JP2014214969A - Continuous heat treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous heat treatment device which can prevent workpieces from being warped due to the local lowering of a temperature even if cold air intrudes into a heat treatment chamber upon the opening/closing of partitioning doors of the heat treatment chamber, in a continuous annealing furnace which continuously transfers pallets mounted with the workpieces into the heat treatment chamber which is filled with an atmosphere gas, and heat-treats the workpieces, as the heart treatment furnace for heat-treating the workpieces.SOLUTION: A continuous heat treatment device comprises: a purge chamber 3; a heat treatment chamber 2 which is continuously connected to the purge chamber 3, and has a heater; and a transfer device which is arranged at least at either of the purge chamber or the heat treatment chamber, and transfers a plurality of the pallets. Partitioning doors 22 which open and close when the pallets pass are arranged at a carry-in port of the purge chamber, a transfer port 21 from the purge chamber to the heat treatment chamber, and a carry-out port of the heat treatment chamber. Block plates 8 are arranged at pallet ends of the pallets at the sides opposite to the transfer direction to the heat treatment chamber from the purge chamber.

Description

The present invention relates to a continuous heat treatment furnace for heat-treating a plurality of workpieces.

As a heat treatment furnace for heat-treating workpieces made of steel, a heater installed on the side of the heat treatment chamber by continuously transporting a pallet on which the workpiece is placed in a heat treatment chamber filled with an atmosphere gas such as an inert gas There is a continuous annealing furnace that performs heat treatment by the heating means. This continuous annealing furnace is generally provided with a purge chamber that prevents outside air from entering the heat treatment chamber by replacing the outside air with atmospheric gas as a front chamber of the heat treatment chamber. In addition, partition doors are installed at the inlet of the purge chamber and the transfer port from the purge chamber to the heat treatment chamber, and the purge chamber and the heat treatment chamber are sealed by opening and closing the partition door when passing through the pallet.

However, in the conventional continuous heat treatment furnace as described above, when the partition door opens and closes through the pallet, the cool air in the purge chamber not provided with the heating means enters the heat treatment chamber provided with the heating means. Due to the intrusion of the cold air, there has been a problem that the workpiece on the pallet that has been heat-treated in the heat treatment chamber is locally lowered in temperature and distorted.

On the other hand, Patent Document 1 discloses a technique for opening the partition door between the purge chamber and the heat treatment chamber while keeping the pressure in the purge chamber and the heat treatment chamber at the same pressure, and transferring the pallet from the purge chamber to the heat treatment chamber. Disclosure. According to this, it is said that fluctuations in the concentration or pressure of the atmospheric gas in the heating chamber can be suppressed as much as possible, and the atmospheric gas can be prevented from being disturbed.

JP2002-318081

However, if the pressure in the purge chamber and the heat treatment chamber are set to the same pressure, it is necessary to provide an atmospheric gas supply means in the purge chamber, and the heat treatment furnace has a complicated configuration and must be controlled in a complicated manner. As a result, there is a concern that the cost will increase.

In view of the above-described conventional problems, the present invention can easily prevent the workpiece heated in the heat treatment from locally falling in temperature due to cold air entering from the purge chamber. An object of the present invention is to provide a continuous heat treatment furnace capable of preventing the distortion of steel.

In order to solve the conventional problems as described above, the invention described in claim 1 has the following configuration.
A purge chamber; a heat treatment chamber connected to the purge chamber in the conveyance direction; and provided with a heating device; and a conveyance device installed in at least one of the purge chamber or the heat treatment chamber and conveying a plurality of pallets. In the continuous heat treatment furnace in which a partition door that opens and closes when the pallet passes is provided at a carry-in port of the purge chamber, a transfer port from the purge chamber to the heat treatment chamber, and a carry-out port of the heat treatment chamber, the pallet Is provided with a shielding plate, and the shielding plate is installed at a pallet end opposite to a transfer direction from the purge chamber to the heat treatment chamber.

According to the first aspect of the present invention, the temperature of the cold air is reduced by the shielding plate heated together with the work by the heater in the heat treatment chamber before the cold air entering the heat treatment chamber from the purge chamber when the partition door is opened and closed contacts the work. Can be raised. Therefore, it is possible to prevent the problem that the temperature of the work heated by the heater in the heat treatment chamber is locally lowered by the cold air and the work is distorted.

The invention described in claim 2 has the following configuration.
The shielding plate is made of a low expansion metal.

According to the second aspect of the present invention, if the shielding plate is made of a low expansion metal, it is heated by a heater in the heat treatment chamber or cooled by contact with cold air that enters the heat treatment chamber from the purge chamber when the partition door is opened and closed. Even if it is repeated, distortion and undulation are less likely to occur. As a result, the life of the shielding plate can be extended.

The present invention configured as described above has the following effects. That is, the shielding plate installed on the pallet is heated together with the workpiece by the heater in the heat treatment chamber. The heated shielding plate can raise the temperature of the cool air before the cool air entering the heat treatment chamber from the purge chamber contacts the workpiece when the partition door is opened and closed. By raising the temperature of the cold air, it is possible to prevent the problem that the temperature of the work heated by the heater in the heat treatment chamber is locally lowered and the work is distorted.

It is a top view of the continuous heat treatment furnace of the present invention. It is a longitudinal cross-sectional view (AA cross section of FIG. 1) of the continuous heat processing furnace of this invention. It is a figure which shows the method of conveying the pallet in the purge chamber of the continuous heat processing furnace of this invention into the heat processing chamber. It is a figure which shows the method of conveying the pallet on the stand by the continuous heat processing furnace of this invention in a purge chamber.

Hereinafter, a preferred embodiment showing a continuous heat treatment furnace of the present invention will be described with reference to the drawings. In the following description, only the configuration on the inlet side of the continuous heat treatment furnace will be described in order to simplify the description.

FIG. 1 is a plan view of a continuous heat treatment furnace of the present invention. As shown in FIG. 1, the continuous heat treatment furnace 1 of the present embodiment according to the present invention includes a heat treatment chamber 2 for performing heat treatment of a workpiece W made of steel by a heater 24 installed on a side surface. Examples of the heater include a far infrared heater, a blower heater, and an oil heater.

A purge chamber 3 is connected to the front chamber (left side in FIG. 1) of the heat treatment chamber 2 to prevent the outside air from entering the heat treatment chamber by replacing the outside air with the atmospheric gas. In the front chamber of the purge chamber 3 (downward in FIG. 1), a stand 4 for placing the pallet 5 on which the workpiece W is placed on standby is installed.

  The purge chamber 3 is provided with a carry-in port 31 for carrying the pallet 5 in the heat treatment chamber 2 heated by the heater 24 from the stand 4 into the purge chamber 3. A partition door 32 for partitioning the outside air and the purge chamber is installed at the carry-in entrance 31.

Further, a transfer port 21 for transferring the pallet 5 from the purge chamber 3 to the heat treatment chamber 2 is provided between the purge chamber 3 and the heat treatment chamber 2. A partition door 22 is installed at the transfer port 21 so as not to lower the temperature in the heat treatment chamber 2.

The partition doors 22 and 23 are respectively provided with drive devices (not shown), and their drive means drive the partition doors 22 and 23 up and down.

A tray pusher (not shown) is installed in front of the stand 4 (downward in FIG. 1). The tray pusher in front of the stand 4 is constituted by a rod 6 and a hydraulic device (not shown), and the hydraulic device moves the rod 6 forward and backward. As the rod 6 moves forward, the pallet 5 placed on the standby table 4 is carried into the purge chamber 3 from the standby table 4.

A tray pusher (not shown) is installed in the reverse conveyance direction (leftward in FIG. 1) of the purge chamber 3. The tray pusher in the reverse conveyance direction of the purge chamber 3 is constituted by a rod 7 and a hydraulic device (not shown), and the hydraulic device moves the rod 7 forward and backward. As the rod 7 moves forward, the pallet 5 in the purge chamber 3 is transferred from the purge chamber 3 to the heat treatment chamber 2.

The conveying means is not limited to the tray pusher. A plurality of rollers are arranged at intervals, and each roller rotates in the same direction by an actuator such as a motor to convey the tray, and a belt conveyor has the same effect as the present invention.

FIG. 2 is a longitudinal sectional view (AA sectional view of FIG. 1) of the continuous heat treatment furnace of the present invention. As shown in FIG. 2, the heat treatment chamber 2 is provided with a supply device that supplies atmospheric gas such as enrich gas, RX gas (CO gas), and nitrogen (N 2) gas by a supply device (not shown). The atmospheric gas supplied from the supply device is supplied into the heat treatment chamber 2 from a supply port 23 provided at the upper part of the heat treatment chamber 2.

The atmospheric gas supplied into the heat treatment chamber 2 is stirred into the heat treatment chamber 3 by a blower 26 that is rotatably installed at the top of the heat treatment chamber 3, and as a result, the temperature in the heat treatment chamber 3 becomes constant. In addition, as the air blower 26 installed rotatably, an axial flow fan, a multiblade fan, a recirculation fan, etc. are mentioned.

Further, the atmosphere gas supplied from the supply port 23 is filled in the heat treatment chamber 2. Part of the filled atmosphere flows into the purge chamber 3 through the vent 25 provided in the partition door 22. The atmospheric gas that has flowed into the purge chamber 3 is filled into the purge chamber 3. A part of the filled atmospheric gas is discharged out of the purge chamber from the discharge port 33 provided at the upper portion of the purge chamber 3.

On the pallet 5, a shielding plate 8 for shielding cold air entering from the purge chamber 3 when the partition door 22 is opened and closed is installed perpendicularly to the pallet 5. When the pallet 5 is placed in the heat treatment chamber 2, the shielding plate 8 is located at the end of the pallet 5 on the side opposite to the transfer direction from the purge chamber 3 to the heat treatment chamber 2. That is, in the heat treatment chamber 2, the shielding plate 8 installed on the pallet 5 is installed closer to the partition door 25 than the workpiece W installed on the same pallet 5. Therefore, the cold air that enters the heat treatment chamber 2 when the partition door 22 is opened and closed contacts the shielding plate heated by the heater 24 in the heat treatment chamber 2 before contacting the workpiece W. As a result, the temperature of the cold air can be raised, and the problem that the temperature of the workpiece W heated by the heater 24 in the heat treatment chamber is locally lowered and the workpiece is distorted can be prevented.

The shielding plate 8 has a height and width equal to or greater than those of the workpiece W. Since the shielding plate 8 heated in the heat treatment chamber has a height and width equal to or greater than that of the workpiece W, it actively contacts cold air entering the heat treatment chamber 2 from the purge chamber 3 when the partition door 25 is opened and closed. To do. Since the shielding plate 8 and the cold air positively contact each other, the temperature of the cold air can be easily increased.

The shielding plate 8 is made of a low thermal expansion metal material such as tungsten or molybdenum. If the shielding plate 8 is made of a low expansion metal, even if the heating by the heater 24 in the heat treatment chamber 2 and the contact with the cold air entering the heat treatment chamber 2 when the partition door 22 is opened and closed, distortion and undulation are repeated. Is less likely to occur. As a result, the life of the shielding plate 8 can be extended, and maintenance costs can be reduced.

The heat treatment chamber 2 includes a control device (not shown). The control device includes a heater 24 in the heat treatment chamber, a drive device that drives the partition doors 32 and 22, a tray pusher that conveys the pallet 5, a blower 26 that is rotatably installed in the upper portion of the heat treatment chamber 3, and the heat treatment chamber 2. It is electrically connected to an atmospheric gas supply device. The heat treatment chamber 3 is provided with temperature measuring means (not shown) such as a contact temperature sensor such as a thermocouple for measuring the temperature in the heat treatment chamber 3 or a non-contact temperature sensor. Then, based on the temperature measured by the temperature measuring means, the control device heats the heater 24, opens and closes the partition doors 32 and 22, advances and retracts the tray pusher, blows the blower, and supplies from the atmospheric gas supply device. Control the amount. As a result, the temperature of the heat treatment chamber can be maintained at a predetermined temperature for a predetermined time. The temperature in the heat treatment chamber 2 is set to about 600 to 900 ° C., for example.

Next, in the continuous heat treatment furnace 1 configured as described above, the flow until the pallet 5 placed on the stand 4 is carried into the heat treatment furnace 3 will be described with reference to FIGS. FIG. 3 and FIG. 4 are diagrams showing the method of transporting the continuous heat treatment furnace of the present invention, FIG. 3 is a diagram showing a method of transporting the pallet in the purge chamber into the heat treatment chamber, and FIG. It is a figure which shows the method of conveying in a purge chamber.

First, the drive means installed in the partition door 22 opens the partition door 22 upward, and the pallet 5 placed in the purge chamber 5 is moved forward into the heat treatment chamber 3 by moving the rod 7 of the tray pusher forward. Bring it in. At that time, the pallet 5 transported from the purge chamber 3 into the heat treatment chamber 2 is transported so as to push out the plurality of pallets 5 previously transported into the heat treatment chamber 2 in the transport direction. Thereafter, the rod 7 of the tray pusher is retracted and the partition door 22 is closed.

Next, the partition door 32 is opened upward by the driving means installed in the partition door 32, and then the pallet 5 placed on the standby table 4 is advanced by the rod 6 of the tray pusher, thereby moving the purge chamber. 3 to carry. Thereafter, the rod 6 of the tray pusher is retracted and the partition door 32 is closed. In the pallet 5 conveyed into the heat treatment chamber 2, the shielding plate 8 installed on the pallet 5 is heated together with the workpiece W by the heater 24 installed on the side surface in the heat treatment chamber 2, from 600 ° C. to 900 ° C. The temperature rises.

After a lapse of a certain time from the temperature rise, the partition door 22 is opened in order to transport the pallet 5 waiting in the purge chamber 3 into the heat treatment chamber 2. When the partition door 22 opens, the cold air in the purge chamber 3 enters the heat treatment chamber 2 from the carry-in entrance 21. The cold air that has entered the heat treatment chamber 2 rises in temperature as it approaches the shielding plate 8 heated in the heat treatment chamber 2. By raising the temperature of the cold air, it is possible to prevent the problem that the temperature of the work W heated in the heat treatment chamber 2 is locally lowered and the work W is distorted.

Although an example of a preferred embodiment of the present invention has been described above, the present invention is not limited to the embodiment described here. For example, in the present embodiment, the shielding plate 8 may have a structure having a plurality of holes in the direction of the thickness of the shielding plate. Since the shielding plate 8 has a plurality of holes, the weight of the shielding plate 8 can be reduced, and the driving force of the tray pusher that conveys the pallet 5 on which the shielding plate 8 is installed can be reduced. As a result, the tray pusher can be reduced in size.

Moreover, the shielding board 8 does not need to be comprised by the plate-shaped thing, The structure which combined the rod-shaped thing may be sufficient. If it is the shielding board 8 which combined the rod-shaped steel materials, it will become unnecessary to carry out a hole processing to plate-shaped steel materials separately, and can reduce manufacturing cost.

Further, the shielding plate 8 installed on the illustrated pallet 5 is installed at a part of the end of the pallet 5, but the shielding plate 8 may be installed so as to surround the workpiece W on the pallet 5. . Since the shielding plate 8 is installed so as to surround the workpiece W, the cold air that enters the heat treatment chamber 2 when the partition door 25 is opened and closed contacts the workpiece W even when it enters along the side surface of the heat treatment chamber 2. Before doing so, the temperature of the cold air can be raised. By raising the temperature of the cold air, it is possible to prevent the problem that the temperature of the workpiece W heated by the heater 24 in the heat treatment chamber 2 is locally lowered and the workpiece W is distorted.

Further, the shielding plate 8 is plate-shaped, but it may have a shape extending so as to cover the upper portion of the workpiece W. If the shielding plate 8 has a shape that covers the upper part of the work W, even if cool air that enters the heat treatment chamber 2 enters and exits along the upper part of the heat treatment chamber 2 when the partition door 25 is opened and closed, before the contact with the work W The upper part of the heated shielding plate 8 is contacted. As a result, the temperature of the cold air can be raised, and the problem that the temperature of the work heated by the heater in the heat treatment chamber 2 is locally lowered and the work W is distorted can be prevented.

Further, the number of workpieces W on the pallet 5 is not limited to one, and if a jig capable of placing a plurality of workpieces W on the pallet 5 is provided, the plurality of workpieces W can be conveyed simultaneously. it can.

When conveying a plurality of workpieces W at the same time, the height and width of the shielding plate 8 are increased. That is, the projection surface in the conveyance direction of the shielding plate 8 is shaped so as to cover the plurality of workpieces W. As a result, the cool air that enters the heat treatment chamber 2 when the partition door 25 is opened and closed contacts the shielding plate 8 before it contacts the plurality of workpieces W, and the temperature of the cool air can be increased.

In addition, when conveying a plurality of workpieces W at the same time, even if the shielding plate 8 is installed so as to surround the plurality of workpieces W or has a shape extending so as to cover the top of the workpiece W, The same effect is produced.

The heat treatment chamber 2 of the present invention can be used for various purposes of heat treatment for various forms of workpieces regardless of the purpose of heat-treating the steel material. For example, there is a purpose of annealing a lump of magnetic powder, a purpose of reflow soldering a plurality of substrates constituting a semiconductor device, or a substrate and a semiconductor element, a purpose of performing nitriding treatment or carburizing treatment on the surface of a workpiece, etc. .

  DESCRIPTION OF SYMBOLS 1 ... Continuous heat treatment furnace, 2 ... Heat treatment chamber, 3 ... Purge chamber, 4 ... Standby stand, 5 ... Pallet, 6 ... Rod, 7 ... Rod, 8 ... Shielding plate, 21 ... Transfer port, 22 ... Partition door, 23 ... Supply port, 24 ... heater, 25 ... vent, 26 ... blower, 31 ... carry-in port, 32 ... partition door, 33 ... exhaust port, W ... work

Claims (2)

A purge chamber;
A heat treatment chamber connected to the side of the purge chamber in the transport direction and provided with a heating device;
A transfer device installed in at least one of the purge chamber or the heat treatment chamber and transferring a plurality of pallets;
In a continuous heat treatment furnace in which a partition door that opens and closes when passing through the pallet is installed at the carry-in port of the purge chamber, the transfer port from the purge chamber to the heat treatment chamber, and the carry-out port of the heat treatment chamber,
The pallet is provided with a shielding plate,
The shielding plate is installed at a pallet end opposite to a transfer direction from the purge chamber to the heat treatment chamber;
A continuous heat treatment furnace.
The continuous heat treatment furnace according to claim 1, wherein the shielding plate is made of a low expansion metal.