according to ISO 898, part 5
The mechanical properties apply to set screws and similar, which are not subject to tension and which have threads of diameter from 1,6 to 39 mm, made from unalloyed or alloyed steel.
For further details of the mechanical properties of set screws please refer to ISO 898, part 5.
1) Property class 14 H, 22 H and 33 H are not for hexagon socket set screws