JP3610819B2 - Sheet speed prediction method in rolling. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to rolling of a plate material, and more particularly to a method for predicting a plate speed with high accuracy without installing a plate speed meter on the delivery side of the rolling mill, which can be suitably used for hot rolling.
[0002]
[Prior art]
In rolling plate materials, it is important to predict the plate speed on the exit side of the rolling mill with high accuracy. In the case of a tandem rolling mill, when the material to be rolled is wound up by a winder subsequent to rolling, or when a cutting facility for shear-cutting the material to be rolled is subsequently installed in the rolling mill, In order to synchronize between the rolling mill and the equipment installed subsequently, it is necessary to accurately know the plate speed on the outlet side of the rolling mill.
[0003]
If the plate speed on the exit side of the rolling mill is incorrectly predicted, in the case of a tandem rolling mill, slack of the material to be rolled or abnormal tension occurs between the stands, which may cause trouble in rolling. If slack of the plate occurs between the stands, it may be rolled in the state where the plates overlap in the next stand (sloppy state). If the tension between the stands becomes abnormally high, the plate width may be greatly reduced or extreme In some cases, the plate may break. Similarly, when a winder is installed on the exit side of the rolling mill, if the plate speed on the exit side of the rolling mill is incorrectly estimated, the speed between the rolling mill and the winder cannot be synchronized, and the slack of the material to be rolled Or tension occurs. In addition, when a cutting machine is installed on the exit side of the rolling mill, if the estimation of the plate speed on the exit side of the rolling mill is mistaken, the cutting length and cutting position of the material to be rolled do not become desired. Thus, accurately obtaining the sheet speed on the delivery side of the rolling mill is important for improving the stability of the rolling operation and improving the dimensional quality of the product.
[0004]
Many studies have been made in order to obtain the sheet speed on the exit side of the rolling mill. For example, JP-A-8-71623 discloses rolling using a sheet speed meter that measures the sheet speed without contacting the material to be rolled. A method for measuring the speed at the exit side is shown. In this method, it is necessary to install a device for measuring the plate speed of the material to be rolled, and there is a disadvantage that the equipment cost is increased. Of course, the speed of the material to be rolled can be measured only during rolling, and the plate speed on the exit side of the rolling mill is predicted before rolling, and the operation speed of the equipment adjacent to the rolling mill and the rolling mill is set. Has the disadvantage that the measured plate speed cannot be used.
[0005]
Japanese Patent Application Laid-Open No. 6-246318 discloses a method for predicting the advance rate (the rate of increase in the sheet speed on the rolling mill exit side with respect to the roll peripheral speed). The technique described in Japanese Patent Laid-Open No. 6-246318 is directly measured when predicting the advanced rate based on the rolling theory related to hot rolling such as the Sims equation, the Orowan differential equation, the Tamano / Yanamoto equation, etc. It is intended to improve the accuracy of predicting the advanced rate by estimating the impossible items (for example, friction coefficient) by other means.
[0006]
However, with the conventional method that predicts the advanced rate depending only on the rolling theory, sufficient prediction accuracy may not be obtained depending on the rolling conditions. For example, the advanced rate is required for rolling under high pressure on hard and thin materials. There has been a problem that the prediction accuracy of.
Therefore, the present inventors first calculated the flat roll radius and the advanced rate according to the rolling theoretical formula in which the flat shape of the roll at the time of rolling is an arc in Japanese Patent Application No. 10-159167, and the advanced rate is calculated as the roll flat ratio (above-mentioned). A plate speed prediction method in rolling is proposed, which is corrected based on (flat roll radius / roll radius).
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to improve the plate speed prediction method, or different from the plate speed prediction method, and does not require the installation of a plate speed meter, and is also used in the high-pressure rolling of hard materials and thin materials. Provided is a plate speed prediction method in rolling which can predict a delivery side plate speed with good accuracy.
[0008]
[Means for Solving the Problems]
The first invention is a method of predicting the sheet speed on the delivery side of the rolling mill from the advanced rate when rolling the plate material with a rolling mill, and at least using the entry side and exit side sheet thicknesses and the roll radius, the roll flat shape during rolling The flat roll radius and the advanced rate are calculated based on the rolling theory with the arc as the arc, and the advanced rate is calculated based on the roll flat ratio (the flat roll radius / the roll radius). It is a sheet speed prediction method in rolling, characterized in that correction is made so as to differ between a range and a range of not less than the predetermined value and not more than 20.
[0009]
In the present invention, the roll flatness ratio is set to a range of 20 or less because if this value is exceeded, rolling becomes impossible.
Further, when the ratio between the corrected advanced rate corrected by the plate speed prediction method and the reduction rate obtained from the inlet side and outlet side plate thickness exceeds a predetermined ratio, the corrected advanced rate is reduced to the reduction rate. It is a plate speed prediction method in rolling, characterized in that the product of the rate and the predetermined ratio.
[0010]
The second invention is a method of predicting the sheet speed on the delivery side of the rolling mill from the advanced rate when rolling the sheet material with a rolling mill, and at least using the entry side and exit side sheet thicknesses and the roll radius, the roll flat shape during rolling The flat roll radius is calculated based on the rolling theory with a circular arc, and the advance rate is obtained by correcting the rolling reduction obtained from the inlet and outlet plate thicknesses based on the roll flat ratio (the flat roll radius / roll radius). This is a method for predicting the plate speed in rolling.
[0011]
Moreover, it is preferable to apply the plate speed prediction method in the rolling of the first invention or the second invention to the setting calculation before rolling. In that case, the entry side and exit side plate thicknesses and roll radii described in the first invention or the second invention are set as set values, and in addition, set values for entry and exit side tensions, set values for deformation resistance and friction coefficient. The Young's modulus of the roll may be used.
[0012]
Moreover, it is preferable to apply the plate speed prediction method in rolling according to the first invention or the second invention to dynamic control during rolling. In that case, the entry side and exit side plate thicknesses described in the first invention or the second invention are used as predicted values or measured values, the roll radius is used as a measured value, and additionally, the measured values of the rotational speed and rolling load of the roll. The measured value of the Young's modulus of the roll may be used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In order to achieve the above object, the present inventors investigated the actual state of the plate speed on the exit side of the finish rolling mill in the actual hot rolling facility exemplified in FIG. This hot rolling equipment includes three rough mills 1 and a seven tandem finish rolling mill 2 as a hot rolling mill, and a coiler 3 downstream of the finishing rolling mill 2. Further, a strip shear 7 for cutting the plate is provided upstream of the coiler 3.
[0014]
A pinch roll 4 for stably guiding the material to be rolled to the coiler 3 is installed on the entry side of the coiler 3. The pinch roll 4 is controlled so as to perform no-load rotation when passing through the steady rolling section, and is considered to be rotating at the same peripheral speed as the plate speed. Accordingly, by actually measuring the rotational speed of the pinch roll and the roll rotational speed of the finishing mill final stand (finishing final stand), the measured advanced rate in the stand can be obtained.
[0015]
In addition, an X-ray thickness gauge 5 is installed on the entry side and the exit side of the finishing final stand, and the rolling reduction at the stand can be accurately measured. A load cell (load meter) 6 for measuring the rolling load is incorporated in all finishing stands.
Here, the relationship between the roll peripheral speed and the plate speed on the entry / exit side of the rolling mill will be described.
The material to be rolled passes through the upper and lower roll gaps and is reduced in thickness. At that time, the speed of the material to be rolled increases according to the thickness reduction amount under the condition of a constant volume. Usually, in the contact area (roll bite) between the roll and the material to be rolled, there is a point where the speed of the material to be rolled and the peripheral speed of the roll coincide with each other, which is called a neutral point. The speed of the material to be rolled is slower than the roll peripheral speed at the roll bite entry side at the neutral point, and the speed of the material to be rolled is higher than the roll peripheral speed at the roll bite exit side. The neutral point position can be calculated by a rolling theoretical formula based on the balance of forces in the roll bite. If the position of the neutral point is known, the plate thickness at the neutral point can be found from the geometric shape of the roll, and the speed of the material to be rolled on the delivery side and the entry side of the rolling mill can be seen from the condition of constant volume velocity. As the theoretical rolling formula, the Sims formula, Orowan differential equation, Tamano / Yanamoto formula, etc. are known for hot rolling. For example, Chapter 2 of "Theory and Practice of Sheet Rolling: Japan Iron and Steel Institute" It is explained in detail in textbooks on rolling theory.
[0016]
First, in order to verify the accuracy of the calculated advanced rate calculated from the conventional rolling theory, the calculated advanced rate was compared with the measured advanced rate. As the conventional calculation advance rate, the formula of Tamano and Yanagimoto (for example, edited by Japan Iron and Steel Institute, “Theory and Practice of Plate Rolling”, P37-38) among the above-described theoretical formulas for rolling was used.
Assuming that the coefficient of friction that cannot be directly measured in the equation is 0.2, the deformation resistance is calculated backward using the rolling theory equation (rolling load equation), and the deformation resistance calculated backward from the assumed friction coefficient is used. Advanced rate was calculated.
[0017]
FIG. 3 is a correlation diagram between the calculated advanced rate and the measured advanced rate indicating the prediction accuracy of the advanced rate according to the conventional method. In many cases, the calculated value and the actually measured value coincide well, but the actually measured value may be much larger than the calculated value. In order to see when such a situation with a large degree of discrepancy occurs, we investigated the relationship between the difference between the measured advanced rate and the calculated advanced rate (advance rate error = prediction error) and various rolling factors. Shown in As rolling factors, (a) outlet side plate thickness, (b) deformation resistance, (c) roll material (roll Young's modulus), and (d) roll diameter were adopted. The advance rate error tends to increase as the exit side plate thickness decreases, the deformation resistance increases, the roll Young's modulus decreases, and the roll diameter increases. Thus, in the conventional rolling theory, the actual advanced rate may not be accurately predicted. Further, even if the calculation advance rate is simply corrected by various rolling factors, such a simple correction is difficult because an error variation under the same condition is large in a region where the prediction error is large.
[0018]
Therefore, the present inventors went back to the basics and examined the cause of the difference between the calculated advanced rate calculated from the conventional rolling theory and the actual advanced rate. In the first place, the conventional rolling theory is the basic form of the differential equation representing the balance of forces in the roll bite under some assumptions. The main assumptions in the above Tamano and Yanagimoto rolling theory are:
(A) The material to be rolled is a rigid plastic body (elastic deformation of the material to be rolled is ignored).
[0019]
(B) The roll is an elastic body and deforms flatly by a load from the material. However, the roll shape after flattening (circumferential surface shape = cross-sectional shape in the roll radial direction) is assumed to be an arc shape (the flat roll radius formula of hitchcock is used).
(C) The friction coefficient is constant in the roll tool. However, the shear stress between the roll and the material to be rolled should not exceed the shear yield stress of the material.
[0020]
Etc.
Even if the other conditions are the same, when the Young's modulus of the roll is small, the difference between the measured advanced rate and the calculated advanced rate tends to increase. Therefore, in actual rolling, there is a rolling condition in which the above assumption (B) is not satisfied. I hypothesized that there is.
That is, as shown in the conceptual diagram of FIG. 5, the rolling pressure increases from the entry side toward the neutral point in the roll bite, and the rolling pressure decreases from the neutral point toward the exit side. It becomes the rolling pressure distribution of the shape. When the friction hill is small, the flat deformation of the roll is relatively uniform, and the roll shape after flattening (roll flat shape) is also maintained in an arc shape (FIG. 5A). However, when the friction hill is large, the roll flatness near the neutral point, which is the peak position of the friction hill, becomes very large, and the roll flat shape is no longer an arc shape (FIG. 5B). There is a possibility, and in such a situation, the plate thickness at the neutral point becomes thicker than in the case of the arc-shaped roll flat (FIG. 5A), and it is considered that the advance rate increases.
[0021]
According to the results of the rolling experiment, (1) when the plate thickness is thin, (2) when the deformation resistance is large, (3) the larger the roll diameter, (4) the smaller the Young's modulus of the roll, The prediction error is large. (1) to (3) are all conditions that increase the friction hill, and (4) is a condition that increases the flat deformation of the roll. If the rate is considered to be large, the experimental results can be explained without contradiction. That is, in the hot rolling of thin and hard materials, it is presumed that there is a condition that (B) does not hold in the assumption of the conventional rolling theory.
[0022]
The validity of this hypothesis was verified by numerical calculation. FIG. 6 shows the rolling direction obtained by iterative calculation in which the roll flat shape by the friction hill in the roll bite is faithfully calculated according to the theory of elasticity, and the balance formula of the force in the roll bite is solved using the roll flat shape. It can be seen that the amount of flat deformation near the neutral point is large as in the above hypothesis. In addition, the calculated value of advanced rate (not shown) corresponding to this is much larger than the value of the conventional rolling theory model formula (in this case, Tamano and Yanagimoto formula), and is close to the measured advanced rate. It was.
[0023]
In this way, the knowledge that the prediction accuracy of the advanced rate can be improved by using the exact solution of the roll flat shape considering non-arc deformation is obtained, but the advanced rate of such exact solution (considering non-arc deformation) As described above, since the calculation advance rate requires a considerable calculation time to be obtained by the iterative calculation method, the solution cannot be applied as it is to online setting calculation or dynamic control.
[0024]
Therefore, we considered improving the prediction accuracy of the advanced rate using parameters that can be easily calculated from the rolling conditions. As described above, since the advance rate increases when the friction hill is large and the roll flattened, the roll flatness ratio (roll radius after flattening / roll radius before flattening) representing the degree of flattening of the roll is calculated. As a parameter, the ratio of the calculated advanced rate considering the non-arc deformation and the calculated advanced rate based on the conventional model (using the hitchcock flat roll radius formula that keeps the roll flat shape arc) (referred to as the advanced rate ratio) They are organized and shown in FIG.
[0025]
From this result, the advanced rate ratio can be arranged so that the variation becomes smaller with the roll flatness ratio, and the relationship between the advanced rate ratio and the roll flatness ratio becomes a boundary between the roll flatness ratios at a predetermined value in the range of 3 to 4 of the roll flatness ratio. It was found that the range with a small ratio was different from that with a large range.
Therefore, if the calculation advance rate according to the conventional model is corrected to be different between a range of 1 or more and less than a predetermined value and a range of more than or equal to a predetermined value and 20 or less based on the roll aspect ratio, the rolling mill delivery side plate speed may vary. Small and accurate predictions can be made. In particular, the calculation advanced rate according to the conventional model is multiplied by the advanced rate ratio expressed by a linear expression of the roll flat ratio, which is different between the range of 1 or more and less than the predetermined value and the range of the predetermined value or more and 20 or less. It is preferable to use the advanced rate used for plate speed prediction.
[0026]
The first invention has been completed based on such knowledge.
According to the first invention, since the relationship as shown in FIG. 7A is used, it is possible to accurately calculate the plate speed in the online setting calculation and dynamic control.
FIG. 7B shows the relationship between the ratio of the calculated advanced rate and rolling reduction considering non-arc deformation (calculated advanced rate / rolling rate considering non-arc deformation) and the above roll flatness ratio. Came to show. Here, the rolling reduction is obtained from the inlet side and outlet side plate thicknesses.
[0027]
From these results, the calculated advanced rate / rolling rate considering non-arc deformation can be arranged so that the variation is reduced by the roll flatness ratio, and the relationship between the calculated advanced rate / rolling rate and roll flatness ratio considering non-arc deformation However, it turns out that it is different in the range with a small roll flat ratio, and the large range on the boundary of the predetermined value of the range of 3-4 of roll flat ratio.
Therefore, when the rolling reduction ratio obtained from the inlet and outlet sheet thicknesses is corrected based on the roll flatness ratio (the flat roll radius / roll radius) to obtain the advanced ratio, the rolling mill outlet side plate speed is accurate with small variations. Can be predicted. Further, it is preferable that the roll flatness ratio is corrected to be different between a range of 1 or more and less than a predetermined value and a range of a predetermined value or more and 20 or less. In particular, the roll reduction ratio obtained from the inlet and outlet plate thicknesses is expressed by a linear expression of the roll flat ratio, which is different in a roll flat ratio of 1 or more and less than a predetermined value and greater than or equal to a predetermined value and 20 or less. It is preferable that a product obtained by multiplying a ratio of a calculated advance rate and a reduction rate in consideration of arc deformation to be an advance rate used for plate speed prediction.
[0028]
The second invention has been completed based on such knowledge.
According to the second aspect of the invention, since the relationship as shown in FIG. 7B is used, it is possible to accurately calculate the plate speed in online setting calculation and dynamic control.
By the way, the relationship between the calculated advance rate / rolling rate considering the non-arc deformation shown in FIG. 7B and the roll flat ratio is calculated when the roll flat ratio exceeds 4, the calculated advanced rate / rolling considering the non-arc deformation. The rate is constant at about 0.7 to 0.8. The reason for this is that when the neutral point is located on the roll bite exit side, the reduction rate after the neutral point is zero, so the advance rate becomes zero, and when the neutral point is located on the roll bite entry side, the reduction rate after the neutral point is Since the reduction ratio is equal to the reduction ratio obtained from the entry side and exit side plate thicknesses, the advance rate coincides with the reduction ratio obtained from the entry side and exit side plate thicknesses. That is, the advanced rate / reduction rate should be 0 or more and 1 or less. Actually, because of the flat shape of the roll when the neutral point is located at the entry point of the roll bite, the upper limit is about 0.7 to 0.8 regardless of the rolling conditions. It is estimated that it will not exceed.
[0029]
Therefore, when the ratio between the advanced rate after correction of the first invention and the reduction rate obtained from the inlet and outlet side plate thickness exceeds a predetermined ratio, the corrected advanced rate is determined as the reduction rate and the predetermined ratio. By using this product, it is possible to prevent the calculation advance rate after correction from becoming too large and causing trouble in rolling.
A flow chart of the plate speed prediction procedure according to the first invention is shown in FIG. 1A corresponds to the setting calculation before rolling, and FIG. 1B corresponds to the dynamic control during rolling.
[0030]
In the setting calculation before rolling according to the first invention, as shown in FIG. 1A, set values such as input / output side plate thickness, input / output side tension, deformation resistance, friction coefficient, roll diameter, roll Young's modulus, etc. Based on the above, the rolling load, the flat roll radius and the advanced rate are calculated by the rolling theoretical formula and the roll flat formula in which the roll flat shape at the time of rolling is an arc. The advanced rate calculated here is based on the conventional theory, and as described above, an error from the actually measured value increases depending on the rolling conditions. Since the flat roll radius is calculated, the roll flat ratio (the roll radius after flattening / the roll radius before flattening) can be calculated. Based on the roll flatness ratio, the advance rate is corrected so as to be different between a range where the roll flatness ratio is small and a large range based on the relationship shown in FIG. 7A, and the roll peripheral speed is corrected using the corrected advance rate. The plate speed is calculated from
[0031]
On the other hand, in the dynamic control at the time of rolling according to the first invention, as shown in FIG. 1 (b), the rolling theory that the roll flat shape at the time of rolling is an arc based on the measured values of the entry / exit side plate thickness and rolling load is shown. The flat roll radius and advanced rate are calculated by the formula. Here, with regard to the inlet / outlet side thickness, when there is a thickness gauge on the inlet / outlet side of the rolling mill, it is preferable to use the measured thickness by the thickness gauge, and when there is no thickness gauge, the reduction position It is preferable to use a calculated plate thickness such as a gauge meter plate thickness calculated from the rolling load and the mill rigidity. When the flat roll radius is obtained, the roll flat ratio (flat roll radius / roll radius) can be calculated, and the advance ratio is smaller than the relation of FIG. 7A based on this roll flat ratio. Correction is made so as to differ between the range and the large range, and the plate speed is calculated from the roll peripheral speed using the corrected advance rate. In the correction, it is preferable to correct with a linear expression of a roll flat ratio that is different between a range where the roll flat ratio is small and a large range. In addition, when the ratio between the corrected advanced rate and the reduction rate obtained from the inlet and outlet plate thickness exceeds a predetermined ratio, the corrected advanced rate is the product of the reduced rate and the predetermined ratio. Is preferred.
[0032]
FIG. 8 is a calculation-measurement correlation diagram showing the prediction accuracy of the advanced rate according to the first invention. The calculated advanced rate of the present invention is calculated as follows: when the ratio between the corrected advanced rate and the reduction rate obtained from the inlet and outlet side plate thickness exceeds a predetermined ratio, the corrected advanced rate is set to 0.8%. (The predetermined ratio was 0.8). As apparent from the comparison with FIG. 3 according to the conventional method, according to the first invention, the prediction accuracy of the advanced rate is remarkably improved.
[0033]
By the way, in the advanced rate predicted in FIG. 8, when the flat form of the roll is large, the advanced rate / rolling rate after correction was 0.9, but the advanced rate after correction was set to 0. Since the product of 8 was used, rolling was possible without causing any trouble in rolling.
In the setting calculation before rolling according to the second aspect of the invention, the roll flat shape at the time of rolling is based on the set values such as input / output side thickness, input / exit side tension, deformation resistance, friction coefficient, roll diameter, roll Young's modulus, etc. The rolling load and the flat roll radius are calculated by the rolling theoretical formula and the roll flat formula. The roll flat ratio (roll radius after flattening / roll radius before flattening) is calculated from the flat roll radius, and the rolling reduction is calculated from the input / output side plate thickness. The reduction rate is corrected from the relationship of FIG. 7B based on the roll flatness ratio to obtain the advance rate, and the plate speed is calculated from the roll peripheral speed using this advance rate.
[0034]
On the other hand, in the dynamic control at the time of rolling according to the second aspect of the invention, the flat roll radius is calculated by a rolling theoretical formula in which the flat shape of the roll at the time of rolling is an arc, based on the measured values of the inlet / outlet side plate thickness and rolling load. Here, for the inlet / outlet plate thickness, when there is a plate thickness meter on the inlet / outlet side of the rolling mill, it is preferable to use the measured plate thickness by the plate thickness meter. It is preferable to use a calculated plate thickness such as a gauge meter plate thickness calculated from the rolling load and the mill rigidity. The roll flatness ratio (flat roll radius / roll radius) can be calculated from the flat roll radius. Then, the reduction rate obtained from the inlet / outlet plate thickness is corrected from the relationship of FIG. 7B based on the roll flatness ratio to obtain the advanced rate, and the plate speed is calculated from the roll peripheral speed using this advanced rate. To do. When calculating the advance rate from the relationship of FIG. 7B, it is preferable to correct by a linear expression of the roll flat ratio, which is different between a predetermined range with a small roll flat ratio and a large range.
[0035]
【Example】
The exit side plate speed prediction method of the first invention is applied to the setting of rolling conditions in the hot rolling equipment (plate speed meter is not arranged) shown in FIG. 2, and the exit side plate speed prediction method of the second invention is applied to dynamic control. The effect when applying is described.
The exit plate speed prediction method of the first invention was applied, and the rolling speed, exit table roll speed, and coiler speed of each stand were set based on the predicted exit plate speed.
[0036]
As shown in Fig. 3, the conventional calculation advanced rate obtained from Tamano and Yanagimoto's formula may underestimate the advanced rate from the actual measurement. There was a case where an accident occurred. In addition, on the finishing delivery side, the plate may bump on the table roll, or the coiler may have a winding failure.
[0037]
FIG. 9 shows a comparison of the occurrence rate of the sheet passing trouble in the finish rolling mill and the occurrence rate of the winding failure trouble in the coiler before and after the application of the setting calculation according to the first invention. As shown in the figure, such troubles drastically decreased after the application of the first invention.
The effect of applying the second invention to dynamic control was evaluated by tracking accuracy. Tracking indicating how far the tracking point provided at an arbitrary position of the material to be rolled has been transferred with time from the finishing final stand is calculated based on the plate speed obtained from the roll peripheral speed and the advanced rate of the final stand. On the other hand, the actual tracking was measured by actually measuring the cutting position of the coil cut by the strip shear. A tracking error, which is the difference between the actually measured value and the calculated value, is compared before and after applying the second invention, and is shown in FIG. As shown in the figure, after the application of the second invention, the tracking error is greatly reduced in both the average value and the standard deviation (that is, the tracking accuracy is greatly improved), and the product yield is improved.
[0038]
In addition, although the present Example showed the application example to hot rolling, this invention is applicable also to cold rolling.
[0039]
【The invention's effect】
Thus, according to the present invention, since the accuracy of predicting the plate speed is improved, it is possible to prevent the trouble of passing through the tip portion, the trouble of winding in the coiler, the trouble of bleeding on the delivery side table, and the like. Moreover, since the roll peripheral speed of each stand of the finish rolling mill can be appropriately set as the plate speed prediction accuracy is improved, there is an effect of reducing the width defect and the thickness defect due to over tension.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a plate speed prediction procedure according to the present invention.
FIG. 2 is a layout diagram showing an example of hot rolling equipment suitable for carrying out the present invention.
FIG. 3 is a calculation-measurement correlation diagram showing the prediction accuracy of the advanced rate according to the conventional method.
FIG. 4 is a graph showing the relationship between a conventional advanced rate calculation error and various rolling factors.
FIG. 5 is a schematic diagram showing the influence of friction hills on the flat deformation of a roll.
FIG. 6 is a graph showing a roll gap shape in a rolling direction calculated in consideration of roll flat deformation caused by friction hills.
FIG. 7A is a graph showing a relationship between an advanced rate ratio and a roll flat ratio. (B) is a graph showing the relationship between the calculated advance rate / rolling rate and roll flatness ratio in consideration of non-arc deformation.
FIG. 8 is a calculation-measurement correlation diagram showing the prediction accuracy of the advanced rate according to the present invention.
FIG. 9 is a graph showing a trouble occurrence rate before and after applying the present invention.
FIG. 10 is a graph showing tracking errors before and after applying the present invention.
[Explanation of symbols]
1 Coarse mill 2 Finish rolling mill 3 Coiler 4 Pinch roll 5 X-ray thickness gauge 6 Load cell
7 Strip shear

Claims (3)

In the method of predicting the plate speed on the delivery side of the rolling mill from the advanced rate when rolling the plate material with a rolling mill, at least using the entry and exit side plate thicknesses and the roll radius, the roll flat shape at the time of rolling is an arc. The flat roll radius and the advanced rate are calculated by theory, and the advanced rate is calculated based on the roll flat ratio (the flat roll radius / the roll radius). The roll flat ratio is 1 or more and less than the predetermined value and the predetermined value. As described above, a sheet speed prediction method in rolling, wherein the correction is made so as to be different within a range of 20 or less. When the ratio between the advanced rate after correction corrected by the plate speed prediction method according to claim 1 and the rolling reduction obtained from the inlet and outlet plate thicknesses exceeds a predetermined ratio, the advanced rate after correction is corrected. Is a product of the rolling reduction and the predetermined ratio, a sheet speed prediction method in rolling. In the method of predicting the plate speed on the delivery side of the rolling mill from the advanced rate when rolling the plate material with a rolling mill, at least using the entry and exit side plate thickness and roll radius, the roll flat shape at the time of rolling is an arc. A flat roll radius is calculated by theory, and an advance rate is obtained by correcting a reduction rate obtained from the inlet and outlet side plate thicknesses based on a roll flat ratio (the flat roll radius / roll radius). Sheet speed prediction method in rolling.

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