JPH09249921A - Support roll device for bright annealing furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the white powder seizure, staining and flawing of a steel strip by contact with support rolls in a vertical type bright annealing furnace. SOLUTION: This support roll device 300 for the bright annealing furnace is arranged on both sides of a steel strip pass line. The device consists of the support rolls 100 and cooling jackets 200 for stowing the support rolls. The roll body part 10 of each support roll is made of an air permeable perforated material. Double pipes 11 consisting of an outside pipe 12 allowing the passage of an atmosphere gas 15 and an inside pipe 13 allowing the passage of cooling water 16 are passed in the axial central part of the material. The outside pipe within the roll body section is provided with many pores 12A. The cooling jacket is opened to face the steel strip S and the cooling water is passed therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support roll device for a bright annealing furnace, and more particularly to a support roll device for a bright annealing furnace suitable for use in a vertical cold annealing furnace for stainless cold-rolled steel strip.

[0002]

2. Description of the Related Art In the process of manufacturing a stainless steel strip, so-called bright annealing in which a product is given a metallic luster peculiar to the stainless steel strip is generally performed in a reducing gas atmosphere. FIG. 2 shows an overall cross-sectional view of a general vertical type bright annealing furnace which is a kind of furnace for bright annealing.

The furnace has a vertical structure with a height of 30 to 40 m, 1 is a strip shooter, 2 is a top roll, 3 is a heating zone, 4
Is a slow cooling zone, 5 is a canoeing prevention device, 6 is a cooling zone, 7
Is a felt seal, 8 is a bridle roll, 9 is a dancer roll, 30 is a support roll, 60 is a plenum chamber, and S is a steel strip (stainless steel strip). The steel strip S is sent into the furnace sealed by the felt seal 7 by the bridle roll 8, passes through the strip shooter 1, is turned by the top roll 2, and is guided to the heating zone 3. The steel strip S that has entered the heating zone 3 is heated by, for example, a heating wire on both sides and annealed. To increase the heat efficiency, the heating wire is steel strip S
In general, it is preferable to bring the steel strip as close as possible to the steel sheet. However, if the steel strip is brought too close to the steel sheet, the steel strip comes into contact with the heating wire, which may cause a short circuit accident or a scratch on the steel strip.

In order to prevent this, support rolls 30 are provided at the inlet and outlet of the heating zone, for example, to prevent the above-mentioned short circuit accident and the occurrence of scratches. Further, since stainless steel is deteriorated in corrosion resistance and mechanical properties unless it is rapidly cooled after being annealed, the steel strip S is sent out from the heating zone 3 and then sequentially sent to the slow cooling zone 4 and the cooling zone 6, It is discharged to the outside of the furnace through the felt seal 7. The dancer roll 9 applies tension to the steel strip S in the furnace.

However, in the rapidly cooled steel strip S, a cooling rate difference inevitably occurs in the strip width direction, so that a non-uniform shape of the thermal strain caused thereby causes a defective shape, and the slow cooling zone 4 and the cooling zone 6 are affected. The steel strip S comes into contact with the cooling chamber such as the plenum chamber 60, and scratches are generated. In order to prevent the steel strip S from coming into contact with the cooling chamber due to the defective shape, a canoeing prevention device 5 is provided on the inlet side of the cooling strip 6, and a support roll is also used here.

Regarding the bright annealing furnace (abbreviated as BA furnace as appropriate), for example, Handbook of Stainless Steel (No. 3)
Edition, Stainless Steel Association, edited by Nikkan Kogyo Shimbun, P.842, Steel Handbook III (1) Rolling foundation / steel sheet (Japan Iron and Steel Institute, Maruzen)
See page 705 for explanation. The support roll 30 is made of carbon, ceramics or the like as a material so as not to scratch the surface of the steel strip S, and is exposed to a high temperature of 1200 to 900 ° C., so that water is constantly passed inside to be cooled. . And, in order to maintain the roundness of the roll, it is constantly driven to rotate.

On the other hand, in the BA furnace, AX gas (H ₂ = 75%, N ₂ = 25%) is usually used as the atmospheric gas, and bricks, mortar, etc. are used as the refractory material in the furnace. A large amount of peculiar white powder is generated and floats inside. This white powder contains a stainless steel component, a BA brick component, a catalyst component for an ammonia decomposer for AX gas generation, etc., and is a compound having a relatively low crystallinity mainly composed of B, Mn, S, and O, and a small amount of Fe. , Cl, Cr, K, Na, Mg, Si, A
It is a powder containing l, Zr, La, etc. and having an average particle size of about 6 to 10 μm.

Despite regular cleaning of the furnace, this white powder adheres to the support rolls and also sticks to the high temperature steel strip that contacts the support rolls, causing seizure and stain marks (white powder) on the steel strips. There is a problem of causing seizure stain marks).

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention provides a support roll for a bright annealing furnace which can support a steel strip in a non-contact manner in order to prevent white powder seizure and stain marks from entering the steel strip due to contact with the support roll. The challenge is to provide.

[0010]

SUMMARY OF THE INVENTION The present invention is a support roll apparatus for a bright annealing furnace arranged on both sides of a steel strip pass line in a vertical bright annealing furnace, the support roll containing the support roll and the support roll. The support roll consists of a cooling jacket.The support roll is made of a porous material that allows the body of the roll to be aerated, and its axis has a double pipe consisting of an outer pipe through which atmospheric gas flows and an inner pipe through which cooling water flows. A large number of pores are provided in the outer tube in the section of the roll body, the cooling jacket is opened facing the steel strip, and cooling water is passed inside. A support roll device for an annealing furnace.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Since the present invention has the above configuration,
By sending the atmospheric gas under pressure to the outer tube of the double tube, the atmospheric gas is pressed into the porous material through the pores of the outer tube, reaches the surface of the roll body, and is jetted into the furnace. Since the support roll is housed in the cooling jacket that opens facing the steel strip, almost all of the spouted atmospheric gas is blown toward the steel strip. As a result, static pressure is generated between the steel strip and the support roll devices on both sides, and the steel strip is stably supported in a non-contact state. Therefore, the white powder adhering to the surface of the support roll does not adhere to the surface of the steel strip. Further, it also plays an essential role as a support roll, and can prevent the steel strip from coming into contact with the furnace wall and the heating wire of the heating zone, and / or the slow cooling zone and the cooling chamber of the cooling zone.

Even if the steel strip and the support roll come into contact with each other due to an accident, the surface of the support roll is in a state in which white powder is unlikely to adhere due to the self-injection of the atmospheric gas.
The probability of white powder seizure and flaws on steel strips is greatly reduced. Therefore, according to the present invention, while fulfilling the original mission of the support roll to prevent the occurrence of scratches on the steel strip due to contact with the furnace wall or the side wall, it is possible to simultaneously prevent the occurrence of stains due to white powder burning.

In order to prevent heat damage to the support roll and the cooling jacket, cooling water is made to flow through the inner pipe of the double pipe and the inside of the cooling jacket. Also, since the support roll is stored in a cooling jacket that opens facing the steel strip, the pressure of the atmospheric gas that is press-fitted into the support roll can be adjusted appropriately according to the plate width and plate thickness, for example, to save energy. Is also possible.

[0014]

EXAMPLES Next, the structure of the support roll device will be described with reference to examples. FIG. 1 is a cross-sectional view showing an embodiment of the present invention, (a) is a vertical cross-sectional view showing the structure of a support roll, and (b) is a horizontal cross-sectional view showing a state in which a support roll device is installed in a furnace. In FIG. 1, 10 is a roll body made of a porous material, 11 is a roll shaft made of a double pipe, 11A is an external connection pipe, 12 is an outer pipe, 12A is a pore, 13 is an inner pipe, 14 is a rotary joint, 15 is atmosphere gas, 16 is cooling water, 17
Is an iron skin, 18 is a heat insulating material, 19 is a brick, 20 is a heating wire made of, for example, pure molybdenum, 100 is a support roll, 200 is a cooling jacket, 201 is a cooling water pipe, 300 is a support roll device, and C is the furnace center. is there. The same members as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 1A, the support roll
The roll body 10 of 100 is made of a porous material that is made of carbon or ceramic or the like as a raw material and is fired into a porous structure so as to have air permeability. In this embodiment, the roll diameter is 130 mmφ, the roll body length is 1400 mm, and the pore diameter is 0.05 to
It has a rough porous shape of 1.0 mmφ. The roll shaft 11 has a double pipe structure, and cooling water 16 is supplied to the inner pipe 13 from one end of the roll shaft 11 so as to cool the roll body 10 and escape to the other end.

The outer tube 12 has an atmosphere gas (AX gas, H ₂
= 75%, N ₂ = 25%) 15 is pumped from one end. Since the other end of the outer tube 12 is sealed and a large number of pores 12A of about 5 mmφ are opened in the outer tube 12 in the roll body 10 section,
The pressure-fed atmospheric gas 15 is press-fitted into the porous material forming the roll body 10 through the pores 12A, and is ejected from the roll surface through a large number of pores in the porous material. The pressure for pumping is 0.1 to ² kgf / cm ² . Also, roll axis
One end of 11 is connected to an external connection pipe 11A coaxial with this by a rotary joint 14, and can freely rotate with respect to the outside.

As shown in FIG. 1 (b), this support roll 100 is, for example, a box-shaped cooling jacket 200 in which one surface having the long side in the roll axis direction is opened, and the roll axis is parallel to the long side. Then, the support roll device 300 is rotatably stored and configured. The cooling jacket 200 is made of, for example, stainless steel, and its own wall has a hollow structure so that cooling water can flow.

The cooling jacket 200 is attached to the brick 19 at the position where the back surface of the opening surface does not interfere with the heating wire 20 in the heating zone 3 of the BA furnace, for example.
Cooling water 16 is supplied to the inside through a cooling water pipe 201 made of stainless steel, which penetrates the heat insulating material 18 and the brick 19 and is connected to the back surface. Support roll 100 has cooling jacket 200
In the state where the exposed portion coming to the opening surface of is facing the steel strip S, it is constantly driven to rotate by a drive device (not shown).

The atmospheric gas 15 ejected from the surface of the support roll 100 is directly from the opening surface, and from the other surfaces, the storage space of the cooling jacket 200 is made to have a high pressure, and then the atmosphere gas 15 flows to the opening surface. It is blown onto the steel strip S, which creates a static pressure between the support roll device 300 and the steel strip S. Therefore, even if the steel strip S becomes unstable and is likely to come into contact with the support roll device 300, the static pressure exerts a repulsive force, so that they do not come into contact with each other.

Thus, the support roll device of the present invention
In the case of 300, since the support roll 100 is stored in the cooling jacket 200 that faces the steel strip S and opens, the atmospheric gas ejected from the entire circumference of the support roll 100.
Almost all of 15 can be used as a static pressure generation source between the steel strip S, and this static pressure can stably support the steel strip S in the vicinity of the furnace center C in a non-contact state. The belt S is the brick of the support roll device 300 itself and the furnace wall.
It is possible to effectively prevent contact with the heating wire 20 and the like.

Although only the right side of the furnace center C is shown in FIG. 2, the left side has the same structure. Further, the distance from the front surface of the support roll device 300 to the furnace center C in this embodiment is 50 mm. In this embodiment, an example in which the support roll device is attached to the heating zone is shown.
It goes without saying that the present invention is not limited to this, and can be appropriately arranged in the slow cooling zone, the cooling zone, and the canoeing prevention device.

[0022]

According to the present invention, since the stainless steel strip in the bright annealing furnace can be supported in a non-contact manner, it can be brought into contact with the furnace wall or the heating wire in the heating zone, or in the slow cooling zone, the cooling zone or the like. Not only does it prevent the occurrence of scratches and operating troubles on the stainless steel strip due to the contact with the side wall of the cooling chamber, but it also has the remarkable effect of simultaneously preventing the stain defect due to white powder seizure due to the contact with the support roll, which was a conventional problem. Play.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an overall sectional view of a general vertical bright annealing furnace.

[Explanation of symbols]

 1 Strip shooter 2 Top roll 3 Heating zone 4 Slow cooling zone 5 Canoeing prevention device 6 Cooling zone 7 Felt seal 8 Bridle roll 9 Dancer roll 10 Roll body (porous material) 11 Roll shaft (double pipe) 11A External connection Piping 12 Outer tube 12A Pore 13 Inner tube 14 Rotary joint 15 Atmosphere gas 16 Cooling water 17 Steel skin 18 Insulation material 19 Bricks 20 Heating wire 30,100 Support roll 60 Plenum chamber 200 Cooling jacket 201 Cooling water pipe 300 Support roll device C furnace Center S steel strip (stainless steel strip)

Claims (1)

[Claims] 1. A support roll device for a bright annealing furnace arranged on both sides of a steel strip pass line in a vertical bright annealing furnace, comprising a support roll and a cooling jacket for storing the support roll. Is made of a porous material that allows the roll body to be permeable, and a double pipe consisting of an outer pipe for flowing atmospheric gas and an inner pipe for flowing cooling water penetrates through the axial center of the roll body portion, A support roll device for a bright annealing furnace, characterized in that the outer tube is provided with a large number of pores, the cooling jacket is opened facing the steel strip, and cooling water is passed inside.