JPH0336518Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a single-chamber vacuum heat treatment furnace that performs heating and cooling within the same furnace.

Conventionally, as a single-chamber vacuum heat treatment furnace for performing vacuum annealing treatment, for example, Japanese Utility Model Publication No. 41-17532 has been put into practical use.

As shown in FIG. 1, this heat treatment furnace is equipped with an inner chamber 2 (heating chamber) having an opening/closing damper 3 in a furnace shell 1 equipped with a water-cooled jacket. A cooling tube 4 is provided between the inner chamber 2, a heater 5 and a circulation fan 6 within the inner chamber 2, and an inert gas supply pipe and a vacuum exhaust system (not shown).

At the time of heat treatment, after charging the treatment material W into the inner chamber 2 from a door (not shown),
The processing material W in the inner chamber 2 is heated by the heater 5 while maintaining the inside of the furnace under a predetermined reduced pressure, and when the predetermined heating is completed, the damper 3 is opened and cooling water is supplied to the cooling tube 4. The processing material W is cooled and heat-treated while circulating the atmosphere in the furnace by the circulation fan 6. In addition, due to the structure of a single-chamber furnace, air enters the furnace when the door is opened (charging/extracting materials), and impurities in the air adhere to the internal materials of the furnace, such as the cooling tube 4 and the furnace inner wall surface 1a. It turns out.

Therefore, in the structure described above, the adhered impurities are vaporized by the temperature increase of the cooling tube 4, the furnace inner wall surface 1a, and other furnace internal members due to the high temperature atmosphere at the initial stage of cooling, and contaminate the furnace atmosphere.

Therefore, there was a drawback that the surface of the treated material was oxidized. Furthermore, since the inner chamber 2 is provided within the furnace shell 1, the structure is complicated.

This invention was developed to eliminate the drawbacks of the conventional single-chamber vacuum heat treatment furnace, and the inner chamber is eliminated by forming a heating chamber by lining the inner surface of the furnace shell with a heat insulating material. Provided is a simple, single-chamber vacuum heat treatment furnace in which impurities adhering to materials inside the furnace are vaporized and discharged to the outside of the furnace when the door is opened by vacuum purging the inside of the heating chamber when the furnace temperature rises. The purpose is to

Next, the present invention will be explained with reference to FIG. 2 and subsequent figures showing one embodiment.

In the heat treatment furnace according to the present invention, a heating chamber 8 is constructed by lining the inner surface of a furnace shell 1 with a heat insulating material 7, and a cooling tube 4, a heater 5, and a circulation fan 6 are provided in the heating chamber 8. It has a configuration in which an evacuation system 10 consisting of an active gas supply pipe 9, a mechanical booster 11, and a rotary pump 12 is provided.

As shown in the heat cycle shown in FIG. While raising the temperature, the inside of the heating chamber 8 is intermittently vacuum purged (approximately 10 ^-2
←→approximately 50 Torr) to heat and vaporize impurities adhering to the furnace interior materials such as the cooling tube 4 when charging the processing material W, and heat the processing material W while discharging it to the outside of the furnace.

When the inside of the heating chamber 8 reaches a predetermined temperature, inert gas is supplied into the heating chamber 8 so that the inside of the heating chamber 8 reaches about 650 Torr, and the furnace temperature is maintained at a constant temperature. When a predetermined period of time has elapsed, the heater 5 is stopped, a refrigerant is supplied into the cooling tube 4, the processing material W is cooled while the furnace atmosphere is circulated by the circulation fan 6, and the processing material W is then extracted. be.

As is clear from the above explanation, according to the present invention, an inner chamber is provided inside the furnace and no cooling tube is disposed outside of the furnace as in the conventional case, so the structure is simple and the furnace can be replaced with a conventional one. In addition to being more compact, the cooling tube and other internal materials are heated when the temperature of the heating chamber rises, and impurities that adhere to the door are vaporized when the door is opened and closed. No impurity gas is generated in the early stage of cooling, and oxidation of the treated material can be prevented.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional single-chamber vacuum heat treatment furnace.
FIG. 2 is a sectional view of a single-chamber vacuum heat treatment furnace according to the present invention, and FIG. 3 is a heat cycle of the furnace. 1-furnace shell, 4-cooling tube, 5-heater, 6-circulation fan, 7-insulation material, 8-heating chamber,
9 - Inert gas supply pipe, 10 - Vacuum exhaust system.

Claims (1)

[Scope of utility model registration request] In a single-chamber heat treatment furnace equipped with a cooling tube, the furnace shell is lined with a heat insulating material to form a heating chamber, and the cooling tube is installed inside this heating chamber. A single-chamber vacuum heat treatment furnace, characterized in that it is connected to a vacuum exhaust system that vacuum-purges the inside of the heating chamber when the internal temperature rises.