Metal treatment nitrogen preheating assembly, nitrogen preheating method and metal processing furnace

Abstract

The invention discloses a metal treatment nitrogen preheating assembly, which relates to the technical field of wind power part processing and comprises an outer heating cylinder and an inner heating cylinder. A nitrogen pipe is wound on an inner heating cylinder, a second electric heating pipe on the inner heating cylinder is in direct contact with the nitrogen pipe to heat the nitrogen pipe, on the basis, the second electric heating pipe further heats graphite high-temperature lubricating oil, and the graphite high-temperature lubricating oil is used for heating the part, not in contact with the second electric heating pipe, of the nitrogen pipe; therefore, the nitrogen pipe is heated in all directions, and the heating efficiency of nitrogen in the nitrogen pipe is effectively improved. Besides, the expansion medium in the expansion pipe is expanded through the graphite high-temperature lubricating oil so as to push the first electric heating pipe to be attached to the surface of the nitrogen pipe, the nitrogen in the nitrogen pipe can be directly heated by the first electric heating pipe, and the heating efficiency of the nitrogen can be further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power component processing, and in particular to a metal processing nitrogen preheating component, a nitrogen preheating method and a metal processing furnace. Background Art

[0002] Gears and ring gears are key components in wind turbine power transmission, primarily used in wind turbine transmission systems. They rely on the meshing of metal teeth for rotational transmission. Therefore, strengthening the hardness of these teeth is crucial.

[0003] At present, in order to improve the hardness of the teeth, wind turbine components with teeth will be subjected to nitrogen heat treatment. Taking the inner ring of wind turbine components as an example, the inner ring is generally made of 42CrMoA steel. After the inner ring is treated with high-temperature nitrogen at about 500°C, a layer of high-hardness and high-corrosion-resistant nitride will form on the surface of the inner ring. The hardness of the inner ring after nitriding treatment is greatly improved. Under normal circumstances, the effective hardness layer of the inner ring after nitriding treatment is 0.35-0.40mm, and the nitriding hardness is 650-750HV.

[0004] Wind turbine ring gears are relatively large, with a diameter of nearly 3 meters, requiring a large metal processing furnace. Furthermore, during nitriding, the surface hardening rate of the ring gear is 0.008mm / h. In the existing process, the ring gear is first heated to the nitriding temperature of 500°C in a saturated nitrogen atmosphere, held at that temperature for 45 hours, and then cooled. The nitriding cycle lasts for 5 days.

[0005] That is to say, under the above-mentioned nitriding treatment conditions, the nitrogen preheating efficiency must be high so that the nitrogen can be quickly distributed in the large space of the metal processing furnace after being preheated to 500°C. In the prior art, the nitrogen preheating scheme is as follows:

[0006] The nitrogen tube is made into a spiral shape and is sleeved on the outer surface of the heating tube to form a spiral sealing channel. The nitrogen in the spiral nitrogen tube is preheated by the heating tube.

[0007] However, although this preheating solution increases the contact area between the heating tube and the nitrogen tube and improves the preheating efficiency, the outer surface of the nitrogen tube is still exposed to the air, which will cause heat loss, making the preheating efficiency improvement not ideal. Summary of the Invention

[0008] One of the purposes of the present invention is to solve the problem in the prior art that when nitrogen is preheated, the outer surface of the nitrogen pipe is exposed to the air, resulting in unsatisfactory preheating efficiency.

[0009] A second object of the present invention is to provide a nitrogen preheating method.

[0010] A third object of the present invention is to provide a metal processing furnace.

[0011] To achieve one of the above purposes, the present application adopts the following technical scheme: a metal treatment nitrogen preheating assembly, comprising an outer heating cylinder and an inner heating cylinder, the outer heating cylinder is provided with a heating cavity, the heating cavity penetrates the left and right end faces of the outer heating cylinder.

[0012] The heating cavity is provided with a mounting groove on the side, and the first electric heating pipe is arranged in the mounting groove.

[0013] The left end of the inner heating cylinder is a left sealing disc, and the right end of the heating cylinder is a right sealing disc, and the second electric heating pipe is arranged between the left sealing disc and the right sealing disc.

[0014] The nitrogen pipe is wound around the inner heating cylinder, and the nitrogen pipe is in contact with the second electric heating pipe.

[0015] After the inner heating cylinder is tightly embedded in the heating cavity of the outer heating cylinder, graphite high-temperature lubricating oil is injected into the heating cavity and the mounting groove, so that the first electric heating pipe and the second electric heating pipe are immersed in the graphite high-temperature lubricating oil.

[0016] The first electric heating pipe and the second electric heating pipe are immersed in the graphite high-temperature lubricating oil, which meets the requirement that the first electric heating pipe and the second electric heating pipe must be completely immersed in liquid or metal solid, and is strictly prohibited to burn.

[0017] Further, in the embodiment of the present application, the left and right end faces of the outer heating cylinder are each provided with a first electric connection end, and the first electric connection end is electrically connected with the first electric heating pipe.

[0018] The left and right end faces of the inner heating cylinder are each provided with a second electric connection end, and the second electric connection end is electrically connected with the second electric heating pipe.

[0019] Further, in the embodiment of the present application, the left sealing disc and the right sealing disc of the inner heating cylinder are each provided with an air vent hole, and the air vent hole is communicated with the nitrogen pipe.

[0020] Further, in the embodiment of the present application, the left sealing disc is sealingly connected with the through region at the left end of the heating cavity, the through region at the right end of the heating cavity has a boss, the right sealing disc has an outwardly protruding flange, the flange is lapped on the boss to form a limiting and sealing contact.

[0021] Further, in the embodiment of the present application, the flange is fixedly connected with the boss through a screw fastener, and a sealing ring is arranged between the flange and the boss.

[0022] Further, in the embodiment of the present application, the outer heating cylinder is provided with an oil injection hole, the oil injection hole is communicated with the heating cavity, and the oil injection hole is provided with a sealing cover.

[0023] Furthermore, in an embodiment of the present invention, connecting rods are respectively installed at both ends of the first electric heating tube, and wiring terminals are provided on the sides of the connecting rods, and the first electric heating tube is electrically connected to the wiring terminals.

[0024] An expansion tube is provided in the external heating cylinder, and the expansion tube is slidably connected to the telescopic rod. An expansion medium is filled between the telescopic rod and the inner wall of the expansion tube. A channel is provided on the side of the installation groove, and the channel extends to the bottom wall of the expansion tube, so that after the graphite high-temperature lubricating oil is filled into the installation groove, it contacts the bottom wall of the expansion tube and conducts heat to the expansion medium in the expansion tube.

[0025] The outer surface of the connecting rod is covered with an insulating seat, the insulating seat is connected to the telescopic rod, and a supporting spring is provided between the insulating seat and the mounting groove.

[0026] The connection terminal at the side end of the connecting rod is connected to the first power connection terminal through an electric wire.

[0027] The beneficial effects of the present invention are:

[0028] The present invention winds the nitrogen pipe around the inner heating tube, and heats the nitrogen pipe by directly contacting the second electric heating pipe on the inner heating tube. On this basis, the second electric heating pipe also heats the graphite high-temperature lubricating oil. The part of the nitrogen pipe that does not contact the second electric heating pipe, that is, the part immersed in the graphite high-temperature lubricating oil, is heated by the graphite high-temperature lubricating oil, thereby achieving all-round heating of the nitrogen pipe and effectively improving the heating efficiency of the nitrogen in the nitrogen pipe.

[0029] In addition, the expansion medium in the expansion tube is expanded by the graphite high-temperature lubricating oil to push the first electric heating tube to fit the surface of the nitrogen tube, so that the first electric heating tube can directly heat the nitrogen in the nitrogen tube, which can further improve the heating efficiency of the nitrogen.

[0030] To achieve the second of the above objectives, the present invention adopts the following technical solution: a nitrogen preheating method, which is based on the metal treatment nitrogen preheating component described in one of the above objectives of the invention, and comprises the following steps:

[0031] Before preheating the nitrogen, wrap the nitrogen tube around the inner heating tube so that the nitrogen tube contacts the electric heating tube. Then connect the left end of the nitrogen tube to the vent hole of the left sealing disk, and then connect the right end of the nitrogen tube to the vent hole of the right sealing disk.

[0032] Then, the inner heating tube is sealed and embedded in the outer heating tube, and graphite high-temperature lubricating oil is injected into the outer heating tube, so that the first electric heating tube and the second electric heating tube are immersed in the graphite high-temperature lubricating oil.

[0033] When preheating the nitrogen, the first electric heating tube and the second electric heating tube are energized, and nitrogen is introduced into the nitrogen tube.

[0034] After the first electric heating tube and the second electric heating tube are energized, they heat the graphite high-temperature lubricating oil. At the same time, the second electric heating tube directly contacts and heats the nitrogen tube, heating the nitrogen in the nitrogen tube to a preset temperature (450℃ or 500℃ or 550℃).

[0035] The portion of the nitrogen pipe that does not contact the second electric heating pipe is immersed in graphite high-temperature lubricating oil. After the graphite high-temperature lubricating oil is heated, the portion of the nitrogen pipe that does not contact the second electric heating pipe is heated, so that the nitrogen in the nitrogen pipe is heated to the preset temperature faster.

[0036] The heated nitrogen is discharged from the nitrogen pipe.

[0037] Furthermore, in an embodiment of the present invention, in the above steps, during the heating process of the graphite high-temperature lubricating oil, the graphite high-temperature lubricating oil conducts heat to the expansion tube, causing the expansion medium (air or liquid) in the expansion tube to thermally expand, thereby pushing the telescopic rod, the insulating seat and the first electric heating tube close to the nitrogen tube, and the support spring is compressed by the insulating seat until the first electric heating tube is tightly attached to the surface of the nitrogen tube, and the nitrogen in the nitrogen tube is directly heated by the first electric heating tube.

[0038] In order to achieve the third of the above-mentioned objectives, the present invention adopts the following technical solution: a metal processing furnace, which has the metal processing nitrogen preheating component described in one of the above-mentioned objectives. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a nitrogen preheating assembly for metal processing according to an embodiment of the present invention.

[0040] Figure 2 It is a three-dimensional schematic diagram of the outer heating tube and the inner heating tube according to an embodiment of the present invention.

[0041] Figure 3 It is a three-dimensional schematic diagram of an external heating cylinder and an internal heating cylinder wrapped with a nitrogen tube according to an embodiment of the present invention.

[0042] Figure 4 for Figure 1 A partial enlarged view of point A.

[0043] 10. External heating cylinder, 11. Heating chamber, 12. Mounting slot, 13. First electrical terminal, 14. Boss, 15. Oil filling hole, 16. Electrical wire;

[0044] 20. First electric heating tube, 21. Connecting rod, 22. Terminal;

[0045] 30. Internal heating tube, 31. Right sealing disk, 32. Left sealing disk, 33. Second electric heating tube, 34. Second power terminal, 35. Vent hole, 36. Flange;

[0046] 40. Nitrogen pipe;

[0047] 50. Expansion tube, 51. Telescopic rod, 52. Expansion medium, 53. Insulation seat, 54. Support spring. DETAILED DESCRIPTION

[0048] In order to clearly and completely describe the objectives and technical solutions of the present invention and make the advantages more clearly understood, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, not all of them, and are only used to explain the embodiments of the present invention, not to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "center," "middle," "upper," "lower," "left," "right," "inner," "outer," "top," "bottom," "side," "vertical," "horizontal," and the like, indicating positions or location relationships, are based on the positions or location relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "one," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0051] For the purposes of simplicity and illustration, the principles of the embodiments are described primarily with reference to examples. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that these embodiments may not be limited to these specific details in practice. In some instances, well-known nitrogen preheating methods and structures are not described in detail to avoid unnecessarily obscuring the embodiments. Furthermore, all embodiments may be used in combination with one another.

[0052] Example 1:

[0053] It should be noted that the drawings in the specification are the contents of the specification. The structural shapes, connection relationships, coordination relationships, and positional relationships that can be obtained without any doubt in the drawings in the specification should be understood as the contents of the specification.

[0054] A metal processing nitrogen preheating component, such as Figure 1 、 Figure 2 As shown, it includes an outer heating tube 10 and an inner heating tube 30 . The outer heating tube 10 is provided with a heating cavity 11 , which passes through the left and right end surfaces of the outer heating tube 10 .

[0055] A mounting groove 12 is formed on the side of the heating chamber 11 , and a first electric heating tube 20 is disposed in the mounting groove 12 .

[0056] like Figure 2 As shown, the left end of the inner heating tube 30 is a left sealing disk 32 , the right end of the heating tube is a right sealing disk 31 , and a second electric heating tube 33 is installed between the left sealing disk 32 and the right sealing disk 31 .

[0057] like Figure 3 As shown, the nitrogen tube 40 is wound around the inner heating tube 30 , and the nitrogen tube 40 is in contact with the second electric heating tube 33 .

[0058] like Figure 1 As shown, after the inner heating tube 30 is sealed and embedded in the heating cavity 11 of the outer heating tube 10, graphite high-temperature lubricating oil is injected into the heating cavity 11 and the mounting groove 12 so that the first electric heating tube 20 and the second electric heating tube 33 are immersed in the graphite high-temperature lubricating oil.

[0059] The present invention immerses the first electric heating tube 20 and the second electric heating tube 33 in graphite high-temperature lubricating oil, meeting the requirement that the first electric heating tube 20 and the second electric heating tube 33 must be completely immersed in liquid or metal solid and empty burning is strictly prohibited.

[0060] The advantage of the present invention is that the nitrogen pipe 40 is wound around the internal heating tube 30, and the second electric heating tube 33 on the internal heating tube 30 directly contacts the nitrogen pipe 40 to heat it. On this basis, the second electric heating tube 33 also heats the graphite high-temperature lubricating oil, and the part of the nitrogen pipe 40 that does not contact the second electric heating tube 33, that is, the part immersed in the graphite high-temperature lubricating oil, is heated by the graphite high-temperature lubricating oil, thereby achieving all-round heating of the nitrogen pipe 40 and effectively improving the heating efficiency of the nitrogen in the nitrogen pipe 40.

[0061] It should be noted that the graphite high-temperature lubricant is a material disclosed in the prior art. It uses a thickener with excellent high-temperature performance, a synthetic base oil with excellent high-temperature performance, and adds a solid graphite lubricant with good high-temperature performance as an extreme pressure agent, so that the lubricant has excellent high-temperature performance, extreme pressure and anti-wear performance and oxidation stability, no dropping point at high temperature, no coking (carbon deposits), no oil separation, no loss, and the operating temperature is -10℃-600℃.

[0062] Specifically, if Figure 1 、 Figure 2 As shown, the left and right end surfaces of the external heating tube 10 are respectively provided with a first electrical terminal 13 , and the first electrical terminal 13 is electrically connected to the first electric heating tube 20 .

[0063] A second electrical connection terminal 34 is provided on each of the left and right end surfaces of the inner heating tube 30 , and the second electrical connection terminal 34 is electrically connected to the second electric heating tube 33 .

[0064] Specifically, if Figure 3 As shown, the left sealing disk 32 and the right sealing disk 31 of the inner heating cylinder 30 are each provided with a vent hole 35 , and the vent hole 35 is communicated with the nitrogen pipe 40 .

[0065] Specifically, if Figure 1 、 Figure 2 As shown, the left sealing plate 32 is sealedly connected to the through area at the left end of the heating chamber 11, the through area at the right end of the heating chamber 11 has a boss 14, and the right sealing plate 31 has an outwardly protruding flange 36, which overlaps the boss 14 to form a limiting and sealing contact.

[0066] More specifically, the flange 36 is fixedly connected to the boss 14 by screw fasteners, and a sealing ring is installed between the flange 36 and the boss 14.

[0067] Specifically, if Figure 2 As shown, the external heating cylinder 10 is provided with an oil filling hole 15 (for filling graphite high-temperature lubricating oil), the oil filling hole 15 is communicated with the heating chamber 11, and the oil filling hole 15 is provided with a sealing cover.

[0068] More specifically, if Figure 4As shown, a connecting rod 21 is installed at each end of the first electric heating tube 20, and a wiring terminal 22 is set on the side of the connecting rod 21. The first electric heating tube 20 is electrically connected to the wiring terminal 22.

[0069] An expansion tube 50 is provided in the external heating tube 10, and the expansion tube 50 is slidably connected to the telescopic rod 51. The expansion medium 52 is filled between the telescopic rod 51 and the inner tube wall of the expansion tube 50. A channel is provided on the side of the mounting groove 12, and the channel extends to the bottom wall of the expansion tube 50, so that after the graphite high-temperature lubricating oil is filled into the mounting groove 12, it contacts the bottom wall of the expansion tube 50 and conducts heat to the expansion medium 52 in the expansion tube 50.

[0070] The outer surface of the connecting rod 21 is covered with an insulating seat 53 , the insulating seat 53 is connected to the telescopic rod 51 , and a supporting spring 54 is provided between the insulating seat 53 and the mounting groove 12 .

[0071] The connection terminal 22 at the side end of the connecting rod 21 is connected to the first power terminal 13 via a wire 16. The front and rear sides of the connecting rod 21 are plate shells, which isolate and seal the area where the wire 16 is located from the installation groove 12, and a heat insulation layer is provided between the connecting rod 21 and the shell.

[0072] By expanding the expansion medium 52 in the expansion tube 50 with graphite high-temperature lubricating oil, the first electric heating tube 20 is pushed to adhere to the surface of the nitrogen tube 40, so that the first electric heating tube 20 can directly heat the nitrogen in the nitrogen tube 40, which can further improve the heating efficiency of the nitrogen.

[0073] Example 2:

[0074] A nitrogen preheating method, based on the metal treatment nitrogen preheating assembly in the above embodiment 1, comprises the following steps:

[0075] Before nitrogen preheating, the nitrogen tube 40 is wrapped around the inner heating tube 30 so that the nitrogen tube 40 contacts the electric heating tube. Then, the left end of the nitrogen tube 40 is connected to the vent 35 of the left sealing disk 32, and then the right end of the nitrogen tube 40 is connected to the vent 35 of the right sealing disk 31.

[0076] Then, the inner heating tube 30 is sealed and embedded in the outer heating tube 10 , and graphite high-temperature lubricating oil is injected into the outer heating tube 10 so that the first electric heating tube 20 and the second electric heating tube 33 are immersed in the graphite high-temperature lubricating oil.

[0077] When preheating the nitrogen, the first electric heating tube 20 and the second electric heating tube 33 are energized, and nitrogen is introduced into the nitrogen tube 40 .

[0078] After the first electric heating tube 20 and the second electric heating tube 33 are energized, they heat the graphite high-temperature lubricating oil. At the same time, the second electric heating tube 33 directly contacts and heats the nitrogen tube 40, heating the nitrogen in the nitrogen tube 40 to a preset temperature (450°C or 500°C or 550°C).

[0079] The portion of the nitrogen pipe 40 that does not contact the second electric heating pipe 33 is immersed in graphite high-temperature lubricating oil. After the graphite high-temperature lubricating oil is heated, the portion of the nitrogen pipe 40 that does not contact the second electric heating pipe 33 is heated, so that the nitrogen in the nitrogen pipe 40 is heated to the preset temperature more quickly.

[0080] The heated nitrogen gas is discharged from the nitrogen pipe 40 .

[0081] It should be noted that the temperature control of the first electric heating tube 20 and the second electric heating tube 33 is disclosed in the existing technical solution. The working principle is to obtain the real-time temperature of the nitrogen tube 40 through the temperature sensor equipped on the pipeline, and then transmit the temperature data to the control system. The system calculates the current intensity that should be output at this time based on the real-time temperature of the pipeline, combined with the pre-set values ​​such as pipeline material, insulation, material properties, material flow, and ambient temperature, thereby realizing automatic control.

[0082] The present invention immerses the first electric heating tube 20 and the second electric heating tube 33 in graphite high-temperature lubricating oil, meeting the requirement that the first electric heating tube 20 and the second electric heating tube 33 must be completely immersed in liquid or metal solid and empty burning is strictly prohibited.

[0083] The advantage of the present invention is that the nitrogen pipe 40 is wound around the internal heating tube 30, and the second electric heating tube 33 on the internal heating tube 30 directly contacts the nitrogen pipe 40 to heat it. On this basis, the second electric heating tube 33 also heats the graphite high-temperature lubricating oil, and the part of the nitrogen pipe 40 that does not contact the second electric heating tube 33, that is, the part immersed in the graphite high-temperature lubricating oil, is heated by the graphite high-temperature lubricating oil, thereby achieving all-round heating of the nitrogen pipe 40 and effectively improving the heating efficiency of the nitrogen in the nitrogen pipe 40.

[0084] Specifically, in the above steps, during the heating process of the graphite high-temperature lubricating oil, the graphite high-temperature lubricating oil conducts heat to the expansion tube 50, causing the expansion medium 52 (air or liquid) in the expansion tube 50 to expand thermally, thereby pushing the telescopic rod 51, the insulating seat 53 and the first electric heating tube 20 close to the nitrogen tube 40, and the support spring 54 is compressed by the insulating seat 53 until the first electric heating tube 20 is tightly attached to the surface of the nitrogen tube 40, and the nitrogen in the nitrogen tube 40 is directly heated by the first electric heating tube 20.

[0085] Compared to direct heating of the nitrogen in the nitrogen pipe 40 by the second electric heating pipe 33, heat conduction through the nitrogen in the nitrogen pipe 40 heated by the graphite high-temperature lubricating oil is undoubtedly slower. Therefore, by using the graphite high-temperature lubricating oil to expand the expansion medium 52 in the expansion pipe 50, the first electric heating pipe 20 is pushed against the surface of the nitrogen pipe 40. This allows the first electric heating pipe 20 to directly heat the nitrogen in the nitrogen pipe 40, further improving the heating efficiency of the nitrogen.

[0086] It should be noted that the first electric heating tube 20 initially maintains a gap with the nitrogen tube 40 in order to facilitate the smooth embedding of the inner heating tube 30 into the outer heating tube 10. Otherwise, during the embedding process, the first electric heating tube 20 is likely to generate resistance and friction with the nitrogen tube 40. On the one hand, it is easy to cause the first electric heating tube 20 to deform. On the other hand, it is easy to cause the nitrogen tube 40 wound into a loop to shift, affecting the stability of the connection between the nitrogen tube 40 and the vent 35.

[0087] In addition, it should be noted that if the expansion medium 52 is gas, calculated based on the room temperature of 20°C, the volume of the gas expanded at 50°C is 1.1 times the original volume, and the volume of the gas expanded at 200°C is 1.6 times the original volume. It is entirely possible to push the first electric heating tube 20 into contact with the nitrogen tube 40 before 200°C, so that the first electric heating tube 20, whose temperature is higher than 200°C at this time, directly heats the nitrogen in the nitrogen tube 40.

[0088] Example 3:

[0089] A metal processing furnace comprises the metal processing nitrogen preheating component of the first embodiment.

[0090] Although the above describes the illustrative specific embodiments of the present invention so that those skilled in the art can understand the present invention, the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, all inventions and creations based on the concepts of the present invention are protected.

Claims

1. A metal processing nitrogen preheating component, characterized in that: It comprises an outer heating cylinder and an inner heating cylinder, wherein the outer heating cylinder is provided with a heating cavity, and the heating cavity passes through the left and right end surfaces of the outer heating cylinder; A mounting groove is provided on the side of the heating chamber, and a first electric heating tube is provided in the mounting groove; The left end of the inner heating cylinder is a left sealing disk, the right end of the heating cylinder is a right sealing disk, and a second electric heating tube is installed between the left sealing disk and the right sealing disk; A nitrogen tube is wound around the inner heating tube, and the nitrogen tube is in contact with the second electric heating tube; After the inner heating tube is sealed and embedded in the heating cavity of the outer heating tube, graphite high-temperature lubricating oil is injected into the heating cavity and the mounting groove so that the first electric heating tube and the second electric heating tube are immersed in the graphite high-temperature lubricating oil.

2. A metal treatment nitrogen preheating assembly according to claim 1, characterized in that: The left and right end surfaces of the external heating cylinder are respectively provided with a first electrical terminal, and the first electrical terminal is electrically connected to the first electric heating tube; The left and right end surfaces of the inner heating cylinder are respectively provided with a second electrical terminal, and the second electrical terminal is electrically connected to the second electric heating tube.

3. A metal treatment nitrogen preheating assembly according to claim 1, characterized in that: The left sealing disk and the right sealing disk of the inner heating cylinder are each provided with a vent hole, and the vent hole is communicated with the nitrogen pipe.

4. A metal treatment nitrogen preheating assembly according to claim 1, characterized in that: The left sealing plate is sealedly connected to the through area at the left end of the heating chamber. The through area at the right end of the heating chamber has a boss. The right sealing plate has an outwardly protruding flange, which overlaps the boss to form a limiting and sealing contact.

5. A metal treatment nitrogen preheating assembly according to claim 4, characterized in that: The flange is fixedly connected to the boss by screw fasteners, and a sealing ring is installed between the flange and the boss.

6. A metal treatment nitrogen preheating assembly according to claim 1, characterized in that: The outer heating cylinder is provided with an oil filling hole, the oil filling hole is communicated with the heating cavity, and the oil filling hole is equipped with a sealing cover.

7. A metal treatment nitrogen preheating assembly according to claim 2, characterized in that: A connecting rod is installed at each end of the first electric heating tube, and a wiring terminal is provided on the side of the connecting rod, and the first electric heating tube is electrically connected to the wiring terminal; An expansion tube is provided in the external heating cylinder, the expansion tube is slidably connected to the telescopic rod, an expansion medium is filled between the telescopic rod and the inner wall of the expansion tube, a channel is provided on the side of the installation groove, the channel extends to the bottom wall of the expansion tube, so that after the graphite high-temperature lubricating oil is filled in the installation groove, it contacts the bottom wall of the expansion tube and conducts heat to the expansion medium in the expansion tube; The outer surface of the connecting rod is covered with an insulating seat, the insulating seat is connected to the telescopic rod, and a supporting spring is provided between the insulating seat and the mounting groove; The connection terminal at the side end of the connecting rod is connected to the first power connection terminal through an electric wire.

8. A nitrogen preheating method, characterized in that: The nitrogen preheating method is based on the metal treatment nitrogen preheating assembly according to any one of claims 1 to 7, and the nitrogen preheating method comprises the following steps: Before preheating the nitrogen, wrap the nitrogen tube around the inner heating cylinder so that the nitrogen tube contacts the electric heating tube. Then connect the left end of the nitrogen tube to the vent hole of the left sealing plate, and then connect the right end of the nitrogen tube to the vent hole of the right sealing plate. Then, the inner heating tube is sealed and embedded in the outer heating tube, and graphite high-temperature lubricating oil is injected into the outer heating tube, so that the first electric heating tube and the second electric heating tube are immersed in the graphite high-temperature lubricating oil; When preheating nitrogen, the first electric heating tube and the second electric heating tube are energized, and nitrogen is introduced into the nitrogen tube; After the first electric heating tube and the second electric heating tube are energized, they heat the graphite high-temperature lubricating oil. At the same time, the second electric heating tube directly contacts and heats the nitrogen tube, heating the nitrogen in the nitrogen tube to a preset temperature. The portion of the nitrogen pipe that is not in contact with the second electric heating pipe is immersed in graphite high-temperature lubricating oil. After the graphite high-temperature lubricating oil is heated, the portion of the nitrogen pipe that is not in contact with the second electric heating pipe is heated, so that the nitrogen in the nitrogen pipe is heated to a preset temperature more quickly; The heated nitrogen is discharged from the nitrogen pipe.

9. The nitrogen preheating method according to claim 8, characterized in that: In the above steps, during the heating process of the graphite high-temperature lubricating oil, the graphite high-temperature lubricating oil conducts heat to the expansion tube, causing the expansion medium in the expansion tube to thermally expand, thereby pushing the telescopic rod, the insulating seat and the first electric heating tube close to the nitrogen tube, and the supporting spring is compressed by the insulating seat until the first electric heating tube is tightly attached to the surface of the nitrogen tube, and the nitrogen in the nitrogen tube is directly heated by the first electric heating tube.

10. A metal processing furnace, characterized in that: The metal processing furnace comprises the metal processing nitrogen preheating component according to any one of claims 1 to 7.

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