DIN 9021 round flat washer, 6.4 x 18 x 1.6 mm, sst 72 h, Article number 90210641SST072. Property class / material: steel, surface finish zinc plated. Round Flat Washer manufactured to DIN 9021. Standard parts to the same standard, property class, dimensions and surface finish are interchangeable between manufacturers; confirm the controlling standard revision, any class-society or application approval, and the mating thread before substitution. Applications: load distribution and locking under bolt heads and nuts in machine building, structural steel, plant maintenance and marine outfitting.