KR101481616B1 - Apparatus for cooling strip - Google Patents

Abstract

A rolling material cooling apparatus according to an embodiment of the present invention includes a water tank that is arranged above a rolling material, has an accommodating space for accommodating a first refrigerant supplied from the outside, and has a plurality of injection holes to inject the refrigerant in a width direction of the rolling material; at least one blocking plate that is disposed to be upright and protrude from a bottom surface in the accommodating space and partitions the inner space into first and second water supply spaces; a supply line that is disposed below the rolling material, is arranged in the width direction of the rolling material, and allows a second refrigerant to flow after being supplied from the outside; first cooling headers that are arranged to be at a predetermined distance from each other in the longitudinal direction of the supply line and are capable of injecting the second refrigerant to the rolling material; and second cooling headers that are arranged to be at a predetermined distance from each other in the longitudinal direction of the supply line, are disposed in behind the first cooling headers from the transport direction of the rolling material, and are capable of injecting the second refrigerant to the rolling material.

Description

{APPARATUS FOR COOLING STRIP}

The present invention relates to a rolling material cooling apparatus, and more particularly, to a cooling apparatus for cooling a rolled material by minimizing a cooling deviation generated at a central portion and an edge portion of a rolling material, And cooling the rolled material.

Generally, in the hot rolling process for producing hot-rolled steel sheets, the slabs produced in the continuous casting process are heated to a certain temperature in the heating furnace, then rolled in the form of bars in the rough rolling process, Rolling. Subsequently, the steel sheet extracted from the back side of the rolling mill is measured by finishing delivery temperature (FDT) using a finishing rolling temperature measuring apparatus, and air cooling and forced water cooling The temperature is appropriately lowered through the process, and the target coiling temperature (CT) is secured by using a coiling temperature measuring device. Then, the coiling machine is produced as a roll coil type hot coil.

That is, a steel sheet having a target thickness and width at a finish rolling temperature of 800 to 900 ° C. through a continuous hot rolling process is transferred to a water-cooled state and is quenched to a coiling temperature of 300 to 700 ° C. to have physical properties as a steel product. In a general hot-rolled steel sheet, only the temperature at the edge portion is formed to be several tens of degrees lower than that at the center portion, and the central portion temperature is maintained to be relatively uniform. This is mainly because the width of the steel sheet is larger than the thickness of the steel sheet. Since the edge of the steel sheet is exposed to air more than the center portion, the steel sheet is exposed to the air, .

Further, due to the characteristics of the cooling equipment, the cooling amount is larger in the upper surface than in the lower surface, and cooling differences are generated in the upper and lower surfaces in which the cooling amount is large. When a cooling deviation occurs, the upper portion of the steel which has been cooled more than the lower portion is further subjected to a volume contraction, and the steel sheet becomes a concave shape with a concave toward the upper portion. There is a problem that the cooling water becomes high on the upper surface of the steel plate which is concave toward the upper side and the part where the cooling water is high becomes the localized subcooling, causing a material deviation.

Korean Patent Registration No. 10-1089330. December 2, 2011.

An object of the present invention is to provide a rolled material excellent in quality and productivity by preventing surface defects generated in a process of cooling a rolled material.

Another object of the present invention is to minimize the cooling deflection of the rolled material to reduce the plate shape defects.

Other objects of the present invention will become more apparent from the following detailed description and drawings.

According to an embodiment of the present invention, a rolling material cooling apparatus includes a plurality of first cooling media disposed in an upper portion of a rolled material and having a receiving space for receiving a first refrigerant supplied from the outside, A water tank in which jet holes are formed; At least one blocking plate protruding from a bottom surface in the accommodating space and each standing up to partition the inner space into a first water supply space and a second non-water supply space; A supply line disposed below the rolled material and disposed along the width direction of the rolled material and through which a second refrigerant supplied from the outside flows; A first cooling header spaced apart at predetermined intervals along a longitudinal direction of the supply line and capable of ejecting the second refrigerant toward the rolling material; And a second cooling header disposed at a predetermined interval along the longitudinal direction of the supply line and disposed behind the first cooling header with respect to the conveying direction of the rolled material so as to discharge the second refrigerant toward the rolling material, Cooling header.

The rolling material cooling apparatus includes at least one auxiliary blocking plate protruding from a bottom surface in the first water supply space and rising and standing separately and partitioning the first water supply space into a second water supply space and a second non-water supply space .

The bottom plate of the water tank has a horizontal plate shape. The upper end of the blocking plate may be lower than the upper end of the side plate of the water tank, and the upper end of the auxiliary blocking plate may be lower than the upper end of the blocking plate.

The water tank is formed at a central portion of the water tank and has an inlet through which the first refrigerant flows, and the blocking plate and the auxiliary blocking plate may be disposed on both sides of the center of the water tank.

Wherein a distance between a front line in which the first cooling header is arranged and a rear line in which the second cooling header is arranged is smaller than a sum of a radius of the first cooling header and a radius of the second cooling header, Is smaller than the diameter of the second cooling header, and the center of the second cooling header may be disposed at a position between the first cooling headers of the rear lines.

The first cooling header and the second cooling header may inject the second refrigerant at an angle toward the traveling direction of the rolling material.

Wherein one of the first cooling header and the second cooling header is injected obliquely in the direction of travel of the rolling material to the supply line and the other one of the first cooling header and the second cooling header moves in the vertical direction of the rolling material As shown in FIG.

Wherein the direction of the second coolant injected obliquely toward the rolling material through the first cooling header and the second cooling header is not more than 15 degrees (but excluding 0) on the basis of the vertical direction of the rolling material in the supply line As shown in Fig.

According to one embodiment of the present invention, defective shape, particularly edge wave, of the rolled material generated during the step of cooling the rolled material to the coiling temperature can be minimized. Further, by providing at least one blocking plate in the inner space of the lamina bank, the temperature in the width direction of the rolled material can be uniformly controlled. In addition, the cooling deviation generated during the cooling of the upper and lower portions of the rolled material is improved, and uniform cooling can be performed, so that the defective shape that becomes concave toward the upper portion can be improved. Therefore, the temperature in the width direction and the upper and lower portions of the rolled material can be uniformly controlled, thereby improving the quality and productivity.

1 is a view schematically showing a general hot rolling apparatus.
2 is a schematic view of a rolling material cooling apparatus according to an embodiment of the present invention.
3 is an enlarged view of A shown in Fig.
4 is a cross-sectional view of the water tank shown in Fig.
5 and 6 are views showing an operation process of the water tank shown in FIG.
Fig. 7 is a view showing the arrangement of the first and second cooling headers shown in Fig. 3. Fig.
8 is a view showing the operating states of the first and second cooling headers shown in Fig.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to FIGS. 2 to 8 attached hereto. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments are provided to explain the present invention to a person having ordinary skill in the art to which the present invention belongs. Thus, the shape of each element shown in the figures may be exaggerated to emphasize a clear description. It is obvious to a person skilled in the art that the present invention can be applied to various plate materials besides the steel plates described in the embodiments.

1 is a view schematically showing a general hot rolling apparatus. As shown in Fig. 1, the hot rolling apparatus includes a heating furnace 2 for heating a steel sheet S, for example, a slab, a roughing mill for roughing the rolled material heated in the heating furnace 2 A finishing mill 6 for finishing and rolling a rough-rolled material (for example, a bar), a finish-rolled material (for example, a strip) A run out table (ROT) 7 and a winder 9 for winding the rolled rolled material into coils.

The steel sheet S passes through the heating furnace 2, the rough rolling mill 4, the finishing mill 6, the ROT 7 and the winder 9 in this order and is wound into coils. When the steel sheet S advances to the finishing mill 6, the rolling speeds of the plurality of mills provided in the finishing mill 6 are individually controlled to finishing the rolling material. Thus, after the rolled material S is heated in the heating furnace 2, all the overall work which is wound into the coil by the winder 9 is generally called "hot rolling".

During the hot rolling process, the ROT 7 is a process in which the steel sheet S is fed before the final rolled material, that is, the steel sheet S is wound in the winder 9, through the heating furnace 2 and rough rolling, The steel sheet S is cooled to the target temperature in this process to determine the material and strength of the product. At this time, strip wave generation, which is a defective shape due to a cooling deviation in the width direction, is caused by a problem of permanentity.

In other words, in the ROT 7, the cooling water dropped to the central portion in the width direction of the steel strip S during cooling flows out through the edge portion of the steel strip S, so that the temperature of the edge portion of the steel strip S is lowered. In this process, first, the volume contraction of the cooled or subcooled steel sheet S is caused, followed by the volume contraction of the central portion of the steel sheet S to be cooled. This difference in temperature results in a difference in volume shrinkage time, which is expressed in the form of a wave of the steel sheet S.

Particularly, in the cooling process during the hot rolling process, since the steel sheet S is cooled at a high temperature of 600 ° C. or more, a transformation section occurs during cooling depending on the kind of steel, which causes volume expansion. At the edge of the steel sheet S to be cooled first. Therefore, when the edge transformation begins at a predetermined section, the cooled edge first expands in volume and the central portion of the high temperature that has not yet entered the transformation section is cooled, causing the volume to contract. This phenomenon causes a wave of the edge portion It is a typical mechanism.

In addition, in the conventional case, the cooling headers are generally composed of the same number of cooling headers in the upper and lower cooling systems. The cooling pattern for reducing the cooling deviation generated in the upper and lower portions of the steel sheet S when the conventional cooling is performed must be such that the cooling liquid is discharged from half of the entire header and the cooling liquid is discharged from the entire header at the lower portion.

However, this conventional method is problematic in the case of increasing the amount of cooling in steel which requires high strength. However, in this case, since the entire header is used in the lower part, the amount of the upper cooling must be increased. Further, the space for installing the additional nozzles is required to increase the amount of the lower cooling, but there is a limitation in space, and the number of the lower cooling headers can not be increased.

When the amount of cooling of the upper part is increased, the amount of cooling is increased at the upper part relative to the lower part, resulting in a concave shape of the concave toward the upper part. Thus, in the case of high strength steel (TS 500Mpa or more) It is impossible. In the production of such high-strength steels, the current upper cooling amount is increased to secure the strength required by the customer, and the shape defects due to the upper and lower cooling deviations of the high-strength steels frequently occur. In order to solve the above-mentioned problems, a rolling material cooling apparatus capable of easily cooling the steel sheet S will be described below.

FIG. 2 is a schematic view of a rolling material cooling apparatus according to an embodiment of the present invention, and FIG. 3 is an enlarged view of A shown in FIG. 2 and 3, the lamina bank 20 is installed on the upper part of a roller table 14 for transferring the steel sheet S rolled in the rolling mill 13, A plurality of injection holes 28 are formed on the bottom surface in a lengthwise or widthwise direction at regular intervals to inject water into the upper portion of the syringe S.

The lamina bank 20 is connected to the reservoir tank 30 through the upper supply pipe 35 and the cooling water stored in the reservoir tank 30 is injected into the lamina bank 20 through the upper supply pipe 35 . At this time, the reservoir tank 30 can be disposed at a relatively higher position than the laminar bank 20 so that the cooling water of the reservoir tank 30 can be injected into the laminar bank 20 by gravity.

The upper supply pipe 35 connects the reservoir tank 30 and the lamina bank 20 and the cooling water stored in the reservoir tank 30 is buffered in the lamina bank 20 through the upper supply pipe 35. A separate pump (not shown) is connected to the upper supply pipe 35 and is pumped toward the laminar bank 20 to supply the cooling water. The first valve 32 is installed in the upper supply pipe 35, The cooling water supplied through the supply pipe 35 can be controlled. Further, a sensor (not shown) may be disposed on the inlet side and the outlet side, respectively, with reference to the traveling direction of the steel plate S, and a controller (not shown) The flow rate of the laminar bank 20 can be controlled by controlling the first valve 32.

The first cooling header 12 and the second cooling header 18 are spaced apart from one end of the supply line 10 and the steel plate S S) in the front and rear direction, respectively. The number of cooling headers can be increased with respect to the same supply line 10 when the first cooling header 12 is arranged in a zigzag form. When the number of the headers on the same supply line 10 increases, the maximum discharge amount of the cooling water by the first cooling header 12 and the second cooling header 18 installed on the supply line 10 increases, To be maintained. The supply line 10 is connected to the lower supply line 13 and the second valve 14 is provided on the lower supply line to control the supply amount of the coolant to the supply line 10. The description of the first and second cooling headers 12 and 18 provided in the supply line 10 and the supply line 10 will be described later.

4 is a cross-sectional view of the water tank shown in Fig. The steel plate cooling apparatus 100 is disposed at the upper and lower portions of the steel sheet S to spray the coolant in the width direction of the steel sheet S, and the coolant may be cooling water. The lamina bank 20 has an accommodation space for accommodating the cooling water supplied from the upper supply pipe 35 and a plurality of injection holes 28 are formed in the bottom plate 25 of the lamina bank 20. The injection holes 28 may be formed in a plurality of rows in the width direction of the steel sheet S at predetermined intervals to inject cooling water into the upper portion of the steel sheet S. [ Further, the bottom plate 25 may have a shape parallel to the steel sheet S.

The first and second blocking plates 40 and 40 'protruding from the bottom plate 25 in the receiving space of the lamina bank 20 are installed upright along the width direction of the steel plate S, The plates 40 and 40 'partition the receiving space into a first water supply space and a first non-water supply space. An inlet 38 is formed at the center of the lamina bank 20 to flow in from the upper supply pipe 35. The cooling water is buffered in the first water supply space by the first and second blocking plates 40 and 40 ' And is injected into the steel sheet S through the injection holes 28. The inlet 38 may be formed at the center of the upper plate 22 of the lamina bank 20 or at the center of the front plate or the rear plate about the longitudinal direction of the steel plate S so that the cooling water may flow into the first water supply space.

The first and second auxiliary blocking plates 50 and 50 'protrude from the bottom surface in the first water supply space and are respectively installed to partition the first water supply space into the second water supply space and the second non-water supply space. The upper ends of the first and second auxiliary blocking plates 50 and 50 'have lower heights than the upper ends of the first and second blocking plates 40 and 40', and the first and second blocking plates 40 and 40 ' Has a lower height than the side plate 24 of the lamina bank.

Therefore, the cooling water flows into the second water supply space through the inlet 38 formed at the central portion. When the flow rate of the cooling water increases, the cooling water can be sequentially introduced into the second non-water supply space and the first non-water supply space. That is, the height of the cooling water is adjusted so that the main water width of the cooling water injected through the injection hole 28 can be adjusted. The operation process according to the flow rate of the cooling water supplied to the lamina bank 20 will be described with reference to the following figures.

5 and 6 are views showing an operation process of the water tank shown in FIG. The height of the cooling water flowing into the space between the first and second auxiliary blocking plates 50 and 50 '(the second water supply space) is controlled by controlling the flow rate of the cooling water, as shown in FIG. 5, (W) can be adjusted so that cooling water is supplied to the center of the tube (T). When the flow rate is increased by adjusting the valve 32, as shown in FIG. 6, the cooling water flows into the space between the first and second shield plates 40 and 40 '(the first water supply space) (W) can be increased.

For example, it is desirable to set the main water width W to be about 70% to 90% of the entire width of the steel plate, and to adjust the flow rate of the cooling water to be supplied to the laminar bank 20 32 to control the temperature of the steel sheet S to be uniformly cooled by supplying cooling water to the predetermined main water width W. [

Fig. 7 is a view showing the arrangement of the first and second cooling headers shown in Fig. 3. Fig. 7, the distance d ₁ between the front line in which the first cooling header 12 is arranged and the rear line in which the second cooling header 18 is arranged is smaller than the radius d ₁ of the first cooling header 12 r ₁ of the second cooling header 18 and the radius r ₂ of the second cooling header 18. The distance d ₂ between the first cooling header 12 is smaller than twice the radius r ₂ of the second cooling header 18 and the center of the second cooling header is smaller than the radius r ₂ of the first cooling header 12, As shown in Fig. For example, the diameter of the supply line 10 is 100 mm, the diameter of the first cooling header 12 and the second cooling header 18 is 50 mm, the diameter of the nozzle 16 is 25 mm, .

8 is a view showing the operating states of the first and second cooling headers shown in Fig. As shown in Fig. 8, the first cooling header 12 and the second cooling header 18 are arranged obliquely with respect to the supply line 10. The spraying angle of the nozzle 16 is arranged to be inclined from the vertical direction toward the steel plate S toward the traveling direction of the steel plate S toward the existing steel plate S.

At this time, the injection angle of the cooling water is arranged at a maximum angle of 15 degrees with respect to the vertical direction from the supply line 10 to the steel plate S so as to avoid facility interference by the table roller 8. [ It is possible to simultaneously improve the cooling effect by increasing the lower cooling region and also to prevent the entrance of the nozzle 16 from clogging due to scales and foreign substances falling from the steel sheet S additionally.

Also, the first cooling header 12 may be disposed at an angle of 15 degrees toward the direction of conveyance of the steel sheet, and the second cooling header 18 may be disposed at an angle of 15 degrees toward the direction opposite to the conveyance of the steel sheet. By arranging the first and second cooling headers 12 and 18 different from each other, it is possible to achieve uniform cooling by widening the cooling range for the steel plate.

That is, according to the present invention, the edge portion of the steel sheet S has a larger area exposed to the air than the center portion, and the temperature drop due to secondary cooling due to the number of cooling residues is large, so that the temperature deviation between the center portion and the edge portion becomes large. On the other hand, by selectively supplying cooling water through the steel plate cooling apparatus 100 according to the present invention in the width direction of the steel plate S, temperature variation in the width direction of the steel plate S can be prevented, Whereby an excellent high strength steel sheet (S) can be produced.

Further, when cooling water is injected in the same direction in the width direction of the surface of the steel sheet S, the same cooling water injected in the upper part of the steel sheet S actually imbalances the cooling of the steel sheet S and adversely affects the quality. On the other hand, according to the present invention, by controlling the water supply section in accordance with the flow rate of the cooling water corresponding to the entire width T of the steel plate S, it is possible to prevent the cooling water from being directly supplied to the edge portion of the steel plate S, Can be reduced.

Therefore, it is possible to improve the easiness of manufacture and the stability of water injection by improving the cost, high complexity in installation, frequent failures due to complicated structure and materials, poor operating environment, which occurred in the existing edge mask system, The supercooling of the steel plate edge portion can be prevented. In addition, the cooling deviation generated during the cooling of the upper and lower portions of the rolled material is improved, and uniform cooling can be performed, so that the defective shape that becomes concave toward the upper portion can be improved. In addition, the temperature in the width direction and the upper and lower portions of the rolled material can be uniformly controlled, thereby improving productivity and quality, thereby maximizing productivity.

Although the present invention has been described in detail by way of examples, other forms of embodiments are possible. Therefore, the technical idea and scope of the claims set forth below are not limited to the embodiments.

2: heating zone 4: rough rolling mill
6: Finishing mill 7: ROT
9: Winder 10: Supply line
12: first cooling header 18: second cooling header
20: Lamina Bank 30: Reservoir tank
40: first blocking plate 40 ': second blocking plate
50: first auxiliary blocking plate 50 ': second auxiliary blocking plate

Claims (8)

A water tank having an accommodating space for accommodating a first refrigerant supplied from the outside and disposed in an upper portion of the rolled material and having a plurality of injection holes for injecting a coolant in a width direction of the rolled material;
At least one blocking plate protruding from a bottom surface in the accommodating space and each standing up to partition the accommodating space into a first water supply space and a first non-water supply space;
An upper supply pipe installed at an upper center of the water tub to inject the first refrigerant into the first water supply space;
A supply line disposed below the rolled material and disposed along the width direction of the rolled material and through which a second refrigerant supplied from the outside flows;
A first cooling header spaced apart at predetermined intervals along a longitudinal direction of the supply line and capable of ejecting the second refrigerant toward the rolling material; And
Wherein the first cooling header and the second cooling medium are spaced apart from each other at predetermined intervals along the longitudinal direction of the supply line and are disposed behind the first cooling header with respect to the conveying direction of the rolling material, Header,
Wherein the blocking plate is disposed on both sides with respect to the upper supply pipe, and when the level of the first refrigerant injected into the first water supply space is lower than the upper end of the blocking plate, the first refrigerant flows into the first non- Blocking movement,
Wherein the injection holes are formed in the first water supply space and the first non-aqueous space, respectively. A water tank having an accommodating space for accommodating a first refrigerant supplied from the outside and disposed in an upper portion of the rolled material and having a plurality of injection holes for injecting a coolant in a width direction of the rolled material;
At least one blocking plate protruding from a bottom surface in the accommodating space and each standing up to partition the accommodating space into a first water supply space and a first non-water supply space;
A supply line disposed below the rolled material and disposed along the width direction of the rolled material and through which a second refrigerant supplied from the outside flows;
A first cooling header spaced apart at predetermined intervals along a longitudinal direction of the supply line and capable of ejecting the second refrigerant toward the rolling material;
Wherein the first cooling header and the second cooling medium are spaced apart from each other at predetermined intervals along the longitudinal direction of the supply line and are disposed behind the first cooling header with respect to the conveying direction of the rolling material, Header; And
And one or more auxiliary blocking plates protruding from the bottom surface in the first water supply space and standing up from each other and partitioning the first water supply space into a second water supply space and a second non-water supply space. 3. The method of claim 2,
The bottom plate of the water tank has a horizontal plate shape,
Wherein the upper end of the blocking plate is lower than the upper end of the side plate of the water tank and the upper end of the auxiliary blocking plate is lower than the upper end of the blocking plate. 3. The method of claim 2,
Wherein the water tank is formed at a central portion of the water tank and has an inlet through which the first refrigerant flows,
Wherein the blocking plate and the auxiliary blocking plate are disposed on both sides of the central portion of the water tank, respectively. 3. The method according to claim 1 or 2,
Wherein a distance between a front line in which the first cooling header is arranged and a rear line in which the second cooling header is arranged is smaller than a sum of a radius of the first cooling header and a radius of the second cooling header, Is smaller than the diameter of the second cooling header, and the center of the second cooling header is disposed at a position between the first cooling headers of the rear lines. The method according to claim 1,
Wherein the first cooling header and the second cooling header obliquely eject the second refrigerant toward the traveling direction of the rolling material. The method according to claim 1,
Wherein one of the first cooling header and the second cooling header is injected obliquely in the direction of travel of the rolling material to the supply line and the other one of the first cooling header and the second cooling header is opposite to the traveling direction of the rolling material in the vertical direction of the rolling material The rolling material cooling device. 8. The method according to claim 6 or 7,
Wherein the direction of the second coolant injected obliquely toward the rolling material through the first cooling header and the second cooling header is not more than 15 degrees (but excluding 0) on the basis of the vertical direction of the rolling material in the supply line ) Of the rolled material.

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