JP5195528B2 - Method for predicting camber amount at room temperature and operation method using the same - Google Patents

Description

In the present invention, when a metal strip (metal strip or metal plate) after hot rolling is cooled on a run-out table, the amount of camber of the strip due to residual strain caused by uneven cooling, or the cut camber after the cut It relates to a method for predicting quantities.
Further, the present invention relates to a technique for manufacturing a metal strip using a camber amount prediction method in which a subsequent treatment is determined in accordance with a predicted camber amount and a load such as a refining process is reduced.

  Here, the definition of camber is shown. Camber is the amount of bending in the plate width direction defined for a predetermined length in the rolling direction. FIG. 9 shows an example of the shape of a plate bent in the width direction. The camber amount defined in FIG. 9 is a camber amount defined with respect to the length between positions A and B in the rolling direction.

  FIG. 10 shows a method of sequentially defining the geometric camber amount with the steel plate lateral runout amount during cold and, for example, a predetermined rolling direction length of 10 m. The geometric camber to be measured is defined as the amount of lateral touch that occurs with respect to the center of the string with the string stretched in the rolling direction. The geometric camber is sequentially measured by shifting the chord while maintaining a predetermined length in the rolling direction.

  FIG. 11 shows a plot of the geometric camber obtained by the method shown in FIG. 10 with respect to the rolling direction. The geometric camber amount can be sequentially measured after a predetermined length as a reference. The example shown here shows an example in which the geometric camber amount varies.

  At present, for example, in the hot rolling process of steel sheets, when the amount of steel plate camber after cooling becomes large, all of the steel sheets that are likely to meander in the continuous heat treatment equipment and continuous cold rolled steel sheet manufacturing equipment in the next process, and the steel sheets to be cut by the user Because the correction process is passed, the cost is increased. Originally, it is only necessary to predict the camber amount with high accuracy and correct as much as necessary without correcting the total amount.

  For such a situation, Patent Document 1 targets a thick steel plate, discretely measures the temperature in the width direction and the longitudinal direction of the steel plate with a thermoviewer, and also provides a balance equation of the measured temperature and strain. In addition, a method of estimating the camber amount of the entire steel sheet with a non-uniform temperature distribution by calculating the curvature at an arbitrary point in the steel sheet surface and integrating the curvatures is proposed.

Japanese Patent Publication No. 4-8128

  However, even if the evaluation formula for flatness disclosed in Patent Document 1 is applied to the evaluation of the camber amount of a hot-rolled steel sheet, the camber (rolling camber) generated by rolling and the influence of meandering are inherent. The camber amount of a steel plate having a uniform temperature has a problem that it is not accurate in prediction only by thermal strain generated when the temperature of the steel plate becomes uniform at normal temperature, and is not practically used.

  In other words, since the measured camber amount (geometric camber amount) of the steel sheet is due to the camber generated during rolling (rolling camber) or the apparent camber due to meandering, it is impossible to determine whether it is geometrical or not. The amount of scientific camber could not be applied for accurate prediction.

  In view of the above problems, the present invention has an object to provide a method for accurately predicting the camber amount of a hot-rolled steel sheet and to provide an operation method using the predicted camber amount.

  As a result of intensive studies, the inventors have conducted a superposition (addition) of the camber amount of the metal strip that has become a uniform temperature at room temperature by the camber amount due to thermal strain and the shape of the metal strip during rolling. And found out that the present invention is required.

  Furthermore, the camber amount resulting from the rolling shape of the metal strip is the camber amount obtained simultaneously with the temperature measurement in the plate width direction and the longitudinal direction (fixed temperature measurement method) by the thermometer 6 after the ROT, or the lateral runout of the steel plate. It was found that the amount of camber was determined from the amount of lateral displacement caused by a displacement meter (camber meter) for measuring the displacement.

The gist of the present invention is as follows.
(1) Hot finish rolled to a predetermined production size, cooled to a predetermined plate temperature by a cooling device to be made into a predetermined material, bent and bent back by a pinch roll, and wound into a coil shape In the method of predicting the camber amount at normal temperature of the metal strip to be used ,
Measure the surface temperature distribution of the steel sheet after runout table cooling with respect to the sheet width direction and the rolling direction,
Perform the balance calculation using the thermal strain at the time when the temperature distribution is then cooled and becomes uniform at room temperature, and determine the camber amount due to thermal strain,
Obtain the geometric camber amount measured from the amount of geometric camber obtained at the same time as the temperature measurement in the sheet width direction and rolling direction by the fixed point measurement method or the lateral runout amount provided by a separately installed displacement meter,
A method of predicting a camber amount at normal temperature of a metal strip, wherein the camber amount due to thermal strain and the geometric camber amount are overlapped.

  (2) The method for predicting the camber amount at the normal temperature of the metal strip according to (1), wherein the camber amount due to the thermal strain is obtained by a finite element method (hereinafter also referred to as FEM) using the temperature distribution. .

(3) Hot finish rolled to a predetermined production size, cooled to a predetermined plate temperature by a cooling device in order to make it into a predetermined material, bent and bent back by a pinch roll, and manufactured by winding in a coil shape In the method of predicting the camber amount at normal temperature of the metal strip to be used ,
Measure the surface temperature distribution of the steel sheet after runout table cooling with respect to the sheet width direction and the rolling direction,
Obtain the camber amount considering the out-of-plane deformation of the steel sheet by the FEM large deflection analysis considering the wave buckling using the thermal strain when the temperature distribution is then cooled and becomes uniform at room temperature,
Obtain the geometric camber amount obtained simultaneously with the temperature measurement in the sheet width direction and rolling direction by the fixed point temperature measurement method,
A method of predicting a camber amount at normal temperature of a metal strip, wherein the camber amount due to thermal strain and the geometric camber amount are overlapped.

  (4) A metal strip characterized by using the method for predicting a camber amount at normal temperature of a metal strip according to any one of (1) to (3), and passing through a refining process when a predetermined criterion is exceeded. Manufacturing method.

  (5) Using the camber amount prediction method at normal temperature of the strip according to any one of (1) to (3), an area exceeding a predetermined criterion is stored, and when unraveling the strip in the next process, A method for producing a metal strip, wherein a region beyond the criteria is shear-cut and a subsequent plate is passed.

  In the invention described in (1), the camber amount due to thermal strain obtained by balancing the residual strain generated during cooling of the camber generated when the coil after cooling is unwound by a predetermined thermal strain balance formula, and a fixed point It is possible to predict a camber amount with high accuracy by superimposing a geometric camber amount obtained from a lateral displacement amount provided by a temperature measuring method or a separately installed displacement meter.

  In the invention described in (2) above, a more accurate camber amount is obtained by using the FEM as a FEM instead of a simple method for the thermal strain balance and solving it strictly without ignoring the effect of continuity in the width direction. Can be predicted.

  In the invention described in the above (3), the camber prediction considering the out-of-plane deformation becomes possible by making the FEM analysis not only the bending analysis but also the large deflection analysis considering the elastic wave buckling, and the camber amount with higher accuracy. Can be predicted.

  In the invention described in the above (4), since the necessity determination of the refining process is performed using accurate camber prediction at normal temperature, the refining process is used efficiently.

  In the invention described in (5) above, by storing the area exceeding the predetermined criteria, and unrolling the strip in the next process, the area exceeding the criteria is shear-cut and the next plate is passed through It is not necessary to use the refining process itself.

It is the figure which showed the manufacturing equipment outline figure after the finish rolling mill in the manufacturing process of a hot-rolled steel plate. It is the figure which showed the correlation of the amount of lateral shake, and a telescopic amount. It is the figure which showed the correlation of the camber amount prediction only by thermal strain, and the measurement camber amount. It is the figure which showed the correlation of the prediction by this invention, and the measurement camber amount. It is the figure which showed the correlation of the camber prediction by geometric camber measurement, and the measurement camber amount. It is the figure which showed the camber amount estimated by this invention over the full length of a steel plate, and the camber amount measured. It is the figure which showed the correlation of the camber amount by this invention which considered buckling, and the measurement camber amount. It is sectional drawing of the hot rolled coil explaining the amount of telescopic. It is the figure which showed the board | curd bent in the width direction, and the definition of the camber amount. It is the figure which showed the method of defining a geometric camber amount from a lateral shake amount and this data. It is the figure which plotted the geometric camber calculated | required by the method shown by FIG. 10 with respect to the rolling direction. It is a figure explaining calculating | requiring the camber amount estimated based on the amount of geometric side shakes and the side shake by thermal strain. FIG. 12A simultaneously shows the actually measured lateral vibration amount (geometric lateral vibration amount) and the lateral vibration amount due to thermal strain (thermal strain lateral vibration amount). FIG. 12B shows a lateral shake amount obtained by adding up the actually measured lateral shake amount and the lateral shake amount due to thermal strain. FIG.12 (c) shows the camber amount calculated | required from FIG.12 (b).

The best mode for carrying out the present invention will be described below by taking a steel strip as an example.
The present invention can be applied not only to steel plates but also to all metal plates such as aluminum and copper, but it is assumed that application to steel (especially steel plates after a hot rolling process) is most demanded. Therefore, the present invention will be described below with reference to the drawings, taking a steel plate as an example.

  The present inventors conducted an experiment in order to grasp the mechanism of deterioration of flatness of the steel plate in the manufacturing process of the hot-rolled steel plate. FIG. 1 is a schematic diagram of manufacturing equipment after a finish rolling mill in a manufacturing process of a hot-rolled steel sheet. First, the hot-rolled steel sheet (hot-rolled steel sheet) 9 passes through the final stand 1 of the finish rolling mill and is guided by the standby side guide 7 at an opening degree that matches the rolled sheet width size in advance. After that, the temperature distribution in the width direction is measured by a thermometer 6, passed through a run-out table (ROT) 2, and is made into a predetermined material by a ROT cooling device 3 to make a predetermined plate temperature. And is passed through the pinch roll 4 and taken up in a coil shape by the down coiler 5.

  Although the steel plate temperature at the time of winding changes with the materials of a steel plate, it is 100-750 degreeC. The amount of camber that is a problem in the present invention is the amount of camber that is generated when the coil temperature is lowered to room temperature (normal atmospheric temperature in a factory) and the temperature of the entire steel plate becomes uniform at room temperature. is there. As described above, the amount of camber (rolling camber amount) due to the shape of the steel plate generated up to the final stand 1 of the finish rolling mill and the amount of camber (thermal strain camber amount) due to thermal strain caused by non-uniform cooling of the ROT cooling device. It is a superposition.

  However, as described above, the meandering amount and the rolling camber amount cannot be separated from the geometric camber amount obtained by measuring the camber amount of the steel sheet after rolling.

  Therefore, the present inventors have made the plate run-out behavior (the displacement in the plate width direction) of the steel plate installed before the pinch roll with respect to the plate passing behavior of the steel plate 6 up to the runout table 2, the pinch roll 4 and the down coiler 5 after rolling. 2) was measured with a displacement meter 8 or a camber meter, and as a result of examining the relationship between the telescopic amount of the coil, it was found that the lateral shake amount and the telescopic amount showed a strong positive correlation as shown in FIG.

Here, FIG. 8 shows a cross-sectional view of a hot-rolled coil for explaining the telescopic amount.
The telescopic amount is an amount of displacement when the coil is wound up so that the coil is slightly shifted and the telescope is extended.

  A rolling camber component and a meander component are mixed in the lateral runout measured with the displacement meter. On the other hand, since the telescopic amount corresponds to the camber amount of the steel sheet after winding, since the steel sheet imitates the pinch roll before the downcoiler, the bending and bending back effect is added, and the steel sheet is corrected. It was ascertained that the lateral vibration component due to was generated because it was plastically deformed and added to the rolling camber. That is, it has been found that the camber amount of the steel sheet after winding is the geometric camber amount immediately before winding.

  Based on this result, the lateral runout before the pinch roll was taken as the geometric camber amount, and the residual strain distribution generated during cooling was added to the thermal strain camber amount obtained by a predetermined thermal strain balance equation. The amount of camber of the steel plate when it became uniform was predicted.

  FIG. 12 shows the actual lateral vibration amount (denoted as the geometric lateral vibration amount in the figure) and the residual strain distribution generated during cooling by the thermal strain obtained by a predetermined thermal strain balance equation. The camber amount at normal temperature is predicted based on the shake amount (indicated as the thermal strain lateral shake amount in the figure).

  FIG. 12A simultaneously shows the actually measured lateral shake amount and the lateral shake amount due to thermal strain. Here, it is assumed that the amount of lateral vibration due to thermal strain is 0 mm in the coil TOP.

  FIG. 12B shows a lateral shake amount obtained by adding up the actually measured lateral shake amount and the lateral shake amount due to thermal strain. The camber amount is obtained for a length of 10 m with respect to the lateral shake amount. In the figure, the camber amount at the coil TOP is obtained.

  FIG.12 (c) shows the camber amount calculated | required by the method of FIG.12 (b). Since the camber can be defined after a predetermined length as a reference, the value of the camber amount starts from 10 m. The value of the camber amount is obtained after totaling the lateral shake amount actually measured in FIG. 12B and the lateral shake amount due to thermal strain. Each lateral shake amount is converted into a camber amount. Then, even if these are summed, the same FIG. 12C can be obtained.

  FIG. 4 shows a result of unwinding a plurality of coils and actually measuring the 10 m camber amount of each coil top portion as described above and comparing it with the predicted camber amount. Here, the data used as the camber amount is the value of the mark ● in FIG.

  From FIG. 4, it can be seen that the present invention for predicting the camber amount of the steel sheet after cooling from the thermostrictive camber amount and the geometric camber amount shows a very good agreement with the actual measurement result.

  On the other hand, FIG. 3 shows a result predicted only from the thermal strain, and FIG. 5 shows a result predicted only from the geometric camber measurement. It can be clearly seen that these values vary in the conventional methods of prediction only by thermal strain or geometric camber measurement.

  It was also found that the lateral camber amount measurement by the displacement meter can be obtained as the geometric camber amount with the same accuracy even if it is replaced with the camber obtained by the fixed point temperature measurement method. That is, the camber amount measured by the displacement meter 8 shown in FIG. 1 may be replaced with the camber amount measured by the thermometer 6.

The camber amount prediction of the front 10 m shown in FIG. 4 is an example, and in this prediction, it is also possible to predict the camber amount over the entire coil length. As an example, FIG. 6 shows a comparison between the camber amount measured over the entire coil length and the predicted camber amount. It turns out that it shows a very good agreement.
In response to such knowledge, the inventors have arrived at the invention described in (1).

  Next, (2) will be described. (1) ignores the effect of continuity in the width direction because the equation of thermal strain balance is a simple technique. Therefore, it is not a camber calculation by strict thermal strain. Therefore, it is possible to predict the camber amount with higher accuracy by solving the prediction of the camber amount due to thermal strain by the finite element method (FEM).

In the invention described in (3), the FEM analysis described in (2) is performed not only by bending analysis but also by large deflection analysis considering elastic wave buckling, so that thermal strain camber amount prediction considering out-of-plane deformation can be performed. It becomes possible to predict the camber amount with higher accuracy. As a result, in the prediction method described in (2), when there is a wave shape, the actual measurement and the prediction are deviated, and the correlation coefficient R ² = 0.983 as shown in FIG. When there is a wave shape by a large deflection analysis in consideration of bending, it is found that the correlation coefficient R ² = 0.9976 as shown in FIG.

  In the invention described in (4), the steel plate that passes through the heat treatment line is not limited to the size of the camber because the fracture occurs due to the request from the customer and the meandering caused by the camber in the FIPL which is the heat treatment line. It was necessary to go through the correction process, but using the accurate prediction of the camber amount described in (1), (2), (3), only the coil that was predicted to have a large camber amount was added to the refining process. This makes it possible to operate efficiently.

  The invention described in (5) can specify the position of how much camber amount is generated at which position in the accurate camber amount prediction described in (1), (2), (3) (see, for example, FIG. 5). ). If this predicted result is shown to the next process FIPL or the customer and the position where the camber that causes a problem is removed by shear cutting or the like is eliminated, the refining process itself is not increased.

Taking a manufacturing process of a hot-rolled steel sheet as an example, an example of performing flatness deterioration prediction of a metal plate and determining whether or not a plate can be passed through a refining process is shown. FIG. 1 is a schematic diagram of manufacturing equipment after a finish rolling mill in a manufacturing process of a hot-rolled steel sheet. First, the hot-rolled steel sheet 6 is rolled to a predetermined production size through a finishing final rolling mill 1, passed through a run-out table (ROT) 2, and made into a predetermined material up to a predetermined plate temperature by an ROT cooling device 3. While being cooled and preliminarily guided by the side guide 7 waiting at an opening corresponding to the width of the rolled sheet, the temperature distribution in the width direction is measured by the thermometer 6, and the lateral runout is measured by the displacement gauge 8 to measure the coiler 4. Is wound into a coil shape. The temperature of the plate to be wound varies depending on the material, but is up to 100 to 750 ° C. The flatness which is a problem in the present invention is that when the coil temperature is lowered to room temperature, unwinding at the center portion of the steel plate, the edge portion This is a case where a wavy out-of-plane deformation called an ear wave occurs.
At this time, thermal strain and thermal stress distribution were obtained using the cooled thermometer 6 and input to this model to predict the camber amount. With this prediction, it is possible to predict the camber amount over the entire coil length.

  However, practically, the amount of camber on the front 10 m and the tail 10 m of the coil becomes a problem. Therefore, the camber amount of the coil front 10 m and tail 10 m for 100 coils is predicted, and a coil having a camber amount exceeding 1σ (where σ is a standard deviation) as a predetermined criterion is passed through the refining process, and the camber is By correcting the amount, the plate breakage due to the camber at the time of passing through the continuous annealing equipment after hot rolling was 0%. As a result, the number of coils that had been completely trimmed so far was reduced by 66.6%.

  The predetermined criteria may be expanded to 2σ and 3σ according to the situation, or the criteria may be set according to past results.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  As described above, according to the present invention, the amount of camber at the normal temperature of the metal strip can be predicted with high accuracy, so the metal strip to be passed through the refining process and the correction process can be selected with high accuracy, and the cost can be reduced. As well as improving productivity. Therefore, the present invention contributes not only to the steel industry but also to the development of the metal working (rolling) industry.

1 Finishing mill final stand 2 ROT
3 ROT Cooling Device 4 Pinch Roll 5 Downcoiler 6 Thermometer 7 Side Guide 8 Displacement Meter 9 Steel Plate

Claims (5)

Metal manufactured by hot finish rolling to a predetermined production size, cooled to a predetermined plate temperature by a cooling device to be made into a predetermined material, bent and bent back by a pinch roll, and wound into a coil shape In the method for predicting the amount of camber at room temperature of the strip
Measure the surface temperature distribution of the steel sheet after runout table cooling with respect to the sheet width direction and the rolling direction,
Perform the balance calculation using the thermal strain at the time when the temperature distribution is then cooled and becomes uniform at room temperature, and determine the camber amount due to thermal strain,
Obtain the geometric camber amount measured from the amount of geometric camber obtained at the same time as the temperature measurement in the sheet width direction and rolling direction by the fixed point measurement method or the lateral runout amount provided by a separately installed displacement meter,
A method of predicting a camber amount at normal temperature of a metal strip, wherein the camber amount due to thermal strain and the geometric camber amount are overlapped.   2. The method of predicting a camber amount at normal temperature of a metal strip according to claim 1, wherein the camber amount due to the thermal strain is obtained by a finite element method (hereinafter also referred to as FEM) using the temperature distribution. Metal manufactured by hot finish rolling to a predetermined production size, cooled to a predetermined plate temperature by a cooling device to be made into a predetermined material, bent and bent back by a pinch roll, and wound into a coil shape In the method for predicting the amount of camber at room temperature of the strip
Measure the surface temperature distribution of the steel sheet after runout table cooling with respect to the sheet width direction and the rolling direction,
Obtain the camber amount considering the out-of-plane deformation of the steel sheet by the FEM large deflection analysis considering the wave buckling using the thermal strain when the temperature distribution is then cooled and becomes uniform at room temperature,
Obtain the geometric camber amount obtained simultaneously with the temperature measurement in the sheet width direction and rolling direction by the fixed point temperature measurement method,
A method of predicting a camber amount at normal temperature of a metal strip, wherein the camber amount due to thermal strain and the geometric camber amount are overlapped.   A method for producing a metal strip, characterized in that, when a predetermined criterion is exceeded, the metal strip is passed through a refining process using the method for predicting the amount of camber at normal temperature of the metal strip according to any one of claims 1 to 3.   Using the method for predicting the camber amount at normal temperature of the strip according to any one of claims 1 to 3, a region exceeding a predetermined criterion is stored, and when the strip is unwound in the next process, the criterion is exceeded. A method for producing a metal strip, wherein the region is shear-cut and the next plate is passed through.

Images