An HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings

Abstract

This invention discloses an HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings, comprising: a barrel cooling sleeve, a barrel, an air chamber sleeve, a combustion chamber, a gun body shell, an extended fixing sleeve, a fixing bracket, an isolating plate, a gas mixer, a powder feeding needle fixing nut, a gas dispersion isolator, a rear cover, a powder feeding needle fixing mandrel, an extended powder feeding needle, and a gas mixing chamber. This invention solves the technical problem of existing HVAF spray guns easily sticking to the barrel or combustion chamber when spraying iron-based amorphous powders.

Description

Technical Field

[0001] This invention belongs to the field of thermal spraying technology, and particularly relates to an HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings. Background Art

[0002] Iron-based amorphous materials possess a single, disordered amorphous structure, free from crystal defects such as dislocations and grain boundaries. Therefore, iron-based amorphous coatings exhibit excellent corrosion resistance. Furthermore, iron-based amorphous materials possess extremely high hardness and strength, and demonstrate outstanding aging resistance, impact resistance, and high-temperature resistance. They hold promise as a replacement for traditional resin-based anti-slip coatings for wear-resistant and anti-slip coatings on large ships.

[0003] The preparation processes for iron-based amorphous coatings include atmospheric plasma spraying (APS), arc spraying (AS), and high-velocity vapor deposition (HVAF and HVOF). Among these, HVAF spraying produces iron-based amorphous coatings with the best basic properties such as amorphous content, oxygen content, porosity, and bonding strength, exhibiting superior wear and corrosion resistance and demonstrating great application potential. However, due to the low melting point of iron-based amorphous materials, the particles melt within the combustion chamber and nozzle, resulting in high viscosity. Some molten particles collide with the inner walls of the combustion chamber and nozzle, adhering to the pipe walls and causing reduced deposition efficiency and spray gun malfunctions. Currently, mainstream HVAF spray guns on the market, such as Kermetico's AK7 spray gun and Uniquecoat's M3 and M2 spray guns, all exhibit significant clogging when continuously spraying iron-based amorphous powder for half an hour, limiting their application in actual industrial production. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings, thus solving the technical problem that existing HVAF spray guns are prone to sticking to the gun barrel or combustion chamber when spraying iron-based amorphous powders.

[0005] The objective of this invention is achieved through the following technical solution: An HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings includes: a barrel cooling sleeve, a barrel, an air chamber sleeve, a combustion chamber, a gun body shell, an extended fixing sleeve, a fixing bracket, an isolation plate, a gas mixer, a powder feeding needle fixing nut, a gas dispersion isolator, a rear cover, a powder feeding needle fixing mandrel, an extended powder feeding needle, and a gas mixing chamber; wherein, the tail end of the barrel is fixed to the front end of the combustion chamber; the isolation plate is located at the rear end inside the combustion chamber; the gas mixer is assembled at the rear end of the combustion chamber; the gas dispersion isolator is fixed at the rear end of the gas mixer, and the rear cover presses against the gas dispersion isolator; a gas mixing chamber is formed between the gas mixer and the gas dispersion isolator; the rear cover is connected to the gun body shell; the extended fixing sleeve, the fixed bracket ... The extended powder delivery needle passes sequentially through the central hole of the rear cover, the central hole of the gas dispersion isolator, the central hole of the gas mixer, and the central hole of the isolation plate, extending to the middle of the combustion chamber; the tail of the extended powder delivery needle is fixed to the rear end of the gun body shell; the middle part of the extended powder delivery needle is fixed to the inner cavity of the gas mixer by a powder delivery needle fixing nut; the front end of the extended powder delivery needle is connected to the fixing bracket, and the extended fixing sleeve is sleeved on the outer surface of the fixing bracket, covering the front end of the extended powder delivery needle; the powder delivery needle fixing mandrel is sleeved on the outer surface of the extended powder delivery needle, and the outer periphery of the powder delivery needle fixing mandrel is connected to the rear cover and the gas mixer respectively; the front end of the gun body shell is connected to the air chamber sleeve; the front end of the air chamber sleeve is connected to the gun barrel cooling sleeve.

[0006] The HVAF spray gun structure described above, suitable for stable spraying of iron-based amorphous coatings, further includes: a nozzle fixing screw, an M-shaped screw hole, and a clamping washer; wherein, the tail end of the gun barrel is fixed to the front end of the combustion chamber by the nozzle fixing screw and the clamping washer; the nozzle fixing screw engages with the M-shaped screw hole opened at the front end of the combustion chamber.

[0007] The HVAF spray gun structure described above, which is suitable for stable spraying of iron-based amorphous coatings, further includes: a rear cover locking screw; wherein the rear cover is connected to the gun body shell by the rear cover locking screw.

[0008] The HVAF spray gun structure applicable to stable spraying of iron-based amorphous coatings also includes: a rear cover clamping nut and a powder feeding needle locking nut; wherein, the tail of the extended powder feeding needle is fixed to the rear end of the gun body shell by the rear cover clamping nut and the powder feeding needle locking nut.

[0009] The HVAF spray gun structure described above, suitable for stable spraying of iron-based amorphous coatings, further includes: a sleeve locking screw; wherein, the front end of the gun body shell is connected to the air chamber sleeve through the sleeve locking screw.

[0010] In the HVAF spray gun structure described above, which is suitable for stable spraying of iron-based amorphous coatings, the M-thread at the rear end of the extended powder feeding needle is connected to the powder feeding tube.

[0011] In the HVAF spray gun structure described above, suitable for stable spraying of iron-based amorphous coatings, the rear cover has a gas input interface; the gas dispersion isolator has a first small hole; the side wall of the gas mixer has an air input hole, and the front end of the gas mixer has a second small hole; the isolator has a third small hole; the side wall of the air chamber sleeve has a main air interface; the gap between the gun body shell, air chamber sleeve, and gun barrel cooling sleeve as a whole and the gun barrel, combustion chamber, gas mixer, gas dispersion isolator, and rear cover as a whole forms an air cooling channel; the rear cover has a vertical powder feeding needle cooling air channel; the air cooling channel is connected to the powder feeding needle cooling air channel and the air input hole respectively; the front end of the gun barrel cooling sleeve has a fourth small hole.

[0012] In the HVAF spray gun structure described above, suitable for stable spraying of iron-based amorphous coatings, combustion gas enters through the gas input interface on the rear cover, and then enters the gas mixing chamber through the first small hole on the gas dispersion isolator. It mixes evenly with the air entering through the air input hole on the gas mixer, then enters the rear end of the combustion chamber through the second small hole at the front end of the gas mixer, and finally is smoothly transmitted to the inner cavity of the combustion chamber through the evenly distributed third small holes on the isolator. After combustion, the combustion gas and air enter the gun barrel and are finally sprayed onto the substrate surface. Compressed air is injected through the main air interface on the air chamber sleeve and fills the air cooling channel. Part of the compressed air cools the gun barrel and combustion chamber and is discharged through the fourth small hole distributed at the front end of the gun barrel cooling sleeve; part of the compressed air acts as a combustion-supporting gas entering the air input hole; and another part of the compressed air enters the outer cavity of the extended powder delivery needle through the powder delivery needle cooling gas channel to cool the extended powder delivery needle.

[0013] In the HVAF spray gun structure applicable to the stable spraying of iron-based amorphous coatings described above, the ignition system is located on the spark plug fixing screw hole in the middle of the combustion chamber.

[0014] In the HVAF spray gun structure described above, which is suitable for stable spraying of iron-based amorphous coatings, the main gas in the combustion gas is propane, propylene, or a mixture of the two, and the auxiliary gas is hydrogen; nitrogen is used as the powder feeding gas and is injected from the rear end of the extended powder feeding needle.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) This invention solves the technical problem that existing HVAF spray guns are prone to sticking to the gun barrel or combustion chamber when spraying iron-based amorphous powders; through technical approaches such as spray gun structure system design, gun barrel optimization, powder feeding needle size extension and sleeve spraying thermal barrier coating, an HVAF spray gun suitable for long-term stable spraying of iron-based amorphous coatings is prepared, which is easy to install and disassemble and has low maintenance cost. The sprayed coating has a high degree of amorphousness, good density and corrosion resistance, and achieves multiple functions such as wear resistance, anti-slip and anti-corrosion.

[0017] (2) The barrel length of the present invention is relatively short (120mm, while the conventional barrel length is more than 200mm). Therefore, the HVAF jet velocity is relatively low and the temperature is relatively high, making it suitable for spraying Fe-based amorphous powder.

[0018] (3) The present invention extends the powder feeding needle to the middle of the combustion chamber, which is more in line with the aerodynamic environment at the front end of the combustion chamber and can effectively prevent the powder from sticking and clumping at the outlet of the combustion chamber.

[0019] (4) Since the melting point of iron-based amorphous powder is low, after the powder feeding needle of the present invention is lengthened, the residence time of powder in the combustion chamber is shortened, the particles will not be over-melted, and a coating with an amorphous content of more than 90% can be prepared.

[0020] (5) The powder feeding needle of the present invention is covered with an extended fixing sleeve coated with a thermal barrier coating. Even in the high temperature environment of the combustion chamber exceeding 2000°C, it can be used for a long time without burning.

[0021] (6) The present invention continuously sprays Fe-based amorphous powder for more than 5 hours, and there is no adhesion or obvious burning of the various parts of the spray gun. The density of the sprayed coating reaches more than 99%, and the coating has no obvious rust after 1000 hours of neutral salt spray corrosion. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0023] Figure 1 This is a schematic diagram of the HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings provided in an embodiment of the present invention. Detailed Implementation

[0024] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic diagram of the HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings provided in an embodiment of the present invention. Figure 1 As shown, the HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings includes: a barrel cooling sleeve 1, a barrel 2, an air chamber sleeve 3, a sleeve locking screw 5, a nozzle fixing screw 6, an M6 screw hole 7, a clamping washer 8, a combustion chamber 9, a gun body shell 10, an extended fixing sleeve 12, a fixing bracket 13, an isolating plate 14, a gas mixer 15, a powder feeding needle fixing nut 16, a gas dispersion isolator 18, a rear cover 19, a rear cover locking screw 20, an M10 thread 21, a powder feeding needle fixing spindle 22, an extended powder feeding needle 23, a rear cover clamping nut 24, a powder feeding needle locking nut 25, and a gas mixing chamber 26. Among these,

[0026] The tail of the barrel 2 is fixed to the front end of the combustion chamber 9 by the nozzle fixing screw 6 and the clamping washer 8; the nozzle fixing screw 6 is engaged with the M6 ​​screw hole 7 opened at the front end of the combustion chamber 9; the isolation plate 14 is located inside the rear end of the combustion chamber 9; the gas mixer 15 is assembled at the rear end of the combustion chamber 9.

[0027] The gas dispersion isolator 18 is fixed to the rear end of the gas mixer 15, and the rear cover 19 presses down on the gas dispersion isolator 18; a gas mixing chamber 26 is formed between the gas mixer 15 and the gas dispersion isolator 18; the rear cover 19 is connected to the gun body shell 10 by a rear cover locking screw 20; the extended powder delivery needle 23 passes through the center hole of the rear cover 19, the center hole of the gas dispersion isolator 18, the center hole of the gas mixer 15 and the center hole of the isolation plate 14 in sequence, extending to the middle of the combustion chamber 9; the tail of the extended powder delivery needle 23 is fixed to the rear end of the gun body shell 10 by the rear cover clamping nut 24 and the powder delivery needle locking nut 25; the middle part of the extended powder delivery needle 23 is connected to the combustion chamber 9 by the powder delivery needle 18. The needle fixing nut 16 is fixed in the inner cavity of the gas mixer 15; the front end of the extended powder delivery needle 23 is connected to the fixing bracket 13, and the extended fixing sleeve 12 is sleeved on the outer surface of the fixing bracket 13, covering the front end of the extended powder delivery needle 23; the powder delivery needle fixing mandrel 22 is sleeved on the outer surface of the extended powder delivery needle 23, and the outer periphery of the powder delivery needle fixing mandrel 22 is connected to the rear cover 19 and the gas mixer 15 respectively; the front end of the gun body shell 10 is connected to the air chamber sleeve 3 through the sleeve locking screw 5; the front end of the air chamber sleeve 3 is connected to the gun barrel cooling sleeve 1; the M10 thread 21 at the rear end of the extended powder delivery needle 23 is connected to the powder delivery pipe.

[0028] The rear cover 19 has a gas input interface 27; the gas dispersion isolator 18 has a first small hole; the side wall of the gas mixer 15 has an air input hole 17, and the front end of the gas mixer 15 has a second small hole; the isolation plate 14 has a third small hole; the side wall of the air chamber sleeve 3 has a main air interface 4; the gap between the gun body shell 10, the air chamber sleeve 3, and the gun barrel cooling sleeve 1 as a whole, and the gun barrel 2, the combustion chamber 9, the gas mixer 15, the gas dispersion isolator 18, and the rear cover 19 as a whole, forms an air cooling channel 29; the rear cover 19 has a vertical powder feeding needle cooling air channel 28; the air cooling channel 29 is connected to the powder feeding needle cooling air channel 28 and the air input hole 17 respectively; the front end of the gun barrel cooling sleeve 1 has a fourth small hole.

[0029] Combustion gas enters through the gas input interface 27 on the rear cover 19, and enters the gas mixing chamber 26 through the first small hole on the gas dispersion isolator 18. It is then mixed evenly with the air entering through the air input hole 17 on the gas mixer 15. Finally, it enters the rear end of the combustion chamber 9 through the second small hole at the front end of the gas mixer 15, and is then smoothly transmitted to the inner cavity of the combustion chamber 9 through the evenly distributed third small holes on the isolation plate 14. After combustion, the combustion gas and air enter the gun barrel and are finally sprayed onto the surface of the substrate.

[0030] Compressed air is injected through the main air interface 4 on the air chamber sleeve 3 and fills the air cooling channel 29. Part of the compressed air cools the barrel 2 and the combustion chamber 9 and is discharged through the fourth small hole distributed at the front end of the barrel cooling sleeve 1; part of the compressed air enters the air inlet 17 as combustion-supporting gas; and another part of the compressed air enters the outer cavity of the extended powder delivery needle 23 through the powder delivery needle cooling gas channel 28 to cool the extended powder delivery needle 23.

[0031] The barrel 2 is located at the front end of the spray gun. The rear end of the barrel 2 is fixed to the front end of the combustion chamber 9 by the spray gun fixing screw 6 and the clamping washer 8. The spray gun fixing screw 6 mates with the four M6 screw holes 7 at the front end of the spray gun. The isolation plate 14 is located inside the rear end of the combustion chamber 9. The gas mixer 15 is assembled at the rear end of the combustion chamber 9 and clamps the isolation plate 14. The gas dispersion isolator 18 is fixed to the rear end of the gas mixer 15 and clamped by the rear cover 19. The rear cover 19 is connected to the gun body shell 10 by the rear cover locking screw ring 20. The extended powder delivery needle 23 passes through the center holes of the rear cover 19, the gas dispersion isolator 18, the gas mixer 15, and the isolation plate 14 in sequence, extending to the middle of the combustion chamber 9. The rear end of the extended powder delivery needle 23 is fixed to the rear end of the gun body shell 10 by the rear cover clamping nut 24 and the powder delivery needle locking nut 25. The middle position of the extended powder delivery needle 23 is fixed to the inner cavity of the gas mixer 15 by the powder delivery needle fixing nut 16. The extended fixed sleeve 12 is supported by a fixed bracket 13 at the front end. To ensure concentricity, a powder delivery needle fixing mandrel 22 is placed between the rear cover 19, the gas dispersion isolator 18, the gas mixer 15, and the extended powder delivery needle 23. The front end of the gun body shell 10 is fixed to the air chamber sleeve 3 with a sleeve locking screw 5. The front end of the air chamber sleeve 3 is connected to the gun barrel cooling sleeve 1 by a thread. The front end of the gun barrel cooling sleeve 1 is flush with the front end of the gun barrel 2, with a small assembly gap in the radial direction. The gun barrel 2 uses a steel Laval tube with a length of only 120mm, which has the advantage of reducing powder adhesion to the nozzle. The powder delivery needle 23 is extended and extends to the middle of the combustion chamber 9, and a thermal barrier coating is sprayed on the extended fixed sleeve 12 at the end. The advantage of the extended fixed sleeve 12 is that it can protect the powder delivery needle from high-temperature erosion in the combustion chamber, while the thermal barrier coating on the surface can significantly reduce the length of the extended fixed sleeve 12 and improve working stability.

[0032] Combustion gas (usually propane, propylene, or a mixture thereof as the main gas, and hydrogen as the auxiliary gas) enters through the gas input port 27 on the rear cover 19, and enters the gas mixing chamber 26 through the first small hole on the gas dispersion isolator 18. It mixes evenly with the air (combustion-supporting gas) entering through the air input port 17 on the gas mixer 15, then enters the rear end of the combustion chamber 9 through the second small hole at the front end of the gas mixer 15, and finally is smoothly transmitted to the inner cavity of the combustion chamber 9 through the evenly distributed third small holes on the isolation plate 14. After combustion, the combustion gas and air enter the gun barrel and are finally sprayed onto the substrate surface. Compressed air is injected through the main gas air port 4 on the air chamber sleeve 3 and fills the air cooling channel 29. The air cooling channel 29 is formed by the gap between the gun body shell 10, the air chamber sleeve 3, the gun barrel cooling sleeve 1, the gun barrel 2, the combustion chamber 9, the gas mixer 15, the gas dispersion isolator 18, and the rear cover 19. Part of the compressed air cools the gun barrel 2 and the combustion chamber 9 and is discharged through the fourth small hole distributed at the front end of the gun barrel cooling sleeve 1. Part of the compressed air enters the air inlet hole 17 as the combustion-supporting gas, as mentioned above. Another part enters the outer cavity of the extended powder feeding needle 23 through the powder feeding needle cooling gas channel 28 and serves as the powder feeding needle cooling gas. Nitrogen gas is used as the powder feeding gas and carries Fe-based spray powder. It is injected from the rear end of the extended powder feeding needle 23. The powder feeding pipe is connected to the M10 thread 21 at the rear end of the extended powder feeding needle 23. After continuous spraying of Fe-based amorphous powder for more than 5 hours, there was no obvious adhesion between the inner walls of the gun barrel 2 and the combustion chamber 9. The extended powder feeding needle 23 and the extended fixing sleeve 12 were not burned. The amorphous content of the sprayed coating was more than 90%, and the density reached more than 99%. At the same time, the coating showed no obvious rust after 1000 hours of neutral salt spray corrosion.

[0033] The HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings also includes an ignition system; wherein the ignition system is disposed on the spark plug fixing screw hole 11 in the middle of the combustion chamber 9. The ignition system consists of an ignition coil and a spark plug, which can realize pulse ignition, and the spark plug is fixed on the spark plug fixing screw hole 11 in the middle of the combustion chamber 9.

[0034] The locking and fixing device is basically connected by threads, and the screws and nuts used are all in accordance with national standards; the mating surfaces of the extended powder feeding needle 23, rear cover 19, gas dispersion isolator 18, gas mixer 15, etc. are sealed with O-ring rubber seals; the equipment is easy and quick to load and unload, and the cost of replacing parts is low.

[0035] Compressed air enters the spray gun through the main air inlet 4, and fuel gas enters the spray gun through the fuel gas inlet 27. After being thoroughly mixed through the closely spaced small holes on the fuel gas distributor 18 and fuel gas mixer 15, the fuel gas enters the combustion chamber 9. The spark plug installed on the spark plug fixing screw hole 11 discharges pulses under program control, igniting the mixed fuel gas in the combustion chamber 9 to form a high-pressure, high-speed flame. After being accelerated by the Laval gun barrel 2, the flame is sprayed onto the workpiece to be coated. During spraying, the combustion chamber, gun barrel, and extended powder delivery needle will face a large heat flow. The compressed air will flow at high speed through the air cooling channel 29 to carry away the heat, thereby maintaining a low temperature.

[0036] This embodiment solves the technical problem of existing HVAF spray guns easily sticking to the barrel or combustion chamber when spraying iron-based amorphous powders. Through technical approaches such as spray gun structure system design, barrel optimization, powder feed needle lengthening, and sleeve spraying of thermal barrier coatings, an HVAF spray gun suitable for long-term stable spraying of iron-based amorphous coatings, with simple loading and unloading and low maintenance costs, has been prepared. The sprayed coating has a high degree of amorphization, good density and corrosion resistance, achieving multiple functions such as wear resistance, anti-slip, and corrosion resistance. The barrel length of this embodiment is shorter (120mm, while conventional gun barrel lengths are over 200mm), therefore, the HVAF jet velocity is relatively low and the temperature is higher, making it suitable for spraying Fe-based amorphous powders. This embodiment lengthens the powder feed needle... Extending to the middle of the combustion chamber better suits the aerodynamic environment at the front of the combustion chamber, effectively preventing powder adhesion and agglomeration at the combustion chamber outlet. Due to the low melting point of iron-based amorphous powder, the extended powder feeding needle in this embodiment shortens the residence time of the powder in the combustion chamber, preventing over-melting of particles and enabling the preparation of a coating with an amorphous content exceeding 90%. The powder feeding needle in this embodiment is further enhanced by an extended fixing sleeve coated with a thermal barrier coating, allowing for long-term use without burn-out even in high-temperature environments exceeding 2000°C in the combustion chamber. In this embodiment, continuous spraying of Fe-based amorphous powder for more than 5 hours resulted in no adhesion or significant burn-out of any parts of the spray gun, achieving a density of over 99% after spraying. Furthermore, the coating showed no significant rust after 1000 hours of neutral salt spray corrosion.

[0037] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An HVAF spray gun structure suitable for stable spraying of iron-based amorphous coatings, characterized in that... include: The gun includes a barrel cooling sleeve (1), a barrel (2), an air chamber sleeve (3), a combustion chamber (9), a gun body shell (10), an extended fixing sleeve (12), a fixing bracket (13), an isolating plate (14), a gas mixer (15), a powder feeding needle fixing nut (16), a gas dispersion isolator (18), a rear cover (19), a powder feeding needle fixing spindle (22), an extended powder feeding needle (23), and a gas mixing chamber (26); among which, The tail of the barrel (2) is fixed to the front end of the combustion chamber (9); The isolation plate (14) is located at the rear end inside the combustion chamber (9); The gas mixer (15) is mounted at the rear end of the combustion chamber (9); The gas dispersion isolator (18) is fixed to the rear end of the gas mixer (15), and the rear cover (19) presses down on the gas dispersion isolator (18); a gas mixing chamber (26) is formed between the gas mixer (15) and the gas dispersion isolator (18); The rear cover (19) is connected to the gun body shell (10); The extended powder feeding needle (23) passes through the central hole of the rear cover (19), the central hole of the gas dispersion isolator (18), the central hole of the gas mixer (15), and the central hole of the isolation plate (14) in sequence, extending to the middle of the combustion chamber (9); The tail of the extended powder feeding needle (23) is fixed to the rear end of the gun body shell (10); The middle part of the extended powder feeding needle (23) is fixed to the inner cavity of the gas mixer (15) by the powder feeding needle fixing nut (16); The front end of the extended powder feeding needle (23) is connected to the fixed bracket (13), and the extended fixed sleeve (12) is sleeved on the outer surface of the fixed bracket (13), covering the front end of the extended powder feeding needle (23). The powder feeding needle fixing spindle (22) is sleeved on the outer surface of the extended powder feeding needle (23), and the outer periphery of the powder feeding needle fixing spindle (22) is connected to the rear cover (19) and the gas mixer (15) respectively. The front end of the gun body shell (10) is connected to the air chamber sleeve (3); The front end of the air chamber sleeve (3) is connected to the barrel cooling sleeve (1).

2. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that... Also includes: Nozzle fixing screw (6), M6 screw hole (7), and clamping washer (8); among which, The tail of the gun barrel (2) is fixed to the front end of the combustion chamber (9) by a nozzle fixing screw (6) and a clamping washer (8); The nozzle fixing screw (6) engages with the M6 ​​screw hole (7) at the front end of the combustion chamber (9).

3. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that... It also includes: a rear cover locking screw ring (20); among which, The rear cover (19) is connected to the gun body shell (10) by a rear cover locking screw (20).

4. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that... It also includes: a rear cover clamping nut (24) and a powder feeding needle locking nut (25); among which, The tail of the extended powder feeding needle (23) is fixed to the rear end of the gun body shell (10) by the rear cover clamping nut (24) and the powder feeding needle locking nut (25).

5. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that... It also includes: sleeve locking screw (5); among which, The front end of the gun body shell (10) is connected to the air chamber sleeve (3) through the sleeve locking screw (5).

6. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that: The M10 thread (21) at the rear end of the extended powder feeding needle (23) is connected to the powder feeding tube.

7. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that: The rear cover (19) is provided with a gas input interface (27); The gas dispersion isolator (18) has a first small hole; The gas mixer (15) has an air inlet hole (17) on its side wall and a second small hole at its front end. The isolation plate (14) has a third small hole; The side wall of the air chamber sleeve (3) is provided with a main air interface (4); The gap between the gun body shell (10), the air chamber sleeve (3) and the barrel cooling sleeve (1) as a whole and the barrel (2), the combustion chamber (9), the gas mixer (15), the gas dispersion isolator (18) and the rear cover (19) as a whole forms an air cooling channel (29); The rear cover (19) has a vertical powder feeding needle cooling air channel (28); the air cooling channel (29) is connected to the powder feeding needle cooling air channel (28) and the air inlet (17) respectively; The front end of the barrel cooling sleeve (1) is provided with a fourth small hole.

8. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 7, characterized in that: Combustion gas enters through the gas input port (27) on the rear cover (19), and enters the gas mixing chamber (26) through the first small hole on the gas dispersion isolator (18), and is evenly mixed with the air entering through the air input hole (17) on the gas mixer (15). Then, it enters the rear end of the combustion chamber (9) through the second small hole at the front end of the gas mixer (15), and finally is smoothly transmitted to the inner cavity of the combustion chamber (9) through the evenly distributed third small holes on the isolation plate (14). After combustion, the combustion gas and air enter the gun barrel and are finally sprayed onto the surface of the substrate. Compressed air is injected through the main air interface (4) on the air chamber sleeve (3) and fills the air cooling channel (29). Part of the compressed air cools the gun barrel (2) and the combustion chamber (9) and is discharged through the fourth small hole distributed at the front end of the gun barrel cooling sleeve (1). Part of the compressed air enters the air input hole (17) as combustion-supporting gas. Another part of the compressed air enters the outer cavity of the extended powder delivery needle (23) through the powder delivery needle cooling gas channel (28) to cool the extended powder delivery needle (23).

9. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 1, characterized in that... It also includes: an ignition system; wherein the ignition system is disposed on the spark plug fixing screw hole (11) in the middle of the combustion chamber (9).

10. The HVAF spray gun structure for stable spraying of iron-based amorphous coatings according to claim 8, characterized in that: In the combustion gas, the main gas is propane, propylene or a mixture of the two, and the auxiliary gas is hydrogen; nitrogen is used as the powder feeding gas and is injected from the rear end of the extended powder feeding needle (23).

Images