Tank-type pre-vacuumizing nitriding furnace

Abstract

The utility model relates to the technical field of heat treatment workpieces, in particular to a tank type pre-vacuumizing nitriding furnace. The containing cavity is erected in the hearth, and a gas circulation cavity is formed between the outer wall of the containing cavity and the inner wall of the hearth. A gas circulating device is also arranged; one end of the accommodating cavity is communicated with the gas circulation cavity; the other end of the accommodating cavity is communicated with a gas inlet of the gas circulating device; a gas outlet of the gas circulating device is communicated with the gas circulating cavity; a vacuumizing device for vacuumizing the hearth is further arranged, a vacuumizing pipe of the vacuumizing device is communicated into a cavity of the hearth, and uniformity and high efficiency of workpiece nitriding are guaranteed in a gas circulation mode.

Description

Technical Field

[0001] The present application relates to the technical field of heat treatment of workpieces, in particular to a nitriding furnace. Background Art

[0002] In order to improve the surface hardness, wear resistance and corrosion resistance of the workpiece, the workpiece needs to be nitrided. Nitriding treatment generally requires a nitriding furnace to provide a high temperature and a certain pressure nitrogen environment.

[0003] However, in general nitriding furnaces, there is a tendency for gas to remain in the furnace, which results in an oxide layer forming during nitriding of the workpiece, leading to uneven nitriding. In addition, the thermal conductivity of the gas is poor, and the heat in the furnace is unevenly distributed. The nitrogen may also be unevenly distributed, resulting in uneven thickness or unstable quality of the nitriding layer on the workpiece surface. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the name of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the name of the utility model, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0007] The furnace is also provided with a receiving cavity for placing workpieces;

[0008] The accommodating chamber is arranged in the furnace, and a gas circulation cavity is arranged between the outer wall of the accommodating chamber and the inner wall of the furnace;

[0009] A gas circulation device is also provided;

[0010] One end of the accommodating cavity is connected to the gas circulation cavity; the other end of the accommodating cavity is connected to the gas inlet of the gas circulation device;

[0011] The gas outlet of the gas circulation device is connected to the gas circulation cavity;

[0012] A vacuuming device for evacuating the furnace is also provided, and a vacuuming pipe of the vacuuming device is connected to the furnace cavity.

[0013] Firstly, the utility model optimizes the nitriding furnace. After the optimization, a gas circulation device is used in the furnace of the nitriding furnace to drive the nitrogen to circulate in the furnace, so that the workpiece in the accommodating cavity is in the circulating nitrogen, thereby improving the uniformity and stability of the nitrogen distribution in the furnace. Secondly, the circulating gas can also help to transfer heat to the surface of the workpiece more evenly, thereby ensuring that the temperature and nitrogen are evenly distributed when the workpiece is heated, making the nitriding process more uniform and efficient. Finally, a vacuum pumping device is also connected to the furnace to extract the air in the furnace before nitriding in the nitriding furnace. Excluding oxygen or other impurity gases can reduce oxidation and pollution in the metal nitriding process, thereby improving the quality of the nitriding layer.

[0014] Preferably, the gas circulation device also includes an impeller and a rotating shaft, and the rotating shaft links the driving motor of the gas circulation device and the impeller; the furnace is provided with a through hole, and the rotating shaft passes through the through hole and is connected to the impeller; a sealed bearing is provided at the matching position of the rotating shaft and the through hole, the fixed ring of the sealed bearing is fixedly connected to the inner wall of the through hole, and the rotating ring of the sealed bearing is matched with the rotating shaft; the utility model optimizes the gas circulation device, and a sealed bearing is also provided at the matching position of the rotating shaft and the through hole to prevent air leakage from the furnace, so that the nitrogen in the furnace will not leak, and the air pressure in the furnace will remain stable after the temperature is constant, thereby improving the nitriding quality of the workpiece.

[0015] Preferably, the sealed bearing is made of silicon nitride ceramic material; the utility model optimizes the sealed bearing, and the sealed bearing made of silicon nitride ceramic material after optimization can work under the high temperature and high pressure environment of the nitriding furnace.

[0016] Preferably, a contraction port is provided at one end of the accommodating chamber close to the gas circulation device, and the contraction port is aligned with the air inlet of the gas circulation device; the utility model optimizes the accommodating chamber for placing the workpiece. After the optimization, a contraction port is provided in the accommodating chamber in the furnace opposite to the air inlet of the gas circulation device, so that the air circulation device inhales air from the hole of the contraction port and exhausts air along the outer edge of the contraction port, so that the gas circulates along the inside and outside of the accommodating chamber, making the gas circulation trajectory clear and smooth.

[0017] Preferably, the accommodating cavity is provided with a support frame, one end of the support frame is fixed to the inner wall of the furnace, and the other end of the support frame is inserted into the accommodating cavity to support the workpiece placed therein; using the support frame to support the accommodating cavity improves the stability of the accommodating cavity and facilitates the stable placement of the workpiece into the accommodating cavity.

[0018] Preferably, a control valve is further provided in the vacuum tube of the vacuum pumping device, and the control valve controls the connection of the vacuum tube; the utility model optimizes the vacuum pumping device, and after the optimization, a control valve is provided in the vacuum tube, the vacuum tube is connected when the vacuum pumping device is operating, and the vacuum tube is closed after the vacuum is drawn to prevent nitrogen leakage in the furnace.

[0019] Preferably, the gas circulation device uses an impeller made of silicon carbide ceramic material, the center of the impeller close to one end of the accommodating cavity is the air inlet of the gas circulation device, and the circumference of the impeller is the air outlet of the impeller; the impeller made of silicon carbide ceramic has the advantages of high temperature resistance, high hardness, and wear resistance, and can operate continuously and stably in high-temperature heat treatment equipment, ensuring the continuous, stable and long-term operation of the gas circulation device in the furnace of the nitriding furnace.

[0020] Preferably, a heat-insulating layer of aluminum silicate wool material is also provided in the cavity of the furnace shell, and the heating device is suspended between the heat-insulating layer and the furnace; the heat-insulating layer of aluminum silicate wool material ensures that the temperature of the furnace shell will not continue to rise and cause danger, and that the heating of the furnace will not cause uneven heating due to heat dissipation.

[0021] Preferably, a cooling fan is further provided outside the furnace shell, and an air duct of the cooling fan passes through the furnace shell and the insulation layer to pass between the insulation layer and the furnace chamber, and the heating device dissipates heat through the cold air blown out by the cooling fan. The utility model optimizes the nitriding furnace, and after the optimization, the nitriding furnace uses a cooling fan to dissipate heat from the heating device, thereby preventing the heat of the heating device from not being discharged for a long time after the nitriding furnace stops working, thereby shortening the service life of the nitriding furnace, and also accelerating the cooling of the furnace chamber to prevent the temperature in the furnace chamber from being too high when the workpiece is taken out, thereby causing danger.

[0022] Preferably, a closable exhaust port is provided on the upper side of the furnace shell, and the exhaust port is connected to the heating device; the utility model optimizes the structure of the nitriding furnace, and after the optimization, the nitriding furnace is provided with a closable exhaust port, thereby improving the heat dissipation efficiency of the cooling fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0024] Figure 1 A schematic diagram showing the structure of a furnace in a tank-type pre-vacuum nitriding furnace according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the structure of a gas circulation device in a tank-type pre-vacuum nitriding furnace according to an embodiment of the utility model;

[0026] Figure 3 A schematic diagram of the front structure of a tank-type pre-vacuum nitriding furnace according to an embodiment of the utility model;

[0027] Figure 4 A schematic diagram of the back structure of a tank-type pre-vacuum nitriding furnace according to an embodiment of the utility model. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0031] Secondly, the "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that can be included in at least one implementation of the utility model. The "in one embodiment" that appears in different places in this specification does not refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] Example 1

[0033] Reference Figure 1 to Figure 4 This embodiment provides a tank-type pre-vacuum nitriding furnace, including a nitrogen adding device, a furnace shell 1 and a furnace chamber 2 arranged in the furnace shell 1. The nitrogen adding pipe of the nitrogen adding device is connected to the furnace chamber 2. A heating device 3 for heating the furnace chamber 2 is also arranged in the furnace shell 1.

[0034] The furnace 2 is also provided with a receiving chamber 6 for placing workpieces; the receiving chamber 6 is mounted in the furnace 2, and a gas circulation cavity is provided between the outer wall of the receiving chamber 6 and the inner wall of the furnace 2; a gas circulation device 4 is also provided; one end of the receiving chamber 6 is connected to the gas circulation cavity; the other end of the receiving chamber 6 is connected to the gas inlet of the gas circulation device 4; the gas outlet of the gas circulation device 4 is connected to the gas circulation cavity; a vacuum device 7 for vacuuming the cavity of the furnace 2 is also provided, and a vacuum pipe 6 of the vacuum device 7 is connected to the cavity of the furnace 2; the gas circulation device 4 is used in the furnace 2 of the nitriding furnace to drive the nitrogen to circulate in the furnace 2, so that the gas in the receiving chamber 6 is The workpiece is placed in the circulating nitrogen, which improves the uniformity and stability of the nitrogen distribution in the furnace 2. Secondly, the circulating gas can also help transfer heat to the workpiece surface more evenly, thereby ensuring that the temperature and nitrogen are evenly distributed when the workpiece is heated, making the nitriding process more uniform and efficient. Finally, the furnace 2 is also connected with a vacuum pumping device 7. Before nitriding in the nitriding furnace, the air in the furnace 2 is first extracted. Excluding oxygen or other impurity gases can reduce oxidation and pollution during the metal nitriding process, thereby improving the quality of the nitriding layer. The furnace 2 adopts a sealed muffle tank assembly formed by airtight welding of stainless steel plates to improve the sealing of the furnace 2.

[0035] The gas circulation device 4 also includes an impeller 5 and a rotating shaft 8, and the rotating shaft 8 links the driving motor of the gas circulation device 4 and the impeller 5; the furnace 2 is provided with a through hole, and the rotating shaft 8 passes through the through hole and is connected with the impeller 5; a sealed bearing 9 is provided at the matching position of the rotating shaft 8 and the through hole, and the fixed ring of the sealed bearing 9 is fixedly connected to the inner wall of the through hole, and the rotating ring of the sealed bearing 9 is interference fit with the rotating shaft 8; a sealed bearing 9 is also provided at the matching position of the rotating shaft 8 and the through hole to prevent air leakage from the furnace 2, so that the nitrogen in the furnace 2 will not leak, and the air pressure in the furnace 2 remains stable after the temperature is constant, thereby improving the nitriding quality of the workpiece.

[0036] The sealed bearing 9 is made of silicon nitride ceramic material; the utility model optimizes the sealed bearing 9, and the sealed bearing 9 made of silicon nitride ceramic material after optimization can be used in the high temperature and high pressure environment of the nitriding furnace. The fixed end of the sealed bearing 9 is connected to the through hole, and the rotating end of the sealing shaft is interference fit with the rotating shaft 8 to ensure that the connecting end will not leak. Secondly, the sealed bearing 9 ensures that no air will enter the furnace 2 of the nitriding furnace or nitrogen will leak, resulting in a decrease in the nitriding quality of the workpiece.

[0037] A contraction port is provided at one end of the accommodating chamber 6 close to the gas circulation device 4, and the contraction port is aligned with the air inlet of the gas circulation device 4; a contraction port is provided at the accommodating chamber 6 in the furnace 2 opposite to the air inlet of the gas circulation device 4, so that the air circulation device inhales air from the hole of the contraction port and exhausts air along the outer edge of the contraction port, so that the gas circulates along the inside and outside of the accommodating chamber 6, making the gas circulation trajectory clear and smooth.

[0038] The accommodating chamber 6 is provided with a support frame, one end of the support frame is fixed to the inner wall of the furnace 2, and the other end of the support frame is inserted into the accommodating chamber 6 to support the workpiece placed therein; supporting the accommodating chamber 6 with the support frame not only improves the stability of the accommodating chamber 6, but also facilitates the stable placement of the workpiece into the accommodating chamber 6.

[0039] A control valve is also provided in the vacuum tube 6 of the vacuum device 7, and the control valve controls the vacuum tube 6 to be connected; the utility model optimizes the vacuum device 7, and after the optimization, a control valve is provided in the vacuum tube 6, and the vacuum tube 6 is connected when the vacuum device 7 is in operation, and the vacuum tube 6 is closed after the vacuum is drawn, so as to prevent nitrogen leakage in the furnace 2.

[0040] The gas circulation device 4 adopts an impeller 5 made of silicon carbide ceramic material. The center of the impeller 5 is close to the end of the accommodating cavity 6 as the air inlet of the gas circulation device 4, and the circumference of the impeller 5 is the air outlet of the impeller 5. The impeller 5 made of silicon carbide ceramic has the advantages of high temperature resistance, high hardness, and wear resistance. It can operate continuously and stably in high-temperature heat treatment equipment, ensuring the continuous, stable and long-term operation of the gas circulation device 4 in the furnace 2 of the nitriding furnace.

[0041] When in use, open the sealed furnace cover of the nitriding furnace, put the workpiece on the support frame in the accommodating chamber 6, close the sealed furnace cover of the nitriding furnace, control the valve to open the vacuum tube 6, and the vacuum device 7 evacuates the furnace 2. The control valve closes the vacuum tube 6 to maintain the vacuum state of the furnace 2, and then open the nitrogen adding device to add nitrogen to the furnace 2. When the nitrogen pressure in the furnace 2 reaches a suitable pressure, stop adding nitrogen, and close the accommodating chamber 6 of the nitrogen adding device to prevent leakage, open the gas circulation device 4 and the heating device 3, so that the furnace 2 is continuously heated and the heated nitrogen is continuously flowed through the workpiece to make the workpiece evenly heated and nitrided.

[0042] Example 2

[0043] Reference Figure 3 and Figure 4 , which is the second embodiment of the utility model, and this embodiment is based on the previous embodiment.

[0044] An insulating layer of aluminum silicate wool material is also provided in the cavity of the furnace shell 1, and the heating device 3 is suspended between the insulating layer and the furnace 2; the insulating layer of aluminum silicate wool material ensures that the temperature of the furnace shell 1 will not continue to rise and cause danger, and the heating of the furnace 2 will not cause uneven heating due to heat dissipation.

[0045] A cooling fan 10 is also provided outside the furnace shell 1. The air duct of the cooling fan 10 passes through the furnace shell 1 and the insulation layer to the space between the insulation layer and the furnace 2. The heating device 3 dissipates heat through the cold air blown out by the cooling fan 10. The utility model optimizes the nitriding furnace. After the optimization, the nitriding furnace uses the cooling fan 10 to dissipate the heat of the heating device 3 to prevent the heat of the heating device 3 from not being discharged for a long time after the nitriding furnace stops working, resulting in a shortened service life of the nitriding furnace. It also accelerates the cooling of the furnace 2 to prevent the workpiece from being taken out and causing the temperature in the furnace 2 to be too high, causing danger. The air inlet of the cooling fan 10 is arranged below the furnace 2.

[0046] A closable exhaust port 11 is provided on the upper side of the furnace shell 1, and the exhaust port 11 is connected to the heating device 3; the utility model optimizes the structure of the nitriding furnace, and after the optimization, the nitriding furnace is provided with a closable exhaust port 11, which improves the heat dissipation efficiency of the cooling fan 10, and the air inlet is located below the furnace 2 and the air outlet is located above the furnace 2, so that the cold air can fully blow through the surface of the furnace 2 and the heating device 3, thereby improving the heat dissipation effect.

[0047] When in use, after the workpiece in the furnace 2 is heated and nitrided, the heating device 3 is stopped first, and the gas circulation device 4 is continuously operated to keep the cooling effect transmitted to the workpiece as soon as possible, and the exhaust port 11 and the cooling fan 10 are opened. The cold air blown by the cooling fan 10 lowers the temperature of the furnace 2 and the heating device 3. When the temperature drops to a suitable temperature, the cooling fan 10 and the exhaust port 11 are closed, the sealed furnace cover is opened, and the nitrided workpiece is taken out to complete the nitriding of the workpiece.

[0048] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and ratio of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also an equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0049] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0050] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A tank type pre-vacuum nitriding furnace, comprising a nitrogen adding device, a furnace shell and a furnace arranged in the furnace shell, wherein a nitrogen adding pipe of the nitrogen adding device is connected to the furnace, and a heating device for heating the furnace is also arranged in the furnace shell, characterized in that: The furnace is also provided with a receiving cavity for placing workpieces; The accommodating chamber is arranged in the furnace, and a gas circulation cavity is arranged between the outer wall of the accommodating chamber and the inner wall of the furnace; A gas circulation device is also provided; One end of the accommodating cavity is connected to the gas circulation cavity; the other end of the accommodating cavity is connected to the gas inlet of the gas circulation device; The gas outlet of the gas circulation device is connected to the gas circulation cavity; A vacuuming device for evacuating the furnace is also provided, and a vacuuming pipe of the vacuuming device is connected to the furnace cavity.

2. The tank type pre-vacuum nitriding furnace according to claim 1, characterized in that: The gas circulation device further comprises an impeller and a rotating shaft, wherein the rotating shaft links the driving motor of the gas circulation device and the impeller; The furnace is provided with a through hole, and the rotating shaft passes through the through hole and is connected with the impeller; A sealed bearing is arranged at the matching position between the rotating shaft and the through hole, the fixed ring of the sealed bearing is fixedly connected to the inner wall of the through hole, and the rotating ring of the sealed bearing matches the rotating shaft.

3. The tank type pre-vacuum nitriding furnace according to claim 2, characterized in that: The sealed bearing is made of silicon nitride ceramic material.

4. The tank type pre-vacuum nitriding furnace according to claim 3, characterized in that: A contraction opening is provided at one end of the accommodating cavity close to the gas circulation device, and the contraction opening is aligned with the air inlet of the gas circulation device.

5. The tank type pre-vacuum nitriding furnace according to claim 4, characterized in that: The accommodating cavity is provided with a support frame, one end of the support frame is fixed to the inner wall of the furnace, and the other end of the support frame is inserted into the accommodating cavity to support the workpiece placed therein.

6. The tank type pre-vacuum nitriding furnace according to claim 5, characterized in that: A control valve is also provided in the vacuum pipe of the vacuum pumping device, and the control valve controls the flow of the vacuum pipe.

7. The tank type pre-vacuum nitriding furnace according to claim 6, characterized in that: The gas circulation device adopts an impeller made of silicon carbide ceramic material. The center of the impeller close to one end of the accommodating cavity is the air inlet of the gas circulation device, and the circumference of the impeller is the air outlet of the impeller.

8. The tank type pre-vacuum nitriding furnace according to claim 7, characterized in that: A heat insulation layer of aluminum silicate wool material is also provided in the cavity of the furnace shell, and the heating device is suspended between the heat insulation layer and the furnace.

9. The tank type pre-vacuum nitriding furnace according to any one of claims 1 to 8, characterized in that: A cooling fan is also provided, and an air guide duct of the cooling fan passes through the furnace shell and the insulation layer to the space between the insulation layer and the furnace, and the heating device dissipates heat through the cold air blown by the cooling fan.

10. The tank type pre-vacuum nitriding furnace according to claim 9, characterized in that: A closable exhaust port is provided on the upper side of the furnace shell, and the exhaust port is connected to the heating device.

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