Thermal spraying#High velocity oxygen fuel spraying .28HVOF.29

The high- velocity flame spraying (HVOF derived from High - Velocity Oxygen Fuel) is a thermal coating process for surface treatment.

Principle of operation

In the high -velocity flame spraying a continuous fuel combustion under high pressure takes place within a water-or air-cooled combustion chamber. A fuel ( such as propane, ethylene, propene, butane, acetylene, hydrogen), liquid fuels (e.g., diesel, kerosene ), as well as combinations of these fuel gases are used. The oxidant is usually oxygen, but also air (common method name: HVAF derived from High - Velocity Air - Fuel). The high pressure generated in the combustion chamber of the burning fuel -oxygen mixture and the (usually downstream ) expansion nozzle produce the required high velocity of the gas jet.

Most powdered (but also known as rods and wires ) spray materials (particle size 1-150 microns ) are fed axially into the combustion chamber or radially in the region of the expansion nozzle. Thus, the spray particles are accelerated to high speeds, leading to very tight spray coatings with excellent adhesion properties. Due to the variable and just enough heat input of the spray material is only slightly changed metallurgically by the injection process.

Applications include: power plants, aerospace, automotive, paper and mechanical engineering industry.

Related Procedures

• Flame spraying,
• Laser spraying,
• Detonation spraying,
• Cold gas spraying,
• Arc spraying,
• Plasma - arc welding,
• Plasma spraying,

• Thermal spraying