JPS61285381A - Vacuum furnace with partial section heating chamber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) This invention applies high-temperature heat treatment to the workpiece by a heating means provided in the furnace during the process of transporting the workpiece from the entrance of the furnace through the furnace to the exit of the furnace. The present invention relates to a vacuum furnace that is capable of

(Prior art) In this type of vacuum furnace, not only the workpiece is heated by the heating means provided in the furnace, but also the conveyance means for transporting the workpiece is heated. The method requires protection against high temperatures, which complicates the structure, and requires a large amount of thermal energy for heating, which is uneconomical.Furthermore, the temperature distribution inside the furnace is uneven. There was a problem in that the quality of the heat treatment on the object to be treated was likely to deteriorate.

(Problems to be Solved by the Invention) In addition to the above-mentioned conventional problems, the present invention eliminates the need for heat protection measures for the conveying means, simplifies its configuration, and requires less thermal energy for heating. Furthermore, it is an object of the present invention to provide a vacuum furnace that can perform high-quality heat treatment on objects to be treated.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Function) When the table carrying the object to be processed enters from the entrance of the vacuum container, the table is transported by the conveying means to the bottom of the local heating chamber, where the table is lifted by the lifting means and the object to be processed is placed inside the local heating chamber. Place it in place and apply high-temperature heat treatment. Next, when the table is lowered, it is transported again to the next local heating chamber by the transport means, and the same operation is performed there to apply high temperature heat treatment to the workpiece. After repeating these operations and completing the prescribed heat treatment on the object,
The table is sent out to the exit.

(Example) Below, drawings showing examples of the present application will be described. In a sintering furnace 1 shown as an example of a continuous vacuum furnace, 2 is a vacuum vessel which includes a dewaxing chamber 3, a sintering chamber 4, a vacuum cooling chamber 5, a gas cooling chamber 6, a replacement chamber 7, etc. ing. The vacuum container 2 is made of a metal material and can be separated into individual chambers. It can also be water-cooled if necessary. Each room has metal partition walls 8, 8.
It is separated from other rooms by... 9 is the charging port;
10 indicates an export port, 11.11... indicates a communication port, respectively.
They can be opened and closed by doors 12, 13, 14, 14, etc., which can be raised and lowered. Next, 15.15... shows the switching devices of the above-mentioned fields. In this, 16 is a lift frame,
A guide (not shown) attached to the vacuum container 2 allows it to move up and down at a fixed position. 17 indicates a lifting device (for example, an air cylinder) for the lifting frame 16,
18 indicates a parallel link connecting the door and the lifting frame 16;
According to the opening/closing device 15 having such a configuration, the lifting device 17
When the lifting frame 16 is lowered and the door 12 (or 13, 14) faces the charging port 9 (or the carrying port 10, the communication port 11), the lower part of the door is stopped by a receiving member not shown. further lowering of the door is prevented. In this state, when the elevating frame 16 is further lowered, a force is applied to the door that presses it against the periphery of the winter door. As a result, the interior of the vacuum container 2 or the interior of each chamber partitioned by the partition wall 8 is sealed. On the other hand, when the lifting frame 16 rises, the pressing force disappears, and the door opens into the lifting frame 1.
It moves upward with 6 and the winter eyes are released. Next, reference numeral 20 indicates a conveying roller as an example of the conveying means, and each roller is composed of a shaft 22 rotatably attached to the vacuum container 2 by a bearing 21 and a receiving member 23 attached to the shaft 22. One end of the shaft 22 is made to protrude to the outside of the vacuum container 2 through a seal body 24, and a drive device 26 is connected thereto via an interlocking means 25 such as a chain.

Next, in the dewaxing chamber 3, 30 is a local heating chamber attached to the vacuum container 2, which has a storage space 31 for the object to be treated inside and has an open part 32 on the lower surface. This local heating chamber 30 is made of a heat insulating material such as graphite, and its inner surface is designed to reflect radiant heat well. Reference numeral 33 denotes a heating wire exemplified as a heating means attached to the inside of the heating chamber 30, one end and the other end of which are connected to electrodes 34, 34 attached to the vacuum container 2. An infrared lamp may be used as the heating means. 35 is a thermometer attached to the vacuum container 2, and 36 is a viewing window, which are provided to measure the temperature inside the local heating chamber and monitor the internal state thereof. Next, reference numeral 38 indicates a lifting means provided below the local heating chamber 30. In this figure, 40 is a cylinder, which is attached to the vacuum container 2 via the frame 39. A piston rod 41 in the cylinder 40 that can move forward and backward is inserted into the vacuum container 2 through a sealing device W42, and a U-shaped lifting frame 43 is attached to the tip of the rod so that it can rise while avoiding the conveyance rollers. Installation.

Next, the sintering chamber 4 is equipped with a local heating chamber and lifting means similar to those in the dewaxing chamber. Since these have substantially the same configuration as those in the wax removal chamber 3, members that are considered to have the same or equivalent configuration as each member in the wax removal chamber 3 are given the same reference numerals as in the case of the wax removal chamber 3. Omit duplicate explanations. In this sintering chamber 4, since it is necessary to heat the object to an extremely high temperature, a wide electric zone is used as a heating means, and the local heating chamber 30 is made of a material such as molybdenum or tungsten. Next, in the gas cooling chamber 6, 46 is a fan, 47 is a motor, and 48
49 is a cooler, and 49 is a guide plate. When the fan 46 is rotated by the operation of the motor 47, the gas inside flows as shown by the arrow in FIG. It is designed to cool it by coming into contact with it.

Next, 50 indicates a table on which the object to be processed is placed, in which 51 is a base frame, 52 is a shielding plate, 53 is a lid plate, and 54 is a mounting plate, which are spaced apart from each other by a connecting member 55. It is connected with . The mounting plate 54 is made of a material with high heat resistance, and the object to be processed 56 is placed on it. Furthermore, both the shielding plate 52 and the lid vi53 are made of a heat insulating material. These inner cover plates 53 have their own lower part 5 so that the local heating chamber 30 can be thermally sealed.
3a is formed to have a wider area than the open part 32 of the local heating chamber 30, and further includes an upper part 53b that fits inside the open part 32 above the lower part 53a.

Both of these upper portion 53b and lower portion 53a are
In order to obtain high heat resistance and sufficient heat insulation, the upper part 53b is made of laminated tungsten plates, and the lower part 53a is made of laminated molybdenum plates.

Next, reference numeral 58 denotes a transport cart, and the upper surface thereof is equipped with rollers 59 on which the table 50 is placed, and the cart can move in a direction perpendicular to the plane of the paper to transport the object to be processed. It has become.

In the normal operation method of the above-mentioned apparatus, operation is started with the dewaxing chamber 3 brought to atmospheric pressure, while the sintering chamber 4, vacuum cooling chamber 5, and gas cooling chamber 6 are brought to a vacuum state. First, when the door 12 is opened, the table 50 loaded with the workpiece 56 is introduced onto the conveyance roller 20 of the wax removal 3 through the loading port 9, and
is closed again, and the dewaxing chamber 3 is evacuated to a vacuum state. In this state, the cylinder 40 in the lifting means 38 is activated, the piston rod 41 is raised, and the lifting frame 4
3 lifts the stand 50 toward the local heating chamber 30. As a result, the object to be processed 56 placed on the mounting plate 54 is located in the holding space 31 in the local heating chamber 30 as shown in the figure, and the open portion 32 is closed by the cover plate 53. After this happens, the heating wire 33 is energized, and the object to be processed 56 is heated by the radiant heat emitted from the heating wire 33.

This heating is performed, for example, to about 600°C. After the above-described heating has been carried out for a predetermined period of time, the lifting frame 43 is lowered by the cylinder 40, and the table 50 on which the workpiece 5G is placed is again placed on the conveying rollers 20. Next, the door 14 of the communication port 11 between the dewaxing chamber 3 and the sintering chamber 4 is opened, and the table 50 on which the object to be processed is placed is placed on the conveying roller 2.
The above-mentioned field 1 of the 0th order is transported toward the sintering chamber 4 above the 0
4 is closed again, and the platform 50 is raised toward the local heating chamber 30 by the lifting means 38, and the same state as in the case of the dewaxing chamber 3 is achieved. The object to be processed 56 is then heated by the radiant heat emitted from the heating means. The heating is performed at, for example, about 2000°C. After the above-mentioned heating is continued for a predetermined period of time, the table 50 on which the object to be processed 56 is placed is returned onto the conveying rollers 20, the door 14 between it and the vacuum cooling chamber 5 is opened, and the object to be processed is placed on the table 50 again. The table 50 carrying the processed material 56 is sent to the vacuum cooling chamber 5 by the transport rollers 20, where it is cooled to a predetermined temperature.Next, the door 14 between the vacuum cooling chamber and the gas cooling chamber 6 is opened. The table 50 on which the workpiece 56 is placed is conveyed to the gas cooling chamber 6 by conveyance rollers 20 . After the field 14 is closed, cooling gas is introduced to the fan 46 and the cooler 48.
is operated to cool the object 56 to be processed.

When the object to be processed 56 has been cooled to a predetermined temperature in this way, the door 14 between it and the replacement chamber 7 is opened, and the object to be processed 56 is opened.
The table 50 on which 6 is placed is transferred to the replacement chamber 7 by the conveyance rollers 20.
In the 0th-order exchange chamber 7, where the door 14 is closed, the air is exchanged with the atmosphere, and then the door 13 is opened.
The table 50 on which the workpiece 56 is placed is sent out to the next process from the outlet 10.

The above dewaxing chamber 3 may have the same configuration as described above, and two may be provided in a continuous manner along the conveyance path of the processed material.
Further, in FIG. 1, a preliminary sintering chamber having the same structure as the sintering chamber 4 is provided between the dewaxing chamber 3 and the sintering chamber 4, and the workpiece is heated therein to the sintering temperature ( For example 200
Preliminary sintering may be performed at a temperature slightly lower than 0°C (for example, 1600°C).

Furthermore, as the above-mentioned conveying means, a cart may be used as the moving means in place of the conveying rollers in the vacuum container 2 (effects of the invention). If the object to be processed 56 is to be heat-treated, the object to be processed 56 on the stand 50 entered from the inlet 9 of the vacuum container 2 is transported to the lower part of the local heating chamber 30 by the conveying means 2o, and there, the object to be processed 56 on the stand 50 is lifted up by the lifting means 38. 50 is lifted up, placed in the local heating chamber 30 and subjected to high-temperature heat treatment, and when the workpiece 56 on the table 50 is further lowered, it is transferred again to the next local heating chamber 30 by the conveying means 2o. It is possible to repeat a series of operations of transporting the film to the outlet 10 and subjecting it to high-temperature heat treatment there, and then sending it to the outlet 10, which has the effect of being able to perform a series of heat treatments during the process of passing through the vacuum container by the transport means 20.

Moreover, even if the object to be processed 56 is subjected to high-temperature heat treatment as described above, the table 50 is lifted by the lifting means 38, the object to be processed 56 on the table is positioned in the local heating chamber 30, and the table 50 is Since the heating can be carried out with the open part of the local heating chamber 30 closed, the conveying means 20 has the advantage that it is not affected by high temperature heat at all.

This has the effect that the conveyance means does not need protection against high temperatures and its structure can be simplified.

Furthermore, when applying high-temperature heat treatment to the object to be processed 56 as described above, the structure is such that the object to be processed 56 can be heated while being positioned within the local heating chamber 30 and with the opening of the local heating chamber 30 being closed by the table 50. Therefore, the space to be heated to a high temperature can be kept to a minimum necessary and sufficient to contain the object to be processed 56, and the heat sealing property of the space to be heated can be improved. These features are economical as the amount of thermal energy required for heating is minimal, as it only heats a small space, such as a local heating chamber, with thermal efficiency.
The temperature distribution within the local heating chamber is good, which has the effect of enabling high-quality heat treatment of the object to be treated.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal cross-sectional view showing a dewaxing chamber and a sintering chamber in a sintering furnace, and FIG. 2 is a vertical cross-sectional view showing a vacuum cooling chamber, a gas cooling chamber, and a replacement chamber in a sintering furnace. FIG. 3 is a cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 4 is a partial view showing a cross-sectional state taken along the line IV-rV in FIG. 2...Vacuum container, 9...Inlet, lO...Outlet, 5
0... Stand, 20... Conveying means, 30... Local heating chamber, 38... Elevating means. Figure 3 Figure 4

Claims (1)

[Claims] a hollow vacuum container having an inlet and an outlet; a conveying means for conveying a table on which a workpiece is mounted in the vacuum container from the inlet to the outlet; A plurality of tables are arranged above the table along the conveyance trajectory, and each has sufficient space for the workpiece to remain therein, heating means for the workpiece, and has an open bottom surface. comprising a local heating chamber, and a plurality of lifting means disposed below each of the local heating chambers, each of which lifts the platform to a position where it overlaps with an opening on the lower surface of the local heating chamber; A vacuum furnace having a local heating chamber, wherein the table has a sufficient area to adiabatically close the opening of the local heating chamber when lifted by the lifting means.