The Nord-Lock Stainless Steel (EN 1.4404) washer is classified into the corrosion resistance class III. Our Wedge Locking Washers of this material are Surface Hardened & thus may start to discolour quicker under certain environmental conditions. However, this does not affect the functionality of the wedge locking washers.
In general, we recommend using 254 SMO® (EN 1.4547) washers (classified into corrosion resistance class IV) for outdoor applications.