C45 grade steel is a medium carbon steel offering moderate tensile strengths.
The material is capable of through hardening by quenching and tempering on limited sections but can also be flame or induction hardened to Hrc 55.
This grade is most commonly supplied in an untreated or normalised condition and is available in several variations (denoted by additional letters) which offer slight modifications of chemical composition.
Machinability similar to that of mild steel can be expected, however weldability is reduced.
C45 engineering bar available from Hillfoot
(*differs with section thickness and grade variation)