Metric DIN 6340 iso equivalent Heavy Duty Hardened Washers are circular flat washers with a central hole that are thicker and have a larger outer diameter (OD) as compared to commonly used metric flat washer which is DIN 125. DIN 6340 Heavy Duty Hardened Washers are used where larger bearing surfaces are required as they have a larger surface area . DIN 6340 iso equivalent flat washers are mainly used for elongated holes.Bhalla Fasteners have the following sizes of DIN 6340 Heavy Duty Hardened Washers available for immediate shipping from stock having diameters ranging from M6 to M30 in heat treated hardened steel - tempered, hardness (350 + 80) HV 30.Bhalla Fasteners is the leading manufacturer, supplier and exporter of din 6340 washers to USA ,UK ,Poland, Germany , Austrailia, Ireland, and European countries.