JPS6253043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the cross-sectional shape of steel plates and other plate materials. Generally, in the process of rolling a steel plate, the cross-sectional shape of the rolled steel plate is measured, and the rolling conditions are determined from this cross-sectional shape to control the rolling process. Conventionally, an apparatus as shown in FIG. 1 has been used to measure the cross-sectional shape of such steel plates. That is, reference numeral 1 denotes a frame, which is configured to be moved by a scanning drive mechanism 2 at a predetermined scanning speed in the width direction of a plate material to be measured, such as a steel plate 3.
This frame 1 is provided with a radiation source 4, and a radiation beam is irradiated from this radiation source 4 toward the steel plate 3. Further, this frame 1 is provided with a radiation detector 5, and this radiation detector 5
is opposed to the radiation source 4 via the steel plate 3. The radiation beam emitted from the radiation source 4 is configured to pass through the steel plate 3 and enter the radiation detector 5. When this radiation beam passes through the steel plate 3, it is attenuated in accordance with the thickness of the steel plate 3, so the thickness of the steel plate 3 is detected by detecting the dose with the radiation detector 5 and determining the attenuation of the radiation beam. can. Since the radiation source 4 and the radiation detector 5 are moved in the width direction of the steel plate 3 by the scanning drive mechanism 2, the thickness in the width direction of the steel plate perpendicular to the longitudinal direction of the steel plate is continuous during measurement when the steel plate is stopped. In addition, in the measurement when the steel plate is running, the plate thickness in the diagonal direction with respect to the longitudinal direction (travel direction) of the steel plate is continuously determined as the pseudo thickness in the width direction. is required. By the way, in order to increase the resolution of such a cross-sectional plate thickness shape, the radiation beam must be made as sharp as possible. However, when this radiation beam is narrowed down, the radiation dose decreases, and statistical noise caused by the radiation source increases, impairing measurement accuracy. For this reason, in the past, it was not possible to make the radiation beam very sharp, and there was a limit to the improvement of resolution and accuracy. Further, for example, when a scratch occurs on a rolling roll, small protrusions 6 are formed on the surface of the steel plate 3 as shown in FIG. However, such a detection signal of the small protrusion 6 cannot be distinguished from a single noise added from the outside. For this reason, conventionally, the presence of a small protrusion 6 had to be determined only when a signal corresponding to such a small protrusion 6 was consistently received over multiple scans; There was a problem in that the occurrence of the protrusions 6, that is, the detection of abnormalities in the rolling rolls was delayed, resulting in a large number of defective products. The present invention has been made based on the above-mentioned circumstances, and its object is to obtain an apparatus that can accurately and reliably measure the cross-sectional thickness shape of a plate material. The present invention will be explained below with reference to an embodiment shown in FIG. In the figure, reference numeral 101 denotes a frame, which has a substantially U-shape. The frame 101 is configured to be moved by a scanning drive mechanism 102 at a predetermined scanning speed in the width direction of a plate material, such as a steel plate 103, to be measured. A radiation source 1 is provided at the bottom of this frame 101.
04 is provided, and a radiation beam 105 is emitted from this radiation source 104 toward the steel plate 103. Further, this frame 101 is provided with a plurality of radiation detectors 106...
These radiation detectors 106... are the steel plates 103
The radiation source 104 faces the radiation source 104 through. These radiation detectors 106 . . . are arranged in a straight line, and the arrangement direction matches the scanning drive direction of the frame 101. and,
Radiation beam emitted from the radiation source 104
105 is transmitted through the steel plate 103 to each radiation detector 1
06... is configured to be incident. The unit radiation beams 105a that are incident on each of the radiation detectors 106 are sharp beams so as to obtain sufficient resolution. Each of these radiation detectors 106 outputs a signal corresponding to the amount of incident radiation, and these signals are each sent to a signal processing circuit 107. Further, the scanning drive mechanism 102
From there, a position signal corresponding to the scanning position of the frame 101 is sent to the signal processing circuit 107. Moreover, this signal processing circuit 107
The measurement distance (measurement width direction distance) of each radiation detector is input in advance from the distance in the scanning direction from the measurement reference point set on the frame 101 to each radiation detector 106 . In this signal processing circuit 107, the scanning drive circuit 102
Find the scanning speed at that time from the position signal sent from the reference point, divide the measured distance from the reference point to each radiation detector 106 by this scanning speed, and calculate the measurement time difference for each radiation detector 106... do. Then, the signals sent from each of the radiation detectors 106 are shifted so as to cancel out the measurement time difference, and the signal levels are averaged and combined into one signal. Then, the cross-sectional shape of the steel plate 103 is determined from the combined signal and the position signal, and the recording and display mechanism 108 records and displays this. One embodiment of the present invention configured as described above has a radiation beam 105 emitted from a radiation source 104.
When transmitted through the steel plate 103, it is attenuated in accordance with the thickness of the steel plate 103, and each radiation detector 106...
It is incident on... And each radiation detector 106...
outputs a signal corresponding to the incident radiation dose,
This signal is sent to a signal processing circuit 107 and synthesized, and the thickness of the steel plate 103 at the position through which this radiation beam 105 has passed is measured. These radiation sources 104 and radiation detectors 106 are scanned together with the frame 101 by the scanning drive mechanism 102, and the thickness of the steel plate 103 in the width direction is continuously measured, and the cross-sectional thickness shape of the steel plate 103 is is required. And this one is for each radiation detector 1
06... Unit radiation beam 105a... incident on...
... can be made sufficiently sharp to increase resolution,
Furthermore, even if the beam is sharpened in this way, the accuracy will not be reduced, and defects such as small protrusions caused by scratches on rolling rollers can be reliably detected. The reason will be explained below. That is, by sharpening the radiation beam incident on the radiation detector, the resolution can be increased, but as described above, on the other hand, statistical noise increases and accuracy decreases. By the way, in this embodiment, a plurality of radiation detectors 106... are arranged in the scanning direction, so each radiation detector 106... passes through a position corresponding to an arbitrary measurement position on the steel plate 103. Times vary. These time differences are calculated from the measurement reference point as described above to each radiation detector 106...
It is equal to the measurement time difference obtained by dividing the distance to ... by the scanning speed. Therefore, each radiation detector 106...
By shifting the signals from each other by the measurement time difference and averaging them, these time-shifted signals can be combined into a single signal. As a result, in measurements when the steel plate is stopped, a composite plate thickness signal can be obtained, for example, by arithmetic averaging of multiple signals at the same position in the width direction of the steel plate, which is approximately perpendicular to the longitudinal direction of the steel plate, and in measurements when the steel plate is running. In this case, a pseudo composite plate thickness signal is obtained by, for example, arithmetic averaging a plurality of signals at the same position in the width direction of the steel plate in a diagonal direction with respect to the longitudinal direction of the steel plate. By the way, since the above-mentioned statistical noise originates from the radiation source 104 side, it enters each radiation detector 106 at the same time.
However, since the signals from these radiation detectors 106 are synthesized after being shifted by different measurement time differences, the statistical noise that enters at the same time is averaged, and if the number of radiation detectors 106 is N, then it is 1. /√ decreases. Therefore, even if the unit radiation beams 105a are sharpened to increase the resolution and, on the other hand, increase the statistical noise, the influence of this statistical noise is reduced, so there is no loss of accuracy. In addition, since external noise also enters each radiation detector 106 at the same time, its influence is reduced in the same way as above, and it becomes easy to distinguish the signal from the signal corresponding to the small protrusion mentioned above. This allows early detection of abnormalities in the rolling rolls. Note that the present invention is not limited to the above embodiment. For example, the signals from each radiation detector are not necessarily averaged after being shifted by the measurement time difference, but they are also stored until the end of scanning for each radiation detector, and the signals from each radiation detector are The face plate thickness shapes may be obtained, and these may be synthesized by shifting them corresponding to the distances from the measurement reference point to each radiation detector. However, in this case, it is assumed that the moving speed of the scanning drive mechanism 102 is stored or that the moving speed of the scanning drive mechanism 102 and the measured distance of each radiation detector maintain a constant relationship. Further, it may be possible to measure the crown of the steel plate during rolling by combining it with a fixed thickness gage that measures the thickness of the central portion of the steel plate in the width direction. Further, the present invention is applicable not only to steel plates but also to general cross-sectional plate thickness shape measuring devices for aluminum plates and other plate materials. As described above, the present invention arranges a plurality of radiation detectors in the scanning direction, and synthesizes the signals from these radiation detectors by shifting them temporally or graphically using a signal processing circuit. Therefore, noises that simultaneously enter each radiation detector, such as statistical noise caused by the radiation source and noise from the outside, are averaged, and their influence is reduced. Therefore, even if the resolution is increased by sharpening the radiation beam, the increase in statistical noise due to the sharpening of the beam can be reduced, and the resolution can be increased without compromising accuracy. Furthermore, since the influence of external noise is reduced, small protrusions that may be confused with external noise can be detected reliably, which has great effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional example, and FIG. 2 is a sectional view of a plate material. FIG. 3 is a schematic diagram of an embodiment of the present invention. 101... Frame, 102... Scanning drive mechanism, 103... Steel plate (plate material), 104... Radiation source, 106... Radiation detector, 107... Signal processing circuit.

Claims (1)

[Claims] 1. A radiation source that emits radiation, a plurality of radiation detectors arranged in a straight line facing this radiation source through a plate to be measured, and the radiation source and the radiation detector arranged in the arrangement direction of the radiation detectors. A scanning mechanism is used to shift the output of each radiation detector based on the speed of movement by this scanning mechanism and the measurement distance of the radiation detector to obtain data at the same position in the width direction of the plate material, and data at the same position in the width direction of the board is obtained. 1. An apparatus for measuring the cross-sectional thickness shape of a plate material, comprising: a signal processing circuit that synthesizes the data of and obtains the cross-sectional shape of the plate material.