WO2019069510A1 - Vertical heat-treating muffle furnace - Google Patents

Abstract

In the present invention, when a metal strip is being conveyed through the interior of a muffle, there are provided: a heating zone for heating the metal strip that is moving into the muffle from the outside of the muffle, the heating zone being provided upstream from the metal strip in the movement direction thereof; and a slow-cooling zone for slow-cooling the metal strip that is moving through the interior of the muffle, the slow-cooling zone being provided downstream from the metal strip in the movement direction thereof. When the metal strip that has been slow-cooled in the slow-cooling zone is being cooled in a cooling zone, cooling air is introduced into a slow-cooling space between the slow-cooling zone and the muffle via an introduction port, the amount of the cooling air heated in the slow-cooling space that is blown out via an exhaust port is adjusted by a flow-rate-controlling valve, and the slow-cooling temperature of the metal strip is controlled.

Description

Vertical muffle type heat treatment furnace

The present invention relates to a vertical muffle type heat treatment furnace. In particular, the metal strip is transported inside the muffle, which is disposed vertically and accommodates the processing atmosphere gas, and moves inside the muffle from the outside of the muffle upstream in the moving direction of the metal strip in the muffle. A heating zone for heating the metal strip, a slow cooling zone for slow cooling the heated metal strip moving inside the muffle at a position downstream of the heating zone in the moving direction of the metal strip, and the slow cooling zone In the vertical muffle type heat treatment furnace provided with a cooling zone for cooling the gradually cooled metal strip on the downstream side of the moving direction of the metal strip rather than the cold zone, the metal strip heated through the inside of the muffle in the heating zone The metal strip heated in the heating zone is subjected to annealing in the above-mentioned annealing zone to lead it to the cooling zone. And it has a characteristic feature that makes it easy to gradually cooled to an appropriate temperature in the slow cooling zone.

In the heat treatment of metal strips such as steel strips, a vertical muffle type heat treatment furnace is conventionally used.

Then, as such a vertical muffle type heat treatment furnace, conventionally, as shown in Patent Document 1, the metal strip is disposed inside the muffle which is vertically disposed and the processing atmosphere gas is accommodated therein. A heating zone for heating the metal strip moving from inside the muffle from the outside of the muffle is provided on the upstream side in the moving direction of the metal strip for conveying and heat treating from the bottom to the top, and thus the metal strip heated in the heating zone Is used in the cooling zone provided downstream of the moving direction of the metal strip.

However, if the metal strip heated inside the muffle in the heating zone as described above is immediately led to the cooling zone and cooled, the temperature of the metal strip drops rapidly, causing the metal strip to deform. There was a problem.

And, in order to prevent the metal strip heated in the heating zone from being rapidly cooled and deformed in the cooling zone, as described in Patent Documents 2 and 3, etc. Between the cooling zone and the cooling zone, a cooling zone is provided, and it is intended to use one in which the metal strip heated in the heating zone is gradually cooled in the cooling zone before being introduced into the cooling zone.

Here, in the thing shown by patent document 2, the said slow cooling zone is provided so that the said heating zone may be continued, and in the thing shown by patent document 3, the said slow cooling zone is mentioned. It is provided so as to be continuous with the heating zone and a cylindrical body which can be expanded and contracted in the vertical direction.

For this reason, in what is shown by patent documents 2 and 3, the heat from the heating zone is led as it is to the slow cooling zone on the downstream side, and the metal strip heated in the heating zone is appropriately cooled in this slow cooling zone. In order to cool the heated metal strip sufficiently in the annealing zone, it is necessary to increase the length of the annealing zone, which increases the manufacturing cost. There was a problem such as an increase in size of the device.

Japanese Utility Model Publication No. 3-32517 JP-A-5-295449 Unexamined-Japanese-Patent No. 5-295452

According to the present invention, the metal strip is transported in the muffle, which is vertically disposed and the processing atmosphere gas is contained therein, and a heating zone is provided on the upstream side of the movement direction of the metal strip in the muffle, In the heating zone, a metal strip moving inside the muffle from the outside of the muffle is heated, and a slow cooling zone is provided at a position downstream of the heating zone in the moving direction of the metal strip to move the inside of the muffle. A vertical muffle type heat treatment provided with a cooling zone for gradually cooling the heated metal strip and further cooling the gradually cooled metal strip at a position downstream of the slow cooling zone in the moving direction of the metal strip It is an object of the present invention to solve the above-mentioned problems in a furnace.

That is, according to the present invention, in the vertical muffle type heat treatment furnace as described above, the metal strip heated passing through the inside of the muffle in the heating zone is gradually cooled in the annealing zone to lead it to the cooling zone. It is an object of the present invention to make it easy to gradually cool the metal strip heated in the heating zone to an appropriate temperature in the annealing zone without lengthening the annealing zone. It is a thing.

In the present invention, in order to solve the problems as described above, the metal strip is conveyed inside the muffle which is disposed vertically and in which the processing atmosphere gas is accommodated, and the moving direction of the metal strip in the muffle A heating zone for heating the metal strip moving from the outside of the muffle to the upstream side from the outside of the muffle, and the above-mentioned heated metal moving inside the muffle to a position downstream of the heating zone in the moving direction of the metal strip In a vertical muffle type heat treatment furnace provided with a slow cooling zone for slow cooling of the strip and a cooling zone for cooling the slow cooling metal strip at a position downstream of the slow cooling zone in the moving direction of the metal strip An inlet for introducing a cooling gas into the space for slow cooling between the muffle and the slow cooling zone, and the space for slow cooling An exhaust port for exhausting the heated cooling gas and adjusting the amount of the heated cooling gas exhausted through the exhaust port to control the temperature of the metal strip to be gradually cooled in the annealing zone A temperature control unit was provided.

Then, as in the vertical muffle type heat treatment furnace in the present invention, heating is performed to move the inside of the muffle before introducing the metal strip to the cooling zone at a position downstream of the heating zone in the moving direction of the metal strip. In providing the annealing zone for annealing the metal strip, an inlet for introducing a cooling gas into the annealing space between the muffle and the annealing zone is provided, and heating is performed in the annealing space. An exhaust port for exhausting the cooling gas is provided, and the amount of the heated cooling gas exhausted through the exhaust port is adjusted by the temperature control unit to adjust the temperature of the metal strip to be gradually cooled in the annealing zone. The control makes it easy to slowly cool the metal strip heated in the heating zone to an appropriate temperature in the annealing zone before introducing it to the cooling zone.

Here, in the vertical muffle type heat treatment furnace in the present invention, a temperature detection device for detecting the temperature in the annealing space portion between the muffle and the annealing zone is provided, and the annealing is detected by this temperature detection device. It is preferable to adjust the above-mentioned temperature control part based on the temperature in the space part. In this way, it is easy to slowly cool the metal strip heated in the heating zone to a more appropriate temperature in the slow cooling zone based on the temperature in the slow cooling space portion detected by the temperature detection device. You will be able to do it.

In the vertical muffle type heat treatment furnace according to the present invention, the muffle is separated into a heating side muffle provided in the heating zone and an annealing side muffle provided in the annealing zone. It is preferable that the heating side muffle and the annealing side muffle are connected by a telescopic connection cylinder in a sealed state. In this way, the types of materials used for the heating side muffle heated to high temperature in the heating zone and the annealing side muffle annealing in the annealing zone are changed, and heating is performed as the annealing side muffle. It becomes possible to use an inexpensive one that is less heat resistant than the side muffle. Further, by connecting the heating side muffle and the annealing side muffle in a sealed state by the expandable connecting cylinder, it is possible to cope with the change in elongation due to heat in the heating side muffle and the annealing side muffle. .

In the vertical muffle type heat treatment furnace according to the present invention, it is preferable that the muffle be attached to the cooling zone in an expandable manner in a sealed state of the muffle. In this case, when the muffle is provided to the cooling zone, it is possible to cope with the change in the extension of the guide tube of the cooling zone due to heat.

In the vertical muffle type heat treatment furnace according to the present invention, the introduction port for introducing the cooling gas into the slow cooling space portion is provided at the lower side position of the slow cooling zone, while the slow cooling space portion is Preferably, the exhaust port for exhausting the heated cooling gas is provided at the upper side position of the slow cooling zone on the downstream side in the moving direction of the metal strip than the introduction port. In this way, the metal strip moving inside the muffle in the annealing zone can be cooled by the cooling gas introduced from the inlet at the lower side position of the annealing zone into the annealing space. Thus, the cooling gas whose temperature has been raised is guided to the upper side of the annealing zone in the annealing space, and is discharged from the annealing space through the exhaust port provided at the upper position of the annealing zone. Will be properly discharged.

In the vertical muffle type heat treatment furnace according to the present invention, as described above, the metal strip is moved inside the muffle before being led to the cooling zone at a position downstream of the heating zone in the moving direction of the metal strip. In order to provide the annealing zone for annealing the heated metal strip, an inlet for introducing a cooling gas into the annealing space between the muffle and the annealing zone is provided, and the annealing space is provided. An exhaust port for exhausting the heated cooling gas in the unit, and adjusting the amount of the heated cooling gas exhausted from the annealing space through the exhaust port by the temperature control unit; Since the temperature of the metal strip to be annealed in the annealing zone is controlled, the metal strip heated in the heating zone can be annealed without increasing the length of the annealing zone. Oite quickly be gradually cooled to a suitable temperature will allow a simple structure.

In the vertical muffle type heat treatment furnace according to one embodiment of the present invention, the metal strip is conveyed upward from the bottom of the muffle arranged in the vertical direction, and the outer side of the muffle in the heating zone upstream of the moving direction of the metal strip. The metal strip moving from the inside of the muffle is heated, and the heated metal strip moving inside the muffle is annealed in the annealing zone at a position downstream of the heating zone in the moving direction of the metal strip, the annealing zone It is a partial schematic cross-sectional explanatory drawing which showed the state which cools the metal strip annealed in the cooling zone in the moving direction downstream side of a metal strip rather than a metal strip. In the vertical muffle type heat treatment furnace which concerns on said embodiment, it is a partially schematic sectional explanatory drawing of the example of a change which changed the muffle used.

Hereinafter, a vertical muffle type heat treatment furnace according to an embodiment of the present invention will be specifically described based on the attached drawings. The vertical muffle type heat treatment furnace according to the present invention is not limited to the one shown in the following embodiment, and can be appropriately modified and implemented within the scope of the present invention.

In the vertical muffle type heat treatment furnace according to this embodiment, as shown in FIG. 1, a muffle which is disposed in the vertical direction and in which a reducing gas such as hydrogen gas and a processing atmosphere gas such as nitrogen gas are accommodated The metal strip S is conveyed from the bottom to the top through the inside of the ten.

Then, a heating zone 20 for heating the metal strip S moving inside the muffle 10 from the outside of the muffle 10 to the moving direction upstream side of the metal strip S in the muffle 10, and the metal strip S more than the heating zone 20 The slow cooling zone 30 for slow cooling the heated metal strip S moving inside the muffle 10 at a position downstream of the moving direction, and the slowing direction downstream of the metal strip S rather than the slow cooling zone 30 A cooling zone 40 for cooling the cooled metal strip S is provided.

Here, in this embodiment, as the muffle 10, the heating-side muffle 11 provided in the heating zone 20 for heating the metal strip S and the slow cooling zone 30 for slow cooling the heated metal strip S are provided. The heating side muffle 11 and the slow cooling side muffle 12 are sealed using the one separated from the cold side muffle 12 by means of the expandable connection cylinder 13 in a sealed state.

As described above, when the muffle 10 is separated into the heating side muffle 11 provided in the heating zone 20 and the annealing side muffle 12 provided in the annealing zone 30 for annealing the heated metal strip S, the temperature is obtained. There is no need to use the same heat-resistant material for the heating-side muffle 11 and the annealing-side muffle 12 that is gradually cooled to lower the temperature. The annealing side muffle 12 provided in the annealing zone 30 can be made of an inexpensive material having lower heat resistance than the heating side muffle 11, and the manufacturing cost and the like can be reduced.

Then, the upper flange 11a of the heating side muffle 11 is held on the heating side support member 21 provided on the upper surface of the heating zone 20, and the heating side muffle 11 is held to be able to expand and contract by heat. The upper flange 12a of the cold side muffle 12 is held on the slow cooling side support member 31 provided on the upper surface of the slow cooling zone 30, and the slow cooling side muffle 12 heats the stretchable connecting cylinder 13 by heat. It is held to be able to expand and contract through. When the heating side muffle 11 and the slow cooling side muffle 12 are connected by the connecting cylinder 13, the upper flange 11a of the heating side muffle 11 and the lower flange 13a of the connecting cylinder 13 are combined. While being connected by a connecting member (not shown) such as a bolt, the lower flange 12b of the slowly cooled muffle 12 and the upper flange 13b of the connecting cylinder 13 are connected by a bolt (not shown) or the like.

Further, when the metal strip S annealed in the annealing zone 30 is guided from the annealing side muffle 12 to the cooling zone 40, the guide pipe 41 is extended downward from the lower surface of the cooling zone 40, In the state in which the annealing side muffle 12 and the guide pipe 41 are sealed, they are connected by the expandable cooling side connecting cylinder 42.

Here, when connecting the annealing side muffle 12 and the guide pipe 41 extended downward from the cooling zone 40 by the cooling side connecting cylinder 42, the upper flange 12 a of the annealing side muffle 12 and the upper flange 12 a of the annealing side muffle 12. The lower side flange 42a of the cooling side connecting cylindrical body 42 is connected by a connecting member (not shown) such as a bolt, and the lower side flange 41a of the guide pipe 41 and the upper side flange 42b of the cooling side connecting cylindrical body 42 are bolts. It is connected by (not shown) etc.

Then, in the heating zone 20 for heating the metal strip S moving inside the muffle 10, the heating strip 20 provided on the outer peripheral side of the heating side muffle 11 in the muffle 10 is for heating between the heating side muffle 11 and the heating side muffle 11. A heating device 24 such as an electric heater is provided in the space portion 23, and the heating device 24 heats the metal strip S moving inside the heating side muffle 11.

Further, in the annealing zone 30 for annealing the metal strip S which is heated in the heating zone 20 and moves inside the muffle 10 as described above, a heat insulator is provided on the outer peripheral side of the annealing side muffle 12 in the muffle 10. A slow cooling band main body 32 is provided, and a slow cooling space 33 is formed between the heat insulator 32 and the slow cooling side muffle 12.

And while providing the inlet 34 which introduces the gas for cooling in the space part 33 for slow cooling in the lower part side of the said heat insulator 32, the cooling gas heated in the space part 33 for slow cooling is exhausted An exhaust port 35 is provided on the upper side of the heat insulator 32, and the cooling gas heated in the slow cooling space portion 33 is led to the exhaust path 36 through the exhaust port 35. Further, the discharge path 36 is provided with a flow control valve 37 as a temperature control unit for adjusting the temperature of the metal strip S to be gradually cooled in the annealing side muffle 12 in the annealing zone 30.

Further, the temperature of the space for slow cooling 33 is raised because the heat of the metal strip S heated in the heating zone 20 is thermally conducted to the slow cooling side muffle 12 so that the inlet 34 and the exhaust 35 are open. Then, an updraft is generated, and a cooling gas (here, air outside the furnace) naturally flows in from the lower inlet 34 and is naturally discharged from the upper exhaust 35.

The temperature detecting device 38 for detecting the temperature of the cooling gas heated in the space portion 33 for slow cooling in the slow cooling zone 30 is provided, and the space portion 33 for slow cooling detected by the temperature detection device 38. The internal temperature is output to the control device 39, and the flow control valve 37 is controlled by the control device 39 so that the cooling gas heated in the slow cooling space 33 is discharged from the exhaust port 35. The amount discharged through the passage 36 is adjusted, and the amount of cooling gas introduced into the annealing space portion 33 from the inlet 34 is controlled, whereby the inside of the annealing side muffle 12 in the annealing zone 30 is controlled. The temperature of the metal strip S to be gradually cooled is controlled.

Thus, the metal strip heated in heating zone 20 without lengthening the length of annealing zone 30 in order to sufficiently cool metal strip S in annealing zone 30 as described above. It becomes easy to anneal S in the annealing zone 30 to a suitable temperature.

Here, the flow control valve 37 is provided as the temperature control unit on the side of the exhaust port 35 to ventilate with the rising air flow, but a fan (not shown) is provided as the temperature control unit to ventilate with the forced air flow. The flow rate may be controlled by changing the rotational speed. Also, they may be provided on the inlet 34 side.

Further, in this embodiment, as described above, the muffle 10 is provided in the heating side muffle 11 provided in the heating zone 20 for heating the metal strip S and in the annealing zone 30 for annealing the heated metal strip S. Although what was made to separate the annealing side muffle 12 was used, as shown in FIG. 2, it is made not to separate the muffle 10, and the heating zone 20 which heats the metal strip S and the heated metal strip S are The muffle 10 in the annealing zone 30 to be cooled can also be configured as a single cylinder.

And when muffle 10 is constituted by one cylinder in this way, as shown in FIG. 2, the annealing side support member 31 which provided the upper side flange 10a of said muffle 10 on the upper surface of the annealing band 30. As described above, the guide pipe 41 extends downward from the lower surface of the cooling zone 40, and the cooling side is expandable with the muffle 10 and the guide pipe 41 sealed. It is made to connect by the connecting cylinder 42. As shown in FIG. Here, when the muffle 10 and the guide pipe 41 extended downward from the cooling zone 40 are connected by the cooling side connecting cylinder 42, the upper flange 10 a of the muffle 10 and the cooling side connecting cylinder 42 are connected. And the lower flange 42a of the guide pipe 41 and the upper flange 42b of the cooling side connecting cylinder 42 by bolts (not shown) and the like. Make it connect with.

Moreover, although the example in which the metal strip S is moved upward from the bottom is shown here, if the heating zone 20, the annealing zone 30, and the cooling zone 40 are in order from the upstream side of the moving direction of the metal strip S The moving direction of the metal strip S may be from the top to the bottom, the horizontal direction, or the inclined direction.

10: muffle 10a: upper flange 11: heating side muffle 11a: upper flange 12: slow cooling side muffle 12a: upper flange 12b: lower flange 13: connecting cylinder 13a: lower flange 13b: upper flange 20: heating band 21: heating side support member 22: heat insulator 23: heating space 24: heating device 30: annealing zone 31: annealing side support member 32: insulation 33: annealing space 34: inlet 35: exhaust Port 36: Discharge path 37: Flow control valve (temperature control unit)
38: Temperature detector 39: Controller 40: Cooling zone 41: Guide tube 41a: Lower flange 42: Cooling side connecting cylinder 42a: Lower flange 42b: Upper flange S: Metal strip

Claims (5)

A metal strip is conveyed inside the muffle, which is disposed vertically and contains a process atmosphere gas, and the metal strip moves from the outside of the muffle to the upstream in the moving direction of the metal strip in the muffle. A heating zone for heating the heating strip, an annealing zone for annealing the heated metal strip moving inside the muffle to a position downstream of the heating zone in the moving direction of the metal strip, and the annealing zone A vertical muffle type heat treatment furnace provided with a cooling zone for cooling the annealed metal strip at a position downstream of the metal strip in the moving direction of the metal strip;
An inlet for introducing a cooling gas into the space for slow cooling between the muffle and the annealing zone is provided, and an outlet for discharging the cooling gas heated in the space for slow cooling is provided. A vertical muffle comprising a temperature control unit for controlling the temperature of the metal strip to be gradually cooled in the annealing zone by adjusting the amount of heated cooling gas exhausted through the exhaust port. Heat treatment furnace. The vertical muffle type heat treatment furnace according to claim 1, further comprising: a temperature detection device for detecting a temperature in the space portion for slow cooling between the muffle and the slow cooling zone, for slow cooling detected by the temperature detection device A vertical muffle type heat treatment furnace, characterized in that the temperature control unit is adjusted based on the temperature in the space. The vertical muffle type heat treatment furnace according to claim 1 or 2, wherein the muffle is a heating side muffle provided in the heating zone and an annealing side muffle provided in the annealing zone. A vertical muffle type heat treatment furnace characterized in that the heating side muffle and the annealing side muffle are connected by an expandable connecting cylinder in a sealed state. The vertical muffle type heat treatment furnace according to any one of claims 1 to 3, characterized in that the muffle is attached to the cooling zone in an expandable manner in a sealed state of the muffle. Vertical muffle type heat treatment furnace. 4. The vertical muffle type heat treatment furnace according to any one of claims 1 to 3, wherein the introduction port for introducing a cooling gas into the slow cooling space portion is at a lower side position of the slow cooling zone. A vertical muffle type heat treatment characterized in that the exhaust port for exhausting the cooling gas heated in the space portion for slow cooling is provided at the upper side position of the slow cooling zone than the introduction port. Furnace.

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