Kermetico HVAF systems and technology

HVAF – Description of the High Velocity Air-Fuel Spraying Process

High Velocity Air-Fuel Kermetico (Kermetico HVAF) is a thermal spray process that produces high-quality coatings from metals, alloys, carbides and borides on metallic substrates.

The coating material in the form of alloy or composite powders is fed to the Kertmetico HVAF burner. The burner uses compressed air to burn fuel (propane, propylene, natural gas, etc.), creating a high velocity stream of gases generated in the combustion process. In this stream, the powder is heated and accelerated to form a coating at the moment of impact on the substrate.

The quality and efficiency of the Kermetico system group results from the relatively low ignition temperature of the air / fuel mixture, in combination with the axial delivery of powder through a long combustion chamber, where the low gas velocity allows a sufficiently long time to gradually heat the powder particles. The material acceleration occurs in a large diameter nozzle. The large diameter of the nozzle is needed to flow a considerable volume of nitrogen, present in the air used for combustion. This also ensures that the nozzle walls do not interact with the particles. This allows the use of a nozzle that is long enough that it is possible to properly accelerate the powder, usually from 800 to over 1200 m / s. A catalytic ceramic cartridge is used in the combustion chamber to provide a wide range of stable combustion parameters.

Precise control of the temperature of the powder at the melting point and the high velocities of the collision of particles with the substrate are characteristic parameters that distinguish the Kermetico HVAF process from others.

Configuration diagram of the Kermetico HVAF device

Quality of the HVAF coating

The combustion temperature of air-fuel mixtures is usually 1000 °C lower than in the oxy-fuel combustion. This lower temperature is ideal for the gradual heating of metal particles and sintered carbides to or slightly above the melting point of metals. In comparison to HVOF processes, the initial oxygen content in the gas mixture is 5 times lower for the HVAF process.

Both of these factors prevent oxidation of the metal and decomposition of carbides and diffusion of carbides to the metallic matrix. These factors allow the coating to retain the original plasticity of the powder coating material, even if the hardness of the cemented carbide coating exceeds 1700 HV300.

Kermetico HVAF Systems

The Kermetico AK HVAF device applies coatings with 5-6 times higher performance, 20-30% higher deposition efficiency and 30% less spread than any other HVOF system. Choosing Kermetico AK, the HVOF coating manufacturer reduces the production cost by at least 50% of those incurred by competitors using HVOF, and thanks to the better quality of coatings, it obtains an additional advantage over the competition.

WC/Co/Cr właściwości powłokiTypowa dla HVOFKermetico HVAF – konfiguracja palnika
EconomyBalancedUltra-quality
Sprawność procesu, %40-5560-7048-5836-42
Twardość, HV3001050-12501050-12501250-13501350-1600+
Porowatość (metalografia)<0.8<0.8<0.5<0.3
Przyczepność (dla grubości 1.00 mm), MPa80+
Chropowatość powierzchni po natrysku, µm3.5-4.51-3.2
Maksymalna grubość powłoki, mm121231.5

The Kermetico AK device is also used for applying coatings from Ag, Al, Cu, Sn, Ti and other materials considered to be atypical for HVOF.

Oxidiser and coolant: Compressed air, Pressure in the range of 8-11.5 bar (115-165 PSIG).

Fuel: Propane, Propylene, Propane-Butane (LPG), or natural gas. Pressure: 7-11.5 bar (100-165 PSIG).

Palniki AK HVAF KermeticoPalnikOpisMax wydajność/h
AK7Duże detale o średnicy powyżej >200 mm33+ kg
Palnik dużej mocy z szerokim zakres ciśnień w komorze spalania do nanoszenia wysokiej jakości powłok na dużych powierzchniach.
Najniższy koszt natrysku dużych detali.
Najniższy stopień utlenienia materiału powłokowego.
AK6Uniwersalny palnik do węglików dla detali o średnicy 5-250 mm28 kg
Palnik zaprojektowany do natrysku węglika wolframu na detale o różnorodnej geometrii. 70% mocy palnika AK7.
AK5Mały palnik do natrysku małych detali15 kg
Powłoki z metali, stopów i węglików dla detali o średnicy poniżej 200 mm, średnicy wewnętrznej od 200 mm , cienkościenne złożone kształty.
AK-HHPalnik ręczny do natrysku skomplikowanych geometrii15 kg
Uniwersalny palnik ręczny wyposażony z uchwytem do robota.
Do natrysku metali, stopów I węglików.
Waga palnika: 2.5 kg (5 lbs.)

AK-IDMinimalna średnica wewnętrzna 80 mm
Głowica obrotowa, średnica minimum 100 mm
5 kg
AK-IDR
Chłodzenie powietrzem; wielogodzinna praca przy natrysku średnic wewnętrznych. Kąt natrysku – 90°.
Each burner, with the exception of ID burners, can be configured for Ultra (highest speeds), Economy (highest efficiency / DE), or Balanced and can be used for surface preparation (sanding) and for coating.

Kermetico powder control consoles and feeders

Selected features of Kermetico AK Systems

    • Industrial Controller / tablet IP67 + PLC controller;
    • Unlimited number of saved programs;
    • One system fits all burners;
    • Variety of powder feeders and gas evaporators;
    • Custom-made systems and burners;
    • and more.

Kermetico HVAF equipment for sale

Since the day the company was founded in 2006, we installed over 60 HVAF systems worldwide. Some of them work at universities or in government and industrial laboratories, but the vast majority have found application in production.

Our devices can be equipped with various burners; they are durable and technically efficient. And they are not expensive. Assuming you spray tungsten carbide for 3 hours a day, the cost of the investment returns after 3 months.

Contact our local representative for additional information.

 

We are looking forward to doing business with You!

 

HVAF description (pl)

HVAF and HVOF comparion (pl)