HIGH VELOCITY OXY-FUEL (HVOF)
Our company PROCURED WORLD LATEST HVOF SYSTEM FROM TAFA - PRAXAIR Excellence Flame Velocity & Particle Velocity. FLAME TEMPERATURE DURING COATING around 3,000 °C and high bond strength 10,000 psi – HVOF is the latest thermal spray system which is getting wide acceptance worldwide because it finds diverse applications in a cross section of industries.
Coatings applied by our HP/HVOF equipment coatings are characterized by :
- Nearly pore – free density levels
- Low oxide content
- High corrosion resistance
- Good resistance to wear
- Higher bond strength than similar coatings deposited by combustion spry, electric arc spray, or plasma spray processes
HVOF is a thermal spray system utilizing the combustion of gases, such as Hydrogen or a liquid fuel such as kerosene. Fuel and oxygen mix and atomize within the combustion area under conditions that monitor the correct combustion mode and pressure. The process creates a very high velocity which is used to propel the particles at near supersonic speeds before impact onto the substrate. One of the basic rules of spraying is that high combustion pressure = high gas velocity, high particle velocity and resulting high coating quality. One of the key benefits of this system's high velocity is the extremely high coating density and low oxide content. The low oxides are due partly to the speed of the particles spending less time within the heat source and partly due to the lower flame temperature (around 3,000 °C) of the heat source compared with alternative processes.
Typical HVOF Materials :
- Carbides / Cermets (e.g. WC-Co, WC-CoCr, Cr3C2-NiCr)
- Pure Metals (e.g. Al, Cu)
- Stainless Steel (e.g. SS 304, 316, 410)
- Ni – base super alloy (e.g. Inconel, Hasteally, Selffluxing alloy)
- Co – base super alloy (e.g. Stellites, Triballoy)
- MCrAlY (where M = Ni &/ Co &/ Fe)
- For specials applications: Oxide ceramics like Al2O3 typical grain size of spray powder lies between 16 – 45 µm, also finer powders are used.