JP6311627B2 - Rolling mill control method, rolling mill control apparatus, and steel plate manufacturing method - Google Patents

Description

  The present invention relates to a rolling mill control method, a rolling mill control apparatus, and a steel plate manufacturing method.

  In general, in a hot rolling line, the horizontal bending of the material to be rolled due to various factors such as temperature deviation and plate thickness deviation in the width direction of the material to be rolled, and unevenness of the opening in the width direction of the rolling roll, so-called Camber is generated. Further, in a hot rolling line having a width press device, camber is generated due to temperature deviation in the width direction of the material to be rolled not only by rolling but also by width reduction. When the amount of camber of the material to be rolled is large, equipment such as rolling rolls and side guides may be damaged. On the other hand, when the amount of camber of the material to be rolled is small, the yield and quality of the product may be reduced.

  The temperature deviation in the width direction of the material to be rolled occurs mainly due to the influence of outside air cooling when the extraction door is opened and closed to extract the material to be rolled from the heating furnace. In addition, the temperature in the width direction of the material to be rolled is affected by the distance between adjacent materials to be rolled in the heating furnace, the dimensions of the material to be rolled, the furnace time of the material to be rolled, etc. It is difficult to heat the rolled material uniformly in the width direction. From such a background, Patent Documents 1 to 3 propose methods for suppressing the occurrence of camber on a material to be rolled. Specifically, Patent Document 1 proposes a method of measuring the temperature deviation in the width direction of the material to be rolled before rolling and performing leveling setting of the rolling mill based on the measured temperature deviation. Patent Document 2 proposes a method in which a camber meter is arranged on one side of a reversible rolling mill, and the leveling setting of the rolling mill in the next rolling pass is performed based on the camber amount measured by the camber meter. . Further, in Patent Document 3, a temperature deviation in the width direction of the material to be rolled is calculated from the measured camber amount, and the leveling of the rolling mill is calculated from a predetermined relationship between the temperature deviation in the width direction of the material to be rolled and the leveling amount. A method of setting is proposed.

JP 60-133904 A Japanese Patent No. 3584661 JP 2010-212230 A

  However, the method described in Patent Document 1 merely sets the leveling of the rolling mill in consideration of the difference in deformation resistance in the width direction due to the temperature deviation in the width direction of the material to be rolled before the start of rolling. It cannot be applied when the material to be rolled before the start of rolling has a camber. Further, the method described in Patent Document 2 cannot be applied to the first rolling pass. Further, since the temperature deviation in the width direction of the material to be rolled is not taken into consideration, it is insufficient for preventing camber. Furthermore, since the method described in Patent Document 3 does not consider camber generated in the width press apparatus, it cannot be applied to a hot rolling line having a width press apparatus in front of the rolling mill.

  This invention is made | formed in view of the said subject, The objective is the case where the to-be-rolled material before the rolling start has a camber, or the case where the width press apparatus is provided ahead of the rolling mill Even so, an object of the present invention is to provide a control method for a rolling mill, a control device for the rolling mill, and a method for manufacturing a steel plate that can suppress the occurrence of camber on the material to be rolled by setting the leveling amount appropriately.

  A rolling mill control method according to the present invention is a rolling mill control method when rolling a heated rolled material with a rolling mill after the width of the rolled material is reduced by a width press device, and the rolling material is controlled in the width direction of the rolled material. A control step of calculating the leveling amount of the rolling mill based on the temperature deviation, the width of the material to be rolled before width reduction, and the width reduction amount of the material to be rolled, and controlling the rolling mill based on the calculated leveling amount. It is characterized by including.

  The rolling mill control method according to the present invention is the above invention, wherein in the control step, the temperature deviation in the width direction of the material to be rolled is ΔT, the width of the material to be rolled before width reduction is W, and the width reduction of the material to be rolled is reduced. When the amount is ΔW, the method includes a step of calculating the leveling amount ΔS of the rolling mill using the following formula (1).

  Here, the parameters α and β in the formula (1) represent the tuning rate.

  A rolling mill control device according to the present invention is a rolling mill control device for rolling a heated rolled material with a rolling mill after the width of the rolled material is reduced by a width press device, the rolling device controlling the width of the rolled material Control means for calculating the leveling amount of the rolling mill based on the temperature deviation, the width of the material to be rolled before width reduction, and the width reduction amount of the material to be rolled, and controlling the rolling mill based on the calculated leveling amount It is characterized by providing.

  A method for manufacturing a steel sheet according to the present invention is a method for manufacturing a steel sheet by manufacturing a steel sheet by rolling the heated material to be rolled with a width press and then rolling with a rolling mill, wherein the width of the material to be rolled is The leveling amount of the rolling mill is calculated based on the temperature deviation in the direction, the width of the material to be rolled before width reduction, and the width reduction amount of the material to be rolled, and the rolling mill is controlled based on the calculated leveling amount. A control step is included.

  According to the rolling mill control method, rolling mill control apparatus, and steel plate manufacturing method according to the present invention, when the material to be rolled before the start of rolling has a camber, a width press apparatus is provided in front of the rolling mill. Even if it is provided, it is possible to suppress the occurrence of camber on the material to be rolled.

FIG. 1 is a schematic diagram showing a configuration of a hot rolling line to which a rolling mill control apparatus according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram showing a configuration of a rolling mill control apparatus according to an embodiment of the present invention. FIG. 3 is a schematic diagram for explaining the definition of the leveling setting amount. FIG. 4 is a schematic diagram for explaining the definition of the camber amount. FIG. 5 is a diagram showing the camber amount in the present invention example and the conventional example. FIG. 6 is a diagram showing the camber amount in the present invention example and the conventional example.

  Hereinafter, a control device for a rolling mill according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of hot rolling line]
First, with reference to FIG. 1, the structure of the hot rolling line to which the control apparatus of the rolling mill which is one Embodiment of this invention is applied is demonstrated.

  FIG. 1 is a schematic diagram showing a configuration of a hot rolling line to which a rolling mill control apparatus according to an embodiment of the present invention is applied. As shown in FIG. 1, a hot rolling line 1 to which a rolling mill control device according to an embodiment of the present invention is applied includes a heating furnace 2 and a width press device in order from the upstream side in the transport direction of the material S to be rolled. 3, a rough rolling mill 4, a finish rolling mill 5, a run-out table 6, a water cooling device 7, and a coiler 8.

  In this hot rolling line 1, first, the material to be rolled S heated in the heating furnace 2 is reduced in width by the width press device 3, and then usually has a predetermined thickness by about 2 to 5 rough rolling machines 4. Until rolled. Next, the material to be rolled S rolled by the roughing mill 4 is further thinly rolled by the finish rolling mill 5 and then water-cooled by the water-cooling device 7 while passing through the run-out table 6, and coiled by the coiler 8. Rolled up. And the coil-shaped to-be-rolled material S is cooled to normal temperature in a coil yard.

  In such a hot rolling line 1, the horizontal direction of the material S to be rolled due to various factors such as temperature deviation and thickness deviation in the width direction of the material S to be rolled, and unevenness of the opening in the width direction of the rolling roll. Bend, so-called camber occurs. When the amount of the camber of the material S to be rolled is large, equipment such as rolling rolls and side guides may be damaged. In addition, when the amount of camber generated by rough rolling is large, when the tail end of the material to be rolled S falls off in the finish rolling mill 5, the material to be rolled S collides with the side guide and the edge portion is broken. Rolling trouble called so-called “squeezing”, which is rolled in a squeezed state, may occur.

  The factors that cause camber in the rough rolling mill 4 are mainly a temperature deviation in the width direction of the material to be rolled S and a poor leveling setting. The deformation resistance on the high temperature side of the temperature in the width direction of the material S to be rolled is smaller than the deformation resistance on the low temperature side. For this reason, a rolling load distribution is generated in the width direction of the material S to be rolled during rough rolling, and the roll gap on the high temperature side is reduced and the reduction amount is increased, thereby generating camber.

  In general, when there is no sheet thickness deviation or camber in the width direction of the material to be rolled S on the entry side of the rough rolling mill 4, the high temperature side of the temperature in the width direction of the material to be rolled S is further extended. Turn to the lower temperature side. Also in the width press apparatus 3, camber is generated due to the temperature deviation in the width direction of the material S to be rolled. Specifically, since the deformation resistance is small on the high temperature side of the width direction temperature, the width reduction amount is larger than that on the low temperature side, resulting in a difference in elongation in the longitudinal direction. And since the high temperature side of the width direction temperature is extended similarly to the time of rough rolling, the to-be-rolled material S bends to the low temperature side.

  As a result of intensive studies, the inventors of the present invention have found that the amount of camber generated in the width press device 3 is larger as the temperature deviation in the width direction is larger and the width reduction amount is larger. In addition, the inventors of the present invention have found that the smaller the width of the material S to be rolled before width reduction, the larger the amount of camber generated in the width press device 3. The inventors of the present invention indicate that, even if the temperature deviation in the width direction is the same, the smaller the width of the material S to be rolled, the larger the temperature deviation per unit width, and the larger the camber amount per unit width. I thought it would be.

  In general, since the mold of the width press apparatus 3 is driven symmetrically, it is difficult to completely prevent the occurrence of camber in the width press apparatus 3 even if there is a temperature deviation in the width direction. Therefore, the inventors of the present invention conceived to suppress the occurrence of camber by correcting the camber in the rough rolling step after width reduction. That is, until now, since the leveling amount of the subsequent rough rolling process was set without considering the camber generated by the width reduction, the camber control was insufficient. On the other hand, in the present invention, the leveling amount in the rough rolling process is set by simultaneously considering the camber generated by the width reduction and the temperature deviation in the width direction.

[Configuration of control device]
Next, with reference to FIG. 2, the structure of the control apparatus of the rolling mill which is one embodiment of this invention conceived based on the said technical thought is demonstrated.

  FIG. 2 is a schematic diagram showing a configuration of a rolling mill control apparatus according to an embodiment of the present invention. As shown in FIG. 2, the rolling mill control device 10 according to an embodiment of the present invention includes a thermometer 11, a leveling amount setting unit 12, and a reduction control unit 13.

  The thermometer 11 is provided in a hot rolling line between the heating furnace 2 and the width press apparatus 3 and measures a temperature deviation ΔT in the width direction of the material S to be rolled. The thermometer 11 outputs an electrical signal indicating the measured temperature deviation ΔT in the width direction of the material to be rolled S to the leveling amount setting unit 12. Note that the temperature deviation ΔT in the width direction of the material to be rolled S is preferably measured on the upstream side of the width press apparatus 3 and may be defined as the surface temperature difference between both ends in the width direction.

  Moreover, when the temperature of the width direction edge part cannot be measured correctly, you may substitute the temperature inside 100 mm inside from the width direction edge part, for example. For example, a radiation thermometer such as a thermoviewer can be used as the thermometer 11, but the present invention is not limited to the measurement method. Needless to say, the present invention can be applied by measuring the temperature of the material to be rolled S even in the case of direct feed rolling in which rolling is performed from a continuous casting machine without passing through the heating furnace 2.

  The leveling amount setting unit 12 includes a temperature deviation ΔT in the width direction of the material to be rolled S output from the thermometer 11, a width W of the material to be rolled S for performing the width reduction acquired from the width press device 3, and a width reduction amount ΔW. Is substituted into the following formula (1) to calculate the leveling set amount (roll reduction position difference) ΔS of the roughing mill 4. The leveling amount setting unit 12 outputs an electric signal indicating the calculated leveling setting amount ΔS of the roughing mill 4 to the reduction control unit 13.

  Here, the parameters α and β in the formula (1) represent the tuning rate. The tuning rate α can be determined according to the rolling load, the reduction rate, and the number of rollings. The tuning rate β is an index indicating the ease of occurrence of camber due to the temperature deviation in the width direction in the width press device 3, and the opening degree of the side guide and the rolling force of the upper and lower restraining rolls on the exit side of the width press device 3. Can be determined according to

  Further, the leveling set amount ΔS means a reduction position difference between the driving side and the working side of the rolling roll 4a constituting the rough rolling mill 4, as shown in FIG. The temperature deviation ΔT in the width direction of the material S to be rolled and the leveling set amount ΔS of the roughing mill 4 are both defined as a difference obtained by subtracting the other value from one value on the driving side or the working side. In addition, the drive side means the width direction end part side of the rolling roll to which the roll driving motor is attached, and the work side means the width direction end part side of the rolling roll on the opposite side to the drive side. .

  The reduction control unit 13 controls the reduction positions on the drive side and work side of the roughing mill 4 according to the leveling set amount ΔS output from the leveling amount setting unit 12. Since the temperature deviation ΔT in the width direction of the material to be rolled S is large, the width reduction amount ΔW is large, and the width W of the material to be rolled S is small, the amount of camber generated by the width reduction becomes large. In order to correct, it is necessary to set the leveling amount of the roughing mill 4 large. The leveling set amount ΔS is obtained by correcting the camber generated by the width reduction and the occurrence of camber due to the rough rolling due to the temperature deviation in the width direction by widening the rolling roll opening on the high temperature side of the width direction temperature of the material S to be rolled. Suppress. Further, with respect to the material to be rolled S that is not subjected to width reduction by the width press device 3, the occurrence of camber due to rough rolling can be suppressed by considering only the temperature deviation in the width direction of the material to be rolled S with the width reduction amount ΔW being zero.

  As is apparent from the above description, the rolling mill control device 10 according to an embodiment of the present invention includes a temperature deviation ΔT in the width direction of the material to be rolled S, a width W of the material to be rolled S before width reduction, and Since the leveling set amount ΔS of the rough rolling mill 4 is calculated based on the width reduction amount ΔW of the material S to be rolled, and the rough rolling mill 4 is controlled based on the calculated leveling set amount ΔS, the roll before rolling is started. Even when the material S has a camber or when the width press device 3 is provided in front of the rough rolling mill 4, the occurrence of the camber on the material to be rolled S can be suppressed.

[Example 1]
In this example, 1231 rolled materials of mild steel having a length of 7000 to 10000 mm, a thickness of 250 mm, and a width of 800 to 1500 mm were heated to 1200 to 1250 ° C. in a heating furnace, and subjected to rough rolling after being reduced in width by a width press device. went. The width reduction amount was 0 to 300 mm, and the reduction amount in rough rolling was 30 to 40 mm in the first pass. A two-high rolling mill having a work roll diameter of 1500 mm was used as the rough rolling mill.

  The amount of camber after one pass of rough rolling was measured with a camber meter temporarily provided on the delivery side of the roughing mill. The camber amount was measured as a bending in the longitudinal direction by a CCD camera and image processing. That is, as shown in FIG. 4, the camber amount ΔC was defined as a deviation of the longitudinal center position in the longitudinal direction with respect to the straight line L <b> 1 that connects the center positions in the width direction of the rolled material S. In the example of the present invention, the leveling amounts of the roughing mill were controlled using Equation (1) with the values of the tuning rates α and β being 0.01 and 0.5, respectively. On the other hand, in the conventional example, leveling is performed without considering the camber due to the width reduction by setting the value of the tuning rate β in the mathematical formula (1) to 0.0 with respect to the rolled material having substantially the same size. The amount was controlled. Furthermore, rolling was performed while keeping the leveling amount of the roughing mill constant, and the variation of the camber amount in that case was also confirmed.

  FIG. 5 shows the amount of camber after one pass of rough rolling. As shown in FIG. 5 (b), in the conventional example, when the camber amount exceeded 105 mm, a plate passing trouble occurred. On the other hand, in the present invention example, the camber amount could be controlled within 100 mm. In addition, the standard deviation (σ) of the camber amount in the example of the present invention was 38 mm, whereas the standard deviation (σ) of the camber amount in the conventional example is 62 mm. It was confirmed that it can be reduced by 39%. When the leveling amount of the roughing mill was constant, the standard deviation of the camber amount was 92 mm.

[Example 2]
In this example, 1231 rolled materials of mild steel having a length of 7000 to 10000 mm, a thickness of 275 mm, and a width of 800 to 1400 mm were heated to 1200 to 1250 ° C. in a heating furnace, and subjected to rough rolling after being reduced in width by a width press device. went. As a rough rolling mill, a reversible two-stage rolling mill having a work roll diameter of 1500 mm was used. The first roughing mill performed three-pass rolling, and the amount of camber after the third pass was measured.

  In the present invention example, the leveling amount of the roughing mill was controlled using Equation (1) with the values of the tuning rates α and β being 0.005 and 0.5, respectively. On the other hand, in the conventional example, by setting the value of the tuning rate β in the mathematical formula (1) to 0.0 with respect to the rolled material having substantially the same dimensions, the camber due to the width reduction is not considered. The leveling amount of the rolling mill was controlled. Further, rolling was performed while keeping the leveling amount of the roughing mill constant, and the variation in the camber amount in that case was confirmed. FIG. 6 shows the amount of camber after 3 passes of rough rolling. As shown in FIG. 6, the standard deviation (σ) of the camber amount in the example of the present invention was 42 mm, whereas the standard deviation (σ) of the camber amount in the conventional example was 65 mm. It was confirmed that the variation in the thickness can be reduced by about 35%.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Hot rolling line 2 Heating furnace 3 Width press apparatus 4 Rough rolling mill 5 Finish rolling mill 6 Runout table 7 Water cooling apparatus 8 Coiler 10 Control apparatus 11 Thermometer 12 Leveling amount setting part 13 Reduction control part S Rolling material

Claims (4)

A method for controlling a rolling mill when rolling a heated material to be rolled with a rolling mill after width reduction with a width press device,
The temperature deviation in the width direction of the material to be rolled before width reduction is large, the width of the material to be rolled before width reduction is small, and the leveling amount of the rolling mill increases as the width reduction amount of the material to be rolled increases. The leveling amount of the rolling mill is calculated based on the temperature deviation in the width direction of the material to be rolled before width reduction, the width of the material to be rolled before width reduction , and the width reduction amount of the material to be rolled. A control method for a rolling mill, comprising a control step for controlling the rolling mill based on a quantity. In the control step, when the temperature deviation in the width direction of the material to be rolled before width reduction is ΔT, the width of the material to be rolled before width reduction is W, and the width reduction amount of the material to be rolled is ΔW, The method for controlling a rolling mill according to claim 1, comprising a step of calculating the leveling amount ΔS using the following formula (1).

Here, the parameters α and β in the formula (1) represent the tuning rate. A rolling mill control device for rolling a heated material to be rolled with a rolling mill after width reduction with a width press device,
The temperature deviation in the width direction of the material to be rolled before width reduction is large, the width of the material to be rolled before width reduction is small, and the leveling amount of the rolling mill increases as the width reduction amount of the material to be rolled increases. The leveling amount of the rolling mill is calculated based on the temperature deviation in the width direction of the material to be rolled before width reduction, the width of the material to be rolled before width reduction , and the width reduction amount of the material to be rolled. A control device for a rolling mill, comprising control means for controlling the rolling mill based on a quantity. A method of manufacturing a steel sheet, in which a steel sheet is manufactured by rolling with a rolling mill after width reduction of a heated material to be rolled by a width press device,
The temperature deviation in the width direction of the material to be rolled before width reduction is large, the width of the material to be rolled before width reduction is small, and the leveling amount of the rolling mill increases as the width reduction amount of the material to be rolled increases. The leveling amount of the rolling mill is calculated based on the temperature deviation in the width direction of the material to be rolled before width reduction, the width of the material to be rolled before width reduction , and the width reduction amount of the material to be rolled. The manufacturing method of the steel plate characterized by including the control step which controls the said rolling mill based on quantity.

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