A cathode fin type ion nitriding furnace

Abstract

The present application provides a cathode fin type ion nitriding furnace, which is used to solve the problems of uneven heating and low thermal efficiency of ion nitriding furnaces in the prior art. It includes a support frame, a lower furnace body installed on the support frame, and an upper furnace body installed on the lower furnace body. A sealed cavity is formed between the lower furnace body and the upper furnace body. A cathode assembly for radiative and conductive heating is installed on the lower furnace body, and a heating rod is loaded on the cathode assembly. The present application uses an electric heating cathode as the main heating body, which serves as both a cathode and a heating body, rather than heating by glow heating or other auxiliary heating methods. It has good temperature controllability and high thermal efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of nitriding furnaces, and particularly relates to a cathode fin type ion nitriding furnace. Background Art

[0002] An ion nitriding furnace is a device that fills ammonia gas in a vacuum container and uses a DC electric field applied between the cathode and anode to ionize the filled ammonia gas, causing the ionized nitrogen ions to move towards the cathode. The nitrogen ions bombard the surface of the metal part to form a nitrided layer, thereby achieving surface hardening.

[0003] During the nitriding process, it is necessary to heat the workpiece. Existing ion nitriding furnaces generally use glow heating or other auxiliary heating methods for heating, resulting in low heating efficiency, poor thermal uniformity, and the occurrence of arcing phenomena during the heating process of the traditional glow heating method, resulting in low nitriding efficiency. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a cathode fin type ion nitriding furnace, which is used to solve the problems of uneven heating and low thermal efficiency of the ion nitriding furnace in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a cathode fin type ion nitriding furnace, including a support frame, a lower furnace body installed on the support frame, and an upper furnace body installed on the lower furnace body. A sealed cavity is formed between the lower furnace body and the upper furnace body. A cathode assembly for radiation and conduction heating is installed on the lower furnace body, and a heating rod is loaded on the cathode assembly.

[0006] As an optional solution, the cathode assembly includes a cathode plate seat installed at the bottom of the lower furnace body. Both ends of the cathode plate seat penetrate the bottom of the lower furnace body. The cathode plate seat and the lower furnace body are sealed and connected through a sealing sleeve. An installation hole is opened on the bottom end surface of the cathode plate seat along the vertical direction, and the heating rod is installed in the installation hole;

[0007] A plurality of cathode circular plates are arranged at equal intervals along the vertical direction on the outer part of the cathode plate seat. The cross-section of the cathode plate seat in the vertical direction is circular. The cathode circular plates and the cathode plate seat are connected through trapezoidal threads. The workpiece to be nitrided is placed on the cathode circular plates.

[0008] As an optional solution, a workpiece placing port for placing the workpiece on the cathode circular plates is opened at the top of the upper furnace body. A detachable furnace cover is installed at the workpiece placing port. Melting cast mica is installed on the bottom end surface of the furnace cover and the upper end surface of the lower furnace body. The cathode plate seat penetrates the melting cast mica on the lower furnace body;

[0009] An insulating cylinder for heat preservation and heat insulation is further arranged between the cathode assembly and the inner wall of the upper furnace body.

[0010] As an alternative, it further includes a cooling water circulation and refrigeration module and a water return tank arranged on the lower table surface of the support frame. Cooling water grooves are provided inside the bottom plate of the lower furnace body and inside the side wall of the upper furnace body. A water return pipe joint of the upper furnace body is arranged at the top of the upper furnace body, and a water inlet pipe joint of the upper furnace body is arranged at the bottom of the upper furnace body. Both the water return pipe joint and the water inlet pipe joint of the upper furnace body are communicated with the cooling water groove of the upper furnace body;

[0011] The cooling water circulation and refrigeration module is connected to the cooling water groove of the lower furnace body through a water inlet pipe. The cooling water groove of the lower furnace body is connected to the water inlet pipe joint of the upper furnace body through a furnace body connecting water pipe. The water return pipe joint of the upper furnace body is communicated with the water return tank through a water return pipe.

[0012] As an alternative, it further includes an ammonia production module, a gas storage tank and an air flow control module arranged on the lower table surface of the support frame. The ammonia production module, the gas storage tank and the air flow control module are sequentially communicated through pipelines;

[0013] An air inlet joint is installed on the outer wall of the lower furnace body. One end of the air inlet joint is communicated with the sealed cavity, and the other end of the air inlet joint is communicated with the air outlet of the air flow control module through an air inlet pipe.

[0014] As an alternative, it further includes a vacuum pumping module arranged on the lower table surface of the support frame. A vacuum joint is installed at the bottom end of the lower furnace body. One end of the vacuum joint is communicated with the sealed cavity, and the other end of the vacuum joint is communicated with the vacuum pumping module through a vacuum pipe;

[0015] A pressure sensor for monitoring air pressure is further installed on the vacuum pipe.

[0016] As an alternative, an inflation port joint is installed on the lower furnace body. One end of the inflation port joint is communicated with the sealed cavity, and the other end of the inflation port joint extends out of the bottom end surface of the lower furnace body;

[0017] A temperature sensor for monitoring temperature is further arranged on the cathode wafer. Observation windows with corresponding positions are provided on the outer walls of the upper furnace body and the heat insulation cylinder. A placing through hole corresponding to the placing port position is provided at the top end of the heat insulation cylinder.

[0018] As an alternative, an anode access port is arranged at the bottom end of the lower furnace body, and a cathode access port is arranged at the bottom end of the cathode wafer seat.

[0019] As described above, a cathode fin type ion nitriding furnace of the present invention has at least the following beneficial effects:

[0020] 1. This application uses an electrically heated cathode as the main heating body, which serves as both the cathode and the heating element, rather than using glow heating or other auxiliary heating methods. It has good temperature controllability and high thermal efficiency.

[0021] 2. Through controllable electric heating, this application has good temperature controllability. It can quickly heat the workpiece to a high temperature to volatilize the dirt on the surface. During nitriding, the flow rate of the reactive gas can be reduced, and there will be no arcing phenomenon as in the glow heating process, resulting in high nitriding efficiency.

[0022] 3. Due to the high and controllable heating temperature and the non-arcing of the cathode, this application can be used not only for nitriding common steel materials but also for metal materials such as titanium alloys that require higher nitriding temperatures, with a wide range of applications.

[0023] 4. The cathode piece base and the cathode disc in this application are connected into one body through trapezoidal threads, directly transferring the heat of the heating element to the workpiece. At the same time, the adjacent cathode discs and cathode piece bases play a role in radiation and conduction heating. The distance between the cathode discs can be adjusted through threads to adapt to the optimal distance from the workpiece, making it not easy to generate arc phenomena. At the same time, the temperature uniformity is good (less than ±5°C), and the efficiency of the glow can be fully exerted.

[0024] 5. This application uses solid urea as the gas generator for the reactive gas, which releases ammonia during heating. It does not require liquid ammonia, reducing the gas usage cost, increasing safety, and facilitating management. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It shows a schematic structural diagram of the cathode fin type ion nitriding furnace of the present invention.

[0026] Figure 2 It shows a top view of the cathode fin type ion nitriding furnace of the present invention.

[0027] In the figure: 1 - support frame; 2 - lower furnace body; 3 - upper furnace body; 4 - sealed cavity; 5 - heating rod; 6 - cathode piece base; 7 - sealing sleeve; 8 - mounting hole; 9 - cathode disc; 10 - workpiece; 11 - workpiece loading opening; 12 - furnace cover; 13 - cast mica; 14 - heat insulation cylinder; 15 - cooling water circulation and refrigeration module; 16 - water return tank; 17 - cooling water tank; 18 - upper furnace body water return pipe joint; 19 - upper furnace body water inlet pipe joint; 20 - water inlet pipe; 21 - furnace body connecting water pipe; 22 - water return pipe; 23 - ammonia production module; 24 - gas storage tank; 25 - air flow control module; 26 - air inlet joint; 27 - air inlet pipe; 28 - vacuum pumping module; 29 - vacuum joint; 30 - vacuum pipe; 31 - pressure sensor; 32 - gas filling port joint; 33 - temperature sensor; 34 - observation window; 35 - anode inlet; 36 - cathode inlet. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0029] Please refer to Figures 1 to 2 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical essential significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0030] The following various embodiments are only for illustration purposes. Combinations can be made between the various embodiments, and it is not limited to the content shown in the following single embodiment.

[0031] In this embodiment, please refer to Figure 1 and Figure 2 The present invention provides a cathode fin type ion nitriding furnace, which includes a support frame 1, a lower furnace body 2 installed on the support frame 1, and an upper furnace body 3 installed on the lower furnace body 2. A sealed cavity 4 is formed between the lower furnace body 2 and the upper furnace body 3. A cathode assembly for radiation and conduction heating is installed on the lower furnace body 2, and a heating rod 5 is loaded on the cathode assembly.

[0032] In this embodiment, the nitriding furnace further includes a nitriding furnace control power supply, and a human-machine interface is also provided on the nitriding furnace control power supply, and specific parameters can be set according to the nitriding technical requirements of different workpieces 10.

[0033] In this embodiment, the heating rod 5 is connected to the output end of the nitriding furnace control power supply. This application uses an electrically heated cathode as the heating main body, which serves as both a cathode and a heating body, rather than heating by glow heating or other auxiliary heating methods. It has good temperature controllability and high thermal efficiency. The highest temperature of the self-heating cathode is 850 - 900 °C.

[0034] Please refer to Figure 1 and Figure 2The cathode assembly includes a cathode piece base 6 installed at the bottom of the lower furnace body 2. Both ends of the cathode piece base 6 penetrate through the bottom of the lower furnace body 2. The cathode piece base 6 is hermetically connected to the lower furnace body 2 through a sealing sleeve 7. An installation hole 8 in the vertical direction is formed in the bottom end surface of the cathode piece base 6, and the heating rod 5 is installed in the installation hole 8;

[0035] A number of cathode circular plates 9 are arranged at equal intervals along the vertical direction on the outer edge of the cathode piece base 6. The cross-section of the cathode piece base 6 in the vertical direction is circular. The cathode circular plates 9 are connected to the cathode piece base 6 through trapezoidal threads. The workpiece 10 to be nitrided is placed on the cathode circular plates 9.

[0036] In this embodiment, the cathode piece base 6 is a stepped cylinder. The cathode piece base 6 and the cathode circular plates 9 are connected into one body through trapezoidal threads, directly transferring the heat of the heating element to the workpiece 10. At the same time, the adjacent cathode circular plates 9 and the cathode piece base 6 play a role in radiation and conduction heating. The distance between the cathode circular plates 9 can be adjusted through the threads to adapt to the optimal distance from the workpiece 10, not easily generating arc phenomena, having good temperature uniformity (less than ±5°C), and being able to fully exert the efficiency of glow discharge.

[0037] Please refer to Figure 1 and Figure 2 A workpiece placing port 11 for placing the workpiece 10 onto the cathode circular plates 9 is formed at the top of the upper furnace body 3. A detachable furnace cover 12 is installed at the workpiece placing port 11. Melting cast mica 13 is installed on the bottom end surface of the furnace cover 12 and the upper end surface of the lower furnace body 2. The cathode piece base 6 penetrates through the melting cast mica 13 on the lower furnace body 2;

[0038] An insulating cylinder 14 for heat preservation and heat insulation is further arranged between the cathode assembly and the inner wall of the upper furnace body 3.

[0039] In this embodiment, the insulating cylinder 14 can be connected to the inner wall at the top end of the upper furnace body 3 through a connecting piece.

[0040] Please refer to Figure 1 and Figure 2 It further includes a cooling water circulation and refrigeration module 15 and a return water tank 16 arranged on the lower surface of the support frame 1. Cooling water grooves 17 are formed in the bottom plate of the lower furnace body 2 and the side wall of the upper furnace body 3. An upper furnace body return water pipe joint 18 is arranged at the top of the upper furnace body 3, and an upper furnace body water inlet pipe joint 19 is arranged at the bottom of the upper furnace body 3. Both the upper furnace body return water pipe joint 18 and the upper furnace body water inlet pipe joint 19 are communicated with the cooling water groove 17 of the upper furnace body 3;

[0041] The cooling water circulation and refrigeration module 15 is connected to the cooling water tank 17 of the lower furnace body 2 through a water inlet pipe 20. The cooling water tank 17 of the lower furnace body 2 is connected to the water inlet joint 19 of the upper furnace body through a furnace body connecting water pipe 21. The return water joint 18 of the upper furnace body is communicated with the return water tank 16 through a return water pipe 22.

[0042] In this embodiment, the cooling water circulation and refrigeration module 15 includes a water storage tank, a refrigeration device and a water pump arranged in the water tank. The water in the return water tank flows into the water storage tank, is cooled by the refrigeration device and then pumped back into the water inlet pipe 20 through the water pump for circulation.

[0043] Please refer to Figure 1 and Figure 2 It further includes an ammonia production module 23, a gas storage tank 24 and an air flow control module 25 arranged on the lower table surface of the support frame 1. The ammonia production module 23, the gas storage tank 24 and the air flow control module 25 are sequentially communicated through pipelines;

[0044] An air inlet joint 26 is installed on the outer wall of the lower furnace body 2. One end of the air inlet joint 26 is communicated with the sealed cavity 4, and the other end of the air inlet joint 26 is communicated with the air outlet of the air flow control module 25 through an air inlet pipe 27.

[0045] In this embodiment, the ammonia production module 23 includes a urea gas production tank and a urea heater. The urea in the urea gas production tank is heated by the urea heater to produce ammonia, and the ammonia enters the gas storage tank 24 for storage. In this application, solid urea is used as the gas-emitting substance of the active gas. Ammonia is released during heating, eliminating the need for liquid ammonia, reducing the gas consumption cost, increasing safety and facilitating management.

[0046] Please refer to Figure 1 and Figure 2 It further includes a vacuum pumping module 28 arranged on the lower table surface of the support frame 1. A vacuum joint 29 is installed at the bottom end of the lower furnace body. One end of the vacuum joint 29 is communicated with the sealed cavity 4, and the other end of the vacuum joint 29 is communicated with the vacuum pumping module 28 through a vacuum pipe 30;

[0047] A pressure sensor 31 for monitoring the air pressure is further installed on the vacuum pipe 30.

[0048] Please refer to Figure 1 and Figure 2 An inflation port joint 32 is installed on the lower furnace body 2. One end of the inflation port joint 32 is communicated with the sealed cavity 4, and the other end of the inflation port joint 32 extends out of the bottom end surface of the lower furnace body 2;

[0049] A temperature sensor 33 for monitoring temperature is further provided on the cathode wafer 9. Observation windows 34 corresponding to each other in position are opened on the outer walls of the upper furnace body 3 and the heat insulation cylinder 14, and a workpiece placing through hole corresponding to the placing opening 11 in position is opened at the top end of the heat insulation cylinder 14.

[0050] In this embodiment, the gas inlet joint 32 is provided with an opening and closing valve. After the nitriding of the workpiece 10 is completed, the valve of the gas inlet joint 32 is opened to allow air to enter the sealed cavity 4; the data collected by the temperature sensor 33 is displayed through the human-machine interface of the nitriding furnace control power supply.

[0051] Please refer to Figure 1 and Figure 2 An anode inlet 35 is provided at the bottom end of the lower furnace body 2, and a cathode inlet 36 is provided at the bottom end of the cathode wafer seat 6.

[0052] In this embodiment, the nitriding furnace control power supply further includes a cathode / anode output interface, and the anode inlet 35 and the cathode inlet 36 are respectively connected to the cathode / anode output interface of the nitriding furnace control power supply.

[0053] The working process of the stethoscope with a recording function in this application is as follows:

[0054] S1: Open the furnace cover 12 to load the workpiece 10, and cover the furnace cover 12 back to the placing opening 11.

[0055] S2: Turn on the nitriding furnace control power supply and start the vacuum pumping system to pump the vacuum pressure in the furnace to below 20 Pa.

[0056] S3: Start the urea heater to heat the urea gas generator, and the generated ammonia flows into the gas storage tank 24; at the same time, start the cooling water circulation and refrigeration module 15, and turn on the output end of the nitriding furnace control power supply to supply power to the heating rod 5 to heat the workpiece 10 to the set temperature for nitriding, with automatic temperature control.

[0057] S4: Turn on the gas flow control module 25 to introduce a certain flow rate of ammonia into the furnace to keep the pressure in the furnace at 80 - 700 Pa.

[0058] S5: Turn on the output end of the nitriding furnace control power supply to output a pulsed or DC voltage of 500 - 1000 V to the anode inlet 35 and the cathode inlet 36, so that glow discharge occurs on the surface of the workpiece for nitriding treatment, and continue until the set nitriding treatment time.

[0059] S6: Turn off the output end of the nitriding furnace control power supply to stop supplying power to the heating rod 5; at the same time, turn off the gas flow control module 25 to stop supplying ammonia into the furnace, and turn off the urea heater.

[0060] S6: Turn off the output terminal of the nitriding furnace control power supply, and stop outputting anode and cathode pulses or DC voltages to the anode inlet 35 and the cathode inlet 36.

[0061] S7: Observe the in-furnace temperature display on the nitriding furnace control power supply. When the temperature drops below 100 °C, turn off the cooling water circulation and the refrigeration module 15.

[0062] S8: Open the gas inlet joint 32, and fill the furnace with air until the pressure is the same as the outside air pressure.

[0063] S9: Open the furnace cover 12 and take out the workpiece 10.

[0064] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A cathode fin type ion nitriding furnace, comprising a support frame (1), a lower furnace body (2) installed on the support frame (1), and an upper furnace body (3) installed on the lower furnace body (2). A sealed cavity (4) is formed between the lower furnace body (2) and the upper furnace body (3). It is characterized in that, A cathode assembly for radiative and conductive heating is installed on the lower furnace body (2), and a heating rod (5) is loaded on the cathode assembly; The cathode assembly includes a cathode piece base (6) installed at the bottom of the lower furnace body (2). Both ends of the cathode piece base (6) penetrate through the bottom of the lower furnace body (2). The cathode piece base (6) is hermetically connected to the lower furnace body (2) through a sealing sleeve (7). An installation hole (8) in the vertical direction is formed in the bottom end face of the cathode piece base (6), and the heating rod (5) is installed in the installation hole (8); A plurality of cathode circular plates (9) are arranged at equal intervals along the vertical direction on the outer part of the cathode piece base (6). The cross-section of the cathode piece base (6) in the vertical direction is circular. The cathode circular plates (9) are connected to the cathode piece base (6) through trapezoidal threads. The workpiece (10) to be nitrided is placed on the cathode circular plates (9); It further includes a cooling water circulation and refrigeration module (15) and a water return tank (16) arranged on the lower table surface of the support frame (1). Cooling water grooves (17) are formed in the bottom plate of the lower furnace body (2) and the side wall of the upper furnace body (3). An upper furnace body water return pipe joint (18) is arranged at the top of the upper furnace body (3), and an upper furnace body water inlet pipe joint (19) is arranged at the bottom of the upper furnace body (3). Both the upper furnace body water return pipe joint (18) and the upper furnace body water inlet pipe joint (19) are communicated with the cooling water groove (17) of the upper furnace body (3).

2. The cathode fin type ion nitriding furnace according to claim 1, characterized in that, A workpiece placing opening (11) for placing the workpiece (10) on the cathode circular plates (9) is formed at the top of the upper furnace body (3). A detachable furnace cover (12) is installed at the workpiece placing opening (11). Cast mica (13) is installed on the bottom end face of the furnace cover (12) and the upper end face of the lower furnace body (2). The cathode piece base (6) penetrates through the cast mica (13) on the lower furnace body (2); An insulating cylinder (14) for heat preservation and heat insulation is further arranged between the cathode assembly and the inner wall of the upper furnace body (3).

3. The cathode fin type ion nitriding furnace according to claim 1, characterized in that, The cooling water circulation and refrigeration module (15) is connected to the cooling water groove (17) of the lower furnace body (2) through a water inlet pipe (20). The cooling water groove (17) of the lower furnace body (2) is connected to the upper furnace body water inlet pipe joint (19) through a furnace body connecting water pipe (21). The upper furnace body water return pipe joint (18) is communicated with the water return tank (16) through a water return pipe (22).

4. A cathode fin type ion nitriding furnace according to claim 1, characterized in that, It further includes an ammonia production module (23), a gas storage tank (24) and an air flow control module (25) arranged on the lower table surface of the support frame (1). The ammonia production module (23), the gas storage tank (24) and the air flow control module (25) are sequentially communicated through pipelines; An air inlet joint (26) is installed on the outer wall of the lower furnace body (2). One end of the air inlet joint (26) is communicated with the closed cavity (4), and the other end of the air inlet joint (26) is communicated with the air outlet of the air flow control module (25) through an air inlet pipe (27).

5. A cathode fin type ion nitriding furnace according to claim 1, characterized in that, It further includes a vacuum pumping module (28) disposed on the lower table surface of the support frame (1). A vacuum connector (29) is installed at the bottom end of the lower furnace body. One end of the vacuum connector (29) is communicated with the sealed cavity (4), and the other end of the vacuum connector (29) is communicated with the vacuum pumping module (28) through a vacuum tube (30). A pressure sensor (31) for monitoring air pressure is also installed on the vacuum tube (30).

6. The cathode fin type ion nitriding furnace according to claim 2, characterized in that, An inflation port connector (32) is installed on the lower furnace body (2). One end of the inflation port connector (32) is communicated with the sealed cavity (4), and the other end of the inflation port connector (32) extends out of the bottom end surface of the lower furnace body (2). A temperature sensor (33) for monitoring temperature is also provided on the cathode wafer (9). Observation windows (34) with corresponding positions are opened on the outer walls of the upper furnace body (3) and the heat insulation cylinder (14). A workpiece placing through hole corresponding to the workpiece placing port (11) is opened at the top end of the heat insulation cylinder (14).

7. The cathode fin type ion nitriding furnace according to claim 1, wherein An anode access port (35) is provided at the bottom end of the lower furnace body (2), and a cathode access port (36) is provided at the bottom end of the cathode wafer seat (6).

Images