These DIN 6923 flange nuts are carbon steel hex nuts with an integrated flange, and the flange face carries a ring of angled serrations instead of a plain washer face. The serration does the work: as the nut tightens, the teeth bite the mating surface and resist backing out, which is why the same part is sold as hex flange lock nuts. The flange spreads clamp load over a wider area, so a separate washer is often unnecessary and assembly needs one part less. The published table runs from M3 to M24, with serrated flange nuts in M6 to M20 held for spot supply in grade 4.8 / 5.8, in blue-white or yellow zinc. Thickness, flange diameter, coating, marking and packaging can be customized.