JP5949691B2 - Plate width control method and plate width control device - Google Patents

Description

  The present invention relates to a sheet width control method and a sheet width control apparatus for a material to be rolled in a hot rough rolling process in which vertical and horizontal rough rolling is performed.

  In the hot rolling process of a steel plate, a sheet bar having a thickness of about 40 [mm] is manufactured from a slab having a thickness of about 250 [mm] and a width of about 800 to 2000 [mm] by a rough rolling process. The sheet bar is wound by a coiler after being rolled to a desired product thickness or a sheet thickness of about 1 to 20 [mm] required in the next process by a finish rolling process. The rough rolling process and the finish rolling process are each performed using a rolling mill group including a plurality of rolling mills. Also, in the hot rolling process of steel plates, it is necessary to control the plate width in addition to the plate thickness of the steel plate so that it becomes the target plate width, and the plate width control of the steel plate is performed in the rough rolling process and the finish rolling process. Yes.

  In the plate width control in the rough rolling process, a sizing press (hereinafter referred to as a press device) having a pair of press tools for reducing the width of the slab in the plate width direction using a die and an edger (coffin roll) are used. A method of reducing the slab heated in the heating furnace in the plate width direction is employed. On the other hand, in the plate width control in the finish rolling process, the width reduction amount of the sheet bar between the entry side and the exit side of the finish rolling process is performed by manipulating the tension applied to the sheet bar between a plurality of rolling mills. The method of controlling is adopted.

  However, the sheet width control ability of the sheet width control method employed in the finish rolling process is smaller than the sheet width control ability of the sheet width control method employed in the rough rolling process. For this reason, the operation | work which changes the board width of a steel plate largely serves as the role of a rough rolling process. In particular, the pressing device can significantly reduce the slab compared to the edger. As a result, wide materials are aggregated and cast in the continuous casting process, and steel sheets having various sheet widths are separately formed in the hot rolling process.

  The cross-sectional shape of the slab after the width reduction by the press device is a so-called dogbone shape in which the end in the width direction is raised in the plate thickness direction. This dogbone shape is smoothed by subsequent horizontal rolling, resulting in a width return. Since the material easily flows in the longitudinal direction at the leading end portion of the slab, the width return amount is smaller than that in the steady portion. For this reason, a phenomenon that the plate width of the leading end portion of the slab after horizontal rolling becomes narrower than the plate width of the steady portion, so-called width drop occurs. Once the width drop occurs, it is difficult to recover the plate width by subsequent plate width control. As a result, a reduction in the width of the coil wound by the coiler remains, and when the plate width is less than the desired plate width, it is discarded, resulting in a yield loss.

  From such a background, in order to suppress the occurrence of a drop in width, Patent Document 1 discloses that a steady portion according to a difference in width return amount between a slab tip rear end portion and a steady portion during subsequent horizontal rolling. There has been proposed a plate width control method (hereinafter referred to as a step press) for controlling the width reduction amount of the slab tip and / or tail end by a press device so that the width becomes wider with respect to the width reduction amount. Further, in Patent Document 2, after performing width reduction by a press device so that at least one of the slab leading and trailing ends has a reduction amount difference α as compared with the steady portion, at least in the first pass of the roughing mill A sheet width control method has been proposed in which vertical rolling of at least one of the slab tail ends is performed with a reduction amount β.

JP-A 63-140701 JP 2002-361301 A

  Generally, in the rough rolling process, the slab passes through the horizontal mill after passing through the edger. However, Patent Document 1 does not disclose a setting method and a control method of the opening degree of the edger in the first pass of the rough rolling process. On the other hand, buckling or twisting may occur in the slab under width pressure by a press device. When the slab is buckled or twisted, the substantial width reduction amount becomes small, and the width of the slab on the exit side of the press apparatus may be wider than that assumed from the width reduction amount by the press apparatus.

  In Patent Document 2, it is proposed that the width reduction amount of the edger of the first pass of the slab leading end is β, but the width of the slab on the outlet side of the press device due to buckling or twisting is expected. When the width of the slab becomes wider, the width reduction amount of the edger in the first pass with respect to the slab leading end becomes larger than the setting. In this case, the leading end of the slab whose width has been widened in advance by the pressing device is greatly reduced by the width of the edger in the first pass, and the width of the leading end is widened in the pressing device to prevent width drop. The effect of the step press is impaired.

  In addition, when the leading end, which is wider than the stationary part in the press device, is lightly lowered by the edger, the edger is not applied at all in the stationary part having a smaller width. In this case, since the slab is not constrained in the lateral direction (direction perpendicular to the rolling direction) by the edger, the slab enters the horizontal roll in a direction inclined with respect to the rolling direction during the horizontal rolling, and the horizontal rolling exit side The slab may bend in the horizontal direction.

  The present invention has been made in view of the above problems, and its purpose is to control the plate width that can suppress the effect of the step press when the width of the slab on the outlet side of the press device is not a predetermined value. It is to provide a method and a plate width control apparatus.

  The sheet width control method according to the present invention uses an edger and a roughing mill after the slab heated by making the width reduction amount of the front end portion smaller than the width reduction amount of the stationary portion is reduced using a pressing device. A sheet width control method in a hot rough rolling process for performing rough rolling in the vertical direction and horizontal direction of a slab, measuring a step of measuring a width of a tip portion of the slab on the exit side of the press device, And a control step of controlling the opening degree of the edger in the first pass of the rough rolling based on the width of the front end portion of the slab.

  In the sheet width control method according to the present invention, in the above invention, after the control step, the opening degree of the edger in the first pass of the rough rolling is set to be equal to the measured width of the tip portion of the slab. The step of controlling the opening degree of the edger so that the rolling load of the edger becomes substantially constant during rough rolling is characterized.

  In the sheet width control method according to the present invention, in the above invention, the control step controls the opening degree of the edger based on the width of the slab measured over the entire length on the exit side of the press device during rough rolling. Including steps.

  The sheet width control device according to the present invention uses an edger and a rough rolling mill after width-squeezing a heated slab by using a pressing device so that the width reduction amount of the tip portion is smaller than the width reduction amount of the stationary part. A sheet width control device in a hot rough rolling process for performing rough rolling in the vertical direction and horizontal direction of the slab, and measuring means for measuring the width of the tip portion of the slab on the exit side of the press device. And a control means for controlling the opening degree of the edger in the first pass of the rough rolling based on the width of the tip of the slab.

  According to the plate width control method and the plate width control device according to the present invention, it is possible to suppress the effect of the step press from being impaired when the width of the slab on the outlet side of the press device is not a predetermined value.

FIG. 1 is a schematic diagram showing a configuration of a hot rolling line to which a sheet width control apparatus according to an embodiment of the present invention is applied. FIG. 2 is a block diagram showing a configuration of a plate width control apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a change in the slab width on the exit side of the rough rolling mill when the plate width control method of the present embodiment and the conventional plate width control method are carried out. FIG. 4 is a diagram showing a change in the slab width on the exit side of the rough rolling mill when the plate width control method of the present embodiment and the conventional plate width control method are carried out. FIG. 5 is a diagram illustrating target widths of the leading end portion and the stationary portion of the slab on the exit side of the press device.

  Hereinafter, the configuration of a plate width control apparatus 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 sheet | seat width control apparatus 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 sheet width 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 sheet width control device according to an embodiment of the present invention is applied includes three rough rolling mills 3 a, 3 b, which perform horizontal rolling downstream of a pressing device 2. 3c (R1, R2, R3) has the structure arrange | positioned in series with respect to the conveyance direction of the slab S. Further, edgers 5a, 5b, and 5c (E1, E2, and E3) for performing vertical rolling are attached to the upstream sides of the rough rolling mills 3a, 3b, and 3c, respectively. The slab S that has been subjected to width reduction in the pressing device 2 is sequentially conveyed to the edgers 5a, 5b, and 5c and the roughing mills 3a, 3b, and 3c by the table roller 4 to be vertically and horizontally rolled. In the rough rolling process, in order to obtain a reduction amount from the thickness of the slab S to the finishing mill entry side, the slab S may be reciprocated and rolled in multiple passes.

[Configuration of plate width controller]
Next, with reference to FIG. 2, the structure of the board width control apparatus which is one Embodiment of this invention is demonstrated.

  FIG. 2 is a block diagram showing a configuration of a plate width control apparatus according to an embodiment of the present invention. As shown in FIG. 2, a plate width control device 10 according to an embodiment of the present invention includes an operation computer (process computer) 11, a press exit side width meter 12, a load measuring device 13, an opening degree control device 14, and A hydraulic servo device 15 is provided as a main component.

  The operation computer 11 is constituted by an information processing device such as a personal computer or a workstation, and manages and controls the hot rolling line 1 shown in FIG. The operation computer 11 controls the setting timing of the edger opening so that the roll position of the edger 5a (hereinafter referred to as the edger opening) is set before the slab S reaches the edger 5a.

  The press exit width meter 12 is constituted by a laser distance meter. The press exit side width meter 12 measures the width of the slab tip portion that has been subjected to width reduction by the press device 2 shown in FIG. 1, and inputs the measured value to the opening degree control device 14. As a method for measuring the width of the slab S, laser distance meters are installed on both sides of the slab S in the width direction, the distances from the laser distance meters to the slab side surfaces are calculated, and each laser is determined from the distance between the two laser distance meters. A method of subtracting the sum of distances from the distance meter to the slab side, a linear light source is installed below the slab S, and an image of the slab S is taken from above using a CCD camera or the like. A method of detecting the end of the slab width direction by detecting the position of the blocked light source. The self-light emission of the slab S is captured by a CCD camera or the like without using the light source, and the end of the slab width direction is detected from the photographed image. A method or the like can be used.

  The load measuring device 13 measures the rolling load of the edger 5 a and inputs the measured value to the opening degree control device 14.

  The opening control device 14 calculates a target value (target opening) of the edger opening based on the measured value of the press exit width meter 12, and inputs the calculated target opening to the hydraulic servo device 15. Specifically, in the present embodiment, the opening degree control device 14 sets the target opening degree so that the edger opening degree becomes equal to the width of the slab tip portion measured by the press exit side width meter 12, and the target opening degree is set. The opening is held over the entire length of the slab S. However, in order to reliably restrain the slab by the edger 5a even if the plate width of the slab S fluctuates, the target opening is obtained by subtracting a constant value (about 0 to several mm) from the measured value of the press exit side width meter 12. It is good.

  The hydraulic servo device 15 adjusts the edger opening to the target opening input from the opening controller 14.

[Plate width control processing]
Next, with reference to FIG. 3 thru | or FIG. 5, the board width control method by the board width control apparatus 10 which is one Embodiment of this invention is demonstrated.

  3 and 4 show the change in the slab width on the exit side of the rough rolling mill 3a (R1) when the sheet width control method of the present embodiment and the conventional sheet width control method are carried out, based on the slab width of the stationary part. FIG. In the conventional plate width control method, the target opening of the edger 5a is set so that the width reduction amount of the edger 5a with respect to the slab tip is 0 [mm], and the target opening is held over the entire length of the slab. It was. Further, as shown in FIG. 5, a step press is applied to the leading end portion of the slab so that the plate width is 20 [mm] wider than the plate width of the steady portion, and the exit side of the press device 2 The target widths of the leading end portion and the stationary portion of the slab at 10 are set to 1020 [mm] and 1000 [mm], respectively.

  FIG. 3 shows the change of the slab width on the exit side of the rough rolling mill 3a (R1) when the slab width on the exit side of the press apparatus 2 is as the target value (1020 [mm]). It is shown in the standard. In both of the present embodiment and the conventional plate width control method, the target opening degree of the edger 5a is 1020 [mm], and therefore the width reduction by the edger 5a is not performed over the entire length. For this reason, the difference between the slab width on the exit side of the press device 2 and the slab width on the exit side of the rough rolling mill 3a (R1) is only the amount of width spread accompanying horizontal rolling by the rough rolling mill 3a (R1), There is no difference in rolling results between the sheet width control method of the present embodiment and the conventional sheet width control method.

  FIG. 4 shows a case where the slab width on the exit side of the press apparatus 2 is 20 [mm] wider than the target value due to buckling or twisting of the slab, that is, the slab width is 1040 [mm] at the leading end, The change in the slab width on the exit side of the rough rolling mill 3a (R1) when 1020 [mm] is obtained. In the conventional plate width control method, since the target opening degree of the edger 5a is 1020 [mm], the width reduction amount is 0 (= 1020-1020) [mm] in the steady portion, and there is no influence. However, at the leading end, the width reduction amount is 20 (= 1040-1020) [mm], and on the exit side of the edger 5a, the plate width is 1020 [mm] for both the leading end and the steady portion.

  Then, in the horizontal rolling by the rough rolling mill 3a (R1), the thickness direction rise generated at the width direction end portion of the slab S due to the width reduction by the press device 2 and the edger 5a, that is, the dog bone has a width A width return spreads in the direction. When 1- (width return amount / width reduction amount) is defined as width reduction efficiency, and the value is 0.5, the plate width between the leading end portion and the steady portion on the exit side of the rough rolling mill 3a (R1) Is reduced from 20 [mm] to 10 [mm], and the step press amount is halved.

  As shown in FIG. 3 and FIG. 4, a width drop of 5 to 6 [mm] occurs at the leading end on the exit side of the rough rolling mill 3a (R1). In the rough rolling mills 3b and 3c (R2, R3), the width is further reduced. Therefore, in the conventional sheet width control method, the width of the tip is narrower than the width of the steady portion. And when the width | variety of a front-end | tip part is less than the product width | variety, it will become a width defect, and since it will be necessary to discard a defective part, a yield falls.

  In general, in the hot rolling process, the target width is obtained by adding a certain margin to the product width so that width defects do not occur. However, in the conventional sheet width control method, it is necessary to increase this margin. It becomes a factor of the yield fall. Similarly, when the slab exit side width is wider than the target value than in the case shown in FIG. 4, half of the difference in the amount of reduction between the leading end and the steady portion is the roughing mill 3a (R1). This is the difference in the plate width between the leading end portion and the steady portion on the exit side of the sheet, and in this case, it is 10 [mm], so the amount of the step press is halved.

  On the other hand, in this embodiment, the target opening degree of the edger 5a is set based on the measured value of the width of the slab tip on the exit side of the press device 2. For this reason, when the slab width on the outlet side of the press apparatus 2 is 20 [mm] wider than the target value, that is, the plate widths are 1040 [mm] and 1020 [mm] at the leading end portion and the steady portion, respectively. In this case, the target opening degree of the edger 5a is set to 1040 [mm].

  For this reason, the width reduction amount at the leading end of the slab S is 0 [mm], and the width reduction is not performed, so the effect of the step press is not impaired. Even when the slab width on the exit side of the press device 2 is widened or conversely narrowed for some reason, the target opening of the edger 5a is always the slab tip on the exit side of the press device 2. Since it is set equal to the width, the effect of the step press does not change from the case where the width of the slab on the exit side of the press device 2 is the target value.

  In this embodiment, the target opening of the edger 5a is set so that the width reduction amount of the edger 5a with respect to the slab tip is 0 [mm], and the target opening is held over the entire length of the slab. However, in this case, the edger 5a is not applied at all in the stationary part. When the edger 5a is not applied at all, since the slab S is not restrained in the lateral direction by the edger 5a, the slab S enters the horizontal roll in a direction inclined with respect to the rolling direction during the horizontal rolling. There is a possibility that the slab S will bend in the lateral direction on the rolling exit side.

  Therefore, after setting the target opening of the edger 5a to be equal to the measured value of the width of the slab tip on the exit side of the press device 2, the edger opening is adjusted so that the rolling load of the edger 5a is substantially constant. You may make it do. Specifically, the actual value of the rolling load of the edger 5a measured by the load measuring device 13 is compared with the target value, and the edger opening is adjusted by PI control based on the deviation between the actual value and the target value. Also good. Thereby, the position of the roll of the edger 5a is controlled to follow the slab end face.

  In the pressing step, since the slab S is compressed in the width direction by the mold while the slab S is moved intermittently, unevenness is generated at the end of the slab S. For this reason, even if the above control is performed, the rolling load of the edger 5a does not become completely constant, but the purpose of this control is to restrain the slab S by the edger 5a, so the rolling load of the edger 5a is substantially constant. If it is. The target value of the rolling load of the edger 5a may be determined so that the width reduction does not occur or is a slight one within several millimeters, and is usually within several tons.

  In order to align the edger 5a with the end face of the slab, the width of the slab S on the exit side of the press device 2 is measured over the entire length using the press exit width meter 12, and the opening angle of the edger according to the measured width May be controlled. Also in this case, the roll of the edger 5a does not need to be accurately made to the unevenness of the slab end face, and the roll of the edger 5a may follow the slab end face substantially.

  In this method, the longitudinal position of the slab S on the exit side of the press device 2 and the width at each longitudinal position are stored in correspondence with each other, and the width at that position with respect to the material under the roll bite of the edger 5a is stored. It is necessary to control the edger opening based on this. For this purpose, means for identifying the longitudinal position of the slab S at each position of the press exit width meter 12 and the edger 5a, that is, tracking means is required.

  As the tracking means, for example, a pulse generator connected to a table roller that conveys the slab S is used to generate pulses at a certain rotation angle, and the generated pulses are counted to convert the length, and from above the slab S. A measuring roll is brought into contact, a pulse generator connected to it generates pulses at a certain rotation angle, and the pulses are counted to convert them into lengths. The speed of the slab S is measured with a laser Doppler velocimeter. In the edger 5a, the measured value is integrated and converted into a length. In the edger 5a, a pulse is generated by a pulse generator connected to the edger 5a at every fixed rotation angle, and the length is converted by counting the pulses. A known technique such as a method can be used.

  In this embodiment, the speed of the slab S in the press exit width meter 12 is measured using a method of connecting a pulse generator to the table roller, and the slab is started from the rise timing of the measured value in the press exit width meter 12. By integrating the velocity of S, the longitudinal position of the slab S at that position was obtained, and this was associated with the measured value of the width at the delivery side of the press. Further, in the edger 5a, the current position in the longitudinal direction of the slab S is obtained by integrating the speed of the slab S starting from the rise timing of the rolling load of the edger 5a, and the edger opening degree is determined based on the corresponding width. Controlled.

  The embodiment to which the invention made by the present inventors is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. For example, although this embodiment applies this invention to the front-end | tip part of the slab S, this invention can be applied similarly to the tail end part of the slab S. As described above, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Hot rolling line 2 Press apparatus 3a, 3b, 3c Rough rolling mill 4 Table roller 5a, 5b, 5c Edger 10 Sheet width controller 11 Operation computer (process computer)
12 Press exit width meter 13 Load measuring device 14 Opening control device 15 Hydraulic servo device

Claims (3)

After pressing the slab heated by making the width reduction amount of the tip part smaller than the width reduction amount of the steady part using a press device, the slab vertical and horizontal roughing using an edger and a rough rolling mill. A sheet width control method in a hot rough rolling process in which rolling is performed,
A measuring step for measuring the width of the tip of the slab on the exit side of the pressing device;
A control step of controlling the opening of the edger in the first pass of the rough rolling to be equal to the measured width of the tip of the slab , and
In the control step, after the opening degree of the edger in the first pass of the rough rolling is controlled to be equal to the measured width of the tip of the slab, the edger follows the end face of the steady part of the slab. The board width control method characterized by including the step which controls the opening degree of an edger . The control step includes a step of controlling the opening degree of the edger based on the rolling load of the edger or the width of the slab measured on the exit side of the press device so that the edger follows the end face of the stationary part of the slab. The board width control method according to claim 1, further comprising: After pressing the slab heated by making the width reduction amount of the tip part smaller than the width reduction amount of the steady part using a press device, the slab vertical and horizontal roughing using an edger and a rough rolling mill. A sheet width control device in a hot rough rolling process for rolling,
Measuring means for measuring the width of the tip of the slab on the exit side of the pressing device;
Control means for controlling the opening degree of the edger in the first pass of the rough rolling so as to be equal to the measured width of the tip of the slab ,
The control means controls the opening degree of the edger in the first pass of the rough rolling so as to be equal to the measured width of the front end portion of the slab so that the edger follows the end face of the steady portion of the slab. A plate width control device for controlling an opening degree of an edger .

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