8.8 is ISO 898–1 grading for Bolts and screws. It indicates a bolt/screw withtensile strength of minimum 800MPa and a yield strength of 80% of 800MPa = 640MPa.Depending on thickness these are either quenched and tempered or can also be usedwithout Q&T provided they meet the hardness and tensile requirements.
EN8 is a medium carbon steel usually supplied untreated. EN8 has good tensilestrength and is often used in applications such as: shafts, gears, stressed pins,studs, bolts, keys etc.
EN8 is a very popular grade and is readily machinable in any condition. It canbe further surface-hardened to produce components with enhanced wear resistance,typically in the range 50-55 HRC through induction processes. It is also availablein a free-machining versions, EN8DM and EN8M (212A42)
<Elements available in EN8:
EN stands for European norms.