The HVOF method
The HVOF method is a process for refinement of screw conveyors. The screw conveyors made of tool steel are roughened to start. A gas mix is now ignited with a special gun, which causes the metallic powder particles to melt, and they are shot onto the screw conveyor at a speed of 750m/s. The kinetic energy of the impact produces additional heat, supports the bond and increases the density; the required hardness levels are achieved.
The screw conveyor is fully encapsulated with this method.
thickness of up to 0.25 mm is possible. The screw conveyor has the character of
a carbide screw conveyor combined with the benefit of toughness in the core.
Extreme torsion stress on small screw conveyors should however be avoided.
- No adhesions
- Longer process cycles, infrequent cleaning
- Improved service life
- Increase of surface hardness
- Reduction of surface reactions
- Reduction of friction
of servicing costs
|Type||Härte / HRC||Compostion||
Areas of application
||68 - 71||88% Wc / 12% Co||
Plasitc with high proportions of GF with a low corrosion effect, glass fibre, mineral, magnectic powder, filled plastics
|GT 1000 Ni||68 - 71||88% Wc / 12% Ni||
K-materials with high proportions of GF and corrosion effect e.g. VO
|GT 4000||55 - 65||75% Cr3C2 / 25% NiCr||Extreme corrosion effect e.g. PFA, POM, PMMA, PC, Fluorpolimere, Brom, PEEK|
|GT 9000||68 - 71||88% Wc / 12% Co + Microcarbide||Extremely high GF proportions with average corrosion effect|
We recommend the
above listed coatings for the respective applications:
The GT 1000 / GT 9000 coatings allow processing temperatures up to 450°C.
GT 4000 is suitable up to 600°C.