JP2021173419A - Pusher device used for continuous type heating furnace, and continuous type heating furnace provided therewith - Google Patents

Abstract

To provide a pusher device used for a continuous type heating furnace and a continuous type heating furnace provided therewith, in which a desired temperature curve is obtained regarding the temperature curve of a workpiece to be heat-treated in accordance with the specifications or the like of a heating furnace and the workpiece.SOLUTION: A pusher device used for a continuous type heating furnace having a plurality of heating zones comprises a pusher pushing a tray mounted with a workpiece, a driving mechanism driving the pusher and a control unit controlling the driving mechanism. The control unit controls the driving mechanism so that the forward time of the pusher is made longer than the backward time thereof.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a pusher device used in a continuous heating furnace and a continuous heating furnace including the pusher device.

As the pusher type continuous heating furnace, for example, there are those disclosed in Patent Document 1 and Patent Document 2. The pusher method has a simpler structure and is cheaper than the roller drive method.

Jitsufuku No. 5-12276 Gazette Jikkenhei No. 2-4195

However, when the work is heat-treated in the continuous heating furnace, the temperature curve for changing the temperature of the work with time (increasing or lowering) varies depending on the specifications of the heating furnace and the work. In the pusher type continuous heating furnace as disclosed in Patent Documents 1 and 2, it can be said that there is room for improvement in obtaining a desired temperature curve according to the specifications of the heating furnace and the work.

Usually, especially in the case of the first work, trial and error are required to determine the temperature curve, so the temperature rise curve is determined by repeating the test in a small batch type heating furnace. In the batch type, since the temperature of the work is raised and lowered at the same place, the temperature change is gradual. However, when trying to reflect this in the production line, in a continuous pusher type heating furnace, the pusher pushes between heating zones with different temperatures to move them all at once, resulting in a rapid temperature change and the temperature obtained in the test results. There is a problem that the curve cannot be reflected exactly.

Further, when trying to make the forward and backward speeds of the pusher different, the rate of change of the speed is up to about 10 times in the practical range in the frequency conversion by the inverter. Further, in a chain-driven transmission such as that used for a bicycle, if the rate of change in speed is increased by, for example, 20 times or more, the size of the sprocket will be too different, and the structure will be complicated. As described above, it has been difficult to realize a speed change rate of 20 times or more with an inverter or a sprocket speed reducer.

The present disclosure is to solve the above problems, and an object of the present invention is to make it possible to obtain a desired temperature curve for a work to be heat-treated in a pusher device and a continuous heating furnace provided with the pusher device.

The pusher device of one aspect of the present disclosure is a pusher device used in a continuous heating furnace having a plurality of heating zones, and is a pusher that pushes a tray on which a work is placed, a drive mechanism that drives the pusher, and the drive. A control unit for controlling the mechanism is provided, and the control unit controls the drive mechanism so that the forward movement time of the pusher is longer than the return time.

According to the above configuration, by making the forward movement time of the pusher longer than the return time, it is possible to slow down the rate at which the temperature of the work changes when the work is pushed and moved by the pusher. Thereby, when the design is changed from the batch type heating furnace to the continuous type heating furnace, a desired temperature curve can be obtained according to the specifications of the continuous type heating furnace and the work with respect to the temperature curve of the work.

In the pusher device, the forward time of the pusher may be set to 20 times or more of the return time. According to the above configuration, the rate of temperature change of the work can be made smaller.

In the pusher device, the drive mechanism includes a first motor that moves the pusher forward, a second motor that restores the pusher, the first motor, the second motor, and the pusher. A clutch mechanism for switching the connection may be provided. According to the above configuration, it is possible to make the difference between the forward movement time and the reverse movement time larger than in the case of controlling the inverter with one motor.

In the pusher device, the first motor and the second motor are geared motors, respectively, and the reduction ratio of the gears of the second motor is larger than the reduction ratio of the gears of the first motor. You may. According to the above configuration, by making the reduction ratios of the gears of the geared motors different, it is possible to generate a speed change of forward and backward movements while using the motor parts of the two geared motors having the same specifications. It is possible to standardize parts and reduce costs.

The continuous heating furnace of one aspect of the present disclosure includes the pusher device and a housing forming the plurality of heating zones. According to the above configuration, the same effect as that of the pusher device can be obtained.

In one aspect of the present disclosure, in the continuous heating furnace, the first temperature before the temperature rise and the second temperature after the temperature rise when the work is heated in the batch type heating furnace are set to the adjacent first temperature. It is adopted as the temperature of the heating zone and the temperature of the second heating zone, respectively, and the time required for raising the temperature of the work from the first temperature to the second temperature is adopted as the forward movement time of the pusher. According to the above method, the temperature curve obtained by testing the work to be heat-treated in a batch type heating furnace can be strictly reflected in the production apparatus.

According to the present disclosure, it is possible to obtain a desired temperature curve for a work to be heat-treated in a pusher device and a continuous heating furnace including the pusher device.

Cross-sectional view of the upstream side (near the inlet opening) of the continuous heating furnace in the embodiment Cross-sectional view of the downstream side (heating zone) of the continuous heating furnace in the embodiment (A) Schematic side view of the drive mechanism in the embodiment, (B) AA arrow view Schematic cross-sectional view for explaining a method of heat-treating a work in a continuous heating furnace according to an embodiment. Schematic cross-sectional view for explaining a method of heat-treating a work in a continuous heating furnace according to an embodiment. Schematic cross-sectional view for explaining a method of heat-treating a work in a continuous heating furnace according to an embodiment. A graph for explaining the content of control by the control unit regarding the movement pattern of the pusher in the embodiment. A graph showing an example of a temperature curve when a work is heat-treated in the continuous heating furnace of the embodiment. Graph showing an example of the temperature curve of the work heat-treated in the batch type heating furnace Graph showing an example of the temperature curve of the work heat-treated in the conventional continuous heating furnace

Hereinafter, a pusher device and a preferred embodiment of the continuous heating furnace used in the continuous heating furnace according to the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the specific configuration of the following embodiments, and the present disclosure includes configurations based on the same technical idea.

(Embodiment)
1A and 1B are diagrams showing a schematic configuration of the continuous heating furnace 2 in the embodiment. FIG. 1A is a cross-sectional view of the upstream side of the continuous heating furnace 2, and FIG. 1B is a cross-sectional view of the downstream side of the continuous heating furnace 2.

The continuous heating furnace 2 is an apparatus having a plurality of heating zones 4 and performing heat treatment while continuously transporting the work S in the transport direction A in the plurality of heating zones 4. The work S is, for example, a mechanical part (gear or the like) loaded in a metal basket. As shown in FIGS. 1A and 1B, the continuous heating furnace 2 includes a housing 6, a plurality of trays 8, and a pusher device 10.

The housing 6 is a member that forms a plurality of heating zones 4. The housing 6 has a partition wall 12 that partitions the plurality of heating zones 4 from each other. The plurality of heating zones 4 are partially partitioned from each other by the partition wall 12, and are provided at positions adjacent to each other via the partition wall 12.

The tray 8 is a member on which the work S is placed. One work S is placed on one tray 8, and a plurality of trays 8 are arranged in a row in a state of being in front-rear contact with each other. The tray 8 is transported in the transport direction A in a state of being mounted on a rail or a roller (not shown) installed inside the housing 6.

As shown in FIG. 1A, the tray 8A located on the most upstream side of the plurality of trays 8 is arranged at a position adjacent to the pusher device 10.

The pusher device 10 is a member for pushing the tray 8A toward the transport direction A. When the tray 8A is pushed, a plurality of trays 8 arranged in contact with each other move integrally in the transport direction A, for example, by a distance of one tray. After that, the pusher device 10 is pulled back to the original position, and a new tray 8 is carried into the most upstream space where the tray 8A is located. The description and illustration of the mechanism for carrying in the new tray 8 will be omitted.

The pusher device 10 includes a pusher 14, a drive mechanism 16, and a control unit 18.

The pusher 14 is a member for contacting the most upstream tray 8A and pushing it in the transport direction A. The pusher 14 can contact the tray 8A through the opening 13 provided in the housing 6. The configuration having such an opening 13 is an example, and the pusher device 10 may adopt any configuration as long as the tray 8A on the most upstream side can be pushed.

The pusher 14 is configured to be reciprocally movable in the forward movement direction B1 and the reverse movement direction B2. The forward movement direction B1 is in the same direction as the transport direction A, and the return direction B2 is in the opposite direction to the forward movement direction B1. The reciprocating movement of the pusher 14 is driven by a drive mechanism 16 that combines a geared motor, a clutch, and a chain.

The detailed configuration of the drive mechanism 16 will be described with reference to FIGS. 2A and 2B. FIG. 2A is a schematic side view of the drive mechanism 16, and FIG. 2B is a view taken along the line AA of FIG. 2A.

As shown in FIG. 2A, the drive mechanism 16 includes a chain 20 and three sprockets 22, 24, 26.

The chain 20 is a member that rotates so as to move the pusher 14 in the front-rear direction. The chain 20 and the pusher 14 are fixedly connected by the rear end portion 14a of the pusher 14, and the rotational force of the chain 20 is transmitted as a force for moving the pusher 14 in the front-rear direction. When the chain 20 rotates in the forward rotation direction R1, the pusher 14 is moved in the forward rotation direction B1, and when the chain 20 rotates in the reverse rotation direction R2, the pusher 14 is moved in the reverse rotation direction B2.

The chain 20 rotates while being supported by the sprockets 22, 24, 26. The sprockets 22, 24, and 26 are members that rotatably support the chain 20.

The sprockets 22 and 24 are not connected to a power source and rotate freely as the chain 20 rotates. On the other hand, the sprocket 26 is connected to the power source via the central shaft 28, and the rotational force of the sprocket 26 is transmitted as the rotational force of the chain 20.

As shown in FIG. 2B, two geared motors M1 and M2 and a clutch mechanism 30 are provided as a power source for rotating the sprocket 26.

The geared motors M1 and M2 are motors that rotate the sprocket 26 in the directions opposite to each other. The first geared motor M1 functions to rotate the sprocket 26 forward, and the second geared motor M2 functions to rotate the sprocket 26 in the reverse direction. When the first geared motor M1 rotates the sprocket 26 in the forward direction, the chain 20 rotates in the forward rotation direction R1 and the pusher 14 moves in the forward direction B1. When the second geared motor M2 rotates the sprocket 26 in the reverse direction, the chain 20 rotates in the reverse rotation direction R2, and the pusher 14 moves in the return direction B2.

The clutch mechanism 30 is a mechanism for switching the connection between the geared motors M1 and M2 and the chain 20. The clutch mechanism 30 is configured to be able to switch between a "forward rotation" mode in which the first geared motor M1 is connected to the chain 20 and a "reverse rotation" mode in which the second geared motor M2 is connected to the chain 20. Has been done.

As a further function, the clutch mechanism 30 has a function of adjusting the forward movement time and the reverse movement time of the pusher 14. When the same clutch mechanism 30 is used for the geared motor M1 and the geared motor M2, the gear reduction ratio of the first geared motor M1 and the gear reduction ratio of the second geared motor M2 are used. Is significantly different. Specifically, the forward speed at which the first geared motor M1 moves the pusher 14 in the forward direction B1 is higher than the reverse speed at which the second geared motor M2 moves the pusher 14 in the reverse direction B2. The reduction ratios of the gears of the geared motors M1 and M2 are adjusted so as to be significantly slower. More specifically, the gears of the geared motors M1 and M2 are decelerated so that the gear reduction ratio of the second geared motor M2 is larger than the gear reduction ratio of the first geared motor M1. Select a ratio. For example, the reduction ratio of the gears of the geared motors M1 and M2 is selected so that the return speed of the pusher 14 is 20 times or more the forward speed.

In this way, by making the forward speed of the pusher 14 significantly slower than the return speed, the rate at which the temperature of the work S changes when the tray 8 is pushed and moved in the transport direction A by the pusher 14 is reduced. be able to.

The drive mechanism 16 described above is controlled by the control unit 18. The control unit 18 shown in FIG. 1A is a member for controlling the drive mechanism 16, and includes, for example, a microcomputer. The control unit 18 is electrically connected to the drive mechanism 16 via wiring or the like, and controls the reciprocating movement of the pusher 14 by controlling the drive mechanism 16.

An example of a method of heat-treating the work S in the continuous heating furnace 2 having the above-described configuration will be described with reference to FIGS. 3A to 3C and FIGS. 4 and 5.

3A to 3C are schematic cross-sectional views for explaining the method. 3A to 3C are diagrams showing a flow when the work S1 arranged in the first heating zone 4A is moved to the second heating zone 4B and heated. The temperature zone of the first heating zone 4A is, for example, 1000 to 1100 ° C., and the temperature zone of the second heating zone 4B is, for example, 1100 to 1200 ° C. Here, an example will be described in which the work S1 is heated in the process of moving from the first heating zone 4A to the second heating zone 4B, and the temperature of the work S1 rises.

FIG. 4 is a graph for explaining an example of control by the control unit 18 regarding the driving method of the pusher 14. In FIG. 4, the horizontal axis represents time and the vertical axis represents the position of the pusher 14. FIG. 5 is a graph showing an example of a temperature curve when the work S1 is heated in one cycle of movement of the pusher 14 shown in FIG. In FIG. 5, the horizontal axis represents time and the vertical axis represents the temperature of work S1.

First, as shown in FIG. 3A, in a state where the work S1 is stopped in the first heating zone 4A, the drive mechanism 16 is controlled by the control unit 18 described above to move the plurality of trays 8 and the plurality of works S. Move in the transport direction A. Specifically, the first geared motor M1 is connected to the chain 20 by the clutch mechanism 30 shown in FIG. 2B, and the first geared motor M1 is driven to bring the chain 20 into the forward rotation direction R1. Rotate. As a result, the pusher 14 is advanced in the forward direction B1.

As shown in FIG. 4, with respect to the advance of the pusher 14, the pusher 14 advances with a forward speed X1 over a forward time t1.

FIG. 3B shows a state in which the work S1 is in the process of moving from the first heating zone 4A to the second heating zone 4B. As described above, since the forward speed X1 when advancing the pusher 14 is slowed down, the time that the work S1 is in the position between the first heating zone 4A and the second heating zone 4B becomes longer. As a result, the temperature rise rate of the work S1 is slower than that when the forward speed X1 of the pusher 14 is high. At the front end and the rear end of the work S1, the front end is heated at a higher temperature, but the temperature at the front end and the rear end of the work S1 does not change so much due to the heat transfer inside the work S1.

FIG. 3C shows a state in which the work S1 moves from the first heating zone 4A to the second heating zone 4B and stops. When the movement of the work S1 is completed, the drive mechanism 16 moves the pusher 14 in the return direction B2 so as to return the pusher 14 to the original position. Specifically, the clutch mechanism 30 shown in FIG. 2B newly connects the second geared motor M2 to the chain 20, and disconnects the first geared motor M1. By driving the second geared motor M2 in this state, the chain 20 is rotated in the reverse rotation direction R2, and the pusher 14 is retracted in the reverse rotation direction B2. Since the tray 8 does not move even when the pusher 14 is retracted, the state shown in FIG. 3C is maintained.

Regarding the retreat of the pusher 14, as shown in FIG. 4, the pusher 14 retreats with a recovery speed X2 over a forward movement time t2. As described above, since the return speed X2 is set to be significantly faster than the forward speed X1, the return time t2 is significantly shorter than the forward time t1.

When the return of the pusher 14 is completed, a new tray 8 is carried in to the place where the tray 8A on the most upstream side is located. The pusher 14 is not driven and stands by until a new tray 8 is loaded. In the example shown in FIG. 4, the pusher 14 waits for a waiting time t3 after retreating to the original position.

As shown in FIG. 4, the control unit 18 controls the drive mechanism 16 so as to repeat this movement cycle with the total of the forward time t1, the recovery time t2, and the standby time t3 as one cycle. According to such control, the work S is continuously heat-treated in the plurality of heating zones 4 while the plurality of work S are intermittently transported in the transport direction A and the new tray 8 and the work S are appropriately replenished. It becomes possible to drive.

For example, the control unit 18 sets the ratio occupied by the forward movement time t1 to be 50% or more in the time of one cycle shown in FIG. As a result, the rate of temperature rise of the work S is slowed down. Further, the control unit 18 is set so that, for example, the forward movement time t1 is 20 times or more the return movement time t2. As a result, the ratio of the time during which the temperature can be gradually increased in one cycle can be increased, and the rate of temperature increase of the work S can be made more gradual.

By controlling one cycle shown in FIG. 4, the temperature curve of the work S as shown in FIG. 5 can be obtained. As shown in FIG. 5, the temperature of the work S stopped in the first heating zone 4A is maintained at the first temperature T1 (for example, 1050 ° C.) of the first heating zone 4A, and the temperature of the pusher 14 is maintained. As the temperature advances, the temperature gradually rises from the first temperature T1. The temperature of the work S rises to the second temperature T2 (for example, 1150 ° C.) of the second heating zone 4B, and the temperature of the work S stopped in the second heating zone 4B is at the second temperature T2. Be maintained.

As described above, by slowing the moving speed X1 of the tray 8 and the work S when moving from the first heating zone 4A to the second heating zone 4B, the temperature of the work S as shown in FIG. 5 It is possible to realize a temperature curve in which the rate of rise is gentle.

Here, there is a case where the temperature rising pattern tested in the batch type heating furnace is to be adopted in the continuous type heating furnace. Comparing the batch type heating furnace and the continuous type heating furnace, the rate of change in the temperature of the work S is slower in the batch type heating furnace than in the continuous type heating furnace. FIG. 6 shows an example of the temperature curve of the work obtained by operating the batch type heating furnace.

On the other hand, FIG. 7 shows an example of the temperature curve of the work obtained when the moving tray is moved to the second heating zone 4B at once in the continuous heating furnace as in the conventional case. In such a continuous heating furnace, the rate of change in the temperature of the work S is larger than that in the batch heating furnace. In such a case, the temperature curve of the work S obtained by the test result of the batch type heating furnace as shown in FIG. 6 deviates greatly, and when the test result of the batch type heating furnace is adopted in the continuous heating furnace. It is not possible to accurately take over and use the test data of the batch type heating furnace.

On the other hand, in the continuous heating furnace 2 of the embodiment, the forward speed X1 of the pusher 14 is set to be slower than the recovery speed X2, and the forward time t1 is set longer than the recovery time t2. , The temperature curve of the work S in which the rate of change in temperature is gradual is realized. As a result, the continuous heating furnace 2 can realize a temperature curve close to the temperature curve of the work S obtained from the test result of the batch heating furnace as shown in FIG. In this way, a desired temperature curve can be realized according to the specifications required for the heating furnace and the work.

In the present embodiment, the first temperature T1 which is the temperature before the temperature rise of the work S and the second temperature T2 after the temperature rise in the test result of the batch type heating furnace shown in FIG. 6 are shown in FIGS. 3A to 3C, respectively. It is adopted as the temperature of the first heating zone 4A and the temperature of the second heating zone 4B shown in. Further, the time t4 required for raising the temperature of the work S from the first temperature T1 to the second temperature T2 is adopted as the forward movement time t1 of the pusher 14. As a result, the temperature curve of the work S as shown in FIG. 5 can be obtained even in the continuous heating furnace 2, and the temperature curve of the batch heating furnace shown in FIG. 6 can be approached.

As described above, the pusher device 10 of the embodiment is a device used for the continuous heating furnace 2 having a plurality of heating zones 4, and drives the pusher 14 for pushing the tray 8 on which the work S is placed and the pusher 14. A drive mechanism 16 for controlling the drive mechanism 16 and a control unit 18 for controlling the drive mechanism 16 are provided. The control unit 18 controls the drive mechanism 16 so that the forward movement time t1 of the pusher 14 is longer than the reverse movement time t2.

According to such a configuration, by making the forward movement time t1 of the pusher 14 longer than the return time t2, the rate at which the temperature of the work S changes when the work S is pushed and moved by the pusher 14 is made gentle. be able to. As a result, for example, when the test data of the temperature curve of the batch heating furnace is reflected in the continuous heating furnace, the temperature curve close to the temperature curve obtained from the test result of the batch heating furnace is realized in the continuous heating furnace. It is possible to obtain a desired temperature curve according to the specifications of the heating furnace and the work.

Further, in the pusher device 10 of the embodiment, the ratio of the forward time t1 to the pusher 14 in one cycle including the forward time t1, the recovery time t2, and the waiting time t3 until the next tray 8 is pushed. It is set to 50% or more. According to such a setting, the rate of temperature change of the work S can be made smaller.

Further, in the pusher device 10 of the embodiment, the forward movement time t1 of the pusher 14 is set to be 20 times or more the return time t2. According to such a setting, the rate of temperature change of the work S can be made smaller, and a desired temperature curve can be obtained according to the specifications of the heating furnace and the work.

Further, according to the pusher device 10 of the embodiment, the drive mechanism 16 includes a first geared motor M1 for moving the pusher 14 forward, a second geared motor M2 for returning the pusher 14, and a geared motor. A clutch mechanism 30 for switching the connection between the M1 and the geared motor M2 and the pusher 14 is provided. In this way, by providing two geared motors M1 and M2 having different reduction ratios, the difference between the forward speed X1 and the reverse speed X2 is made larger than in the case of inverter control by one motor, that is, It is possible to make the difference between the forward movement time t1 and the reverse movement time t2 larger. Although an example in which the reduction ratios are different has been described, motors having different rotation speeds may be used even if the reduction ratios are the same.

Further, according to the pusher device 10 of the embodiment, the first motor M1 and the second motor M2 are geared motors, respectively, and have a second gear than the gear reduction ratio of the first geared motor M1. The reduction ratio of the gear of the motor M2 is larger. In this way, by making the reduction ratios of the geared motors M1 and M2 different, the forward and reverse speed changes while using the motor parts of the two geared motors M1 and M2 with the same specifications. It is possible to standardize parts and reduce costs.

Further, the continuous heating furnace 2 of the embodiment includes the pusher device 10 described above and a housing 6 forming a plurality of heating zones 4. According to such a configuration, the same effect as that related to the pusher device 10 can be obtained.

Although the invention of the present disclosure has been described above with reference to the above-described embodiment, the invention of the present disclosure is not limited to the above-described embodiment. For example, in the above embodiment, the case where the work S is a mechanical part such as a gear has been described, but the present invention is not limited to such a case, and any material may be used as long as it is an object to be heat-treated.

Further, in the above embodiment, the case where the drive mechanism 16 has the configuration shown in FIGS. 2A and 2B has been described, but the case is not limited to such a case. Any drive mechanism may be used as long as the pusher 14 can be moved in the front-rear direction.

Further, in the above embodiment, specific values of temperature and time have been described, but these numerical values are merely examples and are not interpreted in a limited manner.

Although the present disclosure has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various modifications and modifications are obvious to those skilled in the art. It should be understood that such modifications and modifications are included therein, as long as they do not deviate from the scope of the present disclosure by the appended claims. In addition, changes in the combination and order of elements in each embodiment can be realized without departing from the scope and ideas of the present disclosure.

The present disclosure is applicable to pusher devices and continuous heating furnaces used in continuous heating furnaces.

2 Continuous heating furnace 4 Heating zone 4A 1st heating zone 4B 2nd heating zone 6 Housing 8, 8A Tray 10 Pusher device 12 Partition wall 13 Opening 14 Pusher 14a Rear end 16 Drive mechanism 18 Control unit 20 Chain 22 , 24, 26 Sprocket 28 Central axis 30 Clutch mechanism A Transport direction B1 Forward movement direction B2 Recovery direction M1 First motor (first geared motor)
M2 2nd motor (2nd geared motor)
R1 Forward rotation direction R2 Reverse rotation direction S, S1 Work T1 First temperature T2 Second temperature X1 Forward speed X2 Recovery speed t1 Forward time t2 Recovery time t3 Standby time

Claims (6)

A pusher device used in a continuous heating furnace having multiple heating zones.
A pusher that pushes the tray on which the work is placed, and
The drive mechanism that drives the pusher and
A control unit that controls the drive mechanism is provided.
The control unit is a pusher device that controls the drive mechanism so that the forward movement time of the pusher is longer than the return time. The pusher device according to claim 1, wherein the forward movement time of the pusher is set to 20 times or more the recovery time. The drive mechanism is a clutch mechanism that switches the connection between the first motor that moves the pusher forward, the second motor that drives the pusher back, the first motor, the second motor, and the pusher. The pusher device according to claim 1 or 2, further comprising. The first motor and the second motor are geared motors, respectively, and the reduction ratio of the gears of the second motor is larger than the reduction ratio of the gears of the first motor, according to claim 3. The pusher device described. A continuous heating furnace comprising the pusher device according to any one of claims 1 to 4 and a housing forming the plurality of heating zones. In the continuous heating furnace according to claim 5,
The first temperature before the temperature rise and the second temperature after the temperature rise when the work is heated in the batch type heating furnace are adopted as the temperature of the adjacent first heating zone and the temperature of the second heating zone, respectively. A method characterized in that the time required for raising the temperature of the work from the first temperature to the second temperature is adopted as the forward movement time of the pusher.

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