DIN standard flat washer  covers the dimensional requirments of metric series FLAT WASHER.The standard of DIN standard flat washer  is DIN125 and DIN9021,Website:http://www.chinajinrui.net,  the former is nomal flat washer and the second is large washer the flat washer is widely used, mainly goes with bolt and screw. The mechanical property has 100HV, 140HV, 200HV and 300HV. StandardGradeFinshDIN125 DIN9021100HV     white zinc      yellow zinc black oxide      H.D.G       Dacromet      ...140HV200HV300HV