JP3868411B2 - Multi-chamber heat treatment furnace - Google Patents

Description

  The present invention relates to a heat treatment apparatus for a processed member.

  When carburizing and quenching a steel workpiece, a series of steps such as pre-cleaning, carburizing, oil quenching, post-cleaning, and tempering are performed. When performing vacuum quenching of a mold member or the like, gas cooling is performed following the vacuum heating. Moreover, when sintering powder metallurgy members, such as a metal and a ceramic, a series of processes, such as binder burn-off, heating, slow cooling, and cooling, are performed. In carrying out these series of processes, as a heat treatment facility conventionally used, each batch type processing apparatus for carrying out each process or two processes is arranged independently, or those series of processes are continuously performed. In order to carry out, there is a continuous processing facility in which the processing chambers are connected in series.

  The batch-type carburizing and quenching furnace is equipped with a front chamber and a heating chamber, and a quenching oil tank equipped with lifting means is provided at the lower part of the front chamber. After being kept soaked for a predetermined time in the chamber, it is transported to the front chamber and immediately quenched with oil. The member to be treated after oil cooling is lifted onto the quenching oil tank by the elevating means, drained in the front chamber, and then carried out of the apparatus. Next, the member to be treated is carried into a separately installed washing machine, the quenching oil is washed and removed, dried and then carried out, put into a separately installed tempering furnace, and subjected to a tempering process there.

  The single-chamber vacuum quenching furnace includes a heating mechanism and a gas cooling device in a single chamber, and a member heated at a quenching temperature for a predetermined time immediately performs gas cooling in the same chamber.

  In the case of batch sintering equipment, there are one in which all processes from burn-off to sintering and cooling are performed in the same chamber, and one in which a burn-off furnace and a sintering furnace are separately installed. In the latter case, the member to be processed enters the cooling step in the same chamber immediately after the sintering step. Note that, unlike the above two examples, the cooling rate after sintering is not so much a problem because there are not many requirements on the characteristics of the product to be processed.

  In the case of a continuous processing facility, each process is assigned to a separate processing chamber or processing area and the passage time or residence time of each chamber, and multiple processes are performed in the same processing chamber like a batch processing facility. It will never be.

  In the case of a conventional batch type carburizing and quenching furnace, it is necessary to increase the number of installed furnaces in order to increase the processing amount, but the number of quenching oil tanks is also automatically increased. However, the time required for oil quenching and oil draining is usually significantly shorter than the time for carburizing, diffusion and soaking. In other words, the utilization efficiency of the quenching oil tank is extremely low. Therefore, it was a facility with poor investment efficiency. The same can be said for the anterior chamber-related transport mechanism, lifting means, gas piping, exhaust piping, exhaust system such as a vacuum pump, control valve such as an electromagnetic valve, and measuring equipment such as a pressure gauge. In addition, since loading and unloading between multiple batch devices is performed by a track carriage traveling in front of each device, not only the equipment cost but also the installation area is large, and it is dangerous if the operator neglects to travel the cart, There was a problem such as.

In the case of a conventional single-chamber type vacuum quenching furnace, two means having opposite functions in the same room, namely, a heat-sealed heat insulating means comprising a heater and a heat insulating material, and a circulating cooling comprising a gas introduction pipe, a fan and a gas cooler. And a third means for switching both functions depending on the process. This complicates the internal configuration of the apparatus, increases the dimensions of the apparatus, and increases the cost. In addition, when the production volume is increased by this apparatus, the number of installed units is increased. However, considering that the heating time is longer than the gas cooling time for quenching, the circulation cooling means and the switching means for the same reason as described above. There was a problem that usage efficiency was low.
In addition, since not only the member to be treated but also the heat insulation means are cooled at the time of cooling, it is necessary to adopt a cooling means having a large capacity in order to achieve the constant cooling rate required for the object to be treated. In addition, there is a need to compensate for the heat storage loss of the heat insulation member due to cooling during the heat treatment of the next batch, and extra energy is required.

  In the case of a single-chamber sintering furnace, the flow and exhaust of the furnace atmosphere so that binders and molding lubricants that volatilize from the powder metallurgy member at the time of burn-off do not contaminate furnace members such as high-temperature sintering furnace members and heat insulating materials. A special configuration in consideration of the route is required, which is a factor of high device cost. Nevertheless, since contamination of the furnace material is unavoidable, especially in the low temperature part, it is necessary to volatilize and remove the contamination by emptying the equipment at a high temperature at regular intervals or every certain number of times between operations. It was. Therefore, there is a problem that productivity is not increased and extra energy is required.

  In order to solve the problem of including components and functions with low utilization efficiency, which becomes apparent when a plurality of batch furnaces and single chamber furnaces are operated as described above, a continuous processing facility has been considered. That is, in the continuous processing apparatus, the capacity and residence time for each series of processing chambers are designed according to a predetermined processing amount. Therefore, it does not include components and functions with low utilization efficiency such as batch furnaces and single chamber furnaces. The utilization efficiency is 100% in every part during steady operation. In addition, each processing chamber or processing area only needs to be configured to perform necessary and sufficient actions for each processing, and two different functions such as a batch furnace and a single-chamber furnace that do not work simultaneously coexist. Since it is not necessary to take a configuration, a design without waste is possible.

  However, the continuous processing apparatus has the following problems. When the processing amount is reduced from the initial plan, that is, from the equipment design standard, the equipment utilization rate decreases in a linear relationship with time after the last charging of the processed goods, and is zero when the processing of the last processed goods is completed. Therefore, after that, the operation of the apparatus is temporarily stopped. Next, in order to resume the operation of the apparatus again, in order to achieve a long-term continuous operation with high utilization efficiency, it is necessary to stock up the products to be processed, and thus a considerable waiting time, that is, an apparatus downtime occurs. Become. Therefore, in such a production situation, the apparatus utilization efficiency that should be high originally in a continuous processing apparatus is significantly lower than that in the case of a batch furnace or a single chamber furnace. Therefore, the continuous processing apparatus is not suitable for high-mix low-volume production in which the amount is difficult to be collected and many types of workpieces are handled.

  The present invention has been made to eliminate the above-described drawbacks of the conventional apparatus, and the object of the present invention is to provide a heat treatment furnace having high utilization efficiency of the apparatus components and suitable for high-mix low-volume production. There is to do.

The present invention provides a plurality of processing chambers, a vacuum purging front chamber for loading / unloading an object to be processed, and a processing chamber or a front chamber capable of rotating around a vertical axis and being processed. A main transfer chamber for storing a main transfer means for transferring an object and a cooling unit for moving the object to be moved up and down and a means for moving the object to be moved up and down between the cooling unit ; The plurality of processing chambers and the front chamber are arranged in parallel so as to be replaceable with respect to a connection port arranged so as to be in circumferential contact with the same cylindrical surface coaxial with the vertical rotation axis with respect to the main transfer chamber. The multi-chamber heat treatment furnace is characterized in that it is connected and the plurality of processing chambers include a burn-off chamber.

In the multi-chamber heat treatment furnace configured as described above, since the plurality of processing chambers and the front chamber share one main transfer chamber, the use efficiency of the main transfer chamber during operation is high, and the occupied floor area is also large. Can save. Similarly, since the plurality of processing chambers share the front chamber via the main transfer chamber, the use efficiency of the front chamber is high and the occupied floor area can be saved. In addition, since the plurality of processing chambers and the front chamber are connected and arranged in parallel to the main transfer chamber, a plurality of different processing can be performed concurrently in accordance with the case, and the plurality of processing chambers are arranged in time series. Can be used for continuous processing. Furthermore, the plurality of processing chambers and the front chamber are connected to the main transfer chamber so as to be replaceable with respect to a connection port arranged so as to be in contact with the same cylindrical surface coaxial with the vertical rotation axis of the main transfer means. Therefore, the number, type, and relative position of the processing chamber and the front chamber can be freely selected according to the purpose. Since the workpiece is loaded into and out of the apparatus through the front chamber that can be vacuum purged, a frame curtain is not required. Since conveyance between a series of processes can be performed in a narrow space in the apparatus, it is possible to save an installation place of the vehicle traveling outside the furnace and the track. Further, since not only the auxiliary components relating to the main transfer chamber and the front chamber but also the control portion are integrated and shared for a plurality of processing chambers, the utilization efficiency thereof can be improved. In addition, since the burn-off chamber is included in multiple processing chambers, the process including the process of removing volatile components such as binders and molding lubricants and the process of burn-off such as dewaxing is performed together with other series of processes. Can do.
In addition, since a cooling unit and a means for moving the workpiece up and down between the cooling unit and the cooling unit are added to the main transfer chamber, a three-dimensional arrangement is possible and the occupied floor area can be saved. In addition, the object to be processed can be quickly transferred between the processing chamber and the cooling chamber.

In the multi-chamber heat treatment furnace, the multi-chamber heat treatment furnace may be a sintering furnace.
In this case, a sintering process including a series of steps such as dewaxing, vacuum sintering, and cooling sequentially performed in the sintering furnace can be performed.

In the multi-chamber heat treatment furnace, the processing chamber may be provided with a mechanism for pushing out an object to be processed into the main transfer chamber.
In this case, the object to be processed is pushed directly onto the lifting / lowering means of the main transfer chamber by the pushing mechanism provided in the processing chamber, so that the object to be processed can be quickly transferred.

  According to the present invention, the equipment cost is lower than before, the utilization efficiency is high, the occupied floor area is small, a safe and clean heat treatment furnace can be realized, and the load variation of the workpiece can be flexibly dealt with. In addition, a heat treatment furnace that is particularly suitable for high-mix low-volume production can be provided. In addition, the processing chambers can be freely combined and connected, so that an optimum equipment configuration corresponding to the purpose of the object to be processed such as sintering including burn-off can be achieved.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a planar arrangement when the multi-chamber heat treatment furnace of the present invention is configured for vacuum sintering. The workpiece is taken in and out from the vacuum purge chamber (1). Then, after the vacuum purge and the return pressure by nitrogen gas, it is transferred into the main transfer chamber (2). The main transfer means (3) of the main transfer chamber (2) is rotatable in a horizontal plane and can be stopped at a position facing any of the surrounding chambers. A fork type that can be carried into another room is preferred. In addition, each chamber and the main transfer chamber are isolated by a door (not shown) so that the door is opened only when it is necessary to transfer the workpiece. Now, the workpieces transferred into the main transfer chamber (2) are moved through the main transfer chamber (2) in the order of the burn-off chamber (4), the first vacuum sintering chamber (5), and the cooling chamber (7). After passing through the first predetermined process consisting of dewaxing, vacuum sintering, and cooling, when returning to the main transfer chamber (2) again, it finally passes through the vacuum purge chamber (1). Then it is carried out of the furnace. Usually, the cooling is performed by a combination of natural cooling and gas cooling, but of course not limited thereto.

  Similarly, the second object to be processed is carried in, in order of the burn-off chamber (4), the second vacuum sintering chamber (6), and the cooling chamber (7) through the main transfer chamber (2), After the second predetermined process is completed, it is carried out of the furnace through the main transfer chamber (2) and the vacuum purge chamber (1). Similarly, the third, fourth,... Workpieces are processed. In this example, the two vacuum sintering chambers (5) and (6) have a vacuum purge chamber (1), a burn-off chamber (4), and a cooling chamber (7), respectively, for sintering with a relatively long process time. The balance of process capability is aimed at by taking the structure of continuous, but other combinations can be freely set according to the process. The main transfer chamber (2) and the main transfer means (3) are shared by the five chambers, thereby further improving the use efficiency. In some cases, the number of rooms may be reduced. Here, as described above, the first and second workpieces are not necessarily subjected to the same processing. Further, for example, the first vacuum sintering chamber (5) may be operated with temporally changing parameters. The same applies to the other rooms. Unlike the case of the continuous furnace, the processing chambers are arranged in parallel, so that the degree of freedom in changing the processing conditions is high even when a series of processing is performed continuously.

FIG. 2 shows the main transfer chamber (2) of the multi-chamber heat treatment furnace of the present invention, the main transfer means (3), the quenching chamber (8) above the main transfer chamber (2), and the first lifting / lowering means (9). It is an elevation view which shows the structure which arranged. The first object to be treated is sintered in the first vacuum sintering chamber (5), and then transferred to the first lifting / lowering means (9) waiting in advance in the main transfer chamber (2), and immediately cooled rapidly. The chamber (8) is lifted and cooling is started. During the cooling of the first object to be processed, the vacuum sintering chamber (5) transfers the second object to be processed which has finished the process in the burn-off chamber (4) to the main transfer means (2) via the main transfer means (2). 3) and start a new sintering process.
The same applies to the second vacuum sintering chamber (6). The cooling chamber (7) can be replaced with another processing chamber, or it can be used as two independent cooling chambers as it is. In terms of arrangement, the quenching chamber (8) is particularly suitable for gas cooling. Of course, the quenching chamber (8) may be replaced with a normal cooling chamber.

  FIG. 3 shows a planar arrangement when the multi-chamber heat treatment furnace of the present invention is configured for carburizing and quenching. The vacuum purge chamber (1), the main transfer chamber (2), the main transfer means (3), One carburizing and quenching chamber (10), a second carburizing and quenching chamber (11), a cleaning chamber (14), and a tempering chamber (15) are shown. Moreover, FIG. 4 shows that in the same configuration example, the main transfer chamber (2) includes a main transfer means (3), a quenching oil tank (12), and a second lifting / lowering means (13) below the main transfer chamber (2). It is the elevation which showed the arrangement which arranged. After the workpiece is transferred to the main transfer chamber (2) through the vacuum purge chamber (1), the first carburizing and quenching chamber (10) or the second carburizing and quenching chamber (11), and the quenching oil tank (12). , Through the main transfer chamber (2), cleaning chamber (14), and tempering chamber (15) in this order, finishing a series of steps consisting of carburizing, diffusion, soaking, oil quenching, oil draining, degreasing, and tempering. Are again carried out to the outside through the vacuum purge chamber (1).

  Here, returning to the explanation of the operation at the time of quenching, the first workpiece to be carburized and diffused in the first carburizing and quenching chamber (10) and then held at the quenching temperature for a predetermined time is the main transfer. In the chamber, it is conveyed onto the second lifting / lowering means (13) waiting in advance, immediately lowered into the quenching oil tank (12), and oil-quenched. At this time, an unillustrated push-out mechanism provided in the carburizing and quenching chamber (10) is used to quickly transfer the workpiece to the main transfer chamber (2). Quenching in oil needs to be performed quickly, but if this is done by the main transfer means (3), it is necessary to move the workpiece to the carburizing and quenching chamber (10), compared to the extrusion mechanism. This is because it takes extra time. During the oil quenching of the first workpiece, the first carburizing and quenching chamber (10) passes the second workpiece to be waited in the vacuum purge chamber (1) through the main transfer chamber (2). Received from the main conveying means (3), a new carburizing and quenching process is started. The same applies to the second carburizing and quenching chamber (11). This configuration is particularly suitable for rapid quenching in oil and quenching in water. In some cases, jet quenching with water or oil may be performed. In that case, a liquid jet quenching chamber (not shown) may be used instead of the quenching oil tank (12) in the lower part of the main transfer chamber (2).

  For the above reasons, in the case of this example, the main transfer means (3) does not necessarily have to be of a fork type, but is an extrusion mechanism and is not only a carburizing and quenching chamber (10) (11) but also a cleaning chamber. Of course, (14), the tempering chamber (15) and the vacuum purge chamber (1) may each be provided with an extrusion mechanism. The above is the case of the carburizing and quenching furnace, but the same applies to the case of the vacuum gas cooling and quenching furnace. That is, although not shown, the workpiece soaked at the quenching temperature in the vacuum heating chamber is quickly transferred onto the first lifting means in the main transfer chamber by the extrusion mechanism provided in the vacuum heating chamber, It is pushed up to the quenching chamber and immediately gas cooled and quenched. The quenching gas quenching chamber is not limited to the upper portion of the main transfer chamber, and a separate lower portion or upper and lower portions may be provided.

  Next, based on a carburizing furnace whose effective dimensions in the furnace are 24 inches wide, 36 inches deep and 24 inches high, the occupied floor area of the furnace of the configuration of this embodiment is compared with that of a conventional batch furnace line equivalent thereto. To do. In the case of the conventional batch furnace line, the occupied floor area is 84 square meters, whereas in the configuration of this embodiment, it is 41 square meters. In other words, in the case of this configuration, it is possible to install facilities with the capacity of two conventional batch furnaces on the same floor area.

FIG. 5 shows a planar arrangement when two units A and B are connected as one example of the expansion of the multi-chamber heat treatment furnace of the present invention. That is, A and B are connected to each other by the connecting chamber (16), and each of A and B has a vacuum purge chamber (1). In this configuration, for example, the vacuum purge chamber (1) of A is used as the inlet of the object to be processed, and that of B is used as the outlet, and the arrangement of each processing chamber is changed as the object to be processed moves from A to B. It can be aimed at so-called sequential use in which the processing ends. Alternatively, the arrangement of the processing chambers may be equivalent to A and B, and the processing chambers may simply be used in parallel. The point to be noted here is that even in the case of a highly sequential arrangement, since it is parallel in each of A and B, it is possible to operate with a much higher degree of freedom than conventional continuous furnaces. On the contrary, even in the case of a highly parallel arrangement, the degree of freedom of processing is far greater than when operating independently without connecting A and B, and thus compared to the conventional batch furnaces. It is to increase. As a result, processing can be performed with more combinations, and the utilization efficiency of the entire apparatus can be further increased.
Although not shown, if the number of connections is increased, the layout can be linear, circular, mesh, or any shape.

  Here, the connection chamber (16) is thermally insulated in some cases. For example, when a workpiece heated to a high temperature is conveyed between AB, heat insulation is necessary. In addition, the number and position of the entrances and exits can be freely selected. For example, instead of one vacuum purge chamber (1) in each of FIGS. 5A and 5B, an appropriate processing chamber is installed, and instead of the connecting chamber (16), one long side and the other two sides are included. If another type of vacuum purge chamber (not shown) having a door that can be opened on each side surface is arranged, the structure can exchange the outside and the object to be processed through one long side door.

It is a plane layout view showing a first embodiment of the present invention. It is an elevational view showing a second embodiment of the present invention. It is a plane layout view showing a third embodiment of the present invention. It is a principal part elevational view of the 3rd Example of this invention. FIG. 6 is a plan layout view showing a fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum purge chamber 2 Main transfer chamber 3 Main transfer means 4 Burn-off chamber 5 First vacuum sintering chamber 6 Second vacuum sintering chamber 7 Cooling chamber 8 Rapid cooling chamber 9 First raising / lowering means 10 First carburizing and quenching chamber 11 Second carburizing and quenching chamber 12 Quenching oil tank 13 Second lifting means 14 Washing chamber 15 Tempering chamber 16 Connection chamber

Claims (3)

A plurality of processing chambers, a vacuum purging front chamber for loading / unloading a processing target, and a vertical chamber capable of rotating around the vertical axis to transfer the processing target between the processing chambers or the front chamber A main transfer chamber for storing a main transfer means for moving up and down and a means for raising and lowering the object to be processed between the cooling part and the cooling part. A plurality of processing chambers and anterior chambers are connected and arranged in parallel so as to be replaceable with respect to the connection ports arranged so as to be circumferentially connected to the same cylindrical surface coaxial with the vertical rotation axis with respect to the main transfer chamber, A multi-chamber heat treatment furnace wherein the plurality of processing chambers include a burn-off chamber.   The multi-chamber heat treatment furnace according to claim 1, wherein the multi-chamber heat treatment furnace is a sintering furnace. The multi-chamber heat treatment furnace according to claim 1 or 2, wherein a mechanism for extruding the workpiece into the main transfer chamber is provided in the processing chamber.

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