be rolled after the next material to be rolled so that the evaluation function is minimized. The rolling order work roll shift position is determined, and a method of actually rolling each material to be rolled in the rolling cycle is employed.

  In patent document 1, the evaluation function like (1) Formula is taken.

here,
g _{n + 1} (x) is the work roll wear profile,
RB is the length of the work roll,
J is an evaluation function, and the differential value of g _{n + 1} (x), that is, the slope of the wear profile of the work roll is obtained and its variance is taken,
Respectively.

  In Patent Document 2, an evaluation function such as equation (2) is taken.

here,
i is the coordinate in the body length direction of the work roll (1 ≦ i ≦ m),
j is the Workroll shift length (1 ≦ j ≦ n),
f _{now i} is the current value of the target work roll profile,
f _{fut i} is the value of the target work roll profile after rolling N rolled materials,
g _i is the current value of the work roll profile,
d _ij is the predicted change amount of the work roll profile according to the work roll shift length j of the material to be rolled next,
I _{now j} is an evaluation function value of the work roll shift length j of the material to be rolled next with respect to the current value of the work roll profile,
Δh _i is an evaluation function value representing a predicted change amount of a work roll profile from rolling to rolling material to N rolling materials after rolling.
I _{ft j} is an evaluation function value of the work roll shift length j of the material to be rolled next to the work roll profile after rolling the N material to be rolled,
k ₁ and k ₂ are weights of the current value of the work roll profile and the value of the work roll profile after rolling the N workpieces,
I _j is the overall evaluation function of the work roll shift length,
Respectively.

Japanese Patent Laid-Open No. 06-154823 JP-A-63-260615

  However, in the methods such as Patent Document 1 and Patent Document 2, when calculating the evaluation function, the distribution in the length direction of the work roll radius (hereinafter referred to as work roll profile) is calculated over the entire length direction of the work roll. Yes. For this reason, even the work roll part which does not roll a to-be-rolled material will be included in the object of calculation, and since an error may be expanded, the room for the accuracy improvement was left in calculation of an evaluation function.

In addition, Patent Document 1 and Patent Document 2 attempt to determine the work roll shift position when rolling the next material to be rolled after rolling the material to be rolled in the middle of the rolling cycle. There has also been a technical request as to whether or not the work roll shift position in the rolling order can be determined for all the rolled materials scheduled to be rolled in the rolling cycle before rolling the first rolled material.
The present invention has been made to solve such problems as in the prior art, and when rolling a material to be rolled by a finish rolling mill or the like in a metal strip rolling line such as a hot rolling line, , Providing a work roll shift rolling method that can solve the problem that the width end of the material to be rolled becomes too thin or too thick, and makes schedule-free in the production of metal strips stable and reliable The purpose is to achieve this.

That is, the present invention is as follows.
1. When rolling a material to be rolled using a work roll shift rolling mill in a metal strip rolling line,
Assuming the rolling order work roll shift position for all the rolled materials scheduled for rolling in the rolling cycle,
The evaluation function of the following formula (7) determined from the target value and the predicted calculation value of the work roll profile of the work roll shift rolling mill is calculated for the evaluation points at a plurality of width ends of the material to be rolled, and the following formula (8) And totaled as shown in the following formula (9) for all the rolled materials:
Assuming different rolling order work roll shift positions,
The evaluation function of the formula (7) is calculated for evaluation points at a plurality of width end portions of the material to be rolled, and is summed as in the formula (8). Repeat a series of processes to sum up,
A work roll shift rolling method in a metal strip rolling line, wherein a rolling order work roll shift position that minimizes the formula (9) is selected from all rolling order work roll shift positions.

Record

2. When rolling a material to be rolled using a work roll shift rolling mill in a metal strip rolling line,
Assuming the work roll shift position for the first material to be rolled in the rolling cycle, the work roll profile prediction calculation value after rolling is predicted by calculating the evaluation points at the multiple width edges of the material. And
The evaluation function of the following formula (7) determined from the work roll profile target value and the work roll profile prediction calculation value of the work roll shift rolling mill is calculated with respect to the following formula (7) 8) total
For the material to be rolled next to the material to be rolled, the work roll shift position for the previous material to be rolled differs from the work roll shift position by the amount of the work roll shift pitch, and the same work as the material to be rolled. Assuming one or more of the roll shift positions, the work roll profile after rolling is predicted by calculation for each evaluation point, and the evaluation function of the equation (7) is calculated for each evaluation point. A series of processes for determining the work roll shift position that is totaled as in the formula (8) and that minimizes the totaled result for the material to be rolled next, is scheduled to be rolled in the rolling cycle. By repeating for all rolled materials,
The evaluation function of the formula (7) is calculated for the evaluation points at the width end multiple places of the material to be rolled, and the sum is calculated as in the formula (8), and this is further summed for all the materials to be rolled (9 ) Is a work roll shift rolling method in a metal strip rolling line, wherein the roll order work roll shift position is minimized.

Record

3. 1. An upper limit is provided for the work roll shift pitch. Or 2. The work roll shift rolling method described in 1.

  According to the present invention, when rolling a material to be rolled by a finish rolling mill or the like in a metal band rolling line such as a hot rolling line, the problem of reverse crown and the thickness of the width end of the material to be rolled are excessively thin. It is possible to provide a work roll shift rolling method that can eliminate the problem of becoming excessively thick. Thereby, it is possible to stably and reliably realize schedule-free in the production of the metal strip.

Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention Diagram for explaining a hot rolling line suitable for applying the present invention Diagram for explaining work roll shift rolling mill Diagram for explaining cross roll shift rolling mill Diagram for explaining a conventional rolling mill Diagram for explaining the prior art Diagram for explaining reverse crown Diagram for explaining cause of reverse crown Diagram for explaining poor quality in which the thickness of the width end of the material to be rolled becomes excessively thin or excessive

One embodiment of the present invention will be described below. The following processing is preferably performed by calculation in the process computer 70, taking the case of the hot rolling line 100 shown in FIG. 10 as an example.
In the present invention, for all materials to be rolled in the rolling cycle, assuming the rolling order work roll shift position, the evaluation function determined from the target value and the predicted calculation value of the work roll profile of the work roll shift rolling mill, Calculating the evaluation points at the multiple width ends of the material to be rolled, further summing up all the rolled materials, assuming different rolling order work roll shift positions, Rolling order work that calculates the evaluation points of the points and repeats a series of processes for totalizing all the rolled materials, and the total result is minimized from all the rolling order work roll shift positions. Select the roll shift position.

As an assumption of the rolling order work roll shift position, there is a method of selecting one rolling order work roll shift position from among all rolling order work roll shift positions using, for example, a random number table.
Although an evaluation function is determined from a work roll profile target value and a work roll profile prediction calculation value, in the present invention, as shown in FIG. In order to calculate, as shown in FIG. 1 (b), the target value and the predicted calculation are compared with the conventional methods such as Patent Document 1 and Patent Document 2 in which the work roll profile is calculated over the entire length of the work roll. It is difficult to increase the error of the value, and moreover, it is easy to cause the problem of reverse crown and the problem that the thickness of the width end of the material to be rolled becomes too thin or too thick. Since the evaluation function is calculated and summed for the evaluation points of the points, the problem of reverse crown and the problem that the width end of the rolled material becomes too thin or too thick can be prevented more effectively. Can do.

  In addition, the present invention does not intend to determine the work roll shift position when rolling the next rolled material after rolling up to the rolled material in the middle of the rolling cycle, but the first rolled material in the rolling cycle. Before rolling the material, the rolling order work roll shift position can be determined for all the rolled material scheduled to be rolled in the rolling cycle, so the problem of reverse crown and the thickness of the width end of the rolled material are too thin. There is also an aspect that can effectively prevent the problem of becoming excessively thick.

  Evaluation points are, for example, A (25 mm from the widest end), B (50 mm), C (75 mm), D (100 mm), E (150 mm), F (200 mm) in FIG. ) And the like, and the work roll profiles are assumed to be on the driven side (drive side DS) and driven side (work side WS) on the material to be rolled. The difference between the average of the work roll radii at the work roll points in contact with each of the points A to F and the work roll radius at the center of the length of the work roll is calculated as shown in Equation (3), and the total is calculated for the upper and lower work rolls. However, specific numerical values for the distances from the widest end of the evaluation points A to F are merely examples, and the present invention is not limited to these examples.

  For example, the evaluation function predicts and calculates the thermal expansion shown in FIG. 2 (a) as shown in Equation (4), and predicts and calculates the wear shown in FIG. 2 (b) as shown in Equation (5). Based on the predicted calculation value calculated as in the equation (6) for the work roll profile obtained by summing up the values, the equation is calculated as in the equation (7).

Note that the weighting coefficient _ck in the equation (7) may be determined according to the width change from the previous rolled material to the next rolled material as shown in Table 1, for example.

An example of the processing flow of the work roll shift position determination method of the present invention is shown in FIG. 3, which will be described below.
(Step 1) The target value of the work roll profile at the evaluation points A, B, C... Is set in the rolling order for each material to be rolled. It is preferable that the center of the body length of the work roll and the left and right evaluation points A, B, C... Are connected by a quadratic curve such as a parabola or an ellipse.

(Step 2) If it is desired to set an upper limit for the amount of change in the work roll shift position (work roll shift pitch) with respect to the previous rolled material and the next rolled material, XP _max is manually input. This step may be omitted when the platenability of the material to be rolled tends to be unstable, for example, a thin material with a finished thickness of 2.3 mm or less is not included in the rolling cycle. .
(Step 3) Under the conditions of Steps 1 and 2 above, all the rolled materials scheduled for rolling in the rolling cycle are rolled so as to approach the target value of the work roll profile when each rolled material is rolled. Determine the forward work roll shift position.

  In the above (Step 3), even when an upper limit is set for the work roll shift pitch, the number of combinations of rolling order work roll shift positions for all the rolled materials scheduled to be rolled in the rolling cycle is enormous. For the combination, the evaluation function J is calculated for each evaluation point, totaled, and the total of all the rolled materials is selected, and then the total roll order work roll shift position that minimizes the total result of the evaluation function J is selected. Of course, in order to reduce the calculation load, the following method can be used.

(Step 3-1) First, assuming the case where the first material to be rolled is rolled in the rolling cycle at the initial work roll shift position, the calculated work roll profile predicted value after rolling (work The initial radius of the roll, thermal expansion, and total wear) are predicted by calculation for evaluation points A, B, C,.
And the result which calculated the evaluation function J determined from a work roll profile target value and a work roll profile prediction calculation value about the evaluation point of the width end multiple places of a to-be-rolled material is totaled.

Here, the initial work roll shift position may be assumed to be a representative position within the equipment specification range, for example, the work roll shift position X = 0 mm.
(Step 3-2) Next, the work roll shift position when rolling the first material to be rolled is set to X ₁ = 0 mm, and the work roll shift pitch is set to a certain constant such as XP = 50 mm, for example. For example, when rolling the second material to be rolled, it is assumed that the work roll shift position is set to X ₂ = XP, or X ₂ = 0 mm without changing from the first material. The roll profile is predicted by calculation for each evaluation point, and the results of calculating the evaluation function J for each evaluation point are summed up.

When rolling the third and subsequent workpieces, the work roll shift position is X _k = X _k-1 + XP, X _k = X _k-1 -XP, or the previous workpiece Assuming that X _k = X _k−1 without changing to a rolled material, the work roll profile after rolling is predicted by calculation for each evaluation point, and the evaluation function J is calculated for each evaluation point.
When the work roll shift position reaches the end of the machine specifications, the work roll shift position for the next material to be rolled is turned back to X _k = X _k−1 −XP, or the previous roll Assuming that X _k = X _k-1 without changing to the material to be rolled, the work roll profile after rolling is predicted by calculation for each evaluation point, and the evaluation function J is calculated for each evaluation point. .

  In summary, for the material to be rolled next, the work roll shift position that differs from the work roll shift position for the previous rolled material by the amount of the work roll shift pitch and the same work roll as the previous rolled material. Assuming one or more of the shift positions, the work roll profile after rolling is predicted by calculation for each evaluation point, the result of calculating the evaluation function J for each evaluation point is summed, and the total result is minimized. A series of processes for determining the work roll shift position to be set for the next rolled material to be rolled is repeated for all the rolled materials to be rolled in the rolling cycle.

  It should be noted that the evaluation function has the same value at the work roll shift position that differs from the work roll shift position by the amount of the work roll shift pitch and the same work roll shift position as the previous work roll. In such a case, priority is given to changing the work roll shift position, and priority is given to the work roll shift direction having the same sign as the previous material to be rolled. This is to prevent accumulation of thermal expansion and wear.

When the upper limit XP _max is set for the work roll shift pitch in step 2, when rolling the second and subsequent workpieces, the work roll shift pitch is set to a certain constant such as XP = 50 mm, for example. , The smaller of XP _max .
(Step 3-3) Furthermore, the initial work roll shift position assumed in Step 3-1 is changed, and only the work roll shift position when rolling the first rolled material is set to X ₁ = XP. After rolling the material to be rolled, a cyclic shift that expands the work roll shift position such that X ₂ = XP + XP, X ₃ = XP + 2XP, X ₄ = XP + 3XP, X _k = XP + (k-1) XP in addition in the case of rolling in a way, only the work roll shift position when rolling the first run of the rolled material _{X 1 = 2XP, X 1 =} 3XP, assuming one after another when rolled as ..., each The work roll profile after rolling the material to be rolled is predicted by calculation for evaluation points A, B, C,.

This (Step 3-3) may be omitted if the initial work roll shift position for the first material to be rolled is always X = 0 mm.
In the above, the thermal expansion and wear of the work roll are predicted by the above-mentioned formulas (4) and (5), etc., and for all the rolled materials in the rolling cycle, the expected thickness after rolling in each rolling mill and In addition to the width, the rolling time, the rolling interval, etc. are predicted before the start of the rolling cycle, and the result of predicting the work roll temperature based on the calculation is reflected in the calculations of equations (4) and (5). The rolling load and the like are also predicted and calculated by logic not described in detail before the rolling cycle is started, and are reflected in the calculations of equations (4) and (5). The prediction of the rolling interval is performed by reflecting the prediction calculation result of the target heating temperature arrival time of each material to be rolled in the heating furnace 10, which is separately performed.

  (Step 3-4) The calculation in each of the above steps is performed, and the evaluation function J of Expression (7) is calculated for the evaluation points at the width end multiple places of the material to be rolled, and is totaled as in Expression (8). Further, a roll order work roll shift position is obtained such that the sum (9) of all the rolled materials scheduled to be rolled in the rolling cycle is minimized, and is output as an optimum solution.

By doing so, the rolling order work roll shift position is determined for all the rolled materials scheduled to be rolled in the rolling cycle so that the work roll profile approaches the target value.
(Step 3-5) or, further, the work roll shift pitch at the rolling order work roll shift position for all the rolled materials scheduled to be rolled in the rolling cycle, which is output as the optimal solution, is set to α times XP (0 There are two cases: <α <1 and 1 <α, where αXP ≦ XP _max ), and the above-mentioned evaluation function is calculated again for evaluation points at a plurality of width edges of the material to be rolled. If the result is smaller than the case where it is not multiplied by α, the work solution shift pitch may be replaced with the above-described optimal solution with the result of multiplying XP by α. In this case, the work roll shift pitch does not necessarily have to be changed at an equal pitch from one rolled material to the next rolled material, and a more appropriate rolling order work roll shift position can be obtained.

As an example here, assuming that the work roll shift position of X = ± 300 mm can be taken as the specification of the work roll shift equipment, and the work roll shift pitch XP is 50 mm, the first material to be rolled is rolled. The number of repetitions of calculation required to change the work roll shift position to X ₁ = 2XP, X ₁ = 3XP, ... starts from each point obtained by dividing 300mm by 50mm. Considering both the case where the position changes to the larger side and the case where the position changes to the smaller side, the direction on the -300 mm side does not have to be calculated considering the objectivity. The maximum is 12 times.

In practice, however, the work roll shift position when rolling the first run of the rolled material _{X 1 = 2XP, X 1 =} 3XP, calculates an evaluation function J whenever a will change and ..., the evaluation function in the middle Even if it is judged that the evaluation function J is minimized by repeating the previous calculation when J is minimized and changes to the first increasing side, there is no practical problem. In many cases, a small number of calculations are required.

  In addition, instead of the above calculation, for example, by using non-linear programming or the like, an optimal solution may be obtained by repeated calculation several times. As long as the roll order work roll shift position is determined so that the result obtained by adding and summing all of the rolled materials scheduled to be rolled in the rolling cycle is minimized, the above calculation is performed. It is not limited to how.

  (Example 1) In a hot rolling line 100 shown in FIG. 10 having a finish rolling mill 18 equipped with work roll shift rolling mills equipped with work roll benders as F1 to F7, the rolling order as shown in FIG. Applying the work roll shift position determination method of the present invention to the rolling cycle of thickness and width configuration, for each rolled material, the thickness profile in the rolled material width direction after rolling is simulated by calculation. saw. Table 2 shows the equipment specifications of the rolling mill.

  The evaluation points were three points of 25 mm (A), 75 mm (C), and 150 mm (E) from the widest end of the material to be rolled, and the upper limit of the work roll shift pitch was 20 mm. A series of processes for calculating the evaluation function for the rolling order work roll shift position assumed using the random number table is repeated, and the rolling order work roll shift position at which the evaluation function is minimized is selected from all the rolling order work roll shift positions. Selected and rolled. Evaluation of the thickness profile of the rolled material after rolling was performed on the 66th rolled material in which the width of the rolled material is about 300 mm wider than the width of the previous rolled material. For comparison with the prior art, the work roll shift position determination method by the conventional cyclic shift method was tried in the rolling cycle having the same rolling thickness and width as in FIG.

  FIG. 5 shows the work roll shift position according to the method of the present invention. The work roll shift positions of the odd-numbered rolling mills such as F1, F3, F5, and F7 are as shown in FIG. 5, and the signs of the work roll shift positions of the even-numbered rolling mills such as F2, F4, and F6 are reversed. To do. In such a case, in actual rolling that is not a simulation, even if uneven wear occurs in the work roll, the uneven wear is transferred to the work roll of the subsequent rolling mill and the material to be rolled is prevented from meandering. Because it can.

  Conventionally, every time one rolled material is rolled at a constant work roll shift pitch, the work roll shift position is expanded, and after rolling the 16th rolled material that has reached the end of 300 mm in the machine specifications, In contrast to the cyclic shift method in which the shift is continued and the shift is continued, when the method of the present invention is used, the material to be rolled in the first half of the rolling cycle is as wide as about 1600 mm. Since it occurs widely in the long direction, it is predicted that it is advantageous to flatten the thickness profile by increasing the thermal expansion by rolling the ninth material to be rolled. The 19th material to be rolled is turned back again after rolling, while the finished thickness up to the previous material to be rolled was as thin as about 3 mm, while the finished thickness after the material to be rolled is as thick as over 4 mm. Since some things continue, the rolling load is reduced, so the deflection of the work roll is reduced, and the work roll shift position is reduced and the thermal expansion is increased, which is advantageous for flattening the thickness profile. Therefore, the prediction calculation is performed so that the work roll shift position is turned back to the smaller side.

FIG. 6 shows the 66th thickness profile. When the conventional cyclic shift method is used, the reverse crown is about 20 μm. However, according to the method of the present invention, no reverse crown is generated. Has a good thickness profile. In addition, an abnormal thickness profile does not occur in the materials other than the 66th rolled material.
(Example 2) In a hot rolling line 100 having a finish rolling mill 18 equipped with cross roll shift rolling mills equipped with work roll benders as F1 to F6, the rolling order thickness and width configuration as shown in FIG. For the rolling cycle, the work roll shift position determination method of the present invention was applied, and for each material to be rolled, the thickness profile in the width direction after rolling was simulated by calculation. Table 3 shows the equipment specifications of the rolling mill.

  The evaluation points were 4 points from the widest end of the material to be rolled: 50 mm (B), 100 mm (D), 150 mm (E), and 200 mm (F), and the upper limit of the work roll shift pitch was 20 mm. A series of processes for calculating the evaluation function for the rolling order work roll shift position assumed using the random number table is repeated, and the rolling order work roll shift position at which the evaluation function is minimized is selected from all the rolling order work roll shift positions. Selected and rolled. The thickness profile of the rolled material after rolling was evaluated for the 62nd rolled material in which the width of the rolled material was about 150 mm wider than the width of the previous rolled material. For comparison with the prior art, the work roll shift position determination method by the conventional cyclic shift method was tried in the rolling cycle having the same rolling order thickness and width configuration as in FIG.

FIG. 8 shows the work roll shift position according to the method of the present invention. The work roll shift position of the odd-numbered rolling mill is as shown in FIG. 8, and the sign of the work roll shift position of the even-numbered rolling mill is the same as in the first embodiment.
Conventionally, every time one rolled material is rolled at a constant work roll shift pitch, the work roll shift position is expanded, and after rolling the tenth rolled material that has reached the end of 180 mm in the machine specifications, Whereas the cyclic shift method of continuing the shift by turning back was adopted, the width of the material to be rolled in the first half of the rolling cycle was relatively narrow, about 900 to 1200 mm, even when the method of the present invention was adopted. Is widely calculated in the body length direction of the work roll, so that the twelfth material to be rolled is rolled and then predicted to be folded.

  The 21st material to be rolled is turned back after being rolled, because the finish thickness up to the previous material to be rolled and the finish thickness after the material to be rolled are as thin as 2mm and the rolling length is long. In order to disperse wear widely in the length direction of the work roll due to rapid progress, it is better to increase the work roll shift position as quickly as possible before the work roll shift position reaches 0 mm. This is because it is advantageous to prevent the film from becoming overly thick. For the same reason, the 64th material to be rolled is rolled back after being rolled.

  The 28th and 62nd materials to be rolled are turned back after being rolled, and the width of the material to be rolled constituting the rolling cycle is often as narrow as about 800 to 900 mm, so that the thermal expansion occurs in the body length direction of the work roll. Since it is distributed only narrowly, it is predicted that it is predicted that it is advantageous to flatten the thickness profile by increasing the thermal expansion by rolling the 28th and 62nd rolled materials and then turning them back.

FIG. 9 shows the thickness profile of the 62nd line. When the conventional cyclic shift method was used, the reverse crown was about 10 μm. However, according to the method of the present invention, no reverse crown was generated. Has a good thickness profile. Moreover, the abnormal thickness profile has not arisen about the to-be-rolled material other than the 62nd.
As described above. In the above description, the case where the present invention is applied to the hot rolling line 100 is taken as an example. However, the present invention can be applied to other metal strip rolling lines such as a cold rolling line. No problem.

Further, the present invention can determine the rolling order work roll shift position for all the rolled materials scheduled to be rolled in the rolling cycle before rolling the first rolled material in the rolling cycle. There is no problem even if it is used to determine the work roll shift position when rolling the material to be rolled after the next material to be rolled after rolling up to the material to be rolled in the middle.
If the work roll shift position determination method of the present invention is used for the production of a metal strip, when rolling the material to be rolled, the problem of reverse crown, the thickness of the width end of the material to be rolled becomes excessively thin or excessively thick. Can solve the problem. Thereby, it is possible to stably and reliably realize schedule-free in the production of the metal strip.

DESCRIPTION OF SYMBOLS 1 Slab manufacture 7 Roller table 8 Rolled material 9 Width press 10 Heating furnace 12 Rough rolling mill 13 Edger roll 14 Crop shear 15 Finishing side thermometer 16 Descaling device 18 Finishing mill 19 Work roll 20 Backup roll 21 Finishing Side thermometer 22 Finishing side thickness gauge 23 Runout table 24 Coiler 25 Coiler inlet side thermometer 50 Controller 70 Process computer 90 Business computer 100 Hot rolling line A Conveying direction

Claims (3)

When rolling a material to be rolled using a work roll shift rolling mill in a metal strip rolling line,
Assuming the rolling order work roll shift position for all the rolled materials scheduled for rolling in the rolling cycle,
The evaluation function of the following formula (7) determined from the target value and the predicted calculation value of the work roll profile of the work roll shift rolling mill is calculated for the evaluation points at a plurality of width ends of the material to be rolled, and the following formula (8) And totaled as shown in the following formula (9) for all the rolled materials:
Assuming different rolling order work roll shift positions,
The evaluation function of the formula (7) is calculated for evaluation points at a plurality of width end portions of the material to be rolled, and is summed as in the formula (8). Repeat a series of processes to sum up,
A work roll shift rolling method in a metal strip rolling line, wherein a rolling order work roll shift position that minimizes the formula (9) is selected from all rolling order work roll shift positions.
Record

When rolling a material to be rolled using a work roll shift rolling mill in a metal strip rolling line,
Assuming the work roll shift position for the first material to be rolled in the rolling cycle, the work roll profile prediction calculation value after rolling is predicted by calculating the evaluation points at the multiple width edges of the material. And
The evaluation function of the following formula (7) determined from the work roll profile target value and the work roll profile prediction calculation value of the work roll shift rolling mill is calculated with respect to the following formula (7) 8) total
For the material to be rolled next to the material to be rolled, the work roll shift position for the previous material to be rolled differs from the work roll shift position by the amount of the work roll shift pitch, and the same work as the material to be rolled. Assuming one or more of the roll shift positions, the work roll profile after rolling is predicted by calculation for each evaluation point, and the evaluation function of the equation (7) is calculated for each evaluation point. A series of processes for determining the work roll shift position that is totaled as in the formula (8) and that minimizes the totaled result for the material to be rolled next, is scheduled to be rolled in the rolling cycle. By repeating for all rolled materials,
The evaluation function of the formula (7) is calculated for the evaluation points at the width end multiple places of the material to be rolled, and the sum is calculated as in the formula (8), and this is further summed for all the materials to be rolled (9 ) Is a work roll shift rolling method in a metal strip rolling line, wherein the roll order work roll shift position is minimized.
Record

  The work roll shift rolling method according to claim 1, wherein an upper limit is provided for the work roll shift pitch.

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