JPS61213324A - Continuous annealing and bluing device for ferrous laminated product or the like - Google Patents

Abstract

PURPOSE:To improve the efficiency of respective treatments for ferrous laminated layers and to economize on energy by disposing successively, via shielding mechanisms, a deoiling furnace, annealing furnace and bluing furnace to a transfer path for materials to be treated and supplying an inert gas to respective furnaces from the outside. CONSTITUTION:The inert gas is fed from a supply device 22 into the deoiling furnace 2 when the ferrous products such as laminated cores advance into the furnace. The products are at the same time heated by a heater by which the oil-component sticking to the surface thereof is evaporated. The materials to be treated are then transferred into the annealing furnace 3 by passing through a communication cylinder which has the atmosphere shielding mechanism 23a and into which the inert gas is blown. The inert gas is fed into the furnace 3 and the materials to be treated are annealed by the heating with the heater during the transfer, by which an Fe3O4 film is formed thereon. The materials enter thereafter a communicating cylinder having the atmosphere shielding mechanism 23b where the materials are cleaned by a barrier gas, then the materials enter the bluing furnace 4. The dry inert gas contg oxygen at a high concn. is fed through an adding part 46 of a branch pipeline 45 into the furnace 4 where the materials are subjected to the bluing treatment while the materials are slowly cooled. The formation of the oxide film is thus intensified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for continuously annealing and bluing iron-based products, particularly products having gaps or holes between parts or parts, such as laminated cores.

(Conventional technology and its problems) Iron product J! Fi 1 products For example, in the case of a laminated core, a thin electromagnetic steel sheet with a phosphoric acid-based or chromic acid-based insulating film applied to the surface is sheared or punched into a predetermined contour, and the required number of sheets are laminated or wound. Consists of.

In order to obtain the desired properties in such iron-based laminated products, it is necessary to remove the oil that adheres during the processing of the blank, as well as remove the distortion caused during processing and the internal stress during cold rolling of the material. Furthermore, it is necessary to form a Fe 2 O film on the surface for rust prevention.

Therefore, an oil firing process is used to remove oil, an annealing process is used to remove distortion and internal stress, and a blackening process is used to prevent rust. Conventionally, each of the above processes was performed in separate furnaces. Because they were held in separate atmospheres, there were the following problems.

■Annealing and slow cooling are performed in exothermic atmospheres with different metamorphic properties, blackening treatment is performed with steam, and furnace air replacement is performed with nitrogen gas, using a variety of gases, and the amount used is large. Since a lot of thermal energy is required to lower the temperature, the processing cost becomes high.

■As each process was carried out independently in separate furnaces, there was an unnecessary amount of time loss and handling operations due to charging, extracting, and waiting for the materials to be processed into each furnace, and there was also a need for atmosphere replacement at the start and end of the workday. Because necessary things take time,
Overall productivity and work efficiency are poor.

■Since flammable gas is used, there are dangers such as explosions and the working environment is poor.

(Means for Solving the Problems) The present invention was created through repeated research in order to solve the above-mentioned conventional problems, and its purpose is to A device that can efficiently perform deoiling, annealing, and blackening of iron products with large gaps using a relatively compact structure and inexpensive atmospheric gas, ensuring significant energy savings and good safety. Our goal is to provide the following.

Generally, it is possible to use gases with the same composition in the deoiling process and the annealing process, but since the bluing process is an oxidation reaction,
Conventionally, it has been thought that it is necessary to use water vapor in an atmosphere different from the first two, that is, in a normal case.

However, according to the experiments conducted by the present inventors, in the case of workpieces such as laminated cores, air (oxygen) is present in minute gaps between the parts, and if this retained air is utilized effectively, especially It has not been possible to produce a good oxide film even if an inert gas is fed in a dry state without using water vapor.

That is, for example, when dry nitrogen gas is used as an inert gas, in the deoiling process, as well as removing oil, a very thin F80 film is generated on the surface due to retained oxygen.
This serves as a base to prevent high-temperature oxidation in the subsequent annealing process, and the film is strengthened in the annealing process and the subsequent bluing process.

By controlling the oxygen concentration in the atmosphere during the bluing process, it is possible to form the film with a uniform desired thickness.

Based on this knowledge, the present invention has developed an integrated tunnel-shaped furnace and a single atmospheric gas, particularly an inert gas such as nitrogen, to perform the deoiling, annealing, and blackening processes in a continuous manner. This is how it was done.

However, if this continuous process is carried out by passing a conveyor belt through a single tunnel furnace body and dividing the inside of the furnace into a deoiling zone, an annealing zone, and a bluing zone, the oil vapor generated in the deoiling process and Due to the intrusion of the bluing zone atmosphere into the annealing zone, the intrusion of the atmosphere from the entrance of the deoiling zone, etc.
Atmosphere characteristics in the deoiling process and annealing process deteriorate, red rust occurs, and protective coatings such as phosphoric acid-based coatings and chromic acid-based coatings on the surfaces of objects to be treated are likely to peel off. Furthermore, in the bluing process, the oxide film may become uneven or the film may be too thick or too thick.
This leads to property deterioration such as a decrease in space factor and inhibition of domain wall movement.

Therefore, the present invention has been developed to avoid the above-mentioned problems associated with continuous processing.The basic feature of the present invention is to provide independent furnaces in the conveying path for continuously transporting the workpieces such as laminated cores. A deoiling furnace, an annealing furnace, and a bluing furnace of the structure are sequentially arranged via an atmosphere isolation mechanism, and a device outside the furnace supplies inert gas to the deoiling furnace, annealing furnace, and bluing furnace, respectively; A means is provided for adjusting the oxygen concentration of the supplied inert gas in accordance with the oxygen concentration in the furnace.

The deoiling furnace is atmospherically separated from the annealing furnace to prevent oil vapor from entering the annealing furnace, and an atmospheric flow is formed from the outlet to the inlet. Further, the annealing furnace is atmospherically separated from the bluing furnace, thereby preventing inert gas for bluing from entering the annealing furnace.

Inert gas, on the other hand, is delivered to each furnace from a common source;
The bluing furnace and/or annealing furnace is equipped with a means for measuring the amount of oxygen in the furnace, which is connected to an inert gas supply system via a controller, and is sealed in the voids of the object to be treated. It automatically detects fluctuations in the oxygen concentration in the furnace due to the degree of diffusion of the oxygen brought in, and adjusts the amount of oxygen in the supplied inert gas so that bluing is always performed at the optimal oxygen concentration under the specified conditions. ing.

The deoiling furnace, annealing furnace, and bluing furnace may be arranged in series. Alternatively, the annealing furnace and the bluing furnace may be arranged in series, and the deoiling furnace is arranged in parallel or parallel to the two furnaces. They may be arranged so as to intersect, and the outlet side of the deoiling furnace may be connected to the inlet side of the annealing furnace.

In the present invention, the object to be processed, such as a laminated core, is first heated in an inert atmosphere while being transported at a predetermined speed to remove oil and remove thin Fe, O, etc.
A film is formed and subsequently annealed by heating in a high temperature inert atmosphere.

Further, the oxide film is controlled to have a predetermined thickness by contacting with an inert atmosphere in which the amount of oxygen is adjusted while the temperature is being lowered.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 8 show an embodiment of the present invention,
Reference numeral 1 denotes a conveying path for transporting the processed material, and pulleys 10 at the front and rear
, 10, a conveyor belt 11 suspended between them, and a variable speed drive mechanism (not shown).

2 is a deoiling furnace, 3 is an annealing furnace, 4 is a bluing furnace,
Each of these furnaces is constructed independently and arranged in series at predetermined intervals so as to surround the conveyor belt side of the feed path 1.

First, the oil heating furnace 2 has a furnace core tube 5 provided with a guide roller 6 in contact with the conveyor belt 11 at the bottom, and a furnace body 7 made of a refractory material surrounding the furnace core tube 5. Inside of 7, the material to be treated is heated from room temperature to a predetermined deoiling temperature, for example, 300 to 4.
A heater 8 is provided that raises the temperature to near 00 degrees.

The furnace core tube 5 protrudes from the front and rear of the furnace body 7, and is provided at its tip with an exhaust pipe 9,9' for discharging inert gas including oil and brought-in air evaporated by heating.

The annealing furnace 3 is configured as a tunnel-shaped furnace body 14 covered with a gas tight box 13 on the outside, and a heater 15 on the inside for raising and holding the workpiece to a predetermined annealing temperature (for example, around 800° C.). A guide roller 6' in contact with the conveyor belt 11 is disposed on the inner bottom.

On the inlet side of the annealing furnace 3, there is a connecting pipe 1 connected to an exhaust pipe 9.
6 is provided. This communication cylinder 16 consists of an inner cylinder 16a and an outer cylinder 16b, and the inner cylinder 16a extends into the exhaust cylinder.

The bluing furnace 4 includes a furnace core tube 17 with guide rollers 6'' disposed on the inner bottom, and a heater 19 surrounding the core tube 17 for obtaining a predetermined temperature drop curve suitable for bluing from the annealing temperature. It consists of a furnace body !8 and a furnace core tube 17.
A connecting tube 20 connected to the outlet of the annealing furnace 3 is formed at the front, and an outlet tube 21 for slow cooling is formed at the rear.

Reference numeral 22 denotes an inert gas supply device installed outside the feed path 1. Nitrogen gas is generally preferred as the inert gas in terms of cost and other factors. The supply device may be a cylinder or a generator that generates nitrogen gas from the atmosphere. In the present invention, a single inert gas is used as the atmosphere in the deoiling furnace 2, annealing furnace 3. It is characterized in that it is supplied to a bluing furnace 4 for deoiling, annealing and bluing.

In this case, it is important to prevent the atmosphere of each stool from flowing into other furnaces, and for this purpose, an atmosphere blocking mechanism 23a is provided at the boundary position of each stool.

23b and 23c are provided.

First, as the atmosphere isolation mechanism 23a between the deoiling furnace 2 and the annealing furnace 3, as shown in FIG. An annular nozzle 26 surrounding the inner cylinder 16a on the inlet side from the body
is provided, and inert gas is ejected centripetally from the annular nozzle 26 into the passage from the supply bag W122 via the pipe 27 to form a gas barrier.
The IJO 6a has a lift 5 to adjust the passage size to suit the size of the object to be processed and to obtain an orifice effect.
28 are provided. These prevent the atmosphere of the oil heating furnace 2 from flowing into the annealing furnace 3.

Moreover, due to the difference in temperature between the two stools, the flow of atmosphere in the deoiling furnace 2 is directed from the outlet side to the inlet side.

Next, at the atmosphere interrupter end 23b between the annealing furnace 3 and the bluing furnace 4, a resistor 25 and an annular nozzle 26 are provided in the connecting tube 2o in the same manner as described above, and a pipe is connected to the annular nozzle from the supply device 22. By introducing an inert gas through the tube 3o, a gas barrier is formed to prevent the atmosphere of the bluing furnace 4 from entering the annealing furnace 3.

In addition, as an atmosphere isolation mechanism 23C of the brewing furnace 4, several resistors 25, 25 are installed in the outlet pipe 21, and an annular nozzle 26' is provided between the resistors, and a pipe 32 is connected from the supply bag a22. The guided inert gas is ejected perpendicularly to the flow path to form an exit barrier.

In addition to the above-mentioned structure, as the atmosphere blocking mechanism, as shown in FIG.
A lift door 30 going down to the passageway is inserted into this, and oblique gas blowing parts 31a are installed on both sides of the base of the rising part 29.
, 31b, and these oblique gas blowing parts 31a, 31b.
There is a structure in which the elevating door 30 is selectively activated. In this structure, for example, if the elevator door 30 is lowered as shown in FIG. 5 and inert gas is blown in from both oblique gas blowing parts 31a and 31b, the elevator door 30 will act as a barrier and the flow will be separated into left and right sides.
By raising the elevator door 30 and operating one of the oblique gas blowing portions 31a or 31b, a gas flow is produced in a desired direction.

Gas introduction parts 34, 34' are arranged at regular intervals in the annealing furnace 3, and these gas introduction parts 34, 34' are connected to the supply device 22 by a pipe 33.

The bluing furnace 4 is also provided with a gas introduction part 35, and is connected to the supply bag [22] by a pipe 36.

The above configuration can prevent the atmosphere from each stool from getting mixed in, but if the object to be processed has minute voids, such as a laminate, the air enclosed in it can Oxygen (oxygen) diffuses, and the degree of diffusion causes variations in the final oxide film in the bluing process.

Therefore, in one aspect of the present invention, at least the bluing process is always performed in an inert atmosphere with a predetermined oxygen concentration, and during operation, the bluing furnace 4 and/or annealing furnace 3 (including passages such as connecting tubes) ) is measured, and the oxygen concentration in the supplied inert gas is adjusted depending on the oxygen concentration.

Specifically, the piping 32, 36 to the brewing furnace 4
is connected to the gas supply device 22 by a separate branch pipe 45 from the pipe 33° 27 of the annealing furnace 3 and the deoiling furnace 2,
Addition section 4 such as a mass flow controller is installed in branch pipe 45.
6 is interposed, and an oxygen or hydrogen supply source 48 is connected to this addition section 46. On the other hand, the gas sampling devices 37 are inserted into the above-described required locations, and the gas sampling devices 37 are connected to any oxygen concentration measuring device 37' such as an optical type or an electric type, and the oxygen concentration measuring device 37'
is connected to the driving section of the flow rate regulating valve 49 of the addition section 46 via the controller 38.

The controller 38 is configured to receive an oxygen concentration value from the supply gas system to the deoiling furnace and annealing furnace. Note that the measurement signal from the oxygen concentration measuring device 37' may also be guided to the gas supply device 22 as required, and the oxygen concentration of the source gas may be adjusted by a controller provided therein.

For example, a gas supply bag! ! When 22 is a generator that generates nitrogen gas from the atmosphere, a purification method is usually used in which hydrogen is added to remove oxygen from the gas from the generator to dehydrate it. Therefore, if the measurement circuit of the oxygen concentration measuring device 37' is connected to the refining section of the generator, the amount of hydrogen added will be adjusted according to the measured value, and the hydrogen content will be supplied to the deoiling furnace, annealing furnace, and bluing furnace. The reference oxygen concentration of the active gas is arbitrarily controlled.

9 and 10 show another embodiment of the present invention,
In this embodiment, compared to the embodiments shown in FIGS. 1 to 7, the installation length of the furnace can be made shorter, and the range of movement for each work or operation can be made smaller.

In this embodiment, the feeding path is a conveyor belt type feeding path 1a.
The annealing furnace 3 and the bluing furnace 4 are arranged in series in the conveyor belt feeding path 1a, and the bushing feeding path 1b is parallel to the conveyor belt feeding path 1a. A deoiling furnace 2 is provided in the area.

The deoiling furnace 2 is equipped with a furnace core tube 5 in which exhaust pipes 9 and 9' are connected in front and rear, and a furnace body 7 that surrounds this, and the materials to be processed are charged into the exhaust pipe 9 side at a predetermined pitch. A button 40 is provided to
The exhaust pipe 9' on the exit side includes a horizontal pipe 41 and an intermediate bushing 4 which are connected in a crosswise manner to the connecting pipe 16' constituting the inlet of the annealing furnace 3.
2 is provided, and the workpieces that have been deoiled are transferred from the horizontal cylinder 41 to the conveyor belt 11 that passes through the communication cylinder 16 one after another by an intermediate busher 42.

Since the annealing furnace 3 and the bluing furnace 4 are the same as those in the embodiment described above, they are designated by the same reference numerals.

The atmosphere blocking mechanism is substantially the same as in the previous embodiment.

Since the deoiling furnace 2 and the annealing furnace 3 are intersected by the horizontal tube 41, the atmosphere of the deoiling furnace 2 and the annealing furnace 3 can be isolated only by a barrier created by introducing an inert gas. A resistor 25 is installed in the connecting tube 16'' of the annealing furnace 3 to prevent outside air from entering.

Since the other configurations are redundant, only the same reference numerals as in the previous embodiment are shown.

In the map, 50 is an air cooling mechanism provided following the brewing furnace.

(Function) Next, the usage state and function of the present invention will be explained by taking the example shown in FIGS. 1 to 8 as an example.

In the present invention, each step of deoiling, annealing, and bluing is performed in an inert gas atmosphere. Therefore, at the start of work, there is no need for two or more stages of atmosphere replacement work, which is required when conventional exothermic gases are used, and the start-up time and gas used can be significantly reduced. This is most noticeable at the end of the day or during interruptions, when heaters and feed lines are turned off and
This can be done in almost zero time, just by stopping the supply of atmospheric gas.

An appropriate number of objects to be processed, such as laminated cores, are placed on trays and placed on a belt conveyor 11 in front of the deoiling furnace 2, thereby entering the deoiling furnace 2.

Inert gas is fed into the furnace core tube 5 from a supply device 22 and is heated by a heater 8. By setting a predetermined belt movement speed, the workpiece is transported in an inert atmosphere. For example, the temperature is raised to around 300 to 400 degrees, thereby evaporating the oil adhering to the surface of the object.

The inert gas is blown in from the annular nozzle 26 in the connecting tube 16 on the inlet side of the annealing furnace, and since there is a temperature difference between the inlet and outlet of the deoiling furnace, the inert atmosphere in the deoiling furnace 2 has a large amount of air in the direction of the inlet. This results in a fast flow, thereby preventing air from entering from the outside, and since the atmospheric gas is an inert gas, the oil is entrained in the flow in the inlet direction and is led to the exhaust stack 9 and released without being ignited and burned. Since the treated object has oxygen on its surface from which oil has been removed, very thin FeJ
06 film begins to form. Because the atmosphere is not atmospheric,
Appropriate oil removal is performed without peeling off the protective film or causing red rust. .

Next, the workpiece is continuously transferred to the annealing furnace 3 through the communication tube 16. In this annealing furnace 3, an inert gas is introduced through a gas tight box 13, and the workpiece is annealed while being transferred because it is heated by a heater 15 to a predetermined annealing temperature, for example, about 800 degrees.

Annealing needs to be carried out under strictly controlled atmospheric conditions; however, in the present invention, an atmosphere blocking mechanism 23a is provided in the communication tube 16 with the deoiling furnace 2, and a gas barrier formed by the annular nozzle 26 and a resistor 26 The atmosphere on the side of the deoiling furnace is prevented from entering, and an atmosphere interrupter @ 23b is also provided in the communication tube 20 between the rear side and the bluing furnace 4, and the atmosphere on the side of the deoiling furnace is prevented by the annular nozzle 26 etc. Since the annealing furnace 3 is shut off, an inert atmosphere is created that is completely separate and independent from the furnaces before and after the annealing furnace 3. Moreover, the workpiece being processed is cleaned by being sprayed with highly pure inert gas around it. It will then be loaded. Therefore, although it is a continuous furnace, highly accurate annealing is performed, and at this time, as the thin Fe)OJ film is formed on the workpiece as mentioned above, this serves as a base and prevents high-temperature oxidation. F
The EP wave film grows further.

The workpiece that has been annealed in this way is then transferred to the connecting tube 2.
0, where it is again cleaned with barrier gas and then enters the brewing furnace 4. In this bluing furnace 4, the heater 19 is operated to gradually lower the temperature from the inlet side to the outlet side, and the inert gas is supplied to the deoiling furnace and the annealing furnace through the addition section 46 of the branch pipe 45. Dryene active gas with a higher oxygen concentration than the
The object to be treated is brought into contact with the inert gas while being slowly cooled.

Air is sealed in minute voids in the material to be treated, and as it is heated in the deoiling furnace, it expands and gradually diffuses, and is discharged from the exhaust pipes 9 and 9' together with the evaporated oil.
Even when it reaches the brewing furnace, some of it remains in the void. Since the inert gas supplied to the bluing furnace has a high oxygen concentration, the residual air on the surface of the workpiece and the air oozing from the surface create an atmosphere with a high oxygen concentration as a whole, and while it passes through the bluing furnace, the inert gas has a high oxygen concentration. The formation of an oxide film on the object to be treated is strengthened.

However, products such as laminated cores have a variety of structures and dimensions, and therefore the amount of air contained in the voids also varies. Furthermore, the degree of diffusion of retained air also varies depending on processing conditions such as moving speed and heating temperature.

Therefore, the oxygen concentration in the bluing furnace fluctuates, and when bluing is performed in an inert atmosphere with a fixed composition, it becomes difficult to accurately form an FeO film of the desired thickness, resulting in Variations occur, such as sometimes being too thick and sometimes being too thin.

However, in the present invention, the atmosphere is sampled during operation in the bluing furnace 4 and/or the annealing furnace 3,
The oxygen concentration in the furnace is automatically detected by the oxygen concentration measuring device 37', and this detection data is sent to the controller 38. The controller 38 contains F870., which is determined empirically from the processing conditions, the amount of air retained depending on the characteristics of the object to be processed, the oxygen concentration in the inert gas supplied to the deoiling/annealing furnace, etc. The degree of film growth and the corresponding optimum oxygen concentration are set, and this and the measured concentration are compared, and the flow rate regulating valve 49 of the addition section 46 of the branch pipe 45 is operated according to the deviation. When the oxygen concentration is too low for the bluing atmosphere, the opening degree of the flow rate regulating valve 49 is increased to increase the oxygen concentration in the supplied inert gas, and when the oxygen concentration is too high, the oxygen concentration The opening degree of the flow rate regulating valve 49 is reduced to the lower limit where the gas is equivalent to the annealing furnace supply gas.

As a result, even if the amount of oxygen contained in the object to be treated or the amount of diffusion changes, the bluing process is always performed at an oxygen concentration within the appropriate range, and a FeJOJ film of the desired thickness is formed uniformly and accurately. be done.

The workpiece on which Fe, O, and films have been formed is slowly cooled in the bluing furnace 4, then further cooled to a lower temperature by the air cooling mechanism 50, and taken out from the conveyor belt 11.

When the present invention was actually tested using a stator core as an object to be processed, it was found that the gas cost was approximately 87% and the amount of gas used was approximately 4% lower than when a heat-generating type was used as the atmosphere gas.
In addition, the temperature raising work, which conventionally required 18 hours, was reduced to 10 hours, and the temperature lowering work, which conventionally required 8 hours, was reduced to zero hours.

One laminated core has a diameter of 100 mm, a height of 50 mm, a conveyance speed of the conveying path of 30 mL/min, a maximum temperature of an oil heating furnace of 00°C, a maximum temperature of an annealing furnace of 800°C, and a bluing furnace of 6
00 to 400°C, and using a generator as an atmospheric gas supply device, high purity nitrogen gas with a residual oxygen content of 1.8 PPM was supplied to the deoiling furnace, annealing furnace and Oxygen is added to the bluing furnace at the same time in the addition section of the branch pipe, and during operation, the concentration measuring device and controller installed in the annealing furnace and the bluing furnace control the concentration inside the bluing furnace. Oxygen concentration 800P
It was controlled within the range of PM or less.

As a result, there is no red rust and no peeling of the protective film.
A good annealed core with a uniform film thickness of 3 μm was obtained.

(Effects of the Invention) According to the present invention described above, the annealing and bluing treatment of iron-based products with minute voids such as laminated cores,
It is inexpensive, can be carried out efficiently with a small amount of gas, and uses little heat energy, and has excellent effects such as greatly improving workability, productivity, and safety.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the continuous annealing and bluing apparatus for iron-based laminated products, etc. according to the present invention, Fig. 2 is a vertical side view thereof, and Fig. 3 is the deoiling furnace in Fig. 2. FIG. 4 is an enlarged view showing the connection between the annealing furnace and the bluing furnace, FIG. 5 is a sectional view showing another example of the atmosphere isolation mechanism in the present invention, and FIG. 6 7 is a half-cut sectional view of an oil heating furnace, FIG. 7 is a half-cut sectional view of an annealing furnace, FIG. 8 is a half-cut sectional view of a bluing furnace, FIG. 9 is a plan view showing another embodiment of the present invention, and FIG. The figure is also a partially cutaway side view. 1... Conveyance path, 2... Deoiling furnace, 3... Annealing furnace, 4...
...Brewing furnace, 22...Inert gas supply device,
23a23b...Atmosphere blocking mechanism, Utility model registration applicant Yamazaki Electric Industry Co., Ltd. Agent Patent attorney Kuro 1) Hiroshi Yasushi Figure 4, 6 Figure 7
Figure 8

Claims (4)

[Claims] (1) A deoiling furnace, an annealing furnace, and a bluing furnace are sequentially installed via an atmosphere isolation mechanism in a conduit for continuously transporting the workpieces such as laminated cores, and the deoiling furnace and the bluing furnace are installed outside the furnace. A continuous annealing and bluing device for iron-based laminated products, etc., characterized by having a device for supplying inert gas to an annealing furnace and a bluing furnace, respectively. (2) Continuous annealing and bluing equipment for iron-based laminated products, etc., according to claim 1, wherein the conveyance path is a belt conveyor, and a deoiling furnace, an annealing furnace, and a bluing furnace are arranged in series. . (3) The annealing furnace and the bluing furnace are arranged in series on a belt conveyor, and the deoiling furnace has a separate feeding path such as a pusher,
A continuous annealing and bluing apparatus for iron-based laminated products, etc., according to claim 1, which is connected to an annealing furnace at the exit side of the deoiling furnace. (4) The system for supplying inert gas to the deoiling furnace, annealing furnace, and bluing furnace, respectively, includes a means for measuring the oxygen concentration in the bluing furnace and/or the annealing furnace, and a signal from this to supply inert gas. A continuous annealing and bluing apparatus for iron-based laminated products, etc., as claimed in claim 1, which is provided with means for adjusting the amount of oxygen in the gas.