JPS6376745A - Measuring instrument for powder layer thickness in continuous casting mold - Google Patents

Abstract

PURPOSE:To find powder layer thickness, to stabilize continuous casting operation and to improve the quality by reflecting laser beam toward horizontal direction by reflection mirror, which is horizontally shiftable on a mold and operating the detected height of the upper face of powder and the measured molten surface level. CONSTITUTION:The laser beam transmitting/receiving device 3, which is shifted on the horizontal plane by a shifting mechanism 6, is reflected on the powder 2 surface above the molten steel 8 in a mold 1 by the reflection mirror 4 at a tip of horizontal arm 5 and the height signal is transmitted to an arithmetic unit 9. On the other hand, the thickness of powder layer 2 is found as compared with the signal transmitted from the molten surface leveler 7, to record on a printer 11. And, feeding quantity of the powder is controller 12 and the thickness of powder 2 is always surely maintained. Further, by operating the shifting mechanism 6, an image 10 of the powder 2 surface in the mold 1 is observed, to stabilize the continuous casting operation and the quality of cast slab is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a technique for measuring the thickness of a powder layer in a continuous casting mold, and more specifically, it measures the upper surface level of powder in a mold using a laser beam, and measures the level of the powder layer in the mold. This invention relates to a device for measuring the powder layer thickness based on the difference from the scene level.

Technical Background In continuous casting of steel, powder casting is generally performed in which powdered or granular additives (commonly known as powder) are added to the surface of the molten steel in a mold to coat the surface of the molten steel. The role of this powder is: (1) to coat the surface of the molten steel and melt it, and to prevent air oxidation of the molten steel by blocking it from the atmosphere with the molten layer and the unmelted powder layer above it; (2)
The molten layer and the unmelted layer of the powder prevent heat dissipation and keep the molten surface warm; (1) Absorb non-metallic inclusions in the floating and separated molten steel and clean the molten steel; (2) The molten layer of the powder It flows between the mold and the slab while covering the surface of the molten steel, forming a coating ingot, thereby improving the surface properties of the slab.

In order for these powders to perform their roles satisfactorily, use high-quality powders that are appropriate for the casting temperature, and maintain the thickness of the powder layer in the mold uniformly to the thickness required by the casting conditions. It is necessary to supply powder in a similar manner. For this purpose, a means to accurately and quickly measure the powder layer thickness within the mold is required.

Prior art and its problems The powder layer thickness in a continuous casting mold can be determined from the difference between the powder level and the molten metal level.

Methods for measuring the powder level include: ■The television camera method (Japanese Patent Laid-Open No. 57-25270), in which a television camera takes a picture of the inside of the mold and processes the image to measure the powder level.
, ■ lf3 through a heat-resistant rod immersed in the mold.
Ultrasonic method that generates sound waves and measures the powder level from changes in the echo waveform (Japanese Patent Application Laid-open No. 57-56146>
,■Electrical method in which an electrode rod is immersed in a mold and the powder level is measured from the change in resistance between the electrodes (Japanese Patent Laid-Open No. 57
-109555) etc. are known.

However, as is well known, the space between the mold and Tandin 91 of a continuous casting machine is narrow, so the TV camera method has the disadvantage that the entire mold cannot be seen, and the ultrasonic method and electrode method have a fixed measurement position. There are problems with physical measurement due to placement, and the upper surface of the powder in the mold is not a uniform plane but has undulations, so there is the inconvenience that values measured locally are not representative of the whole. With either method, it was impossible to accurately measure the powder level within the mold over the entire area.

In addition to the above-mentioned method, there has been reported a method for measuring waste level using the method of (2) directly projecting a laser beam and measuring the distance from the reflected light. However, in the method of directly projecting a laser, there are obstacles such as a tray case on the optical axis, so it may not be possible to measure a plane or even measure a single point, so it lacks practicality.

Purpose of the Invention The present invention was made in order to solve the above-mentioned conventional problems, and proposes an apparatus that can accurately measure the powder layer thickness throughout the mold without being subject to space constraints. That is.

Means for Solving the Problems This invention uses the radar light method described in (3) in order to eliminate the drawbacks of the conventional powder level methods such as (1) television camera method, (2) ultrasonic method, (2) electrode method, and (3) laser light method. This project proposes a powder layer thickness measuring device that uses a laser beam that enters horizontally between the mold and the tundish and is refracted by a reflecting mirror to measure the top surface level of the powder inside the mold. a laser beam transmitter/receiver that is movable back and forth and horizontally on a horizontal plane with respect to the mold; a level meter for measuring the level of the molten steel in the mold; the laser beam transmitter/receiver and the level of the molten steel; The present invention is characterized in that it is comprised of a calculation device that calculates the powder layer thickness in the mold from the output signal of the calculation device, and an image projection device that converts the output signal of the calculation device into an image signal and displays the contour line. .

That is, the present invention is a means for measuring the powder level using a laser beam in a narrow space between a mold and a tundish, in which a laser beam from a laser beam transmitter/receiver is horizontally incident, and a reflecting mirror attached to the transmitter/receiver is used to measure the powder level. The laser beam is refracted vertically downward to irradiate the upper surface of the powder inside the mold, and the laser beam transmitter/receiver can be moved back and forth and left and right on a horizontal plane relative to the mold so that the laser beam can be irradiated over the entire mold. It is something. This means that laser light can be irradiated into the mold within a narrow space between the mold and the tundish, and the powder level can be measured during mold downtime.

In this invention, the difference between the value measured by the laser beam transmitter/receiver equipped with this reflecting mirror and the front/back/left/right movable chamber 4R and the value measured by the mold-like molten steel level meter is the powder layer thickness. A method is adopted in which the output signals from the laser beam transmitter/receiver and the surface level meter are input to a demonstration device such as a microcomputer to determine the powder layer thickness, making it possible to visually grasp the powder layer thickness roughly over the entire surface of the mold. In order to do this, an image projection device was used which converts the output signal of the arithmetic device into an image signal and displays it as a contour line. The reason why the powder layer thickness is expressed as a contour line is because, as described above, the upper surface of the powder in the mold is not a uniform plane but has undulations.

In that case, the contour lines may be displayed in different colors so that they can be understood more clearly.

DISCLOSURE OF THE INVENTION BASED ON THE DRAWINGS FIG. 1 is a schematic diagram showing the configuration of a preferred laser beam transmitting/receiving section of the present invention, and FIG. 2 is a schematic diagram showing the entire groove bottom of the device of the present invention.

In Figure 1, (1) is the mold, (2) is the powder, (
3) is a laser beam transmitter/receiver, (4) is a reflecting mirror, (5
) is the horizontal arm, and (6) is the front/rear/left/right moving machine groove of the laser beam transmitter/receiver. The moving mechanism (6) is attached to a threaded rod (6) on a lower table (ei) provided along the side wall of the mold (1).
-2) and a guide rod (6-3), and by rotating the threaded rod (6-2) with a Y-axis direction pulse motor (6-4), A moving immovable table (6-5) and the lower table (6-5)
The threaded rod (6-2) is attached to the upper table (6-6) which is provided integrally with the immovable table (6-5) at right angles to 1).
The threaded rod (6-7) and the guide rod (6-8) intersect at right angles to the guide rod (6-3), and the threaded rod (6-7) is connected to the X-axis direction pulse motor (6-9).
), which moves back and forth with respect to the mold (1), and a laser beam transmitter/receiver (3) is installed on the upper moving table. There is.

In addition, in Fig. 2, (7) is the molten steel in the mold (1) (
8) is a hot water level meter that measures the hot water level, and (9) is a calculation device (microcomputer) that calculates the powder layer thickness based on the output signals from the laser beam transmitter/receiver (3) and the hot water level meter (7). , (10) is an image projection device that converts the output signal from the arithmetic device (9) into an image signal and displays the powder layer thickness with contour lines. Incidentally, (11) indicates a printer that records the powder layer thickness, and (12) indicates a powder input amount control device.

Function In the above device, the laser beam irradiated horizontally from the laser beam transmitter/receiver (3) is refracted vertically downward by the reflection mirror (4) provided at the tip of the horizontal arm (5) and is reflected on the surface to be measured. The upper surface of a certain powder (2) is irradiated, and the reflected light is received by the laser beam transmitter/receiver (3) again via the reflection mirror (4), and the powder level is measured. ) is the arithmetic unit (9)
Xllll111 direction pulse motor (6-9) and Y
It is moved back and forth, left and right by a 4'l11 direction pulse motor (6-4), and the output signal at that time is input to the arithmetic unit (9). In the arithmetic unit (9), the laser beam transmitter/receiver (3
) and the powder level value entered from the hot water level meter (
Powder (
2) The layer thickness is determined. The signal (powder layer thickness) output from the calculation device (9) is input to the image projection device (10) and converted into an image signal, and the powder layer thickness of the mold (1) excluding the immersed nozzle portion is displayed as a contour line. displayed. Therefore,
By removing the submerged nozzle part in the mold (1), the powder layer thickness can be seen at a glance.At the same time, the measured powder layer thickness can be output to the printer (11) and recorded as data. Roughly, the powder input amount control device (12) can be controlled according to the measured powder layer thickness.

As described in detail, the device of this invention can accurately and quickly measure the thickness of the powder layer in the mold over a period of time without being subject to space constraints, thereby producing finer powder than ever before. Supply control becomes possible, and the thickness of the powder layer in the mold can be maintained uniformly at the thickness required as the η-forming conditions. In addition, by analyzing the measurement data, it is possible to control the pulling speed of the slab. Therefore, it is possible to satisfactorily perform the role of the powder described above, and to prevent breakage and surface defects of the slab. This greatly contributes to the prevention of this, and has a great effect on stabilizing continuous casting operations and improving quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a preferred laser beam transmitting/receiving section of the present invention, and FIG. 2 is a schematic diagram showing the bottom of the body groove of the device of the present invention. 1...Mold, 2...Powder, 3...Laser beam transmitter/receiver, 4...Reflecting mirror, 6...Moving coin) 1, 7... Clean level meter, 8... - Molten steel, 9... Arithmetic device, 10... Image projection device. Applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 2 42 Powder immersion LL control device

Claims (1)

[Claims] A laser beam is incident horizontally from between the mold and the tundish and is refracted by a reflecting mirror to measure the upper surface level of the powder in the mold, and it moves back and forth and left and right on the horizontal plane with respect to the mold. a level meter for measuring the level of the molten steel in the mold; and a calculation device for determining the thickness of the powder layer in the mold from the output signals of the laser beam transmitter and receiver and the level meter;
A continuous casting mold in-powder layer thickness measuring device comprising: an image projection device that converts the output signal of the arithmetic device into an image signal and displays the contour line.