Effect of Capping Front Layer Materials on the Penetration Resistance of Q&T Steel Welded Joints Against 7.62-mm Armor-Piercing Projectile

Abstract

In the present investigation, an attempt has been made to study the effect of capping front layers on the ballistic performance of shielded metal arc-welded armor steel joints which were fabricated with a chromium carbide-rich hardfaced middle layer on the buttered/beveled edge. Two different capping front layer materials were chosen for achieving better ballistic performance, namely, low hydrogen ferritic (LHF) and austenitic stainless steel (SS) fillers. On the other hand, the bottom layers are welded with SS filler for both joints. The consequent sandwiched joint served the dual purpose of weld integrity and penetration resistance of the bullet. It is observed that the penetration resistance is due to the high hardness of the hardfacing layer on the one hand and the energy-absorbing capacity of the soft backing SS weld deposits on the other hand. The complementary effect of layers successfully provided resistance to the projectile penetration. On a comparative analysis, the joint fabricated using the LHF filler capping front layer offered superior ballistic performance with respect to depth of penetration. This is mainly due to the presence of acicular ferrite along the bainitic structure in the LHF capping front layer, which caused a shallow hardness gradient along the weld center line.