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Alloys & Coatings

It is important to choose the correct construction materials and coatings in order to maximize wear life and enhance process stability.

The majority of screws are still manufactured from nitriding steels but at Cooper Technology we offer a broad range of special base alloys including Tool Steels and Powder Metallurgy (CPM) alloys.

For highly abrasive or corrosive applications we can offer an ‘Extreme Coating’ – typically an 88 % Tungsten Carbide HVOF deposit.

The Extreme Coating can fully encapsulate the screw or a ‘Flight Guard’ deposit can be applied to the screw OD only. The coating is sprayed at supersonic speeds forming a true metallurgical bond. C-1000 is the most common deposit. It comprises 88 % Tungsten Carbide and 12 % Cobalt. This offers exceptional wear resistance. Other deposits are available including C-9000 designed for sub-micron particle abrasion.

After deposition the Tungsten Carbide deposit is diamond ground to achieve finished OD tolerances and a surface finish ranging from +/- 140 RMS to 16-32 RMS. The latter rivals chrome plating in appearance. 


Xaloy X-8000


X8000™ is a thermal spray coating applied to the screw. It is then fused to ensure a full metallurgical bond.  This material complements Xaloy’s high abrasive resistant X830 overlay and is well suited for processing highly filled or corrosive resins. It can be applied for the full flight length or only on isolated areas of the screw that are more susceptible to wear.

Benefits of X-8000

  • Tungsten carbide cladding – improved wear and superior corrosion resistance

  • True metallurgical bond

  • Complete Xaloy Wear System – for the ultimate in wear protection:

    • X8000™ carbide cladding on the screw root surfaces.

    • X830 carbide hardfacing on screw flight OD.

    • X800® patented carbide barrel lining.

  • Rebuilt Screws – X8000™ is repairable and can be applied to your rebuilt screws greater than 50mm diameter

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