COMPOSITE STEEL ARMOUR Russian patent published in 2011 - IPC F41H1/02 F41H5/04 

FIELD: military hardware.

SUBSTANCE: steel armour consisting of composite armoured plate made in the form of monoblock. Armour includes front steel layer, intermediate steel layer and rear steel layer. Front layer is made from high-strength steel with hardness of 58...64 HRC, intermediate layer is made from low-carbon steel with hardness of not more than 20 HRC and thickness of 0.01…0.05 of armoured plate thickness, and rear layer is made from armoured steel with hardness of 52…56 HRC.

EFFECT: improved protective properties of body armour at protection against bullets with heat-hardened cores.