Bolt tensile strength

DIN EN ISO 898-1 (2009-09)
DIN EN ISO 3506-1 (2010-03)

The strength of standard ISO metric steel bolts is readily identified by means of a numerical code.

The code is comprised of two numbers separated by a dot. This dot is not a decimal marker but is merely a means of separating the two parts of the code. The number to the left of the dot when multiplied by 100 provides an indication of the Ultimate Tensile Strength (in MPa) while the number to the right when multiplied by 10 times the preceeding number gives the Yield Strength (in MPa)

Example: 8.8
Tensile Strength
8 x100 = 800MPa

Yield Strength
8 x 8 x 10 = 640 MPa