JPH01254351A - Cooling pad for belt type continuous casting machine - Google Patents

Abstract

PURPOSE:To maintain water film thickness to constant and to cast a cast slab having flat surface by arranging means, which automatically changes cooling water flowing area of each water supplying hole corresponding to variation of the water film thickness, in cooling water supplying/draining mechanism for cooling pad in belt type continuous casting machine. CONSTITUTION:Plural reverse tapered water supplying holes 4 are arranged in the cooling pad member 3 along width direction of the belt mold 1. Then, bar bodies 5 providing the tapered head part 6 are arranged to each water supplying hole 4. Each bar body 5 is fitted as slidable to wall 8 of header 7 and always pushed toward the water supplying hole 4 with a spring 10. The head part 6 supports as floating the belt mold 1 with action of the spring 10 and develops the water film flowing passage 11 between the belt mold 1 and the cooling pad member 3. The head part 6a receiving much force from molten metal 2 is pulled in at large distance and the head part 6b receiving less force is pulled in at small distance. Further, the head part 6c receiving no pressure of the molten metal is abutted on the water supplying hole 4. Therefore, the thickness of the water film flow passage 11, that is, the water film thickness is maintained to the constant and the belt mold 1 is always adjusted flat.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling pad for a belt-type continuous casting machine, and particularly relates to a cooling water supply/drainage mechanism suitable for flattening the surface of a slab to be cast. The invention relates to a cooling pad provided with a cooling pad.

[Conventional technology]

In the conventional cooling pad for a belt-type continuous casting machine using a hydrostatic pressure bearing pad, the cooling water supply and discharge mechanism is arranged in the belt mold and connected to a common header, as described in Japanese Patent Application Laid-Open No. 61-37355. It consisted of a plurality of water supply holes of different diameters and a plurality of drainage holes of different diameters.

[Problem to be solved by the invention]

In a belt-type continuous casting machine using a hydrostatic pressure bearing pad, the static pressure load of molten metal that the belt mold receives is generated between the belt mold and the cooling pad by the cooling water supply and discharge mechanism for cooling the belt mold. It is suspended and supported by a hydrostatic bearing made of a water film. In order to flatten the surface of the slab cast in this type of belt-type continuous casting machine, it is necessary to keep the thickness of the water film between the belt mold and the cooling pad constant with respect to the belt mold. becomes.

The basic characteristic of hydrostatic bearings is the floating amount of the belt mold.

In other words, in areas where the distance between the surfaces of the belt mold, cooling pad, and
The cooling water pressure becomes lower than the static load pressure of the molten metal, reducing the floating height, and conversely, in areas where the floating height is small, the flow resistance increases and the cooling water pressure becomes higher than the static loading pressure. This characteristic is established under the condition that the amount of water supplied is constant or almost constant regardless of changes in water flow resistance.

By the way, in the above-mentioned conventional cooling pad, the multiple water supply holes arranged in the mold of the belt mold and connected to a common head are made to have different diameters by narrowing the cross-sectional area or providing a cap, so that the water supply holes can be made to have different diameters without regard to fluctuations in the water film. By providing sufficient resistance to the water supply hole, the above-mentioned condition of constant water supply amount was established. However, the resistance in this case causes a pressure loss, that is, an energy loss, in the cooling water supply pump, which poses a problem in economic efficiency during operation.

What is the above-mentioned change in the floating amount, that is, the water film thickness?

Most of this is caused by thermal deformation of the belt mold, and thermal deformation in the longitudinal direction can be prevented by applying tension in the longitudinal direction to the belt mold, but thermal deformation in the lateral direction of the belt mold is quite difficult to prevent.

There was a need to further strengthen the functionality of hydrostatic bearings.6 The purpose of the present invention is to overcome the drawbacks of the above-mentioned prior art and to improve the functionality of hydrostatic bearings without significant energy loss. The purpose is to provide a cooling pad for a belt-type continuous casting machine that can be used.

[Means to solve the problem]

The above object is achieved by providing the cooling water supply/discharge mechanism with means for automatically changing the cooling water flow area of each water supply hole in response to changes in the thickness of the water film.

[Effect]

Generally, the total resistance of the water supply part of the cooling pad is ΔpH1+
ΔP′1fl (ΔPin is the resistance of the water supply hole.

(8P'in is the resistance of the part exiting from the water supply hole to the water film part), and by making the former resistance ΔPin, which is unrelated to the water film thickness δ, sufficiently larger than the latter resistance ΔP'in, which is a function of δ. , with the total amount of water supplied from the water supply header being constant, the conditions for constant water supply at each water supply section are obtained, and under this condition, based on the water pressure (=0) discharged from the drain hole,
ΔPout+ΔP'out+ΔP, (ΔPout is the resistance of the drainage hole.

The cooling water pressure given by ΔP'out is the resistance at the part where the water enters the drainage hole from the water film, and 8P1 is the resistance of the water film thickness, is balanced with the load pressure of the belt mold. The water film thickness δ is the latter two of ΔP that conditions the cooling water pressure, that is, ΔP'ou
It is determined because t and ΔPw are functions of δ.

The above structure of the present invention further improves the condition of the above-mentioned prior art where the water supply amount is constant in response to changes in the water film thickness δ, and reduces the water supply amount in areas where the water film thickness δ is large. The amount of water supplied is increased in areas where the water film thickness is small, thereby further increasing the pressure difference between the cooling water pressure in areas where the water film thickness is large and the cooling water pressure in areas where the water film thickness is small. Maintains constant membrane thickness and improves hydrostatic bearing function.

〔Example〕

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

FIG. 1 shows a part of the cooling pad of the present invention, in which the belt mold 1 is deformed by the static pressure load of the molten metal 2. It has a plurality of tapered water supply holes 4 provided at 3,
A rod-shaped body 5 is provided corresponding to each water supply hole 4, each rod-shaped body 5 is provided with a tapered head 6 complementary to the corresponding water supply hole 4, and each head 6 cooperates with the corresponding water supply hole 4. . Each rod-shaped body 5 is slidably attached to the wall 8 of the header 7 by, for example, a bearing 9, and is always biased toward the water supply hole 4 by a spring 10 provided between the pad member 3 and the header wall 9. The head 6 of the rod-shaped body 5 comes into contact with the belt mold 1 under the action of the spring 10 to float and support the belt mold, thereby creating a water film channel 11 between the bell 1-mold 1 and the cooling pad member 3. .

Belt mold 1 deformed by static pressure load of molten metal 2
The force exerted on each head 6 of the rod-shaped body 5 is different, and the flow area (cross-sectional area) of the water supply hole 4 regulated by the head 6 also changes accordingly. In detail, the head 6a, which has been subjected to a large force, resists the force of the spring 10 and retracts by a large amount corresponding to the large force, and the water supply defined between the head and the water supply hole 4 is The flow area of the hole is made large, and on the other hand, the head part, for example 6b, which is subjected to a small force, is retracted by a small amount corresponding to that force, and the flow area is made small.
For example, the head 6C, which does not come into contact with the molten metal and does not receive any static pressure load pressure from the molten metal, completely seats on the taper part of the corresponding water supply hole 4, making the flow area zero and cutting off the water supply from that water supply hole. . Depending on the size of the flow area of the water supply hole 4, the amount of water flowing out from the water supply hole to the water film channel 11 changes, and therefore the pressure due to the water supply also changes in size. Therefore, the large water supply pressure from the water supply hole with a large circulation area strongly pushes back the belt mold part corresponding to this water supply hole, and as a result, the corresponding head is pushed back toward the water supply hole by the spring 10. This reduces the circulation area and water supply pressure. For water supply holes with small flow path area and low water supply pressure, the corresponding head is Bell +
- It is further drawn in by the A5 type to increase the distribution area. As described above, the flow area of each water supply hole 4 is automatically increased or decreased by each head 6 in contact with the belt mold 1 and the spring 1o to adjust the water supply pressure from each water supply hole.

The deformation of the belt mold 1 is corrected, thus keeping the thickness of the water film channel 11, ie, the water film J'J, constant. Therefore, the belt mold 1 is always adjusted and maintained flat, and a slab having a flat surface can be cast.

2a and 2b show a water supply hole portion according to another embodiment of the invention. In the embodiment of FIG. 2a, the water supply hole is cylindrical and the head 6 is tapered. In this embodiment, the flow area is defined between the lower edge of the cylindrical water supply hole and the tapered circumferential surface of the head 6, and the flow area can be adjusted by layer sensitivity. Alternatively, as shown in the figure, the rod-shaped body may be omitted and the head 6 may be biased directly by the spring 10.

In the embodiment of FIG. 2b, both the water supply hole 4 and the head 6 are substantially cylindrical, and a circular flange 12 is provided at the lower end of the head 6, and a flow area is formed between this flange and the lower surface of the water supply hole 4. Adjust. In addition, it is preferable to provide a water hole 13 in the rod-shaped body 5 that leads from the header 7 to the tip of the head 6 to prevent wear caused by direct contact between the head 6 and the belt mold 1. In this case, the head and the belt mold 1 Although they do not come in complete contact, the above-mentioned function of maintaining a constant water film thickness is fully fulfilled.

FIG. 3 shows yet another embodiment of the present invention. In each of the embodiments described above, the spring 10 was located inside the water supply ladder 7, but from the viewpoint of rust prevention, It is better to install the spring outside the header.

In the embodiment shown in FIG. 3, a bracket 14 is fixed to the outside of the wall 8 of the header 7, and a spring 10 is arranged between the rod-shaped body 5 and the bracket 14.

Further, in this embodiment, a plurality of rows of water supply holes 4 are connected to a common ladder 7 in the nursery direction, and drainage holes 15 are provided between the water supply holes. As mentioned above, the header pressure is given by the sum of the load of the belt mold 1 and the pressure loss of the water supply part, so if the header is made common to all the water supply holes in the casting direction, in the conventional technology described above, In order to supply the same amount of cooling water from each water supply hole, sufficient resistance, ie, a restriction, was provided in the water supply section so that the increase in molten metal could be ignored.

However, in this case, the pressure on the header increases,
The structural strength of the cooling pad was an issue.

In the embodiment shown in Fig. 3, the diameter of the water supply hole is made larger with respect to the casting direction, and this configuration reduces the pressure loss on the upstream side in the casting direction and increases the static pressure load pressure of the molten metal. Since it can respond to changes in the water film thickness δ, the header pressure can be reduced, making the cooling pad lighter, and the overall structure also allows for the centralization of intermediate piping for cooling water. It can also be simplified.

In the above embodiment, the amount of cooling water from each water supply hole is automatically controlled in response to changes in the water film thickness, and the water film thickness can be adjusted and maintained at a constant level, thereby correcting the deformation of the belt mold. The ability to do this has significantly improved.

It is possible to cast slabs with extremely high precision flat surfaces.
It was found that the accuracy of the slab thickness could be kept within ±Q, 3 mm.

In addition, the water supply resistance Δ in the cooling pad of the prior art described above
P is ΔP=ΔP(fo(d))+ΔP(go(δ)), where d is the water supply hole.
...■, while in the above embodiment of the present invention, the water supply resistance ΔP is.

8P=ΔP(gl(δ))+ΔP(fz(d))+ΔP
(gz(δ))...Represented by ■.

In the latter equation ■, the first term on the right side is a function that increases as the water film thickness δ increases, and the third term on the right side, which has the same size, is a function that decreases as δ increases, so overall the variation in the water film thickness δ It is possible to obtain a water supply resistance ΔP that is less affected by

Therefore, P(fo(d)) to the resistance of the first term on the right-hand side in the above-mentioned 2 according to the prior art is practically 2 from the aperture effect.
kg/cm" or more, but in the embodiment of the present invention, it is possible to make the resistance ΔP (fo(d)) of the second term on the right side of 20 as small as possible, and the total resistance is about 1 to 1 .5k
g/am” pressure loss can be reduced.

〔Effect of the invention〕

As is clear from the above, in the cooling pad of the present invention, the cooling water flow area of each water supply hole is automatically changed in response to changes in the water film thickness, and the water film thickness is adjusted and maintained constant. It improves the hydrostatic bearing function with energy loss, corrects the deformation of the belt mold and flattens it, allowing casting of slabs with flat surfaces.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mold of a cooling pad of a belt-type continuous casting machine according to an embodiment of the present invention, and FIGS. 2a and 2b are sectional views showing a part of a cooling pad of another embodiment of the present invention. ,
FIG. 3 is a longitudinal sectional view of a cooling pad according to yet another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Belt mold, 2... Molten metal, 4... Water supply hole, 6... Head, 11... Water film channel, 15... Drain hole.

Claims (1)

[Claims] 1. For cooling and supporting the belt mold by forming a water film of cooling water on the back surface of the belt mold that constitutes the mold of a belt-type continuous casting machine and supports molten metal for casting on the surface. In a cooling pad equipped with a cooling water supply/discharge mechanism having a plurality of cooling water supply holes and a plurality of drainage holes, the cooling water supply/discharge mechanism is configured to supply cooling water to each of the water supply holes in response to variations in the thickness of the water film. A cooling pad for a belt-type continuous casting machine, characterized by being provided with a means for automatically changing the circulation area. 2. In the cooling pad according to claim 1, means for automatically changing the cooling water flow area is provided in each of the water supply holes, substantially in contact with the belt mold, and configured to automatically change the cooling water flow area. A cooling pad for a belt-type continuous casting machine, comprising a rod-shaped body that can slide toward and away from the belt mold in response to changes in film thickness.