JPS6338410B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sealing structure for the entrance and exit of a steel strip in an atmospheric furnace for continuously heat-treating steel strips.

(Prior art) Conventionally, after cold-rolling a steel plate, annealing heating and cooling are performed to improve workability.
If the steel plate is treated in an atmosphere containing water vapor, etc., it will be oxidized, forming an oxide film on the surface and losing its metallic luster. So-called bright annealing is performed using a gas to perform annealing without losing the metallic luster during rolling.

An example of a conventional horizontal bright annealing furnace is shown in FIG. 3, and an example of a vertical bright annealing furnace is shown in FIG. 4. The annealing furnace includes a furnace box 3 for heat-treating the rolled steel strip 5, a heating source 4 for heating the furnace box 3 to a predetermined temperature from the outside, and a furnace box 3.
There is an inlet section 1 for the steel strip 5 on the inlet side of the furnace box 3, a cooling section 6 for cooling the steel strip 5 on the outlet side of the furnace box 3, and an outlet section 2 for the steel strip 5. A conveyor roller 7 is provided inside the furnace to convey the steel strip 5, and an inlet 8 and an outlet 9 for introducing atmospheric gas into the furnace are also provided.

To explain the operation in the annealing furnace as described above,
Atmospheric gas is introduced into the furnace through the inlet 8, replaces the inside of the furnace with the atmospheric gas, and is discharged from the seals 1 and 2 to the outside of the furnace. The furnace box 3 is then heated with a heat source 4 such as electric heat or gas fuel. The steel strip 5 is fed into the furnace from the inlet 1, conveyed by conveying rollers 7, and bright annealed in the furnace box 3. The steel strip 5 is continuously conveyed by conveying rollers 7, cooled by an air-cooled or water-cooled cooler 6, and passed through the outlet section 2.
is discharged outside the furnace.

This bright annealing furnace has a seal part at the entrance part 1 and outlet part 2 to shut off outside air, and the quality of this seal part affects the amount of consumption of the atmosphere gas in the furnace, and also to prevent outside air from entering the furnace. is important. In other words, if the seal is bad, the amount of atmospheric gas consumed will increase, which will increase running costs.Also, if outside air enters the furnace and the amount of oxygen increases, the atmosphere will become oxidizing and oxides will be generated on the metal surface, reducing the luster. For products that are valued, the value of the product will be significantly reduced.

FIG. 5 is a longitudinal cross-sectional view of the seal structure of the entrance/exit portions 1 and 2, which has been commonly used in the past, and FIG. 6 is a longitudinal cross-sectional view in the steel strip traveling direction. As shown in the figure, the seal part includes an inclined plate 10 that faces both sides of the steel strip 5 at the end of the furnace box and is inclined and reduced in the direction of the entrance/exit to form an opening for the entrance and exit of the steel strip. Seal members 11a, 11b made of felt or the like are provided to hold both sides of the steel strip that enters and exits the opening, and a presser foot that holds the seal members 11a, 11b in contact with both back surfaces of the seal members 11a, 11b. Boards 12a, 12b
, adjustment bolts 13a, 13b for adjusting the holding force of the holding plates 12a, 12b, and left and right side plates 14a,
14b. There is atmospheric gas 16 inside the furnace and outside air 17 outside the furnace.
The sealing materials 11a and 11b held down by the sealing members 11a and 11b prevent the atmospheric gas 16 from leaking into the outside air 17.

(Problem to be solved by the invention) However, in an actual furnace, the sealing material 11
a, 11b have poor ventilation, so the atmospheric gas 16 in the furnace passes through the sealing materials 11a, 11b between the inclined plate 10 and the holding plates 12a, 12b, and the outside air 17.
Although a considerable amount of atmospheric gas 16 does not leak into the outside air 17 through the sealing materials 11a, 11b between the holding plates 12a, 12b and the steel strip 5, Side plate 14
It leaked into the outside air from between a and 14b, resulting in increased gas consumption, a high dew point of the atmospheric gas 16, lowering operational efficiency, and deteriorating quality.

(Means for Solving the Problems) The present invention eliminates the conventional drawbacks and problems;
The purpose is to provide an improved sealing structure for the entrance and exit of an atmosphere heating furnace.
The above object can be achieved by providing an entrance/exit seal structure for an atmosphere heating furnace as described in the claims. That is, the present invention provides a sealing structure for the entrance and exit of a steel strip in an atmospheric furnace for continuously heat-treating steel strips, in which both sides of the steel strip at the end of the furnace box are inclined and reduced in the direction of the entrance and exit. an inclined plate forming an opening for the strip to be taken in and out, a sealing material provided so as to sandwich both sides of the steel strip passing in and out of the opening, and a sealing material being held in contact with both back surfaces of the sealing material. In the steel strip entrance/exit seal structure for an atmospheric furnace having a holding plate, the inclined plate is located between both sides of the steel strip entrance/exit opening formed at both end faces of the both inclined plates and the furnace box side plate. A steel strip entrance/exit seal structure for an atmosphere heating furnace is provided with a triangular prism-shaped block having both side surfaces that are on the same plane as both outer surfaces and further extend from the tip of an inclined plate to form a top side. Regarding.

The case where the atmosphere heating furnace entrance/exit seal structure of the present invention is applied to a horizontal bright annealing furnace will be described below as an example.

FIG. 1 is a partially removed perspective explanatory view showing an embodiment of the present invention, and FIG. 2 is a view taken along the line AA in FIG. 1.

In the steel strip entrance/exit seal structure of the present invention, the furnace box end has an inclined plate 10 facing both sides of the steel strip and inclined and reduced in the direction of the entrance/exit to form an opening for steel strip entrance/exit, and the inclined plate 10 Sealing materials 11a and 11b made of felt or the like are provided so as to sandwich both sides of the steel strip 5 that enters and exits the outer surface and the opening, and sealing materials 11a and 11b are placed in contact with both back surfaces of the sealing materials 11a and 11b. Holding plates 12a, 12b and holding plates 12a, 12b that hold 11a, 11b
It is the same as the conventional seal structure in that there are holding force adjustment bolts (not shown) and side plates 14a and 14b on the left and right sides. However, in the conventional structure, triangular prism blocks 15 are further installed between both sides of the steel strip inlet/outlet openings formed at both end faces of both inclined plates 10 and the furnace box side plates 14a, 14b. different from. Both sides 1 of triangular prism block 15
5a and 15b are on the same plane as both outer surfaces of the inclined plate 10, and a part thereof extends from the tip of the inclined plate and intersects to form a top side. A seal plate 11 that simultaneously covers both outer surfaces of the inclined plate 10, both side surfaces 15a and 15b of the triangular prism block, and both sides of the steel strip 5.
a, 11b, and seal plates 11a, 11
Pressing plates 12a and 12b are provided to press b from both sides.

In the above seal structure, both outer surfaces of the inclined plate 10 and both side surfaces 15a, 15 of the triangular prism block are
b and both sides of the steel strip 5 are provided with seal plates 11a, 1.
1b and is pressed down with the presser plates 12a and 12b, the atmospheric gas 16 inside the furnace is prevented from leaking into the outside air.

In the conventional seal structure, the line contact between the side plates 14a, 14b and the ends of the sealing materials 11a, 11b acts as a seal, and since the sealing in this area is incomplete, the atmospheric gas 16 inside the furnace leaks to the outside air 17. However, in the seal structure of the present invention, both outer surfaces of the inclined plate 10, both sides of the triangular prism block, and both sides of the steel strip are pressed with a holding plate without any gaps through the sealing material, and the wire seal is Since it is a face seal rather than a seal, it is possible to maintain the airtightness inside the furnace extremely efficiently.

In addition, both sides 15a and 15b of the triangular prism block
may be on the same plane as the outer surface of the opening inclined plate 10, and there is no particular limitation on its shape, but for example, as shown in FIG. Curved surface, holding plates 12a, 12
If b is also pressed with the same curved surface, the sealing materials 11a, 11b and the pressing plates 12a, 12b will come into contact smoothly and uniformly, and a sealing action can be exerted, thereby providing a more favorable effect.

Although the above description has been made regarding a bright annealing furnace for steel plates, and only a horizontal annealing furnace is shown in the figure, the same sealing structure can also be employed in a vertical annealing furnace. Furthermore, it can be applied not only to atmospheric gas furnaces such as carburizing furnaces and carbonitriding furnaces other than bright annealing furnaces, but also to seal structures of heat treatment furnaces for general steel materials, non-ferrous metal materials, etc.

Next, examples of the present invention will be described.

(Example) In a bright annealing furnace with a processing capacity of 1 t/hr and an effective furnace length of 8 m, stainless steel with a width of 550 mm and a thickness of 0.5 mm was treated at an annealing temperature of 1150° C. for a heating time of 80 seconds. The atmospheric gas is 75% hydrogen and 25% nitrogen. If the seal at the furnace entrance and exit is of the conventional type, the atmospheric gas pressure will be 3 to 4 water columns.
mm, gas consumption was 40 to 50 Nm ³ /hr, and dew point was -50°C.

When the seal at the entrance and exit of the annealing furnace was modified to the seal structure of the present invention and the furnace was operated, the atmospheric gas pressure was improved to 12 to 16 mm of water column, the gas consumption to 20 to 25 Nm ³ /hr, and the dew point to -55°C. In other words, the amount of gas leakage is proportional to the square root of the gas pressure difference, so if the pressure before modification is kept the same as the pressure after modification, the flow rate will be double, so there is a sealing effect that reduces the amount of leakage to 1/4. It turns out.

(Effects of the Invention) As explained above, between both sides of the steel strip inlet/outlet opening formed by each end face of the inclined plate forming the steel strip inlet/outlet opening of the atmosphere heating furnace and the furnace box side plate. By installing a triangular prism-shaped block in the furnace and completely sealing the entrance and exit of the steel strip, we were able to significantly reduce the consumption of atmospheric gas in the furnace and lower the dew point. Therefore, manufacturing costs are reduced,
Moreover, products of excellent quality and great commercial value can be obtained, so the effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view with a part of the entrance/exit seal structure of the atmosphere heating furnace of the present invention removed, and FIG.
3 is an explanatory diagram of a conventional horizontal bright annealing furnace, FIG. 4 is an explanatory diagram of a conventional vertical bright annealing furnace, and FIG. 5 is a vertical cross-sectional diagram of a conventional entrance/exit seal structure. FIG. 6 is a longitudinal cross-sectional view of the steel plate in the traveling direction. DESCRIPTION OF SYMBOLS 1... Inlet part, 2... Outlet part, 3... Furnace box, 4... Heat source, 5... Steel strip, 6... Cooler, 7... Conveyance roller,
8... Atmospheric gas inlet, 9... Atmospheric gas outlet, 10
...furnace body opening, 11a, b...sealing material, 12a,
b... Holding plate, 13a, b... Adjustment bolt, 14a,
b... Side plate, 15... Block, 15a, b... Block side, 16... Atmosphere gas, 17... Outside air.

Claims (1)

[Scope of Claims] 1. A steel strip entrance/exit seal structure for an atmospheric furnace in which steel strips are continuously heat-treated, wherein both sides of the steel strip at the end of the furnace box are inclined and reduced in the direction of the entrance/exit. an inclined plate forming an opening for the strip to be taken in and out; a sealing material provided to sandwich both sides of the steel strip passing in and out of the opening; a sealing material being in contact with both back surfaces of the sealing material to sandwich the sealing material. In a steel strip inlet/outlet seal structure for an atmospheric furnace having a holding plate;
are on the same plane as both outer surfaces of the inclined plate,
A steel strip entrance/exit seal structure for an atmosphere heating furnace, further comprising a triangular prism-shaped block having both side surfaces that partially extend from the tip of the inclined plate and intersect to form a top side.