JP2023172682A - Heat treatment facility - Google Patents

Abstract

To provide a heat treatment facility which is capable of cooling a treatment object in a conveyance unit which carries the conveyance of the treatment object between batch type heat treatment chambers and capable of adjusting a cooling speed at this time.SOLUTION: A heat treatment facility 1 comprises a first heat treatment chamber 12 and a second heat treatment chamber 13 of a batch type arranged along a rail 10 and a conveyance unit 20 of conveying a treatment object W. The conveyance unit 20 comprises a cooling chamber 56 of cooling the treatment object W, and the cooling chamber 56 comprises a treatment chamber 82 which is formed so as to be partitioned by a heat insulation material in a furnace shell 76 and has a circulation fan 100 of circulating a cooling gas, a gas cooler 98 provided on a flow passage 79 of the cooling gas and a heater 120. The circulation fan 100 and the gas cooler 98 are provided at the lateral of the treatment chamber 82 and between the furnace shell 76 and the treatment chamber 82, and the heater 120 is provided at the upper part of the treatment chamber 82.SELECTED DRAWING: Figure 4

Description

The present invention relates to heat treatment equipment for heat-treating objects to be treated.

BACKGROUND ART Conventionally, materials for steel parts have been subjected to isothermal annealing for the purpose of improving machinability in subsequent processes. Isothermal annealing involves a heating process to transform the steel into an austenite structure, an intermediate cooling process to cool the steel to the target temperature in a relatively short period of time, and a soaking process to soak the steel at the target temperature. . When carrying out such constant temperature annealing, a continuous atmosphere furnace is used, which is equipped with three chambers: a primary furnace for the heating process, a quenching chamber for the intermediate cooling process, and a secondary furnace for the soaking process. It has been common practice to carry out the treatment while supplying charcoal and a reducing gas into the furnace to prevent oxidation (for example, see Patent Document 1 below).

When annealing is performed using a continuous atmosphere furnace as described above, the following points have been considered as problems.
(1) When the continuous atmosphere furnace is restarted after being shut down, it takes time for the atmosphere to become suitable for processing. (2) Therefore, it is necessary to maintain the temperature and atmosphere inside the furnace in order to maintain the atmosphere inside the furnace even when there is no treatment. (3) Therefore, it is necessary to deploy security personnel even on holidays, and additional energy is required to maintain the condition inside the reactor. (4) Since it is a continuous furnace, it is not possible to set a heat pattern according to the weight of each processed product.

Japanese Patent Application Publication No. 10-176217 Japanese Patent Application Publication No. 2015-17790

As a means to solve the above problem, it is possible to use the heat treatment equipment shown in the above-mentioned Patent Document 2 related to the patent application filed by the present applicant. The heat treatment equipment disclosed in Patent Document 2 is equipped with a plurality of batch-type heat treatment chambers and a transport unit that is equipped with a heat retention chamber and transports the workpieces. It has the function to
However, when the heat-retaining chamber is used to cool the workpiece corresponding to the intermediate cooling process, the workpiece is cooled down faster than necessary, and the desired cooling gradient cannot be obtained. The organization turns into something different than what it had planned.

The present invention is based on the above-mentioned circumstances, and is capable of cooling a processed item within a transfer unit responsible for transporting the processed item between batch-type heat treatment chambers, and at the same time reducing the cooling rate at that time. The purpose is to provide heat treatment equipment that can be adjusted.

The heat treatment equipment of the present invention is defined as follows. That is,
(A) a batch-type first heat treatment chamber and a second heat treatment chamber arranged along a conveyance track;
(B) a cooling chamber that accommodates a workpiece and cools the workpiece with a cooling gas, and a delivery chamber that delivers the workpiece between the first heat treatment chamber or the second heat treatment chamber and the cooling chamber; a transport unit comprising;
A heat treatment facility that cools the heat-treated workpiece received from the first heat treatment chamber to a predetermined temperature in the cooling chamber, and transports and charges the workpiece to the second heat treatment chamber,
The cooling chamber includes a processing chamber partitioned by a heat insulating material in the furnace shell, a circulation fan that circulates the cooling gas, and a gas cooler and a heater provided on the flow path of the cooling gas,
The circulation fan is provided outside the furnace shell or on the side of the processing chamber between the furnace shell and the processing chamber,
The gas cooler is provided outside the furnace shell or between the furnace shell and the processing chamber,
The heater is provided either within the processing chamber, above the processing chamber, or below the processing chamber.

According to the heat treatment equipment of the present invention defined in this way, it is possible to perform intermediate cooling treatment in isothermal annealing in the cooling chamber in the transport unit responsible for transporting the workpiece between batch-type heat treatment chambers. A series of heat treatments for annealing can be efficiently performed. Here, in this heat treatment equipment, when performing intermediate cooling treatment in the cooling chamber, the temperature of the cooling gas is adjusted by a gas cooler and a heater. Thereby, the cooling rate of the product to be processed can be adjusted.

In addition, in this heat treatment equipment, since the heater and the circulation fan are arranged at different positions, it is possible to avoid the problem of the circulation fan being overheated and malfunctioning due to the radiant heat of the heater directly hitting the circulation fan.

In this heat treatment equipment, the gas cooler, the circulation fan, the heater, and the workpiece may be arranged in this order along the flow path of the cooling gas circulated by the circulation fan.
By doing this, the temperature of the cooling gas can be adjusted before it hits the workpiece, and since the gas cooler is located on the primary side of the circulation fan, it is possible to prevent high-temperature gas from hitting the circulation fan. can be avoided.

Further, in this heat treatment equipment, a bypass passage can be further formed to allow the cooling gas to flow around the gas cooler.
By doing this, when cooling the processed item, only a part of the cooling gas that has passed through the processed item and reached a high temperature passes through the gas cooler and is cooled, so the heater located on the downstream side is cooled. The load when heating the gas is reduced, and the power consumption of the heater can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which showed the whole structure of the heat treatment equipment of 1st Embodiment of this invention. It is a sectional view showing the internal structure of a heating chamber and a conveyance unit in the same embodiment. It is a top view of the same heating chamber and conveyance unit. 3 is a sectional view taken along line IV-IV in FIG. 2. FIG. It is an explanatory diagram of the operation of the delivery mechanism in the same embodiment. FIG. 3 is a diagram showing each step of heat treatment in the same embodiment together with a heat pattern and a pressure pattern for a processed product. It is a figure showing the main part of a 2nd embodiment of the present invention.

Next, embodiments of the present invention will be described in detail below.
FIG. 6 shows each step of the heat treatment (constant temperature annealing) in this embodiment together with a heat pattern and a pressure pattern for the workpiece W. As shown in the figure, here, the workpiece W is heat-treated, then cooled to a predetermined temperature, soaked at this temperature, and then cooled. Specifically, the workpiece W is heated to 910°C in the heating step K1, cooled to 650°C at a predetermined cooling rate (for example, 1°C/s) in the subsequent intermediate cooling step K2, and then heated to 650°C. It is soaked (soaking step K3) and then cooled (cooling step K4).

FIG. 1 shows a schematic overall configuration of a heat treatment facility 1 according to the first embodiment. In the figure, reference numeral 10 denotes a rail serving as a conveyance track that extends linearly in the left-right direction in the figure, and along this rail 10 a plurality of batch-type heat treatment chambers (heating chamber 12 and soaking chamber 13), which will be described later, are installed. The openings 44 (see FIG. 2) are arranged in a straight line with the openings 44 (see FIG. 2) facing upward in the figure. Further, a charging table 16 is provided at the left end in FIG. 1, and an extraction table 18 is provided at the right end in the same figure.

20 is a transport unit that travels on the rails 10. The transport unit 20 receives the workpiece W on the loading table 16 , travels on the rail 10 , and loads the workpiece W into one of the plurality of heating chambers 12 .
Alternatively, the workpiece W that has been heat-treated in the heating chambers 12 is received from the heating chambers 12, travels on the rail 10, and is loaded into any one of the plurality of soaking chambers 13. .
Further, the transport unit 20 receives the workpiece W subjected to soaking treatment in the soaking chamber 13 , travels on the rail 10 , and transports it to the extraction table 18 . In this example, among the heat treatments shown in FIG. 6, intermediate cooling and cooling after soaking are performed within the transport unit 20.

FIG. 2 shows the internal structure of the heating chamber 12 and the transport unit 20.
As shown in the figure, the heating chamber 12 includes a pressure-resistant furnace shell 22 having a cylindrical shape with a bottom, and a heat insulating material 24 disposed inside the shell. The heat insulating material 24 constitutes a cylindrical heat insulating wall 25 with a bottom. The heat insulating wall 25 forms a processing chamber 26 inside.
This heating chamber 12 is provided with a suction port 32 . The suction port 32 is connected to a vacuum pump (not shown), and by suctioning air from the chamber through the suction port, the inside of the chamber (inside the processing chamber 26) is brought into a vacuum state (depressurized state).

The heating chamber 12 is also provided with a supply port 34 for supplying nitrogen gas into its interior. The nitrogen gas supplied from the supply port 34 is once guided to the header 36, and then from the branch pipe 37 following the header 36 and the nozzle 38 provided in the branch pipe 37 to the inside of the heating chamber 12, specifically the inside of the heat insulating wall 25. is introduced into the processing chamber 26. Although one nozzle 38 is provided in the branch pipe 37 here, a plurality of nozzles 38 may be provided.

The heat insulating wall 25 includes a convection heating fan 39 that agitates and causes convection of the nitrogen gas supplied in the processing chamber 26 and promotes the temperature rise of the workpiece W during the temperature rise period, and a fan 39 that rotates the fan 39 for convection heating. A motor 40 is provided. Further, a water cooling panel 41 for protecting the motor 40 from heat is provided on the heat insulating wall 25 near the motor 40.

The heating chamber 12 is provided with a sliding door 42 that opens and closes an opening 44 . The door 42 slides on the inner surface of the flange 48 by a cylinder 46, and in the closed state, the opening 44 is airtightly sealed via a rubber packing. A plate-shaped heat insulating material 55 is provided on the door 42 so as to move together with the door 42, and the opening 52 of the cylindrical heat insulating wall 25 is closed by this heat insulating material 55.
In the heating chamber 12, a water cooling panel 51 is also provided on the inner surface of the door 42 to protect the rubber packing that airtightly seals the opening 44 from heat.

Although the structure of the heating chamber 12 has been described above, the soaking chamber 13 also has basically the same structure. For this reason, in the internal structure of the soaking chamber 13, only the reference numerals are shown for the same parts as the heating chamber 12, and detailed description thereof will be omitted.

In FIG. 2, the transport unit 20 has a traveling cart 90 that runs on the rails 10, and furthermore, on the traveling cart 90, a cooling chamber 56, which will be described later, is installed together with a delivery chamber 54 in a direction orthogonal to the rails 10. It has a connecting cart 92 that moves forward and backward in the middle and left and right directions to connect and disconnect the delivery chamber 54 and the cooling chamber 56 from the heating chamber 12 and the soaking chamber 13.
Reference numeral 94 denotes a cylinder that moves the connecting cart 92 back and forth in a minute stroke in the left-right direction in FIG. be forced to move.
In this embodiment, these connecting carts 92, rollers 96, cylinders 94, etc. constitute forward/backward moving means.

The transport unit 20 has a delivery chamber 54 at the front on the heating chamber 12 and soaking chamber 13 side, and a cooling chamber 56 at the rear on the opposite side for cooling the workpiece W in steps K2 and K4 in FIG. have.

The delivery chamber 54 has a pressure-resistant rectangular cylindrical wall 58, and forms therein a storage chamber 60 for accommodating the workpiece W. This accommodation chamber 60 is provided with a delivery mechanism 62.
The transfer mechanism 62 transfers the workpiece W between the heating chamber 12 etc. and the cooling chamber 56 at the rear, and has a fork portion 62A and horizontal slide members 62B and 62C as shown in FIG. By sliding them in the horizontal direction, the workpiece W is delivered at the fork portion 62A.

This delivery chamber 54 is provided with a suction port 63, and this suction port 63 is connected to a vacuum pump 64 shown in FIG. It is now possible to do so.
An on-off valve 68A made of a solenoid valve is provided on the suction pipe 66, and the suction port 63 and the vacuum pump 64 are communicated with each other and disconnected from each other by opening and closing the on-off valve 68A.

The transfer chamber 54 is also provided with a supply port 70, as shown in FIG. 3, through which nitrogen gas is supplied into the transfer chamber 54.
The delivery chamber 54 has an opening 72 having no door at its front end, that is, the left end in FIG. A flat frame-shaped packing 74 is provided around the opening 72 in the delivery chamber 54 .
The delivery chamber 54 moves forward toward the heating chamber 12 and the soaking chamber 13 so that the frame-shaped packing 74 is brought into airtight contact with the outer surfaces of the heating chamber 12 and the soaking chamber 13. It is docked in the thermal chamber 13.

On the other hand, the latter cooling chamber 56 has a heat insulating material 78 inside a pressure-resistant furnace shell 76 having a cylindrical shape with a bottom, and the heat insulating material 78 constitutes a heat insulating wall 80 . A processing chamber 82 is formed in the inner region surrounded by the heat insulating wall 80, and the workpiece W to be processed is accommodated therein. A pedestal 84 is provided in the processing chamber 82, and the workpiece W in the processing chamber 82 is placed on the pedestal 84 and supported. Furthermore, openings 104 and 106 are provided at the upper and lower parts of the heat insulating wall 80 forming the processing chamber 82, through which nitrogen gas as a cooling gas, which will be described later, flows.

This cooling chamber 56 is provided with a suction port 86 for evacuating its interior as shown in FIG. 4, and this suction port 86 is connected to the vacuum pump 64 as shown in FIG. In contrast, it is connected through a suction pipe 66B. An on-off valve 68B made of an electromagnetic valve is provided on the suction pipe 66B, and the suction port 86 and the vacuum pump 64 are communicated with each other and disconnected from each other by opening and closing operations of the on-off valve 68B.

The cooling chamber 56 is also provided with a supply port 88 in the furnace shell 76 for supplying nitrogen gas into the cooling chamber 56, as shown in FIG. In this example, the workpiece W accommodated in the processing chamber 82 is cooled using nitrogen gas supplied into the furnace shell 76 as a cooling gas.

In FIG. 4, 100 is a circulation fan that circulates nitrogen gas within the cooling chamber 56, and 102 is a motor that rotates the circulation fan 100. The circulation fan 100 is provided on the left side of the processing chamber 82 in the figure, in an area between the furnace shell 76 and the processing chamber 82 . Further, a partition wall 77 is provided on the right side of the processing chamber 82 in the figure to close off a region between the furnace shell 76 and the processing chamber 82 (region on the right side in the figure).
In this example, the circulation fan 100 passes through an outgoing path 79a that passes through the processing chamber 82 from above to below, as shown by the arrow in FIG. 4, and passes upward between the furnace shell 76 and the processing chamber 82. A circulating flow 79 of nitrogen gas is generated including a return path 79b.

98 is a gas cooler that lowers the temperature of nitrogen gas by heat exchange. Like the circulation fan 100, the gas cooler 98 is provided on the left side of the processing chamber 82 in the figure, between the furnace shell 76 and the processing chamber 82, and is used to collect nitrogen that has passed through the processed product W and has reached a high temperature. Temporarily lower the gas temperature.

Reference numeral 120 denotes a heater for heating nitrogen gas, and in this example, it is disposed directly above the processing chamber 82 and at a position facing the opening 104 at the top.
A temperature sensor 121 detects the temperature of nitrogen gas flowing in the cooling chamber 56, and is installed at a position between the heater 120 and the workpiece W in the gas flow path 79 to detect the temperature of the nitrogen gas flowing in the cooling chamber 56. Detects gas temperature. In this example, a control unit (not shown) connected to the temperature sensor 121 controls the output of the heater 120 so that the temperature of the nitrogen gas detected by the temperature sensor 121 matches a preset target gas temperature. controlled. Note that the temperature sensor 121 can also be installed at a position between the workpiece W and the gas cooler 98 in the gas flow path 79 or on the secondary side of the gas cooler 98.

These gas cooler 98, circulation fan 100, heater 120, temperature sensor 121, and control section constitute a gas cooling device for the workpiece W.
In this gas cooling device, as the circulation fan 100 rotates, nitrogen gas flows downward through the opening 104 at the top of the heat insulating wall 80 and hits the high-temperature workpiece W to cool it, as shown in FIG. At this time, the nitrogen gas, which has become high in temperature due to heat exchange with the workpiece W, flows out from the opening 106 at the bottom of the heat insulating wall 80, and then flows upward through the flow path (return path 79b) between the furnace shell 76 and the processing chamber 82. The gas flows through the gas cooler 98, where the temperature is once lowered. Thereafter, the nitrogen gas is heated by the heater 120 and adjusted to a predetermined temperature. The temperature-adjusted nitrogen gas hits the workpiece W again to cool it. That is, in this example, it is possible not only to simply cool the workpiece W accommodated in the processing chamber 82, but also to cool the workpiece W at a desired cooling gradient by controlling the temperature of the nitrogen gas.

Further, in the transport unit 20, as shown in FIG. 2, an opening 122 is provided between the cooling chamber 56 and the delivery chamber 54, specifically at the end of the cooling chamber 56 on the delivery chamber 54 side. This opening 122 is opened and closed by a door 128 that slides on the inner surface of the flange 126 by a cylinder 124.

Similar to the heating chamber 12, the door 128 of the cooling chamber 56 is also provided with a movable plate-shaped heat insulating material 130 that opens and closes the opening 129 of the heat insulating wall 80. A water-cooled panel 132 is provided on the door 128 to protect the rubber gasket that airtightly seals the portion 122 from heat.

Next, a series of heat treatments in this embodiment will be specifically explained.
First, the transport unit 20 receives the workpiece W on the loading table 16 (see FIG. 1) by the delivery mechanism 62 in the delivery chamber 54, and stores it in the delivery chamber 54. Thereafter, the transport unit 20 moves to the position of one of the heating chambers 12 and transports the workpiece W to be processed.

Thereafter, the conveyance unit 20 moves the delivery chamber 54 forward by a small distance toward the heating chamber 12 together with the cooling chamber 56 at the rear by the cylinder 94, so that the frame-shaped packing 74 at the tip of the delivery chamber 54 is brought into close contact with the outer surface of the heating chamber 12. The device is docked with respect to the heating chamber 12 in such a state that the

Then, with the door 128 between the cooling chamber 56 and the cooling chamber 56 closed, the inside of the delivery chamber 54 is vacuum-suctioned through the suction port 63 by the vacuum pump 64, and the inside of the delivery chamber 54 is reduced to the same vacuum pressure as the heating chamber 12. Ru.

When the pressure inside the delivery chamber 54 becomes a vacuum pressure comparable to the pressure inside the heating chamber 12, the door 42 of the heating chamber 12 is opened, and the workpiece W in the delivery chamber 54 is transferred to the heating chamber by the delivery mechanism 62. 12 into the processing chamber 26 and set on the pedestal 30.

When the workpiece W is loaded into the heating chamber 12, heating of the workpiece W is started, and as shown in heating step K1 in FIG. 6, the workpiece W is heated to the target heating temperature of 910°C. The temperature is raised.

At this time, in order to promote the temperature rise, nitrogen gas is supplied into the heating chamber 12 from the supply port 34, and the convection heating fan 39 is rotated, so that the convection heating fan 39 performs convective heating and the heater 28 emits radiant heat. As a result, the temperature of the workpiece W is quickly raised to the target heating temperature of 910°C. When the temperature of the workpiece W has risen to 910° C., the nitrogen gas inside the heating chamber 12 is evacuated through the suction port 32, and the inside of the heating chamber 12 is reduced to a set vacuum pressure (for example, 10 Pa). Note that the inside of the heating chamber only needs to be at atmospheric pressure or lower, and can be set to about 70 kPa, for example.

When the heat treatment on the workpiece W is finished, the transport unit 20, which was once separated from the heating chamber 12, is moved forward again toward the heating chamber 12, and the delivery chamber 54 is docked with the heating chamber 12. Then, the inside of the delivery chamber 54 and the inside of the cooling chamber 56 are evacuated by the vacuum pump 64 to bring them to a vacuum pressure (same pressure as the chamber 12).

Thereafter, the door 42 of the heating chamber 12 is opened, and the workpiece W after the heat treatment in the heating chamber 12 is moved into the delivery chamber 54, and subsequently, it is moved from the delivery chamber 54 to the cooling chamber 56. Then, the workpiece W is accommodated in the cooling chamber 56.

After the workpiece W is accommodated in the cooling chamber 56, the door 128 is closed, and then, as shown in the intermediate cooling step K2 in FIG. 6, the workpiece W is cooled to a target temperature (for example, 650° C.). At this time, nitrogen gas is supplied into the cooling chamber 56 from the supply port 88, and the circulation fan 100 is rotated to circulate the nitrogen gas. At this time, the temperature of the nitrogen gas that hits the workpiece W is also adjusted by the gas cooler 98 and the heater 120, so the workpiece W can be cooled at a desired cooling gradient.
Note that nitrogen gas may be supplied in a fixed amount or in a variable manner. In the case of variable supply, for example, it is possible to control the nitrogen gas flow rate so that the furnace pressure matches a preset target furnace pressure. Further, the pressure inside the furnace can be controlled to be a constant pressure, and may be atmospheric pressure or a predetermined pressurized state higher than atmospheric pressure. By circulating nitrogen gas under a predetermined pressurized state, it is also possible to improve the heat transfer efficiency of convection and reduce temperature variations between materials during cooling.

When the workpiece W has been cooled to the target temperature, the nitrogen gas inside the cooling chamber 56 is evacuated through the suction port 86, and the pressure inside the cooling chamber 56 is reduced. The workpiece W to be processed is maintained at a target temperature.
Note that the target temperature in the intermediate cooling step is the temperature that takes the shortest time to obtain the desired structure, and is generally 550 to 680°C. More specifically, it can be determined using a constant temperature transformation curve. For example, if a fine ferrite-pearlite structure is desired, the temperature can be set at 550°C for SAE1541 and 680°C for SCM420. Further, the cooling rate to the target temperature can be determined by taking into account the nose of the isothermal transformation curve, and can be, for example, 0.1 to 10°C/s, and 0.3 to 10°C/s. It is preferable to set it as 3 degreeC/s.

When the transfer unit 20 moves away from the heating chamber 12 and the pressure in the transfer chamber 54 and the pressure in the soaking chamber 13 become the same vacuum pressure, the workpiece W kept at the target temperature is removed. is then charged into the soaking chamber 13 through the transfer chamber 54.

The workpiece W loaded into the soaking chamber 13 is then equalized inside the soaking chamber 13 while being maintained at 650° C., which is the isothermal holding temperature in constant temperature annealing, as shown in the soaking step K3 in FIG. Heat treated. Specifically, with the door 42 (see FIG. 2) in the soaking chamber 13 closed, the workpiece W is kept at 650° C. by heating by the heater 28 .

When the soaking process is completed, the delivery chamber 54 of the transport unit 20 is docked to the soaking chamber 13. The soaked workpiece W is then taken out from the soaking chamber 13 and moved into the delivery chamber 54, and subsequently moved from the delivery chamber 54 to the cooling chamber 56 to cool the workpiece W. It is housed in a chamber 56.

The workpiece W accommodated in the cooling chamber 56 is then cooled as shown in FIG. 6 (see cooling step K4). Specifically, nitrogen gas is supplied into the cooling chamber 56 from the supply port 88, the circulation fan 100 is rotated, and the workpiece W is cooled by being exposed to nitrogen gas as a cooling gas.

When cooling is completed, the door 128 of the cooling chamber 56 is opened, and the workpiece W is discharged through the opening 72 to the extraction table 18 at the right end in FIG. The workpiece W discharged onto the extraction table 18 is then taken to a downstream process.

According to the heat treatment equipment 1 of the present embodiment configured as described above, the intermediate cooling process can be performed in the cooling chamber 56 in the transport unit 20 which is responsible for transporting the workpiece W between batch-type heat treatment chambers. This makes it possible to efficiently perform a series of heat treatments for constant temperature annealing.
Each batch-type heat treatment chamber is equipped with a degassing function using a vacuum pump, and the atmosphere inside the furnace can be changed to a state suitable for processing in a short period of time. It is not necessary to maintain the condition of the atmosphere inside the furnace, and it is possible to reduce wasteful energy usage just for maintaining the condition of the atmosphere inside the furnace.
Further, in the heat treatment equipment 1 of this embodiment, the temperature of nitrogen gas as a cooling gas is adjusted by the gas cooler 98 and the heater 120 during intermediate cooling in the cooling chamber 56. Thereby, the cooling rate of the workpiece W can be adjusted.

Furthermore, in the heat treatment equipment 1 of the present embodiment, the heater 120 is arranged above the processing chamber 82 and the circulation fan 100 is arranged on the side of the processing chamber 82, so that the radiant heat of the heater 120 directly hits the circulation fan 100. This makes it possible to avoid the problem of the circulation fan 100 being overheated and breaking down.

Furthermore, in the heat treatment equipment 1 of the present embodiment, the gas cooler 98, the circulation fan 100, the heater 120, and the workpiece W are arranged in that order along the flow path 79 of nitrogen gas circulated by the circulation fan 100. The temperature of the nitrogen gas can be adjusted appropriately before it hits the workpiece W, and since the gas cooler 98 is located on the primary side of the circulation fan 100, high temperature nitrogen gas can be prevented from hitting the circulation fan 100. I can do it.

FIG. 7 is a diagram showing essential parts of the second embodiment of the present invention.
In the heat treatment equipment 1B of the second embodiment, a partition wall 135 extending in the vertical direction is provided in the region between the furnace shell 76 and the processing chamber 82 to divide the gas flow path into two, and a gas cooler 98 is installed only in one flow path 136. is provided. The other flow path 137 is a bypass flow path that bypasses the gas cooler 98 and allows nitrogen gas to flow therethrough. In this example, a damper 139 for flow rate adjustment is provided in the bypass flow path 137, and a temperature sensor 121B is provided between the gas cooler 98 and the heater 120 in the gas flow path 79. The damper 139 is configured to be able to adjust its opening degree based on, for example, the gas temperature on the secondary side of the gas cooler 98 detected by the temperature sensor 121B. Note that the temperature sensor 121B can also be provided between the workpiece W in the gas flow path 79 and the gas cooler 98, and in this case, the opening degree of the damper 139 can be adjusted based on the gas temperature on the primary side of the gas cooler 79. It is possible to configure it so that it can be adjusted.

After passing through the workpiece W, the nitrogen gas is divided into two flow paths 136 and 137, and then merges on the secondary side of the gas cooler 98, and the merged nitrogen gas is further directed toward the heater 120 downstream. Sent. Note that among the constituent parts of the heat treatment equipment 1B, the same components as those of the heat treatment equipment 1 according to the first embodiment are indicated using the same reference numerals, and the explanation thereof will be omitted.

According to the heat treatment equipment 1B configured in this way, when cooling the workpiece W, only a part of the nitrogen gas that has passed through the workpiece W and has become high temperature passes through the gas cooler 98 and is cooled. , the load on the heater 120 located on the downstream side when heating nitrogen gas is reduced, and the power consumption of the heater 120 can be suppressed.

Although the embodiments of the present invention have been described in detail above, these are merely examples. For example, as shown below, the present invention can be configured with various changes without departing from the spirit thereof.
(1) In the above embodiment, as shown in FIG. 4, the return path 79b in the cooling gas flow path 79 is provided on the side of the processing chamber 82 and between the furnace shell 76 and the processing chamber 82. In the invention, it is also possible to provide the return path 79b outside the furnace shell 76 and provide the gas cooler 98 and circulation fan 100 there.
(2) In the above embodiment, the gas cooler 98 and the circulation fan 100 are provided only on the left side of the processing chamber 82 in the figure, as shown in FIG. It is also possible to install one set for each (two sets in total).
(3) In the above embodiment, the heater 120 is provided outside (above) the processing chamber 82 as shown in FIG. It is also possible to provide a heater 120.
(4) In the above embodiment, as shown in FIG. 4, the flow 79a of the cooling gas when cooling the workpiece W is a down flow that is introduced from above the processing chamber 82 and exits downward. However, in the present invention, it is also possible to arrange the heater 120 below the processing chamber 82 so that the flow of the cooling gas is an upflow that is introduced from below the processing chamber 82 and exits upward. In this case as well, it is preferable that the gas cooler, circulation fan, heater, and workpiece be arranged in that order along the nitrogen gas flow path.
(5) In the above embodiment, nitrogen gas is used as the atmospheric gas, but depending on the case, it is also possible to use a low oxidizing gas and/or a reducing gas other than nitrogen gas.
(6) In the above embodiment, both the intermediate cooling and the post-soaking cooling shown in FIG. It is also possible to configure the heat treatment equipment so that the heat treatment chamber for cooling is separately arranged and the cooling process is performed after the soaking treatment.

1,1B Heat treatment equipment 10 Rail 12 Heating chamber (first heat treatment chamber)
13 Soaking chamber (second heat treatment chamber)
20 Transfer unit 54 Delivery chamber 56 Cooling chamber 76 Furnace shell 79 Gas flow path 82 Processing chamber 98 Gas cooler 100 Circulation fan 120 Heater 137 Bypass flow path W Workpiece

Claims (3)

(A) a batch-type first heat treatment chamber and a second heat treatment chamber arranged along a conveyance track;
(B) a cooling chamber that accommodates a workpiece and cools the workpiece with a cooling gas, and a delivery chamber that delivers the workpiece between the first heat treatment chamber or the second heat treatment chamber and the cooling chamber; a transport unit comprising;
A heat treatment facility that cools the heat-treated workpiece received from the first heat treatment chamber to a predetermined temperature in the cooling chamber, and transports and charges the workpiece to the second heat treatment chamber,
The cooling chamber includes a processing chamber partitioned by a heat insulating material in the furnace shell, a circulation fan that circulates the cooling gas, and a gas cooler and a heater provided on the flow path of the cooling gas,
The circulation fan is provided outside the furnace shell or on the side of the processing chamber between the furnace shell and the processing chamber,
The gas cooler is provided outside the furnace shell or between the furnace shell and the processing chamber,
The heater is a heat treatment equipment that is provided in the processing chamber, above the processing chamber, or below the processing chamber. The heat treatment equipment according to claim 1, wherein the gas cooler, the circulation fan, the heater, and the workpiece are arranged in this order along a flow path of the cooling gas circulated by the circulation fan. The heat treatment equipment according to claim 2, further comprising a bypass flow path that allows the cooling gas to flow around the gas cooler.

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