Method for judging the propriety of continued edging of slab, method for manufacturing steel plate, device for judging the propriety of continued edging of slab, and device for manufacturing steel plate

Abstract

To provide a method for judging the propriety of the continuation of the edging of a slab.SOLUTION: The method for judging the propriety of the continuation of the edging of the slab judges the propriety of the continuation of the edging of the slab. The method includes a reference data acquisition step of acquiring reference data that serves as a reference for a degree of twist of the slab, a position information acquisition step of acquiring position information of the slab at a plurality of points parallel to an upper side or a lower side formed along a width direction of the slab, a prediction information generation step of generating prediction information that predicts a degree of twist of the slab when the edging is continued, based on the reference data and the position information of the plurality of points, and a suitability information generation step of generating suitability information regarding suitability of continuation of the edging of the slab, based on the prediction information. The position information is position information measured during the edging of the slab.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for determining whether or not to continue width reduction of a slab, a steel plate manufacturing method, a slab width reduction continuation suitability determination device, and a steel plate manufacturing device. [Background technology]

[0002] For example, a hot rolling line for producing hot-rolled steel sheets includes a heating furnace, a roughing mill, and a finishing mill. The hot rolling line also includes a width reducing section between the heating furnace and the roughing mill, which reduces the width of the slab. That is, the slab is adjusted to a plate width according to the product specifications by the width reducing section, and then rolled to a predetermined thickness.

[0003] If rolling is performed with a twisted slab, defects in quality such as scratches may occur. Therefore, it is common to detect twists in the slab before rolling. For example, in Patent Document 1, the dimensions of two specific slabs are obtained from an image of the side surface of the slab after width reduction, and it is determined whether the width reduction is normal or not based on the absolute value of the difference between these two dimensions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4457888 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when width reduction is performed while the slab is twisted, a vertical load is also applied to the dies of the width reduction device due to the reaction force of the slab. If the vertical load exceeds the load capacity of the width reduction device, there is a risk of the width reduction device being damaged.

[0006] The present invention has been made in consideration of the above problems, and aims to provide a method for determining whether or not to continue width reduction of a slab, which is capable of determining whether or not to continue width reduction of a slab. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following features.

[0008] [1] A method for determining whether slab width reduction should continue, which determines whether slab width reduction should continue, a reference data acquisition step of acquiring reference data that serves as a reference for the degree of twist of the slab; a position information acquisition step of acquiring position information of the slab at a plurality of points parallel to an upper edge or a lower edge formed along the width direction of the slab; a prediction information generating step of generating prediction information that predicts the degree of twist of the slab when the width reduction is continued based on the reference data and the position information of a plurality of points; and a suitability information generating step of generating suitability information regarding the suitability of continuing width reduction of the slab based on the prediction information, A method for determining whether or not to continue width reduction of a slab, wherein the position information is position information measured during width reduction of the slab. [2] a torsion amount calculation step of calculating a torsion amount of the slab based on the position information of a plurality of points; A shape information acquisition step of acquiring shape information of the slab including the length of the slab in the width direction, The method for determining whether or not to continue width reduction of a slab described in [1] is such that, in the prediction information generation process, the prediction information is generated based on the calculated amount of twist of the slab, the shape information of the slab, and the reference data. [3] A method for determining whether or not to continue width reduction of a slab described in [1] or [2], in which the position information acquisition process acquires the position information of multiple points measured from the time the slab is pressed from above and below to the end of the contact length of the width reduction. [4] A method for manufacturing a steel plate, comprising the steps of: manufacturing a steel plate using the method for determining whether a slab is suitable for continuing width reduction according to any one of [1] to [3]; a width reduction step of performing the width reduction on the slab from which the slab to be subjected to the width reduction has been selected in a manner according to the suitability information; a rolling step of rolling the slab that has been subjected to the width reduction. [5] A slab width reduction continuation suitability determination device for determining whether or not slab width reduction is suitable for continuation, a reference data acquisition unit that acquires reference data that serves as a reference for the degree of twist of the slab; a position information acquisition unit that acquires position information of the slab at multiple points parallel to an upper edge or a lower edge formed along the width direction of the slab; a prediction information generating unit that generates prediction information that predicts the degree of twist of the slab when the width reduction is continued based on the reference data and the position information of a plurality of points; and a suitability information generating unit that generates suitability information regarding the suitability of continuing width reduction of the slab based on the prediction information. The position information acquisition unit acquires position information measured during width reduction of the slab, and is a device for determining whether or not to continue width reduction of the slab. [6] A steel plate manufacturing apparatus for manufacturing steel plates, [5] The slab width reduction continuation suitability determination device according to the present invention; a width reducing section that performs width reduction on the slab from which the slab to be subjected to width reduction has been selected in a manner according to the suitability information; a rolling section that rolls the slab that has been subjected to the width reduction. [Effects of the Invention]

[0009] The method for determining whether to continue width reduction of a slab of the present invention includes a prediction information generation step of generating prediction information that predicts the degree of twist of the slab when it is width reduced, based on reference data that serves as a reference for the degree of twist of the slab and position information of multiple points on the slab.The method for determining whether to continue width reduction of a slab also includes a suitability information generation step of generating suitability information regarding the suitability of continuing width reduction of the slab based on the generated prediction information.Therefore, while the slab is being width reduced, it is possible to predict whether it is appropriate to continue width reduction of the slab.This makes it possible to improve the production efficiency of steel sheets. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing an overview of a steel plate manufacturing apparatus. [Figure 2] FIG. 2 is an explanatory diagram showing a state in which a slab is width-reduced. [Figure 3] FIG. 2 is an explanatory diagram showing a state in which a slab is width-reduced in a width-reducing section. [Figure 4] FIG. 2 is an explanatory diagram showing how the shape of a slab is measured by a measuring unit. [Figure 5] FIG. 2 is a functional block diagram of a device for predicting the suitability of rolling a slab. [Figure 6] 1 is a flow chart of a steel plate manufacturing method, including a processing flow of a method for determining whether or not slab width reduction should continue. [Figure 7] FIG. 7 is an explanatory diagram showing an aspect of the position information acquisition step in step S02 of FIG. 6. [Figure 8] FIG. 7 is an explanatory diagram showing an aspect of the prediction information generating step in step S05 of FIG. 6. [Figure 9] FIG. 10 is an explanatory diagram showing the relationship between the reference data and the position information of multiple points of a slab. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a steel plate manufacturing apparatus 100 that manufactures steel plates by rolling slabs. In the steel plate manufacturing apparatus 100 of Fig. 1, a slab SB is transported in a transport direction D1 to manufacture steel plates. The steel plate manufacturing apparatus 100 has a heating furnace 10. In the heating furnace 10, the slab SB is heated to a predetermined temperature.

[0012] The steel plate manufacturing apparatus 100 has a width reducing section 20 and a measurement section 30. In the width reducing section 20, the slab SB is reduced in the width direction until it reaches a predetermined width. In addition, the shape of the slab SB while being reduced in width by the width reducing section 20 is measured by the measurement section 30.

[0013] The measurement unit 30 is not particularly limited, but may be, for example, a distance measuring device capable of measuring the shape of the slab SB. In this embodiment, an example will be described in which a distance measuring device such as LiDAR (Light Detection And Ranging) is used as the measurement unit 30.

[0014] The steel plate manufacturing apparatus 100 has a roughing rolling section 40 and a finishing rolling section 50. The roughing rolling section 40 and the finishing rolling section 50 have a pair of work rolls arranged to sandwich the slab SB from above and below. Each of the pair of work rolls is supported by a backup roll. In the steel plate manufacturing apparatus 100, the roughing rolling section 40 and the finishing rolling section 50 constitute a rolling section that rolls the slab SB that has been subjected to width reduction.

[0015] In the rough rolling section 40, the width-reduced slab SB is subjected to rough rolling until it reaches a predetermined thickness. In addition, in the finish rolling section 50, the rough-rolled slab SB is subjected to finish rolling until it reaches a predetermined thickness. The finish-rolled slab SB becomes a steel plate.

[0016] The steel plate manufacturing apparatus 100 has a run-out table 60 that cools the finish-rolled steel plate, and a coiler 70 that winds up the cooled steel plate. On the run-out table 60, the steel plate is cooled to a predetermined temperature by being sprayed with cooling water.

[0017] The steel plate manufacturing apparatus 100 has a slab width reduction continuation suitability determination device 80 that determines whether it is appropriate to continue width reduction of the slab SB by the width reduction section 20. The slab width reduction continuation suitability determination device 80 is connected to the width reduction section 20 and the measurement section 30 so as to be able to communicate data.

[0018] 2 shows a state in which the slab SB is width-reduced. As shown in FIG. 2, the width-reducing section 20 is provided with a conveying section 15 that conveys the slab SB in the conveying direction D1.

[0019] The width reducing section 20 has pinch rolls 21 and 22 arranged in the conveying direction D1. The pinch rolls 21 and 22 are arranged so that the slab SB can be sandwiched between a pair of rolls arranged in the vertical direction.

[0020] A pair of dies 23 for pressing down the slab SB in the width direction are provided between the pinch rolls 21 and 22. The pair of dies 23 are arranged opposite to each other in the left-right direction when viewed from the conveying direction D1.

[0021] The measuring unit 30 measures the shape of the slab SB while the slab SB is being pressed down in width. In this embodiment, the measuring unit 30 is provided so as to face the upper surface of the slab SB.

[0022] 3 shows how the slab SB is width-reduced in the width-reducing section 20. The pair of dies 23 are formed with an inclined surface 23a that gradually narrows in width in the opposing direction, and a flat surface 23b that extends in the conveying direction D1 continuous from the inclined surface.

[0023] The inclined surface 23a and the flat surface 23b form an angle α. The die 23 has a feed amount dL set to a predetermined length. The slab SB has a bending point formed by width reduction, i.e., a position P0 which is the end of the contact length CL.

[0024] In the width direction DX of the slab SB, one end side may be at a different height position from the other end side, i.e., twisting may occur. Here, for example, if the pressing force of the pinch rolls 21 is set to about 50 tf, the weight of the slab SB is about 15-20 tf. In this case, when the slab SB is sandwiched between the pinch rolls 21, the amount of twist in the portion pressed by the pinch rolls 21 becomes zero. In other words, in the width direction DX of the slab SB, the height positions from one end side to the other end side are the same.

[0025] It is preferable that the measurement unit 30 images the slab SB while the slab SB is sandwiched between the pinch rolls 21. By having the measurement unit 30 image the slab SB in this state, it is possible to image the shape of the slab SB in a state where the variations in height in the width direction DX have been leveled.

[0026] That is, the slab SB may be measured by the measuring unit 30 while being pressed from above and below. Note that the slab SB may be pressed by a pressing means other than the pinch roll 21, as long as the slab SB is pressed from above and below and the variations in height in the width direction can be evened out.

[0027] The measuring unit 30 measures the shape of the slab SB at any location from when the slab SB is pressed by the pinch rolls 21 to a position P0 that is the end of the contact length CL.

[0028] Fig. 4 shows an aspect in which the shape of the slab SB is measured by the measuring unit 30. As shown in Fig. 4, for example, a pair of measuring units 30 are provided along the width direction DX of the slab SB.

[0029] Each of the measurement units 30 is provided, for example, on the ceiling or the like, at the same height. Each of the measurement units 30 is arranged with its optical axis facing the upper surface of the slab. In the example shown in FIG. 4, one of the measurement units 30 is arranged opposite the upper surface of one end of the slab SB in the width direction DX. The other measurement unit 30 is arranged opposite the upper surface of the other end of the slab SB in the width direction DX. Note that each of the measurement units 30 may be arranged with its optical axis facing the lower surface of the slab.

[0030] One measurement unit 30 measures the distance Ds1 from that measurement unit 30 to the top surface of one end of the slab SB in the width direction DX. The other measurement unit 30 measures the distance Ds2 from that measurement unit 30 to the top surface of the other end of the slab SB in the width direction DX. In the example shown in Figure 4, the distance Ds1 is the vertical distance from one measurement unit 30 to the top surface of one end of the slab SB in the width direction DX. The distance Ds2 is the vertical distance from the other measurement unit 30 to the top surface of the other end of the slab SB in the width direction DX. Note that the measurement unit 30 only needs to be able to measure the distance Ds1 and the distance Ds2, and may be configured as a single measurement unit 30.

[0031] Figure 5 shows the functional blocks of the device 80 for determining whether or not to continue width reduction of a slab. As shown in Figure 5, the device 80 for determining whether or not to continue width reduction of a slab has an input / output unit 81 that is connected to external devices, a memory unit 82 that stores various data, and a control unit 83 that controls the operation of the device 80 for determining whether or not to continue width reduction of a slab. The input / output unit 81, the memory unit 82, and the control unit 83 are connected to each other via a bus 84 so that they can communicate data with each other.

[0032] The input / output unit 81 is an interface that is provided to enable data communication with an external device. In this embodiment, the input / output unit 81 is connected to the measurement unit 30.

[0033] The memory unit 82 is a writable non-volatile memory such as an EPROM. The memory unit 82 is not particularly limited, but may be, for example, a storage device such as an HDD or SSD. The memory unit 82 stores measurement data such as distance Ds1 and distance Ds2 measured by the measurement unit 30, as well as reference data that serves as a standard for the degree of twist of the slab. The reference data is not particularly limited, but may be, for example, the twist angle, which is the angle between the horizontal and a line connecting multiple points on the slab that are parallel to the upper or lower edge formed along the width direction of the slab. Below, an example in which the twist angle is used as the reference data will be described.

[0034] The control unit 83 is a computer including a CPU. The control unit 83 controls the operation of the slab width reduction continuation suitability determination device 80. The control unit 83 has a reference data acquisition unit 83a that acquires reference data that serves as a reference for the degree of twist of the slab, and a position information acquisition unit 83b that acquires position information of multiple points on the slab. The control unit 83 also has a twist amount calculation unit 83c that calculates the amount of twist of the slab SB, and a shape information acquisition unit 83d that acquires shape information of the slab SB.

[0035] The control unit 83 has a prediction information generation unit 83e that generates prediction information that predicts the degree of twisting of the slab when width reduction is continued, and a suitability information generation unit 83f that generates suitability information regarding the suitability of continuing width reduction of the slab.

[0036] The functions of the reference data acquisition unit 83a, the position information acquisition unit 83b, the twist amount calculation unit 83c, the shape information acquisition unit 83d, the prediction information generation unit 83e, and the suitability information generation unit 83f are realized by executing programs stored in the memory unit 82.

[0037] The reference data acquisition unit 83a reads out the reference data stored in the storage unit 82 to acquire the reference data.

[0038] The position information acquisition unit 83b reads out the measurement data measured by the measurement unit 30 from the storage unit 82, and acquires position information of multiple points parallel to the upper or lower side formed along the width direction of the slab.

[0039] The prediction information generating unit 83e generates prediction information that predicts the degree of twisting of the slab when width reduction is continued, based on the reference data and position information of a plurality of points.

[0040] The suitability information generating unit 83f generates suitability information regarding the suitability of continuing the width reduction of the slab based on the prediction information.

[0041] 6 shows a flow of a steel plate manufacturing method including a process flow of a method for determining whether or not to continue width reduction of a slab. The process flow of the method for determining whether or not to continue width reduction of a slab is executed, for example, during width reduction of the slab SB.

[0042] As shown in FIG. 6, the reference data acquisition unit 83a executes the reference data acquisition step by reading out the reference data stored in the storage unit 82 (step S01).

[0043] The position information acquisition unit 83b reads out the measurement data measured by the measurement unit 30 from the memory unit 82 and executes the position information acquisition process (step S02). In the position information acquisition process of step S02, position information of multiple points parallel to the upper or lower edge formed along the width direction DX of the slab is acquired. The position information acquired in the position information acquisition process of step S02 is information measured during the width reduction of the slab SB, i.e., distance Ds1 and distance Ds2.

[0044] The twist amount calculation unit 83c executes a twist amount calculation step of calculating the twist amount of the slab using the position information of the multiple points of the slab SB acquired in the position information acquisition step of step S02 (step S03).

[0045] The morphological information acquisition unit 83d executes a morphological information acquisition step of acquiring morphological information of the slab SB (step S04). The morphological information acquisition unit 83d acquires the morphological information of the slab SB, including the width direction length of the slab SB, for example, by acquiring the dimensional values ​​of the slab stored in the memory unit 82.

[0046] The prediction information generating unit 83e generates prediction information using the amount of twist of the slab SB, the shape information of the slab SB, and the reference data, and executes the prediction information generating step (step S05).

[0047] The suitability information generating unit 83f generates suitability information regarding the suitability of continuing the width reduction of the slab based on the prediction information generated in the prediction information generating step of step S03 (step S06).

[0048] The control unit 83 determines whether or not it is appropriate to continue the width reduction of the slab SB, also based on the suitability information generated in the suitability information generating step of step S06 (step S07).

[0049] When the control unit 83 determines in step S07 that it is appropriate to continue width reduction for the slab (step S07: YES), it continues the width reduction process (step S08). Thus, in the width reduction continuation process of step S08, width reduction is continued for the slab that has been selected as the target for continuing width reduction based on the suitability information.

[0050] Next, the rolling process is carried out by rolling the width-reduced slab in the roughing mill 40 and the finishing mill 50 (step S09). The slab SB is rolled in the rolling process of step S09 to be produced as a steel plate.

[0051] If the slab width reduction continuation suitability determination device 80 determines in step S07 that it is not appropriate to continue width reduction (step S07: NO), it executes a removal process to remove the slab from the production line of the steel plate manufacturing equipment 100 (step S10).

[0052] Furthermore, the processing and judgment in steps S01 to S07 should be performed when the width reduction amount in the width reduction portion 20 is 300 mm or more. This is because problems caused by the amount of twist tend to occur when width reduction is performed with a width reduction amount of 300 mm or more. By doing so, it is possible to effectively improve the yield.

[0053] Figure 7 shows the position information acquisition process of step S02 in Figure 6. Figure 7 shows the width direction DX of the slab SB, the longitudinal direction DY of the slab SB, and the thickness direction DZ of the slab SB. The longitudinal direction DY of the slab SB coincides with the conveying direction D1 of the slab SB.

[0054] Point P1 on one end side in the width direction DX and point P2 on the other end side in the width direction DX are located on the end surface of the slab SB in the longitudinal direction DY. Points P1 and P2 are points parallel to the upper side UL or lower side BL of the slab SB. In the example shown in Figure 7, points P1 and P2 are end points of the upper surface.

[0055] In the position information acquisition step of step S02, position information of a plurality of points parallel to the upper side UL or the lower side BL of the slab SB is acquired. In the example shown in Fig. 7, point P1 is located at a higher position than point P2.

[0056] The difference in height between point P1 and point P2 is expressed as the amount of twist Δh, which is calculated from the absolute value of the difference between the distance Ds1 and the distance Ds2 measured by the measuring unit 30.

[0057] Figure 8 shows how prediction information is generated in the prediction information generation process of step S05 in Figure 6. The solid line in Figure 8 represents the end face on the base end side in the conveying direction D1 of slab SB1 before width reduction. The dashed line represents the end face on the base end side in the conveying direction D1 of slab SB2 after width reduction.

[0058] When slab SB1 is width-reduced, a frictional force of several hundred tons acts on slab SB2. Therefore, even if slab SB1 is twisted, the thickness center positions P1b and P2b can be considered to move from the center positions P1a and P2a while maintaining their positions in the width direction DX. In other words, the thickness center positions P1b and P2b after width reduction can be considered to be the same positions in the thickness direction DZ as the thickness center positions P1a and P2a before width reduction.

[0059] Here, the angle between the line connecting the central positions P1a (P1b) and P2a (P2b) and the horizontal direction is defined as the twist angle. The twist amount Δh, which is the difference between the central positions P1a (P1b) and P2a (P2b), is equal to the product of the twist angles tanφ1 and tanφ2 before and after width reduction and the widths w1 and w2 of the slab. In other words, these can be expressed mathematically as the following equation (1).

[0060] (Width after width reduction w2) × (Twist angle after width reduction tanφ2) = (Width before width reduction w1) × (Twist angle before width reduction tanφ1) = (Twist amount Δh) (1)

[0061] When the twist angle tanφ2 after width reduction is summarized in this formula (1), it is expressed by the following formula (2).

[0062] (Twist angle tanφ2 after width reduction) = (slab width w1 before width reduction) / (slab width w2 after width reduction) × (twist angle tanφ1 before width reduction) = (twist amount Δh) / (slab width w2 after width reduction) (2)

[0063] The width w2 of the slab after width reduction can be determined using the values ​​of the operating conditions. As the values ​​of the operating conditions, for example, the set values ​​of the process computer can be used. The twist amount Δh before width reduction can be measured as described above. That is, the twist angle tanφ2 after width reduction can be calculated using equation (2) if the twist amount Δh and the width w2 of the slab after width reduction can be obtained. The prediction information generating unit 83e generates, for example, the twist angle tanφ2 after width reduction as prediction information.

[0064] For example, when the helix angle tanφ2 after width reduction generated by the prediction information generating unit 83e is equal to or less than the value of reference data, the suitability information generating unit 83f generates suitability information indicating that the slab is suitable for continued width reduction. Also, when the helix angle tanφ2 after width reduction exceeds the value of reference data, the suitability information generating unit 83f generates suitability information indicating that the slab is not suitable for continued width reduction. Note that the value of the helix angle tanφ2 after width reduction used in the reference data can be the minimum angle or average value of the twist angles of slabs previously removed from the hot rolling line.

[0065] As described above, the method for determining whether to continue width reduction of a slab of the present invention includes a prediction information generating step of generating prediction information predicting the degree of twist of the slab when the slab is width reduced, based on reference data serving as a reference for the degree of twist of the slab and position information of multiple points on the slab. The method for determining whether to continue width reduction of a slab also includes a suitability information generating step of generating suitability information regarding the suitability of continuing width reduction of the slab based on the generated prediction information. Therefore, while the slab is being width reduced, it is possible to predict whether or not to continue width reduction of the slab. As shown in the above-described embodiment, if it is determined in step S07 that continuing width reduction is inappropriate (step S07: NO), the removal step of step S10 is executed. In other words, if it is determined that the amount of twist exceeds the threshold, the width reduction process is interrupted and the slab is not reduced. This allows slabs suitable for continued width reduction to be selected and width reduction is performed, thereby improving steel plate production efficiency.

[0066] In the above embodiment, points P1 and P2 are defined as midpoints in the thickness direction DZ. However, points P1 and P2 are not limited to this, and can be set at any position as long as they are parallel to the upper or lower side. Furthermore, the number of points is not limited to two, points P1 and P2, and similar processing can be performed on multiple points.

[0067] (Variation) In the above embodiment, an example has been described in which suitability information is generated based on the twist angle tanφ2 of the slab after width reduction and the value of the reference data. However, the generation of suitability information is not limited to this manner, and may be performed, for example, based on the positional relationship of points P1 and P2 with respect to the reference data.

[0068] Figure 9 shows the relationship between the positional information of multiple points on the slab and the reference data, i.e., the positional relationship of points P1 and P2 with respect to the reference data. The reference data shown in Figure 9 is a reference line L1 that serves as a reference for the degree of twist of the slab. The reference line L1 is a line that corresponds to the twist angle tanφ3 of the slab SB.

[0069] The suitability information generating unit 83f, for example, aligns the reference line L1 so that it is located on point P1, and generates suitability information according to the position of point P2. For example, if point P2 is located above the reference line L1, the twist angle connecting points P1 and P2 will be gentler than that of the reference line L1. In this case, since the amount of twist of the slab SB after width reduction is expected to be below the standard, the suitability information generating unit 83f generates suitability information indicating that the slab is suitable for continued width reduction.

[0070] Furthermore, for example, when point P2 is located below the reference line L1, the twist angle is larger than that of the reference line L1. In this case, since it is assumed that the amount of twist during width reduction exceeds the standard, the suitability information generating unit 83f generates suitability information indicating that the slab is not suitable for continued width reduction.

[0071] Even if the suitability information is generated in this manner, it becomes possible to predict whether or not to continue width reduction of a slab while the width reduction of the slab is being performed, thereby improving the production efficiency of steel sheets. [Example]

[0072] A steel plate was manufactured using the steel plate manufacturing apparatus 100 described in the above embodiment. Two laser range finders were used as the measurement unit 30.

[0073] The slabs used were Al-killed low-carbon steel slabs measuring 7000 to 8000 mm in length, 260 mm in thickness, and 1200 to 1800 mm in width. The widths are the dimensions before width reduction. The slab heating temperature was 1100 to 1200°C. The slab width reduction was 250 to 350 mm. The slab feed rate at the bottom of the width reduction section was 400 mm. The number of slabs was 1000. The slab width after width reduction (W2) was calculated from the slab width before width reduction (W1) and the width reduction amount (ΔW) set in the process computer. Width reduction was performed on 1000 slabs, and the number of slabs removed from the production line was counted. The results are shown in Table 1.

[0074] As a comparative example, a steel plate was produced by a conventional method without checking whether the slab was twisted during width reduction. The results are shown in Table 1.

[0075] As shown in Table 1, in the inventive example, the amount of twist of 10 slabs was determined to exceed the threshold value (reference data). The width reduction of these slabs was stopped and they were transported outside the production line. As a result, no failures occurred at the width reduction lower part in the inventive example. In contrast, in the comparative example, failures at the width reduction lower part occurred three times due to the expansion of the twist in the slab.

[0076] [Table 1]

[0077] When a failure occurs in the width reduction lower section, the line is stopped until the repair is completed. Therefore, it is desirable to reduce the number of failures in the width reduction lower section. In the example of the present invention, since the amount of twist of the slab during width reduction can be predicted, it was possible to reduce the number of failures in the width reduction lower section compared to the comparative example. Therefore, the hot rolling line was able to operate stably. [Explanation of symbols]

[0078] 100 Steel plate manufacturing equipment 10 Furnace 20 Lower part of width pressure 30 Measurement section 40 Rough rolling section 50 Finishing Rolling Section 60 Runout Table 83a Reference data acquisition section 83b Location information acquisition unit 83e Prediction information generation unit 83f Suitability information generation unit

Claims

1. A method for determining whether slab width reduction should continue, which determines whether slab width reduction should continue, a reference data acquisition step of acquiring reference data that serves as a reference for the degree of twist of the slab; a position information acquisition step of acquiring position information of the slab at a plurality of points parallel to an upper edge or a lower edge formed along the width direction of the slab; a prediction information generating step of generating prediction information that predicts the degree of twist of the slab when the width reduction is continued based on the reference data and the position information of a plurality of points; and a suitability information generating step of generating suitability information regarding the suitability of continuing width reduction of the slab based on the prediction information, A method for determining whether or not to continue width reduction of a slab, wherein the position information is position information measured during width reduction of the slab.

2. a torsion amount calculation step of calculating a torsion amount of the slab based on the position information of a plurality of points; A shape information acquisition step of acquiring shape information of the slab including the length of the slab in the width direction, A method for determining whether or not to continue width reduction of a slab as described in claim 1, wherein in the prediction information generation process, the prediction information is generated based on the calculated amount of twist of the slab, the shape information of the slab, and the reference data.

3. A method for determining whether or not to continue width reduction of a slab as described in claim 1 or 2, wherein in the position information acquisition process, the position information of multiple points measured from the time the slab is pressed from the top and bottom directions to the end of the contact length of the width reduction is acquired.

4. A steel plate manufacturing method in which a steel plate is manufactured using the method for determining whether a slab width reduction continuation is suitable according to claim 1 or 2, a width reduction step of performing the width reduction on the slab from which the slab to be subjected to the width reduction has been selected in a manner according to the suitability information; a rolling step of rolling the slab that has been subjected to the width reduction.

5. A steel plate manufacturing method in which a steel plate is manufactured using the method for determining whether a slab width reduction continuation is appropriate according to claim 3, a width reduction step of performing the width reduction on the slab from which the slab to be subjected to the width reduction has been selected in a manner according to the suitability information; a rolling step of rolling the slab that has been subjected to the width reduction.

6. A slab width reduction continuation suitability determination device for determining whether or not slab width reduction is suitable for continuation, a reference data acquisition unit that acquires reference data that serves as a reference for the degree of twist of the slab; a position information acquisition unit that acquires position information of the slab at multiple points parallel to an upper edge or a lower edge formed along the width direction of the slab; a prediction information generating unit that generates prediction information that predicts the degree of twist of the slab when the width reduction is continued based on the reference data and the position information of a plurality of points; and a suitability information generating unit that generates suitability information regarding the suitability of continuing width reduction of the slab based on the prediction information. The position information acquisition unit acquires position information measured during width reduction of the slab, and is a device for determining whether or not to continue width reduction of the slab.

7. A steel plate manufacturing apparatus for manufacturing steel plates, The device for determining whether or not a slab is suitable for continuing width reduction according to claim 6; a width reducing section that performs width reduction on the slab from which the slab to be subjected to width reduction has been selected in a manner according to the suitability information; a rolling section that rolls the slab that has been subjected to the width reduction.

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