High speed flame spraying
The high velocity flame spraying (HVOF, derived from H IgH V elocity- O xygen- F uel) is a thermal coating process for the surface treatment.
Working principle
In high-speed flame spraying, fuel is burned continuously under high pressure within a water- or air-cooled combustion chamber . The fuels used are combustion gases (such as propane , ethylene , propene , butane , acetylene , hydrogen ), liquid fuels (e.g. diesel , kerosene ) and combinations of these. The oxidizing agent is mostly oxygen , but also air (common process name: HVAF, derived from H igh- V elocity- A ir- F uel). The high pressure of the burning fuel-oxygen mixture generated in the combustion chamber and the (mostly downstream) expansion nozzle ( Laval nozzle ) generate the required high speed of the gas jet.
Mostly powdery (but also as rods and wires) spray materials (grain size 1–150 µm) are fed axially in the combustion chamber or radially in the area of the expansion nozzle. This accelerates the spray particles to the high speeds that lead to very dense spray coatings with excellent adhesive properties . Due to the adjustable and just sufficient heat input, the spraying material is only slightly changed metallurgically by the spraying process.
Areas of application are: power plant construction, aviation, automobile, paper and mechanical engineering industries.
Related procedures
- Flame spraying ,
- Laser spraying ,
- Detonation syringes ,
- Cold gas spraying ,
- Arc spraying ,
- Plasma powder deposition welding ,
- Plasma spraying ,
Individual evidence
- ↑ Archive link ( Memento of the original from December 5, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
