JPH02274353A - Method for supporting cast slab in continuous casting machine - Google Patents

Abstract

PURPOSE:To reduce a quantity of water consumption as far as possible and to keep the necessary supporting pressure by supplying fluid having viscosity higher than that of cooling water to outer edge part side of overlapping part of a cast slab in a cooling supporting plate. CONSTITUTION:The high viscosity fluid is supplied through a supplying passage 6 provided in a pressurizing port for high viscosity fluid arranged at the outer edge side of the cooling supporting plate 3 from the rear side. Then, the high viscosity fluid supplied to the pressurizing port 5 from this supplying passage 6 can prevent flowing-out of the cooling water supplied into a pressurizing port 4 arranged at center part of the cooling supporting plate 3. By using the high viscosity fluid as sealing fluid in such a way, the cooling water consumption can be drastically reduced. Further, the pressure in the pressurizing port can be kept high with a little quantity of the cooling water and the cast slab can be held without any bulging.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides continuous casting slabs drawn from a mold with cooling water supplied between the slabs and a cooling support plate disposed close to the slabs. This invention relates to an improvement in the method of supporting water pressure.

(Prior Art) The most common method for supporting a continuously cast slab pulled out from a mold is to support it by rollers 1, as shown in FIG.

However, in this method of supporting with rollers 1, since no pressure acts between rollers 1 and 1 (indicated by the arrow in the figure), the solidified shell 2A expands outward due to the static pressure of the molten steel of unsolidified molten tli42B. go. When this solidified shell 2A expands too much, a breakout occurs in which the solidified shell is broken and the unsolidified molten steel 2B inside flows out.

In addition, since the roller 1 becomes an obstacle when cooling the slab 2,
Another drawback is that there are restrictions on the location where the cooling water is sprayed.

On the other hand, as shown in Fig. 6, a method has also been devised in which cooling water is supplied from a cooling support plate 3 placed close to the slab 2, and the slab 2 is supported by the water pressure of this cooling water (in practice). Publication No. 61-31818).

According to this method, the drawbacks of the support method using rollers can be solved.

(Problems to be Solved by the Invention) However, even with the above-mentioned method of supporting the slab by the water pressure of the cooling water, the support pressure is difficult to increase because water with low viscosity is used to support the slab. There was also the problem of a large amount of cooling water flowing out. The present invention was made in view of the above problems, and it is possible to reduce the amount of water consumed as much as possible and to obtain the required supporting pressure. The purpose of the present invention is to provide a fluid support method.

(Means for Solving the Problem) The fluid support method is already known as a non-contact support method, and as shown in FIG. 2, the internal pressure P0 of the pressure boat 4 on the cooling support plate 3 is expressed by the following formula. Given.

P o P at = 12 μ Q l / h 3 where, PiL: atmospheric pressure, μ: fluid viscosity Q (= Vh1 outflow flow rate per unit length in the direction perpendicular to the paper surface h: cooling support plate 3 and slab 2 Clearance V between: Velocity of fluid flowing out from clearance h Therefore, in order to increase the internal pressure P without increasing the outflow flow ff1Q in the limited space 2, it is necessary to increase the viscosity of the fluid. I understand.

On the other hand, the clearance h cannot be made smaller than a certain value in order to prevent the cooling support plate 3 from coming into contact with the slab 2 and being worn out.

The present invention has been made based on the above idea, and supports a continuously cast slab drawn from a mold by a fluid supplied between the slab and a cooling support plate disposed close to the slab. In the method, the gist is to supply a fluid with a higher viscosity than the fluid to the outer edge side of the overlapping portion with the slab in the cooling support plate to reduce the flow rate of the fluid from the cooling support plate as much as possible. This is a method of supporting slabs in a continuous casting machine.

(Function) According to the method of the present invention described above, the outflow flow rate of the cooling fluid supplied inside the cooling support plate is suppressed as much as possible by the high viscosity fluid supplied to the outer edge side of the cooling support plate, and The internal pressure P0 within the pressure boat can also be maintained high.

(Example) The present invention will be explained below based on FIG. 1, FIG. 3, and FIG. 4.

FIG. 1 is a schematic diagram showing an embodiment of a slab support device for carrying out the method of the present invention.

In FIG. 1, reference numeral 5 denotes a pressure boat for high viscosity fluid provided on the outer edge side of the cooling support plate 3, and the high viscosity fluid Fluid is supplied. The high viscosity fluid supplied from this supply passage 6 to the pressure boat 5 plays a role in preventing the cooling water supplied to the pressure boat 4 provided at the center of the cooling support plate 3 from flowing out. be.

In FIG. 1, 7 is a high viscosity fluid discharge passage, 8 is a cooling water discharge passage, and 9 is a cooling water supply passage.

By the way, when rapeseed oil with a viscosity η of 90 cp at 30"C is used as the high viscosity fluid, the clearance h must be 0.6 in order to maintain the internal pressure P in the pressure port 4 0.6 atm higher than atmospheric pressure. ~0.'1 mm, it was sufficient to supply rapeseed oil at a flow rate of approximately 16 f/min (see Figure 3).In this case, the supply of cooling water (viscosity η at 30°C is 0.8 cp) Flow rate is 500i10
It was Iin.

On the other hand, in order to obtain the same internal pressure as described above with the same clearance h using only cooling water, it was necessary to supply approximately 15001/min (see Fig. 4).

By using a high viscosity fluid as a sealing fluid in this way, it is possible to significantly reduce the flow rate of cooling water used.

Note that, as the high viscosity fluid, it is of course possible to use silicone oil, rolling oil, etc. in addition to the above-mentioned rapeseed oil.

When slabs of the steel types shown in the table below were continuously cast under the same conditions as described above, the slabs could be supported well without bulging.

(Effects of the Invention) As explained above, according to the method of the present invention, the pressure inside the pressure boat can be maintained high with a small amount of cooling water, and the slab can be held without bulging.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the method of the present invention, Figure 2 is a conceptual diagram of fluid support, Figure 3 is a diagram of the relationship between flow rate and clearance when using high viscosity fluid, and Figure 4 is a diagram showing the relationship between flow rate and clearance when using water. Similar figures, FIGS. 5 and 6, are illustrations of conventional support methods. 3 is a cooling support plate, 4.5 is a pressure boat, 6.9 is a supply passage, and 7.8 is a discharge passage. Figure 1 Figure N3 Figure 6 Figure 2 Kutsarasis basket (m-)

Claims (1)

[Claims] (1) A method in which a continuously cast slab drawn from a mold is supported by fluid supplied between the slab and a cooling support plate disposed close to the slab, in which the continuous casting slab is A method for supporting a slab in a continuous casting machine, characterized in that a fluid having a higher viscosity than the above fluid is supplied to the outer edge side of the overlapping portion, and the flow rate of the fluid flowing out from the cooling support plate is reduced as much as possible.