DIN9021 flat washer also known as fender washer, large outer diameter plain washer. Its OD is much bigger than standard DIN125 washer. It distributes clamping force over a larger area, protects thin sheet material and prevents surface damage. Material: carbon steel or stainless steel A2/A4. Surface: zinc plated, black oxide, HDG. Sizes M3~M24. Widely used in construction, machinery, solar brackets and timber assembly.
DIN125 flat washer is standard plain washer. It distributes bolt clamping load, protects workpiece surface from damage. Type A without chamfer, Type B with chamfer. Material: carbon steel or stainless steel A2/A4. Surface treatment: zinc plated, black oxide, HDG. Sizes M3~M24. Widely used in general machinery, construction and steel structure assembly.