Carbon Technical Information

Corrosion protection

The coating of the Powell Gee self drilling screw is a vital factor in its useful lifespan.

500 hr PLUS Coating


What does this mean?

This is our brand name for the anti-corrosion coating which protects all Powell Gee self drilling screws, and will resist up to 500 hours in a salt spray test.
500 hr PLUS is a high technology coating, mainly consisting of epoxy resin containing finely dispersed zinc and aluminium particles

Production Process

The pre-hardened screws are coated by a dip, spin, bake process with oven temperatures not exceeding 200°C. This produces a multi-layered, scratch resistant coating.

The process is also environmentally sensitive as it does not use any contaminated waste product such as the Cr6 poison, unavoidable in certain galvanising/electro plating processes.

How does 500 hr Plus compare to other coatings?

Powell Gee self drilling screws undergo 2 tests to determine the quality of the corrosion protection:

  • The Salt Spray Test (DIN 50021 SS)
    Used to test how long a screw can resist an aggressive salt spray environment before corroding.
  • The Kesternich Test (DIN 50018)
    Used to test how long a screw can resist an aggressive acid based industrial environment.

Please note that the following figures have been achieved under laboratory conditions and do not allow for any safety factors. Testing cannot take into consideration all possible combinations of screws and materials.

* Over 6mm limited due to Tensile Strength.
¹ Values refer to diameter 4.8mm.
² Values refer to diameter 5.5mm.

Test results have been obtained in conjunction with St-37 steel by an independent test laboratory.