JPS6210224A - Cooling apparatus for steel strip - Google Patents

Abstract

PURPOSE:To suppress contact of a steel strip with a nozzle, by providing plural ribs elongated in the steel strip running direction protrudedly and parallelly in the steel strip width direction, and allowing rib top end height to coincide with nozzle top end. CONSTITUTION:The heated steel strip 1 is run in the arrow direction, cooling gas is supplied to headers 3a, 3b from blowers 2a, 2b and jetted perpendicularly to the strip 1 from straight nozzles 4a, 4b. Simultaneously the sheet 1 is cooled by cooling gas from gas cushion nozzles 5a, 5b composed of slit nozzles 8a, 8b slanted to steel strip surface and pressure receiving sheets 6a, 6b. Thereat, the plural ribs 7a, 7b elongated in the running direction of the strip 1 are provided protrudedly and parallelly in the strip 1 width direction to the sheets 6a, 6b, and the top end height is allowed to coincide with top ends of the nozzles 8a, 8b. In this way, labyrinth effect is exhibited, contacts of the strip 1 with the nozzles 3a, 3b, 8a, 8b are suppressed, cooling capacity s increased and equipment can be made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to improvements in cooling devices for steel strips in continuous annealing equipment, continuous heat treatment lines, and the like.

<Prior Art> As a method of cooling a hot steel strip in a continuous annealing facility or a continuous heat treatment line for steel strip, a method is known in which a running steel strip is cooled by jetting gas from a slit nozzle. This kind of gas jet type cooling device is shown in FIG. 4, in which a cooling gas (for example, He
-Ne mixed gas]? The steel strip 1 was cooled by being ejected from the gas jet nozzle of the steel strip 1 through the heaters 3a and 3bk. As shown in Fig. 4, the gas jet nozzles of the headers 3a and 3b are straight nozzles 4a and 4b, which face perpendicularly to the steel strip surface, and two slit nozzles with their jet nozzles inclined inward toward the steel strip surface. 8a, 8a: 8b, 8b and these slit nozzles 3
a, 3a: 8b, 8bl'! 1'! r flat plate 6a, 6bT
Gas cushion type nozzles (hereinafter referred to as gas cushion nozzles) 5a and 5b with a closing structure were used.

Among the cooling nozzles described above, straight nozzles 4a, 4
The main role of b is cooling, and although the cooling capacity of the gas cushion nozzle is slightly lower than that of a straight nozzle, it is a slit nozzle and a flat plate placed between the slit nozzles (hereinafter referred to as the "pressure receiving plate"). A quasi-closed space is formed for the gas flow ejected in the area surrounded by the steel strip surface, a gas reverse flow is formed, and the entire space can be maintained at a high pressure, deforming and the nine steel strips traveling and being transported. When the steel strip is bent or approaches the nozzle due to tension fluctuations, the steel strip has the ability to be pushed back (hereinafter referred to as ``gas cushion function''). This function is particularly effective when the inclination angle θ of the ejection port of the slit nozzle is 30 to 60°.

<The far point that the invention is trying to solve> In the case of a steel strip cooling device similar to this type of gas jet,
If the steel strip approaches the gas cushion nozzle in parallel,
Even the conventional gas cushion nozzle is effective in preventing contact between the gas cushion nozzle and the steel strip. But in reality,
When the steel strip approaches the nozzle in the width direction, the steel strip approaches the nozzle in a round shape with a convex or concave central part, so the above-mentioned effect cannot be achieved, and sometimes the steel strip and nozzle It has the disadvantage that the steel strip will be scratched when it comes into contact with the steel strip. This is because when the steel strip approaches, the gas in the gas cushion nozzle collar does not reverse to the running direction of the plate and leaks in the width direction of the steel strip, resulting in a repulsive force against the steel strip (gas cushion This is due to the loss of the effect.

The present invention is designed to reverse all of the above drawbacks by reversing the flow of gas from the gas cushion nozzle in the running direction of the plate no matter which nib shape the steel strip approaches the nozzle.

Ninth Means for Solving the Problems> Ninth Means for Solving the Problems Above Ninthly, the steel strip cooling device according to the present invention is provided so as to face each other on both sides of the running steel strip. In a cooling device for a steel strip, which has two slit nozzles whose ejection ports are inclined inward to each other, and a gas cushion nozzle arranged between these slit nozzles, the steel strip runs on a flat plate between the slit nozzles. The present invention is characterized in that a plurality of ribs extending in the width direction of the steel strip and arranged in parallel in the width direction of the steel strip are arranged so that the height of the tip thereof matches the tip of the gas cushion nozzle.

For Kusaku In this process, the pressure plate is placed between the slit nozzles.

The height of the tips of the ribs, which extend in the running direction of the steel strip and are arranged in parallel in the width direction of the steel strip, is set to match the height of the gas cushion nozzle, so that the steel strip does not touch the nozzle. No matter how they approach, the distance between the rib and the steel strip becomes close, so the gas leaking from the width direction of the steel strip will leak due to the so-called labyrinth effect due to the large fluid resistance. υ is difficult, so the gas has no choice but to flow in the opposite direction.゛At this ninth point, the original gas cushion effect can be demonstrated.

Embodiment An embodiment adopted in a gas jet cooling zone in a continuous annealing furnace for cold-rolled steel sheets will be described below with reference to one drawing.

Figure 1 is a side sectional view of the gas jet cooling zone, Figure 2 is
Front view of the gas cushion nozzle part in Fig. 1 (A side view),
FIG. 3 is an enlarged view of the gas cushion nozzle. In these figures, 1 is 70 mm in a continuous annealing furnace (not shown).
A steel strip 5 running in the direction of the arrow that has been heated or heated and soaked to about 0 to 800°C is rapidly cooled to about t-4crO°C with nJ of N2 mixed cold gas.

2a and 2b are) I2 N2 mixed cold gas? Round blower s 3a, 3b are headers, 4a.

4b is a normal straight type nozzle, and 5a is a normal straight type nozzle.

5b is a gas cushion nozzle, 6a and 5b are pressure receiving plates, and 7a and 7b are provided protruding from the pressure receiving plates toward the steel strip.
A large number of tj IJ plates are provided in parallel in the running direction of the board in the direction of the board surface. When looking at the 8 aJ7 gas cushion nozzle from the front, it is a slit nozzle from which gas is ejected.

As can be seen from Fig. 2, as the steel strip 1 approaches the lip, it is ejected from the slit nozzle and leaks in the width direction of the steel strip. As the flow resistance increases, leakage occurs in the width direction of the plate, and as a result, the gas has no choice but to flow in the running direction of the plate, resulting in a so-called reverse flow, making it easier for the gas cushion nozzle to exert its original gas cushion effect. . Furthermore, since a large number of such lips are arranged side by side in the width direction of the strip, the above-mentioned gas cushion effect will be exerted if the plates are brought close together between each lip, so even if the width of the steel strip changes, the nozzle The effect of making it difficult to come into contact with the person does not decrease.

Normally, the steel strip runs entirely in the center between opposing nozzles with the steel strip in between, so the original cooling effect of the nozzles is not completely lost.

Note that such an effect is not limited to a vertical path in which the steel strip runs vertically as shown in FIG. 1, but can also be achieved in a horizontal path in which the steel strip runs horizontally.

<Effects of the Invention> As is clear from the above description, the steel strip cooling device of the present invention further extends in the running direction of the steel strip on the pressure receiving plate between the slit nozzles.

In addition, multiple lips whose tips coincide with the gas cushion nozzle are protruded in parallel to the running direction of the steel strip. ■ This makes it difficult for the steel strip to come into contact with the nozzle, thereby preventing scratches on the surface of the steel strip. It never occurs.

■ Cooling capacity is increased because the distance between opposing nozzles can be brought closer to each other by sandwiching the steel strip.

■ Due to the effect of 2, the F equipment will be in contact.

[Brief explanation of drawings]

The first factor is a cross-sectional view of main parts showing a schematic configuration of an embodiment of the steel strip cooling device according to the present invention, FIG. 2 is a side view A of the gas cushion nozzle portion in FIG. Cross-sectional view of the figure,
FIG. 4 is a sectional view of a main part of a conventional steel strip cooling device. In the drawing, 1 is the steel strip, 2a and 2b are the blowers, and 3a and 3b are the header%.
4a, 4b are straight nozzles, 5a, 5b are gas cushion nozzles, 6a, 6b are flat plates (pressure receiving plates) s 7
a * 7 b is a reply, ga. 8b is a slit nozzle.

Claims (1)

[Claims] A gas cushion type nozzle consists of two slit nozzles, which are placed facing each other on both sides of a running steel strip, and whose ejection ports are inclined inward from each other on the steel strip surface, and a flat plate placed between these slit nozzles. In a steel strip cooling device having a gas cushion type nozzle, a plurality of ribs are arranged on a flat plate between slit nozzles, extending in the running direction of the steel strip and arranged in parallel in the width direction of the steel strip. A cooling device for a steel strip, characterized in that it is provided to match the tip.