High velocity oxy-fuel process | hvof coatings | flame spray coatings

High Velocity Oxy-Fuel

Introduction

HVOF spraying has been developed principally to produce high quality metal and carbide coatings equivalent to the D - Gun process and with superior properties to conventional flame spray processes

Main Applications

Rotary knife blades
Aero engine parts
Gate valves
Pistons
Shafts

Process Description

The HVOF process typically uses oxygen and hydrogen as the fuel gases to give coatings of the highest quality.

Mixing of the gases occurs inside the gun and the externally ignited flame reaches a temperature of about 2700ºC.

Powder material is injected through the flame and the molten particles projected at velocities approaching 550 metres per second onto the workpiece.

Precise control of all spraying parameters and powder feed rates, and the use of a robot to precisely position the gun, enables high quality coatings to be repeated on a large variety of different components.

General Coating Characteristics

high bond strength (83 MPa - 12000 p.s.i.).
high density, low porosity
low oxide.
high hardness (DPH 500 1000 - 1300 for WC/Co).
fine as sprayed texture, able to be ground or lapped to a fine finish (0.1-0.2 microns).
excellent resistance to wear by abrasion, erosion or fretting.