Experimental and Numerical Investigation on Ballistic Performance of Ultra High Hard Armour Steel Joints Welded Using Shielded Metal Arc Welding Process and Austenitic Stainless Steel Electrode

This study involves experimental and numerical investigation on ballistic performance of ultra-high hard armour (UHHA) steel joints fabricated using shielded metal arc welding (SMAW) process and austenitic stainless steel (ASS) electrodes. The ballistic test of UHHA-steel butt joints involves subjecting welded joints to 7.62 mm armor-piercing (AP) small arm projectiles. The weld metal (WM) and the weld interface (WI) are the areas of interest for the impact in ballistic test. The simulation approach of finite element analysis (FEA) that incorporates the model of Johnson–Cook and Mie Gruneisen equation of state (EOS) for the equations of velocity—Shock Rankine-Hugoniot. The scanning electron microscopy was employed to analyze the microstructure and ballistically tested regions of UHHA-steel butt joints. The hardness of the different regions of UHHA-steel joint was estimated using Vickers microhardness test. The results disclosed that the AP projectiles were arrested at the WM and WI, each exhibiting distinct depth of penetration (DoP) and width of penetration (WoP). These results align well with the FE model predictions. During projectile impact, a ductile hole growth was observed as plastic deformation pushes the material outward. When an AP projectile strikes, striations appear on the target plate's surface, observed both experimentally and in FE simulations. Additionally, the AP projectile becomes lodged at the WM. At the interface, the WM absorbs the projectile's movement, while the harder heat-affected zone (HAZ) disrupts the trajectory due to the soft/hard (austenite/martensite) interface. This behavior is elucidated by examining the WoP in impact region within the FE model.