The design of advanced performance high strength low-carbon martensitic armour steels: Part 1. Mechanical property considerations

In a series of experimentally tempered martensitic steel alloys it was observed that for a given chemical composition, the heat treatment parameters for advanced ballistic performance are different from those required for higher mechanical properties, rendering the often specified relationship between mechanical properties and ballistic performance questionable. Systematic analysis of the microstructures and the fracture surfaces of 13 laboratory melted tempered martensitic armour plate steels was carried out to understand the improved ballistic performance of these steels of which the mechanical properties were actually lower than currently specified for military and security applications. It was, furthermore, observed that the detrimental effect of inclusions on ballistic performance depends on the tempering temperature and on the strain rate.