Grade Markings for Metric Fasteners

Markings of Screws

(According to ISO 898 - Part I)

Property Class 3.6 4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9
Marking 1),2) 3.6 4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9
1)The full-stop in the marking symbol may be omitted.
2)When low carbon martensitic steels are used for property class 10.9 the symbol 10.9 shall be underlined: 10.9

 

Identification with the manufacturer's mark and the property class is mandatory for hexagon screws 3.6 to 12.9 and socket head cap screws 8.8 to 12.9 with thread diameter d> 5mm, where the shape of the screw always allows it - preferably on the head.
Head Markings for Hex Head Head Marking for Socket Heads
Examples of markings on hexagon screws. Examples of markings on socket head cap screws.


Marking Of Nuts

(According to ISO 898 - Part II)

Property Class 04 05 4 5 6 8 9 10 12
Either designation Symbol 04 05 4 5 6 8 9 10 12
Code (Clock Symbol) Symbol Nut Class 04 Nut Class 05 Nut Class 4 Nut Class 5 Nut Class 6 Nut Class 8 Nut Class 9 Nut Class 10 Nut Class 12

 

Identification with the manufacturer's mark and property class is mandatory for hexagon nuts with thread diameter d > 5 mm.  The hexagon nuts must be marked with an indentation on the bearing surface or on the side or by embossing on the chamfer.  embossed markings must not protrude beyond the bearing surface of the nut.

*All information is strictly informative