Rolled homogenized armour (RHA) grade steels are currently used in fabrication of Armoured Tracked Vehicles whereas its higher overall weight has forced the designers to develop Ultra High Hard High Strength Armour (UHA) steel.

The higher the hardness and strength of armour grade steel, the greater is the difficulty in making welds due to higher carbon equivalent number which makes the steel susceptible to HIC.

During fusion welding process, in which shielded metal arc welding process (SMAW) being the low heat input process depending on the heating and cooling conditions imposed on the structure yield strength of the base metal as well as the HAZ is altered.

Usually, the weld joints’ ballistic resistance is ignored, resulting in weld structure as the weak point and more vulnerable to the small arm projectiles. In this study, experimental and numerical ballistic performance of the welded Ultra-high Hard Armour (UHA) joint using Austenitic Stainless Steel (ASS) electrode are tested against 7.62 mm NATO ball and 7.62 mm armour-piercing (AP) small arm projectiles.

The weld metal and interface are the points of impact of the projectile. The Finite Element (FE) study was carried out using ANSYS workbench software with ACPPre and ACP- Post solver considering Johnsons Cook model and Mie Gruneisen EOS velocity – Shock Rankine – Hugoniot equations.

The results show that both projectiles stopped at weld metal and interface with different Depth of Penetration (DoP) and Width of Penetration (WoP) and have a good FE model agreement.

In both projectiles, ductile hole growth is observed with the plastic deformation pushes the material outward. During AP projectile impact, the target plate striation is observed at the top of the surface in both experimental and FE simulation.

This article is shared by S. Naveen Kumar, V. Balasubramanian, S. Malarvizhi, A. Hafeezur Rahman and V. Balaguru.