Studies on the role of microstructure on performance of a high strength armour steel

This investigation describes and analyses the experimental results pertinent to the ballistic performance of two apparently identical low alloy high strength steel plates against deformable lead projectiles at a velocity about 840 m/s. All the tests are carried out at normal impact angle, i.e. zero obliquity. One plate stopped all projectiles fired at it. However, the other plate failed to stop the projectiles at some locations. Both the plates were subjected to detailed analysis using standard metallurgical techniques to identify the cause of failure in one plate. The experimental results presented include the variation in the microstructure, hardness and retained austenite of the two target plates. The study concludes that the failure is caused by the decrease in resistance of the plate possibly due to higher retained austenite and coarser martensitic structure.