Large workpiece inner hole nitriding treatment device

Abstract

The utility model discloses a large-scale workpiece inner bore nitriding treatment device, which comprises a trolley type resistance furnace and a workpiece to be processed in a furnace chamber of the trolley type resistance furnace, the workpiece is hollow inside and has two open ends, the two open ends of the workpiece are respectively and hermetically connected with cover plates, one cover plate is provided with a gas inlet joint, and the other cover plate is provided with a gas outlet joint. The other cover plate is provided with an air outlet joint; the gas inlet connector is connected with a gas inlet pipeline, the end, away from the gas inlet connector, of the gas inlet pipeline is connected with an ammonia gas supply device, the gas outlet connector is connected with a gas outlet pipeline, the end, away from the gas outlet connector, of the gas outlet pipeline is connected with a tail gas treatment device, and the ammonia gas supply device and the tail gas treatment device are both located outside the trolley type resistance furnace. The cover plates are directly and additionally arranged at the two ends of the workpiece, the workpiece is modified into the simple muffle tank, ammonia gas is introduced into the workpiece, the workpiece can be nitrided and hardened only by putting the workpiece into a common large trolley type resistance furnace, and the single nitrided inner cavity is low in investment cost.

Description

Technical Field

[0001] The utility model relates to the technical field of metal surface treatment equipment, in particular to a nitriding treatment device for inner holes of large workpieces. Background Art

[0002] In the process of nitriding metal workpieces, a gas nitriding furnace is generally used. Its working principle is to form a hard, wear-resistant and corrosion-resistant nitrided layer on the metal surface through a specific atmosphere, thereby greatly improving the performance and service life of the metal material. This process is based on the nitriding reaction. The metal workpiece is placed in a mixed gas environment containing ammonia. Under a certain temperature and pressure, the ammonia decomposition gas reacts chemically with the elements on the metal surface to form nitrides. The specific process includes: (1) Ammonia decomposition: At a certain temperature (usually 500-600℃), ammonia decomposes into active nitrogen atoms; (2) Absorption process: The steel surface absorbs nitrogen atoms to form a saturated solid solution of nitrogen in iron, and then forms nitrides; (3) Diffusion process: Nitrogen atoms diffuse from the surface saturated layer to the deep inner layer of the steel, forming a nitrided layer of a certain depth.

[0003] At present, for some large-sized workpieces with inner holes, especially customized special workpiece products, when the inner holes need to be hardened or all surfaces need to be hardened, if conventional surface treatment methods (brush plating, high-frequency quenching, laser quenching, flame quenching, etc.) are used, it will be difficult to operate on the inner holes or in the inner cavity due to space and bench limitations; if a muffle pit furnace is used for treatment, the conventional muffle pit furnace is not large enough to be directly placed in it, and a corresponding large-sized muffle pit furnace needs to be developed, which will lead to increased costs and longer construction and production cycles.

[0004] Therefore, there is an urgent need for a nitriding treatment device that can nitride the inner cavity of a large workpiece conveniently and at low cost. Utility Model Content

[0005] The purpose of the utility model is to provide a large workpiece inner hole nitriding treatment device, which can be used to transform existing conventional equipment with low-cost investment, thereby realizing simple and rapid nitriding treatment of special workpieces, and well solving the problems mentioned in the above background technology.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A device for nitriding the inner holes of a large workpiece comprises a trolley-type resistance furnace and a workpiece to be processed located in the furnace chamber of the trolley-type resistance furnace, wherein the workpiece is hollow inside and open at both ends, and the two open ends of the workpiece are respectively sealed and connected with cover plates, wherein one cover plate is provided with an air inlet joint, and the other cover plate is provided with an air outlet joint; the air inlet joint is connected to an air inlet pipe, and the end of the air inlet pipe away from the air inlet joint is connected to an ammonia supply device, and the air outlet joint is connected to an air outlet pipe, and the end of the air outlet pipe away from the air outlet joint is connected to an exhaust gas treatment device, and the ammonia supply device and the exhaust gas treatment device are both located outside the trolley-type resistance furnace.

[0008] Furthermore, the exhaust gas treatment device includes an exhaust gas discharge pipe and a pressure regulating valve. The pressure regulating valve is installed at one end of the exhaust pipe away from the exhaust joint, and the end of the exhaust gas discharge pipe away from the combustion port is connected to the pressure regulating valve.

[0009] Furthermore, a detection pipeline is connected between the pressure regulating valve and the gas outlet pipeline, and the detection pipeline is sequentially connected to a pressure gauge, a first valve, a hydrogen probe and a second valve.

[0010] Furthermore, the exhaust gas discharge pipe is a metal pipe, and a plurality of heat dissipation fins are provided on the outer peripheral wall of the exhaust gas discharge pipe.

[0011] Furthermore, the heat dissipation fins are distributed at equal intervals along the exhaust pipe.

[0012] Furthermore, the ammonia supply device includes an ammonia cylinder, an air intake valve and an ammonia input pipe. The air intake valve is installed at one end of the air intake pipe away from the air intake joint, and both ends of the ammonia input pipe are respectively connected to the air intake valve and the ammonia cylinder.

[0013] Furthermore, the air inlet pipe and the air outlet pipe are both stainless steel pipes.

[0014] Furthermore, the trolley-type resistance furnace includes a furnace body, a horizontally displaceable trolley and a liftable furnace door device, the upper surface of the trolley is provided with a plurality of pillow blocks for supporting workpieces and at least one pad located between the furnace door device and the trolley, and a gap is formed between the furnace door device and the trolley for the air inlet duct and the air outlet duct to pass through.

[0015] Furthermore, the spacer block is a refractory brick.

[0016] Furthermore, the workpiece is a box-shaped workpiece or a tube-shaped workpiece.

[0017] Compared with the prior art, the present invention provides a large workpiece inner hole nitriding treatment device, which has the following beneficial effects:

[0018] This utility model utilizes the inherent structural characteristics of the workpiece, directly adding cover plates to both ends of the workpiece, converting it into a simple muffle tank. By introducing ammonia gas into the interior of the workpiece, the workpiece can be placed in a common large-scale trolley-type resistance furnace to achieve nitriding and hardening of the workpiece cavity; the outer surface of the workpiece can be hardened by other conventional surface local quenching methods (such as handheld high-frequency quenching, laser quenching, etc.) or surface treatment methods such as brush plating. The use of this utility model has a low investment cost per unit of nitriding inner cavity, and can use conventional equipment to process special workpieces. It is suitable for nitriding and hardening the inner holes of large parts, especially customized large-sized workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 It is a structural diagram of the utility model;

[0021] Figure 2 A schematic diagram of sealing and installing cover plates at both ends of a workpiece to be processed;

[0022] Figure 3 This is a schematic diagram of the connection between the exhaust gas treatment device, the detection pipeline and the exhaust pipeline;

[0023] Figure 4 This is a structural diagram of a trolley-type resistance furnace.

[0024] Figure numerals: 1. Trolley-type resistance furnace; 11. Furnace body; 12. Trolley; 13. Furnace door device; 14. Furnace cavity; 15. Pillow block; 16. Pad block; 17. Gap; 2. Cover plate; 3. Air inlet connector; 4. Air outlet connector; 5. Air inlet pipe; 6. Ammonia supply device; 61. Ammonia bottle; 62. Air inlet valve; 63. Ammonia input pipe; 7. Air outlet pipe; 8. Exhaust gas treatment device; 81. Exhaust gas discharge pipe; 82. Pressure regulating valve; 83. Heat dissipation fins; 9. Detection pipeline; 91. Pressure gauge; 92. First valve; 93. Hydrogen probe; 94. Second valve; 10. Workpiece. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions of the present invention through detailed embodiments and in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on 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.

[0026] Please refer to Figures 1 to 4 The present embodiment provides a large workpiece inner hole nitriding treatment device, comprising a trolley-type resistance furnace 1 and a workpiece 10 to be processed in a furnace chamber 14 of the trolley-type resistance furnace 1, wherein the workpiece 10 is hollow inside and open at both ends, and the two open ends of the workpiece 10 are respectively sealed and connected with a cover plate 2, wherein one cover plate 2 is provided with an air inlet joint 3, and the other cover plate 2 is provided with an air outlet joint 4; the air inlet joint 3 is connected to an air inlet pipe 5, and the end of the air inlet pipe 5 away from the air inlet joint 3 is connected to an ammonia supply device 6, and the air outlet joint 4 is connected to an air outlet pipe 7, and the end of the air outlet pipe 7 away from the air outlet joint 4 is connected to an exhaust gas treatment device 8, and the ammonia supply device 6 and the exhaust gas treatment device 8 are both located outside the trolley-type resistance furnace 1. In this way, by utilizing the structural characteristics of the workpiece itself, cover plates are directly installed on both ends of the workpiece, and it is converted into a simple muffle tank. By introducing ammonia into the interior of the workpiece, the workpiece only needs to be placed in a common large-scale trolley-type resistance furnace to achieve nitriding hardening treatment of the workpiece cavity; and the outer surface of the workpiece can be hardened by other conventional surface local quenching methods (such as hand-held high-frequency quenching, laser quenching, etc.) or surface treatment methods such as brush plating, so that the investment cost of a single nitrided inner cavity is low.

[0027] In some specific embodiments, reference Figure 1 and Figure 3 The exhaust gas treatment device 8 includes an exhaust gas discharge pipe 81 and a pressure regulating valve 82. The pressure regulating valve 82 is installed at the end of the exhaust pipe 7 away from the exhaust joint 4. The end of the exhaust gas discharge pipe 81 away from the burner is connected to the pressure regulating valve 82. The pressure regulating valve can adjust and control the exhaust volume.

[0028] As an improved implementation, refer to Figure 1 and Figure 3 A detection pipe 9 is connected between the pressure regulating valve 82 and the outlet pipe 7. The detection pipe 9 is connected in sequence to a pressure gauge 91, a first valve 92, a hydrogen probe 93, and a second valve 94. The pressure gauge is used to detect and display the internal pressure of the workpiece; the hydrogen probe is used to measure the decomposition rate of ammonia.

[0029] As an example, the hydrogen probe 93 can adopt the Wuhan Huamin SP-HY-DT / AT integrated hydrogen probe, which has a built-in imported MEMS thermal conductivity sensor. It uses the large difference in thermal conductivity between H2 gas and other gases to measure the hydrogen content in the measured atmosphere. The built-in display screen can fully display / record the changes in hydrogen content in the atmosphere such as nitriding and nitrocarburizing.

[0030] In some specific embodiments, reference Figure 1 and Figure 3 The exhaust pipe 81 is a metal pipe with a plurality of heat dissipation fins 83 on its outer wall. These fins quickly cool the exhaust pipe and dissipate combustion heat, preventing deformation of valves and joints. Specifically, the heat dissipation fins 83 are evenly spaced along the exhaust pipe 81, resulting in a better heat dissipation effect.

[0031] In some specific embodiments, reference Figure 1 and Figure 3 The ammonia supply device 6 includes an ammonia cylinder 61, an air inlet valve 62, and an ammonia inlet pipe 63. The air inlet valve 62 is installed at the end of the air inlet pipe 5 away from the air inlet connector 3. The two ends of the ammonia inlet pipe 63 are respectively connected to the air inlet valve 62 and the ammonia cylinder 61. In this way, the ammonia in the ammonia cylinder can be input into the interior of the workpiece by opening the air inlet valve.

[0032] As a preferred embodiment, the air inlet pipe 5 and the air outlet pipe 7 are both stainless steel pipes that can withstand high temperatures.

[0033] As an improved implementation, refer to Figure 1 and Figure 3 The outer peripheral wall of the vertical section of the gas outlet duct 7 located outside the trolley-type resistance furnace 1 is also provided with heat dissipation fins 83, so as to further improve the heat dissipation effect.

[0034] In some specific embodiments, reference Figure 1 and Figure 4 The trolley-type resistance furnace 1 is a national standard energy-saving periodic operation furnace. Specifically, the trolley-type resistance furnace 1 includes a furnace body 11, a horizontally displaceable trolley 12, and a liftable furnace door device 13. In order to support the workpiece more stably, a plurality of pillow blocks 15 are provided on the upper surface of the trolley 12. In addition, in order to facilitate the arrangement of the air inlet and outlet pipes, the upper surface of the trolley 12 is also provided with at least one pad 16 located between the furnace door device 13 and the trolley 12. In this way, when the furnace door device 13 is closed, a gap 17 is formed between the furnace door device 13 and the trolley 12 for the air inlet and outlet pipes 5 and 7 to pass through. Specifically, the pad 16 is a refractory brick. The cross-sectional shape of the pillow block 15 and the pad 16 are both triangular.

[0035] In some specific embodiments, such as Figure 2 As shown, the workpiece 10 is a box-shaped workpiece or a tube-shaped workpiece.

[0036] In some specific embodiments, such as Figure 2 As shown, the two cover plates 2 are metal plates, and the air inlet connector 3 and the air outlet connector 4 are fixedly connected to the cover plates 2 by welding. The cover plates 2 can be sealed to the openings at both ends of the workpiece 10 by screwing, so that they can be easily disassembled after the nitriding treatment is completed.

[0037] The above embodiments are merely illustrative of the concepts and technical solutions of this utility model and are not intended to limit this utility model. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by persons skilled in the art without departing from the spirit and technical concepts disclosed in this utility model shall be covered by the claims of this utility model.

[0038] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A large workpiece inner hole nitriding treatment device, comprising a trolley-type resistance furnace and a workpiece to be processed located in the furnace chamber of the trolley-type resistance furnace, characterized in that: The workpiece is hollow inside and open at both ends. The open ends of the workpiece are respectively sealed and connected with cover plates, one of which is provided with an air inlet joint, and the other is provided with an air outlet joint; the air inlet joint is connected to an air inlet pipe, and the end of the air inlet pipe away from the air inlet joint is connected to an ammonia supply device, and the air outlet joint is connected to an air outlet pipe, and the end of the air outlet pipe away from the air outlet joint is connected to an exhaust gas treatment device, and the ammonia supply device and the exhaust gas treatment device are both located outside the trolley-type resistance furnace.

2. The large workpiece inner hole nitriding treatment device according to claim 1, characterized in that: The tail gas treatment device includes a tail gas discharge pipe and a pressure regulating valve. The pressure regulating valve is installed at one end of the outlet pipe away from the outlet joint. The end of the tail gas discharge pipe away from the combustion port is connected to the pressure regulating valve.

3. The large workpiece inner hole nitriding treatment device according to claim 2, characterized in that: A detection pipeline is further connected between the pressure regulating valve and the gas outlet pipeline, and the detection pipeline is sequentially connected to a pressure gauge, a first valve, a hydrogen probe and a second valve.

4. The large workpiece inner hole nitriding treatment device according to claim 2, characterized in that: The exhaust gas discharge pipe is a metal pipe, and a plurality of heat dissipation fins are provided on the outer peripheral wall of the exhaust gas discharge pipe.

5. The large workpiece inner hole nitriding treatment device according to claim 4, characterized in that: The heat dissipation fins are distributed at equal intervals along the exhaust pipe.

6. The large workpiece inner hole nitriding treatment device according to claim 1, characterized in that: The ammonia supply device includes an ammonia cylinder, an air intake valve and an ammonia input pipe. The air intake valve is installed at one end of the air intake pipe away from the air intake joint, and the two ends of the ammonia input pipe are respectively connected to the air intake valve and the ammonia cylinder.

7. The large workpiece inner hole nitriding treatment device according to claim 1, characterized in that: The air inlet pipe and the air outlet pipe are both stainless steel pipes.

8. The large workpiece inner hole nitriding treatment device according to any one of claims 1 to 7, characterized in that: The trolley-type resistance furnace includes a furnace body, a horizontally displaceable trolley and a liftable furnace door device. The upper surface of the trolley is provided with a plurality of pillow blocks for supporting workpieces and at least one pad located between the furnace door device and the trolley. A gap is formed between the furnace door device and the trolley for the air inlet duct and the air outlet duct to pass through.

9. The large workpiece inner hole nitriding treatment device according to claim 8, characterized in that: The spacer block is a refractory brick.

10. The large workpiece inner hole nitriding treatment device according to any one of claims 1 to 7, characterized in that: The workpiece is a box-shaped workpiece or a tube-shaped workpiece.

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