JPS5965709A - Method for measuring thickness profile of strip edge part - Google Patents

Abstract

PURPOSE:To measure the thickness distribution of a strip edge part in an on- line system with high accuracy by converting the radiant rays passed through the strip edge part into electric signals and applying an averaging process to these electric signals. CONSTITUTION:The radiant rays passed through a strip 10 and attenuated are converted into beams through a slip-shaped scintillator 16. These beams are condensed by an optical lens 18 to be coincident with the irradiating surface of an image sensor 20 for photoelectric transfer and then amplified by a preamplifier 22 to be converted into video signals. These video signals are transmitted to an arithmetic device 26. Both almost edge part information on both edges and the thickness profile information on the edge part which are calculated by the device 26 receive the necessary processing in response to the applications and are delivered to a display device 28 for monitor of operators. The dense sampling of 500 times per millisecond cycle, for instance, is carried out to the information on a detection system (including the scintillator 16, the lens 18 and the sensor 20) to obtain signal trains. These signal trains are averaged to reduce greatly the effect of short-cycle noises.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the thickness profile of a strip edge, particularly in a tantem rolling process in a thin plate rolling plant or in a processing line such as coil unwinding or weighing. The present invention relates to a force method for measuring the thickness profile of a strip edge, suitable for use in measuring the thickness profile of a section (from the extreme edge to the order of 100 mtn).

Generally, the thickness profile of the edge portion of a thin copper plate is one of the important quality control items. For example, an index indicating the thickness profile of the strip edge, called edge drop, is not uniquely defined, but is usually used as shown in the first article (from the edge drop of the strip 10 to the tip of the edge). For example, the thickness at the position of 10 questions) and the thickness at the position of !2 fnun (for example, 50 v, m
) indicates a difference of 6 from the thickness of In addition, in the case of cold-rolled silver plate,
It is customary to ship the silver plate with the thickness at a position A v,m, (A varies depending on the destination of the silver plate, for example, 10 mm) from the edge as a guaranteed value. For some delivery destinations,
It is also called TMW material and is traded by calculated weight by specifying the lower limit thickness of a specific part of the edge part. In any case, there is a very high need to accurately measure the thickness profile of the strip edge. For example, in order to measure the thickness profile over the entire width of a hot-rolled steel plate, two sets of thickness measuring devices, a fixed type and a scanning type, are installed together, and the fixed type thickness measuring device is
S) The thickness of the central part of the IJ knob is measured, while the scanning thickness measuring device mechanically drives its thickness detection part in the width direction of the IJ knob to measure the thickness in the width direction. Methods for measuring thickness profiles and methods for measuring thickness at multiple locations in the sheet width direction using three or more radiation sources have already been put into practical use; It was difficult to know the thickness distribution of the strip edge. This is due to the following reasons.

(1) The main purpose of the above method is to obtain the thickness profile of the entire board in the width direction of strip crowns, etc., and the measurement method is not limited to only the edges.

(2) The diameter of the radiation beam is 10 to 15 mmψ or thicker.
However, it is not possible to measure the fine thickness distribution with a resolution in the width direction of 2 to 3111 m or less, which is necessary for measuring the thickness profile of the edge portion.

(3) When the radiation beam is narrowed down to a small diameter so as to obtain a widthwise resolution of 2 to 3 mm or less, the signal/noise ratio (referred to as S/N ratio) after passing through the strip becomes lower and thicker. It is difficult to obtain an accuracy of approximately ±0.1% of the measured plate thickness, which is required for thickness measurement.

Therefore, conventionally, the thickness measurement of edge portions such as edge drops has had to rely on manual sampling measurements by inspectors, and the reality is that online measurements have not yet been put into practical use.

Therefore, for example, in the automatic plate thickness control device in a cold rolling tandem mill, control is based on the signal from a thickness gauge that measures the thickness at the center of the strip, so the thickness at the edge Regarding the profile, it is only possible to control it during rolling by estimating the value based on actual data, and in some cases, it may cause defective products due to insufficient thickness of the edge part or decrease in yield due to insufficient thickness of the edge part. There were quite a few things that happened.

The present invention was made to solve the above-mentioned conventional drawbacks, and it is possible to measure the thickness distribution of the strip edge part online.
The purpose of the present invention is to provide a method for measuring the thickness profile of a stop edge portion with high accuracy.

In the present invention, when measuring the thickness profile of a strip edge, radiation is irradiated toward the strip edge, and the radiation transmitted through the strip edge is converted into thickness profile information using a radiation-electrical signal conversion means including an image sensor. The above object was achieved by converting the strip edge into an electrical signal containing both the strip edge position information and the edge position information, and calculating the thickness profile of the strip edge portion from the information obtained by averaging the electrical signal. It is something.

The radiation-to-electrical signal conversion means may include a strip-shaped scintillator that converts radiation transmitted through the strip edge portion into light, an optical lens that collects light emitted from the strip-shaped scintillator, and an optical lens that collects light emitted from the strip-shaped scintillator. By comprising an image sensor that converts light focused by a lens into an electrical signal, it is possible to perform highly accurate measurements using a single image sensor.

Alternatively, by configuring the radiation-electric signal conversion means as a radiation-sensitive image sensor,
This allows electrical signal conversion to be performed in one step.

Furthermore, the averaging process for the electric signal is performed by performing dense sampling and digital filtering using the average value, so that highly accurate averaging process is performed.

The present invention has the following features: (1) strip-shaped scintillators have been put to practical use and are commercially available; (2) if the radiation beam is focused or the strip-shaped scintillators are used, the S/N ratio of the obtained signal decreases; By reducing responsiveness and increasing the amount of information, effective S/
This was done with the focus on the following: (3) the ability to improve the N ratio; and (3) the ability to easily obtain positional information in the width direction of the strip using an image sensor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration example of an apparatus for measuring a thickness profile of a cold-rolled steel plate edge portion, in which a method for measuring a thickness profile of a strip edge portion according to the present invention is adopted, will be described in detail below with reference to the drawings.

This device is arranged at both edges of the strip 10 as shown in FIG.
A collimator 14 emits radiation (
a radiation source 12 for emitting radiation (e.g. a strip-shaped scintillator 16 that converts light into light, and the strip-shaped scintillator 1
6. An optical lens 18 for condensing the emitted light, and converting the light condensed by the optical lens 18 into an electrical signal.
A radiation-to-electrical signal conversion means, which may also be a single image sensor 20, a preamplifier 22 for amplifying the extremely weak electrical signal output from the image sensor 20 into a video signal, and width information of the striker 921100 are set. and a setting device 24 for controlling the radiation source 12 and the radiation-to-electrical signal conversion means according to the output of the setting device 24.
The preamplifier 22 is positioned at the edge of the preamplifier 22.
The edge of the strip and the edge of the strip are determined from the information obtained by densely sampling the output video signal several hundred times or more and applying averaging processing to the digital filtering using the average value. The apparatus is comprised of a calculation device 26 for determining the thickness profile of the calculation device 26, and a display device 28, such as a CRT, for displaying the output of the calculation device 26.

The radiation source 12, collimator 14, strip-shaped scintillator 16, optical lens 18, image sensor 20, and preamplifier 22 are stored in a detection head installed immediately after the cold rolling tandem mill or in an unwinding inspection line.

The action will be explained below.

According to the width information of the strip 10 preset in the setting device 26, the radiation source 12, the collimator 14, the strip scintillator 16, the optical lens 18, and the image sensor 2
The detection head, including the preamplifier 1o and the preamplifier 22, is previously positioned at the edge of the strip 1o. strip 1o
When it reaches the detection head, the IJ knob 1o
The attenuated radiation transmitted through the strip-shaped scintillator 16
It is converted into light by the optical lens 18 and then sent to the image sensor 20 by the optical lens 18.
The light is focused so as to match the irradiation surface, and photoelectric conversion is performed. Since the signal is extremely weak as it is, it is amplified by the preamplifier 22 and converted into a video signal, which is then transmitted to the arithmetic unit 26.

Here, the strip-shaped scintillator 16 is used in 2 to 3.
This is to obtain a thickness profile with a resolution of 3 mm or less, but since the dose incident on each scintillator is small, the SIN ratio is worse than that of a normal radiation thickness meter. In order to obtain information on the thickness distribution of the edge part, etc., it is not necessary to quickly obtain the information on the thickness at the center of the strip. The effective S/N ratio is improved by increasing the detection system (strip scintillator 16, optical lens 18).
, image sensor 20), for example, 500 times at a period of 1 millisecond, and by averaging the resulting signal sequence, the effect of short-period noise can be significantly reduced. In this case, if the sampling time (integration time) is 0.5 seconds, and the calculation time in the arithmetic unit [26] is 0.5 seconds, the response time of the device will be approximately 1 second in total. It can function satisfactorily as a.

The edge part information of both edge parts and the edge part thickness profile information calculated in this way are processed by the calculation device 26 as necessary according to the purpose, and are used for monitoring by the operator. , is output to the display device 28. The display device 28 displays, for example, the thickness of a portion 10 mm away from the edge, the difference in thickness between 10 mm and 150 mm from the edge drop, and if the thickness of the central portion is If given, it is possible to display strip crowns, etc.

In the above configuration example, the strip-shaped scintillator 16, the optical lens 18, and the image sensor 20 are used as the radiation-to-electrification code conversion means to convert the radiation into light once and then convert it into an electrical signal again. Since the light is converted, it is possible to focus the light on the optical lens 18.
A radiation-to-electrical signal conversion means can be configured with a single image sensor 20. Note that the configuration of the Hokuryoku-electrical signal conversion means is not limited to this, and for example, it is also possible to perform the radiation-electrical signal conversion at one time using the radiation-sensitive image sensor 1. In this case, since an optical system such as an optical lens cannot be used, it may be necessary to use a plurality of image sensors.

Next, an embodiment of an automatic plate thickness control device for a cold rolling tandem mill, in which the strip edge thickness profile measuring device according to the invention is employed, will be described in detail.

In this embodiment, as shown in FIG. 3, the first stand 32-1
~Cold rolling tandem mill 30 with fifth stand 32-5
, the thickness t of the central part of the strip 10. In addition to the conventional thickness gage 34 that measures the thickness of the strip, an edge thickness profile measuring device 36 according to the present invention is installed to measure not only the thickness te of the central portion of the strip output from the thickness gage 34 but also the Edge profile signal t output from edge thickness profile measuring device 36. Automatic plate thickness control device (AGC)
(referred to as a device) 38 for automatic plate thickness control. In the figure, 40 cm is a tension reel.

In this embodiment, the thickness profile te of the edge part is constantly monitored online, and when a thickness variation that causes overthinning or overthickness occurs, the target thickness of the AGC device 38 is automatically set (at the center of the strip). ) to correct the thickness of the edge.

That is, in FIG. 3, the target plate thickness is given to the AGC device 38 in advance. and the thickness at the center of the strip to
The signals from the conventional thickness gage 34 are compared and calculations are performed to bring the actual thickness closer to the target thickness h0.
-4 rolling roll speeds v3 and v4 are △v3 and △, respectively.
Output a control signal to change v4 (fifth stand 32-
5 is a pivot stand). As a result, the tension applied to the strip 10 between the third and fourth stands 32-3 and 32-4 and between the fourth and fifth stands 32-4 and 32-5 is changed, and the thickness of the strip 10 is changed. Make corrections.

Now, when the signal 1e from the edge thickness profile measuring device R36 exceeds the edge thickness target value given in advance, the AGC device 38 reduces the previous thickness target value h0 by Δho. Then, control is started using (ho-Δha) as the new target value. This allows the thickness of the edge portion to return to a normal range. Conversely, when the thickness te of the edge portion falls below a predetermined target value, the control opposite to the above is executed. In this way, it is possible to maintain not only the thickness 1 at the center (but also the thickness t8 at both edges) to the target value, thereby preventing the occurrence of defective products due to insufficient thickness at the edges of the strip 10. In addition, it is possible to prevent a decrease in yield due to excessive thickness of the edge portion.

The above embodiment is an example in which the edge thickness profile measuring device according to the present invention is incorporated into an automatic sheet thickness control device in a cold rolling tandem mill. - An inspection device that measures the thickness of the edge portion using a horizontal line or the like and outputs rejected portions due to excessive thinness etc. on a report sheet is also possible. In addition, it is also possible to monitor edge drops by installing the edge thickness profile measurement device according to the present invention in the finishing mill blood drain of a hot rolling sheet plant, instead of in a cold rolling plant or °. .

Furthermore, since it is possible to measure the thickness profile with minute resolution according to the present invention, it is also possible to use the present invention to monitor an edge drop adding device for cold-rolled double-width rolled material. . That is, as shown in Fig. 4, when the coil is rolled with a double width (a combination of different widths is also possible) in a cold rolling tandem mill (No. 41)) and then slit to obtain a coil of a predetermined width (Fig. (C)), before the slit, Fig. 4 (
As shown in B), it is necessary to make an indentation on the slit part and add a thickness distribution corresponding to the edge drop for the operation of the subsequent process.
2 is used. At this time, the thickness distribution of the indented part by the edge drop adding device 42 is measured using the method for measuring the thickness profile of the strip edge part according to the present invention, and when the thickness distribution deviates from the desired profile, the thickness distribution is measured manually or automatically. By changing and modifying the settings of the edge drop adding device 42, a desired edge profile can be obtained.

As described above, the present invention has the excellent effect that the thickness distribution of the strip edge portion can be measured online with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an edge drop at a strip edge, and FIG. 2 is a configuration example of an edge thickness profile measuring device in which the method for measuring the thickness profile of a strip edge according to the present invention is adopted. FIG. 3 is a block diagram showing the configuration of an embodiment of an automatic sheet thickness control device for a cold rolling tandem mill in which the above device is adopted, and FIG. FIG. 2 is a process diagram showing the process of manufacturing cold-rolled double-width rolled material to which the thickness profile measurement method can be applied. 10...Strip, 12...Radiation assembly source, 14...
・Collimator, 16...Strip type scintillator, 18・
...Optical lens, 20...Image sensor, 22...
・Preamplifier, 24... Setting device, 26... Arithmetic device, 28... Display device, 30... Cold rolling tandem mill,
32-1 to 32-5...1st to 5th stands, 36.
... Edge thickness profile measuring device, 38... Automatic plate thickness control device. Agent Takaya Ron (and 1 other person) Figure 1

Claims (4)

[Claims] (1) When measuring the thickness profile of the strip edge portion, (S) irradiates radiation toward the IJ strip edge portion, and converts the radiation that has passed through the strip edge portion into a radiation-to-electrical signal converter including an image sensor to measure the thickness. The thickness profile of the strip edge portion is determined from the information obtained by converting the strip profile information and edge position information into an electrical signal and performing averaging processing on the electrical signal. How to measure the thickness profile of a strip edge. (2) The radiation-to-electrical signal converting means comprises (s) a strip-shaped scintillator that converts radiation transmitted through the IJ edge portion into light, an optical lens that collects light emitted from the strip-shaped scintillator, and the optical The method for measuring the thickness profile of a strip edge portion according to claim 1, comprising an image sensor that converts light focused by a lens into an electrical signal. (3) The method for measuring the thickness profile of a strip edge portion according to claim 1, wherein the radiation-electrical signal converting means is a radiation-sensitive image sensor. (4) The averaging process for the electrical signal is
' The method for measuring the thickness profile of a strip edge portion according to claim 1, wherein the method is performed by performing IJ and digital filtering using an average value.