Method and apparatus for inspecting the shape of cast slabs

Abstract

The present invention provides a method and apparatus for inspecting the shape of a cast slab that can accurately inspect the shape of a cast slab being transported on a conveyor line. [Solution] The slab shape inspection method includes the steps of: acquiring cold reference position coordinate data, which is position coordinate data of multiple points on two linear materials stretched parallel to the conveying direction of the slab, by light section method while the line is stopped, and setting a reference coordinate system using the acquired cold reference position coordinate data; and acquiring hot reference position coordinate data, which is position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is position coordinate data indicating the shape of the slab, by light section method while the line is in operation, converting the acquired hot measurement shape data into corrected data, which is position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data, and calculating a feature quantity that indicates the shape characteristics of the slab using the converted corrected data.

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting the shape of a cast slab and an apparatus for inspecting the shape of a cast slab. [Background technology]

[0002] Typical examples of square-shaped cast slabs produced by continuous casting include billets and slabs. However, billets are used in processes such as rolling, forging, extrusion, and drawing to produce steel bars and structural steel.

[0003] Patent Document 1 discloses an apparatus that irradiates a steel bar (product) being transported, which is the object to be measured, with a light cutting line, and then uses an imaging device to image the steel bar irradiated with the light cutting line and measure the three-dimensional shape of the surface of the steel bar. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5956411 [Overview of the project] [Problems that the invention aims to solve]

[0005] When high-temperature cast slabs are being transported along a conveyor line, the area around the conveyor line becomes hot due to the slabs. This causes thermal deformation of the support members for cameras installed near the conveyor line, and vibrations associated with transport can cause disturbances such as camera displacement. As a result, there is a problem in that the shape of the cast slabs cannot be inspected accurately using the light sectioning method.

[0006] This invention has been made in view of the above circumstances, and aims to provide a slab shape inspection method and a slab shape inspection apparatus that can accurately inspect the shape of a slab being transported on a conveyor line. [Means for solving the problem]

[0007] The present invention includes several means for solving the above problems, but to give one example, the slab shape inspection method is a slab shape inspection method for inspecting the shape of a slab with a square cross-section manufactured by continuous casting on a conveying line in which the slab is being conveyed along the longitudinal direction of the slab while it is at a high temperature, and the method includes a reference coordinate system setting step in which, in a line stopped state in which the slab is not on the conveying line, cold reference position coordinate data, which is the position coordinate data of multiple points on two linear materials stretched parallel to the conveying direction of the slab, is acquired by light sectioning, and a reference coordinate system setting step in which a reference coordinate system is set using the acquired cold reference position coordinate data, and the high temperature casting The process includes a line operation step in which a piece is being transported on the conveying line, acquiring hot reference position coordinate data, which is position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is position coordinate data indicating the shape of the cast slab, by light section method, converting the acquired hot measurement shape data into corrected data, which is position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration, and calculating a feature quantity that indicates the shape characteristics of the cast slab using the converted corrected data. [Effects of the Invention]

[0008] According to the present invention, the shape of a cast slab being transported on a conveyor line can be inspected with high precision. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the configuration of a cast slab shape inspection device according to one embodiment. [Figure 2] This figure shows an example of cold reference position coordinate data. [Figure 3] This figure shows an example of hot reference position coordinate data. [Figure 4] This figure shows an example of a correction transformation matrix. [Figure 5] This figure shows an example of shape data measured at a hot temperature. [Figure 6]This figure shows an example of a corrected approximation curve C′(n,m) for the reference coordinate system. [Figure 7] This figure shows an example of a projected approximation curve and an approximation line. [Figure 8] This figure shows examples of feature quantities that indicate the shape characteristics of a cast slab. [Figure 9] This figure shows an example of the degree of torsion. [Figure 10] This figure shows an example of warping. [Figure 11] This figure shows an example of a curve. [Figure 12] This figure shows an example of the processing procedure for inspecting the shape of a cast slab using a cast slab shape inspection device. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a diagram showing an example of the configuration of a slab shape inspection device according to this embodiment. The slab shape inspection device of this embodiment includes a transport line for transporting slabs (not shown for convenience), two linear materials, strings 100 and 200, a first camera 10, a second camera 20, a laser device 30, and a control device 50. In this embodiment, the slab is a billet, so the slab may also be referred to as a billet.

[0011] A slab is a semi-finished steel product made for metalworking processes such as rolling, forging, extrusion, and drawing. It can be manufactured using continuous casting equipment, which involves cooling and solidifying molten steel in a cylindrical mold, and then gradually drawing out the solidified portion to create a long, continuous steel material. The slab is transported along a conveyor line in the longitudinal direction. A billet is a slab with a length of, for example, 6 to 12 meters and a rectangular cross-section.

[0012] The strings 100 and 200 are stretched (positioned) parallel to the direction in which the cast slab is being transported.

[0013] The laser device 30 comprises three line laser devices: a first line laser device, a second line laser device, and a third line laser device. The first line laser device, the second line laser device, and the third line laser device are positioned at equal intervals along the transport direction of the transport line, and the lasers are applied to two sides (S) of the cast slab. m )[m=1, 2] and two strings 100, 200 are subjected to the laser beam R n They are positioned to irradiate [n=1, 2, 3].

[0014] The first camera 10 is positioned over two strings 100 and 200, and over the surface of the cast slab (two sides (S m The first line laser device, the second line laser device, and the third line laser device are positioned such that the irradiation area illuminated by the laser light from the first line laser device, the second line laser device, and the third line laser device is within the imaging range. The first camera 10 can measure the position and shape of the two strings 100 and 200, and the surface of the cast slab by the light section method. The light section method calculates the distance from the first camera 10 to the cast slab using triangulation by determining the triangle formed by connecting the first line laser device, the second line laser device, and the third line laser device, the first camera 10, the strings 100 and 200, and the cast slab, and measures the three-dimensional shape of the cast slab.

[0015] The second camera 20 performs periodic imaging (e.g., 30 fps) and detects surface scratches and patterns from images of the slab surface captured under conditions that ensure clear contrast. It then calculates the transport distance by comparing these images with the most recently captured image through pattern matching. The second camera 20 is positioned to acquire images of at least one side of the slab.

[0016] The control device 50 can be configured as a computer or the like. The control device 50 is equipped with a communication module and can communicate with the first camera 10, the second camera 20, and the laser device 30. The control device 50 controls the operation of the first camera 10, the second camera 20, and the laser device 30. The control device 50 can acquire measurement data measured by the light section method with the first camera 10 and image data captured with the second camera 20.

[0017] The measurement data obtained by the first camera 10 using the light section method includes cold reference position coordinate data, hot reference position coordinate data, and hot measurement shape data.

[0018] Figure 2 shows an example of cold reference position coordinate data. Cold reference position coordinate data is the position coordinate data of multiple points on two parallel strings 100 and 200 stretched along the conveying direction of the cast slab, when the line is stopped and the cast slab is not on the conveying line.

[0019] In this embodiment, as shown in Figure 2, the cold reference position coordinate data is obtained when the line is stopped, and laser beams R from the first line laser device, the second line laser device, and the third line laser device are perpendicular to the transport direction and parallel to each other, with respect to two water lines 100 and 200. n (n=1~3) were irradiated, and six points on two strings 100 and 200 were obtained by light sectioning (o n , p n This is the position coordinate data of ). On string 100, the position coordinate data of three points o1, o2, and o3 is obtained by laser lines 1, 2, and 3, and on string 200, the position coordinate data of three points p1, p2, and p3 is obtained by laser lines 1, 2, and 3.

[0020] The control device 50 can perform a reference coordinate system setting step to set a reference coordinate system using cold reference position coordinate data. The reference coordinate system (X, Y, Z) can be set as follows: Point o1 is the origin, the line passing through points o1 and o3 is the X-axis, the direction perpendicular to the X-axis on planes o1, o3, and p1 is the Y-axis, and the direction perpendicular to the X-axis and Y-axis is the Z-axis. The X-axis is the direction of transport of the cast slab.

[0021] The control device 50 sets, in a plane including two points (o1, o3) on one of the two water threads 100, 200 and one point (p1) on the other water thread 200, a straight line passing through the two points (o1, o3) on one of the water threads 100 as the X-axis by the reference coordinate system setting step, sets a Y-axis orthogonal to the X-axis, and sets a Z-axis orthogonal to the X-axis and the Y-axis. The reference coordinate system is an orthogonal coordinate system defined by the X-axis, the Y-axis, and the Z-axis.

[0022] FIG. 3 is a diagram showing an example of hot reference position coordinate data. The hot reference position coordinate data is position coordinate data of a plurality of points on the two water threads 100, 200 in the line operating state where a high-temperature slab is being conveyed on the conveying line.

[0023] More specifically, as shown in FIG. 3, the hot reference position coordinate data is, in the line operating state, for two adjacent side surfaces (S m ) [m = 1, 2] of the two water threads 100, 200 and the slab, laser light is irradiated from three first line laser devices, second line laser devices, and third line laser devices, and the position coordinate data of six points (o n ′, p n ′) irradiated with the laser light on the two water threads 100, 200. On the water thread 100, the position coordinate data of three points o1′, o2′, o3′ is obtained by the laser lines 1, 2, 3, and on the water thread 200, the position coordinate data of three points p1′, p2′, p3′ is obtained by the laser lines 1, 2, 3.

[0024] FIG. 4 is a diagram showing an example of a correction transformation matrix. The correction transformation matrix is created using the cold reference position coordinate data and the obtained hot reference position coordinate data so as to correct the measurement error due to the influence of disturbances including heat and vibration of the hot measurement shape data, and is for converting the hot measurement shape data into correction data which is position coordinate data on the reference coordinate system. The control device 50 can create a correction transformation matrix by the matrix creation step based on the cold reference position coordinate data and the hot reference position coordinate data.

[0025] More specifically, based on the cold reference position coordinate data obtained using the first line laser device, the second line laser device, and the third line laser device, the first cold vector, the second cold vector, and the third cold vector (o n ,p n Set [n=1, 2, 3]. Set the cold first vector, cold second vector, and cold third vector to (o1, p1), (o 2, This is represented as p2) and (o3,p3).

[0026] Furthermore, based on the hot reference position coordinate data obtained using the first line laser device, the second line laser device, and the third line laser device, the first hot vector, the second hot vector, and the third hot vector (o n ′,p n Set n=1, 2, 3. Set the first hot vector, second hot vector, and third hot vector to (o1', p1') and (o2') respectively. , This is represented as p2') and (o3',p3').

[0027] The control device 50 controls the cold first vector, the cold second vector and the cold third vector (o n ,p n ) are the first hot vector, the second hot vector, and the third hot vector (o n ',p n The first correction transformation matrix A1, the second correction transformation matrix A2, and the third correction transformation matrix A3, which convert to '), can be created as correction transformation matrices.

[0028] The control device 50 can convert hot measurement shape data into corrected data using a correction transformation matrix.

[0029] Figure 5 shows an example of hot measurement shape data. The hot measurement shape data is obtained from two sides (S) of the cast slab. m This is the position coordinate data (point cloud data) of the linear region irradiated by laser light on [m=1, 2].

[0030] The control device 50 controls two sides (S) of the cast slab obtained by the light section method. m) Point cloud data on (B (n,m) By converting ) using the least squares method, each laser beam R is obtained as hot measurement shape data. n The first hot data approximation curve (C) is a curve in a two-dimensional plane that includes the trajectory of the data. (n,1) ) and the second hot data approximation curve (C (n,2) ) is calculated. The first hot data approximation curve (C (n,1) ) and the second hot data approximation curve (C (n,2) A hot work data approximation curve (C) is, for example, an approximation curve expressed as a quadratic or sixth-degree polynomial. In the example in Figure 5, the first hot work data approximation curve C(n,1) is calculated from the point cloud data B(n,1) on the side surface S1 of the cast slab, and the first hot work data approximation curve C(n,2) is calculated from the point cloud data B(n,2) on the side surface S2 of the cast slab. Note that in Figure 5, the first hot work data approximation curve (C (n,1) ) and the second hot data approximation curve (C (n,2) The diagram is a schematic representation and may differ from the curve obtained through actual measurements.

[0031] Figure 6 shows an example of a corrected approximation curve C′(n,m) of the reference coordinate system. The control device 50 uses the first correction transformation matrix A1, the second correction transformation matrix A2, and the third correction transformation matrix A3 to calculate the first hot data approximation curve (C (n,1) ) and the second hot data approximation curve (C (n,2) By converting ) into a curve in the reference coordinate system, the first corrected approximation curve (C′) is used as correction data. (n,1) ) and the second corrected approximation curve (C′ (n,2) ) can be calculated. In the example in Figure 6, the first corrected approximation curve (C′) can be calculated on the side surface S1 of the cast slab. (n,1) ) is calculated, and the second corrected approximation curve (C′) is calculated on the side surface S2 of the cast slab. (n,2) ) has been calculated. Note that in Figure 6, the first corrected approximation curve (C' (n,1) ) and the second corrected approximation curve (C′ (n,2) The diagrams shown are schematic and may differ from actual curves.

[0032] Figure 7 shows an example of a projected approximation curve and an approximation line. The control device 50 controls the first corrected approximation curve (C' (n,1) ) and the second corrected approximation curve (C'(n,2) By projecting ) onto the YZ plane (X=0) of the reference coordinate system, the first projection approximation curve (D (n,1) ) and the second projection approximation curve (D (n,2) The control device 50 generates the first projection approximation curve (D (n,1) ) and the second projection approximation curve (D (n,2) By converting ) into an approximate line using the least squares method, the first approximate line (E (n,1) ) and the second approximation line (E (n,2) ) generates.

[0033] The control device 50 converts the hot measurement shape data into corrected data, which is position coordinate data on a reference coordinate system, using a correction transformation matrix created with the cold reference position coordinate data and the hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration. Using the converted corrected data, it can calculate feature quantities that represent the shape characteristics of the cast slab. Here, the corrected data is the first correction approximation curve (C' (n,1) ) and the second corrected approximation curve (C′ (n,2) ) includes.

[0034] Furthermore, as illustrated in Figure 7, the first corrected approximation curve (C' (n,1) ) and the second corrected approximation curve (C′ (n,2) Based on ), the first projection approximation curve (D (n,1) ), second projection approximation curve (D (n,2) ), the first approximation straight line (E (n,1) ) and the second approximation line (E (n,2) Since it can generate ), the correction data is the first projection approximation curve (D (n,1) ), second projection approximation curve (D (n,2) ), the first approximation straight line (E (n,1) ) and the second approximation line (E (n,2) It can be said that this includes ). Note that in Figure 7, the first projection approximation curve (D (n,1) ) and the second projection approximation curve (D (n,2) The diagrams shown are schematic and may differ from actual curves.

[0035] When a hot cast slab is being transported on a conveyor line, the presence of the hot slab on the conveyor line (near the camera) can cause the camera support to deform due to heat, or vibrations to occur during transport, leading to a shift in the camera's position. This makes it impossible to accurately measure the deviation from a fixed reference position. However, according to this embodiment, by setting a reference coordinate system and evaluating the correction data on that coordinate system, the effects of errors can be reduced, and the shape of the cast slab being transported on the conveyor line can be inspected with high accuracy.

[0036] Figure 8 shows an example of feature quantities that represent the shape characteristics of a cast slab. As shown in Figure 8, the feature quantities include at least one of the following: (1) straightness at position n, (2) bulge at position n, (3) indentation at position n, (4) rhomboidity at position n, (5) twist at position 2, (6) warp at position 2, and (7) bend at position 2. Position n is n=1, 2, 3, corresponding to laser lines 1, 2, 3.

[0037] The degree of linearity at position n is given by the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) The standard deviation of the distance and / or the second approximation line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is the standard deviation of the distance between the first approximation line (E). For example, the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) The standard deviation of the distance between the two ends of the range in which the data exists is the first projection approximation curve (D (n,1) ) from the first approximation line (E (n,1) The length of the perpendicular to ) is the first approximate line (E (n,1) It can be calculated by taking the positive square root of the average of the sum of the squares of the values ​​calculated at small intervals along the given line. The approximation curve used to calculate the linearity is preferably expressed by a high-order equation to improve the accuracy of the approximation, but if the order is too high the computational load increases, for example, an approximation curve expressed by a 6th-order equation is used. Linearity is a quantity that indicates how much the corresponding side of the rectangular cross-section of the cast slab deviates from a straight line, or in other words, a quantity that indicates the degree of unevenness on the side surface.

[0038] The amount of bulge at position n is given by the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) ) twice the maximum distance on the bulging side and / or the second approximation line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is twice the maximum distance on the bulging side. The approximation curve used to calculate the amount of bulging is preferably a quadratic equation. If the approximation curve is a quadratic equation, for example, the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) The maximum distance on the bulging side of ) is the first projection approximation curve (D) at the center of the range where data exists. (n,1) ) from the first approximation line (E (n,1) It can be easily calculated as the length of the perpendicular line to ).

[0039] The amount of indentation at position n is given by the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) ) twice the maximum distance on the indented side and / or the second approximation line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is twice the maximum distance on the indented side of the curve. The approximation curve used to calculate the amount of indentation is preferably a quadratic equation. If the approximation curve is a quadratic equation, for example, the first approximation line (E (n,1) The first projection approximation curve (D) for ) (n,1) The maximum distance on the indented side of ) is the first projection approximation curve (D) at the center of the range where data exists. (n,1) ) from the first approximation line (E (n,1) It can be easily calculated as the length of the perpendicular line to ).

[0040] The rhomboidity at position n is given by the first approximation line (E (n,1) ) and the second approximation line (E (n,2) This is the value obtained by subtracting 90° from the angle θ made by the two sides.

[0041] The degree of twist at position 2 is given by the first approximation line (E (n,1) ) and the second approximation line (E (n,2)Let the angle bisector of the angle formed by

[0042] Figure 9 is a diagram showing an example of the degree of twist. As shown in Figure 9, the angle bisector of the angle formed by the first approximate straight line (E (1,1) ) and the second approximate straight line (E (1,2) ) is defined as F(1), the angle bisector of the angle formed by the first approximate straight line (E (2,1) ) and the second approximate straight line (E (2,2) ) is defined as F(2), and the angle bisector of the angle formed by the first approximate straight line (E (3,1) ) and the second approximate straight line (E (3,2) ) is defined as F(3). If the relative angle between F(1) and F(2) is φ1 and the relative angle between F(2) and F(3) is φ2, the degree of twist can be calculated by the formula (φ1 + φ2) / 2.

[0043] The warp at position 2 is the distance between e (n,1) and e1, where e (n,1) is the midpoint of the line segment corresponding to the linear region in the first approximate straight line (E (1,1) ), and e1 is the intersection point of the straight line passing through e (3,1) and e (2,1) and the straight line parallel to the Y-axis passing through e (2,1) . [[ID=3^4]]

[0044] Figure 10 is a diagram showing an example of the warp. As shown in Figure 10, e (1,1) is the midpoint of the line segment corresponding to the linear region in the first approximate straight line (E (1,1) ), e (2,1) is the midpoint of the line segment corresponding to the linear region in the first approximate straight line (E (2,1) ), and e (3,1) is the midpoint of the line segment corresponding to the linear region in the first approximate straight line (E (3,1) ). Let e (1,1) and e (3,1) be the midpoints, and the straight line passing through them intersects the straight line parallel to the Y-axis passing through e (2,1) at the intersection point e1. The warp can be calculated as the distance between the midpoint e (2,1) and the intersection point e1.

[0045] The curvature at position 2 is given by the second approximate line (E (n,2) The midpoint of the line segment in the part of the linear region corresponding to the linear region is e (n,2) to, e (1,2) and e (3,2) A straight line passing through and e (2,2) When e2 is the intersection point of a line passing through and parallel to the Z-axis, then e (2,2) This is the distance between and e2.

[0046] Figure 11 shows an example of curvature. As shown in Figure 11, the second approximate line (E (1,2) The midpoint of the line segment in the part of the linear region corresponding to the linear region is e (1,2) Let the second approximation line (E (2,2) The midpoint of the line segment in the part of the linear region corresponding to the linear region is e (2,2) Let the second approximation line (E (3,2) The midpoint of the line segment in the part of the linear region corresponding to the linear region is e (3,2) Let's assume the midpoint is e. (1,2) and e (3,2) The line passing through the midpoint e (2,2) Let e2 be the intersection point where the line passing through the point intersects with a line parallel to the Z-axis. The curve is at the midpoint e (2,2) This can be calculated as the distance between and the intersection point e2.

[0047] Next, we will explain the method for inspecting the shape of a cast slab using a cast slab shape inspection device.

[0048] Figure 12 shows an example of the processing procedure for slab shape inspection using a slab shape inspection device. For convenience, the control device 50 will be used as the main component of the process below. First, before the billet is transported on the conveyor line, that is, when the line is stopped and the billet is not on the conveyor line, the control device 50 controls the operation of the first camera 10 and the laser device 30 to perform measurement (setting) of the reference coordinate system. The setting of the reference coordinate system is illustrated in Figure 2.

[0049] When the line is operating and the high-temperature billet is being transported on the conveyor line, in step S1, the control device 50 receives an external signal indicating that the leading edge of the billet (cast slab) being transported on the conveyor line has reached a predetermined position, and controls the operation of the second camera 20 to start taking pictures.

[0050] In step S2, the billet tip enters the measurement area when it reaches the first laser.

[0051] In step S3, when the billet tip reaches the second laser, the control device 50 controls the operation of the first camera 10 and the laser device 30 to perform the measurement. That is, the control device 50 acquires hot reference position coordinate data and hot measurement shape data. The hot reference position coordinate data is illustrated in Figure 3. The hot measurement shape data is illustrated in Figure 5. In step S3, the measurement result is acquired only for the first line (laser line).

[0052] In step S4, when the billet tip reaches the third laser, the control device 50 performs the measurement. That is, the control device 50 acquires hot reference position coordinate data and hot measurement shape data. Note that in step S4, measurement results are acquired only for the first and second lines.

[0053] In step S5, once the billet has been transported by the laser pitch, the control device 50 performs the measurement. Specifically, the control device 50 acquires hot reference position coordinate data and hot measurement shape data. In step S5, measurement results are acquired for all three lines (laser lines). The measurement is then repeated until the tail end of the billet passes the first laser.

[0054] The control device 50 calculates feature quantities each time a measurement is performed, that is, each time hot reference position coordinate data and hot measurement shape data are acquired (or each time the billet transport distance becomes equal to the interval between laser beams). The calculation of feature quantities is illustrated in Figures 6 to 8.

[0055] The control device 50 may calculate (1) the linearity at position n, (2) the amount of bulge at position n, (3) the amount of indentation at position n, and (4) the rhomboidity at position n as the load average of values ​​obtained by calculating multiple times.

[0056] The control device 50 may output an alarm if the absolute value of at least one of the following exceeds a predetermined threshold: (1) straightness at position n, (2) bulge at position n, (3) indentation at position n, (4) rhomboidity at position n, (5) twist at position 2, (6) warp at position 2, and (7) bend at position 2.

[0057] Traditionally, billet shape inspection was often performed manually outside the production line, such as in the billet yard, making 100% inspection difficult. This resulted in defective products being released, and the effort required for system input and the variability of measurement results hindered the process of feeding the results back into operations and digitizing the line. Furthermore, when inspectors entered the operating line to perform measurements, there was a risk of serious accidents such as falls and burns. In addition, with general light sectioning method measurements, the internal alignment of the camera system can be shifted due to disturbances such as heat and vibration during operation, leading to issues with the accuracy of the measurement.

[0058] However, according to this embodiment, cold reference position coordinate data is acquired by light section method when the line is stopped and no cast slab is on the conveying line, and a reference coordinate system is set using the acquired cold reference position coordinate data. When the line is operating and a high-temperature cast slab is being conveyed on the conveying line, hot reference position coordinate data and hot measured shape data are acquired by light section method. The acquired hot measured shape data is converted into corrected data using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data, and feature quantities indicating the shape characteristics of the cast slab are calculated using the converted corrected data. Therefore, the influence of errors due to disturbances including heat and vibration can be reduced even during operation, and the shape of the cast slab being conveyed on the conveying line can be inspected with high accuracy. Furthermore, since the required equipment can be provided at a lower cost than conventional shape measuring devices, it is possible to reduce the cost of introducing equipment used for shape inspection.

[0059] Although the present invention has been described above using embodiments, the present invention is not limited to the configuration of these embodiments. The scope of the present invention is determined by the description in the appended claims, and within that scope, all configurations that omit, modify, or improve upon some of the components shown in the embodiments are included in the present invention. The independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference, as long as they do not contain mutually exclusive requirements.

[0060] For example, in this embodiment, an imaging trigger is output to the first camera 10 from the second camera 20 or an external device when the transport distance of the cast slab becomes equal to the line pitch of the line laser. By accumulating measurement data while shifting the most recently measured three-dimensional shape of the cast slab by a distance equal to the line pitch of the line laser, the three-dimensional shape of the cast slab can be measured.

[0061] Furthermore, in this embodiment, the slab weight may be estimated from the measured cross-sectional shape and transport distance, and the slab cutting length may be corrected. Alternatively, the target slab cutting length may be determined from the currently measured cross-sectional shape by statistically analyzing the three-dimensional shape of the slab in the past, the final product length, and one of the transport distance, slab temperature, or slab weight, so as to minimize the cutting loss of the final product.

[0062] Furthermore, in this embodiment, the number of surfaces on which the shape of the cast slab can be measured may be increased by placing another set of 3D cross-sectional dimension measurement systems diagonally or opposite the cast slab.

[0063] Furthermore, although the cast slab in this embodiment is a billet, the present invention is also suitably applicable to shape inspection of cast slabs and blooms, which have a rectangular cross-sectional shape.

[0064] Furthermore, although this embodiment shows a configuration in which only one first camera is placed to measure and inspect the shape of two sides of the cast slab, two sets of first cameras and laser devices may be placed in approximately symmetrical positions on either side of the cast slab to measure and inspect the shape of all four sides of the cast slab. This would allow for more accurate calculation of the volume per unit length of the cast slab, among other benefits.

[0065] (Note 1) The slab shape inspection method is a slab shape inspection method for inspecting the shape of a slab with a square cross-section manufactured by continuous casting on a conveying line in which the slab is being transported along the longitudinal direction of the slab while it is at a high temperature, and comprises a reference coordinate system setting step in which cold reference position coordinate data, which is the position coordinate data of multiple points on two linear materials stretched parallel to the transport direction of the slab, is acquired by light sectioning method when the line is stopped and the slab is not on the conveying line, and a reference coordinate system setting step in which a reference coordinate system is set using the acquired cold reference position coordinate data, and when the high-temperature slab is being transported on the conveying line The process includes a step of calculating a feature quantity that, while the line is in operation, acquires hot reference position coordinate data, which is position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is position coordinate data indicating the shape of the cast slab, by light sectioning; converts the acquired hot measurement shape data into corrected data, which is position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration; and calculates a feature quantity that indicates the shape characteristics of the cast slab using the converted corrected data.

[0066] (Note 2) The method for inspecting the shape of the cast slab is as follows: In Note 1, the cold reference position coordinate data is obtained by, with the line stopped, using laser beams R from three line laser devices that are perpendicular to the transport direction and parallel to each other with respect to the two linear materials. n [n=1, 2, 3] were irradiated, and six points (o n , p n The position coordinate data of the two linear materials and the two adjacent sides S of the cast slab in the line operation state. m For [m=1, 2], laser light is irradiated from the three line laser devices, and the six points on the two linear materials that are irradiated by the laser light (o n ', p nThe hot measurement step includes acquiring position coordinate data of ') as the hot reference position coordinate data and acquiring position coordinate data of the linear region on the two sides of the cast slab irradiated with the laser light as the hot measurement shape data; a matrix creation step includes creating the correction transformation matrix based on the cold reference position coordinate data and the hot reference position coordinate data; and a data correction step includes converting the hot measurement shape data into correction data using the correction transformation matrix.

[0067] (Note 3) In the method for inspecting the shape of a cast slab, as described in Note 2, the reference coordinate system setting step includes setting a straight line passing through two points (o1, o3) on one of the two linear materials and one point (p1) on the other linear material as the X-axis, setting a Y-axis perpendicular to the X-axis, and setting a Z-axis perpendicular to the X-axis and the Y-axis, wherein the reference coordinate system is a Cartesian coordinate system determined by the X-axis, the Y-axis and the Z-axis.

[0068] (Note 4) The slab shape inspection method, in Note 2 or Note 3, the matrix creation step is based on the cold reference position coordinate data obtained using the three line laser devices, namely the first line laser device, the second line laser device, and the third line laser device, and generates a cold first vector, a cold second vector, and a cold third vector (o n ,p n ) is set, and based on the hot reference position coordinate data obtained using the first line laser device, the second line laser device and the third line laser device, the first hot vector, the second hot vector and the third hot vector (o n ',p n ') set, and the cold first vector, the cold second vector and the cold third vector (o n ,p n ) are the first hot vector, the second hot vector, and the third hot vector (o n ',p n The first, second, and third correction transformation matrices, which convert to '), are created as the correction transformation matrices.

[0069] (Note 5) In the method for inspecting the shape of the cast slab, as described in Note 4, the feature quantity calculation step is performed by using the two side surfaces (S) obtained by the light section method. m ) Point cloud data on (B m By transforming ) using the least squares method, the first hot data approximation curve (C), which is a curve in a two-dimensional plane, is obtained as the hot measurement shape data. (n,1) ) and the second hot data approximation curve (C (n,2) The steps include calculating the first hot data approximation curve (C) using the first correction transformation matrix, the second correction transformation matrix, and the third correction transformation matrix. (n,1) ) and the second hot data approximation curve (C (n,2) By converting ) into the curve of the reference coordinate system, the first corrected approximation curve (C' (n,1) ) and the second corrected approximation curve (C' (n,2) The steps include calculating the first corrected approximation curve (C' (n,1) ) and the second corrected approximation curve (C' (n,2) By projecting ) onto the YZ plane (X=0) of the aforementioned reference coordinate system, the first projection approximation curve (D (n,1) ) and the second projection approximation curve (D (n,2) ) is obtained, and the first projection approximation curve (D (n,1) ) and the second projection approximation curve (D (n,2) By converting ) into an approximate line using the least squares method, the first approximate line (E (n,1) ) and the second approximation line (E (n,2) This includes the step of obtaining ), The aforementioned feature quantities are (1) Straightness at position n, (2) Amount of swelling at position n, (3) Amount of indentation at position n, (4) Rhombus shape at position n, (5) Degree of twist at position 2, (6) Warping at position 2, and (7) Curve at position 2 Includes at least one of the following: Here, (1) the degree of linearity at position n is the first approximate line (E (n,1)The first projection approximation curve (D) for ) (n,1) The standard deviation of the distance of the second approximation line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is the standard deviation of the distance between the two points. (2) The amount of bulge at position n is the first approximate line (E (n,1) The first projection approximation curve (D) for ) (n,1) ) twice the maximum distance on the bulging side and / or the second approximate line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is twice the maximum distance on the bulging side. (3) The amount of indentation at position n is the first approximate line (E (n,1) The first projection approximation curve (D) for ) (n,1) ) twice the maximum distance on the recessed side and / or the second approximate line (E (n,2) The second projection approximation curve (D) for ) (n,2) This is twice the maximum distance on the indented side of ) (4) The rhomboidity at position n is the first approximate line (E (n,1) ) and the second approximate line (E (n,2) This is the value obtained by subtracting 90° from the angle θ made by ) (5) The degree of twist at position 2 is the first approximate line (E (n,1) ) and the second approximate line (E (n,2) Let F(n) be the angle bisector of the angle between F(1) and F(2). F(n) is the average value of the relative angle φ1 between F(1) and F(2) and the relative angle φ2 between F(2) and F(3). (6) The curvature at position 2 is the first approximate straight line (E (n,1) The midpoint of the line segment of the portion of the linear region corresponding to the aforementioned linear region is e (n,1) to, e (1,1) and e (3,1) A straight line passing through and e (2,1) When e1 is the intersection point of the line passing through and parallel to the Y-axis, (2,1) This is the distance between and e1. (7) The curvature at position 2 is the second approximate straight line (E (n,2) The midpoint of the line segment of the portion of the linear region corresponding to the aforementioned linear region is e (n,2) to, e (1,2) and e(3,2) A straight line passing through and e (2,2) When e2 is the intersection point of a line passing through and parallel to the Z-axis, then e (2,2) This is the distance between and e2.

[0070] (Note 6) The method for inspecting the shape of the cast slab further includes a distance measurement step in Note 5 for measuring the transport distance of the cast slab, wherein the three line laser devices are arranged at equal intervals along the transport direction of the cast slab, and the transport distance is measured by the laser beam R n Each time the interval equals the interval, the feature calculation step is performed, and the (1) linearity at position n, (2) bulge at position n, (3) indentation at position n, and (4) rhombicity at position n are calculated as a weighted average of the values ​​obtained by performing the feature calculation step multiple times.

[0071] (Note 7) The slab shape inspection method includes the step of outputting an alarm if the absolute value of at least one of the feature quantities exceeds a predetermined threshold, as described in Note 5 or Note 6.

[0072] (Note 8) The slab shape inspection device is for inspecting the shape of a slab with a square cross-section manufactured by continuous casting on a conveying line in which the slab is being transported along the longitudinal direction of the slab while at a high temperature, and comprises two linear members arranged along the transport direction of the slab, and laser beam R at equal intervals along the transport direction to the two sides of the slab and the two linear members. nThe system comprises three line laser devices arranged to irradiate the surface of the two linear materials and the slab, the irradiation area which is the area irradiated by the laser light from the three line laser devices, and a control device connected to the three line laser devices and the light-cutting camera device, wherein the control device acquires cold reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, by light sectioning in a line stop state where the slab is not on the transport line, and sets a reference coordinate system using the acquired cold reference position coordinate data, and the high-temperature casting The system is configured to perform the following steps: while the slab is being transported on the conveyor line, hot reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is the position coordinate data indicating the shape of the slab, are acquired by the optical section method; the acquired hot measurement shape data is converted into corrected data, which is the position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration; and a feature quantity calculation step is performed to calculate feature quantities that indicate the characteristics of the shape of the slab using the converted corrected data.

[0073] (Note 9) The slab shape inspection device is for inspecting the shape of a slab with a square cross-section manufactured by continuous casting on a conveying line in which the slab is being transported along the longitudinal direction of the slab while at a high temperature, and comprises two linear members arranged along the transport direction of the slab, and laser beam R at equal intervals along the transport direction to the two sides of the slab and the two linear members. nThe system comprises three line laser devices arranged to irradiate, a light sectioning camera device arranged such that the irradiation area, which is the area on the surface of the two linear materials and the slab irradiated by the three line laser devices, falls within the imaging range, a distance measuring camera device arranged to acquire an image of at least one side of the slab, and a control device connected to the three line laser devices, the light sectioning camera device and the distance measuring camera device, wherein the control device acquires cold reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, by light sectioning in a line stop state where the slab is not on the transport line, and sets a reference coordinate system using the acquired cold reference position coordinate data, and the distance measuring The process includes a distance measurement step in which the transport distance of the cast slab is measured based on an image captured by a camera device, and a feature quantity calculation step in which, while the high-temperature cast slab is being transported on the transport line, hot reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is the position coordinate data indicating the shape of the cast slab, are acquired by light sectioning method, the acquired hot measurement shape data is converted into corrected data, which is the position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration, and feature quantity calculation step in which feature quantities indicating the shape characteristics of the cast slab are calculated using the converted corrected data, and the measured transport distance is measured by the laser beam R n It is configured to be executable each time the interval equals the specified interval. [Explanation of Symbols]

[0074] 10. Camera 1 20. Second camera 30 Laser devices 50 Control device 100, 200 Water string

Claims

1. A method for inspecting the shape of a cast slab with a square cross-section, manufactured by continuous casting, on a conveying line in which the cast slab is transported along the longitudinal direction of the cast slab while it is at a high temperature, In a line-stopped state where the cast slab is not on the conveying line, cold reference position coordinate data, which is the position coordinate data of multiple points on two linear materials stretched parallel to the conveying direction of the cast slab, is acquired by light sectioning, and a reference coordinate system is set using the acquired cold reference position coordinate data; In a line operation state in which the high-temperature cast slab is being transported on the conveyor line, hot reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is the position coordinate data indicating the shape of the cast slab, are acquired by light section method. The acquired hot measurement shape data is converted into corrected data, which is the position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration. A feature quantity calculation step is performed to calculate a feature quantity indicating the shape characteristics of the cast slab using the converted corrected data. A method for inspecting the shape of a cast slab, including the following:

2. The aforementioned cold reference position coordinate data is In the line stopped state, laser beams R are emitted from three line laser devices perpendicular to the transport direction and parallel to each other, onto the two linear materials. ｎ [n=1, 2, 3] were irradiated, and six points (o) on the two linear materials were obtained by the light section method. ｎ , p ｎ This is the position coordinate data of ) The feature calculation step described above is: In the line operation state, the two linear materials and the two adjacent side surfaces S of the cast slab ｍ For [m=1,2], laser light is irradiated from the three line laser devices, and the six points on the two linear materials that are irradiated by the laser light (o ｎ ', p ｎ A hot measurement step in which the position coordinate data of ') is acquired as the hot reference position coordinate data, and the position coordinate data of the linear region on the two sides of the cast slab irradiated with the laser light is acquired as the hot measurement shape data, A matrix creation step of creating the correction transformation matrix based on the cold reference position coordinate data and the hot reference position coordinate data, A data correction step in which the hot measurement shape data is converted into the corrected data using the correction transformation matrix. A method for inspecting the shape of a cast slab according to claim 1, including the following:

3. The aforementioned reference coordinate system setting step is: In a plane including two points (o １ , o ３ ) on one of the two linear members and one point (p １ ) on the other linear member, a straight line passing through the two points (o １ , o ３ ) on the one linear member is set as the X-axis, a Y-axis orthogonal to the X-axis is set, and a Z-axis orthogonal to the X-axis and the Y-axis is set, including The method for inspecting the shape of a cast slab according to claim 2, wherein the reference coordinate system is a Cartesian coordinate system defined by the X-axis, the Y-axis, and the Z-axis.

4. The aforementioned matrix creation step is, Based on the cold reference position coordinate data obtained using the three line laser devices, namely the first line laser device, the second line laser device, and the third line laser device, the cold first vector, the cold second vector, and the cold third vector (o ｎ , p ｎ Set ) and Based on the hot reference position coordinate data obtained using the first line laser device, the second line laser device, and the third line laser device, a first hot vector, a second hot vector, and a third hot vector (o ｎ ', p ｎ Set ') and The cold first vector, the cold second vector and the cold third vector (o ｎ , p ｎ ) are the first hot vector, the second hot vector, and the third hot vector (o ｎ ', p ｎ The method for inspecting the shape of a cast slab according to claim 2, wherein a first correction transformation matrix, a second correction transformation matrix, and a third correction transformation matrix that convert to ') are created as the correction transformation matrix.

5. The feature calculation step described above is: The two sides (S) obtained by the light section method ｍ ) Point cloud data on (B ｍ By transforming ) using the least squares method, the first hot data approximation curve (C), which is a curve in a two-dimensional plane, is obtained as the hot measurement shape data. （ｎ，１） ) and the second hot data approximation curve (C （ｎ，２） The steps to calculate ) and Using the first correction transformation matrix, the second correction transformation matrix, and the third correction transformation matrix, the first hot data approximation curve (C （ｎ，１） ) and the second hot data approximation curve (C （ｎ，２） By converting the above into a curve of the reference coordinate system, the first corrected approximation curve (C') is used as the correction data. （ｎ，１） ) and the second corrected approximation curve (C' （ｎ，２） The steps to calculate ) and The first corrected approximation curve (C' （ｎ，１） ) and the second corrected approximation curve (C' （ｎ，２） By projecting ) onto the YZ plane (X=0) of the aforementioned reference coordinate system, the first projection approximation curve (D （ｎ，１） ) and the second projection approximation curve (D （ｎ，２） ) and the first projection approximation curve (D （ｎ，１） ) and the second projection approximate curve (D （ｎ，２） By converting ) into an approximate line using the least squares method, the first approximate line (E （ｎ，１） ) and the second approximate line (E （ｎ，２） The steps to obtain ) Includes, The aforementioned feature quantities are (1) Straightness at position n, (2) Amount of swelling at position n, (3) Amount of indentation at position n, (4) Rhombus shape at position n, (5) Degree of twist at position 2, (6) Warping at position 2, and (7) Curve at position 2 Includes at least one of the following: Here, (1) the degree of linearity at position n is the first approximate straight line (E （ｎ，１） The first projection approximation curve (D （ｎ，１） The standard deviation of the distance of the second approximate line (E （ｎ，２） The second projection approximation curve (D （ｎ，２） This is the standard deviation of the distance between the two points. (2) The amount of bulge at position n is the first approximate line (E （ｎ，１） The first projection approximation curve (D （ｎ，１） ) twice the maximum distance on the bulging side and / or the second approximate line (E （ｎ，２） The second projection approximation curve (D （ｎ，２） This is twice the maximum distance on the bulging side. (3) The amount of indentation at position n is the first approximate line (E （ｎ，１） The first projection approximation curve (D （ｎ，１） ) twice the maximum distance on the concave side and / or the second approximate line (E （ｎ，２） The second projection approximation curve (D （ｎ，２） This is twice the maximum distance on the indented side of ) (4) The degree of rhombicity at position n is the first approximate line (E （ｎ，１） ) and the second approximate line (E （ｎ，２） This is the value obtained by subtracting 90° from the angle θ made by the two sides. (5) The degree of twist at position 2 is the first approximate line (E （ｎ，１） ) and the second approximate line (E （ｎ，２） Let F(n) be the angle bisector of the angle between F(1) and F(2), and F(n) is the average value of the relative angle φ1 between F(1) and F(2) and the relative angle φ2 between F(2) and F(3). (6) The curvature at position 2 is the first approximate straight line (E （ｎ，１） The midpoint of the line segment of the portion of the linear region corresponding to the aforementioned linear region is e （ｎ，１） toshi, e （１，１） and e （３，１） A straight line passing through and e （２，１） The intersection point of the line passing through and parallel to the Y-axis is e. １ e （２，１） and e １ It is the distance between, (7) The curvature at position 2 is the second approximate straight line (E （ｎ，２） The midpoint of the line segment of the portion of the linear region corresponding to the aforementioned linear region is e （ｎ，２） toshi, e （１，２） and e （３，２） A straight line passing through and e （２，２） The intersection point of the line passing through and parallel to the Z-axis is e. ２ e （２，２） and e ２ The distance between, The method for inspecting the shape of a cast slab according to claim 4.

6. Furthermore, the method includes a distance measurement step for measuring the transport distance of the cast slab. The three line laser devices are arranged at equal intervals along the transport direction of the cast slab. The transport distance is the laser beam R ｎ Each time the interval becomes equal to the interval, the feature calculation step is performed. The method for inspecting the shape of a cast slab according to claim 5, wherein the (1) linearity at position n, (2) bulge at position n, (3) dent at position n, and (4) rhombicity at position n are calculated as a weighted average of values ​​obtained by performing the feature quantity calculation step multiple times.

7. The process includes the step of outputting an alarm if the absolute value of at least one of the aforementioned features exceeds a predetermined threshold. The method for inspecting the shape of a cast slab according to claim 5.

8. A cast slab shape inspection device for inspecting the shape of a square-shaped cast slab manufactured by continuous casting, on a conveying line in which the cast slab is transported along the longitudinal direction of the cast slab while at a high temperature, Two linear members are arranged along the conveying direction of the cast slab, Along the aforementioned transport direction, at equal intervals, laser beam R is directed at the two sides of the cast slab and the two linear materials. ｎ Three line laser devices positioned to irradiate, A light-cutting camera device is positioned such that the irradiation area, which is the region on the surface of the two linear materials and the cast slab irradiated with laser light by the three line laser devices, falls within the imaging range. The control device connected to the three line laser devices and the light-cutting camera device. Equipped with, The control device is In a line-stopped state where the cast slab is not on the conveyor line, cold reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, is acquired by light sectioning, and a reference coordinate system is set using the acquired cold reference position coordinate data. In a line operation state in which the high-temperature cast slab is being transported on the conveyor line, hot reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is the position coordinate data indicating the shape of the cast slab, are acquired by light section method. The acquired hot measurement shape data is converted into corrected data, which is the position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration. A feature quantity calculation step is performed to calculate a feature quantity indicating the shape characteristics of the cast slab using the converted corrected data. A cast slab shape inspection device configured to perform the following.

9. A cast slab shape inspection device for inspecting the shape of a square-shaped cast slab manufactured by continuous casting, on a conveying line in which the cast slab is transported along the longitudinal direction of the cast slab while at a high temperature, Two linear members are arranged along the conveying direction of the cast slab, Along the aforementioned transport direction, at equal intervals, laser beam R is directed at the two sides of the cast slab and the two linear materials. ｎ Three line laser devices positioned to irradiate, A light-cutting camera device is positioned such that the irradiation area, which is the region on the surface of the two linear materials and the cast slab irradiated with laser light by the three line laser devices, falls within the imaging range. A distance measuring camera device positioned to acquire an image of at least one side of the cast slab, Control devices connected to the three line laser devices, the light cutting camera device, and the distance measuring camera device, Equipped with, The control device is In a line-stopped state where the cast slab is not on the conveyor line, cold reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, is acquired by light sectioning, and a reference coordinate system is set using the acquired cold reference position coordinate data. A distance measurement step of measuring the transport distance of the cast slab based on an image captured by the distance measuring camera device, In a line operation state in which the high-temperature cast slab is being transported on the transport line, hot reference position coordinate data, which is the position coordinate data of multiple points on the two linear materials, and hot measurement shape data, which is the position coordinate data indicating the shape of the cast slab, are acquired by light sectioning. The acquired hot measurement shape data is converted into corrected data, which is the position coordinate data on the reference coordinate system, using a correction transformation matrix created using the cold reference position coordinate data and the acquired hot reference position coordinate data to correct measurement errors due to disturbances including heat and vibration. A feature quantity calculation step is performed to calculate a feature quantity indicating the shape characteristics of the cast slab using the converted corrected data, and the measured transport distance is measured by the laser beam R n A cast slab shape inspection device configured to be operational each time the interval becomes equal to the specified interval.

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