JPH04266454A - Drawing-out control system in horizontal continuous casting device - Google Patents

Abstract

PURPOSE:To sufficiently prevent the leakage of a molten metal to the outer part of a mold at the time of developing breakout and to shorten the length of a mold tube in a mold divided in a casting direction. CONSTITUTION:A thermocouple 8 is provided on the outlet end part of the mold tube 3 and the mold is constituted by executing drawing control so as to tentatively stop the drawing-out or change the drawing speed to low speed in the case the detected temp. becomes the prescribed value or higher and controles drawing so as to be restored to an original condition.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is a drawing control system for horizontal continuous casting equipment that continuously casts long slabs by intermittently pulling bar-shaped slabs with square or round cross-sections. It is related to.

0002

[Prior Art] In this type of horizontal continuous casting equipment, during the initial solidification stage in the mold, the solidifying shell breaks, a so-called breakout, which causes the molten metal to leak out and destroy the mold. There is a possibility of melting and damage. As a method for preventing such breakout and leakage of molten metal, a method as disclosed in Japanese Patent Publication No. 49-26812 is known.

[0003] The method disclosed in the above publication involves providing a thermocouple in the mold tube corresponding to the back of the break ring provided at the inlet end of the mold, and detecting the temperature of the mold tube to determine the solidification state within the mold. This is a method to prevent breakouts and leakage of molten metal by monitoring and controlling withdrawal when an abnormality occurs.

0004

[Problems to be Solved by the Invention] However, although the above-mentioned conventional technology detects breakout at the inlet of the mold tube and prevents leakage of molten metal at that location, Breakouts such as vertical cracks at the center or rear end of the mold cannot be detected, and accurate control such as stopping the withdrawal before molten metal leaks cannot be performed, making the mold prone to melting and damage. In addition, in the case of adjustable molds that are used to make the cooling effect uniform within the mold, it is desirable to shorten the mold tube in order to improve the cross-sectional shape of the slab. The more you use it, the more molten metal will leak out. In addition to this adjustable mold, we also have a water-cooled mold tube and a water-cooled mold lined with a graphite liner to change the cooling capacity in the casting direction of the mold, such as the mold seen in Japanese Patent Publication No. 49-26812. Even in a mold in which these are combined, if the mold tube is shortened, more molten steel will leak out.

The present invention was made in view of the above-mentioned circumstances, and provides a drawing control system for horizontal continuous casting equipment that can sufficiently prevent leakage of molten metal during breakout and also allows the use of short mold tubes. The purpose is to provide.

[0006]

[Means for Solving the Problems] In order to achieve the above object, a drawing control system for horizontal continuous casting equipment according to the present invention includes a thermoelectric generator installed at the outlet end of a mold tube of a mold divided in the casting direction. When the temperature detected by the thermocouple and this thermocouple exceeds a predetermined value, the drawing is temporarily stopped or the drawing speed is changed to a low speed, and when the temperature detected above returns to the normal value, the drawing is returned to its original state. The control unit also includes a control unit for returning to the original state.

[0007]

[Operation] According to this invention, the temperature of the mold tube during operation is monitored by a thermocouple, and if the temperature of the mold tube exceeds a predetermined value when a breakout occurs near the outlet end of the mold tube. By temporarily stopping the drawing or reducing the drawing speed, it is possible to cool and solidify the molten metal that has partially flowed into the mold tube, thereby preventing it from leaking to the outside. In addition, with the above-mentioned cooling of the partially discharged molten metal,
When the temperature sensed by the thermocouple returns to its normal value, the withdrawal is restored to its original state.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a drawing control system for horizontal continuous casting equipment using an adjustable mold according to an embodiment of the present invention. In the figure, 1 is a tundish that holds the molten metal Y. 2 is the opening/closing gate,
The housing 2A is the tapping part 1 of the dan dish 1.
It is attached to the outer surface of A and includes a sliding gate 2B and a feed nozzle 2C. 3 is a fixed molded tube that serves as a strong cooling section, and has a cross-sectional shape that is almost the same as that of the slab, and the back surface of the Be-C tube is water-cooled.
It is composed of a U-tube, and a ceramic break ring 4 smaller than the inner diameter of the mold tube 3 is fitted into the inlet end of the mold tube 3. Reference numeral 5 designates an adjustable mold, which is lined with carbon with good lubricity and is divided into a plurality of parts in the circumferential direction and configured as a gentle cooling part that can be moved in the radial direction. 6 is a pinch roll,
It is driven and rotated by a drive motor 7 to intermittently pull out and move the slab 17 in the direction of arrow x. 14 is a molded casing.

Reference numeral 8 denotes a first thermocouple provided at the outlet end of the mold tube 3. A plurality of thermocouples 8 are arranged at intervals in the circumferential direction of the mold tube 3.
monitor and detect the temperature of 9 is the above mold tube 3
A second
These thermocouples are used to monitor the initial solidification state at the back of the break ring 4 in the mold tube 3 by temperature, and a plurality of thermocouples are arranged at intervals in the circumferential direction. 1
0 is a temperature/voltage converter which inputs the temperature signals detected by the first and second thermocouples 8 and 9, converts it into a voltage value, and outputs it. A computing unit 11 receives the output from the temperature/voltage converter 10, performs calculations as a function of time such as the initial solidification stage and the normal drawing operation stage, and outputs a control signal. Reference numeral 12 denotes a control unit for the pinch roll drive motor 7, which controls the rotation of the drive motor 7 and the pinch roll 6 based on the control signal output from the arithmetic unit 11.
2 and the arithmetic unit 11 constitute a drawing control section 13 for the slab 17.

[0011] Next, the drawing control operation by the drawing control system of the horizontal continuous casting equipment having the above configuration will be explained. First, the drawing starts when the molten metal Y in the dan dish 1 flows into the mold tube 3 and the second thermocouple 9 detects a temperature rise, based on a pre-programmed drawing pattern as shown in FIG. Like, dummy bar 1
Start with the pull-out movement in step 4. At this time, a protrusion guide 14A is provided at the rear end of the dummy bar 14 to deflect the molten metal flowing into the mold tube 3 toward the peripheral wall of the mold tube 3, as shown by arrow a, so that the initial solidification is prevented. To compensate for thermal shrinkage during heating and to ensure sufficient adhesion between the dummy bar 14 and the slab 17. Further, the second thermocouple 9 accurately monitors the solidification status at the solidification start portion. When the auto-start drawing pattern described above is completed, the drawing pattern automatically shifts to the normal drawing pattern.

[0012] When the drawing operation in the normal drawing pattern is normal, solidification starts at the back of the break ring 4 as shown in FIG. The second
The temperature detected by the thermocouple 9 is almost constant as shown in FIG. Then, due to sticking or poor welding between the shell C and the inner wall of the mold tube 3 at the solidification start point, the shell C breaks and breaks out B as shown in FIG. When O is generated, the temperature detected by the second thermocouple 9 changes greatly as shown in FIG. The drawing control section 13 operates based on this large temperature change, and reduces the drawing speed of the slab 17. The amount by which the drawing speed is reduced is set to a value that allows the solidified shell C to be thick enough to withstand the drawing resistance force, thereby preventing molten metal from leaking in the event of a breakout. can. When the normal coagulation condition is restored through the above-described drawing control, the normal drawing pattern is automatically restored.

Furthermore, during normal drawing operations, the temperature at the outlet end of the mold tube 3 is constantly monitored by the first thermocouple 8, and solidification at the downstream side of the break ring 4 inside the mold tube 3 is monitored at all times. If a breakout occurs due to rupture of the shell, the first thermocouple 8
The detected temperature increases rapidly. When the detected temperature exceeds a predetermined value, the rotational speeds of the drive motor 7 and the pinch roller 6 are controlled via the extraction control section 13 consisting of the arithmetic unit 11 and the control unit 12. Specifically, the drawing is temporarily stopped or the drawing speed is changed to a low speed, and the molten metal that has partially flowed into the mold tube 3 is cooled and solidified within the mold tube 3. Thereby, it is possible to prevent the partially leaked molten metal from leaking out of the mold tube 3, and it is also possible to suppress melting damage of the mold tube 3 itself as much as possible. Then, when the temperature detected by the first thermocouple 8 falls below a predetermined value, that is, returns to the value at the time of normal extraction, the original extraction state is automatically restored.

In the above embodiment, second and first thermocouples 9 and 8 are provided at the back of the break ring 4 provided at the inlet end of the mold tube 3 and at the outlet end of the mold tube 3, respectively. Both thermocouples 9, 8
We have described a system that can effectively prevent leakage of molten metal in the event of a breakout by combining withdrawal control based on the temperature detected by the thermocouple 8. Good too. Further, if a thermocouple is provided at each outlet end of the adjustable mold 5, and the temperature signals detected by the plurality of thermocouples are collectively processed to perform drawing control, more accurate control can be achieved. can be carried out. Further, in the above embodiments, the application was applied to a normal open adjustable mold, but it can also be applied to a closed adjustable mold equipped with a closed casing (not shown) that hermetically surrounds almost the entire area of the mold. This makes it even more effective.

[0015]

[Effects of the Invention] As described above, according to the present invention, the pullout is controlled by detecting breakouts such as vertical cracks and deformation in slabs with a rectangular cross section, which occur near the exit end of the mold tube. By doing so, it is possible to sufficiently prevent the molten metal that has partially flowed out due to the breakout from leaking to the outside, and by monitoring and controlling the solidification status at the outlet end of the mold tube 3, the cross-sectional shape can be made uniform. It is possible to cast slabs with good quality. In addition, since the leakage of molten metal can be prevented by drawing control, it is also possible to shorten the length of the mold tube of the mold that is divided in the casting direction, and from this aspect as well, the cross-sectional shape of the slab can be improved. can.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a drawing control system for horizontal continuous casting equipment using an adjustable mold according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of main parts showing the situation at the start of drawing.

FIG. 3 is a sectional view of main parts for explaining a normal pulling out situation.

FIG. 4 is a characteristic diagram of the temperature detected by the thermocouple in FIG. 3;

FIG. 5 is a sectional view of main parts for explaining the situation at the time of breakout.

FIG. 6 is a characteristic diagram of the temperature detected by the thermocouple in FIG. 5;

[Explanation of symbols]

1 Tundish 3 Mold tube 6 Pinch roll 7 Drive motor 8 First thermocouple 13 Pulling out control section

Claims (1)

[Claims] 1. A pull-out control system for horizontal continuous casting equipment in which a tundish and a mold tube of a mold divided in the casting direction are hermetically joined, the drawing control system comprising a thermocouple provided at the outlet end of the mold tube. When the temperature detected by this thermocouple exceeds a predetermined value, the drawing is temporarily stopped or the drawing speed is changed to a low speed,
A pultrusion control system for horizontal continuous casting equipment, further comprising a control unit that returns the pultrusion to its original state when the detected temperature returns to a normal value.