Torque values are based on VDI 2230, edition 2015: The table lists maximum permissible tightening torques and the resulting maximum preload for hex cap screws and socket cap screws. Torque / preload values are applicable for other types of externally threaded fasteners also, as long as head strength and bearing areas are equivalent. The values are based on 90 % utilisation of yield point ReL/0.2 % yield strength Rp0.2. Clearance holes for bolts and screws acc. ISO 273-medium.
The listed values are maximum values and do not include a safety factor. This guideline assumes that the user has adequate fastener knowledge and is able to interpret the data accordingly.
Guideline for the following tables
The guideline values are somewhat higher than in the earlier version VDI 2230, edition 1986 due to higher usage of screw strength reserves. Higher preload during assembly can be obtained.
Tightening torque of following tables
With MA = FM · X, the tightening torque can be calculated for other preloads (assuming the same friction coefficient and same thread size).