8.8 is ISO 898–1 grading for Bolts and screws. It indicates a bolt/screw with tensile 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 used without Q&T provided they meet the hardness and tensile requirements.
EN8 is a medium carbon steel usually supplied untreated. EN8 has good tensile strength 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 can be further surface-hardened to produce components with enhanced wear resistance, typically in the range 50-55 HRC through induction processes. It is also available in a free-machining versions, EN8DM and EN8M (212A42)
<Elements available in EN8:
EN stands for European norms.
