JPH0781847B2 - Method for measuring the planar shape of hot rolled steel sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the planar shape of a hot rolled steel sheet such as a thick plate or a hot rolled steel strip, and in particular, it has a planar shape for enabling optimum measurement for advantageously improving the yield. It is intended to propose a measurement method for making the measured value of 1) closer to the actual plane shape of the steel sheet.

A steel sheet hot-rolled by a rolling mill is conveyed to a shear line and sheared to a predetermined size. In this shearing process, various shearing devices are used, and in the case of a thick plate, a shear, a side shear, an end shear, etc. shears the tip, tail end and both ends of the steel plate. In such a shearing process, how to reduce the loss of the shearing allowance from the as-rolled steel plate (hereinafter referred to as an "as-rolled plate") is important for aiming at high yield and high efficiency production. There is a demand for optimal measurement in the process.

[0003]

2. Description of the Related Art In order to measure a product from an azroll plate with a good yield and efficiency, various methods for measuring the planar shape of an azroll plate and measuring methods have been developed and actually used. As a planar shape measuring method, there is a method using a backlight type width meter shown in FIG.
In addition to this, there is a method of determining the traveling width by measuring the amount of reflected light (see Japanese Patent Laid-Open No. 172203/1982). There is also a method of measuring the width dimension by detecting the radiant energy generated from the high temperature slab material in the rolling line.

[0004]

In order to perform optimum measurement so as to reduce the loss of the shearing allowance, the measured value of the plane shape for use in the measurement, which is measured by a plane shape meter, should be as actual as possible. The key point is to match the planar shape of the plate. That is, the side edge portion of the hot-rolled steel sheet has a defective shape portion caused by the metal flow in the width direction during rolling.
The most important point is to understand the planar shape within the range where both surface quality and plate thickness are guaranteed.

However, in the measurement using the conventional flat shape measuring instrument, no consideration is given to distinguish the defective shape portion of the side edge portion of the above-mentioned as-roll plate, and the plate width including such defective shape portion is taken into consideration. I was measuring. For this reason, it is the actual situation that the planing measurement is performed by using the plane shape data having a large error as the effective dimension that can be measured. For example, in the planar shape data measured by the backlight width meter shown in FIG. 2, there is an error (β in the figure) of about 5 mm at one end face. If such planar shape data is used, incorrect measurements will be taken, and there will be a great deal of happiness in products containing defective shapes.Therefore, it is necessary to perform measurements with margins on the side edges, and thus the planar shape data. Despite the development and use of the measurement method using, there was a limit that could not be the optimum measurement.

Plane shape measurement of hot-rolled steel sheet capable of accurately measuring the margin of the shape defect portion of the side edge portion in order to perform optimum measurement using plane shape data (effective plane shape data) considering the shape defect portion of the side edge portion. It is an object of the invention to propose a method.

[0007]

Means for Solving the Problems This invention is to measure the plane shape of a hot-rolled steel sheet after hot rolling and before measuring and shearing, by irradiating light from a light projector toward a side edge portion of the hot-rolled steel sheet, The intensity distribution of the reflected light in the width direction of the steel plate is measured by a light receiver, and the width direction length of the defective shape portion at the side edge portion of the hot rolled steel plate due to the change in the width direction of the reflected light based on the difference in reflectance. It is a method for measuring the planar shape of a hot-rolled steel sheet, which comprises:

[0008]

The defective shape of the side edge of the hot-rolled steel sheet mainly occurs during rolling, and the surface is rough because it does not come into contact with the rolling rolls, and the intensity of reflected light is weak because light is diffusely reflected.
On the other hand, the area other than the defective shape portion comes into contact with the rolling roll and is pressed down, so that the surface roughness is small and the reflected light intensity of light is strong. This invention detects the difference in the reflected light due to the difference in the roughness of the steel plate surface and the angle with the reflecting surface, and detects the boundary position between the shape-defective portion and the non-shape-defective region, and the shape defect of the hot-rolled steel sheet. The shape and size of the part are obtained. Since the shape dimension of the defective shape portion can be grasped in this way, it is possible to perform optimum measurement by using the planar shape data in which the defective shape is folded. Similarly, the black skin residue on the side edge of the steel plate can be detected by the difference in reflected light.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 shows a schematic diagram of an example of a method for measuring the planar shape of a hot-rolled steel sheet according to the present invention, and FIG. 3 shows a block diagram as an example of the configuration of the planar shape measuring apparatus used in the present invention. As shown in FIG. 1, light is emitted from a light projector 8 toward a side edge portion of the hot-rolled steel sheet 1, and the reflected light is measured by a light receiver 9 in the plate width direction, and the defective shape portion 2 and the other areas 7 are measured. The boundary 3 between and is calculated.

Therefore, as shown in FIG. 3, the shape-defective boundary measuring device 23 comprises a light emitter 8, a light receiver 9, a shape-defective boundary position calculating section 10, and a shape-defective dimension calculating section 12. Light is emitted from an arbitrary position toward a side edge portion of the hot-rolled steel sheet 1 from a light projector 8 and reflected light from the surface of the hot-rolled steel sheet 1 is detected by a light receiver 9. The output of the light receiver 9 is input to the boundary position calculation unit 10 for the defective shape, and the region 7 in contact with the rolling roll
Since the surface roughness is greatly different at the boundary 3 with the shape defect part 2 which is not in contact with the rolling roll, the boundary 3 is extracted by detecting the difference in reflected light, and the boundary position data 11 is output. The boundary position data 11 is input to the dimension calculation unit 12 for defective shape,
In synchronization with the position data 14 of the end 4 measured by the planar shape meter 13 (position matching in the hot-rolled steel sheet 1), the data 15 of the widthwise length 6 of the defective shape portion is obtained. Then, the data 15 of the length 6 in the width direction of the defective shape portion and the planar shape data 16 are input to the shape dimension correction calculation unit 17 of the defective shape portion to be corrected and calculated, and the effective length except the length in the width direction of the defective shape portion is valid. Planar shape data 17 is obtained. The effective plane data 18 is input to the measurement calculation unit 19 and used for the optimum measurement calculation, and the measurement data 20 is obtained. Thus, it is possible to perform optimum measurement using the effective plane shape data 18 in which the widthwise length 6 of the defective shape portion is corrected.

In the case of detecting the black-skin remaining, the shape defect boundary position calculating section 10 becomes the black-skin remaining calculating section, and the boundary position data 11 becomes the black-skin measurement data and becomes an external output signal.

The boundary measuring device 23 for defective shape detects the boundary position of defective shape on the side edge of the hot-rolled steel sheet by utilizing the difference in the amount of reflected light.
It is not limited to one per side edge, and a plurality of units can be provided. Further, the number of light emitters and light receivers per unit is not limited. The light receiver 9 uses an image sensor, and a line and area type camera is used. In addition, the planar shape meter 13 can be any known planar shape meter.

FIG. 4 shows an embodiment of the present invention. With respect to the vertical line of the region 7 of the hot-rolled steel plate 1 that was in contact with the rolling roll, light was projected by the light projector 8 from an angle inclined by 45 degrees toward the side edge portion, and this reflected light was provided in the vertical line direction of the steel plate. The light is received by the light receiver 9. In this case, the output waveform of the light receiver 9 showing the change in the intensity of the reflected light traveling from the end portion in the width direction of the steel sheet to the central portion has a waveform as shown in FIG. Such a light receiver 9
The light reception waveform of the output of is input to the boundary position calculation unit 10 of the defective shape, and the boundary position of the defective shape portion is detected. As the calculation method, as shown in FIG. 5, the end face boundary position may be calculated using a method of differentiating the received light waveform and detecting the point where the amount of received light changes most as the boundary position.

In the present invention, the waveform peaks 26 and 27 shown in FIG. 5 are calculated by the combination of the light projector 8 and the light receiver 9 to detect the boundary position and the edge (end) tip of the defective shape. To detect the edge (edge) tip portion, the light intensity change in the plate width direction can be emphasized at the edge portion also by utilizing the light from the lower light source 22 of the planar shape meter shown in FIG. .

[0015]

As described above, according to the present invention, the defective shape of the side edge of the hot rolled steel sheet is detected by the change in the intensity of the reflected light.
It has become possible to accurately measure the end surface boundary of a hot-rolled steel sheet without adversely affecting the complicated side edge shape defect. From this,
Taking the example of a thick plate, it is possible to perform optimum measurement using effective flat shape data, and it is also possible to automatically measure the black skin residue on the end face of the hot-rolled steel plate on the inspection line, resulting in high yield and high efficiency production. Greatly contribute to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an example of a method for measuring the planar shape of a hot-rolled steel sheet according to the present invention.

FIG. 2 is a schematic diagram of an example of a conventional planar shape measuring method.

FIG. 3 is a block diagram of an example of a configuration of a planar shape measuring apparatus used in the present invention.

FIG. 4 is a schematic diagram showing an example of the arrangement of a planar shape measuring apparatus used in the present invention.

FIG. 5 is a graph showing an example of a reflected light waveform in a light receiver.

[Explanation of symbols]

 1 Hot Rolled Steel Sheet 2 Defects in Shape 3 Boundaries between Shape Defects and Other Areas 4 Edges 5 Boundaries between Shape Defects and Other Areas 6 Length of Shape Defects in Width 7 Areas Other than Shape Defects 8 Emitter 9 Light receiver 10 Boundary position calculation unit for defective shape 11 Boundary position data 12 Dimension calculation unit for defective shape 13 Plane shape meter 14 Position data for edge 15 Width direction length data for defective shape 16 Plane shape data 17 Geometrical dimension correction calculation part of defective shape part 18 Effective plane data 19 Measuring calculation part 20 Measuring data 21 Plane shape meter detecting part 22 Bottom light source of planar shape meter 23 Boundary measuring device for defective shape 24 Steel plate area other than defective shape 25 Shape defect Boundary part 26 Peak point after differentiation 27 Waveform generated by disturbance of reflected light due to edge shape

Claims (1)

[Claims] 1. When measuring the planar shape of a hot-rolled steel sheet before hot-rolling and before measuring and shearing, light is emitted from a light projector toward the side edge of the hot-rolled steel sheet, and the reflected light is reflected in the width direction of the steel sheet. The intensity distribution is measured by a light receiver, and the width direction length of the defective shape portion at the side edge portion of the hot rolled steel sheet is calculated by the change in the width direction intensity of the reflected light based on the difference in reflectance, and the defective shape is obtained. A planar shape measuring method for hot-rolled steel sheet, which comprises measuring a planar shape excluding a portion.