Approval of fastenersSP is testing fasteners with regard to corrosion protection ability in different operating environments. The method provides an answer to which corrosion protection class the inorganic coating has.
SP has, in cooperation with surface treatment companies associations SYF and Nordic Galvanizers, developed a method that describes corrosion protection class of inorganic coatings on steel - Nordtest NT MAT 003.
The principle of the method is to determine the corrosion protection class of a product by simultaneously exposing the sample and reference coupons of steel and zinc, used for measuring the corrosivity of the environment. The corrosion protection class determined in the Nordtest method is redarging 15 years lifetime. Exposure is performed in accordance with ISO 11997-1 Method B, which is an accelerated corrosion test consisting of intermittent salt spray test and humidity cycling. This corrosion test method is identical to that described in VDA 621-415.
Purpose and application
The method is currently used mostly in connection with the approval of fasteners, but can also be used for other products with inorganic coating.