JPH04273010A - Measurement of plate thickness of thick plate - Google Patents

Abstract

PURPOSE:To aquire a plate thickness measured value which is precise along the overall length of a thick plate in the rolled direction and good in absolute precision by correcting a detected signal of a thickness meter using a non- contact optical range finder by a gamma-ray thickness gauge. CONSTITUTION:At the time of measuring plate thickness of a thick steel plate 6 being rolled by a rolling mill 17, a measured value of a gamma-ray thickness gauge 1 which is good in absolute precision and a measured value of a thickness meter 3 using a non-contact optical range finder which is good in relative measuring precision of high speed sampling are input to a multipoint plate thickness arithmetic circuit 10. The multipoint plate thickness arithmetic circuit 10 high- speedily acquires a plate thickness measured value which is good in precision by correcting the measured value of the thickness meter 3 by the measured value of the gamma-ray thickness gauge 1. This corrected plate thickness is output as the plate thickness measured value.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for measuring the thickness of a thick steel plate, and in particular, in the rolling of a thick steel plate, for example, the thickness can be measured by obtaining detailed thickness measurements with good absolute accuracy over the entire length of a thick steel plate. The present invention relates to a method for measuring the thickness of a thick plate, which is suitable for use in controlling the thickness of a thick plate.

0002

2. Description of the Related Art Generally, in thick plate rolling, the thickness of a thick steel plate 6 is controlled while being rolled by a rolling mill facility having a universal rolling mill 17 as shown in FIG. 4, for example.

To control the plate thickness in this case, first, the thickness of the thick steel plate 6 is measured using a gamma ray thickness meter 1, and a signal 2 of the measured value is input to the plate thickness control section 15. A set plate thickness signal 20 is input to the plate thickness control section 15 from a control computer 19 for controlling the overall operation of the universal rolling mill 17. In addition, in FIG. 4, the code|symbol 18 shows a rolling line.

[0004] The plate thickness control section 15 controls the hydraulic rolling section 16 of the rolling mill 17 based on the input plate thickness measurement value and plate thickness setting value to obtain a target thickness of the thick steel plate 6. be able to do so. For this control, we basically use a gauge meter method that uses mill constants, rolling loads, roll opening measurements, etc.
Corrects the shortage of the absolute value of the plate thickness in plate thickness control using the input measured plate thickness.

[0005] In the above-mentioned rolling mill equipment, the responsiveness of plate thickness control is usually high, and the response capability is 90% per 0.1 seconds with a step input of 0.2 mm. In addition, the position detector for detecting the roll opening of the rolling mill has a high-speed response of 1 m (millisecond) or more.

However, the gamma ray thickness meter 1 used in the above-mentioned plate thickness measurement has a limitation in its measuring mechanism, in that it outputs an average plate thickness measurement value sampled at a certain time interval. Due to this restriction, the current technology requires a sampling time of at least 0.2 seconds in order for the gamma ray thickness meter 1 to measure with an accuracy that can be used as a correction value for plate thickness control. For example, in Japanese Patent Application Laid-Open No. 60-87902, a sampling time of 0.4 seconds is indicated in the lower right column of page 2.

[0007] That is, the rolling mill equipment has a diameter of 0.2 m as described above.
Since it has a high response of 90% per 0.1 seconds with m-step input, it has the ability to finely control the plate thickness over the entire length of the thick steel plate 6. However, the gamma ray thickness meter for correcting the lack of absolute accuracy of the plate thickness measurement value for plate thickness control outputs the average plate thickness measurement value at time intervals of 0.2 seconds or less.

Therefore, conventionally, the responsiveness of the gamma ray thickness meter used for correcting the plate thickness control has been extremely low compared to the responsiveness of the rolling mill equipment plate thickness control side.

[0009]

[Problems to be Solved by the Invention] As described above, conventionally, both the rolling mill control side and the gamma ray thickness meter side each have high accuracy, but it is difficult to measure the accuracy of thick plates such as rolled thick steel plates. There was a problem in that the plate thickness accuracy (for example, the amount of plate thickness deviation within the plate) was much lower than the target accuracy.

[0010] In connection with the present invention, the technology using a gamma ray thickness meter is disclosed in Japanese Patent Publication No. 107709/1983 and the above-mentioned Japanese Patent Application Laid-open No. 1983-107709.
This method has been proposed in Publication No. 87902 and the like. however,
All of the techniques proposed in these publications are techniques that attempt to improve thickness detection accuracy by using multiple gamma-ray thickness gauges, and are capable of improving the detection response of the gamma-ray thickness gauges. It's not technology. Therefore, this technique cannot solve the above problems.

The present invention was made in view of the above-mentioned conventional problems, and utilizes a non-contact optical distance meter that is fast and has good relative accuracy based on the plate thickness measurement value of a gamma-ray thickness meter that has good absolute accuracy. By correcting the measured values of the thickness gauge, it is possible to obtain detailed thickness measurements over the entire length of the plate with good absolute accuracy, and therefore it is possible to roll thick plates with high thickness accuracy. An object of the present invention is to provide a method for measuring the thickness of a thick plate.

0012

[Means for Solving the Problems] The present invention provides a gamma ray thickness meter,
The above-mentioned problem can be solved by using a thickness meter that uses a non-contact optical distance meter, correcting the measured value of the distance meter based on the measured value of the gamma ray thickness meter, and determining the plate thickness from the corrected measured value. This is to solve the problem.

[0013]

[Operation] In general, gamma ray thickness meters take a long time to measure (
For example, a sampling interval of 0.2 seconds) has a good absolute accuracy in plate thickness measurement (for example, an absolute accuracy of 28 μm in measuring a 20 mm plate thickness). In addition, thickness gauges using non-contact optical rangefinders have short measurement times (sampling time is 0.01 seconds, for example) and can perform high-speed measurements, and have good relative measurement accuracy, but it is difficult to compare the absolute accuracy of plate thickness measurement. Poor accuracy (e.g. 20m
There is an absolute accuracy of 150 μm in plate thickness measurement.

[0014] The present inventor took into account the characteristics of each thickness gauge, combined these thickness gauges, and determined the relative measurement accuracy of high-speed measurement using a thickness gauge using a non-contact optical distance meter. By correcting good measured values (measured data) with measured values (measured data) with good absolute accuracy measured with a gamma ray thickness meter, it is possible to obtain detailed plate thickness measurements with good absolute accuracy over the entire length of the plate. The present invention was created by focusing on the fact that

Next, the present invention will be explained using the rolling mill equipment shown in FIG. 1 as an example.

In the rolling equipment shown in FIG. 1, the thickness of a thick steel plate 6 is measured with a gamma-ray thickness meter 1, and a signal 2 representing the measured value of the plate thickness is inputted to a multi-point plate thickness calculation circuit 10. At the same time, the thickness of the thick steel plate 6 is measured using a thickness gauge 3 in which a non-contact optical rangefinder is placed opposite the thick steel plate 6 in a position sandwiching the thick steel plate 6.
A signal 4 of the plate thickness measurement value is input to the arithmetic circuit 10. Furthermore, apart from the plate thickness measurement as described above, the thick steel plate 6
The conveyance position is detected by the conveyance position detector 8, and the detected conveyance position signal 7 is inputted to the arithmetic circuit 10. The arithmetic circuit 10 performs the following arithmetic processing based on these input signals 2, 4, 7, etc.

That is, the arithmetic circuit 10 uses the input conveyance position signal 7 to match the thickness measurement position and measurement range in the rolling direction of the thick steel plate 6 between the thickness gauges 1 and 3. while performing calculation processing to correct the measured value of the thickness gauge 3 using the measured value of the γ-ray thickness gauge 1,
The calculation result is output to the plate thickness control section 15 as a plate thickness measurement value signal 11 of the thick steel plate 6. Note that this plate thickness control section 15 has the same function as the plate thickness control section 15 shown in FIG. 4 above.

[0018] Here, the content of the correction process is shown in FIG. 2, for example.
The explanation will be based on. In FIG. 2, the measurement value output timing of the thickness meter 3 using a non-contact optical distance meter is, for example, at a pitch of 0.01 seconds, and is indicated by symbols t1, t2, . . . in the figure. Furthermore, the measurement value output timing of the γ-ray thickness meter 1 is at a pitch that is 0.2 seconds apart from the sampling time, and is indicated by symbols a and b in the figure.
,···become that way. The arithmetic circuit 10 uses the transport position signal 7 to calculate the measured values t1, t2,
. . , and the rolling direction plate thickness measurement positions and measurement ranges between a, b, . . . are matched, and the plate thickness measurement values are corrected as follows.

That is, in the region I in FIG. 2, the difference Δx1 between the average value x1 of the measured values t3 to t23 of the thickness gauge 3 and the measured value a of the thickness gauge 1 is calculated as shown in the following equation (1). and the measured values t1 to t23 of the thickness gauge 3 using the difference Δx1.
is corrected as shown in the following equation (2), and the plate thickness measurement values t1' to t2 are obtained.
3' is output as signal 11.

[0020]

[Math 1]

In addition, in the region II in FIG. 2, the difference between the average value x2 of the measured values t24 to t43 of the thickness gauge 3 and the measured value b of the thickness gauge 1 is determined as shown in the following equation (3), and the corresponding Due to the difference Δx2, the measured value of the thickness gauge 3 is t24 to t4
3 is corrected as shown in the following equation (4) to obtain the plate thickness measurement value t24.
' to t43' as signal 11.

[0022]

[Math 2]

[0023] Also, in the area after III in Fig. 2, (1
) to (4).

According to the present invention, the thickness measurement value of a thick plate using a non-contact optical rangefinder is corrected using the plate thickness measurement value of a gamma-ray thickness meter with good absolute accuracy. It is possible to measure plate thickness over the entire length in detail, at high speed, and with high accuracy.

[0025]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

This embodiment is a rolling mill equipment, as shown in FIG. 3, in which the universal rolling mill 17 measures the thickness of a thick steel plate 6 according to the present invention to control the plate thickness.

The rolling mill equipment shown in FIG. 3 includes a hot rolled steel plate detector 12 for detecting the conveyance position of the thick steel plate 6 and inputting a signal 7 of the detected conveyance position to the multi-point plate thickness calculation circuit 10; A conveyance amount detector 13 is provided for detecting the conveyance amount of the thick steel plate 6 and inputting the detected conveyance amount to the multi-point plate thickness calculation circuit 10.

The other configurations are shown in FIGS. 1 and 4 above.
Components having the same configuration as those shown in FIG.

The operation of the embodiment will be explained below.

The multi-point plate thickness calculation circuit 10 calculates the output of the hot rolled steel plate detector 12 regarding the plate thickness measurement position and measurement range of the gamma ray thickness gauge 1 and the thickness gauge 3 using a non-contact optical distance meter. Matching is performed based on the conveyance position signal 7 and the conveyance amount output by the conveyance amount detector 13.

Next, as shown in FIG. 2, the γ
The correction calculation based on the measured plate thickness of the line thickness meter 1 is performed using the above (1) to (
4) and outputs the corrected plate thickness measurement value 11. The output corrected plate thickness measurement value is taken into the plate thickness control unit 15, and the control unit 15 controls the hydraulic pressure section 16 based on the corrected plate thickness measurement value taken in.

[0032] Therefore, the thickness of the thick steel plate 6 can be controlled over the entire length in the rolling direction with fine detail and high absolute accuracy.

As a result, the thickness deviation within the plate is approximately 20% lower than before.
%Diminished.

[0034] In the above embodiments, the present invention is applied to the measurement of the thickness of a thick steel plate rolled by rolling mill equipment as shown in Fig. 3, but the scope of implementation of the present invention is limited to this. It's not a thing. Plank thickness can be measured according to the present invention when rolling on various other rolling mills or when rolling other planks. Further, the correction method is not limited to equations (1) to (4) or FIG. 2, and other methods may be used.

[0035]

[Effects of the Invention] As explained above, according to the present invention, it is possible to obtain detailed plate thickness measurement values with good absolute accuracy over the entire length of a thick plate in the rolling direction. Therefore, if the plate thickness measurement value is used to control the plate thickness of a rolling equipment, an excellent effect can be obtained in that it becomes possible to roll a thick plate such as a thick steel plate with good plate thickness accuracy.

In order to investigate the effects of the present invention, the inventor measured the thickness of a thick steel plate using the conventional method and the method of the present invention, and corrected the rolling control using the measured values. As a result, the thickness accuracy of the plate thickness deviation in the thick steel plate after rolling is
In the conventional method, the thickness was 100 μm per 20 mm of plate thickness, but with the method of the present invention, it was 80 μm per 20 mm of plate thickness.
According to the present invention, the inner plate thickness deviation is reduced by about 20% compared to the conventional method. Therefore, it is understood that by utilizing the present invention, it is possible to roll a thick plate with high plate thickness accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram including a partial cross-sectional view for explaining a method for measuring the thickness of a thick plate according to the present invention.

FIG. 2 is a timing chart showing the detection timing of plate thickness of each thickness gauge.

FIG. 3 is a block diagram, including a partial cross-sectional view, showing the configuration of a thick steel plate rolling facility according to an embodiment of the present invention.

FIG. 4 is a block diagram, including a partial cross-sectional view, showing an example of the configuration of a plate thickness control device in a conventional rolling facility.

[Explanation of symbols]

1... γ-ray thickness meter, 2... Plate thickness measurement value signal of the γ-ray thickness meter, 3... Thickness gauge using a non-contact optical range meter, 4... Plate thickness of a thickness gauge using a non-contact optical range meter Measured value signal, 6...Thick steel plate, 7...Transfer position signal, 8...Transfer position detector, 10...Multi-point plate thickness calculation circuit, 11...Measured plate thickness value, 12...Hot rolled steel plate detector, 13...Transfer amount Detector, 15... Plate thickness control section, 16... Hydraulic rolling section, 17... Universal rolling mill, 18... Thick plate rolling line, 19... Control computer, 20... Plate thickness setting signal.

Claims (1)

[Claims] [Claim 1] When controlling the thickness of a thick plate by measuring the thickness of a thick plate during rolling, a gamma-ray thickness meter and a thickness meter using a non-contact optical distance meter are used. A method for measuring the thickness of a thick plate, characterized in that the measured value of the distance meter is corrected by the measured value of , and the plate thickness is determined from the corrected measured value.