JPS5913518A - Measuring method of thickness of steel plate - Google Patents

Abstract

PURPOSE:To obtain the accurate plate thickness, by substituting the value of mass absorption coefficient (mum) of a material, determined by correction basing on the plate thickness estimated or measured by a rolling schedule or a permeated radiation dose, etc., into a theoretical formula. CONSTITUTION:The estimated plate thickness is obtained by a rolling schedule or a gauge-meter system, etc. Further, a permeated radiation dose obtained by a permeated radiation-dose detector 12 is substituted into a theoretical formula to measure the plate thickness. Then a mum value is determined by correction from said estimated or measured plate thickness. Next, the determined mum value is substituted into a theoretical formula, used for obtaining the plate thickness from a permeated radiation dose, to obtain the accurate plate thickness. Thus, an automatic plate-thickness controlling device is accurately controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for measuring the plate thickness using radiation during rolling of a steel plate, and calculates the predicted or measured plate thickness in μm for each measurement.
This invention relates to a method for quickly measuring a steel sheet in which the accurate sheet thickness is determined by correcting and determining the (mass absorption coefficient of the material) value and substituting it into a theoretical formula for calculating the sheet thickness from the amount of transmitted radiation.

In the rolling process, it is important to measure the thickness of the steel plate successively during rolling and feed it back to the rolling control mechanism for accuracy control. The quantitative method is widely used.

By the way, μm (mass absorption coefficient of material) in equation (2) is
Theoretically, it is treated as a constant value regardless of the thickness of the steel plate to be measured, but in actual operation, the degree of scattering of radiation differs depending on the thickness of the steel plate to be measured, and the actual path Due to differences in line height, etc., the relationship between plate thickness t and transmitted radiation dose t deviates from the theoretical value characteristics, as shown in Figure 2. For example, for the actual plate thickness t Substituting the transmitted radiation dose factor into the theoretical formula x'Ft to find the plate thickness yields the value tn, and the difference between it and the actual plate thickness tx is α.
This will result in an error of only

Therefore, in order to correct this, as shown in Figure 1, μm
It is necessary to use a value that changes depending on the thickness of the steel plate to be measured.

First, for example, in a bus during rolling, the final finished thickness t should be used, where the μm value μm1 corresponding to the actual plate thickness ζ at that bus should be used. K using the corresponding μm value μmO,
When measuring plate thickness, a large error will occur in the measured plate thickness.

Therefore, in order to accurately measure plate thickness, it is necessary to select an appropriate μm value that corresponds to the thickness of the steel plate to be measured.
Before starting the measurement, please use some method to predict the thickness of the steel plate to be measured, select an appropriate μm value, and check whether the predicted thickness shown on the left is approximately equal to the actual thickness. ,
Even while the measurement is continuing, it is necessary to verify it every moment, and if it is determined that the predicted plate thickness is incorrect, it is necessary to change the μm value to a more appropriate value and continue the measurement. The present invention provides a complete method for eliminating the conventional deficiencies in plate thickness prediction, etc. related to the selection of the 1+I μm value, as well as the occurrence of measurement plate thickness errors caused by these.

In particular, in the rolling process, in the rolling bus, it is possible to eliminate errors in measured plate thickness due to errors in predicted plate thickness.
Alternatively, it is possible to deal with the inability to measure the plate thickness due to the unpredictability of the plate thickness.

In addition to this, when measuring the thickness of a steel plate whose thickness changes significantly during the process (sometimes the thickness is intentionally changed in order to improve the final rolling accuracy), This eliminates the difficulty of predicting the thickness change point and determining the timing of changing the μm value, and enables accurate thickness measurement over the entire length of the steel plate.

The method of the present invention will be explained below based on the embodiments shown in the drawings.

FIG. 3 is a system diagram showing the entire apparatus to which the method of the present invention is applied. In the same figure, 1 is the rolling machine o2v2vi upper and lower work rolls, 3 is the upper and lower backup roll, 4 is the hydraulic cylinder IJ 7der, and 5 is the magnet for detecting the amount of oil column installed in the hydraulic cylinder 4. scale, 6
is a load cell that detects the rolling load P, a position detector that detects the positions of the 7Vi rolling screw, and the 8 Vis rolling screw 7. A rolling material (steel plate) 9 is caught between the work rolls 2 of the rolling mill 1 from the left side of the figure, is rolled, and exits to the right side. Place work roll 2.2 in the position immediately after unloading,
A radiation source 11 serving as a radiation thickness gauge 10 and a transmitted radiation dose detector 12 opposing the radiation source 11 are arranged with a steel plate 9 interposed therebetween.

Reference numeral 13 denotes a precision calculator that controls the rolling mill 1 and the radiation thickness gauge 10. The calculator 13 calculates the mass absorption coefficient μm of the steel plate 9 based on the predicted plate thickness of the tip of the steel plate obtained from the rolling schedule or the cage gauge meter method, or the measured plate thickness during rolling obtained from the radiation thickness gauge 10. A calculating unit 14 for determining and a transmitted radiation dose detector 12 of the radiation thickness meter 10
Signalman obtained from. a calculator 15 that calculates the current plate thickness from /It and the μm value obtained by the calculator 14;
has. The predicted plate thickness is calculated in the following manner using the calculator 14 for determining the μm value. That is, in the case of the gauge meter method, first, the roll opening degree S is determined by the calculator 16 from the signal a from the detector 8 that detects the position of the reduction screw 7 and the oil column amount signal from the Magnescale 5. Subsequently, a predicted plate thickness is calculated in a calculation unit 17 from the load signal P of the load cell 6 as the signal source. The arithmetic expression in this case is ty=80+-...il1 (Friendship M: Mill's constant). When using the rolling schedule, the plate thickness t2 for each pass is set in advance in the schedule setting section 18.

Next, a method of measuring the plate thickness within one pass using the apparatus according to the above configuration will be explained based on the flowchart shown in FIG.

Regarding the tip of the rolled steel plate 9, it is impossible to determine the μm value in advance using the plate thickness measurement value using the radiation thickness meter 10. Therefore, if the gauge meter value can be obtained, the predicted plate thickness can be determined. The μm value corresponding to ty or t2 is determined by the calculator 14 from the characteristic diagram shown in FIG. The μm value at this time is assumed to be μm2 in FIG. 4 for convenience of explanation. Next, the calculation unit 15 calculates the plate thickness based on the transmitted radiation dose tVc.

The calculation in the calculator 15 is based on the formula % formula %(2
) In equation (2), μm is replaced with the above μmz vc and Tk and tVc. When the predicted plate thickness s or t2 cannot be obtained due to a failure of the load cell 6, etc., the steel plate 9 is placed at the measuring position of the radiation thickness gauge 10 with the transmitted radiation ffIt
and the theoretical value μm are substituted into equation (2) to find the plate thickness t. In the case of Co, there is a delay of one step in being able to meaningfully measure the thickness of the plate compared to the case where the thickness can be predicted. On the other hand, the predicted plate thickness.

The plate thickness t2 was first determined by t2 and obtained by substituting the mass absorption coefficient μmz and the transmitted radiation material t into equation (2).
is compared with the predicted plate thickness ty or t/itZ, and if the difference is thicker than the value d indicating the capacity range, then ty or tz contains a large error for the predicted plate thickness. From the above t2VC (& If the thickness cannot be predicted, J1 new fc mass absorption coefficient μmsk correction is determined from the above tVc. Then, substitute this into equation (2) to calculate the plate thickness tx again. .In addition, if the difference between t2 and tg5 is within the valley range (d(!: equal or greater), then t! is the exact steep plate thickness, and the first These output signal values are sent to the rolling control section and become control factors for automatic plate thickness control (AGC).

On the other hand, when the thickness measurements of the steel plate 9 are performed continuously, the corrected specific mass absorption coefficient μm! or μ
ms, and the plate thickness TX is determined sequentially using the transmitted radiation element tVc (2) 2. Next, this Tx is also
1, 1. , 1. If the difference is greater than the value θ, then the μ used for measurement is
m value Vj, rarely judged as inappropriate, plate thickness T
Correct and determine the new mass absorption coefficient μm4 from x K0
Then, t,1 is obtained from the μm4 using equation (2). On the other hand, T
If the difference between x and X is equal to or smaller than θ, Tx
is an accurate value and will appear as is.

These output signal values are sent to the rolling control section and are used as control factors for automatic plate thickness control (AGC).

If the thickness measurement of the steel plate 9 is still being continued, the process returns to the block of the flowchart in which the plate thickness T'X is determined by the transmitted radiation material t during which the measurement is being continued, and this process is repeated. However, from the second time onwards, the plate thickness is calculated based on the corrected t mass absorption coefficient μm.

If it is not continuing, it is set as KijEND. The above is the method for measuring the plate thickness in one bus, and if a plurality of round trip buses are to be used, the above operation can be repeated.

As explained above], the method for failure 1 is to predict the plate thickness during rolling or add 6111, correct the μm value with h based on the plate thickness, and c! 1. Since the accurate plate thickness is obtained by substituting 'i into the theoretical formula, the obtained plate thickness is very accurate and is excellent for accuracy control such as automatic plate thickness control (AGO). Furthermore, even if the plate thickness changes midway, the system automatically determines the position of the plate thickness change and the timing for changing the μm value setting, providing excellent responsiveness.

[Brief explanation of the drawing]

Figure 1 is a drawing showing the relationship between plate thickness and mass absorption coefficient, Figure 2
The figure shows the relationship between plate thickness and transmitted radiation dose.
3 is a system diagram showing the entire apparatus to which the method of the present invention is applied, FIG. 4 is a flowchart of the apparatus 1, and FIG. 3 is a flow chart of the apparatus. 9... Steel plate 10... Radiation thickness meter patent applicant
Sumitomo Metal Industries Co., Ltd. Representative 3!11 Patent Attorney FiJ@Hiko Procedural Amendment Layer (Voluntary) August 6, 1972 2, Title of Invention Method for Measuring Thickness of Steel Plate 3 Relationship with the Amendment Person Case Patent applicant location: 5-15 Kitahama, Higashi-ku, Osaka Name:
(211) Representative of Sumitomo Metal Industries, Ltd.
Representative Director Nori Kumagai 4, Agent 5, Amendment required Voluntary amendment 6, Subject of amendment 7, Contents of amendment (1) ``Amendment of drawings attached to application'' ■ Figure 4 attached to the application Correct as shown.

Claims (1)

[Claims] 1. When measuring the plate thickness using radiation during rolling of a steel plate, the measured plate thickness determined by the theoretical formula from the predicted plate thickness or the amount of transmitted radiation determined by the rolling schedule or gauge meter method, etc. A method for measuring the thickness of an ore plate, characterized in that the accurate thickness of the steel plate is determined by correcting and determining the mass absorption coefficient of .