Ultra-deep well type nitriding furnace

Abstract

The application relates to the technical field of heat treatment equipment, in particular to an ultra-deep well type nitriding furnace which comprises a furnace body, a wind guide tube and a blower, a furnace lining is arranged on the inner wall of the furnace body, a heating element is arranged on the inner wall of the furnace lining, the blower is connected with a ventilation channel arranged at the bottom of the furnace body, the furnace body is internally provided with a containing cavity, an air outlet is arranged in the containing cavity and is communicated with the ventilation channel, a furnace tube is arranged in the containing cavity, a heat transfer cylinder is arranged between the furnace tube and the inner wall of the containing cavity, a heat exchange device is arranged on the furnace lining below the wind guide tube, the bottom of the heat transfer cylinder is suspended above the heat exchange device, the top end of the heat transfer cylinder is an outwardly expanding opening, the bottom end of the heat transfer cylinder is an inwardly contracting opening, the air outlets are annularly distributed and are all located between the inner wall of the containing cavity and the outer wall of the heat transfer cylinder, and the problems of uneven heating in the furnace and slow cooling of workpieces are solved.

Description

Technical Field

[0001] This application relates to the field of heat treatment equipment technology, and in particular to an ultra-deep well nitriding furnace. Background Technology

[0002] Nitriding furnaces are mainly used for surface strengthening treatments such as nitriding, multi-element co-diffusion, low-temperature austenitic nitrocarburizing, oxynitrogen co-diffusion, steam oxidation, and low-vacuum tempering (or aging) on ​​steel parts, molds, measuring tools, and other hardware products. The nitriding furnace operation involves placing the workpiece inside, closing the furnace lid, circulating cooling water through the lid, venting the furnace with protective gases such as nitrogen, and introducing nitriding raw materials such as ammonia or ethanol. The process is maintained at the nitriding temperature for 3–90 hours. Nitriding or nitrocarburizing is achieved by utilizing the decomposition of NH3 to provide nitrogen atoms or simultaneously utilizing carbon-containing materials to provide carbon elements, resulting in a strengthened surface layer on the workpiece and achieving high hardness, high wear resistance, and fatigue resistance.

[0003] Pit-type nitriding furnaces typically use multiple heaters to heat the furnace chamber, which can easily lead to uneven heating. In addition, to improve equipment utilization, the workpiece should be cooled from the process temperature of approximately 560°C to a temperature less than 100°C for unloading as quickly as possible. Conventional pit-type nitriding furnaces are equipped with a cooling blower to blow air out of the furnace chamber, so that some heat is discharged through the exhaust valve. However, since the workpiece is inside the furnace chamber, the air blown by the blower is isolated from the workpiece, and the two are in an indirect heat exchange process, making it difficult to achieve rapid cooling of the workpiece. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide an ultra-deep well nitriding furnace, which solves the problems of uneven heating inside the furnace and the inability to cool the workpiece quickly.

[0005] To solve the above problems, the following technical solutions are provided:

[0006] This solution is an ultra-deep well nitriding furnace, comprising a furnace body, an air guide duct, and a blower. A furnace lining is installed on the inner wall of the furnace body, and heating elements are installed on the inner wall of the furnace lining. The blower is connected to a ventilation duct at the bottom of the furnace body. The furnace body has an internal cavity with an air outlet connected to the ventilation duct. A furnace chamber is located within the cavity, and a cooling air duct is formed between the furnace chamber and the inner wall of the cavity. A heat transfer cylinder is located within the cooling air duct and is fitted around the outside of the furnace chamber. A heat exchange device is installed on the furnace lining below the air guide duct, with the bottom of the heat transfer cylinder suspended above the heat exchange device. The top of the heat transfer cylinder is an outwardly expanding opening, and the bottom is an inwardly contracting opening. The air outlets are distributed in a ring, and all outlets are located between the inner wall of the cavity and the outer wall of the heat transfer cylinder.

[0007] By adopting the above technical solution: a heat transfer cylinder is installed in the cooling air duct of the furnace body. On the one hand, the heat transfer cylinder can easily and evenly distribute the heat generated by the heating element and transfer this heat evenly to the entire furnace shell, avoiding uneven heating in multiple places in the furnace shell. On the other hand, the heat transfer cylinder adopts a structure with an open upper end and an open lower end. In order to obtain good air guiding function during the cooling process, the heat transfer cylinder gathers the cooling air from the outside to the inside to the heat exchange device for heat exchange, thereby rapidly reducing the temperature inside the furnace body.

[0008] The bottom end of the heat transfer cylinder is fixedly connected to the furnace lining via support legs.

[0009] By adopting the above technical solution, the heat transfer cylinder is fixedly installed on the furnace substrate by its bottom support legs.

[0010] The inner wall of the furnace is provided with a support base, and the outer surface of the air guide tube is provided with an inverted top block. The inverted top block abuts against the support base so that the air guide tube is suspended inside the furnace. An air guide channel is also left between the support base and the inverted top block. The inner wall of the furnace is also provided with a positioning component for circumferential positioning of the air guide tube.

[0011] By adopting the above technical solution, the air guide duct can be suspended in the furnace by the anti-top block and the support seat. The circumferential position of the air guide duct in the furnace is also determined by the positioning component, which ensures the stability of the air guide duct placement. The air guide duct is connected to the support seat on the inner wall of the furnace by the anti-top block, so that the air guide duct is suspended in the furnace. Compared with the existing pit-type nitriding furnace, the radial area occupied by the support structure of the air guide duct in this solution is smaller in the furnace, which greatly improves the flow performance of the atmosphere gas.

[0012] The support bases are distributed in a ring at intervals on the inner wall of the furnace, the anti-top blocks are distributed in a ring at intervals on the outer surface of the air guide, and the outer side of the anti-top blocks is fixedly connected with a retaining ring. The top of each support base is provided with a limiting groove, and the bottom of the anti-top blocks and the retaining rings abut against the limiting grooves.

[0013] By adopting the above technical solution: the outer ring of the air guide tube is concentrically installed with a retaining ring through the anti-top block to ensure that the air guide tube has sufficient stability when placed on the fixed block, and the support base is opened with a limiting groove to ensure that the air guide tube can be located in the center of the furnace, thereby ensuring the uniformity of gas flow around the air guide tube.

[0014] The positioning assembly includes two positioning plates fixedly connected to the inner wall of the furnace liner. The distance between the two positioning plates is slightly greater than the thickness of the anti-top block, and the space between the two positioning plates is used for the insertion of the anti-top block to circumferentially position the air guide tube.

[0015] By adopting the above technical solution: setting two positioning plates and inserting the anti-top block between the two positioning plates, the circumferential direction of the air guide can be limited, thereby further improving the stability of the air guide.

[0016] The air guide channel is formed by the inner wall of the furnace shell, the outer wall of the air guide tube, and two adjacent mutually cooperating support seats and anti-top blocks.

[0017] By adopting the above technical solution: after the furnace is installed, air guide channels are opened between adjacent fixed blocks and anti-top blocks to reduce the occupation of the radial area of ​​the furnace and improve the flow performance of atmospheric gas through the air guide channels.

[0018] A first air outlet pipe is vertically arranged on the inner wall of the air guide duct, and a second air outlet pipe is vertically arranged on the inner wall of the furnace. The first air outlet pipe has multiple first air outlets, and the bottom end of the second air outlet pipe has a second air outlet. The first air outlets are evenly distributed according to the length of the air guide duct, and the second air outlets are close to the bottom of the furnace. The first air outlet and the second air outlet are respectively connected to annular first air guide pipes and second air guide pipes. The first air guide pipe is fixedly connected to the inner wall of the air guide duct, and the second air guide pipe is fixedly connected to the bottom wall of the furnace. Both the first air guide pipe and the second air guide pipe have air outlet holes.

[0019] By adopting the above technical solution: a first air outlet pipe is provided inside the air guide duct, and multiple first air outlets are provided on the first air outlet pipe. The first air outlets are evenly distributed along the air guide duct to ensure that the atmospheric gas can enter the muffle uniformly and quickly, thereby ensuring product quality. The first air guide pipe and the second air guide pipe are both designed as rings, which facilitates the placement of workpieces and ensures that the gas can be evenly dispersed in the radial plane, further improving the uniformity of gas filling into the furnace.

[0020] The air outlets are evenly distributed on the inner sides of the first and second air guide pipes.

[0021] By adopting the above technical solution, the uniformity of the atmosphere inside the air duct can be further improved.

[0022] A furnace cover is installed at the top of the furnace body, and a fan is fixedly connected to the upper end of the furnace cover. The fan blades are connected after passing through the furnace cover. The heating element is a resistance band. A temperature measuring tube is provided on the furnace body, and one end of the temperature measuring tube passes through the furnace lining and extends into the cooling air duct.

[0023] By adopting the above technical solution: the fan drives the fan blades to rotate, which generates negative pressure in the air guide tube; the heating element is a resistance strip, and the resistance strip is fixed to the inner wall of the furnace lining by a ceramic screw. The structure is simple and easy to install, which enhances the heat exchange in the furnace and improves the thermal efficiency of the nitriding furnace; the temperature measuring tube is used to sense the actual temperature in the furnace, so as to achieve the requirement of precise control of the furnace temperature.

[0024] The above approach has the following advantages:

[0025] 1. In this application, a heat transfer cylinder is installed in the cooling air duct of the furnace body. This heat transfer cylinder facilitates the even distribution of heat generated by the heating elements and transfers this heat uniformly throughout the furnace chamber, preventing uneven heating in multiple areas. Furthermore, the heat transfer cylinder employs a structure with an open upper end and an inward-open lower end. To achieve good airflow during cooling, the heat transfer cylinder concentrates the cooling air from the outside to the inside, directing it to the heat exchange device for heat exchange, thereby rapidly reducing the temperature inside the furnace body.

[0026] 2. In this application, the air guide duct can be suspended inside the furnace by abutting against the support seat via the anti-top block. The circumferential position of the air guide duct in the furnace is also determined by the positioning component, which ensures the stability of the air guide duct placement. The air guide duct is connected to the support seat on the inner wall of the furnace via the anti-top block, so that the air guide duct is suspended inside the furnace. Compared with the existing pit-type nitriding furnace, the radial area occupied by the support structure of the air guide duct in this solution is smaller in the furnace, which greatly improves the flow performance of the atmosphere gas. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the main structure of the ultra-deep well nitriding furnace of this application;

[0028] Figure 2 This is a partial structural schematic diagram of the ultra-deep well nitriding furnace of this application;

[0029] Figure 3 This is a top view of the ultra-deep well nitriding furnace of this application.

[0030] Figure 4 This is a schematic diagram of the structure of the furnace lining of the ultra-deep well nitriding furnace of this application.

[0031] Reference numerals in the attached drawings: 1. Furnace body; 2. Air duct; 3. Blower; 4. Furnace lining; 5. Heating element; 6. Ventilation duct; 7. Air outlet; 8. Furnace shell; 9. Cooling air duct; 10. Heat transfer tube; 11. Heat exchange device; 12. Outer opening; 13. Inner opening; 14. Support leg; 15. Support base; 16. Anti-top block; 17. Air duct; 18. Baffle ring; 19. Limiting groove; 20. Positioning plate; 22. First air outlet pipe; 23. Second air outlet pipe; 24. First air guide pipe; 25. Second air guide pipe. Detailed Implementation

[0032] The present invention will be described below with reference to the accompanying drawings and embodiments.

[0033] Example

[0034] This solution is an ultra-deep well nitriding furnace, such as Figure 1As shown, it includes a furnace body 1, an air duct 2, and a blower 3. A furnace lining 4 is installed on the inner wall of the furnace body 1, and a heating element 5 is installed on the inner wall of the furnace lining 4. The blower 3 is connected to a ventilation duct 6 at the bottom of the furnace body 1. The furnace body 1 has an internal cavity with an air outlet 7 connected to the ventilation duct 6. A furnace chamber 8 is located within the cavity, and a cooling air duct 9 is formed between the furnace chamber 8 and the inner wall of the cavity. A heat transfer cylinder 10 is installed in the cooling air duct 9, and the heat transfer cylinder 10 is fitted around the outside of the furnace chamber 8. A heat exchange device 11 is installed on the furnace lining 4 below the air duct 2, and the bottom of the heat transfer cylinder 10 is suspended above the heat exchange device 11. The top of the heat transfer cylinder 10... The heat transfer cylinder 10 has an outwardly expanding opening 12 at one end and an inwardly contracting opening 13 at the bottom. The air outlets 7 are distributed in a ring and are all located between the inner wall of the cavity and the outer wall of the heat transfer cylinder 10. Since the heat transfer cylinder 10 is installed in the cooling air duct 9 of the furnace body 1, the heat transfer cylinder 10 can easily and evenly disperse the heat generated by the heating element 5 and evenly transfer this heat to the entire furnace 8, avoiding uneven heating in multiple places in the furnace 8. On the other hand, the heat transfer cylinder 10 adopts a structure with an outwardly expanding upper end and an inwardly expanding lower end. In order to obtain a good air guiding function during the cooling process, the heat transfer cylinder 10 gathers the cooling air from the outside to the inside to the heat exchange device 11 for heat exchange, thereby quickly reducing the temperature inside the furnace body 1.

[0035] When cooling the workpiece, the heating unit stops heating, and the blower 3 sends cooling air through the cooling duct 9 and into the cooling duct 7. Since the air outlet 7 is located on the outside of the heat transfer cylinder 10 and is in contact with the furnace lining 4, the cooling air absorbs the temperature of the furnace lining 4. Then, the cooling air rises from the outer wall of the heat transfer cylinder 10 to the outer opening 12. Since the outer opening 12 is set at the top of the heat transfer cylinder 10, it is easy for the cooling air to rise along the outer wall of the heat transfer cylinder 10 and enter the inner wall of the heat transfer cylinder 10, avoiding the backflow of cooling air. The cooling air then passes through the air guide duct 2 and carries away the heat to the top of the heat exchange device 11. The inner opening 13 at the bottom of the heat transfer cylinder 10 facilitates the cooling air that carries away the heat from the air guide duct 2 to fully exchange heat with the heat exchange device 11. The cooled gas then enters the outside of the heat transfer cylinder 10. This cycle causes the temperature inside the furnace to drop rapidly, thereby reducing the surface temperature of the workpiece.

[0036] Furthermore, the bottom end of the heat transfer cylinder 10 is fixedly connected to the furnace lining 4 via a support leg 14. The heat transfer cylinder 10 is fixedly installed at the bottom of the furnace lining 4 via the support leg 14 at its bottom.

[0037] Furthermore, such as Figure 2 and Figure 3As shown, a support base 15 is provided on the inner wall of the furnace chamber 8, and an anti-top block 16 is provided on the outer surface of the air guide duct 2. The anti-top block 16 abuts against the support base 15, suspending the air guide duct 2 inside the furnace chamber 8. An air guide channel 17 is also provided between the support base 15 and the anti-top block 16. A positioning component for circumferential positioning of the air guide duct 2 is also provided on the inner wall of the furnace chamber 8. The air guide duct 2 can be suspended inside the furnace chamber 8 by abutting against the support base 15 with the anti-top block 16. The circumferential position of the air guide duct 2 in the furnace chamber 8 is also determined by the positioning component, ensuring the stability of the placement of the air guide duct 2. The air guide duct 2 is connected to the support base 15 on the inner wall of the furnace chamber 8 through the anti-top block 16, so that the air guide duct 2 is suspended inside the furnace chamber 8. Compared with the existing pit-type nitriding furnace, the radial area occupied by the support structure of the air guide duct 2 in this solution is smaller in the furnace chamber 8, which greatly improves the flow performance of the atmosphere gas.

[0038] like Figure 2 As shown, the support bases 15 are arranged in a ring at intervals on the inner wall of the furnace liner 8, and the anti-top blocks 16 are arranged in a ring at intervals on the outer surface of the air guide duct 2. A retaining ring 18 is fixedly connected to the outer side of each anti-top block 16. Limiting grooves 19 are formed on the top of each support base 15, and the bottoms of both the anti-top blocks 16 and the retaining rings 18 abut against the limiting grooves 19. The outer ring of the air guide duct 2 is concentrically mounted with retaining rings 18 via the anti-top blocks 16, ensuring sufficient stability when the air guide duct 2 is placed on the fixed blocks. The limiting grooves 19 on the support bases 15 ensure that the air guide duct 2 is centered in the furnace liner 8, thereby ensuring uniform gas flow around the air guide duct 2.

[0039] Furthermore, for example Figure 3 As shown, the positioning assembly includes two positioning plates 20 fixedly connected to the inner wall of the furnace liner 8. The distance between the two positioning plates 20 is slightly greater than the thickness of the anti-top block 16, and the space between the two positioning plates 20 is used for the insertion of the anti-top block 16 to circumferentially position the air guide duct 2. By setting two positioning plates 20 and inserting the anti-top block 16 between them, the circumferential direction of the air guide duct 2 can be limited, further improving the stability of the air guide duct 2.

[0040] Furthermore, the air guide channel 17 is formed by the inner wall of the furnace liner 8, the outer wall of the air guide tube 2, and two adjacent cooperating support seats 15 and anti-top blocks 16. After the furnace liner 8 is installed, air guide channels 17 are provided between adjacent fixed blocks and anti-top blocks 16, reducing the occupation of the radial area of ​​the furnace liner 8 and improving the flow performance of atmospheric gas through the air guide channels 17.

[0041] like Figure 4As shown, in this embodiment, a first air outlet pipe 22 is vertically arranged on the inner wall of the air guide duct 2, and a second air outlet pipe 23 is vertically arranged on the inner wall of the furnace liner 8. The first air outlet pipe 22 is provided with multiple first air outlets, and the bottom end of the second air outlet pipe 23 is provided with a second air outlet. The first air outlets are evenly distributed according to the length of the air guide duct 2, and the second air outlets are close to the bottom of the furnace liner 8. The first air outlet and the second air outlet are respectively connected to annular first air guide pipes 24 and second air guide pipes 25. The first air guide pipe 24 is fixedly connected to the inner wall of the air guide duct 2, and the second air guide pipe 25 is fixedly connected to the bottom wall of the furnace liner 8. Air outlet holes are opened on both the first air guide pipe 24 and the second air guide pipe 25. Since the air duct 2 is equipped with a first air outlet pipe 22, and the first air outlet pipe 22 is equipped with multiple first air outlets, the first air outlets are evenly distributed along the air duct 2, ensuring that the atmospheric gas can enter the muffle uniformly and quickly, thereby ensuring product quality. The first air duct 24 and the second air duct 25 are both designed as rings, which facilitates the placement of workpieces and ensures that the gas can be evenly dispersed in the radial plane, further improving the uniformity of gas filling into the furnace body 1.

[0042] Furthermore, the air outlets are evenly distributed inside the first air guide pipe 24 and the second air guide pipe 25 to ensure the uniformity of the atmosphere entering the air guide duct 2.

[0043] Furthermore, a furnace cover is installed at the top of the furnace body 1, and a fan is fixedly connected to the upper end of the furnace cover. The fan blades are connected to the furnace cover. The heating element 5 is a resistance band, and a temperature measuring tube is installed on the furnace body 1. One end of the temperature measuring tube penetrates the furnace lining 4 and extends into the cooling air duct 9. During operation, the fan drives the fan blades to rotate, creating a negative pressure inside the air duct 2. The heating element 5 is a resistance band, which is fixed to the inner wall of the furnace lining 4 by ceramic screws. This design is simple, easy to install, enhances heat exchange within the furnace, and improves the thermal efficiency of the nitriding furnace. The temperature measuring tube is used to sense the actual temperature inside the furnace, achieving precise temperature control.

[0044] The present invention has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present invention. Furthermore, those skilled in the art can make various modifications and variations to the present invention based on the spirit and principles of the present invention, and these modifications and variations are also within the scope of the present invention.

Claims

1. An ultra-deep well nitriding furnace, comprising a furnace body (1), an air duct (2), and a blower (3), wherein a furnace lining (4) is installed on the inner wall of the furnace body (1), a heating element (5) is installed on the inner wall of the furnace lining (4), the blower (3) is connected to a ventilation duct (6) opened at the bottom of the furnace body (1), the furnace body (1) has an internal cavity, an air outlet (7) connected to the ventilation duct (6) is provided in the cavity, a furnace chamber (8) is provided in the cavity, and a cooling air duct (9) is formed between the furnace chamber (8) and the inner wall of the cavity, characterized in that, The cooling air duct (9) is provided with a heat transfer cylinder (10), which is sleeved on the outside of the furnace shell (8). A heat exchange device (11) is installed on the furnace lining (4) below the air guide duct (2). The bottom of the heat transfer cylinder (10) is suspended above the heat exchange device (11). The top of the heat transfer cylinder (10) is an external opening (12), and the bottom of the heat transfer cylinder (10) is an internal opening (13). The air outlets (7) are distributed in a ring and are all located between the inner wall of the accommodating cavity and the outer wall of the heat transfer cylinder (10). When cooling the workpiece, the heating unit stops heating, and the blower (3) sends cooling air through the cooling duct (9) and into the cooling duct (9) through the air outlet (7). Since the air outlet (7) is located on the outside of the heat transfer cylinder (10) and in contact with the furnace lining (4), the cooling air draws away the temperature of the furnace lining (4). Next, the cooling air rises from the outer wall of the heat transfer cylinder (10) to the outer opening (12). Since the outer opening (12) is set at the top of the heat transfer cylinder (10), it is easy for the cooling air to flow along the heat transfer cylinder (10). The air flows upward from the outer wall of the heat transfer cylinder (10) into the inner wall of the heat transfer cylinder (10), avoiding backflow of cooling air. The cooling air then passes through the air guide (2) and carries away heat to the top of the heat exchange device (11). The inner opening (13) at the lower end of the heat transfer cylinder (10) facilitates the cooling air carrying away heat from the air guide (2) to fully exchange heat with the heat exchange device (11). The cooled gas then enters the outer side of the heat transfer cylinder (10). This cycle causes the temperature inside the furnace to drop rapidly, thereby reducing the surface temperature of the workpiece.

2. The ultra-deep well nitriding furnace as described in claim 1, characterized in that, The bottom end of the heat transfer cylinder (10) is fixedly connected to the furnace lining (4) by a support foot (14).

3. An ultra-deep well nitriding furnace as described in claim 1 or 2, characterized in that, The inner wall of the furnace (8) is provided with a support seat (15), and the outer surface of the air guide tube (2) is provided with an anti-top block (16). The anti-top block (16) abuts against the support seat (15) so that the air guide tube (2) is suspended inside the furnace (8). There is also an air guide channel (17) between the support seat (15) and the anti-top block (16). The inner wall of the furnace (8) is also provided with a positioning component for circumferential positioning of the air guide tube (2).

4. The ultra-deep well nitriding furnace as described in claim 3, characterized in that, The support base (15) is distributed in a ring at intervals on the inner wall of the furnace (8), the anti-top block (16) is distributed in a ring at intervals on the outer surface of the air guide (2), and a retaining ring (18) is fixedly connected to the outer side of the anti-top block (16). The top of the support base (15) is provided with a limiting groove (19), and the bottom of the anti-top block (16) and the retaining ring (18) abut against the limiting groove (19).

5. The ultra-deep well nitriding furnace as described in claim 3, characterized in that, The positioning assembly includes two positioning plates (20) fixedly connected to the inner wall of the furnace (8). The distance between the two positioning plates (20) is slightly greater than the thickness of the anti-top block (16), and the space between the two positioning plates (20) is used for the insertion of the anti-top block (16) to circumferentially position the air guide tube (2).

6. The ultra-deep well nitriding furnace as described in claim 4, characterized in that, The air guide channel (17) is formed by the inner wall of the furnace shell (8), the outer wall of the air guide tube (2), and two adjacent mutually cooperating support seats (15) and anti-top block (16).

7. The ultra-deep well nitriding furnace as described in claim 1, characterized in that, The inner wall of the air guide tube (2) is vertically provided with a first air outlet pipe (22), and the inner wall of the furnace (8) is vertically provided with a second air outlet pipe (23). The first air outlet pipe (22) is provided with multiple first air outlets, and the bottom end of the second air outlet pipe (23) is provided with a second air outlet. The first air outlets are evenly distributed according to the length of the air guide tube (2), and the second air outlets are close to the bottom of the furnace (8). The first air outlet and the second air outlet are respectively connected to annular first air guide pipe (24) and second air guide pipe (25). The first air guide pipe (24) is fixedly connected to the inner wall of the air guide tube (2), and the second air guide pipe (25) is fixedly connected to the bottom wall of the furnace (8). The first air guide pipe (24) and the second air guide pipe (25) are both provided with air outlet holes.

8. The ultra-deep well nitriding furnace as described in claim 7, characterized in that, The air outlets are evenly distributed on the inner sides of the first air guide tube (24) and the second air guide tube (25).

9. The ultra-deep well nitriding furnace as described in claim 1, characterized in that, The furnace body (1) is equipped with a furnace cover at the top. A fan is fixedly connected to the upper end of the furnace cover. The fan blades are connected after passing through the furnace cover. The heating element (5) is a resistance band. A temperature measuring tube is provided on the furnace body (1). One end of the temperature measuring tube passes through the furnace lining (4) and extends into the cooling air duct (9).

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