JPH07110989B2 - Vacuum processing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vacuum processing apparatus for sequentially performing a plasma carburizing process and an induction hardening process.

[Conventional technology]

Conventionally, as shown in FIG. 3, after performing a gas carburizing process in the heating chamber 21, the crystal grains of the object to be processed W are made fine by cooling with the fan 23 in the cooling section 22, and then the object to be processed W is heated. After returning to the inside of the chamber 21 and heating again, it is lowered into the tank 24 to perform the oil quenching process.

[Problems to be solved by the invention]

However, since the heating chamber 21 and the cooling section 22 are provided in one closed furnace 25, the high temperature gas in the heating chamber 21 flows into the cooling section 22 after gas carburization.
With the fan cooling in the cooling section 22, it takes time to cool the workpiece W, and the grain refinement of the core that has become coarse after carburization becomes insufficient. Therefore, high-quality quenching is not possible and gas carburization and oil Quenching cannot be performed at the same time, and it is necessary to repeat heating and cooling by reciprocating the workpiece W between the heating chamber 21 and the cooling section 22 twice. Therefore, the inefficiency of processing efficiency cannot be avoided.

[Object of the Invention]

The present invention has been made to solve the above-mentioned conventional problems, and plasma carburization and induction hardening in a vacuum processing chamber can be performed independently of each other, and advantages such as plasma carburization (high-speed processing , And uniformity) and parallel processing such as carburizing and quenching to significantly improve the processing quality and efficiency. Furthermore, the object to be processed is carried into the main body without contact with the atmosphere, and each vacuum processing chamber The purpose is to be able to carry in and out.

[Means for solving problems]

The vacuum processing apparatus of the present invention comprises one vacuum transfer chamber 3 and a plurality of vacuum processing chambers 1 provided adjacent to the vacuum transfer chamber 3.
2, an opening 5 for communicating the plurality of vacuum processing chambers 1, 2 with the vacuum transfer chamber 3, and an opening / closing means 4 for opening and closing the opening 5.
And a storage container 9 for storing the object to be processed W, and a loading / unloading port for loading / unloading the storage container 9 into / from the vacuum transfer chamber 3.
30,31 and opening / closing means 32,33 for opening / closing the loading / unloading ports 30,31
And a transfer means 7 that can travel in the vacuum transfer chamber 3 and be positioned to face the opening 5, and the object W to be processed is transferred between the transfer means 7 and the vacuum processing chambers 1 and 2. Transfer means 6 for delivering and receiving via W, supporting means 12, 18 provided in the vacuum processing chambers 1, 2 for supporting the workpiece W delivered by the transfer means 6, and the vacuum transfer chamber 3 And a vacuum suction device connected to the vacuum processing chambers 1 and 2, and an opening 34 for loading and unloading the workpiece W and an opening 34 at the top of the storage container 9. Opening / closing means 8 for opening / closing
Is provided.

〔Example〕

 An embodiment of the present invention will be described below with reference to FIG.

In the figure, 1 is one or a plurality of plasma carburizing furnaces, 2 is one or a plurality of induction hardening furnaces, and vacuum treatments are provided in parallel above one common vacuum transfer chamber 3 independently of each other. Each of the chambers 1 and 2 is provided with an opening 5 that can be opened and closed by a lid 4 on the bottom wall of each chamber.

On the floor of the vacuum transfer chamber 3, on the floor of the vacuum transfer chamber 3 are a plurality of elevating rams 6 that can be moved up and down independently of each other by a cylinder (not shown) at a position directly below the openings 5 of the upper chambers 1 and 2. One or a plurality of trolleys 7 that can travel through the elevator ram 6 can be installed. The trolley 7 is provided with its lifting jack 7A, and on the trolley 7, there is provided a metal cylindrical cover 9 having upper and lower lids 8 and 8'covering the upper and lower openings 34 and 34 '. It can be placed. This cover 9
A gas filling device (not shown) and a gas curtain generator (not shown) that curtain-seals the ram lifting port at the bottom of the container are provided.

Further, the loading / unloading ports 30 and 31 of the vacuum transfer chamber 3 are provided with openable and closable sealing doors 32 and 33, and the transfer conveyors 10 and 11 are provided outside thereof. A vacuum suction device and a gas supply device (not shown) are connected to the vacuum transfer chamber 3.

On the floor surface of the plasma carburizing furnace 1, around the opening 5, there is provided a conductive base 12 that also serves as a cathode and can move back and forth toward the center of the opening 5 by a moving device (not shown), and above the base 12. An anode 13 and a high-frequency coil 14 surrounding the anode 13 and having a tubular shape such as a mesh plate or a perforated plate are arranged concentrically with the opening 5, and the gantry 12 and the anode 13 have a DC power source for discharge.
An AC power supply for high frequency generation (not shown) is connected to the high frequency coil 14. The plasma carburizing furnace 1 is connected to a gas supply device, a vacuum suction device, and an exhaust device, which are not shown, and a cooling coil 16 and a fan 17 capable of supplying cold air into the furnace are provided above the furnace. ing.

On the floor of the induction hardening furnace 2 and around the opening 5, a gantry 18 which is movable toward and away from the center of the opening 5 by a moving device (not shown) is provided. Above the gantry 18, the high-frequency coil is installed. A high-frequency coil 19 connected to the same power source as 14 is arranged concentrically with the opening 5, and the high-frequency coil 19 has a coil inside which is formed in a liquid supply furnace and is provided with a large number of pores (not shown). A quenching liquid spray device is incorporated. Further, a gas supply device and a vacuum suction device, which are not shown, are connected to the induction hardening furnace 2.

[Action]

The object to be processed W is placed on the conductive support table 20, and
Conveyor 1 is housed in a cover 9 with lids 8 and 8 '
After being transferred by 0, the cover 9 is transferred onto the carriage 7 in the transfer chamber 3, and then transferred by the carriage 7 to a predetermined position directly below the plasma carburizing furnace 1.

Next, when the upper lid 8 of the cover 9 is removed and the raising / lowering ram 6 is raised by the rod extension operation of the cylinder, the raising / lowering ram 6 passes through the carriage 7 and the bottom lid 8'of the cover 9 and rises. The processing object W is supported on the lifting ram 6 by a support base.
The whole 20 is transferred and lifted, and is carried into the plasma carburizing furnace 1 through the opening 5.

When the elevating ram 6 reaches the ascending end position, the pedestal 12 is transferred and installed under the support table 20 supported by the elevating ram 6,
When the raising / lowering ram 6 is lowered by the rod shortening operation of the cylinder, the support base 20 is supported on the hearth surface via the base 12,
The object W to be processed is arranged in a central position surrounded by the anode 13 and the high frequency coil 14. The elevating ram 6 descends and returns to its original position, and the opening 5 is closed by the lid 4 (loading into the furnace).

Next, as shown in FIG. 2, the inside of the plasma carburizing furnace 1 is decompressed by the operation of the vacuum suction device to increase the degree of vacuum, and nitrogen gas is supplied by the gas supply device so that the degree of vacuum is approximately 5 × 10 ^-2 -10.
^{When -3} Torr is reached, an AC voltage is applied to the high-frequency coil 14 while maintaining this degree of vacuum to heat the workpiece W by high-frequency heating, and the workpiece W is machined at the A ₃ transformation point during machining. The stress of the plasma is removed and the plasma generation temperature is about 900-1000 ℃
It is heated up to 1100 ° C.

Next, the degree of vacuum is set to approximately 0.1 to 1.0 To
rr, and supplies hydrogen gas as a reducing gas and propane as a carburizing gas, and also treats the workpiece W (cathode)
When a DC voltage is applied between the anode 13 and the anode 13, a negative glow discharge with a high ionization density is stably generated under the above-mentioned degree of vacuum and temperature to turn the gas into plasma, so that plasma carburization can be performed (carburizing period). ).

After the carburization, the discharge is stopped, the degree of vacuum is raised again, and only the high frequency heating is further continued to diffuse and infiltrate more carbon into the surface of the workpiece W (diffusion period).

Next, when the high-frequency heating is stopped and the degree of vacuum is lowered, the cooling coil 16 and the fan 17 are operated to cool and circulate the gas in the furnace, the object W is cooled and coarsened by heating at a high temperature. The crystal grains are refined (gas cooling).

Next, the inside of the induction hardening furnace 2 and the inside of the vacuum transfer chamber 3 are decompressed, and the gas supply device is filled with nitrogen gas,
Opening the opening 5 while curtain-sealing the bottom of the cover 9 and filling the interior of the cover 9 with nitrogen gas, and jacking up the dolly 7 to press it against the furnace bottom, reverse the procedure for carrying in the furnace. Plasma Carburizing Furnace 1
Remove from inside and put in the cover 9 on the dolly 7 and close the lid 8.
Moreover, after the trolley 7 is jacked down and conveyed to a predetermined position directly below the induction hardening furnace 2, the workpiece W is supported in the induction hardening furnace 2 by the pedestal 18 by the same furnace loading procedure as described above. The coil 5 is arranged at the center position surrounded by the coil 19 and the opening 5 is closed. Then, the vacuum suction device is actuated to reduce the pressure in the induction hardening furnace 2 to increase the degree of vacuum, and the degree of vacuum is approximately 5 ×. When the pressure reaches 10 ^-2 to 10 ^-3 Torr, an AC voltage is applied to the high-frequency coil 19 while maintaining this degree of vacuum, and the workpiece W is processed.
Is heated at 750 to 850 ° C. for 5 minutes by high frequency heating, and oil or water or the like is sprayed on the object W to be processed with a quenching liquid spraying device, and the quenching treatment of the object W to be processed is completed. On the other hand, the furnace pressure is returned to the atmospheric pressure around the end of the high frequency heating, the post-treatment opening 5 is opened, and the processed product W ′ is carried out from the induction hardening furnace 2 in the reverse procedure of the furnace carrying-in procedure. Then, the cart 7 is sent to the carry-out conveyor 11. At this time, the cover 9 is removed together with the upper lid 8.

By the way, the above-mentioned work is a case where carburizing and quenching are sequentially carried out, for example, when the plasma carburizing furnace 1 and the induction hardening furnace 2 are one each, but the plasma carburizing furnace 1 and the induction hardening furnace 2 are plural respectively. In some cases, the object W to be treated after the carburization is carried into the induction hardening furnace 2, and the quenching may be performed in parallel with the carburization of the other objects W to be treated.
In such a case, the electric power required for the above work is 400 KW in the carburizing period of plasma carburizing in the plasma carburizing furnace 1 and 200 KW in the diffusing period, while 400 KW in heating and holding in the induction hardening furnace 2 in the diffusing period. Since the electric power can be supplied to the induction hardening furnace 2 for 230 minutes, the induction hardening process is started during the diffusion period while performing the plasma carburizing process due to the independent structure of each furnace, and during the gas cooling or during the gas cooling. Only by doing so, both processes can be performed in parallel by the same high frequency power source.

〔The invention's effect〕

As described above, according to the present invention, since plasma carburization and induction hardening can be performed independently in each vacuum processing chamber, parallel processing such as carburizing and hardening can be performed, and advantages such as plasma carburizing (high speed and uniform processing) can be achieved. In addition to the effective use of the power), the processing quality and efficiency can be significantly improved, and the high-frequency power source can be shared, thereby reducing the facility cost and saving energy. Moreover,
Since the object to be processed is stored in the storage container and carried into the vacuum transfer chamber, and the object to be processed is transferred between the storage container and each vacuum processing chamber in the vacuum transfer chamber, the object to be processed is completely exposed to the atmosphere. It is possible to perform parallel processing such as plasma carburization and induction hardening without performing the above.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a carburizing and quenching treatment operation cycle diagram, and FIG. 3 is a schematic diagram showing a conventional example. 1 ... Plasma carburizing furnace, 2 ... Induction hardening furnace, 3 ... Vacuum transfer chamber, 4 ... Lid, 5 ... Opening part, 6 ... Lifting ram,
7 ... carriage, 8 ... lid, 9 ... closed door, 10,11 ... transport conveyor, 12,18 ... frame, 13 ... anode, 14,19 ... high frequency coil, 15 ... DC power supply, 16 …… Cooling coil, 17 ……
Fans, 20 ... Supporting platform, 30,31 ... Carry-in / out port, 32, 33 ...
Sealing door, 34 ... Opening.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F27B 19/04 F27D 3/12 Z

Claims (1)

[Claims] 1. A vacuum transfer chamber 3, a plurality of vacuum processing chambers 1, 2 provided adjacent to the vacuum transfer chamber 3, a plurality of vacuum processing chambers 1, 2 and the vacuum. An opening 5 that communicates with the transfer chamber 3, an opening / closing means 4 that opens and closes the opening 5, a storage container 9 that stores an object to be processed W, and a loading / unloading of the storage container 9 into / from the vacuum transfer chamber 3. Loading / unloading ports 30 and 31 for
Opening / closing means 32, 33 for opening / closing the carry-in / out ports 30, 31, conveying means 7 that can run in the vacuum transfer chamber 3 and be positioned facing the opening 5, the transfer means 7 and the vacuum processing chamber 1 , 2 to transfer the object W to be processed through the opening 5, and the object W transferred by the transfer means 6 provided in the vacuum processing chambers 1 and 2. Supporting means for pointing 1
2, 18 and a vacuum suction device connected to the vacuum transfer chamber 3 and the vacuum processing chambers 1 and 2, for loading and unloading an object to be processed W on the upper part of the storage container 9. Opening 34
And the opening / closing means 8 for opening / closing the opening 34 is provided.