استانداردها

DIN 6914High-strength hexagon head bolts   DIN 6915 High-strength hexagon head nuts     DIN 6916Round washers for high-strength structural steel bolting   DIN EN 14399-4High-strength structural bolting assemblies for preloading – Part 4: System HV – Hexagon bolt and nut assemblies;English version EN 14399-4:2015,English translation of DIN EN 14399-4:2015-04