HVAF19T

1. System Introduction

 

The HVAF19T supersonic flame spraying system is a low-cost, high-efficiency, high-coating quality and high-stability HVAF supersonic spraying system developed based on a similar imported spraying system combined with many years of HVAF spraying system experience of Mancar Mechanical Engineering Co., Ltd. system;

HVAF19T supersonic flame spraying system is composed of human-computer interaction interface, independent gas control cabinet, imported Z40P propane vaporizer, high-performance spray gun, 19F powder feeder, and special pipeline;

Features: HVAF19T supersonic flame spray system adopts imported electronic components and control valve groups; compressed air and propane adopt imported large-flow double closed-loop pressure control valve units; carrier gas and auxiliary gas are controlled by imported precise mass flow controllers To ensure the consistency of coating performance; modular gas control module to ensure the safety of the user site; gas module with leak alarm sensor and system interlock and automatic dilution module;

The imported Z40P propane vaporizer ensures stable vaporization and pressure supply of propane under large flow;

The HVAF19T spray gun adopts an optimized gas distribution based on simulation software. The newly designed coated catalytic combustion plate makes the combustion more complete and the flame flow is more stable; the powder particle flame flow speed is higher, which brings more High-quality coating and more efficient spraying speed; especially the need to use hydrogen for imported equipment can be eliminated (the cancellation of hydrogen indicates higher safety); typical coating performance: spraying WC-10Co-4Cr bonding strength: 80Mpa+ Porosity: <0.5% Coating hardness: HV0.3 1250+; The coating does not peel off when bent at 180 degrees, which is not achieved by traditional HVOF;

The 19F powder feeder is improved on the original imported AT1200 powder feeder; the original DC speed regulating motor is changed to a servo motor (more accurate powder feeding;) The optional weighing module can monitor the powder balance in the powder feeder and Monitor the powder feeding amount per unit time;

 

Main imported parts list: 

Part name	Model	Brand	Remarks	Alternative
System control unit	S7-1200+tp1200	Siemens	Friendly human-computer interaction interface/one-key start/scalability	FX3U 64MR+gs2110
Powder Feeder Servo System	V90	Siemens	Precise speed control = precise and stable powder delivery	MR-E40A/HF-KE
Compressed air precision control unit	QB2TFEC150PSG/DSY15	IMI/Prionoport air	Double closed loop precision pressure control / stable output pressure	Norgren VP5010BJ411H00/11-042-009
Propane explosion-proof pressure control unit	ISF-101A S1070/PSR-2U-V S433	IMI/Prionoport air	Explosion-proof precision pressure control / stable output pressure	Norgren VP5010BJ411H00/11-042-013
Nitrogen mass flow meter	S48 32/HMT 0-50SLM	HORIBA METRON	Accurate mass flow control/accuracy ±0.2%F.S
Mixed gas (hydrogen) mass flow meter	S48 32/HMT 0-30SLM	HORIBA METRON	Accurate mass flow control/accuracy ±0.2%F.S
Pressure Sensor	Setra209/Gems3100	setra/Gems	Accurate pressure measurement/±0.25%F.S
Propane vaporizer	ZIMMER40P	Algas-SDI	With automatic control feedback valve group can maintain stable gaseous propane output pressure

 

2. Working Principle

 

The combustion temperature of the air-fuel mixture is relatively low, so that the sprayed powder particles can be injected along the axial direction of the long and narrow combustion chamber. In the combustion chamber, the lower gas velocity can ensure sufficient heating time for the powder particles. The particles are accelerated in an optimized Laval nozzle. In this way, the powder particle speed can reach above 850-1300m/s. The optimized gas catalytic plate in the combustion chamber can provide a wider range and more stable spraying process parameters.

Coating quality: The combustion temperature of the air-fuel mixture is about 1000 degrees Celsius lower than the temperature of the oxygen-fuel mixture. This temperature is equal to or slightly higher than the melting temperature of the metal, which is ideal for the progressive heating required for cemented carbide and metal powder spraying. In comparison, the initial oxygen content in HVAF process is at least 50% lower than HVOF. These two factors (low temperature and low oxygen) can prevent the powder from being oxidized and the decomposition of carbides in the alloy. Even when the hardness of the tungsten carbide coating is as high as HV0.3=1600, it can still have good ductility.

High efficiency: The powder particles are heated by high pressure in the combustion chamber, and the heat conduction efficiency of the powder is the highest. The design feature of the combustion chamber ensures that the powder particles can stay for a long time in order to be heated. Therefore, compared with other high-speed spraying methods, the energy transmission efficiency of the HVAF process is significantly increased, and the efficiency is significantly accelerated. Taking WC-10Co-4Cr as an example, it can use up to 30kg/h of powder delivery; At the same time, the optimized design of the powder feeding nozzle makes the powder spots pass through the Laval nozzle with a very small beam at high speed, so the powder is fully accelerated and the possibility of sticking to the gun is avoided;

The salient features of HVAF19T spraying process:

1) The heating section is separated from the acceleration section to accurately control the temperature of the material;

2) Axial powder feeding, concentrated beam spot, good coating consistency and high deposition efficiency;

3) Air combustion and cooling, low production cost;

4) Higher impact speed, 850-1300m/s;

5) The improved gas catalytic plate makes the flame more stable, and the deposition efficiency will not be reduced without using hydrogen when spraying tungsten carbide;

 

3. Coating Characteristics

 

Typical coating:

Coating composition: WC-10Co-4Cr

Powder particle size: -30+5µm

Coating hardness: HV0.3 1368

Porosity: <0.5%

Bonding strength: 12000psi (broken in the glue)

Deposition efficiency: 45%+

Coating metallography: 

 

 

Coating composition: WC-CrC-7Ni

Coating hardness: HV0.3 1176

Powder particle size: -30+5µm

Porosity: <1%

Bonding strength: 12000psi (broken in the glue)

Deposition efficiency: 42%+

Coating metallography:

 

 

 

Coating composition: CrC-NiCr (75-25)

Powder particle size: -45+15µm

Coating hardness: HV0.3 937

Porosity: <1%

Bonding strength: 10000psi (broken in the glue)

Deposition efficiency: 35%+

Coating metallography:

 

 

Coating composition: STL20#

Powder particle size: -53+20µm

Coating hardness: HV0.3 732

Porosity: <1%

Bonding strength: 10000psi (broken in the glue)

Deposition efficiency: 65%+

Coating metallography:

 

Note: The deposition efficiency depends on your requirements for the coating; in general, a higher deposition efficiency can be obtained by appropriately relaxing the quality requirements of the coating; but even the coating obtained under high deposition efficiency shows better than HVOF The performance of the coating;

 

Important additional features:

The unique spray gun structure of HVAF19T makes this system have its unique and very economical advantages for sandblasting before spraying;

1) Very low sandblasting consumption and very short sandblasting time; 0.7-1.0kg/m2 5min/m2

2) No special sandblasting room is required;

3) The workpiece does not need to be clamped twice, which effectively avoids the quality and safety hazards of the second clamping and the risk of secondary contamination on the surface of the workpiece;

4) The preheating and sandblasting are completed at the same time, which greatly shortens the pretreatment time.

 

4. Installation Requirements

Power supply:

Control cabinet power supply: AC220V 16A

Propane vaporizer power supply: AC220V 40A

Compressed air:

Air compressor: 12.5m3/min (75kw permanent magnet variable frequency secondary compression air compressor) (recommended 90kw permanent magnet variable frequency secondary compression air compressor)

Exhaust pressure: 1.0Mpa

Equipped with a cold dryer and adsorption dryer with sufficient processing capacity (recommended micro-heat regeneration type)

Pipeline interface: equipped with a 1-1/2 internal wire ball valve; 1-1/2F type union;

Propane:

Use 50kg bottled propane with gas-liquid two-phase interface and liquid phase outlet; no pressure reducing valve is required;

Nitrogen: large flow two-stage nitrogen pressure reducer

    The maximum pressure is 120Psi; the maximum flow is 30L/min; 3/8 card socket interface;

Mixed gas: (optional hydrogen) cannot be used

    The maximum pressure is 120Psi; the maximum flow is 20L/min; 3/8 card socket interface; with backfire preventer;

Note: The maximum pressure of nitrogen and hydrogen cannot exceed 120Psi