JPH0698464B2 - Belt deformation prevention device for belt type continuous casting machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to prevention of thermal deformation of a water-cooled belt applied to a belt type continuous casting machine.

[Conventional technology]

The conventional belt type continuous casting machine will be described with reference to FIGS. 3 and 4. FIG. 3 is a side view thereof, and FIG. 4 is a sectional front view taken along the line IV-IV of FIG. As shown in FIGS. 3 and 4, in the conventional belt type continuous casting machine, a pair of water-cooled belts 3 arranged side by side with a gap corresponding to the thickness T of the slab 21 and this belt 3 are provided. Rolled bearing box 5 that can move up and down
And a drive pulley 2 supported by a fixed bearing box 6 and a side dam 4 fixedly slidably sandwiched between both belts 3 and the like. ing.

The water cooling belt 3 and the side dam 4 are provided with respective water cooling devices (not shown) so as to cool the heat of solidification absorbed from the molten metal 20. Tension pulley 1
A pulling device such as an air cylinder (not shown) is attached to the drive pulley 2 via a bearing box 5, and a drive device (not shown) is attached to the drive pulley 2.

By the drive device (not shown), both water cooling belts 3 are slid on the side dam 4 via the drive pulley 2 and rotated in the direction shown by the arrow to melt into the casting mold formed of the side dam 4 and the water cooling belt 3. Metal 20 is continuously supplied. The molten metal 20 is cooled and solidified by the water cooling belt 3 and the fixed side dam 4 which move downward at an appropriate speed in the drawing, and moves downward in the drawing at a speed almost equal to the rotation speed of the water cooling belt 3 by an arrow. The slab 21 is sent to the next step discharged. In the figure, 20a represents the surface of the bath (meniscus).

[Problems to be solved by the invention]

In the process of casting a plate-shaped slab as described above,
The water cooling belt 3 is heated by heat transfer from the molten metal 20 and thermally expands in the longitudinal direction and the width direction. Conventionally, a means for absorbing thermal expansion in the longitudinal direction by applying an appropriate tension to the water-cooled belt 3 via the bearing box 5 and the tension pulley 1 has been taken. Since the distribution, that is, the amount of thermal expansion is not uniform, the vicinity of the center of the belt is deformed in an arc shape or a wave shape. Such deformation of the water cooling belt 3 also adversely affects the shape of the slab 21 formed between the water cooling belts 3 and appears as unevenness or double skin of the slab and only deteriorates the quality of the slab. Not only that, when this deformation becomes remarkable, a part of the solidified shell is broken, and the molten metal 20 inside may flow out, which makes stable operation impossible.

[Object of the Invention]

The present invention is intended to provide the same device that can eliminate the influence on the slab due to the deformation of the belt in the conventional belt type continuous casting machine described above.

[Inventors' findings]

The present inventors have found that the deformation of the water-cooled belt occurs due to the temperature distribution in the width direction of the belt, that is, due to the difference in thermal expansion. We paid attention to the fact that it is caused by the difference in heat transfer amount (heat absorption amount) at the edge. That is, this point will be described with reference to FIG. 2, which is a schematic diagram of the temperature distribution of the water cooling belt during the continuous casting operation. Note that FIG. 2 (a) is a view corresponding to FIG. 3, and FIG. 2 (b) is a temperature of each part (a, b, c, d and e) of the water cooling belt 3 of FIG. 2 (a). FIG. 2 (c) is an enlarged perspective view of the water-cooling belt of the α part in FIG. 2 (e), showing a distribution chart.

As shown in FIG. 2, the water-cooling belt 3 that has rotated the tension pulley 1 has a molten metal surface 20 (meniscus) 20a.
When it reaches near, it absorbs heat from the molten metal 20 and suddenly rises in temperature, and the temperature reaches 400 to 500 ° C. in the central part of the water cooling belt 3 which is in contact with the molten metal 20 as shown in FIG. , The amount of heat absorbed by the water-cooled belt 3 that descends together with the solidified slab gradually decreases as the surface temperature of the slab 21 decreases,
Along with this, the temperature of the water cooling belt 3 also gradually decreases.

At this time, the edges of both ends of the water-cooled belt 3 are molten metal 20 and cast slab.
Does not heat up because it does not contact 21. Here, a temperature distribution is generated in the width direction of the water cooling belt 3 at the abutting portion of the molten metal 20 and the cast slab 21 that are heated and both end portions that are not heated. This temperature distribution means a thermal expansion distribution, and the length differs between the central portion and both end portions, and this difference in length is due to the wavy deformation β of the water cooling belt as shown in FIG. 2 (c). It will be expressed as

[Means for solving problems]

Based on the above knowledge, the present invention has confirmed that the defects of the prior art can be prevented by heating the both end portions of the belt which are not heated, and has completed the present invention.

That is, the present invention supplies molten metal between a pair of water cooling belts arranged in parallel with each other and rotating in opposite directions,
In a belt-type continuous casting machine that continuously draws a slab that has been solidified into a plate shape, the electrodes that are in contact with the widthwise end edges of the pair of water cooling belts are attached, and the water cooling is performed by energizing the electrodes. A belt deformation preventing device for a belt type continuous casting machine, characterized in that both end edges of the belt are resistance-heated.

According to the present invention, an electrode is brought into contact with both end portions of the belt which are not heated, an appropriate voltage is applied to the electrode, and heating is performed by resistance heat generation of the water-cooled belt itself to make the widthwise temperature of the horizontal belt uniform.

At this time, the side dam is made of a copper block having a smaller electric resistance than the water cooling belt, and an electrical circuit that connects both edges of the water cooling belt and the side dam is formed between both electrodes, so that the central part of the water cooling belt does not generate heat. Should be.

〔Example〕

 An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a conceptual diagram of a water-cooling belt deformation prevention device according to an embodiment of the present invention. The water cooling belt 3 holds the slab 21 as well as the side dam 4. The side dam 4 is supported by the rear guide beam 7, and the width of the slab is determined by this supporting position. Although the side dam 4 is shown as moving in synchronization with the slab 21, it may be fixed.

A pair of electrodes 10 are attached to both edges of the water cooling belt 3. Of course, the electrode 10 preferably has a low electric resistance, and in this example, it is made of a copper plate and further backed up by a spring steel plate 11 having a spring force. Further, the back surface of the water cooling belt 3 is supported by the insulating guide roll 12.

By applying an appropriate voltage from the power source 15 to the electrodes 10 and 10, a current flows from the edge of the water cooling belt 3 toward the center.

Here, if the material of the side dam 4 is made of a material having a low electric resistance such as copper, the current passing through the water cooling belt 3 energizes the side dam 4 without flowing through the slab having a large electric resistance, and the other water cooling belt The other electrode through the edge of 3
Up to 10. That is, an electric circuit of a water cooling belt and a side dam as shown by an arrow in the figure is formed between both electrodes. Due to the current at this time, only both end portions of the water cooling belt 3 generate resistance heat, and the temperature distribution of the water cooling belt 3 is made uniform.

By making the temperature distribution uniform in this way, the deformation of the water cooling belt 3 can be prevented.

〔The invention's effect〕

Both ends of the water-cooling belt contact the electrodes, and a proper voltage is applied between the electrodes to partially heat only the both ends of the water-cooling belt to prevent thermal deformation of the water-cooling belt. As a result, (1) It is possible to manufacture a high quality slab without unevenness or double skin on the surface of the slab.

(2) It is possible to prevent a molten metal outflow accident (breakout) due to breakage of the solidified shell, and improve productivity.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an electric heating device for an edge portion of a water cooling belt according to an embodiment of the present invention. FIG. 2 is a schematic view of temperature distribution of a general water-cooled belt, FIG. 3 is a side view of a conventional belt type continuous casting machine, and FIG. 4 is a front view of IV-IV cross section of FIG.

Claims (1)

[Claims] 1. A belt-type continuous casting machine in which molten metal is supplied between a pair of water-cooling belts arranged in parallel with each other and rotating in opposite directions to continuously draw out slabs solidified in a plate shape, Electrodes that are in contact with the widthwise end edges of the pair of water-cooled belts are mounted, and the belt-shaped continuous type is characterized in that both edges of the water-cooled belts are resistance-heated by energizing between the electrodes. Belt deformation prevention device for casting machine.