JP2007297647A - Heat-treatment apparatus and heat-treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-treatment facility and a method therefor, wherein the invasion of the outer air introduced into a temperature-raising chamber accompanying the carry-in of a material to be treated, into a main treating chamber can be reduced or shut out in a simple facility structure without using an expensive non-oxidizing gas. <P>SOLUTION: The heat-treatment apparatus is provided with a temperature-raising chamber 52 which is sectioned with a freely opened/closed door, the main treating chamber 54, a temperature-lowering chamber 56 and a cooling chamber 58, wherein the temperature-raising chamber 52 is provided with a second gas discharge port 14' having a first opening/closing valve 12' in addition to the conventional first gas discharge port 66 for exhausting excessive atmospheric gas, and the cooling chamber 58 is provided with a gas discharge port 18' provided with a second opening/closing valve 16' for opening/closing the valve only the time when the outer air is taken into the temperature-raising chamber. Further, the inner pressure P2 in the main treating chamber is kept higher than the inner pressure P1 in the temperature-raising chamber and the inner pressure P3 in the cooling chamber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus and a heat treatment method for heat treating a material to be heat treated in a heat treatment atmosphere gas.

  In heat treatments such as carburizing and carburizing and nitriding of steel members, in general, in order to avoid oxidation of the steel member surface, a predetermined heat treatment is performed in an atmosphere furnace in which the heat treatment atmosphere is controlled to a non-oxidizing atmosphere. A heat treatment apparatus as shown in FIG.

  In FIG. 4, a heat treatment apparatus 50 includes a temperature raising chamber 52 that raises the material M to be treated from room temperature to a predetermined heat treatment temperature, a main treatment chamber 54 that performs a predetermined heat treatment such as carburizing treatment on the material M, The cooling chamber 58 is provided with a cooling chamber 58 for cooling the treatment material M to an appropriate temperature before cooling, such as quenching, and a cooling tank 58 for quenching oil, etc., and each chamber can be communicated by doors 60, 60,. It is divided into.

  The heat treatment atmosphere gas G1 is, for example, an RX gas that is transformed by mixing air with hydrocarbons such as LPG and natural gas, and is connected to the heating chamber 52 and the main through the introduction ports 64, 64,. It is introduced into the processing chamber 54 and the descending greenhouse 56. Further, the temperature raising chamber 52 and the cooling chamber 58 are provided with exhaust ports 66, and the excess atmospheric gas G1 'is exhausted to keep the internal pressure of each chamber substantially equal and constant. Is maintained in a non-oxidizing atmosphere by the heat treatment atmosphere gas G1.

  In the heat treatment apparatus 50 having the above-described configuration, the material to be processed M placed on the tray 62 is first transferred to the temperature raising chamber 52 by a transfer means (not shown) with the entrance door 51 opened and closed, and a predetermined temperature ( For example, the temperature is raised to 870 to 950 ° C. in the carburizing process. Next, the material to be processed M that has been heated to a predetermined temperature is transferred to the main processing chamber 54 that is heated to the processing temperature by opening and closing the intermediate door 60a, and is transferred to the main processing chamber 54 at a predetermined temperature for a predetermined time. By being held, a desired heat treatment such as carburization is performed. The material M to be processed that has undergone the desired heat treatment is conveyed to the descending greenhouse 56 by opening and closing the intermediate door 60b, and an appropriate temperature (for example, carburizing and quenching in order to suppress the occurrence of distortion due to quenching such as quenching). The temperature is lowered to 800-850 ° C. Subsequently, the material M to be uniformly cooled to a predetermined quenching temperature is opened and closed to the cooling chamber 58 by opening and closing the intermediate door 60c, and at the same time, is put into a quenching oil or the like in the quenching tank 58q to be rapidly cooled. (Quenched). The cooled material to be treated M is pulled out of the quenching tank 58q and is carried out by opening and closing the outlet door 59. That is, a predetermined heat treatment can be applied to the material M to be processed by sequentially conveying the material M carried in from the inlet I in the X direction by the conveying means (not shown) and carrying it out from the outlet II.

  By the way, in this heat treatment apparatus 50, the entrance door 51 is opened and the material M to be processed is carried into the temperature raising chamber 52. For this reason, as shown by the arrow A, outside air containing an oxidizing gas such as oxygen or carbon dioxide (hereinafter simply referred to as outside air) is taken into the heating chamber 52 when the material to be treated is carried. The outside air taken into the temperature raising chamber 52 is rapidly heated and expanded by the inner wall of the temperature raising chamber 52 held at a high temperature, and enters the main processing chamber 54 as indicated by an arrow B through the gap of the intermediate door 60a. . As a result, the material M to be treated, which has been held at a high temperature for a long time, is oxidized, which is a cause of quality deterioration such as grain boundary oxidation in steel.

  In order to avoid such deterioration of the quality of the material to be processed due to the outside air, for example, the following various measures are taken.

  (A) Nitrogen gas is introduced into the temperature raising chamber 52 to dilute the outside air that has entered through the nitrogen gas, and simultaneously block the outside air from entering.

  (B) A frame curtain 72 is provided inside the entrance door 51 to suppress intrusion of outside air due to opening and closing of the entrance door 51.

  (C) The amount of introduced heat treatment atmosphere gas G1 introduced into the temperature raising chamber 52 is increased to replace the intruded outside air with the heat treatment atmosphere gas G1.

  (D) A non-oxidizing gas (inert gas) G2 such as nitrogen or argon is introduced into the temperature raising chamber 52 from the cylinder 74 and the outside air that has entered is replaced with these non-oxidizing gases.

  (E) A reducing gas G3 such as propane or butane is introduced from the cylinder 76 into the temperature raising chamber 52 to decompose the oxidizing gas (oxygen, carbon dioxide) in the outside air into carbon monoxide or the like.

  (F) A replacement chamber 78 is provided in front of the temperature raising chamber 52, and the outside air in the replacement chamber 78 is replaced with a non-oxidizing gas (inert gas) G2 such as nitrogen or argon.

  However, the non-oxidizing gas G2 and the reducing gas G3 used in the countermeasures (a), (d), (e), and (f) are expensive, and the running cost is necessary in the heat treatment that requires a large amount of these gases. Will be greatly increased.

  Further, in the flame seal of the measure (b), the sealing performance is not sufficient only by the flame film, and the invasion of the oxidizing gas (outside air) into the temperature raising chamber 52 from between the flames cannot be prevented.

  Further, when the replacement chamber 78 for replacing the atmosphere is provided as in the measure (f), the equipment cost increases and a space for installing the replacement chamber is required, and the heat treatment apparatus 50 is increased in size and the replacement chamber is increased. Since an additional exhaust facility is required for 78, the facility cost is further increased.

  As described above, the temperature raising chamber 52 and the main processing chamber 54 are partitioned by the openable / closable intermediate door 60a. Since the intermediate door 60a is constantly exposed to high temperatures, the main processing chamber 54 and the temperature increasing chamber 52 are provided. Are not completely sealed and isolated from each other. For this reason, when there is a difference between the internal pressure of the main processing chamber 54 and the internal pressure of the temperature raising chamber 52, the heat treatment atmosphere gas comes and goes through the gap of the intermediate door 60 a. That is, when the internal pressure is increased by introducing a gas such as the non-oxidizing gas G2 or the reducing gas G3 into the temperature raising chamber 52 as in the measures (c), (d), (e), the same as the above. Outside air A containing oxidizing gas also flows into the processing chamber 54.

  That is, the conventional measures (a) to (f) as described above are not always satisfactory, and a simple and inexpensive heat treatment apparatus or heat treatment that can reliably prevent the oxidizing gas from entering the main processing chamber. There was a need for method development.

  The present invention has been made in view of the above circumstances, and without using an expensive non-oxidizing gas with a simple equipment structure, the outside air introduced into the temperature raising chamber as the material to be processed is carried in It is an object of the present invention to provide a heat treatment facility and method capable of reducing or blocking intrusion into the treatment chamber.

  The inventor maintains the internal pressure of the main processing chamber higher than the internal pressure of the temperature raising chamber or the cooling chamber so that the heat treatment atmosphere gas introduced into the main processing chamber always flows out to the temperature rising chamber side or the cooling chamber side. Thus, it was noted that the outside air taken into the heating chamber can be prevented from flowing into the processing chamber.

  That is, the heat treatment method of the present invention is a heat treatment method in which a heat treatment atmosphere gas is introduced into a heat treatment apparatus including at least a temperature raising chamber and a main treatment chamber partitioned by an openable / closable door, and the material to be treated is heat treated. The heat treatment atmosphere gas introduced into the treatment chamber is introduced in a larger amount than the heat treatment atmosphere gas introduced into the temperature raising chamber, and the internal pressure of the treatment chamber is maintained higher than the internal pressure of the temperature raising chamber.

  The heat treatment apparatus of the present invention has an inlet for a material to be processed at one end, an outlet for the material to be processed at the other end, partitioned by an openable / closable door, and a heating chamber disposed from the inlet side toward the outlet side. A furnace body having a main processing chamber and a cooling chamber and / or a cooling chamber, and a transport means for transporting the material to be processed from the inlet to the outlet, are introduced by introducing a heat treatment atmosphere gas into the heating chamber and the main processing chamber. In the heat treatment apparatus for performing heat treatment on the treatment material, the temperature raising chamber includes a first outlet for discharging excess heat treatment atmosphere gas and a second outlet having an opening / closing valve that opens and closes due to a change in the internal pressure of the temperature rising chamber. It is characterized by. The on-off valve can be closed when the internal pressure of the temperature increasing chamber is lower than the internal pressure of the main processing chamber, and can be opened when the internal pressure of the temperature increasing chamber is equal to or higher than the internal pressure of the main processing chamber.

  In addition, the heat treatment apparatus of the present invention has an inlet for the material to be processed at one end and an outlet for the material to be processed at the other end, which is partitioned by an openable / closable door and is arranged from the inlet side toward the outlet side. Furnace body equipped with greenhouse, main treatment room, descending greenhouse and / or cooling room, and conveying means for conveying the material to be treated from the inlet to the outlet, introducing heat treatment atmosphere gas into the temperature raising chamber and the main treatment chamber Then, in the heat treatment apparatus for performing heat treatment on the material to be treated, the descending greenhouse and / or the cooling chamber includes an on-off valve that opens and closes in conjunction with a change in the internal pressure of the temperature raising chamber. The on-off valve is preferably closed when the internal pressure of the temperature raising chamber is higher than the internal pressure of the main processing chamber, and is opened when the internal pressure of the temperature increasing chamber is equal to or lower than the internal pressure of the main processing chamber.

  The heat treatment apparatus of the present invention has an inlet for a material to be processed at one end, an outlet for the material to be processed at the other end, partitioned by an openable / closable door, and a heating chamber disposed from the inlet side toward the outlet side. A heat treatment that includes a furnace body having a main processing chamber and a cooling chamber and / or a cooling chamber, and a conveying means for conveying the material to be treated from the inlet to the outlet, and introduces a heat treatment atmosphere gas to heat treat the material to be treated. In the apparatus, the temperature raising chamber includes a first outlet for discharging excess heat treatment atmosphere gas, and a second outlet having an on-off valve that opens and closes according to a change in the internal pressure of the temperature raising chamber, The cooling chamber includes an on-off valve that opens and closes in conjunction with a change in the internal pressure of the temperature raising chamber.

  In the heat treatment method of the present invention, the amount of heat treatment atmosphere gas (such as RX gas) introduced into the main processing chamber downstream from the temperature raising chamber is increased to keep the inner pressure of the main processing chamber higher than the inner pressure of the temperature raising chamber. Thus, it is possible to prevent the outside air containing the oxidizing gas from entering the main processing chamber and promote the discharge of the outside air (oxidizing gas) from the exhaust port of the temperature raising chamber.

  As described above, in the conventional heat treatment apparatus, the ambient temperature outside air taken into the temperature rising chamber as the material to be processed is charged is heated and expanded by the furnace wall or the like in the temperature rising chamber held at a high temperature, By rapidly increasing the internal pressure of the heating chamber, it enters the processing chamber. However, since the heat treatment apparatus of the present invention includes the second exhaust port provided with the opening / closing valve that opens only when the outside air is introduced into the temperature raising chamber in addition to the first exhaust port of the atmospheric gas, By detecting a sudden change and opening the on-off valve, the outside air taken in can be discharged from the second exhaust port to the outside at once, and the internal pressure can be lowered. Thereby, it is possible to prevent the oxidizing gas from entering the main processing chamber.

  In addition, the heat treatment apparatus of the present invention is provided with an on-off valve that is closed only when outside air is introduced into the temperature rising chamber downstream of the temperature rising chamber and into the exhaust port of the temperature drop chamber or the cooling chamber. For this reason, when outside air is taken into the heating chamber and the internal pressure rises, the open / close valve of the cooling chamber or the cooling chamber can be closed, so the internal pressure of the main processing chamber is kept high against the increase in the internal pressure of the heating chamber. can do. That is, it is possible to prevent the flow of outside air from the temperature increasing chamber to the main processing chamber and to reliably maintain the flow of atmospheric gas from the main processing chamber to the temperature increasing chamber.

  In addition, the heat treatment apparatus of the present invention includes the temperature raising chamber having the second exhaust port provided with the on-off valve and the cooling chamber provided with the on-off valve at the exhaust port, so that when the internal pressure of the temperature raising chamber rises, the cooling chamber At the same time, the outside air can be discharged from the heating chamber. Thereby, it is possible to more reliably prevent the oxidizing gas from entering the main processing chamber.

  As described above, according to the heat treatment apparatus and the heat treatment method of the present invention, it is possible to prevent the oxidizing gas from entering the processing chamber with a simple equipment structure without using an expensive non-oxidizing gas such as nitrogen or argon. Can be suppressed or blocked. Therefore, an inexpensive and high-quality heat treatment material can be produced effectively.

(First embodiment)
In the first embodiment, the conventional heat treatment apparatus shown in FIG. 4 is used, and the heat treatment atmosphere gas introduced into the main processing chamber 54 is introduced in a larger amount than the heat treatment atmosphere gas introduced into the temperature raising chamber 52. This is a heat treatment method in which the heat treatment is performed while maintaining the internal pressure higher than the internal pressure of the temperature raising chamber 52.

  Conventionally, the flow rate g1 of the atmospheric gas G1 introduced into the temperature raising chamber 52, the flow rates g2 and g3 of the atmospheric gas G1 introduced into the main processing chamber 54, and the flow rate g4 of the atmospheric gas G1 introduced into the descending greenhouse 56 are substantially the same amount. Thus, by adjusting the internal pressure of each chamber to be substantially equal, the passage of the atmospheric gas G1 through the intermediate doors 60, 60,.

  However, in the heat treatment method of the present embodiment, the flow rates g2 and g3 of the atmospheric gas G1 introduced into the processing chamber 54 are increased so that the internal pressure P2 of the processing chamber 54 becomes the internal pressure P1 of the heating chamber 52 or the internal pressure of the cooling chamber 58. Set to be higher than P3.

  For example, in the case of carburizing treatment of steel members (main treatment temperature: 870 to 950 ° C.), the internal pressure P2 of the main treatment chamber is set to 10 to 100 mmAg (water column), and the differential pressure Δp1 (P2) between the heating chamber and the main treatment chamber -P1) is about 5 to 100 mmAg. This is because if Δp1 is less than 5 mmAg, it is difficult to completely prevent the outside air from entering the main processing chamber, and if it exceeds 100 mmAg, high sealing performance of the entire furnace body is required, resulting in equipment limitations. Because there is. Moreover, it is desirable that the differential pressure Δp2 (p2−p3) between the cooling chamber and the main processing chamber is about 5 to 100 mmAg. If Δp2 is less than 5 mmAg, the gas in the processing chamber flows toward the cooling chamber, which is not preferable because the effect of suppressing the invasion of the oxidizing gas from the heating chamber may be reduced. On the other hand, if it exceeds 100 mmAg, high sealing performance of the entire furnace body is required, and equipment restrictions may occur, which is not appropriate.

  In this way, by maintaining the internal pressure P2 of the main processing chamber 54 higher than the internal pressure P1 of the temperature raising chamber 52 and the internal pressure P3 of the cooling chamber 58, the outside air taken into the temperature rising chamber as the material to be processed is carried is brought into the main processing chamber. Can be prevented from entering.

(Second Embodiment)
2nd Embodiment is the heat processing apparatus 1 shown in FIG. 1 which provided the discharge port which discharges external air in the temperature rising chamber of the conventional heat processing apparatus. In FIG. 1, the same parts as those in FIG.

  The heat treatment apparatus 1 has an inlet I for the material to be processed at one end and an outlet II for the material to be processed M at the other end, and is divided into a heating chamber 52, a main processing chamber 54, a descending greenhouse 56, which are partitioned by an openable / closable door. A furnace body F having a cooling chamber 58 and transporting means (not shown) for transporting the material to be processed M through the furnace body F from the inlet I to the outlet II are provided. The temperature raising chamber 52 of the heat treatment apparatus 1 is provided with a second exhaust port 14 having an on-off valve 12 in addition to the conventional first exhaust port 66 that discharges excess atmospheric gas.

  This on-off valve 12 is opened only when the outside air taken in when the material to be processed M is charged rapidly expands to increase the internal pressure P1, and the internal pressure P1 in the temperature raising chamber is lower than the internal pressure P2 in the main processing chamber. It is designed to close. Therefore, even in the conventional heat treatment method in which the internal pressure P1 of the temperature raising chamber and the internal pressure P2 of the main processing chamber are substantially equal, when the taken-in outside air suddenly expands and the internal pressure P1 rises, it opens and closes immediately. Since the valve 12 can be opened to release the outside air, the entry of the outside air into the processing chamber can be reduced. When the internal pressure P1 of the temperature raising chamber is higher than the external pressure, there is no intrusion of outside air into the temperature raising chamber, so that the on-off valve 12 is opened even if the internal pressure P1 of the temperature raising chamber is higher than the internal pressure P2 of the main processing chamber. do not have to.

  This on-off valve 12 can be configured to be electrically controlled by a sensor that measures the internal pressure P1 of the temperature raising chamber 52 and an electromagnetic valve. Moreover, it is good also as a mechanical on-off valve using urging | biasing force, such as a spring which opens at predetermined internal pressure P1 or more.

  In the present embodiment, the inner diameter of the second discharge port is 1 to 5 times the inner diameter of the first discharge port (50 mm in the present embodiment). If the inner diameter of the second discharge port is less than 1 time, the introduced outside air cannot be efficiently discharged and replaced with the heat treatment atmosphere gas in a short time. On the other hand, when the pressure is larger than five times, the outside air may flow backward from the second discharge port when the internal pressure P1 is lower than the atmospheric pressure. More preferably, it is 1.5 to 3 times.

  Further, in the present embodiment, by applying a heat treatment method for maintaining the internal pressure P2 of the main processing chamber higher than the internal pressure P1 of the temperature increasing chamber as in the first embodiment, the intrusion of outside air into the main processing chamber is prevented. Further reduction can be achieved.

(Third embodiment)
3rd Embodiment is the heat processing apparatus 2 shown in FIG. 2 provided with the on-off valve which opens and closes in response to the change of the internal pressure of the temperature rising chamber 52 in the cooling chamber 58 of the conventional heat processing apparatus. In FIG. 2, the same parts as those in FIG.

  The heat treatment apparatus 2 has an inlet I of the material to be processed at one end and an outlet II of the material to be processed M at the other end, and is divided into a heating chamber 52, a main processing chamber 54, a cooling chamber 56, which are defined by an openable / closable door. A furnace body F having a cooling chamber 58 and transporting means (not shown) for transporting the material to be processed M through the furnace body F from the inlet I to the outlet II are provided. The cooling chamber 58 of the heat treatment apparatus 2 is provided with an exhaust port 18 having an opening / closing valve 16 that closes only when outside air is taken into the temperature raising chamber 52 instead of the conventional exhaust port 66.

  This on-off valve 16 can be configured to be electrically controlled by a sensor for measuring the internal pressure P1 of the temperature raising chamber and a solenoid valve. Further, as indicated by a dotted line 20, a mechanical on-off valve may be used that uses an urging force such as a spring that communicates with the inside of the temperature rising chamber 52 through a pipe or the like and is driven by a change in the internal pressure P1 of the temperature rising chamber 52.

  The on-off valve 16 is normally open, and in this open state, the atmospheric gas G1 flowing from the main processing chamber 54 through the temperature drop chamber 56 and the oily smoke generated during quenching are discharged from the discharge port 18. However, when the material to be treated M is newly charged and the outside air is taken into the temperature raising chamber 52, the on-off valve 16 is closed by detecting the increase in the internal pressure P1, so that the heat treatment atmosphere gas is indicated by the arrow C. Thus, it flows from the cooling chamber 58 in the upstream direction. Accordingly, it is possible to prevent outside air from entering the processing chamber 54. The on-off valve 16 is closed only when low-temperature outside air is taken in and it is desired to create a flow of atmospheric gas from the main processing chamber to the temperature rising chamber side, and the internal pressure P1 of the temperature increasing chamber is the internal pressure P2 of the main processing chamber. When the oxidizing gas does not flow into the processing chamber because it is equal to or lower than Therefore, the excess heat treatment atmosphere gas and the like are discharged as usual due to the difference between the internal pressure P3 of the cooling chamber and the atmospheric pressure, so that the backflow of the outside air to the cooling chamber does not occur.

  Also in the present embodiment, as in the first embodiment, by applying a heat treatment method in which the internal pressure P2 of the main processing chamber is maintained higher than the internal pressure P1 of the heating chamber or the internal pressure P3 of the cooling chamber, the main processing is performed. Intrusion of outside air into the chamber can be further reliably prevented.

(Fourth embodiment)
FIG. 3 shows a fourth embodiment in which a discharge port for discharging outside air is provided in a temperature raising chamber of a conventional heat treatment apparatus, and a cooling valve 58 is provided with an opening / closing valve that opens and closes in conjunction with a change in the internal pressure of the temperature raising chamber 52. It is the heat processing apparatus 3 shown.

  The heat treatment apparatus 3 has an inlet I for the material to be processed at one end and an outlet II for the material M to be processed at the other end, and is divided into a heating chamber 52, a main processing chamber 54, a descending greenhouse 56, which are partitioned by an openable / closable door. A furnace body F having a cooling chamber 58 and a transport means (not shown) for transporting the material to be processed M through the furnace body F from the inlet I to the outlet II are provided. The temperature raising chamber 52 of the heat treatment apparatus 3 is provided with a second exhaust port 14 ′ having a first on-off valve 12 ′ in addition to the conventional first exhaust port 66 that discharges excess atmospheric gas. The cooling chamber 58 is provided with an exhaust port 18 ′ having a second on-off valve 16 ′ that closes only when outside air is taken into the temperature raising chamber 52.

  The first on-off valve 12 is opened only when the outside air taken in when the material to be processed M is charged rapidly expands to increase the internal pressure P1, and the internal pressure P1 in the temperature raising chamber is higher than the internal pressure P2 in the main processing chamber. When it is low, the valve is closed. The second open / close valve is configured to close when the internal pressure of the temperature raising chamber is higher than the internal pressure of the main processing chamber, and to open when the internal pressure of the temperature increasing chamber is equal to or lower than the internal pressure of the main processing chamber. Yes.

  Therefore, according to the heat treatment apparatus of the present embodiment, when the material to be processed M is carried into the temperature raising chamber 52 and outside air is taken in and the internal pressure P1 rises, the second on-off valve 16 is closed and the first on-off valve 12 is simultaneously closed. Open the valve. Then, as shown by the arrow C, the heat treatment atmosphere gas can flow upstream from the cooling chamber 58, and the rapidly expanded outside air is discharged from the second discharge port 14 in a short time. Accordingly, it is possible to reliably prevent the outside air from entering the processing chamber.

  Also in the present embodiment, as in the first embodiment, by applying a heat treatment method in which the internal pressure P2 of the main processing chamber is maintained higher than the internal pressure P1 of the heating chamber or the internal pressure P3 of the cooling chamber, the main processing is performed. Intrusion of outside air into the chamber can be prevented even more reliably.

  The heat treatment method and heat treatment apparatus of the present invention are not limited to the above embodiment, and may be changed without departing from the gist of the present invention. For example, in the first embodiment, the heat treatment method has been described for a heat treatment apparatus having a temperature raising chamber, a main treatment room, a descending room, and a cooling room. However, the heat treatment apparatus is not limited to such a type of heat treatment apparatus. However, what is necessary is just to provide at least a temperature raising chamber and a main processing chamber.

  In the above embodiment, an oil tank is provided in the cooling chamber to perform oil quenching, but gas quenching using a cooling gas may be used. In addition, the heat treatment apparatus does not necessarily have a cooling chamber. In the heat treatment apparatus, only a heat treatment such as carburization may be performed, and a quenching process may be separately performed by induction hardening or the like.

  In the above-described embodiment, the temperature raising chamber is provided with the second discharge port having the on / off valve in addition to the conventional first discharge port. However, the opening degree of the on / off valve is adjusted by changing the internal pressure P1, so that the second The discharge port can also serve as the first discharge port.

  Moreover, in the said embodiment, although the on-off valve which opens and closes according to the change of the internal pressure P1 of a temperature rising chamber was provided in the cooling chamber, the same effect can be acquired even if it provides in a descending room. In addition, you may provide this on-off valve in both a descending greenhouse and a cooling room.

  The present invention can be suitably used for carburizing and quenching treatment of steel members and carburizing and nitriding quenching treatment.

It is a schematic block diagram which shows the structure of the heat processing apparatus of 2nd Embodiment. It is a schematic block diagram which shows the structure of the heat processing apparatus of 3rd Embodiment. It is a schematic block diagram which shows the structure of the heat processing apparatus of 4th Embodiment. It is a schematic block diagram which shows the structure of the conventional heat processing apparatus.

Explanation of symbols

12: (first) on-off valve 14: second discharge port 16: (second) on-off valve 18: exhaust port 52: heating chamber 54: main processing chamber 56: descending chamber 58: cooling chamber 58q: quenching tank 60: intermediate Door 62: Heat treatment atmosphere gas generator
A: Outside air F: Furnace body M: Material to be treated

Claims (6)

In a heat treatment method for introducing a heat treatment atmosphere gas into a heat treatment apparatus including at least a temperature raising chamber and a main treatment chamber partitioned by an openable / closable door,
The heat treatment atmosphere gas introduced into the main processing chamber is introduced in a larger amount than the heat treatment atmosphere gas introduced into the temperature rising chamber, and the internal pressure of the main processing chamber is maintained higher than the internal pressure of the temperature rising chamber. A heat treatment method. There is an inlet for the material to be treated at one end and an outlet for the material to be treated at the other end, which is partitioned by an openable / closable door, and is arranged from the inlet side toward the outlet side, the main treatment room, the cooling room, A furnace body with a cooling chamber;
A heat treatment apparatus for carrying out heat treatment on the material to be treated by introducing a heat treatment atmosphere gas into the temperature raising chamber and the main treatment chamber.
The temperature raising chamber has a first discharge port for discharging excess heat treatment atmosphere gas;
A heat treatment apparatus comprising: a second discharge port having an on-off valve that opens and closes according to a change in internal pressure of the temperature raising chamber.   The open / close valve is closed when the internal pressure of the temperature raising chamber is lower than the internal pressure of the main processing chamber, and is opened when the internal pressure of the temperature rising chamber is equal to or higher than the internal pressure of the main processing chamber. The heat processing apparatus as described in. A heating chamber, a main processing chamber, a cooling chamber, and an outlet of a processing material at one end, an outlet of the processing material at the other end, partitioned by an openable / closable door, and arranged from the inlet side toward the outlet side. A furnace body with a cooling chamber;
A heat treatment apparatus comprising a transfer means for transferring the material to be processed from the inlet to the outlet, and introducing a heat treatment atmosphere gas into the temperature raising chamber and the main processing chamber to heat-treat the material to be processed.
The heat-treating apparatus, wherein the descending chamber and / or the cooling chamber includes an on-off valve that opens and closes in conjunction with a change in the internal pressure of the heating chamber.   5. The on-off valve closes when the internal pressure of the temperature raising chamber is higher than the internal pressure of the main processing chamber, and opens when the internal pressure of the temperature rising chamber is equal to or lower than the internal pressure of the main processing chamber. The heat treatment apparatus as described. There is an inlet for the material to be treated at one end and an outlet for the material to be treated at the other end, which is partitioned by an openable / closable door, and is arranged from the inlet side toward the outlet side, the main treatment room, the cooling room, A furnace body with a cooling chamber;
A heat treatment apparatus comprising a conveying means for conveying the material to be treated from the inlet to the outlet, and introducing a heat treatment atmosphere gas to heat treat the material to be treated;
The temperature raising chamber includes a first outlet that discharges the excess heat treatment atmosphere gas, and a second outlet that has an on-off valve that opens and closes due to a change in the internal pressure of the temperature raising chamber,
The heat-treating apparatus, wherein the descending chamber and / or the cooling chamber includes an on-off valve that opens and closes in conjunction with a change in the internal pressure of the heating chamber.

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