JPH042730A - Continuous annealing apparatus - Google Patents

Abstract

PURPOSE:To easily execute uniform heating and cooling to a metal to be annealed with high thermal efficiency by heating and cooling the metal to be annealed in liquid metal and arranging mechanism forcedly circulating the liquid metal in cooling zone to heating zone. CONSTITUTION:The metal strip 22 is passed through an inlet inactive zone 29, heating zone 30, first soaking zone 31, slow cooling zone 32, first cooling zone 33, second soaking zone 34, second cooling zone 35, outlet inactive zone 36 and cooling and washing zone 37 in a furnace 21 in order with a conveying device 28 execute the continuous annealing. Then, the heating and cooling to the metal strip 22 are executed with the liquid metal 40 (e.g. Na) in a heating vessel 41a and cooling vessels 41b, 41c. Further, the liquid metal 40 in the cooling vessel 41c is forcedly circulated to the cooling vessel 41b through an overflow tube 46c, overflow tank 47c and circulating piping 51c, and the liquid metal 40 in the cooling vessel 41b is forcedly circulated to the heating vessel 41a through an overflow tube 46b, overflow tank 47b and circulating piping 51b. Then, the liquid metal 40 in the heating vessel 41a is fed to the cooling vessel 41c with the same way.

Description

Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention relates to a continuous annealing apparatus for continuously annealing cold rolled steel plates, copper plates, AI plates, etc. This invention relates to a continuous annealing device with improved cooling means.

(Prior Art) First, an example of a temperature change pattern required for general continuous annealing of cold rolled steel plates and the like will be explained based on FIG. 4.

The temperature change pattern changes over time in heating area A1
It is divided into a secondary isothermal (soaking) zone B1, a first cooling zone C1, a second isothermal (soaking) zone, and a final cooling zone E.

Among these, the primary cooling zone C may be further divided into a slow cooling zone Ca with a slow cooling rate and a rapid cooling zone Cb with a fast cooling rate. The isothermal holding time in the first isothermal area B is approximately 30 seconds to 90 seconds.
Seconds. The isothermal holding time in the second isothermal region is about 1 minute in the short case, and about 3 to 5 minutes in the long case.

Further, the temperature of the first isothermal region B needs to be higher than the recrystallization temperature of the metal to be annealed, and is often controlled to a value of about 620°C to 850°C. However, depending on the material to be annealed, 9
In some cases, the temperature may be set to a value of 20°C to 1000°C or higher.

The temperature in the second isothermal region is often controlled to a value of about 350°C to 450°C. However, depending on the material to be annealed, a slight cooling rate due to heat radiation and slow cooling may be allowed in both the first and second isothermal regions.

As a means for realizing such a temperature change pattern, a continuous annealing apparatus shown in FIG. 5 is conventionally known.

In other words, this continuous annealing apparatus uses a steel plate as the metal to be annealed.
A closed furnace body 4 having an inlet 2 and an outlet 3 is provided.

In the furnace body 4, there is provided a conveyance device, for example, a plurality of rollers 5 disposed above and below, which continuously conveys the steel plate 1 in a vertically meandering manner from the population 2 side toward the exit 3 side.

The internal space of the furnace body 4 is divided into a plurality of chambers by grooves 6 whose ceilings are depressed inward, partition plates, etc., and thermally isolated from each other, as shown in FIG. Corresponding to the temperature change pattern, from the inlet 2 side to the outlet 3 side, a heating area 7, a primary isothermal area 8, a slow cooling area 9a, a primary cooling area 9b, and a secondary isothermal (soaking) area 10 are arranged. , the secondary cooling region 11, etc. are sequentially formed.

A large number of radiant tubes 12 are installed in the heating area 7 along the conveyance path of the steel plate 1.
Combustion gas flows in the tube 2 and heats up the surface of the tube.

Further, each of the cooling regions 9a, 9b, 11 is provided with one or more cooling nozzles 13a, 13b, 14 along the conveyance path of the steel plate 1, which eject water or gas in the form of mist.

In this continuous annealing apparatus, the steel plate 1 first enters the heating area 7 in the furnace body 4, and is then heated by heat from the radiant tube 12 while being guided in a meandering manner up and down by the rollers 5. The temperature is raised to a predetermined temperature (area A in FIG. 4).

After this temperature rise, it enters the first isothermal region 8 and is maintained at that internal temperature for a predetermined time (region B in FIG. 4).

Next, it enters the slow cooling region 9a and is slowly cooled to a predetermined temperature by a coolant such as gas or water sprayed from the cooling nozzle 13a, or by natural cooling (
Fig. 4 Ca area).

Thereafter, the steel plate 1 enters the first cooling region 9b, where it is rapidly cooled to a predetermined temperature by a coolant such as gas, water, or spray water sprayed from the cooling nozzle 13b (region Ca in FIG. 4). Enter the isothermal region 10.

After being maintained at a predetermined temperature for a predetermined time in the isothermal region 10 (fourth cooling region), it enters the second cooling region 11, where it is cooled by the coolant sprayed from the cooling nozzle 14.
It is cooled to near room temperature (region E in FIG. 4) and sent out from the furnace body 4.

(Problem to be Solved by the Invention) However, such a conventional continuous annealing apparatus has a problem of low thermal efficiency.

That is, in the conventional continuous annealing apparatus, combustion gas in the radiant tube 12 is used as a heating means, and heat is transmitted to the steel plate 1 mainly by radiation.

Moreover, in order to prevent a large amount of corrosive combustion gas from being released into the steel plate 1 and the furnace body 4 when the radiant tube 12 is damaged, the gas pressure inside the radiant tube 12 is always lower than the gas pressure inside the furnace body 4. Since combustion is performed under pressure, the heat transfer coefficient is poor, a large number of radiant tubes 12 are required, and the heating area is also long, resulting in an increase in the size of the entire device. In addition, in order to increase the heat transfer efficiency by radiation as much as possible, the surface temperature of the radiant tube 12 is made as high as possible, so that the radiant tube 12 is subject to severe corrosion and wear and tear, and its lifespan is shortened.

Further, since the radiant tube 12 is long, the temperature of the combustion gas passing through the tube differs between the inlet and outlet of the radiant tube 12, making it difficult to uniformly heat the steel plate 1 in the width direction.

Furthermore, the high temperature combustion waste gas is not used very effectively, resulting in a large amount of heat loss, and the generated CO2 may cause environmental pollution.

Furthermore, as a cooling means in the primary cooling zone 9b, a coolant such as gas or water is sprayed.
In this type of gas cooling, the cooling rate is slow and this cooling area needs to be long. In addition, when the cooling rate in the quenching area cb is slow, it is necessary to There is a problem that the area of the secondary isothermal region needs to be lengthened, which increases the size of the entire device.

Furthermore, when cooling with water or the like, the water sprayed on the surface of the steel plate 1 boils, resulting in uneven cooling, which tends to cause temperature differences in the width direction of the steel plate 1.

As a result, a steel plate waving phenomenon occurs due to the difference in elongation, which may lead to breakage.

Furthermore, when cooling with water, etc., it is difficult to control the cooling temperature, often resulting in supercooling, and in some plants, a reheating zone is provided between the quenching zone cb and the second isothermal zone. be. Since radiation heating and gas/water cooling are used, the controllable range of heating and cooling rates is relatively narrow, and the response of temperature control inside the furnace is also poor. When steel plates 1 of different widths are processed continuously, there is a problem in that the temperature rise and fall is insufficient and the product quality deteriorates.

Therefore, the present invention was made in consideration of these circumstances, and its purpose is to have low heat loss, high heat transfer performance, uniform heating and cooling effects, and control over a wide range. The quality of annealed steel sheets can be improved by heating and cooling speeds,
It is an object of the present invention to provide a continuous annealing device that is effective in downsizing the entire device and causes less environmental pollution due to the release of CO2, etc.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention is configured as follows.

In other words, the present invention provides a conveying device that continuously conveys the metal to be annealed in a meandering manner up and down from the inlet side to the outlet side in a closed furnace body having an entrance and exit for the metal to be annealed. In a continuous annealing apparatus, the metal plate to be annealed passing through the furnace body is divided into a heating area, a soaking area, and a cooling area, which are thermally isolated from each other, and the metal plate to be annealed is continuously annealed. A liquid metal container for heating and cooling the metal to be annealed by immersing it in the liquid metal is installed in each area, and these liquid metal containers are sequentially connected in series by piping. An overflow tank is provided to accommodate the overflowing liquid metal in the container, and a heat exchanger and a pump are provided downstream of each overflow tank, and the liquid metal is transferred to the cooling area through the piping. A closed loop is formed for forced circulation from the liquid metal container in the heating area to the liquid metal container in the heating area.

(Operation) The metal to be annealed enters the closed furnace body from the entrance, and is conveyed by the conveying device toward the outlet while meandering up and down.

During this transportation, the metal to be annealed is successively heated, soaked, and cooled as it passes through a heating area, a soaking area, and a cooling area, and is annealed.

In the heating region and the cooling region, the metal to be annealed is directly immersed in the liquid metal in each liquid metal container to perform heating and cooling, respectively, resulting in extremely high thermal efficiency and easy uniform heating and cooling. It is possible to mass-produce high-quality products with low risk of breakage of the annealed metal.

In addition, since the liquid metal circulates through piping from the cooling area to the liquid metal container in the heating area, the heat given to the metal to be annealed in the cooling area can be recovered in the heating area, further improving thermal efficiency. This allows for significant energy savings.

Therefore, it is possible to further downsize the continuous annealing apparatus.

Furthermore, since the metal to be annealed is heated and cooled while flowing the liquid metal as a heat medium, the temperature of each part can be easily controlled by controlling the flow rate of the liquid metal.

Therefore, according to the present invention, a product of good quality can be obtained at low cost and through a simple manufacturing process.

(Example) Examples of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention,
In the figure, a continuous annealing device 20 performs an annealing action based on the temperature change pattern shown in FIG. 4 described above.

The continuous annealing device 20 includes a metal to be annealed (hereinafter referred to as metal plate) 2 such as a cold rolled steel plate at each end of a horizontally long closed furnace body 21.
An inlet 23 for introducing 2 and an outlet 24 for discharging it are provided, respectively.

An inlet seal roll 25 and an outlet seal roll 26 are provided at the population 23 and the outlet 24, respectively, and the metal plate 22
While maintaining sealing properties within the closed space of the furnace body 21, it is possible to continuously enter and exit the furnace body 21.

Although the configuration of each seal roll 25, 26 is not shown in detail,
A spring-biased seal plate is attached to the gap between the outer wall of the furnace body 21 and the outer circumferential surface of the roll to seal the exits 23 and 24.

Inside the furnace body 21, a metal plate 22 is inserted from the inlet 23 side to the outlet 24.
A conveying device 28 is provided which has a large number of rollers 27 that meander upwardly and downwardly toward the side and convey continuously.

The interior space of the furnace body 21 is divided into a plurality of airtight and thermally insulated regions. That is, corresponding to the temperature change pattern shown in FIG. 32. Primary cooling area 3
3. It is divided into a second isothermal (soaking) area 34, a second cooling area 35, an inert area 36, and a cooling cleaning area 37.

Each of these regions 29 to 37 is partitioned by a plurality of vertical partition walls 38 and horizontal partition walls 39 .

The heating region 29 is provided with a heating tank 41a as a heating means, which is a liquid metal container in which the metal plate 22 is directly immersed in, for example, liquid metal sodium 40 and heated.

This heating tank 41a has a cylindrical shape with an open top and a bottom.
Liquid metal sodium 40 is accommodated with a free liquid level.

This heating tank 41a has an inlet 42a for the liquid metal sodium 40 and an overflow outlet 43 on its mutually opposing side walls.
A is provided.

Further, the heating tank 41a has an inlet seal roll 39a and an outlet seal roll 3 attached to the horizontal partition wall 39 that closes the upper end of its opening.
9b, and the lower roller 27 of the conveying device 28 is housed inside the heating tank 41a.

The lower end of the lower partition wall 38a of the vertical partition wall 38 located above the lower roller 27 is coupled to the lower roller 27.1. This lower partition wall 38a partitions the inside of the heating tank 41a into an inlet 42a for the liquid metal sodium 40 and an overflow outlet 43a.

This prevents the liquid metal sodium 40 that has flowed into the heating tank 41a from the inlet 42a from directly mixing with the overflow outlet 43a, and allows efficient heating.

Therefore, the metal plate 22 enters the heating tank 41a from the inlet seal roll 39a to the inlet 42a side, passes through the liquid metal sodium 40 and is heated, and the lower roller 2
7 to the overflow outlet 43a side, and further exits into the first isothermal region 31 from the outlet seal roll 39b.

In addition, the heating tank 41a fills the space 44a above the free liquid surface of the metal sodium 40 with a cover gas made of an inert gas such as Ar from the gas system piping 44 to prevent the liquid metal sodium 40 from deteriorating. are doing.

On the other hand, in the first and second cooling areas 33.35, a first cooling tank 41b1 which is a liquid metal container and a second
A secondary cooling tank 41c is provided respectively.

These primary and secondary cooling tanks 41b and 41c cool the metal plate 22 by directly immersing it in the low-temperature liquid metal sodium 40, and the parts common to the heating tank 41a are shown in FIG. , are given the same reference numerals, and the description thereof will be omitted.

These heating tanks 41a and primary and secondary cooling tanks 41b
, 41c, the inlet inactive region 29 and the first isothermal region 3 are separated in a thermally insulated state.
1. Slow cooling region 32, second isothermal region 34, inert region 3
6 and the cooling cleaning area 37 are each opened at the open end of a gas system pipe 44 for supplying an inert gas, and the inert gas is supplied to prevent oxidation of the metal plate 21 and also to prevent the metal plate 21 from oxidizing depending on the gas temperature. It is designed to have a uniform heat effect.

Further, a gas cooler 45 connected to a cooling gas pipe 45a that supplies cooling gas is provided in the slow cooling region 32,
This gas cooler 459 slowly cools the metal plate 22 by spraying cooling gas onto the metal plate 22 from a large number of ejection holes.

The cooling gas ejected into the slow cooling region 32 is recovered to a gas source by a gas recovery pipe 45b.

Then, the heating tank 41a and the primary and secondary cooling tanks 41b,
41c are sequentially connected in series through the large circulation piping 46, and the second
The heating tank 4 passes from the secondary cooling tank 41c to the primary cooling tank 41b.
Liquid metal sodium 40 is forcibly circulated toward 1a. That is, each overflow outlet 42a, 4 of the heating tank 41a and the primary and secondary cooling tanks 41b, 41c
2a.

42a includes each over 70- which is a part of the general circulation pipe 46.
Each overflow tank 47a, 47b, 47cl: is connected via pipes 46a, 46b, 46c.

Each overflow tank 47a, 47b, 47C is a small circulation pipe 48a that circulates the liquid metal sodium 40 in each overflow tank 47a, 47b, 47c, respectively.
, 48b, 48c are provided, and each small circulation pipe 48a,
48b, 48cl:l;! Liquid metal refining device 49a, 4
9b, 49c and pumps 50a, 50b, 50c are interposed, respectively, and impurities mixed in the liquid metal sodium 40 are removed and purified by the respective liquid metal purifiers 49a, 49b, 49c.

Next, the general circulation piping 46 will be explained.

The general circulation pipe 46 is the overflow pipe 46a to 46c.
and circulation pipes 51a to 51c.

That is, the large circulation piping 46 connects the circulation piping 51a to 51c to the heating tank 41a1, the primary cooling tank 41b, and the secondary cooling tank 41b, 41c.
c each inlet 42a, 42a, 42a and each over 70
-Tanks 47a, 47b.

47c, and each tank 41a to 41
It constitutes a closed loop that circulates the liquid metal sodium 4o in c in the direction of the arrow in the figure.

Further, in the middle of each circulation pipe 51a, 51b, 51c, circulation pumps 52a, 52b, 5, which are electromagnetic pumps, for example, are provided.
2c, a heater 53a and coolers 53b, 53c, respectively, and the liquid metal sodium 40 in the heating tank 41a, primary and secondary cooling tanks 41b, 41c is transferred from the secondary cooling tank 41c. Heating tank 41 via primary cooling tank 41b
The liquid metal sodium 4o is forcibly circulated toward a, and during the circulation, the liquid metal sodium 4o is appropriately heated or cooled to a predetermined temperature.

That is, the heater 53a is interposed in the middle of the circulation pipe 51b connected to the inlet 42a of the heating tank 41a and the outlet side of the overflow tank 47b, and is connected to the liquid metal sodium 4o.
is heated to a predetermined temperature.

The coolers 53b and 53c are connected to circulation pipes 51 connected to the inlets 42a and 42a of the primary and secondary cooling tanks 42 and the outlets of the overflow tanks 47b and 47c.
b and 51c, respectively, to cool the liquid metal sodium 4o to a predetermined temperature.

The heating tank 41a and the primary and secondary cooling tanks 41
b, the bottom of 41c and each overflow tank 47a~
47c are respectively connected to the surge tank 55 via each drain pipe 54, and each drain valve 54 is provided with a valve 54a.

Further, gas supply pipes 56 for supplying a predetermined gas are connected to each overflow tank 47a to 47c and surge tank 55, and the valve opening of the control valve installed in these gas supply pipes 56... The liquid metal sodium 40 can be charged and drained into the surge tank 55 by adjusting the pressure of the supplied gas by adjusting the pressure and adjusting the opening degree of the drain valve 54a.

In FIG. 1, reference numeral 56 is a water jet cooling device that sprays water or atomized water onto both sides of the steel plate 21 in the cooling cleaning area 37 to cool it, and the waste water and the like are discharged to the drain system 57. Ru.

Next, the operation of this embodiment will be explained.

First, the steel plate 22 which is an object to be annealed is placed on the inlet seal roll 2
5 into the inlet inactive area 29 within the furnace body 21.

The gas pressure in this inert inert region 29 is kept higher than the pressure outside the furnace body 21 and the gas pressure in the cover gas space 44a in the heating tank 41a. This prevents outside air from entering the furnace body 21.

In addition, by making the gas pressure higher than the gas pressure in the cover gas space 44a in the heating tank 41a, as the vapor or mist of the liquid metal sodium 40 in the heating tank 41a moves, the inert area 29 and the furnace It prevents leakage outside the body 21.

Next, the steel plate 22 enters the heating tank 41a provided at the bottom of the furnace body 21 through the inlet seal roll 39a of the lid 39, and is further conveyed by the rollers 27 and immersed in the high temperature liquid metal sodium 40. It is immersed and heated to a predetermined temperature.

After that, the steel plate 22 exits the heating tank 41a, enters the gas space of the first isothermal region 31 kept at a high temperature through the exit seal roll 39b, and is repeatedly raised and lowered by the upper and lower rollers 27. It is kept isothermal for a predetermined period of time.

The gas pressure in this first isothermal region 31 is also kept higher than the pressure in the cover gas space 44a in the heating tank 41a, and the vapor and mist of the liquid metal sodium 40 enters through the exit seal roll 39b as the inert gas moves. It prevents you from doing it.

Similarly, the gas pressure in the cover gas spaces 44b, 44c in the first and second cooling tanks 41b, 41C is adjusted to The gas pressure is always kept lower than the gas pressure of the liquid metal sodium 40 to prevent the vapor and mist of the liquid metal sodium 40 from diffusing into the furnace body 21.

The steel plate 22 is then subjected to isothermal treatment in the first isothermal region 31.
then enters the slow cooling region 32 where the gas cooling device 4
It is slowly cooled at a predetermined slow cooling rate by the cooling gas ejected from 5.

After this slow cooling, the steel plate 22 enters the next primary cooling tank 41b, is immersed in the low temperature liquid metal sodium 40 filled therein, is immersed, and is rapidly cooled at a predetermined rapid cooling rate. Ru.

Furthermore, after the steel plate 22 is rapidly cooled, it enters the gas space which is the second isothermal region 34 from the first cooling tank 41b, and here,
It is maintained in an isothermal state for a predetermined period of time.

Thereafter, the steel plate 22 enters the secondary cooling tank 41c, is immersed in the low-temperature liquid metal sodium 40 filled therein, and is cooled to a predetermined temperature close to room temperature.

Next, the steel plate 22 passes through the inert area 30 from the exit seal roll 39b, and then enters the cooling cleaning area 37, where it is cooled to room temperature by the water jet cooling device 56, and at the same time, the surface of the steel plate 22 is The metallic sodium and impurities adhering to the water are washed away.

After that, the copper plate 22 is transferred from the outlet seal roll 26 to the furnace body 2.
1 to be carried outside.

Next, the circulation of liquid metal sodium 40 will be explained.

The liquid metal sodium 40 flowing into the secondary cooling tank 41c is cooled to, for example, 200° C. or lower or 150° C. or lower in the cooler 53c before flowing into the inlet port 41c.
It flows in from the central partition wall 38a (on the right side in the figure) and descends while exchanging heat (cooling) with the steel plate 22.

Then, the liquid metal sodium 40 reverses to the overflow outlet 43a side below the central roller 27 in the second cooling tank 41c, rises, further exchanges heat with the steel plate 22, and flows into the second cooling tank 41c. It becomes hotter than when it entered, and flows out from the overflow outlet 43a, through the overflow pipe 46C, and into the overflow tank 47c.

Liquid metal sodium 4 in overflow tank 47c
0 is pressurized by the pump 50c and passes through the liquid metal purification device 49c of the small circulation pipe 48c, and becomes liquid metal sodium 4.
Impurities in 0 are removed.

Further, the liquid metal sodium 40 is pumped up by a circulation pump 52c consisting of an electromagnetic pump, cooled to a predetermined temperature by a cooler 53b, and sent into the primary cooling tank 41b from the inlet 42a.

As described above, the liquid metal sodium 40 cools the steel plate 22 while descending and rising between the partition wall 38a of the primary cooling tank 41b and receives heat.
The water flows out from the overflow pipe 46b on the outlet side of the pipe b and enters the overflow tank 47b.

After this, as in the previous step, the pressure is increased by the circulation pump 52b and heated by the heater 53a, and then it flows into the heating tank 41a from the inlet 42a.

Here, as before, the liquid metal sodium 40 is applied to the partition wall 3.
While descending and rising between the steel plate 8a and the steel plate 22, it is heated while being cooled, and enters the overflow tank 47a through the overflow pipe 51a.

From here, the liquid metal sodium 40 pumped up by the circulation pump 52a passes through the circulation pipe 51a, is cooled by the cooler 53c, and is again pumped into the secondary cooling tank 41.
Return to c.

Therefore, each overflow pipe 46a provided at the liquid level position allows the liquid metal sodium 40 to flow out from the heating tank 41a and the primary and secondary cooling tanks 41b and 41c.
Each overflow tank 47a~ by 46b, 46c
47c, each tank 41a to 4
The liquid level of the liquid metal sodium 40 in 1c is always kept constant, and impurities floating on the liquid level are always discharged into each overflow tank 47a to 47c, and each liquid metal purification device 48a to 48c provided here Can be purified.

In addition, liquid metal sodium 40 in each tank 41a to 41c
The gas spaces 44a to 44C above the free liquid level have an exit and inlet sealing roll 39a, 39b, . . . with a sealing function.
A closed space is formed by the lid 39, the partition wall 38a, and the side walls of various types 41a to 41c, and the gas pressure and atmospheric conditions can be controlled by controlling each gas supply system 44.

Furthermore, it goes without saying that the gas pressure and atmospheric conditions of each of the other gas spaces can be similarly controlled.

And each tank 41a-41c1 circulation piping 51a-51c
In order to first supply the liquid metal sodium 40 to the overflow tanks 47a to 47a, etc., the liquid metal sodium 40 is melted by a heater (not shown) in the surge tank 55, and the liquid metal sodium 40 is supplied to each overflow tank 47a through each drain pipe 54 by adjusting each gas pressure.
A predetermined amount can be sent to 47c and various types 41a to 41c.

Needless to say, heaters are installed in each of the tanks 41a to 41C of the liquid metal tank 40, the circulation pipes 51a to 51c, etc., as necessary.

In addition, the rollers 27 in each tank 41a to 41C and the partition wall 3
8a is configured to be movable in the vertical direction in consideration of ease of initial setting of the steel plate 22 and setting after the steel plate 22 is broken.

In addition, as shown in FIG. 2, in order to improve the heat exchange performance between the liquid metal sodium 40 and the steel plate 22 in each tank 41a to 41C, a partition wall 38a in each tank 41a to 41c is installed.
Insert dummy blocks 60 and 61 around the area and on the inner bottom,
The flow path of the liquid metal sodium 40 may be regulated to increase the flow rate and prevent the occurrence of a stagnation area, thereby improving the heat exchange performance. One dummy block 60 may be configured to be detachable from the partition wall 38a.

Furthermore, the liquid metal sodium 4 attached to the surface of the steel plate 22
0, the gas space 44 on the outlet side of the steel plate 22
It is also possible to provide a gas injection device 62 for spraying an inert gas onto the steel plate 22 at portions a to 44c.

In addition, as a backup, the overflow outlet 4 of the steel plate 22 is
A sealed space 64 is formed above the lid 39 of 3a by the upper lid 63 and the partition wall 38a, and within the sealed space 64 is a heating device, such as induction heating, for heating and evaporating the steel plate 22 and attached sodium. A device 65 is provided.

Furthermore, a gas injection device 66 is provided for spraying an inert gas onto the steel plate 22 in order to promote the evaporation of metallic sodium.

Inert gas controlled at a predetermined temperature is supplied to these gas injection devices 62, 66 from a gas supply system 67, 68, and the vapor or mist of metallic sodium evaporated and removed from the steel plate 22 is converted into vapor (not shown). The gas may be collected by a gas system 69 or a gas supply system 44 equipped with a trap or a mist trap device.

Further, as shown in FIG. 3, both inner surfaces of the wall surfaces 70 in each tank 41a to 41C and the dummy block 6 shown in FIG.
A plurality of pairs of left and right flow path partition plates 71a and 71b are fixed to the outer surface of 0 at a required pitch in the vertical direction, and the liquid metal sodium 4o flows along the inner wall surface as shown by the arrows in the figure. It may be configured to meander.

According to this, by making the liquid metal sodium 40 meander, it is possible to uniformly raise and lower the temperature in the width direction of the steel plate 22 as well.

In the above embodiments, liquid metal sodium 4o was used as a heat medium for heating and cooling, but the present invention is not limited to this (for example, liquid metal lithium or Na
K may be used as a heat medium.

In other words, liquid metal sodium 4o has a melting point of approximately 98°C.
The boiling point is approximately 881°C, and it is difficult to cool the steel plate 22 to 98°C or lower in the secondary cooling tank 41c, and it is not possible to heat the steel plate 22 to 881°C or higher at normal pressure in the heating tank 41a. Na.

However, the melting point of metallic lithium is about 180°C, but the boiling point is 1342°C, so it is convenient for annealing materials that require high temperatures, and NaK has a boiling point of 785°C, but a melting point of -12,6°C. ℃, so it is a useful liquid metal when it is desired to cool down to room temperature by cooling only the secondary cooling tank 41c. It is also possible to use bismuth lead.

Further, in the embodiment described above, the configuration following the temperature change pattern shown in FIG. 4 was explained, but the present invention is not necessarily limited to this, and may be
- Number of 41c, coolers 53b, 53c and heater 53
It goes without saying that various temperature change patterns can be accommodated by mainly changing the capacity of the piping between the a1 tanks 41a to 41c.

In addition, in order to recover and effectively utilize inert gas such as argon (Ar), each of the seal rolls 25 and 26 at the outlet and inlet are configured in a double layer, and a gas recovery pipe provided between them is used to collect the gas from inside the furnace body 21. It may be configured such that the leaking inert gas such as A+ is sucked and recovered together with air, separated, and then sent to the furnace body 21 again.

〔Effect of the invention〕

As explained above, the present invention not only makes it possible to easily realize a temperature change pattern based on a typical annealing process, but also allows the metal to be annealed to be heated or cooled by directly immersing it in a liquid metal. Therefore, uniform heating and cooling of the metal to be annealed can be easily performed with extremely high thermal efficiency, and safe annealing can be performed without fear of breakage, making it possible to produce high-quality products.

Furthermore, since liquid metal has a very high heat transfer coefficient, the heating area and cooling area can be significantly reduced compared to conventional ones, and the device configuration can be made smaller.

Moreover, the heat applied to the metal to be annealed in the cooling region can be easily recovered in the heating region, which increases the heat transfer coefficient within the layer, making it possible to significantly save energy. Since no gas is used, it is possible to prevent 02 from being discharged into the atmosphere, thereby preventing air pollution.

Furthermore, since heating and cooling are performed while flowing the liquid metal as a heat medium, the temperature of each part can be easily controlled by controlling the flow rate of the liquid metal.

Therefore, according to the present invention, a product of good quality can be obtained at low cost and through a simple manufacturing process.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of a continuous annealing apparatus according to the present invention, and FIGS. 2 and 3 are diagrams of a heating tank and primary and secondary cooler tanks in the embodiment shown in FIG. FIG. 4 is a graph showing an example of a temperature change pattern during annealing of a general steel plate, and FIG. 5 is a schematic diagram showing the entire conventional example. 20... Continuous annealing device, 21... Furnace body, 22...
Steel plate, 25... Inlet seal roll, 2゛6... Outlet seal roll, 28... Conveying device, 29... Inlet inactive area, 30... Heating area, 31... Primary Isothermal (soaking) area, 33.35... Primary and secondary cooling area, 4o... Liquid metal (liquid metal sodium), 41
a... Heating tank (liquid metal container), 41b... Primary cooling tank (liquid metal container), 41c... Secondary cooling tank (
Liquid metal container), 46... General circulation piping (piping), 47
a~47C...overflow tank, 51a~51
c... Circulation piping (piping), 53a... Heater, 53
b, 53C...Cooler, 55...Surge tank. Applicant's agent Hisahata 7/c Sheep drawing

Claims (1)

[Claims] A conveying device is installed in a closed furnace body having an entrance and exit for the metal to be annealed, which continuously conveys the metal to be annealed in a meandering manner from the inlet side to the outlet side, and the furnace body is thermally isolated from each other. In the continuous annealing apparatus, the metal plate to be annealed is divided into a heating area, a soaking area, and a cooling area, and the metal plate to be annealed passing through the furnace body is continuously annealed. A liquid metal container is installed in which the metal is heated and cooled by immersing it in the liquid metal, respectively;
These liquid metal containers are connected in series by piping, and overflow tanks are interposed in the middle of the piping to accommodate the overflowing liquid metal in each liquid metal container, and downstream of each overflow tank. A heat exchanger and a pump were respectively installed in the pipe to form a closed loop in which the liquid metal was forcibly circulated from the liquid metal container in the cooling area to the liquid metal container in the heating area through the piping. A continuous annealing device characterized by: