JPH0740008A - Method for measuring thickness of thin cast slab in continuous casting - Google Patents

Abstract

PURPOSE:To simplify a measuring instrument and to reduce the cost by changing scannings in the width direction and the longitudinal direction at each constant time and executing a slab thickness measurement of a thin cast slab. CONSTITUTION:Molten metal is poured into gap between one pair of cooling rolls 1a, 1b and rapidly solidified to continuously produce the thin cast slab 2. An X-ray type slab thickness meter 3 is arranged in a travelling course in the thin cast slab 2 and scanns the slab thickness over the width direction of the cast slab 2 with a controller 4 and also, controlled so as to execute the slab thickness scanning in the longitudinal direction of the cast slab by stopping this meter to a fixed position in the width direction. The measured slab thickness data are inputted to a computing element 5 and the cooling rolls 1a, 1b are controlled so as to keep the suitable gap through a hydraulic cylinder 6. The scannings in the width direction and the longitudinal direction are changed at each constant time to execute the slab thickness measurement of the thin cast slab 2. By this method, the slab thickness meter needed in two sets can measure each point in only one set.

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 thickness of a thin cast piece manufactured by continuous casting, in which the thickness of the thin cast piece is measured in the width direction and the longitudinal direction.

[0002]

2. Description of the Related Art As a method of measuring and controlling a plate thickness in a continuous casting device such as a twin roll, for example, JP-A-60-64 is used.
No. 754 and Japanese Patent Application Laid-Open No. 60-83746 disclose that feedback control is performed based on the data obtained by measuring the plate thickness, and that these data are used to roughly correct the control.

[0003]

The plate thickness measurement data necessary for controlling the plate thickness of a cast piece cast by a continuous casting device such as a twin roll is usually obtained by a roll gap measured by a detector incorporated in the main body of the casting device. Is measured and the plate thickness is controlled based on this data.In this case, an error occurs in the measured value of the gap due to thermal expansion of the frame during casting, and as a result, the control amount of the gap is originally required. Unlike the quantity, the plate thickness error is increased more and more.

Therefore, the plate thickness data necessary for controlling the plate thickness for ensuring the accuracy is obtained by measuring the cast slab being cast online and comparing the target slab thickness with the thermal expansion. It is used after correcting the error.

As the control plate thickness measurement data, measurement data in the slab longitudinal direction at a representative point in the slab width direction, for example, the center, is used. Further, as the casting performance data, it is necessary to collect the sheet thickness distribution in the width direction of the slab, that is, the data such as the crown. Conventionally, since a method of continuously collecting these data is used, a plate thickness gauge dedicated to each of the width direction and the longitudinal direction is required, and therefore the facility becomes complicated and expensive. there were.

In view of the above-mentioned problems, the present invention provides a method for measuring the thickness of a thin cast slab that simplifies the equipment and reduces the cost by effectively measuring this with a single thickness gauge in continuous casting. provide.

[0007]

According to the present invention, when a molten metal is injected between a pair of cooling rolls and rapidly solidified to produce a thin-walled slab continuously, the thin-walled slab is provided with a traveling path. With the installed plate thickness gauge, after scanning the plate thickness in the width direction of the traveling thin-walled slab, stop the plate thickness meter at a specific position in the width direction of the thin-walled slab, and then perform plate thickness scanning in the longitudinal direction of the slab. A method for measuring the thickness of a thin cast slab by continuous casting is characterized in that the scanning of the width direction and the longitudinal direction is switched at regular intervals to measure the thickness of the thin cast slab. As the plate thickness measuring method, any of a radiation method, an optical method, a sound wave method, and a mechanical method can be adopted as long as there is no problem in heat resistance and measurement accuracy.

[0008]

In the conventional measurement and control of the plate thickness of a continuous thin cast slab, etc., the plate thickness is measured continuously, but this is dedicated to the collection of correction error data, for example, to measure the slab crown. , I needed another board thickness gauge. The present invention intermittently measures the plate thickness correction data, and enables another measurement, for example, the slab crown amount, while the correction data is not measured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of a plate thickness control system for thin cast pieces in continuous casting. A continuous casting apparatus injects molten metal between a pair of cooling rolls 1a and 1b and rapidly solidifies it. Then, thin cast pieces are continuously manufactured.

An X-ray type plate thickness gauge 3 is installed in the traveling path of the cast thin cast piece 2, and the plate thickness gauge 3 scans the plate thickness across the width of the cast piece 2 by the controller 4. At the same time, it is controlled to stop at a predetermined position in the width direction and perform plate thickness scanning in the longitudinal direction of the slab. The plate thickness data measured here is input to the calculator 5, and is controlled via the hydraulic cylinder 6 so that the cooling rolls 1a and 1b maintain an appropriate gap.

2 (a) to 2 (c) are drawings for explaining the plate thickness scanning procedure of the thin cast piece 2 cast by the plate thickness gauge 3, and FIG. 2 (a) is a longitudinal direction of the cast piece by the conventional method. An example of the plate thickness measurement result is shown. The roll gap is controlled so that the plate thickness is constant in the cooling rolls 1a and 1b, but conventionally, the plate thickness in the longitudinal direction is continuously measured and every 60 seconds. The deviation from the target plate thickness is evaluated and corrected by the average value.

In the measuring method of the present embodiment, as shown in FIG. 3B, the thickness of the slab in the longitudinal direction is actually measured, for example, half of that is 30.
It is performed for a second, and the deviation from the target value is evaluated and corrected every 60 seconds by the average value. Therefore, the above 30
During periods other than seconds, as shown in FIG. 7C, the plate thickness meter 3 scanning mode is switched to scan the plate thickness meter 3 in the width direction to measure the slab crown.

The interval for changing the scanning mode during measurement can be shortened as long as accuracy is allowed. The switching of the measurement timing may be performed by the casting length, in addition to the above-mentioned time. In addition to crown measurement, it is possible to collect multiple types of data, such as measuring the plate thickness at any point in the width direction of the slab.

FIG. 3 shows a cast width of 800 mm and a cast piece thickness of 3 m.
m thin-walled slab is cast at a casting speed of 60 mm / min,
An example of the scanning mode on the slab and the measurement result of the plate thickness when the plate thickness is measured by the measuring method of the present invention using the plate thickness meter 3 will be described below.

[0015] Fig. (A) shows an example in which the thickness of the slab in the width direction is measured at intervals of 30 seconds and the crown measurement is switched every 30 seconds, and (b) is the center of the slab width direction and the width direction. Arbitrary two points, 200 and 15 from the center in the case of this example
An example of execution when the plate thickness is measured at the position of 0 mm is shown.

As described above, the scanning of the plate thickness gauge is effectively switched at regular intervals to perform the measurement, so that the thickness of one piece can be measured by one plate thickness gauge without degrading the accuracy of the measurement data. And it becomes possible to perform crown measurement.

[0017]

As described above, according to the present invention, the plate thickness is scanned in the width direction of the traveling thin cast piece by one plate thickness gauge, and this is switched at regular intervals to change the plate thickness in the longitudinal direction of the cast piece. By performing scanning, and repeating this operation in sequence, and performing measurement of the plate thickness while separating the results, it becomes possible to measure each point with one plate thickness gauge, which required two units in the past. Can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a drawing showing an example of a plate thickness control system for thin cast pieces in continuous casting.

2A and 2B are drawings for explaining a scanning procedure of a thin cast piece cast by a plate thickness meter, FIG. 2A is an example of the result of measuring the thickness in the longitudinal direction of the cast piece by the conventional method, and FIG. An example of the thickness measurement result in the longitudinal direction of the example, (c) is a drawing showing an example of the scanning mode on the slab.

FIG. 3 shows an example of performing thin cast plate thickness measurement according to the present invention. FIG.
FIG. 6B is a drawing showing the scanning mode and plate thickness measurement results when measuring an arbitrary point in the central portion and the width direction. 1a, 1b Cooling roll 2 Cast thin cast piece 3 Plate thickness gauge 4 Controller 5 Computing unit 6 Hydraulic cylinder

Claims (1)

[Claims] 1. When a molten metal is injected between a pair of cooling rolls and rapidly solidified to produce thin-walled slabs continuously, a plate thickness gauge installed on a traveling path of the thin-walled slabs is used for running. After scanning the plate thickness in the width direction of the thin cast slab to be performed, stop the plate thickness meter at a specific position in the width direction of the thin slab and continuously perform plate thickness scanning in the longitudinal direction of the slab, A method for measuring the thickness of a thin cast slab by continuous casting, characterized in that scanning is switched at regular intervals to measure the thickness of the thin slab.