JPH02259025A - Continuous annealing furnace - Google Patents

Abstract

PURPOSE:To prevent atmospheric gas at each zone in a continuous annealing furnace from mutually mixing by arranging upper and lower wind boxes facing to pass line at connecting parts of plural zones and blowing the atmospheric gas at adjacent zones on the pass line. CONSTITUTION:In plural zones in the continuous annealing furnace, e.g. at the upper and lower parts of the connecting part of a soaking zone 1 with a cooling zone 2, the wind boxes 3 facing to the pass line are arranged. The wind box 3 is divided into two chambers 3a, 3b at front and rear parts with the parting plate 4 and slit nozzles 5a, 5b are arranged in the chambers 3a, 3b. When a strip S passes through between the wind boxes 3, 3, the atmospheric gas in the soaking zone 1 is injected from the slit nozzles 5a at the soaking zone 1 side through a blower 7a. Further, the atmospheric gas in the cooling zone 2 is injected from the slit nozzles 5b at the cooling zone 2 side. By this method, the mixing ratio of the atmospheric gases at each zone can be suppressed to less than few %.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a continuous annealing furnace, and particularly to a continuous annealing furnace in which the inside of the furnace can be divided into a plurality of zones and each zone can be maintained at a unique atmosphere composition and temperature.

<Prior art> Continuous annealing furnaces for steel strips, such as strips, generally have a heating zone, a soaking zone, and a cooling zone, each of which is maintained at desired atmospheric composition and temperature conditions. Continuous annealing of the strip is carried out.

When continuously annealing a strip, it is necessary to adjust the atmosphere gas in each zone of the annealing furnace, such as the decarburizing atmosphere zone and weakly reducing atmosphere zone, or the soaking zone and cooling zone, to the desired atmosphere composition and temperature. Mixing of gases shall be prevented.

Conventionally, various proposals have been made to prevent mixing of atmospheric gases in each zone in a continuous annealing furnace. For example, Jikko 63
Publication No. 19316 discloses that sealing materials made of a soft material are provided at intervals on the soil wall of the throat provided at the connecting portion of each zone, and on the other hand, the soft sealing materials are provided on protrusions provided at intervals on the lower wall of the throat. A small chamber is disclosed in which a small chamber is formed by covering a sealing material made of the above and bringing a portion of the upper and lower sealing materials into contact with each other.

In this conventional technology, the atmospheric gas in the front and rear zones is separated by making the gas pressure in the small chamber lower than the atmospheric gas pressure in the front and rear zones. As a result, the sealing material made of soft material wears out in a short period of time, making it impossible to seal the top and bottom of the strip.

For this reason, there is a problem that the atmospheric gas in the front and rear zones increases and mixing of the atmospheric gas cannot be prevented.

Furthermore, in Japanese Patent Application Laid-Open No. 55-34645, a gas injection header is provided at the connection part of each band with a strip passage in between,
A device is disclosed in which inert gas is injected from the header to prevent atmospheric gases from mixing in the front and rear zones.

However, this conventional technique not only requires a large amount of inert gas, but also has the problem that it is difficult to adjust the composition of the atmospheric gas because the injected inert gas flows into the front and rear zones.

<Problems to be Solved by the Invention> The present invention has been made in order to solve the problems of the prior art described above, and is to reliably prevent atmospheric gases in each zone of a continuous annealing furnace from mixing with each other. The purpose of the present invention is to provide a continuous annealing furnace that can perform continuous annealing.

<Means for Solving the Problems> A continuous annealing furnace according to the present invention that achieves the above object is a continuous annealing furnace in which the inside of the furnace is divided into a plurality of zones, and a wind box is provided as a pass line at the connection part of the plurality of zones. The wind box is arranged vertically facing each other, and the wind box is partitioned into two chambers, front and back, in the direction of the pass line, and nozzles communicating with each of the chambers are placed close to the surface of the wind box facing the pass line, corresponding to each of the above chambers. The front and rear chambers of each of the wind boxes are connected to the zones where each of the chambers is adjacent to each other with gas supply piping, and blowers are installed in the middle of each of the piping, and air blowers are installed in the front and rear of each of the wind boxes. It is characterized in that the atmospheric gas in each adjacent zone is supplied through the blower, and the atmospheric gas is blown onto the pass line from the nozzle.

In addition, in the present invention, instead of dividing each wind box into two chambers, front and back, nozzles are provided near the front and rear of the surface of the wind box that faces the pass line, and the nozzles are communicated with one of the nozzles, so that the outlet side inside the wind box is connected to the nozzle. It is also possible to arrange a nozzle header, a heat exchanger tube, and an inlet side distribution pipe, and make the other nozzle communicate with the wind box.

<Function> As described above, the present invention provides a wind box at the connection part of each zone in a continuous annealing furnace facing the pass line from above and below, and two wind boxes are provided adjacent to each other in the front and rear of the pass line direction of each wind box. Since the air is ejected from each jet nozzle to the steel strip on the pass line, static pressure is formed between the wind box between the two front and rear jet nozzles and the steel strip, so atmospheric gas is released at the connection of each zone. Can be reliably separated.

Furthermore, since each of the two front and rear jet nozzles uses the adjacent atmospheric gas, there is no adverse effect on the atmospheric gas composition in each zone.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a soaking zone and 2 is a cooling zone. 3 is a wind box, and the wind box 3 is disposed above and below the connection between the soaking zone 1 and the cooling zone 2, facing the pass line. The upper and lower wind boxes 3.3 are each partitioned into two front and rear chambers, 3a and 3b, by a partition plate 4 in the direction of the pass line, and the front and rear chambers 3a and 3b of the upper and lower wind boxes 3.3 face the pass line. Slit nozzles 5a, 5 are arranged adjacent to each other on the surface.
b is a provision. In the drawing, it is a slit nozzle 5a.

Although the direction of the strip 5b is shown perpendicular to the strip S, it may be inclined at an appropriate angle.

The chambers 3a of the upper and lower wind boxes 3 and the soaking zone 1 are connected by a pipe 6a, and a blower 7a is installed in the middle of the pipe 6a. Further, the chamber 3b on the side of the cooling zone 2 and the cooling zone 2 are connected by a pipe 6b, and a blower 7b is installed in the middle of the pipe 6b. Note that 8a and 8b indicate air volume distributors.

Reference numeral 9 denotes a cylinder attached to the support frame 10, and the cylinder 9 allows the upper wind pipe 3 to move up and down. 1
Reference numeral 1 denotes a plate recognition device, which is designed to observe the plate shape of the strip S in the soaking zone 1.

Next, to explain the operation, when performing continuous annealing in a continuous annealing furnace, a predetermined atmospheric gas is supplied to soaking zone 1 and cooling zone 2, respectively.For example, soaking zone 1 is supplied with a hydrogen gas atmosphere, and cooling Zone 2 is placed in a nitrogen gas atmosphere.

By the way, the strip S passes between the upper and lower wind boxes 3, 3 from the soaking zone 1 to the cooling zone 2, as shown by the arrow, and then passes through the roller 13.
When traveling above the soaking zone 1, the atmospheric gas in the soaking zone 1 is injected from the slit nozzle 5a on the soaking zone 1 side, and the cooling zone 2
Atmospheric gas within the cooling zone 2 is injected from the side slit nozzle 5b.

That is, the atmospheric gas in the soaking zone 1 is extracted by the blower 7a installed in the middle of the pipe 6a, and the atmospheric gas is extracted from the upper and lower wind boxes 3.
, 3 and then sprayed onto the surface of the strip S from the slit nozzle 5a. Further, the atmospheric gas in the cooling zone 2 is extracted by a blower 7b installed in the middle of the pipe 6b, is forced into the chamber 3b of the upper and lower wind pipes 3, 3, and is then injected onto the back surface of the strip S from the slit nozzle 5b.

At this time, the front and rear adjacent slit nozzles 5a.

By adjusting and balancing the air volume from the slit nozzles 5a and 5b, a static pressure state is maintained between the front surface of the wind box 3 and the strip 3 between the slit nozzles 5a and 5b.
and each atmospheric gas in the cooling zone 2 are separated. In this case, in order to stably maintain the static pressure state, the slit nozzles 5a, 5
It is preferable to make the distance between b and strip S as close as possible so that the distance between them is small.

On the other hand, the atmospheric gas in the soaking zone 1 injected from the slit nozzle 5a is circulated to the soaking zone 1 as shown by the solid arrow,
Further, the atmospheric gas in the cooling zone 2 injected from the slit nozzle 5b is circulated to the cooling zone 2 as shown by the solid arrow.

Therefore, each atmospheric gas in the soaking zone 1 and the cooling zone 2 is stably maintained at a predetermined composition.

In addition, the board shape of the strip S in the soaking zone 1 is observed through the viewing window 12 by the board shape recognition device 11, and defects in the board shape such as bulges and bulges of the strip S are found, and the defective board shape portions are passed through. Only when the cylinder 9 is activated, the upper wind box 3 is retracted upward, and at the same time, the slit nozzle 5 is activated.
'Increase the injection amounts of a and 5b to ensure separation.

FIG. 2 shows another embodiment of the present invention. In FIG. 2, unlike the one in FIG. 1, instead of dividing the upper and lower wind boxes 33 into two front and rear chambers, the Inlet side distribution pipe 2
0 and the outlet nozzle header 21 are arranged, and the inlet side distribution pipe 2
A heat transfer tube 22 connecting the wind pipe 0 and the outlet nozzle header 21 is provided to partition the inside of the wind pipes 3, 3. A plurality of heat transfer tubes 22 are arranged in the width direction of the wind tube 3. 23 is a heat exchanger tube 22
24 indicates a gas guide plate.

The inlet side distribution pipes 20.20 of the upper and lower wind boxes 3 and the soaking zone 1 are connected by a pipe 6a, and the nozzle header 21 communicates with the slit nozzle 5a. The outer surface of the wind box 3 and the cooling zone 2 are connected by a pipe 6b, and a slit nozzle 5b is provided on the surface of the wind box 3 facing the pass line. The rest of the configuration is the same as that of the embodiment shown in FIG. 1, so a description thereof will be omitted.

Next, to explain the operation, the atmospheric gas in the soaking zone 1 is guided to the distribution pipe 20 via the pipe 6a, and the heat transfer pipe 22,
It passes through the nozzle header 21 and is injected onto the surface of the strip S from the slit nozzle 5a. Further, the atmospheric gas in the cooling zone 2 is guided into the wind box 3 via the pipe 6b, and without being guided by the gas guide plate 24, passes through the wind box 3 and is injected from the slit nozzle 5b.

At this time, the atmospheric gas (high temperature) in the soaking zone 1 passing through the heat transfer tube 22 and the atmospheric gas (low temperature) passing through the wind box 3 in the cooling zone 2 undergo heat exchange, and then the slit nozzles 5a, 5b are respectively is sprayed from.

Therefore, the temperature of the gas injected from the slit nozzle 5a (
T, ) is lower than the atmospheric gas temperature (T, ) in soaking zone 1,
Furthermore, the temperature of the gas injected from the slit nozzle 5b (T,
) becomes higher than the atmospheric gas temperature (Tc) of the cooling zone 2.

The height relationship of these gas temperatures is T h :> T I>
Since T z :> T c, from soaking zone l to wind box 3
, 3 and guided into the cooling zone 2.
The sudden drop in temperature is alleviated, and the occurrence of plate distortion can be prevented. Note that the adjacent slit nozzles 5a and 5b
The separation effect between the soaking zone 1 and the cooling zone 2 is achieved in the same manner as described for the embodiment of FIG. 1 above.

Figure 3 shows the temperature change of the strip led from the soaking zone through the wind box to the cooling zone when heat is exchanged (corresponding to the embodiment shown in Figure 1) and when heat is exchanged (corresponding to the embodiment shown in Figure 2). This is a schematic comparison between the two.

As shown in Figure 3, when there is no heat exchange, the difference in temperature of the fumes from the adjacent front and rear slit nozzles is large, so the strip is rapidly cooled as shown by the dotted line, whereas when heat exchange is done, the fumes are rapidly cooled. Since the temperature difference is small, the temperature drop is alleviated, and the occurrence of plate distortion can be prevented.

From the above results, the one shown in Fig. 1 is more suitable for the connection part where the temperature difference is small among the multiple zones of a continuous annealing furnace, and
The one shown in the figure is suitable for connections with large temperature differences.

<Effects of the Invention> As explained above, according to the present invention, in a continuous annealing furnace in which the inside of the furnace is divided into a plurality of zones, atmospheric gases having 11 different compositions and temperatures are reliably separated at the connection part, and the mixing ratio of the atmospheric gases is reduced. It is now possible to suppress the amount of carbon dioxide to a few percent or less, and the effect is significant.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view of a continuous annealing furnace according to an embodiment of the present invention, FIG. 2 is a partial vertical cross-sectional view of a continuous annealing furnace according to another embodiment of the present invention, and FIG. It is a graph which schematically shows the temperature change situation of the strip in a boundary part. DESCRIPTION OF SYMBOLS 1... Soaking zone, 3... Wind box, 5... Slit nozzle, 7... Air blower, 9... Cylinder, 12... Peephole, 20... Inlet side distribution pipe, 22 ...heat exchanger tube, 24...gust guide plate. 2... Cooling zone, 4... Partition plate, 6... Piping, 8... Air volume distributor, 11... Plate shape recognition device, 13... Roller, 21... Outlet side Nozzle header, 23... heat transfer fin,

Claims (1)

[Claims] 1. A continuous annealing furnace in which the inside of the furnace is divided into a plurality of zones,
A wind box is arranged above and below the connection part of the plurality of bands facing the pass line, and the wind box is partitioned into two rooms, front and back, in the direction of the pass line, and each of the above wind boxes is placed on the surface facing the pass line. Nozzles communicating with each chamber are arranged in close proximity to each other, and the front and rear chambers of each of the above-mentioned wind boxes and the zone where each of the above-mentioned chambers is adjacent are connected by gas supply piping, and the nozzles are connected in the middle of each of the above piping. A blower is installed, and atmospheric gas in adjacent zones is supplied to each of the front and rear chambers of the wind box through the blower, and the atmospheric gas is blown onto the pass line from the nozzle. Continuous annealing furnace with special features. 2. Providing nozzles close to the front and rear of the surface of the wind box facing the pass line, and disposing an outlet nozzle header, a heat exchanger tube, and an inlet distribution pipe in the wind box so as to communicate with one of the nozzles; Claim 1, wherein the other nozzle is communicated with the wind box.
Continuous annealing furnace as described.