JPH0599572A - Continuous vacuum furnace - Google Patents

Abstract

PURPOSE:To provide a compact and economical continuous vacuum furnace capable of a cooling speed adjustment over a wide range. CONSTITUTION:A heat insulating chamber 32 surrounded by a heat insulating all 31 is provided in a cooling chamber 14 provided adjoining to a processing chamber for heating an article to be processed, and a vent 35 and an opening/ closing device 38 are provided in and on side walls 34a, 34b of the heat insulating chamber 32. A fan 42 and a cooler 43 are provided on circulation passages 41a, 41b extending from the outside of the side wall 34a through the outside of the heat insulating chamber 32 to the outside of the side wall 34b, and a heater 46 is provided in the heat insulating chamber 32. In rapid cooling the vent 35 is opened and fan 42 is operated. In gradual cooling the vent 35 is closed and heating by the heater 46 is done if necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous vacuum furnace for heating an object to be processed in a vacuum state.

[0002]

2. Description of the Related Art In general, as a continuous type vacuum furnace, a roller hose type vacuum furnace having a structure shown in FIG. 3 is often used.
In the figure, reference numeral 61 is a vacuum sintering furnace for performing a vacuum sintering process, and a vacuum standby chamber 15 in a furnace body 2 and a heating chamber 1 which is a dewax chamber.
6a, a heating chamber 16b which is a sintering chamber, and a cooling chamber 62 are formed. Then, the workpiece 50 charged through the inlet 3 is dewaxed in the heating chamber 16a and then heated in the heating chamber 16b.
Sintering is carried out, and after cooling in the cooling chamber 62, it is taken out of the furnace.
Reference numeral 23 is a heating heater, 63 is a cooler composed of a heat exchanger for cooling the atmospheric gas, and 64 is a stirring fan.

[0003]

In the vacuum sintering furnace 61 having the above-described structure, generally, the cooling chamber 62 is used to take out the sintered product quickly.
In the case of the cooling chamber 62 described above, in the case where it is necessary to perform slow cooling in order to improve the magnetic characteristics such as a sintered product of stainless steel, the rotation speed of the fan 64, for example, in the cooling chamber 62 described above. If the temperature is lowered or the fan 64 is stopped to slowly cool, the fan 64 and the cooler 63 are damaged due to heat radiation from the high temperature sintered product, and slow cooling is difficult. Further, a slow cooling chamber having a heat insulating chamber for slow cooling may be provided in an intermediate portion between the heating chamber 16b and the cooling chamber 14, but in this case, the furnace length becomes long and the installation space is increased.
And the cost of building the furnace are high.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a compact and economical continuous vacuum furnace capable of controlling the cooling rate over a wide range.

[0005]

A continuous vacuum furnace of the present invention is a continuous vacuum furnace in which a cooling chamber is connected to the outlet side of a processing chamber for heating an object to be processed, and a cooling wall is provided inside the cooling chamber. A surrounding heat insulating chamber is provided, and vent holes are formed in both side walls of the heat insulating chamber facing each other, and an opening / closing device for the vent hole is provided, and the outside of one of the side walls is passed through the outside of the heat insulating chamber to the other side. An air blower for circulating the atmospheric gas and a cooler for cooling the atmospheric gas are installed in the circulation path extending to the outside of the side wall.

A heater is preferably installed in the heat insulating chamber.

[0007]

In the continuous vacuum furnace of the present invention, when the object to be treated is to be rapidly cooled, the opening / closing device opens the vent holes on both side walls of the heat insulating chamber, the blower is operated, and the object is cooled by the cooler. By circulating the atmospheric gas through the heat insulating chamber and the circulation path, the object to be processed in the heat insulating chamber is rapidly cooled. Further, if the blower is stopped and the ventilation port is closed, the object to be treated in the heat insulating chamber is gradually cooled, and the blower and the cooler outside the heat insulating chamber are not damaged.

Further, if a desired amount of heat is supplied to the heat insulating chamber by a heater inside the heat insulating chamber, the object to be processed can be cooled at a lower cooling rate, which is suitable for solution treatment and aging treatment of the stainless steel material. is there.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, 1 is a continuous type vacuum sintering furnace, 2 is a furnace body, 3 is an inlet for charging an object to be treated, and 4 is an outlet for taking out the same. 5 is the door of the entrance 3, 6 is the door of the exit 4,
It is adapted to be lifted and lowered by opening / closing devices 7 and 8, respectively. Reference numeral 9 is a transfer roller provided over the entire length of the furnace. The furnace body 2 is divided into three parts, a pretreatment chamber 12, a treatment chamber 13 and a cooling chamber 14 by partition walls 10 and 11, and a vacuum standby chamber 15 and a dewax chamber are provided inside the pretreatment chamber 12 and the treatment chamber 13. Heating chamber 16a, which is a heating chamber 1
6b is formed. Each heating chamber 16a, 16b (hereinafter collectively referred to as the heating chamber 16 and other portions are also collectively referred to).
Is surrounded by a heat insulating wall 17 made of graphite, and its inlet and outlet are opened and closed by a door 18, respectively. Further, in the cooling chamber 14, there is provided a heat insulating chamber 32 which is surrounded on four sides by a heat insulating wall 31 made of graphite, the inlet of which is opened by the door 33 and the outlet of which is opened and closed by the door 6 described above. Reference numeral 20 denotes an opening / closing device for the doors 18 and 33, which connects a frame 21 guided up and down by a guide (not shown) fixed to the furnace body 2 to the piston rod of the air cylinder 22, and links the door 18 to the frame 21 in parallel. And the door 33 is fixed to the frame 21. Reference numeral 23 is a heater made up of an electric heat heater provided in the heating chamber 16.

As shown in FIG. 2, a large number of round hole-shaped ventilation holes 35 are formed in both side walls 34a, 34b of the heat insulating chamber 32, and ventilation holes are formed on the outside of these side walls 34. Mouth 3
5, the doors 36, 36 for opening and closing 5 are guided to be able to move up and down, and the piston rods of the air cylinder 37 for raising and lowering are connected to the upper portions of the doors 36, 36 to open and close the vent 35.
8 is composed. Door 36 has the same size as vent 35,
Same arrangement (however, excluding the bottom vent 35 in FIG. 2)
2 has a vent hole 39, which is raised from the closed state shown in FIG. 2 so that the vent holes 35 and 39 are substantially aligned with each other, and the bottom vent hole 35 in FIG. The vent hole 35 is opened.

In FIG. 2, 41a and 41b are
A circulation path extending from the outside of the side wall 34a to the outside of the side wall 34b of the heat insulating chamber 32, in which 42 is a blower for circulating the atmospheric gas, and 43 is a cooling system including a heat exchanger for cooling the atmospheric gas. It is a vessel. Also, 44 is a suction duct for collecting and guiding the atmospheric gas from the outside of the side wall 34a (more specifically, the outside of the door 36) to the impeller of the blower 42, and 45 is the outside atmosphere of the blown atmospheric gas to the side wall 34b. Is a guide to. In addition, in this embodiment, an electrically heated heater is provided in the heat insulation chamber 32.
A heater 46 is provided. An atmosphere gas supply port 47 is connected to a nitrogen gas supply source (not shown).

In order to perform the vacuum sintering process in the continuous sintering furnace 1 having the above structure, the vacuum standby chamber 15 and the heating chamber 1
6a is set to atmospheric pressure, and the workpiece 50 is loaded into the vacuum standby chamber 15 through the inlet 3. After the vacuum standby chamber 15 and the heating chamber 16a are evacuated to a vacuum state, the object 50 to be processed is heated in the heating chamber 16
Transferred to the inside of a, and the object to be processed 50 is about 60 by the heater 23.
Dewax by heating to 0 ° C. Next, the object to be processed 50
A heating chamber 16b in which a vacuum is applied by the transfer roller 9
Then, the workpiece 50 is heated to about 1400 ° C. and sintered. At this time, the subsequent loading and unloading of the workpiece 50 is performed in the heating chamber 16a.

The object to be treated 50 after sintering is transferred into the heat insulating chamber 32 of the cooling chamber 14, and is then door 33 and the door 36 of the vent 35.
Is closed, and the heater 46 is energized as necessary, and the inside of the heat insulating chamber 32 is maintained at a temperature of about 600 ° C. for a predetermined time to perform an aging treatment. Next, nitrogen gas is introduced from the atmosphere gas supply port 47 to make the inside of the cooling chamber 14 a nitrogen gas atmosphere at approximately atmospheric pressure, and the door 33 is opened by the opening / closing device 38 to open the blower 4
2, the workpiece 50 is rapidly cooled to about 100 ° C. by the nitrogen gas cooled by the cooler 43, and then the door 6 is opened and taken out of the furnace.

When it is desired to rapidly cool the object 50 to be treated from the heating chamber 16b in the cooling chamber 14 as it is, the above-mentioned aging treatment is omitted and the vent hole 35 is immediately opened to blow the blower 4.
2 may be operated to perform rapid cooling.

In the vacuum sintering furnace 1 having the cooling chamber 14 configured as described above, the external dimensions are 900 length × 600 width × 6 height.
After heating 100 kg of the sintered parts loaded on a tray of 00 mm to 1000 ° C. in the heating chamber 16b, they are put into the cooling chamber 14 and heated by the heater 46 as appropriate to raise the temperature of the sintered parts to 550. As a result of performing a test of rapid cooling to slow cooling to ℃, the required cooling time could be adjusted to 6 to 500 minutes. On the other hand, in the conventional vacuum sintering furnace 61 having the cooling chamber 62 shown in FIG.
When the number of rotations was adjusted to 60 to 5 rotations per minute, the required cooling time could only be adjusted to 6 to 15 minutes, and slow cooling for a longer time was impossible. ..

The present invention is not limited to the above embodiment. For example, in the above embodiment, a large number of small-diameter vent holes 35 are arranged in a dispersed manner, so that the object to be treated in the heat insulation chamber 32 can be cooled substantially uniformly. However, the opening / closing device 38 may be of another type in accordance with this. The pretreatment chamber 12 and the treatment chamber 13 may have other configurations than the above. This invention also
In addition to sintering, it can be applied to continuous vacuum furnaces for various purposes such as heat treatment.

[0017]

As described above, according to the present invention,
The cooling rate of the object to be processed in the cooling chamber can be adjusted over a wide range, and a useful continuous vacuum furnace having a wide range of application processing from rapid cooling to slow cooling is provided. In addition, since the rapid cooling and slow cooling are performed in a single cooling chamber, the length of the furnace is shorter and the furnace installation is shorter than when a slow cooling chamber such as an aging chamber and a cooling chamber for rapid cooling are provided separately. The space is small, the furnace construction cost is low, and it is economical.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a vacuum sintering furnace showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a vertical sectional view of a conventional vacuum sintering furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum sintering furnace, 12 ... Pretreatment chamber, 13 ... Treatment chamber, 14
Cooling chamber, 16a ... Heating chamber, 16b ... Heating chamber, 31 ... Insulating wall, 32 ... Insulating chamber, 34a ... Side wall, 34b ... Side wall, 3
5 ... Vent hole, 36 ... Door, 38 ... Opening / closing device, 41a ... Circulation path, 41b ... Circulation path, 42 ... Blower, 43 ... Cooler, 4
6 ... Heater, 50 ... Object to be processed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F27D 9/00 8825-4K

Claims (2)

[Claims] 1. A continuous vacuum furnace in which a cooling chamber is continuously provided on the outlet side of a processing chamber for heating an object to be processed, a heat insulating chamber surrounded by a heat insulating wall is provided in the cooling chamber, and the heat insulating chamber faces each other. Ventilation holes are provided in both side walls, an opening / closing device for the ventilation holes is provided, and an atmosphere is provided in a circulation path from the outside of the one side wall to the outside of the other side wall through the outside of the heat insulating chamber. A continuous vacuum furnace comprising a blower for gas circulation and a cooler for cooling the atmosphere gas. 2. The continuous vacuum furnace according to claim 1, wherein a heater is provided in the heat insulation chamber.