JPH04341526A - Water cooling device for continuous annealing furnace - Google Patents

Abstract

PURPOSE:To accurately and easily execute temp. control by the cooling water in a water cooling device having the cooling water vessels divided into plural steps by reducing cooling water quantity carried from the front step of a cooling water vessel to the rear step of a cooling water vessel in accordance with a steel strip. CONSTITUTION:This device is the water cooling device on the outlet side of a continuous annealing furnace for steel strip, draining rolls 1a, 1b are arranged on a steel strip passage between the cooling water vessels 2, 3 divided into plural steps and also the projecting part at upper part of the partitioning plate 5 between each vessel is inclined to the rear step side.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention reduces the amount of cooling water brought into the cooling water tank in the latter stage by steel strips from the former stage in a water cooling system having a cooling water tank divided into multiple stages, thereby making temperature control more accurate. This paper proposes a water cooling system for a continuous annealing furnace for steel strips.

[0002] In recent years, a method of continuously performing continuous annealing and skin-pass rolling has become popular in the manufacturing process of steel strips. It is important to reduce the fluctuations in the steel strip temperature on the entry side. Therefore, it is desired to accurately control the temperature of the steel strip after cooling with a cooling device on the outlet side of the continuous annealing furnace.

0003

[Prior Art] Regarding the cooling of steel strips in a continuous annealing line, for example, Japanese Patent Publication No. 11931/1983 describes a method and apparatus for cooling steel strips, and Japanese Patent Publication No. 25060/1989 describes a method of cooling steel strips. , a method using a plurality of cooling water tanks is proposed and disclosed. The advantages of using a plurality of cooling water tanks are: (1) By sending cooling water from the latter stage of the cooling water tank to the first stage, the heat recovery rate of the cooling wastewater that has reached a higher temperature is improved, and the equipment can be simplified. ■ By controlling the cooling water temperature of each cooling water tank by combining it into an appropriate temperature range, the temperature of the steel strip at the exit side of the cooling water tank can be controlled more accurately, and it is possible to operate at higher speeds. etc.

[0004] As described above, by using a plurality of cooling water tanks, not only can cooling be performed at high speed operation, but also the accuracy of the steel plate temperature after water cooling can be improved, and the process of consecutively performing the above-mentioned continuous annealing and skin pass rolling can be improved. It has become possible to keep the range of fluctuation in the temperature of the steel strip at the entrance of the skin pass rolling mill small, which is a problem.

However, in this case, the water temperature of each cooling water tank is controlled by a system in which cooling water is supplied from the latter stage of the cooling water tank to the previous stage. A flow opposite to the above occurs, in which the water is brought into the cooling water tank, and the amount of water increases as the conveyance speed of the steel strip increases, making it difficult to control the water temperature in each cooling water tank, and the water temperature control device becomes difficult to control. The problem was that it was large-scale and expensive.

[0006]

[Problems to be Solved by the Invention] This invention aims to advantageously solve the above-mentioned problems, and provides a steel strip that can reduce the amount of cooling water brought into the cooling water tank from the front stage to the rear stage by the steel strip. The purpose of the present invention is to propose a water cooling device, thereby making it possible to more accurately and easily control the temperature of cooling water.

[0007]

[Means for Solving the Problems] As a result of various experiments, the present invention has found that in order to remove the water film on the surface of the steel strip during conveyance,
This is because it was found that pressing the drain roll against the steel plate is the most effective and simplest method, and can also be used for high-speed operation.

In other words, the gist is a water cooling system that has a cooling water tank divided into multiple stages on the exit side of a continuous annealing furnace, and performs final cooling by sequentially passing the continuously annealed steel strip through the cooling water tank of each stage. A water cooling device for a continuous annealing furnace is characterized in that a drain roll is provided in the steel strip passage between each cooling water tank.

[0009]

[Operation] The operation of the present invention will be explained using FIG. 1 as an example. FIG. 1 shows one example of the device of the present invention, and is a longitudinal cross-sectional view of a water cooling device (two-tank type) consisting of two cooling water tanks.

In FIG. 1, reference numerals 1a and 1b are a pair of draining rolls, and these draining rolls 1a and 1b are arranged in a passageway of a steel strip 7 between a cooling water tank 2 at the front stage and a cooling water tank 3 at the rear stage. , one draining roll 1a is pressed against the other draining roll 1b with a steel strip 7 in between by a pressing cylinder 4.

[0011] By using such a water cooling device,
Even if the cooling water is taken out from the cooling water tank 2 at the front stage by the steel strip 7, most of the water film on the surface of the steel strip 7 is removed by the draining rolls 1a and 1b, so that the cooling water is not carried out to the cooling water tank 3 at the rear stage. The amount brought in will be significantly reduced.

Furthermore, the partition plate 5 between the cooling water tank 2 at the front stage and the cooling water tank 3 at the rear stage has its upwardly protruding portion inclined toward the cooling water tank 3 at the rear stage, thereby preventing the steel strip and the draining roll 1 from being separated.
It receives water droplets falling from a and 1b, and prevents these water droplets from entering the cooling water tank 3 at the subsequent stage.

In this way, the amount of cooling water brought in by the steel strip 7 from the cooling water tank 2 at the front stage to the cooling water tank 3 at the rear stage is significantly reduced, making it easy to control the temperature of the cooling water and improving its accuracy. is improved, and the temperature fluctuation range of the steel strip 7 after cooling can be reduced.

[0014]

[Embodiment] An embodiment of the present invention will be described using the two-tank type water cooling device shown in FIG. 1 described above. In FIG. 1, the steel strip 7 that has exited the continuous annealing furnace is immersed in the cooling water tank 2 via the sink roll 6 in the cooling water tank 2 at the front stage, then passes between the drain rolls 1a and 1b, and then passes through the cooling water tank at the rear stage. It is immersed in the cooling water tank 3 via the sink roll 6 in the cooling water tank 3, and then continuously transported outside the system.

In the above device, the draining rolls 1a and 1b are both rolls with rubber lining (Hypalon), and both are driven, and the pressing cylinder 4 can be operated by electric, hydraulic, or pneumatic methods. Any of these could be used, but in this case, an air cylinder was used. In addition,
The draining rolls 1a and 1b can be opened when heat buckling occurs.

On the other hand, the pressing pressure between the draining rolls 1a and 1b when threading the steel strip 7 is linear pressure (pressing pressure/
Roll barrel length), if it is less than 6.5 kgf/cm, drainage will be insufficient, and if it exceeds 12 kgf/cm, the steel strip will break, so the linear pressure should be set to 6.5 to 6.5 kgf/cm.
It was adjusted to fall within the range of 12 kgf/cm.

[0017] As a result of threading the plate at a conveying speed of 1000 m/min, if no draining roll was used,
The thickness of the cooling water film on the steel strip 7 was 800 μm, but when the drain rolls 1a and 1b are used, the film thickness becomes 10 μm.
m, and the amount of water carried from the front cooling water tank 2 to the rear cooling water tank 3 could be significantly reduced to about 1/80.

[0018] Therefore, the amount of overflow from the downstream cooling water tank is reduced, and it is also possible to greatly simplify the overflow equipment (piping system and pump capacity). Also, by using this device, fluctuations in water temperature between the front and rear stages could be reduced to about 5 to 10 times less than when not in use.

Here, FIG. 2 shows a pair of draining rolls 1a.
In FIG. 2, the draining roll 1a has its center 0a between the point A where the steel strip 7 first contacts the draining roll 1b and the draining roll 1.
Place it on a straight line passing through the center 0b of the draining roll 1b within the range of the angle α (shown) between a straight line passing through the center 0b of the draining roll 1b and a straight line passing through the center 0b of the draining roll 1b perpendicular to the horizontal direction. That's fine.

The draining roll 1b shown in FIGS. 1 and 2 also serves as a turn roll, but there are a pair of drain rolls in the steel strip passage from when the steel strip exits the cooling water tank until it reaches the turn roll. There is no harm in installing a drain roll,

00
[21] Furthermore, the pressing cylinder may be attached not only to one of the pair of draining rolls but also to both of them.

[0022]

Effects of the Invention This invention provides a drain roll in the steel strip passageway between cooling water tanks divided into multiple stages to remove a water film on the surface of the steel strip. This greatly reduces the amount of cooling water brought into the steel strip by the steel strip.This makes it possible to accurately and easily control the water temperature in each cooling water tank, making continuous annealing and adjustment possible. It is suitable for use in a cooling device for continuous annealing when continuous rolling is performed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a water cooling device consisting of two cooling water tanks, showing one example of the present invention.

FIG. 2 is a longitudinal sectional view showing the positional relationship between a pair of draining rolls 1a and 1b.

[Explanation of symbols]

1a Drain roll 1b Draining roll 2. Front stage cooling water tank 3　Late stage cooling water tank 4 Pressing cylinder 5 Partition board 6. Think roll 7 Steel strip

Claims (1)

[Claims] [Claim 1] A water cooling system having a cooling water tank divided into multiple stages on the exit side of a continuous annealing furnace, and in which a continuously annealed steel strip is sequentially passed through the cooling water tank of each stage to perform final cooling. A water cooling device for a continuous annealing furnace, characterized in that a drain roll is provided in a steel strip passage between cooling water tanks.