PTA welding of hard-face flight screws
For armouring hard-face flight screws we employ the plasma powder arc welding process (PTA). The animation demonstrates the production cycle.
For screws as of an outer diameter of >65 mm, hardened-through screws made of tool steel are generally no longer economical to manufacture. To realise an effective wear resistance on the screw flights that are exposed to wear the most, the flights are coated with an armour coating.
Powdered hard-facing alloys based on cobalt, nickel or iron are applied on a plant that is modified according to the respective requirements. A broad spectrum of hard-facing alloys is available.
Special iron-based, hard-facing alloys, high in vanadium, can be welded on flawlessly as flight armour. The many years of expertise guarantees a subsequent perfect machining with the best results and highest wear resistance of the screw flights.
Subsequent nitriding additionally protects the screw root and screw flank from wear.