JP2003171717A - Two-chamber type heat treatment furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, two-chamber type heat treatment furnace in which the consumption of the atmospheric gas is small and the cooling speed is high. <P>SOLUTION: This two-chamber type heat treatment furnace in which a furnace body 1 having a predetermined inner surface shape is partitioned into a heating area 1A and a cooling area 1B comprises: the furnace body 1 in which the furnace wall of the heating area is formed of an insulating structure, a furnace wall of the cooling area is formed of a water-cooling structure, a first door 5 is provided on one end part of the heating area, and the other end part of the cooling area is formed of an open structure; a muffle 8 which has the outline substantially identical to the inner surface shape of the furnace body, is provided with a heating means 9 inside, and is closed by a rear side wall 11 having a second wall on one end part on the first door side and an atmospheric exhaust pipe 12 and an atmospheric gas feed pipe 13 on the other end part; and a moving mechanism 14 to move the muffle between the heating area and the cooling area in the furnace body. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-chamber heat treatment furnace. 2. Description of the Related Art Heat treatment furnaces for subjecting a treatment material to heat treatment are roughly classified into a multi-chamber type and a single-chamber type. As a multi-chamber heat treatment furnace, a two-chamber type heat treatment furnace comprising a heating chamber for performing heat treatment and a cooling chamber for cooling and charging and extracting the processing material, and a charging chamber for the processing material are provided. And a cooling chamber for cooling and extracting the processing material. In the multi-chamber heat treatment furnace, it is necessary to independently control the furnace temperature or the atmosphere of the heating chamber and the cooling chamber. Therefore, an intermediate door is provided to partition each chamber. At the same time, the intermediate door is opened and closed to move the processing material, and heat treatment is performed for each chamber. Here, as an example, a two-chamber type heat treatment for performing a gas sulfide nitriding treatment will be described with reference to FIG. This two-chamber type gas sulphonitriding furnace T 'has two cooling / charging / extraction chambers 20 and a heating processing chamber 30. An intermediate shut-off section 40 is provided between the two chambers. And
At the opening of the cooling and charging / extracting chamber 20, an inlet blocking section 5
0 is provided. The cooling and charging / extraction chamber 20 has a cooler 2
1, a cooling circulation fan 22, a processing material support roller 23, a processing material transfer device 24, and an intermediate roller 25 are provided, and a vacuum exhaust pipe 26 and a N ₂ gas supply pipe 27 for pressure recovery are connected. When the processing material W is moved between the two chambers, the intermediate roller 25 is tilted horizontally so as to bridge between the rollers on both sides, and in other cases, the intermediate roller 25 is rotated until it becomes vertical as shown in the figure. It is movably provided. The vacuum exhaust pipe 26 is connected to a vacuum pump VP via an on-off valve V1 and to a processing gas incinerator GI via an on-off valve V2. The N ₂ gas supply pipe 27 is connected to an N ₂ gas supply source (not shown) via an on-off valve V3 and a pressure reducing valve VR. The heat treatment chamber 30 has an atmosphere circulation fan 3
1, a processing material support roller 32 and an electric heater 33 are provided, and a process gas introduction nozzle 34 is provided in which the ejection ports are uniformly distributed over the entire lower portion of the processing material support roller 32. Further, a vacuum exhaust pipe 35 and a purge N ₂ gas supply pipe 36 are connected to the upper part of the heat treatment chamber 30.
The sulfided gas supply pipe 37 is connected to the process gas introduction nozzle 34.
Is connected. The furnace wall of the heat treatment chamber 30 is formed of a heat insulating material, and a stainless steel plate which has been subjected to a corrosion-resistant treatment (eg, Almar processing) is disposed on the surface of the heat insulating material. In addition, as for the components in the heat treatment chamber 30, in principle, a stainless steel material subjected to a corrosion-resistant treatment is used. The vacuum exhaust pipe 35 is connected to a vacuum pump VP via an on-off valve V4. The N ₂ gas supply pipe 36 is connected to the secondary side of the pressure reducing valve VR via the on-off valve V5. An oxynitriding gas supply pipe 37 is provided with an on-off valve V
6, V7 and a flow meter F1 connected to the secondary side of the pressure reducing valve VR, and a pipeline between the on-off valves V6 and V7 is connected to a NH ₃ gas supply source (not shown) via the flow meter F2 and the on-off valve V8. It is connected to an H ₂ S gas supply source (not shown) via a mass flow controller MC and an on-off valve V9. An intermediate shut-off section 40 is provided in the heat treatment chamber 3 facing the boundary between the cooling and charging / extraction chamber 20 and the heat treatment chamber 30.
0 is provided with an intermediate door 41 which moves forward and backward with respect to the opening of
The intermediate door 41 is lifted up by the lifting / lowering means 42 in a state in which the intermediate door 41 is retracted from the opening of the heat treatment chamber 30 toward the cooling / loading / extraction chamber 20, and can be retracted from the moving space of the processing material W. The entire drive mechanism of the intermediate door 41, including the intermediate door 41 and the lifting / lowering means 42, is housed in the door hood 43 and is shielded from the outside. Except during the movement of the processing material W between the two chambers, the opening of the heat treatment chamber 30 is closed by an intermediate door 41, and the two chambers are isolated from each other in atmosphere. On the surface of the heat insulating material of the intermediate door 41, a stainless steel plate which has been subjected to a corrosion-resistant treatment (eg, Almar processing) is disposed. The inlet blocking section 50 is provided with a charging / extracting door 52 which is moved up and down by driving a fluid pressure cylinder 51. The charging / extracting door 52 is closed while the charging / extracting door 52 is closed.
The airtightness in the extraction chamber 20 is maintained. Next, the nitrosulphurizing process in the two-chamber gas sulphonitriding furnace T 'will be described. First, the charging / extracting door 52 is opened to transfer a plurality of processing materials W from the outside of the furnace to a predetermined position in the cooling / charging / extracting chamber 20, then the charging / extracting door 52 is closed, and heating is performed in this state. The inside of the processing chamber 30 and the inside of the cooling / loading / extracting chamber 20 are evacuated to a predetermined pressure (about 1 Torr) through the vacuum evacuation pipes 26 and 35, and the insides thereof are vacuum-purged. After the completion of the vacuum purging, the intermediate door 41 is opened, the intermediate roller 25 is tilted horizontally, and the processing material W is transferred from the cooling / loading / extracting chamber 20 into the heating processing chamber 30. Rotate until it is in the state
1 is closed and a predetermined pressure (about 0.5 Torr)
Evacuate to r). After the completion of the vacuum purging in the heat treatment chamber 30, N ₂ gas is supplied into the cooling and charging / extraction chamber 20 and the heat treatment chamber 30 through N ₂ gas supply pipes 27 and 36, respectively. atmosphere circulation fan 3 under N ₂ gas atmosphere with pressure recovery inside to a predetermined pressure (about 650 Torr) of
1, the heating of the processing material W is started by forced convection heating, and in this state, the temperature is increased to a predetermined temperature (about 350 ° C.) to be uniform. Under this uniform temperature condition, the inside of the heat treatment chamber 30 is evacuated again to a predetermined pressure (about 0.5 Torr) through the vacuum exhaust pipe 35, and then the N ₂ gas supply pipe 3 is introduced into the heat treatment chamber 30.
Supplies N ₂ gas through 6, supplied uniformly and dispersing a mixed gas of H ₂ S gas and NH ₃ gas from below the treatment material support roller 32 via the sulphonitrided gas supply pipe 37. In addition, the supply of each of the above-mentioned gases brings the inside of the heat treatment chamber 30 into a substantially atmospheric pressure state, and at the same time, brings the temperature to the sulphinitriding treatment temperature. Then, this state is maintained for a predetermined time and the processing material W
To form a nitrosulphurized layer on the surface. After the formation of this oxynitrided layer, the interior of the cooling / charging / extraction chamber 20 and the interior of the heat treatment chamber 30 are evacuated to a predetermined pressure (about 1 Torr) through the vacuum exhaust pipes 26 and 35, and both chambers are evacuated. Are set to substantially the same pressure, the intermediate door 41 is opened, and the intermediate roller 25 is tilted horizontally.
From the cooling and charging / extraction chamber 20 to the intermediate roller 2
The intermediate door 41 is closed by rotating the intermediate door 5 until it becomes vertical. The cooling and charging / extraction chamber 20 contains N ₂
The N ₂ gas is supplied through the gas supply pipe 27 to restore the pressure in the room to approximately the atmospheric pressure and to operate the cooler 21 while operating the cooling circulation fan 22 to cool the processing material to a predetermined temperature by forced convection cooling. I do. After the cooling step is completed, the charging / extraction door 52 is opened, the processing material W is carried out of the furnace, the charging / extraction door 52 is closed, and a series of sulphonitriding processes is completed. As is clear from the above description, in a multi-chamber heat treatment furnace, an intermediate door is an essential component for partitioning each chamber, so that an intermediate shut-off portion is required. However, there is a problem that the heat treatment furnace becomes larger (installation space becomes larger). Further, since the intermediate door is provided only in the heating chamber, and the cooling / loading / extracting chamber and the intermediate shut-off portion are always in communication, the supply / exhaust of the cooling / loading / extracting chamber is performed. The amount increases. That is, since the processing material cannot be moved between the chambers unless the atmosphere and pressure of each chamber are the same, a large amount of atmosphere must be supplied and exhausted every time the processing material moves.
There is a problem that the consumption of the atmosphere increases and the time required for the heat treatment increases accordingly. When the heat treatment step in the two-chamber heat treatment furnace is performed in a one-chamber heat treatment furnace for the purpose of saving space, both the heat treatment and the cooling treatment are performed in the same treatment chamber. In addition to the processing material, it is necessary to raise the temperature of the processing chamber of the heat insulation structure, and in the subsequent cooling step, in addition to the processing material, the temperature of the processing chamber having a large heat capacity also needs to be lowered. In order to maintain it, the heating and cooling capacity must be increased. That is, in a one-chamber type heat treatment furnace, heating means
There was a problem that the capacity of the cooling means had to be very large. Therefore, the present invention suppresses the supply and exhaust amount and heat capacity of the atmosphere by moving the muffle itself between the heating area and the cooling area of the furnace main body to perform the heating and cooling treatments, thereby saving energy. It is another object of the present invention to provide a two-chamber heat treatment furnace capable of saving space by omitting an intermediate door. In order to achieve the above object, the present invention provides a two-chamber heat treatment furnace in which a furnace body having a predetermined inner surface shape is divided into a heating zone and a cooling zone. A furnace body having a heat insulating structure for the furnace wall in the heating area, a water cooling structure for the furnace wall in the cooling area, a first door at one end of the heating area, and an open structure at the other end of the cooling area; It has an outer shape substantially the same as the inner surface shape of the furnace main body, is provided with a heating means inside, has a second door at one end on the first door side, and has an exhaust gas pipe and an atmosphere gas supply pipe at the other end. And a moving mechanism for moving the muffle between a heating area and a cooling area in the furnace main body. Next, an embodiment of a two-chamber heat treatment furnace according to the present invention will be described with reference to FIGS. The two-chamber heat treatment furnace T according to the present invention generally includes a furnace main body 1, a muffle 8, and a moving mechanism 14. The furnace main body 1 has a predetermined shape such as a cylindrical shape or a square shape, and a heating zone 1A having a furnace wall formed of a heat insulating material 2 and having a heat insulating structure, and a furnace wall formed of a water cooling jacket 3, for example. The cooling zone 1B is formed into a water-cooled structure, and is installed on a base (not shown). A first door 5 is attached to an open end of the heating area 1A so as to be openable and closable.
Is open without a door. Reference numeral 4 denotes a seal member. A first opening 6 having an open end is provided above the cooling zone 1B, while the heating zone 1A is open.
A second opening 7 is provided in the lower part of the cooling area 1B over both areas. Since the muffle 8 is mounted on the mounting member 18 of the moving mechanism 14 described below and located in the furnace main body 1,
It has substantially the same shape as the furnace main body 1 and has a heating means 9 such as an electric heater inside, and a second door 10 made of a heat insulating material is attached to the opening on the first door 5 side so as to be openable and closable. Is closed by a rear wall 11 made of a heat insulating material. The rear wall 11 has an exhaust pipe 12 for exhausting the atmosphere in the muffle 8 and an atmosphere gas (N ₂ gas) or a oxynitriding gas (H ₂ S gas, NH ₃ gas) in the muffle 8.
A plurality of atmosphere gas supply pipes 13 for supplying gas), and the exhaust pipe 12 communicates with the exhaust device (not shown) outside the furnace body 1 from the first opening 6 while the atmosphere gas supply pipe 13 is cooled. The other end opening of the area 1B communicates with each atmosphere gas supply source. The moving mechanism 14 is for moving the muffle 8 between the heating zone 1A and the cooling zone 1B in the furnace main body 1 and a rail 15 mounted below the furnace main body 1.
And a support member 17 installed on the rail 15 via a sliding member 16 and a mounting member 18 provided on the support member 17 for supporting the muffle 8. The support member 17 is provided with a driving device such as a cylinder (not shown) for moving the muffle 8 forward and backward.
It is designed to retreat. Next, a method of operating the two-chamber heat treatment furnace T having the above-described configuration will be described. First, in the state of FIG.
After opening the first door 5 and the second door 10 and loading the processing material W into the muffle 8, the doors are closed and an exhaust device (not shown) is driven to drive the muffle 8 through the exhaust pipe 12.
The inside is evacuated to a predetermined pressure (for example, about 0.5 Torr). Thereafter, N ₂ gas is supplied from the atmosphere gas supply pipe 13 into the muffle 8 and the oxynitriding gas (N
_{2 S} gas and NH ₃ gas) Fukuoshi to substantially atmospheric pressure inside the muffle 8 by supplying, to form a sulfonitriding layer immersed in a surface treatment material W by maintaining a sulphonitriding treatment temperature for a predetermined time. As described above, when the nitrosulphidation layer forming process is completed, the inside of the muffle 8 is evacuated to a predetermined pressure (for example, about 1 Torr), and then N ₂ gas is supplied into the muffle 8 to clean the inside of the muffle 8. Return to atmospheric pressure. Thereafter, the muffle 8 is moved to the cooling area 1B by driving a cylinder or the like (the state shown in FIG. 2).
Is cooled to a predetermined temperature. When the cooling of the processing material W is completed,
The muffle 8 is moved to the heating area 1A, and the first door 5 is moved.
Then, the processing material W is carried out of the furnace by opening the second door 10. In the above description, the case of performing the nitrosulphurizing treatment in the two-chamber heat treatment furnace T has been described. However, the present invention is not limited to this, and the heat treatment is performed while switching the furnace atmosphere. If so, for example, blackening
Of course, any heat treatment can be performed. Further, the exhaust pipe 12 may be made to protrude from the other end opening of the cooling area 1B in the same manner as the atmospheric gas supply pipe 13 without providing the first opening 6. Further, the moving mechanism 14 is also provided with the second opening 7.
May be laid in the furnace main body 1 without providing the muffle 8, and the muffle 8 may be reciprocated by, for example, a cylinder, a chain, or the like. As is apparent from the above description, the two-chamber heat treatment furnace according to the present invention can be downsized because it is a two-chamber heat treatment furnace but has no intermediate shut-off portion. Further, since there is no intermediate shut-off portion and the atmosphere is supplied and exhausted only in the muffle, the consumption of the ambient gas can be greatly reduced, the supply and exhaust time is shortened, and the one-chamber type is used. Since the heating zone and the cooling zone are different from those cooled after heating in the heat treatment furnace, there is no need to cool down to the heat insulating material in the heating zone, and the cooling rate can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a two-chamber heat treatment furnace according to the present invention in a heated state. FIG. 2 is a sectional view of the two-chamber heat treatment furnace according to the present invention in a cooled state. FIG. 3 is a cross-sectional view of a conventional two-chamber heat treatment furnace. [Description of Signs] 1 furnace body, 1A heating area, 1B cooling area, 2 heat insulating material, 3 water cooling jacket, 5 first door, 6 first opening, 7 second opening, 8-muffle, 9-heating means, 1
0 to 2nd door, 11 to rear wall, 12 to exhaust pipe, 13 to atmosphere gas supply pipe, 14 to moving mechanism, T to 2 chamber type heat treatment furnace,
W to processing material.

Claims (1)

Claims: 1. A two-chamber heat treatment furnace in which a furnace body having a predetermined inner surface shape is divided into a heating region and a cooling region, wherein the furnace wall of the heating region has a heat insulating structure, and a cooling region. The furnace wall has a water-cooled structure, and a first door is provided at one end of the heating area.
A furnace body having an open structure at the other end of the cooling area; an outer shape substantially the same as the inner surface shape of the furnace body, a heating means provided inside, and a second end provided at one end on the first door side.
A muffle having a door closed by a rear wall provided with an atmosphere exhaust pipe and an atmosphere gas supply pipe at the other end; and a movement mechanism for moving the muffle between its heating area and the cooling area in the furnace body. And a two-chamber heat treatment furnace.