10.7 DIN EN ISO 898-1 | DIN EN 20898-2 Strenght values

The strength class identification consists of two numerals:
– the first number corresponds to 1/100 of the nominal tensile strength in N/mm2 (see table)
– the second number shows ten times the ratio of lower yield point ReL (or 0.2 % yield limit Rp 0.2) and nominal tensile strength Rm, nom (yield point radio).
Example; Strength class 5.8 means
Minimum tensile strength Rm = 500 N/mm2
Minimum yield point ReL = 400 N/mm2

The designation of a strength class consists of a distinctive number which provides information of the test tension of the material used:
– distinctive number x 100 = test tension Sp
– the test tension is equal to the minimum tensile strength in N/mm2 of a bolt which, if paired with the appropriate nut, can be loaded up to the minimum yield of the bolt.
Example: Bolt 8.8 – nut 8, connection can be loaded up to the minimum yield point of the bolt.