Abstract Lucefin Group C45, C45E, and C45R are medium-carbon (0.42–0.50%), non-alloy steels that are used in the normalized, cold worked, or quenched and tempered condition. C45E and C45R may also be flame or induction hardened. C45, C45E and C45R are widely used for moderately stressed parts. Owing to their low hardenability, their use in the quenched and tempered condition is not recommended for large sizes, as the improvement in mechanical properties over the normalized condition is insufficient to justify the additional cost of heat treatment. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on high temperature performance as well as forming. Filing Code: CS-203. Producer or source: Lucefin S.p.A.