JPH05295452A - Vertical type heat treatment furnace with muffle - Google Patents

Abstract

PURPOSE:To restrain the heat deformation caused by radiation heat from the muffle side in an expansion joint part by forming the expansion joint part in a muffle with an expandable cylindrical body and a bellows and interposing a heat insulating material between the cylindrical body and the bellows. CONSTITUTION:In a vertical type heat treatment furnace, a heating zone part, the expansion joint part 9, a slow cooling zone part 7 and cooling zone part are arranged from the lower part to the upper part in order. The muffle 11 has a muffle body 15 and a baffle 16, and in the baffle 16, an opening hole for passing a strip is formed. The expansion joint part 9 at the lower end of the slow cooling zone part 7 is formed as a telescopic shape and has cylindrical bodies 22 expandable in the vertical direction at the upper and lower parts and the bellows 31 an outer side from the cylindrical body, and the heat insulating material is packed into a gap between the cylindrical body 22 and the bellows 31. The surface of the cylindrical body 22 at the metallic strip side is arranged so as to shift in the thickness direction of the metallic strip from the opening hole for passing the strip formed in the baffle 16 at the upper part of the muffle 11. Thus, the radiation heat in the muffle 11 to the cylindrical body 22 is restrained and the contact of the cylindrical body 22 with the metallic strip can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical heat treatment furnace equipped with a muffle.

[0002]

2. Description of the Related Art A vertical heat treatment furnace equipped with such a muffle is used, for example, for bright annealing a stainless steel strip. Such a vertical heat treatment furnace is configured, for example, by arranging a heating zone part, an expansion joint part, an annealing zone part, and a cooling zone part in order from bottom to top along a metal strip running path in the vertical direction. In the tropical zone, a muffle is suspended through the furnace shell, and the burner provided in the furnace shell heats the muffle, thereby heat-treating the stainless steel strip threaded through the muffle. In such a bright annealing furnace for a stainless steel strip, the inside of the muffle, the annealing zone and the cooling zone are all filled with a mixed gas of hydrogen and nitrogen, which are atmospheric gases, and the oxidation of the heated stainless steel strip occurs. The atmospheric gas pressure is a positive pressure to prevent outside air from entering the furnace.

The expansion joint is provided in a gap between a tubular body which can be vertically expanded and contracted like a telescope and a bellows provided outside thereof.
A heat insulating material is interposed so as to allow thermal expansion and contraction. The tubular body is divided in the circumferential direction, whereby thermal deformation can be permitted and dealt with. In the prior art, the tubular body is provided so as to project at the same position as the inner peripheral surface of the through hole in the heating muffle upper part of the muffle or near the metal band.

[0004]

In such a prior art, the tubular body is heated to a high temperature mainly by the radiant heat from the inside of the muffle, and the lower part of the telescopic tubular body is deformed by the thermal deformation to approach the metal strip. Or, there is a risk of contact. In addition, when such a tubular body is bent and deformed so as to be close to the metal strip, a gap is created in the heat insulating material, which causes a so-called heat spot of high temperature in a part of the bellows, which also damages the bellows. To do. When the bellows is damaged, the atmosphere gas leaks to the outside, and a flame of hydrogen gas contained in the atmosphere gas is generated.
In this way, the atmospheric gas leaks to the outside, making operation impossible. And continuous operation for a long time is impossible. Moreover, it is further desired to stably obtain a stainless steel strip of excellent quality in the heat treatment such as bright annealing.

An object of the present invention is to suppress thermal deformation due to radiant heat from the muffle side of the expansion joint portion, improve durability, prolong life, and stably perform excellent heat treatment. The present invention is to provide a vertical heat treatment furnace including the muffle.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a heating band part for heating while passing a metal band in a muffle along a vertical metal band running path, an expansion joint part, and an annealing band part. In the vertical heat treatment furnace including a muffle in which the cooling zone and the cooling zone are sequentially arranged from the bottom to the top, the expansion joint part includes a tubular body that can be vertically telescopically expanded and contracted, and an outer side of the tubular body, A bellows that is expandable and contractible, and a heat insulating material that is interposed between the cylinder and the bellows. Placed,
This is a vertical heat treatment furnace equipped with a muffle characterized in that radiant heat from the inside of the muffle to the cylindrical body is suppressed.

[0007]

According to the present invention, the telescopic cylinder forming the expansion joint portion interposed between the heating zone portion and the slow cooling zone portion is a through hole formed in the baffle above the muffle. It is arranged on the outer side in the thickness direction of the metal strip, so that it becomes possible to suppress the radiant heat from the inside of the muffle to the tubular body. Therefore, it becomes possible to suppress the thermal deformation of the tubular body, so that the tubular body does not come into contact with the metal strip and the metal strip is not damaged or broken, and the thermal deformation of the tubular body is as described above. The suppression suppresses a gap in the heat insulating material, and the heat insulating material suppresses the bellows from reaching a high temperature. Thus, the durability of the expansion joint portion is improved, the life of the expansion joint portion is extended, and continuous operation for a long period of time becomes possible. Therefore, it is possible to stably produce a stainless steel strip of excellent quality.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged cross-sectional explanatory view of a part of the present invention, and FIG. 2 is a simplified side view of the entire vertical heat treatment furnace. The stainless steel strip 1 to be bright annealed rises vertically from the entrance-side deflector roll 2 along the metal strip travel path, passes through the pair of deflector rolls 3 and 4, and is guided by the deflector roll 5 on the exit side. It A heating zone 6 for heating the stainless steel strip 1 between the deflector rolls 2 and 3, an expansion joint 9 capable of expanding and contracting vertically, a slow cooling zone 7 for gradually cooling the stainless steel strip 1, and a stainless steel strip. The cooling zone 8 for cooling 1 is sequentially arranged from bottom to top.

The heating zone 6 includes a furnace shell 10 and the furnace shell 10.
Muffle 11 penetrating the inside and furnace shell 10
Attached to the combustion chamber 1 between the furnace shell 10 and the muffle 11
2 and a burner 13 such as a gas burner provided so as to face 2. Muffle 11, expansion joint section 9, slow cooling zone section 7, cooling zone section 8 and chute 14 between deflector rolls 4 and 5.
Atmospheric gas is supplied inside, and this atmospheric gas is a mixed gas containing hydrogen and nitrogen, and is maintained at a positive pressure to prevent air from entering from the outside.

As shown in FIG. 1, the muffle 11 includes a muffle body 15 and a baffle 16 fixed to the upper portion of the muffle body 15. The baffle 16 has a through hole 18 through which the stainless steel strip 1 passes. It A flange 19 is fixed to the upper end surfaces of the muffle body 15 and the baffle 16. A flange 20 is fixed to the lower end surface of the slow cooling zone 7. The expansion joint part 9 is interposed between the flanges 19 and 20. The upper part of the muffle 11 is suspended.

FIG. 3 is a plan view of the muffle 11, and FIG.
FIG. 3 is an enlarged plan view of a part of the expansion joint part 9. The opening 18 through which the stainless steel strip 1 passes has a rectangular horizontal cross section, and the upper portion of the baffle 16 has the opening 18
To the thickness direction of the stainless steel strip 1 (horizontal direction in FIG. 1, vertical direction in FIGS. 3 and 4), the inclined surface 46 becomes wider as it goes upward.

FIG. 5 is a sectional view of the expansion joint portion 9, and FIG.
FIG. 3 is an exploded perspective view of a part of the expansion joint part 9. The lower and upper flanges 47, 48 of the expansion joint 9 are hermetically welded and connected as indicated by reference numerals 49, 50. The expansion joint part 9 has a telescopic-like tubular body 22 which is vertically expandable and contractible. This cylindrical body 22 is the first inner cylinder 2
3, the second inner cylinder 24 arranged outside thereof, and the mounting piece 2
It consists of 6,35. Each of the inner cylinders 23, 24 has a flange 4
It is fixed to 7, 48 via mounting pieces 26, 35, respectively. As shown in FIGS. 5 and 6, the inner cylinder 23 is divided with a gap 25 along the circumferential direction of the opening 51 through which the stainless steel strip 1 is passed, whereby thermal deformation is allowed. A mounting piece 26 is fixed to the lower portion of the inner cylinder 23,
It is fixed to the flange 47 together with the rib 27. A mounting piece 28a which is a part of the frame body 28 is erected on the flange 47, and the mounting piece 28a is reinforced by the rib 29 to cope with thermal deformation. A gap 30 is also formed in the mounting piece 28a along the circumferential direction of the opening 51 to allow thermal deformation. A lower portion 32 of a metal bellows 31 that is vertically expandable and contractable is fixed to a mounting piece 28b of the frame body 28. The configuration related to the other inner cylinder 24 is also similar, and the upper end portion 33 of the bellows 31 is fixed to a mounting piece 34b which is a part of the frame body 34 fixed to the flange 48. A mounting piece 35 is fixed to the inner cylinder 24, is reinforced by ribs 36, and is a part of the frame 34.
It is fixed to the flange 4 as well as to 4a. The ribs 27 are inserted into the inner cylinder 24 so that the inner cylinders 23, 24
Is formed with a notch 37 for allowing vertical displacement.

A heat insulating material 38 is filled and interposed in the gap between the cylindrical body 22 and the bellows 31. This heat insulating material 38 is
For example, it is made of glass fiber or the like and is expandable and contractible.

On the outside of the bellows 31, there is a cylinder consisting of a first outer cylinder 39 fixed to the flange 47 and a second outer cylinder 40 fixed to the flange 48 outside the first outer cylinder 39. The body 41 is provided to protect the bellows 31 and prevent heat from being dissipated by the outside air.

The surface 52 of the inner cylinder 23 of the cylindrical body 22 on the stainless steel strip 1 side is located in the thickness direction of the stainless steel strip 1 (right side in FIG. 5) rather than the through hole 18 formed in the baffle 16 above the muffle 11. On the one hand) is displaced by a distance L1. This makes it possible to suppress radiant heat from the inside of the muffle 11 to the cylindrical body 22. Thus, during the bright annealing of the stainless steel strip 1, when the temperature inside the upper portion of the muffle 11 is, for example, 800 to 900 ° C., the temperature rise of the cylindrical body 22, particularly the inner cylinder 23 and the mounting piece 26 is suppressed. .. Therefore, the inner cylinder 23 and the mounting piece 26 are not thermally deformed to hang down below the mounting piece 26 and the cylindrical body 23 is not displaced downward, which prevents the inner cylinder 23 from contacting the stainless steel strip 1. .. Also, this inner cylinder 23
And by suppressing the thermal deformation of the mounting piece 26,
No gap is formed in the heat insulating material 38, so that the bellows 31 is not heated to a high temperature, and a so-called heat spot of a high temperature is not locally generated on the bellows 31. In this way, the expansion joint 9
The durability can be improved and its life can be extended.

The present invention can be widely applied not only for the bright annealing of the stainless steel strip 1 but also for the heat treatment of other metal strips.

[0017]

As described above, according to the present invention, the telescopic cylindrical body of the expansion joint portion interposed between the heating zone portion and the slow cooling zone portion is formed in the baffle above the muffle. It is arranged outside the plate opening 18 in the thickness direction of the metal strip,
This makes it possible to suppress the radiant heat from inside the muffle to the cylindrical body, which suppresses thermal deformation of the cylindrical body, which prevents the cylindrical body from contacting the metal strip and also prevents the thermal insulation It is possible to prevent the formation of gaps and maintain the heat insulating effect on the bellows. Thus, the durability of the expansion joint portion is increased, its life is extended, and continuous operation for a long period of time becomes possible. Therefore, since excellent heat treatment can be stably performed, it is possible to stably produce, for example, a stainless steel strip of excellent quality.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional explanatory view showing a structure in the vicinity of a part of an expansion joint part 9 of an embodiment of the present invention.

FIG. 2 is a simplified sectional view of an entire vertical heat treatment furnace including a muffle according to an embodiment of the present invention.

FIG. 3 is a plan view of the muffle 11.

FIG. 4 is a simplified plan view near an opening 51 of the expansion joint part 9.

FIG. 5 is an enlarged cross-sectional view of an expansion joint section 9.

FIG. 6 is an exploded perspective view of a part of the expansion joint section 9.

[Explanation of symbols]

 1 Stainless Steel Strip 6 Heating Zone 7 Cooling Zone 8 Cooling Zone 9 Expansion Joint 10 Furnace Shell 11 Muffle 15 Muffle Main Body 16 Baffle 18 Through Plate Opening 22, 41 Cylindrical Body 31 Bellows 38 Insulation Material

Claims (1)

[Claims] 1. A heating band part for heating while passing a metal band through a muffle along a vertical metal band running path, an expansion joint part, an annealing band part, and a cooling band part. In a vertical heat treatment furnace equipped with a muffle that is sequentially arranged from the top to the top, the expansion joint part is a telescope-like vertically expandable tube, and a bellows that is expandable up and down outside the tube body. With the heat insulating material interposed between the body and the bellows, the tubular body is arranged outside the through-hole formed in the baffle above the muffle in the thickness direction of the metal strip. A vertical heat treatment furnace equipped with a muffle that suppresses radiant heat to a cylindrical body.