INTRODUCTION TO HVOF Coating

custom valve gates

Valve Gate: The core parts of flat gate valves used in the petrochemical industry require high pressure, wear resistance, corrosion prevention against H2S and CO2, especially wellhead and Christmas tree valves have higher requirements. 

Brief Introduction of HVOF TUNGSTEN CARBIDE COATING

High-velocity oxygen-fuel is a new thermal spray technology invented by Browing in the United States in 1981. Nowadays, it is generally called HVOF (High-velocity oxygen-fuel). The flame generated by this technology is a high-temperature, high-speed combustion flame flow generated by using a hydrocarbon-based gas or hydrogen such as propane or propylene, and high-pressure oxygen in a combustion chamber or in a special nozzle. The velocity of the combustion flame can reach more than five Mach (1500 m/s). The axial direction of the powder is fed into the flame, and the sprayed particles can be heated to a molten or semi-molten state. Accelerate the velocity of the combustion flame to a speed of up to 300-500 m/s or even higher, resulting in a high-density, dense, high-quality coating.

The HVOF has a high speed, but the temperature is relatively low, about 300 ° C. For the spraying of WC-Co cemented carbide, the decomposition of WC during spraying can be effectively suppressed. The coating not only has high bonding strength, but also has excellent compactness and abrasive resistance. The abrasive resistance of the coating greatly exceeds that of the plasma sprayed layer, which is equivalent to the explosive sprayed layer and exceeds the hard chrome layer and the sprayed layer. The range of applications is extremely wide.