Abstract: The invention relates to an air hardenable high-hardness steel for armoring applications, such as armor plate for use in light armored vehicles and body armor, and having a high level of ballistic performance relative to its plate thickness. In particular, the invention concerns a high ballistic strength martensitic armor steel which, in an air cooled and untempered condition, has a strength coefficient (s0) of higher than 2500 MPa; a flow parameter (P) of higher than 8.0, preferably higher than 18.0; and a manganese content of 1.8 to 3.6% by weight of manganese, preferably 2.8 to 3.1% by weight of manganese. The armor steel also includes retained austenite at a volume fraction of at least 1%, and preferably a volume fraction of 4 to 20%.

Abstract: A low-carbon martensitic armour steel comprises at least Fe, C, Si and Ni and has a ratio of yield strength to ultimate tensile strength of less than 0.7. The steel includes retained austenite at a volume fraction of at least 1%. The low-carbon martensitic armour steel can be prepared by subjecting a steel which comprises at least Fe, C, Si and Ni and which has a martensite start temperature of less than 210° C. to an austenisation heat treatment step at a temperature of at least 800° C., quenching the steel, and subjecting the steel to a tempering step at a temperature of less than 300° C.

Abstract: The invention relates to an air hardenable high-hardness steel for armouring applications, such as armour plate for use in light armoured vehicles and body armour, and having a high level of ballistic performance relative to its plate thickness. In particular, the invention concerns a high ballistic strength martensitic armour steel which, in an air cooled and untempered condition, has a strength coefficient (s0) of higher than 2500 MPa; a flow parameter (P) of higher than 8.0, preferably higher than 18.0; and a manganese content of 1.8 to 3.6% by weight of manganese, preferably 2.8 to 3.1% by weight of manganese. The armour steel also includes retained austenite at a volume fraction of at least 1%, and preferably a volume fraction of 4 to 20%.