JPH0995741A - Cooling zone of continuous annealing furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce the flow-out of spouting gas from a plenum chamber into a hearth roll side by arranging seal rolls as the vertically zigzag state in nozzle group side ejecting cooling gas in a gas ejecting cooling zone. SOLUTION: A steel sheet 1 is passed through a slitting through-hole 6 of a partition wall 5 parting the setting positions of the faced nozzle 4 group for injecting the cooling gas and a hearth roll 10 in the upper part, and the lower part, and supplied to and fed out between the faced nozzle 4 group with the hearth roll 10. In the cooling zone of this continuous annealing furnace, the upper and the lower seal rolls 2, 3 are arranged as the vertically zigzag state so that only one side roll surface in both seal rolls separately contacts with each surface in both surfaces of the steel sheet 1 at the faced nozzle 4 group side, respectively. By this constitution, the gas between the steel sheet 1 and the seal roll can be eliminated and the flow-out of the cooling gas from the cooling zone can further be prevented in comparison with the conventional furnace. Further, a distance between the faced nozzle group seal rolls and the partition wall 5 can be made to long and it can be prevented that the ejection gas is invaded to the hearth roll 10 side from the through hole 6 while rounding the width direction of the roll.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas sealing device for a so-called continuous annealing furnace for continuously annealing a steel strip, and more particularly,
In a gas injection cooling zone of the continuous annealing furnace (hereinafter, simply referred to as a cooling zone), the present invention relates to a gas sealing device for dividing the inside of the furnace into a plurality of regions by partition walls and providing each region with a unique atmosphere.

[0002]

2. Description of the Related Art In the cooling zone of a continuous annealing furnace for continuously annealing a steel strip, cooling equipment by gas injection as shown in FIG. 7 is usually provided. The equipment is roll room 1
When the high temperature steel strip 1 passing through the hearth roll 10 in 4 passes between the gas injection nozzle groups 4 of the plenum chamber 12, it is cooled by the gas injected from the nozzle groups 4. In FIG. 7, only the side for supplying the high temperature steel strip 1 to the plenum chamber 12 is shown, and the extraction side is omitted.

On the other hand, a part of the gas injected from the nozzle group 4 collides with the steel strip 1 and then descends or rises along the steel strip 1 to form a slit in the partition wall 5 with the roll chamber 14. It goes through the through hole 6 and enters the vicinity of the hearth roll 10.
Further, the steel strip 1 has a high temperature of several hundred degrees Celsius even during cooling,
Since the cooling gas has a temperature of about 100 ° C., a temperature difference occurs between the portions of the hearth roll 10 that are in contact with the steel strip 1 and the portions near both ends that are not in contact with each other. A so-called thermal crown (blister) is formed. Therefore, in the steel strip 1, a component force for moving the steel strips 1 on both ends is generated in the central portion of the hearth roll 10, and a buckling (commonly called a cooling buckle 9, a so-called wrinkle) is generated in the steel strip 1. (See FIG. 8) In the worst case, it is impossible to pass the plate.

Therefore, conventionally, a pair of opposed seal rolls 13 for reducing the area of the slit-shaped through hole 6 of the partition wall 5 are provided to suppress the inflow of the injection gas into the roll chamber 14. Then, the respective regions are set to different temperature conditions and the crown of the hearth roll 10 is suppressed (see FIGS. 4 and 5). Also, the actual Kaihei 5-69152
The publication proposes to provide exactly the same pair of seal rolls 13 at the inlet and outlet of the cooling zone in order to prevent the meandering of the steel strip 1 and the generation of the cooling buckle 9 due to the change of the set temperature of the heating zone. are doing. Such a countermeasure is sufficient if the steel strip 1 can be completely clamped, but the steel strip 1 has a thick welded portion where the preceding steel strip and the trailing steel strip are welded and a portion where thermal deformation has occurred. When the part of (1) passes through the seal roll 13, the roll is often scratched, and is often transferred to the steel strip 1 passing thereafter or wrinkles are generated. Therefore, it is necessary that the facing seal rolls 13 face each other in consideration of the roll gap equal to or more than the plate thickness so that the facing seal rolls 13 do not come into contact with the steel strip 1, and the cooling gas near the surface of the steel strips is heated by the hearth roll 10.
The temperature of the cooling gas could not be controlled accurately, and the cooling gas flow rate could not be increased.

Further, Japanese Utility Model Laid-Open No. 4-69447 discloses that
In order to overcome the above-mentioned problems, the slit-shaped through hole 6 of the partition wall 5 is sandwiched, and two opposing seal rolls 13 are provided on the upstream and downstream sides.
Disclosed is a technique in which one of the opposing seal rolls 13 is provided in pairs and one of the opposing seal rolls 13 is brought into contact with the surface of the steel strip to ensure a perfect gas seal. Certainly, this technique can be expected to have a considerable effect when focusing on only the cross-sectional direction of the seal roll 13. However, in the seal portion, the sealing property in the width direction of the seal roll is also important, and in this respect, the sealing effect of this technique was insufficient. That is, as shown in FIG. 9, there is a drawback that the cooling gas leaks at both ends of the seal rolls 2 and 3.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention is a continuous annealing furnace capable of significantly reducing the amount of injection gas discharged from a so-called plenum chamber into the hearth roll side in the gas injection cooling zone as compared with the conventional case. It is an object of the present invention to provide a sealing device.

[0007]

In order to achieve the above-mentioned object, the inventor diligently studied the flow of the injection gas passing through the slit-shaped through hole 6 of the partition wall 5 and directed the injection gas to the hearth roll 10 side. We found the conditions to prevent the outflow of water. An example thereof is shown in FIG. This is an injection speed of 100 m / se
The flow of the cooling gas 7 sprayed on the steel strip 1 in c is analyzed by the turbulent flow model, and the arrows indicate the direction and the magnitude of the flow of the cooling gas 7. This FIG.
Further, when the two seal rolls 2 and 3 are arranged in zigzag by contacting one side of the steel strip 1 respectively, the cooling gas 7 is blocked by the rolls 2 and 3 to change the flow direction, and the position of these rolls is changed. It has been known that by appropriately adjusting the distance to the partition wall 5, the outflow amount from the slit-shaped through hole 6 of the partition wall 5 can be considerably suppressed. Therefore, the present invention is
It embodies the results of this research, and supplies steel strips between opposing nozzle groups that inject cooling gas and / or between the opposing nozzle groups.
Alternatively, the hearth roll to be extracted, the installation position of the opposing nozzle group and the hearth roll are divided into upper and lower parts, and a partition wall having a slit-shaped through hole through which a steel strip passes, and in the vicinity of the slit-shaped through hole, are jetted. A seal roll for preventing the cooling gas from flowing out to the hearth roll side, and in a cooling zone of a continuous annealing furnace consisting of a furnace body surrounding the whole, the seal roll is on the side of the opposing nozzle group, and of the steel strip. This is a cooling zone for a continuous annealing furnace, which is arranged in a staggered pattern on the upper and lower sides so that only one side contacts each side separately. Therefore, the two rolls that come into contact with the steel strip are effectively arranged so that the steel plate is sandwiched between them, and the gap between the steel strip and the roll is eliminated, so that the outflow of cooling gas can be further prevented compared to the conventional cooling zone. Become.

Further, in the present invention, the above-mentioned seal roll is
Since the relation of the following formula is satisfied, the distance between the opposing nozzle group seal roll and the partition wall becomes large, and the spray gas travels in the roll width direction and enters the area on the hearth roll side from the plate-shaped through hole. Can also be prevented. L / (D-d) ≧ 3 (1) where d: seal roll diameter in contact with steel strip, D: center distance between upper and lower seal rolls, L: opposite nozzle group side seal roll center and the partition Distance to inner wall

[0009]

1 and 2 are examples of longitudinal sectional views showing a cooling zone of a continuous annealing furnace according to the present invention only on the lower side and on the upper side and the lower side. As described above, since the seal rolls 2 and 3 that come into contact with each other one by one are arranged in a staggered manner on the steel strip 1 moving upward between the plenum chambers 12, the cooling gas 7 injected from the nozzle 4 is directed to the hearth roll 10 side. Outflow is suppressed. Then, in the diameter d of the seal rolls 2 and 3 in contact with the steel strip 1, the vertical distance D between the centers of the seal rolls 2 and 3, and the distance L between the center of the roll 2 and the partition wall 5, d and Since D is determined by the device design, the condition that the cooling gas 7 does not flow out from the slit-shaped through hole 6 of the partition wall 5 as much as possible was determined in relation to the injection speed of the cooling gas 7. An example of the result is an injection speed of 100 m / se
The case of c is shown in FIG. According to FIG. 3, the cooling gas 7 from the injection nozzle 4 passes through the through hole 6 and the hearth roll 1
It was found that there is a certain relationship between the amount of entry into the vicinity of 0 and L / (D-d). That is, if the distance L between the seal roll 2 on the nozzle 4 side and the partition wall is 3 times or more (D-d) (dimensionless distance), the amount of inflow of the cooling gas 7 could be minimized. The formula (1) is derived when the cooling gas injection speed is 100 m / sec, but since the maximum flow velocity is 100 m / sec in a practical cooling zone, the formula (1) is satisfied. If this is done, good results can be obtained even with an injection speed lower than this. Further, FIGS. 4 and 5 show a conventional cooling zone. By comparing this cooling zone and the cooling zone according to the present invention, the inflow amount of the cooling gas 7 is compared and FIG.
Shown in As shown in FIG. 6, in the cooling zone according to the present invention, the amount of penetration of the cooling gas 7 was reduced to 13% of that in the case of using the conventional cooling zone. In addition, the measurement of the penetration amount of the cooling gas 7 is a calculated value based on the heat balance. 1 and 2 show the case where the cooling zone is only on the lower side and on both the upper side and the lower side, the present invention also includes the case where only the upper side, that is, the steel strip extraction side is targeted. .

[0010]

As described above, according to the present invention, it is possible to provide a cooling zone of a continuous annealing furnace capable of significantly reducing the amount of cooling gas injected from a nozzle of a so-called plenum chamber into the hearth roll side as compared with the conventional case. I was able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing only a lower side of a cooling zone of a continuous annealing furnace according to the present invention.

FIG. 2 is a vertical cross-sectional view showing the cooling zones of the continuous annealing furnace according to the present invention both up and down.

FIG. 3 is a graph showing a relationship between an amount of injected gas and L / (D−d).

FIG. 4 is a vertical cross-sectional view showing only a lower side of a cooling zone provided with a conventional facing seal roll.

FIG. 5 is a vertical cross-sectional view showing a cooling zone provided with a conventional facing seal roll both in the vertical direction.

FIG. 6 is a bar graph comparing the invasion amount of ejected gas between the conventional device and the device according to the present invention.

FIG. 7 is a view showing a cooling zone not provided with a conventional seal roll.

FIG. 8 is a view showing a cooling buckle generated in a steel strip.

9A and 9B are diagrams showing a flow of a jet gas flowing from both ends of a steel strip to a hearth roll side, wherein FIG. 9A is a perspective view and FIG. 9B is a front view.

FIG. 10 is a diagram showing an example of analysis of a flow of a jet gas in a cooling zone.

[Explanation of symbols]

 1 Steel Strip 2 Upper Seal Roll 3 Lower Seal Roll 4 Injection Nozzle 5 Partition Wall 6 Slit Through Hole 7 Cooling Gas 8 Steel Strip Traveling Direction 9 Cooling Buckle 10 Hearth Roll 11 Furnace Wall 12 Plenum Chamber 13 Opposed Seal Roll 14 Roll Chamber

Front page continuation (72) Inventor, Makoto Suzuki, 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Steel Works, Ltd. (72) Inventor, Yasutaka Uchida, 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Steel Works (72 ) Inventor Naoto Ueno 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Chiba Works

Claims (2)

[Claims] 1. A counter nozzle group for injecting a cooling gas, a hearth roll for supplying and / or withdrawing a steel strip between the counter nozzle groups, and an installation position of the counter nozzle group and a hearth roll are divided into upper and lower parts. A partition wall having a slit-shaped through hole through which the belt passes, a seal roll which is in the vicinity of the slit-shaped through hole and prevents the injected cooling gas from flowing out to the hearth roll side, and a furnace body surrounding the whole In a cooling zone of a continuous annealing furnace consisting of, the seal rolls are arranged in a zigzag pattern on the opposite nozzle group side and on both sides of the steel strip so that only one side is in contact with each other separately. Cooling zone of continuous annealing furnace. 2. The cooling zone of a continuous annealing furnace according to claim 1, wherein the seal roll satisfies the relationship of the following equation. L / (D-d) ≧ 3 (1) where d: seal roll diameter in contact with steel strip, D: center distance between upper and lower seal rolls, L: opposite nozzle group side seal roll center and the partition Distance to inner wall