Estudo do desempenho de aço carbono utilizado em blindagem balística de carros de combate

Abstract

This work analyzed a performance of a HHA (High Hardness Armour) armour steel plate, used in combat vehicles, through his microstructural characteristics, chemical composition, ultrasonic characterization, hardness and microhardness tests and terminal ballistics mathematical models. Based on damage effects caused by two Armour-Piercing 12.7 mm APM2 projectiles at the steel armour plate in which one of the projectiles caused a partial perforation and the other a complete perforation. Microstructural and ultrasonic characterization results showed that were more martensitic transformation at partial perforation region, with alternance between lath and needle martensites. At complete perforation region were detected more quantities of retained austenite and lath martensite, resulting in a region with less resistant of impact. These morphological differences were observed between profiles analysis of partial perforation and complete perforation regions. In the partial perforation region, more intense adiabatic shear bands were detected, while at complete perforation low intensity adiabatic shear bands were observed because more quantities of retained austenite, indicating a low ballistic resistance at this region. The microhardness values of martensite and austenite at partial perforation region are highest than other regions. The calculations of ballistic limit velocity and perforation energy demonstrate that a plate has performed satisfactorily according to American military standards for steel armour plates.