Fastener class

Parts of the international standard ISO 898-1 for bolts, screws and studs made of carbon steels and alloy steel.

The standard is applicable to bolts, screws and studs:

  • Made of carbon steel or alloy steel
  • Having triangular ISO metric screw thread in accordance with ISO 68-1.
  • With coarse pitch thread M1,6 to M39, and fine pitch thread M8x1 to M39x3.
  • With diameter/pitch combinations in accordance with ISO 261 and ISO 262, and
  • having thread tolerances in accordance with ISO 965-1, ISO 965-2 and ISO 965-4.

It is not applicable to set screws and similar threaded fasteners not under tensile stress (see ISO 898-5). It does not specify requirements for such properties as: weldability, corrosion resistance, resistance to shear stress, torque/clamp force performance or fatigue resistance.

Property classes (bolts, screws and studs): 

Fastener class Tensile Strength
Rm, nom 
Tensile strength (Min)
Rm min
Yield strength
Rp0.2, nom
Yield strength (Min)
Rp0.2 min
Elongation after fracture
d ≤ 16 mm
800 800 640 640 12
d > 16 mm
800 830 640 660 12
d ≤ 16 mm
900 900 720 720 10
10.9 1000 1040 900 940 9
12.9 1200 1220 1080 1100 8

Please note that the above information only are limited selections and rewritings from the standard. Additions and rules for practice and final end use are not presented in the above information. Therefore the information should not be used as a reference. Any use of the information is at own risk.
Subject to typing errors or changes.