JPH0514773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a vertical continuous annealing apparatus for metal strip.

[Conventional technology]

In general, a continuous annealing furnace for brightly annealing a cold-rolled metal strip such as stainless steel is equipped with an annealing furnace 3 and a plurality of cooling devices arranged in multiple stages on the exit side of the top roll 2, as shown in Fig. 3. A vertical continuous annealing apparatus was used in which four groups were arranged. In such a vertical continuous annealing apparatus, the metal strip 1 ascends through the inlet chute 11, reaches the top roll 2, is reversed in its direction of movement from upward to downward, and then enters the annealing furnace 3 where it is heated and further heated. It was cooled by four groups of multiple cooling devices.

In this case, each cooling device 4 blows air or reducing atmosphere gas cooled by a cooler 8 onto the metal strip 1 using a blower 9, as shown in FIG. The reducing atmosphere gas was collected, sent to the cooler 8, cooled again, and used for circulation.

[Problem that the invention seeks to solve]

In the conventional apparatus as described above, the heat of the cooling medium heated by heat exchange with the air or reducing atmosphere gas cooled by the cooler 8 is mostly used because it is too low to be used as an industrial heat source. The problem was that the thermal efficiency of the device was poor.

In addition, in order to increase the threading efficiency (speed) and equipment capacity while annealing as in the past, the length of the annealing furnace and cooling equipment must be increased as one way to increase the throughput of the annealing furnace and cooling equipment. Therefore, the height of vertical continuous annealing equipment has to be high, but generally speaking, the higher the height of vertical continuous annealing equipment, the higher the metal strip size, not only in terms of operation but also in terms of quality. It is difficult to pass through the annealing equipment, which tends to cause various problems, and the construction cost of the equipment also increases, so it is desirable that the height of the vertical continuous annealing equipment be as low as possible.

[Means for solving problems]

The inventors of the present invention have conducted intensive research to solve the above-mentioned conventional problems.The inventors of the present invention have conducted intensive research to solve the above-mentioned conventional problems. If the metal strip is preheated at the entrance chute of the top roll of a vertical continuous annealing machine, which is a space where the metal strip is fed into the machine and is used as a passing path, the heating cost can be significantly reduced. We have found that it is possible to increase the sheet passing efficiency and the equipment capacity, and to improve not only the operational aspects but also the quality of the vertical continuous annealing equipment without increasing the height of the vertical continuous annealing equipment. Thus, a vertical continuous annealing apparatus for metal strips according to the present invention was completed.

That is, in the present invention, a top roll for reversing the moving direction of the metal strip from upward to downward is provided at the top of the entrance chute, and an annealing furnace for annealing the metal strip is provided on the exit side of the top roll, and an annealing furnace for annealing the metal strip after annealing is provided. A group of multiple cooling devices that cool each metal strip by spraying air or reducing atmosphere gas that is cooled by a cooler and circulated by a blower and recovering the air or reducing atmosphere gas that has been blown and heated by the metal strip. in a vertical continuous annealing apparatus for metal strip, which is provided with a plurality of cooling device groups selected from among the plurality of cooling device groups in order of proximity to the annealing furnace and the plurality of cooling device groups. a group of high-temperature blowers that collects air or reducing atmosphere gas heated by the metal strip blown onto the metal strip after annealing from a plurality of cooling device groups selected in order of proximity to the cold annealing; and a group of high-temperature air blowers that collect the recovered high-temperature air. Alternatively, there is a preheating device group that sprays reducing atmospheric gas directly onto the metal strip moving upward at the inlet chute of the top roll to preheat it, and a group of preheating devices that spray cooled air or reducing gas onto the metal strip before annealing. a low-temperature blower that collects atmospheric gas from the lower part of the inlet chute and supplies it to a plurality of cooling devices selected in order of proximity to the annealing furnace; and a plurality of cooling devices selected by the low-temperature blower in order of proximity to the annealing furnace. The present invention provides a vertical continuous annealing apparatus for metal strip, characterized in that it is equipped with a separate cooler for cooling the air or reducing atmosphere gas supplied to the metal strip.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The vertical continuous annealing apparatus for metal strips according to the present invention will be explained in detail below based on the embodiments shown in the drawings.

FIG. 1 is an explanatory vertical cross-sectional view showing the structure of one embodiment of a vertical continuous annealing apparatus for metal strips according to the present invention, and FIG. 2 is an explanatory plan view thereof.

In the drawings, 1 is a metal strip that is continuously annealed by the vertical continuous annealing apparatus for metal strips according to the present invention, and 2 is a metal strip provided at the top of the vertical continuous annealing apparatus for metal strips according to the present invention. This is a top roll that reverses the moving direction of the metal strip 1 from upward to downward through the entrance chute 11, and this top roll 2 is different from the case of conventional vertical continuous annealing equipment for metal strips. Since it is preheated, it is made of highly heat-resistant metal, ceramic, heat-resistant rubber, or asbestos. Reference numeral 3 indicates an annealing furnace, which is provided on the exit side of the metal strip 1 via the top roll 2 provided at the top, for annealing the metal strip 1; Blower 9
A cooling device group that cools the metal strip 1 by blowing air or reducing atmosphere gas through the metal strip 1, and collects the air or reducing atmosphere gas that has been blown and heated by the metal strip 1 for cooling by the cooler 8. be. 4' is a plurality of cooling device groups selected in order of proximity to the annealing furnace 3 from among the plurality of four cooling device groups conventionally used in a multi-stage manner as described above, and is used to cool the metal strip 1 immediately after annealing. The metal strip 1 is cooled by applying air or reducing atmosphere gas from the lower part of the inlet chute 11 by a low-temperature blower 7, which will be explained later, and the air or reducing atmosphere gas heated by the metal strip 1 is then blown onto the metal strip 1. This is a group of cooling devices recovered by the high temperature blower 5 described in . 5 is a cooling device 4' group which mainly collects the air or reducing atmosphere gas that is blown onto the annealed metal strip 1 and heated by the metal strip 1; 6 is a group of high temperature blowers that collect the recovered high temperature air or reducing atmosphere gas; A preheating device group 7 sprays atmospheric gas onto the metal strip 1 moving through the inlet chute 11 of the top roll 2 to preheat it, and 7 is air or reducing atmosphere that is cooled by being blown onto the metal strip 1 before annealing by the preheating device group 6. a low-temperature blower 10 for collecting gas from the lower part of the inlet chute 11 and supplying it to the cooling device 4';
is a cooler that cools the air or reducing atmosphere gas from the lower part of the inlet chute 11 that is supplied to the cooling device 4' group by the low temperature blower 7, and the solid arrow in the drawing indicates the movement of the air or reducing atmosphere gas. , and the dashed-dotted arrows indicate the movement of the cooling medium that cools the air or reducing atmosphere gas. Generally, the temperature of the air or reducing atmosphere gas recovered by the four groups of conventional cooling devices depends on the type and internal structure of the vertical continuous annealing device itself, each shape, each forming material, each arrangement position, and each dimensional capacity. or heating means for annealing the metal strip 1, its structure, etc.
The threading method of the metal strip 1 (threading level, threading direction), the annealing conditions of the metal strip 1 (annealing temperature conditions, threading speed...), the processing capacity of the cooling device 4 group, the installation location, the cooling device 4 The cooling means (cooler 8, blower 9, cooling medium, etc.) accompanying the group, its processing capacity, the type, component ratio, and concentration of the air or reducing atmosphere gas itself in the entire interior of this device and in that part, etc. It varies greatly depending on the flow rate, the airtightness of the equipment itself (sealing area and means of sealing), etc., but if all these conditions and conditions are almost the same, the installation position of the 4 cooling equipment groups has a large influence, and the annealing The closer the recovered air or reducing atmosphere gas is from the cooling device 4 to the furnace 3, the higher the temperature. Specifically, in the cooling device 4 directly below the annealing furnace 3, the temperature of the air or reducing atmosphere gas is 300°C.
However, since the temperature may not rise to 50°C in the lower cooling device 4, it is desirable that the temperature that can be used for preheating the metal strip 1 is 100°C or higher, and that the temperature of the metal strip 1 exiting the vertical continuous annealing apparatus is 100°C or higher. Since the temperature of the cooling device must be lowered to near normal temperature, it is preferable in the present invention that at least the lowermost cooling device 4 has the same structure as the conventional device as shown in FIG. In addition, in order to increase the heat transfer effect, high temperature air or reducing atmosphere gas is supplied to the preheating device 6 near the top roll 2.
It is desirable to supply

The operation of continuously annealing the metal strip 1 using the vertical continuous annealing apparatus for metal strips according to the present invention constructed as described above will now be described.

The metal strip 1 loaded into the device of the present invention is
First, while ascending toward the top roll 2 via the inlet chute 11, the top roll 2 at the top is preheated to a temperature close to that temperature by high-temperature air or reducing atmosphere gas blown from a plurality of preheating devices 6 groups. The direction of movement is reversed from upward to downward, and the material is charged into the annealing furnace 3, heated, further raised in temperature, and annealed. After that, the cooling device 4' group and the cooling device installed at least at the bottom are heated. It is cooled according to desired conditions by low-temperature air or reducing atmospheric gas blown from each of the four groups.

At this time, according to the apparatus of the present invention as shown in FIG.
The relatively low-temperature air or reducing atmosphere gas recovered from the lower part of the cooler by the low-temperature blower 7 is sent to the cooler 10.
The metal strip is further cooled by the annealing furnace 3, and sent to a plurality of cooling devices 4' selected in order of proximity to the annealing furnace 3. From these cooling devices 4', the metal strip 1, which is in a high temperature state after annealing, is sprayed to cool the metal strip. The air or reducing atmosphere gas heated by the metal strip 1 is collected from the cooling device 4' group by high temperature blower 5 groups and sent to the preheating device 6 group, where it is fed into the top roll 2. It is sprayed onto the moving metal strip 1 at the top of the side chute 11. In this case, the high temperature blower 5 group can also be implemented as one high temperature blower 5. The blown air or reducing atmosphere gas flows to the lower part of the inlet chute 11 of the device of the present invention while gradually lowering its temperature due to heat transfer to the metal strip 1, and is again collected by the low temperature blower 7 and cooled by the cooler 10. It is then supplied with four groups of multiple cooling devices.

[Effect]

If the vertical continuous annealing apparatus for metal strips according to the present invention as described above is used, as described above, the air or reducing atmosphere gas is in a high temperature state after annealing and in a low temperature state close to room temperature before annealing. Since the metal strip is alternately blown onto the metal strip, collected, and used for circulation, conventional heat exchange with air or reducing atmosphere gas is blown onto the metal strip, which is heated by the metal strip, and then collected and cooled by the cooler. Since the heat of the coolant heated by the heat source is too low for an industrial heat source, the heat that would otherwise be completely unused and wasted can be used to preheat the metal strip, improving the thermal efficiency of the device itself and saving energy. Furthermore, the air or reducing atmosphere gas after being blown onto the metal strip by this preheating device flows in the opposite direction to the direction of movement of the metal strip, resulting in a lower temperature than the lower part of the inlet chute of the device of the present invention. Since the metal strip curves out, the preheating efficiency of the metal strip can be further increased.

〔Effect of the invention〕

As described in detail above, the vertical continuous annealing apparatus for metal strips according to the present invention can be used in a manner different from the conventional one by circulating air or reducing atmosphere gas as described above for cooling the metal strip after annealing. Since the unused sensible heat of the metal strip can be used effectively, the thermal efficiency of the equipment itself is increased and the cost of heating the metal strip can be significantly reduced.The height of the annealing furnace is also reduced because the metal strip is preheated. Even at a low temperature, the ability to heat the metal strip is sufficient, so it is possible to increase the throughput efficiency of the metal strip and increase the processing capacity of the device without increasing the overall height of the vertical annealing furnace for metal strip. becomes.

In addition, as the overall height of the device increases and the thickness of the metal strip annealed in the device becomes thinner and the width of the metal strip becomes wider, the metal strip passing through the device becomes lighter and weaker, like paper. As the metal strip bends, it easily loses its shape and cannot easily maintain its straightness and flatness, making it difficult to control the tension of the metal strip itself. It is extremely difficult to thread metal strips at high speed without causing contact scratches or scratches, but this difficulty can be alleviated by suppressing the increase in the overall height of the device. It can greatly help and contribute to solving the problem.

Furthermore, as a cooling device, conventionally a high-performance external cooler is used to cool the high-temperature air or reducing atmosphere gas to the initial temperature by cooling the metal strip, which is in a high-temperature state immediately after exiting the annealing furnace. However, in the device of the present invention, after the metal strip has been preheated by the preheating device, a cooler with low performance that cools the relatively low temperature air or reducing atmosphere gas to the initial temperature can be used. It has various advantages such as being able to cool the strip smoothly, and is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is an explanatory vertical cross-sectional view showing the structure of one embodiment of the vertical continuous annealing apparatus for metal strips according to the present invention, FIG. 2 is an explanatory plan view of the same, and FIG. FIG. 4 is an explanatory vertical cross-sectional view showing the structure of one embodiment of the continuous annealing apparatus, and FIG. 4 is an explanatory plan view thereof. 1...metal strip, 2...top roll,
3...Annealing furnace, 4...Cooling device, 4'...Cooling device, 5...High temperature blower, 6...Preheating device, 7...
Low temperature blower, 8...Cooler, 9...Blower, 10
...Cooler, 11...Inlet chute.

Claims (1)

[Claims] 1 Metal strip 1 on the top of the inlet chute 11
A top roll 2 is provided for reversing the moving direction of the top roll from upward to downward.
an annealing furnace 3 for annealing the metal strip 1 on the exit side of the
Then, air cooled by a cooler 8 and circulated by a blower 9 or reducing atmosphere gas is blown onto the metal strip 1 after annealing to cool the metal strip 1, and the blown air is heated by the metal strip 1. Alternatively, in a vertical continuous annealing apparatus for metal strips, which is provided with a plurality of four groups of cooling devices for recovering reducing atmospheric gas, a plurality of four groups of cooling devices are selected from among the four groups of cooling devices in order of proximity to the annealing furnace 3. The plurality of cooling devices 4' groups and the plurality of cooling devices 4 groups blow air or reducing atmosphere gas onto the annealed metal strip 1 and heated by the metal strip 1, and the plurality of cooling devices 4' groups 5 groups of high-temperature blowers that collect air or reducing atmosphere gas from the top roll 2; Metal strip 1 before annealing with 6 groups of preheating devices
a low-temperature blower 7 that collects cooled air or reducing atmosphere gas from the lower part of the inlet chute 11 and supplies it to the plurality of cooling devices 4'; A vertical continuous annealing apparatus for metal strip, characterized in that it is equipped with a cooler 10 for cooling air or reducing atmosphere gas supplied to the metal strips.