JPH01113155A - Cooling pad for belt type continuous casting machine - Google Patents

Abstract

PURPOSE:To reduce deformation of a belt and to improve thickness accuracy of a cast slab by injecting cooling water from water supplying hole at pressure balancing with the molten metal static pressure and floating up the movable belt at position higher than the height of belt-like projection from surface of a cooling pad. CONSTITUTION:The pressurized cooling water supplied is injected from water supplying holes 9 at the pressure balancing with the molten metal static pressure and the movable belt 4 is floated up at the position higher than the height of the belt-like projections 16, 18 from the surface 40 of the cooling pad 6. Then, thickness of water film is made to thicker than the height of the projections 16, 18. The cooling water is drained through drainage hole 12 after cooling the movable belt 4. By such constitution, the deformation of the belt is reduced and the thickness accuracy of the cast slab is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a cooling pad for a belt-driven continuous casting machine, and particularly to a cooling pad for a hanging belt-type continuous casting machine that maintains the thickness of a slab slab with high precision. Concerning the cooling band.

[Conventional technology]

A belt-driven continuous casting machine uses a pair of movable belts that rotate opposite each other as widthwise molds, and injects molten metal between the belts, using a cooling pad provided in contact with the back side of the movable belts. , while supporting the pressure applied to the belt by the molten metal and simultaneously cooling and solidifying the molten metal via the movable belt with cooling water supplied from the water supply hole of the cooling pad, the gap between the movable belts is reduced to a plate thickness. The cast slab formed as a molten metal is pulled downward in a direction opposite to the molten metal injection side in synchronization with the rotation of the movable belt.

As a cooling pad for such a belt-type continuous casting device, Japanese Patent Application Publication No. 166145/1983 and Japanese Patent Publication No. 59/1989
- A cooling pad with a conventional structure in which a movable belt is supported in contact with a rib member provided in a cooling water flow path or a cooling water guide member is known, which is described in the specification of Publication No. 29345. In the cooling pad, the movable belt is abraded due to the contact between the rib member or the cooling water guide member and the movable belt, and hot spots occur due to the decrease in the movable belt cooling ability at this protruding contact area, which can easily cause damage to the movable belt. Not enough consideration was given.

On the other hand, in the apparatus described in Japanese Patent Application Laid-Open No. 129259/1980, hydrostatic pressure is applied from a cooling pad to balance the static pressure of molten steel, thereby floating the movable belt.

[Problem that the invention seeks to solve]

However, in the method described in JP-A-60-129259, there is no flow resistance adjustment mechanism between the water supply hole and the drain hole of the cooling pad, so the value varies depending on the position in the vertical direction (belt movement direction). In order to balance the hydrostatic pressure with the static pressure of molten steel, this can be done by providing a restriction in the drainage hole, or by changing the size and flow path distance of the water supply hole and drainage hole, as well as the water supply flow rate, depending on the vertical position of the cooling pad. However, it is difficult to balance the water supply flow rate for cooling the movable belt with the hydrostatic pressure for floating the movable belt. Moreover, this cooling-floating system has multiple water supply holes provided at the same height of the cooling pad that lug to a common water supply.
Since the position of the movable belt in the width direction causes an imbalance in the cooling water flow rate, the floating amount of the movable bell l- from the cooling pad surface fluctuates, and the movable belt is easily deformed. This may result in an unstable system in which the movable belt further deforms due to the action of hydrostatic pressure.

On the other hand, in order to reduce the deformation of the movable belt, the thickness of the water film formed between the movable belt and the cooling pad by cooling water is reduced to increase water film rigidity (the force that tries to keep the water film thickness constant). When trying to increase the water film, the flow resistance increases as the water film becomes thinner, and the amount of cooling water decreases rapidly. The flow changes from a turbulent flow to a transition region or a laminar flow region, and the heat transfer coefficient between the movable belt and the cooling water decreases, resulting in a decrease in the movable belt cooling performance, so there is a limit to increasing the water film rigidity.

In addition, this movable belt is treated as a consumable item that must be replaced frequently in terms of reliability, so a method of processing the movable belt to improve the heat transfer coefficient is economically disadvantageous.

Also, as in the invention described in JP-A No. 61-37355, the outlet of the water supply hole of the cooling pad is connected with a strip-shaped recess, or as in the invention described in JP-A-59-29345, the cooling pad is provided with a drainage hole. If only grooves are provided in the width direction of the movable belt, it is difficult to levitate the belt, and there is also the disadvantage that there is a large amount of side leakage in which cooling water flows out to both sides through the gap between the movable belt and the cooling pad. Ta.

An object of the present invention is to provide a cooling pad for a belt-type continuous casting machine that prevents the abrasion and deformation of the movable belt described above and simultaneously satisfies uniform floating of the movable belt and uniform cooling characteristics. Furthermore, belt type continuous casting prevents wear and deformation of the movable belt, satisfies uniform floating of the movable belt and uniform cooling performance, and reduces the amount of cooling water leaking in the width direction from the gap between the movable belt and the cooling pad. Our goal is to provide cooling pads for machines.

[Means for solving problems]

The above problem is solved in the cooling pad of a belt-type continuous casting machine that supports the back side of each of a pair of movable belts forming a mold in the width direction via a water film made of a cooling water flow flowing from a water supply hole to a drainage hole. A belt-type continuous casting machine comprising a belt-shaped protrusion extending transversely to the flow direction of the cooling water and having a thickness not exceeding the thickness of the water film on a surface of the cooling pad facing the movable belt. This is achieved by cooling pads.

The other problem described above is that the belt-shaped protrusions are provided, and that at least one of the belt-shaped protrusions extends transversely to the width direction of the movable belt for each water supply hole, and that the belt-shaped protrusions have a thickness. is achieved by a cooling pad of a belt caster equipped with a second band-shaped protrusion whose thickness does not exceed the thickness of the water film.

[Effect]

In the present invention, belt-shaped projections having a thickness smaller than the water film that levitates the movable belt are extended in a direction transverse to the flow of cooling water on the cooling pad, so that the projections and the belt are in contact with each other. Even if the belt does not wear out, the water film thickness is reduced, the water film rigidity is increased, the movable belt is floated uniformly, and belt deformation due to unbalanced cooling water flow is reduced. This promotes the turbulence of the cooling water flow and improves the heat transfer coefficient, so there is no reduction in cooling capacity.

Furthermore, the present invention is provided with a second belt-shaped projection extending transversely to the width direction of the belt and having a thickness not exceeding the thickness of the water film between the belt-shaped projections, so that the cooling water flow is reduced. The band-shaped protrusions extending laterally to the movable belt prevent the cooling water from flowing along the width direction of the movable belt, and the amount of side leakage of cooling water leaking in the width direction from between the movable belt and the cooling pad is reduced. Ru.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

The twin-belt continuous casting machine shown in FIG. The 7s steel is injected into a mold formed by a pair of short pieces 5, and is cooled and solidified by cooling water jetted from a cooling pad 6 provided on the back of the surface of the movable belt 4 that contacts the molten steel. The slab 8, which is synchronized with the movable belt 4 rotating together with the roller 7, is taken out below the mold.

In this continuous casting machine, the static pressure of molten steel is applied to the movable belt, so the movable belt 4 is
Pressurized cooling water is jetted out from the cooling water supply hole 9 on the back side of the movable belt 4 and the cooling pad 6 to form a water film 10 between the movable belt 4 and the cooling pad 6 by applying hydrostatic pressure. A gap is maintained between the two.

FIGS. 2 and 3 show the cooling pad in detail, and the water supply hole 9 is formed depending on the thickness of the water film 10 between the movable belt 4 and the cooling pad 6, the static pressure of molten steel, the amount of cooling water, etc. Cooling pad 6 with the determined minimum interval
The water supply holes are arranged in a row on a straight line that is parallel to the width direction of the movable belt and spaced at a predetermined interval in the belt movement direction, and generally the water supply holes are arranged in a row in the belt width direction in the belt movement direction. The spacing between the water supply holes is narrower than that in . The water supply hole 9 communicates with a water supply header 11 inside the cooling pad 6, and the water supply header 11 is connected to a water supply pump (
(not shown).

Further, the drain holes 12 are similarly arranged in a row in the belt width direction between the rows of the water supply holes 9, and communicate with the drain flow path 13. Three belt-shaped protrusions for promoting turbulent flow according to the present invention are arranged parallel to the width direction of the movable belt 4 between each water supply hole 9 and drain hole 12 on the surface of the cooling pad 6. At least one second band-shaped projection for preventing drifting is provided for each water supply hole between each of the band-like projection members 16 and between each of the water supply holes 9. It consists of an intermittent band-shaped protrusion member 18 extending transversely to the belt width direction. Further, these projecting members 16 and 18 are made of a material thinner than the thickness of the water film 10, and the belt is directly connected to the projecting members 1.
6 so as not to come into contact with it. Furthermore, the vertical cross-sectional area of the cooling water formed by the band-like projection member 16 and the movable belt 4 is larger than the cross-sectional area of the water supply hole 9 in the vertical direction relative to one row of water supply holes arranged in a row in the belt width direction. It is larger than the total cross-sectional area of the cooling water flow path of the water supply hole group 9' added together, and the flow path cross-sectional area of the drain hole 12 is set to be larger than the total cross-sectional area of the cooling water flow path of the water supply hole group 9', and the flow path cross-sectional area of the drain hole 12 is set to be larger than the total cross-sectional area of the cooling water flow path of the water supply hole group 9'. It is set to be smaller than the total cross-sectional area of the cooling water flow path of the drain hole group 12'.

Next, the operation of this embodiment will be explained. Water pump (
The pressurized cooling water supplied by the cooling pad (not shown) is ejected from the water supply hole 9 with a pressure that balances the static pressure of the molten steel, and moves the movable belt 4 from the surface 40 of the cooling pad 6 to the strip protrusion 16.
and floating higher than the height of the second band-shaped projection 18,
After cooling the movable belt 4 while passing through a flow path formed by the movable belt 4 and a belt-shaped protrusion 16 provided on the surface of the cooling pad 6, the water is discharged to the outside of the machine from a drainage flow path 13 through a drainage hole 12. Ru. Therefore, like a traditional continuous casting machine,
Since the belt 4 and the protrusions on the surface of the cooling pad do not come into contact with each other, the belt does not wear out, and the heat transfer coefficient between the cooling water and the belt is reduced by the turbulent flow promoting effect of the band-shaped protrusions 16. This increases the belt cooling performance.

Moreover.

This prevents the occurrence of belt hot spots due to a decrease in belt cooling ability at protruding contact parts caused by contact with the belt, as seen in the rib members or cooling water guide members of conventional devices.
A more reliable continuous casting machine can be achieved.

Further, in this embodiment, the belt-like projection 16 and the movable belt 4
The cross-sectional area of the cooling water flow path formed by the cooling water flow path is larger than the total cross-sectional area of the cooling water flow path of the water supply hole group 9' and smaller than the total cross-sectional area of the cooling water flow path of the drain hole group 12'. Therefore, when balancing the hydrostatic pressure of the cooling water with the static pressure of molten steel, which varies depending on the position in the belt movement direction (continuous caster height direction), the strip-shaped protrusion 16 By selecting a small value for the flow resistance distribution and the water film thickness 10 to increase the restoring force against deformation of the belt 4, deformation of the belt can be prevented. We can provide a strong cooling pad.

In this embodiment, even if the water film thickness is increased to increase the water film rigidity and the cooling water flow rate is reduced as a result, the cooling water and the movable belt are Since the heat transfer coefficient between the two is significantly improved, both high water film rigidity and high cooling capacity can be obtained. Since high water film rigidity is obtained, the deformation of the movable belt 4 is small, and a continuous casting machine that produces slabs with good plate thickness accuracy can be obtained.

Also against deformation of the movable belt in the slab width direction.

In this embodiment, since the second belt-shaped protrusion is provided which extends in the transverse direction to the belt width direction and prevents the cooling water from drifting in the belt width direction, cooling in the movable belt width direction is provided. The water flow resistance is increased, the amount of cooling water jetted from the water supply hole is reduced in the width direction of the movable belt, and the amount of side leakage flowing to the ends of the movable belt in the width direction is also reduced.

If the distance between the movable belt and the cooling pad surface 40 is
Even if the movable belt changes in the width direction, the hydrostatic pressure of the cooling water jetted from the water supply hole 9 is kept constant by the water supply header 11, and the water supply hole 9 is a small flow part of the cross section of the cooling water flow path. Above, the force for restoring the deformed movable belt due to the static pressure of molten steel applied to the movable belt 4 increases;
The ability to uniformly levitate the movable belt in the width direction and cool it has been greatly improved.

Next, the deformation and restoring force of the movable belt in the moving direction of the movable belt will be explained. FIG. 4 shows the cooling water hydrostatic pressure distribution (solid line) and the molten steel static pressure distribution (broken line) of the cooling pad in a conventional belt-type continuous casting machine. Conventional continuous casters are designed to reduce the diameter of the drainage hole and increase the hydrostatic pressure at the drainage hole in order to balance the hydrostatic pressure of the cooling water with the static pressure of molten steel, resulting in a pressure distribution like the solid line. Ta. in this case,
If the shape of the belt 4 in the belt movement direction is deformed for some reason, the total cross-sectional area of the drain holes is narrower than the total cross-sectional area of the water supply holes, so the pressure at the drain hole portion will vary greatly depending on the amount of deformation. In some cases, the deformation is further promoted, and not only is the plate thickness of the slab not maintained accurately, but the cooling water flow path is blocked, the belt temperature rises, and the belt 4 may seize.

On the other hand, FIG. 5 shows the hydrostatic pressure distribution according to the present invention. In the case of the present invention, the belt 4 is supported by the water supply holes scattered on the surface of the cooling pad 6, and the water drain holes are Since there is no need to maintain static pressure at , the hydrostatic pressure has a distribution shown by the solid line in Figure 5, and even if the belt 4 is slightly deformed, the hydrostatic pressure distribution acts to restore the belt 4 to the equilibrium position.
The amount of belt deformation can be minimized without increasing the amount of belt deformation.

Further, FIGS. 6 and 7 show a second embodiment of the present invention. In the second embodiment, a groove 21 is provided between the water supply hole 9 and the drainage hole 12 of the cooling pad 6.
A belt-shaped protrusion 16 for promoting turbulent flow and a second belt-shaped protrusion for preventing drifting consisting of one intermittent strip-shaped protrusion member 23 for at least one water supply hole are provided in the water supply hole. It has exactly the same functions and effects as the band-shaped projection 16 and the second band-shaped projection 18 of the first embodiment.

Furthermore, in the third embodiment shown in FIG. 8, an intermittent band-like protrusion member 30 is provided in place of the band-like protrusion member 16 that is continuous in the width direction of the movable belt shown in FIG. It has almost the same function and effect as the band-shaped projection 16. In this case, since the flow resistance in the belt movement direction is rather reduced, the second band-shaped protrusion 18 for preventing the drifting flow may be omitted in some cases. Furthermore, as shown in FIG. 8, the drain hole 31 may be formed into a slit shape to further reduce the flow resistance of the drain.

FIG. 9 shows a fourth embodiment in which a band-shaped protrusion for promoting turbulent flow is formed as an assembly of distorted protrusion members 35, and the distorted protrusion members 35 are arranged diagonally on the surface of the cooling pad 6. Since it can be manufactured by cutting multiple grooves in a row, it has the effect of reducing pad manufacturing costs. The performance of belt cooling flotation can be improved by changing the size and depth of this groove to promote turbulence and prevent drift, so this embodiment also has almost the same function as the first embodiment.

〔Effect of the invention〕

According to the present invention, on the surface of the cooling pad of a belt-type continuous casting machine facing the movable belt, a belt-shaped belt extending transversely to the flow direction of the cooling water and having a thickness not exceeding the thickness of the water film is provided. Equipped with protrusions, it is possible to reduce the water film thickness and increase the water film rigidity, allowing the movable belt to float accurately and uniformly, reducing movable belt deformation and improving slab thickness accuracy. effective.

Furthermore, in addition to the band-shaped protrusions, a second band-shaped protrusion is provided to prevent the cooling water from drifting in the width direction of the movable belt, so in addition to the above-mentioned effect, the amount of leakage of the cooling water from the ends of the movable belt in the width direction is reduced. This has the effect of reducing the amount of power used by the cooling water pump.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing the first embodiment of the present invention, and the second embodiment
The figure is a detailed view of the cooling pad in Figure 1, Figure 3 is a sectional view taken along line A-A in Figure 2, and Figure 4 is an explanatory diagram showing the hydrostatic pressure distribution of a conventional belt type continuous casting machine. FIG. 5 is an explanatory diagram showing the hydrostatic pressure distribution of a continuous casting machine to which the present invention is applied, FIG. 6 is a detailed diagram of the cooling pad showing the second embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along line A-A in the figure, FIG. 8 is a diagram showing a third embodiment of the present invention, and FIG. 9 is a detailed view of a cooling pad showing a fourth embodiment of the present invention. 4... Movable belt, 6... Cooling pad, 9... Water supply hole, 12... Drain hole, 16... Band-shaped projection, 18
...Second band-shaped protrusion.

Claims (1)

[Claims] 1. A cooling pad for a belt-type continuous casting machine that supports the back side of each of a pair of movable belts forming a mold in the width direction via a water film made of a cooling water flow flowing from a water supply hole to a drainage hole. In this method, the surface of the cooling pad facing the movable belt is provided with a band-shaped protrusion that extends transversely to the flow direction of the cooling water and whose thickness does not exceed the thickness of the water film. A cooling pad for a belt-type continuous casting machine featuring the following. 2. The cross-sectional area in the mold width direction of the cooling water flow path formed by the band-shaped projections provided on the cooling pad and the back surface of the movable belt is larger than the sum of the cross-sectional areas of the water supply holes arranged in a line in the mold width direction; The cooling pad for a belt-type continuous casting machine according to claim 1, wherein the cooling pad is smaller than the sum of the drainage holes arranged in a line in the mold width direction. 3. In a cooling pad for a belt-type continuous casting machine that supports the back side of each of a pair of movable belts forming a mold in the width direction via a water film made of a cooling water flow flowing from a water supply hole to a drainage hole, The surface facing the movable belt is provided with band-shaped protrusions that extend transversely to the flow direction of the cooling water and whose thickness does not exceed the thickness of the water film, and water is supplied between the band-shaped protrusions. Each hole is provided with at least one second band-shaped protrusion that extends transversely to the width direction of the movable belt and has a thickness that does not exceed the thickness of the water film. Cooling pad for belt type continuous casting machine. 4. The cross-sectional area in the mold width direction of the cooling water flow path provided on the cooling pad and formed by the band-shaped protrusions and the back surface of the movable belt is greater than the sum of the cross-sectional areas of the water supply holes arranged in a row along the mold width direction. 4. The cooling pad for a belt-type continuous casting machine according to claim 3, wherein the cooling pad is larger than the sum of the drainage holes arranged in a row along the mold width direction. 5. Claims 1 to 5, characterized in that the band-shaped protrusions are provided intermittently parallel to the width direction of the mold.
A cooling pad for a belt type continuous casting machine according to any one of Item 4. 6. According to any one of claims 1 to 5, the belt-shaped protrusion is provided in a groove structure provided on the surface of the cooling pad facing the movable belt. Cooling pad for belt type continuous casting machine.