JPH01320419A - Method for measuring bent shape in lengthwise direction of hot-rolled material - Google Patents

Abstract

PURPOSE:To highly accurately measure the bent shape of a hot-rolled material in the lengthwise direction in corresponding to various bent shapes by taking the image of the material formed by self-emitting light rays from the side face of the tip of the material carried on a carrying table with a two-dimensional image sensor. CONSTITUTION:A two-dimensional image sensor 14 takes the image of the tip 12A of a rolled material 12 carried on a carrying table 10 by taking self-emitting light rays of the material 12 from the side face of the tip 12A at a photographing point in the vicinity of the tip 12A, at which the optical axis 14A of the sensor is in the same plane with the material 12 and intersects the center line 10A of the table 10 in the widthwise direction at right angles. A picture processor 16 processes the signal of the taken 14 picture of the tip 12A and calculates parameters of the bent shape of the material 12. Therefore, the distance D to a bend starting point J, maximum down-bent quantity G, and the distance H from the maximum down-bent point L to the point J are calculated as the parameters as shown in (a) of the figure and outputted to a host computer 38. Therefore, not only the bend control is performed by simply feeding back the bent quantity, but also the operation is improved by statistically analyzing the bends in many rolled examples and reflecting the analyzed result to the presetting of the rolling machine and cooling water quantity.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for measuring the warpage shape of a rolled material in the longitudinal direction during hot rolling, and in particular, the warpage shape of the rolled material during hot rough rolling is captured as a continuous profile, and the warpage shape is accurately measured. Concerning how to measure. [Conventional technology]

The rough rolling equipment in the continuous hot rolling equipment rolls slabs in order to supply sheet bars of a predetermined thickness to the finishing rolling mill.
Warpage in the longitudinal direction may occur at the tip and/or tail end of the rolled material due to differences in friction coefficients between the upper and lower sides of the work roll and the rolled material. This warping of the longitudinal ends of the rolled material increases as the amount of warpage increases, which not only reduces the product yield, but also damages the conveyor roll or rolling roll if it warps downward. The rolled material itself is also damaged, resulting in a defective product. If the warpage is even more significant, the passing of the material to be rolled through the rolling mill may be hindered, and the rolling equipment may be damaged. In particular, in recent years, hot rolling equipment often uses equipment such as edge heaters to heat both ends of the rolled material in the width direction, and in order to protect these equipment and fulfill the intended functions. It is also necessary to perform rolling control to eliminate the warpage. As a prerequisite for such control, it is necessary to accurately measure the shape of warp in the longitudinal direction of the longitudinal end of the rolled material. As a method for measuring this warp shape, for example,
Methods for detecting warp in the longitudinal direction of a rolled material have been proposed as disclosed in Japanese Patent Application Laid-open No. 135408, Japanese Patent Application Laid-Open No. 59-16625, and Japanese Patent Application Laid-Open No. 62-297711. The sheet warpage detection method disclosed in Japanese Patent Application Laid-Open No. 58-135408 includes a radiation source and a radiation detection device that detects the amount of radiation transmitted through the rolled material on the exit side of the rolling mill. The plate warp angle is detected based on the difference in the amount of radiation transmitted between the flat part and the warp part of the rolled material. The method for detecting warpage of a rolled material disclosed in JP-A-59-16625 is as follows: [At least two distance meters are provided along the conveyance direction on the exit side of the rolling mill, and one surface of the tip of the rolled material is provided. It measures the distance to each distance meter, and detects warpage of the rolled material based on the output of the distance meter. The warpage detection method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-297711 captures the timing when the tip or tail end of a rolled material passes a detection point arbitrarily set on a table in hot rolling equipment, and The projected distance of the rolled material is measured from above using an image sensor, and the height of the tip or tail of the rolled material is detected using the principle of triangulation, thereby detecting upward warpage. . (Problems to be Solved by the Invention) By the way, the warpage of the rolled material is caused by the following problems in Figs.
There are various shapes as shown in ). For example, Fig. 9(a) shows an upward curvature, Fig. 9(b) shows a downward curvature, and Fig. 9(C) and (d) show a combination of an upward curvature and a downward curvature. Regarding warpage, it is impossible to express the shape of the warp simply by using only one parameter such as the warp angle or the height of the front and rear ends. That is, the board warp detection method proposed in Japanese Patent Application Laid-open No. 58-135408 has the problem that the shape of warp is expressed only by one parameter, the warp angle, and it is not possible to distinguish between upward warpage and downward warpage. . Furthermore, in a region where the plate warp angle, which is actually important, is small, the change in the amount of radiation transmitted due to the change in the plate warp angle is slight, and high-precision measurement cannot be performed in principle. That is, when the plate warpage angle is θ, the apparent plate thickness is i/cos θ times as much as when the plate warp is zero, but for example, when θ = 5°, l/cos θ-1°0038. can be,
There is a problem in that the reliability of the measurement results based on the above-mentioned plate warp angle is extremely low when considering longitudinal variations in the thickness of the rolled material. Furthermore, in the method for detecting warpage of a plate disclosed in the above-mentioned Japanese Patent Application Laid-open No. 59-16625, at least two distance meters are provided in the conveying direction. Considering the length of the section, only a few rangefinders can be installed at most. Therefore, the warpage of the rolled material is only measured at several points in the longitudinal direction of the material, and it is impossible to measure the warpage in accordance with the various warp shapes as shown in FIG. 9. Furthermore, the method for detecting plate warpage disclosed in Japanese Patent Application Laid-Open No. 62-297711 expresses the warpage of a rolled material using only one parameter, the height of its longitudinal end. For this reason, it is not possible to measure the downward warpage of the rolled material. Furthermore, it is naturally impossible to measure various complicated warped shapes as shown in FIG. [Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and provides a method for adjusting the longitudinal warpage of the longitudinal ends of a rolled material in hot rolling to correspond to various warpage shapes. It is an object of the present invention to provide a method for measuring warp shape in the longitudinal direction of a rolled material during hot rolling, which enables highly accurate measurement. (Means for Solving the Problems 1) The present invention collects an image of the side surface of the rolled material on the outlet side of the hot rough rolling mill.As a result of experiments, the image of the rolled material has sufficient brightness due to self-luminescence. This was done based on the knowledge that it can be separated from the background and there is no need to provide an external light source.As shown in Fig. An image of one longitudinal end of the rolled material is taken near the one end using a two-dimensional image sensor whose optical axis is on the same horizontal plane as the rolled material and perpendicular to the center line in the width direction of the conveying table. At the point, take a photo using the self-luminous light on the side of the one end,
The above purpose is achieved by extracting the contour of the one end from the image obtained by this photography, calculating a parameter representing the warped shape of the one end from this contour, and measuring the warped shape from this parameter. .

[Function] According to the present invention, a two-dimensional image sensor installed at one longitudinal end of the material to be rolled on the same horizontal plane as the material to be rolled captures an image of self-luminous light from the side surface of the material to be rolled. The outline of one end of the material to be rolled is extracted from the image, and this outline is analyzed to obtain parameters representing the warped shape. That is, since the warped shape is captured as an image, even if the warped shape is complex, it can be accurately understood from the parameters. [Example] Hereinafter, a method for measuring the longitudinal warp shape of a rolled material in hot rolling according to the present invention will be described in detail with reference to drawings showing an apparatus for carrying out the method. As shown in FIGS. 2 and 3, this device allows an optical axis 14A to capture an image of the tip of a rolled material 12 being conveyed on a conveying table 10 in a hot rolling facility (not shown in its entirety). At a photographing point that is on the same horizontal plane as the material to be rolled 12, is orthogonal to the center line 10A in the width direction of the conveying table 10, and is near the tip 12A of the material to be rolled 12, the tip 1
A two-dimensional image sensor 14 that photographs by self-luminous light from the side surface of the tip MW 12A processes the signal of the image of the tip 12A photographed by this two-dimensional image sensor 14, and
and an image processing device 16 that calculates the parameters of the warp shape. As shown in FIG. 4, the image processing device 16 includes two
A10 converter 18 which converts the signal from the dimensional image sensor 14 into an A/D converter. ! :, an image memory 20 for recording the image signal digitized by the A/D converter 18, and an output switch 22 for switching between the direct image signal from the A/D converter 18 and the image in the image memory 20. and converts the digital image □□□ from this output switch 22 into a video signal.
A D/A converter 24 that performs /A conversion, and this D/A converter 2
A monitor 26 for displaying an image converted into an analog by 4.
and a photographing timing generation circuit 28 that outputs a signal for photographing the side surface of the rolled material 12 at an appropriate timing.
and an address generation circuit 30 for storing the image data in the image memory 20 in an orderly and appropriate timing for each process, or for reading the image data in order to send it to each circuit; A binarization circuit 32 binarizes the original image captured by the two-dimensional image sensor 14 and stores it again in the image memory 20, and a binarization circuit 32 converts the original image captured by the two-dimensional image sensor 14 into the image memory 20, and converts the rolled image from the binarized image stored in the image memory 20. A contour extraction circuit 34 that extracts the contour of the tip 12A of the material 12
A parameter calculation circuit 36 calculates warpage shape parameters from the contour extracted by the contour extraction circuit 34, and outputs the calculated parameters to the upper calculation R38, or outputs various setting values or measurements of the rolling schedule used when calculating the parameters. Interface circuit 40 for inputting values
and a timing controller 42 that sends control signals to each processing circuit in order to perform processing in each processing circuit in an orderly manner.
It consists of and. The photographing timing generating circuit 28 optimizes the timing of photographing by the two-dimensional image sensor 14 so that the side surface of the rolled material 12 is at the position of the tip 12A and the warped portion of the tip is entirely covered in the image. It generates a photographing timing signal. This timing signal can be generated by using a cold metal detector (CMD), a hot metal detector (HMD), etc. to determine when the tip 12A of the rolled material 12 has reached the photographing point, or by using a cold metal detector (CMD), a hot metal detector (HMD), etc. Rolled material 1
2 is detected, the tip 12A of the rolled material 12 is
A method of repeatedly capturing an image and detecting whether or not the tip 12A of the material to be rolled 12 is located at an appropriate position in the image until the timing is appropriate, etc. Choose any one of these methods. The binarization circuit 32 calculates a threshold value for binarization from the image of the side surface of the tip 12A of the rolled material 12 stored in the image memory 20, converts the grayscale image into a binary image, and stores it in the image memory again. 20. The contour extraction circuit 34 extracts "
By tracing the boundary between the "white area" and the "black area," a contour image is extracted and stored in the image memory 20. The parameter calculation circuit 36 calculates the tip DWi of the rolled material 12 from the contour image extracted by the contour extraction circuit 34.
12 A parameter representing the warped shape at A is calculated, and a plurality of parameters are calculated as necessary. For example, as shown in FIG. 5, in addition to the continuous warp H from the tip point I of the rolled material 12, the curvature of the warp, the distance from the tip point I of the rolled material 12 to the warp starting point J. D, maximum upward curvature ME, distance F1 between the maximum upward curvature point and the curvature starting point J
Parameters such as the maximum downward curvature IG and the distance H between the maximum downward curvature point and the curvature starting point J are determined. Here, when calculating each of the parameters, in order to obtain the warp 1 at the actual size, the two-dimensional image sensor 14 and the rolled material 1 are used.
You will need some distance between you and 2. This distance can be determined by inputting the set value or measured value W of the width of the material to be rolled 12 from the host computer 38 through the interface circuit 40 as shown in the following equation. L=β-W/2 ・・・・・・・・・(1
) Here, β is the distance between the two-dimensional image sensor 14 and the width direction center line 10A of the transport table 10, and is a known value. The address generation circuit 30 reads data from the image memory 20 in order for each process of each circuit and sends it to each circuit,
It is also used to store processed data in the image memory 20, to take in data from the A/D converter 18 in an orderly manner, or to send data in the image memory 20 to the D/A converter 24 in an orderly manner. be. Further, the timing controller 42 is for sending control signals to each circuit in order to perform processing in each circuit in an orderly manner. The output switch 22 switches between the raw image sent from the A/D converter 18 and the image stored in the image memory 20, and the monitor 2-6 monitors the progress and results of the processing. It is for observation. The host computer 38 takes in the parameters calculated by the parameter calculation circuit 36 via the interface circuit 40, and based on these parameters, individually controls the circumferential speed of the upper and lower work rolls of the rolling mill, and controls the speed of the rolled material. 1
The warping of the rolled material 12 is controlled by individually controlling the cooling conditions of the rolled material 12 on the front and back surfaces to create a humidity difference. Next, the rolled material 1 in the hot rolling equipment is processed using the above device.
A case in which the warped shape of No. 2 is measured will be explained. First, as shown in step 101 in FIG.
An image of the side surface of 2A due to self-emission is photographed by the two-dimensional image sensor 14. Photographed by this two-dimensional image sensor 14, A/
The signal digitized by the D converter 18 is taken into the image memory 20 and stored in accordance with the optimum timing signal from the photographing timing generation circuit 28. The image of the tip 12A stored in the image memory 20 is
It is binarized by the binarization circuit 32 and sent to the image memory 20 again.
is stored in This binarized image shows the rolled material 12 in "black" as shown in FIG. The contour extraction circuit 34 stores in the image memory 20 2 (see step 102 in FIG. 1 for extracting the contour of the rolled material 12 from the illi image) stored in the image memory 20 . This contour image becomes as shown in FIG. It can be seen from FIG. 7 that the rolled material 12 to be measured has a downwardly warped shape as shown in FIG. 9(b). The parameter calculation circuit 36 calculates parameters representing the warped shape of the rolled material 12 based on the extracted contour image (see step 103 in FIG. 1). As a parameter, as shown in FIG.
The distance D from to the warp start point J, the maximum downward warp IG, and the distance H from the maximum downward warp point to the warp start point J are calculated,
This is the upper level calculation via the interface circuit 40.
8 is output. That is, the method not only measures the warp m in each part of the rolled material 12, but also captures the shape of the warp, classifies the warp according to this shape, and calculates parameters representing the shape of the warp. Therefore, instead of simply controlling the warpage by feeding back the amount of warpage, it is necessary to statistically analyze the warpage in many rolling examples and reflect it in the presets of the rolling mill and cooling water m to improve operations. be able to. In addition, although the above-mentioned example measures the warped shape at the tip 12A of the rolled material 12, the present invention is not limited to this, and the warped shape at the tail end or both the tip and the tail end of the rolled material 12 is measured. It also applies when measuring. Further, in the above embodiment, the two-dimensional image sensor 14 is placed on the exit side of the rough rolling mill, but it may be placed on the entry side in reverse rolling, the entry side of the next rolling mill, etc. You may also do so. Effects of the Invention 1 Since the present invention is configured as described above, it is possible to measure the warpage in the longitudinal direction of the longitudinal end of the rolled material in hot rolling with high accuracy in correspondence with various warp shapes. It has the excellent effect of being able to

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the gist of the method for measuring the longitudinal warp shape of a rolled material during hot rolling according to the present invention, Fig. 2 is a plan view showing an apparatus for carrying out the method of the present invention, and Fig. 3 is a front view of the same, FIG. 4 is a block diagram showing the image processing device in the fixing device, FIG. 5 is a side view showing the relationship between the warped shape of the rolled material and the parameters, and FIG. A binarized diagram showing a digitized image of the rolled material, FIG. 7 is a contour diagram of the rolled material extracted from the binarized diagram, and FIG. 8 is a diagram showing the relationship between the contour diagram and parameters. FIG. 9 is a side view showing various warped shapes of the rolled material. DESCRIPTION OF SYMBOLS 10... Conveyance table, 10A... Width direction center line, 12... Rolled material, 12A... Tip, 14... Two-dimensional image sensor, 14A... Optical axis, 16... Image processing device, 20... Image memory, 32... Binarization circuit, 34... Contour extraction circuit, 36... Parameter calculation circuit, 38... Upper paralysis machine.

Claims (1)

[Claims] (1) An image of one longitudinal end of a rolled material being transported on a transport table in a hot rolling facility, where the optical axis is on the same horizontal plane as the rolled material, and the center line in the width direction of the transport table. A two-dimensional image sensor that is orthogonal to the image sensor takes a picture of the side surface of the one end at a shooting point near the one end using self-emission, extracts the outline of the one end from the image obtained by this imaging, and extracts the outline of the one end from this outline. A method for measuring warp shape in the longitudinal direction of a rolled material during hot rolling, comprising calculating a parameter representing the warp shape of the one end, and measuring the warp shape from this parameter.