FERMO is a high-strength, flame hardening steel delivered by the producer prehardened to 250-290 Brinell. The steel can be flame hardened to a depth of 2-3mm (0.08-0.012 in.); the surface attaining a hardness of 56+/-2 Rockwell C. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on heat treating and joining. Filing Code: SA-439. Producer or source: Uddeholm Corporation.